Radio World, 1922-1923

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UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN OAK STREET Digitized by Google

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tveral Valuable Hook-Ups IC. a Copy. $6 00 a Year S3 Nuatan ▲ ILLUSTRATED T UBLISHED EVEKV SEVEff T> A y S WBAY, New York, Will Broadcast Personal Messages'* (Photo by Morn» Rosenfeld, New York) The radio transmitter forminf the heart ot WBAY, the broadcasting station of the American Telephone and felegreph Company, la shown In the accompanying oho to graph. It is located on the upper floor of the company'* building, on Walker Street, New York City. The tubes are mounted in the upper part of the framework of the transmitter (See •). This location I* used because' It provides adequate ventilation. The current for heating the filaments is supplied from a con- stant potential generator. Means must be provided, in the radio operating room, so the radioman in charge can see at once just what power is being' used. 1 and 2 indicate the two meters which are the telltales of the direct current flowing. These meters register the amount of current used. 3 indicates the rheostat and the protective) devices which cut. In or out, the units of the eat. In order to operate these instruments the necessary electric feed wires must bo brought to the panel by con- duit pipes. These pipes are indicated by 4. Not only must the electric-power wires be run in a conduit pipe, but the conduit pipe must be grounded, as shown In the photograph. The ground clamp is fastened to the panel by screws. It runs to each pipe where It Is gnwindsd This prevents the high-frequency current that Is being generated m the air surrounding the instruments to become affiliated with the low-frequency currents, pre- venting the generators from being ruined. The next step Is to force the necessary current to the vacuum tubes. Here Is the moat critical and Important • tage of the transmitter. This Is where the operator must know what the vacuum tubes are doing. The only method employed is the use of meter*. These) electric meters are somewhat like the meters indicated by 1 and Z. S indicates the necessary meters which permit the operator to know how the vacuum tube* are working-. The frequency of the transmitted energy (wave length) is controlled by the value of the inductance in the oscil- latory circuit, which includes the antenna. This In- ductance Is adjusted by means of a variometer, indi- cated by I. A variable condenser, connected serosa the plate -coil, controls the plate current through the oscil • la tor tubes. This condenser consists of a variable unit in parallel with two fixed units which may be switched in or out of the circuit. The variable unit is controlled by a knob on front of set 7. iU WANT TO INCREASE YOUR WAVE LENGXTJ Pact* 4

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RADIO WORLD MICROSTAT VERNIER RHEOSTAT The Most Sensitive Filament Control Quickest-Easiest Tuned Ten times the possibility of exact filament adjustment as over the ordinary wire rheo- stat. Eliminates Grating and Interfering Noises Single Knob Adjustment This microstat is far more durable than any ordinary rheostat; is made of better material with greater care. Order through your dealer or delivered to any part of U. S. $1.40 The microstat takes up less room on the radio board than any other rheostat. Is neat, compact, and particularly designed for those who want the best in radio material. This device is made under the most exacting supervision, and each part is carefully and accurately machined. A template and full instructions in each box, so you can quickly and satisfactorily place the microstat on your set with the greatest ease and neatness. The exact calibrations of the microstat are due to the gradual entering of two points into the resistance material of our own composition, which gives us exact- ing and most minute measurement of current to the filament, as the operator brings the two points together or separates them thru the screwed handle. MICROSTAT COMPANY WILLIAMSPORT, PA. Digitized by Google

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L /.V. '.: RADIO WORLD [Coprricht, 1922, by HennessT Radio Publications Corp., New York, N. Y. Entered at second -crass matter, March 28, \9U, at the Poet Office at New York, N. Y., under the act of March J, 1E79.] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Pub- lication* Corporation from Publication Office, 1493 Broadway, New York, N.Y. Telephone i Bryant 47ft Vol II, No. 1 September 30, 1922 15c per copy, $6.00 a In the Heart of a Navy Seaplane THERE is nothing complicated about radio reception. It proved its merits when the "Sampaio Correia," the Brazilian seaplane left New York City on its flight to Brazil. The accompanying photograph gives a splendid view of the radio installation aboard this "ship," and it shows what can be done in a similar way on any heavier-than-air vessel. The re- ceiving-set consists of a tuner and amplifier unit. A fixed antenna is strung between extremities of wings and tail structures. This makes it possible for the pilot to pick up any messages forwarded which will enable him to make such changes in his course as he desires. Weather reports, storm warnings that are broadcasted hourly are of vital importance to the aviator and it is only by radio that he can get them. Seaplanes are also equipped with radio-compass outfits. Here is WVP, Bedloe Island's Big Radio Station IC K.iUo Corporation of America.. ) Interior of the pit of an airplane showing how the radio apparatus la placed, composed of a tuner and amplifier connected to a fiaed i The set is THE radiophone service of the future is possible to every- one who is provided with a suitable receiving-set. All that is necessary is some kind of aerial, which, for this purpose, may be a single wire, elevated 30 feet or more above the ground and running more than 100 feet, if possible. This To the right in the photoeraph you will aee the antenna of WVP on Bedloe's Island, N. Y. will enable the operator to have a receiving-set that will permit him to listen to the broadcasts on 300 meters. With a somewhat longer aerial, it may be possible that we shall employ a longer wave-receiver and utilize the longer waves used in radio. For this purpose we could listen to WVP. the Signal G>rps station of the United States Army located at Fort Wood. Bedloe's Island, N. Y. There is nothing more fascinating than listening to a radiophone concert and service. One turns the tuning handle of the receiving set and. finally, when the tubes are lit, one is able to hear the broadcasting. It is well to remem- ber that the radiophone is subject to the noise dreaded by all radio- men: atmospheric disturbances, or static — and. often, QRM. This is not so had when listening on 1-450 meters for WVP. The accompany- ing photograph shows the towers and aerial of the Fort Wood station. Digitized by Google

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4 RADIO WORLD Increasing the Wave Length of a Receiving Set By George W. May, R. E.ST7 Figure 1 — Inductance coll in series with single- circuit receiver, the details of which are rally described in the accompanying article. Drawn by S. Newman WHAT must I do to my set in order to hear the longer wave- lengths? This question is asked by many fans who wish to listen in on stations with a wave length in excess of 600 meters. Although simple as it seems, the principle of loading up must be properly followed out, pro- vided long wave-reception is desired. On these long waves — such as 1450 meters, which is above the average wave-length of receivers generally used — some means of increasing inductance must be made. The average receiving- set is capable, ordinarily, of operating only over a comparatively narrow band of wave lengths. This should not be considered a great fault, because sets may be made to operate more ef- ficiently over a narrow band of wave- lengths than over a wide band of wave- lengths. Occasionally one wishes to hear stations operating on the higher wave-lengths — higher than those af- forded by the tuning-coil gear on one's Figure 2— Inductance in series with primary and secondary of an Inductive type receiver. Both elements must be loaded to obtain resonance. set. In all cases, the range of wave- lengths of the receiving set is increased to higher waves by means of the load- ing coil, or inductance. This means that more inductance must be added to the inductance already in the set. This instrument may take a number of forms such as tuning coils or honey-comb coils. It is known that there are two cir- cuits, namely: single- and double- circuit receivers. If vacuum tubes are employed, there also may be regener- ation in both cases. In the single- circuit short-wave receiving sets — usually made up of a tuning coil and variable condenser in series with the aerial and the ground — have the crys- tal detector and telephones in shunt to the coil. Now, if longer waves are desired, simply add another coil in series with the aerial and ground. Re- member, this coil is in series with the coil in the set. There must be a sufficient number Figure J— Vacuum tube receiver of the inductive type. Primary and secondary have Inductance for increase in wave length as well as the tickler coil for regeneration. of turns depending upon the maxi- mum inductance of the other coil in the set. Remove the condenser in series and place it in shunt to both coils. The detector remains the same, whether crystal or vacuum tube. When a two-circuit receiver is used, another coil must be connected in series with the secondary in order to balance the two circuits. If a loose-coupler is in use, a moderate amount of loading may be used in the primary circuit without any in the secondary as sec- ondaries of this type instruments are usually wound with more wire to com- pensate for the slight loading. If the circuit in use employs a vacuum tube as a means of regener- ation, or in conjunction with a tickler coil, the question of loading up for the longer waves is a little more diffi- cult as in the double-circuit receiving- set we must load up the three coils, namely: primary, secondary, and tick- ler coil. Gave Him the "Double Throw" By Jack Turner Radio Editor, "The Age-Herald," Birmingham, Ala. 1SAW Ray D. Owe downtown the other night, and with him was Anne Tenna. I had told Ray that I would like to "meter," so he intro- duced me and I asked her if she wouldn't like to have a "feed, back" around the corner, and she said that it would just "tickler" to death. When we went in, she took off -her hat and I saw that she had her hair done up in "short" "continuous waves," and wore a "switch" or two. She said she just "came in" town. I asked her what "station," and she re- plied, "The 'Terminal'." I said to her, "You are the 'cat's whisker' — you have eyes like 'crystal' — I 'solder' like you." When I told her that I was going to kill a mosquito that kept buzzing around my head, she said, "kilowatt?" Anne ordered so much that I thought she would "choke," and when the We have not as yet found out even an infinitesmal part of the many things radio will do for mankind. — Prof. J. A. Fleming Digitized waiter brought a cake that was full of "currents," I broke my "plate." There were many people there "an- tenna" them were dancing. I asked Anne for a dance and she didn't offer any "resistance;" but we didn't have much "selectivity" as I could only do the "one step." She told me that I danced like an "amateur." Once I hit the "ground" when I did a "loop." But she couldn't dance much "ether." After dancing with me once, she would re"fuse""if I asked her for an encore. While I was talking to her, she told me that I was a "loud speaker" and that I "broadcast" everything I said. When the waiter "brought in" the check, I told him to "charge" it. I asked her, " 'Wire' you in such a hurry?" She answered: "I must go 'ohm' because I don't want to get 'insulate.' "

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RADIO WORLD 5 The Importance of the Variometer to a Receiving Set Figure 1. The in of the variometer as a vari- able inductance in the inductive-coupled receiv- ing-set. Drawn by S, Newman. A SIMPLE means of tuning-in a radio set is afforded by the variometer. This piece of ap- paratus, widely known, is one of the instruments that tend to make up a certain type of regenerative set. In its simplest form it is quite easy to make and parts for its construction may be easily purchased and assem- bled. A variometer is particularly adapted for the construction of radiotelephone receiving sets. They effectively cover a wave-length range from 150 meters to about 600 meters. A variometer is built up of two spherical coils. One which revolves, is termed the rotor; the other, which remains stationary, the stator. The rotor, or secondary coil, turns about its axis inside the sta- tionary coil, or stator, which acts as the primary. The variometer, as its name signifies, is a variable type of in- ductance, but it is different from tapped coils, or coils with sliders, in this respect: there is no variation in the length of wire. In the inductance of a variometer, the variation is ac- complished by the rotor revolving in- side the stator, or primary. This proves that the elimination of multi- ple point, or tapped switches, permits variation without any break in the cir- cuit whatsoever. With this important feature, the variometer is adapted for the vacuum-tube work, since switches or taps are likely to leave a break in the circuit when the set is being tuned. A variometer with a rotor shaped like a ball, is known as the ball type ; another type" consists of two cylindrical tubes, one rotating within the other. This type variometer does not have a minimum or as high a maximum in- ductance as the ball type. The best variometers have a minimum clearance between the rotor and the stator, and both coils have the same inductance. It may be then said that a variometer is a tuning coil in which the primary coil is fixed and the secondary coil By Donald Van JVyck movable and revolving at right angles to the primary. One end of the pri- mary is connected to one end of the secondary. It has no sliding contacts or other means of varying the induct- ance of the primary and secondary coils, but tuning is accomplished solely by varying the coupling between them. This is what happens in the variom- eter when the tuning adjustments are made by turning the variometer dial. When a current flows through the coil — in this case the stator — a mag- ■'Antenna VannmeWrJ VarCond uerecmr 'Ground Figure 2. The use of the variometer aa a direct- coupled tuning transformer, well adapted for short-wave reception. Drawn by S. Newman. netic field is set up about the field sur- rounding the wires. When the current in the coil is varied, there will be a corresponding variation in the mag- netic field. If another coil, the rotor, is placed in proximity, the changing magnetic field will induce, or set up, a voltage in the secondary coil. Con- nected to the second coil — or, as it is known the secondary — is a detecting Argentine Fans to Build American Sets ARGENTINE radio fans soon will be building receiving sets along the lines of the specifications issued by the United States Bureau of Standards. Believing in the development of radio, especially in the efforts of the United States Bureau of Standards to simplify and standardize home- made or assembled sets, the Argentine Em- bassy has just completed the translation of the Bureau of Standards illustrated reports on building simple and two-circuit radio re- ceiving sets at home. These pamphlets, which were popular in this country, are ex- pected to be equally as popular in the Argentine now that it is in Spanish. Radio Catches Everything IN a radio broadcasting studio the ab- sence of a visible audience often makes a singer forget that several thousand people may be listening to him. Such was the case with a soloist at one of the local sta- tions recently. At the end of a fine- tenor solo, listeners heard the singer say, "How do you shut this thing off, anyhow?" , Inner Rotating Coil Stator- Figure 3. View of variometer giving range of inductance variation than some of the other types of variometer. This is known as the ball type. Drawn by S. Newman. device such as a telephone receiver, which records the change of current. The induction of current from the primary to the secondary is termed mutual induction. In two of the circuits illustrated, the use of the variometer in Figure 1 is shown as a variable antenna-induct- ance; while in Figure 2, the use of the variometer as a direct-coupled tun- ing transformer is shown. This cir- cuit is particularly suited for the shorter wave-lengths, such as 200 to 500 meters. A large range of wave- length variation cannot be obtained from a variometer when used as the sole tuning-element unless it is made very large and wound with a large number of turns of wire. The circuit shown in Figure 2 has been used for long waves using a large variometer and a vacuum-tube detector. The mani- pulation of the variometer is very simple. Figure 3 shows a variometer used in a regenerative vacuum-tube set. One variometer is placed in the grid and the other in the plate circuit. Any circuit that gives regeneration is called a feed-back circuit, from the fact that oscillating energy is fed back from the plate circuit to the grid circuits. There are several feed-back circuits. The two most commonly used in radio re- ceivers are the "tickler circuit" and the tuned plate, regeneration being accom- plished by employing the variometers. In this case, the inherent capacitance between the grid and plate is relied on for coupling. The choice among dif- ferent forms of feed-back circuit lies in convenience, Digitized oi ieea-DacK circuit

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6 RADIO WORLD Successful Stunts of an Amateur Radioist Adjusting Diaphragms on Receivers HAVING different makes of re- ceivers on hand, including some cheap ones, 1 tried to make some of the low-priced low-ohm re- ceivers more sensitive. I was success- ful with all. Looking them over, I noticed that they varied in length from the mag- net to the diaphragm, and as the more expensive ones were of standard length and much closer, I tried to duplicate them by cutting down the outside edge of the rubber on which the diaphragm rests, thus permitting the diaphragm to come closer to the magnet. By so doing, I expected in- creased action due to a stronger mag- netic field. The cutting of the rubber was easily accomplished by laying fine sandpaper on a smooth table, and gently rubbing the body of the receiver over the paper. If you happen to take off too much, you can place paper washers under the diaphragm to raise it from the mag- net. You had better use a straight-edge rule to see how far the magnet is from the diaphragm as it may be too close and be the direct cause of a tinny sound. You may wonder why the receivers on a head set do not sound alike — one By C. F. Rye will be louder than the other. Try them with a straight-edge rule and see if the diaphragm of one is not in a stronger magnetic field than the other. If so, try to bring the weaker up to the stronger, either by shimming with paper, or removing the bearing por- tion of the body where the diaphragm rests on it. I have made a big improvement in my receivers of cheaper make by the method I have here explained. Many of the receivers have metal bodies in- stead of rubber. The only difference is that the metal takes more rubbing, but the result is the same. * * * Using Mercury on Galena AFTER looking over my crystal set to see if I could improve on any of the connections in order to help the weak current on its way, I remembered that in only a few places was the crystal sensitive. The thought naturally came to me: How about the places where the crys- tal rests in the metal cup? Are they sensitive? Well, to eliminate doubt, so far as possible, I used some cold solder and . a drop of quicksilver, or mercury, as a bed in the cup in which to lay my crystal. The mercury dissolved the solder Seen at London's First Radio Show # r.4 A * ~ V (C Central Newt Photo Service) Radio on motor car* adds to their luxury! This waa shown at the First Radio Exhibit held in London. In tho ancient, venerable halls of Westminster, modernity bold sway. A motor bos was fitted np with a receiving set, as seen In the photograph. All you see Is the receiving apparatus safely ensconced below the back seat and a bright parasol resting casually in front. Tho parasol, on further Investigation, la a loop aerial, by the aid of which one may ride out to the country and enjoy Ufa. Of course, tea was served at this British radio show, for tea is a necessary element at every British function. This show waa the first bald in tho British metropolis and waa largely attended. and made a thick mixture which grad- ually hardened and made a metal con- tact all the way through, improving the strength of signals. I used mercury in a similar way on a piece that was mounted when I bought it, and this piece also was greatly improved. My purpose in doing this was to overcome the evil which often occurs in mounting galena — overheated metal in which the galena is placed. Such overheating causes a thin coat, or film, to gather on the outside of the galena. Later, I cleaned other parts in my hook-up where it was impractical to solder, and gave it a coating of quick- silver, or mercury. I can assure you this operation did no harm. * * * Disconnecting a Soldered Joint Cold IN my desire to secure the very best results from my set and eliminate all noises, I had to solder my joints. This worked well until I wanted to change my connections, as illustrated in a magazine. Then I had to think, as some of the joints were in places where I could not heat them without damaging my set. After trying to disconnect the joints I used mercury, or quicksilver ; and all that was needed was to clean a place on the solder and apply a little mercury to the cleaned spot. In a little while, the joint was free and ready for a good connection to any other place, as it had a mercury coat on it that helped to make a good connection — just as a wet hand makes an electric connection. In this case, no solder whatsoever was needed ; yet all the good qualities of a soldered joint was accomplished with excellent results. * * * Two Aerials Instead of a Ground MANY amateurs have a poor chance to make a good ground My best results have been secured without any ground — with less trouble even than digging a hole to bury cop- per wire. My plan is this: I set up another aerial and ran my ground connection up to it. My signals — on a crystal set — were loud enough to be heard a hundred feet away with the aid of a horn. I have a good ground to the water- main, but I prefer my second aerial. My two-aerial plan may be accom- plished by using one of the wires of * double-wire aerial. Digitized by Google

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RADIO WORLD 7 Employing Jacks with a Two-Stage Amplifying Receiver By Fred. Chas. Ehlert Variometer 6 Volt 45 Volt Variable Storage Salt, B- Battery tie diagram of a regenerative tat, •mplsrinf *i aa muy ataaae aa ha deelrea. Tha by a m of tataaaratioaj, Jacks ara atflJbed a* the atajraa, which ahowa la tha circuit at tha ncaed ataa* aeay a* Uft ta or ant. T Sunaatad by Fred. Chaa. Ehlart. Draws by S. Newaua. TO many experimenters, a two- stage amplifying receiver rep- resents a more difficult prob- lem than it really is. However, it raises important points which can- not be overlooked. The accom- panying circuit is a most efficient outfit employing jacks. It is a cir- cuit no amateur should overlook. Each and every part is shown. It may be assembled in an efficient way. It will not tax the financial resources of the average radiorran. If experimenters have the material handy, I would suggest that this hook-up be put to the test. One thing that must not be overlooked, however, is the wiring. If leads are run back and forth over the set, there is sure to be trouble from "howling" because of the feed-back effects between the grid and plate circuits of the various tubes. In some equipped sets elaborate pre- cautions have been taken, with grounded shields between the steps. Practically all amplifying sets are equipped with jacks. Therefore. I I have included these jacks in this circuit. The detector jack is of the double-circuit construction. The first stage is, also, that of a double- circuit jack ; in the last stage, an open single-jack is employed. Where it is necessary to run wires close together, slip some spaghetti tubing over them. When mounting the transformers I suggest that this be done at right angles to each other. If all my sug- gestions are carefully followed, no tube noises — such as howling — should be experienced. The detec- tor plate-circuit should have, ap- proximately from 18 volts to 22 volts, while the amplifying plate- circuits should range about 45 volts plate-current. A 6- volt stotage battery will be sufficient to light the three tubes, but it is suggested that the amateur get a large ampere- hour battery from 80 to 100 ampere- hour capacity. This will permit bat- teries to furnish necessary power to the tubes, for a long time, with- out the troublesome necessity of placing them on charge. This Discovery May Elim- inate the "Catwhisker" By E. Farig, PhD. BY means of high pressure, and at a temperature of 1600 degrees Fahrenheit, or 1593 degrees centi- grade for four hours, metals of a low-melting point (850 degrees Fah- renheit) lose all their original char- acteristics. They become infusible, cascade, in form of crystals — hard, brittle, sparkling all over, and have radio-crystal rectifying properties. Pieces tested on a 300-meter wave- length, recorded speech and music per- fectly— no screeching — and eliminated ttie tiresome catwhisker hunt for a sensitive spot. Tests will be made with alloys to insure a uniform though sen- sitive rectification. This same discovery was tested, tak- ing the place of lead batteries, elements in storage and under these tests gave very promising results. This crude substance "metaloid," is a new product not yet known to science. The treat- ment for rectifying is simple and the mounting of these crystals offers no difficulties. The best rectification quality I have found, is a passage of current of from .02 to .04 M-A ; whereas 5 M-A is of no use. I think this discovery is of sufficient importance to let the industry know what is being done by research engineers. Radio and CONDUCTORS AflMetab Conductors Insulators INSULA- NON-CON- TORS DUCTORS Dry Ah? Watar Me at Earth MatalBcOraa AataMlFmida Ptoaabaa* Acid Sola than Lhr'at Vmlahla Sorattoaa Saliaa Samtiama Mica Was Jet Rea<a Salahar Parmffta Dry hat Bakallte Volume I of Radio World Now CoeapUta If too did not frrt copies of Radfo World No. 1 to No 26. send us $3 00. Or we will tend you this paper lor one year, ($6.00 (or 52 issue* ) and start it with otrr first issue, which will be mailed yam at soon as possible after rece»v* of. order. Digitized by GoOglC

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t RADIO WORLD Why it is Possible to Operate with a Vacuum Tube By John Kent (C. Ewing Galloway. N. T.) Tjrpa of Vacuum Tubes RADIO frequencies lower than 20,000 are seldom used. If they were impressed on telephone receivers, the note — even if the receiv- ers would respond — would be inaudi- ble since the ear will not record fre- quencies much above 15,000 cycles. The problem is to reduce the frequency used in radio so it will not be inaudi- ble in telephone receivers. This is ac- complished by the detector, an instru- ment which groups a number of cycles of high-frequency current and deliv- ers them as one cycle of low-frequency 9 audible in the telephone receiver. De- tectors are made in many shapes and forms. One of the best detectors ever invented is the vacuum tube. This in- strument was perfected about 1910. Since that time, its use has been in- creasing daily. The vacuum tube consists of a evacu- ated vessel somewhat similar in size and construction to a small incandescent- lamp. Instead of two connections — made in the case of the electric lamp — as generators for the delivery of electromagnetic waves for radio the vacuum tube, or, more properly, the electron tube, has four connections. Two serve the same purpose as those of the incandescent lamp; namely, to light the filament. The other two con- nections lead to two new elements known as the grid and the plate. There are, therefore, three elements in the vacuum tube — filament, grid, and plate. These elements are arranged with the filament in the center ; the grid on the outside of the filament and the plate outside the grid. The filament consists of a tungsten wire ; the grid of a small coil, or mesh of wires ; and the plate of a thin sheet of metal. The tube operates as fol- lows: A 6- volt battery is connected to the filament which, when lighted, shoots off small particles of electricity in every direction. A battery of 22 volts is connected with the positive side to the plate and the negative side to the filament. When the battery is con- nected, the small particles of electricity which are shot off from the filament. and which are negative in character, are attracted to the positive plate. Therefore, a current flows between the filament and the plate. If a third battery, or an alternating current such as that due to a signal, is connected to the grid — and the voltage of the grid is changed — it will be found that the current flowing in the circuit formed by the plate and filament, will vary in exactly' the same manner. The variation, however, will be much great- er than the small voltage impressed on the grid would warrant. The current will increase when the grid is positive, and decrease when the grid is nega- tive. The fact that the plate current is so much greater than the grid volt- age would warrant, shows that the vacuum tube is acting as an amplifier. This is a valuable property, one which makes the vacuum tube successful in its application to radio. The same prop- erty, by a slight alteration of the cir- cuit, may be used to make a vacuum tube and an efficient detector. The use of the amplifying property is familiar in the construction of numer- ous two-stage amplifiers now on the market. Amplifications of many hun- dreds and, frequently, thousands of times are possible. The plate current is sufficient to operate a pair of tele- phones, or ear pieces. (Photo by Paul Thompson) The 5-watt Transmitting Tube now the United States Navy. Digitized by Google

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RADIO WORLD 9 Radio Big Help to Airship C-2 on Western Trip WASHINGTON, D. C— Radio aided the United States Army airship C-2, on the westward leg of her transcontinental trip. Dur- ing the sixty-hour cruise, hundreds of miles of which were traversed in dark- ness, radio was always available to lend a guiding hand when any doubt as to the position of the airship existed on what was the first transcontinental airship cruise. All Army airships and airplanes are equipped with the latest radio ap- paratus. In many instances, radio has informed the pilots as to location, course, or weather. In the event of an accident or trouble, it has been the means of bringing aid. The first thousand miles of the west- ern trip was made in approximately twenty hours, flying time, Major Strauss, the commander, reported from Belleville, Illinois. All along her west- ward route from Norfolk over Akron, Belleville, Fort Sill, San Antonio, El Paso, Yuma, to Arcadia, California, Captain G. A. McEntire, the radio of- ficer, kept in touch with Army, weather bureau, and private radio stations which advised him regarding the me- teorological conditions to the westward. Radio will again guide C-2 on her re- turn trip to Langley Field, Virginia, this week. The radio equipment of the C-2 con- sists of a modified SCR-67-A radio telephone and telegraph vacuum-tube set, with a sending radius of about ten miles for the phone circuit and forty miles for the telegraph. The trans- mitting wave used was 480 metres, but messages on nearly all wave lengths were receivable. In the present in- stallation batteries are used in sending, but the radio experts of the Army Air Service have been experimenting on a generator geared to one of the driving engines, which will give these radio sets more power. The antenna is a single wire trailed below the airship and is about 100 feet in length. The C-2 will remain at Ross Field for several days in order to afford her crew a needed rest and give the people on the Pacific Coast an opportunity to witness several exhib:tion flights. After some slight overhauling she will return to Langley Field over the same route, Major General Patrick, chief of fhe Army Air Service, stated a few days ago. This transcontinental flight was intended merely to point the way for flights across this route for larger airships. The southern route was By Carl H. Butman chosen because hangar facilities and landing crews were available at the several stations en route. Arrangements were made whereby most of the flight of the C-2 across the United States was done at night. Airships are in their element in night flying, as atmospheric conditions are much calmer than during the day, less hydrogen gas is lost through expansion and better static equilibrium is main- tained. Night flying in airships is a reasonably safe proposition, for even should motor trouble develop, repairs can be made while the ship is drifting in the air, no forced landing being necessary. It was during the night trips that the radio equipment proved most valuable as well as a means of entertaining the crew, who frequently listened in to radio concerts while en route. M. R. Brennan, Superintendent of the N. Y. Police Telegraph Bureau at WL A W Station (C. International Nw of the New Yerk Potto I Suaortatenlmt af Ike Folic* Th* interior of the ranfe In I mdr ■ ■ Hiig-atohan aeelgned Ike call latter*. WLAW. M Bureau, BJ photographed at tk* traaa Tha Ml— t currant-control of lighting tka fUaaaaate U Tha modulation lyitm need wttfc tkia • > tka hlgheet efBcimwy la clearly modulation. la tkia photograph tk* haa ■aittmg gear I* at tk* riant, la batter known aa tk* paaol-coatral board. On tkia board aU adhiataaarta af pmmm i mad*. Tha born la a Woo torn Elactrtc power aanpUflor-natt, uaad aa a laud-soaker hi oa ncctian with tha receiving art. To tha loft of Iho bora la tha receiving art. Tha Htti* i abject lying on tha table la tka tranemittor. Thraufh due the breedcaetiag la otartad. ThU transmitter, in turn, eeada the epoken worn* to the aai tranaenlttar, where the vacuum tube* perform the nececaary work. To obtain the boot reeulte, the magnitude of the feeble current* produced by the microphone must be mcreeaed many times before they are Im- proeaed on the radio transmitter. For thia purpoae, aa Input amplifier provldeo the netoo eery amplification. Thle consists of a three-etage aaapUner eo mounted thet all the centrele of the amplifier are ecceeaible. Current to operate the microphone ie supplied by aa U-vert storage battery and ie- regulated by a rheoatat on the Input-amplifier panel. Digttfzed by Google

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10 RADIO WORLD The Passing of Poldhu— MBD Famous Cornwall Station where Marconi First Used Transatlantic Radio Had a Romantic History By Arthur G. Shirt AS science progresses, instru- ment after instrument go their silent way to the junk-heap, forgotten by all except a few, whose duty it is to classify and preserve the remembrance of radio gear that has come and gone. There is little or no sentiment at- tached to this process. Like obso- lete theories, the wireless antiques are of no interest. On the other hand, when a unit of a great sys- tem of communication passes into the discard, such as the famous MBD, at Poldhu, Cornwall, Wales, it is only too proper that due re- spect should be paid to its memory. Poldhu, now abandoned in favor of> the station at Clifden, Ireland, has played its part in the building up of the immense world-circling Mar- coni system of radio communica- tion. It has stood the test, and from the night of December 12, 1901, when the first weak signals were pushed across the Atlantic to the day, in September, 1922, when the station was closed to traffic, Poldhu has maintained its end of the sys- tem. The story of the first transatlan- tic signals weaves itself around the Poldhu station. Marconi was in England at the time, conducting experiments before the officials of the postoffice department, and dem- onstrating, with the rapidly in- creasing range of his crude instru- ments, that the limit of radio sig- nalling was practically unlimited. But men who called themselves practical — men opposed to Marconi, who was supposed to be visionary, — said that the curvature of the earth would prevent transmission to any great distance. They were Radio Set Just Fits Man's Hand (a Underwood * Underwood. N. T.> So many amateur* tiara baan Baking miniature radlo-eets that wa ara shewing In ths accompanying illustration an unusually small one. It fits Into tba palm af the hand. Thar* that it works but bo racorda art daimad for receiving long dlatanca with it. BssnamhsT ifs only • miniature set. but It judging the capabilities of this new force which follows the contour of the earth by the conduct of other systems of signalling, such as the heliograph and other sight devices. Marconi, not as well acquainted with wireless phenomena then as he is to-day, thought differently; but up to that time, the distances covered proved neither one thing nor the other. Naturally he was particularly anxious to establish transatlantic records, so that for once and all this question of limit- ing the scope of radio waves should be settled. For him, it meant a matter of gaining the backing of those who withheld their valued support unless this particular con- troversy was cleared up. So eager was Marconi to prove that curvature of the earth would not interfere with the progress of electromagnetic waves, that he started on the station at Poldhu at a time when his instruments had accomplished the record of only thirty-six miles ! What greater tri- bute could there be to Marconi's faith in the possibility of his inven- tion? At the same time, a similar high-powered station was com- menced on Cape Cod, which was to be the American side of the great test. Marconi knew that to pro- duce electro-magnetic waves of a force sufficient to bridge the Atlan- tic, he must have instruments far in advance of what he then pos- sessed. He couldn't have instru- ments that differed to any great ex- tent, for what he had already evolved represented the peak of radio progress ; but he could and he would have them larger and more powerful in every respect. So the layout of the station at Poldhu, as it was when the signals were hurled across the Atlantic, were no differ- ent in theory than the amateur spark-coil outfit of to-day, with a transformer, condenser, and induct- ance coil. But there was a genera- ting plant consisting of an alterna- tor capable of an output of about twenty kilowatts, which through suitable transformers, charged a condenser having a glass dielectric of great strength. The aerial at Poldhu consisted of fifty almost vertical wires, arranged in the vertical fan style, and sup- ported at the upper end by a wire Digitized by Google

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RADIO WORLD 11 (Continued front preceding page) stretched between two masts. The masts were 150 feet high, and 200 feet apart. As first erected, they were not strong enough to with- stand the gales of a Cornwall win- ter, and on September 18, 1901, were blown down during a raging storm. Work was again started imme- diately, in an endeavor to have the Poldhu station and the Cape Cod station ready at about the same time. But a further delay came in the form of a storm on the Ameri- can coast, which wrecked the masts at Cape Cod. This was in Novem- ber of the same fatal year, and Mar- coni's discouragement was ex- treme. But with a determination that characterized his actions from the very start, he completed the reconstruction work at Poldhu, and then journeyed across the Atlantic" with a few assistants and a make- shift receiving set, which he in- stalled in a rough building on the cold shore of St. John's, Newfound- land. He could build no masts, and so sent his aerial aloft by the means of kites, which made the stupendous task he was then en- gaged in doubly hard. The varia- tion of the wind produced constant changes in the angle and the alti- tude of the aerial, so that capacity and period of electrical resonance was never the same, making it al- most impossible for Marconi, tun- ing with the temporary instruments below, to remain on any one wave length for any period of time. On the night of December 11, all was ready. The operators at Poldhu had been instructed to begin send- ing the test signal — which was the three dots of the letter S— on and after December 11, keeping a steady transmission of that letter for ten minutes and then resting five minutes. When Marconi first listened in at the appointed time, he knew that so far as it was possible to depend on human co-operation, that Poldhu was working and periodically directing her signals towards the anxious inventor in Newfoundland. Across the ocean! Could it be done? Some of the greatest scientists in the world had said that the feat was impossible! But as in the case of the amateur trials, just twenty years later, the momentary failure was no indica- tion of what was to follow. Mar- coni listened all the night of the 11th, and heard nothing. The day of the 12th was spent in correcting the receiving instruments so that they responded to Marconi's ideas as to what should obviate last night's difficulties, and in the eve- ning of the 12th, to the overjoy- ment of Marconi, the monotone sig- nals from Poldhu station were An Amateur, to Get a License, Must Read Ten Words a Minute (Republished by General Request) INTERNATIONAL MORSE CODE AND CONVENTIONAL SIGNALS L A daafa la eqeel b> three dot*. & The apace betweea parta ol tae i 3. Tfcei » letter laeeaal to ana dot. 4. Tina • between two letter* U eqaal to three mm. A A e aaa B aaa • e e C_._. Period _ Da... B e - e aaa e mm e aaa Fee aaa • Colon H e e e e lee Br I* • Hi • • M mmm9 Hnoea Neil - ~ — w w ^ m Bar indicating fraeti - aaa e e ana e r e aaa ana e Steii Iarated commas _ . . . S e e e Tana Oeeaaa Tutsi Doable dash W • BBS SB Distress Cal ■ mm e e e mm ■ • e e ana aaa aaaeee tea.*. Tbiibibi Attention call to pret ede ever/ tr Z — _. . General Inquiry call X (German) ■ aaBeaaae SBaaaaeaaB a. a . • t a j. » » A or A (SpuoMoadiuria) From (de) aaa e e • e mm mm e mm Imitation to transml t (go ahead) aaa e mm CH (German-Spanish) E (FVench) e e mm e e R (Spanish) aaa mm e mm mm Warning -high poire ana ana e e ana aaa e e aaa aaa e e Question (please rep ranting long mean, ...)-intor- 5 (German) Wait e aaa e e e 0 (German) • • mm mm Break (Bit.) (double dash) aaa e e e aaa Understand e e e aaa e eeeeeeee 3 e e e mm mm 4 e e e e mm 6 mm e • e e Position report (to precede aO pa eitioa mea- e aaa e ?saasaaeee aaa e aaa e End of each message (cross) Transmission finished (end of work) (conclu- sion of correspondence) • aaa e aaa e e e e aaa e aaa heard in Newfoundland. They were faint, of course—dot, dot, dot # #, dot, dot, dot # with a few omis- sions when the wind got to play- ing havoc with the fixed capacities of the aerial system. But they were signals! The impossible had been achieved! The Atlantic had been bridged! That accomplished, Mar- coni could bid for all the support in the world, confident that the radio waves he employed were capable of something revolutionary in the way of communication. Such is the story of Poldhu— of its building and of its mission. From that day, when its fan aerial was the object of much wonder and speculation, to this, when its ar- rangements are antedated and its presence in the chain of Marconi stations no longer needed, it has made wireless history. Now it passes forever from our view. Digitized by Google

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12 RADIO WORLD The Radio Primer A Weekly A. B. C. of Radio for the Beginner, in which Elementary Facts and Principles Are Fully and Tersely Explained and all Words and Terms Used by Amateurs and Experts Defined fTTHAT is a circuit? What are ylr the different parts and what do they represent? Are all, circuits illustrated alike? The accompanying circuit is a good example. It shows the tuner up to but not including the detector circuit. It is a desirable circuit for tube detectors. It is a circuit which may be found in any form of publication. A is the aerial; B the primary switch-handle. C is the tapped primary of the primary Schematic diagram showing the tapped primary and the secondary of any Ioom- coupler or varlo- eoapler. Whenever this diagram 1* shown H represent* the parte explained herewith. coil marked D. E is the secondary coil. F shows how the coupling of the magnetic waves are induced into the secondary. G is the ground con- nection. H is the variable condenser in shunt to the secondary of the tuner. I is the grid condenser. J is the grid leak. Usually the grid condenser and leak come together. The grid leak is drawn in either position as shown in the diagram by letter J. * * * How can the primary winding of a loose coupler, or vario-coupler, be de- termined when using a "variable con- denser? When drawn in a circuit does it always appear this way? A schematic diagram is herewith published with the variable condenser in series with the primary of the vario- coupler, or loose coupler. This is often termed a tuned circuit. The in- ductance of the coil is varied by cut- ting in or out of the circuit a number of turns of wire at a time. The variable condenser consists of two sets of plates — one being stationary and the By Lynn Brooks other movable. By rotating the plates, we vary the electrical capacity of the condenser. This tuned circuit will re- ThU diagram shows the variable contact on the primary which makes it possible to increase or decrease inductance la the primary circuit. A variable condenser la also meet tod m series with this primary inductance. spond to a number of wave lengths at the same time; or, in other words, it will tune broadly. * * * Is there any other method used that will answer the purpose of the slider principle? J-. This has been overcome by making taps on the winding. Wires are soldered on these taps and then brought out to the front of the panel on switch points and a switch handle. The ac- A tapped primary is illustrated in this It may be seen that If the switch handle la moved, inductance of that coll will be Increased or decreased according to the way it la moved. companying sketch shows how the taps are brought from the primary wind- ing to the handle. * * * In using a vario-coupler, or loose coupler, with a variable condenser in shunt to the primary, how should this appear in a diagram? Does it look the same in every illustration? When using a vario-coupler, or loose coupler, where two windings are em- ployed— such as primary and secondary — the accompanying sketch will show how it is always illustrated. Here the secondary is in shunt to the primary winding, while the arrow shows that the coupler is variable to the principle it placed m shunt to the When this diagram appears of the loose The arrow drawn through the primary leans that of coupling. The secondary coil is usually arranged so that the magnetic field may occupy the same space as the field of the primary coil, or may be varied in position so that it occupies only a part, or none, of the same space. This is called the varying of the coupling between the coils. A is the aerial. B is the primary-coil tap. C is the primary coil. F is the secondary coil. H is the primary condenser in shunt. E is the coupling. D, ground. In summing up in regard to the diagrams published on this page, symbols are drawn the same in all circuits no matter where such cir- cuits are printed. I would advise every radio amateur or experimenter unfamiliar with such diagrams, or symbols, to study them carefully so that he may readily and easily un- derstand any hook-ups that may apr pear in radio literature. Digitized by Google

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RADIO WORLD 13. Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengths for the Busy Reader. RADIO will be one of the most efficient means of capturing fugitive criminals, says Richard E. Enright, police com- missioner of New York City. Mr. Enright made this im- portant statement in an address before the conference of American and Foreign Police Chiefs last week. He added that in a year's time most of his department's out-of-town business will be carried on by radio. In a few years, the police of all parts of America will be in touch by radio, making it possible to co-operate in the apprehension of criminals on a scale here- tofore impossible. The days of the guilty are numbered. » » * An average of 2,500 radio messages a day are handled during each five-day trip across the Atlantic, by the radio operators of the Cunarder "Majestic." * * * Under the auspices of the Australian government another very large radio station is to be erected near Sydney, its cost to be more than $5,000,000 and its operation to be conducted by the Amalgamated Wireless, an organization springing from the Marconi Wireless Telegraph Company. * * * Sweden awarded the contract for equipping her new power- ful radio station, to be erected forty miles south of Gothen- burg, to the Radio Corporation of America in spite of a lower bid from the German Telefunkcn Company. The reason was that the American company offered better terms of payment. Quotations Received by Radio! (C. Kadel A Herbert News Berries.) in Wall Street is the very latest innovation for the radiophone, photograph show* the interior of a prominent Wall Street to receive stock quotations and cur- The amount of the equipment contract is $432,500, one-third cash and the balance from future receipts without interest charges. The total cost of the^ station will be about $1,300,000. The first American singer to have his voice broadcast by European radio telephones is Charles Hubbard, a tenor born in Auburn, N. Y. He sent out several numbers from the Eiffel Tower station which has a wave length of 1760 meters. * * * The Virgin Islands will install radio apparatus for broad- casting official information and entertainment, according to Adolph Sixto, delegate from St. Thomas. Recently he visited Washington officially, and called at the White House, where he told the reporters that, as a member of the Manufacturers' Commercial Association of the Islands, he was hoping to in- troduce radio broadcasting as soon as suitable equipment could be secured for sending and receiving. * » * Rear Admiral H. J. Zeigemeier, director of Naval Communi- cations, who has been designated to represent the Navy at the First Pan-Pacific Commercial Conference, at Honolulu, October 25 to 31, will speak there on communication and transporta- tion, giving special attention to a survey of the present cable and radio activities. He will discuss the establishment of lower special rates, fixing responsibility and granting improved fa- cilities for the press. * * * New vacuum-tube transmitters are being installed on the submarines of the U. S. Navy. Tests on submarines have been very satisfactory, according to naval experts. The set makes use of equipment already in the hands of the Navy, with some additional material necessary to modernize it. Tests show daytime ranges of from 150 to 250 miles while a submarine was on the surface. It is claimed by experts that it is possible for the submarine to operate its radio while submerged. * * » WLAW, broadcasting station of the New York City Police Department, although in operation less than two weeks, has been reported from points in New Jersey as coming in so strong and clear-cut that its modulation is a distinct improve- ment over other stations in the metropolitan district. * * * Three other cities besides New York are applying ras&o extensively to aid their police systems in suppressing crime. They are Denver, Col; Dayton, Ohio; and Chicago. * * * When William Gibbs McAdoo, former Secretary of the Treasury, and a party of his friends, including George E Hill, of Rtgby, Idaho, electrical dealer, started down the Snake River on a fishing and hunting trip, recently, the raft on which they were carried was equipped with a Crosley Harko Senior and two-step amplifier, used in connection with a loud-speaker. Mr. McAdoo is an ard nt radio fan, and has expressed » de- termination to take a receiving set with him every time he enters territory in which there are no facilities of obtaining news. * * • Just over the crest of the Kaiser Range in the High Sierras, at an altitude of nearly 10,000 feet, the Southern California Edi- son Company is operating three continuous-wave radio stations at the highest altitude in which radio communication ever has been installed. Radio communication is being used by the com- pany for the direction of practically all the construction work under way by its tunnel workers, who are a part of an army of 4,500 employees engaged in the company's enormous water power electric development in the mountains of Northeastern Fresno County, on what is known as their Big Creek-San Joaquin River development program, which will bring into service 125,000 horsepower of new electric energy next year. * * » The Troy Polytechnic broadcasting station was made pos- sible through a large gift from Washington A. Roebling, the late Charles G. Roebling, and John A. Roebling, of the John A Roebling Sons' Company, Trenton, New Jersey, all graduates of the Institute and famous as the builders of the Brooklyn Bridge. The equipment was installed during the summer months under the supervision of the professors and instructors of the Department of Electrical Engineering, in the Russell Sage Laboratory, erected in 1906 with a part of the million- dollar gift from Mrs. Russell Sage in memory of her husband, who was one of the Trustees of the Institute. Digitized by Google

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14 RADIO WORLD After the Tornado — Something Was Saved! Cartoon by L. B. Hinckley Radio Bu»- "Whoop*! neighbor. I claim I'm the original lucky fujr. Look! It never touched my radio sett* Latest Important Radio News THE Federal Telegraph Company of Delaware le eoon to be launched to take over the tU.OM.M* contract with the Chinese govern- ment, recently secured by the Federal Telegraph Company of California. Owen D. Young, presi- dent of the General Electric Company, will be chairman of the board, and R. P. Schwerin, head of the California corporation, will be president. The new company will be capital! ed at St,5M,Mt, divided Into S3.SM.Ms preferred stock and $*,- MMM common. Profits from the Chinese con- tract are estimated at fs.SM.0M, in addition to a percentage of the net earnings of the stations for a long term of years. Notice of a It per cent, increase In wages, ef- fective October 1, has been posted in all the larger copper mining camps in Arizona. Companies granting the Increase include the Phelps Dodge Corporation, the Calumet A Arizona, Miami Cop- per, Inspiration, Old Dominion, New Cornells, United Verde, Ray Consolidated and others. This increase is due very largely to the demand being made by radio manufacturers for copper, see A prominent radio manufacturer notifies us that, according to his estimate, over one hundred million dollars' worth of radio apparatus will be sold this winter. e e • United States Government experts report that high frequency waves from radio broadcasting stations hare caused vegetation to take on a larger growth and reach maturity sooner than under ordinary conditions. • • e Lea de Forest, the eminent radiotrician, arrived from Europe on the "Berengaria," laet week. He brought with him his latest radio Invention, the phonofilm, by which he will reproduce speech in moving pictures. • • * Radio has been utilized to Intercept rum run- ners on the high seas. According to the "Times,'' New York, a ship ostensibly bound from New York for Greece waa halted by the authorities after radio bad notified them of her position and cargo. e e * The aerial for the new broadcasting station on the Municipal Building, New York, Is In place. • • • American radio exports during Jury totaled 22S.47S pounds of apparatus, valued at SMS, Ml, which shows that some American exporters are taking advantage of trade opportunities. Radio Success in Bahamas About a year ago, the Bahaman Govern- ment purchased three radio transmitting sets from the United States Shipping Board and put them in operation with such suc- cessful results that three more sets have been purchased for inter-island communica- tion. The equipment is of the 1-kw spark type such as is used on Shipping Board ves- sels. It gives excellent communication be- tween the islands of the group. 13 More Broadcasters THIRTEEN limited commercial broad- casting stations were licensed by the Department of Commerce during the week ending September 16, us follows: WLAN — Putnam Hardware Co., Houl- ton, Mo. WMAF — Round Hills Radio Corp, Dart- mouth. Mass. KFCD — Salom Electric Co., Salom, Ore- gon. WEAN— Shepard Co., Providence, R. 1, WNAC — Shepard Stores. Boston. Mass. WLAQ— A. E. Shilling. Kalamazoo, Mich. WOAI — Southern Equipment Co, San Antonio. Tex. W LA K— Vermont Farm Machine Cov, Bellows Falls, Vt WLAT— Charles G. Bosch Co., Burling- ton, Iowa. WLAP— W. V. Jordon, Louisville, Ky. WLAR— Mickel Music Co, Marshall- town, Iowa. WMAC— F. Edward Page, Fernwood, Cazonovia, N. Y. WGAX— Radio Electric Co, Washington Court House, Ohio. Don't Miu This! (Radio World, Vol. I, No. 2, dated October 7, will contain a complete) Hat, alphabetically arranged, of every broad* casting station in this country up to the) day of going to press. Be sure to get sz copy of Radio World, containing this list, as you will need it during the fall and winter months.) Digitized by GooqI

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RADIO WORLD 15 Radio and the Woman By Crystal D. Tector tt\/f Y Dear Crystal," writes a girlhood friend who has V I iust marr'ed> "we — that is, John and I — have de- A cided to live in the country. Of course, he had to give in to my whim to have my home where I want it. He dearly loves the big town, I know, and has terrible hankering for his club and all that sort of thing; but I do cherish a little home in the suburbs and all that goes with it. It does seem so cuddly and dear — and he will have to be home every night. But I could not let my selfishness run away with everything, and John finally capitulated provided I would let him install a radio set He says it will be a nice thing which to enter- tain the neighbors. Now, what is a radio set?" * • • Poor misguided thing. I won't betray her by even mention- ing her first name; but to imagine that there is even a woman in all this world who' does not know what a radio set is I It seems absolutely preposterous. What, my Radio. World read- ers, do you think I did by way of reply to such a letter- even if it was from an old and very dear friend? Well, I had the impertinence to tell her that if she would buy a copy of this issue of Radio World, she would find her answer in my department. It just took her off her feet, and she phoned me hoping that I wouldn't write anything to make John angry. * * * My Dear Mrs. Newlywed — and all others who may be in your state of ignorance— a radio set is just about the one thing that will make your home, especially if it be in the country a perfect haven of joy. Friend Husband and I are commuters — that is, we belong to the vast army of the Ameri- can citizenry who live a suburban life and come to the city just every so often for our pleasure; but we do notice that whenever we invite any of our big-town friends to visit us, their faces beam with more than customary satisfaction. We were among the first to take up radio. It seemed a heap of trouble and looked like a terrible expense; but we have been more than repaid; in fact, we said, the other night, after list- ening to one of the most wonderful concerts that I ever heard —the music coming in clear and distinct and absolutely with- out a blemish— that we would not be without our set for more than a thousand times what it has cost us. And the expense hasn't been so very much at that. * * * To tell the gospel truth, I would rather have a radio set than a motor-car any day in the week. It affords more keen and honest enjoyment— and it is such an unselfish pleasure I The satisfaction that one gets in entertaining one's friends — and in a manner so absolutely original and fascinating! Why, the other night, we actually heard an entire play— "The Wolf," by Eugene Walter— broadcast from Schenectady. The man- ner in which it was explained and the clearness in which the lines were spoken and the action brought out, made it a fea- ture of more than ordinary interest. Some of my friends tell me that I am too much of an enthusiast— that I let my happi- ness run away with me— but I just want to tell you that if the drama can be broadcast so entertainingly as this play, very few trips to New York will F. H. and I make to take in the theatre. * * * But speaking of the city, I did notice the last time I was on The Avenue— as all good New Yorkers term their famous Fifth Avenue— that several of the better-class tea shops were equipped with radio sets. And I was told that with the new arrangement regarding broadcasting it is very easy to tune in whenever anything particularly interesting is on the ether. In this way, one need not listen to everything that is being broadcast For instance, there is nothing particularly inter- esting in a lot of women sitting around tea tables hearing the latest market quotations or the weather reports; but if a good concert or some vocal music or health talks are in the air why it is an easy matter to tune in and catch them. * * • And I do feel that the broadcasters would do well to broaden their programs for the women, particularly during the day- time. So much is being done for the farmer— and we all recognize his great and important place in the course of events— but we women should not be overlooked. I would suggest more easy-to-make recipes. Every woman is inter- ested m her kitchen whether she has one or not. I think too. that practical advice on washing fine lingerie would not be amiss; for few women, to-day, will trust that part of their wardroba to the laundry. Domestic science is good in small doses, particularly if it is practical. Rich or poor, we women are all alike so far as our households are concerned. We want to be told how to keep them in order. And just now, I wish some clever bugologist would radio to me how to get rid of cockroaches! * » * I have received several letters during the past week from mothers who want to know if they can really count on radio to keep their babies quiet. Now I am not so foolish as to say that you can clamp a pair of headphones on a baby's cranium and let the wave lengths do the rest. Many mothers have that idea. Imagine the poor child if an unruly bit of static should jar it. Then, too, baby isn't going to be very much enthused or its teething be made less painless by list- ening to the latest market reports or a sermon. Children are uncertain beings and they must cry and be uneasy during a (C. Central Nmra Bcrrlsa.) "I did notice that Mvtnl of th« bettor-class to with radio acts." goodly part of their young lives. They wouldn't be normal if they didn't. But I do say that many a mother is going to find in radio a very pleasant form of recreation for her little ones. I know that several of my neighbors do not hesitate to leave their babies with me when they want to go to town for a shopping spree— and that these little ones have been sort of quiet and pleased whenever my radio set has been tuned in— and it generally is. * * * Friend Husband told me the other day that he read in "Apartments To Let, Furnished," of one thr^ gav« "-adio" as a modern convenience. That shows what we are coming to. The day is not far distant when every woman who is renting an apartment will examine the radio set as closely as she ex- amines the kitchen. * * * Mrs. Hattie Kolb, of Chicago, writes me that she is study- ing the science of radio in the hope of taking a position as radio instructress in one of the Chicago public schools. She says that, in her city, radio will soon be a part of the public- school courses. Teachers will be wanted and she will be a pioneer in the field. Digitized by Google

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16 RADIO WORLD WBAY to Serve a Commercial Purpose with Radio Toll Station By Golda M. Goldman Photo by Morris Rosenfeld, New York. The American Telephone and Telegraph Company'* Building, Walker Street, New York City, the home of WBAY. The building ie 35» feet high, and the antenna la IN feet above the roof. THE commercial uses to which the radiophone is being put are far removed from the knowl- edge of the amateur. Only he who possesses a set beyond the average is in touch with the manifold ways in which the radio is serving the business world. And now comes the latest de- velopment in the commercialization of this power. The American Telephone and Telegraph Company is presenting New York City with a radio toll-sta- tion, known by the call number, WBAY. While mechanically inclined radioists for years have been contriving receiv- ing sets and snatching messages in code out of the air, it is really only within the year that the perfecting and popu- larizing of radio broadcasting has swept the country with a wave of in- terest. Broadcasting stations ap- peared almost simultaneously in many of the principal cities, and every dealer whose business was in need of expansion or new blood im- ■ mediately stocked in radio accesso- ries and did a thriving business. The result, as all fans know, was that Herbert R. Hoover, Secretary of Com- merce, found it necessary to call a conference of radio experts who made recommendations of proper wave- lengths to be used for various purposes, so that, today, most stations are work- ing on a 360 wave-length. This necessitates a schedule to which all broadcasting stations in one vicinity must adhere, only one operating at a time, and so avoiding confusion. When it became evident that the pub- lic had become even more interested listening-in than in reading anything except the radio page in the papers, big business men began to consider it as a tremendous possibility for advertis- ing, and the American Telephone and Telegraph Company could have in- stalled over one hundred broadcasting stations in New York's business sec- tion alone. The difficulty was that these merchants knew nothing of con- flicting wave-lengths, of government regulations, or of the fact that, after installing a station at tremendous cost, they would be able to use it only a few minutes each week. Therefore, as one of the officials put it, "It would have been like taking money from a baby," these stations were never built. In- stead, The American Telephone and Telegraph Company decided to ex- tend its own "leased facilities" busi- ness, by which private wires for banks, newspapers, etc., are ar- ranged, and so built one of the finest stations now operating, which it plans to rent to advertisers for a quarter or a half hour at a time, much as they might pay for a telephone call. The public has, however, been edu- cated up to a high standard of broad- casted material, and there is no inten- tion of lowering these standards through the manner of presenting the advertised commodity. John Doe, real estate broker, is not expected to an- nounce merely that there will be a sale of particularly fine lots on the following day, with details concerning their desirability. The number of fans who would listen for any length of time to any crudities of the sort would be decidedly limited. Instead it is intended that all matter shall be Digitized byGoOQlC

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RADIO WORLD 17 (Continued from preceding page.) presented in artistic form, through speeches on allied subjects, the adver- tising to be subtle and indirect. A life-insurance company, for instance, rather than send out a stereotyped list of benefits to be derived from a policy, will send one of its skilled physicians to give a health talk. It will mean merely this: At present the purpose behind most broadcasting is to enter- tain the unseen audience to such an ex- tent that it will buy new improvements for its outfit, and stimulate friends to buy, which is of course advertising in itself. So are the present programs advertisements for the artists and lecturers, which in no wise detracts from the value of the donated services. Primarily the present stations em- phasize entertainment, with the adver- tising incidental, while WBAY will only use the entertainment as a means for much valuable advertising. At present the operation of this plan is held up by the limited number of wave-lengths legally permitted, and the schedule of hours in operation. Re- lief is expected from two bills now in Congress requesting broader powers for the Department of Commerce, and through the department an increase in die number of wave-lengths available. As most amateur sets will cover quite a wide band of lengths, it would then be possible for more than one station to operate at the same time. With the press of business before Congress, it may be months before this new de- parture will be inaugurated. Mean- while, WBAY sends out the afternoon and Thursday evening programs which it started on August 3., and continues to experiment with and perfect its ap- paratus. There are many features of this ap- paratus in the new station which are of note. In the first place, the studio itself has been so skillfully built and arranged that it is echoless. Felt padding on the walls and parts of the ceiling assists in giving to all voices the effect of a clearer enunciation. A second advance in technical apparatus is to be found in the microphone, or transmitter, which like all the rest of the electrical equipment was designed and manufactured by the Western Electric Company. It is so perfected that it is no longer necessary for the speaker or singer to limit his move- ments to such positions as will bring him close to the transmitter. This gives him the opportunity to exercise all the freedom of action which is so essential a part of a finished entertain- ment. Two of the World's Greatest Radio Towers A photograph of the interior of the operating room of WBAY, with a complete description of all the im- portant parts of the apparatus, by our technical editor, will be found on the front cover of this issue. (C. Underwood & Underwood, New York) Tho famous station at Arlington, Va. The towers are 45* fet high. r.m ■ •■/ - ' ' 3 a A [ N 1 > 9 ' "" il B mBBEJpj™ M aaMssnanM li asBBOB (C. International News Reel Photo) Center of Germany's radio: The new powerful station at Oranienburgarstr Digitized by ' Google

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18 RADIO WORLD Answers to Readers Amplifying Grid Ledk Transformer, (wiJ££)-Grid Condenser ,6 Schematic diagram reqoeated by Mr. William Lane St- Look. j~\ LEASE publish a hook-up showing tht r' necessary connections when using a * vario-coupler and one stage of ampli- fication of the straight amplifying-type re- ceiving set. — William Lang, St. Louis. The accompanying diagram shows the proper hook-up for the straight-type ampli- fying receiver. It will be noticed that the grid condenser and leak are inserted in the grid of the amplifying tube, however, we suggest that it be placed in the grid circuit of the detector tube for better results. Sometimes it is more of an experiment; therefore, we advise the experimenter to try out the grid condenser in the tube of the detector circuit. » * » Do the radio-frequency amplifiers increase the range of a set. Do loop aerials work best with such amplifiers? — Albert Murphy, Roscdale, L. I. Radio-frequency transformers are made to increase the range of a receiving set They are placed prior to the detector tube and amplify the original frequency-wave be- fore it reaches the detector. Loop aerials are used almost exclusively in order that most of the unwanted noises may be elim- inated. The loop aerial also has the func- tion of giving directional effect upon the signals desired. * * * I Where can I buy plans to build the superregeneralor receiving-set invented by Major Edwin H. Armstrong T I have a regenerative set and am getting good re- sults. I would be gratified if I could see a description of the circuit and how it is assembled.— S. A.' Masters, Lakeland, Fla. A full description of the Armstrong superregenerative set was published in Radio World No. 25, dated September 16, in an article entitled "How to Make a Two-Tube Superregenerator," by Frederick J. Rum ford. * » * / have a short-wave regenerative set which I made, as described in Radio World, No. 22. dated August 26, with jacks in each stage. The detector works fine, but when I plug in on the second step, signals are not so loud as the detector. What is the trou- ble f I am using Thordason transformer. — John Kelly, Camden, N. J. Test each tube out separately. In some cases, amateurs connect up incorrectly the secondary of the audio-frequency trans- formers. Make a good check-up of this and experiment awhile until you locate the trouble. Test out each and every part as you go along, from tube to tube. See that the proper plate-voltages are lad, as well as the correct wiring to the tubes and jacks. * * * Will you publish a hook-up for a regen- erative receiver employing honeycomb coils, Ai-plale variable condenser and a variable condenser? Does it matter which binding post you take the lead from in a honeycomb coil?— William J. Kelly, Rockaway Beach, N. Y. Antenna Schematic diagram requested by Mr. William J. Kelly, Rockaway Beach, N. Y, The accompanying is a diagram of the so-called regenerative receiver. This is the honeycomb type. In the above hook-up, it is very easy to discern where the honeycombs are placed. V C is a variable condenser of 43 plates. P is the primary, S is the sec- ondary and T the tickler. The rest of the circuit is self-explanatory. Either binding post may be connected from the honeycomb to such connections as needed. * * * What do you consider the best hook-up for a crystal sett My set consists of a two- slide tuning coil, one detector, one conden- ser and a set of 3000-ohm phones. I have seen and tried various hookups, but nons seem to work. — Norman Blankenship, Cash- ing, Okla. Radio World No. 11. dated June 10, in "How to Construct One- and Two-Slide Tuners." by George W. May, covers your query fully. * • * What is the rated voltage for the V-T-\ tubes ? — Radio reader. As the writer has had years of experience with these tubes, he considers it most essen- tial that you secure a 6-volt battery. In all cases, the tube will draw approximately from 5 to 6 volts. As amperage is the big factor, these tubes are limited to about 1.25 amperes and. in all cases, should not be allowed to go beyond this rating as it may mean the burning out of the tube. It will be found that the tube will work best when kept at a cherry-red glow. • • * Is there a circuit I could use in which I could hove both a tuned circuit and an un- tuned circuit f If possible I would like to see a hook-up of such a circuit. — James Brandon, Boston. DR0.T. Switch Schematic diagram reqneeted by Brandon, Boa torn. There is such a circuit We have had one drawn, and it is published herewith for your convenience. A double-throw, double- blade switch is used which enables the operator to switch from the untuned circuit to the tuned circuit. It may be said that these principles are used in the Navy type receiver, used both on battleships and in land stations. The idea is to keep the switch placed in — on the untuned cricuit— which has a coil about the primary wind- ing. This makes it possible to allow signals of a broad interfering-wave possible. If the operator wishes to eliminate interfer- ence in order to read some distant station he will then throw the switch over to the tuned circuit and start tuning in the desired station. This will make a valuable circuit for such work, especially where a close watch is to be kept on everything that is transmitted. Radio Club Starts School A RADIO school four nights a week will be conducted this fall by the Hudson City Radio Club, of Jersey City. Code will be the first thing taught be- cause, says the secretary, "a lot of people don't know what they are missing. Don't holler about the ham with his spark and write to the radio inspector when it is some ship on WNY or NAH or some The Hudson City Radio Gub was organized in April, 1920, and incorpor- ated in August. 1921, with thirty-six members. It aims to have at least 136 during the coming year. Anyone inter- ested should write to H. A. Bremer, No. 89-91 Franklin street, Jersey City, N. J Digitizechby Google

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RADIO WORLD 19 Civil Service Examination for Junior Radio Engineer For Men and Women — Opens October 10, 1922 THE United States Civil Service Com- mission announces an open compe- titive examination for junior radio engineer on October 4, 1922, at which ex- amination is requested in applications received in time to mail examination papers. Vacancies in the Signal Service at Large, Camp Alfred Vail. N. J.; it va- cancy in the position of radio laboratory assistant, Fairfield Air Intermediate De- pot, Fairfield, Ohio, and vacancies in po- sitions requiring similar qualifications at Washington, D. C, or elsewhere iu the United States, at $1,200 to $2,000 a year, jr higher or lower salaries, will be filled 'rom this examination unless it is found n the interest of the service to fill any acancy by reinstatement, transfer, or romotion. At the Commission has had consider- U« difficulty in securing sufficient elig- le* for this position, qualified persona • org ad to oator this examination. Rang* m salary—- The entrance salary thin the range stated will depend upon e qualifications of the appointee as jwn in the examination and the duty which assigned. lonnaw— Appointees whose services are isfactory may be allowed the increase nted by Congress of $20 a month, ertification.— In filling vacancies in po- ms with headquarters outside of shington, D. C, certification will be e of the highest eligibles examined est the vicinity of the place at which appointee will be employed except upon the request of the department fication will be made of the highest iles on the register for the tt.tire :ry who have expressed willingness cept appointment where the vacancy sen ship and sex. — All citizens of the d States who meet the require- , both men and women, may enter examination; appointing officers, er, have the legal right to specify k desired in requesting certification iblea. m. — The duties of the appointee to assist in the development, de- id construction of practical and radio apparatus, and other related eta and weights.— Competitors will I on the following subjects, which e the relative weights indicated: Subjects. Weights eral physics 20 hematics through calculus 25 rtical questions on radio gineeringr 30 ration, training, and ex- •ience 25 tal 100 ale>. — Competitors should pro- selves with a slide rule; in case allowed it will be so stated in nation sheet. •ry requirement. — The appli- show that he has been gradu- a degree from a college or of recognized standing with etion of at least 118 credit •hat he is a senior student in ttitution and furnish proof of luation within three nonths ate of the examination. The ust show that his undcrgrpdu- i eluded a course in electrical engineering, and also the usual college course in general physics, general chem- istry, and mathematics through calculus. Special credit will be given for experi- ence in a scientific, industrial, or technical laboratory. Statement of college course. — The ap- plicant must submit a statement of courses taken at college signed by the proper authority of the college or univer- sity attended, and give a detailed record of his technical experience and have the vouchers filled out by men professionally qualified to vouch for his ability, fitness, and personality. Age. — Applicants must not have reached their fifty-fifth birthday on the date of examination. This age limit does not ap- ply to persons entitled to preference because of military and naval service. Retirement— -Classified employees who reached the retirement age and have served fifteen years are entitled to re- tirement with an annuity. The retirement age for railway mail clerks is 62 years; for mechanics and post-office clerks and carriers, 65 years, and for others 70 years. A deduction of 2yi per cent, is made from the monthly salary to provide for this annuity, which will be returned to per- sons leaving the service before retire- ment with 4 per cent ijterest compounded annually. Photographs— -Applicants must submit to the examiner on the day of the ex- amination their photographs taken within two years, securely pasted in the space provided on the admission cards sent them after their applications are filed. Proofs or group photographs will not be accepted. Photographs will not be re- turned to applicants. Residence and domicile. — Applicants may be examined at any place at which this examination is held regardless of their place of residence; but only those who have been actually domiciled in the State or Territory in which they reside for at least one year previous to the ex- amination, and who have the county offi- cer's certificate in the application form executed, may become eligible for perma- nent appointment to the apportioned service in Washington, D. C Applications. — Applicants should at once apply for Form 1312, stating the title of the examination desired, to the Civil Service Commission, Washington. D. C, or to the Secretary of the United States Civil Service Board at any place listed hereon. Applications should be properly executed, excluding the medical certifi- cate, and must be filed with the Com- mission at Washington in time to arrange for the examination of the applicant. The exact title of the examination, aa given at the head of this announcement, should be stated in the application form. Preference. — Applicants entitle J to preference should attach to Ike afflicniions their original discharge, or a photostat or certified copy thereof, or their official record of service, which will be returned. There Is Hope! Since large corporations find it profit- able to provide entertainment by mrans of radio for their employees in isolated places, this may also be the solution of keeping the hired girl back on the farm. THOUSANDS of families have only "gone in for wireless" after hearing dem- onstrations of Magna vox Radio — the Reproducer Supreme. It is the Magnavox Radio which gives every receiving set its great- est enjoyment and use— doing away with the restrictions and limitations of the individual headset. The re- ceiving set only brines the message, while Magnavox Radio tells it clearly and in full volume to all within reach of its voice. In perfection of mechanism, quality of manufacture and satisfaction in actual service, Magnavox Radio has absolutely no competition. R-3 Magnavox A Radio with 14-in. horn (here illus- trated), is Ideal for use in homes, offices, etc. Re- quires one ampere held current from your filament bat- tery. Price $45.00 R-2 Magnavox Radio with 18-inch horn for those who wish the utmost in amplifying power; for large au- diences, dance halls, etc Price (ttJO 3- Slag* Xfodcl "C" Magnavox Power Am- plifier insures getting the largest possible power input for your Mag- navox Radio. AC-2-C, 1-Sum . . set m AC-J-C, J SUf. . . nam Our inlerttting new booklet (illuttrattd to 3 colon) mi on nqutti ) THE MAGNAVOX COMPANY Burnt Office and Factory: Oakland, «*-■ Nme York Offie*: S» Savaata Avaaaa

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20 RADIO WORLD Radio Patents Invention Will Locate Distant Transmitting Stations No. 1/127^33. Patented September 5, 1922 Patentee: Frederick S. McCullough, Cleveland, O. THE invention on which Mr. McCul- lough has received letters patent, is important to radiotelegraphy — first, be- cause it will determine the direction of distant transmitting stations; secondly, because it will detect incoming electro- magnetic waves. In the radio directional- systems hitherto used, there have been employed large antennae arranged in cer- tain shapes and directions, and also loops or coils of wire, these coils generally having a number of turns wound on a square frame with the sides several feet, wrnmmwmss Three schematic dU|m showing nans of Mr. McCullough'* system. Figure • ■hows ths flat spiral coil snrlossd in an evacu- or several yards, in length. While direc- tional loops of such size may answer for permanent land-stations, it can be readily seen that theje are grave objections to them for portable stations such as those on a small boat, and more particularly on aircraft. For the latter, it is essential to have the apparatus in as compact form as possible, and by his system, Mr. Mc- Cullough provides means of small size which will satisfactorily determine the direction of transmitting radio stations. Together with his direction finding, he provides for the detection of the incom- ing electrical oscillations. a a a Low-Antenna Signaling No. I.U4MS. Patented August 1, 1922. Patentees: Edward H. Loftin, Wash- ington, D. C, and Henry H. Lyon, Hyattsville, Md. THIS invention relates to radio antenna systems and, more particularly, to sta- tions employing low horizontal antenna or lineal collectors. In a copending ap- plication Serial No. 371,557. filed April 5, 1920, the inventors pointed out the ne- cessity for selecting an optimum length for the horizontal component in such antenna for tuning to obtain the best results on given wave-lengths. The pur- pose of the present invention is the de- vising of a system of antenna for a radio station whereby advantage may be taken with facility and efficiency, of the antenna for general communication with a number of stations employing various wave lengths and having various direc- tions. a a a Electrical Connection to Prevent Shock No. 1,42X429. Patented, July 11, 1922. Patentee: Charles D. Filktns, Schenectady, N. Y. THE object of Mr. Filkins's invention is to provide a reliable means for provid- ing an electrical connection to a movable element in an electrical device which will allow any desired freedom of movement of By this device, Mr. FUldns intends to provide a method oi miilring the con- nections to the movable coil of e variometer which win overcome com- mon disadvantage. the movable element without interfering with the flow of current. In the construction of variable-coupling- devices, or variometers, for use in radio cir- cuits it has been customary to provide a fixed coil and a movable coil which is adapted to rotate with respect to the fixed coil in such a way that the coupling be- tween the two coils may be varied by rotat- ing the movable coil between a position where its plane is parallel with that of the fixed coil and a position where its plane is at right angles to that of the fixed coil. It has been customary in such devices to make electrical connections to the movable coil by means of flexible leads brought from the terminals of the movable coil to fixed term- inals located at some convenient place on the apparatus. This method has the disadvan- tage that it is not possible to rotate the mov- able coil continuously in one direction, and since the leads are usually located out of sight of the operator there is the danger that the operator will attempt to rotate the coil too far in one direction and break the leads. The leads are, also, apt to be broken by the continual bending which is incident to the normal operation of the device. By his invention, Mr. Filkins hopes to provide a method of making the connections to the movable coil of a variometer which will overcome the above-mentioned disad- vantages; also, to provide a means for holding the movable coil in a desired posi- tion and prevent it from moving when die apparatus is subjected to vibrations, a a a To Regulate the Flow of Electric Currents No. 1.42M6S. Patented August 5, 1922. Patentee. Ernest C Daniebon, San Francisco, CaL "VARIABLE resistance is the subject of Mr. Danielson's invention. Primarily it relates to a composition of matter, use- ful for providing an electric resistance device, and more particularly to a vari- able resistance which may be used in a potentiometer. An object of the invention is to provide a variable resistance device of the poten- Figuro 1 is an elevation of Mr. invention mounted on a Figure 2 is a cross section taken on die line 2—2, Figure I. tiometer type in which a metal to metal electrical contact is made between the contact arm and the variable resistance element; to provide a new and useful composition of matter; to provide an in- expensive and reliable resistance element; to provide a simple and inexpensive variable resistance device so constructed (Continued on following page)

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RADIO WORLD 21 Forsaken ! RADIO vest POCKET Caatlatlaa of H> UrtNar. " TOOL SET £cSTP*io H W.EJHC«0«.» W«H (U« * Dealer! : Write Jar Quantity Prion. KNOCUD-OOWN VARIABLE CONDENSER MONEY -&A VINO MUCKS •iwaii m. j. Cartoon by L. B. Hinckley- Army Radio Nights )LLOWING the success of the first army night broadcasting entertainment n the big station of the Westinghouse ipany, at Newark, recently, all Army >s commanders have been instructed by vVar Department to cooperate with local dcasting stations in entertaining the fans rspecially in establishing regular month- rmy nights* ijor-General H. C Hale, of the Second s Area, New York, who out on the first radio entertainment which made such that local fans demanded more, has arrangements for a monthly program. : nine corps commanders who cannot their own show on army radio sta- tions, will cooperate with local stations, fur- nishing band and vocal music, speeches on military science and training, or other forms of entertaining or instructive programs. Very soon now, each of the corps areas throughout the country will have a new source of radio shows. CRYSTAL SET "THE LITTLE" WONDER" SUt UNMOUNTED $4 Wonder in name ud • wonder in per- formance. Cannot be equalled lor the price Catchca diatinctljr everrthms with. IB 25 miles. Scad (or FREE catalog, "Little Wonder" art and U •tins radio iap- All . HOLLOWAY ELECTRIC SUPPLY CO. m TUrd Arena* Now Yarfc Subscribe for Radio World, f6M a year, $3X10 six months, $1 JO three months. -j^w Hard Robber Composition D A NF1 ^ r any given adjustment of the button, different resistances are i at different times. In the resistance of Mr. Danielson's n. the contact between the vari- tistance and the contact arm is » metal, so that the contact resis- zi a ins constant. A His* Panel, Witkwat a Bear. I etaee. TaMaa/lS, Tzttal/M, TnMnS/M. M ana. day. Nndfef nanta, dtnle, and km VariaaBOtaWL VarHinajlan. Sachet* and el the of CnSa, Vnlnnnv V. Largest Discounts. ad Denlerat Write lar p ALLIED RADIO COMPANY. INC Dent. D. *• SEVENTH AVENUE, NEW YORK CITY, WANTED— A Ko.onle New En«*and Rananaentatlve. CAREFUL ATTENTION Cim TO ALL RADIO ENTHUSIASTS For CORRECT RADIO MAILING LISTS Use THE POCKET LIST at Bad* MaiMrfaetarart. Jabbara and Daataro la tha rmiad faiataa and Canada, faeeed Qaartarlr — Jan April. Julr ami Olotoar. Omhrr. 19JI. In» •Bmrttd ta Sn«»mlw» IStn. IMS. Cuanaae ■ ■hrw dlfTamt haa •« l*r» — trvl ■ lt*»ibrd«li, arrauad by Ma an, aad team* and mm at Snaa. Cantalidaa atvraclaalat; 15.000 namaa and addraaaaa. W, hata h*«i amrtiarMitr airafal to aat *• H tnat but Manofaatatw. Jabbar and Daab* ■ Matad and, andar tha PROITR (LASBinCATlON. Meal nailing n.i owv-rrn. eharcr nara <h»n 1100 fof a Uat af tWa kln.1 ami. u a nila. tbaaa auppllad ara far from hHnf rorran. Oxaoara tola Uat with aat ataar. aad jau will And 11 to ha tha aarr ban abtalnabla anrwbara al an? priaa. Ortabar laiua rrada far iSatrttxjtiaa Paw—baa tSth. Prlea IJ 00 par aapr. ar lit 00 pa* Jaar (foar la- aoaa. lurlihtlnf tnonihlr nipt I'manta ahlrh kara tha l'<t abanlulaH aamtt aad ap ta data at all Unaal. Oatabar adlllao limits! Band mr ardar antfe raHtUnca ladar. atUaa F. D. PICKENS, ten CARRINCTON STREET JANE5VILLE, WISCONSIN Digitized by Google

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Radio Goods that Stand the Test a (ample of yaw goods to war Technical on* Island, N. Y. It wtt be carefully RADIO WORLD'S endorse —sat will be eMIgatkm at any Mad oa your part. Talc U or bo own hi whatsoever oa the part of tho wttawat charge ar WORLD. calUac a l l' al Us Super-Sensitive Radiotelephone Head Set Manufactured by the Teleradio Engineer- ing Corp., 490 Broome Street, New York City. A RADIOTELEPHONE head »et worth toot- ing. It was tested out In various circuit! from 200 meten to 20.000 metera. When con- nected In on abort wnve-lengths, especially In copying- C-W itatlom and spark stations, in which very good rcaulla were obtained, eliminating the biasing uolae sometimes ex- perienced In other phones. In copying long- dlitance transoceanic meaaagei, thcae phonal responded very welL Tbe phones used were of the type C make. They are of aolid con- otructlon and neat appearance. made adjust- able to lit the head. The rcalotance of theae pbonea wai found to be 2,000 ohms. Na-Ald V-T Tube Socket Manufactured by Alden-Napier Co., 52 Wil- low Street, Springfield, Mass. A VACUUM-TUBE socket of genuine conden- alte. The best pnrt of this He Luxe soek- et, as It Is called, ii the patent clip. Thii clip makea a poiltlre connection to the prongs of the vacuum tube, under all condition!. There Is a wiping action acroai the bottom, and na the tube allps Into plnce this contact Is made nt tbe side. The operator using these sockets In his set may be sure that he Is free from the open-circuit trouble! In this part of his nppnrntns. As this contact Is slot less and made of genuine condenslte. It is practically unbreakable. It serves equally well for 5- wstt power tubei, ai there Is ample spacing between the contact strip and tbe bottom of • the base. » • o Na-Ald Small V-T Tube Socket Manufactured bv Alden-Napier Co., 52 Wit- low Street, Springfield, Mass. AVACUUM-TUBB socket which requires very little room on n panel when space Is limited for mounting sockets. This tube socket Is molded of genuine condenslte and holds the standnrd mnde tube. It Is neatly constructed. Spring contacts are provided to mnke quick connection with the different prongs of the tube. This tube socket Is uot affected hv the hent of the tubes or the heat of 'he soldering iron when soldering connec- Uont. . , . Na-Ald Condensite Dial Manufactured by Alden-Napier Co., 52 Wil- low Street. Springfield. Mass. A DIAL of genuine condenslte which will not warp. Tt n'lnwa the rtlnl to run true. It Is one of the S-lneh din's on which the lingers mny be placed on the knob without covering the numbers on the bevel edge. It Is nniqne In design. With Its elimination of excess material. It reduces the absorption losses considerably. ^ "P-T" Ultra-Sensitive Crystal Detector Contact Wire Manufactured bv "P-T" Crystal Contact Co.. Box 164, Boston, Mass. An n'l who hove wn«*»fl with eerstal de- tectors are aware, the great disadvantage a solid rectifier presents Is the difficulty of maintaining It In sensitive adjustment. A "P- T" Ultra-Sensitive Contact gave tine results, using a light-contact mineral. When used with an ordinary good specimen of crystal It waa extremely stable In operation. Be sure to keep the crystal free from dust or moisture. Never touch It with the bare fingers, aa the natural oil of the akin greatly reduces Ita aenaltlvlty. If necessary, clean the crystal with soap aud water or alcohol, using an old tooth brush. _ . To secure the best result! with the "P-T" contact, use a very short piece of this delicate wire, preferably leas than half an Inch. Do not coll It. but preaa firmly on the mineral at right angles, adjusting for best sensitivity and stability; a little practice will enable yon to secure both. Use tbe test bucser If avail- able aa It la of great value. The "P-T" Ultra- Senaltlve Contact Is Ideal for use In pocket, large portable seta, or In any type crystal-set manufactured. o • o Bakelite Socket for Vacuum Tubes Manufactured by I. R. Nelson Co., New- ark, N. J. AVACUl'M-tube socket made of genuine bnkellte. Of neat appearance and solid construction. It la made for the standard vacuum tube. It haa for Its contacts four metal springs, which mnke possible Instantan- eous connection when the four prongs of the vacuum tube are placed Into the locket for operation. o o o Crystal Receiving Set Manufactured by American Radio Co., Baltimore. A CRYSTAL receiver of neat design, made to operate over a wave bnnil from 200 to 800 meters. It bni for Its primary a coll, upon which Is a movable band employed to cut In or out the turns of wire needed. This Is con- trolled by a knob on front of panel. The tapped secondary, also. Is controlled by a knob and Is adjusted so that secondary mny be run In or out of primary for the amount of coupling needed. Tested. It was found to re- cord radiophone messages approximately twenty-five miles, using outside antennne. It has, also, two mounted crystals whereby tbe listener mny use either crystal he wishes In case one falls him. • • o Microstat Vernier Rheostat Manufactured by Microstat Company, WU- Itamsport, Pa. THE MICROSTAT la a vernier rheostat on an entirely new principle, of neat design and construction. Its purpose Is to allow the possibility of securing exact filament adjust- ment over the ordinary wire rheostat. Labor- atory tests show that It Is equal to ten times the possible calibration of a wire rheostat. Where the smallest amount of filament cur- rent Is needed, especially when working with a critical tube, this rheostat was found to mnke good Its name— "the rheostat with a thousand adjustments." One knob operates the control. No pinning or pulling of knobs. Jtifct turn. The exact calibration of the microstat Is due to the gradual entering of two points Into a resistance material: which gives tbe exact and most minute measurements of cur- rent to the filament as the operator brines the points together or separates them through the screw hand'e. The microstat takes up very little room on the nnnel. with each part care- fully and accurately machined. New Firms and Corpora- tions Huah-A-Pbone Sales Corp., Manhattan, chat- tels, $2.10.000; A. P. Wultsloger. W. 1. Cobb. A. II. Ualluin. (Attorney, G. Uoerner, 27 Ce- dar St., N. V.) New York Aerial Concert Corp. Manhattan, f20.iion : i. 3. Huley, J. A. and M. U. Nugent. (Attorneys, Nugent * Nugent, 280 Madison A v., N. V.) Itadlollve Corp., Brooklyn, bas Increased Its capU.il from 110,000 to flOO.OUU Radio Winding Corp., Manhattan, has In- creased Ita capital from $10,000 to $20,000, Southern California Radio Trade Associa- tion. President. Loo Taufenback, president Western Itadlo Electric Co.: vice-president, Al Meyers, manager L. J. Meyberg Co.: secretary. Dean Karrati, manager radio deportment C. K. Klerulff Co.: tresaurer, U. 8. Corpe, presi- dent Coast Radio Company of El Munte. Balentlne Radio Company, 808-300 Bcollaxd Bldg.. Dallas, Texas. Dallas Radio Supply Co., 1927 Main BL, Dallas. Texas. Surf Electric Shop, 102 Strong Ave., Apple- ton, Wisconsin. Psclflc Electric Company, 110 South Main St. Sheridan, Wyoming. A. Williams, prop. Chaudler Electric Service Cov 8L Marys, Ohio. Talt Knob and Dial Co., Manhattan, radio Instruments, $50,000; R. L. Talt. H. Rcutt, L B. Cuiiilcid. (Attorney, M. i. Spalekhamer. 118 Broadway, N. Y.>. . Radlaud Corp., Manhattan, radio. $20,000; J. Periuiulb, R. A. Zadlg, E. II. Bronui-r. (At- torney L. Bronner, 309 Broadway. N. Y.) Pruver Electric and Machlue Co., Manhat- tan $5.o«0: D. and A. Pruver. (Attoruey, A. Weiss, 154 Nassau St., N. Y.) Harlnett Electric. Hempstead, Nassau Co., $20,000; T. J. and R. J. and K. J. llartnett. (Attorney, T. 1. Cuff, Hempstead, N. Y.) Lyradlon Manufacturing Co.. $1,250,000; Harry U. Phillips. K. J. Conard, Charles On, Chicago. (Corporation Trust Co. of America.) Dealers Make Mistake by Rating Receiver Sensi- tivity in Ohms. M\rES, '■ * Ter7 g°°d receiver. It has a * resistance of four thousand ohms." This is the sort of sales talk that many radio clerks give to unwary purchasers of headsets. In talking so, they not only show ignorance con- cerning telephone construction and design, but help to create an impreesion that it entirely wrong. They are reaponaible for the belief that the sensitivity of a headset ia indicated by the resistance of the receivera. In commenting on this, Frederick Dietrich, president of C. Brandeo, Inc., recently said the policy of selling headsets on the strength of their resistance ia wrong and should be discouraged by dealcra. It not only hoodwinks a misinformed public but ia a gross injustice to manufacturers who, for sound technical reasons, do not wish to carry the direct-current resistance of their headsets to such a high value. One might aa well mraeure the horse power of an automobile by the siie of its carburetor. The average two- tnoitaand ohm headset is as sensitive and. in many cases, more ao than the receiver with a reais'ance of four thousand ohms. Radio re- ceivera should be rated by their impedance. The Brandes headset ia designed to have the same impedance as the average circuit in which they are used, since it has been found that this gives maximum efficiency. This impedance variee, of course, with tbe frequency of tbe current Tbe Brandea company haa taken, aa a atandard, one thousand cycles; and, at this frequency, their headsets have an impedance of twenty-tiro thousand ohms. It has been found that thla ia the resistance of the average crystal or tube circuit. Thla, however, does not guarantee the efficiency of a headset, since there are many other requirements and features that determine the operating efficiency and sensitivity of a radio headset. Digitized by Google

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RADIO WORLD 23 Mysterious Selenium Metal Discovered a Century Ago, Now Important to Radio, W 'ill Do Many Things By Maurtce Freidlander Live Wire Radio Co. SELENIUM is an unknown substance to the layman. Scientists admit that they have not mastered this mysterious, non- metallic, hexad element which occupies an intermediate place between sulphur and tellerium. It was discovered by Jona Jakob Rerzelius, the Swedish chemist, in 1817. It has taken 105 years to perfect selenium so that, in conjunction with radio, it now becomes a foremost substance for the scientist, in- ventor, and experimenter. F. V. Madaler, after fifteen years of research, has per- fected, at his Selenium Laboratories, the most sensitive cells on a large scale which are guaranteed more sensitive than any cell manufactured. Selenium is produced in two different forms: rods and powder. There are two different colors: reddish brown and black. When melted it has the consistency of ceil- ing wax and is shiny black color. In this condition, it is practically a nonconductor; but by passing it through a chemical process, it will change in color and become an elec- trical conductor very sensitive to the light That means it will alter its resistance to electricity if more or less light is reflected on it This very interesting action of selenium started scientific men throughout the world to discover more about this mysterious metal from a scientific and technical form of view. Selenium, it is claimed, will solve interesting radio problems: seeing by wire and produc- ing electricity from day or sunlight. Selenium cells are already in use for switching on and off electric lights on a life buoy and in outlying districts: starting and stopping machinery at a distant point, by wireless; measuring the light for exposure of camera films; transferring pictures by wire or wireless; measuring light of sun, moon and stars: registering railroad lights and electric-light meters; reproduction of sound waves as produced by music : avoiding friction in electric clocks, assorting cigars, coffee beans, and, in fact, any article where a difference in shade from white to black is to be distinguished; protection against burglary. The inventor will realize the big field for selenium. The scientist of the past was unable to make or buy the proper selenium cells and, therefore, could not complete his invention. Selenium cells are not easy to make, as the most important feature must be in permanency in sensitiveness and action. Selling Goods by Radio Department of Commerce's "Sell-it- by-Air" Service Hailed by Mer- cJtants TIPPING off American business men. by radio, in regard to foreign sales-open- ings in order to get the jump on America's competitors for the world's markets is the latest trade promoting stunt of the United States Department of Commerce. Inquiries for American goods coming in- to the Bureau of Foreign and Domestic Commerce from consuls, commercial at- taches, and other government representa- tives in foreign countries are now distrib- uted to New England manufacturers and merchants, through the air. by the bureau's Boston office in collaboration with the WGI broadcasting station at Medford. Mass. The service was tried out one night re- cently, as an experiment. By first mail the Parthenology The dictionary says it is pronounced like this: par-the-nol-o-je and means the scientific study of virginity. Think of the Seventy Thousand who read RADIO WORLD every week that have never seen your advertisement. Here is a study in virginity, for RADIO WORLD offers you a virgin field to mer- chandise your radio goods. Up-to-date radio "fans," dealers, jobbers read RADIO WORLD — because they get all the radio news — four to six weeks earlier in RADIO WORLD than they can get it in any of the old radio monthlies. Take this little lesson of parthenology to heart, make a scientific study of this new virgin field RADIO WORLD offers yon. Write Fred S. Clark, manager of RADIO WORLD, 1493 Broadway, New York for detailed circulation statement, and tested results on keyed advertisements. Better still, send us a four-time trial order at $450 per inch, right now, before we double our rates. RADIO WORLD is a marvelous, quick-action result-bringcr for classified ads; rate, five cents a word. next morning, several letters were received from nearby firms. One of the leading New England manufacturers of artificial leather, who happened to be "listening in" that night, learned of two possible openings for his goods — one in Mexico and the other in Colombia. He was much pleased, com- mending the Department of Commerce for taking advantage, of "this most valuable time saving device." In the opinion of an- other New England merchant, the new "sell- it-by-air" service should appeal particu- larly to the out-of-town manufacturers and merchants who are not in daily contact with the offices maintained by the Commerce Department in Boston, New York, San Francisco. Chicago, New Orleans and other leading cities. "For example," says this executive, "there are many manufacturers interested in radio who wish to sell abroad, but who are pre- vented from keeping in constant touch by frequent visits and telephone calls with the trade openings reported to' the government agents. As the radio stations reach _ many outlying cities, it would seem that this ser- vice should be of especial value to more dis- tantly situated business men within a wide radius." Selling American goods in foreign mar- kets, by radio can be extended readily to Coming Events The cditon of RADIO WORLD will »Udly publish news items of all contemplated radio •hows and expositions. Keep us posted by mailing- full information. ANNUAL SHOW OF THE ST. LOUIS RADIO ASSOCIATION, St. Louis, Mo., October 4 to 7, inclusive. CHICAGO RADIO SHOW, Coliseum, Chicago, III., October 4 to 22. U. J. Hermann, managing director, 549 McCormick Building. RADIO CLUB OF AMERICA. First autumn meeting will be held the last Friday in Septem- ber. Renville H. McCann, secretary, Columbia University, New York. CINCINNATI RADIO- ANDELECTRICAL EX- rsition. Music Hall, Cincinnsti, O., October to 7. inclusive. TRI-STATE TOBACCO GROWERS' RADIO SHOW, Covington, Ohio, October 21 to 28, in- clusive. NEW YORK ELECTRICAL AND INDUS- TRIAL EXPOSITION, Grand Central Palace, New York City, October 7 to 14, inclusive. NEWARK'S SFXOND ANNUAL RADIO SHOW, Robert Treat Hotel, Newark, N. I., October 4, 5, 6 and 7. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January U to 20. inclusive, 192], George A. King, director of publicity, 417 South Dearborn Street, Chicago. III. PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from Septemhrr. 1922. to May, 1923. AMERICAN RADIO EXPOSITION, Grand Cen- tral Palace, New York City. December 21 to U, inclusive. Direction American Radio Exposition Company. 120 Broadway. . BOSTON RADIO EXPOSITION, AND NEW ENGLAND AMATEI'R CONVENTION, Me- chanics Building, Boston, October 30 to Novem- ber 4. inclusive. SPRINGFIELD RADIO EXPOSITION, Spring- field Auditorium, Springfield, Mass., October 3 to 7. inclusive. SOUTH HUN CALIFORNIA RADIO SHOW. Comhlnprt exhibition of the Southern Cali- fornia Rrnnrimatlus; Association, the Bon t hern California Rndlo Association, and the South- ern California Ratlin Trade Association. Los Anr-pioa October 0 to It Inrlitslre. PHILADELPHIA RADIO SHOW, October i to 7, inclusive. other parts of the United States, is the opinion of Dr. Julius Klein, director of the Bureau of Foreign and Domestic Com- merce. Director Klein pointed out that his Bureau maintains thirty-four district and cooperative offices in this country in addi- tion to the Boston branch. The sending out of the information in each case is a problem for the local manager to arrange with some nearby broadcasting station as all of them have been authorized to under- take the work. NA-ALD SMALL SPACE V. T. SOCKET Sit sit. S tar II I*. Maeldsrt rmitsa rannaaatts. sit far amuitlnt. RmiSIi Sf wsalhte Miutlnf parts. Ke ewes swtal ts lataitsre irlth •friclfnry. UnaffWtao ay hast sf bulbs sr ssldrrlns Iran, araass esntane. Nlrksl pl»t«J " ssissa Wash eat slat. Prlaa sf lams prwhwlaa. Special proportion for deaths oiid fofcfcere. ALD EN-NAPIER CO. Deft, t. B Willow St. Springfield. Mass. Two important features for next issue of Radio World, Dated Oct. 7 Shall German Vacuum Tubes Be Admitted Free of Duty? The pro* and cons of this important question answered by technical and trade authorities. A Complete Up-to-Date List of Broadcasting Stations RADIO WORLD of Oct. 7 wfll contain also a complete list, alphabetically every broadcasting station in this country up to the day of going to press. Be sure of getting these two Important features, t newsdealer, or subscribe through your news agent at month*, or flM three months. RADIO WORLD, 1«J B Be sure of getting these two Important features. Place a standing order with it SS.M a jrear (SI issues), Broadway, New York. Digitized by Google

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24 RADIO WORLD LOWEST PRICES FORMICA RADIO PANBXS S/1S la. tblak. cut to sum. per M. la. So, MAGNET WIRE, par Vt la. Sasst B.M. •aan Bnam. D.CC. B.a.0. llTT 34.44 14.44 tl.M 14 4S 1.41 »« »4 .*« l.fl SS 5» 1.1* Ml HUGHES ENGINEERING CO. P. 0. Bat (7 Tarrsaa Park. Oak) AGENTS Wanted in every city and town to sell Radio sets direct to every home. Lsrge income and pleasant work assured. Wnte for agent's proposition— NOW. Perfection Radio Corp. of America 742 Broadway Now York MEYER TUBES AND CHOKE COILS Radio Accessory Products Dealer and afamt/aoritrer of Radio Apparatus Complete Radio Installations 219 Greenwich Street N. Y. C The FAMOUS GREWOL FIXED DETECTOR The GREWOL b a permanently set detector PRICE $2.00 In using the GREWOL you don't have to find the spot. Think what this means! THIS DETECTOR IS ALWAYS SET AND READY completely protected from dust. Ores the beet result*. If your dealer does not handle the Grewol send us $2.00 and we will mail one to you. WRITE FOR OUR TRADE PROPOSITION RANDEL WIRELESS CO. t Central Ave. Newark, N. J. RADIO SYMBOLS TINTS apsesrsd la Radls Wsrlj I Ns. it. i asst. 23. a ssaslsts tablt si ths radls syi ums la all slrtalu. II ysahavs ast sstursd ss«y ssad IB Mats. Or, bsttsr still, lubsciiba st $« a yssr: $3 fir S awftths. sr $1.50 fsr 3 ■•aths. sad luwa tubwrlptlan start vita that Itras. Rsdls World. 1413 Brsadvsy, Nsw Vara. RADIO WORLD TBLBPHONB. BBTAMT 4TS4 PUBLISH ED BVBBT WEUNBBDAT (Data* SATURDAY OP BUMS WKBK) FROM PUBLICATION OfTlCB. 1411 BROADWAY. NBW TOBK. N. T. BT HRMNB88T RADIO PUBJJCATIOHB CORPORATIOM ROLAND BCBKB HBNNBB8T. Bnttsr. 14aS Broadesj. Ns* Task, nuro a. CLABK. Maaacar. 1411 Breads**. Ns* Ten ASSOCIATE EOrrORSi Fred. Cane, I SUBSCRIPTION RATESi espy. S4.44 a paw. $3.44 I 11.44 Car tbr Add 11.44 a past ertm far _ _ ittsr. Mane SS, ISIS. at ths Pan OStos at Nee lam. Me* Tar*, eadar •as ast si Man* a. lift. IMPORTANT NOTICE t . ear aaaslats aars at tafcaa sonsellF ssattsrs a? fast and asaatsa la. SMUtr tax atal sf patents. Prtarlo sf stelae, ths . sat sf tsaaaual put lies, sr atkar ■ boss bs pttatsd la issd faltb aad aa ■ to bo t Has statsaMot Is sssds How Photographs Are Radioed Across the Atlantic Ocean IF you were to see some one operating what appears to be an ordinary type- writer, and were to observe that the machine was producing a picture instead of a letter, you would doubtless be astonished, says Henry Smith Williams in "The American," New York. Astonishment would not be lessened when you were assured that the picture thus transcribed by the machine reproduces a photograph that had been taken within the half hour over in Europe. The explanation that the picture had come across the ocean in the form of a radio code would not offer much enlightenment. Yet that phrase describes, after a fashion, the new method of sending pictures by radio that has been developed by Dr. Arthur Korn, of Berlin. The machine that inter- prets the code is an ordinary typewriter, merely modified so that it types dots of vari- ous sizes instead of letters. The operator who receives the code has nothing to do but strike in the sequence the keys repre- senting the groups of letters that have come by radio. The picture thus typed out is made up of dots of different sizes, much like the ordinary half-tone printed in a newspaper or magazine. The dark portions of the pic- ture are made up of larger dots; the light portions, of small dots; and the intermedi- ate shades of dots variously graded in size. When this is understood it is easy enough to see how the typewriter builds up the pic- ture, and we begin to get an inkling of what the code is like. The letter A, for example, of the keyboard may be repre- sented by a fine dot, letting white paper show to make a high light; and the letter P, toward the other end of the alphabet, by a coarse dot, building up a deep shadow. It remains, however, to explain how the (art par F * ■ REPRESENTATIVES WANTED! ' n wanta young hustling subscription representatives in every college, school, rss concern thruout the country. Send us your name and address for full A'ORLD, H83 Broadway, New York City. code of grouped letters was made at the transmitting end of the line. And this, it appears, was by far the most difficult part of Dr. Korn's problem. The method, briefly stated, is to roll a negative of the original picture about a glass cylinder upon which a beam of light plays intermittently as the cylinder revolves. Shadows of varying intensity are thus thrown on the surface of a cell made of the strange metal selenium, which has the curi- ous property of transmitting electricity more readily when illuminated. A highly ingeni- ous mechanism causes a telegraphic kev actuated by the current passing through the selenium to produce the dots and dashes of the Continental Morse code in such groups as to represent a different letter for each of seventeen graduations of light, so that the letters from A to P are represented. The message sent by radio consists only of these groups of letters, and, of course, the typewriter that is to reproduce the pic- ture is constructed with the same corres- pondence between letters and dots. The transmitting machine works auto- matically, sending its groups of letters in sequence determined by lights and shadows of the picture; and at the receiving end an automatic recorder may take the message, reproducing the groups of letters in the same sequence. Then a typist, who knows noth- ing whatever about radio, may reproduce the picture by merely striking the keys of the typewriter in the sequence called for by the copy. Thus the mystery of sending a photograph by radio across the ocean disappears — but not the wonder of it Even when we un- derstand how the thing is done, it still re- mains a scientific miracle. Amplifier Using Alter- nating-Current Supply THERE has been developed at the Bureau of Standards, Washington, D. C, an amplifier which uses 60-cycle alternating current to supply power for both the fila- ments and plates. The necessity for stor- age batteries and dry batteries is thus elimi- nated. The final form of amplifier uses five tubes and a crystal detector, there being three radio-frequency stages and two audio- frequency stages. A description of this amplifier is contained in a paper by P. D. Lowell, "Note on the development of an electron-tube amplifier which uses 60-cycle alternating current to supply power for the filaments and plates," which appeared in the July, 1922. issue of the Journal of the American Institute of Electrical Engineers, volume 41, pages 488-490. It is expected that this paper will also be available as a publication of the Bureau of Standards in a few months. BUY "RITE" Set of three rheostats, one Kloener Vernier, and two none vernier knobe to match Teagle Sockets — for base or panel mounting JR Switch Lever, 50c value J» Vernier Condenaer— 46 Plate MS Vernier Condenaer— 23 Plate 4Jt D. C. or S. C. Jacks M 75c Dubilier Condenser Jt 35c Dubilier Condenser JS 65c. Grid Leaks JS $4.00 Varicoupler ZJS All range coupler 7JS Crystal Set complete, with doable ear phones, antenna, etc., ready to install MM AD Armatrong Parts In Stock. Pontage Paid. Dealers write for catalogue. RITE RADIO SHOP Cer. 4th Ave. end Pacific St. BROOKLYN, N. Y. I Mask frsai L. I. R. R. Statiss Tsl. Stomas SSI 3 Subscribe for RADIO WORLD. SMO a year, $3.00 six months, $1.50 three iiionths Digitized by Google

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RADIO WORLD 25 COLE Variable Condensers 88 £. Kinney Street Newark, N. J. AMATEURS Buy row parts and Mb wlm the dMere buy. Ws ara manufacturers and will ssll you St wholaeast pricss. Federal Phonos TTSS Ohms. Tursr. Phooes-3a*» Ohms Kloener Vsraisr Rbsostat . Porcoloin RhsosUt Tn Oar Utt Prist us* IMS ts* AM IS* LIS JSS *J» 1JS Write for Free Catalogue No. 100, containing hundred* of bargain* PERFECTION RADIO CORP. OF AMERICA m BROADWAY NEW YORK Tha N attest Short Ware Ti Only $CM * PP on 1 lb. Sand far aaasphlet. Order through year L. W. GOODMAN DREXEL HILL. PA Dr. Mm*, at Ctdseae. writes: "Mi sefsstt, strtansasrs sad tans tsaplsr now re lata las Had Your "Ethercise?" Early Morning Physical Culture Now Comes by Radio Waves OETTING-UP exercises by radio, begin- O ning at 7 o'clock each morning, is the latest use to which the radio has been put On September 5, a series of weight-reduc- ing and weight-gaining exercises, designed for various members of the family, was in- augurated and broadcasted from Ararad Station WGI, Medford Hillside, Mass, as a regular feature of its program. The object of this course is to place at the disposal of all radio users the most ap- proved methods of physical efficiency. Three exercise-classes, lasting fifteen min- utes each, are held every morning. These personal efficiency courses are in charge of Arthur E. Baird, head of the Department of Physiotherapy, Caines College of Phys- ical Culture. While this use for radio is entirely an experiment, being the first time such a course has ever been attempted by radio — in fact, the first time a radio broadcast has been given at this hoar of the day — reports indicate that the exercises are being tried by people all over New England. One young woman wrote in that the little girl of the house, arising early one morning, saw her mother bending over and waving her arms with the telephone receiver on her head. The little girl was so frightened that she notified the neighbors. The three sets of exercises are graded as follows: the first for the normal business man or woman who wishes merely a set of toning-up exercises ; the second for those who are overweight and wish to reduce, and the third for those who are underweight and wish to build up. The exercises are accom- panied by talks on personal hygiene. An Epitaph BILL, the burglar, tried to crack A safe protected through the back; The let-loose voltage wasn't slow, And Bill's gone where the burglars go. — "Practical Electrons.'' The "COPPER GIANT" "B" Battery IS GUARANTEED FOR TWO YEARS la ANT reerlrins set. bassuts It dots DM deterio- rate iNli ■temsns Idle. TMa Is t rer, tars* Utter? dstUssU for itat loners tr setel-ponsbls InsUllsUsos where absolute rsllsHHtr seer s per- iod sf rears Is tbs first ooost deration. Stsadard Toltssss — It. SO and ISO. Asj ealUfs nadt to order. Write for lltuitrerjens J. A. RfTTER, I^nadoaras, Pa. Agents LAROB sIANUTACTUBRB SHIRTS wants Aetata ts eoaplete line of shins direst ts wearer. Kirluil'o ntuems. Els eslues. No capita! tr saportsnee required. Write for free samples. SUDIBON SHIRT KILLS 601 Brosdwsx Neat Tsrk. N. T. $4.00 CONDENSERS, $1.38 Vary njssst 43 or 23 plate $850 PHONES, $3.98 Ml Ohm Turners RADIO ENGINEERING COMPANY 2 W. JSth St, N. Y. C. Quality Radio Products . .... Hssassts sad Lsadtpssksn Osttlst 4 Wssslsttsa It esse Ron Usretrssl S Plats Vsraler, 21 sad 41 Plats ' store, Rsdls Stsraat Bsrtsrttt i sad Dee tare: Writ* tr Wire For tat Rltsset Preossttlss la Rsdls. Frederick H. sss Prodcn Incorporated lorsss QHy. n. J. Pictures and Facts About Armstrong Amplifier Radio World of pic tarts, d las rases and arttcloo rasardiaf tha Bow Sapcr-lrgemeratiTC AaaaMnar. The ben cootaiaina this ■aserial era tiT* ^ l»<y IS. eed Thcjr arm bo aaat postpaid cm IS ceats each, the foor ooaass • ceats. Or roa can ssU year; t&flO, ate atoathai and here ronr ssssecription surt with the aeasaer Mai Jena 34. RADIO WORLD CO., MM way. New York. CASTINGS BRASS, BRONZE, ALUMINUM Our Motto "SERVICE" THE ANCHOR BRASS & ALUMINUM CO. Ninth and Freeman Sts. CINCINNATI, OHIO

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26 RADIO WORLD Remington Terminal Indicators 5 CENTS EACH A REMINGTON rving imitation. Flu in japanned,' whit* enameled A perfect binding poet. ji^wum, wbiw letter*. Supplied in the following: Antenna, Ground, Phones, Grid, Inpnt, Output, A Bat +, A Bat — , B Bat +, B Bat — . Lettering in two position*. Order direct from ad. DraUril Writ* t* XNmmlif RADIO CORP, Type • FRANKLIN, MASS. DIRECT BY MAIL Tillman* Potentiometer Fast Seller One of the finest product* on U 1. MADE ENTIRELY OF BAKEUTE 2. FREE MOVING AND SILENT LEVER S. THREE UNIT BINDING POST Other high dase item* write for catalogue. Plica SMS Prepaid, cash with order or C O. D. Antenna Light Wire Plug $1.75 Radio Frequency Transformer. . . 2.00 MORE DEALERS WANTED GENERAL MERCHANDISE COMPANY NATIONAL DISTRIBUTORS 142 MARKET STREET NEWARK, N. J. "Spiral* Speaks" THE IDEAL LOUD SPEAKER Complete with Unit and Cord COMPACT — leea than Sxtttxt Inches yet the SPIRAL sound chamber is two feet long — aa long as the horna used In the very largest instrument*. POWERFUL— direct comparison with other speakers cost- ing up to 125 shows SP1HULA CONCERT to give greater volume. Uilng a small aerial and an ordinary net with two stages of amplification we receive Atlanta. Qa. ; Nashville, Tenn. ; Kansas City, Mo. ; and St. Louis. Mo. — stations from six to seven hundred miles away — so loud they can easily be enjoyed by a roomful of people. Nearer statlona come In as loud as the loudest phonograph music. BEAITLFIL — finely proportioned, with a fine hand rubbed natural wood finish and bronxed throat, we believe you will agree with us that SPIROLA CONCERT Is the most beautiful loud speaker on the market today. FLAWLESS REPRODUCTION OF SPEECH AND MUSIC — this Is what SPIROLA CONCERT was primarily designed for — to eliminate the distortion and metallic tone so com- monly beard — and we have succeeded completely. W* want you to actually hear SPIROLA CONCERT for youraelf. If you are a doubter due to previous experience so much the better. If you can not find it at your dealer aend us $12.60 and we will aend It to you prepaid. Try It out for ten days and then If you wish you can aend It back and your money will be Immediately refunded. We take the r!sk. L. H. DONNELL MANUFACTURING CO. Dept. B, Box 7t ANN ARBOR, MICH, SUBSCRIPTION BLANK RADIO WORLD COMPACT— POWERFUL, Beautiful in Appearance and a tone AS CLEAR AND NATURAL AS LIFE These things make RADIO WORLD Please send me RADIO WORLD for 1493 Broadway, New York City. months, for which please And enclosed $ SUBSCRIPTION RATES: tingle Copy t U Three Mont*. 1.50 But Month* 3.00 One Year (S3 Issues) 6.00 Add $1.00 * Year for Foreign and Canadian Postage. Radiofacts A VACUUM tube may be used as a rec- tifier, or detector, of high-frequency oscillations. When connected up to the proper circuit, it performs this function with as much efficiency as the crystal detector. * * * The chief problem connected with direct transmission by wire and radio, those of amplification with proper modulation, seem to have been solved, and the happy com- bination of wire phone and radiophone opens up new fields of usefulness to these twin wonders of modern science. * * * Practically every minute of the day and night the radio news of foreign countries comes over the radio waves. If you have a radio apparatus with vacuum tube* adapted for short-wave receiving, you might as well increase the inductance and capacity, or put up an extra long antenna and listen to the stations in almost any country on the globe. » * * Arlington broadcasts its time signals 11.55 a. m. to 12 noon, and from 9.55 p. m. to 10 p. m., Eastern Standard time. * » * Having your aerial higher at one end than the other will not be a disadvantage un- der the circumstances, but a complete ad- vantage, because it will place it diagonally in relationship to the aerial of your neigh- bor, rather than in parallel. * * * Why not a "radio-order house" to sup- plement the mail-order business during con- gested shopping periods, such as Christmas? * * * There is one material in the many places of radio apparatus that cannot be replaced by any substitute scientists have as yet dis- covered. This material is mica, a mineral substance having unique dielectric properties. It resists the passage of electricity even at remarkably high voltages. It is a material which forms an invaluable function in radio. * * * Learn the code if you want to get the full enjoyment to be found in radio as a hobby. * * * In stores where the radio department represents an investment of $1,000 or more, that department should be put in charge of, not necessarily, a radio expert but a man who is thoroughly familiar with radio parts, installations, and hook-up problems. * * » It is more than probable that within an- other year every town of any size in the United States and Canada will have a broad- casting station. * * * When one considers that a good talking machine costs at least $100 and a good radio-receiver from $15 to $20, it is ob- vious, as the technical details are perfected, to what extent radio will grip the public * * * American radio companies are developing systems of radio communication with Cen- tral America, with New Orleans as the main centre for American reception and transmission. * * * The principal reason why radio-telephony is very little known in Italy is because all the inventors find that if they wish to have a chance to sell their inventions they must go abroad. * * * The rheostat is necessary because it regenerates the brilliancy of the filament. If the rheostat is turned so as to increase the brilliancy, more electrons will flow in the tube. * * * Slate, electrically, is a very poor dielectric and nonconductor. It was used in past years as a panel for transmitters, but it has not been used for receivers. At present, noth- DigitUdbUyP@are,ite °f hard ^ ■

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RADIO WORLD 27 SPECIAL TO AMATEURS Varionnloro S2.M VarxKoupUra 2.M 2 Stalor I Rotor (Set) .7S Vasiamator Braaa Set M Poitpaid REISMAN < tor tl.M NA-ALD GENUINE CONDENSITC DIAL m dial that rum lru». | *f^Ly Kramk mrriTtd oa tore! tad knob oo ahapnl that Aram da nat M.la Un. Thin odio irlUi olomr raduatloo to aaka oecvroto raadln* eoaj. 1'ao- ■ M tat am In awtal ImiH. Will on onup r (Mp. Ptolih and onaoarl paroaanam. tm frtn wlili lata guoJltf paoalbl* oaty tnraaca aaatilf prajurtlaa. Special dealer and jobber proimtiHon. An opportunity. A LD EN-NAPIER CO. Willow SL D**L Spriacfteld. Mom. Trying to "Raise" Us UEHOW the song hits sent out by idio don't seem so charming without iccompaniment of dancing silk-clad says the pert paragrapher of "The ing Telegraph,"^ New York. st think! When old Doc Snodgrass examining my heart action with a tscope yesterday he all of a sudden out, 'Hello I Hello 1 Is this Cen- m • • • e radio thinks it says he that has o hear, let him hoist an aerial.*' was lit out by "The News," Dallas, » • • lite the hopes of inventors and ex- The Taleradio Tuba Socket Whoac hamlaome design i* adapted far tabic or panel mounting. Of sheM-drawn aluminum. All part* perfectly insulated— laga are not eurraat-carrytout. Terminal! plainly marked. 2,000 Ohms. $6.50 ZZ* Okma, ftSti S.0N Obms, t»M Each Teleradio Supersensitive Headsets equal the performance of phone* selling at $12.00 and $15.00. If your dealer kaa aa* etecked Telaraatta PraducU wrtta aw attract DEALERS and JOBBERS write for oar PROPOSITION OTHER TELERADIO PRODUCTS S. It. ZS and O Platea, Bat price ara flJ*. SXJS, SMS aad SMS, SSc rtaad Fhcae and Grid Cul Sac each. TELERADIO ENGINEERING CORPORATION BROOME STREET NEW YORK perimenters the radiophone will never replace the telephone. It's too easy to hand a person "a good talking to by telephone without giving the other fel- low a chance to "talk back." With the radio, one can swear a blue streak into the transmitter and unless the desired recipient is "in tune" he can't hear a word of it.— "The Mail." New York. • • • Radio has afforded the young thing (the modern flapper) an opportunity to give her all-too-celebrated "line" a fresh twist, we gather from "The Globe," New York. She adopts semi-technical r»dio terms under the delusion that it adds smartness to her characteristic lii.go. "Quit the static," she warns her "twtedie" when the latter shows signs of becoming boring. Or, not being a mental contor- tionist, sometimes he fails to follow the trend of her conversation. Then, Ton* in, old dear," she advises him, "there's been a change in the daily program I* JUST OFF THE PRESS The most up-to-date Treatise on Radio Textbook on Radio By JAMES R. CAMERON 350 Pages. Profusely Illustrated. Written so the amateur can understand it. At the same time — TEXTBOOK ON RADIO — is a standard textbook for the technical radio student Text»« ON RADIO Order NOW and Be Sara of Your Copy! Goth Bound, $230 Flexo-Leatho, $3Jt This new TEXTBOOK on RADIO it the new big brother to Radio's three best sellers "Radio's Three Best Sellers!" HOW TO BUILD YOUR OWN RADIO SET. 2Se RADIO DICTIONARY, SOc RADIO FOR BEGINNERS, $LM Bay Them From Yoar Dernier or Direct From ECHNICAL BOOK CO 130 West 42nd Street, Dept W, New York

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28 RADIO WORLD f— Rocky Mountain Crystals— . BETTER THAN OALENA Ik* meat etoeltite alMCil rectifier knaaa. alas be Bead with an at Basra mm at On ■Vawatett, JSc.l Met Postxaaad Utmufectmrtrt. Jobbers. Dealers. Clubs. Apply for Special Trade Pnces Rocky Mmtahi Radio Predicts, be . t OHURCH «T, NEW YORK. H. ¥ , RADIO INSULATION "SPAGHETTI"— VARNISHES— WAXES COMPOUNDS— PAPERS— ETC. ESTABLISHED 1US Write for Price Bulletin and Sample*. MITCH ELL- RAND UFA. CO.. 14 Vasty M., N.V. BUILD YOUR OWN MM r*r*pi ■ m iv mmmw neei U-i. 4513 Raveatwsed A... CMaaaa. III. GOING — and Going Fast Wa km eery a tea- left aad tsey are Betas hart, est while they last will liatlaaa la Mil them it the reduced pries. VT 1 Detector and AmpUflar pM VT 2 Detector and Amplifier $Mt The abate tubes an itaa ranulna in J'a and W%, respoclitsly. "RADIO BUILDER" PLANS FREE! By Hall. Sc. LIBERTY RADIO CO. IN Liberty Street New York Oty 8HELTONE LOUD SPEAKER No tubing or horn to distort delicate Swella every into full richneea I SHELTONE CO. 2t Clinton Street Newark, N. J. iOO AT ALL GOOD DEALERS OR DIRECT BY MAIL GITHENS TRUTONE RADIO HORN— LOUD SPEAKER First one to sell on ten day trial Money back G Retail Price $21.00 Includes Loud Speaker Trutoae has been pronounced the beat en the market by experts. It has a clear true tone. Every radio fan should try Trutone and oempare It with ethers. If TOII deo't find Trutene the best, your money will be refunded. It la said en a ten-day trial money-bees guarantee. If net carried by your dealer write us. Distributor! and Dtolert. ttr.it/ AUTO PART* CO. 181S Trombly A Broadcasting Corpora- tion to Stabilize Radio AN interesting 'plan for putting radio broadcasting on a permanent basis is now being discussed among the makers of radio apparatus, says "Electrical Merchan- dising." Tue plan proposed calls for a "public- service broadcasting corporation" organized not to earn money but to spend it, and to be operated under the direction of — not radio or electrical men — but experienced entertain- ment people who know the public's tastes in music, lectures, and amusement pro- grams. To the funds of this broadcasting corporation, the manufacturers would be asked to contribute two per cent of their gross sales of radio apparatus. Figuring $100,000,000 of radio sales this year, it will be seen that the new broadcasting corpora- tion would start operations with an annual budget of $2,000,000. Independent manu- facturers and jobbers and dealers would also be given an opportunity to contribute to the broadcasting pool, inasmuch as all would benefit from a plan which made radio increasingly popular with the public In this way, at least, one of the knottiest problems in the whole radio situation seems to be on the way to a solution. With a de- pendable broadcasting service in operation, the dealer can sell radio outfits with the fullest assurance of his customers' satisfac- faction. Navy Day in the Air RADIO broadcasting will be employed in connection with the celebration of Navy Day designated as Friday, October 27, by Theodore Roosevelt, Jr., assistant secretary of the United States Navy, at the instance of the Navy League. While repre- sentatives of the Navy League and other Naval organizations throughout the coun- try will undertake to promote general in- terest in the Navy and its gallant traditions through meetings, concerts, banquets, and with the aid of the moving-picture industry, a number of the larger and more powerful broadcasting stations have been requested to send out a radio program, in this con- nection, all Naval stations have been ordered to assist in making Navy Day a national celebration to be remembered by radio fans. Either the Navy or the League will fur- nish speakers, glee clubs, or other forms of entertainment to radio stations cooperating. A special program is being planned for the Naval Station, NOF, Anacostia, D. C. k is probable that either Secretary Denby or Assistant Secretary Roosevelt will de- liver a speech on the work of the Navy. The Marine Band is scheduled for a spe- cial concert which will probably be broad- cast from Anacostia. The gigantic scheme of entertainment for Navy Day will, by the aid of radio, be carried not only to municipalities, but into the very heart of the country in every State, and every fan who owns a radio set should watch for the schedules and prepare to listen in. WJZ, Newark, N. J., got one step ahead of the Navy League by offering its station one night each month for transmitting speeches and entertainment. Such nights will be known as Navy nights. Naval officials of New York have accepted the offer of WJZ and plan to use, as one at- traction, the Naval bands of such ships as may be in port on Navy Night. Letters from the Navy League to the Department of Commerce District Radio Inspectors have asked their cooperation in securing the aid of broadcasting stations. It is said that most of the large news- paper broadcasters from the Atlantic to the Pacific Coast will also assist in broadcasting Naval achievements. Fifty-two issues for $6.00. Sub. De- partment, Radio World, 1493 Broadway, N. Y. C Superior Radio Products AH Parts. Beeerrtas Oats OaatpMe and la Oaths, ■aad far r ~" Dealers Write for Proposition RADIO OUTFITTING CORP. 410 rLsusTl«an^t.0r** "^sw^EIX, N. Y. Recomaeamod my Dealer* for RellabiUtr ADIO STORES CORP. VARIABLE CONDENSERS- PLUGS— RESISTANCE UNITS. ETC. If year sealer Secee't carry. aseVess Oast. 0, XIX Watt 14th Street. Nee Vara RADIO MAILING LISTS •••• RETAIL RADIO DIALERS eateries ti " Stat St, ky states, arias P ......... tW^„...... ,*7M . IS.M .10.64) . 4.SS IIS Bsdto eteetilaeturoTs. llll Radio supply Jebbera, IS* Owners of Radle Stations, per list 14*** Bartfe Aaesteure sod Managers af Btatiooo. per hi 7.S0 Thin are neatly typewritten aad ready as steal aa receipt of reaslttanaa est arms the eassept Oearaa- TRADE CIRCULAR ADDRESSING CO. I»« W. ADAMS STRUT CHICAOO. ILL. DRIVE 100 TACKS AND SAVE $25*00 Ford Roadster Top Ha- rare rl rut $3.19. Touring IS.M. and »9.»5. Chee- < relet. Douse or Maxwell 113 »5. All ether S pes- aenger ears 116.51 with J lata class lights. RcKUlar Side Curtains , 5.US up. Special Winter Side Curtains that open with doors Sit. US up. ford Seat Covers 18.11 up Ford Cushions 13.73. All roods aaroe aa ear Bafts, use. Quality the best and guaranteed to fit. Printed In- structions titan how to apply. Bend for samples Priest above Include delivery at your door. AUTO EQUIPMENT CO., 17 Cecal •treat ClsarsastJ. •. Welcome! Come in and hear the Coraco Radio Concert Dairy, • A. M. to f P. M. Iltk Freer. Stl W. 41ad at,, seat to ASMIarsaua Theatre Is the latest Ilea lest Improvement in radio. It connect] ana no tnatalladone expel to operate as s phonograph. If write for fall trrformation. The Coraco Company, Inc. 2X0 Wast 42nd Street Nsw York IMPORTED DETECTOR TUBE, $2.75 Haaufscturara' Susrsstsa 1000 Bnralst Hears This is a real $5.00 value 43 Plata Condensers 401 Mfd fljt ZS Plate Condensers M05 Mfd. SUE Jefferson Transformers $2JS *jm Ohms Frsnch Phones SSJt S3 at Vario- Coupler I2.7S Two-Slide Tuning Coils ».TS Msll Orders Filled Promptly Sesd for Complete List of Spatial, J. J. KELLEHER 14 UNION SQ. EAST Phase Stuy. 1636 "MIRAD" "Quality Radio Priced Right" 3 Plata Variable Condensers %\S» Mlrsd Varicouplsrs S.7S MM Ohm Double Hesd Phones 6M UM Ohm Single Head Phone IM (Money back (usrsntse.) Mlrsd S Plate Condenser Sjf Mlrsd 43 Piste Variable < Mlrsd Detector Unit Mlrsd Two-Step Amplifier... Postage Paid Dealers' Sample of Above 25% Off Miracle Radio Mfg. Co. INTERURBAN BLDC, DALLAS, TEXAS DigitizBCfby Google -

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RADIO WORLD 29 PATENT Yaw Radio Um. Oaf tr Write f II E ADVICE ALADDIN ELECTRIC COMPANY, INC COMPLETE RADIO SETS WRITE FOR PRICES. 71 Wart Broadway N«w York CJty The Nelson Radio Parts Co. Manufacturers and DUtri baton of RADIO APPARATUS Write for Catalog. ACADEMY STREET, NEWARK, N. 1. Tel. Market 4066 AGENTS Wanted in every city and tows to eeU radio apparatus. Good commissions. A few nocking agencies open to reliable parties. DELANCEY, FELCH ft COMPANY U Mwtiaf St. Pawtucket, Rhode " Law Storage Battery Constant voltaax. Urge/ amperage. Will ma two nenthe without recharging. Attract™ Dnltrl' Dutonnts Writ* for Drtoilt WILLIAM LAW COMPANY Afeorn and Ssbla Streets. Providence, R. L RADIO BOXES All raws sastsiu *srk ear ■etiltltv. Writs Isr SPECIAL PRICES JOE MIFSUD & CO. 171 Canal Street New York CJty TiIiisisi Osesl *47i Boy Your Radio Receiving Set at Mannfactorers Cost Buy year Radio SuppUea at a largo dis- count below the list or retail price. U a saving el fUJs to tMMt oa a Radio Re- carvtag Set or If a saving of 2S% to «•% ea Rasas SuaaUes ketereoU you, write or KING RADIO MFG. COMPANY S21 Pean Ave. Wllklnebnrg, Pa. Improve Your Crystal Set Solid Gold Coatact Cat Whiskers. Win Not Corrode, Rust or Oxidise. Will last a lifetime. Try one and see how the Qual- ity of your reception is improved. Prie* each Special "ED MAR" Mounted Crystals. If it isn't the best you ever used, return it and we will refund the money. Price ISa Spider-Web Disks. Set of three *•» AJenaaaana Plate Variable Ah- Condensers. Sold Knock Down Only (Without Knob or Dial): 43-Plate *U* ZJ-Plate tl-» U- Plate SIM J-Plate CVernier) Me Oreer Olrett Frea Us. Seat PtetssM Is Yea. The Eddy-Marsh Company M Wsetaanetor St. Providence. R. I. Turning Print Into Sound by Radio THE Lee de Forest talking film (or "phonofilm"), can be hitched, after the film is developed, on to broadcasting in- struments, it is claimed, so that the voice pictures can be wirelessed great distances and then turned back again into sound waves, says "The Times," New York. So far, the problems of running a typewriter or a linotype by sound waves has not been mastered, but close approaches to it have been made. By the use of light similar to the pho- tography of sound waves by Mr. de Forest, the printed word has been turned into sound, so that the blind can read by ear. The arrangement of black and white in the ordi- nary letter causes such varying effects when the letters are intensely lighted and passed over selenium photoelectric cells that the electric current can be controlled by them so as to produce sounds which the blind can interpret into letters. In both the de Forest invention and the machine which renders the printed word into sound for the blind, the key is the peculiar property of selenium. In darkness this substance is resistant to electricity. In light it conducts electricity. In varying light it modifies the current of electricity pass- ing through it. In the de Forest invention the aperture for the admission of light for the sound-wave photography is said to be in some way controlled by the vibration of the sound. This produces the variations in the sound pictures on the film. When repro- duced these variations modify the light which passes through. The modifications of light keep the electrical resistance of the selenium cells in constant variation. The electrical current, is thus controlled by the pictures of the sound waves. The current is magnified by the audion tubes and in turn it controls a diaphragm or microphone, like that of the ordinary telephone receiver, fin- ishing up the process of reconstructing the sound. When There's An "R" There's Radio OYSTERS are in season and so is radio. Curiously, the two seasons coincide; if there is an "R" in the month, radio trans- mission is good. The radio season opened officially on September 1. and is now in full blast. In anticipation of the unprecedented interest in radio during the fall and winter, the Bureau of Navigation, Department of Commerce, is taking steps to minimize in- terference and insure, so far as possible, strict compliance with the law. The radio inspectors in each of the nine districts have been instructed to cover the principal radio centers and points where serious interfer- ence may be expected. On these trips they will inspect stations for license, examine applicants for radio-operators' licenses and determine whether the transmitting stations are adjusted to meet the requirements of the law. Claims Spirits Talk by Radio MRS. M. E. CADWALLADER of Chi- cago, vice-president of the National Spiritualists' Organization, says that she has made plans for the broadcasting of messages from the dead that may be received throughout the length and breadth of the land by all who care to hear. John Slader, a Chicago medium, it is reported, is working with Mrs. Cadwallader. There is no hc>i- tancy in Mrs. Cadwallader*s assertion that the dead actually converse with certain members of the living human race and her announcement that these messages can be broadcast, as if they came from the livine throat, has been greeted by the true l>c- licvers with acclaii.i. V-A-C-U-U-M-T-U-B-E-R-E-P-A-I-R-I-N-G g Stow- i JO I s™*?.00£ u Detectors 1 Amplifiers^ u Bepslrlae m il an sad • Mae* teaestea eimm mm as mm '£Z^r^, madtatten UV-Ms. UT-tel. Ceaaaasaea C-tee. c-sel. Peittttrs eatf sal* tilers 11.51. realties' far Tat reaalretf teste. «a eai rem. will arte tetlea thai fee res BM eiae ebartets stoat weld etpsel te tmrnm tr ■a eee takes We are see la s eeatlet seitt fer praapt dsgterlei tery reaths. A rvateaaMe am ear rentUUo>. lenfm-K trial will tea- George H. Porwll Co, law. WUT SOMtRVILLK. MAM. V-A.C-U-U-M-T-U-B-lvR-E.P-A-1-R-I.It-C U M T U B E R E- P A I R I N AdiUiUbH Rtdlt Ml,. Pr.du.t. Ce, ISt t. «»a II.. Wee Vert Radio Supplies' Vguriocoaplers, VariogagtaTg, Headsets, Trmatiormtn, Sockets, Rheostats, Etc. °^StT* Crystal Set Or Meaty Refunded PRICE, •lb $4 Send fifty crate for 20 tfieirml Urns trim) kmoh-*H. Aay RacSo Sat Mack to OreVar or Rep sir eel Sunbeam Electric Co. n THIRD AVE. NEW YORK MILLBRO RADIO SUPPLY 1S7 Seventh Avenue New York City NOVO B BATTERIES Medlaaa Variable, $1.00: Large Variable, gl.M. KiMe H'srage Batteries, M Ban- ners boors, f 19.7ft. Fall List mi Raaw Paris at Utroao*/ law Pratt NOVQ BATTERIEJ FOR rad: 5 VOLTS 22>S-45 & 105 N O I S EL,] DEPENDAffi GUARANTE' m ASK YOUR DEAL! NOVO MAM' FACTll RING NEK \ ( l l( K 531 SO DEARBORN ST..CHICAG01 Subscribe for Radio World, $600 » vear, $J.O0 six months, $1.50 three month' riifljtbpH !

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? DEPARTMENT AT k A WORD TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This area Is MaM for svsrybody who wsnrs quick action on ihart radio Sold. Readers a PATENTS Protect your Invsntion today. Write for 1923 Illustrated Book Free. Radio, Electrical, Chemi- cal and Mechanical eaperts. Over 30 years' eg- perience. A. M. Wilson. Inc. (Radio 3 AKI1). 310- 18 Victor Building. Washington, D. C. (Successors to business established 1891 by A. M. Wilson.) Dealers and Salaamen wanted to handle Sham- rock Crystals. See other ad. Good proposition to dealera. Send SO cents (or sample. Bathgate, 120 Autumn St., Passaic, N. J. FOR SALE. Grebe CR-8 and 2 step amplifiers. Irvin Maurer, Minersville, Pa. EDISON "B" Battery Els 181 Pleasant St., Maiden, Mass. BOYS! MYERS' HICH-MU AUDION. A tube which brings in the stations five times louder than other tubes. May be used as audio or radio frequency amplifier. Try one ol these excellent vacuum tubes. 85. Receptacle, $1. Postage and Insurance free. If unsatisfactory, return within five days sfter receipt. The Kehler Radio Lab- oratories, Abilene, 50, Kansas. WANT ED i COPIES of RADIO WORLD. April 22 and May It. 1*22. Mail us copies of these issues, or either one, with an accompany postal and we will send you a copy of the latest issue for each copy so mailed. RADIO WORLD, 1493 Broadway, New York. 28 WATT C W. and phone set including motor generator, 5 tubes, new, used less than 20 hours. Cost over 8250; sell 8175.000 cash. Box 152, Mshwah. N. J. WESTINCHOUSE RC Regenerative Recetoor and 2 stage amplifier in cabinet, 875; 1-6 HP. 10 Volt DC Motor-generator, SIS; 5 Ampere Battery Charger, 88. Further details on request. A. R. Leinbach, 137 Walnut St. Reading, Pa. CASH FOR OLD COLD. Platinum, Silver, Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash •»««, return msiL Goods returned in ten day* if you're not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. TUNING COILS, single slide, 81.00; double slide, $1.25. Bssrs finished in Blackrite. 6x6, 25c.; 6x14. 45c Include postsge. J. Zied, 530 Callow- hill St.. Philadelphia, Pa. HELP WANTED — MALE EARN fill ta 828* Monthly, expenses paid, aa Railway Traffic Inspector. Position guaranteed after 3 months' spare time study or money re- funded. Excellent opportunities. Write for Free Booklet G-151. Stand. Business Training Inst.. Buffalo. N. Y. THE LOOP'S THE THING. The coming aerial, moat simple and inexpensive of all when our blue prints and specifications of the two better types are followed. Sent postpaid for 81.00. No stamps. McGehee Development Co., Box 1337. El Paso Texas. "CLORADCO" RECEIVING SETS. Tuner, detector and two step amplifier, made of stand- ard parts in mahogany cabinets, 855.00. Made to sell for $85.00. Globe Radio 402 East 148th St.. New York. WISCONSIN Calena Crystals, 2 em. 88c, Ready now. Sent postpaid, A. £■ Beers, Bcctuwn. Wis. RADIO FANS! Send for our catalogue of Electrical, Radio and Mechanical books. Include* radio outfits and amplifying transformers. Price* reasonable. A. C. URl£ 4? CO., 333 W. Manhat- tan Boulevard, Toledo, Ohio. DO YOU USE A CRYSTAL DETECTOR T ARE YOU MAKING A CRYSTAL RECEIVER? Increase the efficiency of your crystal detector 1,000 per cent by using a "FT" Ultra-Sensitive Contact. Of special gauge and, alloy. Makes and holds a quick, ultra- sensitive, stable ad- justment. Using galena, you may pound panel or table without diaturbiog sensitivity in slight- est. Proved practical on shipboard by an old- time Marconi operator. Using a "PT* Contact on galena, Arlington (NAA) was brought in clesr st J .300 miles (below the Equator): and Arlington came in loud at 2.200 miles (off Dutch Guisns). In both instances, nearby shine as lag vacuum tubas were unable even to hear NAA. Aa to stability. Cape May (WCY) was worked over 1.0U0 miles, sending right through crystal with 2 KW spark, without effecting detector** sdjustment. Replace your old inseositlvo un- stable contact with one which will hold its ad- justment in sddition to giving louder signal* and music Indispensable for pocket acta and crystal detector-bulb amplifier outfits. A novice csn install. "PT" Ultra-Senaitive De- tector Contact, with instructions, t«nty-fiye cents coin or M. O. "PT" CRYSTAL CONTACT CO., Box 1641. Boston 8, Massachusetts. The man worth while is the man who can smile when his set has blown a tube. In the bright lexicon of youth there is but one word — Radio. Amateurs rush in where old-timers know better than to tread. Continual dropping wears out the phones. A radio set doeth good like medicine. Some amateurs know no law. What's in a name ? — radio by any other name would win the world. Code speaks louder than words. If the pen be mightier than the sword, then radio is mightier than the pen. — Florence G. Rogers in "Radio Journal." STANDARD HEADSET 2,500 OHM ausrsstasd ta be eseal af say phase (C HK sa tks sssrkst listing at tl.Ou «p9. I O Dealert and jobber* write. Standard Electric Sales Co. 848 Broad Street Newark, N. J. NA-ALD DE LUXE V. T. SOCKET Contact strips of laminated phosphor brants press flrssry ajralnst contact pins, re- gardless of rarlatlon la length. No open current trouble possible. Socket moulded tram senwlns Condenalte. I*rsetjeslly unbreakable. Blvrlal pro- tectee! slot, with eitertor reinforcement, t'nalfsrtsd by hast of bulbs ar soldering Iron. Alt stesss metal eliminated, abllng reception. Mar be ssad for 5 Walt IKMter tube. Highest Quality throughout Pries. TSa. Special proposition for itrnltri and robber*. ALDEN-NAPIER CO. Dsst, L 82 Willow St. Springfield, Mass. Finn Work Close Tuned Patent Pending VARIOMETERS Special Winding that will tche jruu Pittsbumh, SrhttitfiRily. Kansaa City and other stations, when BarupDitilrtl wl i h our V ar loemi pit* f. GUARANTEED TO DO THE WORK OR MONEY BACK We furnish Frss. Wiring Sketch Trlcle Call Mount with Special Lack Kaeb And You Can Buy Direct 1?2 Fifth A Ten us New York Gty Osland, Inc. "Digitized b" google

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RADIO WORLD Radio -Frequency Amplification Explained Interview with Charles Kilgour, Radio Engineer, Brings Out Interesting Information in. Regard to Phenomenon of Radiotelephony ALTHOUGH radio frequency amplifica- tion is no mystery to the average ama- teur, there are many, especially those who have but recently become radio fans, who will be interested in a brief explanation of this phenomenon. Mr. Charles Kilgour, radio engineer, in charge of the corps of engineers employed by the Crosley Manu- facturing Company, operators of the radio station WLW, in Cincinnati, Ohio, has made a close study of radio frequency amplifi- cation. "Everyone knows the purpose of the ordi- nary two-stage amplifier is to make louder the sound as originally received through the detector tube 'or crystal." says Mr. Kil- gour. "This amplifier makes any audible signal louder; therefore, it is called an audio-frequency amplifier. "The extremely weak electrical alternat- ing currents induced in the antenna circuit of the receiving set have a frequency far too high to produce an audible effect on the bead phones. Broadcasting stations usually use the 360-meter wave-length, which means that the current picked up has a frequency of more than 800.000 cycles per second. The lowest note of the piano or orpan has about 16 beats, or cycles, per second, while the highest beats approximately 8,000 times per second. "The high-frequency current pitked up from the broadcasting station is called a radio-frequency current, because it is at this high frequency that the message is radi- ated through space. Combined with the radio-frequency pulsation there is a low frequency variation which is the part we wish to hear. The detector so alters the current that the high-frequency part has no effect on the head phones, while the low- frequency part acts upon them, causing them to give out an audible note. This is called rectification. "Understanding this, it is apparent that a radio- frequency amplifier does its work before the detector has acted. It is inserted in the set between the tuner and detector. As in the case of the audio- frequency amplifier, a vacuum tube with its proper circuits is used to strengthen the electrical current. In this case, however, this is accomplished before the current has been rectified by the detector. One stage of radio-frequency amplification will not have as great an effect on the output as a single- stage audio-frequency amplifier of proper design, but it has several important ad- vantages. "If a great volume of output is desired, why do we not use more stages of audio- frequency amplification? We cannot ordi- narily use four or six stages because audion amplification becomes very noisy when cas- caded in this manner and sounds generated in the tubes themselves have a tendency to drown out the signal. On the other hand, a radio-frequencjr amplifier does not have this bad quality in anything like the same degree." VARIOMETERS AND VARIOCOUPLERS UNW1REO, PER SET tl-Sa Varieneter S auhocanj Mm, lit" I «»' toy rotor. wloOLoi torn and brut hardware, 91.1 POT eft. Varieeeepler— BUillta tub* a" I S" rotor ball aaa all bran hardware, ll.it per eat. Pleaaa Include II eentt per aet for poetafe. ARROW WIRE * RADIO COMPANY ISS ewreata Anew* Nee York CMr 5 FEDERAL $ 53- W. 2200 OHM PHONES We an Mattes oat ear etaek tad erfllseeal aaa aayebero Met tela earn reeelat of frae Mara, la leu et tee or ewe M M eeee. F. O. •. *•» York City. Bead reealttaaee vita order, leweedl- ata iklparaat J. H. * C. S. ODELL COMPANY fetaklleaed ISSt «e7-aaa WEST 42ND STREET NEW YORK CITY LOOK! Complete Unassembled Cabinet Two-Stage Regenerative Receiver Ail High CUaa Mould**! Parts $40.00 W. A. DICKSON DISCOUNTS IN QUANTITIES eat Eaat Fort St. Detroit, Mich. Latest Foreign Radio News THE first radiotelephone system to be established in Japan, will communicate between Fukuoka in Kyushu and Fusan, Morea. It is planned to connect this line with land lines. Considerable delay has been experienced in its installation, but the sta- tion, from latest reports, should be in oper- ation. The next installations planned by the Department of Communications of Japan are from Kyushu to Formosa and from Kyushu to Tsushima in the south and from Hokkaide to Saghalien in the north. A company is now being formed to establish a radiotelephone system between Kagoya and Osaka, a distance of about 120 miles. Effective June 1 last, the legal time in Poland will be the same as that of Central Europe. French radio-compass stations in Algeria, France, and Morocco give bearings on 450, 600, or 800 meters, as the ship station may desire. For each bearing a charge of 6 francs is made. American ship stations should obtain these bearings on the 800- meter wave. The new wireless station at Shabolevka, in Moscow, was able to receive messages from the recent Conference at Genoa. Mes- sages are sent by the commissariat for for- eign affairs through this station. The re- ceiving department is equipped with three apparatus, all of Russian construction. The station has two masts each 560 feet high. The wireless coast station at Bonifacio, Corsica, will communicate with any ship desiring information of meteorological order relative to barometrical pressure, wind (di- rection and velocity), condition of the sky, barometrical tendency, and the visibility and condition of the sea. The land line tele- graph rate is 3 cents per word and the coast station rate is 8 cents per word. The same information (given by Bonifacio) is obtainable from the station at Marseilles. The rate is the same. A Radio Necessity! Latest broadcasting map 15c That is, a complete broadcasting map appeared in Radio World, No. 8, dated May 20. Mailed on receipt of 15c. Radio World Company. 1493 Broadway, N. Y. C. "TUNING IN" TO THE RIGHT TUNE IS VERY SIMPLE WHEN YOUR CONNECTIONS ARB SOLDERED WITH THE NEW "POST SOLDERING IRON" (The Iran wHh the PlatJeum Heating Unit). Removable Soldering Tip H Actual Slav LIST 16.00 Deal (nod oopecloJry to cerrer every requirement for delicate efficient Inetmmcnt aa the anarkct. Attache* to an guaranteed. From your dealer , Jobber or write The Universal POST ELECTRIC COMPANY 3t EAST 42ND STREET, D)v. MS NEW YORK A Fitting Birthday Present for Those Interested in Radio Are you cudeellag your brain In an effort to think of an appropriate present far a rolotlvo or Wend? If that relative or friend la interested In radio, WHY NOT SEND HIM OR HER RADIO WORLD FOR THE COMINC twelve montbeT Sand us SS.N for each oubocrrption you want, and wa will place the names on our subscrtpttou Hat for on* year, postpaid, and we will also send epecia. Is the addraaaaa you sand us announcing that the subecrlptiono were sent with your comphmen Address Subscription Department. Radio World, lets Broadway. New York City. N. Y. Y0TJR NEWSDEALER will deliver RADIO WORLD to your home. In order to be aura of retting- RADIO WORLD regularly, and of not missing a single issue, we auggaat that you either aubecribe direct or through your news- dealer at MM a year (52 issues) SSett aix moo the, and tiM three m on the. Or instruct your newsdealer to deliver RADIO WORLD regularly to your home *■ ' make deliveries of paper whenever requested. Radio ■u ibim iwnuM. wr mnai your arnoaaer io^TlaW^dw^! Ntrw Vorf ^

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RADIO WORLD «• HAWK JUNIOR All mail orders given prompt attention. Shipped C. 0. D tlDi 1. Hawk, Jr., Detector Tube Set One of the molt remarkable and thoroughly efficient radio receiving sets of ita kind evar produced. It is a non-regenerative vacuum tub* set of small compact size equal to many outfits selling at ISO Ml, yet ^ _ _ „ ~ retailing at the amazingly low ^ J[ O.UU If you are a dealer you are certain to create a furore in your territory with this set aa a business getter. 2. Hawk Gyroscopic Variocoupler Genuine bakeiite ant hard rubber. Fahnestock connectors throughout used as standard equipment by the Gov- \\ (III ernment. List price ▼** e WW 3. Hawk Midget Most complete efficient detector A_ Sfflrts^St^: $5.00 4. Hawk, JuiHor A wonderfully selective crystal M , _ receiving outfit receiving up to $1(1 (If) 40 miles. List price sBlVsUV 5. Hawk, Senior Ideal vacuum tube receiver. Tuner, rotary plate, variable condenser, socket, rheostat, etc., in mahogany finish cab- Mt%r\ f\ c\ inet, wired and mounted. List |^^(J iiw 6. Hawk Amplifier Unit Two-step audi on frequency amplifier, elim- inates tube noises, and distor- AA tion is practically nil. Last $30.00 — 3«v I V • < 5. HAWK SENIOR t. HAWK AMPLIFIER UNIT HAWK RADIO MANUFACTURING COMPANY 150th Street and Melrose Avenue New York City Digitized by Gpogle

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ik-Ups for You to Test Uctober 7 15c. a Copy. wjMeu Running Lead-in Correctly from Antenna to House THE problem of bringing the lead-in wire into the home without interfering with the windows or defacing the house, is a problem. Where an aerial is used in connection with a receiving set, a small porcelain insulator tube, such as is commonly used in electric house-wiring, may be used satisfactorily. A number of special insulators are manufactured for tail purpose. Where the lead-in is to enter the building it is essential to bore a hole through the wall, if the building is a frame one, or through the window casing in other buildings. This hole should be just large enough to make the tubing fit snugly. The photograph to the right shows the method of bringing in the lead-in wire through the porcelain tubing. The lead-in wire is often passed through the tube from the outside and a small loop should be left outside the building to permit the rain and water to drop off both the lead-in and the insulating bushing. Where it Is not considered advisable to drill a hole la the window frame, a small board may be placed underneath or above the window, and a hole drilled through this board. Either of these methods will Permit opening the window without interfering with the wire. Both meet the requirements of the Fire Underwriters. Where a window is permanently closed, s small hole may be drilled in the glass and the wire brought through the glass. The proper grounding of the ground wire sometimes Purilea an amateur. The ground clamp is a strip of ■Mai made to fasten around the pipe. It is held in place by a clamping device. It is important that Hie pipe be scraped very clean. After being sure 7?' ill? pip" '* clMned the ground clamp may be attached. The small photograph above shows how to connect the ground to the ground clamp (Both photos C. Ksdol & Herbert News Senl COMPLETE LIST OF BROADCASTING IN THR I INIiTRH STATFK Al\in TANA HA ee

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RADIO WORLD TESTED AND APPROVED BY THE RADIO WORLD METEOR ANTENNA PLUG Eliminates ■use of outside aerial, install- inc Lightning arrester, static and interfer- ENCE. Used on Either D. C. or A. C. CONSUMES NO CURRENT CANNOT SHORT Has proved successful even in steel buildings on direct cur- rent under conditions thought impossible. $1.25 List JOBBERS AND DEALERS WRITE FOR DISCOUNTS G. M. JOST 1 Union Square New York Guaranteed 2500 Ohm Head Set $4.75 Complete Attractive ufacturers, SCOTT NOVELTY CO. 33 SPRINGFIELD AVENUE NEWARK, N. J. UNIT RADIO SETS Our sets approved and installed in Borough President's Offices of Queans, New York City. PRICE and QUALITY our premier consideration DMMtn- Ualtt $8.00 to tis.ee Anpllftsr delta Ta.00 to St.00 Tuner Ualtt Il.ee Detootw ud I step 2e.ee DlMv ass 2 Stop St.00 Detootor >nd 3 Stop 52.ee Tunlse Unit Detsetor ud 2 Stop 62.00 Dealers writs for proposition Immediate Deliver]/ American Ratio A Electric Co. 1U3 Broadway, New York City PATE Any single copy of Radio World, be- ginning with No. 1, mailed on receipt of 15 cents postpaid. Any seven issues for $1.00. Or send $3.00 for 6 months (26 num- bers) or $6.00 for 1 year (52 numbers) and have your subscription start from No. 1. Radio World, 1493 Broadway, New York. To the Man with an Idea I offer a comprehensive, experi- enced, efficient service for his prompt, legal protection, and the development of his proposition. Send sketch or model and descrip- tion, for advice as to cost, search through prior United States patents, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable me to accurately advise clients as to probable patentability before they go to any expense. Booklet of valuable information, and form for properly il 1 ueet. Writ. YOUR NEWSDEALER 11 deliver RADIO WORLD to your home. In order to be sure of getting RADIO WORLD regularly, id of not missing a single issue, we suggest that you either subscribe direct or through your news- eJer at SCjte a year (52 issues) $1*0 six months, and SI M three months. Or instruct your newsdealer deliver RADIO WORLD regularly to your home each week. Dealers will take standing orders and nice deliveries of paper whenever requested. Radio World, 14*3 Broadway, New York. RICHARD B.OWEN, Patent Lawyer 732 Own Building, Washington. D. C. 2276-S Woolworth Bids.. New York Cltv JUST OFF THE PRESS The most up'to'date Treatise on Radio Textbook on Radio By JAMES R. CAMERON Whose textbooks are used and indorsed by the U. S. Army, Navy, and Deportment of Public Instruct! oa 350 Pages. Profusely Illustrated. Written so the amateur can understand it. At the same time— TEXTBOOK ON RADIO— is a standard textbook for the technical radio student. RAD'0 Order NOW and Be Sure of Your Copy! Cloth Bound, $2.50 :-: Flexo-Leatho, $3.00 This new TEXTBOOK on RADIO is the new big brother to Radio's three best sellers "Radio's Three Best Sellers!" HOW TO BUILD YOUR OWN RADIO SET, 25c RADIO DICTIONARY, 50c RADIO FOR BEGINNERS, $1.00 Buy Them From Your Dealer or Direct From TECHNICAL BOOK CO. 130 West 42nd Street, Dept. W, New York uiyiiizeu uy TXT

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VOLUME TWO OF RADIO WORLD [Copyright, 1922, by Henaeeey Radio Publication* Corp., New York, N Y Eatered aa eecowl-claaa matter, March 28, W22, at the Pott Office at New York, N. Y.. under the act of March 3. 1879.J A Weakly Journal, Published Erery Wednesday and Dated Satard-w, by Heanauy Radfe Pat- tkabon* Corporation from Publication Office, 1493 Broadway, Now York, N.Y. T.laphonn Bryant 47M VoL II, No. 2 October 7, 1922 15c per copy, $9.00 a year Superheterodyne Receiver as Applied to the Armstrong Superregenerative DURING the past five years, considerable expert engi- neering has been directed toward finding an efficient and sat- isfactory method of amplifying radio- frequency energy at short wave-lengths. A glance at the char- acteristic curves of the present available detector tubes will show a very weak signal cannot be recti- fied efficiently or completely. In view of this, additional audio-fre- quency amplification would not be of assistance. All detector, or rec- tifier, characteristic curves indicate that the resultant audio-frequency current is approximately propor- tional to the square of the impressed radio-frequency voltage. There- fore, the efficiency of the detector decreases rapidly with decrease of signal until a stage is reached at which the detector almost ceases to Circuit By Charles R. Leutz function. Many types of amplifiers have been devised to magnify radio- frequency energy before applying it to the detector; and many have worked very well on long wave- lengths— resistance, inductance, or capacity couplings. However, to use the same method of coupling for ex- tremely high frequencies corre- sponding to wave-lengths of 50 to 200 meters, most results have been complete failures. There is a good reason for this. The low-capacity reactance existing between the structural elements of the amplify- ing tubes acts as the equivalent of a dead short circuit around the cou- pling medium and prevents a dif- ference— a potential being trans- ferred to the exterior plate-circuit. This short circuit can be elimi- nated by tuning with a parallel in- ductance, but this leads to difficul- ties in the form of complicated ad- justments and local oscillations. The French and English have con- structed special tubes with a new to reducing the internal capacity, by special design. In addition, they have designed special transformers ; but the efficient results in each case have been confined to a narrow band of wave lengths; for example. 300 to 700 meters. Any attempt to increase the ef- fective working wave-length band, particularly toward lower waves, has resulted in failure. It is obvious that if the receiver is to have a cora- ( Continued on page following) Schematic daaieu of th« Annatrong auperbaterodyae receiver fully described In thli article Digitized by VJ0O

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•4 RADIO WORLD Tho*. Cokt Night. Photographer. Illustration showing tha rear of tha panal with tha should ba given doaa ounted. Sew a. tfcu U tha baa* tubal i for whin* sacs a set. particular hook-up. Tha (Continued from page 3) mercial value a range of wave lengths from, say, 100 to 850 meters must be available with a minimum amount of adjustments and with uniform efficiency over the entire wave-length range. In December, 1919, Major Edwin H. Armstrong gave publicity to an indirect method of obtaining short- wave amplification, called the super- heterodyne. The idea is to reduce the incoming frequency which may be, say, 1,500,000 cycles (200 me- ters) to some suitable superaudible frequency which can be amplified sufficiently, then passing this cur- rent through a radio-frequency am- plifier and finally rectifying and car- rying on one or two stages of audio- frequency amplification if desired. Transformation of the incoming sig- nal-frequency to the amplifier fre- quency is usually accomplished by a heterodyne oscillator and rectifier. This action may be understood readily by referring to the wiring diagram. The primary circuit, C-l, L-l, L-2, is tuned in resonance to the incoming signal-frequency — say, 1,500,000 cycles. The secondary circuit, L-5, L-6, L-7 and C-3, is tuned in resonance to the primary circuit, the coupling between these two circuits being adjusted between L-2 and L-5. V-2 is a rectifier or usual detector tube, and V-2 with the associated parts is an external heterodyne-oscillator. V-3 to V-8 is a resistance-coupled radio-fre- quency amplifier designed to op- erate efficiency at a frequency of 100,000 cycles, corresponding to 3,000 meters, the last stage of this amplifier (V-8) also acting as a de- tector rectifier. The amplifier on the imput side is coupled to the first detector by the tuned circuits C-4, L-8 and C-5, L-9, and on the out- put side to the detectors and audio- frequency amplifier tubes. L-7 is in inductive relation to L-4. Now, assume that the heterodyne oscillator is tuned to 1,400,000 cycles or 1,600,000 cycles, either position will produce a beat frequency of 100,000 cycles. The combined cur- rents of 1,500,000 cycles and 1,400,- 000 cycles (or 1,600,000) are then rectified by the detector V-2 to pro- duce in circuit (C-4 L-8) a direct current with a superimposed 100,- 000-cycle component. This 100,000- cycle component is then amplified by V-3, V-4, V-5, V-6 and rectified by V-8 and the resultant audio-fre- quency note amplified by the audio amplifying tubes V-9 and V-10. In the case of continuous-wave recep- tion, the best method of obtaining the audible note in the phones is to employ a second heterodyne adjust- able to 1,000 cycles either side of the amplifier frequency of 90,000 to 101,000 cycles, and loosely couple this to the amplifier circuit. It is also possible to receive continuous- wave signals but producing oscilla- tions in the amplifier of a slightly higher or lower frequency than the amplifier-tuned transfer wave- lengths. Oscillations and, also, re- generative amplification can be con- trolled by the special condenser, C-18. This special condenser must obviously have a very small mini- mum capacity or it would be diffi- cult to stop the amplifier from oscil- lating. Reception of spark and telephone signals can be carried on with equal efficiency and without any distor- tion, which is odd inasmuch as he- terodyning a spark or telephone sig- nal with an ordinary regenerative receiver will result in loss of note or tone. The efficiency of rectifica- tion of the incoming signal, when heterodyning depends on the phase relation with the local current. The efficiency of the rectification is a maximum when the two currents are 180 degrees out of phase, or in phase ; a minimum when 90 degrees out of phase. In ordinary heterodyning, the ini- tial phase difference will be different for each wave train from spark transmitters, as the initial phase difference depends on the sparking at the transmitter. The frequency of the two currents are practically the same, and the length of the wave train is small compared with the time required to form a com- plete beat at audible frequencies. Different wave trains are, therefore, rectified with different degrees of efficiency and the plate current be- comes irregular. The beat frequency is high in the superheterodyne — several beats per wave train being established. The phase angle between the two cur- rents changes through a number of cycles and the initial phase differ- ence need no longer be considered. The adjustments for 1 C-W and telephony are a combination of the previous mentioned adjustments for spark and C-W reception. Bear in mind that the amplifier circuits should be damped slightly to pre- vent distortion due to maximum resonance. Th£». Cokt Night. Photographer. Photograph to illustrate how tha apparatus works in conjunction with the set in the photograph at the top of this pa» Digitized by Google

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t RADIO WORLD 5 — — — y Ba. <M» Might. of tfaa front of the ; thcnrlnf its i The present equipment being used is shown schematically in the wir- ing diagram, and actually in Figures 1, 2, and 3. The radio-frequency amplifier circuit is designed for 3,000 meters. Special attention has been paid to the effective design of the receiver circuits. L-2 and L-5 con- sist of a 180-degrees coupler and give a 180-degrees scale movement to a 90-degrees coil relation. The condenser, C-3, has shaped plates to give a straight-line wave-length va- riation. The maximum capacity of this condenser is very low and the values of inductance are large in order to develop the largest possible potential on the detector grid. In view of the fact that a loud signal is produced with only a fraction of a volt on the detector grid, the ratio of L and C is important. To keep the high-frequency resistance low, the coils are designed to have very low values of distribution capacity and the condensers are of special de- sign, having only one-tenth the re- sistance of the ordinary condensers. The inductance, L-5, is used in par- allel to C-3 to give the first wave- length the range 150 to 450 meters; and L-6 is connected in series to L-5 and both in parallel to C-3 for the second range — 310 to 850 meters. As the mechanical distance be- tween L-8 and L-9 is increased, the tuning becomes sharper and a very high degree of selectivity can be ob- tained. The output resistors, R-3, can be replaced by iron-core chokes of proper value. The resistors can also be replaced by inductances and capacities, each tuned to 3,000 me- ters and give an additional advan- tage of having the amplifier reject all frequencies but the frequency to which it is tuned. The last stage of radio-frequency amplification is coupled by the tuned transformer, L-10, L-ll. A potentiometer is pro- vided for the common grid-leaks on the radio-amplifier tubes providing a means to adjust the characteristic curves to a point when maximum amplification is obtained without chance of the amplifier oscillating. The complete equipment is built in two units each entirely shielded with 10-ounce copper. The phone cords are also shielded with Belden braid. The shields are connected to the negative side of the filament battery. To use a loop the links are taken dut at posts 8 and 7, and loop in- serted there using C-3 to tune. For long-wave reception, a large in- ductance is connected in place of L-9 for the secondary and that cou- pled to the antenna. The resist- ance-coupled amplifier will function down to 850 meters. The long-wave reception would not be possible if a tuned radio-frequency amplifier was employed. The first rectifier, V-2, and heterodyne V-l are not used, of course, for long-wave reception. Material increases in signal audi- bility can be made by inserting a variometer in the detector plate lead, at post 6, 6, tuning the plate for regenerative amplification. In place of tuning the plate, it is also possible to provide inductive cou- pling between the plate and grid of the detector, V-2, in the usual man- ner. The results obtained with this unit have been very satisfactory. The antenna used was 125 feet Jong and 50 feet high, located in New York City. On 600 meters, spark signals from NGE (Miami), NAU (San Juan), NAR (Key West), NAW (Cuba), NAP (Pensacola), NAO (New Orleans), VCE (Cape Race), and ships in the canal zone were received with sufficient audi- bility to be heard 50 feet from the telephones. On 360 meters radio- phone signals from KYW (Chicago), WOC (Davenport), WWJ (De- troit), WHB (Kansas City), WSB (Atlanta), WHA (Wisconsin) were received with the same signal audi- bility. On 200 meters, a continuous stream of 8th, 9th, 4th and 5th dis- trict amateurs were near. All these results were obtained in the late summer with the usual heavy static conditions. This data, photographs, and sche- matic drawing of this design were supplied through the courtesy of the Experimenters Information Service, 220 West 42nd Street, New York City. This firm has available for distribution complete sets of blue-prints covering the entire con- struction of this equipment. TWO IMPORTANT RADIO ARTICLES IN NEXT WEEK'S RADIO WORLD Dated October 14. On Sale October 11. Using the Vario- Coupler on a Short- Wave Regenerative Set, by George W. May. What Makes the Radio Receiver Work, by Donald Van Wyck. FULLY ILLUSTRATED WITH HOOK-UPS AND SCHEMATIC DIAGRAMS Digitized by Google

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f RADIO WORLD Radio to Play Important Role in New Aircraft Carrier, "Langley" WASHINGTON, D. C— There is a strange Naval craft cruis- ing about Chesapeake Bay. She looks something like a marine dance-hall, as her upper deck is broad, flat, and unobstructed. She does not carry the usual masts and funnels. No aerials are visible, yet this curious ship answers to the radio call NNC, desig- nated in Naval radio or signal language as "Nan Nan Cast." Being mastless, one wonders about her aerials, but there are both permanent and adjust- able aerials and radio masts which can be raised or lowered at will. She is also equipped with new and novel radio apparatus. She carries a num- ber of flyers and many kinds of flying craft. The vessel is the newly commis- sioned aircraft carrier, "Langley," built out of the hull of the old collier "Jupiter," the first Naval vessel to be equipped with electric drive. She is now making her "shakedown" or trial cruise in Chesapeake Bay under com- mand of Captain S. A. R. Doyle, U. S. N. The "Langley," named for the late Samuel P. Langley, the American sci- entist who was the first practical stu- dent of aeronautics and mechanical flight, is a veritable floating landing- field and mother ship for both aero- planes and seaplanes ; but, at the same time, she is a sea-going radio labora- tory for the study and development of radio communication between aircraft and ships. Her great flying deck, which stretches for 520 feet from stem to stern and is 65 feet wide, prevents the erection of permanent masts for radio or other purposes ; for her "top sides" must be clear for the launching and landing of her aircraft. Special tele- scopic masts have been installed amid- By Carl H, Butman ships, approximately 250 feet apart, fore and aft, which can be elevated when desired, or housed below decks when the planes are being projected into the air by the catapults or alight- ing from the air on the spacious upper deck. The masts, 50 feet in height and used primarily for the radio aerials, are controlled by hand-oper- ated gears which raise and lower them somewhat as periscopes are operated. When lowered, the aerials are un- hooked and stored below or laid along- side the palisades which guard the edges of the flying deck. The masts are elevated simultaneously after the antenna wires are hooked on. This aerial is the principal one used for long-distance communication. Auxil- iary antenna are carried aft along both port and starboard sides. These an- tenna are hung outboard on davits which can be swung in, like ordinary boat-davits, and housed close to the vessel's side when not in use. Pri- marily these antenna are used to work nearby land stations and aircraft when aloft, as they do not interfere with the operation of the landing deck. At sea, with no aircraft aloft the vessel uses its mast antenna ; but when planes are taking off and landing the auxil- iary, side antenna are used, although the masts could be raised for trans- mitting a message and then lowered. Located below decks is the usual radio room found on all men-of-war with its equipment for transmitting and receiving, generators and batter- ies. The day of a radio house on the "top side" of military ships has passed. To-day the operator on watch sits be- low instead of "on top of the world" as on merchantmen and liners. Adding a Tube-Amplifier to a Crystal-Detector Set MANY amateurs wonder if it is possible to use a one- step amplifier with a crystal set. When one is a crystal receiver and the other a tube amplifier, it would appear to the fan that it is impossible to use them together. However, experienced raidomen have proved that it can be done. According to the accompanying diagram, if the amateur purchases the necessary equipment and hooks up the mate- rial according to the circuit he will discover that satisfactory results "will be obtained. The amateur must not get overexcited and think that this is a regenerative set. It is notl Nevertheless, with this in view, re- liable signals should be secured. One drawback will be the proper up- keep of a good point on the crystal ; and if this is obtained with the proper voltages on filament and plate, signals should be heard easily. The operation has already been ex- plained; the various wave lengths are obtained by varying the fre- quency of the circuits. The alter- nating current obtained from the distant transmitting station is im- pressed on the detector of the re- ceiving set. When operating with the radio com- pass on the Langley, however, the radioman comes up on the top deck and brings his house with him. In this very important work, an original idea has been carried out by the Naval constructors; for ascertaining the po- sition of aircraft, ships or shore sta- tions, the radio-compass house, built on the lines of an elevator, is run up to the top side where it projects above the deck like a pilot house. Its oper- ator, the radioman, can raise and lower it at will, and from its location — aft on the starboard side — he can take bearings without interrupting the op- eration of planes as they land or de- part. The roof of his house, when he is "up," forms part of the deck of the flying platform when he is "down." Below in the radio room the ship has a regulation Naval 2-kilowatt spark-set for ordinary traffic work ; but there is also a 300-watt tube trans- mitter, consisting of six 50-kilowatt tubes. This set is adaptable for use either as a radiotelephone or as a tele- graph apparatus with I C W (inter- rupted continuous wave) or C W (continuous wave). For communica- tion with the aircraft in the vicinity of the mother ship, either on the sea or in the air, the 300-kilowatt set is used. This is to insure direct and in- stantaneous communication. Another feature of this unique ves- sel is the plane elevators, which raise and lower planes from the storage hold below, and the top of the eleva- tors forming part of the ship's deck when they are "down" like the radio- house roof. Fore and aft are the catapults for launching the planes, as well as the arresting gear for stop- ping them when they land. Most of the usual "top side" equipment of an ordinary ship is below the flying deck : for example, the pilot house, which is well forward, port and starboard jib- cranes for lifting seaplanes from the water, the four 5-inch rifles, and deck houses. Her two funnels project from her sides toward the stern, where they may be turned upward, aft, or down- ward to keep the smoke from the up- per deck. Great results are expected from the "Langley," the first aircraft carrier of the Navy, and many advanced experi- ments in radio communication with aircraft are planned. The lessons learned in radio and practical aero- nautical operation at sea will be incor- porated in the new aircraft carriers which the Navy will build out of two battle-cruisers scrapped by the Arma- ment Conference. Digitized by Google

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RAJDIO WORLD 7 Constructing a Radio-Frequency Regenerator By C. White, Associate A, I. E. E. RADIO-FREQUENCY regener- ation is, perhaps, a very mislead- ing and unknown thing to many; but, in reality, h is nothing more than accomplishing a double purpose with a single operation. We are just be- ginning to grasp the full realization of what may be done by means of regen- eration and radio-frequency amplifica- tion. The recent invention of Major Armstrong reveals that it is possible to accomplish critical or superregener- ation by means of special circuits which, literally speaking, keep the tube from misbehaving. Therefore, we can say that our development in the radio field consists in not only discovering new things but in perfecting our old apparatus so that certain previous troubles are cured. Such is the case of applying radio-frequency and re- generation to the same circuit. The circuit illustrated in Figure 1 is quite different from the ordinary radio-frequency amplification hook-up. The first very apparent dissimilarity is the use of a tuned plate-circuit that is regenerative; the second is the em- ployment of a crystal detector instead of the ordinary bulb type of detector. The reason for the first change is that we can obtain a slight regenerative effect with a tuned plate type of radio- frequency amplifier ; but it must be re- membered that good results are obtain- able only when the mutual coupling is kept extremely low. If, however, it is attempted to operate the set with a critical coupling between the tickler and the secondary there will develop a serious distortion of the sound waves which will very materially hamper the true reception of music, although the volume will be greater than when the coupling is maintained at a low value. From the electrical standpoint, we are not actually regenerating our signals, but we are so altering the constants of the tuning circuit that the effective resistance, or impedance, of that cir- cuit to the incoming wave will be ex- tremely low, thereby improving recep- tion from a long distance. The virtue that the crystal detector is practically noiseless in operation ex- plains fully the only basic reason for its use in the construction of this out- fit. The one disadvantage of the crys- tal has been the trouble one experi- ences in trying to find the sensitive spot, but with one stage of radio fre- quency it is quite easy to get a good adjustment. However, since we are going to employ one stage of audio- frequency amplification, the total vol- ume emitted by the detector will be sufficient under all normal conditions. While the bulb detector is by far the more efficient in operation, still the quality of the sound received through a crystal detector is much more nat- ural. A bulb detector can, however, be substituted for the- crystal ; but the amateur must remember that serious howling may develop, due to extreme- ly critical reaction owing to the fact that the detector tube reacts on the grid of the radio-frequency amplify- ing tube through the mutual inductance between the secondary and the regen- though not absolutely necessary, al- lows a more flexible control and greatly augments sharp tuning. All three coils should be constructed simi- larly and mounted so that the mutual coupling can be varied. The middle coil, or secondary, should be station- ary; and the tickler and the primary should swing in and out from it. If it is so desired, the amateur can pur- chase coils similar to the ones just described, already mounted, for a rea- sonable sum, from any radio supply store. The condensers C-l and C-2 are variable condensers of the 23-plate type, while a grid leak of one megohm and a grid leak condenser of 0.00025 microfarads will suffice. If it is de- sired to make the outfit capable of ex- tremely critical tuning, I would recom- mend that either a 43-plate type con- denser with a built-in vernier attach- ment, or a three-plate vernier con- denser, shunted around the 23-plate types, be used. I would like to call the amateur's attention to this fact : If a high value Figure 1— A circuit that it different from the ordinary radio-frequency amplification hook-up. Fully d» scribed to the accompanying- article. Drawn by C. White erative tickler element. To avoid all possible trouble of this nature, I would suggest that the amateur stick to the crystal detector in using the particular type of the hook-up explained in this article. Relative to the actual construction of this outfit, I would advise that the unit E, F, G be made up of three pan- cake type of inductances mounted in a manner similar to the mounting of three honeycomb coils. Spider-web inductances can be made up easily by cutting out a form about five inches in diameter and dividing it so as to have seven, nine, or eleven spokes. Using a circle, two inches in diameter as a hub of the wheel, the novice should cut out the spokes. Using this form he should wind on about fifty turns. Some may find it more con- venient and expedient to put on more turns and tap the same every ten turns; but this added refinement, of B-battery voltage be used with the audio-frequency amplifier tube and a small C battery having a variable voltage from two to ten be employed in the grid circuit of the tube as shown in the diagram, he will find that the net resultant amplification will be many times greater than if he had used the customary 45 volts with a U-V 201 type of bulb. Therefore, I heartily recommend that the novice get the maximum use out of his bulbs for amplifying purposes by having a po- tential of at least ninety volts applied to the plate circuit. In addition to the scientific qualities of this receiver, the price is much lower than any other type of long-distance receiver. This is true because there are no expensive variometers and variocouplers to be purchased. It is possible to make up this outfit for $15 if the amateur does not wish to use a panel type of mount- ing. Digitized by Google

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I RADIO WORLD The Radio Primer Weekly ABC of Radio for the Beginner, in which Elementary Facts and Principles Are Fully and Tersely Explained What is the grid leak? WHEN waves enter the tuner from the aerial, the grid is affected with an alternation of positive and negative waves. The flow of electrons from the filament is helped when the grid is positive, but is hindered, or prevented, when the grid is nega- tive. For our purposes, it can be considered that, when the grid is posi- w. G mo Leak- the filamant and (rid. tive, the little charges of electricity exchange places with the negative charges flying from the filament m the form of electrons. But when the grid is harboring only negative electricity, it is held a prisoner. There is no place for these charges to go. The little ups and downs of the radio waves, however, come in thick and fast, and the grid endeavors to take care of them. It has no trouble in getting rid of the positive halves because they flow over to the filament; but the negative halves remain where they are. Soon these negative charges are crowding the grid. As soon as the wave train ceases — and before the next wave train appears — the grid gets rid of these negative charges by making them leak through the most convenient hole. The grid leak is for this pur- pose. It takes care of the negative charges on the grid. Unless this is done, the action of the tube as a de- tector would be unsatisfactory if not impossible. * * * Can a grid leak be placed anywhere in the circuit, or is there a special place for this to got The grid le^1 ' ns its own place in the circuit -■ o there to func- By Lynn Brooks tion properly. If placed elsewhere in the circuit, it would not function and would render the whole set inopera- tive. * * * What effect wiU the grid have on the action of the tubet Current is normally flowing from the positive pole of the B battery to the plate across the filament and from this point through the telephone re- ceivers. If it were not for the grid, this current would not produce any sound whatsoever in the telephone re- ceivers. But the grid is keeping time changing from positive to negative and keeping pace with the alternations of the incoming signals. * * * What happens to this flow when the grid is negative? We must remember that the elec- trons are also negative. The electrons coming from the filament are repelled for the instant. When this happens the current flowing through the tele- phone receivers from the B Battery is interrupted. Since the flow of elec- trons depends, in turn, on the current. It is easy to see how this current is interrupted by the changing charges on the grid. When the grid is made positive, the electrons are attached and the space current between the plate and the filament becomes a good conductor. * * * Does it make any difference if a C battery is used on any type tube used in the circuit of the grid element of the tubef The C battery has played some im- portant parts ; but is not needed in the present type regenerative circuit. It has been used successfully in Major Armstrong's superregenerative circuit. * * * What voltage generally is employed on the filament of the vacuum tubes in general use? The voltage used for lighting the filament of the vacuum used to-day is secured by a storage battery. Some- times the dry cell is used, but it will be found that this method of lighting filament tubes is an expensive proposi- tion. Stick to the storage battery un- til something better is invented. * * * Wk0 instruments are needed for the care of storage batteriest Storage batteries need great care. Scale Storage Battery Tha asadMan at • atom gm aattsry to da- tanainod by tha sparine gravity at tib* add solution. An instrument. caBad tha "hydro—atar," ia uaad, a* shown la this diagram, to teat density of specific gravity. If neglected they will go to ruin. A D-C voltmeter or hydrometer are two instruments that will enable the radioman to keep in touch with the condition of his storage battery. The accompanying illustration shows how the hydrometer is used. These hydro- meters may be purchased in most any radio or electrical or automobile shop. * * * How does the tube function? The vacuum tube of to-day has three elements. The grid is connected to what is known as the "input" cir- cuit of the tube. The radio currents pour in through this circuit from the antennae. Since these currents are al- ternating, the little grid between the plate and the filament will be positive one moment and negative the next. In this respect, it will be kept busy changing its charge thousands of times every second. • a « Is it necessary to use storage batteries for filament lighting of vacuum tubes when working with a transmitter em- ploying tubes? When using vacuum tubes for the transmission of radiotelegraphy and radio telephony, it is not essential to have the filaments heated by battery current as it is when using tubes for receiving, as the use of low commer- cial-frequencies at the transmitting station does not effect the reception of signals at the receiving station. Fila- ment-heating transformers have been developed for filament heating. -pigitized joy Google

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RADIO WORLD 9 Why the Open Antenna Is Best for the Radio Listener THE radio art suffers, as does all new arts, from "too many ways of doing the same thing," and in no feature does this appear more than in the type of antenna used. The "radio pages" of the newspapers, the semi-technical press, even the higher- grade publications, teem with sugges- tions as to using the electric-light wires, the telephone leads, barbed-wire fences, wires strung around picture molding and the like, for picking up broadcast signals. It is no wonder that the newcomer in this fascinating field is bewildered to the point of not know- ing what to choose from this chaotic array. Let us consider for a moment the reason for all this. The unfortunate fact appears that, practically, every conductor known may be used to re- ceive signals, because the signal sent out from any transmitter sets up cur- rents in every piece of metal it en- counters, such as the metal structure of buildings and bridges, the rails of railroad tracks, and, of course, every electric light, telegraph, and telephone wire that exists above ground or even below ground. Thus it is that our problem is not in finding a conductor to pick up signals for us, but rather in choosing a good one. Now the fundamental laws govern- ing the best form of receiving antenna were worked out long ago, particularly in popular form by Dr. Austin of the United States Navy. They are simple, indeed. Here they are, expressed in nontechnical language : 1- The higher the receiving antenna, the stronger 2. Tha "height" of an antenna la tfc above around of Ita "middle point.'' X. For any particular wave-length, there la a heat over all length for the antenna. In addition, a few other simple rules may be added, such as : 4. Tha antenna should he aa far away aa pos. particularly grounded S. If it Is necessary to croee other wires, run aa nearly aa possible at right angles to these, and aa far aa you can above them. With all these rules in mind, and with other considerations which have been proven by practice, let us consider die best form of antenna for the radio novice to install in order to receive broadcast. First of all, use a single wire an- tenna. This, at least, is just as good as a four-wire antenna, or cage an- tenna, and in many cases will prove a little better. The material of the wire does not matter much. It may be bare or insulated, it makes absolutely no difference which. Copper, phosphor bronze, or brass, may be used; even galvanized iron can be used without By C. D. Wagoner much loss. Of course, it is advisable to use a good strong wire, such as phosphor bronze, so it will not break under strain. It is further recom- mended that this wire be used when- ever possible. Every retail radio store carries this stranded aerial wire, so it is always easy to get. In regard to the "height" part of the antenna. The ideal antenna would be one erected straight up and down, such as a wire suspended from a very tall flagpole. This is because the "middle point" of this wire is higher above ground than would be the case if the wire were inclined, or bent in an L shape. But, unfortunately, few of us have masts 200 feet high, and so some compromise must be sought. The answer is this: A. Run your wire from your radio room straight up into the air, AS HIGH AS YOU CAN; and then, B. Run the rest of the antenna approximately horizontally, to a point aa high aa you can find. You will then have as good an an- tenna as you could wish, so far as the question of height is concerned. This antenna is called, for obvious reasons, the "inverted L" type. If you run the upper part of the L horizontally, then the height of the middle of your wire is the height of the wire above ground. But if the far end of this wire happens to be higher than the near end, you have raised the middle point, and your antenna will receive signals slightly better. On the other hand, if you have to run the an- tenna "slanting downwards," you have lowered the middle point and the an- tenna will not receive so well. So try to have both ends of the "horizontal" part of the antenna as high as possible. If you find it possible to make one end higher than the other, by all means do so. If the far end of the antenna hap- pens to be a tree — as in many cases is the case — remember that during heavy winds the tree will sway greatly. This is likely to break your wire. One way (Continued on following page.) Radio Room of "Majestic" the World's Largest Transatlantic Liner (C. Kudel & Hortort News Photos.) The steamer "Majestic,'' of the White Star The equipment is of the beat, and the room The photograph shows tha eecond-in-charge used for takes particular pride in her radio am of the choice positions on the big L. H. Tamptta, at the C-W Digitized by Google

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10 RADIO WORLD (Continued from preceding pagt) to overcome this is to attach a pulley to the tree and bring a rope, or wire, from your end insulator over this pul- ley to a weight, so this weight can rise and fall with the movements of the tree. Another thing to remember is this: Do not allow the actual antenna-wire to come within seven feet or so of the tree branches. If very near the branches, they might touch during stormy weather, and thus "ground" the antenna; and, also, it is well to keep your antenna some distance away from any other conductor — even a very poor one like a tree. You know that even a tree may be used as a re- ceiving antenna, if you don't want to receive very far and if you are con- tented with a very weak signal. As to insulation. Although the voltage on the receiving antenna is very small, the energy is also very small and every bit of it must be re- tained. Therefore, you should insu- late the receiving antenna well. In dry weather, even a rope is good enough; but let a few drops of rain fall, and the antenna insulated in this manner becomes absolutely useless. Insulators, small ones, probably of porcelain or good composition, should be used. Electric-light knobs, suffi- ciently large — two inches in diameter at the end — are fairly good, if you cannot get the type developed by the radio concerns who have had long ex- perience in the business. So put in an insulator at the fai end of your antenna, and another where it is supported at the near end, probably by your house. Also, where the wire comes into your house, a por- celain tube should be used. Inside the house, where rain ordinarily does not come, insulation is not so im- portant, but it does no harm to run your wires on porcelain knobs even there. The' length of the antenna depends on the wave length one wishes to re- ceive, and it is assumed here that the present broadcast wave of 360 meters is the one in question. Now, there is no special length which must be used, but there is a length which is, all things considered, the best overall value. That length is 160 to 180 feet, from the far end of the horizontal portion back to the near end, and down the vertical portion to the receiver itself. Now, if you use much greater lengths, you will get much louder sig- nals, but you will find it impossible to "tune out" interference from other stations. If, on the other hand, you use much shorter length, you will get even greater freedom from interfer- ence than if you use the standard length of 160 feet; but on the other hand you will get a rather weak sig- nal. All things considered, then, 160 feet is the best value for you to use. A great many people have the idea that if they put up a four-wire an- tenna, with each wire of the four 40 feet long, they will get the desired ef- fect. Nothing could be farther from the fact. If a four-wire antenna is put up for receiving — a foolish thing to do in any case — each wire should be 160 feet long, just the same. When a wire picks up a radio sig- nal from space, it means that it has "drained the ether" at that point of just so much energy. . You can form a mental picture of the waves flowing by, like water waves on a river, and here and there a whirlpool drawing the water down to a reservoir below. So, in the vicinity of a wire which is picking up signals, the ether is "drained dry," and any other wire which is nearby has little energy strik- ing it which it can receive. Thus it is that an antenna inside, or alongside of, a steel building receives very little signal. Therefore, erect your antenna as far away as possible from any other wires, particularly grounded ones. Tin roofs, electric signs, gutters, all are very bad. Several cases have been noted where an antenna was behind a tin-roofed building, and slightly below the level of the roof, and the signals coming from a certain station, striking the tin roof first, were diverted so that the antenna got practically nothing at all. Raising the antenna on two small sticks, so that it was six feet above the level of the roof, brought in roaring signals. A similar experience was found in the case of a huge electric- light sign. Just get the idea that the metal mass casts "a radio shadow," and get your antenna up out of the shade. There are other forms of electricity other than radio waves, as you will find if you put up an antenna parallel to and near to your electric-light wires, particularly if alternating cur- rent «is used. On attempting to listen in on the radio receiver, a deafening, low-pitch, roar will be heard, this be- ing the sixty-cycle current induced in your wire from the neighboring elec- tric-light network. This can be mini- mized— not entirely removed, unfor- tunately— by running your wire at right angles to the power wire, and, also, by keeping it as far as possible above it. The same applies to tele- phone wires, though they will give much less trouble. Ordinarily, you will be bothered in this case only when "Central" rings someone. We can summarize the situation thusly : For the best possible receiving an- tenna for 360 meter broadcast re- ception, make your antenna according to these simple rules : A. Use a •ingle wire only. B. Run the vrire in the form of an Inverted L. C. Keep both end* of the horizontal part of the L a* high as yon can. If one end can be higher than the other, go ahead and do it. D. Insulate the antenna well at all points where you support it. E. Make the total length of your wire, from radio set to far end, not more than IN feat long F. Keep the antenna wire as far away as you can from tin roofs, grounded wires, gutters sad the like. In any case, be sure to have the an- tenna HIGHER than these. G. Rub the antenna at right angles to any power wires, and as near as you can at right angles to the telephone wires. If you have to choose be- tween the two, pay most attention to the power If there are any high-tension wires — that is, over 220 volts — near your home, it is absolutely up to you to treat these with the greatest respect. The best advice is not to cross these at all, but if you cannot put up an an- tenna without doing this, take the greatest care to have plenty of dry rope between you and the antenna wire when you are hauling it up and use heavy wire, well-installed, so as to be sure that your antenna will not break and fall across the power wire. If you cannot get a length of 160 feet by running up as far as you can (50 feet is about the best average height that the ordinary house or barn will provide) and then running straight out with a horizontal stretch, it will be better than nothing to run out horizontally as far as you can, and then make a turn in your line of direction for the remainder of the length. This is true only if you do not turn more than a right angle from the line. If you run across, say, 50 feet to the only tree in the vicinity, and then 60 feet more, at right angles, to some other support, you will have a fair antenna. But do not make the mistake of turning back in the same direction as you started — that does no good at all. See Figure 2. One of the most persistent errors people make is in believing that the receiving antenna has to run in some definite direction in order to pick up a certain station. Nothing could be further from the truth. Suppose you are some 50 miles from a station — WGY, for instance — and that this sta- tion is due north from you. You can run your receiving antenna north, south, east, or west, or any position in between — the signal will come in equally well in any position, as far as the angle itself is concerned. Of course, in one position it might be screened by a gutter, and not screened at all in some other direction ; but that is not the point. The point is, that direction of the antenna means noth- ing at all in reception. The reason that this misunderstand- ing exists is simply because a little knowledge is just as dangerous in radio as in other things. If the hori- zontal part of the antenna is very long. a hundred times longer than the height, under these conditions the an- tenna is strongly directional ; that is, it receives signals very strongly when (Continued on following page) Digitized by Google

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RADIO WORLD 11 (Continued from preceding page) they come from one direction and very weak when they come from some other direction. But where the length is, say, 110 feet, and the height 50 feet, a ratio of 2 to 1, the directive effect is absolutely unnoticeable. Run your an- tenna the direction that gives you the most "open view," unobstructed, to- ward your favorite broadcasting sta- tion, or in the direction of some con- venient tall tree that enables you to get the much-desired 160 feet total length, or in the direction that crosses the electric-light line at right angles. All these considerations mean a great deal to you — the consideration of what angle your antenna makes with the line running toward the broadcasting sta- tion means nothing at all. From the foregoing instructions — how to erect the best possible form of receiving antenna — it is hoped that everyone who installs a radio set will strive to forget the swarm of "freak" antennas, ranging from kites, trees and electric light wires, through picture- molding wires, bed springs, and on umbrella ribs, down to wires buried in the earth. Where no other wire is available, it is, at times, necessary to resort to these makeshifts, particularly in military circles ; but the novice need not go to these extremes, and should not. They will all work, after a fashion, and if you are an amateur, rather than a radio listener, by all means try them all and be honest with yourself as to the results you observe, but this is written for those who want a radio set for the information it gives them, not what they can do to torture it. So I repeat, forget the freaks and put up a standard type according to the best known engineering prin- ciples. There is, however, another form of antenna which is desirable under some conditions, and which is perfectly cor- rect technically. This is the so-called loop-antenna, which consists of a few turns of wire wound on a frame of some sort. This is really nothing more than a huge receiving coil. In fact, your receiver coils themselves will sometimes pick signals from a powerful station nearby. The advantage of the loop antenna is that it is very strongly directive. If it is pointed so that its plane points toward the station you want to hear, this station can be picked up, while other stations in a direction at right angles to this cannot be heard at all. Another advantage of this antenna is that it receives somewhat less at- mospheric disturbances than an ordi- nary open-wire antenna, relative to the strength of signal picked up. This is called the signal-to-static ratio. However, there is one factor to be carefully borne in mind, and that is, an ordinary loop antenna is much less sensitive than a good open-wire an- tenna. In round numbers, if you have Radio Keeps Customers Happy (U. Kadel & Herbert Ncw« Photoa.) In the fashion salon of Welly Soeurs, Parte, Franca, the radiophone la In daily use for the amusement of both the mannequin* who exhibit the styles and the customers. Following the lead set by America, radio is fast becoming popular in Europe. In this particular case, It is said to be the means of bruujinc many customers to the coe turner's shop. an ordinary antenna, 40 feet in the air, and a 4-foot loop, the latter receives about one one-hundredth as much sig- nal as the former. You have to make up for this by adding amplification in your receiving system. This is not a treatise on amplifiers. It is intended to tie' down the facts : A loop antenna requires 3 radio-frequency amplifiers added to the receiver system, before the signal is as loud as on an ordinary wire antenna 40 feet high without amplifiers. The loop antenna, of course, con- sists of more than one turn, and the more turns the louder the signal it picks up. But there is a limit to the number you can use, and this is a definite limit, not a mere "undesirable limit" as in the case of the open wire antenna and its length of 160 feet. For 360-meter work, a 4-foot loop may have about 10 turns and no more. There are definite reasons for adopt- ing a loop antenna under certain con- ditions. In the congested city districts — in apartments, for instance — it is often out of the question to erect open antennas. Sometimes" the landlord flatly forbids it. Here, a loop antenna may save the day. A factor that makes this possible is, that there is a broadcasting station, to-day, in every large city, so that city dwellers have "lots of signal" to work with and can make use of loops without adding many amplifiers. Again, it may happen that there is an interfering station that bothers you greatly when you try to receive your favorite concert. If it happens that this interfering station is at right angles to the broadcast station you want, a loop antenna will be very use- ful for you. It is very probable that some of the sets of the future will be fitted with loop antennas as a cart of the system, the receiver and other parts being de- signed especially for this type of work- ing. When this is done, radio novices will do well to make use of the loop for their work when it will actually do good. Digitized by Google

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12 RADIO WORLD Broadcasting Stations of United States and Canada Complete to Date of Going to Press WDAQ— Hartmau Rlkar Elec Co, Pa. WDAR-Lit Bros, Philadelphia. WDAS-Samuel A. Walt*, Worcester, WDAT-Dolta Electric Co, Worcaator. Maaa. WDAU-Slocum * KObouraa, Naw UNITED STATES KDKA— Wsstlnghouse Co, Ea*t Pltt»burgh, Ps. KDPM— Westinghouse Electric * Mfg. Co, Cleveland, Ohio. KB ZT— Seattle Radio Association, Seattle, Waah. KFAN— Tha Electric Shop, Moacow, Idaho. KPAP-Standard Publishing Co, Butte, Map*. KFAQ — City of San Jo**, San Jom, Calif. KFAR— Studio Lighting Service Co. (O, K. OU- «), Hollywood, Calif, 1MI Hudson Avenue. KF AS— Reno Motor Supply Co, Reno, Nov. KFAT-S. T. Donahna, Eugene, Ore*. « WuU- metta Street. KFAU Beta* Hl(h School, independent achool diatrlct of Bote* CHy, Boise, Idaho. KPAV— Cooke * Chapman, Venice, Calif. KFAW— The Radio Den, Santa Ana, Calif. KFBA-Ramey * Bryant Radio Co, Lewtaton, Idaho. KFBB— F. A. Buttrey * Co., Havre, Mont. KFBC-W. K. ArbOl. San Diego, CaHf, MM CUf Place. KFBD— Clarence V. Welch, Hanford, Calif, MS North Douty Street. KFBE— Reuben H. Horn, San Lola Obispo, Calif. KFBF— Butte School of Telegraph (F. H. Smith), Butte, Mont. KFBC— Firat Preebyterlan Church, Waah. WHAZ— Ranaaalaer Polytechnic Institute, Troy, N. Y. WIAA— Wanpaca Civic and Commerce Associa- tion, Waupaca, Wla. W1AB— Joslyn AutomobOe Co., Rochford, DL WIAC— Galveston Tribune, Galveston, Tax. W1AD— Ocean City Yacht Crab, Ocean City, N. J. WIAE— Mrs. Robert E. Zimmerman, Vinton, WAAD — Ohio Mechanics Institute, Cincinnati, Ohio. WAJT-KeUy-Vawter Jewelry Co, Marshall. Ma WAJU— Yankton College, Yankton, S. D. WBAP— The Star-Telegram, Wortham-Carter Pub. Co., Ft. Worth, Texas. WBAZ— Times-Despatch Pub. Co., Richmond, Va. WCAB— Newburgh News Print * Pub. Co, New- burgh, N. Y. WCAC— John Fink, Jewelry Co, Fort Smith, Ark. WCAD— St. Lawrence University, Canton, N. Y. (Only weather.) WCAE— Kaufman * Bear Co, Pittsburgh, W. Pa. WCAC— Daily States Pub. Co., Naw Orleans, La. WCAV— J. C. Dice Electric Co, Little Rock, Ark. WCAW— Quincy Herald and Qumcy Electric * Supply Co., Quincy, DL WCAX— University of Vermont, Burlington, Vt. WCAY— Kesselmen CDrlcafl Co, Milwaukee, Wlac WCAZ— Robert E. Compton * Co, Quincy Whig Journal, Quincy, I1L WHAG— University of Cincinnati, Cincinnati, Ohio. WH AH— John T. Griffin. Joplln, Mo, 112 Weat Sixth Street. WHAI— Radio Equipment A Mf«. Co, Daven- port, Iowa. WHAJ— Bluefield Dally Telegraph and E. K. Kttts, Bluefield, W. Va. WHAK— Roberts Hardware Co, Clarksburg, W. Va. WHAL— Phillips Jeffrey A Derby, Lansing, Mich. WHAM— University of Rochester, Rochester, N. Y. WHAN— Southwestern Radio Co., Wichita, Kans. WHAO— Frederic A. HUT, Savannah, Ga. WHAP— Dewey L. Otta, Decatur, IB, 65* Weet Eldorado Street. WHAQ— Semmes Motor Co, Washington, D. C WHAR — Paramount Radio A Electric Co, At- lantic City. N. J. WHAS— Courier-Journal and Louisville Times, Louisville, Ky. WHAT— Yale Democrat- Yale Telephone Co, Yale, Okla. WHAU— Corinth Radio Supply Co, Corinth, Miss. WHAV— Wilmington Electrical Specialty Co., Wilmington, DeL WHAW— Pierce Electrical Co, Tampa, Fla. WHAX— Holyoke Street Ry. Co., Holyoke, Maaa. WH AY— Hunt in jtc- Press, Huntington, Ind. WIAF-GuaUv A. Da Cortin, New Orleans, La, Va North Alexander Street. WIAG— Matthews Electrical Supply Co, Blr- uungham, Ala. WIAH- Continental Radio A Mfg. Co, Newton, Iowa. WIAI— Heer Stores Co, Springfield, Mo. WIAJ— Fox River Valley Radio Supply Co, Nee- nah, Wla. WIAK-^Iournal-Stockman Co, Omaha, Nebr. WIAL— Standard Service Co., Norwood, Ohio. WIAN-Chronlcle A Nawa Publishing Co, Allen- town, Pa. WIAO— School of Engineering of Milwaukee and Wisconsin News, Milwaukee, Wla. WIAP-Radw Development Corp, Springfield, Mass. W1AQ— Chronicle Publishing Co, Marlon, Ind. WIAR-J. A. Rudy A Sons, Paducah, Ky. WIAS— Burlington Hawkeye A Homo Electric Co, Burlington, Iowa. WIAT-Leon T. Noel, Tarkio, Mo. WIAU— American Trust and Savings Bank, La Mars, Iowa. WIAV-New York Radio Laboratories, Bing- hampton, N. Y. WIAW— Saginaw Radio A Electric Co, Saginaw, Mich. W1AX— Capitol Radio Co. (Paul C. Rohwer), Lincoln, Nebr. WIAY— Woodward A Lothrop, Washington, D. C. WJAB— American Radio Co., Lincoln, Nebr. WJAC— Redell Co, Joplln, Mo. WJAD-^lackson's Radio Engineering Labora- tories, Waco, Tex. WJAE— Taxaa Radio Syndicate, San Antonio, Tax. WJAF— Munaey Press, Munsey, Ind. WJAC— Norfolk Daily Nawa (Huso Publishing Co.), Norfolk, Nebr. WJAH— Central Park Amusement Co, Rockford, in. WJAJ— Y. M. C. A, Dayton, Ohio. WJAK— White Radio Laboratory, Stockdale, Ohio. WJAL— Victor Radio Corp, Portland, Me. WJAM— D. M. Perham, Cedar Rapida, Iowa. WJAN— Peoria Star A Peoria Radio Sales Co., Peorio, llL WJAP— KeUy-Duluth Co., Duluth, Minn. WJAQ— Capper Publications, Topeka, Kansas. WJAR— The Outlet Co., Providence, R. I. WJAS— Pittsburgh Radio Supply House, Pitta- burgh. WJAX— D. M. Perham, Cedar Rapida, Iowa. WJAZ— Chicago Radio Laboratory, Chicago. WD AA— Ward-Belmont School, Nashville, Tenn. WDAB— M. C. Summer A Son, Portsmouth, Ohio. WDAC— IUniois Watch Co., Springfield, in. (Weather only.) WD AD — William Louis Harrison, Central Kansas Radio Supply, Linsborn, Kanses. WD AE— Tampa Daily Times, Tampa, Fla. WDAF— Kansas City Star, Kansas City, Mo. WDAG— J. Laurence Martin, AmarUlo, Texaa. WDAI— Hughes Electrical Corp, Syracuse, N. Y. WD AJ— Atlanta A Weat Point R. R. Co., College Park, Ga. WD AK— Mine A Smelter Supply Co, El Paso, Texas. WDAL— "Florida Times Union," Jacksonville, Florida. WDAM— Western Electric Co, New York, N. Y. WDAN — Clenwood Radio Corp., Shreveport, La. WD AO — Automotive Electric Co, Dallas, Texaa. WDAP— Midwest Radio Centra] Inc., Chicago. WDAV— "Muskogee Dally Phoenix," Muskogee, Okie. WDAW— Georgia Railway and Power Cow At- lanta, Ga. WD AX— First National Bank, Centrevffle, town. WD AY— Kenneth M. Hence, Fargo, ft. D. WEAA-Fauam A Lathron, Flint, Mich. WEAB — Standard Radio Eaadpaaant Co, Fart Dodge, Iowa. WEAC— Balnea Electric Service Co, Terra Haata, Ind. WEAD— North weet Kansas Radio Supply Co, WEAF-Wastara Electric Co, N. Y. WEAG— Nichols - Henellne - Baaaett, Ede^wood. R. L WEAH— Wichita Board of Trade and 1 ■■*»■ Radio Co., Wichita, Kansas. WEAI— Cornell University, Ithaca, N. Y. WEAK— Junua B. Abercromble, St. Joaaph, Ma. WEAM— North PlaJafsasd, N. J. WEAN-Shepard Co, Providence, R. L WMAB— Radio Supply Co., Oklahoma City, OlrJa. WMAC — F. Edward Page, Fern wood, Caxoooria. N. Y. WMAF— Round HlDa Radio Corp, Dartmouth, WMAJ— Drovers Telegram Co, Kansas City, Ma. WNAC— Shepard Storeo, Beaton, Maaa. WOAI— Southern Equipment Co, San Antonio, Tex. KDZA— "Arixona Daily Star," Tuacon, Arixona. KDZB — Frank E. Siefart, BakersvUla, CaL KDZD— W. R. Mitchell, Los Angeles, CaL KDZE— The Rhodes Co., Seattle, Washington. KDZF— Automobile Ouh of Southern California, Los Angeles. KDZG— Cyrua-Peirce Co, San Francisco, CaL KDZH— "Fresno Evening Herald," Fresno, CaL KDZI— Electric Supply Co, Wena tehee, Waah. KDZJ— Excelsior Radio Co, Eugene, Oregon. KDZL— Rocky Mountain Radio Corp, Ogden, Utah. • KDZM— E. A. Houingworth, Centralis, Waah. KDZK— Nevada Machine A Electric Co, Reno, Nev. KDZQ— William D. Pyle, Denver, Colo. KDZP-Newbery Else Corp., Los Angeles, Calif. KDZR — BeUingham Publishing Co, BalHnghetn, Waah. KDZT— Seattle Radio Association, Saattle, Wash. KDZV— Cops A Cornwall Co., Salt Lake aty, Utah. WKAA— Republican Times and H. F. Paar, Cedar Rapida, la. WKAC— Star Publishing Co, Lincoln, Nebr. WKAF-W. S. Radio Supply Co, Wichita Falls, Tax. WKAD— Charles Looff, East Providence, R. L WKAG— Edwin T. Bruce, M. D, Louisville, Ky. WKAH— Planet Radio Co, West Palm Beach, Fla. WKAJ— Fargo Plumbing A Heating Co, Fargo, N. D. WKAK-Okfuakee County Newa, Okemah, Okla. WKAL— Gray A Gray, Orange, Tex. WKAM— Adam Breeds, "Daily Tribune," Hast- ings, Neb. WICAN— Alabama Radio Mfg. Co, Montgomery, Ala. WKAP— Flint, Dutee Wilcox, Cranston, R. I. WKAQ— Radio Corporation of Porto Rico, San Juan, P. R. WKAR— Michigan Agriculture College, East Lansing, Mich. WKAS— L. E. Lines Music Co, Springfield, Mo. WKAT— Frankfort Morning Times, Frankfort, Ind. WKAV— Laconla Radio Club, Laconia, N. H. WKAW— Turner Cycle Co, Beloit, Wis. WKAX— Wm. A. MscFarlane, Bridgeport, Conn. WKAY— Benau College, Janesvtue, Ga. WKAZ— Landaus Music and Jewelry Co, Wilkes- Barre, Pa. KDYC— Herald Publishing Co, Klamath Falls, Ore. KDYS— The Tribune, Inc., Great Falls, Mont, — Djgjfeed by ■Google

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RADIO WORLD IS ( Continued from preceding tag*) J>YW — Smith-Hughes A Co., Phoenix. Aril. BYX — Star Bulletin Publishing Co., Honolulu. X. H. LDYY — Rocky Ml. Radio Corp., Denver, Colo. VBAC — Republican Publishing Co., Hamilton, Ohio. VBAQ — Myron U Harmon, Y. M. C. A., South VBAV-Tm Emor * Hopkins Co.. Columbus, (VBAW- Marietta College, Marietta. Ohio. W" AX— John H. Stanger, Wukes-Barre, Pa. IVBAY-^ABurtcm Tolaphono A Tslegraph Co., Now York. TOAM Oraaaa«bur«. S. C WCAX-Raib Elactrle Co., Washington, D. C. WHAW-Pum Electric Co., Tampa, Fla. WLAB — George F. Grossman, Carroll ton. Mo. WLAC — North Carolina State Collar,*, Raleigh, N. C WLAO- Arvaaette Radio Supply Co., Hastings, Nob. WLAT— Johnaon Radio Co, Lincoln, Nob. WLAG — Cutting and Washington Radio Corp, WLAH- Samuel Woodworth, Syracuae, N. Y. WLAO— Waco Electrical Supply Co., Waco, Tea. WLAK — Varmont Farm Machlna Co, BaOaws Falls, V*. WLAL— Tulea Radw Co., Tulaa, Okla. WLAM — Morrow Radio Co., Springfield, Ohio. WLAN — Putnam Hardware Co., Houlton, Mo. WLAO— Anthracito Radw Shop, Scran ton. Pa. WLAP-W. V. Jordan, Louisville, Ky. WLAQ — A. E. Shilling, Kalsmsioo, Mich. WLAR— Mlckal Music Co, Marahalltown, Iowa. WLAS— Hutchlnaon Radio Co., Hutchinson, Kan. WLAT — Charisa C Bosch Co, Burlington, Iowa. WLAX- Putnam Electric Co., Green castle, lad. WMAH — General Supply Co, Lincoln, Nebraska. WMAM— Beaumont Radio Equipment Co, Boau- WNAL-R. J. Rockwall. Omaha, Nebraska. WAL— McCook Army Station, Dayton. WB A— Marshall- Carkan Co, Toledo, Ohio. ' WBZ— Westraghouse Co, Springfield, Mass. WCI Philadelphia WCJ — A. C Gilbert Co., Now Haven, Conn. WCX-Detroit Free Press, Detroit, Mich. WDM— Church of the Convent, Washing too, D. C. WDT-Ship Owners Radio Co., New York City. WD Y— Radio Corp. of Amor, Rosalia Park, N. J. WD W— Radio Construction Co., Washington, D. C WGH— Light and Water Power Co, Montgomery, Ala. WGI— Amar. Radio A Reaaarch Corp., Modford Hillside, Mass. WCI Thomas J. Hewlett, Philadelphia. WGM Georgia Railway A Power Co, Atlanta, Ga. (Atlanta Constitution.) WCY-Gaasral Elec Co., Schenectady. N. Y. WHA-Uahrarslty of Wisconsin, Madison, Wis. WHK-Warren R. Cox, Cleveland. WHN-Brooklyn, N. Y. WHQ-Rochestsr Times, Rochester, N. Y. WHU-Wmiam B. Duck Co, Toledo, Ohio. WHW-Stuart W. Saeley, Eaat Lansing, Mich. WFO-Rlksr Kumler Co, Dayton WJH— White and Borer, Wash tartan, D. C. WJK-Ssrrice Radio Equipment Co, Toledo, Ohio. WJX-De Forest Radio Co, New York City. WJZ-WsstJngbouse Co, Newark, N. J. WKB-Swseney School Co, Kansas City, Mo. WLB— University of Mhm, Minneapolis, Minn. WUC— Hamilton Mfg. Co, Indianapolis. WLQ-Ualtad States Army, Fairfield, Ohio. WLW— Crosley Manufacturing Co., Cincinnati. WMH— Predalon Elec Co, Cincinnati. WNO-Wlrelasa Tel. Co. of Hudson County, N. J. WOC-Kariewa Radio Co, Rock Island, 111. WOH— Hatfield Elsctric Co., Indianapolis. WOK-Ptas Bluff Co, Pine Bluff, Ark. WOO-Wsstern Radio Co., Kansas City, Mo. WOR-L. Bamberger A Co, Newark, N. J. WOS-Mo. State Marketing Bureau, Jefferson Oty, Ho. WOU -Metropolitan Utilities. Omaha, Neb. WOZ-Pslludium Printing Co, Richmond, Ind. WOB-C. D. Tuska A Co, Hartford, Conn. WPB- Hamilton Elec. Co, PltUburgh. WWC-Doron Bros. Elec. Co, Hamilton, Ohio. The busy broad- casting station WGAM, Orange- burg, South Car- olina, one of the best - equipped broadcasters in the South WRl — Union College, Schenectady, N. Y. WRR— Dallaa Texas, Dallas, Texas. WRW— Tarry town Radio Research Co, Tarry- town, N. Y. WSZ— Marshall- Gerkan Co, Toledo, Ohio. WVP— United States Army, New York City. WW J — Detroit News Co, Detroit, Mich. WAAC— Tulane Unlveraity, New Orleans, La. WBAD-Starlmg Elac Co, Minneapolis, Minn. WBAE— Bradley Institute, Peoria, 111. WBAH — Daytasi Co, Mhwioapolls, Minn. WBAM — B. Rennyesn, New Orleans, La. 1 XAD— Thomas Giffen, Pawtucket, R. I. 2 IA-Jersey Review, Jersey Oty, N. J. 2 XJ— American TeL A Tel. Co, Deal Beach. N. J. 4 CD— Carter Electric Co, Atlanta, Ga. 5 ZU— State U Diversity, Austin, Texas. S UX— Radkmrt Store, Akron, Ohio. S YO— Ohio State University, Columbus. • BYV-Cohimbus Spec Co, Columbus. • YY— State Unlveraity, Lincoln, Neb. It J— Robert F. Farnum, Pawtucket. R. I. KDN— Meyberg Co, San Francisco. KFC— Northern Radio A Elac Co., Seattle. Wash. KFU— Precision Shop, Cridley, Cal. KGB— Edwin L. Lord—. San Francisco. KGC-HamOton Mfg. Co, Hollywood. Cat KGF— Pomona Fixture Co, Pomona. Cal. KHO— Louis Waamar, Seattle, Wash. KIZ— Reynolds Radio Co, Denver. Cole. KJ J— Radio Shop. Sunnyvale, Cal. KJO-C. O. Gould, Stockton. Cat KJR-Vincent L Kraft, Seattle, Wash. KJS-Bibla Institute, Los Angeles, Cat KLB — J. J. Dunn A Co, Paaadena, Cat KLP-Colln B. Kennedy, Los Altos, CaL KLS— Warner Bros, Oakland, CaL KLX— Tribune Pub. Co, rk.t,t—j c«l. KNI-T. W. Smith, Eureka, California. KNX-Electrlc Lighting Supply Co. Los rtagalss KOC— Western Radio Co, Lee Angelas. KOJ— University of Nevada, Reno, Nov. KOV-Doubleday Hill Electric Co, Pittsburgh. KQI — University of California, Berkeley. CaL KQI — A mo A. Khige, Los Angelas. KQW-Charies D. Harrold, San Jose, Cal. KTW— First Presbyterian Church. Seattle, Wash. KUO— Examiner Printing Co., San Francisco. KVQ— J. C Hobrecht. Sacramento, Cal. KWG— Portable Wire'cs. Co.. Stockton, Cal. KYF— Thearle Music Co., San Diefo, Cal. KYI— Bakersfiald Californian, Bahersfield, CaL KYJ— Loo Meyberg Co, Loa Angelee. KYY— Radio Shop, San Francisco. KYW—Westtaf bouse Co, Chicago. KZC— Public Market and Don't Stores, Seattle. KZM— Preston D. Allen, Oakland. CaL KZN— Desert News, Salt Lake City. Utah. KZV— Wenatchee Battery A Motor Co, Wenat- chee. Wash. KZY— A-P Radio Supplies Co.. Oakland. Cal. KFAY-W. J» Virgin Milling Co, Central Point. Oregon. KFBH— Thomas Musical Co.. Msrshneld. Oregon. KFBJ— Boise Radio Supply Co., Boise, Idaho. KFBK— Kimball-Upson Co, Sacramento, Calif. KFBL— Lease Brae, Everett, Wash. KFBM— Cook A Foster, Astoria, Oregon. KFBN — Borch Radio Corp, Oakland, CaL KFBQ— Savage Electro Co, Prsscott, Arts. KFCB-Nielaan Radio Supply Co., Phoenix. Arm. KFCC— Auto Supply Co, Wallace, Idaho, KFCD— Seism Electric Co, Salem. Oregon. KFDB — John D. McKee, Lombard A Ksamsy. San Francisco, CaL KPAV— Cooke A Chapman. Venice. California. CANADA CJCU-Manitoba Free Press, Winnipeg, Man. CHCA— Radio Corporation of Vancouver, Ltd, Vancouver, B. C CFAC— Radio Corporation of Calgary, Ltd, Cai- gary, Alta. CKCK-C. Melrose BeU. Regina, Seek. CHCF-G. Melrose BeO, Winnipeg, Man. CJCE— Vancouver Sun. Vancouver, B. C. CKCD— Vancouver Daily Province, Vancouver. CXCE-CanadUa Indspe. TeL Co, Toronto, Oat. CFCF-Marconi Wirsiass-Tslegrsok Co, MontreaL CFCA— Star Publishing A Printing Co, Toronto. CHCB— Marconi Wireless- Telegrsph Co, Toronto. CFCB Marconi Wlraless-TaUgraph Co, Vancou- ver, B. C CJNC-Tribune Newepaaer Co, Winnipeg, Man. CJCD-T. Eaton Co, Ltd, Toronto, Oat. CKZC— Dalton Radio Eng. Co, Winnipeg, Man. CHYO— Northarn Elactrle Co., Montreal. Owe, CFCE— Marcooi Wireless Tslagraph Co, Halifax. CHCB— Marconi Wireiees-Tekgraph Co, Toronto. CJBC— Dupuis Frame, Moatraal, Qua. CHVC— Metropolitan Motors. Toronto, Oat. CJCA— Edmonton JournaL Edmonton. Alta. CJa-McLaan. Holt A Co, Ltd, St. John, N. B. CHIC — I. R. Booth, Jr, Ottawa, Out. CHCC— Weetara Radio Co, Calgary. Alta. CFYC— V. W. Odious, Vancouver. B. C. CKAC-La Proses Pub. Co, Montreal. Qua. CHBC— Albertan Pub. Co, Calgary, Alta. CFPC— International Radio Development Co., Fort Frances, Oat. CJGC— London Free Press Printing Co, I nnrlrai. Oat. CKOC— Wantwortk Radio Supply Co, Haaaaton. Out. CJCN— Simons, Agaew Co, Toronoto. Oot- CJCB-J. a Bennett, Nelson. B. C. CJCS— Eastern Telephone A Tetr graph Co, Hali- fax. N. S. CKQC-Radio Supply Co.. London. Ont. CHCS— London Radio Shoppe. London, Ont. CISC— The Evening Telegram. Toronto, Ont. CKCS— The Bell Telephone Co.. Montreal. Quo. CFTC— The Bell Telephone Co, Toronto. Ont. CJCF-The News Record. Ltd, K tchrner. Ont. CKCR-Jonet Electric Co, St. John. N. B. CFCH— Abitibi Power A Paper Co, Iroquois Fells. CFCN-W. W. Grant Radio, Ltd.. Calgary, Alta. CHCX-B. L. Silver. Montreal. P. Q. CFCI-Motor Products Corp, Walkrrville. Ont. CKKC— Radio Equipment A Supply Co, Toronto. CKUC— Can. National Railways. Toronto, Ont- CHFC-Joha Millea A Sons. Ltd.. Toronto, Ont. ■"Digitized by Google

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14 RADIO WORLD Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengths for the Busy Reader. FIRST radio dramatic critic! "Banco," the new comedy by Clare Kummer and Alfred Savoir, which William Harris, Jr., is presenting at the Ritz Theatre, New York, is the first play to be reviewed by radio. The criticism was sent from WJZ, Newark. The new department is in charge of Miss Brain- ard, now dramatic critic in addition to her other duties as entertainer for the million or so radio devotees in the Eastern States. WJZ expects this new feature, to be presented weekly, •will rival in popularity Bedtime Stories and other standard ieatures. * » » A series of talks on "Thrift" will be delivered by prominent savings bankers from WJZ. The first speaker is Victor A. Lersner, comptroller of the Williamsburg Savings Bank, Brook- lyn, and president of the New York Savings Bank Associa- tion, who will tell "How Savings Banks Help Homebuilders. » * * Tbe new radio station in China calls for the construction of four wireless stations. One in Shanghai is to be larger than any now in existence in this country. Completion of this sta- tion will mean direct communication between the United Spates and China. » ♦ * Radio inventions are keeping tbe United States Patent Office busy. Thousand of minds are at work on radio problems. Con- sequently the patent-office examiners who handle the radio applications have more work than they can conveniently take care of. The office is swamped. Nothing is being done to re- lieve the condition and the art is suffering as a result. It is about time the force of examiners on this particular job was more than doubled. ^ The extended fall program of WGY is now effective. There 'will be four programs a week— on Monday, Tuesday, Thursday :and Friday evenings— with an extra program on Friday nights -at 10.30, Eastern Standard time. The gentler members of the iradio audience will be recognized daily at 2 P. M., when short talks expressly for women will be broadcast. * * * Lieut.-Colonel A. S. Rowan, U. S. A., who carried the famous "Message to Garcia," twenty-five years ago, when the United States was fighting for Cuban liberty, has been rewarded with a special Congressional medal. Today, perhaps, such a message as that which made Colonel Rowan famous would be sent by radio. C W. Horn, formerly in charge of the Westingbouse Radio Service Department, has been appointed to take charge of all radio operations of that company in place of L. R. Krum who has resigned to become manager of the Erner Hopkins lUec- tric Co. of Columbus, Ohio. Mr. Horn has been interested m -radio for the past thirteen years and knows every phase ot radio development. His experience on ships has been from the -time very few vessels were equipped with radio, until the recent years when every vessel sailing the seas has its radio equip- ment. # , , Following a satisfactory radio test Lieutenant Walter Hinton, American aviator flying from New York to Rio Janeiro, has started on another leg of his flight. His seaplane ' Sampaio Correia II.," is working perfectly, the new engines recently installed functioning in good^order. Many cities of this country are turning toward radio as a •convenient medium for license-fee payments. Cleveland has passed an ordinance requiring a 50-cent fee and an examination of the installation by city inspectors. Newark is considering a fee of $1, and other cities are taking up the idea. Amateur •operators look with great disfavor on such schemes, for the Board of Fire Underwriters take care of the electrical safety of the installation, while the Government licenses and regula- tions control adequately the transmitting apparatus. * * » Protest has been made in the House of Commons to defeat the plan of Postmaster-General Kellaway against granting to a combine of instrument makers for two years the right of wirfle-sg broadcasting in England, and a monopoly of the sale of receiving instruments. The plan, if adopted, will exclude American and other foreign-made wireless apparatus. Captain Wedgewood Benn, Member of Parliament, said broadcasting should be considered as a supplement to newspapers. He de- flared it marked the biggest development in the dissemination of information since the invention of the printing press. It was not right, he argued, that the development of radio broadcasting should be left in the hands of a combine. * * * Broadcasting station WOR is to have a short story contest. Anyone may enter this contest. The stories may be on any subject, the only condition, being that they should be read in not less than ten minutes nor more than twenty minutes. The contest will close October 30. The prize-winning story is to be read by its author from the WOR broadcasting station. The title of the story and the name of the author will be printed in the radio program and also announced by radio. The judges are to be selected from men and women of Newark interested in literature. All manuscripts should be addressed to J. E K., care of L. Bamberger & Co., Newark, N. J. The prize-winning story will be read from WOR on November 14. » * * Secretary of State Hughes returned aboard the battleship Maryland from Rio de Janeiro, where he attended the open- ing of the Brazilian Centennial Exposition.. He declined to dis- cuss the Turkish war, but said that he had been kept in touch, in a wonderful way, by radio, with the affairs of his office, while at sea. Lord Hambledon as an "An- nouncer" at Marconi House, London (C. International Nowsreel I'hotos) England's first "radio mus'c&lcs" have met with great appreciation by thousands who have turned to this form of entertainment. A radio pro- gram is broadcast from the Marconi House, London, to hospitals equipped with receiving; sets, so that patients may enjoy the music Lord Hambledon is photographed at the microphone of a radio-transmit- ter asking all listener* to aid the hospitals. This microphone carries the voice vibrations to the radio telephone-transmitter, where it is hurled into space Digitized by Google

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RADIO WORLD 4 Radio and the W Ollian Crystal ' D. lector THE average reader may wonder that a woman will take more than passing interest m such an apparently prosaic thing as police broadcasting; but when I read of the wonderful transmitting that had been installed for the police department of our big city of New York, I simply had to be the_ first of my sex to give it the onceover. Well, th ere is nothing in all the world just like it; and I really believe that radio will do more to sup- press crime than any other element that has been brought to the service of humanity. * » * In the first place, it is the one thing that will put the fear of God into the heart of the bandit, the pick-pocket, the hold-up man, and all others of their criminal ilk who have been having a long and hearty laugh at the law's expense. It is going to be impossible, in the near future, as Police Commissioner Enright declares, for any criminal to get beyond radio's clutches. Taking the personal element into consideration, the average criminal may outwit the police ; he may slip through their clutches ; he may even turn his weapons of destruction on officers of the law and kill them. * * * But radio he cannot escape; neither can he wreak its destruc- tion. Its penetrating force is faster than the criminal's fleeting. In no way can he outstrip it There is no hiding from it. He may — and I doubt if he can — make his way to the ends of the earth ; but the wonder waves of the ether will ferret him out. There is no place too small for them to penetrate — no corner too dark for their unrelenting eyes. * * * They told us that prohibition would empty the jails and the pene- tentiaries. I have my doubts. But I do most sincerely believe that radio, within the next decade, will prove to so many hardened crim- inals that the life they try to lead is so hopeless, they will turn to better things. Watch and see if I am not right. * * * I have been asked to give my opinion on the quality of the broad- casting programs of to-day; also, what I think of the proposed payment of royalties on copyrighted music that is being sent over the ether. While I am discussing more serious things, I may say that, in my opinion, we are receiving unusually good programs from all the broadcasting stations, considering the great amdunt of material that is being sent out I know how easy it is to criticize and tear down; how difficult to construct. And whenever^ I hear adverse criticism regarding people or concerns that are trying their best to please, I always put myself in the place of the criticized and ask if I could do any better. * * * That the broadcast programs have improved cannot be denied. They are at least one hundred per cent better than those of last spring. The selections are more varied and interesting; and the method of sending them so that the various stations will not conflict is a great step forward. * * * The operator of one of the biggest broadcasters in the East told me the other day that every station is trying hard to make still further improvements and to arrange programs that will be still more varied and attractive. Thousands of letters offering all man- ner of suggestions are being received by every broadcasting station, and these letters are not being taken lightly. Every worth-while suggestion is given the attention it deserves. And I know, that an effort is being made to secure better artists. * * * There is no doubt that the matter of royalties is — or will be — satisfactorily adjusted. I am told that, in another column of this issue of Radio World, the matter is presented from its latest news angle. The big broadcasting companies are not going to be nig- gardly regarding royalties. They want to be fair and generous. The only problem to be solved is how the royalties shall be ar- ranged. That was one of the greatest complexities that beset the moving-picture industry. » * * You will gather from all this that I am very much of an optimist so far as radio is concerned. Of that there can be no doubt. I am doubly optimistic. I believe in radio as one of the greatest bless- ings that ever came to humanity, and from a two-fold point of view ; firstly, as a great commercial advantage ; secondly, as the greatest form of entertainment that the world has ever known. * * * There is absolutely no limit to the entertainment that radio will bring us and there is no possible limit to which that entertainment may be carried. He of the remote hamlet and the sailor on the high seas will some day sit close to the city folk and hear some unborn Caruso sine. And when the next President of the United How a Singer Sends Her Voice Over the Ether - € Miss E* telle Taylor, soprano of "Thorns and Blossom*," is photographed slngtag for radio. Her voice is directed at the horn which connects with a microphone transmitter. In turn, the microphone deliver* her voice to the radio transmitter which throws it on the air. The mechanism of the microphone Is similar to that of the telephone transmitter. The horn assists in picking np the music of the piano, and blends It with the singer's voice. It is all very simple, but the great wonder of It ia how this music Is carried many thousands of miles without a flaw. States is elected, that news will reach the remotest perlieus of the South Sea Islands almost as soon as it is known in Chicago. * * * Miss Mary Hope, Atlanta, Georgia, writes to ask if I will help her to solve several hook-ups for a prize contest. Well, Miss Mary, that hardly would be fair. Why not go to it on your very own. You will be better satisfied in the long run. But, send me the hook-ups and let me see what I can do with them. * * » Mrs. H. J. S., Elmira, New York: If you are in doubt regard- ing your set, write our technical editor. He will give you the most expert advice and will publish a diagram, if that is necessary, to show you how to set things right. * * * Carrie P. Y., Pendleton, Oregon : It is impossible to say how many women are employed in the factories turning out radio appar- atus in this country. I do not believe that this has been made public as yet — I have been too busy with other radio matters to find out. However, there must be a great many. I understand that women are particularly adapted to certain branches of radio manufacturing. * » * Miss Carrie F., Montgomery, Alabama writes me that she caught station WAFYZ, and wants to know what it is. N> such place, my dear. Some mistake somewhere. There are no stations with five call letters. * » * A St. Louis girl writes that a friend has presented her with one of those miniature sets you read about. Hers is in a case made to resemble a prayer book. I wrote her that her young man is one of those bashful things who hasn't the courage to ask her if she goes to church. Thinks he'll find out anyhow. Digitized by Google

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16 RADIO WORLD The Week's Important Radio Even F (C. Kadel ft Herbert News Phcrtoa.) Here is a man with a now job! He is a radio critic. His duty is to check up and keep tabs on all the broadcasting from WJZ, Newark, N. J. . (C. Underwood 4 Underwood. N. Y. ) Paul Coatee, Chicago radio amateur, and Miss Beulah Milburn, also a fan. Mr. Coates recently caused some ripple in radio circles with a superregenerative circuit built by himself. With a three-foot loop, he tuned in Newark, Schenectady, Atlanta and Kansas City. k^ni^l^sm^sm^sm^sm^B We seldom to see hi t station Ion actual ma the hums dreds of ■ of the ra which ap| graph ta 1 by the 1 mat, Wa i <v^aanee vast impa who need I Ann Penn wsjr'i pop stars (ri| fan. N«9 •ays, radi light. Sh in her ho antenna graph w Penningti gives a i placing of speaker • to IC. (C. Kadel & Herbert News Photos.) Radio amateurs have waited long; for a < lighting of the filaments of their tube lights have a supply of alternating cur been to adapt this current to the light! kept charged, and most every radioman for such work." The accompanying; pho at Columbia University, with a set m makes use of the house current for li check up the voltage. The coils which are indicated by 2. The receiving set I vacuum tubes used as amplifiers. • home. These bulbs are used hare to aid force for filament use. Toy transform, the voltage down to that recommended I heard In the phones. Digitized by VJfQOgrc '

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vets Picked up by Busy Photographers W^ajnt '•■ikltkt chief • hfliasllng '**•.»») that to, the * m take orer h» **e hft. to if itii * * to OSae Dafwt- D. C It* to the n«| at — ther and saeft which an of ^■■Ajtowr 4aad : aaad a Mt tasuBed , a* bat eractad the ■ ma?. Tka Mas. It ban al tka 1Inuro*Uon&l Ncftn-nal Photo) Tka radio oparatar at Marcoai Houaa, London, broadcasting isrfermatioa tkat ba to recatvmg from airplane pilota during a night around tka British Moo. Tka Sight waa oaa of tka meet I ever "staged" In Europe, a aeon of "boats" centaenag. Eack waa aaaajpad witk radio and kapt in touch with tka tr an unit ting apparatus hi tka photegraph. aald ii I tka trouble attending tka t houses tkat ara wb-ad for atoctrlc uency, tka nuh problam has tabaa. Tk* storage battery moat be laa: "Can I ntilbta the bona* current Mr. J. C Acovoa, electrical engineer eliminated the storage battary. He 1 to an A-C voltmeter used to >t port in tbto particular circuit S_ 4 ara tka detector tub**, and S the ■let tilt bulbs to) general uaa in the km reducmg tka voltage to tk* required a strong (C. IkW 4 Mr. A wee's method tkto bum waa Realising the entertaining value of tka New York, Installed an audit for tka New York, Installed aa outfit for the benefit of the this regenerative sat and twa stages af of tka Hab.ee Orphan m hundred erphaas there. With results are highly sattofactary. Digitized by Google

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5 RADIO WORLD MICROSTAT VERNIER RHEOSTAT The most sensitive filament control and- quickest, easiest tuned. This microstat has ten times the possi- bility of exact filament adjustment as over the ordi- nary wire rheostat. It eliminates grating and interfering noises, has single knob adjustment and is far more durable being made of better material with greater care. This microstat takes up less room on the radio board, is neat and compact. The exact calibrations of the microstat are due to the gradual entering of two points into the resistance material of our own com- position which gives us exacting and most minute measurement of current to the filament as the oper- ator brings the two points together or separate's them through the screw handle. Order through your dealer or delivered to any part of U. S. $1.40 ■ 9 «T * # H r > III I II 1 ii MICROSTAT COMPANY WILLIAMSPORT, PA. Dealers, write for quantity prices Eliminate Storage Battery Equip your set with the famous dry cell tube Use Your Present Socket Wiring changes are unnecessary when you use the Patent Applied For SUNECO TUBE ADAPTER TO USE Place tube in adapter, put adapter in socket. The tube circuit is automatic- ally adjusted to con- form to set. r1 $1.50 each Sun Equipment Company 67 Exchange Place New York, N. Y. Broadcasters Will Pay Royalties for Copy- righted Music MORE than one million dollars per year additional revenue is expected to enrich the coffers of the American Society of Composers, Authors and Publishers, says "The Clipper," New York, when final ar- rangements are completed between the so- ciety and various radio broadcasting-stations that perform copyrighted music for profit, take out performing rights licenses and pay an equitable fee for such rights. The most definite step taken by the society to license the radio stations was on Wed- nesday, September 20. when a conference was held at the A. S. C & P.'s rooms, between various radio representatives and organizations interested in copyright and the rights of such copyright owners. All of the representatives of the leading radio inter- ests acknowledged the rights . of copyright owners to collect a fee when their works were performed for profit, and the sugges- tion by E. C. Mills, chairman of the execu- tive board of the Music Publishers' Protec- tive Association, who presided at the con- ference, that $5 per day be a minimum fee for each station, graduating up to a larger fee, was favorably received by those repre- senting the important radio corporations. At this rate, the tremendous amount that will be paid the society by the radio stations will easily reach the million-dollar mark. Many interesting questions were brought up at the conference, the stenographic re- port of which covers more than 100 pages and copies of which will be available to those interested as soon as they can be printed and bound. Most of the questions that arose were made by the radio men for points of information, and practically all of them were answered by E. C. Mills, who was later warmly congratulated. Those present at the conference were : American Society of Composers, Authors and Publishers — Nathan Burkan, general counsel, and J. C. Rosenthal, general man- ager. Authors League of America — Mr. Williams, president, and Eric Schuler, vice- president. Music Industries Chamber of Commerce— Alfred L. Smith, general man- ager. Music Publishers' Association of the United States — George Fischer, president, and Alfred L. Smith, secretary. Depart- ment of Commerce, United States of America — Arthur Batcheller, Radio Inspec- tor of Second District. American Tele- phone and Telegraph Co. — A. H. Griswold, S. L. Ross and C. H. Fuller. Radio Cor- poration of America — J. C. White, and Ira J. Adams, counsel. General Electric Com- pany— H. E. Dunham, counsel, and M. P. Rice, in charge of WSY station. Westing- house Electric & Manufacturing Company — William E Easton, vice-president; Calvert Townley, assistant to the president, and C. B. Popenoe, of WJZ broadcasting station. G. Shirmer, Inc.— O. G. Sonnecke, National Radio Chamber of Commerce — Mr. Lewis, secretary. Music Publishers' Protective Association — E. C. Mills, chairman of the executive board, presiding at the confer- ence. Radioisms A RADIO Beginner is a man who spends $90 on parts to build a $19 set. A Radio Fan is a man who believes that God made the air for broadcasting. An Amateur is a man who is convinced that the devil invented broadcasting merely to fill the atmosphere with noise to smother the sweet sounds of the dah- de-dah. The Dah-de-dah is a peculiar bird who is never satisfied with QRK, but is ever looking with longing eyes on DX. He abhors ORN, but manages to stand it, vet QRM. particularly from broadcast- ing stations, brings tears of anger to his eyes.— "The Globe," New York.

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RADIO WORLD If California Leads in Broadcasting Stations Service Continues in All but One State By Washington R. Service BROADCASTING still continues WLAX— Greencastle Community in all but one State in the United Broadcasting Station (Putnam Elec- States, notwithstanding pessimistic re- tric Company), Greencastle, Indiana, ports from some quarters that this WLAS-yHutchinson Grain Radio service, which is likened to a fad, is Co., Hutchinson, Kansas, falling off and likely to collapse. On WPAN— Levy Bros., Dry Goods September 21, there were 510 active Co., Houston, Texas, broadcasting stations, according to a WMAG — The Tucker Electric Co., survey by the Radio Section of its Liberal, Kansas, limited commercial stations, operating The Ust by States is as foUows . °n^,, ,meter?' , , . Numb* of Bm.dr.iHng Stations by States on The list of broadcasting stations September n, its published on pages 12 and 13 of this California 66 issue of Radio World is a complete ^kio 34 record record of licensed stations in Pennsylvania ° .!!!!!!!!!!!!!!!!!!!!!!! ! 27 the United States and Canada, alpha- Texas !!!!!!!!!!!!!!!!!!!!!!!!! 25 betically arranged. It has been Washington 23 brought up to date-every station ^"ol^ . ! ! ! I ! '. ! I ! : : : : : ! : : ! ! : : ! ! ! ! ! ! ! ! 20 officially reported from Washington iowa 20 received up to the time of going to Nebraska 17 press is included. All new stations Oregon IS are published in Radio World from Minnesota '.!!!!!!!!'.!!!!'.!!!!!!'.!'.!!'' 12 week to week, as soon as received Indiana ............................... 12 from Washington. Massachusetts 12 California still leads with 66 sta- New'fefse 11 tions sending entertainment, news, and Lo^siana *?! .!!!!!!!.!!!!!!!!!!!!!!!!!! 10 information; Ohio is second with 34; Wisconsin".!!'.'.!!!!'.!!!!!!!!!!!!'.!!!!! 10 and New York third, having 28 sta- Florida 9 tions. Wyoming brings up the rear, J?iVr,jct o£ Columbia 8 without a single station. Every other Georgia"!. !!!!:;:!:;!:!:;;:!!;!!!:; "' 7 State of the Union has one or more Arkansas !!!!!!!!!!!!!!!!!!!!!!!!!!!!! 6 transmitting stations carrying enter- Colorado 6 tainment in some form. Arizona 5 Connecticut 5 Class B Application. Idaho 5 Several applications from larger WwtVVrghila '!!!:::!!!!!!!! '!!!!'''' 5 broadcasting stations for the class-B Alabama 4 license, permitting the use of the 400- Maine 4 meter wave, have been received by the Htah. • \ Department of Commerce, but to date Montana .'.'.'.' 4 only two have been authorized to trans- Maryland !!!!!!!!!!!.!!!!!!!!!.'!!'.!!!! 3 mit on this wave. They are the "St. North Carolina 3 Louis Post Dispatch" and the West- |outh Dakota 3 inghouse Station, Chicago. The offi- Nevada!!.""". 2 cials in charge of the licensing of radio New Mexico !!!..!!!!!!!!!!!!!!!!!!!!! 2 stations do not anticipate that more North Dakota !!!!!!!!!!!.!!! 2 than a dozen applications for the class- ?ort? J?ico,. 2 B license will be received, as only the Hawaii 2 most powerful stations carrying high- Vermont .!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 2 class entertainment regularly may hope Virginia !!..!!.!!!!!!! 2 to qualify. ~ ' Delaware 1 Foot New Ucmvm M.ssissippi 1 t>, . ,. , , ,. New Hampshire 1 During the past week, four licenses Wyoming 0 were issued for regular 360 meter broadcasting stations, as follows: Total 510 Volume 1 of RADIO WORLD Now Complete Oar supply of beck numbers of RADIO WORLD (Nos. 1 to 26) is kmited. We will take orders for the first volume until the supply Is ex- liausted. If you want these numbers, or want your subscription to start with any special number, let us know. RADIO WORLD CO., 1493 Broadway, New York City Magnavox. «J ^rinas <fy Entertainment C . a J „ rv .and Educaiio n 2=^= lolhe ■^floit) Science has bridged with wireless the m i les between city and country V TOW to the health 1 i and independ- ence of farm life, you can add the large city's most envied ad- vantage— access to wholesome, inspir- ing entertainment. Within the past few months more than half a million radio receiving sets have been installed by amateurs, mostly to hear the d.ily programs of Concert and Dance Mu- sic. Vaudeville, Speeches, Sermons, etc., broadcasted from central stations in alt parts of the country. Without a Magnavox Radio no wireless receiv- ing set is complete. It makes it possible to hear all that is in the air as if it were being played by your phonograph. Any radio dealer will demonstrate for you, or Write to us for descriptive booklet and name of nearest dealer. The Magnavox Co. Oakland, California N.Y. Office: 370 SevemhAve. Peon. Terminal Bldg. Digitized by i_9%.adio brings it MAGNAVOX teUsjt^ Google

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20 RADIO WORLD Radio Patents John Hays Hammond, Jr's., New System for Transmitting Radio Waves No. 1,425 ^J. Patented August IS, IfH. Patentee, John Hays Hammond, Jr., Gloucester, Massachusetts. JOHN HAYS HAMMOND, JR., one of the most prolific inventors in the radio field, has added another patent to his long list. It is an improved system for transmitting electroradiant energy, par- ticularly where a control station, and one or more auxiliary control stations, is operated. In this new system means is provided for informing the operator at any one of the auxiliary stations as to the responsiveness of the central station. A particular embodiment of this in- vention comprises an antenna or open aerial' circuit, which includes an induc- tance and which is grounded through the of sound; for example, a telephone re- ceiver, which acoustically operates the apparatus under test, that is, the trans- mitter, or receiver, or component parts thereof. A source of energy is con- nected to the receiver and the alternat- ing-current' energy produced thereby in the apparatus under test is measured and compared with the results obtained when other apparatus is tested under like con- ditions. In this way it may be deter- mined if the element tested — transmitter, receiver, diaphragm, or granular carbon, measures up to the chosen standard of efficiency. It is well known that telephone cur- rents produced by speaking into a trans- mitter are very complex and may be con- sidered as made up of currents of vari- ous frequencies, extending over the acoustic range. It is desirable in testing telephone devices to duplicate actual Diagrammatic rapraantation of a tranamiaaion system constructed In accordance with Mr. Hammond's invention. inductance. The inductance forms the seondary of a transformer which includes a primary inductance which is in a cir- cuit controlled by a normally open switch and arranged to be energized by a high- frequency electric alternator. A vari- able condenser is connected in a well- known manner to form with the primary inductance, a closed oscillatory circuit, which is preferably tuned to the natural frequency of oscillation of the open aerial circuit. The normally open switch is arranged to be controlled by an electromagnet, one end of the winding of which is con- nected by a conductor to a fixed terminal. The other end of the winding of the mag- net is connected by a conductor to one pole of a battery the other pole of which is connected by conductor to a switch which is arranged to swing into and out of engagement with the fixed terminal, and which is normally held open by a spring. For controlling the normally open switch either from a central station or from anyone of a plurality of auxiliary stations, an electromagnet is suitably arranged. * » * For Testing Transmitters or Receivers No. M2S.M7. Patented, August 22, 1*22. Pat- entees: Harold D. Arnold and John P. Mmton, East Orange, New Jersey. THIS invention relates to a method of and system for testing the compara- tive efficiency of telephone transmitters or receivers, and for testing the com- ponent parts thereof, such as their dia- phragms and also the granular carbon employed in the transmitter. The invention makes use of a source jf/ ' ft r make the coupling between the tuned search-coil circuit and the aerial circuits as tight as possible. This condition is desirable firstly in order to minimize the loss in signal strength due to the method of tuning; and, secondly, to increase the ratio of signal strength to stray effects which tend to distort the ideal polar diagram of the system. A radiogoniometer usually consists of windings disposed on two co-axial cylin- ders, the inner cylinder carrying the search coil winding and being capable of rotation. In order to make the coupling between field and search-coil windings as large as possible, it is necessary to make the cylinder carrying the search coil of as large a diameter as possible in order to bring the windings close to- gether. The magnetic field inside the outer winding is, however, not uniform but is more intense in the neighborhood of the conductors themselves. Conse- quently, as the search coil is rotated, the Figure 1 shows a perspective view with parts broken away, of the variable inductance; figure 2 shows, diagrammatically, a testing system that may be used; figure 3 indicates diagrammatically a wave filter; and figure 4 is a plan view of a coil supporting plate forming a part of the inductance shown in figure 1. working conditions as nearly as possible, while obviating the necessity of actually employing currents produced by the voice. To this end the invention pro- vides a special form of generator for energizing the receiver which actuates the element under test. This generator supplies current which continuously and cyclically varies in frequency over the important part of the voice frequency range, thereby testing the apparatus at all those frequencies which are most im- portant in speech. * * » To Aid Direction Finding No. 1,425,117. Patented, August 27, 1*22. Patentee: George Maurice Wright, Lyngrove, Chesterfield, England. IN the "aperiodic aerial" system of di- rection finding, using two fixed aerials, and a radiogoniometer, it is necessary to A radiogoniometer comprising two stationary coils in planes at substantially right nnglss. and a rota table search-coil comprising two windings In planes at an acute angle with each other. law of coupling between it and each field winding does not follow the sine law re- quired theoretically and errors are pro- duced. In the positions of symmetry, i. e. when the plane of the search coil either coin- cides with that of either aerial coil or lies midway between the two, no error will exist. Consequently the error curve takes the form of a cyclic variation making four complete cycles per revolu- tion of the search coil and if one aerial coil is parallel to the 0-180 degree line of the scale pointer system, then the points of zero error will be 0, 45, 90, 135, etc., and the points of maximum error about 22J/$, 67y2, etc. According to my invention I construct a radiogoniometer having a double search coil with its two windings in planes making an angle of substantially 45 degrees. The coils may be connected in series. In this case the total E. M. F. induced in the winding by the currents in the two aerials is given by the algebraic sum of the E. M. F.'s in the individual coils. And though the difference of each E. M. F. from the ideal case may be quite con- siderable, yet since the differences are of opposite sign they cancel out and the radiogoniometer will read correctly in all positions of the search coil. 52 Weeks for M.M Complete) Year File of RADIO WORLD Copies of Radio World No. 1 If you did not get a copy of Radio World No. 1, send us $6.00 and we will •end you this paper for one year, and start it with our first issue, which wifl b« mailed yon at soon as possible after re- maned yon at toon as posi ceipt ofordeToOgre

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RADIO WORLD 21 The "COPPER GIANT" "B" Battery ■ • GUARANTEED FOR TWO YEARS la ANT reeelrlnif art. beetiw It dm not deterio- rate while standing Idle. Tola U a T«rr targe better; deaUned for atatlonary or semi-portable taste tlaUono where abaolule reliability or or • per- iod of 7ear> U the Brit conel deration. Standard roltaaee — U, SO and 100. Any joltase made to order. Write for lltuatratlons. J. A. RITTER, Lartsdown-. Pa. BUILD YOUR OWN CoaipUU §Or. Instruction book lor tO*.an|T on radio rrr. ptlon and bow to m»km vlffhl rlaaart of f r*«taJ and larnva tab*- f\ f\ rwliliif a*>U. Wonderful lnforio III Irt • lion makes i mi uadvrttAYud radio. Al II . WW* f-n ordar w* aeiid bw ««i t-UU prlea liat of parta prepared eapeelaJlr (»r lb* eererai eeta deerrlbed. Ho* dlreet from taster, aad aa«e man. dallara. Retb etraetloa, book and price lUt piIm rtrtlpl of tO*. only. Meoe.r hark If not pleaaed. RADIO PARTS MFG. CO. Otpt. 18, P»rk p|. W„ DttrWt Ml*. MILLBRO RADIO SUPPLY 1S7 8even.Ii Avenue New York City NOVO B BATTERIES Medium Variablr, S1.00; Large Variable. •I.M. Ezlde Storage Batteries, 80 am- pere boars. $19.75. Fell Line of Radio Parti at Extremely Low Priest NOVO BATTERIES FOR RADI DEPENDAB GUAR ANTE] ASK YOUR DEALE i i i ■ ■ i NOVO MANLFACTllRINi ; 424-438 W n t?. yy > 531 SO DEARBORN ST.. CHICAGO. The Advice of An Expert AUTHORIZED STORE J THIS sign on the clean plate- glass window of a radio shop means that a competent radio expert is in charge within, who will gladly give you the benefit of his broad experience in selecting just the radio equipment to suit your purse and purpose. "It Pay* to Buy at the Sortinc Stor*" Mr. Dealer: — If you are a progreulTe nvrrlnnr. you may Let ua tell you how. Owner. Radio Scrrlce. Inc. New Tort Distributor* Eight Radio Stations for Also, Five New Radio Beacons for Lighthouses Attest Gov- ernment's Liberality EIGHT new radio stations have been opened in Alaska and five new radio beacon-stations have been added to light- houses. The opening of the Alaska stations means the introduction of radio broad- casting in Uncle Sam's northern terri- tory on a large scale. The geog- raphy and limited population of the territory make the general use of radio receiving sets somewhat diffi- cult of achievement, but government officials suggest that the stations may be used in connection with community radio- sets installed in town halls or mining camp central buildings for the enjoy- ment of inhabitants in these various lo- calities. The stations have been opened at Alitak, Akutan, Libbyville, Funter, Naknek, Chisik Island, Snag Point and Koggiung. _ The installation of radio beacon sta- tions in lighthouses is another step for- ward in installing radiophones in isolated spots. The new installations are pri- marily for code signals, but can be adapted to radiophone receiving-sets. The new installations are being made at Boston, Nantucket, Cape Charles, Colum- bia River, and Puget Sound. If financial appropriations permit simi- lar equipment will be installed at Dela- ware Bay Lighthouse, Los Angeles, and Blunts Reef. These are in addition to the two new radio beacons at Diamond Shoal. Cape Hatteras, and the San Fran- cisco Light Vessel. Three radio beacons have been in operation in New York har- bor for over a year: Ambrose, Fire Island and Sea Girt. Army Air Service Broad- casts TWO station, of the United States Army Air Service have made decided hits with the radio fans by broadcasting on a small scale — "entering the newest field of indoor sports," they term this public service. The 91st Observation Squadron, sta- tioned at Eugene, Oregon, on Forest Fire Patrol duty, is using the radio station at its flying field during spare time to entertain neighbors within a good radius and has met with marked success. There is no other station of any size in that locality broadcasting, so they are put- ting on a program chiefly of phonograph music and short talks on forest fire fight- ing and prevention, with occasional en- tertainment of other kinds. It is their intention to build a regular broadcasting room in order that they can carry music by a local orchestra. Great enthusiasm is said to be shown by local fans who listen in at home or attend the loud- speaker concerts held in the city park on special nights. Brooks Field, at San Antonio. Texas, also has an "amateur" broadcasting sta- tion where the officers and men of the aerial squadrons put on a varied musical program, his created considerable in- terest in the surrounding territory, ac- cording to letters received by Lieutenant McGregor, of the Field Communication Department. The post jazz band, aug- mented hy piano, saxaphone and cornet solos, furnishes the latest music nightly. The slopan, "Own your own radiophone." has come to be very common there- abouts. Subscribe for RADIO WORLD. $6.00 a year, $3.00 six months, $1.50 three "RADIO" VARIABLE CONDENSERS These condensers are the Standard of Quality. Carefully tested, inspected, balanced and adjusted to give maximum satisfaction. 3 plate Vernier fl.50 23 plate 43 plate Sent prepaid on receipt of price. Special discounts to Radio Clubs. Jobbers and Dealers write or wire for the biggest prop- sition in Radio— TODAY ! FREDERICK H. PRUDEN INCORPORATED LERNER BUILDING 993 Bergen Ave. JERSEY CITY. N. J. Digttiz

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22 RADIO WORLD Advertising Kates, Display, $5.00 per inch, $150.00 per page Radio Merchandisin Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Is America on Threshold of New Inflation? THE expansion of business in the United States since the first of the year has been so rapid as to raise the question as to Whether it was going too fast for the future good of the country— particularly as to whether the rest of the world was ready for sb much pros- perity in America, writes John Oakwood, in "Forbes Magazine." Since the first of the year there has been a marked increase of commercial and industrial activity in the United States, reflected in rising prices and ex- pansion in credit and Federal Reserve currency. This development of activity has been retarded by the coal and rail strikes. Accompanying the expansion in do- mestic business there has been an ex- pansion in the evident ability of the world to buy and sell from and to the United States, coupled with the ability to command a large volume of credit here; as to Europe in particular, there has also been a strengthening of her position to' do business" with the United States, and also to command a consid- erable volume of credit here. As to the future, there is good evidence that world conditions justify the expecta- tion of a rising volume of sound business activity and prosperity for the United States, but halting business in several of the nations of Europe and unsatisfactory credit conditions in them serve warning against any expectation of a boom. Therefore, business expansion in the United States, since the first of the year has perhaps been a bit too fast for the world, and the industrial and commercial slowing up caused by the strikes may not all be lost time. How Old Is News? A month or two after it happens — is that news? Think of putting away your Sunday newspaper and letting it age from four to six weeks before reading it. Radio is the most rapidly moving indus- try to-day. More new ideas, inventions — new patents — are coming to the front each week in radio than in any other field. Yet some people are still reading a monthly radio paper when they could read (and at less cost) RADIO WORLD, the national illustrated weekly, and get their radio news the week it happens instead of from four to six weeks afterwards. Some business men are still paying four times the cost of an advertisement in RADIO WORLD, the weekly, and inserting their advertising in monthly radio-publica- tions, jammed between a hundred or more pages of similar radio "ads." RADIO WORLD, published four or five times each month, is not as bulky as a monthly. Each advertisement is next to interesting text matter, so that it is seen, remembered, and brings results. Gentlemen, to-day it's the WEEKLY that pays advertisers best. RADIO WORLD is the Saturday Evening Post of radio. It's the best advertising buy in the radio field with its seventy thousand fan-readers, besides having more dealer-readers than any radio-dealer publication. Put RADIO WORLD on your advertising schedule. There is no duplicate circulation in this weekly — as it's the only national illustrated radio WEEKLY. Radio Goods that Stand the Test Manufacturer*, send a sample of without chars* WORLD, of your roods to our Technical Editor, Fred. Chariot Ehlsrt, MM N. Y. It will be carefully tooted and returned. If RADIO WORLD'S ondcraamoBt will be published in our mprchandt— or obligation of any Idnd on your part. Thla is a free terrice on the part of RADIO for no expense whatsoever on the part of the manufacturer, except the mailing of Vacuum-Tube Socket Manufactured by Teleradio Eng. Corp., 484 Broome Street, New York, N. Y. A VACUUM-TUBE socket of standard make. It takes very little room on the back of the panel board. The holder, which is made of polished aluminum, holds the standard tube manufactured by various concerns. The base, which is of a composition insulating ma- terial, holds four contact posts. Spring con- tacts are used to make direct connection with the prongs of the tube. ♦ * * Aerial Plug Manufactured by G. M. Jost, 1 Union Square, New York, N. Y. THIS is a plug of simple and rugged con- struction. It consists of a housing of In- sulating material, having a binding post on either side, with a condenser. The con- densers employed are particularly of good construction. The whole nnlt is so assembled as to make a rigid, compact, and efficient con- denser. The average capacities were approxi- mately .0003 mfd. When testing for receiving, the plug gave very good results whether the current waB turned on or off. At a distance of 40 miles from a broadcasting station uBlng a two-stage amplifier regenerative set, there- celver gave satisfactory results. The plug was not so efficient when the crystal receiver was used. A screw plug Is provided so that the unit may be connected to any lighting socket in the home. Radio Exports for July Total $385,861 RADIO-EQUIPMENT exports from the United States, during July, were valued at $385,861 and totaled 225,475 pounds in bulk. Most of the apparatus went to England, where $139,027 worth was forwarded. Cuba was second, im- porting $42,415 worth. New Firms and Corpora- tions (.The Arms and corporations mentioned in these columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Miracle Radio Co., 1312 Main St., Dallas, Tex. West Side Electric Protective Co., Manhat- tan, $6,000; J. Capohi, W. Q. Wheeler. (At- torney, B. F. Hamilton, 825 Eighth Ave., N. Y.) Glllen tc Timmlns, Lynbrook, electrical work, $5,000; P. and J. H. Glllen, L. J. Timmlns. (Attorney, D. Haar, 298 Broadway, N. Y.) Federal Radio Sales Co., 1011 Elm St., Dal- las Tex. Oak Cliff Radio Co., Tenth and Jefferson Sts.. Dallas, Tex. The Marconi International Code Co., New York City, has been dissolved. The Dubiller Condenser Co., New York, has changed its corporate name to William Dubil- ler Oo. New York Aerial Concert Corp., radio sales agents and distributors, $20,000. (Attorneys, Nugent & Nugent, 280 Madison Ave., N. Y., Muskegon Radio & Specialty Co., 419 Lake Shore Drive, Muskegon, Mich. Radio Equipment Agency, 1315 Main St., Dallas, Tex. Crown Radio Manufacturing Corpora- tion, Manhattan, $5,000; D. C. Josephson, A. S. Levy. (Attorney, M. Schwebel, 233 Broadway, N. Y.) Electric Co., Manhattan, $10,000; E. J. Bell, S. A. Spaldingr. J. V. Booth (Attor- ney, W. F. Tlmme, 350 Madison Ave., N. Y.) Coming Events The editors of RADIO WORLD will gladly publish news Items of all contemplated radio and expositions. Keep us posted by fuD ANNUAL SHOW OF THE ST. LOUIS RADIO ASSOCIATION, St. Louis, Mo., October 4 to 7, inclusive. CHICAGO RADIO SHOW, Coliseum, Chicago, 111., October 4 to 22. U. J. Hermann, managing director, 549 McCormlck Building. CINCINNATI RADIO- AND- ELECTRICAL Ex- position, Music Hall, Cincinnati, O., October 2 to 7, inclusive. TRI-STATE TOBACCO GROWERS' RADIO SHOW, Covington, Ohio, October 21 to 28, in- clusive. NEW YORK ELECTRICAL AND INDUS- TRIAL EXPOSITION, Grand Central Palace, New York City, October 7 to 14, inclusive. NEWARK'S SECOND ANNUAL RADIO SHOW, Robert Treat Hotel, Newark, N. J., October 4. 5, 6 and 7. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, inclusive, 1923, George A. King, director of publicity, 417 South Dearborn Street, Chicago, 111. PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION, Grand Cen- tral Palace, New York Citv, December 21 to 31, inclusive. Direction American Radio Exposition Company, 120 Broadway. BOSTON RADIO EXPOSITION, AND NEW ENGLAND AMATEUR CONVENTION, Me- chanics Building, Boston, October 30 to Novem- ber 4. inclusive. SPRINGFIELD RADIO EXPOSITION, Spring- field Auditorium, Springfield, Mass., October 3 to 7. inclusive. SOUTHERN CALIFORNIA RADIO SHOW. Combined exhibition of the Southern Cali- fornia Broadcasting Association, the Southern California Radio Association, and the South- ern California Radio Trade Association. Los Angeles. October 9 to 14 Inclusive. PHILADELPHIA RADIO SHOW, October 2 to 7. inclusive. INTERNATIONAL RADIO SHOW, Madison Square Garden, New York City, November 20 to S, inclusive. E. C Buchignani. director of pub- licity. Digitized by Google

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RADIO WORLD 23 Shall Foreign-Made Vacuum Tubes Be Admitted Free of Duty? THE report from Washington that Senator Joseph S. Fre- linghuysen, of New Jersey, has introduced an amendment to the McCumber-Fordney tariff bill, now before Congress, placing foreign- made vacuum tubes on the free list, created quite a stir in radio-manu- facturing circles in this country. Senator Frelinghuysen was prompt- ed, probably, by the report that re- ports made to him indicate that there appears to be an underproduc- tion of this important radio article in this country — a stand in which he is upheld by many dealers, as sev- eral of the appended letters will at- test. If there is to be an effort to corner tubes in America, there will be many who will not oppose Sena- tor Frelinghuysen's measure, par- ticularly as Great Britain announces that she has granted patents on a new tube which will equal anything manufactured elsewhere in the world. On the other hand, the proposed Frelinghuysen amendment is op- posed by many American manufac- turers and dealers who believe that the American article is so superior to any made in Europe, especially those manufactured in Germany and which, it is expected, will be ex- ported to this country in large quan- tities, that, should any underselling of the American product be per- mitted, radio, in general, would suffer. American tube manufacturers are endeavoring to put on the market only the best possible radio goods. They are endeavoring to produce apparatus that will give the radio enthusiast an outfit that cannot be criticized, so that when he purchases an entire set, or individual parts, he will realize that he is buying tested, standardized merchandise and that he can rely on it as if he were pur- chasing a phonograph or an auto- mobile. In view of the possibility of for- eign tubes being brought to this country free of duty and competing with the home -manufactured ar- ticle, Radio World sought the views of American dealers, whose letters are published herewith : Would Put Us Out of Business By J. E. Allison, Secretary, Moorhead Laboratories, San Francisco. RADIO vacuum-tubes should not be admitted to the United States duty free, for the reason that the production costs in Europe, to-day, are at a low cost — lower than ever before. Tubes can be manufactured there, shipped here, and distributed with profit, if admitted free of duty, at a price that would paralyze our domestic industry. Speaking for the Moorhead Labora- tories, its plant is equipped with special machinery, devised and built at a heavy cost for the production of vacuum-tubes only, and not suitable for the manufac- ture of other products. Admitting vacuum tubes to the United States duty free will simply put us out of business. A tariff, which would force the import- ed tube to a selling price equal to our own, is due to the men who have devoted much time and money to the evolution and manufacture of the radio tube. British Tubes Superior By M. F. Klicpera, President-Treas- urer, Klitzen Radio Mfg. Co., Racine, Wis. WE feel that vacuum tubes of a for- eign nature should be admitted into this country duty free. We understand that most of these tubes are manufactured in England and France, and to our knowl- edge we know nothing very definite about the German tubes. However, the British tubes have wov- en so superior and successful to the American made tubes and also of the extremely low prices at which they are sold, has led us to believe it to be very beneficial to radio trade if these tubes were admitted free. This admission would, no doubt, reflect very strongly on the present prices of vacuum tubes as manufactured in this country. We firmly believe the prices asked for tubes are beyond reason, and, therefore, a cheaper and better tube would be very heartily welcomed by the radio fraternity without question. * * * Foreign Tubes Should Be Admitted By Paul F. Johnson, Altadena Radio Laboratory, Pasadena, Col. WITH the tube situation as it is, we would be in favor of Senator Fre- linghuysen's amendment to the tariff bill to admit vacuum tubes free of duty. We do not know anything about tubes com- ing from Germany but from our knowl- edge of other things made in England, we believe that the English tubes are un- doubtedly good and would be glad to have a chance to try them out in this country. We believe that the Radio Corporation and General Electric Company are hold- ing up the public on vacuum tubes, sell- ing them at retail prices of $5 and $6.50 for tubes that probably do not cost them over 15 cents to make, and which they could sell wholesale at a price of 30 cents or 40 cents and make a big profit. Also, in spite of the fact that they have had all summer to caich up on their orders, we are still short of tubes out here on the Pacific Coast; and when the fall rush starts in, unless a big quantity of tubes ar- rives pretty quickly, there is going to be just as bad a shortage here as there was last spring. We have been trying all summer to get tubes that were ordered six to I eight months ago and have succeeded in getting only a very small quantity. If foreign tubes were admitted free of duty, we believe the General Electric Company would have to get a hump on themselves and also put the price down to a reasonable figure. * * * Would Benefit User By P. C. Leffel, Manager, Radio Equipment Company, Spring- field, Ohio WE would like to see the amendment to the tariff bill go through admit- ting free vacuum tubes, although import- ed from Germany. It would benefit the user as well as the dealer, from our stand- point of view. * * * Detrimental to Radio By J. C. Hobrecht, J. C. Hobrecht Co., Sacramento, Cat. T is the writer's opinion that this (ad- mitting vacuum tubes free of duty) would be absolutely detrimental to the de- velopment of radio in this country. The men who have worked to develop Amer- ican tubes and are putting them on the market are entitled to protection, and in a case of an emergency they are the only ones the country can depend upon. Con- sequently you can register my opinion as heartily opposed to admitting any tubes duty free. * * * There Will Never Be Another Tube Shortage By an American Tube Manufacturer. ASK the readers of Radio World to help support the radio industry of America by writing their particular Sena- tor that the tariff bill should levy a duty on all foreign made radio equipment. You can specifically call their attention to the proposed amendment which would mean that foreign made vacuum tubes would be admitted to the United _ States duty free. You can appeal to their fairness in supporting the radio industry of this' country. Another point is that purchasers of foreign made equipment will be at a de- cided disadvantage as regards service or spare parts. I grant that some products are entirely satisfactory when made in foreign countries, but anything as com- plicated as radio should be manufactured at home to give the best service from all standpoints. STANDARD HEADSET 2,600 OHM svrttvcsvur* $5.75 Dealert and jobberi write. Standard Electric Sales Co. 848 Broad Stmt Newark, N. 1. AGENTS Wanted fa every city and town to aaU radio apparatus. Good rommhwinm A few •tocldng agencies open to reliable parties. DBLANCKY, WELCH * COMPANY U Mfttiif Ste Pawtutthotf I Digitized by Google

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Ba a I Iwt Haka bl« mow Win anccaaain tola mi, OBerowded Bold. Trained men naadad. •1.800 TO S6.000 _ iraaaflyoan^.lwlirtraln^ankklx, vmjn jroor apar* time, to cooatroeUrntnH, oparau, ropalr. maintain and aoll radio out- Jala. Short oourao. low coat.aaaytarma, mono* goarantaa. Write for "Waata rata" FREE. Naval Transmitting Sets for Sale THREE hundred and ninety-six radio transmitting-sets are being offered for sale by the United States Navy Cen- tral Sales Office by sealed bids. These radio transmitting-sets are of short-range :*"*E Zttii'TZZZSK^aSZZuL type, C W-396, with vacuum tubes man- For CORRECT RADIO MAILING LISTS Urn THE POCKET LIST at ftadto " — »— ■ Moan ud Daalan U o» United Hateud Oaaada. baaad 1 • i,^.j"aLrs5s.. lto»te»«- "'jji^jyL/gag » 1 "**• '„ "SIT cLtUSwanrtaatar, 1M»» n.i.ii, nam far JantTltea Tn'i Sat ISth. Priaa SS.SS par aapj. ar I1S.M aar r»ar_(»»at la- Fn nipi/TMC i*n cajuungton street . Da PICIVEalNO, JANESVTLLE, WISCONSIN "TUNING IN" to no. uht tum^v^s*." ?J£W «»™«cnoM ««a "POST SOLDERING IRON (Tan Ira* wtta tka HaatJac Unit). Ramoraala Soloarim* TV POST ELECTRIC COMPANY St BAST «ND STREET, Dt». SM NEW YORE A TUNER THAT MEETS PRESENT STANDARDS The new ABC Tuner No. 5750, illustrated below, has been designed by Professor J. H. Morecroft of Columbia University to fit the A B C Radio Units System. Embodying the most recent developments, this tuner offers a service in the reception of broadcasted programs which sets a new standard of quality and economy. Writ* for latest catalogue of ABC Staadardiaod Radio UmrU aatd nam of limit Jewett Manafaduring Corp. 342 M*daaon Ave. (Dept. G.U), New York MIS MM ufactured by the Western Electric Com- pany for use on submarine-chasers dur- ing the World War. This apparatus is said to be reliable for radiotelephone communication within a distance of ten miles, but numerous instances have been noted where the sets have been used for distances up to JW miles at sea. In the hands of competent operators, under favorable weather con- ditions, they should have a reliable land range of SO miles. . Purchasers of sets have the right to operate them for any purpose, ««P* where a charge is made, under the De- partment of Commerce Regulations. A Unique Radio Experience EDITOR, Radio World: Recently there occurred in the little town of Fairdale, North Dakota, an incident which may be of interest to your readers ; and one, which, so far as I know, is unique. One day, when turning the tuning knob of a small set (tube detector with two-stage amplifier) the operator was surprised to hear telephone conversa- tion over a telephone wire that ran about ten feet below the aerial. Thoroughly surprised, he tore off his head piece and went to his own telephone where he called up the party he had heard and found that the words he heard had just been spoken. He had the tuning "somewhere in the shortest wave-lengths," when he heard the voices, but has been unable to duplicate the feat. Has anyone else had a similar experience ?— Albert Lundberg, Fairdale, North Dakota. Current Articles on Radio Listed RADIO enthusiasts who are anxious to keep in touch with current literature on radio developments and news will be able to do so by consulting the list of radio references prepared by the Bureau of Standards and issued monthly in the "Radio Service Bulletin" of the Depart- ment of Commerce, Washington, D. C The list is divided into the following topics : Radio Communication, Principles, Measurement and Standardization, Ap- paratus and Equipment, Communication Systems, Applications, Stations and Man- agement, Manufacturing, and kindred subjects. Fire-Prevention Data by Radio DURING Fire Prevention Week, Octo- ber 2-9, officials of the National Board of Fire Underwriters have re- quested broadcasting stations to cooper- ate in a campaign to stop fires and to generally educate the public in fire pre- vention. Several broadcasters have al- ready offered their aid. Data concern- ing fire fighting and fire prevention is being sent to the radio stations, for dis- tribution, by radio. Park Receiving Stations WIAY. WOODWARD & LATH- ROP'S a popular broadcasting sta- tion of Washington. D. C has expanded its service to the public by installing loud speakers in several of the Capital's parks. Hundreds of people assemble on Satur- day nights to listen to concerts.^ Enter- tainment by radio is thus furnished to many people who do not have receiving sets, and has the advantage of keeping them out in the air while the radio service is on. Latest broadcasting map 15c That is. a complete broadcasting map appeared in Radio World, No. 8. dated May » Mailed on receipt of 15c. Radio World Company, 1493 Broadway, N. Y. C Digitized by Goegfe-

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RADIO WORLD 25 AND VARIOCOUPLERS UNWIRED Hi" x «*'. _ 50 -Bakellte tube 4" i I" bannrare, S 1 .30 per set. include 10 mu per est for WIRE A RADIO COMPANY IMPORTED DETECTOR TUBE, $2.75 MeUiuf MtumV Guarantee 1000 Bumli Thii i* a real $5.00 value .•01 MM ::::::: £S Vario- Coupler $z.7S Tuning Coil* $1.75 Mail Orden Filled Pranally Send far Complete Lilt of Dpoclalo J. J. KELLEHER 14 UNION SQ. EAST NEW YORK CITY Pheee 8tuy. 8636 5 FEDERAL $ 53- W. 2200 OHM PHONES We an atawM oat our obx* end .III oejd oe. enywher, peetMld >r» rveol.t of five dollara. E lot. of too or more M.JO 0«». F. 0. B. Mr. York City. Send recelttaeee wit* ordor. Imaedl- oto thloweet. J. H. oft C. S. ODELL COMPANY Etteklloked ISJt 447-401 WEST 42ND STREET NEW YORK CITY THE GOODMAN PATENT PENDING The NlfrJeet Short Wave Tuner on the Market Only J6.00 * PP on 1 lb. for pamphlet. Order through your dealer. L. W. GOODMAN DREXEL HILL, PA. nrtoaoloro and .aria-coupler now go Into 1 irove Your Crystal Set Solid Gold Contact Cat Whlakere. Win Not Corrode, Ru»t or Oxidiie. Will laet a lifetime. Try one and aee how the Qual- ity ot your reception ia improved. rVice Special "EDMAR" Mounted Cryatala. H it ian't the beat you ever uaed, return it and we will refund the money. Price each T*« 4-Inch Fiber Solder- Web Diaka. Set of , three Aluminum Plate Variable Air Condomeera. Sold Knock- Down Only (Without Knob or Dial): 4J Plate CJS ZJ- Plate tlJS U-PUte Jl-Se 3-Plate (Vernier) He •row Dlraot Frew Ua. »eet PoetaaJd to Yoe. The Eddy-Marsh Company ■ Wo.tmln.tar St. PrwrlaWa, R. I. Foreign Inquiries for Radio Apparatus INQUIRIES are being received at the *■ offices of American Commercial Attache McQueen, Santiago, Chile, regarding the development of radio telephony in the United States. It seems probable that, before long, serious consideration will be .given to the exploitation in Chile of this new develop- ment. Legislation is now contemplated there based on the laws of the United States, and although it does not provide specifically for broadcasting stations by private enterprises it is possible that this service will be available through the leas- ing of government-owned stations during times of peace. If American manufacturers interested in the Chilean market will send catalogues and other descriptive literature to the office of the commercial attache at Santiago, the Department of Commerce states, this liter- ature will be placed at the disposal of all persons inquiring for this type of apparatus. Trade opportunities, during the past week, include inquiries from Czecho-Slovakia as to radio transmission stations. From the Philippine Islands comes a call for infor- mation on radio apparatus in general. American radio exports during July totaled 225,475 pounds of apparatus, valued at $385,861, which shows that some Ameri- can exporters are taking advantage of trade opportunities. Radio Thief Caught by Set in Motor-Car NE night last month, the home of Daniel F. Murphy, Cleveland, Ohio, was burglarized and a large part of the equipment of his radio station stolen. Among the loot was a high-powered sending set. Several days later radio operators in Cleveland heard a new station with powerful apparatus sending out mes- sages. The new station had no call number, was not licensed, and could not be located. Believing it was operated by the thief who robbed him. Murphy, an electrician, set out to find it. He installed a re- ceiving set on an automobile and night after night toured the city, tuning the set to the pitch of the unknown opera- tor. When the messages grew faint, he changed the direction of the car. Finally repeated circling of a particular block failed to show any point where the messages could be heard more plainly than at another. Eric Kutz, 18 years old, lived in this block. He had become the pride of the neighborhood with his new wireless set. Persons came to his home every day to see the set. As fellow radio fans, Mr. Murphy and his friends also visited the house. There they recognized the stolen apparatus. o Radio Courtesy WOR overstayed their time last Monday evening, thanking WJZ for the lat- tcr's courtesy in permitting them to encroach on five or ten minutes of the RCA's sched- ule. The thanks were sent over the air by WOR's fair announcer with an almost ironic politeness that called to mind the way Carpenticr and Dempsey shook hands be- fore the battle — 2 PI. in "The Globe." Another Epitaph Sad the tale of mild Ben Meyer, Who tried to fix a call-bell wire; Tapped high voltace to his sorrow ; They're grounding Hen. at ten tomorrow. — "Science and Invention." Fifty-two ieao.es for f6.00. Snb. De- partment, Radio World. 1493 Breomdway, N". Y. C. GOING— and Going Fast We haw. eaty a few Ml aad Mm are teams raat oet walla the* teat we will aoetleea la •oil tkew at the rodent erloe. VT 1 Detector and Amplifier 17 JO VT 2 Detector and Amplifier. . Ike above tube, aro the conoleo are aTa. raopeettfoly. "RADIO BUILDER" PLANS Br Man. la. LIBERTY RADIO CO. lee Liberty Street New York City "MIRAD" "Quality Radio I Plate Variable i Mirad Varicouplera US )*M Ohm Double Head ~ ISM Ohm Single Head (Money b Mired a Plal Mirad 43 Plate Variable I Mired Detector Unit MM Mir ad T.o-Step Amplifier SJt Poetaaw Paid Dealer.' Sample of Above 3% OS* Miracle Radio Mfg. Co. INTERURBAN BLDG-, DALLAS, TEXAS Welcome! Come in and hear the Coraco Radio Concert Daily, t A. M. to S P. M. nth noor. m w. died at. mm t> la tea lateat aad rroauwt Improvement la radta. It baa ee eould. MnrMetlona — oe IneialleUone eilionoa ta ae euapW to operate aa a prawn. I Que. If yea aaeawt aan. write far full Information. The Coraco Company, Inc. New York KNOCK ED- DOWN VARIABLE CONDENSER MONEY SAVING PRICES An ftoruratal? mad*, fell; raivkot etc out of enter m s :i±r%r. ! 4h«Mi hire boary aim doNuito -» : plosaa. All aUwvr i pla r*umloned ■ ■■■blld or I at the followteet lew prloaa aaaooablod by oorea. foDo atrerneeo fumlehed Hare order from oa "elder u] No of II PD eaaea I' la toe ilpaolur Mad I .00007 II 00023 II .0003 43 .001 pletea Cea- aoUj Ira »l oelag la- Lotf. Better Radio 473 ORANGE STREET Co. NEWARK. N. J. IGITHENS TRUTONE RADIO HORN— LOUD SPEAKER Firat ona> to eaJi on tan day trial Money back li vita TrstOD. ike beet, reer aaoaw wa| It la arid oe a ton da! trial ij 1 — ' EL IS ntitniis If am oarrvotj bj rw doaiar vrlia am. D%ttr\bntc* I and . ra.fj u»u#- AUTO PARTS MFG. CO. HIS Tromhly A«, Detroit, Mkh. Digitized by Google

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26 RADIO WORLD LIST: $27^0 Complete Assembly (Panel site: 7" x 18") Super-sharp tuning due to double tuned ready for soldering, circuit. All parts of highest quality. Of type that usually sells for double the price. Supplied in Assembly Form — panel drilled and engraved and fastened to handsome mahogany finished cabinet ; all parts packed in cabinet; all wires cut, bent and turned Complete, as illus- trated and described, with blue prints and instructions, at $27.50. Send check or money order for immediate shipment. DEALERS & DISTRIBUTORS: Write for attractive proposition on this sure-selling set, parts and books. RADIO COURSES, Inc. (Dept. 11), 552 Seventh Avenue, New York ALL MOULDED List, $6.00 All parts Moulded of High Dielectric Mate- rial. Accurate Tuning Assured. All Hardware Hig-hly Polished Nickel Positive Contact In Bear- ing Shafts. IN PACT THE BEST MADE F. R. S. RADIO CORP. Manufacturers W East Fort Street Detroit, Mich. ALL MOULDED List, $6.00 The Teleradio Tube Socket Whose handsome design is adapted for table or panel mounting. Of shell-drawn aluminum. All parts perfectly insulated — legs are not current-carrying. Terminals plainly marked. List Price, We 2,000 Ohms, $6.50 2,200 Ohms, $7 JO; 3,000 Ohms, $9.M Each Teleradio Supersensitive Headsets equal the performance of phones selling at $12.00 and $15.00. If your dealer has not stocked Teleradio Products writs us direct DEALERS and JOBBERS write for our PROPOSITION Variable Condensers, OTHER TrLERADIO PRODUCTS 3, 11, a and 43 Plates, list prices are Jl-Si, $UM, %SM and S4M, respectively. Filament Protectors, SSc Fixed Phone and Grid Condensers, SSc each. TELERADIO ENGINEERING CORPORATION BROOME STREET NEW YORK A Fitting Birthday Present for Those Interested in Radio Are you cudgeling your brain In an effort to think of an appropriate present for a relative or MondT If that relative or friend is interested in radio, WHY NOT SEND HIM OR HER RADIO WORLD FOR THE COMING twelve months? Send us M M for each subscription you want, and we will place the names on our subscription list for one year, postpaid, and we will also send special is, lis so the siMrassss you send us announcing that the subscriptions were sent with your compUmenta. Address Subscription Department, Radio World, 14*3 Broadway, New York City, N. Y. REPRESENTATIVES WANTED! RADIO WORLD wants young hustling subscription representatives in every college, school, factory and big business concern thruout the country. Send us your name and address for full particulars. RADIO WORLD, 1493 Broadway, New York Gty. Points to Remember When Buying Parts CO many thousands of small manufac- ~ turing firms sprang into being last winter when the radio excitement was at its height that all of us— fan, amateur and professional— are reaping the sad re- wards, says "The Globe," New York. But because of their inexperience the greatest loss falls on the radio fans, particularly those who are just becoming interested in the subject. To this latter class the following points will be of assistance in selecting sets and parts: Trade only at reputable stores. Buy only reputable goods, preferably those having the name of the maker on them. Insist on having every part tested be- fore leaving the store. In the case of tubes this means more than merely at- taching the proper prongs to a six-volt battery to see that the filament is intact It means that the tubes should be tried out in a set that is actually in operation. Arrange with the seller that any parts found unsatisfactory may be exchanged or the amount paid refunded. All stores with a solid backing will readily agree to this. Don't shop with a dollar in your hand. Watch the quality of the goods. Cheap goods give cheap results, first, last, al- ways. Pay a little more and get the tubes, phones, tuning units and other acces- sories that have made a name for them- selves. It is dangerous to pay too little for complete sets. Cheap transformers are useless. Poor design is fatal. Disorderly arrangement of parts is sure to prove disappointing. If you buy a complete set, buy one with a confidence that tells you that you will never have to open the cabinet unless you so desire. Buy a set that you can eventually ex- pand into your ideal outfit, whatever that may be. And lastly — when you shop— take some one along who knows the game from aerial to variometer. If you do that you can have no regrets. Ether Wave's Journey to Mars EDITOR, Radio World: I wish to call your attention to a slight discrep- ancy in an article entitled "Radio Travels to Mars," in the September 16th issue of Radio World. To quote from the ar- ticle: "Every ether wave that leaves the earth touches Mars a few months later." Radio waves travel at the rate of 186,000 miles per second. As there are 2,592,000 seconds in one month (30 days), if it took even that long for a wave to reach Mars, that planet would be placed at the tre- mendous distance of 482,112,000,000 miles from the earth. As a matter of fact Mars is, approximately, 44,000,000 milej away, and would be reached by a radio wave in a trifle over four minutes. A wave reaches the moon, which is 240,000 miles away, in about \% seconds. The wave reaches Neptune, the most distant of all the planets, in less than four hours. I noticed in the same issue of Radio World an article based upon the work of our own school on this station; and as we all like publicity, I was very much interested. — Henry Hall, Squadron III, Naval Air Station, Pensacola, Florida. A Radio Necessity! Latest broadcasting map 15c. That it, a complete broadcasting map appeared in Radio World, No. 8, dated May 20. Mailed on receipt of 15c Radio World Company, 1493 Broadway, N. Y. C.

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RADIO WORLD RADIO CITIZENS WE SAVE YOU MONEY Send us a list of your radio needs for our prices. // It's Radio, we have it and we sell it for less. JOHN R. KOCH COMPANY WEST VIRGINIA Radio dealer* since 1911 COMPLETE LOUD SPEAKER A QUALITY PRODUCT At the price of a high grade headset With a 8PIROLA CONCERT you can •ell your headaet — you won t need It even for tuning In the distant stations. SPIR- OI.A CONCERT Is so sensitive to weak signals that It Is even better for this purpose than the ordinary headset — and everybody can share the fun ot "picking up" new stations. We have picked up five hundred mile stations more than a thousand miles away In this manner, using two stages of audio amplification and the loud speaker alone. We have heard a thousand mile station twelve hun- dred and fifty miles away loud • n o u r h to hear clearly through sev- • r a I good sited room*. And at the same time 8P1R- OUl CON- CERT brings In the near- er • t atlons with all the loudness you could wish and a* clear and natural at life itself. Cabinet type with a special loud speak- ing unit built Into It as an Integral part — complete with cord, ready to hook In. In the same way as a headaet. No exciting battery or extras required. Beautiful ma- hogany or dark oak finish, browed throat, at dealers *-» O CJfl or prepaid direct Ql.ti.OV -If yeu wlih to return your SPIROLA hr lay rsasM vhatMenr ds M wlttlln ten day. ui ii im ii<nliM .— I tm tm^m 1U *m» !M Str~t I <n. innsh Oti* Over 50000 H0MCHARGERS in Us n Fin* Work VARIOMETERS tnal will give is City and set uarwbied wttb ear Vartaavsplsr. GUARANTEED TO DO OR MONEY We free. 0.1and, Inc. ^iTT^tl SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City. Please send me RADIO WORLD foe _ months, for which please find enclosed $ — ■OBSCRIPTION RATES: ling!* Copy I -U Throt Mootk. 1» SU Mootks 3 00 One Year (H Issues) 6.00 Add H.00 a Year lor Foreign — Digitized by '

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28 RADIO WORLD PATENT r ^520 FIFTH A.'. riki ADVICE RwnumM *r Dealers /tor KsUakmty R ADIO STORES CORP. VARIABLE CONDENSERS- PLUOS-KESISTANCE UNITB, ETC. ttt WW «*t* IMA Hot Ye* r— Rocky Mountain Crystals— ■ KTTIB THAN tALMA Msnufaetmrtrs. Jobssrt. Dealers. CMi, ™*P<» for Srwctal Traw Prfcw Itckt Mm*. Mb Pwfctb, Ik. » * OMUIOII «T, HBW YIIK, H. V RADIO INSULATION "SPAGHETTI**— VARNISHES— WAXES COMPOUNDS — TAPERS— ETC ESTABLISHED ISM Write for Prtos Bulletin and Sowielas. HITOH ILL- RAND MFQ. 00- 14 VMS* St.. H.Y. RADIO MAILING LISTS 91T0 Betall Badlo Dwlan. United State. per M. IT.50 1184 Badlo Manufacturer. par Hit. 10.00 1830 Badlo Supply Jobber. per U.t, 11.50 25 7 Radio manufacturers of com- plete Beta per Hat, 4.00 260 Badlo Station. par list. 4.00 14000 Badlo Amateur, and Man- ager, of Badlo Station.. ..per M. T.tO Neatly typewritten and ready to wnd you on receipt of remittance covering the amount TK.WlE CIHCI UR ADDRESSING CO. 166 W ADAMS STREET cmCAQO, ILL. SHELTONE LOUD SPEAKER No tubing or born to distort delicate note.. Swell* every sound into fuD richness! SHELTONE CO. 20 Clinton Street Newark, N. J. $COOat all good dealers OR DIRECT BY MAIL "Radio Supplies Variocouplers, Variometers, Headsets, Transformers, Sockets, Rheostats, Etc GS35SrI Crystal Set $^ Or Money Refunded PRICE, "X Send fifty cents for 20 efficient blue print hook-ups. Any Radio Set Made to Order or Repaired Sunbeam Electric Co. 71 THIRD AVE. NEW YORK Pictures and Facts About Armstrong Amplifier Radio World has published a number of pictures, diagrams and descriptive ar- ticles regarding the New Armstrong Sup- er-Regenerative Amplifier. The numbers containing this material are dated June 24, July 8, July 16, August 6 and Sep- tember 16. They will be sent postpaid on receipt of 16 cents each, the five cop- ies complete for 75 cents. Or you can subscribe, $6.00 yar; {3.00, six months, and have your <- * riptlon start with the number il.it- i RADIO WORLD CO., 14!.." " ••«• York. Important Change in Second District Radio Schedule ANEW schedule for broadcasters in the Second Radio District, New York, is now in effect. The new pro- gramme has been arranged to eliminate interference so far as is possible: The management of WJZ had the priv- ilege of broadcasting on 360 meters, shar- ing the time with the less powerful stations, or going in with the Class B, the most powerful stations in the Second District, and operating on 400 meters. The Class A stations agreed to stand by on special occasions should WJZ, the Radio Corporation-Westinghouse station at Newark, N. J., want to broadcast con- certs, such as the Stadium Concerts given by the Philharmonic Orchestra; play by play results of the World's Series, and the Saturday afternoon football, also, to permit WJZ to broadcast every evening. Class A stations are: WWZ, John Wanamaker, New York; WBS, D. W. May, Newark, N. J.; WHN, Ridgewood Times, Ridgewood, L. I.; WRW, Koenig Bros., Tarrytown, N. Y.; WBAN, Wire- less Telephone Company, Paterson, N. J.; W A AT, Jersey Review, Jersey City, N.J. ; WAAM, I. R. Nelson Company, New- ark; and WFAF, Shotton Electric Com- pany, Poughkeepsie, N. Y. WJZ will continue to operate on the 360 meter wave length. As usual, the bedtime stories will be broadcast every evening from 7 to 7:30 P. M. by WJZ. This station will then stand by for an hour on Monday, Thursday and Friday and Saturday evenings and for an hour and a half on Tuesday and Wednesday evenings for the other members of Class A stations. Class B stations of the Second Dis- trict, New York, are supposed to keep up a continuous daytime and evening programme on 400 meters. At present the programmes for Class B stations are not complete. Class B members are: WOR, Bamberger & Co., Newark, N. J.; WGY, General Electric Company, Schenectady, N. Y. ; WHAZ, Rensselaer Polytechnic School; WBAY, American Telephone and Telegraph Com- pany, New York. The proposed arrangement will pro- vide continuous entertainment on two separate and distinct wave lengths from 8 A. M. until 11 P. M.; and 400 meters, sometimes, until midnight. Radio Operator Lost! Will Radio Find Him? J RAY ATKINS, a radio operator, last • heard from a year and a half ago on board the steamer "Bellemina," on the New York-Argentine run, is sought by his mother, Mrs. J. R. Atkins, Box 253, Midlothian, Texas. In the hope that some of his brother operators may know where the missing young man is, or that he may be located by means of radio itself through broadcasting, the Depart- ment of commerce is asking that his story be carried in both the press and in the ether. Junius . Ray Atkins served as a ser- geant, first class, in Company A, 111th Field Signal Battalion of the 36th Divi- sion, during the World War. He re- turned to this country on June 4, 1919, and was discharged at Camp Mills. On July 14, 1919, he secured a first-grade radio operator's license, which expired in August, 1921, but was not renewed. Later, he was a ship wireless operator. He is twenty-three years old and a native of Midlothian, Texas, where his father is principal of the high school. Subscribe for Radio World, $6.00 a year, $3.00 six months, $1.50 three months. V-A-C-U-U-M-T-U-B-E-R-E-P-A-I-R-I-N-G A _ c Save on u Detectors M 1-50 Save T U B E R E P A I R I N G Anplifiers3 ^ £ a "steels twurstaa m.s^t"'sae»^ss'**S* BM, MFNW, A. r. MMni WmkWt Bssalrlac all dstsetsn and i BacUetroa UV-SM, UV-SS1, C-IM. O-I.l. U M T U SS.M. » repaired tabes. w» warrant, win at*, i th* essss sasshrts ssrJsfsrtsa test sea E R E P A I R I N V-A-C-U-U-M-T-U-B-E-R-E-P-A-I-R-I-N-G W* an s*w la a pod Men to Ely. nar- ante* tar praam daBforiaf wUfciasHsj. tery neait*. A re.aaa.el. trial win saa. trm ear rattabtllty. 'go H. Porell Co, Iao. far MMMVILLK, MASS. SPECIAL TO AMATEURS VartatBiaBlsrs'"l"l!!!.'!!ll"l!ll.'!l."!'.]^s! I Stater 1 Rotor (Set) .71 Vavrteaneter Brow Sot M Postpaid REISMAN "'^Ya^cST* ALADDIN ELECTRIC COMPANY. INC COMPLETE RADIO SETS WRITE FOR PRICES, n West Broadway New York Oty Superior Radio Products AD Farts, Basstvtag Sat* Onsslili sad la Units, ■—a I- Denwtpttsn sod Prta*. Praapt gsta- BMM to Mall Orders. Dtalsrs Writ* for Proposition RADIO OUTFITTING CORP. RADIO BOXES All reek sarstatry **rk ear asnlarty. Writs Mr SPECIAL PRICES JOE MIFSUD & CO. m Canal Street New York CM* •471 The Nelson Radio Parts Co. Manufacturer, and Distributor, of RADIO APPARATUS Write for Catalog. ACADEMY STREET, NEWARK. N. J. Tel. Market 4066 Law Storage Battery Constant voltage, large amperage. Will ma two men ths without recharging. Attractive Dealers' Discounts Writs for Details WILLIAM LAW COMPANY Aborn and Sabta Streets, Providence, R. L $4 CRYSTAL SET "THE LITTLE WONDER" SZ-St UNMOUNTED Wonder in name and a wonder in per- formance. Cannot be equalled for the price. Catches distinctly everything with- in 26 miles. Send for FREE catalog, describing our "Little Wonder" set and listing radio sup- plies. Radl-O-Plate Panels. All suns cut to order. HOLLOWAY ELECTRIC SUPPLY CO. at Third Avenue New York Oty Digitized by Google

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RADIO WORLD 29 DRIVE HO TACKS AND SAVE $35M fad ant enea utZ den 111.1* up. Ford a* M OeaMaaa tS.TI. An toodo be boot and raanuteed hen te enpir. Band I ti.it unse lasted* dearer; u rw door. AUTO B«Ulr>MI»)T 00.. 17 ANNOUNCEMENT Products will be ready for the trade about October 15th, 1922. Discounts very attractive to jobbers and dealers. Watch for our future advertisements. Radio Products Corp. of America New Tak LEE RADIO CORPN. Haddonfleld New Jaroay ANNOUNCES THEIR "B-F SET (PoMMt AppWsd For) NEEDS NO AERIAL PRICE, $35.00 Complete Except "A" Battery, IffS.OO Write for Prop— ttl— . "NOTICE" An error In price en our Radio Receiver Watch Fob .._ In Irene of Sept. 16th. We •hall refuel to each one who remitted, the difference. The price ehoald have Immediate Dehveriet at New Price. RADIO NOVELTY CO. BIG MOOSE, N. T. i to BMH7 a* togalr- asd that en etin duneult to nod anywhere, n Mm nrt fen at than tubee on tbo ner- kat, andiJter promt aupplr Is ertnujoted. a — em not be erallableu any price, ae the/ te be anda esuoatr*b> far tbo U. 1 nnx uo or BUFPuaB. ix) war pricbb ON STANDARD stBBCHANDTSA OBT ©OA PRICES BEFORE PLACING TOUB ORDERS Amalgamated Radio Supply Co. EXPORT AND IMPORT _ W-A WnUaai Street New York CUy DEALERS SUPPUEO Fifty-two issues for $6X». Sob. Do- anortaarat, Radio World, 1493 Broadway, RADIO WORLD TBLBFHONA. BRTAMT till PUBLISHED BTBRT WBDNB8DAT (Dotal 8ATDBDAT OF SAMB WBBX) rBOat PUBLICATION OPTICA, 1111 BROADWAY. NBW TORE, It T. BT HBMNBBST RADIO PDBU0AXIOMB ROLAND BURKS HBKNB88T, U. B. HBMf — - a. ROLAND BURKS BBNKaBST. Battel. 1411 Bteadnaj. Man Te*. 1491 ASSOCIATE ■DlTOKSi suBscairnoN katxsi nrtaon easte a ens. M M a jeer. tt-M i tt null i 11. M tar f Ada Sl.ll • roar mPOKTANT NOTICSl are la taken at patents. Priority of onJan. tbo fM| pctetod f ifwd Mtt aad «■ J ftnTaasaVeanMl b* tenants) atUP(>*)aWj tS) BP* - la ajada la la New Office Building to Be Wired for Radio FOR the first time in the history of Pacific- coast office-building; construction, a 15- story skyscraper in San Francisco, erected by a navigation company, will be wired throughout for radiophone installation, says "Popular Mechanics." Tenants wishing to put in a receiving set will only have to "plug in" to a wall socket, as for a desk lamp, to be connected with the antenna on the roof and receive broadcasting programs from sta- tions in San Francisco and vicinity. Not only will the new building be completely wired as a convenience to tenants who are radiophone enthusiasts, but the company in- tends to install a powerful sending and re- ceiving set with which it is expected it will be possible to give orders to the captains of the company's nine freight and passenger ships, which maintain a weekly service be- tween San Francisco and the Hawaiian Is- lands. British Radio Situation BRITISH manufacturers appear determ- ined to keep the products of Yankee manufacturers out of their country, says "The Mail," New York. No one will suf- fer thereby except the English public They will be denied reasonably priced apparatus that will perform more efficiently than the products of their own manufacturers. We have been manufacturing amateur apparatus for many years and the experience we have gained not only makes it possible to produce reliable apparatus at reasonable prices, but puts our production at a point where it will take foreign competitors many years to reach. England, however, is going to do much better than we have done on one thing. Their broadcasting will be done systematic- ally from the very start. Who wouldn't start systematically after having had the op- portunity of witnessing the terrible mess we have made of broadcasting? However, we can overlook our blunders, since they were characteristically Yankee. INTRODUCTORY SALE Just to Get Acquainted Call and Look Over Oar Most ComplaU Stock of Radio Equipment It WELL PAY- to BUY NOW W eaters Electric Kelloaa, extra fine. 1% on. Federal An th ••••■•••••......*•>.. LOUD Maaaavos AmpUtoaaa OOMTT-JBTB CBTSTAX Federal, tvaraateed S1AJ0 Aertophoae, pnaraateed 10*0 CBTBTAL SBTS WITHOUT FHOK Pollock-Oreea Che pin DCST-PBOOF CBTBTAL Guaranteed, with errata! FSACnCB SATO With lamp aad cablaet for battery. J oat kar aad buner on bene INSULATOR* Moulded type Ill ft. lenpths. t ohm. with moulded knob DIALS Pine moulded type for rheoetat. Lure moulded type Black metal, medium else JO LOO0B COUPUE31 AND TV It ABA Beat looae coupler la a Murdock ST AO Beat double elide tuner LBS DTJO-LATKBAL COILS DL» It, tt and 10 S0.00 DL 75. 100 and too •*• DL 150. too <sa DL mo }M DL 1500 IAS TaLMJt COIL MOCItTTMOS Complete, with leads StJM nioNOOBAra ATTACHxaarra Fits any phonograph and phone SATS LIGHTNING Inside. Brach type Outside, Brach type CONTACT POINTS I Best trade nickel, with brass nut. lOo. Beet (rede nickel, with braes ant. SOa. B BATTB Beat guaranteed. MM V. Larre elie. tlH V U tt volt SJ EXIDE STORAGE BATTERIES *5% Off List RADIO DISTRIBUTING i AUTO SUPPLY CO. 64 West 66th St, New York City Broadway or 7th Arenas Bi •Ah or Ma Arenas -L- Tnese Priced Do Not Include Digitized by Google

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT It A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS taaaatt h> M«M tar •voaybcdy whe wants quick tM— ei hi the radto Bold. Readers of RADIO WOULD will find that It pan to read tl hi RADIO WORLD am tha la, oapr repaired tar thia Tha rata tar this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. U tc par ward (saladaauaa of eooDt tar « seeseecerthre haaarthaaa. 11% tar U paaaacrtraa hajarthaat U ansa tha). Chaana will ba Beads la stsaiHn» > taa slave hafara pnalkHaa. RADIO WORLD CO, MM ireadway. N. Y. C (Phana, Bryaatt «7MJ HELP WANTED— MALE EARN $U» to US* Monthly, expenses paid, at Railway Traffic Inspector. Position guaranteed after J months' spare time study or money re- funded. Excellent opportunities. Write for Free Booklet G-151. Stand. Business Training Inst., Buffalo, N. Y. THE LOOP'S THE THING. The coming aerial, most simple and inexpensive of all when our blue prints and specifications of the two better types are followed. Sent postpaid for $1.00. No •tamps. HcGehee Development Co., Box 1337, El Paso Texas. CASH FOR OLD GOLD, Platinum, Silver. Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash sent, return maiL Goods returned in ten days if you're aot satisfied. OHIO SMELTING CO, 337 Hip- podrome Bldg., Cleveland, Ohio. FREE with each $15.00 Western Electric Head- set, one UV 200 Detector tube. We handle every- thing in Radio. NEWBURGH RADIO SHOP, 236 Broadway, Newburgh, New York. Are you familiar with all the radio symbols used in the various hook-ups published in Radio World? If not, secure a copy of Radio World No. 26, dated Sept. 23. In this issue was a com- plete table of all important symbols used in radio construction and testing. Send 15 cents for a copy, or $8.00 per year, and have subscription start with that issue. RADIO WORLD, 1493 Broadway, New York City, N. Y. HOOKUPS i Over 100 blueprints to select from at 10c each. Send dollar for trial order. Radio Supply Co., Box 192, Pueblo, Colo. PATENTS— Electrical cases a specialty. Pre- war charges. B. P. Fishburne, Registered Patent Lawyer, 386 McGill Bldg., Washington, D. C. Manufacturers of Rogers Radio Receivers and Rogers Receiving Radiometers. Rogers Radio Company, 5133 Woodworth Street, Pittsburgh, Pa. TO THE TRADE— Fixed Phone and Grid Con- densers. Write for price list and sample. SALKEY RADIO CO., 2378 Eighth Ave.,' New York City. Weakly paper wants circulation and subscrip- tion manager with ideas and experience. Ad- dress by letter, R. W., room 326, 1493 Broadway, New York City. MOULDED COMPOSITION binding posts, 8c. each; 90c. dozen. Fixed phone and grid con- densers, 15c. each. No stamps. F. A. Keeler, 912 Harrison Ave., Boston, Mass. te-V.T. HOOK-UPS. Largest collection of dia- grams for radio receiving circuits published. In- cludes latest in radio frequency and super-regen- eration. Loose-leaf form complete with binder. Prompt deliveries. Postpaid, one dollar. W. A. Dickson, 409 East Fort St., Detroit, Mich. FOR SALE— Regenerative sets with detector. Complete with tube and B Battery, $35.00. With one stage, $50.00, complete with tubes and bat- teries. Satisfaction guaranteed. Edward Bittner, Schuyler, Nebraska. Exchange Jolly In tare* ting Utters through our Club! Stamp appreciated. Broadway, New York City. Betty Lee, 42S4 UN RADIO FREQUENCY TRANSFORMERS - Hear distant stations. Designed to fit any stand- ard socket. Three sizes, 160-5U0M; 500-1000M; 1000-2000M. Complete set of parts and full direc- tions for assembling, postpaid, (1.00. 3 for $2.75: 6 for $5.00. Arkenberg Agency. 702M, World Bldg, New York City. DO YOU USE A CRYSTAL DETECTOR T ARE YOU MAKING A CRYSTAL RECEIVER T Increase the efficiency of your crystal detector 1 000 per cent by using a "PT" Ultra sensitive Contact. Of special gauge and alloy. Makes and holds a quick, ultra-sensitive, stable ad- justment. Using galena, you may pound panel or table without disturbing sensitivity in ellght- est. Proved practical on shipboard bv an old- time Marconi operator. Using a "PT*' Contact on galena, Arlington (NAA) was brought ht clear at 3,300 miles (below the Equator): and Arlington came in loud at 2,200 milea (off Dutch Guiana). In both inatanoaa, nearby ahlpa natjag vacuum tubea ware unable even to bear NAA. As to stability, Cape May (WCY) waa worked over 1,000 miles, aandmg right through crystal with I KW spark, without affecting detector's adjustment. Replace your old insensitive cm- stable contact with one which will hold ita ad- justment in addition to giving louder signal* and music Indispensable for pocket acta and crystal detector-bulb amplifier outfits. A novice can install. "PT" Ultra-Senaitive De- tector Contact, with instructions, twenty -five cents coin or M. O. "PT" CRYSTAL CONTACT CO., Box 1641, Boston 8, Massachusetts. Answers to Readers J> ECENTLY we installed a radio set about 20 feet from the power lines of a nearby railway. We hove a 4-wire in- verted L aerial. Each one of these wires is 50 feet long. We also tried an inside aerial, about 100 feet long, but are unable to stop the machine-gun effect coming from the power wires. Is any way by which this interference may be eliminated ? — John Hoff- man, Phoenix, Arizona. The best way to achieve your object is to place the aerial at right angles to the power lines of the railroad. If this means that you are compelled to place the aerial so that it becomes anti-directional with the broadcast- ing stations, then we suggest that you make a T-type aerial of your present system. A single-wire aerial would be far better than your 4-wire aerial. • » e / have a regenerative coil using a tickler. I do not experience any results. Please pub- lish a hook-up of the connections.— James Wildflower, Toledo, Ohio. Radiate Your Home AMATEURS "Ground Buy your part* eri buy. We m sell you at win i and sets where tile deal- are manufacturers and will prices. Our Lilt Prlee Federal Phones — 2200 18.00 $6.50 Turney Phone* — 3000 Ohms 6.50 4.95 Klosnsr Vernier Rheostat.. 1.50 1.15 Porcelain Rheostat 1.20 .65 Thordarson Transformer 4.50 3.85 Radio Frequency Transformer 3.00 2.25 Write for Free Catalogue No. 100, containing hundreds of bargains. Perfection Radio Corp of America 702 Broadway. N ew York asted by Jamas Wildflower, Toledo, Ohio, A diagram is herewith shown of the proper connections for a regenerative set em- ploying the tickler coil. » * * / have a short-wave regenerative set, in- cluding 2 variometers and 1 vario-coupler, using a radiotron U V 200 and U V 201 as an amplifier. I don't seem to hear any signals and believe something is wrong. Could you off cr me any such suggestions to remedy my trouble r— Arthur Olsen. Brooklyn. Assuming that all your corrections are correct, it would seem that the trouble lies in wrong polarity. Reverse your plate- B battery and see if any change develops. All you need to do is join the positive pole of the B battery to the plate of the tube. The negative terminal, of course, is joined back to the storage battery. If you do not get any results, simply reverse the negative of the B battery on the negative of the storage. Your trouble lies there. * * ♦ Regarding the Armstrong superregenera- tive amplifier, ore the honeycomb coils right for the millihenry choke coils and in what position should they be. Can duo-lateral coil, No. 400, be used for the coil LA. What is the constant for the phone fixed con- denser T— Morris Siegel, Mahopac, N. Y. You may use the 400 turn duo-lateral coils for the 10 millihenries high-frequency choke. The coil you mention may be used. The capacity of this condenser should be .0025 mfd. * ♦ * Should I use a soft tube or hard tube in the detector step of a two-stage ampli- fier T Where are stations WLAW and WE AM? — Michael Brody, Springfield, Mass. Use a soft tube for the detector and hard tubes for the amplifiers. WEAM is lo- cated in North Plainfield, N. J. WLAW is the new police broadcasting station, New York City. * * * My aerial is a single wire, 85 feet long, having 35-feet lead-in. Is a single wire, 150 feel long, better than a two-wire, 75- foot aerial. With my present aerial, sig- nals seem to come in loud from one di- rectum. Why is this?— Arthur Swenson, Brooklyn, N. Y. Would suggest that you erect the one- wire aerial. 150 feet long, in preference to the two-wire. The reason your signals come in loud from one direction proves that yon have a directional antenna. This is accom- plished by the end the lead-on is taken from. If you change your lead-in wire to the other end, then signals from that di- rection will come in loud. Digitized by Google

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F>HONOTACH L Makes Your Phonograph a ! Radio Loud Speaker Radio Loud Speaker r RADIO WORLD (Trade Mark} ^ Adjuit it in Patent applied /or A New and Better Loud Speaker mt a vsry low colt The PHONOTACH connect* the receiver! with the tone arm of your phonograph. Utilizes the scientifically designed tone of the talking machine to. secure and beauty of tone. Price only $2.00 reas f..,/.i|r At your dialer, or ' » wad. W. A. MILLS 100 Park Ave., New York, N. Y. The FAMOUS GREWOL FIXED DETECTOR The GREWOL PRICE $2.00 In using the GREWOL you don't have to find the spot. Think what this means! THIS DETECTOR IS ALWAYS SET AND READY completely protected from dust. Gives the beat results. If your dealer does not handle the Grewol send us $2.00 and we will mail one to you. WRITE FOR OUR TRADE PROPOSITION RANDEL WIRELESS CO. I Central Are. Newark, N. J. Volume I of Radio World Now Complete If you did not get copies of Radio World No. 1 to No. 26, send us $3.00. Or we will send you this paper for one year, ($6.00 (or 52 issues) and start it with our first issue, which will be mailed you as won as possible after receipt of order. Trying to "Raise" Us AT WGI last night the radio program began with a Sleepytime Story. Next was "Banking," by Frederick W. Sleeper, and then came "Making Use of Last Year's Clothing," by Miss Harriet E. Ainsworth. If the radio fans listening in on WGI had . a wakeful night after that, let them consult physicians, suggests the critical and observ- ing F. P. A., in "The World." New York. • * * _ A Southern contemporary says it would like to hear broadcast the news of the exe- cution of the "inventor of white socks." Perhaps he would be more satisfied if he saw the event. • * • The Houston "Post" has invented this joke : "Why was it that George Washington never told a lie, Pa?" Because he was never asked if he picked up a 1450-meter wave. • • * "If you would care to speak," the lat- ter goes on, "or broadcast some of your material through the air—" Enough. Here is some humorous material : I read this poem into the air And it was broadcast everywhere ; It didn't have much sense or wit, But the Westinghouse people wouldn't pay for it. * • * A Sunday-supplement scribe on "The World," New York, brought his editor the following: "Oh, mother, listen to the radio!" cried a small boy in the B. R. T. subway train. He had heard the voice from the elec- tric announcer at the end of the car. ♦ • » "The radio religious service will never be popular," the Washington "News" ob- serves, "because the women can't see each others' hats." * • • And now, I suppose, aviators and sub- marine commanders and radio fans will bawl each other out in the new realms. What will happen when the day comes that we all carry an instrument in our pockets by which we can read everybody's thoughts? "So that's what you're thinking, is it?" a stranger may say to you— and punch you in the eye — Bruno Lessing. * * * Farewell, Static! GOOD-BY, static, W. .peed you on your .raw. So long, static; W. would not bav. you stay. Th. summer, eonr, the autumn'a here; No more your noises, many, queer. Will break in on our evening cheer — So on your way; move fast, old deer. Good- by. static; You sure have had your fun. So long, static; Your dirty work you've done. You've spluttered, hissed, and filled our set With wild, unearthly sounds, and yet We'll miss you. Are we glad 7 Just tat Us say we are- you bet. YOU BET! — H. Buy Your Radio Receiving Set at Manufacturers' Cost Bur your Radio Suppliea at e large dis- count below the list or retail price. If a saving of J15.00 to DM eel a ceiving Set or If e savtmg of 8% to el* telegraph us KING RADIO MFG. COMPANY 511 Penn Art. Wllklnaborg, Pa. INSU-LITE PANELS Fibre Size .01 per sq. in. 3/1C Fibre Size .015 per aq. in. f ibre Size .02 per aq. in. DEALERS: Write lor cfiicovef* General Merchandise Co. 142 Market Str< Newark. N. J. ELIMINATE STORAGE BATTERY by nalng the BRU. No. 4 SOCKET The only Socket that takea the $1 Unconditional Guarantee. WD-U Tl ts.oe Bruno Radio Corporation 152 Weat Uth Street, New York K.W. Latest broadcasting map, 15c. That is JtADIO WORLD, No. 8, dated May 20 Ma.led on receipt of 15c. Radio World Lompany. 1493 Broadway, New York City Hard Rubber Composition PANE I Q Conform to Na-y Specifications I AllaUjk A H.gh Resistance Panel, Guaranteed Not to Warp, and Drilled Without a Burr. Highly Poli.hed— Edf es Ground to Siae. ■ 1... T_ 1/W V II *~ ~ , a an m au — ... Standard ataae, 7.10,1 Is, 7»U»J 1«. 7,24,3 u. IhUd ||, ^ 12,14*3 la. h mediate delivery. Order* for special sixes received In the moouna shinned t£ of the same day. Binding poets, dials, and knobs to match "* ' ■ ef Cotl*. Variometers, VarlocoupUra, Socket. „*) Largest Discounts. ' rat Write for Free Sample! ALLIED RADIO COMPANY, INC CAREFUL ATTENTION GIVEN TO ALL RADIO ENTHUSIASTS Dept. D, 44S SEVENTH AVENUE. NEW YORK CITY. Fttarey J7H ^Digitized by- V O

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RAD tO WORLD r ««,coN.. alii §9 ■ TESTED MtCA CONDENSER ... W IfM JH - , ■* Micon CAP. .008 m. r PATCNTS PCNOIHG . MfO BY Lchu. rncsfiMit co. ,-r— * HCW YORK CITY j I ' •' JLl' Tested Mica Condensers now considered the highest type fixed mica condenser manufactured Absolute noiselessness Clarity of tone Accuracy Constant fixed capacity "MICONS for Supreme Radio Attainment" She Pric jHjKS ftjs 3 Complete diagram of the Armstrong Super-Regenerative Circuit free with every purchase of MICONS. JM M2S J» MS .78 jM LSt All OtlH for the d«w Armstrong SvpV-iUff«n«rmtiT« Circuit. At your dealers — otherwise send purchase price and the desired MICONS wffl be de- livered without further charge. Ant en ell a Does away entirely with antenna and all outside wiring, lightning arresters, switches and all other inconveniences. ANTENELLA enables you to enjoy Radio pleasures in any room in your house. Place your receiving set anywhere and merely attach Antenella to any electric light socket. No current consumed. AT YOUR DEALERS $2.00 If he can't supply you send purchase price and you will be supplied promptly without further charge. CHAS. FRESHMAN COMPANY, Inc. 290 HUDSON STREET NEW YORK CITY -Digitized by Google

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►ctober 14 15c. a Copy J6.00aYcar ILLUSTRATED T UBLISHET) EVER)? SEVEfi VAVS Necessary Parts for a Short- Wave Receiver See page 13 for hook-up and description RADIO ha* been surrounded by so much mystery that thousands of enthusiasts have been misinformed. The in- formation gathered has led many to expect results from their receiving sets which should not have been anticipated. For this reason, the half-tones herewith presented show the neces- aatry instruments the average amateur will need in making up a\ short-wave receiver. If assembled correctly this receiver should pick up broadcast matter over a considerable distance. It as the part of a set which makes up the Armstrong regenera- tive circuit. The upper half-tone shows a back and rear view of the parts needed, such as the two variometers and the tapped ▼a\ rio -coupler. The half-tone to the right is that of the vario- coupler, showing the method used in soldering the leads of the taps of the primary to the contact points, which are fast- ened to the outside panel. The regenerative receiver, using such ▼auriomaters, has come into common use in the reception of both radiophone and radio-telegraph communication, and the added increase in strength of signals makes it possible for this type receiver to catch very weak signals from exceedingly far distances. In other forms of receivers, amplifying tubes are required to increase the loudness of the signals. A common type of regenerative receiver with a complete diagram using these instruments is published on page 13 of this issue, together with an article entitled. "A Regenerative V.-T. Receiver for Short Waves." by Fred Chas. Ehlert. \G THE VARIO- COUPLER IN A SHORT -WAV) REGENERATIVE SET. Bv fiRORHF W MAV-see page 4

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RADIO WORLD PHONES FREE WITH EACH ORDER FOR ONE SYMPHONY CRYSTAL RECEIVING SET, AND ONE PAIR OF STANDARD PHONES ZSOO OHMS, AN EXTRA SET OF PHONES WILL BE GIVEN FREE TO THE FIRST 100 PERSONS SENDING THEIR ORDERS 'Retail Trice $5.75 THE REGULAR PRICE OF THIS OUTFIT IS: Receiving Set $1JL25 Standard 2500 Phone*. . . 5.75 Total $18.00 One Set Phones Free. . . 5.75 $23.75 Special Offer .$13.75 Save $10.00 Retail Trice $12.25 YOU SAVE $1040 BY RECEIVING ONE SET OF PHONES FREE, ALL GUARANTEED. SEND ONE DOLLAR WITH ORDER, BALANCE WHEN POSTMAN DELIVERS AT YOUR DOOR. STANDARD ELECTRIC SALES COMPANY 843 BROAD STREET, NEWARK, N. J. MICROSTAT VERNIER RHEOSTAT The most sensitive filament control and quickest, easiest tuned. This microstat has ten times the possi- bility of exact filament adjustment as over the ordi- nary wire rheostat. It eliminates grating and interfering noises, has lie knob adjustment and is far more durable being made of better material with greater care. This microstat takes up less room on the radio hoard, is neat and compact. The exact calibrations of the microstat are due to the gradual entering of two points into the resistance material of our own com- position which gives us exacting and most minute measurement of current to the filament as the oper- ator brings the two points together or separates them through the screw handle. Order through your dealer or delivered to any part of U. S. $1.40 MICROSTAT COMPANY WILLIAMSPORT, PA. Dealers, write for quantity prices III «Mt. ( tW tl.M NA-ALD GENUINE CONDENUTE DIAL The dial that runt try*. T^LW Numerela mm m bml sad kmb eo shaped that tun do met bide Urn. 1Mb eds* «Uk tfmi irutaaaoB to onto aewnue tMdtaciiav. Os»- wM Mt m> In aetal wit Win set num er dep. Flnlita end «nuMl petsnneat. _ ham prlM with Ihti quail t7 poauble eelr swears euaodtr predueUao. Special dealer and jobber proportion. An opportunity. A LD EN-NAPIER OO. a WIUow St. YOUR NEWSDEALER bom*. In order to be sure of f ottuur RA suggest that you either subscribe direct rfx montha, mod %IS9 three inearths. Or I Sw. — ■ 11 * saueL - - - - *■- 1 aalll SV wiU deliver RADIO WORLD to roar h mmt et not mlteiny a single issue, wo dealer at t*M a veer (S laeuee) *X**J si* montha, and US* thn to deliver RADIO WORLD regularly to your home each week i deUverir* of paper whenever requested. °- JJ- «J •■ RADIO WORLD regularly. — * or throngs, your - — instruct your I WW* „ Dealers will take standhi Radio World, lets Broadway, Now York. DEALERS have yon a stock on hand of die "SUNECO" ADAPTER if not write for proposition Fits In socket for use of AeiluUuu dry cell vacuum tuba. Insert tube in Adaptor Insert Adapter in socket Sun Equipment Company 67 Exchange Place New York City Digitized by Google-

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VOLUME TWO OF RADIO WORLD (Copyright, 1922, by Hennessy Radio Publications Corp., New York, N. Y. Entered aa second-class matter, March 28, 1922, at the Poat Office at New York, N. Y., nnder the act of March J, 1879] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. T« " VoL II, No. 3. Whole No. 29. October 14, 1922 = 15c per copy, $6.00 a year Radio Adds Interest to World's Series (C. Underwood & Underwood, N. Y.) people war* in touch with the World's Series, at the Polo Grounds, New York City, this year rrir before In the history of the great American baseball classic — the one sporting event dear to the heart of every citizen. And radio waa responsible, be- cauao, by radio, the newa of each play made waa Im- •t ail over the American continent sea. Evan in out-of - the-wa years, people had to await the lewzpaper, the news came through and earn play waa described almost aa quickly aa it was made. In the upper half-tone you will see George Kelly, first baseman of the Giants, tryin* out the transmitter by which the news was sent to WJZ. Newark, to be broadcast. The lower half-tone is a view of the radio section of the press box, the baseball expert writer, and radio operator A notable radio service waa conducted by RJce, baseball expert of "The Tribune." New Year*. Through his paper, the games were broadcast, aunst. It la reported, the news was picked up aa far north mm Quebec Though the weather was unusually warm for October, many feared that there would be an un- amount of static interference; but, from all re- lax* broadcasting came through unusually clear. WJZ has received many letters attesting this. It is at season the Polo Grounds will be (C Fotograms. N Y] Digitized by Google

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4 RADIO WORLD Using the Vario-coupler in a Short- Wave Regenerative Set By George JV. May, R. E. Primary of the Vario- Coupler. FOR receiving short-wave lengths up to 600 meters, the circuit employing the grid and plate variometers is the most popular. This circuit has been in use for a long time. Such a set will be found in nearly every amateur station. To the novice the different circuits used at present are more or less confusing, and it is hard to pick out the most satisfac- tory. For best results on most wave lengths, duo-lateral coils are hard to beat ; but the set described in this arti- cle is best for short-wave lengths. For broadcasting, as it is operated at present, this circuit cannot be sur- passed. The parts may be purchased or may be built at home. Two variometers will be needed, also a vario-coupler. As variometers are cheap enough to buy we will only describe the making of the coupler and the wiring of the set. The inductive tuner used in short- wave regenerative sets is sometimes called the vario-coupler. The distinc- tive features of the vario-coupler arc the use of the rotor for the secondary, which is placed in the field of the primary, and the use of the untapped secondary-winding. The rotor, which is frequently in the shape of a ball, is made to revolve through 90 degrees to change the coupling between the pri- mary and the secondary circuits. The primary of the vario-coupler is made of a tube, or cardboard, about 3yi inches long and about 4 inches high. It is then wound with about 64 turns of No. 22 double cotton- covered wire in one layer. The wind- ing is tapped every 10th turn starting from 1, 10, 20, 30, 40, 50, and then every 2 turns thereafter. This will give a tap for every 10 turns and every 2 turns. Thus there are 5 ten- turns and 7 unit turns. The tapping wants to be diagonal along the tube to prevent short circuiting. It will be easier to make the connections of the primary to the taps on the panel. A J4-inch hole is drilled about the sec- ondary shaft-bearing. It should be J^-inch from the top, in such manner that it will be concentric to the pri- mary and not rub against the sides. The secondary consists of a piece of tubing about inches long and of such diameter as to allow it to rotate freely within the primary tube. A piece of tubing about 2J4 inches long will do. It is wound with about 52 turns of No. 24 double cotton-covered wire in 2 equal sections separated by about '"eh. A J4-inch shaft is Secondary Terminal Secondary Schematic diagram of the tops of the primary of the Vario- Coupler, Ground and Aerial con- Secondary of the Vario-Coupler. fitted to the secondary tube and made fast with lock nuts. The shaft pro- jects through a hole and made to turn freely. Two flexible cords, or wires, are fastened to the secondary leads to provide for connection in the circuit. Enough slack must be allowed so the coil can rotate without injury of break- ing the windings or leads from the • econdary. j \ This vario-coupler may be mounted on a bakelite panel with knobs and taps for adjusting the instruments. The tapping process is very simple, as the wire is wound to keep track of the number of turns. Bring each 10th turn out and solder a wire from the tap to the contact point on the panel. This process must be carried out on all the taps, including the unit taps, care being taken to get the right taps on the right contact points. In wiring up the set, what is needed first is a piece of bakelite panel, two variometers, one grid leak and con- denser, one tube (detector), one B- ▼ Schematic diagram showing how the Vario-Coupler is used in a regenerative circuit employing two Variometers. This circuit is known as a regenerative and is used in short-wave reception. Drawn by S. N Digitized by Google

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5 First Alaska Broadcaster Is WLAY 13 Class A Stations and 11 of the New Class B Stations Makes Grand Total of 534 THIRTEEN regular broadcast- ing licenses, now known as Class "A," were issued by the Department of Commerce during the week which ended September 30. Among them is the license for the first broadcasting station in Alaska, WLAY. This is the station of the Northern Commercial Company, lo- cated at Fairbanks, nearly in the cen- ter of that territory. It will broadcast a program of entertainment for the benefit of those living within a radius of about 500 miles. The following are the Class A sta- tions in this issue: WLAV— Electric Shop, Inc., Pensa- cola, Fla. WNAF— Enid Radio Distributing Co., Enid, Okla. WOAA— Dr. Walter Hardy, Ard- more, Okla. WLAZ — Hutton & Jones Electric Co., Warren, Ohio. WOAE— Medland College, Fre- mont, Neb. WLAY — Northern Commercial Company of Alaska, Fairbanks, Alaska. WMAK — N o r t o n Laboratories, Lockport, N. Y. WNAD— Oklahoma Radio Eng. Co., Norman, Okla. {Continued from preceding page) battery (22 volts variable), one pair telephones, one storage battery*, aerial and ground. The accompanying dia- gram shows the internal wiring of the set and should be so wired. One vario- meter is placed in the grid circuit and die other in the plate circuit. Arrange the panel in such a way that the tube, socket, and rheostat are located in one end and the vario-coupler in the mid- dle, with the variometers, one on each side. Before attaching any of the wires, lay out the work carefully. Be particularly careful to keep all the wires as short as possible. Remember that every bit of wire added makes just so much more resistance to the set and will cut down the signal strength. The lead wires from the primary taps to the contact taps on the panel should be covered with "spaghetti." This prevents howling and squealing if amplifiers should be added to the set By doing this it will also lessen the danger of getting the B-battery through the filament by short circuit from some of these wires. By Carl H. Butman WNAB— Park City Daily News, Bowling Green, Ky. WMAL — Trenton Hardware Co., Trenton, N. J. WMAP— Utility Battery Service, Easton, Pa. WLAW— New York Police De- partment, New York City. WNAH— Wilkes Barre Radio Re- pair Shop, Wilkes Barre, Pa. During the week which ended Sep- tember 30, the Department of Com- merce licensed 11 broadcasting sta- tions in the new Class "B." This is the first issuance of the new licenses to the superbroadcasters, and cele- brates the licensing of the first broad- casters a year ago. All of the stations licensed under the new regulations are old ones which have been listed under limited commercial stations engaged in broadcasting for some time. They comprise large stations which have qualified with the rigid requirements of the department and are now en- titled to use the special 400-meter wave length assigned exclusively to these stations. Only high-class enter- tainment will be carried; mechanical music is forbidden. The stations which remains in Class A, over 500, are permitted to broadcast "canned" music if they desire. Among the B stations are the well- known calls of Westinghouse, General Electric, Western Electric, the A. T. & T. Company, and such papers as the "Detroit News," "St. Louis Post Dispatch" and "Dallas News." The first Class B list follows: WFAA — A. H. Belo & Co., "Dallas News," Dallas, Texas. WBAY — American Telephone & Telegraph Co., New York. WOR — Bamberger, L. & Co., New- ark, N. J. WWJ — Evening News Association, "Detroit News," Detroit, Mich. WGY — General Electric Co., Sche- nectady, N. Y. KSD— Pulitzer Publishing Co., St. Louis, Mo. WHAZ — Rensselaer Polytechnic Institute, Troy, N. Y. WOO— John Wanamaker, Phila- delphia, Pa. WEAF— Western Electric Co., York. KYW — Westinghouse Electric and Mfg. Co., Chicago. WCX— "Detroit Free Press," De- troit. Mich. The grand total is now 534.

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6 RADIO WORLD Neat Home-Made Tube Socket By Gordon S. Arthur Aasambly drawinc (full sin) emphaaUing th« mitnxi and compactnaaa of this socket. IT happens freqently that defects in tube sockets drive many ama- teurs to making their own. Sometimes porcelain sockets crack and break, while bakelite, or hard rubber, softens and gets out of shape when subjected to the heat of C-W transmission. The drawings accompanying this article show the detailed construction of a neat and compact tube-socket. It has been made and operated successfully. The dimensions given provide sufficient clearance between the binding posts and the socket to prevent short cir- cuits. Many amateurs may wish to enlarge the base so that there will be more room for making connec- tions. This, of course, is permis- sible since it does not effect the im- portant dimensions of fitting the tube base into the socket. The cylindrical tubing that forms the upright of the complete socket may be of brass, aluminum, or any other metal that may be available. A>V-L Hm.a»fc''Pwa- 3 Contact Snwwa 3 ML, Hbur — il 14 1 Seal* drawing* for making tub* sockat daacrlbad in tibia articla. It should be about 1/16 of an inch thick and 1 and 13/32 inside diame- ter. The contact fingers, of which 4 are required, must be of thin spring brass and cut accurately to dimensions. The base may be of hard wood, fiber, bakelite, hard rub- ber, or any other insulator. Make it about 1/8 inch thick. The position of the slot in the tube must be so effected that when the bulb is in place the 4 little projecting lugs on the base of the bulb make contact with the proper contact-spring. Radio Facts HE reason that dials cannot be cali- x brated on wave lengths is because dif- ferent users have to erect different types of aerials of different lengths, and all this af- fects the tuning of the receiver. Always remember that when there is more than one tuned circuit, each circuit must be equally tuned to secure resonance or equili- brium. Many who have receiving sets con- taining two or more circuits simply put a loading coil in the primary circuit and then wonder why they do not get results. A vacuum-tube receiver is not necessary to obtain the time service of Arlington. A crystal detector, especially a piece of galena, will pick the signals up several hun- dred miles distant from Washington. To understand die language of high- powered Hertzian waves it is necessary tor the operator to be familiar with the code. The radio alphabet can best be mastered by practicing on some instrument which wiD emit dots and dashes similar to those formed by the regular radio transmitter.

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RADIO WORLD Crystals May Yet Be Best for Receiving RADIO is now in a stage where owners of sets are not satisfied with some of the local broad- casting, but are diligently moving their dials and adding more equipment in hope of bringing in the so-called long- distance broadcasting stations. More often, the only portions that are heard are the call letters and the signing-off data. But what else goes with this tuning may be mentioned only by the owner himself, with its hissing, howl- ing, and rearrangement of batteries and connections. Radio this year is in the same con- dition as last, particularly in regard to creating long-distance reception of phone. Being a new instrument, we have realized its delights and enjoyed the entertainment it has produced ; and as soon as fans learn that the long- distance records are being accom- plished by most everyone, the idea will soon fall by the wayside. When this happens, the crystal-detector sets will either be used alone or in conjunction with the vacuum-tube amplifiers as a means of amplification. It may be said that a crystal is the only detect- ing device that will receive the phone without distortion during its action. Whatever the sounds may be, instru- mental or vocal, the crystal does not become paralyzed or get out of order. A good crystal-detector once set works alone, unaided by batteries. Crystal sets have a range from 25 to 30 miles to depend on. If the radio-broadcasting stations are to re- main where they are for some months to come, every receiving set will be of one of them. This Long-distance Regenerative Set Was Made for $27.80 Radio Knowledge Greater Than Instinct NO less an authority than Dr. C. P. Steinmetz, America's fore- most scientist, stated these facts re- cently in a public address, and gave it as his opinion that an antenna was a safeguard rather than a liability in case of electrical storms. Those of you who feel timid when storms are in the vicinity might well remember that Dr. Stemmetz' knowledge is more likely to be correct than your instinct. Even if these other stations are on exactly the same wave length as the one you are hearing, they will cause no signal at all to be received. You see, of course, that in localities where there are many stations, this ability to select to some extent the station you want to hear may be very useful. With the many typea of receiving seta precise directions regarding receiving Sets come under a general hand, so that broad instruction* certain to fit each individual case with duo allowance for the peculiarities oi each particular sot. The use of the regenerative arrangement complicate* the operation of a sot tent a lit tie ; but It also makes for louder signals that could not bo obtained with a simple circuit. Regen- eration la obtained by either the tickler coil or by a (rid and plate variometer. Such a set is shown in the above half- tone*. The upper bail- tone is from a photograph of Mr. Lebowit. working on a sat that he constructed for only P7 ta. Ha is onnections on his amplifier section. Note in the center of the photograph Tbe halt tone at tbe bottom la the front of Digitized by G00gk

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8 RADIO WORLD Vessels Now Guided Through Fog by New System of Radiotelegraphy Fl(u>* 1-— When a ship is directly over th« radio-piloting cable, the wivm etrike both collector coil* with the same force and effect. The slanting line is the cable from Fort Lafayette to Ambrose Lightship. Drawn by S. Newman. FOR more than two years, the aids to navigation on the sur- face of the Ambrose Channel fairway, in the harbor of New York, have been supplemented by a radio- piloting cable. It is submerged and in construction is similar to trans- Atlantic cables, excepting that it is thinner and has only a moderate num- ber of strands. It follows the course of the ship channel for twenty miles, from Fort Lafayette at the Narrows to the outer buoy near Ambrose Light- ship; and this fact, together with its name, "radio-piloting cable," gives some indication of the purpose for which it was designed and laid. Having perfected a system of radio- compass stations whereby a ship -ap- proaching any port on the Atlantic or Pacific seaboard, in a fog, may safely pick up the light vessel, or buoy, at the harbor's entrance, the United States Navy Department turned its attention to continuing that service right up the bays and into the basins or docks. It was not enough that a ship should be guided to the outer entrance of the harbor. That ended her navigational difficulties, to be sure; but it did not get the vessel to a dock, where her passengers and valuable cargo might be discharged. It often happened that all the time saved in making the chan- nel entrance by means of the radio compass was lost in waiting for fog to • lift so that the ship might proceed up the harbor to the docks. Time is valu- able where steamships are concerned. Delay means not a few hundred dol- lars a day, but thousands of dollars an hour, according to the size of the ship and the demand for her services. Perhaps the success of the subma- rine-signalling devices now employed on all vessels suggested the use of a .submerged piloting-cable. By means By Ortherus Gordon of two microphones placed in a vessel's forward hold, below the waterline and on the outer shell of the ship on each side, the navigator in the chartroom with headphones on, can hear the dis- tinctive underwater signals of certain lighthouses, sometimes for as much as fifteen miles. Not only that, but by switching from one microphone to the other, he could determine the direction from which the sound waves were coming and steer his ship accordingly. This is the successful principle of submarine, or submerged, signaling. A device placed at strategic points for transmitting sound waves, and the ship has "ears" to catch them. Why not an electrified cable along the channel course, with suitable ears on the ship for detecting the impulses sent out by that cable? The suggestion was seized upon and carried out. Experimenting took place at New London, Connecticut, and the project declared practicable. At once the Navy Department proceeded to larger experimentation in New York Harbor. The cable was laid and the tug, "Algorma," fitted with "collectot coils" which were to serve as "ears." The inner end of the cable was brought into Fort Lafayette and attached to the apparatus for producing the buzzer impulses sent out on this new form of transmitter. A flow of three amperes was found ample for practical purposes. On board the ship, the collector coils were placed on each side of the vessel at an equal distance from the 'midship lines. They consisted of from 400 to 800 turns of insulated wire, it having been demonstrated in the preliminary tests that the number of turns directly affected the audibility of the signals re- ceived. There must be a rigid same- ness about the coils, and all wires lead- ing to and from them must be iden- tically placed in relation to the central position of the headphones. In other words, the effective electrical constant must be the same. On this depends the accuracy with which the path of the submerged cable may be followed, since the guiding instinct is derived from comparing the strength of the signals as caught by the extended ears. If a tuner is used; that is, if the collector coils are employed as anten- nas and supplemented by a resonance receiving-circuit, the efficiency of the outfit is increased a thousandfold. For such work as this system will be called" upon to perform for the present, tuned circuits, while desirable, are not neces- sary. Figure 2.— When a ship is out of the channel and off her course, the collector coils on the side furthest from the cable receive little or no excitement; while the other one gets an overdose. The difference In intensity warn* the helmsman, who brings the ship hack on her course. The slanting line ia the cable from Fort Lafayette to Ambrose Chan- nel Lightship. Drawn by S. Newman, The ears may be placed above or un- der water — no difference is noted in the result. It is probable that they will eventually take their place in the bows of the vessel, alongside the micro- phones of the submarine bell and whis- tling device. In that position they will reduce to a minimum the distortion due to the shielding effect of the ship's hull. In the pilot house, the radio helms- man stands at the wheel, headphones on his ears. The left ear-piece is con- nected with the coil and circuit on the port side of the vessel ; the right is con- nected with that of the starboard side. The man who actually steers the vessel may be an "old salt" unacquainted with the mysteries of wireless, or a high- strung radio engineer with little or no knowledge of ships. If he can hear, and has intelligence enough to distin- guish between varying sound intensi- ties, then he can guide a vessel along the path of the radio cable without training or experience. All he must do is to keep the "hum" in his left ear equal to that in his right. He might be blinded, and the bridge blanked off by canvas screens, yet the ship would faithfully make her way through the fog which hangs between her and a journey's end. To one familiar with the elementary theories of radiotelegraphy, the prin- ciple upon which the success of the cable depends is readily understand- able. The Hertzian waves emanate from the cable in concentric circles, growing larger and larger as they move away from it. A ship directly over the cable, as in Figure 1, cuts these waves into exact halves, so that the "collector coils" on either side of Digitized by Google

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RADIO WORLD 9 What Makes the Radio Receiver Work By Donald Van JVyck WIRELESS receivers are made in various forms and desig- nated as single, bi-polar, and watch-case. In radio the watch- case receiver is used exclusively. Uusually two of these receiv- ers are placed on a head band and made to fit the head. The complete article is termed a head set. As these head phones, or receivers, must re- spond to very weak signals they must be made with very light diaphragms and wound with copper wire. Now, if the cap of the receiver is unscrewed, a thin piece of metal, known as the diaphragm, will be noticed. It is held bv magnetism. This diaphragm may be taken off; but be careful not to bend it Under the metal diaphragm are usually two electromagnets, or pei- manent magnets, with steel cores. On these magnets are wound many turns of copper wire. Both ends of the mag- nets are termed "poles." One is the north pole; the other, the south pole. The names are used so any person may understand the direction in which the respective poles would be attracted if the magnet were free to swing like a magnetic compass. If a piece of iron is brought into proximity with these poles, it will be attracted. Whenever current passes through such a coil, it becomes a magnet and attracts pieces of iron. The fact that the magnetic pull is present only when the current is on makes the device a very useful one for changing electrical energy into mechanical energy. These coils are seen everywhere in electricity — in door bells, relays, alarms, and telegraph sounders used in telegraph offices. In the telephone receiver, these mag- nets are mounted, one each, on the ends of the permanent steel-magnets. With this arrangement, the magnetism from the permanent magnets is carried up through the iron in the coils so that (Continued from preceding page) the vessel receive signals of equal strength. This is the navigating posi- tion of the vessel, and the one contin- ually sought for as the ship veers from side to side. As this veering there is a noticeable increase in the strength of the signals in one ear-piece and a corresponding decrease in the other. A slight shift of the helm and the condition is cor- rected. Thus, in the thickest of har- bor fogs, or in heavy rain or in blind- ing snow, American ports will present a safe entrance to vessels equipped with "ears," the installation of which costs less than a thousand dollars. Diagram showing the watch-caw receiver. Thla type of receiver la need exclusively In radio. It la small, light and durable. the thin sheets of iron, or the dia- phragm, is attracted. When the feeble radio-currents arrive at the telephone receiver, all the energy is used in mag- nifying the attraction that the magnet exerts on the diaphragm. This dia- phragm is an exceedingly sensitive piece of telephone mechanism. It takes very little energy to move it. Telephone re- ceivers will not operate when alternat- ing current is used. The current mov- ing in one direction would neutralize the current moving in the opposite di- rection, and there would be no vibra- tion of the diaphragm. Therefore, the ether waves, or radio waves, which are alternating current must be changed by means of the crystal or vacuum tubes when used as detectors. Receivers look more or less alike to a beginner; but there is a vast differ- ence between them, especially on the inside. A receiver, to really work right, should be wound with copper wire; but the sole idea, or principle, of the receiver hinges on the fact that there must be many turns of wire very close to the iron core. Receivers are usually rated by their resistance; but this method is entirely wrong. The easiest way to rate receivers is by the resistance of the wire used ; but a great mistake is made when this is done, as this resistance is detrimental to the tel- ephones. • What is expected from a telephone receiver is the number of turns, or ampere turns, with the least amount of resistance. To get this re- sistance, a larger size of wire could be used ; but when this is done, it will be found that, owing to the thickness of the wire and the distance from the poles, the resistance will increase, thereby lowering the efficiency of the phones. But this is absolutely contrary to correct receiver design. As the re- ceiver has the resistance, it lacks the number of turns and, actually, less wire is used. This will give the re- ceiver less efficiency in its work, as the high resistance will deaden the signals. Each receiver will have a total re- sistance of 1,000 ohms. The two re- ceivers in series will have a combined resistance through which a current of 2,000 ohms must pass. It does not pay to go much higher than the 2200- ohm receiver. It is far better to secure the extra value in getting the very best mechanical design. As the wire used in receivers is very fine, great care must be exercised, when the receiver is open, not to touch and break these fine wires where they connect to the binding posts located inside the re- ceiver. Another thing in a receiver that may be greatly improved upon is the dia- phragm. It is evident that if the dia- phragm is to give out sound, it must be able to vibrate freely. Some of the trouble with receiver diaphragms is due to the fact that they have not suf- ficient clearance from the pole pieces, making them inoperative. When this is evident, tighten a little on the cap and notice the result. If no change is noticed, then remove the cap, reverse the diaphragm, and then rest the re- ceiver. If the diaphragm does not clear the pole pieces, a paper washer may be used. The washer is inserted between the base of the receiver and the dia- phragm. The iron diaphragm is held in position by means of the cover and the action of the poles. Should a current pass through the coils of the bobbins, the pull of the poles on the diaphragm will be varied. This variation causes the vibration of the diaphragm and, consequently, produces sound. This is satisfactory in most cases. Digitized by i most cases. Google

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10 RADIO WORLD Plate Voltage an Important Element of V-T Transmitters By John Kent ONE of the most essential parts of any radio transmitter is the correct high-plate voltage ap- plied to the plates of the vacuum tube. A very good plan to follow in the con- struction of any type set, is to design the apparatus so that it will work ef- ficiently with as few pieces of apparatus as possible; and yet, parts may be added from time to time that will im- prove the set in general and not put on the builder too great a financial stress. A simple vacuum-tube transmitter is no more complicated than the average re- generative receiver, which it resembles. A simple vacuum-tube transmitter making use of the standard parts and utilizing the B batteries for high-plate voltage may be as- sembled easily in any radio ama- teur's workshop. The parts needed for a small trans- mitter consist of an inductance — which is used as the inductance for the antenna as well as for the grid — plate coupling-coils of a vacuum tube and its controls ; a variable condenser ; a means of modulating the currents generated by the oscillator of a high voltage source for the plate circuit and a micro- phone. For the plate voltage, ordinary B batteries may be used. However, use batteries that have a variable voltage from 22 to 500 volts. This will enable the operator to cut in just the amount of power needed for the plates of the tubes. The ordinary flashlight cells will not work so well, because there will be quite a call on the battery and, of course, these batteries will not hold up and will have to be renewed frequently. If a transmitter tube is used, the plate voltage will have to be between 350 and 500 volts. Hundreds of ama- teurs who are now using a transmitter for C-W (continuous wave) work, em- ploy the Colpitts circuit in order to know what the plate voltage does. It may be repeated that a good battery for the plate voltage makes the set work in a satisfactory manner. Signals have been transmitted over some distances, and by using the regular transmit- ting tube the range is increased considerably. Regarding the aerial, the average radio fan will have to improve upon his aerial which is being used for broadcast receiving. It is quite im- possible to send out signals of a wave length, and keep within the law, on a single wire 100 feet long. The radio fan will have to build an antenna for his sending set which will give him a sending wave-length of 200 meters. Such an aerial may be constructed by building a four- wire inverted-L aerial, 50 feet high and about 100 feet long. Particular care should be taken in the erection of it. It should not be placed near metallic objects, and the best of in- sulation should be used. Satisfactory results will be secured only after careful adjustment of the various pieces of apparatus used. Do not be discouraged by the first results, which are often very poor. Further experimenting, the changing of a tube, renewing a battery, lighting the tube more brightly, will increase the radia- tion, and improve the experiment. A thorough understanding of the ap- paratus, and the workings of the cir- cuit, and patience, will work wonders. How to Use Your Bed Spring as an Aerial r *; LJ*_ mm (Dulh i i.. m.. C. Kauel &. lieruen. Revra Sonleot There is nothing complicated about radio re- ception. The apparatus may be of the simplest sort. If the distance to be spanned is relatively small, but little experience is necessary; for any- one may turn the knobs and adjust the detector. No license is required and anyone may intercept radio waves without formality of any kind. The coat is low, considering the wonderful itie> of a receiving- set. After all, it is a question of what is expected of the receiving equipment, and successful results demand that the receiving equipment be fitted to the require- ments of the owner. No matter how simple a re- ceiving set may be, or how modest the require- ments, there are certain essentials which must be provided: The correct aerial, the proper ground, a means for altering the wave length, an instrument for r hanging the radio frequency, audio fre- quency, and the correct telephone receivers. The large half-tone shows Harry Luckert, of New York, who Is using his bed spring as an aerial, and a very good aerial this useful domestic ele- ment makes* Mr. Luckert was refused permission to erect an aerial on his roof — and utilized his bed. He has accomplished surprising results, bearing WWJ, Detroit; KDKA, Pittsburgh; WGY, Schenectady, and WJZ, Newark. He Is using, as may be seen, a one-tube receiver of the regenerative type, consisting of two vario- meters, and a vario-coupler. This set is carefully shielded and he claims his results are due largely to this, admitting, however, that his location is apparently favorable for long-distance reception. The smaller half-tone shows the rear view of the set with Mr. Luckert's finger flirting to a variometer. This set is small and very compact Digitized by Google

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RADIO WORLD 11 Latest Important Radio News of the Week IN Missouri a movement was started recently for state control of broad- casting. This movement is showing signs of spreading to other states, and it was the radio interests of Massachusetts that suggested the confer- ence here between the radio and motion picture people. It was believed that the best time to hold the conference was during the Chicago Radio Show, the first manu would be here. "Listening In,1 by Carlyle Moore, in the out of Dr , Abrams resigned from that association. Dr. Abrams says i things are radio-active and that sufficiently delicate apparatus can the degree of radio-activity and determine a substance being examined with- out even seeing it. Dr. Abrams says ha has devised such a sufficiently "A drop of blood," said Dr. Abrams, "with its billions • • • With the work of Installing a large radio broadcasting station at Police Headquarters, New York, the We, The Hague to London, thus following the example gi American enterprise and initiative have supplied the Exchange with direct cable communication to New York Dr. Albert Abrams, of San Francisco, of diagnosis and treatment of disease that missing parsons can be located by radio. originator is la New Dr. of the electronic York. He claims Abrams visits the East, In E. F. W. Alexandarson, invert expected from Sweden next month. What a Microphone Looks Like TWO buttons, or carbon granule chambers, characterize the West- ern Electric microphone used in WBAY, New York. One button is located on each side of the vibrating diaphragm, so that at any given point in the vibration one button is compress- ing carbon granules while the other is releasing pressure. This means that current flow, affecting the voice trans- mission, is being increased on one side of the diaphragm and decreased on the other. Every fan who has studied the action of the single-button microphone knows that its results are not exactly proportional to the amplitude of the sound waves producing them. Some distortion takes place. With the two- button device this distortion is cut down tremendously. The two buttons of the microphone are connected with one side of the transformer — or in telephone language, the repeating coil- in such a way that the resulting cur- rents are both in the same direction and their combined effect is the pro- duction of waves that are quite free from distortion. The electrical equipment is so ar- ranged that another type of transmitter may be used when desired. It is not a microphone at all, but what is gener- ally known as a condenser transmit- ter. It contains no little cups of carbon granules which characterize the microphone although it has a vi- brating steel diaphragm and makes use of air damping. It requires considerably more preliminary am- plification than the microphone but it has certain characteristics which at times makes its use desirable. He Had Something to Brag About! Radio Bug:-"Son. I can t brag about your quality or modulation. Digitized by Google

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12 RADIO WORLD B battery of Hi* nan-variable type. The Radio Primer Weekly ABC of Radio for the Beginner, in which Elementary Facts and Principles Are Fully and Tersely Explained By Lynn Brooks battery. It is capable of being re- charged after exhaustion by passing an electric current through it in a di- rection opposite to that of the current of discharge. This difference consti- tutes the principal advantage of the storage battery over the primary bat- tery. * * * How is the electrolyte generally used? The electrolyte consists of a weak solution of sulphuric acid which per- mits ready conduction of the current from the primary battery. The greater proportion of acid, within certain limits, the smaller the resistance of- fered. * * * What is the effect of the current passing through the electrolyte? It decomposes the water into oxy- gen and hydrogen. This is indicated by the formation of bubbles on the exposed surfaces of both plates. These bubbles are formed by oxygen gas on the plate connected to the positive pole of the primary battery, and hydrogen on the plate connected to the negative pole. * * * How is the electrolyte prepared? One part of chemically pure con- centrated sulphuric-acid is mixed with several parts of water. The propor- tion of water differs with several types of cell from 3 to 8 parts, as specified in the directions accompany- ing the cells. * * * In preparing the electrolyte, how should the water and acid be mixed? The mixture should be made by pouring the acid slowly into the water. Never do it the reverse way as an accident will result. It cannot be too strongly stated, in mixing the liquid, This larger size of battery. aUo a B battery, is known as the variable type. This battery can be used where a chance of voltage Is required. ■JT /HAT is the variable B-battery l/y used for? How can you tell * it from any other batteries? The variable B-battery is used in conjunction with the plate of the tube to carry out the principle of making the tube function. The positive pole of the B-battery is connected always to the plate of the vacuum tube whether the tube is a detector or an amplifier. If, by accident, the negative connection from the B-battery is con- nected to the plate the tube will not function at all. The B-battery is a necessary element for the tubes and may be detected easily by their sizt. The accompanying illustration shows what the variable B-battery looks like. It is much smaller than the storage battery. The variable taps are brought out on the top of the battery. * * * Are there any non-variable B-bat- teries? Yes — B-batteries of the non-varia- ble type. They are the same size, carry no taps, have a constant voltage and can be used with fixed voltage. * * * Describe the storage battery. A storage battery consists of a num- ber of cells, each cell made up of a number of plates and grids in an elec- trolyte solution of such character that the electrical energy supplied to it is converted into electrical energy — a process called discharging. * * * What is the theory of the storage battery? The action of the storage battery is practically the same as that of the primary battery and is subject to the same general laws. The cells of a storage battery are connected in the same way as primary cells and, when charged, are capable of generating a current of electricity in a manner sim- ilar to that of the primary battery. It differs, however, from the primary THOUSANDS of radio beginners have come into the radio field since sum- mer. They will find "The Radio Primer," published weekly in RADIO WORLD, a regular source of instruction end aid. For this reason, RADIO WORLD will repub- lish, from time to time, some of the valu- able primer articles that appeared in its early issues. These articles, by experts, contain a vast amount of radio informa- tion that cannot be duplicated. Every be* ginner will find them necessary to the building of sets and cooperative with the new material being printed weekly. that it should be stirred with a clean wooden stick, the acid being added slowly to the water. The acid is cor- rosive and will burn the flesh. Dis- tilled water should be used in prepar- ing the solution. The mixing of the two ingredients causes them to become very hot. * * * How should the cells be filled? Sufficient of the electrolyte should be poured into the jars to either com- pletely cover the plates or to come within half an inch of the top of the jar. Large cells should be filled by means of an acid-proof pump. During this operation wear rubber gloves. * * * What about the density of the elec- trolyte? It should never exceed 1,300 when the battery is fully charged. * * * What should be done with the old electrolyte? When a battery is taken down, the electrolyte may be saved and used when reassembling the battery, pro- vided great care is exercised when pouring it out of the jar not to draw off any of the sediment. It should be stored in convenient receptacles, pref- erably carboys which have been thor- oughly washed and never used for any other purposes. * * * What is the voltage -of a secondary cell? This depends generally on the dens- ity of the electrolyte, the character of the electrodes, and the condition of the cell. It is independent of the size of the cell. * * * What are the colors of the plates? In the case of formed plates, and before the first charging, the plates that are positive are of a dark-brown color with light- or red-gray spots, while the negatives are of a yellowish gray. These spots, on the positive plates, are small particles of lead sul- phate which have not been reduced to lead peroxide during the process of forming. They represent imperfect sulphation. Digitized by Google

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RADIO WORLD 13 Regenerative V-T Receiver for Short W7riTri=*o Describing Photographs VV dVCo Front Cover of This Iss By Fred. Chas. Ehlert on Issue AMATEURS are asking con- stantly : "What is the most effi- cient hook-up, or diagram, whereby loud signals may be ob- tained?" The tube detector undoubt- edly is the most sensitive detector yet devised; but a new circuit has been created, to be used with the vacuum " tube, which will render the tube self- amplifying. This is the regenerative circuit. A vacuum tube, when hooked-up to a special circuit, will generate oscilla- tions whose frequency can be con- trolled by varying the capacity and in- ductance of the circuit. The inventor of this circuit is Major Edwin H. Armstrong, U. S. A. He has con- tributed what is universally acclaimed as the most important invention since radio was first discovered. One type of a circuit where regeneration can be produced is shown in the accompany- ing circuit, whereby variometers are employed to produce that effect. All regenerative circuits are delicate to operate for the regenerative effect which gives rise to all kinds of noises in the telephone receivers. The equipment needed for this cir- cuit are two variometers, one vario- coupler, grid condenser and leak, tube socket, and tube detector, with batter- ies and phones. This circuit is a short-wave regen- erative circuit employing the vario- meter in the plate circuit for produc- tion of such regeneration as that of Major Armstrong's invention. L-l is the primary winding of the vario- coupler and L-2 the secondary of the vario-coupler. In series with the pri- mary is a variable condenser, but this is to be "tried out" to see if it is need- ed. Personally, I believe it should be left out A grid condenser and leak is shown which should be connected in series with the grid of the tube. This grid condenser has a capacity of .00025 mfd., and may be purchased at most any radio shop. The 22-volt battery is connected in the plate circuit of the tube with the plus side of the battery connected to the plate of the tube. One side of the filament of the tube is connected to the wire running from the telephones to the grid variometer. Be sure that the 6-volt battery is connected in right. Before making connections, be positive that the battery leads are correct. If the leads from the 22-volt B-battery become crossed with the filament of the tube, don't be surprised if your Grid Condenser^ j^^^r Grid Leak* I . . . . - ^ I Vano' Coupler 'B'botteryJ yrGrid Variometer Si heaaa tfc dtaanun ot a enaiplOa regenerative receiver larujilnj lea la placed hi the «rl* circuit while the ether variaaaetar is vacuus* tube, Thia receiver will reapead to the aharf wave* ■ Succeated by Fred. Chas. Ehlert. Dream by 3. Ne tube does not light. This means that you have a burnt-out tube and that another tube must be purchased. But be sure that all connections are right before lighting. The rheostat in series with the tube which controls the filament lighting of the tube is also shown. In case it is turned too high, the tube also will burn out. These precautions will have to be taken care of, but aside from this, there is not much to worry about. Generally the socket for the tube is marked as follows: P, for plate; G, for grid ; F plus and F minus for fila- ment. These two F marks are to be connected to the 6-volt storage bat- tery. Be sure to connect them to the proper polarity with the rheostat In working this set, you will learn by experience when lighting the tube that it will start to hiss. The most sensi- tive spot is just below where the tube starts to hiss. Again I caution you not to turn the filaments too high, as probably they will burn out the tube. By keeping the filaments at their proper brilliancy the tube's life will be lengthened. By using the tube you will soon learn its great advantages over the crystal de- tector. WJZ Celebrates First Anniversary WJZ, radio call-letters on the lips of thousands of radio enthusiasts, held its first anniversary services during the evening of October 5, when several of the artists who broadcast from WJZ last fall again visited this station. It is generally regarded that KDKA is the father of broadcasting; also that WJZ popularized the broadcasting idea and introduced it in the Metropolitan area, where it attracted the best of talent and. with the assistance of N'ew York radio publications, aroused the nation to the great possibilities of radio broad- casting. WJZ was officially opened October 5. 1 03 1 . at 1:55 p. m . when several records were played to enable the radio audience to tune in their radio sets to receive, a few minutes later, the play by play re- sults of the World Scries. The response to the broadcasting by WJZ was immediate, as suggested by letters received from Massachusetts. West Virginia. Ontario, Pennsylvania, N'ew York, and New Jersey. The first artists to broadcast in person were: The Shannon Four, well known recording quartette, consisting of Charles Hart, tenor; Elliott Shaw, baritone: Wil- fred Glenn, bass, and F.ouis James, tenor. Soon thereafter the foremost re- cording team. Billy Jones, tenor, and Er- nest Hare, bass-baritone, entertained the growing invisible audience Two promi- nent instrumentalists. Constance Kar!a. violinist, and Anna Welch, harpist, fol- lowed and other artists of note. Digitized by Google

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14 RADIO WORLD ) Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengths for the Busy Reader. <C. Central News Photo Service.) Sir Thomas Upton as ha appeared Just after talking, by radio, across tha Atlantic. The instrument at his left is the transmitter, or acousticon, into which he apoka, and which started his words on their long journey to London. Commenting on the experiment, Sir Thomas said: "This is the biggest thing of its kind in the world—and worthy of America as a big part of this world." AT WOR, the broadcasting station of L. Bamberger cV Sons, Newark, New Jersey', an attempt was made, bat Saturday night, to bridge the Atlantic Ocean with the human voice. W. S. Moler, publicity manager for WOR, re- ported that a message had been received from Gordon Self- ridge, "the Marshall Field of London," stating that the voice was heard "more or less distinctly." The person who spoke into the transmitter at WOR was Sir Thomas Lipton, at pres- ent visiting the United States. Mr. Selfridge's cable also stated that a vocal selection was distinctly heard. According to Mr. Moler, this is the first time the human voice has been broad- cast such a distance, over a 400-meter apparatus. It was necessary to tune up to over 2,000 watts, or twice the ordinary capacity of a 400-meter outfit. Sir Thomas and a few friends went to Newark to make the experiment. The radio message was sent to Mr. Selfridge at Marconi House, London. • * * Consul Wesley Frost, Marseilles, states that owing to gov- ernmental restrictions the development of amateur radio clubs in France has been so retarded that up to date there have been few in existence outside of Paris. The Radio Club of France has' recently established its first branch office at Marseilles, and its local representative has offices at 44 Rue des Abeilles and in the grounds of the French National Colonial Exposition. * * * Sweden sent missions to England, France, Germany and the United States, two years ago, to study the various wireless systems and types of apparatus in use. In 1921, the mission, under the direction of Seth Sjungquist, head of the Royal Telegraph Administration of the Kingdom of Sweden, visited America to inspect the high-power station of the Radio Cor- poration and to particularly see the Alexanderson alternators in operation. When the Reichstag met this year it sent a spe- cial legislative committee to England to study the vacuum tube as developed there, and it was only after hearing this report that the Reichstag recommended the use of the Alexanderson alternator and authorized the signing of the contract by the Telegraph Administration. * • • The installation of small radio outfits in all lighthouses of the Department of Communications, Mexico, is to be given a trial. Two sets are being supplied, after which, if the results are satisfactory, all lighthouses will be similarly equipped. * * * The announcement, "Flowers sent by radio," is made by a Bond street, London, firm of florists. "Altogether we have 2,300 agents," said the manager of the firm, "and flowers can be delivered in all parts of America and Canada in a few hours. The idea is spreading rapidly in England, though we receive more orders from the other side than we send." * • * The latest use of radio is to locate missing relathree. Ama- teurs are requested to send out general or QST calls contain- ing complete descriptions of the person missing with such other data as may be given them for broadcasting. * * * An interesting innovation in broadcasting was Started last week at station WLW, Cincinnati, when Paul Briol inaugurat- ed a tri-weekly book review by radio. Books by the best authors of the present were reviewed briefly and interesting anecdotes regarding the authors were read. This feature will be worked into the evening programmes on Tuesday, Thurs- day, and Friday nights. * * ♦ For the third time, American radio amateurs plan communi- cation with continental stations using their own amateur sets. This year's transatlantic tests will be conducted from Decem- ber 12 to December 31 by the American Radio Relay League in cooperation with the amateur organizations, in Canada, Eng- land, France and Holland. » » * English manufacturers have organised for the purpose of building and operating broadcasting stations with the approval of the government. Special wave-lengths will be alloted and stations will be erected in various areas, so that the whole territory of England will be well covered, and yet no interfer- ence will be experienced. By following a systematic method of locating stations and distributing wave lengths, the English will not have to suffer the early inconveniences which accom- panied the advent of broadcasting in this country. * * * Secretary of Labor Davis started broadcasting, on October 2, for the Department of Labor through the Naval Air Station at Anacosta, NOE. The service will be for three fifteen-minute periods each week from 7:15 to 7:30 every Monday, Tuesday and Thursday. Secretary Davis, in his first broadcast, pre- sented a short exposition of what the Department of Labor can do and is doing for American wage earners. A definite program will be announced later. * * * Sunday religious services have been added to the weekly schedule of WGY, Schenectady, New York. Every Sunday, a Schenectady church will be connected to the radio transmit- ting-outfit by land wire and the entire service of that church will be sent out, beginning at 10 :30 a. m. At 4 :30 o'clock, every Sunday 'afternoon, vesper services will be held in the studio of WGY, and a short address will be delivered. * * » W. K. Vancterbilt has departed from Southampton, England, on his new motor-yacht, said to be the most costly and lux- urious pleasure craft afloat. Her radio apparatus, it is re- ported, is as powerful as that of any of the transatlantic liners. * * * The first radiophone exchange in the world, installed by the Air Ministry, is in daily use at the London Air Station, Croy- don, England. Its main purpose is to connect the aerial-traffic controller with the pilots of airplanes operating between Great Britain and the Continent. Digitized by Google

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RADIO WORLD 15 Radio and the Woman Crystal D. lector I AM not unmindful of the fact that radio has me on my toes most of my walking hours— and, perhaps, more of the hours when I should be asleep than my doctor would ap- prove—but even after a night with the "owls" I feel as chipper and gay as if I had set up counting an unexpected legacy. Most everything can be overdone. A plethora of riches pro- duces nausea. One can have too much of a good thing, and all that; but I have yet to become bored by the varied ex- citement that radio throws in my way. • * # The other night, for instance, I attended a radio party down on Long Island. The hpstess was one of the most charming young matrons of New York's very charming set. She sent out cards for a hundred guests. "You are invited to a radio evening," was the simple but alluring phrase in the corner of the invitations. Of course, I had the usual argument get- ting Friend Husband to put on his evening togs. He swore the weather was still too warm and made other petty excuses, but I had my way. Luckily some dear friends motored us Our hostess has one of those huge country homes that make one positively jealous. Her big living room, — I suppose I should be "class" and call it a "reception room"— where the chairs were arranged in a semi-circle before a radio-set banked with flowers. All one could see were the tuning knobs and the huge loud-speaker jutting forth from a mass of pink roses. When the music and the, vocal selections be- gan to come through, the scene was unusually attractive. I believe that it was the first affair of its kind ever held in America. If there have been others I have never heard of them — and if any of my readers can enlighten me, I wish they would write. The programs rendered that evening were particularly fine. Only one number— a violin solo — seemed to suffer until a few turns of the dial and when the minimum of volume was reached, everything was perfect. Believe me, there was not a bored person in the room. Every one remained seated until the time tick came through from Washington, and all con- sidered it quite a novel thing to see if their timepieces were correct. * * * The broadcasting programs over, a supper was served. While this was the "matter of the moment," the chairs in the reception room were removed and the floor made ready for dancing. And — after some maneuvering, during which dozens of men, who never before had taken even the smallest interest in radio, peered into the set and asked a thousand questions— we picked up dancing music being broadcast from St. Louis' Imagine the charm of itl Dancing on Long Island to music being played in St. Louis. I wish I had the space to give more than this mere outline of this very attractive affair. But I can drop a hint to all hostesses who are looking for something new this winter in the way of entertainment: Give a radio party. If you want some inside suggestions, drop me a line and I will help you all I can. * * * I have had a rather big "mail" since my last "copy" was written for Radio World. One of my correspondents who requests me to withhold both her name and her address, be- cause her husband would "never forgive her" if he knew that she wrote to me, wants to know if iron pipe may be used for stays on an aerial 40 feet high, or is iron pipe obstructive to radio waves. Listen, dearie — and don't tell your husband- but iron pipe may be used for poles to support your aerial, but it will absorb some of the radio waves. Wood is better. Heard Atlanta, Georgia, in Des Moines, Iowa EDITOR, Radio World : In Radio World of September 23, page 29, "Who Is This Broadcaster?" I heard this pro- gram very plainly, and as I have been keeping a radio log I find that "Little Red Riding Hood" was given by a woman, in a child's dialect, from the broadcast station WSB, the "Atlanta Journal," Atlanta, Georgia. I heard this program which started at 10:45 P. M., and ended in the morning; for when he signed off the operator said, "Good morning." As a rule, WSB is very clear here and everybody here looks to 10:45 as they know Atlanta, Georgia, will come in no matter how bad the weather is — static or not. This program was received on one-step single circuit using an A-P de- tector and one 301-Cunningham, ampli- fied bulb. The outfit is home-made. Hoping this information will help out radio fans. — Jack Clemons, Des Moines, Iowa. * » • Also in Cleveland EDITOR, RADIO WORLD: On Aug- ust 16, 1922, at 1 A. M., we received the message, and commented on the hour for a bed-time story and we heard the entire program. It was from Sta- tion WSB, Atlanta, Georgia.— Mrs. W. C. Blackburn, Cleveland, Ohio. Only Relative Values Always remember that the divisions and markings on dials and switches have only relative values, and do not directly indicate wave-length. They afford an easy means of resetting your instruments to tune in to a certain station. New York Hotel Phone Operator Now Answers by Radio Here ia Mis. Mllie Cullingan, telephone operator of the Vanderbilt Hotel, New York City, who »u not content to remain the operator of an ordinary switchboard, but eo familiarized herself with the radio system installed in the Vanderbilt that she is able to operate • set to perfection. Radio is fast becoming an essential of the leading hotels and hotel systems of the East. In general, it is now used for pacing- guests. During the past week, when New York City was crowded with guests owing to die World's Series and Banker's Convention— a number of hotels installed temporary radio sets to keep their guests in touch with the latest Digitized by Google

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If) RADIO WORLD Interesting News Photoi Collected for Busy (C. Central News The DM you haw the am of the World's Series Baseball played at the Polo (rounds. New York? Here is tha room from which it was broadcast, play by play. J, C. Smith is tha operator who is "shooting" tha news to the not get seats for the bis event. The world's greatest radio station is opened, and here is a ha] hustling commercial institution, and so it is, for it is the get America Station, situated nt Rocky Point, near Port Jefferson, 1 of all the world. From It, President Harding flashed radiograms a part of tha receiving room into which aaaaaagee are delivered fa recording code moss ages. Radio Central, aa tha big station is k of separata transmitters so aa to ensure simultaneous commu at the Rocky Point Station enable the powerful transmitters to modulate, or control, tha flow of power from tha alternators to employed at Radio Central. It consists of a line of 410-f (C. International Newsrael Photo) Clam Kimball Young, famous motion-picture star, talking over the transmitting apparatus of "The Examiner," Los Angeles. On this occasion Miss Young recited the late James Whltcomb 'Riley's poem, "That Old Sweeth. ■ t of Mine," and aha received letters from radio fans even In the Middle West who h< The apparatus at her right is a Sa-watt radiophone. Digitized by Google —

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RADIO WORLD ttraphs of the Week yRadio Readers of its bur one*. It looks like the office oi ■ i la Now York City of tha Radio Corporation o Digitized by- Google

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18 RADIO WORLD Bearing /ntticalor. .SB 66 c51 6, Induction Coil 63. ^ rH*IMI ^ - diajrrams of Mr. Sperry'* invention, the chief for cauifnj an Indicator, by m automatically the movement* of Wireless Repeater System No. 1,<2S,S«7. Patented, September S, US. Patentee: Elmer A. Sperry, Brooklyn, N. Y. THIS invention is for the purpose of automatically transmitting the read- ings of an indicating member by wireless to a distant point. It is particularly use- ful, the inventor claims, in automatically transmitting by wireless to an aircraft or other distant point the readings of a compass, fire-control instrument, or other indicator on a ship, whereby the ship's heading, or the bearing of a target ob- served from the ship may be constantly Circuits for Electron-Dis- charge Devices No. 1.4M.7S4. Patented, Auruet 22, 1922. Patentee: Robert C. Mathes, New York City. THE sources of direct current potential for the input circuit of an electron- discharge device of the audion type, is the basic element of this invention of Mr. Mathes. It is intended to provide of which le to provide simple of radiant Impulses, to fallow ' at a distant point. communicated in safety to a distant point. Such a system has especial uses in the aerial ordnance-control for heavy guns where the target is only visible from air- planes, which signal to the ship or other firing station the bearings of the target In such a system, it is very desirable that the airplane pilot should know the bear- ing of his object. The chief purpose of Mr. Sperry's in- vention is to provide simple and efficient means for causing an indicator, by means of radiant impulses, to follow automat- ically the movements of another indica- tor at a distant point. • * a more convenient and desirable method than has heretofore been used for se- curing a desired difference of potential between the filament and the grid of a tube of the audion type. A further ob- ject is to furnish a method and means for compensating for fluctuations in the potential of the output circuit battery of the vacuum tube. Specifically, these objects may be real- ized by the indirect use of the heating battery, or of some other source; but in either case associating this source with the output circuit battery. It is well known that tat current flow- ing through the output circuit undergoes fluctuations owing to sudden or gradual internal changes within the power bat- tery. Such fluctuations in the space cur- rent of the vacuum tube are very troublesome. The method by which this invention overcomes this error may be explained as follows: Assume that the vacuum-tube circuits are so arranged, as hereinafter described, that the current for the input circuit comes from a source in series with the source for the output circuit. For illustration, suppose there is a decrease in the potential from the output circuit battery due to some in- ternal change; this will necessarily tend riq.l. n9. 2. Schematic diagrams of the invention of Mr. Robert C Mathes for tha diechartv of electrons. to decrease the space current between the filament and anode of the vacuum tube. If the input and output batteries are of similar nature, this change, in all probability, will also decrease the potential of the input-circuit battery, which is in series with it, so that the' grid potential will become less negative thereby tending to increase the space current to its former value. The com- pensation would take olace in a similar manner for an increase in the voltage of the batteries, due, for instance, to the batteries being charged by some suitable means. This scheme works especially well if the negative grid-voltage is derived from the drop of potential across the terminals of a resistance, which derives its current from a battery associated with the out- put circuit battery. Yon Will Need RADIO WORLD as a Radio Reference Be sure to see that your file of RADIO WORLD is complete. There will soon be so great a demand for back numbers that the supply will not be sufficient to cover it. RADIO WORLD has been issued every week from April 1 to date. Start with No. 1.— RADIO WORLD. Mail, postpaid, for 15c a copy; any seven copies for $1.00. Or send $6.00 for one year (52 issues) and have your sub- scription start with No. 1.— RADIO WORLD, 1493 Broadway, New York City. Digitized by Google

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RADIO WORLD 19 At the Radio Shows Coming Events The editor, of RADIO WORLD will gladly fobllah mw« item* of all cootamplatsd nam •how* and sxposi" tnilinf full infont CHICAGO RADIO SHOW, Coliseum, Chicago, DJ., Octobi r 4 to 22. V.J. Hermann, managing director, 549 McCormlck Building. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, incluiiTe, 1923. George A. King, director of publicity, 417 South Dearborn Street, Chicago, 111. PERMANENT RADIO PAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION. Grand Cen- tral Palace, New York City, December 21 to 31, induHTe. Direction American Radio Exposition Company, 120 Broadway. TRI-STATE TOBACCO GROWERS' RADIO SHOW, Covington, Ohio, October 21 to 28, in- clusive. NEW YORK ELECTRICAL AND INDUS- TRIAL EXPOSITION, Grand Central Palace. New York City, October 7 to 14, inclusive. SPRINGFIELD RADIO EXPOSITION, Spring- field Auditorium, Springfield, Mass., October I to 7, inclusive. SOUTHERN CALIFORNIA RADIO 8HOW. Combined exhibition of the Southern Cali- fornia Broadcasting Association, the Southern California Radio Association, and the South- ern California Radio Trad* Association. Lot Angeles, October 0 to 14 Inclusive. INTERNATIONAL RADIO SHOW, Madison Square Garden, New York City, November 20 to IS, inclusive. E. C Buchignani, director of pub- licity. A Warning to Radio-Show Exhibitors AS to the value of radio exhibitions: Radio expositions are all right in their way. They have a legti- mate place in radio affairs— BUT THEY MAY BECOME A NUSIANCE AND A MENACE UNLESS THE INTER- ESTS OF THE TRADE ARE PROP- ERLY SAFEGUARDED. Radio exhibitions, organized and con- ducted with an honest regard for radio art, science, and business, are excellent things. When ran on go-as-you-please principles by promoters who have noth- ing in mind except the sale of space to exhibitors, they are likely to do much more harm than good. For instance, how many of us hava visited radio expositions and been con- founded by the din and noise, by the bar- rage of unrestricted announcements and the cannoading by batteries that filled the air with meaningless sounds, making the would-be enthusiasts wonder what it all was about, and sending them out into the night filled with the idea that radio is a noisy, senseless thing. A properly regulated method of re- ceiving and sending messages in con- nection with radio shows and in making business and official announcements, would greatly lessen the resentment of the judicious, and this could, and un- doubtedly would, be regulated if prac- tical radiomen had anything to do with the actual management of the show. Therefore, Radio World ISSUES THIS WARNING TO MANUFAC- TURERS of radio goods and to all others interested as radio exhibitors: Don't sign up for space at the next radio show whose representative calls on you for a reservation of space unless that representative can prove positively and convincingly that the board of manage- ment contains the names of practical radio men. Even then be sure that these radio men will have something to say about the ACTUAL RUNNING OF THE SHOW IN ALL ITS PHASES. Beware of the radio show promoter who hasn't any more interest in radio than he has in canned milk or type- writers. RADIO SHOWS SHOULD BE RUN BY RADIO MEN. Until they are, the radio industry and our constantly grow- ing army of fans" will not get a square deal. — The Editor. Chicago Radio Show THE Chicago Radio Show, the first show ever endorsed by the National Radio Chamber of Commerce and the Radio Division of the National Electrical Manu- facturers, promises to be one of the largest trade expositions ever held. When the doors of the Coliseum are thrown open to the public on Saturday, October 14, prac- tically every large manufacturer of radio apparatus will be represented in the show, which will continue until Saturday, Octo- ber 21. It will be open to the public both afternoon and evening for the eight days. It will be the first time that the manu- facturer has taken the opportunity to meet the jobber, dealer, and public at the same time. Ed Wynn, the famous comedian, and his company, will put on "The Perfect Fool" the opening night for broadcasting. There will be a society night, a radio ball, a chil- dren's afternoon and other features during the week. While the entire Coliseum will be given over to the exhibits, the Coliseum Annex will be given over to meetings. General radio-trade problems will also be taken up at conferences of manu- facturers. One of these problems will be broadcasting. Many manufacturers believe that the industry is being held back by poor broadcasting, poor pro- grams, and a general lack of knowledge of what the public wants. Another problem to be discussed is, what is regarded as some, a boycott in England against radio apparatus made in the United States. James F. Kerr, business manager of the Chicago Radio Show, who recently returned from a trip to New York, Boston, and other Eastern cities, reports that not less than 127,000 radio sets, manufactured in the United States and shipped to England, are now being returned to the manufac- turers. The Eastern manufacturers were depending largely on their export trade. The Western manufacturers have been better off because the farm- ers of the Middle West are going in stronger than ever for radio and are making the market one of the busiest ever known. RadlO brings it MACHmJK A Radio tells it it with the wonder fUMMBsMsT Radio that tells itck and in full volume N tp all within re _ of its voice AFTER once using a Magnavox Radio, the Reproducer Supreme, you would no more go back to the telephone headset than you would exchange your electric light for a tallow candle. With the Magnavox Ra- dio, due to the electrody- namic principle involved in its construction, you hear every program or message at its best. A Magnavox Radio so in- creases the use and enjoyment of any receiving set that it is considered the one essential part of the receiving station. R-3 Magnavox Radio with 14-inch horn (here illustrated), is ideal for use in homes, offices, etc Prie* S4SJ6 R-2 Magnavox Radio with 18-inch horn for those who wish the utmost in amplifying power; for large audiences, dance halls, etc. Prie* S8&M Model "C" Magnavox Power Am- plifier insures getting the largest possible power input for your Magnavox Radio. AC-2-C, 2-Staga - - - • $MM AC-3-C, 3-Stag* .... 11«.M Magnavox Product) May Be Bat Of Good Dealer* Everywhere The Magnavox Company Home Office and Factory: Oakland, Cal. New York Office: SK Ssrstrth Arson. Digitized by Google

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20 RADIO WORLD Baseball at Home all Winter by Radio National League American League G'E RADIO Baseball Player board OUTS > 1 2 3 Teams 1 2 3 4 5 6 7 8 9 10 11 R. H. E. BALLS 1 Z 3 4 STRIKES 1 z 3 To operate this radio playarboard, cut out the email square* and the baseball* on either aid* of the diamond Past* then onto cardboard H possible. Then write in the name* of player* and their position. Five extra squares may be need for either team whan pinch hitter* or suhatitutm are pat in the lineup. The operation will then be much the same as on the electric player board* used in hall* to report ball gsmss Place the square containing- the name of the first man at bat on home. If he stearin*, more him to first and place the second batter on hem*. If one strike ia called, place one of the ha—hall* over the square marked No. 1 under STRIKES. If the next delivery Is a ball, place another of the baaobah* over the square marked No. 1 under BALLS, Advance these baa*- balls as the balls and strikes are called. When one Is out, place one of the baseballs over the square marked No. 1 under OUTS. A small dot may be placed in the square marked HITS and ERRORS aa these occur and at the doss of the half of each inning score the runs saade in the SCORE BY INNINGS apace. Take the principal players of the Giants and Yankees, or make up your own teems, and following the runes as they were played at the Polo Grounds, or any other games, you can have baseball at home all winter. SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Pitas* send me RADIO WORLD for 1493 Broadway, New York City. months, for which please fad enclosed % SUBSCRIPTION RATES: •ingle Copy t 45 Three Months 1.50 81a Months 3.00 One Year (52 Issues) 6.00 Add COO s Year for Foreign and Canadian Posts ge From Pole to Pole THE modern school-boy knows radio from A to Z, and can rattle off the terms with a fluency that staggers the casual dabbler in the new art. In some sections of the country, however, only rumors of wonders of radio have seeped in and the native isn't always quite sure what it is all about. In Bleecker, a little hamlet near C-loversville, New York, a progressive farmer was erecting poles for his aerial for the purpose of getting crop reports and weather forecasts from WGY, the General Electric Company's broadcasting station at Schenectady, New York. A neighbor happened along and learning that the work had something to do with radio asked: "Which pole does that feller sing off of?" Digitized by Google

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21 Ohm Sets $3.98 Satisfaction Guaranteed or Money We mall pbonra the day your order arrives. Every pair tested, matched and guaranteed aa ia $8 to 110 Seta. Circular Free. Tower Mfg. Company HI STATION ST BROOKLINE. RADIO FANS Perfection in RadicT r Headsets dt rained in "ICSSO HEADSETS give clear, distinct tones, reproduce perfectly the most sensitive radio sig- nals in music, speech and code. No matter how perfect or ex- pensive your apparatus; no matter how strong or perfect the waves; without "ECHO HEADSETS" your results can- not be perfect. We ship phones the day your order arrives. Every pair tested, matched and guaranteed as sensitive as the most expensive headsets made. Sold with money-back guarantee. Sent C. O. D. by express, who will hold money for 48 hours' tried, if not satisfied express com- pany will return money. S. Pearson RADIO Co. 142 Maple Street Richmond Hill Long Island, N. Y. Complete Radio Station for Rent THE Navy Department is offering its radio station at Miami Beach, Flor- ida, for lease to the highest bidder, pend- ing the enactment of legislation author- izing its sale. Bids will be opened at the Central Sales Office, Navy Yard, Wash- ington, October 17, 1922. NGE, the sta- tion, is completely equipped and, on 1620 meters, has a radius of about 300 miles. The site comprises 13,650 square feet on Miami Beach, and includes an operat- ing building, bungalow, storehouse, steel antenna-towers and complete radio-equip- ment. The operating building is built of terra cotta faced with stucco, contains machinery, operating, store and wash rooms, and an office built in 1921. The operating room is modern, being sound proof and copper-screened on all sides. The bungalow contains six living and sleeping rooms, suitable as quarters and fully equipped for the radiomen of the station. Two steel towers, 210 feet high, sup- port the large L-type and shorter T-typc aerials, both of which are said to be in good condition. The equipment includes a rotary spark- gap transmitter, generators, motor gen- erators, switchboards, transformers, pro- tective devices, condensers, loading coils, instruments, tools, and batteries; even clocks and typewriters. Bidders, who are required to be of the Caucasian race, must make an offer of a yearly rental, not to exceed five years, and forward three months' rental in ad- vance. The successful bidder must fur- nish a $25,000 bond to the Navy.

At Your Service! There appeared in Radio World dated April 1,15, and 29 the following articles : April 1 — A 500-Mile Radiophone Employing a 5-Watt Tube, by Frank A. Hahnel. "Tell Me, Please. How Will This Set Receive?" by E. L. Bragdon. Short Cuts in Receiver-Cir- cuit Design, by O. C. Roos. Making a Short-Wave Regenerator, by Fred. Chas. Ehlert. April 15— First Principles of Elec- tricity as Applied to Radio, by John P. Miles. Your Storage Battery, by E. L. Bragdon. What Makes Radio Pos- sible, by Edward Linwood. Ground Connection as Vital as Antenna, by Fred. Chas. Ehlert. April 29 — Valuable Pointers on Aerial Construction, by Edward Lin- wood. What Is Meant by Tuning, by E. L. Bragdon. Radio- Frequency Amplification and Regeneration, by Frank Armstrong. Honey-Comb Coils and Condensers, by Edward Linwood. Charging the Storage Battery, by E. L. Bragdon. How to Construct the Variocoupler, by Frederick J. Rum- ford. Each copy sent on receipt of 15c. per copy, or the three copies for 45c. ; or better still, send your subscription beginning with any one of these num- bers, and we will send this paper for 52 issues, and you will then have a complete file for ready and constant reference. Radio World. 1493 Broad- way, New York. "RADIO" VARIABLE CONDENSERS These condensers are the Standard of Quality. Carefully tested, inspected, balanced and adjusted to give maximum satisfaction. 3 plate V< $1.50 Special diacounta to Radio Cluba. Jobbers and Dealers write or wire for the biggest prop- sition in Radio— TODAY! FREDERICK H. PRUDEN INCORPORATED LERNER BUILDING 993 Bergen Ave. JERSEY CITY, N. J. Digitized tjy vCoogle

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $15000 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 WOULD. Radio Goods that Stand the Test i, Mod • napU of your goosU to oar Technical Editor, Fred. Ourise Eklsrt, MM Qiiimi, Lam Und, N. Y. It wll W oanfulty tooted mod K— d. If roar gllis ts, RADIO WORLD'S osdorsssi — t wOl be poOrthetod In aw mswrfcooslso lifiilssisl or -^b-*»— of any Und on year port. This U ■ frao service an too port of RADIO ao senesosa whatsoever on too port of the ssaasifactnror. anopt to* sassnsw of Vermica Variable Condenser {Manufactured by C. S. Cherpeck, 3125 Davlin Court, Chicago) A GOOD and Inexpensive variable condenser la now being placed on the market. By meam of a ipecial screw-adjustment, fine, ac- curate tuning 1* made possible. In fact, with only a alngle knob, or dial, what la eaaentlally vernier control la obtained. Another feature of thli condenaer la that it can be knocked about without being pat oat of order or having lta efficiency Impaired. Thli makea It a handy and Ideal piece of equipment for experimental, amateur and gen- eral radio work. Ita capacity wai found to be .0006 mfd. Ita convenient site makea It readily adapt- able for either table or panel mounting. It can be mounted on any else panel up to half an inch. The Vermica Variable Condenaer Is neat and attractive. • • * Correction In RADIO WORLD, Vol. II., No. 1, dated September SO, In the published teat of the "P-T" Ultra-Sensitive Crystal Detector Con- tact Wire, the address of the manufacturer was Incorrectly given. Address : "P-T" Crystal Contact Co., Box 1641, Boston, Mass. of bio Excellent Vernier Variable Condenser (Manufactured by Frank P. Marsh, 50 Linden Street New Haven, Connecticut) AWBLL-CONSTRTJCTED variable conden- ser of the vernier type. It has 23 plates with three end-plates to make up the vernier condenaer. Ita capacity was found to be .00056 mfd.. employing the 28 plates, while with the vernier alone the capacity was approximately .00007 mfd. The construction of too condenser Is as follows : Bud plates are of bakellte, with edges and facea polished. All plates are of the best grade even-gauge hard aluminum with edges cut to allow no burrs. The movable plates are mounted on a solid brass shaft ac- curately spaced and locked to correct position. The vernier which Is a handy element of this condenser is made up of three plates with the center plate movable. It Is a two-knob con- trol, one knob controlling the condenser ad- justment while the other knob, located In the center of the condenser knob, Is used for the vernier adjustment. This enables the operator to adjust his set for fine tuning of concerts and gives loud signals. The con- denser is nicely finished and when used in a set comprises a satisfactory condenaer ready for panel mounting. New Firms and Corpora- tions (The firms and corporations mentioned m these columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Radio Simplex Corporation, Wilmington. Apparatus. $6,000. (Delaware Incorporating Cqi W. W. Letts Service, Inc.. TJtlca, N. T. Manufacture of storage batteries. W. W. Letts, president and general manager; If. C. Welch, secretary and treasurer. Eclipse Radio Co., Geneva, 111. H. EL Krans, president and general manager; F. W. Krans, vice-president; J. Eric Anderson, secretary and treasurer. Machen Radio Mfg. Co., 4639 Bast Thomp- son Street, Philadelphia. North American Radio A Supply Corp., S Columbus Circle, New York, N. Y. Ship Owners Radio Service, Inc., New York City, has moved its Baltimore office from 17 South Gay Street to 11 North Butaw Street. Victor Radio Corp., 801 Bast 136th Street, New York City, Is appointing Jobbers to handle Its products. The Radio Chain Store Company. $120,000. Leon Abrams, Abraham Young, New York Clty^ N. Y., and Maurice Abrams, Newark, World Radio Corp., 423 West 65th Street, New York City. Wholesale distribution of radio materials and supplies. J. P. Johnson, general manager. Banker Enters Radio Business ARTHUR D. JENKINS has been appointed sales manager of the Tri-State Radio Com- Sany 826 South Meridian Street, Indianapolis, [r. Jenkins was formerly In the Investment- banking business in Chicago and New York, and for the past three years was connected with The National City Company, New York City. He has contributed articles to many of the leading financial magazines. He will have charge of the national exploitation to be carried on by the Tri-State Radio Company In the near future. H. G. Cisin with Dictograph Products THE Dictograph Products Corporation has acquired the services of H. O. Cisln, author of "The Radio Telephone Handbook." Mr. Clsin has been placed In charge of Dictograph Radio sales promo- tion, advertising and publicity. He was formerly engineering editor of "Electrical Record." Mr. Clsin Is a Cornell graduate, holding the degree of mechanical en- gineer and certificate of electrical en- gineer. Homcharger Now Operating Three Plants THE Automatic Electrical Devices Com- pany, Cincinnati, manufacturers of the "Homcharger," which has proved popular In the radio field, has been compelled to add a third plant to take care of the unprecedented demand for this device. The three factories, all located In Cin- cinnati, have a capacity of over 1,000 "Homchargers" a day, which. It Is ex- Dected, will enable dealers and Jobbers to obtain prompt shipments on their orders. C. Brandes, Inc., Goes into Canada p BRANDES, INC.. 237 Lafayette Street, ^* New York City, radio manufacturers, have organized a Canadian subsidiary, C. Bran- des, Ltd., and have leased a factory In Tor- onto, where work will commence as soon as alterations have been completed. In the meantime C. Perkins Ltd., Montreal, will rep- resent the company In the Dominion. Edgar Ryplnskl has been appointed resident manager. Radio Goods Active As Indoor Season Begins RADIO goods have seen enough ac- tivity lately to confirm the views of leaders in the business that the slump which occurred early in the summer was merely seasonal and that the business would return to its former scale in the fall, says C. F. Hughes, financial author- ity on the staff of "The World," New York. In other words, it appears certain now that radio is essentially a feature of indoor entertainment. A good deal of progress has been made in perfecting merchandise plans and in standardizing equipment. Retail stores are now offered the buying discount they were after and also may guarantee the various sets, which was another of their desires. V. T. SOCKETS Standard size, metal parts nickel plated, positive contact. Guaranteed satisfactory or money refunded. 21 cants each, 3 for 50 cents POSTPAID C A. HOLLISTER 254 Court Ave. Lyndhurst, N. J. NA-ALD DE LUXE V. T. OoaaMt snips at UsSssroi phosphor brass ones Snstr •ontaat ptaa. lo- ot nrhtha - M» trooblo peoablo. ftookot noojldod ! Ooodaoslt*. PibsUmIIj osbnoksblo. Wot ad slat, with utartar nlnteossMot hj hut «C duBjs or soldorlac iron. DMttl eliminated, aldlnc leeeullgu. Ifay bs asss for t Witt power tubs. HUbsst qmHtr throaihoot Prleo, TSs. Special proportion for dealer t and fobbert. ALDEN-NAPIER CO. Post. t_ 12 Willow St. Sprlncfielo, Moos. JUST OUT! 50 "VACUUM TUBE HOOK-UPS FOR RADIO RECEIVING CIRCUITS" Largest collection of V. T. Diagrams ap- plying to Radio Reception ever Published under one cover. Contains Latest on Radio Frequency sol Super-Regeneration PRICE PREPAID SUS W. A DICKSON m E. Fort St. Detroit, Mien. Digitized by Google

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RADIO WORLD 2' Radio Now One of the Greatest Assets of Shipping By fT. Randall SIR THOMAS FISHER, C. B. F-, R. N. (retired), general manager of Canadian Pacific Steamships, Ltd., London, who is now in America, says radio is one of the greatest assets of maritime service. "The most enthusiastic supporters of Marconi did not dream that radio telegraphy would develop to the extent it has during the past twenty years," said Sir Thomas to a representative of Radio World. "The usefulness and value of the new system of communication were soon apparent and radio was at once applied by the British Admiralty at Lloyds. The advancement of the science, insofar as it has affected shipping, has been great, and today no vessel of size is with- out wireless equipment. The question of safety at sea is undoubtedly the paramount benefit conferred by radio telegraphy; but other considerations, such as the facilities given for commercial and personal communi- cations, and the means provided for keep- ing passengers informed of world events, are of such vast importance that the con- ditions of ocean travel have been revolution- ized. "The highest standard of efficiency has always been maintained in the equipment of the ships of the Canadian Pacific fleets. Up-to-date improved radio installation is carried on all ships. The installation in a typical radio room, on the "Empress of Scotland," comprises a one and one-half- kilowatt quenched-gap transmitter, five hun- dred cycle, with normal daylight working range of 500 miles; one quenched-gap emer- gency transmitter with range greater than 100 miles ; a one and one-half-kilowatt con- tinuous-wave valve-transmitter which has worked a distance of three thousand miles under favorable conditions; type ninety-one four-electrode valve receiver; type one and twenty-seven piano tuner, and type one hun- dred and twenty-three hydrodyne receiver, capable of receiving signals of a wave length up to thirty thousand meters. Also a di- rection finding apparatus. "The Marconi operators aboard our ships tell many yarns about the efforts made by passengers to send the utmost in messages crowded into the fewest words. What is becoming a popular message is "Third epistle, St. John, verses thirteen fourteen," which, upon being decoded, if such a term may be used refers to the text: "I have many things to write but I will not with pen and ink write unto thee, but I trust I shall shortly see thee and we shall speak face to face." There are similar texts which convey explicit messages with a few words of wireless. "We are just a bit proud to be able to say that the Canadian Pacific was the first Canadian company to establish a daily all- Canadian news service for its fleet of steam- ships on the Atlantic, and that it maintains this exclusive feature for its passengers. The results have been very satisfactory. This news is made up daily by the Canadian Pacific at Montreal, from the latest press dispatches from all over the Dominion and is transmitted to all Canadian Pacific ships on the Atlantic. The Canadian Marconi Company erected a special press station at Louisburg, Nova Scotia, for the purpose of transmitting such news. "The Canadian Pacific is giving much at- tention to the importance of providing the latest radio direction-finding equipment on its ships, by means of which the position of a steamer may be quickly and accurately de- termined." Of course the public appreciates the fact that radio programs are free, but broadcasting free verse is carrying gen- erosity too far.— "The Evening Tele- gram," New York. UNIT RADIO SETS Our Pm City. PRICE and QUALITY our use11"1 Deteeter Unite Amplifier Ualta 11.00 to 11.00 Tuner Unit. II 00 DilKtv and I Step 10.00 Drfctor and 2 St-p 39 00 Oeteater and 3 Strp 11.00 Tunlni Unit DrtKtor and 1 Stop 01.00 1133 Immediate Delivery Radio & Electric Co. New York City KNOCKED-DOWN VARIABLE CONDENSER MONEY -SAVING PRICES ™^rU7at'"auT"«f w^"«*"dlt*WnT",FVl» luaranteed. Ultra beery aluminum plataa. Oee- Jena lie and plena. All atlMr rani nca.ll, nlrtel- 4 plated. Knea and painter Ineloderl rum I abed eeeembled ar tnaakad-dan at the fellawlat ■bled bj anrane Na. at M r D. Plate* CaparlW .00007 3 II II 49 .06025 .0005 .001 Lott'o Better Radio 473 ORANGE STREET NEWARK. M. i. GREWOL DETECTOR $2.00 Always Set and Ready Nothing Like It Nothing as Good The Orrwol Detector ha> takrn Ita plana ama the atandard nationally adrerll.r.1 parte. In elaaa br Itaelf b-r.u e It do-, wti ha* yrt been developed to do and a popular prlca. V.? Aiked for by name, told by reputation. If your dealer can net top fly yeu, send S2 tud we will fill ytur erder. Yeur Dealer he* GreweU GIn»» Encaird Super-Sen*. tiv« RANDEL WIRELESS CO. Solo United State Distributor! 9 CENTRAL AVENUE NEWARK, N. J. Reliable and Beautiful RADIO -A RE -CHARGER THE RADIO-A is a highly efficient dependable piece of apparatus, absolutely fool- proof, easily attached by sim- ply plugging into ordinary 110 volt lamp socket. In case of current failure, the unit cuts out automatically until current is resumed, without discharg- ing battery. It is designed expressly for re-charging radio filament bat- teries, but may be used for automobile or any other stor- age battery of reasonable size and capacity. Price, $18.50 Dealers and Distributors Here's a Winner! Write for full A compart portable Kr-rhanrlac Call that will full- rhartjo a 100 A. II. Bat- Irrjr oarrnlaht. for from Jr ler, ac- cord I nr to preiaillnc rates. LAST A LIFETIME King Electric Mfg. Co., Inc. 1681 FILLMORE AVENUE BUFFALO, N. Y. Digitizecftsy Coogle

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24 RADIO WORLD ^&ff^ Hard Rubber Composition DA NET Q ^Q5^ Conform to Navy Specifications I rtllaUl^lw A High Ptt't* Panel, GaaraatoaaJ Not to Warp, ami Drilled Cloaaly Without • Burr. Highly P olisbocl — Edaee Ground to Six*. Unailanl same, TsltxS/U, TsltU/U, 7x2teJ/M, ltxUxl/lt, and 12x14x1/1*. h stock for hm> - • Orders lor cpocUl alaao received In the -~ J -~ , . _„ _ — morning, at the sun* dojr. Binding posts, dials, and knobs to match. We have a of Coffla, Variometers, Vartoeouplars, Soekata and Rhea Largest Discounts. Jobbers and Daalars! Writs for propo- sition and Free Sample! ALLIED RADIO COMPANY, INC Dept. D, 441 SEVENTH AVENUE, NEW YORK CITY, FKxroy X7M WANTED— A Reliable New Entland Rspraaantativo. CAREFUL ATTENTION GIVEN TO ALL RADIO ENTHUSIASTS For CORRECT RADIO MAILING LISTS Use THE POCKET LIST We bm ham apanttaajtUT oarafal t* om ts It that no aTaaufaamw.. a dLaaanoaraoH. — ~ - ■ad IMa Is BM end. una lltt Bar » fatal Ms net otto an earn. or. or lit.** pot nar UMt is- aad ap te date at aD these). Fr\ Dirrskr17r«TQ >*■> carrinoton street e U. riWVjCllllJ, JANESVU-LE, WISCONSIN the fbopbk ____ _ .. this Mad sad, as ■ rale, thus enroll «d an far tana Mas nana), •ad roi irmand tt te be the faqt aaat lOtatasan earobere at say pries. Omtir baas reutj for dntribenm 01111111111 ink. FUee It J* par aaotluY aajmaaaaBB) etaae aaat ' 1 Uadtal Band lot erdst vt*T "TUNING IN" TO THE RIGHT TUNE IS VERY SIMPLE WHEN YOUR CONNECTIONS SOLDERED WITH THE NEW "POST SOLDERING IRON ft (The boo with the ■easrUHy to cover instrument on the From your dealer, tt Actual Sine LIST UM requirement for deHcata work. The Attachee to any socket. Universal Jobber or write POST ELECTRIC COMPANY M EAST 4ZND STREET, Div. MS NEW YORK Complete Loud Speaker true musical instrument If you loDe real ma*ic you can not afford to buy a loud speaker until you have beard STIHOLA CO fl CERT, you can hear it at our ruk. Keep it ten day 4 and then, if you tuisfo you can return it and your money toill be returned imme- diately. Cabinet type, beautifully finished in either dark oak or mahogany as yon prefer, with bronzed throat. Complete with cord — no extras to bny — ready to hook ap in place of headset, at dealers or postpaid. (Sent Aen T*r\ C. O. D. if preferred.) JJ) ls£eOU L. H. DONNELL MFG. CO. Dept. B, P Ann Arbor, Mich. Answers to Readers What is the power of the Naval station, NAH, New Yorkf Does this station main- tain a C-W transmitter T Is this the only station operated by the United States Navy near New York r— David Lloyd Jones, Fall River, Mass. The power at the Naval Station at New York is 5 kilowatts. There is a 3-kilowatt radiotelephone transmitter in the station which can be used for straight C-W, inter- rupted C-W, and, also, for voice production. This station is operated at the remote con- trol station, New York, and is not the only United States Navy station near this city. There is a radio station at Sayville, L. I., and another at Amagansett, L. I., operated by the Navy but under the remote control sta- tion in New York City. The Navy also maintains four radio-compass stations at Sandy Hook, N. Y., Mantoloking, N. J., Amagansett, L. I., and Rockaway, N. Y. The last-named station is for compass work with the airplanes. * * * Will you please publish a diagram show- ing the method for using a butter for de- tecting the sensitive tyot on a crystal de- tector?— Radio World Reader. Diagram of simple method used hi the selec- tion of detector crystals, requested by "Radio World Reader." The same hook-up can be employed to assist in the adjustment of the sat. The accompanying schematic diagram shows the method of employing a buzzer with a tuning coil. * * * What is the relation between the length and height of an aerial? — Frank S. Smith, Omaha, Neb. For receiving it is not necessary to have the aerial at such an excessive height. About thirty feet will do very nicely. An aerial about 100 feet long is necessary for receiving broadcasting stations. • * * / have a set consisting of a single-slide tuner with a pair of 2200-ohm phones, 3- wire aerial 35 feet long and 45 feet high. My aerial runs straight with the telephone lines, the distance from them being about two inches. Will this interfere with my setf At times I have trouble hearing voice from the telephone lines. What can I do to hear distinctly and eliminate interference f — Radio Student. Answering your first query: Try and see if you can run your aerial in one stretch of about 100 feet. One wire aerial is far better than a number at a shorter distance. When erecting your aerial run it in such a manner that it will be at right angles to the telephone wires. If possible keep it clear from them as much as possible. The further you get away from telephone wires the better will be the results. Don't place your ground wire on the same ground as {Continued on following page) If you did not get copies of Radio World No. 1 to No. 26, send ui $3.00. Or we will send you this paper for one year, ($6.00 for 52 issues) and start it with oar first issue, which will be mailed yon as soon as possible after receipt of order. -Digitized by VjOOQEC ——

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RADIO WORLD 25 Bea I npMT. Win raceeee in I ■anert. Make b« niceeee ' Tnlned r. » I.800 TO » 6 OOO •aoeflreeiTiod.lwnftranirooqrjl i ytjcr aper. time, to ooaatrt repair, maintain and utl i "* eoorao, low coat, i Writ, for ***>d t Rawaeweed A», Oo'l'au'iT'lM. WCLCOMCI COSH IM AMD HIAR THI CORACO RADIO CONCERT Daily. • A. M. •> f P. M. lira Flaar. 110 W. died tL. Mat to Aweteraa Teeatre The Coram Bopar-Badlopbon* b tba latest and — aanat in radio. It baa no artatde lnetallationa eiptnee la aa etmple l II w cannot call. to apatato aa • pbaaaraph. writ* tor foil Information. THE CORACO COMPANY. INC. IM Wat 42ed Street New Vark FEDERAL $ SS-W. 2200 OHM PHONES 5 Wo an alajag oat mm* owet aad wIM nnW^oao la lata of to* or anJ4.ll nan. T. D. .«. IMO Vara OKy. Daad tatttteaei vHft order, lanedl- J.H.IC S. ODELL COMPANY flUtlliaH ItH m-m WEST 4ZND STREET NEW YORK CITY TV* NttUaat Sbort Warn Tnaar em the I OaJy $SJ0 A PP ob I lb. L. W. GOODMAN O REX EL HILL, PA. St. aimer, at Cat tan, wrltaa: "Mj aarieetty Flaw Work and CioM Tunod VARIOMEtERS tkat will tin roe Plttabarfb. ... eaeee Oltr and otbar etaHene. wha with oar Tiiliiataijla GUARANTEED TO DO THE WORK OR MONEY BACK Wo faralak Free, ffUaj Skotak TftaM Call Hiaat Wlta Daaalal Look KhI And Yaw Da* Bay Dlratt UZ Fifth Amu Now Yarh City Oslana, Inc. Waal to Know AH About Aerial*? Bond 15 enu for a eopy of RADIO WORLD. No. 2*. dated Oct. T. TTU» nunbor conulno an article on tba fn-etlon, •are. elae. and itjlo of atrial. It la InforaatlTa, prartlal, and dmple. It la brlaf and to tba point. It waa written by tt D. Waionar. a radio RADIO WORLD. I4M Broadway. Now York. N. Y. Answers to Readers (Continued from preceding page) that of the telephone ground. Seek a new ground, preferably an outside ground. With all this in view signals should respond, provided you have a good crystal detector. However, we advise you to read and digest the article entitled "Why the Open Antenna Is Best for the Radio Listener," by C D. Wagoner, in Radio World, Vol. II, No. 2, dated October 7. This is very important. » • • Why can't I hear the broadcasting with a one-slid* timing-coil 4 inches in diameter wound with approximately 260 turns of No. 28 wire, phone condenser, phones, detector of the crystal type, and a l-wire aerial 80 feet long. The lead-in is about 45 feet. What should the wave-length of this set bet — Milton Semken, Salt Lake City, Utah. It seems that your aerial is a bit short for good results. Another thing: the size of wire you are using is too small. Its resist- ance is too high. This wire does not operate efficiently in a tuning coil. Too many turns have a bad dead-end effect As your set stands the maximum wave should be about 3000 meters and the minimum about 200 meters. You will have poor results on the smaller waves. You should either make dead-end switches or employ a shorter coil for the 360-meter wave. * • • Will you publish a hook-up of a receiver that will respond to long waves having the use of regeneration? — Harold Yankton, De- troit, Mich. 'Ktrra\ loodCoil lood| Condenser; Co.1 RereneratjYe circuit amp toying tickler cafl and loading coil lor long warat, rwanaatad by Harold Yankton, Detroit, Mica. The accompanying schematic diagram shows the proper connections for receiving the longer wave-lengths in a receiver. All connections should be carefully inspected be- fore any attempt is made to listen in on the set. » o • / am enclosing diagram of circuit used in my receiver. 1 would like to see a hook- up whereby one stage of radio frequency is employed with such a circuit. Have tried several hook-ups and this one gives the best results. — Thomas E. Cecil, Erwin, Conn. In Radio World, Vol. II, No. 2, dated October 7, this circuit was fully described by Mr. C. White in his article "Construct- ing a Radio-Frequency Regenerator." aaa Can you show by diagram how the wiring is accomplished on the tuner in Radio World, \o. 26, dated September 23. page 13, Figure ST Show the number of turns and taps thereon. — .V. L. Proctor, Valdosta, Ga. This information can be had only from the Bureau of Standards. Washington. D. G. the designers of this particular receiver. A broadcasting map for 15c. That is. a complete broadcasting map appeared in RADIO WORLD, No. 8, dated May 20 Mailed on receipt of 15c. Radio World Company, 1493 Broadway. New York Gty. Ranlilai an ' ^ ^ ^ |t ^ B luSatwa UV-st*. UT-ltl. O I it C M*. O-MI. Detewom aad laajlH St. St. ant raetred say Tte^rwaared o*jk^»»^ weald aownt ta taaatva mw. wU fl*a from aaw anC We an aow la a Mate antee far praam wdha tery laalll A taaajaal arm oar rwaehUtty. He trial will aaa- N Cum H. Poroel Co, law. I Q WOT MMIRVILLR. MAC*. ft V-A-C-U-U-M-T-U-B-E-R-E-P-A-I-R-I-N-C GOING-«iid Going Fast Wa baa a% a taw art aad aa* an aakaj ML bat wafc mm km wa wa eatfea to M0 wJaawal ant wlwV FwwIawnYwwl awTwwoV VT I Dwtactar and jajMjir SKH at abate tabaa aaa tba aaaatai araw ra aad ■Ta. iwayaattaaty. HADIO BUILDER" PLANS FREE I LIBERtY RADIO Oa Now York r«aj $SjM waJwa) « Pknw Cialiaiin JH MM. B Fl-kto CaawEjaawEtMaVV Jw%%B MM* JaaTaraan Tnaii.rwiin. EUR MM Oka Fraawk Pkii EUR MJR Varil Cawnlar EUt Tww-SUda Taanaaj CaHa aUI Hnll Ofwtan riMtal PrtwMtty Seed tar OwiUli Uat >f law law J. J. KELLEHER 14 UNION SO. EAST NEW YORK CITY ■y. ••>• "MIRAD" '^aiity RewSo Pries*! Ri«kt" S Plata Variable rialmin fLM Marad Vartcaualera Ut mm Okaa DawUe Head ISM Oka Sen«te Head (Maney bad Marad S Plata I Mind 41 Plate Variable ( Marad Detector Unit.. Twa-Staa> i of Above M« OA? Miracle Radio Mfg. Co. DYTERURBAN BUM, DALLAS, TEXAS GITHENS TRUTONE RADIO HORN — LOUD SPEAKER Ffarat eat to aol oa tea day trial Retail Price SZ1-M IoclocUe Load S (Maker by'eEyernT* It Le ' eaaaJd try Tret. V TOO eea'l a — .. be refaaded It la odd a a retreat** B eat earned by year Ditlnbnl0r$ eed Dnlrn. write / AUTO PARTS MFG. CO. IMS Treeably Ave, Detroit. Mka. Digitized by VjQOg [C

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26 RADIO WORLD DRIVE 100 TACKS AND SAVE $2940 M MM tm Be- lli lllsa; If.M. Tanrta, lltl. aad tt.U. Om- _ _ state Haas lists. IwOUOirauJ is. IS so. Spatial Wlaur aid* Curtalne that spas utm am 111.** op. Fart Baal Om 11.11 ■p. tard CuaUaaa H.T». All gsede turn m mt mtm, on. Quality tba beat and (uaranteed to flt. " i glean beat t» apply. - - - AUTO UUIPMINT 00.. 17 Oaaal Stnat Milium!. O. INSU-LITE PANELS 1/8 Size .01 per sq. in. 3/16 Size .015 per sq. in. 1/4 Size .02 per sq. in. DBALBRSi Writ* tor 41m General Merchandise Co. US Market Street Newark, N. J. Entirely does away with outside antenna and lightning arrester— all for $2.00. Sim- ply plug into any electric light socket— no current necessary — ANTENELLA IT SIMPLY HAS TO WORK AND IT WILL Awarded Um Emnlni Mall Certtleats at Eieelleeee At your dealer— otherwise aand us his nam* and UM and you will ba supplied without further charge. CHAS. FRESHMAN CO, Inc. Sole Manufacturers Daps. RW, m Hudson St.. Naw York CRYSTAL 5c. ca. 35c. w. 3 In. Bakelite Dtsls 100 — 13.50 100 — 321.00 right and left rotation 45c ea. CO! Ill E. Utth Nickeled or Brass ii.io a. IMIK Patta laamifesl mad Mdai. C COMPANY Naw York, N. Y. Big Eastman Pipe Organ Pleases Radio Listeners EXPERIMENTS in connection with the operation of the Eastman School radio broadcasting station WHAM, Rochester, N. Y., resulted in the broadcasting of one of the finest concerts ever heard. As radio enthusiasts have waited anxiously for the station to announce a schedule of music, experiments have been going ahead night and day in the hope that the auxiliary equipment would make possible the broad- casting of the excellent musical features of the Eastman Theatre. Walking into the sending station yester- day morning, Arthur Alexander, director of the Eastman Theatre Orchestra and a member of the Eastman School of Music faculty, who has had years of experience in radio activities, suggested the elimination of some of the auxiliary equipment used to relay the music from the theatre to the sending station. It was agreed that it would be wise to try and simplify the equipment. Mr. Alexander directed the activities of the radio staff, and the experiments proved suc- cessful. Those who were "listening in" were treated to a real surprise when the peal of the big Eastman pipe organ was heard dis- tinctly and with little or no distortion. This surprise was magnified a hundredfold, how- ever, when the strains of the fine orchestra were heard. Football by Radio An interpretation of this year's foot- ball rules and a general discussion of college athletics will be given from WGY, Schenectady, N. Y., on Thursday night, October 12, by Lieut. Elmer Q. Ohphant, director of physical education at Union College. Lieut. Oliphant is considered one of the greatest alhletes ever developed in an American university. He is the only graduate of Purdue Uni- versity, or West Point, to win four let- ters, making the varsity teams in base- ball, football, basketball, and track. He was All-American choice for half-back in 1915, 1916, and 1917. In 1915, he was All-American choice in basketball and as catcher in baseball. The address by Lieutenant Oliphant will be part of a "college night" program to be put on by the instrumental and glee clubs of Union College. The program will include the songs and cheers of many colleges and universities. Dr. A. R. Brubacher, presi- dent of the New York State College for Teachers, will also speak on "Tradition in College Education." Rain by Radio RAIN will come and go at your own will, in the future: says "The Gazette," Falls, New York. This possibility is another prediction for the field of radio. It was made by Marconi, the famous in- ventor, at his recent visit to America. Other radio engineers also have expressed the opinion that the control of rainfall by radio is possible. Just as a bolt of lightning and thunder are forerunners of a rainstorm, says Mar- coni, so might radio produce the same result. "We undoubtedly will accomplish this wonder some day," he says. "And then we will become the lords and masters of life on this planet. We will be able then to obtain any amount of power almost without effort. "All the work will be done by the sun. Man will merely press the button. "The developers of water power and of the radio transmission of electrical energy produced by water power will become ex- porters of electrical energy to less fortun- ately situated countries." Subscribe for Radio World, 06.00 a year, $3.00 six months, $1.50 three months. FEDERAL PHONES $5 RADIO DISTRIBUTING A AUTO SUPPLY CO. M Wat Mth St, Now York Oty NA-ALD SMALL SPACE V. T. SOCKET 1 far II.M. with aOlaUasr. TJi or ban at boras ar saowJac Iras, braasa wtaata Hiatal petted " earewa. gasbag slat. Prim af larse pradsatSas. Special proposition for dealers and jobbers. ALD EN-NAPIER CO. Dept. U B Radiate Your Home AMATEURS Buy yeur parte and sets where the deal- er, buy. W. an nanulacturara aad will Mil yen at wtMltsela srlaat. Our Ult PHaa Federal Phenea— 2200. .. 18 00 ll.SO 6.50 4.(1 1.30 I. II 1.20 .05 Therdenon Traneferaier 4.50 3.10 Redle Frequency Traaifenaer 3.00 2.25 IV'rtle for Free Catalogue No. 100, Perfection Radio Corp. of America 702 Broadway, Ne w York Guaranteed 2500 Ohm Head Set $4.75 Complete Attractive aiatttaurafa, SCOTT NOVELTY CO. 33 SPRINGFIELD AVENUE NEWARK, N. J. Di 52 W««ks for $&M CompUto Your Filo of RADIO WORLD CopUa of Radio W 1 gitized by CjOOgle

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RADIO WORLD 27 JUST OFF THE PRESS The most up-to-date Treatise on Radio Textbook on Radio By JAMES R. CAMERON Whose textbooks are used and indorsed by the U. S. Army, Navy, and Department of Public Instruction 350 Pages. Profusely Illustrated. Written so the amateur can understand it. At the same time — TEXTBOOK ON RADIO— is a standard textbook for the technical radio student. A TABLE OF CONTENTS Would take neu of tkia oatlre page to fir* aa Idas, of tke complete- a«w book— TEXTBOOK on RADIO. Wo «aoU jaat INDEX "A." Page "AM Battery r 264 A C Radiophone Circuit 125 Adjustable Filament Rheostat 47 Adjusting Receiving Sets 177 Adjusting Transmitting Sets 103 Aerial Protective Device 89 Aerial Construction 71 Aerial Outfit 88 Aerial Switch 75 Aerial Wire 73 Aerials 59 Aerials for Various Wavelengths 59 Aeriola Jr 185 Aeriola Sr. Receiving Set 185 Alternating Current 38 Alternator, The 44 American Radio Transmission Set 108 Ammeter Connections 66 Ampere 23 Apparatus for Reception of Electro-Magnetic Waves 169 Apparatus for Undamped Wave Transmis- sion 107 Armstrong Super Regenerative Circuit 231 Audio Frequencies 43 Audio Frequency Amplification 153 Order NOW and Be Sure of Tour Copy! Cloth Bound, $2.50 Flexo-Leatho, $3.00 This new TEXTBOOK on RADIO is the nexv big brother to Radio's three best sellers "Radio's Three Best Sellers!** HOW TO BUILD YOUR OWN RADIO SET, 25c RADIO DICTIONARY, 50c RADIO FOR BEGINNERS, $1.00 Bay Them From Your Dealer or Direct From TECHNICAL BOOK CO. 130 West 42nd Street, Dept. W, New York Digitize ^Google

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28 RADIO WORLD PATENT Your Radio Ideas. tell sr Write FREE ADVICE A 5 MANUFACTURE roa^SED FIFTH AVE Recommended by Dealer* lor Reliability ADIO STORES CORP. VARIABLE CONDENSERS — PLUGS — RESISTANCE UNITS. ETC If yaur dealer dMM't een-y. addrsee Dept. D, 222 Watt 34th Street. NOT V«t —Rocky Mountain Crystals— i BETTER THAN 8ALENA Tbe mot awaaltlTS mioersi restlnex know*. Cm alas be used with see «t aan iiuit sf asaplla- Mounted, JSc.i Unmounted, Xtc.1 Rocky Mountain Radio Products, Int. • CHURCH ST- NEW YORK. N. T Superior Radio Products All Parts, Receiving Bets Mn ud la Unite. C«lm Writ* for Proposition RADIO OUTFITTING CORP. Be Apparatus Ntw York, N. Y. Mfg. High Grade Radl. 4M East 14th St. ALADDIN ELECTRIC COMPANY, INC. COMPLETE RADIO SETS WRITE FOR PRICES. 71 WmI Broadway Now York CHy Law Storage Battery Constant voltage, large amperage. Will run two month* without recharging. Attractive Dealers' Discounts Write for Detailt WILLIAM LAW COMPANY A born and Sabin Street., Providence, R. I. RADIO MAILING LISTS 9270 BeUll Radio Dealers. United States per at. 17.50 1184 lUdle Manufacturers par Hat, 10.1* 1330 Radio Supply Jobban par Uat, 11.50 257 Radio manufacturers of com- plete aate per list. 4.00 260 Badlo Stations per Uat. 4.00 14000 Badlo Amateurs and Man- agers of Badlo Stations. . .per M. 7.10 Neatly typewritten and ready to send you an receipt of remittance covering the amount. TRADE CIRCII.AR ADDRESSING CO. 100 W ADAMS STREET CHICA60, ILL, nm htolO BUILD YOUR OWN Co.np.et* Mr. In. true I Ion book for tOe.onlr on radio rerepllou and how to moke tight classes ol f r» »t»l mid *Bfnnm tub* f\ /v rorclTfnr SOU. Wonderful Inform I I 1 1/* •Hon makes roa understand radio. A I II' Wltk BT#ry order wo send free oui UVU prise list of parts prepared finer, ally lor tke levera. %* I ■ d-* scribed. Him dlreet trosi faetory and save tnanr dollars. Roth la- it met Ion book and price list gent on receipt of CO*, onli, Money back If not pleased. RADIO PARTS MFC,. CO. Dept. ,5, Partt P.. W., D.tr,.t M.sk. RADIO CITIZENS WE SAVE YOU MONEY Send us a list of your radio needs for our prices. If It's Radio, we have it and we sell it for less. JOJ^ Cr ' OCH COMPANY WEST VIRGINIA RADIO WORLD TELEPHONE. BRYANT 4706 PUBLISHED EVERY WEDNESDAY (Dated SATURDAY OF SAME WEEK) FROM PUBLICATION OFFICE, 1493 BROADWAY, NEW YORK, N. T. BY IULNNB88Y RADIO PUBLICATIONS CORPORATION ROLAND BUR Kit 11ENNLSS' . at. B. HKNNxiSSY. Vlce-FreaUlenl sKKU S. CLARK. Secretary ROLAND BURKE UKNNESSY. Edllor. 1492 Broadway, New York. FRED 8. CLARK. Manager. 14»1 Broadway, New York ASSOCIATE EDlTORSl Fred. Clue. Ehlert SUBSCRIPTION RATESi Fifteen cents a copy. 10.00 a year. 13.00 far SU moot ha. tl.50 for three Add fl.00 a year extra for and foreign countries. Receipt by new subscribers of the drat eopy at BADlO WOULD mailed to tbem after sending Is their order, la automatic acknowledgment of Uu*r auuscrlpuea aausji. at II we act of IS. 1021. at Naw York. New Yert. under i. 1*79. IMPORTANT NOTlCEl While every poaatble care U taken to ststs correctly matters of tact and opinion In technical and gaoetal writings covering the radio Held, aad every line printed la gone over with a acrupuleua regard for tne facta, toe publisher dlaslalm* any responsibility for atatemenu ragardbig questions of patents, priority of claims, the proper working out of technical problems, or other sutlers that may be printed In good faith and an Information furnlahed by those supposed to be trustworthy. This ststement la made In good faith sad to save SCR-79-A, Radiotelegraph Set Heard 2,700 Miles JN testing out the radius of one of its standard radiotelegraph sets, desig- nated as SCR-79-A, the United States Signal Corps has established a new rec- ord of transmission between 1,175 and 2,700 miles. A 79 set was temporarily installed in the headquarters of the 9th Corps Area, San Francisco, with the call WYCH, and communication was undertaken with Army transports on the Pacific. On one occasion, the "Sherman" reported having heard the signals from WYCH while she was 700 miles west of Honolulu — a dis- tance of, approximately, 2,700 miles. Other signals were exchanged between the Signal Corps station and the "Buford" over a distance of 1,550 miles, and with the "Sherman" again when she was 1,486 miles away. This record is considered very remark- able for a set designed for under 100 miles, although communication was not maintained for any length of time and interference was at a minimum. A Motorcycle Recharges Battery LONG spin on his motorcycle is necessary for Stanley E. Schnabel, Allentown, Pennsylvania, every time he wants to listen-in on his radio set. In a recent letter to WGY, Schenectady, New York, Mr. Schnabel, who is the Associated Press ^ operator for the "Chronicle and News," says that he uses his motor- cycle battery to furnish current for his wireless outfit and the battery generally lasts one evening. He recharges on his trip to and from work, but this isn't suffi- cient for the night's fun at the radio re- ceiver, so he takes a long spin after sup- per to get enough "juice" for the set. He is now planning to take his set along with him in his side car, put up a tem- porary aerial and ground, and listen in. In this way he can start up the motor- cycle every time the batter STANDARD HEADSET S.500 OHM ttw%s?3te.jr~ $5.75 Dealer, and jobbert write. Standard Electric Sales Co. Newark, N. J. Broad Street The "COPPER GIANT" Battery IS GUARANTEED FOR TWO YEARS In ANT receiving sat. because It dees net deterio- rate while stsndlng Idle This Is s Tory large battery designed for stationary or semi - portable Installations where absolute reliability orer s per- iod of rears la the first conatdersllsn. Standard voltages— 22. 00 and 100. Any railage made te order, writs far Illustrations, J. A. RITTER, Lansdowne, Pa. Agents T AROE MANUFACTURER OT SHIRTS wants Agents Is seU complete Una of shirts direst te wearer. Exclusive patterns Big values. No capita! or experience required. Write for free samples. MADISON SHIRT MILLS 507 Broadway Naw York. N. T. $4 CRYSTAL SET "THE LITTLE WONDER" tt.so UNMOUNTED Wonder in name and a wonder in per- formance. Cannot be equalled for the price. Catches distinctly everything with- in 25 miles. Send for FREE catalog, describing our "Little Wonder" set and listing radio sup- plies. Radi-O-Plare Panels. All sixes cut to order. HOLLOWAY ELECTRIC SUPPLY CO. ZM Third Avenue New York City Radio Supplies Variocouplera, Variometer*. Headsets, Transformers, Sockets, Rheostats, Etc 'ESS? Crystal Set $A Or Money Refunded PRICE. "X Send fifty cents for 20 efficient blue-print hook-ups. Any Radio Set Made to Order or Repaired Sunbeam Electric Co. 71 THIRD AVE. NEW YORK

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RADIO WORLD 29 Come to California Must sacrifice established WHOLESALE RADIO busi- ness. Controls exclusive sales agencies. Write Mr. Clay, 920 Chapman Bldg., Los Angeles, Cal. To the Man with an I offer a comprehensive, experi- enced, efficient service for his prompt, legal protection, and the development of his proposition. Send sketch or model and descrip- tion, for advice as to cost, search through prior United States patents, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently _ enable me to accurately advise clients as to probable patentability before they go to any expense. Booklet of valuable Information, and form for properly iBwlcwIns your Idea, free on RICHARD B.OWEN,p»t»nt Lawyw 32 Owen Building. Washington D. C. - p Woolworth Bldg Otherwise, Nothing Happened! EDITOR RADIO WORLD: Being a "bug" interested in your "ideal" magazine, I take the liberty to forward you this "Hash Comic Story." I met my girl the other "nite," and as I was walk- ing down to "receiver," her face "sparkled" with the "air" of joy, but I missed my "balance" and hit the "ground" and "2nd step." 'Twas some fall to "meter." As I fell, I heard the "crystal" of my "watch" break as I "tapped" it on the "dial." While I felt my "aerial" for bumps, who did "I-C" wandering down the avenue, a motor- car "buzzing" behind him, but "Cur- Rent" the villian. It was he who put the "damper" on my "radiation" with his sister Miss "Galena." As he passed I "gapped" as to not "c q" was passing, my lady friend was telling me how "delightful" she was over the "vacuum" sweeper I gave her for her birthday. Arriving at her home, her dad asked me to listen in on new set he had "re- senf'ly bought for "73" smackers. I did and was overjoyed. Just then the clock "registered" three o'clock "am (p) here." It was the "sig- nal" for me to "sign off" for the "nite." As "I-C"-was "going out" I realized that Mr. "Cur-Rent" was awaiting me with an "insulated" piece of "lead" in his "fist." I "howled" like a "squeak box" and the "copper" on his "feed-back cir- cuit" asked me, "How do you come over." He did not know my "location." The cop said he would "charge" me with vagrancy. I told him I'd put the "Ohm ^ Law" on him. He let me "pickup" my hat and told me to go "straight" home. So I took his advice and "dashed" "ohm" to my mother. — Doug Tremper, Brooklyn, N. Y. Radio World: 1 year (52 number*), $*■ ABC Standardized Radio Sectional Receiving Units and Radio Part, give unqualified satisfaction at low cast. Write for catalog. Jewett Manufacturing Corp. Mi Madison Ave, Dept G, Now York AGENTS Wanted tn every city and town to Mil radio apparatus. Good commiaaions. A few stocking agencies open to reliable parties. DELANCKY, PELCH A COMPANY U Meeting St. Paw tucket. Rhode Island Put Them in Your Phones Pictures and Facts About Armstrong Amplifier Radio World has published a number of pictures, diagrams and descriptive ar- ticles regarding the New Armstrong Sup- er-Regenerative Amplifier. The numbers containing this material are dated June 24, July 8, July It, August S and Sep- tember 16. They will be sent postpaid on receipt of 16 cents each, the fire cop- ies complete for 75 cents. Or yon oan subscribe, $(.00 year; ts.00, six montha and have your subscription start with the number dated June 14. RADIO WORLD CO., 1493 Broadway, Hew York. 22 to 500 Volt "B" Batteries Lasts Five Years Recharged From Any Lamp Socket The Sidbenel is a Storage "B" Battery that will last Ave years of constant use without replacing parts. It will give continuous service for at least six months before it becomes necessary for recharging. It can then be recharged in a few hours to its original capacity, all ready for another six months use. A Sidbenel Storage "B" is something every radioist needs. Think of the money saved by not using dry "B" batteries, which are of no use after they once become discharged. The Sidbenel pays for itself in six months. It is so ruggedly constructed that rough usage will not harm it. The container is one which is of genuine hard rubber, molded into ten compartments. Size 2V4" by 3" by 4%". Every inch of Sidbenel "B" is constructed under our own patents. The plates are especially treated with a newly discovered chemical that eliminates howling and screach- ing, so commonly found in any other "B" battery. The Sidbenel "B" is shipped to you partly assembled— all you need to do is connect the plates together, and this takes but ten minutes and is most simple, as instructions are furnished with each battery. Guarantee: — A two-year written guarantee is given with each Sidbenel Storage "B" Battery. This is your complete protection. For recharging we furnish a rectifyer for AC which costs 90.25 extra. DC current requires none. Complete with directions: One Unit, 2S volts IS.85 Two Units, 44 volts $7.50 Five Units, 115 volts $17.50 Eleven Unita, 250 volts $36.50 Twenty -two Units, 500 volts $65.00 Send for free catalogue on parts, and complete sets, and prices for repairing vacuum tubes. SIDBENEL RADIO EQUIPMENT MFG. CO. Dept. "B," 1663 JEROME AVENUE, NEW YORK,rj^it£ed byGo6gL

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS 7 TRY THIS DEPARTMENT AT So A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS MLD vfl buss) that ttan to ml tl wffl —fees ha RADIO WORLD oa the AD. DEPT. Is Sc. par — I In) Oum snore- ay, N. Y. €. fl HOOKUPS i Over 100 blueprints to from at 10c each. Send dollar for trial order. Radio Supply Co., Box 192. Pueblo, Colo. TO THE TRADE— Fixed Phone and Grid Con- densen. Write for price Hit and sample. SALKEY RADIO CO., 2378 Eighth Ave., New York City. PATENTS— Electrical case* a specialty. Pre- war charges. B. P. Fishburne, Registered Patent Lawyer, 386 McGiU Bldg., Washington, D. C Manufacturers of Rogers Radio Receivers and Rogers Receiving Radtosnetsrs. Rogers Radio Company, 5133 Woodworth Street, Pittsburgh, Pa. FREE with each $15.00 Western Electric Head- set, one UV 300 Detector tube. We handle every- thing in Radio. NEWBURGH RADIO SHOP, 236 Broadway, Newburgh, New York. Are you familiar with all the radio symbols nsed in the various hook-ups published in Radio World? If not, secure a copy of Radio World No. 26, dated Sept. 23. In this issue was a com- plete table of all important symbols used in radio construction and testing. Send 15 cents for a eopy, or $6.00 per year, and have subscription start with that issue. RADIO WORLD, 1493 Broadway, New York City, N. Y. SAVE S TO H% ON ALL SUPPLIES. WE •ELL SUPPLIES ONLY. LARGEST STOCK. $L50 Round Telephone Plug, 79c.; Flat, 60c 16.00 Arrow Variometer, $3.90. Moulded black Variometer, $4.75. Six Dollar Manhattan Tele- phones, $4.40- Best Quality V. Condensers with Dial, $2.35. MONEY BACK Guarantee. Include AMALGAMATED RADIO SUPPLY COMPANY, BOA WILLIAM STREET, NEW YORK CITY PATENTS Protect your Invention today. Write for 1922 Illustrated Book Free. Radio, Electrical. Chemi- cal and Mechanical experts. Over 30 years' ex- perience. A. M. Wilson. Inc. (Radio 3 ARH), 310- 18 Victor Building, Washington, D. C (Successors to business established 1891 by A. M. Wilson.) THE LOOP'S THE THING. The coming aerial, most simple and inexpensive of all when our blue prints and specifications of the two better types sre followed. Sent postpaid for $1.00. No stamps. McGehee Development Co., Box 1337, El Paso Texas. CASH FOR OLD GOLD. Platinum, Silver. Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps. False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash sent, return mail. Goods returned in ten days if you're not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Obi*. FREEi Galena Crystal and Bulletin on Radio Supplies. Postage— 2c. CONRAD RADIO COM- PANY, 76 Boylston Street, Jamaica Plain 30, Mass. NEWS AND GOSSIP OF THE STAGE— Send 10c. for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.00 year, $2.00 six months. $1.00 three months. New York Star Co., 1493 Broadway, N. Y. BROADCASTING STATIONS: Letters and ad- dresses of broadcasting station to-date appeared in Radio World for Oct. 7. Sent on receipt of 15c Also a broadcasting map appeared in Radio World No 8. Sent on receipt of 15c Radio World, 1493 Broadway, N. Y. City, N. Y. /ORLD. FOR SALE— Regenerative sets with detector. Complete with tube and B Battery, $35.00. With one stage, $50.00. complete with tubes and bat- teries. Satisfaction guaranteed. Edward Bittner, Schuyler, Nebraska. Exchange folly Inter— ting letters through our Club! Stamp appreciated. Betty Lee, Inc. 425 Broadway, New York City. ISSUES OF RADIO WORLD from April 1 to Oct. 7 (27 numbers) for 15c a copy, or the whole lot for $3.15. Or send us $6.00 for one rear and start with the first number. RADIO WC 1493 Broadway, New York. DO YOU USE A CRYSTAL DETECTOR T ARE YOU MAKING A CRYSTAL RECEIVER T Increase the efficiency of your crystal detector 1,000 per cent by using a "PT" Ultra-Sensitive Contact. Of special gauge and alloy. Makes and holds a quick, ultra-sensitive, stable ad- justment. Using galena, you may pound Panel or table without disturbing sensitivity in slight- est. Proved practical on shipboard by an old- time Marconi operator. Using a "PT" Contact on galena, Arlington (NAA) was brought in clear at 3,300 miles (below the Equator): and Arlington came in loud at 2,200 miles (off Dutch Guisna). In both Instances, nearby shine ■etna- vacuum tubes were unable even to bear NAA. As to stability. Cape May (WCY) was worked over 1,000 miles, sanding right through erjeeaJ with 2 KW spark, without affecting detector's adjustment. Replace your old insensitive un- stable contact with one which will hold its ad- justment in addition to giving louder signals and music Indispensable for pocket sets and crystal detector-bulb amplifier outfits. A novice can install. "PT" Ultra-Sensitive De- tector Contact, with instructions, twenty-ive cats coin or ICO. "PT" CRYSTAL CONTACT CO., Box 1641. Boston 8, Massachusetts. Navy Radio Sets Bring Bid of $206 THE opening of bids by the United States Navy revealed the fact that forty-seven firms and individuals were interested in the 395 radio sets offered for sale recently. The highest bid re- ceived was on September 28. It was $206 per set, but the awards were not made until late in the week. STATraoMT or not owncrbhip. management. CIRCULATION. WTC. KBQTTTRgD BT THB ACT OF CONGRESS Or AUGUST 14. 1912. Of Badle Werld. published weekly at New Tart. N. T.. for Out. 1. till. BUte of New Turk, County of New Tort, as.: Before ma. a Notary Publls. in and for the S-ete sad Count? aforesaid, personally appeared Boland Burke Hon. neear. who. hiring been duly awern sotordlngto law, de- poses and ears that he Is the Editor of the Radio World, and that the following la. to the beat of his knowledge snd belief, s true statement of the owoorsh'p. management (sad If s dally paper, the alreulatlee). etc.. of the aforesaid publication for the date shown la the shore caption. te- Any single copy of Radio World, be- ginning with No. 1, mailed on receipt of 15 cents postpaid. Any seven issues for (l.M. Or send $3.00 for 0 months' (20 num- bers)) or $6.00 for 1 year (52 numbers) and have your subscription start from No. 1. Radio World, 1403 Broadway, New York. quired by the Act of August 14. 1*12. embodied In I uon 443. Postal Lews and Regulations, printed on the lerarse of this form, to wit : 1. That the names snd sddresoos of the publisher, edi- tor, managing editor, and business managers are: Pub- lisher. Bonnesn Radio PubUcatJees Corporation. 1411 Broadway, N. Y. C. : editor, Roland Burke Henneaey, 14)1 Broadway. N. T. C : managing editor. Robert afackay. 1498 Broadway, N. T. C : business manager. rrsdK Clark. 1498 Broadway. M. T. C 2. That the owners are: (Dire names and addresses of Infflrldusl owners, or. If a corporation, aire its name sal the names and addressee of stockholders owning or be'dlng 1 per cant or more of the total amount of stoek): Hen- nesay Radio Publication Corp., 14)8 Broadway, N. T. C. ; Roland Burke Bsnnsssy, 149* Broadway. N Y. C. ; It 1. McArthur. Statler Hotel. Cleveland. Ohio. s. That the known bondholders, mortgagees, snd ether security holders owning or holding 1 per sent or mere of YOUR PHOTO IN THIS PAPER ATTBflTIOfl AMATEURS! Have you built your own receiver? Are you experimenting with any par- ticular hook-up? Are you improving your set? Are you doing any interesting construc- tive work in radio? Why not ihara tMt knowledge with your thousands of brother font who read RADIO WORLD every toeefcf We want pictures of receiving sets with descriptions of how you overcame some ■difficulty, or of any additional part or unit that you have added to obtain better results. These are the things that, prob- ably, the other fellow is looking for. Send in your information; pictures or what- ever you have done to improve the art. Remember them. the beginner is looking for We intend to print in this paper, each week, pictured information and descrip- tion of value to radio amateurs. If you have found a newer or better way of doing anything, don't keep the secret but tell it to your thousands of brother fans. Send in s photograph of your set with or without accompanying diagrams and measurement. State whether you figure in the picture yourself, or not, and with- out any expense whatsoever to you we will make an engraving and publish it. B.e.,,ure to write *onT °«rae and address plainly on photograph. Send in your picture at once, or if you have not made a set or done anything else in making radio material, tell the boy next door all about this offer. RADIO v Address Technical Editor O. 1493 Broadway, New York City, N. Y. total I amount of bonds, mortgages, or other eeourtUes sre: (If there are none, so state. I Nona. 4. That the two paragraphs net •bom, tiring the names at the camera, stockholders, and eeeurlty ha" If any. contain not only the list of staeknot.lers sad L Ity holders as they appear on the boo- a of the campeai but also. In eases where the stockholder er eoaurlty holder •Ptwors upon the hooka of the eompsay aa trustts er fa any other fiduciary relation, the name of the parson er corporation for whom such trustee Is earing, la si* an: asm ™' tbe said two para graphs aontaln statements erabrsalae affiant's full knowledge and belief as to the stnsuaa- staneaa and conditions under which stoek holders and secur- ity holders who do not appear on the books at the earn- pany as trustees, hold stock and securities in a sapeslty other than that of a bona tide owner; and this affiant ram no reason to boll ere that any other person, ssssilsllm. er corporation has any Interest turret er Indirect In ttssasja stack, bend, or ether seeurltlaa than as ss stated by sua That the swage number of carries at each Issue of this publication said er distributed, through the seal si ss otherwise, to paid subscribers during the all raeatka pia- eedlng the date shore ahown la worker. (This Information Is a^uaSr.Uim. •»D«rt«"1 before aw this lIuTdaT'ef KARL M. QOTTFRIBD Netuy PubHs. Now Tort County. NrwTerk " Clerk's Na 804 New Tort Register's Na 4128. mission expires March 80, 1924. Nets.— This statement mast be mads la duplicate aad both copies dsUrered by the publisher to tne^estasaatar! who shall aend one tm to the Third Assistant Pastmutar General (Dlrlsten of Classification), Washington, D. a", and rotate the ether In the files «/ the net eflW The publisher must publish a eopy of this statement In the second Issue printed neat after Its flues. Broadcasting Suffering in Germany BROADCASTING in Germany seems to be suffering from an overdose of "verboten," according to reports reaching the United States Department of Commerce from Vice-Consul Nathaniel B. Davis, at Berlin, says an International News Service dispatch from Washington. With apparatus costing a great deal of money, and with Government restrictions weighing heavily, the amateur does not enjoy anything like the freedom of activity that obtains in this country. The German Post Office Department, which is in charge of all radio communica- tion, permits private companies and indi- viduals to build their own plants only on payment of a license fee. Ordinarily, the department itself installs the plants; it also rents receiving sets for 2,500 marks a Digitized by

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RADIO WORLD Orange Label Tea Special lOt Tins So good, you ask for more! Enjoy a cup of good tea — let it greet you at breakfast, cheer you at luncheon, revive you at dinner and promote refreshing sleep. Also sold in / lb., '/2 lb. and %lb. TINS Sample will be tent on K.NW. St, New York. GOLD MEDAL San Francisco 1915 oRAND PRIZE SanDie&o 191t> Digitized by Google

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RADIO WORLD —and now harmony replaces discord! MUSIC— clear aa a bell; speech— so that every word is marvelously distinct; jazz— in un- interrupted syncopation; opera— with that transcending;, full-toned quality which brings its remarkable beauty into strong; relief. This sort of radio reception is a matter of batter- ies. Elimination of most noises is a matter of batteries, rather than static or other interference. These noises are caused by the irregular voltage output, natural in ordinary "B" batteries. Where the current output becomes unvarying;, these noises cease— and this marvelously clear and life-like re- ception results. And it is because RADIOBATS "A" and "B" are the only batteries which act as radio batteries should, that we urge you to listen to a demon- stration at your dealer's. Until you have actually heard reception through RADIOBATS "A" and "B" you cannot imagine how wonderful radio can be — and there is no way to hear it, till these epoch-making, new-principle batteries are hooked in. RADIOBATS "B" — as well as "A" — are leak- proof because they have the only solid elec- trolyte; and they are more economical, because, like "A" Batteries, they are indefinitely recharge- able at home. Send now for the intensely instructive booklet "The permanent Power Unit for Radio" and send your dealer's name and address so that we may arrange an immediate demonstration. There is absolutely no obligation. MULTIPLE STORAGE BATTERY CORPORATION 350-A Maditon Avenue, New York RADIOBATS J/ie iPermanentlladio l^ower-JJNll t« A '$ A and B Digitized by Google

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ILL (Trad* Mark) U S T R A TED TVBLISHEV EVE-RV S E V E // 2) A V S 250-Watt V-T's Broadcast Big News Events A PAGE OF HOO ee Page 12

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[E who knows .will tell you he Grebe CR-5 performs on\ the, daily concerts, lectures'etc., in the afrv Two simple tuning adjustments are used. Tiresome adjustments, unpleasant interruptions are Jim at t aasary with Its range, 150 — 3000 metres. Ten years experience in satisfying a critical radio public has taught us how to build it for your year- round enjoyment. If your Dealer does not sell Grebe Radio Appara- tus, send us his name and esting cir- Licensed under Armstrong U. S. Patent, No. 1113149 Digitized by Google

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VOLUME TWO RADIO WORLD [Entered as second-class matter, March 28, 1922, at the Poet Office at New York, N. Y., under the act of March 3, 1879.] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. Vol II, No. 4. Whole No. 30 October 21, 1922 15c per copy, $6.00 a year Editorial Announcement! RADIO WORLD Suggests National Radio Week Nov. 26 to Dec. 2, 1 922 REASONS: i To create greater public interest in radio. To increase the output of manufacturers. To increase sales by distributors and dealers. To make possible a still greater volume of Christmas-gift purchases. PLAN OF CAMPAIGN: Request interest and space of radio editors throughout the United States and Canada for a National Radio Week. Remind fans that Radio parties would be pleasant and profitable, and that during that week they should invite friends— especially those not acquainted with radio — so that they may listen in with their hosts. Bigger and better window and counter displays daring National Radio Week. Have you, as a manufacturer, distributor, or dealer, or fan, any other suggestion to make? Suggestions forwarded to Radio World on this important event will be received gladly and accorded attention in the editorial columns of Radio World. The suggestion now is that NATIONAL RADIO WEEK be held from November 26 to December 2. (Thanksgiving Day falls on November 30.) Why should not radio, bringing music, entertainment, end information, and supplementing the official Thanksgiving message* cheer from oar President and the Governors of States, be made an important part of the wholesome activities of ThanksgiV. hag Day? These greetings, coming from men of oar country prominent in science, literature, the stage, and the church, and heard through the new medium of radio, will give an added importance to their utterances. Write and tell u* tohat you tvilt do to help along Rational Radio Week Address at once: /fat tonal Radio Week. Editor, Radio World, 1493 Broadtv ay, JSTebv york Be a Booster for National Radio Week ! Digitized by Google

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RADIO WORLD Important Improvements in Radio Receivers By C. White, Associate A. 1. E. E. SO busily are we engaged in trying to invent new circuits that we often forget the pos- sible improvements we can make in the construction of the average radio-receiver. Fortunately there are many manufacturers who, real- izing that amateur radio popularity is here to stay, are actually employ- ing scientific research to better their apparatus. Still, nevertheless, there are a vast majority who are satis- fied to build anything that just works — and that's all. But, the amateur who builds his own outfit is subjected to the same dangers as the unscientific manufacturer, in that he is often deceived into think- ing that if the set works it is O. K. in every respect and represents the height of efficiency. There is not a man who would knowingly put a poorly constructed appliance in his home, but there are amateurs who care for nothing save to hear a sound over their sets, and they will quickly say, "Why worry" if something is at least heard. On the contrary, a majority of radio fans are electrically inclined and are beginning to seriously consider if they have outfits that present the acme of electrical perfection. The first consideration in any electrical circuit is to cut all losses as low as possible without incurring too much expense. The average dividing line is generally the point at which scientific perfection and economical construction costs are just about balanced. In other words, if a certain additional im- provement saves less than the cost to make the same then it is foolish to incorporate such an alteration. In most every radio circuit, variable condensers of the rotary plate, air insulated, type are employed. These condensers as generally constructed for radio work have a rather high loss of energy, owing to the fact that the air gap is relatively large. The amateur will find that, in the ordinary regenerative and non- regenerative circuit, it is far better to use a fixed mica condenser, shunted with a small three-plate air condenser as a vernier. By so doing, he will not only cut down the initial cost of installation, but will also raise the efficiency of his set, since a mica condenser is more nearly a perfect condenser. For most tuning circuits, a mica con-« denser of .0005 microfarads with a large three-plate vernier will be Have You a "Radio-Regulated" Watch? (C. Kadel & Herbert News Service) The up-to-date jeweler regulates the watches left In his charge by radio, because the time of the day sent from Washington, over the ether waves, la so absolutely correct there cannot be the slightest variation of even a fraction of a second. The en*- raving shows Simon Rimler, a New York jeweler, and hia radio time-receiver. Soon the boast of the man who knows thr.t his watch is exactly on the second will be: "Mine is a radio-regulated watch." about the right size. If .0005 mfd., is too much capacity another mica condenser of .00025 mfd., may be placed in series with it. The cost of such an arrangement is several dollars cheaper than a correspond- ing 23-plate variable condenser, yet it is more compact, sharper in tuning and, electrically, more efficient. It is even sometimes more economical to use the better scientific methods. The resistance of a radio circuit is often the least consideration. To the average man, any kind of copper wire is good enough. Generally he will employ No. 22 or No. 24 S. C. C, or D. C. C, magnet wire for his coils and No. 18 wire for hooking-up the component parts of the set. While there is nothing radically wrong with the use of the latter, still for the coils it would be far better to employ a wire made up of the smallest size of S. C. C. magnet wire procurable, wrapped together in the fashion of the strands of a rope. The number of strands will naturally depend on the size of one strand. By so doing, the effective resistance of the circuit to radio and audio-frequency waves will be greatly cut down. A single wire containing the same amount of copper will offer the same resis- tance to direct current ; but with respect to alternating current, its effective resistance will be much more owing to the tendency of high-frequency currents to crowd to the outer surface of the wire and not use the center. By using wires of smaller diameters in parallel and insulated from each other, this so- called skin effect can be reduced. The type of wire just described may be purchased at radio stores. Naturally, if the amateur so desires he can wind these strands if he has the time, but it is a slow and cum- bersome job without the aid of the proper mechanical appliance. Shielding is another point that has been seriously neglected on amateur apparatus — in many cases by the amateur building his own set ; in others, by manufacturers of cheap outfits. Any cabinet-mounted set should first be shielded from the body capacity of the operator. This is accomplished by lining the interior of the cabinet with fine copper-screening. Most people think that after this has been done Digitized by Google

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RADIO WORLD 5 Be Sure of Your Ground Connection THERE are few beginners who are dabbling in radio who realize sufficiently the prime im- portance of a good ground connec- tion. To many, the principal part of the receiving station is the aerial ; whereas, if the truth were known, the ground is every bit as vital to good clear and dependable reception as the aerial. Altogether too many amateurs spend hours in erecting an antenna, endeavoring to see that the wires do not touch other objects and inspecting joints to see that they are securely soldered. But the ground is left until the last and is then made by twisting a few turns of bare wire around the most con- venient pipe. The accompanying simple sketch explains the essen- tials of a radio receiving-station. By Fred Chas. Ehlert The radio waves as they pass through the air and the ground are oscillating in character. This means that they first go from the transmitting aerial to the receiving aerial, then to ground and from there back to ground of transmitter. After the cycle is completed, they reverse their direction and travel down through the earth of the transmitting set over to the ground connection of the receiver, up the antenna, and back through the other to the transmitting antenna. This scheme of going first one way and then the other is made possible because of the condenser effect. It is obvious that the ground must play its part as satisfactorily as the aerial. Whatever applies to the aerial applies likewise to the ground. (Continued from preceding page) the screening is one hundred per cent perfect. This is not the case, because we have only shielded our apparatus against external capacity effects and nothing at all has been done to cure the trouble originating from internal inductive inter- ferences. Each component part of the set should in addition have a copper screen around it. The ad- vantage of so doing cannot be fully appreciated in a small single-circuit receiver; but when the more com- plex circuits are used and the coils are mounted compactly, mutual in- ductive interference between coils is sure to occur and the only remedy is to shield each group of coils that are to be mutually coupled from the adjacent group. Care must be taken to see that none of the con- necting wires become grounded on the shield; and all shields should be grounded — that is, connected electrically to the ground terminal of the outfit. Another element that the ama- teur gives but little attention, is the selection of his vacuum tubes. The average man is of the general opinion that, for receiving, there are two types of tubes only: the UV 200 and UV 201. This is erroneous. There are other tubes for reception, although their char- acteristics are much different from those of the ordinary types. The power, or transmitting, tubes have proved very satisfactory in this connection. In fact, they give very much more volume per tube than the others. This is especially noticeable in the regenerative re- ceiver. The marked advantage of power tubes for reception is the in- crease in volume and the absence of hissing, such as the soft or gaseous tube is accustomed to do when operating at its critical point. The objection to the use of the power tube as a detector and amplifier is the necessity of securing high-plate voltage. Small-size B batteries in series is not an altogether satisfac- tory method of obtaining the necessary potential, since the cur- rent drain on the same is quite heavy. Manufacturers of B batteries are providing a larger size battery for this purpose. No matter what type of tube is used, it is always satisfactory to use some form of vernier rheostat for precise adjust- ment of the filament current. In choosing a circuit, always give 1 a double circuit first preference over a single circuit because the former is better in its selectivity. After you have chosen your circuit and are ready to construct, bear in mind certain facts concerning the general improvement such as I have explained. It may cost a little more to put all these improvements on your receiver; but you will find that they are fully worth the money, time, and trouble. When purchas- ing or placing an audio or radio- frequency amplifying transformer in your receiver, be sure to see that it is shielded, especially if more than one stage of amplification is used. Buy a good standard make of transformer, because trans- formers may "howl," even if shielded, if their coupling is too critical. For instance, the aerial is made up of copper wire of fairly good size. No. 14 will give good service. This is necessary to reduce the antenna resistance. Similar precautions should be taken with the ground. It should be made to present as low a resis- tance as facilities permit, so the minute radio currents may pass down the antenna through the set and thence to ground without being forced to overcome obstacles. It is safe to say that most grounds could be improved, but this is not always advisable because of the ex- H 1 1 i : i i > Receiving Set I I I 3 i i ! . 1 1 ! 1 ' i t I 1 i t i 4 I I I LJ SUirT Earth Currents tha df - Schematic diagram of tkm showing how tha nala or •ounde— pass from the aatanna and then back to tha earth. pense involved. A heating system may or may not make a good ground. The chances are against it; but if the receiving set is con- nected with the earth by a connec- tion on a radiator, the oscillating current must overcome the ohmic resistance at each pipe joint. If the ground connection is made to a gas pipe, the beginner may find that he has no ground at all. For the protection of their patrons, gas companies, as a rule, insert a wood or composition pipe-insulator somewhere between the gas meter and the first burner. If the amateur discovers one of these insulators, he should not overcome the diffi- culty by bridging the insulator with a piece of heavy wire, as he is t;hen nullifying the good work of the gas engineers. Instead, the ground wire should be carried beyond the meter before attaching to the pipe. Digitized by Google

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6 RADIO WORLD How Radio Was Installed in Our Home By Hattie Brtggs Hartman A FEW days ago, a motor-car stopped in front of our home. On the seat, by the driver, was a curious box. Before we were able to decide what it was, an elec- trician from a neighboring town jumped from the car, dashed up to the porch and announced that he had come to install a radio for us! In spite of our protests, he signaled his helper, and after asking us if we minded having a wire fastened to a tree at one end of the grounds, proceeded to install his magic ma- chine so quickly that it seemed easier to permit him to proceed than to try and curb his enthusiasm. A wire about the size used for telephones was fastened to a maple tree about thirty feet from the house ; the other end was fastened to the eaves on the second story. An insulator was arranged at each end of the wire, and another wire of the same size was dropped down over the edge of the porch. This wire was fastened to the machine. The men then began to look for the best way to use the ground wire, and decided that it would be feas- ible to bring the water pipe in the kitchen into play for that purpose. A small wire was run from the front porch, through the living room and dining room, over the tops of doors and wall molding, in- to the kitchen. There it was strung to the pipes which went up to the bath-room and so on down to the water pipe where it enters the kitchen from out-doors. The wire was no larger than medium-sized linen thread and was up so high that it did not interfere in any way with the occupancy of any of the rooms. The electrician rushed back to the porch, placed the jar of flowers which stood upon the porch-table aside very hastily, and put the radio machine on the table, under the hanging wire which came from the upper porch. This was fastened to the rear of the box, and the ground-wire was also adjusted. A battery stood upon the floor near the table and as the wires from the machine were snapped into place, to connect the battery, lights were visible inside the box which constituted the machine. The ma- chine was about 30 inches long and 14 x 14 inches the other way. At the lower right-hand corner there was a knob, which, when turned just right, brought sound to the proper Bulky Loose Coupler of 12 Years Ago and the Vario-Coupler of To-day (C. Eadel A Herbert News Serried Compactness U the watchword In radio as in all other up-to-date matters. Mr. F. Clinton (right) is holding one of the old, massive loose-couplers, popular twelve years ago. Mr. W. Cuillet (left) is showing, in comparison, the modern vario- coupler which has replaced It. The big Instrument is on the way to the seraph sap- degree of clearness. The expert adjusted the horn in its proper place, manipulated the knob, turned two small dials which were at the side of the box and, in a moment, cried, "We hav.e it!" He listened a second longer, jerked the head-set from his ears, and turned with a satisfied expres- sion as he looked at our bewildered faces. In the shortest space of time imaginable, a burst of music came to us from Washington, D. C, and we were listening to one of the most famous bands in the country. Our home is at least six hundred miles from Washington. It was the most entrancing music we had ever listened to and we all sat with taut nerves, wondering whether it was really true or if the "city man" were playing a trick on us. It was rather a shock to us when the announcer gave the name of the band. We knew we had been listening to real music and not to a reproduction on a phonograph disc. Our visitor manipulated the discs a few seconds, and exclaimed : "Here is something!" At once we were listening to an orchestra in Pittsburgh. At the end of an over- ture familiar to every music lover, we were ready for anything which might come to us; for we knew that it was coming to us through space — over vast stretches of coun- try. We called in the neighbors by telephone and, in a short time, the porch was filled with a wondering audience. At ten o'clock we set clocks and watches by radio. A few moments after that, we were listening to a college glee-club in Wisconsin. We caught Newark, New Jersey, and heard a famous tenor. Later we heard a Shakespearian recitation. It was an adventurous evening; sitting on our front porch and hear- ing voices from the air ! Sunday afternoon a sermon came to us from Rochester, New York. We heard it as plainly as if we had occupied a front pew in the church. We were rather awe-stricken to hear the earnest message from the lips of a man of God so many miles away from us. The choir was won- derful. That same evening we had a treat in listening to a lecture on the City of Albany. The bed-time stories sent out from the broad- casting stations might have easily come from the lips of a mother in her own home while coaxing her babies to sleep. Digitized by Google

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RADIO WORLD 7 One-Tube Regenerator Hook-up for Loud Sigs By Harold Day Schematic diagram of ■ set capable of receiving signals of great volume. It is known as a two-variometer regenerative-type receiver, and it will pick op short wave-lengths of the broadcasting stations, continuous waves, interrupted continuous waves, and also ilnnped waves. All of these may be received on this machine, owing to the feed-back in tie) plate circuit. Drawn by S. Newman. WHAT should I do to my set that will enable me to hear the broadcasting sta- tions with much more volume, or, as they say, louder signals? This question I am asked most every day. Here is the answer: There are many circuits which may be tried out, but most of us don't like to dabble with hook-ups with which we are not familiar. The above is a hook-up of a one- tube circuit which will surprise any operator who dabble* with it. There is nothing complex about it — it is a plain, simple hook-up. No trouble should be experienced with a good aerial and ground. The parts need- ed for this set may be purchased at most any radio shop. They con- sist of two variometers, one vario- coupler, one tube socket and detec- tor vacuum-tube, one vernier rheostat, two switch knobs and about a dozen contact points. The wiring diagram is clearly shown. Care must be exercised to see that the proper connections are made. In the illustration, six con- nections, or binding posts, will be seen at the left. They are two for the A, or storage, battery; two for the B battery of 22 volts, and two for the connection with the tele- phones. In connecting up the B battery, one must be careful that the plus side is connected to the plate side of the tube. If this con- nection is not correct, signals will not be heard. There are -two variometers, one in the grid circuit and the other in the plate circuit. The variometer in the plate circuit tends to tune in and feed back into the grid the added voltage of the plate circuit. The set then becomes what is called a regenerative set. As all regenerative sets generally are hard to tune, it will be noticed that this type receiver is very simple to op- erate. Due to the self-amplifying feature of the set, signals of satis- factory volume will be experienced. Another Radio Myth Exploded By C. D. Wagoner ANOTHER myth to be exploded. Many people have the idea that an antenna attracts -lighting, that it is dangerous to have it erected near the house. When their attention is called to, possibly, the electric-light wires crossing the street and coming into the house overhead, or the tele- phone wire running in a long span from a distant pole, the answer often is, that these wires are insulated, and hence lightning will not strike them! This would be laughable if it were not so often heard. Lightning, striking through thousands of feet of air, the best insulator there is, would not bother much about an eighth of an inch of rubber surrounding a wire. The fact is, that lightning is just as likely to strike the power wires as it is the antenna. Yet we do not often hear of accidents due to lightning com- ing into a house by the electric-light feed-power wires. Do not understand me to say that lightning will not strike the antenna, or the power wires either. If light- ning makes up its mind to strike in a given locality, it is going to strike, and it is as likely to hit the house or the wiring inside it as any other point. As a matter of fact, a well-installed antenna with correct grounding device — described later — actually helps to prevent the house from being struck, in that it "drains off" the charges. Digitized by Google

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8 RADIO WORLD Broadcasting Increases Five-Hundred Per cent in Past Year Stations Now in Every State — Additions up to Going to Press WASHINGTON, D. C— There were 546 broadcasting sta- tions in the country on Oc- tober 5 ; one or more in every State of the union. These stations supply radio enthusiasts with all the enter- tainment, news, governmental data on weather, agriculture, health and other subjects they may listen to all day and far into the night. But the total of 546 stations is literally too great, and the stations are not well distributed, according to Depart- ment of Commerce officials. Most of the broadcasters are located in the East and Southeast, where time schedules must be employed to avoid interference. The public would be better served, it is held, if there were fewer stations and they were more widely distributed or located in proportion to areas and population. Five hundred and thirty-five stations are broadcast- ing on 360 meters, the balance on 400 meters. Sifting of Station's Neexfod "What is needed now," one offi- cial explained, "is a sifting out of the lesser stations, which are not rendering satisfactory service and popular entertainment, so that the radio public may listen in to good music, authoritative statistics, and current news." The creation by the department of the Class-B license, granted to only the superstations, will guarantee high-class entertain- ment and excellent radio service, since those stations are granted au- thority to use a special wave length of 400 meters. There are eleven of these stations located in seven States, making good programs, without mechanical music and cheaper forms of entertainment, available in practically all the east- ern and some central States, where the fans listen in on 400 meters, watching local papers for the daily programs. The 535 stations operating on 360 meters will have to look to their programs, as public opinion will in- dicate which shall continue in serv- ice for any length of time. The operating expense is so high that, eventually, only the good ones with sound backing will remain. In September, 1921, the Depart- ment of Commerce licensed WBZ, WJZ, and KDPM, three Westing- house Electric stations, to broad- cast at Springfield, Massachusetts, By Carl H. Butman Newark, New Jersey, and Cleveland, Ohio. They are still active today. During the next two months, Oc- tober and November, the Detroit News, WWJ, and the Westing- house station at East Pittsburgh, KDKA, were licensed, and then, in December the fun began. Twenty- three stations were licensed, Janu- ary saw the addition of only eight, in February there were 24 new licenses issued; 77 in March; 76 in April ; and, in May, the peak of the radio curve was reached with 97. Since then the number of licenses issued has fallen off slowly each month as follows: June, 72; July, 76; August, 50. In September but 39 stations were granted licenses. This, a government radio inspector says, is due to the fact that the sat- uration point is reached. There are enough regular broadcasters. Many of the larger, mostly the older, sta- tions are seeking Class-B licenses, but not maay such licenses will be granted, due to the qualifications laid down and the program require- ments. Broadcasting Now in Every Stat* With the issuance of a license in Laramie, Wyoming, every State in the Union now has one more broad- casting stations. As has been the case since the industry got a fair start, California still leads, having to-day, 66 stations, Ohio, follows with 35, and New York is third hav- ing 30. There were eleven licenses issued during the past week, as follows : KFDA — Adler's Music Store, 5 watts, Baker, Oregon. WMAV — Alabama Polytechnic Inst., 750 watts, Auburn, Alabama. WRAU— Amarillo Daily News, 20 watts, Amarillo, Texas. WMAU— Louisiana State Fair Association, 50 watts, Shreveport, La. KFEC— Meier & Frank Co., 100 watts, Portland, Oregon. WMAT — Paramount Radio Corp., 400 watts, Duluth, Minn. WNAG— Rathert Radio & Elec. Co., 45 watts, Cresco, Iowa. WMAQ— The Fair Corporation a/id The Chicago Daily News, 1,500 watts, Chicago. KFBU— Bishop N. S. Thomas, 10 watts, Laramie, Wyoming. WMAR— Waterloo Electric Sup- ply Company, 50 watts, Waterloo, Iowa. WQAQ— West Texas Radio Co., 60 watts, Abilene, Texas. Few Broadcaster* Hare Quit Of the 558 broadcasting stations licensed, twenty-six only have fallen by the wayside, so to speak, and some of those were deleted from the department's active list be- cause of the amalgamations of two stations in the same district or the transfer of a station, in which cases the service did not stop. The broad- ' casting stations dropped or changed are as follows : KOQ — Modesto Evening News. KNR— The Beacon Light Co., Los Angeles. WGNC— Orpheum Radio Stores Co. WCAZ — Robert E. Compton, Quincy Whig Journal, Quincy, 111. WAAE— St. Louis Chamber of Commerce. KZI — Irving S. Cooper, Los An- geles. WGH— The Fair, Chicago. WFAK— Domestic Electric Co., Brentwood, Mo. WEAQ — Y. M. C. A., Berlin, N. H. KGC — Electric Lighting Supply Co., Hollywood, Calif. WAAT— Otto H. Taylor, Wi- chita, Kans. WGM — Georgia Ry. & Power Co., Atlanta, Ga. KSC— O. A. Hale & Co., San Jose, Calif. WOC— Karlowa Radio Co., Rock Island, Ills. KQL— Aron A.* Klugs, Los An- geles. KGB — Edwin L. Lordon, San Francisco. WGH — Montgomery Light & Power Co., Montgomery, Ala. WPD — Newspaper Printing Co., Pittsburgh. KFU— The Precision Shop, Grid- ley, Calif. WDW— Radio Construction & Electrical Co., Washington, D. C. KDYY— Rocky Mountain Radio Corpn., Denver, Colo. WAAB — Times-Picayune Pub. Co., New Orleans. WQB— C. D. Tuska Co., Hart- ford, Conn. WAAF— Union Stock Yards & Transit Co., Chicago. KOJ — University of Nevada. Digitized by - university of Google

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RADIO WORLD 9 Every Radio Set Has a Reliable Range IT seems that the first question the average person asks when purchasing his collection of radio equipment concerns the rela- tive range of such a set. The dealer eventually may answer this question by giving some attractive distance, or he may be more honest and tell his customer the limita- tions of the apparatus and the range that may be expected under varying conditions. The range of any set, no matter how good or how poor, cannot be guaranteed. An estimate is no more than a guess. Two sets, identical in every respect, may have a widely different range when set up in dif- ferent localities. You may have a set that gives very good results and you may move only a few blocks away and discover that your set is useless. This may be due to the fact that you were not able to erect as good an aerial in your new local - ity as in your old, or your ground may be not as good. Possibly there are high buildings about you that would cut off some of the waves. Under given conditions, you can shortly ascertain the working or reliable range of your set. You will find that there are some stations that you can hear with, practically, the same intensity under almost all conditions. This distance you may call your "reliable range" although it may seem considerably lower than the range advertised by irre- sponsible dealers and manufactur- ers. At times you may hear remark- able distances with satisfactory in- tensity, but these results cannot be depended on. Therefore, they must be classified under the variable range of your set. There are many things which de- termine the range. Among them are time of day, atmospheric con- ditions, local conditions, circum- jacent obstructions, topography, (Continued from preceding page) KYW— Westinghouse Electric & Manufacturing Co., Chicago. Amateurs Still Increasing The interest in radio has been demonstrated also by the applica- tions for amateur transmitting sta- tions, of which there were 16,467 on September 1, 1922. On June 30, 1921, there were but 10,809 ama- teurs authorized to send radio com- munications. Since that time, fif- teen months ago, 5,658 more have been added to the ranks using 200 meters wave-length. By John Kent and the nature of the aerial and ground. Reception of transmission can seldom be carried on over as great distances during the daytime as during the night. This is due, possibly, to the ionization of the air particles by the sun's days, causing a partial absorption of the waves. Buildings with steel frames also ab- sorb waves. Topography has a de- cided effect on radio. Waves travel much more readily over water than over land. Metal and mineral deposits sometimes causes absorption losses. The importance of a good aerial and ground cannot be overesti- mated, as this greatly affects the range of a set. You cannot expect to get the same result with an in- door loop as with one outdoors. To Study Radiotelegraph Signals (Kapriatad by Oaml Kaqaaat) wBumm umnamum wibw LIST IF UUEVUTmS Tt IE ISO ■ UN — ffll "EST*- ««"■» I «— -"««. """""" 'Public correspondence It any radio work, official or private, handled on commercial ware lengttta When an abbreviation la followed by a mark of interrogation, It refer*- to Dm question Indicated for that abbreviation. In order to pasa the government examination, an amateur or expert moat be familiar vita the signals adopted by the International Radiotelegraph ic Convention. Thie la an Important ijaeetlni covering a licenee of communication. Digitized by Google raa QUA Qbl QBC QKD «J»» qig Q8J. «JeU hlp or atatloa (or: with )l Shall 1 Inform that you are calling him I U calling mat Will you forward the radiogram! lata you received the general call I . Ftoaae call ma when you have Snlshed (or: at ....o'clock)! Ia public correspondence bring bandied I. . Shall I lncreaae my apark frequency! Shall 1 decrease my spark frequency! Shall I send on a wave length of meters I Iwtahtoaemmunliatahy national Sfcraal Cede. Thtoto My distance to My tree bearing to I am bound far I am bound from I belong to the My wavebnajibb) .... _ I bar* weeds to send. I — receiving watt I am reserving badly. Please a a a awn I am being Interfered with. Atmospherics are vary Strang, lncreaae power. Deere ass power. Send faster. I base nothing for yoa. I am ready. All right aaw. I am bnsy (or: I am busy with ). do not Interfere. Stand by. I win call yoa when I oq ailed. Tear tarn will be No. / Year signal* are weak. Tour signal* are strong. The tone Is bad. The spark la bad. Tear spacing Is bad. My lime Is Transmission will be la alternate order. Transmission will be In series of s messages. Transmission will be In scries of IS messages. Collect The last radiogram Is canceled. Please acknowledge. My true course Is dsgisoi. I am nol In communication with land. I am In communication with (tl ). Inform that I am calling him.. You are being called by I will forwent Ibe radiogram. General call lo all stations. Will call when I bare Snlshed. Public correspondence la Please do not Interfere. Increase your spark frequency. Decrease your spark frequency. Let us change to the wave length of meters. Send seek word twice. I hare dlMcally I receiving you. Bepeal the laat radiogram.

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10 RADIO WORLD The Radio Primer Weekly A B C of Radio for the Beginner, in which Elementary Facts and Principles Are Fully and Tersely Explained /'F radio waves use the ether of the air, why is the earth necessary? Electricity must have a positive and a negative pole before it can be made to travel from one point to an- other. Electric currents always travel from a positive pole to a negative pole. If a radio wave of only one pole — either positive 'or negative — were to be Showing the wave length measurement of a continuous wave. sent to the top of the antenna, there would be no corresponding negative pole to attract it. Therefore, to secure a movement of the waves, the earth must be used as the other pole. The sketch shows how the wave travels. Part of the wave is above the earth's crust, the corresponding half is be- neath it. * * * What is meant by the wave length? A radio wave is supposed to have the shape shown in the illustration. Hoops of the electrostatic component of an electric wave motion. The length of the wave is figured as being the distance from the top (crest) of one wave to the top of the next wave. * * * Now that we know what wave lengths are, what have they to do with the sending and receiving of messages? One may have his own idea ; but the best answer to this question is the re- cent transatlantic achievement of the Amateur Radio Relay League by which it was proved that a short wave can travel great distances. Wave length does not have a bearing on sending distance, but the latter is not directly dependent on it. The large stations, such as the transatlantic, use the longer wave-lengths because they By Lynn Brooks are least affected by atmospheric dis- turbances and because it would be more difficult and more expensive to generate the high frequencies of short waves while using high power. * * * Transmitting stations use a number of wires, while for receiving only one wire is used. Why is this? The problem at the sending station is to shoot out just as much electrical energy as can possibly be handled. The additional wires provide this capacity. At the receiving station it is not ad- visable to try and pick up a great amount of the transmitted energy. It is better to arrange an aerial in the most economical manner and then use the energy so as to get the most from it. The receiving station is also both- ered with receiving impulses of inter- ference either from other stations or from waves generated in the air by natural means. A multiwire aerial picks up more of both kinds of waves and makes it necessary to lose much of the signal energy in order to get rid of the interfering energy. * * * Why is it that radio signals do not continue traveling forever? If the earth were perfectly flat and without trees, houses, or w<res, and if the air did change its character by day and night, there is no reason why the waves should not continue indefi- nitely. But every tree is a miniature antenna which picks up some of the ethered energy, houses and wires afford an easy path into the earth, and the air is affected by the sun rays to such an extent that much of the initial energy of the waves is neutralized. * * * Then would a one-wire aerial be best for receiving purposes only? This depends on the location and general make-up of the station. If the amateur is located over fifty miles from a broadcasting station, he should not attempt to receive with anything less than an outdoor aerial consisting of one copper or phosphor bronze wire, one hundred or more feet in length. If he is within fifty miles and intends to install an outfit with one or more stages of amplification, then an indoor aerial may be considered. * * * _ Why is one-wire considered suffi- cient for a receiving station? For two reasons: wave length and static. Most amateurs are concerned D primarily in the broadcasts which are sent out, with a few exceptions, on 360-meter wave lengths. To receive these broadcasts most efficiently, the natural wave length of an aerial should not be over 360 meters. The second reason has to do with radio's greatest enemy — static. Therefore, the greater the number of wires making up the aerial, the greater the static charge on them. The greater the aerial the stronger the signals received, but not in the same proportion. For these rea- sons it is best to sacrifice some of the signal strength in order to reduce the intensity of static. * * * What is meant by the natural wave length of an aerial? Every aerial has a wave length which it should pick up without any tuning whatsoever. This is the natural, or fundamental, wave of the aerial in actual use. * * * // the frequency of these waves are inaudible, how are they reduced? After the detector has eliminated one- half of each wave, it has done all in its power — all that may be expected. The remainder of the action must be car- ried out by the telephone receivers. Every time an operator at the trans- mitting station presses the telegraph key, a series of little sparks jump a gap and travel to the antenna. To a listener it sounds as if the spark were a single one, but it is really made up of hundreds of little sparks that start without much power and gradually grow to their highest power then de- crease to zero again. If we had a pen that could move fast enough it would trace a series of curves. For it is the sparks that leave the gap and pass up the aerial wire and down to the ground connection. In general, the spark impulse can be considered as having the same form until it strike* the receiving antenna, passes down- through to the tuning coil, thence to- the detector. * * * What happens to this wave when it meets the detector? The detector refuses to pass the en- tire wave. It will, however, allow one- half to pass through. * * * Will these waves make sound in the- phones? No ; because they are still traveling- too frequently. They must be slowed down many more times before the little diaphragm in the phones will transmit their message to the ear. igitized by VjOO^ IC

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RADIO WORLD 11 The Theory of Radio Communication How Radio Waves Are Generated so We Are Able to Hear Them THE atmosphere is composed of atoms of oxygen, nitro- gen, helium and other gases suspended in what the average in- dividual terms "nothing, or a vac- uum." "Nothing," however, is known to radio engineers as ether. Ether can be given a wave motion similar to that which occurs in water. To transmit radio signals it is necessary, therefore, to first create waves in varying groups and of varying strength; second, to inter- cept them with apparatus capable of changing them to sound waves. To create the waves it is neces- sary to have two surfaces separated by a distance of from ten to several hundred feet and to create between them an electrical pressure which changes its direction — first toward one surface, then toward the other — hundreds of thousands of times every second. By Horace Beers It is the common practice to use the ground for one surface and pro- vide another surface by erecting a structure composed of one or more wires insulated from the earth and suspended many feet above it. Be- tween these, by means of suitable transmitting equipment, we create an electrical pressure of from one to twenty thousand volts, which ra- diates in all directions. These pressure waves are, how- ever, only part of a radio wave. From any wire in which the current is flowing electro-magnetic and pressure electro-static waves are radiated. The creation of these waves may be compared to the action of hurl- ing a rock into a pool of water. The amperes of current put into the antenna correspond to the size of the rock, while the volts of electrical pressure are equivalent to the force with which the rock is hurled. The larger the rock and the greater the force behind it, the bigger the splash and consequent waves. The more amperes of current flowing in the antenna circuit and the greater the pressure (volts) between an- tennae and the ground, the strong- er the waves radiated. These radio waves have similar characteristics to another class of waves — sound waves. When the note, C, is struck on a piano, the sound waves it pro- duces vibrate 256 times per second, and either a C tuning-fork, or wire, tuned to C— or in its immediate vi- cinity— will vibrate 256 times also. Then the two wires are said to be in resonance. The waves radiated by a radio transmitter always pro- duce a definite number every sec- ond. In order to hear a station, the receiving equipment must be put in resonance with the waves radiated by the transmitter. This operation is known as tuning. Smallest Two-Stage Amplifier and a Dry-Cell Set (C. Kami * Hsitart Nm rbotos) Tn Hv ami Astinct apparatus*) far radio UN an •ham in th« abe»s pi, [mm TWr worn cons tracts by William A. Bruno. Tha Rnt illustra- tfaa la that of a two- star* ampUflar which, Mr. Bruno claims, la tha of Ha typo. Duo to Ha small sba it la ahrtona how such a small > to aparato. Mr. Bruno, of tha Anwrican Institute huilt this smpUftar for tho purpos* of makmc U a Two vacuum tubas, two trsasiis ana tha rhoootnta an al oaafbaal In tha cabinet. Oaa control tabs* caro of both tubas. Natwtthocanamc Ha small alas U Is so won assigns" that it sMmmataa all ■_D amy Author important fsaturo of this ■amttflsr la that It siiminatss Digitized by Google

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12 RADIO WORLD Radio World's Page of Hook-ups Realising that tho most Interesting phaM of radio with til* average "fan- la the testing out of hook-ups. Radio World win publish, from time to time, a page of the moat interesting diagrams, aoma of which havs already appeared in Ha pace*. An editor fuldee his policy by the wishes of his readers, and the number of requests for back numbers conf ' ' diagrams indicates that there la an Insistent demand for them. To Tuner Amplifying Tube P jt Schematic diagram of a crystal receirer, showing the loose coupler in a circuit. Thie method of rmmling la termed indue tire coupling. It has Schematic diagram showing the ampUfier and detector with radio- frequency transformer. P is a pluf from the tuning- circuit, J-l the jack of the amplifier. Suggested by Harold S. Potter. Drawn by S. Ne ~~ .OS-.SMf circuit receiver. Suggested by Charles H. Plath. Drawn by S. Newman. Schematic diagram of rsgenerative receiver of the variometer type. In the above hook-up It Is assy to discern where the variometers ere placed m the grid and plate circuits, respectively. Sug- gested by George W. May. Drawn by S. Newman. Schematic diagram showing circuit employing radio-frequency. A is the loading coil. B, any standard radio-frequency transformer. C-D are varlocouplers. E is s variable grid leak from 1% to I volt bias. As many stages of radio-frequency and audio-frequency may be added as the builder cares to use. Suggested by Dr. ft, S. Kelly. Drawn by S. Ne Schematic diagram of a regenerative set, employing variometers as means of regeneration. Jacks are utilized in the stages, which enables the radio listener to use as many stages as he desires. The grid condenser shown in the circuit of the second stage may be left in or out. This is to be con- sidered by experimentation. Suggested by Fred. Chas. Ehlert. Drawn by S. Newman. Digitized by Google

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RADIO WORLD 13 E?2iof,\Radio Receiver Radio Apparatus that Hurls Mes- *TT* HE telephone receiver com- X x ception^stno^artliewSca'se" SagCS AcrOSS the AtlailtiC receiver. It consists essentially of a per- manent magnet, A, with pole pieces having a north and south pole. On these poles are wound coils consist- ing of many turns of fine wire, as shown in B. C is the case of the receiver which is made either of aluminum or bakelite. E indicates when a current is sent through the coil of the magnet which takes this position. F indicates when the current flows in the opposite direction, de- creasing the total strength and allowing the diaphragm to spring away from the pole. A D-C resistance of a receiver, as described, would be about 2200 ohms. Over 10,000 turns of fine wire are employed to make up the winding. The impedance to an alternating current, of course, will be greater, depending on the fre- quency of the current and the effec- tive resistance of the circuit. At 400 cycles, a certain receiver of this type had an impedance of 2900 ohms; at 800 cycles, an impedance of 3900 ohms; at 1000 cycles, an impedance of 4400 ohms. This is the type receiver used by most amateurs and radio operators, to-day, in radio reception, whether it be spark, undamped, or telephonic reception. Army Tank Directed by Radio ONE of the new Signal Corps radio sets designed for the whippet tank.* of the United States Army was tested ont last week, for the first time, at the annual field day of the Army Ordnance Association, Aberdeen, Maryland. The standard sets, designed for the master tanks of each group, include both tele- graph and telephone apparatus. Under direction of the commanding officer, in the rear, the radio tank executed intri- cate orders immediately, charging and attacking- enemy tanks directed solely from* back of the lines. Observers re- port a most satisfactory test. (Both photograph*, C Central Newt Photo Service) Tho hog* radio stations used for tronaaHoatir work ara mtefwstia« studios. Oh of these stations, tho Radio Central, loeatsd at SUeorbead. Lone Inland, Now York, miles oast of the metropolis, contains scans of the Tho actual opsratlon of this station takes nines in New York City. The operator loeatsd there sends tho dots and dashes over land wires to Hi ■ willed, frees which nines they era broadcast. In order that ■ ososgss of ouch a nature mv ho sent. It is IsmiiarWo that tho proper power and circuits bo employed. Tho Oluotmtion at tho tap shows tho switchboards which control tho power. The various snot ore and circuit breakers which appear on the front of the switch- board keep tho operator Informed in regard to the power being used and also the power being transmitted to tho aerial. Tho illustration below shews the transformer rack. Digitized by Google

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14 RADIO WORLD Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave- for the Busy Reader. THE management of the Hotel Belmont-Causarinas, Ber- muda, proposes the installation of radiotelephony for the reception of the United States broadcasts. In view of its ideal situation on one of the highest points of the islands, the Hotel Belmont is particularly adapted to the installation of radio apparatus. The stretch of several hundred feet be* tween the hotel proper and the Causarinas Annex provides an excellent span for an antenna. * * * The boys who attended after school Athletic Centre 62, New York City, received a pleasant surprise from their teachers. As school was dismissed, a large scoreboard was set up in the outer yard, and all the plays of the World Series were bulletined as fast as they were received by radio. About 1,000 boys watched the returns, and expressed delight at getting the scores and plays. The teachers felt that the plan was worth while, as it served to keep the boys out of the traffic-crowded streets where they would have gone for the results. * * * Formation of a broadcasting' company by the six principal manufacturers of radio equipment in Great Britain is announced by Frank Gill, chief engineer of the International Western Electric Company and president-elect of the British Institution of Electrical Engineers. The company will have a capital of $500,000. Present plans call for the erection of stations at London, Birmingham, Manchester, Newcastle, Cardiff, Glasgow, Plymouth and Aberdeen. * * * The authorities at Yale University announce that athletic events will be broadcast by radio. This means that anyone within a distance of fifty miles of New Haven, will be able to receive by radio, play-by-play, reports of all the university's athletic events. All that is necessary is a small Crystal radio- receiving outfit. * * * The Radio Corporation of America has purchased the White Oil Building at 64 to 68 Broad Street, New York City, which it now occupies as its headquarters. The White Oil Realty Company is the present owner of the property. The building is ten stories high and contains 43,000 square feet and is valued at close to $1,000,000. It is within two blocks of the principal cable and telegraph forwarding offices and is near the Postal Telegraph Company's headquarters. The name of the build- ing will probably be changed to "Radio House." * * * Southwest Texas is coming to the front in radio affairs, according to the various county fairs held recently. There have been more than a dozen county fairs so far where loud speaking radio apparatus carried music and world news to the rural residents for the first time from WJAE at San Antonio. Lord Louie Mountbatten, cousin of the Prince of Wales, is visiting New York City with his bride, who was Edwina Ashley, heiress to the great fortune of her uncle, Sir Ernest Cassel, Lord Mountbatten, before the war a Battenberg Prince, is a lieutenant in the British Navy and he told reporters that he intended to specialize in naval radio. * * * A proposal of marriage by radio is reported by "The Amer- ican, New York. John Smiley, a wealthy engineer, sent "Will you marry me?" by radio, across the Atlantic, to Miss Evelyn Greeley, moving-picture actress, who is touring Europe. How- Sv,er\,It. 18 reported. Miss Greeley will return soon to answer "Yes," in person. * * * Radio ha* played a real part in the "movies." Marshall Neilan uses it in his forthcoming picture, "Minnie." In this production, suggested by George Pattulo's story, "Her Man," radio is employed, not only as a means of carrying the voice, but also as a medium of conveying power through the air and rnadihi* ry SUnt automobile8' wind-machines, pumps, and other * * * The Hipiiodyoine, New York, radio enthusiasts were par- ticularly elated last week when Edward Demmler, master elec- trician of the playhouse, with a radio receiving set of his own development, was able to hear the attempts being made to relay a telephone message from San Francisco to London. WJZ, at Newark, has invited the Republican and Democratic candidates for Governor and United States Senator in New York and New Jersey to speak from this station. The follow- ing tentative schedule has been arranged: Governor, New York — Alfred E. Smith, Democrat, October 25; Governor Nathan L. Miller, Republican, November 1. Governor, New Jersey — Senator William N. Runyon, Republican, October 18; Judge George S. Silzer, Democrat, October 21. Senator, New York— Dr. Royal S. Copeland, Democrat, October 31; Senator William M. Calder, Republican, October 24. Senator, New Jersey— Senator Joseph E. Freylinghuysen, Republican, Octo- ber 20; Governor Edward I. Edwards, Democrat, October 28. « * * H. V. Carpenter, dean of the State College of Washington, school of engineering, claims that ordinary telephone wires •may be used instead of aerial antenna in radio reception without interruption of either service. Professor Carpenter claims that conversations over the ordinary telephone are not heard on the radio receiving set when telephone wires are used for antennae, nor are radio messages detected on the telephone, so there is no interference or interruption in the service of either. This is probably the biggest step yet taken in the popularizing of radio, for it eliminates the most difficult feature of the receiving station. * * * A radio-equipped flying boat broadcast news of the National Airplane Races, at Detroit, on October 9. Those who listened in on 507 meters received the first radio report of an aviation meet. A high-powered flying boat, christened the "Wilbur Wright" by Miss Katherine Wright, sister of the "fathers of flying," was equipped by the General Electric Company with a 50-watt radio transmitting set with a range of 100 miles. Reports from this aircraft were sent successfully on a wave length of 507 meters, a length that was not too great for even the small crystal sets to tune with. Soaring at a height of 3,000 feet, this flying boat observed the contestants in the various events and sent reports by radio on the progress of the races. Special receiving sets were placed about the flying field so_ that spectators were informed constantly regarding the position of the planes, even when they were out of sight. A novel use of radio broadcasting has been announced by AdVenture.'' In a series of radio talks, L. Patrick Greene, of the editorial staff, will read the answers to a number of ques- tions submitted by readers to the "Ask Adventure" experts, from WTZ, at Newark, twice a month. Nearly fifty experts having first-hand knowledge of the far corners of the earth ««• n an?wering readers by mail, but will now use radio. If listeners in' wish to know about Alaska, India, Borneo, Central Africa or any other country, they are invited to mai their questions to the editor. * * « New York Oty becomes the world's radio central station, and the United States gains great commercial advantage by arrangements concluded by the Radio Corporation of Amer- ica, which organization has placed under one head Amer- ican, British, German, French and Argentine radio plants, rep- resenting an invested capital of $170,000,000. Concluding stages of the negotiations in progress several months, have been arrived at by radio between Edward J. Nally, president of the American corporation, who is in Paris; David Sarnoff. vice- president in New York City; Captain Powhatan Page vice- president and general manager of the Pan-American Wirel-ss Telegraph and Telephone Company of Buenos Ayres, who Ca"?u ?,re. S1? wee,ks, ago in furtherance of the plan, and officials ot the British and German radio interests. * * * Chauncey Olcott, comedian, returned so seriously ill on board the "Orbita" of the Royal Mail Steam Packet Line that a radio message was. sent to his physician, Dr. John A. Stillwell. of 9 East Forty-ninth street New York, to meet the ship at the foot of Morton Street. The radio was sent from midocean. * * * A radio corporation, capitalized at 200,000^00 yen, approxi- mately $100400^00, soon will be established in Japan, if plans formulated by the Nippon Yusen Kaisha, the Osaka Shosen Kaisha, the Industrial Bank, Suzuki & Co., Takata & Co., Mitsui & Co., Okura & Co., Fujita & Co., Viscount Shibusawa and other Japanese financiers receive the support of the govern- ment and are brought to completion. The plans have been laid before Premier Kato and have received this personal sanc- tion. It is desired to form a company that will compare favorably with the Radio Corporation of America, the Marconi Company of Great Britain, and the Telegraph Company of b ranee. The new company will concern itself principally with improving communication between Japan and America Digitized by Google

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RADIO WORLD 15 Radio and the Woman Crystal D. Tector ONE of the most attractive numbers sent out by WBZ, Springfield, Massachusetts, is the church service conducted by the Reverend Mrs. Frank L. Briggs. Mrs. Briggs is an ordained minister and served her husband's church as a regular pastor during his absence in France. Her choir is as follows: Hazel Rogers, soprano ; Esther Carlson, soprano ; Helen Page, alto ; Dorris Armstrong, alto; Anna Carlson, accompanist. Truly, women and radio are doing their share to spread religion. * * * Another unusually interesting broadcast, in which a clever woman was the bright particular star, was the address of Miss Minnie Tracy, a prominent music teacher, who told of her work with the late Enrico Caruso. Miss Tracy was a personal friend of Caruso. Her address was replete with some wonderful reminiscences of the famous tenor. * * * A woman friend whose hobby is golf has become, also, an ardent radio fan — and all on account of a new golf ball with "a radio-active center." She tried to secure a brand of ball, she says, which she had used for years, and the radio ball she purchased because the dealer was out of her favorite kind. She says that this new ball, when hard hit, races yards farther than any other she has used. * * * The big alternator in the musical comedy, "Molly Darling," now playing at the Liberty Theatre, New York, really gave me a thrill. It was the first time that I had seen radio on the stage in a truly startling way. The management is wise in saying this piece of dramatic intensity until the last scene, for it is a very unusual climax to a snappy entertaining show. Miss Jessie E. Koewing, recently gave a very interesting talk on radio before the Men's Club, Belleville, Ohio. Miss Koewing, as most every radio fan knows, is the announcer at WOR, Newark, New Jersey and by the bye, one of the best announcers in the country. After the talk, Miss Koewing was accosted by one of the members who told her that his seventeen-year-old daughter had made a wonderful receiving set entirely by herself. I wish that I might meet and interview this girl. Miss Koewing, in the rush of the night, did not get her name, but I would consider it an honor, indeed, if she would write me and tell me all about it. * * * WJZ recently broadcast a joint recital by Effie Briggs, soprano; Vincenzo Alpino, tenor, and Hazel Gruppee, pianist and accom- panist. Miss Briggs began her musical career when only a child. Her dramatic ability, much in evidence in high-school entertain- ments, suggested that some day she would develop into a celebrated Shakespearean exponent. She attracted the attention of several Bostonians .who suggested that she prepare for a grand opera career. She has studied under Camille Bonsignora and other grand opera coaches. Miss Briggs is quite versatile, being able to sing in nine different languages. "Including radio?" asked Friend Husband when I told him of Miss Briggs's versatility. * * * They tell me at many of the New York department stores, that the most interested — and frequently, the most numerous — customers at the radio counters are the mothers whose young sons act as escort. Of course, it is the boys who actually want the sets, not the mothers! But it is mother who opens her purse to purchase the set, and, also, to ask innumerable questions in regard to the new magic. A well-informed radio clerk told me that several mothers told him that radio sets have tops and balls and other matters of boyish interest beat to a standstill as a suitable reward when John- nie has been extra good. * * * One of my correspondents — a lady who lives in Portland, Ore- gon— writes to ask if I can tell her what Major Edwin H. Arm- strong looks like. I saw the major when he demonstrated his superregenerative set at Columbia University. In fact, I stood very close to him. He is a very interesting personality. Unless you watch them very closely, his blue eyes do not flash. He has an open interesting face, an erect figure, rather prominent mouth, and is beginning to show traces of baldness. But what impressed me most was his modesty. I doubt if I ever met a more modest young man in all my life. Looking into his face, I would say that he becomes wonderfully animated when trying to solve some deep problem. * • * I have been asked by several women's radio clubs to speak before them this winter. Really this is impossible. In the first place, I am a poor speaker; in the second, I dislike traveling; in the third, I pre- fer to write what I have to say. I am always pleased to tell my sisters, through the courtesy of Radio World, anything they may want to know — and may I be so bold as to add that some of my pages in Radio World this fall and winter, will contain matter that may be read to advantage before any club. You will always find some practical informative paragraphs every week that will be worth saving and that, when put together, will comprise a better lecture than I could deliver from the platform. We women are not good talkers as a rule. Broadcast Bill's Radiolays (Copyright, 1922, Westlnghouse Electric A Manufacturing Co.) THEY say the village barber shop's the most convenient place to settle all the troubles that affect the human race. The one we've got in our town's no exception to the rule, so as a natural consequence, the shop is always full. Since Mister Barber first invented tools fer cuttin' hair, the way the government should run has been decided there. The last time I went down to get my curly locks cut short, I helped them settle questions that we thought of great im- port. But gosh 1 with nine ahead of me I had to wait so long I said right then the next time I'd amuse the waiting throng in manner more befitting, so to speak, an' up-to-date than tryin' by our talking to direct the affairs of state. An' while I like to keep our land from goin' to the dogs, I'd rather have 'em tell me what's the market price on hogs. So yes- terday, when I went in to get my weekl- shave, the barber shop executives had started in to rave about the possibility of war with China soon. I busted up the meetin' when I sez, "Let's have a tune." I'd brought my faithful radi'phone along with me this time to listen to while waitin' 'stead of talk of war and crime. With set an' horn connected up, the music came in grand, an' while we sat there waitin', Sousa's Military Band played four or five selections an' the time went by so fast that pretty soon I noticed I wuz "next" instead of last. We had some right nice music an' as I wuz gettin' shaved, they told us in the latest news how Wall Street had behaved. "Doc" Dalton runs this barber shop an' I've a dern good hunch, he's goin' to buy a radi-phone an* then surprise the bunch. He asked me all about my set, an' how much I had paid an' if I thought a set like mine would help bring in the trade. Well you know me— I sez, "Why sure, I'd get one right away. Just look at all the extras this here one brought in to- day." WJZ to Broadcast Foot- ball Games from Field WJZ, Newark, New Jersey, has, through the courtesy of the Western Union Telegraph Company, arranged to broad- cast the more important football games that will be played at the Polo Grounds this fall. The radio audience will not only learn every play the moment it is made, but will also be able to hear the cheering and the songs of the college men. The schedule is as follows: October 21 — Fordham University vs. Georgetown University, Polo Grounds. October 28 — Syracuse University vs. Penn- sylvania State College, Polo Grounds. No- vember A — Lafayette College vs. Washing- ton and Jefferson College, Polo Grounds. November 11 — Cornell University vs. Dart- mouth College, Polo Grounds. November 18 — Columbia University vs. Dartmouth College, Polo Grounds. November 25— Army and Navy, Philadelphia. November 30— University of Pittsburgh vs. Pennsyl- vania State College, Pittsburgh. igitized by G00gle

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The Most Up-to-Date Things of ti I I (Left) A. C. Brawn, who, forty yean ago, invented the street fire-alarm, has perfected a device which doc* away with the necessity of wires or even an aerial from the Are-box to the Are station. By means of Mr. Brown's apparatus a high-frequency cur- rent is conveyed alone the public electric-light mains and collected by a simple apparatus at the Are station, which in its turn sounds the alarm, switches on the Are-station lights, and, what is more, writes on the tap machine the exact place of the Are. The object is for the device to be fitted to ail hotels, theaters, and large premises. The call fat mails by pulling a lever in the usual way. (C. Ka outfit she though ch If it be m I (C Kadel & Herbert New* (C. Kadel & Herbert News Service) Digitized b

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RADIO WORLD 17 ie Past Week in Radio's Busy World W. Y.) •too outfit nil bt a valise. It will nm receive while you the nWif. And II you srs riding at the subway and you r male wbaa a chap alts down basUa yon, ana plants his r (sat. yen never caa tall what Is in the valise. Thbj radio cam ha carried hi a valiaa, and If sat to receive, even 1. h wfl catch whatever part of tha radio program la on. e, you'll hoar it. It Is a six-stags audio-frequency amplifier , a oeaaalsta sustained receiving apparatus, including loop ksrlaa and loud speahsr. It can bs opsratsd anywhars. rows* J. Klmm is shown with tha suitcase radio. (C. Kai.el & Herbert Newi Service) Tha accoaspanying Ohutratioa shows Rutlsdge R. Mayo, of tha United States Navy, with an Armstrong super-regenerative eet which he built himself. By assone of a sperlal type vario- coupler, constructed by himself and placed la a certain position in tha circuit, he success fully overcaaes the trouble that la betas encountered by aasstsurs— that Is noises and that whistle which Is ssssethnes discouraging. In this three-tube circuit Mr. Mayo usee no rheostats or potautiomitsn. 1. ropreeeats the Western Electric land epashsr; 2, tha high-voltage B batteries necessary far the pistes ml the tubes; J, the caatral or coo- denser dial; 4, the E tubas (Navy type) used throughout the circuits t, the varie couplsr. The loop aerial caa ha aeon to the left as the table. Mr. Mayo has received WW J. Detroit. (Right) J. D. Freed, signing a radio- frequency receiving set to receive long dUtsncoc on a loop aerial, and for modest distances without any aerial whatsoever. Mr. Freed (shown In the Illustration at the right) claims that ha has suc- cessfully overcome all the disad- vantages of radio frequency cir- cuits. (C. Kariel & Herbert \>w« Servirrl

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18 RADIO WORLD Aiyertiskgr R»tes, DitpUy, $54» ^rimclw $15000 per p«f* Radio Merchandising Classified Quick- Action Adyertismp, 5 ceats per wore Telephone Bryant 4796 Uncle Sam's Foreign Trade Expanding Because of Radio UNCLE SAM'S "sell-it-by-air" plan, the first practical application _ of broadcasting to business, is developing rapidly, Department of Commerce offi- cials state. Following the broadcasting from Boston, of the Department's trade opportunities throughout New England, many Chambers of Commerce through- out the country have asked for similar service for their broadcasting stations. Several of the high-powered _ radio sta- tions have offered their services to the Bureau of Foreign and Domestic Com- merce for this new and unique method of making public trade opportunities in foreign lands. The broadcasting station of "The Times," Ridgewood, L. I., is anxious to serve the territory around New York City. Another station, WFO, Dayton, Ohio, desires to receive information on the world's markets that it may be broad- cast to the exporters in the Miami Valley. A station at St. Louis has already begun to broadcast foreign trade notes, and the Chamber of Commerce, Buffalo, wants the data for use in two of its local sta- tions. It is understood that the Bureau ot Foreign and Domestic Commerce, Wash- ington, D. G, is considering sending weekly data to other localities where it will be distributed by radio to interested manufacturers and exporters. American Industry Best in Two Years A RECENT business survey issued by the Department of Commerce states that American industry is now marking up the best record for production since the period of depression two years ago. This increased output is general with all industries. Factory employment is larger than since December 31, 1920, which is held to be the chief factor in a more even distribution of buying power. Service Above Profits THE business world is going to yield more happiness to those who are en- gaged in conducting business, when more business men devolop the true scientific attitude of mind. Once upon a time an investigator used to try to keep the re- sults of his studies to himself so that he personally might profit by them. Now- adays research specialists give freely to the world whatever they have discovered that is worth while. They have placed service to humanity above personal profit. Some may consider it too idealistic to be carried through in the world of business, but the curious thing is that the business men who are practising this high idealism are making greater profits than they ever could by using a more selfish system. — Tom Dreier, in "Forbes Magazine." Measuring Shadows Time was when men climbed the pyramids with great effort find sweat- ing (for it is hellish hot in Egypt) and then after all this effort, often inaccurately, measured their' height. One day an old, lame man with a large staff hobbled out on the desert, stuck his support in the sand and measured its shadow. Then he measured the shadow of the pyramids and knew exactly their height. Some men measure the value of adver- tising by the loss of much money, sweat and toil. They pick out the oldest radio publication, or the one that claims the largest circulation, or the one that jams the largest number of advertisements to- gether, while all the advertiser is really seeking in spending his good money is to get consumer results: Orders, cash returns. Let us tell yon how to simply measure the value of your radio advertising dollar by the shadow method; that is, the result your competitor is getting from his adver- tising in RADIO WORLD— the results others have had from keyed advertise- ments where the same copy has been tested in each of the radio publications. This shadow measurement will give you an accurate measurement in advance of just the kind of results you may expect from RADIO WORLD. We KNOW and you can know it is the best buy in the radio advertising field. Write today to RADIO WORLD the only national illustrated weekly 1493 Broadway New York, N. Y. Heard at the Radio Counter A Conversation Between Customer and Radio Clerk HT WOULD like to know the difference be- * tween a regenerative receiver and a non- regenerative V _ "Well— you see, with the regenerative receiver, the plate circuit is broken and a coil, known as a tickler, Is inserted in series with the plate and telephone circuit. This is not in the non- regenerative.'* "Then, please tell me, what is its advantage 7" "It makes possible the reception of C-W, or continuous waves, which cannot bo received on the plain n on regenerative set. It also amplifies the signal immensely." "Well, I have a vario- coupler of the nonregen- erative set, and would like to make mine five. What must I do? What do I need 7" "You need a vario- meter placed in the plate circuit. This will do the trick. You also need another vario- meter in the grid circuit. This will make your set regenerative." "Will this work also with the crystal-type receiver?" "No. This will only work with the vacuum tube." "Well, If I use a vario meter, what will the wave lengths be?" "The wave lengths of this vario- meter receiver should range between two hundred and six hun- dred meters." "Let me see. I guess I'll take the vario- meter and try it out." "All right— sir. Let me know the results." (To be continued) New Firms and Corpora- tions (The Arms and corporations mentioned m these columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) SOS Radio Corp., Rochester, radio equip- ment, $25,000; H. H. Servis, R. L. Curtis. (Attorney, J. J. Mclnerney, Rochester, N. Y.) Radio Products Broadcast Advertising Corp., Wilmington, Del., manufacture, $500,000. (Amer- ican Guaranty and Trust Co.) Cairns Radio Mfg. Co., Manhattan, 250 shares preferred stock, $100 each; 130 common, no par value; active capital, $10,000; T. Cairns, C. Edouard, J. Eaton. (Attorney, G. L. Hess, 469 Fifth Av., N. Y.) Clinchfield Mica Corp., Wilmington, Del., $1,000- 000. (Corporation Trust Co. of America.) Uruguayan Telephone Co., telegraph and tele- phone wireless company in Uruguay and else- where, $1,000,000; Fits J. Porter, Otis T. Bradley, Leigh ton H. Coleman, New York. (Corporation Trust Co. of America.) Capital Increases Radio Craft Co., Brooklyn, $10,000 to $800,000. Home Radio Corporation, $10,000 to $35,000. Coming Events The editera of RADIO WORLD will gladly publish stews Hssns of all osntsespiatsd radas shows sod expositions. Keep as posted by f»f|in»ie; fall CHICAGO RADIO SHOW, Coliseum, Chicago, 111., October 4 to 22. U. J. Herssaaa, managing director, J49 If cCormick Building. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, inclusive, ISOL George A King, director of publicity, 417 South Dearborn Street, Chicago, JDL PERMANENT RADIO FAIR FOR BUYERS. Hotel imperial, New York City. Open from September, 1922, to May, 190. AMERICAN RADIO EXPOSITION, Grand Cen- tral Palace. New York City, December 21 to 11, Company, Fisk Building, New York, N. Y. TRI-STATE TOBACCO GROWERS' RADIO SHOW, Covington, Ohio, October 21 to 2S, in- clusive. INTERNATIONAL RADIO SHOW, Madison Square Garden. New York City, November 20 to IS, Inclusive. E. C Buchignani, director of pub- licity. SOUTHEASTERN RADIO EXPOSITION, Audi- torium Armory, Atlanta, Georga, December 4 to 9, inclusive. Jump in Radio Sales ALFRED FANTL, financial writer for "The Tribune," New York, one of the close observers of commercial condi- tions in the United States, published the following in his department last week : A sudden and large jump in radio sales occurred during the week, when many department stores sold as much in a single day as they had previously dis- posed of in the course of one week. .The impetus, while in part due to fall revival of interest in radio, owes much of its suddenness to the enterprise of the press in reporting the world series via the air — a demonstration of radio's practical utility which could have no more sus- ceptible portion of the public for the making of an impression at once instant and profound. Digitized by Google

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RADIO WORLD 19 New Circuit for Experimenters 2Zi Volts/ The above schematic diagram la a hook-up of a single-coil receiver. It is the work of Mr. W. Millar, Southern Methodist University, Dallas, Texas, The amateur who delight* in experi- menting should give this circuit • trial. A duo-lateral coil, No. 54, is inserted between the aerial and the ground. The grid condenser and leak are connected in die circuit of the coil and ground. The plate circuit is brought to one side of the aerial and, also,' to one aide of the tele- phone jack. Careful adjustment of the set Is necessary. Radio World requests all amateurs experimenting with this circuit to make a report to its Technical Editor as to its receiving qualities as well as to the distance secured. Facts You Should Remem- ber About "Litzen Draht" THE advantage of litzen draht, a wire made in Germany, for winding induct- ances with a very low resistance and having a large surface, is recognized. This wire is composed of a number of enameled copper magnet wires separately insulated from one another, and braided, the whole covered by a single-braided silk wrapper. Litzen draht is employed in research laboratories and particularly where high efficiency is re- quired. The following describes the number of wires, the size, and the number of feet per pound. These facts are of vast importance to every amateur. 4 Wires, No. 28 B&S (Brown & Sharpe gauge), made up in 4 strands of 6 wires each, enameled, with silk wrap. The strands are cabled around a hemp core and the whole covered with 2 wraps of green or white silk. 3835 CM. (circular mill), No. 14 B&S ; approximately 90 ft. to the pound. 30 Wires, No. 36 B&S, made up in 3 strands of 10 wires each, cabled and served with 2 wraps of silk, 750 C.M„ No. 21 B&S ; approximately 332 ft. to the pound. 90 Wires, No. 38 B&S, made up in 10 strands (3x3), enameled, with one wrap of white silk. 1415 CM., No. 19 B&S; ap- proximately 225 ft. to the pound. 48 Wires, No. 38 B&S, made up in 6 strands of 8 wires each, enameled, cabled with 2 wraps of natural, black or green silk, 775 CM., No. 21 B&S; approximately 415 ft. to the pound. 48 Wires, No. 38 B&S, made up in 8 strands of 6 wires each, enameled, with 2 wrap* of natural, black or green silk, 775 CM., No. 21 B&S; approximately 415 ft to the pound. 10 Wires, No. 38 B&S, enameled, strand- ed^ with one wrap of silk 155 CM, No. 28 approximately 1<s0° ft- to the pound. 20 Wires, No. 38 B&S, enameled, strand- ed, with one wrap of silk, 310 CM., No. 24 B&S ; approximately 800 ft. to the pound. 120 Wires, No. 40 B&S, made up of 3 strands of 40 wires each, enameled, with 2 wraps of black silk over all, 1200 CM., No. 19 B&S ; approximately 250 ft. to the pound. 32 Wires, No. 38 B&S, 4 strands of 8 wires each, enameled, with 2 wraps of black silk, 500 CM., No. 21 B&S; approximately 605 ft. to the pound. 48 Wires, No. 38 B&S, made up in 3 strands of 16 wires each, enameled, with 2 wraps of natural silk, approximately 400 ft. to the pound. 10 Wires, No. 40 B&S, stranded with 2 wraps of colored silk, 99 CM, No. 30 B&S; approximately 3000 ft. to the pound. 162 Wires, No. 38 B&S, made up in 18 strands of 9 wires each, enameled, cabled, with 2 wraps of green or white silk, 2250 CM, No. 16 B&S; approximately 125 ft to the pound. 36 Wires, No. 38 B&S, made up in 6 strands of 6 wires each, enameled, cabled and served with 2 wraps of green or white silk, 566 CM, No. 22 B&S; approximately 500 ft. to the pound. Cleaning Files X/TANY amateurs experience trouble ■L'-l when they attempt to use a file on some of the softer metals, such as lead, aluminum, copper, says "The Mail," New York. This is due to the metallic particles clogging the teeth of the file, thus render- ing them ineffective in cutting the metal. In some cases the metal particles clinging to the file will scratch the object being filed, making a rough surface. This difficulty can be overcome by rubbing the surface of the file with ordinary stick chalk, such as is used for writing. The presence of the chalk on the surface of the file and in the crevices between the teeth is to prevent the Wings from sticking and filling up the cut- ting surface. This same result can be ob- tained by dipping the file into hot water For best results equip your Magnavox Radio with Magnavox Power Amplifier THIS apparatus has been placed on the market in response to many re- quests for a power amplifier giving distortionless amplifica- tion of music and voice, pre- vious amplifiers having been developed for signals only — where distortion does not show. To accomplish the desired purpose, the Magnavox Power Amplifier had to be especially designed, and internal circuits, grid potentials and amplifying transformers are entirely dif- ferent from those in other am- plifiers. Any of the standard tubes can be used. The use of the Magnavox Power Amplifier insures getting the larg- est possible power input for your Magnavox Radio. Switching from stage to stage is made easy by master switches, as illustrated. Brushed bakelite panel, mahog- any case, without tubes or high vol- tage batteries. 3-stage, AC-3-C, Price... $110.00 2-stage, AC-2-C, Price. . . 80.00 The Magnavox Power Amplifier, Model C, was designed for use es- pecially with the Magnavox Radio, and is made with the same insist- ence upon high quality and efficient service. Magnavox products can be had of good dealers everywhere. The Magnavox Company Oakland, Cal. New York Office, 371 Digitized by Google

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20 RADIO WORLD RADIO FANS Rrfeclion in RadicT Headsets attained in .1 L_ ■■in* give clear, distinct tones, reproduce perfectly the most sensitive radio sig- nals in music, speech and code. ; No matter how perfect or ex- pensive your apparatus; no matter how strong or perfect the waves; without "ECHO HEADSETS" your results can- not be perfect. We ship phones the day your order arrives. Every pair tested, matched and guaranteed as sensitive as the most expensive headsets made. Sold with money-back guarantee. Sent C. O. D. by express, who will hold money for 48 hours' trial, if not satisfied express com- pany will return money. S. Pearson RADIO Co. 142 Maple Street Richmond Hill Long Island, N. T. 35* S tar 11.00 NA-ALD GENUINE CONDKN8ITK DIAL ^^^m The dial that runs true. Numerals ensraTed on bevel and knob ao shaved that fingers do DM bids them. Thin edge Kith clear graduation make accural* reading easy. Concealed set screw In metal Insert. Will not warp or chip. Finish and enamel permanent «" dial 36s 2'A" Mai for rtwsrtat sttsatlmsnr 35. S%" dial 75* Bend stamps (or complete literature. ALDEN • NAPIER CO. 02 Willow «t, Dos*. L. SsrlMfMd. Mass. If you did not get copies of Radio World No. 1 to No. 26, send as $3.00. Or we will send yon this paper for one year, ($6.00 for 52 issues) and start it with oar first issue, which will be mailed you ao toon as possible after receipt of order. Every Member of a Radio Set Is an Auxiliary Policeman IT is announced that arrangements have been made to equip the metropolitan police force with a comprehensive radio out- fit. This is the happening of the expected — not to say the inevitable, says Henry Smith Williams, in "The American,'' New York. Radio has such obvious possibilities as a police agency that its use in this field must become universal. Already important beginnings have been made. Out in Chicago, for example, the police department has been using radio- equipped automobiles for some time. Patrol wagons have been equipped, experimentally, with wireless outfits that keep them in touch with headquarters at all times. It is re- ported that perfect communication has been established, the tests being satisfactory in every way. When a crime or disorder is reported to headquarters by ordinary telephone, word can at once, be flashed by radio in every direction and a universal alarm given in a fraction of the time previously required. The entire police force might thus be on the lookout for a criminal attempting to es- cape in an automobile, and the probability of interception of the fugitive enhanced enormously. An obvious difficulty that suggests itself is that the ether may be vibrant with other messages. Broadcasting stations, for ex- ample, are busy at almost all hours of die day, to say nothing of commercial and ama- teur stations. The difficulty is to be met in New York — and doubtless the same expedient will be adopted elsewhere — by alloting to the police department a special wave length that is not to be used by any other radio station in the vicinity. The wave selected for the metropolitan district is 400 meters. It remains to be seen whether messages on this wave-length will interfere with the 360-meter wave used in general broadcasting. If it does, a larger wave, perhaps 500 meters, will be employed. With radio-receiving telephones of the newer type, equipped with loose-couplers and condensers for accurate tuning, there should be no difficulty in shutting out the broadcasting program while listening to the police messages, or vice versa. But less elaborate sets, not being able to tune sharply, may mix up concert and lecture with re- ports of robberies and murders in distract- ing fashion. But at worst this will serve as an incentive to the radio fan to improve his apparatus. Meantime, every owner of a receiving radio set becomes potentially a member of an auxiliary police force. Radiofacts Transmitting sets are essentially the same as receiving sets with the exception that they must have a source of power, and of course the apparatus must be so designed that it will carry this power. The microphone is the most important electrical mechanism in the transmitting studio. It plays a part similar to the trans- mitter of the ordinary telephone by picking up sound waves, causing the diaphragm to vibrate and create corresponding changes in the current flowing through the circuit. The capacity of a storage battery is gov- erned very largely by the quantity and qual- ity of lead and oxide of lead used in. its con- struction. Two things must happen to the radio fre- quency currents before they get to the phones. 1st — They must be allowed to move the diaphragm of the telephone. 2nd— They must move it at audible frequencies— below, say 4,000 cycles per second which is the top note on a piano. Reliable and Beautiful RADIO-A RE -CHARGER THE RADIO-A is a highly efficient dependable piece of apparatus, absolutely fool- proof, easily attached by sim- ply plugging into ordinary 110 volt lamp socket. In case of current failure, the unit cuts out automatically until current is resumed, without discharg- ing battery. It is designed expressly for re-charging radio filament bat- teries, but may be used for automobile or any other stor- age battery of reasonable size and capacity. Price, $18.50 Dealers and Distributors Here's a Winner! Write as for fall particular*. Simply screw Into any 110 volt lamp socket and connect the terminals to roar battery. Impossible to hook-op RADIO-A charges either way. A compact portable Re-charging Unit that will folly charge a 100 A. H. Bat- tery overnight, (or from Sc to 10c, ac- cording to prevailing rate*. LAST A LIFETIME King Electric Mfg. Co., Inc. 1681 FILLMORE AVENUE BUFFALO, N. Y. — Bogle DiailiiuU U'

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RADIO WORLD 21 NA-ALD SMALL SPACE V. T. SOCKET Jit talk. S far $1.00. m»ul to lnt«rfar« irltb eiriclaner- UnalTartad of bulna ar •olJarinn Iras. Pboapbar »nlifl». Ntakal plated ' ■baa ant aloe Price SpeotoJ proposition /or denieri and jobber ». ALDEN-NAPIER CO. D«pt L U WUlaw St. MICON Tested Mlea Conden»er bIt ruaraaaatd uaaaleaa eoodanaw of abertuulj mt eapealrj Made In t05 and .0015 m. f . d. loan. aaoaaallT far thli drault. It max ba bad In all etjae tram .000025 to .01 absolutely «njalaa>. wnlch la aaianUal wit* tha Arm- ciieutt ■ ICON .0011 a. f. a. •••00 MICON .003 e>. I. d. 74 It ,«ur dealer eu.ru* euwli 7011. eand us hla name aad 11.10 and ratat'a tha two M1CONS poatKald. and a oaatpieta atroult duuram of the new ABM- BTBONO Circuit absolutely free. FRESHMAN COMPANY. INC. Twenty-One Stations to Broadcast Navy Numbers IN co-operation with the Navy League, 21 broadcasting stations will include special Nary numbers in their programs on Navy Day, Friday, October 27. At some stations, speakers will narrate on the history and the prowess of our Navy; at others, Navy musicians and vocalists will render musical selections, while a few will broadcast programs now kept secret in order to surprise the listening radio enthusiasts. The only government station on the list is the well-known NOF, at Anacostia, where most of the governmental programs, in- cluding the famous Marine and the Washington Navy Yard Band Concerts are broadcast. The stations listed by the Navy League to date are: The four Westinghouse stations, Springfield, WBZ; Newark, WJZ; Chicago, KYW; and Pittsburgh, KDKA ; General Electric, Schenectady, WGY; Detroit Free Press, WCX; Southern Radio Corpn., Charlotte, WDT; Richmond-Crosby, Memphis, WKN; St. Louis Post Dispatch, KSD; Tulano Univ., New Orleans, WAAC; The Times Union, Jacksonville, WDAL; Reynolds, Denver, KLZ ; Spokane '•Chronicle," KOE; "Desert News," Salt Lake, KZN; Kansas City "Star," WDAF; Atlanta "Journal," WSB ; Dallas "Nev WFAA ; Oakland "Tr Great Falls "Tribune," "Star-Bulletin," KDYX. Listening-in Association Formed A DECIDED increase in popular in- terest toward radio is promised. The larger broadcasting stations have installed more elaborate transmitting apparatus and equipment; all stations have profited by their experiences the past few months. Listeners-in will in- crease in number. All listeners-in — dependent as they are on the nature and variety of broadcasts for their entertain- ment, and on the quality of the receiving apparatus used— would desire naturally a medium for the exchange of their views and comments. The National Radio Listeners-in Asso- ciation of America is an organization formed in Washington without capital and with no commercial interest. Its object is to encourage cooperation be- tween operators of broadcasting stations and the greatly increasing numbers of listeners-in included in the term "general public." The bi-monthly meetings have satis- factorily affected changes in such matters as increased range, improved modulation and details of performance pertaining to individual artists appearing on programs. First results noted locally, encourage the members of the association to sug- gest similar action in other communities, welcoming any request for assistance and seeking helpful suggestion. Comment or suggestion in the interest of the public and radio are cordially invited. The officers of the new association are: L. C. Hedges, president; James W. Cook, vice president ; O. J. Hodge, chairman, board of critics; M. D. Meyerson, chair- man of publicity; H. W. Ennes, corres- ponding secretary; William A. Eaton, treasurer. Address: 901 Varnum Street. N. W., Washington, D. C. • RADIO WORLD to of ] YOUR NEV to ba aura of getting RADIO WORLD on either eubecribe direct or I U-M tfaroa World, MM SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, Ntw York City. mt RADIO WORLD for _ months, for which % • o a o • I ■UBSCHIPTION RATES: ma** Copy » u Throa Mentha 1 50 mm Mini .3.00 On* Tear (53 leeuee) 6.00 Add H.0B a Year for Foreign "RADIO" VARIABLE CONDENSERS These condensers are the Standard of Quality. Carefully tested, inspected, balanced and adjusted to give satisfaction. 3 plate V 51.50 Sent prepaid on receipt of price. Special di.count. to Radio Club*. Jobbers and Dealers write or wire for the biggest prop- sition in Radio— TODAY! FREDERICK H. PRUDEN INCORPORATED LERNER BUILDING ••3 Bergen Ave. JERSEY CITY. N. J.

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22 RADIO WORLD Radio Patents Schematic diagram showing ■ modification of th* ground antenna of the Hanson-Jonas Invention, with moans for varying It* capacity constant. Underground Antenna No. Ma^M. Patented, September IS, 1922. Pat- entees: Earl C. Hum, Washington. D. C, and Edward F. Jonas, Now Orleans, La. THE object of this invention is to provide an underground, or sub- terraneous, antenna-system applicable for installation within a limited area; also, to provide for varying the conson- ants of the antennae by directly modify- ing the capacity of the antenna collectors. Experiments have determined that under-the-earth antenna construction, such as Mr. Hanson has devised, possesses feature of distinct advantage over under- ground systems heretofore employed. The concentrated capacity-area gives the same effective antenna-surface as long, buried single-wire conductors, and gives substantially the same signal energy as the long, buried conductors. It has been found that placing the capacity antenna areas a distance of, approximately, fifty feet apart, radio signals have been re- ceived from considerable distance and at high audibility. Radio waves progressing in the earth's crust will induce a charge on the antenna capacity-areas due to the elec- trostatic component of the radio wave and the antenna circuit will oscillate due to the phase relation of the charges impinging upon the capacity areas. Under certain conditions, satisfactory results are obtained by using smaller antenna capacity-areas and, therefore, the variable antenna capacity-system may be utilized for a wide range of wave lengths. Where stations are required for operation on predetermined wave lengths definite capacity areas may be employed. However, where it is neces- sary for stations to communicate with numbers of stations operating at various wave lengths the means may be used tc change the effective area of the capacity to obtain syntony with the cooperating station. In the practical operation of the Han- son system, it may be found advantag- eous to have the antenna capacities placed directly beneath the station and allow the rotating handles of the variable antenna-capacities to project through the floor so as to enable the operator to readily control the capacity values for various wave-lengths. The system is not limited to operation over only a small band of wave lengths, but ia applicable for long-wave operation such as is em- ployed by high-power oceanic stations. * * * Low-Frequency Amplifier No. l,42t,lM. Patented, Saptamber 5, UBS. Pat- ontaot Lloyd Espenschled, Houis, N. Y. THIS invention relates to the am- plification of low-frequency sig- nals, such, for example, as ocean cable, telegraph signals or those emanating from the propeller or engine noises in submarine detection. Such signals have a large, or predominating, direct cur- rent or very low-frequency component which is not transmitted or inefficiently transmitted through the ordinary repeat- ing coils used in the local circuits of thermionic amplifiers. An object of the present invention is to provide an ar- rangement for amplifying signals of this character which will amplify all low frequencies, including the direct cur- rent, without the necessity of a metallic connection between the successive stages of the amplifier and without the attendant difficulty of preventing the output battery of one stage from af- fecting the input circuit of the succeed- ing stage. The invention, in many of its aspects, is equally applicable to the amplification of signals in any order of frequency. A further object of the invention is to increase the amplification to telephone currents, or to carrier currents, over that obtainable by} the usual vacuum-tube amplifying circuits, by the use of feed- back circuits. In general, the invention consists in the modulation of an alternating current, of a frequency, say, of 1,000 cycles per second or higher, by the incoming signal impulses, the amplification of the mod- ulated alternating current and the de- modulation of the amplified current. * * * To Prevent Loss of Energy No. MZt,4B. Patented, September It. M22. Pat- entaai Harold J. Powsr, SomarvUla, Mass. HAROLD J. POWER, vice-president of the American Radio and Re- search Corporation, Medford Hillside, Massachusetts, has been granted letters patent on an inductance device which should prove useful in that important phase of radio. In certain electrical current carrying instrumentalities, of Figure 1 is a top plan view of an In- ductance device arranged In accordance with my invention, and Figaro 2 Is an en- larged vertical section on the line 2-1* of Figure 1. At IS and 11 are ahown boner and outer supporting members of any suitable insulating material. which inductance devices furnish an ex- ample,— and especially those employed in connection with such high-frequency currents as are present in wireless or radio installations — it is important to prevent the loss of energy from the con- ductors rjirough their insulating sup- ports, and to so compactly arrange the devices that little space is occupied and. further, so that two or more of the de- vices may be brought into close rela- tion to produce a mutual effect s low-frequency amplifier. aft Digitized by Google

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RADIO WORLD 25 L 1M0 turn Dls 1.00 ■!.«• triple ron. nmxiiM.N Complete, with VARIOCOl'FLER Special, rood type WJ At'DIO FREQUENCY TKANKM>KMKK General Radio variable: condens— .•01 Mfd.. J at ea *tM FIXKD COND«UH Best Mica. .00* M(d 40. Beat Mica, .OOtl Mid 4 Or. Best Mica. .001 Mfd See. Beet Guaranteed. Ufa V Me. I •••»«» else, file V fl.SA 45 Volt ....■.■*..■■.■•..■.>•**«•.■•>•».■ .as.ss - M M \VS ON HAND. RADIO DISTRIBUTING & AUTO SUPPLY CO. 64 West 66th St, New York City Broadway or 7th Avewoe Nobwwy •th or tth Arena* These Prices Do Not Include Poets fa Digitized by njOO^IC

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24 RADIO WORLD $4 CRYSTAL SET THE LITTLE WONDER- $U4 UNMOUNTED Wonder in name and a vender ta fjr- iormance. Cannot be equalled lor the price. Catches diatinctly everything with- in 25 miles. Send for FREE catalog, deecriblng ear "Little Wonder" act and lilting radw sup- plies. All i cut te HOLLOWAY ELECTRIC SUPPLY CO. Third Avenue New York City UNIT RADIO SETS Oar eeta approved and hutalled te PreeU—fa Offlceo of Qneeaa , New York City. PRICK and QUALITY our premier coneideration D*t**t~ Uslts »••• J. $!».•• AmtW* Ualt* *» »•••• Taaw Ualta..... • D*m**r sod I Ma JJ.M Deutter sod 2 flia JJ JJ Taalu Ualt DMMtor sad I Stay tt.M Declare write far proposttjoa Immediate Delivery American Radio St Electric Co. US Broadway, New York CJty TUNE IN DISTANT STATION F. R. S. Complete Two-Stage Long Diatanca Receiver Bat Include* two Federal Transform «ri Ondnt, two variometer*. Ttriooouplm. time V. T. sockets, fllsment rbeotut*. dial*. Bead Km Undloi posts, nrltoh point*; In utraetlTO cabinet and drilled panel: oomptou, ready ta • ja f\ book up. A tltt Radio. 40 F. R. S. All-Ware Combination Molded Jfi no Variometer* »O.UU Molded tC. OQ Variocoaplera *}9.VV $5.oo Bank winding 1* lnterchuuteible (or us* with either VtrloaxUr or V*rloeouptar. TM* 1* the only ill molded unlTerwl eombtna- tlon glTlnt fin unit* In three. Ft* q RADIO • K. O. CORP. 409 Eaat Fort St. Detroit, Mich. 531 SO. DEARBORN ST.. CHIT- Creed System to Speed Up Code RADIO code-communications _ from ships and land stations, which ra- diophone users frequently hear as they tune in the broadcasting concerts, are transmitted by hand, generally at a speed ranging from twenty to thirty words a minute, says "The Times," New York. Since the early days of wireless various methods of automatically recording mes- sages at high speed have been developed in order to facilitate the clearing of heavy traffic in the shortest time possible, espe- cially between long distant points. The high-powered trans-Atlantic transmitters and receivers are in constant operation, day and night, handling the hundreds of radiograms and press reports between Europe and the United States. To use a speed of thirty or even forty words a minute would require many hours to get the latest press news and business mes- sages across the sea. One of the latest methods of speeding up radio communi- cation is know Creed system, which is applicable at the present time for com- mercial work at a speed of 180 words a minute. One of the greatest problems in the operation of printing or recording radio apparatus is the necessity of accuracy qf the signal form; that is, the duration of the dots and dashes. The accuracy re- quired for mechanical or automatic re- ceiving must be carried to a much higher degree than if the reception is through a headset and the human ear, and more particularly so when high telegraphic speeds are used. For the operation of the high-speed mechanism it is necessary to insert a mechanical relay between the valve circuits, A relay in this case is an instrument actuated by the radio currents after they are amplified to sufficient strength to cause the relay to operate and control other instruments in the circuit. The new relay used in connection with the Creed system was developed in Eng- land and has features which overcome many of the difficulties and deficiencies existing in mechanical _ relays. _ Its salient points are: stability of adjust- ment, firmness of contact, pressure and absence of rebound, sensitivity, shortness of transit time and ability to work at high speeds. In connection with the Creed system the signals are transmitted in the ordi- nary continental Morse code. The im- pulses are picked up by the antenna, wires are passed through special vacuum tube amplifiers which build up the sig- nal strength sufficiently to actuate the relay, capable of following the dots and dashes perfectly up to 200 words a min- ute with a current as low as one-quar- ter milliampere. The relay in turn operates a perforator which punches the dots and dashes on a paper tape. This tape is run through an automatic typewriter which records the mes- sages in print on another tape. The new features of this relay are ability to follow at high speed and at the same time work with entire _ fidelity on such a feeble current. The inertia of all the mechanical parts as well as the electri- cal magnetic circuits have been so finely calculated that the maximum efficiency, theoretically possible, is produced. That Armstrong Circuit So much Interest baa been displayed tn the apeclal article, "TB8TED INVENTION OF" MAJOR ARMSTRONG AMPLIFIES 8BT 100.000 TIMES." by John Kent, that appeared lo RADIO WORLD No. 13, dated June 24, 1923, the publisher decided to pat aalde • number of copies for those who were not able to set this issue when published. Copies will be sent, postpaid, on receipt of 15c. or aead in your subscription, $6.00, for one year (52 issue*) . fS.OO six months, or $1.60 three months, and subscription will be started with the Issue con- taining the article about Major Armstrong's \ mpllfler. — RADIO WORLD, 1498 Broadway. >ew Tork. AGENTS Wanted in every city sad town to aeU radio apparatus. Good commiooson*. A lew stocking agenciee open to reliable parties. DELANCEY, FILCH * COMPANY l> II i ilia i St- GOING — and Going Fast W* asm eat/ a few tart sad •» test, sat «Mm any last w* wW Ml nam at the names r " VT 1 Detector and VT 2 Detector and »*. "RADIO BUILDER" PLANS FREE! By Man. (a. LIBERTY RADIO CO. Ml Liberty Street New York Carj ~ Radio Supplies' Variocoaplera, Headsets, Sockets, Rheostats, Etc -mST* Crystal Set $A PRICE, *I Or Money Send fifty ctntt far 20 eficient blue-print hooh-upt. Any Radio Set Mad* to Order or Repaired Sunbeam Electric Co. 71 THIRD AVE. NEW YORK "MIRaAD" "Qnaliry Ratio Priced Right" S Plate Variable Camaaamoto $LM Mh-ad Varicoupiere US SMS Ohm Double Hand Phonos tM ISM Ohm Single Head Phone Mt (Money bach guarantee.) Mh-ad a Plate Condsassr Mo Mired 4S Plate Variable Cesmsaeer . . . . 4Jf Mh-ad Detector Ualt (Mt Mirad Two-Stop Amplifier SMS Postage Paid Dealers' Sample of Above S% Off Miracle Radio Mfg. Co. INTERURBAN BLDO, DALLAS, TEXAS PHONOTACH Makes Your Phonograph -j Radio Loud Speaker (Trade Mark) AdHut it in a minute. Patent applied {or A New and Better Loud Speaker at * very low cort The PHONOTACH connects the receivers with the tone arm of your phonograph. Utilizes the scientifically designed tone amplifier of the talking machine to mellowness and beauty of tone. Price only $2.00 Send for on. toduy--At your dealer, or by mail W. A. MILLS 103 Park Ave., New York, W. Y. Digitized by Google _

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RADIO WORLD 25 The "Why" of the Farmer's Happy Life FER years an' years th' most serious drawback t' farmin', next t* th' hard work an' element o' chance, has been that it isolates a feller an' keeps him out o' touch with th' affairs o' th' world. Fer many years most farmers had t' manage t' git along fer weeks an' months without hearin' from th* outside world. It wuz hard fer 'em f remember who th' president o' th' United States wuz, an* they didn't know whether ther friends an' rela- tives wuz dead or alive unless a letter or newspaper wormed thro', or by chance they got t' town. Then come th' telephone an' rural free delivery, an' th' farmer wuz fairly able t' keep a line on his relatives, European af- fairs, and th' price o' eggs. Then th' automobile bobbed up an' is. a big factor fday in bringin' th' farmer's relatives f bis very door, an' also in whix- zin' him an' his family t' town for a band concert or a hall show. But drivin' t' town ever* night, or havin' th' borne full o' relatives soon gits t* be a chestnut, an' besides it eventually runs into money. We believe mat next f th' barvestin' machine an' a pump in th' kitchen th' best an' so fer th' cheapest thing that's happened fer th' farmer in many a day is th' inven- tion o' th' radio 'phone. The' radiophone's performances already have proclaimed th' end o' isolation. Th' fanner no longer has t* drive t' town, or entertain a house full o' hungry relatives, or depend on a day-old newspaper fer his newt o' th' outside world. Th' seas an' lakes an' continents, burn in' deserts, frozen wastes, an' mountain peaks, have all been over passed. Th' farmer an' his family may now know when a car is stolen from in front o' th' courthouse, or when a schoolbouse is burnin' up, or when a treaty is signed, as soon as th' ether waves kin deliver th' news r* ther vocal loud, or speech amplifier. After a hard day o' toil th' fanner, with- out even changin' his collar, or rollin' down his sleeves, kin tune in an' take his pick out o' ever'thing in th' air. An' all about him sits his family f hear what* s gotn' on in th' world in th' way o' news, singin', music, an' oratory. If they tire o' th' 'Wabash Blues,' they kin tune in a lecture on onion culture, or th' treatment o' hog cholera, by some expert in Detroit. Maybe he kin pick up a saxophone solo from Hurley, Wisconsin, or a bagpipe sex- tette from fer-away Scotland. Maybe his congressman is sendin' out words o' cheer, or there is a fire in town. It's no uncommon thing f jest innocently tune in on a fine helpful sermon from Pitts- burgh, or Wheelin', an' it's no trouble t' tune off o' it. But ther's no longer any excuse fer folks that are imprisoned on remote farms t' git behind on th' affairs o' th' world— not t' be able f whistle th' latest airs, t' know when th' President misses a chance to play golf, t' keep track o' th' bonus bill, an' all th' latest gossip about prosperity. — Abe Martin in "Farm Life." w Experienced Stage-Fright When Broadcasting HEN the red light is turned on youH know 'you've got the air,'" said Herbert S. Houston, publisher of Our World, on his return to New York from a trip West, to the Advertising Club News." "This was the signal," he went on to say, "for my first experi- ence in broadcasting an address. It was in the big radio station of the St. Louts 'Post-Dispatch' and I was broadcasting an address on "What Europe Means to the Mississippi Valley.' I think I can truly say that jhe only time I was ever seized with stage-fright was this par- ticular time when I wasn't on the stage —but instead, talking through a micro- phone to a vast invisible audience. "A few minutes after I concluded my address a telephone bell rang and an attendant said that I was wanted on the phone, much to my surprise. George Burbach, the advertising manager of 'Post-Dispatch,' had called in from many miles out in the country to say that he had just heard my radio address and that he heard every word distinctly and perfectly. It all seemed most marvellous — even in this age of marvels — that one could broadcast an address by radio and then be called on the long-distance tele- phone to be informed that the address had carried across." ABC Standardized Radio SecMaaal ■aoahrtav Uate aad Ratto I give ■■atiittflaal eattoacMea at bv Write t Mamrfactarms Corp. Ait, Dae* O. New Yerk CORACO RADIONCONCERT Dally. 1 A. K H | f, M. I Mi rt—r. Ill w. 42nd St.. mmt to AmtffdiH Thtatra Th* Cbnn Burjar- Radiophone La th* Utoat alaaltal Iwiiiwilll In nulla. It hu n. outakla to oparata aa • uhaaaaianh I writ, for full Information. THE CORACO COMPANY. INC. 22* Wat 42»o Strait Nta - R m SOMETHING NEW! Variable Condenser Built Right Made in the most popular sizes, with aluminum plates, cast end brackets, with a 1" diameter Bakelite bushing therein. (A perfect insulator high in dielectric strength). Dealers write for discounts. Ask to see our Rheostat ami Vacuum Tube Socket. LOMBARDI RADIO MFG. COMPANY 67-71 Minerva Street, Derby, P.O.] Patent Applied For « «0> ^.ts^ss: PANELS A ffi«h «■«■*■ Fa** Can i Hat to Was*. WkSMtrt • Bar*. Highly PaltahaJ Eigm ' Staetori toaa, Talf^U. TMlSaS/M, TaStU/M, MkUkI/M, and UmUO/M. fc» aeaafc jar to- af tto aaaaa aWr. BMtaa peata, aaala, aavi kaaba ta aaatck. We hove • tl— jlHl toe el Cato, Valla Hin, VaTtaeeaaawa, Sectota aaat Ramie ti. Largest Discounts. careful attention given •I WrlH to- ptmrnrn- TO ALL RADIO ENTHUSIASTS ALLIED RADIO COMPANY. INC Dae*. D, eSJ SEVENTH AVENUE, NEW YORK CITY. " For CORRECT RADIO MAILING LISTS Usa THE POCKET LIST Wa ks*a ha aiaMninj awaTal ta mm ta tt tkat atari Mtaattaaia. JaMar aat Daakt a aval mm. aadar tka FBOnBCQMROAnOK. to ariaaa aa nil awna aaaa teas 1101 mtTrnmS aa Had aad, aa a raJax thaw imn | an far baa hatae aanart. oaaaae Mtt mm mm mm mum. mm faa alllite H ta ha mm mm/ mm mmmmmm mmmmt at mm mat Ointii Meat raadj far lillil i aaaaaear ssta. Maa SS.eS ear mmt. m tlS.H mm mm (mm hv szjrtsz toto.-nirs: s» a^tor--,,,i»"*r,r-,h-- Fn DTfMf 17NC Mn CAJUUNOTOM STRUT a Lf. A IV^IWdl^laJ, JANESVUJLE, WISCONSIN "TUNING IN" TO THE RIGHT TUNE IS VERY SIMPLE WHEN YOUR CONNECTIONS SOI DERED WITH THE NEW "POST SOLDERING IRON ft (Tto Iraa wttt. i Oaatfnad aapadaOy ha cevar evary afliciaat baatruwat ea tto ■arfcc IMt). H Actual 9b* LIST ff~M POST ELECTRIC COMPANY SS EAST 42ND STREET, Div. SSt Digitized jyj

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26 RADIO WORLD Sidbenel Radio Equipment Mfg. Co. Dept. "B," 1663 Jerome At*. NEW YORK, N. Y. 22 to 500 Volt "B" Batteries Write for free catalogue on parts Answers to Readers / have a three-coil regenerative set. May both variable condensers in this set have 43 plates t Is there any difference in the primary Tillman's Potentiometer Fast Seller On* of the finest products on the market. Has the fol- lowing special features: 1. MADE ENTIRELY OF BAKEUTE 2. FREE MOVING AND SILENT LEVER j. THREE UNIT BINDING POST t < at lapaB Other high class items. Price flM Prepaid, cash with order or C O. D. RADIO FREQUENCY SETS Four Tube* good for 900 mile* on Loud djrtC A A Speaker, Completely Assembled eBJIsJ.W Antenna Light Wire Plug Radio Frequency Transformer *••» "general merchandise company MANUFACTURERS AND DISTRIBUTORS 142 MARKET STREET NEWARK, N, J. GREWOL DETECTOR $2.00 Nothing Like It Nothing as Good The Oreml DaSeetor bu .Ma its else. - - tba sUadanL nauooaUy aayairUsad parte . In a olaaa by luelf bceaoM it does what no deteetar bu Tec been developed to do and still sails at a popular price. Aaked (or by name, sold by reputation. una |2 sad we will til yaw ardor. Year Dealer ha* Brmb) Always Set and Ready Glass Encased (Actual Size) Super-Sensitive RANDEL WIRELESS CO. Sole United State DUtributort 9 CENTRAL AVENUE NEWARK, N. J. XRADt » MA1t*V THE COMPLETE LOVD SPEAKER _No "units," headsets, extra batteries or adjustments required. Complete witb cord, ready to connect in, in place of your headset. LOUDNESS — Just a sample of actual performance. In our test- ing laboratory, using a small outdoor aerial and an ordinary set with two stages of amplifi- cation (the ideal set for aver- age conditions unless near a broadcasting station) we have received broadcasting stations more than six hundred miles away, so loud it can be heard a hundred feet away. Or again, while this compact little instru- ment (it stands less than eight inches high) is designed for home use rather than for large halls— yet with the same set stations thirty miles away come in somewhat louder by direct comparison than a full sized phonograph playing a loud rec- ord with a loud steel needle. And TONE— While we wel- come comparison on loudness, what will really impress you "Spirals Speaks" most about your SPIROLA CONCERT is the tone. We have absolutely eliminated distortion and all metallic, "tinny" qual- ity. Violin, orchestra music, voice, even the difficult piano come to you through your SPIROLA so clear and natural you can hardly believe they are not in the same room. . Beautiful cabinet type, choice of dark oak or mahogany fin- ish, bronzed throat; at your dealers or prepaid anywhere in the U. S., Canada or *1 o CA England * .,, J1 We are so sure you will be pleased with your SPIROLA CONCERT that we absolutely guarantee it. Ifyou wish to re- turn your SPIROLA for any reason whatsoever, do so within ten days and your money will be immediately refunded. Made and sold by L. H. Donnell Mfg. Co., Dept. B, Box 70, Ann Arbor, Mich. REPRESENTATIVES WANTED! pSSShmn: RADIO WORLD, 14» Broadway, New York City. condenser if placed in the aerial, circuit in- stead of the ground lead? Will a plate bat- tery having variations of 1J4 volts give sharper tuning t— Joseph Lamkin, Minne- apolis. The variable condenser in the aerial circuit works best with a 43-plate variable condenser which is .001 mfd., capacity. The other variable condenser is of the 23-plate type with a capacity of .0005 mfd. It makes no difference whether the 43-plate variable con- denser is placed in the ground or aerial cir- cuit; both function the same. A variable plate-battery may increase the signal strength, but it will not give sharper tuning. » * * J notice in alt schematic diagrams that the secondary circuit is connected to the negative side of the A battery. Diagrams that I have received from the De Forest company con- ned the side to the positive pole. Which is correct? I also note that the phones are connected to the positive side of the B bat- tery. Con you explain this?— Paul Keller, Springfield, Mass. It makes very little difference with which side of the A battery you connect the sec- ondary circuit, but it seems to function best on the negative side. It makes no difference which side of the B battery the phones are connected in. * * * / have a home-made crystal set, an 80-foot aerial, and 2,000-ohm receivers. Sometimes I can hear the concerts clearly; but, at other times, nothing is audible excepting code. Is my circuit O. K.t Can you suggest any changes?— Russell Williams, Jacksonville, Flo. Your set is not connected in the most ef- ficient manner. Connect one end of the coil- winding to the ground lead, and, also to one end of the phone condenser. Connect the other side of the phone condenser to one side of your detector, and the other side of the detector to one side of the slides on the tun- ing coil. The other side of the tuning coil goes to the aerial lead. This circuit will prove more satisfactory. Of course the tele- phones must be connected across the phone condenser to make things audible. * * * Where can I buy "peanut tubes?" Can they be used in a regenerative set, using spider-web coils? What causes the re- generation in a plate variometer since there is no inductive relationship with the sec- ondary of the vario-coupler as with honey- comb coils?— James Cudahy, Williamsport, Pa. "Peanut tubes" may be used in any place where any detector-tube may be used. In the variometer type of a regenerative set, re- GENUINE WESTERN ELECTRIC V-T-l Detector and Amplifier $7.25 All tubes thoroughly tested and guaranteed. Finch Radio Mfg. Co.

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RADIO WORLD 27 generation does not depend on an inductive relationship bat does depend on simply tun- ing the prate circuit to exact reasonance with the grid circuit When the two circuits are in resonance, the high-frequency resistance is greatly lowered with the results that much more energy is allowed to circulate. * * * Who is WCG, 2 AKH, 2RMT What is the meaning, of QT AT— Samuel Lebowitz, New York City. WCG is the Bush Terminal station, 36th Street and Second Avenue, Brooklyn, New York; AKH is the station of D. Hopkins, 450 East Fourth Street, Brooklyn, New York; 2 RM is the station of F. A. Mayer, 828 55th Street, Brooklyn, New York. QTA means, "Kindly repeat your message." * * * Would four wires, 25 feet long, amount to the some and give the same results as one [OO-foot aerial f— Bob Moore, Brooklyn, New York. Using four 25-foot wires will not give you the same results as a hundred-foot aerial in one stretch. Change from the 25- foot aerial. Erect the hundred-foot aerial in one length. * * * / would like to see a diagram of a single- slide tuning coil showing the connection and shder.— Harold Kent, Kingston, New York. Slider-i Slide rod- Binding P of suit-le-slide tuning coil re- quested by Harold Kant, Kingston, N. Y. The above diagram shows a single-slide toning coil with a slide rod and two con- nection*. This is used in conjunction with the crystal detector. * * * On what schedule and wave doei the IfSf??** station operate f —Harry Leavy, Hillside, New York. The Anacostia radiophone station, Ana- costia, D. C, operates on two schedules a week, Wednesday and Friday. Both sched- ules are transmitted on 412 meters com- mencing at 8.30 p. m. Eastern standard time and ending about 10 p. m. * * * / am enclosing a circuit to which I would **e to add two stages of radio frequency ™° sta9es of audio frequency now in use. Please furnish wiring diagram as men- turned, recommending the transformers to be •ted. Tims ts a wonderful circuit, and, I beheve, second to none. As a detector, I have THz.y°^ff f™!* stations a thousand miles *stant.—tV. Miller, Dallas, Texas. Applying radio frequency would mean that a complete change of equipment and wiring would have to be done. Why employ radio frequency when you can hear we distance you mention? Probably radio c??"^ LwJ11 n0* tfve you this range. •J? toJ.wha* vou have and do not bother with radio frequency at present. * * * To receive continuous waves, do I need SWd tf be audible in the phone receiver rectifying the wave receivedr If not why t— Frank Paseta, Buffalo. xou cannot receive continuous waves with •crystal detector unless you have an ex- ternal heterodyne-system in order to make 1> 3fnala audib,e in telephone, "cannot be done with a vacuum tube un- you use a regenerative receiver with a ;n*« r ^J0™- 80 .to*5 receiver may be turned r~ a self-heterodyne. Heterodyne in this we Hearts, simply, a local source of down production which will create waves of radio- frequency either just below or just above the frequency of the incoming wave. The two waves will then clash or, in other words, be out of phase with each other 500 times .every second. This will produce an audible note, corresponding with the dots and dashes in your telephone receivers, of a frequency of 500 cycles per second. Inhrersal Phone Connector Can be used with any type mortar, stakes possible the use of four arts or phones. Elimin- ates energy loss. Heart Ij nlakel-plsted. sod gulx- sniesd to site romp Lets satisfaction. Price 75c a pair Dealer, Write for Liberal Discount, Universal Phone Connector Company Room 138. 1400 Braufstsy. New York Otty "METRO SOCKETS" MOULDED BASE for Westinj-hause Aeriotran I « 1 1% volt dry cell tube. This L. (M LVe^aatfl Sin»'° V ■ Socket-Bras, socket Is perfectly finished us- hBaVy nickeI ***** ing a V square hi«Uy pel- P^^__fl countersunk con- lsned moulded base. This base l^M *"Ct* M is supported with insulated H FIBRE BASE ^ mJ* Stat*. V. T. Socket ».7S t"ct- "** Laaaaaa. LaL. A TrfpU V- T- Soekat ZJS "METRO JACKS" No.1— Single Open , ease No. 2-Sincie Circuit m NaS-Double I! No. 4-3 Sprinc Filament Control !"!.'!"!" JS No. S— 5 Spring Filament Control m We alto make regular T. T. Socket, with fibre and moulded bate. METRO ELECTRIC MFG. CO., INC. 121 PRINCE STREET, NEW YORK ATTRACTIVE PROPOSITION FOR IOBBERS AND DEALERS. MICROSTAT VERNIER RHEOSTAT The most sensitive Moment control and quickest, easiest tuned. This microstat has ten times the possi- bility of exact filament adjusUnent as over the ordi- nary wire rheostat. It eliminates grating and interfering noises, has single knob adjustment and is far more durable being made of better material with greater care. This microstat takes up less room on the radio board, is neat and compact. The exact calibrations of the microstat are due to the gradual entering of two points into the resistance material of our own com- position which gives us exacting and most minute measurement of current to the filament as the oper- ator brings the two points together or separates them through the screw handle. Order through your dealer or /n» •« A f\ delivered to any part of U. 8. ^Jp JL •Tafcv/ MICROSTAT COMPANY WILLIAMSPORT, PA. Dealers, write for quantity prices WARNING TO OUR READERS! RADIO WORLD accepts subscriptions thru the American News Co. and its branches, the regular news trade and subscription agencies. No •then have any right to solicit or to accept payment for subscriptions unless they can show a properly signed subscription authorization from this publication. RADIO WORLD, 14* Brcdway, N. Y. C

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28 RADIO WORLD PATENT Tour Radio Meat, Ml * Write FREE ADVICE ALADDIN ELECTRIC COMPANY, INC COMPLETE RADIO SETS WRITE FOR PRICES. 71 WmI Broadway Now Tork Oty Every One On His Own Wave Length ITH the advent of cooler weather, which is to bring with it tremend- demands for radio broadcasting, Law Storage Battery Attnetwo O— tors' Discount* Writ* for Details WILLIAM LAW COMPANY Aborn and Sabin Stmts, PlWdeDOS, R. I. FOR SALE ATTENTION MANUFACTURERS and DEALERS— Complete set of tools and working parts for manufacturing a new crystal detector stand. Costs about 12 cents and sells for one dollar. Qood chance for you to get into the manufacturing business COLEMAN RADIO COMPANY 62 HIGH STREFT SPRINGFIELD. » c—Rocky Mountain Crystals— i •rmra than ■alma ■la* bs OMd with eas ex i staas* at KouatwL Set Unmounted, ISe-i Postfe*. Mionufacturtrs, Jobbers. Dtalrri, Clubs, Apth for Sbsciol Trod* Pncos Ricky Momrtam Radio Products, Ik. » CHURCH ST. NtW VORK. N. *•__ THE GOODMAN PATENT PENDING iMKiraw Short Wave Timor on tit. M-flaot Only SC-Ot A PP on 1 lb, for pamphlet. Ordor thraeifh your doalor. L. W. GOODMAN DREXEL HILL, PA. Dr. MUte. 1 CMesae, writes: "sO, irtAlMl and Terie-ooupler now to lata tb> Oswald." HOMCHARGE YOUR RADIO BATTERY Jor A Nick&l HP———— — ENJOYABLE Radio Conceits and M murium Receivin*. Rang- are obtained only when your battery is fully charged. Tbe charges your "A" or "B" battery over night. Silent and dean in operation— require* no watching — may be uied right in your bring room. Connects to any lamp socket. — cannot overcharge or injur* the battery. Entirely enclosed — approved by Underwriters. Uncondi- tionally GUARANTEED. Laiti a lifetime. Beautifully finished in Mahogany and Gold— the most efficient and handsome rectifier ever produced. Bulletin 637 proves it- send for your copy today - IT'S FREE. Sold by ail good dealer* or shipped prepaid for »18.M. complete. Deattrt-Jobbvn: The HOMCHARGER Merchandising Plan offers the best proposition in the entire radio field— send for details. THE AUTOMATIC ELECTRICAL DEVICES CO. lit W«> Third Str~t w UUS VI*. ...CIV. -J " , there is arising a certain amount of bit- ter feeling against the amateur who either is transmitting code or testing his home-made broadcasting station, says "The World," New York. In the larger cities these amateurs are becoming so numerous, and are in many cases so dis- regarding the government regulations re- garding wave lengths, that they rapidly are becoming hindrances to the thou- sands of persons who desire to listen to the programs being broadcasted by the larger and more efficient stations. Now there is no getting away from the fact that the amateurs have as much right to operate as have the broadcasting sta- tions; they have as much right to fulfil their desires for pleasure as have the owners of receiving sets, and have as much right to improve their work as have the more powerful plants. But it must be remembered by them that there are government regulations forbidding them operating on other than certain wave lengths and that when they violate these regulations the chances are they are in- fringing upon the pleasures of their neighbors. No one believes any of the amateurs who are preventing others en- joying concerts are doing so intention- ally, and it has been proven that a call on the air or on the wire phone will re- sult in the amateur either returning to his correct wave or standing by until after the close of the program with which he is interfering. V-, A C U u M T U B E R E P A I R I N G V jupalrtoi an *£•>•" "l^SSSrV^! a sbuto tunntm filamot aann «* o» Radlotiwa UV-SM. UV-IM. n-aOO. Q-Ml. A-C-U-U-M-T-U-B-E-R-E-P-A-I-R-I-N-G Save Ml 50 1 &T«0D ?.00 £ Detectors A | Amplifiers^ u u T U B E R E P A I R George H. Porell Co, law. I WOT SOMCRVILLE. MASS. N •A-C-U-U-M-T-U-B-E-R-E-P-A-I-R-I-N-G Deteeters and Asapllnere npaind 18.60. In* remind tabs*. w» warrant, win gift) iSS SSmSm antSaM satiifaet-n that — wan— arpoet to repairs tram paw ta pat. Wo an new in a BoaWaa to fir. «mr- ee tot prompt dauTcrloj rtSjf*^ tor/ "oalta.. A trial win Identifying Mark for WGY THOSE who have listened in recently on the programs of WGY, the Gen- eral Electric Company's radio-broadcast- ing station at Schenectady, New York, have observed a whistle between num- bers. Some fans have thought the whis- tle was due to an imperfection in their receiving outfits; others, observing that the whistle came only from WGY, were convinced that there was something wrong with the transmitting outfit. Neither theory is right. _ The whistle, or musical note, is caused by an audio-frequency oscillator used at the transmitting source for the con- venience of the audience. The oscillator comes into play by means of a relay which is operated when the studio switch is thrown off. The instant a musical number is ended in the studio, the whis- tle starts. ... .... This musical note, or whistle, will be- come characteristic of WGY— an identify- ing mark, if the audiences approve. If listeners-in dislike the device, it will be discontinued. Many people have re- ported that they have lost the station be- tween numbers, and before tuning m again the next number is well underway and they have failed to get the announce- ment. There is sometimes a slight delay between selections, a delay which seems minutes to the man at the receiving set though it is actually only seconds. He thinks he is out of tune and begins to re- tune. The musical note persisting dur- ing the intermission enables him to know whether he is still in tune with the station. Any single copy of Radio World, bo- ginning with No. 1, mailed on receipt of 15 cent* postpaid. Any seven issues for $1,00. Or send $3.00 for 0 months (20 num- bers) or $0.00 for 1 year (52 numbers) and have yonr subscription start from No. 1. Radio World, 1493 Broadway, Now York. The "COPPER GIANT" MB" Battery IS GUARANTEED FOR TWO YEARS In ANY reoelrtnf art. because it dot* not d rat* while standing Idle. This U a rery buttery designed for stationary or eetnl-pi Installation, where absolute reliability erer a led of yean la the first — roltagea — 21. 50 and 100. order. Write for lUuotraUooa. J. A. R1TTER, Recommended by Dealers tor ADIO STORES CORP. VARIABLE CONDENSERS- PLUGS— RESISTANCE UNITS, ETC. It your dealer dseea't eemr. address Dart. D. 222 West 34* Street, New Vera BUILD YOUR OWN Ooaplet* to*, tn.trortion nook lor tOe.only 'J^^^^n I on radio reception and hew to make right ^/M(7/t/ rlaesee of erystal and varutin tab* f\ /V 1 m,hlor Hll. VTonderfol Inform* I J I 1A k ljaet» a(lon n|kr| TOO nndf-raland radio. /il II , With every order wo fend fro* nrUUU pr|„ )ujt ol none prepared rip**lelly lor the s**eral »rte described. Hn v direct lro» fartory and eare many dollars. Both to- strnrtlon booh and prlee llfft eeoton reeelpt of SO*, only. Money back If not pleaaod. RADIO PARTS MFG. CO. Dept. 15. Part PI. W- Detrstt. mob. RADIO MAILING LISTS 9170 Retail Radio Dealers. United States Per M, ST.** 1184 Radio Manufacturers per list, 10.JJ 1S30 Radio Supply Jobbers per list. ll.S* 257 Radio manufacturers of com- plot* sets Per list, 4.»0 260 Radio Station* per Ust. 4.0* 14000 Radio Amateurs and Man- agers of Radio Stations... per M. 7.50 Neatly typewritten and ready to send yon en receipt of remittance eotering the amount. TRADE CrRCTI.AR ADDRESSING CO. 16* W ADAMS STREET CHICAGO, ILL. The Advice of An Expert THIS sign on the clean plate- glass window of a radio shop means that a competent radio expert is in charge within, who will gladly give you the benefit of his broad experience in selecting just the radio equipment to suit your purse and purpose. "it Pays to Buy at the Sortine Storm" Mr. Dealer: — If too are a proareeslee merchant. — sjew dlsplay tbe Sorstne sign. Let us tell you how. Snip Owners Radio Berries. 8* Washington Street jitized by VJW-" D1J'ribu"" Maw Tork

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RADIO WORLD 29 VARIOMETERS With our special winding you can pick up Pittsburgh, Kansas City, and many other points, they'll do the work or money back. OSL AND, ltt Fifth Are. INC. Haw Tart FIVE VOLUME $197 RADIO COURSE 1= laara Badle la year own doom. Ne leac ti Ike Are rotoansi of The Badle Boo/Sns. tor only II. 9T — will giro you a thorough ela canon Id radio at bona. Oat all the pk ood admaooaMot of tau fosotoatlni eoanee ami profte- eton. Know bow le baUd all klads at sola Oet started riant — tot started now— tot Uuo Course Bolted and Approved by Prof. J. M. Morwcroft of OohnabU UrArerattj. lake adtaaua* of thla MOW. The oonplete Course of floe - r only «.»*. iter/ Sond No Money £ SSL." STSJIS saaas end address end pay the ponmoa tl-*T and postoce. If yea ere not atoro then oatlaflod retara the Coarse In no* dare end wo win lmaoatetely refund your iieiay. START NOW I THE RADIO READING COURSE SB Seventh Ave, Dept. RW2, New York Ctty LEE RADIO CORPT-T. Haddenjfleld New Jen-way ANNOUNCES THEIR "B-I" SET (Patent Applfd Tor) NEEDS NO AERIAL PRICE, $35.00 Kxcept "A" Battery, Write for FTopeattlasL Come to Must sacrifice established WHOLESALE RADIO busi- ness. Controls exclusive sales agencies. Write Mr. Clay, 920 Chapman Bldg., Los Angeles, Cal. To the Man with an Idea I offer • comprehensive, experi- enced, efficient service for hie prompt, legal protection, and the development of his proposition. Send sketch or model and descrip- tion, for advice ae to coat, search through prior United State • patents, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable me to accurately advise clients as to probable patentability before they go to any expense. 'Booklet of folooblo Information, ood form for praportr dUrloelai your Idea, free on moat. Writs today. RICHARD B.OWEN.retest Lawyer It Owes BefldhKj. Wsoelettoe. O. a H7S-P WeeleertB Bid*.. Hew York Ofty RADIO WORLD rSUnKOTB. BBTAJfr 4fH BATTJBDAT 0» fUsTB WBBX) nOH VOBUOAXIOM OBBICB. UM BBOADWAT. ICBW TOBAw JC. T. BT BBrTKBBSTT BADIO BOLAXD BtTBBB BBMNBSST. WssdsM M. B. BBWWBBI1T. Tito Prootdoat FBBD B. OJUtM, ■■■otory ASSOCIATE Borroasi SUBSCRIPTION BATES, IWoooa ees* a oaay. ia.es a year. SS.M I n aasatke. S1.S0 fat tor Add ll.M a year setts far of annuo, priority of etahus. the I est of teoBafeel proktoooL or ethsr ■ saw See ndated la seed him end m -^mm* bb l ' " end ssattaoenw fa Fans Crowd to Hear Talk on Superregeneration IN all of the annals of amateur radio clubs, the most crowded meeting ever held by any of these clubs came off last Monday night at the meeting of the Radio Association of Greater New York, says "The Globe," New York. At this particular meeting, R. W. Tait gave a highly interesting talk and demonstration of his super-regenerative set. The meet- ing place was full to overflowing and it is understood that a hundred or more people were turned away. It is generally recognized that the broadcast listener is sadly in need of education, and the only way that this can be accomplished is through the radio clubs. The Radio Association of Greater New York has set the pace in this matter for the New York district and will, from time to time, arrange other talks of equal interest to every one who has a radio set The club in particular is affiliated with the American Radio Relay League and is also connected with the Second District Executive Radio Council. It has been in existence for several years and has a very large membership. This club is probably the only one that has a real dyed-in-the-wool lady operator for a sec- retary. This young lady, Miss Margue- rite M. Powers, has, we understand, a commercial license and is the proud owner and operator of a C. VV. trans- mitter, call letters 2BVX. If you are interested in radio you should investigate this live organization with the object of becoming a member. The dues are almost nothing, and a club set will undoubtedly be installed in the near future, all of the necessary appa- ratus having been donated, but no suit- able place for installation has as yet been secured the Radio Association of Greater New York numbers among its members some of the best known radio men and amateurs in New York City, and the beginner will probably be able to secure a valuable radio education by joining the club. Meetings are held ev- ery Mondav night on the top floor of th- ptiblic library at 535 West 179th street. DIfmUBtJTOM BOB ■TXYBB BBXX AFFABATOB EDWARD J. FRENCH 1U8 Park 8t. PwskaUlI, M. T. Dealer' t Prices Bent Cfceerfutay Complete Installations RADIO CITIZENS WE SATE YOU MONEY Send ox a list of your radio seeds for our prices. If Its Radio, ttv have it and we sett it for lets. JOHN R. KOCH COMPANY CHARLESTON WBST VIRGINIA FEDERAL $ n-W. 2200 OHM PHONES We era ill its I eat ear swot sad wBI asad ens YwaTw. Otty, wPSBBaf nsB*wteBBBBwB> VlS CTtanaaT. IwBBBaMsr* 5 J. H. 0% C 3. OP ELL COMPANY 4ST-4S* WIST «ZND STBBXT NEW YOU CITY CJTHENS TRUTONE RADIO HORN — LOUD SPEAKER It Is odd ea a i at set ■ ' - DittribeOert end Deelert, write I AUTO PARTS MFG. CO. IMS TruaaMy Avw, Doll oat. I Wnmt to Kotow Al Abo est A senile T Send 15 rants far a oeay sf B Ko. 11. daoad OOL T. ThU nootor oontoiae ea onlale ears, oloo. ud rtrle of serials II to InfonooUTO. praruaol, end It lo briar oad to tbo poiel It woo wruua ay C D. W erporc ADJO WOBXD. elowta BAOIB WBBLB. USS Biaeeway, ■ea York. ». v. Pictures and Facts About Armstrong Amplifier Radio World haa publtshsd a number of pictures, diagrams and deeerlpUve er- tlclee recording tho New Armotrong Bun- er-Reeeneretlve Amplifier. The nambesw containing* this material ere dated Jaaa It. July «. July It. August t and Sep- tember 1«. They will be sent postpaid on receipt of It cents each, the Sve oog- lre complete for 7$ coma. Or yon can oubocrlbo. f * 00 year: tl.OO. eta. m on the. end hovr Tour subscription atari with the number dated Juno J4. RADIO WORLD CO.. lit) Broadway. Nov ~ ^Tora.

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30 RADIO WORLD DO TOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT h A WORD RADIO WORLD S QUICK-ACTION CLASSIFIED ADS a* tee rata* ML Issadere so RAD mntm imn tent as, scary- rmM tar tM* The rata tar this RADIO WOULD > QU1CK-J U% far U >IO WORLD wfll ACTION RADIO WORLD CO, M thee r* pan as ree la RADIO WORLD am I AD. DEPTi fa tc (S Math*). Cbauaa Braadwar, N. Y. C. (I wary w taa day* i I fattfafa— at U were*, mada la ataaataw alaistnU ashre. If Olfa) HOOKUPS: Orer 100 blueprints to select from at 10c each. Send dollar for trial order. Radio Supply Co., Box 192, Pueblo, Cola PATENTS— Electrical caaea a specialty. Pre- war charge*. B. P. Fishburne, Registered Patent Lawyer, Sri McGiU Bldg., Waahiagton, D. C dvftaar RasnasnaSar* Roger* Ra Company, 5133 Woodworth Street, Pittsburgh, Pa. TO THE TRADE— Fixed Phone and Grid Coo- densers. Write tar price Hat aad sample. SALKEY RADIO CO.. tm Eighth Ave., New York CUy. FREE with each $15.00 Western Electric Head- set, one UV a» Detector tube. We handle every- thinr in Radio. NEWBURCH RADIO SHOP, So Broadway, New burgh. New York. An you familiar with all the radio symbols aaed in the rations hook-up* published in Radio World f If not, secure a copy of Radio World Nsl 36, dated Sept. 23. In this issue waa a coin* plete table of all important symbols uaed in radio construction and testing. Send 15 cents for a copy, or $£.00 per year, and have subscription start with that issue. RADIO WORLD, 1493 Broadway, New York City, N. Y. FIRST MONEY ORDER for $26.00 takes my iheinartr Tuner with bulb, socket, and Bradley- Sttt as described in Msrch, 1922, f'Q. S. T." W. HAIGH. 58 Newfield St., East Orange, N. J. ISSUES OF RADIO WORLD from April 1 to Oct. 7 (27 numbers) for 15c a copy, or the whole lot for $3.15. Or send us $6.00 for one year and start with the first number. RADIO WORLD, 1493 Broadway, New York. Exchange Jolly Interns tin* letters through our Club I Stamp appreciated. Betty Lee, Inc., 4254 Broadwsy, New York City. RADIO MAN, eleven years' experience in all sides of the game, capable of constructing, fa- stalling, operating broadcasting station of any power, desires permanent connection. Go any- where. What can you offer? Evans, Momus Pier 48, N. R.. N. Y. C. HELP WANTED— MALE EARN $11* to tat Monthly, expenses paid, as Railway Traffic Inspector. Position guaranteed after 3 months' spare time study or money re- funded. Excellent opportunities. Write for Free Booklet G-15L Stand. Business Training Inst, Buffalo, N. Y. CASH FOR OLD GOLD. Platinum, SOver, Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamp*. Falsa Teeth, Magneto Points, Jobs, Any Valuable*. Mail in today. Cash seat, return mail Good* returned fa ten days if you're not satisfied. OHIO SMELTING CO, 337 Hip- podrome Bldg., Cleveland, Ohio. NEWS AND GOSSIP OF THE STAGE— Send 10c for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.00 year, $2.00 six months, $1.00 three months. New York Star Co., 1493 Broadway, N. Y. BROADCASTING STATIONS: Letters and ad- dresses of broadcasting station to- date appeared in Radio World for Oct. 7. Sent on receipt of 15c Also a broadcasting map appeared in Radio World No. 8. Sent on receipt of 15c Radio World, 1493 Broadway, N. Y. City, N. Y. HIGH GRADE VARIABLE CONDENSERS at nearly cost of manufacture. Only 200 left. Sat- • isfaction guaranteed. Aluminum plates, braaa shafts, condensite panel enda. 23-plate, $1.45; 43, $1.95. Unassembled, 50c. less. Postage 15c. In- teresting proposition to dealers. WAGNER NOVELTY CO., Delphos, Ohio. IF YOU WANT AUTHENTIC RADIO FACTS consult "The Radio Telephone Handbook," by H. G. Cisin, Radio Engineer, former instructor Cor- nell, Stevens, John Hopkins; also former U. S. Naval Officer. Sent postpaid, $1.00. Allied Engi neering Institute, 1400 Broadway, New York. FREE— Write for free catalogue, giving attrac tive prices on standard radio products. Perfection Radio Corporation, 149 W. 23rd St, N. Y. City. DO YOU USE A CRYSTAL. DETECTOR T ARE YOU MAKING A CRYSTAL RECEIVER? In. crease the efficiency of your crystal detector L00O per cent by using a "FT" Ultra-Sens* tive Con- tact. Of special gauge and alloy; makes and holds a quick, ultra-sensitive, stable, adjustment. Endorsed by RADIO WORLD. Using galena, you may pound panel or table without disturbing sen' sitivity in slightest. Proved practical on ship board by an oldtime Marconi operator. Using a "PT" Contact on galena, Arlington (NAA) was brought in clear at 3-300 miles (below the Equa- tor); and Arlington came in loud at 2.200 miles (of Dutch Guiana). In both instances, nearby shine using vacuum tubas ware unable even to hear NAA. As to stability, Cape May (WCY) was worked over 1,000 esndlng right through crys- tal with Z KW spark, without affecting detector's adjustment. Replace your insensitive unstable spring or catwhisker wih a Contact which will hold its adjustment in addition to giving louder signals and music Indispensable for use in your crystal set, regardless of make. A novice can install. "PT" ULTRA-SENSITIVE DETECTOR CONTACT, with instructions, twenty-five cents, coin or M. O. "PT" CRYSTAL CONTACT CO., Box 1641, Boston 8. Massachusetts. FRENCH TUBES, genuine (no bootleg with French name), moat sensitive and economic. (Good for detectors, amplifiers, and especially for radio frequency. Will work very good on two dry cells.) Price $3.90. ATLANTIC & PACIFIC RADIO CO., 131 W. 37th St., near Bway., New Yrk. Will Trains Be Controlled by Radio ? ALTHOUGH it does not come di- rectly under the matter of train con- trol, radio train dispatching really comes under this classification, writes Raymond Francis Yates in "The Evening Mail," New York. As early as 1910, Earl Han- son, who is a very-well known radio in- ventor, was employed by the Santa Fe Railroad to perfect a system of this nature. Hanson rigged up aerials on the cabs of a number of locomotives, and the engineers were communicated with en route. Although very encouraging re- sults were obtained, the railroad officials are hard to please and the experiments were abandoned. With our modern radiophone equipment it would seem that there shouldn't be much of a problem to radio train-dispatching at the present time. The engineer at all times could be within listening distance. Numerous attempts have been made to establish direct telephonic communica- JUST OUT! 50 "VACUUM TUBE HOOK-UPS FOR RADIO RECEIVING CIRCUITS" Largest collection of V. T. Dim gram i »r plying to Radio Reception ever Publish under one cover. Contains Latest on Radio Frsquen Super- Rsfansrmtioa PRICE PREPAID fl.M W. A. DICKSO 44* E. Fort St. D» -■ nmrnra tion with engineers, but the systems used were impractical. If there is one great need that radio can fill, this would seem to be the one. If the engineer in the wreck had been given a warning mes- sage in time he could have brought his train to a stop, and a great disaster would have been avoided. Of course, if the man had fallen dead, and no one knows whether he did or not, all the speaking radio in the world would be of no avail. On an occasion like this, radio control would be the only thing that could be resorted to. In New York's subways there is a won- derful example of automatic control by a wire system. No more than one train is allowed in a block at a time. If the motorman of a second train passes a block signal, the emergency brakes are applied instantly and without effort on his part. While this system works beau- tifully in the subway, where the more delicate parts are not brought in direct contact with varying weather conditions, it would not hold up and perform the same services on an outside track. MULTIPOINT (Patont rontOn «) tic product sensitive over its a I.. ic-ior troubles. 50% Increase uid Tolumo. Endorsed • 50c. nd Distributors Quoted Attrael Irs Discounts ' N1TE PRODUCTS CORPORATION IS PARK ROW. NEW YORK STANDARD HEADSET tJM» OHM .VTL?^W*S!.r- $5.75 Sealers and jobbort write. Standard Electric Sales Co. Street Newark, N. >. KNOCKED- DOWN VARIABLE CONDENSER MONEY-SAVING PRICES i , .__ asafOv platsd. r ■ Knushsd st tbs fsUssnat low prisse Fists* Oaaasltr '"If II II 4* .oooo: .toots .0000 .001 Lett's Better Radio 47* ORAMSC STRICT n t.io ft.** •is it-so »*.(• it.** Condenser Co. NEWARK, ■. J. Superior Radio Products All Parts. Receiving- Sets Complete and in Units. Send (or Catalogue and Price*. Diattrt Writ! for Proposition RADIO OUTFITTING CORP. MfK BlsTb Grade MaMm AuMuvtna 41* East MthYt. NV» York! N. Y. » Wtoouccoooin thistle" lit Id. Trained mm needed S1.800 TO S6.000 - tfa**Uye»mcd.lwi!itrn>r, you quietly, ■ at home jn your spare time. to oonstiuuUnstaU I operate, repair, maintain and sell radio oat- litiz

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RADIO WORLD — and now harmony replaces discord! MUSIC— clear as a bell; speech- so that every word is marvelously distinct; jazz— in un- interrupted syncopation; opera— with that transcending:, full-toned quality which brings its remarkable beauty into strong: relief. This sort of radio reception is a matter of batter- ies. Elimination of most noises is a matter of batteries, rather than static or other interference. -\ These noises are caused by the irregular voltage output, natural in ordinary "B" batteries. Where the current output becomes unvarying, these noises cease— and this marvelously clear and life-like re- ception results. And it is because RADIOBATS "A" and "B" are the only batteries which act as radio batteries should, that we urge y ou to listen to a demon- stration at your dealer's. Until you have actually heard reception through RADIOBATS "A" and "B" you cannot imagine how wonderful radio can be — and there im noway to hear it till these epoch-making, new -principle batteries are hooked in. RADIOBATS "B" — as well as "A"— are leak- proof because they have the only solid elec- trolyte; and they are more economical, because, like "A" Batteries, they are indefinitely recharge- able at home. Send now for the intensely instructive booklet "The permanent Power Unit for Radio" and send your dealer's name and address so that we may arrange an immediate demonstration. There is absolutely no obligation. MULTIPLE STORAGE BATTERY CORPORATION J JO- A Madlton Avmur, N«w York I RADIOBATS Jhey>ermanentlladioyowen'UNIT Digitized by Google

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RADIO WORLD "MAKE PERFECTION YOUR SELECTION" TRIPLE COIL MOUNTING "Brings sounds from afar to right where you are." Made of Polished Bakelite with Patented Screw Adjustment. No. 303— Triple Price, $4.00 No. 302— Double " $3.00 No. 301— Single « 45c AMATEURS We Pay- Postage on Your Mail Orders. Write for free catalogue giving attractive prices on all standard makes. OWL RADIO FREQUENCY TRANSFORMER 150 to 500 Meters "Renowned for Sound" Tested in our laboratory. Will Work Exceptionally Well for Both Stages of Amplification. No. 495 Price, $2.25 PERFECTION RADIO CORPORATION OF AMERICA 149 West 23rd Street Manufacturers— Distributors New York City JUST OFF THE PRESS The most up»to»date Treatise on Radio dhook on Radio By JAMES R. CAMERON WboM textbooks are used and indorsed by the U. S. Army, Navy, end Department of Public Instruction 350 Pages. Profusely Illustrated. Written so the anuteur can understand it. At the same time— TEXTBOOK ON RADIO— is a st. idard textbook for the technical radio student. Order NOW and Be Sure of Your Copy! Cloth Bound, $2.50 :-: Flexible Leatho, $3.00 This new TEXTBOOK on RADIO is the new big brother to Radio's three best sellers "RADIO'S THREE BEST SELLERS!" HOW TO BUILD YOUR OWN RADIO SET, 25c RADIO DICTIONARY, 50c RADIO FOR BEGINNERS, $1.00 Bay Them From Your Dealer or Direct From TECHNICAL BOOK CO. 130 WEST 42nd STREET, Dept. W, NEW YORK Digitized by Google

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■vnal Radio Week October 28 15c. a Copy. $6-99£X*ar (See Page 7) (Trad* Mark) ILLUSTRATED. WEEKL Army Antenna Erected in 90 Seconds! * 9 * The recent reorganization plans of the National Guard of New York provide for the latest in radio equipment The above is an illustration of the type of low-visibility antenna used by the Signal Corps, Headquarters Com- " -hjit pany, 71st Infantry. The set is three feet high and can be erected in ninety seconds. This low antenna is specially ffng| adapted to the radio work of a battalion in a forward position. ZS (See story and additional photographs on page 1C) WHAT YOU NEED FOR AN ARMST^RONG^

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RADIO WORLD Most Complete — Interesting — Information Book Ever Compiled on Radio Whoee textbook* JUST OFF THE PRESS RADIO BOO" 350 PAGES ILLUSTRATED By JAMBS R. CAMERON used and Indorsed by the U. S. Army, Navy, and Department of Public Instruction Over four thousand mail orders received before this book was off the press. BUY FROM YOUR DEALER OR USE THIS ORDER BLANK ORDER BLANK TECHNICAL BOOK COMPANY, 130 West 42nd Street, Dept. W., New York. Please send me by return of post your 350-page, profusely illustrated Textbook on Radio, for which I am enclosing you Bound $2.50 □ Flexible I.eatho $3.00 □ Name Address Digitized by Google

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VOLUME TWO RADIO WORLD (Entered as second-class matter, March 28, 1922, at the Poet Office at New York, N. Y., under the act of March 3, 1879.} A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. Vol II, No. 5. Whole No. 31 October 28, 1922 15c per copy, $6.00 a year New Wonder of Warfare! Tanks Directed by Hidden Radio Operator THERE la no end of romance In the story at the r radiophone. It la an invention that in • big way after an Ignominious career. But such a wonderful thine as apealdna; and receiving through space, without wins, tubes, cables or other physical con- nections, was almost certain to fall into the hands el unscrupulous promoters, long before the serious, honest experimenters had an opportunity of evolving something more than a crude, laboratory demonstration. So wo And that, a dozen years ago, the radiophone waa nothing more than a crude device, making use of a sputtering, uncertain electric are as a "generator" of the high- frequency machine. The high-frequency, so uncertain as to bo almost hopeless, was module ted or varied by means of some form of carbon microphone. This instrument, aa anyone familiar with its construction knows, is quits ■moulted to the handling of heavy currents. A eeriee of experiments were being conducted for the United States Signal Corps with a view to proving the practicability of radiotelephony in military communica- tion. After numerous attempts the vacuum tube came into play. It opened a new era In telephone work. The vacuum tube la nothing short of an electrical acrobat. It can do all sorts of tricks— tricks no other electrical device has been able to perform. Today the vacuum tube la producing moot remarkable results, and the latest achievement in the United States Army is the equipment of steel clad "tanks'* by radio. With radio it la possible to direct war tonka to the direction they should got The photograph at the left Is the ulterior of a tank, showing the operator with his radio gear. The lower picture Is that of a number of tanks being directed by radio to operate in (Both photographs C. Pacific & Atlantic Photos. Inc.)

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RADIO WORLD A Simple Superregenerative Receiver By Harold S. Potter How the front manner. The two will look when completed. Too dials should appear on the panel In this dials to the right are the rheostats for the tubas; the three large dials are the tuning devices. Drawn by Harold S. Potter, SUPERREGENERATION is the carrying on of the familiar phenomena of regeneration, be- yond the point where it usually must cease, due to the circuit starting to oscillate, making the signals mushy and unintelligible. When the new system was first placed before the public, great claims were made for it, many of which have since proved unfounded. It was not, as was then claimed, the equal of the seven-tube superheterodyne, for long- distance, short-wave reception. How- ever, for short-wave reception over moderate distances, it is the thing. It is the solution of the apartment-house dweller's troubles, as it makes possible the reception of broadcast entertain- ments on a small-loop antenna without any outside connections whatever. Formerly this could only be accom- plished by the use of a considerable number of tubes, which meant a con- siderable outlay, but now it may be ac- complished with but two tubes. Superregenerative sets have been built using one, two and three tubes. The one which I am about to describe is of the two-tube type and best for general use. Many amateurs are under the im- pression that the superregenerative system is an expensive one to use. This is incorrect, as may be seen by the following list of parts and their cost : 1 bakelite panel 7x18x3/16 inch.. $3.00 1 wood base 9xl8x& inch 50 1 43-plate variable condenser 4.S0 1 23-plate variable condenser 3.7S 2 tube sockets 2.00 2 rheostats 2.00 1 D. L. 1500 coil (unmounted) . . . 2.75 1 D. L. 1250 coil (unmounted) . . . 2.25 1 3'/2 inch rotor 50 1 length cord tubing 10 3 3-inch dials 3.00 1 1-inch radius panel switch 50 12 binding posts 60 1 phone condenser 30 Wire, brass, screws, etc 50 Total $26.25 The panel may be of bakelite, formica, celeron or hard rubber; but hard rubber is not to be recommended, as it is apt to warp. It may be pur- chased cut to size and squared up. The dimensions are 7 x 18 x 3-16 inches. Figure 2 shows the details of the panel layout. If any other make of instrument is mounted on the panel in the place of those listed, allowance must be made for their different di- mensions. The holes should first be located by the use of square and ruler, then spotted with a center punch. The panel should be given a coarse- grain finish by rubbing lengthwise with a piece of No. 2 emery cloth un- til all shine is removed. A small quan- tity of olive oil should then be rubbed into the panel. A rich gloss finish will result. Closely allied to the panel is the base, which is of J^-inch hardwood, 9 x 18 inches. Three screws pass through countersunk holes at the bottom of the panel, into the front edge of this base, holding them firmly together at right angles to one another. This base is used for mounting the duo-lateral coils, the tube bases, the battery-con- nection strip and the tickler bearing. Two variable condensers are mounted near the center of the panel. Referring to Figure 3, C is a .0005 mfd. condenser used across the in- ductance to tune the input. See Figure 5» C2 is a .001 mfd. condenser used across the D-L. 1,500 coil. It should be shunted by a .001 fixed condenser, giving an effective capacity of .002 mfd. The input tuning inductance and the 18" 2i' r 3f *Z6 o 9 a o Y /7o* ±1 t L View of the front panel, showing all necessary dimensions for the construction of this superrece'ver. Careful attention should be given to section Suggested by Harold S. Potter. Drawn by S. Newman. , Digitized, by Google

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RADIO WORLD 5 Into tha nedvir. This U tha "layout" of tha aquipsMst, couplar and honeycomb cods. It (Continued from preceding page.) tickler are mounted together in the form of a vario-coupler, the tuning in- ductance being the fixed member. The form for this inductance is a piece of cardboard tubing 4 inches in diameter and 4 inches long. Starting an inch from the top end, wind for 2 inches with No. 24 D.C.C. magnet- wire, tapping every inch, giving 5 tap leads in all, including the start and finish. These taps are connected to the points of the tap switch, shown in Figure 1, below and between the cou- pler and condenser dials. A hole is drilled through one side of this tube, inch down from the top, and another 3jHs inches below it, to match the two holes in the panel, and are used for mounting. Two }i inch 6/32 flat-head nickel-plated ma- chine screws serve to support the in- ductance. A couple of battery ter- minla nuts slipped over the screws serve to keep the inductance % of an inch from the panel. The tickler is made by winding a 3yi inch rotor ball with a single layer of No. 28 S.C.C. magnet wire, giving about 96 turns in all. A % inch brass shaft passes through this ball and is supported by a brass angle bracket at one end, while a 14 inch hole in the panel, shown in Figure 2, serves as the other bearing. Great care should be taken in mounting and making the brass angle support to get the hole to line up properly with the not tha position of tha rarious btti noimii aach mm tha i Itt coaaptata toaaala— Draws by Harold 3. -attar, bearing hole in the panel, as otherwise the dial will not run true. In making connections to this tickler winding use flexible leads in order to allow the ball to run smoothly. In the variation frequency-generator circuit 2 large honeycomb coils are used. One is a D.-L. 1500 coil, in the grid circuit. This is shunted by the variable condenser previously men- tioned. It is mounted back of the tube bases, as shown at L3, Figure 3. A D.-L. 1250 coil,'L4, is connected in the plate circuit, Figure 5. In Figure 3 is shown the correct relative positions for these inductances, 3 inches apart at their nearest points, and at an angle of 60 degrees to one another. This I found to be the best position in my set, and slightly dif- ferent coupling may work best on an- other set ; but once they are placed the inductances need not be moved. Fig- ure 4 shows the details of the coil mountings. The brass support is made of strip brass ]/2 inch wide and 1/16 inch thick. The dimensions are shown in the detail drawing. A hardwood plug should he fitted to the center of each coil. But one screw is used to fasten each support to the base, so the angle of the coils may be changed, if neeel be, by simply loosening this screw. A most important part of any tube set is the rheostat. The tubes in my set are mounted at the lower right-hand end of the panel, below the peepholes. lust back of the rheostat arc the tube sockets. These are all bakelite. It is well to remember, when picking a tube socket, to get one which holds the tube snugly and has strong con- tact-springs, in order that a good con- tact with the prongs on the tube may be assured. A mica phone condenser having a capacity of .0025 mfd. is shunted across the phone binding posts at the lower right-hand corner. It may be seen in Figure 3 (C,). It is sup- ported in place by the wires which connect to it At the right-hand end of the base. Figure 3, is a strip of bakelite inch by 6y2 inches by 3/16 inch thick. On this connection panel 8 small binding- posts are mounted, to make connection to the A, B, and C batteries. These posts are placed }i inch apart. Two ;Vj-inch roundhead brass wood screws secure the connection panel to the base, while two battery terminal nuts slipped over the screws between the panel and the base keep it raised % inch above the base, making room for connecting to the binding posts. Regarding the dials, any 3-inch ISO- degree dial having a J4-inch shaft- hole may be used. When buying dials be sure to pick ones which are flat and true if even, smooth-running of controls is desired. Also, be sure to get bakelite dials — not those made from molded "mud" composition, {Continued on following page.) Digitized by Google

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6 RADIO WORLD which have a habit of chipping and splitting. The handiest binding post to use is the type having a hole drilled through for die wire or phone tip and a set screw. For the sake of appearance, get a small nickel-plated post, not a clumsy brass one. Only the antenna, ground, and phone posts are on the panel. All battery connections are made to the well to enclose the set in a cabinet. If you are not handy with tools this should be purchased ready-made. For those who care to build their own the following particulars are given. The inside dimensions of the cabinet are: 7 inches high, 18 inches long, and 9 3/16 inches deep. Quarter- inch oak, mahogany, or some other hard wood may be used and finished in any manner desired. The top of The honeycomb er duo- Lateral colls. This dlafram shows how they should bo mounted. Not* tfas position of their layout. Dimensions are givon to assemble them. Drawn by Harold S. Potter. Schematic dlacram of the internal wiring of the complete set. When wiring, it is beet to • all connections that can be soldered. Follow each connection closely ae you go along, one wrong connection will make Ae set inoperative. the wiring. Drawn by Harold S, Potter. connection panel back of the main panel. Next comes the wiring. The neat- est thing for this purpose is square, tinned-copper wire. If this is not available, No. 14 bare copper wire may be used. In order to make a neat job bend and fit each connection be- fore putting it in place. Make all connections short and avoid long par- allel wires, as these tend to produce howling and cause energy losses. Solder all connections. Be sure to follow the wiring dia- gram in Figure 5 carefully, as all con- nections must be correct if results are to be obtained. Carelessness may mean a couple of burnt-out tubes, so it is better to be certain than sorry. In order to protect the instrument from dust, dirt, and injury, it will be the cabinet should be hinged to allow for easy inserting and removing of the tubes, and for changing connec- tions. The battery wires should be led in through holes in the side of the cabinet. A 6-volt, 80 to 100 ampere-hour storage battery will be needed to light the filaments. For the plate battery, several B- battery blocks of 22JS or 45 volts should be connected in series to give the proper voltage. The grid, or C batteries, consist of several flashlight cells in series. The necessary voltage may vary from 5 to 25 volts, depending on the tube used and on the plate voltage. I found that 10 volts worked best on my set. A super-regenerative set cannot be used on a regular outdoor antenna ex- cept under -almost perfect atmospheric conditions. However, interfering noises may be eliminated by using a loop antenna. I use a loop 3 feet square, wound with 10 turns of No. 18 bare copper wire spaced an inch apart. Fine results may be obtained on a loop as small as 1 foot square ; in fact, little difference in signal strength will be noticed when changing antennae. About 50 feet of annunciator wire may be wound into a loose coil and dumped on the floor, the ends con- nected to the set. Surprisingly good results will be obtained. It is almost impossible to give in- structions for the operation of this re- ceiver. Adjustment of L2 and of C2 cuts out the howling and .whistling which is common to this circuit when out of adjustment. The various sta- tions are tuned in by varying CI and the tap switch. The final adjustments are then made with the rheostats and with C2. The above hints will prove helpful, but the builder must learn the meaning of the many indescribable sounds characteristic of this circuit. A little practice will mean more than pages of instructions. In conclusion, this offers a great field for experiment to the dabbler in superregeneration, as the circuits yet developed have their limitations and there is much improvement to be hoped for in the reception of spark signals over long distances by this system. And now, you "bugs" who try this set or are experimenting with super- regeneration : How about a line or two telling of your results? I would be glad to hear from anyone on this subject. Claims Receiving Record If Any Radioist Can Beat Mr. Merk- lein's or Would Like His Hook-up, Write Him. Editor, Radio World: Speaking of receiving broadcasting a la D X, I be- lieve I hold the record. On the night of October 16, at 11:15, I happened to tune out WJZ, and tuned in WDAP. Later I received WSB. Station WDAP is lo- cated in Chicago ; WSB in Atlanta, Ga. The concerts came in very clear, and only on one tube. My outfit is of the two- variometer type, and the design of wiring is my own: Two Steps of Audio, frequency— W 201— detector ; VTI— first step; VT2— second step; 110 volts on amplifiers ; 4 wire "L" type aerial, 40 feet long and SO • feet high.— Best 73, J. A. Merklein, 7S13 Third Ave., Brooklyn, N. Y. Perfection at Last Madge : "Do you know anything about this radio fad?" Marjorie : "It must be just lovely, dear. I understand that you can listen in." —"The Sun," New York. Fifty-two isooee for Se.Oo. Sab. De- partment, Radio World, 1493 Broadway, N. Y. " Digitized by ^Google

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RADIO WORLD I 7 Takes Radio Circles by Storm National Radio Week Acclaimed by All Radio World's Proposition, That Seven Days Be Given Up to Boosting Radio, Strikes Ten with the Trade, Fans, and Amateurs LAST week's issue of RADIO WORLD (No. tt, October 21) bad no sooner reached the newsstands and subscribers than the editors realized that it had landed as a bombshell hi radio circles. Telephone calls, messages, and letters soon made it apparent that RADIO WORLD'S announcement that November 2t to December 2 be set aside as a National Radio Week— to create greater public interest in radio, to increase the output of manufacturers, to increase sales by distributors and dealers, to create a wider interest among fans— is about the biggest thing that has hit the radio game since it was started. It so happened that a luncheon in the interests of radio was held at the Bankers Club, New York, the day preceding this announcement. This luncheon was attended by Hon. Frank H. Hitchcock, J. H. Beyers, H. Gernsback, Laurence A. Nixon, and ether men interested in radio promotion. When RADIO WORLD'S proposition was announced, it was so generally regarded as a matter of vital importance to every person and firm interested in radio, that the editor of RADIO WORLD hnasediately agreed to permit his suggestion to become a general plan of the radio world at large and to permit a committee to decide on the best and most advantageous time for the celebra- tion of National Radio Week. Consequently, a second meeting will be held Tuesday, October 24 (this page is going into type on October IS), when the prop- osition will be discussed at length and the final date decided on. The full report of this meeting will be published in the nest issue of RADIO WORLD. The first letter to be received by RADIO WORLD commend- h| its plan was from Edward M. Morgan, postmaster of New York City. His and other letters follow i e * a Laurence A. Nixon, managing editor, says "The Radio Dealer" says if s "smashing goad I " A —■him good Ideal It will create • grosnM interest la radio, team hiiehms, and brine now enthusiasts into our told. ♦ * • Edward M. Morgan, postmaster of New York City, an ardent Co- operator: As to As proportion that ttere te a National Radio Weak, there is ne duuht in my mtnd but it would te most useful; far it would unqass- llisililj promote the science and Industry of radio; sad whatever doss this will te for the welfare of the nation, since every advanes that fecBHates the conanunkanon of Information and Intelligence mates far cangntenment end progress. It would hav* a special atOity te tte poet office at tha time euggestod, November II to December 2, sines e e e H. Gernsback, editor, "Radio News," one of the first to commend the idea, writes: Anew the writer te compliment you on the idea of a National Radio Woeek. This Is a splendid idea, and if enough publicity matter can te broadcast as that tha nubile wul became aware that there Is such a movement, we are certain that It can only help tte entire radio In- dustry. Personally, the writer thinks that tte last week la December would, perhaps, te most appropriate, because It has been found, in peat yean, that there Is more interest la Radio displayed Just before sad after Clulslniso una during any ether time of the year. e e e Kendall Banning, editor, "Popular Radio," is with us: I am glad of the oeortunity net only of endorsing but of actively par- ticipating in any movement that will help te establish the radio Industry la the high position which It must eventually attain, Your suggestion for e National Radio Weak te a step in that direction, and I shall te glad to do what I can to mate It a success. » • » Paul V. Godley, famous radio engineer of the Adams Morgan Company, New Jersey, says: it will result in good: I see ne reason why such an arrangement as a National Radio Week should not result in earns good being dona. I must confess at this time, however, that no loess of value occur to me ia connection with your plan, although I shell watch its effect with interest. e e e What have YOU to say or suggest? What can YOU do to boost National Radio week in your town? What phut can YOU devise for some novel form of radio entertainment or display. Can YOU get up a radio party that will be pleasant and profitable and introduce strangers to radio? Suggestions forwarded to RADIO WORLD on this important event will be welcome and will be afforded space in our editorial columns. But— don't miss next week's RADIO WORLD. (Dated No- vember 4, on sale November 1.) It will contain the very latest and most important news regarding National Radio Week. Be a National Radio Week Booster Latest Important Radio News of the Week *¥*HE oncrocs of a eteteeo-hour test of electron * tubes hi piece of large sltemstors in trans- eatttrag wiretese tslsgrsph messages across the Atlantic from tte Radio Corporation plant st Reeky Point, L. I, has led Dr. E. F. W. Alexan- 'itef engineer of the corporation, and In- of the sltemstors which win soon te sup- by tte tubes, to predict that tte trans- of power from Niagara to New York through tha sir by men of tubes was s poasi- ftttty of the future. • • • It te reported that the Prince of Wales has be- eene an ardent radiotet and has induced his ; King George V, to Install a set m St. nccslpt of wireless mossogss melds a etssl car of a fast-moving train with no outside serial was eaommfuuy demonstrated by the Pennsylvania RaOrosd on the Broadway Limited, from New York to Chicago. Tha tests wore conducted by Amo ZUlger, of Philadelphia. The aerial need was an inside loop device, small sad compact, and placed on a table It was II inches square. The radio eat was assembled after the train left New York, etirou t» to Chicago, snd Immediately was tuned Into WOR, Newark. The entire concert was beard during the run to Philadelphia, where a second one was picked up. Broadcasting, even from the Great Lakes, was picked up all tte way to Chicsgo. see A charge that tte Radio Corporation of Amer- ica, the General Electric Compeny and otters have entered a conspiracy to obtsin a monopoly of wireless service snd prevent individual use of the radio ie made In a suit Aled in the United States District Court today by John O. Yeiser, Jr, of Omaha, Nebraska, who asks sn Injunction to restrain the defendants from interfering with hie right to broadcast. He alleges that hie own radio atstton wes dosed recently because he was operating slightly above the SM- meter wave length, snd mat tha first entendmeet to tte Can- ' etitntlea, which eayst "Congress shell nuke as law abridging the freedom of speech or of ths prose," is being thereby violated. A jury to de- termine damages, which he alleges to be tTMW, is requested, with treble damages under the Sher- man anti-trust law snd an attorney's fee of $2S,MS. • • • The KnoxriDe, Ti conjunction with tte other broadcast nightly tte i si] stolen automooilee. clubs of the state, ' Chicago newspapers report mat half tte sum once of the recent Radio Show in that efty wes composed of boys snd young men, and that the attendance was at tha Ho Chamber of tte National Radio ' experts save ths youngsters advice aa to what was wrong with their instruments. Digitized by Google

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8 RADIO WORLD Radio Legislation Slated for December By Washington R. Service CONGRESSMAN WHITE, of Maine, "father" of the Radio Bill calculated to improve radio in this country commercially, in broad- casting, and for amateurs, has re- turned to the Capitol and believes that the bill will be taken up by his com- mittee early in December. The enactment of this long-looked- for legislation will benefit all branches of radio, but officials of the Depart- ment of Commerce say that it will not entirely eliminate interference in' broadcasting. There are some fea- tures in connection with radio which cannot be corrected by legislation, it is pointed out by experts of the gov- ernment, such as the mastering of one's own set. Good Set* Badly Tuned Even if there were enough waves to give each station an exclusive band — and there are not nearly enough- interference would still be encoun- tered, or at least reported, by fans endeavoring to receive the news and entertainment offered by 522 stations, many of them in one community. This would be so because many receiving sets are not capable of fine adjustment and cannot be properly tuned to a specified wave length. Though possessing excellent sets, many enthusiasts are not able to tune properly; they do not know how to manipulate their sets and eliminate in- terference within a prescribed band. Already reports have been received by the Department of Commerce that broadcasting on the new 400-meter wave is interfering with that on the 360-wave, which should not be the case with 40 meters between. If transmission is good, first-class receiving sets should be capable of tuning within a variation of from 5 to 10 meters, inspectors say, unless one station broadcasting is in the imme- diate vicinity of the receiver. Although Secretary Hoover will probably receive authority in the radio bill to limit the number of transmit- ting stations, it will be difficult to ac- complish this in congested areas where several broadcasting stations are al- ready located. Municipal authorities and organizations of listeners-in may have to aid the Secretary, when the time comes, by indicating which sta- tions are the best and what services are most desired. The listeners-in are organized in Washington and such a body might become a censor of the air, so to speak, endorsing satisfactory sta- tions and reporting those which are unsatisfactory, thus aiding in estab- lishing better service. In any event, it is hoped that both wave lengths and time schedules will aid the broadcast- ing in congested districts. Must Learn How to Receive Distributors of radio equipment ca- pable of fine adjustment should in- struct purchasers carefully and, when possible, assist them in setting up their sets and tuning in. It is evident that a large percentage of those interested in radio must be educated in the use of their sets, and this may develop on the broadcasters who are interested in having their programs clearly heard or on radio associations. The Bureau of Standards has been giving informa- tion along this line for some time. It is expected by Department of Commerce experts that the loop re- ceiver, possessing directional qualities, will aid in the selection of broadcasts and help in eliminating the other sta- tions' programs, when used in con- junction with tube receiving sets. The cost is not excessive in comparison to an aerial, and as the indoor coil can be installed in a corner of a room, the disfiguring overhead aerial may event- ually disappear from housetops. It is part of the question of experimenta- tion and education in radio. How Radio Is Supplementing the Ticker in Wall Street THE amplifier U responsible for many radio achieve- ments. For Instance, the recent "spanning" of the Atlantic using 1 kilowatt of power, or less, would have been impossible had it not been for the highly efficient receiving equipment and amplifier employed. An ordinary set would not respond to such signals, and the transmitters, under such circumstances, would be incapable of forcing sound over so great a distance. Yet with the proper receiving set and su- per amplifier the signals from such a weak station were found to span the intervening space with a marked degree of success. This serves to prove that no matter how weak a transmitter may be, its waves are driven through apace and kept going farther and farther— endlessly. The advantage of employing a radio-frequency ampli- fier is this: It amplifies only the wave and not the many little irregularities and imperfections which ex- ist in the usual receiver and amplifier equipments. No matter how many steps of radio frequency may be piled up to aid the detector, the signal which has failed to actuate the detector will NOT be heard. With radio-frequency amplification, on the other hand, there is no critical point, and even the weakest signal is built up to the desired degree before it is passed on to the detector, there to be rectified to audio-fre- quency current, which, if desired, may be passed on through one or more stages of audio- frequency ampli- fication. The illustration at the right shows a self-contained, six-stage radio-frequency receiver which provided the thousands who flock daily into that short, yet long, thoroughfare known as Wall Street, N. Y., with news of the moment. It was an experiment, but it worked out 'wonderfully. The radio set is mounted on an au- tomobile, a It- inch loop aerial providing the neces- sary completion of the^ circuit. The broadcast matter was carried to the crowd by means of the loud-speak- er mounted on the shed of the car. (C International News-Reel) Digitized by Google

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RADIO WORLD 9 Radio Guides Rescuers to Steamer Burning in Mid-Pacific By Peter Gray FOUNDED IKI And foxl- 01 the !n TI.e th: .•*!•» 4 be ■cluav alien of in lain U an* ••III* Friday. October 13 1922 H« Mraftm. Vfovernutf the application si ike Voletead law le American and loreifn •hi pa Radio Saved 217 After Ship Burned Navy Vessels, Yachts. Lin- ers, Picked Up City of Honolulu's Calls West Faralon Reached Blaung Ship 4 Hour* After Her Com- pany Had Taken to Boats coupl tree on S elayl It thort upon they theor contra forma carefu stated of ihf cover, A A wit * wae No* Hay* Bchm chart my ikt aMadaM rum 8am Fiukcwco October 11 — Th« r« o-io man a bridle on apace, and that liardre less potent thing the fellow •hip 01 iaom who *o down 10 the a t"" stan." -m responsible to-da * jh raon V How tie "New York Erwaina; Poat" "peered mt ita story of the "Qty ad WHILE she was 670 miles off San Pedro, California, fire broke out in the second-class cabin of the giant ocean liner of the Los Angeles Steamship Company's new Honolulu service, the "City of Honolulu," once a pride of the North German Lloyd. In some unaccount- able way, the flames so advanced on the crew — which did heroic work fn battling them — that in two hours it was found necessary to abandon ship. But before that command had been given by Captain R. H. Lester the vessel's radio had sent far and wide the call that means disaster, distress, and the possible loss of human life on the high seas. Two ships, "Enterprise," of the Matson Line, and "Thomas," a United States Army transport, westbound, from Hawaii, picked up the signal and turned towards the position the oper- ator had given. A pleasure yacht, the "Casiana," cruising to Honolulu, with her owner, E. L. Doheny and party of friends aboard, caught the appeal and turned her bow that way. Los Angeles caught the signals and Navy vessels stood by to race with death to the scene of the fire. San Francisco caught the signals, waited awhile until the radio operator on a distant ship had turned that ves- sel, too, towards the scene. It was that ship, the "West Faralon," M. M. Walk, master, that swept down the sea lanes to the "City of Honolulu" and effected the rescue. But she did not get there until more than four hours after the flames had forced the captain, his first officer, the chief engineer, and the radio operator, who had stayed behind to serve to the uttermost the passengers confided to their care, to leave the blazing hulk. The officers stayed to advise, suggest, and confer; the radio operator stayed to keep the "West Faralon" advised lest she miss the boatloads of passen- gers floating near by and the rescue be delayed. The chief radio operator of the "City of Honolulu" was W. H. Bell, of Oakland, California, who was mak- ing his first trip. The assistant oper- ators were H. D. Hancock, Venice, California, and N. C. Kumler, Yaki- ma, Washington. The three men re- mained at their posts so long as it was humanly possible. Mr. Bell is twenty- four years old. Commenting editorially on the suc- cessful . and remarkable part radio played in saving the lives of the pas- sengers and crew in this latest of sea horrors, "The Times," New York, says: Fortunately there was time to lower the boats and get everybody into them but the chief officers and the radio oper- ators, whose duty it is to leave last and only when they are driven from their posts. There must have been anxious mo- ments for those in the boats, calm as the sea was. No smoke, no sail in sight Many women and some children were among the passengers. Those vast wa- ters appalled them. If help did not come soon, all knew the boats would not ride out a heavy sea. The comfort was in the thought that immediate response would be made to the radio signals — the nearest ship would come to the rescue under forced draft Even so, it might be a race between her and the winds of the Pacific that at this time of the year some- times rage on the briefest notice. But four ships, including the army transport 'Thomas/ picked up the call. It was the good luck of the freighter. "West Faralon," to be only fifty miles from the flaming ship and the waiting boats. She was perhaps four hours getting to the scene. Quick work was made in taking the castaways aboard. Sailors never spare themselves when a rescue is to be made. In the old days of shipwreck without benefit of radio a rescuing vessel would probably have had to continue on her voyage to her first port of destination with the salvaged on board, but now there can be an interchange of messages between shore and ship. So it was ar- ranged to have the "West Faralon'' transfer the saved from the "City of Honolulu" to the army transport per- mitting the freighter to proceed to the. Dutch East Indies. As usual, the offi- cers and radio operators of the aban- doned vessel behaved with a gallantry and coolness expected of Americans be- set by danger at sea. When the battle with the flames was lost the operator sent out his "Good-by" nonchalantly, and down into the boat he went with the captain bringing up the rear of the little party. The story is one to stir human emo- tions to the utmost — to make mankind thankful that radio is playing so im- portant a part in the affairs of the world. Vacuum Type of Arrester Safe THROUGH proper publicity, the fear of danger in connection with radio sets has been greatly alleviated; indeed, to such an extent that some people have become exceedingly care- less in rigging up their aerial and ground systems. Some believe that by simply disconnecting the aerial and let- ting it hang free they are assured of perfect protection. Though it is im- probable that any damage would be done, this procedure is the least safe of all. Other people disconnect the aerial wire from their instruments and connect it to the ground lead. This is a safe but inconvenient method. One might forget to disconnect, with the result that some part of the set may be damaged. The best method to pursue is to per- manently connect some sort of light- ning arrester — such as a vacuum, or air, gap — in the circuit between the aerial and ground. With such an ar- rangement, it is not necessary to change any connections during a storm or to think of grounding the aerial. Two metal plates mounted on an in- sulating base, so that the points are about ii inch apart, will provide am- ple protection and be easy to make. There are a number of worth-while types of arresters on the market. Pro- vide yourself with one and be abso- lutely safe. The lightning arrester forms a positive protection against lightning troubles and will operate in- definitely without attention. Digitized by Google

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly ABC of Radio Facts and Princtples Fully and Tersely Explained By Lynn Brooks Tf 7HAT are the essential features ymf of construction of the audio- frequency amplifying trans- formerf The audio-frequency amplifying transformer consists of an iron core, around which are wound several thou- sand turns of fine insulated wires. The windings are in two parts — pri- mary and secondary. * * ♦ What is meant by primary and sec- ondary f The words are used to designate the two windings of the transformers. The primary winding is the winding into which the current is fed. It is generally marked on transformers by the letter P. It may be determined also by looking at the transformer. The smaller winding of the two is generally the primary, while the larg- er is the secondary. The secondary winding is marked S. It is the wind- ing from which the transformed cur- rent is taken. * * * What is the iron core made off The iron core is made up of a large number of thin sheets of a special iron arranged in a square, or rectangle, thus forming a complete path for the magnetic force which is produced in the iron when the transformer is con- nected into the circuit of any radio- receiving-set. * * * What is the function of these trans- formers? To change the audio-frequency va- riations in the plate circuit of the de- tector tube into the similar but greater variations in the grid circuit of the first amplifier tube. As a potential on the grid determines the strength of tht- signals heard by means of the phones in the plate circuit, the transformers make it possible to greatly strengthen these signals by increasing, or boost- ing, the potential impressed from the plate circuit of one tube onto the grid of the next. * * * What is meant by amplification? Amplification means to magnify or enlarge. In radio it refers to the mag- nification of tK" strength, or loudness, of the si - ved and detected. The transformers just described are used in radio as magnifiers. * ♦ * How are the radio signals amplified? By the use of additional vacuum tubes and amplifying transformers. In- stead of inserting the head phones in the output, or plate circuit, of the detector tube, the currents in this cir- cuit are passed into a special trans- former called the amplifying trans- former. After passing through the transformer the signals are conducted to the grid of an amplifying tube. Being of a greater potential when they enter the tube through the grid, these currents liberate a large plate-current. Thus, if the head phones instead of being inserted in the detector plate- circuit are inserted in the amplifier plate-circuit, the signals heard will be many times louder. * * * How many times may detected sig- nals be amplified? Experimentally, without limit ; prac- tically, the strengthening of the signals is limited to two amplifying tubes. * * * Can amplifiers be used with regen- erative sets? Yes; but it will be found advan- tageous to insert a small bypass con- denser around the primary winding of the first transformer. * * * What is the reason for this con- denser? The high-frequency resistance, or impedance, of the transformer wind- ing is so great as to form a barrier against the passage of the retuned cur- rents. A condenser allows the high frequency, or — as they are more often called — radio-frequency currents, to pass around to the grid without en- countering this barrier. Take Care of Your Phones One thing that is important — drop- ping phones. This is apt to break the ear-caps and possibly injure the wind- ings. It may injure the phones en- tirely. Receivers are built like a watch and should be given as careful atten- tion. Take care of your phones and they will last you a long time. How Crystals Change the Speed of Radio Waves Thousands of radio beginners have coma Into the radio field alnce summer. They will Sad "The Radio Primer." published weekly la RADIO WORLD, a regular source of Instruc- tion and aid. For this reason, RADIO WORLD will republish, from time to time, seme of the valuable primer articles that appeared la Its early Issuea These articles, by experts, con- tain a Test amount of radio Information that cannot be duplicated. Every beginner will Had them necessary to the building of sets and cooperative with the new material being printed. BECAUSE of a peculiar property which they have of letting only part of an electric current pass through them all radio waves, when they pass through the air. are in the form of a wave, one- half of which is traveling in a positive direction while the other half is travel- ing in a negative direction, said a writer for this department in Radio World No. 6. This is illustrated in Figure 1. Now a crystal of one of the substances men- Figure 1. Diagram of radio wave as it around through timing ce Hack part represents positive wave; cross Honed part the i crystal. tioned above has a fondness for the posi- tive kind of electricity, but won't have anything whatsoever to do with !the negative kind. The crystal opens wide its door to the waves that are positive, but the door is slammed in the face of the other waves. This exclusiveness of the crystal is a fortunate thing for us. If the radio waves are trotting around our receiving circuit at a tremendous speed and we insert a detector in their path just one-half of all the waves will be rectified. "Shielding" the Set UNTIL- the coming of the mod- ern regenerative receiver, the term, "shielding," as applied to radio apparatus, was quite un- known. The regenerative receiver, however, being supersensitive to all electrical influences, has been found to require protection against external electrical - disturbances. Shielding accomplishes this. It is the process of surrounding the en- tire receiver, and, frequently, the individual circuits therein, with a metallic surface. This generally takes the form of a copper lining in the cabinet and on the rear of the panel itself. Shielding takes care of the energy loss from the wind- ings which tend to induce another current in the same manner that radio waves induce electric cur- rents in a receiving antenna. JDigitized by Google

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RADIO WORLD 11 How to Make Your Aerial Function ALTHOUGH any alternating current will cause a disturbance in the ether regardless of the size or shape of the circuit, in order to create the maximum disturbances pos- sible with the power available, it is necessary to erect an aerial. An aerial or antenna, as it is some- times called, is a system of wire or wires stretched above the surrounding objects and connected to the radio set. The aerial is used for both receiving and transmitting, a switch or other transfer method being used to connect it to one or the other, according to the station sending or receiving the mes- sages. The wire used in aerials is either bare copper, phosphor bronze, or cop- per-clad steel. The ends of tile wires are insulated with special insulators and the wire led into the house through an insulating tube known as a "bulk- head" insulator. The problem of installing an aerial presents considerable difficulty to the beginner, but as a general rule, by bear- ing in mind just exactly what function an aerial performs, the problem is simplified. The average receiving set will operate with perfect satisfaction if a single wire — about size No. 14 — 100 to 150 feet in length is used. It is not absolutely necessary to have a fixed length. The wire may vary between 150 feet and 300 feet, and satisfactory results will be obtained. The function of an aerial is to collect die electro-magnetic energy sent out from the transmitting station and con- vey it, through the receiving set, to the ground. As any conductor will per- form a similar function, it is desirable that the aerial be suspended above sur- rounding objects. The electro-mag- netic energy then reaches sthe aerial wire before it reaches any other object with the result that the receiving set re- ceives more energy than would be the case if the wire were below surround- ing objects. In laying out an aerial, always en- deavor to keep the wire level. If this is not possible, fasten the end from your receiving set as high up as prac- tical and let the end from which the wire reaching to the receiving set is taken, be the lower end. Do not at- tempt to stretch the wire too tightly; it is of no particular advantage. It only raises the center of the wire a few feet and puts it under a severe strain which may result in breakage. This is especially true if sleet or snow col- lects on the wire. In stretching the wire, try to elimi- nate as many bends as possible. Bring By Horace Beers INSULATOR WIRE CONNECTING ALL AERIAL WIRES INSULATOR / WOOD SPREADER INVERTED L AERIAL WOOD 8PREADER . WOOD 3PREADER WIRE CONNECTING ALL AERIAL WIRES INSULATOR Diagram of various typas of aerials. Tba 4- wire aarial shown at the inverted-L type, which may bs used tor receiving a* wall as two lower aerials are the IncUnod type. They may be used for to the . The the conductor leading to the set directly to your window without fastening it to the building. It is of great importance to keep this wire away from the sur- rounding objects, as there is a capacity effect between the wire and surround- ing object which robs the aerial of some of its energy. It is not possible to give specific di- rections on the erection of aerials. Each particular house presents its own problem. With a little ingenuity an amateur may construct easily an ef- ficient aerial in any place. In con- necting aerial wires, be sure that per- fect contact are made. When pos- sible, always solder the connections. This is important. Accessories May Be Used to Increase Wave Lengths THE average receiving set is usu- ally capable of operation over only a comparatively narrow band of wave lengths. This should not be considered, as a great fault, because sets can be more efficiently designed to operate over a narrow wave-length range than over a wide one. But occasionally it is desirable to hear stations that oper- ate on wave lengths higher or lower than those afforded by the tuning ap- paratus of a set. Sometimes an aerial may be too long to work with a cer- tain set to hear the shorter waves and some means must be provided to cut down the natural period. An accessory that may be attached to a set to increase its1 wave length in order to hear some of the longer wave stations is called a "loading coil." This is connected in aerial and ground. When a two-circuit receiver is used, another coil must be connected in se- ries with the secondary in order to balance the two circuits. When a loose coupler is used, a moderate amount of loading may be used in the primary circuit without any in the secondary, as the secondaries of these instruments are usually wound with more wire to compensate for the slight loading. If a shorter wave than the natural wave- length of the aerial is wanted, some sort of condenser may be connected in series with the aerial circuit. This condenser is usually of the variable air type, though it can be of the fixed variety. Where a short-wave con- denser- is used, a single pole switch may be provided so that when it is not needed it can be short circuited without any trouble. Digitized by Google

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12 RADIO WORLD How to Avoid Interference when a 360-Meter and a 400-Meter Station Are Operating Simultaneously By C, W. Horn, Superintendent of Radio Operations, Westinghouse Electric & Manufacturing Co. THE U. S. Department of Com- merce, in order to assist radio broadcasting, has specified two wave lengths on which broadcasting may be conducted. These wave lengths are 360, the one in general use up to this time, and 400, just re- cently allotted. While these wave lengths are 40 meters apart, there will undoubtedly be considerable confusion on the part of those owning radio re- ceivers who are situated in close proxi- mity to one of the stations. For the purpose of assisting those who are so unfortunately located that two such stations are picked up by their re- ceivers simultaneously, I will describe a number of methods which, if ap- plied, should greatly assist those de- siring to get either one of the two waves without being too greatly in- terfered with by the other. There is one case, however, which will be very difficult to assist, that is where the re- ceiver is exceptionally close to a broad- casting station. By close is meant within a few thousand yards. The assignment of two wave- lengths so closely together will have the effect of stimulating construction of radio apparatus which will be capable of tuning more sharply, and it is the old case of "necessity is the mother of invention." Therefore, while there may be some inconvenience at the present time, this should be over- looked in order to help the radio game by creating a condition which will stimulate the construction of better apparatus and which will permit, per- haps, in the future the assignment of more wave lengths, thus creating a better situation in the air. One of the greatest faults that the writer has found in connection with the installation of radio-receiving ap- paratus is that it is believed that the more wire and the larger the antenna, the more will be received. Exception- ally large antennae make it more diffi- cult to tune sharply, and for this rea- son it is advocated that very short single-wire antennae, approximately 75 feet long measuring from the appara- tus to the far end, be utilized, such single-wire antennae to be stretched In a New York Y. M. C. A. Radio School (C. K»<!«1 ft Herbert) Operator William Pecquet sending ■ message in the radio school of the Y. M. C. A., New York. This school pnsMMea soma at the mast up-to-date radio apparatus In the country. It is utilised for practice on commercial transmitting and receiving-. The transmitter Is at the left; the receiver at the right. away from all metallic objects and run straight and clear of all obstructions. Secondly, do not run the antenna or the lead-in over metal roofs, along water spouts or drains, or parallel to telephone and power wires. Frank Conrad, assistant chief engi- neer of the Westinghouse Electric & Manufacturing Company, has made measurements and drawn resonance curves which show that a short low antenna tunes much more sharply than a large and long antenna. This holds true both for coupled and single-circuit tuners. Another method to pursue in over- coming interference, especially where vacuum-tube receivers are used and where the receiver is located close to a broadcasting station, is to make use of the well-known directional properties of the loop antenna. A very simple loop may very easily be constructed by winding a half dozen turns of wire, spaced about one inch apart, on some framework, which can be rotated. It will then be easy to tune out a station which has a difference of 40 meters in wave length, especially so as a loop antenna forms a closed circuit which can be more sharply tuned than an open antenna. Both ends of the loop should be connected across the an- tenna and ground terminals, and no other ground or antenna used. Radio enthusiasts who are more for- tunately located — that is at but a short distance from a broadcasting station — may tune, without any difficulty, in either one of the wave lengths men- tioned. They should, however, bear in mind that a single-wire antenna, not too long and kept free from obstruc- tions, and not running near grounded metallic objects, will tune sharper. Where the amateur has a transmitting apparatus it is desirable to have a fairly large antenna, with more than one wire. If such is the case, he should use a separate wire for receiv- ing. The ideal condition will be when stations can operate independently on either side of two wave lengths with- out interfering with each other. Be- cause "the receiving apparatus is an im- portant factor these suggestions are given in order that owners of receiv- ing apparatus may have the necessary information to increase the efficiency of their apparatus. Digitized by Google

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RADIO WORLD 13 Another R-W Page of Hook-Ups % e % ,,c,,.rS" Audio Trons. ^.<P Realizing that the most Interesting phase of with the svarag* "fan" is tka tasting out of hook-upa. Radio World will publish, from Una to time, a paga of tha moat interesting diagrams, soma of which hara alrsady appsarsd in Its pum. Aa adHar guides his poller by tha wishss of his readers, and tha number of requests for back numbers a these dUarams indicates that then is an demand for them. Schematic diagram showing common type of transmitter used in low tube seta. In this circuit, the microphone modulates on tha grid of the &/T This is a vary good telephone transmitter. Drawn by C White. fteostat 6 Volts Orel //a tor i/onoiff Cor,*/ ■7T Schematic diagram of • lagaaerarlve circuit em- ployiag a tickler coil aa mesne of regeneration. The dotted linos show how the magnetic Baas of force act about the primary winding of the re- ceiver and the tickler coO. Suggested by Fred Chas Ehlert. Drawn by 3. Newman, {Detector diagram of a set in which taw I is employed aa a direct feed- back. Two tubas are nerd one aa a modulator, tha other as tha oscillator. i- satisfactory circuit for C-W work, especially for amateurs. Drawn by C White. II Single-slide tuner employing, as means at tion, a crystal detector. This type rocorror la capable of receiving broadcast programs twenty-five miles. Suggested by Horace Drawn by S. Newman. I < Plot Con J I with A Basque method of employ lug regeneration Schematic diagram of a practical circuit, employing the following apparatus! A-B is a varto Is detailed In tha above circuit. This la of C-D is also a vario-couplar having a wave length from 1M to tea meters. Tha tickler is wo the single circuit type. It also utilises a IS turns of wire (bank wound). E la a variable grid-leak, 1% to S volt Mas. F is a fat odder cod and la hooked In tha circuit. of about 1 megohm, G-H shows optional connections, the grid bias being from • to 8ft volte. 11 is a Suggested by John Kant. Drawn by S, laud speaker. N is a door-bell transformer (primary open) using 11* volts as choke. Suggested by Newman. Dr. O. S. Kelly. Drawn by S. Newman. Digitized by Google

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14 RADIO WORLD Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Leagths for the Busy Reader. NO. 64 BROAD STREET, New York City, the building to be purchased by the Radio Corporation of America for $1,000,000, is known in the radio world as the "heart of world- wide wireless," as from here there are more circuits handled than in any other place or country in the world. The build- ing itself is ideally located for the purposes of the company, because it is in the center of the financial and commercial district of New York from which a large percentage of the traffic handled originates. The building is within two blocks of the principal cable and telegraph forwarding offices and particularly near the Postal Telegraph Company's office with which the Radio Corporation has recently entered into a traf- fic arrangement whereby the Postal Company collects and distributes trans-Atlantic radiograms from and to all points in the United States. The building is ten stories high and con- tains 43,000 square feet. It is known as the White Oil Build- ing, but the name, in all probability, will be changed to "Radio House." It will be remodeled to meet the needs of the cor- poration and to house the executive, sales, and engineering de- partments of the corporation, now located in the Woolworth Building. * * * Dr. Samuel Wesley Stratton, for the peat twenty-one years director of the United State* Bureau of Standards, and one of the leaders in radio legislation and standardization, was elected recently president of the Massachusetts Institute of Technol- ogy. He will take up his new duties on January 1, 1923. * * * During the next six years more than three hundred billion dollars will be spent in the additional electrification of America, said Frank E. Watts, New York, editor of the "Electric Record," He Telephoned by Radio from San Francisco to London (C. International Keel Pnoto; H. CORDON SELFRIDCE, JH, Son of the London merchant, was photographed In San Francisco, while telephoning by radio to hi* father, in London, MM miles away. in an address to the annual convention of the National As- sociation of Electrical Contractors and Dealers. "The possi- bilities of electrical development are unlimited," said Mr. Watts. "Eight million homes in the United States are now wired for electricity, six million are not. Half of those will be wired within the next few years. How rapidly the central power sta- tions are expanding is indicated by the fact that, last year, the light and power companies spent $750,000,000 in new develop- ment. And in the next six years they will spend a total of four billion dollars to extend their electrical service to the homes and factories in America." * * * President Alfredo Zayas of Cuba has formally inaugurated radio broadcasting in Havana. His speech announcing this im- portant event was delivered in the national palace and shot out into space from the sending station of the Cuban Tele- phone Company. Special transmitting apparatus was installed in the palace to carry the president's voice from that place to the radio room of the telephone company. The wave length used was 400 meters. The station was erected by the Inter- national Telephone and Telegraph Corporation of New York. Experimental tests made in Havana developed the fact that amateurs in the United States as far north as New Jersey were able to hear phonograph records broadcast from Cuba. * * * Captain Powhatan Page, vice-president and general manager of the Pan-American Wireless Telegraph and Telephone Com- pany of Buenos Ayras, who has been in New York City nego- tiating international radio connections for his $156,000,000 South American plant, says that a misapprehension has arisen through a paragraph which said "the combined plants represent an invested capital of $170,000,000." "This is perfectly true, of course," Captain Page said, "but certain readers appear to have inferred that cooperation in operating resources involved also a combination of this huge capital under one board — in short, that the world's leading radio concerns had formed a trust. What I desire to make plain is that the figure $170,000,- 000 represents the combined capital of all the radio interests mentioned, which is in no way affected by the international cooperative plan. Each company is as separate and distinct in its own sphere as before and absolutely directs its own af- fairs. The finances of the various radio companies concerned are not combined, as appears to have been understood in some quarters." * * * The United States Government now maintains ten broad- casting stations for the purpose of sending out crop and mar- ket news. * * ♦ A feature of the Closed Car Show at the Grand Central Palace, was a radio-equipped automobile which operates with- out antenna and ground wires, a condenser made up of a cop- per screen and the chassis forming the wave collecting sys- tem. This car, a limousine, had the distinction of being the only machine at the show so equipped. One plate of the con- denser, a copper screen, is fixed between the roofing and up- holstering, thus completely concealing it from view. The metal parts of the machine, being all joined together, form the other pjate of a large condenser, having air and passengers as a dielectric, the separation being about five feet. The prelimi- .nary tests of this apparatus proved that such an application of radio reception is highly feasible and very satisfactory. * * * It has been suggested that the President of the United States set aside ten minutes each day for a personal radio talk with the American people. * * * By operating on two different wave lengths, one 450 metres and the other 350 metres, a two-way radio talk was success- fully carried on between Portland, Oregon, and Los Angeles, California. * * * Broadcasting descriptions of missing persons is now one of the most important uses to which radio is being put. * * • Radio insurance is now being offered, covering fire, lightning, breakage and theft. * * * French children are turning from mechanical toys to minia- ture radio sets. These tiny sets are being turned out in large quantities by French manufacturers. Digitized by Google

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RADIO WORLD 15 Radio and the Woman By Crystal D. Tector I WAS in the train from New York Gty to New Rochelle, the other day, and two women were chatting in the seat be- hind me. One of them remarked, "Well, women are in every- thing, to-day, even radio." She almost took my breath away— indeed, I nudged Friend Husband with sufficient force to jar him from his afternoon paper and, turning, looked the speaker squarely in the eye. I presume that the look on ray face betrayed my surprise; but, realizing that I had put myself in a position to be criticized, I mustered every bit of courage at my command and asked : "Are you interested in radio, madam ?" * * » "Oh, I have to be!" she exultantly exclaimed, as soon as she realized that I did not intend to be rude by my sudden intrusion. Then we "got together," as the men say, and most formally in- troduced ourselves; and I whirled F. H. about in his seat and introduced him too. And my new acquaintance proved to be a most charming person — an instructress of radio classes in girls' private schools. Her brother) she said, was radio officer on a steamer in the Pacific, and he had told her so much about radio that she "just took to it as a duck takes to water," as she tersely pot it All that she knows her brother taught her; but she is patting the knowledge to the most practical use — making it earn her a living. * * * And why shouldn't radio appeal very strongly to women? It does seem to me that but few of its elements— if any— axe beyond the reach of our sex. And, this week, I am pleased to show you a picture of Clara Kimball Young, who we all know as one of the moat attractive of "movie" stars, actually putting together her own set No doubt, any woman who cares to go deep enough into the mysteries of radio will be able to do the same thing. When we take into consideration the fact that little children are among the most ardent radio fans— that they seem to master its apparent intricacies — there is no reason why we grown-up women should hesitate to become fans, too. « * » I am told that radio is one of the most attractive things ever put before the little ones. I am told that no mother — or father, for that matter— should deny the little ones their right to become j pBetaitapMt, Im Aatmm) Young actually ptittlaf together her own eet Any who carea to go deep enough Into the mysteries of radio will be able to do the same thing.'* interested in this wonderful science. Just what is the particular psychology that makes it appeal so strongly to children, I do not know. Perhaps some of you mothers can tell me. Nevertheless, it is a fact that radio does possess some far-reaching interest for the little ones that — like electricity itself — cannot be explained. e e » I am glad to see that the broadcasting programs have their quota of women artists. But I want to tell particularly about Miss Miss Belly B.tc. (h, California which she played munc that wa* to Hav Betty Bates, the San Francisco violinist, whose music, played in the City by the Golden Gate, was heard in Havana. Over 13,000 fans reported having heard her. Her music was sent over a 5,000-mile radiophone circuit connecting Havana, Cleveland and San Francisco. Miss Bates is a violinist of considerable merit whose playing by radio was a broadcasting event e e e Here is a little advice in answer to many inquiries: In all radio-frequency amplifying circuits it is absolutely necessary that a potentiometer be used across the A battery which lights the filaments of the tubes. This stabilizes the en- tire circuit and enables the operator to put the proper amount of negative on the grids of the radio-frequency tubes. This function will be further assisted by placing a by-pass condenser of at least .001 mfd. capacity across the grid lead and negative side of the potentiometer. e e e (Th* follnwing Uttrr i» »rlf-rrplat>HtnrV u> ore plrnMd to gratify our coiTrapondent'M iruA, though %f hrr ammunnofton hod arrived an Auur iMtr in« pres$tt wxruld K\t £<fi<or.) Dear Mr. Editor! — I hove juet received tail w*afc*a copy of RADIO WORLD and I an so enthuaad ever year euggeetJen for a National Radio Work that I Immediately phoned Friend Husband to bis office and told him that we would certainly give a re din party during that —eh a really big party to which mostly etrangers to radio wiO be invited. You may count on ma lor all the help I can give. I think that the different broad- casting etatiatu should announce it in soma good slogan like, "Are you prepared for National Radio Week 7" once a day. until the event geta started. Yours lor "The Big Weak."— C. D. T. Digitized by Google

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16 RADIO WORLD Latest Radio Equipment for N. Y. N. G. By Walter Miller (Both photo«rBH)hi a Intarnmtlsnll Nem-RMl) •yHE newest radio aid* used by the radio detail of * the 71st Infantry, National Guard of New York, are shown in the accompanying illustrations and the illustration on the front cover of this week's Issue of Radio World. The 71st Infantry is a licensed station with the call BY*, Sending and receiving is accom- plished at the same time by using the loop antenna for reception and an outdoor cage-antenna for trans- mitting. BY4 sends both telephone and telegraph sig- nals and has been heard throughout the Eastern United States. The upper illustration shows the Interior of the radio room of BY4. The lower illustration shows how sending and receiving are accomplished simultaneously, on seventy meters, by the loop set. A break-in sys- tem is used which gives Instantaneous message traffic without the necessity of throwing a sand-receive switch. Instructors who have qualified as experts in their respective lines, are in charge of the various classes; and the men of the battalion are enabled to enjoy the best of instruction and training. Lieutenant Grant Layng is in charge of the radio work of this detachment of the 71st. Aa excellent opportunity is open in this organization for radio oper- ators and other technical men who desire a radio edu- cation; but because of the limited number of men designated for the detachment those selected finally must qualify thoroughly both technically and fa a military sense. Drills and classes are held on Tuesday night and Friday night of each week. Applicants should apply to the Armory, Park Avenue and 34th Street, on either night. Digitized by Google

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RADIO WORLD 17 "Close-ups" of Recent Radio Devices Ksdel & Herbert News Photos) One of the most important elements In radio Is the proper circuits in working out a tele- phone broadcasting-station. During the recent World Series it was most important that all the circuits were of the correct value. In order to accomplish this, each line had to be tested out. The above photograph shows the new special- type of voltmeter for testing the voltage by which were sent to WJZ for broadcasting. (C. Kadel & Herbert News Photos) In radio work, the storage battery plays an im- portant part. One of the first things the amateur is taught is an understanding of its functioning, and, also, how to take care of it. The storage battery is a necessary element in radio and one Its main parts. The above photo- C. A. Peterson, director of the De- of Electricity, at the Y. M. C. A, New York, explaining a nei (C Ksdel & Herbert News Photos) John Frazier photographed speaking into the very latest thing in microphones. Mr. Frazier was sent by the Westlnghouse Company, Pittsburgh, to assist New York City experts in the broadcast- ing of the recent World's Series. His object was to see that no transmission lines. The photograph below shows the Finch radio relay. It is a very recent radio invention which automatically receives and records code messages on paper tape — messages which may be read as reports are read on a stock ticker. All that is is to connect the radio relay to a It simultaneously. «' Phottnewa. N. T.l (C. Kadel ft Herbert News Photos) This little device tucked under a table in the operating room of WJZ, Newark, plays a most important part In the successful broadcasting of big news events. The telegraph wire carrying the news enters WJZ at this point, and the above device, consisting of resisting coils and transformers, eliminates all distortions on the line. This is a great relief, as It lessens all that unnecessary tinkering which is experienced in the phones when re- ceiving. From this point, the line enters the speech •nrplifier and from the speech amplifier it Is transferred to the modulators, thence to the aerial. Contrary to the of many, a second microphone is not used In at. Digitized by Google

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18 RADIO WORLD Secret Lines of Radio Communication WASHINGTON, D. C— Back of the commercial systems of world communication, known and used by both government and pri- vate interests, lie existing lines of communication little known to the public although not strictly "secret' Only recently, when the "Terrible Turks" threatened the Dardanelles and Southeastern Europe, the State De- partment asked the Navy if aid could be given in the transmission of dis- patches to the Near East in the event that communication service to that quarter of the globe was broken. To this question, which caused the State Department some concern, the Naval Communications Service made reply as follows: "Our lines of communi- cation to the embassy at Constanti- nople and all our naval craft in Turk- ish waters are established and in offi- cial use to-day. We can communicate with Admiral Bristol within a few minutes." It has been stated justly that naval communication circles the world. So it does, with the exception of very few corners, and three-fourths of the com- munication is handled by radio. To-day, when a dispatch for Ad- miral Bristol is filed in the Navy De- partment, it goes out at once through the Annapolis radio station to a French radio station, thence by land line to the office of the American Communication Service operated by naval personnel in Paris, where it is checked and forwarded by wire to Coblenz. The message is relayed elec- trically at Coblenz from the office of the Chief Signal Officer of the Amer- ican forces in Germany, where Army operators handle the wires to Vienna. The Vienna station is in the Austrian Telegraph Building, but the station is operated by the United States Navy. From Vienna the message goes for- ward by naval radio service from the station at Laareburg direct to the re- ceiving station at the American Em- bassy at Constantinople, where naval personnel again handle the dispatch and forward it to the naval ship on station there, which relays it to its destination. Admiral Bristol is in charge of all American naval vessels in Turkish waters, and the presence of his destroyers makes a sort of fan to all points of which messages can be relayed by radio and delivered from the vessels to other points. In the event of a break in die wires from Paris to Vienna, messages for Con- stantinople would be radioed by French stations to Vienna and to Uni- ted States naval vessels in the Medi- terranean. By Carl H. Butman The route of messages from points in the Black Sea to the United States is similar, except that the outlying ship transmits by radio to Constanti- nople, either to the station ship or the Embassy, but only the ship can send messages. From the station ship the message goes by radio to Vienna, thence to Coblenz by wire and through to Paris, where dispatches are turned over to French Radio Service for transmission, either from Lyons or Lafayette, to Bar Harbor and deliv- ered by land wire to the Navy Build- ing in Washington. This system, though seemingly somewhat roundabout, is nearly direct and is good except that it is subject to delay on account of schedules, as the Allies all use the same route in and out of Constantinople and keep it busy twenty-four hours a day. The "Dashboard Special" Makes 40,000 Mile Tour, Equipped with Radio (Both photographs by General Photographic Service, N. Y. C) An automobile with a loop aerial In front of the wind screen and a receiving aat on the dashboard recently made its appearance in the streets of New York. Crowds gathered wherever it stopped and listened to the music of broadcasting stations. Mr. and Mrs. J. C Davenport, owners of the car, were testing out their new radio set, known as the "Dashboard Special." They had just completed a forty-thousand mile tour and were about to leave on a second tour of indefinite duration., The upper picture shows the "Dashboard Special" In front of the Pennsylvania Station, New York City. The lower picture ehows Mr, Davenport and the arrangement of his car's fine radio equipment, Digitized by Google

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RADIO WORLD V Kamoi" Claims Prize Radio Japanese Naval Craft, Experts Say, May Now Boast Finest Installation MT7"AM0I," fuel ship of the Imperial Japanese Navy, which steamed out of New York recently, en route to Japan, on her maiden voyage, has the most elaborate radio-equipment of any other ship afloat, according to radio engi- neers. The most recent inventions in the field of radio art have been included ip the outfit, the greater part of which was furnished by the General Electric Com- pany. Included in the transmitting equipment are a 1 -kilowatt radiotelephone and radio- telegraph set which may be used for te- legraphy on continuous or interrupted continuous wave; a 20-kilowatt telegraph transmitter and a 2-kilowatt 500-cycle ' quench spark-transmitter for telegraph only. The reception equipment comprises a long-wave receiver with a range of from 1000 to 30,000 meters and a short-wave - receiver ranging from 200 to 7000 meters. In addition, there is a superheterodyne receiver for long and short waves, and a standard three-tube commercial-ship re- ceiver with a range of from 200 to 7,000 meters. An interesting feature of the installa- tion is a radiotelephone exchange, by means of which the ship's operator can transfer control of radiotelephone trans- mitter and receiver to any one of several stations. These stations are located in the commander's room, the commander's office, the senior officer's ward room, and the bridge. By means of the telephone exchange, the commander, or any other officer, may communicate with any ves- sel in the fleet from any one of the sta- tions on the "Kamoi." The exchange board differs very little from the usual tel- ephone exchange. A red light indicates that the receiver has been taken from a phone hook, and the operator, by throw- ing a switch, puts the officer in imme- diate -control of transmitter and receiver. There is also a radio compass by means of which it is possible to find the direc- tion of distant transmitting stations. The "Kamoi" is the show ship of the Japanese Navy. She was recently com- pleted by the New York Ship Building Corporation, and is the first vessel of any navy, other than the United States Navy, to be electrically propelled. The electric- drive equipment was designed and in- stalled by the General Electric Company. The "Kamoi" is a 20,000-ton, 8000-horse- power vessel, and will make fifteen knots. Her main propulsion unit consists of an 8000-horse-power Curtis turbine genera- tor which supplies power to two 4000- horse-power synchronous motors directly driving the twin-screw propellers. There are also two 400-kilowatt direct-current turbine generators which supply the ex- citation current as well as power to op- erate the auxiliaries, such as the main circulation pump, main condensate pump, sanitary pump, and blower motors. An- other feature of the propulsion equipment is a 625-kilowatt auxiliary alternator which can be connected to either of the auxiliary turbines in case of the failure of the main driving-unit This small generator will supply sufficient power to drive the ship at a speed of seven knots. The "Kamoi" will be used to carry coal and oil to ships of the fleet. Experts Plan Big Radio Con- structive Campaign TO aid the government and the Ameri- can people in peace or war, to elimi- nate the confusion of rapid development, to work with the Federal departments to devise a rational scheme of broadcasting for the Nation, to promote on a universal scale effective organization of all radio instrumentalities, and in general to under- take at once the solution of the pressing problems of the industry, now leading to conflict," are the declared purposes of the new National Radio Chamber of Com- merce. In a statement yesterday announcing the practical completion of the task of se- lecting the executive personnel of the chamber, which includes the appointment as general counsellor of Henry T. Hunt, No. Ill Broadway, late member of the Railroad Labor Board and former Mayor of Cincinnati, if was said that a commit- tee had been appointed to investigate the whole question of broadcasting. One of the first steps in the committee's work will be to hold an open meeting of the chamber in Chicago during this week at the Chicago Radio Show. William H_ Davis, the president of the chamber, at its headquarters, No. 165 Broadway, summed up the chamber's general attitude toward broadcasting as Follows: "The only scheme of broadcasting which can prevail in any real sense is one in which the end to be attained reconciles all conflicting elements, even to the submerging of pnvate interests." The vice-president of the chamber is Harold J. Power, the secretary, George Lewis, and the treasurer, Lloyd Marshall. The board of governors consists of A. H. Grebe, Richmond Hill, N. Y.; C. B. Cooper, New York; A. P. Morgan, New York; B. L. Moore, Buffalo; J. R. Craw- ford, Long Island City, N. Y.; E. R. Harding, Boston; Boden Washington, New York, and Gordon Sleeper, New York. A plan of regional organization has been adopted by the chamber with the following district vice-presidents: First district (Boston), O. K Lus- comb, Cambridge, Mass.; 2d district (New York and Northern' New Jersey), to be elected; 3d district (Philadelphia, Baltimore, Washington), Atwater Kent, Philadelphia; 4th district (Atlanta, Sa- vannah, Jacksonville), to be elected; Sth district (New Orleans, Memphis, San Antonio), to be elected; 6th district (San Francisco, Los Angeles, San Diego), Col- lin B. Kennedy, San Francisco; 7th dis- trict (Seattle, Portland, Tacoma), Rob- ert H. Mariott, Seattle; 8th district (Pittsburgh, Cleveland, Toledo, Detroit, Cincinnati, Columbus), Powell Crosley, Jr., Cincinnati; 9th district (St. Paul, Mil- waukee, Chicago, Indianapolis St. Louis, Kansas City, Minneapolis, Denver), Harry Bradley, Milwaukee, and Dr. C. F. Type R-3 Magnavox Radio with l i-inch Horn Why MAGNAVOX RADIO is The "Reproducer Supreme" MAGNAVOX Radio is not manufac- tured to help sell one make of receiving set, but to complete the serv- ice of every good quality wireless station. 1. Universal Uw> The Magnavox can be used with any receiving set— the better the set, the bet- ter can Magnavox operate. 2. Simplicity t The hook up is as simple as that of the ordinary telephone headsets. 3. Volume! With the Magnavox, the volume of sound is limited only by the amount of power input. 4. Tone: Official tests with the os- cillograph prove that the Mag- navox electrodynamic receiver reproduces incoming wave forms witb maximum accuracy. 5. Quality: In refinement of work- manship, materials and finish, Magnavox products have no rivals in their field. 6. Construction! The electrodynamic principle involved in its construc- tion makes Magnavox Radio the most efficient converter of elec- trical vibrations into sound waves. The Magnavox Company have been pioneers in the de- velopment of devices for scientific sound amplification. When you purchase a Mag- navox Radio or Power Am- plifier you possess an instru- ment of the very highest quality and efficiency. THE MAGNAVOX CO. Oakland, California New York Office: S7t Seventh At.. Digitized by Google

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20 RADIO WORLD Coupling for Radio- telegraphy No. 1,427,JS». Patented, Anxust Jt, MB. Pat- entee: Joseph Bethenod, Puto, France. THIS invention, on which M. Bethe- nod has been, granted letters pat- ent, both in France and the United States, refers to an improved system ot coupling between radiotelegraphic an- tenna and a high-frequency alternating- current generator of the type of those susceptible to furnishing, directly, a cur- rent of the frequency necessary for the feeding of the antenna. This system is applicable outside of any combination re- Mr. Betbenod'a tn ran Hon wUl be mora easily understood by nhnn» to tb* abora djaxrama. Figure 1 reprooa nts too fractfaning of the winding of the eltama- tor and tha manner of tying with tha ttng^nwaformersi tha Figures 4 and S aaeh represent a modification m tha mounting of tha secondary windings of tha transformer*. Figures 2 and 3 rep- rawit, respectively, fnmt and aide view, the manner of preferred execution for the Independent transformers. Figure * rep- resent tha manner of aaenmbiy of tha quired by the difference of phase that may exist between the currents engen- dered in the different notches of the armature and can be perfectly realized with a monophase alternator. The in- ventor's chief purpose is to avoid, in such a machine, having the insulators stand an exaggerated tension; the means used is to fractionate the winding into several sections by taking the precau- tions indicated in the manner of the tying of these sections to the antenna so that the machine may not be the seat of internal circulation currents. » * * Mr. Dubilier's Condenser No. 1,43,227. Patented, September It, ISO. Pat- entee: WUUam Dubutar, New York, N. Y. A CONDENSER adapted to assume any desired capacity value between maximum and minimum limits, and more particularly to a condenser in which the above is accomplished by combining the capacity of a condenser of the fixed type in which the plates bear a permanent electrons, an anode and an electrode, preferably located intermediate the fila- ment and the anode, the electrode being usually called the grid. These are pref- erably enclosed in an evacuated glass- vessel. The main characteristic feature of the audion is that the amount of the space current flowing between the fila- ment and the anode is dependent on the potential of the grid electrode. It has been found, however, that, when the grid is made considerably more posi- tive than the filament, the tube operates less efficiently and an excessive positive charge may even cause the tube to "blue- haze/' or to be destroyed. This is due to the fact that the grid, on becoming appreciably more positive than the fila- ment, tends to become even more so through secondary electron emission by the grid, this secondary electron emis- sion being caused by the bombardment of the grid by electrons. However, even if the grid does not acquire a charge sufficient to injure the vessel, the charge may hinder the action of the tube in the Figure 1 to a perspective view earn ntogrrr— nattoaDy arastrating a condenser adapted to operate in accordance with Mr. Dub Uler>l invention. Figure 2 to a detailed i r— * form of fixed con- to ba used in place of the ' Illustrated in Figure L and fixed relationship to each other, with the capacity of a condenser of the variable type having a plate or plates shiftable in position as regards plates of opposite polarity to vary its capacity— this is the basic principle of Mr. Dubi- lier's invention. The fixed condenser is made up of sections, or units, which may be cut into or out of circuit to obtain what may be termed stepped capacity-values over the desired range of the instrument, and the variable condenser is arranged to supplement the capacity of the fixed condenser in order to obtain the result- ant capacity values which are intermed- iate the values obtainable by adjustment of the fixed condenser alone. Mr. Dubilier intends to provide a con- denser of the above type which may be adjusted to cause the capacity to rise or fall progressively and uniformly, or which may be adjusted to produce a straight-line curve in capacity changes, and, in its preferred form, a single op- erating member is provided which serves both to adjust the capacity of the fixed condenser to different values and to shift the capacity of the variable con- denser in such manner that, substantial- ly throughout its entire range of move- ment, changes in capacity are effected substantially proportional to the amount or degree of movement imparted to the operating member. Electron-Discharge Circuits No. 1,42*42*. Patented, Alienist 22, 1*22. Patentee: Harry C Egerton, Passaic, New Jersey. *TpHIS invention relates to circuits for A electron-discharge devices and per- tains more especially to audion circuits. Its object is to improve the operation of vacuum tubes, such as the audion. The principal parts . of an audion structure are a heated filament, or other source of EH 1 is'* 4 Figure 1 represents a vacuum tub* of tha audion type having its input circuit con- nected to the source of oscillations by the transformer, and having Its output circuit connected by tha transformer to a suit- able outgoing line or consumption circuit. 12 to a source of current for the output circuit. With such an arrangement the transformer will Impress upon the out- come Una, amplified oscillations of the form Impressed on tha Input circuit. Figure 2 shows how the internal structure of an audion may be modified to conform with the purpose of this invention. S illustrates the invention In connection with an oscillation generator. In order to prevent tha grid from becoming- suffi- ciently positive to cause the tube to "blue base," or generate oscillations of an un- desirable complexity, the electrode of the unilateral device is connected to the grid and the ft lament to tha filament. case of a repeater or amplifier by start- ing free oscillations in the tube circuits. Such free oscillations would be unde- sirable also where the tube was employed as an oscillation generator. In order to overcome these difficulties, it is proposed to afford a leakage path to the filament for the positive charge on the grid by connecting a unilateral im- pedance between these two electrodes in such manner as to allow current to flow from the grid to the filament, but not in the opposite direction. Radio will diminish crime and increase religion. — Marconi. Digitized by Google

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RADIO WORLD 21 Agents LABOa lCAMnTACTUWB or SHJBT8 null Areata ta nU •snplets Bm if abtrls dbiat M •••nr. BsalaslTe nana. Ms tsIms. N. eapltal m anaaaaei nqolrad. Wrtu Mr tm ■■»!■ MADISON BBm ami* SIT Braadwaj New Tart. N. T. "MIRAD" "Qodity RmEo Priced Right" I Plate Variable Coadau Mired Variceaalars MM Oka DauMe HW I UM Oaai S4a«U Head f (MtMTbKk |MWh») Mind 8 Plate Cm " Mired O Plate V. Mlrad Dstecter Unit, atbad Two-Stap Ami Porta** Paid Dealers' Sanpea of AWn M% Oft? Miracle Radio Mfg. Co. DVTERURBAN BLDO, DALLAS, TEXAS UNIT RADIO SETS PrZJSaVaTSiw'rt QaeaBe? Nsw Tare CHy. PRICM and QUALITY our prtmitr oofuioaroMon Jp::::::::::/.:::::!J:86»jg nWAaaS aa i ia*:::::::::: StSS r preeeaMaa ImnaHali DaHoary RjmSo A Ebctrie Co. r. Maw Yark CRy Bo Supplies I Hoadsata, Sockets, RhaXMtets, Etc. ' °»35 'Crystal Sat $/i Or Many Rafaaded PRICE, *X 5«ad *ftj erate /or M aftorat bW^rw* eeaa a**. Aay lUale Sat Made to OraW ar Repaired Sunbeam Electric Co. H THUD AVE. NEW YORK NOVO FOR RADIS N O I SELE S, DEPENDABLE GUARANTEE ASK YOUR DEALE NOVO MANUFACTURI 13 O W. j NEW. VOHI Moving Picture Manager Objects to Radio UNDER the heading, "Detroit Papers Rebuked by Trendle, Kunsky Man- ager," "Moving Picture World" publishes the following: The following letter was sent recently by George A. Trendle, manager of the John H. Kunsky theatres, to the Detroit Free Press and the Detroit News: "I have recently learned that the Gov- ernment desires to curtail the operating of the radio broadcasting station of both your paper and the Detroit Free Press, and understand that in the very near fu- ture you*' will be called into conference for that reason, and am taking the liberty of again\writing, in the hope that you will seriously consider the advisability of discontinuing the use of the radio outfit after 7 o'clock in the evening. "We are spending many thousands of dollars with your publication each year to increase the attendance at our motion picture shows. Undoubtedly it is a self- ish motive, but at the same time, an ex- pensive one, while your publication at no profit to itself, makes a strenuous effort to keep as many of our patrons away as possible by giving them lavish entertain- ments during the evening, without ex- pense. This does not seem to our or- ganization to be a fair and just return for the co-operation we are giving your pa- per, and if you can eliminate the broad- casting during the evening hours, giving your patrons the benefit of it during the afternoon or morning, I am sure that you will eventually benefit by it "I am writing the Free Press and mak- ing the same request, not as a favor, but as a strictly fair and square business consideration, to which I feel that the theatres of Detroit are entitled in return for the enormous amount of advertising placed in your publication from week to week. Comments are heard from theatre managers daily with reference to this, and it certainly deserves some consideration on the part of the News. "I sincerely hope that after careful thought you will agree with me that the News can carry its message to its many radio fans without so seriously interfer- ing with the operation of amusement en- terprises in Detroit, which. I am frank to say, have not come back to normal since the inception of the News and Free Press radios. Our residential houses par- ticularly have been seriously affected and we can give no other reason for it." New Broadcasters Licensed THREE new broadcasting stations were licensed during the past week: KFDD — St Michael's Cathedral, Boise, Idaho. WNAP— Wittenberg College, Spring- field, Ohio. KFEB— City of Taft. California. Only One Licensed Broadcaster in Berlin There is only one licensed broadcasting station in Berlin at present, and this sends out mark and exchange quotations. Ser- vice charges range from 1,000 to 7.500 marks a month, to which must be added the cost of the Government license and the installa- tion of a receiving set. —Rocky Mountain Crystals—, arrria than oalcna t ommfmnmrtri. Jtmmrrt, Dtairrt. (-ft Arfh for SfrcUi Trad* Print Betty Mm** Mb Prefads, he. a MMN aT. m vim, a. v._ RaaaaiaMadrd my Drain tor CalleMRr QADIO STORES COW. FAMCB UHITaV ETC ■ Bit raw tamw assart awn, aOwam —at. a. ttt mam S4M aaart, Mao Vara GOING— and Going Fast WtanabiaiWlaaaaai Nat mm etta) mm mat a* aM mama mil mm — - - VT 1 VT 1 I*, am tana an ma sasaae atae T* mm ■*«. l—Hiell. "RADIO BUILDER- PLANS FREE I ..*Ja LIBERTY RADIO CO. MS LaVarty Strart Naw Yark < LEE RADIO CORFN. Haddoaleld Naw Jane? ANNOUNCES THEIR "B-l" SET (Facta* Applied Par) NEEDS NO AERIAL PRICE, $35.00 Oeaaplete Bzcea* "A" Writ* tar 50c. RUSONITE PRODUCTS CORPORATION is park aaw. mcw vans TUNE IN DISTa4NT STATIONS $40 F. R. 8. Complete Two-Stago Raage Receiver P*t Includes two Federal Transformers, Conri.nwr, two molded vajlom.t.ra, molded varlocouplsr. three V. T. sockets, filament rheoetata. dials. Read 'mm binding poeta. switch point*: la attrac- tive cabinet and drilled panel: complete, ready ta A HIS Radio for. F. R. 8. Ail-Ware CoaaUaatlem Maided Varioatetera, $LM. Molded Vartocoaplers, UM. Molded Baak Wladlag, $SM. Bank winding ta Interchangeable for dlrx-t mounting on alther Variometer or Var iocoupler. Thi. la the only all molded universal combination giving five unit. In three. Fn c RADIO • IX. O. CORP. m East Fort SL Detroit, Mich. Digitized by Google

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per page Radio Merchandising Classified Quick-Action AdrertUiag, 5 ceats par word TeUfhons Bryant 4796 To Radio Manufacturers! Send This Firm and Its Branches Your Catalogues ASSOCIATED ADVERTISING CLUBS OF THE WORLD EXECUTIVE OFFICES, 110 WEST 40TH STREET , NEW YORK Radio World, 1493 Broadway, City. Gentlemen: We hare to-day received the following letter from: Och Freres, 2, Rue du Marche, Geneva, Switserland: "Our Mr. Och is going to publish in the Swiss newspapers the result of your great expansion in radio. Would you be so kind as to let us have the catalog of your radio- equipment manufacturers and, if possible, samples of the special radio papers sold in the United Statest" Will you be good enough to comply with the above request and send camples of your magazine and advertising matter to Och Freres at Geneva? The house of Och Freres has branches at Lausanne, Montreux, Neuchatel, Chaux-de-Fonds, Zurich, St. Gall and St. Moritz, and appears to be a reputable concern. Very truly yours, M. S. THAYER. Associate Editor. New Firms and Corpora- tions (The firms and corporations mentioned m this* columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Lewis Electric Mfg. Co., Buffalo, $100,000; J. N. Lewis, E. S. Yates, R. M. Stanley. (Attorneys, Stanley & Gidley, Buffalo, N. Y.) Radio Installation Co., $100,000; William T. Hughes, Earle Smyth, Alexander Jamison, Wil- mington. (Alexander Jamison, Wilmington, Del.) Guarantee Electric Co., Atlantic City, deal in goods, $125,000; George P. Proffatt. Katherine B. Proffatt, Walter Hanstein, Atlantic City, N. J. National Electric Products Corp., Wilmington, manufacture, $500,000. (Corporation Trust Co. of America.) Hutchison Radio Co., Del., 200,000 shares pre- ferred stock, $5 each; 400,000 common, no par value; reps.. E. Fallows and J. Lsngner, Madison Av. and 44th St., New York, N. Y. Orator Radio Corp-, equipment, $50X00; L. P. McArthur, Emmett M. Carter, R. B. Dickey, Washington. (Corporation Trust Co. of Dela- ware.) Radio Corp., Wilmington, radio devices, $50,000. (F. L. Mettler, Wilmington, DeL) Electrical Club Starts Radio Class THE Electrical Jobbers' Club ot New York bas organised a class In the practical and technical features of radio, open to any electrical contractor-dealer In tbe metropolitan district of New York City, or any of his men. No charge Is made for tuition. The work covers merchandising. Installation, and opera* Hon of radio sets. A Persistent Advertiser Robinson Crusoe advertised for a ship. His medium was of most limited circulation and had no A B C rating; but he got the ship. Mr. Crusoe did not get immediate re- sults. His advertisement flapped on the pole till the rains and winds tore it to shreds. Bnt he renewed his "ad." In fact, he gave his last undershirt to his faith in persistent advertising; and through his persistence, Robinson Crusoe's name will be handed down from age to age. You, too, will get satisfactory results and create a trade name of permanent value by persistent advertising. Our suggestion is that you give RADIO WORLD a 52-time order obtaining our minimum rate of $4.25 per inch by using a one-inch rate holder and larger space as desired. Among RADIO WORLD'S 70,000 readers we believe are numbered more radio manufacturers, live dealers, and en- thusiastic fans than could be reached for double the money in other radio publica- tions. For full details address RADIO WORLD, 1493 Broadway, New York. Our Quick-Action Classified Ads, at five cents a word, bring big results in one week after receipt of copy. Heard at the Radio Counter A Conversation Between Customer and Radio Clerk (Port II) ^ . SAY, John, did you hear that •Mr* last night working C. W. with a note like a wfllow. Oh. boy! If I only bad another tub* in the circuit, believe ma! I would have heard him all over the room." "Yea, I guess you are right an that; because just when WJZ abut down for a few minutes, I started in tuning for whatever stations t could pick up. The first thing I knew, this •Mr* started up— but it waa sure a good note." "What do you consider a good audio- frequency transformer? I would like to add another atta- in the circuit." "Here, this is a good make. I am using them and get wonderful results. Just try one and aee what happens." "All right— and, by the way, give me a tube socket, also.'* "Have you any need for an extra B battery, rheostat, or leak condenser? You knew, these will be needed when you add the extra tube.** "I guess you better let me have them. Also, better give me about two yards of spaghetti tubing. Now, there la one queetion I would like to ask before I go. What is the best method to determine the strength of my storage bat- tery? I think I need rase acid." "Just a minute. What you need is this in- strument—a hydrometer and holder. It wfO tell you the exact condition of your battery. See where it Is marked 1275? This means that your battery ie O. K, and needs but little charging. Now, when the hydrometer shows list, or even 1200, just say to yourself, 'I better put this baby on charge before it goes to the dogs en- tirely.' One good thing to remember: Never let your battery fall below 122S." "Very well. Wrap up the hydrometer, too." "See you again, O. M." (To be Continued) Coming Events The editors of RADIO WORLD wffl gbuBy publish news items of all contemplated radio shows and expositions. Keep us posted by mailing full Information. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, inclusive, 1923, George A. King, director of publicity, 417 South Dearborn Street, Chicago, lit PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION, Grand Cen- tral Palace, New York City, December 21 to 31. Colwell & Korbell, Fisk Building. New York City, directors of publicity. TRI-STATE TOBACCO GROWERS' RADIO SHOW, Covington, Ohio, October 21 to 28, in- clusive. INTERNATIONAL RADIO SHOW. Madison Square Garden, New York Citjr, November 20 to 25, inclusive. E. C. Buchignani, director of pub- licity. SOUTHEASTERN RADIO EXPOSITION, Audi- torium Armory, Atlanta, Georgia, December 4 to 9. inclusive. Co-operative Radio Sales Assn., 295 Peachtree St. WANTED i COPIES of RADIO WORLD, April 22 and May 2S, 1122. Mail us copies of these issues, or either one, with so accompany postal and we will send yon a copy of the latest issne for esch copy so mailed. RADIO WORLD, 1493 Broadway, New York. Digitized by Google

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RADIO WORLD 23 Navy Radio Sets Bring $43,000 THE opening of bids by the United States Navy Surplus Sales Office revealed the fact that 47 firms and in- dividuals were interested in the 390 radiotelephone sets offered for sale re- cently. The highest bid received was $251 for one set ; the total receipts reach- ing $43,000. The awards made were as follows : No. Amount Total Sets Bidder Address Each Amount Purc'ed Simon Bitterman, 623 S. Wabash Ave, Chicago $150.00 $450.00 3 Wm. Hansell, 116 E. Main St., Ottawa, la 155.00 1 Henry Kienzle, 501 E 84th St., N. Y. C 200.00 1 R. H. Parker, 33 Cony St., Augusta, Maine 175.00 1 Atlantic Marine Ex., 14 Atlantic Ave., Boston 251.89 176.89 126.89 555.67 E L. LeBaron Foundry Co., Brockton, Mass 155.00 No. Western Radio Ser. Co, Seattle, Wash 20000 C C Tylee, 314 Sumter St, Charleston, S. C 162 JO 32500 Klein's Radio & Elec. Co, 34 Park Place, New York 200.00 600 00 Bion J. Arnold, 105 S. LaSalle St., Chicago 125.00 1250.00 H. A. Braunstein, 248 First Ave, N, Minneapolis, Minn 1,514.00 Alex. Rankin, Frostberg, Md 150.00 Catholic University, Washington, D. C 15000 Frank L. Smith, 7 Newberry St, Worcester, Mass 105.00 Eksaf Trading Co., 1515 E Parkway, Brooklyn 206.00 2,060.00 Department of Physics, Cornell University, Ithaca, N. Y 150.00 John W. Lee, Radio Laboratory, Navy Yard, Phila 16000 Robt J. McLain, 6 Chestunt St., Cooper stown, N. Y.. 120.00 36000 Greeley Madison Corp, 26 West 23rd St, N. Y. City. 101.33 34,137.99 3 1 1 2 3 10 10 1 1 1 10 INSU-LITE P A N E L S 1/8" — .91 per sq. la. S/16"— .»15 per *<•. 1b. 1/4" —M per In. DEALERS : Writt tor Mtootmtt. General Merchandise Co. 142 Market Street, Newark, V. i. 1 1 3 336 The Hoyt PEEP-HOLE METER A guaranteed Hoyt miniature voltmeter or ammeter for your board. TJasd with cither A. C. or D. C. current, totalled without screws. Banges: 0-10 Volte St.M O-SO Volte SS.10 0-.8 Ampere* ft.SO 0-l.t Ampere* $S.50 Other range* and price* on application. BURTON - ROGERS CO. TSS Boylston Street Boston 11, Limits Radio Talk to Coastal Areas Norwegian Government Says Strips in Territorial Waters Must Observe Strict Rules of Radio Com- munication. THE following regulations regarding the use of wireless stations on vessels belonging to foreign powers not at war, while in Norwegian territorial waters in times of peace, have been approved by government resolution, and came into force on September 1, according to the "Anglo-Norwegian Trade Journal:" 1. In Norwegian territorial waters wireless telegraph or telephone stations on foreign vessels may not be used, ex- cept by special permission, unless for the following purposes: (a) Communications concerning vessels in distress or for the prevention of acci- dents. (b) Communications; (c) communica- tions with the nearest Norwegian coastal station, and other ships' stations when each vessel is at least ten nautical miles distant from the nearest Norwegian coastal station. In the cases of (a) and (b) commun- ication must at once be stopped on re- quest from the Telegraph Administra- tion, the Naval Department or a station belonging to either of these authorities. 2. In Norwegian ports where there is a state wireless station and within certain prohibited districts laid down by the Norwegian authorities (regarding which information may be' obtained from the nearest state coastal station), the ships' station may not be used except for communications as under 1 (a) unless special permission has been obtained. 3. Application for permission to use a station in Norwegian territorial waters for other communications than above mentioned should be sent to the Tele- graph Administration (Telegrafstyret), which will give its decision after con- sultation with the Naval Administration. 4. (This paragraph concerns war.) 5. When a ship's station is used while in Norwegian waters this must be done with the observation of the provisions of the International Telegraph Conven- tion and its regulations. 6. The foregoing regulations remain in force only when Norway is not at war. Textbook on Radio THIS 350-page volume deserves the most unqualified praise for the thoroughness m which the publishers have endeavored to cover the interests of the radio enthusiast. There are a number of valuable suggestions in its pages which will be of value to both fan and amateur. It is written in a simple style, and, at the same time, it is a stand- ard textbook for the technical radio student. It contains, the up-to-date ma- terial regarding circuits and hook-ups including data on superregenerative re- ceiving sets. This book can be secured from your dealer or direct from the Technical Book Co, 130 West 42nd Street, New York City. GITHENS TRUTONE RADIO HORN— LOUD SPEAKER First *Ml»wl day trial a TOO dart am _ It U *u a i B art earned to Distributor! tmi D—Xtrt, writt I AUTO PARTS MFG. CO. U1S Trembly Ave, Detroit, Mica. YOUR PHOTO IN ^THIS PAPER ATTE/fTIO/f AMATEUftSf Hare yon built your own receiver t Ar* yon experimenting with any per' ticnlar hook-up? Are yon improving your set? Are yon doing any interesting construc- tive work in radio? Why not after* tMt feaotoledo* wUh your ffcouxnut* of brother /an* who road RADIO WORLD *o*ry to—kf We want picture* of receiving seta with description! of how you overcame aoaa* Ufficulty, or of any additional part or unit that you have added to obtain batter result*. There are the thing* that, prob- ably, the other fellow is looking lor. Send in your information; picture* or what- ever you have done to improve the art. Remember the beginner i* looking for them. We intend to print in this paper, each week, pictured information and descrip- tion of value to radio amateur*. If you have found a newer or better way of doing anything, don't keep the secret but tell it to your thousands of brother fans. Sand in a photograph of your act with or without accompanying diagrams and measurement. State whether you figure in the picture yourself, or not, and with- out any expense whatsoever to you we will make an engraving and publish it. Be sure to write your name and address plainly on photograph. Send in your picture at once, or if yon have not made a set or done anything else in making radio material, ten boy next door all about this offer. the Adores* Technical Editor RADIO WORLD. 1493 Broadway. New York City. N. Y. YOUR RADIO WOULD to year NEWSDEALER u la order *s be sure of rettta* RADIO WOULD i and sf as* milling a sfngi* Issue, w* suggest that yea sttknr subscribe drarl or •Velar at tMS a year (HI ■»■■■) (US mm meatus, and OJ» i «s dhfsvar RADIO WORLD regularly as your hams each w World, MM Digitized by Google

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24 RADIO WORLD FEDERAL PHONES $C RADIO DISTRIBUTING O & AUTO SUPPLY CO. 64 Weil 66th St., Set Mr Seaalali la w New York Cit7 t law Nulla Warltf Radio May Rob Volcanoes of Terror PROBABLY never again vius belch its fires of will Vesu- destruction upon an unprepared and unsuspecting populace, or Popocatepetl rain its death- dealing lava upon unprotected Mexican SOMETHING NEW! Variable Condenser Built Right Furnished either regular or vernier Made in the most popular sizes, with aluminum plates, cast end brackets, with a 1" diameter Bakelite bushing therein. (A perfect insulator high in dielectric strength). Dealers write for discounts. Ask to see our Rheostat and Vacuum Tube Socket. LOMBARDI RADIO MFG. ^| $7-71 Minerva Street, Derby, Conn. ent Applied p~ COMPANY P. O. Bos 44 For CORRECT RADIO MAILING LISTS Ui THE POCKET LIST at BaoM Haaafii JjruTTab- eaa ana dUTenat a* aBMBtUaaUr emta ta aa> ta it tkat etar/ 1 ■ dLaaattno&TioH. mm aeiau net « tMa Mail wLt u a rata, tbaaa auppnad an far ha Mat aad rea wtu And it u ka ta* rar# be* tbtataaale aarwkan at aw pnee. "L2SS **. * **.mr. m S1S.M mm (taw k- «a» I1M far a IM Fn PTnflTNQ m casjun(jto»« strrrt • JL/e i IV^lVJCii^O, JANESVHXS, WISCONSIN '♦TUNING IN" TO THE RIGHT TUNE IS VERY SIMPLE WHEN YOUR CONNECTIONS ARE SOLDERED WITH THE NEW "POST SOLDERING IRON" (The Ira* wfta the POST ELECTRIC COMPANY M EAST 4ZND STREET, Dtv. M NEW YORK GREWOL DETECTOR $2.00 Nothing Like It Nothing as Good la a Ma watt aa Mlllll . da aad atlll ml* at and Always Set Ready (Aetna! Siaa) Tba Oiaaal tha etaatbud. cka w ltaalf Mai baa jet baai dr ' a papular prlaa. Aakad far w aaa*. add w iwotatlea. — If raar ewjer aaaaat awe* yea. Glaaa Encased •tad It aad *a will «u jaw are*. Vaw Daalar baa Brawva X^m.-3wr'W . RANDEL WIRELESS CO. Sole United State Distributors t CENTRAL AVENUE NEWARK, N. J. RAr "* ESENTATI VES WANTED! «ta« kaataag aaaecriatioa jreaawjeatanvaa la erery <ra taraoat the coaatry. Scad aa year aad . MR Broadway. " " ~ orfc Qty. peons, says Raymond Francis Yates in "The Evening Mail," New York. Scientists and the wonderful vacuum tube of the everyday radio receiving-set are seeing to that. Work of applying sound amplificatiou to the study of volcanic activities within the earth has already reached the ad- vanced stage. In fact, there has been constructed a device so sensitive that the moving waters of subterranean springs easily can be recorded by it. This apparatus, which might be called the "sound microscope," is so tremen- dously sensitive to air vibrations that h permits one to hear things heretofore absolutely inaudible. It is destined to become as great an aid to hearing and acoustics as the micro- scope and the telescope have been to vision. Does Good Work With Low Power NIGHT by night, throughout the breadth of the land, there takes place a series of communications under the most efficient organization ever pro- duced by voluntary methods, says "The Tribune," New York. The development and operation of this system are the work of the average American radio amateur, under the executive guidance of his na- tional institution — the American Radio Relay League. The work of this organization has to a certain extent been obscured in the phenomenal advance of public interest in radio due to the advent of broadcasting, and only occasionally does an inkling of its achievements appear. Before outlining this, however, it should be pointed out that the amateur owning a transmitting station is restricted to a maximum output of one kilowatt of power by the government Many of the amateurs are still further restricted by the exigencies of their financial standing, but they make up in enthusiasm what they lack in funds. To ^still further understand the con- tribution of the American amateur to the development of radio as a means of com- munication, it should be stated that he also is compelled to work on 200-meter wave length as a maximum, where the frequency of the oscillating current is so tremendously high that it offers almost insurmountable difficulties. Despite these obstacles, he has suc- ceeded in communicating across the At- lantic Ocean with less than one kilowatt of power, where under the same condi- tions the big transAtlantic wireless sta- tions are compelled to use 200 kilowatts. This is unquestionably his crowning tri- umph. Day by day he maintains a network of communication across the country which has already proved its worth in cases of emergency and which is becoming more efficient every day. In addition, he also maintains a daily communication between the Pacific Coast and the Hawaiian Isl- ands with the low power allowed him by the government 4 I I Cat Oat This Radio World Do yon like clear tone— «narp and distinct — If so try MARSH'S Vernier Variable AtSSS to JSSfTS mfd. Fully Guaranteed TbJe Zf plate ilanaat lb To place before the Radio limited number wtn b F. P. Marah, 145 NScholl St. New Haven, Digitized

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RADIO WORLD 25 PATENT Tmm fill ADVICE \f'.V i*** P Wt LOO MI I OOMI IN AND MIAH TMI_ CORACO RADIO CONCERT Mb. • a. M. t* a ». m. ittn rtmr. »• w. 4M St.. Mrt a> «mMu Thtatre Bar Ow aapar-Badlopoai* U tbs Utwt ad »rmm timw— it Id ndU. It has m amide i—IUbi m tnauUetMai umom— U u almple te ntlll M a phaetaTiah It jau mmrm mO. writ* far fall tnfarmatua. THE CORACO COMPANY, INC. m mm 4>m «mt a** v«k ALADDIN ELECTRIC COMPANY, INC COMPLETE RADIO SETS WRITE FOR PRICES. nWntBroMhrtr N«w T«rk CHy ABC Standardized Radio Reeahrtac Ualte aa — " aattafacttaa at 1m ant. Wrila far catalee- Jewvtt MRnnfacltviug Cotrp. At*. Dap*. G, Newark, N. J. Iiiversil Phone Connector CU bt an* with aw tjpe raeater. Maker peaabn th* am at faor arte at phaaea, BOata- ua MMrar "aa Haartlj rdekel-plated, and faar> aataad u (tie —ill lata attlafaitlea. Price 75c a pair DtolerM, Writ* /or Liberal Ditcotmtt tTarrenal Phone Connector Company ■aa UP. MM araanay. Mas Yeri ONy RADIO MAILING LISTS •IT* BataU Badla Dealer*, netted BtaUe par at IT.M UM Badla aUaatarfari par Hat, ll.f* IMP BedU Baaphr Jobber* par Bat. U M MT Badla awnuaiataran at tan- Plata aaa par Hat. 4.** IM Badla SYaUtae par hat. 4.M 14S00 Badte Anetears aad kUa- atwn at Badla Btatfeni... par at T.H Kwutr tfpawrttna aad nadf t* and paa am faaatpt at taalttaaaa aarariac tap aaoaM. TRADB CIKCl LAB ADDRK8HTNO CO. ltd W ADAMS STOUT ' OHICAOO. ILL. RADIO CITIZENS WE SAVE YOU HONEY Send na a list of your radio needs for our prices. If Its Radio, we have it and we tell it for less. JOHN R. KOCH COMPANY CHARLESTON WEST VIRGINIA mi HIE"GOf)])>IAN ■ WWaatSaart Wave Timer aa tl OaJjr HM * PP oa 1 lb. af far paaapaJet. Order through rear dealer. L. W. GOODMAN DREXEL HILL, PA. honor, at CMaua. writ at: "Ml parfwtlr read iwilim aad atria aatpler aaw pa lata th* Otmrd" For Building Radio Appa- ratus at Home THANKS to the Radio Research Lab- oratory of thoughtful Uncle Sam, three pamphlets on the construction and operation of radio receiving apparatus have been released for radio enthusiasts through the Bureau of Standards and the Government Printing Office. These sup- plementary circulars now give data and instructions on how to improve the pre- viously described sets with auxiliary ap- paratus which can be constructed at home at a small cost A limited number of the circulars are available at the Bureau. Circular 46 describes two "fixed" con- densers which are used with either of the radio receiving-sets described in the first or second circulars. One of the fixed condensers, which is connected in series with (he antenna, is called the "series- antenna" condenser. The other fixed con- denser, which is connected across the terminals of the telephone receivers, is called the "telephone-shunt" condenser. The series-antenna condenser enables the receiving equipment to give signals of somewhat greater intensity when tuned to wave frequencies above 1000 kilocycles per second — that is, wave lengths of 300 meters or less. The effect of this condenser is just the opposite of the effect obtained by a greater number of turns of wire on a tuning coil, which permits the receiving equipment to re- spond to lower wave-frequencies. The effect of the telephone-shunt con- denser is to increase the intensity of some radio signals to which the receiving set may be tuned. In most cases the use of this condenser has no effect upon the intensity of signals which are re- ceived from a radiotelephone transmit- ting station, but it will increase the in- tensity of radio signals which are re- ceived from most spark transmitting sta- tions. The cost of building both con- densers is not over 80 cents. Circular 47 describes a loading coil which is used in conjunction with the single-circuit radio receiving set de- scribed in Bureau of Standards Circular No. 120 or with the two-circuit set de- scribed in Circular No. 121. The purpose of the loading coil is to enable the receiving equipment to re- spond to wave frequencies between 100 and 500 kilocycles per second — that is wave lengths between 300 and 600 me- ters. In other words, the loading coil increases the wave-frequency (wave length) range of the receiving set The receiving set described in Bureau of Standards Circular No. 120 has a wave- frequency (wave length) range of be- tween 500 and 1500 kilocycles per second (wave lengths between 600 and 200 me- ters). The use of this loading coil will in- crease the receiving distance of the equip- ment, because many stations using the ower wave-frequencies (longer wave- lengths) use a high-power radio trans- mitting set. For example, NAA, Arling- ton, Virginia, uses a wave frequency of about 113 kilocycles per second (2650 meters wave length) and uses sufficient P°*er.,to be heard a distance of about 2»0 miles when the loading coil described is used with the receiving equipment previously described. The cost of the parts for the loading coil is approxi- mately $3. Reliable and Beautiful RADIO -A RE-CHARGER 4 THE RADIO-A is a highly efficient dependable piece of apparatus, absolutely fool- proof, easily attached by sim- ply plugging into ordinary 110 • volt lamp socket. In case of current failure, the unit cuts out automatically until current is resumed, without discharg- ing battery. It is designed expressly for re-charging radio filament bat- teries, but may be used for automobile or any other stor- age battery of reasonable size and capacity. Price, $18.50 Dealers and Distributors Herr'e a Winner! Writ* up for full particulars. 110 ...it _ the terminals te rear te A rampart portable Box- harp-lop; Tall thai will fully rharp' a 100 A. II. Bat- ter* o*ernl*-ht. for from Sc •„ 10c. n> rordlnc to prrralllnp rale*. LAST A LIFETIME King Electric Mfg. Co., Inc. 1S81 FILLMORE AVENUE BUFFALO. N. T. Digitized by Google

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26 RADIO WORLD SSs. seek, t fsr tl.00 Tke dlsl that TOM tree. Numerals engraved oa bsrel and knob as shaped that fingers do hot Mas tnem. Thin edge with olear graduation to make oocurate reading easy. Ooooealed set aerew In metal Insert. WM not warp or chip. Finish and enamel permanent. S-lnsfe dlsl 35s l.|s«k dial Isr rkeastat eetestleeirter use.... 35s 3% -leek dlsl 71* Send stamps for literature. ALDEN - NAPIER COMPANY M WIMsw St.. Dsst. L. SerisgieM. Mas*. Answers to Readers Come to Must sacrifice established WHOLESALE RADIO busi- ness. Controls exclusive sales agencies. Write Mr. Clay, 920 Chapman Bldg., Los Angeles, Cal. /AM building a set with a crystal detector. May I use enameled wire on my tuner and tapsf Has enameled wire insulating qualities'— Eugene Martens, Glen Cove, Long Island, N. Y. You can use No. 22 enameled wire very nicely for the winding of your tuner and taps. ♦ ♦ * Will I hear Newark, Pittsburgh, and Schenectady with the enclosed hook-uf and apparatus as listed?— Yearle Travis, Tucka- hoe, N.Y. Your hook-up is almost completly use- less. You will not be able to hear anything with it as it is shown. Our best advice is that you read carefully the article by C White, '••Constructing a Radio-Frequency Regenerator," in Radio World, Vol. II, No. 2, dated October 7. This circuit applies to your ideas. * • * * How far can I receive with a De Forest receiver, type DL-800, with two-stage amplifier r What length should my antenna be and in what direction should it be run to get best results? Will another stage of amplification enable me to receive further? METRO JACKS Nickel sUrer spring, coin silver contact points, all insulation Is high grmOm bakdltw. High class) finish, made to S sleesi No. 1-Stegto Open IMS No. 4-9 Sprint FlUmsnt Control. No. X-3ta«W Circuit M No. t-t Sprit* Filament Control Ho. > — Double M We also make regular V. T. Sookete with fibre and moulded bate. US "METRO SOCKETS" Isr Wattles sense Asrlstrsa I Vs eslt dry sell Mo. This asskst Is ssrfesthf flalshsd us- Isi • 2" moots highly eel- Used moulded knee. Tkls sale Is suesertsd wltk lass, lated Use. Seringa ars of sleksl slhrsr, Isaarlsj ssrfsst Prise 60s. MOULDED BASK Slagle V. T. ssuatsrssak etottrti ....Sl.tt FIBRE BABE Slsgle V. T. Bosket. .. 10.75 Dsabls V. T. Seeket.... I.St Trlsts V. T. Seskst.... 2.2S ELECTRIC FG.CO.Ing. 121 PRINCE ST. - NEW YORK. ■ SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City. Please send me RADIO WORLD for _ months, for which please find enclosed $ SUBSCRIPTION RATES: ■ingle Copy f .13 Three Montis 1.50 Sta Months MB One Year (52 Issues) 6.00 Add «' - Year lor Foreign «r ' ••tag*. TJigiti Which should I use— 2000-oAm or 3000-ohm phones? Would two or more sets of re- ceivers have any bad effects on my ma- chine?— Arthur Walsh, Patchogue, L. I. Your first question is too broad to answer; but with a good antenna satis- factory results should be obtained. Your antenna for receiving should be one straight wire about 100 feet long. The direction should be from where the lead-in starts. One more step of amplification will increase the volume and distance of your signals, but it is hard to say just how much dis- tance this one stage will increase. You can use either the 2000 -ohm or 3,000-ohm phones ; but, remember, only one set may be used at one time. * * * Can two sets receive from the same aerial? Are all audion bulbs guaranteed to work? Where can I buy an electric solder- ing-iron? What is the price?— Radio World Reader. Two sets cannot be nsed from the same aerial unless they operate at different times; otherwise, the tuning of one set would affect the tuning of the other. I do not believe that all audions are guaranteed to work, but if you buy one of the standard makes it is quite sure to give you satisfactory results. You can buy an electrical soldering iron in any electrical or radio shop for $7. * * • Can a loud-speaker be used with a crystal detector?— John Rogers, Bedford, Mass. A loud speaker cannot be used with a crystal set. Don't try it It will not operate. At least two stages of amplifica- tion are necessary. * • » My receiving set consists of a single-wire antenna about 200 feet long, a loose coupler, two variometers, grid leak, vacuum tube and grid condenser. With this set how far should I receive? If I added a two-stage amplifier, how much further could I in- crease my range? I also have mounted on my set a shielding made of copper sheet, which has no effect on tube howling.— George Siegel, Coldwater, N. Y. With a set of this description some operators have heard the broadcasting stations over some distance, using but one tube. In your case no exact distance can be given as this is right up to the operator himself. There is no doubt in our minds that you should at least hear WGY, Schenectady, New York. From other stations near you we have had reports that the following were heard, using one tube: KDKA, Pittsburgh; WJZ, Newark, N. J.; WBZ, Springfield, Mass. The addition of a two-stage audio-frequency amplifier will make these stations louder. We suggest that you connect the copper shield to the ground connection in order to eliminate the tube howling and other noises. * • * / added a two-step amplifier to my West- inghouse receiver. Will you please tell me how I can add to the wave-length range so that I may tune, say, up to 1,500 meters? Howard Mitchell, Galveston, Texas. As the set you have is designed to do certain work, it is doubtful if you will be able to raise the wave length. You might try inserting a large single-slide tuning coil in the aerial lead before it comes to the set This, possibly, may help you a little ; but it is very doubtful. Certain sets cannot be loaded up successfully. * * * In some honeycomb coil hook-ups, the bridging condenser is connected from the positive side of the B battery to the fila- ment; in others, it is connected from the filament direct to the plate. Which is cor- (Continued on following page) Subscribe for Radio World. $6.00 s " i three mr" **» year. $3.00 six month,, il*) ,

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RADIO WORLD 27 NA-ALD V. T. tin at H69£ . BbbooooV iniiai t»u« [Im. r» ^■E ■■^aaW^ iarlli»a W tarl.ttan IB ^^■•■■■■■^^ Lnrih. !*• epei — ttyt natiu) Boetct muldxl ma re.«la. CMwIU PrwUcalUr uabraaiakkv eOajal »*»-. Mxl ■!«. with utetloc i.ol«i««t V.»*"*Tn H « bull. or "eSejhr Spicial proposition for dealer, and >obb«rf. ALDEN-N APIER CX). Cabinet Load 1 Speaker with 1 Built-in Unit Made for music lovers You can't afford to buy till you have heard SPIROLA CONCERT. You can hear it at our risk. Keep it ten days and then, if you wish you can re- turn it and your money will be returned immediately. it" "Splrola Speak." Fine hand-rubbed finish in either mahogany or dark oak with bronzed throat — a thing of beauty. Complete with special unit and cord, ready to hook up in place of your headset — no extras to buy or adjust- ments to make. At dealers or sent postpaid, carefully packed (sent C. O. D. Aia if preferred)... JplZ.OU L. H. Donnell Mfg. Co. Dept. B, Box 70 ANN ARBOR, MICHIGAN If you did not get a copy of Radio World No. 1, send us $6.00 and we will send you this paper for one year, and start it with our first issue, which will be ailed you as soon as possible after re- Answers to Readers (Continued from preceding_page)_ rtctt Can a .001 condenser be used for the primary condenser instead of a .0015 con- denser? Does choke-oil amplification elimi- nate distortion?— Raymond Finch, St. Louis. The bridging condenser may be connected in the cricuit in either way. Both circuits are correct. The primary condenser should be .001 mfd. capacity for best results. Choke-coil amplification will not eliminate distortioa Improperly adjusted circuits have more to do with it • • * Is it necessary to have an aerial running east and west in order to hear Pittsburgh and Schenectady?— Leslie Meyers, Passaic, New Jersey. It is not absolutely necessary to have an aerial running east and west in order to hear these stations. If the aerial is ex- tremely long, it may help you a little to aim the free end of the aerial toward the trans- mitting station ; but it will help very little. • * • What is the constant for the phone fixed- condenser used in connection with the Arm- strong superregenerative circuit? What site vario-coupler should be used with the superregenerative? Can ordinary dry bat- teries be used for the C battery?— Thomas Meegan, Stapleton, N. Y. The capacity of the phone condensers should be .0025 mfd. Any standard vario- coupler having a range from 150 to 600 meters. The secondary must be rewound twice the number of turns. Two flashlight batteries connected in series should be used with the first two tubes and a 22-volt bat- tery with the third tube. • * • / would like to know what a two-slide tuning coil looks like? I intend buying one of these coils and wont to know what I am purchasing. — Arthur Hanson, Phoenix, Aris. .-•Screws to Mac/own Slider- , 5 derv /f-BCD, Binding Posts of tuni n, col requ^tod by Phoenix, Arizona. Above is an illustration of a tuning coil with two slides. This is used in connection with a receiving set as a means of the in- ductance in order to establish the necessary wave-lengths needed. • • • Why must I use 120 volts or more to operate my detector tube?— Peter Gray. Duluth, Minn. Probably you have a hard tube— one with a fairly high vacuum. This is similar to a vacuum tube of the transmitter type and works best on a high voltage. However, it will not be very sensitive at best. To your personal addre..: Radio World, 1 year (52 number.), $6. Quality Radio Products DlttM'M* H CvMei a Wukl.iUa R.dl. U.rmui ] Plan Varalar, 21 ... 43 Plaai CuUMtt. Ridla Star,!, Btttaria. j.kkan ind D-ton: Writ. Ir WW Far tk. BlifMt Pr*>Mltl» la Frederick H. Pruden In B Batteries That Last For 5 Years K— 400 VOLTS Send for interesting circular Dept. B. Sidbenel Radio Equipment Mfg. Co. 1003 Jerome Are, New York City Superior Radio Product. All Partt. Receirin, Set. Com plea, and la Unita. Send lor Catalogue and Prices. Dtaltri Write for /V.aonlio* RADIO OUTFITTING CORP. !m.t. STANDARD The Latest and Most Essential Part of an Efficient Tube Set Variable Grid Leak and Micon Conderwer Obtainable in an unbroken range from Hero to 5 megohms — all inter- mediate points. Fixed capacity — .00025 M. F. Improve* your aet wonderfully by Clarifying Signals Lowering Filament Current Increasing Battery Life Eliminates Hissing Price Only $1.00 rU man St. New York City Home of Micon & Antenella WARNING TO OUR READERS! RADIO WORLD accepts subscriptions thru the American Newi Co. and its branches, the regular news trade and subscription agencies. No others have any right to solicit or to accept payment for subscriptions unless they can show a properly signed subscription authorization from this publication RADIO WORLD, 14M Broad, Clitiitiiod bin w.y. li^Y. C

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28 RADIO WORLD Complete Your Files! Technical Articles Published in Radio World to Dot* of Inductance Colls, by Fred. ver-Clrcuit Design, by O. APRIL 1. A 500-Mile Radiophone Bmployuig a S-Watt Tube, by Prank A BahnoL "Toll Mo. Ploaae. How Will Tale Bot Be- eolTeT" br E. L B: Short Cuts la 0. Rooe. Making a Short-Ware Regenerator, by Fred. Chaa. Bhlert APRIL 8. Do Ton Know Tour Receiving ■qulpment by Tain fa D. Gordon. Why a Cryatal la Oalled a Rectifier, by Wal- ter Bmmett la Radiotelephone Dependable? by O. O. Boos. Mounting Cryatala In Tour Detector, by B. L, Brandon. Storage Batteries tor Radio, by Fred. Chaa. Bhlert APRIL 18. Pint Principles of Electricity aa Applied to Radio, by John P. Miles. Your Storage Battery, by B. L Bragdon. What Makes Radio Possible, by Bdward Lia- from a Simple Reoslrer, O round Connection as Vital aa Antenna, by Prod. Chaa. Bhlert. APRIL 29. Valuable Pointers on Aerial Construction, by Bdward Llnwood. What Is Meant by Tuning, by B. L Bragdon. Radio- Frequency Amplification and Regene- ration, by Prank Armstrong. Honey-Comb Colls and Condensers, by Bd- ward Llnwood. Charging the Storage Battery, by B. L. Bragdon. How to Construct the Varioooupler, by Fred- erick J. Romford. MAT ft. The Advantages of Radio Frequency, by Harold a Potter. How to Construct, Protect and Operate a Storage Battery, by George W. May. The Beginner's Catechism, by Bdward Lin- wood. Tuning and What Is Meant by It, by Prod. Chaa. Bhlert. New Frequency Amplifier Brings Faintest Wares In Strong, by G. W. May. MAT 18. My Practical ?• Detector and Two Stage Amplifier, by Frederick J. Romford. The Prindpr tor J. Howell. Principles of Radlotelegraphy, by Wal- Beglnner's Catechism, by Bdward Lin- Rules, by Fred. by Bdward Lin- The Reason for the Loop . Aerial, by George W. May. Toning and What la Meant By It, by B. L Bragden. The wood. MAT SO. The Design of an Amateur Reoelrlng Set, by C. White. , The B Battery snd the Plate Current, by George W. May. Radio Terms at a Glance, by Fred. Chaa. Bhlert The Beginner's Catechism, by Bdward Lln- wood. Fire Undewrl tars' Bhlert MAT 27. The Beginner's Catechism, wood. How to Make Tour Own Condenser, by George W. May. Tuning as Applied to Telegraphy, by Walter J. Howell. Why the Condenser Doesn't Condense, by B. L. Bragdon. Making Signals Louder with Two-Stage Am- plifier, by George W. May. JUNE 8. The Coat of a Single-Circuit Reoslrer, by Howell W. Miller. The Beginner's Catechism, by Bdward Lln- wood. How to Compute and Build a Fixed Conden- ser, by B. L. Bragdon. Design for an Amateur's Reoelrlng Set by C. White. Simple Method of Recharging a Storage Bat- tery, by John Grayson. JTJNB 10. Radio Reoslrer for Short Wares, by George W. May. How to Filter Atmospbeiio Conditions, by C. White. The Messenger Boys of Broadcasting, by B. L Bragdon. Are You a Member of the N. 0. D. C.T by B. L. Bragdon. The Beginner's Catechism, by Edward Lln- wood. How to Construct One- and Two-Slide Toning Colls, by Oorge W. May. JTJNB 17. The Vacuum Bulb's Start In Life, by C. White. How to Select the Right Set by B. L Brag- don. The B. c'nner'i Catechism, by Bdward Lln- by s. Test Bhlert Short Wares Stanley Bryant JTJNB 24. How to Make Tour Radio Cabinets, by W. Standlford. How the Cryatal Detector la Used to the Beet Advantage, by C. J. Williams. How to Const root a Long-Ware Began ore- tlre Reeetrer, by George W. May. Tested lnrentioa of Major Armstrong Ampli- fies Set 100,000 Times, by John Kent Repairing Cracks In Hard-Rubber Storage Battery Jan. by W. 8. Standlford. The Beginner's Catechism, by JULT L Novsl Unlt-Deteotor and Amplifier, by erlok J. Rumford. Why Tou Most Use a Condenser, by a Williams. How Ware Lengths Travel, by Bhlert Radio World's Rerlsed Dictionary, by Fred. Chaa. Bhlert The Beginner's Catechism, by Bdward Lln- wood. Use of the Vacuum Tube Detector, by George W. May. JULY 8. Radio's Place In the Phenomena of Nat are, by B. U Bragdon. The Function of the Loose Coupler, by Charles H. Plath. Armstrong's Buperregeneratlro Amplifier Fully Explained, by John Kent Operating a Transatlantic- Station, by Fred, Chaa. Bhlert The Beginner's Catechism, by Bdward Lie- wood. Reducing Straya and Static, by Fred. Ghas. Bhlert JULY IB. Assembling a Detector and Two-Stage Ampli- fier, by H. S. Stanford. Combined Radio and Audio Frequene) Ampli- fication, by C. White. The Beginner's Catechism, by Bdward Lln- wood. Locating Tour Aerial, by Harold Day. Facta for Beginners, by Fred. Chaa. Bhlert JULY 22. When Tour "Morles" Come by Radio, by Stan- ley Bryant. Underlying Principles of the Vacuum Tuba, by George W. May. Practical V-T Detector Panel, by Frederick J. Romford. Rerlsed Radio Dictionary, by Fred Chaa. Bhlert The Beginner's Catechism, by Bdward Lin weed. ■ Importance of Aerials to Radiation, by C. White. JULY 20. The Vacuum Tube aa a Transmitter, by Charles H. Plath. My 20-Kllowatt Tube and Its Uses, by bring Lengmulr. Importance of the Capacity Switch, by K L Bragdon. The Troth about Lamp-Socket Aerials, by Harold R. Hart The Beginner's Catechism, by Bdward Lin- wood. AUGUST 5. How to Construct and Operate the Superregeneratlre Circuit, by John using Radio Frequency to Extend ,-~gt_ by George W. May. Things Brsry Radio Fan Mast Knew, by B. B. Hawley. Rerlsed Radio Dictionary, by Fred Charles Bhlert The Beglnner'i Catechism, by Bdward Ltai AUGUST 12. The Work of the Audio-frequency Transfei by George W. May. Practical Measurements of Capacity and In- ductance, by W. A. Dickson. Experimenting with Armstrong Circuit Pro- duces Unususl Hook-up, by Dr. 0. S. Kelly. How to Secure Perfect Regeneration, by Fred. Chaa. Ehlsrt The Beginners' Cathechlsm, by Bdward Lln- wood. AUGUST 18 How to Build a Portable Field Buzser, by Do Witt H. Thompson. Using Two Tubes for Receiving, by C. White. The Storage Battery aa an Important Factor in Radio Reception, by Donald Van Wyok WT1MayTBe °f Capaclt7 ,n * Circuit, by George The Beginner's Catechism, by Bdward Llnwood. AUGUST 2fi How to Build a Splder-Web Receiver, by Frederick J. Rumford. My Detector and One-Step Amplifier, by Fred. Chaa. Bhlert The Beginner's Catechism, by Edward Lln- wood. Hints for Fans, by C. F. Rye SBPTEMBF1R 2 generating C-W for Transmission, by C NA-ALD SMALL SPACE V. T. SOCKET Us sash, I far tl-M. by assl at lama . Speoeal proportion for sealers am* Jobbers. ALDEN-NAPIER CO. Dent U tt WOeer St, Wonders of Radio- Frequency Amplification, by H S. Potter. How to Connect the Blectiie-Llght Socket Aerial, by John Kent Practical Clronlta for Regenerating Loud Sig- nals, by O. 8. Kelly. The Beglnner'i Catechlam, by Edward Lln- wood. SEPTEMBER 9 Radio Ideas for the Amateur to Teat Oat by Carl Maason. How to Make a Practical Ware-Meter, by Frederick J. Rumford. How to make a Honey-Comb Coll with a Two- Stage Amplifier, by Fred. Chaa. Bhlert Perfect Short-Wave Radio-Preaueney AjnnU- flcatlon, by George W. May. The Beglnner'i Cathechlsm, by Bdward Lin- wood. SEPTEMBER 18. v ^-t0. ¥\ke„* Two-Tube Sunerregenerator, by Frederick J. Rumford. Methods of Amplifying Radio Signals, by B. Bradbury. Voice Distortion la Vacuum-Tube Receivers, by W. A. Dickson. ^ Charging a Battery— from a French Radlolst's Point of View, by Marlue Thoorala. Working Diagrams for Beginners. SEPTEMBER 23, 1922 P. FWMeJlerl00k"UP WOTth Te»tln« °nt. 0T Whit! Metno<* for usTbtlng Filaments, by C Why the Radio Compass la the Fighting Element of Science, by Ortherus Gordon. Complete Table of Symbols Used In Radls Reception, by Fred. Cbas. Ehlert. The Radio Primer, by Edward Llnwood Complete Method for BulldUng an Electron- Tube Detector Unit, by Expert? of the United States Bureau of Standards. SEPTEMBER 80, 1922 i„ In«,easin8 the Ware Lengths of a Receiv- ing Set, by George W. May. The Importance of the Variometer to a Re- ceiving Set by Donald Van Wyck. by CCCf" Rye nnt" °f an Amateur BadtoJst, Employing Jacks with a Two-Stage Ampli- fying Rece vor, by Fred. Chas. EhlSrt. The Passing of Poldhu, by .Arthur G. Shirt _ OCTOBER 7. Superheterodyne Receiver as Applied to the KLeots * Superresenerat'Te Circuit, by Charles by^c'whitt8 * R»<«o-Frequency Regenerator, Why the Open Antenna la Beat for the Radio Listener, by C. D. Wagoner. Canada s,ation» of United States and • B™£ Radio p««ner for the Beginner, by Lynn ' ' „ OCTOBER 14. Arth* Home"Ml,de Tub« Socket, by Gordon S. Vessels Now Guided Through Fog by New ww « Rad'o'e'egraphy, by Otherus Gordon. Van D Ck Receiver Work, by Donald ce"er?bVGeor«OCWPMayn " ShortWa" Re' byRWerC11aV^hTlerR.eCeivir Short W™ OCTOBER 21 b Imjortant^ Improvements in' Radio Receivers, ChBas SEhler°t Y°Ur Gr0und Connection, by Fred. Haltie BR5i^ar,mna„,a"ed " °" H°»e' ^ by^a^Da;6""310' H°°kUp '« **ud Si«*- Km"* Rad'° Set Ha" 1 Reliab'e Range, by John Horace Be"? °f ***** C°»»»nic».ion. by Any single copy of Radio World, be- ginning with No. 1, mailed oa receipt of $1.00. The f„ll 29 number, sent for $3.45. ~2?tUV 7 months (M numbers), or SUM for 1 year (52 numbers) and haw* your subscription start from No. 1. Radio World, 1493 Broadway, New Yot* Digitized by Google

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RADIO WORLD 29 $4 CRYSTAL SET "THE LITTLE WONDER" SUS UNMOUNTED Wonder in name and a wonder in per- formance. Cannot be equalled for the price. Catches distinctly everything broadcasted within X miles. Send {or FREE catalog, describing our "Little Wonder" set and listing radio sup- plies. GUARANTEED, TESTED CRYSTALS Galena sad »A_ Radtodte.. 4W*-" Raett-O-Plate Panala. All siasa cut to order. Holloway Electric Supply Co, Inc. SS Third Avenue New York Qty Variometers $Q.95 Varioconplers each REGULAR PRICE HM These are sUndard MOULDED in- struments which is all that Is necessary to say. Order now aa thus prices wUl bo withdrawn very shortly. Yaw saoney back if m W. A. DICKSON m E. Fort St. Here's a Saving for Your Customers The) "Suneco" Adapter enables them to use the Aeriotron WD- 11 dry cell tubes in any socket without re- wiring. Eliminates the storage battery. Send for circular W containing full description. Year customers will want this. Son Equipment Company •7 Exchange Place New York That Armstrong Circuit Be much Interest baa been displayed la the ■aerial article. "TRSTED INVENTION OF MAJOR ARMSTRONG AMPLIFIES SBT 100.000 TTMBB," by John Kent, that appeared la RADIO WORLD No. IS, dated June 24, ItSS. the publisher decided to put aside a number ef for those who .were net able ta gat this _ _ wkaa published. Copies will be *rot, paetpald. on receipt of 16c or eead la your suboerlptlen. S8.00, for oae year (S3 Issues), SS.S* six months, or 11.50 three months, and subscription will be started with the Issue coa- t-«««-g the article about Major Armstrong's AmpttBer. — RADIO WORLD, 1498 Broadway, New York. Wtst to Know All About Aerials T Smd 15 eaata tar s aapr at BAD IO WOBU>. Me. 18. dated Oat. T Tma naabar aanulna u article aa tat susllea. ear*, tlaf. sad etyle of aerials. It U tnfarmatlTe. prvtleal, and simple it Is briar aid to tho petaL It was written tw C. D. Warmer, a rams BA0I0 WORLD. I4M Sraadear. Ms* York. N. V. RADIO WORLD TTLBFHONB. BBTAMT tt»S FCBUSHBD BTBBT WKDNBSDAY fDanaJ SATDBDAT OF BAMS WBBX) ISOM PtTBUCATION oirica. 1411 BB0AOWAT. NEW TOBK. M. Y. BT HBTCrBBST BASIO PUBLICATION! COBPOBAXION BOLAMD BUSKS HBNMBBtfT, M. B. HBNNB88T. a BOLAND BUBKB HXlfKBBBT, 149* Broad**?. Now Ten 7BBD & CLABK. Manager. 1491 Broadway. Haw Tars ASSOCIATB KDITOBSl SUBSCRIPTION RATES: Fifteen amts a aspy. 16. a rear, ft.** far stx seethe. II. St far tana sjanths. Add ll.se a rear arm far psataaa ta Canada aad loratrn eoontrlaa. Baeatpt by saw sabatrlbera sf the Sat sear at BADIO WOBLD nailsd to tbea altar aaadhar la tbatr ardar. la aatnsmtli attnearteilriaanl af ibatr eubaarlptlan ardar. Adrartlataf isles on request. ■stand u aaeond-elam muom. Marah 18. 1»SS. u tha Post OSlea at Now Ton. Maw Tart, seder ths act of March t, 1ST*. IMPORTANT NOTICE t While erery possible ears la take* Is stats aorreotly samara at fast aad estates la laanalail sad (ansral written ssranat tha radto Bold, aad eeary lino prlatad Is sens m with a aoraosleos rasard for tha facta, tho pubOiher dlaelalaal aar reaponalbUlty for suUmaote rocarctat quaadana of patents, priority of clalaw, tba prapar warhlac out of tachnleal problem*, or other autn that ■ay ba prloud la rood faith and aa lufwailw fundahsd br thoaa tuppoaod ta ba tmatavthr. This statoBMnt la made In food faith and Is tare time and eontrorarar la sultan am pubUahar eunot poaobtr bare control. V.A-OU-U-M-T-U-B-E-R-E-P-A-I-R-l-N-G A _ _ „^ . „ V Mysterious Radio Metal THIS metal of mystery was discovered by Bercelius in 1817, says "The Globe," New York. It has taken a hundred and some odd years to perfect it to such an extent that it is one of the most useful and promising of substances in the hands of the scientist, inventor, and experimenter. One, F. V. Madaler, has spent the past fifteen years of his life in research work on this metal at his selenium laboratories, and he has built cells of utmost sensitivity for all types of work in which such cells may be used. It is through this man that most of the data here included was obtained. Selenium is produced in two different forms: in rods and in powder. They are of differ" ent colors — reddish brown and black. When melted it has the consistency of sealing wax, and is of shiny black. When it is in this condition, it is practically a nonconductor, but by passing through a chemical process, it will change in color and become partially conductive, and will be very sensitive to changes in light. That is, its resistance will change, in a degree depending upon the amount of light reflected on it. At first, or in the dark, the resistance of the selenium is very high, and it gradually decreases to a small fraction of this resistance as the intensity of the light increases. Dont's for Listeners DON'T fail to insulate the antenna. Don't place the lightning switch indoors. Don't listen in during a thunder storm. Don't cause interference with other sta- tions. Don't try to use a loud speaker with a crystal set. Don't run wires parallel in making up receiving sets. Don't neulect to read everything avail- able on radio. of back numbers of RADIO WORLD (Nob. 1 to IS) We wiD take orders for the first sixteen israes until the If 70*1 want these inunbers, or want yoer siaWriptkna t*> y special nmnber, let as know. RADIO WORLD CO., 1493 Broadway, New York Gty lapahlas an ami e stasia lessen faOswlaf Bssad bead. Oalmsat. UT-tSt. UT-lSl. c-stt. o-sei. M T U B E R E P A I R I N G WtST MMBSVIUA MASS. *4 V^Cl^U-M-T-U-B-E-R-E-P-A-I-R-I-N-C George H. ParaO Cev, WOT : — GENUINE Nathaniel Baldwin Phones $16.00 a Pair Do not confuse these with Master Baldwin Phones, which are net made by Nathaniel Baldwin of Salt Lake City. Electric Serrlee Engineering Co. ISA W. 47th Street M. T. OUy THEY ARE GOOD rap ant tha natal (Sat aad aU» la fee MIOA- PffONTt. Beau' - - •Umlnaled. Write for ttmUr. dralm and jobban. MCAPHONBg eaD I Baals Mies PiisaiU Oa.. 1st (. 4M agar Vert Nobody Believes Us Wh*n wa sar that our •xcluatva Vario- meter ■ and Varlocouplora, which *ra »P+ml*T Rh«^*lata . SI 15 1 ntirrakable l>!al and knob see. ; W> Pay the Pottage ! Perfection Radio Corp. of America 14S West tM Street Htm York (Sty Complete Your File of RADK S2 Weeks for (LM O WORLD

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? DEPARTMENT AT So A WORD TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department U Intended for everybody who wants quick action on short announcement a covering the buying, selling, exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that it pays to read these columns every week. Advertisers will get a I— day service here— that is, copy received for this department will appear in RAD IO WORLD on the news-stands ten days after copy reaches us. is Sc. per word (minimum of It The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. discount for 4 consecutive insertions, 15% for U consecutive insertions (3 months). a* this office ten days before publication, RADIO WORLD CO.. 14H Broadway, N. Y. C. (Phone, Bryant 47M.) words. Including addreae), U% Changes will be made in standing classified adva., if copy is received TO THE TRADE— Fixed Phone and Grid Con- •severe. Write for price list and sample. SAIXEY RADIO CO., m Eighth Ave., New York Qty. Ma " ~ ~~ ~~~ SU3 an of ring Raagansetarg, Rogers Radio I Woodworth Street, Pittsburgh, Pa, PATENTS— Electrical cases a specialty. Pro- war charges. B. P. Flahburne, Registered Patent Lawyer, Jm McOffl Bldg., Washington, D. C Exchange Jolly intereetiag letters through oar Qubl Stamp appreciated. Betty Lee, Inc. 484 Broadway, New York City. ISSUES OF RADIO WORLD from April 1 to Oct. 7 (37 nam ben) for 15c a copy, or the whole lot for S3. 15. Or send us £6.00 for one year and •tart with the first number. RADIO WORLD, M» Broadway, New York. NEWS AND GOSSIP OF THE STAGE— Send RADIO MAN, eleven years' experience in all aides of the game, capable of constructing, In- stalling, operating brosdcaiting station of any power, desires permanent connection. Go any- where. What can you offer? Evans, Monroe Pier 48. N. R., N. Y. C PATENTS Protect your invention today. Write lor 199 Illustrated Book Free. Radio, Electrical, Chemi- cal and Mechanical experts. Over 30 years' ex- perience. A. M. Wilaon. Inc. (Radio 1 ARB), lit- is Victor Building. Washington, D. C. (Successors to business established 1891 by A. M. Wuson.) Are you familiar with all the radio symbols used in the various hook-ape published in Radio World r If not. secure a copy of Radio World No. at, dated Sept. 23. In this issue waa a com- plete table of all important symbols used m radio construction and testing. Send IS cents for a copy, or $6-00 per year, and have subscription •tart with that issue. RADIO WORLD, 14H Broadway, New York Qty, N. Y. •AVE If TO H% ON ALL SUPPLIES. WE •ELL SUPPLIES ONLY. LARGEST STOCK. $1.50 Round Telephone Plug, 79c; Flat, 60c ■6.00 Arrow Variometer, $3.90. Moulded black Variometer, $475. Six Dollar Manhattan Tele- phones, $4.40. Best Quality V. Condensers with Dial, $2J5. MONEY BACK Guarantee. Include AMALGAMATED RADIO SUPPLY COMPANY, USA WILLIAM STREET, NEW YORK CITY MAIL ORDER ideas sad articles wanted. Buy outright or on royalty. Send full particulars. John O. Hofbauer, Bay tide, Long Island. SELL now set, perfect condition. Westinghousc RC Receiver, Radiotron detector and two ampli- BROADCASTING STATIONS! Letters and ad- ner tubes. Pair 2200 ohm Federal Receivers with dresses of broadcasting station to- date appeared in Radio World for Oct. 7. Sent on rec eJpt of 15c Also a broadcasting map appeared in Radio World Na 8. Sent on receipt of 15c Radio World, 1493 Broadway. N. Y. City, N. Y. FRENCH TUBES, genuine (no bootleg with French name), most sensitive end economic (Good for detectors, amplifiers, and especially for radio frequency. Will work very good on two dry cells.) Price $3.90. ATLANTIC * PACIFIC RADIO CO., 131 W. 37th St., near Bway., New Yrk. CASH FOR OLD GOLD. Platinum, Silver. Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash sent, return mail. Goods returned in ten days if you're not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. Federal plug. Set cost $160.00. First Money Order for $105.00 takes it. Express prepaid. Wesley Robinson, Jr., St. Marys, Georgia. FOR SALE— New $30.00 regenerative set with- out detector— $16.00: Two new variometers and coupler, value $15.00-$8.00; $45.00 Willard Storage battery, $20.00; Crystal set— $8.00. John Keene, Mont Clare, Pa. PATENTS— Send for form "Evidence of Con- ception" to be signed snd witnessed. Form, fee Schedule, information, free. Lancaster and Ail- wine, Patent Attorneys, 259 Ouray Bldg., Wash- ington, D. C. WESTERN ELECTRIC power Araplier, prac- tically new, complete with tubes and horn. Cost $161.00. Will sacrifice for J120.00, $30.00 down. Bal- ance, C O. D. Roscoe E. Msgee, Box 71, Lon- don, Kentucky. REGENERATIVE RECEIVER— two step ampli- fier, complete in cabinet, $35.00. C D. Lowndes, 2607 Wyhe Ave., Pittsburgh, Pa. ASTONISHING results Rokay Regenerative Hook-up without use of Variometers — variocoup- lers, switches, taps, etc ONE SINGLE CON- DENSER CONTROL ONLY. The coming re- ceiver. Simpler than a non-regenerative — Setter than any regenerative we have tested. Hook- urn, $1.00. Money Orders only. Saves you $10.00 fa building your own. With properly wound coils. $3.50 post paid. Complete receiver parte on wood base with Vacuum Tube, $8.00. Head aet and "B" Battery, $21.35, Express paid. Rokay Elec- tric Co., Ingomar, Ohio. VARIOMETERS AND VARIOCOUPLERS, S3.0S each. Can Handle any number of orders. Ralph R. Garrick, 126 North Redfield St.. Philadel- phia, Pa. MURDOCK PHONES-type 56, 3000 ohms... $5JI MURDOCK PHONES — type 56, 2000 ohms... $4J8 U. V. 200 (Detector tube) k» U. V. 201 (Amplifying tube) $5Jt Postpsid in U. S. Send 25c for 208- page radio manual and cata- logue. A. V. Gregory, 42 Broad St., Redbank, N J. DO YOU USE A CRYSTAL DETECTOR T ARE YOU MAKING A CRYSTAL RECEIVER? In- crease the efficiency of your crystal detector L00» per cent by using a "PT" Ultra-Sen satire Con- tact. Of special gauge and alloy; makes and holds a quick, ultra-sensitive, stable, adjustment. Endorsed by RADIO WORLD. Using galena, yon may pound panel or table without disturbing sen- sitivity in slightest. Proved practical on ship- board by an oldtime Marconi operator. Using a "PT" Contact on galena, Arlington (NAA) was brought in clear at 3,300 miles (below the Equa- tor); and Arlington came in loud at 2J00 miles (of Dutch Guiana). In both Instances, iiaailij ships using vacuum tubes were unable even ts hear NAA. As to stability, Cape May (WCY) was worked over 1,000 sending right through crys- tal with 2 KW spark, without affecting detector's adjustment. Replace your insensitive unstable spring or catwhisker wih a Contact which will hold its adjustment in addition to giving loader signals snd music Indispensable for use in your crystal set, regardless of make. A novice csa install. _^PT" ULTRA-SENSITIVE DETECTOR CONTACT, with instructions, twenty-five curate plnte alignment, convenleat blndlag easts and Kt-nuiiie Comlenslle Na-ald DlaL Beet W shorted pltttro unknown In this eondeaser. J,p,ri.cw.TO,.,r""!.$2:50 ,,r 3 ■'«*» Varslsr nttt dial ta $4.70 far 43 slate Prealalae. Send sumps for eomplete estates' ALDEN-NAPICR COMPANY W,„ s, 0.,. . >,riM ,a>

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RADIO WORLD ■ Orange Label Tea Special lOf Tins The choice of particular people - since 1836 You can readily appreciate that such a zestful flavor and mellow aroma is the result of three-quarters of a century of experience in the skilful blerding of choice teas. Also sold in / lb., V2 lb. and V4lb. TINS A Generous Sample will be cent on request. Address i Ridgwajrs, Inc., Department K, M Warren St, New York. IZidg&ays COLD MEDAL San Francisco 1915 GRAND PRIZE SanDiego 1916 Digitized by Google

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RADIO WORLD Again the engineers of the Radio Guild lead the field in the production of radio necessities that meet with the approval of the foremost author- ities. "Multi-Range" (Bank Wound Coupler) Passed the strict requirements of the RADIO NEWS LABORATORIES and awarded their Certificate of Merit. Pronounced by the "N. Y. Evening Mail" Laboratories as "the finest bank wound coupler produced" and awarded their Certificate of Excellence. Scientifically designed by experts, the "MULTI- RANGE" Coupler permits the easy construction of an efficient short and medium wave receiver at low cost. Wave-length Range 150 to 3,400 meters. Specifications Bakelite Tubing; green double silk covered wire, wound by hand and moisture proofed; heavy nickel- plated metal parts; convenient solder taps; 180° coupling; Litz wire rotor leads. List Price, $11.00 DEALERS: The "Multi-Range" Coupler is widely advertised. Write for special discounts. 256 W. 34th Street tlTfje ftabio #utlb, 3fat RADIO-FREQUENCY SPECIALISTS Designers and manufacturers of the VOX HUMANA, the Receiver with the Uvinf Voice. New York, N. Y. Digitized by Google

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VOLUME TWO RADIO WORLD [Entered as second-class matter, March 28, 1922, at the Post Office at New York, N. Y., under the act of March 3, 1879.] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. VoL II, No. 6. Whole No. 32 November 4, 1922 15c. per copy, $6.00 a year Radio Frequency Set Operates in Interior of Automobile THE day may arrive whan the radio seta rapohlo of receiving music dearly from distant points, will be reduced to the simplicity of one knob lor tuning; for the present, however, simplicity exists only in the Inexpensive receiving seta for the reception of radiotelephone and radiotelegraph signals, at short range. When it comes to re- ceiving sots for lour range, satisfactory results sasy bo obtained only from elaborate equipment; and the more elaborate the apparatus the greater the car* and skill required for its successful Take the simple receiving seta, for ■; there Is little or nothing to master in the way of operation. . Such sets generally have a multipoint switch to control the wave length and de toe tor. If a crystal detector is used, it aunt be accurately adjusted for the utmost eenst- rl ii ansae and this necessitates care. Of course, there are the tubes with audio-frequency and radio-frequency hook-ups. The radio-frequency type of receiver employing vacuum tubes is general use among experienced ama- for long-range reception. The loop aerial asanas in connection with euch a set. In the case of audio- frequency amplification, the amplifying is done after the signals have been passed through the detector and rectified so aa to produce audio- frequency currents, while the radio-frequency amplification of the waves are amplified before they are passed to the detector. The advantage of the radio-frequency amplifier Bee m the fact that ft amplifies only the wave and not the many Bttle Irregularities and imperfections which exist in the usual receiver and amplifier to all radio signals. Although expensive sets with big aerials had failed to get a signal, this small portable outfit using an IS- inch loop for an aerial brought in Newark and Pittsburgh so dearly that music could bo heard by persons twenty feet from the head sets. The complete set is shown in the lower picture. It t at radio- frequency with a steps of audio-frequency for ampUficatian. The loop aerial may be seen with the layout and _ home-made horn for loud signals, This sat baa been carried in this car for some tine. With it the most satisfactory results have been obtained by using radio-frequency aa a means of amplifying. The upper photograph shows a radio-frequency set sands by Peter Smaney, a Newark amateur, to operate in an automobile owned in Lavaletta, New Jersey, a town claimed by experts as ' (Both photographs C. Underwood & Underwood, N. Y.) Digitized by Google

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RADIO WORLD Detectors — and How They Work THE popularity of the receiv- ing-set has caused a great many fans and amateurs to become interested in the broader aspect of radio. Not a few are familiar with electricty and handy with tools, but a large majority of them do not even care to learn the elementary principles of the game. The layman seems to think that all that is necessary is to 'connect up the set and it will gladly do the work. This is a great thing of which to boast. Many sets will work, but it is a question whether or not a set is working to its fullest efficiency. A little experimenting along well- developed lines may enable the be- ginner to greatly improve the strength of received signals. The multiwire aerial, of course, is a waste of time and money; but the single wire cannot be beaten for receiving purposes. However, This diagram is the simplest way of show- ing a two-element tube detector. It ia the ori final Fleming invention and acts aa a rectifier in much the same way as does the crystal. the direction in which the aerial points, as well as the location, has a lot to do with the matter. The direction will not make a great dif- ference in the receiving; but, in radio receiving, the currents dealt in are so small that anything that will help in the least to make the sig- nals louder may well be looked into. The direction that the aerial should be pointed is, of course, towards the station to be received. The ground lead is another im- portant factor in the set. Some amateurs are using several grounds, such as cold-water pipe, gas pipe, radiator, and the outside private ground. All of these grounds may work well together or may not work at all. No definite rule can be By Donald Van JVyck laid down, because conditions will vary greatly with the locality. The purpose and usefulness of the detector is to convert the re- ceived current of high frequency into the direct current necessary to operate telephone receivers. Va- rious forms of detectors which ac- complish this end have been used in the past, including the original coherer, the magnetic detector the electrolytic, crystal, the vacuum tub'e detector. All of these, except the two last mentioned, have be- come obsolete. We have previously read in Radio World that the crys- tal detector makes audible the high frequencies of incoming signals be- cause it rectifies them. In other words, it allows the current to pass7 only in one direction. This recti- fied current consists of a series of pulsations which pass through the windings of the telephone receivers and cause the diaphragms to vibrate, at a frequency which, in the case of radiophone signals, would correspond with the tones of the music or voice being sent out. We have also seen that, for long-dis- tance reception, a detector having more sensitive and stable character- istics than the crystal type is very desirable. These desired features are embodied in detectors of the vacuum-tube type. When using the vacuum tube as a rectifier it must allow passage of the received alternating current in one direction and prevent the pas- sage of current in the opposite direction. To bring about this re- sult, it is obvious that something must be done- to lower the resist- ance of the tube for current flowing in one direction and keep the resist- ance high when the current tends to reverse. The two metallic parts, or electrodes, are securely sealed into the glass tube and the tube is then pumped out until it is almost entire- ly free from air. One electrode, the plate, is generally formed of thin sheet-metal, while the other, known as the filament, is made of small wire and has both ends brought out through the glass. By connecting the two ends of a bat- tery to this filament, it can be heated by the battery current to a temperature which will cause it to glow brightly. When the filament is thus heated, the space between it and the plate becomes a conducting path for the flow of current if the voltage on the plate is positive ; but the resistance is maintained to pre- vent the flow of current if the vol- tage on the plate is negative. In this way, as with the crystal, a pulsation current is produced which vibrates the telephone diaphragm and produces sound. The sensitive- ness of the vacuum tube is greatly improved by the use of a third electrode, called the grid, which is essentially a metallic screen of fine mesh. This screen is placed be- tween the plate and filament of the tube and connected into the circuit as shown. Its function is to con- trol the flow of current from the plate to the filament, through the telephone circuit. It will be seen that, besides the A battery for heating the filament, there is also a plate battery called the B battery. This is connected in series with the telephone re- ceivers so that the positive ter- The three-element vacuum tube Is shown here. The X in the circle represents the grid which makes the vacuum tube the most sensitive rectifier of radio rituals. The third element, or electrode, is the work of Dr. Lee de Forest. minal is next the plate and the neg- ative terminal is next the filament. When the battery is connected in this way,' there is a steady flow of current from the B battery through the tube. This current may be con- trolled by applying a small voltage between the grid and filament. When the voltage on the grid is negative, it has the effect of de- creasing the current in the tele- phone circuit; and when the grid voltage is positive, it allows the plate current to increase. In this way, the feeble alternating currents of an incoming signal may be ap- plied to the grid and filament and used to control the flow of direct current from the B battery through the telephone receivers. Thus the effect of the signal is multiplied through the relay action of the tube and produces considerably greater action of the telephone re- ceivers than could be obtained by simple rectification. Digitized by Google

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RADIO WORLD S Hermit Radioist of Canadian Wilds By Peter Gray THE unique circumstances and exceptional radio accomplish- ment of M. J. Caveney, a lone- ly trapper with a penchant for com- panionship by radio, should stir the admiration of all radio enthusiasts. Mr. Caveney occupies a cabin at Sandy Falls, near Timmins, Northern On- tario, Canada. He has assembled one of the most powerful radio sets. It includes a complete transmitter and a receiving layout. The accompanying photograph shows the interior of Mr. Caveney 's radio shack. To the left of the receiving set, to the right is the transmitting gear. An oscillation transformer makes it possible for Mr. Caveney to insure amateurs that he can give them sharp coupling, which, in turn, will bring sharp tuning at the receiving end. Mr. Caveney claims that with this spark transmitter, he has reached and com- municated messages to amateurs with- • in twenty-five States of the United States. This the trapper can prove by the collection of postal cards, shown in another picture. In looking over the list, most amateurs who have heard Mr. Caveney were from the eighth and ninth districts. Yet there may be read the call letters of some from the third, fourth, and fifth districts. Some very fine work of transmission, indeed ! Mr. Caveney no doubt intends to keep plastering his walls with postal cards from radio amateurs who listen in when he is using his transmitter. Probably his transmitter may be heard at a greater distance when the transatlantic tests are being made in December. If so, this would prove the importance of utilizing radio as a means of long-distance communica- tion between amateurs. Demands Radio THERE is a growing interest on the part of the Italians in American production of radio apparatus. Inquir- ies are being received both for transmit- ting apparatus to be used in broadcast- ing and for radio telephone Tecciving sets. If American manufacturers in- terested in the possibilities of the Ital- ian market for their product will send catalogues and other descriptive lit- erature to the office of the American Commercial Attache, care of the Amer- ican Embassy. Rome, such material will lie made available to all persons in- quiring. haa arol him ■ Working Right (C Underwood & Underwood.) The cabm where C J. Caveney, Canadian trapper, epends twelve month* at tha year— and it ■aha lib* this tha long winter round. But Mr Caveney la not lonesome. Hia rad o art arena nun In touch with ao much of tha reel oi tha world thai ha haa a goodly quota of c on vt nation and aatartainment whan not encaged In hia interesting occupation. Jimmy — You take this wireless receiver I just finished maVing, and go down stairs in the cellar; hold it close to your car and listen. Freddy — (after waiting in suspense for several moments in the cellar)— Aw — it'i a fake; I d'dn*t hear a thing. Jtmmy — (iood 1 That showi it's workin" right. I didn't say anything wet.. Digitized by Google

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6 RADIO WORLD One of the Most Delicate Parts of a Receiver By George W. May, R. E. Figure 1— Schematic hook-up of the vernier rheo- stat. A U the f rid circuit. B the grid of the tune. E the plate of the tuba, C the switch. D the A battery. F the rheostat. G the poten- THE detector tubes now on the market require careful attention and correct adjustment of the plate battery for satisfactory results. As a matter of fact, here are no two tubes possessing the same character- istics either in filament current or plate voltage. It is very easy to make ad- justments on the filament, since the rheostat gives very fine control of the current.. Vernier rheostats may be pur- chased. These vernier rheostats have an extra arm built on the same shaft as the regular arm, and it travels over a single fine wire tightened around the body of the instrument. This is very practical as it enables the operator to regulate the filament temperature very closely which, sometimes, is very desir- able. The high-voltage batteries may be purchased tapped; the battery should, in fact, be tapped. Changing the num- ber of cells in a B battery would change the positive potential on the plate. If the positive potenial on the plate be- came greater, it would have a greater attraction for the flying electrons in the tube; hence, in a given time, more electrons would arrive at the plate and be pumped around the circuit by the battery. Such B batteries as are used for this change of high potential are of the high-voltage type, as previously ex- plained. They have five or more brass strips on binding posts secured into the sealing compound. Each one of these cells is connected to a cell in the bat- tery. So by connecting with the differ- ent posts, different values of voltages may be obtained. Jumping from one post to another on the battery may be done by employing a clip ; but it is much more convenient and easier to put five contact points and a switch arm on the panel of the re- ceiver and so be able to vary voltage by simply turning the switch arm. Of course, this necessitates a little hard work, but it is compensated for by the ease and rapidity with which tubes may be tested to determine the relative ef- ficiency of different makes. The connections are shown herewith. Each strip on the battery is eonnected to a contact point on the panel, while the switch goes in the rest of the hook- up, as indicated. There is one interest- ing point here which must be noticed. If the switch arm is so wide, or the contact points so close together that the end of the blade touches two posts at the same time, the cell between these two posts will be short circuited. In other words, if the switch is kept in Yes, Radio Is Quite au fait! (C. Underwood & Underwood, N. Y.) The leading hotels of America now have their radio rooms, and guests bear the finest concerts. This photograph was taken in the "Radio Room" ol the Greenbrier Hotel, White Sulphur Springs, West Virginia. Harry Sadenwater, radio engineer of the General Electric Company, New York, is announcing the next number on the program; Mrs. Charles F. Thompson of Washington, O. C. and Mrs. A. N. Fay of Pittsburgh listening in. this position for more than a few min- utes, the cell will be ruined and it may be necessary to purchase a new battery. To overcome this it would be a wise stunt to insert an extra switch point in between the five regular ones ; the extra ones will not be connected with any- thing. These will simply act as spacers and be dead. Figure 2— The tapped B -battery with con- trol of voltage utilising a switch arm. As an added instrument, an A bat- tery potentiometer may be used. This- g'ives extra-fine adjustment of the tube ; but it really is not necessary ex- cept in radio-frequency amplifiers. The correct method is shown in the ac- companying sketches. The ends of the winding go directly across the 6-volt battery, while the arm is the common terminal for the input and output cir- cuits of the tube. It will be noticed that the potentiometer, notwithstanding its high resistance, acts as a drain on the battery in order to do away with this loss and to have the instrument connected only when the set is used. It is suggested that a double-throw switch be used. This cuts off the fila- ment as well the potentiometer at the same time. The use of this device is simple. Be- fore making any other adjustments, set the arm at the middle of the winding. Now proceed to experiment with the values of the other elements of the tube control, get what you think are the cor- rect amounts, and then listen in. While doing so, move the potentiometer arm slowly either way until signal strength is secured. Recember that the action- of the B battery may be compared to a pump. When it forms part of a cir- cuit, it pumps electrons out of its nega- . tive terminal and into its positive termi- nal. The flow of electrons is around the circuit. This flow is a current of electricity. It may be measured by an ammeter placed at any convenient point in the circuit. Digitized by Google

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RADIO WORLD 7 National Radio Week Has Been Set for December 23 to 30 (inclusive) Major J. Andrew White Appointed Chairman of Executive Com- mittee, Preparations and Programs to Be Planned At Once NATIONAL RADIO WEEK has been definitely set to take place from December 23 to December M (inclusive). This was decided unanimously at the meeting of radio maga- zine editors, publishers, and representatives of the radio trade, the National Radio Board of Trade, and the American Radio Exposition, held at the Bankers Club, New York, on October 24. So the idea suggested by Radio World, in its issue of Oc- tober 21, becomes an assured fact. Radio World is pleased — happy beyond expression— that National Radio Week is not to be confined to its efforts alone, but is to be — as it should be— a big, broad, national affair in which every radioist — man, woman and child may not only take active part but fed that he is am integral factor in its success. The meeting at the Bankers Club— preceded by a luncheon at which the greatest optimism in the future of radio was expressed — was presided over by L. S. Brers. Among those present were: Frank Hitchcock, Postmaster General under President Roosevelt; H. Gernsback, Editor of "Radio News"; Lawrence A Nixon, managing editor, "Radio Dealer"; Amedee 3. Casey, "American Radio Journal"; John Gillette, "Electrical Merchandising"; Austin C Lescarboura, "Scientific American"; Mr. Crosby, "Modulator"; Mr. MacAttammany, "Radio Retailer and Jobber"; Mr. Wardrop, "Radio Merchandising"; Arthur H. Lynch, "Radio Broadcast"; Kenneth B. Warner, "Q. S. T."; Mr. Henderson, "Talking Machine Journal"; Mr. Robertson, "Talking Machine World"; Mr. Miller, "Radio Digest"; Mr. Callahan, "Radio Topics"; Kenneth Payne, "Popular Science Monthly"; Roland Burke Hennessey, editor, "Radio World"; Walter Gordon Clark, Harold Bolster, George Brokaw Compton, Ches- ter D. Humphrey, and Messrs. Davis and Hunter, of the Na- tional Radio Chamber of Commerce. Major Whit* was appointed chairman of an executive com- mittee to take charge of the details of preparations for Na- tional Radio Week. A supplementary committee of one hundred will bo ap- pointed. The members of this committee will be published in the next issue of Radio World. So National Radio Week takes definite shape and form! The week (December 23 to 30 inclusive) was chosen not only because this is to be actually "A Radio Christmas," but be- cause it will give wider scope for broadcasting and for ama- teur transmitting. It is a week when the younger element — whose interest in radio is as keen as that of the grown-up* — will have ample time to join in the many festivities that will be planned and carried out. National Radio Week, remember, is not a local affair. It extends to every hamlet in the country. Every fan and ama- teur is expected to take part- — and particularly, for the future of radio, to interest his friends in the new science; to bring strangers into the evergrowing radio field. Watch Radio World for National Radio Week news. And let us hear from you if you have any practical suggestions that will help to make the week a history-making one. "What would you do to make National Radio Week a suc- cess?" Let us have your answer to this question. Letters commending National Radio Week continue to pour into the office of RADIO WORLD. Here are just a few of the many received. They show the trend of opinion: O. H. Caldwell, editor of "Electrical Merchandising," will give his publication's aid: Congratulations en your plan for a National Radio Weak! "Electrical Mer JyuMUsinr" will publish an announcement la Ita next lasua regarding thilnClea. It opana up Interesting opportunities. Plaaaa kaap ua In touch with any devslopmeote that take placa In your program. • • • Major General George O. Squier, Chief Signal Officer, U. S. A, will cooperate: I believe It U a vary good idea. Anything that will help to stimulate an interest in the radio art and bring about a wider diffusion of the knowledge of the art is worthy of every effort. I have no sseelne auggestlon to offer; but I shall be glad, in a general way, to cooperate In any way I can to help towards the succesa of this enterprise. • • • Major J. D. Felsenheld, Radio editor, "The Jersey man," M or- ristown, N. J-, is in line: This department wul be glad to cooperate with you to the fullest extent in putting over a big National Radio Week. If you can go through with it, the stadium stunt will suffer a total eclipse. Let ua know if we can be of any assistance. • s e Glenn Howell, Lieutenant-Commander United States Navy, says N. R. W. should accomplish results: Your suggestion for National Radio Week is believed to bo vary appropriate and, no doubt, should accomplish results which would be beneficial to the radio business and science as a whole. Should it be desirable for the Navy to take an active part In such a i elsbration. It would be necessary to consult the Secretary of the Navy. You have my beet wishes for the success of this venture. Be a National Radio Week Booster Last-Minute YI/1RED RADIO is the latest corporation to file Wits charter In Wilmington, Delaware. Ita purpose is to develop systems. The capital stock is ftfl.pM.SSSL The holding company is the Cor- poration Trust Company of America. • • • Recent modification of the rigid laws governing the installation of radio telephone and telegraph stations have made possible the installation of radio broad casing, according to Vice-Consul Edwin B. Montgomery of Montevideo. Applications are now pending which. If granted, should mean the opening of a splendid market for radiotelephone receiving apparatus In Uruguay. Application for Government sanction to estab- lish a radiotelephone system has been made by the Dal do Electric Power Company, of Nagoya, Japan, according to advices received by the De- partment of Commerce.. The company proposes to operate this system primarily for Its own convenience In connecting the various stations with its electric light and power system, but its Radio News use may be extended to the general public As at present planned the wireless system will start from Okuwa in Nagano Perfecture on the Central Japan Railway Line, from which point communica- tion will be established through Nagoya and as far as Osaka, a distance of about IS* miles. American firms interested in the possibilities of supplying equipment may obtain the name of the purchasing agents for the Deido Company la the United States from the Electrical Equipment Divi- sion, Bureau of Foreign and Domestic Commerce. • • s More About the Telephone Mystery Editor, Radio World: In your issue No. 28, dated October 7, I read the letter from Albert Lundberg, Fairdale, North Dakota, in regard to re- ceiving telephone messages from a near- by telephone line. I had a similar experience. Sometime back, a friend and myself, while experi- menting with standard regenerative re- ceiver-circuits, put in a short ground line house-telephone system so that we could compare notes on our work. By accident we discovered that we could talk to each other through the trans- mitter of the house phones and receive through the radiophones. Further ex- periments convinced us that a standard ground-telephone system would radiate sufficient induction to be received by a radio receiver (regenerative) as far as 50 feet from the receiving instrument. This experience may afford some one a chance to do some work along this line.— R. O. Nemeyer, 497 Winona Ave- nue, Pasadena, Calif. Digitized by GOO^ Ic

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8 RADIO WORLD Radio-Equipped Polar Weather- stations Sought By Washington R. Service WITH the perfection of radio communication, great prog- ress has been made in an- other science which is, perhaps, of equal value to the world at large, particularly the seafaring and agri- cultural nations. Meteorology has advanced with leaps and bounds dur- ing the past few years. Due chiefly to radio, the outposts of meteoro- logical knowledge have been pushed far afield into distant and unpopu- lated wilds where, previously, lack of communication has withheld local weather conditions from the world. Last winter, an American engi- neer, Hagbard D. I. Ekerold, spent months on a barren rock 400 miles north of Iceland, in the Arctic Ocean, as the leader of a meteoro- logical expedition backed by the Bergen Geophysical Institute. His observations were believed so im- portant to the rest of the world that an observatory was es'ablished by the Norwegian Government at Jan Mayn, this lonely spot of rock in the Arctic sea. This new northern observatory has a wireless station, so that weather observations may be broad- cast as fast as noted. Scientists hold that this, the station farthest north, is the beginning of a new epoch in the history of science, admitting that credit is due to radio. Meteorology is fast becoming an international study, for the storms *.nd weather of one country soon af- .fects the situation in another, and, to-day, the immense area covering the whole of Europe, Northern Af- rica, and the Near East, as well as the United States and Canada, is combed with great care by weather observers and their reports received at central points, abstracted and broadcast by radio daily from Wash- ington, Pans, and a few substations. Thus it has become possible for me- teorologists to obtain within twelve hours of the taking of the observa- tions, a representative meteorologi- cal situation over the greater part of the Northern Hemisphere, extend- ing from the Pacific Coast of Amer- ica to Russia and Egypt. Professor Bjerknes, of Norway, who has done much to advance our knowledge of cyclones forming in the temperate zones, holds that weather conditions there depend chiefly on the conflict between two streams of air — a cold current flow- ing southward from the north Polar regions and a warm current drifting northward from equatorial sources already well known. These air streams, he believes, meet along a wavering front in the temperate zone, and in their intermingling create those mysterious swirls in the atmosphere which are called cy- clones. To study these possibilities, he desires to establish a chain of radio-equipped observation stations near the Pole, from the records of which the tracks followed by the Polar current southward and the centers of conflict with the warm currents may be definitely deter- mined. Such a series of circumpolar meteorological posts will have more than theoretical importance when regular forecasts for the North At- lantic are required in conection with daily air flights between Europe and America, he says. This Observatory at Jan Mayn, which transmits by radio observa- tions six times daily, constitutes the first link in the chain with Spitzen- bergen. Mr. Ekerold has made a proposition to England, the United States, and Canada, to establish a third link in the Arctic chain at Baf- fin Island, on Davis Strait near Western Greenland, over a thousand miles from Jan Mayn, Iceland, and Newfoundland. This third radio station would aid materially in studying the weather in the Far North which is practically unknown. From these stations observations aiding in establishing forecasts for the Northern hemisphere and the North Atlantic trade and air routes would emanate. 19 More Broadcasters Are Licensed (Cartoon bj Lawrence I). Hinckley! TOO DEEP FOR DAD Young Amateurs "Say, father, if I hook up • five tea- thousandth-microfarad condenser on the antenna circuit, and a variometer in the plate circuit of the electron • to you think my TWELVE licenses were issued by the Department of Commerce to 360- meter broadcasters and seven to Class B Stations operating on 400 meters, as follows : Limited Comercial or Broadcasting Stations for 360 Meters. Licensed Between Oc- tober 14 and 21, 1922. WMAY— Kingshighway, Presbyterian Church, St. Louis. WNAT— Lennig Bros. Co., Philadelphia. WNAH— Manhattan Radio Supply Co., Manhattan, Kansas. WOAV — Pennsylvania National Guard, Erie, Pa. WMAW — Wahpeton Electric Co., Wahpeton, N. D. WTAW— Agricultural & Mechanical College of Texas, College Station, Texas. WPAA— Anderson & Webster Electric Co., Waco, Nebraska. "My ahort experience with radio con- vince* me that future generations have something to live for." — Sir Thomas Lipton. WNAJ— Benson Co., Chicago. WMAN— Broad Street Baptiit Church, Columbus, O. KFBV — Clarence O. Ford, Colorad* Springs, Colo. WMAX— K. & K. Radio Supply Co., Ann Arbor, Mich. WSAV— Clifford W. Vick, Radio Con- struction Co., Houston, Texas. Class B Station to Operate on Wave Length* of 400 Meters, Licensed Between Oc- tober 14 and 21, 1922. WDAF — Kansas City Star, Kansas City, Mo. WOC— Palmer School of Chiropractic Davenport, Iowa. WHB — Sweeney School Co., Kansas City, Mo. KDKA — Westinghouse Electric flt Manufacturing Co., East Pittsburgh. WSB — Atlanta Journal Co., Atlanta, Ga. WFI— Strawbridge & Clothier, Phila- delphia, Pa. WBAP — Wortham-Carter Publishing Co., The Star Telegram, Fort Worth, Texas. Digitized by Google

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RADTO WORLD 9 Keep Your Clocks Right by Radio By Carl H. Butman WASHINGTON, D. C. — Through Naval Radio broad- casts, it is now possible to set clocks and watches to standard time twice daily. At noon, and at 10 o'clock every night, the Naval radio stations at Arlington, Annapo- lis and Key West transmit radio sig- nals, indicating the exact time for the 75th meridian or standard east- ern time. The actual time is kept at and sent from the Naval Observatory in Washington, the source of standard time for the territory east of the Rocky Mountains, the chronometer and time office at the Naval Station at Mare Island, California, serving the western territory and ships off the Pacific Coast. In a deep, even-temperature vault at the Naval Observatory three Riefler clocks keep sidereal, or star time, and although they are not quite correct, it doesn't matter. They are checked by the observa- tion of certain stars as they cross the meridian, and their exact error and rates of error calculated. Hav- ing obtained the exact Washington sidereal time, a correction for the difference in longitude of Washing- ton and the 75th meridian — which is 8 minutes and about 15 seconds — is made to secure Eastern Standard time. This is kept on two trans- mitting clocks, one of which sends out the time signal to the three ra- dio transmitting-stations by means of a relay. Previously to sending the time signals, the sending clock is checked with one of the standard Riefler clocks by comparing their ticks which are recorded on a chrono- graph, wavy pen lines indicating the separate ticks. These are measured by a finely divided scale and com- pared. Determining the error, the sending clock is speeded up or slowed electrically until its ticks cor- respond exactly with the standard clock. The ticks of the transmitting clock are sent to the three trans- mitting stations by closing a switch at the observatory, but they are broadcast by radio from the three stations. Five minutes is required to send a complete time-signal, start- ing at 1 1 :55 and running to noon, and from 9 :55 to 10 p. m. The time signals consist of telegraphic dashes every second except the 29 of each minute, the 55th to 59th seconds of the first four minutes, and the 50th to 59th seconds inclusive of the last lt_. Kadel & Herbert; Radio fuw wonder how WJZ, Newark, Now Jersey, retransmits the Arlington, Virginia, tuna signal* •vary day. The time signals are received from Arlington on mis heterodyne receiver, after which they go through the empBners to the aerials. This heterodyne receiver operates on from 2St to 2SM meters. The photograph shows Raymond F. Guy, well to radio audiences as "O.GJV.," rewanemittmg the Arlington time signals. minute before the hour. Each of these blanks is caused by a missing tooth on an otherwise complete gear-wheel. Following the 59th sec- ond of the last minute, there is a long dash commencing at the begin- ning of the new hour. Listen in for NAA on 2650 meters and set your clocks then. By means of a radio receiving set at the observatory the message of ticks may be caught and recorded on a chronograph for comparison with the sending clock's record to determine the loss in transmission. It average about .09 of a second. The time signals sent from Annapo- lis on a wave length of 16,900 meters have been heard in Australia, while in the Antipodes time signals have been heard coming around the world both ways. With a receiving set it is now no excuse to say "my clock was wrong." Better Radio for Infantry Units SIGNAL Corps radio engineers are perfecting a better field-radio set for army infantry units. The present spark set, SCR 105, developed during the World War, has become practically obsolete and continuous-wave sets are desired. A board of Signal Corps officers, which met at Camp Vail, New Jersey, recently, has recommended that surplus sets such as SCR 79- A, 127 or 130 be issued to infantry regiments for training purposes until continuous-wave sets can be developed and distributed to replace the old 105s. Recently the continuous- wave sets were adopted for all Army radio communication. The old 150 sets are quenched-spark sets used for transmitting and receiving between headquarters, usually not more than five miles apart, but if an amplifier was employed by receiving stations it was useful up to about thirteen miles. The SCR 79-A, one of the sets recom- mended by the board as a temporary substitute, is a vacuum-tube set designed for transmitting undamped waves and for receiving either damped or undamped signals. The transmitter delivers about ten watts to the antenna, and the mes- sages will carry about twenty miles on waves between 500 to 1100 meters. This set was designed for use at command posts, or at headquarters, where trans- portation is available. Details of the new sets are not com- pleted, but it is understood that they have a range of about ten miles, and will be used between regiments and brigade headquarters. Radio Don'ts Don't attach ends of antenna to power or telephone poles. Don't connect a radio set direct to the electric lipht circuit. Don't forget that tickler coils are not used with crystal detector sets. Digitized by Google

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks What is a variable condenser? A VARIABLE condenser consists of a number of semicircular metal plates arranged in two sets. One set is stationary ; the other may be moved on a pivot so that both enter between the stationary plates but without touching them. All the sta- tionary plates are connected and, like- wise, the rotating plates. The plates may be o faluminum, brass, o rany other metal that retains its shape. * * * What is the function of the variable condenser? The variable condenser supplies an electrical quantity known as capacity. Radio circuits are made up of induct- ance and capacity. Tuning coils sup- ply much of the inductance while con- densers are depended on to supply the capacity. Perhaps a clearer idea of capacity would be gathered if a con- denser were to be considered as a miniature storage-battery which catches and holds the minute electrical im- pulses until there are sufficient to make an impression on the head phones. * * * How does a variable condenser store up these impulses? Strange as it may seem, it is not the metal plates in a condenser that hold the impulses, but rather the air between the plates. The impulses come in from the aerial and are transferred to the detector circuit by simple tuner, loose coupler, variometer, or vario-coupler. The sounds are made up of little trains of waves. These trains come into the metal plates of the condenser and can- not jump from one set of plates to the other. Thwarted, they are still able to strain or twist the air between the plates. This action is the same as when a piece of soft rubber is twisted in one's hands. So long as the pressure is maintained, the twist will remain; but if one hand is removed, the rubber returns to its former shape and size. In the condenser, the waves strain the air and the air holds the strain until it has stood all it possibly can. Then it "back fires," to use a common term. * * * Are other than variable condensers used in radiophone sets? Yes. There are grid condensers, fixed condensers and the by-pass con- denser. These are used in receiving sets. » * * What is the grid condenser? When a train of waves enters from the aerial through the secondary of the loose coupler or vario-coupler, the grid is affected with an alternation of posi- tive and negative waves. As previous- ly described, the flow of electrons from the filament is helped when the grid is positive, and hindered when the grid is negative. * * * What is a grid condenser made of? A few square inches of tin foil sep- arated by a good grade of waxed paper, both materials being folded several times to conserve space. Radio Terms That Puzzle Beginners NEW radio fans seem to have difficulty in understanding many of th$ technical terms con- nected with the art. In many cases, incorrect definitions are published. These frequently cause confusion, and poor results when applied to the operation of radio instruments. A few of the more important terms are herewith defined : Crystal Set. — This type of re- ceiver derives its name from the form of detector used with it. A de- tector of this sort depends for its rectifying qualities on a little crystal of one of the number of crystals, such as galena, silicon, carborundum and others. The disadvantage of the crystal is the range which it offers. It is satisfactory in a range from 15 to 20 miles. Its advantage is due to the fact that its upkeep is low— com- paratively inexpensive. For short- distance work, it gives satisfaction. Regenerative. Set. — This is the vacuum-tube set; for crystals can- not regenerate. The regenerative action depends on feeding part of the current flowing through the plate circuit back into the grid cir- cuit, thus increasing the grid current and, likewise, the current in the phones. This feed-back is accom- plished by either tuning the plate circuit, or by using a tickler coil or a coupler condenser. Lines of Force — Those invisible streams of magnetism that surround a coil of wire, such as tuning coil, loose coupler, or vario-coupler. It is these lines of force that transfer the elec- trical energy from the primary coil of a tuning device to the secondary coiL That these lines actually exist can be proved easily by laying a piece of paper on which fine iron filings have been strewn. The filings will assume positions along curved lines which lead Hour Unas of force act In a radio loose-coupler How the lines of force would affect iron filings if the metal particles were spread on a sheet of paper over a bar i from one end of the magnetized strip to the other. Although there is no metal around tuning coils except the copper wire — which is nonmagnetic — these lines of force exist. They pass out of the individual turns of the coil down through the center and around to the other side. Non-magnetic — The term applied to some common metals which are not attracted, or repulsed, by a magnet. Copper, brass, carbon, and gold are nonmagnetic metals. Radio Notes SOMETIMES it is difficult to find a sensitive spot on your crystal. Try the following plan : Take a dis- carded crystal, and pulverize it, but not very finely. Put some of this inside a metal casing and screw it into the cup of your detector. You will be surprised to note how quickly you can find a good spot. The receiver is capable of all sorts of refinement. The best way to perfect one is not to hurry the job. Some am- ateurs take months to build their sets ; but when the sets are finished, they are real ones. The secret of radio con- struction is patience. Even after the set is completed it is well to try mak- ing a few changes in the wiring pro- vided this seems necessary. Digitized by Google

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RADIO WORLD 11 Receiver for Amplifying Weak Signals By Horace Beers 'Aerial Amplifying Transformer j ■= Ground Cotaploto *chomati« diagram of a detector and two-stag*) THE regenerative type of receiver has come into very common use in the reception of both radio- phone and radiotelegraph communica- tion, and the added increase in strength of signals makes it possible for this type of receiver to catch the very weak signals from exceedingly long distances whereas with other types of receivers amplifying transformers are employed for loud signals. It is my idea that we employ the amplifying transformers in connection with a receiver of the regenerative type. This would in turn give very satis- as described in the factory results, especially to those in- terested in listening to the broadcasting stations. The accompanying illustrates a detector and a two-stage amplifier of the regenerative type. This form of receiver is unusually selective in its tuning, and requires critical adjustment in order to get the best results. The amplifier acts as a magnifier of the signals received by the detector. With each stage of amplification, the incom- ing signals are magnified many times. With this regenerative receiver, dis- tant stations may be brought in and the fan will experience for the first time the complete satisfying thrill of hearing a faint voice announce, "This is broad- casting station WOC, Davenport, Iowa," or "this is 'Atlanta Journal' station WSB." True enough, the sig- nals will be weak and they'll fade in and out as is customary with all dis- tant transmitters, but they art. there! Most every listener is gifted with patience beyond the ordinary; for it requires considerable practice before the operator is sufficiently skilled to tune in these faraway stations. It is usually necessary to become somewhat of a "night" owl as these long-distance stations cannot be picked up with just a turn of the knob. However, until WJZ and WOR "sine off" for the night, the local interference is apt to make such an attempt hopeless. In using a regeneration set, especially those who are not familiar with oscillation, a rushing sound like that of falling water is heard just at the point where the secondary and primary are tuned to the same wave-length. The broadcasting wave will nuke known its presence by a squeal, or whistle, the pitch of which may be varied at will. When this is tuned in, the primary circuit should be varied until it is as loud as it possibly can be made, then the plate and secondary cir- cuit-condensers should be readjusted sufficiently to eliminate the whistle and bring in the broadcasting clearly. Radiomen at WJZ We Hear But Never See (C Kadel ft Herbert) JiSMW H. COWAN, "A.C.N." Ms) ftl— I I* concert manager at WJZ ana Bern of the pioneer announcer*. He ha* the distinction of having announced the first radio concert ever given and the fast World's Series baseball games. He Is ZS roars old, single, and formerly was with the Metropolitan Opera RAYMOND F. GUY, "O.G-N." Mr, Coy, who is 24 year* old, and married, ha* been with WJZ since December 1, 1*21. He is one of the beet known operator* la the country— for WJZ, Newark, N. J, Is widely heard. The initials are arranged to read, if one wants to know: (O) operator, (C) Guy, (N) Newark. In the instances of Messrs. Cowan and Watt, (A) is for anouncer. JOSEPH l~ WATT, "AW .N.- Mr. Watt is In his Mth year, an particular work is to announce the many features sent out by WJZ. When you familiar voice saying, "'A. W. N or that," then you know that Mr. Watt is Hi* cheery voice has been beard, It la estimated, almost every State in the Union. Ha is a Digitized by radio announcers. XiOOQle

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12 RADIO WORLD How to Learn the Code This Winter By Ortherus Gordon RADIO WORLD has suggested since its beginning, that the newcomers in radio learn the Continental Code. That this was appreciated was made evident when it was necessary to republish the code for the benefit of those who were lacking a copy of it and were requesting the editor to supply it. In this article, I suggest the use of a practice outfit for learning code and offer an outfit that may be con- structed by the ambitious amateur at very little cost. If you are the only amateur in your community, owning such a set, you can command the interest of the other radio enthusiasts by invit- ing them over for code practice. They should bring their headsets, plug in on the buzzer, and take down the messages as you send them from your own home-made key and buz- zer. Hide or muffle the buzzer so that its sound is not audible, or put it in the next room, and you will treat your friends to actual receiv- ing conditions combined with a speed they can read and understand. The outfit I describe is, also, ideal for radio clubs wishing to organize code classes for work during the winter. Only two instruments are needed — a key and buzzer, with a dry cell for operating them. If you own a crystal set, then you already have the buzzer ; but since it is desir- able to have this practice set mount- ed on a single board, you may want to build another. Amateurs who own regenerative outfits do not use buzzers as detector tests and, there- fore, should follow the plans as they appear in this article. While definite instructions are given, it is understood that the di- mensions and other features of the drawings are not rigid by any means, The key shown is a serviceable and yet simple affair. For its lever use a 5-inch piece of #-inch solid- brass rod. This rod is drilled as Figure L Tha buxzar. Made according to Hum It will hevs a Ugh, pleasant pitch. shown in the drawing — all taps being the useful 8/32. The knob is made of wood or hard rubber. If the amateur wants a good-look- ing knob, consider the tops of ink- bottle corks. I mean the two or four-ounce bottles and not the of- fice size. The spring is made of spring brass and may be cut to suitable dimen- sions. The uprights are made of brass plate or of wood, the only requirement being that they afford a rigid fulcrum for the lever. The fulcrum pin is a brass rod passed through the lever at right angles and fitted snugly into holes in the uprights. A convenient feature of this key is the use of battery binding posts for contacts. Take the nut of any dry- cell binding post and saw it in half. This will give you the upper and lower parts of the contact. Fasten the lower part to the base of the key and the upper to the lever, as shown, and then file them flat so that a perfect contact is made when the key is pressed. Only the prin- cipal dimensions are given. The buzzer — full plans of whick are shown in Figure 2 — may be ex- plained as consisting of three parti, each part to be made separately and put together last. They are the coil, the vibrator, and the thumbscrew. The coil has a soft-iron core. In this buzzer it is 2 inches long and Y\ -inch in diameter. This core may be either a solid piece of iron or a bundle of thin iron wires; but they must be soft iron. If steel is used, it becomes permanently mag- netized and defeats the principle on which the buzzer works. The core is held firm by two wooden ends, 1 inch square and % inch thick. It is embedded in the after end, as shown, but protrudes through the forward end 1/16 of an inch. When it is rigidly set up in these supports, wind it with six or seven layers of No. 18 or 20 cotton-covered copper wire. Bring both ends out free. If you wish, give the coil a coat of shellac or cover with tape for ap- pearance sake. The vibrator is a strip of copper or brass 2 5/8 inches long by inch wide. You may use spring brass if you wish, but it is not neces- sary. One end of the vibrator is made fast to the standard while the other end is wrapped with a piece of tin. This tin is placed direct'y in line with the center line of the core, as shown in the sketch. This is necessary because an electromagnet does not attract copper or brass The thumbscrew hardly needs ex- planation. It is merely an 8/32 screw fitted into a brass standard, or support, and placed so that it is just to the side of the tin plate on the vibrator and touching it. The connections are as follows : One end of the coil goes directly to Complete schematic diagram, living the necessary dimen- sions for tha construction of • transmitting key. Far tha lever use a 9-inch piece of Vi-inch solid-brass rod. Tha knob may be of wood or hard rubber. The spring is of spring brass, and the uprights at brass plate or wood. The ful- crum rod is a large braes pin. Battery binding-posts are —ad for contact. Read the accom- panying article carefully for further detailed instructions which the amateui should follow closely. Digitized by Google

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RADIO WORLD 13 Conductive Amplifying Receiver Picks Up Long Distances DR. FRANCIS LeROY SAT- TERLEE, noted X-ray special- ist who is now devoting him- self to radio research at his laboratories, Flushing, New York, is shown in the accompanying photograph with his "inductive amplifier," a non-regenera- tive radio-receiver working on an entirely new principle. With it he has reached unusual distances, having heard from Ontario, as far south as Louisville, Kentucky, and over a sweep from Memphis to Denver. The ap- paratus has the effect of radio-fre- quency amplification without employ- ing radio-frequency bulbs and trans- formers, the receiver using only one bulb for radio-frequency detection. The signals are then amplified by two or more steps of audio frequency in the usual manner. This is the same set (Continued from preceding page) the binding post. The other end goes to the vibrator, while the se- cond binding post is connected with the thumbscrew. Figure 3 shows the hook-up for the key, buzzer, and dry cell — together with the head- pieces as they should be connected in order to hear the buzz of the in- strument loud and clear. There is no limit to the number of head- phones that may be connected to the buzzer outfit in this manner. In fact, in radio schools where the Figaro S- Hoak-np Mt with twa or teaching of code is an important part of radio work, the headphone extension is run down the center of a long table, with jacks at every chair, so that at times as many as one hundred students are listening in on what the instructor is send- ing. These instruments have been de- signed separately; but you can put them both on the same base and save binding posts. Such a set is invaluable to the amateur who is eager to learn code. By Herbert K. Dale that interested Major-General George O. Squier, Chief Signal Officer, U. S. A., who said he would give fifteen minutes to see a test of this receiver, but actually gave three hours. The novelty in Dr. Satterlee's set is the arrangement of the inductances. He uses three flat spiral-wound coils which look a great deal like a small talking-machine record. Two operate with a "butterfly" motion. The third moves through an arc between the other two, similiar to a bookmark slipped between pages of a book. Rough tuning is accomplished by a variable condenser, and thence finer tuning by the variation of the positions of the three coils. Extreme ease of manipulation and freedom from distortion are features of this set. With a 125-foot aerial, Dr. Satterlee hears distant points. The large set on left of the lower illustration shows the original set made by him. while the small set on the ex- treme right is the present-day mod- el embodying the same principles. ML (B»tow>— Origami >■■» art, aa4 (a> okumm Digitized by Google

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14 RADIO WORLD Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengths for the Busy Reader. THE possibilities of the radiotelephone as a newsgathering agency were demonstrated in a dramatic manner, recently, when "The Inquirer" was the first newspaper in Philadelphia to receive word of the disastrous fire which swept the business dis- trict of Atlanta, Georgia. Through Edwin A. Hoban, a member of "The Inquirer's" local staff, a radio enthusiast, the news came into "The Inquirer" office even before the first flash irom the Associated Press reached Philadelphia. The information came from station WSB, operated by the Atlanta "Journal," and located in that news- paper's building. The news, announced by the speaking voice instead of by the more conventional medium of the telegraph instrument, came floating through the air, a distance of approximately 760 miles. ♦ » * The Bureau of Mine* of the Department of the Interior is seriously considering the problem of equipping mines with radio apparatus for use in the event of accident. The string- ing of telephone wires is impracticable, but officials state that it would be fairly simple to equip certain distant rooms, or chambers, with crystal receiving sets so that rescue parlies could communi- cate with imprisoned miners. The real problem is to find a simple and portable transmitting set by which the miners could communi- Corkscrew Radio May Serve to Pick Up Rum Runners (C. Fotograms, N. Y.) Don't throw away that corkscrew even if the Volstead Act is in force. There still is a food reason for keeping it around the house. It can be improvised into a real radio outfit, that may do everything a radio outfit should do. This photograph shows Jack Riley with his corkscrew radio. It Is not a complete outfit, but It will serve to pick up warnings for the run Beets. Two receivers are attached to the device, which is guaranteed to pick up all radio messages within a fifteen-mile circle. It is only to attach It to a light plug or charged wire in order to hear music or bed-time stories as you drink. cate with the mouth of the mine of the outside world in the event of being injured in or imprisoned after an accident. * ' * * Several types of speaking movies, based on the principles of radio will be tried out on the New York public in the next few months. The most serious competition will be problably be- tween the General Electric Company, which is reported to be per- fecting its talking film in a studio on Long Island, and Dr. Lee de Forest, who is working with motion-picture actors and directors at a studio near this city. The General Electric talking film and the de Forest invention both consist of films in which the voice and other sounds are photographed at the edge of the motion-picture film itself. The photographed sound waves are reproduced in each case with the aid of the photographic cell. Those who have heard the Lee de Forest phono film and the General Electric talking film say they have both reached a high degree of perfection and repro- duce the human voice. * * * Rear Admiral W. H. Bullard, U. S. N, who was in charge of the nary radio service during the world war, says that fire powerful radio stations would soon be in operation in China with sufficient energy to communicate direct with San Francisco. Ad- miral Bullard says that radio will not supplant, but would supple- ment, cable lines, telegraph and telephone. * * * Great Britain is just beginning to regulate radio broadcasting. The British scheme is to have all broadcasting done by a single or- ganization which will be sanctioned by the government, operated by manufacturers of receiving sets, and financed by both. Present plans call for the establishment of eight stations in the British Isles, at London, Manchester, Birmingham, Glasgow, Cardiff, Plymouth, Newcastle and Aberdeen. * * » The Mercantile Trust Company of San Francisco has estab- lished a broadcast station on Telegraph Hill, and will broadcast financial, industrial and general business information throughout the territory west of the Rocky Mountains. * * * "Ariograms" is the name given to United States Department of Agriculture radio reports. * * * The Los Angeles "Evening Herald" is broadcasting lessons in code fifteen minutes every week day. This is the first step in the way of definite instruction by radio. The University of Cali- fornia extension division, Berkeley, is supplying a correspondence course in elementary radio. California is keeping to the fore in radio enterprise. * * * Dr. Nicholas Murray Butler, President of Columbia Univer- sity, believes that the motion picture and the radio-telephone are going to become invaluable in the educational work of the future. He lays stress, however, on the necessity for the right material being filmed or broadcast. * * * Here are three extraordinary transmission records. Two western correspondents. E. J. Conkelman, Enterprise, Oregon ; and E. M. Bacigalupi, Hillyard, Washington, reported successful re- ception of the WGY concert of September 26 and, in both cases, their reports checked up accurately with the WGY station log. Hillyard is seven and one-half miles northeast of Spokane and 2.200 miles from Schenectady. The distance has been bettered by WGY but never during the early fall. Mr. Bacigalupi reported that his reception was made on detector alone with a Grebe Cr-9 and no amplification. His time of reception was 0:15 to 6:30 p. m., Pacific time. On September 29, Private G. G. Westfall, operator at Fort Randolph, Canal Zone, Panama, 2250 miles from Schenectady, re- ported thathe had on that date heard WGY in spite of a powerful arc set which operates twenty miles away at the Balboa station. Mr. Westfall is operator at the United States Army station. His call is WNCI. This reception is the more remarkable because of the heavy static which prevails in the warmer climate of the Isthmus of Panama. Still another unusual reception is reported by J. C. Grindell. manager of the Rectifier Department of the Valley Electric Com- pany, St. Louis. Mr. Grindell reports that he heard WGY's pro- gram Friday evening, September 29. on a home-made crystal set without amplification. His aerial, he explained, is one wire 65 feet Ion? and 30 feet high. St. Louis is approximately 875 miles from Schenectady. Digitized by Google

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RADIO WORLD 15 Radio and the Woman Crystal D. Tector I CALLED at the office of Radio World, the other day, to have a little chat with the editors about National Radio Week. Friend Husband advised me not to do so. He told me that the editors are usually so busy they become ferocious and devour people on sight — that they imagine that every woman who enters a sanctum wants to sell a poem on spring — that women talk editors to death, and all that sort of chatter. Well, I didn't heed F. H.'s warning. • ♦ * I must admit that editors are just like any other type of human beings and will stand perfectly still without being hitched. They don't bite, or even bark; in fact, they seem to have all the necessary elements of kindliness that one expects to find in ordinary men. When I reached home and told this to Friend Husband, he simply laughed and inickeringly asked if I hadn't got in the wrong pew I Fancy I I found the editors of Radio W child not only willing to talk but very (We modestly delete the rest of Miss Detector's flattering comment. She is entitled to her opinions; but the power of the bine pencil must be preserved — The editors). * * * Well, I left their offices convinced that National Radio Week will be about the biggest thing in the United States this winter. The date — December 23 up to and including the 30th— could not be more satisfactory, for we will have two Saturdays during the time of the year when everyone will be on the alert for fun of some sort. And as so many of us are looking to radio to provide something new in the way of pleasure, it does seem that the prevailing slogan : 'This is a radio Christmas," is most appropriate. • • • Mother was telling me that she remembers when the auto- mobile first came into popularity. There was such a week celebrated in her home town. It wasn't a big national affair such as our National Radio Week will be; but a purely local occasion. Although there had only been about two automobiles in the town up to the time "Automobile Week" was announced, everybody got so het up over the event, ma says, there were nearly a hundred cars in the parade — and some of them were the worst looking home-made affairs imaginable. It seems that everybody who was able produced a car for that occasion, and some folks even made their own. Ma says that she will always remember "Automobile Week" at home because an old- maid sister whom the folks thought would never marry found a willing bean. * • » From the stories she tells, the spirit of the people in making that week a success must have been something wonderful And if such a spirit existed in one little town a quarter of a century ago, what must it amount to in this huge nation to- day? Personally, I am full to the brim with energy to make National Radio Week a success. I'm going to be the best little booster of them all. And I'm asking every one of my big family of readers to get right in and help me enthuse women all over the land. * * * I want you to send me suggestions. For instance : we should have an emblem, or a pin, or a hat band, or something else that can be worn that week. Who will be the first to suggest some attractive design or monogram? Who will be the first to send in an appropriate slogan? Who can think of some- thing absolutely original for that week? Who will organize a committee to get the shopkeepers busy with window displays? • * » My first suggestion is that radio parties be made a bright particular feature of the occasion. They will blend most at- tractively with the Christmas festivities — particularly as so many churches are interested in broadcasting and so many ministers are broadcasting their sermons. Why, I am told that thousands of poor people and cripples who never have a chance to attend church now thank God that radio can bring words of sacred cheer to them in their loneliness. Can't some- one suggest something unusual for these unfortunate* during National Radio Week? • * • And for the radio parties we will want all sorts of new radio dishes— dishes that are tasty and easy to make. Girls, haven't some of you a recipe for a radio pie? Can't some one think of a radio cake?— or a radio salad? If you wiD send in tome* thing along the line of edibles, I will have Friend Husband make up a radio drink. I'll promise that it will be quite in keeping with all the prevailing laws and that the recipe will be published in plenty of time for all who wish to use it • • • Here in New York the spirit of National Radio Week is al- ready apparent among radio fans. You hear h talked about already, and many plans are being made. But we want it to move westward with the sun. We want it to get so deep under the skin of every fan that he will not be content to enjoy it by himself or in the company of other fans, but will bring strangers into the vortex of things. One of its principal ob- jects is to bring new fans into the fold. And if every radioist is responsible for at least one genuine beginner, radio will receive an impetus that will help all of us. • • • Friend Husband told me at dinner, the other day, that there is a fan in the office — remember, not an amateur but a fan. F. H. says that he asked the man, in a casual sort of way, it he really cared for radio. "Care for it I" the man flared up. "Why, I wouldn't be without it" Then he went on to tell of all the wonderful pleasures that his set had brought him. This man is just one of many — but there are millions more like him who do not know what a truly satisfying pleasure maker radio really is. We want these unknowns in the ranks of radio and we are going to get as many of them as possible in the ranks during the big week. • • • Now, don't think I ant preaching or asking you to do mis- sionary work. Far from it We who know radio— we pioneer* —want to share it with those who do not know. Why, for months I heard F. H. bawl out the man next door because he would not go to the ball games — and F. H. knowa batting averages better than I know how to tune in KDKA. Finally the neighbor reluctantly consented to go with F. H. Last season you couldn't keep Mr. Neighbor away from the Polo Grounds with chains. That is the way it will be with thou- sands who don't know, to-day, whether radio is a science or a door mat. • • • I have given up largely of my space, this week, to National Radio Week. But I feel its great importance and I realize that it is going to be one big occasion. I know, too, that much de- pends on the women of radio to make it a success; because they are nearer to the little ones than the men are. And we all know that it was our boys who really made radio possible — who ignited its first impulse. Think what a combination of radio and Christmas mean to them I • * . , Let me hear from you all. Start something in toot town. Get the spirit. As our editors say : "Be a National Radio Week booster r I will keep in touch with you regarding all my plans — but you must help to swing this great radio event into one of the most national joy festivals this big bustling country of ours ever knew. How One of Our Hook- ups Worked Editor, Radio World : In regard to the cir- cuit on page 19 of Radio World (No. 30, dated October 21) issue. I tried it with one small change and brought in San Antonio. Texas, very clearly and fairly loud, using a one-step amplifier. The change made wa« the use of a variometer in place of the DL-50. I was greatly surprised by the amount of regeneration obtainable and the ease with which regeneration was controlled by the condenser which would not appear to be in the plate circuit at all. In the near future. I expect to try several long-wave hookups (l.^OO to 30 000 meters) tiding a single coil, in the hope of finding one which will tune fairly close and give good regeneration with the use of DL coils. I shall certainly try this one with larger coils, although I am afraid that the size of the condenser will limit the wave-length range to some extent. — L. J. Coleman, Sioux City, Iowa. (The hook-up referred toby Mr. Coleman Ufis tent to Rsmo World f>v Mr. W. MtHer, Southern Methodist University, .Daiias, Texas. — The editor.) Complete Year File of RADIO WORLD S2 Wook. for SMn Digitized by Google

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16 RADIO WORLD Latest Radio Events Keep (a K*M • Herbert) (AWn) This la the mysterious "Black Box" of Thomas A. Edison, photographed for the Ant Una. Through thla mysterious device he dis- covered what ha tanned "atharic farca," and which la. In ramlitr, tha wiralaaa spark <* today aa perfected by Marconi. Ethar U an hype- | medium supposed to nil all known even thoaa portiona occupied by fluids The functions assigned to ether, with the velocity of light and tha production, whan under certain atraina or subjected to cer- tain motion*— of all tha phana— ana due trie and magnetic fields of force— indie* i of any known form of (Left) Listening to a concert by radio Inalda a ateel passen- ger car traveling o»ar eurty milae an hour. Thla is a pho- tograph of the interior of the car. The experiment took place on the Broadway lim- ited of the Pennsylvania lines, running from New York to Chicago. An It-inch loop, in- stalled la aeventeei in en all-steel car was The reception was successful, broadcasting being heard dur- ing the entire trip. (Right) The ever-smitng Mr. Fairbanks has become a radio "bug." He Is talking so that many who have never heard him speak may knew what the voice of this star of the silent drama sounds like. (0. Osdsnrew * 0p-~ . M. T.I Digitized by

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RADIO WORLD 17

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18 RADIO WORLD Latest Radio Patents Edison Invents Transmitter That Will Eliminate Unnecessary Noises No. 1,42S,1». Patented, August I, M22. Patents*: Thomas A. Edison, East Orange, N. J. Ml invention," declares Mr. Edison in a description published by the United States Patent Office, "relates to transmitters, and more par- ticularly to microphone transmitters wherein the desired variations in current are produced by variations in electrical resistance caused by varying the pressure upon a quantity of granular conductive material, such as carbon, which is dis- posed between electrodes in the circuit carrying the current, preferably in a somewhat loose state, the requisite changes in pressure being effected be- tween the electrodes and the granular material by a diaphragm, or other means, to be set into vibration by sound waves such as the human voice." Practically all microphone transmitters of this type such as are now used are seriously and adversely affected by phenomena extraneous to the sounds they are designed to transmit, such, for ex- ample, as shocks, jars, vibrations, con- cussions, etc. These phenomena often Figure 1 (above) is a vertical sectional view, part- ly in elevation, of a microphone transmitter con- structed and mounted. Figure 2 is a view in front elevation, partly broken away, of the structure shown in Figure 1. create such relative movement of the conductive granules disposed between the electrodes of the microphone trans- mitter as to produce extraneous or foreign sounds, loud enough when ampli- fied to practically obliterate and render it impossible to understand or even de- tect the sounds which the microphone is intended to transmit. The principal object of Mr. Edison's invention is to produce a microphone transmitter which will be extremely sen- sitive to very weak as well as to loud sounds and at the same time to sub- stantially eliminate or prevent the pro- duction of extraneous sounds, making it possible to employ powerful amplifying devices, such as the audion, with the transmitter. * » * Operating Vacuum - Tube Circuits No. l,42s,TK. Patented, August 22, 1*22. Pat- entees Robert C Mathes, New York City, and Harry S. Read, East Orange, N. J. THE invention on which Messrs. Mathes and Read have received letters pat- ent, relates to vacuum-tube circuits, more particularly to multistage amplifier-cir- cuits in which vacuum tubes are em- ployed in the various stages. It is well known that a vacuum tube of the three-electrode type will repro- duce in amplified form in its output cir- cuit impulses impressed upon its input terminals, and that the amplified im- pulses may be impressed on the input terminals of other tubes to give any de- sired degree of amplification. When such a multistage amplifier is employed to amplify low frequency impulses, it is generally preferable to have a direct coupling instead of an inductive coupling between stages in order that the low fre- Schematic diagram of the Mathes- Read Vacuum- Tube Circuit quency impulses will be accurately re- produced by the amplifiers. But when such a direct coupling is employed con- siderable difficulty is experienced when signals are being received from pre- venting the output current of one tube from so affecting the potential applied to the control electrode of a second tube that the second tube is either blocked or has . its amplifying action destroyed on account of its control electrode becom- ing too positive or too negative. In accordance with this invention, it has been found that the operation of such a multistage amplifier-set is con- siderably improved by providing adjust- able sources of potential for the con- trol electrodes^ of the tubes, and by pro- viding switching means between the stages whereby the output current of each tube may be given its proper value by adjusting the normal source of po- tential for its _ control electrode inde- pendently of this influence of the output current of the preceding tube. New Signal Receiving System No. 1,«M». Patented, October J, U2Z, Patentees Burke Bradbury, Schenectady, N. Y. MR. BRADBURY'S invention is to provide a simple and efficient means for providing an audible indication of signals transmitted by means of radio- frequency continuous currents. The receiving station is provided with a source of audio frequency current which is associated with an electron discharge device and a detector in such a way that when no signaling currents are impressed upon the system there will be no ap- Kj Oj^S Schematic preciable flow of audio frequency cur- rent in the detector circuit. When, how- ever, a radio frequency signaling cur- rent is impressed upon the system this signaling current is modulated by means of the audio frequency source and the modulated radio frequency signaling current is transmitted to the detector circuit where it is rectified and the recti- fied current is used to produce the de- sired audible indication. Will Help Voltage No. l,4Ss,««7. Patented, October 3, 1*22. Patentee! William C, White, Schenectady, N. Y. IT has been discovered that the cur- rent which will flow through an electron-discharge device comprising an incandescent cathode and an anode en- closed in a highly evacuated envelope will, between certain limits, vary approx- imately as the 3/2 power of the applied voltage. In other words, the apparent resistance of such a device varies with the voltage applied to it. In some cases, this characteristic is objectionable; for example, when such a device is included in a .measuring circuit which comprises other resistance. In such a case the rela- tion between current and voltage in the circuit will be a complex one and a calibration will be necessary to deter- mine this relation. The object of Mr. White's invention is to overcome this disadvantage by con- structing and arranging an electron- ic I. ^2 Figure 1 shows dlagrammatically a circuit can nection. Figure 2 shows the current-voltage characteris- tics of an ordinary high-vacuum electron dis- charge device. discharge device in such a way that the .current will vary directly as the applied voltage between certain well defined limits. Digitized by Google

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RADIO WORLD 19 Answers to Readers 7 How far could you hear with the ■*■ • hook-up you have on page 7, Radio World, No. 27, dated September 30, using an aerial of four wires, each eighty feet long? 2. What size fixed-condenser do you recommend on the stopping condenser and condenser before the grid of the third tubet 3. What kind and size tubes are recom- mended for all three shown? 4. The lead from B battery to 2-circuit jack is about 22 volts. Am I correct? 5. To make a 4S-volt B battery may I connect two 22-volt batteries in series? 6. Would the addition of my honeycomb coils help any? 7. Are the two transformers the same site? 8. Will a potentiometer help? 9. What size is the grid condenser and leak? 10. What rheostats are best — the wire type or the carbon type? — F. Bruhns, Oak- land, CoL 1. Everything depends on the way a set is constructed, also the locality, erection of antenna, etc. No exact figures can be given, but there is no reason why considerable distance cannot be received. 2. Usually about .00025 mfd., but this may be omitted from this particular place in the circuit 3. The first tube is that of a UV-200 detector tube; the next two are the UV-201 amplifying tubes. Be sure to see that the detector tube is used in the first socket. 4. The B-battery voltage on the first tube is about 22 volts. 5. Yes. By connecting two 22j£-volt B batteries in series with each other you are able to secure the necessary 45 volts. 6. No. They will not help the circuit in any manner. 7. The two transformers used are the same in size. 8. A potentiometer is of no use with this particular circuit. 9. The grid leak is of 2 megohms and the grid condenser of about .00025 mfd. capacity. 10. This all depends on the radioman who is building the set. Some prefer the wire rheostats, while others like the carbon. A vernier on the detector tube will be of great value. * * * / have m receiver using duo-lateral coils, and believe I have the wrong .hook-up. Note my diagram and let me know what error I have made.—Gustav Altrock, Man- chester, Pa. 6. P S T H**k-B» rsqiMsted by Mr. Gustav Al track, Manchester, Pa. The accompanying diagram is the correct method by which you should wire your set Follow each and every connection carefully and you will get the desired result ♦ • * / am building a regenerative receiver with two variometers and a vorio-coupler. Can a dry-cell tube be used with as good results? —Vincent Delapotteries, Wichita, Wis. Certainly. Use the same circuit, merely connecting a single dry-cell to the A bat- tery terminals. * ♦ * Will you publish a diagram of a single- tube regenerative set employing three honey- comb coils?— Fred Love land, Niagara Falls, n. y. Diagram requested by Mr. Fred Falls, N. Y. Lovaland, Niagara Herewith is a schematic diagram of a three-coil regenerative circuit employing one of the coils as tickler : P is for primary, fS for secondary, and T for tickler coil. » * * May I run my aerial from a pole to and through the gable of my house, a total dis- tance of 100 feet, and then bring my lead from center of aerial?— Harry Alexander, Staten Island, N. Y. Leave your aerial an inverted L. Don't run it through the house. We advise you to experiment with it for results, but the outside aerial still holds the record for long-distance reception. * * * Please publish a hook-up of a regenera- tive circuit using three tubes, used with variometers and vario-coupler.— Kenneth H. Jones. London Mills, III. A hook-up of this circuit was published in Radio World, No. 27, dated September 30. * * * What is wrong with my set? The dia- gram is enclosed. The aerial is 100 feet long with a 70-foot lead-in. I am using a crystal detector. — Matthew Rasmus sen, Syracuse, New York. Your diagram is wrong. Connect aerial to the switch arm and the ground to the other. Then connect one side of the de- tector to one switch arm and one side of the phones to the other. Now join together the remaining posts and detector. The phones should then be shunted by the phone condenser. * • * / have an aerial plug, tuning coil, ground clamp, crystal detector, variometer, phones, and vartable condenser. What broadcasting statwn should I receive with this set?— WtUtam Bruns, Boston. Unless you have an unusual location or live within a mile or two of some broad- casting station, you are doomed to disap- pointment with the antenna pluR. The ligrnl- ing system makes a fairly good aerial for vacuum-tube sets, though for crystal sets it is practically ruined out Snbif!ibe. for Radio World. $6.00 * year. $3.00 six months, $1.50 thr^e months ^oUMessVpcxivmcri r\A(ier o * THANKSGI DINNER A^r the voice of the Outer World- THE finest of soloists and orchestras — the most interesting and amusing of speakers— all are at your service, ren- dered by the wonderful powerofMagnavoxRadio theReproducer Supreme. Until you have heard a wireless program re- produced by the Magna- vox, you cannot realize the enjoyment that radio brings to the home. R-2 Magnavox Radio with 18-inch horn: this instru- ment is intended for those who wish the utmost in amplifying power; for large audiences, dance halls, etc $85.00 R-3 Magnavox Radio w it h 1 4- inch horn : the ideal i nstru- ment for use in homes, of- fices, amateur stations, etc $45.00 Model C Magnavox Power Amplifier insures getting the largest possible power input for your Magnavox Radio. 2 stage AC-2-C . $80.00 3-stage AC-3-C . 110.00 When you purchase a Mag- navox product you possess an instrument of the highest quality and service. Magncvox products can be had of good dealers everywhere. W rite us for copy of new illus- trated booklet. THE MAGNAVOX CO. Oakland, California N. Y. Office: 370 Seventh Ave. TAGNAVOX <!Raclio c7/?e Reproducer Supreme Digitized by Google

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26 RADIO WORLD Wave Meter for Amateur Operators How to Construct the Device Which Enables You to Adjust Your Set and Comply with the Law Prepared by the United States Bureau of Standards Experts THE construction of ■ portable short-wave radio wave-motor for uao of amateur trans - mining stations is fully explained in the following article which waa carefully pre- pared by the Bureau of Standards of the United States Department of Commerce. The de- vice Is for measuring the frequency or length of radio waves. According to the Bureau of Standards, amateur radio stations in the United States at present are required by law, when transmitting, to use wave lengths not exceeding 3m meters, and, therefore, It Is important that amateur operators should have a wave meter available so that they may adjust their sets to comply with the law. The device should bo adapted to measure short wave lengths, such as 2M meters as well as other short lengths such as 3N and US meters now used for radiotelephone broadcasting. The Radiotelephony Conference which met in Washington in February, US, mended narrow bands of wavee for particular cervices, some bands being only M wide. Stations which must work within such narrow wave bands must bo provided with well-designed wave meters if they are to comply with the requirements of the law, and the design of a portable short-wave meter is a matter of of Standards experts.— The Editor. lars in which variable condensers commonly i' fail to meet these and other requirements are: 1 too thin plates, spring-supported bearings, ex- tremely close spacing of plates, vertical or lateral play of the shaft in its bearings, con- tacts made by brushes wiping on movable parts, •tops which in arresting the rotating plates shift them out of line, shifting scales or in- dices, and faulty workmanship which allows short-circuiting of the condenser at some set- tings. In general, anything that allows a ca- pacity change without a change in scale read- ing or a change in reading without a capacity change destroys the usefulness of a condens- er for wave meter purposes. Some method of shielding is desirsble to eliminate any change of condenser capacity owing to movements of surrounding bodies. The shield usually is a grounded metal case placed around the con- denser. Regarding the inductance coils: The require- ments of a wave meter coll are: (1) that its inductance be such that with the condenser used the desired range of wave frequency can be covered. (2) that its effective resistance and effective capacity be low; (3) that its in- ductance, resistance, and capacity all be con- stant. The first requirement, which has to do with the range of wave frequencies, will first be considered. It is well to restrict the part of the condenser scale used for. frequency meas- urements to the sector between 15 degrees and 170 degrees on a scale graduated in degrees,-* or between the eighth division and ninety-fifth division on a scale graduated in hundredths. Since capacity at 170 degrees or 95 hundredths will almost always be more than six times the cspacity at IS degrees or 8 hundredths, the frequency obtained with any one coil at the lower end of this region will be not less than about 2H times the frequency obtained with the same coil at the upper end. This will make It possible, with one coil, to cover the range from 3000 to 1200 kilocycles per second (100 to 250 meters) and with a second coil to cover the range from 1330 to 530 kilocycles per second (from 225 to 570 meters). Range of Wave Frequencies The following table gives the number of turns required for two single-layer inductance coils which will cover, approximately, the stat- ed ranges with each of the maximum capaci- ties indicated in the table. It will be noted that the size of the wire and the spacing be- tween turns are not specified. The inductance is nearly independent of the size of wire used, and the spacing is controlled by the number of turns and the length of the inductance coil, both of which are given. The length of the coil, as Indicated, is the length of the actual winding, not the length of the sup- porting core. Single-Layer Inductance Colli for Short-Wave Portable Wave Meter. Coil 1. — Range 8000-1200 kilncyclet per teoond (100-2H0 meters). Diameter, 10 em. (4 fetches) ; length of winding, 2.B cm. (1 inch). Maximum capacity of condenser 0.0005 microfarad 0.0007 microfarad 0.0010 microfarad A WAVE METER is a device for measur- ing the frequency, or length, of radio waves. Radio waves always travel with the same velocity. If the frequency is known, the wave length is also known. Ama- teur radio stations in the United States at present are required by law, when transmitting to use wave lengths not exceeding 200 meters. It is important, therefore, that amateur opera- tors should hsve a wave meter available so that they may adjust their transmitting sets to com- ply with the law, and it is necessary that this wave meter should be adapted to measure short wave-lengths such as 200 meters. Other compar- atively short wave-lengths, such as 360 and 485 meters, are now used for radiotelephone broad- casting, and it is important to have a wave meter which can measure these wave lengths. The Radiotelephony Conference which met in Washington, in February, recommended narrow bands of waves for particular services, some bands being only 10 meters wide. Stations which must work within such narrow bands must be provided with well-designed wave meters if they are to comply with the requirements of the law. The design of a portable short-wave meter is, therefore, a matter of importance. It is the pur- pose of this article to point out the most im- portant considerations in the design of such a wave-meter, and to describe the construction of a wave- meter suitable for the measurement of frequencies from about 3.000 kilocycles per second to 530 kilocycles per second (wave lengths from 100 to 570 meters). The parts of a wave meter are, usually, a variable condenser, a fixed inductance-coil, and a device to indicate current flow. The con- denser^ will first be considered. It will be well at the start to eliminate cer- tain large classes of Condensers unfit for use in wave meter circuits. Variable condensers employing other dielectrics than air, and con- densers whose capacities are varied by a screw to change the distance between plates, bow- ever serviceable they may be for furnishing a variable capacity, will not in general retain their calibration and are untrustworthy for use in a wave meter. This elimination leaves only air condennrrs whose capacity is varied by changing the overlapping area of parallel plates — the us- ual type of variable condenser. All condensers of this type can by no means be used in wave meters. A condenser to be used in a wave meter should have fairly heavy pistes rigidly held together with ample tie- rods and nuts, spacing washers of large di- ameter and sufficient thickness, adequate con- ical bearings, and. preferably, unimpeded ro- *- through 360 degrees of arc. Parties- Figure 3. Schematic details of wave-meter Turn page sideways whan No. of turns 16 13 11 Coil 2.— Range 13SO-B30 Mlocyclet per teoond (22R-B70 meters). Diameter, 10 em. (4 inches) ; length of winding, 6 em. (2 inches). Maximum capacity of condenser No. of turns 0.0005 microfarad 42 0.0007 microfarad 35 0.0010 microfarad 30 The second requirement stated for the coil is that the effective resistance and the effec- tive capacity be low. Low resistance is de- sirable in order to secure sharper indication of resonance. The practice of surrounding an Inductance coil with quantities of miscellan- eous insulating materia] is undesirable in any radio circuit and is especially to be avoided in the case of wave meter coils. Imperfect insulating materials so used increase not only the effective capacity but also the effective resistance of the coil. This does not mean that all types of manufactured insulating ma- terials are unsuitable for use in frames for wave meter coils. Probably, however, the best form on which to wind the coil of a wave meter like that here described is a hollow •pool of thoroughly dry wood lightly var- nished with an extra grade of insulating var- nish. The use of shellac is not considered advisable under any circumstances. The nse of wood having even a comparatively small moisture-content may seriously affect the ac- curacy of the wave meter. Properly selected wood is chosen in preference to manufactured insulating materials, glass, or pasteboard. Many available manufactured insulating mate- rials largely increase both the resistance and the capacity of the colL While the electrical properties of glass make it well suited for a form, it presents too great mechanical diffi- culties. Pasteboard is not rigid enough and should not be used under any circumstances. The wire used may be solid copper double cotton covered. No. 24 B At S, or larger. The wire should be lightly varnished with a sin- gle coat of an extra grade of insulating var- nish. Purther Insulation merely increases the effective resistance and capacity of the eoQ without compensating advantages. The resist-

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RADIO WORLD r— Rocky Mountain Crystals— > ■rrrn than itin^ at of m JhM/Mwtri. /eaters DHlrn CMu. *u>»t> ■ Oeaiee will ha ant, laataald.. «■ rerojpt of ISa. or ooad re y»ar aahaai IpUaai. OS 00. far aaa roar (ta laaaaa), MM eta aeooBhe, ar flJO tiree Boataa. aed oahaarlpUaa will ba atartad wHh tka taaaa aoa- tadatag Uha artlda aboat Major Araaetreag'e AgaAar.-RADIO WORLD, U8S Broadway Raw Terfc. Sobecribe dfarect or thronrb yens news oWltf. XM a year, $3.M sb month* $139 three months. Rm World, 14t3 Broadway, N. Y. C (.Continued from prtctding fag*) Care mutt be taken, however, in using the high-frequency conductor to see that an the strands are continuous and well inaulated from one another, and that every strand is joined at the terminals of the coil. H imperfect in- sulation exists between adjacent stranda, these high-resistance contacts may cause a consid- erable increaae in the power losses. Broken strands seriously increaae both the effective capacity and the resistance of the coil. The stranda mar be teated for continuity by dipping one end of the cable in mercury and joining the separate stranda at the other end auc- ceesively to a buzzer or voltmeter joined to a battery, the circuit being closed through the mercury contact. The enamel may be removed from toe ends of the separate strands' by care- fully heating the cad of the wire cable to a red heat and dipping it in alcohol. This pro- cedure makes the strands more fragile and con- sequently particular care must be exercised to avoid breaking them. A single-layer coil haa generally a lower effective capacity than a multilayer coil of the same inductance and radius. This, together with the greater preciaion with which epeci- ficationa can be fumiahed for winding eingle- layer coils, was the reason for choosing this type of coil in the table already given. Since appreciable effective capacities exist when there are parts of the circuit near each other which have comparatively large areas and which are at different potentials, it follows that the leads from the coil to the condenser should not be long or close together. An ad- ditional reaaon for having the leads short is found in the third requirement previously stated for a wave meter coil, namely, that the inductance, capacity, and resistance of the coil, including its leads, be kept constant. Long orr ' 1 tviu, BvIfL*. «*v -oj Figure x. The vava-a leads are apt to be flexible; and flexible leads, long or ahort, introduce possibilities of change in inductance, capacity and resistance which can not be compensated for by any slight ad- vantage they may give in convenience of hand- ling. The best leads are rigid metal terminals soldered to the ends of the wire and screwed to the wooden core. The position of the coil should be such that the plane of the turns of the coil is perpendicular to the condenser plates if the condenser is unshielded. This is to prevent the induced current in the coil from itself inducing eddy currents in the condenser plates. Since it is almost always desired for convenience in coupling to have the plana of the coil vertical and the condenaer platea horizontal, this matter will usually take care of itaelf. A very important precaution in giv- ing the coil permanent characteristics is to draw all the turna tight and so fasten them that, with ordinary care in handling, they will not shift. The coils may be attached to binding poata on the wave meter, so that they may be con- veniently connected or removed. Various oth- er methods of attaching may alao be uaed. The third part of the wave meter is the device which shows current flow and thus indicates resonance. If a crystal detector and telephone receivers are used, only the one- point (unilateral) connection should be em- ployed; that is. the detector and telephone re- ceivers are joined in a closed circuit, and one point of this circuit is joined to one terminal of the coil. This arrangement is sufficiently sensitive and makes the calibration of the wave meter fairly independent of the position of the telephone leads, at least so long as they sre not closely drawn across some part of the wave meter or wrapped around it. A more precise indicating device is a thermogalvano- meter^ or a radio-frequency milliammeter. Available types of thermocouple instruments are usually found more satisfactory than the ordinary expansion type of hotwire instru- ment, because they respond more quickly to changes of current. The instrument should give full scale deflection with a current of about .1 smpere. It should be able to stand a considerable overload. It ia generally inserted directly in the wave meter circuit sometimes with a shunt to keep low the resistance of the circuit. It is importsnt to note that the pres- ence of the instrument will probably modify the capacity inductance and resistsnce of the circuit, so that the wave' meter should be cali- brated with the aame instrument ia the dr- ( Continued on pafft 34) V-A-CU-U-M-T-U-B-E-R-E-P-A-I R-l-N-« c Save on 1 .50 kve 00 u Detectors A Amplifiei M T rs«J u lUnlrtni sll oructara i s siaaW runattoa Saaaaa] m* aa ma fsuewuis doted tubes, aUrail. ataore- haad. [Hfwwl A. P. Blaotnjo a»*u. Bedlam TTT-ISS. UV 101. 525 (V"'- • '•tetters Sad II. ae. The melted would etpeel la teeeln tubes, ee eerrsel. win «!•• itanlutt ettlsfemee thee yea u B E R E P A I R I N George H. Porell Co, Inc. I O WIST SOHEBVILLg. H AAA. kj V-A.C-U-U-M-T-U-B-E-R.lvP-A-I.R-I.N.O W» an Ma* !■ a poMtlflB to al«a rw- UM for vrmun M'-rlea wits hQ^m- tory naoltB. A fmniihli trial *U1 Art* atif rvUaMllty u u M T U B E R E P A I RADIO MAILING LISTS Kattb t oasatga of loasltraaoo aaaoitag taa i TRADE CIRCI I.AR ADDRRHetrNO CO. |H w ADAQja BTaggT oencAa. .1^ Cut Out This Radio World Do ajsol aWtimct— If ae try MARSH'S Varalar Va $4 CRYSTAL SET THE LITTLE WONDER" UM UNMOUNTED Wonder ia aame and a wonder ia per- formance. Cannot be equalled far the price. Catches distinctly everything broadcasted within JO miles. Send for FREE catalog, describing our "Little Wonder" set and listing radio sup- pbee. GUARANTEED. TESTED CRYSTALS 4 20c HoUoway Elactric Bg Third Aveeeee Co, lays. Maw York CHy G1THENS TRUTONE RADIO HORN—LOUD SPEAKER First one to on taa> clay trial Money back Guaraatee Retail Price S21-M law! Loud Spoeakar ass Beau pveeaaaaed the Baal au Ow eulf *n nterta It Baa a •leer true teee eHerv rwlte tee hoelil try Treeeee aed ■oeume It win otaers. tf TVJO ta I aed Tlaliui net Baa*, row mm m VIS ha reroedeu. It la mti oa a ta Oar m»i a ■ e-BaoS roerusee If eat aerrta Bv row Sillw uetta aa P\jlTyb*ter 1 %md PaeJe.i aw el* t AUTO PARTS MFG. CO. Digitized by VjOVJ^LC

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per pafe Radio Merchandisin Classified Quick- Action Advertising, 5 cents per word Telephone Bryant 4796 Radio Goods that Stand the Test New Firms and Corpora- tions (The firms and corporation* mentioned m thou columns cm be reached by commmmi eating with the attorneys, whose addresses are given whenever possible.) A Well-Constructed Variable Condenser Manufactured by Caldbeck Tool & Manu- facturing Co., Des Moines, Iowa. A WELL-DESIGNED and well-constructed 23- plate variable con denier, the capacity of which waa found to be, approximately, .0005 mfd. The construction of this condenser ia aa follows: All plates are of the best-grade even-gauge hard aluminum, and are laid out mathematically cor- rect so that the area increases with the square of the angle. , The edges are so cut as to prevent burrs. This keeps down the leakage when using it with C-W transmitters. All of the insulating bushings used in this condenser are treated in boiling beeswax to prevent the absorption of moisture. This treat- ment also makes the bushings self-lubricating. Coming Events of RADIO WORLD of all cos Keep as pasted by The editors publish news shows and expos Iti mailing full inform*. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, inclusive, 1923, George A. King, director of publicity, 417 South Dearborn Street, Chicago, OL PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to Hay, 1923. AMERICAN RADIO EXPOSITION. Grand Cen- tral Palace, New York City, December 21 to 31. Colwell ft KorbelU Fisk Building, New York City, directors of publicity. INTERNATIONAL RADIO SHOW, Madison Square Garden, New York City, November 20 to 25, inclusive. E. C Buchignani, director ol pub- licity. SOUTHEASTERN RADIO EXPOSITION, Audi- torium Armory, Atlanta, Georgia, December 4 to 9, inclusive. Co-operative Radio Sales Assn., 295 Peachtree St. Heard at the Radio Counter A Conversation Between Customer and Radio Clerk (fart III) UpMNlSHING up my set the ether night, I r noticed that the signals came In weak at times and, at other rimes, the set went absolutely rtnad. With a move or adjustment of the con* denser, or plate variometer, everything was 'Jake/ Must need a rheostat— don't you think?" "I believe your trouble lies right there." "Do you think a vernier rheostat would help the set 7" "Absolutely." "How do vernier rheostats coma, and how do they operate?" "Well, there are the different makes and types; and anyone will supply the need ef vernier con- trol "An right, then; 111 take one and try it out to-night. And, by the way, will I also need a vernier on my amplifiers?" "No— not at all. Just use one on the tube In your detector circuit." "Very well. then. I hope this will keep the signals la at all times especially when giving a concert to my friends who are on the verge of bujr'nj sets." "If you are in any more trouble, Mr. Customer, with that set of yours, come In and fire away, That's what we're here for. We are here to give v" Hrc as well aa sell you merchan" >ii. Win see you shortly." (To be continued) The condenser is nicely finished and when used with a set comprises a satisfactory receiver ready for panel mounting. It was tested out in all acts and found to stand up under all conditions. • • • "Make Your Own Variometer" Racine Radio Parts Co., Racine, Wis. A "Make Your Own Variometer" has been tested out after being assembled. By the instructions and illustrations that accompany. It will be found easy and interesting to assemble. The parts come complete. In one hook-up, it waa placed in the aerial circuit of an oscillating re- ceiver and found to have a wave-length range from 150 to 450 meters. It behaved well, without showing signs of being noisy. The rotor and •tator are wound with cotton-covered magnet wire. In construction and appearance it is very attractive, and neatly finished for panel use. Victo-Rad Radio Co., Wilmington, Del., manu- facture radio equipment, $500,000. (Colonial Char- ter Co.). Guarantee Electric Co., Atlantic City, N. J., $125,000; George P. Proffatt, Katherine B. Proffatt, Walter Hanstein, Atlantic City. Precision Instrument Co., Wilmington, $500,000. (Corporstion Service Co.) Del.; Lewis Electric Mfg. Co., Buffalo, $100,000; J. N. Lewis, E. & Yatea, R. M. Stanley. (Attor- neys, Stanley & Gidley, Buffalo.) Capital Increases Halsey Electric Service ft Contracting Co., New York City, $10,000 to $25,000. Continental Radio & Electric Corp., New York City. $30,000 to $60,000. THOSE BROKEN AND BURNED-OUT VACUUM TUBES CAN BE REPAIRED AND GUARANTEED TOO! If your dealer does not know send direct to us HARVARD RADIO LABORATORIES 165 HIGH STREET BOSTON, MASS. Tubes Returned P. P. C. O. D. Digitized by Google

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RADIO WORLD 23 Foreign Orders for American Business Men Lynn W. Meekins, New England district manager of the United States Bureau of Foreign and Commerce, broadcasting foreign inquiries from the Amrad Station of the American Research Corporation at Medford Hillside, Massachusetts. This Is the Ant office of the Department of Commerce to use tba Radio and the first station to send out foreign trade Information. "A firm m Switzerland wants to buy thousands of electric tight sockets,'* (ays radio. The next morning the bureau's office in Boston receives scores of applications from firm* throughout New England for the name and address of the Swiss Importer. This la the highest speed that foreign trade promotion has yet attained. Million - Watt Vacuum Tube May Send Human Voice Across Atlantic A MILLION-WATT vacuum tube has been developed in the General Electric reseerch laboratory, Schenectady, New York, by J. H. Payne, Jr., says "The World," New York. The huge capacity tube is a mag- netron, involving the principle of magnetic control as developed by Dr. Albert W. Hull of the laboratory. The tube is expected to be of much im- portance both in radio work and long-dis- tance power transmission. Its output is about forty amperes at 25,000 volts, and serves as a rectifier to change alternating to direct current, and also to change direct to alternating current of any frequency or to convert low frequency alternating current to high frequency. It is thought that one tube will be sufficient to carry radiotelephone signals across the Atlantic This tube consists essentially of a water-cooled cylindrical abode 30 inches long and IH inches in diameter. In the axis of the anode is a tungsten filament four-tenths of an inch in diameter and 22 inches long. This filament is excited by a current of 1300 amperes at 10.000 cycles, the filament excita- tion requiring about 20 kilowatts. The magneto field produced by this large heating current is sufficient to "cut off" the electrical current from the cathode to the anode during a portion of each half cycle of the current passing through the cathode; this action taking the place of that of the grid in the three-electrode tube. The electron current to the cathode is thus interrupted 20,- 000 times per second. By the use of properly tuned circuits this can be used for the production of high-fre- quency power radio or any other purpose. Don't expect to get loud signals with a crystal detector set while using an indoor antenna. Non-liquid Storage A- and B- Batteries THERE are now on the market A- and B- storage radiobats which incorporate a number of revolutionary new features of considerable in- terest to every radio fan. Both A and B types of these new principle- batteries contain a solid elec- trolyte which makes them absolutely nonspill. This feature will be appreciated by every radioist who has ever spilled acid from his battery on his carpet or clothes. Another interesting feature is the total absence of separators which reduces internal resistance to a minimum. The radiobat grid (the metal mesh into which is pressed the "active material," form- ing the "plate") has a double reinforced con- struction. This construction adds from 25 to 30 per cent, more actual metal per square inch. The plate is, consequently, just that much more nigged and does not buckle. This reinforced strength plus the solid electrolyte makes the use ef separators unnecessary. Due to the fact however, that the secondary reinforcing mesh in the grid does not come to the surface of the plate, there is actually more active surface per square inch of plate area. In the case of the radiobat A, this results in a battery from 25 to 30 per cent, smaller and, consequently, easier to handle than any other A battery of equal rating. The radiobat storage B is even more unusual and interesting. It ts compact— only four inches square by seven inches long— scarcely larger than a large-size dry-cell B. It has no glass jar* to break, no liquid to leak. The most notable feature is its utter noiselessness of operation. It substitutes the steady, sustained voltage characteristic of a storage battery in place of the irregular constantly dropping; voltage of a dry cell, thus eliminating all hissing and crack- ling noises with which all radio operators are familiar. Changing voltage in the plate circuit is the direct cause of most tube noises and most of what is blamed on static. Sustained voltage does away with this and results in a marvel ously clear true-tone reproduction of each word and note. The Radiobat Storage B is economical as well. It is easily rechargable at home from either AC or DC and outlasts its value in dry cell Bs on each home charge. Honeycomb Coils Suggested for Usual Wave Length Ranges By Harold Day WaveLength Primary Secondary Tickler Range Coil Coil Coil Type of Service (Meters) Cat. No. Cat No. Cat No. Condenser Amateur 145-350 DL-35 DL-25 DL-35 Series Special Amateur 305-710 DL-75 DL-50 DL-35 Series Commercial 635-1660 DL-150 DL-100 DL-75 Series Navy Calling 845-1970 DL-200 DL-150 DL-100 Series Arlington Time 1420-2850 DL-300 DL-250 DL-150 Series Navy Ship Arcs 2550-4250 DL-200 DL-300 DL-150 Parallel Navy Station Arcs . . . 4200-6300 DL-500 DL-400 DL-200 Parallel Foreign and Press . . . 6250-14500 DL-1250 DL-750 DL-400 Series Foreign and Press ...13600-21000 DL-750 DL-1250 DL-400 Parallel I Want a Radio Worker In Each Community To Work For Me My wort fits In nicely for those men and women who hare i aMn hours or Tull time st home and wish to earn from 15.00 to 140.00 weekly, depending on time you devote to 1L It Is not radio work, but I believe anyone energetic enough to Interest themselves in Radio will make an eieollent "TANGLE Y BRANCH MANAGER." to oper- ate a branch for us in P Immediate profits, furnish complete ou — , Ing up a bualness you will be proud of. Don't wait until another graape this offer, write today for literature, and make your spare hours earn. TANGLEY CO., 187 Main. Muscatine, Iowa Kjllent TiNULEV lUlAIHUIJ IV A > AUZiH, 10 0|WT- us In tbefr home. Pleasant, euy work, no canvassing. 1 No Kperienoe or apodal talents necessary We outfit, train you for the wort, and assist you in bulld- No Experience Necessary Time at Full or Spare at Heme Digitized by Google

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E4 RADIO WORLD PATENT Yoar Radio Ideas CaH •a£* 21) ALADDIN ELECTRIC COMPANY, INC COMPLETE RADIO SETS WRITE FOR PRICES. 71 Weat Broadway New York City cuit as will be used in measuring frequencies. An inexpensive indicating device and one which is satisfactory when the power output of the generating circuit is large enough, is a miniature lamp, such as a flashlight lamp, in- serted directly in the wave meter circuit. To avoid any possibility of changing the cali- bration of the wave meter, the Tamp ( should not be changetl if it can be avoided. It It must be changed, it should be replaced by one of identically the same kind. The sensitiveness of this device can be grea.ly increased by hav- ing a dry cell and a rheostat in parallel with the lamp in the wave meter circuit. By ad- SOMETHING NEW! Variable Condenser Built Right Furnished either regular or vernier Made in the most popular sizes, with aluminum plates, cast end brackets, with a 1" diameter Bakelite bushing therein. (A perfect insulator high in dielectric strength). Dealers write for discounts. Ask to see our Rheostat and Vacuum Tube Socket. LOMBARDI RADIO MFG. COMPANY 67-71 Minerva Street, Derby, Conn. P. O. Box 44 Patent Applied For ^ — — — — For CORRECT RADIO MAILING LISTS Ui THE POCKET LIST af BadU lfJA-afastanrs. Jabben sad D-^te-v ta u>« I nlud states aad i uui Issued Q/asftartr-^laaaary. Arm. July and Oeteaer. OMabat. 191S. laaoa sorrartad ta natnwsw lata. ItSI. Ctaastnad aaafas thrw dlff.raot bee-nogs — afsnufeeuirers Jebbart aad D—i.r. — aad ilpaabettflall) amusad by and tewo. and aaapss at Onaa Carnal ala I apca-sxuaateb1 !>.••• naaiaa and r F. D. PICKENS, JANESVILLE, WISCONSIN GREWOL DETECTOR $2.00 Always Set and Ready (Actual Slxe) Nothing Lrke It Nothing as Good The Orewol Dasaatar baa takan Ita paass ssasaf th. standard, natlanally advarttaad paiu. la ■ cUua by Itaalf hesaa-es It d»» wkal aa dausiar haa rat bean dSTSIepsd ta da aad 11111 eaUs at If yaar staler ssaeet assart yaa. mat It aad va will 111 yaar srsav. Year Dealer ka» Sr...k Super-SMteltive RANDEL WIRELESS CO. Sole United Statu Distributor* 9 CENTRAL AVENUE NEWARK, N. J. "TUNING IN" IE IS VERY SIMPLE WHEN YOUR SOLDERED WITH THE NEW "POST SOLDERING IRON" TO THE RIGHT TUNE IS VERY SIMPLE WHEN YOUR CONNECTIONS ARE SOLDERED WITH THE NEW (Th* Iron srttb ta. Unit) Removable SoldWtaul Tip Oesigned especially to cover every requirement lav delicate work. The amall efficient Instrument SB the market. AttadMS to any socket. Universal practical, rottr POST ELECTRIC COMPANY 'D STREET, Dfv. justing the rheostat until the temperature of the. lamp filament is raised almost to the point of illumination, it is possible to have the lamp lighted by induced currents much smaller than would otherwise be required. However, changes in the battery and rheostat will be likely to change the characteristics of the cir- cuit and hence the calibration of the wave meter. This device, therefore, should be used with caution. The wave meter may be excited by impact, that is by a source of highly damped waves having only a very few wave* in a train. The wave meter can then be used as a source of damped wavea to determine the Irequency to which a receiving aet is tuned. The busier, in series with the battery, is connected across the condenser terminals, completing its circ —when the contact is cloned— through the ductance coil of the wave meter. Not m... than four volts should be used to operate the buzzer. The busier will add to the capacity of the circuit, thereby decreasing its frequency. This decrease will be especially noticeable at the lower part of the condenser scale, where it may amount to several per cent, of the fre- quency. It can be reduced by having short, widely spaced leads to battery and buiter. If the wave meter is equipped with both a buzzer and an ammeter, or current* square, meter, the ammeter muat be so connected in the circuit that the current from the busier battery cannot pass through the ammeter. If this is not done the ammeter or current- aquare meter may be burned out by the cur- rent caused to paas through it by the busier battery. The assembling of the parts of the wave meter must be such that each part is rigidly joined to the reat of the circuit. Mounting in a box is as good a means to this end as any from the standpoint of rigidity and is superior to any in portability and in the protection af- forded to the parts. A convenient box mount- ing is shown in Figure 1. The over all dimensions are left to the con- structor since the size of the component parts will vary. The box should be substantially conatructed so thst it will stand considerable handling. The component parts are all mount- ed on a panel of rigid electrical insulating ma- terial which will not absorb moisture. This panel ia, in turn, secured to the supporting box. It is possible to use a panel ol thor- oughly dried and seasoned hard wood thor- oughly varnished with an extra grade of in- sulating varnish. Figure 1 shows one possible distribution of the component parts Attention should be giv- en to the convenience of operation and ad- vantageous wiring of the circuit to keep dis- tributed capacitiea at a low value. The most advantageous arrangement of the instruments on the panel will depend in part on the par- ticular instruments used, and the constructor should work out the best arrangement in each case. Figure 2 gives a circuit diagram showing the connections as they should appear underneath the panel. These connections should be made of No. 12 solid copper wire soldered into lugs. Where bending is necessary, sharp right an- gle benda are used. If it is desired to make a short-wave portable receiving aet. terminals for antenna and ground connections can be supplied without decreasing the value as a wave meter in any way, provided suitable care is used in handling the instrument. A wsve meter should be handled more carefully than an ordinary receiving set. If It is desired to shield the wave meter, a copper, or brasa, sheet may be permanently fixed on the under side of the panel and spaces cut in it to allow for the terminals and supports of the various units. There should be at least H of an inch clearance for the terminals. Figure 3 gives the dimensions tion of the inductance coils. The forms are turned in a lathe from oughly seasoned wood. Several coats of grade insulating varnish applied to this will be desirable in keeping low the ab tion of moisture. The proper number of turns of the correct size of wire is wound in a aingle layer in the recess provided for this purpose. A light coat of extra grade insulat- ing varnish is applied to the wire to keep it in place and to prevent moisture from chang- ing the distributed capacity of the coil. The terminals of the inductance coil are brought out through the wood form and soldered to the supporting brass terminals. The wood screws holding the coil form to the brass supports should be of brass rather than a magnetic material. It is desirable that the box be provided with a protecting cover and a carrying handle. After the wive meter has been conatructed it must be calibrated. Consideration has been given to the transmission of standard wave length signals from laboratories equipped with precision measuring apparatus. This would make it possible to determine accurately sev- eral points on the calibration curve of a wave meter without sending it to a standardizing laboratory. The carrier waves of some radio- telephone broadcasting stations may be ad- justed to some particular wave, such as 360 meters, and one point on a wave length cali- bration can thus be determined. A wave meter transported for standardization. should be parked in a wooden box large est room for three inches of excelsior. _ Digitized by Google

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RADIO WORLD 25 **coa*a>#**W ky Dmalm tor SttllmMHtr R ADIO STORES CORP. VAUAILZ CONDKNSCM- PLUOS-BBUSTANCB C1G. it fear eeaear eeeee-t earr*. iMw •>•*. I, tM WM (4tt IM Mot Vera LEE RADIO CORP'N. HadaeafleU N«w Jbht ANNOUNCES THEIR "B-r SET (Patent Ape) Med For) NEEDS NO AERIAL PRICE, $35.00 CMifM* Except "A" Batterr, KIM Writ* for Prepe* Itl— . MULTIPOINT (Patent Pendtag ) A •rathetle CRYSTAL. DKTBCTOB aenaltlva over It* entire *arf*re. BUaUnatee in detector troublee. 50% Immw to elraraeee end Tolumt. Eadoraed bj Bedlo trot* end pen Awarded cerUfleetae ef eaeellenqr. Bote a neei standard of efficiency. **rlr* postpaid, mounted j CA. Srneltlvrarwe rnaraateed J UVle Oeaiera a** Dletrlevten Qeeet* Attrattlve Dlaweatj Bl SONITK FKODltTS CORPORATION W II PARK ROW. N. Y. "MIRAD" "QaalitT Radb Priead Rigfct* IfSty vlriCTualara *.'.". ■ ■ IM Ofcaa Deoile He**! Phaaaa. IM Oh** Ma** Head (ManeT bad r*4 a Plato i 1 O mat* VariaM* ( I Detacter UmH Tero-SMp AaepMi PaU Dealer*' Saaapfc *i Abava a% OaT Miracle Radio Mfg. Co. INTUIUMAN BLDO. DALLAS. TEXAS 531 SO. DEARBORN ST, CHICAGO. Radio Services Are Deeply Appreciated RELIGIOUS services at 10:30 a. m. and 4:30 p. m. every Sunday have become a regular feature of the broad- casting program of WGY, the General Electric Company's radio broadcasting station at Schenectady, N. Y. The morn- •ing service, in every case, will consist of the entire service of one of Schenec- tady's churches, which will be connected with the transmitting equipment of the big radio station by telephone wire. The afternoon or vesper service will be con- ducted in the station studio. The expansion of WGY's program tq include Sunday has come as a result of thousands of letters from radio listeners within the station's transmitting radius. A great many of the letters were from aged people, too feeble longer to go to their churches but earnest in their desire for spiritual uplift. Among the letters were also a great many pathetic appeals from invalids, some of whom must spend their life in a single room. To such as these the deep swelling tones of the or- gan, the singing of hymns, the responsive readings, and the sermon are a real in- spiration— a boon that lifts them out of the monotony of their existence and gives them a share in the activities which have failed to touch them. Another class, and probably the most numerous, that has requested radio church-services are residents of country districts too remote from churches, or of localities where churches are closed be- cause of the scarcity or expense of a regular pastor. In one case, it is known that a little group of neighboring farmers has gathered at the home of one of thejr number who had a powerful receiving set with loud speaker, and listened in, following the scripture reading in their own Bibles, making the responses in the psalter reading and joining in the con- gregational singing. The first service sent out by WGY was from the First Methodist Episcopal Church, the Reverend Philip Frick, pas- tor. Three microphones were placed in the church, one located near the singers and the organ, the second at the pastor's reading desk, and the third in an ante- room for the announcer. Controlling switches brought any of these three mi- crophones into the circuit While wandering from one radiophone to another we often wonder what it is all about — whether anything really mat- ters after all, and, if it does matter, what are we going to do about it. Perhaps we are getting to be a radiofanatic. — "The Sun," New York. Radio Inland so deep all roaring waves are still ; So far at sea that dock lights long have died And there's no sound of any train or milt ; Across the mountains high and deserts wild ; Where arc lights flare, or candles softly glow : Past harbors where ships lie with can- vas furled; From sunrise to the twilight's afterglow Man's puny voice is heard around the world. —Walter Trumbull, in 'The Herald." New York. Althoueh the domestic demand is liffht, numerous firms in and about Berlin manu- facture radio apparatus. Curiously, vacuum tubes arc "almost unavailable." says Vice- Consul Davis. Fifty-two issues for $600. Sub. De- partment, Radio World, 1493 Broadway, N. Y. C. WflOtMf I COMC IN AMD MAR TNI CORACO RADIO CONCERT DaU». • A M. te S P. M. IM »leer. tM W. **m4 St.. *art m Ammmotm Th ' ~t*aa* b tk* radto. It a** taeuUeuaa. i *> eparat* as a taiaeria* H rwm artta far tun UferaaoW THE CORACO COMPANY, INC. tM Waat 41a* (treat He* Vert BUILD YOUR OWN Cwlm Ma. tottf frtsa bMk tor M*>. «arr ea r*4W r*»»piW*i •**] km* at taafea thjmt «*Mav» el rryrtel aa4 *arsaa>a*br/\ /y rtHhhf t»u. Waafarfal lafara. l/f |/| M*-r «*> m4 fro* MraClVU Wttfc •»-ry are*! prtaa tfet el parte pro •rtatt* ! tW sararaJ aria 4*fr1W4. Hat l ae kit a* n aata* •eat wm sMle taa» MM *e *W eeaeJaae 1* VT 1 Oatoctar mod VT I Doeecfe mm* r*. r» aa* "RADIO BUILDER" PLANS PRUt ■» MaO. Sa LIBERTY RADIO CO. tM Liberty Straa* Mum Yark C*ej H0MCHARGE YOUR RADIO BATTERY for a Nicl\e I — ERJOTABLI ■•*&• Cotrtm **4 Ma it R *H«t*iRf Rant*) ar* mhittm»4 omlj wtt*M fmm taitart a tmOf tktf|ti TW ka>I OUaJUXTUO. Un • * fciMi.M, WIJw*Kti Bsitetia *J7 pram M ip«m«»»Ti*T-i« ran. **i *r •* c~e tttt Mn-Mtoi TW HOMCHAIOn Ml i- I nil. Ha *n««l» »'■»'■' »n*i«Mrt 1 1 ill ml ImiK**. THE AUTOMATIC ELECTRICAL DEVICES U*Wa* Thb* SUM EXTRA SPECIAL GENUINE WESTERN ELECTRIC TUBES with Western Electric Bases Not Rebased Not Refilled LIMITED SUPPLY ORDER AT ONCE V. T. 1— $7.50 V. T. 2— $10.00 Sent upon receipt of money order. WM. CONNOR CO. 790 Broad St. Newark. N. ». Digitized by VjOO^lC

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RADIO WORLD REAL RADIO VALUES ORDER DIRECT AND SAVE MONEY Took over these holiday specials Regular Our Price Price Unit Audion Control Panels *r A A (Detector) t*M }3.UU Unit Audion Control Panels |A AA (Amplifier) OM 1U.UU Glaat Enclosed Crystal De- | CA tectors— less crystal 2M l.«)V 23 plate Universal Condenser, m » bakelite ends, .0005 Mfd.... AM Z.50 43 plate Universal Condenser, 4M bakelite ends, .001 Mfd.... SM O.VV 3 plate Universal Vernier Condenser, .000246 Mfd lJf) .10 Keystone Variometers, ISO- j AA 580 meters M» *.UW 6 V. 60-80 Amp. Storage Bat- ioaa teries UM Open Circuit Jack — m .33 Single Circuit Jack .75 .40 Double Circuit Jack — j. .48 Double Circuit Jack Fila- et ment Control !•*• .OO Single Circuit Jack Filament co Control L» Saturn Automatic Grip as Telephone Plug 1M .90 Ajax Socket Rheostat ZM 1.40 Dictograph Headsets, 3,000 « nA ohms SM O.UU Dictograph Loudspeakers — 2t.N 20.00 Bestone Filament Rheostat.. 1.00 .60 Bestone Variocoupler, 3 inch C TC dial, 150-600 meters S.M Oml 0 Bestone Variocoupler, 3 inch j >••, dial. 150-580 meters 7.00 4.IO Bestone Socket, metal shell, bakelite base 1.00 .10 Federal Jr. Receiving sets, « r «A Dictograph Headset SM lO.UU Everything' sent F. O. B Jersey City the same day we receive your order. Send Money by Registered Mail, Post Office or Express Money order. All Goods Guaranteed the Best There Is HOLMES RADIO PRODUCTS 999-C BERGEN AVENUE JERSEY CITY, N. J. Broadcast Bill's Radiolays By IVilliam E. Douglass (Copyright, 1922, Westinghouse Electric & Manu- facturing Company.) I'VE been to lots of parties, but the best I've ever seen wuz one we had at our place, in the barn, on Hallowe'en. I had the haymow all fixed up with punkins an' with corn an' them there fancy lanterns; when I's through you would a sworn the place wuz built fer parties. I had apples hung on strings an' some others to be bobbed fer, an' a lot of crazy things. When the folks begun arrivin', I got dressed up in a sheet — one that covered me all over, couldn't even see my feet. Then I met 'em at the doorway 'fore they climbed up in the mow, pointed out how they could get their, givin' "It don't seem to (axe her— boys} I'll UU you, she's a bear." each a little bow. Abe an' Milly were the last ones, they drove up in their new flivver, an' I guess I musta scared it; when Abe stopped I saw it shiwer. Well, us three went up together fer the party had begun. They were workin' on those apples an in general havin' fun; we had cider an' some doughnuts, an' a lot of things to eat; an those punkin pies that Min makes, let me tell you, can't be beat. We played a lot of games an' then I walked right out in front an' sez, "Each person present has to do a little stunt. If you can't sing a sqng, you 11 have to hand us out a joke. Abe Jenkins, you kin start it off, then we kin watch your smoke." Well, everything wuz goin smooth until Rebecca Vance sed if she had some music, she'd put on a ballet dance. Now Becky's eddicated— been away to school a heap, an' she kin do them dances, alm6st does 'em in her sleep. The stunt that I had planned to pull wuz with my Radio an i wuz waitin' so I'd be the headline of the show. But, when Rebecca wouldn t do her dance without a tune, I 'lowed as how my act would slip fer I would just as soon pick up some real jazz music so that she could do her bit. I thought that she wuz stallin an that she would throw a fit when she found out that I could get the "music in the air. It didn't seem to faze her— boys, 1 11 tell you she's a bear. The first piece I tuned in wuz "Stumbling," which you've heard be- fore an' so she stumbled in her dance— you ought to heard 'em roar. She'd taken sev- eral encores, an' an' we'd all quit clappin when the chap announced the band would play that tune, "Do it Again." Subscribe for Radio World, $6.00 a year, $3.00 six months, $1.50 three months. TURNEY PHONES List $6.50— Special Price S3S0 3M0 ohms Amateurs: We pay postage Perfection Radio Corp. of America 14* W. 3rd St. New York City FOR IMMEDIATE DELIVERY! 500 LOTS VARIOMETERS, Ferfert, $l.tS Net ACT AT ONCE! RE ISM AN S17 West 125th Street New York City Nobody Believes Us When we aay that our exclusive Vario- meters and Varlocouplers, which are specially wound for close tuning and hooked up according to our diagram, will listen in from New York to Kansas City. Let Us Prove It To You At Our Expense Fair enough T What do too sayT OSLAND, INC., 122 Fifth Are. NEW YORK, N. Y. Special Socket W. D. 11 Designed espeoWlJ for the new tube of the Radio Corporation which ll operated by a starts drjr cell. Special ellps of phas- phor bronze with side wipe and strong gripping action on con- tact pins. Nickel plated bind- ing •crews. Highest quality throughout. Moulded from Con- ALDEN-NAPIER COMPANY 52 Willow St. Dept. L. 8trlB|«sM, Ma k^^h TS»0»' Loud Speaker Complete with Unit The First High Grade Low Priced Laud 8 sealer Re- main, Supreme. Unequaled for Pure Natural Tone Beautiful — Compact — Powerful Beautiful cabinet type, hand rubbed mahocany or dark oak fin- ish, bronzed throat, com- plete with cord— no ex- tras to buy, $12-50 At dealers or postpaid (C. O. D. if pre- ferred). Money - back guarantee if returned in ten days. "Spirola Speaks" L. H. D0NNELL MFG. CO. STMZS. YOUR wfl dearer RADIO WORLD ts ytmr stasis Issue, we su«t*et that yt a year (II lanes) M sU aaentha, and RADIO WOULD retnUriy to year hesne - at IJMe var RAW. - , ■ . - . deHvertse ef paper whenever requested. NEWSDEALER In ardar to be sure at getting RADIO WORLD rs«nlasTt>. a either subscribe direct or through your sots- tiM three snonths. Or Instruct yeur sees Dsnlsrs wttl take staadlasj orders i Radio W

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RADIO WORLD 27 A Broadcasting Record WHAT is believed a record-distance foe daylight broadcasting was made by WGY, the General Electric Company, broadcasting station, in re- porting the recent World Series. Base- ball fans in Havana, Cuba, 1500 miles from Schenectady, reported distinct re- ception of the game of Thursday, Octo- ber 4. The series was reported, play by play, by W. O. McGeehan, sporting editor of the New York "Herald." A leased wire carried the story of the game from the press box in the Polo Grounds, New York, to the transmitting apparatus of WGY, ISO miles away. From WGY, the story traveled on Hertzian waves to listeners within hundreds of miles. Many letters and telegrams were received ex- pressing appreciation for the prompt baseball service. Fans were able to follow every play and actually visualize the game. The following cablegram was received from Havana: "Havana Life" published a front-page story which in part, states : 'The broad- casting of the World Series games by the New York Herald and WGY has made a great hit in Cuba. In was heard distinctly throughout the republic, ac- cording to reports received by 'Havana Life.' Our managing editor, Fred M. de Stefano, heard the report from the re- ceiving station of Cecil J. Dale at Marianao, near the Oriental Park Race Track. F. W. Borton, president of the Electrical Equipment Co., of Cuba, lead- ing radio fan, pays a great compliment on the clearness with which the report was received here." A Radio Newspaper A PARIS newspaper has ceased to be printed and is published orally. The subscribers meet in a hall and listen to the editors and reporters. The editorial staff has specialists who address the sub- scribers on topics of the day. So far the experiment has proved profitable. It saves the mechanical cost of publication and the white paper, says "The Globe," New York. Here is an idea that might be adopted by one of the radio stations. The main cost of a daily newspaper is not the pay of the reporters, copyreaders and editors; but the cost of the mechanical depart- ments and the white paper. By substi- tuting radio broadcasting all the type- setting, stereotyping, and printing-press machinery would be dispensed with. There would be no expensive system of distribution, such as wagons and trucks. The hundreds of tons of white paper could be left to grow into spruce trees in the forest. This may come some day; but the diffi- culty at present would be in collecting from the subscribers and in preventing anybody with a receiving apparatus from getting his daily news and editorials without paying for them. The sub- scribers would also have to go without cartoons and illustrations, unless they in- stalled the more expensive and compli- cated apparatus recently invented, by means of which pictures can be elec- trically transmitted. May — What did Noah do for laughs on his voyage in the ark with no radio to tune in on jokes from ABC and XYZ? flay — You recall that he took two of every animal known? May— Yes. Ray — Well, the hyenas were the laugh- ing stock of the ark. —"Topics of the Day" Films. Fifty-two issues for $6.00. Sub. De- partment, Radio World, 1493 Broadway, N: Y. C. The Assembly $ Detector and Tuning Unit 27- A high-grade tube set that costs less than price of parts used. Super-sharp tuning through double cir- cuit and Litz -wound rotor. A real tube set for the price of a good crystal set. All the fun of assembling — but correct assembling made absolutely certain and easy. Supplied in knock-down form, panel drilled and engraved, all parts packed inside cabinet, including connecting wires cut and bent ready for soldering. If your dealer can't supply you, send check or money order. The RADIO READING COURSE Five Books on Radio Five complete radio in- struction books, teaching the elementary Theory, De- sign, Construction, Opera- tion and Maintenance of radio apparatus. Gives yon a thorough grasp of the whole subject. Prof. J. H. MORECROFT Astooiate Editor and AdvUor No tedious study — needs only to be read. Will save you money in the purchase, construction and repair of radio apparatus. Will add a hundred-fold to your pleasure. SEND NO MONEY: The complete five books yours for only $1:97 and postage. Just send name and address and pay the postman $1:97 and postage. Send at once for your set of five books. PROGRESSIVE DEALERS AND JOBBERS Ton want thU sure-selling; Assembly Set. It meets the needs of the Merest buying class— those who want a real tube set at a low price. Attractive discounts. Order now for early delivery. Solve your book problem with the Radio Reading Coarse set of five books. A fast selling; Item. Write for discounts, and order sample copy. RADIO COURSES, INC. (Dept. RW3), 552 Seventh Avenue, New York MASTER BALDWIN PHONES AN IMPROVEMENT ON WHAT WAS CONSIDERED THE BEST Those who know. In the radio world, have always used the Baldwin Phone. It has been lull »n— ill where enacting work wu to be done. It was oonoeded to be eight times more seneltlve thin ear ether known phone. Not Mtlefled with eren such a meritorious article aa thta, the manufacturer, hare now produced the ICaeter Baldwin Phone. A 40% improvement in refinement and workmanship. • Going still further, the* hare designed the Claropbone, the moat marvellous speaker yet produced. Prices: Singles, $9.00 Headset, $16.00 Clarophone Loud Speaker, $22.50 TUB MOST SENSATIONAL radio development slnoe the Vacuum Tube. After years of experiment and proof, thla genuine foxed Be die detector la now available to amsteur and professional operators. Its introduction marke the third GREAT step In the progress of Radio— first the crystal then the vacuum tube and now the wonderful Price, 13.50. sent postvald. Direct or at your dealer t. CLARK & TILSON 1 EAST 42d STREET NEW YORK CITY RADIO PARTS AT CUT PRICES VACUUM TUBES UV200 $4.00 UV201 5.01 VT1 6.25 VT2 7.25 WD11 1*, Volt 6.90 Meyers 3.75 VARIABLE CONDENSERS KOEHLER HIGH GRADE MOULDED ENDS 3-Plate $6.95 11- Plate 1J5 21 -Plate 1.75 43- Plate 2.15 HEAD SETS $6.00 Murdock's $4J5 8.00 Brandos' 6.90 22.00 Brown'* 14.00 6.50 Turney's 2.95 $10.00 Stromberg-Carbon $5.75 16.00 Baldwin Master 12.75 9.00 Baldwin Single 7.75 8.00 Federal's WESTERN ELECTRIC HEAD SETS, THE SUPERSENSITIVE PHONE USED BY THE SIGNAL CORPS AND NAVY. BOUGHT FROM THE U. S. GOVERNMENT. TYPE 194W (THE BEST MADE) $8J6 Mail money orders— no checks LIBERTY RADIO COMPANY 106 LIBERTY STREET, N. Y. CITY Reference: Bradstreef s and Bank of The Manhattan Co., Re Diniti7firl hv

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28 RADIO WORLD GIVEN FREE Aerial Equipment or Dust-Proof Crystal Detector with $10.00 Purchase 3 o! • © © © ■ IT WILL PAY YOU TO BUY NOW SAVE $40.00 S81.S0 SlSt.50 Special at List price n, -Hove It the popular and widely known C Model BelL Ilk a •»"•«»• l™« RFTKIVER— • eet yon will be proud JItoO-STACIK AMPLIFIER. Or.lT a limited Quantity at thU price. ACCESSORIES TO GO ™* AB?Ij, SET (lew Storage Battery). |1IA and your •ptlon of a Marnavoi or Bead Bet at price lilted below: LOUD SPEAKERS ONATOX . -10TONB, ettihtlj ehoo worn. HEAD SETS PDTAAL S stern Beetrle tat. Imported Bet Itogg l5.Ce • •• •.Of 8.88 Emr la Mr last eaVsrileetaeet far Kdkf PbrM*. VZm Zn The. *»M I hwtnvl ef »».••• VACUUM TUBES B BATTERIES n« Tolt ISM Telti'iirii'Bini.' STORAGE BATTERIES ITelt. Amp.. Bilda. Guaranteed Tolt. «• Amp., Bride. Guaranteed BATTERY CHARGERS J. r Better/ Booster. tS.SS 4.SI •HI 1 .15 114.11 11.10 $11.40 14.00 LOUD SPEAKER HORNS net attach one phone Jaet attach jour bead eat PHONOGRAPH ATTACHMENTS Pita any Phonograph and Phone SPECIAL VARIOMETER Ooaranteed perfect DUO LATERAL COILS DL 15. 35 and 50 DL 75, 100 and J00 DL 150 DL 1150 DL 1500 ts.oo 0.00 $0.75 •2.00 •0.35 .50 .OS 1.35 1.48 DL COIL PLUGS Oenaplete with atrap. TRIPLE COIL MOUNTINGS with Leada SIGNAL CORPS VT. I VACUUM TUBES traaranteed originals •0.50 •2.50 $5.45 John Bull's Radio Exchange WHAT is said to be the first radio- phone exchange in the world was recently opened at Croydon, England, the point from which the air lines to the European Continent take their departure, according to Consul Linnell. The chief use made of this exchange is to connect the serial-traffic controller, who has his headquarters in a control tower at Charing Cross, London, with the pilots of the air express flying be- tween Croydon and the Continent. This wireless exchange can also con- nect the phones of the airships and air- planes while in night with any office at the aerodrome at Croydon, making direct telephone conversation possible. The pilot of each aerial transport is now required to report his position to the traffic controller every fifteen min- utes, so that the progress and position of each plane is known throughout its journey. The controller is of particular value in directing the course of the air- craft in cases of fog, and in giving them special directions for landing. The Radio Bug I WAS sitting one day at my office desk, Writing of boys and men, When a radio bug crawled out of a crack And perched on the tip of my pen. He scratched his neck with a wiry paw And gazed at my half-writ poem. Then settled back with a sleepy air And ohmed an indolent ohm. "Your room is chilly," said he to me, As he shivered his aerial wire; "If I were you I know what I'd do — I'd build me an ampli-fire." Then, tipping back 'till the pen point cracked, He ohmed again and said, "I swallowed a couple of codes to-day Any they gave me a pain in the head. I asked him about his sister Ann, And Galena so crystal fair. "Oh, Gale is tickling the cat," said he, "And Antenna is up in the air. "I think that Ann's getting sour because Of the unripe currents she ate. For when I come with 'the weather* she scolds, 'Now, wi-re you in-su-late?' " He kicked his foot in a drop of ink. Then slid from my pen with a snap — Gave a switch to his tail and disappeared Where the spark had begun to gap. — Le Roy W. Snell in "The American Boy." "If I buy a radio apparatus, is there any danger of getting a shock?" "Only when the dealer tells you the price.'" — James Madison's Comedy Service. tVi West fi'"«h Street. New York City ( olnmbua 8584 Avrnue Avenue L NEW I'/t VOLT DRY CELL TUBE WB-11 $8-00 MAGNET WIRE — Write your inquiries. AERIAL WIRE Bare Copper — 100 ft $0.35 f> STRAND PHOSI'HOR BRONZE — 100 ft 50 AIRPLANE NAVY WIRE) — 100 ft 78 STANDARD MAKE DETECTOR AND TWO-STAGE Samples which are out of their boxes, but have not been used, values that were aa high In price as l?5 — a few at $38.08 Add pottage, deliveries made dally. RADIO DISTRIBUTING and AUTO SUPPLY COMPANY NA-ALD DE LUXE V. T. SOCKET acalaat cardloae at teeter*. Ne isle. Beet at awelesd _ PraeUeallj senceaieble. slat. Witt aaterlar ratafee easaaat. Vm « of ho lbs or soldering Iron. All m isusvuea. Mar be 8 Watt power nitty the Highest quality throuehoot Prtee. TSa. Sncrin/ wrt.fKwMfiViii lor ALDEN-NAPIER CO. Deal. L. O Willow St. Stvriafftelej. Me Reliable and Beautiful RADIO-A RE -CHARGER THE RADIO-A is a highly efficient dependable piece of apparatus, absolutely fool- proof, easily attached by sim- ply plugging into ordinary 110 volt lamp socket. In case of current failure, the unit cuts out automatically until current is resumed, without discharg- ing battery. It is designed expressly for re-charging radio filament bat- teries, but may be used for automobile or any other stor- age battery of reasonable size and capacity. Price, $18.50 Dealers and Distributors Here's a Winner! Writs as for full particulars). Simply eerew late any US volt laasre socket and connect the terminate te yearr battery. Impossible) to hook-op RADIO-A charge* either way. .■'fCHARfiP' A compact portable Ite-charglng Vmlt that will folly chance • 100 A. H. Bat- tery overnlfbt, for from Be to lSe, ac- cording to preTalllna; ratee. LAST A LIFETIME King Electric Mfg. Co., Inc. 1681 FII.I.MORE AVENUE Bl'FPALO, N. T. Digitized by Googk

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RADIO WORLD 29 Cavite to Washington, by Radio, in Four Minutes radio set and wears receivers around the house all the time. —New York Globe. THE transmission of a routine radio- message from the Naval Station at Cavite, Philippine Islands to Washington, D. C, was accomplished recently by the Naval Communications Service within four minutes. The total distance is 11,500 miles, establishing a new record for long-distance land and transpacific com- munication. Ordinarily, with the delay on account of schedules, a message from Cavite to the Navy Department would not be de- livered in less than several hours, and sometimes a whole day is required in the transmission, due to relaying and other causes. Of course, the message was relayed at San Francisco, where it was received from Cavite, but as the radio circuit to Washington was "set up" the message was relayed immediately. Within four minutes after the sixteen-word dispatch left Cavite, it was received on the aerials on top of the Navy Building in Washing- ton and, read in the receiving room below. Radio communication is said to be in- stantaneous, and a signal is instan- taneous; but a message is slower due to Hearing Atlanta in Des Moines pDITOR, Radio Wosld: I noticed *-* in Radio World (No. 29, dated October 14) that a Des Moines, Iowa, man heard Atlanta, Georgia. We pick up Atlanta every time they are on — and they come in perfectly. We also pick up the Norton Laboratories, Lockport, New York; also Schenectady, New York, and both come in loud and clear— just as natural as if in the same room. Our outfit is only a single detector-bulb regenerative set, but it works fine I — Newby Auto Electric, Milford, Iowa. Clever Lawyer— Now, if you will let me have some of his love letters — Breach-of -promise Gertie — I haven't any. We both had radio sets. —Topics of the Day" Films. FRS ALL MOLDED UNIVERSAL COMBINATIONS S Unit* Id S F. R. 8. Molded Variometer* $4.00 P. R. 8. Molded Vsrioronplers SS.00 F. R. 8. Molded Bank Winding*. . . S5.00 Bank Windings are IntPrchanxeable for direct mounting on either Variometer or Varlocoupler. Universal — Accurate — Interchangeable Dealers Send for Quotations A Complete Two-Stage Long Range Receiver Set Includes two Federal Transformers. Condenser. two-molded variometers, molded verlocoupler, three V. T. sockets, filament rheostats, dials Read 'Em binding posts, switch points: In Mtnic- tlve cabinet and drilled ptnel: complete, ready to honk up. A 1125 Radio for $40 F. R. S. Radio Corporation Fort 8t. Detroit. Mich. the fact that time is required to transmit it, record it, retransmit and again record. Westward, transpacific radio messages are relayed to Guam and Cavite through Honolulu. Recently through the opera- tion of the Fanning electrical relay at Honolulu, 184 words were automatically relayed to Guam from San Francisco without being transcribed or retrans- mitted, thus saving considerable time in their dispatch. Radio Jokes Jay — How is your new Radio set? Ray — Great, but my wife is kind of jealous of it I Jay — Howzzat ? Ray — I have a loud speaker. —"Topics of the Day" Films. "The Radiophone has wonderful possi- bilities." "Yeah. When they get it perfected we can visit with relatives without hav- ing to feed 'em." Spinkus — Old Henpeck doesn't look as downhearted as he used to. Spunkus — No, he doesn't have to listen to his wife talk any more. He has a INSU-LITE 1/8" —..1 par In. A .»1S per aq. la. N E L S 1/4" —M par aq. lav DEALERS : WHU for dtocesmsa. General Merchandise Co. 141 Market Street. Newark, If. J. NA-ALD SMALL SPACE V. T. SOCKET I f*> li.ag. ALDEN-NAFIER CO. DIALS r— 20c 23/4-_ 2Sc 3"— 27c with brass insert and set screw. Specify 3/ 16th or V4" insert. $1.75 Sesco Variocoopler, 600 meters. $2.50 Sesco Variometer. One-half with ordtr. Balance C. O. D. Standard Model 8 Phones 2500 ohms, $5.75 Standard Electric Sales Company 843 BROAD STREET NEWARK, N. J. SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Please send me RADIO WORLD for „. 1493 Broadway. New York City, please Had enclosed % lUBSCKIPTION RATES: •Ingle Cope I JS Three atoefas 1.J0 Its Moots. .J 00 )a* Year (SI Isaacs) 4.00 \4d II 0« s Vest lor Poretgs .nrt (seed las Postage* Digitized by e-

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? DEPARTMENT AT fa A WORD TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department U intended for •vsrybody who wants quick action an ■hart announcements covering the buying, selling, exchanging er general aierchsndUing in the radio field. Readers of RADIO WORLD will Bad that it pars to read these columns every week. Advertisers will get a tan day service here— that is, cony received lor this department will appear In RADIO WORLD on the news-stands tan days after copy reaches as. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. per word (minimum of M words, including address), U« discount for 4 consecutive insertions, 15% for U consecutive insertions (I months). Changes will be made in standing classified advs, II copy is received at this office tan days before publication, RADIO WORLD CO, 14» Broadway, N. Y. C. (Phone, Bryant 4714.) FOR QUICK SALE-Westinghouse R C at best offer. Daryl McClung, 1221 9th Avenue, Hun- tington, W. Va. FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO," Write today for complete list of premium! and our special sub- scription offer. "RADIO," Pacific Bldg., San Francisco, Cal. RADIO HOSPITAL. Radio sets repaired by practical radiotrician, and experimentations under customer's supervision. Mail orders filled MELCO RADIO, -.:. 37- A Bedford Street, New York City. RADIO ENTHUSIASTS! For Sale-A Complete Colin B. Kennedy Universal Receiving Set, al- most new and in excellent condition. Remarkable long distance set, giving range of wave lengths from 175 to 25,000 meters. Hsve continually beard European stations. Owner is in a position where be can not use set All communications may be addressed to Frederic W. Proctor, The Ambassa- dor Hotel, Park Ave. and 51st St., New York City. ADAPT your socket for Westinghouse dry cell tubes— no changing of connections needed. The Suneco adapter costs only $1.50. Sent postpaid on receipt of price. Clark & Tilson, 1 E. 42nd St., New York City. UNWIRED REGENERATIVE SETS Details, Cabinet, 2 Condensers, 2 Honeycomb Coils, Coil Mountings, Socket, 1 Tusko Dial Bevel, Formica Panel, Grid Condenser and leak, Bradley Stat. Price $16.00. Frost Phones, $4.25. Also, Phones rewound. LOUIS WERTS, m St. Julian St, Peldn, 111. BRILLIANTONE RADIO PRODUCTS Dept. E, S74 Columbus Ave, New York City $3.50 23-Plate Var. Condensers, .0005 41.75 4.50 43 -Plate Var. Condensers, .001 2.25 ■ 4.50 Thordarson Audio Amp. Trans 3.00 5.00 B. R. P. Audio Freq. Trans. (11 tol).... 4,00 7.00 U. V. 712 and Freq. Trans. (Radio Corp.) 6.00 6.50 U. V. 1714 Radio Freq. Tr. (Radio Corp.). S.50 .70 Jacks single open or closed (Firth) .35 .90 Jacks double closed (Firth) 50 .002 and .005 Mica Bakelite Condensers..' 25 .0005 and .00025 M. B. Cond. with Var. Leak... .25 .0005 and .001 Fixed Mica Bakelite Cond 20 Tub. Grind Leaks, H, 1. 1& 2, 2>4, 3 Megohms .45 Arrow Variometer 2.25 B. R. P. Variometer (to 800 Meters) 3.00 ISO Degree Vario Coupler (wound Green Wire) 1.65 B. R. P. Vario Coupler (Panel & Lab. Type) 3.50 Send Money Order, but do not add postage for mailing. Pkg. will come Parcel Post Collect. A Vacuum Tube Dry-Cell Set Bat has ■ wan'-lenath <t 150 ta I (00 nstsrs. Dsalsrs sad Jabbers Writs ts LINCOLN RADIO CORP. Manufacturer. UC West Cfth Street New York, N. Y. What Is It? THE State Music Dealers' Association, of Iowa, met a few days ago and discussed the radio situation, says "The Mail," New York. Whether a radio set is a musical instrument or a scientific commercial device was one of the "big" questions that occupied the attention of the members. The delegates decided that should they class the radio receiver as a musical instrument the various members would lend support in exploiting radio. This was an odd discussion. That it should occupy the attention of a busi- ness-getting organization is one of those things that cannot be understood. In the first place, whether the radio instru- ent is a musical device or another class of utility, is of no importance. Is the phonograph a musical device? Not essentially, although 95 per cent of the records we have arc of a musical nature. MURDOCK PHONES-type 56, 3000 ohms... $5.50 MURDOCH PHONES— type 56, 2000 ohms... $4.50 U. V. 200 (Detector tube) $4.50 U. V. 201 (Amplifying tube) $S.8S Postpaid in U. S. Send 25c for 208-page radio manual and cata- logue. A. V. Gregory, 42 Broad St, Red Bank, N. J. ISSUES OF RADIO WORLD from April 1 to Oct. 7 (27 numbers) for 15c a copy, or the whole lot for $3.15. Or send us $6.00 tor one year and •tart with the first number. RADIO WORLD, 1493 Broadway, New York. BROADCASTING STATIONS! Letters and ad- dresses of broadcasting station to- date appeared ia Radio World for Oct. 7. Sent on receipt of 15c Also a broadcasting map appeared in Radio World No. S. Sent on receipt of 15c Radio World, 1493 Broadway, N. Y. City, N. Y. II in nil i rs of Company, Ransjvtna r. 5133 We oodworth Street, Pit Rogers R Ittsbnrnh, PATENT*— Electrical oases a specialty. Pre- Lewyer, char gee. B. P. FUhburne, Registered Patent rer, m McGffi Bldg., Washington, D. C PATENTS — Send for form "Evidence of Con- ception'' to be signed end witnessed. Form, fee Schedule, information, free. Lancaster and All- wine, Patent Attorneys, 259 Ouray Bldg., Wash- ington, D. C FRENCH TUBES, genuine (no bootleg with French name), most sensitive and economic. (Good for detectors, amplifiers, and especially for radio frequency. Will work very good on two dry cells.) Price $3.25. ATLANTIC ft PACIFIC RADIO CO., 131 W. 37th St., near Bway., New York. Exchange Jolly mteresting letters through our Crab! Stamp appreciated. Betty Lee, Inc., 4254 Broadway, New York City. Are yon familiar with all the radio symbols need la the various hook-ups published m Radio World? If not, secure, a copy of Radio World No. at, dated Sept 23. In this issue was a com- plete table of all important symbols used la radio cons traction and testing. Send 15 cents for a copy, or $5.00 per year, and have subscript i— start with that issue. RADIO WORLD, 1491 Broadway, New York City, N. Y. RADIO MAN, eleven years' experience in all sides of the game, capable of construe ting, fat- stalling, operating broadcasting station of any power, desires permanent connection. Go any- where. What can you offer? Evans, Mamas Pier 48, N. R., N. Y. C NEWS AND GOSSIP OF THE STAGE Bead 10c for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.0* rear, $2.00 six months, $1.00 three months. New York Star Co., 1493 Broadway. N. Y. ASTONISHING results Rokay Regenerative Hook-up without use of Variometers — variocoup- lers, switches, taps, etc. ONE SINGLE CON- DENSER CONTROL ONLY. The coming re- ceiver. Simpler than a non- regenerative— better than any regenerative we have tested. Hook-up, $1.00. Money Orders only. Saves you $10.00 in building your own. With properly wound coils. $3.50 post paid. Complete receiver parts on wood base with Vacuum Tube, $8.00. Head set and "B" Battery, $21.35, Exprees paid. Rokay Elec- tric Co., Ingomar, Ohio. HELP WANTED— MALE EARN till to $2St Monthly, expenses paid, as Railwsy Traffic Inspector. Position guaranteed after 3 months' spare time study or money re- funded. Excellent opportunities. Write for Free Booklet G-151. Stand. Business Training Inst.. Buffalo, N. Y. DO YOU USE A CRYSTAL DETECTOR T ARB YOU MAKING A CRYSTAL RECEIVER T In- crease the efficiency of your crystal •■elector UW per cent by using a "FT" Ultra-Sensitive Con- tact Of special gauge and alloy; makes and holds a quick, ultra-sensitive, stable, adjustment. Endorsed by RADIO WORLD. Using galena, yon may pound panel or table without disturbing sen- sitivity in slightest. Proved practical on ship- board by an oldtime Marconi operator. Using a "PT" Contact on galena, Arlington (NAA) was brought in clesr at 3,300 miles (below the Equa- tor); and Arlington came in loud at 2,200 miles (off Dutch Guiana). In both instances, neaiby ships using vacuum tubas were una hie oven to hear NAA. As to stability. Cape May (WCY) was worked over 1,000 miles, — ■ mlli»g right through crystal with 2 KW spark, without affecting detect- or's adjustment. Replace your insensitive unstable spring or catwhisker with a Contact which will hold ita adjustment in addition to giviag loader signals and music Indispensable for ase in your crystal set, regardless of make. A novice can install. "PT" ULTRA SENSITIVE DETECTOR • CONTACT, with instructions, twenty-five cents, coin or M. O. "PT" CRYSTAL CONTACT CO., Box 1641, Boston 8. Massachusetts. CASH FOR OLD GOLD. Platinum, Silver, Diamonds, Liberty Bonds, War, Thrift, Unused Poetsge Stamps, False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash cant, return mail Goods returned in ten days if you're sot satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. Attention ! Fans and Amateurs ! Have yon built your own receiver? Are you experimenting with any par- ticular hook-up? Are yon improving your set? Are you doing any interesting construc- tive work ia radio? Why not shore (A is lmowledgt testis your fhensavnts of breetter /one who read MAD10 WORLD every toeefcr We want pictures of receiving sets with descriptions of how you overcame some iUEculty, or of any additional part or ajait that you have added to obtain better results. These are the thiage that, prob- ably, the other fellow is looking lor. Send in your information; pictures or what- ever you hsve done to improve the art Remember the beginner is looking for them. We intend to print in this . week, pictured information and descrip- tion of value to radio amateurs. If yon have found a newer or better way of doing anything, don't keep the secret bat tell it to your thousands of brother fans. Send in s photograph of your set with or without accompanying diagrams sad measurement State whether yon figure in the picture yourself, or not, sad with- out sny expense whatsoever to you we win make an engraving and publish it Be sure to write your name and address plainly on photograph. Send in your picture at once, or If yon have not made a set or done anything else in making radio materiel, tell the boy next door all about this offer. Address Technical Editor RADIO WORLD. 1493 Broadway, New York City, N. Y. St? a Booster for Rational Digitized by *adi° w"k

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RADIO WORLD RH EOST ATS — SOCKETS POTENTIOMETERS SWITCH LEVERS ROYHELE MFG. COMPANY Mln. t( auallty ereducta 1*9 Mercer StrMt New York City Write for price* — Representatives wanted Variometers $g.95 Variocouplers each REGULAR PRICE $$M These are standard MOULDED in- struments which is all that is necessary to say. Order maw mm these prions wM to withdrawn wy shortly. Yaw ssensy tosk it am* eeMoAed W. A. DICKSON est E. Fort St. RADIO CITIZENS WE SAVE YOU MONEY Send ns a list of your radio nssda for oar prices. If Its Radio, we have it and we sell it for less. JOHN R. KOCH COMPANY CHARLESTON WEST VIRGINIA MS IH. i • tar (I. It aesslss OhomM Dhl TW dial tint ran Owl. Naracrala engraved 01 bevel and knob at shaped that fingers da aal Hda them. TUB edge with ob U aato steeled set straw la natal insert. WU1 oat warp ship, rinlah and anaoal permanent. SS> .39* .7«a l-lee* dial far ibnatat potentiometer " am I9e-iseb atal tad stamps forntoratore! ALDEN - NAPIER COMPANY It WIHa* St.. Dept. l_ SarlagtaM. Maes. Antenella JVo 4n «P»IW promptly without further eharVe. Chas. Freshman Co., Inc. K Beekmaa St. Now York City RADIO WORLD tblbphonb. bbtant »tb« FDBUBHSD story wrdnrsdat (Dated SATURDAY or BAHB WREK) from publication omen. 14SI RROADWAY. rTaTW YORK. M. T. BY BBNiTBBBY RADIO PUBLiCATIOWS CORPORATION ROLAND BCRKR HRNNBBBT. ML B. BBNMBSS' ■mam a, rn.AWir ROLAND BURKS HBNNB88Y. Bdttsr. ' 14»l Broadway. New Tack TBMD 8. nt.Atar Mauser. 14(1 Broadway. New Tark ASSOCIATE EDITORS: tad. Chas. Bhlart SUBSCRIPTION KATES l i asnta s eepy. $6.0» a rear. It.** sis snaths. 11.5*1* tkraa aattk Add 11.0* a jaar asm tar postage to Canada sad foreign eesntrlee. Boaalpt by saw esbsarlbere af the Stat espy of RADIO WORLD owl lad to then after assigns la la sulieasHe aaksawladgsMBt af their Adrertlslni rataa on raqnast. ADVERTISING BATES: One page: One tuna— f IS*.**. Halt. Quarter. Third and Two-thirds pagaa at proportional rataa. One Inch, one one— **.**. Far agate Has. 10.4*. On four eoneeoutlve Issues. 1*5» discount On thirteen eoneeoutlve iaaoaa. 11% alaaaont. Coier and preferred-poaltlan rataa made knows on application. 10 daya Net. 1% 10 days. CLASSIFIED ADVERTISEMENTS : Fire cents per word. Minimum. It wards. Dis- count of 10* on 4 conearutlTo Iaaoaa— 15% on thirteen aonseeutlTe issues. Caab with order. Rntend aa seeood-elsas matter. Karen II. 1*11. at the Fast Office at New York, New York, leader the aat ef kUrah I. 1879. IMPORTANT NOTICE: WhUo every possible care Is takes Is stats oorreotly Batten of fast and eplnleo In every line printed la sane ever with a ■■melees regard for the fasts, the publisher duautuaa aay reapanalbUlO (or atatanaata rasarduig auaaoana of Patent*, priority of daises, the proper workUi out ef technical problema. ar ether Batten that may be printed In good faith and on Inferasatlan furnished by thaae supposed te ha trustworthy. This statotaeot Is nude Is goad faith and to stro la Since Railroads Took to Radio PLDERLY Lady: "Can you tell me •*— ' whether this train plays 'Silver Threads Among the Gold?'" Train Caller: "No, ma'am. Take the WJZ local for that number." * * * Beautiful Young Lady: "Can you show me what train to take to hear 'Kiss Me Again,' ' 'Love's Sweet Song,' •I'm Crazy Over You?'" Train Caller (very embarrassed) : "I certainly can. Step this way, please I" * * * Indignant Commercial Traveller : "My train is two hours late again. What- zamatah?" Station Master: "It ran out of violin solos at Pittsburgh." * • * Wild Business Man : "Say, looka here I What's the trouble with the 2.15 ex- press?" Station Master: "Three hours behind time. It had to stop at Gopher Prairie for a new crystal set." * * * Railroads may shortly announce the suspension of certain trains because of unfavorable static conditions. * * * Travel Note: Mr. and Mrs. O. Howe Dumm, accompanied by Mr. and Mrs. . A. Lott Dummer and radio sets, left to- day on the 1220 for an extended railroad trip.— W. I. Phillips, in "The Globe," New York. B Batteries That Last For 5 Years tt — SO* VOLTS Send for interesting otroular Deft. B. Sldbenel Badlo Equipment Mfg. Co. 1*«S Jerome Ave. Now York City SET, I ABSOLUTELY FREE BUSH your name and addroae and we will teU you now you can set this RADIO SET ABSOLUTELY FREE. RADIO BKT cornea te you eom- Plata, with alnsle elide I tuning coil, crystal da- tee Lor and phone condroia- ar. AND DOUBLE HEAD PHONES. No batteries reuulred; no experience. Write T.-day far Free ■ Radle Plan. // .HOME SUPPLY CO. Va\RI0 couplers We also make 6 other stylet That List $2.50 up Jobbers — Dealers — Agents Write for Discounts Jewell Radio Sales Co. 90 West St New York Gty Phone Rector MS Ca^kt - . BO CM at ALWAYS FOREMOST IN THE FIELD Announces the New Duplex Cabinet LOUD SPEAKER USING YOUR OWN HEADSET Tea template laud sneakers In ass age far seek phone — eliminate! the latarfaranee betaowa pbasee af the ueual typo, giving aiueb greater relume. Each tana chamber la tare feet lent but the SPIRAL eeiretruetlen a I lew I a vary eamsaet Instru- ment beeltha abeelutely eliminating metal lit dle- tertion— REALLY GIVES A PERFECTLY NAT- URAL TONE. Beautiful hand rubbed mahogany or dark «J cr- eak finish, breaied threat aad fittings.... ~*°"* Hand rubbed black Snlah all nickeled mtlnge At deakra ar postpaid (C O. D. If preferred) MONEY-BACK GUARANTEE. Far tkeee who ews a Baldwin ar ether LOUD SPEAKER UNIT we make a single type 8PIR0LA with aeaalal stasis. $3^5 LH.Donnell Mfg. Co. Dept B. Bex 70 Ann Arbor Mich. Fifty-two issues for 9S.M. Salv Do- ■aartnsmt, RsuHe) World, 14S3 Broodway, Digitized by VjOO^IC

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RADIO WORLD Most Completer-Interesting — Informative Book Ever Compiled on Radio Textbook 021 Radio Text Book By JAMES R. CAMERON Whose textbooks are used and indorsed by the U. S. Army, Navy, and Department of Public Instruction 350 Pages. Profusely Illustrated. Written so the amateur can understand it. At the same time— TEXTBOOK ON RADIO— is a standard textbook for the technical radio student. Over four thousand mail orders received before this book was off the press. "RADIO'S THREE BEST SELLERS !" HOW TO BUILD YOUR OWN RADIO SET, 25c RADIO DICTIONARY, 50c RADIO FOR BEGINNERS, $1.00 Buy From Your Dealer or Use This Order Blank TECHNICAL BOOK COMPANY, 130 West 42nd Street, Dept. W., New York ORDER BLANK- Please send me by return of post your 350-page, profusely illustrated Textbook on Radio, for which I am enclosing you $ Cloth Bound $2.50 □ Se $3.00 □ HOW TO BUILD YOUR OWN RADIO SET, 25c □ RADIO DICTIONARY, 50c □ RADIO FOR BEGINNERS, $1.00 □ Name . . Address Digitized by

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15c.aCopy.$6.00aYear I L L U S (Trade Mark) A T E D. WE Million-Watt Tube Will Radio Voice Across Atlantic A MILLION-WATT vacuum tube, the moit powerful in the world, has just been developed by J. H. Payne, Jr., at the research laboratories of the General Elec- tric Company, Schenectady, New I York. Although still in a stage of development, it promises to result in a supertube that will handle un- usually large amounts of current. Its type is the Magnetron class. Its weight is sixty pounds, and it can supply energy equivalent to that required to light 40,000 25- watt incandescent lamps, the cur- rent necessary to illuminate 1,500 homes. The tungsten filament, if drawn into a filament of the size used in the home, would supply 175,000 lamps. The output of this tube is, ap- proximately, forty amperes at a pressure of 250,000 volts. Ibis is about 1,000 kilowatts. The tube serves to act as a rectifier in changing alternating current to direct current. It is also adapted, in an inverted sense, to change direct to alternating current of any frequency, or to convert low- frequency alternating current to high-frequency alternating cur- rent. This new tube is fifty times as powerful as the recent tube in- vented by Dr. Irving Langmuir, or five times as powerful as the Alexanderson alternator. (Sec page 3 for "close-up" and detailed story of this remark- able dcznee.) (C. International News Reel) OW TO BUILD A 100-METER CONCERT SET— Page LATEST NEWS ABOUT NATIONAL RADIO WW?*

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RADIO WORLD REAL RADIO VALUES ORDER DIRECT AND SAVE MONEY LOOK OVER THESE HOLIDAY SPECIALS Regular Our Pnco Price Unit Andlon Central Paneli *r nA (Detector) I *JS» $5.UU Unit Andlon Control Panels « A nA (Ampttner) UM 1U.0V Glaaa Inclosed Cryital De- « gft tec ton le«i cryatal LW 1.9 V 21 plat* Universal Condenser, m m A bakelite ertdi. .0005 Mfd.... 4Jt Z.5V 41 plate Universal Condenser, n AA bakelite ends, .001 Mid.... SJt J.0V 1 slate Universal Vernier mm Condenser, .000346 Mid lJe .75 Keystone Variometers, ISO- a aa Sfo nt« M0 4.09 6 V. M-H Amp. Storage Bat- i « AA terlee WJe 1Z.09 Open Circuit Jack m .33 Single CUc«rit Jack .71 .40 Doable drce.it Jack M .48 Double Circuit Jack Film- mm ment Control IM .55 Single Qrce.it Jack Filament c4 Control IJ» .04 Saturn Automatic Grip no Telephone Plug lJe .95 AJas Socket Rheostat... im 1.40 Dictograph Headsets, 3,000 o AA ohms 8Je O.UU Dictograph Loudspeakers.... *xn 20.00 Bestone Filament Rheostat.. \M .60 Bestone Variocoupler, J inch > -r dial. 150-600 meters Me 5.75 Bestone Variocoupler, 3 inch m mm dial. 150- 580 meters 7.M 4.75 Bestone Socket, metal shell, mm bakelite base \M .75 Federal Jr. Receiving sets, i r aa Dictograph Headset S.W 15.00 ETery thing sent F. O. B. Jersey City the same dsy we receive your order. Send Money by Registered Mail, Post Office or Express Money All Goods Guaranteed the Best There Is HOLMES RADIO PRODUCTS ooq ' "?C.EN AVENUE !TY, N. J. Radio Smiles By Arthur G. Shirt HAVE you read it? The book which tells you how to make a receiving set with a range of 3500 meters out of grandfather's top hat and an old phonograph record? * * * Where are the novelty banks made in the shape of a radio receiver with a knob that really turns and a tiny bulb that lights ' up every time you drop in a nickel ? * * * Even in this second winter of the radio craze, there are people who think of laundry starch when the name Arm- strong is mentioned. « * • If every youngster hasn't a home- made radio set constructed by his own hands and at the absurd cost of $3.64, it's no fault of the magazine articles on the subject. * * » Try our "Tinpantone," the new radio diversifies Each and every unrelated sound magnified and distorted to ten times its original volume! Can be heard for blocks! Splendid opportunity for weary 'phone owners to drive away un- desirable visitors! You can't appreciate a good horn until you hear this one! * » * Have you written your radio book yet ? » » ♦ News head: "De Wolf Hopper broad- casts to thousands that he cannot see." That's nothing. The Sears Roebuck Company has a greater broadcasting radius than any radio station in the country, and daily takes money from thousands it will never see! » * » Have you heard of the guy who dwells so morbidly on the cost per minute of operating the set when he has company, that his visitors force him to shut the outfit down and talk about it for a while? * * * Already one-half of the world is plugged in on what the other half is saying. * •* • If people listen-in this winter as they did last, the next generation of flappers is doomed to fiat ears and the safe open- ing wrist twist. * * * It's coming! A book entitled, "What Every Ardent Suitor Should Know About Radio." BOYS AND GIRLS EARN XMAS MONEY Writ* tor SO KU AMERICAN CHRISTMAS 8KAI/8. Bell for 10c a let. wtMn aold. tend ua SS and kotp SI. Noueoakar Bras.. SOI E. tit St, Oast M. Brwaklya. N. Y. Treat your detector mineral with KRYSTAL-KLEER If you wmt to m-drs Heerlj — distinctly — and loud. Try It one* ami you wili neter be without It At rour dealers or send fifty c«nu P. M. O. for a Krncrou* sample bottle the KRYSTAL-KLEER Company ZiTS Third Avenue. New York City PUTS PEP IN THE DETECTOR "BECO" RADIO FREQUENCY SET 175 to SO* Meter! t Radio Frequency I Andlo Frvqarncy end Detector All on i Tubes. Bissell Engineering Company 161-167 W. 61th STREET. NEW YORK Thord- arson Trans- formers 345 I Am ' Wo Pay Pi Perfection Radio Corp. of America. 14* Weat Sd Street New York City THIS WEEK WE HAVE "B" BATTERIES 22-H V-small $0S5 Z2-H V-Urge 135 45 V-medium Z2S Watch Our Special* Next Week in Radio World RADIO DISTRIBUTING «* AUTO SUPPLY CO. M Weat Nth St. New York City B'mjr-7Ul Are. Subway. 0th or Oth Are. "W Save Money on Standard Radio Parts $45.M Magnovox $3755 8.00 Brandes Phones 6J5 5-58 Murdocks Phones, 3m Ohms 4JS 5.M Murdocks Phones, 2m Ohms 4.1S 8.M Federal Phones, 2,220 Ohms 125 16.W Baldwin Phones 14.M l.Ot Rheostat, mounted type Jt AM Variable Condenser, Bakelite ends, 43 plate aluminum ends 2.1* 3M Variable Condenser Bakelite ends, 23 plate aluminum ends lJt 1.56 Variable Condenser, Baketite ends, 3 plate aluminum ends lJt 7.0f Jefferson Transformer, No. 45 Navy Type 4J59 12.M Western Electric Phones, 1002 &5t Theae are only a few of our many apeciale. We gfre 15% Discount on anything in Radio William Connor Co. 790 Broad St Newark, N. J. Subscribe for Radio World. $6.00 a year, So.OO six months, $1.50 three months. Digitized by LjOOgLC

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VOLUME TWO RADIO WORLD [Entered as lecond-clasi matter, March 28, 1922, at the Post Office at New York, N. Y., under the act of March 3, 1879.] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. VoL II, No. 7. Whole No. 33 November 11, 1922 15c per copy, $6.00 a year "Close-up" of the Most Important Radio Development of the Hour (Farther description of the illustration on the front coyer of this issue of Radio World.) WHILE radio may be used for short distances, in place of telegraph lines, its real force lies, rather, in long-distance work, side by side with the cables. However, a most important devel- opment has taken place. It is the completion of a 1000-kilowatt super- tube, the work of J. H. Payne, Jr. Mr. Payne created this tube in the research laboratories of the General Electric Company, Schenectady, New York, employing discoveries made by Dr. Irving Langmuir and Dr. A. W. Hull. It is not intended or adapted for use on lighting circuits. Engineers had found that the major problem of tube development for radio has been solved insofar as the size tubes is concerned. They had demon- strated that almost any size tube could be made for radio work and operated successfully. But there was an undeveloped field for tubes in general engineering, especially where high-frequency generators or high-voltage rectifiers might be re- quired. Attention was directed to the de- velopment of superpower tubes for use in the generation and trans- mission of high voltage, direct cur- rent, and other engineering work. The supertube has an output of 40 amperes at 250,000 volts — about- 1000 kilowatts, or 1,000,000 watts. Dr. Langmuir, in describing the tube, says: "This tube consists essentially of a water-cooled cylindrical anode thirty inches in diameter. In the axis of the anode is a tungsten filament four-tenths of an inch in diameter and twenty-two inches long. This filament is excited by a current of eighteen hundred am- peres at ten thousand cycles, the filament excitation requiring about twenty killowatts. By John Kent Another line of development is, therefore in progress : the produc- tion of tubes of high efficiency as well as tubes of larger output. The progress in this direction is more difficult and is apt to be slower than in the direction which, thus far, seemed more important. These developments will come gradually, for the practical construction of powerful tubes giving thoroughly satisfactory operation requires con- siderable development. It would be boasting, however, to predict the limitation of the ultimate use of the vacuum tubes in the power field. (U. Underwood & Underwood, N. Y.) Close-up of the million-watt vacuum tube, fifty time* more powerful than any now In use, which has been developed in the Research Laboratory of the General Electric Company by J. H. Payne/jr. git^dT"*' %M"mT V

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1 RADIO WORLD How to Build a 100-Meter Concert Receiving Set By Frederick J. Rumford, E. E., R. E. First, all the marking of holes on the panel must be completed. The panel is now ready to mount the switch-assembly rheostat, the jack and the binding post. After this is done, we are ready to make the coil which will consist of a primary and tickler winding. The tube is first given several coats of shellac and left to dry. After drying, the primary winding is started about % of an inch from the end of the tube. There are 18 turns in this winding, with taps at the 9th, 11th and 13th turns. On the 18th, or final turn, there is a J^-inch space. Next, wind the tickler coil, which Tickler Figure 1 Layout of panel with distance of holes to be drilled; also the position of the binding posts, knobs, contact points and rheostat. Sug- gested by Frederick J. Rumford. Drawn by S. Newman. IN the near future many broadcast- ing stations in the United States will transmit on a wave length of 100 meters, more or less, because this range gives a radiophone station a larger band of wave lengths to operate over and will reduce interference from other stations. For instance, KDKA has broadcast concerts which have been received quite often by the writer at his home in Roxbury, Massachusetts. I advise any radio fan who is in- terested to build himself one of these little receivers and have it hooked up so that the throwing of a switch will connect it with the antenna and ground circuits. If your concert-receiver is unable to tune in 400 meters and over use this little set. It gives very good results on 100 meters. Below are listed the necessary parts, and their respective cost, for the mak- ing of this set : 1 panel formica, or bakelite, 6"x 7"xV4" $1.26 1 base 6"x6"x^" • 25 1 vacuum-tube socket 75 1 rheostat 1.25 1 jack 75 1 plug 1.00 1 five-contact switch assembly com- plete 1.00 1 six-contact switch assembly con- plete 1.10 1 vacuum-tube bracket for socket... .25 8 binding posts 80 1 set of screws, wire and accessories .50 pound No. 22 D. C. C, magnet wire 30 1 cardboard, or bakelite, tube. 314" diam., 2" depth 35 Total $9.56 Figure 2— Rear of the panel, indicating how the instruments should be mounted. Suggested by Frederick J. Rumford. Drawn by S. Newman. Figure 4— Wiring and connections of the taps of the primary and tickler coil. These make the set regenerative. Suggested by Frederick J. Rumford. Drawn by S. Newman. has 20 turns of the same size of wire as used on the primary. This is tapped as follows: At the 11th, 13th, 15th, 17th and 20th. After the winding has been completed, the coil should be given two coats of insulating com- pound. After the coils have dried, they should be mounted at the back of the panel by means of two machine screws with nuts, fastened firmly at the back, holding the coil-form firm and rigid. The taps are then connected to their respective posts. The set is now ready to be wired. Careful attention should be paid to the wiring diagrams, figures 3 and 4. Re- garding the two binding posts marked Figure 3 — Schematic diagram of the receiver in which the internal wiring is clearly explained. Close attent'on should be given to each connection. Suggested by Frederick J. Rumford. Drawn by S. Newman. Digitized by VjOO^LC

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RADIO WORLD 5 United States May Be Divided Into Radio Zones WASHINGTON, D. C — The radio public is beginning to demand not only good enter- tainment and high-class transmission, but a greater range of reception. In other words, the listener-in wants to reach farther afield. His horizon is extending. He wants to hear the dis- tant stations outside his city and state. The Department of Commerce radio officials, therefore, are making a survey of each radio district to see if there isn't some way by which this can be arranged. One radio enthusiast says that, while he is appreciative of all his local stations, he sometimes wants "to go visiting by radio" — listen to some of the big stations outside the local field — just as he frequently likes to listen to the conversation of others than his immediate family whenever guests are present. It's the same in radio broadcasting, he says. In an effort to aid in seeking a solu- tion of this new problem the Depart- ment of Commerce has written letters to its nine radio district-inspectors, stating that information reaching the department indicates that, throughout the country, a sentiment for silent local radio broadcasting periods is develop- ing so that the listeners-in can hear the distant stations, which is often impossible when local stations are broadcasting. In some sections of the country steps for such an arrangement have already been taken. On the Pacific Coast, for example, what is known as the Pacific plan of time division has been amended so that, from 8 to 10 o'clock each evening, amateurs are silent, thus permitting the broadcasters to have a clear field. (Continued from preceding page) "Output," which really connect with the points of the jack: The reason for one of these sets should desire to hook- up an amplifier with this unit, it can be easily made by connecting jumper wires from these posts to the posts provided from them on the amplifier unit. The variable condensers used in this set are of a small value in capacity, and the grid condenser is, also, of a very small capacity. The grid leak is one-half megohm. The vacuum tube used is a radiotron U-V 200. The B battery is of 22 volts and the storage battery, 6 volts, 60 am- pere hour. By Carl H. Butman At 10 o'clock the amateurs have a period, during which they may com- municate without interruption. In other sections the local broadcasters remain silent for one evening a week, or for a few hours one or two evenings a week, so that those having sets capable of long-distance reception may pick up some of the powerful broad- casters outside their district. The department points out that there is a great fascination in listening to distant stations, and it is the opinion of the Radio Section that this wfsh of the radio public will meet with the co- operation of most of the broadcasting stations when it is understood. Broad- casters and local enthusiasts should advise local inspectors as to what they think of the plan or take it up with the department directly. It may be found desirable to divide the United States into zones somewhat as it is divided into time zones, the stations in a particular zone having silent nights or periods of two hours each. It might be arranged so that the broadcasters in the Eastern Time Zone would not transmit on Monday night ; those in the Central Zone keep- ing quiet on Tuesday; Mountain Sec- tion, Wednesday, and the Pacific Coast on Thursday ; all sending on the other nights. The department inspectors have been requested to bring this suggestion to the attention of owners of broadcasting stations in their dis- tricts and explain it to broadcasting and listening-in organizations. Reports from inspectors will indicate the desire on the part of the public and the atti- tude of the broadcasters, who must arrange the matter, as the department's plan is only a suggestion. Radio fans who complain of inter- ference must not forget, officials point out, that the execution of such a plan will not enable them to get long-dis- tance stations unless they have good sets and know how to tune in properly. The scheme is expected to receive the endorsement of the public and broad- casters alike, but it can only be success- fully carried out with the close co- operation of every one. The reports of inspectors are awaited in Washing- ton with interest. This Is Radio Station 8 BVZ Send Radio World a Photograph of Yours Here .. . «rt we would all like to own-look it over, amateur^ with . view to cop, in. It. e.poci«dly neat and compact arrangement. The batteries are in a locker under the table and hidden from right. The call letter, of thi. .tation m I BVZ. It. owner i, Nicholai H. HiUer, Jr. Carbondale, Pennaylvanla. Mr. Hfller has a few other complete outfit. .prMu? out over the valley, but thi. i. hi. outfit d. luxe. If your, am match It, .end a photoarlph to RADIO WORLD for -- j «u ...n ii.ii ,if ma a pnorogral publication. Digitized by VjOOQLC

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6 RADIO WORLD Wide Field for Experimenting With Aerials Construction of Antenna Involves Many Details Which, if Properly Attended to, Will Increase Efficiency of Receiving Set By Donald Van Wyck FOR the radioist interested in experimenting, there is an in- teresting field that may be easily tapped— experimenting with aerials of various types. Although Radio World has made clear the working of aerials, I will endeavor to cover another phase of the sub- ject Radio enthusiasts who live in apartment houses, in many cases, find it inconvenient to stretch an outdoor aerial. Where circum- stances prevent this, there are only a few schemes whereby broadcast programs may be picked up. A loop antenna, an indoor aerial, or an aerial plug which fits into the electric-light socket, and permits the use of the lighting socket as a means of absorbing the radio im- pulses, may be substituted for the outdoor wires; but in no case will the signal strength be as loud as with an outdoor antenna. One thing that the amateur must re- member: crystal detectors will not function satisfactorily with the in- door loop, as they are not amplify- ing detectors — but sensitive mineral detectors which will pick up and rectify if the outdoor antenna is used. They will function all right, but the range of the broadcasting station must be five or ten miles. For distance with the indoor loop aerial, vacuum tubes must be used with two stages of amplification, for good results. A convenient way of installing a simple indoor antenna is to extend a length of No. 20 single cotton- covered copper wire around the room or down the hallway. If it is run along the moulding, any effect which may detract from the appear- ance of the room may be prevented. We must look for the ground. This can be had by connecting the ground connection from the receiving set to the cold-water pipes or to the radiator. This wire can be run along the baseboard, or a crack in the floor, making the wire un- noticeable. When making the con- nections to the cold-water pipes, or radiator, make sure to file, or clean, the spots where you intend to make the connection. This will give you a good electrical connection when finished. Loop Renal To Set Loop aerial used in conjunction with radio- frequency or superregenerative receiving- seta. Good rendu have been accomplished with each an aerial. It has well-marked iflrectionel prop- erties. It also has the advantage of eliminating interference. The loop aerial is used exclusively throughout the United States Naval Radio Com- pass stations for locating position* of ships. The loop antenna requires a sen- sitive set of instruments such as a radio-frequency or a super-regen- erative set for its successful opera- tion; as the loop aerial is a poor absorber of radio energy, due to the fact that closed circuits have a ten- dency to hold energy instead of ' absorbing or radiating the signal. The loop aerial gives the greatest volume of signals when pointed toward the source of the incoming wave, and thus has a directional effect. Of course, the small-sized loop is what makes the signals weak'; but there is a great chance to try some experimenting with one. There are various ways of con- necting the aerial, or loop, to the set, depending on the type of set used. However, the general method is to connect one end of the loop to the antenna terminal of the set and the other to the binding post of the set marked "Ground." When the loop aerial is employed, no actual ground connection is necessary. The construction of a loop are made up in the form of an X about 4 or 5 feet in height. Across the ends of these pieces, smaller pieces are screwed. These pieces need not be over 6 inches long and should be notched to take the wires and hold them in place. The num- ber of wires needed must be deter- mined by experiment; but, as a starter, try about 8 or 10 turns. For the wire, almost anything will do. No. 18 ordinary bell wire will do. If the builder wishes, he may use No. 22 or No. 24 cotton-covered wire. The fact that the wire is in- sulated will not make the slightest difference. Simply start the wire wherever convenient and wind the form full, keeping the wires spaced evenly. The completed loop may be mounted in such a way that it re- volves easily, so that the radio operator may get the loudest signals and, at the same time, cut out a large amount of interference. Another method of eliminating the outdoor antenna is the use of the condenser plug which enables the radio fan to use the house- lighting wires as the antenna with- out the trouble of installation. In some apartments, .the plugs work very well; but success depends upon local conditions, particularly th manner in which the wires are strung. If the wires are shielded by metal ceilings or conduits, sig- nals will not be as loud as if the wiring is open. If the building is surrounded by steel structures, the results will not be so pleasing. Experiments seem to indicate that the plugs work best on the second and third floors, especially in frame or brick buildings. A regenerative set with two stages of amplification works well with the plug and will pick up broadcasting easily. The antenna plug is a condenser, or a number of condensers, encased, which serve to prevent the live-wire line from surging through the set. The function of the plug is to afford a coupling similar to a condenser in a circuit, allowing the high- i nc Luii^iL uLLiun a loop is — — / — — « m « shown clearly in the accompanying frequency radio currents picked up sketch. The simplicity is at once by the house wiring to flow through apparent. Two light pieces of wood the receiver. Digitized by Google

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RADIO WORLD 7 National Radio Week Executive Committee Ready for Action Subsidiary Working Committees Will Be Appointed This Week MAJOR J. Andrew White, chairman of the Executive Committee in charge of preparations for National Radio Week, to be observed from Decem- ber 23 to 30 (inclusive) has appoint- ed the following to complete the per- sonnel of five members suggested at the meeting reported in Radio World, No. 32, dated November 4: H. Gernsback, Kendall Banning, Lawrence A. Nixon, Arthur H. Hal- loran, and Roland Burke Hennessey. Arthur H. Lynch is treasurer. This committee, • with Major White as chairman, held a very im- portant meeting on November 3 at Major White's offices, 326 Broad- way, New York City, full details of which will be published next week. Committees to take charge of the music and broadcasting programs, the publicity, the special meetings of dealers and manufacturers will be formed. Enthusiasm prevails everywhere and National Radio Week promises to be the one big event of the year. Radio World has received many messages of praise, not only for suggesting the idea, but for passing it on to the radio field at large in order that all may take an equal interest. Among the newspaper comment is the following from "The Globe,'- New York. It shows the spirit of one of the big, progressive news- papers of the Metropolis : A brilliant idea has been conceived by R- B. Hennessy, editor of the Radio World, a weekly radio publication. Mr. Hennessy makes the suggestion that a National Radio Week be held from December 23 to 30, inclusive, during which time short talks appertaining to !he '"son are to be personally delivered »y nigh government officials and broad- Tu,e^j *rom a" broadcasting stations, ine idea is an excellent one both from tne viewpoint of the country itself and troni that of the radio industry. It is Mr. Hennessy's intention to weld »e country together for one whole week ""rough the agency of radio. Political "Us, speeches on art and literature, en- tertainment in lighter vein for those who "".not for the heavier subjects, and reugious and scientific addresses by Tifrsjm their re*Pective fields. i he dates selected come at the season oi uinstmas, an opportune time for a venture of this nature. The wholesome "vantages of life in this country and MAJOR J. ANDREW WHITE Chairman ot the Executive Committee of National Radio Week. particularly at this time could not be brought to the attention of the nation in a better way than through the chain of broadcasting radio stations now available. Of course, there is another thought Radio Development in Cuba Amateurs Enthusiastic Over Establish- ment of New High-Power Broad- casting Station in Havana r\ WING to the lack of adequate broad- casting facilities, radio development in Cuba has not kept pace with the progress of radio transmission in the United States, says Assistant Trade Commissioner Livengood, Havana, in a report to the Department of Commerce but recently a high-power send- ing center has been established in the capital and the market for small receiving sets is expected to widen rapidly. This station has not yet made arrangements to supply broad- casting service, but it will do so soon. The apparatus of the company operating this sta- tion, which has a capacity of 500 watts, is an exact duplicate of that used by the New X0™,. Telephone and Telegraph Company in its Walker Street station. Test messages from the new Havana station have been heard as far away as Princeton, New Jersey. As in all tropical countries, Cuban enthu- behind the movement. That thought is- based on the desire of dealers for a radio Christmas. The contention is made, and rightly, too, that with the decrease in cost of good radio equipment no gift carries with it such lasting benefit and general good-will as a radio set. By calling to the attention of the public the vast amount of information and enter- tainment that can be drawn from the air at any hour of the day, a National Radio Week would not only revive trade in radio equipment, but would most cer- tainly add to the enjoyment of millions of Americans. No less important is the follow- ing letter of commendation from William M. Calder, United States Senator from New York. Senator Calder writes : United States Senate, Washington, D. C Editor RADIO WORLD:— I have had the pleasure on several occasions during the present campaign of speaking over the radio, and I fully appreciate its practical value in very many directions. The whole world is com- ing to appreciate Its unlimited possibilities. I heartily endorse your plan for the celebration of a National Radio Week, and shall be glad to do anything possible to make that celebration • Very truly yours, WILLIAM M. CALDER. National Radio Week is to be an important event. The executive committee is seeking suggestions to make it a huge success. All radio fans and amateurs are invited to co- operate. siasts have met with difficulty because of static" disturbances. In spite of all obsta- cles, however, a considerable number of Cuban amateurs have been experimenting in receiving and transmission. In order to re- ceive from United States stations, apparatus \ir l more expensive kind is necessary, with such sets, messages have been received from Memphis, Detroit, Pittsburgh, Jack- sonville, Wichita, Kansas City, and Schenec- tady. Messages from Atlanta have been most successfully received in Havana. Havana dealers are well equipped to sup- ply radio apparatus in anticipation of broad- casting from the new Havana station. Inter- est in radio matters is thoroughly active, and when United States facilities are available, merchants believe that Cuba will offer a promising market. Be a Booster for National Radio \J^b?^7 anxJou* inquirer*: RADIO WORLD has no free- list. One copy is ••»* "f .» voucher to each advertiser or advertising agent represented in current issues. All other copies are paid for on subscription or through the new* trade. Digitized by

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8 RADIO WORLD Single-Tube Superregenerative Receiver By C. White, Associate A. I. E. E. THE interest taken by amateurs in the development of the super- regenerative circuit indicates that there is a preference for the more scientific receiver, although its actual construction does entail many difficul- ties in wiring. Up to the present time, many designs of this famous circuit have employed either two or three tubes, but the objection to such sets has mainly arisen from the necessary com- plexities of the general connections. Some radio fans tried to build a multi- tube superregenerator, but failed be- cause they attempted to crowd the ap- paratus into too small a space. This is a common fault with most amateur construction, and the poor results are commonly indicated by all sorts of howling, audio-oscillations, and ex- tremely sensitive tuning-adjustment without the desired amount of selec- tivity. Frequently, such troubles are caused by improper shielding or a lack of shielding of the component parts or groups of parts ; or, perhaps, poor con- densers and loose connections. * So, no matter what type of modern circuit the novice is considering, it is paramount that he pay very careful attention to minor details of construction, which often determine the actual efficiency of the outfit. The demand for a circuit employing the superregenerative principle with a single tube has been apparent from the start. This demand has been due to two chief facts; first, the two- and three-tube outfits have been very bulky and by no means easy to carry around, especially since a storage battery of very large capacity is needed to supply the filament currents. Second, al- though the results obtained have been truly remarkable, the cost, both initial and maintenance, has been far in ex- cess of that which the average amateur is so disposed to pay. Hence many JVooc/ s Tmtttviic Figure 2— Schematic design of a plat* potential battery for a single-tube superregenerative receiver. Drawn by C. White. have been at work trying to perfect a single-tube outfit that possesses most of the points of advantage of the larger types and still retains the out- ward and inward simplicity in design, and, also, is immune from excessive costs. Since it is rather hard to defi- nitely connect scientific perfection and financial economy, we frequently must compromise between the two and make some slight sacrifices in favor of one or the other. The single-tube super- regenerative receiver does not have the flexibility of control and the extremely fine selectivity, although in size and cost it is really in the class with the average regenerative-set employing variometers and a double-tuning cir- cuit. It is quite simple and it is pos- sible to make up a receiver that is very Figure 1 — General wiring connections of the single- ! tube superregenerative set. If the amateur wishes he may change the general tun;ng-circuit by using a vario-coupler with two ro- tors; the stator for the primary of the antennae- ground circuit, one rotor for the regenerative tickler coil. Suggested by C. White. Drawn by S. New- man. B. Battery DL.ISOO good for traveling and demonstrating purposes by employing a WD- 11 tube which requires only a 22^-volt B bat- tery and an ordinary No. 6 type dry- cell to light the filament. Personally, I have seen a lecturer's radio set made on this principle which measured only one foot in each dimension. Except for a loop aerial and a loud speaker this recevier was very complete and ready to work in a moment's notice. In Figure 1 is shown the general wiring connections. A vario-coupler with the stator as primary and the rotor as tickler coil was used. But if the amateur so desires, he may change the general tuning-circuit by using a vario- coupler with two rotors ; the stator for the primary of the antennae-ground circuit, one rotor for the secondary, and the other for the regenerative tickler coil. While a double-circuit ar- rangement adds a certain amount of scientific refinement, I do not think it is advisable to incorporate such an ex- pensive item as a double rotor vario- coupler in a single-tube set, especially since, with a loop aerial, it is quite easy to obtain good selectivity and a minimum of interference. As illustrated, a 43-plate variable condenser is placed across the ter- minals of the stator and thus provides a method of sharp tuning. The regen- erative coils consist of two honeycomb Digitized by Google

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RADIO WORLD 9 Why it Is Necessary to "Tune In" WHAT are you doing when you juggle with the slider on your tuning coil, or twirl the dials on your variable inductance? "Why," you answer, "I'm tuning in." But there you stop. Why it is necessary to "tune in" perhaps never occurred to you. Therefore, an ex- planation couched in language everyone may understand, may not be amiss. To begin with — the aerial. If no other explanation will quite cover the idea, the aerial is erected outside or inside, as the case may be, for the pur- pose of catching messages, music, speeches, and press reports, just as a rain barrel is given its place to catch rain water. Falling rain represents some energy, even if it is not generally utilized, and so does the entertainment which comes down through your aerial to your receiving set. It is of an en- tirely different kind, however, and peculiar to itself. The sort of energy that we hope to capture when we string our antennae is what is known as "wave energy," so called because we can more readily con- ceive of it when it is compared to ocean waves. Every transmitting set in the By Arthur G. Shirt country sends out wave energy ; but to avoid interference of the worst kind, the radioists send out waves of differ- ent lengths. Waves have length — and they are not spoken of as being so many feet long, or so many yards, but so many meters. Thus amateurs send on a wave length of 200 meters and less, broadcasting stations from 285 to 485, and government stations on 800 meters. Whatever type of aerial you may put up, it will possess a neat little wave length all its own. It may be from 75 to over 200 meters, and may be de- termined beforehand by working out a well-known formula. If you had just a detector and a pair of phones attach- ed to the end of your aerial, you would be limited to the reception of only those wave lengths which were the same as the natural wave-length of the aerial. Poor chance of ever getting anything with an arrangement like mat. It is "Radio will make this a bigger, better world"— Hoover. apparent that you must have some means of raising or lowering the wave length of the aerial so that your re- ceiver will respond to a wide range of stations. This is done by means of a tuner. The tuner, as most of us know, is a coil of wire connected to the aerial and the ground, and forming the primary cir- cuit of a receiving hook-up. All tuners — with the exception of block coils, such as honeycomb arid spider — have some means whereby the number of turns of wire which are included in the circuit may be controlled. Either a slider or a dial will accomplish this; and by manipulating these devices you put your set in resonance — to use a word which means exactly the same as tuning — with as many different wave- lengths as the size of your coil will al- low. Hereafter, when you set out to tell anyone who is not familiar with radio why you are tuning in, say : "To place my set in resonance with the set which is sending out the music I want to get." Then they will understand, and, at the same time, give you credit for knowing what you are doing and why. (Continued from preceding page) coils, D-L 1250 and a D-L 1500, mounted so that they can be turned axially with respect to each other, thus varying the mutual coupling in order to definitely control the amplitude of the locally generated oscillations. It is highly recommended that a good make of mica condensers be used with these coils. If it is not possible to obtain .002 microfarads capacity in a single condenser, then such a capacity can be made up of two .001 microfarad con- densers connected in parallel. Although, as I have previously said, it is quite possible to make such an outfit extremely compact and portable by using a dry-cell type of vacuum tube with a low B-battery potential, still if the receiver is not to be moved about often, I would advise that a hard tube with a high-plate voltage be em- ployed instead of the soft tube. With this set, a UV-202 tube with 200 volts, or thereabouts, on the plate will give far better volume and results in gen- eral than a UV-200 or UV-201. Nat- urally the average .amateur will object to this on the ground that it is next to impossible to get a cheap reliable source of high potential that will stand the current drain of a power tube ; but such is far from the actual fact. Small storage-cells for plate potential bat- teries can not only be purchased at an f xtremely reasonable price, but can be made up by the amateur from $10 to $15 for a 150-cell battery (that is about 300 volts). The general method is to obtain as many 1-inch by 7-inch test-tubes as there are cells, then cut from a l/16th- inch lead sheet, strips about j£ inch by 18 inches in length for the plates. For the separators, a small stick of white wood may be placed between the two plates in each cell. Any type of device that will hold the cells rigidly in place, will suffice as a container for the whole battery ; but as illustrated in Figure 2, it can be made up of ordinary wooden beams, bored just deep enough to make a firm resting place for the butt of the tube. This type of wooden base, or container, should be painted with at least two coats of black asphaltum paint in order to allay the eating action of the acid electrolyte. It is cheaper and safer to buy from some battery- service station, the electrolyte (dilute sulphuric acid) already mixed, then to endeavor to dilute concentrated sul- phuric acid, which operation, if not properly done, will result in serious bodily harm to the mixer. The potential of the terminal of the battery is determined by the initial potential of the first charge. Such a battery may first be charged and then recharged by either dividing the same into groups of three cells and connect- ing such groups in parallel with a 6- volt D-C supply; or by dividing into groups of 55 cells, if a 110-volt D-C supply is available ; or 1 10 cells for a 220-volt D-C system. The majority of amateurs will resort to the first method, using the same apparatus that they use to charge the 6-volt A battery. After charging has been accomplished, all the cells may then be connected in series for the regular B battery work. I strongly recommend this type of receiver with a hard tube employing a high-plate potential. Under such con- ditions of operation, it is perfectly pos- sible to receive from local stations using a loud speaker with a single vacuum-tube. For those who want the greatest possible results for the mini- mum amount of money invested, there is, possibly, no better style of vacuum- tube outfit to rival the superregenera- tive receiver employing one bulb. But the amateur who wishes an ultrafine receiver of the supertype, would do well to use a two- or three-tube outfit. The single-tube set is not as good, scientifically, as the multiple-tube re- generator. This is quite evident since we must sacrifice quite a bit of flexi- bility of control when we endeavor to make one tube play a dual role. Again I must say to anyone attempting to build any high-grade receiving appara- tus that shielding must be perfectly accomplished if satisfactory results in sharp tuning are desired. Digitized by Google

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The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks What is a vacuum tube? THE vacuum tube is a glass bulb shaped very much like the bulb of an incandescent lamp and of similar size. It contains three ele- ments : grid, filament, and plate. It is called a vacuum tube because the air within it has been reduced to the low- est possible percentage. In moat of the pi— tnt-day radio receivers, an instrument known as inductance, U nmployed to enable the fan, or novice, to operate hi. receiver on the different wave lengths. 2 la the vario- coupUr with It* primary and secondary wind- lass. 1 to the variometer uaed M much for the regenerative effect for amplification. 4 the honey- comb coil explained on this paae. These tastrn- ments are Important ai they are mostly dealt with by the radioman. What is the plate? The plate may be either a wire mesh, a flat plate of nickel, or, as in some tubes, it may take a cylindrical form completely enclosing the other two elements. * * * What is the grid? The grid is usually made of some fine wire mesh. It is a network of fine wire of tungsten, tantalum, or nickel, or a perforated plate of one of the same metals. One end of the grid is connected to the tuning coil and the other end is left free. * * * What is the filament? The filament usually is made of fine- ly drawn tungsten wire coiled in a spiral similar to the filament in the ordinary house-light. The filament is heated to incandescence by a 6-volt storage battery. The battery must not be over 6 volts. * * * What is a honeycomb coil? In ordf obtain the required amount of wire for long wave-lengths it was found necessary to have large, or long, coils of bulky construction. Although at first thought it would seem preferable to wind the coils in more than one layer, radio engineers know that if this were done the final result would not be what it should be due to what is known as distributed capacity. * * * What is distributed capacity? When the wires form a miniature condenser and these condensers are in their right places, they do not belong in a tuning coil — particularly when they are widely spread. So they are called "distributed capacity." If the capacity were concentrated, the objec- tion would no longer hold ; but this is not so. * * * From what does the coil derive its name? From the peculiar appearance of the finished coil. In winding inductances, none of the wires are ever parallel. They cross each other and always at right angles. Radio Hints Useful Facts for the Beginner Who Wants to Know FILAMENT rheostats are designed with a zero point which acts as a switch between the tube and the storage battery, but it sometimes happens that, in the hurry to close the station for the night, the rheostats are not turned off completely. This per- mits the storage battery in the circuit to discharge all night long through the resistance. To prevent this many fans have installed a separate switch, which, through practice, they accustom them- selves to turn off before the rheostat is turned back to zero. * * * The increase in the use of the dry- cell tube is particularly noticeable. Up to a short time ago it was difficult to obtain these tubes, but the supply is now meeting the demand. For com- pact sets to be carried about in an automobile, or even in a pack on the back, dry-cell vacuum tubes are un- usually well adapted. 1 Is a simple sketch showing the wiring- diagram in connecting up a storage battery to the house current, when 110 volts direct current Is avail- able. What is a variometer? An instrument which serves to vary the inductance and the wave-length value of any circuit in which it may be used. It consists of a set of fixed windings and a set of movable wind- ings, the latter being rotated on twin axes in the usual construction. When both sets of coils carry the current, or flow in the same direction, the va- riometer has the maximum inductance • * * All connections about a radio cir- cuit must be soldered, but soldered correctly. There are some general hints that may be given, but judgment and experience are essential. The soldering copper must be clean and the tip well coated with solder. If the tip of the soldering copper is not bright it should be filed clean. It is then heated, care being taken that the tip is not in the soldering flux or paste, and the copper tip coated with solder. The wires are cleaned where the solder- ing is to be done, using fine sandpaper, then a small amount of soldering flux • or paste is applied at the joint and the wires to be soldered are tinned or coated with solder before the wires are joined. * » * After the wires are tinned they are soldered together, using just enough solder to make the joint solid. The joint should not be jarred while the solder is still soft; to do so weakens the joint and gives the solder a dull appearance. A good soldered joint wiH be smooth and bright. All excess soldering flux or paste should be cleaned off. Gasoline or alcohol will assist in cleaning off the paste. This last point is sometimes overlooked, and the excess flux often causes the copper wires to corrode. value or wave length. When coils are turned around so that the current flow in both sets is in opposite directions, the coils are said to be "bucking" one another. Then the inductance and wave length value are at a minimum. Digitized by Google

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RADIO WORLD 11 De Forest Competitor Will Make "Movies" Talk Device Invented by C. A. Hoxie, of the General Electric Company, Will Also Increase Scope of Broadcasting Entertainments By B. S. Beach AN ingenious apparatus for recording sounds on a photo- graphic film to such an extent that the sound may afterward be re- produced in ordinary telephones or loud-speakers has been developed in the general engineering laboratory of the General Electric Company, and brings immeasurably nearer the day of the practical talking-movie. It also means a boon to radio broad- casting studios. From a central studio —say, in New York City— the world's greatest artists may sing or speak before this machine which produces the film. Copies of this film may then be made and sent to other stations and reproduced with clearness. It is claimed that it makes possible the talking-movie, for on a film of normal width can be the picture of the voice of the actor as well as the photographic record of his action, both voice and action absolutely synchron- ized because they are part of the same film. C. A. Hoxie is credited with the invention of the device. It is called the Pallo-Photo-Phone. The record is made by causing the sound waves to produce vibrations on an exceedingly minute and very delicate mirror. A beam of light reflected by this mirror strikes a photographic film, which is kept in continuous motion. The film, when developed, shows a band of white with delicate markings on the edges, which correspond to the sound which has been reproduced. On account of the exceedingly small size of the mirror and its low inertia it is possible, by this means, to produce a sound record which includes the delicate "overtones" which give very quality to speech and musical sounds. This has not been so successfully accomplished by any other method of recording sound waves. The reproduction of the sound from the film is accomplished by moving the film in front of an exceedingly delicate electrical device, which produces an electromotive force which varies with the amount of light which falls upon it. In the past attempts have been made to produce these results by means of selenium cells ; but a selenium cell, the inventor claims, though it re- sponds to the changes in the amount of light which it receives, does not re- spond with sufficient promptness to produce results. There is a sluggish- ness in the response which seriously interferes with the quality of sound produced. By an ingenious combination of vacuum tubes there has been produced an apparatus which responds to varia- tions in the light falling on it with a speed which is so high that it can only be compared with the speed of light itself, or with the speed of propagation of wireless waves in space. There- fore, when this film is moved con- tinuously in front of such a device the device produces an electric current which corresponds accurately with the original sound wave. This electric current may be used to actuate a tele- phone, or loud-speaker. It was used recently to operate the radio trans- mitting station WGY of the General Elecric Company. The voice of the WGY announcer, "KH." was recorded on a photographic film and sent out by WGY with such accuracy that it was impossible to di.-itniguijli it from his voice as ordinarily directly trans- mitted from the station. WW tkm Urn it aavalapea It of wfcita wtth aalicate anli'im Radiofacts to Remember— Signals Staaala which paint of the detector pjtflubon m, t the rigaeb which have faUed to actaete the aV toctor will M U heart. With aapUcatioa, than U, ilrtnaltj, aa critical aafart Digitized by Google

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12 RADIO WORLD Odd Ways of Identifying Stations By Washington R. Service BROADCASTING stations are coming to be known by the voices of their announcers, their slogans, and the stunts they perform in order to identify their. stations, as well as by the cryptic call letters assigned by the Department of Commerce. There is little romance or euphony in the letters WSB, but listeners-in are very familiar with the big gong which rings "Bong! Bong! Bong!" to announce the Atlanta "Journal." The unmistakable southern accent of the broadcaster announcing the "Voice of the South" is also an indication that WSB is sending. As the radio enthusiasts well know, "there are a number of other stations using identifying phrases and sounds. For example, the "Courier-Journal" and "Times," WHAS, Louisville, Kentucky, plays a few bars of "My Old Kentucky Home." WDAJ, the Atlanta and West Point railroa'd station, at College Park, Georgia, has uniquely established its identity by blowing four blasts of a locomotive whistle. When you hear this in your receivers you may be certain that WDAJ is broadcasting. The Naval Station at Anacostia, D. C, NOF, is known by the deep bass voice of the announcer. It is not only in the Southland that these slogans and phrases have £ecome popular. In the West, for instance, is the Palmer School of Chiropractic, Davenport, Iowa. "This is WOC," the announcer states; "out where the West begins." Another station identi- fies itself with : "Out where the corn grows tall." The voice of the spokes- man at WOH, the Hatfield Electric Company, Indianapolis, might confuse one at first. He has a southern accent similar to that of WSB in Atlanta. The pronunciation of the simple word "and" like "a-yand" would hardly seem to locate a station, but ask any one who has heard "Mister," KDKA. Pittsburgh. They will admit that the drawled "a-yand" is a most positive identification. The voices of the evening story- tellers are well known by the small radioites. Some of the broadcasters sound a signal on the telegraph key, giving their call or some single letter indicative of their station besides the customary announcing of the letters. Methods of announcing the time also serve to establish who is at the trans- mitter. Those who hear the Louis- .ville "Courier- Journal" say they like the method of telling the time, as the hour approaches, with a simple state- ment, "Ten o'clock," when the minute hand reaches twelve,' hetter than the standard tick-system of the Naval broadcasting stations. When the Detroit "News" signs off the exact time is given. This is a benefit to those who have not set tfieir timepieces for the night. Probably the custom will grow rapidly, and familiarity with the voices of broad- casters all over the country, as well as the mottoes and slogans of stations, will extend the acquaintance of listeners-in with the voices of the air. Utilizing Ford Spark-Coils for Audio -Frequency Transformers By Ortherus Gordon OWE. SECTION op mono cou_ Illustrations to guide the amateur in making transformers of Ford spark-coils. WHEN the time comes to sup- plement your detector bulb with amplifiers, you will need in addition to the bulbs, sockets, fila- ment rheostats, and two audio-fre- quency transformers. Any amateur who wishes to avoid paying the price of these transformers may make them himself provided he can get hold of two old Ford spark-coils. Most cities have automobile wrecking companies. Such concerns always have some of these coils on hand at a very low price. With a little care and discretion, the amateur can pull the coil apart so that he has the primary, the secondary, and the make-and-break device in separate pieces. This done, throw the vibrator into your spare-parts looker and pro- ceed to construct the transformer with what is left. Leave the primary and the core just as they are, but remove one section of the secondary. Ford-coil secondaries are made in two sections. Place the remaining section in the cen- ter of the primary, bring the thin wires out free and block the ends with wooden partitions. Then you will have something similar to the design shown in the accompanying illustration. Put two binding posts on one end and fasten the primary leads to them. The secondary leads may be taken and made fast to binding posts on the other end. A brass piece bent in staple shape, as shown, will serve to hold together the wooden ends and, at the same time, provide a means of screwing the fin- ished transformer down to the table or baseboard. The whole makes a satis- factory audio-frequency transformer. The Rheostat's Work IN radio a rheostat connects the storage A-battery with the fila- ments of the vacuum tube. The rheo- stat is the valve which permits the operator to increase the electric cur- rent going from the storage A-battery to the filament. Rheostats are heat regulators. Heat drives off the elec- trons from the filament to the plate. When the tube shows a dull red glow the temperature is about 1800 degrees, and electrons are then beginning to be cast off. When the filament is white hot the temperature is 2050 degrees. As each degree of heat is increased from about 1800 degrees a tremendous increased proportion of electrons is cast off. Digitized by Google

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RADIO WORLD 1J Elaborate Radio Equipment of the New Italian Liner "Julius Caesar" (Both photograph! C. Kadcl A Herbert) THE "Julias Cmif," the nwMt at fast ocean liners flymg the Mas of Italy, ha* ana of the meat modern radio oeta on any passenger ship. Her transmitting and receiving equipment makes it possible for her to keep fat communication with either continent when cross- ing the Atlantic The photograph at the top shows the interior of the radio room. The numerals designate the various pi* coo of apparatus aa follows i 1— The receiv- ing goer. X— Charging panel to hasp the batteries charged in accordance with the laws of radio. J— The main switchboard with Its layout of meters. 4— The starting ban by which the main motor-generator la set ta motion as operate the main transmitting sat. S— The noise proof cabas where the motor-generator is placed. • — The main telegraph-key to operate the transmitter. 7— Continuous- wave (C-W) transmitter. I — The wall; sometimee called the "deck Insulators.'* •—The wave changer which makes it possible to work on various wave-lengths. These cover all the important parts of the station. The illustration at the left shows Garoat, Brat radio operator, sending a radiogram It Is of utmost importance to employ all this equip- ment. Whan it becomes necessary to work long-distance (DX work) In order to clear the ship's dally traffic of ssassagss, the continuous wave (C-W) transmitter is "cut m" the circuit and ussd. Not only jloes this trans- mitter enable the operator to cover a long range, but, at the asms time — due to the wave being continuous — eliminates much of the mterfsrsnco that is found In un- damped transmitters. Another feature of the C-W transmitter Is this! It functions best when employing the higher wave-lengths. Usually (M meters srs ussd, hen the transmitter Is shifted to r wave-length. Digitized by Google

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14 RADIO WORLD Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengths for the Busy Reader. RADIO was utilised successfully by a ship's surgeon oa the high seas to secure advice for a passenger suffering from heart trouble. Henry W. Kibbe, an official of the Cadillac Motor Company, recently went to Argentine on the Lamport & Holt liner, "Van Dyck," for his health. He was suddenly stricken with rheumatism of the heart. On the return trip he was under the constant attention of two nurses and the ship's surgeon, Dr. A. R. Jenkins, who daily used the ship's radio in consultation with the best heart specialists in the United States in order to safeguard Kibbe's life. The patient was taken to Flower Hospital after the "Van Dyck" docked in New York City. » • * So many requests for assistance in solving radio problems have reached the Central Technical School, Toronto, Canada, that a special night-class has been started for instruction in building, operation and general care of radio receiving sets. There is a complete receiving-set in one of the electrical rooms and considerable research work is being done. Two hundred students have a good all-round knowledge of practical radio and are able to construct parts, in addition to efficiently handling receiving apparatus. « » * Legislation is about to be enacted in Chili, putting radio on a basis similar to its control in the United States, with broad- casting stations maintained by private enterprise. * * • A committee of radio experts in France, which have been conducting research with telegraphy on moving trains on the Paris-Orleans line, reports that its efforts have met with suc- cess. A small portable apparatus was used, and long-distance signals were clearly received while the train was moving at high speed. During their experiments members of the com- mittee set up apparatus at some of the stations on the tour and invited farmers and others to listen-in. * * * The American Radio Relay League operating department will conduct the third series of transatlantic tests with the co- operation of the English, French and Dutch amateurs in December this year. While no definite dates for the final tests have been decided upon, pending suggestions from England, France and Holland, the probable dates are December 12 to 31, inclusive. During the first ten days of the tests American and Canadian amateurs will transmit signals for reception in Eng- land, France and Holland. The best American transmitters, as determined by reception reports from the European amateurs, will be selected to broadcast the result of the recep- tion of signals transmitted by English and French amateurs during the last ten days of the tests, the same as MUU and WII did last year. Transmitting will be from 7 p. m. of one day to 1 a. m., the following day, during the first ten days; "listening-in" will be from 8 p. m. of one day to 2 a. m., the following day, in the second ten-day period. Two Wizards of Electricity Meet (C International News Reel) Thomas A. Edison and Dr. Charles P. Steinmetx, chief consulting; engi- neer of the General Electric Compear. Dr. Steinmetx is showing Mr. Edison a piece of wood which, but a few momenta before, he had gouged lim> ' - tree with his new artificial lightning-making machine. Weather forecasts sent oat by the National Meteorological Office, France, for the benefit of agriculturists, are received on radio sets installed at parish schools or gendarmerie sta- tions, at a cost of 200 francs. Weather warnings are given locally by sounding a bell. * * * A series of New England Radio Nights to take place during the fall and winter months, is the latest announcement in the broadcasting programme of the Amrad station. It is planned to devote specified meetings at periodic intervals to certain organizations who will be responsible for the programme dur- ing the time allotted. * * * Over two hundred Rochester, New York, radio fans have formed the Rochester Radio Telegraph Club, the object being to study the continental Morse code used in the transmission of radio signals. Headquarters have been established at 36 South Avenue. David Ryan, former navy radio instructor, stationed at Pelham Bay, New York, during the World War, will be the instructor. * * * The United States is now divided into eight radio districts with a radio inspector under the Department of Commerce in charge of each district. Radio inspectors have offices in Boston, New York, Baltimore, Savannah, New Orleans, Detroit, Chicago and San Francisco. The Department of Commerce has licensed about 20,300 stations, and of this number 3,575 are ship and commercial land stations, 11 trans-ocean, 560 special land stations such as colleges and experimental stations, 565 broadcasting stations and 15,780 amateur stations. * • * Montclair, New Jersey, has installed in its high school an aerial equal in size to some of the broadcasting stations. The receiving set is in the physics department and many of the pupils are licensed operators. * * » A radio station at Madras, India, will probably be converted into highspeed automatic plant for operation inland and also to Rangoon. * * * _ Orer 18/100 ex-service men and women are receiving instruc- tion in radio in the Knights of Columbus schools, New Haven, Connecticut, in special radio classes organized by the K. of C, and through the Knights' correspondence school. The latest figures compiled show that those taking courses in auto- mechanics under the same auspices approximate 35,000; but the proportionate increase in the popularity of the study gives radio a large increase over figures of 1921. * * * T. R. McElroy, of Boston, who won the receiving contest in Boston recently, broke his own record with a speed of fifty- eight words per minute, with five errors. * » • Portugal haa awakened to radio! Consul General Hollis, Lisbon, reports to the Department of Commerce that by a recent bill the Portuguese government is authorized to con- tract with the Marconi Wireless Telegraph Co., Ltd, for a system of radiotelegraph and radiotelephone stations in Lisbon, the Azores, Madeira, Cape Verde, Angola and Mozambique. The bill provides that this authority must be exercised within three months from the date of approval so that all installations may be complete within four years. The Marconi Company must bind itself to organize a Portuguese radiotelegraph and telephone company, the board of directors of which shall be composed of seven members, five of whom shall be Portuguese citizens. At least two-thirds of the capital of the new com- pany is to be reserved for subscription in Portugal. If this portion of the stock is not subscribed, the unsubscribed por- tion may be taken up by the government or by any other interest. * • * Over 2,000 hours of operating time, conservatively estimated to be worth $150,000, has been saved to navigation interests in the Great Lakes in a single season by radio advice as to weather conditions. * * * All ships sailing from American harbors, and carrying fifty persons or over, are required by law to maintain and operate a radio set capable of covering at least 100 miles. * * * The broadcasting station of Spokane, Washington, has de- cided to suspend operations two nights a week so that owners of sets there may hear concerts from outside points Digitized by Google

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RADIO WORLD IS Radio and the Woman Crystal D. Tector SINCE the last number of Radio World went to its readers, I have been besieged with telephone calls in regard to National Radio Week. It is too early for letters, but I expect that by the time I sit down to indite my next "copy" for this department, I will have heard from a great many of you — and I shall try to answer you all as cheerfully as I know you will write me. In fact, I have taken Friend Husband's advice, and engaged a secretary. She will open and sort my mail, and I shall dictate to her, as speedily as possible, answers to all letters that come to me, so there will be no delay. I will gladly help you to perfect any arrangements you have in mind to make The Week a huge success. * * * We — and when I use that muchly abused pronoun — I mean a partnership with all radioists who have the best interest of National Radio Week at heart; well, we want this very im- portant event to extend as far as possible — even into every town in the United States. It does seem to me that it should be made a week of social functions — radio dances and dinners and parties — and even radio teas. I can imagine nothing more attractive than a beautiful reception room, flowers and greens everywhere, pretty girls as hostesses, and a receiving set hidden somewhere "exhaling" the most wonderful dance music with songs and recitations in between. * * * Teas are very much in vogue, here in the East. In fact, they have become one of the most popular forms of social pastime. The men seem to like them — and although they usually begin about four o'clock in the afternoon they frequently run far jnto the night. Recently a very charming friend of mine, who is noted for her social affairs, invited me to one of her teas. It was very gay, but she seemed to think that something new would have to be created in order to keep up the interest in such affairs. * * * I suggested to her that she give another tea and let me bring my radio set. Well, she knew as much about radio as a kitten, and when I asked her if there was an antenna on the roof, she replied that she didn't know because she "sent all her wash- ing to a laundry!" However, that part of it has been over- come. She lives right in the heart of the most thickly populated section of New York City and pays a rent that would stagger some of us. So, her landlord found no objection when the matter of erecting an aerial on his roof was finally explained to him. She became so anxious that she wanted to give the radio tea within two weeks. The most attractive cards had been prepared and were all ready to be mailed, when I pre- vailed on her to postpone her event until National Radio Week. She demurred — wanted to be first in the field and all that sort of thing; but when I told her how gay and festive and full of wonder that week would be, she gladly capitulated, and put it off. * * • She has asked me to be "hostess of honor." The event will take place on Tuesday afternoon, December 26. The invita- tions have been designed by a clever artist. The design is a pretty girl sitting before a receiving set and over the invisible ether comes a voice, represented by tiny waves, which is ask- ing, "Will you come to my radio tea?" In one corner are the hostess' name and address, and the date. It is all attractive and neat, and very much in keeping with both radio and what the society reporters are pleased to call "A swell affair." Being a generous person, she has told me that I may go to any cost — and she will foot the bill — if I need anything to improve my set. "Get two sets, my dear, if you need them," was her naive remark 1 * * * Friend Husband says that I will wear myself to a frazzle with all I have to do to make her affair a success. He always throws cold water on things I undertake — at first— but he always comes around when I succeed ; and I generally do. And I am going to see that this affair does not slip up in any way. * * * I was mentioning the many telephone calls I have had re- garding National Radio Week. I did not mind answering on* of them — even if one — a man, at that — called one chilly night at one a. m., and— Friend Husband answered the call I He didn't say anything— just looked ! My late 'phone caller wanted to know if I could suggest his name for a position as publicity disseminator. Don't blame the man. He is just a good example of the American spirit. He thought he saw a chance to make some money, and he wanted to be "Johnny on the spot." That man will succeed. Boy Scouts Will Listen to Radio at Any Time photograph of a troop of Boy Scouts listening In whiU a broadcast story is coming over the rthar. It u claimed that no other of entertainment so deeply interests and holds the attention of boys. Digitized by Google

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16 RADIO WORLD (C. Kadel & Herbert) (Above) The 1-kw. (C.-W.) telegraph transmitter shown in this photograph is used in Professor J. N. Morecroft's radio laboratories at Columbia University, New York City. Its output is as powerful as that of the leading broadcasting stations. Charles J. McCarthy is seen replacing one of the big (C. Kadel & Herbert) (Above) A Y. M. C. A. class in high-speed code receiving. To become proficient in this phase of receiving requires considerable study and patience. The photograph shows J. L. Hornung, instructor of the class, giving some of the students under him an hour of hard work. Mr. Hornung is using a vibroplex high-speed key, used only by expert operators for transmitting signals. It is known as a "time-saver" when fast transmitting has to be done. These keys anaMd in all large radio-stations in the United States. It takes the average student abqta^a^a^aAfo learn code, although some have perfected themselves in six months. Latest News-Pt Week ii (C. Central News Photo Service) (Above) The interior of the after cabin of the flying Miami, Florida; Cuba, and the West Indies. The in a small space, but the completeness of it has rer "boat." Note the big loop aerial and the receiving set. withstanding the noise made by the propellers of the is distinctly heard. Digitized by Google

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RADIO WORLD 17 tos of a Radio (Right) When the Wales recently tent a. 1 •age to the Boy Scout, of Great Britain, the event was regarded a. something ol unusual radio importance In his country- The prince has become a radio fan and has induced bis royal father to Install a set in St. James Pal- ace. The photograph shows a of Scouts listening to (Left) Thomas A. Edison, on his visit in twenty-five years to the General Electric Company's plant at Schenectady, the zo- New York, was introduced to the most recently in connection with recaption. Mr. Edison is shown in photograph with the new Langmulr kilowatt vacuum tube which successfully hurled a radio message across the At- lantic, at the left is George F. Morrison, vice-president of the General Electric Company, in charge of the Edison lamp works at Harrison, New Jersey. In the center ia Dr. Irving Langmuir, search engineer, of Company, whi (Right) Alan Edwards, formerly a radio engineer, ia now singing and acting hi. way to fame in "The Gingham Girl," one of New York, .ucceuful musical com- edies. He is the proud possessor of one of the smallest radio set. in the world. It has a two-bulb regenerator honeycomb-coil, a de- tector, a two-stage amplifier, and can be tuned to 2,500 meters. It is built Into a soap box which ia covered with leather— the finished At • in New York, this set won first prize. Between the acts of every performance, Mr. Edward* en- tertain, the other member, of the company with concert mu.ic and other broadcast numbers. By leaving the door of his dress- ing room open, the broadcast program wafts through the "back of the stage" area. Mr. Edwards, a. one may surmise, built his prize set. He has also built sim- ilar sets for Richard E. Enright. Commissioner of Police, New York City; Miss Pearl White, the mov- ing picture star; Miss Nora Bayes, singer of popular songs; and others. He is a young man of many talents and a staunch (C Kadel ft Herbert) , (Above) The first passenger in the world to be transferred to - airplane was Secretary of the Navy Edwin L. Denby. The submarine moned to it. position by a radio message from the airplane. lot of (C Central New. Photo Service) Digitized by

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20 RADIO WORLD R. A. Heising Has New Device to Detect Radio Signals No. LOUB. Patented: October 17, 1ML Pa- ^teeTlCymond A. Heising, East Orange, N. J. IT has been customary, prior to my inven- tion," says Mr. Heising, in his patent papers, "to provide, for heating the cath- ode a direct current source such as a battery or direct current generator. The external circuit connections to the cathode have been generally made to one side of the filament. As a result, all parts of the filament have not been of the same potential with respect to the anode or the grid, the difference between extreme ends being equal to the voltage im- pressed upon the filament. Where a source of direct current is employed, this voltage, or difference of potential, is constant and, □CORE from anode and grid to the cathode are made to some point in the filament circuit which has a potential equal to the average potential of the filament which in general, is that of the middle point of the filament When the connections are made in this way, the average voltage or difference of potential at any instant between different portions of the cathode and the grid, and the anode, due to the heating current, will be zero. • • • Requires One Pair of Electrodes No. XJOiym. V*\*mn&, October 10, 1M2. Petentsei Alphonsus I_ Golden, Alameda, Calif. THIS is an oscillator for the produc- tion of high-frequency oscillating currents for radio. 'The inventor claims that it is simple, compact, and easily JTMg.J ■ * i — /\^, Figure 1 repreeenU an embodiment of tUa inven- tion shown in connection with an electron dis- charge device. Figure 2 is a modification of Fig- ure 1. Figure J shows how this Invention mar be applied simultaneously to a plurality of electron discharge devices. Figure 4 illustrates how a non- inductive resistance may be employed to obtain the desired average potential of the filament with respect to the grid and cathode. therefore, will not produce variations in the operation of the device. It is, however, more convenient, in some cases, to employ an alternating current for heating the fila- ment, this being particularly true when*a large number of such tubes are operated simultaneously, requiring a considerable amount of power for the heating of the filament. Upon the substitution of such an alternating current heating-source for the filament, the variations of potential differ- ence between the grid and filament or the plate and filament, which are thereby intro- duced may seriously affect the efficient oper- ation of the device." The object of Mr. Heising*s invention is to provide an improved circuit connection for electron discharge devices, whereby al- ternating current may be employed for heat- ing the filament. Current for heating the f: m; is obtained directly from an alter- ■r rent generator or from the second- msformer, and the connections rips Three schematic diagrams of receiver of M. do circuit actuated by other circuits not shown. . This invention, it is claimed, will be useful in the construction of radiotele- graphic receivers comprising a self-in- ductor and a capacity forming an oscil- lating circuit in connection with an in- dicator cidcuit. A method consisting of balancing the external electrostatic ac- tions on all of the elements of the receiving apparatus, so that these actions may be distributed symmetrically with a re- spect to the capacity is an important ele- ment. * * * To Improve Radio Signaling No. 1.4S2JS4. Patented! October 17, 1SB, Pa- tentee: William Hockley Mortage. Chelmsford, England. THE object of Mr. Nottage's invention is to provide an improved system where- by signals received by wireless may be trans- mitted over land lines and a wireless trans- mitter may be operated by signals trans- mitted over land lines. A Wheatstone bridge is used, the each of two adjacent arms of which are formed of A Figure 1 Is a diagrammatic view showing the different apparatus employed in the wireless tele- phone system. Figure I la a diagrammatic view showing a wireless system capable of employing either direct or alternating current and adapted to be used either aa a wireless telephone or telegraph. operated and adjusted. It requires only a pair of electrodes to produce the same amount of smooth, uniform high- frequency oscillations heretofore pro- duced by oscillators with several pairs of electrodes. » » • Receiver for Radio- telegraphy No. 1,42*,S7Z. Patented. September It, Wt. Pat- en tec: Henri Jean Joseph Marie de Reg- nauld de BeUesclze, Toulon, France. HENRI JEAN JOSEPH MARIE DE REGINAULD DE BELLES-* CIZE a French inventor, has received letters patent for a circuit receiver— an ordinary receiver mounting, which com- prises a closed circuit conductively con- nected by means of a self induction with the self induction of a second closed cir- cuit, to the terminals of which the de- tector and indicator are connected, lne primary may be with a closed antennae, for example a frame, or an intermediate In the above diagram A, B, C, D !a a bridge, two arms, A and B, including the secondary windings A' and B' of two similar transformers, the wind- ings preferably being of high inductance. R and R' are resistances included in Arms A and B for purposes of balancing. In the other arms C and D are two impedances, such aa condenaers C and D\ one or both being variable; they may conven- iently be air condensers of the kind used ha radio telegraph receivers, one winding of a transformer, such, for in- stance, as those used in land-line telephony for connecting the receiver to the line. To two opposite junctions of the bridge are con- nected the wireless receiver and to the other two junctions are connected the wireless transmitter. The land line is connected to the other winding of the transformer of one arm. Digitized by Google

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RADIO WORLD Testing Out Mr. Miller's Hook-up J^SgL EDITOR, Radio World— In response to your request regarding the results obtained from the single duo-lateral coil set shown in Radio World, No. 30, dated October 21, I take the liberty to send you the following report: I found it necessary to make the follow- ing changes in the hook-up, which, I judge, will be obvious to you, and am giving my diagram to illustrate them. I changed the position of the grid leak, as, in the position shown in your diagram, it acted as a high resistance conductor for Sdu Mr. aaatic diagram, thawing changes mad* hi Miliar'* hook-up by Fradorlc W. Proctor. the B battery current, which, flowing into the grid as it naturally would, paralyzed the circuit. I also placed a tuned circuit in the plate lead to the telephones. I hope that these changes may be of interest to you. The results obtained on an ordinary antenna and ground were good. This is not a modification of the "Col- pitt's" transmitting circuit.— Frederic W. Proctor, The Ambassador, New York City, N. Y. • • * DITOR, Radio World— In Radio World, No. 30, dated October 21, I noticed the hook-up of a simple one-tube radio receiver. Credit for originating this hook-up was given Mr. Miller of Dallas, Texas. While experimenting with this cir- cuit, I have found a number of ways to im- prove it, with the result that I now have a receiver that, though extremely simple. Is remarkably efficient. I thought that possibly you and your readers might like to know of this little set; for I have obtained un- usual results with it. The objection to the circuit, as you pub- lished it, is that it is too critical, necessi- tating an extremely careful adjustment of the, condenser. To overcome this, I tried a vernier condenser. This was better. How- ever, when two stations were coming in at practically the same point, I could not hear very plainly; so I discarded the vernier, and instead of a honeycomb coil I used an in- ductance constructed as follows: 90 turns of 26 D. C. C, wire wound on a 3-inch tube, 5 inches long. These windings occupy about 254 inches of the tube. Leaving a space of about 1 inch on the tube I wound 2 turns more, skipped Vt, inch and wound 3 turns more. These last 5 turns form the stator of a miniature variometer, the rotor of which has 6 turns of wire on a 2J4-inch tube 1 inch long. This variable inductance enables me to make very critical adjustments with little effort, so that I tan now tune in or out any station within my receiving range. I have found that a .0005 variable condenser is best; also that a grid condenser of .0005 mfd. capacity gives louder signals than one of .00025 mfd. capacity. No grid leak is necessary. Now for the best part of this tale. Instead of using an ordinary 6-volt vacuum tube, with its expensive and balky storage battery, I am using a Westinghouse WD-11 "Peanut" tube, and the results are more than satisfactory. Using this receiver, which fits in a cabinet approximately 9 inches square (both B and A batteries go in this cabinet, too), I have heard the following stations: KDKA, Pittsburgh; the "Detroit News," Detroit; KSD, St Louis; WOC, Davenport, Iowa. The cost of this receiver is less than $20.00.— E. C. Taulbee, 2426 Homan avenue. Waco, Texas. » » * EDITOR, Radio World— I have been using the circuit published in Radio World, No. 30, dated October 21, page 19. for about a year. It is a dandy I I heard Los Angeles, California, twice on one tube only. My aerial is 100 feet long and 30 feet high. I am using a variometer in place of the D-L 50-coil and a variable grid-leak with variable grdi-condenser. A plate variom- eter with a 3,000-ohm choke coil in plate circuit increases the signal strength. I am using a 201 tube and a 60-volt B battery. — William F. Kaiser, M.D., 484 East 23rd street, N., Portland, Oregon. nti ADVICB VARI0 COUPLERS Wm mUo mmkm $ other ttyUm That List $2.50 up Jobbers — Dealers — Agents Write for DUcoanta Jewell Radio Saks Co. M West St. New York City SOMETHING NEW! Variable Condenser Bnilt Right Fnrmiihod oithor if ajar or wain « Made in the most popular sizes, with aluminum plates, cast end brackets, with • 1' diameter Bakelite bashing therein. (A perfect insulator high in dielectric strength). Dealers write for discounts. Ask to see onr Rheostat and Vacuum Tube Socket LOMBARD. RADIO MFG. COMPANY •7-71 Minor** Stroot, Darby, Comm. P. O. Avalied For. "TUNING IN" re n thy simple when voue th nrnrn with the new "POST SOLDERING IRON" TO THE BIGHT TUNE IS VERY SIMPLE WHEN YOUR COMNECXMttS ARE soi r>rarT> with the new POST ELECTRIC COMPANY SS EAST 4ZND STREET, Div. SSS NEW YORK GREWOL DETECTOR $2.00 Nothing Like It Nothing as Good Tka Onaat th. fUacteM. a.rlaa.nr elM bj ItMlf tana >t * popular orlm I far to i It yaar < Always Sot •ad Roody Mid ta- na* It aaa wt a«a SSI soar aafe*. Vmr Dollar kat Ina* RANDEL WIRELESS CO. Sola United Btatt DUtrtintort t CENTRAL AVENUE NEWARK, N. J. Digitized by Google

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RADIO WORLD AdTertiimf Rates, Display, $5.00 per inch, $150.00 per pafe Radio Merchandising Classified Quick- Action Advertisiaf , 5 ceau par ward TtUfhoni Bryant 4796 Let "Radio World" Test Your Goods New Firms_ and Corpora- | ANY buyers of radio goods have been "STUNG." At soma time they bought something that was not right or would not work. Inexperienced manufacturers have rushed into the manu- facture of radio goods in the past eight months while the public in its eagerness to buy has been willing to take almost any- thing. Buyers are now twice shy and cautious. They want to KNOW the goods are right before parting with their money. Our seventy thousand radio buyers who read RADIO WORLD each week, have faith in it. They know that RADIO WORLD does no merchandising, has nothing to sell, that its opinions cannot be bought. Therefore, RADIO WORLD'S endorsement means something. Manufacturers, send a sample of your goods to our Technical Editor, Fred Charles Ehlert, 9006 Pleasant Street, Queens, Long Island, N. Y. It will be carefully tested and returned. If your goods satisfy our experts, RADIO WORLD S endorsement will bo published in our merchandise department without charge or obligation of any kind on your part. When the radio purchaser sees a published test in RADIO WORLD' with the seal accompanying this editorial attached, he will know that the product stands for perfection and has the guarantee of RADIO WORLD. 22 Exhibitors Already for American Radio Expo- sition TWENTY-TWO representative man- ufacturers have already contracted for space in the American Radio Expo- sition to be held at Grand Central Palace, New York. City, December 21 to 31 in- clusive. These firms are the following: Western Electric Company, Inc., New York City. Radio Corporation of America, New York City. C. Brandes, Inc., New York City. National Carbon Company, Long Island City, New York. Novo Battery Company, New York City. Sleeper Radio Company, New York City. General Insulate Company, Brooklyn, New York. Sound Wave Corporation, Brooklyn, New York. Pacent Electric Company, New York City. Stromberg - Carlson Manufacturing Company, Rochester, New York. Holtzer-Cabot Company, Boston. National Airphone Corporation, New York City. Clapp-Eastham Company, Cambridge, Massachusetts. Hutchison Radio Company, New York City. Henry Hyman & Company, New York City. DeForest Radio Tel. & Tel. Co., Jersey City, New Jersey. Dubilier Condenser Co., Inc., New York City. In addition to the twenty-two con- tracts mentioned, nineteen more of the principal manufacturers have made res- ervations for space. Heard at the Radio Counter A Conversation Between Customer and Radio Clerk {Fart IV) I AM owiHng information r»»ardin» my aerial and would Ilk* to know if you can bUp out a food fan." "Shoot! Ill tell you any thins regarding aerials if within my power, Mr. Customer ." "Wall, I own my house and have erected an inverted L about seventy-five fast long, direc- tional north by oast, fifteen feat high from the top of a fifteen-foot poU-wbicb is at. the front of the house to another fifteen-foot pole erected on the house in the rear of mine. Now, when I use this aerial, I can only get the broadcasting station from a certain direction and, comatimea, find it hard to tune. Signals are also of a weak nature. The receiver is O. K." "May I ask what your roof is made of?" "The roof Is of tin— on both houses.'* "Weu, IU explain your trouble regarding weak signals. Whan your aerial Is m may say that the earth, or ground, is due to the fact that the tin roof is (rounded. It acts, in this case, as a ground. Try and get your aerlal so it lays in a position over the actual ground. Point your aerial towards the station you wish to hear. Take off the lead-in at the nearest end of this wire. Use about seventy-five feet and try out your sat. I am sure this will aid you in every respect.'' "Thank you for this advice and, by the way, give ma three small electross Insulators.*' "Right 1 Hare they are— and success to the re- modeling of your antenna." "Good-bye." (To be continued) Stable Firms Will Aid Radio A SHORT time ago, one of the leading manufacturers of automotive equip- ment appeared on the radio horizon with a new line of well-designed and exceptionally well constructed apparatus. Every part of the equipment exhibited the thought and care tions (The Arms and corporations mentioned m these columns con be reached fry comrnmm eating wtth the attorneys, whose addresses are given whenever possible.) American Lamp-o- Phone Corp., Manhattan, make phonographs, $50,000; H. H. Stevens, M. H. Elvidge, F. Riera. (Attorney, L. J. Feinstein, 47 West 34th St., New York.) Ipco Electrical Sales "Co., Manhattan, electrical contracting, $10,000; H. E. Kreindler, F. Padwe. (Attorney, L. Perkin, 261 Broadway, New York.) Sta-Brite Electric Corp-. Manhattan, $10,000; same as preceding. Associated Radio Manufacturing, New York, $760,000. (U. S. Corporation Co.) Capital Increases The Bakelite Corporation, New York, has in- creased its capital stock from $3,100,000 to $5,100,- 000. Radio Real Estate Corp. of America, Manhattan, $2,000,000; S. B. Howard, G. V. Reilly, H. C Hand. (Attorney, S. Ryan, Albany, N. Y.) Jaworsky Electrical Co., Buffalo, supply buai- • ness, $25,000; L. A. Jaworsky. M. Polcyn, J. Mayer, Jr. (Attorney, A. B. Borkowsit, Buffalo, N. Y.) Change of Name The Philadelphia Radiophone Company has changed its name to Durham * Co., Inc. Coming Events The editors of RADIO WORLD will glassy publish news Items of all contemplated radio shows and expositions. Keep us poeted by mailing full Information. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20. inclusive, 1923, George A. King, director of publicity, 417 South Dearborn Street, Chicago, Hi PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION. Grand Cen- tral Palace, New York City, December 21 to 31. Colwell & Korbell, Fisk Building. New York City, directors of publicity. INTERNATIONAL RADIO SHOW. Madison Square Garden. New York City, November 2D to 25, inclusive. E. C. Buchignani, director of pub- licity. SOUTHEASTERN RADIO EXPOSITION. Audi- torium Armory, Atlanta, Georgia, December 4 to 9, inclusive. Co-operative Radio Sales Assn., 295 Pearhtrer St. SECOND DISTRICT RADIO CONVENTION, Hotel Pennsylvania, New York City, March 1, 2, and 3, 1923. of an established manufacturer of precision mechanisms, says "The Globe," New York. Within the last few days a second manu- facturer whose name is synonymous with old-fashioned conservatism appeared in a small way as a maker of refined radio parts. This firm, like the first, had appreciated the business that awaited them in the radio in- dustry, but unlike a large proportion of man- ufacturers that have sprung up over night, these old time concerns were satisfied to wait until they had perfected a line of goods that they knew were right. Still a third company, long affiliated with things electrical, is reported to be deeply in- terested in the invention of a scientific worker in the east. This invention, if found to do all that its discoverer claims for it, will go far toward relieving the intense patent situa- tion that has been the bogeyman of radio manufacturers and dealers. Digitized by Google

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RADIO WORLD 23 Share Your Radio Knowledge with Your Brother ^7 Fans Through Radio World Every Amateur Likes to Know What the Other Fellow Is Doing design of Mr. Love- grcn's circuit which he offers to readers of Radio World and which has given him satisfac- tory results. IN response to Radio World's request for any interesting constructive work in radio that might have been perfected by its readers, Mr. F. W. Lovegren, Box 649, Virginia, Minnesota, sends the ac- companying circuit which he_ has been using for some weeks and which, he de- clares, is hard to equal. "This hook-up," writes Mr. Lovegren, "is not original, but is the Radio Corporation of America circuit with changes." This circuit, he further declares, is very desirable for the following reasons : 1. — It gets all the stations. 2. — It is extremely selective. 3. — It diminishes static considerably. 4. — It does not radiate. "For day time receiving," writes Mr. Lovegren, "I have heard WJAP, WWJ, WLAG, WBAH, WOC, CJCG and sev- eral others loud enough to be audible half a block from the Magna vox. Using no antenna but simply the usual ground connection. I have heard WSB, WHB, WOR, WDAP, KYW, and others too numerous to mention, loud enough, with- out exaggerating, to be audible a block away. I need not mention what it will do using the regular aerial." Description of the circuit is as fol- lows: The antenna inductance consists of 100 turns of No. 20 or No. 22 wound on a 3J4 inch tube, tapped at every 10 turns. The condenser may be either used in shunt, as illustrated, or may be in series with the antenna. No condenser is necessary across primary of the vario- coupler, the tuning being done by the secondary condenser and the coupling. Regeneration in this circuit is accom- plished by an .00025 mfd., variable con- denser which is inserted between the plate of the detector and primary of coupler. This is an excellent means of control- ling regeneration. It will be found that little will be required in this circuit. The detector is not critical in adjustment, therefore no vernier rheostat for the fil- ament or potentiometer, for fine control of plate voltage, are necessary. The potentiometer shown is essential and is used to obtain the proper negative poten- tial on the grids of the radio frequency amplifier tubes. This should have a re- sistance of 400 ohms for fine control although 200 ohms will function quite satisfactorily. The bias battery shown is not absolutely necessary, but maxi- mum amplification will be had only with its use. The proper value will be found by experimenting. From 3 to 6 volts will be required for the TJV-201 amplifier tube. Power tubes require as high as 10 volts. For broadcast reception, a brief sum- mary of tuning this circuit is as follows: For a ISO foot aerial, use 50 or 60 turns on antenna inductance with condenser at about 10 on the dial. Set coupling at maximum; use 50 turns on primary; set secondary condenser between 35 and 45 and the feed-back condenser about mid- way. The rest of the tuning is easy. Send Radio World your hook-up. $2,100 Radio Set Auctioned for $175 (C) Kadel & Herbert Hare Is a photograph of Starling C Sears and a United State* submarine- chaser radio-set, valued at $2,1** which he purchased for $17$. This is one of the finest receiving and sending sets made. Recently, the Navy called for sealed bids on this sat and Mr. Scare's bid of $175 was accepted. On the extreme left may be seen the power-panel for generator-control filament and plate supply. Next to this is the transmitting unit. Note the multiple-switch tuning section for antennae adjustment and the vernier helix. In the same cabinet with the transmitting unit is the receiving unit which covers a wave-length range from 15* to *** meters and, also, two stages of audio-frequency amplification. In the cabinet on the extreme right are three additional stages of amplification. Digitized by Google

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24 RADIO WORLD PHANTOM-CIRCUIT BUILD YOUB OWN. Thle marvel of mjstary. tnllK no aerial, no loop, no ground. Iirlnn In music instead of etatle ehowers. We consistently hear concerte on Munavox, from atatlona 550 mllea dlatant. audible 100 feet from horn. Trie simplicity of thla aet will eurpr. -j you. No radio frequency. Complete lnatruo- Uona with photo of circuit aent prepaid tor 80c. VESCO RADIO SHOP. B.I W-704, Vaaavllla. Omllf. t far II.M aeaulae OaasaMita DM TIM dial that ran tram. Numerala pswpsert aa betel and ana* aa phapod that Onsen da hat Ttua lei ALDEN • NAPIER I* WIHa* St. Dept. U COMPANY SprippfMd. Maja. PRICES SMASHED Bach sale has created new friends and customers with the result that we now announce drastic re- ductions In our quality llnea. All goods prepaid. Send card for complete price Hat. You'll be sur- prised. You'll tell your friends. A sample sav- ing follows: COMPLETE REGENERATIVE VACUUM TUBE SET Our Price Others Psnel — Bakellto — 7»il2" drilled. $1.65 $2.40 Cabinet of 3-ply wood to lit panel. . 1.50 2.50 Two dials — each 35c 70 1.40 Sixteen switch points with nut. Each lc It .48 Four switch stops with nuL Each lc 04 .12 Eight binding posts. Nickel plated 3c. 24 .48 Two switch levers IS 25c SO .90 1 niament rheostat. Highest grade. .85 1. 10 1 varlo coupler. Fourteen tape. . . . 2.25 4.00 1 23 plate variable condenser 1.05 3.50 1 tube socket — Moulded 45 .85 1 grid condenser and leak 10 .25 1 phone condenser 10 .25 1 tube socket support 15 .28 1! feet apagbetu tubing @ 4c 48 .84 15 feet tinned copper connecting wire 30 .45 Blueprint* showing- details to aa- semble 10 .25 $11.32 $20.02 Other artistes taken at random from ear late prise list are- Detector tubes — Cunningham — NOT rebuilt $$.»$ $5.00 Crystal detector of eloaed type 60 1.00 Transformer — Audio frequency 2.05 4.50 Double elide tuner — knocked down. Coll wound 2.50 .... Loose coupler — knocked down. Coils wound 3.75 Loose coupler — assembled 7.50 12.50 Variometer — Hardwood atators 4*4'*- Assembled 2.25 4.00 Frost Fone — 2000 ohms 3.05 S.00 Kellogga — 2400 ohms 8.7S 12.80 Western Electric 2200 ohms 0.25 12.80 Blueprints giving detail of 2 step amplifier 10 .25 Two step amplifier — knocked down Panel drilled 12.05 23.80 Two step amplifier assembled. In cabinet 18.05 35.00 Vacuum tube set In cabinet 7"x 12". Wired 17.95 35.00 Send far list teday ar order direct fram ism. Coeds said subject ts return far rebate ar ax- ahsjige. YOU MUST BE PLEASED. Radio Parts Manufacturing Co. 15 Park Place West Detroit, Mich. Broadcasting Still Grows Fifteen New Stations Bring Total Up to 565 SOME pessimists predicted that broad- casting would begin to drop off in this, the second, year of radio; but to-day there are 565 stations using the 360-meter wave and 15 Class-B stations operating on the new 400-meter wave, assigned to the larger stations giving high-class programs. There is no indication that this means of dis- seminating educations, news, music and many other forms of entertainment will cease; on the other hand, it seems to be growing, and continues to be one of the most popular American pastimes. With broadcasting as general as it is, stations now operating in every state, the popularity of radio, with the listeners-in, at least, is assured, and initiated neophytes join the numberless throng daily. Last week fourteen new stations took up broadcasting on 360-meter in as many states. One — the Atlanta "Constitution" — joins the elite class of B stations on the 400-meter wave. Supplemental List of Limited Commercial or Broadcasting Stations on 389 Meters. WQAP — American Radio Co., Lincoln, Neb., 500 watts. List of Radio Stations Published AN index to commercial and government radio stations of the United. States nas just been issued by the Department of Com- merce, and is available to the public for fifteen cents at the office of the Superin- tendent of Documents at the Government Printing Office, Washington, D. C. It gives complete lists of all commercial and gov- ernment stations, both on land and sea, licensed up to June 30, 1922, including the broadcasting stations. The list of amateur stations is still on press, but will soon be available for distribution by the Superin- tendent of Documents at about 25 cents a copy. College Courses in Radio A HOME course in radio is being given by the extension department of the University of California. The course has been prepared in a style that can be easily understood by the average broadcasting fan. This is not the first home study radio course, however. Last year the University of Wisconsin— one of the _ first educational institutions to popularize radio— prepared an excellent popular treatise on radio which they dis- tributed at nominal cost to residents of the state. SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City. WDAG— Apollo Theatre, Belvidere, I1L, 20 watts. WQAA— Horace A. Beale, Jr., Parkes- burg, Pa., 500 watts. KFBS— Chronicle News & Gas & Elec- tric Supply Co., Trinidad, Colo., 150 watts. KFCH— Electric Service Station, Billings, Mont., 10 watts. WOAD— Friday Battery & Electric Co- Sigourney, Iowa, 50 watts. WNAM — Ideal Apparatus Co., Evans- ville, Ind., 500 watts. WGAK — Macon Electric Co., Macon, Ga. 50 watts WOAC— Maus Radio Co., Lima, O., 100 watts. KYG — Radio Service Bureau, Inc., Port- land, Ore., 100 watts. WNAR — C. C. Rhodes, Butler, Mo., 200 watts. WNAN— Syracuse Radio Telephone Co., Syracuse. N. Y., 250 watts. WOAB — Valley Radio, Grand Forks, N. D. WWAX— Worman Bros., Laredo, Texas, 100 watts. Limited Commercial Class-B Station, 488 Meter*. „ WGM — Atlanta "Constitution," Atlanta, Ga., 500 watts. RADIO PANELS Him dlaleetle reelttaaee; z U" t" z W...., 12" z 24".... Maeufpererers' special si with weed-vert I pa reels. PAGESON COMPANY Assets wanted. Merseants Statlsa. St. Leela. Me. Ml 1J* •elicited. Cats easily (J HIGH GRADE CABINET LOUD SPEAKERS Da sat be deceived by ear law prices. SPIROLAS are set ihpps lastraanats and* ts sell at a law prise. ■H *"! n>tlMr * remarkable derelepmat Bade eeaaibpr (patent pending) in ta market a cabinet li et a mmmi-fmSSS^i MSS .utTs.,^ :L"iv.",Sva.5..f.r thp as n men cabinet tvaa i»t. SZi.TT . . A~V?I trade Is pure, natural teas. *su& •te«v,"S5r srwass t. see anc Mr, fw°y.Br»f„NTK ~ «" In place sf phanss. beautlful^Tk.?^ ^{^JQ dap las the same nnlph'ae" above'.. Ii ' a « 1 »"•"•»• beautiful aahseaay see. finish, bronzed throat. . . SPIROLA DELUXE— New, ference between phones, ^ gg Satin black finish, nickeled ""•nil. otherwise same «2Q or aa DELUXE *O.O0 We alas make the DELUXE and black finish types far use with a slnple laud spppkpr unit, la ordering stats whether tar upp with bead set er salt At Peelers er PPPtsald 0. D. If preferred). (a L.H.D0NNEUMFG.C0.jJ^f«^ .1 as ..urj Please send mt RADIO WORLD for _ months, for which ~ That Armstrong Circuit 8* Pauch iaUraet has beea dlaslared ta ta> STSS* •rUoU- "TBBTBD INTOWON o5 ^^^r «r*^ * *£~*V,iL!?5 •■•»•» tor theee ark* ware Mt sate u aat aaaa Es*r- ^»r«r a*- wni; iwaMM«afc-?S« please find enclosed % SUBSCRIPTION RATES: ■Mn|l*B COp.f •ssaeaeaeoaaee Three Months Us Months MB One Year <J" 'ssnee) MO Add ti de 'or Fcnreigs and Ca- Digitized by Google

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RADIO WORLD 25 —Rocky Mountain Crystals— •CTTU THAN MlUt "Mm. Ca* et let Peatpatd Mmsmfucrurrrs. Jokttrs. Dtttrri, Clmbi. AH*» ft SptcW trait Pric*» l*kf HmbUu 1Mb ft «-*-*», Ik. • ON U BOM »T_ NSW YORK. N. * "WEB" CRYSTALS Bait CTyrl*I Yet. Slnalr Mountlm of Galena, Silicon & Iron Pyrites Raid nkf e nplaeeraeot luerulea; U all dealer* «o by Mil direct on receipt eC PRICE, tSc trlMclboted by WALTER E. BATHGATE ROOM 41. • CHURCH ST.. NEW YORK CITY M*aof**un-er». Jobber*. Duln writ* tar prtee*. Triple Mooted SHAMROCK CRYSTALS Triple —Mag of the three eryeule— Galea*. OlMean end Iran Pyrlta*. . . Held under • replacement fuanatee; at all awl era at ar mall direct en receipt ot PRICE, S*c Distributed br WALTER E. BATHGATE ROOM 41. » CHURCH 8T.. NEW YORK CITY w.-rf^rrare. Jebbere. Dearer! write for prleee. Law Storage Battery voltage, large amperage, iths without Will Attroctivt Dsolrrs' Discounts Writ* for Details WILLIAM LAW COMPANY A bom and Sabtn Street*. Providence, R. I. A Vacuum Tube Dry-Cell Set That ha* a wave-length of 150 to 1000 meters. Dealer, and Jobber* Write to LINCOLN RADIO CORP. : (5th Street New York. N. Y. GENUINE Nathaniel Baldwin Phones $16.00 a Pair Do not confuse these with Muter Baldwin Phones. ELECTRIC SERVICE ENGINEERING CO. 105 W. 47th Street N. Y. City GITHENS TRUTONE RADIO HORN — LOUD SPEAKER First one to eell on ten daw trial Money Guarantee Re4.il Pric. SZ1M Include*. Loud Spoakar Tnrtoae a** bean areaeaaeed the beat ea fee market ay expert*. It baa a elan true tone. aWery radle tee *heuld try Tinlcue aad eempere It with ether*. If TOT dea l aad iTuteoe the beet, your meaty win lefuaded. It 1* eeid en • lea day trial reeaeye*** rematea. II aat earned by year dealer write a*. Distributors and Dsairrt, wntst AUTO PARTS MFG. CO. Subscribe for Radio World, $6.00 a year, $3.00 six months, $1.50 three months. Radio Talks by Naval Officials THROUGH the co-operation of the Naval Communication Service and the American Marine Association radio talks will be broadcasted by representatives of the Navy Department in Washington from November 8 to 11. A large radio receiving-set and loud- sneaker was installed at the Grand Central Palace, New York, by the naval radio ex- perts, and the talks broadcast from Wash- ington are available Wednesday, Thursday, Friday and Saturday. evenings of this week for those attending "The American Marine Association Show. The broadcasting will be done from NAA, Arlington, over the new radiophone set at 2050 meters. The speakers selected include Admiral Coontz, chief of operations; Rear-Admiral Robison, engineering; Rear- Admiral Wash- ington, navigation; Rear-Admiral Moffett, aeronautics; Captain McNamee and Captain Overstreet. It is understood that each of the speakers will talk on subjects under his direction in the Navy Department in con- nection with sea transportation. The United States Naval Band, well known to those who pick up NOF, will play several selections each evening during the latter part of the exposition week. At this, the second American Marine Ex- position, the Department of Commerce has radio exhibits in connection with the work in the Light-House Service, the Bureau of Standards and the Radio Section, an in- spector being detailed to explain the work of the department to those interested. Exhibits are also planned by the Navy and Shipping Board. Radio As You Ride ABOUT the first thing the radio novice learns is that to operate his receiving set he requires a long antenna suspended high in air and a "ground" connection to establish an electrical circuit through the surface of the earth, says Henry Smith Williams, in "The American," New York. The establishment of this antenna system is much the most difficult part of the work of installing a radio receiver. So it is rather hard to get away from the idea that it is an essential part of the radio mechanism. Yet in reality it is quite feasible to do away with this cumbersome apparatus altogether, provided certain other conditions are met. These alternative conditions involve merely the making of a receiving apparatus that is more sensitive than the one with which the novice usually starts. In a word, it is necessary to have an electron tube (triode) amplifier, preferably more than one of them. Wilh one or more such tube* installed before the "detector" tube we obtain what is called radio-frequency amplification. Mes- sages that would otherwise be too faint for recognition are amplified to the stage of audibility, and radio messages of ordinary intensity may be received on a small loop aerial, no cumbersome antenna being re- quired. Almost any coil of wire will serve for such a loop aerial. Five-inch coils' have been used, but ordinarily it is expedient to t'se a loop of about two or three feet in diameter. No "grottnd" connection is re- quired. The apparatus is self-sufficient. Tlic convenience of such an apparatus, which can be installed on a card table in your drawing room or office, with no bother about wires up on the roof or water pipe "ground'' connections, is obvious. Moreover, you may adiust the entire apparatus on your automobile if you wish and "listen in" as you ride anywhere within a hundred miles or so of the broadcasting station. Fifty-two issues for $6.00. Sub. De- partment. Radio World. 140.1 Broadway, V Y C. V A-C-U-U M T U B- E-R-E-P-A- 1 R-l-N-G gSateooliOl SatecoOOOA uDetectsfsl Anptfem* u M T U B E R E P A I R I N G bdlotna CT-lM. UT-Swl. Ceaaareaaam C IH. 0-l»l. IS M. aU (le* weald expeet ta reeeiee tram eew Coorgo H. Parol! Cav, lata. •t*T " " U M T U B E R E P A I R I N •T MMtaWILUL MAOO. V-AC-U-U-M-T-U-B-E-R-E-P-A-I-R-I-N-G LITTLE GIANT RECEIVING SET Including aet of Denble Head Phone* tMO Ohm*. Guaranteed. $8.75 Extra aet of Phone* at time of order $3.50 lalitflci In on all nearby braadkwdnc. Enjoy the nun it, concerta. lecture*, urattver report ■. market rt-ioru. time tleoala. rode, etc — In fact vttty- thing In the air. Enter*.. n yourtelf and frUnda throughout the winter vvenlnu. LITTLE GIANT LABORATORY Box 87 KI THKRFORD, N. J. NA-ALD Fete*. Tee. Spoeisi proportion for den hrr* and yewOera. ALDEN-NAPIER CO. $4 CRYSTAL SET THE LITTLE WONDER" SU« UNMOUNTED Wonder in name aad a wonder fat per. formance. Cannot be equalled lor the price. Catchee distinctly everything broadcasted within 30 mile a. Send for FREE catalog;, deecribtng oar "Little Wonder" aet aad liating radio rap plica. GUARANTEED. TESTED CRYSTALS Calema aad »§*. Radtoclt*.. RaeB-O-Plata Pamela. Al ataae eat ta order Holloway Electric Supply Co, Inc. BS Third A vena* New Yard City Do Yon Like Clear Tone — Sharp and Diatinct? If ao try MARSH'S Vernier Variable Condenser AT LAST Made In Three «t>le*. Trial Km.h and S« rrue ( uniplete. > ully t.uaranleetl i:-ruie ...» •.-,.%*) S:t- Plate e gi Il-I'late <a »I?J Mall ordere promptly filled. F. P. Marsh. 145 Nicoll St. NKW IIAVKN. CONN. Digitized by Google

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RADIO WORLD B Batteries That Last For 5 Years W — 600 VOLTS Bond tor interesting circular Deft. B. Sidbenel Radio Equipment Mfg. Co. 10SS Jerome Ave. New York Ot7 RHEOSTATS— SOCKETS POTENTIOMETERS SWITCH LEVERS ROYHELE MFG. COMPANY Mlra. tf auallty sredoeti MS Mercer Street New York City Write for price* — Representatives wanted NA-ALD SMALL SPACE V. T. SOCKET • far ll.ee. Special proposition tor ttatorm ask* foobert. ALDEN-NAPIER CO. FS To the Man with an Idea I offer a comprehensive, experi- enced, efficient service for kif prompt, legal protection, and the development of his proposition. Send sketch or model and descrip- tion, for advice as to cost, search through prior United States patents, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable me to accurately advise clients as to probable patentability before they go to any expense. Baoklet ef rslnsble Information, and form far properly disclosing row Idea, free an request. Write todar. RICHARD B.OWEN.Pstsst Ur/y. 32 Owen Building, Weihlngton. 0. C. 2276-P Woehrertti Bldg., New Vera City At Your Service! There appeared in RADIO WORLD, dated April 1, IS, and 29, the following articles. April 1 — A 500-MUe Radiophone Employing a 5- Watt Tube, by Frank A. Hahnel. "Tell Me, Please, How Will This Set Receive?" by E. L. Bragdon. Short Cuts in Receiver-Cir- cuit Design, by O. C. Roos. Making a Short- wave Regenerator, by Fred. Chas. Ehlert. April 15 — First Principles of Electricity as Applied to Radio, by John P. Miles. Your Storage Battery, by E. L. Bragdon. What Makes Radio Possible, by Edward Linwood. Ground Connection as Vital as Antenna, by Fred. Chas. Ehlert. April 29— Valuable Pointers on Aerial Con- struction, by Edward Linwood. What Is Meant by Tuning, by E. L. Brag'lon. Radio- Frequency Amplification and Regeneration, by Frank Armstrong. Honey-Comb Coils and Con- densers, by Edward Linwood. Charging the Storage Battery, by E. L. Bragdon. How to Construct the Variocoupler, by Frederick I. Rumford. Each copv sent on receipt of 15c. per copy, or the th -»c» for 45c; or better still, send v ■ '.lion beginning with any one of j anil we will send this PaP'" "I you will then have • 1 lv and constant refer- on 1493 Broadway, New RADIO WORLD TOJtTHO>n. BRYANT 4T»e KTBLISHKD IVRT WTONB8DAT (Dates BATCTRDaY OF HAMI WICK) noM pubucation ornca. 14(1 BROADWAY, NaTW YORK. N. T. BT HRNNBS8T RADIO rUBUCATIOHR CORPORATION ROLAND BURKS HKNNB80T. Presldee! la. B HKNNBS8Y. Ties- Pi eel deal FRRD 8. CLARK. BoeretaiT ROLAND BURKS HSNNSSSY. BtBter. lias Broadway. New Talk ITUCD'B. CLARK. Manafer. lias Broadway, New York ASSOCIATE EDITORS: rrod. Cnaa SUBSCRIPTION RATK§: Fifteen ssBts a espy. le.ot a year. f ».«• far ill sssnths $1.M (or throe months. Add II. 01 a year extra tor postal* I* Canada and foreign oounuiea. Rosotpt by sew sobserlbsrs of the first espy at RADIO WORLD mailed to them aflat ssndlni Is their ardor, la sntssaatle aesnewleaioient at their aubsorlpUan order. AdTortlsInt rates on request. ADVERTISING RATES t One pace: One time— $150.00. Half. Quarter, Third and Two-thirds Paces at proportional rates. Ono Inch, one time— $5.00. Per agate Una, SO. 40. On four consecutive lames. 10% discount. On thirteen eonsenltlrs Issues, 15% dlscatmt. Carer and preferred-position rates made known on application. Terms: SO dare Not. I* 10 days. CLASSIFIED ADVERTISEMENTS: Plre cents per word. Minimum, 1* words. Dis- count of 10% on 4 consecutive Issues— 15% on thirteen eonsccuUre Issues. Cash with order. Entored as second-class matter. March St, 1911, at the Pest Office st New York, New York, under the set of March S. 187*. IMPORTANT NOTICE: While every possible care Is taken to Stat* osrreotly matters of fact and opinion in technical and ronorsi writtoas severing the radio field, sad every lino printed Is gone ever with s scrupulous regard for the facts, the publisher disclaims sny responsibility for statements regsrdlng questions of patents, priority of claims, the proper working out of technical problems, or other matters that may bo printed In good faith and so Information furnished by these supposed to be trustworthy. This statement la mads in good faith and le ear* time and controversy In matters ever which the publisher eannot peeelblr bars control. Governmental Communi- cation Experts to Meet AT the request of the Department of State each governmental department interested in radio communication has appointed a representative to serve on an inter-departmental committee for the con- sideration of problems of international elec- trical communication. At a meeting, soon to be called in Washington, the several members of the United States Committee will study the problems to be considered at the International Conference to be held in Paris. The membership of the committee follows : Post Office, Paul Henderson, Second Assistant Postmaster-General. War Department, Major-Gcneral George O. Squier, Chief Signal Officer of the Army. Department of Commerce, P. E. D. Nagle, Communications Expert of Signal Corps, U. S. A. Navy Department, Rear- Admiral H. J. Ziegemeier, Director of Naval Communica- tions. In his absence Rear-Admiral Joseph Strauss will be available for this service. United States Shipping Board, F. P. Guthrie, in charge of Radio Service. The State Department representative has not been designated. Subscribe direct or through your news dealer. $6.00 a year, $3 00 six months, $1 50 three months. Radio World, 1493 Broadway, N. Y. C. Quality Design + Workmanship + Materials = RELIABILITY RADIO-A RE -CHARGER This unit is the product of a firm of pioneers in the battery charging field. Our commer- cial apparatus is used in thou- sands of the best equipped battery service stations in the country. Materials and workmanship are the finest available. RADIO "A" is built, not assembled. Simple to use — Just plug in at any 110 v. A. C. lamp socket- attach clips to battery— turn on current and you have your own charging plant. Only one moving part, which will last for several thousand hours. The only Recharger with a one piece Removable Vibrator, can be replaced by a child. Think of the convenience of not having to carry your battery to the Service Station this winter. The Battery will always be full of pep. A compact portable Recharging 'unit that will fully charge a 100 AH bat- tery overnight for 5c. to 10c. A useful and lasting Xmas Gift. Lasts a lifetime. King'EIeclric Mfg. Co., Inc. 1681 FILLMORE AVENUE BUFFALO, N. T. 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RADIO WORLD If 29 ALADDIN ELECTRIC COMPANY, INC COMPLETE RADIO SETS WRITE FOR PRICES. K Wait Broadway, New York City FEDERAL PHONES $C RADIO DISTRIBUTING O & AUTO SUPPLY CO. 64 Weit 66th St, New York City See Mr tMlXl I" Mit lltue Rjdl. Wcrld Recommended by Dealere for Reliability nADIO STORES CORP UNITS, ETC i«m Dipt. 0. 121 Wul »4ta (treat. Hem Ye* Agents ^ LA HOE etAjOJFACTUBBX OF 8H1BT8 winU iiuu to Mil eoouilrte lino of ehlrle dlreet to rarer. Ktdualre v*:Um ^ Bit ralura. No widul er experteaoe required. WrlU for tree MADISON HI II BT MILL* 5«T ltr««.lw«j N«w Tore. N. T. f-bu.. Detectors >3.50 amplifiers Those Broken and Burned-Out Vacuum Tubes Can B e Repaired an. eurmiitMd T**T If your u«. Harvard Radio Laboratories US Hi«h StrMt BOSTON. MASS. TuIk-» returned P.P.. COD. s MICA Aek Your THEY ARE GOOD ^T?SS^Si SHp out the metal diet and ollp In tho WCA- PUONK. Beli.lt— Clearer better Ur« »U oouw WrlU for drrular. Dlaroente to fcbera. MICAPH0N18 orll ta-t Mlaa Products Co.. 151 C. 4 J. »t.. Mow Yore eliminated, dralera and /HU1.T1P01NT (Patent Pondlntl) A ajTithetk- CRI STA I. DETECTOR •mettlT* orer It* entire •nrfo.ro. ■Unlnatai aU detettor troublee 60% Inrreeae to clearneoa and Tolumo. Ee.lorsed by Bs VOl B CRYSTAL DETECTOR I. II aaJiMta In a reread. 1. •easy** awn eeesltlee reeelts. 3. la alowit lorpesalele to Jar oat. Prior tveoty-wri teats oltear. "PT* CRYSTAL CONTACT CO. Box 1841 BOSTON », RADIO MAILING •tT« Retail 1114 1*1* SIT tUmefevgnn. ■anarootarera af eiat- l.par at 144 Bids* ftatioaa par Hat, II*** Boom Aaaetesrre ant Man- aeon of Boom Statteno. . .par at. Kaatta truowrltaoa aad ready ta oood ei reeetpt af reatlttaaoo inert a* la* aaaoaaa. TR.ADE CrRCt'l^B ADDRMHHO hi w AOAm ttun cwicai*. If.M !•.•• 1LH «.M 4.44 oo. Special Socket W. D. 11 Daotmed oopealallj far the new tub* of the Radio OarperaUea which la oteeatod br a atncbi dr» tell. Sperlal ellpa of poao- phor bronao with aide wipe ant etrone rrlpplnf aetiOB OB OOB- uet plna. Nickel plated HaaV lac aerewa. Ulrbaot aoalltr thntuchouL afouldod freaa Ooa- denaltOL ALDEN-NAPIER COMPANY 5J Willow SL. Dept. L. tarlafwaM. Maoa. Novo batterieT FOR RADlJ 22^4-45 & io5y0r_ri N O ISEL E DEPI N DA I J im GUARANTEED ASK YOUR \0\0 MAM FACTLRIN S ' w I'VaQlTK'^ 531 SO DEARBORN ST^CHICAGO REPRESENTATIVES WANTED! RADIO WOm D wanta Ti.ui'e huatlii'K ,ri.,», reprraentatK ra in e«e'y coMefe, orhool. lartorv and bia htikii.rat ,..n,erri i1imi.-ui llr ,.U'tf> ua yau. name aad edUrcae lor lull vailK ulara. KAIMO VMlKI.il mi iiiuetlw Nr. Vurk City Digitized by Google

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JO RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? DEPARTMENT AT U A WORD TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS for ovorybody who wants quick actios an short amaounorments covering tha buying, soiling, exchanging ar Readers of RADIO WORLD wUI And that It pari to raad Ihw column* ovary week. Advertisers will get a tha now stands tan day* altar copy reaches ua. This department la ban ■■ < bandUtng la tha radio ( service horo— that la, copy racatvad for thia dapartaaaat will appaar b* RADIO WORLD Tho rata for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. Is Sc. par ward (mmlmum of U words, discount for 4 consocutivo insertions, 15% for 11 coasscuiivo insertions (» months). Changes wOl bs suds la standing classified at this offloa ton days Mora publication, RADIO WORLD CO, MM Broadway. N. Y. C (Phono, Bryant «7aL) advs^ If copy la of Rogers Radio Recarvere riving Radiaajatsra. Rogers Ra Company, 5133 Woodworth Street, Pittsburgh, Pa. RADIO HOSPITAL. Radio sets repaired by practical radiotrician, and experimentations under customer* • supervision. .*.• Mail orders filled MELCO RADIO, 37-A Bedford Street, New York Oty. ISSUES OF RADIO WORLD from April 1 to Oct. 7 (27 numbers) lor 15c t copy, or the whole lot for 13.15. Or send us $6.00 for one /oar and start with tha first number. RADIO WORLD, 1493 Broadway, New York. PATENTS— Send for form "Evidence of Con- ception" to be signed and witnessed. Form, fee Schedule, information, free. Lancaster andsAU- wine. Patent Attorneys, 259 Ouray Bldg., Wash- ington, D. C. 7 CASH FOR OLD GOLD, Platinum, Silver. Diamonds, Liberty Bonds, War, Thrift, TJ nosed Postage Stamps, False Teeth, Magneto Points, Jobs, Any Valusbles. Mail in today. Cash seat, return mail. Goods returned in ten days if you're sot satisfied. OHIO SMfcl.TlNU CO., 337 Hip- podrome Bldg., Cleveland, Ohio. FRENCH TUBES, genuine (no bootleg with French name), most sensitive and economic (Good for detectors, amplifiers, and especially tor radio frequency. Will work very good on two dry cells.) Price $3.25. ATLANTIC ft PACIFIC RADIO CO., 131 W. 37th St., near Bway., New York. ■ Are you familiar with all the radio symbols used in the various hook-ups published fat Radio World? If not, secure a copy of Radio World No. 26, dated Sept. 23. In this issue was a com- plete table of all important symbols rued la radio construction and testing. Send 13 cents for a copy, or $6.00 per year, and have subscription start with that issue. RADIO WORLD, 1493 Broadway, New York City, N. Y. BRILLIANTONE RADIO PRODUCTS Dept. E, (74 Columbus Ave, New York Oty $3.50 23-Plate Var. Condensers, .0005 $1.75 4.50 43- Piste Var. Condensers, .001 2.25 4.50 Thordarson Audio Amp. Trans 3.00 5.00 B. R. P. Audio Freq. Trans. (11 tol).... 4.07 7.00 U. V. 712 and Freq. Trans. (Radio Corp.) 6.00 6.50 U. V. 1714 Radio Freq. Tr. (Radio Corp.). S.50 .70 Jacks single open or closed (Firth) J5 .90 Jacks double closed (Firth) 50 .002 and .005 Mies Bakelite Condensers 25 .0005 end .00025 M. B. Cond. with Vsr. Leak... .25 .0005 and .001 Fixed Mica Bakelite Cond 20 Tub. Grind Leaks, yi, 1, ltf, 2, % 3 Megohms .45 Arrow Variometer 2.25 B. R. P. Variometer (to 800 Meters) 3.00 180 Degree Vario Coupler (wound Green Wire) 1.65 B. R. P. Vario Coupler (Panel ft Lab. Type) 3.50 Send Money Order, but do not add postage for msiling. Pkg. will come Parcel Post Collect. AMATEURS — Make your own radio sets and "A" and "B" batteries. We supply all parts. Stamp for catalog. Pacific Screw Co., 645 N. E. 53rd St., Portland, Oregon. PATENTS Protect your Invention today. Write for 1921 Illustrated Book Free. Radio, Electrical, Chemi- cal and Mechanical experts. Over 30 years' ex- perience. A. M. Wilson. Inc. (Radio 3 ARH), 310- 18 Victor Building, Washington, D. C (Successors to business established 1891 by A. M. Wilson.) PATENTS— Electrical cases a specialty. Pre- war charges. B. P. Fishburne, Registered Patent Lawyer, 386 McGill Bldg., Washington, D. C Exchange Jdly Interesting Utters through our Chtb I Stamp appreciated. Betty Lee, lac, 4254 Broadway, New York City. RADIO MAN, eleven years' experience in all sides of the game, capable of constructing, in- stalling, operating broadcasting station of any power, desires permanent connection. Go any- where. What can you offer? Evans. Mom us Pier 48, N. R., N. Y. C FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO." Write today for complete list of premiums and our special sub- scription offer. "RADIO," Pacific Bldg., San Francisco, Cal. NEWS AND GOSSIP OF THE STAGE— Seed Ktc for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.08 year, $2.00 six months, $1.00 three months. New York Star Co., 1493 Broadway, N. Y. MURDOCK PHONES-type 56, 3000 ohms... $5.50 MURDOCH PHONES-type 56, 2000 ohms... $4.50 U. V. 200 (Detector tube) $4.50 U. V. 201 (Amplifying tube) $5.85 Postpaid in U. S. Send 25c for 208-page radio manual and cata- logue. A. V. Gregory, 42 Broad St, Red Bank, N. J. SAVE B TO r*% ON ALL SUPPLIES. WE SELL SUPPLIES ONLY. LARGEST STOCK. $1.50 Round Telephone Plug, 79c; Flat, 60c K.0O Arrow Variometer, $3.90. Moulded black Variometer, $4.75. Six Dollar Manhattan Tele- phones. $4.40. Best Quslity V. Condensers with Dial, $2.35. MONEY BACK Guarantee. Include postage. AMALGAMATED RADIO SUPPLY COMPANY, 193 A WILLIAM STREET, NEW YORK CITY ASTONISHING results Rokay Regenerative Hook-up without use of Variometers — variocouo- lers. switches, taps, etc. ONE SINGLE CON- DENSER CONTROL ONLY. The coming re- ceiver. Simpler than a non-regenerative— better than any regenerative we have tested. Hook up. $1.00. Money Orders only. Saves you $10.00 ia building your own. With properly wound coils. $3.50 post paid. Complete receiver parts on wood base with Vacuum Tube, $8.00. Head set and "B" Battery, $21.35. Express paid. Rokay Elec- tric Co., Ingomar. Ohio. WANTED « COPIES of RADIO WORLD, April 22 and May 28, 1822. Mail us copies of these issues, or either one, with an sccompsny postal and we will send you a copy of the latest issue for esch copy so mailed. RADIO WORLD, 1493 Broadwsy, New York. ARMY FIELD GLASS $12. Cost $35. G. WALKER, Box 633, Cincinnati. HIGH GRADE Radio Apparatus greatly reduced. Manufacturers and jobbers needed cash; hence these low prices. Standard heavily nickel-plated De Luxe Condensers, 43-plate, $1.95; 23-plate, $1.75. Condenser parts complete, 43-plate, $1.75; 23-plate, $1.50. Binding posts, 3c. Best 3-inch Dials, 40c (3 for $1.00). Switch points and nuts, 15c. dozen. Stops, 3c esch. Grid Leak Condensers, 10c "B" Bat- teries, large tapped, 22yi volts, $2.00; small, $1.00. The above goods sent postpaid upon receipt of J trice. Your satisfaction is our assurance of uture business. NEW YORK RADIO OUTLET. Hempstead, N. Y. READ about Stamps, Collectors and Dealers in "The Albemarle Sump Collector," Bethlehem, Pa. Latest issue free. AGENTS— Make two dollars an hour. 33c profit on every 35c sale. Sells on sight Sample free. Empire Branch, 7201 Atlantic Ave., Ventnor, At- lantic City, N. J. VERY INTERESTING printed matter on de- tectors and crystals. Sent on request. Midland Electric Mfg. Co., Indianapolis, Ind. BROADCASTING MAP of the United States appeared in RADIO WORLD No. 8. Sent on re- ceipt of 15c coin or stamps, or start your sub- scription from that number ($6.00 for 52 issues). RADIO WORLD, 1493 Broadway. New York. VARIOCOUPLERS AND VARIOMETERS at a bargain. Write for circular. Alexander Jurek. 2642 Ballou St., Chicago, III. ACT QUICK SALE. Oak Cabinets. 6x6*4x12, with genuine 3 16 Celoron panel, $3.75. Haupt Radio Supply Co., 2442 Ogden Ave., Chicago, III. Manufacturers of Rogers Radio Receivers and Rogers Receiving Radiometers. Rogers Rsdio Company, 5133 Woodworth Street, Pittsburgh, Pa. DO YOU USE A CRYSTAL DETECTOR T ARE YOU MAKING A CRYSTAL RECEIVER T In- crease the efficiency of your crystal detector 1.008 per cent by using a "PT" Ultra-Sensitive Coo- tact Of special gauge and alloy; makes and holds a quick, ultra-sensitive, stsble, adjustment. Endorsed by RADIO WORLD. Using galena, yon msy pound panel or table without disturbing sen- sitivity in slightest. Proved practical on ship- board by an oldtime Marconi operator. Using a "PT" Contact on galena, Arlington (NAA) was brought in clear at 3.300 miles (below the Equa- tor); snd Arhnrton csme in loud at 2.200 miles (off Dutch Guiana). In both Instances, nssirhj ships using vacuum rubes ware unable evsn to hoar NAA. As to stability. Cape Msv (WCY) wss worked over 1.000 miles, sanding right through crystal with 2 KW spark, without affecting detect- or's adjustment. Replace your insensitive unstable spring or catwhisker with a Contact which win hold its sdjustment In sddition to giving louder signals and music. Indispensable for use in yon- crystal set regardless of make. A novice can rv^wJl.^T1"'. iTyr*A-SWNSrnVE DETECTOR CONTACT, with Instructions, twentv five cents 2"n °X..M^°- CRYSTAL CONTACT CO.. Box 1641, Boston 1 Massachusetts. Broadcast Bill's Radiolays By WUliam E. Douglass T7»OUR years ago 01' Kaiser Bill got V scared an' yelled, "Enough," because he said the enemy wuz treatin' him too rough. An' so in Brussels Sprouts each year we aim to celebrate November the eleventh as a most important date. It seems like it's been forty years instead of only four since we wuz in the Argonne wishin' we could end the war. In June of nineteen eighteen I wuz down along the Marne so blue an' doggone homesick that I didn't give a darn what happened. Then the orders came fer us to go up front an' bein' sorter v ' !< ss that's the time I pulled the stir ":n' in some Heinies an' I got It made the home-folks here in town all mighty proud of me — that's why the Armistice Parade is run by Private Bill. I've run it now fer four years an' I guess I always will. As long as I've been doin' it things never have gone blooey. Sometimes I think I'm smart enough to be a second Lieuie. Now take fer instance this year, my scheme worked out purty nice, it didn't cost me very much but it was worth the price. I had my radio hooked up in the reviewing stand an' then "picked up" a station where a Military Band played patriotic music. I left Min to watch the set ; the celebration this year wuz the best one we've had yet. I had the Brussels Sprouts police head up the big parade. Yep, both of them right in the front, no need to be afraid of traffic interferin' when we're marching down the street. T tell you in their uniforms our cops look pretty neat. Then come the Golden Cornet Band, they made a lot of noise an' marchin' right behind them wuz the Hook an' Ladder Boys; an' then some flivvers all dolled up in red an' white an' blue— Chuck Walker had to butt in here just 'cause his car wuz new. An' then I an' my buddies finished up the grand procession. Our luck wuz breakin' mighty good to make a fine impression, fer just as we got up to where my wire- less set wuz playin' we heard Star Spangled Banner an' it goes without my savin', I had the boys halt on the spot an' yelled, "Comp'ny attention I" Believe me this here Radio's a wonderful inven- tion. (Copyright 1922. Westinghouse Electric ft Manu- facturing Company.) Digitized by Google

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RADIO WORLD How to Make a Decremeter Figure 1— TbJa diagram may ba cat out mmd uaad a> IN Radio World, No. 32, dated Novem- ber 44, there was published, complete, an article of first value to radioists en- titled, "Wave Meter for Amateur Opera- tors," describing how to construct the device which enables one to adjust his set tnd comply with the law. This article was prepared by the United States Bureau of Standards experts. Frequently it is necessary ' to employ a decremeter with a wave meter. It is possible to make a decremeter out of a wave meter by placing a suitable scale on the variable condenser. For a wave meter Variometars with dial, $238 Vaxiocouplers with dial, IMS Post Paid Money Back if not SatUfactoty OSLAND, INC 122 FIFTH AV. Maaafattsrsrs NEW YORK R. P. G MIDGET RAblO POCKET RECEIVER Size 1-11-32x3^x6^ Price $3.00 THE R. P. C. MIDGET POCKET RECEIVING SET is designed to meet the wants of the novice (an opportunity to get acquainted with the mysteries of the RADIO ART) and who, having learned the ABC of Radio, may readily become a more serious student of this most important field of investigation. This receiver is made of the finest material. It is mounted in a pol- ished wooden case, fully equipped with a FIXED CONDENSER for tuning. It has a range of approxi- mately 25 miles of clear distinctive receiving. THE R. P. C MIDGET is truly the wonder of the age in size, price and quality. Not a mere toy but a scientifically built Crystal receiving set comparing favorably with many higher priced sets on the market* Without head phones, $3.00 post- paid everywhere. Discount to Jobbers and Dealers Radio Products Corporation of America B Browhrar. New York, U. S. A. haring a condenser with semi-circular plates or any condenser such that the graph of its capacity against its setting is a straight tine, the capacity being very small at zero setting, it can be shown that the decrement scale to be used is one in which the graduations vary as the logarithm of the angle oil rotation. Such a scale, designed for a semi-circular plate con- denser, is shown in Figure 1. This scale may be copied, or cut, from this issue of RADIO WORLD and trimmed to fit the dimensions of the condenser dial with which it is to be used. It may be made stationary with a mov- ing pointer traveling over it, or ' it may be mounted on a dial rotating under a fixed point- er. At the setting corresponding to maxi- mum capacity the scale reading should be be zero. Since the scale- of most condensers read counter-clockwise, this arrangement us- ually places the decrement scale in the un- used space opposite the capacity scale. A measurement of decrement is made by first observing the current squared at reson- ance, then reading the decrement scale at the settings on either side of resonance where the current squared has one half its value at res- onance. The scale is so constructed that the difference between these two readings is equal to the decrement of the transmitting circuit rlus the decrement of the wave meter itself, t is then necessary to subtract the wave meter decrement from the total just obtained. The decrement of the wave meter is deter- mined as follows: the wave meter is coupled and tuned to a source of unmodulated continu- ous waves. The sum is measured as jutt nm\i% I Marly IS to 39 alto*. OmMs taasr. Eaalfstd vita Ik* sadly asllarM "Das-tost" astsstor. la a asat Oasfr Oalasai bt>. sisiir Csapwto alto srystol *7.J0 Wltk asrial. salt**, laialstori. raporlally aaaal •"d for tbr m Arm.troac Kanrr llsaiai rratlr* rirrult. M roas raasa la all raparlilra from .ftooo? 3 ta .01. At yaor dralrr. athwart— and par- rhaaa prtr* and tha dmdrrd Mlraaa will b* arat wlthoot farther rharaw. CHAS. FRESHMAN CO, Inc. »7 Brrkman St. New York City SEND IS THE NAME OF YOUR RADIO CLUB Ai.o n.im wnr.i tn a.M ihrv to • II. t „f rn.lln clubs nnrt nfflr.-r. ur nr.- pr. paring for pu',11. jtion In an r»i\r • it turn \\. ll!>3 Broadway. N*w Tork. 7 """" Digitized by Google

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RADIO WORLD Orange Label Tea Special lOf Tins Has a body to it that men like! For smacking flavor, delicacy of aroma and a cheerful invigorating influence, drink the best tea - Ridgways Tea. Also sold in / lb., V2 lb. and V4lb. TINS A Gen ;roui Sample will be sent on request. Address: Ridgways, Inc., Department K, 60 Warren St., New York. Wguays OLD MEDAL San Francjpco 1915 GRAND PRIZE San Diego 1916 Digitized by Google

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Ladio Wee December 23 to 30 (inc.) (Trad* Mark) ILLUSTRATED. WEEKLY Field Sets Used by U. S. Navy :Pfc ^ .. 1PM i .V 'I ^ 4 ' — V (C Underwood & Underwood, N. Y.) Here is a transmitting set used exclusively by the United States Navy. It should be of interest to every radioist. It is different from sets in ordinary use in this respect: It is made so that it fits in a suitcase, making it possible to carry it ashore for land duty. In the left of the photograph is the transmitter1 with its compact inductance coils, making it possible for the operator to broadcast on a wave-length fixed for any particular purpose. With radio transmitters, high voltage must be secured to apply to the necessary tubes. In this case, a special machine is used as shown at the right to supply this power. le Counterpoise Explained, by Frederick J, Rumford

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RADIO WORLD The whole world is at your fireside when you own a Grebe Receiver. Ten years of radio manufacturing experience has taught us the importance of simplicity. Recom- mended by most good dealers because they know the shortcomings of ordinary apparatus. Ask your dealer for a demonstration. Get your copy of "Musings of Dr. Mu"- the story of the development ot the Perfect Receiver. A. H. GREBE 8C CO., Inc. Richmond Hill, N.Y. Digitized by Googl

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VOLUME TWO RADIO WORLD [Entered as leoood-elsee eutter, Kerch X, 2922, at the Feet Office at New York, N. Y., A WMkly Journal, ftiblubed Ewery Wednesday and Dated Saturday, by Corporation from Publication Office, 1493 Broadway, New York, N. Y, the act of Kerch 1, U79J Telcpbonet Bryant 47ft. Vol II, No. 8, Wbole No. 34 November 18, 1922 15c per copy, $4.00 a year Radio Devices You Should Understand THE lower picture shows El- man B. Myers, inventor of the Myers vacuum tube, pho- tographed with his new radio- receiver. Mr. Myers is using the well-known circuit of radio fre- quency— three stages of radio fre- quency before the detector tube with which to amplify weak signals. When weak signals are amplified after having surged their way through the three amplifying tubes, they are then sent through the de- tector tube for rectification. The detector tube rectifies the radio fre- quency to audio frequency, making it possible for the signal to be heard in the telephones. After the detector tube, Mr. Myers employs three more Spark transmitter and Irydm-Jar (C. International News Reel) . Myers with apparatus for three stages of radio- end audio- frequency. stages of audio amplifiers. With 3 radio-frequency amplifiers, 1 detec- tor, and 3 audio- frequency amplifiers. Mr. Myers should hear everything. The radio transmitter shown in the (upper) larger photograph is one of the old- type sets that r^adc its appearance about six years ago. The explanation of the numbers is as follows: 1. The pair of meters for registering the motor-generator. 2, The quenched-spark gap. 3, The power transformer. -4. The leyden Jars, bettei known as the rondemer-. 5, The hot-wire ammeter. Digitized by Google

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4 RADIO WORLD The Counterpoise Its Advantage as a Complete Reducing Agent in the Resistance of the Antenna Fully Explained By Frederick J, Rumford, E.E., R.E., THE counterpoise is a sadly neg- lected hook-up. Few radioists have experimented with the counterpoise since Sir Oliver Lodge, as far back as 1890 made a number of experiments. The advantage of the counterpoise for the receiving station is a general complete reduction of the resistance of the antenna, or aerial, which with this reduction would result in a decided decrease or lowering of the decrement of the circuit, or cir- cuits, in use and would increase greatly the circuit, or circuits, selectivity which would also increase the intensity four- fold or more. The writer in one particular instance of experimenting found that with one of his many experimental antennas and counterpoises he had decreased the resistance of the circuit from about 50 ohms down to about 8 ohms when he had used the counterpoise instead of the usual water-pipe ground connec- tion. Radio fans who live where the earth is very dry should try one of the counterpoise connections illustrated in the four figures accompanying this bO'lOO'-ISO1 article; for the earth being dry, it functions very poorly as a ground con- ductor of radio waves. Figure 1 represents the antenna and the counterpoise as erected — when the antenna is on the roof — on the usual masts or poles. Should the antenna be mounted on poles about 12 feet from the roof top with the counterpoise exactly 6 feet below it, the method of mounting is as fol- lows: The antenna should be either or 1 or 2 wires — No. 14 bare copper or any other good aerial wire — from 60 to 100 or 150 feet long, spaced about 3 feet apart. That is, if 2 wires are used with the usual insulators at each end, the coun- terpoise should be 6 feet under the antenna. If possible, it should be several feet longer than the aerial and spaced about 4 feet apart, if 2 wires are used. The method explained above is for the fan who hasn't the space to erect his aerial on mast from the ground up; who, by necessity, must have his antenna on the roof. Figure 2 shows another method of making an efficient antenna counter- poise. This method is for the fan who has plenty of room to erect his an- tenna on masts implanted in the ground. This counterpoise may be of either 1 or 2 strands of No. 14 bare copper or any other good aerial wire. It should be at least 30 feet high from the ground's surface and either 60, or 100, or 150 feet long. If 2 wires are used, they should be spaced from 2 to 3 feet apart and the counterpoise should be mounted about 6 feet from the ground. If possible, it should be several feet longer than the antenna. At the double end, these wires should be spaced at least 5 feet apart. This type conterpoise is known as the V anti- ground conductor. If this type is chosen, the writer feels certain that the prospective builder will have no rea- son to be disappointed. Figure 3 shows another view of the antenna counterpoise which may be erected where one end of the antenna and the counterpoise may be con- nected to the attic or the weather-head of the house by means of suitable in- sulators, and a pole of 30 or 40 feet high and 60, or 100, or 150 feet from the house. The antenna in this par- ticular instance, was 1 No. 14 bare copper, or any other efficient aerial wire, with its respective insulators. At either end, the counterpoise is of 2 wires spaced about 3 feet apart and, i f possible, several feet long. The an- tenna should be erected about 7 feet from the ground so as to not interfere with anything passing beneath it. It is insulated at either end with the usual insulators. This hook-up has proved W/OO-'/SO' antenna and counterpoise as erected when the antenna of the house. Suggested by Frederick J. Rumford. Drawn by S. Newman. Figure 2— Another method of erecting an efficient antenna counterpoise. This method is for the fan who has plenty of room. Suggested by Frederick J. Rumford. Drawn by S. Newman. Digitized by Google

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RADIO WORLD 5 Changing Inductance and Capacity By Fred. Chas. Ehlert Radio Don'ts DONT hook-up a pair of poor phones with a good receiver. Don't drop the ear pieces on the floor. Keep the magnetism intact. Don't take the covers or caps off just to see the inside. Leave well enough alone. Don't add a loud-speaker to any type of crystal receiver. Don't expect an amplifying horn to produce the same results as a loud-speaker. Don't connect the house lighting-current to your tubes. Don't forget that rheostats are used to light the filaments. Dent apply too much current to the filament. Don't use plate batteries to light the filament, Don't expect too much from a crystal receiver. Don't touch the mineral in the detector with your fingers. Don't use lead or solder in mounting the mineral. Don't be afraid to occasionally clean the crystal with alcohol. Don't forget that a fixed adjustment on a mineral detector will not hold its sensitivity per- manently. Don't leave your tickler coll at maximum with your tube oscillating and generating radio- waves. Don't insert condensers in series with the ground and expect to increase your wave length. THERE are various methods of changing inductance in a circuit. A straight wire has very little in- ductance. Make a coil of the same wire and the inductance is considerably in- creased. The coil may be made either by winding it smoothly over a form, such as a broomstick, or by winding it spirally in the same place. Electrician's tape may be purchased in a roll. The inductance of a coil' is changed by changing the number of turns of the coil in the circuit. There are, also, various methods of changing the capacity in a circuit. A second method is by changing the ca- pacity of a single condenser. This is done by having both sets of plates that make up the condenser movable in respect to each other. When every part of the plates in one set is opposite the plates in the other, the capacity is the greatest. Capacity is made smaller by having only a part of each plate in one set opposite the plates in the other. The inductance and capacity needed in an oscillating circuit is contained in the antenna of a radio transmitter. The antenna of radio set is that part of the set which radiates the energy by setting up the waves in the ether as explained. The wires making up the antenna give both the capacity and inductance. {Continued from preceding page) very practical, but it is mostly for the fan who has the space to span his wires any number of feet from the house. Figure 4 is the antenna counter- poise the writer experimented with and which he found efficient, reliable, and practical. This antenna counter- poise is intended for fans who have any amount of space at hand in order to erect it complete. The instructions : Erect 2 masts, or poles, of some sea- soned wood ; or, better still, erect 2 steel towers. These should be from 30 to 60 feet high and spaced 60, or 100, or 150 feet apart, to suit the con- venience of the prospective builder. One wire, either No. 14 bare copper or any other efficient aerial wire, should be stretched from mast to mast with suitable insulators at either end. The counterpoise is then erected about 7 or 8 feet from the surface of the ground. It should be several feet longer, if possible, than the antenna and should have suitable insulators at either end for perfect insulation. It must be placed sufficiently high from the ground so as not to interfere with anything, passing under it. The following are necessary in the erecting of any of the above antennas or counterpoises. They must be thoroughly insulated from the ground. The lead-ins must be thoroughly in- sulated from the ground. The counterpoise lead-in connected with the ground is usually connected up on the reciving set. The writer feels certain that the builder will not meet any great diffi- culty in erecting one of the counter- poises described, but if he does, I will answer gladly any questions that he may ask, if accompanied by a self-ad- dressed, stamped envelope. t> Antenna 60' 100'- ISO' Antenna 60'-IOO'-l50 "tore J— The antenna counterpoise so erected that one end of the antenna and the counterpoise may be connected to the attic of the weather-head of the house by means of suitable insulators. Suggested by Frederick J. Rumford. Drawn by S. Newman. Figure 4— An antenna counterpoise that was found efficient, reliable and practical. It is for fans who have plenty of space in which to Suggested by Frederick J. Rumford. Drawn by S. Newman. Digitized by Google

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6 RADIO WORLD The Importance of Understanding and Testing Radio Apparatus By C. White, Consulting Engineer Radio tasting apparatus used by Mr. C. Whits in the testa described in this article. THE general practice of scientific- laboratory testing and research has been neglected in the radio field. While it is quite true that certain manufacturers have taken special in- terest in the practical trying-out and testing-station work conducted by various scientific and semi-scientific journals, still there are comparatively few who have actually put themselves to the additional trouble and expense to have a definite line of scientific experimenting on their apparatus. Although an actual try-out will bring to light many of the serious inherent troubles in a radio receiver, yet, owing to the uncertainty of varying atmos- pheric conditions, it is utterly impos- sible to determine the absolute or definite relative value accurately by such methods. We are about to enter upon the second year of our unusual radiophone popularity, and it would do well for many of us to think over the problems that must be solved if the wireless science is going to progress. And the most important problem we are facing for solution is the development of more supersensitive receivers. From developments and inventions brought forth during the past year we do know that, by means of more sensitive re- ceiving apparatus, we could be able to receive from stations (radiophone) at least 5,000 miles or more distant. At present such a feat — if, indeed, it could be fully realized — would be con- sidered a miracle. Research is more than testing for defects in goods already manufac- tured; it is the searching out of new and fertile fields for development, on the border line of the unknown. For the past year I have been trying out — by means of definite and well-founded scientific principles — the comparative values of the different amateur receiv- ing sets on the market. To receive from a certain station is not a very good test for a receiver because, perhaps, reception was due to some freak atmospheric condition, under which even an ordinary crystal set is said to produce marvels. Not even the repeated reception from a certain dis- tant station can be taken as a good basis of judgment, for the quality of the received signal will largely depend on the amount of power received and the modulation of the transmitter, all of which is quite variable from day to day. So, in conducting this work, it was very necessary to construct within the narrow confines of our laboratory a small sending-station which we could absolutely regulate and control to give us various amounts of power. In other words, we tested out the various receivers on what might be called a phantom signal, and by care- fully arranging and shielding the various pieces of apparatus used we could quite effectively try out our theories and delve into the troubles in present receivers and at the same time compare them with newly developed circuits of our own. In Figure 1 is illustrated two types of oscillators used in our receiving experiments. The one shown on the right used honeycomb coils for tuning inductances, while the apparatus on the left makes use of ordinary inductance coils so wound as to cut down to a minimum point distributed capacity. The former is a better oscillator for short waves, especially since it is wired up for two types of oscillating circuits, thereby allowing close and quick check operations by means of two tumbler switches. We obtain an artificial modulation by placing the secondary of a small modulating transformer (audio-transformer) in series with the plate potential supply (the B battery). The primary of this transformer is fed from a small 780-cycle alternator. So. theoretically, all we do is to impose a 780-cycle audible note on the high radio-frequency carrier wave. The output terminals of our oscillator are Digitized by Google

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RADIO WORLD 7 Do Not Force Power Tubes By Peter Gray IT is unwise to overload or force a radio- tron power- tube, as its operating life will be menaced. It is a better plan and more economical to operate two tubes in parallel than it is to force one tube to deliver a power output far in excess of its rating. Economy will result from burning tubes slightly below normal brightness — to double the fila- ment emission wilj reduce the operating life of the tube one-half. Burning the tube at 95 per cent of its normal brightness will mul- tiply its life fourfold. When first testing the circuit, or when the set has not been operated for some time, cut down all voltages to one-third of the normal voltage. This will greatly reduce the pos- sibility of burning out the tube through a wrong connection which has been overlooked. The fault will then instantly be detected be- fore the damage is done. In a radiotelephone transmitting circuit a modulator tube is employed and a buzzer sub- stituted frequently for the microphone to send out interrupted continuous waves. This imposes voltage strains on the oscillator tube. Important Insulation Necessary IN powerful C-W transmitting sets, the cir- cuits should be so arranged that the center up on the filament coil and. also, the nega- tive lead of the direct-current high- voltage source are both at ground potential relative to high-frequency potentials in order to in- sure safety. Great care should be taken to thoroughly insulate the grid and plate leads to the tube and the coil sections connected to these leads or to any apparatus in them. He Built This Set for $21 (C. Kadel & Herbert) The above is a photograph of Charlas Murphy, radio student at Fordham University, New* York, completing; a regenerative receiver with one stage of amplification, which cost him SZ2. With this sat Mr. Murphjr can hear the distant stations. Br means of the Armstrong circuit which is produced by the aid of tha variometer In the plate circuit feeding beck the energy into the grid circuit, and a condenser, ho ia able to eliminate tha taps on the coupler of this receiver. For a detector tube, he is using an old audiotron-tube and a V-T No. 1 as as ampli- fier. 1 is the amplifier case containing the detector tube and the amplifier. 2 is the detector tube. 1 Is the variometer in the plate circuit. 4 ia the varaUe condenser. S ia tha coupler,, with its peculiar winding. ( shows tha method of soldering a connection in tha amplifier. 7 is the amplifier tube or the V-T 1. These comprise the complete receiver. (Continued from preceding page) fed through a mutual inductance coupling, which is nothing more than a specially constructed vario-coupler, to the antennae and ground terminals of the receiving set to be tested. By this method we not only control the frequency of the modulating circuit, but we can carefully control the rela- tive amplitude of both the audio-wave and the radio-frequency carrier wave. Therefore it is quite easy for us to actually assimilate a nearby, or distant, station by so doing. The brief outline of this method clearly shows the theory behind the operations, but there are many practical points and considera- tions that must be fully taken into account before a good and authori- tative comparison may be materialized. First, we must carefully intershield all of the component apparatus we are employing in the test hook-up. This does not only include a complete shielding of the generators, radio-fre1 quency oscillators and audio-frequency alternators, but all the parts of the oscillator. In addition to this we must place the audio-frequency set in another room to get rid of its noise, and we must cany out the tuning and audibility test on the receiver in a specially screened-off corner of the laboratory. After all apparatus for generating the phantom signals are adjusted and set in operation the tester must crawl into his screened-off cage with the set that is under consideration. Generally a well-planned selectivity test is carried out to determine the relative amount of selectivity by means of slightly changing the wave-length impressed. Next, the audibility of the volume received is measured by means of an instrument known as the audi- bility meter ; then comes the distortion test. This test is accomplished by photographing the wave-form of the audio-frequency wave as generated by the high-frequency alternator and then photographing the wave-form as re- ceived by the phones. The actual photographing of this wave is done by the aid of an oscillograph — an instru- ment that traces with light the wave shape of an alternating electrical- impulse. It has been proved by prac- tice and experience that a good set, or circuit, may be readily picked out. Not only has it been able to measure volume and sensitivity, but it has been possible to incorporate many important design changes while the set was on test with- out the long and tiresome method of sitting up for half-a-dozen nights to get a good average of its new per- formance. Although this method of testing is by no means fool-proof in operation, manufacturers who lack facilities for such work avail them- selves of such service, for it is well understood that many improvements can be made on the best outfits While I have only outlined the phantom reception test, there are many more tests — resistance, inductance, capacity, and leakage tests — that lack the complexity of the one previously outlined, yet they are quite essential and important. If we intend to perfect radio for the home, just as the kodak has been simplified and perfected, we must carry on more aggressive re- search. It is not enough to hitch a set up to an aerial and turn the dial until a sound is heard. We must do more. We must investigate relatively the volume and the tone quality of the same. We must try out different types of arrangements and see if the general quality can be improved. The modern radio amateur is quite willing to. accept the better grade of goods, and it will not be long before he not only will request a better scientific instrument for his home, but he will demand it. Since we are facing National Radio Week let us all- manufacturers and amateurs — turn to the right and realize the possibilities of radio for home and business. Digitized by Google

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8 RADIO WORLD Radio Takes on More Wartime Duties Signal Corps Radio Direction and Range Finders Will Aid in Coast Defense and Extend Distances WASHINGTON, D. C— The ranges of the shore-defense guns of the United States in all probability will be extended twenty- five miles farther to sea by virtue of a newly developed radio range-finder now being tested on the Atlantic Coast. Previously the maximum range of the great coastal guns was approximately twenty-five miles when visibility was good, but with the perfection of the signal corps radio devices poor visibility is not a handicap, and it is expected that a maximum range of about fifty miles can be reached, pro- vided the guns are elevated high enough to be fired that far. Enemy ships will have to stand farther out at sea to be safe; at least, the fleets will be prevented from anchoring or disembarking troops within fifty miles of our shores in wartime. Employs Radio, Aviation and Plotting Three factors make up the essential principles of the new long-range fire control — radio, aviation, and plotting. For the first time in history the post- war developed radio-compass will be employed for a purpose other than to locate stations or give ships their bear- ings. The use of an airplane equipped with radio for spotting the fall of pro- jectiles is not new, but the unique fea- ture today is the fact that the airplane itself will be out of sight over the target or ship. Without awaiting the fall of sighting shots the observer will send a series of radio signals which By Carl H. Butman {Copyright, 1922) will make it possible on shore to plot the successive positions of the ship and determine its course and speed. One of the problems of the joint coast artillery and air service maneuvers, now under way off the Virginia Capes, was a test of the new radio fire control devices and a com- parison with the old method. A boat visible from the shore will run various courses in an area several miles wide, stretching seaward from Cape Charles and Cape Henry, the master of the vessel keeping an accurate time record of his course and speed. An airplane from Langley Field equipped with radio-sending apparatus will fly out, locate the ship, and remain over it as much as possible by executing the figure 8 in the air. Flying at a height of several thousand feet, calculated to be safe from anti-aircraft fire, this observation plane will send special signals to the shore only when it is exactly over the vessel, continuing to do so until ordered in by the shore stations. Radio Direction Station* Ashore Get Signal* On shore two radio-compass stations, several miles apart, have been set up and direct lines of communication laid to the batteries. Operating just as when a ship's bearing is furnished these two stations will pick up the signals sent by the observing plane when it is over the target ship. In other words, they will turn their com- (l^anoon by Lawrence B. Hinckley) RADIO ON THE FARM HAS ITS DRAWBACKS 'I'M: "I wonder what kin be wrong with this contraption I Just about this time every night it seems to pick up some very familiar noises. pass coils until the radio signal is re- ceived with equal strength in both receivers, then the direction, or angle, from the stations will be read and plotted. With the angles at each station read simultaneously, and the distance apart known accurately, it is a simple problem in trigonometry to locate the position of a ship and its distance from the battery. It is even simpler to plot the location of the ship on a map by laying down the angles from the two stations, extending the lines and noting their intersection. Within a few seconds a second signal comes in, then another; all of which, when carefully plotted and timed, give the course of the moving target and its speed. Firing at Unseen Targets Miles Away Firing may or may not be under- taken in the initial test. This does not matter, as it is solely a problem of ordnance and ballistics after the ship's course is plotted. The artillery men do the rest, although they see nothing of their target many miles at sea. The most important feature of the scheme is its adaptability to night operations and in thick or foggy weather. Con- ditions do not matter so long as the observing plane can find the ship and fly over it. The distance from shore does not matter; but the range may be increased over the old range, limited by visibility from the observing towers, planes, or balloons ashore, by many miles beyond the horizon. A comparative test made by another plane flying nearer shore will also be made; but as the data this observer can give will be only in the form of estimates as to the bearing, or azimuth, of the vessel, and its distance from Fort Munroe, it is not thought this old method can furnish the plotters with sufficient accurate information to com- pare with the more exact radio direc- tion finding system. Cooperating with the board of coast artillery and air service officers con- ducting the test, Captain G. W. Morris, of the Signal Corps, is in charge of all radio operations during the first tests of the army's new radio direction finder now applied to gunfire. Among other experiments to be con- ducted during the week will be tests to determine the extent of interference to radiotelephone and telegraph mes- sages caused by neighboring radio communications in operation. Digitized by Google

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RADIO WORLD 9 Operating a Three-Unit Honeycomb Regenerative Receiver A TYPE of tuning apparatus, op- erating under the inductance principle, is the honeycomb-coil unit. These coils are single units and are used in conjunction with the adjust- able mountings, the coils with the mounting making up the tuning unit. Similar mountings are made for the two-coil unit. When the honeycomb-coil mounting is used, the same advantage is taken of electrical phenomena as in the case of the vario-coupler and the loose-coupler, that is, oscillatory current flowing through the honeycomb coil, which acts as a primary, creates magnetic lines of force. When flowing through the sec- ondary coil, the lines of force induce a current. As the angle is changed be- tween the two coils, the magnetic lines of force affecting the secondary is varied. Therefore, the angle, or ad- justment, of the secondary controls the magnetic lines of force. Instead of tapping the coils, a num- ber of honeycomb coils must be on hand to be inserted — as the length of the broadcast wave requires. A three-coil schematic diagram is shown herewith, in which the third coil is used in the plate circuit to produce amplification. A table published in Radio World, No. 32, dated November 4, showing the different coils needed to receive from the various wave lengths. To operate the set, light the filament of the tube to as near brilliancy as pos- sible, the tickler coil being set at zero. Increase the brilliancy of the tube until the hissing sound is heard in the ear pieces. When this is heard, decrease sufficiently to stop the hissing. Set the coupling at maximum and the primary and tickler at its lowest value. Then, very slowly, vary the secondary coup- ling from zero to maximum. If no signals are heard during this operation, change the primary setting five or ten degrees and vary the sec- ondary through its range. Do this un- til signals are heard. If they are not heard, increase the tickler setting and repeat When the signal has been heard, adjust the controls for best re- sults, remembering that, in order to ob- tain selectivity or freedom from inter- ference, the coupling must be decreased considerably to zero. This should be done gradually in order not to lose the signal. The tickler coil may be increased to best position, but not so far as to oscil- late, as oscillation spoils the signals. By John Kent LwwJ 0002/ i rVVVVWW f! Battery i 6 Volts' SdMnatic diagram showing hew a third coil ia uaad in tha plate circuit to produce ampUncation. Oscillation becomes a small generator of high-frequency currents. In turn, this current acts as a transmitter caus- ing current to be sent out similar to that of a sending station. Whenever hissing sounds, varying in pitch, are heard, it is a certain sign that some re- ceiving station nearby is radiating waves because its tickler coil is turned up too far. When attempting this hook-up, be careful to watch each connection in order to be certain that the right polar- ities are made. Radio Laws and Regulations of the United States THE owner of an amateur radio- transmitting station most obtain a station license before it can bo operated if the signals radiated there- from can bo heard la another State; and, also. If such a station is of sufficient power as to cause interference with neighboring licensed stations la the receipt of signals from transmitting stations outside the State. These regulations cover the operation of radio telephone stations as well as radio telegraph stations. Station licenses can be Issued only to citizens of the United States, its territories, and depen- Transmlttlng stations must bo operated the supervision of a person holding an Operator's License. The party In whose name the station is licensed la responsible for its activities. Government licenses granted for amateur sta- tions are divided into three rlassei as follows: SPECIAL AMATEUR STATIONS known as tho "Z" class of stations are usually permitted to transmit on wave lengths up to approximately J7S meters. Prevent Tube Accidents THE principles of construction and op- eration in the larger power-tubes are no different from those applying to the smaller ones. Many effects negligible in the smaller GENERAL AMATEUR STATIONS which are permitted to use a power input of 1 kilowatt and which cannot use a wave length la excess of 2»t meters. RESTRICTED AMATEUR STATIONS are 1 located within five nautical miles of Naval stations, and are restricted to H These stations also camw lengths in excess of 2Sf meters. EXPERIMENTAL STATIONS, known as the "X" class, and school and university radio sta- tions, known as the "Y" class, are usually allowed greater power and also allowed the use of longer wave lengths at the discretion of the Department of Commerce. AD stations are required to use the minimum amount of power necessary to carry on successful communication. This mssns that while an ama- teur station ia permitted to use, when tho cir- cumstances require, an Input of 1 kilowatt, this Input should be reduced or other means provided for lowering the antenna energy when communi- cating with nearby stations, ia which case full Is not required. tubes are magnified in the larger tubes, and certain precautions are necessary. Accidents to power tubes and their auxiliary apparatus occur during the period of development of circuits, testing, and adjustment rather than during operation. Digitized by Google

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10 RADIO WORLD The Radio Primer Useful Facts for the Begir For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks W HAT is capacity? The condition of the earth constant. This is because Capacity electrical is it has a limitless capacity, is an important factor in work, and it is necessary that we have a thorough understanding of what it is. In order to thoroughly understand capacity let us take two metal balls, one twice as large as the other. Put twice as much electricity in the larger ball as in the smaller one. Now, if ■DOCTORS Inductance TtWo cmci/iT. Jf I Cakmity Schematic diagram of a condenser and radio cir- cuit. Nota the insulator and the conductor with the negative and positive charges. we connect the two balls by a wire there will be no change of electricity. There can be no difference of potential (voltage) between them, or there would be a transfer of electricity ; that is, the two balls have the same potential and it will require twice as much elec- tricity to bring the larger ball to this potential because the larger ball has twice as much capacity as the smaller ball. * * * What is the use of capacity? Capacity is the ability of a body to hold an electric charge. If the body has a large capacity it will take a large amount of electricity to raise its volt- age. If it has a small capacity it will take only a small amount of electricity to raise its voltage. Thus capacity deals with two things : First, quantity of electricity ; second, voltage. * * * How is capacity measured? Capacity is measured in farads. A body has a capacity of 1 farad if an ampere of current flowing into it for 1 second raises its potential 1 volt. This is such a large unit that it is divided into a million parts and each one of these parts is called a micro- farad. * * * How does capacity operate in a receiver? Instruments that are built to give capacity are called condensers. Con- densers are important in a receiving set. A beginner should fully under- stand capacity as tuning and other methods of employing receivers can- not be successfully accomplished with- out it. * * * How are the condensers made? Condensers are made of plates or sheets of conducting material separated from each other by a non-conductor. Evidently the more and larger sheets used the greater capacity of the con- ductor. The closer together sheets are placed the greater the capacity, as the attraction of the opposite electricites is stronger at shorter distances. The capacity also depends on the kind of non-conductor used between the sheets, as the attraction of the opposite elec- tricites is stronger through some kinds of non-conductors than through others. * * * What amount of electricity will a condenser hold? The amount of electricity a con- denser will hold depends not only on its capacity, but also on the voltage of the charging current, or charging in- strument. There are various kinds of condensers made for various purposes. They are widely used. In using a con- denser be careful not to apply a voltage greater than that for which it is built. If you do a spark will pass through the non-conductor between the plates and ruin the condenser. * * * What is a variable condenser used with? A variable condenser is usually con- nected with an inductance— one of the elements that makes radio possible. The accompanying diagram gives the complete radio circuit of an inductance coil and a variable condenser. Capacity and inductance are the two main ele- ments used in every radio transmitter and receiver. Without them it would be impossible to work. Fifty-two issues for $6.00. Sub. De- partment, Radio World, 1493 Broadway, N. Y. C. Useful Facts for the Beginner Who Wants to Know IN using the vacuum-tube receiver it often happens that the filament flickers or fails to light. In such a case it is a good principle to remove the tubes and clean the ends of the contacts. This is done by either a file or sandpaper. Sometimes the jacks are at fault. When this happens atten- tion should be given the connections of the jack. Before attempting to make changes on the jacks remove all plate-battery connections before making jack adjust- ments to prevent a short circuit, which may result in the burning out of the vacuum-tube filaments. Should both stages of amplification fail to produce, the trouble may be placed at the B batteries. Sometimes defective tubes cause a majority of other troubles.^ It is desirable to test the tubes in various combinations ; that is, try them in each socket. * * * If you are interested in radio and want to receive broadcast concerts don't let lack of technical knowledge deter you. The most marked recent developments of radio have been in making available receiving sets which anybody can operate by following a few simple directions. Operating a complete receiving set, which can be installed in any home, is no more diffi- cult than operating a phonograph. * * * The crystal is the very heart of a radio set. On it depends the entire operation. There are many minerals that may be used for the detector, but up to the present time galena is the best that can be obtained. Do not handle the mineral any more than is necessary, as a coating of oil forms on the surface of the mineral, making the signals weak. Sometimes it will cut down the sensitiveness of the crystal and make the detector in- operative. * * * When employing the detector-ampli- fier unit to a receiver it should be placed as close as possible to the re- ceiver in order to avoid long connec- tions. Always make certain that the battery leading from the storage battery and the B battery are con- nected to their proper terminals, and, also, that the polarities are not reversed. * * * A panel mounting does not allow one to experiment with his hook-up and to show his friends how the circuit actu- ally works. But, to the contrary not- withstanding, a panel-mounted receiver is by far the most attractive in ap- pearance and is often better scientifi- cally if shielded from body effects. Digitized by Google

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RADIO WORLD U Additional Committeemen Named for National Radio Week IT has been a busy week at the headquarters of the Executive Committee of National Radio Week — December 23 to 30 inclusive — the offices of Major J. Andrew White, chairman, 326 Broadway, New York City. Major White and his staff have been kept pretty well occupied answering the many telegrams and letters of inquiry that have begun to pour in from all parts of the country. The interest in this important radio event is increasing every day, and is spread- ing rapidly to all parts of the country. William B. MacNeary, of "The Sunday Call," Newark, New Jersey, has accepted the position of chief of publicity. Elmer E. Bucher, author of several important works on radio, and sales manager of the Radio Corporation of America, " is to be chairman of the Committee on Dealers. Because of the amount of work attending his regular duties, Kendall Banning, editor of "Popular Radio," found it impossible to take on the extra work required of a member of the Executive Committee. His resignation was reluctantly accepted, and Arthur H. Lynch, editor of "Radio Broad- casting," was appointed to fill the vacancy. The following men, all important in the wide-spreading field of radio, have written to the Executive Committee, offering their services to make National Radio Week a genuine success from every angle : Raymond F. Yates, radio editor, "The Mail," New York; Robert S. Wood, radio editor, "The World," New York; E. L. Bragdon, radio editor, "The Globe," New York; William H. Eaton, "Judge," New York; Pierre Boucheron, Radio Cor- poration of America; E. H. Rice, General Electric Company, Schenec- tady, New York. Radioists of Sandusky, Ohio, are planning a program of special radio festivities for the big week. Among the letters received during the week were the following : Robert Curtiss, radio edit or , "Guardsman Magazine," Ashland, Ohio: "I will do all I can for National Radio Week." Arthur G. Shirt, Fall River, Mass., magazine writer and newspaper corre- spondent: "Hooray for National Radio Week ! I am preparing copy about it — its con- ception, its boosters, its aims — for the New England papers for which I write. I will let that be my contribu- tion toward making the week a success." C. White, Cambridge, Mass., con- sulting engineer in radio and elec- tricity, and one of the chief con- tributors to Radio World: "I am greatly in favor of a National Radio Week, and think that the sub- ject of more vigorous cooperation on the part of radio manufacturers for active research and testing as outlined in my article in this issue of Radio World will certainly raise the trade to a higher plane, which is certainly desirable." Nine Microphones Start First Complete Church Service by Radio to Waiting World RADIO listeners and their friends in all parts of - the United States, Canada, and even on the ocean liners crossing the Atlantic, were part of the congregation of St. Thomas' Episcopal Church, Fifth avenue and 53d street, New York City, on Sunday, November S, when the entire service — ritual, sermon and singing — was broadcast by radio. The singing of the choir and congre- gation, the sermon of Dr. Ernest M. Stires, the organ playing of Dr. T. Ter- tius Noble and every word and sound throughout the service was picked up by nine microphones placed in different parts of the church, carried by wire to Newark and there sent broadcast for thousands of miles in all directions. This was the first time a complete church service was sent over the world by radio. It is said that even the clinking of coins dropped in the collection plates was heard. Commenting on this interesting and im- portant radio event, "The Mail," New York, says editorially: "The sermon preached in a Fifth ave- nue church was heard by radio in thirty States, besides Canada, Cuba and Mexico. "This opens possibilities in the religious field similar to the service by the As- sociated Press and syndicates to the newspapers. The smallest congregation can hear sermons every Sunday from able and eloquent preachers, the music of the best organists and the songs of elab- orate choirs. This particular service had the singing conducted by a choir of seventy-five male voices. So well was the sound transmitted that the slightest noise made by people going up the aisle and taking their seats was heard by the radio receivers. "In many villages there are now more churches than the community adequately supports. Denominations are struggling along with small congregations unable to pay their preachers adequate salaries. In the rural districts it is not uncommon for a preacher to have several congregations miles apart and alternate the services in their churches. "With the radio any denomination can have the most elaborate service and costly sermons at slight expense. The home mission boards of the different denomina- tions can arrange radio services. The congregations can gather in the church and maintain their existence without fur- ther contributions than enough to keep the church in repair and heated and put in the radio receiving sets. "Suppose the biblical accounts of the adventures of Moses had stated that the religious services at Mount Sinai were heard in Egypt and Greece and Italy? People of little knowledge and less faith might have called that an impossible miracle." Tube Suspension THE life of radiotjon power-tubes may be prolonged by mounting them in the proper position. Radiotrons No. 13248, type TJV-202 and No. 13247, type UV-203 should be operated in a vertical position, whereas radiotron No. 13246, type UV-204, may be operated in either a vertical or horizontal position. If mounted horizontally, the plates should lie in a vertical plane, with the seal- off tip down. FANS, AMATEURS, DEALERS, BROADCASTERS, MANUFACTURERS, AND THE GENERAL PUBLIC Are Looking Forward to NATIONAL RADIO WEEK DECEMBER 23 TO 30, INCLUSIVE All Interested in Radio Should Help to Make This Event a Smashing Socceea. If you want to know mora about it address: NATIONAL RADIO WEEK EXECUTIVE COMMITTEE MAJOR J. ANDREW WHITE, Chairman 326 BROADWAY NEW YORK Digitized by Google

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12 RADIO WORLD Radio Supplanting Land Lines in Northwest By W ashington R. Service RADIO is slowly supplanting government wire lines in the far reaches of the Yukon. Much of the romance of the Far Northwest is pass- ing with the reeling up of miles of wire stretched by men of the Signal Corps, and kept in operation, despite severe winter storms and intense cold, since long before the days of the gold rush. The first radio station erected in any United States possession to handle commercial business was built in 1903 at St. Michaels,_Alaska. Radio then reached to Nome, replacing many cables and wires. Winter ice across .Norton Sound was constantly carry- ing the hundred-mile cable away and its replacement was expensive, so the stations at St. Michaels and Nome were erected and are still in operation. Later on more stations were erected, chiefly in the interior, until fifteen spark stations were completed. Arc* and Tube* Replace Spark Seta During the past summer, all these stations were modernized by a Signal Corps field detachment under com- mand of Captain C. H. Burkhead, who will remain at Fairbanks all winter to Puzzling Problem of Tuning By Harold Day J B Ammeter of a simple circuit showing and variable < G ~ Schematic the tuning TUNING is a puzzling matter for beginners. It is, however, very simple. It is stated that by varying the size of the coil B, and the condenser, the frequency of ex- change of electrical energy between them — and, hence, the wave length — may be regulated. Study the circuit shown on this page. Assume that the wires, KK, are con- nected to a source of electrical energy, the frequency of which is varied by changing B and C. Vary C, leaving B fixed until a frequency of 1,000,000 cycles, or a wave length of 300 meters, is obtained. Then vary C and D, and it will be found that up to a certain point — and to that point only, the am- meter measuring the current gives a reading. This process is known as tun- ing and the point at which the amme- ter gives reading is known as the "resonant" point. All transmitting and receiving sets operate in the above manner. The difference in the sets be- ing due to the methods used in varying B and C, and C and D. Tuning applies to transmitting sets ; the action being reversed ; and then B and C are varied. High-frequency al- ternating current will be obtained from the wires KK, but the voltage and cur- rent will be in the order of millionths of a volt or ampere. A meter cannot be used. A special device, the detector, is employed, which, with telephone re- ceivers, makes the currents audible. Keep for Reference When Your Set Fails IT should be noted that the scheme of connection in a receiving set is almost similar to that of a transmitting set with one exception: a detector and telephones have been added. The operation has already been explained in special articles published in Radio World. The various wave lengths are obtained by varying the frequency of I o Detector 1 a 'ephones Schematic diagram showing complete crystal receiver. D and B are combined in loose coupler. This is so constructed as to permit of variations of D and B. carry on observations as to the effi- ciency of the newly installed radio equipment. All spark sets were re- placed with arc sets, at important points and with tube transmitters at the smaller stations. To-day there is not an army "spark" in Alaska. The modern equipment, it is estimated, will save about 75 per cent of the old oper- ation costs and improve the transmis- sion materially. Signal Corps radio operators are now working direct from Fairbanks to Nome, a distance of about 540 miles, by radio. The resultant improvement in radio communications has made possible the abandonment of about 200 miles of land wires which had been a tremendous effort and expense to keep in condition, requiring the services of a small army of Signal Corps men, especially in winter time. To-day the army uses a wire from Fairbanks to its cable station at Valdez, but the line from Fairbanks to Fort Egbert was abandoned and the wires west of Hot Springs and Nulato taken down, as well as many lines to the mining cen- ters. A 300-Mile Radio Control To-day an operator at Valdez sends communications over 300 miles of wire lines to Fairbanks and thence by radio to Nome, about 540 miles. Actu- ally he operates a radio arc at Fair- banks from his station 300 miles away, which is very "remote control." In the event of a break in the Signal Corps cable which connects Alaska with the United States proper, the naval radio station at Cordova handles traffic to North Astoria, Oregon, com- pleting the chain to the United States for the army. the circuits and the alternating current obtained from the distant transmitting station which is impressed on the de- tector. The coils, D and B, are conveniently combined in the loose coupler. This instrument is so constructed as to per- mit of ready variation of D and B, and it also permits of the variation of the position of one coil with reference to the other. In the accompanying sketch a condenser, such as C or CI, is shown. These simple facts should be thor- oughly understood by every amateur and fan. Keep this article and the ac- companying diagram for reference. Digitized by Google

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RADIO WORLD 13 Cells May Be Variedby Changes in Connections 6 VoLT- 2o fluM Figure 1. Method employed when connecting up dry cells In eerie*. Drawn by Horace Beers. A KNOWLEDGE of the methods of connecting up dry and storage batteries may prove useful where other sources of current are not available. Standard-size dry cells are used quite extensively for lighting vacuum tubes by amateurs who are not able or willing to hand out the sum of money necessary for a storage battery. The dry cell may be a fairly good substitute for the storage battery, but its use is not advised, except in emergencies, because these cells soon become exhausted and must be replaced by a new set of batteries. The cost of this continual replacement soon mounts up. For the vacuum-tube B battery a number of flashlight batteries may be used as the plate potential for the vacuum tubes. Different uses of elec- tricity require different values of volt- age and amperage. An audio tube generally takes, approximately, one ampere of current to light at a pres- sure of six volts. The plate circuit requires a current that is measured in milliamperes, but at a pressure of twenty or more volts. It must be remembered thaf a dry Erecting Aerial Masts A SIMPLE way of raising aerial *■ * masts to any considerable height is to plant a short staff about one-third the length of the main mast, close to its base and raise the shorter mast by means of tackle. Guy ropes should be slung from the mast about two-thirds the way up, to permit guiding. It is usual to make the aerial of more than two spans of wire, so that a greater conducting surface will be represented. For stations up to 1 kilowatt, size and aerials should have at least 6 wires spaced not less than 2 feet apart or more than 3 feet. It has been found that nothing is gained by placing the separate spans closer than 2 feet. For fairly large aerials, 3 feet is very good spacing. Fifty-two issues for $6.00. Sub. De- partment, Radio World, 1493 Broadway, N. Y. C. By Horace Beers cell has a voltage of lyi volts when new, and should show about 25 to 30 amperes. The storage cell, after being in use for a short time, registers about 2 volts, but their short-circuit ampere reading should never be considered, as it is ruinous to the cell in making the test. Such cells are rated in "ampere hours." This term may be taken literally, as an ampere hour means the flow of one ampere for a period of one hour. Usually about 8 amperes ca"n be drawn, as a maximum amount, from a 60 ampere .hour storage battery. For different uses cells may be con- nected in series, or parallel, or in com- bination of the two. When we con- nect in series we increase the voltage. When we connect in parallel we in- crease the amperage. Suppose we have 4 dry cells and wish to operate some pieces of apparatus that require 6 volts with- out a large consumption ' of current. By connecting the cells in series the total voltage is the sum of the voltages of the individual cells. In this case the cells are \y2 volts eactj; so 4 in series would give us 6 volts. By series we mean that the center post of one cell is connected to the side post of the other. If a greater amount of current is needed we can connect our cells in what is known as series-parallel, as Figure 2. Method employed when connecting- up two banks of dry cells in series parallel. Drawn by Horace Beers. shown in Figure 2. This consists of connecting 2 series sets of four in parallel ; that is, by connecting the 2 positives and, likewise, the 2 negative end-poles of the 2 series. Take the leads off as shown. This connection doubles the amperage, while the volt- age remains the same. Further in- crease in amperage may be obtained by adding more banks of cells to the system. This same rule applies to the storage battery; but, as the batteries register only 2 volts each — three when con- nected in series — it would give the necessary 6 volts. These simple facts regarding bat- teries should be remembered by every radioist dabbling with batter- ies. A storage battery having 3 cells would register 6 volts; one with 2 cells, 4 volts, and so on. Never con- nect or short circuit a cell. By this we mean, never place a wire or other piece of metal across the negative or positiveof a cell. It will completely ruin it and you will be wondering why the battery will not produce current. (Cartoon by Lawrence B. Hinckley) A RADIO BUG'S IDEA OF PARADISE Radio Angel: "Help yourself, son. If you don't find all you want this trip, come again T> Digitized by Google

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14 RADIO WORLD Radiograms * Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengtha for the Busy Reader. RADIO U playing an important part in the work of mapping Northwest Canada. By tuning in and getting time signals from a known distant point and comparing it with the time at a designated place the map-makers can easily ascertain distances and directions. * * * Scientists have discovered that the aurora has a decided effect upon radio. Apparatus affected by the aurora could receive, but not transmit, signals while the influence lasted. * * * SAM is the call of a new radio-compass station at Hallo on The Skagerrak, Sweden, which was opened for general service on November 1. The new station, which is operated through Goteborg, SAB, will determine the true bearing of vessels calling within 150 miles on a 600-meter wave length. The charge for a bearing is placed at five kronor, about $1.34. * * * The Radio Corporation of America has announced a radio- letter service to London and Germany at a rate slightly higher than postage. The rate is six cents per word. Messages filed any day in the week up to Saturday marked "Radio-letter" are transmitted to London or Germany for delivery on the following Monday morning. * * * The United States Signal Corps at Washington, D. G, con- tinues to save money through the transmission of official messages by radio instead of by land wires. In September a total of 239,826 words were handled, with a saving for the month of $2,668 over the cost at commercial rates. * * * Radio wins a race! "Radio," ridden by L McDermott, won the Latonia Cup at Louisville, Kentucky, with an added purse of $7,500, over a distance of two miles and a quarter in 3:49 flat. * * * Recent modifications of the rigid laws governing the installa- tion of radiotelephone and telegraph stations have made possible the installation of radio-broadcasting, according to Vice-Consul Edwin B. Montgomery, of Montevideo. Applications are now pending which, if granted, should mean the opening of a splendid market for radiotelephone receiving apparatus in Uruguay. » * * Fred Stone, president of the National Vaudeville Artists, was the guest of honor at a luncheon at the William Penn Hotel, Pitts- burgh, given by prominent citizens. All the speeches made were sent out by radio. Among the speakers were: Harry Davis, Senator John P. Harris, president of the Theatre Managers' Asso- ciation of Pittsburgh; Senator George Wharton Pepper, Senator David Aiken Reed and Mayor W. A. Magee. * » » Gambia, the British colony in West Africa, has installed radio telephone and telegraph stations at Bathurst and McCarthy Island, 176 miles apart. The new stations are in daily use, giving in- stantaneous communication between the two centers. The colony has no organized wire telegraph or telephone system, and the radio stations already have proven of great value. » * * Members of the United State* Army, organized reserves and National Guard in San Francisco will have the opportunity to buy some of the 10,000 army receiving sets at $7.50 each. These sets were declared surplus stock, and cost $1,000,000. Buyers are limited to military men only. * * * The call letters for the station recently opened at Havana, Cuba, are PWX. * • * Great Britain has given the Wireless Society of Manchester permission to erect a special transmitting station for the purpose of attempting to bridge the Atlantic from the east to the west with one kilowatt of power. The extraordinary license issued for this station specifies that no more than this amount of power shall be used and that the apparatus shall utilize continuous waves. In Great Britain the restrictions which have always been maintained on amateur stations even specified what kind of aerial should be used, and placed limitations upon its size. In the license given to the Manchester society this rigid rule has also been modified, and permission granted for the erection of a more efficient type of aerial tor the purpose in view. * * * The steamer "Matsonia, equipped with a 1,000-watt General Electric Company radio set, talked through its telephone every morning from September 12 until September 25, the day before she arrived in San Francisco from Honolulu, with the radio station at Apia, Samoa. The last conversation was at 8:30 o'clock in the morning. At that time the "Matsonia" was 4,050 miles from Apia. On this voyage the "Matsonia" was in radiophone com- munication the entire trip with either the San Francisco office of the Radio Corporation of America, KTH, or the Hawaiian station, KHK. All the ship's radio work was done on a wave length of 550 meters. * * * Experiments are being made in Belgium for rapid reception of messages in script by a photographic process combined with radio. * * * Radio development in Czechoslovakia has not yet passed the stage of infancy, according to dispatches to the Department of Commence from Consul Winans, Prague. He states, however, that the government has already taken an active interest in radio development, and in view of a more extensive and popu- lar acceptance of this form of communication at home has sent a special commission of experts to study the progress made In other countries. Whether a sending station for radio messages will be established in Czechoslovakia will depend upon the find- ings of this commission. Even when finally introduced, how- ever, the local industry cannot be expected to attain the state of development reached in the United States. It is stated by the Ministry of Posts and Telegraphs that all messages sent by radio will be subject to strict control by the Government ; not every person will be permitted to own a receiving or send- ing apparatus. High duty will be assessed on radio outfits and supplies of foreign make, and each radio set, whether of do- mestic or foreign manufacture, will have to be registered at the Ministry of Posts and Telegraphs. Many local factories are said to be interested in the future of radio telephony and to be awaiting a favorable moment for producing the necessary requirements of the industry. * * * Over 5,000 words on the election results in New York and other parts' of the East were sent to California by radio on election night, the wire service having been seriously inter- rupted by a sleet storm in the Rocky Mountains. The station of the Radio Corporation of America at Rocky Point, which is ordinarily used for sending radio messages to Europe, sent returns to the radio station at Bolinas, near San_ Francisco, which is ordinarily used only for communication with the Far East. Western returns also were received by radio from Bolinas. * * * Beginning November 26, the radio audiences will hear the first of m series of thirteen Sunday afternoon popular concerts by the City Symphony Orchestra, which will be broadcast by the Westinghouse-Radio Corporation station, WJZ, at New- ark. These concerts will be held at the Manhattan Opera House, New York City, and will be conveyed to WJZ by a spe- cial Western Union wire. The programs will consist of gems from the lighter classics, together with shorter symphonic poems. Young soloists of real talent and distinction will be heard at each performance. The City Symphony Orchestra, which is maintained by the Musical Society of the City of New York, consists of 83 players carefully selected for their musical talent and symphonic experience. The conductor, Mr. Dirk Foch, a native of Holland and a composer of distinction, has had a successful career as a conductor of symphony concerts and opera in Amsterdam, The Hague, Stockholm, Gothenburg, and other European cities. * * * "Aida," Verdi's great opera, was broadcast from the Kings- bridge Armory, New York City, on Saturday evening, Novem- ber 11. The performance — which marked a new era in radio and made history for this wonderful science — was given by artists and the orchestra of the Metropolitan Opera House, New York City, undoubtedly the greatest organization of its kind in the world. Sent out by the powerful station, WEAF, it was heard over a range of a thousand miles. Send Radio World Your Best Suggestions for National Radio Week Digitized* by Google

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RADIO WORLD 15 Radio and the Woman Crystal D. Tector AMONG the many letters that I have received since the movement for National Radio Week started but one con- tains a negative note. Now, I wouldn't mention it — at least, first of all the communications that have come to me — if I did not believe that every objection contains some possible suggestion for good. I once belonged to a club, and one of the members seemed to take particular pains objecting to every- thing— everything I She called herself the "natural born ob- jector." We other women almost hated to start anything new, knowing that this particular member would never agree. We have all encountered such a person. But they seldom do as much harm as good — and it is generally good business to have one on a committee. • * * Well, the correspondent I started out to write about is a Miss Jane Drophie of Chicago. Her objection is summed up in one sentence which I cull from her letter : "Won't the men take all the glory of National Week and won't they get on all the committees and have everything their own way?" • * * I imagine that Miss Drophie hasn't advanced much in up-to- date matters pertaining to women's place in the world — even if she does live in Chicago. My reply to her, and to any other woman who feels that we women are going to take a back scat during National Radio Week, is this: 'If such a thing conies to pass, it will be the fault of the women and the women only I And I think that I am sufficiently acquainted with my sex to make the statement that we will have just as much to say as the men — and, whisper, perhaps a little morel • * * Let me tell you a few of the preparations that the radio women of the charming suburban town — just a pleasant ride from New York — where Friend Husband and I have the dearest little home in all the world, are making for National Radio Week. • * * First we organized the Women's National Radio Week Execu- tive Committee. We could have had fifty members, but at the first general meeting we all decided that a small workable committee with absolute powers would be the most satisfac- tory. So a committee of nine was decided on. The chairman of our first meeting appointed four, and the remaining five were chosen by ballot — that is, everyone at the meeting was asked to cast a ballot for her choice and the five polling the highest votes were declared elected. • * • This committee has the power to appoint subsidiary com- mittees on publicity, dealers, shop-window decorations, enter- tainment, and any other phase of radio that may seem neces- sary. We consider that one of our most important committees is the Committee on Church Program and Entertainment, for no little interest in radio is centered in the churches in my town ; and, this winter, we look to some wonderful evenings, as not a few of the churches have splendid sets. However, this par- ticular committee will endeavor to have special radio nights and afternoons in as many churches as possible during National Radio Week— jolly entertainments and socials where people will meet and get acquainted, and, we all hope, become radio fans. • * • Another committee of importance will work among what we call "radio strangers." The members of this committee will visit those who have taken no interest in radio, and try to bring them to the church entertainments, the affairs at different homes, the radio stores where the general broadcasting may be heard, and to advise the most practical reading in order to learn radio. You may imagine that such a committee has a good deal to do; but from the reports I have received, our committee is doing wonders. I can safely say that, during the past ten days, we have made radio converts at the rate of a dozen a day. I do not mean people who promise to take an interest and then bid you a cheerless farewell ; but people who have become so interested that they have not onlv thanked you but have asked you to come again. • * • We also find that one of our busiest committees is going to be the one that will advise shopmen how to decorate their windows and make their stores attractive. As we all know, the average radio dealer, or electrical merchant, is a pretty busy man in the first place, and, in the second, his wares do not make very attractive window and inside displays. N'ow her • is where we women can do yoemcn's service. I am certain that as National Radio Week approaches few radio dealers wilt object if one or more pojite, well-intentioned women approach them and ask if they may show Mr. Dealer or Mr. Shopkeeper how to present his goods in a way that will not only make them decorative but attractive to the prospective buyer. * • * Then, too, we women can do much to give the many social affairs that are bound to make National Radio Week sparkle the very eclat they will need. We will be of great service in getting up programs for the younger set — meetings and dances with radio as the foundation and the background. Why, already, I have had over a score of hidden requests for invita- tions to several affairs that I have announced — and I only wish that my home were larger — as large, indeed, as a barn or as the Pennsylvania railroad station in New York City— and I would just issue, right here, in the columns of Radio World, a general invitation to all to be present. "The more the merrier," say I. » * ♦ I think that I have given my women readers a few hints here. One clever hustling woman in any town can easily start this movement going. It will be surprising how quickly it will take hold. For radio is new, and we Americans are ever on the alert for something new. It won't be long before the spirit of the thing will spread, and, I am bold enough to make the assertion, in any red-blooded American town, doing some- thing for National Radio Week, or being on a National Radio Week committee, will be very much the vogue. * » • And, let me tell you in advance, there is to be some wonder- ful broadcasting this winter. We are to hear grand opera bv the artists and the orchestras of the Metropolitan Opera House, New York, the very finest thing of its kind in all the world. We are to have the rendition of symphony orchestras that comprise the highest-paid musicians. We are to have the news of every great event. We are to hear eminent singers and instrumentalists — and we will have plays produced that, otherwise, we might never have a chance to see or hear. So, you see, radio is working for a wonderful future, and National Radio Week promises, more than anything else, to give us a glimpse of that future. * * * I can't help being so enthusiastic because I so fully believe in it. And I want to help you — all of you women who are inter- ested in radio! And the editors of Radio Would will help me to help you by devoting these columns to you every week. Boys! This Tells You How to Use an Antenna with Your Kite There are time* when bojr» like to expeiim-nt with something more than the In th. .crom- two of to rmic a kite. It la thrlr Intent on to utilize thia kite by attaching a wire to It la order to experiment with al- titudes hi(her than thoae o( the average root aerial Their receiver is of the crys- tal type, and when the kite la aloft some thousand feet, unusual results may he ob- tained This is an experi- ment to find out whrthrr the height of an aerial haa any more or leas effect on the volume or distance of signals. Instead of Hying the kite with a string, a light wire ia used (C. Ka.lrl a Herbert)

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16 RADIO WORLD Another Busy Radio Week s (C. International News Reel) (Above) Every man hi* own aerial 1 This is a possibility, according to Collins Pan, a radio fan of Minneapolis, Minnesota. Mr. Penz has a small set in bis home. One day, during a testing out while it was hooked up, he noticed that he could hear a broadcast concert while he kept' his fingers on the slider of the tuning coil, as shown in the photograph; but when he removed his fingers, the music was not audible. His body served as a natural aerial. Mr. Penz made his by winding two coils of wire — one large and one small — around an ordinary megaphone. This gave him a primary and a secondary winding, making it (Below) The pensive man in this photograph is Alfredo Zayas, President of the Republic of Cuba, in his private office just after talking into a microphone. It was the occasion of the broadcasting of the Cuban president's address to the American people, which proved that the span between the two republics may be covered by radio in the fraction of a second. Radio develop- ment in Cuba is having a great boom— particularly since the broadcasting of the World's Series high-power stations are to be erected in Havana. General interest in radio matters is thoroughly active and Cuba is a hearty Digitized by Google

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RADIO WORLD 17 Is Seen by the Camera Men (Left) MIm Nellie D. Stevens !• the first person to re- ceive a photograph trans- mitted by Radio. Here Is Miss Stevens decoding a "ra- dio-photo" of Mies Virginia Valll. Universal Film star, which was sent from Lon- don to New York by radio. On the artisfs drawing board are two portraits of Miss Virginia Valll. The picture on tho left of the board Is a copy of the por- trait transmitted through tho air; on tho right Is tho result of Mlas Stevens's de- coding. She is now engaged In perfecting a method of transmitting ftnger-prinU by radio, in tho United States. To the left Is a facsimile of • coded portrait as re- ceived by Carl Laammla. president of the Universal Film Manufacturing Com- pany. Sending photographs by radio is becoming a sim- ple matter. It Is possible to radio photographs over a groat distance, one having been successfully sent from Italy to the United States. (C. Wide World Photos) (Left) The motorcycle is Nail Cochran, of Oak- land, California. 1* shown bora tuning m on the radio station of The Tribune** of that city. Mr. Cochran drove the radio-oqulpped motorcar which trapped the "ban- dit" ha tho recent "ban- dit chase" held in Us State. (Above) This picture / radio set made by boys. To be sura, they had the guld- stmctar. This par- ticular set kt for long- distance recaption. Radio World would be pleased la aee photo- graphs of sets made other boys, and m- vttee them to sand In such ptctmaa with a view of having them published for tho let. f« u . | * a ad- l rhapsths tut fa- a bread, •a. late • atleal- 4c* the •later. It I a* awst wees of kt radio ■ - abb area the •a ,kb> (C. Kadel & Herbert) (Above) The football season baa been considerably augmented by radio. Broadcasting the big games la vary much in vogue. As in the case of tho World's Series, these moat interesting ath- letic events, so important to lovers of American sports, wore received, play by play, in thousands of homes all over the country. The photograph Illustrate* the receiving and smiling station at Fordham University. New York, assigned primarily for tho exchange of football scores and relay work between the various collages. This station operate* on SSS watts and nam from two to four U-V XH tubes. Edward J. Hefesa, one of the students of Fordham. is shown kt the photo- graph broadcasting a football game taking place on the coOege r. (C. Kadcl ft Herbert) (Above) Mr. Sheu S. Man, a graduate of the Hong Kong University, testing out the static characteristics of vacuum tubes at Columbia University, New York. Not a few young Chinese have come to the United States to learn tho mysteries of Few user* of radio realize how kt involved In the V of vacuum tubes. (C. Central News Photo bervtce) (Above) Arthur Alexander, the American tenor, announces that his avocation la radio. This successful young singer is one of the most ardent ians in the country and says that he wouldn't care If he were a radio operator aboard an ocean liner.

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18 RADIO WORLD Radio- Wire Tables By Frederick J. Rumford, E.E., R.E. No. 1 — Enameled Magnet Wire Showing the Number of Feet of Magnet Wire in a Pound and Fractions of a Pound APPENDED is the first of a series of five tables which the radio amateur will find useful for many purposes. The succeeding tables — "Single Cotton-Covered Wire," "Double Cotton-Covered Wire," "Single Silk-Covered Wire" and "Double Silk-Covered Wire" — will be published in early numbers of Radio World. Approximate Diameter turns per yAib. lib. No. in mils. square inch ^lb. 20 .0337 , 885 40 80 160 320 320 21 .0302 1,126 43 86 172 258 404 22 .0269 M0) 63 126 252 378 509 23 .0241 1,736 80 160 320 480 642 24 .0215 2,160 101 202 404 606 810 25 .0192 2,770 127 254 508 762 1,019 26 .0171 3,460 160 320 640 960 1,286 27 .0153 4,270 201 402 804 1,206 1,620 28 .0136 5,400 255 510 1,020 1,530 2,042 29 .0122 7,900 321 642 1,284 1,926 2,570 30 .0109 10,000 405 810 1,620 2,430 3,240 31 .0097 12,620 510 1,020 2,040 3,060 4,082 32 .0087 16,020 641 1,282 2,564 3346 5,132 33 .0077 20,400 25,200 805 1,610 3,220 4,830 6,445 34 .0069 1,010 2,020 4,040 5,096 6,060 8,093 35 .0062 31,900 1,274 2,548 7,644 10,197 36 .0055 40,000 1,601 3,202 6,404 9,606 12,813 37 .0049 .0044 51,600 2,013 4,026 8,052 12,078 16,110 38 65,700 2,534 5,068 10,136 12,756 15,204 20,274 39 .0039 81,600 3,189 4,013 6378 19,114 25,519 40 .0035 14,000 8,026 16,052 24,078 32,107 The figures for the sufficient to cause any harm, nate decimals. y2- and 54-pound wires are a few fractions off, but not The computations were made in this way in order to elimi- Uncle Sam Turns Out Two New Amplifiers One Is an Electron-Tube Amplifier Using 60-Cycle Alternating Current to Supply Power for Fila- ments and Plates. The Other a Radio-Fre- quency Device Using the Trans- former Coupling Method AN amplifier which has the advantages of low first-cost and cheapness of oper- ation, besides doing away with the incon- venience of the storage battery and the B battery, was developed recently at the Bu- reau of Standards, Washington, D. C. A crystal detector and 5 stages of ampli- fication, 3 stages of radio-frequency ampli- fication and 2 stages of audio-frequency amplification are used. The first arrange- ment tried consisted of 1 radio-frequency stage of amplification, tube detector, and 1 stage of audio-frequency amplification. The filaments of the 3 tubes were lighted by 6 volts supplied by a stepdown transformer, the primary of which was connected to 110- volt, 60-cycle power mains. It has been found that either air-core, or iron-core, transformers may be used for coupling the output of one tube to the input of the next tube. The air-core transformer gives more amplification per stage, but is responsive to only a narrow band of fre- quencies owing to the low effective resist- ance of the windings. The iron-core type, while not giving as much per stage, allows amplification over a much broader band of frequencies. A special type of air-core transformer which will respond to signals on wave lengths from 600 to 1,000 meters has also been developed. The coils of the trans- former were wound in the form of a flat doughnut, the wire being wound in a manner similar to that of the open, or basket, type of coil winding. They are wound continuously from the inside to the outside. Two of the coils constitute an air- core transformer, one coil being connected in the plate circuit of one tube and the other being connected to the grid cricuit of the succeeding tube. It is found that when the primary and secondary transformers are placed about yZ inch apart the transformer gives best amplification at 600 meters, and when the coils are placed close together the amplifier operates best at 1,000 meters. This is due to the increase of the capacity between the coils when placed adjacent. An amplifier has three stages of radio-fre- quency, two stages of audio-frequency amplification, and a detector tube. . Scientific Paper No. 449 of the Bureau of Standards, Department of Commerce, describes the construction of a new radio- frequency amplifier which uses the trans- former coupling method. Radio- frequency amplification consists in the amplification of the received radio-frequency current before it is detected. By the use of radio-fre- quency amplification and a coil antenna a signal which is very feeble can be made loud enough to be heard throughout a large room. Three methods are described by which the electron tubes may be coupled together so as to give radio-frequency amplification — resistance coupling, tuned-plate coupling, and transformer coupling — the latter having been found most satisfactory. In order to operate well the radio-fre- quency amplifier should have a transformer designed so that it will have small capacities in the windings as well as between the windings, and in connecting the transformer in the amplifier circuit care must be taken to have all connecting leads as short as possible. The alternating current was rectified by means of a gas-filled, two-element rectifier tube, called a "Tungar" tube; but it was found that the residual hum was greater than when the alternating current was not rectified. When an electron tube is used as a detector there is impressed on both the plate and filament a 60-cycle alternating current voltage, which, although small, becomes objectionable when amplified by one or two stages of audio-frequency amplification. When, however, a crystal detector is used instead of an electron tube detector it has been found that the 60-cycle hum is practically eleminatcd and that the crystal gives as good rectification as the tube detector. After much experimental work a circuit consisting of three stages of radio-frequency amplification, galena crystal detector, two stages of_ audio-frequency amplification, loud-speaking reproducer, and the necessary power transformer and rectification circuits were found which allowed the reception of music, and telegraphic signals without too much interference from the humming noise just mentioned. Mr. Miller's Circuit from Another Angle EDITOR, Radio World: In refer- ence to your request for informa- tion relative to the new circuit for ex- perimenters in Radio World, No. 30, dated October 21, the writer notes that Mr. W. Miller, Southern Methodist Uni- versity, Dallas, Texas, claims to have worked out this circuit. Possibly he did. However, the writer, also Mr. j. Fisher, of this city, have been using this circuit for about one year, not as Mr. Miller de- scribes it, however, which in the writer's estimation, is a very cloudy method. In the place of the D-L 50-coil, a variometer should be used. This gives tuning over the entire wave length unless one is look- ing for Japanese or Chinese stations on the Atlantic Coast. In addition to this, a .00025 mfd., should be discarded for a variable condenser. Then by using one stage of audio frequency in connec- tion with this circuit, one is able to tune in sharply and receive stations anywhere from 600 to 1,000 miles.— F. D. Tyndall, 836 Kingston avenue, Oakland, California. RADIO GOODS AS GIFTS Be sure to be represented in "Holiday Radio Gifts Number," out December 9, Copy for this issue accepted up to Novem- ber 29, Radio World, 149 Broadway, New York. Subscribe for RADIO WORLD. $6.00 a year, $3.00 six months, $1.50 three months. Digitized by Google

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RADIO WORLD 19 Help to Squelch QRM Suggestion that "The Rochester Plan" Be Put General Force to Prevent Conflict Between the Novice Listener and the Radio Amateur in AS a result of experience through the past year of broadcasting, we have a definite program to recommend for ama- teur consideration. There have been many unjustified complaints against amateur QRM; and, of course, where amateurs in cities have hogged the air all evening there have been justifiable complaints. Most of us have realized, says Kenneth B. Warner, editor of "QST," November, that broad- casting was capable of becoming a power- ful force for good in our country, of tre- mendous social, economic and educational value, and have known that meant the pass- ing of the old days when we could pound brass from supper-time on and the usher- ing in of a new era when the air had to be shared. As we have pointed out pre- viously, many of us have gone so far in the business of sharing that we have almost been afraid to operate at any time, and amateur radio has suffered for the lack of a definite plan. On the other hand there are uniformed novice listeners who object to amateur transmission at any hour of night, and again the need for a recognized scheme has been shown. This we now offer. Broadcasting is admittedly an institution of the early evening hours. That is the time that quiet air should prevail, when the greatest good can be done for the greatest number. When should we open up our sta- tions for transmission ? Our board has con- sidered that question and has decided upon 10.30 p. m. as the proper time. We're re- gretfully obliged to conclude, fellows, that the time is here when we should voluntar- ily keep our transmitters silent during the early evening hours if their operation inter- feres with listening. This means that in all congested communities amateur stations should be quiet between the hours of 7 p. m. and 10.30 p. m. This is no new thing for most of us— we've been doing it already— but it makes it a recognized principle of amateur work. We urge our members and clubs to get together with the listening-in element in their community and have an understanding on the subject. Acceptance of this plan on the part of the amateurs means that they recognize the rights of the listeners to hear their concerts undisturbed, and that they will keep quiet between these hours. Ac- ceptance of this plan by the novice listeners means that they recognize the rights of us amateurs to transmit and carry on our use- ful work and that they will not complain against the "meaningless buzzes" when the lid goes off at 10.30. TWs plan was pro- posed at a meeting of all radio people in Rochester, recently, and was adopted as a solution of the local difficulty. We may well call it "the Rochester Plan." Whenever a community gets together and agrees upon such a plan, we feel that it should become as law and that the mere possession of a transmitting license should not entitle an amateur to go contrary to the sentiment ef all his fellows. It is our view that such operation, unless justified by an emergency or official tests, would constitute deliberate and malicious interference within the meaning of the federal radio law, and we believe the Department of Commerce will agree w^th us. On the other hand, in localities where this plan is adopted and quiet air is maintained between 7 and 10.30 p. m., we will expect amateur transmission to proceed without complaint after 10.30, and the A.R.R.L. will protect with every resource at its command the right of any of its members to so transmit if unjustly ac- cused while legally operating in such a community. Now we have a working plan. Let us adopt it, fellow amateurs. This puts an important duty of self -policing on the shoulders of our affiliated clubs and we are depending upon them to handle the job. When this plan is adopted it must be re- spected, religiously, and this means that un- licensed and improperly adjusted stations must be hunted down and turned in. In bygone days such a station bothered no- one but its neighborhood amateurs, and if they could put up with it there was no harm done; but today such a station will bring discredit upon all of amateur radio and must not be permitted to exist We would suggest that clubs establish committees to help local amateurs and render assistance when needed to get a station properly ad- justed, but if the operator persists in operat- ing illegally after being warned he should be turned in to the inspector without mercy — we have too much at stake. Other folks are watching us too; and while we think about it, we want to tip off everybody to get their station and operator licenses re- newed promptly upon expiration. What about local work, which used to occur in the early hours of the evening? Honestly, we don't know, and it will be up to the amateurs of each club to decide for themselves how they will divide their hours. The time after 10.30 is going , to be very precious and, solely because it is not as im- portant as DX work, we are afraid local work will have to be got over with by the time 7 o'clock rolls around. Low-powered battery-operated CW sets of course can be used for local work all evening long and not cause a particle of QRM for the broad- casting fan next door, but most of the lads who do local work have a far different kind of equipment 1 Our transmitters must improve. There will be too many of us with traffic to move at 10.30 and too many listeners with dumb- bell tuners for us to continue much longer with the cycle-consuming spark of pre-war days. For the very efficiency of our traffic moving the selfish spark will have to yield to the valve set. We hasten to say, though, that there are selfish CW sets too, and we are just as much agin a bum CW without rectifiers and filters as we are against the ordinary spark, and for exactly the same reason— it takes up too big a place in the air, its wave is too broad. We cannot be pushed into an adoption of CW versus spark against our will, but left to our own devices we believe it is evident to any thinking amateur that the quiet efficiency of the little bottles is just the thing we need— filtered DC, CW ransmitters. Now let's get busy on our self-imposed 10.30 lid. Remember that the League does not feel that it can back a member who runs loco in a congested locality and smears a whole county with QRM from the minute his supper is down, but that it will safe-guard the interests of its law-abiding members in communities where the Rochester Plan is adopted and respected. One thing more. Noise this about a bit Let it be known that we amateurs have de- cided among ourselves to preserve some quiet hours, out of consideration for the broadcast listeners. Spread a little honest propaganda in your local newspapers. MARaWox Unless receiving set is complete without i£- THE Magnavox Company have been pioneers in the development of devices for sound amplification. When you purchase a Magna- vox Radio or Magnavox Power Amplifier you possess an instru- ment of the very highest quality and efficiency. Type R-2 Magnavox Radio with 18-inch Horn THIS instrument is in- tended for those who wish the utmost in ampli- fying power; for large audiences, dance halls, &c, but requires only .6 of an ampere for the field. Price, $85.00 Type R-3 Magnavox Radio with 14-inch Horn THE same in principle and construction throughout as Type R-2, and is ideal for use in homes, offices, amateur sta- tions, etc. Price, $45.00 3-Sub Magnavox Power Amplifier Model C I NSURES getting the largest 1 possible power input for the Magnavox Radio. Can be used with any "B" battery voltage which the power tube may re- quire for best amplification. AC-2-C, Z-Sui. $80.00 AC-VC, 3-Staie 110.00 Magnavox product* may b« had of good dealers everywhere. The Magnavox Co. Oakland, California N. Y. Offkal J70 Savants Ava. xvadio' brings it Ji/AGJVAVOX tern Digitized by Google

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20 RADIO WORLD Latest Radio Patents Dr. Alfred N. Goldsmith Invents Device to Improve Tone Transmission No. 1,432,454. Patented, October 17, »ZZ. Patentee! Alfred Norton Goldsmith, New York, N. Y. DR. ALFRED N. GOLDSMITH, secre- tary of the Institute of Radio Engineers and chief of radio activities at the College of the City of New York, has been granted letters patent on an apparatus to improve the tone transmission from a sustained wave- generator. Since sustained wave-transmitters produce signals consisting of constant-amplitude radio- frequency current, such signals are in- audible, or practically so in a receiving sys- tem having the usual rectifying detector, such as a crystal or vacuum tube. Notwith- standing this fact, transmitters on ship board which may be called upon for distress signals, are compelled by law to be capable of radiating a signal wave of such character that it is possible of reception and detection in a simple detector of a receiving set. It is accordingly highly desirable, and even necessary, to provide a method of control- ling and modifying the sustained wave-radia- tion of an arc, alternator, oscillating vacuum tube, or other sustained wave-transmitter so Figure 1 is a diagrammatic representation of circuits and apparatus for carrying out the in- vention of Dr. Alfred N. Goldsmith. Figure 2 is a detail side view of the rotator of the modulator. that periodically modulated radiation is cap- able of being produced; that is, the am- plitude of the radiation should be periodically varied at audio-frequency. This method of modulation may be advan- tageously applied to apparatus for transmit- ting from a sustained wave generator, is the belief of Dr. Goldsmith. Will Locate Moving Bodies by Radio 7 ^f* fi*"1 ^ t-,1 1 r^m ttJ — r1 m | Wiring diagram showing the arrangements of the circuits of Mr. Conners's invention at two transmitting stations and a control station. No. 1.433,«7t. Patented, October 24, 1122. Patentee: Walter W. Corners, Elizabeth, New Jersey THE invention of Walter W. Conners is an apparatus for determining the actual location and actual movement of bodies. It will find, also, the actual location of a transmitting or a receiving station. The altitude of a receiving station may be ascer- tained and represented in miniature. The location and movement of anything move- able equipped with a receiving station may be indicated. The distance of a receiving station from a transmitting station, as well as its geo- graphical location, may be ascertained by this invention. It will indicate and trace on a map, or chart carried by a moving body, the movements of that body and give its location at any time. This is one of the most important radio inventions of the day. * *. * Spark-Gap Improvement No. 1,4ZB,SS4. Patented, September 12, 1(22. Pat- entee: Leslie O. Parker, Swissville, Pennsylvania. MY invention," says Mr. Parker in his patent papers, "relates to wireless apparatus and, particularly, to that class of apprentices which employs two relatively movable electrodes, one of which is sta- tionary and the other a rotable toothed disk, the teeth of the latter moving past the tip of the stationary electrode to make and break a circuit across a gap located between. "In order that the make and break shall occur at the peak of the voltage Figure 1 is a longitudinal sectional view of a high-frequency wireless generator equipped with a spark-gap structure embodying this invention, and Figure 2 is detailed view of parts of the generator and the mounting for the stationary electrode. wave, it is necessary that the electrodes shall be relatively adjustable to permit them to be correctly positioned with re- lation to each other. This adjustment is usually effected by moving the normally stationary electrode circumferentially of the rotable electrode. "My invention is to provide a spark- gap structure in which the normally stationary electrode shall be supported by, and insulated from, the end bracket of an alternator in a simple and inex- pensive manner, and so arranged that it is readily adjustable on its support and accessible for inspection and repairs. East Harlem Radio Club Elects Officers THE Radio Club of East Harlem, New York City, organized September 20, 1922, has elected the following officers: Harold Itzel, president; John N. Itzel, secretary, and John D. McEvily, treasurer. The club meets every Wednesday at the Federation Settlement, 127 East 106th Street, New York City, at 8 o'clock. Any radio fan who desires to become affiliated with this organization may do so by writing to the Radio Club of East Harlem, Harold Itzel, president, 175 East 111th Street, New York City, for particulars. WE NEED RADIO WORLD, dated April 22 and August 5. If you have copies you (*on*t re- quire, mail to this office and current issues will .. ..... f__ »»t«~ WORLD, 1493 m"">-i nitiii iu tills uinuc an>i turn l^y^Y^C RADI°

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RADIO WORLD 21 ALADDIN ELECTRIC COMPANY, INC COMPLETE RADIO SETS WRITE FOR PRICES. 65 Weil Broadway, Now York City d Is Dialer* tor RADIO STORES CORP. VARIABLE CONDENSERS- PLUGS— RESISTANCE UNITS. ETC II w Ssalsr kw'l mm. addrftfts 0.*. 0. Variometer! with dial, $2.38 Variocouplers with dial, $1.88 Post Paid Money Back 1/ not Satitfactory OSLAND, INC. 122 FIFTH AV. NEW YORK welcome: com in and hear TBI CORACO RADIO CONCERT DaJly. I A. M. M • P. M. Ktk f »*• *• 42*4 SI.. M»t U Aa)it«r«ftai ThMlr* Tba Caf.ro Bui»r tUdi.ipbon. U ta» UM Sal irwM impruf.mrtit In rm.fl.. It has oa ■»* saanaftlMW — do Installauoau aipassa — 1b ** atmpla ts sperftte u ft phaooarftpk. U rau saans* SbR) writ, far lull Infarinftttun. THE CORACO COMPANY, INC. Ill WM 42ad Strsst »•» v»** RADIO MAILING LISTS IITI l«ull R.dl. Daalara. Cnitad 1114 Radio Man'ul.ctutar.. .f* |l«t. }•■•• 1134 lUJlo Hgpflj Jobbers per list. 11.11 15T Hadle ■aiiufaclurerft of ftom- plete sals per Jtat. 4.S4 1(4 Radii Olatlooe per U «. 14444 kMSt AmftU-uri and Mm «,n J IU,I., «>.»i. I.r ». 1.50 N»U, ^tjvwrrlt^tcn ^ftn^^r-^ ^^Jf ■ TR.ll»ltTlU|-| I A It AUI)KF>MJ.G CO. IMS STREET CMICA80. ILl jA microstat ^gPQaL Vernier Rheostat J^K The Rhro.t.t with jtpH^k . 1000 Filament write lor lull ^^^t 2rsr ^pf $1.40 diacounta. ™ MICROSTAT COMPANY WILLIAMSPORT, PA. To the Man with an Idea I offer ■ comprehensive, ripen enced, efficient service (or his prompt, les-al protection, and the development of his proposition. Send sketch or model and descrip- tion, for advice as to cost, search through prior United Slates patenta, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable me to accurately advise clients as to probable patentability before they go to any expense. RICHARD B.OWF.N.Pnisnt u.y, 91 O.ftn Bultdlns. Wftihlnstnn. D. C. M7«-r> WMtvftrlh Bids.. Ntw Y.r« City Radio to Decrease News Costs Far East and Pacific Island Tolls Now Too Costly for Commercial Relations Hp HE scheduled agendum of the Com- mcrcial Congress of the Pan-Pacific Union, opened with consideration of "Trans- pacific Communication," introduced by a comprehensive report by V. S. McClatchy, publisher of the Sacramento "Bee," regard- ing cable and radio service and suggestions for improvements. Particular attention was paid to news communication as foundation for knowledge and understanding necessary for promotion of peace and enduring com- mercial relations among the nations of the Pacific. There are two cables across the Pacific — one from San Francisco to Shanghai via Hawaii, Guam and Manila (Cavitc) ; the other from Vancouver to Hong Kong via Austrialia, both controlled by British inter- ests. One carries news from Canada to Aus- tralia for 5 cents per word ; the other, from San Francisco to Manila for 27 cents per word. The British government encourages news interchange with its dominionsxby forcing the cable companies to give a low rate for the service; for instance, 7% pence from London to Melbourne. The United States has sought to secure similar results by using its Navy radio for transmitting news between San Francisco and Manila for 6 cents per word; between San Francisco and Honolulu for 3 cents. The report declared that radio rather than cable must be looked to for the immediate future for increased transmission facilities on the Pacific. It was pointed out that a request from China would secure the use of the United States radio station at Pekin for news inter- change with the United States through relay at Manila, pending the time when the Federal Telegraph Company of California will have considered its great station at Shanghai for direct communication with California; that Japan can now use her stations in coopera- tion with the United States Navy station at Honolulu for news intercourse with Uncle Sam without violating her exclusive contract with the Radio Corporation of America as to commercial messages between the two countries ; that in this way news rates with China and Japan could be reduced at once from 32 and 27 cents per word, respectively, to a maximum of 9 cents; that Australia can reach Honolulu now by cable to Suva and wireless through Tutuila, and later by wire- less direct through her proposed great sta- tion ; that the Dutch East Indies and French Indo-China have already contracts with the United States navy for radio communication for commercial messages with the United States through Manila, and that the Navy Department will cooperate in establishing a low news rate with these countries. PATENT four Radio Id*-.. Call ftr WrMs FREE ADVICE Reducing Antenna Resistance IT is the antenna charging-current at the transmitter that produces the signals at the receiver, and in order to get a large antenna current with tube sets, resistance of antenna systems must be reduced to a mini- mum. In addition to the usual metallic earth plate a counterpoise, consisting of a num- ber of wires spread on the ground under- neath the antenna, will materially reduce the total antenna-resistance. The antenna should be constructed and supported so that its elec- trical period will not vary through swinging. As will be seen, most of the tube circuits shown in this bulletin use the antenna as the capacity clement of the oscillating system. ro«^IS?0 FIFTH AVE NEW INCREASE YOUR CRYSTAL RANGE BY I 8INO A "IT" 1 I.TRA-8ENMT1YK CONTACT IN YOI K CRYSTAL DETECTOR 1. B sssajusti la a M««ad. 2. Smutm mwi Matlttv* result*. 3. la alflMal ifKpat.ibie to Jar •irt. Priesj twtaty-ftv* «*ato iltovr. "PT" CRYSTAL CONTACT CO. Box 1SJ1 BOSTON a. Those Broken JgUP. Dctcclon 53.50 ^plificr*. Vacuum Tubes Can B e Repaired • nfl Guaranteed Taal If your dealer gt\\ IS4 ay.* rated Sim CirtCINfMlt. Ohssa Over 50000 H0MCHARGERS in Use Subscribe for RADIO WORLD. $600 a ■Sasaaaa* 1 1 f)f\ sa.s» tl CA sksaa Novo B ATT ERIE FOR RAD 22^-45 & 105 yO N OISELE DEPENDADC: GUARANTEE] ■ ASK YOUR PEA LEI NOVO MAM FACTLRI\C?0. f*iy 531 SO DEARBORN ST,CHICAGO

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RADIO WORLD AdYertismg Rates, Display, $5.00 per lack, $15000 per page Radio Merchandising Classified Qwick- Action Advertuiag , 5 ccatt par ward Telephone Bryant 4796 Let Radio World Test Your Goods A Chemical Liquid Manufactured by Krystal-Kleer Co., 2378 Third Avenue, New York City KRYSTAL-KLEER is a recent chemical dis- covery used in cleaning crystals when they become covered with oil from handling. It is a combination of chemicals and is very power ful, acting immediately when applied to surface of the crystal. It also makes it sensitive to the slightest touch of the catswhisker. All else nefded is an ordinary nail-file File the surface of the crystal a little, then with a drop of thia chemical on a small piece of absorbent cotton, rub the surface thirty seconds. What One Advertiser Writes About Radio World Results CHAS. FRESHMAN COMPANY Incorporated 97 Beekman Street New York City November 7th, 1*22. Radio World, 1493 Broadway, New York, N. Y. Gentlemen!— We wish to thank you far your successful effort in getting additional advertising copy on our Variable Grid Leak and Micon Condenser in your publi- cation to appear in the issuo of Saturday, November 11th, 1922. The reason that we sent you the copy at such a late date waa that it has been our pollcy to advertise only one ol our various products in each magaxlne, and we had an advertisement running on our Noiseless Tested Micon Condenser for your coming issue. The results that w; obtained from our first advertisement of the Variable Grid Leak and Micon Condenser combined were eo great that we did not want to miee the opportunity of having it re-appear in the - ba- it might Interest you to know that out- side of the general publicity that our Variable Grid Leak and Micon Condenser . combined received from the first adver- tisement In your publication that we have received hundreds of direct orders from Individuals and payments enclosed mem- tioning the fact that they aaw the adver- St in RADIO WORLD. These In- quiries came from all sections of the We wish to congratulate yon on the exceptional distribution of your publication. Yours vary truly. CHAS. FRESHMAN COMPANY, INC (Signed) Myron Goldsoll Vice-President in Charge of MG:JJ Completely Connected Manufactured by W. J. Radio & Mfg. Co., 3020 Fourth Avenue, South Minne- apolis, Minn. A SHORT-WAVE coupler completely connected. Tested out and found to give wonderful results on the broadcast wave-lengths in con- junction with vacuum tubes. .All one has to do is mount and connect in circuit. There are no taps to solder; no extra switch at aide; no electrical connection to any shaft. Compact and rotor always in center of field. Primary is wound with green silk wire. Of good construction and neat design. Heard at the Radio Counter A Conversation Between Customer and Radio Clerk (Port V) UfAN you tall me if I may use radio fre- V* quency with my set?" "What type set have you 7" "I have a two-stage regenerative set of the audio- frequency type." "Not very well. When using radio- frequency, it must be understood that you will have to remodel your whole set. I would advise you to keep the regenerative set you have on hand and start in building a radio-frequency receiver.'' "Do you think a radio- frequency receiver is better than an audio-frequency regenerative re- ceiver 7" "For the radiophone broadcast listener, I would suggest building a radio-frequency receiver, for these reasons: In the first place, radio- frequency transformers are made to cover a wave-length range from three hundred to five hundred meters, limiting the power amplification between those wave lengths. Secondly, a loop aerial must be used with this type receiver, due to the high power of amplification which would allow the remarkable advantage of eliminating interference net -possible with the outdoor aerial." "Well, that Bounds good. Better gat ma started on this receiver right away!" "Very well. Here is your diagram and make- up of the sat; also, three radio-frequency amplify- ing transformers, three tubas, es (To be continued) Sidbenel Enlarges Plant THE Sidbenel Radio Equipment Manufacturing Company, Inc., New York and New Jersey, manufacturers of the famous Sidbenel A and B Battery, which proved so successful that they are compelled to increase their production facilities and enlarge their plant in order to catch up with the demand for their batteries and various other products. This firm has acquired the services of Sidney Isaacson, a prominent battery engineer. He has been appointed general sales manager for Greater New York, with offices at 1663 Jerome Avenue, Bronx, New York City. New Firms and Corpora- tions (The firms and corporations mentioned m these columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) 1 Automotive ft Radio Manufacturing Corp., Wil- mington, $1,000,000. (Corporation Trust Co. of America.) H. W. Wolcott ft Co., Buffalo, electrical and auto works, $30,000: H. W. Wolcott, A. G. Wick- man. (Attorney, G. G. Smith, Buffalo.) Multiple Battery Sales Corp., Manhattan, $10,- 000; J. F. Russell, Jr., N. D. Sturges, J. W. Smith. (Attorneys, Lowther & Smith, 35 Nas- sau St., New York, N. Y.) Rieger Research Corp., Manhattan, physics, electrical and chemical research, $20,000; J. T. MacEvoy, F. L. Judd, H. S. Michaels. (At- torney, F. Klein, 277 Broadway, New York, N. Y.) Radio Advertising Co., advertising, $60,000: Philadelphia, Pa. (Corporation Guarantee and Trust Co.) Weinig-Urban Electric Co., Buffalo, $10,000; R. G. Urban. R. P. Bagley, F. Truacott, Jr. (At- torneys, Messrs. An grot, Buffalo.) Sturges Battery Corp, Wilmington, electric machinery, $3,000,000. (Corporation Trust Co. of America.) Burrows Electric Co., Buffalo, $15,000; E. S. Burrows, F. A. Gannah. (Attorney, C J. Ken- nedy, Buffalo.) Recording Instrument Corp, Roselle, N. J., man- ufacture speed and distance instruments, $700,000; Horace H. Smith, New York; Anthony F. Wall- billich, Newark; Martin Czaring, Roselle, N. J. North Park Electric Shop, Buffalo, $6,000: H. J. Terschliesen, R. W. H. Campbell, H. C Schuhr. (Attorneys, Sullivan, Bagley & Wechter, Buffalo.) American Radio Products Corp., Wilmington, $250,000. (Delaware Registration Trust Co.) Changs of Name Triangle Radio Equipment Co. has changed ita name to Educational Radio Corporation, New York. Coming Events The editors publish news shows and expos! mailing full Inform of RADIO WORLD wfB ghuBy items of all contemplated rastte Keep us posted by SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, inclusive, 1923, George A King, director of publicity, 417 South Dearborn Street, Chicago, UL PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION. Grand Cen- tral Palace, New York City, December 21 to 31. ColweU ft Korbell, Fisk Building, New York City, directors of publicity. INTERNATIONAL RADIO SHOW. Madison Square Garden, New York City, November 20 to 25, inclusive. E. C. Buchignanl, director of pub- licity. SOUTHEASTERN RADIO EXPOSITION. Audi- torium Armory, Atlanta, Georgia, December 4 to 9, inclusive. Co-operative Radio Sales Assn., 2M Peachtree St. SECOND DISTRICT RADIO CONVENTION, Hotel Pennsylvania, New York City, March 1, 2, and 3, 1923. GREAT ADVERTISING MEDIUM Radio World's special issue, "Holiday Radio Gifts Number," issued on December 9. Copy received up to November 29. Radio World. 1493 Broadway, New York. Digitized by Google

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RADIO WORLD 23 "Decrease" in Broadcasting Not Bothering Department of Commerce THE question whether or not broadcasting will die out may be bothering some peo- ple, but not the United States Department of Commerce. During October, 56 stations were licensed to broadcast, and 22 dropped out. This indicates that the industry is in- creasing by about 24 stations a month. On November 3. there were 553 broadcast- ing stations operating, 19 of them on 400 meters under Class B, and the balance on the old 360-meter wave. During the week ending November 4, eleven new stations were licensed to broadcast. With the cessation of the Corinth Radio Supply Company's station WHAU, Mis- sissippi comes off the broadcasting map, there now being no broadcasting station in that State. It is the only State, today, with- out a station. States with single stations are Delaware. Wyoming, New Hampshire, and Vermont — all others having two or more. California is still in the lead. The new broadcasting stations licensed and those dis- continued follow : Supplemental List of Limited Commercial Stations on Ml Meters Radio Co., Macon, Council KFFE — Eastern Oregon Pendleton, Oregon, 100 watt. WMAZ — Mercer University, Georgia. 750 watt. WPAF— Peterson's Radio Co., Bluffs, Iowa, 10 watt. WSAS— State of Nebraska, Lincoln, 250 watt. WNAS — Texas Radio Corporation and Austin Statesman, Austin, Texas. 100 watt WRAR— Thomas, Jacob Carl, David City, Nebraska, 20 watt. KFCF— Moore, Frank A., Walla Walla, Washington, 50 watt. KYC»— Electric Shop, Honolulu, Territory Hawaii. 40 watt. WPAB— Pennsylvania State College, 1 watt WW AC— Sanger Bros., Waco, Texas, 50 watt. New Class B Station on «N Meters WBZ — Westinghouse Electric & Manu- facturing Compnay, Springfield, Massa- chusetts, 600 watt. List of a Broadcastina Stations Deleted During the Month of October WGAV— B. H. Radio Co., Savannah, Georgia. WH A J— "Daily Telegraph" and E K. Kirts. Bhiefield, West Virginia. WHAU— Corinth Radio Supply Co., Corinth. Mississippi. WDAT— Delta Electric Co., Worcester, Massachusetts. WHU— The Wm. B. Duck Co., Toledo, Ohio. WJT— Electric Equipment Co., Erie, Pennsvlvania. KQT — Electric Power & Appliance Co., Yakima, Washington. WPL— Fergus Electric Co., Zanesville, Ohio. WLAB — Grossman, George F., Carrollton, Missouri. WD AD — Harrison, Wm. Louis. Central Kansas Radio Supply, Lindsborg, Kansas. KYG — Willard P. Hawley, Jr., Portland, Oregon. WHAX— Holyoke St. Ry. Co., Holyoke, Massachusetts. WWT— McCarthy Bros. & Ford, Buffalo, New York. WIAP — Radio Development Corp., Springfield, Massachusetts. Rennysen, New Orleans, Union, Inc., Rochester, WBAM— I. B. La. WHQ— Times New York. KFBF — F. H. Smith, Butte, Montana. WCAN — Southeastern Radio Telephone, West Forsyth St., Jacksonville, Florida. KOE — "Spokane Chronicle,," Spokane, Washington. WIAL — Standard Radio Service Co., Nor- wood, Ohio. WDAB— H C. Summer & Son, Ports- mouth, Ohio. WBAZ— Times Despatch Publishing Co., Richmond, Virginia. Entrants for the "Receiv- ing Record" EDITOR Radio World: — I am a reader of Radio World and am deeply in- terested in radio. I have noticed from time to time, different articles on re- ception of broadcasting stations and articles by some one who claims records for receiving. I am now driving at the article in Radio World, No. 31, dated October 28, where Mr. J. A. MerVlein claims a record and says that on October 16, 1922, he happened to tune out WJZ and get WDAP of Chicago, and WSB of At- lanta, Georgia, on detector tube and 110 volts and two variometers. I am not claiming any record, as there are others who may have done better; but I have him snowed in. Kindly ask him to take notice that I use only the detector tube and one coil 4 inches in diameter and 2 inches wide, two variable condensers and only 69 volts. The following are stations heard clearly any night they are on and the weather clear: WOC, Davenport, Iowa; WSB, Atlanta; WDAP, Chicago; WWJ, Detroit; WLK, Indianapolis; KDKA, Pittsburgh ; WGY, Schenectady, New York; WGI, Medford Hillside, Massa- chusetts; WBAD, Minneapolis, Minn.; WOZ, Richmond, Ind.; WIP, Philadel- phia; 4CL, Commerce, Georgia; WJAR, Providence, Rhode Island; WOO, Phila- delphia; WGR. Buffalo. This does not include stations in and around New York City. And also, these stations have been verified. And cold weather has not set in yet for good re- sults. I am also able to tune out the stations around New York and NewarV, if not wanted. That is, if I want WJZ I can tune out WEAF or the opposite, or both, and get WOR.— Walter George McKin- ley, 47 West 37th Street, Bayonne, New Jersey. * » » DITOR, Radio World:— We do not j claim to beat the receiving record of Mr. Mcrklein, but think that we are getting excellent results with the outfit we are using: 4-wire L-type aerial, 40 feet long, 25 feet high. 3-coil tuner with two condensers. Receive, Boston, Spring- field, Detroit, St. Louis, Davenport, Pitts- burgh, and Atlanta— all on the detector alone. Using 3-tube set, we receive At- lanta loud enough to be heard all over the room with Baldwin phones. Chicago, KYW, we are unable to receive with less than three tubes.— Emmett L. Miller, Chappaqua, New York. ft Remember "This Is a Radio Christmas and that millions of dollars will be spent during the holiday time for radio gifts. Why not get your share of this business by advertising in the issue of RADIO WORLD of December 9, which will be a HOLIDAY RADIO GIFT NUMBER? Thru this medium you can reach thousands of readers, who are not only interested in radio themselves, and want new equipment, but who also will give presents to others whom they wish to make radio fans. ADVERTISING RATES: Regular advertising rates In force for RADIO WORLD'S HOLIDAY RADIO GIFT NUMBER, as follows: $150 a page, $5 an Inch. Discount, 10% four times, 15% thirteen times. Forma close Wednesday. Published following Wednesday. Classified ads. five cents a word. Take advantage not only of RADIO WORLD'S circulation, but also its cash-thru-the-mail pulling power. Be represented in RADIO WORLD'S Holiday Radio Gift Number, and reach the many thousands who actually want your goods and are ready and willing to pay for them. Preferred Positions Must Be Booked Immediately. Copy for run-of-paper positions will be received up to November 29. RADIO WORLD, 1493 Broadway, New York Digitized by Google

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24 RADIO WORLD VARIOCOUPLERS READY FOB WIRING Genuine BaJtellta Tube. 4 In. x 3 In., Rotor Ball; All Necessary Brut Hardware. Base Brackets, ate. 11.30 Csaslste Set— 10s, extra far ecctage. ARROW WIRE * RADIO COMPANY Its 7tk An. Naw Yark City, N. Y. VARIOMETERS READY FOR WIRING ! Mahogany Stators, 4 «4 In. I 1 V4 In. ; Mahogany Rotor Ball; All Xtttwr/ Braaa Hardware and l Winding Form Included. $1.5* Csasslets Sat— Ilia, axtra far paataia. ARROW WIRE * RADIO COMPANY 163 7th Ave. Naw Yard City. N. Y. R-C CABINETS Malniaaatta Phenetrash Quality Flalak. Na Drill- l>l af sanela far attacsins raaulrad. Hlaied tea. RETAIL PRICES 7x0 $2.80 7x14 S3. 00 7x10 $2.78 7x18 $3.0* 7x21 $4.00 If your dealer eaeaet supply yau. order dlrert THE R-C MILLS Executive Offices. 30 E. 23d St. New York. N. Y. (Mention RADIO WORLD) "BE C O" RADIO FREQUENCY SET 176 to 600 Meters 2 Radio Frequency 2 Audio Frequency end Detector All on S Tubes. Bissell Engineering Company 101-167 W. 64th STREET. NEW YORK THE GOODMAN 1 PATENT pending The Nlftieat Short Wave Tuner on the Market Only SSJO 4 PP on 1 lb. Send for pamphlet. L. W. GOODMAN DREXEL HILL, PA. Malar , Halifax. N. 8., write! : Delighted. Received Sebsnettady eleerly en eaa tube first tine I tried the GOODMAN. Would have laved money by birylBI eaeaar " 3000 Ohm Sets $3.98 PLUS 20 CTS. POSTACE AND PACKINC Satisfaction Guaranteed or Money Back. We mail phones the day your order arrive*. Every pair tested, matched and guaranteed aa sensitive as $8 to $10 Sets. Circular Free. Tower Mfg. Company 113 STATION ST BROOKLINE, MASS. Answers to Readers TJf ILL you furnish me with directions to make a loose coupler for the follow- ing receiving sets: Two audio-fre- quency transformers, 3 6-ohm rheostats for filaments, .0005 mfd., variable condenser, grid condenser and leak, lightning arrester, one pair of 3,0Q0-ohm phones. I have 2 tubes, 8 inches long. The diameter of primary is 4 inches and the diameter of the secondary is 3 inches. How many turns to a tap are necessary on the secondary coil? — Morris Sicgel, Tacoma, Wash. For the primary, wind 110 turns on the 4-inch coil, using No. 26 double-cotton cov- ered wire. Use 10 taps of 10 turns each, and 10 taps of 1 turn each. For the second- ary, wind on the 3-inch coil, 100 turns of No. 30 double cotton-covered wire, tapped with 10 taps of 10 turns each. Use your .0005 variable condenser across the second- ary coil. These coils should give you a tun- ing range up to 1,000 meters. * • • / have just finished building a standard short-wave regenerative set, using a vario- couplcr of some 60 turns on a primary 4 inches in diameter; and 50 turns on a 3-inch secondary. I am using No. 24 wire on the secondary and No. 22 wire on the primary. My aerial is of the outdoor type, 20 feet long with a IS-foot lead-in consisting of 5 wires. This gives a 100- foot length. There are times when I hear code, but I seldom hear broadcasting. Possibly this is because my aerial runs over a tin roof. What is my approximate wave length? Why can't I hear the broadcasting stations. — Paul Roelser, Baldwin, Pennsylvania. The inductance of your coupler primary is, approximately, 450 microhenries; and of the secondary, 220 microhenries. To just what wave lengths the primary will tune, is merely guess work. Your antenna, undoubtedly is very poor. Doubling the wire back and forth makes the inductance low, neither can the capacity be very large. The best way is to run the aerial, in one stretch, about 100 feet and keep it clear from the tin roof. Then you may tune to 600 meters. We recommend a .0005 variable condenser across the second- ary. With this, you should be able to hear broadcasting. * * * Let me know the wave length I can tune up to with the following equipment: Vario- coupler, crystal detector, primary with 13 taps of 10 turns each on a 4-inch tube, 23- plate condenser shunted across secondary. My aerial if 150 feet long, 8 feet above the roof of a 4-story house. The lead-in is 10 feet. The fixed condenser is shunted across phones? — Michael McCarthy, New York City. With such a receiver, you should be able to tune up to approximately 800 meters. * » * / have just completed a crystal set but can hear nothing in the way of music — only noise. My antenna is of seven-strand copper xvire, about 80 feet long. The lead-in is of No. 14 copper, as short as possible. My ground is bell wire and is run over the kitch- en floor connecting with the water pipe. Is this O. K.f Is the ground connection the right size of wire? — Francis Molaka, Rome, New York. There is nothing wrong with your hook- up. It is another case of poor location for reception with a crystal set. Probably you are too far from any of the broadcasting sta- tions. Improvements on your set might help you. Go over all your connections. According to the Fire Underwriters' rulings, your ground lead must be, at least, No. 14 copper wire. The length of your lead-in should be made shorter. * * * Is there a broadcasting station in Porto Ricof — Hans Mulinos, Tampa Florida. We know of one station, WGAD, operated by the Spanish-American Radio School. » ♦ » Can I use honeycomb coils to load up my aerial circuit to receive Fort Wood? Where should these coils be placed? — Anxious. You can load up to this wave length, which is 1,450 meters, by inserting a honey- comb coil in the aerial circuit. If you are using a vario-coupler, you will also have to load up the secondary coil. This is, of course, for the plain type receiving set It cannot be done with your type receiver, as yours is of the variometer make. » » * / have a two-stage amplifier with a regen- erative set. I hear music and speeches at a distance of 50 to 75 feet on clear nights. I (Continued on following page) "WEB" CRYSTALS Beat Crystal Yet. Stasia Meantime af Colaaa, Silicon & Iron Pyrites •aid under a raplaoeceeat sue rentes; at an dealers er by waul dlrert en receipt af PRICE, 15c Distributed by WALTER E. BATHGATE ROOM 42. 0 CHURCH 8T„ NEW YORK CITY Jobbers. Dealers write ft Triple Moated SHAMROCK CRYSTALS Triple sssunuac of the three sryeule— Galeae. Buusa sad Iran Pyrites. Bald under a repleeesseert naraatee; at all dealers er by stall direct en receipt of PRICE. Sec Distributed by WALTER E. BATHGATE ROOM 42. 0 CHURCH ST.. NEW YORK CITY Maaufestarsra, Jabbers. Dealers write for prises. RHEOSTATS— SOCKETS POTENTIOMETERS SWITCH LEVERS ROYHELE MFG. COMPANY Mfra. af smutty products MS Mercer Street New York Oty Write /or prices — Rtpruentative* wanted PHANTOM-CIRCUIT BUILD TOUR OWN. Tbls marvel of mystery, using no aerial, no loop, no ground, brings In music Instead of statle showers. We consistently hear concerts en Magnaroi, from stations 590 miles distant, audible 100 foot from horn. The simplicity of this set will surprise you. No radio frequency. Complete Instruc- tions with photo of circuit sent prepaid for 60c. VE8C0 RAO 10 SHOP, Bex W-704, Vaeeville. Calif. That Armstrong Circuit Bo much Interest has beea displayed la <■* special article, 'TI8TBD INVENTION OF MAJOR ARMSTRONG AMPUFIM UT 1M.W0 TIMBS," by John Kent, that sup peered 1* RADIO WORLD Na. 18, dated Jaae 34. Its*. Us pahllshsr decided to pat acids a author sf espies for those who were mat a Me te sat aWs lasas when pahltshed. Capias will be seat, postpaid, am receipt of IBs. or aaad hi yaw sabsortptlea, 16.00, tar aaa year (0 tosses), SS.00 six months, or S1.BO three ■seats*, as* subscription will be started with the lasas ass- uming Us article aboat Malar Araustroai^i Amplifier. — RADIO WORLD. 1408 Broadway P ■ s for $6.00. Sub. Do- Vorld, 1493 Broadway. RADIO WORLD IN THE PUBLIC LIBRARIES Many public libraries throughout the country are sending In their subscription orders for RADIO WORLD. Librarians evidently have made up their minds that the visitors to their libraries are anxious to read articles about and see pictures of the latest developments In radio when they are news. If your library has not placed RADIO WORLD on file, tell your local librarian how Interesting and Important la this once-every-aeven-day radio paper. Address: RADIO WORLD, 140S Broadway, New York, N. Y. igitized by Google

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RADIO WORLD 25 Answers to Readers (Continued from preceding page) wish to add a third step. I have heard that a power tube (U-V 202) will increase the volume of sound better than with an ordi- nary U-V 201 amplifying tube. Which would you advise t Which is the lowest voltage necessary to operate the plate of the U-V 202 tube? Will an Acme transformer be suitable? Will Western Electric phones stand the strain of the diaphragm? What are the advantages of using a pmcer tube in the last Step? — George Siebert, East Orange, New Jersey. The power tube would give you greater amplification than would the ordinary U-V 201, as it allows much more current to flow through the plate circuit. The 202 tubes operate best with a plate voltage of 350 volts. By lowering this voltage, the results are lowered considerably. The transformer you mention is all right. The phone may not be strained, but why waste such power in a pair of phones when a loud-speaker will give you just as much volume? » » * In my circuit of a ''super!' how should the loop aerial be connected to the sett Is there any special connections from the loopf How can it be used?— George Moerling. GUns Falls, N. Y. difference even the whistle will be blotted out. The final tuning will be done by means of the loop condenser and the feed-back coil, which, of course, is the rotor of your vario-coupler. Try changing the connections around on the rotor. It may be that the •winding of the secondary is opposed to that of the primary. $4 CRYSTAL SET "THE LITTLE WONDER" Sue UNMOUNTED Wonder in nmme and a wonder in per- formance. Cannot be equalled (or the Krice. Catche* distinctly everything roadcasted within JO mile*. Send for FREE catalog, describing oar "Little Wonder" act and lieting radio •UN- GUARANTEED, TESTED CRYSTALS Galena and 9A- Radiodte.. *>wt- RaeM-O-PUta Panola. AO eiae* eat to order. Holloway Electric Supply Co, Inc. m Third Avium New York Cttjr VARI0 COUPLERS Wm mho makm t other ttyUm That List $2.50 up Jobbers — Dealers — Agents Writ* for Discounts Jewell Radio Sales Co. 90 West St New York City Phone Rector IMS I Want a Radio Worker In Each Community To Work For Me M; nrt its ta elaatr he mas* mm tad we* km **n hour, ar fail Un* at hen* sad wleb Is ears tnm ts.tt ta 141 10 wMtlj. dapandlni as Un* r*a dno Is It 11 h M nuB* sen. but I Mm ww nwtgsu* isaiita Is Islsran taaaaiaHn la Badls will mmkt as will "TANOLCT BRANCH KAN A U KB," M spsr- •u a brucb far u* la their baas*. Waasaet. easy wars, a* ■mebj, Innarlltls pranta Ns atparlasaa ar ajialal talasi* aasaaaarr. we faralah eawplau estm. trala raw far lb* sari, and assist rm Is katloV ini an a bustnaa* rm will t* sraud at Daa't wait aaUl anathar (nam thla asTar. writ* tads* far Blaratws, sad naks mar apart Wan earn. TANGLEY CO, 187 Main, Muscatine, lows No Experience Necessary tw* hZT To Ground' Design la show windings, also connsct.on* from loop, aa requested by Mr. George Morebng. The accompanying illustration shows how the connections are placed on the set you describe, utilizing the loop aerial. * • * Where is the broadcasting station with call letters OKYX.—Fred Edwards, Lostine, Oregon. There is no such call letter assigned to any station as yet. ♦ ♦ * In making up the Armstrong superregen- eratrve receiver, I have experienced a "pea- nut whistle." This sometimes develops into a sound like a hiss or a water fall. My tickler coil, of ball, is 4 inches in diameter wound with No. 24 enamel wire and has about 90 turns. The Alter condenser is not affected; neither is the potentiometer which feeds the coupler. — Vincent Galloway, Omaha, Nebraska. The "peanut whistle" you describe is the correct whistle to obtain. It should not be very strong, but it proves that your oscillat- ing tube is O K ; or as we say "She motes." The connections are correct. We suggest that you get the switches on the primary of the vario-coupler at the exact adjustment for 360 meters, otherwise you will get nothing but the whistle. If there is a very great "TUNING IN" TO THE RIGHT TUNE IS VERY SIMPLE WHEN YOUR CONNECTIONS SOLDERED WITH THE NEW ii POST SOLDERING IRON 99 POST ELECTRIC COMPi\NY M EAST 4ZND STREET, Dhr. M* NEW YORK FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Plmu send me RADIO WORLD far _. 1493 Broadway, New York City. flBOwwv^fcf 9 ^aywww^wT #w) please mud enclosed $ SUBSCRIPTION RATES: Magi* Cow* -I-** lures Months LSI mm Months JJB Jas Year (S3 Issnee) LOO Add HM a Year for F orates

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26 RADIO WORLD During the Month of December 22% Volt -B- Battery FREE with $15.00 purchases SPECIAL XMAS CRYSTAL SETS Complete with phone, newest type $12.5* Complete with head set, Volta make 1S.0S Federal, with head set VJ» Aeriophone, with head set IMS You are going to be well pleased with any or. the above sets, they are all tested before leaving our place. Aerial when buying set.... US SPECIAL XMAS TUBE SETS Complete with head set and tube, Volta make tBM Westinghouse R. C. with tubes 1MJM Acniephone, three tube set, and loud speaker, with tubes TiM SPECIAL XMAS KEY AND BUZZER SETS You will be well pleased with what we offer (or ISJS You are sure to like the Blinker type, with bulb IJ» PHONOGRAPH ATTACHMENTS For single phone, fits any Phonograph or phone IS.75 For Double Phone, fits any Phone or Phono- graph MS For Just one phone to attach on Horn (state what make phone) 1.SS COMPLETE RADIO SETS in Upright Phonograph Cabinet Beautiful mahogany cabinet encloses the Tuner— 3 stage Amplifier, Storage Battery— "B" Bat- teries, G. E. Battery Charger, loud talker, 4 vacuum tubes. All accessories required for in- stalling the outfit are supplied. These outfits, when shipped within 20 miles of New York City, are installed free of charge. With one year serv- ice guarantee. Above Price* Are Good Until Christmas TRIPLE COIL MOUNTINGS Complete with Flexible Leads *US HEAD SETS Western Electric, brand new in sealed boxes. IMS Federal, 2200 ohm, brand new in original boxes •••• Seibt, imported set, adjustable »-•■ Kellogg, lightest head set made and perfect throughout SJS LOUD SPEAKERS MAGNAOX, type R3 *»••» King Amphtone, were $12.00 IS* STANDARD OR ARKAY *J» DUO LATERAL COILS DL-25, 35 and SO $»JS DL-75, 100 and 200 -SS DL-250 •« DL-1250 "5 DL-1500 lM DL COIL PLUGS Complete with strap Broadcast Bill's Radiolays By William E. Douglass FOOTBALL never used to make much of a hit with me; I liked baseball an' shinny, but what I could never see wuz why those fellows had to go out on the field to fight. Why couldn't they put the gloves on, then stand up an' do it right? But last year when I bough; this set an' started in to listen to football games sent play by play I saw whac I'd been missin'. Now I can tell you every game them college fellers play— you never ketch me very far from my set Saturday. The "Demons" here in Brus- sels Sprouts are playin' every week ; we've trimmed the "Canton Warriors" an' the team from Quivver Creek. The "Tigers" down at Goose Grease Creek were all we had to fear until we played 'em Satur- day, the big game of the year. On Fri- lertrwtlea Boat tf tka RADIO READING COURSE $1.97 THIS IS THE 'HOUSE OF NO REGRETS" We shall be v^l^^if^^^ day night I strung some wires right near the home town bleechers to use a« an antenna an' pick up the football features as they were bein' broadcasted by Station XYZ, an' that way keep the crowd in- formed on games they couldn't see. The game between the "Tigers" and the "De- mons" wuz the one to tell which team, this year, would be the county champion. So you see it meant a lot for Brussels Sprouts to win an' keep on bein* Cham- pions like we have always been. Before our game had started I tuned in a sending station to show 'era how my set would work when gettin' information. An' then our boys come on the field, the game wuz 'bout to start so I left Min to mind the set because you know my part whenever there's a big game is to lead 'em in the cheers. I guess that's why our team has never lost in all these years., I led a snake dance on the field betwee the halves while Min wuz gettin' all t college scores as fast as they come She give a kid a dollar so's to telegra; that station to broadcast out our footb scores all over this here nation an' t 'em we were winnin' — had the "Tigers" the run. Well, sure enuf, they did 'fore the second half begun. (Copyright, 1922, Westinghouap J?'—* ""*ilv-'quote prices. UISLIUI SI I ALLIED RADIO COMPANY. INC Dept. D, 44S SEVENTH AVENUE, NEW YORK CITY, Fltxroy S7M WARNING TO OUR READERS! RADIO WORLD accepts subscriptions thru the American News Co. and its branches, the regular news trade and subscription agencies. No others have any right '•- solicit or to accept payment for subscriptions unless they can show a • kerned subscription authorization from this publication. WORLD, 1493 Broadway, N. Y. C. l*» rn how to drilrn. construct. Install, operate and main- tain all kinds of radio apparatus. Ns todleaa study. A complete radio education, (tourse edited and approved tar Pref. 1. H. Mereereft Up-to-date, accurate, complete. SEND NO MONEY. Juat send your name and address and pay poatman onlr 11.91 and you own thle fin-book Hadlo Library. Write today. Dept. RW4. RADIO COURSES, las., 952 7tk Areas*. Now York A Completely conneetaal coupler. Simply mount and connect In circuit. No taps to solder, no extra switch at side, no electrical connec- tion to any abaft. Compact and rotor al- ways In center of field. SS turns No. a Sraan silk wire on primary. PestaaM Complete wits InSI eater ana $6.50 Sam soapier with rotor towers' ess sad «» CA wlthest asocial eeaeettlese ♦*« Kseakdesis coupler *lth prlated sjladlas «1 CA dlroetless, •ouplete, less wire tW" The W. J. Radio ft Mfg. Co. 3020 Fourth Ave., So. MINNEAPOLIS MINN. Do Your Buying At PERMANENT RADIO FAIR Hotel Imperial 32nd Street and Broadway New York City Buyers — ■ Dealers — Badio De- partment Managers, Demon- strations of Any of the Pro- ducts of the Exhibitors. Only Products of Bepresentative Manufacturers Are on Display. Nearly 100 Manufacturers Now Exhibiting osal THE ATLANTIC &. DACIFIC Mcme of Perfection — > radio company . vi.^tnUi tii^ineer s^oai;~ -•sa'.aaio work just as the turbine :'ngineer is a mechanical engineer specializ- ing on turbines. Radio engineering requires a very high-grade of school training. To be a success — and being a success means more than just getting away with it — the radio engineer must be able to tackle any kind of a radio engineering job, from the making of a simple receiver, scientifically designed, to the complete laying out of a high-power arc, spark, or vacuum tube, trans-oceanic or continental transmitter. Not only must he be an electrical engineer of high calibre, but he must be of a high type of individual intellectually. Many of the so-called radio engineers are out of jobs for the reason that they are unable to make an approach good enough to land them a job or because they are unable to write an ordinary business letter in ordinary English. NO FREE LIST! To many anxious inquirers: RADIO WORLD has no free liat. One copy it sent aa a voucher to each advertiser or advertising agent represented in current issues. All other copies are paid for on subscription or through the news trade. Digitized by Google

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RADIO WORLD 27 RADIO WORLD TBLXPHON1. BBTANT 4TII rOBUMBMD ITBT WTOMTOAT (I BATUBDAT OF 8AMB wm THOU PUBLICATION OFT1CM, 14*1 BBOADWAY. NIW TOKK. K. T. BY BBNMBMT BADIO POBUOAXIOMB COBPOBAXION BOUND BUBKB HBNNBMr. MM M. B. BBNMB88T. TIw-PmUm* FBBD a CLABK. hmln 14(1 Broadway. New Tart FBBO 8. CLARK, lfsnegar. 14*1 Broadway. M«r Ttfk ASSOCIATE EDITORS I Fred. Qua 81 B8CRIPTION BATES) (HOT. $«-•• • >» »»••• *» atx ototot ll.SO far three mow Add $1.00 • XV extra far postage t* Ohm* •od foreign countries. Beeript bj sew eubserlbers of the Bret espy ff BAOIO WORLD availed to tbem after eeodl— Mr ardor. U sal instil MkaMMimu. at sala—lpoon order. Advertising rates an l squeal ADYERT18INO RATES: Om mn: On* tuw— (ISt.M. Quarter. Third and Two- thirds M Mi Mat. 1ft 1* am CLASSIFIED ADVERTISEMENTS i _ attar. Harsh It. MM. at the Pot 001m at Not Tat*. Mot Tara. under tba an at March I. 1W. IMPORTANT NOTICE I Walla ever? possible «ara la takaa la state esnsllr metiers at faat aad erdrdan la leahnlial aad general writings covering tht radla laid, aad Una printed la taoa ever with a aarapalaaa 1 for Um farts, tha pabltjbrr dUeudaw ear _ erJbtntr tar atataaaaata ratardlm aueerjens at pataota. arlerltf at claims, tha prapar ajarktac aat at tatholaal preMeaea, ar atbar suitors thai mmj ha printed la faad faith aad aa bawsaaden tarrJahad bj thaw auppaaad to ba truetweruv. IhK atataaaaat la aiada la nad faith and la am The New Wireless I BOUGHT a brand new wireless for the kid, And started in to rig it up with vim ; I stretched the copper wire two hundred feet, And bought receivers made to listen in! I got a tuner and a finder thing, And read a lot about galena point; I jabbed the needle and I whirled the knob, But couldn't get the outfit into joint! Then twice I got new batteries and worked. And once I caught a faint KDKA; It sounded like an S O S from Mars, And seemed to be a million miles away 1 I bought a new galena point aqd monkeyed With wires and grounders fastened to a pipe; I got a two-way switch to stop the light- ning, But couldn't get the thing to work just right ! I got a longer wire stretched for receiving, And painted the arm-piece with paraffine; I got some lead and soldered on the ground wire. And licked up wireless dope complete and clean! And every night at eight we worked and ^ listened — The kid would laugh and I would fume and fret; I hate to call myself a wretched quitter, But I haven't got that wireless working yet! —Louise Hoixingsworth Bowman, in 'The Times," New York. $25.00 Radio Set for $8.25 FOR TWO WEEKS ONLY The famous Sid- fa e n e 1 Company offers one of the finest and most complete receiv- ing sets for a be- ginner for the first time at a re- m a r k a b 1 y low price. No bat- teries or vacuum tubes are needed. You will hear broadcasting sta- tions very loud and clear. Every essential with full directions for in- stalling the set is included. SPECIFICATIONS Aerial wire— 150 feet hard drawn pure cop- per. Insulator*— four porcelain. Detector— supersensitive galena. Cabinet — mahogany finish with hard rubber panel, nickel plated switch points, large switch lever, and binding post. The Sidbenel is a Storage "B" Battery that will last five years of constant use without replacing parts. It will give continuous service for at least six months before it becomes necessary for recharging. It can then be recharged in a few hours to its original capacity, all ready for another six months' use. A Sidbenel Storage "B" is something every radioist needs. Think of the money saved by not using dry "B" batteries, which are of no use after they once become discharged. The Sidbenel pays for itself in six months. It is so ruggedly constructed that rough usage will not harm it. The container is one which is of genuine hard rubber, molded into ten compartments. Size 2%" by 3" by 4*5". Every inch of Sidbenel "B" is con- structed under our own patents. The plates are especially treated with a newly dis- covered chemical that eliminates howling and just why the broadcasting should prove :ient in this particular spot, t may be the fault of this antenna, or lay be the location of the persons who plain," said Mr. Harkness. "There is a ry — radio is so new it is difficult to speak certainty about any phase of it — that ntenna amid steel frame buildings does /ork so well as in the open. -ii ■ th. f-^lf rpav he. it Receivers— leather head band, special cord, and one supersensitive phone. Special two weeks only. Price com- plete $825. Seme set with doable phones $11.50. 22 to 500 Volt "B" Batteries Lasts Five Years Recharged From Any Lamp Socket screeching so commonly found in any other "B" battery. The Sidbenel "B" is shipped to you partly assembled— all you need to do is connect the plates together, and this takes but ten min- utes and is most simple, as instructions are furnished with each battery. Guarantee:— A two-year written guarantee is given with each Sidbenel Storage "B Battery. This is your complete protection. For recharging we furnish a rectifier for AC which costs $0.25 extra. DC current re- quires none. Complete with directions: Ob* Unit, S volts .....t 3JB Two Units, 44 volts 1M Five Units, 11S volts VIM Eleven Units. ZSS volts MM Twenty-two Units, SW volts aV-M Send for free catalogue on parts, and com- plete sets, and prices for repairing vacuum tubes. WHETHER you require two binding posts, a simple crystal set, or one of the standard tube sets with amplifier and loud • MASTER BALDWIN PHONES AN IMPROVEMENT ON WHAT WAS CONSIDERED THE BEST Those whs know. In the radio world, hire alwaya used tha Baldwin Phone, where exacting work wis to be done. It wis conceded to be ellht times more It has been erar- eenattlTe then ear etaac ~Nof eitiifled with even such a meritorious article as this, the manufacturers hare now produced the Master Baldwin Phone, A 40* Improvement In refinement and workmanship. Golaf sttU further, they hare declined the Claroptwne. the moat marrelloua speaker yet produced. Prices: Singles, $9.00 Headset, $16.00 Clarophone Load Speaker, $22.50 THE HOST SENSATIONAL radio development alnoe the Vacuum Tube. After rears of experiment and proof, tide lenalos fixed Badl* detector is now available to amateur and professional operators. Its Introduction marks the third GREAT step In the progress or Badlo — Brat the eryrtal then the vacuum tube and now the wonderful Ffanaphoae. Price. $3.50. sent postpaid. Direct or at your dealers. 1 EAST 42d STREET CLARK & TILSON Digitized bv LjO( new y ORK CITY

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26 RADIO WORLD SPECIAL OFFER For a limited time only Paragon RA-10....J4S Grebe CR-5 $7* Paragon DA-2 . ...5S Grebe RORK «S Price* F.O.B. Rod Beak, N. J. A. V. GREGORY Red Bank, N. J. 42 Broad Street Quality, Design + Workmanship + Material = RELIABILITY Simple to Use Just plug in at Many 110 v. A. C. (yjlamp socket — at- tach clips to bat- tery— turn on cur- rent and you have your own charg- ing plant. A compact portable Recharging unit that will fully charge a 100 AH battery overnight for 5c. to 10c. At your dealers or write King Electric Mfg. Co., Inc. 1(81 Fillmore Avenue Buffalo, N. Y. FRS ALL MOLDED UNIVERSAL COMBINATIONS 6 Unit* In S F. R. 8. Molded Variometer! $6.00 F. R. 8. Molded Varioconplers $3.00 F. R. 8. Molded Bank Windings... tff.00 Bank Winding* are interchangeable for direct mounting on either Variometer or Varlocoupler. Universal — Accurate — Interchangeable A Complete Two-Stage Long Range Receiver Set Includes two Federal Transformers, Condenser. two-molded variometers, molded varlocoupler, three V. T. sockets, filament rheostats, dials. Read 'Em binding posts, switcb points; In attrac- tive cabinet and drilled panel: complete, ready to hook up. A 1126 Radio for $40 F. R. S. Radio Corporation 409-D East Fort St. Detroit, Mich. The Plot Thickens! Another Radioist Picks Up Phone Call and Seeks Aid in Solving Mystery IT DITOR, Radio World :— I am using a detector and tuner made from the blue prints furnished by the Experi- menters' Information Service of your city, and have- secured wonderful results. Using only one step of amplification I have been able to hear a 'phone station (10 watts), WBAA, a distance of about 475 miles. I have heard 'phone stations in 27 different States and Canada ; but there is one thing on which- 1 would like information: Almost every night, be- tween the hours of 10 and 12, I am able to hear telephone conversation between the exchanges of Muskogee, Oklahoma, and Little Rock, Arkansas. The nearest is over a hundred miles distant. I can hear the operator put her party up and also hear them ring, several times each evening. There is only one point in tuning where I am able to hear this. The first time that this was picked up, I thought it was a broadcasting station, but heard central say, "Number 455 is busy." Every night, for several days, I listened to find out where it was coming from as the telephone company here did not ring this number. Later, I could hear the girl say, "This is the Muskogee operator." Can you offer an answer to this? I am sending a copy of this letter to the Bell Telephone Company and the Western Electric Company. I would like to know if there is anyone else who has picked up distant telephone talk— not radio.— Howard Fowler, Rogers, Arkansas. Prize Freak Set Denver Lad Uses Clothes Line for Aerial and Corncob Pipe for Receiver 0RYi^LE GARDINER, seventeen-year- old Dener lad, seems to have developed a freak radio receiving-set that deserves the blue ribbon. "It consists of a small two-cent corncob pipe, with 40 turns of No. 27 cotton-covered wire wound around the stem. He uses a small pencil-clip for a slider, and has scraped bare the wire where the sliding touches. He drilled a small hole in the side of the pipe bowl put a drop of metal in, then in- serted a chip of galena, and fastened a piece of copper wire by means of a brad half an inch down from the galena for the cat- whisker. AH it cost was two cents for the pipe— the Hard Rubber Composition D A NCI C rest of the set was made from pieces lying around the house. Using a clothesline for an aerial, he re- ceived Denver stations with his corncob set » * * His Home-Made Circuit Brings in Wide Range EDITOR, Radio World: I have a radio receiver that I constructed. I am using a hook-up that is original, so far as I am able to ascertain. With this hook-up, using a variometer and varicoupler that I made myself— I picked up, in one night, fifteen different sta« One-tube hook-up as described by Mr. WallU in his letter. tions. I have heard Schenectady, WGY; Denver, Havana, Cuba, Minneapolis, WEAY, WDAP, WOR, WEAF, 9XO, KSD, WOC, WMAK, and others— about forty in all. These stations were heard on one tube only. When I use two stages, I cannot wear my phones with comfort. Using the phones without a loud-speaker, music, at times, can be heard all over the house, on two steps. I am using a radiation U-V 200 with 22 volts on the plate. My set is mounted on old battery-jars cut up into sheets. This makes a good panel. Accompanying this is the diagram for the detector. I would be glad to give further information to any one wishing to try out this diagram.— Joe L. Wallis, East street, Talladega, Alabama. ALLIED RADIO COMPANY, INC. SEVENTH AVENl WARNING TO OUR READERS! RADIO WORLD accepts subscriptions thru the American News Co. and its branches, the regular news trade and subscription agencies. No others have any right to solicit or to accept payment for subscriptions unless they can show a properly signed subscription authorization from this publication. RADIO WORLD, 14*3 Broadway, N. Y. C. To Be a Radio Engineer ^OW the real designer of radio apparatus £~ is the radio engineer, says Arthur R. Nilson, educational director, East Side Y. M. C. A., New York City, in "The Globe." He is an. electrical engineer special- izing; on- r.aai0 work just as the turbine Engineer is a mechanical engineer specializ- ing on turbines. Radio engineering requires a very high-grade of school training. To be a success — and being a success means more than just getting away with it — the radio engineer must be able to tackle any kind of a radio engineering job, from the making of a simple receiver, scientifically designed, to the complete laying out of a high-power arc, spark, or vacuum tube, trans-oceanic or continental transmitter. Not only must he be an electrical engineer of high calibre, but he must be of a high type of individual intellectually. Many of the so-called radio engineers are out of jobs for the reason that they are unable to make an approach good enough to land them a job or because they are unable to write an ordinary business letter in ordinary English. D NO FREE LIST! To many anxious inquirers: RADIO WORLD has no free list. One copy is sent as a voucher to each advertiser or advertising agent represented in current issues. All other copies are paid for on iption or through the new. tre.de.

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RADIO WORLD 29 A Vacuum Tnbe Dry-Cell Set Taat has a wave-lessth •( ISO ta IOOO Meters. OHki aaof Jabbers Write to LINCOLN RADIO CORP. MuillHlartfl IK Wot tM> Stmt New York, N. Y. Law Storage Battery Constant voltage, large amperage. Will ran two months without recharging. Attractive Dealers' Discounts Writ* for Details WILLIAM LAW COMPANY Aborn and Sub in Streets, Providence, R. 1. INSU-LITE P A N E 1/8" —.01 per nq. in. 3/16"— .015 per «q. in. 1/4" — .02 per aq. In. DEALERS : Write for ditcour A. ~ General Merchandise Co. 5 140 Mnrket Street, Newark, N. J. Do You Like Clear Tone— Sharp and Distinct? If so try MARSH'S Vernier Variable Condenser AT LAST Made tn Three Styles. Dial Knob and Straw* Complete. Fully Guaranteed. 27-Plate @ S5.50 SS-Plale @ «4.7B 11-I'late @ S4.25 Hall orders promptly tilled. F. P. Marsh, 145 Nicoll St. NEW HAVEN, CONN. GENUINE Nathaniel Baldwin Phones $16.00 a Pair Do not confuse these with Master Baldwin Phones. ELECTRIC SERVICE ENGINEERING CO. 105 W. 47th Street N. Y. City GITHENS TRUTONE RADIO HORN — LOUD SPEAKER First one to sell on tan day trial Money back Guarantee la been preneuneed tbe biwt en the to expert*. It baa a elear true tone, artery redle fit ■beuld try Truteoe mad eecapare It with ethers. It TOO dea't lad Tnrtaoe the tmt. your Money will t» raronded. It Is seld an s tea-day trial meaey-heei irantee. 1/ set earrled by yrar deeler write as. Distributors and Dealers, write I AUTO PARTS MFG. CO. HIS Trembly Ave.. Detroit. Mich. Radio Amplifiers for the Deaf THE amplification of sound by means of the triode vacuum tube has now passed on from its application to wired and wireless telephony to a means of aiding those of de- ficient hearing, writes Roswell H. Johnson in Science. Its effectiveness is so great that it promises to be to the partially deaf as great a boon as glasses to those optically defective. The use of the amplifier is sure to expand rapidly in this field, although it will be some- what impeded by its expense. The purpose of this, however, is to call attention to the application or applicability of a sound magnifier in various fields of scien- tific work and industry: 1. For detecting distant underground op- erations as in mine rescue or military work. 2. Detecting the approach of a boat, train or automobile before it comes in sight. 3. Detecting the approach of a storm. 4. As a parallel instrument of the binocu- lar prism glasses of the ornithologist, to de- tect bird songs too far to be heard distinctly or at all. It is particularly useful in detect- ing the higher notes that do not carry far and in observing nocturnal migration. 5. To aid the hunter in detecting sounds of distant game. 6. In conversation from vessel to vessel or station to station at shouting distance and a little further. 7. In directing men aboard or on shore. 8. To extend the possibilities of the dicto- graph in detecting evidence of crime. 9. To make possible addressing larger audiences and distant audiences. 10. To make it possible for some women with weak voices to nevertheless speak to large audiences. 11. In accoustical research for the study of subliminal sounds. 12. The detecting of sublimal sounds from animals not now known to make sounds. 13. To make more audible the whispers - or weak sounds of the sick or injured. 14. To make communication by weak or injured less fatiguing. That commercial equipment of good ef- ciency is now readily available may not be known to some of those who might make good use of the apparatus. Claim Flaw in World's Biggest Broadcaster npHERE have been a number of com- ■*• plaints that the world's biggest broad- casting station, WBAY, operated by the American Telephone and Telegraph Com- pany, 24 Walker street, New York City, could not be distinctly heard in the northern part of the city. W. E. Harkness, manager of the station, told a reporter for "The. World," New York, that it is impossible to tell just why the broadcasting should prove deficient in this particular spot. "It may be the fault of this antenna, or it may be the location of the persons who complain," said Mr. Harkness. "There is a theory — radio is so new it is difficult to speak with certainty about any phase of it — that an antenna amid steel frame buildings does not work so well as in the open. "However, whatever the fault may be, it is a small matter. The plant itself, under the roof of the Walker street building, is a complete success. Recently we have been ex- perimenting with remote control by micro- phoning to the West street station. This is done without loss of time, clarity, volume or anything else. "We are still using the antenna on the Walker street building roof at times. Last Friday, we broadcast through it with good results. However, the roof structure is a small part of the plant itself. The actual broadcasting is done under the roof. We could easily put up another antenna, or re- move it to some other roof. What difference does it make what roof we use? The plant itself is in this building." 3-00 V-AC-U-U-M-T-U-B-E-R-E-P-AI-R-I-N-* A V g Save on 1 50 I Save on ~ " u Detectors A | Amplifiers^ n Bapatrlnt all data at an sad saaHUsrs astag » a starts taaeatea tlaawat sash as (as U renewing baled tabes. slarsant ataaas- b bead. Derorest. aT>. Bassese Betas'. B Badlotrea UT-iOO, UT-tOl, OaaafaaBaai E c-ioo, c-ooi. B Deteetars sad Aaaauflsrs tasaliai 1st E *m n Tmt repaired tubes, we warrant, win area F _ yea the eases absolute saaefertlea that ran A weald eepeet ta resales trass asw tabaa, I R I _ . N George H. PoreU C*, law. G W»T ••MCeVILLl MASS. fa V-A-C-U-U-M-T-U-B-E-R-E-P-A-l-R-I-N Q Ws are asw la a soatrisa ta ares suae aatee far mi sent oaaVarles with sesawaa- A reaassabla trial wUl asa- renastutj. a T U B E R E P A I R Amateurs: Wa Pay Pottage Perfection Radio Corp. of America 149 West ad Street New York Clty THIS WEEK WE HAVE "B" BATTERIES 22-H V-amaJl $0 65 22- H V-large LSS 45 V-medium 22S Watch Our Specials Next Week in Radio World RADIO DISTRIBUTING & AUTO SUPPLY CO. 04 West Mtb St. New York City B'w«y-7th Ate Subway. Otb or stb Ave. "V Just What You Want WHETHER you require two binding posts, a simple crystal set, or one of the standard tube sets with amplifier and loud speaker, you may obtain it at the right price at any radio shop dis- playing the Sorsinc Sign. There is a skilled radio man on hand to advise you, too. "It Pay to Bay at tha Sorsinc Start" Mr. Dealer: — If you are a pro&resslTe merchant, you assy display the Sorrinc den. Let us tell you how. Ship Owners Radio Service, Inc. Wholesale Distributors 80 Washington Street, New York SORSINC BRANCHES Beaten. 40 CemMII St. San Francises. SOI MlaslaaSL Baltimore. 1 1 N. Eutaw St. Missis. 530. S. Dearbera St Naw Orleana. 740 Ualsa St Settle. 67 ftluaakls St.

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JO RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT 5c A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS TMa department la Intended -for everybody who waste quick actiaa on abort announcement* covering the birring, esllhig, euli— glng or fwaorei ■srrhsaiaitng in the radio Bold. Reader* of RADIO WORLD will find that it pay* to read the** column* every week. Advertiser* will get a I— lay service here that la, copy received for tbla department will appear m RADIO WORLD on the newa-*tand* tea day* after copy reaches as. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. per word (minimum of M words, Including address), U% discount for 4 coaaocutive Insortiono, 15% far U can— entire linertloa* (S asaatbs). Chances will be made la standing classified ad vs., If copy la reueirea a* thai office tea days before publication, RADIO WORLD CO, 14K Broadway. N. Y. C (Phone, Bryant 471V) VERY INTERESTING printed matter on de- tectors and crystals. Sent on request. Midland Electric Mfg-. Co., Indianapolis, Ind. Manufacturers of Roger* Radio Receivers and Rogers Receiving Radiometers. Rogers Radio Company, 5133 Woodworth Street, Pittsburgh, Pa. BROADCASTING MAP of the United States appeared in RADIO WORLD No. 8. Sent on re- ceipt of 15c coin or stamps, or start your sub- scription from that number ($6.00 (or 52 issues). RADIO WORLD, 1493 Broadway, New York. PATENTS— Electrical cases a specialty. Pre- war charges. B. P. Fishburne, Registered Patent Lawyer, 386 McGUl Bldg., Washington. D. C HELP WANTED— MALE EARN nil to $2SS Monthly, expenses paid, as Railway Traffic Inspector. Position guaranteed after 3 months' spare time study or money re- funded. Excellent opportunities. Write for Free Booklet G-151. Stand. Business Training Inst., Buffalo, N. Y. ISSUES OF RADIO WORLD from April 1 to Oct. 7 (27 numbers) for 15c s copy, or the whole '"JO for one year sad RADIO WORLD, lot for $3.15. Or send as $6.00 for one veer and start with the Brst number. 1498 Broadway, New York. BRILLIANTONE RADIO PRODUCTS Dept. E, 174 Columbus Ave, New York City $3.50 23- Plate Var. Condensers, .0005 $175 4.50 43-Plste Var. Condensers, .001 £25 4.50 Tbordarson Audio Amp. Trans 3.00 5.00 B. R. P. Audio Freq. Trans. (11 tol).... 4.10 7X0 V. V. 712 and Freq. Trans. (Radio Corp.) 6.00 6.50 U. V. 1714 Radio Freq. Tr. (Radio Corp.). 5.50 JO Jacks single open or closed (Firth) J5 .90 Jacks double closed (Firth) 50 MB and .005 Mica Bakelite Condensers .25 .0003 and .00025 M. B. Cond. with Var. Leak... .25 jOOOS and .001 Fixed Mica Bakelite Cond. JO Tub. Grind Leaks. #, 1, IJ4, 2, 2J4, 3 Megohms .45 Arrow Vsriometer X2S B. R. P. Variometer (to 800 Meters) 3.00 ISO Degree Vario Coupler (wound Green Wire) 1.65 B. R. P. Vario Coupler (Panel 4 Lab. Type) 3.» Send Money Order, but do not add postage for mailing. Pier, will come Parcel Post Collect. RADIO HOSPITAL. Radio sets repaired by practical radiotrician, and experimentations under customer's supervision. Mail orders filled MELCO RADIO, 37-A Bedford Street, New York City. PATENTS— Send (or form "Evidence of Con- ception" to be signed and witnessed. Form, fee Schedule, information, free. Lancaster and All- wine, Patent Attorneys, 259 Ouray Bldg., Wash- ington, D. C. NEWS AND GOSSIP OF THE STAGE— Seed 10c. for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.00 year, $2.00 six months, $1.00 three months. New York Star Co., 1493 Broadway, N. Y. CASH FOR OLD GOLD, Platinum. Stiver, Diamonds, Liberty Bonds. War, Thrift, Unused Postage Stamps. False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash seat, return mail Goods returned in ten days if you're not satisfied. OHIO SMELTING CO., 337 Hip- oodrome Bldg.. Cleveland. Ohio. FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO." Write today (or complete list of premiums and our special sub- scription offer. "RADIO," Pacific Bldg, San Francisco, Cal. FRENCH TUBES, genuine (no bootleg with French name), most sensitive and economic. (Good (or detectors, amplifiers, end especially for radio frequency. Will work very snod on two dry cells.) Price $3.25. ATLANTIC ft PACIFIC RADIO CO.. 131 W. 37th St, near Bway, New York. ASTONISHING results Rokay Regenerative Hook-up without use of Variometers — variocoup- lers. switches, taps. etc. ONE SINGLE CON- DENSER CONTROL ONLY. The coming re- ceiver. Simpler than a non-regenerative — better than any regenerative we have tested. Hook-up. $1.00. Money Order* only. Saves you $10.00 la building your own. With properly wound coils. $3.50 post paid. Complete receiver parts on wood base with Vacuum Tube, $8.00. Head set and "B" Battery, $21.35. Express paid. Rokay Elec- tric Co, Ingomar, Ohio. AERONAUTICAL MOTORS, 50 H. P, New $175.00. Weighs 138 Lbs. Complete. Roger* Air- craft, Route 1, Box 8, Ft. Worth, Texas. MEN WANTED for detective work. Experi- ence unnecessary. Write for details explain- ing guaranteed position. J. GANOR, former Gov't Detective, St. Louis, Mo. USE YOUR PRINTS with new Holiday Greet- ing. Harper Syndicate, Columbus, Ohio. WE NEED RADIO WORLD,"" dated April 22 and August 5. If you have copies you don't re- quire, mail to this office and current issues will be sent you for them. RADIO WORLD, 1493 Broadway, New York. INTERESTED IN JOURNALISM 7 The Star Reporter is for Journalists. 50c annually. 5c sample. Box 55, Times Square Station, New- York. Exchange Jolly Interesting letters through our Club I Stamp appreciated. Betty Lee, Inc., 4254 Broadway, New York City. BROADCASTING MAP et the United States appeared In RADIO WOULD No. 8. Bent on receipt of 15e, coin or stamps: or start your subscription from that number ($6.00 for 61 Issues). RADIO WORLD, 14K Broadway, New York RADIO MAN, eleven years' experience in all sides of the game, capable of constructing, in- stalling, operating broadcasting station of any power, desires permanent connection. Go any- where. What can you offer? Evan*. . Mom us Pier 48. N. R, N. Y. C. Are you familiar with all the radio »J mbsls used in the various book-apt published to Radio World f If not. secure a copy of Radio World No. 26, dated Sept 23. In this Issue was a com- plete table of all important symbol* used to radio construction and testing. Send 15 cents for , . . or $6.00 per year, and have snhoerlpUoa •tart with that issue. RADIO WORLD, 14PJ Broadway, New York City, N. Y. September Electrical Ex- ports Showed Upward • Trend PRELIMINARY figures of the Depart- ment of Commerce showing United States exports of electrical goods for September reflect the improved condi- tions which are noticeable throughout the "Suneco" Tube Adapter Eliminates the Storage Battery Price $1.50 Each Son Equipment Company 67 Exchange Place New York DEALERS FREIGHT PAID TO YOUR STORE We are distributors for: Baldwin Hutchinson Radio Co. Eisemann Magneto Corporation Carter Radio Co. Acmestat National Bakelite Socket . Sodder-Rlte Na-ald Aeriotron Sockets Zeta Radio Frequency Transformers Amertran Transformers Write to-day for our price list CLARK & TILSON 1 EAST 42nd ST. NEW YORK industry, the total, $5,238,753 worth, being an increase over the preceding month in the amount of $487,583. The month's total also compares favorably with that for September, 1921. Important shipments of power trans- formers and power switchboards were made during September, the totals, $499,- 755 and $365,348 worth, respectively, ex- ceeding by substantial amounts the heavy export shipments of these classes for August. Motors and motor driven devices also increased over the preceding month, and in general an average improvement of about 10 per cent, is seen in the Sep- tember electrical export figures. Foreign Radio Factories at Work GERMAN manufacturers and industrial- ists have not overlooked the great market created in this country by popu- lar radio broadcasting, says Lloyd Jacquet in "The Mail," New York. Accordingly, they have put their engineers to work and have started their factories and be- gun placing a complete line of radio ap- paratus for foreign consumption, with the old time "Made in Germany" label. In fact, the German manufacturers have been able to undersell any other competi- tor because of the cheapness of labor and of raw products in Germany today. This competition so alarmed English firms, who foresaw the danger of a flood- ing of British markets with goods made in Germany, that a law was passed in Britain prohibiting radio amateurs from using instruments and apparatus of other than British manufacture. The regula- tions went still further and provided that no license would be issued for receiving or sending if even one unit in the installa- tion were of foreign manufacture. This example was closely followed by France, although that country followed a more liberal policy and only recommended the purchase of apparatus of home manufac- ture for purely patriotic reasons. It would be interesting, however, to compare the product of German ingenuity and engineering skill with our own American products. For many years that country has been ahead, so far as works of precision are concerned. The Difference A RADIO transmitter consists of ap- paratus which can generate alternat- ing current at very high frequencies (from 20,000 to several million cycles per second) in a conductor which, at the transmitting station, is called the trans- mitting antenna. A radio receiver con- sists essentially of an antenna which is cut by the field propagated by the radio transmitter, and of detecting an amplify- ing apparatus whereby the minute cur- rents generated in receiving antenna are detected and made audible. or RADIO WORLD. $6.00 a 1.50 three months. Subscribe year. $3.00 si:

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RADIO WORLD BOYS AND GIRLS EARN XMAS MONEY Writ* for 50 KU AMERICAN CHBI8THAS ™ALB. Btfl for 10c > set. When sold. lend uj IS and keep $2. icr Bra*.. »8I E. 23d »t, Dopt 14. Brooklyn. N. Y. IS YOUR TELEPHONE HEAD SET WEAK? 50 Let me remagnet ue it. Guaranteed, in one day good new. Par Set I rewind for higher ohmage. All radio telephone repairing at mod- erate price*. Mail orders attended to. Dealer* write. ROYS, 101 West 42nd St., N.Y. PRICES SMASHED Each nit bu created new frlondi *nd euatonen -Kh tna noult that we now announce draatlc re- duction? in oUr quail t, line*. All food. prep*ld. Send card for complete price M*L you'll be *ur- pruwd. You'll tell jour friend*. A tampl* *»'- lug follow*: COMPLETE REGENERATIVE VACUUM TUBE BET Our Price Other* P*n^ita..lltr^;i»» drilled. II.M $2.4* Cabinet of 3-ply wood to fit panel.. I.5J *•*• Two dUta— each S5e -70 '•4* SUtean twitch poloU with nut. Each le. Tear twitch stop* with not, Been ^ (J BUht binding "poeti.' ' 'Ntoko'l' plated ^ 4$ Twf^len'i.nri'e'iW.^'.^:^:.' .JO .00 1 filament rheoetaL Hl«he*t gnsae. .85 »-»g 1 rarlo coupler. Fourteen tape.... 2.25 4.00 1 23 pl»te variable eondeneer 1.15 3.50 1 tub* eoeket — Moulded.. .45 .83 1 (rid eondonaer and lee* JJ •J» 1 pbene eondtnter .1* I tube •octet tupport. I J -25 II feet spaghetti tuning 8 4o. . . . . .40 .04 15 feet tinned copper connecting wire SD •*5 Blueprint* showing detail* to as- semble •"> •»» $11.32 (20.02 Other article* take* at random (rem Mr let* arte* list are- Detector tube* — Cunningham — NOT rebuilt $3.15 $»••• Crjtttl detector of closed type .00 1-00 Transformer — Audio frequency 2.15 4.50 Double tUde tuner — knocked down. Coll wound 2.30 Loom coupler — knocked down. Coll* wound 3.75 .... Looee coupler Mumbled 7.50 12.50 Variometer — Hardwood tutor* 4X». Assembled 2.25 4.00 met rone— 3*00 ohm* SM 5.00 Eelloggl — 3400 ohm ■ 8.75 12.00 Western Electrle 1300 ohm* 9.25 12.00 Blueprint* giving detail of 2 *tep amplifier 10 .25 Two *tep amplifier — knocked down Panel drilled 12.05 23.5* Two tup amplifier assembled. In cabinet 18.05 15.00 Vacuum tub* *et In cabinet 7«T v the Invention cf the SPIRAL tone chamber (pat- mW P M J I iMdlai). which net only alltwt ue tt market t sanl- ESB >e*F AfSJ BBS net Inttrumint ef the hiihett trade In every rttptet at SBLOB. ^_BBJ BBW „„ dmett aentatlonal price, but five* many exclusive BBBwammmmm* *V stapes over the common eablnet type tpeaker. which is nething but an ordinary horn encloaed in a eebintt — ^tV ^pfr great compactness for a full-sized tone chamber and a ^**SSmam*w— ^ really etmplote tllmlnttlon of metallie, "horn" noises. 8PIR0LA8 tr* ee pedal ly reeemmended tt mutle levari who can appreciate an absolutely pure, natural tone. We make a emplet* line— *f eaualty hlsh-erat* oenttruetlen thrtuihout, with Sue heed-nibbed finishes. ALL SPIROLAS ARE 80LD UNDER ABSOLUTE MONEYBACK GUARANTEE — ten days to tt* and try them tor yturtetf. SPIROLA CONCERT — Complete with special, powerful built-in un't and ttrd ready to book up In pita* of phenol, beautiful mahoiany or eak *19 CA •nlsk. bronzed throat i V vL- ; SPIROLA DELUXE — New. Improved duplex type tor uee with your headset, twt eomplot* speakers In one, eliminating the usual Interference ti|K between phones, tarn* finish as above «t*.o»f Sails black flslsh. nickeled fittings, otherwise same as «Q CC DELUXE W* alt* make tbe DELUXE and black finish types for use with * single loud tpeaker unit In entering state whether tor use with headset tr unit At dealers tr postpaid <C. 0. D. if preferred). L. H. DONNELL MFG. CO. daTaMIS. Be a National Radio Week Booster! Digit The Newest Product On the Market Our WD-11 Tube Socket. Made of first grade Formica. Can also be used with French Tubes. 75c each We also carry the new Spider Web inductances designed Specially for Rheinhartz Tuner. Price $2.50 each V. T. Sockets made with a Formica base German silver shell. Phos- phor Bronze contacts formerly re- tailed for $1.75. Now 50c each We also offer a limited number of Porcelain base Rheostats, former price $1.50, made by a well-known manufacturer, for 50c each Also Variometers completely as- sembled. $1.00 each FORMICA The Popular Radio Insulation. Cut, Grained, Drilled and Engraved ac- cording to your Specifications. $2.00 a pound American Electro Technical Appliance Co. 23S FULTON STREET == NEW YORK Google CITY

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RADIO WORLD The Latest and Most Essential Part of an Efficient Tube Set FRESHMAN Variable Grid Leak and Micon Condenser (combined) Price Only Complete A Positive Necessity The Freshman Variable Grid Leak enables a varia- tion in an unbroken range from zero to 5 megohms, and all intermediate points. The Condenser em- bodied in this wonderful device is the famous Micon — constant fixed capacity of .00025 m.f . Improves Your Set Wonderfully by CLARIFYING SIGNALS LOWERING FILAMENT CURRENT ELIMINATING HISSING INCREASING BATTERY LIFE At your dealers— otherwise send us purchase price and you will be supplied without further charge. CHAS. FRESHMAN CO., Inc. Manufacturers of the Highest Class Mica Condenser Products in the World 97 Beekman Street New York City Antenella No Antenna or Aerial Needed Forms perfect receiving aerial. No outside wires necessary. Plugs into any light socket. Consumes no current. Eliminates most static and saves cost of lightning arrester. Receives in any room of the house. Gives sharper tuning than an out- side antenna. Price $2.00 At Your Dealers — otherwise send pur- chase price and you will be supplied with- out further charge. Manufactured only by CHAS. FRESHMAN CO., Inc. Home of Antenella 97 Beekman St., New York City Mi _ _ „ TESTED con mica CONDENSERS TESTED MICA CONDI cap. .ooa m. r.- ■ MTtNTS KltOIIIO MFG. BY chas. rnt»HM«H co - mew v«mi ciw Assure Noiseless- Absolute ness Clarity of Tone Accuracy Constant Fixed Capacity Micon Condensers are especially adapted for use with Radio- Frequency, Super - Regenerative and other circuits, where an accurate fixed condenser is re- quired. For protection against damage to the filament and the consequential short life of filaments, Micon Condensers are in- valuable. At your dealer*— otherwise •end purchase price and the desired Micons will be sent without further charge. CHAS. FRESHMAN CO., Inc. Home of MICON 97 Beekman Street, New York City Size Price .00025 $0.35 .0005 .35 .001 .40 .002 .40 .0025 .50 .005 .75 .01 1.50 \ Digitized by Google

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[ational Radio Weel December 23 to 30 (inclusive) November 25 15c. a Copy. $6.00^ ▲ (Trad* Mark) L U R A WVP, Where Uncle Sam Broadcasts (C Underwood & Underwood, N. Y.) An Airplane View of the Statue of Liberty and Bedloe's Island, New York Harbor, showing at the left the lofty aerial of WVP, the Fort Wood Radio Station operated by the United States Government. Hook-ups for the Radio Novice, by G.W. May— Page

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RADIO WORLD ■Wessco W. E. SUFPLT AND SBBVIOS COBPO RATION 18 MURRAY STREET, NEW YORK TM Bleeds Seatk af Okanbere, betaeee Breadway ml Chunk Street Our Prices Speak Louder Than Words FREE FREE FREE Witt Every f 10.00 ui Mr Pmtw ■ $1.75 MM v»lt Variable B Battery AERIAL— A. Vacuum Tube Detector Set— "THE SET THAT MADE GOOD IN A NIGHT." "BETTER THAN THE BEST." Complete with RacHotron Tube, A and B Batteries, Phone*, Aerial and Lightning Arrester $35*0 145.00 MAGNAVOX ....... ♦24.00 A Battery. If* ana.. 0 V. . . 010.00 A Battery, 00 ana.. 0V... 1 14.00 A Battery. 00 ana.. 0 V... il.00 HOI utat Swltak Am 70* Hlfk qaallty Dial 05.00 M.al. " ... VarlaMa Dead. 9.00 4S-al. Varlakla Ceed. 4.58 Varieawter. gaaraateed, 04.20 . Uaaaaenkled Varleeeaeler, UaeaanMed Varlanater, laaalatere , Oaateat Petals, daaea. . . arena Baa Bar, tlaaed. ft. 70a " klak i klol ■a lata, ■slate.. aailty'.'. aaahty '$oToiT¥"BAirtB«Y, u« va variable, OUT •UALITV, GUARANTEED, LARGE IS2.50 10.70 11.40 0.70 .01 .10 .10 1.00 1.09 1.40 2.10 1.00 1.11 .00 .04 .01 .11 V., VARIABLE. GUARANTEED, fl.71 B BATTERY. 22 V4 HI8HEBT QUALITY, SMALL SIZE S.Plata Vereler Varlakla Caadeaaer ........ eaaraataaa- Oaaalaa Reaeilte paaato— 7x10. 01.10: 7x10. $1.00; 0x10, 0145: 0x0. .47: ox*, .oo; Oxii, $i.io; 7x0, $1.11: 12x14^ $0^00^7x24 I AM Meeleed^.' T.' Seeke*)! 1.00 MICROSTATB ■ m. aar lanitli Cklrtea Uaatalai 1.40 .70 .70 ItOMOHAIISER HOMOHARGER DE LUXE. . 0.00 .11 .11 .00 -VJt 11.05 10.11 |0.00 Fart Weed Testes Oail,. .......... 10.00 Kaeaedaaa 1-eUse Taalas Oalla... I la. OanaaaMaa Sad flare Taka 014-la. OeanMlttea Rat F|kra Taka 3-Tn. OMaanlttM Red Flkra Taka....... KUfMaavtlle BNu Cans. Takaa. 4-la... Jehae-MaavlUs BRu Caere. Takaa. S-la... 91.10 Oryatel Deteeter $1.00 Marti Jaak 91.50 Twla Aeastar. alPtes BATTERY Tlaa 1.10 .16 1. 10 0.04 1.00 .40 .41 .00 .05 .10 .40 1. 10 1. 10 .00 10.70 .0* .01 M .07 10 01.11 Uatearaal $10.00 WESTING CHARGERS 70a Oaaa Olnatt Jaak.. 05iV ' Pignolet RADIO VOLT-METER ONE INSTRUMENT MAKES ALL TESTS Write for booklet with suggestion for tearing and adjusting Radio Seta. Thousands now in us* gfve abso- lute satisfaction. Pignolet Instrument Co. , Inc. 114 Liberty Street, New York, N. Y. AETACO (Ansrlaaa Eleatre Teekaleal AsoUaaa* Oa.) OFFERS THIS WEEK Spider Wak ledastaaee Call far Rkataaartt Tansr. I2J0, each Una Steak af Wall.Kaeva Maaafa .0005 Ceadeaeare, SaeelaL $150, each •ueea'a VarlesMtare, $3 JO, each Oaaaa'a Varlaaaaolara, $3.75, each Jeflereen Audie-AnoNfyla* 1 Reoelar Priaa $/.**. $4 JO, each Aatevalx. Seeelal Prlee, $17.75, Arkay Haras. $2.50, each Baldwla Phases Tyaa O. $12.00 Pantea Rbaaatata $1.00, each Usatalni Arrartera, Indaar Tyaa. $1.75, each Llshtalas Arraatara, Outdaar Saaaaaalaa Tyaa, $2.00, each Saaalal Fenelea Paaeli cot. $2.00 a Sraleed. drilled aad aairaved ta araV. We awry a seaslete Haa af radle eusetlea. 10a. far Illustrated catalogue. American Electro Technical Appliance Co. ZS FULTON STREET Branch Stores H*7 Broadway New York Oty Digitized by Google

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VOLUME TWO RADIO WORLD rjtatersd as •econd-clau matter, Much M, UO. at the Fast Office at New York, H. Y„ eader the act el March 1, la79J A Weekly Journal, PnblUked Every Wed— day and Dated Satntky, by 1 .Cetvontion from Publication Office, 1493 Broadway, New York* N. Y. VoL II, No. 9, Whole No. 35 November 25, 1922 i Bryant 4795. 15c. per copy, 56MM a Where Radio Kept Vigil Armistice Day '. Underwood A Underwood, N. Y.) Washington, the nation'* capital, city el "magnificent dUtaneas," always sthrul with the echo** of the aaaa who mads Amsrirsn history, haa no place In all Its rut area than ArUsgtsa Cemetery, where rest forever the Wave am who gave thaw Uvea in the canoe of I native land, but that the net of the world alao aught be free. Perhaps there is no snare asaardraJ. a asm I acres where sleep the dead of the United States Amy and Navy. The rows and rows of sssdset aitlislsan of the privates and i of than- officers are, today, a farogionad for the gigantic towers that i assart the aerials of NAA, the station at Arlington. Nothing Is more sOsut than thaas sign-pom ring towers, nothing asarhs asoro ssiiHIntly the grsalmr of saystsry of Ufa. So one may be pardoned, if In their steadfast position as trsnanrittnrs sad receivers of off that Is wonderful and now fat the world, they should be described as the watchers of our soldi or dead, pnrticularty as, year by year. Armistice Day aocoaes* a day of rwvsrwaco. For al Msaa, the Fudilnit of the United States wffl be expected to place a wreath en the grave of the Unknown Seldmr. sa this occasion. Arlington Csnistmy with Ha verdant slopes and sleeping deed on one side, the sileat-Bowiag Potomac River and the busy farms an the other, the greet City of Wash- ington to the south, rod radio's lofty masts towering over all is a picture no American who loves bJ Using Jacks with Vacuum Tubes THE use of telephone jacks in a receiving set has become a standard practice. They provide a convenient and rapid means of shift- ing the receiver from one stage to another. They can be connected so as to cause the insertion of the plug in any stage to light only those fila- ments required for that stage of amplification. Removal of the tele- phone plub can extinguish all fila- ments and permit their relighting by the mere insertion of the plug with- out readjustment of the filament rheostats. Because of this com- pletely automatic lighting and extin- guishing of the filaments through the use of proper filament-control jacks, the life of the vacuum tubes is greatly increased and the drain on the filament batteries is reduced to a minimum. It is always a safe proposition when cmployinr :m tubes — whether a 6-v "peanut," or lj^-volt ■ the filament jack. In it is the best with a rec

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4 RADIO WORLD DX Hook-ups for the Radio Novice By George W. May, R. E. MANY believe that stations sending out the longer waves may be heard at great distances because of the greater wave-length used. It seems to be fairly well established by experiment that long waves do travel with some- what less attenuation than short ones, but there is no experimental evidence to show how much better the long waves are propagated than the short ones. Recently low-pow- ered stations sending on 200 meters have been successful, occasionally in transatlantic communication, a_ re- sult previously thought impossible. The reason that the longer wave sta- tions are heard at greater distances is due to the fact that they are high- powered stations. It is difficult /air -■HUH Schematic Diagram of a simple, compact recetvtng outfit. A TtriosutK la used as • means of in- ductance. The pUte-battsry voltage is ZZ volts. Drawn by George W. May. to send out large amounts of power at the shorter wave-lengths because of the necessarily small antennas used at the short waves. There is apparently much difference in signal strength at different parts of the season. Sometimes signals — ber tween a pair of stations with the. apparatus the same in either station — show the variation in strength as much as four to one, the stronger signals being received in the winter time. It has been suggested that summer foliage absorbs a considerable amount of energy from traveling waves. There is also a pronounced differ- ence between night and day transmis- sion. Signals generally travel much farther at night than during the day ; but transmission at night is likely to be more variable than it is during the day. It seems that, during the winter months, there is not much static, or disturbance, in the receiver, so that comparatively weak signals should be received. If a broadcasting station is sending out one kilowatt of power a tube detector, such as is shown in the accompanying sketches, should give readable signals at a distance of several hundred miles. This distance will naturally depend largely on how good an antenna is used at the receiving station and how well the set is grounded. It will be noted that distances greatly in excess of this are reported, but generally a tube receiver is not used, as shown in the accompanying sketches. By proper coupling of the plate and grid circuits of the tube a regenerative action is obtained which may increase the sensitiveness of the receiver a hundred times in the hands of a skillful operator. On a number of occasions the writer has copied signals in his laboratory from stations several thousand miles away, using only one tube. Let us consider just what must take place in order to catch the ether waves and make them audible. Some arrange- ment must be utilized to catch a por- tion of the waves as they fly through the air. Such an instrument is usually in the form of what we know as an aerial or antenna. As radio waves have definite frequency, or wave length, some means must be employed to tune the receiving set to the incom- ing waves, or adjust it so the waves in the receiving instruments will oscillate in synchrony, or harmony, with the waves of the transmitter. The instrument of synchronization takes the form of a tuning coil, loose- coupler, variometer, vario - coupler, variable condenser, or, sometimes, a combination of several of these in- struments. I intend to utilize the variometer as a means of inductance for the 360- meter stations. The circuit is simple enough for any novice to work out. If connected up according to the diagram wonderful results should be obtained. From New York City I may say that I have heard WGY, Schenec- tady; WSB, and KHJ, also stations in Chicago, Cleveland and Detroit. The second sketch illustrates the adding a one step of amplification to the circuit. A D-L coil No. 50 can be used in place of the variometer, but I recommend the variometer in order to have some adjustments. The sets and circuits described are simple and comparatively inexpensive ; but it must be remembered that crystal detectors cannot be used for the re- sults I claim no matter how sensitive the crystal may be. Crystals are good for twenty-five miles on the broadcast material, although greater distances can be had under favorable conditions. Code messages may be received over hundreds of miles with crystals. In using this circuit I would recommend using the W-D-ll vacuum tube, known as the dry-cell tube, operating on one dry cell. Believe me, these are the tubes for receiving! They are new on the market. If connections are made properly there is no reason why signals cannot be copied for some dis- tance, provided the aerial is at least 100 feet long. 2Z V ZZ V The amateur wishing to try out the circuit described by Mr. May in the accompanying article will secure satisfactory results by following the above hook-up. Note that a one- stags amplifier is used, which adds to the audibility of loud signals. The instrument of synchronisation takes the form of a tuning coil, variometer, loose-coupler, variable con- denser or, sometimes, a combination of several of these instruments. Any novice can easily work out this circuit, as it is very simple. Connect it up carefully according to the dia- gram. A duolateral coil may be used in place of the variometer, but Mr. May recommends the variometer because of the adjustments. Drawn by George W. May. Digitized by > by George W. May. Google

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RADIO WORLD 5 Combination Hook-up of Detectors By Fred. Chas. Ehlert _j Cc—plsts ■chsaianc diajrwn at a vacuum- tab* doctor outfit with u— stop ■i«pfni ill— m tocriM by FrW. Caaa. EkUrt hi tha kcmwIv artels. 0 NE of the most important parts | of a receiving set is the detector. > It is important in this respect: The human ear cannot receive signals above 10,000 cycles of frequency. In radio work the frequency sometimes runs as high as a million cycles, so means must be provided for making «uch high-frequency signals audible to the human ear. The detector does this. Therefore it is necessary to get the best results from detectors. There are a number of detectors in use at the present time. They are the crystal, the magnetic, the Fleming valve, and the audion- or vacuum-tube. Crystal detectors are of different types: they are manufactured of vari- ous minerals. Galena is one of the minerals used mostly by amateurs. The operation and assembly of a galena de- tector is simple. Crystals must be kept clean in order to retain their sen- sitiveness. Washing with a little al- cohol greatly improves them if they have been left standing, or have been handled, for a long time. The accompanying diagram illus- trates the complete schematic diagram of a vacuum-tube detector outfit with a one step of amplification. A crystal detector is included also in the circuit The amateur should try out both de- tectors separately. The hook-up shows both detectors in the circuit. When using the vacuum tube as a detector, care must be taken that the switch in line with the crystal detector is open. If the crystal is to be used, merely close the switch, shut off the rheostat on the detector tube and adjust the crystal. With the aid of the one-stage amplifier, it will make possible the amplification of signals. Many amateurs would rather use a crystal detector than a vacuum tube because there is less bat- tery noise and distortion. Others, how- ever, prefer the vacuum tube as a de- tector; so, for these amateurs, the vacuum tube may be placed in action and the detector crystal eliminated. With the aid of an extra stage of am- plification, signals will be amplified to a certain degree of sensitivity. A novel effect would result if both detectors were lined and each one tested out separately. This would give an idea as to what both detectors do. It is an interesting experiment for amateurs. Over 600,000 Hear "Aida" by Radio Verdi'. Great Work U Broadcast Suc- cessfully With Metropolitan Singers and Orchestra By Patrick Nichols AIDA," Verdi's grand opera, was heard by radio, on Armistice Day, it is estimated, by over 600,000 people with- in a radius of a thousand miles. The performance was given by members of the Metropolitan Opera Company and the Metropolitan Opera House orches- tra, in oratorio form, in the Kingsbridge Armory, New York, the largest armory in the world, where over 15,000 persons assembled to hear the performance. While the rendition marked a high spot as the program of the Armistice Day Festival in the Bronx, New York City, it will go down in history as one of the most important radio events of the year. Those who tuned their receivers on the 450-meter wave-length of VVEAF, the huge broadcasting station of the Ameri- can Telephone and Telegraph Company, will be proud, in years to come, to tell about this first "radio performance" of one of the most popular grand operas ever written. Voices and instruments were heard with remarkable beauty and clearness. No effort was spared by the broad- casters to ensure reproduction of the opera by wireless without distortion. Engineers of the American Telephone and Telegraph Company spent a week in the armory making tests. They were handicapped by their inability to bold a rehearsal, but, as an alternative they personally sang in different parts of the huge armory to assure themselves that the average human voice could be re- produced with fidelity. They also ex- perimented with a half dozen canaries to make sure that the amp'ifiers would catch even the finest phrasing of the Metropolitan singers. Commenting on this remarkable achievement, "The American." New York, says: "Such glorious broadcasting suc- cessfully accomplished, it loo'<s as if popu- lar musical pleasure and general musical culture were really 'in sight."'

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6 RADIO WORLD With the Ossiphone Even the Very Deaf May Hear Radio RADIO is wonderful to all who can hear, but what about the poor fellow who is deaf and can't hear a sound of the concerts which flood our ears? Does he think radio so fascinating? Ordi- narily not; but with a little instru- ment, the "ossiphone," even the totally deaf who have not heard a sound, for scores of years, may lis- ten in at the radiophone. The ossi- phone may be the means of bringingr a chest of gold to those who for- merly had not even a penny. It is a simple instrument, in- By Ortherus Gordon vented by Mr. S. G. Brown, of London. It is not a means of am- plifying sound so as to overcome all degrees up to total deafness; nor does it translate sound into some other medium of communication, like motion or color. It conveys sound to the brain without the aid of ears, eyes, tongue, or touch; but it does enlist the aid of the bones. It is just what the word says — a bonaphone ; "ossi" is Latin for bone. Plain Dish as Loud -Speaker Distributor - ■ ■ ■ The lowly china, or earthenware, dish, each as may be found in any home kitchen, make* • ■urprialntiy good distributor for a loud-speaker. Take one earpiece from your handset and suspend it in front of and facing- the dish after it has been put end upwards on wood or some resonant material. By careful tasting you can find the exact spot where the sound is the loudest, then the phone may be permanently suspended or fastened, as is shown in the photograph. Surprising mellowness will result. The experiment is wall worth trying whan you are picking up loud stations. In the photograph, 1 shows the disc, or plate, In position; 2 is the telephone earpiece; 1 is the rheostat to increase the brilliancy of the vacuum tubes; 4 is the dial that governs the tuning qualities; S is the receiver complete. In appearance, the ossiphone is a small ebony box, possibly 1 inch high and 4 inches long. From a slot in one end protrudes a metal vibrator with a knob, so that the entire instrument looks like an en- closed telegraph-key. Double wires leading from the other end heighten the similarity. The re- semblance disappears, however, when the cover is off. The vibrator is seen to pass between the poles of a horseshoe magnet which have been wound with wire so that the ossiphone is made to resemble the inside of a telephone receiver with a bar vibrator instead of the usual diaphram. For use with a radiophone, the wires of this useful device are con- nected to a radio receiving set in place of the headphones. A deaf person, perhaps, may not be able to operate a radio set, for he must hold his ossiphone in one hand while he presses its knob against a finger knuckle of the other. Strange as it may seem, he hears exactly the same sounds as a listener-in, who can hear, with a headset. The dif- ference is this: he hears through his bones ; the other hears with his ears. Remarkable tests made in Lon- don demonstrate that a person with normal hearing can actually hear better over the radiophone by use of the ossiphone than by use of the ordinary headset. It is claimed that the bones make better ears than the ears themselves! In explanation of this, it seems that sound is not a product of the ear alone but the effect of the ear's vibrations on the brain. The aural nerves are the ones that do the trick. If vibrations could be trans- mitted to these aural nerves by any means whatever, hearing would re- sult. In an event of this kind, the ears would be merely passive ap- pendages. This strange condition has ac- tually been brought about by the ossiphone. That instrument util- izes the bone as a medium through which to transmit sound vibrations to the aural nerves and thence to the brain. The use of the ossiphone is neither nerve racking nor un- pleasant. The bones themselves do not tingle — the vibrations of the ossiphone are too delicate for that. The only sensation to a deaf per- son is the joyous one of perfect hearing. Digitized by Google

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RADIO WORLD 7 Merchant-Marine Officers of Future Must Know Radio By S. S. Smith IT has been decreed by the State of Massachusetts that the edu- cation of a merchant-marine officer is not complete without a knowledge of radio. Accordingly, the Massachusetts' State Nautical School, the steamship "Nantucket," is offering to cadets, this winter, a complete course in radio operating and engineering. This is a depart- ure from the ordinary curriculum; for during past winters, at North "End Park, Boston, the education of prospective merchant-marine offi- cers has been limited to navigation by the sextant, the log, lead, and compass, fair winds and the grace of heaven. Now, for the first time, merchant officers in the making are being for- tified against storms, currents, and fogs at sea by timely instruction in the use and operation of all kinds of radio apparatus. The importance of this instruction may be judged by the fact that there are at pres- ent only two training ships supply- ing our merchant ships with offi- cers of American parentage: the "Nantucket" of Massachusetts, and the "Newport" of New York. There is a special instructor on the "Nantucket" whose duty is to teach the cadets the Continental Code and to explain radio navi- gating. Fascinated youngsters are learning that there are other ways of obtaining a position at sea than those given in the nautical lore and navigational tables of Bowditch. Study of the radio compass is stressed, as that instrument is of greater value to the seafarer than any other. During the winter lay-up at the dock, the theory of the science will be taught. In the summer, when the "Nantucket" goes on her an- nual cruise halfway around the world, the cadets will get actual practice in the radio room of the ship. In this period, they will have demonstrated to them the possibil- ities of radio navigating — not as it is practiced now but as it may be practiced in the future. This is the first step ever taken to weld the deck and the radio de- partment of merchant ships. Here- tofore, there has been jealousy and ill-feeling — old-timers have felt that radio is an encroachment on their methods. They have balked at using radio. The Navy long ago Tbm Mwiflimm Stat* Nautical which students an (i-ran a brought radio within the control of the navigator; but then radio, as a means of battle signaling, was far more important on war vessels than on cargo and passenger carriers. Some time may pass before radio as taught aboard the Massachusetts' school ship will have a visible effect on merchant marine, but the fact • remains that future officers are be- ing prepared for radio dominance on the sea. Radio -Wire Tables By Frederick J. Rumford, E.E., R.E. No. 2 — Single Cotton-Covered Wire Showing the Number of Feet in a Pound and Fractions of a Pound A PPENDED is the second of a series of five tables which the radio amateur will find useful for many purposes. The succeeding tables— "Double Cotton-Covered Wire," "Sjngle Silk-Covered Wire" and "Double Silk-Covered Wire"— will be pub- lished in early numbers of Radio World. Sise 20 21 22 23 24 25 28 27 2B 29 30 31 32 33 34 35 30 37 38 30 40 H». 94ft. lib. 38 70 152 228 311 389 48 90 192 288 01 122 244 306 491 78 150 312 468 624 97 194 388 582 778 119 238 470 714 148 296 592 888 .a 191 382 704 1146 1533 247 494 988 1482 1903 307 614 1228 1842 2401 301 722 1444 2166 2893 435 870 1740 2610 3483 551 1102 2204 3300 4414 5688 711 1422 2844 4266 800 1000 3200 4800 6400 1049 2098 4196 6294 8393 9840 1230 2400 4920 7380 1454 2908 5816 8724 11030 1731 3462 0924 10386 13848 2258 4570 9140 13710 18288 3047 0094 12188 18282 24381 a variety of purposes. Digitized by VjOOQ IC

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8 RADIO WORLD Radio Waves Penetrate Earth Experiments in Mine Indicate That Radio May Be Used for Communication By Carl H. Butman WASHINGTON, D. C— The well-known signals KDKA, East Pittsburgh, have been heard in many places throughout the country, but it is doubtful if it was heard 100 feet below ground and at a distance of eighteen miles from the station, until the Bureau of Mines experts heard it recently in a test made in a mine at Bruceton, Penn- sylvania. Although the tests were hurried, only short continuous waves being used and no attempt made to modify the apparatus so as to try out longer waves, the experimenters found evi- dence that electromagnetic waves may be made to travel through solid earth. Reporting to the Bureau of Mines, C. L. Colburn, C. M. Bouton, and H. B. Freeman, jr., say that, in re- sponse to many requests for a de- vice permitting the use of radio in mines in the interest of safety, es- pecially following disasters which frequently break mine telephone systems, they recently undertook an unusual experiment, in co-operation with three engineers of the West- inghouse Electric Company. In their official conclusions they state : "The present preliminary experi- ments, while unsuccessful in indi- cating any practical method of using wireless waves for underground communications, nevertheless indi- cate clearly that electromagnetic waves may be made to travel through solid strata. The 'absorp- tion,' or loss, of -intensity with dis- tance is very great for the short wave-lengths used in these experi- ments. Longer wave-lengths are known to suffer less absorption and may possibly be found practically effective under certain conditions." The preliminary experiments con- sisted, first, in receiving signals from without the mine at Bruceton by means of a receiver located inside; and, second, both sending and receiv- ing messages underground through the strata. It was found that with a receiving instrument set at a point 100 feet underground, signals from KDKA could be heard distinctly. About fifty feet from the receiving station used in this test was a six- inch bore-hole from the surface, lined with iron pipe and containing electric light wires which extended therefrom throughout the mine. The presence of these wires evidently as- sisted greatly in the reception, they report, for, when the receiving set was carried to another point re- moved from wires and tracks, the signals were barely audible through New Voice Amplifier at WEAF New York's newest radio- broadcasting* station, WEAF, operated by the American Telephone and Telegraph Company, uses a 'Voice amplifier," as shown in the photograph at the right. This is neces- sary hocanas the mnalc studio and the broadcasting station are a quarter of a mile apart. The new ampli- fier Is a masterpiece of delicate mechanism that will pick up As notes of a bird and start them on their Journey over the air without losing the moot Intricate trilL WEAF was the station through which the opera, "Aide," was broadcast on Armistice Day— e radio event that marked a new era In science and mnalc, for it proved to the world that, because of price or distance, the masterpieces of music may now be given to everyone by voices accompanied by an orchestra that only a few have had the great pleas- are of hearing. Without the voice amplifier, the success of such an undertaking would be question- able; but this new device ie able to convey, without losing even the fraction of a sound, music and the human voice— from any place where they may be produced— to the broadcasting apparatus. Every week records some startling new addition to radio's remarkable equii 'hat makes It more end more of a great «• lerbert) fifty feet of cover. "The fact that signals were detected, however, even though faintly, is sufficient evidence of transmission through the ground to encourage further experiment- ing," they state. In sending waves underground, the Westinghouse 20-watt vacuum- tube transmitter was used in such a manner as to send out continuous waves from 200 to 300 meters length ; but they say that additional experiments with waves of in- creased length are much to be de- sired. It was found 'that although signals could be heard distinctly through fifty feet of coal strata, the audibility fell off rapidly as this dis- tance was increased. In all experiments, the vertical antennae was found to give the better results, the horizontal antennae giving practically no re- ception. A loop of a single turn was used, however, with fair results. AH these experiments were tried with a wave-length from 200 to 300 meters, except the reception from KDKA which was 360 meters. The strata at the experimental mine lie almost horizontal, and may have had some influence on the transmission of radio waves; but the present experi- ments gave no conclusive evidence on this point. They seem to agree, that the degree of wetness of the strata influenced the transmission of radio waves. The mine was a com- paratively dry mine, but the over- burden of soil and soft shale is damp, and a small stream of water is continually flowing from the mine. The underground workings of the Experimental mine follow a hori- zontal five-foot vein of bituminous coal, and the transmission and re- ception inside the mine followed the course of this vein. In order to gain a quantitative idea of the transmission of the radi- ated energy, a milliammeter was in- serted in the plate circuit of the re- ceiving apparatus. This normally read 1.6 milliamperes, but the flow, of radiant energy from the receiv- ing antenna produced more or less depression of the current according to the intensity of the signals. This then made possible a comparison of the intensity of the reception at dif- ferent points. The milliammeter was graduated in tenths of a mil- liampere, and tenths of a division could be estimated by eye. Signals could be clearly heard when the in- flowing energy was too low to be indicated by the meter; that is, the clearly distinguished words from KDKA gave no appreciable depres- sion of the plate current. Digitized by Google

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RADIO WORLD 9 Why Radio Transmission Is Superior to Wire Transmission By B. R. Cummings Radio Engineer. General Electric Company RADIO may be defined as: "A system of communication whereby intelligence is trans- mitted with the speed of light in all directions, for any desired distance, without the aid of any artificial medium, by the propagation and detection of electrical disturbances in space." An analysis of this definition will indicate the unique inherent character- istics of radio which make it service- able where other systems of communi- cation cannot be applied. While the speed of transmission in radio is no greater than that of wire- communication systems, it is equal to it. A radio message travels at the rate of 186,000 miles per second — more than one million times the speed of sound. A radio message, for example, which is transmitted in New York is received at San Francisco in less than two one-hundredths of a second! A radio transmitter will radiate its message in all directions, a character- istic which has made broadcasting possible. A broadcast message can be heard by airplanes, by ships at sea, by submarines submerged in the sea, and in mines or other points under the surface of the earth. So far as we know radio communi- cation can be effected over any desired distance. Radio stations have already transmitted completely around the world, and, since the medium which transmits light to us from stars and planets is the same medium which transmits radio communications, it is reasonable to believe that a radio mes- sage may be propagated through space for a distance depending only on the amount of power which is put behind it. The third inherent characteristic of radio — that is, its ability to transmit intelligence without the aid of any artificial medium — places it in a field absolutely its own. Not only does this permit communication with points otherwise inaccessible, such as, for ex- ample, aircraft, with ships, and to in- accessible spots on land, but it elimi- nates the need of securing rights of way for transmission lines and their construction and maintenance. A radio system is therefore rendered more positive than wired systems in that it is not subject to the failures which frequently occur during the winter months in wire lines. While the means utilized in radio differ entirely from those used in other forms of communication, it is possible to connect a radio system to a wire system so that a telephone sub- scriber, sitting in his home, may talk by a wire line to a radio station, where his voice is transferred to a radio transmitter, transmitted by radio and again transferred to a wire system. This fact makes it possible to extend the range of wire-telephone systems over areas which were heretofore con- sidered impassable by including in the wire-telephone line a radio link which bridges the previously impassable section. While a radio communication is broadcast in all directions, it would be desirable for some classes of work to be able to transmit only in one direction. Senatore Marconi, during his recent visit to the United States, made a plea for further investigation into the possibilities of directive radio-tran- mission whereby the message would be transmitted in one direction only. He pointed out that, in his early experi- ments, he had succeeded in trans- mitting directively over short distances by using a reflector at the transmitting station whereby the propagated waves were reflected and concentrated in one direction similar to a beam of light from a searchlight. It should be remembered that it is Eleven New Broadcasters ADDITIONAL broadcasters licensed during the week ending November 11, as limited commercial broadcasting sta- tions, on 360 meters, are as follows: KFED — Billings Polytechnic Institute, Polytechnic, Montana. WNAQ— Charleston Radio Elect. Co., Charleston, S. C. KFCK— Colorado Springs Radio Co., Colorado Springs, Colo. WNAX— Dakota Radio Apparatus Co., Yankton, S. D. WOAJ— Ervin's Electrical Co., Par- sons, Kansas. WNAW— Henry Kunztnann, Fortress Monroe, Va. WBAQ^-Lyradion Mfg. Co., Misha- waka, Indiana. WNAV— People's Tel. & Tel. Co., Knoxville, Tenn. WRAY— Radio Sales Corporation, Scranton, Pa. WPAL— Superior Radio & Tel. Equipt. Co., Columbus, Ohio. WOAF— Tyler Commercial College, Tyler, Texas. not intended that radio communica- tion shall replace the wire-telephone system. Its use will be restricted to communication between points where wire communication is not possible or ■ applicable. This is due primarily to the fact that the number of radio com- munications which can be carried on simultaneously in a given area is limited, whereas in wire telephony the number of simultaneous communica- tions which can be carried on is un- limited. While directional radio-communica- tion is needed in commercial radio work in order that radio may be made to approximate more nearly the directiveness of a wired system, such development will be intended not to replace wired systems, but to eliminate unnecessary interference in areas not lying between transmitting and re- ceiving stations and to effect power economies in the transmitter itself. It should be remembered that, while broadcasting by radio is serviceable in communicating with moving stations and for broadcasting work, com- mercial radio traffic is usually handled between fixed stations — that it would be desirable to be able to transmit from one to the other without having the message broadcast. The foregoing has referred briefly to the characteristics of radio-com- munication without touching upon the functioning of the apparatus itself. Many people witnessing for the first time a radio transmitter in operation are disappointed, for there is no visible motion in any of its parts. It is noise- less, and there is no evidence whatever of the phenomena occurring in its various circuits. Its operation, however, includes a consideration of both the infinite and the infinitesimal ; infinitesimal units of electricity so small that they cannot reflect light, and, therefore, can never be seen, moving under perfect and complete control of the operator; amplifying the human voice millions of times without distortion and trans- mitting it through space with almost infinite speed. In analyzing the phenomena involved and the almost unbelievable future for this method of communication we may probably be forgiven for modifying Morse's memorable message: "What Hath God Wrought?" to "What Hath God Not Wrought?" Digitized by Google

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10 RADIO WORLD Tunii** con. The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks ]~\OES everything, or certain i J things only, contain electricity ? Everything contains elec- tricity. And everything means just everything — your shirt, your pencil, your shoes, your hat, yourself ! This is similar to the fact that most every- thing contains water. Take apples and 'peaches, for instance. If the water is evaporated we have dried applies or dried peaches. If we could withdraw the electricity from an object there is no doubt that the object would change in some way. * * * How about the movement of elec- tricity? Electricity makes itself known only when it is in motion, or when there is more than usual, or less than usual, of it in an object. This is exactly what air does. If air moves we have wind. We speak of electricity in motion as a current of electricity just as we speak of a current of air or a current of water. * * * Uncs OF, Are there any polarities to elec- tricity? In order to answer this question let us consider what happens when we comb our hair and hear a crackling sound, or the fact that the hair is attracted toward the comb when it is near it but not touching it. This is due to the presence of more than the usual amount, or less than the usual amount, of electricity. In order to more clearly understand this try the following experiment: Take a piece of cork about the size and shape of a pea and cover it with a layer of tin- foil. It will then be shaped like a ball. Fasten this to the end of a silk thread about eight inches long and hang it up. Take a piece of hard rubber — a rod is best, but a comb will do — and a piece of cat's fur, or flannel, and rub the rod with the fur. This should be done in a room con- taining dry air, as damp air lets the electricity leak away. Any room that is heated will answer. The rod now contains more than the usual amount of electricity. It is electrified. You electrified it when you rubbed it with the fur. When a body contains more than its usual amount of electricity it is said to have a negative, or minus ( — ), charge. The fur, which had a What a curat Is psssad through ■ calk of wins, minims si Unas of magnatisai radiate from each wfa-a, winding and twisting about tka eofl. less amount, is positive, or plus (+). * * * What can be said of the positive and negative charges in regard to attraction? Positive electricity repels positive electricity; negative electricity repels negative electricity; positive attracts negative electricity. In other words, like poles repel ; unlike poles attract. * * * Will electricity flow through any material? Charge a large ball with positive electricity and another large ball with negative electricity. Take a silk thread and extend it from one ball to the other. Then test the two balls to see if they are charged. You will find that there is no change in them. Both still have their charges. Instead of using the silk thread use copper wire. Test the two balls and you will find that neither is charged. When we used the silk nothing happened. * * * What is the explanation of this? What happened is this : The excess electricity on the negatively charged body went through the wire to the positively charged ball, which, you must remember, had less than the usual amount. In other words, we had the electricity moving along the wire, forming an electric current. The wire permitted electricity, but the silk How to Put Up Your Aerial A SIMPLE way to raise an aerial mast of a considerable height is to plant a shorter staff about one- third of the length of the main aerial-mast close to the base of it, and raise the larger mast by means of block and tackle. Guy ropes should be slung from the mast about two-thirds the way up, to permit of guiding. It is customary to make the aer- ial of more than two spans of wire so that a greater conducting-surface will be presented. ■ For stations up to one kilowatt in size, an aerial should have at least six wires spaced not less than two feet apart nor more than three feet apart. It has been found that nothing is gained by placing the separate spans closer together than two feet; for fairly large aerials, three feet is good spacing. Other things being equal, the greater the height of the aerial the greater its range either in trans- mission or receiving; but the range is largely influenced by the number of strands in the aerials. Where the height is limited, the aerial may be extended s§ that it covers a con- siderable area. It must be kept in mind that as more wires are connected parallel to the aerial, it will tend to give it greater activity. The capacity in- herent in it is also directly in- creased. The aerial must not be made too large for the transmitting set or there will be a decrease in- stead of an increase in the range. thread did not. Then the wire is a conductor of electricity and the silk a non-conductor. An object that will not conduct electricity is known as: 1 — non-conductor (not a conductor), 2 — di-electric (not electric), 3 — in- sulator (to shut off). * * » Are conductors needed for elec- tricity? A conductor is absolutely needed for a current of electricity ; so is the object to which it is connected. In order to explain further my example of an elec- tric current : We rubbed the hard rubber rod with the fur, and this rubbed some of the electricity of the fur into the rod. The electricity that we rubbed on the rod is not something new or unknown. It is electricity that simply moved from the fur to the rod in very small parts, called electrons. These electrons have been measured, weighed, and are able to show them- selves. It is these moving electrons which makes a current. Of course, to have a continuous current we must keep them moving. Digitized by Google

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RADIO WORLD 11 No Interference Between 360 and 400 Meters By W ashing ton R. Service FOR some time the Department of Commerce Radio Section has insisted that there was no actual interference between the broadcasting stations using a 360- meter and a 400-meter wave, if good sets were used and properly tuned, and this contention recently has been proven. The radio inspector at San Francisco has submitted a re- port to the Radio Section of the De- partment of Commerce, which, it is believed, will be of interest to the radio public. Because of numerous complaints in California that serious interference was experienced by lis- teners-in while two neighboring stations were transmitting simulta- neously, one on 360 meters and one on 400 meters, the radio inspector conducted a personal test which he describes as follows: "I arranged a test with a single- coil tuner and also two inductive tuners located at .a point midway be- tween both transmitting stations. These stations, which were about a mile apart, were then requested to transmit at exactly the same time. It was found that with the single- coil tuner it was impracticable to separate the two waves. However, by using an inductive tuner, a charge of six degrees either way, would tune out either one of the stations. This corresponded to a change of about six meters on either side of the transmitting wave. As the receiving station was lo- cated on almost a direct line be- tween the two stations mentioned, it seemed to demonstrate, beyond any possible doubt, that, with a se- lective tuner, it would be entirely feasible to receive from either sta- tion at will without interference from the other. No doubt there will be much com- plaint from single-coil receivers and from other stations having very large aerials; but it is thought the interference will result in the ulti- mate improvement of receiving ap- paratus throughout the district. A campaign of education is being in- stituted by the Broadcasters Asso- ciation; and it is intended that an inexpensive form of resonance trap is to be placed upon the market, for installation in conjunction with single-coil receiving stations, which will enable operators to reject un- wanted signals, within the range of 300 to 600 meters. Radio from Two Important New Angles By Arthur G. Shirt THERE is danger to the politi- cian in radio— a danger that, apparently, he does not see. It loses votes faster than it gains them. The correspondent of a New York paper, during the recent guberna- torial campaign, struck the idea right when he wrote : When a voter can tit at his home without the influence of the crowd, and calmly analyze the speech of a r lilical candidate as it is delivered, am inclined to believe that it is very disadvantageous to the speak- er. Candidate 's talk, as it came in over the radio, was a fine example of pure, unadulterated "bunk," and when I heard the band play and the crowd cheer, I then realized how easily the average voter is beguiled into believing that he has heard some concrete impor- tant statement that means some- thing, when he is really only being influenced by the general effect of the meeting. Radio is extremely impersonal — it is neither coerced nor influenced by any personality, good or bad. It strips everybody and everything to the same level — forces them to sub- stitute real genius and honest argu- ments for fake cleverness and "hot air." With this analytical coldness in its favor, it is a wonder that radio has not been used in courts of jus- tice where the emotions of juries are too frequently played on by de- signing lawyers to gain ends not al- ways coincident with the ends of justice. Of course, it sometimes happens that the human element in the case before the jury for trial must tem- per the decision and alleviate the National Radio Week Dec. 23 to 30, Inclusive CANADA U anxious to join the United States in celebrating National Radio Week. Harry Lewis, editor of "Radio News," Toronto, has written to Major. J. Andrew White, chairman of the Ex- ecutive Committee, 32*, Broadway, New York, that his country is willing and ready to affiliate.. He believes that the concerted action of both countries would have a good effect on radio in general. Every effort will be made to bring the Canadian fans and amateurs in line. • • • Dr. Alfred N. Goldsmith, eminent radio* ist, inventor, and chief of the radio de- partment of the College of the City of New York, has been appointed chairman of the Committee on Radio Engineers. * * * "The Evening Mail," New York, says ' editorially: A MOVEMENT is on foot to organize L x a "National Radio Week." This is good and commendable and deserves the support of everyone interested in or con- nected with the radio industry. If the jdea develops into more than a threat and is actually carried out it will do much to- ward stimulating business. Incidentally The Evening Mail sug- gested a similar plan in these very col- umns last August that should show The Mail's attitude pretty closely. If the sponsors of the present move- ment can show some interesting action, they can rest assured that the columns of this paper are at their disposal. There is another movement on foot to raise $50,000 among the manufacturers to advertise radio on a national scale. All these movements are good, but they should have been planned months ago. In- stead manufacturers sat 'and waited until the last minute for something to happen, confidently expecting that radio was so good that it would sell itself to the pub- lic with practically no effort on their part. This theory has been exploded and now we have desperate last minute meth- ods, which are always more or less hap- hazard, to revive the industry. The best thing in the world needs sell- ing power behind it and radio is no ex- ception. We have a market before us as big as all outdoors. If the manufacturers do raise $50,000 for an advertising campaign, let us hope that it will be spent wisely. If half of this sum was expended on programs and the ether half on advertising the programs, no doubt the radio industry would receive a much needed impetus. punishment. More often, however, is it necessary to administer stern and impartial judgment. If the jury does not see the prisoner or the law- yers, but hears testimony and argu- ments by means of a radiophone, will it have a better chance of ren- dering a fairer decision than other- wise possible? Here is a question that may puzzle the minds of econo- mists, thinkers, jurists, and crimi- nologists for some time to come. Whatever value this suggestion may have, the use of radio as a re- lentless mirror will warn politicians and others who use it for their own ends that the radiophone is a dan- gerous toy for them to play with. Digitized by Google

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12 RADIO WORLD How to Make an Intermediate-Wave Regenerative Receiver with a Wave Length from 150 to 3,000 Meters THE panel is 18 inches long and 6}4 inches high. It may be bakelite or hard rubber. The shielding in front of the condenser and inductance may be copper or aluminum. It is connected to the ground terminal of the set. Care must be taken in shielding the panel as the plates must not touch the shaft of the variometer or any metal parts of variometer or condenser. The condenser is a 43-plate .001 mfd. and is inserted in the antenna. The variometer must have a rotor ball measuring Zy2 inches over all. A card- board tube is used measuring 4 inches inside and 4 inches long. It should be given a number of coats of shellac to prevent it from shrinking after it is wound. The winding is bank wound, 3 layers, 87 turns to a layer started % m - m By Joseph Schuck Hook-up for tho refeaeratlre receiver, 1SS to J,Mt motor*, aa described in the acconipanjrlag inch from the end and 11 taps taken off the first tap at 3, the second tap at 5 and 8 thereafter. Two taps are taken off the variometer at the stators as seen by the drawing. The inductance is then mounted on the variometer by means of two small V brackets. Care should be taken when mounting. The winding of the inductance must run in the same direction as the variometer winding. The rotor of the variometer must also be able to pass freely when turning at the inductance. The audion socket is to be mounted on a shelf by means of set of V brack- ets. The shelf is of hard rubber, or bakelite, 4J4 inches long and 3 inches wide. Three battery posts are also mounted on this shelf. The rheostat is mounted directly under the socket shelf, thus saving space and giving the set a better appearance. The phone condenser, C 3, is an .0025 mfd. The grid leak and con- denser is combination type, .0005 mfd. of met, explained In the right. Antenna Groan? /.r.W* C>idcn<<r V <»*KtU -V..,omtt«r V of the raw view of Mr. Schuck'* circuit, aa abowa hi tha lower at left. Tho bank-wtadiag eyrtem, Mr. Schuck believe*. ehouM bo welcome to all Thi* eeol.lag eet haa a true wave- length from US to MM meters. la a test of bringing ■» braadraatlng (tattoos, the results were aa foUowoi WJZ, WGI, WGY, WOR. WEAF. WVP, and KDKA— quite a atria*-. la coda station*, Mr. Schuch claim*, there la ao Kant to it* distance. It haa brought la eight district stations, dear a* a belL Its furtheet alrtancoo, ao far, are Station* NAO and NAP, located la Florida. Mr. Schuck'a station la fat Now York City. The Meaning of Potential By Harold Day THE word "voltage" has been used to indicate electrical pressure. Other terms are used, and it will help us in our understanding of electricity and in reading scientific books if we have some knowledge of these terms. We speak of an "electrical potential" and "difference of potential." "Differ- ence of potential" is the same as "voltage." Potential is the voltage (difference of potential) between any body and the earth. The earth is sn<~h a large body that its electrical <■ ' m is always con- stant. It is a fairly good conductor, and any loss, or excess, of electrons on its surface is quickly equalized. Thus we can use it as a reference point from which to make measurements. Its potential is always zero. "Potential" is to electricity what "level" is to water. The zero point for measuring water is, of course, the sea level. If one tank of water is 180 feet above sea level, and another tank 160 feet above sea level, their difference would be 20 feet. In other words, there would be a 20-foot head of water in order to make the water flow from one tank to the other. In this same way we speak of an object as having a potential of 180 volts compared with the earth. Another object may have a potential of 160 volts compared with the earth. Their difference in potential would be, as stated, 180 minus 160, or 20 volts. There would be 20 volts pressure to make the electrons flow from one object to the other. This difference in potential, or voltage, is known as electromotive force — Emf. GREAT ADVERTISING MEDIUM Radio Woixd's ipeciaJ issue, "Holiday Radio Gifts Number," issued on December 9. Cop* received up to November 29. Radio Wosxd. 1493 Broadway, New York. Digitized by Google

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RADIO WORLD 13 The Vacuum Tube Its Action and Proper Use. Correct Method of Caring For It By Donald Van JVyck TO understand the action of a vacuum tube it is necessary to know the following facts: A current of electricity is simply a flow of electrons. The electrons flow in one direction, forming a current which is said to flow in the opposite direction. Electrons are small charges of negative electricity. All materials contain electricity- positive and negative. It has been discovered that metals, if heated, will throw off into space some of the electrons which the metals contain; that the hotter the metal up to a certain degree of heat the more electrons it discharges. Electrons travel at a high rate of speed. If air or any other gas is present in the space around the metal the electrons strike the minute particles of the air, or gas, and are soon stopped. The above facts are applied to the vacuum tube. The air is pumped from the tube— hence the nime "vacuum"— so that the passage of the electrons will not be stopped. The filament marked F in a tube is heated so that it becomes red or white hot. This is usually done by an electric current furnished by a storage battery. G represents the grid, and P the plate. The vacuum tube is the only part of the more common radio receiving-set which requires replacement. It is therefore important that' the amateur have a correct understanding regard- ing its use. A detector, or amplifying tube, is nothing more than a highly evacuated incandescent lamp contain- ing a plate, grid, and filament. Thomas A. Edison made his first tube by in- serting a wire in the top of an ordinary electric-lamp. The principles which apply to the care of lighting lamps apply equally as well to the tubes. Only after scrapping a tube or two does the amateur realize that he has a delicate instrument with which to contend. It is certainly a delicate in- strument, for a very slight increase in filament current may prove fatal. The difficulty is introduced by the necessity of operating the tube so near its danger point. Very few people realize this. By a slight turn of the filament knob the fine tungsten-wire is brought to a glow, or, as we say, a brilliancy. The melting point of tungsten is 3350 degrees centigrade. This is higher than any other substance except car- bon. Iron melts at 1550 degrees centi- grade. Melting of the filament occurs when the battery is fully charged. When six or more volts are impressed across the terminals of the filament of the tube a rush of current passes to the filament, taking the chance of burning it out. To eliminate this some type of resistance is used in series with the filament and battery. Some of the more common type of vacuum tubes are designed and made to take less voltage. There are several types of rheostats which may be used with the vacuum tube. One of these types is the wire- wound rheostat. This has been widely used, but has many defects. Few amateurs understand its proper use. Sometimes when the broadcast doesn't seem to come in just loud enough he will force the rheostat up a peg or two. He does not realize that a very slight increase in current decreases the life of the tube, and the chances are that it will burn out. Another defect of the wire-wound rheostat is the method of bringing the filament to its proper operating-tem- perature. This is done by gradually increasing the current until it reaches the required luminosity. Contrary to popular conception, this is not the proper method of turning on a vacuum tube or any other tungsten-lamp. A tungsten-lamp should be turned on so How Mica Is Mined MICA for diaphragms comes almost exclusively from the Far East. India contributes the most of it, but some is mined in Africa. It is found far under the ground, frequently en- enclosed by granite or other hard rocks. When a mica rock is discovered, na- tives build a fire on it and continue it until the rock is thoroughly heated. Water is then thrown on the heated mass and the sudden temperature change opens up cracks along the "grain" of the rock. Crude wedges are then driven into these cracks and the rocks split apart. The pieces are loaded into native baskets and hauled and dragged to the surface. Only a small proportion of the mined mica is satisfactory for diaphragms. Sometimes less than one-tenth of one per cent, can be used. To be a success in reproducing sound waves the uvea sheets must pass laboratory tests for elasticity, toughness, resistance to heat, high electric strength and transparency Mica in itself is not magnetic, in fact its insulating properties are of a high order. To be successful as a diaphragm the mica must be aided by a flat disc of soft iron fastened firmly to the mica at the exact center spot over the magnets. chart abowlat *a «ra»b af a ■•Mary after tba tuba baa bam m aaaraMaa. Nate tba aWaraaca of tba battery raha«a aa caaaaaraa to tba bam* af aowar paaaaaaptlaa iniraai by Daaala Van Wyek. Dm by 5. Nawaua. that it instantly flashes to its operating temperature — but not above it I Burn- ing the lamp below this temperature causes the filament to crystallize and break when subjected to slight vibration. Tungsten, if examined under a microscope, would appear to the eye as a structure similar to a bundle of wires. Tungsten must have that structure in order to make it ductile and strong. Regarding the amplifier. If you will study investigations you will find page after page about the structure of tungsten and the intricate method of obtaining that ductile structure. You will learn also how the proper struc- ture is lost if the filament is used improperly. Heating the filament to a temperature of 200 degree* centi- grade below the' proper operating temperature changes the fiber struc- ture of the metal to a block structure. The filament, if examined under a high miscToscope, will look as if it con- tained a small train of cubes. The comparison is like the old story of the strength of a bundle of twigs com- pared to a single stick. Fortunately we need not worry about all of these changes in the tungsten in our ordinary lamps every time we turn on the light. The ques- tion is asked: "Could we use this same idea for lighting the vacuum tubes?" The problem is a little different The device used in the power-house - is expensive and bulky. But a more simple device is made which bids fair to fulfill the requirements of the radio novice, especially for radio work. The automatic current adjuster dampens the current when it tends to increase, and vice versa. It also per- mits flashing of the tubes to their proper operating temperature, thus causing the prevailing crystallization of the filament. In other words, it is designed to operate the tubes under proper conditions, irrespective of the condition of the battery or tubes.

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14 RADIO WORLD With the DX Night Owls From a Non-Radio- Frequency User EDITOR, Radio World: In Radio World, No. 31, dated October 28, I noticed a letter concerning an evening record of reception, by Mr. J. A. Merk- lein, 7513 Third avenue, Brooklyn, New York, in which his greatest distance was about 800 miles. I beg to submit for favorable com- parison the following record for one evening, most of which was made over an .Aeriola Senior set, using an aerial 196 feet, including lead-in, single wire, hung SO feet in the air, ground on water pipe. Part of this was made on a double circuit, regenerative tickler, using one-stage amplification. A home-made set. PWX, Havana, Cuba, 820 miles; then followed, in order, WLAG, Minneapolis, S2S miles; WGY, Schenectady, N. Y., 1,026 miles; WGI, Medford Hillside, Mass., 1,090 miles; and at 10.10 p. m., Central Time, I closed with station JCDYS, located at Great Falls, Montana, 1,667 miles. I have logged 54 stations, all over 250 miles from Birmingham, and would be glad to compare this record with any other amateur, who is not using radio-frequency. Come on you amateurs, step up and get your feet wet.— Kenneth F. Smith, 133 Francis St., Birmingham, Alabama. * ♦ * 16 Stations on 80 De- grees of Dial EDITOR Radio World: The records I have made in receiving no doubt have been equaled by others with half the radio or audio-amplification; but I doubt if many can equal what I am do- ing with one detector-tube without any amplification. I built my apparatus, and although I have two steps of audio-am- plification which I use with a loud- speaker when I wish to entertain friends, I have been experimenting for some time to see just what can be accomplished with one tube only. Many fans refuse to believe the results of my work, but I have proved it to others who have visited me. While experimenting on my home- made receiver, I have heard, in the past few months, concerts from over a hun- dred different stations located in 30 dif- ferent States of the Union, also Canada and Cuba, 2,250 miles air-line to Cali- fornia, 1,350 miles air-line to Denver, where I get two stations quite regularly. I have heard three stations in Texas- Dallas, Houston and Fort Worth— also WBPA regularly, about 1,150 miles air- line. I get PWX, Havana, Cuba, most every Wednesday and Saturday night, about 1,250 miles air-line. I get all southern and western stations regularly. All of this has been accomplished on a detector tube without amplification. I have even listened to WOC, Davenport, Iowa — about 575 miles air-line— without amplification or antenna. My apparatus is so finely adjusted that, on a test, (with others present) when weather conditions were good, I made the following record : In about 20 minutes time, I tuned 5 different stations at 400 meters, 5 dif- ferent stations at 360 meters and 6 sta- tions between 360 and 400 meters, clean and clear, without any interference. One would hardly think that stations sup- posed to be at 400 and 360 would vary that much ; but they do according to how I check them up. I got 400 meters at from 20 to 22 degrees, and 360 meters at 14 to 16 degrees, on the wave-length dial of my receiver. It is almost impos- sible to turn the dial sufiiciently by hand, so I use the rubber at the end of a lead pencil to lower the edge of the dial, by twisting the pencil. By this method, I can turn the dial to a hair. In this 16-station test, after the receiver was adjusted and set for reception of first station, all I had to change for the stations following was the wave-length dial or secondary condenser.^ Result: 16 stations on 80 degrees of dial. The foundation of my apparatus is the 3-circuit honeycomb-coil design with some important changes in various places. However, I get results. At present, I am the official eastern outpost testing station for WSB, Atlanta, Georgia, and we have been of mutual • benefit to each other. WSB is one of the best on the air and about the cor- rect distance — 550 miles air-line — for good testing. I have used their broad- casting for a standard to build a machine of which I am very proud.— H S. Ra- hiser, Box 43, Crafton Station, Pitts- burgh, Pa. • * » Something to Brag About 1 EDITOR, Radio World: The follow- J ing is of no small moment, and will be of interest to other radio fans, espe- cially those who have broadcast their success through your columns: I have an MR-6 De Forest, two stages of amplification, a Magnavox, 2-strand antenna 75 feet long and about 25 feet high. Thursday morning, November 9, I received a letter from Harry Davis, playing at the Lyric Theatre, Atlanta, Georgia, asking me to tune in at 400 meters for WBS, Atlanta "Journal/' Thursday night November 9, at 11.55, when there would be broadcast a mes- sage to me at my home in Hollis, Long Island, and that he would also warble a song for me. If I succeeded in tuning in for WBS the Atlanta "Journal" wanted me to take down the program and im- mediately telegraph them of my recep- tion. After playing around an hour with local high-powered stations and many long-distance stations, among which were Louisville, St. Louis, Chicago, Detroit, Cincinnati, Indianapolis, Daven- port, Milwaukee, Minneapolis, Pitts- burgh, Buffalo, Washington, Fort Worth, and many others, finally, at 12:05, I got WBS loud and distinct, but feared it was too late to receive the message that was to be broadcast to me. However, I hung on and, at 12:45 the message came, and the song followed, the program con- cluding at 1 :10 a. m. I immediately sent a night lettergram diagnosing the pro- gram and messages broadcast to Panama, Kansas City, and other places, as proof of my fine reception and, the following night, the result was broadcast by radio and published in the press. Saturday night, November 4, I re- ceived, loud and distinct, a program from PWX, Cuba. Have had several stations in Texas several times. My set is most sensitive. I have received the voice 3,000 miles and have had France and Germany on code. With the additions I am mak- ing, I fully expect to receive the human voice from across the ocean in the near future. One advantage I have, I am able to tune out all static. I did this dur- ing the summer. I am able to tune out all nearby high-powered stations for the reception of long-distance programs.— L. R. Ault, Seminole Avenue, Hollis, Long Island, New York. * * • Hears Denver in Maine EDITOR, Radio World: Sometime last May, I forget the exact date, a local amateur operating a Westinghouse R-C set picked up part of a concert broadcast from the Reynolds Radio Com- pany, Denver, Colorado. I consider this quite a record as the conditions were only normal and the transmitter was not of very high power. — Maxwell K. Mur- phy, 2 Orange Street, Eastport, Maine. ♦ * * DX without Antenna EDITOR, Radio World: I state here- with what I believe is a record for long-distance receiving, without using some form of antenna. On the evening of November 2 while listening to a fine number from WBAP, rendered by the Oil City Jazz Band, I had considerable interference and de- cided to close the station for the evening. Not thinking, I disconnected my an- tenna before cutting off the battery cir- cuit. I was somewhat surprised to find that WBAP's program then came in exceptionally good. This brought on some experimenting and I found that I could easily tune in stations WHB, KSB, WGM, and WBAP. On the evening of November 3, the experiment was repeated and I tuned in the following stations, WGM, WDAF, WWJ, KDKA, WSB, WHB, WOC, WHAS, KSB, and WOS. My set is a simple home-made affair with U-V 200 detector and two stages of audio-frequency amplification. This information is positive and I am ready at any time to produce my wit- nesses or repeat the experiment. In order to ascertain whether or not the set was in any way connected with the antenna, I disconnected all wires, moved the set ten feet from any outside wires and the results were the same. I would be glad to have your opinion on this matter, and will also be glad to hear from any other station that can duplicate the feat— E. M. Pace, 423 Far- mer Street, Vicksburg, Mississippi * * * A First-Night Record EDITOR, Radio World: With the hook-up suggested by Mr. W. Miller, as published in Radio World, I have re- ceived, very clearly, KDKA, WEAF, and all the Philadelphia stations. This has been accomplished with a hurried hook- up without soldered joints. Also, I have had no trouble tuning out stations from 360 to 400. I think that with using a vernier condenser, I will get much better results. I accomplished the above the first day I hooked-up, using only old material I had around.— R. L. Jones, jr, Lanerch, Pennsylvania. • • * On Detector and One-Step E DITOR, Radio World:— I have no- ticed Mr. Merkleins' claim of a record for receiving. On a detector and 1-step of my own make, I have received such stations as KDKA, Pittsburgh; Louisville, Kentucky; WOC, Daven- port, Iowa; the Sweeney Auto School, Kansas City, Missouri; KYW, Chicago; WSB, Atlanta, and, also, on October 29, at 10.30, I heard a station call letters ending with X, Havana, Cuba.— E. Gar- butt, 56 Clark Street, Stapleton, Staten Island, New York. Digitized by Google

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RADIO WORLD 15 f CFRONT be Ute with fom 'copy; for oar June of No- ««Ara," MoSt Elaborate RadlO- Equipped Vessel Afloat D vember 25th," the editor of Radio Wobld wrote me the other day, and as I looked at the date on his missive, I was somewhat startled. "That means that Christmas is only a month away," I said to myself. Only a month away— just thirty days more and the gladsome season with all its blessings and happy burdens will be at the peak of its celebration. And I must frankly admit that I haven't made a single thing— either with knitting needle or sewing machine — things that women usually start early in fall and seldom finish — and I am not worrying. • • • The popular slogan, "This is a radio Christmas," I have nailed to my door. There is going to be a big surprise in store for Friend Husband, however. Heretofore, I have given him cigars and neckties; but, this year, I intend to present him with a new radio set — because I want another set so very badly myself I When he sees it in his stocking, he will frown and say a few things under his breath; but when I explain that I need this new set because I am intending that my present layout shall be used exclusively in a little country bungalow we are fitting up for summer, he is going to be perfectly satis- fied and congratulate himself on having so clever a wife. » • * At any rate, I say to all mothers— and all fathers, toe— -if you do not know what to give your boys and girls this Christ- mas, do not overlook radio. Get them interested. It will keep them home. It will educate them. It will bring them the proper sort of friends. It will fascinate them. And a radio set is something that is not played with for a few days or weeks. It is something that one will grow more interested in as time passes — something one will want to improve and study and make a part of his very life. • * • I have already helped a number of mothers who are planning radio sets or parts as Christmas gifts— and I cheerfully offer my services to any others who may be in need of information regarding prices, just what to buy, the why and wherefore of different radio elements, why certain things are needed for certain sets — and so on. I have made a very thorough study of all things pertaining to radio, of all the different goods on the markets; and I have even read about every book on radio that has come from the press. So, I feel, I am in a position to help you this Christmas — and I offer my services cheerfully. • * a Whoever thought of the slogan. This is a radio Christmas," hit on a happy idea; but I would rather have said, "This is to be the first radio Christmas." You will find that the Christmas of 1923 and the Christmas of 1924 and every Christmas there- after will be even more radio in atmosphere. Next year will be more remarkable from a radio point of view than this year. And radio will continue to grow and grow until it becomes so much a part of our lives that we will not be without it under any circumstances. When grand opera and baseball and foot- ball and every big public event is as accessible by radio as it is through the daily press, only the people who are behind the times will be without it. • • • And I want to tell you all that I heard the broadcast of "Aida," by the Metropolitan Opera Company and orchestra. All I can say is that if I had shut my eyes, I would have imagined myself in the "golden horseshoe" of that favored place. The rendition lost none of its beauty coming over the ether. In fact, it seemed to me that it was particularly beauti- ful. Everything— from the deep diapason of the bass instru- ments to the thrills of the soprani and the birdlike notes of the flutes— came through with wonderful charm. A woman friend whom I had invited to tisten in, who had never heard a grand opera in her life, was thrilled almost to tears. She never could have afforded the price of an admission, and for the first time in her life, her deep-rooted love of music was partly satisfied. • * • Miss Mary T. Jackson, of New Orleans, writes me to advise her regarding C batteries for radio-frequency. After reading her letter carefully, I will ask her to read my answer herewith just as carefully. Do not interfere with the set that is giving you such good results unless it is to add another stage of radio-frequency. The 201 tubes should be used for the amplifying circuits and the 200 tube only in the detector. C batteries are not used in radio-frequency, as the job of putting a negative potential (C Ksdtl * Hcrbart. 1». Y.) Tkm 'An- ptor** bar part la Si by Mr. W. K. Vt It, of Haw Yarfc, is tfca alaaatati naW of eaat. That yacht. aa» ItarraaWtinnal on the grid of the amplifying tube is taken care of by the potentiometer across the A battery. In radio-frequency amplifi- cation there is no step-up ratio in the transformer. The pri- mary and secondary are of the same number of windings. The transformer merely passes along the amplified output of one tube to the next tube of the further amplification. a • • Whisper I The editors let me have a peek at the Christina cover for Radio Wosod. the other day. It is a beauty- and cheering and full of the radio-Christmas spirit, not miss it. The big Christmas number will be ber 9. Digitized by Google

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16 RADIO WORLD Latest News-P Week (C International Newi Keel) (Above) With bo provision mad* for tunimj, a receiving sat moat, perforce, ba of a lo order of affleiaBcy. Furthermore, all signals coma in at the same time, if several transmitters are working in the Immediate vicinity. Such raceivera are possible, but are never brought into practical use, due to the fact that they have no means at controlliaf wave-length. Usually the beginner starts off with an arrangement of this sort. In the accompanying illustration, a receiving set of this type is shown, built on a rubber beat It employs a detector, with outdoor antenna and water pine as ground. It was constructed by E. Johnson, of Minn—polls, Minnesota, at a coat of $1.3$, exclusive of the receiver. Mr. Johnson claims that be can receive with this make-up within a range of about ton miles. Kadel (C International News Reel) (Above) One of the most important elements in radio is the inductance coil and the trans- former. These instruments make It possible for us to hear the long-distance transmitting stations. Due to the many fine wires in the transformer, it is necessary that they be wound with absolute correctness. By hand would ba a tedious and tiresome Job. In the photograph, a machine is shown by which Miss Alma Stark winds the transformer or induc- tance coils. r> ■ spools of wire at the light of the machine. These spools of magnet wire are of -izes— one is of a coarse sire, which makes up the primary winding; the othc used on the secondary. Transformers, due to their peculiar wind- ing, m< ist care in their manufacture, as one error in winding will cause rmer to function in an unsatisfactory manner. (Above) Dr. Royal S. Copeland, who, on March 4, WX bi State Senator from New York, is a radio enthusiast. He U photograph giving his sob. Royal S. Copeland, Jr, a leu Digitized by Google

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RADIO WORLD 17 otos of a Busy n Radio (C Kadel & Herbert) (Abort) Rmmd Francis Duffy OT-anghUn, of Fordham University, New York, to om of the orixinal radio- fans of tho United States. Ho believes that the futnro of radio to unlimited. He early law the treat ponlbOiUee of the bow science and It to largely due la his efforts that Fordham University possesses so elaborate aad perfect a radio equipment. It was one of the first universities to use radio In broadcasting and receiving, particularly athletic events. During tha football season. It has proved that radio is the loog-looked-for necessity in dto- ating news of important games. The photograph shows Reverend CLaughttn at tho Fordham radio- receiving station. (Above) This photograph shows how phono- graph musk Is picked up and broadcast by microphone and broadcast. It is part of the radio equipment of station WJZ, Newark, New Jersey. This equipment, together with the skill of tho operators there, to respon- sible for the great distances It covers and the quality of its transmissions. This photo- graph shows operator George E. Oliver broad- casting a phonograph selection and gives a good idea Just how it is accomplished. The sound leaving the phonograph horn is picked up by tha microphone, then carrying it Into the modulator, shown on the right. From there is goes into the speech amplifier, shown on left of modulator, and thence to ti (C Kadel & HrrberO Usitsd • ■ the (Above) i eating the quality of loud speakers by means of the latest equipment, that photographs defects. To test the quality of loud speakers an elaborate layout of scientific apparatus to neces- sary. The photograph shows how this testing is done at Columbia University, New York. J. C A coves, research engineer, is testing the quality of various loud-speakers for manufacturers. The sounds produced by loud-speakers is picked up by the small special-type microphone shown, than tho microphone pasaas these sounds on to tho oscillograph, where these loud waves are photo- graphed. The slightest distortion or any other defects will bo shown. (Left) Fa at free radio school. The radio school of tho Knights of Columbus, New York, has over a hundred students, the majority of whom are ex- service men. Tho photograph shows one of the radio clsssos receiving Instruction in wiring a •Marconi receiver. The men are taught how to operate and build all forms of radio equipment.

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18 RADIO WORLD Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengths for the Busy Reader. OVER fifty atationa have qualified in the final tests be- tween this country and Great Britain beginning December 12. When reports from the outlying districts have been received over a hundred contestants will be enrolled. A number of stations have already been logged by British amateurs, con- firmation reports having been made on stations 2 HJ, Harold Hasbrouck, Port Chester, N. Y., and 2 ZK, George Cannon, New Rochelle, N. Y., and it is expected that many others will be confirmed. From the results obtained so far, and from the interest shown in the preliminaries, it is certain that the coming tests will comprise the greatest amateur event in radio. * * • A lighthouse station on the Maine coast reported to the district office by telephone that a large can buoy had broken adrift and was moving away. A radiogram was sent to the tender work- ing on buoys, a few miles away. The buoy was recovered and returned to its place before sunset. Radio saved the buoy and probably a day's steaming of the tender. It also safe- guarded shipping by promptly replacing the buoy on station. * • * Dr. Charles P. Steinmetz, research engineer of the General Electrical Company, running for engineer and surveyor of the State of New York, on the Socialist and Farmer-Labor tickets, polled a surprisingly large vote in the recent election. In the midst of a Democratic landslide, supposed to be unfavorable to "scratched" tickets, he polled 207,000 votes, 144,000 more than the candidate of his own party for governor. Dr. Steinmetz did not leave his laboratory to make a campaign. He spent no money. He lost the election, but the large number of votes he receij^d indicates the value placed by men and women on sheer aVa£ty. He is one of the most distinguished inventors, scientists, engineers and radioists in the world. * * * Dr. S. W. Stratton, for twenty-one years the director of the Bureau of Standards, has been elected president of the Massa- chusetts Institute of Technology, in Boston. This institution will give a four-year course in radio engineering, and is the first college in the country to inaugurate such a course in that branch of engineering. * * * WGY will tell the story of the Harvard. Yale game, at New Haven, by means of a telephone line running from the press section of the Yale bowl to the transmitting equipment of WGY. Mr. William McGeehan, sporting editor of "The New York Herald," will describe the game. You will hear his voice and his description will be literally on the heels of the runner, his voice will be on the ball as closely as the eyes of the players. In addition to the speaking microphone into which Mr. McGeehan will pour his story, one microphone will be placed in front of the Crimson cheering section and another in front of the blue. At intervals during the game, the cheer- ing section microphone circuits will be switched on and the radio audience will get the atmosphere of the big game. "The New York Herald" radio report* of the Harvard- Princeton, Yale-Princeton football games, as broadcast through the General Electric Company's WGY station, were heard clearly and greatly enjoyed by radio fans over a wide area in the East. The "Herald" received a number of congratulatory telegrams from a wide range of territory. The Brompton Pulp & Paper Co., Sherbrook, Quebec, wired : "Details of game very much appreciated." » * * Perfection of apparatus for insuring the secrecy of radiotele- phone and radiotelegraph messages was claimed recently for a French electrical engineer, Edouard Belin. The apparatus U called "radio-cryptotele-stereographe," or "cryto-telestereo- graphe," according to whether it is used for radio or the or- dinary telegraph. The instrument is different from Marconi's to direct waves to a given point. It resembles a safety-lock. Sending and receiving instruments, each of which consists of six concentric disks, are perfectly synchronized. The disks each contain a notch and may be moved at an angle in relation to each other. A lever falling into the disks causes rotation of the cylinder and valves a given space between the notches to reproduce the message, which is received according to a code analogous to Morse's, but is reproduced in letters and figures. To keep listeners-in from deciphering the values used between stations, a simple arrangement is added whereby false signals, which do not affect the cylinders, but which cannot be distinguished by outsiders from real messages, are being con- stantly sent when the instrument is not in use. * * * The Chicago Opera Company has decided to broadcast its productions. * * * » Leading scientists of Norway propose to install a series of radio observation stations around the North Pole so that the air currents from the polar regions may be followed and the centres of conflict with the warm southern currents deter- mined. Such polar outposts would be of great importance when a regular daily weather forecast becomes necessary for the North Atlantic in connection with aviation service from Europe and America. * * * Radio messages were sent by automatic machinery •* a rate of between 80 and 100 word* a minute by the White Star liner Majestic to the station of the Radio Corporation of America, at Chatham, Massachusetts. This speed is about four times as fast as ordinary operators can send and receive, while the greatest speed made by the most expert senders is about thirty-five words a minute. . The speed is nearly as fast as that at which mes- sages may be sent by wire, and may open a vast new field for usefulness. The value of radio in handling transcontinental and transatlantic news has been reduced by the slow pace at which messages could be sent, but this new device, it is ex- pected, will obviate this. Radio's Big Place in World Dr. Lee De Forest Says It Is Now an Absolute Necessity in the Home. ALL radio enthusiasts may well take pride in the fact that the present tendency in the radio field is away from the amateur experimental stage," said Dr. Lee De Forest in his greeting to the Boston Radio Exposition. "The reason for this is plain. In the short period of less than one year since radio has taken hold of the American public, we have seen a most remarkable acceptance of radio as a means of communication. This acceptance on the part of the Amer- ican public is nothing short of marvel- ous. Science has again demonstrated in radio that it can perform miracles for the benefit of the human race. "Radio has enriched the lives of count- less thousands who are not in a position to attend concerts and operas in the leading centers of the country. Radio, however, has gone far beyond the prov- ince of the amusement stage and will, I venture to say, go down in history as one of the few revolutionary devices bringing happiness and joy to countless millions in the way of educational in- struction, entertainment and as a means of distributing the news of the world to the people in their home." Marvelous Developments Include Radio Navy Communication Service Handled 3,750,000 Words by Radio Last Year. AERONAUTICS and the radiotele- phone are, perhaps, the most marvelous developments of a marvelous age," said Rear Admiral William A. Moffett, chief of the Naval Bureau of Aeronautics, U. S. N., speaking over the radiophone from NAA, Arlington. Admiral R. E. Coontz, chief of oper- ations, who broadcast a speech in the interests of the Marine Exposition in New York, said that among its activities the Navy Communication Service handled 3,750,000 words by radio for the American Merchant Marine in the past year. "During the winter months," he said, "the Naval Communication Service handles on an average of thirty SOS distress calls a month, or one a day." That the value of this service to the American public as a whole, and to ship- ping interests in particular, cannot be over-estimated, he insisted. He also mentioned the developments of the radio compass, or direction finder, and stated that the Navy has established stations equipped with this apparatus at various points along both coasts of the United States near the entrance to har- bors. When a ship is approaching one of these harbors in a dense fog and is uncertain of her position, all that is necessary for her now to do is to ask two or more radio compass stations for her bearings. Digitized by Google

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RADIO WORLD 19 Latest Radio Patents Fie}. I Figure 1 b hi obverlnn of a complete grid •lac- trod* of the invention of Mr. John H. Paynes Flfura 2 U an enlarged perspective on ana and tfcaraof; Figure 1 la a etm further aniargad detail tW of a email portico; Figaro 4 la a datafl view Grid Electrode Structure No. I^Mll. Patented* October IT, US. Pa- ri, Payne, Schaaactaay. N. T. MR. PAYNE'S invention is, in simple terms, a structure for a grid electrode made of a large number of turns of wire of small diameter which will be self-sup- porting, and which will be so arranged that adjacent turns of the wire will be maintained in desired spaced relation to one another. In such a structure there will be no necessity for welded joints between the different ele- ments for maintaining them in their proper spaced relation. a a a Radiotelegraph Coupling No. MSI/OS. Patantadt October IT, ISO. Pa- tentees Joeeph Bothonod, Parte, Franca. MR. BETHENOiyS invention relates to an improved system of coupling be- tween radiotelegraphic communication and a high-frequency alternating-current generator of the type of those susceptible of furnish- ing directly a current necessary for feeding the antenna. This station comprises in com- bination a high-frequency alternator in which the armature winding is divided into sev- eral Sections not comprising any direct electric-connection between them, and a com- plex of transformers magnetically indepen- dent of one another; the number of trans- formers being equal to that of the sections of the armature. The primary windings of the transformers are inserted in series in a circuit alternately with the sections of the armature, and the secondary windings of these transformers are connected to the trans- mitting antenna in a suitable manner, a » » To Increase Discharge No. MBJST. Patented, October 24. Its. Patentee, Marvin J. Rally, New York, N. V. ^^R. KELLY'S invention is to increase the amount of power which may be applied to an electron discharge device while still keeping within the safe limits of temperature under which the electrodes can function ; to eliminate the objectionable effect which is sometimes . produced in electron- discharge devices, namely "blocking," which is caused partly, at least, by undesirable sec- ondary emission from the grid ; and to elimi- nate the effects upon the operation of 1 Mr. Kenya evacuated bulb to which the la attached. Thia • preferably electron discharge devices which the lodge- ment of particles of the filament coating upon the grid have caused. An important feature of this invention comprises the provision of a black coating on the electrodes of electron-discharge devices, particularly the plate and grid. Electron discharge devices have been de- ficient in their operation in one respect be- cause only a limited amount of power could be handled by them without heating the electrodes beyond a safe temperature. By increasing the capacity of the electrodes to radiate heat faster, we can increase the power applied and still keep the temperature within safe limits. 1 I c • II » r "OheRepmducerStipKmi MAGNAVOX products are designed in our own lab- oratories and manufactured in our own factory — greatly ex- tended in size during the past few months. The Magnavox Power Amplifier has been designed for use especially in connection with the Magnavox Radio, and its use greatly increases your range and signal strength. Every owner of a Magnavox Radio should 'also add the Pc r Amplifier Model C if he has n • already done so. R-2 Magnavox Radio with 28-inch Horn FOR those who wish the ut- most in .amplifying power; for large audiences, dance halls, etc. Requires only .6 of an am- pere for the field. Price, $85.00 Type R-3 Magnavox Radio with 24-inch Horn THE same in principle and construction throughout as Type R-2, and is ideal for use in homes, offices, amateur sta- tions, etc. $45.00 Magnavox Power Amplifier Model C INSURES getting the largest possible power input for the Magnavox Radio. Can be used with any "B" battery voltage which the power tube may re- quire for best amplification. AC-2-C, Z-Stata. $80.00 AC-3-C, 3-Staf*. 1 10.00 U Hod of good temlm The Magnavox Company New Fork Office : S7t Seventh Am ^i'dU&brings it MAGNAVOXm* Digitized by

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20 RADIO WORLD Answer to Readers CAN a small dry-cell tube be used as oh amplifier. If so, will the regular am- plifying-transformer function with itt Can such a tube be used in the Armstrong super circuit ?— Joseph Mulacaha, Omaha, Neb. This tube is called the aeriotron dry-cell vacuum tube and may be used as an audio- frequency amplifier; but it cannot be used with radio-frequency or the Armstrong super circuit. In employing this tube for audio-frequency amplification, the regular standard amplifying transformers may be employed. This tube will stand up under a plate voltage of 45 volts. Its filament oper- ates on a single dry-cell, such as is used in an ordinary door-bell. * • * In a two-wire antenna, how far apart should wires be separated by the spreaders at each end Are they joined at each end or only at the lead-in end? Can radio- or audio-transformers be put into a crystal cir- cuit with satisfactory results?— Jacob Murt, Bayonne, N. J. About two or three feet is the correct spacing for the wires. They should be joined only at the lead-in. Radio- or audio- frequency amplifying transformers are use- less in a crystal circuit * * * What is the best pair of phones to.be had at a price not exceeding ten dollars? Can a pair of 2,000-oAm phones be used with any set?— Albert Murphy, Philadelphia. It is impossible for this department to discuss the relative merit of the various competitive makes of radio instruments. * • * /* a loop aerial ail right for a ,-rystal set? Will it prevent interference? Which con- denser is best for receiving, Ai-plate or 23- plate?— Arthur Horn, Philadelphia. The loop antenna will not give satisfac- tory results on a crystal set unless the *et is located near a broadcasting station. Loop ■ aerials, when used with vacuum tubes, have the marked advantage of eliminating inter- ference. Either the 43-plate or the 23-plate condenser may be used, although the latter will permit of finer tuning. The 43-plate condenser has the greater capacity. * * • Will you advise me what to do with my variometer set? I cannot get any signals, only a lot of screeching and howling. En- closed you will find my hook-up? — Anxious. The only change that may be suggested is to place the rheostat in the positive side of the A battery and join both negatives of the A and B batteries to the return lead from the secondary of the vario-coupler. In order to make this change, all that is neces- sary is to simply change the connections of your storage battery, leaving the set wired as it is. Tf you have the set wired up, ex- actly, according to your diagram, with this one exception, there is no reason why you should not hear signals. Are you sure you have the positive terminal of the "B" battery jointed to the plate of the vacuum tube? * • • // f the loop is then obtained by means of varying the '■on- denser, which is placed across the loop and the vario-coupler; and, also, if necessary, by placing the attaching clip on the lead at different points along the outside wire. • * * /* a loop aerial all right for a crystal set? WUl it tend to prevent interference? Which condenser is best for receiving sets — the 43- plate or the 23-plate?— Kenneth Kiefer, Mineola, L. I. The loop antenna will not give satisfac- tory results on a set employing the crystal, unless you are very close to a broadcasting station. The loop antenna will eliminate much of the interference. Either the 43- plate or the 23-plate may be used, although the latter will permit fine tuning when placed across secondary of vario-coupler. The 43-plate is used in series with antenna. ♦ * • / wish to construct a crystal receiving set employing a double-slide tuning coil, a vari- able condenser in the aerial lead-in with a fixed phone-condenser. It is desirable that the coil be as shori as possible, but long enough to insure the eception of 400 meters. Assuming a properly installed aerial, 100 feet long with a 30-foot lead-in, what should be the diameter of the coil and how long the winding? Would a coil wound on a solid wooden block be as efficient as one wound on the regulation cardboard tube? If so, would a coil wound on a flat wooden block of equal circumference be equally as effi- cient?—John Matthews. Huntington, N. Y. Your coil should be about 2& inches in diameter and wound for 3 inches of its length with No. 22 wire. A solid core is not as efficient as a hollow core, as solid cores cause dielectric losses. A coil is almost efficient when it is round and, therefore, a flat wooden block is much less efficient than a round one. ♦ * * • /* it Possible to use a very small coil with a. -condenser to increase its wave length? Why is this not done more frequently? — George F. Rye, New Bedford. Mass. In receiving work, it is advisable to have a preponderance of indu* mce. as a maxi- mum of efficiency is "ihtained when the yoltaee is greatest ; and the greatest voltnsre is obtained across a coil ralher than .icroM a conden«er. Therefore, it is advisable to use as little capacity as possible. Digitized by Google

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RADIO WORLD The HOMCHARGER AUTO or RADIO BATTERY br a NWwI. Prim. SIS.S* Sao* lar rill Balktla DEALERS— WRITE MOW I Tin Automatic Electrical Drrlceo Co. Wnt Tattd St.. Ola.. 0. SPECIAL OFFER For a limited rJaaa only RA-1S....SSS Grebe CR-S.....' DA-2 ....H Crobo RORK... PrUaa F.O.B. Ro* iuk, N. J. A. V. GREGORY ■in N. J. PHANTOM-CIRCUIT BUILD TOO* OWN. Thla nana! at aa aarlaL no loap. a> fmiad. brum la awnt laataad of uda •Mm W. ■onaUuoHi bow aaaaarta «a Minim, fraoi ataUana tit alba dlataat. aodlhta 1*0 Com froo ham. Tb> OnpUaltT oT IhU art wUI aarprtaa rot No radio fraqoaaaj. Ooaptot* laatroa- ttaaa with photo at etroult ant propaM tor taa. VESOO RADIO SHOP. 8a W-7S4, Vaor/IHa. Oil If. Variometer* with dial, $2-38 Variocouplera with dial, IMS Pot* Paid Money Back if not Satisfactory OSLAND, INC IB FIFTH AV. NEW YORK ALADDIN ELECTRIC COMPANY, INC COMPLETE RADIO SETS WHITE FOR PRICES. • Wot* Broadway. Now York City PATENT PENDING TVa NiMaat Short War. Timor on tko Maria* Oar, PM* A PP on 1 lb. Seed far paamblet L. W. GOODMAN D REX EL HILL, PA. Malar rrr, HalHaa. N. »-. orHaa: DaRakML ftrMae'aooDai MO, New Radio Craft Teat of New Radio- Equipped Naval -Spotting' PUne Made At Cleveland. ANEW Naval "spotting" plane equipped with a recently perfected radiotelegraph set was tested officially before a board of Naval officers at Cleveland, Ohio, November 15. The plane is a three-seater, designed for ob- serving and reporting to ships in ac- tion the fall of shells and their distance from the enemy ship or target. It is the first of several newly developed spotting planes designed for Naval work and was built by the Glenn Martin Company. One of the most important features of the "MO," as the craft is designated, is its radio equipment, which is said to es- pecially meet the requirements of in- stantaneous and constant communica- tion by radiotelegraph between the spotters and the flagship, where the fleet gunnery officers and the admiral control the fire, or to individual ship's gunnery officers if the fire is controlled separately. Only general information regarding the Navy's spotting radio sets is avail- able, but it is known that the sets so designated are modern tube telegraph sets operating on continuous wave, and having excellent characteristics for range and reliability. They are especially rugged in their construction and guar- anteed to "stand up" better than the or- dinary radioplane sets. Power and range are withheld, but it is understood that they will transmit 300 or 400 miles. Sat- isfactory communication is assured, even though a great number of planes are sending messages at the same time. The power is generated by a wind- driven generator with a self-regulatory fan giving constant revolutions at all air speeds, so as to iurnish the tubes with a steady voltage. Progress in Electricity From Data Compiled by the Society for Electrical Development Generating Capacity op Central Stations Year Horsepower 1902 4,000,000 1907 9,000.000 1912 17.000.000 1917 30.000.000 1920 47,000,000 Central Station Revenue 1914 $336,980,000 1915 360.000.000 1916 436.000,000 1917 526486.406 1918 664 £50.000 1919 773,650,000 1920 922,300.000 1921 931,000,000 FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Plmui tend me RADIO WORLD for pj«tt*f and enclosed $ SUBSCRIPTION RATES: Coop 4JI 1493 BroUmmj, New Far* City. oeeeeeeeaeoeee 9t4sr1t$fatf (PrMefew On* Tear OB beam). Add OAS a Year tor American RADIO Exposition The Official Exposition for American Manufacturers with the endorsement of the NATIONAL RADIO CHAMBER of COMMERCE and sanction of the Radio Apparatus Section of the ASSOCIATED MANUFACTURERS of ELECTRICAL SUPPLIES Grand Central Palace New York December 21st to 30th (Sunday oxcoptrd but Ckrittmat Day included) This first really comprehensive Exposition to be staged in a manner worthy of a great in- dustry includes such represen- tative exhibitors as : Radio Corporattaa of Aa Kattoowl Carbon Compear C. BraaeVa, lac. mo In to Compear RxoeetlTo Radio Caswell Cote-Cell Compenf Woatoa Raartrtrel laatiaaaaal Co. Aawrlraa Radio Rotor I sages Itombon-Carlma at fa;. Co. HoHaor-Cahol Co Tateeaeao * Tele- All of the above and other lead- ing manufacturers have con- tracted for space and many more are at present negotiat- ing for representation. The opportunity to display Radio products to thousands of buy- ers during the holiday season is an unusual one. The expo- sition will be one of New York's big features in connec- tion with National Radio Week. For further particulars trite or u ire AMERICAN RADIO EXPOSITION COMPANY 1S« BROADWAY. NEW TORE TI1IPIOXI JOHN esss Digitized by Google

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22 RADIO WORLD AirertUkf Rates, Disptoy, $5.00 per tack, $19000 per page Radio Merchandising Oassiaea Qvick-ActMa Adrertumg , 5 cmUfr vwi Telephone Mrysmt 4796 Coming Events The estttsrs af RADIO WORLD wB PMtrf by publish Hwt It— aa sf all lUwi and axpaaltloaa. Keep aa Mil In* rail inform* tie*. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Cot, Chicago, January 13 to 30, inclusive, ISO, George A. King, director of publicity, 417 South Dearborn Street, Chicago, QL PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial. New York City. Opaa ires September, 1922, to May, lfSJ. AMERICAN RADIO EXPOSITION. Grand Cen- tral Palace, New York City. Decent bar 21 to JL Col well ■ Korbell, Flak Buildiaf, New York City, director! of publicity. INTERNATIONAL RADIO SHOW. Kadiaaa Square Garden, New York City, November 20 to 29, induaivo. B. C Buchiguani, director «f pub- Ueity. SOUTHEASTERN RADIO EXPOSITION, Audi- torium Armory, Atlanta, Georgia, December 4 to 9. inclusive. Co-e Peach tree St. i-eoerative Radio Salaa Aesa., 2M SECOND DISTRICT RADIO CONVENTION, Hotel Pennsylvania, New York City, March 1, 2, and 3, 1923. A Loud-Speaker Crystal Set rpHE Steinmetz Wireleaa Manufacturing Co., of * Pittsburgh, claims to have perfected an ampli- fier for crystal receiving sets which possesses tbe added advantage of requiring no storage battery. This amplifier may be used on any crystal act. It is sold in convenient units so that one, two, xx three stages of amplification may be added when necessary. These units uae a "peanut" tube requiring only a single dry-cell instead of the usual storage battery. To insure against interruption in the operation ■due to cat's whisker not being on sensitive point, the manufacturer provides an ultrasensitive crys- tal which, he claims, makes interruption almost impossible. • • • Eisemann Magneto Line 'pHE Eisemann Magneto Corporation announces *■ a line of radio parte designed to suit the most critical. Each part has points of originality that separate it from all other products now on the market Ready for delivery are vario- couplers, variometers, variable condensers with vernier, audio-transformers, sockets, and phones, each made to the highest standards. A feature of the panel parts is the concave bridge-dial which eliminates all protruding knobs, and acts aa a shield. Switch points and levers are eliminated with the vario-counler. All molded parts are of genuine bakelite highly polished. This line may be had through Clark 4 Tilson, 1 East 42nd street, New York Oty, who are pre- pared to supply descriptive matter for each part The prestige of the Eisemann Magneto Corpora- tion is guarantee that its articles are the standard .of quality. Outcasts! THE radio manufacturer of lesser magnitude who would succeed should advertise— after he has assured himself that he has a product worth ad- vertising, says The Mail," New York. The last two months of merchandising experience has shown that the buying public is insisting upon the products of the better known manufacturers. The prod- uct without a name is rapidly becoming as* outcast. All of the big department stores are carrying only apparatus that has established itself in the mind of the •public This is a very healthy indication. It shows that the radio industry is fast reaching rock bottom. It is actually starting to gather the prestige that it deserves. In another six months' time, many of its ills and sores will be cured. During the past few months, capital has flowed out of the radio field almost as fast as it flowed in last spring. That is also a good indication, for the get-rich- quick artists have been shown that radio is more than a match for their wits. U. of I. Gets Busy THE University of Illinois has opened its fall season with broadcasts on Monday and Thursday nights from 8.30 to 9.15. Its station, WRM, is operated by the electric engineering department. New Firms and Corpora- ' tions (The firms mid corporations mentioned m these columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Wilmac Electric Corp., Queens, $5,000; J. J. Mc- Farlane, Mr. Williams, A. Schichowsky. (Attor- ney, M. Friedberg, 116 Nassau St., New York.) Fremont Radio Sales Co., Manhattan, $5,000; E. and S. and H. Nagker. (Attorney, J. D. Nuss- baum, 84 Rivington St., New York.V Educational Radio Corp., Del., 3,000 shares com- mon stock, no par value. (Representative, D. Freeman, 342 Madison Ave., New York.) Let Radio World Test Your Goods MANUFACTURERS, send a sample of your goods to our Techanical Editor, Fred Charles Ehlert, MM Pleasant Street, Queens, Long Island, New York. It will be carefully tested. If your goods satisfy our experts, RADIO WORLD'S endorsement will be published in our merchandise department without charge or obligation of any land on your part. When the radio pur- chaser sees a published test in RADIO WORLD with the seal accompanying this editorial attached, he will know that the prod- uct stands for perfection and has the guarantee of RADIO WORLD. RADIO WORLD is rendering a service through its testing department that is prompt, accurate and produces results. All goods will be returned to manufacturers, after testing, pro- vided stamps are sent for that purpose. If Remember "This Is a Radio Christmas and that millions of dollars will be spent during the holiday time for radio gifts. Be sure to get your share of this business by advertising in the issue of RADIO WORLD of December 9, which will be RADIO WORLD'S CHRISTMAS NUMBER Thru this medium you can reach thousands of readers, who are not only interested in radio themselves, and want new equipment, but who also will give presents to others whom they wish to make radio fans. ADVERTISING RATES: Regular advertising rates in force for RADIO WORLD'S HOLIDAY RADIO GIFT (CHRISTMAS) NUMBER, as follows: S150 a page, $5 an Inch. Discount, 10% four times, 15% thirteen times. Last form closes November 30, A. M. Take advantage not only of RADIO WORLD'S circulation, but also its cash-thru-the-mail pulling power. Be represented in RADIO WORLD'S Holiday Radio Gift Number, and reach the many thousands who actually want your goods and are ready and willing to pay for them. Preferred Positions Must Be Booked Immediately 4 Copy for run-of-paper position will be received up to November 30, A. M. RADIO WORLD, 1493 Broadway. New York Digitized by

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RADIO WORLD 23 My Emergency Radio Receiver at 2 AAR By George Steier 2AAR, 584 East 139th Street, The Bronx, New York, N. Y. I Mr. Stater'* receiver employ* a new circuit de- signed after careful research— a crystal detector mounted Inside and adjusted by a set screw at the bottom. Its wave length Is from 1M to 7M meter*. The selective tuning 1* by mean* of a IS- point switch. The actual size of the re- ceiver is S inch** by 2 inches. HOW many times during a year are radio amateurs using tube sets, forced to give their phones or loud-speaker an involuntary rest due to a rundown battery. The writer, be- ing no exception, found it annoying to shut down for a few days and determined that an emergency set that required no "juice" was the necessary thing. But, alas, no spare space was available for a rather cumbersome crystal set. The writer began a battle of wits with his radio knowledge, arid, after some re- search work, designed the set shown in the accompanying photograph which re- quires the small space of 3 inches by 2 inches. A number of pocket, or small, receiv- ing sets have been described from time to time. I make no claim to first honors. However, most of these sets are of a freakish nature, more or less. My emergency set may be depended on dur- ing all sorts of trying weather conditions. The circuit employed is one of my own and was especially designed for long-dis- ln response to RADIO WORLD'S request for any in teres tins' con- structive work in ra- dio that might have been perfected by H* readers, Mr. George Steier, SS4 East Utth street. The Bronx, New York, sends the follow- ing- account of an emergency receiving set which, he claims, may he depended on in all sorts of weather. I tance reception. As a broadcasting re- ceiver, the results equal that of a one- bulb set. WGY, Schenectady, and a host of other stations at quite a distance are heard every night. The set has had a more or less inter- esting career, having been adjudged the second best receiver for use by the New York City Police Department. In a pocket-receiver contest of over sixty en- trants, this receiver was nosed out of first place by the small margin of five points. It was considered by the judges a most ingenious piece of radio work. The set is, also, very satisfactory, for amateur reception. Government sta- tions on 600 meters can be heard pound- ing in, five feet from the phones. Brooklyn Man Wins Code Honors J. C Smyth, 2 CKJB, Declared World'* Champion After Taking Three) Contests. JOSEPH C. SMYTH, 2 CKB, 269 Eighty-Sixth Street, Brooklyn, holds the World's radio championship. The title was awarded him at the New Eng- land Amateur Convention held at Boston. Competing against Mr. Smyth were Theodore R. McElroy, former world's champion, and Walter Vetromile, both of Boston. There were three separate code contests: "jamming," cipher code, and straight press, the stipulation being that the contestant showing to best ad- vantage in the three contests would be The pocket radio-receiving eat hv* George Steier (shown at left) compan (shown at right), m the ted by with a Free Radio Instruction at Mass. Inst, of Tech. THE Massachusettes Institute of Tech- nology, Cambridge, offers a free course in radio to extension students, this winter. The first care of this elementary course will be to give students an idea of what really constitutes radio and to supply the necessary theory for the intelligent handling of a receiving set. No previous knowledge of electricity is required. Classes are held at 7.30 p. m., in room 27S of Tech Building No. 10, on Tuesdays and Thursdays. M. T. Dow and E. L. Bowles, both of the Institute, are instructors. Show Will Be Exclusively for Fans THE Council of the Second Radio Dis- trict has decided that the annual .show to be held next year, (March 1, 2, and 3) at Hotel Pennsylvania tentatively, will be open exclusively for amateurs. Tim re- striction has been made, it is said, be- cause at the show held at the same hotel last year, the crowds were so large that radio amateurs were prevented from ap- proaching the exhibition booths to see what manufacturers had to display. V f 2* V • EE £ ft* (C Sport-Commercial) c. awarded the silver cup and the title; Mr. Smyth won all three. In the jamming contest two trans- mitters were sending simultaneously into the phones, and the contestants were re- quired to ignore the signals from one transmitter, and copy the other, a rather difficult assignment. Mr. Smyth won this at a speed of thirty-five words per minute without error. The cipher code consisted of ten-letter code words secretly prepared, and trans- mitted by a Wheatstone transmitter. This contest was won by Mr. Smyth who again made a perfect copy and broke the world's record for speed in cipher- code receiving by copying the difficult words at a speed of forty-four words per minute. The straight-press contest presented the closest race of all, as both Smyth and McElroy made perfect copies at a speed of forty-five words per minute, and again at a speed of fifty words. However, at fifty-five words per min- ute McElroy made six errors, while Smyth made five, thereby winning the world's title in all three. FANS, AMATEURS, DEALERS, BROADCASTERS, MANUFACTURERS, AND THE GENERAL PUBLIC Are Looking Forward to NATIONAL RADIO WEEK DECEMBER 23 TO 30, INCLUSIVE All Interested in Radio Should Help to Make This Event a Smashing S access. If you want to know more about H addreest NATIONAL RADIO WEEK EXECUTIVE COMMITTEE J. ANDREW WHITE, Chairman 321 BROADWAY NEW YORK Digitized by Google

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RADIO WORLD AGENTS Our established quality rewards your effort with liberal commissions even on large order*. ■Triple-test" multlmount crystale and "Triple- tone" apeclal gold alloy cat-whlekere are today the beet eellere to jobbera and retailers. High priced but unequaled In quality and aalea help*. Repeat ordera assured. State territory you want. FOOTS MINERAL CO., Inc., 107 N. lBth Street Philadelphia, Pa. Established 41 yean Did yon see our ad in RADIO WORLD of Nor. 18, Page 277 Watch for future announcements. mm P»DIO EQUIPMENT MFO. CO Deft "B." IIU JEROME AVE. NEW YORK. N. V. IS YOUR TELEPHONE HEAD SET WEAK? Let m»remagnet- J*-| ,50 fee it Guaranteed, v I bone day goods* * new. Per »st 1 rewind for higher ohmsf*. All radio telephone repairing af mod- orate prices. Mall orders attended to. Deal an write. ROYS, 101 West 42nd St, N.Y. Thordarson JQ.25 Transformers w Dictograph Phones, 3000 Ohms, $8.00 Value $6-5° Special Amateurs:— We Pay Postage. Perfection Radio Corp. of America 1« West 23d Street New York City Subscribe for RADIO WORLD. $M0 a year, $3.00 six months, $1.50 three months. RADIO WORLD TBLUFBOSTU. BBTAHT «tm JSHBD BTBBT WSSJW— DAT batcbdat or bamb wbmkj raoM ursucATMW otticm. 1411 SBOADWAT. WW TOsUL W. »._ BT HBrnrBBBT BAD 10 PfTBUOAnOMS OOBPOBATKW SOLANS BUBJEB A "A i a CLABk. nOLAXD BUBKB _ IMS Bneowaj. Its* Tors r*JK> a CLABX.Mis.rsr 141* Bissdwsy. How Tars ASBOOIATa XDITOaSl 81 B8CBJFTION KATBSl ADTKRTTBENO KATXSl Oas pass: Oas Sen HM.SS. Halt. Ojsaitsf. fstsS sad V Btspurttsssl rstss. One task, ess SSW-SS.M. V !».«*. St say* Kst. «* IS CLASBITtKD ADTXBTISXMKKTS I jsmim- jess* uL^.*" Baton* ss soosad el— msast. Msras IS. MM. st taeFest OSIss st Nss TsnX Ms* TsBX «**■ ttVsrt et Man* S. ISTS. IMPORTANT NOTICatt STJLsal^SfJe. ssssrtsi ».«* Ssld. sad seen use pruned Is tsss see* elta ase siislssi Msard to Ik* rests, tas gslsbst esslslas » say en Cast New Broadcasting Map *-pHE Radio Section of the Depart- l ment of Commerce has found it necessary to use a larger broadcasting map, the old one having become too small for practical use in locating the 564 broadcasting stations now in existence. The new map, which is 5 by 7 feet in size, is divided into radio districts, and each station is located in its approxi- mate position. The Difference Between Audio- and Radio- Frequency WHAT is the distinction between "audio" and "radio" frequency amplification? ask Howard Allen Dun- can in "The Globe," New York. And Mr. Duncan replies: The first is named "audio" frequency because it amplifies .oscillations that vibrate within audible limits. This limit is usually reckoned to be between 16 and 20,000, this last being the upper limit for the human ear. For radio frequency, however, the oscil- lations may vibrate hundreds of thou- sands and even millions of times per second, and the detector must bring them down to audible limits, so that they will actuate the telephone receivers, or other recording devices connected in the circuit. Radio- and audio-frequency amplifica- tions are entirely distinctive, and they both fulfil different and separate func- tions. One cannot take the place of the other, and one may not produce the same results as the other. Radio-frequency amplifiers should not be used to obtain loud signals, or when it is desired to have volume. This work will be better peoformed by the audio- frequency amplifier. However, when it is desired or necessary to amplify weak signals, so that they can be made to actuate the detector, the radio ampli- fier is the one used. In distinction to the audio-frequency amplifier, which is hooked on after the detector in the receiving circuit, the radio-frequency amplifier comes first, and then is followed by the detector. This is an advantage, for it permits the use of any type of rectifier, and allows the addi- tion of audio-frequency amplifiers after the detector, so that the amplified sig- nals can be made still louder by its means. , Thus, radio-frequency amplification magnifies signals so that they are much stronger when they reach the detector. This has the same effect as though the transmitting station were moved much nearer the receiving set. Any number of amplifying radio frequency steps, or stages can be used in a receiving circuit. There is, of course, a practical limit, and that is considered to be about four stages, for beyond that point the operation of the set becomes so critical and unstable as to make it difficult to tune it and get good results. HIGH GRADE CABINET Do not bo deeeived by oar prleee. m* nts — they a) the market LOUD SPEAKERS SPIROLAS sr» sit eheep Inttra. - ilsle by trrtlsvsntlss cabinet type, cabinet — extreme eempaetssM for jSjssjjjjp, elimination »( sjsMjjjj tnll.slnd tsss chamber snd really SPIROLAS sr* msds far musle Kjn .ho appelate pjj***; ?™;,|?WJ.5E. •Mstrsrll.s terwiaeut. with See. (DM) flnUh. bronzed threat $3.85 ask (SO) er ashssssy (8*1) Osns, bronzed ureal $3.85 Mir? w*ttbi!!*r5r.«8^ *iM icv 67 b; it L H. DON^TL MFG. CO., Dept B, Box 70, Ann Arbor, Mich. tonal Radio Week Booster! Argentina Organizing in Radio ARGENTINA has just organized a radio association in the City of Ros- ario, with forty members, according to a report from Consul Bonney, to the Department of Commerce. The organ- ization intends to obtain board-of-trade quotations from Buenos Aires by radio. Adolfo Elias, J. Torres, Lorenzo Aguerre- berry, Alfredo Muzzio, C. J. Todman and G. O. Caesar are the organizing commit- tee. Experimental receiving radio sets are made in Rosario by C. E. Smith, of Smith & Kirkwood, and sell for about $38; but difficulty is anticipated due to the fact that the radio patents are con- trolled by a company in Buenos Aires and patent interference is anticipated. Radio World, 52 issues, $0.00. Subscribe direct or through your news dealer. $6.00 a year, $3.00 six months, $130 three months. Radio World, 1493 Broadway, N. Y. C Digitized by Google

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RADIO WORLD BECO" RADIO FREQUENCY SET m to **• testers 3 Radio Frequency S Audio Frequency and Detector All on 4 Tnbea Blflsell Engineering Company lgl-ltt W. Mtfc BTBBBT, NSW TOU INSU-LITE £ l/i" — Jl per m. ta» A »/l« — .tlJ per aq. In. N 1/4" — .M per aq. In. E DEALERS: Write for dUcom m. ^ General Merchandise Co. S 140 Market Street. Newark, N. J. $4 CRYSTAL SET THE LITTLE WONDER" KM UNMOUNTED Wonder in name and a wonder in per- formance. Cannot be equalled (or the price Catches distinctly everything broadcasted within 30 miles. Send for FREE catalog, describing oar "Little Wonder" set and listing radio sup- GUARANTEED, TESTED CRYSTALS 20c Radlocite. . Radl-OPlate Holloway m Third A* Co, Inc. New Yarn City G ITU ENS TRUTONE RADIO HORN -LOUD SPEAKER First one to eel oa taa day trial Money back Rwt.il Price tXIM la*J-*iee Loud Spswkar the best sa m. Iras ma. wnrr rsdl ■si try Tiaisst sad sswpere It wttb srsai, TOO SWI tad Tratess u» bxt rear bmbst be istasiiil It E awl as s ua-dar trial aim I eeataa. If est ssrrtad ar rsar easier wins as Dutrxbuion east Dtaitri. awwe/ AUTO PARTS MFG. CO. HIS Trembly Ave.. Detrsat, Mich. Future of Electricity la Next Swreea Years It Mast Accompli*, aa Mack aa It Has in Its History BETWEEN now and 1930, the electrical industry will be called upon to ac- complish as much as it has already ac- complished so far during its entire his- tory, and between the years 1930 and 1937 it wit! have to do four times as much, declares Guy E. Tripp, chairman of the Westinghouse Electric and Manufactur- ing Company in an article on the "Future of the Electrical Industry" in the current issue of the "Magazine of Wall Street" Until recently, the electrical industry, like most industries, says Mr. Tripp, de- veloped haphazardly and grew by blindly following lines of least resistance. In its early days, no one could estimate its possibilities — or rather, those who did foresee the immense development that has actually taken place, were derided as visionaries. To-day, the chief factors governing electrical progress are known with a reasonable degree of accuracy; and provided that no radical industrial or economic changes take place during the next fifty years, the electrical industry will, during this period, in all probability develop along well defined lines. One of the established facts is that the United States can use to advantage prac- tically all of the electrical energy that can be generated within its borders. Everyone concedes the superiority of electricity for lighting; for driving in- dustrial and mining machinery; for pro- ducing heat for industrial processes; for the manufacture of many chemical com- pounds, such as abrasives and fertilizers; for supplying power on the farm; for cooking, heating and operating a variety of labor-saving devices in the home; and for limitation need not worry the present generation, or the next. We have avail- able in the United States about fifty million horsepower of water power, of which only about eight millions are now in use. It will be many years before all of this power is developed; and, when it is, it will be utilized in conjunction with huge steam plants that will produce power from about one pound of coal per kilowatt hour. Though our fuel supplies are undoubtedly diminishing, it will be centuries before they are exhausted at this economical rate ; and by that time some of the newer forces, with which our physicians arc busy, may be at our disposal. The real limitation to electrical de- velopment is set by finance. The nation's present annual income is figured at about seventy billion dollars, of which the average surplus available for permanent investment, after providing for the needs and pleasures of our people, is about ten per cent. From this surplus must come the funds for all permanent improve- ments of every kind — every addition to our railways, mines, factories, farms, homes and highways. "TUNING IN" IE IS VERY SIMPLE WHEN YOUR SOLDERED WITH THE NEW "POST SOLDERING IRON" RIGHT TUNE IS WHtN YOUR CONNECTIONS ARE WITH THE NEW POST ELECTRIC COMPANY M EAST 42ND STREET. Dlv. in NEW YORK OUR NEW Dry Cell Socket, made aa a Beret clple, sells for eaty 60c. LINCOLN RADIO CORP. 11* W. *Slb Street N. Y. City wttoeati oeat ta asjo hi a* Til CORACO RADIO CONCERT THE CORACO COwtTANY, It* wast 4 tad •west mc ■ i 531 SO. DEARBORN ST. CHICAGO. PRICES SMASHED Seek ssls hat srtsted sew frltods sad sessss MSjm — * Send avd for srawd. Teen Ins fallen; COaPltTI SCCENCRATIVE VACUUM TUSI SIT Our Prlte • Pins! — Bsl.llls— T-ilJ- drlBsd. 1 1 .St AaVsV— — *Jbbw*9 IM- ■ . ■ .7 • SJUtesa -nub palau wife awL ■esb Is. I* At ■ear swltab ttoee with set. Bub Is. *4 .If ■ (bt MadLaf paste. Nut. I pitted Tee tiJuk users' •' tit.'.'.'.'.:.'.'" J* At 1 SJaaual rhssstsL mrhest srsds. ,M I.I* 1 ssrss esaetsr rsvrtewj taps t.IJ S.St 1 It plau rsrtabts saadssaar I.tl I. It 1 tabs ssstx — Moulded 41 .SI I srtdj randeaeer sad leak I* .11 I pbsas ssadsnssr it .tt I tabs «s« tupped 15 t| II fast sp.sh.tu tsetse • 4s .41 A* It test Uaasd eeppsr tins ill Is I BlT^*rltLi all t Uj illii. L"-' M aaaais ,i* .n HIM 130 0? Otasr srtialss au.se st rastiw frsa sar tot. arwe UM era— Dsterur tabes— Oaalntbsw — NOT «*ata tl.tl ll.lt Crystal dsterur st skwad type tt I SI Trmnatsraur— Asdls frsqeracr .... Ill 4.1* Deable tlldt uuaw— kassksd dews. Call eased 1 II .... T nret ssuplor— enacted dswa. Cats) wsaad j I) leser atuptof — we tod 7.11 tt.lt Vuloawe — Harewaod suun 1 %". I -tabled t.tl 4 M rw rsrw— isss tbsu i.ii i. ti Heliasss— 14*1 sasss 1.71 ii.m »suni BJIartns 1100 seas* *.t* II It Bksrprtau sl'lns detail ef 1 step T»oMi!ta"sw 1 1 Iter ' ' ' '. '" '*' Tn™sue',swpUfl.r BBwawtSfc"'' " " sshlo.t . || |t ti.** TT?2" is.6* *" "> "btaai t-i It- wind imj it.** •sal tw ii.t tewsr «• «■*«■ 4,rmt f~w ebses. Gw*>(f • g*>ld MVySsrt t» rttiarTi far rasWta m tt - ahasss. YOU MUST *t PtIAIEO. Radio Parts Manufacturing Co. 1* Perk Place W ret Detroit. Islcb.

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26 RADIO WORLD Instruction Books of tie RADIO READING COURSE $1.97 Learn how to deslsn. oonstrutt. Install, operate and nala- taln all klndi at radio apparels* Nt testes* «tady. A eonmlete radio education. Course odlud and approved Of Prof. J. H. Msreerett. Up-to-date, aaturata. templets. SEND NO MONEY. Just send your nam* and sddrets and pay postman only $1.97 and you own this flfo-book Badlo library. Writ* today. Dept. RW4. RADIO COURSES, Inc., 552 7th Ave., New York JS V. Loud 8osaker for Any Crystal 8«t by Using tee Stainmetx Amplifier Nt Sttraot Bstttry Required Amplifying unit uses Weet- inghouse Tube and requires a single dry battery In plan of a storage battery. Tube and ' Batteries for this unit 17.95. This makes the unit complete for operation. For a two Stage Amplifier use two of these unite. STEIN Mm PHONES are of 2000 Ohsn SS.00— S00O Oil art »6.50 Esiual to say $10.00 or $12.00 Send to. fsr Oatateetie. Steinmetz Wireless Mfg. Co, Inc., 8700 Pens Avesiie Wlussion. Pa. — rV. T. TUBES Guaranteed, Detector . . .$250 Amplifier 2.75 1-V8 Volt Tube 5.75 Socket for Same 75 Suneco Adapter 1.20 Genuine V.T.I 545 WATCH OUR LONG LIST OF SPECIAL8 — NEXT ISSUE. footsie must be added with ronluaaee. All car- tels latexes). Only best materials wt ewer. Radio DistributJna- * Ante Supply Co. 04 West oetb Street, New York City Broadway- 7th Ave. Subway Or* or 9th Ave. "L" The Latest and Most Essential Part of an Efficient Tube Set Variable Grid Leak and Micon Condenser (Combined) Obtainable In an unbroken rmng-e from aero to 6 megohms — all Intermediate points. Fixed capacity — .00028 M. F. Improves your set wonderfully by Clarifying Signals Lowering Filament Current Increasing Battery Life Eliminating Hissing Price Only $1.00 At your dealers— otherwise send us pur- chase price and you will be supplied without further charge. Manufactured by CHAS. FRESHMAN COMPANY, Inc. 97 Beekman St. New York City Home of Micon A Antenella "HOLIDAY RADIO GIFTS NUMBER" of Radio World will be issued December 9. Last copy will be accepted on this number up to November 30. Radio World, 1493 Broadway, New York. Broadcast Bill's Radiolays By William E. Douglass **p HANKSGIVIN" DAY at our house is •*■ a big event each year, when our folks get together, don't let nothin' interfere. There's me an' Min an' little Bill, an' Sister Jennie too, and my Aunt Soph from Goose Grease Creek an' also Uncle Lew. Then there's my brother Charley who works in a jewelry store down east in "Little Ol' New York." You know, he makes me sore the way he acts since he's been East with all his city tricks an' makin' fun of all of us — refers to all of us as "hicks." His wife, she ain't much bet- ter, puts on dog an' carries on, gets up about nine-thirty after all the work is done. Of course, there's Jim, our hired man, dressed in his Sunday best, with, bran' new yaller button shoes an' fancy cross cut vest. Maw an' Paw live here with us; Maw helped Min with the dinner an' when them two start workin' ^hey kin sure produce a winner. We had turkey, squash an' cranberries, spuds an' cabbage slaw, pickles an* homemade preserves, the best you ever saw. Maw mix^ed up some biscuits — Boy I they'd melt right in yer mouth, she says she learned to make 'em when she lived away down South. But when it comes dessert time, there's where my wife takes the prize. There aint no one kin beat her makin' mince and pun- kin pies. The dinner started off with grace then each one had to tell what he a2Ef snwwMonS ^▼/•'asTe' had to be thankful fer besides just bein' well. Dad said that he wuz thankful he could have his children here so they could be together fer at least one day , each year. Charley's wife said she was glad she had her "darling pet," — my Dad just give her one good look, she aint tergot it yet. Aunt Soph and Min an' Jennie, Little Bill an' all the rest gave thanks fer all the favors with which each one had been blessed. An' when it came to my turn to speak I guess most of them thought I'd say how thankful I wuz for the crops this year has brought, but that's right where I fooled them fer I'm thank- fulest I know because a feller called on me about a year ago an' handed me some happiness I never will ferget. You've guessed it right— for that wuz when I bought my wireless set. (Copyright 1922, Westinghouse Electric & Manufacturing Company.) "Radio Golf!" Next? SILENT periods between broadcast pro- grams have been instituted in Boston by Radio Inspector C. C. Kolster, so that fans may have a chance of tuning in long-distance stations without experienc- ing local interference. They can now play "radio golf," as it is called, when trying to receive distant stations without sitting up lat^ at night. Big Show Getting in Shape Space for American Radio Exposition Being Taken Up by Leading Firms THAT the American Radio Exposition, to be held in Grand Central Palace, New York City, December 21 to 30, in- clusive, promises to be a success, is em- phasized by the large companies exhib- iting that have pledged their co-opera- tion. The exposition has the support of the National Radio Chamber of Com- merce and, also, is sanctioned by the Radio Apparatus Section of the Asso- ciated Manufacturers of Electrical Supplies. It will be one of New York's big fea- tures. The slogan, "This is a Radio Christmas," has caught on. Many firms connected with the wholesale and retail ends of the business feel that the com- bined movement will result in a remark- able trade stimulus. The exposition to be held in the Pal- ace will be the first of a series of annual shows national in scope and analogous to 'such expositions as the annual Automo- bile Show, Motor Boat Show, Silk Show, and the Flower Show. All of theas expositions have been a big incentive to buyers in their respective industries. Dealers from many parts of the country visit them, as well as the consumer public The show at the Palace is primarily a manufacturers' official exhibit, but deal- ers and jobbers representing manufactur- ers will also display. Special morning hours will be arranged for dealers in the morning. During these periods the public will not be admitted. With the exposition enjoying the sup- port of such exhibitors as the Radio Cor- poration of America, De Forest Telephone & Telegraph Company, Western Electric Company, National Carbon Company and others, the attractiveness of the various exhibits is assured. Frank Hitchcock, former post-master general, is head of the American Exposi- tion Company. Walter Gordon Clark is vice-president, and Harold Bolster, secre- tary and treasurer. The offices are at 120 Broadway, New York City, where L. S. Byers, executive secretary, is in charge. Some of the prominent manufacturing corporations that have engaged space at the exposition include: Western Electric Company, Radio Cor- poration of America, C. Brandes, Inc, National Carbon Company, Novo Battery Company, Sleeper Radio Company, Gen- eral Insulate Company, Sound Wave Cor- poration, Pacent Electric Company, Stromberg-Carlson Manufacturing Com- pany, Holtzer-Cabot Company, National Airphone Corporation, Clapp - Easiham Company, Hutchison Radio Company, Henry Hyman & Co., De Forest Radio, Dubilier Condenser Co., Inc., Coto Coil Company, A. H. Grebe & Co.,- Weston Electrical Instrument Company, Ameri- can Radio Relay League, Executive Radio Council, Burgess Battery Co. To Germany on Telefunken Sale A LFRED FRANKENTHALER, a law- yer of 120 Broadway, took passage on the Cunarder "Aquitania" for a hurried trip to the Continent to represent many Germans whose property here was seized by the Alien Property Custodian. He said that the sale of the Telefunken wireless concern by the Custodian "for a nominal consideration," had led him to urge upon Washington an amicable adjustment for his clients and that satisfactory progress was being made. He believed the Win- slow resolution providing for the return by the United States to Germans of sums up to $10,000 would soon become law. Subscribe for RADIO WORLD. $6.00 a year, $3.00 six months, $1.50 three months.

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RADIO WORLD Radio in a Talking-Movie THE General Electric Company through its radio broadcasting station, WGY, Schenectady, New York, recently told thousands of people listen- ing to the program that a new device, other than the phonograph, was being used to "talk" into the radio transmitter. But no particulars were given of the device used. Then came Thomas A. Edison to the Schenectady plant. He had not been there in twenty-five years and there was much to show him. Being the in- ventor of the first device to record speech so that it could be reproduced, he was intensely interested in this new ma- chine. So he was taken to C. A. Hoxie's ex- perimental room in the General Labora- tory, where the pallo-photo-phone, in- vented by Mr. Hoxie, was shown and demonstrated. Here a film, which looked in every respect like a motion-picture film, was run through a machine with a powerful light thrown against it— just as in the motion-picture projection ma- chine— and from a loud-speaker and head phones the voice was heard, full and strong, with all its variations of tone, all its stops and hesitations, all its vital quality inherent in its reproduction. Edison marveled, "What next?" he asked. There are two great possibilities to this machine. First it makes possible the Law Storage Battery Constant voltage, Urge amperage. Win ram two oMatha without raofcargtag Attraction Dnltrt" Ductmntt Writ* ftr Drtmlt WILLIAM LAW COMPANY R. L RADIO GOODS AS GIFTS Be sure to be represented in "Holiday Radio Gifts Number," out December 9, Copy for this issue accepted up to Novem- ber 30, Radio Would, 149 Broadway, New York. FOR CHRISTMAS "The LittL Wonder" |H m CRYSTAL SET «p4 $2.50 UNMOUNTED Just the git for your boy or girl. Free catalog a> I GUARANTEED, Galena and 9 A _ TESTED CRYSTALS Radtodte....*UC* Radi-O-Plate Panels. All auwa cat to order. Hotloway Electric Supply Co, Inc. Z|g Third Avenue New York City talking movie, for on a film of the nor- mal width can be the picture and voice, absolutely synchronized. The picture and voice must work together, at all times for both are a part of the same film. Secondly, it means a boon to radio broadcasting studios. From a central ■studio, say in New York City where most of the great artists are located, the artist can sing, play some instruments or talk, into this machine which produces the film. Copies of the film L. T. Robinson, engineer in charge of the General Engineering Laboratory in which this machine was designed, ex- plains its operation: 'This is a device for the purpose of recording sounds upon a photographic film so that the sound may afterwards be reproduced in ordinary telephones or loud-speakers. The record is made by causing the sound waves to produce vibrations on an exceedingly minute and very delicate mirror. A beam of light reflected by this mirror strikes a photo- graphic film which is kept in continu- ous motion. The film, when developed, shows a band of white with delicate markings on the edges which correspond to the sound which has been reproduced. On account of the exceedingly small size of the mirror, its low inertia, it is pos- sible, by -this means, to produce a sound record which includes the very delicate 'overtones' which give quality to speech and musical sounds. This has not been so successfully accomplished by any other method of recording sound waves. "The reproduction of the sound from the film is accomplished by moving the film in front of an exceedingly delicate electrical device which produces an elec- tromotive force which varies with the amount of light which falls upon it. In the past, attempts have been made to produce these results by means of selen- ium cells; but a selenium cell, though it responds to the changes in the amount of light which it receives, does not respond with sufficient promptness to produce good results. There is a sluggishness in the response which seriously interferes with the quality of sound which is pro- duced. "By an ingenious combination of vacuum tubes, there has been produced an apparatus which responds to varia- tions in the light falling on it with a speed of light itself, or with the speed of propagation of wireless waves into space. Therefore, when this film is moved continuously in front of such a device, the device produces an electric current which corresponds very accur- ately to the original sound wave. This electric current may be used to actuate a telephone or loud-speaker. It has been used at the General Electric radio broad casting station. The voice of the an- nouncer was recorded on a phonographic film and sent out with such accuracy that it was impossible to distinguish it from the voice as directly transmitted from the station." RADIO FINDS A BETTjER CONDENSER Baylcy's 23-. 0005 and 43 Plate .0011 Variable Condenser la what Radio has found. Its plates spaced close give It the fin- est tuning qualities. The plates are assembled as a solid Integral part of the wholo by the die cast process. It Is Impossible for any plates to loosen In service. Each condenser has our money-back guarantee. Prion. 83 Plates $3.48 each 43 Plate* 13.715 each TO JOBBERS AND DEALERS A SPLENDID PROPOSITION Bayley Condenser Co. 105-109 Vanderveer St.. Brooklyn. N. Y. THIS IS the "SUNEC0" TUBE ADAPTER Eliminates the Storage Battery The "Suneco" Adapter allows the use of the Aeriotron WD- 11 dry cell vacuum tube in any standard socket. Minimum dielectric loss. Minimum induction effects. No soldering to corrode. If your dealer cannot supply you send money order or cash to Dept. W. Price $1.50 each Jobbers and dealers write for proposition W. Son Eqi 67 E„h.^ PLc New York

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RADIO WORLD Agents ^ LAMS KANUVACrUMB OV BHJKT8 waste. Agents M sell saaiilala Una ef Maria Aim _«e mm. Breuulre gmm «U releas. Ne euttel v merlssii required. Write IW In* ilaatl MADISON «HIBT ttOAM _ SOT Broadway No Ters. M. T. RADIO MAILING LISTS Mr M, If .M SKIMS ess «: Mr ML T.M nUDI CIBCI-1.AR ADDRBMtirO OO. log W ADA— WHT MIMM. «U. Those Broken „ Detectors [Save'550 lAiriDlifiers Vacuum Tubes Can Be Repaired U your dealer don net ljiew. MBd direct u oi> Harvard Radio Laboratories MS High Stmt BOSTON, MASS. Tuber returned P.P.. CLO.D. Do Your Buying At PERMANENT RADIO FAIR Hotel Imperial 32nd Street and Broadway New York City Buyers — S. It alBMt iBMMiMe • |sr set. Prttf tWflSty*wVB Mats frlrVV. "PT" CRYSTAL CONTACT CO. Box 1*41 BOSTON », Do Ton Like Clear Tone— Sharp and Distinct T If so try MARSH'S Vernier Variable Condenser AT LAST Made In Three Style*. Dial Kaefc sad Screws Complete. Felly Onaraateoi ■T-Flate • *LM It-Plate • S4.7B 11-Plate « SUi ■fall orders promptly Blind. F. P. Marsh, 145 NicoU St NEW HAVEN, CONN. Quality, Detign + WorkmatuMp + Material = RELIABILITY ^RADIOj^ Simple to Use . Just pint 110 in St I any lfO v. A. C I lamp socket— st- f tacb clips to bat- ' tery— turn on cur- rent and you hare your own chart- ing plant. A compact portable Recharging; unit that will fully charge a 100 AH battery overnight (or Sc. to 10c At your dealer t or write King Electric Mfg. Co, Inc. USl FUbnore Annua Buffalo, N. Y. THEY ARE GOOD ^"SBiffl SUp out the metal diet end slip In the MICA- P1IONB. Beiult — Clearer, bettor tene, all note*, eliminated. Write for drrular. Dleeosnta ts dealer, end Jobbere. MlCAPnOMBS aril sad. Radle Mlei Product. Ce.. 156 E. 4Sd St.. MM Vert YOUR NEWSDEALER will deliver RADIO WORLD to your home. In order to be euro of r<*tlna RADIO WORLD regularly, and of not miealng a single issue, we suggest that you either subscribe direct or through your news- dealer at M M a year (52 iuuee), O.S0 six months, and J 1-51 three months. Or instruct your newsdealer to deliver RADIO WORLD regularly to your home each week. Dealers will take standing orders and make deliveriee of paper whenever requested. Radio World. 1« Broadway, New York. Digitized by Google

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RADIO WORLD 29 R «m#X kr Dealer* tor Rillabmtj AIIO STORES CORP. ANCE UNI 11^ ETC HI WM 14t» I FRS ALL MOLDED UNIVERSAL COMBINATIONS • Balta la t W.M.B. IMM TufaMfl ^ F. B. B. IMM Tarlaeoapler* •» •• ». B. •. IMM auk Wlndlx*.... **» Ban* Windings an Interchangeable tar direct mounting en either TirknuMr ar Vartocoupler. Universal— Accurate — Interchangeable ■at tncludea two Federal Traaaformern, Condenser, two-molded varlometera, molded rarlocoupler, tbraa V. T. eooketa, ftlament rheoetata. dial* Read 'Wm Madias poets, swltoh polau; la attrae- Un cabinet and drlllad paaal: eomplete, ready to book A till Radio for.... F.R.S. Radio Corporation D Kaet Fan St. Detroit, Mick. ^$40 WE NEED RADIO WORLD, dated April 8 and August 1 K yon hare copies yon don't re- quire, mail to tbU office and current issues will be sent you (or tbem. RADIO WORLD. 1493 Broadway. New York. Tropical Radio Company Gets Miami Naval Station THE lease of the Naval Radio Station at Miami Beach, Florida, was awarded to the Tropical Radio Company of Boston, the highest bidder in the recent call for bids. This company, which is connected with the United Fruit Company, offered to take the sta- tion for eighteen months at an annual rental of $3,600, with permission to ex- tend the Rase an additional year. The Radio Corporation of America, and Cut- ting & Washington of New York, also filed bids. According to the terms of the lease, the Tropical Radio Company must re- place the old rotary-spark set with modern equipment which will reduce the objectional noise to a minimum. With the enactment of necessary legis- lation, it is understood that the Navy will ultimately offer the station for sale. Radio Aids Einstein Tests oPECIAL radio time-signals sent from O NSS, Annapolis, for the benefit of scientists in the Indian Ocean working on a test of the Einstein theory of rela- tivity during the recent solar eclipse, were nearly twice as audible as those of a commercial station, the United States Navy has been advised. At least their time signals reached Paris satis- factorily. A radio station there reports that a comparison of the time signals sent out by the Navy with those transmitted from Rocky Point, Long Island, showed that the audibility of the Navy signals was 158.3 compared with 87.5 for Rocky Point on the audibility scale. Reports from Australia and the Indian Ocean have not yet been received. Naval signals were sent out on 17,145 meters and those of the commercial station on 19,000. MICR0STAT Vevaiar Rbeoetat Tba Rbaoetat w«fc a UN nisiiat Va At $1.40 MICROSTAT COMPANY WIUJAMSFOBT, PA, TS To the Man wrth an Idea I offer s comprehensive, experi- enced, efficient serrice lor bis prompt, legal protection, and tbe development of his proposition. Send sketch or mod tioa. (or advice ss through prior United etc Preliminary i (urnished without charge. hty experience and (smiliari various arts to accuri go to any expense. Best to at raluabls In famed an. and (era far precarlr ffatlaalnt rour Idea, (res at raqean. Writs Mar. RICHARD B.OWEN,p«t.«t L»» I17S-P Wsahrarth Bids . New Vara Cttv niliarity with y enable me UNION-RADIO. PHONE TIP JACKS FRONT (Outside) VIKW (Patent Applied For) They are valuable wherever head phones are to be used. Especially convenient in connection with CW circuits. Countless uses have been found for them. The use of binding posts to connect phone tips has always been unsatis- factory. It is difficult to keep the tips from falling out of the binding posts. These Union Radio Jacks will accommodate any telephone cord-tips manufactured. To mount them on any panel, just drill a hole, using a 7/64 drill, insert the bushing, and screw on the lock nut which holds the combination tension spring and soldering lug in place. The tip when inserted is firmly held. And a good electrical connection is assured at all times. These Jacks eliminate the buying of an expen- sive telephone plug and Jack. Ideal for experimental circuits or in any part of a set where quick changes are needed. They accommodate wire up to the thickness of telephone tips. 25c. A PAIR We also manufacture complete receiving sets, 2 step amplifier*, variable condensers, receiving vacuum tube receptacles, condt-nsite dials etc. Our catalog M, "Radio Apparatus," sent on request. WHOLESALERS AND RETAILERS rVrlie for our liberal proposition. Sample* of our "Quality Prtoluctt" tent on requett. UNLON-RADIO-CORPORATION 200-MT PLEASANT~AVEN U E ~ N EWARK-NJ. NEW- YORK- OFFICE — 1 le>WEST»32=-STREEt. um BEAB (la aide I VIEW Digitized by Google

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OK EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT k A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS TUa Intended for mi ybody who warts quick action an short snnoishrainonts of ilADIO WORLD will Baa that it pay* to rood Hmm col' this isu sinusal wffll appear la RADIO WORLD on tha am-i t Is in the radio is, copy Tha rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEFT. the baying, palling, ovary week. Advertisers will _ ton days aftor copy roaches as. at this office tan days before publication, RADIO WORLD CO* MM ■roadway, N. Y. C. (Phone, Bryaat «m) USE YOUR PRINTS with new Holiday Greet- ing. Hsrper Syndicate, Columbus, Ohio. PATENTS — Electrical esses s specialty. Pre- war charges. B. P. Fishburnc, Registered Patent Lawyer. JK McGill Bldg., Washington, D. C AERONAUTICAL MOTORS, SO H. P., New $175.00. Weighs US Lbs. Complete. Rogers Air- craft, Route 1, Box t. Ft Worth, Texas. Exchange Jelly interesting letters through our Qnb I Stamp appreciated. Betty Lee, Inc., 4254 Broadway, New York City. MEN WANTED for detective work. Expert- ence unnecessary. Write for details explain- ing guaranteed position. J. GANOR, former Gov't Detective, St. Louis, Mo. WE NEED RADIO WORLD, dated April 23 and August 5. If you have copies yon don't re- Suire, mail to this office and current issues will e sent you for them. RADIO WORLD, 1493 Broadway, New York. FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO," Write today for complete list of premiums and our special sub- scription offer. "RADIO," Pacific Bldg., Sea Francisco, Cat ISSUES OF RADIO WORLD from April 1 to Oct. 7 (27 nam ben) for 15c a copy, or the whale lot for tS.ll Or send as 16.00 for one year sad start with the first number. RADIO WORLD, 1493 Broadway, New York. CASH FOR OLD GOLD. Platinum, Silver. Diamonds, Liberty Bonds, War, Thrift, Unased Postage Stamps, False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash sent, return mail. Goods returned in ten days if you're not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. ASTONISHING results Rokay Regenerative Hook-up without use of Variometers varioeona- lers. switches, tens, etc. ONE SINGLE CON- DENSER CONTROL ONLY. The. coming re- ceiver. Simpler then s non-regenerative — better than any regenerative we have tested. Hook-up, •LOO. Money Orders only. Savas yon $10.00 ia building your own. With properly wound cods, $3.50 post paid. Complete receiver parts on wood SAVE B TO NX ON ALL SUPPLIES. WE SELL SUPPLIES ONLY. LARGEST STOCK. $1.50 Round Telephone Plug, 79c; Fist, 60c 16.00 Arrow Variometer, $3 JO. Moulded Mack Variometer, $4.75. Six Dollar Manhattan Tele- phones, $4.40. Best Quality V. Condensers with Dial, $2JS. MONEY BACK Guarantee. Include AMALGAMATED RADIO SUPPLY COMPANY, MBA WILLIAM STREET, NEW YORK CITY PATENTS Protect your invention today. Write for 1932 Illustrated Book Free. Radio, Electrical, Chemi- ~ ' ax- 110- cal and Mechanical experts. Over 3D years' ex- perience. A M. Wilson. Inc. (Radio 3 ARH), 110- 18 Victor Building, Washington, D._C (Successors b. se with Vacuum Tube, $8-head set and "B" Battery, $21.35. Express paid. Rokay Electric Co., Ingomar, Ohio. to business established 1891 by A. M. Wilson.) Manufacturers of Rogers Radio Receivers and Rogers Receiving Radiometers. Rogers Radio Company, 5133 Woodworth Street, Pittsburgh, Pa. INTERESTED IN JOURNALISM? The Star Reporter is for Journalists. 50c annually. 5c sample. Box 55, Times Square Station, New York. NEWS AND GOSSIP OF THE STAAW-Seed 10c for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4 JO year, $2.00 six months, $1.00 three months. Mew York Star Co., 1493 Broadway, N. Y. EDISON B. BATTERY UNITS-One positive and one negative plate for 10c. 18 sets will make a -24-volt battery. Wilkinsburg Wireless Shop, 711 Penn Avenue, Willcinsburg, Pa. RADIO HOSPITAL. Radio sets repaired by practical radiotrician, and experimentations under customer's supervision. Mail orders fitted MELCO RADIO, -.:. 37-A Bedford Street, New York City. Are you familiar with all the radio symbols used in the various hook-ups published fat Radio World? If not, secure a copy of India World No. X, dated Sept. 23. In this issue wss a eeea- plete table of all important symbols used la radio censtraetioa and testing. Send IS cents for a copy, or $6.00 per year, and have snbeersytsea stsrt with that issue. RADIO WORLD, 149$ Broadway. New York City, N. Y. HOOKUPS— Over VJ0 blueprints to select from at 10c. each. Send dollar for trial order. Radio Supply Co., Box 292, Pueblo. Colo. FOR SALE— Regenerative Receiver, two stages, with Baldwin loud speaker. Complete, $135. Pichler, 414 E. 71st St., N. Y. C ATTENTION I You invent it. Let us make it. Models, dies, manufacturing. Sheldon Tool Co-, Rosedale Station, Kansas City. SENSITIVE Regenerative Receiver, very selec- tive, in mahogany cabinet, phones. Price $30. G. E. Igler. 255 Hull, Brooklyn, N. Y. • BROADCASTING MAP ' of the United States appeared in RADIO WORLD No. 8. Sent on receipt of 15c, coin or stamps: or start your subscription from that number ($6.00 for 52 issues). RADIO WORLD, 14H Broadway, New York BOOST RADIO. Wear a pin or button. It shows you are progressive. Designs and esti- mates furnished by official club jewelers. Tha Rankin Co., Radio Dept., 1118-20 Chestnut St., Philadelphia, Pa. EXCHANGE letters with new friends every- where. Pleasant pastime. Information for stamp. Smith, Box 3125-M, Portland. Ore. ' YOUR HOROSCOPE, business, changes, social, matrimonial prospects. Send birthdate and Tea Cents (sumps) for remarkable test reading. ZANYA, 202- J, West 105th St., N. Y. FOR SALE— Portable crystal receiver, $15.00. Regenerative receiver, $30.00. Regenerative and two-step, $60.00. Laboratory regenerative and two-step, $30.00. Also other apparatus. Send' for list. Herman Seikel, 48 15th Avenue, Columbus, Ohio. MODELS and patterns made. Light manufac- turing. Address H. W. Hathorn, Mason CSty, Iowa. 25% REDUCTION on C3 receivers. Write for circular. Cheney Radio Co., Cheney, Kan. RADIO SUPPLIES. We carry a big stock. Prompt shipments on all parts and comlete seta, including tubes, Magnavox, etc. An old concern, established in 1908, has $100,000 stock, small over- head. We allow more discount to dealers than anyone else. Send for our Radio Catalogue. Washington Auto Supply Co., Washington, DT. SALESMEN that have been or are calling oa electric or radio trade, see Mr. Rice, 6311 N. Clark St., Chicago. Static in the Tropics Only a Radio Operator Who Has Worked There Can Fully Appreciate It EVEN during the winter months static is very noticeable," says Charles A. Reberger, chief radio operator of the steamer "Atlantic," in "The Morning News," Dallas, Texas. "All day long it is a continuous roaring, grinding and crashing in the receivers. During the TOBACCO HABIT BANISHED QUICK, SURE, LASTING RESULTS Tobacco Redeemer banishes the habit com- pletely, almost before you know it. An absolutely scientific, thoroughly reliable treatment. No matter how long the habit, or in what form used, you will have no craving for tobacco after you take this pleasant, inexpensive treatment. This we positively guarantee. Your money returned without argument or question if not satisfied. Write for free explanatory booklet and proof of what Tobacco Redeemer has done for men addicted to the tobacco habit. Send post card or letter today. ■•well PhinMMl Co* Dept. 971 ct. Louis, Mo. hours of the night it is worse — far worse. Nine times out of ten the crashes will entirely blot out all signals. "It is very difficult to work through heavy static. Let me give you an idea. One evening we attempted to establish communication with a station in the Canal Zone, which was about two hun- dred miles away from us, and failed. It was absolutely impossible to even hear his signals, due to the heavy atmospheric conditions. A vessel only ninety miles north of us could not read our signals, although we were then getting twelve amperes radiation and had a fine, clear musical spark. Radio engineers claim a musical spark is easily read through static interference. "A few nights later, I had the pleasure of listening to Swan Island working a United States fruit liner. After this sta- tion had sent each letter twenty times, the vessel informed him that it could not distinguish his characters. Only an hour before he had forwarded his 'TR' to Swan Island and was no more than two hundred miles south of this land station. "If one should 'listen in' during one of those ugly tropical thunderstorms I guarantee you would think you were at the battle of Liige or in a boiler factory." Attention, Newsdealers You should keep a good supply of back numbers of RADIO WORLD on hand all the time. It has been the experience of many dealers that a purchaser of RADIO WORLD for the first time will almost immediately want the back numbers, some of which are already out of print and some of which are difficult to get. THE PUBLISHER WILL FURNISH BACK NUMBERS TO DEALERS DIRECT OR THROUGH THE AMERICAN NEWS CO. AND ITS BRANCHES. Dealers should hold their unsold copies for a reasonable length of time. RADIO WORLD of October 28 contained a full page of contents oi back numbers to that date. 15 cents per copy; any seven numbers for $1.00. RADIO WORLD, 1493 Broadway, New York. That Armstrong Circuit So much interest has been displayed in tha special article, "TESTED INVENTION OF MAJOR ARMSTRONG AMPLIFIES SET 10MW TIMES," by John Kent, that appeared in RADIO WORLD No. 13, dated June 24, 1922, the publisher decided to put aside a number of copies tor those who were not able to get this issue when pub- lished. Copies will be sent, postpaid, on receipt of 15c, or send in your subscription, $6.00, for oaa year (52 issues), $3.00 six months, or tl.SO three months, and subscription will be started with the issue containing the article about Major Arm- strong's Amphner.-RADIO WORLD, 1493 Broad- way. |^ Digitized by KIT ooglc

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RADIO WORLD Orange Label Tea Special lOt Tins Choice tea insures restful relaxation! See that your family is served more of this superior tea; a golden beverage that has a fragrance and flavor — supreme. Also sold in I lb., V2 lb. and V4lb. TINS Sample will be sent on request. Address: Ridgways, Inc., Department K, 60 Warren St., New York. COLD MEDAL San Francisco 1915 GRAND PRIZE San Diego 1916 Digitized by Google

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RADIO WORLD HUTCHISON The Final Word in Radio Apparatus f 1AM > ► - » i """°r"" pF I * * * TYPE SK This Complete Receiver is simpler to operate, more efficient, more selective, less fussy than any we have ever seen. Embodies the Arm- strong regenerative circuit, and many modern improvements found only in the highest grade instruments. Designed for the expert, but so simple that it can be handled easily by the novice. Every detail of workmanship and fin- ish is of the very highest grade. There is nothing finer at any price. Well known radio engineers have tested it thoroughly, and marvel at its simplicity and efficiency. The Type SK is a complete regenera- tive tuner, with detector and two stage audio frequency amplifier. Its output goes direct to phones or will operate any good loud speaker. Being designed for the usual broadcasting wave lengths (150 to, 450 meters) it is very highly selective in this complete range, and delivers a clear, pure signal, remarkably free from the usual distortion or tube noises. Offered only by leading retailers. If your dealer is not supplied, write us direct, mentioning his name. Hutchison Radio Company Canadian Pacific Building 342 Madison Avenue, New York To the Trade: The discriminating purchaser instantly recognizes the Type SK as an exceptionally fine instrument. Dealers handling it usually select it for their own store demonstrator. Jobbers and Retailers find it a ready seller, and their customers report unusual satisfaction. Our terms give the purchaser exceptional value and also provide a fair profit for the trade. Write or wire for particulars. Digitized by Google

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tonai Kaaio~WeeK 23 to 30 (inclusive) December 2 15c. atopy. War ear (Trade Mark) U S T Miniature Radio Transmitter Fits Kodak Case A N unusually interesting miniature trans- *^ mitter is shown in the accompanying photograph. It was built and design**! by Sterling G. Sears, and will give satisfactory service to the novice who is satis&ed with comparatively short range. The set shown has a transmitting range of about three-quar- ters of a mile and a receiving range of about seventy-five miles. The apparatus is mounted so that it fits into the interior of a kodak- camera case. Note the neat appearance and arrangement of the coils, batteries, and the miniature vacuum-tube. For B batteries, in this particular case, flashlight batteries are used exclusively. The reason for this is that they take up little space and afford the neces- sary plate voltages for the vacuum tub*. The filament may be lit by the ordinary bat- tery. As a means of inductance a spider-web coil is used as a means of controlling the wave length. The taps are shown on the front of the panel. The rheostat, with the miniature vacuum tube, is also shown. At the rear of this is the spider-web inductance coil with its taps, while the grid leak and condenser are mounted on the center coil. The batteries are at the extreme back of panel. The wiring is extremely simple. With a limited knowledge of radio, the operator • hcyild find this set efficient. It is a practical transmitter and may also be used as a receiver. (C. Ksdel A Hrrbrrt) e Records by the DX Night Owls! Send Yours In! CHRISTMAS NUMBER OUT NEXT WEEK!

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RADIO WORLD Pruden Reliable Radio Specialties For Good Results ! AJax Socket Rheostat A device for which amateurs and profea- alonala have Ion*, been waitlne. Elim- inates wlrinn between socket am *9 00 rheostat. List **.UU THE name "Pruden" back of stand- ard Radio Equipment is a guar- antee of mechanical excellence, perfection of workmanship and scientific correctness of design. Now, more than ever, when the market is flooded with inferior goods, it pays to buy standard trade marked products. You can pin your faith to "Pruden." Money- back unconditionally if you do not get com- plete satisfaction. Just a few leaders of Pruden Reliable Products shown here that will give you better radio results at no greater cost. Dealers write today for our interesting proposition. Phono-PtiBne Permanent Radio Detector The only fixed radio detector requlrlne a* adjustment. Used In place of crystal or vacuum tube detector. Glrea excel tent quality of sound without distortion, battery or tube noises. Detects teloitraph slsnals at several thousand miles. Detects broad- casttd musle mora clearly than vacuum tube dotector, and requires no amplifica- tion whero the Incoming sWnal has suffi- cient strength to actuate the sensitive phones. Ideal Tor use In regenerative circuits. Handsome, aubstantlal. suitable for as- sembly In the finest radio equipment. Guaranteed against Imperfection $3_50 or faulty operation. List each.. v Keystone Moulded Variometer Made of a apeclal composition — extremely light In weight and durable. Wave lenitth rangea from 150 to 580 Meters. Terminals conveniently arranged to afford fa con- nections and avoid crossing terminal wires. Rolor and Stator windings guaranteed not to loosen. $5.00 Brush type contacts. List each. v FREDERICK 993 Bergen Ave. PRUDEN INC. 5 Jersey City, N. J. Saturn Automatic Pluf The only perfect automatic plug, no need to take apart to make connections. First Insert the terminals Into the "Saturn and a perfect connection la made. So con- etructed that pulling of the cords makes the connection mora positive. 81 50 List each The best SOCKET for the DRY CELL TUBE 60c. LINCOLN RADIO CORPORATION lie W. 85th M. Manufacturers New York City SAVE MONEY ON HIGH GRADE Variable Condensers Direct from Manufacturers Take the middleman's profit and sell- ing; costs for youraelf. We sell you di- rect. These extremely accurate Instru- ments made by experienced condenser people are minus the decorative frills that add to cost. Price reduced to rock bottom without sacrificing quality in the least. Satisfaction or your money back. today for very interesting; clr- PRICES: 21 Plate $2.55 43 Plate $2.95 Complete with Mountiaf Screws Tour Order Filled by Return Mall No checka or money orders needed. Pay postman. Send the order TODAY, enclosing 5 two-cent utamns to cover mailing cost and receive your con- denser In a day or two. MANUFACTURERS' RADIO ASSOCIATION 90 East Kinney St. Newark, N. J. How Dr. Lee de Forest's Photofilm Works THE process is outlined in general terms as follows in a letter by Mr. de Forest to his representative in New York : "Taking the picture: "1. Sound waves (voice of the actor) translated into electrical waves. "2. Electrical waves translated into light waves. "3. Light waves recorded on the edge of the film. "Reproducing the picture: "1. Light waves translated back into electrical waves. "2. Electrical waves translated back into sound waves. "3. Sound waves amplified with loud- speakers placed near the screen for the audience." The stumbling block which has impeded other efforts to perfect the talking film has been the difficulty in exactly syn- chronizing the voice and the picture. This is important, since sound travels at 1,090 feet a second and light at 186,000 miles a second. Unless the word and action cor- respond exactly in time, as rendered by the talking-picture machine, the effect is spoiled. With the picture and the sound- wave on the same film, the time unity is preserved to the thousandth part of a second. Thordarson Transformers Dictograph Phones, - 3000 Ohms, $8.00 Value $30.00 Tab* Set, Special, $15.00 Amateurs:— We Pay Posts**. Perfection Radio Corp. of America Iff West 23d Street New York Cttjr GREAT ADVERTISING MEDIUM Radio World's special issue, "Holiday Radio Gift* Number," issued on December 9. Copy received up to November 29. Radio World. 1493 Broadway, New York. Canadian Radio Directory CANADA published its first issue of the "Official List of Radio Stations in Canada." This list, which was compiled through the efforts of Commander C. P. Edwards, director of the radiotelegraph service under the Department of Marine and Fisheries, contains a complete roil of every amateur, commercial, -military, and broadcasting station in the Dominion, and is corrected to August 1, 1922. A Completely connected Simply m connect la circuit. No taps te vSoltUr, no extra switch at aide, no electrical connec- tion to any shaft. Compact and rotor al- ways in cantor of field. M turns No. 22 green silk wire on primary. . Pestsala Complete wlta iadi eater ana $6.50 8ans esupler with retor tawarH ass end €*0 u without special connections Knockdown coupler with printed wiaslaf CI CA directions, complete, leu wire The W. J. Radio & Mfg. Co. 3020 Fourth Ave., So. MINNEAPOLIS MINN. WE NEED RADIO WORLD, dated April 22 and August 5. If you have copies you don't re- quire, mail to this office and current issues will be sent you for them. RADIO WORLD, VSJ Broadway, New York. Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered ma eecoad-claai matter, March 2s, 1922, at the Poet Office at New York, N. Y., wider the act of March J, 1879.1 A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. VoL II, No. 10. Whole No. 36 December 2, 1922 15c per copy, $6.00 a year K. of C. Leads in Radio Instruction for Veterans of World War (Both pnotot C Kadel & Herbert) • THE Knights of Columbus are conducting radio schools for the purpose of instructing vet- erans of the World War. Already nearly 20,000 veterans are receiving instruction in these schools. The large photograph on this page shows Instructor Thomas A. Berinati, at the left. He is instructing Ernest Vehstedt, a hero of the Argonne, in the workings of a half-kilowatt spark-gap transmitter. The spark- gap is the heart of the transmitter, and in this case, this particular gap makes it possible to secure what is termed a "pure, sharp wave." It is of the utmost importance that the student be familiar with the "how and why" of this gap, as it is vital when a man is taking examinations In* true ting a World War veteran in one of the radio school* of the K. of C, station ZAZK. How to solder a Marconi 1M-B receiver. for a governmental radio license. To the left of Mr. Berinati is the receiving instrument with its neces- sary array of vacuum tubes for high amplification. All of these instru- ments are of vital importance to the student who expects to be an expert operator. The small photograph shows the rear of a receiver of the Marconi 106-B type of tuner. This tuner has for its inductance and coupling the loose coupler as shown in the pic- ture. A wire is being soldered by Mr. Berinati. Once the student receives a li- cense, he has an opportunity to trav- el, and, if he is alert and m'akes the most of his eyes, camera, and note-

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4 RADIO WORLD Getting Results Out of Your Receiver By Charles H. Plath Schematic diagram of a slide tuning coU. By sliding the two sliders on the coil inductance the wave-length la changed. Drawn by Charles H. Math. WHY is it necessary to have an outdoor aerial in order that a radiophone concert may be received? This is a ques- tion that is being asked frequently, particularly in view of the develop- ment of Armstrong superregenera- tion, radio-frequency amplification and other systems, which will func- tion provided the loop aerial is ap- plied to them. This loop aerial does away with the outdoor aerial and makes it possible for most anyone to hear the broadcast.. The answer to the question is im- portant, because the success of the receiver absolutely depends on the aerial. In order to illustrate the opera- tion of an aerial, it is, perhaps, best to take the hydraulic analogy that has been developed by radio engi- neers as a means of describing an aerial. In reality, it must be under- stood that the ground and aerial act as a condenser — the aerial being one plate, the other being the ground. The tuner which, after all, is a vari- able inductance, is merely an ar- rangement that will permit one to increase the length of the aerial it- self. If one looks upon the aerial cir- cuit as a large trough of water he will understand its functioning a little more clearly. Only recently articles have appeared regarding the aerial problem ; but I am assured that there are still many who would like a simple picture of just how it takes its action. If we picture a water trough and place a paddle wheel in it, we can then see the action or wave motion. If we commence a steady disturb- ance in this trough by aid of the water-wheel, the water will be set into wave motion and will oscillate between the two ends of the trough according to the length of the trough; in other words, the natural frequency of the trough. If this paddle is moved back and forth at a correct rate of speed equal to the natural period of the trough it will set up waves of maximum height which, in time, will pour over the sides of the tub. If, however, the rate of movement is too fast or too slow, th« maximum wave- motion will not be attained. If we 6tudy the wave motion in the trough we will find that the maximum height of the wave is reached at either end of the trough, and that, as the water flows back and forth in an oscillatory manner, the great- est height is reached at each end of the trough. In our aerial circuit this action is reproduced when the incoming wave sets up an oscillatory current in the aerial circuit. It will be found that the highest voltage is at either end of the aerial wire, and it is necessary therefore, that these two ends be thoroughly and completely insulated in order to prevent losses. Now, we have exactly the same condition in the aerial circuit as we have described in the trough. If the incoming wave-length is too small it will not set up an oscillatory current in the aerial circuit. If it is too large, the same results will be obtained. With the incoming wave close to the natural frequency of the aerial, we can make up for any small dif- ference by means of an inductance that is connected in series to it. It is for this reason, therefore, that it is necessary to have a well-con- structed aerial, free and clear of all objects where the ordinary normal circuit is used in order to get best results. Radio Crop Service A WORLD radio-crop service has been established by the United States Department of Agriculture. The Department has representatives in many important European cities, who send re- ports of crop conditions to Washington. The information is then broadcast over the United States. A recent message from the Berlin reresentative was re- ceived in Washington and relayed throughout the country in less than five minutes from the time the news left Germany. Schematic diagram of a variometer which gives continuous variation of inductance. The second- ary variable condenser is necessary for good results. Drawn by Charles H. Plain. The inductance in the circuit will enable the amateur to increase the range of his set so far as the wave length is concerned, which is equi- valent to varying the trough in the analogy. The addition of a con- denser in series with the aerial will have a tendency to reduce the wave- length range of the receiver within certain limits. i The condenser in series with the aerial can be used for more flexible tuning purposes in the aerial. There is a very important point, however, that should be taken into considera- tion in conjunction with a series con- denser in the antenna. In the first place, it is a fundamental fact in electricity that condensers placed in series with each other reduce the total capacity of the circuit and that is exactly just what happens when you place the tuning condenser in series with the aerial, because the latter is also a condenser. In this connection, there is a very peculiar situation; if the detector circuit is connected to the aerial cir- cuit in such a way that this con- denser is included, a great stress will be placed on the detector. Conse- quently the efficiency of the receiver will be materially reduced. It is necessary to connect the de- tector circuit around the aerial tuning-inductance only. Whether this aerial tuning-inductance con- sists of a straight tuning coil, a honeycomb coil, or any other form of coil does not make any difference. The detector circuit should be con- nected around it in such a way that the series condenser in the aerial is not included. Digitized by Google

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RADIO WORLD 3 Sharp Tuning Will Help to Eliminate Interference MANY sets made are almost impossible to tune sharply; but whatever sort of an out- fit you have, an understanding of its tuning qualities will bring better re- sults both in reduction of interfer- ence and signal strength. Interfer- ence is one of the greatest studies in the science of radio. With a crystal set using a single-slide tuner as the sole method of tuning, there is no choice in adjusting. Simply move the slider until the greatest sound is obtained. Interference from other stations may have to be tolerated. With this set, it may be impossible to prevent it due to the fact that a direct-coupler receiver is used. A two-slide tuning coil offers a greater latitude of adjustment and, therefore, greater selectivity. It acts somewhat in the manner of a two-circuit, or loose-coupler receiv- er, with close coupling. The aerial slider should first be adjusted until signals are heard. The movement should be in the activity of the ac- tive end of the coil, or the end con- nected to the ground. When signals are heard, move the other slider until they are brought in loudest. The loose-coupler set, which is the inductive type receiver^ is the most efficient type for use with a crystal detector. In tuning such a set use close coupling — that is, have the secondary coil inside the primary coil. Set the secondary coil at some rather low value of inductance and adjust the primary by means of slider, or switch. The circuits are brought into resonance after the sig- nals are heard by adjusting the sec- ondary switch. Louder signals may be obtained sometimes by readjust- ing the primary. Interfering sig- nals may be reduced by lessening the degree of coupling. For short-wave sets using vacuum tubes as detec- By Arthur O. Curtis The schematic diagram (above) shows a tuning coil with a variable condenser across ths secon- dary. This mains the timing sharp and helps to keep down interference from other stations. This tuning oofl Is of ths single-circuit type. The schematic diagram (below) shows the Induc- tive type of coop ler. It has a primary and sec- ondary. Again the variable condenser which is of •MM mid. capacity, helps to eliminate inter- ference. This Is known as a vario- coupler and Is far more advantageous fat radio work than the iU. Drawn by Arthur O. Curtis. tors, the regenerative hook-up has proved the best. The tuning ele- ments in such a circuit consist of a vario-coupler, a grid variometer, a plate variometer and, sometimes, a series variable-condenser ^in the aerial circuit. Tight coupling should be used in this vario-coupler. Adjust the pri- mary switch; next, rotate the knob on the grid variometer until a howl or squeal is heard. Another squeal will be heard just past this point. Between these two points will be found a point of resonance at which the incoming signals will be heard. The plate variometer should next be adjusted until signals are loudest. It will be found that coupling varia- tion will make a slight difference in the tuning, or in the strength, of signals. It will be seen that the loose coupler has its limitations but it is far better than the tuning coil. It is more selective. It has .two coils. It is of the inductive-type receiver — that is, one may select the station he wants among others that are transmitting at the same time. It is easier to receive with a loose coupler as it acts as a filter which passes the signals that are tuned in and rejects the undesired signals. This is true to a certain point, for it is not always that a very pure wave comes from a transmitting station. If the transmitting station is very near the receiving station, it ftlso will be hard to tune out. Thus it will be seen that the loose coupler is much more advantageous than the tuning coil. The loose coupler probably is the most common tuning device used with a crystal detector. The lower diagram is a simple crystal detector, utilizing a loose coupler, also a fixed condenser across the head phones. Nine More Broadcasters Cimbel Brothers, Philadelphia, Licensed to Carry oa 4M Meter* THE following. Limited Commercial or Broadcasting Stations issued by the Department of Commerce, for the week ending November 17, carry on 360 meters: KFAV— Abbot-Kinney Co., Venice, Calif. WPAM— Awerbach & Guettel, Topeka, Kans. WHAL — "Capitol News," Lansing, Mich. WLAT— Radio and Specialty Co., Bur- lington, Iowa. KFFA— Dr. R. C. Shelton, San Diego, Calif. WNAY — Shipowners Radio Service, Baltimore, Md. WPAD— Wieboldt & Co., Chicago, 111. Two new Limited Commercial Class- B Stations on 400 meters are: WIP— Gimbel Brothers, Philadelphia. KHJ— Times Mirror Co., Los Angeles. Belgium's Rulers Become Radio Fans HP HE king and queen of the Belgians ~ have become radio fans. Accord- ing to recent dispatches they listened in to a test concert of the Maline Cathedral chimes, broadcast from the tower by radio. The suggestion of broadcasting by radio the carillon of Maline Cathedral, the seat of His Eminence, Cardinal Mercier, re- sulted directly from the successful broad- casting of chime music, on April 27 last, by WGY, radio broadcasting station of the General Electric Company. On that date, the McKim Memorial bells, now in the lofty tower of Epiphany Church, Washington, D. C, were played in the Old Meneely Bell Foundry at Water- vliet, New York. The foundry was con- nected to the transmitting equipment, six- teen miles away, by a telephone line. Colonel William Gorham Rice, of Al- bany, an international authority on caril- lon, heard of the success of the WGY concert Since the World War, Colonel Rice has been devoting himself to the rebuilding of war-torn Belgium. Digitized by Google

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6 RADIO WORLD Inventors! Here Are Some Things Sorely Needed in Radio By C. White, Consulting Engineer THERE are, perhaps, thousands of radio amateurs and novices with practical ideas concern- ing radio improvements that, prob- ably would net them modest for- tunes if they had the courage to get behind their ideas and give them the necessary scientific backing. That a man is not a technical expert in no way renders him disqualified to perfect a new radio idea; in fact, many inventions come from men who had very little technical train- ing prior to their conception of the lucky idea. If an amateur does not possess the right amount of scientific skill to perfect an invention, he should either take steps to acquire that skill or hire someone with the skill to supply the information and help him over the rough spots. I have personally known of many practical inventions along scientific lines that have proved profitable for the men who had sufficient foresight to seek the right kind of aid. Radio as a field for inventions is exceedingly fertile, and the wise amateur is the one who fully real- izes this and carefully sets his mind to work to accomplish some greatly desired improvement. Consider the radio receiver. We know that the art of transmission is far in advance of the art of reception, mainly be- cause we have spent more time for the development and research of more powerful methods of sending; yet the receiver has been given very little attention until recently. The fact that radio reception has long been neglected is quite obvious when one stops to consider that some deep-sea vessels are still using the old magnetic type of detector, which is much inferior to the ordinary crystal that many novices have in their small sets. Another proof that reception has been neglected is the fact the radio-frequency had to wait so long in the experimental stage before completion : and, in some re- spects, it is still in that stage. If we resort to the tuned plate-circuit for radio-frequency amplification the tuning of the circuit becomes too critical for an ordinary case of ad- justment and manipulation, while it is next to impossible to keep tuned if more than one stage is used. Then, again, if we employ many of the transformers for radio-frequency amplification, we cover the desired increase in range, but the band of wave-lengths amplified greatly cuts down the desired selectivity which is quite paramount for long-distance work. There is, no doubt, some compromise between the two which will give perfectly satisfactory re- sults and still give us selective am- plification; so it is up to radio fans to find that combination and have it duly developed. It can be done, and if some one will only take the time to think up a possible scheme and then try it out with the aid of some reliable manufacturer, or technician, reward for his efforts will follow. We need better types of tuning coils — coils that are relatively free from distributed capacity and have a very low effective resistance at radio-frequencies. In a recent test of some coils used in radio work, I actually found them not only to be extremely high in resistance loss but also extremely high in effective or distributed capacity. Now, since distributed capacity is a variable with frequency, it was actually found at high frequencies that the condensive action of the coil was greater than the inductive. This meant that the coil was nothing more than a condenser from the electrical standpoint. While it is true that the spider-web, and the honeycomb types of inductance are marked developments in the right direction, I think that there remains an ample field for further progress along that line. Specially stranded wire has aided to a certain extent, The Grid Condenser and Leak THE sensitiveness of a receiver is greatly increased by insert- ing a grid condenser and leak in the grid circuit in series with the grid of the tube. This usually consists of a small fixed condenser of about .00025 mfd., in shunt, or parallel, with the grid leak of about .5 megohms (500,000 ohms), though these values are not fixed value but should be adapted to the correct tube used. Simply defined, the grid leak is an instrument that will allow extremely small currents to "trickle" through. Grid leaks are generally supplied in complete units and are frequently encased in glass tubes for protection. to cut down high-frequency skin- effect, but, as we all know, there is still more room for improvement. We are just beginning to realize what may be done. In fact, the fore- most technicians and radio-research engineers are so swamped with pros- pects of development along so many lines that they are forced to set aside many promising ideas that need careful consideration. In the field of the short-wave, Mr. Marconi has asserted that we have entirely neglected the vast possibili- ties to be obtained from carefully planned study along this line. It hardly seems possible that we should plug away so many years on the de- velopment of the long wave for transmission of radio signals and completely — and for no good reason — ignore the realm of the short wave. Perhaps millions of dollars have been spent in the development of high-frequency alternators and different types of Poulsen arcs for generating long-wave undamped signals; yet the development of short waves has been generally over- looked. Amateur C-W stations have proved that with relatively small amounts of power they can send signals further than some commer- cial stations using many times as much power, I personally know of one amateur station, situated in New England, that has been heard at. rather frequent intervals in Hono- lulu and England. This station uses only four 50-watt tubes. The ama- teur transatlantic tests that are to be held this month will show us how short-wave signals will carry with a relatively small amount of power. I have given only a few sugges- tions of the needs in radio, but there are many more that are just as much needed as those I have outlined. For instance, . there is still wanting, a simple yet effective means of filter- ing out static interference. Inven- tions for increasing the selectivity of a receiver are favorable from the scientific point of view. Methods of obtaining distortionless detection and amplification of radiophone sig- nals are badly needed. Thousands of design improvements in every phase of radio-apparatus construc- tion are awaiting solution. If you have an idea don't let it go to waste simplv because you have not the means avail- able for skilful perfection and develop- ment. Digitized by Google

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RADIO WORLD 7 Radio Facts IRON, steel, or galvanized wire is never used for aerials, because they have too low a resistance. Cop- per is generally used, simply because it is a better conductor of electricity than any of the other conductors mentioned. * * * If your ground is poor, signals from broadcasting stations cannot be expected to be heard at any great signal strength. Signals may be so weak at times that it will be impos- sible to hear anything at all. This is very discouraging. When making a ground connection, don't wrap the wire around the pipe or radiator. w * * Body or hand capacity effects may be eliminated if the back of the panel is shielded with thin copper and grounded to the ground binding- post. Copper sheeting njay be placed a.lso between the various variometers, care being taken that the sheeting does not come in con- tact with any of the wires. The variometers should be spaced about 4 inches apart. * * * Electrically, the cage antenna han- dles a given amount of energy with less rise in voltage than any other aerial, and, therefore, has less ten- dency to leak to the ground. This advantage comes especially into play , when this type antenna is used for C-W work in transmission. * * * When high-frequency currents flow in a circuit, they travel on the surface of the conductor and are known as "skin effect." For this reason Litz wire and stranded wire are generally used in radio work where high-frequency currents are to be carried. Cost of Installing a Set A SIMPLE receiving-set which will copy commercial stations from a distance of 500 miles or more, is quite small. If all necessary in- struments are purchased, the cost should be under $50. When made by the experimenter himself, the cost of material is less. Experimenters who are really interested in "What it does and how it does it," find most satisfaction in mastering the details and operation of each instrument as they add to their stations. That is the way of the logical mind and, under cover of providing for real in- door sport, radio work offers to the younger minds valuable develop- ment in logical and analytical think- ing— more effective than school- book methods since it is accom- plished by real entertainment. Radio- Wire Tables By Frederick J. Rumford, EM.., R.B. No. 3 — Double Cotton-Covered Wire Showing the Number of Feet in a Pound and Fractions of a Pound APPENDED is the third of a series of five tables which the radio amateur will find useful for many purposes. The succeeding tables — "Single Silk-CoverecL Wire" and "Double Silk-Covered Wire" — will be published in early numbers ot Radio World 1 lb. 2M 370 461 584 74S 903 111S 1422 1750 2207 2534 2708 3137 4007 6108 6737 7877 9300 10000 11907 14222 The following tables have already been published: No. 1 — Enameled Magnet Wire, Radio World, No. 34, dated November 18. No. 2 — Single Cotton-Covered Wire, Radio World, No. 35, dated November 25. Motor Car Receives Radio Messages Size K lb. H lb. % lb. y4 ib. 20 37 74 148 222 21 46 92 184 276 22 57 114 228 342 23 73 146 292 438 24 93 186 372 558 25 112 224 448 072 26 139 278 556 834 27 177 354 708 1062 28 219 438 876 1314 29 275 559 1100 1650 30 316 632 1264 1800 31 346 692 1384 2070 32 382 764 1528 2202 33 587 1174 2348 3522 34 771 1542 3084 4026 35 842 1684 3368 5052 36 984 1968 3936 5904 37 1103 2326 4642 0068 38 1333 2666 5332 7998 39 1488 2976 5952 8928 40 1777 3554 7108 10062 J m • .J (C Central News) The above photograph shows a loop aerial erected en the roof ot a motor-car. It Important experiment conducted by the Marconi Wirelesa TaUfraph Company of The set was installed In the center of the car in order that the lead-in wire* from the loop might be brought to the set. Results were obtained thirty miles from a broadcastinc station. Note this peculiar loop aerial. It can be rotated from the interior of the car, making- It possible to manipulate the direction of the loop while receiving' electromagnetic waves from a broad- casting station. Loop aerials are being used by many radio amateurs. When the loop Is employed, radio-frequency amplification or the well-known Armstrong superregenerattve re- be used in order to get results. This loop has the distinction of Interference, a marked advantage over the outside aerial. Digitized by Google

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RADIO WORLD Arlington to Be Government's Radio Broadcasting Center WASHINGTON, D. C— With 573 private broadcasting sta- tions offering daily pro- grams, the radio public is apt to lose sight of the fact that the United States is also broadcasting informa- tion on many subjects. Six depart- ments are scheduled for daily or semi-weekly programs and forty- two Naval radio stations are carry- ing news of one sort or another. Requests for permission to broad- cast have become so numerous that the co-ordination of all government broadcasting has become necessary. A committee of twelve officials, rep- resenting as many branches of the government at Washington, is en- deavoring to supervise matter sub- mitted for public broadcasting over radiotelephone circuits furnished through the courtesy of the Navy Department. In order that the lis- teners-in may receive the maximum service with a minimum of inter- ference and without duplication, this committee was appointed last spring at the suggestion of Herbert R. Hoover, Secretary of Commerce. It is known as the Interdepartmental Advisory Committee on Radio Broadcasting. Although the com- mittee meets biweekly, its subcom- mittees are busy almost continually with this work. Scope of Interdepartmental Work Demands for broadcasting of tele- graph matter, as well as telephone, are constantly increasing and the scope of the committee's work is gradually growing greater. Recent- ly the question of broader activities and supervision has arisen, due to the frequent requests for investiga- tion and advice on matters other than telephone broadcasting, orig- inally the committee's sole function. Extension of activities is understood to have been generally approved by the different departments so as to cover the subject of radio communi- cations, and the matter is now be- fore the Secretary of Commerce for further action. It is quite probable that this committee will eventually become the statutory advisory com- mittee provided for in the radio bills sponsored by Senator Kellogg and Congressman White. Activities of the committee to date have made possible the broad- casting of several interesting pro- grams from NOF, the Naval radio station at Anacostia, which is pri- marily the experimental radio sta- tion of the Navy's Bureau of En- By Carl H. Butman gineering. The Anacostia station, however, cannot carry the load and does not operate on Saturday after- noons, due to other official duties. As soon as arrangements are com- pleted, all radiotelephone broadcast- ing for the government will be transferred to the big Arlington sta- tion. Origin of Interdepartmental Committee Last spring, when the popular de- mand for broadcasting reached its height, so many official and semi- official requests to use NOF were made of the Naval Communications Service that Secretary Denby could not grant them all ; in fact, he final- ly ruled that only official messages could be transmitted. At one time, NOF was closed to all except the highest governmental officials. Sug- gestions that an interdepartmental committee be appointed to pass on broadcasting and supervise its op- eration, made by Secretary Hoover, therefore, were welcomed by the Navy Department. The committee began to function on June 1. Mat- ter submitted for broadcasting is inspected and methods of operation arranged by subcommittees which attend to all details, determining the value and demand for particular broadcasts. Applications for broadcasting by the Interior, Agriculture, Labor, Treasury, Commerce, and War De- partments have been approved by the committee and fixed schedules, giving each applicant a maximum service of three fifteen-minute pe- riods each week, have been put in operation. Many listeners - in throughout the country have un- doubtedly heard the evening lectures and band music over the NOF phone on 412 meters. The Government's Schedules On Monday, Tuesday, and Thurs- day evenings, the Treasury Depart- ment broadcasts deal with the activ- ities of the Public Health, Internal Revenue, and Savings Bureaus. The Commerce Department's schedule on Tuesday and Thursday evenings includes information on foreign and domestic markets, trade news, and fisheries. Talks on immigration, women's activities and child welfare are made on Monday, Tuesday, and Thursday evenings by officials of the Labor Department. The Interior Department furnishes lectures on education and mining on Monday and Thursday evenings and Tues- day afternoons. Information per- taining to crops and weather is transmitted every Monday, Tues- day, and Thursday evening by the Department of Agriculture. Officers of the Department of War will shortly broadcast a series of talks on military activities and recruiting on Monday evenings. Sometimes special broadcasts are arranged for national associations, such, for ex- ample, as the series of speeches on Naval Activities by officers of the Navy, requested by the American Marine Association during its ex- position in New York. The evening programs are so grouped as to make a compact schedule and not interfere with private broadcasting. Each week the programs will be an- nounced by the Navy Department. Arlington Chief Broadcasting Station on Two Wave* The opening of NAA, Arlington,, as the official government broad- casting station, has been delayed due to difficulty experienced in operat- ing on the lower governmental wave-band designated for telephone broadcasting. Very soon the Ar- lington station will open two tele- phone broadcasting circuits. It is a very busy station and it is necessary to operate several circuits simul- taneously without interference. NAA's new broadcasting telephone set of 750 watts, recently installed, operates very successfully on the 2050-meter wave telephone circuit, using the main antenna, but does not give good results on the gov- ernment's 490 wave due to reactions between other sets when in use. For this reason, the subcommittee on technical matters has been requested to consider the use of a wave length of 430 meters in this work. If it is approved, special permission will be requested of the Department of Commerce for its use, since it lies in the band assigned to private and toll broadcasting. The lower wave- length is believed necessary so that the service will be available to the people who do not own sets capable of picking up the long 2050-meter wave. Code Broadcasting Extensive Telephone broadcasting for the departments is not the only work handled by the Naval Radio sta- tions ; many messages are broadcast also in telegraph code. NAA car- Digitized by Google

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RADIO WORLD 9 Transmitter That Slips Over the Head Bv S. R. Winters THE multitude of instruments in the cockpit of a modern airplane is graphically pic- tured in a recent diagram indicating that the pilot must manipulate or watch forty units of apparatus. The use of radiotelephony and radio- telegraphy in aerial navigation has enlarged the mass of instruments and controls, this communication service including a radiotelephone transmitter, radioreceiving tuner, wireless amplifying switch, radio- tuning condenser, wireless transmit- receive switch, radio-receiving hel- met, telegraph key, and radio direc- tion finder. Obviously, then, the hands of the pilot are never off duty. Since the control levers for the actual manip- ulation of the air-going machine are likely to monopolize his hands, the use of the radiotelephone is possible while the pilot fingers with the throttle of the engine or other mass of instruments of the aircraft proper. Once the telephone receiver is placed directly over the ear canals, and the telephone transmitter is ad- ( Continued from preceding page) ries ten telegraph broadcasting schedules daily, totaling thirty hours each week and comprising, chiefly, quotations on foodstuffs for the De- partment of Agriculture approxi- mating 35 per cent of its day's work. NAT, the Naval station at New Or- leans, broadcasts two schedules a day, aggregating four hours a week ; the Great Lakes station, NAJ, car- ries eighteen daily schedules, con- stituting thirty-six hours a week. In addition to this matter, twelve Naval stations broadcast two time- signals daily; twenty carry hydro- graphic information ; thirty-seven transmit weather forecasts ; and six broadcast press matter. Sandwiched between these many schedules, the Navy carries on its own official com- munications, as well as many for the State Department, to ships and for- eign stations, and is busy with ex- periments. A glance at the operating sched- ule of any governmental radio sta- tion will explain why the govern- ment requires the service of the In- terdepartmental Committee in an effort to simplify and standardize government broadcasting. Uncle Sam is not only generous with his information but he is also generous in his means for transmitting it to the country at large. justed in front of the mouth, both the transmission and reception of communications may be negotiated while the thumbs and fingers are engaged in controling the fortunes of the airplane. The accompanying photograph herewith shown illus- trates a type of radiotelephone transmitter and receiver which snugly fits over the head of the pilot. Contrary to the common system of transmitting wireless messages from ground stations, the hands are absolutely relieved from holding the telephone and they may be employed in making adjustments of the wire- less apparatus proper or in manipu- lating the control levers of the fly- ing machine. The helmet is made to The above photograph illustrates a type of radio- phone head gear, con si sting of a microphone aad a set of ear pieces, which fit' snugly over the head. This is a marked improvement fa radio for operators who work aboard airplanes. It la .possible for the operator to manipulate the con- trols, dials, direction finder, and key without holding • microphone, which had to be done prior to the use of this device. The microphone is so adjusted before the speakers mouth that he can use it without bonding his head. Close Inspection show* that It ia not far from the lips of the operator. Voice teste have indicated that indistinct transmission of speech is produced when the operator wears the transmitter too far from order ; that is, each unit is designed for an individual wearer and the owner is cautioned not to loan it to others. The telephone receiver is adjusted directly over the ear canals and is fitted thereon snugly as a means of excluding vibrations of the airplane engine and other noises foreign to the incoming wireless signals. The telephone transmitter is so adjusted in front of the mouth that the wearer can use it without caus- ing him to bend his head. Qose in- spection of the photograph illustrat- ing this type of telephone-transmit- ting device shows that it is not far removed from the lips of the op- erator. Voice tests have indicated that indistinct transmission of speech is produced when the pilot wears the transmitter too far from his lips. This design of telephone trans- mitter may be conveniently em- ployed for intercommunication be- tween two airplanes, or a squadron of flying machines, or between air- craft and wireless stations on the ground. When used in connection with the transmitting circuit of SCR-68,1 a popular radiotelephone set of the Signal Corps of the United States Army, it operates thusly : If no voice vibrations are impinged on this transmitter, the potential of the modulator tube grid remains constant. Consequently, there is no fluctuation in the electric currents of the plates of the two electron- tubes. However, when the pilot im- presses his "gift of gab" on this tele- phone transmitter, a pulsating elec- tric current is caused to flow in the primary circuit of the input trans- former. This is the resultant action of the transmitter, which impinges on the grid of the modulator elec- tron-tube an alternating or varying potential electric current following the modulation of the voice. Such variations cause corresponding changes in the electric current per- mitted to get into action in the plate circuit of the modulator electron- tube, and, therefore, in the plate cur- rent of the oscillator-audion bulb. Finally, these variations find their way into the amplitude of the oscil- lations in the circuit of the antenna. Consequently, the electro-magnetic waves radiated by this telephone- transmitting outfit, instead of being of constant amplitude, have an en- velope reproducing the pulsations of electric current m the telephone- transmitter circuit. The electric waves are modulated to the speech. Digitized by Google

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10 RADIO WORLD Broadcasting God's Word to Millions IN the Beginning God," the first four words in The Holy Bible, was the text chosen by Reverend Ernest M. Stires, D.D., for twenty- one years rector of the Saint Thomas Episcopal Church, Fifth Avenue, New York, for his sermon, "The Inevitable Faith," which was the vital part of the first church service to be broadcast from a church edifice in Greater New York. Dr. Stires became a radio enthusi- ast last winter after conducting a radio chapel service in WJZ's broad- casting studio in Newark. Various members of the Saint Thomas's par- ish who were out of town, as well as others, telegraphed, telephoned or wrote about the helpfulness of the service and the clear reception. The request was then made by the West- inghouse officials that they would like to broadcast services from the Saint Thomas Church. The sugges- tion was favorably received by Dr. Stires as he was overwhelmed by the immediate response of the in- visible audience. The Saint Thomas Church is con- By Peter Gray sidered by architects to be the finest example of Gothic architecture of very recent construction. The in- terior of the church with its won- derful pillars, beautiful pulpit, and exquisite altar and reredos is almost beyond description. A sound-proof brick ceiling makes the acoustics of the Saint Thomas Church almost perfect. The microphones are hid- den so as not to detract from the church services. One is on the pul- pit, near the Bible, for broadcasting the sermon, one at the lectern for the reading lesson, two on the chan- cel for prayers and solos, two at the altar for prayers, one on the bal- cony for the organ and choir, one in the hall for the processional and opening prayer and one for WJZ's announcer. Dr. Stires in a/ introductory way in the second service to be broad- cast said the Saint Thomas Church is much pleased and benefited by the instant expression of apprecia- (C Kadel & Herbert) Part of the radio equipment of St. Thomas Church, New York. Note at riant ordinary with apodal (C. Kadel & Herbert) Dr. Ernest M. Stires in the pulpit of St. Thomas, New York, delivering a sermon by radio. Note the microphone on the lectern. tion of the great world outside of the parish and that if any opposition had existed (there was none by the parish), it would have been dispelled by reading the letters piled upon his desk — some came from those who were ill for years and never expect to leave their homes, who said they were benefited and helped and were grateful ; a group around a receiving set took up a collection and sent $11.25 to help defray the church ex- penses. A suburban resident, who used to attend church regularly, was work- ing on his auto and, grease be- smirched, listened in during the wonderful service, and did not feel free to break the silence of his home during the Communion any more than he would in church. Others stated that it was their habit to spend Sunday morning playing poker with friends. Now when 11 o'clock comes around, the cards are cast aside and the radio receiver set to work. And so with pipes alight they follow the service. Two in- stances of lazy ways to go to church but far better than not going at all. It was not many months ago when there was a great diversity of opin- ion in religious circles about the propriety of broadcasting church services as it seemed almost sacri- lege to broadcast prayers and hymns. That was before the first experiment was made, in the history of radiotelephony. Digitized by Google

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RADIO WORLD 11 National Radio Week Is Grip- ping the Entire Country WHAT it IS — NATIONAL RADIO WEEK is a move- ment to popularize radio, to double the number of broadcast listeners, to show the progress made thus far in broadcasting, to reveal new possibilities, to kindle the spirit of radio in as yet unresponsive breasts. . What it is NOT— It is NOT a movement by any one organization. It is NOT a manufacturers' drive. It is NOT intended to be anything but a thoroughly unselfish, co-oper- ative effort, national in scope, ex- haustive in material. When it is to be held — December 23 to 30 (inclusive) this year. The campaign is being directed by an executive committee, of which f. Andrew White, editor of "The Wire- less Age," is chairman. Others on the committee are: H. Gernsback, editor "Radio News"; Arthur H. Halloran, editor "Radio" ; Roland B. Hennessy, editor Radio World; Laurence Nixon, editor "The Radio Dealer"; and Arthur H. Lynch, treasurer, editor "Radio Broadcast." Headquarters — NATIONAL RA- DIO WEEK headquarters are at 326» Broadway, New York City, N. Y. What is to be accomplished — Every listener will endeavor to in- terest one person into a radio fan. This will double the number of broadcast listeners. Programs from every station in the country, spe- cially prepared to fit the holiday season and the spirit of the week, will be sent out on the air. Sport- ing events, operas, jazz bands, speeches, and other particularly in- teresting programs will fill the air. Nation-wide broadcasts of a single event to be heard in every section of the country at once will be made. * * * Country-Wide Words of Praise The following additional acceptances of places on the general committee, and ex- pressions of approval for the campaign, have been received: "Radio Journal," 113 Stimson Building, Los Angeles, says: We are glad "to put our shoulder behind National Radio Week. Our new editor, K. P. Frederick, is lining up local news- papers. Our general manager, Hugh Harlan, is getting support from local driers. Mr. Frederick accepts the honor ">f being on your committee. * • * "Radio Topics," Oak Park, Illinois, says: We shall be glad to co-operate with you, and in our December issue there appears a timely editorial. Our January issue, which will be out December 10, will also carry publicity of assistance to the movement We should be very glad to have you include our name on the active press members. * » * "GST," Hartford, Connecticut, K. B. Warner, editor, says: Our December magazine contains an edi- torial in which we have pointed out to our members the idea of doing what we can to boost radio during National Radio Week. ■ I will accept a place on your general com- mittee as the editor of QST. * * * Mr. H. Lewis, "Radio News," Toronto, Canada, says: I will be only too pleased to co-operate with your committee in putting across a "Radio Christmas." I have been playing up this idea. I should be glad to accept a membership on your committee. * » * /. B. Taltavall, publisher of "Telegraph and Telephone Age," 253 Broadway, New York, says: You are at liberty to add my name to your general committee. * * * Frederick A. Smith, editor, "Radio Age," Chicago, wires: Pleased to accept membership on National Radio Week Committee. Will lend hearty co-operation through magazine. The idea is gobd. ' * * * Telegram from "Radio Digest," 123 West Madtson Street, Chicago, Charles F. Smisor editor: ' Count me in ! * » * 5". Gernsback, editor of "Radio News" says in the December issue of his maga- zine: s . December 23 to December 30, inclusive, is to be the first National Radio Week suggested originally by Mr. Roland B* Hennessy of New York City. During ' that week every radio enthusiast sho-ild °li..t0 ^m\' ta,k> dream and sh>it nothing else but Radio. The object is to acquaint the public at larjre with Radio. "Radio News" has prepared a beautiful colored post card which we shall be glad to send to every one who asks, in any reasonable quantities. This postal card the picture of which will be published in the next issue of "Radio News." is to be sent to all your friends who are as yet Send in your Ideas for the Success of National Radio Week Help to Make It the Big Christmas Event Be a National Radio Week Booster not interested in Radio, inviting them to come and see your station, or any first- class station of which you know. This is a preliminary announcement, and we shall have more to say abtmt Na- tional Radio Week in the January issue. » » » "The Evening Journal," New York, says: The great part which radio communi- cation has taken in the dissemination of education and entertainment and its ser- vice_ as a means of interchanging infor- mation is to be demonstrated by a co- ordinated program of the radio interests, in a country-wide undertaking to estab- lish a National Radio Week as an annual event. The effort to establish National Radio Week as an annual institution is backed by co-operative effort on the part of the newspapers, the radio press, manufac- turers, dealers, amateurs and the great army of broadcast listeners. The tentative program is arranged for the week December 23 to 30, inclusive. It is a most comprehensive plan to pop- ularize radio with the public, and while only a general outline of the plan is so far available, it is known that it em- braces programs of national, State and local character in which the 550 or more radiophone broadcasting stations of the country will take an active and important part. Special programs to include the leaders among public officers, statesmen, educa- tors and the musical and entertainment world m general are being arranged, all with the main idea of introducing radio to the uninitiated and firmly establishing it in its proper place as a recognized agency of bringing radio instruction and entertainment into the homes. * * * Under the heading "Hail National Radio Week and Help Put it Over Big," the "Radio Retailer and Jobber" says: The idea was first announced at a luncheon of radio paper editors held at , the Bankers Club, in the Equitable Building, 120 Broadway, New York City, early on a Tuesday afternoon in October last. The innovation was seized upon with alacrity by all present and provision was made for a very formidable and well- balanced committee to sponsor the insti- tution and make of it a crowning success. The broadcasting stations were called upon to transmit the announcement that Kadio Week was scheduled soon to come; thus saving a huge outlay in postage, though extensive circularizing has been provided for. The broadcasting stations have also ?>een. HJ?ed t0 com»nemorate National Kadio Week by particularly notable pro- grams which would prompt listeners-in to look forward to Radio Week as an annual institution. D ^yerv-refort will be made to make Kadio Week a national and not a local- ized innovation. So one and all from coast to coast and from the lakes to the gulf, with Canada thrown in, let us root for Na- tional Radio Week, and let us put it over with a great blare of trumpets, so that it may be a national institution, an annual visitor and a great stimulator of activity in the radio trade fof many years. Digitized by Google

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12 RADIO WORLD Progress in Radio Devices Approximately 3500 Patents Already Granted, 400 of Which Are Held by Fessenden, De Forest, and Stone By B. R. Cummings Radio Engineer, General Electric Company THE fundamental phenomenon which 'is utilized in radio- telegraphy and radiotelephony was first demonstrated by Heinrich Hertz, the German electrician, in 1888, thirty-four years ago. Hertz, at that time, showed that it was pos- sible to radiate energy through free space. He was not interested in ac- complishing results over great dis- tances, apparently not having con- ceived the idea that this phenome- non could be utilized as a method of communication, and his tests were carried on only over distances up to approximately 300 feet. In fact, Hertz deliberately avoided using an earth connection in his ap- paratus, which would have immedi- ately increased the distances over which he worked, believing that this would detract from his demonstra- tion of the transfer of energy through space and that it would ap- pear that the energy was being transferred by the conductivity of the earth. He was interested only in a pure demonstration in physics. . It is of interest to note, in com- paring Hertz's equipment with mod- ern radio apparatus, that his re- ceiver consisted only of a single loop of wire which included a minute spark gap, and that his indication of the transfer of energy through space was the spark which jumped this gap when the so-called "Hertz ian Oscillator" was in operation. His receiver, or "indicator," there- fore, was extremely crude as com- pared with modern radio-receiving. The Hertzian oscillator remained a laboratory instrument for a num- ber of years, and was used only in connection with experiments in physics. In 1894, Marconi, who was a wealthy young man with a scientific training, saw in the Hertzian oscil- lator a possibility of developing a new method of communication which would permit communication being carried on over areas previ- ously considered impassable. In- stead of avoiding the earth connec- tion, as Hertz had done, he used it both as the transmitting and receiv- ing stations and was immediately able to secure an indication of the transfer of energy over much greater distances than had been realized by Hertz. The years immediately following 1894 were marked with intensive de- velopment on the part of Marconi, both of transmitting and receiving equipment, with gradually increas- ing ranges, until, on December 12, 1901, he succeeded in transmitting the letter S across the Atlantic from England to Newfoundland. While Marconi, since that time, has contributed greatly to the ad- vancement of the radio art, his greatest work may be said to have been completed at that time, for he had shown that the Hertzian oscil- lator, which had previously been considered only as an interesting laboratory experiment, could be used in establishing communication over great distances, and that the widespread use of this system de- pended only upon the further per- fection of the apparatus utilized. This accomplishment attracted the attention of scientists in all parts of the world toward "wireless," as it was then called. In the years im- mediately following, tremendous strides were made in improving the sensitivity of receiving equipments and in increasing the power radiated at the transmitting station. The individual accomplishments in radio from this point on are some- what hard to define, although sev- eral of the outstanding contribu- tions to the art can be touched upon. In 1884, Edison, and several years later, Fleming, discovered that it is possible to pass an electric current from a hot body to a cold body in a vacuum. This phenomenon was investigated by Fleming for a num- ber of years. After he discovered that such a device would pass cur- rent in one direction only, and was, therefore, a rectifier, he secured a patent on it in 1905, the device be- ing known as the "Fleming Valve." This valve was utilized in radio-re- ceiving circuits as a detector and was a tremendous improvement over previous forms of detectors. Shortly thereafter, Dr. Lee de Forest obtained a patent on a de- vice which he called the "audion" and which was essentially the Flem- ing valve with a third electrode by means of which it was possible to control the current flowing in the tube. Strangely enough, in spite of the progress made in these devices, which are grouped under the head- ing of "vacuum tubes," compara- tively little was known of exactly what takes place in them. A num- ber of years elapsed before their functioning had been analyzed. In 1915, Armstrong made known 'what has since come to, be called the "feed-back" circuit, by means of which the detection and amplifica- tion of received signals, by a single tube, was made possible, and also by means of which the three-element vacuum tube could be made tp func- tion as a generator of alternating current, making possible the mod- ern vacuum-tube transmitter. Although radio broadcasting is a recent development, radiotelephony was first accomplished as far back as 1905, and the broadcasting of music was successfully carried on by de Forest as early as 1914. Prac- tically no interest was shown by the general public in broadcasting at that time, and his concerts were dis- continued. Broadcasting has also been carried on, although in the Con- tinental code, by the Navy Depart- ment station at Arlington, Virginia, which, since 1915, has been trans- mitting time signals, weather fore- casts and news events each night after 10 o'clock. It has been from Arlington's transmission that ships at sea have been able to print daily newspapers. To indicate the great nunlber of devices and circuits which have been developed for radio communication, approximately 3500 radio patents have been granted up to the present time. Naturally, some means have been much more prolific in this re- spect than others; and three men. who were most active in the early days of radio, Fessenden, de Forest, and Stone, hold among them a total of nearly 400 patents. And yet, the tremendous amount of research and development work which has been done in advancing the radio art has only served to in- dicate fields and applications for this method of communication which have as yet been unexplored. It seems assured that radio will event- ually find its place as a public utility and be utilized to an extent far sur- passing any of the other existing methods of communication- Digitized by Google

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RADIO WORLD 13 The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks /S all electricity made up of elec- trons? All electricity is made up of elec- trons. You will get a correct idea of electricity if you try to visualize it as being made up of electrons. Every- thing contains electricity; in other words, everything contains electrons. ' * * * What are electrons? An electron is a minute negative charge — it is but the smallest fraction of an atom. A negatively charged body has more than its usual number of electrons. A positively charged body has less than the usual number , of electrons. * * * How do these electrons flow? Electrons flow along a conductor when that conductor connects objects, or points, which do not have the same share of electricity, not the same amount of electricity. One body may have a greater amount of electricity than another and yet have the same share in the same way as if a grown man and a two-year-old child were sharing food. The man would have a greater amount of food than the child, and yet he would have shared it with the child. In electricity the size, shape, and other elements of a body determine what the share should be. • * * How many ways are there in which an object may have a different share of electricity? There are five ways in which an ob- ject may ''have a different share of electricity. One object may have more than its usual number of electrons and another object less than the usual num- ber. Electrons will travel until both have the same share. Still there are four more ways in which an object may have a different share of elec- tricity. Years ago, before much was known about electricity, it was under- stood that something "flowed" along a wire. The men studying electricity then agreed to say that it "flowed." They had an even chance of being right, but they made the wrong guess. The word has not been changed. To do so now would only create confusion. In a similar sense, we state that the sun rises. It is a stationary body. Tile earth moves. However', electricity "flows" along a wire from one end to another. The force of this is called "voltage." What is voltage? Voltage between two points meas- ures the effort which the electrons make to move from one point to an- other. The effort which electrons make to move from one point to an- other depends on the difference in the proper share of electrons in excess of the other. The greater the difference in the share of , electrons, the greater the voltage. However, we do not measure voltage by saying that one point has a certain number of elec- trons in excess of the other. It is measured in volts. This is somewhat Schematic diagram of a conductor aeraaa a ptas, Its duty in radio I* to carry tho polo to polo. la radio work this is torraod a abort circuit* Drawn by Lym Brooks. similar to the fact that we do not buy beans by prdering a certain number — we buy them by the quart. When you speak of voltage you must have two points in mind. Voltage is an expres- sion of the effort made by electricity to get from one point to the other. It is measured in volts. * * * How do the electrons travel? Electrons travel, or try to travel, from the point which has the greater share of electrons to the other point. As the point which has the greater share of electrons is negative ( — ) and the other point usually positive (+), the electrons travel, or try to travel, from negative to positive. The cur- rent is said to flow in the opposite direction — that is, from positive (+) to negative ( — ). * * * What is necessary to produce an electric current? If we can keep a point so that it will always have more than its usual number of electrons ( — ), and an- other point that will always have less than its usual number of elec- trons (+) ; and if we connect both points by a conductor, we will have the condition necessary to produce an electric current. How to Determine a Detector Vacuum Tube TO determine a detector tube from an amplifier can be ac- complished only by experiment. Place the detector tube in the am- plifying socket and use from 45 to 60 volts of plate potential. Turn on the filament current and pay close attention to the results. If the tube should happen to turn blue, turn off the current at once. This test will show that this tube is a soft tube and should be used as a detector and for detecting purposes only. In case the blue glow is not present, it is a sure sign that this tube is an ampli- fier of the hard-tube class. What Is Meant by Coupling THE object of loose coupling is to eliminate the effect of inter- ference by loosening the coupling between the two coils, the primary and secondary. It has been found in practice that when the primary and secondary circuits are in reso- nance with each other, the primary and secondary coils may be sepa- rated quite a distance and signals still be recorded in the telephone re- ceivers; whereas signals that are not in resonance with the circuits will be eliminated by widening the coupling between the primary and secondary. TheTicklerCoiFsUse THE tickler coil is a coil of wire placed in inductive relation to the primary and secondary circuits of a receiving set. The tickler itself is in the plate circuit of the vacuum tube and affords a feed-back system that produces regeneration. The function of the tickler is best ex- plained by describing what happens if you take the telephone receiver from the hook when the bell is ring- ing and then place the receiver to the transmitter. The result will be a continued "howling." This is re- generation. In a radio circuit, the tickler coil produces regeneration. The Radio Primer has (wen published rafobrly in. RADIO WORLD sine* issue No. 1, will be a regular departman order to ins tract and aid the thousands of amateurs who joining the ranks of Digitized by Google

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14 RADIO WORLD Radiograms Latest Important News of Radio Garnered from the World Over, and Reduced to Short Wave-Lengths for the Busy Reader. MAJOR GENERAL JAMES G. HARBORD, deputy chief of staff of the United State* Army, on his retirement will become president of the Radio Corporation of America. General Harbord was elected head of the Radio Corporation at a recent meeting in New York. His retirement from the Army will be effective December 29, Secretary Weeks announces, and he will assume his new duties on January 1, 1923. Edward J. Nally, president of the Radio Corporation, it is announced, has been elected to a new office — that of managing dire :tor of International Relations, with headquarters in Paris. * * * The Mexican Government is about to receive four p .werful radiotelegraph sets, which are to be presented to the republics of Guatemala, Honduras, Costa Rica, and Nicaragua in accord- ance with the decision of the president of the Republic. * * * The London Free- Press of London, Canada, recently opened its broadcasting station. Its call letters are CJGC and its wave is 430 meters. At present its power is derived from two 50- watt oscillators. * * * Probably no other broadcasting station in the country can claim the distinction recently achieved by station KSD, San Francisco. A concert was sent out_ from this station, which was heard in every State in the Union. * * * A radio message, picked up at the Santiago Station of the Naval Wireless System and relayed from San Francisco, pur- porting to come from Hilo, Territory of Hawaii, told of an earthquake and tidal wave there. Efforts to communicate with the Hilo Radio Station, operated by a private concern, later were unsuccessful, but radio men declared it was not usual for that station to communicate direct with mainland stations. * * * The completion of the new radio station at La Prairie, Canada, will connect Sydney, Australia, and London. * * * The United Fruit Company has announced the inauguration of a free medical radio service from its hospitals in the various countries of Central America and from its passenger steam- ships to all ships at sea. This service is to be available without charge to ships of all nationalities through the following radio stations operated by the United Fruit Company and the Tropi- cal Radio Telegraph Company: New Orleans, WNU; Burwood, Louisiana, WBW; Fort Morgan, Alabama, WIO; Swan Island, US; Tela, Honduras, UC; Puerto Castilla, Honduras, UA; Teg- ucigalpa, UG ; Port Limon, Costa Rica, UX ; Almirante, UB, and Santa Marta, Colombia, UJ. * * * To London and back, by radio, in 45 seconds! To Berlin and back, by radio, in 2 minutes and 40 seconds 1 These were the records made at the Engineering Societies Building, 26 West 39th St: ?et, New York City, on Wednesday evening, November 22, during a discussion on radio by David Saranoff, vice-presi- dent of the'' Radio Corporation of America. "How's, the weather?" was the query flashed across the Atlantic. Within three minutes the members of the society heard the dot and dash replies hurled back through the night from three countries of Europe. Within forty-five seconds London's answer came in: "Raining, mild." Ten seconds later came the reply from Norway: "Overcast, mild." France was third with: "Lovely weather," and Germany came last, two minutes and forty seconds after the question. She answered, "Gloomy, cold," and then added, "Greetings." A new development in_ radio, which Mr. Saranoff predicted would come soon, he described as the "wrist- watch wireless set or radiolet." "Such a set could be carried easily on the person," said Mr. Saranoff, "and signals could be received from stations twelve or fifteen miles distant, thus a man could receive in his vest pocket market reports, weather reports and details of championship games." * * * Amateur long-distance radio records were shattered at the radio station of Hiram P. Maxim, president of the American Radio Relay League, when a radiogram was sent to Clifford Dow, Waikiki, Hawaiian Islands, and the answer was received in 4 minutes and 18 seconds. The radiogram was relayed at Sleepy Eye, Minnesota, by Lloyd V. Berkmer. The distance from Hartford to Sleepy Eye by air line is about 1,200 miles, and thence to Wailuku 4,000 miles. * » * Cavalry Church, Pittsburgh is using radio-receiving sets as an extension work. — "Our parish is now doing organized work by wireless," said Dr. E. J. Van Etten, the rector. "We now have receiving sets. On certain nights, the Church Home is hearing our service through one of them. Two invalids are hearing these services through smaller sets in the hands of the new Calvary Radio Club. We send greetings of others who every Sunday night hear these sermons." * • • For the first time symphony music by a large orchestra has been broadcast by radio direct from the theatre.— That dis- tinction falls to the Capitol Grand Orchestra, New York, whose performance of Richard Strauss's symphonic poem "Fun Held- enleben" was broadcast recently. The American Telephone and Telegraph Company, which perfected the sending, pro- nounced the achievement successful in every respect. The music was heard over a radius of 1,000 miles and over 600,000 radio sets caught the concert. The feat was accomplished by a highly sensitized microphone suspended form the roof, by which the sounds of the music were amplified and carried over equalized telephone wires to station WEAF and then sent. * * * Radio communication is successfully used on airplanes to communicate to military bases from the air or enemy territory. The apparatus comprises a small sending and receiving station of light weight. Remarkable success has been attained over long ranges with radiotelephone, radiotelegraph, and direction- finding equipment. The receivers are provided with sound protectors, but receiving is less successful than sending be- cause of the propeller noise. This defect has been overcome to some extent by using sound insulated telephone-headpieces the aerial is generally, mounted on the planes and a counter- poise or additional aerial is used instead of a ground * * * The first dress rehearsal of a theatrical performance to be broadcast by radio is also reported.— "This Little Kangaroo," the new musical comedy with James T. Powers, has been ar- ranged was sent out by WJZ from the Morosco Theatre, New b 22 ltnportant radl° event took Place at S:30 p. m. No- Getting Ready for the Big Show SH. FAIRBANKS, who managed the . recent successful Radio Show in Boston, has been retained as advisory director by the management of the Amer- ican Radio Exposition. This apportion- ment will be held in Grand Central Palace, New York, December 21 to 30, inclusive, and from present indications will far sur- ?ass any radio display of the past. Mr. 'airbanks will take charge of exhibits, the appointment of space, and other de- tails of staging the show. L. S. Byers, executive secretary of the committee in charge of the show, will continue with the program of organization. A series of novel and sensational features are be- ing worked out at present to make the exposition unusually interesting to the general public, as well as the fans and those unfamiliar with radio. A number of new exhibitors contracted for space during the past few days. These include the Electric Storage Battery Co., A. H. Grebe & Co., Jewett Manufactur- ing Co., Newark, N. J., and the Burgess Battery Co. Exhibits are promised by the Western Electric Co., Inc., The Radio Corporation of America, and the National Carbon Co. For economical reasons, practically all industries holding yearly expositions have learned that the East will support only one exposition a season, with per- haps one in the Middle West and one in New England. In view of the importance of the metropolis as an industrial and export center, the numerous manufac- turers exhibiting are talking co-operation in one big annual New York event, staged in a manner that will mean profit to man- ufacturers and dealers alike, and at- tractive to the public. Held in Radio Stock Deal MRS. MYRON CLEVELAND HAR- RIET SIMS, a stock broker, al- leged to have sold stock in a radio com- pany under misrepresentations to women investors, was held in $7,500 bail for th« Grand Jury when arraigned before Magis- trate Joseph E. Corrigan in West Side Court, New York. Mrs. Sims denied the charges. Digitized by Google

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RADIO WORLD 15 Radio and the Woman Crystal D. Tector ONE of the leading doctors of New York City took me through his hospital for children the other day He is the head physician and guiding spirit of this institution; and he has decided to put a radio set in every room — not one set in the build- ing, but, actually a set in every room I He said that he had read so much about radio- being such a wonderful source of entertain- ment that he decided to see if the reports were true. He visited several institutions where radio is used as a means of entertaining the inmates, and came to the conclusion that the reports were in no wise exaggerated. • * * I was called in because he really knew no one else who might give him some advice. Immediately he decided that radio was a necessary element of his institution. He rushed to a newsstand, he says, and purchased a copy of Radio World. He opened the paper to my page, and, he continued, "as a matter of luck, I sent for you." * * * I gave him the names and addresses of several experts who will fit him out — who will install in each of the sixty rooms of his hospital just what he needs in the way of radio reception. But this fact is neither here nor there. It is a purely commercial matter in which I am not interested. I am only thinking of the big, human, charitable idea back of it all. I am extolling this man for thinking of someone else — of his willingness to go to any expense, as he told me, that the little sufferers in his care might have some entertainment to relieve their hours of convalescence. Children — and grown-ups, too, — have suffered from the beginning of time; and as the world has progressed, and, little by little, efforts have been made to relieve their suffering. Here, in the midst of the first lustrum of this benighted century, comes the happiest method of all — the bringing to little bedsides where patient sufferers lie, the wonderful and fascinating things that come over the ether. I think that the success of this doctor's experiment will urge other institutions to follow suit. I make the prediction that it won't be long before every hospital in this country is' in- stalled with radio — and that radio will be as necessary to it as the doctors themselves. • * * And as the gladsome time of the year approaches, what can be of greater satisfaction to this man of medicine, this eminent diagnostician, than the fact that he is not purchasing a few trinkets and toys that will be cast aside as soon as they are 4>roken — that be is not doing something that will please only his little patients of today, but that he is building, for all time, for the unfortunate children of the future who will come into his care. And as radio is improved and its scope becomes wider, there will be special broadcasts for hospitals — stories, and songs, and messages of cheer, and church services for all — young and old — who are temporarily incapacitated. • * * More power to this good doctor. In reply to several correspondents : It is not difficult — or, it should not be difficult — to start the nominating for the offices of a Na- tional Radio Week committee. You say that when it comes to nominating a chairman, no one seems inclined to start the ball rolling. Why not all speak at once? Now, I don't mean to be funny; I am just trying to be practical. Out of this method, some one is bound to be heard and the temporary chairman, if she has any pep, is bound to recognize one of the speakers. Mrs. A. H. LM Walla Walla, Washington — By all means give your husband a radio set for his Christmas. I assure you that radio is not "wholly a man's field," as you write. I cannot praise it enough as a source of entertainment for women as well. And as for the children — well, if your boy "has not taken to it as yet, and seems wholly uninterested,'* all I can say is that something is wrong somewhere. You get the set and, about a month later, write me what effect it has had on the family. * * • Miss Hattie Kane, Harrisburg, Pennsylvania — Your idea of a red-white-and-blue ribbon with the letters N. R. W. thereon, to be worn during the big week is splendid. But why not the word Woman Electrical Engineer Constructs Own Radio Sets (C Kadel & Herbert) Miu Elizabeth Martrodge, of Exeter, England, to one of the few women electrical engineers In the world. Aside from this distinction, she to the inventor of a number of electrical appliances, and, to-day, is undertaking the installing of electrical lighting seta in country houses. However, sine* radio came into prominence in her country, she has "fitted up," as they term it on the other side of the Atlantic, a number of radio sets for "listeners In." Miss Martrodge is, perhaps, the pioneer woman radloist of Great Britain. She believes in it heartily and has done much to promote interest in the new science and to give valuable advice in order to help the British Government in Its broadcasting problems. Miss Martrodge la shown in the photograph with her petrol-lighting set— petrol, or , being used there for heating country houses. "RADIO"? You say that the ribbons are to be worn by women. Now, we want radio week to be the means of bringing^housands of fans into the fold and there are many so totally uninitiated that they might think N R W. stood for New Republic of Women, or something like that. With but the one word— -"RADIO" — pinned jauntily to each feminine breast, the big idea is at once indelibly stamped and no time is wasted making explanations. • • * Vast possibilities of radio broadcasting are demonstrating them- selves every day. In fact, every hour brings forth some new achievement for the great invention. For instance the postman delivered, several days ago, the .following letter, which was addressed to the studio manager of WLW, the broadcasting station being operated by the Crosley Manufacturing Company: Studio Manager, WLW Dear Sir: I am sick in bed, and my mother has moved my radio set into my bedroom so I can listen in. I enjoy this very much and sure get WLW very loud and clear. My collie dog likes to listen in, too. Yours sincerely, J. CTYDE FOX. 2640 West Sixth Street, Cincinnati, Ohio. You who are in good health and enjoy listening to concerts, close your eyes a moment and picture this boy who, we have learned, is but 14 years old, lying in bed fighting off an attack of diphtheria and still reaping the harvests of pleasure that WLW is sowing. Also picture this boy's dog beside him, with head phones at his ears, and sharing the enjoyment of his little master. Digitized by Google

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16 RADIO WORLD Latest Radio Equipment Plays an Imp (C. Kadel ft Herbert) (Above) W. F. Bingham, Manhattan manager of the Radio Relay League, who ha* charge of all radlo-meenge traffic in the Second District. To carry on this important work success- fully, a perfect receiving station is essential. On the left of the photograph may be Mr. Bingham's long-wave receiver. On the right is the short-wave receiver and part of the transmitting apparatus. ©Qkt Ksdei ft Herbert) J

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RADIO *WORLD 17 rtant Part in the Service of the World tube ikon in this photograph, ft ft ■do. It ft Um than half tho sfto of tho ant tube," Invented by Dr. Irvln» Langmulr. It has plate, grid, and filamant. It oparatos on a' small dry- dal I that it will bring In signals loud and clear. It was r York radio amateur solely (or experimental purpeoas tn a miniature pocket vacuum-receiver which he is entering ■t. An idea of its small she may be gained by in the earn wonderful miniature radio set— one that may be It wfB fit Into a small kodak case and may ba md carried by the owner on his travels. It has range of about three-fourths of a mQe and a receiving range a. Note particularly the miniature tube and the microphone sauttmg. The dry batteries may he carried in tho camera Mt of the set. Mr. Sterling G. Sears, who built the set, is togranh. He ft talking Into the small microphone that ft L Tate ft another view of the receiving set station In the United States, was established I nam the station was ft Iftte of national stations- Its call to WBV. (Right) The Prince of Wales, now an ardent radio fan, Is broadcasting a message to VMM boy scouts In his country. He ft photographed ■passing Into a field telephone, his words being carried by wore to Marconi, London, and from there broadcast over Groat Britain. (C. Keystone View Co.) (C international News Keel) (Above) The transmitting room of station WWZ, Wanamaker's, Nsw York City. This station which works on a Mt meter wave-length is equipped with a vacuum-tube transmitter of the Western Electric type. The operator Is shown here adjusting the transmitter to i signal strength. On the table ft the power ampUfler and laud speaker. This uses a power voice-amplifier. Without this device success In broadcasting would be quae tionable; but this new device is able to convey, without losing oven the fraction of a sound, music and the human »ists frisu any place where they may he apparatus, where it is generated into n they may he produced to tho fan

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18 RADIO WORLD With the DX Night Owls My Hook-up and How It Works By James A. Merklein, R. E. 2 Megohms ....... \-B-Battery,??t Volts 1 1 1 1 1 ll> — ¥ N the aerial I have, in series, a 001 or *■ 43-plate variable condenser. Next is the coupler, and this must be made by the fan. Take a piece of Formica tubing 4 inches in diameter and 5 inches long, and wind on this 54 turns of No. 20 DCC wire and tap at every 6 turns until 9 taps have been taken off. Very loose coupling must be employed when winding the coupler. Start to wind_ 1J4 inches from one end to allow sufficient space for fastening the brass strips which are about SVi inches long and V2 an inch wide, of 1-16 inch stock brass. A J4-inch hole is then bored » through each piece, % inch from one end, to fit the shafting of the rotor. The next step is the stator or second- ary of coupler. A 3^2-inch wood ball must be used. On this wind 30 turns of the same size wire, placing 15 turns on each half of the rotor. In the plate circuit is a D-L 100 honey- comb coil, shunted with a 0005 variable condenser, and must have the vernier at- tachment plates. This will have to be playedwith, as I have found that this size coil will not work as it should. I have found some coils not rated as they should be. _ In other words, the proper amount of inductance should be between three and six milhenries. Across this is shunted another 0005 condenser of the fixed type. This must be used, as the oscillations from the amplifier tubes are so great that something must be placed before these tubes in order to stop the detector from becoming choked. There- fore, this acts as the stopping condenser. T-l is and must be a U-V 712. Radio Corporation transformer, due to its high ratio which is 9/1 the secondary; or S-2, which is usually marked "G," is in series with a 00025 Dtibilier grid condenser, type 601, with grid leak mounting. The same size is also required for the de- tector. Without the grid mount, use type 600. Across the secondary leads is shunted with a 1-megohm tubular grid leak, (A 2 meg. is shunted across the sec- ondary of the coupler. See diagram), T-2 and T-3 are the usual type 4/1 ratio transformer, but of the standard type. The grid leak on the last step must not be more than megohms. T3- transformer and T2- are coupled. That is, the filament side S-l- is tapped onto S-2 or grid side of T-3-; S-2 of T-l is run to the grid condensor — 00025 — and then to the grid. S-l- of T-3- is then connected to the negative side of the fila- ment. The primary side of T-3 is con- nected to the B battery, as will be seen in the diagram, and must be shunt with a 0005 fixed condenser. Across the phones is a 00025 variable condenser or 11 plate with vernier at- tachment This will give a very fine and exact tuning. A potentiometer is to be shunted, ac- cording to the diagram. Much of the result will depend on this for proper ad- justment. I will be glad to hear from any radio fan regarding the results obtained with this hook-up. Any questions concerning this set will t& cheerfully answered. The total amount of the B battery is 350 volts, having: a 22}4-volt tap and a 90-volt tan, & 350 tap for the last tube. Use a U \ )0 in the detector, U V- 201 in first sten, and a power tube, V-T- 202, or U V-202 in the last step. * * * Mr. Merklein QSL's EDITOR, Radio World— Tn Radio World No. 34, dated November 18, I note that Mr. Walter George McKinley claims that he has me snowed in, but I believe 0002S-*\\ 90 V Tat, Volts „ mm that this letter will find him to be some- what in need of a rowboat. Another thing, WDAP was working on half power. I also would like to impress on him, also, that I am no newly found radio' fan, but an amateur wireless-operator who has been ticking the key for the last six years; therefore, broadcast music is nothing to me, only an aid in my DX experiments. I don't claim any records, and my rea- son for the "rite" up that time was to find out what the other fellow is doing. This we need in order to 'keep radio mov- ing; so let's all get together and make radio a bigger success. The following list of stations were re- ceived QSA through QRN. These tests were made between the hours of 9 P. M. and 3 A. M., from November 3 to No- vember 18: WLAY, Fairbanks, Canada; PWX, Cuba (concert in Spanish); KSD, St. Louis; KFU, Gridly, California (faint); CFCA, Toronto, Canada; KDKX, Honolulu. Please QSL your results on this tuner. — James A. Merklein, Brooklyn, N. Y., I. R. E., Member of the Radio League of America and the American Radio Relay League. * * ♦ Call Set "Freak"; but It Delivers the Goods EDITOR, Radio World:— After reading the results made with some sets, I feel as if I will not be taking too- much of your time in telling you of my suc- cess. I am using a home-made set of one tube built for short- and long-wave re- ceiving. I also have a crystal mounted on panel for code. My inductance con- sists of a primary of 360 turns, No. 24, wound on a tube 5 inches in diameter, Digitized by V^OOglC

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RA*DIO WORLD' 19 {Continued from preceding page) also 90 turns wound on the same tube at ^ and taped every 15th turn for tickler inductance, a 4%-inch rotor, wound with 90 turns of No. 24 on the same end, and in plate circuit on other end of the coil. I have a sliding secondary 4% inches in diameter wound with 320 turns of No. 24 enameled wire. The switches are pro- vided to use either loose coupler, vario- coupler, or both. I have a 23-plate con- denser in aerial circuit, and a small fixed condenser across phones. My aerial is a 3-wire, 86 feet long and 38 feet high. I have heard KSC, San Jose, California; KQA, Denver; the Fort Worth, Texas, "Journal"; WHB, Kansas City, Missouri; CJCE, Vancouver, B. C, and WGY, KDKA, WSB, WOC, and KSD regularly. Some say that my set is a freak; but it delivers, the goods and is always under control. — J. T. Cavanaugh, 1024 Leahy Street, Muskegon Heights, Mich. * * * 83 Stations, His Record EDITOR, Radio World:— From 5 o'clock until 11 o'clock p. m., I average from 15 to 18 stations. Last election night, from 5 p. m. to 3 a. m., I caught 30 sta- tions giving election returns. I keep a map_ and log. My record to date is 83 stations outside of the State of Georgia, including Canada and Cuba. The words and music come in clearly. I operate a one-tube home-made short-wave regener- ative set with vario-coupler and two vari- ometers, mounted on back of panel, and a variable condenser. I also use a 6-wire cage-aerial, 80 feet long, 50 feet high, north and south direction. The diameter of the cage is 12 feet. My lead-in, which is a 6-wire cage, is 50 feet. My counter- poise is a 3-wire, 80-foot, mounted 8 feet from the ground. I invite anyone to write me about my hook-up. — James L. Fischer, 72 Spring Street, Newman, Georgia. * * * Claims the Record EDITOR, Radio World:— I have read with interest the letters from Mr. Merklein, Mr. McKinley and Mr. Miller, each giving thew receiving records on one tube. I think I can beat their records. Using a two-variometer type set, one de- tector tube and 48 volts, I receive the following loud and very clear: WGY, Schenectady, New York ; WDAP, WJAZ, and KYW, Chicago; WOC, Davenport, Iowa; WNB, Kansas City, Missouri; WGM and WSB, Atlanta, Georgia ; NOF, Anacostia, D. C; WJZ, KDKA, WBZ, WOR, WIP, WEAF, WBAY, WHAZ, WWJ, WNAC, WQAA and others in New York State and other States. These are all heard on a 4-wire inverted-L aerial 40 feet long and 35 feet high, 15 feet above a tin roof. With the same set and tube not lit to extreme brilliancy, with no aerial con- nection, only ground connection, I have heard WGM, WSB, WOE, KYW, WDAP, WGY, WJZ, WBAY, EEAF, KFAF and 2X1 very plainly. I think this record can surpass any of those Radio World has published. — E. Sherow, Box 365, Mill- brook, New York. » * * Takes His Set with Him EDITOR, Radio World:— I have been reading in Radio World of the excel- lent results accomplished by other "radio- phans." Messrs. Merklein, Brooklyn, New York; W. G. McKinley, Bayonne, New , Jersey, and E. L. Miller, Chappaqua, New York, seem to be doing very well, in- deed. I am a resident of Brooklyn, down here on business, and have my set with me. It consists of the conventional vario- coupler, variable condenser, variometer, detector and one stage of a. f. I only use 22y2 volts for the detector and 45 on the amplifier. Why waste the power? I am surrounded by high hills. My aerial is a single wire, 115 feet long and only 14 feet above ground. A 440-volt lighting line passes 5 feet above it, and a 5500-volt power line is less than 50 feet away. The aerial also passes close to the roof of an electrically operated printing plant, and is parallel to a 220-volt light line and a couple of telephone lines. In spite of these handicaps, my set "does its stuff right niftik" every day and night. I have received concerts from more than 45 stations in 17 different States and Canada. These stations are from 59 to 1169 miles distant (accurately measured air-line). My best reception is from sta- tions upwards of 560 miles. On the night of November 9, I received music from 18 stations in 13 States from Massachusetts to Minnesota, and from the Mississippi Valley to Texas. Here are some of the fellows I hear every time we are on the air together: KDKA, Pittsburgh; WOO and WIP, Philadelphia; KSD, St. Louis; WOS, Jef- ferson City, Missouri ; WDAF and WHB. Kansas City, Missouri; WWJ, Detroit; KYW, WDAP, and WMAQ, Chicago; WBAP, Fort Worth. Texas ; WLAG, Min- neapolis; WFAC, Superior, Wisconsin; WKN, Memphis, Tennessee; WSB, WGM and WDAJ, Atlanta, Georgia; WOC, Davenport, Iowa; WGY, Schenectady, New York ; WGT, Medford Hillside, Mas- sachusetts; WBZ, Springfield. Massachu- setts : WNAC, Boston ; also WJZ, WEAF and WOR, the ones I hear most while at home in Brooklyn. I can easily tune out KDKA which is only about 59 miles away and very pow- erful. Frequently I use a small funnel for a mesraohone loud-speaker while receiving WWJ. and WHB. My set is home made (by myself) and I have not yet soldered the connections. Some nice cold evening I hope to hear something from the Pacific Coast I Until them. — John S. Frampton, Spangler, Pennsylvania. * * * Good Detector-Tube Reception EDITOR. RADIO WORLD :— I get KHJ (Los Angeles, Cal.) regularly, having had them five evenings this week; DNA of Denver, also Winnipeg, Canada, and Havana, Cuba. I receive many other stations at 1,000 miles and over. All this is being accomplished while experimenting on a detector tube without amplification. I don't just get them and hear the call, but I get as much of the broadcasting as I care to hear. Without amplification. I think this record is pretty good for de- tector-tube reception.— H. S. Rahiser, Box 43, Crafton Station, Pittsburgh, Pa. Wo Wirdess 'Jie&ivinef ^ set qjmplele withoufit. Harlem Club Wants Members THE Radio Club of East Harlem was organized September 20, 10 2, the fol- lowing officers being elected: Harold Itzel, president; John N. Itzel, secretary; John D. McEvily, treasurer; WHliam Bog- del, instructor. The main o^ett of the club is to bring together radio amateurs- living in the district from 125th Street to ?6th Street, east of Fifth Avenue. The present total membership of the club is fifteen, and as the membership is limited to thirty-five, there is room for twenty more members. Write the sec- retary, John N. Itzel, 175 East 111th Street, New York City. ^GREATEr\Hadio Christmas THIS year the message of Christmas will flash one inspiration over all lands and to all peoples — no frontier can turn back the swift messenger, Radio, whose steed keeps pace with light. The gift of ail gifts is Mag- navox Radio, the Reproducer Supreme: the gift that will mean most to every member of the family, old and young. Let Magnavox bring you daily the world's news and entertainment — the greatest victory of science, the greatest opportunity of art! R-2 Magnavox Radio with 18-inch horn: this instru- ment is intended tor those who wish the utmost in amplifying power; for large audiences, dance halls, etc $85.00 R-3 Magnavox Radio with 14- inch horn: the ideal instru- ment for use in homes, of- fices, amateur stations, etc $45.00 Model C Magnavox Power Amplifier insures getting the largest possible power input for your Magnavox Radio. 2 Stage AC-2-C . $80.00 3 Stage AC-3-C . 110.00 When you purchase a Mas navox product you possess an instrument of the highest quality and service. Magnavox products can be had of good dealers everywhere. Write us for copy of new illustrated booklet. THE MAGNAVOX CO. Oakland, California N. Y. Office: 370 Seventh Ave. fAGNAVOX cRadio cJ/ie Reproducer Supreme Digitized by Google

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RADIO WOULD Answers to Readers PUBLISH a hook-up for a short-wove re- generative receiver consisting of a vario- coupl r and two variometers to a one-step of radio-frequency amplification; also a de- tector and two-stage amplifier of the audio type. I attend to use filament-control jacks. I would like to use this set for long distance. I have a V-T I and 3 V-T 2 vacuum tubes.— George Buser, Springfield, Mass. Radio-frequency cannot be employed with the variometer type of receiver. Radio-fre- quency is a different hook-up entirely and is of a different principle. In Radio World, No. 19, dated August 5, also in No. 24, dated September 9, are some very interesting dia- grams of radio- frequency amplifiers. These hook-ups for one tube, two tube, and three- tube radio- frequency amplification. • » * Give me a hook-up for a receiving set us- ing Myers tubes and vario-coupler, grid variometer, plate variometer, and detector. — W. A. Lewis, Ashtabula, Ohio. See above reply to Mr. George Buser. * * * / have just bought a crystal receiver. I would like to know if there is any chance of increasing the mileage of this set so I can hear stations of greater distance t — Carl Righter, Jr., Davenport, Iowa. You may increase the range by adding a two-stage amplifier to your crystal set. Get a vacuum-tube detector and make your set regenerative. * * » Can a tickler coil be used with a crystal set? How many plate-variable condensers should be used with a double-slide tuner self With a loose coupterf—Paul Moller, Sche- nectady, N. Y. A tickler coil cannot be used with a crystal set. The number of plates that the variable condenser should have depends on how you intend it for. A condenser having 43 plates, or one rated as having a capacity of .001 microfarads, will give quite a range of wave lengths. It is best not to use a condenser of very large capacity across the secondary of a loose-coupler when a crystal detector is used. More than .0005 mf d., is not advisable for this purpose. * # » / have a set consisting of loose-coupler and a crystal detector with variable and fixed con- densers which I intend changing into a vacuum-tube receiver. Is it better to discon- In the Good Old Winter Time THERE, /VOW. DON! THAT TAKE YOU BACK TO THAT HOT SPELL LAST AUQUST WHEN WE WAS VISITING DOWN ON THE FARM? DON'T THAT MAKE YOU FEEL WARMER- HEY f IF BROADCASTING STATIONS WOULD CO-OPERATE , MAYBE RADIO CO' t USED TO RELIEVE f L SHORTAGE (Cartoon by Harry J. StUIman) nect the loose coupler entirely and construct the set with a tickler coil; or would you ad- vise adding a variometer and variable con- denser to the loose coupler t— Harold John- son, Milwaukee, Wis. • This depends entirely on the range of wave-lengths on which you desire to work. If you want a set covering all wave lengths, the honeycomb coils or spider webs will be best. But if you want a set solely for short waves, the loose-coupler set might be better. * * * / am using a two-stage hook-up. I would like to substitute a YA-volt detector tube for a U-V 200 and still use the V-V 201 as amplifiers, also to add variometers to grid and plate circuits.— Michael Baschia, Coney Island, N.Y. It will be all right for you to use the \yi- volt tubes in your set provided you use separate battery circuits entirely for the de- tector and amplifying sections. Use the dry battery to light the tube of the detector and a separate B battery. The input to this sec- tion can be led from the place where the telephones are in the detector-circuit unit. You can add the variometers in the usual manner. * * * The radio set I purchased last month teas going along all right until something hap- pened and I didnrt get a peep out of tt. Looked it over— but cannot find any loose connections. The batteries are still **V>-J have some German condensers with a 2,000- adjustable clearance space between plat 's. — Maurice Kaplan, N. Y. I It may be possible that your con- densers are short circuited at certain points, due to metallic dust between the plates. This sometimes happens, espe- cially in condensers where the clearance is so small. Test them by joining them in series with the wire connected to the buzzer, then varying the condenser. Should the buzzer work, it will indicate that the condensers are short circuited. Clean the plates carefully or ascertain just where the shorting takes place. Your connections are all right * * # With my home-made detector „I hear most of the local stations. Sometimes I hear WGY faintly. Enclosed find my diagram and aerial. Is there anything I con add to increase the range of my sffT Possibly I may add something that will help me to tune better.— Alvin Jones, Syracuse, N. Y. Your results are very good for a 4- wire aerial, 50 feet long. Your location must be high and unobstructed. You might try the .001 mfd., variable con- denser in series with the tuning coil and then use more inductance to get the same wave length. * * * Is it possible to hookup regenerative circuit with honeycomb coils^ or D-L coils instead of variometers or varxo-couplerst Can I use two WD-U tubes in the above circuit and hook it up as one step of radio-frequency and one stage of audio-frequency T—L. C. Edgar, Detroit, Mich. It is possible to hoop up a regenerative circuit with either of the honeycomb coils or the duo-lateral coils. Using the W D-ll tubes as radio-frequency amplifiers is impossible. They will not stand up for^ radio-frequency amplification. * * * Please publish a schematic diagram for a tn'0-step audio-frequency amplifier using spider webs — primary, secondary, and tickler —one A3- plat' condenser and one 23-plate condenser.— Wendell Weiss, Cranford, N. J. This circuit was published in Radio World, No. 24, dated September 9. * * * One circuit I never found m any radio magazine is the superheterodyne. I would appreciate an article and hook-up of this set. —J. F. Swan, Seneca Falls, N. Y. An illustrated article showing the panel, front, and back view of this set with a com- plete hookup was published in Radio World, No. 28. dated October 7. Digitized by Googl

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RADIO WORLD tl Too Late! What Radio Now Offers SIX months ago any discussion of broadcasting brought up the subject of the quality of the programs which to some seemed below the average. Today the same general subject is widely dis- cussed, but the particular phase on which emphasis is placed is the interference be- tween good programs. Without a doubt the broadcasting stations are putting on features without a parallel in the worlds of art, literature, and sport, says "The Globe." New York. With the broadcasting of the Chicago opera season called a great success both by listeners-in and the management of the opera, and with the recent broadcast- ing of the New York Metropolitan stars in the opera "Aida," the American stay-at- home public is being supplied with the fin- est operatic art in this country, and, per- haps the world. Between the areas cov- ered by the two stations through which the Chicago and New York operas were broadcasted the most famous operas have been made available to two-thirds of the people of the United States and Canada. From operas to sporting events is a long jump but no feature of broadcast- ing has been followed by so many fans as the successful broadcasting of the world's series baseball games and the foot- ball contests between the big colleges. When a big corporation decides it worth while to tie up two 900-mile long distance telephone lines for three hours while play by play reports of a football game are sent over the wires to a broadcasting sta- tion, the radio fans should begin to real- ize the immense sums of money being ex- pended for their entertainment, and given to them without charge. As for entertainment and general edu* cational material, practically every pro- gram every day will be found to contain more text on subjects near to the home than any two home magazines. More- over the facts are freshly gathered and as a rule are presented in a manner that cannot be approached by cold type and lifeless illustrations. If the people of this country could be made to realize what they are missing during these fall days and nights, radio manufacturers would be forced to over- time work to fill the demand for better class receiving sets. 52 WmIu for $6.M Complete Your FiU of RADIO WORLD Copios of Radio World No. 1 If you did not get a copy of Radio World No. 1, send us $6.00 and we will send you this paper for one year, and start it with our first issue, which will be mailed yon as soon as possible after re- ceipt of order. RADIO WORLD TELEPHONE. BRYANT 4T9S PUBLISHED EVKBT WEDNESDAY (DmUd SATURDAY OF SAME UKKKi FROM PI'BLICATION OKKIOC. 149S BROADWAY. NEW YORK. N. T. BY HEN.VESSY RADIO PUBLICATIONS CORPORATION ROLAND BURKE HKNNS88T, Prasldeat ■nrt E<1lior VC B HEXNE8ST. Vlm-PTsatdrnt FRED a CLARK. litMin and Uxnutr 14 9» BROADWAY. NEW YORK. N. Y. ASSOCIATE EDITORS Robert Mscksy Fred. Chaa. Ehlert SUBSCRIPTION RATES: Fifteen cents ■ copy. $0.00 s year. IS. 00 for <li months. 11.50 for three matin. Add SI. 00 s rear extra for postals to Canada and foreign crjantrlsa. Rrrrlpt by new •ubeerlbert of the first copy of RADIO WORLD mailed to then aRer sendlnt In their order, ta automatic II 1 imwlsilrmsiil of Ibstr proportional rates. Adverttslnf ratea on request. ADVERTISING RATES: On* pace: One Urns — 1150 00. Half. Quarter. Third and Two- thirds proportlooau rales. One Inch, one time— SS.00. 10.40. Per stats Una. Oa four sonserutlrs Issues, 10% On thirteen raneerutlte Issues. 19% -11—— ti» Cmr sad preferred position rates mads known on application. Terms : 10 dan Nat. 1% 10 days. CLASSIFIED ADVERTISEMENTS! Firs cents par word. Minimum. 10 words. Dis- count of 10% on 4 oonsecuUre Issues— 15<S, an thirteen eonseeutlrs Issues. Cash with order. Entered ss sseond-slaas matter. March St. 1911. at the Post Office si New York. New York, aadar ths act of Marsh 1. ma. IMPORTANT NOTICE l While erary possible ears Is taksa to stats ssrrsoUj matters of fact and aptaloa la rasaadsal and ■snsrsl writings corsrlai the radio field, and every Una printed is rone srer with s scrupulous retard for the rsrts. ths publisher (Sseauas say rwjporjsibltlty for stalwasnts mrardlm Quest lone of patents, nrtsrttr of claims, the prapar wsrklns sat of uehnlssi problems or other mature thai may as printed la rood niu and an Informs risa furnished by ihass racpsasd to be trustworthy. This etstsatem la mads la tood faith and ta aaea oms sod sssareesno la matters srer wtash lbs publisher saaaat possibly bars ssatrsL Pignolet Ri\DIO VOLT-METER ONE INSTRUMENT MAKES ALL TESTS Writ* for booklet with aefgeatioee for tostJag eaaj adjestiew Rectto Seta. ThouaeetU sow ia sue gWm thm hate satisfaction. Pignolet Instrument Co., be. 114 Liberty Street, Now York, N. Y. Radio World, 52 Subscribe for RADIO WORLD. f&OOa year, $3.00 six months, $1J0 three raonthi. RADIO FINDS A BETTER CONDENSER IU platea spaced eloea clre It tea fin- est tunlnc qualltlsa. It la a die-cast product; the etatlonary platea arc caat solid, accurately and permanently epaced. on three upright supports, while ths movable plats* am caat on ths canter revolving spindle. Plsfs cannot loosen, which eliminates) ihorting. Ksch londenaar haa ear monsy-beek: guarantee. Prtre. SS Plate* CS.SS sasch tt Platea (S.7S serb TO JOBBER* AND DEALERS A SPLENDID PROPOSITION Bayley Condenser Co. 1*4 100 VaeeVrrrew- St.. Br—fclrm. N. T. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD IADIO WORLD Pl**u und mt RADIO WORLD for 1493 BroUwj. New Ker* City. m&t$kst for (nPrfcw»cA H—** fst* t*c\o**4 9 HJBSCRIPTION RATES: east. Copy 4 J» rhte* Montbo LS we Moetbs JJO has Year (» Usees) fcSD \dd tl OS • Veer tor Pe • art < ana Digitized by Google

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Let Radio World Test Your Goods MANUFACTURERS, send a sample of yew goods to oar Technical Editor, Fred Charles Ehlert, 9006 Pleasant Street, Queens, Long Island, New York. It will be carefully tested. If your goods satisfy our experts, RADIO WORLD'S endorsement will be published in our merchandise department without charge or obligation of any kind on your part. When the radio pur- chaser sees a published test in RADIO WORLD with the seal accompanying this editorial attached, he will know that the prod- uct stands for perfection and has the guarantee of RADIO WORLD. RADIO WORLD is rendering a serrice through its testing department that is prompt, accurate and produces result*. All goods will be returned to manufacturers, after testing, pro- vided stamps are sent for that purpose. Heard at Radio Counter A Conversation Between Customer and Radio Clerk (Part VI) IN building a radio-frequency amplifier, should the panel be shielded for body-capacity ef- fects?" "In either radio-frequency or audio-frequency amplification, body-capacity effect* will be elim- inated if the panel It shielded." Then you really believe that in an unsheathed receiver using radio frequency, there is a loss due to the set being Improperly constructed 7" "Absolutely. In every case, shield your panel." "Can I connect my output from the three- stage radio-frequency amplifier to the input of the audio two-stage amplifier with a detector 7" "Yes. This can be done very nicely and easily with a little patience. Watch carefully each con- nection you make, taking car* of the proper plate- voltages. Another thing: don't forget to us* all amplifying vacuum-tubes outside the de- tector. In this case, of course, we have to use the soft tube, better known to the layman as the detector tube. This, then, will give five amplifying tube* and one detector tub*." "Will my outside antenna work best with such a set; or must I employ a loop aerial?'' "Employ the loop aerial by all means and avoid using the outdoor aerial. The reason for the loop aerial is elimination of interference from stations, making the loop a practical com- pass-loop and cutting down static as well as interference." (To Be Continued) The Coming Events rs of RADIO WORLD win g: • item* of raS shews and eaaoetMena. Keep us Boated by mailing fall tmiermatiea. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co*. Chicago, January 13 to 20, inclusive, 1923, George A. King, director of publicity, 417 South Dearborn Street, Chicago, ID. PERMANENT RADIO PAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION, Grand Cen- tral Palace, New York City, December » to 31. Colwell ft Korbell, Fisk Building. New York City, director* of publicity. SOUTHEASTERN RADIO EXPOSITION, Andi- torium Armory, Atlanta, Georgia, December 4 te a Inclusive. Co-eperativ* Radio Sales Aasa., M Paachtre* St. SECOND DISTRICT RADIO CONVENTION. Hotel Pennsylvania, New York City, March 1, a, and 3, 1923. A Valuable Book THE third edition of the "Amateur Radio Call Book" has been issued by the publishers, Radio Directory & Pub- lishing Company, 42 Vesey Street, New York City. It contains a complete list of all amateur, special amateur, and tele- phone broadcasting stations of the United States and Canada, also a large map in two colors showing the location of every broadcasting station. In addition, it con- tains valuable information on the con- struction and operation of a honeycomb- coil set, detector and two-stage amplifier. The book is divided into districts in the United States and Canada. The editor and compiler is Walter B. Spiegel, mem- ber of A. R. R. L., and H. R. C. Every fan and amateur, particularly the DX night owls, will find this a valuable book. It contains just the information such radioists are constantly seeking. Price $1, complete. New Firms and Corpora- tions (The firm* and corporation! mentioned m these columns can be retched by eating with the attorneys, whose addresses are given whenever possible.) A- 5Sj!2£.het.' ?ronx< Phonographs and radio sets, $40,000; A. Schochet, A. Mintz, D. Lerman. (Attorney. P. Lerman, 110 West 42d St., New York, N. Y.) CAPITAL INCREASE The Orange and Rockland Electric Co. has in- creased its capital from $1,000,000 to $6,000,000. Selling Radio to Farmers T T is said that the farmers did a great * deal toward making Henry Ford. They purchased automobiles because the automobile was a convenience that brought the city to their back door, says "The Mail," New York. Who in radio is going to sell the farm- er radio receivers? It is high time that such a campaign started. The rural ter- ritory is a potential one. Some business genius is going to hit upon the right plan for selling the farmers, and when he does he is going to make a fortune in a very short time. Radio can be made indispensable to the farmer. This was proven by a re- cent case in Pennsylvania. A peculiar form of worm found its way into the corn fields. It was bringing about great de- struction in certain localities. Experts of the Department of Agriculture got on the job and used the broadcasting sta- tions of that State to tell the farmers how to effectively eliminate this pest. Great speed was essential; a delay of .a day or two would wreck a large crop. The farmers who had receiving sets were out in their fields the next morning, ap- plying the remedy that had been broad- cast. Broadcasting can be made so impor- tant to the farmer that the business angle of it should be handled by the vari- ous States working through the Depart- ment of Agriculture. A State owned and operated broadcasting station used to dis- seminate not only the information regard- ing market conditions, but practical talks on scientific farming would be a very good investment, costing only a small amount and bringing a large return. If a farmer loses a crop it may cost him anywhere from seven to eight thousand dollars. The State loses a certain amount of income, not only through tax but through general financial welfare. RADIO GOODS AS GIFTS Be sure to be represented in "Holiday Radio Gifts Number," out December 9, Copy for this issue accepted up to Novem- ber 30, Radio World, 149 Broadway, New York. FANS. AMATEURS, DEALERS, BROADCASTERS, MANUFACTURERS, AND THE GENERAL PUBLIC Are Looking Forward to NATIONAL RADIO WEEK DECEMBER 23 TO 30, INCLUSIVE All Interested in Radio Should Help to Make This Event a Smashing Success. If ran want to know mora about it addrsssi NATIONAL RADIO WEEK EXECUTIVE COMMITTEE J. ANDREW WHITE, Chairman 326 BROADWAY NEW YORK Digitized by Google

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RADIO WORLD 23 Latest Radio Patents To Receive a Plurality of Signals No. MSMM. Patented, November 7, 1(22. Pat- en tea: Edward W. Kellogg and Chester W. Rice. Schenectady, N. Y. \/f ESSRS. KELLOGG and Rice have been granted letters patent on a device to provide a method of and means for utilizing an antenna for the simulr taneous reception of a plurality of sig- nals of different wave lengths. With a long receiving-antenna extending in the general direction of transmission of the signaling waves to be received, signaling currents produced in the antenna by waves coming from any particular trans- mitting station will be strongest atvthe end of the antenna farthest from the transmitting station, while currents pro- duced by waves coming from the opposite direction will be a minimum at that point. The antenna is preferably aperiodic, so that the strength of the signaling currents produced therein is substantially inde- pendent of the wave length. In carrying out their invention, Messrs. Kellogg and Rice utilize an antenna of this type and impress from the antenna upon the input circuits of a plurality^ of electron-discharge amplifiers potentials produced in the antenna at a selected point. In order to improve the recep- FloJ flo2 lj 5 . Schematic design of the KeUogg-Rlce receiver. tion, they also provide means for im- pressing on each of these input circuits a current selected from another point in the antenna which will be of the proper intensity and phase to neutralize in each receiving set, disturbing currents pro- duced therein either by interference from undesired waves or by strays. Each of the output circuits of the amplifiers em- ploys a resonant circuit which is tuned to the frequency of one of the desired signaling waves, and these resonant cir- cuits are associated with receiving sets. Low-Priced Condenser No. 1, 4*3,2 44. Patented, October 24, UK. Patentee! John Parkin, Jr., San Rafael, California. f")WING to the number of persons at pres- ent experimenting in radio signaling, there is a great demand for a variable con* denser of simple construction and capable of being made and sold at a low price. Mr. Vertical section and Parkin's invention is to provide a variable condenser to supply this demand, and in which the elements are reduced to the least possible number arid are of the greatest pos- sible simplicity. The Truth Will Bear Repeating CHAS. FRESHMAN COMPANY 97 Beekman Street New York City November 7th, 1122. Radio World, 14*3 Broadway, New York, N. Y. Gentlemen t— We wish to thank yon for your successful effort in getting sddltional advertising copy on our Variable Grid Leak and Micon Condenser la your publi- cation to appear in the issue of Saturday, November 11th, 1*22. The reason that we sent you -the copy at such a late dale was that it has been our policy to advertise only one of our various products in each magazine, and we had an advertisement running on our Noiseless Tooted Micon Condenser for your coming The results that we obtained from our first advertisement of the Variable Grid Leak and Micon Condenser combined were so great that we did not want to miss the opportunity of having it re-appear In the It might Interest yon to know that out- side of the general publicity that our Variable Grid Leak and Micon Condenser combined received from the Arst adver- tisement m your publication that we have received hundreds of direct orders from Individuals and payments enclosed mem- tionlng the fact that they saw the adver- tisement In RADIO WORLD. These in- quiries rams frees all sections of the country. We wish to congratulate you on the 1 distribution of ] Yours very truly, CHAS. FRESHMAN COMPANY, INC. (Signed) Myron Coldsefl Vice- President In Charge of Sales MGJJ ' Out Next Week! On Sale Wednesday, December 6 — Dated December 9 ft Remember "This Is a Radio Christmas and that millions of dollars will be spent during the holiday time for radio gifts. Be sure to get your share of this business by advertising in the issue of RADIO WORLD of December 9, which will be RADIO WORLD'S CHRISTMAS NUMBER Thru this medium you can reach thousands of readers, who are not only interested in radio themselves, and want new equipment, but who also will give presents to others whom they wish to make radio fans. ADVERTISING RATES: Regular advertising rates In force for RADIO WORLD'S HOLIDAY RADIO GIFT (CHRISTMAS) NUMBER, as follows: $150 a page, $5 an Inch. Discount, 10% four times, 15% thirteen Utmee. Last form cloaca November 30, A. M. Take advantage not only of RADIO WORLD'S circulation, but also its cash-thru-the-mail pulling power. Be represented in RADIO WORLD'S Holiday Radio Gift Number, and reach the many thousands who actually want your goods and are ready and willing to pay for them. Preferred Positions Must Be Booked Immediately . Copy for mn-of-paper position will be received up to November 30, A. M. RADIO WORLD, 1493 Broadway, New York Digitized by Google

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24 RADIO WORLD PATENT Your Radio Ideal. Call or Write FREE ADVICEI rj?U F IF TH AV L ■--'*< J~ ' I ^ INSU-LITE ^ l/i" —31 per eq. ta. A t/16"— .014 par go. Is, N 1/4" —M nor at. la. E DEALERS: Writ! for Mto—TM. £ General Merchandise Co. S 14* Market BtrMt. Newark, M. J. $4 CRYSTAL SET "THE LITTLE WONDER" fug UNMOUNTED Wonder in an and a wonder in per- formance. Cannot be equalled for the price. Catches distinctly everything broad car ted within 30 mllei Send for FREE catalog, dcocribiag oar "Little Wonder" net and (Urine ndlo »up- CUAKANTEED. TESTED CKYSTALS 20c Helleway Electric m Third Avenue New York CKf The NUtieet Short War* Tuner on the Market Only WjN * PP on 1 lb. Send for pamphlet. L. W. GOODMAN DREXEL HILL, PA. Malar —, HaJMeju N. 8.. writer: DegfMtd. KtMlvta srlMamtagY ilrarly ta mm teka trrt tlae I triad tat 800 D MAN. WtaM M* tend traekle and ■taty by buylti Matin aft- m # I BATTERI" FOR DEPENDAl GUARANT] ASK YOUR DEAl-E NOVO MANLFACTl 424-438 W.-33'J' SI 531 SO. DEARBORN ST, CHICAGO. issues for $6.00. Sub. De- iio World, 1493 Broadway, Erecting SPC, Brazil On the Summit of Mt. CorcOTado, It la the Hi cheat in the World By Patrick Nichols CENTERING the beautiful city of Rio de Janeiro the most impressive sight is the exquisite mountainous background of the city, and particularly Corcovado, an almost perpendicular mountain, with its summit over 2,000 feet above sea level. "Why erect radio masts when such a mountain is so near by?" queried the Westinghouse engineers who journeyed there to erect broadcasting station SPC. "Can we get the location?" This question was answered in the af- firmative by F. A. Huntress, General Manager of the Tramway Light & Power Company, who own the cog-wheel rail- way that climbs Corcavado. He also stated, "We can supply 120-volt or 220- vblt, 50 cycles alternating current on the mountain top for the radio outfit." The party set out to explore the moun- tain crest. The first 2,000 feet of ascent, or five mile ride from Rio de Janeiro, was made in 30 minutes, and the final climb of 125 feet by following the foot path to the circular observation tower on the top. A quick survey of the available space on the crest disclosed a narrow path about 120 feet long, leading to a con- crete parapet on the edge of the precipice. The crest of Corcovado had always been used as an observation point, but the radio-telephone engineers saw more than mere scenery— they had a view of the prospective invisible radio audience. Two 125-foot masts were erected on the verge of the precipice on which are stretched a 153-foot six- wire antenna be- tween two 26-foot spreaders. _ The coun- terpoise consists of two sections of five wires each, mounted on two 26-foot spreaders which are balanced on the ends of the 70-foot horizontal pole bolted fast to the mast on the summit. The counter- poise wires are stretched clear of the mountain sides, down about 100 feet to the tops of two poles located near the terminal building of the railway where the wires converging symmetrically form a 10-wire cage which leads into the radio telephone operating room. The hum of' the 220-volt alternating-current motor was eliminated by a filter system made up of microfoid condensers and large choke coils. A single-wire antenna was strung from the mountain top to the operating room about 125 feet below, for receiving mes- sages. A speech amplifier is located in the operating room. The call letters, SPC, were assigned. SPC has a unique position in the radio- telephony broadcasting field. At various timfs the station and antennae are in or above the clouds. Rio de Janeiro is practically on the boundary line between the Temperate and Torrid Zones. The climate is varied by the mountain range Serra do Mar which runs along the coast. The dry season will soon change to the warm and wet season and its subsequent tropical storms. Precautions are being taken to prevent electrical interference. The observances and records of SPC will, therefore, assist in studying the pe- culiarities of the air as far as radio-tele- phony is concerned. The experiences of this station in penetrating the Equator and the Torrid Zone, when corelated with the data being compiled by other stations and close students of the new science, will no doubt result in listing peculiarities of the atmosphere unknown to science to-day. "HOLIDAY RADIO GIFTS NUMBER" of Radio World will be issued December 9. Last copy will be accepted on this number up to November 30. Radio World, 1493 Broadway, New York. Did you eee oar ad fat RADIO WORLD of Nov. 18, Page 27T Watch for fata re announcement!. RADIO EQUIPMENT MFG. CO Deal "«," ISM lltHI AVE. NCW VOKK. N. V. MICR0STAT Vernier Rheostat The Khaootat with a M At $1.40 MICROSTAT COMPANY WnXIAMSPORT, PA. Do Your Buying At PERMANENT RADIO FAIR Hotel Imperial 32nd Street and Broadway New York City Buyers — Dealers — Radio De- partment Managers, Demon- strations of Any of the Pro- ducts of the Exhibitors. Only Products of Representative Manufacturers Are on Display. Nearly 100 Manufacturers Now Exhibiting FRS ALL MOLDED UNIVERSAL COMBINATIONS 0 Unite in S F. R. B. Melded Variometer* F. B. S. Molded Varteceaplere. . . F. B. 8. Melded Bank Windings. Bank Winding* are Interchangeable for direct mounting on either Variometer or Varlocoupler. Unlvereal — Accurate — Interchangeable Set lncludea two Federal TTanaformera, Condenter. two-molded variometer*, molded varlocoupler, three V. T. eooke** filament rheoetata, dials. Read 'mi binding poate, awltch point*; In attrac- tive cabinet and drilled panel: complete, ready to hook up. A 1125 Radio for $40 F. R. S. Radio Corporation 4M-B Kaat Fort St. Detroit, MJeh. Digitized by Goog IC

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25 DICTOGRAPH Radio HEADSET WasWs NOW A sweeping cut of $4.00 in the price of the Dictograph Itadio Headset! The kernel endorsement of radio enthusiast* has made possible this sensational reduction. To meet the demand, production has been planned on a new, gigantic scale. Great manufacturing economies establish the new price — only $8.00. A wonderful bargain! And above all. a wonderful headsct-thc world's standard of supreme quality for super-sensitive and accurate sound-transmission. x. „orn„ mlfliitv the same guarantee, the same supreme Dictograph headset that has aZ^ lZZ^X Zry^a but the price. Type R-l, MOO ohms, for .11 types of receiving sets. THE STANDARD OF THE WORLD List Price The Perfect Loud Speaker for the Home Public aem»nd hu mad* poartbl. the Dictograph Loud Bp«»ker at th. ilow pHc. of only 110.00. complete with t ft. flexible cord. A hendMme Inatramont that renroducee every eound In cryetal-clear. natural tone., full volume, and free from m.tort"on or noT« Art for demon.tr.llon .t reliable radio dealer* Oot world- famoua DICTOGRAPH quality and itlll a«ve money. Dealer.: Order throu.li your Jobber or writ* direct for name, of ..thorUed distributor*. DICTOGRAPH PRODUCTS CORPORATION M0 Wert 4*d Street (Branch** In all principal cltle*) New T*ck. 1*. Note: runs are new way far the production of the new 4,000 ohm* Decteorrmpb SrrKK-TONX Headart. the meet perfect rmdlo head eat r*r the the meet ex art Ins nqaureauaU. A ar* of aaper-oeaattiT*- Llet price, tit.—. Vtrlonittn with dial, fUt VvioeonpWs with dial, $IM Tot Paid Monty Back if not Batitfactory OS LAND, INC 122 FIFTH AV. NEW YOU PHANTOM-CIRCUIT at ataU* awe.iro. We ieaah«eaUy hear «aa*ans a* IH teat fteai ham. Th* eltapUeltj at thla sal "An earprteo m N* redte hmeeay. Oiamjili t*i tie*, with peace *f etretat east prepaid te •«*. TOO) RADIO SHOP. Urn W-TM. SPECIAL OFFER Far a Uaaitad RA-M....*M Creke C*-* -. DA-1 Grab* RORK. Priea* F.O.". Red Peak. M. J. A. V. GREGORY N. J. INCREASE YOUR CRYSTAL RANGE BV IBINO A TT ILTEA-IIXHTITI CONTACT IN TOI'B CRYSTAL DETECTOR I. II ail*** la • nine. t. Ilia li am «Multh* reeelt*. t. la eHaert lamnlMa to tar eat. Proa) twerty-tn aatte ejrear. -PT- CRYSTAL CONTACT CO. In MM BOSTON ». MAW. Ihmm»M Ar D—hn tar ge/iaiWO RADIO STORES CORP. VARIABLE CONDENSERS— PLUGS— RESISTANCE VNTT8. ETC. If yaw deater eeeea't evry. addraa* Doet 0. lit W**t Mta Street. Hew Vera Radio Rates from Italy OFFICIAL reports of new lines of radio communication between Italy and the United States, following the re- cent suspension of direct radio communi- cation and pending the completion of a new high-power station at Rome, have been made to Washington by Commer- cial Attache MacLean. at Rome. Radio traffic from Italy for the West- ern Hemisphere is now being handled by the high-power stations of Germany, France, and England, according to state- ments of the Ministry of Posts and Tele- graphs at Rome. Full-rate and deferred messages, and press telegrams may be sent by Nauen Transradio and Radio- France, and full-rate and deferred mes- sages by London Marconi. Messages sent by Nauen are transmit- ted by radio from Rome and relayed at Nauen. Traffic handled by France or England is sent by land wires from Italy and thence by radio. Messages by France or Germany will carry a rate of twenty centimes, gold, less than the cable rate, in the case of full-rate telegrams. By London, the same messages would be ten centimes, gold, less than the cable rate. Deferred dispatches will be charged half the above rates. Press reports may be sent by France or Germany at the same rate as deferred messages, but will not be handled by London. Two Danish Radio Clubs TWO radio clubs, organized and sup- ported by some of the most promi- nent figures in the Danish field of com- munications, have recently been formed to promote interest in radiotelcgraphy and radiotclephony throughout Denmark. The aim of these clubs is to spread knowl- edge and create interest in wireless com- munication through lectures, demonstra- tions, and other means. RADIO MAILING LISTS til* Betall Badle Dealer*, United Hiatea Per «■■ 11X4 hullo Majiufeetureri P" 1330 Re-Uo Sui'i-lT Jobber, Per UaU 151 IU.Bo manutaeturere of ton- {•let* ecu P»» "«•. !«• Ha llo Slatlone per oat. 14000 Jtaillo Amatrura an. I Man* afire of Radio Stallone . per If. Neatly tYi-.-a-rtu-ei anil rre-b to em<l ft roealpt of rvmlltenre emerlai the ami -int. TRADE CIKCt I.AR ADDRKfMSO IH W. AOAIol ITIHIT CMICA00, IT. SO 10 00 11.00 4 00 4.00 I 50 CO. ILL. eou*u Htao b<m!i A REAL ABSOLirniY FREE R I Mil year aaake aau aeai.i and •« •ill tail yea HOW yen tea tret tale RADIO BIT ABSOLUTELY FREE. KADIO ItET main la yea aoee pleta. antk alalia alio. L errata] c er. AND DOUBLE N E A 0 PHONES Ne balteiiee required; aa a. I enea Write Ti-aa, far Free •I ad la Plea NOME SUPPLY CO 1 1* Naaaae IL.Oeet. 20- Me* Vera City « \ — CmmMty, D—ion * WormmmnaMp ♦ Notarial = RKU ABILITY SaaaleteUae lamp eockat .0- lacb cb'pe to bat- tery— turo om cur- rent and yon *-*•* your ova cbax.- irig plant. A compact portable Rethare-in. writ ***-* writ] folly chars* a 100 AH battery OYrmifhl tor Sc. to 10c At voter aValer* or a-Hfe Kmc Electric Mfg. Cos Inc. tm Ai 1*111 RaJFaa*, N. V.

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96 RADIO WORLD DELICATE SOLDERING Both the manufacturers' and amateurs' problem on all fine work is readily solved by the instrument constructed for this particular purpose. THE POST SOLDERING IRON Platinum Heating Unit — Interchangeable Tip — Universal Current One Half Actual SUe $6.00 From Your Dealer or Write Awarded Certificate of Excellency, N. Y. Evening Mail Radio Institute POST ELECTRIC COMPANY, (Div. 509) 30 E 42nd St, New York A Big Christmas Surprise Send for our bulletin A21 and see what SANTA has to offer you, in RADIO SETS COMPLETE. Also in parts, "A" and "B" Batteries. We handle the best money can buy in Radio, and we are giving you a won- derful Christmas treat so all can en- joy Radio this year. These offers last til] December 25th. Drop us a card and receive this Sur- prise. Radio Supply & Service Offices: 119 West Chicago Street 8TCRGIS, MICHIGAN SUNRAID Rheostats POST-PAID $1.25 None Better Few So Good Filament cannot loosen and fall out. Pressure is even against the inside wall, therefore eontact is always tight and true. Unexposed filament means protec- tion from shorting. Spring and Ball contact on finger. Efficient on all tests SCHEMAN & CARLIN 534-8th Ave. New York City Broadcasting in Brazil Centennial Celebration Stirred Up Interest and Promising Market for Receiving Sets Is Predicted ONSUL General Alphonse Gaulin, Rio VJ de Janeiro, reports to the Department of Commerce that preliminary steps have been taken for the introducing of radio broadcasting in Brazil, that indications point to a promising future market for receiving apparatus. Until recently radio broadcasting was practically unknown, but the Centennial Celebration being held at Rio de Janeiro has served to stimulate interest in radio and various concerns in Brazil have been active in taking it up. The Rio de Janeiro Light and Power Company has recently finished a broadcast- ing station on the heights of Corcovada, using a wave length of 483. Music from the Municipal Theatre is sent to Corcovada summit by telephone and after amplification is sent out by radio. A studio near the sum- mit also furnishes concerts and other en- tertainments which are heard locally. Ad- ditional broadcasting stations are now lo- cated at Monroe Palace (Congressional Building) and at the offices of the Marconi Wireless Telegraph Company. A number of receiving sets have been installed in the exposition buildings. Imports of wireless apparatus have been received both from the United States and Germany for sale during the exposition. The requirements of the Brazilian law, how- ever, make it obligatory for any person wishing to install a receiving set to secure a special permit from the Department of Transportation and Public Works. Only such receiving sets as have been approved may be sold by importers especially licensed to make such sales. The restriction and that limiting the sale to persons who have re- ceived a license to install and use wireless apparatus have hindered the exploitation of this important product. It is hoped, how- ever, that by the beginning of the year a more definite policy will be established by the Brazilian Government and the markets for radio apparatus thrown open to im- porters. Subscribe for RADIO WORLD. $6.00 m ar, $3.00 six months, $1.50 three months. A Broadcasting Problem Should Manufacturers Contribute to Sta- tions Sending Out Programs? Asks Bel Canto Corporation IpoiTOR, Radio World :— Broadcasting has been under discussion for some time and much has been said pro and con; but I have something to say which I think is of paramount importance. The Radio Corporation of America was the pioneer in broadcasting radio concerts and has not only kept up the fine quality of these concerts but has improved on them from time to time, giving radio fans the best quality of talent procurable. Without this broadcasting, there would be practically no market for radio parts, and it is my opinion that each and every manufacturer of radio parts — whether it be a loud-speaker, a complete set, a hun- dred feet of antenna wire, or any of the other numerous parts that go into the making of a complete set — should be will- ing to contribute a certain portion of his net profits towards the maintenance of such a station. Each and every manufacturer of radio parts is indebted to the broadcasting sta- tions. Without them the manufacturer might just as well put the key in the door and hang up a sign, "TO LET." Why should a corporation, such as the Radio Corporation of America, spending millions of dollars to make radio a per- manent, sound and healthy institution, which in time is destined to become one of the greatest industries of the world; or, in fact, any other organization main- taining broadcasting stations throughout the United States, bear the entire expense of maintaining these stations? A certain percentage of the net profits of all the manufacturers, in my opinion, should be set aside to be paid over to the proper organizations conducting broadcasting stations throughout the United States, and that all unnecessary broadcasting of concerts, lectures, etc., should be abandoned. There is no neces- sity of having numerous broadcasting sta- tions in one vicinity, for it only causes interference, which the average radio fan cannot tune out. Proper broadcasting is the only thing that can make radio a real success; and I say again that each and every manu- facturer who is now conducting a profit- able business owes every cent of profit he is making to broadcasting. We are willing, ourselves, to set aside a certain portion of our profits for the purpose above mentioned. We feel that all other manufacturers will be in accord when they give it due consideration. — Duryea Benscl, secretary-treasurer, Bel-Canto Corporation, 417 East 34th Street, New York, N. Y. STANDARD HEADSET 1,500 OHM SttLMSCfS J7.r" $5.75 Dealers and Jobber* write. Standard Electric Sales Co. M« Broad Street Newark, N. 1. THE ATLANTIC &. DACIFIC HCME OF I ERFECTION » » RADIO COMPANY--***— BEST by TEST ™« "Acme of Perfection" radiophone set dm bocn proven better than the best I We have received Innumerable compliments and hare be- come convinced that there la none better. This jet has an exceptionally long distance range: has ^L'm^f 01 °" °* market: eriml£ »" «1°" : reproduces the human voice and other sounds perfectly; and Is operated atmnl* mS ijLui *™""J- We can show customer's testi- monials on the wonderful performance of this let. All our sets are sold on Money-Back Guarantee! Write tor "Acme of Perfection" Folder on Seta from US Up We Carry Everything in Supplies ATLANTIC & PACIFIC RADIO COMPANY Show Rooms, 131 W. 37th St, N. Y.

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RADIO WORLD 27 Broadcast Bill's Radiolays By William E. Douglass THERE ain't no use in talkin', I've had troubles of my own, an' lately they've been pilin' in, they never come alone. First off I lost my chickens, dern near all died with the pip, an' then my' dog keeled over without lettin' out a yip. The bay mare's got a collar-sore from plowin' here this fall; the other one is spavin'd — luck's deserted me, that's all. On Sunday I got all dolled up to take tune comes my way, she does the thing up brown, but all the same it takes a heap to keep my spirits down. I've noticed too, most every cloud that dims our path so bright, has got a silver lining an' most things work out all right. Just last week, for example, Min got out my winter suit, an' found that it was stained a bit with plums and other fruit. She worked with it for quite a while an' got it good an' clean, I guess she must have used about two quarts of gasoline. Then in the kitchen by the stove, she hung it up to dry— the "Hook and Ladder" boys will tell you now I'm one suit shy. Like- wise the house where I was born ain't what it used to be, we're shy about eight rooms or so, as far as I can see. We saved 'bout all the furniture an' grand- ma's feather bed, the only thing she thought of, though, was that there fancy spread that won first prize four years ago down at the Country Fair, an' after she had got it out she didn't seem to care a rap about the other stuff. But, like I said before, though trials and tribulations congregate about my door, there's bound to be a rosy side. My trouble's I'll for- get, because I rescued first of all my good ol' wireless set. —Copyright, 1922, Westing-house Electric & Manu- facturing Company. Min in to church, an' when I cranked our Lizzy, she just up an' gives a lurch, an' knocks me down, blacks both my eyes an' tears my Sunday pants. Some- times a flivver's pesVy if you give 'em half a chance. I called old Lizzy some hard names, not knowin' why or which; to even up, on our way in, she runs off in the ditch. We got to church in time to hear our friend the parson say, " give thanks for the blessings Providence may send your way." When old misfor- Radio Don'ts T\ ONT transmit without a foftnunt Don't be careless about your set. Don't let the aerial wires touch roofs, buildings, or trees. , Don't purchase cheap apparatus and expect long- dietanca results. Don't place too many wires in your aerial. Don't forgot that Just as much tuning is required In the secondary as in the primary. Don't blame the set on poor reception. Some- times It is improper tuning due to your own fault. Don't light the filaments to exceptional bril- liancy and expect loud signals. Don't monkey with the works of your set If something goes wrong. Take it to an ex- pert radio-dealer. Don't keep on changing connections if signals have been heard at their best. Leave well enough alone. RADIO UP TO A STANDARD » 135.00 fires* C. R. «— ISO te 3000 132.00 Weetlneneuee R. C. Psrases R. A. 10 1 12.00 De Fernet M. R. 6 23.00 Federal J. Set — cenplete (keen 35.00 Tueke Deteetsr Set BUT DOWN TO A PRICE etere $88.00 S7.00 00.00 S4.00 with V. 200 U. V. 201 Nety V. T. I PHONES Baldwin Tym C Baldwin, elagle Hilar Cabet Murseek 3000 ehm Msrdeek 3000 ekm. single. Mardcek 2000 ekai Herat* 2000 ekea. single Federal 2200 eka Federal 3000 eka Western Electric Fnatk Brasett 4000 eka III. 50 0.25 5.30 4.50 2.00 3.50 1.50 0.00 4.05 7.50 7.50 7.75 VARIABLE CONDENSERS 23-Ptate Vernier $5.25 43-PUte Veraler 5.75 .001 Balanced De Foretf. 4.75 23.Plete. neelm* en*». . . . 1.25 23-Plate, slain 1. 00 VARI0COUPLERS Balayle »»4.50 All Ranee 6.00 All Wave 7.50 Atereter- Kent 0.40 f«ee 4.75 Tana 3.50 Prleee Goad <er December, 12.50 25.00 TUBES $3.00 I Nevy V. T. 2... 4.00 W. 0. II 5.00 I 0. V. 202 8T0RAQE A B BATTERIES 00-Heur Exlde $17.00 1 20- Hour Wectlnghouee. . . 10.00 wcetlngneute Stnie B . . 5.75 22% V. France Variable.. 1.75 45 V. France Variable 3.50 22V. Burgee Var 2.25 SO-Heur Wirtlnihouet.... 14.00 BATTERY CHARGERS Hemkeroera $13.50 Wertinokeuse 14.40 Weetlngheuae (lane) 22.00 RHE08TATS Radle Cere $2.40 Reakler 00 Star 60 Cutler Hnaemer 80 Murdeck 75 Paragcn 1.20 Klocncr 55 POTENTIOMETERS Radle Cere $1.50 Paragon 1.50 Graphite 1.20 Amuo 1.05 LOUD 8PEAKERS Maanavm $32.50 Federal Hern g.00 $40.00 Turney Deterter Set $20.00 30.00 De Fereet Detseter Set. em elala with tub** ead battery M-JJ De Fereet 2-Staee Amplifier 'JJ SJ gf»*«" Heetrle 2.»taoe Amplifier. 40.00 Clapp Eacthaa Tuner aed Detacter 25.00 IS.00 90.00 29.00 King Here Dictagraph Autevelx Weetern Electric .. Baldwin Clarephcne VARIOMETERS Paths .. $7.00 . . . 4.0s . . 0.00 .. S.S0 .. 15.75 .. 17.50 ..112.50 .. IS.25 $3.50 5.25 3.09 0.40 Baldwle Atwater-Keat , . TRANSFORMERS i 7";ii:::::::: n*4 Acme' '.'.'.'.!!!!! A teeter- Kent Federal Parages Meyere Cell De Fereet Marie Thorite run RADIO FREQUENCY „ TRANSFORMERS U. V. 1710 $7.00 u. v. i7i4 :::: i.lo Radle Service 4.75 Beldwln 2 25 Acme 4.00 5.60 3.75 4.50 5.25 4.00 3.00 3.00 3.00 2.50 1922. Orders Must Include Poetage and Money Order.' ' S77 MYRTLE AVE. Phone Prospect 2952-8168 REPRESENTATIVES WANTED! — - , : , J a -"."."l ravKri — ~T-'. "d kijg buainese concern thrnout the country. gairticwUrn. RADIO WOULD, 1493 Broadway, New York C3tyT RADIO BOOKS FOR XMAS The Most Acceptable Gift Prices to Suit All "Design and Data For Radio Transmitters and Receivers"— Paper cover 55c "Radio Hook-ups"— Same type cover as above. Never sold less than 75c. Sale price 65c "Radio For Everybody" — The famous book. Heavy cloth bound. Sale price fl.00 "Radio Phone Receivers" — A practical book for everybody. Cloth bound. Bale price. .. .fl.00 "Radio Experimenter's Handbook" — A book to answer tbe practical pnoblema of beginners of Radio Experimental Work. Heavy cloth bound. Sale price five "Practical Wireless Telegraphy" — Heavy cloth bound. Sale price •1.80 "How to Conduct a Radio Club" — Plenty of de- sired Information. Sale price 50c "Practical Wireless Stations" — This tells you how and why. Sale price 55c "A Complete Wireless Course" — Heavy cloth bound. Sale price ooe "How to Make Wireless Receiving Apparatus"— Paper cover. Sale price 25c "Wlrelesa Construction and Installation For Beginners" — Paper cover. Sale price 25c "Experimental Wlrelese Construction" — Paper cover. Sale price t6c "Complete Radio Receiver"— How to make your own. Paper cover. Sale price 20c . "Armstrong's Super-Regenerative Circuit"— A book complete In Its tine. Sale price 70e DIAGRAMS Detector and Two Stage— Complete with In- structions. Sale price S5e Short-Wave Regenerative Receiver— Wonderful opportunities with this circuit. Sale price tfle Armstrong Super-Regenerative— With full in- structions. Sale price S5r BLUE PRINTS Armstrong Super-Regenerative Hook-up — With list of material needed. Sale price 25c We have any and all the PARTS to make the beat apparatus at a very low price, and Invite your Inquiries and trade. Tbe books listed aa paper covered or the diagrams win be given FREE with purchasea of parts for any set. We have in stock the new Spider Web In- dactanre for Bhelnharts Tuner — A wonderful new Idea, sure to prove satisfactory, full In- structions $2.40 Tubular Glass Grid Leak Resistances at the special low price of S5c; elsewhere 76c. / DUO LATERAL COILS DL-25, 35 and 60.. 85c 1 DL-1250 DL-75, 100 at 200.. 60c DL-1500 DL-260 «5c . .$1.86 ..$L«S Jones Licensed Regenerative Receiver $58.00 Detector and two etage amplification In- cluded with above outfit. Bulbs and batteries f?irS;-.Thl* ,et a wave length range of 150-2500 metres. _ All sales prices in November issues of Radio World are good until Xmas. Postage must be included with order. Checks must mclude 10c exchange and please have them certified. All goods are shipped P. P. in- sured. RADIO DISTRIBUTING & AUTO SUPPLY COMPANY 64 West 66th Street, New York City Phone Columbus 8584 ■( - Digitized ^r^VAvenueT iway

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28 RADIO WORLD The HOMCHARGER AUTO or RADIO BATTERY lor a Nickel. Pries. tlt.lt Seed tar FREE Bsllrtls DEALERS— WklTf NOWI TIM Automatic Electrical w Devices Co. •P West Third St., CI*., 0. TOBACCO HABIT BANISHED QUICK, SURE, LASTING RESULTS Tobacco Redeemer banishes the habit com- pletely, almost before you know it. An absolutely •clentific, thoroughly reliable treatment. No matter how long the habit, or in what form used, you will have no craving for tobacco after you take this pleasant, inexpensive treatment. This we positively guarantee. Your money returned without argument or question if not satisfied. Write for free explanatory booklet and proof of what Tobacco Redeemer has done for men addicted to the tobacco habit. Send post card or letter today . tortll PtormetJ U*L 171 , It Louis. Mo. Detectors Save*350 Those Broken and Burned-Out Vacuum Tubes Can Be Repaired Harvard Radio Laboratories US M«> Street BOSTON, MASS. Tubes returned P.P.. C.O.D. GITHENS TRUTONE RADIO HORN— LOUD SPEAKER First one to sail on ton day trial Money back Guarantee Retail Price $21.09 Include* Loud Speaker Trutone has been pronounced the beet oo the market by experts. It hu e clear, true tana Every radio fan should try Trutone and compare It with others. If TOU don't And Trutone the best, your money will be refunded. It Is sold on a ten-day trial money-back guarantee, ir not carried by your dealer write ua. i Distributors and Dealers, write 1 AUTO PARTS MFG. CO. 1815 Trembly Ave., Detroit, Mich. That Armstrong Circuit So much interest has been displayed in the special article. "TESTED INVENTION OF MAJOR ARMSTRONG AMPLIFIES SET 100,000 TIMES." by John Kent, that appeared in RADIO WORLD No. 13. dated June 24, 1922, the publisher decided to put aside a number of copies for those who were not able to get this issue when pub- lished. Copies will be sent, postpaid, on receipt of 15c, or send in your subscription, $6.00, (or one year (52 issues), $3.00 six months, or $1.50 three months, and subscription will be started with the issue containing the article about Major Arm- strong's Amplifier. — RADIO WORLD. M93 Broad- way. Talk by Radio from Coal- Mine Depths British Colliery Teats Prove Successful! and Valuable Data Are Obtained I NTERESTING results were obtained by experimenters at the Baggeridge Colliery in Birmingham, England, a few days ago, says "Wireless World." Ef- forts were made to transmit messages from a depth of 700 yards to the surface. A three-tube set was used. The aerial w^s erected by slinging a wire from a steel hoisting gear 100 feet high to a girder of a railway bridge. The ground wire was clamped to the lower part of a railroad rail. At first the transmitter and its aerial were installed in the steel cage, but considerable screen- ing effect was experienced. Tests were made at various distances down the shaft, and reception was found to be clearer when transmission was .jnade at the lower points. This was thought to be due to presence of structural steel- work, which might have caused screen- ing higher up. Another experiment was made by tak- ing the transmitter along the workings and groundings were effected by bring- ing a length of cable along the floor. The aerial was slung between pit props. Sig- nals were clearly received at the pit mouth, although, owing to limited power of the transmitter, telephony was weak. It was suggested that the carbon in sus- pension in the air was having an absorb- ing effect on the signals. Likes Mr. Miller's Set Result of Trying Out Hook-Up in Radio World, No. 30, dated October 21 EDITOR, Radio World:— We have been trying' out Mr. Miller's H-C hook-up the last few nights and using a U-V-200, but only have been able to get, in less than an hour's time, 2X1, WGY, WSB, and WDAP. We find, however, that the tuning is extremely sharp and can be materially helped by using an .0008 variable with vernier and a vernier rheostat. Last night (November 17), we tried out with two stages of amplification and a Western Electric power-amplifier with horn, with excellent results. .It's just about the simplest hook-up we have tried and, while critical, anyone should be able to work it. In receiving code, however, we do not seem to get the proper increase of signal from amplification when using large coils for high-wave length. We regard this hook-up as a good win- ter-time one; that is, for good radio weather, but doubt if it would be as sat- isfactory in summer time or poor radio weather. This would apply only to long- distance phone broadcasting. It will also be noted that this hook-up treads on the toes of Major Armstrong. — Smith Novotoy Electric, Inc., Char- lotte, North Carolina. Air Service Radio School A NEW Army radio school for train- ing Air Service radio operators and electricians has been established at Cha- nute Field, Illinois. The school was re- cently removed from Post Field, Okla- homa,, and new classes for radio instruc- tion aire being formed. Enlistments for training in radio for the Army Air Ser- vice are now being accepted at Chanute Field, where a six months' course will soon be started. YOUR NEWSDEALER will "mO WORLD to your home. In order to be sure of getting RADIO WORLD regularly, ar, a single issue, we suggest that you either subscribe direct or through your newe- d\ (52 issues), $3.00 six months, and $1.5* three months. Or instruct your newsdealer 1 >RLD regularly to your home each week. Dealers will take standing orders and ar whenever requested. Radio World, 14*3 Broadway, New York. IS YOUR TELEPHONE HEAD SET WEAK? Let me remagnet- CA ize it Goaranteed, * 1 °OU in one day good a* «» new. Pot m 1 rewind for higher oh mags. All radio telephone repairing at mod- erate prices. Mail orders attended to. Dealer* write. ROYS, 101 West 42nd St., N. Y. PATEN! To the Man with an Idea I offer a comprehensive, experi- enced, efficient service for Us prompt, legal protection, sad the development of hit proposition. Send sketch or model sad descrip- tion, for advice as to coat, search through prior United States patents, etc Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable me to accurately advise clients as to probable patentability before they go to any expense. Booklet at valuable Information, and farm far m nearly d request, write RICHARD B.OWEN.Peteet Lawyer $2 Owes Battels*. Wseklestee. D. a 227»-P Weehrerth Bids.. Nee vert OH* / PRICES SMASHED ■sen sale has sraatsd saw Meads end eeesseaere with the ran It that we new iiinsnaoi drasUe re- dactions la ear quaatr Unas. All seeds prspclil head eard far complete erlee list Yeu'B be sur- prised. Yoa'D teU year Meade. A sample ser- ies' Miens: MMPLITB agagMHATIVg VACUUM TUBI ItT Our Piles Otheaj Panel— Bakellt*— fill* drilled. 11.11 12.4S Cabinet at S-ply wesd ta at penal.. l.iS 2-sS ~ ' - — eeaa tie. 7* MS jaltah pouts with ant. Is. IS M Pour switch steps with auk Bach is. .14 .11 amtht Madias pasts. Nlskel plated • »* ., M M Two ewlteh Urns O tte M M 1 filament rhesstst. Highest rode. .Si I. It 1 rarto eeapler. Peurteen tape 2.11 4.SS 1 It plate tarlahle eeadanser Ml t.tt 1 tube eDstet — Moulded 41 M 1 gild eendsneer sad leak It M I phone condenser It .11 I tube eoaket euppert It .It II feat spesbctd tablng O ee .41 M ■ It feet tinned copper leeneettai wire tt At Blueprints shewing detalla to as- semble .It .tt tiTiT tiTtl Other srtMee takes at reaeeoj free ear was pries list are— Detector tubes— Coanlngham — NOT rebuilt tt.lt tl.tt Crystal dotsetor ar eloeed type tt I.SS Transformer — A udlo frequency 1.1 1 4.11 Double elide tuner — knocked dews. Coll wound i. Lit Loom couples— taunted dawn. Cello wound J.7I .... Loose coupler eeeeablod 7.M ll.lt Variometer— Hardwood staters Assembled 1.11 4.M Preet Pone — Ittt eons t.tt t.tt Helioses— 1401 aims |.7f 12.0O Western Bern-Is lltO ohms S.M ll.St Blueprints- rolns detail at 1 step amplifier is M Two step amplifier — knocked down Panel drilled |2.|| 23.M Two etep ampullar assembled. In cabinet |».8« Vacuum tube act In cabinet T"x It". Wired 17.11 1S.II Seed for Hat today or order direct from aha**. Seeds sold lukjeet to retara far rotate ar ax- Shanls. YOU MU8T BE PLEASIO. Radio Parts Manufacturing Co. IS Park Plswe West Detroit, Mich. Subscribe for RADIO WORLD. $6.00 a year, $3.00 six months, $1.50 three months.. Digitized by Google

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RADIO WORLD 29 By Radio Across the Atlantic How the New Langmuir Tube* Will Send the Human Voice in Both Direction* SENDING radio messages across the ocean by means of the tubes pre- sented a contrast of apparatus. The Alex- anderson alternators almost fill the center of the Rocky Point, Long Island, plant, whereas the tubes to be used, invented by Dr. Irving Langmuir, of the General Elec- tric Company, Schenectady, New York, could be put in a suit case. This does not mean that the alternators will be immediately superseded, because the tubes' superiority has not yet been sufficiently demonstrated to permit the scrapping of the larger machines, although the eventual adoption of the tubes is con- sidered inevitable. Their value, says "The Times," New York, will be even greater to wireless telephone development, than to telegraph efficiency, as they were evolved by application of the same prin- ciple that has made the audion tube the most important achievement of those working on the wireless telephone. The human voice already has been car- ried across the Atlantic by wireless, but only in one direction. By means of these electron tubes it is expected that the voice may be sent both ways without difficulty, so that extended conversations may be carried on. This is not exactly the same as two voices talking at once, as wireless communication is made at the speed of light and a word would reach Paris from New York so quickly that there would be no interference with the word coming back. Plans for the development of the new electron tube experimental set were com- pleted in December, 1921, by representa- tives of the research and engineering de- partments of the General Electric Com- pany and the Radio Corporation, and the manufacturing of this highly delicate and specialized set was immediately started in Schenectady, New York. So fast did the work • progress that in May of this year the temporary installation of the set was started at Radio Central, the Rocky Point station, and when Marconi visited the station in July preliminary tests were in grogress under the direction of W. R. C :aker of the General Electric and C. W. Hansell of the Radio Corporation. The set at present consists of three fifty- kilowatt, 15,000-volt, water-cooled, metal vacuum tubes, known in the engineering world as kenetrons, and used as recti- fiers; and six 15,000-volt, twenty-kilowatt, water-cooled metal pliotrons, used as high-frequency converters. For the ex- periment with the tube set one of the new mile-and-a-half-long antennae, suspended from six towers, 420 feet high, was used, and the tnbe set succeeded in developing and sustaining in the antenna a current of the strength of 350 amperes. About 600 amperes has been used with the Alexan- derson alternators, but it has been found that with the development of wireless ap- paratus a lower amperage may be used. The most interesting feature about the experiment to the engineers conductirg it was that the receivers and senders did not know that the change from alternators to tubes had taken place. There is little dif- ference in the tone, the tube tone having a sort of companion wave sound, a kind of wireless echo, which, however, proved to If yon did not get a copy of Radio World No. 1, tend tu $6.00 and we will send yon this paper for one year, and ■tart it with our first issue, which will be mailed you as soon aa possible after re- ceipt of order. be almost indistinguishable until it was pointed out to the receiver. The switch from alternators to tubes was made with- out notifying the senders or receivers at 64 Broad Street, and although the man receiving messages from abroad sits on the other side of a table from the man sending, the receiver did not notice the change in the New York plant signals. R-C CABINETS Mil Hi Mi few—Tie Qaallty Flat*. M* OrtS- lao 1 eaael* rer attaoaleg reaalr.*. HlateJ Me. RETAIL PRICKS 1x« «.«• 7x14 sa.oo 7x10 tt.75 7x11 7x*l S4.M it y— THE R-C MILLS S* E. :>e •*.. Nee Vera, M. V. RADIO WOKLD) 3 BETTER LOUD SPEAKERS AT HALF THE I'Hl'AL PRICE REAL CABINET TYPE- Pmrltl — Beaatifel— TONE INCOMPARABLE We auao a nwlm aae kurt-rnkkta tmhtm.. All SPIROLAS ar* **M aadar aheotarte ivaraatt* b> eel la eahme aa* far art— la ' twiw their arlee. SPIROLA CONCERT— eeeeMa wit* ealtt-la aaK aa* afro] rata* la attaaa la ah: aaTTtl v aaeekrta ■■aiv-aa aa* Maa any ether ■Mm «f aaa—. Flaiak: eat. (Meea 00) er ■aaeaaay (Cat), emuaa $12.50 laar*v*a ty*a with waanta teae atauaker far aae* $4.85 er anaeaaay (DM), areaaa laraat era.o« $3.85 job')".' ■■amey » "AU w«*" waaeaai aiaeanta nieaaaivaj emtirn ue that lo New Jeraey I bet In aa" far veil u tbe L'nlTeralty of Wlenmeln aixl Chicago, where** la Jl'witfaaj. they bate .bunih. J.. I'enaila. It if nothing -jaueual u> bring lo zkhenecuOy. Detroit. Chicago, Pin Newark and tbe Arlington Uaje elgnela. direct, and la Mobile. Ala.. New art le brought In daily. laaaja el |*a||a|a»Bl Ule "A" Ware" Coupler, which I* guaranteed with awaweee an laMMuawaa *a uKxiry tMca to operate aa adterUeed Look lot the tradeaaark. "All VVaee." aa tha rotor, ale* the aU efficient hooa upa la ti« ixn £Q (\f\ M> aaBrleel Hook-apa aret opea ree-elpt of I Or. «P«7*V\/ atemp* er Ar** with aatrh "AO Wmtm" Teaplrr OlARANTKKO WITH AM AB8QLITE MON E V -BACK Ol AR VNTK1 Capitol Plionolier Corporation m™ LefOrettey HUaal Vetk Clay Give This Set for Christmas A Real Tube Set »27M With 2-8Uge AaapUaer The AM*«vbly $54 A Real Tube Set For the Price of a Good Crystal Set A high-grade tub* set that costs less than price of parts used. Super-sharp tuning through double circuit and LiU-wound rotor. All the fun of assembling— but correct assembling made absolutely certain and simple by means of concise and easily understood instructions. The set is supplied with the 7-inch x UMnrh hard rubber panel, drilled and engraved and fastened to the handsome mahogany-finished cabinet; all parts are packed in the cabinet and include all connecting wires cut, bent, and turned ready for soldering; instructions for assembling are supplied. Securely packed in shipping carton. A set that gets the highest results at the lowest price. // your dealer can't supply you, send cheek or tnoncv order. Dealer! write bow for apeeial price* on immediate Christmas deliveries RADIO COURSES, INC. (Dept. RW3), 552 Seventh Ave., New York

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT So A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS Is RADIO WORLD on the news-stands tan days after copy reachee as. Tb rata lor tbJa RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. per word (mahm af It words, including sddrooo). M detcount for 4 consecutive Insertions, 15% (or U oonaoenrhro loiortlain (i (Maths). Chances will ba made hi ataadbut -'tt-Wlr? advs- if cony is I it si l si at this office tan day* before publication, RADIO WORLD CO, MM Broadway. N. Y. C (Phono, Bryant 47MJ AT LAST I Your chance to learn to fly snd fet into aviation. Write to Varney Aircraft Co., eoria, III., for particulars of this great oppor- tunity. - RADIO FANS: Have you read of the won- derful new all-wave Radio Frequency Amplifier invented by Doctor Miller of the Naval Radio Research Laboratory. Bureau of Standards, Wash- ington, D. C. ? We manufacture this device under license. Hay be added to your present set, giving wonderful results on distant stations, or may be made up into loop receiver sets with extreme range ana beautifully clear reception, for home or automobile use. Besides being the best amplifier on the market, the Miller covers all waves at equal efficiency. Price, $6.50 per unit. Details free. Coast Radio, Inc., El Monte, Los Angeles, Calif. WE PASS samples or circulars, lc each, to houses direct. Lady Canvassers. We mail your circulars, 25c. a hundred. Guaranteed names of our mail order customers. 75,000 up-to-date lists, $2.00 thousand; 7,000. $10.00. C. H. Davis & Son News Agency and Mail Order Distributors, 614 W. Jefferson, Greenfield, Ohio. EISEN Supersensitive tested Crystal No buzzer test necessary. . If not satisfactory, return crystal and money will be refunded with mailing charges. Mounted, 50c.; unmounted, 45c. Special Prices to dealers. Wm. Hafner, 726 New St., Camden, New Jersey. "MUSIC composed" to words. Bauer Bros, (formerly of Sousa's Band), Oshkosh, Wis. MILLER AUDIO FREQUENCY transformer eliminates howling. Entirely satisfactory on three stages. Price $5.00 postpaid anywhere in U. S. RADIO SALES CO., Box 1144, Bethlehem, Pa. RADIO MAN with two years' experience de- sires position. Herbert Listerville, New Bruns- wick, Canada. MAKE LONG RANGE INDOOR AERIAL. Instructions with small working model, fifty cents. RADIO SPECIALTIES CO.. Box 34, Med- ford Hillside, Mass. HAVE YOU SEEN IT 7 My unusual, fully il- lustrated radio catalog is complete. Saves you money. N. E. Ristey, Spring Grove, Minn. ' THREE STAGE AMPLIFIER — Mounted in Handsome Cabinet. In A-l condition. Big BAR- GAIN at $40.00. Write for particulars. Earl Wright, Cole Camp, Mo. ATTENTION! You invent it Let us mske it Models, dies, manufacturing. Sheldon Tool Co./ Rosedale Station, Kansas City. SALESMEN that have been or are calling on electric or radio trade, see Mr. Rice, 6311 N. Clark St, Chicago. EXCHANGE letters with new friends every- where. Pleasant pastime. Information for stamp. Smith, Box 3125-M, Portland. Ore. ISSUES OF RADIO WORLD from April 1 to Oct. 7 (27 numbers) for 15c a copy, or the whole lot for $3.11 Or send ns $6.00 for one year snd start with the first number. RADIO WORLD, 1493 Broadway, New York. EDISON B. BATTERY UNITS— One positive and one negative plate for 10c. 18 sets will make a 24-volt battery. Wilkinsburg Wireless Shop, 711 Penn Avenue, Wilkinsburg, Pa. BOOST RADIO. Wear a pin or button. It shows you are progressive. Designs snd esti- mates furnished by official club jewelers. TVs Rankin Co., Radio Dept., 1118-20 Chestnut St.. Philadelphia, Pa. HELP WANTED— MALE EARN tils to $St Monthly, expenses paid, ss Railway Traffic Inspector. Position guaranteed after 3 months' spare time study or money re- funded. Excellent opportunities. Write for Free Booklet G-151. Stand. Business Training Inst, Buffalo, N. Y. DIALS, 3-inch, genuine hsrd rubber, raised or depressed scale, white or gilt lettering. Drilled for Vt and % inch shafts. 60c. each. 3 for $1.50, postpaid. No stamps. RADIO SALES CO., Box 1144, Bethlehem, Pa. OLD MONEY WANTED — $2.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book, 4x6. You mav have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave. 83, Le Roy, N. Y. ACT QUICK SALE. Oak Cabinet. 6jc6%xl8, with genuine 3/16 Celoron panel, $3.75. Haunt Radio Supply Co., 2332 Ogden Ave., Chicago, 111. MEN WANTED for detective work. Experi- ence unnecessary. Write for details explain- ing guaranteed position. J. GANOR, former Gov't Detective, St. Louis, Ma PARAGON, RA-16 receiving set for sale with three steps of amplification, in a neat cabinet; three power tubes, three amplifying tubes, six volt Everready storage battery, four 22V4 Bur- gess B batteries, brand new 3000-ohm phones, three dollar lightning switch, microphone and a complete charging outfit. Will sacrifice st $300. Write Edward Hoffman, 1719 E. Washington, Ft Wayne, Indiana. Manufacturers of Rogers Radio Receivers and Rogers Receiving Radiometers. Rogers Radio Company, 5133 Woodwortb. Street, Pittsburgh, Pa. YOUR HOROSCOPE, business, changes, social, matrimonial prospects. Send birthdste and Ten Cents (stamps) for remarkable test reading. ZANY A, 202- J, West 105th St, N. Y. NEWS AND GOSSIP OF THE STAGE— Sand 10c for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. HM year, $2.00 six months, $1.00 three months. New York Star Co., 1493 Broadway, N. Y. Exchange Jolly Interesting letters through our Club I Stamp appreciated. Betty Lee, Inc. 4254 Broadway, New York City. j LOUD SPEAKER FOR ANY CRYSTAL SET. Hear music over entire house. Easily con* structed by amateurs. Eliminates Battery. In- structions complete. 25c. Catalogue Free. Rep- resentatives wanted. STEINMETZ WIRELESS MFG. CO., EASTEND. PITTSBURGH, PA. FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO." Write today for complete list of premiums snd our special snh- tcription offer. "RADIO," Pacific Bldg.. Sea Francisco, CaL WE NEED RADIO WORLD, dated April 8- and August 5. If you have copies yon don't re- quire, mail to this office and current issues wU be sent you for them. RADIO WORLD. 1493 Broadway, New York. Are yon familiar with all the radio sj leasts used in the vsrious hook-ups published in Radfe World? If not, secure a copy of Radio World No. 24, dated Sent 23. In this Issue was a com- plete table of all important symbols seed la reams construction and testing. Send 15 cents far a cony, or $6.00 per year, snd have sosseilptlsa start with that issue. RADIO WORLD. MM •roadway, New York City, If. Y. No More "Distant" Places Even to the Remote) Lumber Camps, Radio Brings Tidings of the Busy World. RADIO may be helpful in many ways to the city-dweller, but it can never have for him the real meaning that at- taches to radio in the wilderness. Says Henry Smith Williams in "The Ameri- can," New York. Imagine yourself spending the winter in a lumber camp a hundred miles or so from any permanent habitation. Better yet, imagine yourself a lumberjack working month in and month out in a northern logging camp, which you leave Attention, Newsdealers You should keep a good supply of back numbers of RADIO WORLD on hand all the time. It has been the experience of many dealers that a purchaser of RADIO WORLD for the first time will almost immediately want the back numbers, some of which are already out of print 11v„;omf of wh''ch are difficult to Ret. THE ^BrCtSP,EJlWII-r- ORNISH BACK NUMBERS T?,JSK^TERS ™RECT OR THROUGH THE AMERICAN NEWS CO. AND ITS BRANCHES" Dealers should hold their unsold copies for a reasonable length of time. RADIO WORLD of October 28 contained a full page of contents of back numbers to that date. 15 cents per copy: ?££ nm1 "umbers for $1.00. RADIO WORLD, 1493 Broadway, New York. at most twice in the year1— on Christmas and on the Fourth of July. For months together you are shut out from all physi- cal' contact with what we ordinarily speak of as "the world." No newspapers, no letters, no rumors even of what is going on a hundred miles away. And then imagine that someone in- stalls a radio outfit, so that you can listen nightly to the news of what is happen-, ing all -over the world, and -to concerts ' and lectures. You are no longer isolated. You are up to the minute in your knowl- edg of affairs. This is just what has happened in many lumber communities. Away out in the forests of the Coast Range in Ore- gon and Washington, the Hammond Lumber Company has installed power- ful receiving sets in more than twenty, of the logging camps. The lumberjacks listen in on San Francisco and Portland and Seattle, and never lack for entertain- ment. A highly interesting feature of the in- stallation of these radio-receiving sets is the preparation of a pair of poles to support the antenna wire. Trees about 300 feet high and, perhaps, six or seven feet in diameter are selected. The lum- berjack, with the aid of a rope and a pair of climbing irons, runs up one of these trees like a squirrel, lopping off the limbs on every side until the tree is like a telegraph pole. Then a wire, perhaps a thousand feet long, is strung between two trees at a great elevation. A lead-in wire connects with the radio apparatus in tent or cabin ; and after tuning diffi- culties are overcome, everything is in readiness to receive messages. At Your Service! There appeared in RADIO WORLD, dated April 1, 15, and 29, the following art idea. April 1— A 500-Mile Radiophone Employing a 5-Watt Tube, by Frank A. HahneL "Tell Me, Please, How Will This Set Receive?" by E. L. Bragdon. Short Cuta in Receiver-Cir- cuit Design, by O. C. Roos. Making a Short- wave Regenerator, by Fred. Chaa. Ehlert- April 15— First Principles of Electricity as Applied to Radio, by John P. Miles. Your Storage Battery, by E. L. Bragdon. What Makes Radio Possible, by Edward Linwood. Ground Connection as Vital as Antenna, by Fred. Chas. Ehlert. April 29— Valuable Pointers on Aerial Con- struction, by Edward Linwood. What la Meant by Tuning, by E. L. Bragdon. Radio- Frequency Amplification and Regeneration, by Frank Armstrong. Honey-Comb Coils and Con- densers, by Edward Linwood. Charging the Storage Battery, by E. L. Bragdon. How to Construct the Variocoupler, by Frederick T. Rum ford. Each copy sent on receipt of 15c. per copy, or the three copies for 45c; or better still, send your subscription beginning with sny one of these numbers, and we will send this paper for 52 issues, and you will then have a complete file Tor ready and constant refer- ence. RADIO WORLD. 1493 Broadway, New [%teed by ^OOgle

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RADIO WORLD Do Yon Llk* Clear Tone— Sharp and Distinct T If so try MARSH'S Vernier Variable Condenser AT LAST Mad* la Three Styles. Dial Knee and Screws Complete. Fully Guaranteed. tT-Plate • S8.50 tS-Plato * S4.75 U-Plate • M-M Mall order* promptly filled. P. P. Marsh, 145 NicoU St NEW HAVEN, CONN. If you haven't seen the TUNIT jrou're missing something Big. Skip Owners' Radio Service, Inc. 80 Washington St, N. Y. "BE C O" RADIO FREQUENCY SET US to 500 Meter* 3 Radio Frequency S Audio Frequency and Detector All on 4 Tubes Bissell Engineering; Company MI-IS7 W. 04th STREET. NEW YORK RADIO SALESMEN! A Rare Selling Opportunity For Live Wire Men Handle Grewol Detectors in territories not opened. Write for full 'particulars RANDEL COMPANY t Central Are. Newark, N. J. New Device Stops Static Functions on an Antenna at Any Wave- Length, Declare* the Inventor, Dr. B. C McCaa. PREVENTION of static interference in radio reception has been solved, ac- cording to Dr. B. G. McCaa, of Ephrata, Pennsylvania. Dr. McCaa, who has been working on static problems for over four years, is not a doctor of radio or any other science, but a "simple M. D.," he says. He took up X-ray and high-fre- quency work in medicine and became a radio "bug" ten years ago. In a communi- cation to Radio World, he describes his invention for the killing of static as fol- lows : "The antistatic work was taken up early in 1918, and, in the course of four and a half years of search and testing, three systems only, out of many studied, have shown any merit. Let us designate them as A, B, and C. "During July of this year, tests were made of systems A and B, in combina- tion, on the commercial-telegraph chan- nels of the Federal Telegraph Company in California. Repeated observations made by many engineers showed signal to static ratios of 200 to 1. Static of 3,000 to 6,000 times audibility was reduced to audibilities of 10 to 50, and signals 200 to 250 times the strength of the static received at the same time. "System A reduced static to a one-to- one ratio, and system B improved the ratio as given above. , "From the practical result, i. e., read- ability of signals, operators could take solid copy on 'stuff' that could not be copied on standard receivers. "System C is a more recent develop- ment and replaces system A, as it has proven far superior to A in many respects. Combining C and B, absolutely static free signals have been obtained in the presence of nearby electrical storms. _ "All the systems are designed to func- tion on an antenna and do not depend for their operation on the vagaries of directional propagation or some mysteri- ous 'origin' of static. They may be used on closed coil or loop reception as well as on ground or water wires. "Systems A and B in combination are adapted solely to radiotelegraphy and may be used at any wave-length. "System C operates at any wave-length and possesses the decided advantage of being applicable to radiophone work at any wave-length. It has been proved to function at 360 meters. The device is sim- ple; it has but one adjustment, which, when made, remains fixed for all time like any other tuning adjustment." Radio Goods Active TJOLIDAY business is taking on more *■ life in electrical goods and some cities report shortages of certain stocks of heat- ers and ironers. "Electrical World" will say tomorrow: "Central station activity in making line extensions is taking much high tension equipment. Motors in all sizes are moving well." Radio jobbers report better sales, saying that a lot of the business is going to parts and head sets. Vacuum cleaners are also in demand and washers are more active The mild weather and improvement in the coal situation has slowed down the sales of heaters but purchases are frequent. — "The World." VARI0 COUPLERS GEM $1.25 List We alto maJtm $ other ttylma That List $2.50 up Jobbers — Dealers — Agents Write (or Discounts Jewell Radio Sales Co. 90 West St^ RNew York Gty The Latest and Most Essential Part of an Efficient Tube Set Variable Grid Leak and Micon Condenser (Combined) Obtainable In an unbroken ran re from sero to 5 megohms — all . Intermedial, points. Fixed rapacity — .000SS M. T. Improves your set wonderfully by Clarifying Signals Lowering Filament Current Increasing Battery Life Eliminating Hissing Price Only $1.00 At your deal en — otherwise send ns par- chase price and yon will be supplied without further charge. - Manufactured by CHAS. FRESHMAN COMPANY, Inc. 97 Beekman St. New York City Home of Micon A Antenella AETACO CRYSTAL SETS $225.00 Wireless Specialty— Crystal and Audion, 150 to 3.0U0 meters. Our Price Today ttO.M $25.00 Baby Lawson Crystal Sets— Complete Arrial Wire Insulators and Phone.. $17.00 Aeriola Jr., Complete $22.75 Less Antenna Equipment $17.50 (25.00 Polalc-Green Complete $15.0* tOO Queens Variometers $2.50 00 Polak-Green Variometers $2.50 00 Baldwin Variometers $3.25 Others As Low As One Dollar t50 Baldwin Coupler, Super Type.... $3.50 50 Emco Vario-Coupler $450 00 Queens Vario-Coupler $2.50 ' Phones $8.00 Federal Phones $4.50 $1500 Western-Electric, No. 509W $s.S0 $12.00 Kellogg Phones $740 $8.00 Auth $4.00 Rheostats 1.50 Paragon Rheostat 70c .1.50 Klosner Vernier 00c 95c Keeps Vernier 75c 1-00 R,gal 7Sc 3.00 Roberts 40c 1.25 Boston Porcelain Base 50c Amplifying Transformers $5.00 General Radio $».7S $7.00 Jefferson $425 $6.50 Murad Radio Frequency $9.00 $3.00 Baldwin Radio Frequency $1.25 $2.50 Brach Lightning Arresters $1.50 $1.50 Argus Lightning; Arresters Mc $2.00 Keystone Lightning Arresters $1.00 $2.00 Beginner's Practice Keys 75c i ! Postage Extra. Catalogue, 10 cents. American Electro-Technical Appliance Co. Mail Orders 235 FULTON STREET 1037 BROADWAY NEW YORK CITY SEND 7JB THE NAME OF YOUR RADIO CLUB A,5? tn* name* of your president and other officers. We want to add these to a list of radio clubs and officers we are preparing for publication In an early Issue. RADIO WORLD. 1493 Broadway, New York. /^~>

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RADIO WORLD JMDIO RESTORES Lttuoraiory aiiu oervice v» uik rruvc uic Superiority of the RADIO STORES VARIABLE CONDENSER A Few Distinctive and Exclusive Features Concealed Counter Weight Under Dial Brass Studs Through Aluminum Plates and Die Cast Shaft Held in True Center Through Brass Bushings Binding Posts Mounted on Separate Metal Straps In No Instance Is Insulating Material Tapped — Metal Inserts Throughout Precision Workmanship — Best Engineering Design 23 Plate. .0005 Mfd. Max. to Min. Cap. Ratio 2S-1 $4.25 1 43 Plate, .001 Mfd. Max. to Min. Cap. Ratio 46-1 $4.75 RADIO STORES TORPEDO PLUG ALWAYS DEPENDABLE! A I I conductive parts of heavy machined brass, insulated through* out. Screw binding post terminals, with separate anchor for tall of cord. Designed to In* sure rigidity, dur- ability, strength and lightness. The Radio Stores Torpedo Plug is one of the series of their products, de- signed and constructed to meet the requirements of the critical user, st the right price. RADIO STORES MESSAGE TO DEALERS Oct your name on our mailing list- — famous for opportunities and new inventions — a penny postal gives you this profitable service, catalog and data booh. We are also distributors for Deforest and Dlotograph products. Full stocks for immediate delivery. UNION-RADIO PHONE TIP JACKS (Patant Applied For) They are valuable wherever head phones are to be used. Especially convenient in connection with CW circuits. Countless uses have been found for them. The use of binding posts to connect phone tips has always been unsatis- factory. It is difficult to keep the tips from falling out of the binding posts. These Union Radio Jacks will accommodate any telephone cord-tips front (Ontaida) viBW manufactured. To mount them on any panel, just drill a hole, using a 7/64 drill, insert the bushing, and screw on the lock nut which holds the combination tension spring and soldering lug in place. * The tip when inserted is firmly held. And a good electrical connection is assured at all times. These Jacks eliminate the buying of an expen- sive telephone plug and Jack. Ideal for experimental circuits or in any part of a set where quick changes are needed. They accommodate wire up to the thickness of telephone tips. 25c A PAIR We also manufacture complete receiving sets, 2 step amplifiers, variable condensers, receiving vacuum tube receptacles, condensite dials, etc. Our catalog M, "Radio Apparatus," sent on request. WHOLESALERS AND RETAILERS Write for our liberal proposition. Sample! of our "Quality Products" sent on request. UNION^RADIO-CORPOFIATION 200MT.PLEASANT-AVENUE,-^NENVARK-'NJ. NEW" YORK- OFFICE ** 1 16*WEST"'\52-»STREET. mist REAR (Inalde) VIEW Digitized by Google

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CHRISTMAS NUMBER W , DECEMBER 9— 15c LLUSTRATED WEEKLY This Is a Radio Christmas ! Why Radio-Frequency Amplifies Signals Santa Clans Tune* In Million* of American Homes 1 More Records by the DX Night Owls

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RADIO WORLD There Is NO OTHER— WITH A large map, size 2 feet by 3 feet printed in two colors shoeing location of eOery 'Broadcasting Station in United States and Canada; change of time area and location of each of the nine districts, THE THIRD EDITION CALL BOOKl ALL UNDER ONE COVER An Official List of all Amateurs, Special Amateurs and Broadcasting Stations of UNITED STATES AND CANADA — ALSO How to Construct and Operate a Honeycomb Coil Set, Detector and Two Step Amplifier PRICE, $1.00 COMPLETE (DO NOT SEND STAMPS) Order from your dealer — If your dealer hasn't them, tend direct. DEALERS WRITE FOR PROPOSITION RADIO DIRECTORY & PUBLISHING CO. 45-K VESEY STREET NEW YORK, N. Y. STANDARD PARTS The Best Xmas Buy Special Price for Month of December Western Electric, illustrated Federal, MM ohm ***\ Kellogg, MM ohm *••» Auth •. **• All in original sealed boxes. The efficient result depends an a good bead-set. Paraxon Rheostat, for Panel or Table MJt Klosner, Vernier, Special Type for Detector.. jM If you want rood tuning' and a long life for your tubes, select either rheostat above. Greatest sat- isfaction. Large Sire Variometer, illustrated, a Bald- Queens Make, Coupler or Variometer. 2J» -IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIHHHIIIIIIIIIIIIIIIIIIHIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIE 1 What Shall 1 Give HER For Christmas? ( ~ The biggest treat any woman of refinement, who is ~ 2 most particular about her appearance, can have is — Les Etoils Skin Food $1.25 L ■ Arc - En • Ciel ideal cleanser $1-25 Kanti Face Powder (four shades) $1-5° Rouge Superlative $100 ieunesse astringent $1.50 farvelous wrinkle remover and cleanser. Amber Royal Perfume $4.00 Eye Lash Grower $1.00 (11 .St Mme. Anita Kanti's Christmas Beauty Box' RADIO MAP LATEST EDITION Featuring:— District Divisions, Time Divisions and All U. S. and Canada Broadcasting Calls 35 Cents Above Map Given FREE with $5.00 purchase until Xmas. I Mme. Kanti's wonderful preparations have been the favorite for years and used by the famous beauties of both Paris and New York. Among Mme. Kanti's personal clients can be named the reigning stage and screen stars. ABSOLUTE SATISFACTION GUARANTEED Address — *1A MME. ANITA KANTI 1 «P 1 V 47 West 42nd Street, New York City = fiiiiiiiiimiiimum urn iiiiiiiiiniiiiiiiiiiiiiiiiiii mi iiiiiiiiiiiiiiiiiiiiiiiiiiiir. This entire assortment in beautiful Christmas Box will be delivered prepaid receipt of All sales prices in November issues of RADIO WORLD are good until Xmas. Postage must be included with order. Checks must include 10c. exchange and please have them certified. All goods are shipped P. P. insured. . RADIO DISTRIBUTING & AUTO SUPPLY COMPANY 64 West 66th Street, New York City Phone Columbus 8584 Broadway igitized by *-6tl ibway

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VOLUME TWO OF RADIO WORLD [Entered m second-class matter, March M, 1923, at the Poet Office at New York, N. V., ander the- act of If arch 3, 1»7»J A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennesey Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 47M. VoL II, No. 11. Whole No. 37 December 9, 1922 15c per copy, $6.00 a year Radio Now Used in the United States Congress (C. International News Reel) u-ding- delivering hie words lor broadcasting- The square discs in front oi the reporters are President Hardin* delivering- his recent message to Congress. The bell-like apparatus hi also microphones to catch their orders. which catch Digitized by Google

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4 RADIO WORLD , . - - Radio Frequency fransformers - \f ( Figure 1— Schematic diagram of a five- tuba radio-frequency receiver. The firat three tubas and tranaformere are the radio- frequency amplifiers, the next tube ie the detector, and the last tube is a one-state of audio-frequency amplification. A loop aerial is used. Suggested by George W. May. Drawn by 3. Newman. Why Radio-Frequency Amplifies Signals By Donald Van Wyck RADIO-FREQUENCY ampli- fiers are attracting considerable attention. Radio fans who are unable to erect a satisfactory antenna may improve the strength of incoming concert music, or increase hearing range, by means of radio-frequency amplification, audio- frequency amplifi- cation, or a combination of both. In cases where the receiving station is near the transmitting station, the energy received is usually sufficient to reproduce sounds without radio- frequency amplification. When the re- ceiving station is more remote, the signal must be built up, or amplified, before it passes through the detector and the stages of audio-amplification. If radio amplification is not used, audio-frequency amplification in such cases is frequently of little use. In the first place, the fundamental differ- ence between radio-frequency and audio-frequency amplification is far from clear to many of the amateur operators of to-day. As the names imply, both instruments amplify the signals received from distant broad- casting stations; but they do it in a widely different manner. The audio- frequency method, for instance, ampli- fies whatever the detector delivers to it and, therefore, increases the volume of sound in the head telephones. It is obvious that if a certain signal is too weak, by the time it reaches the re- ceiving antenna to operate on the de- tector, no amount of audio-frequency amplification will make it audible in the head phones. Radio-frequency amplification, on the other hand, goes straight to the root of the trouble. The radio-frequency tubes precede the detector in the circuit and confine their work to the radio impulses in their original form. In accordance with the natural action of the vacuum tube, these impulses are successively strengthened by as many tubes as de- sired. When they are deemed suffi- ciently strong they are passed to the vacuum-tube detector for conversion into currents of audible frequency. Once audible sounds are produced, audio-frequency amplification may be relied on to obtain the desired volume. The connection between the ampli- fying vacuum-tubes may be merely a wire or, possibly, a very high resist- ance; or it may be some form of a Figure 2 — Another schematic sketch of a radio-frequency receiver. This diagram shows two radio-frequency tubes and one detector-tube in operation. This circuit should produce unusual results on DX work. Suggested by George W. May. Drawn by S. Newman. transformer. The first method, that of a direct connection, is unsatisfac- tory and is never used in actual prac- tice. The second is fair and has re- ceived more or less recognition. The third method of using transformers is the most satisfactory and is most gen- erally used. The transformers may be of the air-core type or of the iron-qore type, which has two independent coils known as primary and secondary, re- spectively, mounted on laminated legs. The iron-core amplifying transformers give the best results and, paradoxically, also give most trouble to the un- initiated. The amount of iron in any trans- former is dependent on the frequency of the current which is passed through the windings, and the higher the fre- quency the less the iron used. Since the iron must reverse its polarity with each reversal of the current, this indirect ratio may be explained easily. With audio frequencies, such as are encountered in signals after they leave the detector, the design of the trans- former is not difficult. But when it is remembered that the radio-frequency of a 200-meter wave runs into the millions of cycles per second, the com- plexity of the task which confronts the designer of radio- frequency amplify- ing transformers is realized at a glance. The design of the radio- frequency amplifying transformer would not prove a thorn in the sides of the manu- facturers if the commercial phase of the question could be side-stepped. It is not much of a problem to construct a transformer which will function very well in a narrow band of wave lengths : say from 200 to 300 meters. But such a device would not meet the sanction of most amateurs because they do not wish to be put to the task of changing transformers for the various wave lengths. Beware of all-wave radio- Digitized by Google

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RADIO WORLD 3 Capacitively Coupled Receiver for DX Work CAPACITIVELY coupled cir- cuits are those in which con- densers are used to connect primary and secondary circuits. By varying their values, a set may be placed in tune with a transmitting sta- tion. This type of coupling is said to be electrostatic, since condensers func- tion only by reason of their electro- static field. A simple circuit shown accompanies this article. This dia- gram, when used with such a receiver, will operate successfully on short waves. It is seen that the primary circuit is essentially a parallel resonant circuit, as distinguished from the series of resonant circuits that are common to the direct and inductively coupled (Continued from preceding page) frequency transformers. They will not function. Several schemes have been tried for circumventing the natural limitations of the radio-fre- quency transformer. One has the division of the windings in sections with suitable taps brought to the sur- face. By means of either binding posts, or a movable contact-arm, the transformer is tuned to the particular band of wave lengths to be received, and, therefore, the loss incident to us- ing a transformer designed for one frequency on a vastly different one is partially avoided. The other scheme provides a series of transformer units to be plugged in and out in accordance with the tuning. The most common radio-frequency transformer on market resembles the audio-frequency type and is designed to function on a band of wave lengths from 200 meters to 450 meters. Accompanying this article are two schematic diagrams of practical radio- frequency circuits which consist of three stages of radio-frequency and de- tector; also, one stage of audio ampli- fication. For the antenna with this par- ticular set, I used the loop aerial as explained by me in Radio World, No. 33, dated November 11. The loop aerial (Figure 1) gives the marked advantage of eliminating interference and practically makes a directive an- tenna a compass loop. The loop aerial will function satisfactorily if used with this three-stage amplifier. Figure 2 shows a two-stage amplifier of the radio-frequency type with vacuum-tube detector. Any one contemplating the building of this set will find that it works far better than some others. By Arthur O. Curtis circuits. Sharp tuning is accomplished more successfully with this type coupled affair than with any other, and it is somewhat more efficient than other types. Adjustments may be said to be more critical and, generally, there are more adjustments to be made with this type set than with any other. The Condensori may be used to a treat advantage by employing a capacitively coupled receiver. The above •chematic diagram shows such a circuit. The condensers act in this circuit as a coupling between the two coils. Drawn by Arthur O. Curtis. three variable condensers C, CI, and C2 are of .0005 micro-farad capacity. LI is the primary inductance coil and L2 is the secondary inductance coil. The tuning is controlled by C2, while C and CI act as the coupling control. The primary (which is L) consists of forty turns of No. 24 cotton-covered wire wound on a tube 3yi inches in diameter. LI has 30 turns of No. 22 cotton-covered magnet wire wound on a tube iy2 inches in diameter. The coils, when in operation, should be placed at least four inches apart. The degree of coupling is determined by the amount of capacity of C and CI. Broad tuning can be had by increasing the capacity. Small capacity affords sharper tuning and minimizes inter- ferences. The secondary coil in the detector circuit is of standard type and is used to obtain satisfactory results. Changing the capacity settings for these coupling condensers does not change the resonant frequency of the circuit, but merely changes the amount of energy transmitted from the primary to the secondary through the condensers. Take Care of Your Storage Battery II-. faciei & Herbert, N. Y.) The storage battery— these cells of electrical energy are of vast importace. Most of the receiv- ing outfits, t-day, using vacuum tubes need such a storage battery. The storage battery la rather a delicate affair, even if it does weigh a lot. Care must be taken that it does not deter- iorate quickly. With good care a battery for radio work should last several years. The above photograph shows how to keep a battery clean. A clean battery will prevent short circuits. Digitized by Google

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6 RADIO WORLD Efficient Crystal Set at Small Cost By Charles H. Plath Figure 1— Simple circuit with a slide tuner. This will receive phone reception up to a certain limit. Both sketches drawn by Charles H. Plath. W J rad'° broadcasting be- v\/ coming more popular, many » ▼ people are willing to spend a small amount of money in order i break into the radio game. For such people, the crystal set still holds its own. There is practically no upkeep of expense as its cost is low. At any rate, those who break into the game, if it does nothing else it will turn the most disinter- ested radio prospect into a "bug." Radio waves are passing through and about us all the time. We can- not hear radio waves without the aid of instruments. No matter what type of apparatus one decides to purchase, it is worth while to pur- chase the parts, or units, that may be added to from time to time as one's interest increases. For any type of receiver, we must have some sort of an aerial. My experience has taught me that, for receiving purposes only, nothing can equal a single-wire aerial about 75 or 100 feet long. This wire must be about No. 14 B and S gauge. When erecting it, insulators must be used to prevent the wire from losing its energy and, possibly, becoming grounded. Once it becomes ground- ed, all radio waves, or energy, will be grounded and no sounds will be heard. This mistake must be avoid- ed, and a careful examination should be made when erecting the aerial. Insulators should be placed at all points where the wire may come in contact with some metallic, or con- ducting object, such as a metal roof, damp surfaces, and metal stays or guy wires. There should be pro- vided also sufficient wire to reach from the instruments to the nearest cold-water pipe. Next secure a single-slide, or two-slide tuner. With this piece of apparatus you will be able to tune in the stations you desire up to 600 meters. Figure 2— When tape are used, two switches are necessary in a circuit — one for the large steps of Inductance and the other for the small steps. By adding a crystal you will have the simplest possible apparatus for reception. This is shown in Figure 1. A pair of phones, or a single phone, is a requisite for sets both large and small and care should be taken for selection. They should be fated at from 2000- to 3000-ohm phones. Phones should be of the best materials and most carefully made; therefore, if your means are limited it is better to buy a single phone of known quality. Two sliders on the coil will pro- duce greater selectivity. They op- erate similar to an autotransformer — the turns between the aerial slider and the ground end of the coil may be considered as the primary, and the turns from the ground end of the coil to the other slider may be con- sidered as the secondary. A vari- able condenser may be connected across the coil to sharpen the tuning. Still greater selectivity may be obtained by employing a loose coupler as shown in Figure 2. Here there are two circuits. They must be tuned to resonance with each other and the incoming wave. The circuit in which the aerial, ground, and one of the coils is connected is called the primary, or open cir- cuit and the circuit that con- tains he detector and phones is called the secondary circuit, or closed circuit. This also takes in the other coil. Loose couplers are so constructed that the secondary may slide out of the primary. This- relationship between the two coils is known as the degree of coupling. Radio Is the Biggest Show on Earth The performance: Complete grand operas, baseball and football — play by play; we can even hear the bat strike the ball, hear the crowd cheer. In an instant, zve are at the ringside! There is a prize tight on. We can almost hear the knockout wallop — get the thrill of things as they happen. And, on Sunday, the entire service at one of the leading churches. News, amusement, the most interesting: things of the world, are brought instantly into our own home by radio. Let every owner of a radio-receiving set who knows the joys of this, the greatest of all amusement devices, invite some friends into his home during National' Radio Week, December 23 to 30, inclusive, and so bring joy and happiness into an- other's life during the joyous Christmas season. That's what Christmas is for— to bring happiness to others. The object of National Radio Week is to double the number of radio fans. Let every radio enthusiast make it his business during this week to enthuse another — to- bring a radio-receiving set into a home" that now lacks the thrill of being in con- stant, instantaneous touch with the great actors on the world's stage. A radio receiving-set costs less than a good phonograph; also, the upkeep is much- less. _ There are no records to buy, nothing to wind up — and an entirely new program every hour. Radio amuses and interests every mem- ber of the family with scientific lectures on psychology, to bedtime stories for the- kiddies — grand opera to jazz— one gets what one likes the best. By the slightest turn of a dial, we turn in to the broad- caster that most interests us, for radio - service and .amusement, today, is almost unlimited. Radio keeps a home together. It makes one's home the center of the universe. A Christmas Thought for National Radio Week THOUSANDS of reader* of RADIO WORLD will be purchasing new radio sets or replenishing their present equipment between this date and Christmas Day.. Why not share your joy of ownership by taking advantage of the special opportunity offered during National Radio Week and set aside one or two evenings during that week for the entertainment of less fortunate friends by letting them listen-in on your set? National Radio Week is from December 23 to December 30, inclusive. Each reader of RADIO WORLD can help radio along its merry and interesting way by getting up a Radio Party and, by so doing, increase the ever-growing army of radio enthusiasts. Remember, the National Radio Week dates are from December 23 to December- 30. Make your plans in advance and then write and tell us, briefly, what you have '"radio't^nk country*.1" th°" ^' °' n,emo'»b,• » W»to«T

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RADIO WORLD 7 Radio, This Christmas of 1922 A YEAR ago, when radio had not progressed to It* praaont high placo Radio baa boeomo aocnethlng mora than a fad. It is now ana of tho hi tha world of adonca and entertainment, tho gueeHon asked by every- world'* graataat natural utilities. Nations depend upon It far anils-fa tan- body Interested waai "What will tha ChrUtmaa of 1MZ brine forth? mant and tha Interchange of diplomatic, scientific and boom ess meeaagee. Tho propm reeults of raaaonablo dwvelopniaut or merely tha chaoa that Armies and navies, whether they continue to exist In a m snaring or a ao oftaa fattowa tnaaandoua Intaraat in something maw 7" protacttvo measure, find radio an adjunct of marrakma power aad useful- Wei, tha now holiday aaaaon la bar* and with it oanwa tho anawar. —~- Gr~t »«■*•» problam. of transmission ara borne »oNod through baa Justified itself both as a adanea and a* tha amuaaaaant of asfanona. Groat chanfoa bar* coma, Scientists Kara given of thair boat in add*** definite expression to tho potantUlWaa of radio. Waffle formarly than waa confuaion as to cartain tachnieal aaaies thara baa coma tho solu- tion of many difficulties. Whara tana of this wondarful agency. In fact, avory activity of Ufa, whathar EACE on an earth apannod by the radio waves carrying tha message * of good will from man to man. Let Us Rejoice and Be Glad By Lee de Forest Inventor of Many Important Radio Devices us rejoice and be giad hi thla idea of a Radio Chriatmaa! Not ' for thla year but for all years to cornel Indeed, why not? Not ar dm immediate Joy that it win bring to tho heart of the incH- aoy or girL Not alone for tho further encouragement it will bring man who ara giving time and thought to tho development of the itself; but for the graataat of all reasons: namely, that with radio art we of the industry are inatall'ng tho moot marvelous of all ET to tha instruments for spreading the tiding ■ toward men. of peace on earth and good will Radio Has Come to Stay By H. Gernsback Editor "Radio News" THERE have been many Christmas celebrations in which radio baa piayod a part, during tho past ten or twelve years, but this is really tha first Radio Christmas. It is the first time that radio has penetrated into the homes of a very great proportion of the population of the United States, and for that reason It should be celebrated by every one interested in radio with this in mind. Radio baa come to stay, and the writer trusts that it wlU be the means of bringing good will and cheer to connected with radio. Broadcasting, a Public Utility By Jack Binns Radio Editor, "The Tribune," New York City Jg ROADCASTINC ia rapidly assuming tho status of a public utility. Any which wUl foster its development along right lines la a con- tribution to human progress. The Idea back of National Radio Week constitutes such a plan and, I hope, will materially aid in 'placing broad- casting where it' rightfully belongs in the public esteem. Awestruck at the Future By Elmer E. Bucher Manager, Sales Department, Radio Corporation of America I F radio broadcasting accomplished nothing else, it would be won worth * while for the splendid entertainment and contact with the outer world which It bring* to tho isolated community or Individual and to the sick and the feeble. But already baa thla great facility demonstrated a hundred worthy uses, from tho amusement of tots fas their nurseries to the dis- semination of important information to business man and farmers the country over. With such impetus as radio broadcasting baa gathered in lta abort existence, even wo in the Industry are awestruck at tha future possibilities of thla institution in which wo ara ' A Mighty "Yes," the Answer By Charles E. Fay Tufts College, Boston, Massachusetts OES not the marvelous invention of radio offer the best "Peace, Digitized by Google

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8 RADIO WORLD The Aerial Press of America By IV ashington R. Service PERHAPS, at last, there is something new under the sun. Whoever thought of an aerial newspaper before a few pioneer men- tors of public opinion began broad- casting their news items that all who "listened in" might hear — free? Among 582 radio stations broadcast- ing in the United States, today, there are 83 representing publications — most of them daily newspapers. Nine of these etherial news sheets are super, or Class B, stations especially licensed to broadcast on a 400-meter wave. All told, these news broadcasts of the air reach millions who do not sub- scribe to the publications but who are most enthusiastic aerial "hearers" none the less loyal to their favorite papers because they are unknown to the edi- tors. There is an "Aerial Press of America" even though there are no aerial subscription lists and no adver- tising accounts. It is certainly something new, this broadcasting of the news and sports of the world, gratis. It is a service highly valued by the hearers. Many predict that it has come to stay. Some Canadian newspapers have also taken up the scheme of news broadcasting, as well as publications in Porto Rico and Hawaii. George Schubel, secretary of the Radio Broadcasting Society of America, a publisher, has made a study of aerial news distributing, with the result that he advocates the broadcast- ing of news matter by publishers. Paralleling the printed news, he claims, broadcasted news serves both national and local fields and provides for a versatility of free expression of public opinion. Radio can be used in the gathering of news as well as in its dissemination, especially in country districts, and tends to broaden the scope and circulation of a newspaper. There are several known instances where radio carried daily news reports when other lines of communication failed, and, in some instances, amateurs aided. An SOS story has been covered by wireless and aid rendered by means of radio as well on land as at sea. Instances where the wires and regular channels were beaten are recorded. Government weather, crop and market reports are now carried by radio in advance of press releases. The only way by which a newspaper can hope to compete is through the same medium. "Why give away material?" may be asked. This is answered by citing the case of the Boston "American's" ex- periments in broadcasting bulletins from its news before they were printed. The news is transmitted from WGI, The Latest Vamp ! (Cartoon by Lawrence B. Hinckley) Med ford Hillside, and the service to thousands is reported to have brought most valuable publicity to the Boston sheet. All who listen in to brief news items want to know more of the de- tails and, naturally, purchase a copy of the "mother" sheet as soon as it is available. Out of over eighty papers licensed to broadcast, only about half a dozen have stopped this service. A few have combined with other or- ganizations in the use of a single broadcasting-station. The following United States newspaper! operate broadcasting services: KDYL — "Telegram," Salt Lake City, Utah. KDYR-"Star-News," Pasadena, Call- fornia. KDYS — "Tribune," Great Falls, Montana. KDYU — "Herald," Klamath Falls, Oregon. KDYX — "Star-Bulletin," Honolulu, Ha- waii. KDZA — "Daily Star," Tucson, Arizona. KDZH-"Evening Herald," Fresno, Cali- fornia. KDZR — Bellingham Publishing Company, Bellingham, Washington. KFAC — "Daily Press," Glendale, Cali- fornia. KGW— Oregonian Publishing Company, Portland, Oregon. KLX— "The Tribune," Oakland, Cali- fornia. KSD— "Post-Dispatch," St. Louis. KUO— "The Examiner," San Francisco, California. KWH— "The Examiner," Los Angeles, California. KXD — "The Herald," Modesto. California. KZN— "Salt Lake Deseret News," Salt Lake City, Utah. WAAF— Chicago Daily Drovers Journal, Chicago. WAAL — "Tribune," Minneapolis. WBAD— "Journal," Minneapolis. WB AD — "Star - Telegram," Fort Worth, WBAU — "The Republican," Hamilton, Ohio. WCAB — "The News," Newburgh, New York. WCAG— "The States," New Orleans, Louisiana. WCAW— "The Herald," Quincy, Massa- chusetts. WCX— "Free Press," Detroit, Michigan. W DAE— "The Times," Tampa, Florida W DA F— "Kansas City Star," Kansas City, Missouri. WDAK— "The Courant," Hartford, Con- necticut. WDAL - "Times-Union," Jacksonville. Florida. WDAV— "Muskogee Daily Phoenix," Phoenix, Arizona. WEAR — "Baltimore American," Balti- more. Maryland. WFL— "the Chronicle," Houston, Texas. WFAM— "The Times," St. Cloud, Min- neapolis. VVFAT — "Sioux Falls Daily," Sioux Falls, South Dakota. W FA W— "Daily Metropolis," Miami. Florida. WGAR— "Fort Smith American," Fort Smith. Arkansas. WGAZ — "The Tribune," South Bend Indiana. (Continued on the following page)

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RADIO WORLD How to Prepare Hard Sheet- Rubber for Your Radio Apparatus By JV. S. Standiford THE experimenter in all kinds of electrical apparatus finds it necessary to cut hard sheet-rub- ber into round discs for making Wims- hurst machines, or for parts of wire- less-telegraph and telephone sets now used extensively. The amateur radio- phone-maker uses wood for his panels and large diameter cardboard tubes for his vario-coupler, tuner and other parts. While wood may be used for a panel, it is not nearly as effective as hard rubber. Factory-made appliances are constructed of the latter or of an in- sulator equally as good. Cardboard is a fragile substance and does not give continuous service as a vario-coupler. On account of hard rubber, in its dry state, being difficult to cut and bend into cylinders for radio parts, ama- teurs use wood and cardboard. The writer, after some experimenting, found an easy way to cut and bend hard sheet-rubber 5/16 inch thick. Mark an outline on the place to be (Continued from preceding page) WGF — "Register and Tribune," Des Moines, Iowa. WHN— "Ridgewood Times," Ridgewood, Long Island, New York. WOZ — "The Palladium," Richmond, Indiana. WPA— "The Record," Forth Worth, Texas. WSB— "The Journal," Atlanta, Georgia. WWB— "Daily News," Canton, Ohio. WWJ— "The News," Detroit, Michigan. KFAP — "Standard," Butte, Montana. WHAS — "Courier Journal and Times," Louisville, Kentucky. WHAT— "Democrat," Yale, Oklahoma. WHAY— "The Press," Huntington, In- diana. v WIAC— "The Tribune," Galveston, Texas. WIAK — Journal-Stockmen Company, Omaha, Nebraska. WIAN— "Chronicle . and News," Allen- town, Pennsylvania. WIAQ— "The Chronicle," Marion, Indi- ana. ; | WIAS— "The Hawkeye," Burlington, Iowa. WJAF— "The Press," Munsey, Indiana. WJAG— "Daily News," Norfolk, Ne- braska. WKAA — "Republican-Times," Cedar Rapids, Michigan. WKAC— "The Star," Lincoln, Nebraska. WJAN— "Peoria Star," Peoria, Illinois. WJAQ — Capper Publications, Topeka, Kansas. WKAK — "Okfuskee County News," Oke- mah, Oklahoma. WKAM— "Daily Tribune," Hastings, Ne- braska. WKAT— "Morning Times," Frankfort, Indiana. WMAJ— -"Kansas Drovers Telegram," Kansas, Missouri. WMAQ — "Daily News," Chicago. WNAB— "Park City Daily News," Boiling Green, Kentucky. WRAU— "Daily News," Amarillo, Texas. KFBS — "Chronicle News," Trinidad, Colorado. WGM— "Constitution," Atlanta, Georgia. WNAS— "The Statesman," Austin, Texas. WHAL— "Capitol News," Lansing, Michi- gan. KHJ— "Times-Mirror," Los Angeles, Cali- fornia. KYI— "Bakersfield-Californian," Bakers- field. California. WFAA— "Dallas News." Dallas, Texas. KVQ— "The Bee," Sacramento, California. There are students of the problem who believe that press broadcasting sta- tions should handle all news, since the news is really owned by members of the press and is received, first, by them; besides which, the publishers know how to handle the news better than any other agency. Newspapers, usually in the lead of progressive de- velopments, are apt to find it neces- sary to follow the lead of the aerial pioneers and, in future, carry radio- news bulletins for their clients. Radio is a household contact with the world. Of the newspaper broadcasters, nine have secured the Class B license per- mitting them to broadcast on 400- meter wave; they follow: Atlanta "Journal," Atlanta "Constitution," Dallas "News," Detroit "News," De- troit "Free Press," St. Louis "Post- Dispatch," Kansas City "Star," Fort Worth "Star-Telegram," and Los Angeles "Times-Mirror." The Seattle "Post Intelligencer" now uses the broadcasting station KFC; the Philadelphia "Record" broadcasts through WCAU; "The Ensenada News," Yauco, Porto Rico, uses WGAD; the Indianapolis "Star's" news is released through WOH; the Tacoma "Times" co-operates with KMO; the "Oklahoman" "speaks" its news over station WKY; the Boston "American" uses WGI, and the Mem- phis "News-Scimitar" announces over WPO. In Canada, two news broad- casters are the Toronto "Daily Star," operating CFCA, and the Winnipeg "Tribune," CJNC. Among other daily papers said to be planning to use news broadcasting are "The Courier," Grant's Pass, Oregon ; "The Gazette," Billings, Montana; "Raleigh Register," Beckley, West Virginia; "Daily Telegram," Adrian, Michigan; "News Herald," Litchfield, Illinois, and the "Pilot," San Pedro, California. cut, using a scriber or knife. Then plunge the sheet into very hot water until it is of the pliability of leather. Cut along the mark with scissors, or tinsmiths snips, according to the thick- ness of the material. As it becomes cooler it will be more difficult to cut. If any further cutting is to be done, place the sheet-rubber in hot water again and continue as I have described. Next place a sheet of glass on a news- paper on your work-table. Dip the rubber in hot water again, place it on the glass, put another sheet of glass on top of the rubber and weight it down. When cold, the piece will be found to be straight, the cutting hav- ing thrown it out of shape. To bend the hard sheet-rubber into cylinders for tuning coils and other parts, make a wooden mandrel of the desired diameter, measure its surface with a tape measure, and cut the ma- terial the desired length. Heat the rubber in hot water. Place two wooden blocks on a smooth surface sufficiently far apart to be even 'with the edges of the rubber to be bent. Put the hot sheet in position on the blocks and press down the mandrel on its center, gradually curling it into cylindrical shape to fit the mandrel. With thick plates, reheating them several times may be necessary to pro- duce the desired shape. When cold, fill the crack between the two edges with automobile-tire cement There is a rubber putty-composition for mend- ing tire cuts which is excellent for joining edges. It is best to tie the cylinder tight, with string, until either the cement, or putty, has set. Polishing hard rubber is a poser for electrical experimenters, as they do not understand how to make the edges of the sheets as smooth as their sides. Therefore, they generally smooth the. edges with a file and let it go at that. This mars the appearance of the in- struments. By the following process an even polish will result: Fasten a piece of fine-grained sandpaper to the top of your work-table and run the piece of rubber across the sandpaper in a series of smooth strokes, taking care to keep the grain straight. Con- tinue this operation on a second sheet of the finest sandpaper that can be ob- tained. Wipe off all dust and give the edge a coat of shellac in order to fill the pores. When dry, rub with a piece of felt tacked to a wooden block— the felt to be dampened with oil and FF grade of powdered pumice-stone as an abrasive. Digitized by Google

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RADIO WORLD The Radio Primer *»*&.f°?* Fifurc 1— Showm* tha battery whara chemical action tahaa place to praduca •Uctridty. (Ht9HT»t) -JSz For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin ciples Fully and Tersely Explained By Lynn Brooks y fOW are electrons moved about? § M The chemical action of elec- M M trons we have described, al- though it is not called by that name. You light a cigarette — chemical action changes the tobacco into smoke. An apple decays — chemical action has caused this change. Light a fire— chem- ical action creates the heat. So it has been found that, under certain conditions, chemical action will feed electrons on one hand and destroy them on the other. * * * How can chemical action be started t Fill a glass jar with an acid. Put into this acid a piece of copper and a piece of zinc, allowing both cop- per and zinc to stick out of the acid. We have made then what is called a voltaic cell. Usually we just call it a cell. A group of cells together is called a battery. The accom- panying sketch shows what we have done. Chemical action will re- move electrons from the copper and give electrons to the zinc, so that B has more than the usual number of electrons and A has less than its usual number. B is called the nega- tive terminal; A the positive ter- minal. Connect A and B by a wire and the electrons will flow through a wire from B to A. They will flow continuously because the chemical action keeps the zinc supplied with them. Connect the two terminals by a wire and show the direction in which the electrons flow and the direction of the current. * * * Now that we have electrons flowing, what have we accomplished? We have produced all the condi- tions necessary for an electric cur- rent. An electric current will result if we keep a voltage between two terminals, as with the voltaic cell, and connect these terminals by a conductor. To study electricity further, we must study the electric current. * * * What makes a current t A flow of electrons makes a cur- rent. If we measure the number of electrons flowing, we must state a definite time in which to cpunt them. The defin"*" time is a second. Then, also, confine our Fi«ura J— Showing how tha electron* traval from tha navativa to tha poaitlva tarminala. measurement to one place in the path of electrons so that we measure current by counting the number of electrons which pass a given point in a second of time. * * * What is unity of measurement t The unit of measurement of electric current is the ampere, just as the measurement of weight is the pound. We say that an object weighs 13 pounds. In the same ra- tio, we say that a wire carries a cur- rent of 15 amperes. Thus you see an ampere means a definite number of electrons passing a point in a sec- ond of time. There is an instrument known as an ammeter. It is used to measure the number of amperes. In electricity you will find the word "meter" affixed to various words. * * * How can we secure as many amperes as we want? In other words, how can we control the number of electrons passing a given point in a second t In Figure 2, electrons are shown trying to journey from the nega- tive to the positive terminal. They act like a crowd of people trying to rush out of a building the en- trance to which is blocked. By Charles H. Plath ONE thing we must gfuard against in radio-receiving sets is dust and dampness. The set should be kept, preferably, in a dry room, otherwise moisture will gather in the interior of the works and, probably, form contacts which may lead to the short circuit of the set or give leakage of current. The B batteries should be kept in a dry place, preferably a box, other- wise they will get weak and become "dead." A handy thing around a station is a small long-handled brush. This is used to keep the dust away from switches and parts. Care should be taken to keep the switches and condenser terminals clean, also any other place where dust may col- lect. It would be a good scheme to clean and dust the set once an even- ing. This would prevent the dust from collecting in quantity, thereby preventing any leakage to the set. Care and attention should be given to the set as it is delicate. If this is accomplished the set will function. * * * ANTENNA insulators should be kept in good condition and wiped off occasionally ; because they collect a certain amount of dirt and carbon, especially when near any smoke- stacks. A film of carbon or dirt over the surface of the antenna in- sulator will cause leakage and an improperly poor-range set will be the answer. Sometimes other de- velopments happen in the aerial, so it is best to be certain that the aerial is well insulated from the lead-in to the set. The lead-in may be touching some metal near the house, or in the room where it connects with the instruments. * * * WHEN a dry cell is run down a very good way to get some extra life out of the battery is to work as follows : Remove the wrap- per from the cell and place it in a can 5 or 6 inches high and about an inch wider in diameter than the cell. Fill the can with vinegar and a lit- tle salt. The salt should be shaken i into the can and stirred well. Let this mixture stand overnight. Next } morning, on inspecting the old bat- tery, you will find that it has as much pep as if it were a new one. The battery should be left in this solution until it becomes exhausted. It has given many hours of life be- yond the period when it was thought "dead" by the amateur. This is quite an experiment, and every ra- dioman who uses dry cells should give it a trial and watch the results. The scheme comes in handy when in a pinch for some voltage. Digitized by Google

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RADJO WORLD 1! Some of the Leading Daily-Newspaper Radio Editors of the United States (Roanta* tram laft to right) Top Row-Raymond Fraud* Yatoa, "Tfca Mad." N«w Yorii CHy; 5. F. Owaa, Tha Oil— to J— mat." Atlanta, Oaar- fia; Evarott A. RudlocT, "Aabury Park Praaa," A«au Path, Naw Jaraay. Sac— J Raw-O. C. Condon, Jr, "Dm Atlaata CanrttatJoa," Atlaata, Ciargto; Frank J. Mala*. Tha Caaatta," Sen— art* ty. Naw Yarfc; Ray— a C. E. Fryda, "Tha Enqtarar," Buffalo, Naw York; E. 1_ Braffdan, "Tha Cloba," Naw Yarit CHy; Jahn H, Oymar -Jackaaavflla J ■■ail." JackaaanrfDa, Florida. Directly undar Mr. dyasar'a ahato«Taah la< ■ Btaaa, Tha Trinnaa," Naw Yark aty. Battaan Raw Ckarlaa D. Kalkty, editor and aaparriaor Datralt "Nawa" Brondcaatma Dapartaaaat, Datrait, Michigan; Jaka E. Haraaa*. -Naw Canaan Ad- Tarbaar," Naw Canaan, Connactieut; Arthur F. Hardwick, Tha RauahlU an." Springnald, Ma***chaartta; Jack Taraar, Tha Aga-rUrald," BlnaJnakinj. Alabama; Mia* Marlon Stowa, "Hartford Tub**," Hartford. Coanacticat.

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RADIO WORLD Receiving and Denoting Direction of Radio Signals with a Coil of Wire By S. R. Winters fin. photograph of a "loop," or "coil," antenna, or vertical conductor electricity. The antenna to ehown In place with a complete receiving- L When supported by a six-stags amplifier, signal* are received from WHEN one or more turns of wire form a square, or rectangular frame it constitutes a coil. A rope, not in use, when forming a series of rings, or a snake gathering itself preparatory to spring- ing toward an object, are common illustrations of a coil. Speaking in» electrical terms, however, copper wire wound around a wooden frame — the strands of which wire are spaced one-half of an inch, or one inch, apart — constitutes an antenna for the reception of wire- less communications. The "coil," or "loop," antenna and the "overhead," or vertical conductor of electricity are well-nigh household terms emblazoned on the crest of popularity of radiotelephone broadcasting. Experiment* That Lead to Success A coil of wire as an electrical inductance, other than being the most compact form of antenna, is as versa- tile as the proverbial Jack-of-all-trades. It may be enclosed completely in a suit-case — or, when rigged-up in a wilderness for the reception of wireless signals, it may determine the direction of the transmitting station from which the communications are coming in. The photograph illustrates a portable radio-direction finder employed by the United States. The coil of wire, form- ing an antenna, is mounted on a vertical axis on which the frame supporting the strands of wire may revolve freely. Meanwhile, as the coil is rotated about its axis, a curve is plotted indicating the variations in the strength of the electric current received for the electro- magnetic wave approaching from a particular direc- tion. The coil of wire, when employed in this capacity, may be dubbed correctly a direction finder or radio com- pass. The electron-tube amplifier, with its score of other triumphs, has been a boon in the use of coils of wire as antennae. In the absence of substantial amplifica- tion of the feeble electric-current received in the coil antenna, the few turns of wire on a square wooden frame would be as powerless to produce audible sig- nals as a pyramid. The Radiocommunication Section of the Bureau of Standards, United States Department of Commerce, has conducted extensive experiments with strands of wire wound about a frame as an an- tenna, and recommends the use of six stages of ampli- fication for satisfactory results. However, with two stages of audio- frequency amplification, wireless sig- nals may be received from nearby stations. Versatility of the Coil Antenna If supported by six stages of amplifications, a coil antenna located in Washington, D. C, may record wire- less signals from the high-power radiotelegraph sta- tions in France and Germany: An exceptional instance of the capacity of a coil antenna is noted where all the big European stations were received in France by use of a frame containing 200 turns of wire, only eighteen centimeters square. The radiotelegraph signals ema- nating from the high-power station of the United States Navy Department at Annapolis or Greenbury Point, Maryland, have been recorded in Paris, France, by the use of a coil only ten inches in diameter. The versatility of the coil antenna is suggested by the development of a complete radiotelephone receiving set in an ordinary suit-case with the form of antenna snug- ly encased in the covers of the traveling bag. It was developed by the Bureau of Standards, the coil an- tenna and half a dozen audion bulbs encased in a con- tainer only 7 by 11 by 18 inches in dimensions. The coil antenna, other than serving as a direction- finder afield, lends itself to use in locating the direc- tion of wireless signals when installed on seafaring vessels. A system of radio direction-finding for navi- gation purposes in fog and thick weather has been developed by F. A. Kolster, formerly in the service of the federal government, and F. W. Dunmore, of the Bureau of Standards. The striking directional char- acteristics of the coil antenna suggest its fitting appli- cation on radio-equipped airplanes, especially when flying is to be done in foggy weather or at nig^ht. Such a form of antenna is of a discriminating caliber. Its directional tendencies are such that strong signals may be recorded from a particular point of the compass and feeble wireless signals from other directions. Thus, by capitalizing the directional qualities of the coil an- tenna, interference from transmitting stations whose offerings are not desired, may be curtailed. Radio amateurs have reported their experiences re- ceiving signals by use of a sensitive receiving-set even when their antennae were altogether discontinued. This phenonenon is explained by the fact that the wiring of the radiotelephone receiving outfit assumed the form of a coil antenna. Digitized by Google

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RADIO WORLD 1 New Chief of Radio Corporation Chosen from United States Army ■ n 9* (Courtery of Radio Corporation of America) • Major-General John C. Harbord, U. S. A. ** AJOR - GEN ERAL JOHN C. HARBORD, on* of th« distinguished officers of the Unltad States Army, ranking only below General ™ PmUnf, aa Deputy Chief of Staff, will retire, on December 2t, to become president of the Radio Corporation of America. The Secretary of War approved hie application for retirement. Both Mr. Weeks and General Perching stated publicly that General Harbord had served in the Army in a highly distinguished and loyal manner, and that his unusual experience aa an organizer and executive would Insure his success in the business world. The post for which General Harbord has been chosen la regarded of vital importance to the Government aa well as the public, since the Radio Corporation of America was formed at the suggestion of representatives of the United States Navy in order that powerful world-wide radio communication, free from foreign domination, might be built up. Digitized by Google

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14 RADIO WORLD Radiograms The Latest Christmas Radio News Briefly Told for the Growing Army of Radio Fans THE plan, recently adopted by the police of the country of broadcasting fingerprints of captured criminals to ascer- tain if they are wanted elsewhere, resulted in the return to New York from Los Angeles of Harold J. Burns, of New York City. Burns, who is said to have used the alias "Darcey," is wanted here in connection with an alleged homicide and two burglaries. He jumped a bail bond of $12,500 to avoid standing trial on the former charge. The broadcasting of his finger- prints and his apprehension chalk up a new record for radio as a crime deterrent. * * * An epidemic of influenza occurred among the officers and crow of the American steamer, "President Roosevelt." The chief officer of the vessel and the purser were among those ill. Supplies of brandy were ordered by radio for the invalids. These were sent on board on the arrival of the steamer at Plymouth and quickly administered. The Volstead act may mean one thing, but radio is ever ready in time of need not only to uphold American liberty, but to protect the sick and forestall epidemics. * * * Reports from Croydon, Surrey, England, that a radio engineer had heard parts of the musical concert broadcast from WJZ, of the Westinghouse Electric Company, proved the success of an experiment they were making in increased power. J. H. For the First Time Santa Claus is Delayed (Cartoon by Harry B. Stilman) Santa Claus:— How do they expect ma to maka my rounds with this radio Ridley, of Croydon, said he heard the WJZ call and then the strains of a familiar overture. He stated the time was 1.15 o'clock Monday morning, November 27 (8.15 o'clock Sunday night, New York time). Westinghouse radio engineers said they had doubled the power of the broadcasting plant two weeks ago and that on Sunday night atmospheric conditions were at best. * * ♦ A system of pilotless airplane control in France has passed a two-day test satisfactorily, according to experts who super- vised the trials with a 300 horse-power passenger carrying government biplane that flew over Etampes aviation field. The plane, going aloft with no one aboard, responded to control by radio from the ground, performed all the customary evolu- tions, and then landed safely. During the tests the machine was frequently lost from sight in haze and clouds, but it was always under radio control. * * * Construction of a huge radio transmitting and receiving station in Miami, Florida, for handling South American, Central American and West Indian business to be relayed direct to New York, will be undertaken by the Tropical Radio Telegraph Company, of Boston, a subsidiary of the United Fruit Com- pany, it was announced by George S. Davis, general manager of the radio company. The towers of the sending station will be 437 feet high, higher than any in America, except those at the Arlington Naval Station. * * * The Capitol Theatre, New York, musical program, broadcast direct from the theatre, proved another big radio success. This radio-engineering feat, by the American Telephone & Telegraph Company, was accomplished by means of a highly sensitized microphone suspended twenty feet ' from the roof and thirty feet from the stage. The sounds of the music were caught by the amplifiers and then carried over specially equalized telephone wires to station WEAF and broadcast from there. This is the first time in radio and musical history that symphonic music by a large orchestra was broadcast direct from the theatre during a performance. It is estimated that over 600,000 radio sets caught the concert, reaching a probable audience of over a million persons. Telegrams and letters from stations reporting the success of the concert were received from points in Ohio, Michigan, Minnesota, Nebraska, Ontario, Toronto, the New England States, Kentucky, Virginia, Georgia, and one thousand miles out at sea. * * * The great improvement in the power, clarity, and brilliancy of WJZ, Newark, New Jersey, has startled many who have been accustomed to receive this station at the full power of their sets. Listeners in have been compelled to reduce their amplification materially to prevent the signals from being in- tolerably loud. The explanation of this improvement is that WJZ has a new transmitter. Though the old one was generally regarded as one of the finest in the country, recent develop- ments by the Westinghouse engineers rendered it obsolete, and that it was removed and a new one, up to date in every respect, installed in its place. This new transmitter is rated at double the power of its predecessor. It has 1,000 watts and is greatly superior in the details of its transmitting, modulating, and generating system. It is about three times more effective than the old transmitter. While listeners with electron-tube receivers all over the country have been quick to notice the change, it has been especially pleasing to local owners of either crystal detectors or loud speakers, who are now able to get highly satisfactory results from their instruments. * * * Millions have enjoyed the Chicago operas, broadcast by radio. r j audience in and around New York listened to the music of Aida," played in Chicago and broadcast on the 400-meter wave length of station KYW. The voice of Rosa Raisa was heard as clearly in New York as in the Middle West. Since the opening of Chicago's opera season the radio audiences have heard Carmen," with Mary Garden singing the leading role, La Boheme" and "Parsifal." Two operas will be broadcast each week from 8 p. m. to 11 p. m., central standard time. Be a National Radio Week Booster Digitized by Google

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RADIO WORLD 15 Radio and the Woman Crystal D. Tector Sends a Goodly Radio Measure of Christmas Cheer and Some Pertinent Advice DURING the past few weeks, I have received an unusual number of technical questions to answer — and, singular as it may seem, all but a very few sent to me by men. If I should attempt to answer so many questions in my de- partment, I wouldn't have space for half the necessary replies; so I have turned over all these communications to the technical editor of Radio 'World and he will answer them in the regular department, "Answers to Readers," from week to week. I deeply appreciate the confidence that so many men place in my ability to help them; but, and I am sure they will agree with me, I have so much else to write about that devoting my alloted space to answers of a technical nature would deprive me of my customary weekly chatter. * * * THIS is the Christmas Number of Radio World— a number that goes forth to all of you with a hearty message of gladness and cheer. In a way, it is the forerunner of the Na- tional Radio Week Number which will be published the week before Christmas — dated December 23, to be exact— as on that evening the festivities that will mark the celebration of the first big week set aside for radio and the first Radio Christmas, will begin. I believe that every radioist at heart will do something during this week to increase the interest in radio— to bring at least one new fan into the fold. While the great army of radioists is growing faster than the most sanguine of us an- ticipated, there are millions who, as yet, are uninitiated. And the larger the radio family, the more healthy it will be. The more people enrolled as radio enthusiasts, the faster will per- fection in radio development be attained. We pioneers are look- ing to a day when radio will be declared the most vital, neces- sary, and important family element in this country. * * * T SUPPOSE that I have written over a hundred letters to X as many women, in the past week, giving all sorts of in- formation regarding the formation of committees, menus for suppers, suggestions for window decorating, banners, signs and what not. I hustled these answers by post because by the time the replies would reach you through this page, the infor- mation would be too late for practical use. From the letters received, I feel that the spirit of radio week has become deep- rooted in the heart of the feminine radioist. I felt all along th.a,t .we women would do our part. And, why not? Radio will interest women just as keenly as it will interest men. I was not at all surprised at the many letters that I have received from mothers whose sons are begging them for sets for Christmas. * * * *"pHESE mothers have beseiged me with all sorts of queries . as to what is the best set to buy, what is needed to com- prise a set, how will they know that the apparatus will work after it has been purchased— and all that sort of thing. Now, you. cannot blame a mother when her young hopeful demands such an outlay for Christmas. She wants to know that her money will not be wasted; she wants to be sure that she is going to be advised correctly. It has been the greatest pleasure to me to devote my time to these mothers— and it will be a greater pleasure if they will write me when their boys' sets are in operation. If any mistakes occur, I will feel duty bound to help set them righ.t. * * * "VITIEN my little boy came to me the other day," writes 4. .;..on.e deaf mother in Texas, "and told me, so plaintively, that this is to be 'a radio Christmas,' and he didn't want to be behind the times, I simply couldn't refuse him. We live far from a town of any size — and I must ask you to help me. Tell me what to do and what to buy." Only a stony-hearted woman could refuse an appeal like that — and I am not, My heart goes out to the little ones— especially at Christmas. * * * DO you know that one of the most wonderful bits of broad- casting was the services of the St. Thomas Church, Fifth avenue, several Sundays ago, and so well described by Peter Gray in Radio World. I had invited a score of neighbors to my house to hear it. The solemnity of it all, the sacred music, the sermon by Dr. Stires, possessed all the wonderful potentiality and had more effect, if I do say it, than if we bad been seated in the great edifice. There was Friend Husband, who hasn't seen the inside of a church since — oh, I'm ashamed to tell — and others equally as guilty, listening in with all the eager- ness and interest of the most devoted parishioners. One man who hadn't heard a sermon preached since he was a little boy, remarked that Dr. Stires's words filled him with real in- spiration. Others were equally as impressed. It was a soul- satisfying, impressive service. And, let me add, radio is going to bring about the long-looked for return to religious devotion. I don't say it may, I repeat that it will. * * * r*OR many years, and the ministers have admitted it from time to time, the great majority of us have not taken kindly to religion and we have not attended divine worship as did our forebears. Radio will bring religion to the masses as no other element can or will. Some have scoffed that it is not a thing to be broadcast, that nobody wants to hear a sermon. Well, I can truthfully state here that my friends who have asked when they may hear another St. Thomas service will more than fill my radio-reception room. Dr. Stires has done a big thing. He and other ministers who have made the microphone as important as any other phase of divine worship deserve our thanks. * * * DERHAPS The Saviour himself might have foreseen in . h,s&rea.t1 human vision— just this present-day occurrence when he said that he could destroy the temple and rebuild it in three days. Perhaps He meant that one did not Have to go to church to hear the word of God. Perhaps He foresaw that this mighty and mysterious power of the air would carry His thoughts and teachings to all parts of the earth even unto the remotest hamlet and the humblest home. Don't miss hear- ing such a service as I have described oh, ye of little faith for some mysterious element that surrounds it aU will awaken in you the belief that a Greater Power is giving unto all man- kind the things that mankind is inclined to receive with clouded vision. * * * A ND so it is fitting at this time of the year that we realize 1 \ » j*st^ne. great *°?d to the credit of radio. This is the first Radio Christmas. Radio will spread the gospel of Peace and Good Will this Christmas as it has never Been spread be- fore^-and, in years to come, we will look for our Christmas service by radio just as we will look for every other gladsome feature of this happy time. So, here's to a Happy, Joyous, Radio Christmas for \922. May we have a bigger one in 1923! —Crystal D. Tector. DONT place your batter? on chare* without making- th« correct polarity connection*. Don't chart* your battery without knowing til* density of th* acid. Don't allow th* storage battery to cat low, do* to Deflect of attention. Don't Ut th* water rot low in your battery. AJway* add die tilled water from time to time. Don't fill your batteries on carp**. Th* add will aat hole* in It. Radio Don'ts Don't tight your tube* up to brilliancy, not It U Don't try to look for all-war* radio- frequency transformer*. There are none. Don't try to us* WD-U vacuum tube* for Don't try to us* WD-U tube* for ation. They will not hold out WUI *J*Bv n 1.11*3*1 in IT., Don', try to hear dmd, when th. polarity Jn^T'LS^" "Y£ STt? ? ^"SZ of th* B battery are wronf. *r*nc*. oupler J%*>'\ I,°"tuf «"> primary of your varlo- without loading th* secondary. Don't expect to know how to tun* _ , Mv* receiver th* first time you get one. Don't forget that with a two-variometer type receiver the wave length cannot be hwTrrer N» meters. ZSM mttera is not obtainable?^ .ESEj SZJ?J"*r >onr^»steac* station* with a «T to employ lK-voH tub** in a radio. J*»Wjency or supsrr*c*a*ratlv* set. They Digitized by Google

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1ft RADIO WORLD Radio's First Big O'er with Gl (C. Kadel & Herbert) (Above) One impor- tant element of ■ vacuum tube receiv- ing act la the stor- age battery. The only teat one can give thla battery to inaure life la the hydrometer teat. Thla inatrumcnt may be purchased for a reasonable sum. It comprise* a rubber bulb at one end. The end of the tube is placed in the liquid and inaide the bat- tery containing the (Left) Thla is KHJ, "The Times." Los Angeles, California, in opera- tion. Input panel, transmitter panel, power panel, and reading room from left to right. KHJ, on SOO watts, haa done a radio in the Southweat since November 1. One can almost see the are "on the job" In the room with correct broadcast acoustics, graph ahowa only the instrument (Left) That radio broadcasting la uaeful aa well aa entertaining la" proved by Miaa Emily Exner, who keeps a typewritten record of come to her by radio. She is an ardent radio fan and spent so much time experimenting with her radio aet that her mother admonished her and told her it would be more to her credit If aha would "learn something about cooking instead of fooling around that old radio ma- chine." Then Miaa Exner, unknown to her mother, started to keep a record of the domestic science lectures, and, after a time, presented this valuable radiold information to her mother. Now ha thinks radio "just wonderful." (Right) William M. Priess, of Belmont, Massachusetts, for many years a resident of New York City, former Army officer, inventor of front-line radio communication sets and other apparatus used by both the Army and Navy during the World War, is fighting in the courts of Massachusetaa to retain control of hia inventions, for which patents are pending. The battle promises to become one of thai bitterest ever fought over radio patenta. The courts have just : an injunction restraining others from revealing the secret and processes of manufacture, from experimenting or otherwise < ing with certain inventions which Mr. Priesa claims. All the radio manufacturing corporations In the United States are pending the decision of this Digitized by Google

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RADIO WORLD 17 hristmas Brims i tisome News (Left) Tha (tone* battery wad to many radio fans who braak lata the cam* with rack apparatus. Dna to their six*, wclfht, and tha cara required, some ami must ha adopted to Imp thorn naar tha set yet where thoy may aaatty ba ranched. Tha accom- panying photograph shows a suitable shelf which makes a convenient place on which to keep A and B batteries. By following this plan, the batteries are out of sight sad the spill- In* of add and water on tha carpet is avoided. ition of America) vice-prasidant of tha Radio tha New York a tine to tha anoyance actual England. Franca, Germany, and Norway. (Right) Lord and Lady Mounthatten, extinguished British visitors. Inspecting the apparatus room of Station WEAK, of

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18 RADIO WORLD Latest Radio Patents RoylA. Weagant's New Device to Prevent Static No. 1,42*, 133. Patented August 15, 1S2Z. Pa tan taw ! Roy A. Weagant, New York, N. Y. ROY A. WEAGANT, one of the leading radioists of the United States, has been granted letters of patent on a device to prevent static in radiosignaling. Its pur- poses are best described m Mr. Weagant's own words, taken from the Patent Office specification. "I have found by experiment that atmos- pheric disturbances act as if propagated in a vertical direction only, whereas commercial radio signal waves travel horizontally, or have a large horizontal component of motion. Consequently static disturbances act simultaneously on the parts of a collector system which may be at the same height, while commercial radio waves act simul- taneously on those portions of a collector or antenna system which lie in a plane at right angles to the line of travel of the waves. "I have shown means whereby the effects of the atmospheric disturbances upon two parts of a collector or antenna system may be caused to neutralize each other, while the effects of the signal waves act cumula- tively on the receiving instrument,' owing For Rheostats No, 1,423 ,HS. Patented October 31, 1*22. Patentee: Joseph Cranz, Duluth, Mian. THIS invention relates more particularly to that type of rheostat used in con- nection with the smaller forms of electric motors and similar devices. It provides a structural formation and association of the rheostat parts whereby the resistance wire, or filament, having an extended or lengthy nature is effectively supported in a small Figure 1— Diagrammatic view of a receiving sta- tion showing one form of apparatus embodying Mr. Weaganf a invention. A divided collector of the general type is shown associated with re- ceiving and detecting apparatus. largely to the fact that the antenna or collector system comprises portions which are spaced apart along the line joining the receiving instruments with the source of the signal waves. "My present invention is an improvement providing a more simple arrangement in which the ends of a plurality of parts of an antenna or collector system are conductively connected in such manner as to greatly re- duce the effect of the atmospheric dis- turbances on the receiving instruments." Novel Battery Container No. 1,425,721. Patented August 15, 1*22. Patentee: Roy William Taylor, Chicago. ]V/f R. TAYLOR'S invention relates to A ■* improvements in battery containers. It provides a battery container adapted to house a plurality of dry cells and having means for connecting up such cells in either series or multiple in such a manner that The of the resistance member which is of an open skeleton construction and consists of a pair of flat plate metal sections of split-ring shape se- cured in properly separated relation by a series of connecting posts with the inner plate metal section attached to the Insulating bar or strip 4 to afford the sole supporting means for the and compact compass with a very efficient exposure to permit the escape of heat from such resistance wire during actual use ; also a simple and efficient construction and arrangement of parts whereby the frictional stress of the adjustable contact shoe upon the resistance winding during an adjusting operation can be materially relieved while electric contact is still maintained. Figure 1— End view. Figure 2— Section along the Una 2—2 of Figure L, any cell therein may be replaced at will. It provides, also, a device that can be used with a battery composed of ordinary flash- light cells, suitable for use in wireless tele- graph outfits and in apparatus used in elec- trotherapeutics. It is light in weight, com- pact, and adapted to be carried about, as in a small handbag. It is simple in con- struction and operation. Separation in Signaling No. 1,4»^M. Patented October SI, lsZZ. Patentee: Ralph Brown, East Orange, N. J. SIGNALING circuits in radio are the basis of this invention, letters of patent on which have been granted to Ralph Brown. Where it is desired to simultaneously send and receive in a radio system, as is necessary in the case of radiotelephony, it has been customary to separate the oppo- sitely directed transmission by employing some or all of the following principles: (a) separation by selectivity — that is, the The commute ting or switching operation may take place at three different points, (a) in the audio-frequency part of the system before modula- tion in the transmitting channel and after de- modulation in the receiving channel; (b) la the radio-frequency part of the system, and (c) la the circuits leading to the carrier frequency employment of different carriers for trans- mitting and receiving; (6) separation by balance — that is, the transmitting circuit is rendered at least partially conjugate with respect to the receiving circuit; (e) by geographically separating the transmitting and receiving antenna of a particular station, so that the sending energy from the trans- mitting antenna will produce a minimum effect upon the receiving antenna. For the most efficient operation all three of these principles should be employed simultaneously. This is usually possible in the case of a shore station. In the case of a ship set, however, geographical separation of the sending and receiving antenna is impossible, and it has been customary, there- fore, to rely entirely upon separation by selectivity and balance. Mr. Brown proposes to introduce another method of separation in which differentia- tion between the sending and receiving channels will be obtained upon a time basis by associating the sending and receiving radio channels alternately with the local low frequency line or other type of signal- ing circuit Preferably, this switching may take place at a frequency higher than the signaling frequencies and lower than the radio frequencies involved. As a means for controlling the commutating or switching operation advantage is taken of the switch- ing function of a vacuum tube. Digitized by Google

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KADlO WORLD 1! At Work on the New Broadcasting Station in Heart of New York City (C Underwood & Underwood, N. Y.) Fnunewotk of the radio room of the new broadcasting station now under construction on the roof of Aeolian Building-, 42nd street between Fifth and Sixth avenues, New York City. Jt Is expected that this important broadcaster will be completed In about a month. It will be one of the finest and most up-to-date stations in the world. How the Wind Blows Shown by Radio ANEW aid to aviators is offered by the Bureau of Aeronautics of the Navy Department by the installation on the 700- foot radio tower at Arlington, across the Potomac River from the Arlington Ceme- tery, Washington, D.. C, of wind-recording devices. A mast has been erected on the tallest of the three towers, on which is a six-foot wind vane, which, by electrical connections records in the office every vagary of the wind cur- rents at that altitude. The records, it is said, will be of exceptional value to airmen in showing the more constant currents of the upper air. The recording device not only shows the direction of the wind and keeps continuous record of its velocity at all hours, but indicates the velocity on pressing a button. By counting the number of buzzes per minute the velocity can be read at any time. The continuous record of wind velocities at 700 feet above the ground will be of ma- terial aid to aerial navigation over this ter- ritory, especially when rigid and non-rigid airships are in flight. Formerly, in order to get the wind velocity and direction, small rubber balloons, hydrogen filled, were liber- ated, and bearings taken on them at inter- vals of one minute with a theolite. The angles, when plotted, showed the speed and directions of the winds that drifted the balloons at each altitude. The height of the balloons at the termination of each minute of flight was predetermined by the weight of the rubber and the amount of ballast lifted. The balloons were usually inflated so that they would rise at the rate of 200 metres per minute. When the sky was clear and cloudless they were often followed, through the instrument, to heights of 10,000 feet or more. There are often times when the fog, low clouds, rain or snow interferes with the observation of the balloons, so that the advantage of having wind instruments on high towers is apparent. While the pilot balloon _ method is still widely used else- where, in the near vicinity of Washington prospective fliers need only telephone to the recording office to receive the readings at any moment. The triple register, as it is called, also makes a continuous record of sunshine. The transmitter, placed near the wind mast, indicates on the register every minute of bright sunshine that strikes the tower. The purpose of the instrument is to show whether there is sunshine or cloud above any low hanging clouds or fogs that may prevail near the ground. Continuous records at 700 feet above the ground level will be compared with those taken at various stations at the ground level, one of which is at the foot of Arlington tower, and will be useful in determining the increase of wind with altitude. The data will also be of value to engineers, the department says, in using the readings for the determination of wind pressures on structures. The Next Big National Event Is National Radio Week, December 23 to 30, inclusive. Why Magnavox is the Reproducer Supreme OFFICIAL tests with the oscillograph prove that the Magnavox elec- tro-dynamic receiver re- produces incoming wave forms with maximum ac- curacy. The Magnavox can be used with any receiving set — the better the set, the more Magnavox can do for you. When you purchase a Magnavox you possess an instrument of the very highest quality and effi- ciency. R2 Magnavox Radio with 18- inch horn if (a» illustrated) This instrument is intend- ed for those who wish the utmost in amplifying power ; for clubs, hotels, dance halls, large audiences, etc. It re- quires only .6 of an ampere for the field. Price $85.00 R3 Magnavox Radio with 14-inch horn The ideal instrument for use in homes, offices, ama- teur stations, etc. Same in principle and construction as Type R2. Price $45.00 Model C Magnavox Power Amplifier For use with the Magna- vox Radio and insures get- ting the largest possible power input. 2- stage $ 80.00 3- stage 110.00 Magnavox products can be had of good dealers every- where. THE MAGNAVOX CO. Oakland, California N. Y. Office: 37* Savaaui At*. Digitized by Google

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20 RADIO WORLD Why I'm Proud of Home-Made Set By A. J. Wets 373 East 204th Street, New York, N. Y. My Over the Top! (Radio Version) "Cloee-up" of Mr. A. J. WeU IN response to the request in Radio World for pictured information, I am enclosing a photograph of the receiver which I built and with which I am get- ting what I consider remarkable results. I regret that I have nothing to offer in the way of new wrinkles or phenomenal hook-ups, but_ I feel that I have suc- ceeded in finding a better way of doing one thing at least, and that is obtaining a well-balanced panel lay-out. This, I find, has been sadly overlooked in most home-made sets and in many commercial sets as well. I have also, I think, succeeded in ar- ranging the accessories that make up a hia home-made receiving wt. receiver, in an orderly and convenient manner. The table on which my set appears, in the picture, is home-made. It contains a compartment in the rear for the B bat- teries, four in number. The cover of the table is hinged, permitting ready ac- cess to the batteries at any time while the set is in operation. On the lower part of the table is a shelf, placed at a convenient height, which holds the A battery. The leads are brought out at the top, through holes drilled in the cover. The battery binding-posts are all in the rear of the cabinet. This gives the panel a neat appearance and keeps the (Cartoon by Lawrence B, Hinckley) conglomeration of wires away from one's hands when manipulating the dials. The loud-speaker is placed in the rear, on a small shelf. This keeps it out of the way and at the proper height. Notice that the amplifier is built into one cabinet with the receiver proper. This cuts down the length of the cabinet by one half. The receiver is an ordinary regenera- tive one, using a coupler with a condenser tuned secondary, and a plate variometer for regeneration. V-T 1 and V-T 2 tubes are used ex- clusively and respectively for detection and amplification. Other parts of the set are as follows: home-made 180 coupler, Mignon condenser, Atwater Kent variometer, Paragon rheostats, Radio Corporation transformers, General Radio Corporation dials, switch points and levers, also a Radio Corporation potentiometer. The following is a list of stations I have copied to date: WTZ, WWZ, WHN, WOR, WEAF, WAAM, WBS, WLAW, WGY, WHAZ, WBZ, WNAC, NOF, WOO, WHAS, KDKA, WOC, WFI, WMAK, WRW, WNAQ, WSB, WIP, WWJ, KYW, WGM, WHB. I have letters from most of the above stations, proving that I have actually re- ceived their programs. While this may not seem such a re- markable record to many radio fans who have covered a still greater distance with their outfits, it does mean a great deal to me, since I built the set myself. Uses Miniature Resist- ances in Plate of Single-Circuit EDITOR, Radio World :— Enclosed is a wiring diagram for a single-circuit receiving set with which I have derived exceptional results. With this circuit and a one-step amplifier, I have heard the fol- lowing stations: KDKA, WWJ, WSB, PWX, WGY, KFAF, NOF, WHB, WOC, WBAP, and others too numerous to men- tion. If you will notice the diagram, I am using non-inductive resistances in my plate circuit which seem to hold my tube steady and prevent it from_ going into oscillations, for which the single circuit set is noted. On several occasions, I have adjusted my set to such a fine degree that I could hear violin music from the lowest to the highest notes without the bulbs going into oscillations. This also makes it very selective. When you ad- just your set you do not seem to have other high-power stations breaking through.— Fred Gretsch, 1311 East Condit Street, Decatur, Illinois. Heok-up of Mr. Gretecn's set u described in hi.

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RADIO WORLD Inductance and Resistance f DON'T quite know what this title means, 1 but for all of that it seems to me rather good. I came upon it in the radio section of a metropolitan newspaper with which I happen to be familiar, says Robert L. Duff us in "The Globe," New York. It was part of a discussion of Oscillations, The Damping Constant, Filter Tuning, Microhenries, Microfarads, and other subjects connected with the miracle of sending a jazz concert or a bed-time story through the air from Newark to Oyster Bay. The miracle was impressive, but it seemed that no one with- out a passionate affection for logarithms and diagrams could have made head or tail of the explanations. I pointed this out to a representative of the circulation department The man in the street wouldn't read such stuff, I said, and if he did read it he wouldn't understand it. What he wanted was simplicity. He couldn't digest anything complex, or— as Noah Web- ster would say — esoteric. The circulation man listened to me pa- tiently. He had but one answer. He didn't know what the man in the street thought about these technical subjects, but he did know that he liked to read about them. There was no doubt about this, for he had figures to prove it. Who read the radio section? Boys and young men very largely. Most boys liked to tinker with scientific toys and many of them knew a lot more about electricity than college professors had known a few years ago. Logarithms and technical jargon were as easy as baseball to these young peo- ple. But the boys didn't have it all to them- selves. Every one who was interested in the wireless telephone learned about it just as they had previously learned about auto- mobiles. Age wasn't a barrier. Men who would have regarded a technical discussion of the economic cycle or European politics as clear beyond them easily got a grasp on the just as difficult subject of electricity. The explanation is one long known to educators. We all learn more easily when we are interested than when we are not. A boy may go to school for years and make practically no progress. Then he discovers that he has a personal need for mathematics or science, and he soaks it up almost over- night. It was interest that was lacking, not intelligence. Probably this is true of multitudes whom it pleases the intellectual snobs to regard as hopelessly stupid. Somehow or other, life has failed to engage their interest except at a few points. There is no reason why the schools, and later the newspapers, mag- azines, and theatres, should not get them ex- cited about a wide variety of subjects. The trouble is that scientists, artistic persons, and others, who regard themselves as out of the ordinary, usually won't take the trouble to tell the man in the street about the thrilling things they know and feel. Yet it can be done. If "inductance and reactance" can be made comprehensible to the man in the street so can anything else that it is valuable for him to know. Another Radio Club THE Highway Radio Gub was organized November 23. Applications for mem- bership may be filed with William C. Burns, corresponding secretary, 2655 Mansfield Any single copy of Radio World, be- gtnahif with No. 1, mailed on receipt of 15 cent* postpaid. Any seven issue* for $140. The full 20 number* aent for CM. Or send S3.M for C months (M num- bers) or UN for 1 year (52 numbers) and have your subscription start from No. 1. Radio World, 1403 Broadway, New York. Place, Brooklyn, New York; or, Joseph F. Doherty, chairman of the committee on membership, 1117 Quentine Road, Brooklyn, New York. The object of this organization is to promote good fellowship among ama- teurs and fans, and to promote instruction and experimenting. Agents RADIO FINDS A BETTER CONDENSER Barley's II-.ooos and 41 Plat* .osiL Iu Plates spaced elaaa give It the am- aat tuning qonlttloa. It la a dia-cast produet; the stationary platan ars east solid, accurately and permanently spaced, on three upright supports, while tbe movable platea are east on the center revolelng spindle. Plate* cannot loosen, which eliminate* sh m Ka». Each condenser has oar money-hank guarantee. Price, tt Plates SS U sack 4a Plate* (S.7S earn TO JOBBKM AND nKAI.aTM A SPLBNMD HtoroemoN Bayley Condenser Co. iaa-10* VaaeVreeer St., BVroeklyn, M. T. "BECO" RADIO FREQUENCY SETS A REAL DX SET TUNED TRANSFORMER TYPE 200 TO 500 METERS 2 RADIO FREQUENCY 2 AUDIO FREQUENCY 1 VACUUM TUBE DETECTOR ALL ON 3 TUBES BISSELL ENGINEERING COMPANY 161-167 WEST 64TH STREET NEW TORE FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 BroUmmj. New Y+rk City. Pltau Mnd mt RADIO WORLD for _ m*mUu, for mmiek pUmu *md inclosed % K — •UBSCKIPTION RATES: VafnflO COlHf (••••miiiikii *9 eU e»eeee«*eee.ee.ee.ee*ee*eeeee.ee*e*e.eeeeees**.e»* Tate* Month* LSf Mm Months Jj» One Tear (9 lasers) Ms Add UM * Yeas far Fa sad Canadian Postage.

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Let Radio World Test Your Goods MANUFACTURERS, **md a nmfb of your good* to our TecWioeJ KottorJPV.4 Oarlw Ehlort, MM Fleaaaat Street, Quoene, Long Ulaad, New York. It wUl no e***ruUy te*te*L If yon good* eatiefy our expert*. RADIO WORU) S *«>oor*o»oot will be paUUbed i> our Boreltt>di.o cWpartaaeat ujthout ck-rgo or ohligaUoa of auy Idas ou your port. Wheat tho radio pur. cLTw Ul7 . publbkod ft i. RADIO WORLD with tko aaul accompanying tkU editorial attached, ko wUl kaow tbar tko prod- act .toad* for porfoetioa aad ka* tko guaraatoo of RADIO WORLD. RADIO WORLD ia roadoriag a *ory»eo tkrougk It* tearing dopartanont that U prompt, accurato aad prooWau roaulta. All good* will ko roturaod to maaufacturor*, aft or teatiag, pro- vided ataanpa aro aoat for tkat purpose. Rheostat Has Novel Contact Arm (Manufactured by Bunroid Radio Co., New York, W. T.) TO overcome the difficulty between the coils ot resistance wire and the contact arm, the Sun- raid rheostat uses a contact which is maintained by the constant pressure of a spring on a small brass plunger. The coils are wound in the ordi- nary way on a strip of heat-resisting compound and then set into a condensite cup so that it forms a ring approximately two inches in diame- ter. To fit the control knob shaft, a piece of nickeled brass is fitted into a clamp at one end and a tube at the other to hold the compression spring and the plunger contact . Either panel or base mounting may be used in adapting this theostat in the set. The condensite cup is pro- vided with screw holes so it may be fastened to the panel. National Radio Week Special Number ! Remember "This 1$ a Radio Christmas" and that millions of dollars will be spent during the holiday time for radio gifts. Be sure to get your share of this business by advertising in the issue of RADIO WORLD of December 23, which will be RADIO WORLD'S NATIONAL RADIO WEEK NUMBER Thru this medium you can reach thousands of readers, who are not only interested in radio themselves, and want new equipment, but who also will give presents to others whom they wish to make radio fans. ADVERTISING RATES: Regular advertising rate* ia force for RADIO WORLD'S NATIONAL RADIO WEEK NUMBER, as follows: $150 a page, fS an lack. Diaeouat, lt% four time*, 15% thirteen Ua.ee. Take advantage not only of RADIO WORLD'S circulation, but also its cash-thru-the-mail pulling power. Be represented in RADIO WORLD'S National Radio Week Number, and reach the many thousands who actually want your goods and are ready and willing to pay for them. EARLY COPY GETS BEST POSITIONS. RADIO WORLD, 1493 Broadway, New York New Firms and Corpora- tions (Tkt trmj and c»rfrmtio»t ***** cahmrnt earn be reached fty emtmg with the attarmeye, ■*«•* are ataen whatever paeama.) Richman Electric Co., Newark, electrical de- vices. $100,000; Max Richman, Daniel Kalisch, Jo- seph Dalessio, Newark, N. J. Capital Increase Electrical Invention and Development Co., Schen- ectady, $25,000 to $75,000. The Coming Events of RADIO WORLD w*. of a* aaaaaa SECOND NATIONAL RADIO DVOaTTlOR. direction IateraatkMul Trad. E**aattJea Ce. Chicago, Tannery 13 to 2*, imoUaiv*. ML Claras A Kin?, director of pnblidty. 417 SeotaDeaxkara Street, Casoago, VSL PERMANZNT RADIO FAIR FOR BUYER*, Hotel Imperial New York City. Open treat September. 192* to Mar. «*. AMERICAN RADIO EXPOSITION. Ora»4 Cea- tral Palace. New York Otr, DaaaUFe SL ColweD * EorfceU. Flak BmiMiag. New York City, directors of pabadty. SOUTHEASTERN RADIO EXPOaTTKW. Aaii- tori us Araaerr. Atlanta. Georgia. Daaeaabei 4 M ♦, uctoare*. Co-* Piesnssos St. SECOND DISTRICT RADIO COWVRNTIOH, Hotel Paaawylvaala. New York City, March 1, I and 3, VD. At the Permanent Radio Fair PERMANENT RADIO FAIR. INC., a centralized exhibit of reliable radio mer- chandise at the Hotel Imperial, Broadway and 32nd Street, New York City, is attract- ing considerable interest among radio buyers and dealers. Only the products of repre- sentative manufacturers are on display. The exhibits, enclosed in handsome show-cases in the attractive Red Room of the Imperial, offer prospective buyers an opportunity to secure a comprehensive survey of the radio field. The radio fair is doing everything pos- sible to boost radio and to stimulate favor- able public opinion toward radio in general and to exclude all whose product is of such character as to bring radio into public disfavor. Another very interesting feature of the Permanent Radio Fair is the radio phe- nomenon, "Madame Radora," the life-sized automaton who bows and talks in human fashion. No Free List To many anxious Inquirers ! RADIO WORLD baa no fro* Int. One copy b •out aa a vouchor to each advertiser or advertising agent represented la current issue*. All other copies are paM for oa subscription or through the new* trade. Digitized by Googl

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RADIO WORLD 23 With the DX Night Owls Wide Range with One Detector Tube E DITOR Radio World :— I have been read- ing some of the long-distance receiving records published in Radio World. I would like to submit mine. I do not think they can be heat easily, considering my equipment I have heard as far east as WBZ, Spring- field, Massachusetts ; as far south as WI AF, Nola Radio Company, New Orleans, Louisiana ; as far west as KHJ, Los Angeles, California, and as far north as CKCK, Regina, CKCK and CJCG, Winnipeg, Canada. I have heard KZN, Salt Lake City, Utah and DDS, DN4, KEAF, and KLZ, Colorado. I have heard broadcasting from twenty-five States and two provinces in Canada. All these stations (75), were heard with only one detector tube, with 22}4-volt battery in plate circuit. I use a home-made, three-spider-web regenerative set. On the night of November 21, I heard WLAG, WGY, WSB, KDKA, WJZ, WDAF, W1AO, WEAF, WHB, WBZ, WW J, WCK, WHAS, WOC, WJAP, KSD, KYW, WOS, CJCG, WEAB, DN4, WGM, WBAP, WDAJ, WBL, WFAA, KHJ, WPA, and CKCK using a one-step amplifier with 45 volts on the plate. I use Cunningham tubes and a Thordarson transformer. I don't think this record can be beat with the same equipment. — Arthur Lindstrom, 4th Street, Baraboo, Wisconsin. * * * With a Home-Made Crys- tal Set EDITOR, Radio World:— In your issue the record of E. S. Morrison, Ashland, Oregon, with a Westinghouse R-C set, in Radio World, No. 34, November 18, 1922. We think we are making records here. With a home-made crystal set we hear WGG, KDKA, WSB, Detroit, Cincinnati, Minneapolis, Fort Worth, Dallas, Denver, etc. With a home-made one-tube set we pick up Los Angeles, San Diego, San Francisco, Portland, Atlanta, Schenectady, Springfield. Havana, Cuba, and Calgary, Canada. If better records are made, who made them? We will make an affidavit as to ours. — N. R. Brown, Olatbt, Kansas. * * * A Claim from New Orleans EDITOR, Radio World : — I am not try- ing to claim the record for receiving. I live in New Orleans, Louisana; but with a single tube and one coil consisting of 60 turns and rotor, I hear regularly Denver, and Colorado Springs, Colorado; Chicago; WWJ, Detroit; KDKA, Pittsburgh; WOC, Davenport, Iowa; Fort Worth and Waco, Texas; Atlanta, Georgia; WSB, WGM, and others. There are three stations in this city. If I do not wish to hear them, I can tune them out. Under favorable conditions I hear Portland, Oregon. How's that? — R Diamond, 413 Royal Street, New Orleans, La. * * « On a Crystal Set EDITOR, Radio World: I have picked up WOC, WCAL, WWJ, WCX, WHAS, WOI, KSD on my crystal set I accomplished this all within the past week ; for heretofore, believing long-distance reception with crystal sets impossible, I never attempted to "get" any distant stations. On November 19 I attempted to pick up WCAL, Northfield, Minnesota, about fifty miles distant I not only got them, but WOC, Davenport, Iowa, as well. Since then not a day has gone by but I have picked up one or two long-distance stations. Although this seems incredible, it is a fact I have heard these stations very well considering the circumstances. 1 hope to better this record before long. — Bill Keating, 1516 Second Avenue, South Minne- apolis, Minnesota. * • * Tuned Out WJZ for WOC 1TDITOR, Radio World: On November J-' 12 at 9 .55, eastern time, with WJZ on the air, I tuned him out and received WOC, Davenport, Iowa, on the loud-speaker; just as loud as WJZ or any other local station. — G. F. Olson, 2 Jerome Avenue, Belleville, New Jersey. Eisemann Magneto Corp. Writ* for dttcription and price* CLARK A TILSON 1 EAST 4ZND STREET NEW YORK Hammarlund Vernier Variable Condenser Atalltd lor For The Hammarlund patented vernier con- trol movea the rotor platei by aa little at 1/S0th of a degree on the condenser scale and it arranged to eliminate all in* tcrference due to body capacity. Therefore poviible to get on the exact wave neceaaary to receive at maximum efficiency. ■•I Mf<L 17 M .SMS Mfd. CM SVi" Bakallta Dial SI .St Distributors Wanted Hammarlund Mfg. Co., Inc. West Eighteenth Street NEW YORK CITY RADIO WORLD as a Christmas Gift Have You a Friend Who Is Interested in Radio as an Amqteur or a Fan? IF so, you moat know that «och a trim* would welcome a yearly anbacriptioo for RADIO WORLD from you. Send ua $*M and we will place tit. name of your friend on oar mailing list for tha coming year, and alto wo will eead a special notification to your friond to tha effect that RADIO WORLD will be •eat for 52 weeks to Us addreM with year coespHmenU. Send fat a yearly order, •o thai tko first copy and oar acknowledgment of your coortegy to your friond will bo received before Christmas. Address: Subscription Department, RADIO WORLD, 1493 Broadway, New York, N. y. Christmas Gift Subscription Blank RADIO WORLD, 1493 Broadway, New York. N. Y. Enclosed find $6.00 for which send Radio World (52 numbers) for the coming year, 1923, to the following address: Same Address City and State. Sty Same Address City and Stale. Send notification to the name given that RADIO WORLD will be tent with my com • plimenta for the coming year. If you with to tend more than one aubacription. write additional namea and ad dre«»e» on a aeparate paper and add S6.00 for each addi- tional •ubacriptioa.

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RADIO WORLD Hie best SOCKET for the DRY CELL TUBE 60c LINCOLN RADIO CORPORATION 1 1( W. (Mil tt. Mamifacturtrt Mew Ye* Othf leak year mm *Mkr eerlai *r utiKitar see) INCREASE YOUR CRYSTAL RANGE by i uno a "rr wrmA-ammtwrn CONTACT IN TOI R CRYSTAL DRKTOI I. It leeetao • assertive sset leetaarly. X. Brian neele saw '• >••*"•. . ». witaetaasi kawr lort*. wltaoot jarrtas set, Pries, wit* lartreetUae, tweaty-tr. eeefi. "PT" CRYSTAL CONTACT COMPANY Bex |(4I BOSTON t. MAM. SPECIAL OFFER Far • limited «m esty RA-M....MI frets CM..... DA-I Grebe RORK... Prleoe F.O.B. Re* Baa*, tt. 1. A. V. GREGORY Brawl Straat ** N. J. PHANTOM-CIRCUIT wum> Tonx own. tm» earnrke yea. No redle froqaa Boy. Oeaslali. Ml with abets at etreatt MM atapaldht VUOO RADIO SHOP. Bn W-7S4. Variometers with dial, Veriocooplara with dial. Money Back if not Satisfactory OS LAND, INC i 122 FIFTH AV. RADIO MAILING LISTS • m Beull Bulla Dealera, Unlud autM par M. $ T.M 1114 Badlo Manufaeturers par Bet. jt.it list Badlo Bupptar Jobber* par Bat, 11.M 1ST Badlo manufacturer, of oom- plete seta POT Bat. 4.M 1*0 Badlo Stall ma par Bat. 4.M 14*00 Badlo Amateur, and Man- acera of Badlo Station par M. T.M NeatlT typewritten and ready to aand you an noclpt of remittance eoaednx the amount. TRADE CIRCI LAR ADDRKB8INO CO. 100 W. A0AM8 STREET CHICAOO. IU. SAVE MONEY ON HIGH GRADE Variable Condensers Direct from Manufacturers Take tbe middleman'* profit and anil- ine eoata for jrouraelf. We aell you di- rect. These extremely accurate lnatru- menta made by experienced condenser people are minus the decorative frllla that add to cost. Price reduced to rock bottom without sacrificing- quality in the least. Satisfaction or your money back. Write today for very Interesting- cir- cular. PRICES: tl Plata $2.55 4S Piste $2.95 Comslat* with Moaatlai Straw, Tour Order Filled by Return Hall Ke aback* ar mo ardor* needed. Pay postman. Sand the order TODAY, eneloatnx t two-eant ataaap* to oarer autlUnc onat and reeelre your eoa- danaM In a day ar two. MANUFACTURERS' RADIO ASSOCIATION ae Baat Kinney St. Newark, N. J. Answers to Readers PATENT Year Radio Iaaeaar. Cellar Writs FREE ADVICEl /INTENDED to construct a cabinet 8 x 15*30 inches. I will divide this into four compartments so as fo_ hold. 1. a honeycomb coil regenerative receiver; 2. A telephone head set; 3. Battery; 4. My 6-volt A battery. My A battery will be about 12 inches from the receiver. Do you think this will interfere with satisfactory reception?— John Mullenhauer, Poughkeepsie, N. Y. The length of the A-battery leads make very little difference in the efficiency of a set. The length you mention is all right, a • * Can I use Westinghouse type WD-W tubes for amplifiers? If so, what kind of amplify- ing transformers must I usef Also, what kind of grid condenser and leak will I need for the detector tubeT—W. E. Gilbert, Jr., Box 1282, Alliance, Neb. WD-11 tubes may be used as amplifiers. The regular standard transformers may be used, but the Sleeper transformers work best with this type tube. It is not essential that a grid condenser, or leak be used with this type tube, but we advise you to try it out as an experiment. A .00025 mfd., condenser will answer the purpose and a 1 -megohm leak. a a a / hove a two-stage honeycomb outfit with 100 feet of aerial. I was receiving WJZ and WOR wonderfully. I disconnected my tuner and replaced it again exactly the way it was before I removed it. Now my receiving is reduced fifty per cent, in loudness. I have tested my batteries, both A and B, and And . them fully charged— Paul Haffner, Wood- cliff e, N. J. Undoubtedly the trouble is caused by what is known to radiomen as "fading." This is a condition over which we have no control. It sometimes happens during reception, and frequently becomes so loud that the vacuum tubes are paralyzed and reception ceases. Then it is a good plan to disconnect the B battery, let the tubes recover, then replace the B battery with the amount of voltage somewhat reduced during the period of the maximum reception. Try smaller coils on the secondary and the tickler. * a * / would appreciate a diagram with com- plete directions regarding the construction of a radio outfit. — Herman Brush, Mt. Carmel, III. Radio World, No. 33, dated November 11, page 4, will give you a complete diagram and all the necessary data you need. a a * How can I make a charger for alternat- ing current?— C. E. Chamberlain, Jaffrey, v N. H. Purchase a battery charger from some re- putable concern. These chargers are more efficient and compact than most troublesome, noisy, home-made affairs. * * * / have a regenerative set with one step of radio-frequency amplification. I cannot re- ceive long-distance stuff except the local sta- tions. Will you please publish a good hook- up?—Reader 319. Louisville, Ky. (Continued on following page) Sub- year O WORLD. $6.00 a $1.50 three months. Quality, Dnion + WorlpmaniMp + Notarial = RELIABILITY Simple to Use , J«*t plug In at \any 110 v. A. C } lamp socket at- ftach cBps to bat- tery— tara aa ear- rent and yoa nave your own charg- ing plant. A compact portable Recharging unit that will rally charge a WO AH battery overnight (or Sc. to 10c At your dealer* or write Kmc Electric Mfg. Co, Inc. i AveeatM BuBTals, N. Y. STANDARD HBADSBT 1.5** OWN rrMWofsy*- $5.75 Standard Electric Saba Co. eMSWaaaefsaap ewfa wP* FOR CHRISTMAS $4 "The Little Wonder" CRYSTAL SET $2.50 UNMOUNTED Just the gift far your boy ar gat. prepaid. Free rateleg oa GUARANTEED, Galena and **» TESTED CRYSTALS Radiocite. .. >wt~ Radt-O-Plate Panada. All aesee cut to artier. Holloway Electric Supply Co, Inc. nt Third Avenue New York City Do Yoa Like Clear Tone— Sharp aad Distinct? If so try MARSH'S Vernier Variable Conde— » AT LAST Made In Three Styles. I sad Screws Complete. Pally Om tT-Plate SS-Plste • B4.W U-Plate O S4-SS Mall orders promptly ailed. F. P. Marsh, 145 Nicoll St NRW HATEN, CONN. RADIO SALESMEN! A Rare Selling Opportunity For Lire Wire Men Handle Grewol Detectors in territories not opened. Write for full particulars RANDEL COMPaANY f Central Ave. Newark, N. J. Do Your Buying: At PERMANENT RADIO FAIR Hotel Imperial 32nd Street and Broadway New York City Buyers — Dealers — Radio De- partment Managers, Demon- strations of Any of the Pro- ducts of the Exhibitors. Only Products of Representative Manufacturers Are on Display. Nearly 100 Manufactnrera Now Exhibiting Digitized by Google

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RADIO WORLD 25 Pignolet RADIO VOLT-METER ONE INSTRUMENT MAKES ALL TESTS Write for booklet with for teitinf end adju.tinf Radio Sot*. iow in ui Pignolet Instrument Co. , Inc. 114 Liberty Street, New York, N. Y. Answers to Readers (Continued from preceding pagt) PRICES SMASHED Saab Ml* b*a ■■nil mm Mass Md «*e»aa*«a RKGKNKRATIVK VACUUM TUBE NET Appnalaut* t*M*— l.tltalto*. ____ Oar nie Own r»il itiliT drllM. 11.75 ll.tl CeMaat *f »-*» Ml «• M port-- I.M ••}• TOT dtobj M* IS*. MS 1* MriUb point* wllh not. B*. I*. . .It .4* 4 ailtek now elib nut- I*.... .14 .1* I Madias pom*. Nie».l pUud # I* .24 -«» i OTlue lew« 0 Mr ... .»• ••• 1 Hum iMoneL Bit*** mat. .ft 1 mm ewetar. ftert**at*a*. . . . MS 4.JJ 1 If pl.t. »rl*bl* imliiiir 131 •.»« 1 tab* MM- MOThM -41 J* I pM MMM udkit J M 1 itat urn I r It •US*r— kaatkad darn Puol drllkjd It.tt tt.tt T*o rup aapUAar uaaoblad. In •ablMt It.lt tt.tt Taai tab* Mt t* mMbN T1 It". Wind I7.lt tl.M a*** tar Hat Mew or •mm mM mm la •MM. YOU MUST «t PLCA8I0. Radio Parts Manufacturing Co. II rmrfc Place West Detroit, Mich. Latest broadcasting map 15c That is, a complete broadcasting map appeared in Radio World. No. 8, dated May 20. Mailed on receipt of 15c. Radio World Company, 1493 Broadway, N. Y. C (AdrM In this issue there are two good hook-ups of radio-frequency. We advise you to see Radio World No. 19, dated August 5, in which apeared article on radio- frequency by George W. May. This should set you right in fixing up your set. a a » Please publish a hook-up with a vario- meter m series with the primary of the loose cov pier T — Harry Homer, Glen Cove, L. I. The above sketch shows the correct hook- up for such an arrangement. Care should be taken in checking up all connections and bat- tery polarities. a a a / am planning o l-tube hookup as illus- trated in Radio Would, No. 30, dated Oc- tober 21, page 7, and would like to add one step of amplification. Pleas* send me a wir- ing diagram. — Richard Burgess, Burlington, Vt. There appeared in Radio World, No. 22, dated August 26 an article by Fred. Chas. Ehlert, "My Detector and One-Step Ampli- fier." This describes the exact receiver you have in mind. A complete diagram is also published. a a a / am building a honeycomb coil regenera- tive set. I am told that if I short circuit the tickler coil I will get efficient spark re- ception. Would there be any advantag • in using loading condensers to load the primary and secondary of my set to larger capacities T — Maxwell Murphy, East port, Maine. Do not short circuit the tickler coil or the signals will be very weak. See Radio World, No. 24, dated September 9, page 9. VARIO COUPLERS $1.25 List Wa eiao mmka $ of W ttylm That List $2.50 up Jobbers — Dealers — Agents Write for Diecouta Jewed Radio Sales Co. ft Went St. Now York City American RADIO Exposition The Official Exposition for American Manufacturers with the endorsement of the NATIONAL RADIO CHAMBER of COMMERCE and sanction of the Radio Apparatus Section of the ASSOCIATED MANUFACTURERS of ELECTRICAL SUPPLIES Grand Central Palace New York December 21st to 30th (Sunday enwpted but Ckrufeka* Daw This first really comprehensive Exposition to be staged in a manner worthy of a great in- dustry includes such represen- tative exhibitors as: Wfetera Klertrle Compear, be. Ba*He Canieratlaa of AmerUa Mai itJeaal Ca wiaae'ia. leeatat* , Kxreatrre Kettle CeaejeU Cete-CeU Cm Weatea Btor Ami i liae Bed** Wiley eti.Mben-Tartaoa Mf*. Oe. HeMaer-raaot CMpa-RaatMii DaUUer C< Defer «raea Co. All of the above and other lead- ing manufacturers have con- tracted for space and many more are at present negotiat- ing for representation. The opportunity to display Radio products to thousands of buy- ers during the holiday season is an unusual one. The expo- sition will be one of New York's big features in connec- tion with National Radio Week. For further particular! write or wire AMERICAN RADIO EXPOSITION COMPANY 1XS BROADWAY. NEW YORK TILIMONI JOHN tOOS

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RADIO WORLD Special Xmas Radio Offerings to RADIO WORLD Readers . Complete $29.25 Special $15.50 No. 6 Federal Junior 1- Complete Antenna kit Dictograph phonea J No. 7 Federal Two Step Amplifier Regular Price Prices lower than ever before, and, perhaps, lower than they erer will be again, this opportunity while it last*. The items listed below are guaranteed, as are all Radio supplies, and are standard, advertised products. No. 1 DeForest Regular Xmas Everyman price consisting of Receiving set Dictograph phonea Antenna kit No. 2 DeForest Tube Set (£or W volt) No storage battery Receiving set Dictograph phones Antenna kit W D 11 Tube (Xji volt) "A'1 Battery "R" Battery (Eveready) No. 3 DeForest Two Step Amplifier 2 W D 11 Tubes" Grasp Penn Special Xmas 29.25 15.50 Completely equipped same as No. 3 } .Complete 58.oo 29.50 ayi volt) 2 "A" Batteries 2 "B" Batteries (Eveready) Telephone ping; . No. 4 Consisting of No. 2 and No. 3 complete No. 5 Little Wonder Crystal Set Dictograph ■) phones 1 Complete Antenna kit J Complete 55J5 29.50 113.75 57.00 2025 10.00 No. 8 Turney Monoplex 054 volt tube set) ■» Completely equipped U same as No. 2 J No. » R C Set complete with 3 tubes "A" Battery (Eveready storage 90 A H) 3 "B" Batteries (Ever- eady 22J4 and 90 volts) Antenna kit Dictograph head set Dictograph loud speaker 2 telephone plugs No. 10 DeForest Reflex D 7 Complete with loop (3 steps radio, 2 audio on 3 tubes) 3 tubes "A" Battery (Eveready storage 90 A H) 2 "B" Batteries (Ever- eady 90 volts) Dictograph head set Dictograph loud speaker 2 telephone plugs 58.00 62.00 29.50 32.50 21725 175.00 189.50 175.00 PENN RADIO CO., 146-150 WEST 34TH STREET NEW YORK CITY Mail Orders Filled Use This Coupon •8 t % : i % A i i 1 8 ; s '. +* 6 " 1 ering items r and will shij ly yours, | e itee each Very tru Ite name : S i ; 3 : M : s • o *» >> Please o"S - order jnderstc ^» s a A Complete Success Radio World Reader So Describes His Tests with Mr. C. White's Radio- Frequency Regenerator EDITOR, Radio World: — I believe your readers will be interested to know that the radio-frequency regenerator described by your correspondent, Mr. C. White, in Radio World No. 28, dated October 7, has proved, in my case, a complete success. Using the new circuit I can hear distinctly, practically all the important broadcasting stations east of the Rockies. I have made just one change in Mr. White's design, and that is the use of a plate variometer instead of a tickler. The value of the circuit seems to be, however, not so much in long-distance reception, as to the remarkable purity of voice and music, due to the use of a crystal detector between the two bulbs. I am using Myer bulbs as I find that their stability is a great help in securing good results.— G. L. Michaud, 1020 Hill St., Ann Arbor, Mich. * » * Trying Mr. Miller's Hook- Up. EDITOR, Radio Worlds — In your issue No. 30, dated October 21, you publish a novel hook-up by Mr. W. Miller who uses a honeycomb coil for tuning. In your issue No. 34, dated November 18, another of your readers claims that he bettered Mr. Miller's circuit by using a variometer. I claim to have had practically the same circuit in use since April 25. It works bet- ter the way Mr. Miller has it hooked up, with the exception that the condenser is across the honeycomb D-L 75 instead of D-L 50. I have tried out both against mine ; and, I think that, next to mine, Mr. Miller's works the best. I would like to hear from others. Just a "bug."— Ray Chittenden, 37 Petrel Street, Rochester, N. Y. DELICATE SOLDERING Both the manufacturers' and amateurs' problem on all fine work is readily solved by the instrument constructed for this particular purpose. THE POST SOLDERING IRON Platinum Heating Unit — Interchangeable Tip — Universal Current On* Half Actual 81sa $6.00 From Your Dealer or Write Awarded Certificate of Excellency, N. Y. Evening Mail Radio Institute POST ELECTRIC COMPANY, (Dir. 509) 30 L 42nd St, New York THE ONLY GENUINE AND GUARANTEED "All Wave" Coupler TRADE MARK * FLAT AND BANK WOUND Wave Length, 150 to 3,000 Meters Eliminate* Fftr tha Navisa . The 811 efficient hook-ups given free with each ■ vi in nweino Coupler enable* the greenest notice to attain the i the me of »U Variometers. Varioeouplsrs and Loading Coils. Inas- much as It performs in one com pact unit the functions of all of these devices combined. "All Ware" - — . same r.-sillts attained by the expert In building the simplest, most compact and moat efficient radio receiving set possible. .For the higher wave lengths that have been and will be allotted to broadcasting stations because of their erer- BUIX.D a set that cannot become obsolete. Be Prepared— increasing number. Unutlial B AtuHt fltlsinAd Individual users of the unusual HeiUllf HlUinea written us that In Rhode Island it is unusual to bring In stations aa far south Alabama, Newaik, N. J„ Is brought in dally ****** °! .!«"Jt«tiOII|— bjck to operatou .d^rUsedT Loo) "AU Wave* ode I Havana, Cuba Coupler have _ .t is nothing while in M., hi I.-. trademark, "All Wave.' $9.00 All Wave Coupler, which is guarant y back to operate as advertised. Look for th< on the rotor, also the alx efficient hook-ups In the box Six efficient Hook-ups sent npon receipt of 10c. ■tamps or Ft— with each "All Waem" Coupler GUARANTEED WITH AN ABSOLUTE MONEY-BACK GUARANTEE THOUSANDS OF SATISFIED USEES Capitol Phonolier Corporation WZ'"0* Patents G rested Street City

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RADIO WORLD 27 GLASS Values J4 U> S ENCLOSED GRID LEAK Guaranteed 35c. Resistances vary from LINCOLN RADIO CORPORATION IIS W. «5th St. LOW RADIO PRICES All new. fresh stack. Satisfaction guar- anteed"" or money promptly refunded. Write for our free MONTHLY BUL- LETIN giving np-to-mlnnte radio prices. We pay transportation on items listed below (East of Rockies) when order totals $15.00 or more (except Storage A Batteries and Homcbarger sets). Oeiaslete Cryrtal Receiving art *J » Frast Feeeo (Denote) 2.000 skate *00 Keysteao Aogreved Arreeter I.J* .0005 Grid Cendeneere Jjj .001 Please Cendeneere t-.-ii-u; ■** Varlsblt Oeud. Mounted. 43 plats $*.00, 21 ■lata 3.00 Variable 'bold.', no dial or «neb, 43 slats $2.76. 21 slate f-JJ Tuning CM. Rain. 1,000 niton. ........ . 2.80 Loose Coupler, Rasge 200 to «00 Meters... 0.23 Audit Am». Treaefensere Thsnlarws. 3 ti I Ratio Pur-A-Fersi. 3 ta I Ratio 3.00 All-Anerloaa. 10 to I Ratio 3.30 Vacuum TubM (New, Net Rebuilt) UV-200 Radlotren (Deteeler) 4.30 UV-201 Radietron (Ansllfler) 6.63 Heady Ooaialete Soldering Sat 1.00 Sockets Nickel tube, libra bate 45 Psnelaia tube aad bate 40 Moulded eomoeeltlon 45 "Star" fllaiaeat rbeoctet, knob aad dial 00 "Magaavex" kud leeakor 42.00 Plan-O-Phoae — A dandy loud weaker 3.30 "Alr.Way" Vorienutsre .8.50 "Air-Way" Verio-Coupler 3.60 Nickel bludloa setts %" high, ser doz. . .40 Spaghetti tubing, rubber 3a. ft. Caabrlc lie. ft Ns. 14 Tinned Butbar Wire, per ft 02 • V. «0 An*. Storage A Battery (40 lb.). 12.00 6 V. 35 Amp. Storage A Battery (45 lb.). 14.00 "Heailbarger" for charging iterate batteries at hesie. Worke en any 100-113 volt, 00 cycle. A. C. circuit 15.00 Write for Monthly Bulletin Holmes Electric Company LIBERTY VILLE ILLINOIS {Suburb of Chicago) The Latest and Moat Essential Part of an Efficient Tube Set Variable Grid Leak and Micon Condenser (Combined) Obtainable In an unbroken ran** trees aero to 5 megohms all Intermediate peanuts. Fixed capacity— .OSOtS at. W. Improves your set wonderfully by Clarifying Signal* Lowering Filament Current Increasing Battery Life Eliminating Hissing Price Only $1.00 At your dealers — otherwise send us pur- chase price and yon will be supplied without further charge. Manufactured by mniESHl^COMPANY,liic. VJ Beekman St. New York City Home of Micon A Antenella R The Biggest Show on Earth ADIO played a great part in the foot- ball contests of the gridiron season which closed Saturday. The seating ca- pacity of stadiums no longer limits the number of people who can enjoy the plays, the cheers and songs of the collegians, says "The Times," New York. One of the fea- tures of the season was the broadcasting of the Princeton-Chicago game by station WEAF in New York. A long-distance tele- phone line connected the microphone at the Chicago gridiron direct with radio ap- paratus in New York, so that the entire country was in tune with the game at Stagg Field. Radio has made it possible for those listening in to hear the songs and clamor of the crowd even before some of those assembled at the gridiron: Sound travels approximately 1,000 a feet a second. Radio travels 186,000 miles a second. The music of Harvard's band in the Yale Bowl, Saturday, November 18, surged through the bowl at the slow speed of sound, but the radio microphone picked up the music and sent it through space at the speed of sunlight, 186.000 miles a second. By the time people 1,000 feet away from the band heard the Harvard and Yale music, radio had transformed the same music into ether waves, with velocity sufficient to carry it around the world seven and one-half times, while the sound waves were covering 1,000 feet across the Yale Bowl. Radio provides the biggest show on earth at the present time. The radio audience numbers millions, and consists of people representing every country in the world. The cast of the radio show is unlimited ; all the world is the stage. And as all shows hold feature performances so does radio. World series baseball games, play by play, direct from the diamond; prizefights direct from the ringside, blow by blow, mingled with the sound of the gong and the outcries of the crowd; football games direct from the gridiron, yard by yard, backed by the college songs and cheers; track meets, lap by lap, and now the latest feature added to the program is opera. Radio Times Changed LAST year at this time radio sales man- agers were sitting in their offices with the doors locked to prevent the entrance of dealers who wanted to buy apparatus, says "The Mail," New York. The sales man- agers were very independent. Sometimes they would do a man a favor by booking an order and sometimes they would not. Some- times they would grant a man the courtesy of an interview, but more often they were inclined to "turn him down cold." The writer commented on this last spring. These sales managers were told that they would some day change their opinions. Things are very much different today. The sales manager's office is wide open, but the average office is empty. Frantic dealers are sane, and they are not in the habit of mak- ing pilgrimages to the sales managers' sanctums. Instead the sales manager is mak- ing frequent calls on the dealer, and the feet that used to rest on the desk-top are now coming in contact with the hard pave- ment of the streets. No Free List Radio World has no free list. The only copies sent out by the publishers are to fill the ever-increasing orders of the American News Company, the large numbers of subscription orders received at the office of publication, and one voucher copy to each adver- tiser and advertising agent represen- ted in current issues. Radio World, 1493 Broadway, N. Y. Watch for future announcement*. Spinel -MMO EOIJIPMENT MFC. C<* Dest "B," IUI JEROME AVE. NEW YORK. N. V. WE DEFY COMPETITION Dictograph Phones, $S S» Dictograph Loud Speaker, $13-S0; list, $20.00 Home Charger, DeLuxe Model, $13.50; list, $U-St Brach Out Door Lightning Arrester, $1-S0 Triple Coil Mounting, $ZJ»; hst, JS.00 Radio Frequency Transformer, flMf Bst, $3 M Perfection Radio Corp. of America lea W. 23d Street New York City RADIO' ■ late use SPECIALS Baldwin Phones $12.00 Double filament Audlotrons 2.7S Mahogany Variometers ZSt Send 10c. for new and complete catalog EMPIRE BADI0 CORPORATION 271 W. 12STH STREET NEW YORK CITY FINCH RADIO MFG.CO. I I 303 FIFTH AVE , N Y.CITY. "* At Your Service! There appeared in RADIO WORLD, dated April 1, 15, and 29, the. following articles: April 1— A 500- Mile Radiophone Employing a 5-Watt Tube, by Frank A. Hahnel. "Tell Me, Please, How Will This Set Receive?" by E. L. Bragdon. Short Cuts in Receiver-Cir- cuit Design, by O. C. Roos. Making a Short- wave Regenerator, by Fred. Chas. Ehfert. April 15— First Principles of Electricity as Applied to Radio, by John P. Miles. Your Storage Battery, by E. L. Bragdon. What Makes Radio Possible, by Edward Linwood. Ground Connection as Vital as Antenna, by Fred. Chas. Ehlert. April 29— Valuable Pointers on Aerial Con- struction, by Edward Linwood. What Is Meant by Tuning;, by E. L. Bragdon. Radio- Frequency Amplification and Regeneration, by Frank Armstrong. Honey-Comb Coils and Con- densers, by Edward Linwood. Charging the Storage Battery, by E. L. Bragdon. How to Construct the Variocoupler, by Frederick L Rumford. Each copy sent on receipt of 15c. per copy, or the three copies for 45c.; or better still, send your subscription beginning with any one of these numbers, and we will send this paper for 52 issue, and you will then have a complete file for ready and contant refer- ence. RADIO WORLD, 1<* Broadway. New

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9 RADIO WORLD R-C CABINETS MifeMUMM* Phseesraat Qaslrty Flaws. Ns OrW- IH si ssssls fsr attasblai reaulrad. Hlsged tsa. RETAIL PRICES 7x« 81.58 7x14 «S.M 7xl» «Z.7S 7x18 UM 7x21 9400 II year dealer eannst supply yes, (Not direst THE R-C MILLS Exetstlvs Of low, SO E. 28d St. New Ysr*. N. V. (Mention RADIO WORLD) TOBACCO HABIT BANISHED QUICK, SURE, LASTING RESULTS Tobacco Redeemer banishes the habit com- pletely, almost before you know it. An absolutely scientific, thoroughly reliable treatment. No matter how long- the habit, or in what form used, you will have no craving- for tobacco after you take this pleasant, inexpensive treatment. This we positively guarantee. Your money returned without argument or question if not satisfied. Write for free explanatory booklet and proof of what Tobacco Redeemer has done for men addicted to the tobacco habit. Send post card or letter today. ■•well Pharmacol Co, Boot 971 , SL Louis, Mo. GITHENS TRUTONE RADIO HORN— LOUD SPEAKER First one to sell on ten day trial Money beck Guarantee Retail Price $21.00 Includes Loud Speaker Trutone has been pronounced the bast on the raaraet by experts. It has a clear, true tone Etery radio fan should try Trutone and compare It with others. If YOU don't And Trutone the beat, your money will be refunded. It Is sold on a ten-day trla! money-back guarantee. If not carried by your dealer write us. Distributors and Dealers, write! AUTO PARTS MFG. CO. 1815 Trembly Ave., Detroit. Mich. FRS ALL MOLDED UNIVERSAL COMBINATIONS C Units la S F. B. B. Melded Variometers F. R. 8. Melded ▼arleeooplers 0S.00 F. R, 8. Melded Bank Windings. . . •*.** Bank Windings are Interchangeable for direct mounting on either Variometer or Tartocoupler. Universal — Accurate — Interchangeable A Complete Two-Stage Long Bangs Receives- Bet Includes two Federal Transformers, Condenser, two-molded variometers, molded varlocoupler, three T. T. sockets, filament rheostats, dials. Read 'In blading posts, switch points: In attrac- tive cabinet and drilled panel: complete, ready to hook up. A $ltS Radio for $40 F. R. S. Radio Corporation 400-D East Fort St. Detroit, Mien. RADIO WORLD TEUEPHON*. BRYANT 4T98 PUBLISHED EVERT WEDNESDAY (Dated 8ATUHDAY OF SAMS WEEK) FROM PUBLICATION OFFICE. 1498 BROADWAY. NEW YORK, N. T. BY RENNE98Y RADIO PUBLICATIONS CORPORATION ROLAND BURKE BENNESSY, PrssldSBt and Editor M. B. BENNESSY, Vice-President FBED S. CLARK. Secretary sad Manater 1493 BROADWAY, NEW YORK, N. T. ASSOCIATE EDITORS Robert Mack ay Fred. Chas. Eblsrt SUBSCRIPTION RATES I Fifteen cents a copy. $(.00 a year. 11.00 far «ur months. $1.50 for three months. Add tl.00 s year extra for postals to Canada and forslsn countries. Receipt by new subscribers of the first copy af RADIO WORLD mailed to them after sending la their order. Is automatic acknowledgment of their proportional rates. Advertising- rates on request ADVERTISING RATES t One pace: One time— 1150.00. Half, Quarter, Third and Two-thirds pases at proportionate rsteas Ons Inch, one time— 45.00. Per scats Hns. $0.40. On four consecutive Issues, 10% discount. On thirteen consecutive Issues, 15% discount. Cover and preferred-position rates made known on application. Terms: 80 days Nat. t% 10 days. CLASSIFIED ADVERTISEMENTS: Fire cents per word. Minimum. 10 words. Dis- count of 10% on 4 consecutive Issues— 15% an thirteen consecutiTs Issues. Cash with order. Entered sj second-data matter, March 18. 1988, at the Post Office at New York, New York, the set of March 8. 1879. IMPORTANT NOTICEi While every possible care Is taken to stats correctly matters of fsct snd opinion In technical and general writings covering the radio field, snd every line printed Is gone over with a scrupulous regard for the facta, the publisher disclaims any responstblllty for statements regarding questions of patents, priority of claims, the proper working out of technical problems, or other matters that may be printed In good faith and on Information furnished by those supposed to be trustworthy. This statement Is made in good faith and to ssvs time snd controversy In matters over which the publisher cannot possibly havs control. 10 More Broadcasters THE list of commercial broadcasting sta- tions operating on 360 meters was in- creased by the following ten during the week ending November 25 : WOAK— Collins Hardware Co., Frank- fort, Kentucky. WPAC— Donaldson Radio Co., Okmulgee, Oklahoma. KFGH— Leland Stanford Junior Uni- versity, Stanford University, California. WOAH— Palmetto Radio Corporation, Charleston, South Carolina. WTAC— Penn Traffic Company, Johns- town, Pennsylvania. KFDC — Radio Supply Company, Spokane, Washington. WRAA— Rice Institute, Houston, Texas. WTAU— Ruegy Battery & Elect. Com- pany, Tecumsah, Nebraska. WO AN— James D. Vaughn, Lawrence- burg, Tennessee. WOAL— William E. Woods, Webster Grove, Montana. Radiophone in Each Room ACCORDING to Michael Emmett, the Palace Hip Theatre, in Seattle, Wash- ington, holds out a novel inducement to the artist in the way of a radiophone in each dressing room. Here the artist can sit while making up, or between shows, says "Vaude- ville News," and hear lectures, sermons, music, etc. Its effects are marvellous, for the artist keeps out of the wings, being inter- ested in the radio, and happily forgets that evil tendency of "talking shop." This seems to be a new blessing to the theatrical world. Mr. Joseph Muller, manager, and the stage hands do all in their power to bring happi- ness to the artists while playing in Seattle, according to Mr. Emmett. lie H0MCHARGER AUTO or RADIO B A T T K R T lor a Nickel. Prist, $ I8.lt tend lor FREE Bairttla DEALERS— WRITE HOW I Tat Automatic Electrical Devices Co. Wast Third SL. CIs- 0. INSU-LITE P A N E L S 1/8" — M per so- In. J/l«"— .015 per eq. In. 1/4" —.91 per Bq- In. DEALERS : Writ* for MtomXM. General Merchandise Co. 14S Market Street, Newark, It. I. IS YOUR TELEPHONE HEAD SET WEAK? Let me remagnet- ize it Guaranteed, in one day good as new. n .50 Par Set I rewind for higher oh ma (a. All radio telephone repairing at mod- erate price*. Mail orders attended to. Dealers write. ROYS, 101 West 42nd St, N. Y. THE GOODMAN The Niftiest Short Wave Tuner on the Market Only MM A PP on 1 lb. Send for pamphlet. L. W. GOODMAN DREXEL HILL, PA. Malar , Halifax., N. 8.. writes: DedtlrM. Reoaived Schssectaey snarly sa see tubs tint Mass I trisS U>» GOODMAN. Wsaid have saves tree Ms as* aseaey by buying rssatbs ags. DEPENDA] GUAR ANT] ASK YOUR NOVO MANLFACTl 424 -43 a W. 3'3 531 SO. DEARBORN ST. CHICAGO. . > ^ri 'lay DEARBORN ST.(

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rad/o world I'hono-Phaae Permaneat Baette Detectar in* eaty aaad redie ckurtv leuairlaa) i af errata! Pruden Reliable Radio Specialties For Gooc/ Results ! THE name "Pruden" back of stand- ard Radio Equipment is a guar- antee of mechanical excellence, perfection of workmanship and scientific correctness of design. Now, more than ever, when the market it flooded with inferior goods, it pay* to buy standard trade marked products. * You can pin your faith to "Pruden." Money- back unconditionally if you do not get com- plete satisfaction. Just a few leaders of Pruden Reliable Products shown here that will give you better radio results at no greater cost. Dealers write today for our interesting proposition, k„..„« M..id^v»r.«»«fr FREDERICK H. PRUDEN INC. AJai Socket Rhroetat A derlee for which amateura and profae- mall Ian Ions bean ml tin*. KUa- ilea WtrlM between MXkM an • 9 An MIL LIB »£.Uv Deed !■ Plaee Of . tftruun ism deserter. Orree mmm quality ef seund wllbsut dlstartlea. MMB or tab* nnliei Detects teletrspk etsaek) at set era] tbeuasad alias. Detests ereaeV aasted neale aara clearly thee anal tuka eauvter. aad ragalrai aa saanaaaa- tlan arbara lbs taaaalag atgaal has aatl* dart aueaata te atuaia ika neslslra phone*. IdaaJ far aa* la ranaaratrat atresias, Uandaaaaa, aubauacUL aaliaaai tar an- omaly la tha laaat rsdSe eaweeaoaa, Ousraateed mlM terperfeetlea MM or Uulu eparetloa. Uat seek.. etede af ■ rpaeUl oocopoottlon— ertresseb; IUM la weight aad durable. Wan lerurth ranges frees lie la it* Maun. Teneleale eeneealeaUy arranged la afford easy eea- aaatlana aad a raid rraaalai tamlnal wires. 993 Bergen Ave. lu. ... *5 00 Jersey City, N. J. The enry porfest at taka apan n asks laaart tha uraoaaai lata the "Hal an" * prrfart aaaaarttaa a* aada. aa esa- atrartad that paMag at laa ear. ajakaa tb. e.r~tu« -are aeattlea. f W. J. Burns to Speak on Police Radio HOW radio is employed, and may be em- ployed, by police and other agencies for the detection of crime will be demonstrated in an intensely interesting manner at the American Radio Exposition, Grand Central Palace, New York City, December 21 to 30, inclusive. William J. Burns, chief of the L'nited States Secret Service, is much inter- ested in radio and is using it in his depart- ment. He will speak at the exposition. In accepting the invitation to speak, Mr. Burns said: "It will be interesting to compare the archaic methods of criminal investigation of the past with the methods of the ptesent; also, what we hope to do in the future with radio — which is the last word. I will ex- plain also how we expect to use radio in the next Bureau of Identification which we are at present organizing in my department." Several demonstrations will be made to show how radio has been employed by police chiefs of European cities. A concentrated effort is being made by the management and the numerous exhibitors participating in this exposition to make it thoroughly representative of what is best in the radio industry. Many unusual "stunts" and demonstrations are planned. Additional contracts for space were signed by the following concerns: Jcwctt Manufacturing Corporation, American Radio & Research Corporation, Electric Storage Battery Co., Ackerman Bros. Co., Inc., Elec- tric Record. Feri Radio Manufacturing Co.. General Lead Batteries Co.. Copper Clad Steel Co. Someihirut Brand New in AritermaWre Jobbers and Dealers — Stock this now for Fall Trade The reault ia extreme sensitiveness, and aa increase in the range and clearness of any art. from the aimpleat crystal type to Uat finest V. T. Receiver. Parked in neat cartons ot 100 (eet, 300 feel and 500 feet. Here is an Antenna Wire that will at < appeal to the radio enthusiast. Il has a real selling argument in that it ia different and better than any makeshifts to date. This new wire, bard draws from the finest copper, hat a corrugated surface with 10 collecting points on its circumference This gives a greater collective suriace and the points girt a greater gathering surface. Price) SZjM par hsmdrsxl Order direct or from your dealer Point It East! A MILLION-WATT vacuum tube has •** been built in Schenectady which is ex- pected to carry radio-telephone conversation across the Atlantic. We sha'nt mind, as ,onK as they keep it pointed east.— "The Plain-Dealer," Cleveland. YOUR NEWSDEALER win deliver RADIO WORLD to your horn*. In order to ba aura of getting RADIO WORLD _ and ot not missing a single Issue, wa suggest that you either subscribe direct or tJkreugk yawr deader at M.as a year (SI issue*). S3.es ail months, and SI S* three months. Or instruct your to deliver RADIO WORLD regularly to your home each week. Dealers will taka steading make deliveries of paper whenever requested. Radio World. lesj Broadway, Now York. Your Filer of RADIO WORLD 52 Wwaks for UM SEND IS THE NAME OF YOUR RADIO CLUB Alee the names of your president and other otTrere We want to e<M three to a "as. af radio elube and ofTWrs we are preparing for publication In an early laeua RADIO WORLD, lilt Broadway. New Tor*.

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JO RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS 7 TRY THIS DEPARTMENT AT U A WORD RADIO WORLD S QUICK-ACTION CLASSIFIED ADS ■wrfci^r whs vmAs ttoAck stare OS" RADIO WORLD woB I RADIO WORLD QUKX- ACTION • U% far U !■ . RADIO WORLD CO, : ecsVsn n short tstd then It par* ta> fa RADIO WORLD ' AD. DEPT. fa 'm^it. Y. c: ATTENTION I Yon invent it Ul u make it. Models, din, manufacturing. Sheldon Tool Co., Roacdale Station, Kanaas City. EDISON B. BATTERY UNITS— One poaitiTt and one negative plate for 10c. IS seta will make a 24-voit battery. Wilkinsburg Wireleaa Shop, Ml Pcnn Avenue, Wilkinsburg, Pa. LOUD SPEAKER FOR ANY CRYSTAL SET. Hear music over entire house. Easily con- structed by amateurs. Eliminates Battery. In- •tractions complete. 2Sc. Catalogue Free. Rep. resentativea wanted. STEIN METZ WIRELESS MFG. CO.. EASTEND, P1T1SBURCH, PA OLD MONEY WANTED — $2.00 to $500.00 EACH paid (or hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave. 83, Le Roy, N. Y. HAVE YOU SEEN IT? My unusual, fully 11- Uutratcd radio catalog is complete. Savea you money. N. E. Ristcy, Spring Grove, Minn. YOUR HOROSCOPE, business, changes, social, matrimonial prospects. Send birthdate and Tea Cents (stamps) for remarkable test reading. ZANYA, 302 ], West 105th St., N. Y. EXCHANGE JOLLY, INTERESTING LET~ TERS through our club. Stamp appreciated. Betty Lee, Inc., 4254 Broadway, New York City. RADIO FANSi Have you read of the won- derful new all- wave Radio Frequency Amplifier invented by Doctor Miller of the Naval Radio Research Laboratory, Bureau of Standards, Wash- ington, D. C? We manufacture this device under license. May be added to your present set. Riving wonderful results on distant stations, or may be made up into loop receiver sets with extreme range and beautifully clear reception, for home or automobile use. Besides being the beat amplifier on the market, the Miller covers all waves at equal efficiency. Price, 16.50 per •nit. Details free. Coast Radio, Inc., EI Monte, Los Angeles, Calif. "MUSIC composed" to words. Bauer Bros, (formerly of Souse's Band), Oshkosh, Wis. RADIO MAN with two years' experience de- sires position. Herbert, Listerville. New Bruns- wick, Canada. Radio Club Activities in West Virginia THE Delta Radio Club has been organ- ized with the following officers: Neil S. Forman, president; Joseph D'Agostino, secretary ; Randolph Liston, treasurer. It is located at Morgantown, West Virginia, and its call is 8-BQG. The West Virginia University Radio Club is another new one. It is authorized by the University College of Engineering. Call, WHD. The officers are : Arthur Price, E.E., president; Joseph D'Agostino, associate member, I. R. E., secretary. PATENTS Protect your invention today. Write for 1923 Illustrated Book Free. Radio, Electrical, Chemi- cal and Mechanical experts. Over 30 years' ex- perience. A. M. Wilson. Inc. (Radio 3 ARH), 110- 18 Victor Building, Washington, D. C (Successors to business established 1891 by A. M. Wilson.) Manufacturers si Rogers Radio Receivers asm Rogers Receiving Hasanssstcrs. Rogers Radio Company, 5133 Woodwortu Street, Pittsburgh, Pa. EXCHANGE LETTERS with friends everywhere. Pleasant pastime. Information for stamp. Smith, Box 3125, M. Portland, Ore. news amd ooaaip or the otacr lead Mo, for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. M.8S year, (2.00 six months, 8L80 throe sasoths. New Vorfc Star Co.. 1493 Broadway. N. Y. PATENTS— Electrical cases a specialty. Pre- war charges. B. P. Fiahbume, Registered Patent Lawyer, m McGUl Bldg.. Washington. P. C FREE APPARATUS FOR SECURING BUB- SaUPTHMO FOR "RADIO," Write today is* complete hot of premiums and our special sub- scription star. "RADIO," Pacific Bldg., San Francisco, Cel. St% MORE RECEIVING POWER with the Harsha 6 volt, 80 ampere hour radio "A" special storage battery, which is guaranteed for two years. $18.00. Vernier Variable Condensers. 4J plate, $6.00; 21 plate, $5.50: 11 plate, $5.00. Grid leak mounting, 35c. Send money order, but do not add postage or express charge. J. MASCUCH, 74 North 19th St., East Orange, N. J. BOOST RADIO. Wear a pin or button. It shows you are progressive. Designs and esti- mates furnished by official club jewelers. The Rsnkin Co., Radio Dept., 1111-21 Chestnut St, Philadelphia, Pa. LOOK I ALL NECESSARY PARTS to make V. T. Detector Control, including drilled j>anel and wire. Price $3.75. Karnes Radio Shop, Chico, Texas. LOW RADIO PRICES-Write now for free MONTHLY BULLETIN. Gives up-to-date prices on new merchandise. HOLMES ELECTRIC CO., Libertyville, Illinois. M Blessings on 'Em AY blessings be upon the heads of the gentlemen who invented: Phonographs, Player pianos, Radios, Slide-trombones, Clarionets, Fiddles, Singing exercises, And may they always have to lie awake and Hsten to them.— Roy K. Moulton in "The Mail," New York. GIVE A SPIROLA CHRISTMAS ! sad IsCthe vholo family llrtae ts REAL MUSIC all the yesr thrown I Notfilne sdde ss much hi a twe-etaee est high-grass laud maker. SPIROLA* are BETTER LOUD SPEAKERS REAL CABINET TYPE— est lust res usual asm enclosed In a cabinet. Powerful, beautiful, with an INCOMPARABLE TONE. We auks a constats Una — of the hlghnt ckua eonatmstlen throughout, with Use head rubhsd fin lines. 8PIR0LA8 ars and haw always bam Mid under mmsy-batk guarantee ti equal In velum* slid fsr surpass in beauty and tsas any steer us ts twice their price. SPIROLA CONCERT — Ceaiplets with " In place ef Shanes. Fl SPIROLA DUPLEX— Far use with any headcat. Separate eliminating Interference. Finish: eak (00) er aahegany (DM), braaicd $4.85 P uiv ami tans any nnar up n nia inair price. RT — Cempletc with built-in unit and cord, reedy to attach tin rn Finish: eak (CO) er mahogany (CM), bronzed throat. .. X — Fsr Has with any headset. Separate tens chamber ler each threat Satin bleak Reich all oyer, nickeled fitting.. (DB) SPIROLA SIMPLEX — For uaa with Baldwin or ether unit. Oak (SO), and black (SB) nullhea. aarae prleee as DUPLEX. «• ' i -n or peetspld (C. 0. D. II preform)). If declred vs will tend In holiday packing direct to recipient can • -ma your Inctruetleai. DEALERS' We can till holiday ruitl ordcri! L. H. DONNELL MFO. CO., DEPT. B, BOX 70. ANN ARBOR. MICH. $3.85 mahogany <(8M) Supereensitive tested Crystal No busier test necessary. If not satisfactory, return crystal and money will be refunded with mailing charges. Mounted, 50c.; unmounted, 45c Special Prices to dealers. Wm. Hafner, 726 New St., Camden, New Jersey. * DIALS, 3- inch, genuine hard rubber, raised or depressed scale, white or gilt lettering. Drilled for <A and % inch shafts. 60c. each, 3 for S1.S0. postpaid. No sumps. RADIO SALES CO., Box 1144, Bethlehem, Pa. MILLER AUDIO FREQUENCY transformer eliminates howling. Entirely satisfactory on three stages. Price $5.00 postpaid anywhere in U. S. RADIO SALES CO.. Box 1144, Bethlehem, Pa. MEN WANTED for detective wsrk. Experi- ence unnecessary. Write for details exylaia- ing guaranteed position. J. GANOR, former Gov't Detective, St. Louis, Mo. EDISON storage "B" Battery Elements. 5c per pair. 18 will make one 22.5 volt battery. Oilman's Battery Shop, Chelsea Square, Chelsea, Mass. GET A IN* MILE RANGE RADIO XMAS PRESENT FOR $32 -SS complete with tube, phones, "B" Battery. $16.50 down, balance monthly. D. 4 R. Radio Supply Co., Fort Dodge, Iowa. INSTANT BATTERY CHARGER I Radio set* demand it. Manufacture at home on royalty. Big Profits. Gold Seal Chemical Compear, Syracuse, New York. 1430 Broadway. New Yerk. WE PASS samplea or circulars, lc each, la houses direct. Lady Canvassers. We mail row circulars, 25c. a hundred. Guaranteed nance of our mail order customers. 75,000 up-to-date lists, 12.00 thousand; 7.000 $10.00. C H. Dsns 4 Sen News Agency and Mail Order Distributor!, 614 W. Jefferson, Greenfield, Ohio. VACUUM TUBES repaired reasonably. Satis- faction guaranteed or cost nothing. Vacuum Electr, 10J, 1621 Derr, Toledo, O. ARNOLD NAVY MODEL LOOSE COUPLER Back to Pre-War Price The most consistent piece of apparatus on which to hear the Radio Telephone (Broadcasting) range from 200 to 1,000 meters "WITHOUT DISTORTION." It Is A COMPLETE TUNER. Only a min- eral detector or Audlon Detector re- quired. Send In your order today. Im- mediate ahlpment promised or call and hear one and take It away with you. A 3c stamp will bring my literature showing; my complete line. SPECIAL fete built to Order, Repaired or Rewired. Accessories for Sale. Baldwin Phones Repaired. New Diaphragms Put On. J. F. ARNOLD S289 THIRD AVE, N. Y. CITY Established 1910 (Near lttHh Street) WE NEED RADIO WORLD, dated April ■ and August 5. If you have copies you doa't in- quire, mail to this office and current issaes sfl be sent you for them. RADIO WORLD, 1* Broadway, New York. Digitized by Google-

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RADIO WORLD Remote Control a Future Use of Radio AS we listen In on our little receiving set* we think that radio is a great thing, and one deserving of much atten- tion. But yet, do we ever consider the many other uses that radio waves may be put to beside that of broadcasting intelli- gence and music? Remote control of mechanism is also possible with these very same waves, says "The Globe," New York. With the development of amplifiers there has come the increasing possibility of using radio to control the operation of any machinery or motion at a distance, by use of a relay or switch connected to special radio receiving apparatus. In or- der to accomplish this, signals are trans- mitted by radio, and are received by a receiving station employing a very sensi- tive ampliger and specially designed relay device. This relay is then connected to such mechanism as it is desired to operate wat the receiving station. Such mechan- ism can be an electric light, an electric bell, the control lever of an airplane, the switch of an electric power line, or, in fact, most any mechanical or electrical device. A disadvantage of radio control is that the receiving apparatus must be in continuous operation, with consequent consumption of power from the batteries or generator which supplies current to the receiving set. For certain purposes, however, this is not too great an expense to keep the use of distant control by radio from being feasible. The use of radio in this way is being considered by a number of electric power companies for operating switches at distant power plants or stations. At one of the recent manoevres of our fleet a battleship without a soul aboard, equipped entirely for radio control, was sent out to sea, and acted as an effective moving target for our gunners on other ships. The Voice Amplifier AS it is becoming popular to broadcast events which take place miles away from the broadcasting station proper, it has become necessary to make use of a "voice amplifier." This device enables the reproduction at the station of sounds picked up a great distance away, without the loss of clearness or intensity at the broadcasting transmitter. Subscribe for RADIO WORLD. $6.00 a year, $3.00 six months, $150 three months. Attention, Newsdealers Yon ■boald keep a mood (apply ol back Boaters oi RADIO WORLD oa hand all the Haw. It baa bees the experience ol manj dealcn that a parchaaer ol RADIO WORLD lor the Grit thaw via ahaoet immediately want the back aaatbero, aoma ol which are already out ol print ana aoaae oi which are dificah to eet. THE rVBUSUKR WILL FURNISH BACK NUMBERS TO DEALERS DIRECT OR THROUGH THE AMERICAN NEWS CO. AND ITS BRANCHES. Dealers • ho aid hold their uneold copies lor « roseonable leaath ol time. RADIO WORLD oj October 28 contained a lull pate ol contents oi back aambers to that date. 15 cents per copy ; say seven numbers lor $1.00. RADIO WORLD. MB Broadway, New York. COMPLETE YOUR FILE OF RADIO WORLD CoptM of Radio World No. 1 If yon dtd not get a copy of Radio World No. 1 Bond a* SS.M and wsj will toad yea the paper for ono year, aad start it with oar first isBoe, which will bo mailed yon as soon as after receipt of order. «**■» Those Broken and Burned-Out VACUUM TUBES CAN BE REPAIRED and Guaranteed Too! If your dealer does not know, tend direct to us. Harvard Radio Laboratories 165 HIGH STREET BOSTON, MASS. Tube* rata road Parcal Post, COD. AMERICAN RADIO-STORES SPECIAL SPECIAL TUBE SET I W. D. II . I W. O. M Ta I SrM Leak On I "B" Bettor. »•» I "A" Battery. sVy MB I Varlmeslsr I "II" Plato Osoesessr Win tar Heat Oe Free no55 CRYSTAL SET S4.SS BeaMt Ml*! Ti . OaB. IMS Crystal Betoetor ealat • KA tarter fil' Aerial Win. t li (aeuik). THE "SKINDERVICKEN" BUTTON •sea ey stone. Every Bade Fee waste see. AaslrSw year tleeah We km teem. Vee «HI neat see neat eeey **** ** 95c DEPENDABLE MERCHANDISE AT REDUCED PRICES SETS 1225 OS WlreleB) Ssselalty— Crystal Aedleo, IS* to S.StS —tore. Bar tiySl Basy' Lewies' ' Coital Aerial Wire Iseetotors eoe IIS.lt PsUk.enee. awMi -Cea tt.st I.SS IIS PHONES 11.00 13.00 12. 0» S.IO ti.s* i.so .ts I. OS 1.00 1.25 Waiters Eiectrk) Be. 300- W. KellHi Pkeese Acta RHEOSTATS Besel . Raosrts Betlee Perwlsls Base. 17.01 IS.SS UII i.se 7.00 4.0S M:.i .75 .7S .40 .Si VARIOMETERS Ss.oo Beets, Verleaeton S.00 Patoa-Sreta Verleaeton S.0S BeMele Varleaeten Otaen at Lew es Bee Bellar AMPLIFYING TRANSFORMERS tS.SS BeMele Cseetor Sever Tree IS.SS • i0 Ease Verla-Ceeetar 4.1* S.00 Battel Varte- C»e»ler I S* LOUD SPEAKERS S3 00 Beeerel Basle $1.71 7 00 Jaffarate 4 IS 0.10 MerMt BaSle Fnseeoty |.so S.oe Balewle BeaU Fneeeety I SO SPECIAL Feralet. seea* |].M Paa.it erintS to letorSaniisi. Baaiaaan' Prartlw Ksyt 11.30 W. D II Sestets. .71 Alto Heesne* et Otaer Baa* Bereelet Tee Beetereet to Ust THESE PRICKS DO NOT DtCLlDE POSTAGE. AMERICAN ELECTRO TECH. (EstablltlMcl 19 IS) 235 FULTON ST. and 1987 BROADWAY (near 67th St) Be a National Radio Week Booster

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RADIO WORLD \ 'Tfje 111155 TnQTl 1dd\s info Space , ff and l^no ujs rtjete is na limit- ha dimension. >-r* said XjuanjfRu , ■ TnB urise J^adiaish Drives trje a/satest dis ranees Culttr" 01 S\ TT> V /• <^rebBJKECElVEl/. ALONG RECORD of unequalled performance has won for the Grebe Receiver the unqualified en- dorsement of all good dealers. "Musings of Doctor Mu" — the story of the development of the Per- fect Receiver, free upon request. A. H. GREBE <Sl CO. INCORPORATED RICHMOND HILL, N. Y. Licensed under Armstrong U. S. Pat. No. 1113149

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New DX Records Inside December 16 15c.aCopy$6.00aYear A (Trad* Mark) ILLUSTRATED. W KL How Clemenceau's Speeches Were Amplified from a Truck del «r Herbert To injur, the vast audience that wished to hear Georges Clemenceau, "the Tiger of France," the Western Electric Company used a radio speech- amplifier mounted on an automobile truck stationed outside the hall where the speech was delivered. The photograph at the left shows the amplifying truck; at right, D. C. McGalliard operating the amplifier. low to Put a Vernier Attachment On Your Condensers— See Page 4 TmNAi. RAnrn WFFftr tjumm?i? nur mkyt ufhrvt

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RADIO WORLD A Gift For YOUR Entire Family 77* is Is a Radio Christmas / The De Luxe U. S. Navy Type Radio Receiver Give the BEST This De Luxe U. S. Navy Type Radio Receiver must not be confused with instruments selling .for from $200 to $300. Highly selective. Will pick up messages, music, lectures, etc., that lower-priced instruments will not hear. For Immediate Christmas Delivery $ 595 List Price Write for special club or trade' discounts CHARLES R. ABLETT CO. 199 Fulton St, NEW YORK CITY if THIS receiver h equipped with blading posts which are nor- mally short circuited lor 300 to 6800 meters by which wave lengths np to 23,000 meters may be received by the attachment of loading coils. Capacities of proper loading coils for above are : Primary SO; Secondary 50; Tickler 30 millihenries. While the receiver is pro- vided with a "standby" or untuned circuit, it also has an unusual degree of selec- tivity. Although primarily designed for the more ad- vanced fields of Radio work, or the laboratory, the simplicity of arrange- ment and beauty of finish make it unusually desirable for the radio club or tor the individual who desires the finest equipment ob- tainable for his home or office. In the receiver, Bakelite tubes, threaded, provide the forms on which inductance coils of high frequency cable are bank- wound. After assembling, the coils are impregnated with an insulating com- pound, in vacuum, and thoroughly baked. The in- ductance switch controls a mechanism whereby the different sections may be connected, completely dis- connected and opened, or completely disconnected and individually short cir- cuited. This arrangement is important for, by it, each coil has a natural period when connected which is less than the shortest wave length in the receiver's range. The reception of parasitic signals _ is over- come, the absorption of de- sired signals by the coils is minimized, more energy is forced to the detector and on all wave lengths the interference is reduced. UlCjlllZGQ Dy

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VOLUME TWO OF RADIO WORLD [Entered as second-clast matter, March X, ISM, at the Peat Office at New York. N. Y., under the act af March 3, 1879.1 A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Tdepbosw: Bryant 4796. VoL II, No. 12. Whole No. 38 December 16, 1922 15c per copy, $6.00 a year They Not Only Pump Air to Deep-Sea Divers But Keep in Touch with Them by Radio When a man gem down hit* the ocean's depths, today, he doea also talha to the ahip above by radio. Thla photograph ahowa tiaaoiallllin eat that makes ft paaolhlo to keep m tench with h Me usee • waterproof set strapped to hie bask. Thla est la everyday affair, the ! have to worry that the telephone cable will break. He gets hie instruct! oas sad el the pumps that supply the diver with fresh afar and, alongside of It, the by radio, The aerial for the diver Is an insulated wire strung Inside hie < to the wave length of the ship afloat. While submarine iilnlm Is between the diver end ship la a recent improvement. TO the uninitated, it is a con- stant source of wonder and ever increasing mys- tery as to how deep-sea divers re- ceive signals while under water. Both the United States govern- ment and private individuals have made experiments which prove that radio waves transverse water with the same ease as they transverse the air. It is no mystery, then, to understand that if you use a very well-insulated wire for an aerial communication may be carried on through the medium of water. In a series of tests made by government experts, it was established that a submarine could carry on communi- cation with land stations and air- planes while running fully sub- merged. A very interesting experi- ment may be tried out by experi- menters who would like to prove this fact. Bury a well-insulated wire in -some nearby fairly large body of water, using it as an aerial, and connect up your apparatus in the ordinary way, using the same body of water as a ground. Then use this aerial to prove that it is no different from the aerial you take hours to string up over your roof. Government experts claim that bet- ter reception of signals is accom- plished in some cases than when a regular aerial is used. In the tropics there is a noticeable decrease in at- mospheric disturbances when the submerged antennae is used. The outcome of several experiments that are being carried on at the present time will be published in Radio World as soon as they are made public, and some startling news may be expected. The French Govern- ment also is carrying on a similar series of tests along the same idea. It is claimed that France has some- thing of vast importance in connec- tion with grounds, which informa- tion will be known soon. Digitized by Google

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4 RADIO WORLD How to Put a Vernier Attachment on Your Condensers By Ortherus Gordon RIGHT on the heels of the need for sharp adjustment of radio instruments have come "vernier" attachments for almost everything. Vernier is not a Scotch word, meaning "close"; but the last name of a Frenchman — Pierre Vernier — who first felt the maddening desire for a scale which would measure the fractional parts of -a whole unit He invented what is now known as the "vernier scale." His idea was hailed as a boon by scientists. At the present day a scientific instrument which has any leaning toward accuracy cannot afford to be without a vernier attach- ment. In fact, some of the verniers are so minute that they carry a magni- fying glass around with them for con- venience in reading ; otherwise the fine points would be lost to the naked eye. Applied to radio apparatus the vernier idea has given manufacturers a chance to put out some pretty slick articles, especially in the way of variable condensers. But woe to the radio amateur who already has variable condensers without Pierre Vernier's neat device to make them discriminat- ing and set them off ! Scrapping per- fectly good variables is out of the ques- tion— even if in favor of such a desir- able feature as the vernier. There is only one attitude the un- lucky amateur can take — look glum and stand it, unless he sees some merit in the idea that one radio amateur worked out for the benefit of his own little variable condensers. He wanted a vernier control on his condensers because he knew what close tuning meant. He couldn't afford, however, to buy new instruments. Therefore, being a radio amateur, his thoughts naturally turned toward home con- struction, and they weren't bent more than a minute in that direction before he decided that what he wanted was not construction, but reconstruction. In other words, instead of building a whole new condenser he decided to build only the vernier attachment and then find some way to add it to his existing instrument. No sooner said and fretted about than, shortly afterwards, several ways were outlined in which the great idea could be worked out. A little later came definite plans. There it was— the neatest little vernier attachment you ever saw, movable and everything, which could be added to a standard Flfim 3— Am— My o» tha mkr nmit ana thm standard eond— % Tha phanagnph . disc la oat pat am until eaaaslstsd laali H- BMBt la mauatad mm paaaL. condenser without danger of putting it 6ut of commission! This article, illustrated by the sketches, tells" how the amateur did it. What he wanted was an extra mov- able blade — not one that turned with the Others, but an independent affair, which would swing off by itself when he so desired. He also wanted some- thing that could be operated from the panel and that wouldn't be a disgrace to his bright 3-inch dial. To fill these requirements he collected, on his workshop bench, an old phonograph - record, one fiber washer, a piece of brass tubing and two new condenser blades — one for the stator and the other for the rotor. The inside diameter of the brass tubing was slightly larger than the outside diameter of the rotor shaft, so that the tubing would fit snugly over it With these simple parts he proceeded to make the "vernier unit." When it was finished it looked like Figure 1 . The phonograph-record had MDonnniiiiM] Pleura 2— W rhracnt aa fittad to tha tutor of tha of tha standard condcBsar, alas tha chaafaa to accommodate tna naw unit.

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RADIO WORLD 5 Broadcasting the Yale-Harvard Game (C Underwood a Underwood, N. Y .) The photograph tells the itorr. Im the background ia the soundproof booth which nirnlnnhia Yala BowL b the right foreground, an the overcoat of a newspaper reporter, la reproducer, the device by which the cheere could he heard so plainly. Man with reproducers attached w> their overcoats wars acattered about the huge bowl so that any section that started shears ar songs could be immediately heard by Just plugging hi at the booth. booth the sounds wars transmitted by special wire to WEAF. {Continued from preceding page) been cut down until it was half an inch larger all around than the dial. The hole in its center had been enlarged and the threaded end of the brass tubing fitted snugly into it. On die other end of the brass tubing, fastened to it by pins riveted oner, was a condenser blade. The whole unit, plus a fiber washer, as shown, was slid over the shaft of the rotor so that the new blade fittted closely against the shoulder of the shaft, as shown in the upper part of Figure 2. The "vernier unit" is drawn in with dotted lines. The shoulder mentioned (S) should be filed, or machined, so that it is the same thickness as the washers which separate the blades, otherwise the corresponding spaces in the stator will have to be widened so that the vernier blade will not touch any of the station- ary blades. In preparing the stator so that it will accommodate the extra "unit" it was only necessary to add a blade, as in- dicated by the dotted line in the lower part of Figure 2. Mr. Amateur also found it necessary to enlarge the fiber bushing in the cover of the stator so that it would take the increased diameter of the brass tubing. This is also indicated in Figure 2. The vernier unit made and the stator prepared, everything was ready for assembling. Figure 3 gives an idea of how the condenser was put together again. A fiber washer, just one-half Figure 4-How the disc of the vernier attachment and the dial of the regular instrument look on the panel. The disc and the dial are not put on untO tha instrument is sat up on the panel. as thick as the space washers used in the instrument, must be inserted be- tween the vernier blade and the inside of the stator cover, as shown in the sketch. The disc and the dial are not put on until the instrument is set up on the panel. Then both disc and dial go on outside, so that it appears as in Figure 4. The reconstructed instrument is a beauty. The pins, which are sunk into the phonograph disc, help in the adjustment because, actuated by them, the vernier plate may be turned by the idle fingers while the other movable plates are being turned by the thumb and forefingers. No dimensions are given in this article. It is the idea itself that is the more important. Short Waves By John Kent The Potentiometer's Work THE potentiometer produces fine variations of voltage by means of a sliding contact which plays over a fixed resistance through which a constant current flows and which has a certain definite resistance. A clear idea of the potentiometer may be had by taking two circuits, an in- put and an output, going to and coming from the resistance. The input, which may be a source of emf (electromotive force), goes to the ends of the resistance. The output is taken from one end of the po- tentiometer and the sliding contact. Ohm's law states that E — I x R (Voltage equals amperage .times re- sistance), and since the input circuit is through the whole resistance, I remains constant. The part of the resistance between the variable con- tact and the end from which the out- ut circuit is taken is variable; ence, since I is constant, in order to # maintain the equality of the equa- tion, voltage equals amperage times resistance. If the resistance changes then the voltage must change in the same direction by a proportional amount. * * * Try This Method MANY amateurs like tb hook up their own sets. They buy a lot of apparatus, a panel and other de- vices, then they solder up all the connections and are surprised and disappointed when they don't get the results they expect. Try this: Instead of going ahead and hooking up permanently at once, use some old copper wire and experiment. Then if you don't get satisfactory results, you can change your con- nections without feeling that you have been stung. * * * The Sensitive Spot IN operating a crystal detector, it often occurs that a sensitive spot usually is lost with the least jar or shaking of the table. To keep a proper balance, adjust your crystal detector to the sensitive spot of re- ception. Drop some melted wax from the top of a battery onto the covering of the crystal detector. This means that the sensitive spot of the crystal must be covered. The detector will then be grease proof and cannot be knocked out of ad- WgWby GOOgk

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1XM — A Station That Claims High Radio Honors By C. White, Consulting Engineer THE Massachusetts Institute o£ Technology's radio station 1XM, operated by the M. I. T. Radio Society, is one of the most remark- able amateur radio installations in the United States. Its unique design and high operating-efficiency place it in a class by itself. Signals transmitted by this station have been heard many times in Honolulu and very often in Great Britain and Europe. Such re- sults are made possible only by the most careful technical attention to small-design problems, which actually determine the success of a station. Figure 1 illustrates the general ar- rangement of the sending and receiv- Figure 2 — Showing the counterpoise which is used for a ground. The low capacity of this system cause* a very sharp wave to be radiated. ing apparatus. On the extreme left is shown a 200- watt quenched-spark transmitter used only as an emergency set, and which has a normal working range of 500 miles. Next to it is a Signal Corps type of radiophone trans- mitter and receiver. This outfit is often used for reception. At times, it is employed to broadcast local phone- messages, but its use in this particular field is limited by the local broadcast- ing stations. The next group of ap- paratus is an Amrad short-wave re- ceiver, using radio- and audio-fre- quency amplification. The switch- board panel is unique in operation. It effectively controls the motor-gener- ators and the connections for modula- tion on the tube transmitter shown on the right. This transmitter has a normal work- ing range from 3,000 to 6,000 miles! It is creating much attention among radio amateurs. This feat of opera- tion is really worthy of nation-wide comment, since with only four 50-watt tubes an amateur station can send at a range equal to that of a commercial station using many times the power. For straight C-W, 1000 volts is im- pressed on the plate circuit of the tubes and the modulation is accomplished by a key through relays on the grid cir- cuit. The carrying power of the 200- meter wave is enormous. The 1000 volts, D-C, for the plate supply, is obtained by a mercury arc rectifier. For work at shorter ranges, the plate- supply voltage is taken directly from the 500-cycle motor-generator. By this method, a characteristic pitch note is produced. Those amateurs who have copied 1XM signals will testify as to the quality of this note. Figure 3 shows a close-up of the transmitter showing the control panel, key, and relays, tubes, meters, trans- formers and filters (under table), tun- Figure 3 — Close-up of the transmitter showing the control panel, key, relays, tubes, meters, transformers and tuning coil, also the mercury arc-rectifier. The radiating equipment T-rr'rtT of four wire cage-aerials one hundred feet long. Digitized by VjOOglC

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RADIO WORLD 7 Try This New Tuning- Coil Hook-up IN these days, when all you hear talked about in radio is superregeneration, heterodyne, and two-variometer circuits, other elements are overlooked. If one refers to a tuning coil, he is looked at in surprise and, maybe, disgust. But if the. average amateur were to be told that he could get regenera- tion on a three-slide tuning coil, he would turn from disgust to wonder, However, this is just what I am going to try to prove to you in this hook-up. For the person who is inclined to experiment, or the radioist who would like to have a bulb set but is hindered by lack of ready funds, the little circuit published herewith will prove a pleasant surprise. It is not without Its merits. Of course, the results will not be equal to those of a three-unit regenerative set, yet it is surprising what may be accom- plished with it after one has become accustomed to its manipulation. By Robert L. Dougherty Schematic diagram of regenerative est. If you happan to hava a rart- abb condenier around, you can Inaart it m tfca aerial load. Thla will aaako tfca aat mora eelec- uVe, although It It not abaalutely necessary for propar manipulation. The new W-D 11 worka admirably with thla hook-up. It need* only a ■ingle dry-call to operate at its higheet efficiency. Long diatancea have bean worked with thla Ht See what you can da with it— you aceptice and The apparatus needed is a three- slide tuner, a bulb, socket, rheostat, A and B batteries, and phones. When hooked up according to the illustration, and slider No. 1 is moved back and forth — that is, the one controlling the wave length — a sound similar to the "frying noise" in a regular regenerative set will be heard. If this noise is not heard, you will have to adjust slider No. 3. The best position for this slider will generally be found about three fourths of the way along the coil in approximately the same position as that accompanied in the illustration. Slider No. 2 should be used after the signals are heard; but it will be found that it will work best when kept below the position of slider No. 3.' After slider No. 3 has been adjusted, it will not be necessary to move it, as all the tuning is now done with Nos. 1 and 2. A variable grid leak is of great assistance in con- nection with this hookup. Radio Relays to Remember By George W. May, R. E. Topography of Country Effects Range ONE important element in radio is "the lay of the land"— the topography of the country. It has a great deal to do with the effective range of both the receiving and the transmitting set. Outfits that are exactly alike in their make-up and located only a few hundred feet away, have been known to have widely different ranges. Many times this has been experienced by the average radioman and, some- times, found hard to explain; for conditions seem to be apparently the same, but close observations will bring to light some little factors that tend to reduce or increase the range of the set. Many advocates of the open air who take their receiving sets with them, especially when situated in a depression between mountains, may be disappointed when they get poor results or even no results. It is a known fact that radio waves do not descend to any extent into valleys {Continued from preceding Page) ing coil, and the mercury arc-rectifier. The radiating equipment consists of four wire cage-aerials 100 feet long, the upper end of the antennae is at- tached to a 150-foot stack. A counter- poise is used for a ground, and the low capacity of this system causes a very sharp wave to be radiated. Figure 3 also shows the general ap- pearance of the system and gives a fair conception of the magnitude. The efficiency of the cage-type aerial, as proved by actual tests at this station is very high. Aside from the ordinary routine re- lay of messages, the society conducts an active research and testing cam- paign. Many of the experiments car- ried out at this station are of an ex- treme technical nature. The result of tireless effort has been the development of many new and unique hook-ups. Figure 3 gives a general idea of the nature of the experimental bench. The ease with which any voltage, A-C or D-C, may be obtained makes it quite easy to conduct any type of test work with the minimum amount of wiring. By diligent application, due to well-founded technical training and ex- perience, this station is maintained and operated at maximum efficiency. New apparatus is constantly being added. An 8-tube superheterodyne was con- templated recently. surrounded by high, steep moun- tains. If there is a considerable space, this does not hold true; for in this case -the radio waves follow more readily the exact contour of the earth's surface. When the mountains are close together, the waves seem to jump from peak to peak rather than descend between them. If you are in the mountains, try and erect your aerial at as high a point as possible. Maybe you happen to be in a location where your signals are poor. Dry, arid land surrounding a radio station also tends to reduce its range, while ex- panses of water will tend to increase the range. Surroundings of metal often decrease the range. High, steel buildings absorb waves. When- ever you are surrounded by build- ings, it is well to suspend your aerial as high as possible. * * * Locating the Aerial WITH the best of conditions, the aerial can be run from one end to the other of the house, in- side as well as on the roof, although the outside aerial is recommended as superior to any other. The greater the height at which it can be suspended has some effect on the ability of catching wave trains or signals. We must remember that radio waves go through everything. The plaster on the wal's of a house have no effect on radio waves and offer no obstruction to them what- soej^ifeed by \J\J

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8 RADIO WORLD Secretary Denby Rates Radio High in Government Work Naval Service Earns Over Two Million Dollars in Six Years. Aids Merchant Marine, Press, and Governmental Service WASHINGTON, D. C — Ra- dio in the United States Navy, taken solely as a busi- ness proposition, is a money maker for the government. During the past six years, $2,222,956 has been de- posited in the United States Treas- ury out of a far greater amount col- lected for the transmission of com- mercial radio messages. The col- lections during the last fiscal year totaled $627,904, out of which $369,- 735 was deposited in the treasury, Secretary Edwin Denby states in his annual report. Collections in the year 1922-23 showed a falling off of such receipts due to the fact that many merchant ships were laid up, while savings also decreased because all governmental departments were endeavoring to economize in com- munication expenses. Governmental traffic handled by Naval Radio stations, other than Naval communications, would have cost $1,080,800 at commercial rates and was less than a third of the traffic handled the preceding year. By Carl H. Butman This amount added to the commer- cial receipts would have brought the year's business in Naval radio traf- fic to $1,708704 in receipts and sav- ings. When it is considered that the Navy in no way competes with commercial stations, but handles messages only where and when commercial stations are not avail- able, the- aid rendered in this auxili- ary radio work is better appreciated. For the Merchant Marine alone the Naval Communication Service handled 3,749,483 words during the past year and forwarded press mat- ter to the number of 1,012,279 words. As a new departure in the inter- ests of economy, an attempt was made, last summer, to employ the Naval radio circuits exclusively for transcontinental traffic, but static in- terfered in May and June so severely that delays were encountered. Fair- ly satisfactory results were obtained from transpacific circuits, but the completion of the new high-powered set at Guam is required for efficiency in that circuit. Headquarters of the Roughing It By Radio by Uwnnca B. Hinckley) European communication service were established at Paris, and of the Asiatic Division at Cavite. In Eu- rope, the Naval Service co-operated with the American Relief Admin- istration and the European Chile Fund. During the Limitation of Arms Conference, two Pacific cir- cuits were set up for the Japanese Government, one of which has been continued for business purposes be- tween the United States and Japanese Governments. A service rendered by the Navy, but little known, is in receiving SOS calls, which in the winter av- erage thirty a month on the coast between Maine and Cape Hatteras. Sixteen of the Navy's shore radio- stations were closed as "not neces- sary in accordance with the approved national policies," during the past twelve months. Twelve of the fifty- six radio compass stations, operated by the Navy free for the benefit of merchant vessels lost in fog or with- out efficient compasses, may have to be eliminated due to lack of per- sonnel, it is stated by Secretary Denby. He explains that the fur- nishing of compass bearings to ves- sels off the Coasts and on the Great Lakes is of great value to shipping interests. Some stations handle as many as fifty calls a day in bad weather. At present these stations operate on an 800-meter wave and are ef- ficient for a range up to 150 miles, but a new long-wave radio compass is being developed which will op- erate on waves between 500 and 2,500 meters. This would increase the distance of audibility up to about 1,000 miles. In addition, it is ex- pected that this instrument will have great value in time of war. A new Naval radio-set for use in spotting gun fire was tested out at the Anacostia Naval Air Station re- cently. After a fifteen-hour flight- test with the manufacturer's model of the SE-1375 spotting plane set, the model was returned to the manu- facturers as a guide for production of a number of sets. It is reported to have stood up well under the test and, with the exception of a few minor changes, to have given very satisfactory results. Digitized by Google

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RADIO WOULD 9 Fleam L Haw tfca Accurate Tuning with the Capacity Switch By Donald Van JVyck THE desire to place all con- trolling elements of a cabi- net radio-receiving set on the outside of the panel has brought into general use the series parallel- switch. The suggestion that addi- tional instruments be provided for the receiving set in order to in- crease selectivity is usually accom- in series with either the ground or panied by groans from the man who the antenna lead. When it is in this pays the bills. But when incor- position, it enables the* desired fine porated in the outfit they may be tuning, but does so by simultaneous- rearranged to advantage. ly shortening the natural period of The rearrangement consists chief- the antenna system comprising an- Iv in reconnecting the primary con- tenna and ground leads and the pri- denser so that its sphere of useful- mary inductance, ness is considerably increased. By while this reducing is permissible the shifting of a few wires and the with the antenna and variable con- addition of a single-switch knob, densers in use, it nevertheless low- ers the effective tuning of the set as a whole. The series variable con- denser makes the tuning of the re- ceiving set more difficult. With the variable condenser placed in series with the primary inductance, tuning may be said to be more complex because the con- denser unit must be set within cer- tain limits depending on the wave length to be received. This with the primary fine and coarse switches makes three controls which must be set in correct relation to one an- other. When the primary condenser is connected in parallel to the pri- mary coil the condenser dial may remain at zero during the prelimi- nary tuning with the switches, and, later, may be utilized as a correc- tive tuning measure. This latter arrangement also increases the wave length to which apparatus may be tuned. There is no doubt that both series and parallel switches have their ad- vantage, the former for the lower and the latter for the longer wave- lengths possible with each particu- lar outfit. This series parallel- switch then answers the purpose. This switch has puzzled many radio amateurs who are puzzled when they realize its complications. The double switch-arm has also served to confuse the casual inspector be- cause he labors under the impres- sion that it is necessary to bring flexible leads to each of these metal strips or else he thought that both arms were separate pieces of sheet metal. Yet the series parallel- switch is nothing more than two separate contact arms. It is simpler to _ construct your own capacity switch than to go out and purchase one. The parts of a capacity the goal is achieved. The effect on the radio enthusiast when an- other switch is added depends en- tirely on his status in the radio field. The newcomer who scarcely knows the controls feels that he never will be able to tune in the set property. The amateur out in the country where open space is not at a pre- mium generally erects an aerial of 200 feet or more. No doubt he be- lieves that a long aerial will pro- duce signals of greater strength; but he fails to consider that radio- phone broadcasting, in which he is most interested, is sent on a wave of 360 or 400 meters, whereas his aerial has a fundamental wave- length of, maybe, 450 meters or more, or is probably very short. With this in view, the only pos- sible move is to insert some capacity switch and capacity in series, or parallel, with the aerial. The aerial is like a huge conductor with the earth as the other conductor and the air between as an insulator, or dielectric. Thus, by placing a con- denser in series with the aerial, it will produce an effect similar to two • condensers in series. The primary condenser of radio- receiving sets is usually connected for m , •Bal switch consist of spring sheet-brass, a switch knob, and 8 contact points. The knob may be made at home from a piece of hard wood or hard rubber, or it may be made from a large-size thread spool sawed radial- ly in half. Two contact arms are cut from the sheet brass in the shape shown. The distance from end to end may not exceed 3 inches, and may be less, depending on the amount of available space. From each end, bend the strip at right angles about l/i of an inch from the end. The two metal arms are screwed to the knob on the large, or under, side by small wood screws. The spacing between the two blades is such that there is at least % of an inch to sep- arate the two inside edges, and that the cut-out portions at the center may not touch the machine screw which holds the knob in place. The eight contact points for the switch are placed four on each side of the center along the arc traversed by the ends of the switch arms. The spacing between the points is de- termined by the switch blades and should be such that the blades rest squarely upon the faces of the con- tacts in each position. The contact points should be neatly placed with reference to the center line of the switch knob so that the appearance of the panel may be enhanced rather than spoiled. The accom- panying diagram shows the wiring circuit of the capacity switch. The condenser for this purpose should be about 43 plates, although a smaller size will do. In general, the switch is placed in the series position for tuning in short wave-lengths and in parallel when tuning in the longer wave- lengths. Usually this switch is used with the honeycomb type receivers, although it may be used with most any type set made to-day.

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks H OW are ducedf electric currents pro- Electric currents are pro- duced in several ways, the two most important being by electromagnetic induction (magneto and dynamo), and by chemical action. Electric currents are moving electrons. These electrons move along a wire, thus pro- ducing the current with which we are most familiar. They may also move Figure 2— The sum of the currants passing through a. b, and c is equal to the sum of too currents passing through d and a. Each sum is equal to the current passing through any part e» the single wire, as at g. n notes II- Tfrms. the circuit, unattached through space from one point j|p another. This is what happens when a flash of lightning occurs. It is what occurs in the X-ray bulb and in vacuum tubes used in radiotelegraphy. They may move also through a liquid or gas. This is what happens when we use an electric current to electro- plate objects — as, for instance, silver- plating spoons. * * * What has a circuit to do with con- ductors? A circuit is a number of conductors arranged so that they are connected electrically. A current of electricity . will flow through a circuit when some source of electric current is attached to the circuit. When a current is flow- ing in a circuit the current is of equal strength in all parts of the circuit, pro- vided the circuit consists of only one path. * * * Will the current be the same when flowing through the circuit, as shown in Figure 1 ? The current going through the re- sistance — R — the current going through the telephone receiver, and the current going through the telephone Figure 1— Diagram of electric circuit ■nee, telephones, and transmitter in The elm trie currant Is equal in transmitter are equal. If the circuit is divided then the sum of the currents passing through the divisions are equal. * * * How are the currents in Figure 2 divided? The sum of the currents passing through A, B and C are equal to the sum of the currents passing through D and E. Each sum, of course, is equal to the current passing through any part of the single wire, as at G. * * *. Will an electric current produce magnetism? A current is recognized by the effect it produces. An electric current will cause magnetism, give rise to heat, cause chemical action, and may be made to operate by using the magnetic effect. * * * What have we learned? We have learned that magnetism is produced by an electric current ; that a moving electron is surrounded by a magnetic field ; that the magnetic field is made up of magnetic lines of force ; that the direction of the magnetic lines of force is the direction along which the north pole of the magnet is urged. * * * What is the magnetic circuit? The magnetic circuit is the path which the magnetic lines of force fol- low in going from the north to the south pole of the magnet. It has been found that iron is the only perfect con- ductor of these magnetic lines of force. * * * What does iron contain? Iron is said to have permeability be- How to Treat Phones By John Kent IF the owners of receiving sets would realize what delicate instruments the headphones are, we wouldn't hear so many com- plaints that they are not getting as good results as they did the first few weeks their set was in operation. You wouldn't expect your ears to be as perfect as they are if you gave them half the abuse that the average headphone gets during its life. Here are some of the things you shouldn't do to a pair of phones : Don't open the phones (take off the ear caps), or let anybody else do so unless you know just what you are about. Don't tap on the diaphragms. They are easily bent and dented. Don't drop them. They may not break ; but any jar lessens the mag- netism in the permanent magnets, thereby lessening their sensitiveness. Don't pull the phones out by the cord. It is only tinsel. Don't set them in a place where they are liable to get damp or wet. DON'T TEST BATTERIES with a pair of good phones. You are liable to burn them out. Most phones are wound with No. 40 wire which is as fine as a hair and is not meant to stand heavy voltages. Aerial Connections By George W. Mayt R. E. LEAD-IN wires to the receiver may be connected to the end of the aerial or to the center. If connected at the end, it then be- comes what is known as an inverted aerial. If connected at the center of the aerial it becomes a T aerial. This type aerial has a tendency to reduce the wave length approxi- mately one-half that of the inverted L aerial. In case the aerial is con- structed on the roof or outside the house, it is advisable to carefully in- sulate the lead-in wire by running a porcelain tube through the window casing or some other part of the house. This is not absolutely nec- essary in dry weather ; but when the wood gets wet, it becomes a good conductor and may cause trouble as a result of electrical leakage through moisture. cause it will carry lines of force. Dif- ferent kinds of iron have different de- grees of permeability; therefore, cer- tain kinds of iron will carry more mag- netic lines of force than others. Wrought iron has a very large perme- ability. All other substances are poor conductors of magnetic lines of force. Digitized by VjOO^LC

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RADIO WORLD 11 National Radio Week— Dec. 23 to 30 Are You Ready for this Big Event? NEXT WEEK, beginning at dawn on Saturday, December 23, and ending at midnight on Sat- urday, December 30, is National Radio Week. It is the first National Radio Week in the history of this important and wonderful new science. It will be celebrated all over the United States, Can- ada, and Cuba. It comes at a time of the year — Christmas and New Year's — when all the civilized world is alive with gay- ety — filled with the desire to do good and bring cheer to others. And, this year, in no other way can the people give or receive cheer so well as' through radio. It is new 1 You who are dyed-in-the-wool fans know its joys and surprises. Those yet uninitiated are anxious to know — to "listen in." It is estimated that there are six million radio fans in the United States. How many others want to be fans? You can help them to become fans. By doing so, you help radio. What can you do ? you ask. Hold block parties — the good old-fashioned kind — substituting radiophone music for bands. Have radio parties — invite all your friends — and get the "kick" out of the air. If there are any radio "knockers," prove to them that radio has come to stay. Improve your set. See what distance you can get out of it and communicate with everybody you hear at any great distance. Boost radio to your friends who have no sets. If you have a radiophone transmitter, cooperate with the neighbors by transmitting for their benefit. Get acquainted with them. Help them to become fans. If you have a spark station, try to help out by trans- mitting only when necessary. Cut out talking to the fellow on the next block just to hear your spark work- ing. If you can play any instrument — outside of a receiv- ing set, of course — apply to your nearest broadcasting station and offer your services. They will be glad to have you. You Old Timers ! Get acquainted with the little fel- lows. Show them what they can do with a little time and patience. You had to be taught first. You Experimenters ! Try out new ideas. Everybody is looking for them. And you may strike something big. See if the pastor of your local church wouldn't like to have you install your set for a couple of nights and give small radio recitals from the broadcasting sta- tions. Interest the merchants in your locality. Maybe they don't realize that they are letting a good thing get by them. In any event, celebrate National Radio Week and be a National Radio Week booster! Radio Rules for the Day, Week and Month MANY who own radio sets believe that once the sets are in working order and bring in signals, the only thing left to do is to watch the batteries. A radio set isn't like an egg — it im- proves with age. A radio set needs looking over once in a while. Dust is an enemy of radio, because it generally forms a short circuit. Aboard ship there are certain things that are part of the daily routine that must be done. They serve to illustrate the care that should be taken with a radio set. Here is a set of rules to follow : Daily 1. Wipe off all instruments care- fully with chamois skin or a very soft cloth. 2. Examine contacts of all re- ceiving circuits and remove dirt and corrosion. 3. If using crystal detector, clean by immersing in bisulphide of car- bon. 4. Clean spark-gap and transmit- ting apparatus. Inspect all trans- mission leads both on the back and front of board. Weekly 1. Rub all moving parts lightly with vaseline. Blow out variable condensers to remove particles of dust that may collect between plates. 2. Clean transmitting condensers and inspect the connections. 3. Gean key contacts and dress down with a light filing, if found to be pitted. 4. Rub the antennea switch blades lightly and see that the clamps are making good contact. Monthly 1. Test and charge storage bat- teries. See that the solution is clean by use of hydrometer. 2. Make note of any deviation in the operation of any of the instru- ments and file same with the head of the department. 3. Inspect antenna connections and wipe off all insulators with stiff brush dipped in carbon bisulphide. FANS, AMATEURS, DEALERS. BROADCASTERS, MANUFACTURERS, AND THE GENERAL PUBLIC Arm Loalrimg Forward to NATIONAL RADIO WEEK DECEMBER 23 TO 30, INCLUSIVE All Intereetee1 ia RaJio Skeuld Hai» to Male* Tab Eveat a SauuUag If yn vast to km mmn aheat k NATIONAL RADIO WEEK EXECUTIVE COMMITTEE J. ANDREW WHITE, Oil- 3M BROADWAY MEW TORE Be a National Radio Week Booster Digitized by Google

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12 RADIO WORLD Factors That Effect the Range of Radio Transmission By B. R. Cummins Radio Engineer, General Electric Company. ONE of the questions almost invariably asked regarding a radio transmitter is, "How far will it send?" This question is justifiable. It has become standard practice with builders of radio-trans- mitting equipment to carefully specify the conditions under which any guaranteed ranges can be made. Even then it is seldom that a con- servative company will guarantee transmission at all times. In the first place, a radio trans- mitter will transmit several times as far at night as in daylight ; it will transmit farther on a dark night than on a moonlight night. This is due to the fact that sunlight and moonlight causes an ionization of the atmosphere, which results in much greater losses than occur when such ionization is not present. The greatest ranges are obtained when the atmosphere be- tween the transmitting and receiv- ing stations is most nearly a perfect insulator. The range depends on the nature of the territory lying between the transmitting and receiving stations, the greatest ranges for a given power usually being obtained over water. Any metal, particularly iron or steel, lying between the stations will cause a loss of signal strength. Such metal may either be in the form of artificial structures such as build- ings or building frameworks, or may be in the form of ore deposits. Some sections of the country are noted for their poor location for radio re- ception, and the cause of this can usually be traced to this reason. In man/ places it is possible to re- ceive effectively from all directions but one, and it is usually found that in this direction a metallic structure, or a metal deposit, is responsible for the lack of reception. A radio station which can be de- pended upon for reliable communica- tion, through the winter months, for a given range can only work ef- fectively during the summer months over a fraction of this range, as- suming that the power of the trans- mitter is not increased. This is not due to any dimunition of signal strength, but to the percentage presence of so-called static disturb- ances during the summer months. Static disturbances, which result in cracking, hissing, or grinding noises in the receiver head-phones — fre- quently sufficient to make this radio signal unintelligible — have been the subject of investigation and analysis for many years, during which time many attempts have been made to determine their origin and means for preventing their detrimental effect on radio reception. While some very special receiving-equipment and an- tenna systems have been devised to increase the ratio of signal strength to static strength (the so-called ' signal-static ratio"), the most posi- tive way of overcoming static seems to lie in transmitting sufficient power to make the radio signals in- telligible even in the presence of static. This was the procedure fol- lowed, for example, at the Lafayette Station in Bordeaux, France, built by the United States Navy Department during the World War, for reliable communication if transatlantic ca- bles were cut by the enemy. This station has a capacity of 1,200 kilo- watts. The range depends, also, on the type of receiving equipment which is used and the ability of the op- erator to use his equipment to the best advantage. A receiver with one or more stages of amplification will receive stations which cannot be heard without such amplification. There is a limit to the extent to which amplification can be used. It does not serve, for example, to over- come static disturbances, because such disturbances are amplified to the same extent as the radio signal itself, leaving the signal-static ratio the same and, therefore, not making the message any more intelligible. The wave length at which trans- mission is carried on is also an im- portant factor in the range of a given power. Energy radiated at short wave-lengths is absorbed to a much greater extent than energy at longer wave-lengths. For thia rea- son, very long wave-lengths, com- paratively, are usually used for a long distance such as transoceanic communication. The personal equation of the re- ceiving operator is of importance. Signals which are quite readable to some operators are absolutely unin- telligible to others. The number of stations working in close proximity also decrease ranges which would otherwise be obtainable; for many signals which have sufficient strength to be easily interpreted are made unreadable by interference caused by other sta- tions. In general, therefore, in specify- ing the range of a radio transmitter, it is necessary to specify whether transmission will be carried on by day or night; in winter or summer; the type of receiver, and the amount of amplification; the nature of the country lying between the transmit- ting and receiving stations ; whether or not uninterrupted communication is required or whether so-called "de- ferred service" is satisfactory; the wave length on which transmission will be carried on ; the kind of trans- mission desired, that is, telephony, continuous wave telegraphy or in- terrupted continuous wave teleg- raphy; the vicinity in which the transmitter will be located with re- spect to other transmitters; and, lastly, but by no means of least im- portance, whether or not the range specified, even after the foregoing conditions are known, shall be a con- servative one or the maximum ex- pected. It is impossible, in a very brief discussion, to analyze more fully the various factors entering into range considerations which have been enumerated ; but the mere mention- ing of the existence of these factors should be sufficient to make all of us realize that a brief statement to the effect that a radio transmitter has a range of, say, 500 miles, is practically meaningless. This does not mean that reliable communication cannot be carried on over given distances, for a careful consideration of all conditions will permit satisfactory equipment being installed. Such equipment will fre- quently transmit distances far greater than the rated range of the set. For example, a transmitter manufactured by the General Elec- tric Company which is rated, under definite conditions, at 175 miles, has recently communicated by telephone over a distance of 4,050 miles. In view of the foregoing, anyone concerned in the range of radio sta- tions should assure himself of the conditions under which the trans- mission has been, or is to be carried on, before arriving at any definite conclusions. Digitized by Google

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RADIO WORLD 13 Remote Logging Camps on Pacific Coast Get News Daily by Radio WASHINGTON, D. C— The spirit and morale of the logger, situated far within the fastnesses of the great Pacific Coast forests, has been materially improved since the installation of modern radio- receivipg sets in logging camps. Many of the western newspaper broadcasts carry the daily news of the world into the heart of our lumbering districts where their daily papers do not reach and the telephone is not available. Instead of waiting a month to learn of some event in the outside world, the logger gets press dispatches daily. Thanks to radio, he is no longer a backwoodsman, in the old sense of the word. He received the news referring to the President's message on the Ship Subsidy Bill and the final score of the Army and Navy football game almost as soon as the city radio fan. Forest Workers Gat Forty Stations "With modern apparatus of the vacuum tube type, the logger can tune in on no less than forty broadcasting stations from Calgary to Los Angeles, and from Denver to Portland," accord- ing to the National Lumber Manufac- turer's Association, whose research department has been devoting consider- able time to the use of radio. Up in the forest-clad hills of Oregon, far from the railroad and mail routes, a digest of the daily news or a concert from San Francisco, "listens pretty good," as one logger put it. The logger's radio set has a more important use than its recreational value, however; it is a business asset in the remaining big timber stands of the country. Through the aid of the fleet of airplanes, assigned to forest- fire observation by Major General Patrick, of the Army Air Service, each of which is equipped with sending and receiving radio, conflagrations in the districts patrolled have lessened not- ably. Co-operating with federal, state, and private forest-protection, high-flying airplanes cover more territory in a day than a forest ranger on foot could cover in three months. "Spotting" a fire, or smoke, the plane hovers over the site while the observer plots the location on a map and then broadcasts a fire warning giving the location. Sta- tion operators equipped with receiving apparatus catch the air scout's message and relay it, usually by private phone lines, to the ranger or patrol station nearest the fire, and within a few minutes detachments of skilled fire- fighters are enroute to the section in danger. Since speed is so essential in By Carl £. Hawes (Photo by Nations! Lumber Mfrs. Assn.) Lascars of to-day art anjoytns; radio as ■such as dtr fans. "HJch-CHmbsrs" crawl to tha up par braachsa of trass Ml fast Mgk to ring tha aa rials, carry Ins axas to trial as wall as a Baa by which the Is fighting forest fires, first the airplane, and now radio, won the respect of the owners and operators of timber lands. Radio also serves to anticipate the approach of lightning storms and to approximate their intensity by means of a static barrage which might be called a "radio lightning recorder." This consists, the Lumber Association states, of a movable loop-antenna which rotates about a vertical shaft, not unlike a radio compass. By turn- ing the loop parallel to the general direction of the oncoming storm, the direction of approach may be de- termined with an error of less than four degrees, as the static discharge is at its maximum when the loop is parallel to the line of approach. Radio Lightning Detectors The purpose of learning the direc- tum of the storm is to enable the mem- bers of the patrol to plot its course and send out observers to locate trees struck by lightning. Lightning is said to cause twenty-five per cent of forest fires, and its particular hazard lies in the fact that unseen bolts strike trees and smolder for days before actually breaking into flames. The static barrage, the latest of radio fire-fighting equipment, has been operated quite successfully. Tech- nically it measures the frequency of the static discharge and records it on a dial or indicates it visibly across a spark gap. When the frequency of the discharge becomes excessive an automatic electric gong is rung to an- nounce impending danger. The direc- tion of the storm is then determined by means of the radio loop, and by the time lightning is flashing over the stands of timber, patrols have started through the threatened district, alert to spot trees struck by lightning. Many of the forest wireless stations are manned by ambitious young ama- teurs, some of them owning their sets, and all of them seeking to do con- structive radio work and perfect their knowledge. One privately owned re- ceiving set is reported to have picked up accurately messages from four air- plane patrol routes miles apart. Lofty Aerials, 200 Feet Hick City amateurs who boast of thirty- foot aerial masts, would be envious of the natural masts available in the west- ern forests, where giant fir trees tower three hundred feet. At least they would be envious until they began to wonder how to utilize this excessive height for stringing an aerial. On the camp's "high-climber" evolves the job of rigging the lofty antenna. He is skilled in climbing tall trees, as part of the logging business demands daily trips aloft to oil pulley blocks for cables or to prepare a new setting for the yardage operation. By skillful manipulation of a single loop of rope about his waist and around the bole of the tree, the high climber, equipped with a pair of leg-irons, or spurs, slowly raises himself upward. With a deft twist of his wrist, he flips the rope upward a foot or two at a time, trust- ing his weight to it while he replants his leg irons a little higher on the trunk. It is a task the city-aerial builder would not relish. It requires unusual skill and steady nerve on the part of the climber; but that veteran thinks nothing of it. Foresters and lumbermen say that, in the Pacific Coast timber-belt, radio has accomplished, within a few months, what would otherwise have take* de- cades to bring about. It has become a permanent fixture tending to promote both contentment and efficiency, as well as to afford a means of fire protection of hitherto undreamed of worth. Digitized by VjOO^LC

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14 RADIO WORLD Radiograms The Latest Important Radio News Briefly Told for the Growing Army of Radio Fans PRESIDENT HARDING'S message to Congress was suc- cessfully broadcast from NOF, Anacostia, D. C, on Tues- day, December 5. A full-page photograph showing a similar broadcast was published in Radio World, No. 37, dated De- cember 9, the Christmas Number. Broadcasting the President's address will always be an important radio event. Three separate telephone-wire circuits carry his voice from the Capitol to the Naval broadcasting station NOF. The transmitter which picks up the President's voice on the platform in the House is part of the public-address system recently installed to carry the voices of speakers to all parts of the Capitol. This transmitter is connected to NOF by three wire circuits. The Chesapeake and Potomac Telephone Company has provided three circuits to insure against any possible interruption. One circuit will be used for conveying the President's voice, a second will be used by the engineers as an "order wire" over which they can direct operators and keep the transmitter at an even pitch. The third circuit is provided in case anything happens to either of the others. These telephone circuits are extremely important and without the greatest skill on the part of the local telephone engineers, the President's speech could not be broadcasted directly from the Capitol. * * * A now radio -receiving sot has been installed at the Govern- ment's Hospital for the Insane, Anacostia, D. G, by the De- partment of the Interior. The set has a receiving range of about 750 miles and enables the inmates to receive concerts every evening from many different sending stations. * * * Domestic exports of radio apparatus during the month of October totaled $2*7,535 and weighed 1I4.3H pounds, according to figures compiled by the Department of Commerce. The value of these radio shipments was as follows: England, $70,391 ; Quebec and Ontario, $35,728; Argentine, $32,092; Brazil, $27,072; Japan, $11,299. * • * The first broadcast of the War Department was transmitted from NOF Monday evening, December 4, on 412 meters. It was a speech on the Muscle Shoals Nitrate Plant. * * • The Weather Bureau advises in connection with a recent hurricane which occurred in the Yucatan Channel and southern Gulf of Mexico that the warnings issued by the Weather Bu- reau were promptly received by cable and by Swan Island (US). These messages were broadcast by radio and by notices to mariners as fast as received by the Panama Canal office. They were instrumental in causing some of the boats in Mr. Grouch's Radio in Danger ! (Cartoon by the New Orleans trade to postpone their sailings for a day or two. The canal and shipping interests appreciate the prompt service given by Forecaster Mitchell and the Swan Island radio station. * * * The world's record for long-distance radio transmission was broken on November 5, when President Harding's message to the world was received in practically every country of impor- tance on the face of the earth. It was* heard even in New Zealand, 10,000 miles away. The message was transmitted from Radio Central, the station at Port Jefferson, L. I., designated for international radio communication. * * » Morris Keyser, of Philadelphia, recently heard a spoken voice without an ear trumpet for the first time in twenty-seven years. A week before he heard music for the first time on a receiving set, using headphones. He believes that radio has stimulated his hearing so that he will eventually catch sound without any artificial help. * * * ■ The first detailed report to reach New York City of thai rescue of the steamer "Monte Grappa's" crew of forty-five men in midatlantic by the White Star lines, "Pittsburgh," again puts another medal on the breast of the never sleeping radio. The "Monte Grappa," a new 10,000-ton ship belonging to the Navigazione Libera Trestina, with a cargo of 9,200 tons of grain, was bound from Montreal to Venice. She left Montreal on November 5, under the command of Captain Stefano Bartoli. On Sunday, November 12, she ran into a heavy southerly gale. Her cargo shifted and the ship took a heavy list to port. Fearing his ship would roll over, or sink, Captain Bartoli ordered an S O S sent out at 7 a. m. Tuesday. His position was given as 43 degrees, 18 minutes north; 41 degrees, 55 minutes west. This call was picked up by the "Pittsburgh," and Captain Jones, after plotting his own position, found he was 185 miles from the "Monte Grappa." Radio communica- tion was kept up during the day. Captains of deep-sea vessels are requested to report the date when ice and other obstructions reported by radio from ship to ship are sighted. Many reports of this kind come to the Hydrographic Office of the Navy Department bearing only the date of the radiogram and lacking the date when the obstruc- tion was seen. Co-operation in supplying this additional fact will be thankfully appreciated by the United States authorities. * * * Weather bulletins, forecasts, and storm warnings are now broadcast from the Naval radio stations at Key West, Florida, and Point Isabel, Texas, by continuous wave (arc) instead of by spark, on the following schedules : Key West (NAR), 10 p. m., (seventy-fifth meridian time) ; wave length, 5700 meters. Point Isabel (NAY), midnight, noon, and 7 p. m. (seventy-fifth meridian time) ; wave length, 5,000 meters. * * * An applicant for radio operator's license was barred from being examined, for a period of six months, on account of having used a false name in his examination papers. Anyone making false statements in applying for examination will be likewise treated. » » * The French wireless company, "La Compagnie Generate de Telegraphic Sans Ffl," recently founded a subsidiary radio company to operate under the name of "Radio-Orient." It has started radio communications with Syria, Lebanon, and most of the European countries. * * * The decree of May 31, 1921, prohibiting the operation of radio of foreign ships in Swedish territorial waters within 10 miles (nautical) of a costal radio station is being strictly enforced. The only exception to this rule is in cases of great urgency or where the safety of the ship is concerned. Under the same decree, foreign ships in Swedish harbors may not receive radio messages without permission of the telegraph directorate. * • * The general call signal WWAA has been assigned for all vessels operated and controlled by the Radio Corporation of America. This general call signal will be used by R. G A. ships or coast stations desiring to ascertain whether there is an R. C A ship within range, and any R. C A. vessel hearing another ship or coast station calling WWAA should answer. Digitized by Google

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RADIO WORLD 15 Radio and the Woman Crystal D. Tector Says that the Women of the Country Will Be Heard from During National Radio Week A WEEK from next Saturday — December 23 to be exact — and the first National Radio Week will have started. May it be a great and glorious success from every point of view I May every city and hamlet in the United States and Canada and Cuba — and even in Mexico, where radio is be- ginning to get a foothold — celebrate it in a thoroughly fitting manner. May it be the forerunner of an annual event that will be looked for by every true American — just as is the Fourth of July or Christmas or any other happy season. » * » I KNOW that the women of the country are going to be heard from. In fact, I can truthfuly say that my radio sisters have expressed the genuine radio spirit and have planned and built in a manner far beyond my wildest dreams. I told the editors of Radio World that we would not be lacking in interest and in willingness to work. We will do our share and do it with a thoroughness that will make our place in radio equally as important as that held by the sterner sex. ♦ * * THE holiday spirit has begun to entirely envelop this big and breezy city. New York is completely permeated with radio. In every shop there seems to be something with a radio flavor — even to radio hats and radio perfumes. And most _ everyone seems to be either putting in a radio set or wanting to do so. Most every woman I meet seems to have the radio fever. It is quite the thing for a woman to say that she is able to work her own set. In fact, going up town in a Fifth avenue bus, the other day, I heard two pretty young misses talking in radio terms in a manner that would have floored an expert. AND I know of several families who are clubbing together to purchase sets. The alleged edict of selfish landlords does not seem to bother much, for excellent results are now obtained from indoor aerials. In fact, David Saranoff, vice-president of the Radio Corporation of America, recently sent messages to England, France, Germany and Norway, and received answers on an indoor aerial. Some of the loop affairs that I have seen are very handsome and would look well in a sitting room or parlor. * » * THE women of the "upper ten" are having their sets made to match certain effects of their furnishings, for radio parties are something of a vogue in New York this winter. I have seen several indoor affairs — and have heard of others — that were broadly extravagant in finish and coloring — some even being silver mounted. Of course, such sets are only for those who can afford them, and do not enhance reception to any extent; and I simply mention them to show how the craze is spreading. * * * ONE does not need an extravagant set. The best results are obtained from sets that are well made and, above all well managed. The thing is to know your set. One gets better results from a motor car, a watch, a cooking stove, or any other commodity if one really knows it. So to every woman who contemplates owning a set I say, "Learn to know it," and you will be surprised at the results that will follow. Study it as you would study a child and you will find that it will be the greatest source of joy you can imagine. You can not install a set and start it going like a phonograph. It isn't that sort of mechanism. Take time — and know it inside out. . Radio Penetrates Fog What Is Being Dona by Lighthouse S«r- • vice to Safeguard Shipping THE greatest peril to shipping is fog. Until recently the captain of a ship has. had no practicable means of accurate- ly locating in a fog either his own ship or other ships which he is meeting. The ra- dio fog-signal and radio compass give the navigator accurate bearings in fog just as well as in clear weather. In his annual report to Secretary Hoover, the Commissioner of Lighthouses states that several additional radio fog-signals have been installed during the. past year, in- cluding one on the new lightship off Cape Hatteras, and one on San Francisco lightship. The United States now has five such stations regularly in operation, and six more will be installed in the near future. The United States is in advance of any other nation in the establishment of these protective signals. The lightships are the outermost signal stations of the country, many of them being anchored in the open sea, miles off the coast Arrangement has been made this year between the Navy and Commerce Departments, for the Light- house Service to take over the radio communication equipment on the light- ships, placed there mostly during the World War. Hereafter regular radio- service will be maintained with twenty of the outside lightships off the Atlantic, Gulf and Pacific Coasts; this will be of great value both in safeguarding and operating the lightships themselves, and in reporting the needs of other vessels, or of boats in distress. Provision is be- ing made to receive radio broadcasting on these and other isolated vessels of the Lighthouse Service, and radio tele- phones are being tested for remote lighthouses. A Quebec Guide Listens In Said It with Letters THE following letter was recently re- ceived by the General Electric Co.: "WGY, Schenectady General Store, New York State, Sir: i am gide for hunter man wot come at dis place Lac-des, isle for hunting deer, dese hunter man" bring it wit him a machine for heer you spik Sunday nite also tuesday nite i heer song about my old modder dats long tim i dont see my modder and i tink dats dame fine song also i heer oder song i dont no de nam. tuesday nite storie for de small boy and girl bout mate de star shine for dem if dey is good boy and girl, hunter man laff lik hell an tole me ax you how we mak some moon shine. i hear you spike jus de same lik your at me place i ting you' have good ma- chine i lissen more nex week, tank you and much oblige gide Camille Poirier Chemis P. O., Quebec, Canada" Listen In — Then Write RADIO WORLD has received a letter from a reader — a member of a radio club — who puts forth a little idea that, to our way of thinking, is a fine stunt. The letter is as follows: "We have a small club of listeners and very often hear fellows in other States. We think it would be a good idea if, when anybody else hears a station, he would write and tell him about it. By doing so, we can get and exchange little helpful hints and ideas. It is always a pleasure to know that one is heard in other States and cities. "We ask anyone reading this in Radio World to write us and start the ball roll- ing. "Listen in — then write I" — Charles Doherty, 746 Howard avenue, Bridgeport, Connecticut. Hook-up in Radio World Bring* Mail too Big to Handle IN Radio Womb No. 30, dated Oc- tober 21, there appeared a hook-up of a single-coil receiver designed by Mr. W. Miller, Southern Methodist Univer- sity, Dallas, Texas, with an invitation to amateurs who delight in experimenting to give it a try-out. That the invitation was heeded — and that there is a keen in- terest in hook-ups that are new and original — is attested by the following (letter from Mr. Miller: Box 222, S. M. U, Delias, Tana, Editor, Radio World: Since you pobnshsd a diagram of arjr etretrft. In your Issue No. St, I have keen snowed wader with mall. Inasmuch as } am a student, 1 cannot reply individually. I have received over MM requests for further Information, description, pans! lay-out, and many other things and I would like to knew If yen are in a position to publish the matter. Yours very truly, (Shmed) W. MILLER. Are there other radioists who have original hook-ups they would like to have published, so that the vast army of radio fans may have a chance at them? If so, it is evident that Radio World is the publication through which to present them. It would be interesting to learn how many fans did not write to Mr. Miller. To many anxious inquirers I RADIO WORLD has no free list. One eaerr b sent as a voucher to each a J » ei tinea, or advertising- agent represented In serront ■es. AU ether copies are paid for em subscription or tkrwogh the news Digitized through ed by Google

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16 RADIO WORLD Latest Photographs of the Week Sho (L-eft) The radio broad- casting* apparatus recent- ly installed in the rectory of Calvary Baptist Church, New York City. This is I over which the ■Stra- presidea. Dr. Straton haa joined the rank* of min- istera who believe in reaching as large an audi- ence as possible and real- ize that the only way to do so successfully la by study. Calvary set. Dr. Straton decided that his sermons — particularly those regarding the Ku Klux Klan — ware being heeded by many people outside bis own parish, so he had the transmitting that all who are In charge of the set. (Above) Now Yorh, is new football rules at the WGY Is talking directly at a of him. This picture gives an excellent idea of talking for broadcasting— hi a perfectly natural (C. P. & A. Photos) (Above) Dr. Albert Abraxas, noted pathologist, who is bow on the Pacific Coast, demonstrated his little "radio love detector," or, scientifically called, "electronic energy detector." This shows, right to left, Joseph O'Connor, radio expert. Dr. Wlrkllch, and Miss Ruth Rittman and »!»<"'! Dr. Albert Abrams, holding a test of the machine. The wished if ,he was in love. Dr. Abrams told her to the "detector" over her heart. The Digitized by Google

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RADIO WORLD 17 lew Radio Put to Startling New Uses (C Wide World Photo.) (Above) Thomas Donnelly and J. H. Jenkins, prominent clubmen ol Chicago, have equipped > radio station atop the roof of tho Drake They spend their spare time transmitting concerts with a radius of 1,200 miles. They assume all expense and pay prominent stars to sing or play for the benefit of radio fans. Messrs. Donnelly and Jenkins have a novel arrangement of "plugging in" on any of the hotel ballrooms, thereby being able to broadcast all other concerts given at the hotel, aside from their own. They are known to "fans" as WDAP and »XA. The photograph shows Mr. Jenkins and Ralph Shugart at work transmitting. ari| picture below) Radio is now used as an aid in securing recruits for United States Army. The photograph shows Sergeant George Kline i radio set which he rigged up on the roof of a skyscraper ■ear City Hall Park, New York City. Assigned to the duty of securing i for the Army, he decided on this novel scheme. And it may be said that he has already recruited several dozen men who, otherwise, have given their services to their country. Sergeant Kline's set, is simple and effective. He is a pioneer among daft) Han la a modem Santa Claoa and the very transmitting set > which he will speak tehta kg ion of children this It is said Six in" he United States, and ■sailj three million of 1 are children. So, this Eve, when dad I his famous recitation, ""lwne the Night Before," « he is amk *^ (C. P. ft A. Photos) (C. Underwood & Underwood) (Above) Did you hear the cheers when Princeton defeated Yak and Harvard, and Yale defeated Harvard, during the recent football season 7 Did you hear the Army and Navy boys sing during their recent thrilling game? This Is one of the devices that brought these effects to you and permitted yon to hear them as plainly as If you were right there in a front seat. The microphone, that cylindrical object so clearly shown in this photograph, la a wonderful thing. No sound is too insignificant for it to catch. It performs It. task with accuracy and precision. I« has helped to give outdoor sports a world-wide range of Interest.

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IS RADIO WORLD With the DX Night Owls Page Kenneth F. Smith EDITOR, Radio World: — I have a home-made receiving set, using a modified Colpitt's circuit with direct coupling and one Aeriotron (WD-11) vacuum tube operated on one dry- cell, with which I heard station KHJ, "The Times," Los Angeles, Cali- fornia, on two different occasions, namely: November 13 and 16. In addition to musical numbers, I heard two press mes- sages broadcast by them which I under- stood very distinctly— one regarding the severe snow storms in the vicinity of Cheyenne, Wyoming, and the other re- Sarding farm loans by Federal Reserve anks. These facts may be verified. I figure Los Angeles a little over 2,000 miles from Cincinnati. In addition to the above, I have heard PWX, Havana, Cuba, three times re- cently— a distance of over 1,450 miles, air-line; Denver, Colorado (DN-4), a dis- tance of about 1,250 miles; and numerous other stations from 500 to 1,000 miles distant, such as Fort Worth and Dallas, Texas; Kansas City and Jefferson City, Missouri; Des Moines, Davenport, and Ames, Iowa; Minneapolis, Minnesota; Schenectady, Troy, and New York City, New York; Springfield and Bedford Hills, Massachusetts; Newark, New Jersey; Anacostia, D. C; Atlanta, Georgia; and other nearby stations too numerous to mention. I would not even intimate that this record has not been, or will not be, sur- passed; but I think it is a fair record for a detector-tube set with no, stages of am- plification, using so little voltage. I would like to call the attention of Mr. Kenneth F. Smith, Birmingham, Alabama, to this letter, as he claims a record of 1,667 miles and says, "Come on, you amateurs; step up and get your feet wet I" I say, "Come on in, the water's fine!" I will be glad to furnish the hook-up I am using, upon request. — F. E. Smith. 3508 Evanston Avenue, Cincinnati, Ohio. * »' * Claims a Canadian R^ ;ord 1^ DITOR, Radio World: The only radio magazine that I can get really inter- ested in is Radio Would. While reading your last issue I discovered that many of your readers have established, or are try- ing to establish, long-distance records with bulb sets. I am not in the habit of bragging, but I think I have established the long-dis- tance record in Canada so far as crystal sets are concerned. With an ordinary crystal receiver (not a loose-coupler) and a four-strand inverted- L type aerial I have been successful in hearing WWJ, Detroit "News"; WCX, Detroit, Michigan; WWI, Dearborn, Michi- gan; WJAX, Cleveland; KDKA, Pitts- burgh; WGY, Schenectady, New York. I have heard all these stations regularly. I have also heard WOC, Davenport, Iowa. Of course, I heard all these stations in the fall, when weather conditions are ideal. Still I would like to hear from any other crystal-set owner who has made a record. — W. M. Guillot, Box 224, Windsor, Ontario, Canada. * * • In 18 Days EDITOR. Radio World: — I am sending a "DX night owl's" list. I have heard on my home-made one-tube, U-V 200 hook-uo, bv Greene, published in the Boston "Globe." October 15, the follow- The Editors of RADIO WORLD will to pleased to receive sketch** at book-up* of the various "DX Nifht Owls" sandinc in records, with a view of pub Other latter* from the DX "bugs" will be published from week to week. — The Editor. ing stations in eighteen days, some of them more than once. My aerial is 42 feet high, 110 feet long, 2 wires, 4 feet apart, running east and west, T type: KYW, WKN, W1AO, WBZ, WGY, WHAZ, KDKA, WIP, W2NA, WEAN, WJZ, WLK, WHAN, WLW, WBT, WOO, WNAC, WOC, WGM, WBU, WMAQ, WSB, WAAF, WDAP, WFAS, 2X1, WFI, WJAX, WOR, WAKP, WHAS, WEAF, lOMB, WJAR, NOF, lOMK, WHA, WWJ.— William J. Head, Receiving Station WJH, 24 First Street, Bristol, Rhode Island. "Get Your Feet Wet!" EDITOR, Radio World: In Radio World, No. 35, dated November 25, a letter was printed concerning DX work. The author of this particular letter is Kenneth F. Smith, 133 Francis Street, Bir- mingham, Alabama. Mr. Smith challenged amateurs to "step up and get their feet wet" I am here with a record which, I believe, will prevent me from getting my feet wet I beg to submit the following record for one evening: All stations were heard on a one-step, using a Reinartz circuit My aerial was 100 feet in length, 50 feet high, using a water pipe as a ground. One evening I heard the following stations, all over 500 miles away : KHJ, Los Angeles, 1,535 miles; KHQ, Seattle, 1,740 miles, DN-4 and KFAF, Denver, 800 miles; WFAA and WBAP, Dallas and Fort Worth, both 750 miles distant; WNAC, Boston, 912 miles; WGM, WSB and WD AJ, all in or near Atlanta, 650 miles. The following evening I heard KHJ, CKCK, Regina, Canada, 950 miles; WAAC, New Orleans, 830 miles; WIP, Philadelphia, 740 miles: also WBAP, WFAA, WGAG, WHB, and twenty others, all over 250 miles away. Come on, you amateurs, and "get your feet wet \" I would appreciate hearing from any other amateur not using radio-frequency who can equal the above record^, sHoward J. Hall, 521 E. McKenney Street, N:on, Illinois. * • * E 70 Ft. Long, 65 Ft. High DITOR, Radio World:— The record I have established with my set, I think, compares favorably with any I have read in your magazine.. I use only a single-circuit regenerative set without any radio- or audio-frequency amplifica- tion whatsoever and only one tube. Yet I hear such stations as Minneapolis; WWJ, Detroit "News": WOC. Daven- port; Fort Dodge; WLW, Cincinnati; Cleveland; Chicago; WEAF. New York (1322 miles, air-line); KDKA, Pitts- burgh; Louisville; KSD, St. Louis; PWX, Havana; WSB, WGM. WDAJ, Georgia; Charlotte. North Carolina; Des Moines, Iowa; WEAV, Lincoln, Nebraska; WFAT, Sioux Falls, South Dakota; Port- land, Oregon (2.127 miles, air-line) ; KHJ. Los Angeles (1.667 miles, air-line), and many other stations located within a ra- dius of 500 miles such as Sweeney Auto School; WHB, Jefferson City, Missouri; Denver, Colorado; and others. I use a double-strand aerial 70 feet long and 65 feet high. My set is home-made and is only a week old. The joints are not soldered yet Furthermore, this is the first set I have ever owned or operated. — R. Diamond, 413 Royal Street, New ' Orleans, Louisiana. * * * Detector and 2-Stage Tf DITOR, Radio World:— For some time I have taken a great interest in Radio World and thought I would send you the results I get with my home- made set — detector and two-stage audio. With this set and horn, which is a plain horn with receiver from head-set, I nave heard the distant station of Honolulu and several others on the Pacific Coast; also many other stations in the United States and Canada. The hook-up is my own regenerative type. — Carlton D> Shults, Fort Plain, New York. * * * First Set in His Town EDITOR, Radio World:— In Radio World, No. 31, dated October 28, Mr. J. A. Merklein, Brooklyn, New York, claims the receiving record, so I will send in the list of stations that I received on November 20: WEAY, Houston, Texas; WGM, At- lanta, Georgia; WDAF, Kansas City, Missouri; WMAM, Beaumont, Texas; WHB, Kansas City, Missouri; WBAP, Fort Worth, Texts; WHAS, Louisville, Kentucky; WSB, Atlanta, Georgia; WOC, Davenport, Iowa; WWJ.'Detroit, Michigan; WJAD, Waco, Texas; WOS, Jefferson City, Missouri; WHAN, Wichita, Kansas; WOI, Ames, Iowa; WCX, Detroit, Michigan; KSD, St. Louis, Missouri; WBZ, Springfield, Massachu- setts. AH the concerts came in clear and loud, although I am only using one stage of amplification. I built my own set on June 4. There are only two sets in this town, mine being the first Anyone de- siring the hook-up I use, please write me. Best 73. — Quentin Weaver, Saratoga, Texas. * * * With Only One Bulb EDITOR, Radio World:— Using only one bulb, I have heard over 60 dif- ferent phone stations since June, scat- tered between the Pacific Coast, Canada, and Cuba, practically every high-powered station in the East, and a score or more of the low-powered ones are heard very QSA at all times. Reception from the South and West seems to be excellent. The most distant point in the West heard was KGW, Portland, Oregon, on July 8.— Albert Bannister, 2 Wash- ington Street, Hudson Falls, New York. * » * On a Home-Made Set EDITOR, Radio Worlds— I thought you would be interested to know that on Sunday evening, November 12, I re- ceived very clearly part of the program of WOC, Davenport, Iowa, on my home- made set which is only a single detector- bulb regenerative set. I used a Meteor Antenna Plug instead of outside antenna. If you care to check up this statement, at 10 p. m. eastern standard time, WOC was sending "The Star-Spangled Banner" played by the P. S. C, orchestra.— Will- iam C. Hicks, Waterford, New York. Digitized by Google

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RADIO WORLD 19 What I Accomplish with My Home-made Set By Paul G. Watson 3 BV, West Chester, Pennsyli/ania Very neat, attractive and STATION 3 BV has made notable long-distance receiving records. On June 1, the C-W station 6 XAD, Avalon, California, was copied and con- firmed by letter. C-W station 5 XA also comes in very QSA. The station sign- ing 3 BV on C-W is Canadian 3 BV and may be distinguished from the United States stations as he uses "FM" instead of "DE" in calling and signing off. All the apparatus is home-made from original designs. For the information of those interested in construction, the cir- cuit of the short-wave tuner accompanies this article. It consists of a 43-plate .001 microfarad condenser, short-wave coupler, and two variometers. The pri- nt the layout at Mr. Watm<i wt cessfully. Phones, Magnavox, and small horn are connected to this amplifier — the small horn for sound reading of tele- graph signals, the Magnavox for music, and the headset for DX signals. Music from many distant music stations have been received, WOC. WHB, WSB, WBAP and many nearby stations. The transmitter is a low-power, coil affair, and does not use the rotary gap. Power has not been available for some time, hence the spark coil. However, tuned sharply to 190 meters, I have worked 44 miles. It is inductively coupled and radiates about three-tenths of an ampere. The antenna is a 6-wire, inverted-L, 90 feet long with an average height of 45 feet. The ground system is a grid of wires buried under the antenna. In the construction and design of this apparatus, many points of electrical de- sign were considered. The wire used on all the pieces of the set is No. 14, and connections on the table were made with No. lO wire. Care in insulating connect- ing wires, p-oper arrangement of ap- paratus, all contr .ted to the efficiency of this static • • • The above article and Illustrations were con- SSS^U' tfr- w«**0" «» response to RADIO WORLD'S call to amateurs and fans to send ua just such material that brother radloists may nraflt ft... —L. — a _ a.1 < l m • • . Circuit of SBV for Short Waves. mary inductance-switch of the vario- coupler is back mounted and is con- trolled with a panel knob. Fine regen- eration is obtained in this type tuner. The long-wave tuner is a honeycomb- coil tuner using a feed-back, or tickler, circuit. Either of these. tuners may be connected to the audion-control panel through an anticapacity switch. This audion panel contains all the necessary controls, variable grid-condenser, vernier rheostat and B-battery switch for the "soft" tube. A two-step audio-frequency amplifier is connected to this detector. Acme A-2 transformers are used suc- ' — - «. imi nruinr rauioiszs may profit by what others are dotaf . This to an ideal little story— brief, practical, and Informative— and the accompanying- photograph and hook-up complete it and give a capital Idea of the author's " §) a v v a» veiyi sane; iMungft very attractive set.— The Editors. Battery Hints ITEEP your eye on your storage batteries. Don't let them stand too long without recharging. If you charge them at home, take them to the service station at least once every year. A few dollars spent in having an expert look them over may save the price of a new battery. Keep the tops of the elements covered at all times. The water evaporates, but the acid does not. Use only distilled water. ■jvina seiqmiplde withoufit ■ \ **** '

Art A **GREATEl\Radio Christmas THIS year the message of Christmas will flash one inspiration over all lands and to all peoples — no frontier can turn back the swift messenger, Radio, whose steed keeps pace with light. The gift of all gifts is Mag- navox Radio, the Reproducer Supreme: the gift that will mean most to every member of the family, old and young. Let Magnavox bring you daily the world's news and entertainment — the greatest victory of science, the greatest opportunity of artl R-2 Magnavox Radio with 18-inch horn: this instru- ment is intended for those who wish the utmost in amplifying power; for large audiences, dance halls, etc $85.00 R-3 Magnavox Radio with 14- inch horn : the ideal instru- ment for use in homes, of- fices, amateur stations, etc $45.00 Model C Magnavox Power Amplifier insures getting the largest possible power input for your Magnavox Radio. 2 Stage AC-2-C . $80.00 3 Stage AC-3-C . 110.00 When you purchisc a Mag- navox product you possess an instrument of the highest quality and service. Magnavox products can be had of good dealers everywhere. Write us for copy of new illustrated booklet. THE MAGNAVOX CO. Oakland, California N. Y. Office : 370 Seventh Ave. M IRadio D/ie Reproducer Supreme Digitized by Google

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20 RADIO WORLD Latest Radio Patents To Determine the Direction of Remote Radio Waves No. l,43S,f41. Patented) Novanbtr 21, UzL Pat- attMi James Robinson, Andov.r, England MR. ROBINSON'S invention relates to improvements in electromagnetic arrangements for the reception of wire- less waves, in which the direction of ar- rival of such waves from some remote point may be determined. It is known that when an electrical circuit having characteristics suitable for the reception of electromagnetic waves is arranged in the form of a closed coil, or loop, the intensity of the signals re- ceived upon it from a remote transmitting station will be at a maximum when the plane of the coil coincides with the direc- tion of propagation, or arrival, of the waves; and at a minimum when the coil is at right angles to the incoming waves. By rotating such a coil about an axis, it will be possible to discover the bearing of the transmitting station. Mr. Robinson uses a pair of aerial coils in vertical planes set at an angle to each other — preferably at a right angle — and rotated about a vertical axis until no ap- preciable difference in strength of signal is found, when the effect of that coil which lies at right angles to the direction of arrival of the waves (the bearing of which is desired) is superimposed posi- tively or negatively upon the effect of the other coil. Obviously the bearing can Holder for Hard Usagre No. MSZJK. Patented, October 24. 1M2. Parnate** Jobs O. Gargaa, Brooklyn, N. Y. THIS invention relates to socket struc- tures, and has for its object the pro- vision of a socket in which spare vacuum- tubes used in telegraph sets may be carried without undue vibration or liability to break- age- In telegraph sending and receiving sets, particularly of the portable type for field work, it is often advisable to carry spare tubes. Due to the rough usage to which these sets are often subject it is necessary to provide a holder for them, of such con- struction that the tube shall not fall out Mr. Gargan's invention comprises a socket into which the tube is inserted and to which it is locked by a bayonet slot-construction acting in combination with a resilient means at the base of the socket which operates on the base of the tube to hold it in place. Eighth Figure of Mr. Robinson's patent showing oUagramatlcally a method of fitting coiU to aircraft. then be determined by the position of the first coil. In the case of coils actually at right angles, the position for the reception of maximum signals 'oy one coil can be roughly determined. By the superimposi- tion of the other coil, this maximum posi- tion can be definitely fixed. Not only does this arrangement repre- sent a considerable saving of time in the determination of a bearing but it is now possible to appreciate and interpret sig- nals, simultaneously and without inter- ruption while their direction it being de- termined. Broadcasting Gain for November Is 17 Stations DURING November, the Department of Commerce licensed 46 broadcasting stations and cancelled 29. Three of those deleted were transferred to other owner- ship and have been recorded as new sta- tions. The gain for the month was 1/ stations, which indicates that the looked- for saturation point in broadcasting sta- tions has not yet been reached. The stations whose licenses were can- celled in November follow: WLAT— Chas. G. Bosch Co., Burling- ton, Iowa. WBAE— Bradley Polytechnic Institute, Peoria, Illinois. WEAP— Brown's Business College, Pe- oria, Illinois. WIAN— Chronicle & News Publishing Co., Allcniown, Pennsylvania. KFA V— Cooke & Chapman, Venice, California. KDZJ— Excelsior Radio Co., Eugene, Oregon. WKAJ— Fargo Plumbing & Heating Co., Fargo, North Dakota. WK AT— Frankfort Morning Times, Frankfort, Indiana. WDAW— Georgia Railway 4 Power Co., Atlanta, Georgia. WGAF— Goller Radio Service, Tulsa, Oklahoma. KDYN— Great Western Radio Corpo- ration, Redwood City, California. WRAQ— Myron L Harmon, South Brr "•>na. Publishing Co., Kla- Kon. on Chronicle Publish- ii, Texas. WSV— Dr. L. M. Hunter and G. L. Car- rington, Little Rock, Arkansas. W HAL— Jeffrey & Derby, Lansing, Mich, (now "Lansing Capitol News"). WFAX— Arthur L. Kent, Binghamton, New York. KHJ— G. R. Kierulff & Co., Los An- geles, California. WMAU— Louisiana State Fair Asso- ciation, Shreveport, Louisiana. WIAG— Matthews Electric Supply Co., Birmingham, Alabama. KFDB— John D. McKee, San Francisco. KDZD — W. R. Mitchell, Los Angeles. Wouldn't It Be Great, If— Tk« fellow with the phone eat on too next bleak, who radiate* 'steea amps, wouldn't turn on full power when he talk* to the fellow two block* away? • • • Every time you have a bunch of people for company your set would work a* well a* It doe* Ju*t after they go home 7 • • • You ceuld get the results out of your set that you tell the ether hams you do? • • • You could open up a radio star*. Think of all the apparatus yen could fool around with, and It wouldn't coat you a cent? Whan you asked a radio salesman •am tion he would answer m such a way that It wouldn't make you aihamsd to say yen don't understand? The upper sketch Is an elevation of the tube and socket, with a por- tion of the base brok- en away, showing- the device attached to a portable telegraph est J At right 1* a plan vie* Sr looking downward on the device with tube 7 socket. d> KFA B— Pacific Radiofone Co, Inc, Portland, Oregon. WTK— Paris Radio Electric Co., Paris, Texas. KYG— Radio Service Bureau, Inc, Portland, Oregon. WHAN— Southwestern Radio Co., Wichita, Kansas. WDAA— Ward-Belmont School, Nash- ville, Tennessee. WHAT— Yale Democrat & Yale Tele- phone Co., Yale, Oklahoma. WEAZ— Redmond, Donald, Waterloo, Iowa. 12 New Broadcasters The following limited commercial or broadcasting stations, on 360 meters, li- censed week ending November 29: KFGG— Astoria Budget, Astoria, Ore- gon, 5 watrs. WPAG— Central Radio Co., Inc., Inde- pendence, Missouri, 500 watts. KFEJ— Guy Greason, Tacoma, Wash- ington, 10 watts. WSAJ— Grove City College, Grove City, Pennsylvania, 100 watts. WCAP— Kalamazoo College, Kalama- zoo, Michigan, 100 watts. KFCL— Los Angeles Union Stock Yards, Los Angeles, 500 watts. WOAR— Henry P. Lundskow, Ke- nasha, Wisconsin, 100 watts. KFCQ— Motor Service Station, Casper, Wvoming, 50 watts. WOAZ— Penick Hughes Co., Stanford, Texas, 100 watts. WOAQ — Portsmouth Radio Associa- tion, Portsmouth, Virginia, 150 watts. WCAW— Woodmen of the World, Omaha, Nebraska, 50 watts. KFDF— Wyoming Radio Corporation, Casper, Wyoming. One new Class-B station, 400 meters, was licensed : KFDB — Mercantile Trust Company of California, San Francisco, 500 watts. Digitized by Google

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RADIO WORLD 21 The NWHeet BWt Wan Tumr a. the HwM Ontr MuM * PP « I Ik M tar peaspblet. L. W. GOODMAN DREXEL HILL. PA. Mr . MUlfse. N. «.. I iM «M •••OMAN. WmM h» maty •* too** nestht age. GITHENS TRUTONE RADIO HORN— LOUD SPEAKER Firit on* to sell on ten day trial Money back Guarantee Ratall Prica $21.00 Includes Load Speaker muM iu • Un-ilsf IrUJ nmwubMk rmnslse If set wrrlxl b7 raur Jm1.i «ni« us. £Hrrrtt>ulor« and Dealers, wrrtle t AUTO PARTS MFG. CO. U1S Trombijr At*., Detroit, Basis of Radio Measure- ments Barwa of Standards Develop* Precia* Method of Standard! ring- Wave- Lengths and Frequenciaa THE Bureau of Standards has devel- oped a very precise method of stand- ardization of radio wave-lengths and fre- quencies, which is the fundamental basis of radio measurements in this country. By the process used, the frequency of radio waves is compared with that of an audible musical note. A tuning fork is mounted in such a way that it may be made to control the frequency of an os- cillatory circuit. The frequency of an- other oscillatory circuit operating at much higher frequencies is then com- pared with it by an oscillograph. This latter instrument consists of the cathode-ray tube — a special kind of vacuum tube in which the narrow stream of electrons is subjected to the action of electric fields applied by the two alter- nating-current generators. When neither generator is operating, the electron, im- pinging on the active screen at the end of the tube, cause a single luminous spot. If one generator is connected, the spot is deflected back and forth along the single line, horizontal or vertical, as the case may be, with such rapidity that it ap- pears as a solid line. If both generators are applied simultaneously, the spot os- cillates both horizontally and vertically, and appears, in general, as a blurred lu- minous rectangle. If, however, the fre- quencies of the two generators bear a simple ratio, such as four to one, the spot traverses and retraverses a definite simple path, forming a figure by which the frequency ratio may be recognized. It has been found possible to compare frequency ratios as high as 21 to 1. The bureau is at present engaged in the standardization of a high-precision standard wave meter by this means. A tuning fork of known frequency, approx- imately 1,000 cycles per second, is used as the basis of the standardization. A low-frequency generator is tuned to suc- cessive multiples of this frequency by means of the cat!:ode-ray oscillograph, and corresponding settings of the wave meter are obtained. A third generator is similarly tuned to multiples of these frequencies, and thus by successive stages the standardization is extended to include frequencies as high as 5.000 kilo- cycles (60 meters). It is intended that this wave meter be used as the basic standard for the standardization of com- mercial wave meters. Lighthouse Men Organize SEVERAL men in the Lighthouse Bu- reau, Washington, D. C., have been dabbling with radiotelephone receiving sets, and it has occurred to them that their experience would be valuable to keepers and other members of the service who would like to enjoy the pleasures of the radio concerts. There- fore, they propose to organize a radio club among the amateur fans of the service. The initiation fee will be a pos- tal, or letter, stating approval of the scheme and a desire to be enrolled as a member. The dues will be a word or two from time to time telling of diffi- culties encountered, results secured, or asking information. A space in the Lighthouse Service Bulletin will be re- served for answers to questions and in- teresting information that will enable them to construct their own sets or im- prove those they already own; also to conduct a clearing house for new ideas. Articles will appear from time to time on different phases of the subject. Charles C Brush is in charge of the plan. Pignolet RADIO VOLT-METER ONE INSTRUMENT MAKES ALL TESTS Write for booklet with aa for tee tin* and adja.tiaa Radio Seta. Thooaande now In nee gfro a boo lata aatiaf action. Pignolet Instrument Co., he. 114 Liberty Street, Now York. N. Y. RADIO FINDS A BETTER CONDENSER lie plalea epecod cleat alee It the ea- sel tualaa aealltlee. It la a dle-caai product: the etatleeary plal«e arc can col 14. accurately sac permanently spaced, on three aprtcbt Mi p porta, while the movable platee are eeat an the cooler revolvta* spindle. Pimee canael loeeea. which ellmlaatee afcorfra*. Each reaoeaaer haa ear Price, tt Ptatee t*.ss anek «S Plalee ** IS earn TO JORRKR* A*l» ItKAl BUS A arLKMtin PR»P«k»ITtOII Bayley Condenser Co. la*- IOC Teed m.. Broealy*. N. T DELICATE SOLDERING U»th the manufacturer*/ and amateurs' problem on all line work la readily solved by the instrument constructed for this particular purpose. THE POST SOLDERING IRON Platinum Heating Unit — Interchangeable Tip — Universal Current One Half An sal Mae $6.00 From Tow Dealer or Write Awarded Certificate of Excellency, N. T. Evening Mall Radio Institute POST ELECTRIC COMPANY, (Dh. 5») M E. 42nd St, New Test YOUR NEWSDEALER will deliver RADIO WORLD te your hose., la ardor to he sure of getting RADIO WORLD reeolarly, and ol not missing a single Issue, w. suggest that you *«th»r SMeocnbc direct er through yew* erws- deeler at SS at ■ year <SJ Issues). ON IB month., end tlM ihrse months. Or instruct your ai ■ .QoarQr to deliver RADIO WORLD regularly to your heme each week. Drshire will take standing si dare aad snake deliveries e4 paper wheewver request**. Radio World. MPS Broadway, New Vera.

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Bank Operates Giant Radio San Francisco Institution Broadcasts News to Fans West of Rocky Mountains THE most powerful radio broadcasting- station on the Pacific Coast — and one of the most powerful in the United States — is now "on the air" in regular service on Telegraph Hill, San Francisco. The station, officially known as KFDB, was established by the Mercantile Trust Company of California, and is the first on the Pacific Coast to be built, owned, and operated by a bank. KFDB has a sufficient range to reach all points west of the Rocky Mountains. It is broadcasting every day (Sunday excepted) commercial, financial, and agricultural in- formation between the hours of 10 and 11 a. m., and 2 to 3 p. m., with a musical pro- gram between 9 and 10 p. m. The first attempt at broadcasting from KFDB, in August, developed an interesting New Firms and Corpora- tions (The firms mtd cerfmrmtiens mentioned m these eohmmu cmn be reached by commum eating with the ottenuyt. whose addresses are given whenever fOteibie.) Benjamin Electrical Supply Co., Manhattan, $10,000; B. Schmones. J. Solomon, D. Getz. (At- torney, M. S. Yocheleon, 320 Broadway, New York.) problem in radio engineering. The power was supplied direct from a 2.000-volt gener- ator, but the commutator hum of the gen- erator prevented satisfactory radio reception. To eliminate this disturbing noise, it was decided to install a 2.000-volt 20 ampere- hour storage battery, and use the generator for recharging the batter- in series. The Philadelphia Storage Battery Company sup- plied 333 Philco Radio A Batteries for the purpose, and regular broadcasting was started on November 1. National Radio Week Special Number ! Remember "This Is a Radio Christmas" and that millions of dollars will be spent during the holiday time for radio gifts. Be sure to get your share of this business by advertising in the issue of RADIO WORLD of December 23, which will be RADIO WORLD'S NATIONAL RADIO WEEK NUMBER Thru this medium you can reach thousands of readers, who are not only interested in radio themselves, and want new equipment, but who also will give presents to others whom they wish to make radio fans. ADVERTISING RATES: Reenter advertising rates la farce far RADIO WORLD'S NATIONAL RADIO WEEK NUMBER, as follows: (IS* a page, $5 an lack. Dteceant, lt% foar Usaes, 18% thirteen times. Take advantage not only of RADIO WORLD'S circulation, but also its cash -thru -the- mail pulling power. Be represented in RADIO WORLD'S National Radio Week Number, and reach the many thousands who actually want your goods and are ready and willing to pay for them. EARLY COPY GETS BEST POSITIONS. RADIO WORLD, 1493 Broadway, New York Coming Events The editor! of RADIO WORLD wffl gladly publish news item* of all contemplated radis shews and exposition*. Keep us posted by mailing full talorr " SECOND NATIONAL RADIO EXPOSITION, direction Internationa) Trade Exposition Co., Chicago, January 13 to 20. inclusive, 1923, George A. King director ol publicity, 417 Sooth Dearborn Street, Chicago, DL PERMANENT RADIO PAIR FOR BUYERS, Hotel Imperial, New York City. Open froaa September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION. Grand Cen- tral Palace. New York City, December 21 to 31. Colwell * Korbell. Fiak Building, New York City, director* of publicity. SECOND DISTRICT RADIO CONVENTION, Hotel Penneylvania. New York City. March J, 2, and 3, 1923. .FIRST UNIVERSAL EXPOSITION OF IN- VENTIONS AND PATENTS, Grand Central Pal- aee^ New York City, February 17 to 22, inclusive, A Freshman Improvement "pHE very latest improvement in radio is a com- bination variable grid-leak and Micon-con- den*er. The grid-teak consist* of a piece ol fiber spe- cially treated on which a bronze spring la rotated to vary the resistance in an unbroken range, from practically aero to five megohms. The condenser i* a teited Micon-conden*er of .00025 mfd. The whole i* combined and sealed in a neat molded body with nickeled binding-pott* and a pointer and dial to set the grid-leak resistance. Every tube require* a different grid-leak resist- ance to operate at it* maximum efficiency, espe- cially when working; on weak signals. It has been found in practice that it is possible to tune in distant station* by varying the grid-leak resist- ance to the proper point. The variable grid-leak and condenser msy be used in the parts of the circuit to eliminate noise and distortion. It has distinct advantage when placed across phones instead of usual phone con- densers. This device is manufactured, by the Chaa. Freshman Company, Inc., of New York City. The accuracy and construction will be in line with the tested Micon-condenser now well known in the radio field. Improved Anti-Capacity Radio Jacks Manufactured by the Radio Improvement Co., 25 Wett 43rd Street, New York City •pHE improved Anti- -1 Capacity Radio Jack is one of the latest develop- ment* in radio and wa* designed especially for radio work. Radio en- thusiasts are quick to realize the importance of these jack*— no soldering of wire*, an important element: occupies lea* room, which is very true; inductance is practically eliminated and it has a classy appearance. This device is practically an improved radio jack, radically different from all styles of the old ordinary telephone jack. They will fit any plug. Owing to the elimination of Ions; leads, induction is minimized. They are made in single circuit, open; single circuit, closed: dou- ble circuit, closed; and both single and double filament circuit. The "A" Battery Switch is, also, s practical device which, due to its red knob, permits the "A" Battery to be disconnected or connected at a pull, or push, of a knob. Fifty-two issues for $6.00. Sab. De- partment, Radio World, 1493 Broadway, N. Y. C Digitized by Google

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RADIO WORLD 23 Radio- Wire Tables By Frederick J. Rumford, EM.., R£. No 4— Single Silk-Covered Wire Showing the Number of Feet in a Pound and Fractions of a Pound APPENDED is the fourth of a series of five tables Which the radio amateur will find useful for many purposes. The fifth table— "Double Silk-Covered Wire"— will b« published in an early number of Radio World. Size H lh. H IK M lb. K lb. 1 lb. 26 3* 78 156 234 319 21 48 96 192 288 398 22 83 126 252 378 504 23 88 168 328 488 645 24 88 198 396 594 795 2S 12S 250 500 750 1004 2* 155 310 620 930 1240 27 201 402 804 1208 1615 28 252 504 1008 1512 2023 2t 328 656 > 1312 1968 2625 36 418 832 1684 2496 3335 31 477 954 1988 2862 3820 32 609 1228 2436 3854 4876 33 770 1540 3080 4628 6243 34 969 1938 3876 5814 7757 35 1207 2414 4828 7242 9880 3S 1488 2976 5952 8828 11987 37 1884 3368 6735 10104 13474 38 2064 4128 8256 12384 16516 3* 2782 5564 11128 16592 22261 48 3368 6736 13472 20208 26847 The following tables have already been published: No. 1— Enameled Magnet Wire, Radio World, No. 34, dated November 18. No. 2 — Single Cotton-Covered Wire, Radio World, No. 35, dated November 25. No. 3— Double Cotton-Covered Wire, Radio World, No. 36, dated December 2. To Harmonize Radio Activities National Radio Chamber £f Commerce Claims There Are Too Many Broadcasters and a Concrete Study Must Be Made PLANS for the organization of cham- bers of commerce in the. principal cities of the_ country as a step towarda harmonizing, on a nation-wide scale, all radio instrumentalities — the ef- forts of which, because of the rapid de- velopment of the industry, are producing confusion and disorganization — are an- nounced here by the National Radio Chamber of Commerce, 165 Broadway, New York City. The first of these chambers, which will operate under charters from the National Chamber, will be established in Chicago. A meeting to discuss organization plans was held on Friday, December 8, at the Union League Club in that city. A na- tional gathering of broadcasters will be summoned in Chicago to take up a na- tional policy of broadcasting. The National Radio Chamber of Com- merce, it is said, has undertaken the leadership in this direction after confer- ences with the Navy Department, the De- partment of Commerce, the United States Bureau of Standards and other public and private agencies. Kenneth P. Gregg, of New York, one of the managers of the National Chamber, now in process of or- ganization, will represent this body at the Chicago meeting. Establishment of a Chicago Radio Chamber, he said, was a link in a general plan to federalize the National Chamber by the formation of similar chambers in the cities comprising the nine regional districts into which the chamber has divided its activities. With New York as the headquarters of the parent body, Chicago has been selected as the starting point from which other chambers will be brought into be- ing. Radio representatives from all over the country will attend the. meeting. Once the Chicago chamber is or- ganized, it is planned to set up similar chambers in other cities of the ninth radio district, which, besides Chicago, includes Milwaukee, Indianapolis, St Louis, Kan- sas City, Omaha, Denver, Minneapolis, St. Paul, Duluth, Louisville, and Daven- port, Iowa. The States comprised in this area are Wisconsin, Indiana, Kentucky, Illinois, Missouri, Nebraska, Minnesota, Iowa, North and South Dakota, and Kan- sas. This general plan, the organizers of the National Chamber believe, will accom- plish an essential union of national and local effort. In this way, Mr. Gregg said, local interests will be conserved and property represented in the national body, under whose charter the regional cham- bers will come into existence. In a statement issued by the National Chamber it was said that entirely too many radio stations are operating in this country. A great many of these are very small-powered stations. A concrete study must be made, it was said, to determine where these stations should be located, and what class of service they should broadcast without' interference. A study just completed by the National Chamber shows that the total area cov- ered by broadcasting stations in the United States is 179,500,000 square miles. American Radio Exposi- tion Offers Prizes to Boys and Girls IN order to stimulate interest in the wonders of radio among school boys and girls, prizes aggregating $200 in gold and a few additional prizes other than cash are being offered by the manage- ment of the American Radio Exposition at the Grand Central Palace, December 21 to 30. To the boy or girl in school or high school who enters in the contest the most ingenious home-assembled set of radio apparatus, a prize of $100 in gold will be awarded. The second prize will be $50 in gold; third prize, $25; fourth prize, $15; fifth prize, $10. There will be also several other prizes worth competing for, including ten tickets of admission to the exposition for sixth prize; eight tickets for seventh prize, and six tickets for eighth prize. To be eligible, contestants must be bona fide amateurs and bring their entry to the exposition to be exhibited. The parts may be home made or assembled and the ingenuity and original ideas em- bodied in such assembly will count as the chief factor. An inexpensive layout will have just as much chance of winning first prize as an expensive one. Pupils of public schools, high schools and private schools within a radius of one hundred miles will be eligible. Spe- cial prizes for amateurs under twenty- one years of age, who are no longer in school, will be offered. Prospective contestants must make their entry by letter (not in person) to the American Radio Exposition, 120 Broadway, New York, on or before Sat- urday, December 16, and they will re- ceive particulars relative to exhibiting the apparatus. The management reserves the right to exhibit or not to exhibit any entries. A ; jury of competent, impartial engineers in no way connected with the management of the Exposition will make the awards. "The Fool" Broadcast First Theatrical Performance to Be Sent by Radio from Stag* W1EN the Westinghouse Electric Company broadcast the perform- ance of "The Fool" from the Times Square Theater, New York City, Decem- ber 14, it was the first time in the history of radio that a theatrical performance was sent from the stage of a playhouse with the audience present and participat- ing in the event. The Westinghouse folk sent a force of engineers to the Times Square Theater Monday to install ap- paratus. The broadcasting began at 8:45 with introductory remarks by Channing Pollock, author of "The Fool." Two or three important scenes were played, the intermission being, filled by appropriate music sent from Newark. All this in- volved the use of three microphones — one in the basement of the theater for Mr. Pollock's speech, one in the foot- lights for the performance on the stage and one in Newark. The sending was absolutely synchronized, although from places miles apart. The story of The Fool" begins in a fashionable New York Church on Christmas eve, and revolves around the determination of one man to apply the principles taught by Christ Jesus to his everyday living. The ap- plause of the audience was heard all over the country. National Radio Week N«s.W Oat Next Week Digitized by VjOOglC

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24 RADIO WORLD BCM BROADCAST RADIO RECEIVER H117 people lira la leeatloas what* mm atrial la laipoaelble. Otbara abject ta thrlr prcaabieo txloc dlaAmred bj palaa aad wlree. ami m*nj daubt their abUltr «a operate acta with aorta eempllratleoa. BUaalaate thaw f Ml area by ualac BOH Badie rrcqnoacy Braadc— t reeefaera aad laalda aerial. Dealers should write BCM RADIO COMPANY YP8ILANT1, MICH. Those Football Returns by Radio Bains m Stenographic Raport of . _ mm Thay Cam* from tha Yala- Harvard Gam* CROSS kicked off for Yale to har- vard's thirty — no— twenty-yard line — ( Ray-y-y-y-y-y-y ! — H ah-vud-d-d 1 — Hah- yud-d-d I— Ray-y-y-y !) Gehrke ran it back— huh?— wait a minute — that's right —Gehrke ran it back fifteen— no— about ten yardi before he was downed. It is now Yay-hul's ball — no— Har- vard's ball— on Yale's — wait a minute — no — on Harvard's own 35 — 37—40 — am I right, Eddie?— yard line— Rekety kex-ko- MMa TIM tart, ft FNa Van RADIO FOI I1PMENT MFG. Ce"a f*\/\ Six eOeteat Baak-apa eeat apea •* 1>e- $9eUU ato-pTaT/ha. wlta aaaa "AH WaeV Oe»H- GUABAMTKKD WITH AH ABOOLPTB HOBBT-BAOH OOABAM^pB novunM of iinsniD obh Capitol Phonolier Corporation $1.50 HUNDRED FEET That will at once appeal to you. It is different and bet- ter than any makeshifts to date, being hard drawn from the finest copper having a corrugated surface with 10 collecting points on its cir- cumference. This gives a greater collective and gath- ering surface. Tbe result is extreme sensitiveness, and an increase in the range and clearness of any set from the simplest crystal type to the finest V. T. Receiver. Packed in neat cartons of 100 feet, 200 feet and 600 feet. Dept. C. Pottage paid. r*3 ex-ko-ex; Reckety kex ko-ex-ko-ex-Yalel Yale I Yal-l-le I Harmon— no — Ham- mond— punted to whozatplayer — Joe — huh? — punted to Deaver — no — to Neid- linger on the (Band: Oompah-Oompah- to-rara-tah-tah-tum-crash - boom - tab) — Yale returned to kick — no thanks, Oscar, I don't care for Scotch — (Tremendous outburst of cheering: Yah-h-h-h-h-h — Yea-a-a-a-a-a — Hah-vud-d-d-d-dl— Hah- VUD-D-D— Yay-y-y-y I) and on a fumble by— huh?— whatzat, Eddie?— by one of his own men Hammond ran the length of the field — huh? — wait a minute — Owen ran the length of the field. (Deafening cheer: HAH-VUD-D-D-D-D-DI HAH- VUD-D-D-D-D!) kicked the goal — the score is Hahvudd seven— Yahul nothing —hey, Dick, give us a shot o' that, will yer? , There is time out for— hey I— where s that flask, Sid?— for injuries to a Yale- no— to a Harvard— no— to a Yale player— Cruikshank— no— O'Hearn. (Band:Um- pah l-Umpah I-Ta-ta-ra-ta-ra-dum-la-ra) — is injured! Mallory— I mean Neidlinger —ran the ball back 10 yards by beautiful interference — got a match, Eddie? — by O'Hearn. Jordan punted to Hammond on Yale s —I mean Harvard's — 40-yard line — (Rah- h-h-h I— Rah-h-h-h 1 Rah-h-h-h !— Yahul 1— Yahul I— Yahul I). Somebody is hurt and there is time out — Hey, Damon, gimme a cigarette?— On the next play (Yay! — Whoohah-h-h ! Wow-w-w-yah-h-h-h-«ow- w-w-rey!) Gordon — no — Dunker — no, think it's Eastman — went through centre — no — left end for 10 — no— for 8 — no — for four yards. (Band : Tum-tah-ra-ra-ra- tum-tah-crash-boom-m-m 1). Somebody's hurt— where's that bottle? It is very cold here and a biting wind is sweeping across the bowl and — thanks! —here's the cork, Scotty— (Hah-vudl— Hah-vud!— Hah-vudl— Rah-Rahl — Rah! — Hah-vud-d-d!)— on an attempted for- ward—no—on a fake kick— wait a minute —on a delayed pass Jenkins — no — Owen was thrown for a loss of ten yards — where's that flask, Boxeman?— the ban is now Yale's on Harvard's 15-yard line — no— that's wrong— just a minute (Rah- h-h 1— Hah-vud 1— Hah-vud I — Har-vud I— Reckety-kex-koex-koex — Yale I— Yale 1 — Yale I— Yale!) Harvard fumbled and the ball was recovered by— thanks, Eddie! — gurgle-gurgle-gurgle — by Love joy or Cross— wait a minute— the ball was (hie) recovered by A'Hearn — O'Hearn — A' II earn (Band: Blam-blam-dah-dah- crash-bang).— H. L Phillips in "The Globe," New York. To the Mai with «■ Idea I ofar a eaaaprabaaalTa, aaaart- encod, efWeat aarrlea tor Ha prompt, laaal protection, aad tbe dave&pMt of Ua aropaalnaa Sand sketch or model aad oaaeria- tioa. for adviea aa to coat, eeereh throat* prior Uaitad tutaa oatente. etc PreHaunary adrico t»adlr famished without charge. „_0*2a3^**^V*rtta> taTafe ""SaaofieTea, RICHARD B.OWEN.P (t Ooeo BertAea. WaeMeel 117S-P Wortoarta Bats. Na B. & Subscribe for RADIO WORLD? year, $3.00 six months, $1.50 throe Digitized by Google

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RADIO WORLD 25 RADIO SALESMEN! A Rare Selling Opportunity For Lira Wir* Mm Handle Grewel Detectors ia territories not opened. Writ* f*r full pmrHculart RANDEL COMPANY • Caatt-J Ave. N-warfc, N. J. Do Too Like dear ■ad OkrtlactT If m try MARSH'S Variable AT LAST P. P. Marsh, 146 NicoU St Maw HAVKJ*. CO K*. TOBACCO HABIT BANISHED QUICK, SURE, LASTING RESULTS Tobacco Redeemer ham. he. the habit com- pletely, almost before you know it. An absolutely •denude, thoroughly reliable treatment. No matur how long the habit, or in what form used, yon will have no craving for tobacco after yon take thi* pleasant, inexpensive treatment. Thia we positively guarantee. Your money returned without argument or question If not satisfied. Write for free explanatory booklet and proof of what Tobacco Redeemer has done for men addicted Client 171 , a. Lena, Ha, PRICES SMASHED ■NSaVtal aaoaifaaATiTB vacuum tubs mxt aaeaaxuaatS rsais — l.ltl satsw. " Oar rrlss Oassaj Put r -i~- " mm. n.ri ii.st sS-ZSi-fJsS" ':| « If arlta sasata rWi*. Sa. Is. . .If ■** t saitak stags alta as*, la. 1* M .It S Msawaf ess* N let si aisled O *s .14 At isSr^'Z**:**: Si m! I mrUmmtm.*wm+mmm.... Ml 4.M t wL*wSa«— MsaMsd At it g3£= ;ii t II fast saaawsttt taMag • 4s .41 JU II fast aspoer sseaasUoi airs It .41 ■aaailat aaawlag details la as- 111.41 111.11 atrial «I1 frets sat has arias aaatagaaaa— MOT III »•••• IUM TTlffi'llV Barnasea sssasrs ««'. Ml 4.M •M raas IfH ease, Ill l.tt jslwags 14— sfcas. 1.71 ll.M Wawara ■Una MM eases IJI lt.ll •lassrlaej atraat detail sf I step ■saaSoat er ragaaaraMss rssslrlac ^ ^ Twa^^jaaawswy 'ik I * awL ""|V '*"M **■'* mtSS IMI SI.M Teases, Ms sal ssatast T-i 11*7 Wired 17.11 ll.M toJBal1 9tt Ifat aVataV M* •Tate** bbVmI I M ifelNa Otafcto wvM saatM al fwtto • tot* r*watatto •* assess. YOU III IT S( PLSASCO. > Radio Parts Manufacturing' Co. JU rmrk PVara Wast Detroit. Mich. D Broadcast Bill's Radiolays By William E. Douglass OC McDOUGALL (he's our dentist) thinks a lot of me; an' Doc, he's wise on sev'ral things besides plain den- tistry. Why, me an' him will sit for hours discussing radio. Course, I'll ad- mit I ain't no whizz but what I'd like to know is how he kin remember all of that there highbrow talk with oscillatin' heterodynes, he beats me at a walk. Not long ago he says to me in kind a brag- gin' way, "Well. Eill I got Havana with my outfit Saturday." He's got a fairly decent set of which he's pretty proud. It took him down a peg when I saz, "Yes, they come in loud." But all the same Doc's waitin' room is strictly up to date, an* while you're parked there in a chair bemoanin' unkind fate, his office girl will offer you a pair of them receiver!. These doctors have some clever tricks (the bunch of "gay deceivers"). She helps -Dw fat ant hi* toab •»" Bay Jaw." you put the harness on, an' then adjusts the phones, so while you're listenin' you can't hear his other patient's moans. Doc says that this new stunt of his keeps 'em from gettin' nervous, and when they're calm an' peaceful he san give 'em better service. The other day my tooth ached so, I thought I'd stop an see, when I went down to get the mail, what Doc could do fer me. I had to wait a while outside before he called me in, and all the time my blamed old tooth wuz hurtin' me like sin. When he began to work on me he sez, "I s'pose you know, my patients always have their choice — some rs or radio." Then, lookin' at the clock, saw 'twuz quarter after three. "Let's get the latest tunes." I sez, "from sta- tion JAZ." So Doc got out his tools an' started diggin' in my jaw. I asked. "How far you goin'?" and the band played "Ar- kansas." "That's far enuff." I sez. and groaned. The set kept ripht on hummin'. Doc lafferl an' sez. "I think they'd ought to play 'The Yanks Are Comin'." Copyright. 1923. Westinghouae Electric 4 Mfg. Co. No Free List Radio World has no free list. The only copies sent out by the publishers are to fill the ever-increasing orders of the American News Company, the large numbers of subscription orders received at the office of publication, and one voucher copy to each adver- tiser and advertising agent represen- ted in current issues. Radio World. 1493 Broadway, N. Y. A Partial List of the Impressive Array of Exhibitors at the ♦American I3AD10 Exposition The Official Exposition for American Manufacturers Grand Central Palaea New York December 21st to 30th Waste** Kaactrto Co., tea. Bastta Car*, sf Aasertra National Parka* Ca., lac. Oiasral lassrlals Case away Far*** Elrrtrtc Csaapaay Del ami Kadla Tel. a TaL Oa» Meaner Kadla Carp nail— C. Beaadaa. lac J. Ilargeaa Darla Davis Radio Cess pa ay Halrbtaaaa Had la Csaapaay Maaafartarera ralrat Csswsaaay Kara Mannfartnrlag Cass so ay Henry Hyntaa a Ceenpany The Haltsrr-Cabex KlertrW Ca. Clapp-Kasthaaa t ssapany Ktrawiberg-Carleen Tel. Mfg. Ca. National Alrpbsns CsrpamtUa DaMlter Csndraerr a Kadla Car*. Aasrrtraa Radia Relay Laaarae Ceto-Coll Casnnaaj rent Karri rtr Cesapaay Copper Clad Sleel Csaapaay Waataa Ksreirlral laatraaaaat Or. Slgaal Klertrlr Mfg. Ca. Srhalra Kadla a Mfg. Car*. Maleno l.rnteaon labarmt irlas Faraslra lawn late Ca. A. H. lire be a Ca., lar. Radio Mien Prod oris Ca. Klertrlr Storage Battery Ca. Kadla otgrat lUaat rated Bargeaa Battery Cssapaay Croalry Mfg. Casapaay Expert aerator P.bllenJuag Ca. Radia ladaatrlra Carp. eVoratt Mfg. Car*, Frri Kadla Mfg. Ca. B*l-Caal* Carp, Tall -Kaa a IMal Ca. Arkrrmaa Braa. Ca., lar. Klertrlral Brrard KipertB>eatrr*a lafaraaaUaa Ssi »lts Ameriran Kadla a Keararrh Carp. Kierallve Kadla Caaartl. lad Met. Natlaaal Kadla Chamber at Caaaaaarx i The Exposition is being or- ganized with the endorsement of the NATIONAL RADIO CHAMBER OF COMMERCE and sanction of the Radio Ap- paratus Section of the ASSO- CIATED MANUFACTURERS OF ELECTRICAL SUPPLIES. For particular* addreMt AMERICAN RADIO EXPOSITION COMPANY IM BROADWAY, NEW TORI TiLirnoKi join ••••

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26 RADIO WORLD R-C CABINETS Nt Drill. Hinged tot. RETAIL PRICES J2.5* 7*14.. 12.7J 7xl«.. 7x21 $4.00 If yw Cteler tenant manly >h, truer dlrect THE R-C MILLS Exewtln Oflloet, SO E. 23d St.. Not V«t. N. Y, (Mention RADIO WORLD) Nalneaaett* PlMStnrnnh asnllty Flnlth lm ef fuwli fir attaching reQulred. 71* 7x10 .»».! .$3.1 Answers to Readers The Latest and Moat Essential Part of an Efficient Tube Set Variable Grid Leak and Micon Condenser (Combined) Obtainable In an nnbrnken rang* free* imrm to 5 megohms— all Intermediate point*. Fixed capacity— .MMnS M. F. Improve* yoar net wonderfully by Clarifying Signals Lowering Filament Current Increasing Battery Life Eliminating Hissing Price Only $1.00 At your dealer* — otherwise send as nnr- chaae price and yon will be ■applied without farther charge. Manufactured by CHAS.FRESHMAN COMPANY, Inc. •7 Bttknan St. New York City Home of Micon A Antenella /S it possible for me to change my set {diagram enclosed) so that I can get further distances without spending money for an entirely new setT — Leslie Roberts, New York City. By putting variometers in your plate and grid circuits you can make your set regenerative and increase your range. This is the easiest way unless you wish to add radio-frequency amplifiers. According to your diagram you are not using any trans- former between your detector and your second bulb; therefore we don't understand how you can get any amplification. * * * / enclose diagram of my apparatus, which consist of following: loose-coupled tuner, crystal detector, and phones. I wish to hear concerts coming from Cuba. Can I accom- plish itt—Alonso Ahe'vrs, New York City. Absolutely not. In order to receive that station, as well as any of the other radio- phone stations located at a distance greater than 30 miles (approximately) from your home, you must employ a* very sensitive bulb set. There are a number of good ones on the market • • * / recently purchased a receiving unit, and, at the advice of the salesman, put a variable condenser in my aerial circuit. When this is turned over a certain spot I get a loud and troublesome click in the loud-speaker. Explain the trouble. — Joseph Turner, Laredo, Texas. From the way in which you explain your trouble it is evident that your condenser is "shorted" (short-circuited). Take the condenser to the store where your pur- chased it and let them look it over and test it out » * * Publish hook-up of set using one stage of radio-frequency, detector, and two stages of audio-frequency in connection with set using RADIO WORLD as a Christmas Gift Have You a Friend Who Is Interested in Radio as an Amateur or a Fan? IF so, you must know that such a Mend would welcome a yearly subscription for RADIO WORLD from you. Sand us $*.M and wa will place the name of your friend on oar mailing list for tha coming year, and also wo will send a special notification to your friend to the effect that RADIO WORLD will be sent for 52 week* to his address with your compliment*. Send in a yearly order, so that the first copy and our acknowledgment of your courtesy to your friend will bo received before Christmas. Address: Subscription Department, RADIO WORLD, 1493 Broadway, New York, N. Y. A SURPRISE FOR XMAS VARI0C0UPLERS 65c Name Send notification to the name given that RADIO WORLD will be sent with my com- pliments (or the coming year. If you wish to send more than one subscription, write additional names and ad- dresses on a sepsrate paper and sdd $6.00 for each addi- tional subscription. Address City and State. Christmas Gift Subscription Blank RADIO WORLD, I4S3 Broadway, New York, N. Y. Enclosed find $6.00 for which send Radio World (52 numbers) for the coming year, 1923, to the following address: With every tn* mis. we will itw a lMek-es far SOMETHING NEW 4-WAY TELEPHONE PLUG Takes the Place of 2 Plugs and a Jneh tt M ANTENNA PLUG Just Attach to Electric Light Nt Her* VT-I W. J. Tjbtt, net* Whs Mas* Aires*; RADIO MAP j LATEST EDITION Featuring: District Divide**, TlaM DMshas, sad All U. S. and Canada Brvtrfuaaa* Osfia 35 Cants Above Map Given Free with SS.oe eurahnat until Xante. All sole* price* in November issue* of RADIO WORLD are good until Xmat. Pottage mutt be included with order. Check* mutt include 10c. exchange and please have them oerti/ted. All good* are shipped P. P. Mew-ad. RADIO DISTRIBUTING & AUTO SUPPLY COMPANY •4 West Mth Street, New York City Phone Columbus SSS4 Broadwar-Tth Avenue Subwar 6th or 9th Avenue L variometers, .vario-coupler, emd 43-plate condenser. You will find a treatise, as well as two hook-ups, in Radio World, No 37, dated December 9, under the heading "Why Radio- Frequency Amplifies Signals," by Donald Van Wyck. * * * / have a two-step amplifying set. When I turn on my second step I am bothered with a howl in my phones and loud-speaker. How can I remedy this T— Charles Peters, Liberty, N. Y. Try putting your amplifying transformers at right angles to one another and shield- ing your bulbs with some light screening (Continued on next page) | -Oondenser* ^Finest 23 Plate.... $1.00 , ..$12$ \f ariometer* $2.00 \/ariocouplers V 14 Tap* A-l $1.25 Phone*— 3000 Ohm* $3.52 Cash with Order RADIO ENGINEERING CO. Fifth Avenue and 28th StrtMt New York Chy My Name Address City and State. 52 Week* for 00.00 Complete Your File of RADIO WORLD Copies of Radio World No. 1 If you did not get a copy of Radio World No. 1, send us $6.00 and we will send you this paper for one year, and start it with our first issue, which will be S ofyordearS ^ "

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RADIO WORLD 27 Answers to Readers (Continued from preceding page) Maybe you educ- made in the form of a cone, are using too much B battery. Try reduc- ing it Don't burn your detector bulb too high. Go over the wiring of your second step to see if you have made any errors. firms selling a cheap phone have tried using German silver; but you cannot get the phones so treated to work, as the internal resistance of both German silver and iron wire dissipate the minute energy in heat. » * * Is it necessary to have an outside antenna for use with a crystal sett How long should it bet— Jerome Llayng, Port Chester, N. Y. With a crystal set better results will be had with an outside antenna, which should run for about 100 feet. * * Is there any law which prevents a woman Instruction Books of the RADIO READING COURSE $1.97 Lam bow to dtsUn. construct, Install, want* and main- tain all kinds of nulla apparatus. Na todies, study. A complete radle eduaatlan. Court* edited and apprered taf Pref. J. H. Marecratt. Up-ta-date. accural*, complete, 8END NO MONEY. Just send jour naaaa and address and pay postman onlj $1 «T and rou awn this nre-bess Radio Library. Write today. Dept. RW4. RADIO COURSES, Inc., $52 7th Av... Now York Defo--'ors KMJ.£B Amplifiers SURPRISED? Everyone la Because WE REPAIR Broken and Bumad-Out VACUUM TUBES Year dealer ihetild km. eat H he dees act, send direct * HARVARD RADIO LABORATORIES Boston I, Mass, Tessa ratsrsed Panel Peat C.O.D. XtV-U* — JLjTlet RaduT Schematic Diagram Requested by Mr. T. E. Limey, Biuuklja. N. Y. Kindly publish diagram of tuned radio- frequency, showing all values. Can a set of this kind be combined so as to incor- porate the units of a regenerative set that I havef—T. E. Livesey, Brooklyn, N. Y. We publish herewith the diagram you request You will notice that we are using two variometers and tuner. If you will refer to the article in Radio World dated December 9 you will find a full treatise, as well as two very fine hook-ups, by Donald Van Wyck. You can use this hook-up as you suggest, but it will necessitate rewiring all of your set, as all the wiring will have to be made as short as possible for the highest efficiency^ , , / have m crystal set, but do not get signals loud enough. Could I add an amplifier to bring them m better f — S. Wolkm, New York City. You could, but it would not be advisable. Why not build a bulb detector and amplify it from that? A crystal is not steady enough. • * • Why emit I use iron wire on a tuning coiif Iron hat more resistance than copper. Are telephones wound with resistance wiref —James Oakley, San Antonio, Texas. It is not resistance that you want, but inductance. This cannot be obtained with iron. Telephones are wound with very fine copper wire. No. 40 is used mostly. Some from applying for a radio license t What is the best type of receiving apparatusf Where can they be purchased f Do I have to apply for a license before I can purchase my apparatusf— Miss A. Wmterbottom, New York City. There is no law preventing anybody, male or female, from getting a license to operate a radio-transmitting station. The only limitations are that the applicant know the laws pertaining to radio, and transmit and receive signals at a fair rate of speed (10 words per minute). The best type of re- ceiving apparatus is a regenerative bulb set Follow the advertisements in Radio World. A license is not necessary in order to operate a receiving station. Radiate Your Home Western Electric (7 AC Phone* ♦ I .9 •> . . „ Speelal Made im- (J. 8. Government with Ear MufMcre and Entra Caea. $6.50 . Speelal Home Charger t14 CA Da Luxe Model J>1J.DU Soeelal Triple Coil Mount- JJ2 95 *"** gpatlal 149 W. 23d Street, New York City Perfection Radio Corp of America SBND CS TOR NAXR OF YOUR RADIO CLUB Also the names of your president and other officers. We want to add those to radio clubs and officers we are preparing tor publication In an early WORLD, l«t* Broadway. Raw York. AETACO We carry a complete lino of Radio Supplies. All sheas of formica panels and tubing. Formica, fZJS a pound. Cut and engraved to order. All sixes of magnet wire and Litxendraght wire. American Electro Technical Appliance Co. 235 Fulton Street (mall orders) 1SS7 Broadway, New York City Our orwelil Prices In the Last laaue of Radio World Remain the Same. Attention ! Fans and Amateurs ! Have you built your own receiver? Are yon experimenting with any par- ticular hook-up? Are yon Improving your set? Are you doing any interesting construc- tive work in radio? Why not than (Ms knowledge with your thousand* of brother font who read RADIO WORLD every toeefcf We want pictures of receiving sets with descriptions of bow you overcame some difficulty, or of any additional part or unit that you have added to obtain better results. These are the things that, prob- ably, the other fellow is looking for. Send in your information; pictures or what- ever you have done to improve the art. Remember the beginner is looking for them. Wo intend to print in this taper, sack week, pictured information and descrip- tion of value to radio amateurs. If you have found a newer or better way of doing anything, don't keep the secret but tell it to your thousands of brother Send m a photograph of your set with or without accompanying diagrams and measurement. State whether you figure in the picture yourself, or not, and with- out any expense whatsoever to you we win make sn engraving sod publish it. Be sure to write your name and address plainly on photograph. Send m your picture at once, or if you have not made a set or done anything else in making radio material, tell the boy next door all about this offer. Address Technical Editor RADIO WORLD, 1495 Broadway, New York City. N. Y. nbithrrlhyf lOOglr

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28 RADIO WORLD DMaauM ar Deaaers tar Btllmkmu RADIO STORES CORP. VARIABLE CONDaTNBBKH— PLt'OS— IUE81HTANCB I N ITS. BTO. If year M> Mil «mr. tWrin Dee*. D. tit Wax J4(> street. Naw Yerk QRM Preventers "BECO" Battle Krrqeraey Beta A REAL DX SET TUN CO TRANSFORMER TVPf tM t» It* Mm t Anal* Frwmw. t Raele rtmon I Vmhb Tata Oeterlar All u » TakM BIRflBM. KXfilN'KKKINO COMPANY lol-le") West *tlh Nireet New Yecji VARIO COUPLERS *GEM $1.25 List FYe mlao mahrn $ other tfylm That List $2.50 up Jobbers — Dealer* — Agents Write far DUcouU Jewell Radio Sales Co. 90 West St New York City Phone bcdr UB> SAVE MONEY ON HIGH GRADE Variable Condensers Direct from Manufartnjrern Taka tba middleman's profit and aall- uuf easts for youraelf. Wa aall 70a St- reet. Theee extremely aeonrata tnetra- menta made by experienced eondanaar paopla ara mlnue tha decoratl»e frllla tbat add ta coat. Price reduced to rock bottom without eacrlnclng quality la the leaat. Satisfaction or your money back. Write today (or very Intereatlnc cir- cular. PRICES: XI Plate $2.55 41 Plate $2.95 deplete wltli Maaatlai Sanaa Year Order Filled by Retarn Mail Mb aaaaka ar ataeer ardaia Beaded. Pay paatana. Read tba ardar TODAY, ana Iodic I la. eaus etaarpa ta aataa ■allies aaat and reaatte year eaa- daaaar m a day ar two. MANUFACTURERS' RADIO ASSOCIATION ; Kinney St. Newark, H. 9. ■^atifr:l'!n:!:r:! That Armstrong Circuit So atach interest haa been dieplayed In tha special article, "TESTED INVENTION OF MAJOR ARMSTRONG AMPLIFIES SET 100.000 TIMES." by John Kent, tbat appeared in RADIO WORLD No. 13. dated June 24, 1921. the sublieher decided to put aside a number of copiea lor those who were not ahir to get thia iaaue when pub- Belied. Copies v - «»nt, postpaid, on receipt •I 15c, or sr 'cription, $6.00, for oae year (52 is nthe. or 11.50 three month • » he started with the leave c< 'bout Major Arm- strong'- )RLD, '493 Broad- way SMALL BOY— "Say, mister, you re- member you sold me a set last week?" Salesman — "Sure, sonny; what's the trouble?" Small Boy— "Well, I put up an aerial outside my window, and I got the wire coming in through the top. Do I have to keep my window open to get signals? It's gettin' awful cold now." * e • One of our subscribers claims he has found a novel way to keep his wife quiet for an hour at a time. It is thjs: Tune in and get the station that is broadcast- ing the latest fashions. She becomes so interested in it that she forgets to ask him why he stayed out so late the night before. * • * Times Have Changed WHERE is the boy — the family pride and wonder — who used to be called on to exhibit to all the neighbors and callers the set that "He made all by himself!" and then would show a table filled with a lot of useless switches, doodads, polished brass, and a score of different knobs? Like the old Negro's horse and buggy, he "jest ain't no mo." In his place you will find the efficient young man who talks fluently about "radio - frequency," "superheterodyne," "CW," and whose set is an efficient re- generative tube-circuit with which he is hearing over half the world. * a * Telling the Beginner ffOUR wires or nothing make your A aerial a matter of pride and not a persona! regret." "Oh, shucks, Charlie, such advice I Don't take a bit of notice. Do what I'm doing, and connect up your set with the springs on m-and father's clock. Sure they work, especially whea the clock needs winding, and- they make the chimes ring." "A single wire is best." "Use two wires at least seventy- five feet long." "It should be at least one hundred and fifty feet long." "The best aerial is an indoor loop." "Why put up an aerial when all you need is a bed- spring." • a * First Night of the Set AND do you really get wireless mes- sages with that thing?" "What's that funny whistle? Sounds like a bird." "How much longer are you going to charge that battery?" "How is my tone?" "This will conclude the evening con- cert." "Vy.QSA hr can hear u all over the house." "Does the lamp light when a message comes in?" "What does all that funny buzzing mean?" "Why do you call him O.M.?" "Why do you turn all those knobs?" "Isnt it wonderful?" "How can more than one talk at a time?" "Guaranteed twenty-five per cent, more power in the aerial. "How do you get me now, George?"— QTC A Record for WGE WGE, "The Constitution." Atlanta, Georgia, was picked up on December 5, by the radio operators of the fleet of destroyers of the United States Navy, cruising off the coast of the State of Washington. The distance is over 2,600 miles, and establishes a record for WGE. tfv.tit.fe GIVE A SPIR°LA CHRISTMAS ! Is? aV a™ ^ ^*WJft»JoUi ."JaV-rta"." !K I alia-freee laaa meeker. SPIROLA* are ' I BETTER LOUD SPEAKERS 0$ REAL CABINET TYPE— n.« lint „ Pnwertul. beautiful. *Mh aa incomparaql e tone •.»."••_ «'.•» ea«tru«tl.a Ihraulnav, .1,' «„ a«.d rVabaT"..".!^" $3.85 il 9mm enclosed In a cabinet. Wt make a complete Ilea .'r."7.j"'k»I rr~ T" *"**"■ ».»■»!, aim ana anna rubbed KnKhe. 8PIR0LA8 ara and have always bean told under money. back guarantee ta aaual In velume and tar aureata In beauty and lone any ether up le twice their , "a SPIROLA DUPLEX-f.r u.a .lib a.y naadaat. Sea.e.t. ton. ,".m. Oak (00) ar maheaaay (DM) (iallk, branled throat TZ°X. co.??col7T.« At. sealers ar postpaid (C. 0. D. K areferrad). II deelrad aa will tend In hollrl.v m^Im you, laatruetloaa. DEALERS-— Wa ... fill "l.d." rush or*.',?'* L. H. DONNELL MFQ. CO.. DEPT. B. BOX 70 ANN ARBOR. MICH. What Shall I Give HER For" Christmas ? most particular about her appearance, can have is Lea Etoils Sltin Food $125 L • Arc • En - Ciel ideal clesneer $1.25 Kantt Face Powder (four ahadee) $1.50 Rouge Superlative $1 00 ieunesse astringent $1.50 farvelous wrinkle remover and cleanser. Amber Royal Perfume $4.00 Eye Laah Grower $1.00 111 .SI Thla entire aaaortment in beautiful Chrlatmae Box will be delivered prepaid upon receipt of $10 Mme. Anita Kanti's Christmas Beauty Box Mme. Kanti'a wonderful preparations have been the favorite for years and used by the famous beauties of both Paris and New York. Among Mme. Kanti's personal clients can be named the reigning stage and screen stars. ABSOLUTE SATISFACTION GUARANTEED Address MME. ANITA KANTI 47 West 42nd Street, New York City Any individual article in this assortment mailed on receipt of price in Digitized by Google

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RADIO WORLD 29 PATENT Tear Radio Ida**. Call or Writ* FREE ADVICE SPECIAL OFFER Par . luaitaa Km «*/ RA-M....M* Crate CM.. $» DA-S ....« Grab. RORK • Fran F.B.B. M Baa*. N. I. A. V. GREGORY N. J. The best SOCKET for the DRY CELL TUBE 60c Daalar* ami Jaabarai Write U» LINCOLN RADIO CORPORATION lit w. Mtk St sfoaa/octiirara Bar Vrr* «t» ViHemtten with dial, tUS Varioaoaplars with dial, $US Far* Paid Moaay Back 4/ BatUtaK. Qautar. TMrd aad taa-laUdi pans at pfapartlaaal* aim. Oa.tna.ra. Baa U.M. 11.41. 0a fan- »t1»» Uaaav !•« 0a ttanaai awa man. 1»% Orrar aad fratanad-faBrjaa tans aada nana aa apvUniwa. Tara*: M ana Nat. t% M ana. CLASSIFIKO AAVUmBKalCMTBr Flra anna at and. BUIaaa. Id aaraa. Ma- araat at It* ra 4 rjaawattra laaaa— 1*% aa M%7tervs5 ,j*j£mam sa^tiSi. mSt Ba an at Hank S. lata. ntFOBTANT NOTaOb .._ .jaa a) at oat aad rata ratard tar lAa oaa. at mum, priarttr at •at at aaaatail •rawaaa, m mm? at artawd a) and What a Real Spider's Web Did RADIO engineers employed by the "Post-Intelligencer," Seattle, Wash- ington, to discover the cause of the er- ratic transmission from that newspaper's broadcasting station finally discovered a spider's web near the top of one of the poles — a spider's web covered with car- bon from soft coal. Swayed by the wind, the web had been swinging against the antenna wires, causing momentary short circuits which bad disturbed the transmission. With Mr. Ehlert's Hook-Up EDITOR. Radio World: — I am getting fine results with the hook-up ot Fred. Chas. Ehlert which you published in Radio World, No. 27, dated September 30. To anyone desiring good, clear con- certs, I heartily recommend this hook- up. With it I have received Havana, Cuba: Washington. D. C; and twenty- two States, including Texas. Iowa, Ne- braska. Florida. Illinois. Missouri, Mas- sachusetts and New York. — T. J. Bow- man. Altavista, Virginia. Tri-Boro Club News THE Tri-Roro Radio Club. Parnassus. Pennsylvania, holds regular meetings at the Lindsay Radio Shop in that city. The members arc working for the wel- fare of the community as well as in the interests of radio All amateurs in the Tri-Boro observe the "quiet hour" from 7 to 10:30 p. m. The officers are: Clyde Hichew. president: R K. Lindsay, secre- tary: C R. Ackltss. treasurer (Ik H0MCHARGEI AUTo"Vr TtADIO B A T T ■ R T Mr a MaaaV FHn. H«-S» BSALa&lWlTi'MVI Aataaaatv*! ■Vrlaaa Oa. INSU-LITE P A N E L 8 t/r Vir—jm mm bb> tmv 1/4" General Merchandise Cm. 1M HarBat Bam I. NawarB. M. t. Simple to Use _ ~ _ M lack eBaa a* kaS- lary lara aa < At King Electric Mfg. Co, Inc. atU nakaara Avaaaa SaBTate, N. Y. FOR CHRISTMAS TVb Uttfo WndV df* m CRYSTAL SET $4 •US UNMOUNTED 2fc HoJUway EUatria Swmp\j Cos, law. *» ™ Aaaaaa Naw Yarfc Ota FRS ALL tfOLDKD DNITKR8AL COMBINATIONS S t'alu to s F. m, B. MaMaa Tart.raHara BB F. WL B. MaMra Tarlaraaalaaa . . . . - aa F. «. 8. MrMrd BaaB WladSaas.. Baak Wiadlnca ara laurckaaaaakle tar dlracl atauatlac aa altbar Vartoaiatar «r Varlocoupl.r. Unlvaraal — * — — t. tntrrtikaataakla A Caaaplaaa Twe-Bla«a Laa« BaaaTa Baaatrn 8»t Includaa two Fadaral Trma.ro Condrnaar. two-moldad Tarlomalara. molded raiiorouplar, thro* V. T aoabata, fllam.nt rh.oaiata. dlala Road *aka blndlnr poaia. awlteb point, la attr lira cablaot and drlllod panal: eompl.tr. roadr to book op. A lit! Radio far $40 F. R. S. Radio Corporation MB-ll Eajrt Fort M. Drtnlt. Mlek. Digitized by Google

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10 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT 5c A WORD RADIO WORLD S QUICK-ACTION CLASSIFIED ADS This department is intended for everybody who wants quick action on short announcements covering the buying, selling; exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that it pays to read these columns every week. Advertisers will get a ten-day service here — that is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy reaches us. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. oer word (minimum of 10 words, including address), 10% discount for 4 consecutive insertions, 15% for 13 consecutive insertions (3 months). Changes will be mad* kt standing classified ads. if copy is received at this office ten days before publication. RADIO WORLD CO., 1493 Broadway, N. Y. C (Phone, Bryant 4796). HAVE YOU SEEN ITT Mr unusual, fully 11- aaHiaisd radio catalog it complete. Saves you moaey. N. E. Ristey, Spring Grove, Mian. VACUUM TUBES repaired reasonably. Saris- faction guaranteed or cost nothing. Vacuum Elects M8, 1621 Derr, Toledo, O. af Wagers Radio Banmhrara ami PATENTS— Electrical cases s specialty. Pre- jrar ehai n " » — 1 ■ 5»" — ■ Lawyer, war charges. B. P. Fish borne. Registered Patent t, 386 McaB BMg.. Washington. D. C Bsialima ImeSosaatara. Rogers y, SIM Wood worth Street, Pittsburgh, Pa. EXCHANGE JOLLY. INTERESTING LET- FEES through our club. Stamp appreciated. Betty Lee, lac., 4254 Broadway, New York City. BOOST RADIO. Wear button. It a pin or button arc progressive. Designs aad estt- . lahed by official dub jewelers. The Raakte Co., Radio Dept., 11U-29 Chestnut St., Philadelphia, Pa. FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO," Write today lor complete list oi premiums and our special sub- scription offer. "RADIO," Pacific BMg., San Francisco, CaL OLD MONEY WANTED— $2.00 to (500.00 EACH paid for huadredt of Old and Odd Coins. Keep all oM money. Send 10 cents (or New Illustrated Com Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave. S3, Le Roy, N. Y. NEWS AND GOSSIP OF THE STAGE— Send He. for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.00 year, $ZO0 six months, $1.00 three months. New York Star Co., 1493 Broadway, N. Y. WE NEED RADIO WORLD, dated April 22 aad August 5. If you have copies you don't re- Ere, mail to this office and current issues will sent you for them. RADIO WORLD, 1499 Midway, New York. DIALS, 3-inch, genuine hard rubber, raised or depressed scale, white or gilt lettering. Drilled (or 14 and % inch shads. 60c. each, J (or $1.50, Kstpaid. No sumps. RADIO SALES CO., Box 14, Bethlehem, Pa. MILLER AUDIO FREQUENCY transformer eliminates howling. Entirely satisfactory on three stages. Price $5.00 postpaid anywhere in U. S. RADIO SALES CO., Box 1144, Bethlehem. Pa. ATTENTION I Yoa invent it. Let us make H. Models, dies, manufacturing. Sheldon Tool Co, Rosedale Station, Kansas Gty. YOUR HOROSCOPE, business, changes, social, matrimonial prospects. Send birthdate and Tea Cents (sumps) for remarkable teat reading. ZANYA, 202- J, West 105th St., N. Y. LOUD SPEAKER FOR ANY CRYSTAL SET. Hear music over entire house. Easily con- structed by amateurs. Eliminates Battery. In- structions complete. 25c. Caulogue Free. Rep- resenutives wanted. STEINM ETZ WIRELESS MFG. CO.. EASTEND, PITTSBURGH, PA. MUST SACRIFICE my brand-new Colin Ken- nedy Universal Receiver and two-step amplifier, including bulbs, batteries, and Magnavox. Guar- anteed over 1,500-mile radius. Bargain at $150.00. Cost $500.00. Cannot ship C. O. D. Robert C Clayton, care of Y. M. C. A, Detroit, Mich. EDISON B. BATTERY UNITS— One positive and one negative plate for 10c 18 sets will make a 24-volt battery. Wilkinsburg Wireless Shop, 711 Penn Avenue, Wilkinsburg, Pa. EXCHANGE LETTERS with friends everywhere. Pleasant pastime. Information for sUmp. Smith, Box. 3125, M. Portland, Ore. EtSEN Supersensitive tested Crystal. Ns> busier teat necessary. If not satisfactory, return crystal and money will be refunded with auiflag charges. Mounted, 50c.; unmounted, 45c Special Prices to dealers. Wm. Hafner, 726 New St, Camden, New Jersey. A VALUABLE RADIO LIBRARY— The special articles in back numbers of RADIO WORLD from April 1 to date, make an invaluable horary of information and reference for everybody in- terested in radio. Single copies 15c each. Any seven numbers for $1.00. The entire thirty-sevea numbers to date for $4.25. Our issue of Oct. tt contains a list of articles published up to that date. Sent on receipt of 15c RADIO WORLD, 1493 Broadway, New York. SILVER MIRRORS-PLATING OUTFITS FUR- NISHED — Stop daily grind. Plant free. Estab- lished 1886. CLARENCE SPRINKLE, Dept. *, Marion, Indiana. WE WANT YOUR NAME— On a postal card. We would like to get the name of every RADIO WORLD reader, as we expect to send out a special message that will interest you. Be sura to send us your name on a postal card and ad- dress it, GIFT DEPT., RADIO WORLD, 14N Broadway, New York. AMATEURS I DEALERS I Write (or list new radio parts. Large discounts. CUNNINGHAM. 280 East 155th Street, New York Cfty. RADIO FANSt Have you read of the won} derful new all-wave Radio Frequency Amplifier invented by Doctor Miller of the Naval Radio Research Laboratory, Bureau of Standards, Waeaf ington, D. Ct We manufacture this device under license. May be added to your present set, giving wonderful results on disUnt station* or may be made up into loop receiver sets will extreme range and beautifully clear reception} for home or automobile use. Besides being the best amplifier on the market, the Miller coven all waves at equal efficiency. Price, $6.50 per unit. Details free. Coast Radio, Inc., El Monte, Los Angeles, Calif. Conference on Radio Standardization of Standards Calls Important Masting to Ba Held in Now York City, January 12, 1923 THE Bureau of Standards of the De- partment of Commerce has called a conference on radio standardization to be held on Friday, January 12, 1923, in New York City. The desirability of call- ing a general conference on radio stand- ardization has been apparent in many ways. This call is issued by the bureau at the specific request of the following associations and organizations: Institute of Radio Engineers; National Radio Chamber of Commerce; Radio Ap- paratus Section, Associated Manufac- turers of Electrical Supplies; National Retail and Dry Goods Association; Amer- ican Radio Relay League; Radio Cor- poration of America. These organizations have pointed out that there is need for greater uniformity in the methods of describing, rating, and testing of performance of radio apparatus. Invitations are being issued to all of the national associations of an engineer- ing and technical nature which are known to be interested in radio standardization. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Please send me RADIO WORLD for please Und enclosed $ SUBSCRIPTION RATES: 1493 Broadway, New York City. months, for which Single Copy Thro* Months Bm Months One Year (52 Issues). .$.U ..1.50 ..3.00 . (Ut Add $LM a Year for Foreign aad Canadian PosUge, The representation of radio manufactur- ers will be through the trade associations of which they are members. While it is desired to make the conference thorough- ly and broadly representative, it is ex- pected that the organizations invited will limit their representation to one or two persons in order that the conference may be as effective as possible. The purpose of the conference is to consider broadly (1) whether a formula- tion of standards for radio apparatus and service shall be made; (2) if so, what general classes of apparatus or service should be included, and (3) what »ro- cedure shall be recommended for carry- ing out the conclusions reached by the conference. If the conference decides that radio standards should be formu- lated, it is expected that they will be prepared with special consideration of the wide range of interests which are con- cerned with the subject, and that these standards may ultimately be adopted with the approval of the American En- gineering Standards Committee as an American Standard. We Want Your Name on a portal wd. We would like to tot the aaaw of every RADIO WORLD reader, as we asset t» •end out ■ iskIiI meense to Mr resdsn. It wig interest you. Be tun to lend s* year sea* ea • postal oard and Kdnu it GIFT D€PT.. RADIO ~ ■*•"• nljitiypH hy

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RADIO WORLD t Choice tea insures restful relaxation! See that your farruly is served more of this superior tea; a golden beverage that has a fragrance and flavor — supreme. Also sold in / lb., */2 lb. and V4lb. TINS will bo sent on reque.t. Add rest I Ridgway*, K, 60 Warren St., New York. "idg&ays COLD MEDAL San Francisco 1915 GRAND PRIZE San Diego &16 Digitized by boogie

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RADIO WORLD DICTOGRAPH I\adio HEADSET 'asW-2 NOW The To A sweeping cut of $4.00 in the price of the Dictograph Radio Headset I endorsement of radio enthusiasts has made possible this sensational red the demand, production has been planned on a new, gigantic scale. Great economies establish the new price — only $8.00. A wonderful bargain I And above all, a wonderful headset— the world' supreme quality for super-sensitive and accurate sound-transmission, The same quality, the same guarantee, the same supreme Dictograph headset always sold for $12.00, in every respect but the price. Type R-l, 3,000 ohms, for all types of receiving sets. THE STANDARD OF THE WORLD 4b4 List Price ITICTOCRAPH RidioLOUD SPEAKER If The Perfect Load Speaker for the Home Public demand baa made peastble the Dictograph Loud Speaker at the low price of only $10.00. complete with t ft. flexible cord. A handaome InatrumeDt that reproduces every eound In crystal-clear, natural tones, full volume, and free from distortion or noise. Ask for demonstration at reliable radio dealers. Get world- famous DICTOGRAPH quality and still save money. Dealers: Order throush your Jabber or write direct for names of authorised distributors. DICTOGRAPH PRODUCTS CORPORATION CM West 4td Street (Branches In all principal cities) New York, If. T. Note: Plans axe now under way for the production of the new 4.0M ohms Dtrtoamph bTPKK-TONS Headset, the meet perfect radio bead eat that can be made. Far the most delicate work, the moot exacting- requirement*. A stew of super-eeaaltlva- sl List price, Slt.M. - Phono-Phane Permanent Include These Items In Your Xmas Gifts! THE giver of Pruden Reliable Radio specialties is remembered a long time. Useful, {practical Christmas gifts that know no equal to the radio fan. The "Pruden" stamp on standard radio parts and accessories, denotes an unexcelled quality and long-time satisfaction. Money back if not more than pleased. Just a few Xmas suggestions shown here. Write for complete list — free on request. This is a Radio Xmas! Dealers, write today for our interesting proposition. FREDERICK H. PRUDEN INC. 993 Bergen Ave. 7$||§f$ra Jersey City, N. J. AJax Hocket Rheostat A device for which amateurs and profes- sionals have long been waiting. Elim- inates wiring between socket and C9 00 rheostat. List eJs..W The only flzsd radio detector requiring as adjustment. Used In place ef ecysts! * vacuum tube detector. Olves oxerHsst quality of sound without distortion, baUsry or tubs noises. Detects telegraph etxsjaa at severs I thousand ml lea. Detects broad- casted music mors clearly than raroun tube detector, and requires no amplifica- tion where the- Incoming signal baa saffl- etent strength to actuate the senattlrt Ideal for use in regenerative Uandsome. substantial, suitable fsr as- sembly In the nnest radio equlprarjt. Guaranteed agalnet Imperfection MSn or faulty operation. Llat each.. Keystone Moulded Variometer laade of a special composition — eatremely llgbt In weight and durable. Ware length ranges from 150 to 580 Meters. Terminals conveniently arranged to afford easy con- nections and avoid crossing terminal wires. Rotor and Blator windings guaranteed not » u»t.«t,.. $5.00 Saturn Automatic Plus The only perfect automatic plus, no need to take apart to make connections. fin* insert i he tertntnali Into the "Saturn" loa a perfect connection Is ma tie. So coa- structt'd that pull inn of the eora> mikM the connection more poaltlre. CI KA Ust each .77.... Digitized by Google

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15c. a Copy December 23 $H°N* Year PADIO WOPLD Be a Radio Booster! Tell Another the Joys of Radio! Make a New Radio Fan This Week! <C. Kadel ft Herbert) David Or gain, thirteen years old, and the prize regenerative »et he built at little cost (S«e ln»i<U for D.t.il.)

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RADIO WORLD mm This Is a Radio Christmas THE DE LUXE U. S. NAVY TYPE RADIO RECEIVER Is The Rolls-Royce of Radio Gives Exact Tuning to Any Distance KNOW THE REAL JOY OF RADIO This De Luxe U. S. Navy' Type Radip Receiver must not be confused with instruments selling for from $200 to $300. Highly selective. Will pick up messages, music, lectures, etc., that lower- priced instruments will not hear. For Immediate $ Christmas Delivery 595 List Price Write for special club or trade discounts CHARLES R. ABLETT C( 199 Fulton St., NEW YORK CITY Detail Description THIS receiver h equipped with binding posts which are nor- mally short circuited for 300 to 6800 meters by which wave lengths np to 23,000 meters may be received by the attachment of loading coils. Capacities of proper loading coils for above are: Primary 50: Secondary 50; Tickler 30 millihenries. While the receiver is pro- vided with a "standby* or untuned circuit, it also has an unusual degree of selec- tivity. Althongh primarily designed for the more ad- vanced fields of Radio work, or the laboratory, the simplicity of arrange- ment and beanty of finish make it unusually desirable for the radio club or tor the individual who desires the finest equipment ob- tainable for his home or office. In the receiver, Bakelite tubes, threaded, provide the forms on which inductance coils of high frequency cable are bank- wound. After assembling, the coils are impregnated with an insulating com- pound, in vacuum, and thoroughly baked. The in- ductance switch controls a mechanism whereby the different section* may be connected, completely dis- connected and opened, or completely disconnected and individually short cir- cuited. This arrangement is important for, by it, each coil has a natural period when connected which is less than the shortest wave length in the receiver's range. The reception of parasitic signals is over- come, the absorption of de- sired signals by the coils is minimized, more energy is forced to the detector and on all wave lengths the interference is reduced. M$&§*$| Will be shipped same day order is received Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered u Mcaad-elua matter. Muck M, at (be Put Office at New York, M. Y„ the act of Marefc 1, U79J A Weekly Journal, PoUUhed Every Wednesday and Dated Saturday, by Henneuy Radio PoMkatioa. Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. VoL II, No. 13. Whole No. 39 December 23, 1922 15c. per copy, $6.00 a year To Catch Every Whisper in Congress (a World Wide Photos) Sound-proof roam in baaemant of the Capitol, Washington, D. C, in which is located the neat remarkable ■peach ampmWr room ia free from all outside waul but no syllable of the lagislathne speakers can possibly escape It. in the world. The THE public-address amplifier-con- trol-room in the United States Capitol, Washington, D. C. A startling title 1 It is in this room that all the speeches in the various com- mittee rooms and clerks' offices are amplified and are carried over wires to any part of the capitol and through outside lines to any part of the country — perhaps, all over the world ! On the right-hand side of the room are the power-speech amplifying tubes and controls, with the loud-speaker above, so that the man in charge of the apparatus may tell if the spoken words are going out without interference. This is the most complete speech- amplifying apparatus ever installed. Up above, on a level with the opera- tor's head, are the complicated re- sistances used to prevent the least dis- tortion of speech. On the other side of the room are the tubes and controls for broadcasting through the agency of the radio station at Anacostia. In order to prevent any mistakes the cir- cuit over which the speech is amplified can either be used to talk to or from any of the rooms. If you will glance at the tubes used on the speech-ampli- fier you will notice that they are com- pletely shielded to prevent outside in- terference. The meters directly over the tubes permit the operator to tell at a glance the conditions along the entire line of wires and apparatus used. By use of anti-capacity switches and jacks he can immediately switch from a faulty microphone to a reserve microphone without as much as loosing a single syllable of "Man of the

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4 RADIO WORLD IMPORTANT progress was made during 1922 in the design and manufacture of radiotelephone and radiotelegraph apparatus both for commercial and amateur purposes. The sale of amateur equipment made a spectacular increase, due to the sudden aroused interest of the public in the new application of radio to broadcasting. The line of standardized component parts which had been originally designed for commercial purposes was later produced for the amateur. Broadcast receivers were built, making use of these parts and a line of sec- tional units, such as the tuning unit, the 3-stage radio- frequency amplifier-unit and the detector-amplifier unit were developed. The main idea in these sets was the production of receivers, each of which would serve a definite function separately, and could also be easily combined. The general tendency in receiving tubes was toward reducing the power consumption in the tube filaments. The first attempt resulted in a detector and amplifier tube using one-fourth of an ampere in the filament ; su- perseding one previously using 1 ampere. Later, a tube using only 60 milliamperes for the filament was equally successful. These new tubes made it possible to use dry cells for the filament excitation and two new receivers were pro- duced. One, a portable set, contains a sensitive tuning system, a detector and single-stage audio-frequency am- plifier. The other set is similar in its electrical char- acteristics to the first one, except that it has two stages of audio-frequency amplification instead of one. N«w Sat* That Receive tr»m Faraign Laada In the line of commercial equipments, new require- ments were met, due in many cases to broadcasting. In one case, a power company sought a duplex radio telephone installation with which it could provide dur- ing times of storm against possible interruption of com- munication between several of its stations seventy-five miles apart. At the same time, signals from nearby broadcasting stations operating on 360 meters were not to interfere with operation of this station on the only available wave length of 400 meters. The set was to be operated through remote control from a desk-stand by the regular powerhouse switchboard operators and to require no attention except that usually given to such moving parts as motors and generators. This set was installed and is operating successfully. For the use of amateurs and for installation on small boats and yachts, there was produced a small radio- telephone transmitter having an output of 20 watts in the antenna. It is built so that it may be operated either from a motor generator set or from a kenotron rectifier which was designed for this equipment. It also may be used on a telegraph transmitter, either con- tinuous wave or interrupter continuous-wave. A new tube attachment for converting spark trans- mitters into vacuum-tube continuous-wave transmit- ter makes it possible for owners of spark sets to realize the advantages of continuous-wave transmission at a minimum cost. It has an output in the antenna of ap- proximately Yi kilowatt continuous-wave and a wave- length range from 200 to 2,400 meters. It utilizes the power equipment and high-potential transformer of the spark transmitter and includes necessary switching ap- paratus so that communication can be transferred from the spark set to the tube attachment. This equipment makes it possible not only to carry on communication with stations now listening in on How Radio Advanced A Record of Progress 2,200 meters, but to carry on communication over much greater ranges with a 2-kilowatt spark transmitter. During actual service tests conducted with one of these transmitters, a range of 1,500 miles daylight, over water, was realized. An aircraft transmitter was constructed for telegraph communication only with a contiuous wave output in the antenna of 300 watts. Provision was also made for interrupted continuous-wave! telegraphy. The trans- mitter was designed to operate from a double current stream line generator driven by an automatic speed regulating propeller. A number of telephone and telegraph transmitters were built for installation on submarines of the United States Navy which include many novel features of con- struction and operation. They are designed for trans- mitting either on the flat-top antenna or a loop, and include a break-in system whereby the operator can listen-in between dots and dashes of the transmitted message. They are available for three methods of com- munication and have an output of 600 meters, con- tinuous wave, in the antenna. The complete equip- ment was extremely restricted in dimensions on account of the service for which it was built. New apparatus designed and manufactured for use with 200-kilowatt Alexanderson alternator equipments consisted of antenna-tuning inductances, remotely con- trolled antenna wave-change switches and remotely con- trolled antenna-variometers. One of the antenna tuning-inductances designed for outdoor service installed at Radio Central Station has a coil composed of ten vertical supports on 82-foot diameter centers. These supports are of porcelain tub- ing, of 3J4 feet outside diameter and are held semi- rigid ly by copper rings on the inside of the vertical tubes. Attached to each of the ten vertical supports are fourteen spacing blocks which are so designed as to provide a maximum surface-creepage-distance between turns. The conductor which is wound in grooves of the spac- ing blocks is of 686 strands of ten mil-diameter copper wire, each strand insulated with enamel. Varnished cambric and treated braid on the outside provide in- sulation and protect the conductor from the weather. The total inductance is 19 millihenries. Ten of these coils were furnished with two 200-kilo- watt alternator equipments for the new radio station near Warsaw, Poland, which is being built by the Radio Corporation of America. Material for four coils of the same general design, except that six vertical supports on 65-inch diameter centers are used, is being furnished for the Radio Cor- poration's station near Bolinas, California. Remotely controlled antenna wave-change switches are to be mounted adjacent to the tuning inductances described above, and will be used to change the num- ber of active turns in the inductances. Ten of these switches were furnished with the two alternator equipments for the Polish station. They will be located at various distances up to more than a mile from the generating station, the point from which they are to be controlled. In the operation of remote controlled antenna vari- ometers for indoor service, means for remote control from switchboard and hand control at the variometer were provided. Digitized by Google

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RADIO WORLD 5 During the Year 1922 By John Liston General Electric Company These variometers are connected in series with 200- kilowatt Alexanderson alternator, feeding energy to multiple tuned antennae. They are used to maintain close adjustment of antenna tuning, particularly when antenna capacity is varied by wind and sleet. Porce- lain supports are used throughout for all parts con- nected in circuit and the conductor is composed of 4,270 strands of five-mil copper wire, each strand insulated with enamel. Varnished cambric and treated braid form the outside insulation. Due to the high-intensity high-frequency electro- magnetic field produced by the windings, no metals of any kind are used inside the windings. The top sup- ports of the framework are of brass. Iron pipes at- tained high temperatures at fractional load in the wind- ings. Closed circuits in the pipe framework are broken up by suitable insulators to prevent circulating currents. The stationary and movable windings may be con- nected in series or parallel. The average range of in- ductances in series connection is .19 to 1.1 millihenries. Maximum coupling averages 50 per cent. A new method of recording and reproducing sound was developed, which is a distinct improvement in many ways over all previous methods used and opens up several entirely new fields of application. It is known as the pallophotophone. There are two distinct devices in the pallophoto- tone — one for recording and one for reproducing the sound — and either may be used independently. The Book Case for Receiving Set By J. R. W., Louisville, Kentucky 1AM sending you what I consider an ideal arrangement for a receiving-set in the home. Sectional bookcases with glass doors keep the set dust proof and give a neat appearance. Many of my radio friends like the idea and, so far as I am aware, this arrangement is original. The large A batteries, bat- tery charger, etc., are in the compartment below— out of the way. Mad* to Hold Receiving Sat, as Described bjr J. R. W. recording device consists essentially of a tiny mirror on which is reflected a beam of light. This mirror is attached to a delicately vibrating diaphragm and when sound waves cause the diaphragm to vibrate, the mir- ror oscillates and the ray of light causes projection of corresponding oscillations upon a strip of photographic film which passes in front of the mirror in a continuous motion. The film is then developed in the usual way and shows a succession of delicate dark markings which constitute the sound record. In the reproduced device, the film passes in front of an arrangement of vacuum tubes which are sensitive to light so that the variations in the light falling on them caused by the lines recorded on the film produce electro- motive force variations in the circuit in which they are connected. Therefore, as the film is moved in this device the electric current is actuated, which corre- sponds with great accuracy to the original sound wave. This electric current can be made to actuate a tele- phone loud speaker or to operate radio broadcasting apparatus directly. The Largest Vacuum Tube aatl Its W easier* Many interesting applications of this new device have already been made and a few possibilities can be briefly outlined as follows: It makes possible the talking motion picture, for on a film of the normal width both sound and action can be recorded simultaneously and projected with absolute synchronism. It is practically unlimited as to the length of record it can make and reproduce and is, therefore, suitable for recording speeches, debates, concert programs, in the taking of evidence and for any purpose where a lengthy record of sound is required. It can be duplicated and used as a film photograph and applied in radiotelegraphy in producing wireless signals and for audio-amplification. It has already been successfully applied in broadcast- ing. The largest vacuum tube ever made consists essen- tially of a water-cooled cylindrical anode 30 inches long and 1J4 inches in diameter. In the axis of the anode is a tungsten filament 0.4 inch in diameter and 22 inches/ long. This filament is excited by a current of 1,800 amperes at 10,000 cycles, the filament excitation re- quiring about 20 kilowatts. The magnetic field pro- duced by this large hearing-current is sufficient to cut off the electric current from the cathode to the anode during a portion of each cycle of the current passing through the cathode, this action taking the place of that of the grid in a 3-electrode tube. The electron current to the cathode is thus interrupted 20,000 times every second. By the use of properly tuned circuits, this may be used for the production of high-frequency power for radio or any other purpose. This particular type of tube, which is called the magnetron, will supply 1,000 kilowatts of 20,000 cycle power at an efficiency of 70 per cent., operating with an anode voltage of 20,000 volts direct current. Complete carrier current equipment of telephone com- munication over the high tension transmission lines of power companies was developed and a number of tests were installed. The transmitter has an output of 50 watts and is rated at 75 miles, provided there are not a great number of "tie-ins" or transformer stations in this distance. The equipment includes a calling system whereby a bell is rung at the station called when the station calling actuates a push-button on the desk-stand forming part of the equipment. Digitized by Google

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6 RADIO WORLD National Radio Week to Be a Big Celebration Over All America THE tremendous contribution of radio broadcasting to the educational life of the country is to be especially emphasized during National Radio Week, to be held this coming week, from December 23 to 30 inclusive. Broadcasting has assumed many roles since its inception, but none has received such whole-hearted and enthusiastic support from the nation's leaders as when it dons the toga of the educator. Sending of operatic arias on the air has become frequent within the past few months. All the progress thus far made in that field, together with a wealth of new material and ideas, is to be assembled during National Radio Week for a grand display. Announcement to this effect has been made by J. Andrew White, chairman of the executive committee of National Radio Week. Mr. White and the committee feel that the broadcasting of the highest type of music not only has recreational value, but is inspirational in home circles as well, and there is tremendous economic benefit to be gained Eminent Radioists Send Their Greetings Through Radio World Around the World in Five Minutes By Edwin Denby Secretary of the United States Navy ■"PHE wonderful development of radio ha* brought pie— ore to millions * «f people. Radio has developed into a great ital agency. Christmas greetings may be sea fat live Minutes. 1 end dspart- the world by A Veritable Public Service By John V. L. Hogan Eminent Radio Engineer and Inventor NATIONAL. RADIO WEEK will give alert dealers their opportunity to demonstrate to the public that radio broadcasting is not a noisy fad for using squawking loud-sneakers, but, instead, a veritable public i capable of placing in the home finer music than can ths phot One of the Greatest Gifts of the Age By General John G. Harbord President, Radio Corporation of America pHRISTMAS Is a season of gitt-givtng and of remembering only the good in Ufa. Radio la one of the greatest gifts to this ago, blessinf mankind with Its achievements and practically marking a new era In the How Season's Indications Point By Paul F. Godley Radio Engineer, Adams Morgan Company, Montclair, N. J. "THERE is no doubt, that the large bulk of business which is bound to * put tn an appearance around Christmas time will more than restore the full confidence of the industry in the future of radio. There still seem to be some people who think that radio has no future. The indications now point to a larger radio business during the coming holiday season than during Ust year, and instead of versing on hysteria, It will be buti- pUced by business men who know exactly Just what the market in educating the American people, through radio, to. an appreciation of the higher forms of culture. Radio's use in the church and school are also to be demonstrated in special nation-wide programs from scores of stations. National Radio Week is an unselfish, co-operative effort on the part of every one in radio, from listener to manu- facturer, to demonstrate what the new science and indus- try has accomplished thus far in the brief span of one year of general popularity and to give the listener an insight into the yet unrealized possibilities of the near future. It is an organized effort to add to the ranks of listeners — to double this number, in fact. The biggest thing the amateur or fan can do is to create another amateur or fan. Building up the already growing army of radio enthusiasts will have a vital effect on the advance of radio throughout the country. Here are a few final suggestions that may be carried out easily to make the big week a smashing success : Humanity Night. In a dramatic way you can allow the Salvation Army, American Red Cross, or any other organi- zation explain the purposes of its movement. This has been done effectively by the playing of music or singing of songs very softly as a background for the speaker. A series of war songs, for instance, played softly by a stringed orches- tra would work an appropriate background for a Red Cross appeal. If an appeal was given for the Near East Relief Committee the music would have an Oriental flavor. . Christmas Eve. A complete Christmas Eve program would include the singing of carols by boy choirs and soloists, who are available usually in every community; stories by representatives of as many foreign nations as you can get, explaining how Christmas Eve is celebrated in their countries; a speech by Santa Claus earlier in the evening for the children ; messages of welcome to the home town by one or two men or women of representation who have come back to their home town to spend the holidays. Contest Night. One splendid contest could be a guess- ing contest Gather together some fifteen or twenty promi- nent people in your city and have them make short talks, but do not introduce them except by number, then have the radio audience send in their guesses as to the names of the speakers to see whether the people recognize their most prominent men or women by voice. Theatrical night, of course, will be a big one. Talent which is appearing at the local theatre should be invited to appear at your station, and not just formally sing a song or two, but to give a "chummy" sort of program for the listeners. Special attention should be paid to children at least two nights during the week. Kolin Hager, of the General Electric Broadcasting Station, WGY, at Schenectady, New York, has been made chairman of the broadcasting managers' committee of National Radio Week. The executive committee, which has charge of all details to "put over" the big radio event, is composed of the following : J. Andrew White, chairman, editor, The Wireless Age; H. Gernsback, editor, Radio News; Arthur H. HaHoran, editor, Radio; Roland B. Hennessy, editor, Radio World ; Laurence Nixon, editor, Radio Dealer; Arthur H. Lynch,' treasurer, editor, Radio Broadcast. Remember ! — The movement will not die on the night of December 30. National Radio Week is to be a permanent national affair. Digitized by Google

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RADIO \VORLD 7 Receives Radio Messages at Over 1200 Words a Minute The 4 the photograph shows • busy corner of th* research Corporation of America where investigations are being made the operation of a high-speed receiver capable of copying tea at a speed of UN words a minute. When signals are sent at this die listener, unless he is equipped with a machine similar to this, will but a steady hum or dash, as at this terrific speed there are, MM "breaks and makes" of the key every minute, apprcori- 1M every second. This is a rate of speed much faster than the ear is capable of catching. The lower photograph shows another part of the extensive research department of Radio Corporation. Here they teat out circuits, kwa- speakers, and other instruments before they are marketed. The illustra- tion shows actually the testing out of five different Innd sneaking in connection with a power, amplifier in order to prove which with the least distortion. This department not only testa materials of Radio Corporation, but any others that seam of particular Importance. Thousand* of amateurs and experimenters would give a lot to possess such machinery and test out apparatus and circuits to their heart'a desire. The man in the dark suit, facing. Is testing out the wave length of various apparatus in order to correctly calibrate and chart thorn. Digitized by Google

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t RADIO WORLD Vast Army of Goods Baptized "Radio" By Washington R. Service WITH nearly every new de- velopment that attains great popular interest, there comes an era of using the new name for, practically, anything else that bids for public support. Hundreds of articles have been christened "Radio." Some products are aptly named, but many have nothing to do with the art or prac- tice of radiotelegraphy or radio- telephony. Twenty-four articles now use the word "Radio" as a trade-mark, ac- cording to the Patent Office records, and still more applications are on file. The first use appears to have been in connection with a chemical compound registered by John B. Daniels, August 23, 1904, about six years before the United States Navy adapted the word to wireless telegraphy. In 1911, the word, "Radio," was registered as a trade-mark for a make of hot-air fans and, also, a brand of varnish and paint. The type and design of the letters in the word were, of course, different, and sometimes the background varied. In 1913 and 1914, "Radio" was em- ployed to designate certain forms of chemicals, medicines, insecticides, leather, threads, yarns, and fur- niture polish. What was probably the first reg- istration of this trade word for an electrical contrivance was taken out for batteries and apparatus early in 1915. A little later, came a type of "Radio" ball-bearing, and, in 1918, the "Radio*' golf-ball was trade- marked. A non-intoxicating bev- erage took on the name in 1918. During the next two years, it was used to designate certain flower and garden seeds, auto lenses, phono- graphs, tires, and a brand of canned fish. The past two years saw "Radio*' applied to watch chains, writing paper, skirt braid, playing cards, cigarettes, and dyes. It was March 14, 1922, before a piece of wireless apparatus was trade-marked "Radio,"although before then it had been combined with .other words to designate many things. Silks, pens, tonics, a magazine, and tea had been branded with the mystic letters. Both "radiofone" and "radiophone" were used in 1920. In 1922, came the terms "super-Radio" and "Radio Rex." Many articles bear the name which seem not to be trade-marked, among them the recently advertised "Radio Boot' — "on and off in a flash." The radio overcoat, with weather-resist- ing qualities, has also appeared. The other day, the name was assigned to a ship which, curiously, carries no wireless apparatus. In the field of sport, the name has been appended to a race horse." "Wire- less," another horse, is also pretty well known. Apparently "Radio" is a popular name, taken by and large, for use in any field ; but there are those who would like to see it confined to matters connected solely with the art. Back-Wound Coils By R. L. Dougherty DURING the past few months the bank-wound coupler and in- ductance coil have come into gen- eral use in receiving circuits. Many amateurs have tried to wind their own coils and have had to give up in disgust after the first attempts. In the first place, bank winding will permit the amateur to wind from three to five times as much wire in a given space as would single-layer windings. Before start- ing to wind a coil the tube on which the coil is to be wound should be slightly roughened with semi-coarse sandpaper. Some firms making bank- wound coils use a base of sandpaper on which to wind the coil ; but this should not be employed by the ama- teur as he is likely to run into diffi- culties and experience a short cir- cuit due to the insulation being scraped off the wire. In Figure 1, I show two types of bank winding. A is a double-bank and B is a triple-bank winding. In A you wind four turns on the tube, being sure to keep a good tension on the wire so as not to have it slip when you wind Nos. 5 and 6, which (see illustration) are wound on top between turns Nos. 2 and 3. After winding four turns on the tube proper, make a bend in the wire and Flfura 1— Hair a bank -wound cod would aapaar If tho coil wan cut In half. TM» fiva* aba a cotnprahanalvc Idas «f tha comet —thod of winding two different types of coils. A la in Illustration of douala-aaak wfaxfias. • of bank wnUauj- C la tha ahujla lajrar, » wind No. 5 between and on top of 2 and 3 ; then No. 6 on top of 3 and 4. Then bring Nos. 7 and 8 down and wind them on the tube, and wind Nos. 9 and 10 as you did Nos. 5 and 6. If you wish to tap off at, say, every fifteenth turn, bring No. 15 down to the tube and make a loop in the wire. Next start in winding as you did before, using No. 15 as No. 1 in the first winding. In illustration B, you see a triple bank-coil. Greater care must be used in winding these as there is more liability of the top turns slip- ping off due to the tension on the wire. The same method should be employed as in A, except to add one extra layer on top. The taps can be taken off in the same manner. Before attempting to wind the coil for use in your set, practice winding Damped Waves By George IV. May, R£. THE radiophone of to-day can- not use the so-called damp wave. The wave trains which quick- ly die out are available for use in sending signals only and corre- spondingly to the action of the waves in water which quickly sub- side after a stone is dropped; or they may be compared to the sound from the piano wire which, also, quickly dies out. • them with some spare wire in order to get the knack of the thing. For the man who wants to know facts, I am giving the inductance values of the two bank windings as compared with a single-layer coiL The constants were taken with coils wound with twenty turns of No. 18 wire wound on a 4-inch core. The diagram is as follows: A — Double bank, 20 turns, 50 per cent, space, 120 per cent, inductance. B — Triple bank, 20 turns, 40 per cent, space, 135 per cent, inductance. C — Single layer, 20 turns, 100 per cent, space, 100 per cent, inductance. Latest broadcasting map 15c That it, a complete broadcasting map appeared in Radio World. No. 8. dated Mar F> Mailed on receipt of ISc. Radio World Company, 1493 Broadway. N. Y. C ( A©>» > Digitized by Google

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RADIO WORLD 9 My Simple Inexpensive Receiver By C. White, Consulting Engineer EVERY field of commercial en- deavor is rigidly governed by two considerations : first, the desire to reach the pinnacle of scientific perfection; second, the desire to meet the capabilities of the average pocket-book. In other words, science and economy form both limits. If we make a certain article too cheap it will utterly fail to come up to the popular scientific standard; if we make it so perfect that its selling price must be high, we challenge the purchasing power of the average man, and cut down the market In radio, as well as elsewhere, these are facts. We actually know of certain circuits that are much superior to anything on the amateur market, yet it would be next to impossible to place them before the public at a reasonable cost. Recently, I have been working out various simple circuits in an effort to produce something that will be very inexpensive, simple to operate, and have definite scientific merit The new method I recently developed to try out new circuits has greatly aided me in getting a good relative value of performance within the narrow confines of a lab- oratory. I briefly outlined this method in Radio World, No. 34, dated November 18. The circuit illustrated herewith in Figure I is generally known as a one - tube superregenerative," or "ultraregenerative" receivers. The circuit is a modification of the com- mon type of single-tube "supers'' in that it uses the inductance of the loop as a tuning element. A variometer in the plate circuit en- ables much finer adjustment than the ordinary type that employs a rotor of a vario-coupler to obtain the same results. The coupling be- tween the two D-L coils should be variable. Since the loop performs the double function as an antennae and a tuning coil, it is quite neces- sary that it be made the proper size. From experimentation, I found that a loop about 3 feet square, having 10 turns, gave much better results than any of the other sizes tried. A 23-plate air variable is shunted across the terminals of the loop; it is recommended, although it is not absolutely neces- sary, to use a vernier attachment of some sort with this condenser if it is desirable to get the maximum results from long-distance telephone reception. A Western Electric V-T 1 tube is recommended for this cir- cuit. In the actual tryout it was the only tube using a low-plate poten- tial that gave fully satisfactory re- sults. This tube requires 4 volts on the filament and 22>£ on the plate; the normal filament current is around 1 ampere. A Bradleystat, or any other type of fine, or vernier- adjustment rheostat, should be used, since this circuit must operate the tube at a critical and efficient point on the characteristic curve. In the actual construction, I advise the amateur to carefully shield the panel against body-capacity effects which virtually result in cutting down the range of reception by making it next to impossible to selectively tune. I would like to call particular emphasis to the fact that this outfit is extremely cheap. It is also equally efficient ; because with quite unfavorable conditions in a steel New Broadcasters Licensed F'LEVEN limited commercial stations > broadcasting on 360 meters were licensed by the Department of Commerce during week ending December 8. WQAK— Appel-Higley Electric Co.. Dubuque, Iowa. WOAS— Bailey's Radio Shop, Middle- towo. Conn. W RAN— Black Hawk Electric Co., Waterloo, Iowa. WPAJ— Doolittle Radio Corp., New Haven, Conn. WOAT— Boyd Martell Hamp, Wil- mington. Del. KFDL— Knight-Campbell Music Co., Denver. Colo. KFDJ — Oregon Agriculture College, Corvallis, Ore. WQAB — Southwest Missouri State Teachers College, Springfield, Mo. WOAU— Sowder Boiling Piano Co., Evansville, Ind. WPAR— R. A. Ward. Beloit, Kans. WOAX— Wolff, Franklvn J, Trenton, N. J. building in New England, i was able to hear Chicago. Of course, it is not the most efficient set to operate. No single-tube receiver can dare claim such distinction ; but, with the man who exercises care in his work, it is surely a set that brings in the distant stations with volume. The only point that would most likely give the average amateur a little trouble is the coup- ling between the two D-L coils which must be carefully adjusted. A good mounting for these coils will materially aid in operation. After a few trials, it may be ob- served clearly that there are certain values and settings that give much better results that others. Learn to tune your receiver carefully and in a systematic, scientific manner. Don't simply turn the dials until something happens. Study condi- ditions, settings and results. Three limited commercial class- B stations broadcasting on 400 meters were transferred from the A list during week, as follows: WHAS — "Courier Journal" and Louis- ville "Times," Louisville. Ky. WLAG— Cutting & Washington Radio Corp., Minneapolis, Minn. KGW — Portland "Oregoniau." Port- land, Oregon. • • • Six New Canadian Stations With the primary object of keeping federal officials in touch with one another six new radio stations are proposed to be erected by the government of Canada. The following sites are mentioned: Fort Smith, Fort Resolution, Fort Simpson, i-ort Norman, Fort Macpherson (all on the Mackenzie River) and Dawson City, Yukon. At any rate, ratio sswm to be tbe eighth woods* of the werU. -SkAitkrCwaDtTk Digitized by Google

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks v.* "*"• % FIfura gram thawta* tha tawU- ibla Una* of tare* mar- r\ESCRIBE an electromagnet ? MB If we take a bundle of soft ■""^ iron-wires, or a soft iron-bar, wind it with concentric layers of wire, and then pass an electric current through it, we will find that we have a magnet. An electromagnet, there- fore, is a magnet only when an elec- tric current is flowing through the wires, whereby it differs from a per- manent magnet. * * * What is a solenoid? A solenoid is a hollow metal tube wound in the same manner as an electro magnet. When a current is run through the tube the wires will, through the agency of magnetism, have a sucking effect on a piece of iron or steel, and will tend to draw them into the middle of the tube so wound. * * * What is the difference between the lines of force in a permanent horse- shoe magnet and an electromagnet? In Figure la we see the lines of force in a permanent horseshoe mag- net, which take the direction shown. In lb, we see the lines of force in an electro magnet. * * * On what does the strength of an electromagnet depend? The strength (attractive power) of an electromagnet depends on two the wire. The more turns of wire wound on the magnet the more at- tractive power it has and the more cur- rent sent through the windings the greater the attractive power. There- fore, if a magnet has 250 turns of wire and 5 volts is sent through it has more attractive power than a magnet of 100 turns of wire with the same voltage being sent through it. * * * What is meant by electromagnetic induction? If we take a coil of wire and place it within the electromagnetic field of an active-electromagnet, and then rap- idly break and make the current run- ning through the magnet, or pass the coil of wire in and out of the magnetic the fa- of fare* Fl*nra vUM* main factors: 1 — The number of turns of wire wound on the electro magnet. 2— The current sent through Flfura 2— Outrun showing how an alactrie cur- rant a> indncad in a cod by tha prinelnb af «lectratnacnatic induction. Tha two cefla an field at right angles, a current of elec- tricity will be found to flow in the second coil. We therefore find that by cutting a coil of wire in a magnetic field we can induce a second current in the wire that is not connected in the original- circuit, as shown in dia- gram No. 3. 6 * * * Show how the lines of force may be determined in a single conductor- current if the direction of the current flowing in the conductor is known? The answer is fully explained in Figure 3. Flfura J— II jrcu gram tha wtan with yw poinna* In tha attraction af tha flaw af tha car- rant, your nngara will foBaw tha direction tnhaa> by tha Bnaa of fares aurroondU* tha wfa*. What is the effect of reversing the current in a single conductor as ap- plied to the lines of force? When the current in a conductor is reversed, the lines of force take the directly opposite direction. As in il- lustration No. 4, when the current is flowing to the north the lines of force flow downward toward the West up and around to the East Reverse the current and the lines of force are re- versed in direction. * * * What is the most important com- mercial use that electromagnetic in- duction is put to? If it were not for electromagnetic induction, electricity, as we have it to- day, would not be so common. This agency when applied to a generator creates electricity. * * * Describe briefly the fundamental principle of a generator dynamo? Whenever a coil of wire rotates through a magnetic field of uniform strength in a manner so as a number of lines of force enclosed by the coil increase or diminish uniformly, a cur- rent of electricity will be induced in the coil, the strength of which, at any time, is proportional with the number of lines of force that are cut by the coil and the speed with which this ac- tion takes place. * * * What are the main essentials of a dynamo? The essentials of a dynamo are briefly: 1 — A magnetic field of con- stant strength. 2— -A number of coils mounted so that they can be rotated in such a way as to cut through a magnetic field. 3 — Means for con- ducting the current induced in the rotor (rotating coils) to an outside conductor. Why the Radio Primer Is Appreciated Extract from a Letter to the Editor of Radio World from E. F. Stettler, Twin Falls, Idaho ' Tory fine pub- FOR almost a year, I bare bean buying at the local newsstands ; licatioa and reading and studying erery issue with a great deal of interest. Whan I first started reading RADIO WORLD I knew absolutely nothing about radio; and although it would be egotistical to say I know • great deal now, yet I do feel aa if I bad a fair knowledge of the fundamentals— thanks to RADIO WORLD." Digitized by Google

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RADIO WORLD 11 A New Application of the Power Amplifier By Frederic W. Procter THE interest taken by amateurs in perfecting their transmit- ting and receiving apparatus has led me to believe that the plan I shall outline herewith will interest more than a few as it lays open a varied field for experimental work. This plan has been put into practice with most satisfactory results and has added greatly to the interest and pleasure to be obtained from re- ceiving. Quite frequently the amateur sta- tion is located in a study and broad- cast reception is desired in the bed- room or some other part of the house ; or the amateur may desire to transmit his own voice, or phono- graph music, from one part of the house to the other. Also, by this plan, the amateur can give his fam- ily the pleasure of listening to broad- casting concerts in the living room of his house without necessitating the extreme annoyance of placing his receiver there. While, in the lat- ter case, the power amplifier is do- ing no more than executing its nor- mal duties it can also be used to transmit audio-frequency impulses other than radio signals as previous- ly mentioned, it being necessary only to connect a pair of headphones to the input, and the distant loud- speaker to the output. The ama- teur should speak clearly and dis- tinctly into one of the phones, tak- ing pains not to moisten the dia- phragm of the phone more than is possible. The actual wiring is very simple. The following only is necessary : Purchase double-twisted insulated wire that will give the two connec- tions needed, and run it under the carpets and doorsills to the point in the house where the loud-speaker is desired, keeping the wires well concealed, and connect them to the two terminals of the instrument. The output of the receiver is con- nected to two of the poles of a double -throw double-pole knife- switch, the other two poles being conected to the headphones for voice transmission, the blades being con- nected with the input of the power amplifier. The output of the power amplifier is connected to the blades of another similar switch, the two loud-speakers being wired to the four poles as shown in the accom- panying hook-up. The principle involved in voice Distmrt low TaOitr-' JwT. . ■ ZntSmttlt Wkt*-- ^* cm fca la amy part at transmission by means of a head- phone is as follows: The telephone consists of a wind- ing about the poles of a permanent magnet, forming a magnetic field which not only includes the pole pieces and magnet but the dia- phragm as well. This leaves two air-gaps in the magnetic circuit, both of which are varied in length by any movement of the diaphragm. There- fore, when sound waves strike the disc, the reluctance of the magnetic circuit is changed and correspond- ing variations of current are pro- duced in the windings when the cir- cuit is closed. Thus it is possible to use the headphone in conjunction with the power amplifier in order to transmit sound over wires to a distant point. It has been found very satisfactory to detach one phone and place it in the small end of a megaphone, supporting the megaphone on a tripod, or some similar standard, so it may be placed before a phonograph should the transmission of music from that in- strument be desired. The mega- phone permits very few sound waves to escape. An ingenious amateur should be able to do not only some interesting experimental work with this hook- up. The author would appreciate a letter, sent in care of Radio World. from any amateur who considered the plan worth trying or made any experiments with the accompanying diagram. Loose-Coupler Set of 14- Year-Old Boy Digitized by Google

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12 RADIO WORLD Radio Legislation Urgently Needed, Says Secretary Hoover Growth of Radio in Past Year, Beyond Expectation. 5999 Amateurs Added in Seventeen Months WASHINGTON, D. C— Ex- tension of the regulatory powers of the Department of Commerce over radio seems im- perative. This is the belief of Herbert R. Hoover, Secretary of Commerce, who has become a sort of foster-father to radio, and he emphasizes that belief pretty thor- oughly in his annual report. The development of the radio art will be greatly retarded, he explains, if his department does not take a hand. The sudden increase of radiotele- phone broadcasting during the past seven months of the fiscal year, from 5 to 382 transmitting stations, and the increase from about' 200,000 to 1,500,000 receiving stations, resulted in so much "interference'' between sending stations, the Sec- retary of Commerce reports, that the destruction of the usefulness of this very important invention was threatened. A conference of experts, manufacturers, and government, public and amateur representatives, which was called by Mr. Hoover in February, unanimously recom- mended the immediate extension of the regulatory powers of the Gov- ernment and drafted a set of tech- nical provisions for submission to Congress. What Ail* the White and Kellogg Bills? Identical radio bills were intro- duced in the two houses of Congress, last session, by Senator Kellogg and Representative White, but appar- ently they are pigeon-holed, await- ing, perhaps, the demand of the radio public itself before any action will be taken. Department of Com- merce officials handling radio mat- ters have cherished the hope that early action would be forthcoming for some time and continued to license all broadcasters every three months, while awaiting a definite law. New legislation would aid the Secretary of Commerce in enforcing the laws and bring about a more satisfactory condition for both op- erators and "fans," they point out. Authority for the appointment of the advisory committee of six gov- ernmental and six outside civilian members, would assist Secretary Hoover in reassigning definite wave-lengths and in the allotment of more bands for commercial and private uses. Congressman White's By Carl H. Butman bill, it is expected, will be pushed, but action is not assured this ses- sion of Congress. Hope for Discretionary Assignment of Wares Recommendations- of the radio conference were for one exclusive governmental broadcasting wave- band, two bands for private and toll broadcasting, and four for use by both governmental and private broadcasters, which would give such transmitting stations broader scope and prevent interference to a great degree. To-day, only two public broadcasting waves are available— 360 and 400 meters — while the goverpment wave is 485 meters, confining a very large amount of matter broadcast by many stations to only three wave-lengths and necessitating time schedules and silent periods. The assignment of waves under these recommenda- tions, as well as other technical problems, would devolve upon the advisory committee. It is very likely that Secretary Hoover would secure the aid of the present Inter- departmental Radio Committee, or at least six of these technical experts as the governmental representatives on his new committee. Another feature planned if new legislation is secured is to make the wave band between 600 and 1,600 meters, now assigned for govern- mental use, available to commercial and public stations. Details such as these, however, it is expected, will be left to the discretion of Sec- retary Hoover. The art of radio is developing so rapidly as to demand constant changes and the permanent or specific designation of every wave or band of waves by law would be a hindrance. Situation Worse To-day Than on June SO Interference is actually far worse to-day than it was five months ago, when Mr. Hoover's report closed at the end of the fiscal year, June 30, 1922. Instead of there being 382 broadcasting stations on 360 and 400 meters, there were actually 565 such stations in operation on December 1, or 179 more than existed on June 30. During the fiscal year, seven commercial transatlantic stations were placed in operation, prqviding for better communication with Great Britain, France, Italy, Japan, Norway, Poland, and Germany. Another commercial station opened for business with Central America, and plans for circuits to South America and China were also under way. In the fiscal year, commercial land stations, excluding broadcast- ers, increased from 161 to 345. Value of the Amateur to the Country Amateur-station licenses increased from 10,809 to 15,504 between June 30, 1921 and June 30, 1922. In the past five months, however, 1,304 more stations have been licensed, bringing the total amateur sending- stations to 16,888 on December 1. The increase in amateur interest by 5,999 is gratifying to the officials of the government ; for, they say, these young men constitute a reserve of trained operators some of whom have already contributed to radio art. During the World War, many amateurs were found to be superior to the average commercial operator in resourcefulness and technical knowledge. The necessity of an international conference on radio communication for the adjustment of international radio wave-lengths, especially those used between ship and shore sta- tions, is pointed out by Secretary Hoover in his report, attention being called to the fact that the last con- ference was held in 1912 when the United States had but one trans- oceanic station in operation. This matter, however, has the attention of the State Department, which is now organizing the personnel of a representative governmental com- mittee to draw up agenda for the next international convention on electrical communication, to be held at Paris next spring. In summing up Mr. Hoover says : "To close an efficient administra- tion of the radio service is imper- ative if we are to maintain its effi- ciency as a life-saving agency on shipboard, a means of commercial communication, and of instruction and entertainent for our people. To perform this work we must have an experienced and expert personnel. To secure and retain such man the service must be provided with adequate funds. Digitized by Google

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RADIO WORLD IS Simple Hook-up Keeps Table Clean By Arthur Hennesly and John Kent Detector Tube A LETTER from one of our readers, Mr. Arthur Hen- nesly, Kansas City, Missouri, contains the accompanying hook-up and an idea that, to us, seems of considerable merit. Mr. Hennesly says: "I have noticed that there are a lot of amateurs who like to try out new hook-ups, and whenever you visit them you invariably will find a lot of apparatus scattered indis- criminately over the table. This looks very messy; besides it is not efficient. "I like to experiment with new Why Is It— fHAT every time yon have oompaay at the house same one who knows nothing ■bent radio will always ask soma question you can't answer and maka yon fsal like a quince tha rsst of tbs evonfag? That every time you buy a bulb, and your Mend la with you and be boys ana, ha always C*ts tha bettor bulb, while you generally fat a -cluck" T That every time yeu want ta nut us aortal, and you have all tha ineUnatkra and time ha the world to do it, it rains? That tha eat worked like a charm In tha atore and you can't even tat a chirp out of It, and everybody in your family gives hie er her advice as to Just what the trouble la, and you dent even fat a chance at It till everybody else la dU- wtth -that fool thing"? That people Insist on thinking of radio and ii holms aa two different and distinct things? thinks ho has evafvsd aa original idea which bo hook-ups and have solved the prob- lem in this way: I make up the tuning unit, detector unit, radio- frequency amplifying unit, and audio-frequency units in separate cabinets, with all the connections brought to outside binding posts that can be conveniently bridged with small pieces of copper wire". For the main connections I use jacks and plugs. It Is a simple mat- ter, therefore, to hook up any desirable tuning unit with either radio-frequency or audio-frequency and the table always looks neat and businesslike. "Another advantage is that after having built a radio-frequency unit, or a detector unit, and tried it out you know that it works and how it works, so that when you hook it up you know just what results to ex- pect. I am enclosing a hook-up to show how it is done — in Missouri where you have to show ate." This is a practical idea. Besides its neatness, it is an instance which proves that the everyday amateur is getting down to the serious bus- iness of real work and is not playing with a lot of radio apparatus just to pass the time. Don't Miss Him! Santa Onus Will Be at WGY During National Radio Weak 1-TELLO up there! Is this Mr. Santa ■*• A Gaus ? How do you do, sir ! This is radio station, WGY, speaking. Suppose you're awfully busy just now? . . . Too busy to talk to the thousands of little people here in the U. S. A., who will be counting on you on Christmas Eve? . . . Yes, sir, actually talk to them ... all of them at once, too! What's that, you say? . . . Never got such an invitation be- fore? Wouldn't miss a chance like this? That's fine, Mr. Santa Claus! Then let us tell you what we've got in mind." Yes, boys and girls — big and little, young and old — that is part of a conversation that took place the other day over the private wireless-telephone of WGY, the General Electric radio station at Schenectady, New York, with Santa Claus himself as the other speaker ! And here's wHat came of hi Santa Gaus is actually going to talk to you by radio! To all of you — that is, to all who are able to listen inl And not only one night, but every night for a whole week, from December 18 to 25 inclusive I Think of thatl And here's an even bigger surprise t — It's for the same week! Santa Claus if going to introduce all of you to another member of his household, someone who hasn't ever been heard from before! It's the vivacious, jolly little step-daughter of the whiskered saint— it's Mary Christmas! And Mary Christmas is also going to talk by radio to all youngsters on the three last nights of the same week, December 22. 23, and 24. She's promised to tell just what she does in Santa Claus House— how long she's lived there and what she thinks about Santa Gaus and. especially, about boys and girls I A special program will be given by WGY on Christmas Eve, December 24. There's a particular reason why Santa Gaus and Mary Christmas will give talks by radio during the week of December 18, to 25. Of course it's Christmas week. But it's also National Radio Week, when for eight nights steadily more than five hundred radio broadcasting stations alt over the United States will give special programs of novel features. Digitized by Google

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14 RADIO WORLD Radiograms The Latest Important Radio News Briefly Told for the Growing Army of Radio Fans WGY, broadcasting itation of the Camaral Electric Cm- panr, Schenectady, Naw York, has btsa heard ia every State ia the Union. Although programs have been regularly sent from this station for the last nine months, two states — Idaho and Nevada — had not been heard from until a few days ago. Because of the great confusion caused by so many stations operating simultaneously, only such replies naming artists and the time heard which accurately check with the WGY log, are con- sidered. The greatest points reached in all directions are: West.— Oakland, California, 2550 miles; Kingman, Arizona, 2175 miles; Enterprise, Oregon, 2170 miles; Hillyard, Washington, 2150 miles ; Midas, Nevada, 2200 miles. In a special test, WGY operating on its experimental license 2X1, has been heard at Hilo, Territory of Hawaii. North. — St. Johns, Newfoundland, 1075 miles; Calgary, Alberta, Canada, 1950 miles. East. — By a steamer, 2017 miles in the Atlantic ocean. South. — By steamer "Luckenbach," 150 miles south of the Panama Canal, or a distance of 2450 miles; Mexico City, 2150 miles; San Juan, Porto Rico, 1700 miles; Pela, Honduras, Central America, 2000 miles. a a a Arrangements to establish a university extension course for the people were made between the Society of Radio Artists and Audiences and the Lecture Bureau of the New York Board of Education whereby selected lecturers broadcast tabloid lec- tures from the WHN station, Ridgewood, Brooklyn, New York. * a a Another chance for DX fans I Daily transmissions of teleph- ony from Konigswusterhausen, Berlin, are on a wave length of 2,800 meters, and the times are 6 to 7 a. m., 11 a. m. to 12:30 noon and 4 to 5:30 p. m., middle European time. a a a Disabled men will get radio for Christmas. Members of the auxiliary of the Bill Brown Post at Sheepshead Bay, New York, are devoting considerable time to the welfare of the disabled veterans in the Manhattan State Hospital on Ward's Island. Through the efforts of this auxiliary the men will be presented with a radio set on Christmas Day. Mrs. Mary E. Hartt, presi- dent of the auxiliary, arranged with several of the members to conduct card parties and social functions for the purpose of raising the money necessary for the purchase of the set. The* complete outfit will cost $450. a a a Former Postmaster General Frank H. Hitchcock, who is de- voting much of his energy to the wonders of radio these days, was the guest of honor at a luncheon at the Bankers' Club, New York, to some of his old friends connected with New York newspapers, a number of whom are now writing on radio subjects. Others who edit the wireless departments of papers met him for the first time. The luncheon was given by L. S. Byers, executive secretary of the American Radio Exposition, of which Mr. Hitchcock is president. a a a One of the radio subjects recently discussed in Chicago and Minneapolis was a broadcasting policy designed to initiate and support broadcasting programs of the highest type. In this connection it is proposed to enlist the active cooperation of the public press, educational institutions, boards of trade, churches and, what is of utmost importance, to obtain the active cooperation and assistance of the users of listening apparatus, whose rapidly growing investment in radio equipment makes them greatly concerned with the proper maintenance of broad- casting. a a a Mr. and Mrs. Samuel Franklin, of Lansdale, Pa* Mr. and Mrs. H. L. Shellenberger and daughter, Mis. Ethel Snellen- berger, recently heard the voice of their son and brother transfitted through the air from a distance of 1,5M miles. The singer is Charles Shellenberger, former baseball pitcher at Ursinus College. He is now hoys' secretary at the Denver Y. M. C A. He sang at a radio concert in Denver. When Mr. Shellenberger, Sr., who is assistant cashier of the First Na- tional Bank, received a letter from his son, stating that his solo would be broadcast from Denver, the father made ar- rangements to "listen in." The singer's voice was heard as if it came from an adjoining room. a a a A marriage performed by radio is illegal, according to a con- struction of the Domestic Relations Law by Attorney General Newton, in New York State. The words, "in the presence," in the law mean an actual and not a constructive presence, the Attorney General held. The question was raised by the pro- posal to have a San Francisco clergyman broadcast the ritual to contracting parties in Grand Central Palace, New York City, the bride and groom broadcasting their responses. a a a The sixteenth radio station for the Air Mail-Service has been put in operation by the United States Post Office Department, a a a It is nothing new for the Boy Scouts to use radio apparatus. Various troops long ago made and purchased receiving instru- ments, and even before the advent of broadcasting the scouts numbered among them some well-known radio amateurs. Now that broadcasting is here, however, they are finding new fields for the use of the radio. Instead of using it only for their own instruction and recreation, as they virtually were compelled to do in the days when only code could be heard, now they are placing it before others who need to enjoy the radiotelephone but for obvious reasons are unable to do so. New Noninterfering Detector by H. P. Donle HP. DONLE, radio inventor and experimenter, after years • of research and the building and study of thousands of bulbs, has developed a new vacuum tube. This tube is an ex- ceedingly sensitive detector. Without regeneration, Mr. Donle claims it gives responses as loud as a good regenerator using the usual grid form of tube. Used in a plain circuit, it cannot produce interfering oscillations; it consequently should be strongly welcomed in broadcasting circles. Mr. Donle's tube is known as an intensifying detector. It contains no grid. One form uses a short straight filament above which is supported a trough-shaped collector electrode. Under the filament is a main anode consisting of a piece of metallic sodium. The best circuit is shown in the diagram re- produced herewith. The action of the tube involves controlled ionization and a peculiar construction which gives not only ex- treme sensitiveness, but stability of adjustment. This tube has been tried out Its sensitiveness in a plain receiver, if anything, is claimed to be a little higher than that of a good U-V 201 in a high-grade regenerator. It is also claimed that they are incapable of radiating so as to produce interference. At the meeting of the Institute of Radio Engineers, held at the Engineering Societies Building, 29 West 39th street, New York City, on December 20, Mr. Donle described the new tubes and showed them in operation. 4 ~1 ri ■f Mr. Denis's as* tab*, traaga Digitized by Google

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RADIO WORLD Radio and the Woman Crystal D. Tector Tunes in with a Variety of Radio Topics on Matters of Interest to the Gentler Sex DID it ever occur to any of the young women reading this department that a number of you who are talented could apply to the broadcasting station in your vicinity and be heard over the air? Just imagine what your friends will say when they hear something like the following being broad- cast from station XXZ: "Miss So and So will now render a •election from 'Traviata'? Miss So and So is one of the grow- ing number of women radioists." Wouldn't they just die of envy? And look at the publicity you would get at the next meeting of the Neighborhood Sewing Association. • * * 1 WONDER why the Hairdressers' Association doesn't put up a resolution to change the term, "permanent wave," to the up-to-date radio term, "continuous wave." Imagine their ad- vertisements then — something like this: "Continuous wave. Guaranteed by the latest methods. Only $50.00." 1SEE where those French hussies are trying to get their names in the paper all the timet Their latest lad is to carry a parasol with a receiving set in the handle. Well, we'll have to go them one better. What modiste is going to be the first to name the "Chapeau Radio"? Then we could listen to the broadcasting while shopping with one of the latest creations on our heads. • * * FRIEND HUSBAND tried to pick a quarrel with me the other morning — in an entirely new and original way. He said that I forgot to turn off the filament current on the set! Imagine that, when I distinctly remember that he was the last one to listen in. * * * AT last the neighbors have stopped borrowing my phones. I designed a plug that won't fit their set, and they can't use them any more. ♦ * * AND I have also hit on the ideal way to make the wash- woman hurry up. Mine happens to be colored; and, like many colored folks, she is slow. I took my loud-speaker and put it near the kitchen door, turned it on, and, as luck would have it, WGI was broadcasting a particularly lively jazz. It worked fine. She had the wash done almost an hour and a quarter earlier, and remarked when leaving: "Dem dare radios sure do put lots of pep into a pusson, missy." • * * T ' VE a surprise for you. Of course, you mustn't tell anybody •*• that I told you this, but there is a big hairdressing establish- ment in this city that is going to have a radio set in it with a loud-speaker in every booth so that everybody (men included) who ask to have their permanent wave developed may have something to listen to besides a lot of shop talk about hirsute adornment I know this will be a treat; because, from my experience, I am fully convinced that I know more about the care of the hair than any four hairdressers put together. * * * I WENT radio bargain-hunting with a friend the other day. Just as I was entering the radio department my friend spied some imported lacey house-dresses at a really astounding price. Well, Friend Husband will have to wait for those vernier rheostats until next week. It really would have been a shame to let that oppor- tunity go — don't you think? * * * AN anxious mother writes me that since a certain little boy — "Johnnie" — acquired a new set as a birthday present she has trouble getting him to bed at night, and that his excuse is that all the long-distance stations don't come on until after the local broad- casters have closed up. She wants to know if this is so and if I will advise some remedy. Well, I am not sure; but, as the young man seems to have acquired the habits generally attributed to "night owls," the only remedy I can suggest is to let him sleep all day so that he can listen all night As you probably know, a "night owl" is generally incurable, and it is but wasted time on the part of certain physicians to insist that every one needs at least eight hours' sleep each night A "night owl's" inherent determination recognizes no doctor— only his own desire to get the most distant points possible. And, of course, from what I have heard, this is most probable in the "wee sma' hours." QRM Preventers By Patrick Nichols Quizzes and Queer Remarks a Ham MUST Hear! WHAT does that thingamajig do?" "Can't you get an opera on?" "Why isn't PJX on to-nightf" "I came over especially to hear Havana." "Why is a spark station?" "Won't you teach little Willie the code. He's such a bright boy, I'm sure he will learn quickly?" "Say Bill, let's try this hook-up, Willyar" "Why ain't it working?" "Can you show me how to do it?" "I've got a friend out in California. Can you connect me with him?" "Is a wireless wave anything like a permanent wave?" "Can't you make it any louder?" "Surely, you didn't make it all yourself. I can't beiieve it" "Does it come through the air?" • * * Radio Hams We Meet THE fellow who goes "up in the air" when you sit down to his set and disturb the pet adjustment that took him all of one-tenth of a second to make, and then goes around threatening to lock up his set so that no one can touch it. Aughl The first hundred years are the hardest! You get used to them by that time! * * * Signing Off! IF the rheostat offers resistance will the lightning arrester? If the battery gets "charged" will the crystal detector? How can I stop WJZ from coming in so loud. If we'll all have to learn to talk French when we get in daily communication with Parisian amateurs, or if they will have to learn English? » * » Famous Sayings of Radioists I'LL get this thing fixed to-night or bust it so no one elsell ever fix it." "I'm not kiddin' you! Fact, I heard him say PWX as plain as I hear you— and on the loud-speaker, too." "I don't know — it never did this before." "Oh! I haven't any time for girls now; I'm building a new set." "And the funny part of it is, I didn't have the aerial connected." "Say, did you every try—?" "Oh, say, have you just discovered that? I used to do that back in 1913, with a crystal set." * * « Has It Ever Happened to You? *TPHE night was cool, the moon was full, ■*- not a cloud was in the sky; The folks sat round the radio set— to get signals, he did try! The folks had come from out of town— best type of country cousin; But the dad-blamed -on ery-j unlc — he couldn't even get it buzzin! And needless to say that inside of an hour he had every piece of apparatus out and back again, and couldn't locate the trouble until the morning sun showed his aerial grounded. * * • A Boy's Work Description of R*ff«B«rativfc Rocolvwr oa Radio World Front Cow, This Waak THE photograph on the front cover of this issue of Radio World shows how Young America is taking up radio. David Or gain, a youngster of thirteen summers, is photographed putting the finishing touches on a single-circuit regenerative receiver of his own construction. You will notice that he is using the familiar hook-up in which the rotor of the coupler — which, by the way, is bank wound for reception up to 3,000 meters — acts as the tickler. While the panel is made of wood, and there is nothing elaborate about the set, it is certain that when it was finished some good DX work was done on it. Digitized by Google

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16 RADIO WORLD (C. "P. ft A. Photos") (Abore) The human voice photographed. A new dories known aa tha paHo-photophone baa boon partaetad by Charles A. Hoxia of tha Cansral Electric Company, It permits the photo- graphing of the hnman voice and reproducing It, not aa • picture bat aa the actual sound of itself. A reproduction from the Hade machine was declared perfect after several It is retarded aa tha apparatus which will make talking merles a successful reality and has Introduced Into radio broadcasting an entirely new element— tha possibility of making; a master record from which copies can be made and reproduced m the four corners of the world. Mr. Haxle (at right) is shown demonstrating tha machine and inciden- tally taking an indelible lasting record of the voice of the man standing before the reproducer. (C. Kadel ft Herbert) (Above) A loud-speaker with the aid of your electric heater. Try this and see if ft doesn't 1 a fine loud-speaker. Take your electric heater and place your receiver aa shown in tha photograph. You will be surprised mt the results. It may be carried out with en old dish pan or any parabolic metallic object large enough to throw the sound. If you desire to use the heater, be sure that you don't turn on the heat, or disastrous results may ensue. You will have to do a little ezperhnenting to find the best location to bang the phone so that it will threw the sound, as simply hanging it before the heater will not do. It is best, perhaps. If om the hearer or when placed almost before Its canter. Only experimenting the m re of all heaters and dish pans you havs to take into consideration ■r-ront thicknesses of the metal used. Late Noveltie Radio Week! the Phol (C. Wide World Photos) (Above) Room shore the Great HsU of the College of tat I concert given by the Philharmonic Orchestra was trsasnui of the American TeL and TsL Company. L.ft to right: Cd D. Robmaosa, director is chart Digitized by Googli

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RADIO WORLD 17 s for National Recorded by jgraphers (Akn) Tha m» radio broadcastina station hi Ik* baasmant of ttx Capitol ml tha Uaitod States, Washington. D. C, which broadcast thm Presl- daaf s speech before Coaaress recently. Thie is the first Una as history that the general pub- lic haa baas abla to bear a President i Coagnaa. This Is ana of tha ana* Improvements that haa boan made ia tha Bald lately, aa it practically pate tha Executive at tbla great nation hi personal tench with aD (Right) J. H. Ridley, teat room oparatoi of dept. Ltd., Blachhaath. ancinaars of who whO* tear station* talkhuj to ana i ool ai I hi tha first time This is that ia America mm Eaaiand Rldlar at his (C. Wide World Photm)

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IS RADIO WORLD With the DX Night Owls Who Can Beat This ? EDITOR, Radio World: I am not claim- ing a record, but I have all those beat that I have seen. I have a home-made regenerative set, with two-stage amplifier, using honeycomb coils. Can't be beat! I hear WGR, Buffalo, New York; KDKA, Pittsburgh; WSB, Atlanta; WMAT, Duluth, Minnesota; WOC, Davenport, Iowa; KSD, St Louis; WFAA, Dallas, Texas; WBAP, Fort Worth, Texas; WEAY, Houston, Texas; KDYX, Hono- lulu, Hawaii, and enough stations in moun- tain and Pacific time districts and in Canada to run my list to over a hundred stations broadcasting concerts. Let's hear from some one who has this beat. — N. E. Parr, Albany, Oregon. * * • Get Your Knees Wet EDITOR, Radio Would:— 'With the dia- gram of connection I enclose, I have done some remarkable work. I can get Newark (WJZ) almost every night. Out here we have some very funny weather at times — that is, so far as radio goes. Some- times everything will breeze along fine. Then, the same day, you won't be able to get anything worth talking about They don't seem to fade; they just don't come in. At first I thought it was my set; but by comparing notes with a couple of other amateurs around town, I find that they have the same trouble. I have put a variometer in series with my coupler. Although it is not absolutely necessary to the circuit, I find that it gives me much sharper tuning. I am using a home-made coupler modeled after the all- wave, and I'll say that bank winding is no cinch. This hook-up is very selective and you have to get used to the tricks 6f it before you can get any definite results. With this circuit working properly and a good clear night, remarkable work has been done by a number of fellows out this way. In tuning this set, you have to get used to using the rotor of this coupler as a regenerator. On some stations, this is rather tricky because where you may get one station at 10 de- grees another on the same wave length may come in around 160 degrees. I have over- come this to some extent by the use of the variometer and the variable condenser in the opi. Schematic design of Mr. Jack Lyons, Tucson, Arizona, who ■fans himself "Grand -daddy ml Nlgfct OwU," sad . Tka Editor, af RADIO WORLD wffl ba pleased to raeoiva sketches of hook-up* af the various "DX Nlfht Owls" sandinc hi records, with a visw af publishias than. Other letters from tka DX "buss" will ha published from week to weak —The Editor. secondary circuit. I find that it works well without the secondary condenser; but, as the variometer, it all tends to make the tun- ing more selective. With this hook-up and a fairly soft tube with variable B-voltage (which, by the way, is very necessary) I have no trouble in bringing in WJZ, WGM, and a score of others. "Step up and get your knees wet with this one I" is my motto. Come on you DX boys. — Jack Lyons, Tucson, Arizona, "Gran- daddy of Night Owls." • * * An Idaho Record IT DITOR, Radio World: Having noticed ■Lj in a recent issue of Radio World that a radioist in Chicago had been getting un- usual results I wish to submit my report When using but one old-type Cunningham audiotron with an inverted-L aerial 45 feet high and 110 feet long, directed to the east, I have heard the following stations : KFAF, Denver; KDYL, KZN, Salt Lake; KFI, KWH, Los Angeles (KFI every night for a week) ; KLP, Los Altos, California; WBAP, Fort Worth, Texas (very clear music at about 7 p. m.) ; KFV, Yaking, Washington ; KFZ, Spokane, Wash- ington; KGO, Portland, Oregon; WHB, Kansas City, Missouri, and Calgary, Canada. Close tuning is done with an aerial con- ductor and a grid conductor. — Kenneth Jones', . Blackfoot, Idaho. * * * Connections Not Soldered EDITOR, Radio World: I am sending my receiving record of the -past month. I am using a home-made set built by a friend and myself. None of its connections is soldered. It con- sists of a vario-coupler, variometer, 43- plate variable condenser, and two stages .of amplification. The first record I want to mention I received on my inside aerial which is 32 feet long. On this aerial I received WOC, Davenport, Iowa; KBAP, Fort Worth, Texas; WHB, Kansas City, Missouri, very plainly. The stations that I have received on my outside aerial, which is 100 feet long and 25 feet high are as follows: KZN, Salt Lake City, Utah; KWH, KFI and KHJ, Los Angeles. KHJ has been received so loud I have heard it all over my house on a King amplitone. WBL, Anthony, uaoS Mr P Kansas, also very clear. WHB and WDAF, Kansas City, Missouri; KFBB> Havre, Montana; KFAA, Dallas, Texas; WOI, Ames, Iowa; 6XB, San Francisco, and KSD, St. Louis. I have received also the following stations in Canada: CFAC, Calgary (very plainly): also CSCN. Calgary; CJSC and CJCD, Toronto; and CJCG, Winnipeg. Here's hoping I soon hear KDKA and WJZ, and then I will be very much sat- isfied with my set. — George C. Franz, 268 South Clarkson Street, Denver, Col- orado. a » a From Troy, New York EDITOR, Radio World: I am using honeycomb coils and three tubes with jacks. I noticed the records in Radio World. Here is mine: WNAC, WDAP, WOS, WDAF, WSO, WLB, WHAS, WGR, WAAH, WIN, WEP, NOF, WJAX, WHB, KSD, WGM, 9XN (9XJ, WRM), WSB, WDAF, WWJ, WOC, WOH, KYW, KDKA, WLW, WBR, WEAK, WPO, WRB, WRS, WUR, WAAP, WNAO, WHAG, WWI, WMAM, WSP, WNG, WSC, KYS, KOW, KDOC, KDOS, KDOW, KDKC, KDBC, KDA. WDOD, NNE, NNK, NOM, WHAL, WBA, WAR, KWZ, WDAK, POZ, WBAD, and WDAP on November 9, 16, 19, 28, and December 4. I have a large number of other nearby and distant stations including amateur. The ARRL call, November 30, was heard at noon. No call number was1 received. Wireless on ships and land at a dis- tance of 1,500 miles have been beard. — E. B. Missenger, Route 3, Troy, N. Y. » » a Doesn't Claim a Record EDITOR, Radio World: Having read the various records set up by different radio "bugs," I thought I would send in mine. I don't claim a record as I have pals here doing the same thing every night, but I do think I have Mr. Merktein beat a little, as I am 75 or 100 miles farther northeast I hear the fol- lowing station with a home set: WOC, Davenport, Iowa; KSD, St. Louis; WHB, Kansas City, Missouri; WOS, Jefferson City, Missouri; KYW, Chicago; WGAS, Chicago; WDAP, Chi- cago; WMAQ, Chicago; WLK, Indian- apolis; WHAS, Louisville, Kentucky; WWJ, Detroit; WJAX, Cleveland; WDAJ, College Park, Georgia; WSB, At- lanta; WGM, Atlanta; PWX, Havana, Cuba; CKAC, Montreal, Canada; WGR, Buffalo; WHAZ, Troy; WHAM, Roches- ter, New York; WLW, Cincinnati; WNAC, Boston; WGI, Medford Hill- side, Massachusetts; WBZ, Springfield, Massachusetts; WGY and QXI, Schenec- tady, New York, and a great number in Philadelphia, Washington, New Jersey, Pennsylvania and other New York sta- tions.—Herbert L. Wheeler, 10 Lincoln avenue, Milford, Conn. Station 1 BUW. a a a 32 Stations in 2 Hrs., 45 Min. DITOR, Radio World: December 4th, _ beginning at 8 o'clock p. m., I started in to see how many phone sta- tions I could get on my home-made re- generative set, using only one bulb. At exactly 10:45 o'clock, I had heard and listed 32 stations. I listed them as I received them. It must be remembered Digitized by Google

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RADIO WORLD 1< With the DX Night Owls (Continued from preceding page) .0005 23 Tarns on T/ck/er 1 SO Turns on Prim. No Taps Used- ' .0005 No Leak Usecf^z .q005/tfCor?a. £ ' 2000 Ohm / Phones 7s s TV 6Voffs i of Mr. Bart A. Wrigkf • hookup, A Workrit. coupWr la dmxL Tho ' U Tory critical. A ▼arnior may bo used to wwhwui and minimum. All tuning la done adVantaga. Tho tuning that this was accomplished in only 2 hours and 45 minutes. Other stations were still coming! in when I quit No doubt this number would have been increased from 5 to 10 more, if I had set up later. I had a list of 125 phone stations that I had heard at different times. It has been almost two months since I last listed in it. I was getting so many stations I did not take time to make a record of them all. Listing the 32 stations was not diffi- cult. I have received stations from al- most every State in the United States, also Cuba. My hook-up is my own, so far as I know. I am giving it here for other owls to try out. The closest sta- tion received on December 4 was 90 miles. Come on and wade in, DX. — Earl A. Wright, Cole Camp, Missouri. * * * Good for Dry-Cell Set EDITOR Radio Wokld : I have a "pea- nut-tube" regenerative set with no amplification. Since November 25 I have heard distinctly Minneapolis, Chi- cago, Atlanta, St Louis, Kansas City and Denver. I consider this very good for a dry-cell set My set is something like Mr. William A. Bruno's set in Radio World, No. 30, dated October 21. I also use the 22^-voIt B battery. I use a vario-coupler bank wound with 150 turns, 11-plate variable condenser, vernier- filament rheostat, grid condenser, grid leak, and W-D II aeriotron tube. I in- tend to add one stage of amplification and note the results that follow. — J. E. Bradley, Justin, Texas. » » * 6BNQ Tunes In EDITOR, Radio World: In Radio Wokld, No. 36, dated December 2, Mr. E. Sherow, New York, claims the record for 1-tube DX reception. I think I have him beat. Here is my list to date: WBAY, New York City, good; WGY, Schenectady, New York, faint; KDKA, Pittsburgh, good; KOV, Pittsburgh, good; WSB, Atlanta, Georgia, good; WOC, Davenport Iowa, loud; WOI, Ames, Iowa, good; WHB, Kansas City, Missouri, good; WBAP, Fort Worth, Texas, good; KLZ, Denver, Colorado, good; KFAF, Denver, Colorado, good; WFAA, Dallas, Texas, good; KOB, State College, New Mexico, good; KZN, Salt Lake, loud; KDYL, Salt Lake, loud; KFBF, Butte, Montana, good; KDYS, Great Falls, Montana, good; KFBJ, Boise, Idaho, good; KGG, Portland, Ore- gon, loud; KGW, Portland, Oregon, good; WOAI, San Antonio, Texas, good. _ This is not the complete list-^only sta- tions over 400 miles away. My receiver is a home-made Grebe CR-5 with de- tector only. The aerial is 35 feet high and 50 feet long, 3-wire inverted L. Please publish this and give other "bugs" something to think about. — Merle Schill- ing, Opr. 6BNQ, Box 297, Beaumont, California. Timely N. R. W. Hint EDITOR, Radio World:— Could not the broadcasting and amateur sta- tions be pressed into service to advertise National Radio Week? May I suggest that you mail a few letters along this line to start things going. I am for Na- tional Radio Week and do not want to overlook anything that will help the good cause. — R. C. Connor, 931 North Fourth Street, Camden, New Jersey. Why Magnavox is the Reproducer Supreme OFFICIAL tests with the oscillograph prove that the Magnavox elec- tro-dynamic receiver re- produces incoming wave forms with maximum ac- curacy. The Magnavox can be used with any receiving set — the better the set, the more Magnavox can do for you. When you purchase a Magnavox you possess an instrument of the very highest quality and effi- ciency. R-2 Magnavox Radio with 18-inch horn (as illustrated) This instrument is intend- ed for those who wish the utmost in amplifying power ; for clubs, hotels, dance halls, large audiences, etc. It re- quires only .6 of an ampere for the field. Price $85.00 R-3 Magnavox Radio with 14-inch horn The ideal instrument for use in homes, offices, ama- teur stations, etc. Same in principle and construction as Type R-2. Price $45.00 Model C Magnavox Power Amplifier For use with the Magna- vox Radio and insures get- ting the largest possible power input. 2- stago $ 80.00 3- stage 110.00 Magnavox products can be had of good dealers every- where. THE MAGNAVOX 00. Oakland, California N. Y. OMen sn Sanaa* An. Digitized by Google

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30 RADIO WORLD Latest Radio Patents To Detect Minute Values of Energy Earl C. Hanson and Wendell L. Carlson Put Hetero- dyning to Important Use 4 jo zr Figure 1 shows dlagrauunaticaUy the Invention utilised tor tho reception of radio -ig»-i» Figure 2 shorn tho Invention adapted for wmiirlug tha luminosity of a source of light No. 1,437,240, Patented November 28, VOL. Pat- entees: Earl C. Hanson and Wendell L. Carbon, Now York City TWO of the foremost radio ex- perimenters in the United States have been granted letters of patent on what seems to be an entirely new method of detecting and amplification of radio currents — an invention to provide suitable apparatus for detecting slight variations * * Kills Undesired Oscillations No. 1,437,«21. Patented November 28, US. Pat- entee: John C. Schellong, East Orange, N. J. AN invention to prevent vacuum tube systems from generating undesired oscillations. It is particularly applicable in the case of radio-transmission systems utilizing electron discharge devices hav- ing plate, grid, and filament electrodes for transmitting electromagnetic waves of high power. In such vacuum tube systems, espe- cially systems comprising a plurality of high power tubes in parallel, troublesome oscillations of undesired frequencies often occur. In many instances these oscilla- tions are ot a frequency much higher than the frequencies normally used in signaling. These undesired oscillations often result in failures to operate at the in the frequency of an oscillating current. The fundamental principle on which this invention is based is the "heterodyning" of two or more oscillating electric cur- rents to produce a beat, the frequency of which will be determined by the natural constants of the circuits and the external influence of an interference acting upon one of the circuits. * proper frequency, or in the capricious alternation of the frequency from one value to another, particularly during modulation. In some cases, these exceed- ingly high-frequency oscillations man- ifest themselves by periodic or irregular variations or phenomena which occur at lower frequencies or irregular periods re- spectively. In certain cases, waves or impulses occur of such frequencies as to produce audible sounds which are espe- cially objectionable. These high-fre- quency waves may cause excessive differences of potential between certain closely placed parts of the apparatus. Where undesired oscillations occur as a result of a cyclic transfer of energy through several tubes, it may be possible to prevent these by including inductances in the circuits of one or more but not of all of the tubes. Hence from a broad aspect this invention is not limited to the use of the inductances in the circuits of la Figure 1. Reference character I designates a tuned iwUe-frequency antenna-circuit, which le eegpled te the reeeaaat circuit L Tha thermionic vacuum-tube amnnfier % ha* Us burnt ooa- drcult Z and its output connected to tho input winding 4 of the well-known magnetic every tube of a parallel group. The use of the words, "plate, grid, and filament" in describing the elements of discharge devices are to be understood in their gen- eric sense as referring to anode, control, and cathode electrodes of any form and construction. It is to be hoped that if this system of Mr. Schelleng's comes into general use; it will allow more powerful stations to operate at a closer wave-length range without causing the interference that is now so noticeable. * * * Pictures by Radio No. l,4M,«7f. Patented, November a. U22. Pat- entee: Magna Hermod Petersen, Christiana, Norway MR. PETERSEN'S invention is in- tended for the transmission by radio of pictures, writings, or other similar matter. In this device, part of the current circuit of an alternating cur- rent generator connected to the transmis- sion leads is short-circuited by means of a contact arrangement, which is so actuated by means of the writing at the sending station, that the short circuiting is started or interrupted by means of a contact needle passing over the written lines. His method is also adapted for solving the wireless _ synchronizing problem. The inventor claims that by his method of transmitting photographs by radio, perfect detail is maintained and that, according to the advance in radio- photography it has been the most difficult phase of development in the new science, to perfect. How to Buy WHEN you decide to buy an auto- mobile, you don't just go out and buy the first one you come across. Yon look at a number of them and then decide on the one you think will give you the best service for the money you spend. Then, why do you buy radio goods and sets just the opposite? Don't take the first thing that the salesman offers you and then be dissatisfied and grumble about getting "stuck." Buy radio goods as if you were buying a motor-car. Determine just how much money you can afford to spend — and then get the best set you can within your seized by Google

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RADIO WORUXL Hoover May "Control the Air" He Asks for That Power in Appeal from United States Courts Order to License New York Radio Company ON another pace of this issue of Radio VVoblp, Mr. Carl H. Butman, our Wash- ington correspondent, contributes a timely ar- ticle based on the suggestion of Herbert C Hoover, Secretary of Commerce, that radio legislation is urgently needed in the United States. This action may be stimulated by a suit just filed in the United States Court of Appeals. Washington, D. C It seems that after having its hands tied for over a year, so far as the regulation and the con- trol of radio communication between the several States and foreign countries are concerned, the United States Government has begun a fight in the Court of Appeals of the District of Columbia for a decision which will place Secretary Hoover in "con- trol of the air." On behalf of Secretary Hoover, District Attorney Peyton Gordon and Assistant Dis- Radio Compass Uses S tumid Thar* Bo Aaothar War, It Will PUy mm Important Part RADIO compass receivers, it is claimed, will be instruments of great importance in warfare. Any radio transmission of the enemy's fleet for example, is subject to re- ception; and if so received, the direction from which it comes can be determined and the approximate location of the fleet, or ship, determined. For this reason it is prac- tical, in war time, to keep the amount of radio traffic at an absolute minimum, using it only when absolutely necessary and then restricting the power used to that required for the communication carried on. The radio compass may be used also for locating hidden radio-transmitting stations on land. As in other branches of science and en- gineering, the practical application of radio compasses has been accompanied by a num- ber of difficulties and has required an enor- mous amount of research and development work to perfect a working system. This work has centered mostly on determining the type of transmitted signals which lends it- self best to accurate bearings and to means for improving the calibration of the compass receivers. It has been found, for example, that the calibration, even of a fixed station with no moving objects nearby, it not per- manent and must be corrected from time to time. The compass receiver usually has more amplification than the receiver operating on a flat-top antenna, since the voltage gener- ated in a loop is usually less than in an an- tenna. The directive properties of a loop, are applicable to forms of reception other than compass work, ar.d are frequently used for ordinary radio-reception work in vicinities where there are a number of transmitting stations. Rotating the loop makes it possi- ble to secure maximum signal-strength from any one of a number of stations, provided they are not on the same line. That Armstrong Circuit bii been dtiplared Id th« INVENTION OP ET 100.00S RADIO So much intent! asocial article. "TESTED MAJOR ARMSTRONG AMPLIFIES Sr TTVES." by John Kent, that appeared in WORLD No. U. dated Jane J4, 1922. the publisher decided to pat aiide a number of copies lor thoee who were not able to get thi a i»ue when pub- ■•hod. Copie* will be aent, poetpairl. on receipt of lie, or tend in your eabecrlptioa. 1600. for on* rear (12 ieeaca). 13.00 tin montha. or SI SO throe atoatfca. and enbecription will be atartre! with tha leeae containing the article a boat Major Area- •trong'i Amplifier. — RADIO WORLD. «W Broad- way. trict Attorney Vernon West argued that Justice Wendell P. Stafford of the District of Columbia Supreme Court had erred in compelling Mr. Hoover to renew the license of the Inter-City Radio Company, Inc., to operate a high-powered commercial wireless station at 110 West Fortieth Street New York City, and also to fix a wave length at which the company might operate without interfering with messages from nearby sta- tions. The license of the Inter-City Company expired on September 22, 1921, and Mr. Hoover refused to renew it acting on the theory that the law vested him with discre- tionary power in that respect Complaints had been made by the radio communication services of the Government and others that it was impossible for their stations to send or receive messages while the Inter-City plant was working. The appellate court took the case under advisement BCM BROADCAST RADIO RECEIVER mmj people live hi lorn Moan where ■ •Hal la laapaaalhla. Other* ebjart « pnahn being auathrared by pole mm4 wire*, aad aaaay teaM I beer ablUt to operate arte with each rani nlb-a ileal RNailaate theae frataree by beta* I C I Radio PVeqaesey BraaaVaat receive** aa> Dealer* thould write BCM RADIO COMPANY YnJLANTI. MICIL Don't overcharge your is as bad as letting it charging. battery. That stand without Quality, Deetpn . WorrnwiiuMp afolerial = RELIABILITY Simple to Ut knny 110 e. I lamp nock ftacb clip* to bai iecr— Hire on cui rent and yoaj bai yoor own cba>| A ceatpect portable *U*b*igta*j ' win ratty « *araa a MS AH batbary i lor Sc. b* Mc At year goaion or writ* Kjm Ehctric Mil. Celiac. DELICATE SOLDERING Both the manufacturers' and amateurs' problem on all 1m work la raadUr solved by tha uutrument constructed for this particular purpose. THE POST SOLDERING IRON Platinum Heating Unit — Interchanceabl* Tip — Universal Corrwat Half Artaal Sane $6.00 From Your Dealer or WrlU Awarded Certificate of Excellency. N. Y. Evening Mail Radio Institute POST ELECTRIC COMPAW, (Dtv. Mt) M E. Oa4 St, Mew Tit THR ONLT GENUINE AND GUARANTEED "All Wave" Coupler TftAOS MASK 0 Meters FLAT AMD BANK WoUbO Wave Length, 150 to 3,00 a* aa« Uedto* Catb. Inae- aalt tb» laaeUaai a - tba aw at 40 Tarle tnurh a It I mblneo. EWRttH than Ontaea rtf •_. SJaaata Tv* aSlrtaet heat-are eta** trm ottb eaab "an 9m 1 n*wi*»aj roui'irr **»«waa tat tiwma nmiaa mi attain ib« mm naaal •lulMd br tha tipan In bulkSn* lha atsplaal. null* ranl'lrt a*t pawibla. laPrtairatJ- lacrnaalne nwa»ear. Unstnl Results Attain. For thr hlrhw war* bturthj allottari I* braailraatlna ata IiriLD a art thai aannot Intll'iibHl ann* at lh» "*l Wife" One* m nan "vmMrr ua that In Rboda lafeAd It U neOilae taniuual u brine la auuona aa tar aouib aa Haraaa. Cuba, abil* la Moaiaa. Alabama. Naoaia. N J . bt bnmfht In dall>. a th» "All ««.»•• ravpiar. able* la ream an ad wita a ohw»*t ba't to srmu aa Mit*ml—& Laa* far lha All Wat*." aa lb* mar. aba lha all afftelaet baae-oa la I - Btwara ef Imitatimn rk-ltrv* awTTJt with nrh ■AJt Wm~" Of IOr. Caaplrr •tQ f\f\ enVlrat II *P%S •\J\J atampe ar Fr» UlAKANTKED WITH AN AB TIIOI aANIIS O Capitol Phonolier Corporation UlAKANTKED WITH AN ABaOl.l'TK HOSfr-Btri Gl'AKAnlM tiioi aAMia or aATianrn ra««* I tjatayelte at raw Now Torh OMp •sin ra tup: hkmu OF YOUR RADIO CLUB Aleo the nameo or rear preeJdeat and ether offlcera W* want to add tha radio elvba and efflcera w* ar* preparing far publication In an early I WORLD, less Broadway. New Tee*.

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22 RADIO WORLD Advertising Kates, Display, $5.00 per inch, $13000 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Sustain Radio Injunction Superior Court Reaffirms Decision to Stop "Bad-Faith" Radio Advertising THE Appellate Division of the Supreme Court of the State of New York has confirmed the lower court's decision grant- ing an injunction to the Freed-Eisemann Radio Corporation in its suit against the Wireless Specialty Apparatus Company. The injunction was sought to prevent the Wireless Specialty Apparatus Company from advertising and circularizing certain state- ments made in regard to radio patents. This decision has a very important bear- ingi and is the first step in the solution of a great many patent tangles resulting from the sudden growth of radio.. Interesting developments are expected as a result of this decision in connection with the claim of the Freed-Eisemann Radio Corporation for $150,000 damages, alleged to have been suffered by them as a result of the patent warning advertistnenta inserted in various papers, and in restraint of which the injunction was granted. Business Is Fine RADIO business is quite normal. It is the large number of retailers, manufacturers and jobbers that make conditions bad, says "The Mail," New York. The situation may be compared to the large number of thirty men standing about a good sized pail of water. Although the pail is large enough for ordinary purposes, there is not enough water in it to go around. As a result some of the thirsty ones remain thirsty. As the sifting down process of the radio industry continues the time will come shortly when there will be plenty of business for those who are able to last. The industry is simply adjusting itself. Although the retail trade is picking up splendidly, the good effects have not yet been felt by the jobber and the manufacturer to any great extent. After the Christmas period perhaps the manu- facturers will get their share. A Condenser for Superaccu- rate Tuning THE Hammarlund Vernier Condenser wu de- signed by experts and is manufactured by a concern twelve years in the business. The pat- ented vernier-control moves the rotor plates by as little as 1-S0th of a degree on the condenser scale, and is arranged to eliminate all inter- ference due to bqdy capacity. It is therefore possible to get on the exact wave necessary to receive at maximum efficiency, without the least interference from other stations broadcasting on the same wave length at the same time. Its construction is so ragged that capacities at given settings always remain constant, making it impossible for it to get out of calibration, even though abused. The plates are the Bureau of Standards straight-line wave-length type, most suitable for wave-meter work. The ca- pacity increases at a uniform rate and makes the most critical adjustments possible. The plates will withstand the high voltage used in transmission work and cannot become short-cir- cuited. The Electrical Testing Laboratory certifies an insulation resistance of 15,000 megohms, min- imizing leakage and power loss; a phase differ- ence of less than .01 at 750,000 cycles; and a aero capacity almost too small to be measured. Fifty-two issues for f&OO. Smb. De- partment, Radio World, 1493 Broadway, N. Y. C. New Firms and Corpora- tions (The Arms md corporations ■ the** eohmmu cm be reoehed by cemnmm eating with the attorneys, whose oMresset ore give* whomever possible.) Hause Battery and Auto Electric Corporation, Jamestown, $20 000; F. E. Roth, F. E. Hause, G. H. Zillig, Jr. (Attorney, W. B. Grandison, James- town, N. Y.) Alcon Electrical Supply Company, Manhattan, $7,100; J. H. Lyons, E. Dimin, H. Driscoll. (At- torney, S. B. Cardozo. 30 East 42d St., New York.) Westchester Radio Distributing Corporation, Mamaroneck, N. Y. E. R. Lemanquais Company, Plainfield, N. J., electrical engineers; K. N. Lemanquais, Harold Lemanquais, E. Ross Lemanquais, Plainfield, N. J. General Electrical Protection, Brooklyn, burglar alarms, systems, $5,000; E. S. Depaaqnato, B. Alexander. (Attorney, P. L. F. Sablatino, 291 Broadway, New York.) Oranola Radio Corporation, Wilmington, Del., manufacture talking machines, $1,000,000. (Cor- poration Service Co.). G. & G. Electrical Corporation, Glens Falls, contractors, $10,000; S. and W. L Ginsburg, A. A. Goracoff. (Attorney, J. McPhillips, Glens Falls, N. Y.). . Baion Electric Corporation, Wilmington, Del., mechanical and electrical apparatus, $500,0001 (Corporation Trust Co. of America). Crowther Electric Company, 310 Main Ave., San Antonio, Tex. Electric Fixture & Radio Corporation, 234 Sixth Ave., North Nashville, Tenn. Incorporators: A. F. Anderson, Tom C. Sharp, E. M. Hudgins. Qeartone Radio Supply Company, 5 Laura St., Providence, R. L Albert E. Proffitt, prop. States Radio Corporation, Wilmington, Del., manufacture radio, ' $30,000. (Corporation Service Co.). Reals tuff Radio Company, 8815 Lane Avenue, Detroit, Mich. Weld Square Radio Shop, 46 Weld Square, New Bedford, Mass. Frank S. Sousa and R. M. Rus- sell. Edison Electric Appliance Company. Inc., 412% Stark Street, Portland, Ore. S. G. Stuart, pro- prietor. CHANGE OF NAME The Etna Radio Company, New York, has changed its name to Herald Laboratories. CAPITAL INCREASE Electric Specialty Company, Fairfield, Conn., (25,000 to $250,000. Coming Events The editors of RADIO WORLD publish news items of all •a. gladly mailing full information. SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, inclusive, 1923, George A. King, director of publicity, 417 South Dearborn Street, Chicago, HL PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. AMERICAN RADIO EXPOSITION. Grand Cen- tral Palace, New York City, December 21 to 31. Colwell & KorbeU. Fisk Building, New York City, directors of publicity. SECOND DISTRICT RADIO CONVENTION, Hotel Pennsylvania, New York City, March 1, 2, and 3, 1923. FIRST UNIVERSAL EXPOSITION OF IN- VENTIONS AND PATENTS, Grand Central Pal- ace, New York City, February 17 to 22, inclusive, 1923. Heard at Radio Counter A Conversation Between Customer ai Radio Clerk (Part VII) "| HAVE a crystal receiving-set to know If I can cosrrart tula i sat osnpioymg a vacuum tabs as a detector/* "Yes, sir. Yen certainly can do so. But tol me what method ml inductance you ara using; namely, tuning coil, loose coupler, or vario cou- pler." "WelL 1 bsUavs I am using the as It has a primary and i operating an anal out of the primary on a brass shaft," "You ara comet fat your assumption that it is a loose coupler. With this luuss coupler you can connect up s vacuum tuba vary nicely." "Just what tubs would you rscaasmoad with this loses coupler 7** "That is a hard question to answer. Let mo ask you Just what vacuum tubs you ] You know there ara two Idndst the six- volt , age battery tubs aad the sea dry-cell tuba." "What is the "The difference is this! One tuba -. six volts supplied from a storage battery; the "What Is the effect en each tuba so far a raCGptlOU Ot? SiCamtilS aS COIaOaVTllsfam T** "Wonderful results have been obtained either of those tubas, the differaaco being the •UminarJon of the troubles oca. storage-battery necessary for the six-volt tuba." "Well, on that advice, I guess IH tabs tha dry -call tubs." "Very wall, air. Here you ara." (.To be continued) VARIABLE CONDENSER 23 plate Variable Con- densers. Genuine brown Bakelite ends. Heavy Aluminum Plates. All brass parts nickel plat- ed. Complete with Knob Dial and Pointer, $1.75 Cash with order. E. J. ROBE 620 W. Monroe St. CHICAGO, ILL. AETACO German set, complete with WD-11 tube and A * B battery. A special at. .* UN Federal Phones Standard Variometers fLM «B» Batteries, MV» volts Me A Maputo lias sf Cearles Fresaasa Ce. presorts tlvayi Is ristk. Vsrlaels Srld-lssk sag Ossdiaisr. F train panels cut md drilled Is erase at leuest priest, American Electro Technical Appliance Co. MS Fulton Street (mall orders) 1,»7 Broadway New Tar* City

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RADIO WORLD 23 Answers to Readers DECENTLY I constructed a one-stag* radio-frequency and detector set, but cannot get as good results or as loud signals us when I used a detector and one-step {audio). I am not using audio now. What is the matter t— J. Shack, Brewster Corners, New York.- You do not enclose any data as to just what you are using; but you will not get any appreciable amount of amplification, if any at all, from one step of radio. The ideal radio-frequency is a tuned two-step radio-frequency detector and from one to three steps of audio. Radio-frequency makes distance possible mainly by clearing the signals up before they are detected, a • • What is the best type of storage B bat- tery for use in a receviing^ set {Grebe re- generative) t Where can it be purchased f — O. Christensen, Philadelphia. We cannot recommend any specific type of storage battery, but suggest that you write to storage-battery manufacturers for their literature. * * • What are the W-D 11 tubesf Are they as good as the regular radiotronsf Can I use these in my set {Portaloop; Z-step radio-frequency, 2 audio) f— Charles Boukes, Muncie. Indiana. The W-D 11 are now known as the \%- volt tubes. They do not require a storage battery for their operation, a single dry-cell being sufficient. They are exceptional de- tectors and good audio-frequency amplifiers. They cannot be used as radio- frequency am- plifiers; so, if you intend to utilize them in your set you must rewire the filiment cir- cuits or else put sufficient resistance in the line for detector and amplifier so that not more than 1J4 volts would flow through the circuit * • • Give me a diagram showing how to hook up the following apparatus: Vario-coupier. variometer, AZ-plate condenser, 3 tubes, 2 transformers, A and B batteries.— Edwin O. Uhlig, Richmond HiU, N. Y. If you will refer to the hook-up in Radio World, No. 32, dated November 4, in "Re- ceiver for Amplifying Weak Signals," by Horace Beers, you will find a diagram suited to your purposes. It will be necessary only to place the variometer in the position of the coil marked Tickler," in order to ac- commodate your apparatus. It is not neces- sary to have three separate B batteries. You can connect them together and tap off at 22H volts for the detector, the other lead of the remaining 45 going to your amplifiers. * • • i./r?m^ building superregenerative set, lSH-s- Potter, described in Radio World No. 31, dated October 28. What are the best tubes to use in this circuitf Should I use a detectm and amplifier, or two ampli- fitrsf—D. WQkes, Washington, D. C. The regular U-V radiotron are the best tubes to use in this circuit, as it is rather critical. A detector and amplifier are sufficient. * * * wound with 60 turns of 22 S. C. C, on the rotor. Could I incorporate this in the 2- tube superregenerative described bv H S ?0,%,n3*»10 w«u* No. 31, dated Octo- \Z . f, m lg-,nch loop work with I %%,ho?? turns "»« be neces- sary f W41 thts loop be directionair—M. W Rowell, East Orange, N. J. As this circuit is very critical, it is not advisable to change any of the windings to anything except explained by Mr. Potter in his article. It will be necessary for you to rewind the rotor and stator of your coupler. Make sure that the outside diameters of both are the same as that stated in the article otherwise you will not get the results that can be had with a set of this type. The 96 turns are on the rotor. It is very im- portant that all instructions regarding the construction of any part be followed to the minutes degree. If you wind about 10 turns of wire on this loop, it will work satisfactorily. It will probably work on a smaller loop; but this is not advisable, as then the tuning is sharpened too much. When the loop is pointed in a direction, the signals will be received best from stations directly in the plane of the loop. * • * Is it necessary to use batteries in con- junction with an Aeriola, Jr., crystal sett I can't tune between WJZ and WEAF when they are on together, like other sets I have heard, but hear both at the same time. — "Radio," Brooklyn, N. Y. A battery would be of no help in a crystal set. Your trouble is characteristic of all crystal sets. A crystal set cannot tune as sharp as a bulb set and, therefore, you are able to hear both stations though there is a difference in the wave length. * * * I intend to construct a small regenerative coupler-set. I understand that I must use bakelite tubing, on which to wind my coils, for best results. Is this soT I have received satisfactory results from my tuner wound on a cardboard oatmeal box. — Jerry -Hecht. New York. While bakelite is a much better insulator than cardboard, it is not necessary to wind your coils on bakelite. Ordinarily, cardboard tubing shellaced and left to dry so that it will not warp or shrink, is sufficient. RADIO MAILING LISTS 1 2.400 Ml* Dwltrt, swsrtaf 0. 8. 1.014 R*7k Mfrv unriH u. T Tj ... to Arte pwlrtt. IS.N !!! SSfi* ■ Vi -MrH*. *M tI7 Mir*. ok* asks sad iwakU wa- .. ... _ ')!** "*"• •»*• Mr Hit. 4.10 26,000 RUU AMtoan tmi Nuassn tf JN**» StatlMt par M, 7.M A* ftr arks IM* tar Casta*. Caolsa*. rtW llrta. ntAOB CIRCt'LAR ADURRfWINU CO. 104 W. ADAMS STRUT OHItAOO. ILL, A good article it alwaye imitated! Ba inn yen recalra tba FRESHMAN Variable Grid Leak and Micon Condenser Combined Price only $1.00 3 Points to Remember 1. It is hermetically sealed in a mould to prevent moisture from affecting the grid resistance. 2. It has an unbroken range from zero to 5 megohms, allowing proper adjustment for maximum efficiency of detector. 3. It contains a tested Micon Con- denser of .00025 M. F. At your dealers— otherwise send purchase price and you will be supplied without further charge. Manufactured by CHAS.FRESHMANCOMPANY,Inc. •7 Bookman St, Now York City Radio Silences the Chattering Barber • » » • n; . i r-l T if (C Wide. World Photos) liwrfon baa "gmm ua ana battsrl" inrtallad radio ae that than- cuatomara may Instead af harfcaj to listen to tba cbattar of aw a sat la bar/bar abapa In tba British, haar what ia sofas; on in tba aataWk world, tba "tonasrial artist." Hat* to a b. takttfe. WW. it Digitized by VjOO^ IC

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RADIO WORLD Agents LAJtOB MAMUVAOSOBM OaT ram mk um t* values. N* saplul «r iwqsdrad. WfM* far free maoihom shirt Miua _ S*T BrMdm New Tare. N. T. Do fon Like Clear Tone— Sharp and Distinct? If so try MARSH'S Vernier Variable Condenser AT LAST Made la Three Style*. Dial Knob tad Screw* Complete. Fully Guaranteed. t7-T>late © S5.M tt-Plate • W.75 11-Flate © 9*JtS Hall order* promptly filled. F. P. Marsh, 145 NicoU St NEW HAVEN, CONN. FOR CHRISTMAS $4 -The Little Wonder" CRYSTAL SET $2.58 UNMOUNTED Just the gift for jroar bar or «•* prepaid. Free catalaf aa raaeaat. GUARANTEED. Galen* and OA- TESTED CRYSTALS RadloelU...>'»c» Radi-O-PLata Paaal*. AD *Ua* cut to order. Holloway Electric Supply Co, lac ZSt Third Avenue New York City Made for Al Phones Ask Your Dealer THEY ARE GOOD Kk™iSS Slip out the metal dlM and slip In the MICA- PHONE. Beau It — Clearer, better tone, all nolaea eliminated. Write for circular. Discount* to dealers and Jobber*. M1CAPU0XE3 sell fast. TOBACCO HABIT BANISHED QUICK, SURE, LASTING RESULTS Redeemer banishes the habit com- pletely, almost before you know it. An absolutely scientific, thoroughly reliable treatment No matter how long the habit, or in what form used, you will have no craving for tobacco after you take this pleasant. Inexpensive treatment. This we positively guarantee. Your money returned without argument or question if not satisfied. Write for free explanatory booklet and proof of what Tobacco Redeemer haa done for men addicted to the tobacco habit. Send poet card or letter today. flewell Phannacal Co., Dept 971 , St. Louis, Mo, We Want Your Name on s parts) esrd. We would like ts set the aaeva of every RADIO WORLD reader, as ws expect to send out a special mssssfo to oar rssesra. It will interest you. Be tune to lend at yeur same as s peats! card and sddrsts It GIFT DEPT.. RADIO WORLD. 1493 Broadway. N. Y. Subsc' year, ' nio WORLD. $6.00 a -. $1.50 three months. RADIO WORLD TBLEPHONlj, BBTANT 4791 PUBLISHED EVERY WEDNESDAY (Dated SATURDAY or SAME WEEK I FROM PUBLICATION OKrlCS. _ 14S3 11 ROADWAY. NEW YORK. N. T. BY HENNE88Y RADIO PUBLICATIONS CORPORATION BOLAND BURKE. 11 RXKESSY, President and Editor M B. HENNE8HY. Vice- President FBED 8. CLARK, Bssrsury and Manager 14*1 BROADWAY, NEW YORK. N. Y. ASSOCIATE EDITORS Robert Masks; Robert U SUBSCRIPTION RATES i Fifteen seats s soinr. $6. 0» a year. IS.** ft* six month*. SI. 50 for three months. Add 11. 0* a year extra far postast to Cased* and foreign countries. Receipt by new subscribers of the first copy af RADIO WORLD mailed to them after sending la their order, Is automatic acknowledgment *f their proportions! rates. ADVERTISING RATESi One page: Ons Urns— 1150.00. Ball. Quarter, Third and Two- thirds proportionate rates. One Inch, one Urns — S3. 01. Par exits II S0.40. On four consecutive Issues. 16% discount- On thirteen consecutive Issues, 13% discount. Cover and preferred-position rates made on application. Terms: SO days Net. J* 10 days. CLASSIFIED ADVERTISEMENTS! Five cents per ward. Mini stum, I* words. Dis- count of 10% 00 4 consecutive Issues— 15% oa thirteen consecutive Issues. Cash with order. Entered as eecood-claes matter. March IS, ItSS. at the Post Office st New York, New York, under the set of March S. 181*. IMPORTANT NOTICE! While every possible ear* la taken to state correctly matter, of fact and opinion in technical snd general writings covering the radio Held, and ever; line printed la gone over with a scrupulous regard for the facts, the publisher rtlsfllalms any responsibility for statements regarding questions of patents, priority of claims, the proper working out of technical problems, or other mature that may be printed In good faith and on Information furnished by those aupiweed to be trustworthy. This statement la made In good faith and to ssva time and controversy In matters over which the publisher cannot possibly have oontrol. The Great Silent Audience By Rev. Claude J. Pernin, S.J. Loyola University, Chicago THE radio broadcaster who has had previous platform experience must change his whole mental outlook. He has been accustomed to "feel out" his audience. It may be cold, he must rouse it; I* may be critical, he must ingratiate himself; it may be turbulent, he must calm it! it may be sympathetic and "go along" with him from the first applause. Talking into a microphone is a good deal like making an impassioned appeal to a wooden Indian — the expended energy is all on one side. I imagine that as the broadcaster gradually builds up a new technique, he will draw powerfully on his imagination — and his success will be in proportion to his power to vis- ualize, just as the success of the speaker today lies largely in ability to "sense" his audience. He will stand in front of that steel transmitter in the solitude and tense silence of the KYW studio and a greater audience than ever gathered in the Athenian theatre of Dionysius or in the Roman Colosseum or on the hill of Tara will form in the prospect of his "mind's eye." He will visualize the dwellers in the city apartment, the street crowd that has drifted into the retailers shop, the farmer and his family gathered around the evening kerosene lamp in the living room, the lonely rancher on the western plain, the camping party with their outfit set up in the pine forests of Canada — did ever the human voice since man communicated his ideas to man have such an audience as this? PATENT I Tatar Radio letotve. Cast er Wrtte FREE ADVICE Vsarioesrept**** wfca -tat, $IM Jf envoy Back if aof «arsw>acss>ry osxjhND, ma IB FIFTH AV. II MSU -LITE p w —*\ t per oe, ra. A « per *«v ra. N 1/4" — M 1 paTHr*. E DBiLBMM: wnm far m ilh. L General 1 S aMsPBattw. ^sJw*"4aWsrwpfc* *Me #Va ViUtlO COUPLsERS Wo eJto meats* f of/tar ttylm* That List $2.50 up Jobbers — Dealers — Agents Write for Discounts Jewell Radio Sales Co. 90 West St New York City Phone Rector 10JS GITHENS TRUTONE RADIO HORN— LOUD SPEAKER First one to sell on ten day trial Money back Guarantee Retail Price $21.00 Includes Load Speaker Trutone hsa been pronounced the best an the market by experts. It has a elear. true lone Every radle fan should try Trutone snd compare It with others. If YOU don't find Trutons the beat, your mosey win be refunded. It Is sold on a ten-day trial SMsey-beck guarantee. If not carried by your dssler writs us Bisfri&utorg and Dealers, write I AUTO PARTS MFG. CO. 18IB Tromhly Ave. Detroit, Men. Any single copy of ginning with No. 1, IS cent* postpaid. Any $1.00. Or send $3.00 for 6 moa bars) or $6.00 for 1 year (52 a have your subscription start Radio World. 141 Radio World. be- ef for Ik. (26 i • )« Digitized by Google

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RADIO WORLD 25 INCREASE YOUR CRYSTAL RANGE BY UMNO A TT t'LTKA-aCMMTIVB CONTACT IN VOI K CRYSTAL DRTRCTOR I. II Meatee a leaettrve aaal Mnllr. 1. Br tail WMla and eeae to leader. S. Wlteetaed. kwr hdtt attkeat iarrlee tat. Mm. alt* UatrertJeee, IMD'ln nati. "FT" CRYSTAL. CONTACT COMPANY Ra» 1*41 BOSTON I. RAM. Thr Nlftleet Short Wave Tuner on the Market Only M-M A TP on I lb. Sand (or pamphlet. L. W. GOODMAN DREXEL HILL, PA. Meier . Mediae. N. ».. write.: OelliMed. Received Sihrnrct.idv clr.rlv en one lube fl:it tint I tMrd'h. GOODMAN. BmM "be,. V.ed triable .Vi ■voficy ay buy in v nvnthi ajo. SURPRISED? ■ ■ Everyone 1 1 Becauee WE REPAIR " Broken and Burned-Out m VACUUM a TUBES ' Year II aa Arm not. wad dlrvct !• HARVARD RADIO LABORATORIES Boeton 9. Maea, Tebee returned Pereel Pert CO D. FRS ALL MOLDED UNIVERSAL COMBINATIONS • I mi. la 1 F. It S. Molded Varturortara R F. K 8. Mnldrd Varlaroupleee . . F. K. 8. Mold.-d Hank Wind I ace Bank Wlndlnca are Intrrchanceable direct mountlni on either Vartometar Varlocoupler. M.SO •-r» i*Ti c Set Includee two Federal Trnneformere Condenaar. tero-moldrd eerlomelrre. molded varlocoupler. three V T eockete. fllament rheoatata dlala Head 'Em binding poate, aerltch polnto; In attrao- tlea cabinet end drilled panel: complete, ready to hook up. A fill Radio ror F. R. S. Radio Corporation 4aa-D i n-t Kan 8t. D*treet. Mieh. $40 — Subscribe direct or through your $6.00 a year, $3.00 six months, $1.50 three months. Radio World, 1493 Broadway, N. Y. C Broadcast Bill's Radiolays By William E. Douglass OUR neighbor's son— I call him "Bub" — is only five years old, but sharp as tacks an' curious too, 'bout some things he's been told. Fer instance, he's had doubts of late regardin' Santa Claus, an' to hie vrav of figgerin' our etoriea have some flaws. "He can't come down the chimney," Bub sez, "fer it's heaps too small; so if there is a Santa Claus he comes in the door, that's all." "How can Santa visit all the children everywhere?" I told him that wuz easy 'cause he travels through the air. "I wish that I could talk to him," Bub sez to me one night; an' then I sez, "I reckon we kin fix that up all right. "You know he lives away up North but maybe I kin get old Santa Claus to talk to you through this here wireless set." I told Bub to come over to our house on Saturday. "If we kin make connections we'll hear what he has "I put tba ear-muff e on the lad and then 1 made a ehow of luaeia' with tba eet." to say." I'd noticed in the papers where they said that he would speak to all the children everywhere by radio this week. Next day when Bub came over he sed he would like to hear what Santa (if there wuz one) had laid out fer him this year. I put the earmuffs on the lad an' then I made a show of fussin* with the set a bit to make it seem as though I really had "tuned in" that place that nobody kin see where Santa makes all his toys — The North Pole Factory. When every thing wuz ready an' Bub lis'nin' by the set. Saint Nick begun by askin' him what all he'd like to get. But 'fore young Dub could answer he sed "how'd you like to have a sled or would you rather have me bring a tcctri-: train instead? To every boy who believes in me an' tries to mind his dad, I'll bring a lot of presents; but fer any boy that's bad. who doesn't help to do the chores an' carry in the wood. I'll take his share of toys to the ones that have been good." When Santa Claus quit talkin' Buz wuz quiet as a mouse. This radio's a handy thing to have around the house. Copyright. 1022, Wctincbouae Elactrlr A Menu- facturina Company Government List of Amateurs Ready AMATEUR Radio Stations of the United States. Edition of June 30. 1922." is ready for distribution, according to the Department of Commerce. Ap- plications should he made to the Super- intendent of Documents. Government Printing Office. Washington. D. C. The price is 25 cents. The publication con- tains 300 pages and records 15.504 amateurs licensed up to June 31. 1922. « SPECIAL OFFER Far a I eelled tiaee ealy. RA-10..SSS Grata CR-S ST* DA-S... SS Grebe RORK «S ►Meat F.O.S. Sad Baaa. M. J. A. V. GREGORY Street Beat Baak. N. J. ^ F°n«V23,piat Flnaat 43 Plata Caeh a $1.00 $3.52 r.lh Order RADIO ENGINE Filth Ave. and 2Sll Ti! HOMCHARGER AUTO or RADIO H A T T E R T Mr a N let at. Pre*. I lit* Seed I., rati SelMte OKALIRS— WRITS NOW Tee villoma llr Kleetrirad nr. Devlraa Ca. "B Weel Tetrd St.. Ota.. 0. 531 SO DEARBORN ST. CHICAGO SAVE MONEY ON HIGH GRADE Variable Condensers Direct from Manafartarar* Taka tha mldtllfmin'i profit and call- ing coata for yourari. \\ • aa>li 700 di- rect Th»if at t rtmtlr a ecu rata Inatrv- inania mad* by air>*>rlt>nc.t»d candanaaar paopl* arr mlnua lha dacorailv* frill* lhat add 10 coal. Prlca rrducad (a rock bottom without a* critic In a; qualltr I" Ilia lata. ftat.afaciloD or your moft#y bark Writ a today for very Intareatlna; air- niter. Ha cWas we sWaai Or* — la- TODAY • • t» aa*s«r bm Iliac aajt daWRaaT 1b * day aa* >*F«> ■salver. I aad ifae>l isj rsaW aaa- MANTTFACTITtERS' RADIO ASSOCIATION St) P.a.t Kinney St. Newark. „. e

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26 RADIO WORLD Complete Your Radio Library Technical Articles Published in Radio World to Date of Inductance Colls, by Fred. C APRIL. 1. A 500-Mile Radiophone Employing a 5-Watt Tube, by Prank A. HabaeL "Tell Me, Pleess, How WU1 Thl* Set Re- ceive?" bjr B. L. Bragdoa. Snort Cuts In Reoelrer-Clreutt Design, by O. C. Roo*. Making a Bhort-Wavs Regenerator, by Prod. Chaa. Bhlert. APRIL & Do Too Know Tour Receiving Bqulnmoat. by jamee D. Gordon* Why a Crystal Is Called a Rectifier, by Wal- ler Bm mett- le Radlotelephoay OependableT by O. C. Rooa. Mounting Crystal* In Tour Detector, by B. L. Bragdon. Storage Batteries tor Radio, by Prod. Oka*. Bhlert. APRIL IS. First Principles of Bleotrietty as AppUad te Radio, by John P. Miles. Tour Storage Battery, by B. L. Bragdoa. What Makes Radio Possible, by Rdward LU- wood. O round Connection as Vital as Antenna, by Fred- Chaa, Bhlert. APRIL 28. Valuable Pointers oa Aerial Construction, by Edward Unwood. What Is Meant by Tuning, by B. L Bragdoa. Radio-Frequency Amplification and Regene- ration, by Frank Armstrong. Honey-Comb Colls and Condensers, by Bd- ward Lin wood. Charging the Storage Battery, by B. L Bragdon. How to Construct the Varlocouptor, by Fred- erick J. Rumford. MAT 6. The Advantages of Radio Frequency, by Harold a Potter. How to Construct, Protect and Operate a Storage Battery, by George W. May. The Beginner's Catechism, by Bdward Lin- It Meant by It, by Prod. from a Simple Receiver, by Tun lag ■hit and What left. New Frequency Amplifier -Brings Waves la Strong, by O. W. May. MAT IS. My Practical V. T. Detector aad Two Stage. Amplifier, by Frederick J. Rumford. The Principles of Radiotelegraph*, by Wal- ter J. Howell. The Reason for the Loop Aerial, by Qoorgs W. May. Tuning and What Is Msaat By It, by B. L. Bragden. . The B Beginner's Catechism, by Bdward Un- MAT SO. The Design of an Amateur Receiving Set, by a White. The B Battery and the Plat* Currant, by Qsarg* W. May. Radio Terms at a Glance, by Fred. Bhlert. The Beginner's Catechism, by MAT ST. The Beginner's Catechism, by Fire Undewritars' Rules, by Fred. Chaa. Bdward Lin- He* to Make Tour Own Condenser, by George W. May. Tuning aa Applied to Telegraphy, by Walter t. Howell. Why the Condenser Doesn't Condense, by B. L Bragdon. Making Signals Louder with Two-Stag* Am- plifier, by George W. May. JUNE 8. The Coat of a Single-Circuit Receiver, by Howell W. Miller. The Beginner's Catechism, by Bdward Lin- How to Compute and Build a Fixed Conden- ser, by B. L, Bragdon. Design for an Amateur's Receiving Set, by a White. Simple Method of Recharging a Storage Bat- tery, by John Grayson. JTTNB 10. Radio Receiver tor Short Waves, by George W. May. How to Filter Atmospheric Conditions, by G. Whits. The Messenger Boys of Broadcasting, by B. L Bragdon. Are Tou a Member of the N. O. D. C.t by B. L. Bragdon. The Beginner's Catechism, by Bdward Un- wood. How to Conitruot One- and Two-Slid* Tuning Colls, by George W. May. JTTNB 17. The Vseunm Bulb's Start In Life, by C. White. How to Select the Rlgbt Bet, by ID. L. Brag- don. The Beginner's Catechism, by Bdward Lln- wood. Test Baton. Short Waves Stanley Bryant JTTNB 24. How to Make Tour Radio Cabinets, by W. S. Standi ford. How the Crystal Detector to Used to the Beat Advantage, by C. J. Williams. How to Construct a Long-Wave tire Reoetver, by George W. May. Tested Invention of Major Armstroai lies Set 100,000 Time*, by John Kent. Repairing Cracks la Hard-Rubber Battery J aim, by W. 8. Standi tord. The Beginner's Catechism, by JTJLT 1. Novel Unit-Detector and Amplifier, by erlek J. Rumford. Why Tou Must Use a Condenser, by C Williams. How Wave Lengths Travel, by Prod. Bhlert. Radio World's Revised Dictionary, by Chaa. Bhlert. The Beginner's Catechism, by Bdward Un- wood. Use of the Vacuum Tube Detector, by George W. May. JULT 8. Radio's Plsoe In the Phenomena of Nature, by B. L Bragdon. , The Function of the Loose Coupler, by Charles H. Plata. Armstrong's Superregenerative Amplifier Fully Explained, by John Kent. Operating a Transatlantic Station, Chaa. Bhlert. The Beginner's Catechism, by Fred, y Bdward Lln- Reductng Stray* and Static, by Fred. Chaa. Bhlert. JTJLT 16. Assembling a Detector and Two- Stage Ampli- fier, by H. 8. Stanford. Combined Radio and Audio Prequene> Ampli- fication, by C. White. The Beginner's Catechism, by Bdward Lin- wood. Locating Tour Aerial, by Harold Day. Facta for Beginner*, by Fred. Chaa. Bhlert. JULT 22. When Tour "Movies" Come by Radio, by Been- ley Bryant. Underlying Principles of the Vacuum Tube, by George W. May. Practical V-T Detector Panel, by Frederiek J. Rumford. Revised Radio Dictionary, by Fred Okas. Bhlert. The Beginner's Catechism, by Bdward Llawosd. Importaao* of Aerial* to Badlstlon, by a White. JULT SB. The Vacuum Tube as a Transmitter, by Charles H. Plata. My 30> Kilowatt Tub* aad It* Uses, by Irvtag Langmulr. Importance of the Capacity Switch, by & L B Tne^Truth about Lamp- Socket Aerials, by Harold R. Hart. _ AUGUST 6. How to Construct aad Operate the Amotion* Superregenerative Circuit, by Jean KeaL Using Radio Frequency to Bxtead Range, by George W. May. Things Every Radio Fan Must Knew, by E. B. Hawtoy. Revised Radio Dictionary, by Bhlert AUGUST IS. The Work of the Audio-frequency by George W. May. Practical Measurements of Capacity aad In- ductance, by W. A. Dickson. Experimenting with Armstrong Circuit Pro- duces Unusual Hook-up, by Dr. 0. B. Kelly. How to Secure Perfect Regeneration, by Fred. Cbas. Eblert AUGUST 10 How to Build a Portable Field Busser, by Do Witt H. Thompson. Using Two Tubes for Receiving, by C. White. The Storage Buttery s* an Important Factor In Radio Reception, by Donald Van Wyek. The Use of Capacity In a Circuit, by George W. May. The Beginner'* Catechism, by Bdward Lis wood. AUGUST SS How to Build a Spider- Web Receiver, by Frederiek J. Rumford. My Detector and One-Step Amplifier, by Fred. Chaa. Eblert The Beginner's Catechism, by Edward Lin- wood. Hints for Fans, by C. F. Rye. SEPTEMBER 2 Generating C-W for Transmission, by O. White. Wonders of Radio-Frequency Amplification, by H. S. Potter. How to Connect the Electrlc-Llght Socket Aerial, by John Kent Practical Clroulto for Regenerating Loud Sig- nal*, by 0. 8. Kelly. SEPTEMBER 0 Radio Idaaa for the Amateur to Teat Oat by Carl Hasson. How to Make a Practical Wave-Motor, by Frederick J. Rumford. How to make a Honey-Comb Coll with a Twe- Stage Amplifier, by Fred. Chaa, Bhlert Perfect Short- Wave Radio- Frequency Ampli- fication, by George W. May. SEPTEMBER 16. How to Make a Two-Tub* Buperregenerator, by Frederick J. Rumford. Method* of Amplifying Radio Signals, by B. Bradbury. Voice Distortion In Vacuum-Tube Receivers, by W. A. Dickson. Charging a Battery — from a French Radiotot's Point of View, by Marias Tbouval*. Working Diagram* tor Beginners. SKl'TBMBEB 28, 1022 New V T Hook-up Worth Testing Out, by P. F. Metsler. New Method for Lighting Filaments, by C White. Why the Radio Compass Is the Fighting Element of Science, by Ortherua Gordon. Complete Table of Symbols Used in Radio Reception, by Fred. Cbas. Ehlert. The Radio Primer, by Edward Linwood. Complete Method for Building an Electron- Tube Detector Unit, by Bxperta of the United States Bureau of Standards. SEPTEMBER SO, 1022 Increasing the Wave Length* of a Receiv- ing Set, by George W. May. The Importance of the variometer to a Re- ceiving Set. by Donald Van Wyck, Successful Stunt* of an Amateur Radlolat, by C. F. Rye. Employing Jacks with a Two-Stage Ampli- fying Receiver, by Fred. Cbas. Bhlert. OCTOBER 7. Superheterodyne Receiver aa Applied to the Armstrong Superregenerative Circuit, by Charles R. Leuts. Constructing s Radio-Frequency Regenerator, by C White. Why the Open Antenna Is Best for the Rathe Listener, by C D. Wagoner. Broadcasting Stations of United States sad Canada. The Radio Primer for the Beginner, by Lyaa Brooks. OCTOBER 14. Nest Home-Made Tube Socket, by Gordon S. Arthur. Vessels Now Guided Through Fog by New System of Radiotelegraphy, by Otherus Gordon. What Makes the Receiver Work, by Donald Van Dyck. Using the Vsriocoupler in s Short-Wave Re- ceiver, by George W. May. Regenerative V-T Receiver for Short Waves, by Fred. Chaa. Ehlert. OCTOBER ZL Important Improvements in Radio Receivers/ by C. White. ' Be Sure of Your Ground Connection, by Fred. Chaa. Ehlert How Radio Was Installed in Our Home, by Hattie Briggs Hartman. One-Tube Regenerator Hook-up for Loud Stgs, by Harold Day. Every Radio Set Hae a Reliable Range, by John Kent The Theory of Radio Communication, by Horace Beers. OCTOBER 28. A simple Super-regenerative Receiver, by Har- old S. Potter. Vacuum Type of Arrester Ssfe, by Fred. Cbas. Ehlert. .How to Make Your Aerial Function, by Horace Beers. How to Avoid Interference When a 369 Meter and a 400 Meter Station Are Operating Simul- taneously, by C W. Horn. NOVEMBER 4 Receiver for Amplifying Weak Signals, by Hor- ace Beers. How to Learn the Code, by Ortherus Gordon. Detectors— and How They Work, by Donald Van Wyck. One of the Most Delicate Parts of a Receiver, by George W. May. Wave Meter for Amateur Operators, by United States Bureau of Stsndards Experts. NOVEMBER 11 How to Build s 100-Meter Concert Receiving get, by Frederick T. Rumford. WWe Field for Experimenting srith Aerials, by Donald Van Wyck. Single-Tube Superregenerative Receiver, by C White. Utilizing Ford Spark-Coils for Audio-Frequency Transformers, by Ortherus Gordon. Why It Is Necessary to Tune In, by Arthur G. Shirt. Any single copy of Radio World, bo- ginning with No. 1, mailed oat receipt of 15 cents postpaid. Any sorest issues far $1.00. The full 32 numbers seat for $3.75. Or send $6.00 for 1 year (52 number*) and hare yonr subscription start from No. 1. Radio World, 1493 Broadway, Now York: Digitized by Google

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RADIO WORLD 27 Include These Items In YourXmas Gifts! THE giver of Pruden Reliable Radio specialties is remembered a long time. Useful, practical Christmas gifts that know no equal to the radio fan. The "Pruden" stamp on standard radio parts and accessories, denotes an unexcelled quality and long-time satisfaction. Money back if not more than pleased. Just a few Xmas suggestions shown here. Write for complete list— free on request. This is a Radio Xmas! Dealers, write today for our interesting proposition. FREDERICK H. PRUDEN INC. 993 Bergen Ave. jHKgHjenejr City, N. J. la bars tooj^ta wlrlnc KHa- ""»$2.00 Radio Detector Ifca only And radio Matter nqatriac aa adjustment. Uasd In plana af ar/stal at Taaunm tuba datartar. Ottos until ant ouailty af round without dtatartlaa. saatsc/ ar tube nalaaa. Dataats tstacnaa aUadk at ami ibouaaod srilaa. Dataata braud- aastad audi am slaarly ttaaa ruaoua tone toaator. and raqulraa na uapllfiaa- Uon where tba Inaooeuut etmal una saaTl- elant atranrth to actuate tba 1 1 all II 1 1 Idaal for oat la itjsnoaratlee diets ■), Bandaaow. oubetanUal. aulubU for as- stably In tba nonet ndla aoalaaneut. Ouarantaad ualnat Imparfaatloa «« Kit ar faulty operation. Uat each.. Molded Tarimutar (Laaa Dial) la mada af Baatana MoU- Dlsleotrla, harlns aztrana will not warp andar Tola feature la not •BS^ .^$5^5 Bestone Paten tlometer Thli Potentiometer with 1-lneb Moldad Dial. Na. T64. MO Ofama. }\J5Q Bestone Rheoatat — t-lach Mad 81mllar ronrtructioo to racular Bl la furalahad with i-lnob Moldad I Dial far front PanaL No. Tt4. " ir Bhaaetat, 83** *^WZ&Wt&tof>&3t&&Wti RADIO UP TO A STANDARD BUT DOWN TO A PRICE FOR 30 DATS Far thaw price* mention RADIO WORLD. All roods new. In original pactoNres. IIM.SO ante 0. R. «. 1(0 to 1(00 bm< HI. 80 Wetflesbseat R. O. II2.M Da Faraat at " 26.it " • - - ■ J. t • "• tiL" tartliao.oi •III (4.00 12.60 618.(0 TueXa Dataatar Sat 3I.SI Da Faraat Datartar Sat , 35.60 Da Faraat 2-Staae AaplMar 125.01 Saaaral Elettrial-i 126.00 21.(0 21.(0 Staoa AnnllSar. •(.•( V. 200 O. V. 201 Haw V. T. I PHONES Baldwin Type C 110.00 Baldwin, ungle S.OO Holier. Cabot 5.50 Murdoek 3000 ohm 4.90 Murdoek 3000 ohm. tlngla. 2.00 Murdack 2000 ohm 3.00 Mareoak 2000 ohm. tlngla. 1.30 Brsssea 6.00 Fadaral 2200 ohm 6.50 :::::: 1% French Bruaett. 4000 ohm. 7.76 VARIABLE CONDENSERS 23 Plate Vernier 43 Plata Vernier t Balanced Vernier. . . «S Balanced Vernier .0015 Balaaeed DeFerert. .0003 Balanced DeFore.t .001 Balaneed DeForert. 23 Plata Moulded 23 Plate VARIOCOUPLERS Baldwin All Kange All Wave Atwater- Kent Emca Tuoca $5.25 . 9.75 0.00 4.80 5.20 6.00 4.50 4.75 1.25 1.00 •4.50 6.00 7.60 (.40 4.73 3.50 (6. 6. 4. (. Sellable merchandise first, then price. We will refund, pnrrhaoed from as which Is not up to standard and i TUBES (4.00 I Navy V. T. 6.00 W. D. II. (.60 I U. V. 2(2 . BATTERY OHAR8ER6 WaatlMkaans 2 Amp (16.1 weaUsoMUM (Una) ( Ans.22.1 RHEOSTATS Radla Car* 2.' Basilar 2 $7.5( (.(• 7.SS Oetlar Haatasr... I POTENTIOMETERS Radla Oar* (I. Parana I Smsalta |, I LOUD SPEAKERS ..1(1. .. 6. .. If. .. 17. ..120 . 17 Elaavia Baldwin Coarasheaa. Pstks Ea VARIOMETERS Atwatar-kaat". TRANSFORMERS U. V. 712 (5.00 AasM 3.73 A two tar- Kent 5.00 Fadaral 5.25 Pangea 4.00 Mayan Oall :.. (.(( Maria 8.00 Tbardarasa 2.76 RADIO FREQUENCY TRANSFORMERS U. V. 1716 (7.60 U. V. 1714 5.60 Radla Santas 4.75 Balawls 2.25 Arena 4.(0 . _ DIALS 4-ls. Tslt (1.00 4- ls. Paths .75 5- la. Radios 5( (•la. Pstks (0 SOCKETS (0.(0 „ (0 DaFarast g« W. D. II oo JACKS sad PLUSS , —J ((.76 Sua Oris to Firth, alalia 55 Flrtji, doable .so any time, for Badlo material represented. No Checks. No C. O. D. Add Parcel Post. Reference: Badlo World. 577 MYRTLE AVENUE Phone Prospect 2952-8168 BROOKLYN, N. Y. Radio World 1 Year (52 Numbers), $6.00 "B" Batteries That Last far Fits Yssn RADIO F.OIIIPMENT MFC CO 16(1 JKRSMK AVE. NEW YORK. N. V. Look Spider Web Inductance and Discs that give the wonderful re- sults as described in Radio Age. Inductance wound complete. .$ZM Disc Only M Plsgism for connections free with erdsr. We are manufacturers of Stor- age Batteries for Radio A and B circuit. WRITE FOR PRICES International Battery Co. 112 Lotas Street, N. W. Grand Rapids, Mich. dOQglc Uiyili^ed by VjQQgl

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28 RADIO WORLD RADIO PANELS Hlfk dlalattrla rwMuM. S"*t4" »1.00 S"rf4" L» l*"xt4" 1.7« Mssufaatvran' ip*«ill alzaa •alltlta*. Ataats waatsd. PAGESON COMPANY Bai ««. Marasaata Statlaa. St Unit. Ma. Radio Makes Flying Safer Bureau of Standards Developing New Type of Altimeter to Be Used in Conjunction With Radio A MODERN airplane is fairly safe so long as the pilot can see the ground; but with the ground hidden by mist it is in a very dangerous predic- NatMas jfctTOta. REAL CABINET LOUD SPEAKER NOT* tUST THE USUAL HORN ENCLOSED IN A CABINET BeadiM-CoMad-TONE COMPARABLE ONLY TO THE FINEST CABINET PHONOGRAPHS snaraataa tnalr Hm SPIROLA DUPLEX— Isr ana TOMC CHAMBER FOR DB> Osk (00) sr ■isijssy (DM) - SIMPLEX — far u SEPARATE EACH PHONE. allelsatlsf IsMrlSfsaa Sstls Mask Sal*, slaiaNa lltlsta. (f " $3.85 SPIROLA •silk, nrsssaf tkrwt uS wim. inwM mwi mmm tttlSSI ................ $4.SS •Ilk BsMwis ar sUar nil. Blast (OB), ask (80) 4 utolii) ors or drawers in the way and enough room to sit up comfortably and operate. Size of top 22x36 in. Height 31 in. Made of Birch in Walnut or Mahogany rubbed finish at $18.00. Or of solid Oak in Golden or Silver Gray finish at 9.00 each. Shipped direct from the factory upon receipt of price. Specify freight or express. Proposition I i dealers. MADE BY WM. THIES & SON, Huntingburgr, Ind. Manufacturers of Telephone Cabinets since 1902. YOUR NEWSDEALER wUI dstivsr RADIO WORLD to your bow. Ia srdsr to bs surs of r*ttias RADIO WORLD ragoiarlj, and of not missing ■ stasia iaaua, we sufgast that yon sHhar subscribe direct sr through rear am- dsslsr at M.SS s yssr (S2 issuss), S3 J* aix months, and SLM thrss months. Or Instruct year i to dalivar RADIO WORLD raguUrly to your noma inch wash. DsaJars will taha staadJa make daUveriaa of papsr whenavsr rsquastsd. Radio World, Ion Broadway, Naw York. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Please send me RADIO WORLD for plrase Hmd enclosed $ . . ■UBSCRIPTTON RATES: Mnaie Copy I .11 Thras Months 1.50 Sis Months 3.0D Out Year (52 Iaauea) 4.00 Add 11.03 a v Ror»igr and Can ad 1493 Broadway, New York City months, for which ament, the Department of Commerce points out in relation to a new airplane altimeter being developed by the Bureau of Standards. It cannot stay up in the air indefinitely, and when it tries to land it is quite likely to come in sight of the ground so quickly that there is no time to turn. Moreover, the pilot, out of sight of earth, has no way of telling where he is. He knows his own speed with relation to the air, but cannot tell the direction or velocity of the wind which may be an appreciable fraction of his own speed. Recent inventions have done much to eliminate this hazard. Pilots of the United States Mail Service now make regular trips in all sorts of weather and land safely at their destinations. Chief of these is the radio compass. With this device it is possible for the pilot to tell the direction of any station sending signals and to steer towards it He has thus eliminated the danger of getting lost; and so long as there is a space of clear air under the clouds, he can get down safely. However, when the earth is blanketed in fog the pilot must know not only his direction but also his altitude relative to the landing field. For these he must rely on his altimeter. Now, an altimeter is nothing more than an aneroid barometer with a scale in altitudes. Like any other barometer, it changes not only with the altitude but with the weather as well, and it gets these elements inextricably mixed. A _ change in weather may change its readings by an amount corresponding to a hundred feet or more in altitude. This difficulty is largely eliminated in airplanes equipped with radio by a new altimeter being developed at the Bureau of Standards. This instrument has the usual fixed scale, and it also has a mov- able scale, the zero of which can be set at any point of the fixed scale. In ap- proaching a landing field, the pilot gets, by radio the barometer reading at the field and sets the zero on his movable scale to that reading on the fixed scale. His altimeter will then tell him accurately how high he is above the landing field and will enable him to get down safely even in a fairly thick fog. When airplanes become more numer- ous, it will not even be necessary for the pilot to have a radio-sendmg station on board in order to take advantage of these inventions. The radio compass itself is merely a special form of receiv- ing set but little heavier than an amateur set; and this can be used for getting the barometer reading which could be broad- cast at regular intervals. To the Man with an Idea I offer a comprehensive, experi- enced, efficient aervice for hi a prompt, lepra.) protection, and tbe development of hit proposition Send sketch or model and descrip- tion, for advice at to coat, search through prior United States patents, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable me to accurately advise clients as to probable patentability before they go to any expense. Rwklet nf raluBbVa Information, and f«nn far properly ,a*rlf»ilnB your Idea, fre» an request. Write today. RICHARD B.OWEN, Patent Iwya, 32 0w,n Building. Wmhlaatsa 0 C JJ7S-P Waaiwartti Bid,.. Naar Vara Cltr Digitized by Google

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CHRISTMAS OFFER SEND $3.60 Ck «r Mo~y Or*r O-hr. "^jJ-T? SYKES MFG. COMPANY U SPRINGFIELD AVENUE NEWARK, N. J. Xmas Specials Matter Baldwin headset! Acme Tranetbrmere *"* General Radio Tranaformeri *»» Hordock phonea. 3,000 ohme... *•*• 4J.P1.tc condeneere, food quality *■» 23-Plate coodenaera, good quality 1*» Zeta R. F. transformers *•* (High point 360) « Plate .eroier coodenaera. with knoo and dial *"* 23-PUte vernier condenaert. with knob and dial *™ Genuine Bakelite aocketa .... Federal Jr. Set with Federal Aerlein Jr. Set with Braadee I Acmeetata * SPECIAL OFFER With every fir of Federal kaadatU at t&M w. wUl giva FREE a geo4 quality rhaoeUt He etesk. ar C. 0. O. Me ■alt wear ssry. Manhandle* eMeaai S. A. Marchfelds Radio Shop atl Watt atlta Street. New York CHy RADIO WORLD And They All Work! Radio World Reader Triaa Out Every Hook-Up Pabliahed im Tkeae Pagaa EDITOR, Radio World:— I have experi- mented with the hook-up published in Radio World No. 35, dated November 25. under the heading. "DX Hook-ups for the Novice." and have had wonderful success with it, bringing in stations that I could not get with a three-circuit regenerative set. I had some trouble at first to make it oscil- late; but, by mistake, I put a 23-plate con- denser in the antennae circuit and was sur- prised how easily it then oscillated over the entire range of the variometer. I always try out every hook-up published in Radio World, as I have found, from experience, that they are all hook-ups that work. There- fore, it is more fun to know that you are going to get results from them. Yours for a DX Christmas.— William Buxton, Laredo, Texas. P. S.— Maybe this will help oat some of the fellows that have had the same trouble as I did with the above circuit— W. B. An Inexpensive Panel WHEN a beginner is planning a set, frequently he figures up and de- cides to iXMtpone the task another week ; or else he asks dad if he won't give "a couple more." , One of the ways to save some money when building a set is not to nse a bakelite panel If it is not necessary that the panel be black and shiny, use a piece of good dry hardwood which has been soaked in boiling paraffin. Place the wood in the paraffin until the little bubbles cease. Take it out and let it drip for a while, then immerse it again. If no more bubbles appear, the paraffin has soaked into the wood and it may be used without fear of either warping or becoming moisture soaked. Ideal Radio Night MOONLIGHT has no appreciable effect upon radio transmission or reception in the northern section of the country, says "The Times." New York, but operators who have sailed through the tropics say that the moon has a tendency to weaken radio signals in the southern climes. The effect is more noticeable m connection with spark signals. Fog ; gen- erally weakens the strength of radio in that the air and objects enveloped by the fog are damp. The dampness makes them better conductors of electricity and causes them to absorb the radio impulses. The ideal night for established long-dis- tance radio records is the one having the cold, clear atmosphere of winter, just after a storm with its low hanging; clouds has cleared the air. RADIPHONO ADAPTER Il.ro U u ofTlrl««it m- InomlroJ ear la T« tor f»"»i wi ewaaae Industrial Snira Engineering Co. •71 Breia Sb**t. Mean*. U. 1. PHmr, Market 9023 J PRICES SMASHED! Rond mix! for Wkll Ust « wow JSgi lot euapl. awlac rood. pr«^W BdlkW wllhlo 14 ham attar rwjloi at order. . °Ta,_r* unabU fw roosts w eubasje. Tea aUastf eaa * DU"^° IBS ttWSUE™ aay.a/jj » . •••• t Fllaaiat jRaw»tat. O ••!! !U^tPa^AIS g tn 1.7* M At M lll.Ss ft* ?««-S!5Jl5-» m :. OkaetraafctSM +m S.SS W»swnillso«r«. Itt» ■ _• ••*» Detawar Teas*. Caaalaaaaav New.. S.t» Radfa Parte Maaafaetariac Company II PARK PLACI DtTBOIT. MICWIaAW lll.tl SI.M S.M) VARI0C0UPLERS 65c WH* away mm aa mm oHe a ewa-as tar aalao tmTSVmmfS nZSm fraa 1H • See aawa. SOMETHING NEW 4-WAY TaXEPHONB PWJO Takes the flaoaat 1 rtap and a JJaak flJO Att aclee irrtceeta »ma~U>***~ read BAJ)10 WOULD mvmrm maamt We w«»« picture, ol reccWIot aeta with description, oi how too OTercame mat tifficoltr. or oi «o» additional part or amit that you haee added to obtain briter rcult.. Theae are the thine, that, proo- ably. the other Irltew it look.oi tar. Sead in rour mform.iion; picmrc or _ »««■ e»er joa hare done to improve the art Aaklraas 1H tcTiJ: !^t^ jr^T ^Tm^la. to radi. amat^ Ur- be eecrat brother dotea anything, don't keep th. bat tea it to year tboaaaada oi (ana. , . Bead hi a photorraph of yoar aet wMfc or^Tthoat a^ccoaipaayint L aauorraeat Stale wither yoa •»« in the pictara yoaraeH. or not. o.t any eapeeae wh.t*oe»er to yoa we wiO atake aa eawraTinc »»d paoaaa tt. Be .are to write your aaate ana aaereee pUmly on photofraph. Sand in your pictare at once, ar H »wa have not m»<ie a aet or done aaytBiag elae io making radio material, tea rae boy neat door all about thia aSer. Tackaiaal aUBtoT RADIO WORLD. 1493 Brotulway. New York Clto, N. Y.

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30 RADIO WORLD DO YOU WANT TO BUT, SELL OR EXCHANGE RADIO OR OTHER GOODS T DEPARTMENT AT fa A WORD TRY THIS RADIO WORLD S QUICK-ACTION CLASSIFIED ADS This department is intended for everybody who wants quick action on short announcements covering the buying, setUnt, ' exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that it pays to read these colutsi every week. Advertisers will get a ten-day service here — that is, copy received for this department will appear in RADIO WORLD •a the news-stands ten days after copy reaches us. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. per word (minimum of 10 wordv including addtess), 10% discount for 4 consecutive insertions, 15% for 13 consecutive insertions (3 months). Changes will be mid* k standing classified ads. if copy is received at this office ten days before publication. RADIO WORLD CO, 1493 Broadwiy, M, Y. C (Phone, Bryant 4796). PATENTS— Electrical cue* • apodal ty. Pre- war charges. B. P. FUnburnc, Registered Patent Lawyer, &S Mofita BU«., Washraejtoo, D. C AUDIO FREQUENCY eBminates howling. Eatirelv satisfactory oa three stages. Price $S.ot poetpaid anywhere ia U. S. RADIO SALES CO., Baa 1144. Bet" " SILVER MIRRORS— PLATINQ OUTFITS FUR- NISHED—Stop daily grind. Plans free. Estab- ■sbed KM. CLARENCE SPRINKLE, Dept. ». Ifariocs, Indiana. EXCHANGE JOLLY. D4TERE3TTNS LET- IWtS through our crab. Stamp appreciated. Batty Lee, lac, 43S4 Broadway. New York City. DIALS, 3-inch, geauine hard rubber, raised or depressed scale, white or gilt lettering. Drilled far 14 and % inch (bafts. 60c each. J for 11.50, poetpaid. No •tamps. RADIO SALES CO., Boa 1144, Bethlehem, Pa. NEWS AND OOSSIP OF THE STAOE-Sand eta, far specimen copy of NEW YORK STAR, the great illustrated theatrical year, $2.00 abx months, $1.00 three mon York Star Co., 1493 Broadway, N. Y. tna. New A VALUABLE RADIO LIBRARY— The special articles in back numbers of RADIO WORLD area April 1 to date, make an iaralnable library •J information and ratal ansa far everybody la- sted ia radio. Single copies 15c each. Any . numbers for $1.00. The entire thirty-seven asm bar • to date for $4.25. Our issue of Oct It eon tains a list of articles published up to that data. Sent on receipt of lie. RADIO WORLD, MM Broadway, New York. RADIO FANS: Have you read el the won- derful new all- wave Radio Frequency Ampllnor invented by Doctor Miller of the Naval Radio Research Laboratory, Bureau of Standards, Wash- ington, D. C.F We manufacture this devise under license. May be added to your present set, giving wonderful results on distant stations, er may be made up into loop receiver sets with extreme range and beautifully clear reception, far home or. automobile use. Besides being the bast amplifier on the market, the Miller covers all waves at equal efficiency. Price, S6.S0 per mslt. Details free. Coast Radio, Inc., El Moats, Las Angeles, Calif. PATENTS Protect your las —Men teeny. Write far 021 Illustrated Book Free. Radio, Electrical, Chemi- cal and Mechanical experts. Over 30 years' ex- (Radio 3 ARB), 110- perience. A M Wilson. Inc. (Radio 3 ARB). ltVlrse U Victor Bnflding, Waahmgtoa, D. C (Succeei ^ »• to business established ISM by A M. Wuson.) 9a per sensitive tested Crystal No busier test necessary. If aot satisfactory, return crystal and money will be refunded with mailing charges. Mounted, 50c.; unmounted. 45c Special Prices to dealers. Wm. Hafner, 72* New St., Camden, New Jersey. APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO.- Write today far complete list of premiums and our special sub- scription offer. "RADIO," Pacific Bldg., San Prencisco, CaL LOUD SPEAKER FOR ANY CRYSTAL SET. Hear music over entire house. Easily con- structed by amateurs. Eliminates Battery. In- structions complete. 23c. Catalogue Free. Rep- resents tires wanted. STEINMETZ WIRELESS MFG. CO. EAST END, PmSBURGM. PA. WE NEED RADIO WORLD, dated April 23 and August 1 II you have copies you don't re- quire, mail to this office and current issues will be sent you for them. RADIO WORLD, 1493 Broadway, New York. EXCHANGE LETTERS with friends everywhere. Pleasant paatime. Information for stamp. Smith, Box 3125. M. Portland, Ore. OLD MONEY WANTED— $2.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave S3, Le Roy, N. Y. WE WANT YOUR NAME— On a postal card. We would like to get the name of every RADIO WORLD reader, as we expect to send out a special message that will interest you. Be sure to send us your nsme on a postal card and ad- dress it, GIFT DEPT., RADIO WORLD, 1493 Broadway. New York. HAVE YOU SEEN ITT My unusual, hrftr 3 luetrated radio catalog ia complete. Saves yst money. N. E. Ristey, Spring Grove, alias, VACUUM TUBES repaired reasonably, IsSt- factioo guaranteed or cost nothing Vsceea Sect., 101. 1621 Derr, Toledo, a A WORD TO THE WISE RADIO WORLD No. 30, dated Oct. 21, pub- lished my hook-up, and amateurs were sttoe ishrd as to results obtsined. Those usisf this hook-up csnnot afford to be without itt Utrit improvements. Those desiring s set SECOND TO NONE snd one having unlimited receiriof range should not overlook this opportunity. Has dreds report hearing stations over 1.500 milei distant on single tube. COMPLETE INFOR- MATION AND BLUE PRINT, $40 (so stamp). Write W. Miller, Box 222, Southern Metbodir. University, Dallas, Texas. MEMORIZE WIRELESS CODE by this J- boor home study course. Price. $1.00. Seat ia ad- vance of price, upon request. Cory don G. Snyder. 1161 So. Ridgeland Ave. Oak Park, EL RADIO PARTS-Low prices. Write for fun. Geneva Radio Co.. 32 Grant St., Geneva, Ohio. 1 .001 Variable Condenser, 43 plate, $250; 1 Fada Crystal Detector, $1.25; 1 Clapp- Eastham, stri H.R. Detector, $28.00, new; I Magnavox, (3SJS, new. Ben Beeker, Oakford, TIL FOR SALE — Clapp- Eastham HR tuners ass HZ amplifiers. Thirty Dollars each. Cash *Hl order. Brand new. original cartons WIRELESS, Box 353. Calais, Maine. DID YOU GET THE XMAS RADIO WORLD! This was our attractive issue of December 1 Mailed on receipt of 15c, stamps or coin— or rob- scribe and have your subscription be|in vitk XMAS number. RADIO WORLD. MH Bressvtr, New York. FOR SALE— No. A- 1 Gorton Encraviaf Et- chine and set of Radio letters, in good conditioa Will sell cheap or trade for radio supplies. L & Hitter, 414 Desderick St, Nashville, Tana. TWO PAGES of U hook-ups of great raise to RADIO WORLD readers appeared ia oar iaaa of Oct. 21 and 28. Both copies seat oa receipt of 30c in atamps or coin, or start year rob scription with Oct. 21 number. RADIO WORLD, 1493 Broadway, New York. Claims Radio Saved City RADIO saved Atlanta from destruc- tion," declares William B. Cody, chief of the Fire Department of Atlanta, Georgia, commenting on the latest ac- complishment of radio in rising to an important emergency. Fire broke out in a block of retail stores in the city's chief shopping dis- trict, a few hundred yards from the At- lanta "Journal" building. It gained great headway before it was discovered, and threatened the entire business section of the city. Lambdin Kay, radio director for the "Journal," was conducting the paper's regular late-evening program. He sent oat a bulletin on the fire and followed with other announcements of its progress. From all parts of the city firemen who were off duty for the night rushed to AMERICAN ELECTRO PHONE CO., Inc. US FIFTH AVENUE, NKW YORK CITY DISTRIBUTORS Full line of Nationally Known Radio Seta And Accessories Discount* ■ ' and dealers. join their companies battling the blaze. They had heard Mr. Kay's broadcast an- nouncement of the seriousness of the fire and rtished to the conflagration. Their quick appearance helped to check the flames. "Radio saved Atlanta," says Cbttt Cody. What Shall I Give HER For Christmas ? The oiggett treat assy toe* most particular about her of refinement, who Is is Los Etoils Skin Food $L3$ L - Are • En - Gel ideal cleanser BUS Kauri Pace Powder (four shades) M SB Rouge Superlative g.OS Jeuneeae astringent fLSf Marvelous wrinkle remover and cleanser. Amber Royal Perfume 14.00 Eye Lash Grower $1.08 $11 J* Mme. Anita Kanti's Christmas Beauty Box Mme. Kanti's wonderful preparations have beat the favorite for years and used by the asanas beauties of both Paris and New York. Among Mme Kanti's personal clients east bs named the reigning stage and screen stars. ABSOLUTE SATISFACTION GUARANTEED beautiful Christmas Box will be delivered prepaid ffw*9wipt Otf ■seeeeeeeeeei =■ $10 MME. ANITA KANTI 47 West 42nd Street, Near Yes* Qty Any individual article in this assortment mallei on receipt of price in plain, tpropesr Digitized by Google

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RADIO WORLD Orange Label Tea Special lOf Tins Ridgways Tea is a man's drink — a beneficial cheery bever- age that has the flavor and the body which red-blooded men enjoy. Also sold in I lb., % lb. and V4lb. TINS A Generous Sample will be sent on request. Address: Ridgways, Inc, Department K, 60 Warren St, New York. raw "»;v. COLD MEDAL San Francisco 1915 GRAND PRIZE SanDieJo 1916 Digitized by Google

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RADIO WORLD GIVE HIM A BOOK AS A HOLIDAY GIFT NEW RADIO BOOKS Telling How to Operate a Radio Set — How to Build a Set — Principles of Vacuum Tubes and Other Radio Problems rriooK-i/p: Ra io Hook-Ups By M. B. SLEEPER A book that gives you not only clear dia- grams for all kinds of telephone and tele- graph receiving and transmitting sets, but simple descriptions of each circuit shown and spaces for notes of results obtained. PRICE 7Sc. Construction of New Type Trans- atlantic Receiving Sets By M. B. SLEEPER There is a peculiar fascination about re- ceiving radio messages from the high- power stations of England, France, Ger- many, Russia and Italy, as well as those located in the Pacific Ocean and the Orien- tal countries. Several types of simple re- ceiving sets for this purpose are described, with detectors and amplifiers to accompany them. Suggestions are also given for oper- ating relays and reproducing the signals on a phonograph. Schedules of operating time for high-powered stations are given. In addition, there is some valuable data on home-made wavemeters for testing and ex- perimenting .PRICE lie. Wireless Telegraphy and Tele- phony Simply Explained By ALFRED P. MORGAN One of the most complete and comprehen- sive treatises on the subject ever published. A study of its pages will enable one to master all the details of the wireless trans- mission of messages. The author explains in simple language the theory and pract ce of wireless telegraphy and telephony. 154 pages, 156 engravings PRICE flM Design Data for Radio Transmitters and Receivers By M. B. SLEEPER The only book that fives tables and data for designing, receiving and transmitting apparatus so that you need no knowledge of mathematics. It s the first book a be- ginner buys after he has learned the use of his phone receiver .PRICE 7Sc Construction of Radiophone and Telegraph Receivers for Beginners By M. B. SLEEPER The man who wants to feel the real thrit of accomplishment, and who is not satisfied in the merely making use of what others have done for him, builds his own radio apparatus. Radio men can follow the data in "Radio Phone and Telegraph Receivers " with full confidence, because each piece of apparatus described was first made, tested and found efficient before the final design was accepted. Special receivers, both crys- tal and auction, are shown in detail. Regen. erative circuits as well as audio and radio frequency amplifiers are described with clear photos, diagrams, and working; draw- ings prepared especially for the navice and the man who wants to receive the radio telephone broadcast. A special feature is the phonograph type radio set ami the loud speaker. Fully illustrated PRICE 7*c. The Radio Experimenter's Hand- book By M. B. SLEEPER Throughout the preparation of this book, one purpose was kept in mind— Answer the Practical Questions of the "Novice,"' of the "Beginner/' and the more advanced "Stu- dent." This book will help in the selection or construction of simple apparatus for the transmission and reception of radio tele- graph and telephone signals. In the chap- ters on radio receivers the simplest crystal, the simple audion, and the regenerative types are described in quite some detail. The question of antennas, both for trans- mitting and receiving, are taken up. A good many helpful suggestions are given which will be of considerable aid to the experi- menter. 16 chapters. Fully illustrated. PRICE n m The A B C of Vacuum Tubes .Used in Radio Reception By E. H. LEWIS L R- E. aa Written particularly for the person who "knows nothing about radio" but who would tike to gain an understanding of the elementary principles of operation of vacuum tubes and various circuits in which they are used for the reception of radio-telegraph signals and radio- telephone music and speech. Illustrated . .PRICE $1jW How to Make Commercial Type Radio Apparatus By M. B. SLEEPER This book describes in detail many com- mercial types of spark and vacuum tube telephone transmitting and telegraph and phone receiving equipment of all kinds. The experimenter wilt be able to get a world of ideas for the design and construc- tion of his next piece of radio equipment from the very clear descriptions and the 98 clearly illustrated figures ..PRICE lie Experimental Wireless Stations By P. E. EDELMAN Tells how to make apparatus to not only bear all telephoned and telegraphed ra<l» messages, but also how to make simple equipment that works for transmission over reasonable long distances. Then there is a host of new information included. The first and only book to give you all the recent important radio improvements, ansae of which have never before been published. 392 pages, 167 illustrations PRICE tXW K^Any of These Books Sent Prepaid on Receipt of Price. The 9 Books for $10.00, to One or Different Addresses. address THE COLUMBIA PRINT ROOM 326, NO. 1493 BROADWAY, NEW YORK Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered u aecond-claaa matter, March M, 1921, at the Pea I Office at New York. N. Y., under the act of March 3, 1179.] \ Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publication* Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. Vol. II, No. 14. Whole No. 40 December 30, 1922 15c. per copy, $6.00 a year The Vice-President Talks by Radio ONE of the most notable radio events of recent date was the broadcasting of three important speeches to the people, by Calvin Coolidge, Vice-President of the United States; John S. Weeks, Secretary of War, and Edwin Denby, Secretary of the Navy. This was the first time that the spoken words of three of the nation's lead- ing executives reached all corners of the country in one day. The broad- casting was done by WGY, of the General Electric Company, Schnec- tady, New York. This fact was made possible by use of the pallo- photophone, a new device for photo- graphing the voice and, later repro- ducing it with perfect clearness. The machine was set up in a hotel in Washington ten days prior to the speech-making. The Vice-President and the War and Navy Secretaries spoke into a small recording-horn. As they did, their voices caused a small diaphragm to vibrate to which is attached a tiny mirror, scarcely smaller than the head of a pin. This oscillation, or flickering, of the mirror reflected a beam of light upon a moving photo- graphic film thus recording the human voice accurately with the overtones, the delicate shadings of speech and other characteristics which make one voice sOund differ- ent from another. The film was taken to Schenectady and was broadcast twice from the WGY studio, the. first time at 7:30 P. M. and again at 10:30 P. M. for radio fans in the Western States. In re- producing, the film is passed before a strong ray of light and the zig zag markings on it which the sound waves photograph, create electric waves which pass through an ar- rangement of vacuum tubes. Digitized by Google

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4 RADIO WORLD How to Make a Single-Blade Vernier By Ortherus Gordon tMrtm THE reasons for presenting •the workshop plans for a single - blade vernier con- denser are many. In the first place, some amateurs may prefer such an instrument over an additional swinging blade on the regular variable, as suggested in a previous article. The present instrument has the advantage of being entirely inde- pendent and may be shifted about from circuit to circuit as needed. It has appeared in this form on the market. I have made one for my- self and am satisfied that vernier control is necessary for sharp and efficient tuning. Incidentally, I was curious to de- termine whether or not the vernier being separate from the main in- strument made any difference. Some local amateurs were loud in their insistence that the distributed effect would be greater than the tuned-capacity effect; but I found out that, if such was the case, it was in no way noticeable. The unit, as it is shown here, is a convenient and well-designed affair. Special pains were taken to make it as simple as possible. All the work may be done with the ordinary tool chest, vise and bench. When finished, the vernier condenser mounts on a panel with the other parts of the receiving set. Mine cost 54 cents, not counting the spare washers and pieces of brass found in my scrap heap. The stator was made first. I took a piece of brass sheeting (although aluminum or copper will do) about 1/16 of an inch thick and marked it as shown in Figure 1. Owing to the semicircular lugs it was impossible to economize on brass. I cut out the two stator triangles with hack- saw and drill, then smoothed the edges and rounded off the corners with a file. When sawing plate brass, put the brass deep into the vise so as to prevent chat- tering Protect the brass with wooden blocks, so the teeth of the Figure* 1 — Complete detail* of the stator plate*, bolts, and bushings tor tbo panel mounting of a single-blade vernier. vise will not sink into the surface. The two stator blades were then put in the vise together and drilled in the center with a 3/8-inch hole, and at the corners with 1/8-inch holes, as shown in Figure 1. Since I was designing the instrument for a panel, I cut three short lengths of brass tubing, 3/8 of an inch long, and large enough in inside diameter to take an 8-32 brass bolt with a flat head. In my case, with a panel 54 1 1 ! u Figure 2 — How to put the stator together. of an inch thick, these bolts were \% inches long. Then I took three aluminum washers (although brass or copper would serve just as well) Yi of an inch in thickness ; and with these accessories, I put the stator together temporarily, as shown in Figure 2. The rotor blade I cut out of thin brass with shears. It is semi- circular, with a radius of 1J4 inches. A ^6 -inch hole is bored in the exact center of the blade, so that it will fit over the reduced diameter of the shaft, which is a J4-inch brass rod turned down to % of an inch at one end and threaded with the popular 8-32 die. The making of this shaft, by the way, is one of the jobs of the instrument. There are three in all; the other two are the making of the fiber space-washers. Everybody isn't lucky enough to have access to a high-speed lathe, but that needn't discourage anyone. The shaft may be built without a lathe in this manner. Take a short length of brass tub- ing, instead of brass rod, and tap one end for about % of an inch down. Then get hold of the ever- needed 8-32 bolt and screw it in until it is solid. Then saw off the head at the required length from the tubing, and presto 1 the job is done! See Figure 3. Now, the two fiber washers, or bushings, are problems. It is too bad they cannot be dispensed with entirely ; but unfortunately, they are vital parts of the instrument. The rotor must be insulated from the stator. Fiber, or hard rubber, or composition of some other kind are the only materials suitable for making the bushings as shown in Figure 3. I worked many hours to redesign the instrument so that these washers could be omitted. Although I succeeded, I always re- turned to the washer idea as the easiest way in the end. I rummaged around in my "odd bits" box and finally came across some old fiber-washers which could be patiently filed until they had something that resembled a shoulder on them. If I remember rightly, it took me two hours to fit those fiber bushings the way I wanted them— to drill them so No. 1 would slide over the J^-inch part of the shaft and No. 2 over the J^-inch diameter. The other details, such as the connecting lugs, explain themselves. The assembly was very simple. The washers go in place as shown in Figure 4, and the rest of the parts placed in the one and only way a variable condenser may be put to- gether. Then it is mounted on the panel as shown. A graduated dial, M.1£HMMt or Figure 3 -Schematic details of rotor and rotor shaft. Digitized by Gougfe*

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RADIO WORLD 5 The Ossiphone an English Device Not Sold Here IN Radio World No. 35, dated November 25, there appeared an article entitled "With the Ossiphone Even the Very Deaf May Hear Radio," by Ortherus Gordon. It described the invention of Mr. S. G. Brown, London, England— a simple instrument which, it is claimed, conveys sound to the brain by enlisting the aid of the bones in the body of the deaf person, hence its name. So many inquiries have come to the offices of Radio World, since the publication of this article, from deaf persons who want to know where the device may be purchased, that the editors wrote Mr. Gordon for further information on this on this point. We publish his letter herewith. — The Editors. EDITOR Radio World: In reply to your query regarding the ossiphone, I am glad to give what further informa- tion I can about that instrument. The ossiphone was invented over a year ago by Mr. S. G. Brown of London. He designed it for use with an in- strument which he called an "aural box" into which a person desiring to converse with a deaf person spoke. This aural box was nothing but a sound-box and microphone, which relayed its vibrations to the ossiphone which the deaf person held in his hand with the knob pressed tightly against a knuckle. Then it was discovered that a radio receiver could be substituted for the aural box with won- derful possibilities for the deaf. As far as I know, the ossiphone has Radio-Wire Tables By Frederick J. Rumford, E.E., R£. No. 5 — Double Silk-Covered Wire Showing the a Pound and Number Fractions of of Feet in a Pound A PPENDED is the fifth of a series of five tables of radio wires which the amateur will find useful for many nurDOSCS Sis* H lb. X lb. K lb. fc lb. 1 lb. 2* 38 78 158 234 312 a 48 88 182 288 388 22 81 122 244 288 483 23 78 158 312 488 831 24 88 188 388 584 778 2S 128 248 728 •88 2* 158 388 888 •88 1282 27 182 384 788 1152 1542 28 238 478 858 1434 1817 2* 318 828 1248 1888 2485 3* 383 728 1452 2178 91 488 828 1848 2788 SCO 32 581 1182 2324 3484 4854 33 711 1422 2844 4288 34 888 1778 3552 5328 nu 35 1888 2132 4284 8388 8534 34 1254 2588 5818 7524 18838 37 1333 *m 5332 7888 18888 38 1777 3554 1 7188 18882 14222 38 2884 4128 8258 12384 18518 48 2888 5332 18884 15888 21333 The following tables' have already been published: No. 1 — Enameled Magnet Wire. Radio World, No. 34, dated November 18. No. 2— Single Cotton-Covered Wire, Radio World, No. 35. dated November 25. No. 3— Double Cotton-Covered Wire, Radio World, No. 36. dated December 2. No. 4 — Single Silk-Covered Wire, Radio World, No. 38, dated December 16. not yet appeared on the American market. I have reasons to believe that it is on the market in England; but an examination of English periodicals does not reveal an advertisement to that effect. I had some inquiries from readers of the Radio World in regard to the manufacture of the ossiphone, and I (Continued from preceding Page) or a plain knob, is added as desired. The instrument is connected either in series or in parallel, the result being the same. I have no idea what the capacity of this home-made in- strument is, but it is small enough to make tuning a critical function. cautioned all to be careful of patent in- fringements. Such an invention at the ossiphone is certain to be protected in every civilized country in the world. There is one man in England who, per- haps, could give information on the com- mercial aspect of the ossiphone. He is Mr. Philip R. Coursey. editor of "Wire- less Age," London. He may even put a correspondent in touch with the inventor. I rralize the immense utilitarian benefit of the ossiphone. Damped Waves in Spark Sending Waves By George W. May, R. E. F! / Oonn(CT-blada v.rnWr coodmMT, as describer by Ortherus Gordon, showing also tbe mannor of Mounting on tlx pan*!. *OR radio telegraphy, sending is accomplished with a high- voltage spark capable of pro- ducing from 150 to 200 sparks a sec- ond. Each of these sparks produces a radio-wave train having from 15 to 25 waves which have a frequency of about 1,000,000. Imagine a space of 300.000.000 meters containing 150 or 200 short-wave trains, equally spaced, the length of each little wave train being very short compared with the space between them. The radio signals would then con- sist of dots and dashes containing a large number of noises made on the receiving apparatus by a larger number of these wave trains; while the dots would consist of a smaller number of wave trains which would produce the buzz for a shorter time.

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6 RADIO WORLD Front and rear views of the set designed and constructed by Edward Pina. The utmost care was taken in its construction. All the work waa done under conditions which might impel the average amateur to doubt. It is worthy of note that, in point of construction, there are few seta that as it. Note the specially designed anticapaclty directly above the amplifying transformer and between the two condensers. The honeycomb coils were designed and hand wound by the builder especially for abort-wave work. Prize Set Built on Kitchen Table FOR originality and clever wiring there is much to ad- mire in the set, described in this article, the work of Mr. Edward Pina, an amateur, residing at 326 West 20th street, New York City. All the work on this set was done on the kitchen table of his home, without the use of any tools except those generally found in an ama- teur's shop. It serves to illustrate how an amateur, if he is a careful worker and takes his time, can con- struct apparatus that is comparable to many of the manufactured sets in point of construction. The fea- tures of this set are: By John Kent Panel made of special hard fibre. Original anticapacity switch con- trolling, independently, the detector and each amplifier without the use of jacks and plugs. Specially wound honeycomb coils for reception on 360 to 400 meters, 600 to 800 meters, and so on. Flexibility by the use of series parallel switches. In the rear view of the set may be seen the special anticapacity switch, located right over the transformer. It is constructed in such a manner that the detector is connected at all times while the amplifiers are thrown in or out as desired. All leads are materially shortened by use of this switch. It is an enor- mous help in short-wave work. All the variable condensers are equipped with clips which allow small fixed-condensers to be placed in parallel with them. This allows a fixed increase in capacity which, the builder has found, helps con- siderably in short-wave work. This set won a prize at the Eve- ning Telegram Radio Show, held in the 71st Regiment Armory, New York City, last May, before it was 6 Volts- Schematic diagram of the connections of Edward Pina's set The anticapacity switch is shown on the upper portion. It is so arranged arms of the detector are connected either to the phones or the first stage of amplifier. By reason of the fact that the arms of the ai wider, they permit the second step to be connected in by just a slight turn of the handle. A fixed condenser is shunted secondary-condenser and, also, across the primaries of both amplifying transformers. that the switch aplifier side are the regulation Digitized -p-v by Google

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RADIO WORLD 7 Construction of a H-volt Wet Cell By Robert L. Dougherty IN the past few months, the volt tube has come into general use. One of the great draw- backs in using a dry cell in connec- tion with this tube is its short and uncertain life. You may operate your set, to-night, on the dry cell and suddenly find that your battery is going "dead," and you will miss a fine concert just because you have no other battery on hand — and all the stores are closed. While the wet cell has its draw- backs, if it is placed in a conspicuous place it is not as attractive as a manufactured dry-cell with its nice- ly printed outside cover, but it has the advantage of being fairly con- stant. If care is taken to remove the elements after using the cell, and washing them in water — which is an easy matter — it will last many hours longer than any other dry cell. Its elements can be easily and cheaply replaced. There are two kinds of batteries that will lend more readily to home construction than some of the others — salamoniac and sulphuric-acid cells. In the salamoniac cell there is not the danger generally attributed to the sulphuric-acid cell, although the elements used in the construction of both cells are identical. The necessary materials are 2 car- bon rods, about 5 inches long and x/i inch in diameter ; 1 standard wet- battery zinc,; a small fruit jar, or Figure 1. Diagram showing how tho thro* boles should bo bored in tho block of wood in the con- struction of a lH-voit wet cell. Tho comet measurements and fuids Unas are also given. The wood majr be cut la circular shape, the exact fit oi the Jar, If a neater-appearing article ia desired. large tumbler ; a few ounces of sala- moniac, and a piece of wood. Drill the wood in the same man- ner as shown in Figure 1, and put the three elements in the two car- bon rods on the outside and the zinc in the center. It is best that the carbon rods be held in place by a couple of wood screws, as this will make it easier to connect them. The carbons may be connected by a nar- row metal-strip.. Fill the jar about three-quarters full with water and add the salamoniac until no more will dissolve. The completed ele- ment is then immersed in the solu- tion and the battery is ready to con- nect up. Such a cell will furnish \y2 volts. Where it is advisable to make a neater-looking job, the wood may be cut in circular shape, the exact fit of the jar. The second battery uses a sul- phuric-acid solution, in connection with an element made identical to the one above. Sulphuric acid is a dangerous material if not handled carefully. If spilled on anything, it will eat in quickly. In case of such an accident, wash immediately with ammonia. Be sure that you don't mix any of the ammonia with the solution in the battery. The solution should be made Up as follows : One part bichromate of potash, 1 part sulphuric acid (10 per cent solu- tion) to four parts of water. Fill the jar about full with this solution. Put in the elements and the cell is ready for use. Always be certain to pour the acid into the water, otherwise the acid will spatter due to the heat generated in the chemical- action. The only replacements are occa- sionally a zinc and a carbon element, and a few drops of water as the solu- tion evaporates. Any number of these cells may be hooked up in series for any voltage wanted. (Continued from preceding page) completed. It won on points of con- struction alone, as it was not com- pletely wired when exhibited and could not be operated. The panel is supported by upright brass standards fastened to the base- board and running completely around the outside of the panel. It took over three months to con- struct this set, Mr. Pina working from 7 until 10:30 every evening. This will give the reader some idea regarding the pains taken in order to perfect it. Every article used is of the finest make. "Any amateur," said Mr. Pina to the writer, "with a little time and trouble, can construct apparatus. The only thing necessary is ability to handle tools and patience to do a good job thoroughly." Subscribe for RADIO WORLD, $6.00 a year. $3 00 six months, $1.50 three months. B. of S. New Radio Work Directive Radio- Transmission Tried on ■ Wave Length of Ten Meter* THE enormous increase in the use of radiotelegraphy and telephony dur- ing the past two years has created a der mand for apparatus capable of being op- erated with a minimum of interference. Wherever the need is not for broadcast- ing but for point-to-point communication the case seems hopeless, unless directive transmission can .make it possible. Di- rectional transmission on very short wave lengths (below 20 meters) may offer a solution to this problem. Recent reports by Marconi, Franklin, and others show that interesting and val- uable data have been obtained on di- rective radio transmission using wave lengths below 20 meters. The Bureau of Standards has just completed a series of similar experiments, the preliminary re- sults of which confirm the work of these investigators. The experiments conduct- ed at the Bureau of Standards were made with a parabolic reflector (cylindrical type), which was designed for a 10-meter wave length. It was made by construct- ing a parabolic wooden frame with an aperture of one wave length. This frame was suspended in the air and 40 wires spaced 1 foot apart were suspended from it. The source, located at the focus, con- sisted of a 50-watt electron tube. The output from this tube was coupled to an antenna, which was a linear oscillator of the Hertzian type, which was tuned to a wave length of 10 meters. The com- plete reflector system was arranged so that it could be rotated. Numerous polar curves were obtained by rotating the reflector and taking read- ings of the received current at every 10* position of the reflector. The receiving apparatus was located 170 feet from the reflector in most of the work and con- sisted of a loop antenna (single turn) with a thermoelement in the loop cir- cuit. A portable galvanometer was con- nected to the thermoelement. With all adjustments correctly made at the reflector, good directional transmis- sion was obtained. With the reflector turned 20 degrees from the direct line to the receiver, the received current dropped off to one-half of what it was with the reflector directed to the receiver. There was practically no radiation over an angle of 270 degrees, while the majority of the radiated nower was confined to an angle of 30 degrees. Digitized by Google

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8 RADIO WORLD 98 Stations Now Send Weather News United States Government Radios 8,000 Words Daily of this Important Information. One Great Lakes Station Handled 150,000 Words from June to December IN order to get an idea of the immensity of the weather broad- casting carried on daily, an estimate of the number of words transmitted daily by the Govern- mental stations is fixed at 8,000. A reduction is made on Sundays, when approximately 6,000 words are handled. At the Naval station at Altena, Illinois, approximately 150,- 000 words are handled during the Lake shipping season between April 15 and December 15. This is one of the largest traffic schedules of the whole system of 98 stations. Radiotelegraphy, although • an in- valuable factor for several years in receiving and sending data on weather to and from ships, was not recognized until recently as a medium for the general dissemina- tion of forecasts, according to Pro- fessor C. F. Marvin, chief of the United States Weather Bureau, in his report to Secretary of Agricul- ture Wallace. The use of radio by the bureau, throughout the country, was limited because of the necessity of using code, he explains. "With the intro- By JV. R. Service duction of radiotelephony, which makes it possible for anyone to re- ceive the messages in spoken words, the broadcasting of information over the interior has increased enor- mously," he declares. A year ago, the daily forecasts of the Weather Bureau were broadcasted from twelve stations in seven States, principally by radiotelegraphy ; whereas, on July 1, 1922, ninety- eight stations in thirty-five States were carrying daily weather fore- casts and warnings chiefly by radio- telephone. Government and Private Stations Used All broadcasts are sent out from governmental, commercial, and private stations, without expense to the Bureau. A special wave of 485 meters has been assigned by the Department of Commerce, and to avoid interference and duplication, only two stations in a city are licensed to transmit weather in- formation, although many others Congressman Fess Makes Radio Speech (C. National I'boto and Wide World Photos) Conrressman Simeon D. Feaa, of Ohio, about to make a speech by radio, in the House of Rep- resentatives. At the right is the microphone to catch his remarks. This is not to be a regular It was simply a "try-out." And it worked. would gladly cooperate. It is estimated that, at the end of the year, 25 per cent, of the licensed broadcasting stations were engaged in distributing this valuable meteor- ological information. The broadcasts are supplied to the radio stations from neighboring meteorological stations by telephone. Undoubtedly the service could be placed on more efficient basis and materially ex- tended, the Chief of the Bureau states, if funds were available for telegraphing information to radio stations not now included in the system, and engaging more em- ployees. The value of radiotelegraphy in this special service has been demon- strated, Professor Marvin declares, pointing out that its future useful- ness "cannot be estimated." Hun- dreds of farmers who do not get a forecast service by the telegraph, or through the daily press, and for whom code broadcasting was of little use have installed receiving sets during the year. They now ob- tain the weather forecasts and warn- ings, so important in their occupa- tions, as promptly as do business interests in urban communities. A great future increase in rural receiv- ing stations is inevitable, the weather officials believe. Another important accomplish- ment in radio work during the past year, was the inauguration of a program of broadcasting the twice- daily forecasts, cold wave, frost, and other warnings and information issued for the States lying in the Chicago and Washington forecasts districts. From April to November, a summary of weather conditions as they affect the crops during the week preceeding is also included. This service began in June, 1922. Radiotelegraphy and high wave- lengths are utilized, as telegraphy is more reliable for long-range trans- mission. The radio-receiving sta- tions, equipped for high-wave re- ception, receive a direct service thereby, and local radiophone sta- tions are enabled to broadcast for their districts. Material extensions were also made during the year in the radio-bulletin service for the benefit of marine and aviation interests. The chief of the Weather Bureau is gracious in his thanks to the officials of the Naval Communi- cations Service Digitized by Google

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RADIO WORLD 9 Peanut-Tube Hook-Ups I Have Used Successfully Flfor* 1 8ch— tie dUcram auccastad by Mr. Matzlar. Note that tha and« of tha primary and aacandary ar* connactad (or Ana tuning. Tba aaa af tha ticbJar call, is conjunction with tha i aril— In, ffvaa • vary aalacthra circuit, aad ana that aarUlataa (raaly. Drawn by S. Nawman. MANY diagrams have been published of hook-ups em- ploying standard makes of vacuum tubes— both detector and am- plifying tubes. I will describe a few hook-ups employing the Welsh relay radion or "peanut" tube. The more I experiment with this little tube, the better results I have secured, espe- cially using it as a detector tube. The construction and arrange- ment of the coils used in these hook- ups were fully described in my article in Radio World, No. 26, dated September 23. In Figure 1 accompanying this article, you will note that the end of the primary and the end of the sec- ondary connect to the filament. I might suggest that a switch be placed here so as to disconnect the primary and the secondary at will, as with the connections shown it is more difficult to tune as it is much sharper. While the spark stations are not operative let this connection remain loose; but when one starts up, make this connection which prac- tically cuts them out. Note that no grid leak is used with this hook-up. In Figure 2 either a vario-coupler or a loose coupler, may be used. A ' variable condenser also may be used in the primary circuit to great ad- vantage. You will note that this is a little different from the other hook- ups using two variometers. The one in the filament end of the sec- ondary makes it much more selec- By P. F. Metzler 1. 0005 Mf, Grid Leak fly' Double Circuit Jqck Single Circuit Jockey. FI«ara *— As la Not* aba that t Fl««ra I. tha aaa of i af tha i tive and also helps to make the cir- cuit oscillate more powerfully. In Figure 3 the grid leak leads to the filament and does not shunt the condenser. This arrangement was found most satisfactory. In both Figures 2 and 3, there are but 18 volts used on the amplifying tube for the plate votlage. This is, of course, operated with Welsh radion relay. I have been successful with all of these hook-ups. For instance, on the night of November 29, I heard WZY, KDKA, WJZ, WBAP, WHK, VVHAS. WMH, WGM, 2XC. WOC. 2XY, WSB. WFAT, WIGR. WJAH, and WMAB.

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10 RADIO WORLD Broadcasting Most Important Factor in Nation's Existence "We Arc on the Threshold of a New Era Which Will Probably Affect Our Modes of Life"— Maj.-Gen. Squier, U.S.A. WASHINGTON, D. C— Radio development advanced several lengthy strides dur- ing the past year through broad- casting, technical research, and the application of advanced design to military communications, according to the annual report of Major-Gen- eral George O. Squier, Chief Signal Officer of the United States Army. Through the operation of the Army radio net, established in May, and numbering 60 stations on November 30, the Signal Corps saved the Government $14,357 in the transmission of official communica- tions, over what they would have cost at commercial rates. These radio stations established in Corps Areas in Continental United States and in their subdivisions handled a total of 40,494 messages in the seven months of operation, cooperating with Naval coastal radio-stations in some instances. Broadcasting Outstanding Feature of Past Year The Army radio stations at Nome, St. Michaels, Holy Cross, and Iditarod, Alaska, have been re- habilitated. New and powerful sets with a range of about 150 miles have been installed at Nulato and Wrangell. Signal Corps installers were working at the Noorvik, Mc- Grath and Bethel stations, and equipment was en route to Fort Egbert and Ruby, at the end of the fiscal year. Equipment for the Craig station was also available, leaving only three stations in the territory awaiting new apparatus. "The outstanding feature of the year in signal communication un- doubtedly has been the phenomenal development known as 'broadcast- ing'," says General Squier. The sud- denness of this development, he be- lieves, has no parallel in the applica- tion of science to everyday life. "In the educational field alone," he states, "we are on the threshold of a new era which will probably affect our modes of life." Pointing out the importance of radio communication in both peace and war, the chief sig- nal officer explains that the Signal Corps is endeavoring to keep abreast of all developments with a view of utilizing and assimilating them for Army purposes. The experiments, conducted in his office, in broad- By Carl H. Butman casting over electric-light lines in an effort to reduce the interference in the ether, and with the "super- phone," a method of secret line- radio communication, are cited as examples of practical experiments undertaken recently. Radio Research and Development Although handicapped by both a reduction of funds and personnel, the division of the Signal Corps en- trusted with communication, re- search and development, completed 78 new specifications of radio sets and apparatus, together with 300 drawings during the year. Among the accomplishments in radio engi- neering was the perfection of a new radiotelegraph set for infantry bat- talions for communicating with regimental and corps headquarters. This set has a five-mile radius and employs waves between 75 and 77 meters, but is capable of ten set- tings, or different notes, between its extreme waves. One of its ad- vantages is a portable square loop, about 9 feet, which may be folded. It also has directional features. These sets are now in production for the United States Infantry Corps. Another set, designed espe- cially for division or corps head- quarters, employs six 250-watt tubes in transmitting. This gives a tele- phone range of about 100 miles and Don't It Get Your Goat WHEN you have decided that It Is • fine nicht to listen for DX end then find that your storage battery ^Undischarged? When you so all the way downtown to (at some specific piece of apparatus, to find that all the stores are "sold out r When you are telling someone that you got Davenport, Iowa, so nice and clear, to have a feUow come along and say: "Oh, that's mrthln ! I «et him so regular that 1 don't listen for him no more. I only listen for DX fellows now." When you think that you are using an en- tirely original hook-up to find that it was dis- covered so long ago that It has whiskers? When your a*rl gets peeved and says: "You're always broke, buying thlngamagumies for that radio. I like to go out ^ once in a while?" You're as blue as can be. The first thing you tune in is XYZ playing ^"Good-by, Summer?" When the new set you built doesn't give you as good results as your ^ old "piece of Junk?" When nobody appreciates the fact that you ~ coda once in a while, and kick when like to read you don't let hear the local broadcasting? a telegraph range of practically 600 miles. The set is portable in that it may be mounted in tractors for field transportation. A tube set was developed for use in permanent sta- tions with two 50-watt tubes op- erated from storage batteries for both telegraph and telephone trans- mission. The sending and receiving units are separate and the range is about 150 miles. Progress of Aircraft Radio Work For the Air Service, two 100-mile " range telephone and telegraph sets were especially developed, one for large airplanes like the Martin bombers and the other for use at ground, or base, stations. The ground-station apparatus uses two 250-watt tubes in place of ten 50- watt tubes. Since June 30, contracts for the development of both these designs have been let to commercial electrical companies for completion. The perfection of a 5-mile range set for interplane communication em- ploying the Armstrong receiving system and intended to be used on pursuit planes in formation flying, has also been placed in the hands of manufacturers, due to lack of Signal Corps personnel. Contracts have been awarded for the production of a number of new airplane radio sets with a 30-mile range, using two 50-watt tubes. The apparatus is split up into several units which are distributed in the plane and controlled from the dash- board by the pilot. Work on a radio- telephone mule pack for use in mountain artillery was also under- way, but uncompleted at the close of the fiscal year. Considerable progress in the design and testing of a radiotelephone set for use in Army tanks was accomplished. The de- velopment and test of a 5-station interphone set for use in the Martin bombers is also progressing. Other developments included work on a field-telephone repeater for use in coupling line and radio communication, especially in balloon communication; the perfection of a direction finder for the Coast Artil- lery Corps, and tests with the resonance wave-coil antenna for the elimination of static, revealed that where large antenna cannot be erected, on portable sets, this ap- paratus may be of great advantage. Digitized by Google

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RADIO WORLD 11 The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks AAME the four common meth- ods of producing electromotive force.— (E. M. F.) Electromotive force is most com- monly produced by the following means: friction (static electricity); chemical action (ordinary battery) ; motion (dynamo and alternater) ; thermal action (thermo junction. Two dissimilar metals and application of heat.) * * * W hat is an ohm? An ohm is the unit of resistance. The international ohm is measured by the resistance offered to the flow of an unvarying electric current through a column of mercury 106.3 centimeters long, weighing 14.452 grams, at a tem- perature of 32 degrees (F.). * * * What is Ohm's law? The strength of the current in am- peres in any given circuit is directly proportional to the E. M. F. and in- versly proportional to the resistance, as in the equation volts (E) Amperes (I) equals resistance (R) is generally written as follows : E 1 = R Illustrated by problem : Voltage in circuit 12 ) _ amperaee 6 Resistance — 2 ohms) Apply the same principle where the resistance and amperage is known. Thus, where E = I X R- Problem : Amperage is 4 ; resistance is 3 ohms. Find voltage. Amperes 4 Resistance X 3 Voltage 12 Apply same when voltage and am- perage are known, to find resistance. E Where R = — I Problem: Voltage is 110, amperage is 5. Find resistance in line. Voltage is 110-t-S amperes =22 ohms * * * Explain three ways in which batteries may be connected and show a diagram? In series; in parallel; in series parallel. Figure 1 IS' I.* * ■B- t.sY /.sy The thru diagrams showing how batteries may be connected. Fully explained In accompanying article. Figure 1 shows the cells con- nected in series. When the cells are connected the total . E. M. F. (voltage) is the sum total of one cell multiplied by the number of cells in the circuit. But the strength of the current (amperage) will not exceed that of one cell and will probably be less because of the internal resistance of the cells themselves. Therefore: with two cells in series, the voltage of each cell is 1.5, and the voltage is 3. Assuming that the circuit is capable of delivering 20 amperage, the sum total amperage of the cells in the circuit is only 20. By connecting cells in series, therefore, we increase the voltage, but not the amperage. Figure 2 shows cells connected in parallel. When the cells are con- nected in parallel, the total E. M. F. (voltage) is no more than that of a single cell itself; but the current Worth Knowing WHEN an amateur is construct- a set, he frequently runs into difficulties when he is mounting his condensers. If he doesn't remove one of the end plates to get the holes straight, he is apt to get his holes drilled out of alignment. The result is that the condenser is generally held to the panel by one screw in- stead of three. A little trick that will remove the objection when the end plate is removed — which gen- erally means over an hour's work when the plates get out of alignment — is to get a fairly stiff piece of card- board and make a hole for the shaft. Then with the drill find the holes that the screws fit into and puncture the cardboard in the direct center of each hole. You will then have a temporary template that, while not as exact as one made of metal, will be, if carefully done, sufficient for all needs'. * * * Use Double Pulleys \X HEN the average amateur is » » putting up an aerial from 100 to 150 feet, he generally is unable to pull it in tight enough to get it absolutely level. The result is that it is , generally slack, due to the weight of the wire. A good plan is to use two double-pulleys. When these are used, it will enable anyone to exert an enormous pull on the wire. Approximately four times the pull may be exerted on the wire then if a single pulley is used. One pul- ley should be attached to the pole and the other to the insulator. (amperage) is that of one cell multiplied by the number of cells in the circuit. Therefore: with two cells in parallel, the voltage of each cell 1.5, and the total voltage is 1.5. Assuming that the circuit is capable of delivering 20 amperes, the total amperage is 40. By connecting cells in parallel, we increase the amperage, but not the voltage. In figure 3 the cells are connected in series-parallel. When the cells are thus connected, the total E. M. F. is that of the cells connected in series, and the amperage is that of the number of cells connected in parallel. Therefore: with six cells connected in three groups of two each in series, with three groups in parallel, the total voltage is that of the cells connected in series and the current is that of the groups con- nected in parallel. Voltage of each cell, 1.5; voltage in circuit, 3. As- suming that the cells are capable of delivering 20 amperes, the amperage is the total of the three groups of cells, 60. Digitized by Google

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12 RADIO WORLD Latest Device to Send Speech by Radio By S. R. Winters * Front view of electron-tube transmitter of completely modulated wave*, described in the accompanying article. SPEECH modulation of radio- frequency currents is respon- sible for radiotelephony and its fascinating applications. The vibrations of speech are complex and the task of any form of tele- phony is to faithfully copy, or re- produce, electrically, at the receiving point the sound wave voiced at the transmitting station. The telegraph key, used in the transmission of dots and dashes, is the visible difference between radiotelegraphy and radio- telephony. In the latter mode of communication, the telegraph key is displaced by means capable of varying the antenna current em- ployed in transmission to harmonize with the sound waves of the voice. A carbon microphone is the device commonly employed for this pur- pose. Credit for a new invention belongs to Lewis M. Hull of the Radio- Communication Section of the Bureau of Standards, United States Department of Commerce. The ap- paratus has been vested with such structural features as to command attention in three particulars: The possibility of operating an electron- tube transmitter from the exclusive sustaining strength of an alternat- ing electric-current source which compares favorably in efficiency with similar sending apparatus utilizing direct current; the require- ment of a high-voltage generator or battery is obviated; and, finally, it has the additional virtue over a con- tinuous-wave transmitter in that the I communications transmitted thereby may be received over a limited distance by use of a non- oscillating detector. The applica- tion of this apparatus in fog sig- nalling and direction finding expe- riments held at the Bureau of Standards have proved the above claims. This transmitter employs a type-P pliotron tube. The plates, as well as the filament, are fashioned of tungsten and the former are stamped with rings having a common center, to avoid twisting or bending when subjected to excessive heat. A com- panion unit of the type-P pliotron tube, in the operation of this trans- mitter, is a 500-cycle, 150-vOlt alternator. The power output of this storage-house of electric energy exceeds 200 watts in an antenna hav- ing from 8 to 15 ohms resistance and a natural wave-length below 200 meters. The adjustible wave-length range extends from 500 to 1,000 meters. The result is the ability to radiate completely modulated elec- tromagnetic waves, rendering feas- ible their reception by means of crystal detectors. The original ex- perimental unit was designed to op- erate at short wave-lengths. The compensating winding of the filament-circuit transformer, illus- trated in one of the photographs, consists of 100 turns of No. 16 wire, with a tap every dozen turns from 30 to 100. The filament rheostat lends itself to service in adjusting the filament electrical-impulses for any steady value of primary voltage on the transformer. The series com- pensating winding also makes it practical to adjust the transformer to the source of electric supply in the circuit so that the filament strength may attain a safe maximum when the load is thrown on. The in- ventor of this transmitter suggests that if ample power is available from the generator it is advisable to overcompensate the transformer, thereby rendering it possible to heat the filament at curtailed electric consumption except when the key is pressed. The incorporation of the series compensating winding in the filament transformer was considered Filament transformer showing- compensated winding used in connection with transmitter of completely modulated waves. Digitized by Google

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RADIO WORLD 13 Radio's Benefits for All Classes of Humanity By /. Andrew White Chairman of National Radio Week Executive Committee SINCE broadcasting started, I have received thousands of let- ters from radio fans and, quite nat- urally, I am in position to know what radio means to the average person. Take the blind, for instance, it has injected new hope into their lives; it has become a bright spot in the darkness that is their lot; it brings to the sightless the newspaper, the book, the theater, opera, concert, and lecture platform, which, in the ordinary routine of their lives, is denied them. True they may be led through the streets, but how much better it is to bring to them the things denied by others. A blind person must be unusually gifted, in- sensitive to public pity or annoy- ance and amply financed if he or she is to take advantage of the re- (Contmued from preceding Page) essential by reason of the fact that the 500-cycle voltage, when employ- ing a 2-kilowatt alternator, dropped enough to lessen the filament cur- rent to the extent of 15 per cent when the electric burden was thrown on in the plate circuit An examination of the perform- ance records of this transmitter re- veals that communications trans- mitted through it were received through distracting interference at a distance of 225 miles, when a 6- foot coil antenna, detector and am- plifier were in service. Signals from this transmitter, which sup- plied 5 amperes antenna current to an antenna approximately SO feet high, in Washington, D. C, were copied at a range of 100 miles by employing an antenna 60 feet high, with an audibility of 10,000, using an autodyne receiving-circuit with two stages of audio- frequency ampli- fication. Automatic • Sender To /SOU* SOOCych Generarfor nmmm Schema be design of the circuit <U«crlW by Mr. S, R. Wintersi (A) Flat* and grid continuous coil wound on fiber tube S% in dm in iHamitn ; M turns No. U mU win one-eighth lack apart; and tap* brought out every S turn* am grid elds aW ran *• on plat* do* of coil. (B) Antenna switch. (D) Generator field rheostat. (E) P pootron. (F) Antenna coil; M turns. Btxendraht, wound on fiber tubs *H taps brought out every 2 turns; mounted so as to slide over coupons; call a* vary mutual Inductance. (C) stopping condenser; mica; C — 0 004 uf. (H) by direct-current motor, which is supplied from the field circuit alt (I,) Filament ammeter. (R) Filament rheostat. (T) Supply ratio of turns e»/l; full-load voltages Ms sSes. (TO Filament transformer, special can. shown ta detail in Fig. S. The main windings consist of 2M turns No. Ud.cc wire i primary aide, connected across the US- volt supply, and 12* turns No. Md.cc wire on secondary side, connected to filament circuit. Drawn by S. Newman. sources of modern society. Only the newest of these resources, radio, brings easily within the ken of the blind all that may be represented by the spoken word or musical sound. When we realize that there are nearly 53,000 blind persons in the United States, we can understand that radio means a great deal to them. Take the case of Carlos Escalante, which came to my attention some time ago. He had been an active business man and had traveled widely. In 1920, he was attacked by a sudden illness and his eyes failed. For a year and a half, he sat in darkness with memory as his only muse. In the home where he once strode confidently, he could but stumble uncertainly with out- stretched arms. Last Christmas, one of his old friends gave him a radio set. It was a godsend to the man. Those of us who rush about daily can only dimly appreciate the joy that radio brought to him. Take the shut-ins. Only those of us who have gone through a long seige of sickness can understand what the radiophone means to those confined to their beds day after day. It actually hastens recovery, since it tends to relieve the mind of worry. The mind has a powerful influence on the body, and often the patient's own mental condition is the chief obstacle in the way of an early recovery. Dr. W. E. Jacobs, medical super- intendent of the Cumberland Hos- pital, Brooklyn, New York, recently commented on this subject: "Radio," he said, "deserves to be ranked with the best mental therapeutic agencies. In fact, for hundreds of cases the radio telephone can be prescribed as one of the best treat- ments." Broadcasting has brought the mountain to Mohammed; the bed- ridden may now enjoy the opera, the drama, and the lecture. Little sufferers may now be lulled to dreamland and relief from pain by the calming influence of lullabies and bed-time stories. In considering radio we must not forget its place in prison reform. Only recently was radio placed in Sing Sing. Warden Lawes made the following statement : "What the future will hold is difficult to predict. The radiotelephone cannot be an instrument for anything but good ; for that reason, if no other, every effort will be made to find a permanent place for it in prison life. I believe its greatest value will lie along mass educational lines. The men hearing addresses made by prominent persons in many parts of the country will gain invaluable in- struction."

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14 RADIO WORLD Radiograms The Latest Important Radio News Briefly Told for the Growing Army of Radio Fans THE "Missouri Broadcasters' Association" has been or- ganized, seeking to eliminate radio interference in the interest of transmitting stations and owners of receiving sets. Their rearrangement of broadcast schedules eliminates prac- tically all of the troublesome interferences which have been increasing for the past three months among Missouri broad- casting stations. This reorganization of radio programs doubles the value and service of the average receiving set, and marks a new boost resulting in increased demand for complete sets as well as for the assembling of home built receivers. The officers of the Missouri Broadcasters' Association are Jedell Mayes, president ; Leo Fitzpatrick of Kansas City, secretary. * » » Radio will carry the inaugural address of Governor-elect Al- fred E. Smith throughout New York State on January 1. Trans- mitting apparatus will be placed in the Assembly Chamber, where the ceremonies will be held, amplifiers in the Senate Chamber and on the Capitol steps will transmit the address to the assembled crowds, while thousands of private radio stations will receive the message broadcast. * * * A cable was sent recently to the amateurs in England to tune in their radio instruments on the 360 meter wave length to listen to H. Gordon Selfridge, jr., who broadcast from the Radio Cor- poration— Westinghouse Station WJZ at Newark, New Jersey. Mr. Selfridge, jr., assistant manager of the Merchandising Di- vision of the Great London Store, is on a three months' tour in the United States investigating die methods of the American department stores. His father, Harry Gordon Selfridge, is a post-graduate of Marshall Field & Company, Chicago. Mr. Selfridge, jr., on his return trip from the Pacific Coast heard a concert from WJZ while he was in Kansas City. He hopes that this experiment will result in establishing really satisfac- tory reception of an American station in the British Isles. * * * Slackers in church contributions are not going to be able to hide behind" the radio set. According to the sfize of a check received by a New York church after the broadcasting of one of its services the radio audience is more deeply touched than the church audience. From one little family which listened in The Beginning- of a "Bug" By R. L. D. (With Apologies to K. C. B.) JUST THE OTHER night, • » « I MET a friend of mine • # • I HAVEN'T seen in years; • • * AND, OF COURSE, we told each other • • * JUST how much • • • WE THOUGHT each had changed, • • • AND HE invited me • * • UP TO his house • • • AND I ACCEPTED the invitation. • • * I WAS introduced • • • TO HIS wife • * • AND his son • • • AND LITTLE daughter. • • • AND HIS RADIO SET— • » * HE TRIED to get^ me INTERESTED in • * • IT but I couldn't • • • SEE HOW any grown man • • • COULD SIT at a table • • • LIKE HE did AND FOOL with a lot of knobs • • « AND FIDDLE WITH levers • * • UNTIL I heard a man • » • TALKING, AND he said: • • • "THE NEXT selection played BY MISS SMITH will • • * BE 'MEDITATION' from 'Thais.* " • • • AND THAT IS mv favorite • • *• PIECE OF music. • • • AND IT WAS SO • • • • WONDERFULLY clear and • • • NICE that when MISS SMITH finished • • • I APPLAUDED loudly, • • # AND THEY laughed at « • • MEt • * • AND, anyway, next * • • # WEEK I'm going • • • TO BUY A BIG --ne FOR MYSELF alone. on the church service came a check for $11.35. Multiplying this amount by the number of families to whom the radio church service has become an establishment it is seen that the total represents more money than is taken in by all the churches combined in a year's time. ' * * » President Scripps, of the United Press, has started out on a two years' cruise of the world, accompanied by radio. He will make the voyage on his 152-foot yacht, "Ohio," which has a cruising radius of some 9,000 miles. The first stop will be Jack- sonville, Florida. A 2-kilowatt spark transmitter and a com- plete receiving equipment have been installed on board and are in charge of J. L. O'Connell, operator. Mr. Scripps wants to keep in touch with the world. * * * A young-lady singer participating in a broadcast concert at Anaconda, Montana, was heard by relatives at Alert Bay, 2,000 miles away. They were greatly surprised when, listening in, tiiey heard her voice for the first time in five years. * * * Radio operators on ships in the Pacific tune in on Honolulu station for the midnight time-signals, and then by a quick ad- justment catch the noon time-signals from Nauen, Germany. » » » The Public Health Service wishes to learn the extent of its radio audience through an appeal to all who "listen in" on its broadcasting programs to communicate by post card to the Surgeon General, Public Health Service, Washington, D. C. Officials of the service declare that they believe theirs is the greatest radio audience in the world, as health programs are regularly broadcast from ten different stations scattered from coast to coast,. but they desire to back up their belief with facts. * * * A musical program, broadcast from WGY, Schenectady, New York, was plainly heard at Cherbourg, France, by the chief radio-operator and others on the steamer "America" while the ship was at dock in that port. Dr. W. R. Whitney, director of the General Electric Company's research laboratory, who is traveling abroad, talked with Chief Operator Black of the "America" and learned for the first time that WGY had suc- cessfully bridged the Atlantic. According to Dr. Whitney, Op- erator Black stated that a concert from the Schenectady sta- tion had come in so well that when he removed the telephones from his ears and laid them on the table in his room the music was plainly audible to those nearby. Cherbourg is 3,100 miles from Schenectady. This .feat establishes a WGY record for transmission to the East only. This station has been heard in Hilo, Territory of Hawaii, which is 5,200 miles from Schenectady by direct air-line. * * * KGB, the Tacoma, Washington "Ledger"- William A. Mullins Electric Company radio broadcasting station, is inaugurating a novel feature. It is planned to broadcast weekly reviews of the current leading radio periodicals and books, published in the interim, reading these reviews over the radiophone on a regu- larly assigned day each week. The reviews will be prepared with care by a staff of three — two radio experts to digest the material and a newspaperman to write the reviews. » * » Radio added luster to the "Tree of Light," the huge Christ- mas tree annually given a place in Madison Square, New York City. The Radio Corporation of America installed a set in the branches, with several powerful voice projectors. The special program from WJZ was given, and thousands heard radio for the first time. * * * The present laws governing radio transmission in England and France prohibit their amateurs from using more than ten^ watts, which limits their range, but on December,21, when they* began transmitting their signals to American amateurs, they were permitted by their governments to use 1,000 watts, which will enable them to participate in the tests involving two con- tinents. The French amateurs transmitted on wave lengths be- tween 180 and 300 meters. As Coue Might Say:— "Week by week, in every way. Radio World is getting better and better." Digitized by Google

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RADIO WORLD IS Radio and the Woman By crystal d. Tutor A FRIEND dropped in the other day. set, she made a wry face and said: Spying my radio "Oh, mercy I has your husband one of those things, too? My Joe bought one about two months ago, and since it is working, he comes home, rushes through his supper and then goes and puts those S hones on — and he doesn't budge until about twelve o'clock, [e is as talkative as a stone; and every time I start to say something, he either shushes me or else looks with that far- away look. It's simply terrible! It's worse than living with a mummy.'' I wonder what she would say if he didn't have the radio "bug" and went out every night. She should be glad that she has something to keep him home. • * • WELL, who would have thought of it but a woman? 1 went visiting the other afternoon. It was raining and my hostess had a sore foot. No one had thought to bring knitting. Do you know what we did? We got out her son's buzzer-practice set and sat there all afternoon and learnt the code. And we formed a little club and intend to practice every Tuesday afternoon until we are all able to copy twenty words a minute. Then we are going down and get first-class licenses. • » • T THINK it is just terrible! I refer to the way the average *■ radio salesman imposes on the average customer. I was listen- ing to a young man who thought he knew more than is good for him, talking to a poor little confused woman who had the perfectly good intention of buying her cousin a set for his Christmas. Something like this took place : "Well, madam, you see if your antenna hasn't sufficient length, you wilt have to add inductance into the primary circuit. Then again if — " and so on for about fifteen minutes until the poor thing was so confused that I interrupted and said : "Listen here, young man! You aren't talking to Professor Steinmetz. Tell this young woman just what she'll need in order to set up a simple set." He looked at me and blushed. Later, when in the subway to make a dinner engagement, I saw the same young man closely studying a book. It was a well-known volume on making radio simpler for the layman. • • * T RECENTLY bought a fairly large map of the United States. *■ in order to keep a record of broadcasting stations, but found that putting ink and pencil marks on it didn't improve its appearance any. So I went out and bought a number of large colored thumb-tacks and printed the call letters of the stations on them. Then I took a piece of string and pasted small pieces of paper on it to represent distance. When I hear a new" station, I apply another thumb-tack. I have a ready reference both as to stations received and the actual distance they are located from my town. • • • "C* RIEND HUSBAND and myself went visiting last week— * and we didn't enjoy ourselves one bit. Sonny had a nice radio set and there was a good program on ; but he kept switching around all the time to see if he "couldn't get it in louder." The result was that it sounded like a Chinese cabaret. • • • "^ISITED the editor 5>f Radio World last week to wish him ™ Merry Christmas. I never knew that one man could keep so busy. I remained in his sanctum about ten minutes and then just had to get out. He made me ashamed of myself for loafing. He blamed it all on National Radio Week. I believe him. I think that National Radio Week has done more to stimulate radio than any one thing that has happened since Marconi became a "bug." • • • EVER since amateur radio communication has been estab- lished between France and the United States, Friend Hus- band has seriously considered "scrapping" the set. He is wor- ried over the fact that the French stations might start broad- casting the latest fashions, and, he says, when they start doing so the American husband owning a radio set will be kept broke buying new clothes. How good of him to think of others! • • * HE was a neighbor of ours for about a week. Friend Hus- band met him on the train, and invited him to drop in and listen to a radio concert. During the intermission, like a lot of other "hams," I began to cut loose in all the latest radioese. I kept it up for about fifteen minutes — and all the time he was smiling sort of funny. Finally he and Friend Husband got to talking about business. F. H. confessed to being a lawyer, and then our guest sprung the surprise of my young life. "I'm consulting engineer for one of the largest radio com- panies in the country," he glibly uttered. Friend Husband is still alive. But he'll laugh himself sick if lie isn't careful. Radio Adds Joy to Her Home (C K»<U1 * Herbert) That radio U ftlUa* mm UBportaat ana* t b i b kxWhbty provad bp tfc. pfc-o«w*« Ml- D.fet»r mm, mi trmta ktr pat* "•»»- **• rmm* l**r po*"J far *• Th»

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16 RADIO WORLD News-Photos S . 1923 witt Captions By Patrick Nichols «J. Kadel & Herbert) (Above) Hug. inductance used at the College of the City of New York Radio Laboratories on the powerful transoceanic tran.mitter. ThU instrument "■■ specially bu It by the students of City College for the circuits used. The tickler may be seen Just inside the small coil. (Right) If you want to make your loud - speaker more powerful, try the stunt shown hers*. It is a well- known fact in scientific cir- cles that parabolic-shaped objects will throw sound waves, or heat- or light- waves better than conical- shaped objects. For that reason, all powerful search- lights have parabolic reflect- ors. This is Just what an object like the heater in the illustration will do if you place a loud-speaking horn before it. You will have to experiment as to the prop- er distance that the horn must be placed from the center, as the acoustic prop- erties of the objects sur- rounding It have a great ef- fect on it. This experiment has the same effect as if you lengthened the horn of the loud - speaker. If you don't happen to have a heat- er handy use a tin dishpan or a largo bowl, which la even better than the pan. (C. World Wide Photos) (Above) Step right up, L men! Absolutely the only No, we are not referring t the radio receiving set he scarf pin. C. Saunders, Bi claims to have Invented tl set. Here he is shown v tie. This is the result of is w| ( _ , (C. Kadel & Herbert) erwood) (Left) The world's smallest radiophone transmitting set —the smallest radiophone set in use. Despite its small size, it is said to be very efficient and is in use at station 9 CEX. It has a range of 75 miles. Note the small generator-set which is used to supply the necessary high voltage for the plate circuit. Two tubes are —one oscilator and o Digitized by (C. Kadel ft Herbert) (Above) Where research wo Rmgle is testing out a new I which allows the operator t Is in laboratories such ss tl Google

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RADIO WORLD low Radio Starting Plenty of Pep (G Kadel & Herbert) (Above) Not every dof In the world U privileged to hove hU Rolls-Royce end listen to radiophone music. But "Duke," prize Boston bull, being of the canine aristocracy, is not to be confounded with other dogs. In a special interview granted the photographer, this peer of dog- remarked that he would rather listen to KDK_A than gnaw juicy steak-bone. But, of course, all dogs are not so weJ "Duke," and their thoughts run to more mum • gnaw I , nl«. a fc tlttioB Th. ho| II educated „ A mit(t tadmr vitb whJcfc ^ mrnkk. th. ocwr.tor «o kr.P . ul watch heart ly crn frat ulatr d (or Thb oa th* being th« ftr»t g*t Into communication with Croat Britain and Franc*. » conducted In th. College oJ th. City of New York. Abraham ' of tranaatlantic receiver. Notice the miliammeter on the panel ""a mUCl1 e,,,T•,,, "* fnia* through tb. plate circuit. It "Mat of th. loading engineers are constantly conducting ■nonta to improve radio.

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18 RADIO WORLD With the DX Nite Owls A Canadian's Fine Work From Clifford Dafoe, 152 Patterson Avenue, Chatham, Ontario, Canaan I HAVE read in Radio World a number of letters from different owners of re- ceiving sets who claim to have "busted" a few records in receiving. If Mr. Weis is proud of his home-made set, I should be tickled pink with mine. I have a single-circuit regenerative set with one step of audio-amplification. Vario- coupler, 11-plate variable condenser, grid leak, and condenser, phone condenser, point switch, dials, and panel are all home-made. It isn't very elaborate or imposing in appearance, but it sure works! I am inclosing a list of long- range stations I made last night, just as I heard them. I had a friend with me, with another set of phones, so the list may be proved. I have a letter of verification from KHJ, Los Angeles, as I heard him first on November 13: KHJ, KGN, CJCG, CFCN, CKAC, CFCF, WNAC, WAAC, DN4. WHB, WDAF, WBT, PWX, WBAP, WFAA, WSB, also 6XB, and 6BT in San Francisco. These last two carry off the long-range championship for this locality. I have to share the honors with Mr. Collins, owner of the radio shop here, who, as well as myself, has heard all the above stations, using a Grebe CR 9. You United States boys have it all over us in Canada on the transmitting end, but we'll make>-you step to keep up with us on the receiving end. I never Jog a new station simply by the call letters, but wait until the name of the company or the town and State is given. I find this the only accurate way. The equipment of my set is as follows : English (Milliard) tube used as a de- tector, and Meyers R. A. C, No. 3, with Chelsea transformer as amplifier. I find either^ Brandes 2000-ohm or Sterling (English) 8000-ohm phones give almost equal results, though my faVorite is the Sterling set. My aerial is a single wire, 80 feet long, 13 feet high at one end and 16 feet high at the other end, where a 4-foot lead-in is connected which runs through a win- dow to my set. My ground lead is about 12 feet long and is attached to the water pipes. My set isn't a freak in any way. I use a standard hook-up and have built one for my sister and one for a friend. The three sets work just about the same. The secret is in the value of the grid leak and grid condenser, also the phone con- denser. I don't know what value they are as I just experimented till they worked right. I wish to thank W. W. J. for the help he unknowingly gave me in adjusting my set. Hoping this may find space in our paper, paper. » » » Aerial 200 Feet Long From M. P. Bailey, Moscow, Idaho I NOTICE a letter in Radio World No. 35, dated November 25, from Kenneth F. Smith, Birmingham, Alabama, regard- ing the number of stations he has been able to hear and which he claims is a record. I believe that I have him beaten, but do not consider that I have made a record as yet. Not counting our local broadcasting station, the nearest station that I have picked up is at Portland, Oregon, about 400 miles away, while the farthest station af RADIO WOULD was to waive afcetatoi at toek-ane af tto Tartans "DX Nlafct OwV with a vfcwr af heard is Atlanta, Georgia, about 2,000 miles. However, I counted the stations on my log about two weeks ago, and had 59. Since that time, I have picked up several more. My long-distance ones in- clude WOC, Davenport, Iowa; WHB, Kansas City, Missouri; KSD, St. Louis; Dallas, Texas; Fort Worth, Texas; Win- nepeg, Manitoba; Minneapolis; Louisville, Kentucky. My set is a home-made single circuit with two stages of audio and no radio amplification. I have a single-wire aerial about 200 feet long and use a water pipe as a ground. The aerial is about 20 feet high. I do not count any station that I cannot understand through the Mag- navox. I have on file replies from most of the stations heard, as I usually write> them of the reception. I was able to pick up St. Louis several nights ago broadcasting a dance program from the Hotel Statler. They were so loud that we could have danced by it. This is about 1,500 miles. * » * Responds to the Hooting From Norman Peterson, Concord, Contra Costa County, California HEARING the Hoot! Hoot! of the night owls, I respectfully submit what I think is a record. "Maybe they are and maybe they aittt!" Here we go: WHB, Kansas City, Missouri, 1,300 miles; WBAP, Fort Worth, Texas, 1,400 miles; CFCN, Calgary, _ Canada, 1,400 miles. Detector tube, vario-coupler, vari- able condenser — that's all! * * a With Detector Tube Only From Perkins Bennef an, (37 Poplar Avenue, Fresno, California SINCE everybody else seems" to be do- ing it, I have decided to tell my re- ceiving record. I have heard about 70 different stations, and usually get about A Real Nite Howl! Ripley in "The Globe,'' New York 20 each night. My best record for 4 hours is 21 stations; 5 hours, 23; 6 hours, 26. The stations I get clearly and loud each evening range from KHJ, KFI and KWH, Los Angeles; KDPT, San Diego; KFAF, KLZ, DD5, DN4, Denver; KZH, KDYL, Solt Lake; KFC, Seattle; KGG, KGW, KYG, Portland, to KUO, KFDB, KDN, San Francisco. For my DX work: WOC, Davenport, Iowa, 1,600 miles; PWX, Havana, 2,500 miles; KSD, St. Louis, 1,600 miles; WDAP and KYW, Chicago, 1,800 miles; WSB, Atlanta, Georgia, 2,000 miles. That's a pretty good record for one night's work! On December 2, I heard all the above stations. I don't have such luck every evening, but nights similar to that are not so rare. I won't say that these stations came in loud enough to be heard all over the house; but they do come in fairly loud. PWX came in very QSA. My set consists of a detector tube only. I use a vario-coupler and variable con- denser for tuning. My aerial is about 40 feet high. * a * Accepts Mr. Smith's Challenge From Jack Cowan, 512 Cotton Avenue, Weat End, Birmingham, Alabama T N Radio World, No. 35, dated November *• 25 is a letter from Kenneth T. Smith. It so happens that we are located in the same city but so far have not had the pleasure of meeting. However, I accept his challenge, so here goes to "get my feet wet." I have a home-made set, also, with two stages of audio-frequency, aerial 125 feet long, 35 feet high. On Saturday night, November 25, the following stations were brought in clearly over my loud-speaker, which, by the way, is only a 6000-ohm phone and an ordinary Grafonola horn: WCR, Buffalo; WBAD, Minneapolis; WDAP, Chicago ; WNAD, Norman, Okla- homa; WEAP, Fort Dodge, Iowa; KHJ, Los Angeles ; 8XAK, Springfield, Ohio ; WSB, Atlanta; WOM, Atlanta; WOC, Davenport, Iowa; WBAP, Fort Worth; WKM, Memphis; KSB, St. Louis; WDAF, Kansas City, Missouri; WHAS, Louisville ; WFAA, Dallas. On other nights, I have heard up to eighteen stations. I make no record of stations received in my log unless they are audible enough to be heard over my loud-speaker. Within the last sixty days, I have heard sixty different stations, all of which are located over 250 miles from Birmingham, Los Angeles being the great- est distance. * * ♦ In One Year ! From Joseph Muntyan, 24s East Nth Street. New York City, N. Y. I NOTICED an article in one of fhe sapers the other day entitled, "Does It Pay to Assemble Your Own Set?" My answer "is, "Yes!" I knew rtothing about radio until about a year ago. I bought parts of a crystal set and assem- bled it myself, getting as good results as may be expected from a crystal. But the results did not satisfy my wishes. Later I bought a blue print of a "long and short- wave honeycomb coil set with 2-step am- plifier." I completed \Jne set about three months ago. It took "me two weeks to assemble the set as I took my time with it, making sure that all connections were made right and properly soldered. I have two cabinets, one for the receiver and the other for the 2-step amplifier. For Digitized by Google

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RADIO WORLD 1' With the DX Nite Owls (Continued from preceding page) loud-speaker, I am using a single Bald- win phone, type C, which brings in the music of the nearby stations clear and loud enough to dance by. Furthermore, it is a pleasure to tune in and out the different stations on this set, as I do not experience the hissing and buzzing sounds that so many complain of when they put their hands close to the set. In appear- ance and operation this set is as good if not- better than some of the higher-priced sets on the market to-day. Following is a list of radiophone stations I have re- ceived to date with a wire connected to the fire escape as aerial. The landlord would not permit me to put an aerial on the roof: WJZ, WHN, WWZ, WOR, WAAM, WEAF, WOO, WBS, WGY, WHAS, VVOZ, WRW, WOE, WHAZ, WWJ, WOC, KDKA, WIP, WFI, WBZ, WVP, WBAN, WNAC, WGI, KYW, WDAP, WHB, WJAX, WAAC, WMAK, WGR, WSB, WDAF, WBAP, KSD, WMAS, WQAA and IXD. I have letters and post cards from most of the stations confirming my statements; and, furthermore, I keep a record of the time and date that I receive the stations. All the above-named stations were re- ceived by using 2 D-L 50 and 1 D-L 75 coils, including station WVP. I would like to know what results I would get by using an aerial 150 to 200 feet long. This is another instance where it is not necessary to have an aerial in order to do good work. It is quite possible that if the writer were to put up an aerial such as he suggests in his letter, his results would be improved. Landlords must be landlords, and, evidently.^ the poor radio amateur is never appreciated until it is too late. — The Editors. * * * Heard in New Brunswick From Hollts Baird, River de Chute, Carleton County, New Brunnrick I HAVE noticed letters in Radio World regarding receiving records. With Gib- lin-Remler coils in a standard tickler-cir- cuit using radiotron tubes, mica variable condensers and only one step of audio with 22'A volts plate-voltage I get the following stations: WJZ. WGY. WWJ, KDKA, WBZ. WEAF. WBAY, WNAC, NOF, WHAZ, 'WOR, WIP, WGL, WLW, WAAN, Columbia, Mississippi; WOO, CKAC, Montreal; WFI, WGI, WHK, KSD, WDAP, CFCA, Toronto. These stations are from 475 to_ 1,400 miles from here, with the exception of CKAC, which is only 275. The majority of them are heard regularly. Of course there are better records than mine; but I think it is better than Mr. Merklein's. * * • Mr. Miller Adds to His Set From W. MUler, Box Z2Z, Southern Methodist University, Dallas, Texas LAST night (December 13) being a quiet night for Dallas, I was afforded the opportunity to do a little stepping with my one-tube contraption. At vari- ous intervals between the hours of 6 o'clock and 11 o'clock I received stations WPA, WWJ, WOAI, WDAF, WGM, WOC, WBAP, WHB, WOS, KSD, WNAV, KFAF, PWX, KDKA, WGY, KLZ, WCX, KLN, WSB, KZN, KHJ, WDAJ, WLAC, KDPT and enjoyed opera from KYW. I submit this information as one night's results — not claiming a record. This per- formance should prove satisfactory to any "night owl." My circuit is as set forth in Radio,. World. No. 30, dated October 21, with several improvements. Since adding these improvements, I have added six morj States to my log, which now totals 33, besides Havana, Cuba; _ Tampico, Mexico; and several Canadian stations. Not so bad for a novice! » * » Without Any Grid Leak A Suggestion to Increase the Range of Mr. W. MUler'. Circuit REGARDING the hook-up of Mr. W. Miller, published in Radio World, No. 30, dated October 21, which has at- tracted unusual attention among ama- teurs throughout the United States and Canada, Radio World has received the fol- lowing interesting suggestion from Dr. Willis L. Hale, 47 North Washington Street, North Attleboro Massachusetts. Dr. Hale writes: "Increase value of Miller circuit 100 per cent by leaving out all grid leak and use a vernier rheostat. It's a dandy 1 Good»for 1,000 miles any night." Transatlantic Tests Successful France Copies Signals of American Ama- teurs for First Time, December 13 FIRST reports on the transatlantic tests of the American Radio Relay League, received at the league headquarters, Hart- ford, Connecticut, on Wednesday, December 13, show that twenty-five American amateurs were heard in England and thirteen in France. For the first time in the history of amateur radio the French were successful in copying the signals from American amateurs. December 12 marked the start of the tests, and they will continue until December 31. The following were heard in England: 1-BGF, Perry O. Briggs, 52 Girard ave- nue, Hartford; 1-YK, Polytechnic Institute, Worcester, Mass.; 2-( K, A. G. Kasten- mayer, Schenectady, N. Y.; 2-NZ, E. R. Ragusc, Tottenville, N. Y.; 2-XAP, Rensselaer Polytechnic Institute, Troy, N. Y.; 2-ZK, George C. Cannon, New Rochelle, N. Y; 2-ZL, J. O. Smith, Valley Stream, L. I.; 3-ZW,' Walter A. Parks, Washington, D. C. ; 8-AQO, C. P. Meredith, Cazenovia, N. Y.; 8-AWP, S. Woolworth, Syracuse, N. Y.; 2-EL, H. H. Carman, Freeport, N. Y.; 2-BML, H. H. Beverage, Riverhead, L. I.; 2-LY, C. A. Wood, Port Richmond, N. Y.; 3-BGT, C. S. Risley, Atlantic City, N. J. ; 3-IIC, G. L. Diechman, Baltimore, Md.; 3-ZY, L. A. Dunham, Washington, D. C; 4-FB, A. Bush, St Athens, Ga. ; 4-PI, L. Rexach, San Juan, Porto Rico; 7-PO, G. E. Kensey, Seattle, Wash.; 8-GQ, R. Moore, Columbus, Ohio; 2- ZS, C. R. Runyon, Jr., Yonkers, N. Y.; 3- XD, University of Princeton, Princeton, N. J.; 4-BX, G. S. Smith, Wilmington, Del. The following stations were heard in France: 8-AQO, C. B. Meredith, Caze- novia, N. Y.; 1-YK Worcester Polytechnic Institute, Worcester, Mass.; 1-BGF, P. O. Briggs. Hartford; 1-BCG, Minton Cronk- hite, Greenwich; 2-XAP, Rensselaer Poly- technic Institute, Troy, N. Y. ; 2-ZK George C. Cannon, New Rochelle, N. Y; 3-HG, G. K. Deichman, Baltimore, and others. To make your receiving set really complete, equip it with a Magnavox Radio — the Repro- ducer Supreme. The electrodynamic principle involved in its construction makes the Magnavox Radio a most efficient converter of elec- trical energy into sound waves. With either size Magnavox Radio the hook-up is as simple as connecting the ^rdinary head receivers. R-2 Magnavox Radio with 18-inch horn : this instru- ment is intended for those who wish the utmost in amplifying power; for large audiences, dance halls, etc $85.00 R-3 Magnavox Radio with 14- inch horn : the ideal instru- ment for use in homes, of- fices, amateur stations, etc $45.00 Model C Magnavox Power Amplifier insures getting the largest possible power input for your Magnavox Radio. 2 Stage AC-2-C . $80.00 3 Stage AC-3-C . 110.00 When you purchase a Mag- navox product you possess an instrument of the highest quality and service. Magnavox products can be had of good dealers everywhere. W rite us for copy of new illustrated booklet. THE MAGNAVOX CO. Oakland, California N. Y. Office : 370 Seventh Ave. Mmwox D/ie Reproducer Supreme Digitized by Google

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20 RADIO WORLD Lee de Forest Discovers New Oscillion No. 1,07,«M. Patentee: Lae de FaMt, Now York City. N. Y. THE latest radio invention of Dr. Lee de Forest appears to have a number of advantages over the present types of oscillions. Told in his own words, Dr. de Forest says: "I provide a glass vessel containing the nsual three electrodes, the filament, or glower; the grid; and the plate, or wing — the vessel being designated generally by reference numeral 1. The vessel 1 is preferably tubular in form ond con- stricted at one end to form a neck 2. In Figure 1 the neck 2 is open, as indi- cated. The plate or wing element 3 is preferably in the form of a cylinder, and is positioned close to the wall of the ves- sel, or, preferably, plated directly on the wall of the vessel, and may be of. any desired suitable material such as silver, platinum, tungsten or the like. Fitting in close contact with the plate is a band of tungsten, or nickel, or the like, indi- cated at 4, to which is connected a lead wire 5, sealed through the wall of the vessel as shown. The filament or glower electrode 6, which is preferably carbon, tungsten, or oxide-coated platinum, is as shown, in the form of a loop or "hair- pin," anchored at its lower end in a glass frame 7. The glass frame 7 is in the form of a glass rod which rests at its lower end against the bottom of the ves- sel. Intermediate its ends, the frame is formed with yoke arms which form a space between them, in which space the * • New Electron Tube No. MS7.W7. Patented Deceashar S, ISO. Pat- antaa: Eu»ene L. Moallar, Chicago MR. MUELLER'S invention relates to electron tubes and, more espe- cially, to electron tubes where in the source of electrons comprises an arc. Electron tubes are of general use as sources of high-frequency current, de- Four ftffurea, show! menu of const. "wmntically the ele- Mueller't new Four figures, ihowing cUagramaticaJlr tha moat Important part* of Dr. deForoat'a Invention. filament 6 extends. Above the yoke por- tion of the glass frame or rod the rod is hollow, and the respective leads 8, 9, of the filament extend upwardly in the hol- low rod and are sealed through the wall." * tectors of radio-frequent oscillations, and, also, as amplifiers of feeble currents. These electron tubes comprise an evacuated bulb containing a source of electrons, a metal "plate member and a "grid" member consisting of fine wire or a perforated metal sheet interposed between the source of electrons and the "plate" member. In the arts of space telegraphy, teleph- ony and the like, the electron tube finds great application; but the particular method emplnverl to rnahl* fhe tube to function properly on one of its several uses is not a part of this invention. The specific requirements of the use to which the tube is put will necessitate adaption of the tube to meet these requirements. However, such adaption is only for the purpose of obtaining a certain capacity or obtaining some result which does not alter the fundamental characteristics of the tube. To cause the tube to function in any of its capacities as a detector, high- frequency current generator, or as an amplifier, it is only necessary to properly place it in the circuit of which it is to be a part. The tube must have suitable coacting elements in the circuit. This fact is well known to experts. The objects of this invention are as follows: To provide an electron tube having an arc for a "source of electrons, this arc being confined in a tube con- taining a vaporizable material; to provide an electron tube capable of sustained and prolonged usage. In continuous-wave telephone work, the filament of the os- cillator and modulator is subject to a great strain from the high voltage and amperage of the grid and plate circuits so that the life of the tube is very short. In Mr. Mueller's device, the filament is done away with, thus increasing the life of the tube. New System Applied to Coupling Apparatus No. 1,417,772. Patented December 5, ISO. Pat- antaei John B. Nowian, Dearer, Colorado THE object of my invention," says Mr. Nowlan, in his transcript, "is to pro- vide a radio-receiving apparatus of high selectivity whereby signals transmitted on adjacent wave lengths may be received and isolated for reproduction without un- due interference. Another object is to provide a circuit arrangement in a radio- receiving apparatus for securing extreme accuracy in the coupling of the tuned circuits of the receiving apparatus; also to provide a construction of coupler for securing accurate adjustment of coupling of the tuned circuits _ of the _ receiving apparatus; and to provide circuit connec- tions and an arrangement of parts where- as Combination of a primary circuit mclodmg a primary winding, and a secondary circuit com- prising a pair of windings, each directly con- nected in series and each cumulatively counted to the primary winding, tha secondary drccdt ba> gmning at one and of tha windings and con- tinuing m a single direction through nth or sec- ondary winding to tha end. These the sola terminals of the with the by simplicity in adjustment, compact- ness and selectivity in the different parts of the receiver circuits is secured, with means on a receiver panel whereby the apparatus may be protected against heavy surges and electrostatic charges, and may also be protected when not in use by direct connection of the antenna with ground." The radio-receiving apparatus of this invention comprises an insulated panel carrying the radio equipment supported on the rear thereof and housed within a cabinet. The apparatus includes a radio- frequency oscillating circuit which may be an antenna ground-circuit, a coil-col- lector circuit, or a ground system bal- anced against a free ended extended con- ductor. The oscillation circuit includes a primary inductance tapped at selected points to switch contacts whereby the desired amount of inductance may be in- cluded in the oscillating circuit. » * » Coming Events Tha editors of RADIO WORLD w«l -<~n. nubllah aewa Items of all coal shows sad exsoeUlaaa. fall SECOND NATIONAL RADIO EXPOSITION, direction International Trads Exposition Co. Chirsgo, January 13 to 30, inclasire. 1923, George ^r«"'d^cs^o0rra pnbIicit7' 40 Sootfc dearborn PERMANENT RADIO FAIR FOR BUYERS. Hotel Imperial, New York City. Open from September, 1922, to Hay, 1923. AMERICAN RADIO EXPOSITION, Grand Csa- tral Palace, New York Oty, December 23 to 31. Colwell * Korbell. Iluildi.,. New York City, director! of — SECOND DISTRICT RADIO CONVENTION. Hotel Penneylranis, New Yark Oty. March L 2, and 3, 1923. FIRST UNIVERSAL EXPOSITION OF Df. VENTIONS AND PATENTS, Grand Central Pal- ace. New York City, F.brs.ry 17 to St, J5m^n, 1923.

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RADIO WORLD NAA to Be Chief Government Broadcaster Takes Place of NOF, Which Will Resume Its Experimental Work f^AA, the great Naval Radio Station A-^l at Radio, Virginia, near Arlington, D. C, becomes the United States Gov- ernment's chief broadcasting station for official information on January 3, 1923. On that date, all regular broadcasting previously handled by NOF, the radio experimental station of the Navy at Ana- costia, will be transferred. Thereafter, NOF will resume its experimental and research work, which may include the broadcasting of the Navy and Marine Band music in the interest of modulation teats. A special wave length of 710 meters from the Government and public broad- casting band was assigned to NAA by Herbert Hoover, Secretary of Commerce, on December 15, at the request of the Interdepartmental Radio Committee. This was done in order that the several regular circuits of the Army and Navy located there may be operated simul- taneously without interference which occurred when phone broadcasting was undertaken on the lower governmental wave lengths from the main antenna. The new radiophone transmitting set was especially made for NAA at the Naval Radio Laboratory at Anacostia. It is based on the master-oscillator, power-amplifier system, and employs six 250- watt tubes, giving an output of 1J4 kilowatts. The apparatus is arranged so that the waves from 400 to 2,200 meters may be nsed in transmitting, and the power is derived from a 2-kiIowatt gen- erator. When transmitting on 710 me- ters, a special single-wire antenna, stretched from the top of one of the 400-foot towers, is used. This new cir- cuit does not interfere with any of the other circuits, although used simultane- ously. The height of the antenna gives practically the same efficiency as the multi- ple-tuned antenna used at Anacostia. When transmitting on the high-wave length, 2500 Six New Broadcasters LICENSES issued to broadcasting sta- tions on 360 meters during the week ending December 16 include the follow- ing: WQAL— Cole County Tel. and Tel. Co., Mattoon, 111. WPAK— North Dakota Agricultural College, Fargo, N. D. WPAT— St Patrick's Cathedral, El Paso, Tex. WPAH — Wisconsin Department of Markets, Waupoca, Wis. WOAY— John W. Wilder, Birming- ham, Ala. KFDH — University of Arizona, Tucson, Ariz. Radio Entertainment for Hire ANEW phase of the radio game is that of entertainment service fur- nished on call, just like an orchestra service. If you wish radio entertainment, a Washington radio concern announces that it will bring a set, install it and guarantee entertainment from the ether suitable for a social evening, "or no charge." Subscribe direct or through yosxr Mwt dealer. |&00 a year, $3.00 sis months, $150 three months. Ratfio World, 1483 Broadway, N. Y. C meters, the large antenna will be used and other circuits will be interrupted temporarily. The design of this special set will permit of excellent modulation for the sending of speech and even music. Naval radio en- gineers say. Transmitting ranges will vary with the season and with the day and night; but it is expected that a range of several thousand miles may be attained in night- time transmission during the winter months, although this may fall off in day- time sending during the summer months to a 250-mile radius. Recent broadcasts of the President's congressional address are reported to have been heard as far west as Chicago and Detroit, which speaks well for the work of NOF on 427 meters. Basically, the new set for Arlington is built on the results of radiotelephone broadcasting experiments conducted from Anacostia and a knowledge gained from the opera- tion of the well-known set at NOF. The Latmat and Moat E—ontial Fart of an Efficient Tuba Sat ISM tanas! Clarinet fcunait. Um Fllumt Correal: m Battary Life; EllaUeetM Hiwlea Variable Grid Leak Condenser Con Prlca only $1.00 Ml. Vernon. N. T. Dm. ». lilt Co.. Int. Sr. Tort do. Dear Htn : M> Variable Ortd i toe which I wtah to ta all ran skla fat IL Would not aril tkla Variable far SIS at 1 eeale wether, loan trob, I) C B. TATLOB. H. T.. *». H. m H. B. ML V?"** at rat (Mr* and row wll be Mi •* mm lCtj5r"a Chas. Freshman Co., Inc. 91 Beelcma. St, rWw York Otj Home of THE RADIO DESK A NEAT AND CON- VENIENT DESK FOR YOUR RECEIVING SET sting board for switch** i a has a closed with for batteries, rectiBar, et*. A flat inf. The front half of top Is hinged aad has a large compartment apderaaath fot head phones, tester, pragnsantea, ate. It is all dosed, yet easily accessible. No doors or drawers in the way ami enoagb room to sit up comfortably aad operate. Site of top 23x36 In. Height 91 in. M ade of Birch la Wahtat or Mahogany rubbed finish at 118.00. Or of solid Oak In Golden or Silver Gray flaiab at SIMM each. shipped direct from the factory anon i ' ceipt of price. Specify freight or express. Proposition ' dealers. MADE BY WM. HUES & SON, Huntingburg, Ind. Maaafaetarera of Tefephoae CaMaets alaea INt Wkat Shall I Give HER For a Present? The eitoemt treat amm ■toot particular stent her Lea Senile Skin Pood L - Are - Ba - del ideal Mme. Anita K&nti's Christmas Beauty Box Mme. KaatJ'a wonderM arafjaratioae Wt« baas the taTOrite far Tear* aad need wf that fcateeae beaatiea of both Paria aad New York. Among Mate. Kaatl'a penoaal caenta caa ha named the retrain* eta re aad acuta eta re. ABWlJim SATISFACTION GUABANTKSD '= $10 MME. ANITA KAMI Any individual article in tkie e—ortmrnt #n» TW04ft Of 4$\ plot*.

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 New Wonders of Radio Seen at Big New York Exposition THE American Radio Exposition, at the Grand Central Palace, New York City, opened at 2.15 p. m., on Thursday, December 21, and closed at midnight, December 30, 1922. It was, un- doubtedly, the most successful radio ex- hibition to date, and will become an an- nual event. United States Senator-elect Royal S. Copeland made the opening address. His subject was, "Radio as It Concerns Every- day Folk." He was followed by Colonel A. H. Gns- wold of the American Tel. and Tel. Com- pany, who spoke on "Radio Broadcast- ing." The famous screen actor, Rudolph Valentino, gave a snappy talk on "The Truth About Myself." All of these and other speeches were successfully broadcast. All addresses and songs were broadcast from WEAF through speech amplifiers which were located on a truck in the middle of the exposition floor. Through the agency of these amplifiers, it was possible to hear all speakers clearly. The loud-speakers made it possible to hear everywhere in the large exposition grounds. . . Some striking features of the exposition were : A regenerative set so large that an or- dinary-sized man must stand on a step- ladder to work it. The controls had to ' be grasped with both hands. A set made of imitation ivory (ivory pyralin) with solid gold controls. This set was designed for use in a Fifth Avenue boudoir. Major Edwin H. Armstrong working his famous superheterodyne circuit. In order to do this he worked in a large glass-cage to cut capacity effects. Following is a complete list of the ex- hibitors : Eiseman Magneto Company. Western Electric Co. . Associated Manufacturers of Electrical Supplies. Coto Coil Company. National Airphone Corporation. The Bristol Company. C Brandes, Incorporated. Dubilier Condenser Radio Company. Signal Electric Manufacturing Company. "The Evening Mail," New York. Tewett Manufacturing Company. Pathe Phonograph & Radio Company. Radio Detector Company. Electric Storage Battery Company. Experimenter Publishing Company. Radio Directory & Publishing Company. Gould Storage Battery Company. Milliken Brothers. Allen D. Cardwell Mfg. Corporation. DeForrest Radio Tel. & Tel. Company. Radio Corporation of America. National Carbon Company. Marko Storage Battery Company. Weston Electrical Instrument Company. Pacent Electric Company. A. H. Grebe & Company. American Radio tic Research Corporation. National Radio Products Company. H. Hyman Company. Radio Call Book. Formica Insulate Co. Hutchinson Radio Co, Executive Radio Council (2nd District). American Radio Relay League. Norman W. Henley Publishing Company. S. Newman & Company. Crocker- Wheeler Company. Alden-Napier Company. Experimenters Information Service. Electric Specialty Company. . Stanley & Patterson. Williard Storage Battery. Inter-Ocean Radio Corporation. ; Fiber Products Company. 'The Radio Guild Office of American Radio Exposition Company. General Insulate Company. Davis Manufacturing Company. Amateur Home Made Set Contest. Triangle Phone Parts. Sleeper Radio Corporation. C. D. Tuska Company. Copper Clad Steel Company. Stromberg-Carlson Telephone Mfg. Company. American Bell Radio Company. Engravers & Printers Machinery Company. Rasla Sales Corporation. Malone-Lemmon Laboratories. National Radio Chamber of Commerce. Moon Radio Corporation. Manufacturers Patent Company. Novo Manufacturing Company. Feri Radio Company. Tait Knob & Dial Company. Bel-Canto Corporation. "Radio Digest." Clapp-Eastham Company. Crosley Mfg. Company. Radio Mica Products Company. "Popular Radio." HolmH-Cabot Company. Betfs & Betts Corporation. Scholes Radio & Mfg. Corporation. Le Fax Corporation, Incorporated. Radio Detector Company. States Radio & Engineering Company. Brilliantone Radio Company. The Radiall Company. Ackerman Bros. Company. Incorporated. Electrical Record. Post Electric Company. Boissonault Company. Radio Industries Company. Burgess Battery Company. Next week'* issue of Radio World (published January 3, 1923, dated Jan- uary 6, 1923) will contain a special arti- cle, fuKy illustrated, describing the Ameri- can Radio Exposition now at the Grand Central Palace, New York City. A New Adapter Manufactured by Industrial Sales & Engineering Co., Newark, N. J. •yHE Radiphono Adapter A manufactured by In- dustrial Sales Engineering Co., Newark, N. J., is a device that may be ap- plied to phonographs in reproducing radiotelephony clearly. It is of nonreso- nant material, and when used with a fairly sensi- tive phone and at least one stage of amplification produces results. It fits on the tone arm of an ordinary phonograph. Due to the fact that it is made of heavy insulating compound instead of metal, there is an absence of vibration. In view of the fact that it sells for a reasonable price, it should prove attractive to all amateurs who seek clear reception. New Firms and Corpora- tions (The Srms and corporation* mentioned in these columns con be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Kendall Electric Co., SU West 7th St., Des Moines, Iowa. Wayne Radio Co., 1204 Calhoun St., Fort Wayne, Ind. Altex Electrical Supply Co., Brooklyn, $10,000; B. Levy, F. Alexander, H. J. Sanders. (Attorney, N. B. Finkelstein, 51 Chambers St., New York.). Lake Crystal Electric Co., Lake Crystal, Min- nesota. The Electric Shop, North Kansas Ave., Marce- lina, Mo. S. O. S. Radio Corporation, Rochester, N. Y. Globe Electric Co., 226 East Long St., Columbus, O. Sterling Electric Service & Supply Co., Albany, contractors, builders, $20,000; A. I. M. and A. Weintraub, F. Berner. (Attorney, N. M. Medwin, Albany, N. Y.). Jack Sign Co., Wilmington, Del., electrical signs, $20,000. (Corporation Service Co.). Mogul Electric Co., Manhattan, radio instru- ments, etc., $5,000; J. P. Mirandy, S. M. Knapp, Z. Wilder. (Attorneys, Reit & Kaminsky, 305 Broad- way, New York.). Keystone Electric Co., 24 Public Square, Wilkes - Barre, Pa. CAPITAL INCREASE Moloney Electric Co., Manhattan, $700,000 to $1,500,000. Heard at Radio Counter A Conversation Between Customer and Radio Clerk (Part VIII) KT RECENTLY heard it said that if I connect a variometer in my plate circuit, I would convert my loose-coupler set Into a regenerative set, or that I could get my circuit to oscillate." "That is absolutely right. By doing so, you will also increase the loudness of your signals.'* "Does it matter Just what kind of a variometer I use?" "No; any variometer will function. But, of course, as with anything else, it always pays to get the best." "Well, that may be true; but I wasn't going to spend any more money in an initial Investment, than necessary. This Is merely an experiment on my part. If it works satisfactorily, I intend to purchase the best set on the market." "That is sensible; but, then, I am under die impression that a cheap one might not function as well in the beginning as a good one. You would then lay the blame on the circuit, forgetting that probably the instrument was the cause of the trouble." "That is very true. What do you consider the best?" "Well, I think that this one, right here. Is the best on the market. Of course, it is slightly more expensive than the one next to it; but it Is well constructed and win stand up better." "All right, I shall purchase that one on your recommendation. Please have it wrapped up." "Correct, sir. Just one moment— and I will have your change." (To be continued) Mas'er Baldwin Phones Reduced! Singles tt.Bt Headset S12.M Clarophone S2S.se Dealers write. We carry site ElHmasn Magnet* Corp. products. CLARK & TILSON I EAST 42nd STREET NEW YORK Digitized by Google

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RADIO WORLD 23 Radio Books Reviewed "Radio for All." By H. Cernaback, editor, "Radio Now.." Published by J. B. Lip- pincott Co, Philadelphia. $2. WHAT the novice in radio needs is a book' in which he can get all the information necessary to understand radiotelephony and radiotelegraphy, to make or buy a receiving set suitable to his means, to know how to operate his set, and, after he has an understanding of the radio art, information that will en- able him to advance and get the most out of his outfit. All this must ordinarily be dug out of text-books, pamphlets and government publications, but the aim of "Radio for All," by H. Gernsback, is to have all the data and information that the beginner will need from the time that he takes up radio. It is a permanent, com- prehensive reference book for the dyed- in-the-wool amateur. The chief features of the book are: What radio is. What instruments to use and how to operate them, shown by draw- ing diagrams. How to read diagrams. How to make receiving instruments. Miscellaneous radio information, with lists of all broadcasting stations in the United States and Canada, and the Radio Act of 1912. • Map of the United States Radio- phone Broadcasting stations suitable for hanging in radio room. Other features are : The theory of radio carefully explained with drawings. De- scription of and instruction for operating instruments of receiving and sending sets, with all picture diagrams of the wiring of the apparatus. How to make your own receiving sets costing from $3 to $50. How to read diagrams. For every dia- gram there is a corresponding technical diagram using symbols instead of draw- ings. How to tune sharply and elimi- nate interference from other stations. How to protect your set from lightning. Explanation of time and weather signals. How to make a practical vacuum-tube detector, two-stage amplifier set costing less than $50. How the radio compass works. Underground aerials, loop aerials, and directional aerials. Formulae for finding wave length; miscellaneous form- ulae for finding capacity of condenser and other instruments. Tables of wire resist- ances, wave lengths and their correspond- ing frequencies and approximate wave lengths for different aerials. * * * Tho Radio Constructor." By S. Newman. IT is a fact that a great deal of money may be saved by making one's own set. Also, the fun to be had in building radio apparatus is not to be overlooked, as it is with pride that one looks at the thing he has produced himself. Unfor- tunately, a great number of fans have not as yet learned to read with ease dia- grams in which symbols are used to rep- resent each piece of apparatus. So far, we have seen only a few really practical plans for building apparatus with stand- ard parts, but we have noticed recently the tendency toward simplifying the dia- grams in order to bring them, so to speak, within reach of the layman. Among the practical plans _ which we have seen lately may be mentioned those published by S. Newman & Co., 74 Dey Street, New York. This firm also pub- lishes a small booklet containing data for the construction of receivers and ampli- fiers of various types, presented so as to appear as if seen from above. All con- nections are shown as clearly as possible, and enable even an inexperienced person to attach the wires between the proper binding posts on each apparatus constitut- ing the set. In the plans, which are of large size, a perspective view of the completed outfit is given, showing how the unit looks when completed. Among these plans are some giving directions for_ the construction of regenerative receiver, radio-frequency, amplifiers and other ap- paratus. "The Radio Constructor" is published In a compact size and is profusely illustrated with hook-ups. * * * "Ideas for Radio Experimenter'* Library." By M. B. Sleeper. Published by Nor- man W. Henley Publishing Co* New York. V/f R. SLEEPER'S new volume con- tains valuable information for the advanced radioist who wishes a wealth of data and information that will help him build better and more efficient radio re- ceivers. This is a "how-to-do-it and a how-to-make-it" book from cover to cover. A great deal of information ana facts are given on the construction of inductance coils for various wave lengths. Tables are included which make the wind- ing of coils for any particular purpose easy for the novice. The construction of various testing and laboratory instruments is also included. A chapter is devoted to the various methods of hooking up tickler coils. This will be of value to the radio workers who anticipate the best re- sults with their home-made regenerative outfits. Overheard in the Subway "FIRST FLAPPER— "Oh, yes; I find •*• that by shunting a double-o-five con- denser across the primary of my first amplifying transformer I don't get thaj howl. Why don't you try it?" FLAP No. 2— "I will, later. I am experi- menting with resistance coupling just now, and I am getting some good results out of it." FIRST FLAP.— "Well, good luck O. W. Seventy-three, C. U. L., this is my station." * * * Old Lady to Radio Operator— "And where is that station STATIC that I hear my grandson talking about?" * * * Man listening in for . the first time — "I didn't know that the zoo had a station." Operator— "ZOO— how come?" M. 1. i. f. f. t. — "Sure — don't you hear the birds singing I" Operator — "Ooooooooooooooooh 1 1" $2.95 VARIOMETERS VARIO-COUPLERS The** Instrument", completely assembled and guar- anteed, are perfect in construction and design. All part* are accurate. Easily ateunted en panel. Coupler primary hat seven taps. 3/16" or \LM ahaft. Cflaetfva tuning range (BO to 600 meter*. WILEY VARIOMETER COMPANY 2323 8«. Central Pk. Av. CHICAGO. ILL. VARIABLE CONDENSER 33 plate Variable Con- densers. Gennine brown Bakelite ends. Heavy Aluminum Plates. All bras* parts nickel plat- ed. Complete with Knob Dial and Pointer, 91.75 Cash with order. E. J. ROBE 620 W. Monroe St. CHICAGO, ILL SAVE MONEY ON HIGH GRADE Variable Condensers Direct from Manufacturer* Take tbs middleman'* profit and wil- ing eoets tor yourself. We aell you di- rect. Theae extremely accurate lnstru- menta made by experienced condenser people are minus the decorative frills that add to coat. Price reduced to rook bottom without sacrificing quality In the least. Satisfaction or your money keek. Write today for very Interesting cir- cular. nicafli ti : 12.95 Tsar Order ruled by dsnar to a day sr am. MANUFACTURERS' RADIO ASSOCIATION St. Newark, H. 9. CjataQifo REAL CABINET LOUD SPEAKER NOT JUST THE USUAL HORN ENCLOSED IN A CABINET L±M Bcauliful-Compacl-TONE COMPARABLE ONLY TO THE %tfr FINEST CABINET PHONOGRAPHS Nstalas ess* te ant* te mryWtfy'l m forwent ef a ree-itaet Mat a slab-ares* less Meeker. We snke a ernslek) Use— ef tee Mesaet den wertnwtlie tsresse* •ot wit* free a,,,, nibbed Salens, ir I SOLAS ere sIwim nM seder nessy kask teeraetoe^te easel Is «ela*» sac far earssn Is keaaty sad test say a* *> re be IPIROLA DUPLEX— far en wire say Header!. SEPARATE' — . TONE CHAMBER FOS EACH PHONE, stlalsstls* Istsrferene QQ QC jMtweta sheets. Setla Maw ftalsh. sMsles tttlast. (Mesel tj)0e03 Oak (00) ' ef' mihitiin' (tiki)' 'selesj' towns' ' Sweet asd* Sttisn.*.'.' I4.M SPISOLA SIMPLEX— *w an win SaMsIa > eretter salt, slack (SB), ask (SO) ead BMBteaay (SM) Helta, naie srlen u DUPLEX. SPIROLA CONCERT— wallets wit* eallt-le salt sad wed Oak (CO) sad aa- keseey (OM) Italia, smews' tarsal .tlt.SS At dealer, or ettteald (C. 0. 0.. If ereftrrad) L- H. D0NNELL MFG. CO., DEPT B, BOX 70, ANN ARBOR. I Digitized by Google

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24 RADIO WORLD RADIO PANELS •"KM" l.t» lt"xS4" 1.M MHifirtm' sasshn tint act hi ted. Awn wealed. PAGBSON COMPANY Bee M. Untaiu Statics. St Leala. Me. SPECIAL OFFER Far a I'mllcd time ooly. RA-IS..SU Grebe CR-S... DA-S. . . M Grab* ROBK. Prim F.B.B. Rod Bssk. N. J. A. V. GREGORY 4S Broad Street Red Baak. Jf. J. Do Yod Like Clear Tone — Sharp and Distinct? If so try MARSH'S Vernier Variable Condenser AT LAST Made la Three Styles. Dial Knob lad Screws Complete. Fully Guaranteed. tT-Plate • SS.5S tS-IMate 9 W.« U-Ilate • S4.X8 Hall order* promptly filled. F. P. Marsh, 145 Nicoll St NEW HAVEN. CONN. The Niftiest Short Wave Tc Only M-M * PP oa 1 It L. W. GOODMAN DREXEL HILL, PA. Doctor , Nerrlstewa, Pa,. ■ nnrmnii, rm la r«M«tly with ay BOODMAN, an era 90 Bliss tat Iraa Saa Frsaslsso. DENVER Mac la aad aiak the sM». "Wl Tom oh To the Man with an Idea I offer a com prshea aire, experi- enced, efficient service tor hia prompt, letal protection, and the development of his proposition. Send sketch or model aad descrip- tion, lor advice aa to coat, search through prior United States patents, etc Preliminary advice gladly tarnished without charge. My experience and familiarity with various arts frequently enable me to accurately adviae clients aa to probable patentability before they go to any expense. Btaklst at ralueble Information, sad form far properly dueMns iw lose, fras on isqasst. Writs today. RICHARD B.OWEN,Patsat Lssrys. It Oeea Baltsiss. Wasklattsa. D. 0. 2270-P Wsshserrh Bid's.. Nan Vtrk OHy Fifty-two issue* for $6.00. Sub. De- partmeat, Radi rid, 1493 Broadway, N. Y. C RADIO WORLD •naspnoN". bbtakt <t»o PUBLISHED EVERT WEUXKPTIAT (Dettd SATUHHAV OF SAME WRICK) FROM I-HIILICATTON OFFICE. _ 149S IIKOAIIWAY. NEW YORK. n. Y. BT HKNNK88Y RADIO PUBLICATION* CORPORATION ROLAND BURKE 11KXNE88T. Prssiamt and K. II tor M. B. 1TBVNEIWY. Vice-President FRED a CLARK. Scenury end atanaatr 14»» BROADWAY. NEW YORK. N. T. ASSOCIATE EDITORS Robert Mackay Robert U Daaikarty SUBSCRIPTION RATES i Fifteen cents ■ espy. to 00 a raar. ft.lt far sis months, fl.50 for thrrs months. Add 11.00 a year sstra far poststs to Caaada ami foreign countries. Receipt by new substrtbtrs of the first cany of RADIO WORLD mallei to thus after mlM la their on let. Is automatic seknowletlgmeat of their proportional rates. ADVERTISING RATESt Ons pane: One time— $150 00. naif. Quarter. Third sad Two- thirds pases st Per strata lias. proiurtlonat* rates. One Inch, coo time— 15.00. to. to. On rear eonsenitlrs Issues, I OK* discount, On thirteen conoteutlfa Isaues. 1J* dlsssaat Corsr and prsferred-noelllea rates suds knot on application. 1* days Not S* 1* days. CLASSIFIED ADVERTISEMENTS! Fire emu i*r word. Minimum. 10 worth. Dis- count of 10% an 4 aonsseullce laruee— 15% m thirteen oonseeuUcs lasuss. Cash with enter. Entered sa second-cues matter. Marsh St. lttt, at the root Office ot Nrw Tack. New Tort, sudor the act of Marsh S. 18TS. IMPORTANT NOTICE! While rrery passible cars Is lakes to state correctly matters of fset snd ojrlsisn la techalssl and seneral writings eororln* the radio flchl. end erery line printed Is sons over with a scrupulous resent for the facts, the publisher ttleelalme say responsibility for stateomta reaardlna quasi lone of patents, priority of claims, the Procter work Ins out of technical problems, or other matters that may bo printed in assd ralth and on Information furnished by those supposed is be trustworthy. This statement la made la rood faith and to ears time end controrersy In swtlsrs evsr which the lanet possibly bars esattaL Organ Recital by Radio WJAX, Cleveland, Sends Out • Fine Program from World's Largest Instrument A N unusual feature recently broadcast .by WJAX, radio station of The Union Trust Company, Cleveland, was the organ recital by Edwin Arthur Kraft, a well-known Cleveland organist, at the new Cleveland Public Auditorium, Tues- day evening, November 28. This program was of especial interest to radio fans because of the unusual character of the organ on which the re- cital was played. _ The Cleveland Public Auditorium organ is the largest in volume of any organ in the world and has been the cause of much interest on the part of musicians as well as much curiosity on the part of the public. It occupies a space 30 by 30 by 20 feet, and requires a force of 70 horse-power to blow it. Three hundred miles of wire were used in its construction. It has 5 manuals, 125 black keys, 180 white ones, 32 pedal keys, and 160 different stops. Each stop gives the effect of a different instrument, any one of which may be played alone or together with any or all of the others, with the result that almost any desired orchestral effect may be obtained. The largest pipe is 25 inches by 30 inches by 33 feet long and the smallest pipe 'A of an inch in diameter and only ii of an inch lone. There is, also, an echo organ placed 325 feet away from the main or- gan which makes it possible for the or- ganist to obtain particularly unique ef- fects. The tonal quality of the organ brings out the broadcasting loud and clear. RADIO rntnt»eiTr«T MFG. f~ . -u," lest ItMMt AVE. NfW roe*, SL T. PRICES SMASHED! Owtni ts Increase In retinas of business i announce drastic reductions Is ser qasUty Send card far eaatpWte list or order from the Ins ssmiils carina. AS rootle prepaid sad within 14 bases after receipt st order. tarnsMs for rebate or sxsheaas. Tee ataspty ba phased! TWO STABE AMPLIFIER PARTS Mistiest SrsSS Mater tale Panel, Bekejlte ?»I2 " t£lam- CsMsst o4_J_»hf weed to St 2 Transformers. Bast ...;:t!:.i 'irlS _ s.ss t FllasMst Rkssetata • SSs ss.... I.SS 2.1* S Tabs sockets, ssas bet.. • ats sa. .t* 1.7* t Tabs socket hrsekcts • Its ss. . .SS .SS 14 LIsSIsi sssta. sick, elet.. • so .42 M 12 ft. si beat ssoiasttl tobies • 4s. At JU 15 lost cesser liaeaitlas wire SS At 1 est Massrlats ihiii wlrUM Setslls .1* .St Frest Ptoses, tOOt straw SI2.SS I2I.SS ....IS.SS ts.ss .... s.ss s.ss Westers Electric. 2MB ohstt S.2S I2.SS Detector Tabes. Ceaalashsm. Ms*.. S.SS S.BS Radio Parte Manufacturing Company IS PARK PLACE DETROIT. MICHIGAN CHRISTMAS OFFER $3.60 Cash or Mssssy Order Only, aad wo UM-UM phone needs. SYKES MFG. COMPANY U SPRINGFIELD AVENUE NEWARK. N. J. At Your Service 1 There appeared in RADIO WORLD, April 1, IS, and 29. the following articles: April 1— A SCO- Mile Radiophone Employing a 5- Watt Tube, by Franlt A. Ilahncl. *rA Me, Plcaae. How Will Thia Set Receiver" by E. L. Bragdon. Short Cuta Va Receiver .Cir- cuit Design, by O. C Rooe. Making a Short- Wave Regencrstor, by Fred. Chaa, alert. April IS— First Principles of Electricity as App'ied to Radio, by John P. Miles. Your Storage Battery, by K. L. Bragdon. What Makea Radio Possible, by Edward Linwood. Ground Connection aa Vital aa Antenna, by Fred. Chaa. Ehlert. April 29— Valuable Pointers oa Aerial Gam- atrurtion, by Edward Linwood. What Is Meant by Tuning, by E. L. Bragdon. Radio- Frequency Amplification and Regeneration, by Frank Armstrong. Honey-Comb Coils and Com- densers, by Edward Linwood. Charging the Storage Battery, by E. L. Bragdon. How to Construct the Vartocoupler, by Frederick L Rumford. Each copy aent on receipt of 15c. per copy, or the thtee copies for 45c. ; or better sun, send your subscription beginning with any one of these numbers, and we will send this paper for 52 iaaue, and you will then have a complete file for ready and content refer- ence. RADIO WORLD. 1493 Broadway, Hew York. Digitized by Google

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RADIO WORLD KDKA Breaks Its Record to Mane Picked Up by Stoamer in South Pacific Ocms, 5,»M Mil** Away BROADCASTING a concert S.000 miles is the proud record of KDKA, the radiophone broadcasting station of the Westinghouse Electric & Manufac- turing Company, East Pittsburgh, Penn- sylvania. This latest achievement of KDKA, which first started operating November 2, 1920, was brought to the attention of the Westinghouse broadcasting officials on the receipt of a postal card frou E. G. Osterhoudt, radio operator of the steamer "J. A. Moffett," in which he tells of hearing KDKA while off the coast of Peru, a distance of, approximately, 5,000 miles. The card, which was mailed in San Pedro, California, contained the follow- ing: "Westinghouse Electric & Manufactur- ing Company, East Pittsburgh, Pa. \ KDKA Gentlemen: At 9:30 p. m. (local time), on October 5, while off the Peruvian coast, 3.453 south of San Pedro. California, I heard your phone on 360 meters, playing "Stumbling." The QRN was quite heavy but I am positive that it was your plionc. I am using a honeycomb set with an audion detector (Audiotron). Please verify this, if possible, and oblige, Very truly yours, E. G. Osterhoudt, Opr. S.S. 'J. A* Moffett,' care Radio Corpo- ration of America, 109 Stcuart Street, San Francisco, California." This request has been verified by a glimpse into the back programs of KDKA with the result that this station has broken its own broadcasting record which was set last spring when a ship in the port of Iquique. Chile, heard an entire concert. The distance of the ship from the broadcasting was approximately 4,200 miles, so that the new record beats the old by 800 miles. To many aasioua inquirer* RADIO WORLD has no fro* U»t On* copy is •oat at a voucher to oacli advertiser or •dvorthiag agrat represented in current iesuaa. All other copioa ar* paid for oa ntwcriatioa or through tk* now* trad*. DELICATE SOLDERING both Um mauafacturcrs1 amateurs* problem on all Una work Is rairtliy solved by th* instrument cons traded (or this particular purpose. THE POST 80LDERING IRON Platinum Heating UniU-Intcrcbangcabl* Tip— UniTcrsal Currant Om Half Artaal ate $6.00 From Your Dealer or Writs Awarded CertiOeat* of Excellency. N. Y. Evening Mail Radio Institute POST ELECTRIC COMPANY, (DW. 509) SO E. 42nd St, New Tar. SometKW Brand New ir^Aj»±ervr\a wir pay a liberal commission. Previous experi- ence not needed, as we give our representatives full detail instructions and every possible assistance and help. II rite telling us all about yourself —a :e. education, business experience — and we mil immediately give you full details. Telling you just hotv you can materially increase your income DO IT SOW . COMPENSATION RADIO WORLD 1493 BROADWAY NEW YORK CITY

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26 RADIO WORLD Complete Your Radio Library for 1922 Technical Articles Published in Radio World to Date of Inductance Colli, by Fl APRIL 1. A 600-Mile Radiophone Employing a 5-Watt Tube, br Frank A. Hahnel. "Tell Me, Please, How Will This Bet Re- eelTeT" to 1 U Bragdoa. Short Cuts In Receiver-Circuit Design, by O. C. Rooa. Making a Snort- Wave Recenerator, by Pre*. Chan. Bhlert, APRIL* 8. Do Ton Know Tour ReeelTtag Equipment, by James D. Gordon. Why a Crystal la Called a Rectifier, by Wal- ter Bramctt. la Radlotelephony Dependable T by O. C. Rooa. Mounting Crystals In Tour Detector, by B. L. Bragdon. Storage Batteries for Radio, by Fred. Ghas. Bhlert. APRIL IS. First Principles of Electricity as Applied to Radio, by John P. Ml lee. Tour Storage Battery, by B. L Bragdon. What Makes Radio Possible, by Mward Lla- d. Cbaa. Simple Receiver, by around Connection aa Vital as Antenna, by Fred. Chaa. Bhlert. APRIL 29. Valuable Pointers on Aerial Construction, by Bdward Llnwood. What Is Meant by Tuning, by B. L Bragdon. Radio-Frequency Amplification aw" ration, by Frank Armstrong. Honey-Comb Colls and Condensers, by Storage Battery, by B L ward Llnwood. Charging the Bragdon. How to Construct the Varloooupler, by Fred- erick J. Rumford. MAT 6. The Advantages of Radio Frequency, by Harold & Potter. How to Construct, Protect and Operate a Storage Battery, by George W. May. The Beginner's Catechism, by Bdward Lln- wood. Tuning and What Is Meant by It, by Chaa. Bhlert. New Frequency Amplifier Brings Waves In Strong, by G. W. Msy. MAT IS. My Practical V. T. Detector and Two Stage Amplifier, by Frederick J. Rumford. The Prlnotpli tar J. Howell. Principles of Radlotelegrapby, by Wal- The Reason for the Loop Aerial, by George V. May. Tuning and What Is Meant By It, by B. L. D. Beginner's Catechism, by Bdward Lin- Sragden. The MAT 2a The Design of an Amateur Receiving Set. by C. White. The B Battery and the Plata Current, by George W. May. Radio Terms at a Glance, by Fred. Chaa. Bhlert. The Beginner's Catechism, by Bdward LAm- Flre Undewrltera* Rules, by Fred. Cbaa. slot*. MAT 27. The Beginner's Catechism, by Bdward Lin- tod. How to Make Tour Own Condenser, by George W. May. Tuning as Applied to Telegraphy, by Walter J. Howell. . Why the Condenser Doesn't Condense, by B. L. Bragdon. Making 81gnals Louder with Two-Stage Am- plifier, by George W. May. JUNB 8 The Cost of a Single-Circuit Receiver, by Howell W. Miller. The Beginner's Catechism, by Bdward Un- How to Compute and Build a Fixed Coaden- ser, by B L. Bragdon. Design for an Amateur's Receiving Set, by C. White. Simple Method of Recharging a Storage Bat- tery. By John Grayson. JPNR 10. Radio Receiver for 8bort Waves, by George W. May. How to Filter Atrooepberic Condition*, by C. White. The Messenger Boys of Broadcasting, by B. L Bragdon. Are Vnu a Member of the N O D C. t by B. L. Bragdon The Beginner's Catechism, by Bdward Lin- wood. How to Construct One- and Two-Slide Tuning Colls, by George XT May rrrNF 17 The Vacuum Bulb's Start In Life nv C. White. How to Select the Rlgl/t Set. by R L Brag- dan. The Beginner's Catechism, by Bdward Lin- Test Bhlert. Shun Wsvea from a Stanley Bryant. JUNB 24. How 10 Make Tour Kadlo Cabinets, by W. 8. Standitord. How the Crystal Detector la Osed to the Beat Advantage, by C. J. Williams. How to Construct s Long- Wave Regenera- tive Receiver, by George W. May. Tested Invention of Major Armstrong Ampli- fies Set 1UO.O00 Times, by John Kent. Repairing Cracks in Hard-Rubber Storage Battery Jars, by W. 8. Standitord. The Beginner's CateehUm, by Bdward Lln- wood. JULY 1 Novel Unit-Detector and Amplifier, by Fred- erick J. Rumford. Why You Must Use a Condenser, by C. J. Williams. How Wave Lengths Tret el. by Fred. Chaa. Bhlert. Radio World's Revised Dictionary, by Fred. Chaa. Bhlert. The Beginner's Catechism, by Bdward Lln- wood. Use of the Vacuum Tube Detector, by George W. May. JULY 8. Radio's Place In the Phenomena of Nature, by B- L Bragdon. The Function of the Loom Coupler, by Charles H. Plath. Armstrong's Superregenerstlve Amplifier Fully Explained, by John Kent. Operating a Transatlantic Station, by Fred. Chaa. Bhlert. The Beginner's Catechism, by Bdward Lln- wood. Reducing Strays and Static, by Fred. Ghas. Bhlert. JULT IB. Assembling s Detector and Two-Stage Ampli- fier, by H S. Stanford. Combined Radio and Audio Frequene* Ampli- fication, by C. White. The Beglnner'a Catechism, by Bdward Lln- wood. Locating Your Aerial, by Harold Day. Facta for Beginners, by Fred. Chaa Bhlert. JULT 22. When Tour "Movies" Come by Radio, by Stan- ley Bryant. Underlying Principles of the Vacuum Tube, by George W. Msy. Practical V-T Detector Panel, by Frederick J. Rumford. Revised Radio Dictionary, by Fred Chan. Bhlert, The Beglnner'a Catechism, by Bdward Llnwsejd Importance of Aerials to Radiation, by C. White. JULT 28. The Vacuum Tube as a Transmitter, by Charles H. Plath. My 20-KUowatt Tube and Its Uses, by Irving Langmulr. Importance of the Capacity Switch, by B. L Bragdon. The Truth about Lamp- Socket Aerials, by Harold R. Hart, AUGUST 6. How to Construct and Operate the Superregenerative Circuit, by John Kent. Using Radio Frequency to Bartend Range, by George W. May. Things Every Radio Fan Must Know, by nV B Hawley. Revised Radio Dictionary, by Fred Charles Bhlert. AUGUST 13. The Work of the Audio-frequency Transformer, by George w. May. Practical Measurements of Capacity and In- ductance, by W. A. Dickson. Experimenting with Armstrong Circuit Pro- duces Unuausl Hook-up, by Dr. O. 8. Kelly. - How to Secure Perfect Regeneration, by Chaa. Ehlert. AUGUST 19 How to Build a Portable Field Busier, by De Witt H. Thompson. Using Two Tubes for Receiving, by C. White. The Storage Battery s« sn Important Factor In Radio Reception, by Donald Van WyeJi. The Use of Capacity In a Circuit, by George W Msy. The Beginner's Catechism, by Bdward Llnwood. AUGUST 26 How to Build a Spider-Web Receiver, by Frederick J. Rumford. My Detector and One-Step Amplifier, by Fred. Chaa. Ehlert. The Beginner's Catechism, by Edward Lln- wood. Hints for Fans, by C. F. Rye. SEPTEMBER 2 Generating C-W for Transmission, by C. White. Wonders of Radio-Frequency Amplification, by H. S. Potter. How to Connect the Elertrie-T.lgnt Socket Aerial, by John Kent. Practical Circuits for Regenerating Loud Sig- nals, by O. 8. Kelly, SEPTEMBER 8 Radio Ideas for the Amateur to Teat Out by Carl Maason. How to Make a Practical Wave-Motor, by Frederick J. Rumford. How to make a Honey-Comb Coll with a Two- Stage Amplifier, by Fred. Chaa. Bhlert. Perfect Short- Wave Radio-Frequency Amptl- flcatlon, by George W. May. SEPTEMBER 16. How to Make a Two-Tube Superregenarator. by Frederick J. Rumford. Methods of Amplifying Radio Signals, by B. Bradbury. Voles Distortion In Vacuum-Tuba Receivers, by W. A Dickson. Charging a Battery— from a French Radlolst's Point of View, by Marl us Thouvala. Working Diagrams for Beginners, SEPTEMBER 23, 1822 New V T Hook-up Worth Testing Out, by P. F. Metsler. New Method for Lighting Filaments, by C White. Why the Radio Compass Is the Fighting Element of Science, by Ortherns Gordon. Complete Table of Symbols Used In Radio Reception, by Fred. Chas. Ehlert. The Radio Primer, by Bdward Llnwood. Complete Method for Building an Electron- Tube Detector Unit, by Experts of the United States Bureau of Standards. SEPTEMBER SO, 1022 Increasing the Wave Lengths of a Receiv- ing Set, by George W. May. The Importance of the Variometer to a Re- ceiving Set. by Donald Van Wyck. Successful Stunts of an Amateur Radlolat, by C. F. Rye. Employing Jacks with a Two-Stage Ampli- fying Receiver, by Fred. Chaa. Bhlert, OCTOBER 7. Superheterodyne Receiver aa Applied to the Armstrong Superregenerative Circuit, by Charles R. Leutx. Constructing a Radio-Frequency Regenerator, by C. White. Why the Open Antenna la Best for the Radio Listener, by C. D. Wagoner. Broadcasting Stations of United Statea and Canada. The Radio Primer for the Beginner, by Lyan Brooks. OCTOBER 14 Nest Home-Msde Tube Socket, by Gordon & Arthur. Vessels Now Guided Through Fog by New S*?£m °A RadJotelegTaphy, by Otherua Gordon. .What Makes the Receiver Work, by Donald Van Dyck. Using the Varlocoupler in a Short- Wave Re- ceiver, by George W. Msy. Regenerative V-T Receiver for Short Waves, by Fred. Chas. Ehlert. OCTOBER 2L Important Improvements in Radio Receivers, by C White. Be Sure of Your Ground Connection, by Fred. Chas. Ehlert. How Radio Was Installed in Our Home, by Hsttie Briggs Hartman. One-Tube Regenerator Hook-up for Loud Sigs, by Harold Day. Every Radio Set Haa a Reliable Range, by John Kent. The Theory of Radio Communication, by Horace Beers. OCTOBER 28. .A„,lm.p,e Super-regenerative Receiver, by Har- old S. Potter. Vacuum Type of Arrester Safe, by Fred. Chas. Ehlert. How to Make Your Aerial Function, by Horace Beera. 10w !£. Avoid Interference When a 360 Meter and a 400 Meter Station Are Operating Simul- taneously, by C. W. Horn. „ . NOVEMBER 4 Receiver for Amplifying Weak Signals, by Hor- ace Beers. How to Learn the Code, by Ortherus Gordon. ™Det,e,?,ors~~"nd How They Work, by Donald Van Wyck. One of the Moat Delicate Parts of a Receiver, by George W. May. Wave Meter for Amateur Operators, by United States Bureau of Standards Experts. NOVEMBER 11 How to Build a 100-Meter Concert Receiving Set. by Frederick J. Rumford. WiVe Field for Experimenting with Aeriala. by Donald Van Wyck. Single-Tube Superregenerative Receiver, by C. White. Utilizing Ford Spark-Coils for Audio- Frequency Transformers, by Ortherus Gordon. Why It Is Necessary to Tune In, by Arthur O. onirt. Amy aingio copy of Radio World, be- ginning with No. 1, mailed on receipt of 15 cents postpaid. Any seven issues for $1.00. The full 32 numbers sent for $3.75. Or send $6.00 for 1 year (52 numbers) and hawe your subscription start from No. 1. Radio World, 1493 Broadway, Now York Digitized by Google

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RADIO WORLD 27 New Bureau of Standards Radio Literature TO meet the increasing interest in the use of radio-receiving apparatus, the Bureau of Standards of the Department of Commerce is publishing a series ot circulars descriptive of simple receiving sets The first two of this series are Bureau of Standards Circu ars No. 120 and 121. These two circulars describe the receiving sets which use crystal de- ectors. The third paper of this series is Bureau of Standards Circular No. 133 and may be obtained from the Superin- tendent of Documents, Government Printing Office, Washington, D. U at 5 ThTs* circular is a description of.an elec- tron-tube detector, and gives instructions for itsli*fe«on. A receiving set em- ploying an electron-tube detector is more sensitive than a set employing a crystal detector, and may be expected to give mo" satisfactory results. The tuning devices, antenna, lighting switch, ground connection, and telephone receivers with which this' electron-tube detector is used may be those previously described in Cir- culars 120 and 121. „ Broadcast Bill's Radiolays By William E. Douglas HAD some snow out here last week, first we've had this year, reckon that's to let us know winter's gettin' near. 'Course winter has advantages, there's nothin' much to do, no corn to plow, er cultivate, but there's a cow er two that every mornin', hot er cold, to milk out in the shed, while all you city fellers are tucked in yer comfy bed. With winter there comes Christmas time with all its joy an' cheer, which after all, I reckon, is the best time of the year. With snow an sleet comes coastin' an' a lot of bob sled rides an' when the creek is frozen we kin skate a bit besides. I've noticed, too, in winter, radio "comes in" the best, which bein' true I s'pose I should ferget about the rest of winter's inconveniences like thawin' out the pump, with weather down to zero, when yer swing yer arms AETACO TUBE SET 1 Rheostat 1 W. D. U Socket 1 W. D. 11 Tub* 1 Grid Leak Condeneer 1 "B" Battery, »V4 vol's 1 "A" Battery, dry cell 1 Variocoupler 1 "a" Plato Coodeneer A1 A .90 Wire tor Hook Up Free \1 II^T 1 Panel, 7%xU% «P* V Complete German Cryotal Set Sdbt Condenser. *•*»•> ^"J*"™! w|L*d in handsome finished cherry e^taE taOmbTchant*d to tab. ^ mt Federal Phone. **M Jacobus Lightning Arresters $6.60 SLEEPER UNITS Radio Frequency Amplifier ***» Detector UnJta RADIO BLINKER SET Equipped with Electric Li»ht far MorJVTel.er.ph and Bux«r for Wireless. Regular price $ZJ«. Spe- cial **•*■ Short Wave Reeenerative ^rith Special Variometer Inclosed to Mission TOak Cabinet.. ***** Standard Variometers, Special W-S» Formica, $Z-0« a pound. Cut, drilled and engraved to order. American Electro Technical Appliance Co. 23S Fulton Street (mall orders) 1M7 Broadway New York City Mote. BecsuM of • rltlns market In ra*e HiMlui. thSU price, srs not .uarantotd liter AFTER XMAS Needs Can Be Supplied By Us At Special Price Complete One Tube Outfit Guaranteed Special Type for Broadcasting with Bulb, Batteries, Phones, Aerial *Z7J» Phones Western Electric, in Original Boxes, $15.00 Type fM Federal, $8.00 Type Auth, $8.00 Type «• Kellogg, $12.00 Type *■•» Seibt, Adjustable, $18.00 Type MS Westinghouse R. C Set The Famous Broadcasting Set $7».7S an' jump to keep up circulation. Gosh! I hate to do the chores when its as cold inside the barn as it is out of doors. When I get up these mornin's it's as dark as pitch outside an' 'fore I get the chores done I am almost froze beside. Last week I caught an awful cold, worst one I've had fer years. My nose wuz like an eight-day clock, an* eyes chuck full of tears; my back ached an' my head ached, I felt ninety-four years, old. I wish some doc could find out how such things could be controlled. I soaked my dainty feet in mustard baths till they were pink— I'd hate to tell you how much lemonade _Min made me drink. All wrapped up in a comforter there's nothin' I could do but listen to my Radio an' I wuz feelin' blue because on every Tuesday night they broadcast singin' lessons which helps me find an outlet fer my musical expressions. While I don't need no lessons still it keeps me up to date on how to tell the other boys who ain't so fortunate. But Tuesday I wuz feelin' bad. it kinda got my goat— all stuffed up with that cold of mine I couldn't sing a note. (Copyright, 1922, Westinghouse Electric & Manu- facturing Company) COMPLETE YOUR FILE OF We Want Your Name •a • setts! oar*. Wo Mil llko to sot the saaw rt s^yMDIO WORLD r«*r. oond out a ■ssilal amnio Is oar rssdoro. It »IM iRtvut you. Bs oure to tend ao your earn os L ,S£l Sri snd addreio It 8IFT DEPT.. RADIO WORLD. 1493 Broadway. N. Y. If yon did not get a copy of Radio World No. 1 send as |6.00 and we will send yon the paper for one year, and start it with our first issue, which will be mailed yon as soon as possible after receipt of order. " SEND 118 THE NAME OF YOUR RADIO CLUB WORLD. 14** Broadway, New Tor*. Double Slide Tuner Set Complete with $8.00 Phones, Crystal De- tector, Fixed Condenser, Aerial, Guar- anteed »!«• Federal Crystal Set* Complete with Phones, Aerial Loud Speaker Horns Just Attach One Phone, Wonderful Tone.... SS.7S Vacuum Tubes for $1.00 With every $&*• purchase. These tubes are tested before shipping, and we offer them this way, as many of our customers will want parts to complete their outfits, such as "B" batteries, etc, and an extra bulb Is always acceptable whoa it can be purchased for an additional SlJa. A Few More Antenna Plugs At a*e. Tuska 4" Dials While They Last sac A Few More Variocouplers At He RADIO MAP LATEST EDITION Featuring: District Divisions, Time Division*, and All U. S .and Canada Broadcasting Calls 35 Cent* Above) Map Given Free with $$.» purchase until Xmae. A'.l specials in November and December issues o/ RADIO WORLD are good now except UV2O0, I7V201, WOll and VT-1 tubes. Postage must be included with, order. Checks must include 10c. exchange and please have them certified. All goods are shipped P. P. insured. RADIO DISTRIBUTING & AUTO SUPPLY COMPANY 64 West 66th Street, New York City Phone Columbus SSM Broadway-7th Avenue Subway Digitized by W or 9th Avenue^t

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28 RADIO WORLD TOBACCO HABIT BANISHED QUICK, SURE. LASTING RESULTS Tobacco Redeemer banishes the habit com- pletely, almost before you know it. An absolutely scientific, thoroughly reliable treatment. No matter how Ions the habit, or in what form used, yon will have no craving for tobacco after you take this pleasant. Inexpensive treatment. This we positively guarantee. Your money returned without argument or question If not satisfied. Write for free explanatory booklet and proof of what Tobacco Redeemer haa done for men addicted to the tobacco habit. Send postcard or letter today. I Cfc, stapL IT 1 ,SL Lawit, at*. GITHENS TRUTONE RADIO HORN— LOUD SPEAKER ^f-Sjfll-W First one to A on ten day trial Retail Prlew hum Incladea Load Speaker Tnitooe has been pronouncsd the beat on the markat by expert*. It has • clear, true tana B"nr rsdle fan should try Trutana and tampan It with others. If TOU don't find Trutone the bast, yottt atoney wlU k. rrfundsd. It l. ..id on . tsn^dayM gg**'* suarantaa. If not earn »d by your dealer write ua DUtHbutort and Dealer; write! AUTO PARTS MFG. CO. 1818 Trombly Ave. Detroit. Mich. FRS ALL MOLDED UNIVERSAL COMBINATIONS ■ UwKe n S F. R. S. Molded Vartometers » F. R. 3. Varlocouplers * F. R. S. Molded Bank Windings Bank Wlndinca are tnterchangeaOle fee direct mountlnc on either Variometer or Varloeonpler. Universal — Accurate — Interohanawahlo Bet Inoludea twe Federal Traaafi Condenser, twe-meldad varte molded varloeoupler, three V. T •.lament rheostat*, dlala. hia dinar peats, awlteh posnt* tiv* cabinet and drilled panel: complete, ready to hook np. A |lt( Radio ( for P. R. S. Radio Corporation 4M-D Fort St. That Armstrong Circuit So much interest has been displayed in the special article, "TESTED INVENTION OK MATOR ARMSTRONG AMPLIFIES SET 100 nm TIMES " by John Kent, that appeared in RADIO WORLD No. 13, dated June 24, 1922, the publisher decided to put aside a number of copies for those who were not -hl* *ft t" this issue when pub- lished, of 15c, or year (52 •• months, the isf Armst Uroat? t, postpaid, on receipt cription, $6.00 for one lonths, or $1.50 three vill be started with irticle about Major mo world, urn Radio Romance By Dr. Frank Crane FEW of us realize the romance of radio. To very many it seems to be merely another form of amusement, another me- chanical device in addition to talking machines and pianolas. There is a very large number of people, however, to whom radio opens up a new world. If you will take into our imagination the picture of the many who are shut in and have little communication with the outside world we begin to see in radio wider possi- bilities for enriching life. Hospital patients can redeem their hours of loneliness by listening in. The concerts and lectures and stories broadcast from central stations, affairs which may not be alluring to those of us who are vigorous and well, are to these people a godsend. Henry Smith Williams calls our attention to the remote workers on the frontiers of civilization. "Imagine yourself," he says, "a lumberjack working month in and month out in a northern logging camp, which you leave at most twice in the year, on Christ- mas and on the Fourth of July. For months together you are shut out from all physical contact with what we ordinarily speak of as the world. No newspapers, no letters, no rumors even of what is going on a hundred miles away." Then, with a simple radio outfit the lonely man may take his place at the world's table and resume his touch with humanity. Then let your imagination call up these things : The lonely lighthouse or lightship, where men live for months in solitude. The explorer, far from civilization in the forests of Canada or the jungles of Africa, being able to keep constantly in touch with those at home. The Desert of Sahara, which is already dotted with radio stations from which French garrisons receive instructions. Alaska. Recently the first station was es- tablished at Fairbanks. The Boy Scouts. Especially in England, the boys are using radio. With a radio out- fit there is no excuse for getting lost. The detection of crime. William J. Flynn, former Secret Service chief, says that radio is especially valuable in broadcasting descrip- tion of criminals. The use of radio on ships in remote parts of the sea and on air vessels. The influence of radio in unifying human- ity. Dean Schneider of the University of Cincinnati, says : "What perhaps appealed to me more than any other phase of the possi- bilities of the radio telephone is its potent in- fluence in bringing together all peoples of the world, in cementing human relationships, in doing away with discord and promoting international understanding and sympathy.' Finally, think of how radio could be used by Arctic explorers. Every one of these items is intriguinsr to the imagination.— From "The Globe," N. Y. (Copyright, 1922, by Frank Crane and "The Globe," N. Y." PATENT Hears Her Own Play by Radio AS Miss Zona Gale, famous author, listened in at her home in Portage, Wisconsin, one evening, recently, she heard the voice of WGY, broadcasting station of the General Electric Company, speak her name and convey the greet- ings of the studio players who were about to present, as the evening's pro- gram, the play made from her book, "Miss Lulu Bett." The following day, her acknowledgment came in a telegram to WGY in which her manager, F. L. Van Epps, said: "Miss Gale acknowledges your greet- ings. Lulu Bett coming through fine." The play was given by the studio actors of WGY, headed by Edward H. Smith. Yew OsJ Fill ADVICE. Vaetaa— laea with dial. Vill i «■■■■ with AiaU afesMtf Be*a #* as* JaTsl/aHerw OSLAND, INC nrm av. Look Spider Web Inductance and Discs that give the wonderful re- sults as described in Radio Age. Die* Only Dtssrrasa tor ■ We are manufacturers of Stor- age Batteries for Radio A and B circuit WRITE FOR PRICES International Battery Co. 112 Louis Street. N. W. Grand Rapid*, Mich. The Moat Useful NEW YEAR'S PRESENT! A Year'* Subscription to RADIO WORLD (52 numbers) $6.00 tl a year extra for postage 1 1493 Broadway

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RADIO WORLD AMDKAN ELECTRO PHONE CO, be an ram atimci, hiw tow OI8TBIBDTOBS Fail Um of Kattoaally bm KaaJo Ma Pino—It to fobbert emd doattn. Cpiaaet 23 Plate $1.00 Ffaaaet 43 Plato $Uf Fl MM Ok— $3.52 C—k with Order RADIO ENOINEERINO COMPANY Put* An. a Unci) UP A** mm a Vaar for Forola* *** Caaadiaa Footage. INCREASE YOUR CRYSTAL RANGE BT CBIJKO A ~tt~ CLTM-ODfajTrfB CONTACT W TOITI CKTSTAL DhTTBCTOJa I. It Jjwaaa i iarlln tart leiajeaj. ata ISfisMJa^ auMvfrM) waTav la) SVttVQF* S* Vr^MaMaBHTMB taTJuTAuTAaa* awaat fJ^JM^aMji puarl^SS v9Sa PrftMa WHat kaM^VitttaMa fflMaMy*WM) MM. TT CBYaTAX CONTACT OOMTANT Bai IMt BOSTON t RADIPHONO ADAPTER $2.00 Hot. U aa rC'.rltc.i aea nomlMl wmy lo um rum Tlttrala. aVllaor.. Mt.. U a .[ .mkrr Thl. adapter la of avaJJad aa ■aaUUBM U ba aatlafartorr or Booty rafuixJaJ. If rour daalar lanM aupnlj rou Mod aa IS M wa wlU aaU ana br WJxaj paat prapald loduatrl.l 8alr. Kmlnaa-rlr., Qa. t7l BraaO straat. Nr. art. M. I. ■■■■■■■ I surprised? werepair Vacuum0- TUBES • aaam HARVARD RADIO LABORATORIES t, htaaa, Pane) Paat OvO-P. "Button, Button, Who's Got the Button?" THE old game, "Button, Button. Who's Got the Button" hat just been applied to radio broadcasting. When the younger radoists meet, they ask one another how many radio buttons they have — the one with the greater number being the winner. Several stations now have individual buttons and many others have orders on file. W. Dandridge Ter- rell, jr., fourteen-year-old son of the chief radio inspector, of the Department of Commerce, is the "inventor" and owner of the new radio-button scheme. He is supplying broadcasting stations with identifying buttons of different colors bearing their name. call, and frequently their slogan. Distribution of the buttons is made by the stations to listenert-in who report having received their broad- casts. Many fans are already pridefully dis- playing the buttons of their favorite sta- tions on their coat lapels or on banners hung on the wall over their receiving sets. Those possessing the most but- tons are local champions. As new broadcasters adopt buttons, the scope of the game increases and there arc more buttons added to the pen- nants of the receiving stations. A prize pennant is planned tor the receiver se- curing the most buttons in a given time. The young inventor, who !s a pupil in ■\ic Force School in Washington, is be- in \ ed to have started something new in the way ot advertising and both broad- o.iMit'g stations and tans are enthusiastic over the plan. Among the first stationt to adopt buttons were W'SR. the Atlanta •Toiirnal" and WKAA. "The News." I lall.is. Texas. Digitized by Google

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RADIO WORLD DO YOU WANT TO BUT, SELL OR EXCHANGE RADIO OR OTHER GOODS 7 DEPARTMENT AT k A TRY THIS RADIO WORLDS QUICK-ACTION CLASSIFIED ADS This department is intended for everybody who wants quick action on short announcements covering the buying, selling, exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that it pays to read these column* every week. Advertisers will get a ten-day service here — that is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy reaches us. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. per word (minimum of 10 words, including address), 10% discount for 4 consecutive insertions, 15% for 13 consecutive insertions (3 months). Changes will be Bade hi standing classified ads. if copy is received at this office ten days before publication. RADIO WORLD CO., 1493 Broadway, N. Y. C (Phone. Bryant 4796). VACUUM TUBES repaired reasonably. Setts- faetfoa gnaraateed or coat nothing. Vaenem BeclTuB, MM Derr. Toted*, O. SILVER MIRRORS-PLATING OUTFITS FUR- NISHED—Stop daily grind. Plana free. Eatab- Kthed UK CLARENCE SPRINKLE. Dept. t. Marion, Indiana. INTERESTING LET- FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO." Write today complete Hat of script ion oner. CoL OLD MONEY WANTED— S2.00 to $500.00 EACH trecBracna and oar so* rial sob- "RADIO." Padic Bid*.. Saa paid tor hundreda ol Old and Odd Coma. Eaea> all old money. Send 10 centa for New Illustrated Coin Value Book, 4x6. You may have EXCHANGE JOLLY. . rSRS throngh ear crab. Stamp tatty Lee, Inc., 484 Broadway, New ippreciated. York City. PATENTS IHeutilual eaaea a specialty. B. P. Hssdj i Bagmtered Patent ana.. Wnslign i. D. C WE WANT YOUR NAME— On a postal card. We would like to get the name of every RADIO WORLD reader, aa we expect to send out a apecial meaaage that will internet yon. Be eure to send ua your name on a postal card and ad dreas it, GIFT DEPT., RADIO WORLD, 1499 Broadway, New York. NEWS Me. ier OF THE STAGE Send FOR SALE— No. A-l Gorton Engraving Ma- chine and aet of Radio letter*, in good condition. Will aell cheap or trade for radio •applies. L. S. Hitter, 414 Deaderick St., Nashville, Tenn. RADIO FANS: Have yon read of the won- derfnl new all-wave Radio Freeneocy AmpUaer invented by Doctor Miller of the Naval Radio Research Laboratory, Bureau of Standard*, Wash- mjrtoo, D. CI We manufacture this device under license. May be added to your present act, giving wonderful reaulta on distant • tattoo*, ar easy be made up into loop receiver eeta with net reme range and beautifully clear reception, far home or automobile use. Besides being the beet amplifier on the market, the Miller eovera all wave* at equal efficiency. Price, $6.50 per unit. Detail* free. Coast Radio, Inc., EI Monte. Los Angeles, Calif. copy of NEW YORK STAR the great Uraatrated theatrical weekly. S4.0S year, 10.00 six month*, (LOO three months. New York Star Co.. 1499 Broadway, N. Y. DID YOU GET THE XMAS RADIO WORLD? This was our attractive iasue of December 9. Mailed on receipt of 15c.. etarap* or coin— or aub- •cribe and have your »ub»criotion begin with XMAS number. RADIO WORLD, 1493 Broadway, New York. WE NEED RADIO WORLD, dated April 22 and August 5. If you have copies you don't re- •■ire, mail to this office and current issue* will fie sent you for them. RADIO WORLD, 1498 Broadway, New York. To your personal addrese: Radio World, 1 yoar (52 numbors), SR. coin*. Get potted. We pay CASH. Clarke Coin Company, Ave. 83, Le Roy. N. Y. EXCHANGE LETTERS with friends everywhere. Pleasant paatime. Information for stamp. Smith, Box 3125, M. Portland, Ore. USED RADIO APPARATUS bought, sold and exchanged. Write, if interested. Roy McCon- nell, Ravenna, Nebr. BROADCASTING MAP of the United States appeared in RADIO WORLD No. 8. Sent on receipt of 15c, coin or (tamp*: or •tart your aubacription from that number QfSM for 52 issues). RADIO WORLD, 14SJ Broeshrny. New York BUY "BILTRITE" PRODUCTS DIRECT FROM MANUFACTURER. Save 35%. Variometers, mahogany, green silk wire, apecial machined hard- ware, $3.50; Variocouplera to match, $2.85; Con- densers, 23 aluminum plate, $1.65; 43, $2.15; Dou- ble Circuit Jacks. 45c; $1.25 Plugs. 65c; etc Lit- erature. WAGNER NOVELTY CO., DELPHOS, OHIO. LIGHT— Make a flash-light without the use of batteries or bulbs. Instructions for making, 25c H ft M Specialty Co., Box 66, Brighton, Mass. LATEST— BUILD a curiosity clock for the home. Instructions. 25c. H & M Specialty Co., Box 66, Brighton, Mass. Radio Club News THE Radio Experimenters League an- nounces on its letter heads that it is "Run for amateurs by amateurs." If in- terested write William Guild, Secretary, 68 Glen Ridge Avenue, Glen Ridge, New Jer- RADIO WORLD as a Holiday Gift Have You a Friend Who Is Interested in Radio as an Amateur or a Fan? The Princeton Radio Club announces that messages will be transmitted free for under- IF so, yon must know that such a friend would wolcoma a yearly subscription graduates to any part of the United States for RADIO WORLD from yon. Send u. $»M and w. wfll place the name or Canada. Its members have agreements tor suwsv "VKi. ' , _ . . . m . with other amateur radio outfits for the re- of your friend on our mailing list for the coming year, end also we will send )ayjng of messages for points beyond the • apecial notification to your friend to the effect that RADIO WORLD will be range 0f its so-watt set. With this set, how- sent for 52 weeks to his address with your compliment*. Send In a yearly order, ever, the Princeton operators managed to get so that the firat copy and our .efaowUdg-ent of your conrtesy to yonr friend ^J^Bgg? will be received before Christmas. i of tha, power, ,t js believed. The club has AdeW S-hecription Depmrtment, RADIO WORLD, 14B3 Broadway. New twenty- fi^member^ ^ ^ ^ York, N. Y. meets every Tuesday at the Christodora . House, 147 Avenue B, New York City, at 7 :45 p. m. sharp, has room for new mem- " — j)ers_ wjtn a ijtt]e knowledge of radio. The __ . p. . . n, | club members have donated two buzzer-sets Hobday Gift Subscnption Blank ^e ^th«-rS2 RADIO WORLD, Smith, of Plainfield, New Jersey. It is 1493 Broadway, New York, N. Y. desired to have only boys who reside in the nichborhood of Tompkins Square, between Enclosed find $6.00 for which send Radio World (52 numbers) for the coming Fifth and Fourteenth streets. Applications year. 1923, to the following address: femX^tarT Egh^wS *£ Name Club. 250 Avenue B. New York. The Young Men's Hebrew Association. Address 92nd Street and Lexington Avenue, New York Citv. has installed a large radio re- ifven^tRADIO WORLD Ci,y and State ceiving-set which will be used for a number will be *ent with my com- of purposes. The educational department pliments for the coming year. wj]| giVe a course in radiophone operation If :„h to gend more My Name and construction which will be open to mem- ' ription. write hers of the association. The entertainments ■s and ad- Address which are held from time to time will get ara't ¥Fk . - the benefit of the concerts and other nam- ^each add.- C„y a„d S,gU ^ broadcast

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RADIO WORLD Answers to Readers 1— Is it possible to use UO-V A C with a step-down transformer and potentiometer to light filaments? 2 — Where may they be purchased? 3 — Can W D 11 tubes be used for ampli- fying as well as for detection? 4— -Would several turns of insulated wire strung around the room be of any use as an aerial for a powerful regenerative set? 5 — Are the W D 11 tubes as good as the regular tubes using 6 volts — L. L. Hamilton, Topsham, Maine. 1 — While this can be done, you will be troubled with a constant 60-cycle hum in your set This is especially noticeable with the regenerative circuit. A filter circuit may be built for this use, but it is less trouble to use the regular A battery, and better results . will be obtained. 2 — Potentiometers may be purchased in any stores handling radio goods. ~3 — These tubes have been used success- fully both as detector and amplifier. 4— You would probably be successful in doing this if you used about 150 feet of wire, but an outside aerial is advisable wherever possible. 5 — It is impossible to discuss the merits of various competitive radio tubes in these columns. • * • / am constructing a 2-slide tuner accord- ing to enclosed sketch. Give me a hook-up for this.— George Cole, Sandusky, O. If you will look in Radio World. No. 11, dated June 10, you will find an article and several hook-ups, "How to Construct Onc- and Two-slide Tuners." by George W. May. You mention using a flat board for your winding core. This is all right, but why not stick to the standard way and wind it on a round tube or core? • » * What sise windings should be used in the regenerative set described by Harold Day in Radio World, No. 30, dated October 21. — Scott Weakby, Kansas City, Kansas. You should use No. 20 wire wound in the following manner: eight turns with taps taken off every turn, then seven groups of eight turns apiece. This will permit you to get what is known as single-turn tuning. The rotor should be wound full with the same size wire. * • • Can a step-down transformer be used to light bulbs? We have D-C current.— John Spigler, New York City. A step-down transformer cannot be used on D C. It will only work on A C. * * • Enclosed find diagram of superheterodyne with 5 tubes. When hooked up. as shown in diagram, J get nothing but hotels. What is the matter? — William Charlman. Potts- ville. Pa. Yotir diagram is correct. A superhetero- dyne is a very hard circuit to manipulate. \V'c suggest that you consult anyone of the following hack numbers of Radio Would in order to learn the correct manipulation of this circuit: June 24, July 8. July IS. August 5, September 16. If yon are not familiar with working sets of this type, it is better to construct a simpler set as tins is an extremely hard set to work unless you understand it thoroughly, which very few people do. « * » / recently purchased a Paraaon rcicn.-r- a'ive set and hove had wonderful results. Kindlv explain whv stations at a distance, like Atlanta and Chicago, seem to no in ami out. I sometimes lose them entirety. — Rob- ert Steingcr. Rockaway Park. N. V. The trouble you are experiencing is com- mon and is known as "fading." This cannot be helped. It is not the fault of your set • • • 1 — Can I use a radiator pipe for a ground? 2 — Is an outside aerial necessary? 3 — Can I use more than one set of phones with a crystal set? A — // so, will I hat e to use two condens- ers across them. — Inquirer, Youngstown, Pa. 1— Yes. A radiator pipe is all right for a ground. A cold-water pipe is better. 2 — No. Reception can be accomplished with wire strung around the room, but it will not function as well as an outside aerial. 3 — Yes. It will cut down the strength of the signals, but not enough to trouble you. 4 — No. One condenser across the phones is all that is necessary. B C M BROADCAST RADIO RECEIVER Mm; poopto lire ta tow How i araoro mm aortal I* lipMalnla. Otbora oajaot to (Mr proaa I— ■ bate* daeasvod hi polaa ul win*, mm* may InM tbatr oMttty to corral* arte wit* oora naipllf Ite— ■ Rllmlaate taooo feotorro by aalae; BOM Radko Froaa Dewier* Bhould writ* B C M RADIO COMPANY TPHLANTI. MICH. my Ommttn tmr RAIN STORES COIf. V ABU BUI OOKDSNSBBB— FIFOS— RBtttT ANCB CNR*. BTC If year ommt oeaafi any. atom Bay*. It! WM Mta KM. Roy To* TRADE 'VAC-SHIELD" MARK "VAC-SHIELDS" bring in DX. This new invention enables you to eliminate any possibility of linking up the magnetic field between tubes and does away with inter-stage coupling and unnecessary noises, thus over- coming stray capacity effects that are always so troublesome and make it so difficult to tune in distant stations. Make reception worth while. Your set should have them. Order today. By mail, postpaid, $1.00. ORANGE RESEARCH LAB. 41 North 16th Street Eaat Orange. N. J. THE ONLY GENUINE AND GUARANTEED "All Wave" Coupler TRADI MARK FLAT AMD BANK WOOKD Wave Length, 150 to 3,000 Meters th* lh*e*> Jerlcra ♦ooibln a* at all YfjIcftTMl***. YaTlornvp.cn t*4 _ u It perform* in am •nmptx-l unit Us* tmttomm of all >w York CHy YOUR NEWSDEALER will deliver RADIO WORLD to your boom, la orator to be an of lottM* RADIO WORLD .ad of not astasia* • einyle Unit, w« au«teot toot you either auaoenbo direct or throuyh dealer at MM a year wants yoon« kuathnf aabacriptioo repraorauui m ta o*rry eotltyo. , lactsry and big buaincee concern tbtuout the country. Send a* yoev aajac a ad addrme Mr tml aantcoktra. RADIO WORLD. WW Broadway, Nco York Oty.

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RADIO WORLD Pruden Reliable Radio Specialties for Good Results! THE name "Pruden" back of stand- ard Radio Equipment is a guar- antee of mechanical excellence, perfection of workmanship and scientific correctness of design. Now, more than ever, when the market is flooded with inferior goods, it pays to buy standard trade marked products. You can pin your faith to "Pruden." Money- back unconditionally if you do not get com- plete satisfaction. Just a few leaders of Pruden Reliable Products shown here that will give you better radio results at no greater cost. Dealers write today for our interesting proposition. FREDERICK H. PRUDEN INCORPORATED "Best" Variable Condensers require one hole only in panel. This feature is absolutely unique with "Best"; all other makes requiring three or more holes. The plates are made of pure aluminum specially prepared to insure straightness, and sol- dered in slotted tubing, assur- ing uniform spacing and elim- inating use of washers. "Bert" Vernier I.lst $1.50 B Plate .0001*5 MFD.. List S.M 11 Plate .OOOtS MFD. .List S.Oe «S Plate .0006 MFD.. Lilt 8.60 41 Plate .001 MFD.. List 4.M 093 Bergen Ave. Jersey Chy, N. J. Phono-Phane Ptnuaut Radio Detector The only fixed radio detector requiring no adjustment. Used in place of crystal or vacuum tube detector. Gives excellent quality of sound without dis- tortion, battery or tube noises. Detects telegraph signals at several thousand miles. De- tects broadcasted music more clearly than vacuum tube de- tector, and requires no ampli- fication where the incoming signal has sufficient strength to actuate the sensitive phones, [deal for use in regenerative circuits. Handsome, substan- tial, suitable for assembly in the finest radio equipment. Guaranteed against" imperfec- tion or faulty opera- tion. List each . $3.50 The De Luxe U. S. Navy Type Radio Receiver List $595.00 TOR IMMEDIATE DELIVERY CHARLES R. ABLETT CO. 199 Fulton St., NEW YORK CITY Best of Its type — must not be con- fused with instruments selling- for from $200 to $300. Highly selec- tive. Will pick np messages, music, lectures, etc., that lower priced In- struments will not hear. This re- ceiver is equipped with binding posts which are normally short circuited Cor 300 to 6,800 meters by which ware lengths up to 23.000 meters may be received by the attachment of loading colls. Capacities ef proper loading' colls for above are: Primary 50; Secondary BO; Tickler SO millihenries. While the receiver Is provided with a "standby" or un- tuned circuit. It also has an nnusnal degree of selectivity. Although pri- marily designed for the more ad- vanced fields of Radio work, or the laboratory, the simplicity of arrange- ment and beauty of finish make it nnusnally desirable for the radt* club or for the Individual who de- sires the finest equipment obtainable for his home or office. In the re- ceiver, Bnkellte tubes, threaded, pro- vide the forms on which Inductance colls of high frequency cable are bank-wound. After assembling, the colls are Impregnated, with an In- sulating compound, In vacuum, and thoroughly baked. The Inductance switch controls a mechanism whereby the different sections may be con- nected, completely disconnected and opened, or completely disconnected and Individually short circuited. This arrangement is Important for, by It, each coll has a natural period when connected which Is leas than the shortest wave length In the re- ceiver's range. The reception of parasitic signals Is overcome, the absorption of desired signals by the colls Is minimised, more energy la forced to the detector and on all wave lengths the Interference la reduced. Digitized by Google

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VOLUME TWO OF RADIO WORLD [Enured u seanod-claas matter, March M. 1KB, at tha Tm t Office at New York, If. Y„ under the act of March J, W1J A Weakly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publication* Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. VoL II, No. 15. Whole No. 41 January 6, 1923 15c per copy, $6.00 a year But You Can't Throw Rice at the Set! Yea, ft Underwood, N. Y.) beard this wedding Idea! The ceremony the extreme left. Next Mies performed at the American , the bride; Mr. Woorra, THE marriage by radio of Miss Margaret Girstner and Joseph Woorm, of New York City, at the American Radio Exposition, held at the Grand Central Palace, was an event that will make radio history. The ceremony, at which Rev. B. F. Saxon officiated, was heard by many thousands of "listeners-in." One of the large exhibitors of the exposition presented the happy couple with a complete receiving set. The manage- ment gave them a wedding breakfast and a gift of money. It is estimated that over half the population of the radio world was "present" at this novel wedding through the courtesy of station WEAF. The happy couple stood on the balcony facing the crowds below, and everv word uttered Dr. Saxon, the offidatfof minister, at groom, and his beet num. was amplified through the special power speech-amplifier so that every person in the exposition could hear. From the exposition these words were transmitted over land wires to WEAF and broadcast over the world. The bride's family, who live out of town, were listening in when the ceremony was performed, which is just as good as being present. Digitized by Google

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4 RADIO WORLD How to Make a Variable Grid-Leak By Ortherus Gordon vkx or »mw«s »WT UNLESS an article on con- struction really helps an ama- teur by showing him, in at least one way, how to improve his apparatus, it fails in its purpose. Scientists and experimenters are finding new faults with present-day radio apparatus and are construct- ing more efficient instruments to re- place those found wanting. The craze seems to be in getting all the elements of radio reception under variable control. But such a craze is madness in the right direction. Radio sets are like children : no two are alike and no two respond to the same treatment. Each requires in- dividual attention and instruments are being manufactured with this idea of "personal service" in view. The latest improvement along this line is a variable grid leak, plans for which accompany this article. Grid leaks were formerly considered an unimportant part of the vacuum- tube receiving set; but not now. Considering the duty of grid leaks and the confusion that results when they fail in their duty, it is a wonder that more attention has not been paid to ways and means of improving them. What is a grid leak, anyway? What is it for? ft- When a vacuum tube is operating at top-notch speed, there piles up on its grid an unwilling swarm of negative electrons. If given the chance, every single electron in this swarm would beat a hasty retreat, leaving the grid empty and the vacuum tube "dead." On the other hand, if no avenue of escape is opened to those electrons which ex- ceed the number properly needed by the grid, the "extras" would "choke" the set and play havoc with decent reception of signals. If a door is opened, everybody goes home; if the door remains closed, there's a riot. There is, however, a way of main- taining the golden average, which, as you already know, is by connect- ing a grid leak to the grid of the vacuum tube. A grid leak is nothing more than a barrier of very high resistance, only broken down when the negative electrons amount to such numbers as to successfully charge and cross it. In other words, the resistance of the grid leak should be high enough to keep back just the amount of electrons needed by the grid. Every grid has different requirements — and a resistance that is "jake" — for one will be too high for another and MtVWI»WTH irtot* mm IT CUT Oft THIK UtUR ©own 16 ' <m co*i»ew ~ TVMCH too low for still a third. Moreover, it has been found that the same grid has various demands when working under a variety of conditions. For this reason, a variable grid leak is an essential to maximum efficiency. The workshop plans for such an instrument, illustrating this article, have been proved by actual con- struction. If followed, the result will be as good a grid leak as can be bought anywhere. The instru- ment is good-looking, may be mounted on a panel in an upright po- sition, or laid down flat on the base- board; and, what is more to the point, it may be built by any ama- teur for a few cents. Because a condenser invariably goes with the grid leak, and the combination termed a "grid-leak condenser," the plans are extended to include a' condenser as well. The capacity of such will be about .00025 mfds., while the resistance of the grid leak will range from practically zero to about four megohms. •ura Z— Diagrammatic aatafla of the frid-Uak. "Condenser packs" is the name I have given the two bakelite, or hard-rubber rectangles, used as blocks about which to construct the grid leak. They are 3 inches long by \y% inches wide and of any thickness over ft of an inch. Wood is hardly recommended unless it is a very hard wood such as ash, oak, or maple soaked in melted wax or some other insulating composition. Even then, it will not be as satisfac- tory as hard rubber, bakelite, or any other composition panel material. The condenser; is a departure, in shape at least, from the ordinary strips of metal or metal foil. The detailed drawing (Figure 3) calls for tin foil, sheet brass, Or copper, cut in the shape and dimensions shown. The plates are on an angle so they will go from one binding post to the other in a diagonal line. The extensions are brought out and Digitized by

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RADIO WORLD 5 To Reclaim Dry Cells By C. C. Huntington, Mauch Chunk, Pa. NOW that the lj^-volt tube is so popular conservation of dry cells is worth con- sidering. Old cells which have outlived their usefulness for ignition purposes, may be reclaimed without trouble or expense and without the use of sloppy mixtures. The reclamation is genuine, not makeshift Connect three old cells: A, B, and C, as shown in the accompanying drawing, and let stand over night In the morning, cell A will show approximately the combined am- perage of the three before connecting. It would be well to select for reclamation the cell showing highest amperage. The beauty of this is that it works. Try it Schematic of the thrao calls bjr Mr. Huntington. (Continued from preceding page) bent around the condenser packs; one in front to the lower binding- post and the other behind to the upper binding-post. The dielectric, or the insulation intervening between the two con- denser plates, is a rectangular piece of mica or heavily waxed paper cut to the same dimensions as the con- denser packs. When the dielectric is made, the condenser unit is as- sembled as shown in Figure 3 ; and, when ready, the two holes are drilled through everything at the same time. Then the bolts from the binding posts are inserted and the condenser packs temporarily tight- ened to await completion of the vari- able grid leak. As shown in Figure 1, the grid leak is mounted on the face of the front condenser pack. The details are given in Figure 2. They com- prise a piece of thick blotting paper soaked with India ink, a slider-rod, and a thin brass slider. The blot- ting paper is, of course, the grid leak itself, while the slider-rod and slider only serve to vary its re- sistance. The India ink mentioned is known as drawing ink. It may be obtained from an amateur friend who has a drawing-outfit, or at any stationery store. In soaking the blotter, it is better to use a large piece and then cut it to size. Tack or pin the paper down to a thin piece of metal so that all the ink poured on it will be absorbed by the blotter. Then let it dry and cut out a rectangle inches long by ^ of an inch wide. Punch a hole in it to correspond with the upper binding post and then stick it, with glue, in the position shown. For this operation, paste will not do. Use glue or household cement. The slider-rod is a piece of brass or copper rod 3 13/16 inches long by }i of an inch wide. Have it thick enough so that the rod will not bend. About 1/16 of an inch should be about right. Bend the rod and drill it as shown; but before putting it in final position on the condenser pack, make the slider. Take a thin piece of spring brass and cut it according to the detail in Figure 2. A sharp chisel will cut out the lug to perfection, so that it can be bent down to clip on the rod. Then bend the whole slider in the shape indicated, put on a knob o"f some kind, and fasten it to the rod. Then put the rod in place, tighten up the bolts, and the job is done. The result is a neat and efficient grid leak condenser, which should drag in those weak signals which are now on the outer edge of your receiving range. When the slider is well to the left, the resistance is very low, but it increases as the **0*T Ficon 4— Alternate sonsstkm which mar appaal to soma amateurs whs want to without a slider is moved slowly to the right. One side of the grid leak is con- nected to the grid, while the other side is connected to the secondary of the tuning device. The positive pole of the A battery is also con- nected to the other end of the sec- ondary, so that the positive side of the battery attracts the negative charge of the grid, drawing it in some degree through the grid leak. Some hook-ups cut out the second- ary from this circuit and show the grid leak connected directly between the positive pole of the A battery and the grid of the tube. Figure 4 suggests an alternate shape of variable grid leak. The blotter is cut into a' semicircular form, and a knob and pointer used instead of a slider. Some amateurs may prefer this plan over the other, but it does not lend itself very read- ily to a combination of both grid leak and condenser. Worth Knowing You Can't— RECEIVE signals if you forget to throw the lightning switch. Expect a tube to work right after letting it fall on a concrete or hard- wood floor. Get the filament of your tube to last if you connect your B battery to it. It will light up brightly for a short space of time, but it doesn't last long enough to produce satis- faction. Besides, you wouldn't be able to get the B-battery connec- tions right. Expect to get Cuba regularly on a crystal set. Hear church services over the radio and get satisfaction. You are generally too comfortable when sit- ting at your set. * * * Let us look at radio in connection with the question of isolation. Think of the condition of most country roads at this time of the year; snow-covered and practically impassable. Think of what radio means to the folks imprisoned in the midst of snow-covered fields. Think of what a force this will be in keep- ing the young folks on the farm, a problem now causing the govern- ment much worry. Radio will not only entertain the farm folks, but it will help to overcome the funda- mental cause of the desertion of rural communities. In connection with isolation, let us not forget the men in the lumber and mining camps and in the lighthouse service. Take the latter, whose lives are dedicated to the safety of travelers. In many cases, radio has relieved the tedium of life on the "lights." For the first time in his- tory, these men can keep in touch with the world that used to pass them by. * * * It sometimes happens that you won't get any results when you hook up a tickler-circuit regenerative set. If this happens, try switching your tickler leads, changing the connec- tions, thereby changing the direc- tion of the current through the cir- cuit. The easiest way to tell whether your tickler is connected is by the rushing sound heard in the phones when the circuit is brought into resonance. If you don't hear this sound, switch your leads. * * * Crystal detectors, no matter how sensitive, cannot be depended on for broadcast reception over a distance of more than 25 miles, although greater distances may be covered under favorable conditions. Code messages may be received over long distances. Digitized by Google

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6 RADIO WORLD New Game for Radio Amateurs By A. G. Shirt FORECASTING the weather by means of a radio receiver is a new game for radio amateurs. It is fully as fascinating, and almost as scientific, as chess. It has an ele- ment of chance, of course; but long practice will give to radio amateurs that weather "instinct" formerly enjoyed only by old salts or people with rheumatics. It does not consist in merely copying government fore- casts sent out by Arlington, after the time signals, at 10 p. m. It is much more interesting. There is not a haggard member of the great radio fraternity who has not had the weather clamp down on his radio activities at one time or another. In fact, the weather occasionally stirs up a rumpus, not for the sake of healthful argument, but because it is its prerogative. So many "big fellows" have been double-crossed by the tyrant weather that an amateur stops to think after telling the story of his own modest DX work and adds, reflectively and significantly: "Under, of course, favorable weather conditions." When he writes about ranges he adds: "U, of course, F W C." Then he jumps all the distances mentioned in his letter by one hundred miles to take care of the DX he would hear on that wonderfully clear night he has been waiting for. The boys understand all this and immediately evolve a prob- lem in mental deduction. Weather is a tribulation ; but it's an ill wind that blows no good, and what gives us a pain in one respect is as good as a tonic in another. If our radio-receiver acts queer when it is cloudy, queerer when it rains, and queerest in a thunder-shower, why not catalogue these symptoms and then turn into the truest little weather prognosticator that ever happened? Why not consult the radio receiver on the eve of some important event, and then place a few odds on the appear- ance or non-appearance of Old Sol? However, enough is already known about how approaching weather affects radio receivers to make fairly decent prophets of us all. Several Westing- house engineers have been studying the matter. While their data is not New Code-Translating Typewriter for Radiotelegraphy or Regular Wire Work by win 1. this nev to Edward Hebem, Oakland, California, ia shown using the machine, which has interest of government official*. The machine, with the wheel Inserted, translates the coded message from any similar immediately upon receipt. An electric current is applied in combinations, which causes the machine at the receiving end reproduce in understandable words an apparently meaningless systematic jumble of syllables sent out by the operator of the machine. The secret of the Invention Is In its master wheel, spool not unlike that on which typewriter ribbons are wound, coi lag twenty-six apertures on either side and a similar number la rim, the whole being three Inches in diameter. Each letter is to but yet complete, they have demonstrated that radio waves are boosted along by high barometric pressures and set down by low barometric pressures. High pressure, as a general rule, in- dicates clear weather; while low pres- sure means bad weather. The graphic illustration of a storm as used by the Weather Bureau is a cluster of concentric circles, with the lowest barometric reading enclosed by the inner circle. This is the heart of the disturbance, or the storm center. Dis- turbances move in two directions at the same time. They twirl about their center in an enlarged cyclonic move- ment, like a top, and also sweep forward over the surface of the earth. They are like a fellow who gets delirium-tremens and then goes visit- ing his wife's relations. In the United States weather matters are quite simplified. Storms take one of two possible directions. They either sweep across country from west to east or they brush up the Atlantic Coast line from south to north. Therefore, a radio receiver situated in the eastern states, or on the Atlantic seaboard, is vulnerable from two points of the compass. If stations to the west are heard faintly, or not at all, it means that, other things being equal, there is a low barometric dis- turbance intervening. The disturbance is moving east. By tuning in on stations nearer the observer's receiver, and determining just where the signals begin to weaken, you can tell the approximate location of the storm. A little practice will enable you to com- pute the hour at which it is due to break in your own locality. The same interesting procedure may be carried out when signals from the south are lacking in their usual in- tensity. If the "Voice of the South" sounds as if it were as far away as Buenos Aires then you may expect something else besides a concert. It does happen, however, that all low-pressure areas are not raging storms, but merely uncomfortable weather. A low barometer coming from the west, for ■ example, means warm, cloudy weather with wind from the east. A high barometer from the west means clear, cold weather with westerly winds. A low barometric pressure sneaking up from the south (and consequently putting a damper on signals from that direction) means wet weather with southerly winds. When the amateur has had a little practice he can tell by the speed with which the low area approaches just how intense a disturbance to expect. Digitized by Google

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RADIO WORLD 7 How 45 Men Were Saved from Death at Sea by Radio Radio Log of Rescue of 45 Men from the S. S. "Monte Grappa" by the White Star Liner "Pittsburgh," on the High Seas. The "Monte Grappa" was bound from Montreal to Trieste, the "Pittsburgh" from New York to Bremen THE radio record of the rescue, at told in the log of the messages which passed between the "Pittsburgh" and the doomed "Monte Grappa" on the night of November 15, 1922, is an eloquent narration of a modern wonder. One feature of the rescue not stressed in published accounts was the nicety whh which Captain Thomas Jones of the "Pittsburgh" laid his course for 185 miles to intercept the sinking "Monte Grappa," whose speed dimin- ished from 8 to 3 knots an hour. It was a masterly piece of judgment, a kind of super-navigation. When the "Monte Grappa" of Trieste, with her cargo of grain shifted, sent out here S. O. S. she was steaming about 8 miles an hour, and her course was North 60 degrees E. The "Pitts- burgh" turned toward her at 16 miles an hour on a course South, 80 degrees E. The courses of the two ships formed two sides of a triangle. Yet Captain Jones calculated bis course and speed so exactly that after running more than 15 hours, in a gale and heavy sea, he was able to intercept the then helpless "Monte Grappa" in the nick of time. Other ships had heard the "Monte Grappa's" call, but none had acted on it with the pre- cision and effectiveness of the "Pittsburgh" : A summary of the"Pittsburgh's" radio log of the rescue follows: At 1.47 a. m., eastern standard time, all shore stations stopped transmitting for the S. O. S. of the "Monte Grappa." At 1.52 a. m., St. Pierre, Newfoundland, was repeating the "Monte Grappa's" posi- tion, lat. 43* 18* N., long. 41° 55' W., and message, "list to port in heavy sea." At 2.10 a. m., Cape Race asked, "Any ship going to assistance of 'Monte Grappa?' " In two minutes the "Pittsburgh" replied, "Our lat 44* 25' N., long. 45° 49* W. Distance from the 'Monte Grappa' 186 miles. Steer- ing for him." Five minutes later the "Monte Grappa" asked the "Pittsburgh," "What is your dis- tance from us?" The "Pittsburgh'' replied, "185 miles, speed 16 knots." One minute later the "Monte Grappa" re- plied, "Our course N. E., speed 8 knots." In another minute the "Pittsburgh" re- plied, "Course, S. 66° E." Any sailor can visualize the relative posi- tion of the ships from this information. Captain Jones was entering on a chase with death that to many men would have been blind man's buff. At 2.44 a. m., the Belle Isle station asked if the "Pittsburgh" was going to the assist- ance of the "Monte Grappa" and was answered in the affirmative. One minute later the American steamer "President Taft" asked the "Pittsburgh" if the "Monte Grappa" wanted immediate as- sistance and answer was given. . A little later the "Mongolia" of the Amer- ican Line and the "Seydlitz," a German ship, received information from the "Pittsburgh" of the "Monte Grappa's" position. The Pace Quickens Long before daylight, as the "Pittsburgh" raced through a rough sea, it became evi- dent that the plight of the "Monte Grappa" By Peter Gray was growing more serious as the night wore on. At 4.03 a. m., she sent a more urgent ap- peal to the "Pittsburgh." It was "Please stand by." This was followed at 426 a. m., by the message, "We require immediately one of the boats to come alongside." At 4.56 a. m., the "Pittsburgh" again checked up the "Monte Grappa's" position by asking "What is your course?" The answer was "Wait." This was not reassuring. Three minutes later the "Monte Grappa" was asked the same question and gave the same answer. In another three minutes the required facts came through. "Our course N. 55" E., speed 5 miles." It will be noticed that the speed of the "Monte Grappa" had lessened three knots, and this made the problem of Captain Jones increas- ingly difficult At 5.22 a. m., Captain Jones gave the "Monte Grappa" his position and speed, adding "Can you steam toward us?" The answer was, "Impossible to steer toward you. Be alongside as soon as possible." The "Seydlitz" also was steaming toward the "Monte Grappa," but at 626 a. m., on learning of the "Pittsburgh's" progress, she resumed her course for the English Chan- nel. At 8.34 a. m., the steamship "Lackawanna" Pamphlet on Coil at Nominal Cost THERE has appeared Bureau of Stand- ards Scientific Paper No. 455, Tables for the Calculation of the Inductance of Cir- cular Coils of Rectangular Cross Section, by Frederick W. Grover. This paper gives tables which have been carefully calculated, by means of which the inductance of multi- layer coils may be quickly and accurately computed by the simplest of arithmetical operations. The tabulated values in the tables are correct to 1 part in 10,000. The necessity for long and tedious computations directly from the complicated formulas and for selecting the most suitable formula for a given case are thus avoided. The formulas on which the tables are based are collected for reference, and the theoretical problems involved and the limitations of each formula are discussed. Examples are given to illus- trate and explain the use of the tables. The calculation of mutual inductance for certain cases of multilayer coils is treated. This paper should be regarded as supplementary to Bureau of Standards Scientific Paper No. 169, Formulas and Tables for Calculation of Mutual and Self-Inductance, which covers many different kinds of inductance coils. A copy of Scientific Paper No. 455 may be purchased for 10 cents from the Superin- tendent of Documents, Government Printing Office. Washington, D. C. asked the "Monte Grappa, "Do you need any assistance?" to which the "Monte Grappa" replied, "It is already coming— 'Pittsburgh.'" Captain Jones periodically checked up the "Monte Grappa's" speed and course. At 10.39 a. m., he sent the message, If you carry the same course and speed we ought to be up with you by 7.00 tonight" Captain Jones' faith in his abiltiy to reach the "Monte Grappa," if she kept afloat, is shown in this message, sent at 323 p. m.. from the "Pittsburgh" : "At 8.30 Greenwich mean time will you please send up a rocket and repeat every fifteen minutes. How many peo- ple have you on board ? Compliments." The answer of the "Monte Grappa" gave Captain Jones the measure of the job he had before him. It was, "Will send up rockets. Have 45 men on board. Very likely will be obliged to abandon ship. I have no lifeboats." Closing In At 4.00 p. m., the "Monte Grappa" asked the "Pittsburgh," "Do you see our rockets?" The answer was "No." Twenty minutes later the "Pittsburgh- flashed a message that must have been among the most joyful the captain of the "Monte Grappa" ever received. It was, "We have seen your rockets and are bearing down on you." To this the answer was "O. K." In another twenty minutes the "Monte Grappa" reported, "Now we will send up another rocket. Let me know if you see it Seven minutes later she asked, "When do you expect to be alongside?" The "Pittsburgh" replied, "Steaming for you 16 knots; can you see our masthead lights?' The answer was "Cannot." < At 5.26 p. m., the "Pittsburgh" asked the 'Monte Grappa," "How is the sea alongside of you?" "On starboard side quiet; that is, not breaking," was the answer. At 6.05 p. m., the "Monte Grappa" re- ported, "Must abandon ship." To this the "Pittsburgh" responded, "Will take yon off right away." There was an interchange of messages as to the number of boats to be sent. Then these messages were exchanged: "Pittsburgh" : "Stop your ship." "Monte Grappa": "We are stopped." "Pittsburgh' : "Sending two boats to star- board side.' "Monte Grappa" "When your boats leave give long whistle." "Pittsburgh": "Yes." At 6.34 p. m., the "Pittsburgh" sent the message, "Boat now coming." An hour and 12 minutes passed before a message came from the "Monte Grappa" saying, "A boat now coming." The "Pittsburgh" then answered, "Second boat Just left for you." It was 9.39 p. m., when the "Pittsburgh's" radio operator made this entry in his log- "Crew of 'Monte Grappa' all rescued and aboard. AH 'Pittsburgh's* boats back. Re- sumed normal watch." The closing entry in the "Pittsburgh's" radio record of the day was: "10.25 p. m. broadcast derelict warnings to all stations." Digitized by Google

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RADIO WORLD Get Radio Goods That Stand the Test By C. White, Consulting Engineer LACK of knowledge, or, per- haps, neglect of certain fun- damental points is frequently a source of multifold trouble. It is a shame that any results are obtain- able with poorly constructed ap- paratus. If such were the case, only the better grade of goods would be placed on the market. But, never- theless, the great educational work that radio journals are carrying on is sure to result in the eventual blacklisting of all manufacturers who refuse to let quality be their standard. The radio manufacturer is just like the rest of us; he is human, subject to error, and by no means infallible in judgment. Hence, we must not be too severe and must consider that the vast majority are in the radio game to stay and are doing the best to improve the field. What is really needed is con- structive, not destructive, criticism. It is only by the general getting to- gether of amateurs, professionals, and manufacturers that standardiza- tion and many other desired im- provements will be forth coming. National Radio Week is just the thing to bring such facts to light. As an example of neglect, let me first bring to light the phones used in radio reception. There has been, perhaps, no other article of the radio trade that has suffered so much as the telephones. The fact that they are outwardly easy to make has at- tracted many although their knowl- edge is rather limited. The principle of the radio, or, in fact, any tele- phone receiver is that of the electro- magnet. The feeble signal-current passing through the coils of wire in the phones causes the diaphram to be moved backward and forward in rapid succession, thereby trans- lating electrical impulses of the re- ceived current into corresponding sound waves. The volume of the sound emitted depends on the strength of the electromagnets. Fundamental electrical engineering tells us that the strength of any electromagnet is a direct function of the number of turns of wire on the magnet and the current flowing through these turns — in technical language, the number of ampere- turns (the ampere being the measure of electrical current). Since in a radio or telephone cir- cuit the actual current flowing is ex- ceedingly small, hence to get a fairly strong magnet we must place a larger number of turns than would be necessary if the current were greater in value. To do this and still keep the size of the coil within the limits of the space available within the receiver piece, we must resort to the use of extremely fine wire. Now, since the number of turns is many and the size small, we have grown accustomed to rate a receiver in terms of the resistance of the coils instead of the ampere turns, which would have been the logical and more scientific thing to have done. But, so long as we kept to one kind of wire, (copper), we were strictly safe in so doing be- cause the resistance was a measure of the relative ampere turns. Nat- urally, a pair of phones rated at 3,000 ohms was looked on as superior in every way to a pair rated at 1,500. This was O. K. until some dis- Aerial Atop Clothesline Pole ■ // s \J r Nord wrial araeted by J. O. Walah, Bayaana, New JefMjr. IN response to Radio World's call to amateurs and fans to send in for pub- lication any radio stunt, experiment, or hook-up they may have found useful and which they would like to share with others, J. O. Walsh, 10 West 16th Street, Bayonne, New Jersey, contributes a pho- tograph of his loop aerial set on top of a clothesline pole. Mr. Walsh states that he is "getting good work" from WEAF, WJZ and WOR on a small outfit which cost only $12. honest manufacturers deliberately wound German silver wire on their phones in order to raise their ohmic resistance. Since German silver has more resistance per unit length of the same cross-sectional area than copper, it was perfectly true that a few turns of it would give a resist- ance many times greater than many turns of the same size of cop- per wire. But how about the num- ber of ampere turns? The manu- facturer was either ignorant of the fact that the basic fact underlying good phone-design was ampere turns and not the indirect measure of ampere turns, resistance, that is desirable; or, he was trying to rely on the fact that the average radio- man thinks of phones in terms of their resistance. Such deception can not last long, especially when amateurs are learning to ask for the better make of apparatus. Some, no doubt, are aware of the fact that certain makes of phones are better than certain other makes regardless of the resistance ratings. While the number of ampere turns is the fundamental determin- ing factor in phone design, there are other minor considerations which play a large part in the value of the instrument. A pair of phones used for radiophone reception should have a resonant point at about 870 cycles. This is much desired because telephone engi- neers have proved that the average electrical value of the human voice is 870 cycles, although the range of human sound vibrations varies from 200 to 2,200 cycles. Extensive ex- periments have so definitely verified this fact, that telephone receivers are all made to have, or give, the maximum response at about 870 cycles. A radio receiver made for voice reception should not only give the maximum response at that fre- quency, but, also, be capable of re- producing the higher-voice fre- quencies with the minimum amount of distortion. In addition, a good pair of phones must use good steel in its magnetic circuit in order to keep the magnetic energy losses as low as possible. Regarding the basic facts that amateurs commonly abuse: Vacuum tubes are delicate, scientific in- struments and their behavior, or characteristics, vary greatly accord- ing to the type of the tube — and the manufacturer. We may list tubes, first, according to hardness; and, second, according to make. A care- Digitized by Google

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RADIO WORLD 9 Too Much Tuning By Jack Turner Radio Editor, "The Age-Herald," Birmingham, Ala. MANY who listen in on the broadcast programs have a habit of changing from one station to another. The following is about the way it comes out of the loud-speaker when the "tuning hound*' is "at the wheel": "This is WWJ, the radiophone broadcasting station of the," — "Island where Robinson Crusoe and his good man, Friday, stayed." — "The first selection from the Fort Worth Star-Telegram,"— "located in Cincinnati, Ohio, — "will be a vocal solo/*— "played by Paul Whiteman and his orchestra." — "The radio- phone broadcasting station of the Sweeney" — "School of Chiroprac- tic,"—"Jefferson City, Missouri,"— "will next entertain the little listen- ers with a bedtime story. Now all you little boys, and all you little girls, too. To-night, I am going to tell you about,"— "Senoras y cabal- leros. Fatima dietes malachrino portina ramases La Entrado nurica. Este es Habana, Cuba."— "Absolute- ly, Mr. Gallagher; positively, Mr. Shean!"— "The whole congregation (Continued from preceding page) fully designed radio-circuit may function wonderfully with a Radio- tron of the U-V 200 type and still the performance of the same circuit with another make of tube might be very disappointing. You can not take a circuit that is designed for a hard tube and expect it to function perfectly with a soft tube even of the same manufacture. Amateurs in general think that a vacuum tube is a vacuum tube and that classifica- tion is unnecessary. Some, no doubt, go a step further and class them as soft, medium, and hard; but, few take the trouble to actually differentiate between the relative advantages and disadvantages of certain makes in various circuits. The recent release of the WD-11 tube for general amateur work will cause many manufacturers to use it in circuits where it cannot be ad- vantageously applied. The fact that it is lighted from a small dry cell is a most advantageous asset; but there are other points to be consid- ered before its application. From recent laboratory reports it does not function very well in radio-fre- quency and superregenerative cir- cuits, but it is very satisfactory in the average simple, or regenerative, will now please stand and sing Hymn No. 294,"— "Kiss Mamma, Kiss Papa." — "The service will be continued by reading the scripture," — "McNoot is groggy. The battle won't last much longer at this rate. He goes down for the count I One- two-three-four-five-six-seven-eight- nine," — "Ten o'clock, Central Stand- ard time."— "The final results are," — "lost and any reports on this car will be greatly appreciated." — "As it is now," — "Three o'clock in the morning," — "We will relay the Ar- lington time signal." — "We take pleasure in introducing to our un- seen audience Mr. Bluelaw. He will speak representing the Anti-Dance League. Mr. Bluelaw, ladies and gentlemen — " — "The next number by The Jelly Jazz Hounds' Orches- tra will be, *Nobody Lied.' "—"The market reports as given us by the," — "Woman's. Aid. Society of this city, are as follows," — ''Shelby County. A still was captured here to-day, after a hard battle between the," — "Ministers here."— "The next num- ber from the Milwaukee station will receiver. Before using any tube in your circuit be sure that is the most efficient for that type of circuit. Many mediocre results obtained are blamed on sets and circuits, where the real blame should be placed on the employment of the wrong type of vacuum bulb. It is a good plan to be logical, scientific, and consistent. One of the most inconsistent practices is the use of heavy insulators on the antennae supports, but the lead-in wire is allowed to rub, or touch, the roof and the sides of the house with- out any insulation. Another bad practice is that of poorly grounding a set on a radiator. A good ground is often more essential to reception than an aerial Another mistake is the belief that a double-wire aerial 50 feet long is equal to a single-wire aerial 100 feet long. The latter is far more efficient. It is well for the novice to try out aerials of different lengths. Sometimes very startling results may be obtained by length- ening and shortening an aerial. With a short aerial, it is generally much more difficult to tune. You will soon find that by experimenting that many items that you had hitherto regarded as very common- place mean an efficient outfit. be a solo, 'Drink to Me Only With Thine Eyes."— "Dah Dee Dah Dee, Dah Dah Dee Dah."— "As the pro- fessor has promised to make a speech,"— "We will sign off."— "Good Night !" Radio Plays Leading Part in Municipal Work

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10 RADIO WORLD The Radio Primer • For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks Why Multilayer Coils Are Used in Radio Work J J T HAT is the function of an mA/ antenna? F r To radiate energy in the form of electromagnetic waves, or to absorb' part of the energy radiated from a distant transmitter. * * * Name two types of aerials in com- mon use. The inverted L and the T aerial. * * * What general effect has the height of an aerial on the range of a station? Usually the higher the aerial the greater the range. This does not apply in all cases. * * * Define the fundamental wave length of an aerial. The wave radiated by an oscillatory circuit consisting of merely an aerial and ground is called the natural wave length. * * * What will be the effect on the range of the station if the insulation of an aerial is poor? If an aerial is not efficiently in- sulated it considerably decreases the range of the station, if it does not render it entirely inoperative. * * * What is the function of a loose- coupler in a receiver? The loose-coupler in a receiving cir- cuit provides a means of tuning the open and closed circuits; also a means of transferring the energy from the antenna circuit to the local detector- circuit * * * What is the effect of tightening the coupling in a receiving circuit? It makes the circuit responsive to a wide range of wave lengths without delicate adjustment of the tuning ele- ments because it increases the damp- ing of the receiving circuit. * * * What is the advantage of having the coupling of a receiving transformer variable? It enables one to tune his receiver "sharply," thereby eliminating inter- ference from undesired stations. This is due to the fact that each transmitter has a different degree of damping. * * * How could signals be received the wave length of which is shorter than the natural wave length of the receiv- ing antenna? By inserting a variable condenser in series with the antenna circuit. * * * What is the use of a variable con- denser in parallel with the secondary of a receiving transformer? The variable condenser in shunt (parallel) of the secondary of the re- ceiving set serves to add capacity to the circuit and permits a finer degree of tuning of the secondary circuit than could be obtained by only varying the value of the inductance or the coupling. * * * Why arc the windings of head tele- phones of high resistance? The magnetizing force of any cur- rent-carrying coil depends on the number of ampere turns. Thus, to get the loudest response in a phone from very weak currents, it is necessary to use hundreds of turns of wire. Due to the fact that the coils cannot take up much space very fine wire is used. As we know, the smaller the size of the wire the greater the resistance. This accounts for the fact that all sensitive telephones are of very high resistance. Remember that it is not the resistance of the telephones that account for their sensitiveness, but the great number of ampere turns wound on the spools, which make the resistance high. * * * What are the names of some of the more common crystal detectors? Galena, Silicon, Perikon, Ferron, Cerusite. * * * How do you adjust a crystal detector to its maximum degree of sensitive- ness? Set the test buzzer into operation and alternately place the cat whisker on various points of the crystal's sur- face until the loudest response is given in the telephones. * * * What is the purpose of a crystal detector in a receiving circuit? A crystal detector is used to convert the incoming radio-frequency into a direct current that is audible in the telephone receivers by only allowing the current to flow in one direction through the circuit. I N radio apparatus, coils of more than one _ layer, or multiple-layer coils, are fre- quently used, particularly when it is desired to obtain a coil of comparatively large in- ductance in a small space. Multilayer coil» are also used in many other fields of electri- cal work. A simple form of multilayer coil is wound layer on layer in a channel of rectangular cross section. Coils of this type are useful in low-frequency work. Multi- layer coils of. this simple type, however, have a very considerable capacity between layers and are, therefore, not suitable for radio work in which the capacity of coils must be kept low. To reduce this capacity, means must be found either to reduce the potential between adjacent turns in different layersor to increase the distance between layers. The first method is employed in coils prepared with a banked winding, in which the wire is so carried as to achieve the winding of several layers simultaneously. For the method of increasing the distance between layers it is found that a small separation be- tween wires brings about a very appreciable reduction of capacity, but beyond a moder- ate separation little is gained. In one type of coil adjacent layers are separated by thin pieces of insulation of perhaps 1 or 2 milli- meters in thickness. In a type of coil known as "honeycomb" the wire is carried diag- onally back and forth across the cross sec- tion while it is being wound, with the result that wires which run parallel to one another are separated by at least twice the diameter of the covered wire. In the design of elec- trical apparatus, and particularly radio ap- paratus, it is important to be able to cal- culate the inductance of the various types of multilayer coils. Formulas for the inductance of simple types of multilayer coils have been derived by a number of scientists. It is also found that for the bank-wound, "honeycomb," and similar low-capacity windings used in radio work the same formulas apply as for a simple circular coil of rectangular cross sec- tion, provided that an appropriate correction be made for the space occupied by the insu- lation. The formulas are, however, compli- cated, and for any given case the necessary computation is tedious. Furthermore, there are a number of different formulas, some of which are most accurate for short coils, others for long coils or other particular types of coils, so that the engineer may find it difficult to select the formula which is best suited to his particular problem. If many calculations have to be made, some means of reducing the labor of computation and avoiding the difficulty of selecting the most suitable formula is a practical necessity. Such aids which have, heretofore, appeared have taken the form of a single empirical formula to cover the whole range of types of coils or of charts from which the in- ductance, or some function simply related to the inductance, can be interpolated. These methods do not allow of any accuracy great- er than about 1 per cent at best, and in some instances the curves have been based upon unsuitable formulas and give only a rough degree of accuracy. 52 Weeks for ttJt Complete Your File of RADIO WORLD Copies of Radio World No. 1 If you did not get a copy of Radio World No. 1, send us $6.00 and we will send you this paper for one year, and jtart it with our first issue, which will be mailed you as soon as possible after re- ceipt of order. T Digitized by Google

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RADIO WORLD 11 New American Radio Station Will Operate to Southward ANOTHER ethereal link is be- ing forged into the chain of radio stations on the coasts of the United States connecting this country with foreign lands. The new link will couple the United States with South America, the West Indies, and shipping in the South Atlantic Ocean, a section of the world not in direct contact with American stations, until recently, but where radio is rapidly expand- ing. Arrangements have just been made by the Tropical Radio Com- pany for the purchase of land and the erection of a powerful radio- telegraph station at Hialeah, near Miami, Florida. Within about 18 months, Mr. G. M. Davis, of the ra- dio company, promises the public the use of one of the largest radio stations in this country, the esti- mated cost of which is approximate- ly $200,000. Later on, Hialeah will also be equipped with radiophone apparatus. Already the company is handling radio business off the coast, operat- ing on 3 kilowatts from the old Mar- coni Station at Miami Beach, re- cently leased from the Navy Depart- ment, and licensed WAX by the De- partment of Commerce a few days ago. The location of the station on the long arm of Florida, which projects several hundred miles far- ther towards the southern continent than any other point in the States, is believed an ideal location of han- dling radio traffic in that direction. Hialeah'* Equipment the Latest Situated on a plot of ground cov- ering 90 acres, two 437-foot trans- mitting towers, located about 1,000 feet apart, will soon be erected to hold aloft the great transmitting aerials. Apparatus of the latest type, including the new Langmuir 200-kilowatt tubes, is being built by the General Electric Company. To avoid interference, the receiv- ing apparatus will be located in a building live or six miles from the transmitting plant. Three antennae, reaching out in different directions from half a mile to two and a half miles in length, will be erected to catch the long-distance messages from the South. These receiving aerials are of the low-lying type, being erected on forty-foot poles. In the receiving station itself, sev- By IV. R. Service eral Pickard loops to aid operators in reception and eliminate direc- tional interference, will be installed. Operation at the station is to be under the direction of R. G. Mac- kenzie, who will have a crew of about twelve men. Scope of Traffic and Extension Prospects for traffic with Central American and far distant Southern stations are good. The United Fruit Company is now building radio sta- tions in practically all South Amer- ican countries. A week ago, their new station at Tegucigalta, Hon- duras, established radio communica- tion for the first time with the United States with a message to President Harding. Next year, an- other large station at Nicaragua will be opened, it is reported. Within a year, the United Fruit Company's ships will be equipped with radiotelephone apparatus as well as telegraph sets. Recently radio engineers of the company suc- ceeded in telephoning by radio be- tween their New Orleans station and a station at Almirante, Pan- ama. Regular radiotelegraphic com- munication has been maintained be- tween this country and stations in Central America since 1904, but it was eighteen years before a radio- telephone message was transmitted. Extension Teaching by Radio National Radio Chamber of Commerce Asks Educa- tional Institutions to Co-operate in a Working Plan By Tresham D. Gregg Of Gregg & Gregg, Engineers and Managers, National Radio Chamber of Commerce THE importance of radio broadcasting as a means of reaching a large number of people in the United States, otherwise in- accessible, is being forced home to us every day. There are, in the United States, al- most 1,500,000 radio receivers, representing between three and four million radio listen- ers located within comfortable range of the speaker's voice of one of six hundred broad- casting stations — that is, stations equipped to send out telephonic communications. These listeners are for the most part youth- ful— of school and college age. Their num- ber is rapidly increasing and will undoubt- edly, within a very few years, total many millions of radio listeners. The National Radio Chamber of Com- merce appreciates the tremendous potentiali- ties of this new channel of communication in the field of education and desires in some practical way to support colleges and uni- versities in extending their influence through radio-extension courses to these listeners, a large proportion of whom would not otherwise be reached. Several prominent institutions of learning in the United States have made a beginning in this direction, and their reports of the encouraging success at- tending their efforts indicate that the possi- bilities of the new method are not under- estimated. Sixty other educational institutions are broadcasting educational and musical pro-, grams, forty-seven of them being colleges and universities. The combined area nomi- nally covered by these institutions has been estimated to be seven or eight times the total area of the United States. England and Germany have quickly grasp- ed the significance of radiotelephony as a means of educational contact and prepara- tions are being made to broadcast university extension courses in those countries. Extension lectures may be broadcast from the college or university without interfering in any way with the local audience in the school It is not now necessary that the school have is own broadcasting station. It may use a powerful central station, nearby, connected by the microphone in the lecture room. In some instances, the lectures are being followed up by questionnaires and suggested reading which are mailed to the listeners on request, examination sheets fol- lowing at the end of the course. The pioneers are already active in the field and the situation seems to indicate not only individual but concerted action on the part of schools of recognized standing to take advantage of this wonderful oppor- tunity. There are, however, a great many intricate problems connected with the subject of broadcasting which the National Radio Chamber of Commerce hopes to see solved within a comparatively short time. These problems have an intimate connection with the success of any considerable program of educational extension by radio. The engineers of the National Radio Chamber of Commerce have collected much data which it will cheerfully place at the disposal of those educational institutions interested. It will be glad to render every possible assistance to them in reaching a clear understanding of the situation as its only interest in the radio field is to see that radio broadcasting assumes, in the course of its evolution, a sound economic position o* the greatest possible usefulness. Digitized by Google

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It RADIO WORLD Urges Enactment of Radio Bill Secretary Hoover, After Working Out Many National Problems, Starts in Earnest to Clear the Ether of Radio Interference WASHINGTON, D. C— Her- bert R. Hoover, Secretary of Commerce, is ready to start serious consideration by Con- gress of the pending radio legisla- tion. Literally, the final passage of the White Bill, seeking to relocate radio waves, minimize interference and provide for the adequate regula- tion of national radio transmission, will be acclaimed by every amateur. The bills presented in both the Senate and House last June lay dor- mant at the Capitol until Secretary Hoover returned from a protracted trip to the West Coast where he was busy with another national project. Immediately upon his re- turn, he took up the question of the desired radio legislation with Rep- resentative W. H. White, Jr., of Maine, the House champion of ra- dio, and author of the White Bill, with the result that it has been an- nounced that hearings will start be- By Cafl H. Butman fore the House Merchant Marine and Fisheries Committee without further delay. Public Hearing* on White BUI Action is confined to the White Bill, designated as HR-11,964. Hear- ings will be presided over by Rep- resentative W. S. Greene of Massa- chusetts, chairman of the commit- tee, assisted by Mr. White, who is chairman of the subcommittee on radio. The general public is invited to the hearing, and representatives of amateurs, manufacturers, com- mercial companies, broadcasters and even listeners-in are invited to ap- pear with recommendations or ob- jections to the proposed law. Sec- retary Hoover will be present, ac- companied by his radio aides, and some Naval experts also plan to at- tend. The principal recommenda- Hears Pittsburgh and Schenectady on Crystal Set Using a Loop Aerial (C Kadel ft Herbert) Do—n't It make you ead whan, after paying a big price for a radio est, you find that you can hoar only the local station*? Then you bear of a radio fan with a cheap crystal set who picks up the distant stations. It sure does! But when you hear that this same fan gets these results on his crystal set with a loop aerial, you (at a real thrill! Maurice Wald tried a loop aerial on his crystal Just to ass what would happen, and found that he could pick up Pittsburgh and Schenectady, The met that his home is located on one of the highest pieces of ground on Manhattan Island probably accounts for his unusual results. The photograph shows Maurice Wald with his crystal set and loop aerial. tions of the radio conference are in- corporated in the present bill, but the public is now given an oppor- tunity for a last word. Bill Aims to Aid Radio Development In general, the bill is intended to make for the future development' of radio in this country on a purely American basis. It is planned also to clothe the Secretary of Com- merce with sufficient authority that he may control the expansion, op- eration, licensing, and revocation of licenses. A redistribution of wave bands is scheduled in an effort to clear the radio "atmosphere" of un- necessary interference. Among the provisions of the bill is the granting of authority to the Secretary of Commerce to classify transmission stations, designate the service, and assign wave bands. More definite regulatory powers for the Secretary of Commerce are also sought, especially with regard to decreasing interference. Whether or not licenses must be issued re- gardless of that officer's discretion is also to be decided. The existing law of 1912 is silent on many phases of the duties developing upon the Department of Commerce to-day, with thousands of stations in opera- tion ; neither are time limits for the duration of licenses specified. Gov- ernmental authority is doubtful where the revocation of licenses is concerned but the new bill grants such power to the Secretary. Legislation Doe* Not Affect Receiving No regulations are planned for receiving stations, the whole bill be- ing devoted to the transmission of all radio messages and broadcasts. The status of the amateur and the listener-in established by the pres- ent law is left unchanged, except that the rights of the amateur are extended and additional wave lengths are assigned for his use. Much is left to the discretion of the head of the Commerce Department, as it is believed that radio has a future which may be jeopardized if too stringent and detailed regula- tions are enacted into a law. Regu- lations believed just and necessary to-day, under some circumstances, might prove a handicap to the nat- ural development of radio within a space of a few months and hence broad powers are planned for the Secretary of Commerce and his ad- visory committee of twelve mem- bers. Digitized by Google

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RADIO WORLD 13 New and Unusual Circuit for Radio Experimenters By C, White, Consulting Engineer IT is a general belief that we must have some very definite means of coupling to make a vacuum tube oscillate; but such is not al- ways the case. In the strict theoret- ical sense of the word, "coupling," we must have some method of ac- complishing this; but so far as the physical aspect of the circuit is con- cerned, we can make a tube oscil- late with apparently no method of coupling. This trick in the circuit illustrated herewith lies in the fact that, at a casual glance, the eye is deceived in observing that quite a new idea is presented. For those of my readers who are quite experi- mentally inclined, I heartily recom- mend this circuit for testing pur- poses; for, no doubt, they will be very much surprised at the ease with which it will oscillate once the correct value of grid leak and grid- leak condenser is found. The correct constants for the grid leak and its condenser, naturally, are solely dependent on the charac- teristics of the tube used. With a soft tube more trouble will be en- countered than with a hard tube, owing to the fact that the former is frequently quite erratic when used in a circuit of this nature. Analyze this circuit in detail and see wherein it differs from the or- dinary. So far as the tuning ele- ment is concerned, it is nothing more than a single-circuit tuner, consisting of a honeycomb coil whose size depends upon the de- sired wave-length reception, and common 23-plate air variable-con- denser. The detecting circuit is, however, rather different from the ordinary circuit used with the single- circuit tuner in that the grid and filament of the tube are placed across the condenser instead of the tuning inductance. But this is per- fectly permissible since there is a voltage across both when the signal current of the incoming wave is passing in the antennae ground-cir- cuit. It will be noted that the grid leak is not shunted around the grid- leak condenser as usual, but is placed directly from grid to filament. The reason for this is that since we are taking our voltage across the 23- plate condenser instead of the honeycomb coil, the resistance of the condenser is very large in com- parison to that of the leak, hence the total resistance of the actual ! tha circuit hriM by Mr. path from the grid to the filament would be many times that of the leak resistance inserted. By placing the leak, as shown, the resistance of the leak path is just about the same as that of the leak used provided perfect condensers are employed — that is, condensers that have a very high leakage resistance. The phone circuit is in no way different from the ordinary nonre- generative plate-filament circuit. Up to this point, there is really no rad- ical departure from that of an or- dinary simple single nonregenera- tive receiver; but the connection from the plate to the top inductance terminal is quite out of the usual. This connection affords a by-pass for current to the grid and the fila- ment ; and by the choice of the right size capacity for the grid leak, the coupling between the grid and the plate may be adjusted, electrostat- ically, to the correct value to make the tube oscillate within the desired range. Although this circuit, on first sight, seems to have no method of coupling, on careful analysis it obtains its coupling by the employ- ment of the tuning inductance for a double purpose. When carefully made and adjust- ed, this circuit represents one of the most inexpensive single circuits, using a vacuum tube, that can be constructed. Since it will oscillate with ease over its entire scale when once adjusted, it is a very efficient receiver for C-W work. But, owing to the nature of the adjustments that must be first made, I do not recommend this circuit to the novice with little or no experience iri con- structing oscillatory circuits. For the radio experimenter, this hook- up will prove to be very interesting. A good method of finding the right size grid-leak condenser it to insert a number of small mica condensers in parallel until the right amount of capacity is obtained. The grid leak resistance may be found by drawing a few lines with lead pencil over a strip of paper between the two ter- minal points or by employing any other of the well-known modifica- tions of this method. Perhaps with a little care and experimenting, a very efficient circuit may be devel- oped readily from this one. Seven New Broadcasters TOURING the past week, the Depart- xv ment of Commerce licemed seven radio stations for broadcasting" on 360 meters. The new stations are: WPAS— J. & M. Electric Co., Amster- dam, N. Y. WPAP— Theodore D. Phillips, Win- chester, Ky. WPAQ— General Sales & Engineering Co., Frostburg, Md. WPAU— Concordia College, Moor- head, Minn. WWAD— Wright & Wright, Inc., Phil- adelphia. KFEP— Radio Equipment Co., Denver, Colo. KFHJ— Fallon Co., Santa Barbara, Calif. to the 360-wave. The Department of Commerce has just reliceased WHAS, "The Courier-Journal,'* Louisville, Ken- tucky, on 360 meters. This publication believes the 360-meter wave is better suited for its broadcasting, and more popular with the fans. Radio Gives Mariners Aid ThE Mexican Government inaugu- rated a new broadcasting service for mariners on November 1. The service comprises the picking up and rebroad- casting of notices to mariners emanating Jrom radio stations in America, Cuba, and vessels within their cone, by six Mexi- can stations on both the Pacific and Gulf Coasts. "Courier-Journal" Returns to 360 Meters f \ NE big broadcasting station after trying out the Class-B license on 400 meters for a short time, has returned Scheveningen Radio Station I *HE Government of the Netherlands x is enlarging the present radio station at Scheveningen, which soon will be ready for operation. It is designed to communicate with all parts of Europe. Digitized by Google

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u RADIO WORLD Radiograms The Latest Important Radio News Briefly Told for the Growing Army of Radio Fans THE inauguration of an ocean radio-Utter aerrice on United State* Shipping Board tmmIi is announced. Messages from a ship bound in one direction are to be transmitted by radio to a ship bound in another direction, for mailing, when the receiving ship arrives at her destination. The rate for this service will be $120 for twenty words, including registration. Each addi- tional word will cost four cents. Messages are limited to 100 words. * * * Radio has ended the isolation of ono of the most lonely, if ■Met beautiful, spots on earth. Pitcairn Island, storied spot in the South Sea Islands, whose residents have been forced to depend on news brought ,by occasional ships, has a complete radio plant. Visitors to the island, it is reported, brought a set with them, sold it to the natives, and taught a number of the young islanders radio reception and the Morse Code. ♦ ♦ * Beginning December 20 weather broadcasts now transmitted from the United States naval radio station at Miami, FUu, were transferred to the naval station at Jupiter, Fla. (NAQ). The weather will be broadcasted at 11:30 a. m. and 6 p. m. (seventy- fifth meridian time). Hurricane warnings will be broadcasted when issued and repeated at two-hour intervals until midnight. The transmission will be by spark on a wave length of 1,688 meters. • * » David Lloyd George, former Prime Minister of Great Britain, recently journeyed to Algedras, Morocco, for a rest. Be that as it may, his first request was for a powerful radio-receiving set so he could keep in touch with European capitals. • • * Call letters KFOG hare been assigned to all ice patrol vessels of the North Atlantic International lee Patrol. Any vessel de- siring to communicate with the vessel on patrol regarding condi- tions in the ice fields should use the above-mentioned signal. • e * Experimental stations should, as far as possible, avoid using a radiating antenna for testing while other stations in the vicin- ity, including broadcasting stations, are operating. The early morning hours are probably best suited for testing. • * • The amateur radio station operated by Leon Deloy, at Nice, Franco, has boon heard by Gene E. Witham, of Brooklyn. This is the first French amateur station heard by American amateurs. Gene E. Witham, of 126 Eigthy-sixth street, Brooklyn, said that he was listening in on his wireless about 9:30 December 27 when he heard the word "test" repeated several times. It came in faintly in the Morse Code. There followed several French words which he could not understand. The sender then signed off with "8AB." Realizing that this was the signature of the night operator at Nice, France, Witham immediately sent a night letter to the American Radio Relay League at Hartford, telling of his experience. Witham is sixteen years old, and is a student at the Stuyvesant High School. He has a single-bulb detector instrument. Radio Installed Patrol Wagon of Philadelphia Police (C P. * A. Photos) Interior of the Radio- Equipped Police Truck THE Philadelphia Police Depart- ment patrol-wagons keep in constant touch with headquarters by radio. Some time ago, this idea was tried out in the City of Brotherly Love, and it was such a success that now all the patrol wagons are equipped with sets. By referring to the photograph the actual installa- tion may be seen. It is both a trans- mitter and receiver. Lieutenant Harry Edwards is photographed at the set. The set is operated on a loop installed on the top. This opens an entirely new field for radio, and it is only a matter of time when all police trucks in the large cities will be equipped with radio sets as shown in the photo. Owing to the fact that the sets are worked from a loop antenna, it is claimed that they are extremely di- rectional and several incidents have been cited where people operating transmitters without licenses have been detected and, after consider- able maneuvering, located. One may well ask how a set such as this manages to get sufficient current to operate a transmitter on a loop and which must, of necessity, have a very low wave-length and, necessar- ily, low power. But when it is re- membered that the receiving station on each, as well as that at the cen- tral station, are extremely sensitive, it does not take very much to con- vince even the most sceptical that this is a most practical device. Digitized by Google

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RADIO WORLD If Radio and the Woman Crystal D. Tector Gives Her Views on the Exposition and Adds a Few Words About Radio's First Year WELL, will wonders never cease? I was never so surprised in all my life as the other day. I was shopping and decided that I needed a new pair of shoes. Imagine my surprise when the salesman asked me if I had seen the "Radio Boot." "My goodness I Have they shoes with radio sets in them now," I murmured. "Oh, no !" replied the salesman. "That just signifies that it goes on and off in a flash, and right over your other shoes. You see, they're overshoes." I wonder when they will cease to call every new thing that they bring out on the market "Radio." It is trying to think of other things when they are always flaunting the name "Radio" before your eyes. * * * EVEN in this age of enlightenment and daily newspapers some people never catch up with the times. A friend of mine was city-bound one day last week, and, as I had a slight headache, I asked her if she would get me a bulb, not thinking for a moment that she didn't know. Later in the afternoon she stopped in And imagine what she brought me — a Chinese water-lily bulb. • * * FRIEND HUSBAND gave me the most delightful two-step amplifier for Christmas, and I gave him six of the loveliest lace "hankies." Nothing like husband and wife knowing what to give each other for presents, is there? » * * A YEAR ago, when radio first started to boom, there were certain people that said, "Oh, it's just another fad I It will soon die out, and then a lot of people will be out a lot of money spent on expensive apparatus. Instead of that, radio turned from a popular fad into a pub- lic service. It is going all the time — and unless you have the apparatus to receive it you will never know that it exists. A great many prominent people have expensive radio sets installed in their homes, on their yachts, in their hunting lodges, in fact, any place where they want to keep in constant touch with the world. Many big business men have even gone so far as to have sets installed in their offices and employ ex- pert operators to keep them in touch with the latest news. How long before various branches of large business will carry on communication from city to city by radio is only a matter of time. Then will radio be one of the most important factors in business as well as private life. Think of the many invalids whose lives are brightened through the agency of radio. Also the many men and women who are isolated on lighthouses and fire-stations throughout the land, who suffered for want of something to keep their minds active, but now are kept in touch with the outside world. * * * DID it ever occur to some of you when listening in that the man doing relay work with a spark set is doing it for your benefit? Many a man who, years ago, used to carry gro- ceries after school to earn money to buy some new apparatus for his set, now writes R.E., or E.E., after his name. A num- ber of them hold responsible executive positions with radio corporations. _ If one of these men interferes with you when you are litsening in to a radio concert, see if you can't get your set to tune sharper before laying the blame on him. • • • LIKE a dutiful radio fan, Friend Husband took me to the American Radio Exposition. Those who didn't go will never know what they missed. The show was simply marvelous. The only unpleasantness I encountered was that F. H. was tired and impatient Even the fact that they had a set of ivory and gold couldn't remove the grouch that had encompassed him. I never saw such a wonderful display of simply marvelous apparatus. There were sets and sets and sets and sets. And one was more wonderful than the other, unti! you wondered where they would stop. There was a set so la.n? that it would fill an entire room, and there was a set so small that you could carry it around in your vest pocket. There were sets that needed no aerial or ground — not even a loop. I mustn't forget the wonderful program they broadcast there from WEAF. I haven't ceased wondering yet how it was possible to fill that entire hall with music. Just think of all the power amplifiers that were necessary. You could even hear the announcer's breath. It sounded like the north wind soughing through the trees. And when he spoke— well, his voice just filled every corner of that wonderful building. A ND not only that, girls, but you should have seen the styles at the exposition. Friend Husband made the remark that he thought they had combined a fashion show in radio along with a fashion show for women; but, even at that, all the fashions in the world couldn't keep me any busier than I was looking at the different sets. One manufacturer, seeing me standing outside his gate, kindly invited me in and explained in detail just why ail the people owning radio sets should use storage B batteries. I never met a more pleasant man in all my life, but F. H. says that he took me for a "hick" and wanted to sell me something. * * » ONE little incident that I carried away with me will remain rn my memory for a long, long time. There was a little, thin youngster, who had worked his way through the crowd surround- ing the large motor-truck that housed the speech-amplifying apparatus, which made it possible to broadcast the program from the exposition. He was looking up at the man working the instru- ■ ment with longing eyes, and trying to keep his place in the eager,, pushing, milling crowd. The operator looked down and, noticing that mite of a boy in the crowd, so interested that he did not seem to give attention to anything but the operator, called the- youngster up to the truck platform. "Whatcha want? I ain't done nuthin!" said the youngster, start- ing to back away. "No, come on up here and I'll let you see how it works," the operator explained. The youngster beamed like the sun, and. walked up the ladder as if in a trance. The operator explained to him that this apparatus made it possible for this little boy to hear the speakers over the wireless. The delight written all over that boy's face will remain in my memory for many a day. My Picture for This Week By Crystal D. Tector (C. International Newi) Y CHOSE thi» picture to illustrate my pace this week, for two reasons: First because it is so extremely true to Hfe; and, secondly, because it is the little daughter of a very dear friend of nuns. The expression of rapt Interest on the child's face la sH urate, because, when photographed, she waa so Interested In the bedtime stories that she did not notice die camera. The set that is used Is ons of die newest thine* in radio, It operates on a small inside loop-aerial. My friend discarded his old set in favor of die new ons because of that fact and, also, because the tuning- is so etmpHned that his little daughter can easily handle ft. It seems to me that loop sets are coming more and more into vogue. To my mind It Is only a question of a short time when the outside antenna will be entirely discarded fca favor of the loop which has proved so much to install and handle. Digitized by Google

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16 RADIO WORLD American Radio Exposition IN a recent address before the New York Electrical Society, David Sar- anoff, vice-president and general man- ager of the Radio Corporation of Amer- ica, made the following pertinent ttate- ments: . "Commercially speaking, radio is out some two years old, but in this brief span of time it has earned for itself, and properly so, the right to be termed an industry." "Radio in its primary phase was a means of communication through tech- nically trained men— radio operators Then radio entered the home through wireless telephony, serving the entire family with entertainment, cultural, and other information. Its next application, I believe, will be to the individual." These are the utterances of a man who knows radio. And they were exemplified to the last degree in the American Radio Exposition which closed its first success- ful event at the Grand Central Palace, (C Photooews, N. Y.) hart— rtmt aid radiate, and waa cos af tl af tha New York, at midnight on December 30. The old year went out in a blaze of hilar- ity, good feeling, and prolonged wishes for the success of the world's husky baby industry. The show was a grand success. That fact was established soon after the doors «pened to receive the thousands of in- terested spectators, many of whom had traveled from distant cities to see the latest and best in radio development. The many new things were alluring. Craned necks and bulging eyes attested their attractiveness. It is hard for a writer whose space is limited to describe everything as fully as he wishes. For instance, there was a demonstration of the "talking movies," that marvel for which all "movie" fans are waiting. This film, which shows the operation of the vacuum tube, was accompanied by a talk Tka stotacrapa at tha rla+t Ulus- aaa at tl» • aahiUts at tha Tha Mttra art la aaV- contatead la an ordinary watchcaaa. Tha taanrtanm la variants, aa la •hows la tna aaatograaa, fcy a U- point switch. Tka Indnctensa la wound aa a pises of ft bar fitted h» alda tka watch, and has a wava rango of IMS mater*. A ran** of IS arias la Jafanad with this assail sat, using an outaids antenna. This iDustratsa tka tsaanattr of »arlous Tka sail liar wanted a art that eanld explaining the tube's action recorded on a phonograph record. The reproduction of the record is kept in step with the pic- ture on the screen by a very ingenious synchronizing device. The talk was prepared by a Western Electric Company engineer and delivered into a high-quality transmitter, or micro- phone, while the film was being shown. The speaker's voice was amplified by vacuum tubes before being recorded. This resulted in the voice being repro- duced in the fullest detail. The sensation on the hearer is thrilling. The voice re- production is so natural that many people refused to believe that the demonstrator himself was not doing the talking. Paul F. Godley, was an interesting figure when he talked on "The Present Outlook for Radio Art." He was per- sonally introduced to the audience by Major Edwin E. Armstrong, inventor of the Armstrong regenerative and super- regenerative receivers. These two famous radiosts created as much enthusiasm as if they had been the President and Vice- President of the country. The feature of the second day was a double marriage, broadcast over the United States and Canada. The cere- mony took place on the mezzanine floor. Miss Helen Roller became the bride of Mr Tnhn Rninrhiie»1»T Vftsc Marirar" Girstner was married to Joseph Woorn. Rev. B. F. Saxon, pastor of the Sixty- first Street Methodist Church, officiated. Both couples received a present of $100 from the management and a wedding breakfast from the management of the exposition. One of the large exhibitors of the show made a present of the re- ceiving set to each couple. A gentleman who asked to have his name withheld gave each bride a check in a sealed en- velope. Rudolph Valentino, the moving-picture actor, gave an interesting talk on "What Is the Matter with the Movies." Among the many novelties were re- ceiving sets that may be worked with- out operators and transmitters of high- speed messages which may be deciphered at will by the operator at the receiving end. Imagine the faint impulses of sig- nals from France, Germany, Russia, Eng- land and Spain being put down on paper so that anyone with a knowledge of code may transcribe them I This caused people to gasp with wonder. The amateurs had an attractive corner. Here were shown sets of amateur con- struction embodying ingenuity and workmanship. Imagine a complete crys- tal set in an ordinary bill-fold I Imagine a set being built at a total cost of 31 rente I i ^1 t,, af ana af tho ashOats. Note tha Digitized by Google

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RADIO WORLD 17 Gay With Radio Surprises (.Continued from preceding page) Some of the amateur work was re- markable in construction and design. There were lamps made into radio sets with the bulbs under the shade. Radio sets in watch cases. Radio sets in cigar boxes. Radio sets in suitcases. In short, anything that seemed possible of holding a radio set was utilized in the most workmanlike fashion. The show was in many ways, a manu- facturers exhibit. Its main purpose was to put before the public the latest prod- ucts and to sham what first-class appar- atus really is and the care taken in its manufacture. There was sets so larjjc that one had to mount a stepladder in order to reach the controls. There were manufacturers of parts whose exhibits were chiefly to acquaint the man who constructs his own apparatus with the fact that it pays in the end to buy the best apparatus. The Radio Mica Products Company re- ports the exposition a success, from the point of view of consumer interests as well as dealer buying. The Micaphone mica diaphragms for radio head-sets are stall among the biggest sellers in radio accessories and the new micaphone kode killer already has found popu- lar recognition with radio amateurs. While this apparatus involves principles form- erly used in commercial radio, this is the first practical embodiment of a radio- frequency wave-trap made to eliminate code when broadcast concerts are being received. Its simplicity and effectiveness appeal to both amateur and expert. On the mezzanine floor there is a standard 500 watt broadcasting set exhibited by the Western Electric Company. This particu- lar piece of apparatus enabled visitors who had listened to programs from sim- ilar sets to have an opportunity to in- spect it in detail. Among the home-made sets were a large number built by middle-aged busi- ness and professional men. (C Kadel * Herbert) , > In with thla hot* aat, aba bad U . — . '•timed art la abowa at tba bottom of tba photograph* V The booth that housed the automatic transmitting and receiving apparatus of the Radio Corporation of America, to re- ceive and transmit high-speed messages across the Atlantic, was always certain to draw a crowd. The messages trans- mitted were typed on a special machine which perforated a paper tape. This tape was then run through the automatic sender which controlled the transmitting station. Messages were received on a machine somewhat resembling a stock ticker, repeating the dots and dashes at the receiving end in the form of an ir- regular line, which was transcribed by the receiving operator on a typewriter, much the same as a stenographer tran- scribed shorthand. This machine made it possible to transmit messages at a speed of over 250 words a minute, to be transcribed at the leisure of the operator. If the station is tuned in, the operator could leave the set, confident that any- (Continued on following page) Digitized by Google

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RADIO WORLD With Hears' Dallas in Kansas City From C A. Cola, 3*14 Bellefontaine Street, Kansas City, Missouri ON a single-tuner regenerative receiver and one audio-frequency amplifier, I picked up WFAA, "The News," Dallas, Texas, one night last week (December 20), and heard him clearly all over the room, on a horn that I clamp on my earpieces. I • wish to ask if this isn't good for a single- variometer set with a loading coil? • * » Good for Crystal Set From John Martin, Saranac, New York I HAVE been reading your wonderful weekly since it first came out. Due to the fact that I have only a crystal set, I have hesitated writing in for a DX record, bat I have been doing such wonderful work during the past few weeks that I, too, am going to "get my feet wet" Below is a list of the stations copied in one evening on a set composed of 1 home-made loose-coupler, 1 variable condenser, Brandes phone, and galena detector. I listened in from 8 until 12:15 p. m.: WDAP, dear, not'very loud; WGY, clear and loud ; WJZ, clear and verv loud; WEAF, clear and very loud ; WAAM, the DX Nite Tha Editors at RADIO WORLD wffl ba plaasad to receive aketchas el hook-ope of the various "DX Nl.bt Owls" eeadbur In record*, with • view el puhhahias thaaa Other letters from the DX -boss" wtB be published frees week to weak^-The Editor. indistinct but readable; WHAM, clear. I have heard several other stations nearer my home; but owing to the fact that they were nearby I did not list them. I think this very good for a crystal set. » * * Challenges Arthur Lindstrom From B. L. McBrid e, Winchester, Tennessee IN Radio World, No. 37, dated December 9, I noticed the record of Arthur Lind- strom, Larabee, Wisconsin. I want to con- gratulate him on his record, but I have one just as good: Mine was made on a home- made set, using Simplex variometers, At- water-Kent vario-coupler, Standard trans- formers and G-E tubes. I have heard as far west as KHJ, Los Angeles; north to CFCA, Toronto, Canada; south to PWX, Havana, Cuba, and east to WJZ, Newark, Owls New Jersey. The total number of station* heard is 93 in 27 different States, one i* Canada and one in Cuba. * » * A DX Correction From Jamea L. Fischer, 72 Sprfns Street. Newman, Georgia TN my DX record published in Radio A World No. 36, December 2, you made a mistake. The circumference of the cage is 12 feet, not the diameter. _ I do not use any variable condenser. Kindly correct this. I now have a record of 102 stations outside the State of Georgia. I am bear- ing Porto Rico also. * * * Heard in Peru From A. C Beach, Schenectady, N. Y. IN the far-distant harbor of Talara, Peru, 4 degrees and 30 minutes south of the equator, a radio concert broadcast on November 10 by WGY, broadcasting station of the General Electric Company, at Schenectady, New York, was clearly heard by R. H. Redlin, wireless operator of the steamship "Ardmore." This is a new distance mark . for WGY — being a {Continued on next page) American Radio Exposition Gay With Radio Surprises {Continued from page 17) thing transmitted by the station would be faithfully recorded by the machine. A device, the "wave separator," was perfected by the Crocker-Wheeler Co., one day before the exposition opened. It is claimed that this device enables a per- son owning a receiving set to absolutely eliminate any station but the one that he wishes to receive. A great degree of selectivity, it appears, was obtained by the use of this device. One of the big features of the show was a huge set made by the Qapp-East- ham Co. This monstrous set was about 5 feet high and 10 feet long. In order to operate it, one had to stand on a ladder to reach the controls. It is a replica of the standard sets turned out by this com- pany and magnified a hundred times. Going to the other extreme, a set built into an ordinary watch- was also on ex- hibition. It was a perfect working model. The builder claimed for it a range from 75 to 100 miles. The phones used with this set are larger than the- set itself. This set is the work of an amateur, who attempted the smallest possible practical set that could be carried in a vest pocket. A feature which attracted large crowds was a set constructed of imitation ivory with solid gold controls. A feature of this set was its absolute flexibility, made possible by the use of tiny plugs and jacks so that any arrangement of instru- ments might be used in any hook-up. The owner could experiment with any number of hook-ups without rehooking his set. The set demonstrated was made for the boudoir of a New York woman radioist. There was also exhibited by the Radio Industries Co., a pair of huge phones which, when compared with the regular phones that every amateur uses, com- pletely dwarfed them. Just to illustrate how large they were, the earcaps of these monstrous phones measured over two feet across. Heavy cable was used as cords. These phones were actual working giants — an exact replica of the regular phones manufactured by this company. Another big feature was the Western Electric auto-truck containing the power speech amplifying apparatus. It was through the agency of this apparatus that made it possible for the hundreds of thousands of listeners all over the country to hear and enjoy the entire pro- gram of the exposition. This speech- amplifying apparatus made it possible for WEAF to broadcast the program, and to permit every person in the exposition to hear the slightest whisper of the speaker or the softest note of any instru- ment being played. A demonstration of how radio may be directed through walls of steel and con- crete was given. It was a most remark- able performance. The inventor of the apparatus, Bernays Johnson stood behind a wall at least four feet thick and direct- ing his voice at will through it. It is pos- sible, according to Mr. Johnson, to place himself and his machine, which needs no aerial or ground, inside the largest steel vault in the country, in which captivity he will talk to outsiders without the slightest difficulty — metal doors and walls having no deterring effect. In his ex- periments, Mr. Johnson has taken his ap- paratus two hundred feet into a coal mine and talked through the solid walls very clearly. Mr. Johnson first made experiments on this form of radiophone in 1908 and has won many medals. Mr. Johnson's radiophone is a radical departure from the present type phone, it being the first successful . directive radiophone. It contains no elaborate mo- tive generators or large power-tubes. Its entire motive-power is furnished by a few small dry-batteries which, in turn, actuate some unique transformers, these generating the magnetic wave. The waye_ is thrown out into the air in a whirling fashion and can be directed in a straight line just like a gleam of light through a search light. With a device of this kind it is possible to selectively communicate with a count- less number of stations. This remarkable radiophone not only transmits and re- ceives the_ voice with uncanny clearness, but is equipped with a bell-ringing device by which a bell rings when a "party" is desired, just like a present-day telephone. This is remarkable considering the fact that even the most elaborate radiophone stations require the receiver to keep the telephone receivers on his ears constantly while the number is being called. _ A new type radio-receiving set with loud- speaker, which operates entirely by dry cells and has an equal, or better, reception range than the average two-stage set using storage batteries for the filament current, has been perfected by the General Electric Company. It was shown at the exposition for the first time by the Radio Corporation of America. This set, in an attractive mahogany cabinet, with none of the tuning or other knobs visible and with no external wiring except two silk-covered cords reach- ing from the rear of the cabinet to the antenna and ground, is known as the Radiola IV. It uses three of the new type G-E tubes, which consume 60 milliamperes filament current per bulb, or 6/100 of the current used by the present type UV-201 tube. The A battery, which is the storage battery in ordinary receiving sets, consists of three dry cells such as used for door- bells. These supply the filament current at 4yi volts. The B battery consists of four 22j4-volt units, which supply 90 volts to the plate of the tubes. There is also a C battery, consisting of a small 3-film flash- light dry-battery, supplying A'/i volt to the amplifier grid. This combination insures the highest quality of loud-speaker signals. * * * The management announced that the prizes for the amateur contest, in which over a hundred radio sets had been en- tered, were as follows : First prize, $100, F. B. Ostman, Ridge- wood, Long Island, New York. Second prize, $50, Abraham Strausse, 60 East 109th Street, New York City. Third prize, $25, Arthur Faust, 1515 Eastern Parkway, Brooklyn, New York. The judges of the contest were Ken- neth Warner, eastern district manager of the American Radio Relay League of America, and Paul Godley, the first American amateur to receive American amateur signals in Scotland. Digitized by Google

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{ RADIO WORLD If World's Champion Canary Sings in Radio 1 (C. P. & A. Photos) Did you hear a little bird •insinr la your radio tha other night? Well, this may be the bird. His aame U "Baby Grand." He took first prise at the canary show in the Chicago Slnginc, with him, is Miss Edith Allen of concert fame. There were over Stf in the final chorus for the gold medaL The photograph shows champion canary, "Baby Grand" and Miss Edith Allen singing In KYW station of the Commonwealth Edison Company, Chicago. With the DX Nite Owls {Continued from preceding page) long stretch of 3,325 miles — although an even more remarkable record involving the town of Hilo, Hawaii, 5,300 miles from Schenectady, is undergoing verifi- cation. The Hawaiian audience is declared to have heard WGY on an earlier date than did Mr. Redlin at Talara, Peru, but actual confirmation is as yet lacking. In the case of Mr. Redlin, however, it has been established by checking his statements with the concert given on the date he mentioned that, unquestionably, he heard most of the WGY program, listen- ing in for over half an hour. The distance record for a single num- ber of an entertainment program is claimed by WGY, owned by the General Electric Company, at Schenectady, New York, on a report received from Hilo, Hawaii, about 4,951 miles from Schenec- tady, when the distance is calculated on the globe. The distance estimated by WGY on the map was 5,200, but this is subject to correction. London, England, has heard WJZ, Newark, New Jersey. A ship in the harbor at Cherbourg, France, has heard WGY. These distances are about 3,100 miles. The Detroit "News" frequently hears from ships in the Pacific Ocean, particu- larly "Easterner," which reports that be- tween Australia and Panama, on Octo- ber 13, it heard a WWJ concert and "greatly appreciated" it at a distance of 3,500 nautical miles, about 4,030 ordinary miles. A letter from the operator aboard the "Easterner" tells of hearing "The News' " complete concerts three successive nights, October 11, 12 and 13, while en route from New York to Australia. On the last night the ship was 2,500 nautical miles southwest of Panama, latitude 9 degrees, south; longitude, 112 degrees, west, and a calculated great circle dis- tance of 3,500 miles from Detroit. With a Small Aerial From Bernard Burkhart, UK Chicago Avenue, Freeport, Illinois I AM using a Reinartz tuner and one step of amplification. On the night of December 22, I heard the following sta- tions; WGY, Schenectady; WOR, New- ark; WWI, Detroit; WOC, Davenport; WLAG, Indianapolis; KSD, St. Louis; KYW, Chicago; MOF, Anacosta; WOAF, Kansas City; WMAP, Duluth; WOS, Jef- ferson City, Missouri; WAAP, Wichita, Kansas; WGM, Atlanta; CHCC, Calgary; WMAF, Dartmouth, Massachusetts; WFAT, Sioux Falls, South Dakota; WSB, Atlanta; KHJ, Los Angeles. Eighteen in all. _ I consider this very good as' my aerial is a. 3-wire inverted-L type, only about 46 feet long and 20 feet high. * » ♦ Cuba Heard in Kansas EDITOR, Radio World: I have a chum who catches Havana, Cuba, on a 2- variometer, 1-tube set. He is only thirteen years old and made his own set.— Albert Brown, Stafford, Kansas. '~No Wireless jfcj^^ V** set complete without it fe, ipALS AGAIN- Vever a dull evening in the home THE relaxation, the gayety and the stimu- lus which all the world is seeking, Magnavox Radio will bring to your own hearth and home. With the Magnavox Radio, every incoming signal registered by the receiving set is repro- duced to the utmost de- gree of sensitivity and power. This superiority has given Magnavox the distinctive title of the Reproducer Supreme. R-2 Magnavox Radio with 18-inch horn: this instru- ment is intended tor those who wish the utmost in amplifying power; for large audiences, dance halls, etc $85.00 R-3 Magnavox Radio with 14- inch horn : the ideal instru- ment for use in homes, of- fices, amateur stations, etc $45.00 Model C Magnavox Power Amplifier insures getting the largest possible power input for your Magnavox Radio. 2 Stage . $80.00 3 Stage . 110.00 When you purchase a Mag- navox product you possess an instrument of the highest quality and service. Magnavox products tan be had of good dealers everywhere. Write us for copy of new illustrated booklet. THE MAGNAVOX CO. Oakland, California N. Y. Office: 370 Seventh Ave. fAGNAVOX cRadio She Reproducer Supreme Digitized by Google

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20 RADIO WORLD Answers to Readers /RECENTLY received a list of the of idol abbreviations from the Govern- ment Printing Office. There are two lists. One is in the form of questions and the other in the form of statements. How may they be distinguished ? — Harry Cahn, New York City. If a question there will be an interroga- tion point after it, as "QRM?" which will mean, "Are you being interfered with?" If the interrogation point is not used it means, "I am being interfered with." » * * What is the official wave length on which the government station NAA transmits time signals? I can hear it from the local broad- casting station, but wish to get it direct. — B. F. Mason, Tenafly, N. J. The wave length on which NAA trans- mits time and weather forecasts is 2,500 meters. * * • / am enclosing a hook-up of my circuit— a single vario-coupler circuit with a variometer in the plate circuit. It does not regenerate unless I put in series with it a coil composed of a lyi-inch tube wound with No. 24 wire. Please explain my trouble. — Maurice P. Ward, Montreal. Your circuit would function better if you inserted another variometer in the grid cir- cuit. You can put the variometer you are using in your grid circuit and get better results. It should be placed before the grid condenser and leak. * * * Give me a good hook-up using the V-T 1 with one stage of amplification. — T. Peter- son, 1507 North 4th street, Superior, Wis. A hook-up suitable for your purpose was published in Radio World, No. 30, dated October 21 ; page 12. * * * 1. Can a crystal set be made regenerative without the use of bulbsT 2. Is it possible to increase the range of a receiving set by using two crystal detectors instead of oneT 3. Will a wire hung inside of a well make a good ground?— Stanley Hughes, Astoria, N. Y. 1. A crystal set cannot be made re- generative. This term is only applied to bulb or tube circuits. 2. No. No advantage will be attained by the use of two crystal detectors. As a matter of fact, it is hardly possible that two crystal detectors in the same circuit at the same time could be made to respond at all. 3. Yes. If the wire is hung in the water of the well you will have a very good ground. mm* In order to use my loud-speaker (.Bald- win phone attached to phonograph) I have to run o wire about 35 feet down the hall. Is that the cause of my second step howling when WJZ is on? I don't get the howl except then.—Dx, New Rochelle, N. Y. If you don't get the howl when other stations are on, it indicates that the length of the cord has nothing to do with the howl. Try turning down a little your de- tector and amplifier filament-current when he is on. • • * / am not able to erect an aerial on ac- count of the landlord living in the house. Is there any other way that signals may be received than on an outside aerial '? — James Diamond, New York. If you have electricity in your house, you may use your lighting system by attaching a plug that you can buy in any of the radio stores. Caution 1 Don't use any ordinary plug. Buy one that is meant for the reception of radio signals through the agency of the lighting wires in the house. Publish a hook-up of a variable condenser, 1 variometer, vario-coupler, detector tube, grid leak, condenser and A and B batteries. — Frank OUveria, Manayka, N. Y. This hook-up appeared in Radio Wo*u>, No. 35, dated November 25. • » » Is there any stated range to a crystal receiving set? Is there any special crystal that is more sensitive tot distance ?— August Perle, East Lynwood, Pennsylvania. A crystal receiving-set will generally re- ceive broadcast signals from stations within a radius from 25 to 30 miles, and spark signals from 75 to 100 miles, depending on the transmitting station. For general amateur use galena is considered about the best crystal. ♦ * * In Radio World, No. 30, dated October 21, you published a diagram of a set by Harold Day. 1. Will a Hart & Hegaman vario-coupler with the following windings be all right to use in this circuit ? Primary: 6 taps of 1 turn each, 4 taps of 10 turns each. Secondary: 40 turns. The primary is 4 inches in diameter. 2. Would a variable condenser with a series-parallel switch improve this sett 3. What is the capacity of the grid-leak condenser? 4. What distance should the variometers and coupler be from each other? — /. A. Corriveau, 39 York street, Hartford, Conn. 1. Your vario-coupler will do nicely. 2. It is not necessary to have a con- denser in series with this set as your single- turn switch takes care of the fine tuning. 3. The grid condenser should be .00025 mfd. 4. They should be separated not less than one inch apart. Latest Foreign Radio News TMROE ISLANDS, Denmark. — The J7 charge for interior radio-telegraph mes- sages within these islands will be 10 cen- times per word; minimum, 1 franc for or- dinary telegrams; and 30 centimes per word minimum, 3 francs for urgent radiotele- grams. Portugal.— The coast station of Porto is now open for radio service. Belgium. — The legal time was reestab- lished on October 8, last Denmark.— Beginning November 1, this year, the Danish interior -charge will be 10 centimes per word; minimum, 1 franc Spain. — The coast station Vigo is pro- visionally closed for public service. France. — The legal time was reestablished on October 8, last. Norway. — Beginning November 1, this year, the Interior charge on radiotclegrams originating in or destined to Norway will be 10 centimes per word, with a minimum of 1 franc for ordinary radiograms ; and 30 cen- times per word, with a minimum of 3 francs for urgtnt radiograms. The Netherlands. — The government is preparing to enlarge the present radio sta- tion at Scheveningen. The station, which will be ready for operation in the early part of 1923, is designed to communicate with all parts of the continent of Europe and will be equipped also for wireless telephone broadcasting. Samoa Islands. — Apia radio station, call letters VMB. wave 600 meters (spark), transmits daily, at 7:30 p. m. (Greenwich mean time), a weather bulletin containing a brief review of the local meteorological con- ditions, including barometric pressure, tem- perature, and the direction and force of the wind. Broadcast Bill's Radiolays By William E. Douglass RING out the old, ring in the new V— that's what we sung last night 111 start at the beginning so you'll get the story right. Last week we had two foot of snow on top of rain an' sleet — since then the road's been opened an" sleighin' can't be beat. The weather's pretty frosty, but I though it would be great to have a bobsled party New Year's Eve an' celebrate. So I made all arrangements with 01' Obedtah Brown, who runs the Elite Board an' hVry stables here in town, to fix us up a bobsled, packed with straw to keep us warm an' several extra blankets we could use in case of storm. Startin' out from our place -we drove south to Farmington, an' west from there to Goose Grease Creek like we have always done. We set there tucked in warm as toast till we reached Walnut Hill, when Lem sed, "All gents out an' push, an' that includes you, Bill!" They're always pokin' fun at me, but I don't mind it much. I always hand a good one back an' let it go as such. The hotel down at Goose Grease Creek is called a "Road House" now— I "Whan in Aran up, I s'pose to make it sound more up to date- but anyhow, they sure know how to feed you an' I guess that counts the most from soup to nuts, includin' chicken a la king on toast Min makes a dern good hostess, she had called 'em on the phone so they bad fixed things swell fer us with lots of clan an' tone. While we may live in Brussells Sprouts, in what you call the "sticks," don't ever get the idee in yer mind that we are "hicks." We dance to New York music bless my soul — I most fergot to tell you 'bout the most important feature of the lot. When we drove up I jumped out first an' run in the hotel so when the rest come strollin' in they sez, "My ain't this swell! An orchestra an' everything." I'd brought my set along. I 'lowed fer such a classy stunt we could at least have "song." The Supper Gubs big orchestra played all the time we ate an' fer our dancin' afterwards. Now I would like to state that while you may "ring out the old" us folks "ring in the new." I'll "sign off" now an' wish you all a Happy New Year, too. Copyright, 1022, WeBtlnghonae Electric * Manufacturing Company. Complete Your File of RADIO WORLD Copiu of Radio World No. 1 52 Week* for $t.W If you did not get a copy of Radio World No. 1, send us $6.00 and we will send you this paper for one year, and start it with our first issue, which will be mailed you as soon as possible after re- ceipt of order.

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RADIO WORLD 21 Radio and .the Drama ALAN EDWARDS, of The Gingham Girl," now running at the Earl Car- roll Theatre, New York City, is a radio fan and has a set in his dressing room. Between acts, the other evening, he called Bertee Beaumont into his room to listen to a lecture that was being broadcast. "Listen to this, Bertee." said Edwards, enthusiastically, "Dr. Copeland is giving a talk on appendicitis." "No, thanks," replied Miss Beaumont, I'm tired of these organ recitals." * • • "R. U. R." is soon to be produced in Paris by Firmin Gemier, and now that the radio is reaching England's shores the review of this clever play sent out from WJZ will undoubtedly hasten the Scheduled appearance of the Robots tn London. • • What is claimed to be the first record of an act having been booked for an impor- tant engagement by radio, took place m the case of Kitty Doner, who, with sister Rose and brother Ted, appeared at the Palace Theatre, New York. Miss Doner closed in England after a successful, though brief, season, and caught a boat for home. When one day out she sent a radio to her agent, Harry Weber, stat- ing that the act would be available for New York bookings the week of Decem- ber 3. Weber immediately got in touch with George Gottlieb, who books the Pal- ace, and he offered the Palace for one week. Weber sent Miss Doner a radio on Wednesday morning, November a, when the Aquitania, on which she was returning, was in mid-ocean. On the afternoon of the same day he received her confirmation and opened the following Monday. Marriages by Radio THE use of the radio for matrimonial ceremonies has been ruled illegal. It is held that mistakes enough are being made under the old-fashioned system. Marriages over the radio have aroused agitation in several states, but it has re- mained for the attorney general of New York to issue a formal ban. The bride and groom in the case involved contended that there was no difference between broadcasting marriages and broadcasting the other fight news. The attorney general was firm, how- ever, and thus disappear all chances of husbands getting divorces on the ground they got the wrong wife due to static conditions. Likewise, all prospects of wives win- ning separations on contentions that they got husbands from WJK when they ex- pected them from KDW. In fact, several serious errors of the sort have been reported already. A New- ark (N. J.) druggist thought he was be- ing married by radio to a prominent De- troit society girl a few weeks ago. He discovered two nights later that, owing to "static" he had married the author of the Uncle Piggly-Wiggly stories. In Chicago, a well-known roofing man- ufacturer perfected all arrangements to take as his mate by radio the prettiest girl in Cos Cob, Conn. Through broad- casting errors he was united in wedlock to the "Rutgers College Glee Club in Songs and Instrumental Music, 8:45 P. M." As a matter of fact, inquiry revealed he had a very close call from being mar- ried to "Sousa's Band in New and Novel Programme, 9:10 P .M." And what happened to the Cos Cob beauty? Youll never guess, Dudley. She found she had become the wife of both the Bison City Four and the keeper of the Arlington official time. A New York woman who had divorced four husbands tried a radio marriage to a fifth and discovered she had become wedded to "the Fenwood Beach Fire- men's Fife and Drum Corps in Patriotic Melodies." And then there is the matter of con- fusion in broadcasting the wedding ritual : Minister: "Do you snap-snap-click- click-snap Beatrice Marmalade take this eggs closed firm to be your Oil Can pre- ferred, bid 34; asked 36 lawfully wedded woodchuck and chipmunk fable by Thornton Burgess?" Answer: "Nothing could be finer than to be in Carolina, etc." Minister: "Do you, George buzz-buzz take this muskrat story by Dr. Arthur Oat to be your lawfully wedded-oompah- oompah-ta-ra-ra-ta, turn?" Answer : "I love the name of Nelly." Minister: "I pronounce you symphony concert and bedtime story." — H. I. Phil- lips, in "The Globe," New York. Tdl Us Tour Radio Troubles OUm ADVICE MAT KEXP TOO tfW fVJsV nrtftNftMh eWBn# ft bVklMMi iMss) 1 1 men i, — 1 NMik itriiCii RADIO INFORMATION BUREAU SS7 rim A«a N*. ■ Hi. Miami RADIO PANELS rw BUS S"«M" us WHS" LIS CLARX at TTL90M I CAST Oat STRICT HCW VSSK BETTER LOUD SPEAKERS QC TRUE CABINET TYPE **>-°0 Mat Jest • t— — ten Ml* kit* • nkM. BaaatJfel. O— p— «. TUB TONS OP PTNB CAMOtBT PHONOGRAPHS. Make rear tw» Hp art • BOMB ENTBB- . -, aPnM>LAg ar* a« «■» hart a—tracts—, wttfc SPlMULA DUPLEX— Um any beaded. Satin alack (DB) flalah. tSAa. Oak (DO) ar Mabataay (DM) aalak. SSAS. 8PIROLA SIMPLEX— Dw Baldwin ar atkar a alt. Black (SB). Oak (SO). Mahocuy (8M) Snlab. atma prtcas aa DOPLBX. SPIROLA CONCERT — Complete with built-in salt and cord. Oak (CO) or Mahogany (CM) Snlab. S1S.SS. At Daalara ar Pacta**! (C. O. D. If Prafarrad) U H. DONNEJLX MFC. CO.. Peat. B. Bam IS. ANN ABBOB, M1CB. "VAC-SfflELDS" bring in DX. This new invention enables yon to eliminate linking up the magnetic field between tubes and does away with inter-stage coupling and unnecessary noises, thus overcoming stray capacity effects that are always troublesome and which make it so difficult to tune in distant stations. "Vac-Shields" make reception worth while, also guard your tubes against breakage. Your set should have them. Specify make of tube. Alk Your Dtalwr or Order today. Bp neU, poetyoed, 11.00. ORANGE RESEARCH LAB. 41 North MtA Street Rest Oraage, N. I. DELICATE SOLDERING Both the DMBafaMtBpars' and aasalsEis' probers oa aU sum work Is raadBar solved far the taoti— t sssMtisttad tmr tfaU particular pcffpoa*. THK POST SOLDERING IKON Platinum Heatis* Unit iBtarehsBSTveihlri Tip — Universal Cbbtss* $6.00 Praea Yew DarJar or Write Awarded Gsrtlaeat* of aaretlecaw, N. T. Bveaing Mail Radio 1— Mcasi POST ELECTRIC COMPANY, (Db. 9M) 31 E. fifed St, New Task YOUR NEWSDEALER

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $150.00 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Radio Manufacturers Organize for Patent Protection WHAT is conceded to be a tremendous step forward in the clearing of patent entanglements and manufacturers' patent problems is the announcement of the forma- tion of an incorporated group, termed the Independent Radio Manufacturers, Ino, with offices at 165 Broadway, New York City. In an exclusive interview, Walter Rust, of Pcnnie, Davis, Marvin & Edmonds, attor- neys for the group, declared it to be hit opinion that the incorporation of the Inde- pendent Radio Manufacturers, marks the first important step forward in the clearing of the atmosphere surrounding the many patents and counter-patents clouding the radio horizon. "At the request of a number of important radio manufacturing concerns," said Mr. Russ, "ihe Independent Radio Manufac- turers, was organized to join various radio interests into a common cause, for defense or offense in connection with the radio patent situation. Stock is held in equal shares by all the members and the cause of one be- comes the cause of all. Of course, any action by the group is subject first to the Radio Exports to Argentina DURING the month of October, Ameri- can exporters sent $564,803 worth of radio equipment to foreign countries. The bulk of the shipments, totaling 138,- 022 pounds and valued at $463,239, went to Argentina where some new transmit- ting stations are said to be under con- struction. Of the total equipment for that country, however, approximately $300,000 worth is said to comprise receiv- ing sets. This indicates that the radio boom has spread to the southern re- publics. Coming Events The centers «f RADIO WORD wfll of all full as posted by SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chic.ro, January U to 20, Inclusive, 1923 Georfc A. Kinf, director of publicity, 417 South Dearborn Street, Chicago, DL PERMANENT RADIO PAIR POR^BUYERS, Hotel bapsrtoL Nov York City. Open from September, VU, to May, 19*3. SECOND DISTRICT RADIO CONVENTTON, Hotel Pennsylvania, New York Chy, March 1, J, and 1, 1925. FIRST UNIVERSAL EXPOSITION OP IN- VBNTIONS AND PATENTS, Grand Central Pnl- aeg. New York City, February 17 to St, Inclusive, Fifty-two issues for $6.00. Sub. De- partment, Radio World, 1493 Broadway, N. Y. C. approval of the board of directors, and it is very likely that in the event of patent dis- pute between members of the organization, such differences could in all probability, be arbitrated, or some Other friendly settlement arrived at. "The advantages of concerted action are not limited to the division df ex- pense, alone. For example, the radic-en- gineering talent represented by the various members of the Independent Radio Manu- facturers, is such that much more technical data on the history of various inventions and important anticipatory material is avail- able, to the group in a manner which would be possible in no other way. This informa- tion, at any time, prove invaluable to some one member, in need." When inquiry was made in regard to new members joining the group, Mr. Russ stated that many new names have been submitted to membership acceptance and will, in all probability, be acted upon in the near future. Many manufacturers of radio apparatus, learning of the real advantages to the entire industry offered by the Independent Radio Manufacturers, Inc., are desirious of join- ing. New Firms and Corpora- tions (The Arms and corporation* mentioned m these columns cm be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Constructive Electric Toy Company, James- town, $5,000; G. Wall, F. E. Palmer, P. R. Sulli- van. (Attorneys Rice ft Roaa, Jamestown, N. Y.) EUert ft Kellogg, 46 California St., San Fran- cisco, Calif. _ , Robert A Heffley. 1516 Curtis St., Denver, Colo. H. J. Powers, 811 Ninth St., N. W., Washington, D. C. W. H. Jackson, South Kentucky Ave., Lake- land, Fla. Peerless Electric Company, Birch St., Zeigler, m. Kimley Electric Company, Buffalo, make radio outfits, etc., $50,000; WTS. ft L. W. Kimley, A. F. Lotz. (Attorney, W. J. Hickey, Buffalo, N. Y.) The Newberry Electric Store, 747 American Ave., Long- Beach, Calif. Homcharger Instruction Book THE Automatic Electrical Devices Company, 120 West Third Street, Cincinnati, Ohio, man- ufacturers of the Homcharger, has issued a re- vised edition of ita Instruction Book, which should be valuable to any radio fan whether or not he is using the Homcharger. This book, Besides containing simple direc- tions for operating the Homcharger, contains a paragraph devoted entirely to storage battery maintenance. The information contained in this chapter will enable a fan to obtain the best service from his battery at minimum expense. The novel feature of the Instruction Book, however, is its incorporation of a complete list of all the radio broadcasting stations in the United States, Canada, and Cuba. The book has been mailed by the publishers to all Homcharger users. Copies may be secured by anyone inter- ested for 10 cents to cover cost of postage. Heard at the Radio Counter A Conversation between Customer and Radio Clerk (Part IX) "pOOD morning, madam. What cam I da tar you?** "Wall, Willie waa made a meant el • set for Christmas, and I would Fka ta gat information en new to operate ft?" "Certainly. May I ask what set It to." "Why— It b a small. Willie (interrupting)- "Aw, say maw. If* lent a crystal aati and that ain't mahogany. Pep said so." "I know what your father said, eon. Plaaao 1st ma describe the aat to tea young aaaa." "I bag your pardon, madam; but, I think. It would be easier If you examined the acta on that table ever there and picked out the ana that re- sembles the aat that yen have at are aa many am the market we has off right." "Wall, ft la exactly Ilka that email a there* only, aa I said before, the hex to any." "Say, maw, ain't that a ados motor ever "Yea, son. Don't annoy mother." "Well, madam, what seems to ho the trouble with the tot? A great many paepla have had wonderful success with similar acta." "Well, we footed around all day with it and we couldn't gat anything out af ft." "Have you erected an aerial T" "Yes, wo put one up oa the roof and, also, con- nected a piece of wire to the water pipe. I thlak the book said that waa called an earth." "They call that a 'ground', maw." "Have you adjusted your detector property T" "Oh! you mean that thing with the little of blotting paper In it?" "Yea. You should remove the find a sensitive snot. Will hero, then I can explain.*' "We left the paper in there! We really thought that it shouldn't be touched. Maybe that to the reason It won't work." "You are absolutely correct, madaae. With that paper In there. Major Armstrong couldn't receive WJZ If ho were but a mile away." "Say, maw, ain't that lady got red hair?" "Hush up, Willie! You mustn't make remarks about other people. WetL I surely thank you so much, Mr. Clerk. I am aura that It will work now that I know what is the trouble." "Absolutely. You should bo able to get very good results." "WUHe! Leave that dog alone!" {To be continued) Christmas Radio Dance at Grebe Plant A H. GREBE & CO., Inc., gave a Christmas radio party to their employees and their friends, on Saturday evening, December ZS, 199, at the Grebe factory, Richmond Hill, Long Island. New York. The dance music was furnished by the Phoebe Snow orchestra and was broadcast from Station WEAF, New York City. Loud - speakers in the factory distributed the musje so that it waa clearly heard. The affair was largely attended and the dancing by radio proved ta ha the popular attraction. Master Baldwin Phones Reduced! Singles M M Dsalers writs. Wt esrry also Eta Corp. srsducti. CLARK & TILSON I EAST 42nd STREET NEW YORK Digitized by Google

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RADIO WORLD Receiving Transformer and Circuit No. 1.CMS4- Patented December 12, US. Patentee: Ralph S. Piper, Chicago MR. PIPER'S invention is a wireless input-circuit and has as one primary object an improvement in the character of coupling between the antenna circuit and the oscillation circuit of the detector tube commonly used in such circuit. The quan- tities of energy concerned in the operation of such circuits is almost infinitesimal, and one purpose of this invention is to conserve all the energy possible and present it to the input circuit with the least possible loss. The best possible condition for energy transference from one circuit to another through a magnetic coupling of the same, requires the use of a tight or close coupling. All low-frequency commercial power cir- d an-i Five important diagrammatic views of Mr. Piper's circuit. cuits are coupled in consonance with this* principle; but in the case of wireless re- ception-circuits— which, of course, are of very high frequencies — the input circuit is concerned not alone with energy transfer- ence but must discharge other functions, such as detection and amplification. Ac- cordingly a compromise must be made be- tween a close coupling which would give the maximum power-transference and a more or less loose coupling which has suffi- cient elasticity and flexibility to permit resonance between the several circuits in- volved. "As far as I am aware," says Mr. Piper, in describing his invention, "it has been the practice to extend this loose coupling char- acteristic throughout the range of the coupling. Usually the coupling circuits are made movable with respect to each other, and hence no part of the circuits can be said to have a strictly close coupling. "I have discovered that it is possible to divide the coupling into sections, or portions. some of which may be as closely coupled as in ordinary power-transformer circuits and that the functions of a loose coupling may be relegated to certain other portions of the winding which present a decided loose coupling characteristic. The result of this arrangement is that the tight coupling por- tions will give exceptionally good energy transference and there will yet be sufficient flexibility in the coupling, as a whole, to permit of the establishment of reasonable relation upon which the efficient operation of a reception set is conditioned as regards detection and amplification." • * * For SOS Signals No. MSt£f7. Patented December 12, 1*22. Pat. en tee: Robert E. Wlnstanley, Jr., Boston MR. WINSTANLEY'S invention is de- scribed as an apparatus which, when properly adjusted, will automatically send signals without a trained operator, and will continue to send signals until the apparatus is adjusted for the automatic transmission of a different signal, or is stopped. The apparatus includes a plurality of methods constructed and arranged to send, when properly operated, a predetermined "*-f\ rt-rVTI TUDE-I iLdNG ITUDg] ,£••.„ „.•••. ...... .... g. SBiBD IT UmnuTWl f* ra^n Mb*" J Panel layout of Mr. Winstanley's device for •ending out signals of distress, signal or message. A plurality of selecting switches is provided which are manipulated to select the desired signal, or group of signals, and a master, or control, switch is provided which controls the starting and stopping of the apparatus. The apparatus may be installed in a small cabinet in the pilot house of a vessel. When cover of this cabinet is opened for access to the selector switches, the master switch will be actuated to start the apparatus to automatically send out a continuous distress (SOS) signal, together with the ship's signal letters. The apparatus is arranged to cause this signal to be continuously repeated until the various selector switches for the latitude, longitude and nature of distress have been adjusted, whereupon, upon the adjustment of the last selector switch, the continuous distress sig- nal is discontinued and the selected signals are sent out, together with a short distress signal, which is repeated so long as the cover is open or until the selecting switches are readjusted. If during the continuance of the sending of the distress signals, the distress is relieved, as for instance, there is a fire and the fire is extinguished before assistance arrives, "Nature of Distress" selector-switch may be adjusted to send an "All is well" signal, also the information that assistance is no longer needed. » • • New Tuning Coil No. l,OS,7SS. Patented November 14, 1*22. Pat- enteei Floyd Swink, St. Louis, Mo. THIS invention relates to a tuning coil, and has for its primary object the con- struction of a coil- that is more accurate in its operation and which can be more sensi- tively adjusted. It is claimed by the inventor that it has wider adjustment than the com- mercial apparatuses now on the market. * * * Rheostat for Testing Set No, 1.4M.212. Patented, November 21, 1*22. Pat- enteei Adolph R. Swoboda, Newark, N. J, X/IR. SWOBODA claims that he has invented a rheostat economical to manufacture, reliable in operation, and accessible for the establishment of con- nections under difficult conditions. The embodiment of the invention is a rheostat intended for use in a testing set wherein there are a considerable number of pieces of apparatus mounted closely together. The rheostat is required to be both directly and remotely operative. The provision for remote control involves the connecting of a large number of con- ductors to the rheostat and the connec- tions must be made after the rheostat is installed in the testing set. The making of a large number of soldered connections in a crowded posi- tion is a difficult undertaking, but Mr. Swoboda claims that his invention re- duces the difficulty very appreciably by means of an adjustable terminal-block on which the necessary terminals are mounted. After the rheostat has been installed in the testing set, together with the other pieces of apparatus, the ter- minal block may be adjusted so that the ends of the terminals present themselves to the best advantage possible under the existing conditions. WALCON RADIO FREQUENCY TRANSFORMERS THE BEST YOU CAN BUY WALCON Transformers are tested and Ku»rnntr<-<l. Particularly adapted for ose with W.D.ll tnbes. Foor new hook-nps, Including a new reflex circuit furnished without charge with each transformer. Price, $4.00. We pay postage. Dealers and jobbers : Write Jor our attractive sales proposition, backed by national advertising. Manufactured by THE RADIO CENTRE, 2 W- Broadway, N.Y., N.Y. Digitized by Google

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24 RADIO WORLD RADIPHONO ADAPTER $2.00 Here la an to be »tur If VO in wUl mmU eta., u • speaker. Thle adapter la conrtrueted of molded eeeuxastlarj. II eliminate metal Ua aad dU- terUd aotinoa. Guaranteed bj refunded, cannot enroll jou patld at II 00 and ana by panel peat prepaid. Industrial Sale* Engineering Co. •71 Bread Street. Newark. N. i. Phone, Market 9023 Da Yotl Like Clear Tame — Sharp ana DtatlactT If m try MARSH'S Vernier Variable Condc AT LAST Made In Three Style*. Dial anal Screws Complete, rally flissrstlssl. • *M • »*■'• »7-: r*- Plate 11-1 ■dare preaaptly filled. P. Marsh, 145 Nlcoll St NEW HATKN, CONN. Ths NIMeet Short Ware Tuner a Oaty MJt * PP SB 1 IV Seas' far L. W. GOODMAN DREXEL HILL, PA. Better . Merrlateoa, Pa., wrttee: UaaHlst Is raeeatrjr with ay aoODMAN. kaarS a eaiee, "We are bo* II allot oat treat Sea Fraaataae." Tbea DENVER aw la aad aaak tka sM». CHRISTMAS OFFER SEND $3.60 Cash er Moaay OraW Oaty. sad we wtl ■tall yea put la aid a peer si shsajss with a MONEY JACK I TEE that they are aa geao] I fUS-$3.M poena aaado, SYKES MFG. COMPANY is springftft d a Venue Nr ■ i. J. Small Crystal Sets Hold Their Own Lass Exponas) la Cost aad Ghre Excelleat RasolU for Short Raago TXT'lTH hundreds of broadcasting stations, » » either installed or about to be erected in the United States, there is a movement, particularly in large centers of population, toward the use of crystal sets in preference to vacuum tube sets. In the case of the vacuum-tube set, radio fans are familiar with all the difficulties encountered. When either the A battery or the B battery runs down, there is trouble; and the trouble is not so easy for the amateur to find. When tubes burn out, there is additional expense; and just before they bum out, there is a great deal of distortion, which prevents the hearer from receiving a perfect rendition of what is going on at the broadcasting station. In the case of the crystal set however, the buyer makes his purchase for $15 or $25, strings up his aerial, connects his ground lead, adjusts the crystal and immediately is able to "listen in." While it is true that greater distance than 25 to 50 miles is not obtainable, nevertheless that which is heard over the crystal set is an absolutely faithful and actual rendition of the voice or music at the broadcasting station. There is no oscillation, squeaking or squealing, which is so characteristic of regenerative tube-sets. Many radio enthusiasts have several types of sets in their homes and it is often a fact that when an important speech or symphony concert is being broadcasted from a station 25 to 50 miles from the operator's home, the operator connects up his crystal set rather than the vacuum-tube set. With a good pair of telephones to his ears and with a good make of crystal set, the operator can hear with perfect exactness the tone quality of music with all its beautiful shadings, or he can hear the voice intonations and enun- ciation of the speaker in a manner quite unobtainable with tube reception. All this costs not over $25.00 for a com- plete outfit, including antenna equipment and telephones. There are no replacements; nothing to wear out; no batteries to re- charge; no tubes to be bought and if he is satisfied with receiving the nearby stations, his set should cost him practically nothing for upkeep. On the subject of crystal sets, it should be noted that there are on the market crys- tal sets with a wave-length range from 180 to 3,000 meters. Most of the old-type sets have a wave-length range of 150 to only 800 meters and some even as low as 500 meters. As soon as Congress passes the new law recommended by the radio board, broadcast- ing will be done on much higher wave lengths and several stations can be operated in the same locality at the same time, so that a good crystal set should have a wave length range at least going up to 2000 meters and will be able to receive the broadcast material which will undoubtedly be sent on higher wave-lengths than the 360-meter wave length, to which they were formerly restricted. Most crystal sets do not have a variable condenser and this should be compensated for by having two binding posts on the crys- tal set, one for long antenna and one for short antenna. The former should have an antenna condenser connected in series with the aerial lead. In fact, a variable con- denser does not give maximum efficiency in a crystal set. Tapped coils are usually preferable to slid- ing tuners, as sliding tuners frequently wear out or become circuited. A tapped coil set is a life long investment. With two binding posts, one for long antenna and one for short antenna, the operator will be able to accom- modate his set to the conditions possibly limited and to which his antenna can be erected. Brooklyn has a radio club in one of its high schools, organized in 1910. Its success is reported as meteoric. AMEUCAN ELECTRO PHONE CO ■t FIFTH ATBNtra, NKW YOBS DISTaUBUTOBS Fan lias ok* Nattoaally Kaowa Bastta Beta DtSooamts Is JoAbsrt RADIO MAILING LISTS I2.4SS RMReDoaian. eateries 0. *. Jf LSI 4 SaSIa Hffi.' ' eeverle, ' 'V? ay States aar Set IS.SS I.7S7 RaSle Safer/ Jeeeert, ejesrlss U. S. kv Statee aar Bet. IS.SS 2*S Radio Statleaa ear Hat 4.SS 2S7 Mfn. aka atakt ass aaeetakte eea- eleto Ratio Seta aar Mat, 4.SS 2S.SSS RaSia Aaateort aad Maaaoora a? Radio Statleaa par M 7.SS Aak far arrte I rati for Caaada. Csslsad. aoar I leak TRADE CIRCULAR ADDRESSING CO. ISS W. ADAMS STRUT CMIOA60. IU- '""afesv*!??? Rl UMUAMIUTT Simple to Use A OtMBptCt portable) m mam\ smmt wilt tally charge s WO AH battery e-vta-aight for Sc. to 10c. At your dealer* or write Kui Electric Mfg. ggsjjac. y SURPRISED? Evsrytasa IeHoaeaaae WE REPAIR VACUUM TUBES Year dealer akeald kaee. Set If be seat sat. teed Street te HARVARD RADIO LABORATORIES Beaton t. Mass, Taoea relet a ea Panel Poet 0.0. 0. To Idea I offer a compreheaeive, experi- enced, efficient service for hit prompt, legal protection, and the development of hia proportion. Send sketch or model and descrip- tion, (er advice aa to coat, eearch through prior United States patents, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable roe to accurately advise client* as to probable patentability before they go to any expense. Booklet ef valuable Information, and farts for properly tSerlealna tout Idea, free en request, write today. RICHARD B.OWEN.Patetrt Lawyer St Owee BullSrae. WeeStaatea. o. O. 2278-1* Weofoerfk Bit*.. Mae Vara Otty Subscribe for RADIO WORLD. $6J0 a year, $3.00 six months, $1.58 three Digitized by >

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RADIO WORLD 23 Plate. 43 Plate ... $1.00 i ■ • • • *9U0 $3.52 l Ohms Cash with Order RADIO ENGINEERING COMPANY Fifth Ave. and 21th St, New York City Recommended by Dealer* for Reliability RADIO STORES CO! P. H VAKlUU DtWaWI ■ m Pl.rtiS— EKSUTANCB UNITS, ETC. | TRo. ' yeer d««i«r dMM't tarry. eddreu Bert D. 222 Wart 24tk Street. Nia Tore Agents ^ f A HOE MANUFACTURES OF i-* BHIBT8 wants Agents u sell complete line of shirts direct U wearer. Exclusive pattern*. Big values. No capital or experience required. Write far free samples. MADISON SHIBT MI 1X8 507 Broadway New York, N. T. $2.95 VARIOMETERS VARIO-COUPLERS These instruments, completely assembled suid guar- anteed. are perfect In construction and design. AJI parts are accurate. Easily mounted on panel. Coupler primary hat seven taps. 3/16" or hi" •haft. Effective tuning range 160 to 600 meters. WILEY VARIOMETER COMPANY 2323 So. Central Pk. Av. CHICAGO, ILL. irttMn PRICES SMASHED! Owing I* lnnrooei Id volume at boHneaj a* ava — draetle reduction. In oar quality lima Bond aud for eomplato llot ar ardor free) tea feUew- ooawlo •erln*. All nedo prepaid aid otilind Ma 14 boon after neat* at ordor. Oeeab re- liable for rebete or enbanta. Too elapfcr ant bo ploaaodt TWO STAGE AMPLIFIER PARTS Hltbeet •redo Matarlalt Poael. BekelHo 7x12 la. Drilled.... 1 1. 7S OeMeot of > oty wood to tt I.M S TrHMfonaorsT Bait erode. O tl.91 took S.BB t FUuatat Rktootati 0 tte oo.... LIB 1 Tab* eeeWte, aooo art.. O or ooiBMtlaf win M I ait Maoorlott fhrloi wlrtee oatolto .It 1 12.»» $2.71 2.M 2.2* I.7B M M laao i Froot PfcoaoL 2MB okoM Bbaoiraob, Sttt oka* Wwtara EloMrte, 22tt okM... Botootor Taboo, Ceanletbaa. Ni BaeHe Parte Maaafacturiag Compear l( PARK PLACE DETROIT, MIOHISAN 121.21 IS.tl I.M I2.BS llil . 141 . B.2I S.SS GIT HENS TRUTONK RADIO HORN— LOUD SPEAKER Pint ana to sell on ten day trial Honey bock Guarantee It boo • door, troo tana tin reel ebeold tiy Tnitorj, ood oaaporo tt atth ether* B TOD don't find Tuilono too bait, roar ■— r «U la laTended. It lo add oo a taa-doy trial awoay-book .norutoo. If not ourlod by yonr doolor writ* aa ■ DUtributort and Dealer*, write I AUTO PARTS MFG. CO. UU Trembly Are. Datrait, Utah. Detroit "News" Music Heard in Hawaii Orchestra's Playing Carried Through Ether M00 Miles in One-fiftieth of a Second A DISTANCE record for the recep- tion of a complete program of radio entertainment was established between the Detroit "News" broadcasting station, WWJ, and A. F. Costa, postmaster at Wailuku, Hawaii, November 23. On that midnight, the Detroit "News" orchestra played "Three o'clock in the Morning" in the studio in the News Building and was heard "clearly and dis- tinctly" in the Hawaiian Islands at about 6:30 p. m. The sun moves that slowly between the two points. The distance is figured at .approximately, 4,400 miles. It would take the discharge of a cannon five hours and forty-one minutes to travel from Detroit to Hawaii without the aid of electricity— if that were possible. But the notes of music on the wings of radio arrived on the beach at Wailuku in about one-fiftieth of a second after leaving the antenna of "The News." Thus radio contested the flight of time and the extent of space. The letter received by "The News" from the Hawaiian postmaster states: "It sure was some sweet music I" There were substantiating witnesses. The report from the postmaster tallies with the sta- tion log. Mr. Costa heard the whole pro- gram of the orchestra without interrup- tion. The distance record for a single number ? ™n, entertainment program is claimed by WGY, owned by the General Electric Company, at Schenectady, New York, on \ ISP°rt received from Hilo, Hawaii, about 4,951 miles from Schenectady, when the distance is calculated on the globe. The distance estimated by WGY on the map was 5,200, but this is subject to correc- tion. London, England, has heard WJZ, New- ark, New Jersey. A ship in the harbor at Cherbourg, France, has heard WGY. These distances are about 3,100 miles. The Detroit "News" frequently hears from ships in the Pacific Ocean, particu- larly the "Easterner," which reports that between Australia and Panama, on Octo- ber 13, it heard a WWJ concert and greatly appreciated" it at a distance of 3,500 nautical miles, about 4,030 ordinary miles. A letter from the operator aboard the "Easterner" tells of hearing "The News" . complete concerts three successive nights, October 11, 12, and 13, while en route from New York to Australia. On the last night the ship was 2,500 nautical miles south- west of Panama, latitude 9 degrees, south; longitude, 112 degrees, west, and a cal- culated great circle distance of 3,500 miles from Detroit. The Bed Spring Helped Out EDITOR, Radio World: The other day my aerial blew down and I couldn't listen in. I had heard a lot about using the bedspring as an aerial, so I de- cided to give mine a try. You can im- agine my surprise when, after WJZ had stopped, I tuned around and was able to pick up WRW, Tarrytown, New York, and WGY, Schenectady, New York. This was all done on one W-D 11 using the cir- cuit described by George W. May in Radio Would No. 35, dated November 25, using a variometer and condenser. The broadcasting was easily understood. I have done some wonderful work with this set, including WGM and WDAP with a regular aerial. I think that this wins the "Fur-Trimmed Safety Razor." — L. Donoheld, New York City, N. Y. Stop Snuffling Oet rid of nasty Catarrh. Stop nees- lng, hawking, (pitting; and eoughlag. Tou weren't born with that disgusting disease. You acquired It beoauao your Lungs, Liver, Bowels. Kidneys, and all other organs designed to eliminate waste matter are not functioning prop- erly. Now your vitality Is falling, your tongue Is coated, your breath Is foul and your Noee, Throat, Lungs and every part of your body are loaded with Catarrh poisons. Don't waste year time end money on dope and drugs, ■prays and washes, pllla and powder*. These can never help you. The only way to gain relief Is to drive out the waste matter and build up your body — all of It — through Nature's laws. STRONG FORTISM — The M tderp Solents of Health Pronation will re- build and restore every pert of your body and aid Nature In forever ban- ishing Catarrh and all ether ailments. I guarantee It. Mention the subjects on which you want special Information and send with 10c for postage, etc, on my "Practical Talk en Catarrh" and my free book 6w.~ LIONEL STRONGFORT Phylcal and Health Special** t Dept. 27 Newer*. Now Joraiy stronqfout Tbjs Fea feet Man FREE ADVICE SPECIAL OFFER For a limited time only. BA-1B..BBS Grebe CB-S 171 42 Prion F.O.B. Rod Book. N. J. A. V. GREGORY Bed Bank. M. 9. MICA THEY ARE GOOD t^b^hE atooBt U» natal din and .lip In too MJOA- FHONM. Bemlt — Clearer, bettor tone, on doom, all at noted Write far drooler. dLjooubbj to datlert and Jobber* IfiCAPHONBS ooU foot. Raata Mlo> Preaaeta Oo.. lit E. 414 St.. How York Look Spider Web Inductance and Discs that give the wonderful re- sults as described in Radio Age. Inductance wound complete. .$ZJS Disc Only JS Dtatram for conaectJoru fraa with order. We are manufacturers of Stor- age Batteries for Radio A mad B circuit. WRITE FOR PRICES Iroternational Battery Co. 112 Lords Street, N. W. Grand Rapids, '

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26 RADIO WORLD Complete Your Radio Library for 1922 Useful Technical Articles Published in Former Issues of Radio World APRIL 1. A 000-Mile Rsdlophooe Employing a 5-Watt Tube, by Frank A. Hsbnel. "Tsll If*. Please, How W1U ThU Sat Re- oetvet" to R. L. Braf don. Short Cuts in Reoeiver-Clroult Design, by O. 0. Room. Making a Short- Wavs Regenerator, by Fred. Chas. Ehlert APRIL & Do Too Know Tour Receiving Uqulpment, by James D. Gordon. Why a Crystal la Called a Rectifier, by Wal- ter Emmett. la Radtotelepbouy Dependable T by O. 0. Roos. Mounting Crystals In Your Detector, by B. L. Bragdon. Storage Batterlea (or Radio, by Fred. Cbaa. Bhlert APRIL IS. rtrat Prlnelplea of Electricity aa Applied to Radio, by John P. Mllea. Tour Storage Battery, by B. L. Bragdon. What Makes Radio Possible, by Edward Ui- Oround Connection aa Vital aa Antenna, by Fred. Cbaa. Bhlert. APRIL 39. Valuable Pointers on Aerial Construction, by Bdward Lin wood. What la Meant by Tuning, by B. L Bragdoa. Radio- Frequency Ampllfloatloa and Regene- ration, by Frank Armstrong. Honey-Comb Coilo and Condensers, by Bd- ward ' Llawood. Charging the Storage Battery, by B. L. Bragdon. How to Construct the Varlooonpler, by Fred- erick J. Rumford. MAT 6. The AdTantagea of Radio Frequency, by Harold 8. Potter. How to Construct, Protect and Operate a Storage Battery, by George W. May. The Beginner's Catechism, by Edward Lla- wood. Tuning and What Is Meant by It, by Fred. Chas. Bhlert. New Frequency Amplifier Brings Faintest Wares la Strong, by O. W. May. MAT 18. My Practical V. T. Detector and Two Stags Amplifier, by Frederick J. Rumford. The Prlnelplea of Rsdlotalegraphy, by Wal- ter J. Howell. The Reason for the Loop Aerial, by George W. May. Tuning and What Is Meant By It, by B. L. Braed< The Beginner's Catechism, by Bdward Lla- MAT 20. The Design of sn Amateur Receiving Set, by C White. The B Battery and the Plato Current, by George W. May. Radio Terms at a Glanos, by Fred. Cbaa. Bhlert. The Beginner'* Catechism, by Bdward Lin- Fire Undewrlters' Rules, by Fred. Cbaa. "alert. MAT 27. The Beginner'! Catechism, by Bdward Un- How to Make Tour Own Condenser, by George W. May. Tuning as Applied to Telegraphy, by Walter J. Howell. Why the Condenser Doesn't Condense, by B. L. Bragdon. Making Signals Louder with Two-Stags Am- plifier, by George W. May. JUNE 8. The Cost of a Single-Circuit Receiver, by Howell W. Miller. The Beglnner'e Catechism, by Bdward Lin- How to Compute and Build a Fixed Conden- ser, by B. L. Bragdon. Design f ilgn for an Amateur's Receiving Bet. by C White. Simple Method of Recharging a Storage Bat- tery, by John Grayson. JUNE 10. Badlo ReeelTSr for Short Wares, by George W. May. How to Filter Atmospheric Condition!, by 0. White. The Meaaenger Boys of Broadcasting, by B. U Bragdon. Are Ton n Member of the N. O. D. C.T by B. L. Bragdoa. The Beginner's Catechism, by Edward Lin- How to Construct One- and Two-Slide Tuning Colls, by George W. Msy. JUNE 17. The Vacuum Bulb's Start in Life, by C. White. How to Select the Right Set, by B. L Brag- don. The Beginner's Catechlem, by Bdward Lin- Test of Inductance Colls, by Fred. Cbaa. Bhlert. Short Waves from a Simple Receiver, by Stanley Bryaut JUNE 24. How lo Make Tour Radio Cablets, by W S. Standi lord. How the Crystal Detector le Deed to the Best Advsntage, by C. J. Williams. How to Construct a Long-Ware Regenera- tire Receiver, by George W. May. Teated Invention of Major Armstrong Ampli- fies Set 100.000 Times, by John Kent. Repairing Cracks In Hard-Rubber Storage Battery Jars, by W. 8. Standitord. The Beginner's Catechism, by Bdward Lin- wood. JULT 1. Novel Unit-Detector and Amplifier, by Fred- erick J. Rumford. Why Tou Must Use a Condenser, by C. J. Williams. How Wars Lengths Travel, by Fred. Cbaa. Bhlert Radio World's Revised Dictionary, by Fred. Chas. Bhlert. The Beginner's Catechism, by Bdward Lin- Uss of the Vacuum Tubs Detector, by George W. May. JULT 8. Radio's Place in the Phenomena of Nature, by B. L. Bragdon. The Function of the Loose Coupler, by Charles H. Plath. Armstrong's Superregeneratlre Amplifier Fully Explained, by John Kent. Operating a Transatlantic Station, by Fred. Chas. Bhlert. The Beginner's Catechism, by Bdward Lla- wood. Reducing Strays and Static, by Fred. Chas. Bhlert. JULT 16. Assembling s Detector end Two-Stage Ampli- fier, by H. 8. Stanford. Combined Radio and Audio Frequency Ampli- fication, by C. White. Tbe Beglnner'e Catechism, by Bdward Lla- wood. Locating Your Aerial, by Harold Day. Facta tor Beglnnsra, by Fred. Chas. Bhlert. JULT 22. When Tour "Movies" Come by Radio, by Staa- ley Bryant. Underlying Principles of the Vacuum Tube, by George W. May. Practical V-T Detector Panel, by Frederick J. Rumford. Revised Radio Dictionary, by Fred Okas. Ehlsrt. Ths Beginner's Catechism, by Bdward Llawood. Importance of Aerials to Radiation, by C White. JULT 29. The Vacuum Tube as s Transmitter, by Charles H. Plath. My 20-KUowatt Tube and Its Uses, by Irving Langmulr. Importance of the Capacity Switch, by B. L B?he0 Truth about Lamp-Socket Aerials, by Harold R. Hart AUGUST 6. How to Construct snd Operate the Armstrong Snperregenerstlve Circuit, by John Kent Using Rsdlo Frequency to Extend Range, by George W. May. Things Every Radio Fan Must Know, by K. B. Hswley. Revised Radio Dictionary, by Fred Charles Ehlert AUGUST 12. The Work of the Audio-frequency Transformer, by George W. May. Practical Measurements of Capacity and In- ductance, by W. A. Dickson. Experimenting with Armstrong Circuit Pro- duces Unusual Hook-up, by Dr. 0. 8. Kelly. How to Secure Perfect Regeneration, by Fred. Cbaa. Ehlert AUOU8T 19 How to Build a Portable Field Busser, by Da Witt H. Thompson. Using Two Tubes for Receiving, by C. White. Tbe Storage Battery si sn Important Factor In Radio Reception, by Donald Van Wyck. Tbe Use of Capacity In a Circuit, by George W. May. The Beginner's Catechism, by Bdward Llnwood. AUGUST 2(1 How to Build a Splder-Web Receiver, by Frederick J. Rumford. My Detector and One-Step Amplifier, by Fred. Chas. Ehlert. The Beginner's Catechism, by Edward Lla- wood. Hints for Fans, by C. F. Rye. 8EPTEMBER 2 Generating C-W for Transmission, by C. White. Wonders of Radio-Frequency Amplification, by H. 8. Potter. How to Connect the Electric-Light Socket Aerial, by John Kent Practical Circuits for Regenerating Load Sig- nals, by O. 8. Kelly. SEPTEMBER 8 Radio Ideas for the Amateur to Teat Oat by Carl Masson. How to Make a Practical Ware- Meter, by Frederick J. Rumford. How to make a Honey-Comb Coll with a 1 Btage Amplifier, by Fred. Cbaa. Bhlert Perfect Short- Wave Radlo-Frequeaey fleatlon. by George W. May. SEPTEMBER 18. How to Maks a Two-Tube Buperrogenerator. by Frederick J. Rumford. Metboda of Amplifying Radio Signals, by B. Bradbury. Voice Distortion In Vacuum-Tubs Receivers, by W. A. Dickson. Charging a Battery— from a French Radlolsfs Point of View, by Mariua Thou rats. Working Diagrama for Beginners. 8K1-TKMBER 28, 1822 New V T Hook-up Worth Testing Out, by P. F. Metsler. New Method for Lighting Filaments, by C White. Why the Badlo Compass Is the Fighting Element of Science, by Ortherus Gordon. Complete Table of Symbols Used in Radio Reception, by Fred. Chas. Ehlert. The Radio Primer, by Bdward Llnwood. Complete Method for Building an Elect ron- Tube Detector Unit, by Experts of tbe United States Buresu of Standards. SEPTEMBER 80, 1822 Increasing the Wave Lengths of a Receiv- ing Set, by Oeorge W. May. The Importance of the variometer to a Re- ceiving Set. by Donald Van Wyck. Successful Stunts of an Amateur Badtoiat. by C. F. Rye. Employing Jacks with a Two-Stage Ampli- fying Receiver, by Fred. Chan. Bhlert. OCTOBER 7. Superheterodyne Receiver ss Applied to the Armstrong Superregenerstive Circuit, by Charles R. Leutt. Constructing s Radio- Frequency Regenerates', by C. White. Why the Open Antenns Is Beat for the Rsdie Listener, by C D. Wagoner. Broadcasting Stations of United States sad Csnsds. The Radio Primer for the Beginner, by Lynn Brooks. OCTOBER 14. Neat Home-Made Tube Socket, by Cordon S. Arthur. Veaaela Now Guided Through Fog by New Syatem of Radiotelegraph/, by Otherus Gordon, What Makes the Receiver Work, by Donald Vsn Dyck. Using the Variocoupler in a Short -Wave Re- ceiver, by George W. Msy. Regenerative V-T Receiver lor Short Wares, by Fred. Chat. Ehlert. OCTOBER 2t Important Improvements in Radio Receivers, by C. White. Be Sure of Your Ground Connection, by Fred. Chas. Ehlert. How Rsdio Wss Installed in Our Home, by Hsttie Briggs Hsrtmsn. One-Tube Regenerator Hook-up for Loud Bigs, by Harold Day. Every Radio Set Has s Reliable Range, by John Kent. The Theory of Radio Communication, by Horace Beers. OCTOBER 28. A simple Super-regenerative Receiver, by Har- old S. Potter. Vscuum Type of Arrester Ssfe, by Fred. Chss Ehlert. How to Make Your Aerisl Function, by Horace Beers. How to Avoid Interference When a 389 Meter and a 400 Meter Station Are Operating Simul- taneously, by C W. Horn. NOVEMBER 4 Receiver for Amplifying Weak Signals, by Hor- ace Beers. How to Learn the Code, by Ortherus Gordon. Detectors— and How They Work, by DoanH Van Wyck. One of the Most Delicate Parts of a Receiver, by George W. Msy. Wave Meter for Amateur Operators, by United States Bureau of Standards Experts. NOVEMBER 11 How to Build s 100-Meter Concert Receiving Set by Frederick ). Rumford. Wi<*e f ield for Experimenting with Aerials, by Donald Van Wyck. Single-Tube Superregenerstive Receiver, by «. White. Utilizing Ford Spark-Coils for Audio- Frequency Transformers, by Ortherus Gordon. _Why It Is Necessary to Tune In, by Arthur G. Shirt. Any single copy of Radio World, be- ginning with No. 1, mailed on receipt of 15 cents postpaid. Amy s«vea issues far $1.00. All 40 iaauea to date for $SJ8_ Or sand $6.00 for 1 year (52 snmben) sand have your subscription start from No* L Radio World, 1403 Broadway, Now York Digitized by Google

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RADIO WORLD 27 Build Your Own Set "THE RADIO CONSTRUCTOR" % A book showing twelve priie hook- 1 |Tv ops and lull details of just how to III build your own set saving half its cost. PrtsiM t. Nmas A Co., 74 Dey St, New York Advantages of Code AETACO TUBE SET 1 W. D. 11 Socket 1 W. D. II Tuba lCrM Look C I "B" Battery. 2Z*i volU I "A" Battery, dry cell I Variacaiiplsr I •V Plate Cewdonoer Wire lor Heok Up Free 1 Panel. TKsMM $10S DeuUe Circuit New W, D. 11 -Tub. Sat. wttb A A B Batteries. laetde Us7. Geldea. Oak Cehlaet. Complete with tube and SPECIAL, $30.00 Attack Aatenaa and Ground and get DX. Metal Dials W-.^ Varlecaoters WAS Up Vorlocaup'ora We Variable Qiadaassr $14* Argue Ugbtahtg Arresters He Crystal Detector 'ee Tunkaj Cue *ZJ» AB at theee quotations are one-half die fornwr lift pricHi Electro Technical Appliance Co. Fulton Street (mail ordera) New York City MOUNT YOUR PARTS ON A BAKELITE PANEL CUT ANY SIZE H" THICK lc PER SQUARE INCH. OTHER THICK- NESSES IN PROPORTION "Woodehorn" loud speaker BUxbmrm Amplification. No Metallic Sound. No Distorted Tones. Stands W high, has W beD. Beautiful finish la black crystal, complete with apodal attachment. For use with any f£Q VARIOMETERS AND VARIOCOUPLERS Queens, KM Type SZJ* A Few More Antenna Plugs At «c Tuska 4" Dials While They Last *•& RADIO MAP LATEST EDITION Pamtaringi District Divisions, Time DMaan, and An U. S .and Canada Broadcasting Calls 35 Canto Alt special* in November and December issues of RADIO WORLD are good now except VV200, I7T201. WDU and TT-1 tube: Pottage must be included with order. Check* •met include 10c. exchange and please have them oertifled. AH good* are shipped P. P. insured. RADIO DISTRIBUTING ft AUTO SUPPLY COMPANY M Want Mth Street, Now York City Braadway-7th Avenue Subway eth or 9th Avenue L Sabaxribe for RADIO WORLD. f&OOa year, $3.00 six months, $1.50 thrte months. Why Radiotelegraph? la a Moat Na aarjr Form of Communication NOW that the radiotelephone is per- fected and we have concerts and speeches broadcast, why bother with the radio telegraph? This is one of the ques- tions the novice in radio thinks of first. The answer is worth knowing and it brings up a lot of extremely interesting things, writes Hiram Percy Maxim, president of the American Radio Relay League, in "The Tribune," New York. Speech is at best inexact. When language was invented it was never contemplated that there would be telephones with metal di- aphragms. Sounds were adopted which were very similar, and it required quite a good bit of practice for even such an ex- quisitely delicate mechanism as the human aural organs to distinguish between them. Witness the very slight difference between the sounds of "P" and "B," or "T" and "D" or "M" and "N." The alphabet is full of such similarities. The letter "S' and the double "Th" which we English speaking people use, but which is almost impossible for the rest of the world to master, are very difficult for the telephone diaphragm to duplicate. The result has been that speech trans- mitted by telephone is somewhat doubtful, and questions arise continually as to what the exact meaning was. We all know how often we have to spell out a word when using the telephone, and even that is not satisfactory, for we have to say "T" as in Tom or "V" as in Victory or "S" as in Sam. By using some familiar word we are able to get across the letter which cannot be understood when pronounced alone. Thus when we have anything exact, such as messages or railroad train despatching, we_ use the dots and dashes of telegraphy. It is easy to be sure with telegraphy for we can count the dots and the dashes and that is all these is to it. When one learns what letter is one dot, what is two dots, what is three dots, what four and what five, and what letter is one dash, what two dashes and so on up to five, and what the combinations of dots and dashes are, it is amazing how indistinct and confused the transmission can be and yet be absolutely clearly understood. Telegraphy, therefore, is the necessary form of communication in a great many services. Blame It on Inductance EDITOR, Radio World: I have been reading your magazine for a long time and enjoy it very much. I have a Grebe Receiver and have done some very fine work with it. I recently noticed a freak while operating my set. We are situated in the suburbs of Montclair, New Jersey, and my aerial runs parallel to the party telephone-line for a distance of 100 feet. While tuning around I heard a two-sided conversation on this line. By that I mean that I heard both people talking. I tuned around and happened to hear a party's name mentioned with whom I am well acquainted. It then occurred to me that the person talking was my brother. Going to the door I heard him telephoning in the lower hall over the regular telephone. I have since experimented and found out that I can tune in all the telephones talk- ing on the party line that connects with my phone. I have found that this freak, or phenomenon, is caused by the fact that my ground is the same as that used by the tele- phone company; but, as I do not cause any interference on the line, I have not changed it. I ask you to withhold my name because some of my neighbors might want to know why I smile at them so knowingly of late —73 Om Gb., F. L. C.' Fifty-two iaraes for $6.00. Sab. De- partment. Radio World. 1493 Broadway, D-X- RADIO CO. Below Are 70 Reasons For Baying at D-X DX-Radio Co. it Built With "Foundation* of Loxeett Pricmt and Town of Highest Quality" PLUGS Bulldog Grip, round telephone S1.59 Freed-Eiseniann 1.01 Torpedo US Flat US POTENTIOMETERS Am sco 125 RCA, for -A" Battery M0 RHEOSTATS Am »co US Bradteystat US Cutler- Hammer Co. 1.00 Fada Type 1.04 Plunger U0 SOCKETS Bekelite L50 China .69 F. E. 1.00 Moulded US W. D. 11 L0» TELEPHONE HEAD-SETS Brandes, Superior 2000-Ohm SAO Federal, 2300-Ohm 8.0J Turney, 3000- Ohm 6.50 Strom berg-Carlson, 2000-Ohm M.00 Dr. Seibt |2A0 "SPAGHETTI" OR TUBING l-ft lengths J0 TRANSFORMERS Acme Type A-2S SM Murad Radio Frequency 6.00 Thordarson 4 ca Jjy-712, RCA, Amplifying 7.0) TJV-1714, RCA, Amplifying 6M CONDENSERS Morehouse Tested .00025 -.0005- .001 40 Morehouse Tested .002 St Morehouse Tested .00$ jg» SOLDER Solderall, easy to use, tube 2-os .25 VARIABLE CONDENSERS 3 Plate 12s A. B. C 23 Plate 3.S A. B. C. 43 Plate 4XO CRYSTAL DETECTORS Glass Enclosed, dust proof 1.7$ Class Enclosed, dust proof LS9 DIALS Composition, 3 in. jn Composition, 3 in en 2 in., for Rheostat .." n 4 in., with knob, 180 Degrees I.75 SAFE-T GRID LEAKS Tubular enclosed in glass H. W. 1 2. 3. 4, and 5 Megohm.. , JACKS Federal, double 1 an Federal, single « grth Type, single I..] .« Firth Type, double PANELS 7*!o* RMMr- —* "J^eatlona, nana **» ::::::::::::::::: lio Remittance M^t^A^otnpariy AH Ordera. Post PaMEaeti Our Prior tATft U» JS- M 13 SJf tss its SM J* .If St- J» IM D-X-Radio Co. 123 Liberty Street New York City Digitized by Googfi

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28 RADIO WORLD Books Needed BY Every Radio Fan Experimental Wireless Stations By P. E. EDELMAN w to make apparatus te telephoned and telegraphed at— mi a, bat alao how to make assault aaaiaaaent that works for tranaaaiaeiea orer reasonable kmc distances. Then there la a boat of new information bicladsd. The first and only book to giro yon aB the receat important radio Improretmenta, eosne at whichhnVe nerer before beta raULshed. SI paces. 167 Illustrations PRICE UM Wireless Telegraphy and Tele- phony Simply Explained By ALFRED P. MORGAN One of the most com pitta and comarehea- aire treatises on the subject erer published. A study of its paces will enable oae to ■aster all the details of the wireless trace — el messages. The aathor cxplatae ta ekaple laagaage the theory and practiea Sf wireless telegraphy and telephony. 1SJ pages, 156 engraviage .PRICE «U» The Radio Experimenter's Hand- book By M. B. SLEEPER Throughout the preparation of this book, oae purpose was kept in mind— Answer the Practical Questions of the "No-rice," sf the "Beginner/' and the more adraaced "Stu- dent." This book will help in the sslssrloa or construction of simple apparatus far the transmission and reception of radio sale- graph and telephone signals. In the chap- ters on radio receivers the simplest crystal, the simple sudion, and the regeasratrre types are described in quite some detail The question of antennas, both for trans- mitting snd receiving, are taken up. A good many helpful suggestions are given which will be of considerable aid to the experi- menter. 16 chapters. Fully illustrated. PRICE 11.11 Sent postpaid on receipt of price. The three books for $5.00. THE COLUMBIA PRINT Room 326 14*3 Broadway York City RADIO WORLD SOUR, BBTAUT 4Tt« „ PUBUntas araxr wwPNRsjpat sssd as sear ssass ss I ssrd sad sddrsss It SIFT DMT.. BAOie WORLD, I4t$ anaaway, H. V. That Armstrong Circuit So much interest has been displayed in the special article, "TESTED mVENTION OF MAJOR ARMSTRONG AMPLIFIES SET 100.0X TIMES," by John Kent, that appeared in RADIO WORLD No. 13, dated June 24. 1922, the publisher decided to put aaide a number of copies for thosa who were not able to get this issue when pub- lished. Copies will be sent, postpaid, on receipt of 15c, or send in your subscription, $6.00 for one year (52 iaaoes), $3.00 six months, or $1.50 three months, and subscription will be started with the issue containing the article about Major Armstrong's Amplifier.— RADIO WORLD, MM Broadway. Subscribe direct or through your news dealer. $6-09 a year, $3.M sb months, $1.50 three months. Ratio World, 1493 Broadway, N. Y. C Digitized by Googl

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RADIO WORLD DO YOU WANT TO BUT, SELL OR EXCHANGE RADIO OR OTHER GOODS T TRY THIS DEPARTMENT AT Is A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department is intended for everybody who wants quick action on short announcements covering the b arise, scfnsag, exchanging or general merchandising in the radio field. Renders of RADIO WORLD will find that it pays to read these colnanv every week. Advertisers will get a ten-day service here — that is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy reaches as. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is 5c per word (minim am of 10 words, mdndhsg address), 10% discount for 4 consecutive insertions, 15% for 13 consecutive insertions (3 months). Changes will be is its sn standing classified ads. if copy is received at this office ten days before publication. RADIO WORLD CO- 1493 Broadway, N. Y. C (Phone, Bryant 4796). CLOSING OUT-Wcatinchofue KC set, $104.00; Crab* CR 9 Receiver, $104.5); Grebe KORK ampli- aer, $43; Oerd Phantom Receptor (no aerial-no ground), $13100, regular price $175.00: Croeley No. Vl.tB.09; AerioU Senior, $53.00; Sterling Seedier, 810.00; Brandos Phone a, S&JS; Dictograph Heed- art. SSAS; Workrlta Veriooooplere. $2.95. All new Mas. Bie discount*. Send stamp for com- Hat. nTB. RISTEY. Sprins Grove, afmn. pJSTh PATENT* r. Writs I Biila. tlasliliel. jerte. Over IS years' as- sirinri A. aL wBeeeTiac. (Beam* I ARH). Da- IT Vleter BaflEna. WaaSligSna. IX C Maiiiiiira to buainaes eetaaaUed MSI iy A M. Warn*.) SILVER MlSUtOnS-TLATlNO OOTTTTS FUR- NISHED—Stop daily grind. " liebed ISM. CLARENCE Marion, Indiana. SPRINKLE, Dept. S, EXCHANGE UTTERS vita Meade Boa 312$. SL Portland. Ore. COMMEBCIAL RADIO OPERATOR— With tea reara' experience and botding firat-elaaa Srst Grade license, deeirea poettioo aa manager of Broadeaatinc or Telegraph station. C D. Morris, tSS N. Liberty, Delaware, Ohio. BACK NO. EADIO WORLD WANTED— The MbUaber wants copies of Radio World of April SL Mail oa copiea and cm i cat issues w01 be sent you is return. RADIO WORLD. 1493 Broadway. New York City. OLD MONEY WANTED— SES0 to SSSSJO EACH far hundreds of Old and. Odd Coins. JKaeu dassd April EJ all old Coin Value nofMY. Sent else Book. 4 Get posted. Send W cents for New Dhui ot Yoa may have valusUt _____ We pay CASH. Clarke Cobs Company, Ave. S3, Le Roy, N. Y. LET. ajsfjjmjWjjAsjll PerkCteT , Ilwm JOEXY. m thssagh our club. Stamp Betty Lee, be, 4354 Broadway. Nei news and mama Oc far spedmee ceoy at HhntraSed VENTRILOQUISM taught noma. Small cost. Send 3 pel Ih lllirs and proof. Geo M-S43, 135 N. Jefferaon Ave.. Peoria, IU. of NEW YORK STAR, _ ___ _ theatrical weakly. KM l» Sir ttSftSRSTS^ ^ II coat. Send 3c stamp today for PATnrrsnv and proof. Geo. W. Smith, Room war ihaiaea t. Jefferaon Ave.. Peoria. 111. Lawyer. JOS PA' 1ST 'ehuorae.*Re»4ster3' Pas**' McGffl RM*. Washington, ft C WE NEED RADIO and Ana-net 1 If yon have unite, mail to title eSBce and client be seat you for them. RADIO WORLD. MS Broadway, New York. CASH FOR OLD GOLD, Platinum. SOvur. Diamonds, Liberty Bonds, War, Thrift. TJantis Poatage Stamps. Falae Teeth, Magneto Pi anil. Joke, Any Valuable*. Mail in today. Cash seat, astnrn matt. Gooda returned in tea days If ywa're not eausaed. OHIO SMELTING CO., 337 Hip- ped rorot Bldg.. Cleveland. Ohio. BROADOIkSTPtO MAP of the Doited States appeared in RADIO WORLD No. A Sent on receipt of 15c, coin or i " start your snbacriptioa irom that (or 53 issues). EADIO WORLD. I Now Yes* Attention! Fans and Amateurs! Have you buftt your own receiver? Are you experimenting who any par- ticular book-op l1 Are yon improving your aetF Are you doing any interesting contrac- tive work la radio? way not snore this aneesloAy* wUk your Sksnisnis of ereSber /one tsfto read RADIO WORLD svsry esssftr Wo want pictaree of receiving sets with descriptions of bow you overcame some tUScetty, or of any additional part or unit that you have added to obtain better results. These are the things that, prob- ably, the other fellow is looking for. Send In your mformatiea; pictures or what- ever you have done to Improve the art. the li iglna ir is Wo intend to print in this week, pictured information i tian of value to radio have found a newer or batter way of doing anything, don't keep the secret but teB ft to your thousands of brother Sand ha a photograph of your set with ar without accomaanytog diagrams and ■ mat— tat State whether yoa Igure in the picture yourself, or sot, and with- out any expense whatsoever to yoa we will make an engraving and puhnah it. Be sure to write your name and address plainly on photograph. i your picture at once, or if you : made a set or done anything else m making radio material, tell the boy next door all about tht * AeViroas TecauaieaJ Edhor RADIO WORLD* 1493 Broadway. New York City. N. Y. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City. PUmM send mt RADIO WORLD -for _ mumtkt, for which H—t *md tnclostd $ x ROBSCRIPTION RATES: Copy .SJ$ ...LS0 ■m Months .3.00 One Year (33 Issues) 4.00 Add SLM a Year for Foreiga and Canadian Postage. Radio World 1 Year (52 Numbers), $6.00 Used Bird-Cage for Aerial ! I4S North Sixty-Bret Street, Phlhaslphia A COMMON bird-cage for an aerial! Maybe this is interesting and again someone may have "beat me to it" and written previously of this sort of "stnfL" While working in the cellar I noticed our discarded canary-cage and the thought struck roe that it should produce results if my four-foot loop did. Anyhow, for the fan of it, I dismantled it so that I had only the top and side-wire section. I soldered a six- foot lead to it, set it on the dining-room floor, connected it to my three-tube set and in came 360-meter station, WNAT, and later YYCAU (360 meters) with the effi- ciency of my roof antenna, except for se- lectivity. It also works well as a counter- poise ground and improves my set very much if I use this in conjunction with my water-pipe ground — of course using then the roof antenna. It did still better when I hung it on a clothes line. A 400-meter station, WFI, on that same day. did not come in well, nor has any other class-B station in Philadelphia. How Radio Waves Carry On IT is a puzxle to many radio listeners, says "The Times," New York, why the radio waves of a musical concert, after striking one antenna, continue on through space for many miles, giving the same enterta-'nment to thousands of others. It i< true that each time the radio wave comes in contact «:th an obiect which will absoib some of its MrrnRth. such as an antenna or steel struc- ture, a portion of the energy is absorbed. It has been estimated that the energy absorbed by a receiving antenna is abo-it one-millionth of an ampere. The ra<lio waves in striking the antenna leave enough energy for the listener to enjoy the concert and then pass along to the next antenna as if nothing had happened. The Herman waves strike the an- tenna wire in much the same way as a wave strikes a person bathing in the surf.

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30 RADIO WORLD USE YOUR CHRISTMAS MONEY To put this marvelous radio set (the best of its kind) in your home The RADIO READING COURSE (Panel Sit* T s\V The Assembly * Detector and Toning Unit 27s A high-grade tube set that costs less than the price of parts used. Super-sharp tuning through double toned circuit and Litz-wound rotor. A real tube set for the price of a good crystal set. All the fun of as- sembling— but correct assembling made absolutely cer- tain and easy. Supplied in assembly form, panel drilled and engraved, all parts packed inside cabinet, including all -wires cut and bent and turned, ready for soldering. Complete Instruction Sheet showing inside and outside connections. If your dealer can't supply you, send check or money order for $750, balance $20 and freight C. O. D. Five Books on Radio $|97 Five complete radio In- struction books, teaching the elementary Theory, De- • sign, Construction, Opera- tion and Maintenance of radio apparatus. Gives you a thorough grasp of the whole subject. Prof. J. H. MORECROFT Attodate Editor and Advitor No tedious study — needs only to be read. Will save you money in the purchase, construction and repair of radio apparatus. Will add a hundred-fold to your pleasure. SEND NO MONEY The complete Ave books yours for only $157 and postage. Just send name and address and pay the postman $1.97 and postage Send at once for your set of five books. PROGRESSIVE DEALERS AND JOBBERS Yea want tble enre-selHng * ■nimbly Set. It meets the need* ef the big-Beet baying- el— thee c who mat • real tube eet at ■ lew price. Attractive dlerounte. Order new for early delivery, ■ate* year book problem with the Radio Beading Coarse eet of five book*. A feet Kiting Item. Write for discount* and order sample copy. Fall line ef "Quality" parte. RADIO COURSES, INC. (Dept. RW8), S52 Seventh Avenue, New York The Me«t Ueeful NEW YEAR'S PRESENT! A Year's Subscription to RADIO WORLD (52 numbers) $6.04 Add O a year extra far postage to Canada and 14t3 Broadway Now York, N. Y. At Your Service! There appeared in RADIO WORLD, dated April 1, IS, and », the following articles: April 1— A 500-Mile Radiophone Employing a S-Watt Tnbe, by Prank A. Hakncl. *Tell ate. Please. How Will This Set Receiver" by E. L. Bragdon, Short Cute in Receiver-Cir- cuit Design, by O. C Room. Making a Short- Wave Regenerator, by Fred. Chas. EbierL April B— First Principles oi Electricity as Applied to Radio, by John P. Miles. Year Storage Battery, bj E L, Bragdon. What Makes Radio Possible, by Edward Linwood. Ground Connection as Vital ae Antenna, by Fred. Chas. Ehlert. , . „ April 20— Valuable Pointers on Aerial Con- struction, by Edward Linwood. What It Meant by ~ Frequency Frank Armstrong. Honey -L denser*, by Edward Linwood. Charging the Storage Battery, by E. L. Bragdon. How to Construct the Variocoupler, by Frederick L Romford. on, oy no warn unwooo. rraai is by Toning, by E. L. Bragdon. Radio- mcy Amplification and Regeneration, by Armstrong. Honey -Comb Coils and Con- Each copy seat on receipt of 15c. per copy, er the three copies for 45c ; or better sail, send your subecription beginning with any one of these numbers, and we will send this paper for S3 issue, and you will then have a complete file for ready and content refer- enca> RADIO WORLD, MM Broadway, Hew York. W. D. 12 Amplifier Transformer Especially designed for use with W.D. 11 Tubes. Make YOUR Volt-and-a-half tube set "speak up" like a six-volt eet. W.D. 12 Transformer gives No Distortion — Maximum Amplification. Price, Only $5.00 At your dealer, or direct from Amplex Instrument Laboratories 67-A Dey Street, New York DO NT MISS ANY COPIES OF RADIO WORLD FOR 1923 Re) aare to have a complete file of Radio World for the current year. You can do this by subscribing at UMS a year (fifty-two numbers, S3.SS six months, Jl.St three months). RADIO WORLD, l«n Broadway, New York City Tony The Barber on "Da Rad-I-O-U" (Registered U. S. Patent Office) By Ed Callow HELLO Pecplal Deesa time I speaka to you about wan greata machine. It is calla Kad-l-O-U. Grabba da speecha — da song from da fresh air. De Rad-I-O-U was firsta invent by greata Italian man — Signor Marconi. Wan million peepia try to improva da work of Signor Marconi. 1 buy Rad-l-O-U for da shop— pay fiva dol' down — feefta centa week. Getta da louda-speak for da shop — use —a da softa speak for da wife. Da customer in barber shop talka too much — da barb no can do da work. Da Rad-i-O-U maka da customer leesen in — no speaka out. Da barb now can make da clean shave — no cutta da ear — da chin— da lip. Firsta time I mak' lessen in tome butcha shop geeva da price of da sheep- da roasta beef. Wan time da doc in Public Health, Unita State, geeva talk. He tella you how to sit in da chair an' resta da feet. Wen you talla da barb how to sit an resta da feet, he go craze in da head. Wan time wan wise guy, Bureau Standard, Washeenton, D. C, geeva da talk on impure shaveeng soap. He try to steala da customer from da barb. Try to make da biz for da safa-raze politish. Wan day lady from Bosta, Massachusa, Lydia Peenk, geeva talk on how to make da apple sauce. Wat we care for apple sauce ? All we want is Rad-I-O-U talk on new sauce for spaghett. I lika da grand op*. Deesa come from capital New York State. Leetla town calla Schnect'. You gat best Italian op' wen you connect weeth Schnect.' Greata stuff! Da speech on how to maka da in- coma tax maka me sick. Wat we need is some wan to tal how to make da mon to pay incoma tax. Herba Da Hoove first breenga Rad- I-O-U to Unita State. He theenk we need more wave on da land. If he come into shop of Tony Da Barb he gat acquaint weeth evra kinda wave— marcella wave — plain water wave — elec- tric wave — wava da flag. Herba Da Hoove mak' greata tnistak— he try to gat congressaman to passa da bill to controlla da wave. We tal Herba Da Hoove to lay offa Rad-I-O-U wave control. Coma to barber shop gat nice — a mar- cella wave on da dome. Resta da hand an feet— hear Congressa- man broadcuss hot air into da fresh air. Life Would Be Ideal If- -RADIO tubes grew on trees— and the _„ lx blossomed three times a year in any cjfneatat It didn't cost a young fortune to make up a S-tube radio-audio- frequency set ? Some great philanthropist started a factory saw made sets to present free to all the amateurs fe> the country? We all could have gone to the American Radse Exposition ? You could transmit without making bad friends of all of the broadcast listeners In the vicinity T Tubes didn't need B batteries T The radio shops would run "Penny Sales?* "Bur one— end for an extra cent you can t two?" When yon have company they wouldn't a lot of questions you cant explain T Ai.yone could work an Armstrong oriyne ? The folks wouldn't kick when you went «s> listen In to the DX boys and have to stay ap la»«t to do it? Somebody would Invent a battery But dieWt run down or need charging? Digitized by Google

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RADIO WORLD Orange Label Tea Special lOt Tins For smacking flavor, delicacy of aroma and a cheerful invigorating influence, drink the best tea - Ridgways Tea. Also sold in I lb., % lb. and V4lb. TINS Sample will be sent on requeit. Addres*: Ridgway», Inc., Department K, 60 Warren St., New York COLD MEDAL San Francisco 1915 GRAND PRIZE SanDie&o 1916 Digitized by Google

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RADIO WORLD This "B" Battery Will Last 5 Years A single charge will last approximately six months. When the battery becomes discharged, you do not have to throw it away like other batteries. You simply con- nect it to any ordinary lamp socket or farm lighting £lant generator— turn on the switch and within a few ours you have a battery fully recharged at a cost of less than one-half cent, ready for another six months' use. The container (patent pending) is made of genuine pure Brazilian hard rubber and has ten individual cells molded into it, which make the container measure only VA in. x 3 in. x 4}4 in. for complete battery. Each battery gives volts and can be tapped at any desired voltage from 2J4 up. For higher voltage simply connect additional units in series. The weight is only 2\ pound* complete. The units are guaranteed not to leak and are practically unbreak- able. With this type of battery signals will come in exceptionally loud and clear. The battery Is shipped to you partly assembled. All you have to do is to connect the plates together, which takes less than ten minutes to do. The directions are simplified and include illustrated drawings for assembling the battery. Over 100,000 Sidbenel Storage "B" Batteries were sold throughout the world in the last few months. It is the finest and most economical battery ever produced for radio service. Special patented plates, which are already charged and formed before leaving the factory, containing a special composition for eliminating howling and screeching, are used. This gives it a greater capacity far exceeding that of any other battery. New model, Type C 200, price unassembled, one unit $42$ New model, Type C 20, price assembled, one unit $4.65 SIDBENEL RADIO EQUIPMENT MFG. CO. 1663 JEROME AVENUE, NEW YORK •ENERAL RADIO CO., 1*5 arsat Psrtlaa*' *L. UndM. W. I. I0SC VALLARINO E HIJ0, M«*tsvl«M, urastuy. S. A. REPRESENTED BY FISHER A CO., Manias, D. f. COMPABNIE UNI VER8ELLE DE REPRESENTATION CT DE COMMERCE, Ruasi Forttatls* «*. Vsnszla. Italy Awsrs, Bsltlw* ANTONIO FRELICH, S. Man* N. 1235, J. MEISTER SOHNE, ZarU I, D0MIN00 ORTELLI A CIA. Aim NEW RADIO BOOKS Telling How to Operate a Radio Set— How to Build a Set— Principles of Vacuum Tubes and Other Radio Problems How to Make Commercial Type Radio Apparatus By M. B. SLEEPER This book describes in detail many com- mercial types of spark and vacuum tab* telephone transmitting sad telegraph sad phone receiving- equipment of all kinds. The experimenter will be able to fet a world of idea* for the design and construc- tion of his next piece of radio equipment from the very clear descripti dearly illustrated figure*. ion* and the M PRICE 7Sc Radio Hook-Ups By M. B. SLEEPER A book that gives you not only clear die grams for all kind* of telephone and fcsfe graph receiving and transmitting seta, but simple descriptions of each circuit shown and spaces for notes of result* obtained. PRICE TSc. The A B C of Vacuum Tubes Used in Radio Reception EvE.Fi. LEWIS Assoc. L R. E. and Radfa Instructor Written particularly for the person who "knows nothing about radio" but whs would like to gain aa understanding of the elementary principles of operation of vacuum tube* and various circuit* ia which they are used for the reception of radio-telegraph signals and radio- tssephoae music and speech. Illustrated. .PRICE tU* f Any of These Books Sent Prepaid on Receipt of Price. ADDRESS * THE COLUMBIA PRINT ROOM 326 1493 BROADWAY, NEW YORK Design Data for RadioTransmitters and Receivers By M. B. SLEEPER The only book that gives tables and data for designing, receiving- and traa***itts*g apparatus so that you need no knowledge of mathematics. It s the first book a be- E'nner buy* after he has learned the age ef * phone receiver ..PRICE Tie. Construction of Radiophone and Telegraph Receivers for Beginners By M. B. SLEEPER The man who wants to feat the real tarffl of accomplishment, and who is not mriseol in the merely making use of what ethers have done for him, builds bis ewa tads* apparatus. Radio men can follow the eats in "Radio Phone and Telegraph Receivers,' with full confidence, because each piece of apparatus described was first made) tested and found efficient before the final dssfgp was accepted. Special receivers, both crys- tal and audion, are ahoera in detail. Rasjen- erative circuits as well sa audio aad tads* frequency amplifiers are described with clear photos, diagram*, and working draw- ings prepared especially fer the nevtee sad the man who want* to receive the rsdto telephone broadcast. A special fsasar* is the phonograph type radio set and the loud speaker. Fully illustrated PRICE TSc. J* Digitized by Google

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15c. a Copy January 13 $6.00 a Year 52 Numbers WORLD Without Aerial or Ground, Hurls Voice Through Solid Walls For complete story of this /*emarkable invention, sea page 25 (Both photograph f C. Kadel & Herbert; This Remarkable Radio Device Fully Described in This Issue of Radio World • Many Other Big Features

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RADIO WORLD JANUARY EVENTS A CLEARANCE SALE VT-l VACUUM TUBES W. E. Guaranteed, while they last...., $6«> GUARANTEED VACUUM TUBES ... $2.7S Amplifier .$2.50 Detector "WOOD EHORN" LOUD SPEAKER Beautiful Black Crystal, 26" high, 10" Bell.. $7 » With amplifying phone attached..... ?12->i&~ Wctoajraph Loud Speakers 9MJW Dictorraph Phones *M ,fJ| Manhattan 8000, SZ.9S; *000 *■** API Murdock S0O0 *■*• 1 " ■ Amplltone MS B. C. Transformers lit MO) 150-8000 meter 8 layer bank wound coil allk wire *M All tnbes at reduced prices. Open till M o'clock every niche. Money-order or certified check must accompany all orders. SUNBEAM ELECTRIC CO. AVE. (BET. 11th and 12th STREETS) NEW YORK Telephone 2890 Stuyresant TRADE "VAC-OHULD" MARK "VAC-SHIELDS" bring in DX. This new invention enables you to eliminate linking up the magnetic field between tubes and does away with inter-stage coupling and unnecessary noises, thus overcoming stray capacity effects that are always troublesome and which make it so difficult to tune in distant stations. "Vac-Shields" make reception worth while, alto guard your tubes against breakage. Your set should have them. Specify make of tube. Ask Your Dealer or Order today. By mail, postpaid, 1 1.00. ORANGE RESEARCH LAB. 41 North 16th Street East Orange, N. I. Begin 1*23 by Subscribing for Radio W .,M..V,r<B-W)

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VOLUME TWO OF RADIO WORLD □Entered as Kcaod-rUaa matter, March 2t, ISO, at the PMI Office at New York, N. Y.. andar tka act of March J, MWJ A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 479C VoL II, No. 16. Whole No. 42 January 13, 1923 15c per copy, $6.00 a year New Government Radio Set Has Valuable Hints for Amateurs By Harold Day (C Wide World Photos) A fitting illustration that radio is commanding an important place in governmental circles of the United States. The loop used in the set photographed was probably modeled after Mahatma GhandVs spinning wheel, at least that is what It suggested to Mr. Day when ha first 1 the photograph. But by using an hexagonal loop, more wire may actually be strung on the loop than by the use of a square. This may give Radio World readers some new ideas in designing of loop aerials. The illustration also shows that radio-frequency as used with indoor aerials is becoming more and more common. It is only a matter of time when, probably, the only sets using outside aerials will be the transmitting and the long-wave stations. If you study the photograph closely, you will notice that a resistance is used hooked into the regular lighting- current with an additional device to eliminate the commutator ripple from the circuit. This, also, is an idea that Is coming into use more and more. SOMETHING to cheer the ( amateurs' hearts. The accom- panying photograph shows Con- gressman V. M. Brennan, of Michi- gan, listening in on the proceedings of the House of Representatives by radio. Mr. Brennan has introduced a bill . to provide for the broadcasting of the proceedings and debates in both branches of Congress. In Mr. Brennan the American amateur has a staunch friend and an enthusiastic radio fan. The set shown in the photograph is a radio-frequency layout using a loop. A power amplifier and horn may be seen on the desk above. Mr. Brennan considers the radio set as important in Ins office as a dictaphone or a stenog- rapher because it keeps him in con- stant touch with everything of impor- tance that takes place.' With three steps of radio-frequency and a power amplifier it is possible to hear every word spoken in the halls of Congress.

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4 RADIO WORLD Constructing a Simple Reflex- Amplifier By Frederick J. Rumford, E.E., R.E. 2 o B.Bert. Flfure 1— DUcrmmmatic front vWw of tin panel Uyout with fall —tting tie varlma hoUe. for drilling and THE so-called reflex circuit is just the device that radio fans using a vacuum-tube detector and one-step amplifier have been seek- ing. It is a circuit in which one or more amplifier tubes are made to func- tion in two separate and different op- erations. Those tubes are so con- nected that the incoming signals are both amplified before and after detec- tion has taken place. It is well known that amplification before detection is commonly known as radio-frequency amplification; and amplification after detection is known as audio-frequency amplification. I have experimented with this cir- cuit for some time and recommend it as efficient and practical; but it does not tune as sharply as the usual re- generative or radio- frequency ampli- fier circuit It will give satisfactory results and will be sure to please the most exacting fans. It can be made up at a very little cost. It is com- pact and efficient in operation. The tuning is not very critical. Any fan should be able to operate it and obtain results. This set will do the work of three radio vacuum-tubes by using only two radio vacuum tubes. This is possible by the new method of hooking-in the different instruments required. The operations are as follows : The incom- ing signal is amplified before it is de- tected through radio-frequency am- plification which brings in long dis- tances and smooths out all distortion and interference. The signal then passes to the^|fj£tor tube, or cir- cuit, for detection and through the am- plifier tube by the audio-frequency am- plifier transformer to be amplified in volume and signal strength. As will be noted, the single amplifier-tube does the work of two tubes. It acts as a radio- and an audio- frequency am- plifier. I have used this outfit in conjunc- tion with a vario-coupler and an out- door antenna. I have not tried it with a loop antenna; therefore, I am not in a position to state just what results may be obtained with this device. But if any fan or amateur who happens to have a loop antenna should try it, I would be pleased to have him write me regarding the results. The necessary parts and their re- spective cost are as follows : 1 Radiotron vacuum-tube detector, U-V 200 $5.00 1 Radiotron vacuum-tube amplifier, U-V 201 6.50 2 Filament rheostats, at $125 2.50 1 200-ohm. potentiometer 2.00 2 Vacuum-tube sockets, at $1 v . . 2.00 1 Audio-frequency amplifying trans- former 6.00 1 Radio-frequency amplifying trans- former, 150 to 500 meters 6.00 1 Jack 1.00 1 Plug 125 7 Binding posts, at 15 cents 1.05 1 Formica panel, 8x6xJ4, at 3 cents per sq. in - 1.44 1 Base of soft wood, 8x5xj4 inches.. .50 1 Grid condenser, CI, .00025 35 2 Fixed condensers, at 35 cents each, .001 mfd 70 Wire, screws, tubing, and acces- sories 2.00 to the^gfKtor /I Total $38.29 The above figures may be a little more or less one way or the other. However, the fact remains that the cost is very low for a set of this kind. Figure 1 shows the front view of the panel and the method of mount- ing the various apparatus. It also shows the symbols and proper dimen- sions for drilling the holes. Figure 2 is a back view of the panel mounted on a base. It also shows the method of mounting the vacuum tube, vacuum-tube sockets, the jack, and the radio- and audio- frequency amplify- ing transformers; also the method of mounting the binding posts. Figure 3 is an end view of the set. It shows the method of mounting the radio- and audio- frequency amplify- ing transformers along with the vacu- um-tube sockets, vacuum tubes, bind- ing posts, and rheostats. Figure 4 shows the method of the internal and external hook-up. It shows also the method of connecting the vario-coupler, and the antenna and ground connections. Great care must be taken in con- necting up this set as the least mis- take in connecting the wires at their proper and various places will cause it to function poorly, if at all. Granted that the prospective builder has secured all the necessary parts, he should first take his panel and give it a high polish with some good grade of machine oil and then sandpaper it with No. 0 sandpaper until he has a very high polish. He should then mark off for the drilling of the holes. After this has been done, he should perform actual drilling. Next mount the rheostats, poten- tiometer, jack, and binding posts on the panel, as illustrated in Figure 1. When this has been done give the soft- wood base several coats of some good insulating compound. When dry, mount the panel on the base by the following method : Mount the panel by placing one of its long edges, or sides, against one of the long edges, or sides, of the soft-wood base. Figure 2— Diagrammatic back view of panel, tag bulbs and Digitized by Google

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RADIO WORLD 5 (Continued front preceding page) Secure them firmly by means of three brass wood-screws which go through the panel from the front into the soft- wood base. Tighten them firmly, holding the panel rigid against the base. Mount the vacuum-tube sockets and the radio- and audio- frequency amplifying transformers on the base. When purchasing the radio- and audio- frequency amplifying transformers, be sure to secure those having the proper mounting symbols at the binding posts, so as to tell where the proper wire connections are to be made. This method will reduce the chances of making a mistake. In the internal wir- ing of the set, note that the writer has marked these connections on the am- plifying transformers in Figure 4. When all this is completed, the three fixed condensers are then mount- ed on the base in true relation to their respective connections. We are now ready for the internal hook-up, or connecting up, of this set. But before this is done, the figure, or diagram, illustrated in Figure 4 should be studied carefully as the most trifling mistake in the wiring will cause trouble. There is a wire which connects with the negative side of the A-battery binding-post which, in turn, connects with one of the filament sides of each of the vacuum tubes, and which, also, connects with one of the connections on the potentiometer. There is an- other wire which connects with the positive binding of the A-battery which, in turn, connects with one side of each of the two rheostats. The re- maining side of each of the rheostats connected with the remaining post on each of the vacuum tubes of the fila- ment. This wire also connects with the other side of the potentiometer. The remaining, slider connection, of the potentiometer connects with the secondary of the audio-frequency am- plifying transformers on the filament side. The opposite side of the audio- frequency transformer, marked G, connect with the binding post marked The primary connections of the audio-frequency amplifying trans- former are as follows: P connects U.V.20O, Figaro side view of the set. The be mounted as far from tb* ' Figure 4— Schematic diagram of the book-up of the apparatus. Nolo that tb* secondary of the audio- frequency transformer is hooked back to the end of tbo tuner. with the plate of the detector tube. Positive connects with the 22j£-volt postive binding post of the B battery. The fixed condenser, which is con- necting across the secondary of the audio-frequency amplifying trans- former is of .001 mfd., capacity. It is employed to allow the radio-fre- quency currents to pass. This applies to the fixed condenser which is shunted across the phones. There is a wire which connects with the lower blade of the jack which, in turn, connects with the postive binding-posts of the 45-volt B-battery connections. The upper blade of the jack connects with Radio Amateur Backbone of Country Department of and Labor Pays HI(b THE increase in amateur activities so far as the radio amateur is concerned is being heard throughout the country. Recent reports issued by the Department of Commerce and Labor place no less than that of 17,000 licensed radio amateur operators on the fast-growing list. This figure has taken practically the government officials into camp, and they now acclaim the radio amateur the back- bone of the entire country. They say that these young men constitute a reserve of trained operators, some of whom have already done their bit in the recent World War. They proved themselves to be far superior to the average commercial operator when in communication in their line of work. With this increased amount of amateur stations, and with the tendency of the grow- ing demand for more licenses, one can imagine what the air must sound like, espe- cially when on 200 meters, the wave allotted to them for their own operating use. the positive post on the radio-fre- quency amplifying transformers. The P, or plate, side of the radio-frequency transformer connects with the plate of the first tube, or the amplifying tube. The secondary connections of the radio-frequency transformer are as follows : The G, or grid, connects with one side of the grid condenser. The other side connects with the grid of the second, or detector, vacuum tube. The F, or filament, connects with one side of the filament of the second, or detector, vacuum tube. The grid of the first, or amplifying vacuum-tube connects with the binding post marked All connections are now made. The wiring should be of No. 14 bare cop- per-wire covered with varnished tub- ing. It should be rigid and straight. The vario-coupler is connected in as shown in Figure 4. As in radio- frequency, the potentiometer is used to control the circuit. Its adjustment is rather critical. If the slider is carried over too far on the negative side, a loud howl is the result. Ordinarily the carrier waves of the broadcasting station are not heard because this set will not oscillate so as to make it possible to produce beat notes, which frequently happens in regular regen- erative sets. The principal advantage in using a set of this kind is the saving in vacuum tubes. Only two tubes are used, whereas all other sets use three tubes to pet the same results. The writer will gladly answer any questions regarding this set that do not require research or experimental work, if accompanied by a self -ad- dressed, stamped envelope. Digitized by Google

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6 RADIO WORLD To the Radio Amateur with Little Money to Spend By C. fVhite, Consulting Engineer NOTWITHSTANDING the fact that, during the past year, the progress and market for am- ateur radio-material enormously in- creased, development was quite log- ical and not so wild as most people imagined. When radio started on its way to greater popularity, due to the establishment of large broad- casting centers, many of my friends :>aid it would not last since it was only one of those public fancies which, in the course of time, simply die a natural death. Such has not been the case, and, to the contrary, conditions in sales and service of radio supplies have multiplied. By careful practice of economy it is not a very hard task to keep with- in the bounds of our money supply, or budget, for radio purposes. I shall endeavor to briefly outline sev- eral economies that may be prac- ticed by various classes of novices. For simplicity of treatment, let us divide the general classification of novices as follows: first, the novice who has very little to invest in a radio outfit and does not wish to spend much on keeping the set in working condition ; second, the nov- ice who wants a small and highly efficient receiver without going to the trouble and expense of a storage A battery; third, the novice who wants a highly efficient type of out- fit that will bring in distant stations with volume and great clarity. For the first class of novice I would recommend a good crystal de- tector hook-up, provided he lives within twenty-five miles of a large broadcasting station. He should not purchase a type of crystal de- tector receiver which will have to be almost completely junked when he desires to expand his radio re- ceiver for longer ranges. For ordi- nary broadcast and short-wave re- ception, he would do well to pur- chase a variometer as the tuning ele- ment, a .0005 mfd., mica condenser as a tuning condenser to be placed in series with the variometer, and a .001 mfd., mica condenser to be used as a by-pass condenser to be placed across the phone terminals : and. of course, a gfood crystal detector in a substantial mounting. When he wishes to expand this circuit to a single-circuit regenerative, all that he will have to do is to purchase a variable condenser, another variom- eter, and the necessary accessories to go with the vacuum tube. As a crystal-set owner he will practically have no cost of operation since dry cells and other types of batteries will not be necessary. Getting Down the CoiU For the second class of novice I recommend any type of receiver that employs a detector tube and any number of stages of audio-fre- quency amplification he thinks it ad- visable to purchase ; but I would not consider any more than three stages with a regenerative detecting and tuning unit. The type of tube to be used is the new W-D 11 dry cell tube. The tube" requires an average plate voltage of 40, but takes only ampere at volts to light the filament. To economically operate a single tube, a No. 6 dry cell will serve the purpose very well, lasting, under normal conditions of employ- ment, from two to four weeks. Now, since the life of a B battery ranges from six months to a year, and, under certain conditions, even longer, it is easy to see the cost of operating a two- or three-tube out- fit will be around $1.50 a month; that is, allowing an ample sum to be set aside each month for the pur- chase of a new B battery when the time comes. Quite a bit of B bat- tery expense may be reduced if the amateur will purchase unassembled cells and solder the connections him- self. With the money that is saved by the elimination of a storage A battery and its attendant expense, the novice may purchase one or more stages of audio-frequency am- plification. Although the W-D 11 tube has all the above characteris- tics, it has two rather serious faults : first, it cannot be used for radio-fre- quency amplification ; second, when used in the ordinary type of mount- ing in a receiver, it gives out a loud microphone sound every time the cabinet is jarred, even in the slight- est manner. The first fault is not very serious, since there are quite a number of amateurs who do not wish to delve into radio-frequency amplification, and the second can be cured by de- Menin? the tube mounting especial- ly for n W-D 11 tribe. The method >s very simple. It consists in allow- • ing the tube socket to remain loose and not firmly attached to the framework, or the cabinet, as is cus- tomary. The leads running to the socket should be made of flexible wire in order not to- transmit any metallic microphone wave to the socket. To keep the tube and the socket in its place, the socket should be attached to a piece of $4 -inch felt, which is, in turn, attached, or glued, to the supporting framework. With the tube socket supporting- system modified to meet the above specifications, there will be no an- noying hum no matter how hard the cabinet is tapped with the finger or otherwise jarred. Remember, in ad- dition, that the W-D 11 tube is a hard tube and will not efficiently function as a detector with less than 40 volts on the plate, and that it has a very fine oxide filament that will stand little or no punishment from over-voltage before it is permanent- ly damaged; do not impress more than 1.5 volts across the filament. For the third class of novice I would recommend a three-tube superregenerative receiver or a re- flex receiver using three or more tubes. If the novice is well in- formed regarding the tuning opera- tion of a superregenerator, he will do well to get one, otherwise he would take a chance. But with re- flex, or superregenerative, circuits the cost of operation for home use is apt to be very high unless strict economy is followed to cut down ex- penses. With such sets, a storage B battery is really the only thing to use since the plate current will be rather high, especially when a num- ber of power tubes are employed. The A battery should be of the radio type of storage battery. The radio type is more desirable because it is so designed that it holds constant voltage on longer periods of contin- uous discharge than the ordinary automobile starter type. Naturally the amateur with such batteries to supply filament and plate power must have an ample and good way to recharge the same. It is most likely that a motor-generator of some sort, depending upon the ini- tial power supply, would prove far more economical in the end than a tube rectifier. The amateur will do well to investigate the various types for A and B battery recharging ap- paratus now obtainable. Digitized by Google

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RADIO WORLD 7 My New Noninterfering Detector By Harold P. Donle Chief Engineer Connecticut Telephone and Electric Co., Meriden, Conn. C A r Ficon L Diagrammatic Ulustration ol the co— traction ol the Dante nae^terferbc detector tube. In this Oliutrmtian, (F) is the HUnwt, which after pwuf threua-h the tnbo, to cinntiil to the outside of tho' fleas, where it act* as a boater (H), far th* anode (A) which to awtalftc •odfaan. This heater's purpose to to aula tain a proper caarattoe- temperature for the mo lis (O ■ fha collector tU> Inula, aaada of metal and located fUractly above tba filament (F). Too photograph at tha rteht shows tho hv Tanter, Mr. Donle, and his now tube, which, bacaoso of its toaWHty to produce oocflTation, to known as tha "noulnterforin*- detector." Ona of las peculiarities i ennacted with tha operation of this tnbo to that If tho tslsphoasa aro placad in tba eoDaetar olai Inula i limit Instead of tho anodo circuit, tho slcnala win ha rocoWad with prac- tically tha Muns intensity. ONE of the least efficient elements of .modern radio is, despite the large amount of development since coherer days, the detecting system. Our best detectors are insensitive things when compared to galvanometers or telephones, and there appears room for considerable advance in increasing detector effect- iveness. The ordinary three-element tube as a simple detector is not nearly sen- sitive enough to satisfy the present de- mands. Many attempts have been made to increase this sensitivity by in- cluding within the tube a gaseous at- mosphere and while extremely effect- ive detectors have been thus produced, they have required very delicate ad- justment and in the majority of cases were not stable and required constant attention. Furthermore, it has been found practically impossible to repro- duce in quantity tubes of uniformly maximum sensitivity. The three-element electron tube and regenerative circuit is largely used at present for reception of radio signals. While it gives excellent results and certainly far .exceeds in response any other method disclosed to date, never- theless it has certain disadvantages and its widespread use has created a situa- tion which is bound to retard the popular use of radio. By using the three-element detector in a regenerative circuit greatly in- creased sensitivity is secured, but if regeneration is carried far enough to give worth-while response, there is produced considerable signal distortion. Furthermore, adjustments are critical, the slightest variation in capacity des- troying the operating adjustment. What is still more important, the radiation from many regenerative cir- cuits, particularly in the hands of in- experienced operators, creates an alarming amount of interference which if continued will seriously hamper re- ception of the present broadcasting programs. There seems to be a definite need for a receiving tube which under no condi- tion can radiate any energy from the antenna to produce interference, which can be easily adjusted, which is not affected by the body capacity while the circuit is being tuned, and yet which secures all this at no sac- rifice of sensitivity and loudness of re- sponse. For several years we have conducted experiments on many different forms of detectors, and particularly upon de- tectors employing ionization of metallic atoms. This was a most promising field of development since such ionization was found to be readily controlled and stable. As one of the results of this work we have developed the present tube which is the logical result of experimental work which we have done along these lines. This new tube has none of the disad- vantages of regenerative and gaseous detector systems above mentioned. Its method of operation seems to involve many* interesting phenomena, which are radically different from those oc- rurring in other tubes. The construction of one form of this tube is illustrated diagrammatically in Figure 1 where F is the filament, A is the anode, which may be of metallic sodium in the bottom of the tube, and H is the heater, which is a short length of resistance wire cemented to the outside of the glass directly underneath the anode. This heater maintains the anode at proper operating temperature. C is the "col- lector" electrode of sheet metal bent into a "U" and positioned above the filament with its open side toward the anode. (C. Ptmtrmews) Harold P. Donle and him nonlnterforfaiff detector. Digitiz em by Google

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RADIO WORLD Next! The Set that Works without an Operator THE automatic tape-recorder is a device that promises to play an important part in radio- telegraphy. The boast that is being made for it is that it will not make mis- takes— and making mistakes is one of the faults that the human being cannot overcome. The tape-recorder not only will transmit and receive messages automatically, but at a rate of speed that cannot be distinguished by the human ear. The recorder is a cousin to the recorder now in use in cable offices. It is known as a "syphon recorder." It was developed by Lord Kelvin in the first days of transatlantic cable telegraphy. In this new recorder a very light coil is placed over the core of a very powerful electro magnet. This magnet is connected to the amplifying side of a receiver in the same way as tele- phones in evefy-day use. When an electrical impulse surges through the large magnet the small light coil moves in a vertical field. This actuates a very light arm, which is also attached to the smaller coil by means of a light link. At the other end of the arm is a pen, which rests lightly on a moving By R. L. Dougherty S — I A - S M in which • the Illustration showing the manner strip of paper It easily may be seen that when the coil is pulled down the pen-arm will move up, causing the pen to make a vertical mark. So long as any current from the amplifier is flowing through the larger magnet the pen will stay up, but the moment the current ceases the pen-arm falls. Due to the fact that signals are sent auto- matically the dots and dashes are always of the same length in respect to each other; that is, a dash is approximately three times as long as a dot; and, therefore, it depends on both the speed of the moving tape at the receiving end and the speed at which the signals are being trans- mitted just how long a mark the pen- arm shall make. This device, which at present is being used in the reception and trans- mission of high-speed messages on very long wave-lengths, has proved 'an innovation. A man sits at a type- writer, and as the tape passes before is received. The lone lines above center ate him he transcribes it in much the same manner as a stenographer transcribes her shorthand notes. Therefore, the messages may be sent at the high speed of 80 or 100 words a minute and transcribed at the receiving operator's leisure. This little machine is said to be infallible. Any one who has sat for hours with a pair of phones over his ears, listening to faint flute-like signals flashing through space and copying, copying all the time, will appreciate what this means to an operator who is obliged to work at high tension. At the transmitting end there is a special typewriter, which perforates a moving tape. The keys of the type- writer, instead of being type-face, are punches. The tape passes through a machine in which short and long dots are made the agency for the generation of the waves, which flash across limit- less space at the speed of light — 186,000 miles a second! Multicontact Switch Tunes 6 Circuits By Donald Macgrtgor (C Kaild & Hobert) This highly selective circuit is, in reality, six circuit* In one. To tune it requires the multicontact switch shown in this photograph. This circuit is used for transoceanic radiotelephony. WHILE most amateurs have dis- covered that the single circuit is the easiest to handle and is very selective in tuning, experimenters are not satisfied. The accompanying photograph shows a "selector switch" by which it is possible to tune in six circuits at the same time. It is used for transoceanic radiotelephony, and is highly selective. While the photograph shows the cir- cuit in the experimental stage in one of the large research laboratories of the country, it has been discovered that, by the use of the selector switch, which permits any one of six circuits to be used, stations which cannot be tuned in with one circuit respond very readily to another. This opens a field of intensely interesting experi- mentation. Imagine being able to rune six cir- cuits at the same time with one switch ! It seems impossible, but nothing is im- possible in radio or anything else these davs. Digitized by in radio or anytnin y Google

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RADIO WORLD 9 Use of the "Quenched Gap" in Radio By S. R. Winters -gmp radioteUfraph transmit tine outfit by th» Sljrnal Corps of ths United States Army. THE term "quenched gap" owes its derivation to the principle in electricity that a short electric-spark between cool electrodes is quenched instantly. Air becomes a nonconductor of electricity almost im- mediately after the electric spark is broken down, or as soon thereafter as the current is reduced to a low value. Such behavior is more orderly and positive if the sparking chamber is air- tight. The conventional form of quenched gap shown in the accompanying photo- graph of a portable radiotelegraph transmitting outfit used by the Signal Corps of the United States Army, comprises a series of flat copper or silver discs, the surfaces of which range from seven to ten centimeters in diameter at the sparking point. The faces of these discs are about two- tenths of a millimeter apart. High electric voltage-charging in- volves the use of a number of small quenched gaps in series, thus provid- ing the requisite length of gap or "electric bridge." The electric spark jumps, or hurdles, all of these gaps, one after the other. The copper or silver discs are separated by rings of mica, or paper. A motor-driven blower cools these discs. The latter are commonly provided with project- ing fins, fishlike, as a means of radiating electric heat. One commer- cial design of quenched gap is provided with air spaces between the pairs of discs, these serving as successive gaps. The amount of voltage used is the de- termining factor as to the required number of gaps, the ratio being about 1,200 volts for each quenched gap. Only within recent years has this form of electric energy been employed on a supply frequency as low as sixty cycles a second. Recent experimental data indicate that it is feasible to use quenched gaps with 60-cycle supply. The results are evenness of tones and satisfactory communication by the use of a variable series resistance in the primary electric circuit of the trans- former. It is likewise adaptable when employing a transformer of the reasonance design with an uncom- monly high secondary voltage. When varying the series resistance, the spark rate may be accordingly changed, as needs may dictate, to 60, 120, or 240 cycles a second. Such adjustment is beset with difficulties if line voltage variations are encountered. Radio engineers consider the out- standing advantage of the quenched gap compared to the rotary gap to be its serenity of operation. The ex- tremely short gaps and the imprison- ment of the electric spark are condi- tions which obviate the noisy char- acteristic of the obstreperous rotary gap. The Radio Communication Sec- tion of the Bureau of Standards and the Signal Corps of the United States Army indicate that when employing a 500-cycle supply with a quenched gap, it is conventional to so adjust the voltage and the number of gaps that there is one discharge to the half cycle or 1,000 sparks each second. All in all, government wireless experts are of the opinion that the quenched gap will continue to function satisfactorily under close coupling. Digitized by Google

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin ciples Fully and Tersely Explained By Lynn Brooks "JfYy HAT is the meaning of the m/E' normal rate of discharge as applied to a storage cell? This is the number of amperes that may be safely drawn from the cell without injury to the plates. This value may be found by dividing the ampere-hour capacity by the hour rating of the cells. * * * What is sulphatingf Sulphation, as applied to storage cells, is a snow-white deposit which forms on the plates. It is due to let- ting the cells stand idle too long on a discharge, or from too much over- charge. The sulphation of a cell means its complete ruination, as the active element is destroyed. * * * Name the precautions necessary when placing a battery "on charge?" ■ 1. Open the vent caps in order to allow the gas generated in the forma- tion of the charging of the plates to escape freely. 2. See that the electrolyte thor- oughly covers the plates. 3. Make sure that you have the correct polarities. 4. Make sure your resistances are in the circuit. (Generally, a battery of lamps.) 5. Never allow the battery to heat up. If it is evident that heat is being generated, disconnect and allow to cool before resuming charging. * * * What is a lightning arrester? An arrester generally consists of a very small air gap enclosed in a glass tube in which there is a very high vacuum. * * * Why is a lightning arrester safe? Lightning has the property of al- ways taking the shortest path to the ground. Therefore, owing to the fact that the coils in the circuit have con- siderably more resistance than the resistance across the minute air-gap, it will naturally take the path of least resistance — across the vacuum gap. * * * Why do they exhaust the air in such a gap? As air has a high resistance to electricity, the less air in a vessel of such an article the lower the interval resistance. Which is safer, a lightning switch or a vacuum arrester? A lightning arrester is the safer because it is automatic. As the average human being is not infallible, he frequently forgets to throw the switch, leaving the set connected with the aerial. This cannot happen in the* case of the arrester as»H; functions automatically. * * * Why must the positive (+) of the B batteries always be connected to the plate of the tube. As the filament of a tube gives off negative electrons, we must put" a positive charge on the plate. This is due to the fact that, unlike poles, have a close affinity and attract strong- ly. Had we put a negative charge on the plate we would have a like charge on the two elements and they would repel each other. Likes repel; unlikes attract. * * * How is it possible to determine an amplifying tube from a detector? Place the tube in the socket, put from 45 to 55 volts on the plate, and turn on the filament current. If, when the filament has become heated, the bulb turns blue around the plate switch off the current. This blueing denotes a soft or gaseous tube, and a detector. If it does not blue up when 55 volts are placed on the plate you have an amplifying tube (hard tube). * * * Why is a grid leak necessary in the circuit? The grid leak is a. little safety valve which allows the negative electrons stored up in the grid condenser to escape after a train of oscillation have charged the condenser to its capacity. Easy Way to Make Switch-lever Bushings and Single-circuit Jacks By Lester C. Doerr [A] [a] J Were - ** \* Dvtaib to follow ta •witch-Wvw btuUnfs ■bite-circuit jacks described fcy Mr. Doerr la tin eccotnpenjrlnj article. (A) la the boahtef (B) I* the Jack. H ERE is a little hint which may be of value to the radio ex- perimenter. Old valves from automobile or motor-cycle inner tubes, usually found around the workshop, provide a source of neat and inex- pensive switch-lever bushings. To make a switch-lever bushing, take a valve of the smaller size and cut it off to proper length with a hack saw. It should be just long enough to allow the nut to be screwed on after it is inserted in the panel. Then smooth off the rough end with a file so the nut will screw on easily. After this, drill out the hole large enough to take the bolt, or rod, to be used. These valves are of brass and nickel-plated, so a little polishing is all that is neces- sary to make a very presentable article. The larger valves may be used to make telephone jacks, especially of the single-circuit type* They are easily made. The accompanying drawings show the construction of both .switch- lever bushings and single-circuit jacks. If the experimenter desires to do so, other types may be made with a little more work. Another wrinkle is the use of 22- caliber cartridges for switch points. Holes should be drilled in the panel just large enough to make a tight fit. Connections may be made either by wedging the wire into the hole beside the cartridge, or, preferably, by sol- dering. They are more attractive if polished. If the experimenter owns a rifle, they will cost him nothing but the trouble of saving them. Digitized by Google

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RADIO WORLD 11 Panel layout for a mwrfw sat, embodying two variometers. vario- coupler, detector, and two steps of aodltt-frequenty. Suggested Drawn by R. t> Dougherty. by Cranky Mayers. How I Planned My Regenerative Receiver-Panel THE three-unit regenerative cir- cuit has come into popular use, and a number of amateurs may wish to build their own. The obstacle that stumps many of them is how to arrange all the instruments on the panel in order to conserve space and at the same time have a panel that looks at least half way snappy and workable. Here is a layout I have worked out on my own set. I have given it to several other amateurs who built their own sets and they were so well satis- fied that I thought other build-your- own fans would be interested. By Cranby Meyers I was limited, in the first place, to a panel 7 by 18 inches owing to the fact that my desk had just that much space in it; and, as I was desirous of putting it in the desk, I drew my plans accordingly. I think I have made the plans so clear that everything is fully explained in the drawing. However, if a large dial is used it will give the panel a better balance and finish because all the rheostats are at the other end of the panel. It will be noted that, on the detector, I am using a vernier rheostat. I found that this is just as necessary in fine tuning as is the variometer because I am using the W-D 11 tubes. At the same time they will amplify a signal very much better if the rheostat is turned down just a little bit. I hope that this will help some of the fellows who are building their own and are stumped at the idea of effi- ciently laying out a panel that has a balanced appearance. A few hours spent in carefully drilling the holes and paying close attention that every- thing is laid on neatly will repay the builder a thousand times, and he will have a perfect piece of apparatus. Every DX Night Owl Will Want This Article! "DX Work With a W-D 11," by Ortherus Gordon, with Full-Size Diagrams for Building, in Next Week's RADIO WORLD, No. 43, Dated January 20 — A Most Important Contribution to DX Work. Mr. Gordon, writing to the Editor of RADIO WORLD, says of his article: J WANT to say that, If you wished, you could print an unqualified guarantee that a rjuflo receiver built alone the lines shown and connected up aa shown, will meet the demands of the most fastidious amateurs. Night after night, 1 do things with this little sat which would put the plaints of the ordinary DX night owl to shame. I am feeling now, more ao than when I prepared the article for you, that it is my outstanding contribution to amateur progress daring the pest year. Last night, on an M-foot aerial, IS feet high, single wire, I tuned out WMAN at Round HilL South Dartmouth, Massachusetts, and brought fat WDAJ at College Park, Georgia, which is considerable distance for a peanut tube with no amplification. Tuning out Round Hill Is a feat In itself, for this station is only twenty mfles away and comes in tike the prodigal son— all at once and all over the place. Bringing in a station which is nearly a thousand miles distant on a dry-cell tube is genuine DX work. I should be glad to hear from any amateur who makes this W-D 11 ■et and to compare work done with it. I've been a radio bug far a long time now, but I've got bitten all over again with this W-D 11 outfit, and my brow Is as feverish aa ever. Yours very truly, ORTHERUS GORDON. 87 Smith Street, Fall River, Mass., December St, 1*22. Digitized by

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12 RADIO WORLD Battleship to Fire on Radio-Controlled "Iowa" in War Game WASHINGTON, D. C— In- direct firing of 14-inch guns by one battleship at another under way, but out of sight over the horizon, will be undertaken for the first time early in March at the Naval maneuvers in Panama Bay. The target will be the radio-controlled "Iowa" of Spanish War fame, un- manned and unarmed, but operated by an officer on the "Shawmut," several miles away. Radio will bear two very important parts in the battle practice of the com- bined United States fleet, this year: the maneuvered target ship will be sent out to sea under radio direction. When she is out of sight, indirect fire at her will be undertaken by the aid of radio observation and spotting fur- nished by airplanes. The "Iowa" is a twenty-five-year-old warship. She has more than served her time. For the past two years, she has been known as Coast Battleship No. 4, honored here and abroad as the first radio-controlled ship of war. Her actual bombardment with heavy gunfire from the "Mississippi," designated as the attacking vessel, has occasioned considerable interest not alone in the Navy but in Congress. Secretary Denby's invitation to the members of the Senate and House Naval Affairs Committee to witness the tests, has brought a flood of requests for trans- portation to Panama Bay, in March, for the scheduled bout. A program of several varieties of battle practice gives promise of an unusual spectacle seldom witnessed except in actual warfare and then only by officers and men in the engagement. The Navy is not thinking of the spectacular side, how- ever, but seeks to determine whether its present methods of range finding and fire-control, and the instruments used are efficient, and this is the first time an opportunity has been afforded. The effect of gunfire on armored ves- sels is well known as other battleships have been anchored and blown to pieces by our expert gun pointers and trainers. Literally the "Iowa" is a modern, steam "Flying Dutchman," without skipper or crew. Some time ago, far- sighted radio engineers of the Navy developed a special method of radio- telegraph control for the "Iowa" based on the inventions of John Hays Ham- mond, jr., and aided by engineers of the General Electric Company. To- day it works perfectly — her water and oil tanks are filled, her oil-burning boilers and engines are started by a i crew of caretakers. Her con- By Carl H. Butman trol ship takes her over, and the crew abandons ship. By meant of radio, her engines are speeded up and slowed down, her rudder is thrown to port or starboard, or maintained at a desired angle, and she performs within a frac- tion of a second at the will of the "master mind" aboard the control ship which may be ten miles distant A special feature of her equipment pre- vents her running away, stopping her if the control is broken, or the aerials are shot away. If no radio-control signal reaches her "electric-mechanical brain" for so long as fifteen minutes, the fires are extinguished, the engines stopped and everything shut down. This enables the crew to again board her, repair defects and start her on another "flying dutchman" cruise. Five basic problems of gunfire will be undertaken with the old "Iowa" as a moving target, in an effort to sim- ulate as nearly as possible wartime conditions. Towing a target for gun- fire restricts the angle of fire some- what to avoid hitting the towing vessel. With the "Iowa" under radio control and the "Shawmut" a safe distance away, this objection is obviated. In the first practice only, the sec- ondary batteries — the 5-inch rifles — of the "Mississippi," will be used. The purpose is to determine whether a rapid rate of change of range can be covered by our present fire-control system. The "Iowa" will, be run at varying speeds while under fire; thus observers will learn whether fire con- trol apparatus can meet the require- ments. The Boy's Radio By C. A. Boulton THE boy sat in his room one night Just listening with all his might. His mother called, but he would not go Because he loved his radio. He gets the stations far and near; And everything comes loud and clear Except the warning voice below — Which does not come by radio. His mother goes up to his room And incidentally takes the broom. But here's one thing she didn't know: It's dad who has the radio. An hour goes by. The lunch is cold, And yet we don t hear mother scold, For she has let the luncheon go To listen to the radio. . . The second test will be for the 14- inch turret guns of the "Mississippi" and will represent maneuvers which might be expected when two ships are engaged, where frequent changes of course are made by both vessels. The idea is to test out whether or not the "Mississippi" can keep hitting the enemy ship undisturbed by the shifts of course and whether the instruments now employed are adequate for such firing. Turret guns will also be used in the third practice, where a ship, engaged by another, makes a decided turn to right or left. The effect on the ac- curacy of fire is sought and it is also desired to learn whether it would be possible to discern such a movement quickly enough to correct the training of the guns without affecting the ac- curacy or rapidity of fire. Nig- ht Attack and Indirect Fir* The fourth event scheduled will simulate a night attack. It will be the most spectacular, probably, as it in- cludes the use of searchlights, star shells, and other artificial means of illuminating the moving target-ship. Here, again, only the 5-inch rifles will be employed. In the fifth and final gunnery ex- ercise, a test of the use of 14-inch guns for indirect fire is planned. It will be the first time an effort to study the desirability and practibility of this method of fire has been tried by ships at sea. In clear weather this would mean a range of over 25,000 yards, but in hazy weather or over a smoke screen, this method might be used at a range of about 15,000 yards. In this maneuver, aircraft will be used for ob- servation and spotting, radioing con- stantly to the "Mississippi." It is understood that no aircraft will take an offensive part — that is, no bombs will be dropped as was the case a year and a half ago in the maneuvers off the Virginia Capes. As it is not desired to sink the "Iowa," special projectiles will be used. They will have very thin walls and supersensitive fuses. These shells will be filled with high-explosive charges. It is expected that when direct hits are made they will all ex- plode on the armor plate of the vessel and break up rather than penetrate her. Since the World War the "Iowa" has not been kept in the same condition as a vessel in active service. She is far from the last word in warships and her armour and water tight compart- ments are not modern. It is possible, therefore, that if she is hit many times at weak points, she mav sink, Digitized by Google

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RADIO WORLD Chief Characteristics of the W-D 1 1 WHEN a man has dabbled in radio a certain time, he wants to "roll his own." One of the great stumbling blocks is whether he will use the regular 6-volt tube or the new lj^-volt (W-D 11) tube. This little tube, through the agency of being a wonderful detector and a stable amplifier, is rapidly claiming the at- tention of the entire radio world. Due to the fact that the filament is oxide coated and of low temperature, it only glows a dull red when in use. But owing to the fact that the base is entirely different from that in cur- rent make of tubes, it requires either By John Kent an entirely different socket or an adapter. The characteristics of W-D 11 were compiled by the experts of the Radio Corporation of America and are as authentic and correct so far as it is possible for such things to be. They are as follows : Filament — Oxide coated. Low tem- perature. Current consumption, 0.20 ampere. Terminal voltage, 1.1 volts. Source of voltage, standard 1.5- volt dry cell. Plate— Voltage for detector, 22.5 volts. Voltage for amplifier, 22# to 45 volts. Grid — Condenser capacity, .00025 leak, 2 megohms. Output impedance— 20,000 ohms at 40 volts plate-voltage. This little tube is very stable in ac- tion and, probably, one of its great- est recommendations is its absolute freedom from noises common to other tubes. Another recommendation one that is very necessary in these days of regenerative circuits — is its absolute stability of oscillation. It is one of the finest little oscillators on the market. Owing to the fact that they are standardized they may be used either as detector or amplifier. Radio Develops Chicks EXPERIMENTS conducted by John T. Thomas in an incubator hatchery at Columbus Grove, Ohio, have demonstrated that radio has a beneficial effect in stimulat- ing the growth and development of young chickens and produces strong and sturdy fowls. The discovery was accidental but confirmation of such , results was proved by a series of tests and experiments covering a period of several months. Mr. Thomas hatches approximately 3,000 chicks a week, requiring his personal attention almost hourly day and night With a view to relieving the monotony of the long hours of vigil he installed a wireless outfit, over which he received broadcastings for his own entertainment, consisting largely of musical concerts. It was not long after Mr. Thomas sought this diversion that he noticed that the radio programs were having the effect of lulling his little chicks to sleep. Without the music they were restless and nervous, but as soon as the instrument was tuned they became quiet, and soon were asleep. The result of the abundance of sleep and relaxation was more rapid growth, better health and physi- cal condition and stronger development. {Continued from preceding page) but the Navy Department desires that the five tests be made without any such mishap. Her radio-control apparatus is of considerable value, being the first remote-control system for a full-sized seagoing vessel in the world. Then too, future radio-control development in the Navy will undoubtedly be based upon this, the first radio warship. The "Iowa," now at Norfolk, will be towed to Guantanamo, Cuba, by the "Promethaus," and from Guantanamo will be towed to Panama Bay on the Pacific Side of the Canal. Captain W. D. Leahy, commanding the "Shawmut will virtually control the "Iowa" during the maneuvers, with Lieutenant-Commander R. F. McConnell in charge of radio installa- tions. Ensign Hertz will also assist in radio-control work. 576 Broadcasters Started the New Year On January 1, 1922, There Were About 5 in Existence. Class-B Stations on 400 Meters Now Total 25 By Washington R. Service TOTAL broadcasters on January 1 numbered 576, according to the records of the Radio Section of the Department of Commerce. A year ago there were but four or five such stations. The growth has been phenomenal and still continues, although in a less rapid degree than during the first seven months of 1922. During the month of December, 31 broad- casting stations were licensed, and 20 dropped out for one reason or another, showing a gain of 11. Of the total broadcasters today 25 are in the B class, transmitting on 400 meters, a privilege granted only to the best stations which apply for this means of getting out of the regular broadcasting band. The future of radio as a popular pastime depends to a large extent on the pending bill in Congress, especially as to the re- allocation of wave-lengths. It is of interest to all fans as by this means the ether will be cleared of much interference. But the future also depends upon broadcasters anj the great radio public of "listeners-in." What they want will probably be granted. If radio broadcasting is to become a public utility, as is predicted, the public must back it up and insist on necessary laws, regula- tions, and authority for the Secretary of Commerce to work out. Eight new broadcasters were licensed during the last week of December. Seven were licensed on 360 meters. The new stations are the following: WRAM — Robert E. Compton. and Carthage College. Carthage. Illinois. VVQAC— E. B. Gish. Amarillo, Texas VV PAW— Radio Installation Co.. Inc., Wilmington. Delaware. KFCM— Richmond Radio Shop. Rich- mond. California. WPAX-S-W Radio Co.. J. R. Shumate. Jr., Thoma'villc. Georgia. WPAV— Paul Tinetti 4 Sonn, \\ r<t Virginia. KFBA — Ramey 4 Bryant Radio Co, Lewistnn, Idaho. WJAC— The Redcll Co., Joplin, Missouri KYF — Thearle Music Co., San Die«o California.

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14 RADIO WORLD Radiograms The Latest Important Radio News Briefly Told for the Growing Army of Radio Fans GREETINGS from Vice-President Calrin Coolidg* broad- casted from WGY, in Schenectady, by use of the pallo- photophone, were heard in England, according to a cable- gram received from Arthur Brooke, 69 Renshaw Street, Liver- pool. Mr. Renshaw's cable reads : "Using an indoor aerial forty feet long, heard your program broadcast both December 23 and 24. Christmas Eve I used loud-speaker and five tubes and was able to pick up your entire program." * * * Charles B. Cochran of London, sent holiday greetings by wireless to friends in New York. To insure as prompt delivery as possible through the general holiday closing, the Radio Cor- poration of America, on receipt of the messages, phoned them to the office or home address orf the recipient. * * * Newark's WOR broadcasting station announces the reading of the new Roosevelt Boxing Rules by James J. Corbett for the benefit of boxing fans. * * * According to Secretary Denby, the United States Navy will fight vigorously any attempt to bring its radio operators under commercial Hcense. This was the Secretary's declaration fol- lowing the statement of Secretary of Commerce Hoover be- fore the House Merchant Marine Committee, urging that all radio operators, including those of the Navy, be compelled to take out licenses from the Department of Commerce under the proposed Radio bill. Secretary Hoover declared that inasmuch as the Navy Department was accepting commercial business it My Set and How I Made It By Donald W. Kleitsch 2121 East Fourth Street, Duluth, Minnesota M1 Donald W. Kleitach at bis set. rY set is a single-circuit tuner with a detector and one step i of audio-frequency. I use a graphite-pressure rheostat, to control the detector filament, and find that it gives very much finer tuning. I also use a wire rheostat for the amplifier filament, 200-radiotron tubes, and 201 for detector and amplifier. The body capacity, when tuning the condenser, gave me a lot of trouble, so I shielded it with aluminum and connected the rotary plates to the aerial. After doing this, I practically eliminated capacity effects. A phone condenser is placed across the De Forest amplifying transformer. I use a 43-plate condenser in the aerial circuit and a 2500-thousandths fixed-condenser in the grid circuit. This set has a range of about ISO to 650 meters. The cost— without tubes, batteries, or phones — was about $34. I have received Schenectady and Lockport, New York; Pitts- burgh; Fort Worth and Dallas, Texas; Denver, Colorado; San Francisco ; Atlanta, Georgia, and many others. should not be an "outlaw"- among other broadcasting agencies. That broadcasting of Sunday night sermons should not have priority over amateur transmitting stations was contended by Andrew E. McNaughty, president of the Wireless Association of Pennsylvania. * * * An interesting weekly feature of WGI is the broadcast every Saturday evening at 6:30 on the condition of highways in Mas- sachusetts and bordering States furnished by the Automobile Legal Association. This broadcast gives the motorist informa- tion on the condition of the trunk lines highways over which he is liable to drive during the coming week, and is of great as- sistance in saving time and temper over detours and poor roads. * * * Gene E. Witham, a Brooklyn lad, succeeded in picking up the weak signals from a French amateur station, located in Nice, southern France. A Reinartz tuner, equipped with a single vacuum tube, was the only apparatus used. The CW signals were heard for nearly twenty minutes. * * » Lester Drummond Payne, an old-time radio operator and a brother of the managing editor of the London "Daily Mail," -was found dead in his shack on board the Norwegian steamet "Louise Nielson." * * • It is estimated that there are close to two million radio re- ceiving sets tapping the ether lanes in the United States at the close of 1922, and that this number will increase to at least three million by the end of 1923. * * * Each Friday afternoon, at 1:30 o'clock, you will hear from WLW, Cincinnati, a lesson on the guitar. These lessons will be given by J. F. Roach and will be in the exact form of phono- graph records made by Mr. Roach for students. After the les- son Mr. Roach will play two solos accompanied by Mrs. Roach, pianist. * * * Additional weather forecasts and warnings will be broad- casted from NAT, the Naval Radio Station at New Orleans. These broadcasts, on a wave of 1,832 meters, are for the dis- trict included in Louisiana, Arkansas, Oklahoma, and Texas and comprise weather forecasts, river' conditions, and a summary of the conditions over the United States twice daily. The scheduled calls for a broadcast at 10:30 A. M. and 10:00 P. M. at 75th meridian time. * * * Where the aerial on vessels at sea has been damaged good r results have been obtained by operators throwing winding wire in spiral fashion around the operator's body and using that in the place of the aerial. * * * Play'-by-play radio reports of the Penn State-University of Southern California game on New Year's Day were handled by KDKA from Pittsburgh. The movements of the players were described over the telegraph from the gridiron at Pasadena, California, and translated by an announcer at the Pittsburgh broadcasting station. * * * KDYS recently received fifty-four telephone calls, asking for an encore of one of its program numbers. * • * In an effort to improve the programs of the various broad- casting stations, the Pacific Radio Trade Association and the broadcasters have agreed to omit mechanical music between 8 and 10 in the evening and to cut out all broadcasting between 7.30 and 8 o'clock so that fans may have an opportunity to listen in on long-distance stations. * * • England received radio messages of twenty-three American amateurs in one day recently. * * * Radio has a children's hour. From 5 to 5.30 P. M., every day except Saturdays, has been set aside at WGI specially to en- tertain children. On Monday, there are hero and adventure stories for boys; on Tuesday there are fairy tales for the little ones; on Wednesday there are animal stories; on Thursday stones of the world we live in are told, taking themes from land and sea that answer many questions in the minds of grow- ing boys and girls; Friday evening is for the girls around the Girl Scout age ; Sunday afternoon will find Bible stories and various myths and legends on the program. Digitized by Google

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RADIO WORLD II Radio and the Woman What the Great Game of Radio Brings to a Woman Who Has a Set in Her Home By Crystal D. Tector EVER since Friend Husband and I learned code, we have taken a great deal of interest in C-W fans on (he 200- meter wave. You'd be surprised what distance you can cover on the lower wave-length. I used to think that it was great to tune in Davenport on one tube; but on nights when programs are not so interesting, we always tune in around 200 meters and listen to the "sixes and sevens" trying to get the messages through and their "hooks cleared," as they call it. We have become quite expert in the code. It is really a lot of fun. * * * THE other night, when Friend Husband went to his lodge, I called in Mrs. K , my neighbor, to listen in with me and otherwise pass the time. We sat there listening in, and as my friend doesn't know code, I had to keep up on from 360 to 400 meters. About 11 o'clock, we happened to get Havana. PWX had several wonderful tenors and baritones singing some ex- tremely sentimental Spanish music. Mrs. K. and I just sat there and listened— and listened I Suddenly, the door opened with a rush and F. H. hurried in. "Say, you're a fine one!" he exclaimed, looking straight at me. "Mr. K. came home from the lodge with me and has been worrying about Mrs. K. And here I find you both listening in — and it's two-thirty in the morning." Perhaps I was really thoughtless ; but, even at that, you don't hear PWX every night in the week. * * * T WONDER when I will cease toi be taken as a radio expert A by the woman readers of this' column. This week, I re- ceived over thirty-five letters from various women, all asking me to give them advice. I think I will have to apply for a R. E., pretty soon. * * * NOW I know that I'll never get any rest. Since F. H. has put up that loud-talker with the power amplifier and the Vincent Lopez orchestra is transmitting from WJZ, all my friends want to do is come over and dance.. * * * «T WISH you all a Very Happy New Year 1" These were the ■*■ very words, with a pleasant southern drawl, that issued through the loud-speaker in my radio room. We were having a radio New Year's party and there were a number of friends present who have sett at home. "Oh, I wonder who is announcing from WHN tonight I He seems to be a Southerner!" exclaimed one of my friends who prides herself on the fact that she has such a wonderful set for DX work. The announcer had said: "This is station WGM, the Atlanta 'Constitution.' We will now continue with our program." "Oh! that can't be possible," continued my friend. "Why, I can barely hear him with the phones on. And here he is, loud and clear! Oh, my dear, how do you do it?" And the evening was spoilt, so far as my friend was con- cerned. Of course, I didn't tell her that Friend Husband had just put in a Power amplifier along with three steps of radio- frequency; but I don't like to start the New Year off wrong, so I'm going to tell everybody else and then maybe somebody will tell my astonished friend. * * « T RECEIVED a letter from a young girl in the Middle West J- While what she says is unusual, it is the old story told in a slightly different way. She says that she had an appointment to broadcast a little talk on social science from one of the large stations. She was a total stranger in the town. When she had finished the announcer, of course, told the listeners that any one who wished to communicate with the talker could reach her care of the station. The next morning she received a 1-rtter from a voung man in a neighboring town, requesting a meeting if it could be arranged. She, being a stranger and lonesome; thought it could, and asked the station operators if any of their acquaintances could formally introduce them. The introduction was arranged and — well, this happened about four months ago. Along with the letter she sent me an announcement of her engagement. Friend Husband became unduly hilarious when he read the letter. "That should teach a lot of young fellows not to meddle around with broad- casters," he remarked in his best "I-am-a-lawyer" tone of voice. But say I : "Cupid will not be discouraged even if he has to turn to radio for help." * * * A YOUNG man writes me that his sister insists he shall install 1 *■ a loud-speaker in the parlor so that music from the local station may be heard when she is entertaining her beau. The young man wants to know if this is possible. Surely; but it has this drawback: If my correspondent is of the type not satisfied to listen to one station for any length of time his sister probably will be greatly disappointed, and may have a ?reat deal to say after the "show is over." * * * FRIEND HUSBAND came home the other night emitting an odor that resembled a popular beauty shop. His nails were manicured almost to distraction and his hair was bright and glossy. After cross-questioning him the truth escaped. He visited a barber shop in New York City, and he said : "They had a radio set and the program was so interesting I simply had to hear it all ; and, as it wasn't a public lounging-room, I had to have some valid excuse, besides being shaved and having my hair cut, to stay and listen to it all ; so I had everything done except a permanent wave.'' My Picture for This Week By Crystal D. Tector 1 Kadel & Herbert) VOU will remember that, in last week's RADIO WORLD I mentioned the fact that there was a set at the American Radio Exposition made in ivory and cold. I have just received a letter asking me if 1 thought everybody "was as ignorant as that." It "got my dander," so that I went on the warpath and told Friend Husband that If he expected to Hve in peace with me this year, he would have to secure a photograph of this set so that I could convince the skeptics that sometimes when It glitters, it really is gold. Here is the photograph ! The little wires and knobs in the upper left-hand corner are miniature Jacks and plugs of solid gold, by which any combination of instruments may he connected without the trouble of rebooking the set from the back of the panel. This, of course, is a very grant Improvement as It allows any number of circuits to be tried out. The panel is of Ivory. Digitized by Googl<

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RADIO WORLD Radio's First as These

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RADIO WORLD 17 kys of 1923 Are Busy lotographs Show (Left) Pupils of the Dennlmon School, Washing- ton, D. C, who make a specialty of singing health ■ones in order to make the public for the tion of that dread Kadel & Herbert) (Above) Many radio experimenters have constructed diminutive sets, but It was always necessary to add a head-piece. B. S. Leweuen of Minneapolis has constructed an entire radio outfit m a one-piece head- set, crystal detector and tuning coil. The circumference of the instru- ment Is that of an ordinary telephone receiver and It is three Inches in length. This picture shows the set hooked up to a waste basket as an aerial. Concerts can be heard for a distance of 12 miles. *!d Photos) •cm of the steamer "MranekahdV* who established a radio anmlcarJoo between ship and shore. Their radio was heard '"■object," producing dull sounding areas in the abdomen corre- > r dneue anight for. Every disease has a certain known vibratory f' V. HUhnan (on extreme right) ie tuning in on the disease sus- ' ans. The nurse is applying an electrode to part of subject where 'falcated, this indication being determined by Dr. Clarke Francis 5*V who is shown tapping the subject's abdomen. The subject s face the geographic West when the tests are being made.

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RADIO WORLD With the DX Nite Owls Fine Record from Oregon From Artfcur W Volts ^Phones ^liliWilik— ©0— Varro- [Coup/er jj Grid Cood. IvvwJ \\TQAA, WFAA, WJAX, W 6 Volts FIGURE S rcbemaUe dsatcna of tha thraa koak-upa daacrlhad by Mr. Myara to his intorsatnnj latter and showing tha advantaga of using anty first -class I HAVE been a reader of Radio World since Vol I, No. 1, and your DX page in- terests me most Continue it. I wish the claimers of DX records would send in their hook-ups and, also, name the instruments used in them. DX records do not depend so much on the hook-up necessarily, but on the apparatus used. Any old condenser or phone will not do. I am sending you three hook-ups out of the hundreds that I have, which include the hook-up of Mr. W. Miller in various forms. The following are used in No. 1 : Remler- Giblin coils; Thordaison condensers, J001 mfd.; U-V 201 or RAC, 3 tubes; also W D 11- A. I use an automatic filament- current adjuster known as the Am peri te. It eliminates all rheostats. I also use variable B battery and Baldwin phones and radio- duct wire. A. C. H. Sharp Tuner Dials are used on all condensers. They give a one- thousandth part of an inch turn. No hand- operated condenser and vernier combined will give such fine adjustment. The same apparatus is used in No. 2 and No. 3, except No. 2 has a triple coil mount- ing, three Remler-Giblin coils, and an audio- frequency transformer. I used an Amer- Tran transformer. They go fine with radiotrons. In No. 3 a vario-coupler is used. The sec- ondary is used on the plate circuit Only first class instruments will give first class results. Remember that I The only dials that should be used are those that give a "hair line adjustment." The second hook-up will, I am sure, prove very interesting. Let us hear from you radio fans. a a a On a One-Slider Crystal From Caorg* L. Marital. BS Bsrarty ~ " Wis. I HAVE a one-slider crystal set and I think it is working fine. Here are my stations. I only have a chance when the four local stations are silent: WAAR, WCAY, WHAP, WIAO. WOC, KYW, WGY, WHB, WWJ, WDAP, WBAP, KSD, WLK, WLW, ZXY, WCX, WMAK. WGM, WAAF, WBU, 9-CIW, WSV. Also "The Star, Kansas City (WDAF), and the Horlowa Radio Co., Rock Island, 111. (not listed). Any one wishing my diagram please write. a a a Antenna in Attic From Ralph E. TayVn-.J^Eaat Huran, Ana 1HAVE been greatly interested in the results the "radiophono" has obtained and published in Radio World. I have a set of my own construction. I use the stand- ard honeycomb hook-up. The coils are tapped, and, consequently, home-made. I employ one tube. I have heard stations from over the entire country — from Texas, Oklahoma, California, Massachusetts, and about twenty-one other states. I get PWX, Havana, Cuba, frequently; also several Canadians. The above record is quite common on an ordinary amateur antenna. My antenna, however, is situated in the attic, which is covered by a tin roof. The antenna con- sists of 4 strands of No. 12 copper, 30 feet long. Using neither antenna nor ground, I re- ceive WWJ and WCX quite audibly; also WGY and KDKA very faintly. Several times I have hooked onto the springs in a bed for an antenna. This made a very good substitute, gathering in music from WGM, WDAF, and several others. If the fans cannot tune in to this please tell them to continue to send in their results. a a a With Straight Regenerative- Circuit From J. J. Cannon, Manch Chaak, Fa. HAVING read with interest the letters of the broadcasting fans published in your valuable paper — and some of them Digitized by

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RADIO WORLD 1* With the DX Nite Owls (Continued from preceding page) have me beaten for long-distance reception — I am sending you my list. Local stations : WWZ, WBAY, WEAF, WJX, WGAC, New York; WOO, WIP, WNAT, WCAU, Philadelphia; WRW, WGY, WHAM, WMAC, WHN, WHAZ, WRP, 3-XW, WBAK WBAG, KDKA, KQV, WJZ, WOR, WBZ, WNAC, WGI, WHK, WLW, WWJ, WWI, WGR WMAK, WBAF, WVP, 2-XKA, WSZ, WMAF, WBAK, KOP, WJAX, WP1. Long-distance stations: WOH, WLK, Indianapolis; WCAY, WAAK, WIAO, Milwaukee; KYW, WMAQ, WJAZ, WDAP, Chicago; WLAG, Minneapolis ; WHY, Martinsville, Illinois; WMAT, Duluth; WCAP, Decatur, Illinois; WOC, Davenport, Iowa; WHB, Kansas City; WEY, Wichita, Kansas; WCK, St. Louis. WEY is longest distance from here — 1,400 miles. I am using the straight regenerative-cir- cuit with .001 mfd. condenser on ground lead. Aerial is 100 feet long with a 50- foot lead-in. Using two steps of audio-amplification, WMAQ, Chicago, on Christmas Eve, was heard very distinctly on a loud-speaker, which, by the way, is only a Baldwin phone with Lily horn attached. * * * Uses a Wave-Trap From W. D, Ready, 42M Holmea Street, Kaneaa City, Ma I HAVE accomplished no great distances, but this list of stations I have heard since December 1, and most of them con- sistently, with a honeycomb regenerative set and two stages of amplification: WBAP, WSB, WPO, WAAE, KYW, WCX, KSD, WJAX, WAAJ, WDAB, WFAA, WGM, WDAJ, WLAG, WAAF, KFAF, WBL, WDAP, WDAW, WNAV, WJAR, WAAP, 9-YQ. 19-DKO, WPA, WHAS, WNAD, WPAC, WJAZ, WOC, Schematic of hook-up by Mr. Ready, lu to the No. St coil and .til con- i a "wave-trap" to eliminate any elation not wanted. WWJ, WOAI, WAAC, KYI, WOS, WJAT, WMH. WMAB, KDKA, WDAO, 9-ZAY, WKY, WFAS, WGY, WEAF, KOP, 9-ZAF, WIAO, WGAQ, WMAP, WIAC, WGF, WLK, WJAP, WFAV. All of these came in sufficiently strong to be heard all over the first floor of my home. There are very few of these I have not heard several times. I am also using an apparatus called the wave-trap, used to eliminate stations I do not care to hear— a hook-up without amplification. ♦ * * Disconnected Aerial and Ground From Clarence Milanio, Enflewood, N. J. I AM pleased to tell about my set, which I constructed a few months ago. It consists of a triple-geared De Forest type with a 2-variable condenser, series-parallel switch and 2 stages of amplification. Having obtained good results, I disconnected my aerial and ground and am still copying WJZ, WOR, WEAF, and others. I know code— Morse and Continental — and have copied POZ, MPD, MUU, and up to 18,000 meters, using 1,000 and 1,200 duo-lateral for the high-wave stations. I also copied WHN without an aerial. » » » Another Challenge for Mr, Lindstrom From Mike Podhorn (Old Timer), Box 19, Wood River, 111. IN Radio Womjj, No. 37, dated December 9, 1922, I noticed that Arthur Lind- strom (Baraboo, Wisconsin) heard from coast to coast and from border to border with his equipment of a one-step amplifier with 45 volts on plate, using Cunningham tubes and a Thordarson transformer. His record of receiving long distance takes the prize. I have quite an expensive set and, although I heard dots and dash from half of the states in the Union, I have not heard any music from any western station. If Mr. Lindstrom's record is correct and true I would advise him to obtain a patent on his set and put it on the market I believe it would reap him quite a fortune. I for one would like to obtain a diagram of his set as I would like to put one up and try my hand at long-distance receiving. I have been in the game nearly three years; and, although I do not claim to know it from A to Z, what I do know is a great help to me in putting up radio sets for my friends. Come on, radio bugs, and let's hear what you have to say in regard to Mr. Lindstrom's record of long-distance re- ceiving! Best 73s. * * # Consistent Long-Range Work From C W. Good*, Thornton, Washington T HAVE a home-made regenerative set *• with two stages of audio-frequency. Have heard WGY, WEAF, WIP, KDKA, WSB and WGM — each three or more times during the last two weeks — also numerous stations in the Mississippi Valley. There are three sets in this town, all alike, that have accomplished this. The others have received some eastern stations that I have not. We get Fort Worth, St. Louis, Kansas City, Davenport, Minneapolis and Winni- peg—some of them every night. If any one can show a set that will give more consistent long-range work than this tell us about it. * * » Seattle Sends In One From E. L. Gerry, 3M4 Denamore, Seattle, Wash- ington F HAVE a long-distance receiving record * to report. On December 11, 1922, at II p. m., I heard 6-XB, the Mercantile Trust Company, San Francisco, California, music and speech QSA. My set consists of one U-V 201 tube, single circuit, honeycomb coils, 40-volt plate, 3}4-volt filament potential, ground connection, no aerial, series and parallel primary-condensers. * « « Simple Set Works Well From Thomai F. Corteee, lit Wert Liberty Street, Louisville, Kentucky,, WING read other records send in, I will send mine. On an aerial 4 feet above a tin roof, and 100 feet long, with a 15-foot lead-in and 20 feet high, I have received the following stations: KDYX, (Continued on page 27) MAGNAVOX Pioneers in the Radio field IT was in 1913 that the Magna- vox electro-dynamic receiver made its first public demonstra- tion, when telephone communi- cation was held between Denver and New York— a revolutionary advance The rise of radio broadcasting found Magnavox apparatus already perfected and in success' ful use. R-2 Magnavox Radio with 18-inch horn THIS instru- ment is in- tended for those who wish the ut- most in ampli- fying power : for large audi- ences, dance halls, etc., but requires only .6 of an am- pere for the field. Price, $85.00 R-3 Magnavox Radio with 14-inch horn SAME in principle and construc- tion throughout as Type R-2. Is ideal for use in homes, offices, amateur stations, etc. Requires one ampere field cur- rent from your filament battery. Price, $45.00 Magnavox Power Amplifier— Model C CAN be used with any "B" Bat- tery voltage which the power tube may require for best ampli- fication. AC-2-C, 2-Stage AC-3-C, 3-Stage $80.00 $110.00 The facilities and experience back of each piece of equipment bearing the Magnavox trade mark are unrivalled anywhere in the world. Magnavox products may be had of good dealers everywhere. Write to us for ilhutrated booklet The Magnavox Company Oakland. California New York Office: 370 Seventh Ave. Digitized by Google

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20 RADIO WORLD Latest Radio Patents V This circuit is known u the "antenna/* or open, circuit and, as usual, is capable of adjustment as to resonance for high-frequency electromagnetic waves of dif- ferent lengths which are transmitted from a transmitting station. This adjust- ment simply means that a proper Talus of capacity (m microfarads) and a proper value of inductance (In henries) has been attained to allow the passage of waves of predetermined frequencies. Another Static Killer No. M»,«K. Patented December U, UZL Henry M. Williamson, Chicago IN his specifications Mr. Williamson claims an apparatus having an audio- frequency amplifier, or a cascade of such amplifiers, employing a method for isolating and excluding static interference from any source. It is also claimed that it will pre- vent oscillations in a thermionic amplifier. It is also claimed that it will provide a means, located between the detector and the receiver, which will completely filter out static. * * * New System of Modulating No. 1,4J»,U4. Patented December tt, UB. Patentee! Leon J. Slvian, East Orange, N. J. MR. SIVIAN'S is an invention to pro- vide a high-impedance control-element associated with the oscillatory circuit of an electronic oscillator in order to prevent variations in the frequency of the oscilla- tions produced ; also to produce an arrange- ment whereby the electromotive force impressed on the input circuit of a ther- mionic device used as an oscillator is directly under the control of a transmitting device. A large class of thermionic oscillators contain an electron-discharge device having Figure 1 illustrates diagrammatically signaling system in which an oscillator produces oscilla- tions of an amplitude determined by the value of of thermionic impedance, and supplies oscillating energy to a transmission circu't. Figure 2 illus- trates a modification of the oscillator arrangement of Figure 1 applied to a radio system. Figure 3 illustrates a modification of the circuits of Fig- ure 2, in which the thermionic control impedance is replaced by a condenser transmitter. Figure 4 Illustrates another modification in which the thermionic control Impedance is Indirectly Intro- duced Into the control circuit. three elements — a cathode, an anode, and a grid, or other impedance-controlling element — associated with an oscillatory circuit in such a manner that a portion of the oscil- latory circuit supplies a variable electro- motive force to the input, or grid-cathode circuit, of the electron-discharge device, and the cathode-anode, or space-current cir- cuit, of the discharge device in turn impresses a variable electromotive force on the oscillatory circuit. It is quite common to connect the input circuit of the electron- discharge device, or tube, to the terminals of a condenser in the oscillatory circuit, or across part or all of an inductance in the oscillatory circuit. Moreover, the oscillatory circuit may be closed or open, as in the case of an ordinary-tuned antenna — the antenna conductors and earth acting together as a capacity element. The electromotive force impressed by the oscillatory circuit on the input circuit of the tube is that which normally exists between the points in the oscillatory circuit to which the grid and cathode are connected. According to Mr. Sivian's invention a variable coupling is employed between the oscillatory circuit and the input circuit of the electron-discharge device. A high- impedance shunt-path is connected to the two points in the oscillatory circuit, to which the input circuit-elements are ordinarily connected, and the input circuit elements are connected to two points in this im- pedance shunt-path. The relative values of the portion of the impedance between the points of connection of the input circuit and the portion outside of these points can be varied by control elements, varying the fraction of the electromotive force. * * * A New Vacuum Tube No. l.OMe*. Patented December U, U2Z. Patentee! Lawrence B. Spengeman, Jersey City, N. J. THE object of Mr. Spengeman's inven- tion is to provide a filament support which, in addition to supporting the filament, will apply sufficient tension to prevent vibration, and will also maintain the proper space relation of the filament with any other parts of the lamp which may be positioned therein. It is particularly applicable to vacuum tubes in which a plurality of elec- trodes are used, such as a filament, a plate, and a grid, the space relations between which must be maintained constant in order that the proper operation of the device will result The invention comprises an insulat- ing block positioned near the upper end of The large free curve of the supporting wire affords greatei resiliency and mora ready ad- justments. the lamp, from which extends a spring wire in a curve to a point beneath the block where the spring is connected to the fila- ment. Between the point of the block from which the spring wire extends and the point of connection with the filament the spring wire is given one or more turns in the form of a pigtail twist to produce elasticity. ♦ * » To Avoid Large Inductance No. MSUSt, Patented December 12, Its. Patentee: William E. Beakes, New Orleans, Louisiana IT is well known that in order to receive signals of a given wave length the an- tenna of the receiving station must be tuned so that its natural wave-length corresponds more or less closely with the wave length of the incoming signals, and likewise, since the wave length of the outgoing signals at a transmitting station depends on the natural period of the antenna, the antenna is made adjustable in such a manner as to vary its natural period in accordance with the wave length to be transmitted. Heretofore it has been common practice to tune the antenna so as to give it a desired PC 71 natural period; or wave length, by varying the factors of inductance or capacity. The object of Mr. Beakes* invention is to avoid the necessity of using a large inductance, or capacity, in the antenna for the purpose of adjusting it to desired wave lengths, and, thereby, to increase the efficiency of the an- tenna both when the apparatus is used in a transmitting or receiving system. The ad- justment of the antenna to a given length is effected in part or in whole by increasing, or decreasing, its operative length, or the length of its conducting parts. By this means the radioist is enabled to do away with the use of large inductance, or capacity, in the antenna circuit. By adjusting the antenna to the desired wave length in this manner, Mr. Beakes claims, a much stronger signal is received or transmitted than would be the case if the adjustment were provided

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RADIO WORLD 21 Secrecy in Radiotelephony Seems Assured Combination of Radio and Land Telephone Is New Wonder. Experiment Made on High-Tension Wires Carrying 70,000 Volts Proves Successful RADIO PANELS »"rt4" 1M M"a*4" Ul HMHiffwtwm^ MMtal tins NlMtttf* Aqmb viiMi PAGESON^CTMPANT^ ^ BALTIMORE— The successful trans- mission of voice over electric power lines carrying 70,000 volts by means of carrier current, a new development of radio, is announced here by the General Electric Company. The tests were made over the high-tension lines connecting the Highlandtown sub- station of the Pennsylvania Water and Power Company here, with its hydroelectric plant at Holtwood on the Susquehanna River, a distance of forty miles. Conversa- tions were carried on under every possible condition that might occur on a power transmission line, such as short circuits, grounding and broken wires. The apparatus by which the transmission of voice is made is similar to a radio out- fit, having vacuum tubes, batteries and other appliances. Instead of radiating waves through spaces in all directions as from a broadcasting station the voice waves are kept concentrated about the electric power lines, thus insuring privacy and direction of signals. Quality at Speech Much Better Than Br Land For power companies the carrying current system has many advantages over the land- telephone, for so long as there is a single transmission line in operation communica- tion can be carried on. Ordinary telephone wires, which are many times smaller than the high-power electric lines, are generally the first to suffer during a storm, whereas transmission lines are seldom affected by even the most violent storms. In the tests made here the quality of speech was much better than that obtained by a land telephone over the same route. The conversation was free from hum and other noises which are usually experienced when a telephone line parallels a high-power electric system. Carrier current, in addition to insuring privacy in communication, has other advan- tages over radio. Static, fading of signals, and interference from other stations are entirely eliminated. Government broadcast- ing licenses are not required, and it does not require a licensed radio operator. A small switch connected with an ordinary telephone instrument does all the work. By moving this switch upward a bell is rang at the other end of the line. The switch then automatically returns to neutral or listening position, and conversation begins. The apparatus is in operation only when a coversation is in progress, _ the telephone hook holding the receiver acting as a switch for the set. Equipment Constats of Detector and Two Ampli- fier Tubes When the receiver is raised a small motor generator is started, supplying 1,000 volts direct current. This is put through two 50-watt vacuum tubes and converted into high frequency alternating current of 15,000 1923 Will Not Be Complete! Without a Tear'* Subscription to RADIO WORLD (52 numbers) $6.00 Add $1 s 7 ear extra for postage to Canada and foreign countries. cycles. This voltage carries the voice signals from the telephone into a wire 1,000 feet long, leading from the station and parallel to the transmission lines. Traveling at the speed of light, or 186,000 miles per second, the voice is received at the other end much the same as radio broad- cast signals. The equipment consists of a detector and two amplifier tubes. Tubing is not necessary as the wave-length and other characteristics are always the same. Since carrier current travels on a wave- length of 15,000 meters it is removed from any possibility of interference from radio broadcasting stations. Tell Us Tour Radio Troubles OCR ADVICE MAT HKLF TOP ftlrc full pan Italian. BtJ»w W iMtiMMtt* ImsI a^aaa1l#ae^Ba> fteasaeh — -* I aaimiafc anf enanslahl Hat AlaBenaAann HeilllMIt **T^* NaVal luMfJIaa H ■aWtasJ ■ PJI IRfMa tottM* ivtfw^fnwJ ink Ml t% IftiftvtAMl* Baatsas Ms. sad asdrimd ataaaa* saw RADIO INFORMATION BUREAU (17 First Ave. Me. PATE A Real Task TT is apparent that the task of the radio *■ broadcasting director is to find music and speech of a character that will bring real information and pleasure to the greatest number who listen in. But when the pro- gram you get doesn't quite meet with your approval always remember the many prob- lems that the poor director has to over- come. Next to running a grand opera the running of a broadcasting station is the best test of the mental stamina of humankind. When a man tells his wife, who is hold- ing supper for him, that he wants to "listen- in" just one more minute he is usually pick- ing a minute half an hour away. To the Man with an Idea I offer a comprehensive, experi- enced, efficient service for his prompt, lesnl^protection, and the Send sketch or modi tion, for advice si to cost, search through prior United States patents, etc. Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable me to sccurately advise clients as to probable patentability before they go to say expense. Baatlat 1 rmlutble Information, and form far Drapsrlr. dlaclaaJlK four Idas, frsa an request. Write taoaj. RICHARD B.OWEN.eets 32 Owe* Bellslst. Waaalsstas. 0. c. tt7l-P Wsahrartft Bids.. Nt» rat* city WALCON Radio Transformers loop — perfect reproduction. Mo CAN BUY Frequency Brings in distant stations distortion. THE BEST YOU WALCON Transformers are teetrd ai adapted for use with W.D.ll tubes. Four new hook-ups, Including a new without charge with each transformer. Price, $4.00. We pay postage. Dealer* and jobbers : Write lor our attractive (ale* proposition, backed by national advertising. Manufactured by THE RADIO CENTRE, 2 W- Broadway, N.Y., N.Y. DELICATE SOLDERING Both the manufacturers' and amateurs' problem on all fine work It readily solved by the instrument constructed for this particular purpose. THE POST SOLDERING IRON Platinum Heating Unit— Interchangeable Tip— Universal Current $6.00 From Your Dealer or Write Awarded Certificate of Excellency, N. Y. Evening Mail Radio Institute POST ELECTRIC COMPANY, (Div. 509) 30 E 42nd St, New To* MM Broadway New York, N. Y. REPRESENTATIVES WANTED! iff iubnvcnptioaa rep ret* the cou n try. Send *j RADIO WORLD. MM Broadway. New York qgg b RADIO WORLD wants yonag hustling subscription represents til aa in every l*eta*7 and KS buainrat concern t taroout the country. Send IS yss^aaaae^aaaj

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22 RADIO WORLD Adrertitiaf Rates, Display, $5.00 per iaeh, $150.00 per page Radio Merchandising Classified Qqick-Action Advertising, 5 eeats per word Telephone Bryant 4796 1 An "Ad" Plan That Hit T Radio Distributing and Auto Supply Co. TEL. COLUMBUS tSM M West Nth Street RADIO WORLD, MM Broadway New York atjr. New York, December 2tth, 1*22. Gentlemen:— In starting our bus in eat a» a re- tail distributor or radio goods, the writer had rtiaements in RADIO WORLD, cted with another company, and waa so Imps 1 with your pulling power aa an adver- tising medium that the suggestion waa made that wa advertise only in RADIO WORLD. Our plan has been, aa you know, to take a column one week, giving aa itemized list of our offerings win prices, and on the following week to take but three- or four-inch space, mentioning but one or possibly two special items. Although our store has not a particularly good location, our advertising haa not only proved highly profitable but has resulted in sufficient mail order business alone to give us a handsome profit from our advertising in RADIO WORLD. take pleasure in tailing you that RADIO WORLD to be a most profitable advertising Very truly yours, RADIO DISTRIBUTING * AUTO SUPPLY CO. B. K. OWEN. Heard at the Radio Counter A Conversation between Customer and Radio Clerk Part X T-TELLO, O. M.l Did you get to the Amer- ican Radio Exposition, last week?" "I most surely did. I wouldn't have missed it for a new storage battery!" "Say, speaking of storage batteries, is there any advantage in the storage B batteries I saw advertised there?" "Well, I should say so. Have you ever had a perfectly good message lost just because there was a terrible lot of tube noises that sounded like static?" "That very thing occurred to me only the other night. I was listening in to WOX. Suddenly there was a terrible noise. I blamed it on static; but I thought, later, that this time of the year is kind of late for Old Man Static to be so noticeable." "Well, if you had of analyzed the trouble, you would have found, probably, that due to chem- ical1 action, there was a heavy battle of elec- trons in your B-battery circuit. Now, if you had used a storage battery of the same voltage, you wouldn't have lost that concert." "That sounds interesting. Do you happen to have any in stock?" "We just received a fresh stock, this morning, all ready for use. All you have to do is pour in the electrolyte and connect it up. You will need a rectifier, also, if you have alternating current at your house." "Doesn't it cost a lot to charge such a high- voltage battery?" "Certainly not! You can charge your battery about every other month or so at a cost of about from three to five cents." "I feel that I had better purchase one of those batteries." "Here it is, O. M. The electrolyte is in a separate bottle. Do you want the rectifier also?" "Surely." (To be continued) New De Forest Reflex Set HE new D-7 Reflex Set of the De Forest Rauio Telephone and Telegraph Co. is shown in the accompanying illustration. This set, we are told by one of their eastern distributors, Radio Stores Corp., was recently perfected. It permits long distance reception on an inside loop through the agency of three steps of radio-fre- quency and two steps of audio-frequency, on only three tubes, and nils a want in circles where such a circuit is needed, but where the old type of circuit, using six tubes, is impossible on ac- count of upkeep and cost. The signals are rectified (detected) through the agency of a jar-proof crystal detector, which is one of the features of the set. Although primar- Photograph of the new De Forest Reflex set showing the collapsible loop. Signals are rectified by a Jar-proof crystal detector, ily developed for loop reception, it can just as easily be used with antenna and ground. This is accomplished by having the loop on a jack. Thus when the loop is plugged in through the agency of a double-circuit jack, the antenna and coupler is disconnected and the loop is tuned with the condenser which tunes the secondary circuit when the set is used with the antenna. The loop is collapsible, and the entire set may be put in operation at any time and place by simply connecting the necessary batteries and inserting into the loop. The fact that it is freely operated on either loop or aerial make it possible to use it in a district where there are many phone and spark stations, because of the fact that it tunes very sharply. Coming Events The editors of RADIO WORLJ win gladly u news Items of all s»mtsmnla>ed radio and «Po-««. *~P - P— * SECOND NATIONAL RADIO EXPOSITION, direction International Trade Exposition Co., Chicago, January 13 to 20, inclusive, 1921, George A. King, director of publicity, 417 South Dearborn Street) Chicago, M. PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial. New York City. Open from September, 1922, to May, 1923. SECOND DISTRICT RADIO CONVENTION, Hotel Pennsylvania, New York City, March L 2, and 2, 1923. FIRST UNIVERSAL EXPOSITION OF IN- VENTIONS AND PATENTS, Grand Central Pal- ace, New York City, February 17 to at, sBshujiva, 19M. New Firms and Corpora- tions ( The Arms and corporations mentioned in these columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Linquest Electric Co., Jamestown, N. Y., has increased its capital stock from $15,000 to $75,000. Commonwealth Mica Corporation, Wilmington, Del., mining, $1,000,000. (Colonial Charter Co.) United Radio Publicity Corporation, $500,000; Herald G. Wilson, Frank C. Mooney, Camden, N. J.; Charles C. Mooney, Philadelphia, poration Guarantee & Trust Co.) (Cor o New Loud-Speaker NE of the best indications that radio is be- coming more and more popularized is the fact that more and more loud-speakers are being put on the market. The entire family now wants to listen in. The Atlantic & Pacific Radio Com- pany, of New York, has just recently brought out a loud-speaker made of a special alloy of their own. The company also claims that the instrument owes its unusual qualities of clarity and tone to the peculiar acoustic properties of its design. Radio Now a National Problem SECRETARY HOOVER declares the tremendous growth of radio in recent months has made it a national problem. He estimates there are now 21,065 sending stations in this country, the major portion of them — 16,898 — being amateur. In addi- tion there are 2,762 on ships. Of broadcast- ing stations there are 576 of Class A and 25 of Class B. Interference, he says, is largely in the broadcasting stations that send oat news despatches and entertainments of various character. While the total of these is around 569, it is variously estimated that the receiving stations number 1,500,000 to 2,500,000. The interference, he states, runs largely in "the 600 to 1,600 wave-length field, which is reserved for the army and navy." This reserve of wave-lengths should be open to the public, Mr. Hoover added. Club Notes THE Mt. Pleasant Radio Club is located at 3215 East 118th street, Cleveland, Ohio. The officers are: E. Sherring, presi- dent; D. Bluff stein, secretary; H. Abrams, treasurer. The Marconi Radio Club is in active operation at 125 North 6th street, Mon- mouth, Illinois. Lloyd Sandy, president; Charles Bisher, vice-president; Lawrence McVey, secretary-treasurer. Meetings are held at high school every Wednesday night at 7 o'clock. DEALERS Take adtantage of the New York Market. Sand oi your radio needs. We are Jobbers and distributors for the largest manufacturers of standard product* CLARK A TILSON 1 East 42nd Straet, New York City Our 1923 price list should interest you Subscribe for RADIO WORLD. |&00 a year, $3.00 six months, $1.50 three mosrths. Digitized by Google

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RADIO WORLD Answers to Readers Schematic diagram of the Reinalts hook-up requested by Mr. C W. Stewart, Mempbia, Tanav, and fully described fat this department. 75 it possible to use the V/i-volt dry-cell tube in the hook-up published m Radio World, No. 30, dated October 21, by Harold Day in his article, "One-Tube Regenerator Hook-Up for Loud-Signals" f I have a crystal set, but wish to construct a more powerful receiver.— W. G. Miller, Ballston Spa, New York. Yes. This tube may be used in this cir- cuit with very good results. * * » Advise me if there is a circuit using radio- frequency in a regenerative set, but used before the tuner. By that I mean using it between the aerial and the tuner instead of , between the tuner and detector.— James E. Mac Donald, Boston. , We know of no such circuit We do not understand why you desire to use such a circuit as no advantage can be attained. * * * / contemplate building a radio set and would like a little information regarding a set capable of receiving over 500 miles. Just what parts are necessary to build such a sett How many tubes may J use with such a sett— William. O. Philips, "Sun," West Virginia. We refer you to the sets described in this lumber. All of these sets are fully described, and have been tested and found 0. K. The number of tubes used depends on how many stages of amplification you wish to utilize. If you are using only audio-frequency it is not advisable to use more than two or three stages at the most as the tube noises in sets using more than that completely overbalance the advantages. * * * Publish a diagram of a set using 3 tubes similar to those being used to give 2 stages of radio-frequency, detector and 2 stages of audio-frequency. — Walter D. Kampton, Santa Barbara, California. We understand that you want a hook-up using 3 tubes in place of the - usual tube- circuit using 5 or & See the article on page * of this issue of Radio Would by Frederick J. Romford. Publish the original hook-up of the Rein- arts circuit, also constructional data on the inductance itself.— C. W. Stewart, Memphis, Tennessee. The diagram you request accompanies your answer herewith. The tuner consists of a spider-web in- ductance of 85 turns of No. 26 S. C. C wire. The spider web has 9 spokes, and the core of the coil is 2yi inches in diameter. The complete coil, when wound, is 5 inches in diameter. Wind 45 turns on the form and then cut the wire. This is the plate winding and should be tapped at 15, 30, and 45, as shown in the diagram. Then start the antenna winding directly on top of the first and tap at the 2nd, 4th, 5th, 6th, 7th, 8th, and 9th turns and bring out the 10th tap for the ground and condenser tap. Then the winding is continued and taps are taken off for the grid coil at the 26th, 33rd and 40 turns. This coiL if carefully wound, and not shallacked will work very efficiently from 150 to 370 meters, which is sufficient for most all the work you want to cover. This tuner was designed primarily to cover C-W work on short waves, but will work on phone. * * * 1. Publish the panel layout for a 3-circuit regenerative receiver with detector and two stages of audio-frequency amplification. 2. Doe's a U-V201 function as well as a detector as a U-V20Q if properly hooked upt 3. Are variable condensers absolutely necessary in such a circuitt — Kenneth H. H. Jones, London Mills, III. 1. A suitable panel layout is published in this issue of Radio World. See the article by Mr. Cranby Meyers. 2. A U-V201 will not work properly as a detector. It is primarily a hard tube, and is intended for amplification. You had better use a regular U-V200 and save yourself trouble. 3. Due to the fact that you use variom- eters, variable condensers are not absolutely necessary in this circuit It has been found to function better in long-distance work with the least necessary capacity. It is better to tune your set -with inductance than capacity. * * * 1. Is it possible to use the Western Elec- tric V-Tl and V-T2 in a receiving set, using the V-T\ for detector and the V-T2 for am- plifiers? 2. Will they give as good results on a three-honeycomb-coil unit as the regular tubes? 3. Can they be used for radio-frequency amplification? My radio-frequency embodies two variometers and a variocoupler. '' 4. Will a 6-volt A battery operate these tubes efficiently? — Ernest Chartier, Mon- treal. 1. Yes. These tubes function extremely well as detector and amplifiers. 2. Yes. They will give as good results as the regular tubes. Besides, the V-Tl are not critical and operate on low-plate voltages. Sometimes it is not necessary to supply more than sixteen volts for their efficient operation as detectors. 3 and 4. They may be used for radio-fre- quency amplification and may be operated on the regular 6-volt storage battery. The filament of these tubes being oxide-coated, they will not light up bright. They generally operate at their best when the filament is Just a deep cherry-red. Do not make the mistake of trying to burn these bulbs too high. * * * 1. Is it possible to use the W-DU 1J4- volt tube, using 40 to 45 volts on the plate, as a detector or amplifier in the regenerative set described in Radio World No. 29, dated October 14? 2. Will they also work with the circuit I am enclosing? 3. Is any rheostat O. K. for their proper filament adjustment?— R. L. Hilton, Water- ville, Me. 1 and 2. The W-DU is a good amplifier and detector and will work admirably in any circuit It is not a very efficient radio- frequency amplifier, but, in both circuits you mention, will work efficiently. It is only necessary to put 22 54 volts on the plate of the detector, but the amplifier needs 45. 3. While any rheostat will do, we advise the vernier type for fine adjustment in tun- ing in the DX boys. American Radio Stores ■Mb OrooJt New W, D. U-Tuba Sat All Battariea. Inside Ux7. CoMoa Contact. Complete with take and SPECIAL, $30.00 ad gat DX. TUBE SET i mutt 1 W. D. 11 Socket 1 W. D. 11 Tuba 1 Grid Leak Condenser 1 "B" Battery. ZZ% voha 1 "A" Battery, dry call 1 Variocoupler Wire for Hook Up Free ft-90 l_rW, IfecUK <p|U= t*5t Murad Frequency Transformer niA tut C.N Murad Frequency Transformer Til SM S.M Auth Headsets JJS Baldwin Loud Spealrinr Units US We carry Baldwin Headsets and Brandos Matched Tone Sets. Also a complete line of all Guaranteed Radio Supplies at lowest prices in the city. American Radio Stores lay Fulton Street (audi orders) lttT Broadway Digitized by Google

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24 RADIO WORLD EACH VARIOMETERS VARIO-COUPLERS Tkm InlruBMb, Masartsly mwM aa* sear. sews*, art serfett l« wattnttttoa u4 sailaa. AM aarto era marata. Easily smusIs* sa sees), {mkr jrlaniy bas mm* law. J/ II* ar U" ssaTt. taeitlN t»«l»a rsass III la «*• enter*. WILEY VARIOMETER COMPANY Z3ZS t*. Caatral Pa. A». CHICASO, ILL. Radio Seeks Standardization Manufacturers and Dealers with High Ideals for Future Plan Intensive Work for Steady Output OVER four hundred attended the first general meeting of the Radio Trade Association, composed of manufac- turers, jobbers and dealers in the industry, at the Grand Central Palace, during the American Radio Exposition Week. The Radio Trade Association is national in scope and looks toward the development of the radio industry through the standard- ization of radio products, the control of f* rCvcrilTV REAL CABINET TYPE **0 QC LOUD SPEAKERS ^O.OO —^■oasaV Nat J not a naunw ham built Into ■ raWnrt. afSl^ai BeaoHfnl. rampart. TUB TOMB OF FINE CABINBT m?*^M mONOUBAPIIS. Make your two-step art a IIOMB BNTBK- V TAINER. All 8PIROI.A8 are af I ha baat re* »t ruction, with ^■asa?*^ Hor, robbed flalahea and are absolutely guaranteed. 8Plnol-A DUPLEX— Usee any headaet Satin black (DB) On Ian, fS-SS. Oak (DO) or Mahogany (DM) flnleh, 9AM. 8PIROLA SIMPLEX— Dm Baldwin or other unit Black (SB). Oak (SO). Mahocanr (SM> nnlah. aama prlcee aa DUPLEX. 8PIROLA CONCERT — Complete whb built-in unit and cord. Oak (CO) or Mahocanr (CM) flnleh, $11 I*. At Dealers or FoatpaM (O. O. D. If Preferred) U H. DONNEI.L MFO. CO.. Dept. B. Bo* 7*. ANN ARBOR, MICH. Praden Reliable Radio Specialties for Good Results! Phono-Phase Permanent Radio Detector The only fixed radio detector requir- ing no adjustment. Caed In place of crystal or vacuum tube detector. Give* excellent quality of aound with- out distortion, battery or tube noises. Detects telegraph signals at several thousand miles. Detects broadcasted music more clearly than vacuum tube detector, and requires no amplifica- tion where the Incoming signal baa sufficient strength to actuate the sen- sitive phones. Ideal for use In receneratlve olr- cults. Handsome, substantia), suitable for assembly In the finest radio equipment. Guaranteed against Imperfection or $3.50 faulty operation. List each THE name "Pruden" back of standard Radio Equipment is a guarantee of mechanical ex- cellence, perfection of workman- ship and scientific correctness of design. Now, more than ever, when the mar- ket is flooded with inferior goods, it pays to buy standard trade marked products. You can pin your faith to "Pruden." Money-back unconditionally if you do not get complete satisfaction. Just one of the leaders of Pruden Re- liable Products shown here that will give you better radio results at no greater cost. Dealers write today for our interesting proposition. FREDERICK H. PRUDEN 993 Bergen Avenue Jersey City, N. J. DONT MISS ANY COPIES OF RADIO WORLD FOR 1923 Be sure to have a complete file of Radio World for the currant year. You can do this by at MM a year (fifty-two number*, tSM six months, S1JS three months). RADIO WORLD, led Broadway. New York City FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Please send me RADIO WORLD for _ . please nmd —closed % sTOBSCKIPTION RATES: «agle Copy I .11 Three Months 1.50 mm Months 3.00 One Year (S3 Issues) LOO Add !» a Year for Foreign i' -n Postage. 1493 Broadway. New York months, for City which tdio World 1 Year (52 Numbers), $6.00 broadcasting to eliminate interference, and the education of the public to the immense opportunities for education and amusement provided by the new art and science. That contributions to churches are on the increase because of radio was the asser- tion made by Major J. Andrew White. Major White gave as an instance the ex- perience of St Thomas's Church on Fifth avenue, from which an entire Sunday ser- vice was recently broadcasted for a thou- sand miles. Before this church broadcasted any of its services, Major White said, the collection plate usually brought in but little returns because the church is a rich one and does not rely for support on the passing of the plate. But after the recent broadcasting contributions flowed in by mail from radio distance of the church. Among the other speakers at the meeting of the Radio Trade Association were Paul Godley, internationally known amateur, and Dr. Lee de Forest, a pioneer in the develop- ment of radio. Mr. Godley asserted that the instrument that would ultimately meet with the favor of radio fans would be one somewhat more complex than the one in average use today. Dr. de Forest spoke on the radio indus- try in the country. 'The fanner is the foundation of civilization," he said, "and agriculture is still the largest single indus- try in the country. People in the cities still look upon country people, however, as not having progressed in the last twenty- five years." He said that they did not realize that slowly a transformation has taken place on the countryside, brought about by greater facilities in communication. "No one art or industry," he added, "wiB do more to complete the evolution of the country than the receiving set" Henry M. Shaw, manufacturer of Newark, New Jersey, elected president of the association, presided. In opening toe meeting Mr. Shaw said that, in his experi- ence of forty yeans as a manufacturer, he had witnessed the beginnings of the elec- trical and automobile businesses. He did not, therefore, worry at the present "grow- ing pains" of the radio industry, for it seemed that every young industry had to grow through certain periods correspond- ing to the measles and the mumps of child- hood. The meeting was an enthusiastic one. Laurence A. Nixon, secretary, was kept busy registering new members. At Your Service! There appeared la RADIO WORLD, dated April t, 15, and 39. the follow***; articles: April 1-A SflO-MUa Wsdjonhsn. Csaployia. a 5- Watt Tobe, by Frank A. Hahnei. "Tel Me, Please, How Win This Set Reecieer" by E. L. Bragden. Short Cats In leejaJear Or enit Design, by O. C Roos. Making a Snort Ware Regenerator, by Fred. Chaa. KhUrt. April IS— First Principles of Brctrteity ss Applied to Radio, by John P. Mike. Your Storage Battery, by K L. Bragdao. What Makes Radio Possible, by Edward Liaweod Ground Connection as Vital aa Antenna, by Fred. diss. Ehlert. April 39— Valuable Pointers on Aerial Coo struction, by Edward Unwood. What Is Meant by Tuaing, by E. L. Bregdon. Radio pun the Variocoupler, by Frederick I. Construct Rumford. Each copy sent on receipt of 15c per copy, or the three copies for 45c; or batter sell send your eubeeirptiou beasaning with say one of these numbers, and we win send tail paper for S3 issue, and you wRI than hare a complete file for ready and asm but refer- ence. RADIO WORLD. MM Broadway. New York. Digitized by Googl

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.1 RADIO WORLD TOBACCO HABIT BANISHED QUICK, SURE, LASTING RESULTS Tammmmm frwateweawr hantahee the habit eosn- pUtaly. aimoat before you kaow it. An absolutely scientific, tboroosfab reliable treatment Ma matter how lone the habit, or Id what form need, »oa will have no crarlnc for tobaeeo af teryoo taka thia pleasant. lnexnonaiTe treatment. This wa poeitiwely guarantee. Your money rotoraad without argument or qoestloo If not satisfied. Writ* for free explanatory booklat and proof of what Tobaeeo Radaamar hat done for man addicted to the tobaeeo habit. Sand peat card or lattar today. O^ltptlTI , SL Laaia, Mn> SURPRISED? Eiaiiii la WE REPAIR RtralHD Amplifiers VACUUM TUBES N a* asm art. esse await w HARVARD RADIO LABORATORIES Tana rttaraai Panel Pert 0.0.0. ■ ■ ■ TI-IirGOODMAN 1 .en.au* . The Nifties* Short Wave Toner on the Marhrt Only UM a W « I h. Send lor oaaenhlet. L. W. GOODMAN DRBXBL HILL, PA. Msrrlrtswe, Pa., writes: IMaalea - ■ -we Tate GOODMAN, sears e miss, -we as issastli allk . an m te wllw mi I ran eae f DtNvta seam le eae seek Ik* tale. AT LAST A Real Loud Speaker at a Reasonable Price The A A P Loud Speaker iclvcs double Or triple the volume of your phono* And at the lime time It clarifies the tone. It la clearer and sweeter than (he most expensive speaker on the market to-day. Its price Is only $4.95 Postage Prepaid Deolert and Jobbcrt tcrite /or proposi- tion Nsts: Tot A a P Loud 8r*«krr owfs It* quality on arc to call three times, sign, and wait for five minutes: then, at the end of thnt time, repeat. He said that he didn't think he was going out very strong so he wanted to make sure that the fellows wouldn't mi in the neigh- borhood would wish he «as some place where he we missed. buck up. fellows! Call 3. then sien ! You'll get tiiere quicker, became well pay more attention to you it you're businesslike! — l-'rank Maier, Now York, N. Y. DONT MISS ANY COPIES OF RADIO WORLD FOR 1923 _j have a complete Ale of Radio World for the current year. You i year (fifty-two numbers, SIM six months, list three months). RADIO WORLD, Ion Broadway, New York City cam do this by subscribes* D-X- RADIO CO. Below Are 70 Reasons For Baying at D-X D-X-Radio Built on ' Foundation* of Lowes* Price* and Tower* of Highest Quality" Bolide* Crip, n Freed- Etermaaa PLUGS round telephone. Torpedo Flat sue IM LS US POTENTIOMETERS Amoco KCA. for "A" Battery. RHEOSTATS Am sco Bredlcyetat Caller- Hammer Co. Fade Type Plunger BakeHte ... China F. E. Moulded .. W. D. II. SOCKETS is 1.01 t.OJ 18 LOB TELEPHONE HEAD-SETS Brandee, Superior BOO- Ohm aft Federal. 2jnonhm tft Tomer. JOHQ-Obm 6.9 Stromherf -Carlson. 2000-Ohm... KV.H Dr. Seibt U 01 "SPAGHETTI* OR TUBING l-ft. leaflet J» TRANSFORMERS SOI 609 4 SO 7.0> Acme Type A-2S MursH R.tr'io Frequency . . TH^"l)rv>n UV-712. RCA. AmplifVinf .. UV-1714. RCA. Amplifying CONDENSERS Morr house Tested 0nn2V.O0n5-.001 40 Morehouse Tested .002 St Morehouee Teeled .006 M SOLDER Solders H. easy to nee, tube 2-os .25 VARIABLE CONDENSERS J PUie 1.25 A B. C 2J Piste }U A B. C 4J Plate .' tot CRYSTAL DETECTORS Ctsst Enclosed, dust proof 1.7} Class Enclosed, dust proof 1J» DIALS Composition, J in. ja Com posit ion, J in t in., lor Rheostat 4 in., with knob. UO Degrees. an at* it* its -5» 7S 13% SAFE-T CRID LEAKS Tubular enclosed in glass Vs. MV 1. t, 1, 4, and S Megohm M Federal, dmtMe Federal, single Firth Type, single Firth Type, double. JACKS 101 e as I M PANELS Hard Ranter, navy specifics lions, none ,"12 17$ J|$ liilS JjJ Remittance Musi er Stamps Net Accept* Peat Paid East An Orders. Merctu D-X-Radio Co. 123 Liberty Street New York G» Digitized by Google

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RADIO WORLD Guaranteed Merchandise « Volt Detector Tubes 91.90 Amplifiers 9* -28 Large Variometer* 91.00 Couplers, 14 tape, pigtail conn 91.2S 48 Volt -V Batteries 91-18 2*ft Volt "B" Batteries TSe Cash With Order STANLEY RADIO SUPPLY CO. 128 East 28 rd street Mew York Regulating Wireless Telegraphy FRESHMAN Variable Grid Leak and Micon Condenser Combined Clarifies Signals, Lowers Filament Current, Increases Battery Life, Eliminates Hissing; Unbroken range — zero to 5 Megohms; all intermediate points. Fixed capacity. .00025 M. F. Only $1.00 At your dealers — otherwse send purchase price and you will be supplied without further charge. Ch^.FRSANCOMPANY,Iiic. 97 Beaskaaaa St, New York City THROUGHOUT the country, with its radio sharps in the remotest settlement, from the small urchin to the oldest inhabi- tant, there is great interest in the Kellogg- White Federal Radio Control Bill, says The Times, New York. The original act of August 13, 1912, is regarded as obsolete. It was the work of legislators who could not perceive even dimly the rapid growth of the giant which they were asked to hold in leading strings. In November Justice Wendell P. Stafford, of the District of Columbia Supreme Court, directed Secretary Hoover, of the Department of Commerce, was 3,900 meters. "We find," said Judge Lamb, "that it is both physically and mechanically impossible to devise or arrange a wave-length at which this plant can operate without interfering with others." Radio regulation moves slowly. The Kellogg-White bill was introduced in the Senate as long ago as June. It may be pleaded for Congress that wireless teleg- raphy is comprehensible only to the ex- perts, and that they are not in accord about its restriction. Secretary Hoover told the Merchant Marine Committee of the House recently that control must be established to issue a license to the Intercity Radio over "the bedlam filling the air from 21,000 r'nmnnn.. «f KTa«. Vftrlf T* 1111 P nnAritiniT T^c\\f\ tRinCm ittinff cf '1 * idllC » T* in ,lu Company of New York. It was operating a high-powered station that put many impor- tant wireless plants out of commission when it was working. Among the com- plainants in the case were the United States Navy, the Coast Guard and Customs Ser- vice, the Post Office Department and the Radio Corporation of America. Judge Stafford had to issue the mandamus asked for because the act of 1912 did not give the Secretary of Commerce discretionary power to refuse a license to the Intercity Radio Company. Judge William G. Lamb, solicitor for the department, said of the statute that it tied the hands of the Federal Government : We are unable to control the situation. Not only will the administration of the Government be hindered, but ships at sea which may have occasion to send an S O S call must wait their turn If the Intercity plant is working; when a disaster occurs. The wave-length of this wireless station RADIO UP TO A STANDARD Far the 'ImjJ WMttMfcMSt R.~ OT 'J2.M _n». T***Jj£ Swjtiii 2(.» BUT DOWN TO A PRICE FOB 39 DAYS prices meat! on RADIO WORLD. All goods new, In original packages. ._ , vamsm &*m&m aMiittaac " 12.(0 I I2l.lt TUgCg f fas* 0. R. 0. J»0J* J 000 swtsra IIM.M .*•>** w 130.00 Testa Dstsstsr get 33.00 O. Fsratt Debater get J5.M Ot FsrsM I -Stan AaaHtsr. ■-- - -• trVT- *- tl.g* 00.00 Tain U. V. to*.... 0. V. 201... Han V. T. I PHONES BalsWta. I'rITle'' Nairn-. Oaktt 2300 ohm.. 10 0 «hm .14.00 . S.M . 3.(0 Navy V. T. W. 0. II. U. V. 201 . Fadtral 300 4000 I .$10.00 . 5.00 . 5.50 . 4.50 . 0.00 . 5.50 . 7.50 . 7.50 I, 7.75 VARIABLE CONDENSERS .0015 Balanrad DeForiit. . $5.00 .0005 Balanead Df Faraat. . 4.50 .011 gSSntSSI OtFnwt... 4.75 J 3 Plat* Moulded Cam.... 1.25 IS Plata Plals 1.00 VARIOCOUPLIRg All Warn, ISO t* 3000 Atwatar-Kaat 14.(0 7.0( 0.00 4.75 t.SO BATTERY OHARSERg Waatlstkaaai 2 Aap 115.00 Wastiaihssa. (Ian*) 0 Ans.2t.00 RHEOgTATg RaaTa Oars. Renter OMaw'tia"' 2.4* .71 .00 M .71 1.20 POTENTIOMETERS ■sols Oars. $1.50 » v.v.v.:::::::::: !:SS An»a» I. it LOUD SPEAKERS ..$11.00 .. 0.00 .. 10.00 .. 17.50 . . 120.00 . 17.50 Kiss DMatl . AatMsta Hsra. Eketrts. VARIOMETERS Atwatar-Kaat IS.50 S.2S 4.00 0.40 TRANSFORM ERS 712 ti.M S.75 Atwatar-Kaat Faosrel RADIO FREOUENOV o. v. mrs™?.. U. V. 1714 ...07.50 ... 1.(0 ... 7M ... 9.79 .. 5.21 .. 4.00 (.00 (.00 2.70 Balswla 4- la. Tall . 4- ls. Patka 5- ls. RaoMB 3-la. Patka DIALS SOOKCTg DeFareat Trials ... W. D. II. 17.00 1.(0 4.7S 2.2S 4.00 11.00 .70 .(( .(0 to.(o .30 .00 1.(0 JACKS ass PLUOO Sua Sri) Flrte, alaala Firth, am Ml (0.70 .00 .30 .00 /Space will not permit us to list all our special values, therefore toe will altuKu quote special prices on any Radio parts or sets you may want. Reliable merchandise first, then price. We will refund, at any time, for Radio material purchased from us which is net up to standard and as represented. No Cheeks. Me O. O. D. Add Parcel P„ost. Reference: Radio World. 977 saTKTLE AVENUE Phono Prospect 2952-8168 BROOKLYN, N. T. COMPLETE YOUR FILES OF RADIO WORLD FOR 1922 of Radio World are becoming scarcer ail the time. We can now tarnish ran with from No. 1 to date at fifteen cents a copy. Any seven numbers for one dollar. RADIO WORLD, 14(2 Broadway, New York CSty radio transmitting stations." It is the regu- lators who will be in bedlam if something practicable is not soon done to harness and guide the monster. By the terms of the bill the Commerce Department is to have charge of all radio communication, licensing operators, assign- ing wave-lengths, passing on apparatus. Day and night the air is full of band music, concert singing, vaudeville dialogues, speeches about everything that interests the American people; sermons, crop and weather reports, prizefighting by rounds, football battles by plays, not to speak of the business of the army and navy and post office. There is discord even between the departments. Secretary Hoover, for in- stance, would have the Navy Department attend strictly to its professional concerns and not stray into fields of entertainment to keep the service cheerful. It has been said that under the provisions of the bill Secre- tary Hoover would have power "to break up the 'Big Four* or any other civilian radio combination." Broadcasting stations are to be limited in number. The attempt cannot be made to control the myriad of receiving stations. The cost would be pro- hibitive even if regulation were possible, fees however, might be imposed, and few could escape them. The Kellogg-White bill will call for a- great deal of discussion before it is put on passage. At the best it will be tentative legislation. The Motion Was Carried AT a meeting; of a certain radio club in a large city in the east, there was a discussion on the relative merits of the superheterodyne as compared with straight regenerative radio-frequency. It " aKe.d S? all.»Sht' the Bi* Boy oV the club talking .„ flowery language about supenmposed" and things of that sort. Suddenly a small voice spoke up and said ttt'Jh^T Ulk *" bn* 1 n°t«ed mat when I was up to your house, that you couldn't get that bunch of junk of yours to even work. Suppose you talk from experience, don't you?" The B. B. turned and, giving the young- ster a mean look, said, "Mr. Secretary I propose that when a speaker has the fin25 a"y T.mtler '."terrupting him be fined a month's dues." When order was finally restored the voungster had the platform. "Say M- L°eT/'„nTVe tla} here»ft", when anyone gets up here and starts talking about Mr. Pet c,r.c»it. that he bring the onSte0fthh:mrPer,mentS a'0n* &nd d- "Second the motion 1" yelled a dozen voices. The motion was carried. halt MarR'e— And he had radio eyes! bue— What do you mean— radio eyes? Margie— Oh just eyes with a broad cast' — Crosley, Radio Weekly. ■ • • a J:^°l report Mys that wir«'«s photo- graphs have proved successful, which is Tt** Can^Said °„f ™ST °* Them you oy K. Moulton. in

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RADIO WORLD 27 JIADIO ^.STORES iyLcoRP The Supreme Set Uses Radio Stores Variable Condenser alio acknowledged supreme in its class, DeForest, after competitive tests, chose the Radio Stores Variable condenser, in accordance with their policy to use nothing but the Tery best. It has the following features: Concealed Counterweight Under Dial. C„„„U„„ Bras. Studs Through Aluminum Plates, and jpeaKef Die Cast. Shaft Held In True Center Through Brass Bushings. No Insulating Material Tapped— Metal Inserts ^ The Set Without An Equal DeForest Generally acknowledged the supreme achievement in radio receiv- . ing sets. It combines three steps of radio and two of audio on only three tubes, and can be used either with inside loop aerial or out- side antenna; has single knob control ; is super - sensitive, with unusual range. Operating in New York it has received Louisville, Chicago, Atlanta, Pittsburgh, Boston, Detroit and Havana. The net is only lOxlltoti Inches. Complete with loop. ".V Battery (Evereudy !K) Amp. Hr. storage). 2 *'B" Batteries (Kveready !K) volts). Pictogruph Headset. Dictograph Loud- Speaker, 2 Radio Stores Torpedo plugs. All Complete $175.00 Loud Throughout, ion Wbrkn Precision sign. 23 Plate 28 to 1 « Plate 46 to 1 ship-Best LIST mfd.. Capacity .001 mfd.. Capacity *ati.°$4.75 Complete with Knob, Dial and Counterweight. Packed in Individual Carton. The Radio Stores Torpedo Plug, $1.25 •s * truly worthy companion to the Dictograph and DeForest product.. It makes a parte* connection with both jack and cord In It is unbreakable and is especially desirable tar the fallowing reasons: All Conductive Parts of Heavy Machined Brass. Insulated Throughout. Screw Binding Post Terminals. Separate Knehor far Tall of Card. Designed to Insure Rigidity. Durability. Itrtngth and Lightness. Packed In Individual Carton. The Dictograph Loud Speaker combined with the DeForest Reflex provides the utmost in Radio reception. The Dictograph Products Company ha» been known for many year* at one of the world's foremost designers and constructors of Acoustic appliances. Thu* the Dictograph Loud Speaker, the newest addition to their famous line. Is the product of their many years of experience. Dull gold Black and 5 foot silk cord. Loud and clear in .. or howling. $20 UNBREAKABLE! Patent Pending Message to Dealers— Just drop us n card to get your name an our mailing list, to receive advance information on money-making opportunities and new invan. are manufacturers and also distributers for DeForest and Dictograph products. Large stocks for immediate deliveries. With the DX Nite Owls (Continued from page 19) Honolulu; KDYR, Pasadena; WHAS, Louisville; WLAP, Louisville; WDAK, Frankfort; WEAN, Providence; WGY, Schenectady; WSB, Atlanta; WBAP, Fort Worth; PWX, Havana; WOC, Davenport; KSD, St. Louis; KFBV, Colorado Springs; WCAC, Phoenix; CFCA, KDYQ, and others too numerous to mention. I use one step of radio-frequency and detector only. * * * Set Cost Just $101 From George Franz, 2*8 Sooth Clarkson St., Den- ver, Colorado. 1HAVE written you before about my set, but recently I added two steps of radio-frequency. I am sending you the stations which I have received, most of them with my old set ; but they now come in much stronger and more clearly. I still have no connections soldered; I did not have in my other set. My set, com- plete with storage battery, B batteries, phones, and the five tubes, cost me $101. This, I think, is very reasonable consider- ing what the sets sell for at a retail store. I am using Radiotron Tubes. Following is a list of the stations I have received with this set, everyone coming in very loud and clear: WOC, WBAP, WHB, KZN, KWH, WBL, KHJ, KFI, KFBB, KFAA, WOI, WDAF, CFAC, CJSC, CJCG, CJCD, 6XB, CSCN, KSD, KDKA. Testing out the set the other evening, I found that I could unhook the aerial and ground and still hear local stations very clearly. Testing it out further, I dis- connected the tuner from the rest and using no ground or aerial I still heard local stations. Attaching the aerial to the input on the radio-frequency and using no tuner, I heard the local stations very loud and clear. * * » A Vario-Coupler Record From Lambert Jones, P. O. Bast 164, Benton, 111, 1AM sending my receiving record of the last two months. My receiver is _ a vario-coupler with detector only. The aerial is 30 feet high and 200 feet long. I haven't as yet seen any vario-coupler records. The following stations come in very clear and strong: KHJ, Los Angeles; PWX, Havana; CJCG, Winnipeg, Canada; 5-ZA, Roswell, New Mexico; WMAS, Southamp- ton, Massachusetts; WBZ, Springfield, Massachusetts; DN4, KLZ and KFAF, Denver; WFAA, Dallas; WPA, Fort Worth; WOAI, San Antonio; WEAY, Houston; WHAM, Rochester; WEAF, New York City; WGR, Buffalo; WGY, Schenectady; WAAC, New Orleans; KSDS, 75 miles from Denver. WHB, Kansas City, Missouri, comes in so loud that often music may be heard all over the room. * St * Can Eliminate Static From C C Frank, Oriental Hotel, Galveston, Texas. I READ Radio World as fast as you get it down here. My set is a single-tube hook-up that will bring in WWJ, KSD, WOC, WSB, WGM, WBAP, and all the central-rime stations. I am no radio engi- neer, just a radio bug. There are ten sets like mine in Galveston, all getting the best of results, and sometimes when the weather is cold. I can get WEAY over fifty miles away without any aerial or ground. I get the Sweeney School (Kansas City, Mis- souri) on a loop. When static is bad, I change and put the ground wire on the an- tennea side of the set and the antennea on the ground side. This is not a joke, as I believe th ground waves bring them in louder and decrease the static. I don't use any amplification on this set as it kills the sig- nals. I can produce witnesses as tp how this set works. My distance record is 2,000 miles air-line, but there is one State I cannot get — California. I am just three squares from the Gulf of Mexico, and have a one-wire aerial 100 feet long with a ground for a water pipe. The apparatus I use is one 23-plate con- denser, one 3-plate vernier, one vario-coupler. G.-E. detector No. 200, pencil-mark grid leak, Fixed Phone condenser and a Ford battery for my A battery. » » * Good One-Tube Record From Melbourne Renken, Box 113, Cole Camp, Missouri I HAVE seen letters in Radio World from many radio fans with their long-distance receiving records. I am using only one tube and a home-made regenerative set and have received over a hundred stations. I have received as high as thirty in one night. Some of my "distance" is PWX, Havana; KWH and KHJ, Los Angeles; CRCR, Re- gina, Canada; CFCD, Toronto, Canada; CJCG, Winnipeg, Canada. MJZ, WGY, WOR, WFFD, KDKA, WGR, eastern sta- tions; WWJ, WWI, WSB, WDAJ, At- lanta; WAAC, New Orleans; KZN, Salt Lake City; WFAA and WDAO, Dallas; WCM, Austin; WBAP and WPA Fort Worth; WLG, KFAF, KDZQ, Denver; WDAP. WGAL, WMAQ, KYN, Chicago; WOC, WRL, WJAP, WLAG and WLAJ. I think, that this is pretty good on one tube — don't you ? When the girls get to sending their kisses

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28 RADIO WORLD PATENT Yoar Radio Iiku. Call er Writ* FREE ADVICE r-c^520 FIFTH AVE SPECIAL OFFER For a limited time only. Parsuron RA-10. .$68 Grebe CR-5 «7t Paragon DA-*... 08 Grebe ROBK W Prices F.O.B. Red Bilk, N. J. A. V. GREGORY « Broad Street Red Bank, N. t. AMERICAN ELECTRO PHONE CO., Inc. 813 FIFTH AVENUE, NEW YORK CITY DISTRIBUTORS Full Line of Nationally Known Radio Seta And Acceaeorlee Discounts to jobbers and dealers. GITHENS TRUTONE RADIO HORN— LOUD SPEAKER - to aell on ten day trial Honey back Guarantee Load Trutone has been pronounced the beet an the mertet b; experts. It hu • eleer. true tone. Story radio fen ehould trr Trutone end compere It with ethers. If YOU don't find Trutone the beet, jour owner will be refunded. It le eold on e ten-day trlel money-back guarantee. If not carried br your dealer write ua Distributori and Dealers, write 1 AUTO PARTS MFG. CO. IRIS Tromhly Ave. Detroit. Mlrta. SEND SPECIAL OFFER $3.60 Cash or Money Order Oaty. aa*J we wOa TEC that they are a* good la worhrasnohhe SYKES MFG. COMP/UJY U SPRINGFIELD AVENUE NEWARK. N. J. Radio World, 52 issues, $6.00. Subscribe direct or through your news dealer. $6.00 a year, $3.00 sis months, $150 three months. Radio World, 1493 Broadway, N. Y. C Radio Slang Worries Pro- fessor PAGE the orthodox grammarian! There is danger that even the modern slang of conversation will be revolutionized and given added stimulus toward lower depths of abbreviated phraseology, says "The Globe," New York, if radio messages become common means of communication, accord- ing to students and professors of Ohio State University. Professor Charles A. Wright, of the department of electrical engineering at the university, raises the question, if amateur radio operators increase in numbers, will their abbreviations slip into common usage and thus become a part of the Ameri- can vocabulary? As an example of what might be thrown at a person during informal conversation with one of these fellows cards received at Robinson Laboratory broadcasting station on the campus are submitted as evidence. One from San Juan, Porto Rico, reads: "U wr wkg 2 EL. Am I rite? Would like to hr fm u. Congratulations OM." By way of interpretation the following may be noted : OM means "old man" ; wkg, "work- ing"; wr, "were"; U, "you"; hr, "hear": rite, "right." Another card from an operator in Fort Worth, Texas, says: "Ur C. W. steady. Called u but N. D. Hv u ever hrd me?" QSA is the international abbreviation for 'loud." ND means "nothing doing." Otherwise the message is very convincing to the average reader, is it not? A Radio Serenade SWEETHEART, alas, I cannot sing. My voice to song is not adjusted. I sound — comparison to bring — Like buzz-saw biting nail that's rusted, If 'tis like anything. But thanks be to the radio (To Friday's program I refer you). A proxy serenade I'll throw Upon the evening air to stir you, While I with passion glow. Hook up your wave-lengths, pet, to hear From KPX at eight precisely. The barytone who'll thrill your ear Will summarize my feelings nicely. The Bedouin Love Song, dear. And then, you'll note, I give a choice (Beneath your ledge in spirit straying), There's GKV with Heart, Rejoice, Or APJ .with Let's Be Maying. My views, if not my voice. One -word of caution let me say. Do not, I pray thee, feel offended If Weather Forecast for Today Should interrupt my song extended ; It sometimes works that way. And there's another thing, my dear; It can't be helped, and more s the pity — The static in the atmosphere With shrieks may mar the sweetest ditty. Believe not all you hear. Drink to Me Only with Thine Eyes (Quartet; YZ) will end my rapture; Four proxy swains as one will rise And sing for me, thy love to capture. Sweetheart, some enterprise! — Arthur H. Folweix, in The Ladies' Home Journal. His Definition of Radio AN engineer gives as a definition of •*•*• r^tdio "a system of communication whereby intelligence is transmitted with the speed of light in all directions, for any desired distance, without the aid of any artificial medium, by the propagation and detection of electrical disturbances in space." Build Your Own Set THE RADIO CONSTRUCTOR" A book showing twelve prize book. I lea up* and full deUili of Just how to 1 »J\ build your own act saving half its coat. S NEWMAN I 00.. 74 DEY ST., SEW TOW RADIO MAILING LISTS 12,400 Radio Dealers, eeverlns U. 8. by States per at. 17.00 1.614 Radio stirs, sovsrlsf U. 8. fey Statu oar list lt.00 1,701 Reels Supply Jabbers, oeve.ins. U. 0. by States par list. 10.00 260 Radio Stations ear Nat. 4.00 2S7 Mfra. who make aad asseable sea- •lets Radio Sets par list, 4.00 20.000 Radio. Ae.at.urt aad Msaafars s? Radio Statlees ear at 7.00 A«fc for erl.c I t-t» for Ciaade. Ceelead. ether lists. TRADE CIRCULAR ADDRESSING CO. 160 W. ADAMS SIRLET CHICAGO. ILL. Quality, Design * Workmanship + iJOt«rtol s BMUAB1L1TT Simple to Use Juat ping as. 'at my U0 «. A. C 1 lamp socket at. ' tach cHpc to bat- i cry— turn on ear. rent and TOO have yoar ing | A compact portable Recharging unit that will fully charge a 100 AH battery overnight for Sc. to 10c At your dealers or write King Electric Mfg. Co., Inc. 1001 Fillmore Avenue Buffalo, N. Y. RADIPHONO ADAPTER $2.00 Here Is an ctrieleet sss- omleal way is aas saw let role. Bdtaan. Bronewke, ate., as a wonderful brad maker. This adapter la uaouHed of sasulsd caeapsslUao. It ellatlnetee aaetalUr aad du- nned sounds. Guaranteed te be satlatastary or aeons, refunded. If you dealer cannot supply yen send as 10.00 and era will avail saa by panel post prepaid. Industrial Sale* Enantaeerlaej Co. 071 Bread Street. Newark, N. J. Phone, Market 9023 Look Spider Web Inductance and Discs that give the wonderful re- sults as described in Radio Age. Inductance wound complete. .$2.M Disc Only M Diagram for conaectiena free with ardor. We are manufacturers of Stor- age Batteries for Radio A aad B circuit WRITE FOR PRICES International Battery Co. 112 Louis Street, N. W. Grand Subscribe for RADIO WORLD, year, $3.00 six months, $1-50 three $6DOo

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RADIO WORLD 29 DO YOU WANT TO BUT. SELL OR EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT h A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department is intended for everybody who wants quick action on short announcements covering the boring, setting, exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that it pays to read these columns every week. Advertisers will get a ten-day service here— that is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy reaches us. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is 5c. per word (minimum of 10 words, including address), 10% discount for 4 consecutive insertions, 15% for 13 consecutive insertions (3 months). Changes will be mads in standing classified ads. if copy is received at this office ten days before publication. RADIO WORLD CO, 1493 Broadway, N. Y. C (Phone, Bryant 4796). SACRIFICE— Tuning- coil act with variable con- denser, antenna, phones, etc Sell $12.00. Carl Masson, 76 Boylston S., Jamaica Plain, Mass. AMATEURS I Send for list new radio parts, 40% to 75% off list. Cunningham, 282 East ISSth St., New York City. FIRST MONEY ORDERS TAKE 'EMI Tusca Receiver and two step amplifier, type 22S, in perfect condition, for only $58.75. Also one Rein- arts tuner, <*etector and two step amplifier with automatic filament jacks, formica panel, and mounted in beautiful cabinet. A fine amateur DX and radiophone receiver, $54.50. Rubert Lewis, 625 S. Church St., Princeton, I1L PATENTS — Electrical cases a specialty. Pre- war charges. B. P. Fishburne. Registered Pat- ent Lawyer, 386 McGill Bldg., Washington, D. C. EXCHANGE LETTERS with new friends, many wealthy. Information for stamp. SMITH, Box J 125 M, Portland, Oregon. Broadcast Bill's Radiolays By William E. Douglass HiZEKIAH SINGLETREE'S a "Wire- less Bug" fer fair; he sez that he kin pick up stuff frum almost everywhere. No matter where I meet him, he will hand me out a line about how good his set is — sez it's just as good as mine. Now he made his with balin' wire an' cans frum "Father's Oats"; of course they ain't no more alike than pigs an' billy goats. But that don't stop him "Now. Folks, ril Bat Yon Couldn't Gums What It Wua All About." talk in' cause he'll argue all day long, be- ginnin* after breakfast 'long 'bout noon he's goin' strong. To please him I went over to his house the other night (I'd rather stayed at home where I could hear the concert right). But nothin' else would do because he wanted me to hear how he could bring We Want Your Name M a sesM ears. Wi mM Nee ts set tks wm St evarv SADIO WORLD raeew. sa *s sassvt m —4 nt a ssnlal assesses Is ear rnsiu. It «M hwwsst «•*. Be sars Is seae as war aasw fa a ssstel ear* ana aSerass It SIFT DEPT., RADIO WSSLO. |4M Breeave,. N. Y. OLD MONEY WANTED— 82.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 centa for New Illustrated Coin Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave. 83, Le Roy, N. Y. WE NEED RADIO WORLD, dated April a and August S. Il you have copies you don't re- quire, mail to this office and current issues will be sent you for them. RADIO WORLD. 1493 Broadway, New York. EXCHANGE LETTERS with friends everywhere Pleasant pastime. Information for stamp. South, Box 3125. H. Portland, Ore. BROADCASTING MAP of the United States appeared in RADIO WORLD No. 8. Sent on receipt of 15c, coin or stamps: or start your subscription from that number (S&.0S for 52 issues). RADIO WORLD. 14S3 Broadway. Now York them stations in, no matter, far er near. So puttin' on the earmuffs I tried hard to tune 'em in. an' once I heard a feller playin' on the violin. I told Hez what I'd heard but he sed, "That's my daughter Claire a prac- ticin' her lesson, that ain't music frum the air." I tried again but all I got wuz squeals an' that there static; I sez ,"If this here set wuz mine, I'd store it in the attic." When I took off the headset I could see that Hez wuz sore or sorter puzzled like at least, I couldn't see what for, 'cause I wuz only kiddin' him, but I found out today, when I wuz down to get the mail, why he had looked that. way. Now folks I'll bet you couldn't guess what it wuz all about, but Hez an' me are friends again, we've straight- ened it all out. It seems that it wuz this way, while I set there by the set with rub- ber earmuffs clamped on tight a tryin' to get some far off distant station, north er south er on the coast, most any place so Hez could say that he'd made good his boast, he'd asked me if I'd like to have some of the "cup that cheers," "some real old stuff" aged in the wood, that he had kept fer years. With earmuffs on I didn't hear a single word he'd said an' fer some unknown rea- son I must of shook my head. But it's like Doctor Coue sez (correct right to the letter) CASH FOR OLD COLD, Platinum, Silver, Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash sent, seturn mail. Goods returned in ten days if you're not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. NEWS AND GOSSIP OF THE STAGE— Send 10c for specimen copy oT NEW YORK STAR, the great illustrated theatrical weekly. K.0S rear, $2.00 six months, $1.00 three months. Maw York Star Co., 1493 Broadway, N. Y. EXCHANGE JOLLY, INTERESTING LET- TERS through our club. Stamp appreciated. Betty Lee, Inc. 4254 Broadway, New York City. BACK NO. RADIO WORLD WANTED— The publisher wants copies of Radio World of April 22. Mail us copies and current issues will be sent Km in return. RADIO WORLD, 1491 Broadway, ew York City. "For day by day in every way its getting better and better." Copyright, 1922, Westinghouse Electric tc Manu- facturing Company. Crystal Detector Not Recent Invention \/|ANY authorities now state that old ivi patents, magazines, and other scientific literature show that the crystal devices claimed to have been "patented" were described in these magazines and patents many years before the present holders' "patents" were applied for. There is a great volume of this literature, it is said, in French, German and Dutch languages, as well as in English, clearly explaining the crystal detector, no one ever having bothered to file patent applications on them until comparatviely recent times. No Free List To many nasi oats inquirer a: RADIO WORLD has ate free list. Oat* copy is stmt as a vouchor to each advertiser ar advertising agent represented 1st inn— I issues. All other copies are paid fer ee subscription or through the news tresis Attention! Fans and Amateurs! Have you built your own receiver? Are yon experimenting with say par- ticular book-up? Are yon improving your set? Are yon doing any interesting construc- tive work in radio? Way not store this fenowtafo* teat* yew faooaawds of brother font who read RADIO WORLD every tosefef We want pictures of receiving sets with descriptions of how vou overcame boom difficulty, or of any additional part or euu't that yon have added to obtain better results. These are the things that, prob- ably, the other fellow is looking for. Send in your information; pictures or what- ever you have done to improve the art. them. We intend to print in tins week, pictured information and descrip- tion of value to radio amateurs. If yon bar* found a newer or better way of doing anything, don't keep the secret but tell it to your thousands of brother fans. Send in a photograph of your set with or without accompanying diagrams and measurement. State whether yon figure in the picture yourself, or not, and with- out any expense whatsoever to yon we win make an engraving and publish it. Be sure to write your name and address plainly on photograph. Send in your picture st once, or if you have not made a set or done anything else in meking radio material. teO the boy neat door all about this offer. AcMroas Technical Editor RADIO WORLD. 1493 Broadway. New Y. Diniti7firi hv *kclty'N- Y.

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I RADIO WORLD Complete Your Radio Library for 1922 Useful Technical Articles Published in Former Issues of Radio World APRIL L A 500-MUe Radios* mm Hm ploying a B-Watt Tube^^ Freak A. 'Hahnel. Me, PlMae, How Will ThU Bat Re- ~ l. Brandon. in Reoslvsr-Clrouit Design, by O. Maktog a Short-War* Regenerator, by Chaa. Bblert APRIL 8. Do Ton Kaow Tour Receiving Equipment, by Jamas D. Gordon. Wb7 a Crystal la Called a Rectifier, by W al- tar ™ - ■ * la Radlotelephony Dependable T by O. C. Rooa. Mounting CrjrataJa In Tour Detector, by K. L. Bragdon. Storage Batteries for Radio, by Prod. Chaa. Bblert APRIL IS. first Principles of Electricity aa Applied to Radio, by Joan P. Miles. Toar Storage Battery, by B. L Bragdon. What Makes Radio Possible, by Edward Lla- wood. Ground Connection as V1U1 as Antenna, by Pred. Chaa. Bblert. APRIL s». Valuable Pointers on Aerial Construction, by Edward Llnwood. What U Meant by Tuning, by E L Bragdon. Radio-Frequency Ampllflcatlon and Regene- ration, by Prank Armstrong. Honey-Comb Colls and Condensers, by Ed- ward Llnwood. Charging the Storage Battery, by R L Bragdon. Row to Construct the Varlooonplsr, by Fred- erick J. Romford. MAT 8. The Advantages of Radio Frequency, by Harold a Potter. How to Construct, Protect and Operate a . t George w. May. The Beginner's Catechism, by Edward Lln- storage Battery, by (rood. Tuning and What Is Meant by It, by Prod. Chas. Ehlert. New Prequency Amplifier Brings Palataat Wares In Strong, by O. W. May. MAT 18. My Practical V. T. Detector and Two Stage Amplifier, by Frederick J. Romford. The Principles of Radiotelegraph/, by Wal- ter J. Howell. The Resson for the Loop Aerial, by George W. May. Toning and What Is Meant By It, by B. L. Bragdon. The Beginner's Catechism, by Edward Lln- wood. MAT 20. The Design of an Amateur Reoelrlng Set, by C. White. The B Battery and the Plate Current, by Oeorge W. May. Radio Terms at a Qlance. by Pred. Chaa. Ehlert. The Beginner's Catechism, by Edward Lln- wood. Fire Undowrlters' Rules, by Fred. Chaa. Bblert. MAT 27. The Beginner's Catechism, by Edward Lla- How to Make Tour Own Condenser, by Oeorge W. May. Tuning aa Applied to Telegraphy, by Walter J. Howell. Why the Condenser Doesn't Condense, by E. L Bragdon. Making Signals Louder with Two-Stag* Am- plifier, by Oeorge W. May. _ JUNE 8. The Coat of a Single-Circuit Receirer, by Howell W. Miner. The Beginner's Catechism, by Edward Lin- wood. How to Compute and Build a Fixed Conden- ser, by B. L. Bragdon. ftWMta.'0' *" Am"**"r'" R#oelTln* Sat, by Simple Method of Recharging a Storage Bat- tery, by John Grayson. JUNE 10. Radio Receirer for Short Wsrss. by Oeorge W. May. How to Filter Atmospheric Conditions, by C. White. The Messenger Boys of Broadcasting, by B. U Bragdon. Are Ton a Member of the N. O. D. C. T by B. L Bragdon. The Beginner's Catechism, by Edward Lin- How to Construct One- and Two-Slide Tuning Coil*, by George W. May. JUNE IT. The Vacuum Bulb's Hurt In Life, by C. White. How to Select the Right Bet. by B. L Brag- The Beginner's Catechism, by Edward Lin- Test of Inductance Coils, by Fred. Chaa. Ehlert. Short Wares from a Simple Reoslrer, by Stanley Bryant. JUNE 34. How to Make Tour Radio Cabinet*, by W. 8. Standlford. How the Crystal Detector Is Ossd to the Beat Adrantage, by C. J. Williams. How to Construct a Long-War* Regenera- tlre Receirer, by Oeorge W. May. Tested Inrentlon of Major Armstrong Ampli- fies Set 100,000 Times, by John Kent. Repairing Cracks In Hard-Rubber Storage Battery Jars, by W. S. Standi ford. The Beginner's Catechism, by Edward Lln- wood. JULY 1. Novel Unit-Detector and Amplifier, by Fred- erick J. Rumford. Why Tou Must Use a Condenser, by C. J. Williams. How Ware Lengths Trsrel, by Fred. Chas. Ehlert Radio World's Revised Dictionary, by Fred. Chaa. Ehlert. The Beginner's Catechism, by Edward Lln- wood. Use of the Vacuum Tube Detector, by Oeorge W. May. JTJLT 8. Radio's Plaos in the Phenomena of Nature, by B. L. Bragdon. The Function of the Loose Coupler, by Charles H. Plath. Armstrong's Superregeneratlre Amplifier Fully Explained; by John Kent. Operating a Transatlantic Station, by Fred. Chaa. Ehlert. The Beginner's Catechism, by Edward Lln- wood. Reducing Strays and Static, by Fred. Chas. Ehlert. JTJLT IS. Assembling a Detector and Two-Stage Ampli- fier, by H. 8. Stanford. Combined Radio and Audio Frequency Ampli- fication, by C. White. The Beginner's Catechism, by Edward Lln- wood. Locating Tour Aerial, by Harold Day. Pacta for Beginners, by Pred. Chaa Ehlert JTJLT 22. When Tour "Moriss" Come by Radio, by Stan- ley Bryant. Underlying Principles of the Vacuum Tube, by George W. May. Practical V-T Detector Panel, by Frederick J. Rumford. Revised Radio Dictionary, by Fred Okas. Ehlert The Beginner's Catechism, by Edward Llnwood. Importance of Aerials to Radiation, by a White. JTJLT 29. The Vacuum Tube as a Transmitter, by Charles H. Plath. My 20-Kllowatt Tube and it* Uses, by bring Lnngmulr. Importance of the Capacity Switch, by B. L Bragdon. The Truth about Lamp-Socket Aerials, by Harold R. Hart AUGUST S. How to Construct and Operate the . Superregeneratlre Circuit, by John Kant Using Radio Frequency /to Extend Rang*, by Oeorge W. Msy. Things Every Radio Fan Most Know, by B. B. Hawley. Revised Radio Dictionary, by Fred Charles Ehlert AUGUST 13. The Work of the Audio-frequency Transformer, by Oeorge W. May. Practical Measurement* of Capacity and In- ductance, by W. A. Dickson. Experimenting with Armstrong Circuit Pro- duces Unusual Hook-up, by Dr. O. 8. Kelly. How to Secure Perfect Regeneration, by Fred. Chas. Ehlert AUGUST 19 How to Build a Portable Field Busier, by Do Witt H. Thompson. Using Two Tubes for Recelrlng, by C. White. The Storage Battery at an Important Factor In Radio Reception, by Donald Van Wyck. The Use of Capacity In a Circuit, by Oeorge W. May. The Beginner's Catechism, by Edward Ltawood. _ AUGUST 26 How to Build a Splder-Web Receirer. by Frederick J. Rumford. My Detector and One-Step Amplifier, by Fred. Chaa. Bblert The Beginner's Catechism, by Edward Lln- wood. Hlnta for Fans, by C. F. Rye. SEPTEMBER 2 _Oenerattng C-W for Transmission, by C. White. ^^Vonjcrs of Radio-Frequency Amplification, by H. S. Potter. How to Connect the Electric-Light Socket Aerial, by John Kent Practical Circuits for Regenerating Land Sig- nals, byxO. S. Kelly. SEPTEMBER t Radio Ideaa for the Amateur to Tost Oat by Carl Masson. How to Make a Practical Wave-Motor, by Frederick J. Rumford. • How to make a Honey-Comb Coil with a Two- Stage Amplifier, by Pred. Chaa. Bnlert Perfect Short-Ware Radlo-Freqaeaey Amaa- fleatlon, by George W. May. SEPTEMBER 16. How to Make a Two-Tube Buperregeaoraler. by Frederick J. Rumford. Methods of Amplifying Radio Signals, by B Bradbury. Voice Distortion la Vacuum-Tube Becetrore. by W. A. Dickson. Charging a Battery — from a Preni Point of View, by Marius Thourala. Working Diagrams for Beginners. „ „ SEPTEMBER 2371022 p New ^V ^Hook-up Worth Testing Out, by ^New Method for Lighting Filaments, by C. _ Why the Radio Compass Is the Fighting Element of Science, by Ortherni Gordon. Complete Table of Symbols Used In Radle Reception, by Fred. Chas. Ehlert. The Rndlo Primer, by Edward Llnwood. Complete Method for Building an Electron Tube Detector Unit, by Experts of the United States Bureau of Standards. SEPTEMBER SO, 1023 Increasing the Ware Lengths of a Receiv- ing Set, by Oeorge W. May. The Importance of the Variometer to a Re- ceiving Set. by Donald Van Wyck. Successful Stunts of an Amateur Radio 1st. by C. F. Rye. Employing Jacks with a Two-Stage Ampli- fying Receirer, by Fred. Chaa. Ehlert. v OCTOBER 7. Superheterodyne Receiver as Applied to the Armstrong Superregenerstire Circuit, by Charles R. Leutz. Constructing s Radio- Frequency Regenerator, by C. White. Why the Open Antenna Is Best for the Radie Listener, by C D. Wagoner. Broadcasting Stations of United States aad Canada. 1 The Radio Primer for the Beginner, by Lyaa Brooks. OCTOBER 14. Neat Home-Made Tub* Socket, by Gordon a. Arthur. Vessels Now Guided Through Fog by New S*?£m °J. Radiotelegraphy, by Otherus Gordon. Whst Makes the Receirer Work, by Donald Van Dyck. Using the Vsriocoupler in s Short-Ware Re- ceiver, by George W. May. Regenerative V-T Receiver for Short Wares, by Fred. Chaa. Ehlert. . OCTOBER 2L Important Improvements in Radio Receivers, by C7 White. ^ Be Sure ol Your Ground Connection, by Fred. Chas. Ehlert. How Radio Was Installed in Oar Hons*, by Hsttie Briggs Hartman. One- Tube Regenerator Hook-up for Load Bigs, by Harold Day. Kent17 Rldi° Set H" * Re,uble ■*»«*• by Joan The Theory of Radio Communication, by Horace Beers. , , OCTOBER 28. ,, Jlr!Ple Super-regenerstire Receirer. by Har- old S. Potter. 'Vacuum Type of Arrester Safe, by Fred. Chaa. Ehlert. How to Make Your Aerial Function, by Horace Beers. How to Avoid Interference When a JOB Mater snd s 400 Meter Station Are Operating Shawl- tancously, by C. W. Horn. „ . , NOVEMBER 4 Receiver for Amplifying Weak Signals, by Hor- ace Beers. How to Learn the Code, by Orthems ,rDe«?,0^Mnd How Th** Work, by Van Wyck. One of the Most Delicate Parte of a R by George W. May. c.^"™!, er fo/ Amateur Operators, by United States Bureau of Standards Experts. _ NOVEMBER 11 How to Build a 100-Meter Concert Receives* Set by Frederick I. Rumford. ^endw^cVEXPerimenti°« Witk A*ri»to- * Single-Tube Superre gen era tire Receiver, by C. White. Utilizing Ford Spark-Coils for Audio- Freoaeney Transformers, by Ortherus Gordon. ~ Wo7. " U Necessary to Tune In, by Arthur u. Shirt. Any single copy of Radio World, be- ginning with No. 1, mailed on receipt of if "nt» Pf»*P»id. Any seven issues tor 5I.Q0. All 41 issues to date for $5.25. Or send $6.00 for 1 yea, (52 numbers) aad have your subscription start from No. 1 Radio World. 1493 Broadway, New York. Digitized by Google

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RADIO WORLD Big Impression Gained at the American Radio Exposition AN observer at the recent American Radio Exposition, the first of any national importance, must have been greatly impressed by the absence of great changes in radio receiving sets. As has been predicted by leaders in the industry, the sets for 1923 will be only slightly changed from those of the past year. Refinements rather than startling innovations will be the order of the day. If there is any one item that shows the advance of radio it is the increasing use of radio-frequency units. This is but a natural outcome of the desire on the part of owners for sets that will cover distance. Of freak sets but few were to be seen. One exhibitor showed a complete set in the pedestal and globe of a floor lamp, but otherwise than this the manufactur- ers have settled down to the more common- place outfits. Few crystal sets were observed. Those that were comprised permanent detec- tors which do not depend on the fussy manipulation of a hairlike wire. Loud-speakers have been improved, but no radical changes in design could be observed. Rumors are circulated of laboratory tests on remarkable speakers, but evidently the developmental work had not progressed to a point where the mechanism could be exhibited. To Rebroadcast American Radio in \Canada AN experiment which may change the broadcasting plans of the country will soon be tried in the station of a large Mon- treal daily. To technical men, the new plan is known as retransmission, and although it has been tried many times in an experi- mental way, this will be the first time that it has been given a practical test in rendering public service. The' radio broadcasting station of a Mon- treal daily paper will be used to rebroadcast entertainment of the New York stations. The New York programmes will be picked up in Montreal with a sensitive receiver and highly amplified. The output of the receiver will men be fed into the broadcasting equip- ment and the very entertainment that is be- ing sent forth from the New York stations will be enjoyed by the "listeners-in" in Mon- treal at practically the same instant. High hopes are held out for the success of the experiment since it will mean a great deal to broadcasting if practical. Working on this principle it will be possible to oper- ate two or three big central broadcasting stations with the smaller stations in the out- lying districts used only for retransmission. In this way, two or three stations could blanket the entire United States and the money that is new being spent on the enter- tainment for several hundred broadcasting stations could be concentrated on a few. Attention, Newsdealers You should keep a goon' supply of back asnbere of RADIO WORLD on band all the usae. It ha* been the experience of many dealers *et a purchaser of RADIO WORLD for the first uae will almost immediately want the back ssunbera, some of which are already out of print sad some of which are difficult to get. THE PUBLISHER WILL FURNISH BACK NUMBERS TO DEALERS DIRECT OR THROUGH THE AMERICAN NEWS CO. AND ITS BRANCHES. Dialers should hold their unsold copies for a reasonable length of time. RADIO WORLD of October 28 contained a full page of contents of sack numbers to that date. 15 cents per copy; say seven numbers for fl.OO. RADIO WORLD, m Broadway, New York. Fifty-two itracs for f&M. Sab. De- nrtment, Radio World, 1493 Broadway, V Y. C LOWEST OF ALL A Stock of Standard Merchandise at Price* Never Offered Before Our Ust Prise D* Forest Stasia Tube Bet (Adapt- able to 144 V T»lbe) 186.00 $18.88 De Forest 1 Step Amplifier '38.00 18.90 De Forest Brerrsun with Phones.. S5.00 12.90 Dt Forest Deteetor 1 Step SP 3.. 42.00 28.00 De Forest OT 8 Midget Badlo- pbone Transmitter sod Bacerfer.. X00.00 SO. 00 (5 or more sots 20% disoount) De Forest Crystal Deteetor 8.79 1.00 De Forest Bakellte Tube Sockets.. 1.00 .00 Dictograph Headsets 8.00 4.(8 Braob Lightning Arresters (In- door) 2.90 .88 Braeh Lightning Arresters (Out- door) s.00 1.29 H. B. SHONTZ CO, INC. 181-187 West Uth Street New York City "A Real Throe Tuba DX Circuit" Em- Paying Three Tuba* but Functioning as a Three Radio and Two Audio Frequency Sat. Complete Wiring Diagram $1,801, 28.80 HaMttos Stores. "B" Batteries, 22U vslt varlsMs. No isnersl cost— atom Iryieo sad erdlaery "B" battery alsadvastaoes. Guaraatse* $2.79 •see •4.98 i3-Pl'a«V $98.00 •82.80 43 -Plats Faderai Federal Variable' 'Variable ...$2.29 Bekell lalrta 80s Baksllts ••f-Ai *l.29 Aasiner.. . $80.88 Aasllftar sad Deteetor, CASH WITH OROta *UM ROBIN ENGINERING COMPANY 2*3 WEST 481* STREET «W YORK 2-8tsis 2-8 "HOW RADIO IS HANDLED IN THE - Atlantic Fleet OF THE United States Navy" A newsy article with fine exclusive photographs in next week's Ri\DIO WORLD No. 43, dated Jan. 20 ( RADIO-WIRE TABLES, BY FREDERICK J. RUMFORD, Ei, RJ. RADIO WORLO, I«> BROADWAY. NEW YORKJV. Y. A Neat, Compact Binder for Radio World We are in a position now to furnish RADIO WORLD readers with a neat compact and practical binder. This binder will hold one complete volume of RADIO WORLD ready for instant reference. Furnished to our readers or the trade for seventy-five cents each, net. \ We have only a limited supply of these binders. Address Sub. Dept, Radio World, 1493 Broadway, New York REPRESENTATIVE WANTED ONLY SPARE TIME NEEDED *TVrT7TATC In «fy Raw° World wants a representative to gtve i^ILf VV O *« tlu local radta news. Especially of the activities of the local Radio Clubs, new radio inventions, etc. CT TTDO/^T) TTyTPT*^\TVTO R*010 World ikjik has 70,000 read- OUOOI^JyIIT llWiNo «•'• We art mating a drive for a . .. ... , hundred thousand before the end of the year. Ninety per cent of our readers renew their subscriptions. A marvelously high average. Radio World, the national radio illus- trated weekly, is the oldest radio o .. . , ,. ., weekly, having the largest circulation. Radio manufacturers and distributors appreciate that Radio World is a most profitable medium to carry their trade notices. COMPENSATION J-«.vrS?A« . . commission. Previous experi- ence not needed, as we gtve our representatives full detail instructions and every possible assistance and help. Write telling us all about yourself— age education, business experience— and we will immediately give you full detents'. Telling you just how you can materially increase your income. DO IT NOW. RADIO WORLD 1493 BROADWAY NEW YORK CITY Digitized AlOOQlC ADVERTISING

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RADIO WORLD IF YOU ARE INTERESTED IN RADIO YOU NEED THESE BOOKS NEW RADIO BOOKS Telling How to Operate a Radio Set — How to Build a Set — Principles of Vacuum Tubes and Other Radio Problems Radio Hook-Ups Br M. B. SLEEPER A book that give* you sot only char atia- (rams for all kinds of telephone and tola- graph receiving and transmitting atta, bat aim pie description! of each circuit showa and •pacta for notes of results obtained. PRICE It*. Construction of New TypeTrans- atlantic Receiving Sets By M. B. SLEEPER There is a peculiar fascinstion about re- ceiving radio messages from the high- power stations of England, France, Car- many, Rossis and Italy, as well as those located in the Pacific Ocean and the Orien- tal countries. Several types of simple re- ceiving sets for this purpose ere described, with detectors and amplifiers to accompany them. Suggestions are also given for oper- ating relays and reproducing the signsls on a phonograph. Schedules of operating time for high-powered stations are given, la addition, there is some valuable data oa home-made wavemetera for testing and eg* perimenting .PRICE He. Wireless Telegraphy and Tele- phony Simply Explained Br ALFRED P. MORGAN One of the most complete and comprehen- sive treatises on the subject ever published. A study of its pages will enable one to master sll the details of the wireless trans- mission of messages. The suthor explains in simple language the theory and practice of wireless telegraphy and telephony. IM pages, 156 engravings .PRICE flM Design Data for Radio Transmitters and Receivers Br at. B. SLEEPER ■inner buys after ha baa learned the use of Bis phone receiver .PRICE He. Construction of Radiophone and Telegraph Receivers for Beginners * By M. B. SLEEPER The ssan who wants to feel the real thrill of accomplishment, and who is not satisfied in the merely making use of what others have done for him, builds his owa radio apparatus. Radio men can follow the data in "Radio Phone and Telegraph Receivers," with full confidence, because each piece of apparatus described was first made, tested and found efficient before the final design was accepted. Special receivers, both crys- tal and audion, are shown m detail. Regen- erative circuits as well as audio and radio frequency amplifiers are described with clear photos, diagrams, and working; draw- ings prepared especially for the navies sad the man who wants to receive the radio telephone broadcast. A apecial feature is the phonograph type radio set and the loud spesker. Fully illustrated PRICE Tie. The Radio Experimenter's Hand- book By M. B. SLEEPER Throughout the preparation of this book, . one purpose was kept in mind — Answer the Practical Questions of the "Novice," of the "Beginner, and the more advanced "Stu- dent." This book will help in the selection or construction of simple apparatus for the tranamiaaion and reception of radio tele- graph and telephone signals. In the chap- ters on radio receivers the simplest crystal, the simple audion, and the regenerative types are described in quite some detail. The question of antennas, both for trans- mitting and receiving, are taken up. A good many helpful suggestions are given which will be of considerable sid to the experi- menter. 16 chapters. Fully illustrated. PRICE Jl 00 The A BCofVacinmTubes Used in Radio Reception By F_ H. LEWIS Aesee. L R- E. aad Kasha laetiatas, Written particularly for the person was "knows nothing about radio" but was would like to gala aa understanding at the elementary principles of operatise si vacuum tubes and various circuits b) which they are used for the reception of radio-telegraph signals and radio- tskphoss music and speech. Illustrated. -PRICE SIM How to Make Commercial Type Radio Apparatus By at. B. SLEEPER This book describes in detail maay com- mercial types of spark and vacuum tuba telephone transmitting and telegraph sal phone receiving equipment of all kinds. The experimenter will be able to get s world of ideas for the design and com trac- tion of his next piece of radio equipment from the very clear descriptions aad the ft clearly illustrated figures...... .PRICE He Experiment*!. rvWlRElESSr- Experimental Wireless Stations By P. E. ED ELM AN Tells how to make apparatus to not on!; hear all telephoned aad telegraphed radte measages, but also how to make simple equipment that works for transmission over reasonable long distances. Then there is a boat of new information included. Tsa first and only book to give you sO the recent important radio improvements, soon of which have never before been published. 392 pages, 167 illustrations PRICE PJI ' " Any of These Books Sent Prepaid oa Rvceapt of Pric*. The 9 Books for $10 .M, to One or Different AJcb-easae. address XHE COLUMBIA PRINT ROOM 326, NO. 1493 BROADWAY, NEW YORK Digitized by Google

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15c. a Copy January 20 $6.00 a Year 52 N«bm Makes Remarkable DX Record without WEEKL Amplification ONE of the most remarkable records made by a simple crystal radio- receiving sot Has bosn recorded by William Keating-, ISIS Second Avenue, South. Mm noapotls, who, without any amplification, bears St. Louis, Louisville, Daven- port, Iowa, and Detroit. The average crystal set rarely receives over a radius of thirty miles. Mr. Keating'* apparatus is simple. His hook-up is similar to that used by most radio fans, with the exception of a specially wound tuning-coil with a double coil of wire primary and secondary. Two circuits are used, the phone condenser being connected In series with the secondary winding. Hie aerial is Se feet high and 7S feet long-. In addition to his remarkable long-distance record, Mr. Keating can bring in local stations with a loud-speaker. This, heretofore, has been considered im- possible with a crystal set without use of amplification. Another feat of Mr. K eating's is the use of his thumbnail in place of the catwhisker on his detector, which brings In the music strong In the headphones. Mr. Keating has contributed a letter to this issue of RADIO WORLD, fully describing his set. See "With the DX Nlte Owls," page U. (Photo C International) Build x Circuit with a Detector. See Page

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RADIO WORLD Praden Reliable Radio Specialties for Good Results! BESTONE Spring Grip Telephone Plug 11m Beotone Plug Is an en- tire ij radical departure In de- sign and construction, giving superior results. A simple pressure of the buttons Instantly connect* or disconnects the receivers. It Is not nteessery to disassem- ble the Bestone Spring Grip Plug for any reason. Just Insert the cord tip* — no mora work, worry, or possibility of a poor connection. ■Umlnatea the use of several plugs— eosMes you to use from one to three sets of telephone raoolTers, or to change from head phones to loud speaker, without disconnecting. £1 OC List fl.LD THE name "Pruden" back of standard Radio Equipment is a guarantee of mechanical excellence, perfection of work- manship and scientific correctness of design. Now, more than ever, when the market is flooded with inferior goods, it pays to buy standard trade marked products. You can pin your faith to "Pruden." Money- back unconditionally if you do not get complete satisfaction. Just one of the leaders of Pruden Reliable Products shown here that will give you better radio results at no greater cost. Everything sent P. O. B. Jersey City. Send money by registered mail, post office or ex- press money order. Dealers write today for our interesting proposition FREDERICK H. PRUDEN. Inc. 993 Bergen Avenue Jersey City, N. J. RADIO UP TO A STANDARD BUT DOWN TO A PRICE FOR M DAYS For those prices mention RADIO WORLD. All goods now, in oriental $4g.00 MAONAVOX i Type $32.00 XXX BAKELITE— K in. 7x10 (1.40 7*10.. .12.50 0'/,XIS.. 7«20...(2.80 7«24...t3.40 03.40 SOO.OO 6REBE C. R. 105.00 GENUINE NATHANIEL BALDWIN TYPE C TURKEY J, to.00 ON OHM HEAD SETS *X25 ATWATER KENT Transf ormcrg $4.00 Variometer* 6,25 Detector and One-Stage. . 1 1.50 2-Stage Amplifier 11.90 Mounted Varloeoupler I 1.50 PHONES Dr. SeiH .05.50 4.81 DIetetraesj . 4.00 4.000 Oea Freae*. Phen M 5.(5 "B" BATTERIES $5.50 45-Volt Eveready $3.85 3.00 22'i-Volt Eveready.. 2.10 4.30 45-Volt Franco 3.00 2.75 22'/,-Volt Franco.. 1.75 1.75 Burgee 22'/. 75 5.00 40-Volt Eveready . 2.00 PARAGON R. A. 10— 0. A. 1 $113.00 OREBI C. R. 0 (100.00 DE FOREST M. R. 0 0(2.00 Western Elertrl. Fewer Aatplifteel (118.00 FEDERAL CRYSTAL SET $0.00 Radio Frequency Transformers UV 1710 07.00 UV 1714 $.00 Baldwin 2.25 Aesw J »5 Erla 3.00 LOUD SPEAKERS Klao Her* $8.00 Dietaorsak 14.50 Baldwla Clsreskeae 14.00 Bristol Audioehoao 18.00 .17.00 TUBES OV 200 M-j; uv 201 WD- 1 I I'A-Velt 5.25 Meyers 4.00 De Forest and V. T. 2, In Stock RHEOSTATS Ratio Cere (2.40 Cutler Hammer 80 Murdeek 75 Paragon 1.20 VARIOCOUPLERS Baldwin $4.50 All Wave Capitol 7.50 Ernes 4.71 Tuska 2.50 Variable Condensers 23-plate Vernler(U.S. Tool) .$4.75 43-plato VernierlU.S. Tool) . 5.25 .0015 Balanced De Forest.. 5.00 .0005 Balanced De Forest. . 4.75 23-olate Moulded Ends 1.25 POTENTIOMETERS Radio Corp Paragon Graohite Amsco $1.75 1.50 1.20 1.15 RADIO SERVICE LABORATORIES R. T. (-$4.75 R. T. 0 A. RADIO FREQUENCY TRANSFORMER Space xeill not permit us to list all our special values, therefore ice will gladly quote special prices on any Radio Parts or sets you may want. Reliable merchandise first, than price. We will refund, at any time, tor Radio material pur chased from us which is not up to standard and as represented. No Checks. No C O, D. Add Parcel Post. Reference: Radio World. S77 MYRTLE AVENUE Phone Prospect 2952-8168 BROOKLYN, N. Y. Laughing In The Limit IT'S all right for a fellow to be a DX nite owl, and it's gratifying to the rest of us to know that there is such an animal, but there's a limit to every- thing— and that limit has been reached when a fellow writes in to say that at six one morning, eastern standard time, he heard a bedtime story in Chinese I * a » Write and Ask Him Dear Radio Editor: — Last night between 9:30 and 9:45, I heard music transmitted from a station whose announcer talked on 360 meter*. He was very faint but nevertheless clear. I did not get his call letters. • Could you tell me what they were, and who the announcer was — Ray Dio. * * a It Can't Be Done Dear Editor: — I have a boy fourteen years of age, Who has always been interested in me- chanical things and who is fond of read- ing imaginative books like Jules Verne's "Twenty Thousand Leagues Under the Sea." Just lately he became interested in radio. What can I do to discourage him? — Anxious. a a a Movie Fan Gets Mixed Up Dear Editor: — How long has OGN been operator at Newark, N. J.? How old is he and did he ever walk tight-rope with B & B? Is he married? Would he send me a pho- tograph if I wrote to him? — N. Raptured. Radio Saves Life of Sailor T> ADIO messages describe the saving of an American seaman's life by his transfer at sea from a freighter to the Italian steamer, "Conte Rosso," where an operation was successfully performed by the ship's surgeon. The "Conte Rosso" will arrive a day late, having gone more than 150 miles out of her way. The Lloyd-Sabruardo Company an- nounced the receipt of a radio from Cap- tain Fulvio Cignoni of the "Conte Rosso." Captain Cignoni said that he had picked up an S. O. S. from the American freight- er "Eastern King" in which a seaman was said to be in so serious a condition that he would die unless an operation were performed. The "Eastern King," running from Scotland to New York, was following a northern course while the "Conte Rosso" was on the southern lane. She was also .bound here. The Italian vessel shifted her course and reached the other boat. Despite heaving seas, the man was trans- ferred and his life saved by an immediate operation. His name was given as Rick Hubrinette. The "Eastern King" is owned by the Shipping. Board and oper- ated by J. H. Winchester of 17 Battery Place. COMPLETE YOUR FILES OF RADIO WORLD FOR 1922 of Radio World are tstemlne; scarcer all the time. We can now furnish jron wtta umbers for one etaeW. Ll4*=u No. 1 to date at fifteen cents a copy. Any eeran RADIO WORLD, MM Broadway, New York CJty King Sr. Variometer ISO to 900 meters. No outside eosa- nectina; hardware used — reducing- ca- pacity losses. Barged — Solid. Slxe **&"xt*&"xt" Guaranteed by manufacturer direct to user. Retail price tt.SO Aremeo tO 7 OB. ■ St.,N.Y.

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VOLUME TWO OF RADIO WORLD [Entered as second-class matter, March 28, 1922, at the Post Office at New York, N. Y., tinder the Act of March 3, 1879.] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4799. VoL II, No. 18. Whole No. 44 January 27, 1923 15c per copy, $6.00 a year H.B.Thayer Who Telephoned by Radio from America to England By Harold Day (C. Fotograms, N. Y.) Fa- Mr. H. B. Thayer, president of the American Telephone and Telegraph Company, talking from New York to England, by radlotaiepha two hours the ether over the Atlantic Ocean carried the human voice from New York to a croup of dbrtinguiahad official] at Now Southgate, England. The apparatus, which 'worked very successfully, was a result of co-operation between die American Telephone and Telegraph Company and the Radio Corporation of America. Mr. Thayer was heard by thousands of Englishmen, THE first transatlantic transmis- sion of the human voice by radio is now on record as a fact. H. B. Thayer, president of the Ameri- can Telephone and Telegraph Com- pany, 195 Broadway, New York City, and General John J. Carty, vice-presi- dent, in charge of development and re- search, have telephoned to a number of electrical engineers and radio ex- perts at New Southgate, England. The perfected instruments are not only commercially practical for trans- atlantic radio, but will be developed in the near future to the point of radio communication half way round the earth. The device which makes possible in- ternational communication across the oceans is a water-cooled vacuum tube, which increases the force of the radio transmitter from 1 kilowatt in the old apparatus to 100 kilowatts in the new. After Mr. Thayer had been speak- ing eleven minutes into an ordinary telephone transmitter, from which it was flashed to New Southgate, a cable came back, which read: "Thayer got through to all." Since the new vacuum-tube had not been sent to Eng- land return conversation was impos- sible, but the British officials, engineers and press representatives replied with extended cables of congratulation, attesting the complete success of the perfected instrument. ■ Major T.. F. Purves, engineer in chief of the British post office, after the first few messages had been sent, cabled : "I have listened with great interest and pleasure to the far-flung voices of Mr. Thayer and Mr. Carty. Of Mr. Thayer's message I recognized every word. I missed a little of Mr. Carty's, but recognized absolutely his well- known intonations. Send best re- spects and warmest good wishes to our friends in the A. T. and T. and the W. E. Co.— Purves." They talked into an ordinary telephone transmitter.

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4 RADIO WORLD The Single Circuit Regenerative Receiver Since the Release of the W-Dl 1 Tube, Many Amateurs Now Using Crystals Will Be Interested in Building a Single-Circuit Regenerative Receiver. This Article Was Specially Written for Those Considering Such a Set By C. White, Consulting Engineer A FRIEND approached me rer cently concerning the purchase of a radio outfit for his home. At the time I was at work on a five- tube reflex circuit to be used in some special test work; but the question, "What set is best for my use and will be capable of producing good results ?" made me stop and think whether the circuit I was working on was best for him, or a simple single-circuit re- generative outfit. The decision was. almost immediately in favor of the simple circuit; and I truly think that, for perhaps ninety per cent, of radio- phone and code amateurs who are just beginning their radio work, this answer will fit their case. Do not imagine that the single-circuit receiver is not capable of sharp tuning. The ability of any circuit to tune sharply depends .greatly on the care and scientific precision with which it is built and assembled. While it is true that the tuning characteristics of certain circuits are far better from the theoretical standpoint than others, still, if care in the purchase of good material and apparatus is taken, it is possible to get wonders out of the single-circuit regenerative circuit. I shall endeavor to discuss some of the points that will enable any one to build a simple regenerative-receiver that will not only work easily after built, but will bring in results that will make the owner proud. In Figure 1 is illustrated the stand- ard connections for a single-circuil regenerative tuner and detector. From the appearance of the wiring connec- tions this diagram is no different than any other for a single-circuit re- generator ; but by choosing the correct apparatus and the proper methods of construction we can make it different from hundreds of other similarly con- nected outfits. The condenser, C. should have not more than 13 plates. This allows a closer adjustment of the capacity in sharp tuning. The general tendency in the past has been to use too large condensers in the main tun- ing-circuits. The panel immediately surrounding the condenser should be well shielded with copper foil, which is connected to the ground terminal of the set. While shielding is generally very good, still the use of too much shielding greatly detracts from the strength of the received signal. For this reason many manufacturers prefer to wire up their sets so as to minimize body-capacity effect instead of employ- ing complete shielding. But it is abso- lutely essential to shield the panel in the immediate Vicinity of the con- denser. The main tuning-inductance, E, is the stator of a good molded vario- coupler. The tickler coil, F, is the rotor of the vario-coupler. I have found that the molded type of vario- coupler works a little better in a cir- cuit of this general nature. The grid leak and grid-leak condenser appear rather small in an illustration, but in reality they play a large part in the efficiency of the receiver. There is not only one correct value of grid-leak re- sistance and capacity for every type of vacuum tube, but there is one correct value for every particular tube. It is up to the amateur to discover this value for his tube by trial. A recent issue of Radio Wokld con- tained a very good article on the manu- facture of a reliable and variable grid leak. It would b£ well for the amateur to make one and place it inside his cabinet. It is also advantageous to try out various sizes of mica grid-leak con- densers. I specify mica because ffie capacity of mica condensers for grid work are sensibly constant, and thus work is sensibly constant, and thus free from noise. Start your testing with a .00025 mfd. mica condenser for the grid, then vary the grid-leak re- sistance until the best point is found. This should be repeated for another capacity of grid condenser, but for the average type of tube a .00025 mfd. will render the best results. A W-D 11 tube, with a dry cell for an A battery and at least 40 volts for a B battery, functions very well in a cir- cuit of this nature. Next to a vernier condenser comes a vernier filament- rheostat. Do not fail to incorporate a vernier filament-rheostat in your set The final tuning in of distant stations is invariably easier to accomplish with the filament-rheostat than with any other control in the whole outfit. The operation of tuning in a station is ex- tremely simple: Light the tube fila- ment to the correct brilliancy, set the Ant Figure 1. Standard connections factor. By choosing the it can be for a single-clreuft regonorattyo tuner and de- apparatu* and proper mpthodb of different from hundreds of ethers. Digitized by Google

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RADIO WORLD 5 How to Make a 2-Tube DX Set ACCORDING to the law of averages, by which everything is judged, after a man has been interested in radio for some time he itches, so to speak, to make his own receiver. If he happens to belong to the great army of radioists who hate only recently become interested in radio, due to broadcasting, no doubt he will consider this something of a prob- lem. "What circuit shall I use?" "What apparatus will I need?" ^ow can I do it?" are the principal ques- tions confronting him. I shall attempt to answer these questions in such a manner as will make it plain to everybody interested just how it can be done. I advocate that beginners use single- circuits in constructing their apparatus. And this not only applies to beginners, but to old-timers as well. The sketch accompanying this article illustrates the hook-up of instruments. It is a single-circuit, using a variometer as the tuning unit. This not only makes the tuning much simpler, but gives a definite wave-length. A list of apparatus necessary for the construction follows. The cost, (Continued from preceding page) switch-arm at a tap on the stator, adjust C until the station is heard, then adjust the coupling of the rotor, F, to get the maximum signal strength. Finally, raise or lower the filament brilliancy to get the desired quality. A good pair of phones with a .001 mfd. (C-l) bypass condenser is just as essential as any part of the receiver. Poor phones will cause more dissatis- faction than any other cause. I can- not too strongly advise the amateur, and particularly the novice, to buy good standard apparatus that has stood the test. If you are only planning on using one tube, and, perhaps, one tube for a detector and one for an amplifier in a one-stage audio-fre- quency amplifier, I think the W-D 11 is the most economical. With the money saved from the purchase of a storage A battery the novice can pur- chase another stage of amplification. But, if the W-D 11 is used, do not forget to mount the tube socket on of an inch of felt and connect up to the socket with flexible stranded wire so as to avoid the tube being noi^y from jars and vibrations. For the average amateur the single-circuit re- generative receiver without, or with, one or two stages of audio-frequency amplification is still the best buy. By John Kent jack. U. B battery, «-volt wttfc Btt-«ah tap. 11. W-D U tab**. This droit I* a i tioa d aaa «*M ant by Mr. Gaaraa May to RADIO WORLD Na. M, te tba aarial Ua4 baa baa frady, at lowar Ma— at teamaralwa. A let at tba raralai oi tba caadaaaar as dan wava-warfc. Tba variabk grid laab la < a aaeaaatty la tfab circuit, ada« W-DU of course, varies a few cents either way ; but the complete cost is estimates at $35 : 1 variometer $4.00 1 23-plate vernier condenser 3.50 1 43-plate straight condenser 2.00 2 W-D 11 vacuum tubes @ $5 10.00 1 vernier rheostat 1.2S 1 straight rheostat 1.00 2 sockets @ 75 cents 1.50 1 amplifying transformer 3.00 1 panel, 7x18 inches 1.58 1 cabinet 3.00 2jaclcs@$l 2.00 1 B battery (45-volW 225 $35 XX) With everything necessary pur- chased give the panel a thorough sand- papering. Then apply a little oil ; rub it in thoroughly and wipe off. This gives the panel a dull finish, which is much more commercial looking than one that is shiny. Next, on the reverse side, lay out the instruments in order to find out how much room is neces- sary for each. Carefully mark and drill the holes. In doing this be sure you are accurate, as one hole in- correctly drilled will make more trouble than if you had spent an extra half -hour planning it. If the drilling is carefully done and the instruments symmetrically laid out on the panel the finished article will be one you can point to with pride. When all holes are drilled mount the panel on a piece of 1-inch wood, as shown in the sketch. This piece should be two inches shorter than the panel and ahout one inch narrower than fhe depth of the cabinet. This will per- mit the amateur to mount his sockets and transformer and hook them up on the outside of the cabinet This give* much more freedom in the soldering. Follow your connections with bus bar or No. 12 or No. 14 hard-drawn copper. Be careful not to let any of them touch. All battery, aerial and ground connections are brought to binding-posts on the front of the panel. The hook-up used in this article has been thoroughly tested out by the writer and found to give excellent re- sults. Because of its extremely sharp tuning it is a little hard for the beginner to get used to it Da 5£" Digitized by Google

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6 RADIO WORLD First Story of Bureau of Standards Conference on Radio Standardization ABROAD program of radio standardization was agreed upon at a meeting of represen- tatives of forty radio-trade associa- tions and national engineering and scientific societies, held in New York City, beginning January 12. The meeting was held in the Engineering Societies Building, New York City, at the call of the United States Bureau of Standards in co-operation with the American Engineering Standards Committee. Dr. F. C. Brown, acting director of the Bureau of Standards, presided. After full discussion the confer- ence adopted resolutions providing: (1) That standards for radia ap- paratus and service should be formu- lated : (2) That a broadly representa- tive national committee on radio standardization should be formed under the leadership of the Institute of Radio Engineers and the American Institute of Electrical Engineers, under the procedure of the American Engineering Standards Committee. Specifications for quality and per- formance of receiving apparatus, no- menclature, and methods of testing and of rating apparatus are to be in- cluded in the program. Dr. J. H. Dellinger, chief of the Radio Laboratory of the Bureau of standards, showed how the widespread interest in radio had brought with it an increasing demand for uniformity and dependability in radio service and apparatus. The lack of any such standardization has been brought to the attention of the Bureau of Stand- ards by producer, distributor, and con- sumer. There has not previously been a concerted movement to intro- duce standardization by joint action of all radio interests. Dr. A. N. Goldsmith, secretary of the Institute of Radio Engineers, said : "As every new field of industry passes out of the childhood stage, the need for standardization becomes evident. The main difficulties which at once arise, and which emphasize the necessity for cautious procedure are the dangers of stagnation in an only partly developed art, a possible excessive monotony in the resulting product, and a diversion of the best brains from such a field. "On the other hand, it is only by a reasonable amount of standardiza- tion along wise directions that gross abuses of public confidence can be avoided. As a typical instance, con- sider the objectionable nature of some of the so-called 'information' appear- ing on nameplates and in the adver- tisements of radio apparatus. We have seen 'static eliminators,' 'thousand- mile receivers,' "twenty-plate con- densers," and a score of other vague or misleading designations. The pur- chaser of radio sets and the dealers who handle them are all entitled to protection against this sort of loose description. And thus we are brought face to face with the neces- sity for sane standardization." The following advisory committee was appointed to assist in the organi- zation of the national committee and the necessary technical subcommit- tees: Major L. B. Bender, Dr. J. H. Dellinger, W. A. Fitzgerald, Dr. A. N. Goldsmith, J. V. L. Hogan, Com- mander S. C. , Hooper, George H. Lewis, Max Lo wen thai, Donald Mc- Nicol, L. T. Robinson, M. C. Rypinski, E. B. Warner and L. E. Whittemore. Radio Entertainment in the Home WITHIN the near future madam, while at dinner, will instruct the butler, to push button No. 3 and ask Friend Husband if he pre- fers the opera to the jazz. He will probably reply that he likes a little J'azz, but prefers news bulletins while le is smoking his after-dinner cigar. Over in the corner of the dining- room stands a neat mahogany cabinet. It resembles a small victrola, with a single cord running to a plug in the base board. From this box come, alternately, as buttons 1, 2 and 3 are pressed, opera, jazz, or news — perhaps other forms of entertainment. There is no aerial lead, no inside antenna" coil ; there are no dials visible, and the many ugly details of our sets today are absent. No tuning is needed ; only the pushing of the buttons is neces- sary to select the form of entertain- ment desired. The three waves are constant and the service is on a regular schedule. All the above is not only practical, but probable. Line-wire broadcasting on electric-lighting systems, predicted and demonstrated as feasible by Major- By Patrick Nichols General George O. Squier, Chief Signal Officer of the United States Army, last March, has come true. At the Bureau of Standards recently R. D. Duncan, radio engineer for the North American Company, gave a practical exposition of "wired-wire- less" broadcasting over the system of the Potomac Electric Light and Power Company. At a distant sub-station in Georgetown an assistant "put on" in- formal entertainment through on ordi- nary broadcasting set over the 2,500- volt alternating circuit. Through the maize of underground and overhead wires and cables the radio messages came into the Signal Corps Radio Laboratory at the Bureau from an electric light plug. The voice of the spokesman was picked up by a tube set coupled in with condensers. A 5,000-meter wave was used, and the transmitting current was .05 ampere. There was no radiation. No other radio fans knew what was going on ; but, if they had, they could not have picked it up from the air — it wasn't in the air. Secretary Hoover will never have complaints of interference on this broadcasting scheme, as, being con- fined to the electric wires, it leaves the air clear for long-distance broadcast- ing; it needs no wave assignment, and neither the station nor operator will have to secure a license. General Squier's patents for directed radio have been purchased by the North American Company, New York, which owns and operates electric-light- ing utilities in Cleveland, Milwaukee, St. Louis, and several other cities. This company plans to furnish its sub- scribers with wired-wireless entertain- ment in the near future. Mr. Duncan is completing the details of a standard installation, and predicts the early use of the system in several cities. All that the subscribers will have to do is to consult their lighting companies, secure a good long-wave tube set, a condense*, or special plug, to protect their sets from the high-potential circuit, and plug in just as they do with common electrical appliances. General Squier's demonstration on a private lighting circuit of 110 volts direct current, nine months ago, has been applied to a city-lighting system. Digitized by LjOOQIC

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RADIO WORLD 7 My Rejector, or Filter, Circuit By Frederick J. Rumford, E.E., R.E. > j — Q M ^- — ■ t 1 t ' -awicxoi chodh X Fbjnra 1. Showfe* tha sasthod of In tha rector drcnH of tha nahki set The to toned until WnlinMi el to aecrea — 4 to a RADIO fans who have suffered interference in reception due to living in a locality infested with numerous transmitting sta- tions and other sources of QRM, will find the hook-up described herewith, a superior patience saver. It is known as rejector circuit, radio-frequency trap, and absorp- tion circuit. All hjave the same meaning. Many fans have worn their patience threadbare trying to get some long-distance station, but little spark stations have hammered in and destroyed all DX chances. The rejector circuit has proved very efficient, but I advise the prospec- tive builder to experiment first to find the proper number of turns of wire, the correct size of wire, also the proper capacity to be used for his individual needs. A coil wound with from 20 to SO turns of either No. 20 or No. 22 wire will do to start with. The condensers used should be of the common dielectric type. In many instances, fans living close to A-C power lines experience difficulty in receiving due to inter- ference from these power lines. To them the rejector circuit will prove of value and will decrease interfer- ence to a minimum. Figure 1 shows the method of connecting in the rejector circuit of the receiving set. The rejector cir- cuit is tuned until interference of the undesired station is decreased to a minimum. Then the receiving cir- cuit is tuned until the desired sta- tion is heard with maximum clear- ness and loudness. Registering for Radio (C. Wide World Pbotoi) MYSTERY. DOUBT. JOY! "Bun- Montana, fanaar wrestler and p Done Us Fairbanks la tha anta, mm *tly tha ban Uttaa by tha radio bus. Thto picture af Mr. Montana illustrates a sense onsotions that any athar human would experience, and humanly can-act. At Aral Mr. Montana is arystined an picking oa> tha earpiece*; secondly, ha has a raw doubt* as to its practicability; Anally, on tumiaf in riant, ha enjoys soma "hsdtims start**." This circuit is very simple to op- erate ; but one fact must be kept in mind: The rejector circuit should not be placed in any inductive rela- tion to any part of the receiving cir- cuit. If that is done, the rejector circuit will function poorly, if at all. It will be noted that the oscillat- ing circuit of this rejector circuit is connected directly, or conductively, with the ground lead of the receiv- ing circuit. If the radioist should attempt reception on the same wave-length as the interfering source , it is obvious that here is no means of separating the signals. But satisfactory results have been obtained on the rejector circuit when the signals were only a few meters apart in wave length. In a case where the signals from the sta- tion causing interference are very strong and the waves broadly tuned, and with no sharp defined resonant point on your receiving set, it generally is entirely impos- sible to entirely eliminate interrup- tion, but the intensity of interfering signals may be greatly reduced. It has been found that in some in- stances, it was possible to use a standard wave-meter in a rejector circuit which has an oscillating cir- cuit similar in every respect to the oscillating circuit of a rejector or trap. Those fortunate enough to own a wave meter and find it convenient to use, should employ it in the re- jector circuit. It has its advantage for all standard wave-meters are calibrated for reading directly the wave length of any adjustment. Figure 1 also shows the rejector, or trap, in function with the usual crystal rectifier. Figure 2 shows the rejector cir- cuit used in the usual audion vacuum-tube which is used also as a rectifier. This hook-up has also been tried and has proved efficient. Digitized by Google

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8 RADIO WORLD The Art of Proper Tuning By Kenneth M. Swezey A B CO Figure 1A— Conecting cell tn series to increase wave- length valvse BEFORE considering the actual mechanical operation of tuning it is quite necessary to under- stand the fundamental principles, otherwise this important radio process would have to be done in haphazard fashion. Dials would be turned and sliders moved without definite order. For instance, take the harp. The first thing we notice in that musical instrument is the difference in the thickness and the length of its strings. By plucking the various strings we find that they produce different notes — the long, thick strings giving out deep bass tones, and the short, thin strings the higher soprano tones. In reality these notes, or tones, are vibra- tions in the air of varying rapidity. We generally associate slow things with low tones, and large things are relatively considered slow. Speed suggests highness and shrillness, also smallness. Just so with sound waves : The long, thick strings of the harp vibrate slowly and give a low tone, whereas the short, thin strings vibrate more rapidly and give out a higher tone. The tension of the strings also affects their tone. Tight strings give out higher tones than slack strings. If we arrange another harp in the same room as the first — both harps having strings of equal thickness, length and tension — and pluck a string of one of them the corresponding string of the other harp will vibrate in unison and in a most uncanny fashion. When this phenomenon occurs the two vibrating strings are said to be "in tune." What has really happened? When one string was plucked it began to vibrate at a rate, or frequency, as it is called, depending on its length and tension. The air surrounding the string was disturbed and little waves were sent out into the room, one for each complete vibration of the string. It is these waves that reach our ears in the form of sound. They are actual mechanical movements of the air; so, when they come in contact with the other string, they push it and pull it and cause it to vibrate at the same rate as themselves. Other bodies are pushed and pulled by the sound waves, but the effect on them is not nearly so great as it is upon bodies that are "in tune." V i r Figure ZA— The simplest, practical In radio work we also have waves to deal with, but instead of traveling through the air they travel through a thinner medium, called "ether," and they are much larger than sound waves. But, however, they must be tuned the same as their companion air-waves. The transmitting station may be considered as one harp and the receiving station the other. The differ- ent transmitting stations send out waves of varying lengths. In order to receive them the receiving station must be properly tuned. Instead of tuning with length and tension, as in the preceding case, we have two factors called inductance and capacity. In a general sense we may consider our coils of wire as inductors F I ( u r • S— The two-circuit set which is quite popular and, aa a rule, more selec- tive than the sing le-clrcult type Figure 4— The meet popular angle-tube andiou set. It la known aa the two- variometer type regenerative aat or as possessing inductance in concen- tration, and our condensers as possess- ing concentrated capacity. The aerial system possesses both inductance and capacity, but in this case the values are distributed. " The frequency of radio waves is highest when the values of inductance and capacity are small; and, as fre- quency is the reciprocal of wave- length, a high frequency means a low wave-length. Therefore, short waves do not require as much inductance and capacity as do long waves. By connecting coils in series you increase the wave-length value. (See Figure 1A.) This result may be accomplished also by connecting a condenser in parallel to a coil. (See IB.) Condensers in series result in a reduced capacity, and, hence, a reduced wave-length. (See IC.) Condensers in parallel give an in- creased capacity. (See ID.) Let us now look at the different sets in common use and decide the best method of tuning. With a single- slider crystal set there is no option. Tuning must be accomplished by mov- ing that lone slider back and forth until the loudest signals are obtained. Figure 2A shows the simplest tuning arrangement that is practical and fairly selective. It is the two-slide tuning coil. The turns between A and B may be considered as the primary, or aerial circuit; and the turns be- tween B and C as the secondary, or closed circuit. The method of tuning is as follows : Place slider C at some arbitrary point on the coil. Now move slider A until signals are heard. An adjustment of slider C will now bring the signals in louder. With such a set interference may be minimized bv connecting in a loading coil. LC. When a station cannot be tuned out otherwise the effective coupling may be reduced by adding more turns in the loading coil and cutting out turns between slider A and B. The two-circuit set, shown in Figure 3. is quite popular, and is generally Digitized by Google

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RADIO WORLD 9 8 CYB, Heard in Manchester, England By Peter Gray (C. Wide World Photos) The transmitting apparatus of Station I CYB, Washington Court House, Ohio, recently heard in Manchester, England THE amateur broadcasting station 8 CYB is owned by H. E. Daugherty, the nephew of Attorney - General Daugherty. Mr. Daugherty, whose station is located at Washington* Court House, Ohio, re- cently transmitted to Manchester, Eng- land, by means of C-W signals, using the 200-watt transmitter, seen in the upper right-hand corner of the photo- graph. The man in the chair is the owner and operator. Mr. Daugherty has found it more interesting to ex- periment in radio than to enter politics. (Continued from preceding page) more selective than the single-circuit type. The variable condenser, PC, shortens the natural wave-length of the primary circuit, and may or may not be used. The secondary coil, S, is shunted with a variable condenser, SC. This condenser increases its wave-length. To tune: Set the secondary con- denser at a low value. Set the primary condenser at about the half-way point. Move the primary slider, or switch, until signals are heard. Now adjust SC until you get maximum response. If you do not experience any inter- ference the coupling between the primary and the secondary coils may be tightened, with a further increase in signal strength. A slight adjust- ment of PC and SC might now help. If interference is experienced the coupling should be loosened. The most popular single-tube audion set seems to be that shown in the cir- cuit Figure 4. This is called the two- variometer type regenerative set. The method for adjusting this is as follows : Have fairly tight coupling between the coils in the loose coupler or vario- coupler. Set both variometers at zero. Adjust the primary slider until signals are heard. Adjust the secondary variometer for maximum response. Next you must carefully adjust the plate variometer. By moving it toward maximum you will come to a point where a little squealing noise is heard ; moving farther you will come to a spot where there is another squealing noise. The proper spot is between these two squeals. Do not try to regenerate too much as this action will result in greatly distorted signals. Another type of regenerative set employs a tickler coil for the feed- back coupling. This set is adjusted in the same manner as the ordinary two- circuit set with the exception that the coupling of the tickler coil must be adjusted after the regular tuning is accomplished. For very close tuning with any of these circuits instruments known as verniers may be used. These are con- densers, or coils, of very small capacity that are used in connection with large condensers, coils, or variometers, affording tuning qualities between turns or between the points on a scale. Large coils and large condensers afford a great wave-length, and an in- crease in either will result in an increase in wave-length. Short wave- lengths require a reduced number of turns in your coil and a smaller capacity in your condenser. A con- denser in series with the aerial circuit will decrease its wave-length. Sharpest tuning is obtained with loose coupling. In the extreme left-hand corner of the photograph may be seen one of the receivers used in the station. It is a Paragon regenerative, with two steps of amplification. The amplifier is directly under the small loud-speaking horn. Next to it and directly back ol Mr. Daugherty may be seen the small transmitter used for local work. This is an advantage. When it is desired to talk short distances only there isn't the disturbance and interference caused if he had used the large 200-watt set Near the operator may be seen a Grebe regenerative receiver with amplifier and Magnavox loud-speaker. This station is an example of a well- equipped and well-handled amateur station. It illustrates the fact that the amateurs are right up to the minute in everything on the boards. It is not to be wondered at that the American amateur is so far ahead of his foreign cousin in radio when such a wide in- terest is taken in radio. New V. T. for Radio ANEW and improved vacuum-tube for radio— to be known as UV-201-A— . which uses but one-fourth the filament cur- rent of the present type radiotrons, has been perfected by the General Electric Com- pany. This tube may be used either as a de- tector or an amplifier, and it interchangeable in all receiving sets now using radiotrons UV-200 or UV-201 tubes. According to W. C. Whita who developed this new tube, its outstanding features are: 1. The filament current is but one-fourth that required for the UV-201, which means the storage battery will last four times as long without recharging. 2. Quieter operation; no tube noises. 3. Greater amplification due to greater filament and plate area. 4. Greater electron emission — about five times that of the present type tubes. Much less distortion c' Digitized by electron emission — ab the present type tubes

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B G of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks YT7HAT is meant by capacity t/lf when applied to a condenser? A condenser has unit capacity — termed farads — when a charge of one couloumb creates a difference in potential of one volt be- tween its terminals. This farad being too large for practical radio purposes the term microfarad (one millionth of a farad) is used. * * * What is a couloumb? A couloumb is the quantity of elec- trical unit. It is the amount of electricity passing a point in a circuit when a current of one ampere flows for the space of one second. * * * What is a farad? Farad is the unit of capacity. * * * What is meant by ampere? Ampere is the unit of flow and is that value of current maintained in a circuit having a total resistance of one ohm when actuated by one volt. * * * What is meant by ampere hour? Ampere hour is the unit expressing the quantity of current passing through a given circuit, or amperes flowing through a circuit in one hour. Thus to find out the ampere hour multiply the amperes flowing through the cir- cuit at any given time by the number of hours the current flows. * * * What are meant by damped waves as applied to radio? Damped waves are a series of oscilla- tions which gradually decrease in amplitude. The further the distance from the source of the oscillations' in- crease the more the amplitude decreases. * * * What is meant by undamped waves — continuous waves — abbreviated in radio to C. W.? The undamped waves do not decrease in amplitude in relation to the distance from the source of the oscilla- tions. * * * What is fading as applied to radio signals? Fading is a term applied to signals that slowly decrease and then increase in receiving power, though the power of the transmitted wave is constant. It is due to atmospheric conditions, and is common in spark (damped) wave signals. * * * What are the advantages of an un- damped transmitter over one of same power but using damped waves? In an undamped transmitter (C. W.) the waves are of constant ampli- tude, and there is no decrement. Con- sequently they are confined to one wave-length or frequency. Being con- tinuous the amplitude need not be so great ; therefore, lower potentials may be employed. Due to their being con- tinuous radiotelephony is made pos- sible as it will carry the modulations of the human voice. The tone may be controlled at the receiving operator's will. The efficiency is greater; and, as the decrement is nil, the wave radiated is much sharper. * * * What is meant by the term I. C. W.? The term relates to continuous waves that, due to the agency of an interrupter at the transmitting end, are audible in a crystal (non-oscillating) or straight audion-circuit. The in- terruption is generally caused by a buzzer or a tone wheel — a small metallic wheel, the periphery of which is either slotted or has a small metallic projection, which will serve to break and make the current rapidly when rotated at high speed. What does "modulation" mean when used in connection with radiotele- phony? Voice modulation is the superimpos- ing of voice tonal vibrations on the radio-frequency oscillations generated by the transmitter. Due to the fact that the voice vibrations vary in ampli- tude the modulating agency gives a corresponding rise or decrease in the amplitude of the transmitted wave. * * * How may undamped waves (C. W.) be received on a crystal or straight audion-set? By employing a small metallic wheel, preferably brass or copper, and pro- viding it with a sliding contact. This wheel is inserted in the detector cir- cuit. When rotated at fairly high speed the increase or decrease in re- sistance—due to faulty connections be- tween the rotating wheel and the stationary sliding contact — rapidly in- terrupt the current flowing in the detector circuit, making the undamped signals audible to crystal or straight- audion by interrupting the received signals. The Amateur Gets Wise By Harold Day IN these days, the unsuspecting amateur fully knows and appre- ciates good material, and will buy no other. Aside from the market and initial price consideration, there has been a general trend to cut down the operating expense at- tached to the maintenance of a large multiple tube-receiver. While it is true that the general high cost prevalent for tubes in the first place has prevented many amateurs from considering large installations, still I believe that if the ultimate cost of operating such sets were reduced and simplified, there would no doubt be many more large receivers. Radio World's Modest Aim RADIO WORLD from its very inception has attracted and held the interest of the radio public to such an extent that the pub- lishers have decided that everybody connected with all branches of radio— scientific, manufacturing— distributors, dealers, professionals, amateurs, factory workers, broadcasters, receivers, and all others in- terested in radio, are potential readers of this publication. Our modest aim, therefore, is to start a subscription and news- stand campaign that will bring everyone in the different ranks of radio workers into the RADIO WORLD fold as regular every-seven- *y Watch*"for sensational developments in connection with RADIO WORLD'S circulation during the coming months, and starting imme- diately. It can be done! Watch us do it! THE PUBLISHERS. Digitized by Google

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RADIO WORLD 11 KDYL, Heard by Many of the DX Boys mm $* " r r (Photo by Sainabury, Salt Lake) Station KDYL, aaacribad h tha •rttda. Mr. Ira bar, th. STATION KDYL is owned and operated by "The Telegram," Salt Lake City, Utah. This sta- tion uses the Heising system of modu- lation and transmission, and is one of the real "DX boys." Motor genera- tors are used to supply the high-plate voltage. They are located in a sepa- rate room and are controlled by the switchboard seen directly above the receiving set. Mr. Ira Karr, the op- erator-in-chief of this station, is checking up on the wave length of the station, a daily performance in most all of the most prominent broadcast- ing stations of to-day. The receiver, as will be noticed, is of the popular three-unit feed-back type using the well-known honeycomb or duolateral coils as the inductances. Take note of the extreme neatness and care that is taken of every instrument. This station is regularly heard over a dis- tance of 1800 miles in the following ., u holdbat districts: East, New York; North, Wrangle, Alaska; West, 1,800 miles out in the Pacific Ocean ; South, Mex- ico City, Mexico. The station oper- ates on a wave length of 360 meters for general program and 485 for weather reports, market reports, and other matter. The schedule for the station is 7 to 8 p. m., mountain time, every week night. It does not operate on Sundays. It is known to a large number of DX enthusiasts. The Care of the Variable Condenser. By Robert Clayton OF all the apparatus used by the amateur in constructing a set, probably none is more necessary than the variable condenser. But this apparatus, although necessary, generally receives less attention than any other. How many ama- teurs realize the fact that a con- denser may be short-circuited by tiny particles of dust which collect unnoticed between the plates, cut- ting the usefulness of this apparatus considerably. Sometimes, also, when the condenser is working hard, it is a common thing for an amateur to douse the bearings with oil. This is all very well ; but, if too much oil is used, it generally spreads and, eventually, collects additional par- ticles of dirt and dust,' forming a short cut for the fine currents and visibly cutting down the effective range of the set. I have evolved a set of simple rules, which I have been using with good results, re- garding the care of this particular piece of apparatus. They are as fol- lows : 1. Once a month, carefully blow the dust from the plates. Use a fine rubber tube so as not to bend the plates. 2. When the condenser is working hard, take a toothpick and a very little light oil, like sew- ing machine oil, and put just enough on the bearings to take the hard turn out; but not enough to flood the entire bearing. 3. Due to the fact that the bearings wear down, gently adjust the set screw, which allows the plates to be moved back and forth. 4. NEVER ATTEMPT TO STRENGTHEN PLATES IF BY CHANCE THEY ARE BENT while the condenser is on the panel. Remove it first. Digitized by Google

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12 RADIO WORLD Government's New Broadcaster, NAA, Has a Hard Time Winning Fans from NOF NOF has passed— the govern- ment's principal broadcasting station is no more. NAA, its big brother, has taken its place ; but many fans were disappointed to see the Navy's Anacostia Station return to research work. Some find it diffi- cult to get accustomed to NAA at Arlington and tune it in on 710 meters, the new wave assigned for government broadcasting from Washington. A hurried survey of the neighboring radio-population indicates how well they liked NOF; but it shows, also, that some must secure better sets or add a coil to old ones and learn to tune in on longer wave-lengths. Out of 83 replies, 61 who have picked up the station since January 3, like the trans- fer and" receive the music of tHfe Marine and Navy Bands well enough. Of those who object, 22 prefer NOF and the old 430 meter-wave. Favorable replies to an inquiry were received at NAA from New York" City; Manchester, New Hampshire; Worcester and Maiden, Massachusetts; Wilmington, Delaware, and Pittston, Pennsylvania. Some neighboring fans claimed the broadcasting was too loud ; others too weak. Fort Humphreys, By JV. R. Service Virginia, an Army station, approves the service as "fine." It is doubtful if the wave could be changed to a shorter one, due to the fact that short waves interfere with the regular waves used on other sets at NAA for handling official traffic for the government. But some consolation is found in the fact that the bands are playing at . the Marine Barracks in Washington, two or three rhiles away, and a single land- line is used for the transmission to the radio station. This will be improved by the installation of a special line, it is expected. Now the musicians play Wednesday and Friday nights in a barn-like room too large for the pur- pose and uncurtained. A sort of trans- mitting tent is being made, however, which will tend to restrain and con- centrate the music for transmission over the line to Arlington, which is certain to improve the concerts. Some rather frank expressions as to the preference for the concerts was expressed by listeners-in, who declared that some of the official talks broad- cast were a bore. Others complain of a hum and fading, and say NOF was perfect. Other returns have come to the Public Health Service, which sought to learn how its broadcasts from NAA were received by the radio public. Out of 100 replies over half declared they could not get NAA on the sched- uled nights, while 31 stated they got the broadcasts "O. K." The usual short-wave sets were found difficult to tune in on 710, but the sets built for longer wave-lengths gave less trouble. Generally the health fans prefer NOF. Sixty out of 80 declared that, of four large stations heard regularly, they got NOF best. It is regretted by the Navy that NOF had to be closed, but the work there was experimental, and other work must be undertaken. NAA is hardly "shaken down" as yet. One of the first duties of the Advisory Committee oh Radio win probably be to relocate wave-bands for all classes of service, ! including broadcasting, and it may be necessary to put some broadcasting up as high as 1,500 meters, which will make it neces- sary to add additional inductance to increase the range of wave-lengths of . receiving sets. White Radio Bill May Soon Be a Law THE amended White Radio Bill has been reported out on the floor of the House by Chairman Green of the Merchant Marine Com- mittee. As predicted, minor contro- versies were adjusted, ambiguities cor- rected, and the bill was printed Satur- day. No opposition is expected in the House, where the bill will probably be taken up within two weeks, it is said, by members of the committee. Secretary Hoover and Secretary Denby and their advisors have agreed to a compromise, and the bill now car- ries a clause that Army and Naval Sta- tions shall not require commercial licenses, that their wave-lengths will be assigned by the President ; but that, when commercial traffic is handled, rules and regulations designed to pre- vent interference with other radio sta- tions will be observed. In other words, governmental stations, when transmit- ting other than official matter, will use By Carl H. Butman commercial wave lengths' and comply with all regulations set down by the Secretary of Commerce. One feature of the bill increases the membership of the Secretary of Commerce's advisory committee from twelve to fifteen, including a represen- No Storage Battery Required A NEW type radio-receiving set with loud- speaker which operates entirely by dry cells and has an equal or better reception range than the average two stage set using storage batteries for the filament current has been perfected by the General Electric Company. It uses three of the new type GE tubes which consume sixty milliamperes filament-current per tube. The A battery, which is the storage battery in ordinary re- ceiving sets, consists of three dry-cells such as used for door bells. These supply the fila- ment current at 4'A volts. The B battery consists of four 22^-volt units which sup- ply ninety volts to the plate of the tubes. There is also a C battery, consisting of a small three-celle flashlight dry battery. tative of the Treasury Departmnet, an- other from the Shipping Board, and an additional member who is not a gov- ernmental official. The only cost to the applicant for an operator's license in the past has been the cost of an affidavit; the govern- ment did not charge for examination or permit, neither did it charge for sta- tion licenses. The new bill, as some may have forgotten, provides for a schedule of fees for station licenses ranging downward from $300 for a transoceanic station license to $2.50 for amateur transmitting stations. Operators' licenses will cost from $2.50 for commercial extra first-class operator's license to $1 for amateurs, with small additional charges for ex- aminations. These fees, it is planned, will aid in the payment of the Govern- ment expenses in handling licenses, in- specting stations and giving examina- tions. Digitized by Google

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RADIO WORLD 13 In the Radio Interior of an Atlantic Liner By Charles /. Taaffe Wide World Photos) The heart of the "America's" radio of the meet complete In deep era eorrice. IT will be remembered that the Atlantic liner "America" holds the distinction of being the first ■ of the gigantic passenger steamers to talk from mid-Atlantic to shore by radiophone. This was the radio sensation of the spring of 1922. It was the first time in the history of radio that telephoning by radio over a long distance was successfully tried. To-day is just another ex- ample of the tremendous strides that have taken place in radio during its first year. But what was considered as a miracle last spring is common- place now. Stations like KDKA and WDAP have been heard over 5,000 miles. Dr. E. E. Wood, of the "Amer- ica," is seen in the illustration diag- nosing a case of toothache on an- other ship and giving instructions as to the treatment. This phase of ra- dio, alone, is one that is never with- out human interest. Because of it, a sick man on a ship hundreds of miles away may receive expert med- ical treatment.' More than once, a man's life has been saved by the agency of radio. Although radio- telephony has taken great strides in a year, radiotelegraphy plays an equally important part. This is made evident by the panel directly in back of Dr. Wood. The complete radiotelephone equipment is seen on the extreme right of the picture, di- rectly in front of the operator. By use of the intercommunication ser- vice now installed aboard ships, it is possible for the captain of one ship to talk directly, from the bridge, to the captain of another ship scores of miles away and as easily as if he were at home and with less trouble than "central" would give him. In Radio World No. 45, dated February 3 Various Filament Resistances and How to Make Them By MARIUS THOUVAIS General Secretary of the Radio dub of Cetonce With sixteen working diagrams to guide the radio amateur in construction. One of the many big features of next week's Radio World Digitized by Google

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14 RADIO WORLD t RADIOGRAMS The Latest Important Radio News, from the World Over, Briefly Told for the Growing Army of Radio Fans FRENCH authors ar« urging ■ radio copyright on book* that are broadcast. The latest problem in the copyright- ing of literary works, especially of fiction, concerns the rights of the author when his books are broadcast to the public by radio. Today there are the book rights, the serial rights, the rights of translation, the rights of dramatization, and the moving-picture rights. To these must now be added, France's literary men declare, the radio-broadcasting rights. The matter has been brought to the attention of the Society of Men of Letters by M. Joseph Renaud, who urged on his colleagues the necessity of authors reserving and protecting the broadcasting rights in contracts with publishers, particularly in the United States and other countries which are "up to date" in the use of radio. » '» * With an Armstrong superregereaatiTe sat Benedict Gold- man, of 330 East Eightieth Street, New York City, believes that he heard a French amateur station during the amateur tests recently concluded. The message, which was received on a wave-length of ISO meters, was, "French amateur testing. Hello, U. S. A.," and was signed "8XD." Mr. Goldman is an experienced operator, having been in charge of the radio installation on board the Slav City during the World War, and was also stationed at the Brook- lyn Navy Yard. In his spare moments he directs the activities of the Federation Settlement Radio Club, at 106th Street, near Lexing- ton Avenue. • * * Radio broadcasting in the United States is now heard in all parts of Mexico. Even stations on the Atlantic Coast are clearly heard. President Obregon is an enthusiastic radio fan, a set now being installed in Chapultepec Castle. Secretary de la Huerta has ordered a set installed in his home near the lake in Chapultepec Park. * * * Official* of the General Electric Company have Just announced the successful conclusion of their carrier current experiments in telephone communication, which appear to be something like the wired-wireless system. According to an announcement the G-E engineers have communicated over a 70,000- volt transmission line for a distance of forty miles, using apparatus similar to a radio outfit. For power companies, it is said to have many advantages over ordinary land-telephone lines for communica- tion purposes. Carrier current, it is claimed, insures greater perma- nency and privacy, eliminates static, interference and fading, and does not require a radio operator. * * • The operating department of the Radio Relay League* from final figures just compiled, reports the following amateur stations, located in the extreme Western States, heard by amateurs in Europe during the transatlantic amateur radio tests just completed : Arizona: 6ZZ — H. L. Gooding, Douglas. California: 6AV— P. T. Nesbit, 625 Fitch Street, Healdsburg. 6ADG — F. Noel, 301 West Avenue Forty-three, Los Angeles. 6KA — F. E. Nikirk, 1050 West Eighty-ninth Street, Los Angeles. Utah : 6ZA— Ira J. Kaar, Salt Lake City. * * * For the first time in South America a demonstration of point- to-point radio communication has been made, according to a cablegram received by G. E. Pingree, vice-president of the Inter- national Western Electric Company, from Colonel N. H. Slaughter, one of this company's chief radio-engineers, now at Rio de Janeiro. Point communication is distinguished from radio broadcasting in that two-way conversations are carried on between two stations equipped with both transmitting and receiving apparatus. * * * Several scenes from the performance of The Old Soak* at the Plymouth Theater, New York, were broadcast by radio from WJZ. The question of whether a dramatic performance would be benefited or injured by broadcasting was answered on the following morning at the Plymouth, according to box-office men. It was declared that, up to 11 o'clock a. m., four patrons had bought tickets, declaring that they had been actuated by die radio record of the night before; inspired by the applause which registered through the receiving apparatus. The transmitting device was hung over the proscenium arch. Broadcast Sill's Radiolays By William E. Douglas IN these chilly winter ev'nin's, 'fore it's time to go to bed, how I like to sit and listen, rubber ear-muffs on my head, to the singin' and the speakin' comin' in by radio; weather don't make any difference — let 'er sleet, er hail, er snow. While I'm list'nin' there so peaceful to the music from the air I kin also get enjoyment in a game of soli- taire. I like most a game of canfield ; there are others I kin play, but I never knew it had a name until the other day, when a drummer down at Perkin's store explained how it wuz done in those classy gamblin' joints where they don't play jest fer fun. You hand out yer fifty dollars, or I guess it's fifty-two, then a gent gives you a deck of cards, an' after you are through fer each card up in the ace now he will hand you back five beans. Gosh! I like the game much better, now I've found out what it means. So when wifey goes out callin', leavin' me at home alone, I get out- a deck of cards an' play there by my radi'phone. It combines my fav'rite pastime, an' the times goes by so fast that the clock soon strikes nine-thirty, an' I know my bedtime's past. So I play another hand er two while waitin' fer the time that they broadcast out from Arlington before I start my climb. Sweet Minerva, that's my better half, re- ligiously inclined, hasn't took so very kind- ly to my habits, so I find just be- cause on Sunday ev'nin when she went in town to church I said I'd stay at home an' listen— kinda left her in the "lerch. That wuz not the only reaspn. fer while workin' Saturday I had sprained my back most awful loadin' up some bales of hay. So she went to church with Willie — I Vjayed home to listen in an' I reckon she'd ferf ive'd me if it only hadn't been. I'd fergot that it wuz Sunday an' wuz playing solitaire as I listened to the choir, an' the sermon from the air. Mtn came home an' caught me playin' — I kin tell the Universe when it comes to home- made sermons Sweet Minerva ain't so worse. Now I'll sit these winter ev'nin's 'fore it's time to go to bed an' do nothin' else but listen since Minerva's say is sed. Copyright 1922, Weatlnghouse Electric a Manufacturing Company. Digitized by Google

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RADIO WORLD 15 Radio and the Woman What the Great Game of Radio Brings to a Woman Who Has a Set in Her Home By Crystal D. Tector IT is surprising how many young folks have taken to radio. The younger son of a very dear friend of mine had become addicted to loafing about town in various places. His mother worried, fearing that his associates were not having a very good influence on him. For his birthday, the boy received a complete radio-receiving outfit Since then, he has become so interested in it that he has never so much as asked to join his old associates. Instead, he has joined a radio club and even holds meetings up in his "radio shack," as he calls it. * * • FRIEND Husband came home very excited the other evening — was so wrought up that I really cduldn't make any sense out of the erratic convolutions of his speech. Finally, when he had worked off some of his extra excitement, he was able to make me understand that his "boss" is about to install a large receiving set right m his office! "Gee I that will be something like it I" exclaimed F. H. "I have been pestering him for the past two months. I guess having him up here for supper last Sunday wasn't such a bad idea, after all— was it?" Well, I see where I can go back to pre-radio days and wait for him to come home to supper again— but at least 111 know where he is. * * * T T is the easiest thing in the world for one who doesn't know _ anything about the construction of radio apparatus to absolutely ruin a set in five minutes trying to "fix something." It took an expert probably seven or eight hours to assemble and test everything m the set and put it in working order. Why try to adjust it further when you do not understand it? Save money and time by having some one "fix it" who understands. This little stunt was firmly imbedded on the writer's mind the other evening: I had been visiting a man who had just become interested in radio. We went into the parlor to talk with his family. When I left the room the set was working perfectly; but due to the fact that his B battery was failing, it was not steady — the set was noisy. All of a sudden there came a disgruntled yell from the region of the house where the set was located. Going up I found the owner of a "once-was-good" set with a large screw- driver in his hand and a surprised look on his face contemplating the wreck. He had tried to tighten "something" and had received a slight shock, which caused him to remove his hand suddenly — also the glass of the bulb and half a dozen connecting wires. Moral: If you don't understand what you are doing leave it alone until somebody who does can fix it * » • MR. and Mrs. Tector have received an invitation to the "First Radio Ball in the Country." It states that the affair is to be a "Bal Masque," with costumes representing some piece of radio apparatus. He was highly insulted when I told him to dress up as a vario-coupler because he is so "changeable." He retorted that I had better dress up as an amplifying set because I always try to make the most of things; but I will fool him and go as a crystal detector. * » * """ ' 1 VHE Ladies' Society of our town has inaugurated a radio club, ■*■ with a class for those who do not understand the principles of radio. Lectures are to be given by the physics and science pro- fessor of the high school All my friends are attending, and have nominated me president I really do not know how I am going to spend all my spare time, what with radio clubs, radio classes, and a hundred other things, besides looking after Friend Husband and the house. I really will have so much time to myself that I will have to feed F. H. on bacon and eggs three times a week. * • * MOW that the radio clan is sharply divided between radio-fre- ^ quency and audio-frequency Friend Husband and I have some wonderful arguments as to the efficacy of both. He staunchly defends radio-frequency because he can always get it working better than I can; but it is too complicated for me. I stick to the old audio-frequency. It's simpler to handle and fix. * • » THERE have been several occasions while in the city when I noticed that more and more, things are ibecoming adapted to radio in general. Only the other day 1 noticed that the car of a certain party well known in theatrical circles had a complete work- ing radio set installed, and the concert from WJZ was coming You Must Be in Style! VARIO- £ouput\v B. Hlmeklay through the window of the car. Seems as if we will soon be able to keep in touch with radio even while we are traveling under the dry in the subways. * * * I HEARD the other night over the radio, that the station at Atlanta, Georgia, is giving a box of candy to the first person in every state who hears the station and reports. Too bad I didn't know that when they first started. I like candy. * * » A LITTLE girl met me on the street the other evening about half-past bedtime, crying her eyes out I stopped her and asked her what the trouble was. Sobbing her little heart out the said: "I-I-I tried to f-f-fi-ind the p-p-o-poor l-l-little b-bunny t-t-that got l-l-losted in the w-w-w-woods by Unc-Unc-Uncle W-W-Wig-Wiglies hou-house, and I-I-I'-m-m l-l-losted. I-I want m-m-my m-m-mama l" Poor little bunny was lost and so was the little girl who was looking for him. So I took her to my house, called up one of my friends, who has a local broadcasting station, and asked him if he would be kind enough to announce the facts over the radio. Inside of a half an hour the mother and father appeared and told me that they didn't even know that she was out of the house; that she had been told to go to bed about an hour and a half ago ; and, as she generally goes to bed herself, they didn't notice that she had gone out They thanked me a million times; but I think that they had better thank radio. Digitized by Google

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RADIO WORLD = 1 Monster Radio Tower Installel The Country's Biggest Broadcast- ing Station on the Roof of Aeoli- an Hall, 42nd Street Between 5th and 6th Avenues, New York City, Is Nearing Completion. One 12 Ton Steel Tower is Completed. WORK has just been completed on the first of the two 100-foot 12-ton steel towers on the roof of Aeolian Hall, one of the big skyscrapers on 42nd Street, just west of 5th Avenue, New York City. These masts will be used for the most powerful broadcasting station in the United States — WJZ. When the other tower — one similar to that used to illustrate this article — is completed, which will be about March 1, this new station of the Radio Cor- poration of America will begin to broadcast the concerts given in the building, for Aeolian Hall is a home of music. Recitals are given almost twice daily. It is then seen how easy it will be for the station to broadcast all the famous artists' concerts, symphony orchestras that take place in Aeolian Hall. On the sixth floor of Aeolian Hall there has been con- structed a special room for the regular radio-concerts. The walls of this room are packed over two inches thick with felt and other "noise killers." The floors are of a special rubber and cork composition laid on felt to deaden all ex- terior vibration, and all corners are rounded, to insure per- fect acoustics. The broadcasting room was designed by an acoustician and will be the most perfect broadcasting room in the world. There is a strong possibility that this station will operate on two different wave-lengths, sending out chamber music, and orchestral selections on one wave, and popular music on the other, simultaneously. It may replace WJZ alto- gether. Because of the great weight of these immense towers and the fact that this particular section of the city is honey- combed with subways, it took months to perfect some way to relieve the weight of the structure from the immediate building. This was finally accomplished by the use of a special steer- foundation attached directly to the steel frame- work of the building. The weight of these towers is dis- tributed in such a way that the sides of the buildings bear most of the weight, but not so much that the building has any chance of being endangered. This construction is the first of its kind to be attempted — and not without consider- able danger. The building itself, after the manner of all tall buildings, has a "give." By this it is meant that the structural Work is not firmly rigid. If such were the case, the first strong wind of any high velocity, or the first shock, such as a strong blast, would endanger the building. The building is constructed so it will sway, or give. This pre- sented a serious problem to the builders of the station, one which had to be overcome in such a way as would make the i — iii; — r ~1 The photograph at the left shows two of the worker* putting the finishing touches on the massive towers of the Radio Corporation ad America's new station, on the roof of Hall. Imagine working in the bitter cold, 35* feet above ground, and over IN feet above the roof— working an a slim iron framework, which, on these cold, snowy days, become iet coated and slippery. It is not the most pleasant job in the world, and it certainly take* a lot of nerve. But the manner in which the steeplejacks and steel workers climbed about gave the writer the impression that they did not mind the height any more than if they were walking on the ground. The photographer who snapped thai was invited to roam around the top crosspiece, and he remarked after the experience, "Never again r As msy be seen, the towers are constructed to form an equilateral triangle with the point of the triangle facing the direction of the greatest strain, namely towards the second mast. This is done to relieve any possibility of either mast buckling, as the strongest part of a triangle, when there is a pull on it, is at the peak. There will bo utilised, also, a heavy wooden pole, to act as a mast far the lowering and raising of the (C. Underwood & Diniti

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RADIO WORLD on Roof of New York Skyscraper By Robert L. Dougherty tower absolutely safe. While the base of the tower is much wider than the top, the entire tower would be endangered if it were not properly designed to take the "give" of the entire building, in case it were too rigid, there would be great danger of it breaking in two or ripping up at the base. This gives an idea of the situation the builders were com- pelled to face in order to insure absolute safety. In order to get an idea of the monstrous size of the tower, compare the man crawling up the side of the ladder with the width of the tower itself. This tower can be seen from New Jersey when the air is not cloudy. It looks like a monstrous finger pointing into the heavens. From the street below, the men working on the tower look like flies crawling about a gigantic web. (C Kadel L Herbert) One of the hundred-foot towers. A photograph taken the massive structure from the base of (C Kadel & Herbert) Aeolian Hall ia twenty-four stories high. Situated in the heart of the busiest section of the world, it is ideal as a location for a broadcasting station. The building, one of the highest in the locality, will give the aerials of the new broadcaster a clear and open range without any obstruction. From the mechanical side of broadcasting, so to speak, the location is ideal; but the public will be benefited because New York, being the roecca for so many who can add their gifts to broadcasting programs, will not be inconvenienced by a trip to another city. The building of this station marks an epoch in radio. There has never been much importance attached to radio, in the mind of the layman, but this venture, the first of its kind, attests the wonderful thing radio has become in the past few years. Had anyone predicted five years ago, that millions of dollars would be spent on radio and stations such as the one pictured on this page would be made possi- ble, he would have been considered a madman. But the impossible is being accomplished. How long before cities will be dotted with masts and stations like the one pictured herewith — each capable of talking to stations ten thousand miles away? It is only a matter of time. The location of this station makes it particularly adapt- able for long-distance work. Being in a section of high buildings — the massive aerials topping them all, with the possible exception being the Woolworth Building, five miles away — suggest possibilities of remarkable DX accomplish- Digitized by Google

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18 RADIO WORLD With the DX Nite Owls Similar to E. A. Wright's Hook-up From Fred Morton, PreeMent, Flathead WE wish to submit a report of the re- sults we have obtained using a hook- up very similar to the one described by Mr. Earl A. Wright in Radio Would, No. 39, dated December 23, 1922. We receive many western stations, and going farther we hear St Louis, Chicago, Dallas, Fort Worth, Houston, Atlanta, Duluth, and a number of other high-power stations. We once heard KDKA; once WEAF, New York City; three times KDYX, Honolulu, and once WGAD, Porto Rico. This is by no means a complete Hst of even the high-power dis- tant stations. After reading the article by Mr. Wright, one of the club members tuned in fifteen stations in thirty minutes. The hook-up we use is essentially the same as that used by Mr. Wright with these modifications : 1. We find that a variable phone-conden- ser, rather than a fixed condenser aids greatly in tuning. 2. We use a grid leak. 3. We use a variometer, connected as a vario-coupler. The variometer is wound with No. 20 wire, the stator is used as the prim- ary, and the rotor as the tickler. 4. Negative A and negative B are con- nected, instead of positive A and negative B. 5. The primary condenser has a capacity of .001 instead of .0005. 6. The grid condenser has a capacity of .00025. As Mr. Wright has explained, the tuning is done with the tickler half way between minimum and maximum, the rough tuning is done by means of the primary condenser, the fine tuning by means of the phone conden- ser, and, finally, by means of the filament rheostat. Using this hook-up, we have received sig- nals as loud and, in. many cases, louder than either the Paragon or Grebe sets with one- step of amplification. We can also tune in many more stations in an evening and with very little trouble. Using 3 power-tubes for audio-frequency amplification, with 45 volts on the plates of all tubes, and with a Baldwin Type-C unit as the loud-speaker, we receive music and phone so loudly that it can be understood 800 yards from the apparatus, near the cen- ter of the city. We shall be glad to receive letters from other clubs or '%ugs." The Flathead Radio Association, Kalispell, Montana, is the Radio Club of the Flathead County High School. We are entirely sur- rounded by high mountains. * * * Good Radio Work From R. Diamond, 413 Royal Street, Now Orleans, La. I HAVE written to you before regard- ing the stations I have heard; but since then I have added fifteen more to the list All have been heard on a single- tube regenerative set. The stations and the miles by air-line are: KHD, Colorado Springs, 1,000; KHJ, Los Angeles, 1,650; KLZ, Denver, 1,050; KSD, St. Louis, 600; KUO, San Fran- cisco, 1,875; KPO, San Francisco, 1,875; KYW, Chicago, 850; PWX, Havana, 1,000; WBL, Anthony, Kansas, 700; WEY, Wichita, Kansas, 700; WGM, At- lanta, 450; WGY, Schenectady, 1,050; WHB, Kansas City, Missouri, 700 (re- ceived best); WJZ, Newark, 1,150; WKY, Oklahoma City, 400; WLK, Indianapo- lis, 750; WOK, Pine Bluff, Arkansas, 300; WOS, Jefferson City, Missouri, 600; THE Editor of RADIO WORLD will faa pleased to neat** sketches of hook-upa from the "DX Nite Owls" who sand m records with a vtsw of publishing them. Send hook-ups of your sets, provided they contain ■omothma; unusual- Send, also, the names of the various makes of apparatus yon are using. Make your letters brief and mformatlve* Write on one side of the paper only. The letters and hook-ups will be pub- lished in the earliest possibls numbers of RADIO WORLD. WPA, Fort Worth, 500; WPM, Wash- ington, D. C, 1,000; WRR, Dallas, 450; WSB, Atlanta, 450; WWJ, Detroit 1,000; KDKA, Pittsburgh, 1,000; WAAD, Cin- cinnati, 750; WLW, Cincinnati, 750; WBAP, Fort Worth, 500; WCAE, Pitts- burgh, 1,000; WDAG, Amarillo, Texas, 800; WDAJ, College Park, Texas, 450; WDAL, Jacksonville, Florida, 500; WDAP, Chicago, 850; WEAO, Colum- bus, 810; WFAA, Dallas, 450; WEAF, New York, 1,200; WFAV, Lincoln, 875; WHAS, Louisville, 650; WKAL, Orange, Texas, 225; WLAC, Raleigh, North Car- olina, 800; WLAH, Syracuse, 1,180; WLAJ, Waco, Texas, 430; WMAC, Cazenovia, New York, 1,200; WMAQ, Chicago, 850; WMAT, Duluth, 1,200; WLAG, Minneapolis, 1,100; NSF, Ana- costia, D. C, 1,000; WFAT, Sioux City, South Dakota, 1,025; WOC, Davenport, Iowa, 825; WEAB, Fort Dodge, Iowa, 900; WOI, Ames, Iowa, 900; Portland, Oregon, 2,215. These stations come in pretty regu- larly. * * * An Unusual Circuit From J. L. Wiley, Jr, StnWnrt, Arkansas I HAVE been reading the DX records in your fine magazine ; and as I have been doing some DX work lately, some of the DX owls may be interested in my record and hook-up. I think my hook-up is a very useful one. I have never seen another like it A- Hook-up used by Mr. J. L_ Wiley m My long-distance records are KHJ, Los Angeles; PWX, Havana; WGY, Schenec- tady; CHBC, Canada; KDKA Pitts- burgh; WDAY, Fargo, North Dakota; WFAU, Boston; KFAF, Denver; WLW,. Cincinnati; KDN, San Francisco; WOAI, San Antonio, Texas; WOR, Newark; WLAG, Minneapolis; KDYL, Salt Lake City; KLZ, Denver. These are just a few of the stations I have heard, not only once but several times. I am enclosing hook-up which I use in this set You will find that it resem- bles the Flewelling in that both of the grid leaks are very particular. I use a piece of cardboard with pencil marks on its, as a leak. It took me about an hour to get leak No. 2 to work; but when it did, it was worth all the trouble. To make the set work: First hook-up coils in regular manner shown, but leave out leak No. 2 and two .001 fixed conden- sers. Next hook up condenser and leak. When first hooked up they will not make any difference in the working of the set, but careful adjusting of the two leaks will soon enable one to advance rheostat, and burn the filament brighter without making tube oscillate as rapidly as before. Condensers are not critical. Primary, 35 turns; secondary, 50 turns; tickler, 75 turns. After getting set to work with condensers in circuit, most of the turning may be done with secondary condenser which should have a vernier. Use very close coupling and most of capacity in primary condenser. Use a V-T one tube with 25 volts on plate; a U-V 200 with 18 volts, or a U-V 201 with 60 volts. U-V 201 will give best results as grid leaks will not be so particular. * » * My Six Months' Record From Russell Sheeny, NewBelda, New Hampshire THE following stations were received dur- ing the past six months on a home-made, single-circuit set KHJ, Los Angeles, comes in on one tube : California (2), South Dakota (2), North Dakota (1), Colorado (1), Oklahoma (3), Texas (8), Louisiana (2), Florida (2), Wisconsin (4), Utah (1), Kansas (1), Georgia (3), Nebraska (1), Il- linois (4), Michigan (4), Missouri (3), Indiana (2), Ohio (7), South Caro- lina (1), Norm Carolina (1), Minnesota (4), Iowa (3), Alabama (1), Tennessee (2), Maryland (1), Virginia (2), District of Columbia (4), Delaware (1), Pennsyl- vania (15), New Jersey (11), New York (16), Connecticut (4), Rhode Island (4), Massachusetts (9), Maine (2), Vermont 2), New Hampshire (1), Cuba (1), Porto Ico (2), Canada (4). This makes a total of 144 stations in 38 states and territories. I Need a Life Belt? From Parkins Bennefan, tST Poplar Are, Fresno, California. WISH to add to my record, published in Radio World. Using but one tube, I have heard the following stations: QSA, WGY, PWX, WSB, WGM, WDAJ, WWJ, WCX, WDAP, KYW, KSD, WX, WMAT, WLAG, WOI, WHB, WDAF, WFAA, WBAP, WFAT, WKY, CFCN, KFBB. The only stations on the list which I hare not heard at least twice are PWX, WMAT, WFAT and KFBB. There are 22 of them, fans, and all over 1,000 miles. Seven are 2,000 miles or more. The nearest is KFBB, 1,025 miles; the furthest, WGY, 2,500 miles. Let's see if you can beat this record, DX owls I Mr. Smith, I sell first-class life belts for only $5.95 ! * * * Adds 2-Stage Amplifier From C C Nedy, Box 2SS, Manor, Pennsylvania. I AM using a three honeycomb-coil hook- up. I am about twelve miles from KDKA and get their concerts loud enough to be heard all over the house with a Bald- win type "C" phone and one U-V 200 tube. The .0005 variable condenser, shunted around the phones, provides a good smoothmg-out Digitized by Google

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RADIO WORLD 19 Radio Receiving Set of U. S. Army The type 3C R 75 Receiver at print used by the United State* Army in its airplane service throughout the country. A close inspection of this photograph indicates that several novel features are incorporated in this receiver that mlfht be successfully utilised by the pro- gressive amateur who constructs his own apparatus. One of the most important to the switch — the second from the right. By means of this switch, all Jacks and plugs are eliminated. It to evident that you can leave your phones connected Into the set and by the mere push or pull of a small switch, automatically the amplifying circuits are connected into the circuit. This wiB call the inventive genius of the constructor fato play. Note that the receiver to constructed as to be rigidly fastened to the framework of the cockpit where it Is used. In order that no more vibration than is absolutely necessary Is produced, there are heavy gum- rubber washers, and gaskets fastened to the sides and back where It to to be fastened. Take particular note of the method of keeping the corner of the front panel-screws securely fastened by means of little pointed springs. With the DX Nite Owls (Continued from preceding page) effect. I sometimes add a two-stage ampli- fier which brings- in long-distance stations, loud and clear, through the load-speaker. I get the best results with three 50-turn honeycomb coils. It requires a good ground. I could not get sharp tuning with a water- pipe ground; but by burying a copper wire of several feet, directly beneath the antenna and combining the two, I can tune very sharply. Nova Scotia Seems Ideal By Owen C Frame, Gay's River, Nova Scotia. WITH a simple single-valve hook-up, I have heard die following stations: WJZ, WBZ, WGY, WOR, NOF, NSF, 233, WOO, WIP, KDKA, WIK, WAAM, CHAC, WGL, WRP, WHAY, WHAM, CFCA, Toronto; WBAP, WGM, WSB, WBU, WHB, WBAM, CFCF, CKAC, WLV, WGR, WBAN, WBY, WFI, WEAM, WWJ, WBF, WEAK, WNAC, WWZ, WEAF, WHAZ, WMAK, PWX, WKAQ, WDAF, WZAE, WLKA, WMAF, WAAF, WMAC, WLW, WHAS, WHB, KFAF, and WBAP. I do not claim this as a record as other amateurs nearby are doing practically as welL This district, thirty-five miles north of Halifax, seems to be an ideal location for receiving. During the warm weather in August, I heard WJZ and WGY, consis- tently using a crystal receiver. Since the cold weather, WGY, WJZ, WBZ, WTP, WOO, WOR are heard easily with crystal, and on one occasion NOF and KDKA. With a "Peanut" Tube From Frank Graver, Arvada, Colorado T WOULD like to send in my record so ■*• other fans can see they haven't all the good sets. I am using Earl A. Wright's hook-up published in Radio World, No. 39, dated December 23, 1922, but I am using a "peanut" tube instead of a regular 6-volt tube. I have had my set only a week and have heard the following stations clearly: WBAP, WDAF, KHJ, WOC, WHAI, WFAA, WMD, KZN, KSD, WOS. I have also tuned in CJCD, Winnipeg, Canada. Kindly publish a one-step amplifier to this set. If you will turn to Radio World, No. 23, dated September 2, page 18, you will find the hook-up you are seeking, in response to the query of Mr. H. S. Houston. * * * Uses W-Dll Tube Frttn Alfred L. Otmhww. m IrooUyn, N, Y, Kinffstoit At**, Brooklyn, SPEAKING of DX work, here's mine. On W-D 11 detector tube, coupler, and con- denser; aerial plus lead-in, 100 feet: Locals— WJZ, WOR, WAAM, WEAF, WHN. DX — KDKA, WWJ, WGY, WBZ, WHAZ, WOC, WDAP, WDAF, WPAC (longest reach, 1,600 miles) ; WSB, WBT. I wish the Navy Yard or Bush Terminal would get over the habit of "butting in" just when the distant announcer tells the call let- ters. I don't know how many DX stations I've lost that way. MAGNAVOX Pioneers in the Radio field IT was in 1913 that the Magna- vox electro-dynamic receiver made its first public demonstra- tion, when telephone communi- cation was held between Denver and New York — a revolutionary advance. The rise of radio broadcasting found Magna vox apparatus already perfected and in success' ful use. R-2 Magnavox Radio with 18-inch horn THIS instru- ment is in- tended for those who wish the ut- most in ampli- fying power: for large audi- ences, dance halls, etc., but requires only .6 of an am- pere for the field. Price, $85.00 R-3 Magnavox Radio with 14-inch horn SAME in principle and construc- tion throughout as Type R'2. Is ideal for use in homes, offices, amateur stations, etc. Requires one ampere field cur- rent from your filament battery. Price, $45.00 Magnavox Power Amplifier— Model C CAN be used with any "B" Bat- tery voltage which the power tube may require for best ampli- fication. AC-2-C, 2-Stage .... $80.00 AC-3-C, 3-Stage .... $110.00 The facilities and experience back of each piece of equipment bearing the Magnavox trade mark are unrivalled anywhere in the world. Magnavox products may be had of good dealers everywhere. Write to u> for Ultutrsted booklet The Magnavox Company Oakland, California New York Office : 370 Seventh Ave. Digitized by Google

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20 RADIO WORLD /WHAT parts are necessary to construct • a crystal set to receive from 30 to 60 milesT What will they cost? 2. Would an aerial 135 feet long be too large for use with this apparatus ? 3. What is the difference between crystal and bulb setst 4. Could I get a greater range with a bulb sett i 5. Crystal sets are advertised for 30 miles. Pittsburgh is 32 miles. Can I get him with a crystal self— Henry White, 451 Deer Lane St., Rochester, Pa. 1. The parts necessary are a tuning coil (2-slide or 3-slide), a pair of phones, a phone condenser, and a crystal detector. Von can use a variable condenser in the circuit to make it slightly more selective. They should not cost over $12. 2. Your antenna is quite correct. 3. This question requires more space for an answer than we can give here. The main point of difference is the extreme sensitive- ness of the bulb detector as compared with a crystal. Your range with a bulb set is from 10 to 20 times the range of a crystal set, depending on the circuit. 4. They claim that a crystal set is good for 30 miles ; but reception- on crystal sets has been covered over a range of 100 miles. 5. See book-up in this issue illustrating the article by Frederick J. Rumford. * • • Give me correct hook-up of the De Forest reflex set. Where may the necessary parts be purchased?— Henry Beck, 1098 Woodye- ress Avenue, the Bronx, New York. This particular hook-up is patented and cannot be published. We refer you to Radio World, No. 42, dated January 13, 1923. On page 4 you will find an article, Frederick J. Rumford, describing all con- structional daia on a two-tube reflex receiver- circuit. This may serve your purpose. * * * What site variable condenser should be used in the primary circuit of a radio fre- quency transformer f— Thomas Cortese. .00025 mfd. should serve the purpose. * • • Publish a hook-up, or refer me to a back number of Radio World, that contains a hook-up embodying the following apparatus: Two variometers, one variocoupler, detector phones, etc. The roters of my variometers are 2 inches in diameter and the stators are 2Vi inches m diameter, wound with 60 turns of enameled wire. The coupler has 40 turns on the primary; the secondary has 30.— C. W. Goddard, Tekoa, Washington. We refer you to Radio World No. 29, dated October 14, 1922, for the hook-up you require as well as the necessary data on its construction and operation. This is fully described therein, in an article by Mr. George W. May, "Using the Vario-coupler in a Short-wave Regenerative Set," page 4. * * » / have constructed a set using the en- closed hook-up. I get satisfactory results tuning m long distances, but there is a whistling in the phones when I remove my hand from the proximity of the panel. Thu whistling stops when I again put my hand on the panel. What is my trouble? How can I remedy it? Is the hook-up correct? Would a vorio-eupler and two variometers give me better results?— Theo. Van Dong en, 2454 Meldrum Avenue, Detroit, Mich. The trouble you are experiencing is com- mon. It is known as "body capacity." This may be remedied by shielding the back of your panel with tin or -(.r foil. Care should be taken not \« ' ' " ■ ' i n sr touch any of the instrm remove the whistling nn< :s quite correct. The distances you are making, ac- cording to your letter, indicate that you are doing very well. We advise you not to re- build your set until you have tried the shielding and noticed the difference. * * • Must I change my circuit a sketch of which is enclosed? I intend using the new W-D 11 tubes. I am at present using the U-V 200 and 201. What changes will be necessary.— L. W. Ferguson, Killorney, W. Va. You need not make any changes in the battery circuits. Your sketch is correct You will find that if you use a variable grid leak, you will get much better results with these tubes as the grid-leak capacity is some- what critical in these tubes. » • * Publish or refer me to a back number of Radio World containing a diagram of a crystal-detector set using vario-coupler, va- riable condenser, and fixed condenser. What should be the range of such a set using an aerial 75 feet long?— Ola f Peterson, 3098 Fainfield Ave., Bridgeport, Conn. See Radio World No. 37, dated Decem- ber 9. You will find a diagram on page 6, under "Efficient Crystal Sets at Small Cost," by Charles H. Plath. * e e What is the effect of putting a small con- denser across the phone terminals?— E. B. By putting a condenser across the phone terminals, sounds are made clearer due to the effect that the electrical impulses charge the condenser and the condenser discharges suddenly allowing a clearer sound in the telephones. * * * / am located 50 miles from New York City. Kindly let me know what set you con- sider the best for receiving from Pittsburgh, Kansas City, Atlanta, and other distance points. I know nothing about radio. I have heard it said that the 3-circuit receiver is better than the other and vice versa. — Wil- liam Ash, Kings Park, New York. It is impossible for us to discuss the rela- tive merits of competitive apparatus in these columns, but we will give a few of the more popular makes of instruments on the market and you can inquire as to their relative merits through friends owning sets or through the literature of the companies making same: De Forest (D-7) ; Westing- house (Senior widi amplifier) ; Radio Cor- poration (RCA and Radiola IV and V); Sleeper, Grebe, and Western Electric You mention the 3-circuit and "the other," but you do not mention what other. There are hundreds of circuits on the market Each has its own district advantage. The 3-circuit regenerative is very popular and extremely satisfactory when you understand how to manipulate it. * * * Give me the hook-up necessary for a " Calgary fan " to receive such distances as Regino, Seattle, Portland and Vancouver. Is audio- or radio-frequency necessary with the hook-up? I am using an outside aerial What apparatus is necessary?— R. H. Wil- liams, Calgary, Alberta, Canada. We refer you to an article in Radio World, No. 43, dated January 20, by Or- therus Gordon, entitled, "DX Work With a W-D 11." This article fully describes me necessary apparatus and contains as well a full-size plan for the panel layout. Very fine work has been accomplished with thu set. You will make no mistake in *M"M;"f it. You may add two steps of audio-fre- quency if you desire. » • • 1. How long will a dry ceU (154 volt) last for radio work? 2. Are the tubes advertised as the l$4-tw* tube any better than the regular 6-vaU lube? 3. Will an? dry cell be sufficient? Is • special cell manufactured? — W. H. Cook, Ogden, Iowa. 1. When used with the 1^4-voh tube, you can get approximately 100 hoars use oat of it. It is rather hard to give the exact life of such cells, as they vary; also, the heat or cold of a room affects them. 2. We cannot discuss the relative merits of the various competitive makes of tubes. 3. Any dry cell will give satisfaction. • * • Are a pair of 6000-ohm phones amy better than the regular Western Electric 2200-onm phones? Herbert & Huesgen have adver- tised N & K phones which have thai age. — William F. Grimes, 21 Ha Street, East Glouster, Massachusetts. When buying phones, it is wrong to con- sider them in terms of ohms. It is better to consider the number of ampere tarns wound on the magnet spools. You can get the desired ohmage by winding resistance wire on the spools, but the magnets will not function. The phones you refer tm are a German phone. They are slightly larger than the regular phone, due to the increased size of magnets. They are good What should be the range of a built according to the diagram prnhhshed in Radio World No. 14, dated July I, 1922, page 13. / am using molded Tuska vario- meters and couplers? What aerial should I use with the above set? — Fred A. Kurtee- born, Jr., St. Louis. There is no specified range to any re- ceiver. The range depends partly on local conditions and partly on the strength of the transmitter. Sets using the hook-up you mention have been successful in receiving over 1,500 miles. You should have no trou- ble in doing similar work with one addi- tional stage of audio-frequency amplifica- tion. A one-wire aerial from 100 to 150 feet long is sufficient. Try tat to tone In Europe. A hard Job. (Cartoon by Marcus In The Timet," New York.) Complete Your File mi RADIO WORLD Carlos of RaaB. World Mm. 1 SZ Weeks for t*M If you did not get a copy of Radio World No. 1, scad us $6.00 and we will send yon this paper for one year, aad start it with our first issue, which win be mailed yon as soon as possible after re- ceipt of order. Digitized by Google

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RADIO WORLD 21 Fifty Millions May Hear at Once, by Radio A RECENT achievement in telephony in- dicates that it may soon be possible to radio a message into the ears of 50,000,000 Americans at the same time, says "The World," New York. A. H. Griswold, Assistant Vice-President of the American Telephone and Telegraph, was an invited guest at the annual dinner of the Massachusetts Bankers' Association at the Coply-Plaza Hotel in Boston. Mr. Griswold connected by wire a studio at No. 24 Walker Street. New York, where several artists were performing a radio program for the local radio district. The New York program was played in Boston through the apparatus of a depart- ment store. Then, by wire, it was conducted to the banquet hall of the Copley-Plaza. Mr. Griswold put on a loud speaker and the New York program was transmitted to the thou- sand or more diners with the utmost dis- tinctness. It was the first time that a . radio program in one district had been given simultaneously in another district. The New York station was WEAF, and that in Boston WNAC. Telephone officials and scientists were en- thusiastic over the prospect opened by the simultaneous broadcasting of a program from two radio stations more than 200 miles apart. "Get the picture." said one. "If it is possible and practicable to transmit the speaking or singing voice from New York to Boston at a single point, why cannot the same speaking voice be transmitted to thou- sands of points at the same time? "There are thirteen millions of telephones in America — more, of • course, than in any country in the world. It would take a lot of money — millions of dollars — to transmit a program given in one district to, say, forty districts. But if the necessary connections were made, as they were from Boston to New York, with forty other centers up and down the continent from the same point, the entire country could be supplied with the radio program coming from a single studio. "That would mean that at least fifty million persons in America could hear the same song or the same speech at the same time." • » • When Sick at Sea A DH-Ma«Be» lUatognua Briags Pre- faaaioaaJ Hatp from NtwMt i««rc« NEXT to SOS messages. DH-Medice radiograms are given right of way at sea. DH-Medice signifies advice radioed by medical officers to ships requesting assist- ance in a professional way for ill or in- jured men. The United States Public Health Service announced last February, that arrangements had been made with the Radio Corporation of America, whereby the Public Health Service would furnish free medical advice to ships at sea through coastal station of the Corporation at Chat- ham and Siasconset. Massachusetts ; Bush Terminal, New York City; Cape May. New Jersey, and San Francisco. It was expected that request for advice would, in most in- stances, be made by vessels not carrying physicians, although consultations mipht be requested in some instances by ships' doc- tors. An officer of the Public Health Service, on receipt of a request for medical advice, furnishes promptly whatever advice seems Radio World, 52 braes, $f.M. Subscribe direct or through your news dealer. $6.00 a year, $3.00 six months, $150 three months. Radio World, 1493 Broadway, N. Y. C indicated, couched in language intelligible to a layman. While the Panama Canal was not included in the original scheme, several requests for medical advice have been received there from ships at sea, which have been given prompt attention. The United Fruit Company has now es- tablished a similar system of free medical advice in the Caribbean and the Gulf of Mexico. A message from a ship's captain to any of the company's radio stations in Cen- tral America or Colombia giving the details of a case of illness or accident on his vessel. will be answered by the company's physicians without charge. The United Fruit Company requires that radiograms requesting medical advice be signed by the captain of the ship and state briefly, but clearly, the symptoms of the per- son afflicted. Such radiograms should be addressed "Unifruitco" and may be sent to any of the following United Fruit Company hospitals : Santa Marts, Colombia; Port Li moo, Costa Rico ; Almirante. Panama ; Tela, Hon- duras; Puerto Castilla. Honduras, and Puerto Barrios. Guatemala. 11 YEARS ON THE SAME SPOT LOOK AT OCK PRICBt DMnml U Sa. ..IU.lt VMM «mtar .. 4.SS B. C A. 711 BARGAINS EVERY DAY §E . » w- •»■» ■■ ... isa*"- «•» *mmm . S.SI ■«■'■■ i SS n. 41 Kim ' ' - AU «* rHiiri prte—. Opt* MU 10 fcloc* mrnmry at***. CI IK fDr A M Monty irdmr ar «rt«u« aftaw* mull mo dUlNDLArl SUNBEAM ELECTRIC CO. 71 THIRD AYE. (BET. Uta aaa Utk STRUTS) T* HBW TOW P I / WALCON Radio Frequency Transformers mm a I up |iflm TR UVT TOO CAM BUT WALTON •*MH*4 9mm wttm ST.*. 1 1 immm. Tm aiiaaaS aaa*— «MS mmrm Pit**, $4jSfJ. ytm pmj DmaUrt aaa* fmbmmrt : Wtit» fmr mmr atlraaHai aalai THE RADIO CENTRE. I W- Brood way, h.Y, N.T. Attention ! Fans and Amateurs ! Hava yaa Mk ymm mwn An jmm aiailMMki wUk mmf par ticoaax aaak aaF An ymm laaere An r*a •»*■• «W tiv. war* m> Whm mm " «r _ ml mmw mmm mat mm rim ktn M — «». m m ymm mt at 4mmm aartMag *• aaunaJ. \m% la* RADIO WORLD. 1495 Broadway. Now York City. N. Y. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Please send me RADIO WORLD for. please find enclosed % SUBSCRIPTION RATES: Single Copy • Three Month* J * Sim Montht 3 00 One Y'»r (» Iatuea) S-W Add 1100 • Year tor Forriga Pottage. 50c for Canadian Pu«( »«e- 1493 Broadway, New York City months, for tsaWA Digitized by Google

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $15000 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 How Radio Figures in Big Business As Told by the Annual Balance Sheet of the Radio Corporation of America Coming Events Plant and Equipment : Comprising High-Power Stations in Operation with the necessary equip- ment thereto, together with ship stations and sundry machinery, tools and furniture $12,702,086.84 Patents, Patent Rights, Contracts, Goodwill, etc 16,584,845.50 Stocks of Subsidiary and Associated Companies 598,000.00 Current Assets: Cash on Hand and at Call $550,455.74 Accounts Receivable 2,967,497.66 Merchandise Inventories 895,232.80 Investments at Cost (Market Value December 31, 1921. $494,039.90) 497,737.42 . 4,910,923.62 Deferred Charges : Including Organization Expenses and part of the cost of re-establish- ment of the transoceanic business 916,228.58 $35,712,084.54 Liabilities and Capital Capital Stock * 3,955,974 shares 7% Preferred, $5 par $19,779,870.00 5732,000 shares Common (no par value) 12,039,607.88 $31,819,477.88 Current Liabilities «... 954,471.07 Deferred Liability 620,000.00 Reserves : For Depreciation of Patents— Balance $964,284.12 Add: Amount Transferred from 1921 Earnings 426,799.59 $1,391,083.71 For Depreciation and Obsolescence of Plant 818,329.42 Other Reserves 106,722.46 2,318,135.59 $35,712,084.54 Gross Income from Operations : From Transoceanic Communications $2,138,625.80 Gross Sales 1,468,919.95 From Marine Service 553,298.71 $4,160,84452 Deduct- General Operating and Administration Expenses, Depreciation of Plant and Cost of Sales 3,762^31.48 $398,613j04 Other Income 28,18655 Balance Applied Against Amortization of Patents $426,79959 Business Always Good Somewhere BUSINESS," says Roger W. Babson, the eminent economist, in "Forbes Maga- zine," New York, "is always good some- where. The business cycle is continually in progress, but it travels gradually across the country north and south or east and west. The sun rises and sets once in every twenty- four hours, but it rises at a different time in the East than in the West. The sun of pros- perity is always shining somewhere. The student of fundamental conditions will al- ways know where that bright spot is and there he will be selling his wares. "The selling of goods is very much bound up with the tastes, customs, and fashions of the people. These, likewise, are changing constantly in accordance with definite eco- nomic laws. We criticize women as being the slaves of taste, custom and fashion, but can they help it? If they cannot help it, it is due to the fact that taste, custom, and fashion are governed by fundamental laws. If this is so, it is entirely possible to fore- cast the changes." maOtng hill information. PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September. 1922, to May, 1923. SECOND DISTRICT RADIO CONVENTION. Hotel Pennsylvania, New York City, March 1. 2, and 3, 1923. FIRST UNIVERSAL EXPOSITION OF IN- VENTIONS AND PATENTS, Grand Central Pal- ace, New York City, February 17 to 22, Inclaafva, 1923. SOUTH JERSEY'S FIRST RADIO- ELEC- TRICAL SHOW, Third Regiment Armory, Cam- len, N. J., February 5 to 10, inclusive. New Firms and Corpora- tions (The Arms and corporations mentioned in these columns can be reached by communi- cating with the attorneys, whose addresses ire given whenever possible.) Capital lac Paceant Electric Co., Manhattan, $50,000 to $150,000. Redhead Mfg. Co., Manhattan, make tools, $20,000; H. H. Silverman, B. Rosen. (Attorney, M. E. Levin, 299 Broadway. New York.) Stenzel Mica Corp., Wilmington, Delaware, mining, $250,000. (Corporation Service Co.) Radio Co. of Philadelphia, purchasing agents, $300,000. (Corporation Guarantee and Trust Co.) New Representative Multiple Storage Battery Corp., Delaware; new representative, N. D. Sturgess, Jamaica. Claims for the Vac Shield ONE of the latest radio devices on the market was developed by the Orange Research Laboratories, East Orange, New Jersey. It is known as the Vac-Shield. This is the invention of Ed. H. Lerchen, well known in the electrical industry. The purpose of this nonmagnetic shield is to prevent interstage coupling and elec- trostatic effects between detector and amplifying tubes, which overcomes stray capacities which cause unnecessary noises and which make it so difficult to tune in distant stations. The Vac- Shield also acts as a guard against breakage of the tube. It is particularly valuable where radio- frequency is used or wherever the distance be- tween the vacuum tubes is less than 8 inches. They are so constructed as to be readily attached to the tubes in a few minutes without trouble, and are made to fit all standard makes of vacuum tubes. On account of their efficiency they are becoming very popular among radio fans. A New Transformer AN audio-frequency transformer of unusual design has been placed on the market by the Radio Supply Company, Hornell, New York. It is of the closed-core type, and is slso shielded. Due to a unique winding a large core was found to be unnecessary. It is especislly recommended to radio enthusiasts living great distances from broadcasting stations. Three stages of audio- amplification may be used with practical results. Digitized by Google

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RADIO WORLD 23 License to Broadcast Issued Official Document Permitting Radio Stations to Broad- cast Copyrighted Music Issued — Fee to Be Yearly and Payable in Advance THE efforts of the American Society of Composers, Authors and Publishers to collect license fees from radio broadcasting stations seems to be taking definite shape. The official license agreements whereby the radio interests are given permission to broadcast the coyprighted music owned by members of the society have been issued. A stipulated sum as an annual license fee is payable in advance. This amount varies upwards from a minimum of $5.00. As a matter of fact, it is the intention of the society to issue the license, not so much for the fee, but for fees that it will be necessary to collect in the future when radio broadcasting has reached a stage when it will seriously affect the society's members' revenue from other sources. The contracts now being made are more in the nature of a safeguard of the rights of the composer and others for a later period. The "License to Broadcast" has been drawn up as simple and as concise as pos- sible. The text of the agreement being entered into between the American Society of Composers, Authors and Publishers follows in full: LICENSE TO BROADCAST No. AGREEMENT made this day of 1923, between the AMERICAN SOCIETY OF COM- POSERS, AUTHORS AND PUB- LISHERS, hereinafter designated as the "Society," and hereinafter designated as the "Licensee," as follows: 1. The Society grants to the "Licensee" the license to broadcast by radio (as here- inafter limited in Article 3) the musical numbers in the repertory of the Society from the Licensees broadcasting station, located at , City of State of 2. The Licensee accepts such license, and agrees to pay to the Society the sum of $ annually, payable in advance. 3. This license is not transferable; is strictly limited to broadcasting from the station hereinabove mentioned; and is further strictly limited to broadcasting non- dramatic renditions, vocally and/or mstru- mentally (with an organ, phonograph, piano, orchestra or band). 4. The Licensee agrees to make the following announcement upon the com- mencement of each program in which musi- cal numbers from the repertory of the Society are broadcasted: "By special arrangement with the Ameri- can Society of Composers, Authors and Publishers musical numbers contained in the Society's repertory will be included in this program." 5. If required by the Society the Licensee agrees to furnish to it (upon forms to be supplied) a list of the musical numbers contained in the Society's reper- tory used in each program. 6. In case the Licensee shall make default in the payment of the annual license fee, or shall violate any of the other terms or conditions of this license, the Society mar, at any time after such default or viola- tion, without previous notice to the Licensee, terminate this agreement; and, upon such termination, this license and the rights and privileges herein granted to the Licensee shall immediately cease and terminate. 7. The Society reserves the right, at any time, to revoke the privilege of the Licensee to broadcast by radio any of the numbers in its repertory, and upon such revocation the Licensee shall have the right to termi- nate this agreement forthwith, by written notice, mailed to the Society at its usual place of business; and, in the event of such termination, a pro rata amount of the license fee, paid in advance, shall be re- funded to the Licensee. 8. The parties hereto hereby agree that this contract shall be deemed to be, and shall be, extended and renewed from year to_ year unless either party, on or before thirty days next preceding the termination of any year, shall give notice to the other of intention to cancel the same, such notice to be given in writing by Registered Mail. IN WITNESS WHEREOF, this agree- ment has been duly subscribed and sealed by the Society and Licensee. American 'Society of Composers, Authors and Publishers. By .-. By " " ." ." ." .' ." " ." ." ." * .' ." ." ." * ." ." .* ." .■""."."( LI " Si) .Who Is to Pay for Broad- casting From an Address by General James G. Harbord, President of the Radio Cor- el ration of America, Before the Illinois Manufacturers' Asso- ciation TO-DAY we have newspapers, auto- mobile schools, electrical manufac- turing companies, and chiropractic schools doing broadcasting. Can these various agencies continue when it costs from $25,000 to $50,00 a year to put on continuously a generally satisfactory program ? If not, who is to do the broad- casting? Theoretically, the 600 stations scattered throughout this broad country are operating on two wave lengths, one of 360 meters and the other of 400 meters. The result is man-made interference and confusion. One of two things happen — either good programmes suffer from this Interference, or stations capable of serv- ing many thousands are asked to give up time on a specific wave length to a smaller station, which can at best serve only small communities and a limited number of people with inadequate pro- grammes. It is popularly believed that radio com- munications being carried on through the air may be operated to an unlimited ex- tent. That, unfortunately, is not true. The spaces in what scientists call the ether, through which communications may be carried on, are very limited. They are like a definite number of paths, or a city street upon which only so many soldiers can march shoulder to shoulder. The government can assign additional wave lengths, but there are not available in the ether 600 wave lengths which can be allocated to telephone broadcasting. Who is going to pay for broadcasting? I cannot answer that question, but if we have a national service, organized and administered with the ideal 'the greatest good to the greatest number" as the watchword, it will no doubt be possible to devise some means of obtaining com- pensation for the cost of service either from distributors of apparatus, suitable contribution from listeners, or by the public- spirited endowment of a Carnegie or a Rockefeller. Fifty-two ism as for $6jM. Sab. De- partment, Radio World, 1493 Broadway, M. T. C Whatever Your Question Be it the pronunciation of Bolshe- vik! or soviet, the spelling of a puz- zling word — the meaning of blig-hty, fourth arm, etc., this Supreme Authority— WEBSTER'S NEW INTERNATIONAL DICTIONARY contains an accurate, final answer. 400,000 Words. 2700 Pages. 6000 Illustrations. Regular and India-Paper Editions. G. & C. MERRIAM CO. Springfimld, Man. Write for specimen pages, prices, etc., and FREE Pocket Maps ii you name Radio World. THE ONLY GENUINE AND GUARANTEED "All Wave" Coupler TRADE MARK «afc TRADE MARK FLAT AMD BANK WOUND Wave Length. 150 to 3,000 Meters Eliminates th0 of Varlomaters, Yartoeouplars and Loading OIK, Inu- much u It parformi In ana miwt unit 3s function! of SB <* thaoo dorloas combined. Forth* N wIh ££Tx£t'SZ,.?^Zr?* S&A L2£ 2SSC U™s^ R«^s Attained- ^^^V^SSSSWR Semite of Imitations— ytLS^JSSteSSAiZl ff^ir?-;^ trad.™*. "AU W.,a." on ^ g£? afc\£ 5x^X^2^ f^'bof %Q Clf\ 8Ix '',n' Hook-ups sent upon receipt of lea. »\f\f stamp., or Fret with eavh "Alt Wmtm" Cony taw GUARANTEED WITH AN ABSOLUTE MONEY-BACK GUARANTEE THOUSANDS OF SATISFIED USERS Capitol Phonolicr Corporation Pfttmtt 6nt*t*a1 and PtndlM OKy Digitized by Google

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24 RADIO WORLD Claims the "Radio Golf" Record Retort H. Anthony Makes a Grand Total of MJM Miles la 14 Hours aad a Mlautss OVER 3,576 miles an hour is the radio distance covered by Robert H. An- thony, 18 Cleveland Road, Needham, Massachusetts. This speed was maintained December 30 and 31, over a period of 6 hours and 20 minutes. Among the cities "visited by radio" were San Francisco and Long Beach, California; Roswell, New Mexico ; Colorado Springs, Colorado ; Dallas and Fort Worth, Texas ; Havana, Cuba ; not to mention such nearby communities as Mil- waukee, Chicago, St. Louis, Atlanta and Birmingham. The broadcasting of all these cities and many more, totalling 45 in all, was received during 14 hours and 20 minutes operating time on the evenings of December 24, 25 and 30, and the early morning of December 31. The total number of miles covered dur- ing this time was 39.345, which establishes Mr. Anthony's claim to' being a radio golfist of high rank. Higher radio golf-cards may have been turned in, but this is believed a record, con- sidering the time of play. "Radio Golf" is a new game invented by Frank Jones, of Tuinucu, Cuba. It is a gentleman's game. Everyone keeps his own score. A record is ' kept of all broadcasting stations heard. A broadcasting station may be computed only once. The mileage between the broadcasting station and the radio-receiving set is com- puted from the map and the various distances added up. Mr. Anthony is New England manager for R. Thomas Sons Co. The equipment Actual Size The HOYT Peephole Ammeter or Voltmeter To protect your Tube* $3.00 // your Dealer or Jobber cannot supply you write BURTON-ROGERS CO. 78 Beylaton Street Bwtn 17, Man. SPECIAL STOCK REDUCING SALE LIMITED SUPPLY All New Merchandise Terms C. O. D. — First Come First Served. Immediate Shipment. Myers Vacuum Tubes f 3.85 each net Myers Adapters $1.20 each net Myers Audio Frequency Choke Colls S«.SS each net Myem Kadlo Frequency Choke Colls S3.3B each net Myers Receptacles $0.70 each net Mica Fixed Condensers .25 Mfd »4.05 each net Mica Fixed Condensers 2.0 Mfd $1.70 each net Hartman Radio Company MANSFIELD, OHIO References — Any bank or banker in Mansfield, Ohio with which he made this phenomenal record was a standard Amrad-radio-f requency re- ceiver employing one stage of radio-fre- quency and two stages of audio- frequency amplification. San Francisco was heard clearly through a loud-speaking horn. Below is Mr. Anthony's score card: December 24. 3 hours' play Station " Miles WAAK— Milwaukee 920 WIP— Philadelphia 290 WOC— Davenpon. Ia 1035 WGY— Schenectady 87 WRR — Dallas 1610 WDAC— Springfield, 111 1006 WHK— Cleveland 575 WHB— Kansas City, Mo 1294 VVQAA— Parkersburg, Pa 317 WJZ— Newark 201 WHD— Morgantown, W. Va 544 WAH— Eldorado, Kansas 1438 Local stations 15 Total 9332 December 25. 5 hours' play. WJZ— Newark 201 KYW— Chicago 892 WHD— Morgantown 544 WJAX— Cleveland 575 WGY— Schenec.ady 87 WWJ— Detroit 633 CFCF— Montreal 259 WBZ— Springfield, Mass 66 KSD— St. Louis 1092 WOO— Philadelphia 290 WYJ— Los Angeles 2712 Local stations 10 Total 7361 December 30-31. 6 hours, 20 minutes' Play WEAF— New York City 201 WGM— Atlanta 978 WIP— Philadelphia 290 KDKA— Pittsburgh 489 WFI— Philadelphia 290 PWX— Havana 1571 WAAK— Milwaukee 92r KSD— St. Louis 1064 WRR— Dallas 1610 WKM— Memphis 1179 WPA— Fort Worth, Texas 1639 WDAC— Chicago 892 KHD— Colorado Springs 1869 WMAF— South Dartmouth 64 KNJ— Roswell, New Mexico 1984 KSS— Long Beach, Calif 2703 WSB— Atlanta 978 KDN— San Francisco 2818 WSY— Birmingham, Ala 1093 Local stations 20 Total 22652 Grand total : 39,345 miles in 14 hours and 20 minutes. Badly Needed A RECEIVER capable «f traaisf rifht through the local broadcaster and bringing In DX on the same wave he Is em. A tube which will not break if beunced on a hard head er floor. A filament which will not calmly Belt when 6 to M volts are shoved through it, vet which will operate en 1V4. A questianaaire of all the foolish questions asked about radio. Copper wire that can be stretched. Buy IN feet and use it for 5N feet by simply stretching it like rubber! A squelcher for the spark box supposed to bo on ZOO meters, but who is hoard from ISO to UN meters. A wave filter that will Altar. A radio tube that sails for 2S cents. A "log book" which will keep Itself. Subscribe direct er threetgb year news dealer. $€.00 a year, $3.00 six months, $1.50 three months. Radio World, 1493 Broadway, N. Y. C 1 8.75 WMtlaghouM Stores. "B" Bat- teries I 4.09 18.00 Weitiegkeuu 80-80 Amp. Bat- teries 12.00 18.80 Haenekaner De Luxe Medel.... IS.00 7.00 All- Meter Triple Beak Weusd Ceupler $.09 15.00 Crystal Set Ceamlete $.09 4.00 Finest 43 Plate Coodeswre 1. 1 J Cash with order. RADIO ENGINEERING CO. 2 West »8th St-eet New York Cjty FRESHMAN Variable Grid Leak and Micon Condenser Combined Clariut-» Mfiml,, l.ii>.r„ In.. nt Cur- rent, lm-reai.es Ilmtery Life, Eliminates Hissing Unbroken range — zero to 5 Megohms: all Intermediate points. Fixed capacity, .00026 It P. Only $1.00 At your dealer's — otherwise direct on receipt of purchase price. Manufactured by CHAS. FRESHMAN COMPANY,Inc. 97 Beekman Street New York City Why are so Public Libraries Y. M. C. A's. K. of Co. Y. M. H. A's. Army Posts Social Clubs Industrial Libraries Aad others in this subscription group ordering subscriptions for Radio World from all parts of the U. S., Canada and foreign countries? THE REASON Because so many Of their members Are interested in Radio That they want to read RADIO WORLD every seven days. Ask the Association or Club To which you belong To subscribe for RADIO WORLD Tin Great IUustrattd Ntitnml Weekly (10.00 a Year. 92 Namfeers tS.OO Six Montki: 11.90 Tares Meats.) RADIO WORLD 14t3 Broadway Now York City Radio World, 52 ia Subscribe direct or tbrosjjjh newsdealer. $6.00 a year, 33J0 six months, $1.59 three months. Radio World, 1 Digitizer! hv 483 B'°"w' * Y. C

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RADIO WORLD 25 IMPROVED RE1NARTZ CIRCUIT sty blghli Improved elreu.lt brings Is all Import*** ■ Mm w bath eoeeie and the Union banter wltboat i autartlon or other ntlM. W* duel »o iMwtt treat Atlanta raeelved on one tend Ma emit. Mid ana at tbaaa supersensitive set* from a_ tod epeelncatloce. Pries 50a ar with a partaal and eoae- Nau doable wvsnd splderweb oaU ft.** br malt ■a other wlndlim need. ■bat* ef m> set en a flaaa panel with every ardar. ffrerythln* elearr/ shown. Cheap and soar ta balid. ■err u operate. t. A. TWITCH KLU 1*23 Wester* A».. Mlaaipellt,Miaa. Larfreehlrt manufacturer wants ag-enta to eell complete line of shirts, pajamas. I and nltrtitfttilrts direct to wearer. Ad- \ Tertlsed brand-exclusive patterns-H?asy /to sell. No experience or capital re- quired. Entirely new proposition. VNOVQ NOTE THE INSULATE!) BINDING POSTS AND 7lN. WIRE CONNECTOR NOVO M'F'G CO '42,,W^? ST' ■ ■ • - 53I..SO DEARBORN ST. new yqrk Chicago GIT HENS TKUTONE RADIO HORN— LOUD SPEAKER First one to sell on ten day trial Money back Guarantee i beat on the sea re. Retail Price RttJN Inelode*. Lond Speaker Truloee naa bear pn to uieiu It haa a altar, true ton- fan shoold tr» Truton. and oomparo It with athera. H TOD don't and Trutone the nest, jour osooej wlU aa refunded It Is sold on a ten-da* trial mane; -bank guarantee If not earrted OT vour dealer write aa. Diatriovutora and Dealer*, write/ AUTO PARTS MFG. CO. 1*15 Trnrnhly Ave. IretroW, Mleh A B C of Aviation Br CAPT. V. W. PAOB. Tbls book deaerlbea the basis prlndplaa af aviation, tela* how a balloon ar dtrllttbla la made and why It Moats In the aJt. Deaerlbea how an airplane files. It shows In de- tail the different parts of an airplane, what thai are and what the* do Keawlbea all type* of air- plane* and how the* differ In eonstruetlon; aa well aa detailing, the advantages and disadvantage* of different tvpee af aircraft. It Include, a aom- plete dlrtlonar* of svlaiion terms and clear draw- Intca of leading alrplance The reader will And simple Instruct Inna for unpacking, netting up and rigging airplanes. A full tleacrlptim of airplane sontrol principle* Is given and methods of flying are discussed at length. This boa* answers etery question one can aak about modern aircraft, their construction snd opera- tion. 1T5 pane*. ISO eiwclally made Illustrations with 7 nlstes. Prloa. $2.60 THE COLUMBIA PRINT l*n Broadway, New York City We Want Your Name a* • pastel card. We would Ilk* te eet the mm* af avsry RADIO WORLD reader, as we ax sect ta send sut a special message to sur readers. It will lataraat yen. Ca sura te Mad us your name an a postal sard, and address it SIFT DEPT.. RADIO WORLD. 14*3 Broadway. N. V. RADIO WORLD TaTLaTPHONa, BIT ANT 4T*S FtTBXJBllKD atVaWT WXDNbWPAY (Dated eUTCHDAY OF 8 A 111 Willi ITtOM PUBLICATION OPTICR 14*3 BBOADWAT, NaTW YORK. H, T. BT HMNKESST RADIO PrBIJCATTOJtn COBPO RATION ROLAND BUBVKE BBNNB88T. PTBeadaet and Editor M. B. Ht.VNRSeTT. Vice- Preal dent l-RED & CLAHK, Beeratary and Manager 14*3 BROADWAY. NEW YOBK. N. Y. ASSOCIATE EDITORS Robert Mackay Robert L. Dougherty SUBSCRIPTION RATES IWtaeai eon la a oapy. It (0 a year. IS.** fas alx assert he, 11.30 fee three month*. Add $1.00 a year extra for foreign postage. Canada 50 cents. Receipt by new aabacrlber* of the Brat sec* of RADIO WORLD Bulled to them aflat sending la their ardae. ta etrteeaatle srkaowladgwsat af their subaertptlon order: ADVERTISING RATES One page: One time $130.00. Halt. Quarter. Third and Two- third* proportionate rata*. One Inch, ana Ums — $(.**. Par aaat $».4*. On faur aanaeeutlv* lasue*. 1*** dteeoant On thirteen eonaecutlte issues. 1$% dial Caver and pnCerrad-poaltlaa rata* asada an application. Tenaa. $• day* Net. 3% 1* day*. CLASSIFIED ADVERTISEMENTS Five cents per word. Minimum, 10 words. Dla- eaont af 10% on 4 eonaecutlte laauaa — 19% ea thirteen aanaeautiva leausa. Caab wtlh order. Entered aa seeand -class metter, atarah 33. 1*33, at lb* P*n Office at New York. New York. Baxter she art of March 3. 13T*. IMPORTANT NOTICE Waal* every possible car* te take* te state correctly man era at fact and eptnlea la Issaaltsl aad ganaral wrttlacs aavarlag the radto Sold, and every Una printed k) gene aver with a scrape lews regard far aha facta, the puhnshir dteelalaaa any res ponat bill tr far ststeessata regartnag najsatJaa* af patents, petarlty of tie law. the proper working ant af technical Peebles* . or ether matters that amy bo printed la good faith aad a* legareaatiaa faralehed hy Phone supposed ta be t rant worthy. nsont ta aaada la gsad faith and u save la matters PATENT Club News THE Amateur Operators' Club of Bre- merton, Washington, announces the fol- lowing officers: Walter R. Wood (7ABV) chief operator, president; Eugene Bailey (7 ABW), first operator; Ed. Flodquist (7NG), second operator and traffic manager, mm * The Lorain Radio Association, Lorain, Ohio, has elected the following officers: Charles S. Smith, president; O. S. Ellison, vice-president; R. R. Ward, secretary; P. J. Stephen, treasurer. * * * The Wireless Society of London has changed its name to the Radio Society of Great Britain. Look Out for Radio Stock Fakirs WARNINGS are being sent out again regarding offerings of bogus radio company stock. One concern uses a name so similar to one of the successful com- panies that people are buying its stock be- lieving they are investing in the older cor- poration. Slower Than Radio A DELIVERY wagon was seen at 43rd Street and 8th Avenue, New York City bearing the following sign: "RADIO MARKET. We deliver your purchases anywhere in New York, same day as bought. Try us." This statement seems a little far-fetched when compared to "radio. If the butcher had stated that he delivers at a rate of 186.000 orders per second, he might have some claim to his boast Call wr Writ* FREE ADVICEl SPECIAL OFFER For • limited time oxaly. BA-M. .fam Grebe CB-» I DA-3 . . . M Grebe HORK Prises F.B.B. Red Bank. N. J. A. V. GREGORY 4t Broad Street Red Bank, J». Build Your Own Set 15c -THE RADIO CONSTRUCTOR"* A book showing twelve arize kanak- as* and loll detail* of hurt bow *a bttiid yowx own aat *avi*g keif it* I KCWMU I 00.. 74 MY IT., NEW YOU RADIO MAILING LISTS a* U. a. a, ...r ear Mat 13.00 aavarla* U. par list l*.*0 Mr list 4.M aaamkla aem- ear Hat, 4.M Maaaoara af par M 7.5* Enclsss ether lists TRADE CIRCULAR ADDRESSING CO. ISO W. ADAMS STREET CHICAHw. ILL. 12.400 Radls Dealers. States 1.614 Radls Mfrs. States 1.797 Ragle Si 360 Radio "static 267 Mln. who make a piste Radio 8c 26.000 Radio Amateurs Radls Stations Ask fsr price lists fsr Canada THETOOODMAN i Tke NirtUnt Skort Wawa Toaar am the Maarwat Only HM A PI* am 1 aV. Semd tar aeaaaaakaat L. W. GOODMAN DREXEL BILL, PA. Daaaar . N err istew a. Ps-. wrttaa: Lists* la* la l as a* 1 1» with my BOODalAN. beard a Bat**, "We are aew It mile* sat from tea Fraaelaae.** Than OCNVER aaava la and an*k tke ski*. To the Man with an Idea I offer * compreherj»i»e, experi- enced, efficient service tor his prompt, legal protection, and the development of hi* Send sketch or model and tton, for advice aa to through prior United State* patent*, etc. Preliminary advice gladly furniahed without charge. My experience and familiarity with varioua arts frequently enable me to accurttely advise client* as to probable patentability go to any expense. Booklet ef valuable Informs for properly dlarlnalng roar Idea, free en request Write today. RICHARD B.OWEN, Patent Lawy. 32 Owes Bulldlaa. Ws.hlaatea. D. C. 2276 P Woelworth Bid*.. Now York Oltv Fifty-two issues for $6.00. partment, Radio World, 14 N. Y. Qzed by Sub. De- roadway,

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26 RADIO WORLD Here's Your Radio Library! Useful Technical Articles Published in Former Issues of Radio World APRIL 1. A 600-MUe Radiophone Employing a 5- Watt Tube, by Frank A. Hahnal. "Tall Me. Please, How Will Thla Bet Re- oetve?" by B. L Bragdon- Short Cats In Reeelver-Clreutt Design, by O. G. Roos* Making a Short -War* Regenerator, by Fred. Chae. Bhlert APRIL 8. Do Ton Know Tour ReeelTtag Bqnlprnoat, by Jamea D. Gordon. Why a Cryetal If Called a Rectifier, by Wal- ter Bmmett. Is Radlotelephony Dependable? by O. O. Root. Mounting Crystals ■ — - • - - * Bragdon. In Tour Deteotor, by B. L Storage Batteries tor Radio, by Fred. Okas, ■alert. APRIL 15. First Principles of Electricity as Applied to Radio, by John P. Miles. Tour Storage Battery, by B. L. Bragdon. What Makes Radio Possible, by Bdward Lta- Oround Connection as Vital as Antenna, by Fred. Chas. Bblert APRIL 29. / Valuable Polo ten on Aerial Construction, by Bdward Linwood. What la Meant by Tuning, by B. L Bragdon. Radio-Frequency Amplification and Regene- ration, by Frank Armstrong. Honey-Comb Colls and Condensers, by Bd- ward Lin wood. Charging the Storage Battery, by B. L Bragdon. How to Construct the Varioooupler, by Fred- erick J. Romford. MAT ft. The Advantages of Radio Frequency, by Harold 8. Potter. How to Construct Protect and Operate a Storage Battery, by George W. May. The Beginner's Catechism, by Bdward Lin- wood. Tuning and What Is Meant by It, by Fred. Chae. Rhlert. New Frequency Amplifier Brings Faintest Waves in Strong, by O. W. May. MAT 18. My Practical V. T. Deteotor and Two Stage Amplifier, by Frederick J. Romford. The Principles of Radlotelegraphy, by Wal- ter J. Howell. The Reason for the Loop Aerial, by George W. May. Tuning and What Is Meant By It, by B. L Bragdon. The Bi Beginner's Csteohlsm. by Bdward Un- MAT 20. The Design of an Amateur Reeetrtng Set. by C. White. The B Battery and the Plata Current, by George W. May. Radio Terms at a Glanoe, by Fred. Ohas. Bhlert. The Beglnner'e Catechism, by Bdward tan- Fire Undewrltero' Rules, by Fred. Chae. Bhlert. MAT ST. The Beglnner'e Cateehlsm, by Bdward Lin- How to stake Tour Own Condenser, by W. May. Tuning as Applied to Telegraphy, by Walter J. Howell. Why the Condenser Doesn't Condense, by B. L. Bragdon. Making Signals Loader with Two-Stage Am- pllfler, by George W. May. JUNE 8. The Cost of a SIngle-Olreult Reoelver, by Howell W. Miller. The Beginner's Catechism, by Bdward Lin- How to Compute and Build a Fixed Conden- ser, by B. L Bragdon. Design for an Amateur's Receiving Set, by C. White. tery, tmple . by Simple Method of Recharging a Storage Bat- John Grayson. JTJNB 10. Radio Reoelver for Short Waves, by George W. May. How to Filter Atmoepheric Conditions, by C. White. The Messenger Boys of Broadcasting, by B. L Bragdon* Are Ton a Member of the N. O. D. C.T by B. L. Bragdon. The Beginner's Catechism, by Bdward tin- How to Construct One- and Two-Slide Tuning Colls, by George W. May. JTJNB 17. The Vaouum Bulb's Start In Life, by C. White. How to Select the Right Bet, by B. L. Brag- don. The Beginner's Catechism, by Bdward Lin- wood. Test of Induetanoe Colls, by Fred. Chae. Bhlert. Short Wavee from a Simple Receiver, by Stanley Bryant. JTJNB 94. . . How to Make Tour Radio Cabinets, by W. 8. Standi ford. _^ _ How the Cryetal Detector Is Deed to the Best Advantage, by C. J. Williams. How to Construct ' a Long-Wave Regenera- tive Reoelver, by George W. May- Tested Invention of Major Armstrong AmpU- See Set 100,000 Times, by John Kent. Repairing Cracks In Hard-Rubber Storage Battery Jars, by W. 8. Standlford. The Beginner's Catechism, by Bdward Lin- wood. JULY 1. Novel Unit-Detector and Amplifier, by Fred- erick J. Rumford. Why You Moat Use a Condenser, by C. J. Williams. How Wave Lengths Travel, by Fred. Chae. Bhlert. Radio World's Revised Dictionary, by Fred. Chas. Bhlert The Beginner's Catechism, by Bdward Lin- Use of the Vacuum Tubs Detector, by George W. May. JULY 8. Radio's Place In the Phenomena of Nature, by B. Li. Bragdon. The Function of the Loose Coupler, by Charles H. Plath. Armstrong's Superregeneratlve Amplifier Fully Explained, by John Kent. Operating a Transatlantic Station, by Fred. Chas. Bhlert. The Beginner's Catechism, by Bdward Lin- Reducing Strays and Static, by Fred. Chae. Bhlert JULY IS. Assembling a Deteotor and Two-Stage Ampli- fier, by H. 8. Stanford. Combined Radio and Audio Frequency AasPil- floatlon, by C. White. . The Beglnner'e Cateehlsm, by Bdward Lin- Lamp- Socket Aerials, by Locating Your Aerial, by Harold Day. Facte for Beginners, by Fred. Chae. Bhlert JULY 82. When Your "Movies" Come by Radio, by Stan- ley Bryant. Underlying Principles of the Vacuum Tuba, by George W. May. Practical V-T Detector Panel, by Rumford. Revised Radio Dictionary, by Bhlert The Beginner's Cateehlsm, by Bdward Linwood. Importance of Aerials to Radiation, by C. White. JULY 90. The Vacuum Tube aa a Transmitter, by Charles H. Plath. My 90-Kll«watt Tube and Its Uses, by Irving Langmnlr. Importance of the Capacity Switch, by B. L Bragdon. The Truth about Harold R. Hart AUGUST 8. How to Construct and Operate the Superregeneratlve Circuit, by John Ki Using Radio Frequency to Extend Range, by Q^h?ni^ Every Radio Fan Most Know, by B. B. Hawley. _ _. Revleed Radio Dictionary, by Fred Charles Bhlert AUGUST 12. The Work of the Audio-frequency Transformer, by George W. May. Practical Measurement* of Capacity and In- duetanoe. by W. A. Dickson. Experimenting with Armstrong Circuit Pro- duces Unusual Hook-up, by Dr. O. S. Kelly. How to Seen re Perfect Regeneration, by Fred. Chas. Bblert AUGUST 10 How to Build a Portable Field Busser, by De Witt H. Thompcon. Using Two Tubes for Receiving, by C. White. The Storage Battery aa an Important Factor In Radio Reception, by Donald Van Wyek. The Use of Capacity In a Circuit, by George W. May. The Beginner's Catechism, by Bdward Linwood. AUGUST 20 How to Build a Splder-Web Reoelver, by Frederick J. Rumford. My Detector and One-Step Amplifier, by Fred. Chas. Ehlert The Beginner's Catechism, by Bdward Lin- wood. Hints for Fans, by C. F. Rye. SEPTEMBER 2 Generating C-W for Transmission, by C. White. Wonders of Radio-Frequency Amplification, by H. 8. Potter. How to Connect the Electrlc-Llght Socket Aerial, by John Kent Practical Circuits for Regenerating Loud Sig- nals, by O. 8. Kelly. SEPTEMBER 9 Radio Ideaa for the Amateur to Teat Out by Carl Maaeon. How to Make a Practical Wave-Motor, by Frederick J. Rumford. How to make a Honey-Comb Ooll with * Two- Stage Amplifier, by Fred. Chas. Bhlert Perfect Short- Wave Radio- Frequency Ampli- fication, by George W. May. SEPTEMBER 18. How to Make a Two-Tube Soperregenerator. by Frederick J. Rumford. Methods of Amplifying Radio Signals, by B. Bradbury. Voloe Distortion In Vacuum-Tube Receivers, by W. A. Dickson. Charging a Battery— from a French Radlolsf s Point of View, by Marlua Thouvals. Working Diagrams for Beginners. SEPTEMBER 23, 1922 New V T Hook-up Worth Testing Out, by P. F. Metaler. New Method for Lighting Filaments, by C White. Why the Radio Compass Is the Fighting Element of Science, by Ortherua Gordon- Complete Table of Symbols Used in Radio Reception, by Fred. Chas. Ehlert. The Radio Primer, by Edward Linwood. Complete Method for Building an Electron- Tube Detector Unit, by Experts of the United States Bureau of Standards. SEPTEMBER SO, 1922 Increasing the Wave Lengths of a Receiv- ing Set, by George W. May. The importance of the Variometer to a Re- ceiving Set by Donald Van Wyck. Successful Stunts of an Amateur Radlolat by C. F. Rye. Employing Jacks with a Two-Stage Ampli- fying Receiver, by Fred. Chas. Bhlert. OCTOBER 7. Superheterodyne Receiver as Applied to the Armstrong Superregeneratlve Circuit, by Charles R. Lenta. b^c'w^" * RldioFre<,nency «—•*»*'• Why the Open Antenna Is Best tor the Radio Listener, by C D. Wegener. Broadcasting Stations of United States and Canada. The Radio Primer for the Beginner, by Lynn Brooke. OCTOBER 14. Neat Home-Made Tube Socket, by Gordon S. Arthur. Vessels Now Guided Through Fog by New System of Radlotelegraphy, by Otherua Gordon ..What Makes the Receiver Work, by Donald Van Dyck. Using the Varioooupler in a Short -Wave Re- ceiver, by George W. May. Regenerative V-T Receiver for Short Wavee. by Fred. Chas. Ehlert OCTOBER 21. Important Improvements in Radio Receivers, by G White. Be Sure of Your Ground Connection, by Fred. Chas. Ehlert. How Radio Was Installed in Our Home, by Hattie Briggs Hartman. One-Tube Regenerator Hook-up for Loud Sigs. by Harold Day. Every Radio Set Has a Reliable Range, by John .Kent. The Theory of Radio Communication, by Horace Beers. OCTOBER 28. A simple Super-regenerstive Receiver, by Har- old S. Potter. Vacuum Type of Arrester Safe, by Fred. Chae. Ehlert. How to Make Your Aerial Function, by Horace Beers. How to Avoid Interference When a 30 Meter and a 400 Meter Station Are Operating Simul- taneously, by C W. Horn. NOVEMBER 4 Receiver for Amplifying Weak Signals, by Hoe- ace Beers. How' to Learn the Code, by Ortheras Gordon. Detectors— and How They Work, by Donald Vsn Wyck. One of the Most Delicate Parts of s Receiver, by George W. May. , Wave Meter for Amateur Operators, by United States Bureau of Standards Experts. NOVEMBER 11 How to Build s 100- Meter Concert Receiving Sat, by Frederick J. Rumford. Wide Field for Experimenting with Aerials, by Donald Van Wyck. Single-Tube Superregenerative Receiver, by C White. Utilizing Ford Spsrk-Coils for Audio- Frequency Transformers, by Ortheras Gordon. Why It Is Necessary to Tune In, by Arthur G. Shirt. Any single copy of Radio World, be- ginning with No. 1, mailed on receipt of 15 cents postpaid. Any seven issues for $1.00. All 43 issues to date for $&5w. Or send $6.00 for 1 year (52 nambera) axed have your subscription start from No, 1. Radio World. 1493 Broadway, New York. Digitized by Google

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RADIO WORLD 27 DO YOU WANT TO BUT, SILL OB DBF/ ■GB BADK> OB AT fa A WOBi OTHBB GOODS T TBT THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department is intended for ereryfcedy »irfk»wgjny or general merchandising in the n*dfa fseld. every week. Adrertitert will get a ten-day on the news-stands ten days after copy action on short anno— cements eratint the . of RADIO WORLD wB fad that it pays to read is, copy recti Ted for this department will appear in RADIO The rate for this RADIO WORLD QUK&VACTIOM CLASSIFIED AD. DBPT. is Sc. oer word (minimum of M including address), 10% disconnt for 4 cceweeoaWe iaoertions, lift f or 13 coeoecatiTe hwerfasis & omnths) Oassjeswirhe i fen standing classified ads. if copy is received at mm effae ten days before pohheatma. RADIO WORLD 00, MM Broadway. N. Y. C (Phone, Bryant 4796). HAVE YOU SEEN IT? Mr unusual tally Il- lustrated radio catalog it complete. Only a dim*. N. E. Biatcy, Sprint Gtotc, Minnesota DEFOREST TWO STAGE AUDIO AMPLI- FIER, in Cabinet, guaranteed. Piret $30.00 take* h. F. J. Jordan, UB So. Weadock At*., Saginaw, Michigan. STOP PAYING FOR BATTERY CHARGING! Sulphate eaoac* moat defecta; end yew troabtae by Being Oe-SnlphaU; harmless, guaranteed. SLOO bring! yon enough for lour bntteriee. In- atructions lor naing. W. L. Green, Monroe Ctty, Mo. LET- VACUUM TUBE RESULTS WITH A CRYS- TAL SET! Uee a TT Ultra -Sen nitiTe Can tact in your Crystal Detector. Be ordinary catwbiakera. Myrts ' Wiaoontin, write*: That *FT aau gold ■ WoodTRb . . FTUltrn Cryetal Detector Contact I purchased ie aura a Uaheg the TT* Contact end' _ hare heard peer 43 diauraat braadcaatjaaj statl • The •*T fcrnT 1 imwi JOLLY. . through our club. Betty Lea, Inc., 4254 Broadway, PATENTS— Inventor* abould write (or Free Guide Books and Record of Invention Blank be- lore dascioniag invention. Send model or sketch uf your invention for our Free opinion of Ma nutentable nature. Radio, Electrical, Chaaakal, Mechanical and Trade-Mark expert*. VICTOR J. EVANS 4 CO., M4 Ninth, Washington, D. C TWENTIETH CENTURY BOOK OF RECIPES, FORMULAS AND PROCESSES-Edited by Gard- ner D. Hiecox. Thia book of 800 page* it the moat complete book of recipe* ever pubBabed, giving tbounand* of recipe* for the manufacture of vara- ■Me article* tor every -day uee. Hints, berps. practical idea* and »ecret proceese* are revealed within it* page*. It cover* every branch of the useful art* and tell* thousand* of way* of making money and ia jnat the book everyone should have at his command. The pagea an filled with mat- tore of intense interest and immeaaurable prac- tical value to the photographer, the perfumer, the painter, the manufacturer of gins*, pastes, cement* and mucilage*, the physician, the drug- girt, the electrician, the dentist, the engineer, the foundry man, the machinist, the potter, the tanner, the confectioner, the chiropodist, the man- ufacturer of chemical novelties and toilet prep- arations, the dyer, the electron-Inter, the ennuMtur, the engraver, the glass worker, the gold-beater, the watchmaker, the jeweler, the ink manufac- turer, the optician, the farmer, the dairyman, the paper maker, the metal worker, the soap maker and the technologist in general. A book to which you may turn with confidence that too will find what you are looking for. A mine of information up-to-date In every respect. Contain! an fan- n»nnae number of formula* that every ■! ought to have that are not found in any other week. New edition. 807 octavo pagea. Cloth binding. Price, $4.00. The Columbia Print, 1493 Broadway. New York City. FOR SALE— A Inrge number of 1 step amplifier*, assembled but an wired. Price $5.25. Also 16.50 type Home Variometer* and Variocoupleri. Price $3.25. 43 plate condenser*. Price $2.75. Audio and Radio Frequency t ran if or mere, $2.50 each. Franklin Campbell, Jr., 414 High St.. No. Medford. Man 'up «n Lw» _ oaived over LM0 mBes. when vacuum tube* ; fnflnd. Price only twenty-five cent*. TT" CRYSTAL CONTACT MASS. COMPANY. Bos U41. BOSTON. STANDARD ELECTRICAL DICTIONARY— By Prof. T. C Conor Sloan*. Just iaaued an en- tirely new edition brought up to date and greatly bonk this work i* beyor ' ork City. enlarged na a reference this < rk i* 1 comparison, aa it contain* over 700 pagea, nearly 500 illustrations, and definition* of about WOO distinct words, term* and phrases. The deftni- terse and concise and include every •Sed in aw.utiU.al acieacn, 7u7 pages, 477 ign IS for fuller description.) tun bis Print, 148) Broadway, tares used in anwuna illustrations. (See peg Price, SUB. The Cola NewYork Chy. MILLION POINT TESTED , CRYSTALS- Mounted in Woods MetaL These Anuria Crystal* as* tested and are guaranteed or money itlnnned With so many sensitive points, it is baponnibl* to miss contact. Stop wasting tfan* and send us 30c for one Adbrin Crystal or send SL» tor MX, mailed prepaid. Also write us tor information aa we have other styles, including our new type combination twin Galena and Rarincns. BfcOte Radio Panel Boarda. ineulated, rubber base, cut. bored and drilled with ordinary tool* without spoilage. Sis** can be furnished cut to your re- quirements up to 22x21x3 /J*. Writ* to na for price* or aak your denier. DIOUTB IN- SULATOR CORPORATION, 287 New York Ave- nue, Brooklyn, New York. HOW TO BECOME A SUCCESSFUL ELEC- TRICIAN—By Prof. T. O* Conor Sloan*. Aa in- teresting book from cover to cover. Telling In nfanpkut language the surest and easiest way to become s successful electrician. The (todies to be followed, method* of work, field* of operation and the requirements of the successful electrician are pointed out and fully explained. 282 page*. Ifluitrated. Nineteenth revised edition. Cloth. Price. $1 50. The Columbia Print, MSB Broadway. New York City. MODEL MAKING— By Raymond Francis Yates. A new book for the mechanic and model maker. This is the first book of it* kind to be published in this country, and all those interested in model engineering should have s copy. The first eight chapters are devoted to such (object* as Silver Soldering, Heat Treatment of Steel. Lathe Work. Pattern Making. Grinding, etc. The remaining twenty-four chapters describe the construction of various models such as rapid fire naval guns, speed boats, model steam engines, turbines, etc 400 pates. 301 illustrations Price. $3 00. The Tolumbia Print. 149J Broadway, New York City. A COURSE IN MECHANICAL DRAWING— By Louis gouillion The author ha* written a moat practical book on the subject of Mechanical Drafting. It fully explains the art of Drawing, Lettering and Dimensioning. It is, by tar, the most practical book ever published on thia sub- ject, for us* in day and evening school*, and more especially adapted for the teacher and for self instruction. Fifteenth edition, revised and enlarged. Fully illustrated. Oblong. COLUMBIA PRINT, 1493 Broadway. N. Y. C ' MAKE MONEY silvering mirror*, all kind* plating, knives, spoons, auto headlight*. Outfit* furnished. Free booklet. International Labora- tories, Dept. 310, 311 Fifth Ave.. New York. WIRING A HOUSE. By Herbert Pratt. Shows a boast already built; tell* just bow to start about wiring it; where to begin; what wire to uee; bow to run it according to insurance ruins; in fact, just the information you need. Direction* ap- nly^equnfly^to a ehop. Sixth edition. COLUM- 2* cants. M83 Broadway, N. Y. C Prion, CASH FOR OLD COLD. Platinum, Silver, Diamonds, Liberty Bonds, War, Thrift. Unused Postage Stamp*. False Teeth, Magneto Points, Job*, Any Valuable*. Mail in today. Cash sent, return malL .Goods returned in ten days if you'r* not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. OLD MONEY WANTED — $2.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book. 4x6. You may bare valuable coins. Get posted. We pay CASH. Clarke Coin Company. Ave. 8J, Le Roy. N. Y. NEWS AND GOSSIP OF THE STAGE — Send 10c. for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.00 year, $2 00 aix month*, $1.00 three month*. New York Star Co.. 1493 Broadway, N. Y. STUCK?— Let me noire your Radio receiving problem*. Service charge. 25c per question. Fred- erick Barber, 216 Jasper St., Syracuse, N. Y. SUPER-SENSTTTVE GALENA— Nature** only perfect crystal, unmounted, 20c: mounted. 25c. (coin). All guaranteed. M. Skeffington, 148 Reve " Walnut Ave., vere, at as a. MAKE MONEY AT HOME MAKING TOYS and novelties. Send 5c for samples and particu- lars. New Specialty Co.. 417 E 71st St., New York. I with bi Wand* everywhere- OVERSTOCKED. Must sacrifice Dc Forest MR- 6's. Magnavox. and other goods. Write at once, uantity limited. Hobart Radio Co., Hooart, Heard at the Radio Counter A CoT4V*r»ution Between Customer and Radio Ctark. Part XII. right." ^Why, COD DAY, Mr. Jon**! How dM that new circuit of yours work out 7** d nana! Fbsst But I need some addt- t tn get H wart tug nhn*tutnty 1^ thought you and bought everything "Well, you see I tried to ahhstp a bit, sad. of course, you can't take half n awns of midlrlni and nxpect resort*.** "Not very w*L But. tuB me. want is the trouble 7" "1 dont exactly known; but. as pan gave as* Good Luck and Happiness .Twill tdl VOU lJnd,r which Zodiac Sign were you born? What wtwaurt Tl Tour opportunities In life, your future pro»- ■V Lf* m\ m\ Pecta. happiness In marrtare. friends, enemies. ■ * BV U M M m succes* In all undertakings and many other vital queatlona a* Indicated by ASTROLOGY, the moot snclent and Interesting science of htetoryT War. you born under s lucky start I win ttll res frss. th* nest Insrvstlat as tmloslrsl Interpretation of the Zodiac HI en you war* barn under Hlmt'ly sand me the sssct date of your birth In your own handwrltlne. Tn sorer his ntrtic* and postage, snoJoae ten osnts In any forsi snd your mut naiao MS Tour astrological Interprets tlnn win bs wrttuai In plain lanevaes to you seeursly soalsd and postpaid. A treat surprtss swells yeal now — TO- DAT — to the »HTA 8TCD1Q. 308 (Dept. P) Fifth Avenue, New Tork Ban * and »■ and ■ Wrtl the csreaut, I tbsngbt yea enssd aiskably hats nan watt. Here I aasd a 48888 and here I need a a .8888 mad s .888. I realty ena't awl whs alaT.renra bee; but I don't get aa good aa yon nay I afcaald; a* I brought the d aad also the nilmin, and thesaght pan tsB an* why S* cbnag* Is "Wal l thbsh I can change an* tar you. You can keep tho J88S assd as* It, but the jm wfB oast you aanrs. Tbi* drcnlt is known as a capacity -conpled carcwit. TVs fact that tnsmlliig 1* p hs th* ch-cait have th* enpneitina "Well, an laag aa It ie correct, why I ****** change tt. And how aanch will it cent. By the way, yon can giv* use another set of those salsa daaphraeraa for my phessan ■ They work perfectly, ■Jthoalgh I was kind of scary shunt thews at ftret.4 "They are the only one* tn nan. They have n pure team, wbar*** other* anight band t* gtvs a "O. IC Old Msal Drop saans night whoa you hnv* nothing eta* on yn mind. Vm going to change It end got M wr- ing ns-ulght. Maybe you would Uhe tn ens-, and work aa It with as*. What aay*T Digitized by VjOOQLC

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28 RADIO WORLD Let Radio Our List IMoo »8.00 Elsemann Phonea J5.25 16.01 Wetit«m Electric Phones extra ear caps and muf- fle™ 7.50 S5.0S Federal Jr. Crystal Phones 12.50 FcXlex^arl0'°etr" 'n<12 75 1.50 Klosner Vernier' ' Bheo- Btats 95 5.50 Workrlta BaiellU 180 Coupler 3.50 1.0* Paraian Bakellte Socket. .60 1.T5 Bright 8tar "B" Bat- teries 1.15 Write lor free catalogue I IS Weal 23rd Street. Naw York Perfection Radio Corp. of America EVERYONE in RADIO should leers tks WIRELESS CODE Before the CORYDON SNYDER CODE METHOD was invented, the hardest part of learning was memorizing the code sig- nals for the alphabet. Now anyone can memorize them easily within 3 hours. Send $1.00 for this home study course, or sign form below and send with your address for one week's trial To CORYDON SNYDER, Utl So. Ridgeland Avenue, Oak Park, HI. Please send me the CORYDON SNYDER CODE METHOD. I have not yet memorized the code and wish to do so. I will give your method a fair trial and will send you one dollar within one week or return method if I can not memorize by it as you claim. NAME YOU DX HAMS! Hire you wen the hook-up with complete panel layout in full also and all constructional details H RADIO WORLD No. 43. dated Jan. 101 This hook-up actually goes out and drags the dlatanoe in, and lays It at your table. It's a wonder I Can't be beet! Kran If you never hare made a eat yourself, yon can do It bow. All that la necessary Is to lay the full -page diagram at the panel on your own paaal and drill and mark your holes. 81mple. Isn't Itl If you haven't thla copy send 15 casts to Badlo World. 1493 Broadway, New York. N. Y., and copy will be mailed you. Or start your subscription with that number. Direct Radio Communica- tion with China SAN FRANCISCO.— Announcement of a new pioneering step in radio is made by the Federal Telegraph Company. This con- cern, which established the first radio com- mercial communication with the Hawaiian Islands, now has established the first direct private radio communication with China. While this latter service is not on a_ com- mercial basis as yet, pending completion of the first of five large stations the company is erecting in China, all its own communica- tion is being carried on over it. The Federal's Hawaiian service was opened in 1912 between stations at South San Francisco and Heeia, island of Oahu, which virtually are duplicate installations. They since have been sold to the govern- ment. Until 1914 communication was carried on only at night, but the service was adequate to supply the island news- papers with their first metropolitan press service and to exchange a number of com- . mercial messages. The new communication channel with China is from the Federal company's Hills- boro station, near Portland, Oregon, where one of the arc sending-sets used regularly in its Portland-San Francisco service has been diverted temporarily to send to a tem- porary station located in the Astor Hbuse, Shanghai, China. Communication is on a wave-length of 8,400 meters, and has been carried on thus far with a power input of only 30 kilowatts, less than half the capacity for which the arc was designed. stration last night, however (for which the credit must be shared by Mr. Thayer's organization and the Radio Corporation of America), is vivid and dramatic proof of the giant strides in the progress of the art- Practical use of wireless telephony in trans- atlantic communication is still some distance away, for the number of wave-lengths avail- able is still so limited that not more than four or five such conversations are simul- taneously possible. But no one can doubt, in view of the record of the recent past, that these difficulties will be overcome. RADIO PANELS Cut exactly to size and shipped within II hours. .14 Inch thick. IV10 per square inch, g/le Inch. lUc per square Inch. Hade of the highest grade black fibre. Thla material possesses high dlaleetrls strength. Is Inexpensive, unbreakable, easy to work and takes a nice finish. Special offer, SxIxVl. 50c; ex liiM. $1.00. Postage paid. WILEY PANEL CO. 2323 Ss. Central Park Ays.. Ck. tease. III. "This Is Mr. Thayer" WHEN the telegraph was completed the first long-distance message success- fully transmitted consisted of the words "What hath God wrought 1" The telephone was first used for the prosaic command : "Mr. Watson, come up here. I want you." To these historic utterances, says "The Globe," New York, must now be added "This is Mr. Thayer." Last night H. B. Thayer, president of the American Tele- graph and Telephone Company, sat in his office at 195 Broadway and, introducing him- self with the words quoted, talked across 3,400 miles of tumbling black Atlantic water to a group of men in New Southgate, near London. His words, carried by the magic of wireless telephony, were transmitted almost perfectly; those of his hearers in England who knew him recognized his tones. Mr. Thayer and several other speakers were heard to the extent of thou- sands of words, and so distinctly that the jovial British listeners were able to register a humorous complaint of the American accent. This achievement does not come upon us unawares. Radio telephony from Arlington to Paris was successfully experimented with as long ago as 1915, and only last month a woman singing in Newark was heard in Croydon, England. The demon- TRADE "VAC.8HIEi.tV MARK Patet.. . ... Your Tubes Need VAC -SHIELDS BRING IN D. X. The invention of this non-magnetic shield cuts out electric-static effects between vacuum tubes, over- comes interstage coupling, which causes distortion and unnecessary noises which make it difficult to tune in distant stations — also guards tubes against breakage. Your tubes should have them. Attacked in a minute Price prepaid by mail $1.00. ORANGE RESEARCH LAB. 41 North 16th Street East Orange, N. J. WE ARB MANUFACTURERS OF FINE RADIO FURNITURE— CABINETS, TABLES AND ROLL TOP DESKS. Hardwood, fcsuid-rubbod, mahogausjr and goMoa oak finish. Postage and Express paid by us. It will pay you te send far priests and description. THE SOUTHERN TOY COMPANY Radio Division Hickory, N. C A high-grade Headset of stand- ard aluminum construction, at a price that appeals to the average purchaser of radio apparatus. CLARION RADIO HEADSET $5.00 The Clarion Headset is guaranteed to give perfect satisfaction o r purchase price will be refunded. Circular 21-A, mailed free on request is of interest to Jobbers, Dealers and those desiring a high grade head- set at moderate cost. Radio Supply Company ized by HORNELL, N.

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RADIO WORLD 29 RABIO TOOL SET CF.B CO, IN Park Plana, Not Teak CJty » STATES IN S NtCMTS WMfk Baaatoea |fes *• ULXKA-AUDMN (Al Warn tel aaa be tar fen mm III. OtmfUt* tmtTMCttmu (J RADIO DESIGNING CO. Guaranteed March BavikM m T«M DtlwOl Tabes •».•» OM*bm, ll tnne. •Man * 41 ▼•• -a- mmn—i~ NB.....ILN ■tit Tan -■- Ballerlee.. it* Oana WHfe Orete r STANLEY RADIO SUPPLY CO. It* Baal *M H*M* Maw Tark Book on Chemistry «• IHU Ml UNI van at mm bash to _ ead oloetra otwalsel eipsrlasets. 71a. - lin a ii« ■■ N. T. 0. AUTOMOBILE CHARTS Br Vleber W. Peen, M. S. A. B. UeMera ttm U Mk • M la. — I"*!" lie. Cm*. UsaUsa at Igareoa breaee TneMas Mi* fcey. la tkie Man all wu of a UTrteeU dsuMeifatat- rJea uilm eataf •»««•» and anunMa iMiaM an am. awl annaeUeaa an sitae far raadUr Sedbas UaMtae trseblaa and ejlariaetM *aai wham feaand. Intladea latest Daks, Cooaialiet aad acker ejansss. (14 I II.) Prise. II starts ■ — at Oeoakri and LabrloatJa* TraaMaa. la a eewafeaHon abort annates aU •an- te' tka approtad fern at ereier aaalku Uawwaltoa at rba Malar Oar , , IMa Mart proooaoe Ik* plea else at * tlllMl att^aUaoar eaaeate at ataadard eaten sad aakVsas all Taeerlaal eaarta* polnta raaalrtaa I " ttaa, awl la a talaakU stride la *a lohnooltoe at ear —dam aac. A tat aU tattteaud la aaur ear (M 1 II.) Pries, u aaala I at dm abase tbrae stesrts la aaa* it earn all aalataaaaaa lailiaslleae i aaawMalw. UMMia at ttartiai aad LI eat las tlKa FaeMa. Ike eMet eoapleto than rat detiaeu, ahoaiaa aU parts of tka aMafera aaiiaillla aurtina. llaMlar aid lnltlea erateeae, iMh laatrajotlera far «■■ teotaUa woollen at aU faulu la virtu, loans, aaur ar atnaraiar, awliekae and all eeter aalta. laraluaata le aeeaorUU. aaaetreero aad re- paineae. Slat 14 I II loeaoa. rrtaa. II • Liaatlia at Far! let 1st TraaMaa Mads bar. Am salaried aad retleod ehart ekeerlu atoar I drpledris all porllona at tha rani paver piaat aad euitlury croupe. It awtilnae ekaarlr an pane at the castas, foal super; muaa, lanstjsa map aad eootlni artien. that are apt la giro trouble, dotal Una aU dmosaaxnu that are llaMe at Make ea rnalne lose i*s*tr, atart hard, at wark ImauUrty. Tkla ekert aimptlQca loeetlea af ail eaclae faulu. aad lnclupititl Fund by the Kev. Ur. Ernest M. Stires in re- sponse to his radio appeal broadcast from the pulpit of St. Thomas' Church, ot which he is rector, wai announced at a meeting of the trustee! of the fund, at which William Fcilowes Morgan was elected president. No Free List Radio World has no free list. The only copies sent out by the publish- ers are to fill the ever-increasing orders of the American News Com- pany, the large numbers of subscrip- tion orders received at the otTice of publication, and one voucher copy to each advertiser and advertising agent represented in current issues. RADIPHONO ADAPTER $2.00 ■ ■■■■■■■■■ SURPRISED? Fast Ml. RADIO MYSTERY TRACKED IV WIRELESS WILLIAM LE QUEUX Author of "MsuUnsoiaarU of M Mr. La Carlo," Tha takrlgMn,- FkBe-aw," ota. f Erary raelie faa ahoah Latest Bystary story hy Qssaaur. who so rightly h eallad, Tha Master al tha Story. 1 This is fictioa best Mr. La Qwu W • i— h.w al tha I aetata ta of turn* Eagiaears aad iWare wall fitted to writ* this 1 Tha plot la Ha is ■pen hy Seotlaied Yard to aid la tha aeteetiea af a bead of criaaiaeUa arha have termed the aaa al ahslsn lata lawless shaaaals f Fslssasr arm hastily sal roe tha aiystery daring which the lataet anf laa fas radio dew alee) tha radio of today aad tha radio ot l/ie future. Tha bajesk yea eaaaot afford to f Oar spocial arte* to raaiai Raelie World— for a liautod ealy — tl JS postpaid, ■nonary eider. Moffat, Yard mnd Si Union Saner* Was* New York City Brr-aHcaMing map. 15c. That il. a complete lirnadca-ling map appeared is I<Ai'i'« Wimin. No. R. datcl May 20. Mailed on receipt of 15c Radio World Company. 1493 Broadway. N. Y. C. Digitized byVjUOv IC

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30 RADIO WORLD Uncle Sam Needs Radio Workers United States Civil Service Examination for Radio Inspector to Be Held March 7 THE United States Civil Service Com- mission announces an open competi- tive examination for radio inspector on March 7. Vacancies in the positions of VACUUM TUBES DETECTOR Guaranteed at $L50 AMPLIFIER Guaranteed at $2.75 "B" BATTERIES 22% VOLT Guaranteed $0.65 4SVolt $£25 W. D. 11 SOCKET Bakelite S0J5 PHONES as per last week's advertisement. Pottage mutt be included with order. Check* mutt include 10c. exchange and pteate have them certified. All goodt are thipped P. P. insured. RADIO DISTRIBUTING ft AUTO SUPPLY COMPANY M West Nth Street, New York City Phsns Columbus MM Broadway -7th Avenue Subway 6th or 9th Avenue L CONCERT LOUD SPEAKER Complete with unit and ear*. Beautiful cabinet type, wonderful tone. Fully guaranteed. Poet- $19 (A Mid (C.O.D.) »".OU L. D0NNELL MFG. CO. Bex 70 Ass Arbor. MM. radio inspector and assistant radio in- spector in the Bureau of Navigation, De- partment of Commerce, at $1,800 to $2,200 a year (plus "bonus," see below), and in positions requiring similar qualifications at these or higher or lower salaries, will be filled from this examination, unless it is found in the interest of the service to fill any vacancy by reinstatement, trans- fer, or promotion. Range in •alary.— The entrance salary within the range stated will depend upon the qualifications of the appointee as shown in the examination and the duty to which assigned. Bonus. — Appointees whose services are satisfactory may be allowed the increase granted by Congress of $20 a month. Citizenship and sex. — All citizens of the United States who meet the requirements, both men and women, may enter this ex- amination; appointing officers, however, have the legal right to specify the sex desired in requesting certification of eli- gibles. For these positions in the Bureau of Navigation men are desired. Duties.— The duties of radio inspectors will be primarily to inspect the radio ap- paratus on steamships, to insure its com- pliance with the law, and to inspect shore stations. The inspectors may also be called upon to examine radio operators. The duties of radio inspectors require some office experience, therefore compet- itors should outline fully in their appli- cations any office experience they may have had. The duties of assistant radio inspectors will be primarily the assisting of radio inspectors in the enforcement of the wire- less communication laws. Assistant radio inspectors will be required to inspect the radio equipment on board vessels and in land stations, which involves the carrying of 30 or 40 pounds of testing and measur- ing instruments. The inspection work re- quires a knowledge of the installation and operation of the several types of radio in- stallations, including the adjustment and tuning of transmitters and receivers. Subjects and weights. — Competitors will be examined in the following subjects, which will have the relative weights in- dicated : 1. Theoretical and practical questions in the construction, use, and ad- justment of radio apparatus and auxiliaries (eligible rating re- quired) 50 2. Education and experience in the line of the required duties 50 Total 100 Applicants must attain an eligible rat- ing in the first subject. Education and experience. — Applicants must have received a bachelor of science degree from a school of recognized stand- ing, such educational training to have in- DELICATE SOLDERING solved by the instrument ussMtinutad far Oris particular purpose. THE POST SOLDERING IRON Platinum Heating Unit— Interchangeable Tips— Universal Current (Large and Bmall) 9640 V -rtiflcate ef K OOMPAMT, or Writs N. T. Evening Hail Radie Institate 509f> 38 E. 42a*J St, New Terk FREE SHSLTOKK LOUD SPEAKER With nary pair ef OrUlnal Nathaniel Baldwin Otaspaw* T7P* O Haadaat At flzjf Tbia Lead-Speaker rococo! aed by expert* as the best for true tone, deameeo sod design. Cath with order or C. O. D. WALTER SCOTT IS St. Lukes Pesos Upper MsaMaJr. Near Jersey BltCANTO - ■ inaas-oaoaar . — Clear, resonant, mellow-toned as an old violin, the BEL-CANTO AMPLIFIER stives in its original richness, the riving voice of the artist, or the most delicate tones of an orchestra. Paderewald, the world a moat famous pianist says of it— You are indeed to be congratulated upon your ingenious invention." Adjusted for the following circuits: Be- generattve two stages of amplification for stations within SO miles. For long dis- tance reception $ tube radio and audio fn- 2h^fy °!Ieuit- ,Specia' ««™ sensitive t°0. B.mNew*mY,ork.00rd "nd •» Bel-Canto Corporation 417 East 34th Street, New York City Di eluded a special course in radio or kin- dred sciences, or show that they are senior students in such institutions ; or have had the equivalent of a high-school education and at least two years' experience in spe- cial radio work, such as the manufacture, installation, or adjustment of commercial or governmental wireless apparatus It is essential that applicants be wireless' tel- egraph operators. Statements as to education and experi- ence are accepted subject to verification. Applicants must have reached their twenty-first but not their fiftieth birthday on the date of examination. These age limits do not apply to persons entitled to preference because of military or naval service, but such applicants must not have reached the retirement age. Retirement. — Classified employees who have reached the retirement age and have served fifteen years are entitled to retirement with an annuity. The retire- ment age for railway mail clerks is 62 years, for mechanics and post office clerks and carriers 65 years, and for others 70 years. A deduction of 2J4 per cent is made from the monthly salary to provide for this annuity, which will be returned to persons leaving the service before re- tirement with 4 per cent, interest com- pounded annually. Photographs.— Applicants must submit to the examiner on the day of the ex- amination their photographs, token with- in two years, securely pasted in the space provided on the admission cards sent them after their applications are filed. Proofs or group photographs will not be accepted. Photographs will not be re- turned to applicants. (Continued on ntxt page)

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RADIO WORLD American Radio Stores Douhla Clrcttlt New W. D. 11-Tuha Sat, wttk A A B Btwtariaa. Latlda Ux7. Oak Caktaat. Coaapbta wtth tt Taatad Bafara SPECIAL, $30.00 Attach Aateana ud Ground mmd gat DX. TUBE SET 1 W. D. U Soekat 1 W, D. 11 Tuba 1 Cria Laak Cawd 1 "B" Battary. »H ** 1 "A" Battary, dry cal 1 *V Plata Win tar Hook Up Praa wttkSat $10^ ut 4.TS US American Radio Store* 11 West 37 StftofmrnMewYorlC The Volume of the Atlantic and the Smoothness of tho Pacific A & P Loud Speaker makes a theatre of your home. Every note will sing out as if the Broad- caster were right in your Speaker. Why listen to stuff that sounds like a tired phonograph record when the A. & P. Phone LOUD SPEAKER gives faithful reproduction — with triple volume, clear and sweeter than very expensive speakers. $4.95 POOTAOE PREPAID VONBT BACK GUARANTEE D»lm and Jobber! wilt* for Pramltlon. Note: TIM A. * P Phone Lnwt Ppeakrr ow*4 Ita quitttr to the Saatlal Allay used •nj to th» amllar AaMli Praatrtlaa tf Itt daalaa. WE CARRY A COMPLETE UNE OF STANDARD PARTS AT REDUCED RATES {Continued from preceding page) Resklanc* sua" dotwiciU. — Applicants may be examined at any place at which this examination is held, regardless of their place of residence; but only those who have been actually domiciled in the State or Territory in which they reside fon at least one year previous to the ex- amination, and who have the county offi- cer's certificate in the application form executed, may become eligible for perma- nent appointment to the apportioned ser- vice in Washington, D. C Oral tiiminitiea. — Applicants may be required to report either in Washington, D. G, or elsewhere, for oral examination to determine their personal characteris- tics and address, tact, judgment, adapta- bility, and general fitness for the perform- ance of the duties of the position. An applicant who fails to pass the oral ex- amination will not be eligible for appoint- ment Applicants will be notified of the date and place of the oral examination. Application*. — Applicants should at once apply for Form 1312, stating the titte of the examination desired, to the Civil Service Commission, Washington, D. C, or to the Secretary of the United States Civil Service Board at any place listed hereon. Applications should be properly executed, excluding both vouch- ers and the medical certificate, and filed with the Commission at Washington in time to arrange for the examination at the place selected by the applicant Radio Jokes A PAIR of femes snapped good and tight The Radiotron burning just right He tunes 'em in right through the night That's him!— "The Radio Log* "Friends, Romans, countrymen, lend me your ears!" cried the orator. "Evidently he wants to listen in!" we cried.— "New York Herald." Jimmy— -You take this wireless receiver I just finished makin', and go down stairs in the cellar; hold it close to your ear sad lis tea Freddy (after waiting in suspense for several moments in the cellar)— Aw, it's a fake. I didn't hear a thing. Jimmy— Good! That shows it's worlrin* right I didn't say anything yet— "New YorkMaiL" J. G. Hibben, president of Princeton Uni- versity, in an address recently, stated that by means of crude apparatus a wireless message was sent some 250 feet at Princeton, in 1832. SEND ME YOIR PHONES for rrpaJra. All raikra Satisfaction ruarantaed. Rraaonatila chart**. Boy, 101 Waal 4 tad St.. Now Tart City r\ r HEADQUARTERS UC rOreSt Conplata Stock- AD Sata, Parti, Tub**, Ajcaaaorlaa Reliability — 8«r»it* — C*-«a«rattM RADIO STORES CORPORATION 220 WEST J4TH STRICT, s .Y. CITY L*a***r* 101101211 Subscribe for RADIO WORLD. $640 a year, $3.68 six months, $1 JS three . .^JggPE^Py | ALL AMATEURS JM- "I^S* •**J^S. aa faSMRE Ma, jl Skaii il>d man Win, KAOIO world ~. ird£»d Tvl 'Vt wl 'i "i?'* Of- Car— d WW*. SMLDIO WOSj2>. Ha. If. Oi Hm. » n« 1 r w, u'w tZi^J^L, ^ J JiZfl Wa, S— baakta SStt^CjaW Wlr*. S4PIo/wgtl35T>l»,_ tl, »« D« t, g«,t JUi^"1 ■Sanaa a ^t. «an m «jb*• •• • ft Laattka -Saaainwl" SI Aaaa Typ. A IS TYaadfarwara I II Stand kadi* finiani TYaaa- ••wata I H laardara Ttnakaai t.SS rT-tii, aOA. lawtlfytaa pv-m ^21*°*- 1 sw'imkai HI ^Mlit^MlI^t"!'''.'*^. .IS .i«t ... 1*m*i. . .11 .Ml . . r~'"tm""- §. I PL TartaMa Caadaaaam. . . . .' 1 tl A. B e tl PI VwiakW Oa»- kaan 1 it 4 tc «| PL TartaMa Cam- - SS pi- T^Ukt.- IU — ■ l-la. Dlala aa t-la inak. tin taak. lit das. 1 II Pubunr imlau u alaB, Sala- T Ortd Laat4 VrtL ITX _l. 1. ud I lUajakaT....... .aa ™tk Tnm. (taata Jaaka 11 naTSa^wLi-* nil .:::::::::::::::::::::.ty nut i.j; i.n j 1. 1 ntsw CATAi^Msrst on aaqrstsT D-X-Radio Co. US Lifcarty Straat Ma* Tartt OtSf- S ff I a , a : t-4f • JS ■ " e it • ast I

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RADIO WORLD SEND NO MONEY Pay Postman C O. D.— Plus Postal Charges for RADIO AT CUT PRICES If you prefer enclose your remittance with order, adding pottage BELOW IS JUST A PARTIAL LIST OF THE MANY BARGAINS OFFERED PHONES aW Ohm* Mutlo on 3000 Ohms Murdock 4M Western Electric 1M U "eluding Kxtra Bar Cap* and fad* I Dictograph Ml SETS $12.50 Muaio Crystal Set; Complete Antenna Equipment; Special SMI 145.00 Dietxen Single Tube Set; Assem- bled in Handsome Cabinet $14X00 De Forest Transmitter 7S.il §61.00 Western Elec. Power Amplifier. .UiM riatol Power Amplifier 2ft. M Bristol Loud Speaker BJS» $25.00 Imported Crystal Set Ml $30.00 Loose Coupler Crystal Set MM BOOKS How to Make Receiving Sets I J% How to Build Loud-Speaker J$ How to Make Radio Frequency Ampli- fier! JO Amateur Radio-Call Book Ml Radio and Model Engineering .11 Design of Modern Radio Seta M Radio Enters the Home M FREE with Every Purchase BOOK OF RADIO BROADCASTING STATIONS Sand your order Fn hs to-day a a* ~ ATWATER-KENT APPPARATUS Transformer IMI Detector Unit «•*• Variometer Ml Variocoupler Ml Coupled Circuit tuner- Unmounted IMI Mounted 1UI Detector, 1 Step IMI Detector. 3 Step IMI 7 NEW YORK STORES Mail Order Dept: 58 Church Street, New York City MISCELLANEOUS Went. Elec Ammeter for Testing "B" Batteries Hydrometers tor Testing Storage Bat- teries $2.25 Glass Enc. Crys. Detector $2.50 Phonograph Attachment $5.00 Mahogany Variometer %2 50 Socostit s .......... $6^00 Bakelite 3 Honey Comb Coil Mtg.. $5.00 4J Plate Condenser $4.00 23 Plate Condenser Frannngham Rheostata '. 2- Inch Bakelite Dais 3 Inch Bakelite Dials 4 Inch Electros Dial W. D. 12 Transformer (or W. D. 11 Tube $1.00 Freshman Variable Grid Leak and Condenser Combined 100 It 7 Strand Aerial Wire Genuine "All-Wave" Coupler 11.50 Cyclone "B" Batteries 50c. S. Pole Switch 75c. Double Pole Switch Acme Audio or Radio Transformer.. ¥i lb. Annunciator Wire Bus Bar Wire per foot $18.50 Homckarger "De Luxe".. $10.00 3000 Meter Coupler JS Jf LIS Ut lJt US ut LB JI 1M CaaJ at Iron National THE GREAT RADIO MAIL ORDER HOUSE NEW RADIO BOOKS Telling How to Operate a Radio Set — How to Build a Set — Principles of Vacuum Tubes and Other Radio Problems Hew to Make Commercial Type Radio Apparatus By M. B. SLEEPER This book describes in detail aaaay com- mercial types of spark and vacuum tube telephone transmitting and telegraph and phone receiving equipment of all kinds. The experimenter will be able to get a world of ideas for the design and construc- tion of his next piece of radio equipment from the very clear descriptions and the 98 clearly illustrated figures PRICE TSc. Radio Hook-Ups By M. B. SLEEPER A book that gives you not only clear dia- grams for all kinds of telephone and tele- graph receiving and transmitting sets, but simple descriptions of each circuit shown and apaces for notea of results obtained. PRICE TSc The A B C of Vacuum Tubes Used in Radio Reception By E. H. LEWIS Assoc. I. R. E. mm4 RasHo laotructsr Written particularly for the person who "knows nothing about radio" but who would like to gain an understanding of the elementary principles of operation of vacuum tubes and various circuits in which they are used for the reception of radio-telegraph signals and ratlin telephone music and speech. Illustrated. PRICE l\M E7 Any a>f These Books Sent Prepaid am Receipt of Prioa. ADDRESS THE COLUMBIA PRINT ROOM 32« 1493 BROADWAY, NEW YORK Design Data for Radio Transmitters and Receivers. By M. B. SLEEPER The only book that fives tables and data for designing, receiving and transmitting apparatus so that you need no knowledge of mathematics. It's the first hook • be- S inner buys after he has learned the use of is phone receiver ■ .PRICE 71a. Construction of Radiophone and Telegraph Receivers for Beginners By M. B. SLEEPER The man who wants to feel the real thrill ef accomplishment, and who is not satisfied in the merely making use of what others have done for him, builds his own radio apparatus. Radio men can follow the data in "Radio Phone and Telegraph Receivers'* with full confidence, because each piece of apparatus described was first made, tested and found efficient before the final design was accepted. Special receivers, both crys- tal and audien. are shown in detail. Regen- erative circuits as well as audio and radio frequency amplifiers ara described with clear photos, diagrams, and Working draw- ings prepared especially for eke noviee and the man who wants to receive the radio telephone broadcast. A special feature is the phonograph type radio act and the loud speaker.. Fully illustrated PRICE Tte. Digitized by Google

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15c. a Copy February 3 $6.00 a Year 52 N»bm WORLD Selective Receiving Apparatus Used on the S. S. Resolute The Telefunkun receiver shown in this illustration is a type of selective receiving apparatus widely used on board ships. It is very flexible in operation and has a reliable range of from 300 to 20,000 meters, covering practically every wave length used in commercial work. C B. Smith, the operator, is seen tuning in. The inductances are mounted with a view to saving space in the coupling ar- rangement. The taps, instead of be- ing varied with switch points and arms, are plugged in. This manner of working, while not as flexible as the former method, is undoubtedly more efficient, since it allows better contact. Not a great deal of tuning, that is, not much Jumping around, is done on shipboard. If an operator is listening on 600, he stays on that wave for some time, while the fine tuning can easily be accomplished by means of the condensers, shown in the photograph below die in- ductances. Most ships, when inter- communicating, use crystal de- tectors, instead of the tubes. If am- plification is desired it is accom- plished by a separate amplifying unit which can be plugged in, but which in ordinary ship-to-ship reception is not used. While, of course, most of the naval ships are using tubes throughout, for both reception and amplification, the regular commer- cial operator prefers the crystal for regular communication, because it is clearer for short distances, and in general is less trouble. A descrip- tion is given inside. rC K.iHf! and Herbert)

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RADIO WORLD IF YOU ARE INTERESTED IN RADIO YOU NEED THESE BOOKS BEST RADIO BOOKS Telling How to Operate a Radio Set — How to Build a Set — Principles of Vacuum Tubes and Other Radio Problems Radio Hook-Ups Br M. B. SLEEPER A book that gives you not only clear dia- grams (or all kinds of telephone and tele- graph receiving and transmitting sets, but simple descriptions of each circuit shown and spaces for notes of results obtained. PRICE 75c Construction of New TypeTrans- atlantic Receiving Sets By M. B. SLEEPER There is a peculiar fascination about re- ceiving radio messages from the high- power stations of England, France, Ger- many, Russia and Italy, as well as those located in the Pacific Ocean and the Orien- tal countries. Several types of simple re- ceiving sets for this purpose are described, with detectors and amplifiers to accompany them. Suggestions are also given for oper- ating relays and reproducing the signals on a phonograph. Schedules of operating time for high-powered stations are given. In addition, there is some valuable data on home-made wavemeters for testing and ex- perimenting .PRICE 75c. Wireless Telegraphy and Tele- phony Simply Explained Br ALFRED P. MORGAN One of the most complete and comprehen- sive treatises on the subject ever published. A study of its pages will enable one to master all the details of the wireless trans- mission of messages. The author explains in simple language the theory and practice of wireless telegraphy and telephony. 154 pages, 156 engravings PRICE flM Design Data for Radio Transmitters and Receivers By M. B. SLEEPER The only book that fives tables and data for designing, receiving and transmitting apparatus so that you need no knowledge of mathematics. It's the first book a be- ginner buys after he has learned the use of his phone receiver PRICE_7Sc Construction of Radiophone and Telegraph Receivers for Beginners By M. B. SLEEPER The man who wants to feel the real thrill pf accomplishment, and who is not satisfied in the merely making use of what others have done for him, builds his own radio apparatus. Radio men can follow the data in "Radio Phone and Telegraph Receivers" with full confidence, because each piece of apparatus described was first made, tested and found efficient before the final design was accepted. Special receivers, both crys- tal and audion, are shown in detail. Regen- erative circuits as well as audio and radio frequency amplifiers are described with clear photos, diagrams, and working draw- ings prepared especially for the novice and the man who wants to receive the radio telephone broadcast. A special feature is the phonograph type radio set and the loud speaker. Fully illustrated .PRICE 7Se. The Radio Experimenter's Hand- book Br M. B. SLEEPER Throughout the preparation of this book, one purpose was kept in mind— Answer the Practical Questions of the "Novice," of the "Beginner, and the more advanced "Stu- dent." This book will help in the selection or construction of simple apparatus for the transmission and reception of radio tele- graph and telephone signals. In the chap- ters on radio receivers the simplest crystal, the simple audion, and the regenerative types are described in quite some detail. The question of antennas, both for* trans- mitting and receiving, are taken up. A good many helpful suggestions are given which will be of considerable aid to the experi- menter. 16 chapters. Fully illustrated. PRICE S1.M The A B C of Vacuum Tubes Used in Radio Reception By E. H. LEWIS Assoc. I. R, E., and Radio Instructor Written particularly for the person who "knows nothing about radio," but who would like to gain an understanding of the elementary principles of operation of vac- uum tubes and various circuits in which they are used for the reception of radio- telegraph signals and radio- telephone music and speech. Illustrated PRICE HJ> Books on Electricity practical kinds re- ast tanas, sees nils that win t familiar New Ba- ll. struct a Fifty Watt Dynamo. By ARTHUR J. WEED. A practical treatise showing In detail the construction ef a small dynamo or motor, the entire machine work ef which can be done on small foot lathe. Dimen- sioned working drawings arc given for each place of machine work, and each operation Is clearly described. This machine, when used as s dynamo, has an output of fifty watts; when used as a motor It will drive a small drill press or laths. It can be used to drive a sewing machine on any and all ordinary work. The book Is Illus- trated with more than elrty original engravings showing the actual construction of the different parts. Plies. II. M E7" Any of These Book* Sent Prepaid on Receipt of Price. The 11 Books for $10.00, to One or Different Addresses. address THE COLUMBIA PRINT ROOM 326, NO. 1493 BROADWAY, NEW YORK Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered as second-class matter, March 28, 1922, at the Poat Office at New York, N. Y., tinder the Act of March 3, 1879.] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publication* Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 479*. VoL II, No. 19. Whole No. 45 February 3, 1923 15c per copy, $6.80 a year Most Up-to-Date Radio Room on S. S. "Resolute 55 IN this elaborate radio room of S. S. Resolute, mentioned on the front page of this issue, Chief Operator Nelson J. Kearny is seen operating the spark set. The antenna is switched from receiving to trans- mission by means of a change-over switch, controlled from the operating table by means of chains. This allows the switch proper to be kept out of the way on the roof of the operating room. There are two switch-boards, one controlling the large set, which is supplied with current from the ship's generating set, and the other by die auxiliary set, worked from the storage batteries. This is necessary on all ships, as the law compels ship stations to embody an auxiliary set in their equipment, to be used in case of trouble with the ship current, which normally supplies the larger set. Directly under the larger switch- board, on the right, will be seen the telephone, by means of which the captain, or the man in charge of the bridge, can speak directly to the operator. Although the average ship now embodies a telephone exchange, similar to that in a large hotel, the tele- phone seen on the wall is directly con- nected so that there will be no delay in communication with the operator. It will be noticed that the receiver takes up only about one-quarter of the space generally used, the most space being allotted to the transmitting apparatus. As mentioned on the front page of this issue, this receiving apparatus, being compact, and at the same time very flexible as to wave- length, takes up little room. Many people have heard it said that the radio room is really the "heart of the ship," but they do not understand how true this is. With- out the radio room on board the captain would be put entirely at a dis- advantage. He would not be able to keep in touch with the ships in the By Harold Day (C. Kadel & Herbert) The interior of the S. S. Resolute's radio room. The extreme neatness and compactness of this apparatus are in direct contrast to the old time ship stations. The operator has plenty of room. vast body of ocean surrounding him, he would not receive the weather fore- cast or the position of various wrecks, which are a menace to all vessels. Taken all in all, he has become so accustomed to relying on radio that when the set is out of commission, be it only a short space of time, he gen- erally is a very worried man. Take for instance the ship that is nearing land in a dense fog. Before radio came into use, there of course were not so many large vessels navi- gating the seas at the one time. Now, the vessels get their bearings any time of the day and night by means of the stations located around the large har- bors, which, by means of "direction finders" can tell the captain his exact position, within two minutes after the signals have been heard by the land direction finder station. It therefore places a great deal of responsibility both on the radio oper- ator and the apparatus he is handling. For that reason, on all the big trans- oceanic liners, they have several expert operators, all of whom know how to take care of all the apparatus. You can see that radio is, then, as important to the captain of a ship as it is to the passengers. Many do not know that the little newspaper pub- lished on board a modern liner gets its information from the land stations that supply the service to the ships. Many people, especially those who have traveled over the seas numerous times, have become so accustomed to reading the bulletins and newspaper that they would be lost without them. Consider, also, the fact that serious accidents may happen aboard ship, which need the immediate attention of a medical man or surgeon. The cap- tain gets in touch with a ship in the vicinity, tells the symptoms, or accident, and the doctor in attendance, though he be miles away, diagnoses the illness, or advises treatment. Digitized by Google

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4 RADIO WORLD Radio Golf at 3,576 Miles an Hour FOR those amateurs who try to get the most out of their re- ceivers this new radio game will provide a means of keeping track of their achievements. It is said to have originated in Cuba, but it has taken a firm hold in the United States wher- ever it has been introduced. New Eng- land seems to have heard of it first, and a "DX nite owl" in Needham, Massachusetts, asserts that at present he is the champion radio golfer of the United States. His record for six hours and twenty minutes of play is 22,672 miles, or an average score of 3,576 miles per hour. To date this is the high score-card of all radio golfers, but it is not an unbeatable one. To play the game the radio amateur needs no equipment other than his usual receiving apparatus, with the possible addition of a pad, a pencil, and a watch. He starts at a certain hour, tunes in on a station and stays there just long enough to hear the announcer give the call letters and location of the broadcaster. This is the radio golfer's first hole. He jots the call letters, location, time of recep- tion, etc., on the pad, leaving a vacant column at the extreme right to be filled in later. With the first "hole" made he tees off for the second, and so on until the hour or hours of play are over. Then he counts up the number of By Arthur S. Gordon different stations brought in. No broadcasting station may be listed twice. With a map the radio golfer then proceeds to figure out how far away from the home "green" his various "shots" landed. In each case the mileage is entered in the right-hand column and added up to a grand total. In this way the course of the radio golfer is laid out over a broad section of the country, and in all directions of the compass. The idea is to tune in and identify as many different stations as possible during a limited period of play. It is important that a station be identified by its own announcer before the golfer drives off for the next. It is also desirable that the stations be as dis- tant as possible, for DX work is the factor which runs up the score. In this respect the play of radio golfers will differ. Some will prefer to bring in local stations in rapid succession, while others will reach out for the more difficult "drives" in an attempt to make distance all at once. Some may even develop a highly original technique. An hour or so of play will convince the radio amateur that radio golf is a fascinating game with all kinds of amusing and interesting possibilities. Situations will come up calling for quick decisions, demanding the exer- cise of discretion. Suppose, for ex- ample, that you are tuning for a New Anti-Noise Transmitter New type of transmitter developed for use in airplanes and other places where there Is a crest amount of external noise. The transmitter fits over the operator's head, beta* held in place by cotton webbing-, with rubber side pieces to press it firmly against the cheeks of the person wearing it without causing any annoyance. The transmitter proper is then against the lips of the operator. Design of Gstf Scars Card station which refuses to come in very clearly. Because of this difficulty yon have a suspicion that it is a distant outfit, therefore you hang on for the call letters. At the end of a long selec- tion, one that might have been enter- taining but for the fact that you were interested in something else just then, you wait anxiously for the call letters. Instead of giving them, as it should do, this particular station begins another selection, as many stations do at the present time, which prom- ises to be as long as the preceding one. What to do ? Hang on, or tune in for somebody else? Either procedure might be fatal to the final score. Most radio amateurs know how difficult it is to identify a half-missing station, and all of us have experienced a freaky and mysterious "shut-down." These possibilities are only a few of die points which make radio golf more interesting than it otherwise would be. The rules of the game are simple. Each player must agree to be fair and honorable in keeping his own score. A large map should be used — the one published in Radio World for May 20 is suited exactly — and the distances taken off carefully with a ruler or pair of dividers. Two hours is the official time limit, but if an amateur wishes to extend the period of play he may do so at his own risk. The DX amateur who "plays golf may now reduce his achievements to an hourly average in miles, which may be compared at a glance to the average of any other amateur. Play golf until you make what you please to call your "high score" card. Then submit it to the editor of Radio World for pos- sible publication. Watch the DX columns for the golf cards of other amateurs, and fill one out for yourself as soon as you can. Digitized by Google

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RADIO WORLD 5 Twenty-seven Stations May Be Abandoned for Good of Service WASHINGTON, D. C — The abandonment or transfer of twenty-seven minor naval radio and compass stations has recently been recommended by the Special Naval Board on Shore Stations, headed by Rear-Admiral Hugh Rod- man, and the recommendation for- warded to Congress by Secretary Denby with his approval. Disposal of these useless radio shore stations should make for naval sea efficiency. Communication experts of the navy believe that when they are closed com- mercial interests which they now serve will immediately establish new pub- lic stations equipped with modern apparatus, and that this will guarantee better service to the public and not in- terfere with broadcasting. Already die old Miami station is leased to a commercial company, which plans complete new equipment. Most of the old stations were unnecessary from a marine point of view, and the navy could not afford to continue their operation. Many of the radio trans- mitting stations recommended for the scrap heap were equipped with old spark sets, which interfered with tele- phonic broadcasting. Some of them had been maintained at a cost ten times the return since the war because no local public radio service facilities By Carl H. Butman were available at the time. All the high-powered naval radio stations, such as Arlington, Annapolis, Porto Rico, Canal Zone, Honolulu, Guam, and certain ones in Alaska, will be retained, as well as the semi-high- powered stations in the navy yards at the twelve important naval bases, and a number of minor stations now in use. Today there are 65 traffic stations and 33 compass stations in operation, requiring a personnel of 70 officers and 1,257 men. The elimination of 27 would leave 71 active stations, suffi- cient to meet the navy's needs ashore. The board recommends that 8 radio stations on the Great Lakes and those at Buffalo and Cleveland be abandoned or turned over to the army for opera- tion. Nine, located at Baltimore, Mobile, Miami and St. Petersburg, Grand Isle, Louisiana; Port Arthur, Seattle, Navassa Isle, West Indies, and Managua, Nicaragua, will probably be discontinued and abandoned. Radio compass stations at Detour Pass, White Fish Point, and Grand Morais, Michigan, are recommended for trans- fer to another government department or. abandoned. The sites of two old and unused radio stations at Siascon- sett and South Wellfleet, Massa- chusetts, are also recommended for disposal. Some of them might be operated by the navy if commercial and shipping interests would meet the cost of maintenance. Commenting on the recommenda- tions made the report of the committee states in part: "Radio communication is of para- mount importance to the fleet. The maintenance of a complete trans-ocean and coastwise system of radio com- munication by the Navy Department is necessary for the efficient management and operation of the fleets of the United States in peace and war. The control of various independent opera- tions can, through it, be more closely associated and made to conform with the general plan of action. Efficient radio service provides the means to obtain and disseminate information, and gives a nation that most important of all war assets — the power to strike hard with its fighting force. In time of peace efficient radio service is also essential to commerce. Superiority in this service by the navy is a factor of the same order of importance as superiority in number or types or in the trained officiency of ships. The Naval Radio System is an integral part of the navy. It must be maintained and operated during peace in such a way as to be of the greatest value in time of national emergency." Listening in Through Apartment House Walls Kadel & Herbert) The latest method of letting your sweetheart "listen in." This enthusiastic fan, by running a hose through the ments, lets Us fiancee listen In while comfortably enjoying the privacy of her boudoir. He uses a large hose, one end being Inserted in the loud speaker of his set, the other in the loud speaker in the to the adjoining i to that in a n Digitized by Google

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6 RADIO WORLD "Wired Wireless" Insures Secrecy in Sending Radio Messages (C. Underwood & Underwood) The small generators in the lower left-hand side of photograph supply the necessary plate current. THE latest improvements in the radio field have mystified a few and have caused others to raise their eyebrows and exclaim, "Well, I never!" This is probably the first published photograph show- ing the invention of Major General George O. Squire, the head of the signal corps of the United States Army. Major Squire calls his in- vention "wired wireless," because it does not depend on ether waves for the transmission of the modu- lated waves. Transmission may be accomplished by using any wires, high tension or telegraph lines, for the propagation of the signals. In the first actual demonstration of his invention, Major Squire used the apparatus shown in the picture, and the high-tension lines that radiate from the sub-station of the Poto- mac Electric Power Company, in Georgetown, and his message was received at the Bureau of Standards Building, over five miles distant. This new system of transmitting speech has countless advantages over the present method, most of which is its absolute directional ef- fect. A message started over a cer- tain line will follow only the direc- tion of that line, and will be heard only by people having apparatus and using that line for the purpose. Of course, this increases the secrecy of all messages transmitted by the new system. Every word spoken into a microphone at the present time, using the radio apparatus now in vogue, radiates in circles, and is audible to anyone who has a receiv- ing apparatus at any point of the compass. Major Squire has been experi- menting with the new method for many months, and has finally got it to a point of perfection. The photograph shows the battery of tubes that were used, as well as the motor generators used to generate the high current to supply the plate. The necessary condensers are seen resting on trie wooden table, under which are located the various con- trols needed in handling the high currents used. In order that the high tension, which is a very dangerous thing to experiment with if you don't under- stand it, may not back up and in- jure either the operator or the lis- (Continued on page 7) (C. Fnoto News; Transmitter proper with cover off. The apparatus is automatically shut off, when the cover is shut down. This is done to remove any UabiSty of danger to human life. Digitized by Google

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RADIO WORLD 7 Secretary of War Weeks Deplores Action in Harbord Case THE War Department has issued an official statement on the amendment to the army bill adopted by the House of Representa- tives for the purpose of depriving General Harbord, president of the Ra- dio Corporation of America, of retired pay. In this statement Secretary Weeks says officially: "It is most regrettable from the standpoint of the War Department and the public service that the House of Representatives adopted an amendment to the Army Bill which, in effect, takes from General Harbord, until recently Deputy Chief of Staff, his retired pay because he has become president of the Radio Corporation of America. The reason given for this action is that he has been employed by the Company for the purpose of obtaining more busi- ness from the Government than the Company could otherwise hope to se- cure. This is an insult to General Har- bord and to the Government itself. "For nearly forty years General Harbord has been faithfully and effi- ciently serving the Government and, regardless of what position he may oc- cupy in civil life, the best interests of his government will be his chief con- cern. Any inference to the contrary reflects on the person making it. As a matter of fact, the government's bus- iness with the Radio Corporation is inconsequential. At the present time there is no contract, and, generally speaking, purchases of radio equip- ment, which are of small moment in total amount, are made from the manu- facturers. But there is a much broader question involved in the action taken by the House. "General Harbord, the son of a western farmer, enlisted in the army. Starting his military career as a pri- vate, at the beginning of the World War, at the age of fifty, he held the rank of major. While his rank was not high, he had already impressed himself upon the War Department and his associates in the army to such a de- gree that he was made Chief of Staff of the American Expeditionary Forces. He went from that position to the com- mand of the Second Division, one of the most conspicuous fighting divisions in the army. He commanded this divi- sion during the Marne-Vesle campaign. Things were not going satisfactorily in the service of supply and he was trans- ferred, greatly to his regret, to the head of that service, a position of enormous responsibility and of the greatest importance to the army. He so reorganized and conducted that service that he brought to himself not only the plaudits of his associates in the army, but attracted the attention of men of importance in civilian life who were temporarily serving the gov- ernment in Europe; in fact, so extra- ordinary were his services and organiz- ing ability that they have occasioned continual commendation from civilians since the War, and it was because of this capacity that he was called to the presidency of the Radio Corporation, as the most competent available man for that particular service in the United States. "The development of the radio is of vast public importance and there is, therefore, a public reason why he should accept and fill his present posi- tion, retaining his place on the retired list of the army so that he will be avail- able for service in an emergency. If a British officer, French officer, or an officer of any other nation had per- formed for his government the service rendered by General Harbord, instead of having this stigma attached to him, that is, the inference that he is dishon- est— not to mention taking away his retired pay — he would have been given honors of very important character and certainly in the case of Great Britain, a large honorarium as well. I do not believe the people of this country wish its great defenders treated in such a shameful way, and I should think Gen- eral Harbord would feel that a coun- try that would tamely submit to such treatment of one of its officers was hardly worth serving. He will cer- tainly feel a sense of injustice which time can never efface." Secretary Weeks, according to the New York "Times," was recently ad- vised by the Radio Corporation that service to the government would be suspended if the legislation goes through. (Continued from preceding page) tener, there are necessary many banks of similar condenser and pro- tective devices. High tension, when out of control, has been known to jump many feet of intervening space seeking a ground, and there- fore it is absolutely necessary that all possible care be taken with, ex- periments. In order to insure this the lines were all looked over care- fully, to make sure that no one as- sociated with the experiment be hurt. The second photograph shows the cabinet containing the apparatus. It will be noticed at once that this bears no similarity in appearance to the present transmitting apparatus used for radiotelephony. Particular notice is called to the fact that all the controlling switches have fuses, and the entire cabinet is protected with a metal cover which automati- cally shuts off all the apparatus the moment the cover is let down. This absolutely prevents any disastrous results from the apparatus being left in operation when the operator is not present. These experiments have been car- ried on with utmost secrecy, and with the idea in mind of relieving the congestion, which is at present so noticeable in the air. When they are finally perfected, it is expected that the present system of broad- casting will be abandoned, in favor of the more efficient one. This, how- ever, is but a supposition on the part of the writer, and only time will tell. To realize the congestion in the ether, it is only necessary to listen in some evening, and realize how many hundred radiophone and tele- graph stations are operating at once, each one supreme in its own par- ticular district. Of course, this causes a great deal of interference, which is particularly annoying when more than one station is operating on one wave at the same time in very nearly the same district. Radio Exhibit in Kansas City ELEVEN jobbers contributed to the success of the radio show held in Kansas City from January 18 to 20. Eight thousand people attended the show, 300 of whom were children. Two local stations broadcasted from the exhibition room. Crystal, tube, and bulb sets were shown. The show was held in the ballroom of the Hotel Muehlebach. Radk> World, 52 issaes, $0.00. Subscribe (Erect or through yam now* dealer. $6.00 a year, $3.00 as months, $1 JO three months. RaaW World, 1493 Broadway, N. Y. C Digitized by Google

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s RADIO WORLD Various Filament Resistances and How to Make Them AMONG the various accessories required by the experimenter to build his receiving set — one that he can turn out easily — is the fila- ment rheostat. Quite suitable rheo- stats are on sale for several dollars, but an excellent pattern may be made at home much more cheaply that will be equal to the best of the ready-made apparatus now on the market. From the various known models I shall first describe the simpler one, which I will call the standard type. It is an easy matter to build it as it requires but a few feet of resistance wire, a spindle, a knob, some nuts, a bit of brass, and a little cardboard. To make this rheo- stat first get a convenient length of resistance wire. About five feet will do, according to its gauge. No. 25 S.-W.-G. is a suitable size, but other gauges will suit as well, provided the total resistance is about six ohms. This is a good average value, usually adopted to control from one to three bulbs. The former, oh which the wire is to be wound, is simple to make. With a pair of compasses first lay out two concentric circles on a piece of stout cardboard. The larger circle must be 3 inches in diameter, while the smaller one is but V/2 inches. Next, a little to one side, on the same sheet, lay out two further circles, the outer circumference having a diameter of 2}i inches and the inner one \}£ inches. Make another set of two con- centric circles of the latter dimensions. Now cut out the three pieces with a pair of scissors according to Figures 1 and 2. Take the larger piece (1) and glue one of the smaller ones (2) to each side, and give the whole a coat of shellac. When finished it resembles a horseshoe. When quite dry the wire may be wound upon it. This winding must be made tightly and very evenly, taking care to space each turn regularly. The wire is next fastened at both ends (Figure 4). Any regular switch may be used, but as it is in- tended to hook up the "horseshoe" on the back of a panel a bushing for the spindle will be found useful, though not indispensable. A rod is now fitted in front of the panel; a knob and its pointer is screwed on the spindle, and the sliding blade is secured at the other end of the threaded rod. (See Figures 4 and 5.) The "off" point is obtained when the slider leaves the wire. This very common form of rheostat is all that is needed with most hard tubes. But in order to get the best By Marius Thouvais Secretary of Radio Club of Coiogm results, particularly with certain kinds of "soft" audions used as detectors, it sometimes is required to have a very critical regulation of the filament potential, so a vernier adjustment is really useful. A good method of add- ing a vernier control to a regular rheo- stat is shown in Figure 6, where a second ebonite knob 4s fitted below the main handle. The spindle of this second knob holds another blade that slides over a single loop of resisting wire, this small arrangement being put in series with the main resistance. This service is all right when there is plenty of room on the panel ; but that is not always the case. In most case's the space is very limited. When this is so it is best to take a hollow spindle for the main resistance. A light, threaded rod passes through the main spindle — a small knob at one end, a sliding blade at the other — making con- tact over the loop of resistance wire, as shown in Figures 7 and 8. Other very convenient and rather newer patterns may now be described. Like the first three, they are simple to make, and their cost is only a matter of a few cents. All of the four or five types I will describe give an ex- tremely fine adjustment throughout their range, entirely doing away with the necessity of a further vernier. The pattern which is shown in Figures 10 and 11 requires a sort of drum ( Figure 9) , which may be made either of hard wood turned on the lathe or with any molded insulating material. A convenient size for this drum is 2 inches in diameter and 1 inch in length. This, when completed, must be generously brushed with shellac varnish before winding. Starting from a point of the drum wind the wire regularly and very tightly in spiral over the circum- ference, spacing the turns regularly. A second coat of thick varnish may be given after winding so as to strengthen the whole and firmly hold the wire down in its place, for it would be likely to sag under the rubbing of the blade if it were not strongly fastened to the former. Three holes are next bored, as shown in Figure 9, the central one to pass through the spindle ; the other two to fit the drum behind the panel by means of two small screws. The sliding blade must be about 2 inches in length. It is bent, as shown in Figure 11, and fitted, as usual, at the end of the spindle between two nuts. At the beginning of the spiral, behind the maximum resistance point, the rubbing blade finds an "off' position when leaving the wire. At the other end of the spiral the resistance is nil, yet the variation of resistance is very regular, and as slow as desired throughout the range covered. With this kind of rheostat a bushing for the spindle is really useful to improve the sliding of the blade over the wire, which must be, of course, as smooth as possible. On the other hand, a dial is no longer of use here, and the stand- ard ebonite knob, without pointer, is all that is necessary. Another new form of continuously variable resistance is shown in Figure 12. A springy resistance wire is coiled into a spiral around a brass spindle — a threaded rod, at the-end of which it is fastened between a set of nuts as usual. The construction of this latter pattern is still more simple than the others previously described. Its work- ing is easy to understand. When the wire is entirely unwound the resistance is maximum, as the current is com- pelled to flow throughout its length. But as soon as we turn the knob to the right the wire winds itself around the threaded rod, shorting to the conduc- tive body of the spindle, slowly and continuously lowering the resistance till zero is reached. The coil is entirely wound tightly around its spindle. This rheostat, which is certainly the simplest of all, is, perhaps, among the best. It has the advantage of taking very little space on a panel, and there- fore will appeal to many experi- menters. But its main and, doubtless, only disadvantage is that it has no "off" position, necessitating a separate switch. Fortunately there is a possi- bility of doing away with that annoy- ing switch, but the mounting then becomes a little more intricate. Figure 13 shows how to get thf very desirable "off" point. Here, as it may be seen, the contact is not taken directly from the spindle. This brass rod is passed through an ebonite, or waxed, cardboard tube, which insulates it from further tubing — a brass tube— which becomes the "shorting" contact. This is what provides the switching arrangement so greatly desired. This is hew it works : When turn- ing the knob to the left the spiral un- winds regularly, and soon after reach- ing the maximum resistance the wire swerves from the brass tube, breaking the circuit. Another class of filament (Continued on page 10) Digitized by Google

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks YTfHAT is meant by the term I/Mr hetrodyne as related to radio? This is a method of receiv ing undamped (C. W.) oscillations by making them interact with other locally produced, sustained oscillations. They are generally of slightly different fre- quency and greater amplitude, causing a beat note between the two circuits, due to the slightly different frequency in each circuit. This makes the un- damped oscillations audible, but is not much used owing to the commoner and easier method of regeneration. * * * What is the function of the tickler coil in a feed-back circuit? A tickler coil, through its' ability to transfer part of the energy of the oscillating current in the plate circuit set up by the incoming oscillations back into the grid circuit, produces oscillations of a beat frequency, and {Continued from page 9) regulator is based on quite a different principle. There is no longer a re- sistance wire in its construction. The variation of resistance is obtained through a screw-conductive material, the pressure of which may easily be varied, applied, or removed — quickly or slowly and progressively — by means of a milling screw. Figure 14 shows how such a re- sistance may be made simply with a pile of carbon discs, while Figure IS shows a rather more elaborate type, which embodies two piles of discs. In both patterns a large brass washer is put on either side of the carbon filler in order to make a positive contact. The pressure on the resisting material is continuously variable through the screw and its knob. Finally, there is a model which, although very similar to the preceding ones, embodies a somewhat different resisting material. Its resistance is made of powder — graphite powder or loose carbon grains — enclosed in a small cylindrical box. The only dis- advantage of this last type is that the powder tends to "keep crowded" when once compressed. To overcome this inconvenience a coil spring is put in the box in order to crumble the mass when the pressure is removed. also amplification, making undamped (C. W.) signals audible. * * * What are the advantages of an oscillating circuit over a straight detector circuit? 1. Owing to the fact that regenera- tion is possible with an oscillating cir- cuit a greater response may be had from the detector, due to self- amplification. 2. It makes undamped (C. W.) signals audible. 3. Sharper tuning is made possible. * * * What is the quickest way of telling the exact condition of your storage battery (charged or uncharged)? By the use of a hydrometer. * * * What is a hydrometer? A hydrometer consists of a glass tube containing a graduated scale with markings from 1.000 to 1.300. These markings are generally made on paper and inserted inside of the tube, which is small at the top and larger at the bottom, as shown in sketch. The larger part generally contains lead shot or some other heavy substance, which will cause it to remain upright in a solution. This smaller tube is generally placed in a larger tube having a sealed bottom, with a rubber tube projecting. At the top there is a syringe, which causes the solution to be tested to be drawn up in the larger tube, floating the smaller one. What is the advantage of a hydrometer? It allows a quick and accurate test Slmpla Sketch of ■ Hydrometer of the condition of the cell through the agency of the specific gravity of the battery solution, which is higher when the cell is charged than when discharged. * * * What is meant by specific gravity of a cell? By this we mean the weight of a volume of the electrolyte as compared to the weight of an equal amount of pure distilled water, taken as a stand- ard. A hydrometer will therefore show in the graduations how much heavier the electrolyte is than water. * * * What are three indications of a fully charged cell? Gassing (extensive bubbling) of the cell if the current charging the cell is small. Specific gravity as shown by a hydrometer as being 1.220 or greater. Voltage of 2.1 or higher as shown by a voltmeter. * * * Is a gassing cell a reliable indicator of a charged cell? A gassing cell is not always a reliable indicator of a fully charged cell on account of the fact that chemi- cal impurities sometimes get into the electrolyte, causing gas to rise when the cell is not fully charged. This does not always happen, but it is always best to check your cell through either the use of a voltmeter or a hydrometer in order to more accurately learn the condition of the charge. * * ♦ What main factor determines the capacity of a cell? The number of square feet of posi- tive plate surface (active) and the number of positive plates used in the cell. In general practice we allow from 6 to 8 amperes for each square foot of positive plate surface. * * * Why is it necessary to add water to a battery? Because of evaporation it is neces- sary to add water to keep the strength of the electrolyte constant. The acid does not evaporate, therefore it is not necessary to add any. It is a good plan to empty the entire solution occa- sionally, and to clean the jars with pure, distilled water before putting back clean electrolyte. THOUSANDS of radio beginners have come into the radio field since sum- mer. They will find "The Radio Primer," published weekly in RADIO WORLD, a regular source of instruction and aid. For this reason, RADIO WORLD will repub- lish, from time to time, tome of the valu- able primer articles that appeared in its early issues. These articles, by experts, contain a vast amount of radio informa- tion that cannot be duplicated. Every be- ginner will find them necessary to the building of sets and cooperative with the new material being printed weekly. Digitized by Google

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RADIO WORLD 11 Radio Development Is Rapid in Germany WHILE the activities of Eng- land, France and Holland in the field of radio have been concentrated since the war on the establishment of communica- tions with their dominions and col- onies, Germany, deprived of all over- seas possessions, has been building up within her own borders a system of radiotelegraph and radiotelephone stations that is second to none in the world, says W. T. Daugherty, assistant trade commissioner, in a report to the Department of Com- merce. The loss to Germany of her ocean cable system, built up at great cost during the fifteen years preced- ing the war, made her dependent on neighboring countries for all her international communication, ex- cept the portion that she could handle by radio. The logical result has been the increased use of high- power radio stations for overseas communications, especially to the United States. At present the central office of the Gosellschaft fur drahtlose Tele- graphie, located in the Oranienbur- gerstrasse, Berlin, controls the two great transmitting stations. Nauen and Eilvese, and the two receiving stations, Gelton and Hagen. Both the transmitting stations work on schedule, Nauen with New York, Moscow, Madrid, Rome and Bu- charest; and Eilvese with Rome and Madrid. Both have transatlantic press schedules as well. Extensive changes are now in progress at Nauen, says Mr. Daugh- erty, designed to increase its power and the flexibility of its operating plant. Separate antennas are being constructed^ for the American, the Asian, and African, and the two » European circuits; and a special ar- rangement is planned for the new Buenos Aires circuit which is to be opened to public correspondence within the next few months. The corresponding station at Monte Grande, near Buenos Aires, is to be maintained and operated by a com- bination of French, English, Ger- man and American radio companies. The German Post Office station at Koenigswusterhausen, near Ber- lin, transmits to Lpndon, Budapest, Sofia and Saraijevo, and its receiv- ing station at Zehlendorf makes up the return circuit. Norddeich, a coastal station used for hydro- graphic reports, shipping news and By John Kent weather reports, completes this group which is known as the Main Stations Group (Hauptfunkstellen). Although communication is main- tained with the foreign cities men- tioned, the Main Stations Group op- erates principally within Germany. The feeder stations of this system, or "leading stations" (Leitfunkstel- len) operate an interior service as subsidiaries of Koenigswusterhau- sen. The stations located at Dort- mund, Breslau, Duesseldorf, Frank- fort-on- the- Main, Hamburg, Han- over, Koenigsberg in Prussia and Munich are each equipped with two sending and two receiving installa- tions. Dortmund operates a spe- cial service to Rotterdam as well. "Simple stations" (Funkstellen) supplementing the feeder stations and equipped each with a single sending and receiving set, are lo- cated at Bremen, Darmstadt, Elbing, Friedrichshafen, Constance, Stettin, Nuernberg and Mainheim. Ship-to-shore stations are sixteen in number and were excepted from the system taken over by the Post Office Department in 1919. The distribution of the wireless news broadcast from the interior transmitting stations is effected by 75 receiving stations which have no transmitting sets. Similarly equip- ped stations receive weather reports in nine of the principal cities. Public wireless telephony was in- augurated in Germany on Septem- ber 1, 1922, the Post Office Depart- ment and the Express Service (Eildienst G.m.b.H.) uniting to es- tablish the service. Subscriptions, open to the public, are based on the extent of the service rendered, and the only additional cost is the in- stallation charge. The apparatus used may be em- ployed by either telegraphic or tele- phonic reception, vacuum tubes being supplied. In accordance with the distance from the broadcasting station, amplification in varying stages is provided. Koenigswusterhausen is the broadcasting station and subscribers to the service are now located in 176 cities and towns. The material furnished so far has been confined to economic news. Listening in on Europe IU Keystune View) Officers of the American Radio Relay Lmiw are here Man *-f ta amateurs who an permitted to transmit with high power through special privilege than by their rsapectivs governments. At the right of the phonograph Is Manum, president of the A. R. R. L. Seated next to him U F. H. Schnau, traffic aad aa the table fa) Kenneth B. Warner, secretary of the Digitized by Google

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12 RADIO WORLD White Radio Bill Recognizes Privileged Status of Amateurs By Washington R. Service WASHINGTON, D. C— Pro- ponents of the White Radio Bill, unanimously reported out by die House Committee last week without amendment, hope for its early passage. The bill requires licenses for all transmitting stations other than gov- ernmental stations, and all except governmenal operators. It directs the Secretary of Commerce to classify licensed stations and make rules and regulations for the prevention of in- terference. The President will assign wave-lengths to government stations. But when government stations, other than vessels at sea, are transmitting commercial messages they are subject to the regulations for commercial stations and traffic. Other features of the bill give the President enlarged authority over all radio stations in time of war, forbid aliens from owning radio stations in this country, restrain the transfer of licenses, limit their duration and pro- vide for revocation of licenses. The issuance of licenses rests with the dis- cretion of the Secretary of Commerce. Congressman White's pending bill recognizes the privileged status accorded to amateurs by the radio act of 1912. It strikes from existing law the words "200 meters," and provides that "the wave-lengths for amateurs shall not be less than 150 meters nor more than 275 meters." This change was desired by the amateurs, and has the approval of the conference and of the committee. The amateur is die only user of radio to whom a definite assignment of wave-length is made in the law itself. Other wave-lengths are allocated by the Secretary of Com- merce. The committee appreciates the value of the service which the amateur is rendering in the development of the art and in the training of skillful operators, and feels justified in con- tinuing special recognition. The Electrons Work in Radio By B. R. Cummings Radio Engineer, General Electric Company IN technical and semi-technical publica- tions reference is more and more fre- quently made to the electron, and it it the writer's object to point out some of its most unusual characteristics with the hope that those who take interest in the many developments of science will find an in- centive to investigate further this fascinat- ing branch of the electrical art The electron is denned as the unit charge of negative electricity. It plays a most important part in the composition of all matter. Those of us who have studied chemistry, even in its most elementary form, know that all materials are composed of atoms, the atom being defined as the smallest particle of any material which retains the characteristics of the material ; so that there are atoms of iron, of copper, of oxygen, and of all the elements. For many years it was believed that the atom was indivisible, and that it itself was the smallest possible subdivision of matter. More recently it has been discovered, how- ever, that the atom is composed of units, the number of which depend upon the material of the atom. It has been shown that all atoms consist of a. nucleus, which is called the proton, which is in reality a positive charge of elec- tricity. Surrounding this nucleus are electrons, the number and arrangement of which depend upon the material of the atom. The structure of the atom is fre- quently referred to as a constellation, and may be pictured as resembling our solar system, the positive nucleus representing the sun, and the electrons surrounding it the planets. The arrangement of electrons about the positive nucleus hat been the subject of much investigation, and, while there are differences of opinion as to their specific number and exact arrangement, it is com- monly agreed that one series of atoms, representing a number of materials, hat from one to eight electrons surrounding the nucleus in what is referred to as the first shell, all of the electrons lying on the surface of a sphere. The atoms of the next series of elements have, in addition to the first shell of electrons, a second shell, which includes from one to eight electrons, also lying on the surface of a concentric sphere. Another series includes a third shell and still another a fourth shell, so that the number of electrons associated with the positive nucleus varies from one in the hydrogen atom to as many as a hundred or more in the atom of the heaviest metals. It is contended by some scientists that the electrons have definite orbits about the positive nucleus, which still further brings the modern conception of the ultimate form of matter into a system similar to our solar system. Quite recently it has been shown that the positive nucleus itself is very probably complex and may consist of a combination of two or more units. The probable forma- tion of this structure, however, is as yet unknown. From the foregoing it is apparent that all matter consists, in the ultimate analysis, of the same thing; that is, of positive and negative electricity, and that different mate- rials, as we know them, have their varying characteristics, due to differences in the arrangement and number of electrons in their atomic structure. In any material there is practically an infinite number of atoms, associated with which there is a still greater number of electrons. These atoms are in constant motion except when the material is at a temperature corresponding to absolute zero, and while in such motion they collide with each other continuously. Such collisions result in electrons being freed from many of the atoms, so that all materials include a number of so-called free-electrons, which are moving back and forth in the material at extremely high speeds. These are the carriers of electricity in any material; in fact, they themselves are electricity. Mate- rials which we know as good conductors of electricity, such as copper, have a com- paratively great number of free-electrons. Those materials which we know as in- sulators, such as glass and porcelain, have a very small number. When an electric current flows there is a progression of the free-electrons through the material making up the circuit. If the temperature of the material is in- creased the speed of the electrons is increased until, if the temperature is made sufficiently high, as in the filament of a receiving vacuum tube, the electrons break through the surface of the material into the surrounding space. The characteristics of the electron are extremely interesting. These are not assumed, but have been established by the most painstaking research. The electron it so small that we can never hope to see it directly, for it is much smaller than the shortest wave-length of light, and therefore is incapable of reflecting light. Itt diameter, when expressed as a fraction of an inch, it so small as to be meaningless; but some conception of its size can be had from the following : If a drop of water, which consists of hydrogen and oxygen atoms, and therefore includes a great number of electrons, were magnified to the size of the earth, and all of the electrons associated with it majntfif^ in the same proportion, even then each electron would appear only as large as a grain of sand. The third characteristic of electrons it the velocity of its travel. Those of us who use vacuum tubes in our receiving equip- ments know that electrons are given off at the filament, travel across the intervening space between the filament and the plate, and finally enter the plate and then travel through the conductors of the circuit The current in the vacuum tube is composed of electrons. It is referred to as the electron current, or, to differentiate it from currents flowing in conductors, which are also elec- tron currents, it is more specifically re- ferred to as a thermionic current When electrons leave the filament of a vacuum tube and start their travel toward the plate they are moving at a speed of approxi- mately 50,000 miles a second. Digitized by Google

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RADIO WORLD 13 Accomplished on Indoor Aerial •tattoo* aa an ax for THIS map shows the remark- able receiving record of an amateur in Washington, which will give the sceptics some- thing to "think about." All of the stations heard were oper- ated by amateurs, and according to the law an amateur is limited to low power. He is, therefore, to be commended because he uses just what he can, and sees that he uses it as efficiently as it is humanly possible. This is testified to by the fact that he has covered such re- markable distances. Many ama- teurs, who have good apparatus and plenty of resources at command, pay no attention to getting their station "up to tick," and are fully content to talk to the man five or ten miles away. A little time spent in carefully hooking up and read- justing their sets would really en- able them to accomplish wonders. To give an idea of the efficiency of the apparatus that must have been used by this Washington ama- teur, consider the fact that the sta- tions recorded on the map were all heard on a set using three stages of radio-frequency amplification, and the electric light wires as an an- tenna, through the agency of a plug, sold for that purpose. By reference to the map it is easy to see that good reception was ac- hy Herbert Hoover. Jr, eon of the Secretary of three atepa of radie-fre qneacy. Thia will give aoaae of the DX boye ad maybe give theaa an Idea far chart*** etat tana. complished from all sections, north, south and west. There was no dis- tance to cover to the east toward the Atlantic Ocean. You will note that most of the reception was really accomplished over distances above three hundred miles. In these days, radio amateurs seem to be paying all their atten- tion to improving their receiving apparatus, and you do not hear much talk of the transmission end of the game. But you can sit back secure in the fact that for every improve- ment made in receiving equipment, someone is improving his transmit- ter. It is due to the untiring inter- est and efforts of the American amateurs that radio has reached the marvelous efficiency it has at the present day. Many a radio hero sits up night after night, working and thinking of the many ways in which he can improve his apparatus, and then putting his plans into action. When he does, there is generally something doing in the air besides a lot of noise, and nine times out of ten he will hang up another distance record. r>aari la c with shipa at eae, to furaiah them daily am, aa well aa wim the) feral the termlaue of the mad wtra UaUaa Bui— with ether It b> alee Digitized by Google

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14 RADIO WORLD Radiograms THE Netherland government has completed the new power- ful receiving and transmitting wireless telegraph station erected at Kootwyk for communication between Holland and her East Indian colonies. This station has been clearly heard in Java, a distance of 7,500 miles, and also in America. It is equipped with German apparatus and is said to have the same capacity as the Long Island station. * * * Patients in St. Luke's Hospital, on Morningside Heights in New York City, are no longer cut off from the outside world while they are ill or convalescing. A new radio service has been installed in the hospital's four large wards, the children's receiving ward and in some of the private rooms, and about one hundred patients are daily enabled to listen in on varied pro- grams of grand opera, popular songs, band concerts, selec- tions by famous orchestras and recitations. On Sundays organ music and the services of St. Thomas' Protestant Episcopal Church, of New York City, are provided. Each patient is per- mitted to listen for from twenty minutes to half an hour, when the radio receiver is passed to some one else. St. Luke's receives its program from Station WEAF, Ameri- can Telephone and Telegraph Company; Station WOR, of L Bamberger & Co., Newark, and Station WJZ, of the Westing- house Electric Company, Newark. * * • Homesick fowls, attending the annual National Poultry Show, which ran last week at Madison Square Garden in New York City, were able to communicate by radio with relatives and friends at home. The awards in the show were broadcast every evening and prize winning fowls were permitted to send messages back to the farm. An effort was made to broadcast the general hubbub made by the thousands of fowls tempo- rarily inhabiting the Garden. * * * That radio communication may be of great value in mine rescue work has been shown by experiments recently con- ducted by the Bureau of Mines, working with Westinghouse engineers, at Bruceton, Pennsylvania. Signals were distinctly heard through 50 feet of coal strata, audibility falling off rapidly as distance was increased. With a receiving instrument 100 feet underground signals from a station 18 miles distant were distinctly heard, but an iron pipe, containing electric light wires, which extended therefrom through the mine, assisted greatly in the reception. The transmitter used sent out con- tinuous waves of 200 to 300-meter wave length. The best re- sults were obtained from vertical antennae, horizontal ones giving practically no reception. A loop of a single turn was used with fair results. The strata at the experimental mine lie almost horizontal; the mine is a comparatively dry mine, but the overburden is damp. Further experiments are to be made along thU line. * * * Owners of vessels equipped with wireless apparatus, com- panies operating and controlling the apparatus, and radio inspectors are advised to see that all ship stations are properly licensed at required by Section 2 of the Act of August 13, 1912, in that the correct ownership of the vessel and the ownership of the station are shown in the license. When a vessel changes ownership the old ship station license should be surrendered, notwithstanding the fact that the period for which the station was licensed may not have expired, and a new license procured showing the new owner- ship and any other changes in the data required in the license. It has been reported to the bureau that a number of vessels, especially vessels sold by the U. S. Shipping Board to private owners, are violating the law in this respect. » * * Radio impulses from a radio receiving sat may be trans- mitted through the air for a considerable distance from the machine and then be picked up and carried by an ungrounded wire. This interesting discovery has been made by Robert Hilliard, the hydraulic engineer in charge of the tank equipment used in "Better Times," at the Hippodrome in New York City. A New Amplifying Receiver By Frederic J. Rumford, A.LE.E. THE latest invention in amplifying receivers is the work of an X-ray expert, Dr. Frances Le Roy Satterlee, of Flushing, L. I. This invention was called to the attention of Major-Gen- eral George O. Squier, chief officer of the Signal Corps of the United States Army by the inventor. General Squier, after several hours of study and ex- periment has given it the name of "in- ductive amplifying receiver." A test made of this new receiver by army experts at Ford Wood has brought out the following facts. On receiving the radio broadcasting of WJZ, which is about twelve miles away, using this for a test station, the experts obtained an audibility of 400 against 200, the latter obtained with the usual duo-lateral coils. On working out this test, the army experts say they were particularly impressed by the G.L t 6.C. Cr IMAWW sis Dr. F, La Roy Sattarlet's New Amplifying Circuit. comparative ease of manipulation and tuning, and also the freedom from all distortion. Tuning is done roughly by the man- ipulation of the two variable condens- ers C and CI ; tuning for finer recep- tion by changing the positions of these coils L, LI and L2. These coils are unusual, being wound in the form of flat spiral with litz wire. They are also said to have less distributed capacity than the usual honeycomb and duo-lateral coils, and lower high frequency resistance. The notable features of this receiver are: 1. Signals which are equal if not bet- ter than those received on an Arm- strong plain regenerative type. ,2. Absolutely no chances of oscilla- tion which will decrease any intetfer- ence with near-by receiving stations. 3. Very close and sharp tuning. 4. Very low cost of construction. The coils L, LI and L2 are similar in appearance to small phonograph records, disc type. L and L2 are piv- oted and move like the leaves of a book, while LI moves in slide fashion in and out between them. The other part of this circuit resembles an or- dinary non-regenerative receiver. Digitized by Google

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RADIO WORLD 15 Radio and the Woman By Crystal D. Tector 1HAVE just received a letter from a young woman, all the way up in the North Canadian Woods, and this is what she says: "We are snowed in pretty nearly seven to fourteen weeks of the year, and as daddy is a trapper I seldom get a chance to have any fun, except the weekly trip of the Padre, or probably some belated trapper, who will stop in for a few nights to get 'thawed out.' You can see what it means to me, having lived most all my fife in a large seminary, in Montreal. Last year daddy let me stay with one of the girls in Montreal, and the winter before I had a party of girls up here; but they all left early, because of the intense cold and hardships. Now that daddy has let me have a radio set, I don't have much trouble enjoying myself when the long nights come. 1 enjoy your articles, when I get the magazine, which is about every three months, because of the delayed mail, and I generally get aU the issues at once." This girl is very lucky. Can you imagine anything finer than those piney woods in the summer, and a beautiful cabin decked with furs, a radio set and a Radio World during the winter? • * * ALONG with everything else, I have received a notice through Friend Husband that I can take an examination to become a radio inspector. Imagine that) I will be kept busy, and F. H. will be kept hungry, if I accept his challenge— which I shan't • * * DO you notice that most of the popular musical comedies have a "radio" song or number? No wonder radio is so popular with the Tired Business Man. Friend Husband and I went to a widely advertised musical comedy the other evening, and one of the hits of the show was a number on radio. F. H. remarked that the prima donna's voice was wonderful, but I think that that little chorus dancer was much more interesting. • * * AVERY dear friend of mine received a letter from her son, away in a military school, who told her that he had "helped install the radio set." He seemed to be as proud of that as of the high percentages in his studies, and the fact that he stood second in the class. FRIEND HUSBAND came in the other night wearing a face as long as anything. "Humph I I don't think much of Mr. s views," he said. After a while, not getting any reply from me — because I know that if I show any curiosity when he U angry he will take it out on me for being "curious"— he brightened up and remarked: "Say, if that fellow would only read the White Bill he wouldn't need to argue so foolishly. Anybody with a grain of sense can understand it if he reads it. So long as it was only about the legal points I let it go, for when F. H. talks legalities he simply bewilders me, and I believe that "silence is golden." At such times he becomes a silver tongued orator and is likely to rave on all night * * * IT is interesting to listen in on some of the daily conversation in the cars and streets today. Most everyone is adapting the radio terms to their daily conversation. Just the other day, while on a shopping tour in New York, I overheard this con- versation between a pert flapper and her escort: "Well, talk about interference, when that OW starts to broadcast, everyone else has to pipe down. She started at the beginning of the din- ner and, honestly, she drowned us all out." "Oh, don't I know it Say, she is worse than WEAF when she starts. You can't even hear across the table when she opens up her transmitter. Somebody ought to tell her to decrease her decrement— her wave is too broad." "Well, Sheba, guess 111 duck. So long for a while. My boss is a bear for opening the program on time, and I have a terrible stack of accounts to enter." "So long, OM. C.U.L." I looked in surprise, but all the rest of the folks around didn't seem to even notice 'the new. language that was being used. • * * FRIEND husband gave me quite a surprise last evening when he broke the news that he intended taking a license. "What kind, auto, druggist, or marriage?" I asked. "Why, stupid, a radio license, of course. What do you think of that?" Well, all I can say, is that I see where F. H. has been bitten BAD by that insect named "Radio." He will probably never recover, but as it isn't fatal to anything except the wallet, "I don't-care. My Idea of a Radio Set By Henry N. Fullerton, M. D. for b.baTt 2o© oMm\ New hook-up for radio- frequency amplification. BEGINNING with a regenerative circuit using only a detector, I made hook-up using one, two, three, and four stages of audio-frequency amplification. Not being wholly satisfied with the results obtained, although I was get- ting as successful results as others with the same hook-ups, I then began experimenting with the non-regenera- tive class of circuits making use of radio-frequency. Beginning with one stage of radio-frequency and a detec- tor, I have used one, two and three stages of radio-frequency amplification ahead of .the detector, and, also, one and two stages of audio- frequency in combination with one, two, and three stages of radio-frequency amplifica- tion. With the radio-frequency type of receiver, I have had some remarkable results, receiving stations at a distance of 2,200 miles loud and clear. I have received concerts from Chicago, Daven- port, Iowa, and other distant places. Taking all phases into consideration, I think that a nonregenerative receiv- ing hook-up using one stage of radio- frequency detector and one stage of radio-frequency is about the ideal radio outfit. With this hook-up sig- nals are received of sufficient volume up to 1,000 miles and there is the ad- vantage of getting practically no inter- ference from tubes or other parts. In the set that I have been using, I utilize a vario-coupler and vari- ometer, believing that the basket type of weave adds to the efficiency of the apparatus. For the radio-frequency transformer, I use an Earla. For the audio-frequency transformer, a U-V 712. I enclose a diagram of the hook-up. I have received concerts and other broadcast programs from about sixty different stations, ranging from 300 to 2,200 miles. Digitized by Google

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RAD1U UUKLD Captions by Patrick Nichols A single- tube radio Mt which Dr. R. 3. Phssr. . Chicago surgeon, has devised and patented. This Ht works on a door-b<-U battery and B battery with very high aenaitivity and se- lectivity and ia used either with head phone* or horn, which ever way desired at the time! It can also be used with a storage battery (C. KadeJ and Herbert) On top of a London bos ceived in a m n two-tube po»- than la ex- -•hlclo. Your notice is called Of was given showing that radio could be ra- te the fact that both radio frequency and a the apparatus as shown takes up •» Idea, and waa carried out very a ifully. (C Kadel and Herbert)

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RADIO WORLD r >tographs "eek C. FraacU Jenkins, who U the Inventor of this apparatus for transmission of moving pictures vis radio. Mr. Jenkins predicts that within the next few years his invention is going to be as popular as the movies.** lea so j Senator, testing the radio set made by himself. The ardent radio fans through his and office girls lunch to the tune of instead of going out for their noon walk. The photo- ph shows how an enterprising employer has Installed radio set In his employ see rest room, for the purpose of ntertaining them while they are eating their luncheons. 5£ v, Louis Bamberger, well known merchant of Newark, New Jer- sey, who sailed on the S-S, Homeric Saturday, has Installed a powerful radio receiving out- fit in his stateroom, by means of which he will keep in con-

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18 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $15000 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 Radio Exports During November, 1922 According to Statement by Department of Commerce 7184 Telephone apparatus 7181 7182 including Radio and wire- Telegraph telephone less apparatus apparatus switchboards Countries Pounds Dollars Pounds Dollars Pounds Dollars Belgium 92 891 201 809 Denmark ... 160 1,361 France 217 1,018 134 738 Germany 1,700 875 Iceland and Faroe Islands 20 88 Netherlands 992 1,361 276 1,188 Norway 24 54 Spain , 81 93 110 284 Sweden 201 274 29 122 England 2,203 6,606 1,687 1,509 71,924 100,501 Canada— Maritime Provinces ... 419 1,542 7,094 1,484 622 672 Quebec and Ontario... 23,214 39,834 10,646 9,474 35,715 47,384 Prairie Provinces .... 8,690 16,273 92 91 1,782 3,859 Brit. Col. & Yukon. .. . 384 .627 137 603 ' - 737 1,372 Costa Rica 2 32 ... ... Guatemala ... 26 59 Honduras ... ... ... 5,607 4,076 Nigaragua 24 25 1,492 4,007 Panama 23 125 136 129 Salvador 123 384 Mexico , 76,670 12,998 3,692 2,683 7,432 3,352 Mkjuelon and St. Pierre Is ... ... ... 117 123 Newfoundland and Labrador ... 3,555 5,048 1,537 2,477 Bermuda ... 1,011 1,051 Jamaica ... 898 401 Trinidad and Tobago ... 700 466 Other Brit. West Indies 80 325 35 18 Cuba 11,199 24,586 261 585 17,127 23,008 Dominican Republic 51 48 221 1,184 Haiti ... ... ... 3 6 Virgin Islands of U. S 635 373 Argentina 18,158 71374 8 15 2,605 12,561 Brazil 7.53 4,199 546 6,000 7,912 30.140 Chile 788 1,951 746 1,462 Colombia ... 9,115 8,686 Ecuador 587 1,114 Peru 40 400 2,157 2,973 Uruguay 2,166 12,208 Venezuela 739 1,341 British India 15 34 Straits Settlements 43 81 China • 86 165 , 1,458 1,543 Hongkong 24 130 60 128 Japan 1,385 6,703 82 342 15,198 37,533 Philippine Islands 3,065 3,476 ... Australia 2,214 5,404 ' 11 204 7,338 19,000 British Oceania 50 45 New Zealand 4,886 9,011 11 177 3,788 2,260 British South Africa 40 224 51 70 Egypt 18 121 Total 159,958 223,180 27,862 34,615 200,562 318,336 SHIPMENTS FROM THE UNITED STATES TO NON-CONTIGUOUS TERRITORIES Telephones Non-contiguous territories Dollars Alaska 1,000 Hawaii 1,100 Porto Rico 55 COMPLETE YOUR FILES OF RADIO WORLD FOR 1922 mi Radio World are becoming (career all tba time. We Now 1 to date at ft Keen cento a copy. Any oeven ammbera RADIO WORLD, MIS Broadway, New York CHy New Firms and Corpora- tions (The Arms and corporations mentioned in these columns can be reached by communi- cating with the attorneys, whose address** vre given whenever possible.) Goodnow- Gardner Electrical Corporation, care of Good, Kimbrought ft Hutchinson, Boulder, Colo. John Barstow, Barstow't Radio Shop, Selwitz Block, 10 Pearl street. South Manchester, Coca. Clarence L. Carey, Haisley Bids., Lake Wales, Fla. Torrington Electric Company, Orpheum Bid*-., Wichita, Kan. Case, Manhattan, electrical business, £20,000: N. L Case, C G. A. Weiss. (Attorney, J. M. Detzen, 61 Broadway, New York.) Premo Electric Corp., Manhattan, $10,000; L. M. Fox, M. L. Gilman. (Attorney, B. Lewiusoo, 119 Nassau street. New York.) Vesey Electric Sales Corp., Manhattan, selling electric fixtures, $25,000: M. Gerst, L Bailey. (Attorney, N. Bolet, 55 Vesey street. New York.) Unit Radio Corp., Manhattan, supplies, $10,000; B. Katz, M. Julien, A. Zweekly. (Attorney, A. F. Karman, 116 Nassau street. New York.) J. C. Harding ft Co., Wilmington, Del;, electri- cal contracting, $20,000. (American Guaranty and Trust Co.) Proroethesus Electric Corp., Manhattan, $66,- 430; H. L. Herrick, F.'D. Hagan, J. Van Harder. (Attorneys, Davis, Symmes ft Schreiber, 55 Liberty street, New York City.) Excello Construction and Electric Co.. Man- hattan, $5,000; E. J. Dwyer, L. P. Wilkinson. (Attorney, P. A. Schmitt, 119 West 42d street, New York City.) Stuyvesant Electric Co., Manhattan, has in- creased capital stock from $10,000 to $50,000. Cosmo Electric Construction Company, Manhat- tan, $150,000; P. Aigddinger, J. Spitzer, C H. Pond. (Attorney, T. F. McMahon, 1400 Broadway, New York City.) Construction Materials Corp., Manhattan, elec- tricians, $10,000; E. C and A. M. Sargeant, W. Porter. (Attorney, E. P. Feely, 43 Broadway, New York City.) Radio Stocks Curb Market of the week ending January 20. Quotations from New York Times of January 22 : Sales High Low Last 7,300 Dublier Cond. and Radio S% 5 5K +M 300 Prima Radio Co 88 .87 .88 —.08 12,300 Radio Co. 3% Hi 3H 13,500 Radio Co. pf 394 31-16 3tf+116 Coming Events The editors of RADIO WORLD will •teams of all Ms* full ERMJ PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York CHy. Open from September, 1922, to May, 1923. SECOND DISTRICT RADIO CONVENTION, Hotel PemuylraaU, Hew York City, March 1. R and 3, 1923 FIRST UNIVERSAL EXPOSITION OF Of. VENTIONS AND PATENTS, Grand Central Pal- New York City, February 17 to a, SOUTH JERSEY'S FIRST RADIO- ELEC- TRICAL SHOW, Third Regiment Armory, Cam- len, N. J., February 5 to 10, inclusive. Western Electric Company- Post Gives Theatre Party THE Broadhurst Theatre in New York CJty was bought out for the night of January 23 by the Western Electric Company Post of the American Legion. The performance for the evening was "Whispering Wires." Digitized by Google

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RADIO - WORLD 19 Answers to Readers /~*1VE me any information you have on v_7 the use of the W -D 11 as a radio- fre- quency amplifier. I have inquired in several places, but no one seems to have any definite information. Are they inferior or superior to the 6-volt tubes for this purpose?— A. T. Bales, 501 Merchants Exchange, St. Lout'. These tubes cannot be used successfully as radio-frequency amplifiers. The best tubes for this purpose are the ones you mention in your letter or the V-T 2, Western Electric. * * * Give me the hook-up embodying the following apparatus: 2 variometers, 1 vario- coupler, 1 43-plate condenser variable, 1 23-plate variable, 1 detector and 1 amplifier. —George Leaderer, 336 Bryant Ave., Syra- cuse. See reply to Mr. Anorthy, and hook-up on this page. You will wire up only the one step, omitting the double-circuit jack in the circuit of the second tube. * * * 1. Can 3 Radiotron U-V 202 tubes be used in the place of the U-V 201 tubes in the Armstrong Superre generative published m Radio World, No. 19, dated August 5? 2. What plate voltage should I use on these tubes? 3. Will it be necessary to use different rheostats and transformers if these tubes are used? 4. What other changes will be necessary in this hook-up in order to use these tubes? I wish to use them on a transmitter later. — V. A. Gilbert, 332 Riverside Ave., Spokane. 1 and 2. While these tubes may be used in the circuit you mention, it is not advisable as they are not meant for that purpose. Higher plate-voltages will be required for operation. It is best to use either the 201 or the Western Electric V-T 2. These tubes may be used also in a small, low-power transmitter. 3. It will not be necessary to change any of the transformers, but we think it advisable to use a rheostat that will stand a slightly higher current without any danger of burning out 4. No other changes are necessary. * * • Can you give me the address of Dr. H. V. Hillman and Dr. Clarke F. Fletcher, published in Radio World, No. 42, dated January 13, in connection with their method of heating disease by radio?— F. A. Chap- man, Box 526, Wellsburg, West Virginia. We refer you to the photographers who furnished the illustration, Kadel and Her- bert, 153 East 42d street, New York City They will give you the information, with which we were not supplied. * • * Publish a regenerative hook-up using the following apparatus: Vario-coupler, 23- plate condenser, W-D 11 tube, batteries, and phones.— lack Brown, Wenatchee, Wash- ington. If you will consult Radio World No. 39, dated December 23, page 19, "With the DX Nite Owls," you will find a hook-up such as you want * * * / have a regenerative set, but, owing to the fact that I am located about three blocks from the central power house of the B. R. T„ I am bothered with a terriffic hum- ming in my receivers. I also have the tele- phone company almost a half a block away. How can I remedy this, as I can't do any work at all except on very local stations. — Joseph Adams, Ridgewood, New York. If you will refer to the answer given R. V. Andrews, Perryville, Ohio., under "Answers to Readers" in Radio World for January 20, you will find two ways of elimi- nating the hum. In the first a primary of a 1-inch induction coil should prove efficient. In the second, you will have to wind two coils of 40 turns each on a cardboard core, and arrange the sliders as shown, with preferably a fixed condenser shunting them. • * • Is the Flewelling circuit practical? Is it superior to the three-unit variometer vario- coupler regenerative set? — Morris Dorsey, 604 Woodward Ave., Atlanta, Georgia. This is a very practical circuit. It is not ethical for us to criticize one circuit in favor of another. Excellent results may be obtained with either, depending upon the way in which the apparatus is handled. Know your circuit and how to work it and you will get excellent results. This applies to a crystal circuit as well as to an Arm- strong Superregenerative. * • » Give me the hook-up necessary for the panel published by Cranby Meyers in Radio World, No. 42, dated January 13.—/. L. Anorthy, Waynesburg, Pennsylvania. Hook-up you desire is published herewith. The parts necessary are 2 variometers, 1 vario-coupler, 3 tubes, 3 rheostats, 3 jacks, 3 sockets, 1 grid lead and condenser, 2 for careful tuning-in. As you seem, by your letter, to be getting quite a distance we fail to understand how the volume can be so low. Most of the regenerative tuning is done with the condenser CI and the rotor of your coupler. Try using this set on a loop, as that is what it was originally designed for. Remarkable results have been accomplished with this circuit on a loop when properly tuned. * * * How can I increase the strength of my received signals? I am using the De Forest D. T. 600 crystal set, and wish to cover greater distances.— M. Seibert, Clifton, New Jersey. You can increase the signal strength by putting one or two stages of audio-fre- quency amplification on. A suitable diagram appeared in Radio World for September 2 under "Answers to Readers," in response to an inquiry by H. S. Houston. * * * 1. Can a W-D 11 tube be used in the re- flex circuit described by C. White, on page 11 of Radio World, dated January 20? 2. How high should the B battery voltage be? 3. What kind of transformer is used? 4. What kind of potentiometer is used?— John H. Newton, 482 North Sixth Street, Newark, New Jersey. 1. No, the W-D 11 tube will not function properly in this circuit It is better to use the regular hard tube such as the U. V. 201. 2. The voltage on the B battery should be 60 volts variable. 3. The transformer is the regular audio- frequency transformer used in regular audio- frequency amplification. One of fairly high ratio is preferable. Rcranaratlv* circuit published In amplifying transformers, panel 7 by 18, cabinet, 60-volt B battery with 22^-volt tap (1 22j4-volt battery and 1 45-volt will suffice ; hook them in series, and tap off for the 22j4-volt), a battery, dials, and bus-bar wires. * * * Can I use De Forest coils (D-L 50 and 75) in the DX receiver described in Radio World, No. 43, dated January 20, by Ortherus Gordon? How can I shield this panel effectively?— John F. Neary, 5745 Mosholu Ave., Riverdale, New York City. Yes, you may use these coils. The best way of shielding your panel is to paste either heavy tinfoil or light-gauge copper- foil on the back of the panel with shellac, taking care to leave space surrounding your fastening screws sufficient to dear all the apparatus. / am using the Armstrong Superregenera- tor built according to the specifications in Radio World of September 16. / have a 160-foot outdoor antenna, and everything called for in the article, but I do not get sufficient volume in the received signals. What is my trouble?— Jack Mason, Read- ing, Pennsylvania. This circuit is rather critical, and calls The regular 200-400 ohm potentiometer can be used. We suggest the Bradliometer, which is a carbon unit potentiometer, and gives finer adjustment * * * I am building a crystal set, using: 1 vario- coupler, 1 condenser, crystal detector, and I should like to know which would be best to use: 1 43-plate condenser, or 2 23-plate con- densers.—V. R. Langdown, 18 Chestnut Street, Princeton, New Jersey. You do not mention where you wish to use the condensers. We advise you to use the 2 23-plate condensers, putting one across the secondary or rotor, and the other in the primary, with a series-parallel switch, so that it will be possible either to shunt it across the primary, thus increasing the wave .length of your set, or to put it in series, allowing you to cut down your wave length. • * * Can the W-D 11 be used in the Reflex Circuit, described by C. White in Radio World, dated January 20.— Charles Moloney, 36 Preston Street, Hartford. Connecticut. Not successfully. This tube is primarily a detector, and is not very useful in circuits such as this, although it can be used. We advise the U. V. 201. Digitized by Google

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20 RADIO WORLD With the DX Nite Owls A Six Months' Fan Sends His Free* O. B. Martin, CM Raftway g»*h— as BosM- tat, Kaaaaa dtj, II H I HAVE been a "radiophan" only six months, and don't claim to know very much about radio in general, or any part of it in particular; but I feel called upon to take issue with Mike Podhorn,. of Wood River, Illinois, after reading his rather sarcastic comments in Radio World No. 42, dated January 13, on the receiving record of Arthur Lindstrom, of Baraboo, Wisconsin, in Radio World No. 37, dated December 9, 1922. Mr. Podhorn states he has quite an expensive set, has been in the game three years and has never heard music from a western station. This does not, to say the least, speak very well of his ability to operate his set unless there is something radically wrong with its construction. I do not think there is anything so unusual about Mr. Lindstrom's record in hearing from coast to coast and border to border with a set having one step of amplification. I am giving my record, made January 15, which covers practically every point of the com- pass from Kansas City, the greatest distance being KHJ, Los Angeles, about 1,800 miles. I am using only one tube, no amplification of any kind. Most of the stations heard were while WDAF, the Kansas City "Star," were on the air, which makes me proud of my record, as the "Star" is considered a hard station to tune out when so close to it as I am. •KDKA, Pittsburgh; WGM, Atlanta; *KSD, St. Louis; *KFAF, Denver; WLAJ, Waco; *WWJ, Detroit; *WAAN, Cedar Rapids; *WAAK, Milwaukee; WAJN, Topeka; *WOC, Davenport; WBAP, Fort Worth; KHJ, Los Angeles; *WLW, Cin- cinnati ; WB AD, Minneapolis ; also the Fort Worth "Record," but I did not get their call letters. I am using a Reinartz tuner, which I constructed myself. The entire set with all accessories from antenna to ground did not cost over $35. If Mr. Podhorn wants a copy of it, he will find it on page 23 of the same issue in which his letter appeared. I have experimented with several different kinds of equipment and many different hook-ups, with varying success, and several complete failures, and from my experience I favor the Reinartz over all others. 'Indicates station heard through WDAF. * * » A List of 13 From WHH» E, Gilbert, Jr, Box 1277, Alliance, Nabraaha THIS is a list of the stations I heard on the night of January 16: WAAK, WHAN, WHB, WFAA, WLW, WCH, WBAP, WSD, KUO, KZN, KSD, KDGU, KHJ. ♦ * • Working at Odd Times From Eraaat A. Dibble, Rockaway, New Jeraoy T HAVE a Paragon special and Paragon * type DA 2-ampIifier, with an antenna about 140 feet long and 35 feet at the highest end. It is a single-wire, and it crosses the canal. I have another antenna, also a single-wire, about 75 feet long and 18 feet from the ground. This I often use as a counterpoise and also a ground on the city water pipe. During the past month I have worked my outfit only at odd times. I have received the following list of stations on a detector tube, and many of them I am able to work in .on the vocal loud- speaker, so that they may be heard plainly in different parts of the house. I have worked WOC in especially' well on the loud-speaker : 'HE Editor af RADIO WORLD [ to rooahre akatehee the "DX Nito OwW recorda with a view af Sand hook-ape el neatly In black ink, provided of the various Write on eaa aid* af the paper only. The letter* aad book-ope will be pob- behod la the earliest possible numbers si RADIO WORLD. RFC, KOP, KSD, KYW, WAAM, WAAS, WBAM, WBAN, WBAP, WBAY, WBS, WBT, WBZ, WCAE, WCM, WCN, WCX, WDAC, WDAF, WDAJ, WDAP, WDA2, WDAW, WEAF, WEAM, WEAS, WFAJ, WFAK, WGAM, WGAS, WGI, WGM, WGR, WGY, WHA, WHAB, WHAK, WHAM, WHAS, WHAZ, WHB, WHK, WIAC, WIAM, WIAO, WIAZ, WIP, WJAN, WJAX, WJZ, WKB, WKAC, WKAY, WLAD, WLAC, WLAG, WLAH, WLAK, WLAP, WLAW, WLB, WLK, WLW, WMAC, WMAF, WMAJ, WMAK, WMAM, WMA2, WMAS, WNAC, WNAN, WNO, WOC WOH, WOO, WOR, WOS, WPI, WRAU, WRL, WRW, WSB, WSL, WWJ, WWL, WWX. WWZ, NOF, WAA2, 2X1, 2XJ, 2XAI, 3XW, WLAL. * * • In 15 Minutes ' From C A. lynch, 4121 BaUevue Anew, Detroit, MlcUcaa I HAVE been reading Radio World with much enjoyment since last April. With Frank S. Meyers' hook-ups (No. 3), illus- trated in Radio World, No. 42, dated January 13, I picked up WFAA, Dallas; Kansas City Star, and*KDKA, Pittsburgh, all in about fifteen minutes. My set con- tains a home-made vario-coupler, one 43- plate condenser, one W-D 11 tube and the electric light socket for the antenna. * * • Does Not Use Amplifiers From L. D. Ick, Bon M, Lovffia, Iowa t-jERE are some of the stations I have heard with my home-made set, which cost less than $10. I do not use amplifiers : KYW, CJCB, WOI, KDKA, KSD, WGM, WHB, WYF, WDAP, WMAD, WHAJ, WAQ, WIAK KFAF, WEAF, WBAP, WFAA, CJCK WHAF, WLW, WNAZ, WWJ, WCX, WHAZ, KHJ, WGL, WLAG, WMAF. All come in well. At times I can remove the head set and hear the music. » » * A Record from Indianapolis From Cecil Partner, tU Lafayette Av AS a devoted radio fan and reader of Radio World I send you my record. My set consists of a detector and two-step audio, and two-step radio-frequency ampli- fiers. I have the latter for experimental use only. I have heard all stations on the detector and audio-frequency amplifiers. The farthest distances are: WMAT, Duluth; WBZ, Springfield, Massachusetts; PWX, Havana; WOAI, San Antonio; KLZ, Denver; KHJ, Los Angeles. The total is ten, which vary in distance from 30 to 2,000 miles. I have just erected two new antennas. One is a four-wire, 75 feet long and 30 feet high. The other is a one-wire, 125 feet long and about 25 feet high. The rwo tune practically the same, but I get a little better signal strength on the one-wire. I should like to hear from any one wish- ing to purchase a complete set. * * * A Three Nights' Record AekeriHa, North Carolina 1HAVE a one W-D 11 tube set with no amplification, with which I have heard the following stations in three nights dis- tinctly: WGY, Schenectady; WOR, Newark; WHAM, Rochester; WCX, Detroit; WAAK, Milwaukee; WIP, Phila- delphia; WOC, Davenport; WEAF, New York; WCM, Memphis; WWJ and WCX, Detroit; KDKA and WCAE, Pittsburgh; KSD, St Louis; PWX, Havana; WHB and WDAF, Kansas City; WWI, Dearborn; WDAP, WMAQ and KYW, Chicago; WBAP, Fort Worth; WGM, Atlanta; CFCA, Toronto; WJAX, Cleveland, and WLW, Cincinnati. I think Radio World is the best radio magazine on the market, and shall continue to buy it as long as you publish it • * • A New York City Record From Marcel SOs, New York City A7TER reading the records of many fans I have decided to send my list in: WDAF and WHB, Kansas City; WSB and WGM, Atlanta; WOH and WLK Indianapolis; WCAE and KDKA, Pitts- burgh; WDAP, WMAQ and KYW, Chi- cago; WIP, WOO, WFI and WPJ, Phila- delphia; WHK and WJAX, Cleveland; WWJ, Detroit; WWI, Dearborn; WBAP, Fort Worth; WHAS, Louisville; WMAB, Oklahoma City; WOC. Davenport; KSD, St. Louis; WLAL, Warren; WLW, Cin- cinnati; WDAJ, College Park; WGY, Schenectady; WGI, Medford Hillside; WBL, Springfield; WHAM, Rochester; WMAK Lockport; WNAC, Boston; WMAT, Duluth; WMAF, South Dart- mouth; WBT, Charlotte, and 15 nearby stations. Once I tuned in 17 stations. • • * Did Not Keep Tuning From E. L. Landau, Bethany, miasm ¥ READ the Radio World every week, * and have been keeping up with the DX night owls for some time. I listened to CFCA, "Daily Star," Toronto, some time ago from 5:30 until 6:15, when they signed off. There are about seven high-powered stations working at this time in my neigh- borhood, but these did not interfere with CFCA. I did not have to keep tuning to hold them. Among the stations I have heard in the last two weeks are: CJCG, WGY, WWJ, WAAP, WCAS, WCX. WDAF, WEAY, KFAD, CJCG, WHAS, WHB, WJZ, KHJ. » * * 2,200 Miles from Winston- Salem From Edward Fens, Bos S5S, Wine tea -Salem, North Carolina D ECEIVED KFAP, Butte, Montana, AVvith detector and 1 step. I find a 23-plate condenser across the aerial and ground helps tuning. I use a three-wire aerial; fifty feet high and fifty feet long. I have the longest record heard of in Winston-Salem — over 2,- 200 miles. Among the stations I have heard are: PWX Havana; KSD, St Louis; WHD, Kansas City; WFAA. the "News." Dallas; WGY, Schenectady; KDKA, WLK WHK, WDAE, WJAX WHAM, WCAE WEAO, and 49 others. (Continued on page 26) Digitized by Google

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RADIO WORLD 21 Spaghetti Tubing and How It's Made UP to about ten years ago the common practice of insulating short terminal and connecting wires was by the use of cotton sleeving, or braided tubing, then also known as stockinet; after the ap- paratus was finished, this sleeving was given a sufficient number of coats of varnish to produce a smooth surface. Where such connections were subjected to moisture or oil, as in motors^ dyna- mos and transformers, the dielectric strength of the varnish gradually weak- ened and finally broke down; and where high temperatures also prevailed the dis- integrating process was so rapid that the insulation afforded only temporary pro- tection. Some one, possibly preferring a shorter name to "M-R Impregnated Varnished Tubing," says the New York "Mail," and aided by the resemblances of the material itself, dubbed it "macaroni'' and the name stuck until the smaller sizes became pop- ular. Since then "spaghetti" has been the designating shop term. During the war the United States gov- ernment tested several makes of "spa- ghetti" and many thousands of feet were used in radio and other work by the vari- ous bureaus of our own government, as well as those of foreign countries. When manufacturers of electrical ap- paratus took up the production of radio sets they naturally used "spaghetti" on leads of exposed wiring, primarily as a protection against "shorts," although the "dressed up" appearance thus attained was at once recognized as an aid to selling. The three styles of "spaghetti" now on the market may be briefly de- scribed as follows: Base of cotton sleeving impregnated through and through with varnish and baked, then given from eight to ten ad- ditional coats, each coat being baked and rubbed down. This is the genuine "macaroni" in the larger diameters and "spaghetti" in the smaller sizes. The wall around the -sleeving is thus built up of nearly a dozen layers of varnish, is_ homo- geneous and of tremendously high in- sulating value. As the final coat is rubbed down the finish is smooth but not bril- liant. Dielectric value approximately 7,000 volts. Characteristics already de- scribed. Here the cotton tubing is treated with a dressing or filler, instead of varnish, dried and then dipped five or six times in varnish, each coat being baked dry before the succeeding one is applied. This method produces a tube with a high gloss that is moisture proof, oil resisting and, when properly made, will withstand breakdown tests up to an average of 5,000 volts. And it is difficult to determine quality by either price or appearance, as some of the most highly polished are built up entirely of collodion, cellulose, or other guncotton compound, to which castor oil is added to retard hardening, and as they contain absolutely no varnish whatever they soon become hard, brittle and crack; then, too, they are highly inflammable. White or colored cambric cloth is cut in narrow bias strips, rolled lengthwise to form a tube 36 inches long, and cov- ered with an insulating compound resem- bling (but containing no) rubber. To produce yellow tubing, amber colored compound is used over white cloth, whereas both cloth and compound are of the same color when other shades are made. In every case the coating is transparent, flexible and will give excellent electrical The Dead End Effect Explained END lots in radio inductance coils is of great importance to all amateurs who construct their own sets, says the New York "Globe." It is also a thing that should be guarded against when purchasing a set already completed. This loss is one which may be so great as completely to prevent reception of signals on a certain wave length. The effect is seldom considered in home-made sets, and at times even manufacturers do not guard against its troublesome effects. All inductance coils possess more or less distributed capacity, depending upon the di- mension of the coil, its insulating properties, and the nature of the supporting form. Ca- pacity is far greater in a coil having more than one layer of wire than in a coil which has but a single layer. If only a portion of the wire on the coil is used the remainder will have a certain fundamental frequency or wave length due to the inductance of the unusued portion and the capacity of the coil as a whole. If the value of the unusued part of the coil has a wave length approximately equal to the wave length at which reception is desired, a great portion of the receiving currents will be absorbed by the unused cir- cuit As an experiment connect a small, vari- able condenser across the terminals of the coil. Vary the condenser and note that at a certain point, if the values of the coil and condensers are the proper ones, the signals will disappear. Now, if the cou- pling between the test coil and the receiver is very weak these effects will not be no- ticed. If it is very close — which is a condi- tion when only a part of the winding of a coil is in use — the effects will be more apparent Japan Speaks to New York THE New York "Times" radio station has copied a twenty-two-word mes- sage direct from station JAA, near To- kio, thought to be the first time a com- plete message from Japan has been re- corded in New York. It is difficult to tune in the Japanese station from the eastern coast of the United States, be- cause of interference created by the powerful French station, UFT, on the outskirts of Paris, operating on practi- cally the same wave length, 14,600 meters. One morning last week, at 2:07 o'clock, the French transmitter was standing by, as were stations on the Atlantic coast of this country, giving the Japanese dots and dashes opportunity to register in New York with great clearness. Ordinarily it requires several hours to get a message from Tokio to New York, for it must be sent to Honolulu, then re- layed to San Francisco, where it is put on the land telegraph lines and sent across the continent It takes at least three weeks for a letter to travel from Japan to New York. Radio spans the 9,000 miles across the Pacific and the United States in a fraction of a second. protection up to 1,000 volts in ordinary apparatus where it does not come in con- tact with water or oils. This form of "spaghetti" is ideal for radio instruments inasmuch as it offers insulating protection with a factor of safety many times in excess of that re- quired: its low cost permits of its liberal use and where more than one color is employed to trace out different circuits the result is an improvement in appear- ance of the home made set. CJV6 Wireless Receiving set is complete 0 witJjoujL r WHEN your boy points to the Mag- navox trade mark and says "Dad, that's the real reproducer," he sums up pretty much the whole story "of Magnavox supremacy and radio enjoyment. To enjoy all that radio offers in the way of daily concert.Iectureandncws, ask your dealer for a re- ceiving set equipocd with Magnavox Radio, the Reproducer Supreme R- ' Magnavox Radio with 18-inch horn: this instru- ment is intended for those who wish the utmost in amplifying power; for large audiences, dance hall*, etc R-3 Magnavox Radio with 14- inch Horn : the ideal instru- ment for use in homes, of- fices, amateur Stations, etc Model C Magnavox Power Amplifier insures getting the largest possible power input for your Maenavox Radio. 2 Stage 3f When you purchase a Mag- navox product you poascs* an instrument of the highest quality and service. MtignutoY products can be had of good dealers etTTV uhere- VC'nte us for copy of m-u illustrated booklet The Magnavox Co. Jr N. V. OftVc: 370 Seventh Aw. J/fAGNAVOX Ohe Reproducer Supreme Digitized by Google

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2 RADIO WORI,D ARE YOU INTERESTED FOOTLIGHT NEWS AND GOSSIP? If you want to keep posted on everything connected with the American stage read NEW YORK STAR $4.00 a year (52 U.ue.) $2.00 Six months $1.50 Three months 10 cents a copy Trial Sub. Offer NEW YORK STAR 1493 Broadway, N. Y. C. Send New York Star to my address trial sub. for three months (thirteen issues) for the accompanying $1.00. Name Street No. City and State. Don't- DROP your bulbs more than once a day. You may dent the glass or, possibly, shake some of the ions off the filament. Run your aerial across more high- tension lines than you have to. It may not kill you, but you'll never look the same in a wooden overcoat as you do in a Morris chair. Burn your bulbs up too high. It looks pretty but it puts an awful drain on the battery. Listen to a beginner's advice — go to someone who knows more about it than yourself. Try to receive without tuning. Coue never could make a car run by auto- suggestion, and you can't tune in De- troit by just thinking about it. Try to drive talks into your panel. Machine screws look neater, and there isn't so much chance of denting the panel with the hammer. Expect the battery to last forever. A man's life is limited to years, a bat- tery's to months. The life of each de- pends on care. Make your tubes "blue." You know how it feels to be blue but you don't understand how you make the tube feel. It doesn't work well after a few blue spells. Cut down your B cur- rent. When By Allen Donne YOU can tune in on any station you want, without being interfered with- — You can fix your own tubes, as easily as you fix the inner tube on a car You can walk into a radio store and come out with just what you went in for, and nothing more You can get someone to explain the ac- tion of your favorite circuit in a way that you can understand • Someone who has been in radio a month more than you have doesn't try to show you up as a numbskull The CQ hound on the next block under- stands that you don't have to hear him sign 66 times in order to understand him YELL "EUREKA" 'cause you've found PARADISE! Quick Work by a Radio Druggist A PHYSICIAN in Bayonne, New Jer- sey, attending a patient suffering from influenza a few days ago, ordered a pre- scription by radiophone. The druggist, A. C. Nuber, Jr., happened to be at his set, and the prescription was filled and delivered in ten minutes. A Radio Type Machine ANEW type-setting machine with an at- tachment for receiving wireless copy directly is claimed by a French inventor. According to his statement, the machine is so simple that it can be handled be a child. Quality Radio Products Dictograph Headsets and Loudspeaker! Cutting A Washington Radio Sets Universal 3 Plate Vernier. 23 and 43 Plata Condensers. Radio Storage Batteries Jobbers and Dealers: Write ar Wire For the Biggest Proposition in Radio. Frederick H. Pruden Incorporated Lerner Building 993 Bergen Avenue Jersey City. N. J. a Let Radio Radiate Your Home List Our Price *8 .00 Etsemann Phone* S3. 25 16.00 Western Electric Phones extra ear caps and muf- flers 7.50 25 00 Federal Jr. Crystal Seta.. 12.50 5.00 Fiaher Varlometera and Couplers 2.75 1.50 Kleenex Vernier Rheo- stats 93 5.50 Workrlte Bakellte 180 DeKree Coupler 3.50 1.00 Paranon Baiellte Socket. .50 1.75 Brlsht 8tar "B" Bat- teries 1.15 12.00 Dlctorsraph Phones 6.50 60 00 Cutting Washington Bs- generaUve Tube Set.... 27.50 Write lor tree catalogue Perfection Pays Parcel Post Pe rfectibn RadioCorp. of America 119 WEST 23RD STREET, NEW YORK 1 West 37 Stf#/M»«iMK)NewYorl^ The Volume of the Atlantic and the Smoothness of the Pacific A & P Loud Speaker makes a theatre of your home. Every note will sing out as if the Broad- caster were right in your Speaker. Why listen to stuff that sounds like a tired phonograph record when the A. & P. Phone LOUD SPEAKER gives faithful reproduction — with triple volume, clear and sweeter than very expensive speakers. $4.95 POSTTAGB PREPAID Dealers BACK write Note: The A. cY P. Phone Loud Speaker owes Its quality to the Special Alley used and to the peculiar Acoustic Properties ef Its design. WE CARRY A COMPLETE LINE OF STANDARD PARTS AT I RATES NEEDED BY ALL AMATEURS I RADIO-WIRE TABLES, BY FREDERICK J. RUM FORD, These tables, shewtns the number ef fast la • pesssd and fractions ef a pound, WORLD aa tea Iowa: No l — Enameled Mas-net Win. RADIO WOULD. No. M . deu wet* published us RADIO _ . _ - — - ~. .... ... dated Ne». IS. Max 1 fslesrla OstM-Oscered Wire. RADIO WORLD, Nfc 18, dated Nee. S3; Ns. S — Double Ootton-Oersred Wire. RADIO WORLD, He. »«, dated Dee. a. No. , — . No. 5 — Decbia aall-Ctwered Wire, RADIO 18 sects a cm. at the compute set ef 8 Order new. Beery amateur bonder should bat* la KlDea.1*. paaTjaad at tables constantly at band. Toe supply at RADIO WORLD, 1495 BROADWAY, NEW YORK. 1 llDlle Hle-C**ered Wire. RADIO WORLD. No. IS, Dated . WORLD. No. 4*. dated Dec. 10. Bant to any si the complete set ef 8 copies far f 6 cents. Or start your subscription Digitized by Google

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RADIO WORLD 21 How Broadcasting Is Done FOR those who have given little thought to what takes place at a broadcasting station while they are being entertained and instructed, C. W. Horn, superintendent of Radio Operations of the Westinghouse Electric Company, recently addressed a radio audience from Station KDKA on the sub- ject of broadcasting stations and the con- ditions confronting those who have their operation in charge. Mr. Horn said in part : "A broadcasting station consists of cer- tain apparatus so constructed and arranged that it will pick up sound waves, transfer them into electrical energy, amplify them, and then by means of radio transmitters radiate them through the ether. "The first thing to consider is the trans- mitter itself, which makes possible the radia- tion of energy. This transmitter makes use of the well known vacuum tubes which are operated at very high pressure in the Westinghouse Stations at about 2,000 volts. A set of these tubes,' known as oscillators, are so connected and arranged in a special circuit that they generate what is called high frequency electricity. The electricity which lights your home travels in waves at the rate of about sixty per second, whereas in this high frequency electricity there may be a million or more waves each second. This high frequency current is transferred to the antenna and radiated through space, acting as the carrier wave for the music or speech which you pick up on your radio receivers. To these oscillators are coupled a number of tubes called modulators, whose function it is to control the radiated energy in such a manner as to reproduce faithfully and with- out distortion the spoken word or music it is desired to transmit. "Now let us look at the microphone in the studio. This is an instrument which is designed to pick up sound waves and con- vert this mechanical energy into electrical energy. Most of you are familiar with this instrument either from actual experi- ence or from having seen photographs of them, but you may be surprised to learn that they are practically the same as the transmitter on your ordinary telephones, with the exception of certain refinements found necessary for radio work. After this energy has been transformed into electrical current it is intensified by means of ampli- fiers until it has reached sufficient strength to properly control the large modulator tubes on the transmitting set previously de- scribed. When it is realized how many times this energy must be transformed from one form to another, it is remarkable that the quality and strength can be maintained without appreciable loss. "Each tone or note in music consists of a fundamental beat or frequency of vibra- tion, and a number of harmonics or partial vibrations. . - These harmonics contain dif- ferent percentages of the total energy in any note. The distribution of the energy among the harmonics governs the quality of the tone and also make it possible to dis- tinguish one instrument from another. It will, therefore, be seen that it is quite nec- essary to pick up all the harmonics possible in their true proportion, or the quality of the tone will be destroyed. To do this properly has required considerable study and experimenting. In die first place the studio or room in which the broadcasting is done must be thoroughly protected to prevent the reflection or reverberation of sound en- ergy. This is usually accomplished by lin- ing the walls, ceiling and floor with heavy drapery, and sometimes felt is used. In the new broadcasting studio of Station KDKA at East Pittsburgh, we have gone to con- siderable pains to secure this freedom from reflection. In this new studio, which was just recently opened, the walls, ceiling and floors have been covered with felt, over which with the exception of the floor, has been spread a sheet of muslin. Over this is hung in heavy folds a covering made of monk cloth. The floor has a covering of thick carpet over the felt. Special effort has been made also to exclude external noises and when one enters this room he is immediately conscious of the intense still- ness which prevails. "In this studio when a musical instrument is sounded the sound waves travel directly to the pick-up, or microphone and are not distorted as they would be if they were reflected from different objects or places about the room. "There is a kind of broadcasting which the average listener knows very little about, but which he nevertheless enjoys probably to a greater extent than the broadcasting per- formed in a studio, and that is when the material is picked up from a distant point, such as a theater, opera house, football game, etc To accomplish this successfully is rather difficult because it is not possible to rebuild the halls or theaters in which the performances take 'place, and for that rea- son we must accommodate ourselves as best we can to the conditions existing. One of the greatest drawbacks in this kind of broad- casting is that the microphone picks up echoes, especially in large halls and in churches. Opera is especially hard to pick up, inasmuch as the singing is varied, and takes place at different points on the stage. At Chicago our Station KYW has ten micro- phones scattered about the auditorium where the Chicago Civic Opera Company renders its selections. An expert sits in the audience with a small switchboard in his lap and cuts in the proper microphone for whatever type of performance is being offered at that in- stant. He uses a different microphone for a solo than he does when the orchestra is playing, and he must make the change in- stantly at the beginning of each selection. Needless to say this man knows all the operas by heart." Attention ! Fans and Amateurs ! Have you built your own receiver f Are yon experimenting- with any par- ticular hook-up f Are yon improving yonr let? Are yon doing any interesting construc- tive work in radief Why not shore this knowledge with your thotuandt of brother font who read RADIO WORLD every weekf We want picture* of receiving acta with description* of how yon overcame some WHculty, or of any additional part or salt that you have added to obtain better results. These are the things that, prob- ably, the other fellow is looking lor. Send in your Informations pictures or what- ever you have done to improve the art. Remember the beginner is looking for We intend to print In this . . . week, pictured Information, and descrip- tion of value to radio amateurs. If you have found a newer or better way of doing anything, don't keep the secret but tell it to your thousands of brother fans. Send in a photograph of your set with or without accompanying diagrams and measurement. State whether yon figure in the picture yourself, or not, and with- out any expense whatsoever to you we will make an engraving and publish it. Be sure to write your name and address plainly on photograph. Send in your picture at once, or If yon have not made a set or done anything else in making radio material, tell the boy next door all about this offer. Address Technical Editor RADIO WORLD. 1493 Broadway. New York City. N. Y. RADIO SUPPLIES ALWAYS AT SENSIBLE PRICES All Wsv* Coupler, 180-300 Meters, with Fna Haok-Os $4.00 XV, V.lt Tubes 4.00 0 Vslt Dstsctar Tab*. 2.00 0 V.lt Amslluer Tabw 2.21 « Isek Dials .25 WHITE'S UTonnerlj Stanley Radio Supply Co.) US BAST 2SBD ST., HEW YORK CITY Oath with Order. Allow Pottage. ^AC-SHIELDS" bring in DX The invention of this i non-magnetic shield cuts out electric-stat- ic effects between vacuum tubes, over- comes interstage coupling, which causes distortion and unnecessary noises which make it diffi- cult to tune in dis- tant stations — also guards tubes against breakage. Your tubes should have them. Attached in a minute Jf your dealer cannot supply you toe will thip immediately by mail pottpaid on re- Pstsat P.ndlni ceipt of $1.00. ORANGE RESEARCH LAB. 41 North Uth Street East Orange, N. J. AUTOMOBILE CHARTS By Vasts* W. Page, M. 8. A. E. Uaftersi Mat— 24 la. x M Is.— PrUs lie. East. Lnetioe el lislttes System TresMee Ms*, fasjr. la this chart all parts ef a tjplsal double Un; tlon system oslns batter? snd saegneto an shown, and snraeruons sre siren tm leedllJ finding lgtneton trouble, and ettannWng them when found. Includes latest Delm. Oooaeattout (14 i II.) Pries. II Lnettae ef .OcdlBi sad Udjrleattsi .TrsaMw. Thu I* a oMBbtnatlea chert ebewlas all oem- ponante ef the approved form ef water cool lot group as well ns modem opsin. 'JubrieeUnn arstem. It shows all peUitt where ..defcea exist that may result _n engine erorbnung.^ both In Prln. II met. Labrhjatlce ef the Motor Car C - Tm. chart pi Hints the plan rlew ef a typical >lz -«7 Under chassis of stsndsrd design and outlliioo all important bearing point, requiring lubrica- tion, sad Is s talaabio soldo to the cornet deeigs and outline, requiring liibries- noa. and Is s taluablo guide to the comet lubrication of say modern oar. A practical chart for all Interested In motor est saeurMnanee. (14 a It.) Pries. II easts Walls sash ef the cam tare, itarti ll am, tee act sm all malntaaaao. lastrurtlcea far Mis eatln sensual k. Locum ef Starting sad Lighting ftrotemFasvta. Ibo moat complete chart m denes*, showing all part, of too modern automobile starting, lighting and Ignition interna, giving lastruetlena far ars- tematET location of aB faults la wiring, iaasos, motor or generator, switches snd all ether unite. Inraluable to mctorlata, chauffeur, and re- pairmen. Bis. 14 x 18 Umbo*, Prist. II oasts Locatl.s ef Fare Enilas Trouble Made tan. An enlarged end ret toed chart ohowlag clear aoo- tlanal news depleting all noruena of the Ford sewer plant and auxUlarj groups. It outline, eloarur all pert, ef the engine, fuel supptr ayateme, lenities snap end oodlng system, that in spt le sin trouble, detailing all derangement, that an liable to mat. an engine Ion power, ctart hard, et work Irregularly. Ibis chert atmpuOce unties ef all angina faults, snd Include. Instructions fer locating Ford electric starter troubles. mas II i II Inches. Prim. II easts Lent las ef Metoreytlc Trouble. Mode laay. Prln. 31 cost. The 8li Charti Sent for ti 00 THE COLUMBIA PRINT 14H Broadway, New York City No Free List Radio World has no free list. Th only copies sent out by the publish ers are to fill the ever-increasin| orders of the American News Com pany, the large numbers of subscrip tion orders received at the office o publication, and one voucher copy t each advertiser and advertising agen represented in current issues. Digitized by Google"

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24 RADIO WORLD ELKAY RADIO PHONE From Factory to You 3000 ohmi adjustable head- band, 5 foot cord, every phone guaranteed to give entire satisfaction, er money refunded. Equal to any $8.00 phone on the market. $U* postpaid. C O. D. ar Mcascy Order. Hm Bbj Co., 207 Market St., Newark, N. J WmT SPECIAL Brandes Phones NEW AND ORIGINAL BOXES $5.40 Per Pair Parcel post prepaid. Enclose Money Order, Certified Check PEERLESS RADIO CO. 71 THIRD AVENUE NEW TORE PARIS TO NEW YORK ON THREE TUBES The amateurs of Europe heard American amateurs very loud and clear on this new hook-up. Three audio and two radio frequency am- plification on three tubes. Denver comes in roaring on a loop aerial. Send for this special blue-print today, with complete instructions, naming parts and items used for con- structing this set. Trie* for tpnial blum print*— f 1.00 Dept. "B- 1663 Jerome Ave, New York, N. Y. RADIO BROADCASTING MAP FOB toe tenant of those Interested In Badls and those who an besoming Interested. Bead McNally St Company bare prepared s pubil- oation esntalnlni a wealth of information of greatest value. It shows In the noat eoaaprehen- slre way. ths location of ths broadaaattag statloni. Kites their daaslneatlon, the eell letters, wars lengths, ownership, etc.. of each. Everyone who wishes to get the maximum pUeanre and enjojment from Badlo should have a Band McNallr Badlo Map of United States. It la com- plete, accurate and up-to-date. The Band McNeil? Badlo Map of United States Is texts Inches In also. The locations of broadcast- ing stations axe ehown by dlstlnctlTC symbouL The cell lettere of each atatlon are given, alas ths wars lengths of each. The Badlo Districts with numbers are shewn In red and the Badlo Belay Divisions are In blue. Time tones are Included. Alpha- betical lists or stations snd alphabetical lists of cell letters are In the margins. Convenient pocket form wtth cover. Price 35c Each TFT7 ten b- ,T?TA PRINT • W YORK CITY Did You Know That— THE first Transatlantic signals were "put over" by Marconi on the night of De- cember 11 in 1901, that the sending station was Pdldhu in Cornwall, while the receiving station was at St John's, Newfoundland? The first radio stunt of any importance in this country was staged by the New York "Herald," when the international boat races between the Shamrock and the Columbia in September and October of 1899 were re- ported by wireless for that newspaper? The first "scoop" of this kind, however, occurred in England a year earlier (1896), when the Dublin Daily Express of London had the events of the Kingstown Regatta reported by wireless for publication in its columns? The first Marconi station in the world was constructed at the Needles, Alum Bay, Isle of Wight in 1897? The first paid Marconigram — as a radio- gram was then called — was radiated from that station in June of 1908? The message was over the signature of Lord Kelvin, and was addressed to his friend, Sir George Stokes? The first amateur to sit back and really be satisfied with the results he is getting has not yet come forward for recognition? The first American battleships to be fitted with radio were the New York and the Massachusetts (1899) and at that time sig- nals were exchanged at distances up to 36 miles ? The first visit of the wireless wizard to America was on the occasion of the inter- national races in 1899 and that Marconi has been here eighty- four times since? The first ocean newspaper appeared on board the S.S. St. Paul in 1899 and was called the "Transatlantic Times"? The first time a wiseacre refused to pre- dict a limit to the progress of radio was just a short year ago? The first concert is not always the best ? O.G. Gossip by Radio CHARLES REED JONES, formerly managing editor of Photoplay Jour- nal and Filmplay, who has assumed direc- tion of the "Stage and Screen" periods of the WHN radiophone station at Ridge- wood, Long Island, promises to give his audience real gossip that could be ob- tained from no other source. Mr. Jones has recently returned to New York City from Hollywood, where he has spent some time. Mr. Jones intends to carry forward the Local QRM THE true psychology of one phase of radio was expressed the other day when one amateur said to another: "Horace, ya poor fish, why don't you show some origin- ality and try out a new circuit on that outfit of yours just like the other fellows?" MR. TOM TUTTLE says that there aren't many points of similarity be- tween a violin and a radio, but he knows this: that if he were put in a room with one hundred radio receiving sets bringing in a concert from a near-by station, he could pick out his own. He says his is the only one that would bring in the announcements and then go dead for the duration of the concerts. SOMETHING had happened to make the toothless centenarian happy. Old, worn and wife-ridden, he had few comforts, but ladio was numbered among them and he i jd it to the fullest advantage. One evening, when a woman lecturer was talking about household affairs, he asked her in his century-old babble please to keep quiet. She obeyed him not Then the worn old gentleman experienced the thrill of his long life. He stretched forth hit withered hand and pulled the plug. The voice stopped instantly. He experimented for awhile, and then realized that he had just done what be had tried unsuccessfully to do all the long years. A grin spread over his face. Now he spends all his time letting a woman lecturer get a good start and men shutting her up just like that. He says he expects to enjoy his second hundred years more than he did his first policy of his predecessor, R. C Reed, in introducing stars of the stage and screen to his radio audiences. Rex Ingram, di- rector and producer of "The Four Horse- men," is one of the leading lights of film- dom who will be heard from WHN shortly. . RADIO MAILING LISTS 12.40* Rsdls Dee lore, cmeriac u. ». sy Status. par M tlM I.SI4 Sadie Mfn. sever lot U.S. fey States, per list IISJ« 1.717 Rsdls Safely J sheers, esesrlas U. 4. fey states, ear list Ill-M 2*0 Rsdls Stutlsas. per list M.H 257 Mfn. who make sad assessors seel sects Ssdle Sets, ear list....... •i i.-.v H" SS.SM (Issue Amateurs aad Mesas en sf Rsdls Statisas, par M »7.5t Ask far arise lists far Ceases, Estlsad. sojssr Jlsb. TRADE CIRCULAR ADDRESSING CO. I«« W. ADAMS STREET CHICAGO, ILL Good Luck and Happiness will Isll Under which Zodiac Sign were you born? What 7\Vtll tfll MAI I Under which Zodiac Sign were you born? What _ \ are your opportunities In life, your future proe- Ri* IS FAA* Jar pec to. hspplness In marriage, friends, enemies, W* WL M2/i-s" success In all undertakings and many other vital ^ " «--ssw que.tlon. a, indicated by ASTROLOGY, the most ancient and Interesting science of history? Were you born under e lucky star? I win tell you free, the meei troloeicsl Interpretation of the Zedlse 81 in you were bom under. Simply send me the ersot date of your birth I east of this notice snd postage, enclose 1 snd address. Your astrological Interpret*! snd sent to you securely sealed and paatl Wri" ^Stf?TAW,°3% (Dept. ») Fifth Avenue, New A B C of ATiatioB By CAPT. V. W. PAOK. This bosk eesnrlhee the aasls principles of erfsUon. tela) bo* a bailees sr dtrlglbls la mads sad why It Rests In the air. Describee bow on airslane flics. It shews in de- tail ths different parts ef an airplane, what they are snd what they da. Psmerihee all types sf air- planes snd how they differ In assartroaUsa: as well as detailing the advantages and easadranuges sf different types sf aircraft. It IncMsce a esca- pists ilk IIssmii sf sflatlsB tanas snd clear draw- lags sf leading slnlansa. The resdsr will Sad simple Instructions for uiapsaklng. settles ap and rigging alrplaaas. A full asswlltsa ef slrpuuss aontrsl principles Is glrsa snd sasthias sf tylsg an dtosassad at length. This bosk snswars si i aircraft, tl . jsass, IS* i - T plates. Press, 11. ts THE COLUMBIA PRINT le*s ■isedasu, Maw Tarts Ctty Newsdealers Attention Yon •herald keen a food i apply ef back s sabers of RADIO WORLD sn bias all tbt time. It has heea the rrarriseee ef assay fas an that a nsjrchaeer of RADIO WORLD far ths tret time will almost immediately want the' back Bombers, some ef which are already east ef print and some of which are eaflcalt te pvt. TBS PUBLISHER WILL FURNISH SACK NUsOJHS TO DEALERS DIRECT OR THROUGH TP AMERICAN NEWS CO. AND ITS BRANCHES. Dealers ahoald hold their uasotd copies far s reasonable length of time. RADIO WORLD o) October 28 contained a foil page of contests of back numbers to that date. IS cents any seven numbers for SI. 00. 14*3 Broadway, Now York RADIO "wOffL^ Digitized by Google"

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RADIO WORLD 25 RADIO PANELS CM eaaetlj u alae m ebltmd .wt*ta 1* IMM. u inck tblak. IKe per mm Inch, J/l« — Ale P*r aojiare Imb. Made* U»T>l^iM> alaafc fibre. Tale MMrUl MAS) otnarth, to In in ■ at re . aoSraaSbU. Mar te wara nd takaa * sin Balak. apcetal afar, tittle,. M«: t» WILEY t»J) • PANEL CO. SPEAKER Cejaale*. »H» alt aad eeri ••art If* eaklaet LDONNELLMFG.CO. ■at 7t Ah Artor. Nlak. THEY ARE GOOD far AU eliminated, dealera " R.dlo Mia lb. metal dial ud •lip is tbt MICA I1ICAPB0NV8 MO No Vera all Write for drain. Dlaoeunta M RADIPHONO ADAPTER $2.00 Her* la an efficient mm- nomlral way to uee »"f Vlctrola. Edlaon. Bruniwlet. etc.. M a wonderful laud .peaker. to ba eetlafeetory or m If your dealer cannot aupplj you rend ue IS.M wa will mall on* by parcel post prepaid. Induetrial Salc-e Enejlne-ejrlna; Co. •71 Braad Street. Newer*. M. J. Phone. Market 9023 Toe Nlftiee* Short Wave ■ Only SS.PJ A PP on 1 lb. L. W. GOODMAN DREXEL HILL, PA. Nerrlitawa. Pa., errttee: Llerealai Taea neaeer . Nerrlltawa. ra.. vrrree: fc-iei la^eeartrr wltk ay GOODMAN. Heard a relee. are ao. 10 aallaa eat (real 8aa Fraaeleee." DIN VCR "-a la ud aaak the atria. England Hears WGY on Loop Aerial SINCE December 24 many letter* hare been received by WGY from English radio fans, who report successful reception of the General Electric Company station. Probably the most remarkable reception was that of Captain Round, of the British Marconi Company, who, on December 24, received WGY on a two-foot loop aerial, and Arthur Brooke, of Liverpool, who, on the same evening, picked up the Schenectady station on a forty- foot indoor aerial Among those who reported reception were' A. Shaw, Colne Lanes; R. T. Hatton Evans. Penarth, South Wales; W. G. Boothroyd. Southport; J. W. F. Carded, Cornwall; J Ash worth, Bolton, Lancashire; T. B. Trott. Plymouth, and Thomas E. Henshelwoort. Inverness, Scotland. The Englishman who picks up an Ameri- can radio station most be a real enthusiast because most folks across the Atlantic are in bed by the time the American stations are getting into the air. London is five hours later than New York, so a London fan who picks up WGY at the beginning of its program— 7:45 p. m.— is listening at 12:45 a. m., his time. MM Broadway New York, N. Y. 1923 Will Not Be Complete! Without a Year'* Subscription to RADIO WORLD (52 numbers) $6.00 AM SI a year Pit™ for poet a ere to Cauda aad fare-bra rountrlre. The Mountain Comes to , Mahomet THERE is one angle of radio broad- casting that should be supported by every thinking citizen of the country, says the New York "Globe." Whatever we may think of the usual jazz pro- grammes which are used as a means of entertainment, we are bound to approve the type of radio broadcasting which brings the Sunday church services into the homes of those who are too feeble to attend church in person. Every Sunday morning there are thou- sands of people who never go outside their own doors, but who, nevertheless, are in attendance at one of the big churches throughout the country. Per- haps the church is only next door or possibly many hundred miles away, yet the music from its organ and the voice of its pastor penetrate into the homes of people who are unable for some reason or other to attend the church services in person. It is a modern version of the old story of Mahomet and the mountain. If there are people who cannot go to church then the church must go to them. The value of church broadcasting was emphasized first when the Rev. Ernest Stires of St. Thomas' Episcopal Church in New York City preached his entire sermon by radio, so that many who could not get to church could have the word of God brought into the home. Encour- aged by this attempt, greater power was used thereafter to make it possible to cover the bulk of the shut-ins who are scattered throughout the United States. Reports then came that sets were being constructed for shut-ins, invalids, hospi- tal patients, and others who were denied the privilege of getting outdoors. Orphanages, homes for old people, and even jails were fitted out with radio re- ceiving sets. In the South it is rumored that a fund is under way to provide sets for 1.000 churches where it has been im- possible to get a preacher regularly. Many a small church has fallen off through lack of a regular pastor. Radio is not expected to chance all this, but it is hoped to make the country church a civic, educational and cultural centre RADIO PANELS a-»tt" vn PAGESON COMPANY •t taale. Ma. WE ARE MANUFACTURERS OF FINE RADIO FURNITURE — CABINETS, TABLES AND ROLL TOP DESKS. Hee-oSreod, hand-rubbed. It THE SOUTHERN TOY COMPANY Radio Dhrialaa Hickory, N. C De Forest HEADQUARTERS RADIO STORES CORPORATION Oittrlbuttri II* WtST 14TM STRf ST. N .V. WTV mit-aill Public Libraries Y. M. C. A's. K. of Cs. Y. M. H. A's. Army Posts Social Clubs Industrial Libraries And others in this subscription group ordering subscriptions for Radio World from all parts of the U. Canada and foreign countries ? THE REASON Because so many Of their members Are interested in Radio That they want to read RADIO WORLD every seven days. Ask the Association or Club To which you belong To subscribe for RADIO WORLD The Oreol /Uwlralert Sat tonal * RADIO WORLD Now York City That Armstrong Circa So moch interest hi« been duplexed in I epecial article. "TESTED INVENTION i MAJOR ARMSTRONG AMPLIFIES SET M0. TIMES," by Jobs Kent, that appeared ia RAI WORLD No. 1J. dated June 1*. I9.V. the publ.tl decided to vat said* a number cat copira tor th e»r>o were not able to get lhi» itiur erhen |i liihrd. Cornea will be eent. p..«ipaid. on rece of 15c . or eend ir. mur aub.rript ion. 16 rtl for i year (Si laeura). SJ no «i« nvnthe. or SI W th mootha. and •uhec-iptmn be aurted w the imtue conum."! the artule al.nit Mi Arnt.tron«-a Ampl.fier.-RAMO WORLD. I Broadway. COMPLETE YOUR FILES OF RADIO WORLD FOR 1 §22 of Radio World are becomin. —rear Ml tha tt-aa. Waaan — hayaia. yoa * fraaa Nov. 1 to date at fifteen coata a copy. RADIO WORLD. MM Biaadaay. Now Tor* Ctty Digitized by Google

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26 RADIO WORLD (Continued from page 20) With a Home-Made Set From Joe McCormack, IMS Peach tree Street, Gadsden, Ala. I HAVE received the following stations in less than three months on a single- detector, no amplification, using a honey- comb coil, with tickler feed-back, two .001-variable condensers, (one in primary and the other in secondary) and change- over switch in series. This set is home made. Anyone having a set of this type, ? lease write. I will be pleased to give urther information. Here are some of the stations received: WJZ, WWJ, WLW, WMH, WOH, WSB, WAAX, WAAG, WCX, WEAT, WDM, WOK, WKN, WDAF, WWI, WHB, WWZ, Build Your Own Set "1MB RADIO CONVntUCTOV _ A book ohowiof Ivel vo priso hook- I ~% «m and Ml dotal* of hot how ■>ltJ baild |*B own act anter kaH to. I lEWMM < 00.. 74 DH IT. ram MWYOK King Sr. Variometer ISO to 800 meter*. Mo outside con- necting hardware parity loeeee. Blse 4«4"x4*4"xJ" Guaranteed by manufacturer direct to user. Retail price $tM Ask dealer to show same to 700. Aremco Mfg. Co., 30 East 23rd St., N.Y.C. An "Ad" Plan That Hit Radio Distributing and Anto Supply Co. TEL. COLUMBUS SSS4 •4 Weet (fth Street RADIO WORLD, 14*3 Broadway New York City. New York, December 2tth, 1S22. Gentlemen: — In starting our business ae a re- tail distributor of radio good*, the writer bad placed some advertisements in RADIO WORLD, while connected with another company, and Was so impressed with your pulling- power as an adver- tising medium that the suggestion was made that we advertise only in RADIO WORLD. Our plan has been, as you know, to take a column one week, giving an itemized list of our offerings with prices, and on the fololwing week to take but three- or four-inch space, mentioning but one or poesMy two special items, Although our store has not a particularly good tTt?0n'_J2r J!dvtrtUin« naa not only proved highly porfitable but has resulted In sufficient mail order business alone to give us a handsome profit from our advertising in RADIO WORLD. Therefore, we take pleasure in telling- you that we have found RADIO WORLD to be . most profitable advertising medium. Very truly yours, RADIO DISTRIBUTING dc AUTO SUPPLY CO B. K. OWEN. ' WGAQ, WBU, WIAB, WAAP, WEAY, WGM, WHAS, WHAA, WSY, WGY, WHAL, WHAO, WDAJ, WEAK, WOC, WAAC, WEAU, WGAN, WDAE, WOS, WIAG, WOR, WAAW, WAAB, WOI, WFO, WLAB, WCK, WRR, WBAO, WEAF, WBAP, WOO, WMAD, WLK, WOAI, WGF, WFAA, WDAP. WLAG, WMAK, WIP, WCAH, WBL, WGR, WMC, WEAS, PWX, WHK, WBAZ, WHAM, WDAL, WJAK, WAIO, WBAK WJD, WAAH, WCAU, WJAX, KYW, KDNA, KSD, KFAF, KHJ, KOF, WQAA, WNAV, WOAF WFI, WJAJ, WDAV, CFCA, WJAH, WMAF, NOP, WBAV, WTAN, WHAZ, WFAT, WPA, WKAL, WHAH, WNAC, WOAV, 2XD, 9ARU, 4FC, 2XD, 9AJ, SXA, 2X1. 9DYN, 1XB, 9KP. All of these are radiophone stations. The hook-up is on a separate page. * * * Results from Bulb Set Nearby From L. S. Muster, Anderson, Indiana. TjUST read in Mr. Kea ting's letter in Radio World, dated January 20, about the remarkable results he is getting on his crystal set. It seems that he is very much concerned about being told that his results are due to bulb sets near where he has his set I have experimented with the crystal set for the past year and have made one that gives the same results. I have tested this in the country four miles from a bulb set and find that I get better results there than I do in town. My set is 3 inches wide, 7 inches and 2 inches deep. I use a double coil primary and secondary, a 10-point wave length con- trol switch, a crystal detector, a phone con- denser and four binding posts, all mounted on a hard rubber panel. I do not use any amplification. I can use two and three sets of phones on this outfit. I get the following stations regularly and very clearly: WGY, Schenectady; KDKA, Pittsburgh; WWJ and WCX, Detroit; KYW and WAAF, Chicago; WSB and GYM, Atlanta; WHIB and WDKF, Kansas City; WOC, Davenport; WSY, Birmingham; WOH and WLK, Indianapolis. Other stations I have heard are WKAF, Wichita Falls; WFAA, Dallas; KSD, St. Louis; WKY, Oklahoma; WLAG, Minne- apolis; WLW, Cincinnati; WCR, Buffalo; WWZ, New York ; WOR, Newark ; WBAP, Fort Worth; WBAX, WilkesBarre, Pa.; WWX, Washington. My aerial is 2 wires, SO feet long, 25 feet high. To get results one must have a good coil, good aerial, the best crystal and good phones. I know that a crystal set does not have to depend on a nearby bulb set for results. All connection in the aerial and set should be soldered. » * * 135 Stations Heard From Edward Coffman, Qulncy, Ohio t-JERE is a list of DX stations received *■ *■ by me in the last 2 or 3 months which I think will compare favorably with that of B. L. McBride of Winchester, Tennessee, whose record was given in Radio World of January 6. I use a single detector bulb with a tuning coil (single winding, not sec- WALCON No Radio Frequency Transformers dWorMon. <U8taDt ■tBt,ons on ■ loop-perfect reproduction. THE BEST YOU CAN BUY ™#2*?z?zs£ rw"D'n*er„tbi8nd ,ruttrant'ed- rarta— " wiXuTc^-lBa. 'StfSLJJZZ. reflcx c,rcult ,anUh<* Price, $4.00. We pay postage. DealZl^nd1. iobbtre; Write 'or ™r attractive sales proposition, backed by national advertising. Manufactured by THE RADIO CENTRE, 2 W. Broadway, N.Y., N.Y. ondary) 3,000-ohm Manhattan headset and a single wire aerial, 92 feet long and 25 feet high. KHJ, KWH, KFI, Los Angeles; KUO, San Francisco; WNAC, Boston; WEAF, NYC, WJZ and WOR, Newark; CJCG, Winnipeg; CFCA, Toronto; WHAB, Gal- veston; WKAL Orange; PWX, Havana; WKAQ, San Juan. The total number of stations heard to date is 135. Ocean Forecast Messages The following arrangements have been made for issuing warnings of cyclonic dis- turbances off the coast of Queensland from December to April: By arrangement with the Commonwealth Meteorological Bureau warning of a cyclonic disturbance is dis- patched by urgent telegram (Sundays in- cluded) to the radio stations and post offices of the ports in the area likely to be affected. Radio stations will broadcast such warnings to all vessels, and, in special cases, the meteorologist will indicate when his next report will issue. At 4:30 p. m. (local time) daily, except Sundays, radio stations will broadcast an "Ocean Forecast Message," giving the state of the weather, direction and force of the wind, and state of the sea at 3 p. m. along the Queensland coast, followed by a fore- cast of probable conditions during the ensuing 24 hours. On Saturdays the fore- cast of probable conditions will be for the ensuing 48 hours. Heard at the Radio Counter A Conversation Between Customer and Radio Clerk Part XIII t(\\7EUL, sir, what can I do for you?" » » "I have just recently become inter- ested in radio, and I am thinking of pur- chasing a radio set. Could you advise me as to just what to do?" "As you say that you have never operated, I advise that you get an inexpensive crystal set to begin with. If you were to buy a more expensive one to begin with you might have a lot of annoyance by not knowing how to operate it. Not getting the proper re- sults, you would become disgusted with it before you had learnt its advantages." "That is what I was told, but I have also been told that small sets of this type are inefficient, and therefore troublesome." _ "Well, as the advantage of crystal sets lie in their simplicity of manipulation, you can learn more by operating one to begin with, and then after you know something about apparatus, by reference to different text books and magazines, you will natu- rally want to increase your receiving range, and will buy a tube receiver." "That is very explicit. Have you any of the crystal sets you mention?" "Surely, here are five different models, and while the principle on all of them is the same, they differ in workmanship, and the more expensive has of course the best apparatus. I would advise you to buy only the best, because it always gives the best results." "Is this all that I will need?" "No, you will need an aerial. We have some antenna sets already made up in boxes. You will attach the wires and insulators. Then you will need a pair of phones, and the same principle applies to these instru- ments as to the set. The best will natu- rally give the best results. You will find all the phone sets in the glass cabinet right below." "Well, if you think that is all I need, I will leave the selection to you, since I don't know one from the other. Will you wrap them up and deliver them to my ad- dress? Here is my card." "Certainly. Just one minute and I will have your ^^you^

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RADIO WORLD 27 HEADQUARTERS lo stores Corporailoa no v». M 8* pfV.to'l&,tTJriiMn loiift-tiia it's f/ie contact tnat count* The •pedal »*eeehor bronze clip! el the Na-eld W. P. 11 Secket i perfect contact renrdlew of any Tartarian la tabe prongs and bases. Moulded from can nine Con dan site, theae aocketa are made for aea with the famoua W. D. 11 tehee, operated by a eingls cell battery. The Na-ald Da Ua» V. T. Socket la of hhrhaat quality throughout. Its laminated phosphor bronxe atria ■ preaa irmly with a aide wipe action on the contact ptna, keep- ing aurface deaa aad bl- aming perfect contact. 77iesc soc feet's retail at 75c maeh Send stamp far dial, small- space socket, con- denser and R. F. Trans- former circulars. ALDEN-NAPIER CO. Dept, L n Wlttaw St. Saa1agflala\ Mass. GERMAN SET With Seiht Condenser, WD 11 Socket, A 4k B Batteries aad Phones. Special $15.80 This set can be made into Wave Meter for Calabratin*. Transmittina; or Receiring Set. Diagrams given with set. AEROPHONE SET Complete Crystal ReceiTing Set, with Phones. Coil mounted on base. Special. .$1235 CerdweU All Wawe Coupler. . 7M WD 11 Sockets 35 WD 11 Adapters Je- ll T Sockets, Moulded .15 Pathe Dials, f J5 Pathe Dials, 3" •» Pathe Dials, 4" M Variable Condensers, 43- Plate 135 Baldwin Variocouplera 3.75 Baldwin Variometers 330 Emco Variometers 630 Emco ISO-Deg. Variocouplera 530 Columbia Moulded Variome- ters 3.75 Back Mounting Inductance Switches .75 Mu Rad Radio Frequency Transformers 330 Jefferson Radio Frequency Transformers 430 American Radio Stores tSS Fulton Street (mail orders) 1987 Broadway New York City "Setting You Right" IN Radio World, dated January 13, page 23, we published a hook-up of the Reinartz circuit, in answer to an inquiry by C. W. Stewart An error was made in connecting up the first rheostat. ld In sealed packages only, the ever-Increasing Rusonlte fans. Priee. postpaid, mounted f fl. Sensitiveness Guaranteed JUL RUSONITE CATWHISKER 14-Karat Geld Multiple contact. O C Supersensitive C.0C Order from your dealer or direct from us. its Products Corp.. 2 1 Park Row. N. YOU DX HAMS! the book-tip srltb Have yon L layout In full also and all c BADIO WOULD No. 41. dated Jan. Ml This book-up actually roes sot sad arses the dlstsnss In, sad lays It at your tabus. It's a wonder! Can't be bast! atrsa If too never bars made a sat yourself, you ssa da it now. All that Is nocassary Is to lay the tan-rasas duurrsm of the paaal on yoor own panel sad drill sad sura yoor holes. Blnxpls. Isn't itt If you haven't this copy send IB ssnts ts Bases World. 1493 Broadway. New Tare. N. T.. sod sops will be Balled you. Or start your wis— hwlaw with that number. No Free list Tsj asany aaudsKU Isvcrarirers! KADI WORLD hae mo fro* Hat. On •amy aeat aa a Toucher to ssa eh adsailleoi i adTertieing ageat rayrMwrtad ia evurrea iaasvee. All other esypiae are paid for « or through the These FRESHMAN PRODUCTS Especially adaptable for use) In the FLEWELLING s— Circuit with . Tested VARIABLE GRID LEAK mfd. M1CON **** ica Condenser J|) 1 aUU Without Condenser T5c CHAS. FRESHMAN COMPANY, 97 Beekman Street, New York Tha Horn* of MICON and Anttnella ■ -MICON" ■£ _^^^_^SSJ TESTED HKA CONOXaSES M* s? I *»T""S H.Di.a i^aaaBB^a cmas. ruiRiw. oo. tBS*^^^^^ SBB «cw »o«. city a i r MICON Tested Mice. CONDENSER .00$ $1.00 At your dealers — other- wise send puaahaee price and you will be sup- plied without further , > charge.

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28 RADIO WORLD SEND MX TOUR PHONES for rapalrs. All mikn. Satisfaction tuarantssd. RtuonabU chargs*. gg. lfl Vfeet **m* t, Hem Tsrfc Cfty "* T** eat* lUMit *"* STANLEY RADIO SUPPLY CO. Ksw Task SPECIAL OFFER P.* A M atafc, a. J. Y. ORMOKT a. #. RADIO TOOL SIT TVs Sccvw Drirsn KM ia CEB CO, IN Park Plan, N«w York Cky A Set That's a Little Dif- ferent EDITOR, Radio World: Frank S. Myers, in Radio World, No. 42, dated January 13, requests that the fans tell some- thing about the parts of their sets. Also C White, consulting engineer, has an article entitled "To the Radio Amateur with Little Money to Spend." This is an answer to both. My set is a three-circuit regenerative, single tube, vario-coupler and two variometers. These coils are wound on tubes made of blue plasterboard and glue. The wire is of three different sizes, as I used scraps of what I had on hand. The leads from the rotors come out through copper tubes. This tubing is from the cooling system of an automobile. The knobs are spools from a 'Tinker Toy" set The dials are "Little Wonder" records. The switch blades are made from the case of an old alarm clock. The points on both inductance switches are brass-head tacks, and on the other switches are copper rivets. I have two variable condensers. One is made from a patent-medicine sign. It has two sets of leaves that intersect with a slid- ing motion, operated through the panel by a rod from the ever useful "Tinker Toy. The other is of the same type, but is made from old negative plates covered with tin- foil. Ihere is no body capacity to these. BARGAINS EVERY DAY 11 TEAKS ON TOT SAME SPOT LOOK AY OUE PUCES: PIMM PlsM 2-811*) Twlat Calls. , ...fl3.lt .... 4.7S .3* WMun n«.~ wimmr..T::::: tm DtFarast RUn Hmm Slntk Tuh Sett II. to 2.25 S.SS »-**[» ■'«•» films t> :::::: ; ; ; ; : : *J«h«ff-_vv.. SS.SS W. D. II MbH, .43 Batollts V. T. ntMts. ...... . .If r aatvad by Ota THE POST 'SOLDERING IRON Platinum Heating Unit— Interchangeable Tips — Universal Current (Large and BmaU) $6.00 Yoar Dealer or Write Awarded CarUSeata af ttitilliiiB. N. Y, Evening Mail Radio lastttat* POST ELECTRIC COMPAMY, g*r. S») ME. O.I St, New York FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City. Please send me RADIO WORLD for months, for which please And enclosed $ SUBSCRIPTION RATES: Steel* Copy * .15 Three Months 1.50 Sis If oaths 3.00 Oaa Year (52 Is—- 6.00 Add StOO > V BWign Postage. 51V «t- Both have a vernier made of sheet iron and tinfoiL The by-pass condenser is of mica and foil between two pieces of hard rubber- part of a broken photograph tray. The grid condenser is of waxed paper and fetal from a Ford coil. The variable grid leak is of hard rubber from the photograph tray. It consists of a switch lever with bole drilled in end, with short piece of pencil lead in- serted. This lever makes its own pencil mark. The rubber base should be sand- papered so it will hold the lead. The leak is connected to a three-point switch, which connects it with the coupler in the usual place, or with the filament or plate. Another switch— four-point— varies the voltage from the B battery. The detector tube ia only five inches behind the coupler, and the B battery is on a shelf on the panel, so all these connections are short Still another switch connects the negative side of the B battery to either the negative or positive side of the A battery. By connecting the leak to the and the B battery minus to plus oa A battery, reducing the B voltage, and tarmac filament very hot, distant stations are brought in with great increase in volume. I got hold of a 12-volt storage battery that had been thrown away, from which I got sufficient plates to make three fairly good cells. It has had no attention, except a little rainwater, in nearly two years. It it charged from a 220-volt D-C line, through 190 ohms resistance. I often use the set while the battery is charging. My vernier rheostat is wood— one af those little hoops, 5 inches in diameter which women use for fancy work. A single German silver or other re- sistance wire is wound on the outer circum- ference. The total resistance is about H ohms. It gives a fine adjustment. The panel is part of die footboard from an old bedstead. It is very large, as T need room to try out different circuits. It is covered with foil on inside and grounded My aerial is one wire, 130 feet long and about 38 feet high. I frequently use a small loop in plate circuit. With this set I get about all that is worth hearing east of the Rockies— from the call of the North to PWX; from Denver to Boston. I have never heard from the Pacific Coast, but I never listen in after , 11 p. m., Central Time. I once heard some phonograph records from Boise, Idaho. If I get a station at all I get it with good volume. I have never tried to see how many stations I could get in one night, nor have I kept count of total number received; but it is not less than eighty. I am claiming no records. I give all credit to our splendid broadcasting stations. I wish I could find words to express my appreciation of them. This may be of help to some beginner with limited means, and who lives where it is hard to get supplies.— F. Onderdonk, Calera, Alabama. Another Voice for Mr. Lindstrom p DITOR, Radio World: I have been in V t.J?<!!0«ame since Coherer days, or about 1908-1909. As a rule I don't mix in these novice discussions, but happened to notice, in Radio World, No. 42, dated January 13, the challenge given Arthur Lindstrom, of Baraboo, Wisconsin, by Mike Podhorn, of Wood River, Illinois. I don't (Continued on next page) |<f ^Bookon QswrfsUj r1**!--. J*» <Ml part JrSmhSk btoJL Digitized by Google

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RADIO WORLD 29 It.M IS.St . 7.M AM ax 8i IMC , 4.m riMM 4t n* CMk with RADIO ENGINEERING 00. t W1 Ml* Wbm* Hm YaHi Caw FREE 8HBLTONB LOUD SPEAKER Orlstaal BakMa vm a At $1U« Cm* aottk order WALTER SCOTT Mid 5b£5E"^* " ' Ur or C. 0. Z>. , movo\ 'ERIES NOTE THE INSULATED BINDING POSTS AND 7IW.WIRE CONNPCTOR NOVO M'F'G CO. RADIO MYSTERY TRACKED BY WIRELESS WILLIAM LE QUEUX Author of "MjuUmoi— H. of CnU," Tfc* tariff." Tko 1 B*«ry — — , u , latest mystery atory by Mr. La Qmu who •• rightly hw kM colled, The Muter of tko Mystery Story* f TkU U fiction bat Mr. La Quo ia • aaaaaW of tko Iaatitmto of Rods* ragloaan oad tkarofora wall fitted to write tkla f Hm plot U ■tor, Falaaaar. Ho ia , by Soottead Yard »o old to tko _Mom of a hmmi of erlatoaU who haro taurood tko om of air aim fete lawloaa akasteala | Foleoaor ovoataolly aotooa tko a*y«tory daring wkiak tko lataat aagiaa to roaHo aWalop tfca rooUo of today aad tko radio of tho futurm. Tko book yon eanot afford to aaias. f Our special prico to raodora of Moffat, Yard and Company Publishers 31 Uoioa Sqtuuro Wort Now York City RADIO WORLD MANAGINO EDITOR TECHNICAL KDTTOK i ss. im IMPORT ANT NOTICE 'rftat tad aSaVaa i ■ (CoahWrf /roa» prtctdmt see why Mr. Lindstrom's record should be questioned. I live about 35 miles from Baraboo. And even listeners with singlc- circuit receiver and detector are only getting phone stations on both coasts and from the Texas stations to Winnipeg and Regma. I get all the large eastern and southern stations ; and, while I don't get Los Angeles and San Francisco every night, still I get them a couple of times a week. I use a three-circuit regenerative, short-wave tuner and also a single-circuit 200-3.000 meter «ct. I get these results with either receiver hooked to a two-stage amplifier, the only difference being that the three-circuit set is a little more selective. I use an L type,- two-\vire antenna. 65 feet long, 55 feet high at one end and 35 feet at the other. My hook-ups are standard. Oh. yes! I forgot to tell you: On a three-circuit tuner and W. E. loud-talker I heard Havana teeing. Three others heard this also. — Vernon Wright. Jr, Mauston, Wisconsin. Cage Antenna Popular With some of the continuous wave transmitters of the vacuum-tube type, the cage antenna has been picked by most well-known DX men. Cape antennas are now gen- erally used aboard the battleships belonging to the United States Navy, where some very remarkable results have been recorded by radio men who have worked with them. I PATENTS - aad abnaA CaD or rasa aoviol tsis. u. a. MANjraCTUR'-RS PATENT CO jaj 1 SS0 FIFTH AVC Nf. W 'IB* 32 STATES IN C NIGHTS on l atejU tub* r«c*:»*r imlaM W. Millar's taUM lapravtmanu on hU fiooua lliaaar -Co—b OaU Clivals. MOah Ain.alil far Laaa TSao Sll W. MILLER , ll—MIH MwttMwItt U DALLAS. TEXAS GITHEN8 TRUTONE RADIO HORN— LOUD SPEAKER to aoU oa ten day trial D TOT Wl Bad rraaaaa I* DUtntnUar, and £ AUTO PARTS ISIft lr M. Art). SURPRISED? PATENT To the Man with an Idea I offer a iota ai aba ■«■**• raced, effifwni cWrclopmriM at hia Sand akrtch or aaoM aad tioa. lor adric* at to Uaiaad r My axpancscr and laaiUlarltT with •inooi arta Irrqartitly rub ., to

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30 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? TRY THIS DEPARTMENT AT h A WORD RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department ia intended for everybody who waste quick action on short announcement t covering the baying, settinc, exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that it pays to read these cotaasja every week. Advertisers will get a ten-day service here the* is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy reaches at. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. per word (minimum of 10 words, including address), 10% discount for 4 consecutive insertions, 1Mb for 13 consecutive insertions (3 months). Changes win be made in standing classified ads. if copy is received at this office tea says before publication. RADIO WORLD CO, 1493 Broadway, N. Y. C (Phone, Bryant 4796). PATENTS PROCURED AND TRADE MARKS REGISTERED— Advice and terms upon request. Kobb, Robb & Hill, 1403 Hanna Bide., Clev»- land, Ohio; 942 McLachlan Bldg., Washington, D. C, SUPER-SttdPLCITY CIRCUIT Hear Europe, Asis, Africa and Australia's loos wave stations and LOCAL broadcasting, on ONE TUBE, one control. NO rheostats, storage bat- tery, variocouplere, variometers, three-coil mounting, variable inductance, taps, switches, dead end losses or radio frequency. Cats, hookup, everything. Nothing to guess about. Price $1.00. RADIO EXPERIMENTAL LABORATORY, Box 194A, Berkeley, California. REGENERATIVE RECEIVER, detector and two-stage amplifier, in mahogany cabinets, $50.00. Have received sixty stations with this set, in- cluding Denver and Havana. TED BOSTON, Marion, Kentucky. AMATEURS— LOOK I Send in IS cents to RADIO WORLD for issue of January 20 con- taining panel layout, hookup and full explanatory data on the construction of a D-X receiver, which simply lays the long distance on your table. Or start your sub. with that tissue. RADIO WORLD, 1493 Broadway, New York City. FOR SALE — Grebe CR-8, complete, $75.00; stor- age battery, $10.00; two-step automatic ampli- fier, $25.00. New, guaranteed bargains. Irvln Mauer, Bethlehem Prep., Bethlehem, Pa. WESTINGHOUSE RA Tuner, $45.00. Will trade for Underwood or Corona Portable typewriter. Raymond Schlegel, 1118 N. Negley Ave., Pitts- burgh, Pa. RAND-McNALLY RADIO MAP OF UNITED STATES— Is 28 x 30 inches in size. The locations of broadcasting stations are shown by distinc- tive symbols. The call letters of each station are given, also the wave lengths of each. The Radio Districts with numbers are shown in red and the Radio Relay Divisions are in blue. Time tones are included. Alphabetical lists of stations and alphabetical lists of call letters are in the margins. Convenient pocket form with cover. Price, 35c The Columbia Print, 1493 Broadway, New York City. HIGH GRADE engraving done on your radio panels st reasonable and attractive prices. For particulars, address T. Johnson, IS Rosemont RcL. Worcester, Mass. FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO." Write today for complete list of premiums and our special sub- scription offer. "RADIO," Pacific Bldg., San Francisco, Cat. PHONES, TRANSFORMERS REWOUND.— L Werts, 409 Saint Julian St., Pekin, HI. A COURSE IN MECHANICAL DRAWING— By Louis RooiDion. The author has written a most practical book on the subject of Mechanical Drafting. It fully explains the art of Drawing, lettering and Dimensioning. It is, by far, the most practical book ever published on this sub- ject, for use in day and evening schools, end more especially adapted for the teacher and for self instruction. Fifteenth edition, revised and enlarged. Fully Illustrated. Oblong. COLUMBIA PRINT, 1493 Broadway, N. Y. C Price, tug, HOW TO BECOME A SUCCESSFUL ELEC- TRICIAN—By Prof. T. C Conor Stoane. An in- teresting book from cover to cover. Teurag in Simplest language the surest and easiest way to become a successful electrician. The studies to he followed, methods of work, field of operation end the requirements of the successful electrician are pointed out and fully explained. 202 pages. Illustrated. Nineteenth revised edition. Cloth. Price. $1.50. The Columbia Print, 1493 Broadway, New York City. MAKE MONEY silvering mirrors, all kinds plating, knives, spoons, auto headlights. Outfits furnished. Free booklet. International Labora- tories, Dept. 310. 311 Fifth Ave.. New York. OVERSTOCKED. Must sacrifice DeForest MR- S\ Magna vox, and other goods. Write at once. rjuantity limited. Hober, Radio Co.. Hooart, EXCHANGE JOLLY. INTERESTING LET, rERS through om- crab. Staaaa appreciated. Betty Lee, Inc., 4254 Broadway, New York City. NEWS AND GOSSIP OF THE STAGE— Send 10c. for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $4.00 year, $2.00 six months, $1.00 three months. New fork Star Co., 1493 Broadway, N. Y. OLD MONEY WANTED— $2.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave. 83, Le Roy, N. Y. PATENTS— Inventors should write for Free Guide Books and Record of Invention Bunk be- fore disclosing invention. Send model or sketch of your invention for our Free opinion of Its patentable nature. Radio, Electrical, Chemical, Mechanical and Trade- Mark experts. VICTOR J. EVANS & CO.. 924 Ninth, Washington, D. C RADIO TUNING RODS ~ (Patent Applied For) Eliminates body capacity when tuning In. With Tuning Rod in your hand you can stop unnecessary noises and shrieking. Every radio fan should have Radio Tuning Rod. Send IS cents stamps or money order. Radiophone Co., 505 Fifth Avenue, New York City. SALE— Oapp- Eastham Transformers, 4,000 m.; coupler, sockets, rheostats, Rentier Control Panel, 6-40 Battery; "B" Batteries, Variable condensers, Murdock, Phones, all slightly used. Tubes, new. w.1..10 L°. 25 per cent- off- Kenneth Jones, London Mills, Illinois. SALESMAN wanted in various sections of the country to sell our Supertone Loud Speaker. Retails at $15.00. Liberal commission paid. Plaza Music Co., 20 West 20th St., New York City. , VACUUM TUBE RESULTS WITH A CRYS- TAL SET! Use a "PT" Ultra-Sensitive Contact m your Crystal Detector. Beats gold and other ordinary, catwhlskera. Myrie Wood, Rhinelsnder, Wisconsin, writes: That 'PT Ultra-Sensitive Crystal Detector Contact I purchased fa sure a wonder. Using the 'PT Contact end galena. I have heard over 43 different broadcasting stations, up to 1.000 miles distant." The "PT* has re- ceived over 3.300 miles, when vacuum tubes failed. ,W5!SS5:{TS. cents. "PT' CRYSTAL CONTACT COMPANY, Box 1641, BOSTON, MASS. MILLION „rPOINT TESTED CRYSTALS — Mounted in Woods Metal. These Adbrin Crystals sre tested and are guaranteed or money refunded. With so many sensitive points, it is impossible to miss contact. Stop wasting time and send us 30c for one Adbrin Crystal or send $1.50 for six. mailed prepaid. Also write us for information as we have other styles, including our new type combination twin Galena and Rariedte. DtoHte Radio Panel Boards, insulated, rubber base, cut, bored and drilled with ordinary tools without spoilage. Sizes can be furnished cut to your re- quirements up to 22x21x3/16. Write to us far prices or ask your dealer. DIOLITE IN- SULATOR CORPORATION, 287 New York Ave- nue, Brooklyn, New York. NEWSDEALER TOUR RA7MO WORLD to your home. In order to be sure af getting RADIO WORLD of net ami slug a single issue, we suggest that you eHber suhscilhe a* SMS a yoar (St Issues), D.N six months, and $1-SS three months. Or RADIO WORLD regularly to your home each week, ft— lis wffl i of paper whenever requested. Radio World. MM Broadway, New Yes*. STUCK?— Let me solve your Radio receiving problems. Service charge, 25c per question. Fred- erick Barber, 216 Jasper St, Syracuse, N. Y. HAVE YOU SEEN ITT My unusual lustra ted radio catalog is complete. Only a N. E. Riatey, Spring Grove, Ml~rmirf . MAKE MONEY AT HOME MAKING TOYS and novelties. Send 5c for samples and partjeav lars. New Specialty Co., 417 E. 71st St., New York. EXCHANGE UTTERS with friends everywhere, Pleasant pastime. Insermation for stamp. Smith, Box 3125. M. Portland, Ore. CASH FOR OLD COLD, Platinum, Silver, Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth, Magneto Folate, Jobs, Any Valuables. Mail in today. Cash seat, return mail. Goods returned in ten days if you're not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. WIRING A HOUSE. By Herbert Pratt. «nn a house already built; tells just how to start about wiring it; where to begin; what wire to use; how to run it according to insurance rules; in fact, just the information you need. Directions an- eSS?HZ_to • •h2P- edition. COLUM- BIA PRINT, 1493 Broadway. N. Y. C Prion, STOP PAYING FOR BATTERY CHARGING! Sulphate causes most defects; end your trotmlee De-Sulphate; harmless, guarantees! $1.00 brings you enough for four batteries. In- structions for using. W. L. Green, Monroe CH». Mo. FOR SALE— A large number of 1 step ampEfiera. assembled but unwired. Price $5.25. Also SSJB type Horns Variometers and Variocetrplare. Price $3.25. 43 plate condensers. Price $175. Audio and Radio Frequency transformers. $2JS f» able articles for everyday use. Hints, helps, practical ideas and secret processes are revealed within its pages. It covers every branch of the useful arts and tells thousands of ways of makinaT money and is just the book everyone should have at his command. The pages are filled with mat- ters of intense interest and immeasurable prac- tical value to the photographer, the perfumer, the painter, the manufacturer of glues, paste*! cements and mucilages, the physician, the drear- gist, the electrician, the dentist, the engineer, the foundry man, the machinist, the potter, the tanner, the confectioner, the chiropodist, the ufacturer of chemical novelties and toilet aratJons, the dyer, the electrepUter, the em „ the engraver, the glass worker, the gold-beater! the watchmaker, the jeweler, the ink manufac- turer, the optician, the farmer, the dairyman, the paper maker, the metal worker, the soap maker and the technologist in general. A book to which you may turn with confidence that you will find what you are looking for. A mine of information up-to-date in every respect Contains sn im- mense number of formulas that everyone emght to have that are not found in any other work. New edition. 807 octavo .pages. Cloth binding. Price. $4.00. The Columbia Print. 1493 Broadway. Digft7ze"byVj06g'iC

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RADIO WORLD Orange Label Tea Special lOtTins Choice tea restful relaxation! See that your family is served more of this superior tea; a golden beverage that has a fragrance and flavor — supreme. Also sold in 1 lb., V2 lb. and V4lb. TINS i will be »ent on request. Address: Ridgways, Inc., Department K, 60 Warren St., New York. 5KS? V COLD MEDAL San Francisco 1915 GRAND PRIZE SanDiedo 1916 Digitized by Google

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NATIONAL RADIO INSTITUTE Dept. 43 A, 1345 Pennsylvania Ave, N. W„ Washington, D. C Digitized by Google

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pider-Web Tuner. See Inside 15c. a Copy February 10 $6.00 a Year 52 Numberi WOP L D ILL US TRA TED WEE K L Y . 5- Year-Old Boy Tunes and Connects Radio Set Unaided (C. Underwood & Underwood.) Master Russell Scott Worthington, age 5 years, who tunes and connects radio apparatus unaided. Master Worthington, who is an ardent radio fan, is so interested in radio that he knows how to operate his father's set, and frequently does so. The set shown in the picture was exhibited at the Model Beginners Exhibition, in which all the exhibits were made by the exhibitors themselves. The interest that is taken in making your own apparatus frequently is responsible for many model makers abandoning the regular model ideas and beginning on radio, where they have an unlimited scope for their idea. The plug on the panel of the tube is for use in connection with a crystal detector in case it is wanted.

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RADIO WORLD THE GENUINE AND GUARANTEED "All Wave" Coupler TRADE MARK Wave Length, 150 to 3,000 Meters DO NOT BE CONFINED to listening In on the nearby station* when the "ALL WAVE" COUPLER in your set will enable you to listen in on broadcasting stations THOUSANDS OF MILES DISTANT BE PREPARED FOR THE HIGHER WAVELENGTHS THAT HAVE BEEN AND WILL be allotted to broadcasting stations because of tbeir ever-increasing number. COMBINES SIMPLICITY OF ASSEMBLY with EFFICIENCY OF RESULT inasmuch as it eliminates all Variometers, Variocouplers and Loading Coils. Guaranteed with an absolute money back to operate as advertised. Price $9.0 • EFFICIENT HOOKUPS SENT UPON RECEIPT OF U CENTS TO COVER COST OF MAILING. Capitol Phonolier Corporation 60 Lafayette New York SlIty Standard Radio KSGg AH Goods New, in Original Packages RELIABLE MERCHANDISE FIRST, THEN PRICE SOME OF OUR BARGAINS SETS TUBES W. D. 11— 1% Volt f«-50 V. V. 800 Radlotron 4.00 IT. V. «01 Radlotron Navy V. Tl- J-50 Navy V. T*- '•*» 201A "•«» DeForest s'5 PHONES $16.00 Baldwin Type C 4800 ohms... $9.00 8.00 Holtzer Cabbott 2200 ohms 4.28 5.00 Murdock 2000 ohms 8.00 Federal 2200 ohms J.fO 6.00 Bannard 2200 ohms 8.75 8.00 Dictograph 8000 ohms us VARIOMETERS |6.00 Baldwin *J-JS 9.00 "Capitol" All Wave '.50 8.00 Bmco Moulded o.TB 8.00 Helman Moulded «•«> .5.00 Pathe Moulded Couplers to Match VARIABLE CONDENSERS 88.00 28-PIate Plain «L2* 5.00 48-Plate, A. B. C 2.50 4.00 2S-Plate, A. B. C 2.00 6.60 24-Plate Vernier 4.75 7.70 46-Plate Vernier S..5 .0005 DeForest Balanced «•« Others RHEOSTATS $1.00 Framlngham 1.25 Amsro 1.50 With Dial 8.00 Radio Corp 1.00 Cutler Hammer LOUD SPEAKERS $20.00 Dictograph 25.00 Cleartone »•«* 45.00 Magnavox »*.oo 22.50 Baldwin l4-w $ .50 .75 .75 2.25 .80 $130.00 Grebe CR. 9 $100.00 112.00 M. B. 6 DeForest 90.00 175.00 (Firth ".00 150.00 Paragon u5?? 25.00 Polak Green Crystal 10.00 "B" BATTERIES $5.60 45-VoIt Bveready 8.00 «2tt-Volt Bveready 2.20 5.00 45-Volt Franco 8.00 8.00 22V6-Volt Franco STORAGE 110 Hour Bveready *17,55 90 Hour Bveready 10-00 TRANSFORMERS $5.00 Acme W-»J 7.00 V. V. 712 5-M 5.50 Coto Coll J '* 5.00 Parent S-80 4.50 Thordarson *-00 8.75 Marie 3.00 RADIO FREQUENCY $3.00 Owl »L10 5.00 Meyers 4.00 5.00 Acme *M 4.00 Erla 8.00 SOCKETS $ .75 Turney » •*» 1.00 DeForest 80 8.00 Triple 1-25 .75 W. D. 11 40 1.00 W. D. 11 «5 Others $3.00 Brach Arrester $2.10 2.60 Brach Arrester 1.60 Magnet Wire, Jacks. Plugs, Atwater-Kent Honeycomb Colls, Switch Levers, Potentiometers, Attachments Snnce will nof permit us lo list all our special values, therefore tee Kill gladly space «^»o(e ^,ecio, pricet on any Radio Parts or sets you may want. Reliable merchandise first, then price. We win rotund, at any time, for Radio material mSchVsed from u. which is not up to standard end a. represented, material pure Add p.rcel Post. Reference: Radio World. 577 MYRTLE AVENUE. Phone Prospect 2952-6168. BROOKLYN, N. Y Unit System Is Good Eventually the experimenter will be weaned away from his too-often crudely made set and will have a desire to own an outfit which can be shown with pride to visitors, says the New York Globe. One course to follow is to purchase a cabinet set in one or two large sections. The other is the acquisition of units from which a complete receiver may be assembled. The unit system has certain advantages. With the unit system the purchaser starts with the simple outfit which his purse will afford. It may be only a variocoupler and tube detector. On each unit there are but a few binding posts, usually four. The aerial and ground are connected with two of the posts on the coupler and then the detector is brought into the circuit by neat connectors looping between the two units. Later on, the set can be made regenerative by adding a third unit, comprising a variometer. An- other set of "jumpers," or connecting wires, and the alteration is complete. If the units are selected from one make, the cabinets will agree in size, shape and finish, and no matter how many are added the effect is always an agreeable one. The one objection to this system at first thought would be the space taken up by a string of individual cabinets. But fortu- nately the units may be piled one upon an- other to economize space. A very neat and efficient station may be put together by pyramiding the units. Amateurs Enter Code Speed Contests at Fair MANUFACTURERS of radio appara- tus and amateur wireless fans are attending the Contests at the Permanent Radio Fair, Hotel Imperial, New York City, which are running from January 29 to February 17. These contests are open to amateurs and no entrance fee is charged. Leading manufacturers are giv- ing radio sets and equipment for the prizes in the various classes. There will be first, second and third prizes and ad- ditional ones for those receiving honor- able mention. The main feature of the competition is the code-speed contest which is held daily from 4:45 to 5 P. M. Radio engineers and experts have been selected as judges of all classes. An "Ad" Plan That Hit Radio Distributing and Auto Supply Co. TEL. COLUMBUS SSM M West Nth Street RADIO WORLD, 1413 Broadway New York City. New York, December Wh, 1*23. so Impressed with your I _ . tising medium that the surges tiro was that we advertise only In RADIO WORLD. Our plan has been, as you know, to take a column one week, giving an Itemized list of atar offerings with prices, and on the following to take but three- or four-inch space, i but one or possibly two special items. Although our store has not a particularly good location, our advertising has not only proved highly profitable but has resulted m snfflrieait mail order business alone to give us a bandsjotna profit from our advertising in RADIO WORLD. Therefore, we take pleasure In telling you that we have found RADIO WORLD to be a moat profitable advertising medium. Very truly yours, RADIO DISTRIBUTING A AUTO SUPPLY CO. B. K. OWEN. Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered as second-class matter, March 28, 1922, at the Post Office at New York, N. Y., under the Act of March 3, 1879.] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 47M. Vol II, No. 20. Whole No. 46 February 10, 1923 15c per copy, $6.00 a year Coast Guard Uses Radio to Keep in Touch with Headquarters By Harold Day (C Harris & Ewing) and smugglers beware I The broadcasting stations. U. S, Coast Guard now get This photograph illustrates a direct from naval headquarters in that zone by installation used to relay the broadcast. THE headquarters of the U. S. Coast Guard is using a unique method for distributing news of its service by means of radio. The tales of heroic rescues at sea by the world famous U. S. cutters are broadcast by means of the ordinary telephone connected through the Naval Air Stations at the various naval bases throughout the United States. The method pursued in this . is as follows: In the radio room at headquarters, there is an operator who is always listening in, and any news of the Guards is thereby immediately broadcast direct from the base. The photo illustration on this page shows Captain F. C. Billard, aide to the Commandant, broadcasting, while Lieutenant F. A. Zensler is getting the news right off the ship making the rescue, or chasing the pirate, whichever the case might be. As there is considerable difference in both the wave length of the station broadcasting and that on which the news is received from the cutters, there is no interference. The method of broadcasting is much the same as that used when a con- cert is to be broadcast from a con- cert hall. A special land wire is connected to the larger station, and the operator at the receiving end, through the agency of a regular telephone, broadcasts the message. This also allows the department to keep in constant touch with the various cutters lying off the coast and to give orders direct from naval bases to fleet commanders. Digitized by Google

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4 RADIO WORLD A New and Novel Spider- Web Tuner ON the whole, spider-web tuners are not as popular with the radio amateur as they ought to be. Perhaps this un- popularity is due to the reluctance of the amateur to desert the easily made single layer solenoid coil, but the fact remains that while the sole- noid coil is eagy to wind, it does not do the work as it should. Seeking «scTto*% tn all Fig. 1— Sketch and dimensions of the diacs needed for the construction of this tuner. Also an Indication of how to begin the w iodine. for more compact forms of induct- ance with the maximum of efficien- cy, experimenters evolved the honeycomb, the bank-wound, stag- ger-wound and "spider-web" coils. Waiving discussion of the others, this article confines itself to the construction of a "spider-web" tuner, one that has been adapted to the needs and purposes of even the "fussiest" radio enthusiast. Two novel and original features distinguish this tuner. These fea- tures add heaps to the efficiency of the coils without adding to their constructional difficulties. Having the necessary three coils, for exam- ple, all containing widely different numbers of turns, wound on the same size form is an improvement which will appeal to any one who has discarded spider-web tuners on Fig. 2 — ThU new "duo-vertical winding ia easy to follow and w good as it looks. By Arthur S. Gordon account of the great size of the largest coil. This is one feature. The other is the universal motion of the movable coils, that is to say, they not only move toward and away from the stationary coil, but they also swing to and fro in front of it, like the pendulum of a clock. Spider-web coils are sometimes called pancake coils, because they are wound in circular lines on a flat form. Sometimes the forms them- selves are called pancakes. In the tuner described herewith, four pan- cakes are needed, one for the prim- ary coil of 35 turns, one for the secondary of 50 turns and the other two for the specially wound tickler coil, containing 80 full turns. These pancakes are made prefer- ably of hard rubber, bakelite, for- mica, radion, or any good composi- tion sheet. The thickness is not par- ticular, but should be more than inch. Heavily shellacked card- board, while not the best material in the world, will serve. The four discs should be cut 5 inches in dia- meter and each drilled in the center with a J^-inch hole. Mark the primary disc "A," the secondary "B" and the ticklers "C" and "D." Each form is to be divided in nine sections, separated by saw-cuts as shown in Figure 1. In the case of disc "A," the center is to be 2 inches in diameter ; in "B," the center is to be 1 inch in diameter, while in "C" and "D," the tickler coils, the centers are to be \l/2 inches. These dimensions have been carefully worked out so that each disc will take just the number of turns it is designed for. Using No. 22 S. C. C. copper wire, wind 35 complete turns on form "A." Holding the disc so that the mark is facing you, wind in a clock- wise direction, that is, from left to right, or with the figures of a clock. Weave the wire in front of and be- hind the cut out sections alternately, as in Figure 1. To help in beginning and ending the winding, drill or punch two small holes in the form, suitably placed. For 35 turns of this disc there will be required 29 linear feet of wire. Disc "B" is also wound in a clock- wise motion, with the mark on the form facing you. Because the inside diameter is an inch smaller, fifty turns can fit on this disc with ease. Forty-four linear feet of wire are needed. If the 80 turns required in the tickler coil were wound on a single form, the disc needed would meas- ure 7y2 inches in diameter. To avoid having such a coil, experi- ments were conducted with "duo- vertical" or co-wound coils, with the result that such a winding was found to be utterly practical and highly efficient. It not only cuts down the Fl«. tratfnc the sal of the of maun tin k for the coils is size of the coil and increases the ability of the tuner, but it also opens up a new field for amateur endeavor by opening the path to better and better tuning devices in our radio receivers. Take discs "C" and "D," put them side by side on a temporary shaft so that the marks are facing you. and insert a J^-inch washer between them for spacing. Begin winding as before on the disc nearest to you and make one complete turn Then, instead of continuing on that disc for the second turn, cross over to the other form and make one com- (Continudd on next page) Bar Fig, 4— Side view of the coupler showinf MW in which it is mounted on the paneL Tb tickler Is stationary, bens; fastened to ths Digitized by Google

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RADIO WORLD S (Continued from preceding page) plete turn on it, still keeping the marks facing you and winding in a clockwise direction. Then come back to the first disc, make a second turn, return to the other form and so on until eighty turns, or 70 feet of wire, have been wound on the double form. (See Figure 2.) In buying wire to make this tuner, Yt lb. of No. 22 S. C. C. will be enough and to spare. This duo-vertical winding de- scribed above is easy. The only point about which to be careful is to see that if the wire crosses in front of a section on one turn, it crosses in back on the next. In other words, keep the spider-web idea firmly in mind. What you are doing in this new form of winding is merely making two spider-webs side by side. Soak the three coils in hot paraf- fine. Then turn your attention to the cabinet and to the suggested means of mounting the coils so as to form an efficient tuner. I believe that I am not alone in thinking that the movable coils in a vario-coupler should move in more planes than one. In other words, the coils should be mounted so that they can not only swing to and fro in front of the stationary coil, but also toward and away from it at the same time. The simplest and easiest way to affect this universal movement is shown in Figures 3 and 4. Figure 3 looks down on the assembled tuner from the top of the cabinet, while Figure 4 gives a side view. It is seen at once that the heaviest coil, which would manifestly be the hard- est to handle on a knob and shaft, is stationary and placed well near the back of the cabinet to make room for the other coils. This heaviest coil is the "tickler" and it is so mounted that the marks "C" and "D" are facing the panel. Latest Additions to Dry Cell Tube Family (C. Kadcl & Herbert) Two m opiroti am on* dry call are tlM latest radio at ttHupte OitbhAliM U. V. aU, • dry ■aj— Of wall u dHoctoto or Thojr an tho : U. V. M. aa a—jMBar Not la tha Not U 6m U, V. m. which of tha o-vok tab*. In fact, all three coils are facing the panel when the tuner is finished. Being careful in this regard insures that all the turns are going in the same direction. The primary (coil "A" of 35 turns) is next in line. It is fastened to a brass tube by means of a heavy brass strip, y2 inch wide. This brass tube fits over and slides on a brass rod, which reaches from a little in front of the panel to the back of the cabinet, where it is bolted to keep it in place. At the end of the tube is a knob. By turning this knob, the primary coil is made to swing; by pulling or pushing on it, the coil is made to approach or retreat from the tickler. That's the way to mount a tuner, what? The secondary is mounted the same way, the brass rod which Fbj. «— Two hookup* wM wklck rj*. thro* ob- serves as a slider being 2yi inches away from the similar rod for the primary. Here again we have the universal motion. It is evident, however, that with- out a pressure of some sort to keep the coils in place, they would hang vertically from their respective rods. Such pressure is provided by a ten- sion spring, details of which are shown in Figure 5. It needs no fur- ther explanation, excepting to say that spring brass isn't absolutely necessary, although desirable. A good heavy piece of plate brass will do. The spring is mounted, as shown in Figures 3 and 4. In using a three-element tuner for the first time, place all the coils in line about an inch apart and turn on the filament of the tube until re- generation sets in. Then adjust the variable condenser until you hear the carrier wave of a CW transmit- ter, code or phone, as the case might be. Then move or swing the coils — first the secondary and then the tickler, until the maximum strength and volume of signal are reached. Then clear out the interference with the rheostat or variable and the code or speech ought to come through loud and clear. This tuner may be used in a great variety of hook-ups, and in connec- tion with either the six volt or the volt and one-half tube. For the convenience of the amateur, two suitable regenerative hook-ups are given in Figure 6. RacSo World, 52 u Sobtcrib* dfract mr tbroocfa yam oowadaalar. |&M a yoar, $&M an month*, fl-5t tferaa World, 1413 Broadway, N. T. C Digitized by ™ )OQle

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6 RADIO WORLD National Radio Chamber of Commerce Plans Nation-Wide Campaign SWEEPING reorganization of the Na- tional Radio Chamber of Commerce, linking up, as active workers in a nation- wide plan to wipe out the evils of broad- casting and to solve other radio prob- lems, every major interest of the radio industry and the public, is announced by President William H. Davis following a meeting of the Board of Governors at the Chamber's headquarters, 165 Broadway, New York City. The governors adopted a new consti- tution providing for the admission to membership, either directly or through regional chambers of commerce, of indi- viduals, including the audience or the lis- tener, manufacturers, jobbers, dealers, broadcasters, amateurs, the press, and or- ganizations and institutions interested in radio, comprising educational, scientific, religious, civic, political and other bodies. "Interference and the broadcasting of the trivial and the valueless have injured the business and unless remedied may ruin it," it was declared in a report of a special committee appointed to conduct a survey of* the radio situation and to recommend changes in the organic struc- ture of the chamber, whose membership at the outset consisted of manufacturers. The committee was composed of Henry T. Hunt, general counsel of the chamber and late member of the Railroad Labor Board; George Lewis, secretary of the chamber; and Ralph C. Watrous, former Lieutenant-Governor of Rhode Island. Support and improvement of broadcasting in co-operation with the United States Government and other agencies were said to be the main object of the chamber. "The Government of the United States is interested in radio from the standpoint of national defense and public welfare," said the report. "Furthermore, radio is a public utility of interstate commerce. "Congress has before it the White bill which gives the Secretary of Commerce power to make regulations controlling broadcasting. This, bill may be enacted into law within six months. When the secretary shall have placed proper regu- lations in effect, interference will doubt- less be reduced. However, neither the bill nor the regulations contemplated pro- vide any support for broadcasting or any measure to improve its quality. ' The committee found that there were many classes of activity in the radio in- dustry. Broadcasters were ranged "be- tween the profit seekers and users and belonging partly to both" in the report, which added: "The broadcasting class comprises man- ufacturing companies broadcasting to support and extend their sales of appara- tus, department stores broadcasting for advertisement, newspapers broadcasting for advertising and news purposes, schools, colleges and universities broad- casting for educational ' purposes, churches, co-operating with broadcasting stations, individuals broadcasting 'for their own amusement, and the broadcast- ing activities of the American Telephone and Telegraph Company carried on pri- marily as research and in preparation for whatever the future may develop. "There are at present ineffective or- ganizations of broadcasters, ostensibly rational in scope, but not including the principal broadcasters, as, for example, the Radio Broadcasting Society of Amer- ica, which includes some thirteen or more small broadcasters. In this field some sort of cooperation is compulsory in the nature of things. Further cooperation has been brought about by the Depart- ment of Commerce." Under the new constitution, both the membership and the aims of the chamber, now organized to function as a great cen- tral force in radio control and regulation, are broadened, according to a statement issued through President Davis, which said: "It must be obvious that radio is to become a public service of the highest importance to the nation, both in peace and war. Therefore, an organization de- signed to further its development and co- ordination should be democratic, inclu- sive of all branches and representative of each section of the United States." A vital element in the chamber's plans is the establishment of regional radio chambers of commerce in the principal cities of the countries to be coordinated with the national chamber in New York and with local chambers. Kenneth P. Gregg, one of the engineers and managers of the chamber, reported that steps had already been taken to or- ganize chambers in the middle west and that local interest in national radio or- ganization was developed, particularly in Chicago, Milwaukee, Minneapolis and St. Louis. _ Many groups interested in radio, including colleges and universities and the churches, he said, were studying plans for cooperation withthe chamber, which, he asserted, "is destined to be a tremendous force in promoting the general welfare of the radio industry and through it that of the radio public." The chamber, Mr. Gregg said, was co- operating closely with Secretary Hoover in the Department of Commerce efforts to nationalize the radio industry and with the movement sponsored by the Confer- ence on Radio Standardization. Broadcasting map, 15c. That is, a complete broadcasting map appeared is Radio World, No. 8. dated May 20. Mailed on receipt of 15c. Radio World Company, 1493 Broadway, N. Y. C Never Out of Hearing Now (C. Underwood and Underwood) It is not necMitry for dad and mother to worry, when Sally Sovereign and "Cyclone Billy" Sovereign, of Bay City, Mich., go on an afternoon'* canter. When they are wanted at home, lather J net pick* up the transmitter, and calls them, by means of the compact recelvm* sets with which they are equipped. Dad, by the way, is an ardent fan. Secretary Week's Defense of Harbord Is Endorsed Secretary Weeks' defense of General Harbord, recently retired and made presi- dent of the Radio Corporation, has been endorsed by many officials. General Har- bord's services to the Government as head of the American commercial radio service in the event of war would be invaluable, and the Government should not begrudge him his retirement pay, which some Congressman would cut off. As amended, the Army appropriation bill provides that no officer, retired or in active service, employed by an organiza- tion doing business with the Government shall receive any of the funds it carries. General Harbord, as well as many offi- cers in similar circumstances, would, if the amendment passes, receive no retired pay. A study of the business conducted be- tween the Signal Corps and the Radio Corporation reveals the fact that scarcely any business has been transacted for sev- eral months. Since the war it was not more than $300,000 worth, when this or- ganization was the only bidder. Today, however, the Signal Corps deals directly with the General Electrical, Westing- house and other manufacturing compa- nies, although the corporation reserves the right to bid. During the calendar year the Signal Corps purchased electri- cal equipment valued at $1,475,000.

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RADIO WORLD 7 Radio Instruction for Army Now Fully Standardized By Carl H. Butman WASHINGTON, D. C, Jan. 29.— Radio has a very important part in the education of Army officers in communication, instruction in which important subject has recently been standardized. A definite program of instruction in radio, as part of the schooling of all Signal Corps officers and other officers assigned for training from the Regular Army, National Guard, Reserve Corps and Civilian Military Training Camps, has been laid down by a Board of Army Officers. The board, headed by Col. H. B. Fiske, and including Major S. M. Waltnsley, Signal Corps, recently filed its report on Army Service Schools, including the Signal School at Camp Vail, N. J. Three communication courses are prescribed: The company officers' course, an advanced tactical and administrative course and an advanced technical course, all of which include the sub- jects of wireless and "wired-wireless." The course for company officers includes approxi- mately 1,309 hours of study for Signal Officers and 1,285 hours for officers of other arms. Courses extend over a period of nine months, commencing in September. Radio telegraphy and telephony covers a period of 180 hours and includes theoretical and practical instruc- tion in fundamental electrical principles, spark sets, thermionic vacuum tubes, continuous wave sets, antenna systems, wave meters and other auxiliary apparatus, with special attention to Army radio sets. Tactical radio procedure is studied during 20 hours. This in- cludes the principles governing the organization and operation of tactical radio nets for all arms, and the procedure essential to successful net operation. Other subjects pursued by the student officers include codes and ciphers, combat, orders, electricity and magnetism, wire communication, code practice, message centers, etc. Advanced studies in radio are prescribed in the tacti- cal and administrative course for signal off icers assigned to units larger than divisions. This is also a nine months course and covers study and instruction periods totaling 1,235 hours. The subject requiring the greatest time is the development of signal equipment, which covers 300 hours. Radio systems of divisions and larger units requires 150 hours, and includes instruction on the tactical uses of the various radio sets furnished to Army combat units, the organization of such sets into nets and their operation. Instruction in the prep- aration of orders to signal officers of divisions, corps and armies such as the allotment of wave-lengths, call letters, and special sets is also given. Fifty hours is designated for the study of codes and ciphers, their design and solution. Communication engineering, technique, equipment, design and development, is taught in the advanced tech- nical course. During a total of 1,300 hours, divided into right subjects, these technical officers receive instruc- tion in vacuum tube theory, design of radio, equipment and other apparatus as affected by military conditions in the theatre of operations, construction and installa- tion of radio systems for large units, and specific tech- nical communication problems. Fifty-six officers and 200 enlisted men are now study- ing radio at Camp Vail. Thirty-five are officers from various corps. 15 Signal Corps students, two Marine Corps, two Philippine Scouts and two Cuban officers. The enlisted men are studying to become operators and electricians. After a year's operation, the Army Radio Service has now reached the point where it is operating on a pay- ing basis, giving good service on all official commun- ications in and out of Washington. While perhaps not comparable to commercial radio traffic systems, the Sig- nal Corps radio traffic curve, the plotting of which began in January, 1921, has risen by about a thousand dollars a month. In December it reached the value of S6.200 for the month. This is solely on official War and other departmental radio traffic between stations of the Army Radio Net ; the Army handles no commercial or naval messages. During December the returns for traffic handled, when figured at commercial rates, exceded the costs f«r personnel and maintenance of the whole net, including sixtv stati- >ns. From Another Angle W. C Caffrvr, E. E„ 7t Wukfafta St. Rao, Nevada. IN your issue of Jan. 6, 1923, you de- scribe and illustrate a hook-up by C. White. I have been using a hook-up very little different from this almost contin- ually for the last few months with splen- did results. I get San Francisco, Los Angeles, Portland, Vancouver, Seattle, Calgary, Regina, Salt Lake City, Denver •nd Phoenix almost any evening. Sev- eral nights ago I got Minneapolis. Get local stations without aerial. My aerial is 4 wires, 120 feet long, 70 feet high; radius of reception, 1,000 miles; elevation of Reno, 4,500 feet ; tuning done with .001 variable condenser, using a receiver, which is absolutely necessary. Variome- ter in plate circuit regulates loudness. Enclosed is a sketch of my hook-up. using two stages audio-amplifiers. This in connection with a 14-inch Magnavox. fills the house with music. ^^p.SOor IS Turns Honeycomb /fmpTuAe 001 Hf '-90 V 'B*Bortery-t6f ' Volts on Detector Haokup with which Mr. Caffrar baa obtained aplandie mutt*. Note atattoaa baars by Mr. Caffrar with this circuit. Digitized by Google

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8 RADIO WORLD The Design of an Inexpensive Wave Meter By C. Whitt , Consulting Engineer A SCIENCE cannot advance ' any faster than the progress t. made in the perfection of its measuring instruments. It is very good to calculate, but it is essential that check measurements can be made to verify these calculations. In the field of radio measurements the wave meter stands supreme. Its uses are many, and the amateur who has one can constantly be per- forming many interesting experi- ments with his set. Along with the wave meter is the high frequency buzzer as an exciter. The two should be in the possession of every amateur who wishes to perfect his set in every detail. There are as many types and designs of wave meters as there are voltmeters and ammeters. The heterodyne or "zero beat note" method of measuring wave-length is looked up to as the most accurate and is used exten- sively in radio laboratories. For the average amateur the completion of such an outfit in his own home would be a difficult task, but the con- struction of one of the more ele- mentary types is within the skill of all. Next to the joy of actually mak- ing the wave meter comes the pleas- ure and satisfaction of being the designer of your own outfit. I shall endeavor to give a few outlines first as to the method of Mesign. As shown in Figure 1, the wave meter is nothing more than a tuning cir- cuit containing an inductance in the form of a single layer solenoid, and a variable air condenser shunted across it. The crystal detector serves as a rectifier for the high- frequency waves, while the phones act as audible indicators. When the wave meter is in resonance with the circuit, the wave-length of which is to be measured, the maximum signal will be heard in the phones. Of course, if the meter is used to measure natural wave- lengths of circuits a buzzer will be necessary to excite the circuit, as shown later on in this article. The tuning inductance is fixed. The first thing to determine is the size of this inductance. Wind about forty or fifty turns of No. 22 D. C. C. magnet wire on a three-inch tube made of some good insulating fiber, taking care to keep the turns as close to- gether as possible. After the coil is made one can actually determine by measurement and count the number of turns of wire per inch of length, which quantity we shall designate by the term N. Next, one can also measure the length of the winding in inches, which we shall call L. The diameter, D, is three inches, since we chose to wind on a three-inch tube in the first place. The ratio of D/L in our formula shall determine the constant K, the value of which we can easily get from the table be- low, since both D and L have been previously determined. Ratio: D/L K 1/20 (.05) or less....'. 25 1/2 (.5) 21 1/1 (1.0) 17 3/2 (1.5) 15 2/1 (2.0) 13 3/1 (3.0) 11 4/1 (4.0) 9 If the ratio of D/L should lie be- tween two of the values given in the table it is a simple matter to es- timate. Say, for instance, that the ratio was 1.25. This value lies half way between 1.0, for which K is 17, and 1.5, for which K is listed as 15, therefore for 1.25 it would be close enough to assume K as 16. Now, with everything known or previous- ly calculated, the value of the induct- ance (I) in micro-henries is found from substituting in the formula: KxD*xN2xL 1= 1,000 After the fixed inductance has been constructed and its exact value in micro-henries has been calculated from the formula, the amateur should obtain an air variable con- (Continued on page y) Schematic drawing of the wave meter a* de- scribed In the accotn- panyinf article, b order that the constructor may have aa little trouble a* poaafble la the maldnf of die wave meter, the In- ductances have been worked out for him m the article, and fixed Indue- tancea are used. Thi« simple wave meter cam also be used as a small receivinc set, aa it b completo in every way. Take care that the leads are not looea. Solder every one that is pos- sible. If cars is taken in the construction of this instrument, it will function with surpris- ing- accuracy. Many people think that the calibration of a wan meter is a very techni- cal Job, but by follow- in* the simple instruc- tions in this article, it will not be found so bard, if the person can read equations. Digitized by Google

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RADIO WORLD f Londoner Gets WGY on Two- Foot Loop (Continued from preceding page) denser that has a maximum capacity of .0005 micro-farads. Purchase the ordinary air variable condenser with circular plates that mesh circularly. By that I mean a variable condenser whose capacity is directly propor- tional to the reading on the scale indicating the coupling of the plates. For example, when the plates are half meshed the capacity is half the maximum capacity, or .00025 micro- farads. Previously, the inductance has been calculated, and the capacity is directly proportional to the read- ing of the scale of the condenser, provided the 100 mark on the dial indicates the maximum or full coup- ling of the plates. If W is used to designate the wave-length and C is the reading on the condenser scale, the wave-length can be calculated from this formula below: W-^.21VIxC The best way is to make a table of reading on the condenser scale (C) in one column and W in the other. It is not a hard matter to do this and I would suggest that a special type of condenser be used. There are now several makes on the mar- ket that have their plates so meshed that scale reading varies the ca- pacity as the square root of the maximum instead of directly as the maximum capacity. The advantage is apparent from the formula. It will not be necessary to take the square root of the scale reading. It can be used directly in the formula. Since the square root of the induct- ance is constant in value and is known we can simplify the formula under this special condition to in- clude just a constant number times the scale reading of the condenser C. The wave meter can be used as a measure of the natural wave-length of tuning circuits and antennae. The illustration shows the finished wave- meter hooked up to an aerial cir- cuit. A buzzer is used as an exciter for the aerial circuit. The condenser dial is turned until the respon-je in the phones is at a maximum. The reading on the dial is noted and the wave-length can be calculated from the wave-length formula. The wave- length of the aerial should measure up less than that of the desired sig- nal wave-length. The wave meter will easily tell whether this is true and by experimenting with the length of the aerial and with several other types, it is an easy matter to get one that will have a natural wave-length just a little less than that of the desired station. The wave-length of a tuning circuit could be measured up in a similar manner by connecting the output terminals of the buzzer (AB) to the Ant.-Gnd. connections on the tuner. THE challenge palm for the reception of long-distance broadcasting undoubtedly be- longs for the time being to Captain H. J. Round, of the Marconi Com- pany, for his performance on Christ- mas Eve, says E. Blake, A. M. I. E. E., in the 'London Daily Mail.' "Using a six-valve Marconi-phone plus two 'note magnifiers' (i. e., low frequency amplifiers), Captain Round received music and speech from several United States stations. A pianoforte solo broadcast from WGY (Schenectady) was received at his house at Muswell Hill, N., fairly uniform in strength and of about the same audibility as the Manchester Broadcasting Station, also .received at the same place. "Two facts in particular render this result remarkable. First, the aerial employed was a frame 2 feet square ; that is quite a moderate size for a frame aerial, even for amateur use, and I wish Captain Round would measure the electromotive force it acquires from the Schenec- tady generator, for it must be easier to measure than to imagine. Also I should like to know whether he elected to sit up to the small hours with that pathetic little frame out of pure optimism or because he had what Schenectady would term a 'hunch.' "Much trouble was experienced as the result of jamming by har- monics from Leafield, Oxfordshire and Northolt, Middlesex, which sta- tions are evidently competing keenly with each other in the 'jam' trade. Hence, amateurs will do well to ghre further study to the possibilities of frame aerials, for these, will enable them to escape a certain amount of interference. "The other interesting fact about Captain Round's Christmas Eve- Christmas Morning vigil is that there was no mere 'pig's whisper/ but a loud-speaker in full blast. Now one needs quite a respectable volume of sound to make a loud- speaker shout about the house, so that although eight valves were at work the result is really surprising and should give a fine fillip to ama- teur endeavor. I may mention, for the benefit of those who wish to repeat the experiment, that the wave-length on which WGY was sending was about midway between those of the Manchester (385 metres) and Birmingham (425 metres) broadcasting stations, and that the signals were heard before 2:00 a. m. (Greenwich)."

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10 RADIO WORLD Don't Try to Reclaim Dry Cells By Arthur S. Gordon A SEARCH for practical and useful information con- cerning the 1J4 volt, No. 6 dry cell, now used by radio amateurs in lighting the filament of the DeForest dry-cell tube or the W D 11, resulted in some interesting but disappointing "dope." The person who made the in- quiries wanted to know, first, if anything could be done to prolong the natural life of a dry cell, and, second, whether suitable dry cells could be made at home by a radio amateur in average circumstances. To give the answers to these questions, the inquirer in- terviewed the men behind the radio counters in big stores, electricians, mechanics, engineers and tradesmen — in fact, everybody within a ten-mile radius who knew, or who was supposed to know, anything at all about dry cells. The men behind the radio counters slumped visibly when questioned on dry cell construction and practical operation. They just "handled" the batteries. But they knew what was expected of the batteries in the way of voltage, and were willing to put them to a short-circuit test with a voltmeter. Most of them were advised that a radio amateur insists on this being done. "Wise clerks," they said, "will do it without being asked — merely for their own protection." Occasionally a dry battery that has never been used fails to register a current. AH of them are marked with a "shelf limit" date, which is generally set for about four months after manufacture. After the shelf limit has expired, the makers of the dry cell will not guarantee its performance. Radio clerks usually inform amateurs of this fact, and may even point with pride to the distant hour of expiration on the batteries they are offering for sale. Other salesmen, however, may not be quite so sympa- thetic. Dishonest stores often cover up an expired shelf limit date with a brazen trade sticker telling the customers to "come again." When buying your batteries, then, make it a point to notice the date upon which they technically become shopworn. When a dry cell is idle, that is to say, when it is not electrically connected in a complete circuit, there continues a chemical reaction inside the cell proper, which gradually decomposes the necessary elements for the -generation of energy. Such a reaction is slow, of course, but it is there and it is constant. A dry cell has no storage capacity. Whatever energy generated by a cell while slowly deterio- rating is dissipated at once. This internal action continues long after the battery has been discarded as dead. The zinc covering breaks open and the "mix" bulges out. The battery slowly eats itself away to nothing. In action, a dry cell will not give continuous results satisfactorily. It serves best when used intermittently. While operating, chemical action causes, within the cell, a layer of hydrogen gas to collect on the surface, of the zinc electrode. Hydrogen gas is not a conductor of electricity. Therefore, the coating on the zinc raises the internal re- sistance of the cell to such a high value that almost all the energy developed is used in forcing the current through the cell, leaving but a negligible current for the outside circuit. When the terminal voltage is thus affected the cell is said to be "polarized." In the mixture of the ordinary No. 6 dry cell, there i- what is called a "depolarizing agent." This is black oxide of manganese. It is supposed to clear the zinc of the deadening hydrogen bubbles, but it cannot work fast enough to do its work under strenuous operation. This is why dry cells recuperate with rest — that is, to ascertain limited extent (not as much as wet cells, for instance). The "de- polarizing agent" has a chance to do what it is designed to do. The modern dry cell is an improvement on the old Casner-Leclanche type, but it is not all that it could be. The battery which has the zinc electrode outside is not as effi- cient as one that has it inside. It is the zinc which is the fuel supplying the electrical energy, and it becomes thinner as it is used and finally is eaten in holes. The carbon stick, on the other hand, does not deteriorate. It is a mere col- lector of energy. When a No. 6 dry cell becomes useless, the remaining zinc becomes waste product. In the flat type of battery, now used for searchlights and sometimes for "B" batteries, the zinc may be wholly eaten up, and the battery will discharge energy right up to the disentegra- tion of the last ounce. But it often happens that a battery goes dead when its zinc covering seems to be in perfect condition. The fault seems to be with the mixture, which is not strong enough to produce energy right up to the limit. "What can be done with such batteries?" "Nothing," answered one electrician, who had been re- placing batteries for ignition purposes on Fords. "Tear off the binding posts if you want them, and dig out the carbon rod in the center if it is of any use to you. But throw the rest of the battery away. It has lived its life, and it's through." "Well," answered an automobile engineer, "I never had to practice economy in that direction, but I suppose you could clean them out and fill them up with a new mixture. The only difficulty would be in clearing away the old mix from the zinc. If you have ever opened a dry cell, yon" know how that stuff sticks. What do I advise? Throw 'em away, and buy new ones. They're selling cheap enough!" Nothing very enthusiastic about their comments. But on second thought, it is a sensible attitude to take. As elec- trician after electrician voiced the same views, the radio inquirer adopted the conclusion that an old battery is no good for anything. It cannot even be connected in series or in parallel with a new battery, for instead of contribut- ing its own "wee" current to the combined effect, it actu- ally takes some away from it. The best procedure is to rip the battery apart, take out the carbon stick intact rescue the binding post from the half-eaten zinc and "dump" what is left. Then, if you have an itch for making things, or if you like to think yourself independent of the dry cell market, you might buy the following articles: a piece of zinc, 6 by 9y2 in. ; a half-pint of asphaltum varnish ; an ounce of either nitrate of mercury or bichloride of mercury dis- solved in a quart of hot water; a quantity of heavy blot- ting paper; \l/2 pounds of pebble or crushed carbon; y2 pound of black oxide of manganese ; y2 pound of granu- lated chloride of ammonium (sal ammoniac) ; and % pound of whitewood or willow sawdust. With these necessary materials assembled at a cost of about 75 cents, go ahead and make a dry cell all by yourself, using the carbon you rescued from the old battery — but you can see right off that it can't be done profitably unless one is going into the business on a big scale. No, making a dry cell so that it would save money can't be done. The advice not to try it is given reluctantly, but it is only fair that the new user of dry cells know the worst at once. So much material goes into the manufacture of an ordinary No. 6 cell that only quantity production makes the market price as it stands today even reasonable. Digitized by Google

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RADIO WORLD 11 Using Two Generators for One Airplane Radio Set By S. R. Winters Raar cockpit, skowinc the ml upon which la ImsbJUtioo of traaaatfttau; ItbuMm. Whan la tha ah-.thawwaia 4 B 'plana. NatJca tha Baa id, by — uu of a wabjht, *mpa u aaw aatvaraany aaaa la Tha BMtar bath tha iraan a through tboaa aa tha IN the far western States, where radio and aircraft have formed a coalition as an agency in com- bating forest fires, a departure was made recently in the wireless instal- lations. Contemplating the possi- bility of a breakdown of the device for generating electricity for radio purposes, a duplex system of gen- erators was affixed on airplanes sub- ject to long patrols during the fire- fighting season. Each of these fan-driven gen- erators has a capacity of 4,500 revolutions a minute. This special inductor design alternator is rated from 116 to 125 volts on open cir- cuit, and is a 900-cycle, 200-watt generator. The stator is composed of four direct-current poles, four slots being cut into each of these so that the high-frequency current windings may be placed therein. The rotor has an even dozen teeth and serves as an inductor. The slots between the teeth offer space for placing the direct-current windings for exciting the field. The com- mutator on one end of the rotor de- livers the direct current to the field coils, one side of this circuit being carried to a distributing block to facilitate the connecting in of a field switch and a dry battery. The lat- ter are auxiliary agents for exciting the electric field. The twelve teeth in the rotor, when rotating, pass the alternating-current windings and vary the flux through a dozen cycles for each revolution. As the term implies, each of the two generators installed on this fire-fighting aircraft is driven by a two-blade air-fan. The speed at which these fans operate is constant, despite wide variations in air and wind velocities. Immunity from the influence of air current is accom- plished by use of a centrifugal gov- ernor mounted at the center of the fan inside the housing of the gen- erator. This governing device va- ries the pitch of the air- fan blades to correspond with variations in the velocities of the upper atmosphere. This centrifugal governor is so ef- fective as to maintain the speed of the generator within plus or minus four per cent of 4,500 revolutions a minute, despite a variation in wind velocity ranging from 50 to 175 miles an hour. The alteration of the pitch of the two blades on the air-fan, the driv- ing force of the generator, is accom- plished by use of two weights, one attached to each blade arm. Their positions are influenced by centrifu- gal force. Such force of the weights is counteracted by compression springs, the result being that when the spring reaction and the weight on the arms are correctly adjusted, the position of the equilibrium be- tween these two opposing forces will be such as to insure a constant speed of 4,500 revolutions a minute, irrespective of the wind velocity. NEEDED BY ALL AMATEURS TABUS, BT FUMBg X BADIO WOaxfc. Ma. M. anal «■». M. N*. I tilth OajftuM WW. ■!■■> Ma. H, OM Do* 1 Ma I ataafc m-OaaawJ Warn. KADIO WOftLD. Ma ' Cmmt* win. BADIO WOMLD. Ma <•. aaaa Da& M art aT t aaaa a* fl aaaa Or r nana] avia aaa» aaaa aoaaac RADIO WORLD. I4» BROADWAY, NEW YORK. M. Digitized by Google

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12 RADIO WORLD Wave Length and Interference IN the adjustment of radio re- ceivers, we know that we can "tune-in" different stations which are transmitting on different wave-lengths by an adjustment of the control or controls provided in the receiver for this purpose. We know that, even though a number of stations are transmitting simul- taneously, if their wave-lengths are sufficiently different we can tune one station out and another in. In order that the term "wave- length" may have somewhat moTC meaning "than that of an arbitrary term, it may be explained that the energy which actuates a radio re- ceiver and which is transmitted through space from the transmitting station, is transmitted in a series of pulses. These pulses are so frequent that they cannot be individually de- tected by the ear, and they generate an electric current in the receiving antenna, their nature being such that each pulse generates a current in the opposite direction from that generated by the preceding pulse. If we can mentally picture these pulses in space at a given instant, between the transmitting and the receiving station, the distance in meters between one pulse and the second pulse ahead of or behind it, is known as the wave-length of the transmitted signal. The majority of broadcasting stations are operating on wave-lengths between 350 and 400 meters, which is very nearly one-quarter of a mile. For long dis- tance commercial radio work, the wave-length is frequently as long as 20,000 meters, or approximately By B. R. Cummings Radio Engineer of General Electric Co. \2l/2 miles. The speed of transmis- sion is so great, however, that, even at this wave-length, approximately 30,000 pulses are picked up at the re- ceiving station each second. For an analogy of what takes place in a radio receiver when it is tuned to a particular wave-length, let us picture a swing suspended from a branch of a tree, say, and that two people, one at each end of the swing's travel, are alternately pushing the swing and keeping it in motion. Their pushes are timed to the natural period of the swing, so that each push is delivered at a time when it will add to the motion of the swing. In this case the energy given to the swing by the two peo- ple alternately pushing it is anal- ogous to the energy put into the radio receiver by an incoming sig- nal, and the motion of the swing is analogous to the current flowing in the receiver, flowing first in one direction and then in the other. If, however, the people pushing the swing do not time their push so that it matches up with the natural pe- riod of one swing, the amplitude of the swing will decrease more and more as the pushes become more and more out of step. We know that the shorter the length of the swing, the quicker it will swing back and forth, and that as it is made longer the time re- quired for it to travel back and forth is increased. . In the case of a radio signal we have no control at the receiving station over the frequency of the pushes or pulses of energy, the frequency being established at The Rolls-Royce of Radio Receivers (C Internationa! Nrwsreel Photos) The super-heterodyne receiver illustrated here has been termed by its Inventor, "The' Rolls-Royce of AU Radio Apparatus." It is a most efficient apparatus of its kind, and like its name it is most certainly not the apparatus for the man with a "flivver" pocketbook. the transmitting station, but we must tune our receiver so that the flow of current in the receiver will be a maximum. When we tune the receiver, it is analogous to shorten- ing or lengthening the swing so that it will have a natural period which will match up with the frequency of the pulses transferred to it, under which conditions the travel of the swing and likewise the current in the radio receiver will be a max- imum. Since all radio signals, re- gardless of their wave-length, travel through space at the same speed, the shorter the wave-length the greater will be the number of pulses received per second. The fact that a great number of transmitting stations can transmit simultaneously on different wave- lengths and that any one of these stations can be received without in- terence from the others, provid- ing the wave-lengths are sufficiently separated, is one of the most inter- esting phenomena encountered in radio. The signals from all of fhese stations exist in space simultaneous- ly, but none of them is affected by the others, each communication re- taining its individual characteristics. Although very incomplete, a simple analogy to this condition can be made by dropping two stones simul- taneously in a still body of water, at a separation of several feet. Waves in concentric circles will emanate from both points at which the stones enter the water. These waves will increase in diameter and the waves set up by one stone will cross those set up by the other, but after they have crossed they will emerge intact and neither one will be distorted or changed in form by having come in contact with the other. , In the foregoing it has been care- fully stated that stations can be re- ceived without interference from other stations "providing there is a sufficient difference in wave length between the station received and other stations." This condition ex- ists usually in commercial work, and did exist until recently in radio broadcasting work. With the in- creasing number of broadcasting stations, however, and the compara- tively narrow band of wave-lengths which have been allotted by the Government for broadcasting work, it is not possible for all stations to {Continued on next page) Digitized by Google

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RADIO WORLD 13 ^Blowing Up a Battleship By Means of Radio (C Kadel & Herbert) One of the latest development! of radio ie the invention of a special radio wave, discovered by Bet-nays Johnson, which will allow a to be exploded at a distance. The special bomb ie not dangerous, as it can only be set off by. a person having the proper apparatus for orating the wave. Photo shows a demonstration in blowing up a miniature battleship. (Continued from preceding page) work on a wave-length sufficiently different from those of other sta- tions to permit its reception without at the same time hearing one or more of the other stations. A study of thjs condition has recently been made, and in one town, which is typical of a great number of the small towns in the eastern part of the United States, a total of thirty- nine broadcasing stations were picked up, in one evening, all oper- ating on wave-lengths between 350 and 400 meters. In many cases two stations were found to be working on exactly the same wave-length, so that, even with the most refined re- ceiving equipment, it was not possi- ble to differenciate between them. Until this condition is improved, those who listen to radio broadcast- ing are subjected to considerable disappointment, for we frequently find instead of selecting the particu- lar program which we wish to hear, we are obliged to accept one which we can get without interference from other stations, this one usually being the station located closest to the receiving station. Superimposed upon this condition # is interference caused by static dis- turbances and by receiving equip- ment in the hands of people not cautious in its manipulation. It should be remembered that, when- ever a vacuum tube receiver is al- lowed to oscillate, it itself becomes a low power radio transmitter and causes interference with reception being carried on in the immediate vicinity. In receiving telephone sig- nals, it is not necessary to have the receiver oscillate at any time, and any operator who carelessly permits his receiver to oscillate is increasing the dificulty of obtaining satisfac- tory broadcasting reception. The elimination of static interfer- ence is, at the present stage of radio development, beyond the hope of the average receiving station and must, therefore, be accepted as an unavoidable evil. Interference caused by other stations will, we hope, be reduced in the near future by the allotment of a wider band of wave-lengths for broadcasting pur- poses. This development has been under consideration by the United States Department of Commerce for some time and we must expect a ruling from them which will al- leviate this condition. Until such modifications are made, however, interference caused by other sta- tions is also an unavoidable evil for the average receiving station. More refined receiving equipment can be built which will increase consider- ably the selectivity of radio receiv- ing equipment, but such equipment is comparatively expensive. This condition will doubtless be remedied in the near future. Until that time we must be content in the knowledge that every effort is being made to improve this situation and that any apparent delay in ac- complishing such improvement is merely an indication of the diffi- culties which are being met in mak- ing it. Digitized by Google

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14 RADIO WORLD Radiation By Washington R. Service OPERATORS of broadcasting stations are warned by the Radio Section of the Department of Commerce not to communicate with other stations by either telegraphy or telephony as broadcasting licenses do not permit direct communication. Some stations have been guilty of ac- knowledging letters, telegrams and telephone calls, which, the Department points out, is direct communication. The suspension or revocation of the operator's license is tlje penalty for infractions of this rule. Owners are also cau- tioned to observe the rules laid down by law else their station licenses may be endangered. * * * The Navy Department has begun the publication of the Communication Bulletin, issued in the interests of increas- ing the efficiency of Naval Communications, especially through greater rapidity and accuracy in handling mes- sages by radio. "Keep the Fleet Mobile" is its motto, based upon the theory that efficient and uninterrupted com- munication between all units of "the Navy makes for mobil- ity of our sea defense. * * * Radio has found its way into a college curriculum, ac- cording to a report from Philadelphia, which states that the University of Pennsylvania plans courses in Radio this Spring. Tulane University, WAAC, is now broadcast- ing the Commerce reports at 7.05 Central time on Fridays. * * * Despite the general use of radio and the millions of fans informed as to the reception of broadcasts, some remain ignorant of possibilities: The other day in the National Press Club, one member suggested that the set be "speeded up," saying the music coming in was "too slow." Bathing by radio is one of the last broadcasts from the Public Health Service, but whether ether waves were rec- ommended was not made known. * * * "Have they -arranged to send money by radio yet?" asked a fan. "Probably not," replied his wife, "too many people would 'pick it up.' " * * * An admiral of the navy, in objecting to the suggested licensing of all service radio operators under commercial regulations, said it would be as sensible to require that he and some 6,000 other navigators in the navy take the De- partment of Commerce's examination for a master's license before they would be permitted to carry any passengers on naval vessels or transports. Which seems to be a good argument. * * * Someone has suggested the name of "Radioowners" for those of us who have sets and listen in. Certainly it is better than most of the awkward terms in use today. "Listeners-in" is too long, "Radiophans" or "Radiofans" sounds like the name of an instrument, and we could hardly designate them as ''receivers." * * * Secretary Hoover says he doesn't care who contro-s radio and is willing to turn it over to the Interstate Com- merce Commission, if Congress so decides, but he does in- sist that some regulations be enacted into law and that some one be put in charge to relieve the interference, handle licenses, and assign the waves. Broadcast Bill's Radiolays JIM KATER, better known as "Slats," re- marked the other day that when it come to checkers he wuz "there" in every way. He talked so much about it that the fellers at the store got so they 'most believed him, all he said an' maybe more. Sez he, "Look! what I done last year ; I'm champeen of the county, fer didn't I beat 'em, everyone, an' romp home with the bounty" The checker tournament this year wuz held in Brussells Sprouts an' endin' yesterday it caused ex- citement hereabouts. Today there's sad- ness in their hearts — I 'spose that some are achin', the boys had picked "Slats" Kater thinkin' he'd, bring home the bacon. Last year with forty entries I beat all of 'em but one. "Slats" Kater took me over but he had to work like fun. Before the game I figered I could win as sure as shootin' but when we started playin' all the boys begun their rootin.' 'That's the ticket, 'Slats,' old boy, you've got him goin' now." I guess it must of rattled me er somethin' anyhow he got the best two out of three an' so I said this year I'd stuff my ears with cotton to make sure I couldn't hear the rootin' that them fellers did when "Slats" pulled off his plays. An' then I had an idee which beat that one forty ways. You know I'm fond of list'nin' on this wireless set of mine, so I thought with those earmuffs on why wouldn't it be fine. I'd hear the sweetest musk of some military band an' then they couldn't rattle me. I guess you undeer- stand. Well, it worked out just like I By William E. Douglas "There's no doubt in my mind Radio's what did the trick." thought, friend "Slats" an' I were tied, so we were matched together, an', folks, that wuz when I tried the scheme which I just mentioned. Say it worked out purty slick an' there's no doubt in my mind Radio's what did the trick. I set there chewin' "Spearmint" with "Slats' " rooters all about an' listened calm an' peaceful fer I couldn't hear 'em shout. Then when I got him cor- nered, gosh I laughed at them big bums. Meanwhile the band wuz playin' "Hail the Conquering Hero Comes." Copyright, 1922. Westinghouse Electric & Manufacturing Company. Digitized byGOQQle

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RADIO WORLD 15 Radiograms The Latest Important Radio News Briefly Told for the Growing Army of Radio Fans FOR the first time in the history of radio, an interchange of messages will be tried between American and French amateurs, without the request for "quiet air." This has been suggested, because of the fact that so many American amateurs were heard in the recent trans- Atlantic tests. If the tests are successful, a new point in low power transmission over long distance will be reached, because it is infinitely harder on the receiver to listen through and successfully get a message when the "air" is full of other stations sending. ♦ * « An address entitled "Police Work" was made recently from station WOR, by Commissioner Enright, head of the Greater New York Police Department, and President of the International Police Conference. As every large police headquarters in the entire United States is now equipped with the most up-to-date radio apparatus, this lecture created a' great interest in police circles. Commissioner Enright is the recognized authority on police work and matters pertaining to it. Special arrangements were made whereby loud speakers were installed, thus allowing hundreds of thousands to listen in to the address. » * * In an address before the Baptist Social Union at the Hotel Astor, in New York City, last week, Roger W. Babson declared that die churches of the country must be included in five or six great groups to be affected by radio broadcasting. He advised church members "to control for all time in the interests of righteousness the greatest single force for good or evil that is known today." "A hundred thousand churches in this country and their millions of members little realize how their institutions are to be changed by radio broadcasting," said Mr. Babson. "People, like water, travel along the lines of least resistance. If they can hear, at home, by the fireside, on the radio the same service that they would other- wise have to go out and hear they are apt to remain at home and use the radio." * * * The general call signal KFZZ has been assigned for all ves- sels the radio stations of which are operated and controlled by the I. W. T. Co. This general call will be used by I. W. T. Co. ship or coast stations desiring to ascertain whether there is an I. W. T. Co. vessel within range, and any I. W. T. Co. vessel hearing another ship or coast station calling KFZZ should answer. This call signal also will be used in broadcasting general instructions to I. W. T. Co. ships. ♦ * * Porto Rico, which began broadcasting late last summer, has been plainly heard at points 2,000 miles distant. Cuba, which has a station of 400- watt capacity, sends out a 400- watt meter wave with a message of 2,400 miles. ♦ ♦ * Radio Regulation Bill is Passed by the House.— The Federal Radio Control bill, which vests in the Department of Commerce the power of regulating all the wave lengths to be used, as well as the direct supervision of all phases of wireless telegraph and telephone communication, was passed in Washington on Jan. 31, 1923. The purpose of the bill js to eliminate the inter- ference that is so prevalent now. Licenses will- be required from all operators, with the exception of Government stations and operators handling government work. The power of as- signing the different wavelengths and licenses is in direct charge of the Secretary of Commerce. The bill provides for an advisory committee of men appointed by the department heads, and will be the most eminent radio experts and radio men in the country. Amateur receiving stations will not be affected by the bill, and amateur transmitters will have a special series of wavelengths assigned to them. Radio and the Woman By Crystal D. Tector I HAVE at least found IT. Or rather we found it, I should say, for I had the help of a friend. We refer to a person who neither knows anything about radio or professes to care. We met her at a social given by the church, and, after a while, the talk turned to radio. "Oh, that silly thing," she exclaimed. "I never thought that normal women would lake the least in- terest in it. My time is all taken up minding the house and children, and seeing that Jack has a warm dinner waiting for him every evening." Well, that certainly was nice. As though I ever fed F. H. on cold cuts, or let the children run around like orphans. * * * ONE of the local theatres in our town has been running a moving picture in which the heroine is saved several times by means of radio. (Of course, she fell in love with the hand- some operator of the station, and married him later.) The owner of the theatre, in order to increase his patronage during the run of the picture, advertised an amateur set contest. The winner was to have his choice of a season pass, or a trip through a modern moving picture laboratory. The only con- ditions were that no one over eighteen years of age could compete, they must have made the apparatus, and must be willing- to allow it to remain on exhibition for a full week be- fore the performance. A young man seventeen years of age won the prize, and chose the season pass. * * * THE fact that radio is really important to a woman who has to stay at home and attend to house duties, was illustrated to both F. H. and myself when we were visiting one night last week. The hostess, during the evening, confided to us the fact that since her husband has bought a Radio set, she doesn't go to nearly as many matinees or afternoon teas but, instead, stays at home, and then is able to keep him in good humor, by having a nice hot meal for hubby when he gets in. "And I've noticed the number of sick friends that he used to spend the evening with are all better. He never goes out now to play the part of nurse to some other man. - And do you know that if I didn't have that radio set, I think I would go to just as many matinees and teas as I used to, and Jack would be just as grumpy, when he has to stand for delicatessen food, as he was formerly." * * * THE minister of our church gave us a little talk the other evening at the meeting of the Ladies' Society, on the way in which Radio has helped the human race in general. After the meeting our pastor appealed to me, asking me if he had made his point strong enough or if I thought it was too strong I thought it was just wonderful, as did all the others. You simply cannot make anything that relates to radio too strong * * * FRIEND HUSBAND, through a friend, heard the news that the concert we heard broadcast from PWX on January 6 was heard in Douglas, Alaska. "Why, they even heard her name, and the piano strike the first chord." The song he was referring to was "Mother Machree," sung by Miss Harriet Williams, of the American Consul General's Staff in Havana. * * * I HAVE just received an invitation to take a trip to England and listen in on the great trans-Atlantic test that is to be tried out next month. A friend of ours who owns a large yacht, tried to entice me by telling me that he would install a private set in my stateroom, so that I could keep "up to the minute" on all the latest radio stunts. No thanks, everything is happening too rapidly over here for me to think of going abroad, especially during the roughest part of the winter. One trip abroad, when we were first married, convinced me that I ne\er was meant to be a sailor. Ill never forget that trip as long as I live. Neither will F. H. Digitized by Google

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RADIO WORLD News of Rac (C Underwood and Underwood) Dr. R. S, Piper, Chicago surgeon, and his single tube radio aet which contain* the only existing patented coupling transformer, which enables the set to receive extremely long distances without amplifiers. The tube used is the papular VA volt tube, and the tuning is all done by means of the single control on the side of the cabinet, and the filament adjust- ment which Is shown. The binding posts on the bottom of the cabinet are for the various battery connections. (C. Kadel and Herbert) (C. Fhotcmews) Radio music as an aid to dancing is the latest use to which radio has been put by Helen Lynch, noted actress and dancer. She keeps in trim for her stage dances by practicing to the tunes sent out by the various broadcasting stations. Since the larger stations have been enabled to broadcast the music of seme of the larger dance orchestras, many new enthusiasts have Joined the army of dancers. (C. Keystone View Co.) Viscountess Maftland, cousin of the King of Eng- land, having her character read by radio in New York City. Mme. Radora claims to sense the vibrations of her subject by radio, through the agency of the apparatus shown. The small pedestal has no connection with the apparatus used, and is used to hold the transmitter into which the questions asked are answered. As everything is secret, the one-, hearmg^wh^s (C Unde The only the iu»I: macs tro such s» « Inside of l

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17 via Camera Captions by John Kent T Sgg-watt, < mittlag- Mt la the recent «• radio station 2ZL, J. O. Senlth. Valley Stream, " nd. Two ZSS-watt tubes an uaad wttfa alternating cur- rant to Heat the filament, aad aba to supply tha aacMaary plato vol tag*, a aaif-racUiyUig circuit berna" uaad to eliminate For lator- rivet, tha , , b mt cantor of tha photograph next to tha feat tube, la used. Thai allow* tha signals to b* heard on either errata! or audion. As straight can oa seen. It consists of high-speed motor with a attached which is altar- pieces of tneuiating nmte- •ad brass. A piece of or springy mstal presasa the wheel, aad when In It hjuniupts the current signals to be (C International Kewtrccl) By an ens of a portable loop aad a loud speaker, train moving under the East River la New York. "Star** were niched up at the Nth Street station of City. John C. Davidson, the inventor, la sittjng broadcast by the Kansas latarhorough it to A a snbua» asas City New York wd Underwood) bat little brother gets to baton in these days Is supper. The owner of this station, no doubt, hi anting- little brother away from the like to fool with things forbid it pUca la the life of today that i wflTbe satin when . sat. Radio has takea ear* the old predicts that The m o' cat and been (C Photoncwi) The two towers of the ad will WJZ, station on tap tha York have yu»t .t».

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18 RADIO WORLD Answers to Readers •Amplifying Transformer, ^m1 'B"Bcrtt^^f•4SV. "== Ground Regenerative receiver using three honeycomb coils, with detector and two steps of amplification, as requested by Mr. Le Croice. (See letter on tide pace.) PUBLISH hook-up using the following materials: 3W-D 11 tubes, B batteries, 2 variometers, 1 vario-coupler, condensers, socket rheostats, etc. What would be the range of the sett Show how I could use two panels — one for the radio frequency, one for the detector and audio frequency. — Charles Scheer, 300 Clifford Street, Phila- delphia, Pa. Refer to Radio World dated Dec. 9, page 4, where you will find two very ex- cellent radio-frequency hook-ups by Don- ald Van Wyck. There is no stated range to any set, but you should have no trouble in getting upwards of 1,000 miles out of such an outfit if correctly connected. Refer to page 13 of Radio World dated Dec. 23, where you will find an article on this by John Kent and Arthur Hen- nesly. * * * 1. Your hook-up published by Mr. Gordon in the January 20 issue of Radio World, states that a 50-turn coil and a 75-turn coil is used, yet the drawing shows' them tht same size, 2. Also, the way in which Mr. Gordon has the panel laid out, maFes it impossible to ro- tate the upper coil, because of its proximity to the lower one, which allows only a very slight movement before they hit. Is this as it « supposed to bet 3. Will regular unmounted honeycomb coils of [ike number of turns do for this purpose in this circuits — C. Z. Hoffman, 1415 Vine Street, Philadelphia, Pennsylvania. 1 and 2. As the exact difference in the coils themselves is so slight it was not shown in the drawing. We left it to the readers to realize that the working drawings meant the respective coils as described in the article. This was an error not realized at the time of writing, but can be remedied by having suffi- cient play in the bearing of the upper coil to allow you to turn the entire coil. It calls for some little extra work but the results gained will repay you many times in re- ceiving. 3. Regular unmounted honeycomb or duo- lateral coils will answer the purpose if the correct coils are used — namely the 50 DL and 75 DL. ♦ * * Publish diagram of a three - circuit regenerative receiver using the following apparatus: 1. Honeycomb coils, separate batteries for detector and amplifier, and two-step amplifier with jack at the end of the second step. Primary circuit to have condenser in parallel for long waves. 2. What meter range is possible with such a sett 3. Can I use it for 360-meter waves as well as otherst 4. What kind of transformers are neces- sary t 5. What kind of tubes should I usef 6. What should the voltage on the ampli- fier bet 7. Can I use a loud-speaker with such a set, the loud-speaker to be in the adjacent room, which would necessitate a lead of wire 40 feet in length f Would this harm the signals in any woyt—Jack Le Croice, 254 Studman Place, Montreal, Canada. 1. Hook-up you request is herewith pub- lished. 2. You can get from 150 to 25,000 meters with such a set. The wave range depends on your coils. 3. You can use it for 360. 4. Any audio frequency transformer on the market is O. K. We advise a high ratio transformer for the first tube so as to get the maximum transfer of current from the detector through the first stage. 5. A W-D 11 can be used with this hook-up, as a detector (the detector bat- tery being separate from the amplifier). Hard tubes of the U. V. 201 type should be used for the amplifiers. 6. The voltage is marked on the draw- ing. /. You can do as you suggest if care is taken to make the wires no longer than absolutely necessary. Good results can be had by using twisted lamp cord. No harm is> done to the signals, but they might be slightly weaker, due to the resistance of the extra length of cord. 1. Can the Meyers' tubes be used in the set described in your issue of Radio World dated January 20 by Mr. Ortherus Gordon t 2. Can I use the Meyers' Audio Choke coil for one stage of amplification in con- nection with the foregoing t 3. In winding the honeycomb is it neces- sary to wind it as lattice or can straight winding be usedf 4. Can I use the standard honeycomb or D-L coils with this hook-up t — William H. Morihouse, Thomaston, Conn. 1. These tubes can be used only as amplifiers. They cannot be used as detectors. 2. Yes, you can do this. 3 and 4. We advise the regular honey- comb coil unless you desire to wind your own. The fact that all honeycomb coils are wound latticewise is to save space, as fifty turns on a tube would take up more space and have more distributed capacity than if it were wound latticewise. * * * 1. Kindly tell me nhat is the best type of receiving set to enable me to hear con- ' certs up to 1,500 miles. 2. I wish to use an inside antenna. Is it as efficient as one on the outside t 3. What would the probable cost be, and where could it be purchasedf 4. Name a good book for the beginner in radio. — Thomas Ross, 34 Brook Street, Sanfard, Me. 1. We advise a receiver incorporating both radio frequency, a detector and one or two stages of audio frequency. There are numerous sets of this type on the market, and as it is against the ethics of Radio World to discuss competitive types of ap- paratus now being sold in the open market, we advise you to allow someone who has handled this apparatus on the outside to give his opinion. 2. The outside antenna is granted to be most efficient, so far as received signal strength is concerned, but the loop antenna has also the advantage of being less trouble as far as static is concerned. For really long distance reception we advise you to try the outside antenna. 3. We cannot quote prices through this columh. See advertisements. 4. See inside front cover of February 3 issue of Radio World for both reference books and experimenters' handbooks. * • • / am using a two-variometer regenerative set, but would like to know if there is a set that will give me better results. I have heard PWX several times.— Fred Johnson, Keystone, Neb. You seem to be getting good results from your set. If you wish to change, we advise you to try two steps of radio frequency, either crystal or tube detector, and one or two steps of audio frequency. A hookup for such a set was described in Radio World, dated December 9. * * » Kindly publish the wiring diagram of the set illustrated on pages 4 and 5 of Radio World dated January 20.— H. B. Clough, 9 Exeter street, Portland, Me. If you will refer to page 6 of the same issue you will find the diagram at the bot- tom of column 2. The B battery is con- nected wrong in the diagram. The plus (+) should go to the plate, not to the fila- ment as shown. * * * 1. Would vernier condenser (43 plate) in the antenna circuit be of any advantage in the set described by Ortherus Gordon in Radio World dated January 20, or would a regular 43 plate condenser sufficet 2. Is the B battery connected right in this hookup? I notice that the plus goes to the filament. 3. Would a potentiometer be of any use in this circuit, and if so, how is it con- {Continued on next page) Digitized by Google

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RADIO WORLD 1! 500 Miles without Aerial By R. M. Pace F!» l-Hooku, of iMin, Wknr, wttfe which Mr. Pan ku < I AM sending you herewith a wiring diagram of my receiving set and I hope that you will be able to use it, as I have found it to be one of the best re- ceivers that I have ever used. Here are a few ideas as to the building of the set The entire set is conveniently and neatly mounted on a panel 12 by 14 inches in the following manner: The panel is divided in two parts by the insertion of a base for the mounting of the tubes, transformers, etc., 7 inches from the bot- tom of the panel. The base for the in- ductances is mounted on the bottom of the panel. On the lower half of the panel is mounted: the inductance, the switches, and the condenser; in the lower left- hand corner the ground binding post, and on the right-hand side the B battery connections. On the upper half of the panel is mounted: The Bradleystat, two rheostats, and in the upper left-hand cor- ner a binding post for the antenna con- nection, while the A battery connections are in the lower right-hand corner, and the phone jack in the upper right-hand corner. As to the material used I will specify the following: A Bradleystat on the detector is necessary, and two model A Rhamstine transformers are suggested. A heavy condenser is also very neces- sary and a vernier attachment will help out very much. With my set, I have logged over 62 radiophone stations, the longest distances being: KHJ, of Los Angeles on the west; WMAT at Duluth on the north; WJZ at Newark on the east and PWX at Havana on the sooth. Without the use of an outside aerial, and using no aerial, at all I have logged KDKA and ten other stations, all over 500 miles dis- tant. I have abandoned the outside aerial (Continued from preceding page) necledf—E. W. Johnson, 1441 Wilton street. Denver, Colorado. 1. You could use a vernier in this circuit very nicely. It would give you much finer tuning, although it is not absolutely neces- sary. 2. The B battery is connected incorrectly. The plus as you state should go to the plate, and not the filament. The way in which it is connected will not work. 3. A potentiometer is of little value in this circuit, as you have only 22J4 volts on the plate; and the advantage, if any, would be so slight that it would not be of any value to bother with it. now, having moved to a location where I couldn't get one up, but am getting excellent results from the lighting circuit by plugging in at the lamp socket. My connection to the light socket is by inductance only, as I am using a length of the ordinary lamp cord (twisted paw). One wire is connected to the inside con- nection of the light socket, the other end of this same wire is taped securely to prevent a contact with the set The other wire connects to the antenna connection. The free end of this wire is taped so that no connection can accidentally be made. I find that with this arrangement that my set if almost noiseless and that sta- tions that heretofore came in weak now come in loud and clear. This arrange- ment is not recommended unless the light wires are all overhead. The current is always turned "on" when tuning in. An- other important feature is the shielding of the set. This I have done with a fine mesh copper wire screen cloth, and I find that practically all body capacity is eliminated. Care must be taken that none B+se/or Tvtes e*f Tickler brounJ - |Q Base feriMtrtWM He FW. S-Phm of pw. of the parts touch the screen, and that it is well grounded, and preferably to a separate ground, although this is not nec- essary. I also wish to say here that my set is at present located under a tin roof, and with this roof being used as an aerial I have got good results, but not as good as with the light wire. If there is any further information de- sired in connection with the building of this set I will gladly give it The cost is small, and I urge any one contem- plating the building of a receiver to give this one a trial. Latest broadcasting map, 15c That is, a complete broadcasting map appeared in RADIO WORLD, No. 8, dated Mar 2a Mailed oa receipt of 15c Radio World Company, 1493 Broadway, New York Qty. MAGNAVOX is "news" THE constant allusions to Magnavox Radio equip- ment in the public press, and the numerous illustrations of Magnavox Reproducer in oper- ation, show how profoundly the radio world has been influ- enced by the Magnavox elec- tro-dynamic principle of sound amplification. R-2 Magnavox Radio with is- inch horn THIS instru- ment is in- tended for those who wish the ut- most in ampli- fying power : for large audi- ences, dance halls, etc., but requires only .6 of an am- pere for the 6eld. Radio SAME in principle and construc- tion throughout as Type R-2. Is ideal for use in homes, offices, amateur stations, etc. Requires one ampere field cur- rent from your filament battery. Magnavox Power Amplifier— Model C CAN be used with any "B" Bat- tery voltage which the power tube may require for best ampli- fication. AC-2-C. 2-Stage and AC-i-C, 3-Stage The facilities and experience back of each piece of equipment bearing the Magnavox trade mark are unrivalled anywhere in the world. MtifTuitox product! imi he hod of good dcoleri firrru/urt. Writ, to ... for illuMrucd booklet The Magnavox Company Oafclaad. CaMbratl New York Otfue 370 Seventh Ave. Digitized by Google

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20 RADIO WORLD f Latest from the DX Nite Owls Page Mr. Smith Again Fran F. B. Mean or .Coraopolls, Pa. KINDLY page Mr. Kenneth Smith. I am using a double slide tuning coil, six inches long and four in diameter, home-made, a crystal detector and con- denser.. Dictagraph phones, are. used. My aerial is V-shaped, about. 5B> feet high and 15& feet lone. Here's my record, not including the nearby stations* WUL, WDAP, WOC, whaz, wh&s, war, wnasr, wlw, WJZ, WGY", WOE As- yoo wfll notice, these are stations listed in Charlotte N. C; Chicago, I1L; Davenport, Iowa; Min- neapolis, Minn., besides ftthwrta, Georgia, and closer onesi. When- yon look you will see I live only 15 miles from Pitts- burgh, and I think you will agree with me that this is some crystal record. I also heard a station in Omaha, Neb., but missed the call letters. Will be glad to hear from anyone interested in my record. Hears PWX Regularly From Frank Edal, Du Quoin, Illinois. I AM enclosing both my records for DX crystal detector and also V. T. detector work. Following is my list of stations heard using a crystal detector without amplification of any sort : KSD, St. Louis "Post-Dispatch," St. Louis, both night and day. Other stations heard at night only are: WCK, WHB, WDAF, WOC, WBAP, WGM, WSB, WDAJ, WGY, WDAP, WWJ, WCX, WLW and WOH. I do not consider it anything out of the ordi- nary to receive distant stations with a crystal set if time and care are taken in construction of the set. I can duplicate a good many of the stations any night that the conditions permit. I do not refer to static and other natural conditions, but to interference frpm the local arc sys- tem which ait times causes trouble to such a degree that it is impossible to hear any- thing at all. My V. T. reception record I consider fairly good. I made this rec- ord using a home-made single circuit re- generative receiver without amplification. I can receive nearly all of these stations every night: KSD, KHJ, KDKA, KFAF, KLZ, KOP, KZN, KYW, KFDF, KOB, PWX, NOF, CKCK, CFCA, CFCN, CJCG, WEW, WCK, WMAY, WIAR, WOH, WLK, WSB, WGM, WGY, WOR, WJZ, WHAS, WWJ, WOAI, WCX, WBAP, WEAK, WDAJ, WDAF, WOS, WOC, WMAB, WJD, WDAL, WHB, WLW, WBT, WOAL. WLAG, WFAA, WEAY, WPA, WDAP, WMAQ, WOQ, WOI, WMAU, WNAL, WAAV, WTAW, WJAX, WQAA, WMAT, WKN, WEAF, WMAK, WNAD, WNAV, WBL, WLAQ, WEAO, WHK, WFAV, WAAP, WOAG, WIAU, NAS, WSY, WJAP, WCAV. WGF, WPAC, WJAN, WKY, WMAH, WIAO, WCAE, WGR, WJAD, WLAJ, WAAW, WMAF, WMH, WAAB, WHAM, WLAL, WAAC, WEAB, WPAL, WMAJ, WMAV, WKAL, WOAA, WBZ, WDAE, WOAN, WWAC, WWI, WAAH, WCAY, WGAS, WNAS, WDAO, WNAC, WAAF, WQAQ, WOAC, WAAL, WOO, WBAV, WCAS, WHAZ, WIAB, WRAM, 2XB, 501, 5RH, 5WA, 5XY, 5ZA, 5UU, 5XAY, 8X1, 8XJ„ 9XU, 9XD, 9BWI, 9XAQ, 9DTF and 9YAF. My hours of listening in are from about 5 P. M. to 1 or 2 ATM. While this list of stations looks big, it is nothing very great as it has nearly been duplicated by three other people in DuQuoin using a hook-up similar to mine. I receive PWX and KHJ, my two best DX's, regularly; THE Editor of RADIO WORLD will be phased to receive sketches of hook-ups drawn carefully in black ink or heavy pencil from the "DX Nite Owls" who send in records with a view to publishing them. Send hook-ups of your sets, presided thajr contain somethlna unusual Send; of the various n isles of Make your letters brief and informative. Write on one side of the paper only. RADIO WORLD. PWX on Wednesday and Saturday, and KHJ nearly every night. Any one desir- ing hook-ups of either set may have them by writing to me for them. I also invite investigation of either set and also the record. 1 am using a pair of Federal 2200 ohm headsets, a 21 plate variable condenser, bought "knocked down" and assembled myself, a variocoupler with taps taken oil every 10 turns up to 90 turns. My rheostat is a Howard Vernier and my tube a Cunningham detector. The hook-up while simple and very easy to understand, is very effective. Further information concerning set may be had by writing to me. Code from Colon, Panama From Burdens Bowman, CI I S. McClure St, Marion, Indiana, J SAW in Radio Worij) for January 13 that you were interested in unusual hook-ups. Using a variometer, two home- made honeycomb coils, a 23- plate con- denser and phone and grid condenser and the W-D 11, I have heard KYJ, Los Angeles Examiner, a distance of 2,223 miles ; KDY Y, Denver, a distance of about 1,600 miles. I receive music from Schenectady, Kansas City, Chicago, Toronto, New York City, Atlanta, New Orleans — at a distance of 300 to 700 miles— every night. Any night Fort Worth is sending I can get it or any other station within a thou- sand miles. On January 11 I received music and lectures from WWJ, WLK, WJAF, WOH, WOR, KDKA, a station at Albany, WGY, WMAV, WHB, WOC, WBC, WEAF, WFAA, KYW, WDAP, and WGY's late program. If any of the readers are interested in the way I have my set hooked up I will gladly forward information. DX New York to Los Angeles From Howard A. China, Member of Hudson Radio Club, Inc., and Radio 2CEG, ZU West ltzd Street, New York City. BESIDES listening to amateur DX I sometimes listen in to broadcast DX. I have heard practically all the stations within a 1,500-mile radius, which many others have reported, so I won't bother to enumerate them. The best broadcast DX that I have done is KHJ, Los Angeles. I heard them several times during the early part of January. Have received a letter of acknowledgment from them. This was done on a single tube and with ordinary regeneration; no amplification or super- regeneration. I think this is a record, as I haven't seen its equal in print as yet. Considering the fact that I live in the heart of New York City, surrounded by high apartment houses, I think this isn't bad for one tube. I maintain that if you can't hear it on detector, audio-frequency amplification won't help because you can't amplify what you don't detect. From Iowa State University From Harold E. Pratt, Member of WSB Radiowls, SM S. Capitol St, Iowa City, Iowa. AM a student here at the State Uni- versity of Iowa and during my spare time I built a detector and one-stage re- generative set I might add that owing to the conditions here I was unable to put up an outside wire, but am using my light fixture (and without any plug). Just wrapped a piece of lamp cord around the center of the three light fixture in my room, and got the following: WOC, Dav- enport; KSD, St. Louis; WHAS, Louis- ville; WWJ, Detroit; WDAP, Drake Ho- tel, Chicago; WGY, Schenectady; 2X1, Schenectady; KYW, Chicago; WBAP, Fort Worth; WHB, Sweeney Auto School; KSAS, Denver; DN4, Denver; KLZ, Denver; WGM, Atlanta Constitu- tion; WSB, Atlanta journal; KHJ, Los Angeles Times; WLAG, Minneapolis; WFAA, Dallas; WDAF, Kansas City WEAE, Fort Dodge; WJZ, Newark; WNAV, Knoxville; WLW, Cincinnati; WDAJ', College Park, Georgia; WOL Ames, Iowa; KDKA, Pittsburgh; KDYS, Great Falls; WGF, Des Moines; WFAT, Sioux Falls; CFAC, Calgary, Canada; also stations at Okmulgee, Okla., and Birmingham, Ala. I Heard Ship Alaskan From E, G. Barnes, Mt. Vernon, Ohio. AM not a DX Nite-Owl, but I have had my feet wet, as H. J. Hall says. I have a home-made set consisting of 3 pancake coils, 1 tube, 1 grid con. and leap, 1 phone condenser socket and 2 home- made variable condensers, no aerial. The ground is wrapped around a water pipe in the cellar; not one drop of solder in the outfit. My tube is U. V. 200. This set was set up November 26, not 60 days ago; but I have had musical numbers from 81 different stations and 5 ships. Twenty-seven states are on my list One Sunday evening I had Drake s Hotel at Chicago for two hours clearly, without touching a knob or dial. On January 15 from 4 P. M. to 10:30 P. M. I had 27 stations of which 12 were new ones, every one clear and loud. My farthest points were Boston, Hartford, Quebec, Portland, Oregon; Los Angeles, Austin, New Or- leans, West Palm Beach and back to New York City, and 72 others. Also had WKG on ship Alaskan. I should be glad to know the route of this ship. Boys, have I had my feet wet? If not, get in. Do you take the Radio World. If not, get it. It's good. Will be glad to hear from any of you. This hook-up will be furnished on application. In Less Than Three Months From Cyril Cornwall, Osage, Iowa. ON Friday night, January 19, I heard the following stations : KDKA, WGM, WDAP, WPA, WCX, WEAF, KYW, CJCG, WOC, WAAP, WWJ, KSD, WDAF, WCAZ, WFAA, WMC, KHJ, WOAN, KLZ, WOS, CKCK, WAAH KFAF, CFCA, KFBB, WGY, WLW WBAP, KDZQ, WSB, WDAJ, CFCN and KNJ. I listened in from 7:30 p. m. to 1 :00 a. m. Besides these broadcast stations 143 amateur telegraph stations were copied, making a total of 176 stations in Sj4 hours. With my receiver I have heard 132 stations in the United States, one in Havana, and 7 in Canada— a total of 140— all since November 5, 1922. {Continued on page 31) Digitized by Google

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RADIO WORLD ' 21 RADIO SUPPLIES ALWAYS AT SENSIBLE PRICES AU Were CMftar. til -3 It Mean, wttk Free HMk-Ui |4.|| IV, V.H Takes 4.M I VeM Debater Takn t.M i S8 .r^.^..::::::::::::::::: Mi WHITE'S (IwrnertJ- Stasias' Badle Bapptf Oo.) 1SS KA8T SSKD ST., MBW TOU CITY Coefc with Order. Allow Pot tag*. King Sr. Virionetn 1M to W* Hi MiHn hardirare Bawl redactae •»- parity 1 hflli Build. 8 to* «K"s«M~sr' OitorasfcMd 6y manit/aodirw direct to utmr. Ask Inlv to «K vw aw to yea, Aram Mfg. C»., 38 East 23k. St, N.T.C. The Niftiest Short Wave Timer on the Market Only tS.N A PP on 1 lb. Sand far pamphlet. L. W. GOODMAN DREXEL HILL, PA. D arise • . Nerrlsnwa. Pa., aria*: Ustsalai rsssatfy with ay aoODMAN. burs' a rslsa, "ws ara eew II Bliss tat tnm laa Fraaaiase." Tina DENVER an la sad auk tat skis. Bel^anto LOUD SPEAKER It follows the natural function! of the human throat. The receiver is the vocnl cord (A); the long tapering inner horn it the throat (B); and the "sounding. hmr-l" at the top is the roof of the mouth (C). A guarantee of superb tone. Ia adjusted for regenerative two stages of amplification, also five tube radio and audio frequency. Special phone, cord and plug, price 130.00 F. O. B. New York. If dealer can't supply, we can. Foil line of radio parts. At «aur dsalar sr elrest Iran auk*. Bel-Canto Corporation 417 Eaal 34th Street, New York City RADIO WORLD . ■TAUT «TM ■TOT WMPH—DAT (Burnt kattjbpat ar ua in* noADWAT. raw ion. it t. TECHNICAL ED1TOK u SUBSOUPTION llll.M. at laa Past OtBaa at Ms* Tar*, taa aat at Hank S, 1|TI. M. It 11. Maw Tsre. ansae IMPORTANT NOTICE While essrr pasatMa am la Radio and the Churches Not only docs radio bring the church into the home, but it brings church serv- ices into other churches, says "The Radio Dealer." The story is told of a church out West that lost its pastor. No substitute clergy- man was available and it looked as if there would be no services on the Sab- bath. A radio enthusiast saved the day. He rigged up a receiving set with a loud speaker. When the congregation assem- bled on Sunday morning it was surprised to see a mechanical device on the rostrum instead of a clergyman. Soon the contraption on the rostrum prayed, sang, talked and preached. The sermon was said to be a Rood one. It was probably better than the congrega- tion was in the habit of hearing, for it was a poor church and had little money. No one knows what unexpected influ- ences may be exerted by radio on church affairs. It may make possible the elimi- nation of a certain number of clcrgvmen. It may develop a new chss — ecclesiasti- cal orators — who will specialize in broad- casting and wiil leave the pastoral *ork to be done bv others. A recent survey shows that the broar! casting in this country of Sunday church and rclieious services covers 65.2 the area of the United States — surely enough ior most people. Some large churches are now broad- casting their own services to those who stay at home. Others will doubtless do this soon. Churches that aim to serve as "community centers" have receiving sets for the benefit of the church clubs and organizations seeking sociability and pleasure in the church-house. 4 Let Radio Radiate Your Home H"> _ Our Prtea 1*00 Elwaun rhora . IS.U ti ll Wnttrn EWtr.r Prunes •lira asr caps am] muf- flers 7.81 J5 0« F«l«r»l Jr CrrsUI H*t. . .11.11 6.00 riftb«f Vtrloaelars sod Couplera 1.7s 1.30 Klcanar V*mt«r ahso- _aute is 3 50 Wortrila llaktHW 111 DaSNsj Caupssr 3 30 1 00 ]'.:,.„ B.kiJlu. Serial. . l.TJ Brutbl BUr "B" It.- Urles I 11 l.ll.rsdml Pbaasa lis 11.11 Cutttn, ^Wuhln.1^ ••" Write for free cataioeue Psrfsruao Pars Parosl INm Perfection Radio Corp ii» wnr tsRo htuxt. jam ton RADIO At Cut Prices Just a Partial List of the Many Bargains Offered $5 .50 Murdock Double bead set* SX« 15 00 Acme Transformer, Radio and Audio *.« »1«. 50 "Homcharger" De Luxe IMS V5 .50— 180 Variocoupler on bale elite silk wound wire US $15.00 Western Electric Phones 7.4S JrVOO Genuine "Tuska" molded variom- eter with dial 1*4 Ammeter for Testing MB" Batteries.. Hv«Ur ff •tittmtt «> th J*r. MOOCLLaV— Tae U-.4t,.t RaeKe Mail Hiuvc. 1923 Will Not Be Complete! Wlthoat • Tear's Sabacriptloa to RADIO WORLD (52 nun here) $6.00 aal 91 a year extra tar > fa UN Broadway If ew Terk, If. T. Digitized by

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22 RADIO WORLD Advertising Rates, Display, $5.00 per inch, $15000 per page Radio Merchandising Classified Quick-Action AdrertUtnf , 5 cents per word TtUphont Bryant 4796 Orders by Radio Goods Advertised in Radio World Jean Bonner, of 6009-A Horton Place, St. Louis, Mo, recently saw in RADIO WORLD an advertisement of the Sunbeam Electric Com- pany, New York City. Mr. Bonner sent a message by radio to a friend in New York City ordering' him to purchase radio apparatus for him, as per advertisement in RADIO WORLD, and to have it sent to him P.P. collect. The order was filled and sent immediately. This illustrates how radio can be used efficiently and expeditiously in ordering goods. If Mr. Bonner had written the order, it would have taken it three days to reach New York, and then it would have had to go through the usual mail order routine. Who will establish himself as the first Radio Buyer for the trade and for fans? And how's this as a testimonial for RADIO WORLD as an advertising medium of quick results, White Cement for Amateurs Who Make Their Own Coils A cement recently put on the market by the White Radio Co., of 123 East 23rd street. New York City, will probably meet with widespread acclaim by radio ama- teurs who construct their own coils. It is a col- orless liquid, which is put on the wound coils much the same as shel- lac but does not have the drawback of shellac; namely, it does not create distributed capacity, as does shellac. By means ol this liquid self-supporting coils can be made. It is only necessary to wind the coils on a core, over either paper or a layer of string, then coat the coil with the liquid, allow it to dry and, after another coat, remove the string; or paper, and the coil will be found to be self- supporting. It is a chemical composition, em- bodying ether much the same as collodion, and therefore, when dry, has a whitish appearance, but by the addition of another chemical, it forma a very hard base which is not flexible, as is collodion. No More "B" Battery Trouble A new battery manufactured by SUbenai Radio Co., 1M3 J aroma Ave,, Bronx, N. Y. C A small "B" battery manufactured by these people has recently been put to rigorous tests, and found to be ideal for every purpose in a re- ceiving circuit. The battery consists of a small molded rubber case with 10 divisions. Each divison holds a postive and negative plate such as is found on the larger batteries used to light the filament. The construction is such that the entire cover can be removed and the elements exposed for inspection. The battery is charged on a C current through a simple rectifier con- sisting of a atrip of aluminum and lead in a solution of borax, with a 60- watt lamp in series. A load was put on this battery equivalent to 300 hours' service, and very little depreciation was noticed at the end of that time, outside of water needed due to evaporation. It is of rigid con- struction and will outlast many of the dry cell type. How Radio Helped an Employer to Hold His Employees IN this busy world, there is always a demand for something that will re- lieve the monotony of the daily grind. This was proved by one of the largest manufacturers of knit goods during the past few weeks, in an ex- periment, which was as follows : This manufacturer had allowed the girls to have five minutes out of every hour for recreation or rest, arguing that they could work better and pay more attention after a few minutes' rest. Having a small son at home who was interested in radio, he tried the experiment of installing a small set in the girls' rest room in lieu of a phonograph. He noticed that a very great interest was taken in the concerts and goings on over the radio, and therefore thought that the girls might overstay their rest periods and shirk. But by careful observation, he found the opposite to be the case. Being interested in the new-found diversion, they worked hard, to pass the time, and did not waste time as was usual, by lagging, but hurried back to work to discuss the different things they had heard during their five """as" result, the girls, instead of growing dissatisfied and leaving, stayed and seemed happy, and the news spread far and wide that none of the girls in his employ were leaving, and he could get any number of girls if he wanted them. New Radio Firms (The firms and corporations mentioned m these columns can be reached by communi- cating with the attorneys, whose addresses are given whenever possible.) Brotherhood of Electric Workers, Local No. 3, Manhattan, realty, $5,000; R. L. CHara, C Dubourg, G. W. Whitford. (Attorneys, McCau & O'Leary, 51 Chambers St.) New Bath Co., Brooklyn, electric. $25,090; E. A Levin, B. O. Jackson, J. L. Fitan. (Attorney. A. A. Levin, 215 Montague St.. Brooklyn.) Radio Clearing House, Manhattan, %2Ofi0O; W. Scadron, B. E. Simmons, J. E. Onorata. (Attor- ney, L. Scadron, 149 Broadway.) Da barton Corp., Manhattan, electrical supplies, $50,000; W. homashower, S. Snyder. (Attorney, A. A. Arafan. 140 Nassau St) A. Maclntyre Electric Co.. Albany, $7,500; A. and E. Maclntrre, J. S. Sanford. (Attorney, H. W. Williams, Albany.) _ _ Artglo Electric Corp-, Manhattan, $15,000; J. R Lundy, W. C. Lena. T. F. Lee. (Attorney, J. Schultz, 1 Madison Av.) RADIO STOCKS (Quotations as of January 31, 1923, furnished by Frank T. Stanton & Co, 35 Broad Street, New York City, Wire- less Stock Specialists.) Stock Bid Asked American Marconi Unstamped $5 $7 American Marconi Stamped.. 5c 20c American Tel. & Tel 121 % 122H Canadian Marconi 2% 3 De Forest Radio 7 10 Dubelier Condenser 6 6# English Marconi com 11 14 English Marconi pfd 11 14 Federal Tel. Co. Calif 6J4 7% General Electric 182 183 Mackay Co. com 103 107 Manhattan Elec. Supply 53 54 Marconi Int. Marine 8 10 Radio Corp. com 3f$ V/t Radio Corp. pfd. 3 1% Spanish Marconi 1 3 Western Union 112 113 Westinghouse E. & M 62K List of Stations Free A neat, attractive and handy booklet showing a complete list of broadcasting stations has been prepared by Modell's distribution through the radio depart- ments of their New York stores. Read- ers of Radio Worud will receive the com- plete list free, if they will send their name and address together with a two-cent stamp to cover postage, to Modell's, 58 Church Street, New York. A Regular Job ! The Director of Radio, or whatever his title may be, will have his hands full controlling the waves, it is pointed out by one fiend on history, who recalls that Old King Canute got into difficulties some years ago and wet his feet terribly try- ing to do the same thing. BEND MB YOUR PHONES for repairs. All makes. Satisfaction sruarantaod. Reasonable charges. «oy. ltl West 4—1 WL. Hew Tsrfc Otty Digitized by Google

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RADIO WORLD 2. Big Hotel Uses Radio In Important Way The following telegram to Radio World explains itself : 14NYWA840AM 87 NL MC CHICAGO ILLS JAN 31 1923 RADIO WORLD 1493 BWAY NY WIRELESS TELEPHONIC COM- MUNICATION BY AN INLAND STATION ON A PREARRANGED SCHEDULE IS BEING CON- DUCTED BY US FOR THE FIRST TIME WITH AN OCEAN LINER THE BERENGARIA SAILED JANUARY THIRTIETH FOR FRANCE PASSENGER MISS FLORENCE MCDONALD OF SYRACUSE NEW YORK THROUGH COURTESY OF THE CUNARD COMPANY HAS IN HER CABIN A ZENITH RADIO RECEIVING SET AND THIS MORNING WIRELESSED BACK REPEATING OUR MESSAGE TO HER PROVING RECEPTION WE ARE SENDING EACH MORNING THIS WEEK AT ONE AM TO THE BERENGARIA WE WEL- COME OBSERVERS IF YOU CARE TO SEND ONE DRAKE HOTEL BROAD CASTING STATION Latest Radio Broadcasting Stations (Latest official addition* to the Lilt of Radio Station* ol the Unitad States.) Station* broadcasting market or tceather report t (485 meters) and mutio, concert e, lectures, etc. (360 and 400 meters), alphabetically by cat: lettert. Call signal! Station operated and controlled by- Location of *tat ion. KFAZ KFCM KFDH KFDJ KFDL KFEP KFHJ WOAS WOAT WOAU WOAX WOAY WPAH WPAT VVPAK WPAP WPAO WPAR WPAS WPAT WPAU WPAV C. H. Weatherill Redley, Calif.. U48 Z Street Richmond Radio Shop Richmond. Calif University of Arizona Tucson, Arix Oregon Agricultural College Corvalli*. Oreg Knight-Campbell Mutic Co Denver, Colo Radio Equipment Co Denver, Colo Fallon Co Santa Barbara, Calif Bailey'* Radio Shop .. Middlctown, Conn Boyd M. Hamp Wilmington. Del., 215 Market Street... Sowder Boiling Piano Co > Evansville Ind 380 Franklyn J. Wolff (Monument Pottery Co.)... Trenton, N. J Mj> Wave length*. . MO 360 MO mo MO MO MO MO MO Ala., 3017 Fir*t Avenue John M. Wilder Birmingham, South. Wi*con*in Department of Market* Waupaca. Wi* Doolittle Radio Corp New Haven. Conn. .......... .... North Dakota Agricultural College Agricultural College, North Dakota.... Theodore D. Phillip* Winchester. Ky General Sale* & Engineering Co Frostburg, Md R. A. Ward Beloit, kan* J. & M. Electric Co Amsterdam, N. Y St. Patrick* Cathedral El Paso. Tex Concordia College Moorhead, Minn ...... Paul Tinetti & Son* Laurium, Mich WPAW Radio Installation Co Wilmington, Del WPAX S. W. Radio Co. (J. R Shumate, jr.) Thomasville. Ga Southwest Missouri State Teachers College.... Springfield, Mo E. B. Gish Amarillo, Tex Moore Radio News Station (Edmund B. Moore). Springfield. Vt.. .... Appel-Higley Electric Co Dubuque. Iowa AL Coles County Telephone & Telegraph Co Mattoon, III AY Ga«ton Music tc Furniture Co Hastings. Nebr Black Hawk Electrical Co Waterloo. Iowa Plainview Electric Co Plainview, Tex Wright A Wright (Inc.) Philadelphia, Pa IN WSAT WWAI M0 4*3 M0 360. 48$ M0 M0 M0 MD M0 M0.4RS M0 M0 M0 360 360 360 360 360 360 360 MO 360 Several Senators, Con- gressmen and Governors on WJZ'S Program The radio audiences that have been fa- vored recently by the activities 'of WJZ, the Radio-Corp.-Westinghouse Station, broadcasting direct from the grand ball- rooms of the big New York hotels, thus enabling the invisible audience to hear the addresses of some of the world's fore- most men, has the opportunity of hear- ing during the evening of Feb. 1 ad- dresses of U. S. Senator William II. King of Utah, Congressman James A. Frear of Wisconsin, and Thomas W. Sisson of Mississippi, Bishop Wm. Manning of New York, Governor Al. Smith of New York and ex-Governor Charles S. Whit- man of New York, the latter of whom was the presiding officer at the annual banquet of the New York Society of Mil- itary and Naval Officers of the World War, held in the grand ballroom of the Hotel Plaza. This association is com- posed of several hundred socially promi- nent Army and Navy officers who reside in New York State. Ex-Governor Charles S. Whitman of New York it the president of the association. CoL Herman A. Meti, former Comptroller of New York pty, was chairman of the dinner committee. The long list of vice-presidents include Brigadier Generals Oliver B. Bridgman, James Rabb and George Wingate. The broadcasting of the addresses began at 9 :30 P. M. Coming Events PERMANENT RADIO PAIR FOR BUYERS, Hotel Imperial, New York City. Opem frosa September. 1921, to May, 1*23. SECOND DISTRICT RADIO CONVENTION. Botal Penawylvaaaa. New Tart City, Mart* a, 1 and 1. 1923. FIRST UNIVERSAL EXPOSITION OF IN- VENTIONS AND PATENTS, Graad Central rHI aea. New York City. Fabcmry V m ML Inns— In, IMS- SOUTH JERSEY'S FIRST RADIO- ELEC- TRICAL SHOW. Third Radsaaat Araaory. Caa* len. N. J., February SUM, tachaslv*. D-X- (DISTANCE) The Ambition of Every Fan D-X- RADIO COMPANY specisliie. in Radio instruments designed for DX (Dis- tance) Work. To receive distsnt station* your instrument must be built with proper equipment. And that means the D-A* Radio Company— particularly since we offer highest quality radio parts at lowest prices. SPECIAL GENUINE FISCHER 180° VARIOCOUPLER M TAPS. SEVEN IN UNITS SOLDERED LEADS READY TO USE REGULAR PRICE . $5.00 SPECIAL PRICE $2.25 Remittance must accompany all Order*. Check* or stamps not accepted. Mer. cbamlise shipped post paid east of Mississippi FREE CATALOGUE ON REQUEST D-X-Radio Co. U3 Liberty Straw! New York City REAL RADIO BARGAINS 33 Plate Var. Cond $!.!• 49 Plate Var. Con \M The New Bull Dog Grip VV. O. It Socket M Variable Grid. Leaks.... St Rheostats — Acme .•• Murdoch Crystal Sets Complete with 9000 ohm Phone, Aerial, etc tst Acme 2 Step Amplifier (List 135.00) ITS* M n r d o c k 9000 ohm Phones SS8 9 inch Dials If Paragon, Card well. Acme and all Standard Apparatus on haad at Lx»w»«t phf • '.~1 If • ► - York Digitized by VJVJV^LV.

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24 RADIO WORLD RADIO PANELS Cut exeotly to else ud shipped within II boon. H, loth tblefc. l%t par nun lath, t/ll tosh, 1U« per equere insh. Made of thshtebest grade Mask Aon. Thlt material rxaaasnee blib dielestrte etrenrth. la tanuln, unbreakable. «■ to wars ud takes • nles flnUtt. Speelal off«. IxixH. >0e; «i lllle. S1.S*. WILEY PANEL CO. MM a*. Oeatral Put An. Osttaee. lit. Two Smmm RADIO TOOL SET CtottfacMltT I rtosaTUer I4jM la B*c WW kMrtf Ires KH.Jf.7t Witt AetjeisSb MMt M CEB CO, IN Park PUw, Now York Cety £s25 A DAY ST hd%J Sell j no Shirts tArcs shirt UDiilutanr wuti areata to Mil oomplete Una of ihlrU, ravjamaa andntrbtahu-to dlreot to wearer. Ad rertleed brand --exoloeire patternt-eaty to aelL No experience or capital re quired. Kntlrelr on proposition. FREE 8HELTONB LOUD* SPEAKER With erarr pair at Original Na Baldwla Type 0 At %\iM for trua tout, Caeh with order or C70. D. WALTER SCOTT If ft Lskee Pleat Uaaar MeawJelr. Ha* Jersey Why an to Public Libraries Y. M. C. A's. K. of C's. Y. M. H. A's. Army Posts Social Clubs Industrial Libraries And others in this subscription group ordering subscriptions for Radio World from all parts of tht U. S., Canada and foreign countries? THE REASON Because so many Of their members Are interested in Radio That they want to read RADIO WORLD every seven days Ask the Association or Club To which you belong To subscribe for RADIO WORLD The Great Xttuitrated National Weekly " v Now York City Opera by Wireless Broadcasting opera, which has been done in Chicago for the past two seasons, has at last reached London, says an edi- torial in the New York "Globe." Ex- cerpts from the British National Opera Company's performances at Covent Gar- den have been transmitted with such suc- cess that broadcasting has been adopted as a nightly procedure in London and plans are being made to continue the pro- cedure when the opera company moves to Manchester. In Chicago an arrangement was made between the opera company and the West- inghouse Electric Company by means of which microphones were placed in the Auditorium, and through these the sounds are conveyed over telephone wires to the broadcasting stations. Opera was thus made audible for a thousand miles about the city. Fifty years ago, when Matthew Arnold visited the metropolis of the Mis- sippi Valley, local patriots admitted that their city was short on culture, but they said that when they got around to it Chi- cago would make culture hum A city which distributes grand opera through the air to points as far distant as Denver and New York can be fairly said to have made good the boast. According to reports from the west, the broadcasting experiment has been profit- able to the opera company as well as to the sellers of electrical devices. The wire- less has stimulated an interest in opera and increased the patronage of the Chi- cago company. This is a natural develop- ment and a wholesome one. It is, of course, impossible to overestimate the im- portance of an undertaking of this kind, since the great problem of the modern world is to distribute justly the amenities of life, and among these the opportunity to hear good music is not the least. The comfort and the pleasure which the trans- mission of grand opera from Chicago must give to the music-loving inhabitants of villages and farms remote from any great centre are very great. Life for uncounted thousands is thereby enriched. According to the "Manchester Guard- ian," the social effects of the British exper- iment have been highly interesting. The London correspondent of the paper de- scribed the excitement of his charwoman, whose family had spent an hour and a half listening to a Mozart programme through a receiving set made by her son, an engineer's apprentice. The episode could undoubtedly be multiplied many times by the testimony of Americans to whom new opportunities had been opened by the radio. It would be exceedingly interesting to have the Metropolitan Opera Company broadcast its programmes. Although the profit in such a venture would not be immediate and direct, distributing music through the air would probably be like bread upon the waters, and indirectly here, as in Chicago, the paid attendance would be increased. Is not the experi- ment worth while? It Can't Be Done! Some Congressmen seem to think that radio can be laid out like pastures or grazing lands with neat wire fences which would keep the broadcasts and messages within the confines of a state. Two of them actually believe that Stole rights are envolved in the bill before the House and want local radio control left with the state governments. "DX's," take notice! * » » Fully Descriptive „"I call my new maid 'The Wireless Wonder.' " "Why?" "Because she's always 'listening-in* I"— London Mail. RADIO PANELS HI ih dlelertrla 9"mM" 8"xJ4" lt"xt«" Maaafattarere- tatslal aim aollerasd. A at >ti wasted. PAGESON COMPANY Ban «S, Manhaata Statlaa. St Leala. Ma. fl-SS US LTS WE ARE MANUFACTURERS OF FINE RADIO FURNITURE— CABINETS, TABLES AND ROLL TOP DESKS. Hardwood, hand-rubbed, mahogany and golden oak finish. Poetags and Express paid by ua. It will pay you to •and for uiluaa and description. THE SOUTHERN TOY COMPANY Radio Diviaion Hickory, N. C RADIPHONO ADAPTER $2.00 Hera la an afflalaat em VletroU. Vale _ of molded oansporJUen. B eliminates meullle torted aouz to be satisfactory or money refunded If your dealer eannot eupply you tend as II et and one by parcel p— we wlU mall i 671 Phone, Market I ) Novck B" B. tj NOTE THE INSULATED BINDING POSTS AN D^7l K^WIR E CONNFCTOR CO. EARBORN ST. M 1 c AGO N O V O ,-424 W.MSJ - NEW YORK RADIO BROADCASTING MAP FOB the benefit at those Interested la Bad** and these who are becoming Interested. Basal MsNalhr * Oanrpany bare prepared a paMl- eatloa containing a wealth at liifiamillaa et iraataat raise. It show* la the meat n seal i tern aire way, the lata t1 en of the broadcasting rtitlaaa flT.i their dacxlftcetloa, the sail letters, ware lengths. ownership, eta, et each. and enjoyment __ ___ MeNally Sadie Map of United 1 Plata, saturate and ap-to-data. It Is «"»" an In the marslne. Cantaalant poskst Price 85e Each THE COLUMBIA PRINT Vn BROADWAY NEW YORK CITY Digitized by BROADWAY NEW oyGuU^

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RADIO WORLD 25 ARE YOU INTERESTED in FOOTLIGHT NEWS AND GOSSIP? Pictures and intimate gossip of some of the entertainers you hear via radio. If you want to keep posted on everything connected with the American stage read NEW YORK STAR $4.00 a year (52 Uauae) $2.00 Six months $1.50 Three months 10 cents a copy Trial Sub. Offer NEW YORK STAR 14*3 Broadway, N. Y. C Send New York Star to my address trial sub. for three months (thirteen issues) for the accompanying $1.00. Name Street No. City and State As Binns Tells It During the two weeks' period of the third annual amateur trans-Atlantic wire- less telegraph tests amateur operators in England, France and Switzerland suc- ceeded in receiving signals from 31b American amateur stations, says Jack Binns in the New York "Tribune." For the first time European amateurs trans- mitted to this country, and two stations in England and one in France were heard by a tew amateurs on this side. While the tests were completely suc- cessful far beyond expectations, they clearly show that the American amateur is far ahead of his European colleague in handling transmitting apparatus, but the latter exceeds the American in operation of receiving equipment. As a result of the success the American Radio Relay League of Hartiord, Conn., under whose auspices the tests were held, announces that a new scries of tests will be shortly undertaken. These will con- sist of using certain chosen stations on both sides of the Atlantic to transmit complete messages across the Atlantic both ways. This is the most ambitious undertaking yet attempted. Hiram Percy Maxim, president of the American Relay League, says : "The news that has been received dur- ing the last two or three days is only a fraction of what really is the case, be- cause when the mail has had tune to come in from remote places we shall tind that people in Iceland. Alaska, Africa, South America, Australia and some of the re- mote little islands in the South Pacific have been in on this thing also. We know that they are listening, because we know of them and their work, and it is a certainty that several of them must havo connected up in these recent tests. Porto Rico and the Hawaiian Islands are al- ready among our intimates, tor we com- municate nightly. One of us, George E. Cannon, of New Rochelle, N. Y., has ac- tually had his spoken word reported in both England and France, and it must be borne in mind that Mr. Cannon's radio- telephone is purely an amateur one, lo- cated in his home residence in New Ro- chelle. "Another very important think about these tests which is tremendously im- pressive to any thinking person is the fact that this whole business has been worked up and actually accomplished by young American amateurs, with abso- lutely no help from any outside their own number. Not only have they invented, constructed and operated transoceanic short-wave radio communication, but they have secured the liberation of their fellow amateurs in several of the European countries by the force of their energy and their example. The laws of Canada. Great Britain, France and Switzerland have actually been changed by the influ- ence brought to bear by these vigorous young Americans." Newsdealers Attention You should keep a food supply of back ambers ol RADIO WORLD oa hud all tb« lima. It has beta the eapeneaee of bub? dealers that a purchaeer of RADIO WORLD lor the &r*1 time will almost immediately want tbe back titimberi. some of which arc already oat of Print and some of which are difficult to f«. THI PUBLISHER WILL FTRNISH BACK NT. MBERS TO DEALERS DIRECT OR THROUGH TOK AMERICAN NEWS CO. AND ITS BRANCHES. Dealers ehould hold their onioH copies for a reasonable lenirth of time RADIO WORLD of October 2t contained a full peye of contents of back numbers to th»t dete 15 cents per ropy; •ny sreen numbers fnr »1 00 RADIO WORLD. 1491 Rroadwar. New York. PATENTS Emptty rroniled. Trade rta sasieiarad la tbe D. 8. sad abroad. ('* U or write FREE ADVICE. .nisei. VuderbUt Till. MANUFACTURERS PATENT CO.wcl •00ir™i S20 FIFTH AVE NEW YORK GITHENS TRUTONE RADIO HORN— LOUD SPEAKER on* to sell hum Include* Load Speaker Trutoee bas beaa ptwaaaaaed tbe baa m tb» amrtM by areata, ll has a ear. trae un* Steer ~a. fan aSmjld try Trutene end eeeapare It attb etbara a TOO dea't and Trutene lbs baa. roar SMoer will be rrfunded. II U setd oa s lea der trial weeey-bea* ■uaraatee. If eat earned by ran- dealer write as. Distributors and Dealers. write/ AUTO PARTS MFG. CO. ISIS Trembly Are. SURPRISED? WEREPAm VACUUM TUBES HARVARD RADIO LABORATORIRS > M***e I Pare*] rest a*).*. Fifty-two issues for $6.00. Sub. De- partment. Radio World. 1493 Broadway tf. Y C COMPLETE YOUR FILES OF RADIO WORLD FOR 1922 numbers of Radio World are becoenin* scarcer all tbe time. We can now furnish wan with numbers from No. I to date at fifteen cents a copy. Any seven nonabers fur ana dollar. RADIO WORLD. ISO Broadway. New York Qty Digitized by Google"

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26 RADIO WORLD The Radio Primer A Weekly A. B. C. of Radio for the Beginner, in which Elementary Facts and Principles Are Fully and Tersely Explained and all Words and Terms Used by Amateurs and Experts Defined The Beginner's Catechism — By Lynn Brooks TTf HA T is meant by an open circuit as applied to a radio setf yf/ The open circuit is that part comprising the aerial, the tuning inductance, condenser and ground. In all it is the primary circuit, and is termed open because there is no direct line where the current can travel.' An open circuit in line telegraph is generally a break. * * * What is meant by^-the closed circuity— as applied to radio t The closed circuit is that part comprising an inductance generally shunted by a condenser. The frequency at which either of these two circuits oscillate depends on the amount of inductance and capacity in both circuits. In other words, both the open and closed circuits will oscillate when the inductance and capacity of each is alike. * • * What^ is the easiest way of placing a condenser in the primary (open circuit) of a receiving set in such a way that it may be either in series or parallel t By placing a series parallel switch in the circuit which allows the condenser to either be in series with the primary inductance or in parallel. * * * What is the effect of placing the condenser in seriest The effect of placing a condenser in series with the primary coil of a radio circuit is to cut down (decrease) the wave length. » * » What is the effect of placing a condenser in parallel with a coil* When a condenser and an inductance coil, as in the primary circuit of a radio set, are placed in parallel, the effect is the same as if additional wire had been added to the inductance. In other words, it increases the wave length. * * » What is absorption T By absorption we mean that portion of radiated energy that is lost due to atmospheric conductivity, or electric conductivity, of some nearby body, such as a tall steel structure. A tall building in the vicinity of a station materially lessens the radiated power by absorbing some of the eilergy as a sponge absorbs water. « « • What is hysteresis f Hysteresis is the slowness or lagging when a change of condition is taking place in an electromagnetic circuit. In a circuit that embodies iron or steel, it is generally manifested in heat, wheh dis- sipates the active energy. That is the main reason why iron win cannot be used in radio circuits. The small amount of energy is dissipated or used up in production of heat, due to the molecular motion produced in the substance by the electrical energy. In a magnet (electro magnet), if the current is sufficiently strong in the coils, the heat can be noticed if the current is left on long enough. This is the main principle used in heating coils. • * * What is meant by A. C.T This is the abbreviation for alternating current — an alternating current being a current which gradually rises in value from zero to maximum in one direction, and back to zero, and then repeats in the other direction. One alternation is a change in a current from zero to maximum and then back to zero. « • * What is a eyelet A cycle is a complete change in direction, as noted above, or from zero to maximum to zero, then to maximum and back to zero, in the opposite direction. This, as described, is a complete cycle. When a current is said to be 60 cycles, it is meant that it makes 120 alternations per second. * • • What is meant by D. C.T By D. C. we mean direct current, or current that travels only in one direction continuously. Direct current is produced by a ma- chine called a dynamo. Alternating current is produced by an alternator. Steinway Concerts on Fridays at 3 P. M. THE latest improvement in the way of concerts to be heard from WJZ is the broadcasting of the weekly concerts held at Steinway Hall every Friday afternoon at 3 o'clock. This was brought about by the invitation of the officials of the Steinway Company in New York City to the Radio Corporation- Westinghouse Station to install mi- crophones in the large concert hall. This new development will bring joy to the hearts of thousands that cannot attend the concerts but who, through the agency of radio, can lis- ten in when the concerts take place at the concert rooms. Many of the most famous artists in the world are heard at these con- certs, and as the capacity of any hall, no matter how large it is, is limited, this new development will allow an unlimited number of people to hear the singing and music with- out the anno va nee of travel. At the "Gee, Annabel!*! ain't it nice of them to broadcast That Ever Lovin' Pair* for our benefit. They know us, all richt." same time, people who never have attended concerts of this kind will receive education in a musical way. Radio Grows in Holland OF LATE there has been a re- markable increase in the popu- larity of radio throughout Holland. Several large broadcasting stations have been planned, and they now are broadcasting directly from The Hague, on a 2,600-meter wave length. This interest has sprung up rapidly, and is a direct result of the reports of the American and Eng- lish transatlantic tests, in which the American amateurs did such re- markable work. Over the Water A stock company has been formed in Sweden, with a capital of $170,000 to broadcast news, market reports and entertainment from Stockholm. Remarkable interest has been shown in the new science, as evidenced by the generous purchases of radio goods throughout the kingdom. Subscribe for RADIO WORLD. $6.00 a year, $3.00 six months, $1.50 three months. Digitized by Google

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RADIO WORLD 27 World Conditions of Today Broadcast The main addresses delivered at the fifty-first annual dinner of the Silk Asso- ciation were broadcast from the grand ballroom of the Hotel Astor, in New York, between 8 :30 and 9 on the evening of Saturday, Feb. 3, on 360 meter wave by WJZ, the Radio Corp.-Westinghousc Station. The speakers were S. S. Mc- Clure, the writer, publisher and editor, VARIOMETERS Win S'/i" Oit ROTORS— Mas. Statin. SeaelaJ * CA ■raw, Caataat Baakleee, 230 ta (00 Matara. Prompt Attention to Mail Order* B. E. JAR VIS, Inc. 1 1 J- 1 13 Meakaala Stratt Nreark. N. J. American Radio Stores Double Circuit New W. D. 11- Tube Set, with A & B Batteries. Inside 13*7. Golden Omk Cabinet. Complete with tube and phone*. Tested Before Mailing. SPECIAL, $30.00 Attach Antenna and Ground and get DX. TUBE SET 1 Rheostat 1 W. D. U Socket 1W.D.U Tub* 1 Grid Leak Coodenaer 1 U" Battery. 0% volts 1 "A" Battery, dry call 1 Varioeoupler 1 *W Plata Condenser Who tar Hook Up Frao |Ja« f PA 1 Panel, TfcsMK Xl S-«™ Hook-Up Only Oron with Sat t"! *J_ Double Slid* Timfa* CotL List Price SIS*. Spade! fLM Hydrometers, Vary Special M R. C M. Variocoupbr, IN to M Maters »M National Hasdsats 4.TS Federal Hasdsats M» Mshegany Fbnahed Cabinet. TssH. Special JO Formica Panal to Fit M Mahogany Finished Cabinet, Hand Robbed. rfcxS* U* Formica Panel Cut to Fit Cabinet.... US American Radio Stores 235 Fulton Street, New York City An and Alexander Woollcott, well-known dramatic critic, now with the New York "Herald" and formerly with the New York "Times." Mr. McClure is a world traveler, and spoke on "World Conditions of Today," from a first-hand knowledge of many countries and public events. Mr. Woollcott, as interesting a speaker as he is writer and critic, talked on "Behind the Scenes." The toastmaster of the evening was James A. Goldsmith, President of the Silk Association of America. The Silk Association is a fifty-one year old trade organization composed of firms in every branch of the American silk in- dustry, from those who import raw silk from Europe or the Orient to those who manufacture, dye and finish fabrics. The association acts as a clearing bouse for trade problems and a center for the im- provement of the industry. The dinner was attended by more than 1,200 men. The guests included a number of the foreign ambassadors from Wash- ington, and distinguished delegations to the exposition from Japan, China and Great Britain. At ten o'clock the com- pany adjourned to Grand Central Palace for "Embassy Night," the private and formal opening of the exposition. Telling How It's Done The WJZ program for Sunday evening, Feb. 4, included a talk on "How the Waldorf-Astoria Concerts Are Broad- cast," by Dr. William H. Easton of the Westinghouse Electric & Mfg. Co. This address was broadcast, thus enabling both the invisible and visible audiences to hear the WJZ's broadcasting problems. Mexico's Service for Mariners THE Mexican Government inaugurated on November 1 last a new service of picking up and broadcasting notices to mariners emanating from foreign radio stations, American and Cuban. The notices will be broadcast for three consecutive days at 12 o'clock (local time) as follows: The radio station of Tampico will pick up for broadcasting notices emanating from stations situated on the coast between Florida and Rio Bravo and also from Cabo San Antonio radio station of Cuba. The Merida and Payo Obispo stations will broadcast notices emanating from the Cuban stations and also those of the coast up to Colon, Panama. The station of Sauna Cruz will broadcast notices emanating from stations situated on Ln n super- • lie I\e CRYSTAL Tee Vacuum Tube's Only Rrral" Will Mat* Vaer Cryual Oat lull Life Sea Base— 50« lata. RrSo aa« R. f. CoilaH li t*. JAYNXON LABORATORY 37 OCV STRUT. NIW YORK CITY Attention! Fans and Amateurs! Have roe tmflt roar owa raestterf Are roe aTpcrimoartag with any s tfr— If book- op } Are roe improving year self Are yea dome any tatersstiag i tive work m radio F j^^g^^^ Aeweonds of ereflaer /ana RADIO WOULD reery week' We want pictures of i seal Hag sets wttb descriptions of bow yea evercsme soma Unseal ty, or el any addMooal pert or aah that yea have added to obtain better remits. These srs the things that, prob- ably, the other (allow Is leoUag tor. Ssad in year information! pktuiss or what- yea have done to Improve the art. ssbor the beginner Is " We bars lowed a newer or hatter way el lens. Sand in a photograph el year set with or wfthoat sccom Denying diagrams sad mtaasnmaal State whether yea Scare m the picture ronreeH, or not. sad with- out aay cjrpoaoe whatsoever to yea we wO make aa engraving sad puhnsb it. Be sure to write your earns and address plainly on peotogrape. 1 m toot picture at sees, or If you net made a set or done saythtag a nuking radio material. teS tat est door all about this ewer. S,,|li i aa RADIO WORLD. 1493 boy Dttxt Eafeer . New York City, N. Y. the coast between Balboa, Panama and Rio Suchiatc. The stations of Hcrmosillo and Mexicali will broadcast notices emanating from stations situated between the Mexican Ixmndary and San Francisco. HERBERT M. HILL, Dept. D, taenia. W. I. RADIO MAILING USTS lt.41* RaS). Oman, an arise U. a. ar Btataa, aw M A1M 1.(14 Raela UTra. erwrlst U.S. by sums, mr list. I It.** 1.717 Real* set*** Jaseara, emrls* U. aVnr Stetaa. ear Hat III.** Ht Raata ttetleaa, par llat S4.es »»7 Urn. arte uake tad aaatwew nntliU Raela Seta, mr list 14. tt IS.SSt RejK Aaatesr* sad Msaassti ef Reaie l«S W. ADAMS STRUT OHICASO. ILL. D X Records ar* aiada with 6000 Ohm N&K Phones (LIM prlae III St) talrber aluaasa than anj ether pa Sale Price $7.75 rl* br all rallabl* dealer.. Daal.ra. pboo. or wrlta for «*dal prapailllan. National Radio Distributing Co. ( I wit. W I SI West Htk Street Chillis Rsl What You Should Know W» hsr« cpr-nt wtrr f 3.000 In ri— arch and •■- f«>rtru«ntaJ wurti trvl now aBrt threw simpl* sad ffflrit-nt radio circuits whtrh w» h**w fount! to ba- th.- Use for Inml «nriwinf Irwluttcw rtreult for two itu* solio Um yxMjr (wvwtit •'«•>• i«rti nsns or bur whfvrj row Ha*. ORDER TODAY ROBIN ENGINEERING OOMPAMY an Weet 4Mb Street New York GALENA CRYSTAL mounted in specially prepared metal 3Sc Unmounted 25c. AO fuarun- teetL Manufacturers, Dealers and Jobbers write for quaatity prises. It V also manufacture Radio Paris to order Precision Tool Sc Mfg. Co. IK Lewis Street. New York A B C of ■r capt. v. w. PAoi _ kaaa. prlaa'plai at artattoe, wib tmm a lalliaa or atrial N. la nada aad ehr H Saaaa la Un sir. Deelbe tav as alralu. SUa, II akee. la ea. tall U. dlffmat pana * aa Uralaae. are aad enet ibar da Danaikaa aJI tram ef ov* plaaoa aad hae am HBrr I. emrtrailaa; aa eel aa dKalOac dM Id'uut. tod (flaadaaaaaam «f «tm«t trpaa at almfl It larlnda. a amt- SMa dblleaarr at arlailoe (area aad dear em- lata at Ua.Iin« alrplaora TW raadw artll fad atari. laMrwInoa Mr ancaetuit. aMtlas as aad lianas alnlaaaa. A full daarrlpUM at alrrHat •notrol prtnci^u. I. ri>aa aad aetaeei af anas ar. fl»ro,«.o at Unrth Ttua tmek aa—ara mrr oamtaa ea* an ant abaui andm tintmlt. Ikrlr neainvilaa aad aawa- daa. IT'S pane. II* apwt.Dj Bad. IHistraUM wll» T plaiaa. rtla. II H THE COLUMBIA PRINT •UU ■■ lasViai. New York Oty DiyiLizuU Uy V^jOOgLc

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28 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? DEPARTMENT AT fa A WORD TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department is intended for everybody who wants quick action on short announcements corerins the bnrinst exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that Up w to read 2Sf EX^T. ..TV*^ WW ff * * teamd*J IT** copy received for this department will appear i^RADIoN on the news-stands ten days after copy reaches us. inrJ^Ll^JZ^ti^10 WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is 5c per word (minimum of 10 words, kdn'hag address), 10% discount for 4 consocutrre hsortkme, U* for 13 consecutive insertions 0 months). Changes wiMbt^U N ^C^hi*VBery«aBV'4^»6)OPy " ** **" **** pubUc,tion- WORLD COTw^roadwrnj! POCKET RADIO SET Talk of New York Radio Show. Super- fin* crystal. Patented tuning coil. Just the thing for hikes, bicycle trips, etc. Send $1.00, cash or M. O. J. DEMLER, lil Sherman Ave., N. Y. C RADIO BUILDERS AND BUYERS! Send 50c for (1) Any hook-up or diagram to meet your special needs. (2) Any special or general in- formation in answer to your questions. R. F. CHASE, 29 Bradlee St., Dorchester, Mass. FOR SALE— BROADCASTING STATION WGAM A 15-Watt Transmitter with a wonderful rec- ord. Has been heard in 10 different states. Com- flete set, mounted in Cabinet, four feet high, fcture and full details mailed to any one in- terested. Reason for selling, larger Broadcasting Station being installed nearby. A real bargain. Act quick. Orangeburg Radio Equipment Co., Orangeburg, S. C ASTONISHING RESULTS, ROKAY SINGLE CONTROL HOOK-UP. Don't buy, build or change your receiver until you get particulars. ROKAY ELECTRIC COMPANY, INGOMAR, OHIO. 4 INCH HARD FIBER RADIO TUBING, any length to 4 ft. 30c. per ft. Variocouplers $&25. Radio Assembly, 1109 Valley St, Poplin, Mo. AMATEURS— LOOK I Send in 15 cents to RADIO WORLD for issue of January 20 con- taining panel layout, hookup and full explanatory data on the construction of a D-X receiver, which simply lays the long distance on your table. Or start your sub. with that iassue. RADIO WORLD, 1493 Broadway, New York City. STUCK?— Let me solve your Radio reed vine problems. Service charge, 25c per question. Fred, crick Barber, 216 Jasper St., Syracuse, N. Y. HAVE YOU SEEN ITT My unusual fully il- lustrated radio catalog is complete. Only • dune. N. E Ristey, Spring Grove, Minnesota. MAKE MONEY AT HOME MAKING TOYS and novelties. Send 5c for samples and particu- lars. New Specialty Co., 417 E. 71st St., New York. HIGH GRADE engraving done on your radio panels at reasonable and attractive prices. For particulars, address T. Johnson, 15 Rosemont Rd., Worcester, Mass. FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO." Write today for complete list of premiums and our special sub- scription offer. "RADIO," Pacific Bldg., San Francisco, Cal. PHONES, TRANSFORMERS REWOUND. L Werts, 409 Saint Julian St., Pekin, 111. BROADCASTING MAP of the United States appeared in RADIO WORLD No. 8. Sent on receipt of 15c, coin or stamps; or Itart your subscription from that number ($6.00 for 52 issues). RADIO WORLD, 14*3 Broadway, New York A COURSE IN MECHANICAL DRAWING— By Louis Rouillion. The author has written • most practical book on the subject of Mechanical Drafting. It fully explains the art of Drawing, Lettering and Dimensioning. It is, by far, the most practical book ever published on this sub- ject, for use in day and evening schools, and more especially adapted for the teacher and for self instruction. Fifteenth edition, revised and enlarged. Fully illustrated. Oblong. COLUMBIA PRINT, 1493 Broadway, N. Y. G Pries, tLSL PATENTS — Inventors should write for Free Guide Books and Record of Invention Blank be- fore disclosing invention. Send model or sketch of your invention for our Free opinion of its S rentable nature. Radio, Electrical, Chemical, echanical and Trade-Mark experts. VICTOR J. EVANS & CO., 924 Ninth. Washington, D. C RADIO TUNING RODS (Pofent Applied For) Eliminates body capacity when tuning In. With Tuning Rod In your hand yotf can atop unnecessary noises and shrieking. Every radio fan should have Radio Tuning Rod. Send ?5 cents stamps or money order. Radiophone Co.. 505 Fifth Avenue, New York City. WESTINCHOUSE RA Tuner, $45.00. WU1 trade for Underwood or Corona Portable typewriter. Raymond Schlegel, 1118 N. Negley Ave, Pitts- burgh, Pa. SUPER-SIMPLCITY CIRCUIT Hear Europe, Asia, Africa and Australia's Ions- wave stations and LOCAL broadcasting, on ONE TUBE, one control. 'NO rheostats, storage bat- tery, variocouplers, variometers, three-coil mounting, variable inductance, taps, switches, dead end losses or radio frequency. Cuts, hookup, everything. Nothing to guess about. Price $1.00. RADIO EXPERIMENTAL LABORATORY. Box 194 A, Berkeley, California. VACUUM TUBE RESULTS WITH A CRYS- TAL SET! Use a ,rPT" Ultra-Sensitive Contact in your Crystal Detector. Beats gold and other ordinary catwhiskers. Myrle Wood, Rhinelander, Wisconsin, writes: "That *PT* Ultra-Sensitive Crystal Detector Contact I purchased is sure a wonder. Using the *PT* Contact and galenaT~I have heard over 43 different broadcasting stations, up to 1,000 miles distant." The "FT" has re- ceived over 3,300 miles, when vacuum tubea failed. Price only twenty-five cents. "PT" CRYSTAL CONTACT COMPANY, Box 1641. BOSTON, MASS. . MILLION POINT TESTED CRYSTALS — Mounted in Woods Metal. These Adbrin Crystals are tested and are guaranteed or money refunded. With so many sensitive points, it is impossible to miss contact. Stop wasting time and send ns 30c for one Adbrin Crystal or aend $1.50 for six, mailed prepaid. Also write us for information as we have other styles, including our new type combination twin Galena and Rariocite. Diolite Radio Panel Boards, insulated, rubber base, cut, bored and drilled with ordinary tools without spoilage. Sixes can be furnished cut to your re- quirements up to 22x21x3/16. Write to as for prices or ask your dealer. DIOLITE IN- SULATOR CORPORATION, 287 New York Ave- nue, Brooklyn, New York. MODEL MAKING— By Raymond Francis Yates. 'A new book for the mechanic and model maker. This is the first book of its kind to be published in this country, and all those interested in model engineering should have a copy. The first eight chapters are devoted to such subjects as Silver Soldering, Heat Treatment of Steel, Lathe Work, Pattern Making, Grinding, etc The remaining twenty-four chapters describe the construction of various models such as rapid fire naval guns, speed boats, model steam engines, turbines, etc. 400 pages. 301 illustrations. Price, $3.00. The Columbia Print, 1493 Broadway, New York City. ATTENTION, Amateurs 1 1 Have you seen the RADIO WORLD'S page of hook-ups in the Oct. 21 issue? 15c a copy or start your subscription with that Number. Many people are writing in tor the hook-ups listed here. RADIO WORLD, 14*3 Broadway, Now York City BEND TJ8 THE NAME OP YOUR RADIO CLUB *™M. °f J°Ur «w«lo>nt «a other officers. We want to add these to a list of w1,,RLDn^4.VBro?^«y.WS.;reToAParl,,* f°r *UM!C"'» '» » >— • RADIO MAKE MONEY silvering mirrors, .uj kfaHi plating, knives, spoons, auto headlights. Outfits furnished. Free booklet. International Labora- tories, Dept. 310, 311 Fifth Ave., New York. FOR SALE— Grebe CR-8, complete, $75.00; stor- age battery, $10.00; two-step automatic ampli- fier, $25.00. New, guaranteed bargains. Irvin Mauer, Bethlehem Prep., Bethlehem, Pa. CASH FOR OLD GOLD. Platinum, Silver, Diamonds, Liberty Bonds, War, Thrift, Unused Stamps False teeth. Magnets Points, Jobs, Any Valuables. Mail in today. Cash sent, return map. Goods returned in ten days if you're not satisfied. OHIO SMELTING CO.. 137 BBs- podrome Bldg., Cleveland, Ohio. EXCHMHU JOLLY INTERESTING LET, £ERS through oar club. Stamp appreciated. Betty Lee, Inc. 4254 Broadway, Mew Yort CHy! NEWS AND GOSSIP OF THE STAGE — Send 10c. for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $440 year, $2.00 six months, $1.00 three months. New iork Star Co., 1493 Broadway, N. Y. OLD MONEY WANTED — $2.00 to $5*1.00 EACH """.(P* hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Blnatrated Coin Value Book, 4x6. You may have vahtsble com.. Get posted. We pay CASH, darks CoS Company, Ave. 13, Le Roy, N. Y. WIRING A HOUSE. By Herbert Pratt. Show, a house already built; tells just how to start about wiring it; where to begin; what wire to use; how to run it according to insurance rules; in fact, just the information yon need. Directions ao- &a~£S8&J°.*1 ^ho°- S«tJ» edition. COLUM- |fA*RINT. 1493 Broadway, N. Y. C Price, EXCHANCE LETTERS with friends everywhere. Pleasant pastime. Information for stamp Smith. Box 3125, M. Portland, Ore. B?Tp^TRDvrELECJRICAI-, DICTIONARY— By Prof. T. O Conor Sloane. Just Issued an en- i 7 nV edltlon brought up to date and greatly enlarged— a. a reference book this work is beyond comparison, as it contains over 700 pagea. nearly 500 Illustrations, and definitions of about «S» distinct words, terms and phrases. The defini- tions are terse and concise and include every iS™. "I**1 "> ^electrical science. 767 •ages. 477 dlustrstions. (See page 18 for fuller description.) rlewNorkaly1' Prinl- »«» Broadway. TWENTIETH CENTURY BOOK OF RECIPES. FORMULAS AND PROCESSE^EdJtrf bycZS ner D. Hiscox. This book of 800 pages is the most complete book of recipe, ever published, giving thousands of recipes for the manufacture of valu - oble articles for every-day use. Hints, helps, practical ideas and secret processes are revealed within its pages. It covers every branch of the useful arts and tells thousands of ways of ma kins money and is just the book everyone should have at his command. The pages are filled with mat- ters of intense interest and immeasurable prac- tical value to the photographer, the perfumer, the painter, the manufacturer of glues, pastes, cements and mucilages, the physician, the drag- gist, the electrician, the dentist, the engineer, the foundryman, the machinist, the potter, the tanner, the confectioner, the chiropodist, the man- ufacturer of chemical novelties and toilet prep- arations, the dyer, the elect roplater, the mssiolcr. the engraver the glass worker, the gold. beater, the wstchmsker, the jeweler, the ink manufac- turer, the optician, the farmer, the dairyman, the paper maker, the metal worker, the soap maker and the technologist in general. A book to which you may turn with confidence that you will find what you are looking for. A mine of information up-to-date in every respect. Contains an im- mense number of formulas that everyone ought to have that are not found in any other work. New edition. 807 octavo .pagea. Cloth binding. Price, $4.00. The Columbia Print, 1493 Broadway, New York City. Digitized by Google

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RADIO WORLD 29 Editor Discusses Kellogg- White Bill THE government has found it impossible to properly regulate the radio opera- tions of 1923 through the provisions of an act passed in 1912, says the Norfolk Pilot in an editorial discussion of the radio con- gestion. The provisions of that act may have been satisfactory ten years ago, when amateur stations were a rarity and broad- casting stations unknown; but at a time when the country contains twenty thousand transmitting stations and more than five hundred broadcasting stations the old law is ridiculously inadequate. The Department of Commerce, by the adoption of regula- tions not inconsistent with the Act of 1912, has tried to keep pace with the advance of wireless, but the department has been sadly encumbered by archaic limitations of authority. The result is such a congestion in atmospheric traffic as to render receiving apparatus at times almost useless and to endanger the essential uses to which radio is put That stricter regulation and a new effectual assignment of wave-lengths to sending stations are necessary for the future of radio is evident to any owner of a receiving set who has listened helplessly to a medley of grand opera, stock reports, bedtime stories and political speeches. A step in the direction of more effective regulation has been taken through the in- troduction in Congress of the Kellogg- White Bill for radio control, hearings on which have begun in the merchant marine committee of the House. This measure, the result of study by radio experts and Depart- ment of Commerce officials, is hardly the last word as a remedy for the conditions which prevail, but it has features which commend themselves as worth trying. Its most significant provision is that which grants the Secretary of Commerce the power to classify radio stations, to pre- scribe the nature of service to be rendered by each class of station and to assign wave- lengths. In this he is aided by the amend- ment which removes the old restriction on wave-lengths, except for army and navy stations, to less than 600 or more than 1,600 meters. Twenty thousand transmitting stations and five hundred broadcasting stations cannot satisfactorily be limited to wave-lengths of between 200 and 600 meters, and that was virtually the effect of the limitations of the old law, for 1,600 meters is too great a wave-length to be practicable. The license fees provided by the Kellogg- White Bill would probably have the effect ,of reducing the number of stations. The provision which gives the Secretary of Commerce the power to grant licenses only to stations which are "in the interest of the general public service" would work to the same end. The Secretary of Commerce js given wide discretionary powers which, if used wisely, would effect a welcome clarifica- tion of the existing radio confusion; but which, if abused, would militate against the amateur radio fans who have done much to develop the science in this country. Legislation looking to the regulation of an industry as new as radio is in a virgin field, and the probability of error is high. The Kellogg- White Bill is probably not free from unwise provisions, whose unwisdom will not be discovered until it has been passed and put into effect. Its clearly sound provisions are so many and its debat- able ones so comparatively few that the measure seems well worth enacting into law. A start has to be made in bringing order out of the present radio chaos, and no better plan than the present one is in sight. Meteor Appears THE officers of the Meteor Radio Club, of Leland, Florida, are: President, Horace Williamson; secretary, Arthur Radio Station Blown to Sea A REPORT received by wireless at Anchorage, Alaska, declares that wind has demolished the naval radio station on St. Paul Island, in the Bering Sea. The report came from the Steamer Starr. The naval radio station on St Paul Island is used for relaying messages to Japan by the northern route and plays a large part in the trans- mission of marine intelligence. ELKAY RADIO PHONE From Factory to Yea 3RD ohms adjustable head- band, 5 foot cord, every phone guaranteed to give entire satisfaction, or money refunded. Equal to any (8.00 phone on the market. Subscribe for RADIO WORLD. $6d09 ■ year, $3.00 six months, $1.56 three i SXSt postpaid, C O. D. or Money Order. The EBny Co., 207 Market St., Newark, N. J BARGAINS EVERY DAY 11 YEARS ON TOT SAME SPOT LOOK AT OUR PRICM: Dictograph La. Bsseksrs $ 1 3.2ft Dietwrash Pksew 4.71 Phone Pluji ss Lawsaat 2-Sllds Talis tells. . 1.85 Wsstsrs Els*. Pastes 7.50 DsFsrsst Radio Hobo Stalls Tibs Sets 11.50 ■™ °™* ii.ii asters jTSSTilsss snstsss. mm- \ g-'HSL11" * "J** Afus ww zir , i - *o-pibio 4.oa All vsstHim Turns rsjainea. Autb. Phones $3.00 W. D. II sockets .43 Bakelite V. T. sesasts St Freshman VvisMs Grid Leaks. .«• 3 -layer bank wound soils-— silk wire, Iskslrss tubs 3000 .. 2.75 Mail ordert on receipt of SUNBEAM ELECTRIC CO. 71 THIRD AVE. (Bet. 11th and llth Sta.) NEW YORK WALCON Radio Frequency Transformers Brines in distant stations on a loop— perfect reproduction. No Particularly THE BEST YOU CAN BUY WALCON Transformers are tested and guaranteed, adapted for use with W.D.ll tubes. Four new hook-ups, including a new reflex circuit furnished without charge with each transformer. Price, $4.00. We pay postage. Dealert and jobbers: Write for our attractive sales proposition, backed by national advertising. Manufactured by THE RADIO CENTRE, 2 W. Broadway, N.Y., N.Y. DELICATE SOLDERING Both the manufacturers' and amateurs' problem on all fine work ia readily soWed by the instrument eonitructed for this particular purpose. THE POST SOLDERING IRON Platinum Heating Unit^-Interchangeable Tips— Universal Current (Lara* and Small) A ONE-HALF ACTUAL SIZE $6.00 Prom Tour Dealer or Write Awarded Certificate of Excellency, N. Y. Evening Mail Radio Institute POST ELECTRIC COMPANY, (Dh. 509) 30 E. 42nd St, New YoA FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City. Please tend me RADIO WORLD for months, for which please And enclosed $ SUBSCRIPTION RATES: Sin** Cow, * » Tare* Months X.S0 St* Months 3.00 On* Year (SI Israel) 6.00 Add ttOO a Year for Foreign Postage, 50c for Canadian Post Digitized by Google

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30 RADIO WORLD Here's Your Radio Library! Useful Technical Articles Published in Former Issues of Radio World APRIL 1. A 500- Mil* Radiophone Bknploylng a 5-Watt Tub*, by Frank A. HahneL "Tall Me, Please. How WUI Thto lot Re- ed veT" by B. L Bragdoa. Short Cute In ReeelTsr-Clreott Design, by O. O. Rom. Making • Short -War* Regenerator, by Fred. Obaa. Ehlert APRILS. Do Tea Know Tour Reostvtag BqiilnrneBt. by James D. Gordon. Way a Crystal la Callad a Rectifier, by Wal- la Radlotelephony DapaadablaT by O. C. Mounting Crystals la Tonr Detector, by B. L Bragdon. Btoraga Battarlaa tor Radio, by Fred. Oka*, mart APRIL U. Pint Prtaelpleo of Blectrictty aa Applied to Radio, by John P. Miles. Tonr Storage Battery, by B L. Bragdon. What Makaa Radio Possible, by Rdward Ida- around Ooaaoottaa aa Vital aa aateaaa, by Fred. Obaa. Bhlert APRIL ». VataaMa Pointers on Aarlal Construction, by Bdward IAnwood. What to at out by Tuning, by B L Radio-Frequency Amplification and ration, by Prank Araatroag. Honey-Comb Colli and Ooadaaaarm, ward Llawood. Charging by Storaga Battary, by B L Row to Conatmot tha Vartoeoapler, by Fred- arlek J. Romford. MAT 0. no Adraatagee of Radio Praqnanay, by Harold R Pottar. Bow to Construct, Protoot aad Operate a Storaga Battary, byOeorga W. May. Tha Begtaaer'e Catechism. byRdward Ua- Tuning and What la Meant by It, by Chaa. ■alert. New Frequency Amplifier Brlaga With In Strong, by O. W. May. MAT 13. My Practical V. T. Detector and Two-Stage Amplifier, by Frederick J. Rumford. The Principle! of Radiotelegraph/, by Wal- ter J. Howell. The Reason for the Loop Aerial, by Oeorge W. May. Tuning and What Is Meant by It, by E. L. Bragden. The Beginner's Catechism, by Edward Lin- wood. MAY 20. The Design of an Amateur Receiving Set, by C. White. The B Battery and the Plate Currant, by Oeorge W. May. Radio Terms at a Glance, by Fred. Chaa. Bhlert. Tha Baglaner'a Catechism, by Rdward Lda- wo~1. Fire Underwriters' Rules, by Fred. Chaa. Bhlert. ' MAT ST. Tha Beginner's Catechum, by Bdward Lla- wood. How to Make Tour Own Condenser, by Oeorge W. May. Tuning aa Applied to Telegraphy, by Walter J. Howell. Why the Condenser Doesn't Condense, by B. L Bragdon. Making Signals Loader with Two- Stag* Am- plifier, by Oeorge W. May. JTTNB 8. Tha Cost of a Stogie-Circuit Receiver, by Howell W. Millar. Tha Beginner's Catechism, by Rdward Lin- How to Compute and Build a Fixed Con dea- ler, by B. L Bragdon. ^ Dorian^ for an Amateur's ReoslTlng Sat, by Simple Method of Recharging a Storaga Bat- tery, by John Orayaoa. JTTNB 10. Radio ReoslTsr for Short Wares, by Qeorge W. May. How to Filter Atmospherle Conditions, by 0. White. Tha Messenger Boys of Broadcasting, by B L Bragdon. Are Ton a Member of the N. O. D. C.T by B L Bragdon. The Beginner's Catechism, by Bdward Lla- wood. How to Construct One- and Two-Slide Tuning Colls, by Oeorge W. May. JUNE 17. The Vacuum Bulb's Start In Life, by C. White. How to Select the Right Set, by B. L Brag- don. The Bert niter's Catechism, by wood. Bdward Lin- Test of Induotanee Colls, by Bhlert. Short Wavee from a Simple Receiver, by Stanley Bryant. ' JTTNB 94. How to Make Tour Radio Cabinets, by W. S. Staadlford. How the Crystal Detector la Dead to tha Beat Advantage, by C. J. Williams. How to Construct a Long-Ware Regeaera- tlre Receiver, by Oeorge W. May. Tested Invention of Major Armstrong Aanll- Oaa Sat 100.000 Times, by Joan Rant Repairing Cracks in Hard-Rubber Btoraga Battery J are, by W. S. Btanditord. Tha Beginner's Catechism, by Bdward Lto- JTJLT 1. Novel Unlt-Deteotor aad Ampullar, by Fred- erick J. Rumford. Why Ton Must Dae a Ooadaaaar, by C J. Williams. How Wave Lengths Travel, by Fred. Chaa. Bhlert Radio World's Revised Dictionary, by Prad. Chaa. Bhlert The Beginner's Cataohlsa, by Bdward Ltn- Oaa of the Vacuum Tuba Dataotor, by W. May. JOLT 8. Radlo'a Ptaoa la tha Phenomena of Nature, by R U Bragdon. The Puaotlon of tha 1 H. Plata. Armstrong's Fully Iplalaad, by John Kant Operating a Transatlantic Station, by Fred. Chaa. Bhlart Tha Beginner's Osteon lam, by Bdward Lra- i Lagan Coupler, by Chcrtss Reducing Strays aad Static, by Bhlart JOLT 15. Assembling a Detector and Two-Stags Ampli- fier, by H. 8. Stanford. Combined Radio and Audio Frequency Atnpii- fleatlon, by C. White. The Beginner's Cataohlam. by Bdward Lla- wood. Locating Tour Aerial, by Harold Day. Facta for Beginners, by Prad. Chaa. Bhlart JOLT 22. When Tour "Movies" Come by Radio, by Stea- ler Bryant. Underlying Prtnctplea of tha Vacuum Tabu, by Oeorge W. May. Practical V-T Dataotor Paasl, by Frederick J. Rumford. Revised Radio Dictionary, by Prad Cass. Rhlsrt Tha Beginner's Catechism, by Bdward Han and Importance of Aerials to Radlatloa, by C. White. JOLT SB. Tha Vacuum Tube aa a Transmitter, by Charles H. Plata. My 20- Kilowatt Tuba aad Its Uses, by Irving Langmnlr. Importance of the Capacity Switch, by B L Bragdon. The Truth about Harold R. Hart AUGUST 5. How to Construct aad Operate tha Ai Superregeneratlre Circuit, by John Kent Using Radio Frequency to Extend Range, by Lamp- Socket Aerials, by Oeorge W. May. Things Every Radio Fan Must Know, by B. B. Hawley. Revised Radio Dictionary, by Prad Charles Bhlert AUGUST 13. The Work of tha Audio-frequency Transformer, by Oeorge W. May. Practical Measurements of Capacity and la- ductance, by W. A Dickson. Experimenting with Armstrong Circuit Pro- duces Unusual Hook-up, by Dr. O. S. Kelly. How to Secure Perfect Regeneration, by Prad. Chaa. Ehlert AUGUST IB How to Build a Portable Field Bus Mr, by Da Witt H. Thompson. Using Two Tubes for Receiving, by O. White. The Storage Battery as an Important Factor In Radio Reception, by Donald Van Wyok. The Use of Capacity la a Circuit by George W. May. The Beginner's Catechism, by Bdward Llawood. AUGUST 98 How to Build a Spider- Web Receiver, by Frederick J. Rumford. My Detector and One-Step Amplifier, by Prad. Chaa. Ehlert The Beginner's Catechism, by Bdward Lla- wood. Hints for Fans, by C. F. Rye. 8BPTBMBER 2 Generating C-W for Transmission, by O. White. Wonders of Radio-Frequency Amplification, by H. 8. Potter. How to Connect the Electric-Light Socket Aerial, by John Kent Practical Circuits for Regenerating Load Sig- nals, by O. B. Kelly, SEPTEMBER 0 Radio Ideas for the Amateur to Teat Oat by Carl Masaon. How to Make a Practical Wave-Meter, by Frederick J. Rumford. How to make a Hooey-Comb Coll with a Stage Amplifier, by Fred. Chaa. Ehlert Perfect Short- Wave Radio- Frequency fleatlon, by George W. May. 8EPTEMBER 16. How to Make a Two-Tube SuperregeaersAar. by Frederick J. Rumford. Methods of Amplifying Radio Signals, by R Bradbury. Volos Distortion la Vacuum-Tuba Recarreca. by W. A Dickson. Charging a Battery— from a Franc; Point of View, by Marina Thouvaia. Work lag Diagrams for Beginners. SEPTEMBER 2S, 1922 pNew J^T^Hook-np Worth Testing Oat, by 'New Method for Lighting Filaments, by C White. _ Why the Radio Compaaa Is the Fighting Element of Science, by Ortberaa Gordon. Complete Table of symbols Used la Radio Reception, by Fred. Chaa. Bhlert The Radio Primer, by Bdward Llnvrooa. Complete Method for Building an Electros Tube Detector Unit, by Bxperta of the United States Bureau of Standards. SEPTEMBER SO, 1933 Increasing the Wave Lengths of a Reeatv- tngSet, by Oeorge W. May. The Importance of the Variometer to a Re- ceiving Set by Donald Van Wyck. Successful Stunts of an Amateur by C. P. Rye. Employing lacks with a Two-Stage AaapU fying Receiver, by Fred. Chaa. Ehlert OCTOBER 7. Superheterodyne Receiver as Applied to the Arm strong Snperrt generative Circuit, by Charles S. Lents. Constructing a Radio- Frequency WsgaaasaUi. by C White. " Why the Open Antenna Is Best for the Raew Listener, by C D. Wagoner. Broadcasting Stations of United States sad Canada. The Radio Primer for the Beginner, by Lyes Brooke. OCTOBER 14. Neat Home-Made Tube Socket, by Gordon 8. Arthur. Vessels Now Guided Through Fog by New System of Radiotelegraph/, by Otherua Cardan . What Makes the Receiver Work, by Donald Van Dyck. Using the Vsriocotrpler in a Short-Ware Re- ceiver, by George W. May. Regenerative V-T Receiver for Short Wares, by Fired. Chaa. Ehlert OCTOBER 2L important Improvements in Radio Receivers, by C White. Be Sure of Your Ground Connection, by Fred. Chaa. Ehlert How Radio Was Installed in Our Home, by Hattie Briggs Hart man. , One-Tube Regenerator Hook-up for Loud Sun. by Harold Day. Every Radio Set Has a Reliable Range, by Teas Kent The Theory of Radio Communication, by Horace Beers. OCTOBER 28. A simple Super-regenerative Receiver, by Har- old S. Potter. Vacuum Type of Arrester Safe, by Fred. Chaa Ehlert. How to Make Your Aerial Function, by Horace Beers. How to Avoid Interference When a 30 Meter snd s 400 Meter Station Are Operating Steal taneouily, by C W. Horn. NOVEMBER 4 Receiver for Amplifying Weak Signals, by Hcs- ece Beers. How to Learn the Code, by Ort herns Gordsa Detectors— snd How They Work, by Doaab) Van Wyck. One of the Most Delicate Parte of a Receiver, by George W. May. o W»»eMeter f„ Amateur Operators, by Unite* States Bureau of Standards Experts. NOVEMBER 11 How to Build a MO-Meter Concert Receiving Sat by Frederick J. Rumford. Wide field for Experimenting with Aerials, ay Donald Van Wyck. Single-Tube Superregenerative Receiver, by C White. Utiliiing Ford Spark-Colls for Audio- Frequency Transformers, by Ortherus Gordon. „Why It Is Necessary to Tune In, by Arthur G. Shirt. Any single copy of Radio World, be- ginning with No. 1, mailed on receipt of 15 cento postpaid. Any seven iaaoae for All 43 issues to date for SSJR Or send $6.00 for 1 year (52 numbers) aad hare your subscription start from No. t Radio World. 1493 Broadway, Now York Digitized by Google

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RADIO WORLD With the DX Nite Owls (Confirmed /rom. paing no grid leak. All my best work has been done on the 12- volt tap. If I tap a higher voltage my signals are mushy. This hook-up is certainly worth a tryout by any one, and Mr. Taulbee is to be com- mended for passing it along. Any inquiries would be gladly answered by me. ATr^METsT RocoW. $£.00 Rang* St to 509 MOm °" The linmi AIR-MUSE receiTcr contiiU of Oik cabinet, bakelite panel, selective and primary tuning-. So simple a child can install and operate it Broadcasting sta- tion, programs heard perfectly. Thi« re- ceiver is absolutely guaranteed or money refunded. Sent post paid anywhere in the U. S. A. on receipt of Express or Post Office Money order. WO Ohm double headset SSJ* Set complete as illustrated 12.44 All other radio accessories at manufac- turers' prices. Detroit Radio Company ONE WEST Mat STREET NEW YORK DssVt W SO MANY READERS ABE disappointed in not receiving theii copies of RADIO WORLD on tSM newsstands regularly, from week te week— due to early selling out bj dealers — that we suggest that yen place a standing order with yam newsman. Ask him to save you i copy of every issue. 185 GREENWICH STREET TUBES IN STOCK W D. 11-U. V. 2M and NEW YORK, N. Y. PHONES nnhirask 1000 Okan 14.43 federal 4.M Nn kturONk 300* Oka 4.IS BannarS S.4S PATHE MOULDED V * R 1 0 M FT E H S AND VARIOCOU SLEEPER RHEOSTAT. Lilt PrUe. tl 00. OUR PRICE W. D. II TRANSFORMERS .. a"b*V 1 CONDENSERS COUPLERS Si «s . l.tl 3 73 . 4.4S . 1 S3 . .tt Ml CUTTINO AND WASHINGTON 1 Tvk. | List Mat »" S22J>0 | CUTTING AND WASHINGTON ISl.ft Awsllfttr ae4 DilMtM. CCf) ■ »« »»» T21 SEND MONEY ORDER. INCLUDING POSTAGE— ALL GOODS GUARANTEED FRESHMAN PRODUCTS Accurate and Dependable VARIABLE RESISTANCE LEAK "MICON" TESTED MICA CONDENSE RS law Price ASSURE— MO S4-SS Accuracy tSf -IS Noteeleeaaeea •1 .4S Clarity of Tarn. 42 .44 Conalant Capacity WUft snfd. MJcoa $1.00 CUrtnes SI gaols Uabrokea Range. WltfcOMI 75c Zero ESaianatee His. big to Five Megohaaa .TS J44 Micons aad Variable Leaks especially adapted far use with new FT*w»Ding Super-Cb-cuft, At Y«if D»al*f» I. •I :■ ; < c.l CHAS. FRESHMAN CO, lac, 47 St, N. Y. Digitized by Coogle"

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RADIO WORLD IF YOU ARE INTERESTED IN RADIO YOU NEED THESE BOOKS BEST RADIO BOOKS Telling How to Operate a Radio Set— How to Build a Set — Principles of Vacuum Tubes and Other Radio Problems Radio Hook-Ups By M. B. SLEEPER A book that civet you not only clear dia- grams for all kinda of telephone and tele- graph receiving and traatamitting acta, but simple descriptions of each circuit shown and space* for notes of results obtained. PRICE Tec, Construction of New TypeTrans- atlantic Receiving Sets By M. B. SLEEPER There is a peculiar fascination about re- ceiving radio messages from the high- power nations of England, France, Ger- many, Russia and Italy, as well as those located in the Pacific Ocean and the Orien- tal countries. Several types of simple re- ceiving sets for this purpose are described, with detectors and amplifiers to accompany them. Suggestions are also given for oper- ating relays and reproducing the signals on a phonograph. Schedules of operating time for high-powered stations are given. In addition, there is some valuable data on home-made wavemeters for testing and ex- perimenting PRICE lie. -■-?jte, Wireless Telegraphy and Tele- phony Simply Explained By ALFRED P. MORGAN One of the most complete and comprehen- sive treatises on the subject ever published. A study of its pages will enable one to master all the details of the wireless trans- mission of messages. The author explains in simple language the theory and practice of wireless telegraphy and telephony. 154 pages, 156 engravings PRICE tlM Design Data for Radio Transmitters and Receiver s| By M. B. SLEEPER * The only book that fives tables and data for designing, receiving and transmitting apparatus so that you need no knowledge of mathematics. It's the first boost a be- ginner buys after he has learned the use of his phone receiver FMCEJc. Construction of Radiophone and Telegraph Receivers for Beginner t By M. B. SLEEPER The man who wants to feel the real thrill of accomplishment, and who is not satisfied in the merely making use of what others have done for him, builds his own radio apparatus. Radio men can follow the date in "Radio Phone and Telegraph Receivers" with full confidence, because each piece of apparatus described was first made, tested and found efficient before the final design was accepted. Special receivers, both crys- tal and audion. are shown in detail. Regen- erative circuits as well as audio and radio frequency amplifiers are described with clear photos, diagrams, and working draw- ings prepared especially for the novice and the man who wants to receive the radio telephone broadcast. A special feature is I radio set and the loud ..PRICE 7 Sc. The Radio Experimenter's Hand- book By M. B. SLEEPER Throughout the preparation of this book, one purpose was kept in mind— Answer the Practical Questions of the "Novice," of the "Beginner/' and the more advanced "Stu- dent" This book will help in the selection or construction of simple apparatus for the transmission and reception of radio tele- graph and telephone signals. In the chap- ters on radio receivers the simplest crystal, the simple audion, and the regenerative types are described in quite some detail. The question of antennas, both for trans- mitting and receiving, are taken up. A good many helpful suggestions are given which will be of considerable aid to the experi- menter. 16 chapters. Fully illustrated. PRICE si.se The A B C of Vacuum Tubes Used in Radio Reception By L a LEWIS Aawec. I. R, E., and Radio Instructor Written particularly for the person who "knows nothing about radio," but who would like to gain an understanding of tat elementary principles of operation of vac- uum tubes and various circuits in which they are used for the reception of radio- telegraph signals and radio- telephone mtuk and speech. Illustrated PRICE tm Books on Electricity Arithmetic at Elastrttlty. By PKOF. T. O'CONOB SLOAN*. A pnettnl treatise on elsstrioal sakalattona at all Hods n- duetd to a series of roles, all af the aUaplssI tea*, sad lnrolTina only ordinary arithmetic: cock nm Illustrated by one or sal MUM astaooB of each This of alaetnelty. omrutx sa It ... mathmatlos of eloetrlelty la a nuumsr last am attract the attention of those who tit not fulls; with altennucel formulas. ISO sans. New he- vised and ■marred admen. Prise. II. St By WILLIAM BAXTER JB. Ins bastasa as) of dynamo or motor of the dtreet-snrnnt type H the commutator. This book toss lata the malm- ulldtnf s bow to hi Inc. builduur and malnt allows bow By EDWARD TBKTKBT. This - praetleal directions far buudlnff a ra» H. r. Dynamo of the Edison type capable of ttfbttnf about fifty aatdsa lamps of the tv-watt sue. Is addition. It sins directions for buUduii las aaal electric motors soluble for rtmntnc cedes as- chines. The concluding chapter describes the «o- stroeuoo of a simple bichromate batten adspuc for runnlnc electric motors, (a oasts, ronj Illustrated with detail drawtacs. Oath. Prim. II.M D yearns Bolldlai for A manor*, or How ts Cee- strust a Fifty Watt Dyaame. By ABTHUB J. WEED. A praetleal matte) showlns In detail the construction of s assO dynamo or motor, the entire, machine vert ■ which can be done on small foot lathe. DUom- slonod worklnc drawings are siren for tech elm of machine work, and each operation Is deira described. This machine, when used ss ■ dim». has an output of fifty watts; when used si i motor It will drlre a small drill prem or lathe It can be used to drive a cowing inachlm oo any and 111 ordinary work. The book Is Illus- trated with more than slrty orlslnsl cwnrinp showing the actual construction of the duTmot pans. Pries, SI.M c;r Any of These Books Sent Prepaid on Receipt of Price). The II Books for $10.00, to One or Different Addresses). address THE COLUMBIA PRINT ROOM 326, NO. 1493 BROADWAY, NEW YORK Digitized by Google

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15c. a Copy February 17 $6.00 a Year &Z Numb.r. WORLD Bureau of Standards Uses Oscillograph to Measure Wave Length of Transmitters Accurately JL (C. Wide World Photo) The large number of transmitting sets now operating makes it necessary to have a means of aces measuring the wave length of different stations. This illustration shows an Oscillograph and fork, by which it is possible to photograph the form of an emitted radk> wave. It is thus possible to determine the wave length to an anuuring degree of accuracy. The Oscillograph is the square box shown in the left center of the picture. This apparatus, which is an American invention, is the most accurate measuring apparatus of its kind in the world, and is used by the Bureau of Standards in Washington Digitized by LjOOg IC

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RADIO WORLD BIND MS TOUR PHONES for repair*. All makes. Satisfaetlea cuaraateed. Reasonable charcee. mm, Mi wi **mt ■>, Raw Tan* cur CABINETS Hlnaed Top, Beautifully Rubbed Mahogany Finish. TxlS $3-S 7x21 SXSS JxZ4 tUI Aafc your dealer for the B.C. Type. R. C. MILLS M Cast 23rd Street New York City WIRING A HOUSE. By Herbert Pratt, saWwa a boute already built; tall* jut how to atari about wiring it; wbera to begin) what vire la use; bow to ran it according to insurance rales; ta fact, Just the information yon need. Direction! ap- ply aqnafly to a shop. SUrth edition. COLUM- BIA PRINT. 14K Broadway, N. Y. C Radio Comes to Relief of Snowbound Farmer FARMERS who were luke- warm to radio or who looked upon it as a diversion for the women and a toy for the children, are today convinced that radio broadcasting is a real utility. New York State, for example, was veri- tably buried under twenty-six inches of snow. The cities were able to cope with the snow after a fashion, but the country was practically iso- lated, especially after the wind churned up the snow and drifted roads as rapidly as shovelers and tractors opened them. MAKE YOUR OWN COILS WHITE CEMENT enable* you to wind your own self-supporting spider web coili, con- struct variometers, variocouplers, etc No distributed capacity. Prevents shrinking of wood. Holds windings securely and permanently. "It is only necessary to wind the coils on a core, over either paper or a layer of string, then coat the coil with the liquid, allow it to dry and after another coat remove the String or paper and the coil will be found to be self-supporting." — RADIO WORLD. AMATEURS: — Send 25c for sample bottle. DEALERS: — Write for our proposition on this new money-making proposition. WHITE RADIO COMPANY 12S EAST 23 RD STREET NEW YORE CITY Tested and approved 6y RADIO WORLD and N. Y. XVENINO MAIL. 4 "M1CON- THTCO MKA COKCtMStR FRESHMAN PRODUCTS Accurate and Dependable "MICON" TESTED MICA CONDENSERS Price ASSURE— USS Accuracy JS Nnfealsasiisse M Clarity of Too* Conetant Capacity VARIABLE RESISTANCE LEAK With JSCS mfd. Micro Without $1.00 CUrinea Signals n Range, Unbroken ' M$ Mloona and Variable Resistance Leaks especially adapted far use with new FleweBIng Super-Ch-cort. At Ysur Dalari — Othanrlee Hid purehsM price and you will be supplied postpaid. CHAS. FRESHMAN CO, lac, « St, N. Y. STANDARD RADIO APPARATUS wmnm Every item listed in this advt. is guaranteed by us to be new and in original cases. Our guarantee of satisfaction or money refunded still prevails. ■n A n s~i k -armm Dlrteireph Loud Speak en SIS. 00 K easier Oondeoeere— K A Kl_ A iTVC DIetoirash Peenee 5.60 23 Plate Vernier SS.S0 BAttfeAlNS F^wjj. ,„ •i w-jjr-Jjr. 4... FeVFRYTlAY ^rr." «... »* deneere, Bslsmsd Shaft, 4| SP-ikS. - - Bakellte Enda with knob and » Mats J.35 «'»'; _. . Trlpls Bank Weund Coll tar N. « fists 4.10 A. A. ISO ts 3000 not ere. 23 Plate 3.75 Silk wire on Bakellte Tube. .. . 2.78 Hook-up asins thla sail, whleh has breusht In Havana, (smithed seen request. MONEY ORDER OR CERTIFIED CHECK MUST ACCOMPANY ALL ORDERS SUNBEAM ELECTRIC CO. 71 THIRD AVE. (Bet 11th and 12th Sts.) NEW YORE Telephone 2890 Stuyveaant COMPLETE YOUR FILES OF RADIO WORLD FOR 1922 Back r H-rs ml Radio World are becoming scarcer all the time. We. ea k* e Iron No. 1 to data at fifteen cents a copy. Any seven RADIO WORLD, MM Broadway, New York City Just Off Press! WEBSTER'S Nww Modern ENGLISH DICTIONARY UZ2 COPYRIGHT ILLUSTRATED SELF-PRONOUNCING RADIO AND WIRELESS Tails Is til* Only Dictionary Publish*! Devoting; a Special Section to Ratio and Wireless. There are Listed and Defined about MM Words, Terms and Phrases most Cotnmonly Used in these Popular Sciences. A AhtleVnuart. H, sheet Rani . A U ttebOTatanM GsTW All Others. Bin i>/.*7Vk*t Beaad la Seal Brained Fsartkeia MF Book Paper R rised and Broiturht Right 1. P to- Data— ( ttalnins Many Special Featnras Not Found in Any Other Dictionary. AD NEW and LATE WORDS Special Prominence is Given • Dictionary of mil the New and Late Words, Incrnrlrnt those especially relating to the World War and other words in the Arts and Sciences that have lately come into our language. General Vocabulary 020 Paiea. ASaanata tar Every Ordinary Olstrsasry Need. The J00 Paae Barferenee Library In. fusee Eapeelelly Uastal Supplemental Veeaku lariat, and Refaranea TaMae al Greatest Practical Value. THE COLUMBIA PRINT 1SJ3 Broadway New York City The farmer was snowed in. Rural mail carriers found it imposible to get through for days. In some cases the telephone lines were tem- porarily out of commission. Not- withstanding his isolation the farm- er with a radio receiving set was able to get the news of the day; he kept in touch with market prices though he was not able to take ad- vantage of favorable quotations and during the evening he and his en- tire family were entertained with music and speeches. Action on White Bill Developments in radio legislation are discouraging in that no action was se- cured in the House on Wednesday when the White bill was introduced. After an afternoon of debate, chiefly due to unin- formed members who propounded ques- tions, some of which indicated that they 1 had not read the bill, the matter was de- ferred until a later date. The discussion revealed the fact that there were, how- ever, no real objectors to the legislation. No Free List Radio World has no free list. The only copies sent out by the publish- ers are to fill the ever-increasing orders of the American News Com- pany, the large numbers of subscrip- tion orders received at the office of publication, and one voucher copy to each advertiser and advertising agent represented in current issues. Radio Wowt d. 1403 Broadway. N. v Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered aa second-class matter, March 28, 1922, at the Poat Office at New York, K. Y., under the Act of March 3, 1879.] A Wr*kly Jotmial, PabUahed Erery Wednesday and Dated Saturday, by Hennesay Radio Pablicatioa* Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 47ft. Vol II, No. 21. Whole No. 47 February 17, 1923 15c per copy, $6.00 a year Canada's Largest Radio Station Broad- casts in Both French and English By Pierre D'Orsay THE most powerful broadcasting station in Canada is located in Montreal, and is operated under the direction of the French newspaper, "La Presse." One of the features of this station is that it is the only broadcasting station that possesses a pipe organ as a part of its installation. J. N. Carrier, who is announcer, manager and operator, was responsible for many of the unique features embodied in this station. They are absolutely no motor generators used in this station, the alternating current supply from the city being used, and rectified by means of large rectifying tubes. It is the only station in the world that broadcasts regu- larly in more than one language, both French and English being used. This is done because of the fact that there are within its range people that speak nothing but French, and therefore it was necessary to enable those people to under- stand what was being broadcast. For quality, modulation and distance, this station stands foremost among the stations of Canada, and a great many American amateurs have heard "CKAC." These accompanying pictures give a very good idea of the station and how it is operated. (C. Kadel and Herbert) J. N. Cartier, manager of station CKAC, working on the transmitting panel. The first large tube is an oscillator, while the two next to tt on the right hand side are rectifiers used to convert the alternating cm-rent to direct. This was done in order to eliminate the motor gen- erators. The first and second tubes underneath are the 1KW modulators, and the next small tube is a speech amplifier. While one of the most powerful of radio stations, it is said to be most simple to operate. (C. Kadel and Herbert) The magnificent pipe organ in the studio of the Canadian broadcasting station, CKAC, located at Montreal. This is claimed to be the only broadcasting station in the world that possesses a pipe organ as a part of its regular equipment, and many people have commented upon the wonderful organ recitals that are sent out by this station. The micro- phone, as can be seen in the picture. Is located directly In front of the (C. Kadel and Herbert) The microphone current control used In this station. This device was built by Mr. Cartier and is used to regulate the speech intensity and quality. It is one of the devices that make the station simple in opera- tion. Mr. Cartier, who designed it, is one of the foremost radio men in Canada, and the entire design of the station and of its apparatus was completed under his direct charge. This station has been heard over great distances. In Next Week's Radio World The Limitless Possibilities of Radio for the American Farmer, by Gen. James G. Harbord Digitized by LjOO^IC

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4 RADIO WORLD Importance of Radio Transmitter on Ships of Many Classes By B, R. Cummings A RADIO transmitter is primarily an alternator. In- stead of generating the usual commercial frequencies, however, radio transmitters generate frequencies in the order of from 20,000 to 1,000,000 or 2,000,000 cycles. Obviously the usual form of alternator cannot be employed for this purpose, and the system used is usually one which is not dependent on moving mechanical parts. The function of a radio transmitting equipment is to generate alternating current at these frequencies and trans- fer its output to the antenna system. The antenna system consisting of aerial wires, inductance units, and a ground system, or counterpoise, forms a series alternating-current circuit, which represents the load on the transmitter. Fre- quencies of this magnitude (so-called radio frequencies) are essential in order that efficient radiation of energy be obtained from the antenna. Of the total power in the antenna, the percentage that is radiated decreases very rapidly as the frequency is lowered, or (which is the same thing) as the wavelength is increased. Radio transmitters in order to be applicable for com- mercial use must usually be capable of generating any one of a number of frequencies, and in many cases must be so designed that the frequency of its output can be changed by throwing a single switch. This requirement is brought about by the fact that, in commercial traffic, it is customary to use one wavelength for calling purposes and then to transfer to a second wavelength for communication, keeping the calling wave free for calling purposes. When the transmitter is used for telephony, a modulation system is incorporated in the radio transmitter proper. For telephony this modulation or control system consists of a group of radiotrons termed modulators. The function of the modulator is to vary the amplitude of the radio-fre- quency alternating current in the antenna circuit in such a manner that the envelope of the maximum amplitudes of the radio frequency alterations reproduces the wave form of the voice. Modern radio transmitters are rated *in terms of their output in watts or kilowatts, which is in keeping with the rating of other electrical machinery. For example, when we speak of a "one kilowatt radio transmitter," we mean a transmitter which puts one kilowatt of power into the antenna system. Radio transmitters are built with outputs from as low^as one watt or less to as high as several hun- dred kilowatts. The largest single radio transmitter was built by the United States Navy Department at Bordeaux. France, and has a capacity of 1,200 kilowatts. This station, known as the Lafayette Station, call letters "LY" sends on a wavelength of approximately 23,400 meters, and can be readily heard in the United States. The proportion of the input into the antenna system which is actually radiated into space depends upon a num- ber of things, chief among which are the wavelengths at which transmission is carried, and the resistance of the antenna systern including the ground or counterpoise. It is permissible for any one to maintain and operate a radio transmittine station, providing a license is obtained from the United States Department of Commerce for such operation, and providing transmission is carried on in ac- cordance with the rules and regulations of the Department of Commerce, and in accordance with anv restriction placed upon the equipment by the manufacturers. ' In a previous paper read at the General Electric Co. station, the term "wavelength" was defined. The wave- lengths which may be used by Radio Transmitting Stations are assigned by the Department of Commerce. All wave- lengths below 600 meters are assigned to commercial work, those below 200 being assigned to so-called "amateur trans- mission." The wavelengths 360 and 400 meters have been approved by the Department of Commerce for radio Broad- casting, although these wavelengths have not as yet been established by law. All wavelengths between 600 and 1,600 meters are re- served for the exclusive use of the U. S. Government, and are used by the various Government Departments, including the Army and Navy, for radio communication between shore stations, warships of all types and aircraft. The necessity for restricting a band of wavelengths for govern- ment use, thereby insuring freedom from interference from commercial radio traffic, is, of course, obvious. Wave- lengths above 1,600 meters are available for commercial radio work. To secure a license for the operation of a radio trans- mitting station, it is necessary that the applicant be able both to send and receive the Continental Code at a rate depending upon the class of license requested, and to give assurance that he is capable of operating his own appa- ratus. The restriction that licenses are given only to people capable of receiving the Continental Code is based upon international regulations which require that all transmit- ting stations cease sending immediately and give absolute priority to any distress signals from a ship at sea. Ob- vously therefore the operator of any transmitter must be able to receive and identify such distress signals in order that he may comply with this requirement. Since 1912 it has been required by law that every ship cruising more than 200 miles from shore, and carrying 50 or more persons aboard, including the crew, be equipped with a radio transmitter and receiver capable of com- municating a specified distance. Not only must such equipment be installed on all vessels but must be inspected by an inspector of the Department of Commerce each time the vessel puts into port. If the inspector of the Depart- ment of Commerce finds that the radio equipment is not, in his opinion, capable of carrying on the required com- munication and gives indication of unreliability, he reports this condition to the commanding officer of the vessel. Any vessel which sails without remedying this condition is subject to a penalty of $5000.00 This requirement is, of course, fundamentally intended for the^ safety of the personnel aboard the vessel, and in this connection it is interesting to note that probably no other piece of electrical or other equipment is so likely to be called upon at any time to be responsible for the safety of hundreds or thousands of people, as the radio transmitter. The most difficult engineering in the building of radio transmitters is not in establishing electrical cir- suits which will function as required, but in the selection of materials, and in establishing the necessary safety fac- tors, which will insure reliable service under the extremely varving conditions of installation and operation. From all of which it can be seen that the business of the sea has been vastly affected by the new science of radio. Digitized by Google

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RADIO WORLD S An Inexpensive Reflex Receiver By C. White 9 Consulting Engineer THE REFLEX type of receiver is here to stay and this fact is clearly demonstrated by the activity that is being shown by both amateurs and manufacturers in its development. The idea of the reflex receiver is by no means new, for the French made extensive use of it during the recent World War. While the principle has been simple enough in theory, still there has been quite a bit of trouble to get the many different types of circuits simple enough for gen- eral construction and use. The trouble has been mainly in getting a reliable form of radio-frequency amplifica- tion. Although the tuned-plate type of radio-frequency am- plification possessed the desired amount of selectivity, still when more than two stages were employed it was almost next to impossible to hold or get the proper adjustment. Radio- frequency amplifying transformers have been highly developed so that it is possible now to employ as many as five stages with-little or no bother in operation since there are no controls on the transformers. For a single tube circuit, such as I shall describe in this article, the tuned-plate is quite superior in that it is not only a cheap but a thoroly reliable method. In designing the circuit shown in the accompanying illus- tration, I have kept several points in mind. First, to de- sign a set that would be simple in operation, having as small a number of controls as possible; second, to make its action selective; and, third, to avoid the use of any switchpoints or coil taps. It will be noted that there are only four controls, the two variometers, the "A" battery potentiometer, and the filament rheostat. This means not only that a small panel can be used (about 6x14 inches), but also, that there need be only four holes drilled in the panel. To those who have tried to drill and set switch- points and switch arms exactly true this feature will be greatly appreciated. The theory and operation of the outfit are just as simple as the construction. The main tuning circuit or the Ant.- Gnd. circuit consists of a fixed mica condenser C-l of .0005 mfd. capacity, and a variometer. After the incom- ing signal has been tuned in, the high-frequency waves pass on to the grid and filament, taking the path thru the fixed mica condenser C-3 instead of the secondary of the audio frequency transformer A. T. which forms a path of high impedance to high frequency oscillations. The capacity of the condenser C-3 should be about .002 mfd. for the average audio- frequency amplifying trans- former, but the amateur will do well to try out several sizes, for under some conditions satisfactory operation has been obtained with C-3 omitted completely. The vacuum tube amplifies the radio- frequency carrier wave and passes it on thru the bypass condensed C-4. which has a capacity of .001 mfd., to the tuned-plate cir- cuit element, consisting of a fixed mica condenser, .0005 mfd. (C-2), and a variometer. The crystal detector picks the voltage from across this variometer and condenser and detects or rectifies it. The rectified portion goes on to the primary of the transformer, and is reproduced amplified in the secondary. Now the audio-frequency waves pass thru the tube to be amplified and in the plate circuit the phones render them audible. The purpose of the circuit is to make one tube play the dual role of radio- and then audio-frequency amplifier. The virtues of this set do not end in simple construction and theory, but above all it is the cheapest and most inex- pensive to build as well as operate. For comparison with the itemized bill of materials of other receivers I will list Fig. I. accompanying Int. Tka coal to a mUaram. By law um of Tkua b a vary ••ally the parts necessary for the construction of the tuner. The following list does not include tube, batteries, or phones: 2 Variometers $10.00 1 Audio- frequency transformer 6.00 2 .0005 mfd. mica condensers M 1 .002 mfd. mica condenser .40 1 .001 mfd mica condenser .40 1 Vacuum tube socket ;.. 1.00 1 Filament rheostat 1.20 1 Potentiometer (250 ohms) 1.60 1 Crystal detector 1.40 1 Panel 220 Binding posts, wire, etc IjOO Total $26.00 In the foregoing estimate I have given the average cost of the various items, but the total cost should not exceed the total of $26.00 unless exceptionally expensive appara- tus is purchased. Of course, if the price of a good cabinet is to be added the total cost of the set can be approximately placed at $30.00, which is indeed very reasonable for • high grade receiver for radiophone work. The volume obtained will not be lower and most likely higher than that obtained from the best single tube regenerative outfit, while the quality will be exceptionally excellent, due to the fact that a crystal detector is used. The receiver is not intended for straight C-W work, but is paramount for radiophone reception on the wave lengths at present employed by broadcasting stations. Six New Broadcasters THE following broadcasting- licenses have been issued by the Department of Commerce: KFGB, Loewenthal Brother*. Pueblo. Colorado, 10 wttn: WQAF. San- dusky Register. Sandusky. Ohio. 5 wans, .'60 meters; VRAM. Lombard College. Galr.hurg. Illinois, 100 Mill: WpAD, Whilall Fl-rtric Co. Water, trirv. Oomir. t-.-ut. 10 »itt»; WSAB, SoutneaM Mi»»ouri State College. Cip* ri.rjrdeiu. Miivmi'i. 1'TO watts; WQAH. Brock- Anderson Electricl En- g;nferirg Co, Lexington. Kentucky, JO watts. Digitized by Google

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6 RADIO WORLD TWO- Way Talk^By Radio Birds, Song, Mystery Broadcasting Station at Rensselaer Polytechnic Institute Exchanges Verbal Communication Between WHAZ at Troy, New York, and CFCN at Calgary, Alberta, Can. TROY, N. Y., February 4.— For the first time since the discovery of wireless, two-way radio telephone verbal communica- tion more than two thousand miles overland has been accomplished. This feat was per- formed at the instance of radiophone station WHAZ, the largest college broadcasting sta- tion in the world conducted by the Rensse- laer Polytechnic Institute at Troy, N. Y. The two-way. communication was carried on with absolute success and at the will of the operators with station CFCN at Calgary, Al- berta, Canada, a distance of approximately two thousand miles airline, and breaks all previous records for two-way overland radio telephone communication by a wide margin, and it is not believed that this distance has ever been exceeded even over water. The new radio station at the Rensselaer Polytechnic Institute, although established only at the opening of the college year last fall through a gift of $50,000 from the Roeblings, engineering graduates of the in- stitute, famous as the builders of the Brook- lyn Bridge, has already become well-known as the most versatile as well as the widest in range and one of the most efficient of the Class B installations in the United States. Unlike nearly all of its companion high- power broadcasting equipments, station WH AZ does not confine itself to broadcast- ing, but enters into all other phases of wire- less activity as well. Regularly Heard Over the Continent Of course the Troy Polytechnic station, like many others, has been heard over con- siderably greater distances than that of the two-way test. In fact, station WHAZ an- nounced recently the establishment of a new world's record for long distance broadcast- ing of concert programs, clear reception of both music and speech having been reported from three communities, Hilo, Wailuku and Haiku in the Hawaiian Islands, a distance of approximately 5,500 miles. Its regular Monday evening concert programs and its monthly international midnight programs have been heard in France as well as throughout the North American continent from coast to coast and from Alaska to Panama. It is not unusual for its broad- casts to be reported heard in all of the forty-eight states of the Union, in every province of Canada, in Mexico, Cuba, Porto Rico and the Panama Canal Zone. Widely scattered instances of these reports' have come from a Northwest police officer in Hodgson, Manitoba, a snowbound prospec- tor in Alaska, a sojourner in the eternal summer of Miami, Florida, a Cuban planter, a minister entertaining his little group of parishioners high up in the mountains of Lake County, California, a rancher in Mon- tana, a government official in Mexico City and an engineer in Panama. The point is. however, that such listeners have no way of replying, except by cable, telegraph or let- ter. This has been true, heretofore, even of the high-power, long-wavelength trans- mission experiments carried on with England by the large commercial companies. Many Difficulties Overcome As all radiophone listeners know, it is one matter to "pick up" a program broadcast from a station, say two thousand miles away, by accident, and an entirely different thing to "receive" from a particular station at that distance, by design, at a definite time and regardless of all kinds of interference. Yet that is what both stations WHAZ and CFCN did early on the morning of Janu- ary 13 last. A previous test, hastily arranged and quite casually after the midnight transcontinental program from station WHAZ at Troy on the second Monday of the month, was a partial failure because of interference from other radiophones near Troy. Work was then hurried on a new super-selective re- ceiving set, which had already been almost completed by the engineering instructors at the Rensselaer Polytechnic Institute, and a more complete test was scheduled for four days later. That time, in spite of very severe local electrical disturbances, commu- nication was established during the pre-ar- ranged period and was maintained as long as desired, actually for more than an hour. The communications of the test were re- ported heard at many remote points. There was a heavy snowstorm in progress in Troy at the time and the static was extremely bad. Sparks were continually jumping across the antenna series condenser and it was possible to operate a small electro-static motor by connecting it across the antenna and ground wires. A Powerful Receiving Set The radio engineers at _ the Rensselaer Tech describe the new receiving set, which they used in this record-breaking test, as a conventional type of super-heterodyne, em- ploying a maximum of eleven vacuum tubes. Eight were used at the time of the test with Calgary. The 400 meter wave length of the incoming signal is first changed to 3,000 meters; the signal is then amplified by a five-stage radio frequency amplifier and passed on to a detector tube. Additional audio frequency amplifiers are used when it is desired to use a loud speaker. Pacific Coast stations were heard with this receiver on the night its construction was completed. Varied experiments are being carried on now by the Institute engineers with other sets of this type which are less conventional, and the Institute is providing a large amount of equipment and measuring apparatus. Short- Wave Experimentation Short-wave telegraph experiments of all kinds are being conducted by the radio staff and Station 2XAP, the chief radio telegraph installation of the Institute, has been re- ported QSA in Hawaii, France and Eng- land and at all points between. This sta- tion was one of the first successful contest- ants in the transatlantic tests last Decem- ber. A larger telegraph transmitter of a newer type is now nearing completion, and several smaller sets are in operation for short, distance work. The two operators at the Institute station state that they will be glad to use both 2XAP and 2CDC in inter- collegiate communication and in American Radio League work as much as their rather limited time permits. From all this it is apparent that the Mon- day evening concert programs, with which the radio public of the country is now so familiar, represent but a part of the wireless activities of the Rensselaer Polytechnic In- stitute's versatile radio station. ivu^ki ana Herbert) At ■ recent demonstration, three mechanical birds were made to move their head* and sins in the moat mysterious manner. The birds sane the Mendelssohn "Spring- Son*-" and moved in a very natural manner. Makes Deaf Hear (C. Keystone View Co.) Geo. Farrar, 12-year-old lad, attending the California School for the Deaf, claims ha has perfected a means of — uMl^g the deaf te hear by means of vibrations. Power amntt- fiers are used in connection wtth phonos sliieji diaphrams are unusually thin, so that the vibration against the dead ear drums are as strong as possible. Digitized by Google

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RADIO WORLD 7 The "Farthest North" Broadcasting Station By J. L. Wilkie TO amateurs, sitting in nice cozy, warm rooms, with loud speakers and all the newest accessories which make the up-to-date radio set, this ar- ticle is addressed. Imagine, if you will, that instead of being where you are, you are up in "the farthest north," where the wind is biting cold and where the snow lasts for ten months in the year instead of ten weeks. Add to all this the hardships of working under the most adverse conditions possible, and you will have a slight idea of what the crew of the "World's Farthest North Radio Broadcasting Station" has to con- tend with. This broadcasting station in ques- tion is the one located on Jan Mayen Island, a tiny cone of an extinct vol- cano, in the Arctic Ocean, • north of Iceland. This station is financed by the Norwegian Government, and is in charge of Akbard Ekerold, an Ameri- can citizen. This station was erected by Norway, as a Central Weather Broadcasting Station, because of the fact, well un- derstood by scientists, that all weather, be it good or bad, warm or cold, windy or calm, originates in the Arctic zone. This is the first of three stations that will be erected in the Arctic, and when the three are in operation, it is ex- pected that weather predictions, orig- inating from the chain of- stations, will be so accurate that storm warnings can be sent out with amazing accuracy, and many lives and millions of dollars can be saved. Imagine the captain of a large ocean liner crossing the vast expanse of water. Suddenly, the radio operator picks up the telephone that connects (C. Gilliams Service) The Ekerold party that established the station. Mr. Elkerold, who is in direct charge of this station, is the second man on the right. The man at his left Is chief operator. with the bridge. "Yes, sir. Jan Mayan Island just sent out a storm warning of a hurricane originating over latitude — — , longitude , and sweeping rapidly southeastward." The captain, plotting his course, and the course of the hurricane, finds that if he continues on the direct course he is pursuing he will cross the path of the storm in a certain number of hours. Therefore, secure in the knowledge that he possesses he is able to either change his course or make such changes as he thinks necessary for the safety of his passengers. These daring pioneers of this out- post of "radio communication" are to be commended. The service that they render to the public in general cannot be measured in terms of dollars and cents. (C. Gilliams Service) The antennae used by the world's "farthest north'' broadcasting station, established by the Norwegian Government for the purpose of broadcasting weather forecasts, marks the outpost of civilization. It is located on Jan Mayen Island, in the Arctic Ocean. (C. Gilliams Service) Transmitting apparatus used, A* travel to impossible for nearly seven months of the year, it was not thought advisable to install the regular telephone apparatus. Therefore, regular spark transmitting apparatus is Digitized by lifting apparatus is used. Google

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RADIO WORLD Radio Frequency vs: Audio Frequency Amplification By M. C. Batsel Radio Engineer, Westinghouse Electric & Manufacturing Company CONSIDERABLE confusion exists in the minds of the public regarding the functions of radio frequency and audio frequency amplifiers. In this article I shall endeavor to give the distinguishing difference between these two methods of amplification, and to point out the advantages of each. If music or speech is received by means of a detector tube only, without regeneration or other amplification, the music is not very loud, even when received from a nearby, powerful station. Distant stations, though received distinctly, may be so weak that they are heard with difficulty. When weak stations are heard distinctly, they may be made as loud as desired by using audio frequency amplification. If head phones are to be used, there is little or no advantage in using more than one stage of audio frequency amplifica- tion, as experience has shown that if the music or speech cannot be heard distinctly with one efficient stage of amplification and good head phones, they cannot be heard with any amount of audio frequency. If an efficient loud speaker is used two stages of audio frequency amplification will give about the same strength as an ordinary phonograph, provided the music can be heard distinctly on the detector tube alone, and if sufficient power can be delivered by the last amplifying tube. It is often advisable to use two tubes in parallel in the last stage of amplification unless a much higher plate voltage is pro- vided for this stage than is used for the first stage. Addi- tional stages of audio frequency amplification can be added to make the music or speech as loud as may be desired. In order to preserve the quality of music and speech, the audio frequency amplifier must be capable of amplifying practically all audible frequencies. All noises due to bat- teries and tubes are, therefore, amplified to the same extent as the music. For this reason it is necessary to use plate circuit batteries especially designed for use with vacuum tube amplifiers and to have all parts of the circuit well insulated. Audio frequency amplification is absolutely necessary for satisfactory operation of a loud speaking receiver. Since the advent of radio broadcasting much development work has been done to improve the audio frequency amplifier, and as a result amplifiers have Veen developed which pro- duce practically no distortion of music or speech, and loud speaking receivers are now available that reproduce music so accurately that it meets the approval of the most exact- ing critic. All radio detectors that can be used for the reception of music are least efficient when the received currents are weakest. For this reason radio frequency amplification is desirable. Radio frequency amplification strengthens the received currents before they are changed to audio frequency by the detector. Thus by using radio frequency amplification, stations can be heard distinctly which cannot be heard on a simple detector and with any amount of audio frequency amplification. The most widely used and simplest form of the radio frequency amplifier is the form represented by the Arm- strong regenerative circuit. This is also the most efficient means of obtaining radio frequency amplification. No additional tubes are required, the same tube being used as a radio frequency amplifier and a detector. Most all efficient radio frequency amplifiers, that operate on the wave lengths used for broadcasting, function on account of regeneration. The regenerative detector tube produces about the same amount of amplification as can be obtained by using two stages of radio frequency with transformers. If mote amplification is desired than can be had with a regenerate tube it is necessary to use at least three stages. The benefits accruing from the use of a great amount of radio frequency amplification are : it gives greater sen- sitivity ; smaller antennae or coil antenna may be used; and due to the greater sensitivity very loosely coupled antenu and secondary circuits may be used, resulting in a greater selectivity. The greatest use of multistage radio frequency amplifiers is where receivers are located in apartment houses or in other locations where an efficient antenna cannot be erected, or when extremely weak stations are to be received. The loud speaking receiver with three stages of radio frequency amplification usually has at least six vacuum tubes. Tbt expense of maintaining the tubes and batteries is, of course, greater in proportion to the number of tubes used. During the summer months there is a greater freedom from atmospheric disturbances when small antenna or coils are used with the radio frequency amplification. This is due to the fact that the small antenna is less affected by atmospheric disturbances, than is the large antenna, in proportion to the energy received from the transmitting station. The development of tubes requiring a small amount of filament energy and operating on dry cells should give a considerable impetus to the development of multistage radio frequency amplifiers. The elimination of the storage battery as a necessary part of the receiving equipment makes it possible for those who desire to operate a radio receiver in a well furnished room, to do so without danger of injuring the floor coverings and woodwork. The entire equipment using dry cells may be enclosed in an attractive cabinet and requires no attention except an occasional renewal of dry cells. These can be purchased at any electrical supply house. Gov. Alfred E. Smith's Noon Hour Address Broadcast Governor Alfred E. Smith of New York, who appeared before a special noon honr meeting of the New York Board <-•'' and Transportation on Saturday, Feb. 3, outlined his plans and policies toward the big problems that con- front him in his second administration. Governor Smith's address was broadcast direct from the clubrooms of the New York Board of Trade and Transportation at 41 Park Row, New York City, on a 360 meter wave length by WJZ. The broadcasting of this address made it possible for business men in New York State to get the Governor's viewpoint ii the same time or perhaps a fraction of • second before the gathering at the dak- rooms. Sound waves travel by radio o«f a million times faster than they travd through the air ; namely, 186,000 miles • second by radio and only a thousand feet a second through the air. Digitized by Google

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RADIO WORLD 9 Efficient Radio Control of Battleships ONE of the latest inventions tried out recently by the United States Navy is the control of a battleship by means of radio from an airplane above By Garrett F. Erskine fact, everything that is possible with a full crew of men was attempted and successfully carried out. Of course, the principle of radio con- ic NEW* b«CDUJ Mho of U-tech |nt bain* fired by imhi at •hip. Tula Is oae of the latest laiwtkH bU eat by the United States and I* ■ perfect nm> — also from another battleship miles distant The apparatus installed con- trolled the speed of the vessel, steering it at the will of the operator on the remote vessel, .fired the guns ; and, in trol has been known of for several years, and many small models of both ships and automobiles have been successfully built and worked; but this is the first time that radio control has ever been attempted on such a tre- mendous scale. While the maneuver- ing of the ship was in the hands of the operator in the airplane or on the distant ship, there were still enough men aboard the radio-controlled •hip to enable the men to take the ship back safely in case any trouble was experi- enced with the control apparatus. In this maneuvering of die ship a special wave-length was used to pre- vent any trouble being caused by in- terference. The mechanical details, such as the loading of the guns and die starting of the fires in the boilers, were, of course, impossible by remote control, and were done by the gunners and fire- men aboard the ship; but the actual firing of the guns and steering of the ship was independent of the few men aboard. The United States Government is the first to successfully utilize radio as a means of controlling vessels, and, although many other governments have been attempting it, we are the first to really do it successfully. This, of course, will be of the utmost impor- tance in case of any future trouble necessitating the use of men and battle- ships. It will mean a great saving of life in case of war, and will also mean that the immense number of men that have heretofore been a necessary part of a ship's complement will be reduced as all die necessary maneuvers can be executed from an airplane above. CoL E. H. R. Green an Ardent Radio Fan Ha (C. Fototrami. N. Y.) Oil— I Edward H. R. Green, aulionalre n of the late Hatty Green, la a radio fen of the first water. Ubaratoriea la the United States, and etane el the aeoet eeaaaeat redto experts In the world are baa (teen ewer to tba purpose of bnproTine; radio. CoL Creea is aa ardant tsperfanealer blaex laboratory, aad tba radiophone station at Round Hula, Mesa, baa been beard at area! dtataacee. Tba abate sbows one with CoL Creen in tba canter riant-bud tide spending a pbaaant law easeaoats of the of the Digitized by Google

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10 RADIO WORLD Latest List of Broadcasters Totals 570 By Carl H. Butman WASHINGTON, D. C— For the first time since broadcasting began in September, 1921, fewer new stations were licensed during the past month than dropped out, indicating that the field for broadcasting is practically filled. This is not to be wondered at, officials point out, because the "saturation point" has been reached. Many fans say, "Well, there are enough anyway ; we don't want any more ; let the better ones survive." Today there are 570 broadcasting stations, 28 of which are in the B Class on 400 meters, the balance being on the more popular 360 meter wave. On January 1 there were 576, showing a loss of six during the month. While there were 28 new stations licensed in January, 34 old ones failed to renew their licenses. On the first of February last year, there were only 36 stations licensed in the new pastime of broadcasting — today there are almost 16 times mat number. Many peo- ple believe that this is far too many, particularly since they are not well distributed on the 360 meter wave. The radio bill, however, provides for the distribution of a large num- ber of new waves, which will aid in decreasing the inter- ference. Competition is creeping into the game. The best equipped stations giving the best service to the fans will probably become the permanent ones in the long run, it is believed. Within the past week, seven new broadcasters were licensed by Mr. Hoover's Radio Section, and two Class A stations were transferred to the B Class, on the 400 meter wave. List of New Broadcasting Stations WRAV— Antioch College, Yellow Spring, Ohio, 200 WQAO— Calvary Baptist Church, New York, N. Y„ 100 wstts WPAZ— Koch, Dr. John R, Charleston, W. Va., 20 watts. KFCV— Mahaffey, Jr., Fred, Houston, Texas, 50 watts. WRAJ— Pickering Co., M. H., Pittsburgh, Pa., 500 watts. WQAR— Press Publishing Co., Munde, Indiana, 10 watts. WSAA— Sprague, B. S. Elect. Co., Marietta, Ohio, 25 watts. Transferred from Class A to Class B Stations on 400 Meters KFI — Anthony, Earle G, Inc., Los Angeles, Calif., 500 watts. KPO — Hale Bros., Inc., San Francisco, Calif., 500 watts. Broadcasters Which Hare Stopped The thirty-four broadcasters which have not renewed licenses and consequently were deleted from the records of the Commerce Department during January follow: Broadcasting Stations Deleted WLAO — Anthracite Radio Shop, Scranton, Pa. KZY — Atlantic-Pacific Radio Supply Co., San Fran- cisco, Calif. WNAJ — Benson Co., Chicago, 111. KFBN— Borch Radio Corp., Oakland, Calif. WOE — Buckeye Radio Service Co., Akron, Ohio. KDYO — Carlson & Simpson, San Diego, Calif. WPE— Central Radio Co.. Inc.. Kansas City, Mo. (Re- licensed at Independence, Mo., Jan. 5th.) KFBM — Cook & Foster, Astoria, Oregon. WSX— Erie Radio Co., Erie, Pa. KDZW — Gerdes, Claude W., San Francisco, Calif. KFAC — Glendale Daily Press, Glendale, Calif. WDAQ— Hartman-Riker Electric & Machine Co., Brownsville, Pa. WKAZ — Landau's Music & Jewelry Co., Wilkes-Barre, Pa. WKAD — LoofF, Charles, East Providence, R. I. WBAJ— Marshall-Gerkin Co., Toledo, Ohio. KVQ— McClatchy, James, Sacramento, Calif. WDAV — Muskogee Daily Phoenix, Muskogee, Okla. KDZP — Newbery Elect Corp., Los Angeles, Calif. KFC— Northern Radio & Elect. Co., Seattle, Wash. WBAB— Potter, Andrew J., Syracuse, N. Y. WAAX — Radio Service Corp., Crafton, Pa. KYY — Radio Telephone Shop, San Francisco, Calif. WNAG — Rathert Radio & Elect. Co., Cresco, Iowa. WGAS — Ray-Di-Co. Organization, Chicago, 111. WFO— Rike Kumler Co., The, Dayton, Ohio. WPJ— St. Joseph College, Phila., Pa. KFBCj — Savage Elect Co., Prescott, Arizona. WHW— Seeley, Stuart W., East Lansing, Mich. WSN — Ship Owners Radio Service, Inc., Norfolk, Va. KJC — Standard Radio Co., Los Angeles, Calif. WCAQ— Tri-State Radio Mfg. & Supply Co., Defiance, Ohio. WJAL— Victor Radio Corp., Portland, Me. WNAH— Wilkes-Barre Radio Repair Shop, Wilkes- Barre, Pa. WJAU— Yankton College, Yankton, S. D. First American Aircraft ^ Licenses Issued By Washington R. Service WASHINGTON, D. C— Radio as a safety measure for the protection of pilots and passengers has come into its own in air travel as well as on die sea, where its value was first realized. Seven airplanes and flying boats are now equipped with radio and answer to regular calls. The first American aircraft, other than those of the Army and Navy, which are all radio-equipped but not licensed, to be licensed as a limited commercial station was one belonging to the Airline Transportation Co. of Cali- fornia. Aircraft Licensed as Limited Commercial Stations on 525 Meters KFBI — Airline Arrow, No. 1, Airline Transportation Co., Los Angeles, Calif., Aug., 1922. KFBY — Balboa, Aeromarine Airways, Inc., New York City, Jan. 18, 1923. KFBA — Buckeye, Aeromarine Airways, Inc., New York, Dec. 22, 1922. KFBF — Gov. Cordeaux, Aeromarine Airways, Inc., New York City, Jan. 18, 1923. KFBJ — Nina, Aeromarine Airways, Inc., New York City, Jan. 18, 1923. KFBM — Ponce de Leon, Aeromarine Airways, Inc., New York Gty, Jan. 18, 1923. KFBZ — Santa Marie, Aeromarine Airways, Inc., New York City, Jan, 18, 1923. Digitized by Google

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RADIO WORLD 11 A Hookup That's a Wonder By George W . May ONE of the old-time devices used for tuning was the tuning coil having one, two or three sliders. Many are in use since the idea of broadcasting swept the country, probably because they can be constructed quickly A new sinf le-circuit, one-tuba set that wiH keep the experimenters busy for a while. The grid leak In this aet Is very critical Br the use of the honeycomb cou, any wave length may be reached. When short waves are de- sired, the variometer alone is used. Extreme care should be taken in the wiring of tins est. and easily, but their efficiency is not to be compared to the results obtained with variometers, or honeycomb coils. Several new hookups have appeared from time to time, but there is shown herewith a hookup that is the "cat's meow" when it comes to breaking in on DX stuff. You don't have to throw everything you have into the paper bag or into the furnace, but just make a list of its parts and look over the ones needed. The parts consist of a vario- meter, a 22-volt B battery, 43 plate variable condenser, vernier type, a grid condenser and leak, a vacuum tube and its etc., and also a honeycomb coil with switch. The leak in this hookup is a very critical part of the sketch and most careful attention should be given the tube. Also it permits the amateur, with the use of the honeycomb, to get up on the higher waves and listen to the trans- oceanic stations as well as the shorter ones. It utilizes a simple circuit by carrying a wire back from the plate to the antenna lead so that a honeycomb coil can be used with the variometer. Radio World of Nov. 25 showed the original May circuit — a diagram similar to this. Under ordinary circumstances this would constitute a tickler cob, but in the present case it is only in the apparatus. The tuner takes in all wave lengths from the amateur to transatlantic by merely shifting coils. It is simple to assemble and admirably serves the purpose of the radio- phone novice. For the beginner or the amateur getting out of the crystal class it is, in my opinion, "the goods." Never mind the mounting of the parts of the panel. Just take a brief glance at the diagram and proceed to the makeup. A set of coils covering the desired range should include D.L. 75 up to 1500 inclusive. Using this set and hookup without any coils gives you a range within the broadcast limit. With a D.L. 1500 coil most of the high-powered stations such as POZ, FL, YN, MUU and IDO could be read with ease. Very little dif- ficulty is experienced with the set in tuning or oscillating. The beginner should make a study of the circuit and proceed easily until he masters it, and he will find that after while he will start to add a two stage amplifier for volume or louder signals. A Literary Critic for Broadcasting ALL over the country, KDKA, the radio telephone broadcasting station of the Westinghouse Electric and Manufacturing Company is recognized as having about the best trained announcers of any broadcasting station. The reason for KDKA's reputation, which is deserved, is because that each announcer is trained carefully preceding each program. A supervisor who acts as a literary critic listens to the reading of each announcement prior to its being broadcasted and corrects any inaccuracies or grammatical errors that may be found. This voice culture is an important part of the broadcasting plan. Each announcer is chosen because of the quality of his voice, for each broadcasting station is known through its announcers. Since KDKA was first started three years ago, this constant supervision has been ex- ercised over the men who tell the radio fans what is being done. At East Pittsburgh is located T. H. Bailey Whipple, Literary Critic of the Publicity Department, who exercises a constant sup- ervision over all those who speak from KDKA, in the broadcasting studio. This supervision has been the cause of KDKA receiving a great deal of praise for its "voice." Each day any number of letters are received which state that KDKA was heard best at any station because of its good voice. Part of this praise is due to the radio engineers and part of it to the quality of the announcer's voice. It has been a long time since any error has been broadcasted from the Westing- house station. Theoretically, there is no reason why any mistakes at all should be sent out, but as it is impossible to read proof on a man's voice, as can be done with print, errors do sometimes occur. It is astonishing to find how quickly er- rors are caught and how many people write in about them. It is, of course, entirely possible, that in an audience of several hun- dred thousands, there are many literary critics, but it seems the radio fan is more critical than any other class of people. An instance of what a broadcast error will stir up happened many months ago at KDKA. A new announcer, who had been rushed into the breach to fill an unexpected vacancy, unconsciously mispronounced the name of an Italian composer. His slip was slight and hardly noticeable, but within the next few days letters from all parts of the Union, including those from musical circles, college professors, and other widely diverg- ent paths were received, all calling atten- tion to the fact that KDKA had been in error. Since that experience, which was painful to the pride of the radio officials, very, very few errors have been allowed to go un- • noticed, and the announcer who makes an error always corrects himself immediately or knows that he will hear about it from those "higher up." It is only by constant supervision and training that a broadcast program can be made perfect, and it is felt that KDKA has set an example for other stations that will tend to make the average broadcasting in- tellectually higher, and what every critic wants — grammatically correct and elocution- ally perfect Youmer Jibbs: "Have you got Davenport yet?" Fibbs: "No, we decided to get twin beds instead." Subscribe for Radio World, $6.00 a year, $3.00 six months, $1.50 three1 months. Digitized by Google

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12 RADIO WORLD The Radio Primer A Weekly A. B. C. of Radio for the Beginner, in which Elementary Facts and Principles Are Fully and Tersely Explained and all Words and Terms Used by Amateurs and Experts Defined TT? HAT is the purpose of the radio yy compass? By means of the radio compass (direction finder) a person is enabled to determine the location of a trans- mitting station. In locating stations generally two or three sets are employed, usually some distance apart. By plotting the direction of each of the received signals on a m&p or chart the exact location of the transmitter can be found. * * * Upon what principle does this apparatus operate? A radio compass, or direction finder, operates upon the principle that, when a coil is turned so that the plane of its windings is perpendicular to, the direction of an emitted electric wave, the induced E. M. F. is at a minimum; but when the coil is turned so that the plane of its windings is parallel to the direction in which the waves are travel- ing the lines of force cutting the coil will be at a maximum, and the signals will be the strongest. In the operation of such a coil (loop antenna) used for direction finding there is what is termed a broad "maximum." By that is meant that there is not a critical position in the rotation of the coil at which the signal intensity in the re- ceiver will be of such intensity as to be readily distinguishable from other signals originating within a number of degrees on either side of it. This is overcome, however, by rotating the coil so that the plane of it is at right angles to the incoming signals. When this is done a sharp "minimum" signal will be heard, and more accurate bear- ings may be determined. * * * What are some of the advantages of using a loop antenna for receiving sets? By use of the principle above out- lined it is seen that loop antenna lessens interference by providing a directional effect. It is therefore easier to tune out stations that are not desired. Static or atmospheric dis- turbance is lessened. Inductances are unnecessary, the tuning generally being accomplished by means of a variable condenser in parallel with the loop and changing the plane of the loop in rela- tion to the direction of the signals. * * * Can an outside antenna be said to be directional? It is a generally accepted fact that a straight-wire antenna is more or less directional in the direction of its plane. By this is meant that, if the antenna lies east and west, the signals will be slightly stronger from either the east or west than from the north or south. This slightly different intensity, how- ever, is not noticeable, as the difference is so slight that it matters little.. * * * Which antenna is considered to be best for general use? A one-wire aerial from 60 to 100 feet in length and 40 to 70 feet in height is generally considered to be most efficient for average use. * * * In erecting an antenna, what precau- tions are necessary? When erecting an antenna it should not be allowed to touch any walls or iron structure. It should be well in- sulated. It should not cross any power lines. It should not be too long, other- wise trouble will be experienced when short-wave reception is desired. The lead-in should be brought in to the set through an insulating bushing. If more than one wire is used in an antenna the diameter of the lead-in should be approximately the combined diameters of the number of wires used. * * * What is the purpose of a "ground switch"? The purpose of . a ground switch is to connect the antenna directly to the ground when it is not in use. Accord- ing to the new regulation of the Board of Fire Underwriters they are not necessary if^ a device called the Vacuum Lightning Arrester is used. An Accidental Discovery By D. P. Metzgar AFTER spending considerable time in experimental work, and building all of the popular circuits and a few of my own, I had one of the most puzzling things happen with my outfit that I have ever experienced. One day I wanted to get a local con- cert, and not having a suitable circuit at hand, I built the well known vario- How the amplifier* #ai mounted. meter circuit. Completing this, I placed it in my cabinet. I am- using a well known two-step am- plifier which is enclosed in a steel, oval- shaped cabinet. I mounted the two-step in the center on the lid of the cabinet and proceeded to replace battery and phone connections. I placed in the grid, a .0005 condenser without a grid leak. After a moment of tuning, I knew that something was wrong. I went over the circuit -three times and found things in perfect order. In one last effort I lighted my tubes, but got no results. I started to raise the lid of my cabinet and immediately "The Star Telegram" came in loud and clear, and within the course of an hour I had copied nine phone stations, including WSB, the Atlanta Journal. I found that tuning with variometers and with secondary had no effect what- ever on the music while I had the lid open at different angles. Most of you radio fans will know that the induction from the two-step through the lid of the cabinet was the cause of this, yet how many of you can take this little incident and work out a simplified tuning device that may aid the coming radio? Tuned by raising and lowering top. Digitized by Google

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RADIO WORLD 13 WJZ Heard from Coast to Coast ' By John Kent THE map of WJZ's distance record shows the range of one of the largest eastern broadcasting stations. It is what you would see were you to visit station WJZ, the Westinghouse broadcasting station at Newark, New Jersey. By this method, originated by the operators at the station, when they receive a letter or a telegram from some locality hitherto unheard from, they place a colored pin in the city mentioned. This gives them a ready reference as to where they have been heard. In all the operators have charted over 188 towns, the furthest west being located in California and Oregon. Fifty reports have been received from England and a number from France, telling of entire programs received, and one ship at sea has heard this station on a crystal detector using two steps of audio frequency amplification while 1,750 miles out of New York harbor. This station receives so much mail during the day, that were it to announce the names of letters received over the "air" they would not have any time for the rest of their program, and so they just stick a pin in the map and ac- knowledge the letter otherwise. This was impressed on the writer on his visit to this station. An enormous pile of mail, from all parts of the continent, and some from foreign countries, was in stacks in a large table, and being read by two girls. It looked like the mail room of a mail order house instead of a broadcasting station, and vividly im- pressed on our mind the enormous range of this most powerful station. Has it'Ever Happened to You? YOUR Set is working fine — in other words, "it's the cats!" Your door-bell rings, and your next door neighbor steps in. "I just thought I would invite myself over to hear the set that you have been bragging so much about." "Sure; step right in. Chicago is just on with some fine dance music." You go into the room, light up your tubes, adjust your phones comfortably, and start tuning. Nothing happens (it never does) and you start to pet worried. "Oh, may be he has just shut down for a little while." "Oh, well, I see where they have Senator Glabbout talking at Newark tonight. Can you reach him?" "Can I reach Newark ! Don't make me laugh. It comes in so loud that you can't wear your phones — wait, here is somclxxly. Hear that squealing noise?" "Yes. who is it?" "Well, I don't know; wait until he talks." A very faint and weak voice announces. "Senator Glabbout. will now entertain the radio audience with a very interesting talk on 'My Travels Through Wash- ington in a Flivver.' " "I thought that he was talking at Newark, tonight?" "Yes. something must be wrong. It never acted this way before." And then you wonder what your friend thinks of you. Digitized by Google

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14 RADIO WORLD Transmission via Westinghouse By D. G. Littlt Radio Engineer, Westinghouse Electric and Manufacturing Company SOME very interesting things have been discovered about radio transmis- sion since broadcasting began. The pur- pose of this talk is to tell you something about the peculiarities of radio transmission, something about the difficulties encountered, and something of the development that is under way to overcome these difficulties. Consider for a moment some of our dis- tance records: KDKA has been heard on board a ship in the Pacific Ocean a distance of over 5,000 miles from Pittsburgh; also in Chile, South America, a distance of 4,000 miles. Our Newark station "WJZ" is being heard almost nightly in England and France and has been heard on board a ship in the Mediterranean, 200 miles east of Gibraltar. There seems to be almost no limit to the distances the radio waves travel under exceptionally good atmospheric radio conditions — the average range of these sta- tions is of course not nearly so great as that mentioned. We are in the habit of thinking that radio signals travel incredibly fast, with the speed of light, at approximately 186,000 miles per second. Of course this is fast compared with our fastest automobiles and airplanes, but it is nevertheless a perfectly definite rate of speed. Let us figure out the length of time it took that artist's voice w ieach the listener in the Pacific Ocean. 5,000 miles away. The artist probably stood two feet from the microphone in KDKA's studio. It required two-thousands of a sec- ond for the sound wave from the artist's mouth to reach the microphone. Another two-thousandths of a second elapsed while this sound was being turned into electrical vibrations and then placed upon the trans- mitting antenna. The 5,000 miles was then traveled in twenty-seven thousandths of a second. Another one-thousandth of a sec- ond might be required for the electrical vibration to be turned back into sound at the receiver ; giving a total elapsed time of thirty-two thousandths of a second. Now since we do not readily think in thousandths of a second this, to use an old familiar illus- tration of the speed of sound, would be the length of time required to hear the stroke of a hammer if you were standing thirty- five feet away. One might think offhand that the radio waves originating at the broadcasting station would travel outward with an equal strength in all directions, and that' at a certain dis- tance a receiving set would give a signal of whether the receiver was north, south, east or west of the transmitter. One might also think that this signal would be constant in strength whether the season were summer or winter, daylight or dark. The broad- casting listener is learning that this is far from being the case. Distant signals are much stronger in the winter than in sum- mer. Signals are received much louder at night than in the daytime. As to the direc- tion from the transmitter, each broadcasting station seems to cover certain localities much better than others. Take for example reception in Boston from Station WBZ at Springfield, Mass, 100 miles distant; from WJZ at Newark, 250 miles distant; and from KDKA at Pitts- burgh, 550 miles away. On the average KDKA is received better in Boston than either WBZ or WJZ; although it is over twice as far away and in the same general direction. Likewise KQKA is received better at Springfield than in Newark. On the other hand the States of Ohio, Indiana and Michigan seem to receive Newark better than KDKA, although Newark is twice the distance. In other words, the area covered by each broadcasting station has some dead spots where this station is received but poorly, and likewise some local- ities where reception is very good. In addition to the effects just described there are variations in signal strength from night to night which seem to sweep over the country like a cloud. In a certain local- ity for example, eastern stations may be re- ceived well, and western stations will be weak on a certain night, while the next night the reverse may be the case. On a third night, however, both eastern and western stations are loud. This then would be con- sidered an exceptionally good night for radio. Then there is fading, a name which has been applied to rather rapid changes in signal strength. This effect is noticeable only with stations over 100 miles away. A distant station may be loud for a few sec- onds and then may die down or be lost al- together for a relatively short space of time. Fading, no doubt, has been noticed by a large number of broadcasting listeners when trying to hear distant stations. To say the least it is rather annoying. Dead spots are generally constant; seasonal variations can be expected, but good and bad nights and fading cannot as yet be predicted. Observa- tions have been made by the United States Bureau of Standards on this fading with- out anything being proved except that this effect seems to follow no definite laws nor be caused by any particular condition of weather. Broadcasting difficulties due to the above conditions are more or less beyond the power of the radio engineers to "correct. Of course as a general remedy, more power may be used at the broadcasting station, but this may cause trouble due to interference, par- ticularly in congested areas where there are a numoer of broadcasting stations. The maximum output is now designated by law as 1,000 watts. The quality of transmission must be im- proved to the point where the speaker's voice becomes again a reality at the receiver. Extraneous noises must be kept out of the radio transmitter so that they will not in- terfere with the speaker's voice. The wave length of the broadcasting station must be kept constant so that the listener may be able to adjust his tuner dial always to the same point to hear a certain station. Before any improvement in this direction may be noticed however the Government will be obliged to limit the number of stations in use at one 'time in a given locality, and assign separate wave lengths to those sta- tions that operate at the same time. You may be interested in some of the precautions taken at Westinghouse stations to insure that grains are not interrupted through failure of apparatus. The most vital part of the broadcasting set is the vacuum tubes which generate the radio fre- quency carrier wave, and modulate this wave according to the voice frequency. These tubes are exactly similar to the small tubes in your receiving set, except that they are many times larger. Every Westinghouse station carries a complete spare set of nine of these tubes for replacement in case of failure of one or more of those in use. Each station also carries spares of such parts as condensers, inductances, etc., which may fail in time. In addition a large stock of tubes and parts is carried at the East Pittsburgh works ready for immediate shipment to any station. The studio equipment at Westinghouse station is installed in duplicate, that is, there are two sets of entirely separate sound pick-up and amplifying apparatus. Either set may be used, leaving the other set al- ways in reserve. It is absolutely essential that we keep on improving or else the listening public will say we are slipping backward. Experi- mental work is constantly going on at the East Pittsburgh works towards perfecting each part of the rather complex system. With proper government regulation and the co-operation of all broadcasting stations with the listening public radio broadcasting will become the service that it should be. Electrical Experts Hear First Transatlantic Phone Message (C. International New* Photo*) The foranoet electrical experts at the United Kingdom Batoning in on the ft rat wtoale** telephone message transmitted between England and the United State* by the American id Telegraph Co. Slgnor Marconi can be Men aeated in the middk of the Digitized by Google

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RADIO WOR.LD 15 Radio Transforms Life for the Lighthouse Keeper and Lightship By Albert J. Fieldson IT is fairly well agreed that where men are called upon to perform rigorous and exacting service there should be some meant provided for healthy and needed reaction. The Lighthouse Service solved one prob- lem by giving the light-tenders along the coast a very liberal amount of shore leave. Until the radiophone came along, however, it could not solve the problem of occasional diversion while the lonely sentinels of the deep were on duty. Now that the radio- phone is here with its myriad attractions, the Lighthouse Service has lost no time in bring- ing it into play, not only for intercommuni- cation between lighthouses and lightships, but also for the entertainment of the man or men on duty. With this latest addition to their already powerful apparatus, the big lighthouses and lightvessels will have as comprehensive an array of instruments as any station ashore. The Fire Island Lightship outside of New York, for example, has a complete telegraph and telephone transmitter, and an up-to-datje regenerative receiver with amplifying unit complete. It has also a radio beacon de- vice, with which it can throw radio waves in one direction much in the same manner as the lamp on its foremast throws out rays of light. All lightships, however, are not so well equipped as the one guarding the approach to the busiest harbor in the world. To some lightships, the radiophone will come as a boon, and will be the first radio apparatus of any kind to come on board. Think of those lonely old ex-mariners sitting in won- (C Kadel and Herbert) Preparing tha loop aortal on tfaa sal Lightship, used I (C. Kadel and Herbert) The Ambrose Lightship, which haa Juat been equipped with the latest radio apparatus to aid ships at sea. It has a complete direction-finding equipment, as well as tha moat up-to-date re- This lightship guards one of the channels of Now York's derment before a radio outfit, and you have one of the most interesting pictures the science can give. The almost continuous concerts coming from broadcasting stations in New York or its vicinity have made life something more than the undying sense of duty so marked in these men. Not only the lighthouses and lightvessels offshore need the radiophone. It often happens that stations situated within sight of land are cut off from the shore for months at a time, while the winter's wind howls and the stormy seas rage. Even the government tenders are unable to reach the near-by station with provisions and other supplies. During these long periods of en- forced isolation, the keeper needs a cheering word now and then, and there is no better way to give it to him than by way of the radiophone. Rather early in the history of radio com- munication, the value of wireless on board lightvessels was demonstrated by two trial outfits placed on board two lightships in the English Channel. At that time, radio was good for short distances only, thirty-six miles then standing as the record distance. This was in 1898, while Marconi was carry- ing on his now famous experiments before the Post Office officials in Great Britain. The set at East Goodwin Lightship has not been installed more than sixty days when a heavy sea struck the lightship and tore part of her bulwarks away. The mishap, the first ever to be reported by wireless, was repaired in record time. This was in Jan- uary, 1899, and as if the incident were not enough fully to demonstrate die value of the radio equipment, the East Goodwin had the misfortune to be run down by the S.S. R. F. Matthews on March 3, of the same year. This accident, seriously endangering the lives of the crew, was reported by wire- less to the South Foreland Lightship, and lifeboats were promptly dispatched to the rescue. In the interval, the other radio set, which had been placed on South Foreland, had not been idle. She had sustained no accidents, but the first message to go across the Straits of Dover was sent from that station, and received in France at Chalet d'Artois, Wimereaux, near Boulogne. It sounds in- significant in the light of present day prog- ress but at that time the spanning of the channel was considered a feat Although the distance was not greater than the thirty-six mile record, yet it was the connecting of France and England without visible wires and the wonder of the day. (C. Kauel and Herbert) First Officer G. H. Peters operating tha dbwc- tioo-finduur loop on the Ambrose. The racafrrmg set consists of detector and six stages of audio frequency amplification, as seen In tha right rear. Digitized by Google

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16 RADIO WORLD Topical Radio PI Caught tor Radio World Re Captions by Robert L. Doughert William J. Bums, haul of the Department of Justice, un tha Secret Service in tha snprenanaion of fugitrrei. Tat i be noted, la one of wall-known mnke. Mr. Ban*, awn U a firm balievar in tba Uaa that radio will make tat an ,1b tha United Statu almost an Impooaihfltty. He Danrt n record (C. Underwood ft Underwood) Receiving •tation of tha WeaUrn Electric Co., SouthgaU, London, which received the fir»t official radiophone message from New York to London. The loop antenna shown in the photo was the only one used in this work, and remarkable reception was reported. J. I. Catty, vice-president of the American Telephone ft Telegraph Co., wri the first man to enjoy the distinction of talking direct to London by tha agency of a radiophone using low wave length. In order to make absolutely sura of good reception, both radio frequency amplification and audio frequency power amplifiers wars used. While this is not the first time that radiophone has been used to span the Atlantic, it is the first time that radiophone speech has bean heard over such distances on low wave length, using a loop antenna for receiving. (C Undent Spark trans' touch wit' of the - & Underwood) the police stations of the City of New York in • pw>w udws a squad of men being instructed in the use These men will be later detailed as regular operators In tha arioua stations throughout the city. Hich will be used to keep The photograph sho (C. Photonrws, N. Y.) i u r new i ys uivwau This Is the first installation of a transmitter of tins typ* " powerful in use at the preeent time, having a relish* iW on tha loft is the oscillator, and the two smaller nan a Wireless Operator L. H. TampUn, of the S. S. Berespri mitter. By means of this new installation It Is peausW « - hBd durtaf 1st uigmzea Dy

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RADIO WORLD ] <C. International Newsred Photo*) Constable Woodin, of the MM- ropoUtaa Police of Loo dm (up- per right hua), who is a reg- ular "bobeie," and the eat ha constructed. It'a a "regular eef CeamtaMe Woodbs waa one at the Ant to report Aw lean olgnala heard la Aa wiH ba noticed. ■ quoncy amplification ia ata nahrast, Constable Woodin conatrncted tba aat ka his off i hours, aad *rith the exception of tba ruble and arnpfifrmg barm, it waa boot entirety by himself. Aa dam la In ham' dUfer- betwaea New York M order to bear a program broadcaat at New York at t o'clock P. at. he would bare to etay up until I Id, wb) • for a which ia NHe Owi. aa the tog at of tba ata-. IIl b • *e S. S. Beraagarta. £■ it to aa» of tba moat * ariUa. The largo tube aaadulatora. Cbial Mp. ~* " T fC. WMe WorM Photo) A aceae froaa "The Travolmg Saleeaaan" aa H waa broadcaat by the pmyere at tba Caaeral Electric Compaay'a autlaa at irhoas ready. N. Y. Tale particular aceae la laid ha a leal railroad station aad tbia accauata for tba telegraph matruasent abowa hi tba pbotograph Ta keep check oa bow tba program to hi lag broadcaat. tba director to equipped wftb a peer of padded phones and ia tbia way ba to abb to bear tba play aa It la being broadcaat. <(\ Wide World Photoe) ular ia the Far East, aa abowa fat the accoaapanying iOuatratloa oa tba right. Viscount ShJbusawa recently broadcaat tba addraaa which be made fat Hiblya Park. TokJo, aa tba ti nilia af tba fourth aaniveraary of the cele- bration, of the Armistice. The fact that radio baa taken ouch a tremendous bold on al the civilized countries of the world abowa the Important pool thus It nong tba moat aaa- ful

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18 RADIO WORLD Radio and the Woman ' By Crystal D. Tector j\ FRIEND of mine has written a letter to me and she claims that she has at last solved the problem of assuring herself that everyone that she invites will attend. She writes: "I simply put 'Radio Party and Tea' on the bottom of the card, and then I know that every single soul of them will be there on time. I have never had one person disappoint me, and occasionally the invited guest brings along 'a very good friend of mine.*" Well, what are we going to do when every one of us has a set? Then we will have to find some other way of enticing all the young men and "debs" to attend "our teas." * * * LAST week, after reading the radio programs for the eve- ning, we decided that we would listen to a speech by William A. Brady, that eminent producer of Broadway plays, and accord- ingly tuned in for Newark. Imagine our surprise when we were told that it was impossible for William A. Brady, Senior, to be present, but that his son, Wm. Jr., would come to his father's rescue. He gave a very interesting speech on conditions in the American theatre, and as F. H. said later, "He must be a chip off the old block," but I think that the proverb "Like father like son" more aptly fits the case. * * * A FEW of the girl* interested in radio, in my town, decided to take a trip through one of the large factories now making radio apparatus. Of course, they left all the details to me, so I wrote a letter to the president of one of the large eastern manu- facturers and received a very courteous reply, in which he said that at any time we felt so inclined, we should have no hesitancy about coming "right in." We did go "right in," and I really have not recovered yet. I never, never thought that the radio business was carried on in such a tremendous scale. I couldn't even start ex- plaining it, because I' don't know where to begin. All I can say is this one thing: by the number of girls working, winding coils, varnishing coils, soldering, etc., I think that there are more women radio experts than men. * * * WE (meaning F. H. and myself) attended a neighborhood "radio dance" given by a well meaning radio enthusiast, the other evening. Instead of dancing to radio music, we had to be content to listen to a phonograph. The main reason being that the program for that evening was made up mostly of vocal selec- tions and classical music. I never met such an apologetic man in my life. If he apologized once he apologized a dozen times I know that I listened to about ten of them. "I believe that if he could have had a 'real good cry' that he would have felt much better, sarcastically remarked F. H. on the way home. * * * A VERY dear friend of mine, very well acquainted with a girl who is a school chum of a young woman that occasionally sings at little formal teas and gatherings, stopped me on the street the other afternoon, all excited, and in a voice that just shook with emotion, said: "Gene is going to sing at broadcasting sta- tion. Don't you think that terrible ! Why, she is lowering herself to the level of a common performer." Well, I never 1 "Lowering" indeed, I think that she is indeed honored to be allowed to have the hundreds of thousands of radio enthusiasts hear her voice I notice that the stations never lack entertainers of the very highest type, even going so far as to dip into the ultra-exclusive operatic circles. * * * I RECENTLY found oat that if while I am wearing the "ear * muffs" I put my hand near the variable condenser, shunting the primary of the second step for a few seconds, the signals in- crease almost 100 per cent, and then fade to normal. I happened to do this the other evening while our neighbor, who is an expert, and consulting engineer for a large radio company, was making a neighborly call. He looked surprised for a few seconds, then called What circuit are you using?" "Oh, look inside the cabinet and figure it out," Friend Husband very airily told him. Now our neighbor is working feverishly nights, and his wife said that he won t even sleep nights. I wonder if he has discovered something that we have been doing right along, and never took time to find out what caused it. "There goes another chance to make a million, maybe two for all you know," remarked Cousin Kate, "just be- cause this one time you were not inquisitive, and now you won't ride in Rolls-Royce." * * * P H. and myself have started a "Radio Supper Club." We * • have gathered together all our enthusiastic radio friends, "chipped in," each to the full extent of his or her means, and have bought a real DX set, which is now installed in the draw- ing room of one of our more fortunate members, who has more room in her home than she can use. Every Friday evening about 10:30 we dance and nibble on a few choice tid-bits, and "a good time is had by all." We find it much more convenient to do our dancing and eating in a radio atmosphere than to endure the unpleasant necessity of having amusement superin- tended by a police officer or a plain-clothes man. Radiograms THE first actual attempt of two amateurs — one George H. Pinney, of South Manchester, Conn., and the other Leon Deloy, of Nice, France — to establish two-way communication between America and France was not entirely successful. Mr. Pinney, while heard in France, could not pick up the French amateur at his station. Mr. Deloy was heard attempting to answer by E. F. Laufer, owner of station 2AQP, located at 699 East 137th Street, New York City. The delay in reporting the French amateur's signals was due to the fact that Mr. Laufer wished to verify the signals before making the story public. It would seem that the French amateurs are paying more atten- tion to their receiving apparatus (which must be really up to date, from all reports) than to their transmitters, but just give them time. That's all they need! * * * THE American Legion Show of the S. Rankin Drew Post, which is composed entirely of theatrical and publicity men of this city, will broadcast the entertainment for the benefit of the radio public. The Legion will have the use of the Times Square Theatre through the kindness of the Messrs. Selwyn, and will broadcast by means of relaying the signals over special wires to the broadcasting station. * * * BY the aid of radio, the Aeromarine flying boat, The Buck- eye," was recently called upon to perform an unusual service. Shortly before the eleven-passenger flying boat left for its first scheduled trip from Miami to Nassau, a wireless message was re- ceived from Carter De Gregory at Settlement Point, stating that his mother was seriously ill and that he had to be taken immediately from the west end of Grand Bahama Island to Nassau. Mr. De Gregory was instructed to board a ship in the harbor, and the flying boat would come alongside and pick him up, and take him to his destination. * * * IT has recently been proved that long waves are not necessary for transatlantic communication. During the recent tests, radio communication was established between Europe and America by the use of short waves, the longest of which was 400 meters. This conclusively proves the fact that it is not necessary to use waves of 15,000 and upwards in order to transmit long distances. • * * THE bane of a radio operator's existence may soon be eliminated, if a new call bell system, developed by an officer of the Portuguese army, proves successful. By means of the in- tended system, it will be unnecessary to continue long watches. S.S. Empress of Scotland's Radio (C. Photonews) The Empress of Scotland has one of the best equipped wireless on transatlantic steamers. It is equipped with the new 3, MS meter transmitter and direction finder, and has a most complete radio Wm, J. Howlett, Chief Radio Officer, is listening- in. Digitized by Google

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RADIO WORLD If The Week with the DX Nite Owls i All on One Tube From Marshall Beaman, SharpavUk, AM a constant reader of Radio World. _ In the January 20 issue I see Mr. Sheron has receiver 1,500 miles with his set, which is described as having three tubes. I only use a detector and I have a record of 2,200 miles. January 23 I received KNJ, Roswell, New Mexico. I received Cuba, PWX, several times. My set in- cludes a 23 plate variable condenser, a variocoupler which I constructed, a grid leak and grid condenser, phone condenser, pair of Federal phones 2^200 ohm, one U. V. 200 one socket, 6 volt A battery, 22}i volt B battery, rheostat My antenna is 125 feet long. Here are some I have heard: WW], WCX, KOP, WLK, WOH, WLW, KDKA, WGY, WOC, WBAP, WMU, WHU, WSB, WOR, WAAF * * * Henry Is 12 Years Old From Henry DeOwrt, 1M South Monro* S tract, Columbus, Ohio T AST night February 2, I heard the *-* following stations with a one-bulb set very clearly: WGY, WMAQ, WWJ, WBF, WOR, KDKA, WLAG, WDAD, WCX, WCAH, WOC, WAAN, WDAP, WJD, WSB, WSY, WJAX, WLW. I am twelve years old, and I built the set myself, using a regenerative hookup. I trust you will print this in Radio World under the DX fiNite Owls." I think I have made a good record for one night, but am hoping for better luck. * * * Mr. Keating's Competitor THE Editor of RADIO WORLD srffl bo ploMiil to receive sketches of hook-ups draws carefully in black ink or heavy pencil from the "DX Nit* Owls" who send in records with a view to puhHshing them. Send hook-ups of your sets, provided they contain something unusual. Send, also, the names of the various makes of apparatus you are using. Make your letters brief and Informative. Write on one side of the paper only. The letters aad hook-ups will be pub- lished m the earnest possible numbers of RADIO WORLD. Mr. Keating, but my set is not a freak. My reception is not due to reradiation. The above stations have been heard con- sistently before and after local broadcast- ing, sometimes as many as four or five stations an evening. They may discredit our results, but they are welcome to come and see for themselves. • » • A Record of 267 From Carlton D. Shulta, Fort Plain, N. Y. AS you ask me for some of my DX records I wrote you once before and fave you my report but since then I ave built this set to five bulbs and I now heard by voice. It must be remembered that I have heard 267 different stations in alL As I am not able to read code I can give you only what was heard by a friend who called one evening, who can do so. He recorded several ships, both from the Atlantic and Pacific, and many stations located in different parts of the United States. I would like to hear from any one using this hook-up. With a Combination Long and Short Wave Receiver i W. Crosby, 1st lientsnaut. P. A, dfe JCAF, «t West Ufa St, N. Y. N.' a, New York City. I AM enclosing a drawing of a combina- tion long and short wave radio re- ceiver which may be of interest to some of your readers. This set has given me excellent results over a period of 2$4 years. Using one U. V. 200 and Baldwin phones I have copied broadcasting sta- tions in the United States as far west as Denver and. from Winnipeg, and amateur signals from every district in the country and parts of Canada. The short wave part of the set is very efficient It is possible when using de- tector and vocaloud to copy nearby sta- tions such as WJZ, WEAF, and WOR, I Variometer 6- \ Variocoup/er + Shiefded Shafts Grounded Ave, St. Missouri. TWAS surprised and interested to note * how similar Mr. Keating's and my own results are. I am the owner of a crystal set without amplification. Music and signals from our local station, KSD, can be heard distinctly aU over the room, without using the loud-speaker. Mr. Keating believes that his results can be duplicated. They have been. The list of broadcasting stations are as follows: WOC, WCX, WWJ, WDAF, WHB, WDAP, WSB, WGM, KDKA, WBAP, WGY, about a thousand miles distant! My set consists of Western Electric 509W, 2200 ohm phones, a home-made 1-slide tuner 4% inches long, wound with No. 26 B & S wire ; aerial, 2-wire, 85 feet long and 36 feet high. No phone con- denser used. These stations have been received with both galena and silicon. There is nothing strange about the hook- up. It is a simple one, known to all ama- teurs. , Now why don't other owners of crsytal sets get the same results? There are many who discredit my reception, too, -■* i Shematic diagram Illustrating the hookup described In WUBam W. Crosby's letter on this page. Change over from long to short wavss Is accomplished by means of anti- capacity switches. send you the following: I hear KDYX, Honolulu, quite often, and on one occa- sion I heard KUG, also Honolulu; WLAY, Fairbanks, Alaska; KDYO, San Diego; KQI, Berkeley; KDZG, San Francisco; KDYQ, Portland, Ore.; PWX, Havana. These are the most distant stations I have over one and two rooms quite distinctly. The short wave part of this set is very carefully shielded, all metal parts not in the circuits being grounded. I should be glad to furnish any further information desired to any of your read- ers upon receipt of stamped envelope. Diagram of the hookup with which Mr. Schults (sss letter) has heard 2*7 stations. The first two tubes last two as audio frequency amplifiers. Connect in fkrialatflanc/B Digitized by Google

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20 RADIO WORLD Much Experimenting Decided New York City to Establish Municipal Station at Elmhurst, L. I. By Hon, Grover A, JVhalen Commissioner of Plant and Structures of Greater New York GROVER A. WHALEN, Commissioner of Plant and Structures of Greater New York, announced a few days ago that the installation of the Municipal Broadcasting Station is to proceed without delay. This enterprise was authorized by the Board of Estimate and Apportionment on June 2, 1922, but the actual installation of the apparatus was deferred pending the com- pletion of exhaustive tests and experiments conducted with the co-operation of the Western Electric Company, in order to ob- tain necessary information so as to assure such installation as would be absolutely effici- ent in operation. "The result of these experiments," said Commissioner Whalen, "has been of great value to radio science and has necessitated radical changes in plans, which will assure New York City having one of the most effective broadcasting stations in the country. "The studio, reception room and control rooms will be in the Municipal Building, as originally planned, convenient to the City Departments and to the people. The trans- mitting station will be erected on city prop- erty at Elmhurst, L. I. The antenna towers will be 200 feet high and 300 feet apart. The transmitting station will be connected by cable to the studio and main broadcast- ing station in the Municipal Building. Perfect Radio Service for New York City "The location of the station at Elmhurst has been carefully chosen for its electrical advantages in launching the electrical waves into the ether. In addition, it is in the center of that locality from which it is expected from the results of the tests that strong signals will be obtained meeting all condi- tions of perfect service for the people of the city and for those at large. "These changes in the original plans had their inception in the desire to locate the transmitting equipment so as to assure the sending of strong signals to all parts of the city for the benefit of the owners of small crystal receiving sets as well as the owners of the more expensive tube sets throughout the country. "It was realized that the Municipal Build- ing, a steel structure, 580 feet high, set in a nest of tall steel structures, presented cer- tain prima facie difficulties as a site for the location of the transmitting apparatus, and it was decided to determine definitely exactly what these difficulties were — whether they could be overcome or whether the adverse conditions made another location advisable. The officials of the Western Electric Com- pany, which was the low bidder on the con- tract, agreed cordially that preliminary tests were desirable in order to give assur- ance of the efficient working of the station, and decided to conduct these tests with the department engineers, supplying all neces- sary apparatus, without cost to the city. "The Municipal Building, as far as the launching of radio waves is concerned, has unusual dimensions not calculated from an initial survey to be beneficial, but not pre- cluding failure. It is higher than other buildings used for this purpose, being 580 feet in total height. It has a centrally lo- cated tower, above which it would be im- possible to locate the antenna and the shield- ing effect of this tower was feared. It is also surrounded by and is in close proxi- mity to other steel buildings of a massive structure, such as the Woolworth Building, and the absorption, deflection and shielding from this source had to be considered. Temporary Installation for Test "In order to make the test, it was de- cided to install temporarily in the building a 100- watt transmitter, erect a small an- tenna, using the tower of the building as one of the supports, transmit signals, and actually measure the strength of them, at different points on the circumference of a circle surrounding the building. The meas- uring instrument used was a specially de- signed extremely sensitive receiving set, em- ploying what is known as the double detec- tion, intermediate frequency amplification method. Reception was made on a loop an- tenna and the signal strength recorded on a microvoltmeter. By means of a separate os- cillator energy of a known amount enough to produce the same deflection on the scale as that prduced by the signal was then sent into the antenna and the electrical character- istics of the antenna being known, the strength of the field produced by the signal in microvoltmeter was then calculated. In this way, it was possible to know exactly what may be expected of a broadcasting station at this location. "On September 15, 1922, the temporary antenna was erected. It was of the fiat top inverted L type, made up of four strands of No. 18 phosphor bronze wire, 75 -feet in length. It was supported between the bal- cony above the 39th floor of the building and the roof of the 25th floor on the north side and the lead-in taken from the lower end to the transmitter on the 25th floor. Testing under an experimental license was begun on September 28, 1922, and continued until December 27, 1922. Lloyd Espencheid, of the American Telephone and Telegraph Co., and R. A. Heising, of the Western Electric Co., had supervision of the test and their experiments were carried out bjr E H. Hall and I. C. Crowley, under the direction of S. H. Willard, all of the Western Elec- tric Company, in conjunction with men from the Department of Plant and Structures. "When the operating conditions had been found giving the best field strength, meas- urements were made with the measuring set at Atlantic Highlands, N. J., Cliffwood, N. J., Rahway, N. J., Maplewood, N. J., Passaic, N. J., Englewood, N. J., Yonkers, N. Y., New Rochelle, N. Y., Great Neck, L. L, and Lynbrook L. I. Results Are Most Interesting; "At the same time field strength meas- urements for comparative purposes were made of the signals of the Western Elec- tric Company's station WEAF, on the same wave lengths, this station being recognized as a very efficient one. The results ob- tained from this test were most interesting. The curves of field strength for the two sta- tions were similar in shape. In certain di- rections, such 'as Passaic, signals were strong, while in other directions, such as Yonkers, signals were weak. This condition is evidently caused by the absorption and deflection of the waves caused by all of the steel buildings in lower Manhattan taken as a whole, to the contour of the land rivers, valleys, etc., and finally to local receiving conditions at the points where measurements were made. This condition would therefore exist for any station located in lower Man- hattan and could not be improved. "The strength of our signals was, how- ever, much less in practically every direc- tion in comparison to the strength of the signals from station WEAF. This condi- tion we encountered in all of our tests: namely, weak signals on the 360 to 400 meter wave lengths upon which we will be re- ?uired to operate, and strong signals on the 50 to 600 meter waves which we will not be permitted to use. This effect is attrib- uted to the dimensions of the Municipal Building itself. The building is 580 feet from the curb to the top of the tower or approximately one half of a 400 meter wave length. It persists in oscillating, therefore, at a frequency which causes opposing volt- ages to exist between the free end of the antenna and the ground. Throughout all of the experiments attempts were made to prevent the building from oscillating by employing various combinations of antenna counterpoise shields and filter circuits placed between counterpoise and ground, etc. Some measure of success was attained, at least enough to justify continued efforts, but not with satisfactory results. Efforts were made to change the oscillating period of the build- ing to one which would strengthen instead of weaken the signals, by the use of reso- nant and anti-resonant circuits between counterpoise and ground, and between an- tenna and ground, but with no greater suc- cess. "It was then decided to locate the trans- mitter in a room on the thirty-fourth floor of the building at a height above the street level of approximately 450 feet. An um- brella type antenna was erected consisting of eight strands of wire extending from above the thirty-ninth floor of the tower to the roof above the twenty-fifth floor on the north and south sides of the building. The tower was completely surrounded by a shield consisting of twelve wires extending its entire length, and counterpoises consist- ing of six wires each were used above the twenty-fifth floor, on both the north and south sides of the building. On November 28, tests were begun here similar to the ones made on the twenty-fifth floor and better results were obtained, but they were still not what they should be. In tins case die antenna was driven from the top down, and it was from this location that the tests for field strength made from different locations on the circumference of a circle surround- ing the building previously mentioned were made. "In the final effort a very novel experi- ment was tried in which the antenna wires (Continued on next page) Digitized by Google

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RADIO WORLD 21 Commercial Interests May Take Over Naval Radio Stations Closed Recently SECRETARY of the Navy Denby has di- rected that four naval radio stations be sold, four others abandoned, and two radio compass stations be closed and dismantled, which proposed action was predicted in Radio World recently. In carrying out the recent recommendations of the Rodman Board in the interests of increasing fleet ef- ficiency, particularly in communication, die Secretary is disposing of unnecessary radio stations. The stations at Cape May, N. J., will be closed and abandoned by naval personnel at once. Ita work hereafter being handled by the station at Cape Henlopen. At Seattle, another station will be abandoned as soon as the Navy Yard at Puget Sound can take over the traffic. Grande Isle in Louisiana has been ordered closed and abandoned, as has also the station at Navassa Island in the West Indies. Radio stations at Baltimore, Md., Mobile, Ala., Miami, Fla., and Port Arthur, Texas, will be offered for sale as soon as Invita- tions for bids can be drawn up. It is also planned to dispose of the station at Man- agua, Nicaragua, when commercial facilities are provided at that place. The War Department has been asked if it desires to take over any of the ten naval radio stations on the Great Lakes, but it is not likely that the Signal Corps will accept any except those at Buffalo and Cleveland. Such stations as the army does not take over will remain closed, as the navy does not need them and cannot afford to continue their operation. Three compass stations on the Lakes, however, will probably be opened in the Spring as aids to navigation. Radio compass stations at Pass a Loutre, La., and St Petersburg, Fla., will be dis- mantled and the land vacated by the navy. Several other stations are being held sub- ject to abandonment as soon as the handling of existing traffic is arranged. In closjng the stations, the Navy Depart- ment does not desire to interrupt traffic in radio, but, on the other hand, as commer- cial traffic was only handled when other facilities were lacking, officers are of the opinion that commercial interests may now be induced to open general traffic stations at points previously covered by the navy. The prime purpose of naval shore radio sta- tions is to aid the fleet, and when a station ceases to benefit the fleet, it becomes a lia- bility to the Government instead of an asset. Can It Be So? "Pa, what does broadcasting mean?" asked Clarence. "Telling a secret to a woman, son," re- plied Pa. — Cincinnati Enquirer. A Matter of Hair Now that the White bill has been passed, a lot of amateurs will have to have their "permanent wave" re-hooked, or they will be completely out of style. (Continued from preceding page) were lengthened so that they extended down the sides of the building to a point below the eighteenth floor. The total length of the antenna wires was equal to one half the height of the building. By this arrange- ment it was hoped that the voltage in the antenna, and in the upper half of the build- ing would oppose and neutralize each other, leasing the lower half of the build- ing free to radiate. This condition, theo- retically would be the same as operating from a building one-half as high or one- quarter higher, in which case the height of the free end of the antenna would be one- quarter or three-quarters of a wave length, and the voltage at the free end would be a maximum instead of a minimum. This test, however, did not give the results desired. "In view of these results it was decided that efforts to operate the broadcasting transmitter from the Municipal Building cease and a new location be chosen for it. "It has been realized that the radio public has been anxiously awaiting the advent of the Municipal Broadcasting Station, and has been wondering why it has not been placed in operation. It has been necessary to exer- cise patience in regard to the time required for the tests mentioned and for many rea- sons. It was desirable, if possible, to op- erate from the Municipal Building, one rea- son being that in this case it would not be necessary to_ erect towers, the central tower of the building being used for the support of the antenna. The information and data obtained from the tests are of much scientific interest and value, there not having been much data obtained previously in regard to the functioning of antennas when erected on the tops of high buildings. In order that this information obtained be of value it was necessary to make the tests with precision and thoroughness and this, of course, in- volved time. ' "The idea of a city-owned broadcasting station was promulgated on March 17, 1922, when, at a meeting of the Board of Esti- mate and Apportionment, a resolution was adopted approving the suggestion of Maurice E. Connolly, President of the Borough of Queens, relative to the establishment of a Municipal Broadcasting Station and recom- mending the appointment of a committee to conduct a thorough investigation. "To carry out the purpose of this reso- lution, Mayor Hylan appointed a committee on which the following gentlemen were asked to serve: Rodman Wanamaker, Philip Berolzheimer, Maurice E. Connolly, Lloyd Espenchief, S. G. Rhodes, Merritt H. Smith, Arthur S. Tuttle, Sanders A. Wert- heim and Grover A. Whalen. This com- mittee m its report to the Mayor on May 2, 1922, after having sought the advice of many radio experts and after having gathered considerable data on the subject, stated that it believed it was the duty of the munici- pality to immediately take steps to erect, under city control, the most modern and best equipped radio broadcasting station in the country, and that the importance of munici- pal broadcasting was so far-reaching, and its possibilities so limitless, that it felt the city would be derelict in its duty were it not to take the necessary steps at once. "On June 2, 1922, the Board of Estimate and Apportionment appropriated the sum of $50,000.00 for the purchase and installa- tion of a complete radio telephone broad- casting station, including antenna structure, power supply and voice amplifying apparatus with loud speaking, receiving and amplify- ing sets." 9Vb Wireless Receiving set is complete ° without r WHEN your boy points to the Mag- navox trade mark and says "Dad, that's the real reproducer," he sums up pretty much the whole story of Magnavox supremacy and radio enjoyment. To enjoy all that radio offers in the way of daily concert, lecture and news, ask your dealer for a re- ceiving set equipped with Magnavox Radio, the Reproducer Supreme R-2 Magnavox Radio with 18-inch horn: this instru- ment is intended for those who wish the utmost in amplifying power; for large audiences, dance halls, etc R-3 Magnavox Radio with 14- inch horn : the ideal instru- ment for use in homes, of- fices, amateur stations, etc Model C Magnavox Power Amplifier insures getting the largest possible power input for your Magnavox Radio. 2 Stage 3 Stage When you purchase a Mag- navox product you possess an instrument of the highest quality and service. Magnavox products can be had of good dealers every- where. Write us for copy of new illustrated booklet. The Magnavox Co. Oakland, California N. Y. Office: 370 Seventh Ave. J/fAGNAVOX M J&dio DheSiepYodueer Supreme Digitized by Google

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22 RADIO WORLD Adrerttdac Rates, Display, $5 JO per inch, $15040 per page Radio Merchandising dasaifted Quick-Action Adrertistnf, 5 cents per word Telephone Bryant 4796 Hoover Loses Test Case THE District of Columbia Court of Appeals recently overruled Secretary Hoover when he refused to issue a license to broadcast to the Intercity Radio Co;, of New York City. The license was withheld, the court was told, because the station in- terfered with the transmission of gov- ernment messages from naval and military stations. Recognizing the fact that inter- ference would be caused, but that this fact was also recognized by Congress, Justice Van Ordsel declared that the law under which all radio licenses are issued embodied provisions for the Heard at the Radio Counter Episode XIV "Good morning-. Is there anything- that I can do for you?" "Why, yes, I wonder if you could tell no if it is possible for me to purchase a set that does not need an outside wire." "Certainly. The latest thing- in radio sets is a set using* a loop, in connection with radio frequency." "I don't understand anything' about that at mil The only thing I know is that my wife wants a set, and the owner of the house refuses to 1st me put up a wire on the roof. So I thought I would try and get one that didn't need any "If you will step over here, I will show you sereral different types that operate on just a small inside loop aerial." "But I don't want anything that will freeze us all out." "Freeze you out! I don't understand?" "Well, don't I have to keep the win- dows open when I use those things there?" "Why, of course not. This set will work in a closed vault under the ground." "Oh, I must be dense, I thought that you had to leave the window open m order to catch the music and talk." "Absolutely not. Now, here is a nice little set, and it uses only three tubes. Positively the most economical set on the market. Then here is another type that is very popular, but it uses five tubes." "Well, which is the more efficient? I don't care if it costs a tittle more.' You see, my wife is an invalid, and the best isn't half good enough for her.' You just pick out the best one you have in the shop — say, is all that music coming from that little set?" "Yes, sir. That it, this set over here, minimizing of such interference, and that that was no reason for refusing the license applied for. The court said in part : "The only discretionary act is in selecting a wave length within the limitations prescribed in the statute which, in his judgment, will result in the least possible interference. The issuance of a license is not dependent upon the fixing of a wave length. It is merely a restriction entering into the license. The wave length named by the Secretary merely measures the extent of the privileges granted to the licensee." using an extra power amplifier, but that is not necessary, if you want to use it in one room only. In that ease, the outfit as you see it is sufficient." "Well, send it up to my house, and have a man up there tomorrow after- noon, to show us how to work it will you?" "Most certainly, I will attend to it my- self personally. Is this your address?" "Yes. Will you see that it gets up there soon." "Yes, sir. Good day." Half Million Dollar Order for Westinghouse 13 ECAUSE of a large increase in traffic, the Long Island Railroad, which handles probably the heaviest suburban traffic in the world, has just purchased from the Westinghouse Electric & Manufactur- es Company 40 motor car equipments, 20 trailer car equipments, and four baggage mail car equipments. The baggage cars will be equipped with Westinghouse type 308 D-7 field control motors and Westinghouse electric-pneumatic control. In order to take care of the increase in power demand when this new equipment is put into service, it hat been necessary to increase the sub-station capacity of the railroad, and an order has been placed, also with the Westinghouse Company, for one 4000 kw., and one 3000 kw., six phase, 25 cycle, 650 volt, converter with the necessary transformers. The entire order amounts to over a half a million dollars. Coming Events PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Opes from September, 1922, to May, 1921. SECOND DISTRICT RADIO CONVENTION, Hotel Penaaylraaia, New Tark City, March 1, X. and 3, 1923. FIRST UNIVERSAL EXPOSITION OF IN- VENTIONS AND PATENTS, Grand Central Pal- ace. New York City, February 17 to B, laotaaWs, New Radio Firms _ (The new firms and corporations men- tioned in these columns can be reached directly or by communicating with the attorneys, whose addresses are given when ever possible.) - Eagle Radio Corp., Manhattan, $5,000; J. J. Reiu, W. C Johnstone, L. K. Knowleon. (At- torney, }. E. Kinsley, 120 Broadway, N. Y. C) Electric Service Engineering Corp., Manhattan, electric auppliea, 150,000; L Gottlieb R. B. Dark*. (Attorney, J. E. Ankus, 3S Park Row, N. Y. C) Newburgh Radio Shop, Newburgh, N. Y., $10400; M. M. and J. H. Hincmon, Jr., T. Cray. (At- torney, W. C Olaen, 30 East 42d St.. N. Y. C.) Nowak Electric Co., Buffalo, general contract- ing, 150,000; J. J. Nowak, R. F. Hong, P. Masnr. (Attorney, R. W. Werner. Buffalo, N. Y.) Nelson Electric Corp., Manhattan, 150000; J. H_ Nelson, W. A Bine, J. W. Wilford. (Attorney, Subway Electric Shop, Richmond Hill, N. Y.) Radio Stocks (Quotations as of February 7, 1923, fur- nished by Frank T. Stanton & Company, 35 Broad Street, New York City, Specialists in Wireless Securities.) Stock Bid Asked American Marconi Stamped 5c 20c Am. Marconi Unstamped... $5 $7 American Tel. & Tel 122J< 122*4 Canadian Marconi 2*4 3% De Forest Radio 7 10 Dubelier Condenser 6 6)4 English Marconi com. 11 15 English Marconi pfd. 11*4 15*4 Federal Tel. Calif 5*4 6 General Electric 187*4 188 Mackay Company com 105 107 Manhattan Elec. Supply.... 54*4 55 Marconi Int. Marine 8 10 Radio Corporation com 3*4 3$i Radio Corporation pfd 3% 3*4 Spanish Marconi 1 3 Western Union 112*4 113 Westinghouse E & M 62*4 63 Western Electric in the East THE Western Electric Co., whose headquarters were formerly in Chi- cago, have moved to New York. This change was brought about by the build- ing of a large plant in Kearney, N. J. All department heads, with the exception of C. G. Stoll, will hereafter be located in New York City. The Recent South Sea Storm ALL EFFORTS TO REACH SAMOA BY RADIO, after the seisomographic observatories throughout the country re- ported a terriffic 'quake in the Pacific, in the region of the Hawaiian Islands, were in vain for several hours. The later reports showed that the earthquake had caused tidal waves in the vicinity, seriously damaging the station, and communication was not pos- sible until the damage was repaired. The reports from the observatories stated that the records showed that the shocks were the worst in years, and had been recorded all over the western hemisphere. Digitized by Google

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RADIO WORLD 23 Answers to Readers /WOULD like to know how to make a good one tube set. Where can I get a description for making one T— Clifford Vet- sey, 104 East \6th St., University Place, Neb. We refer you to Radio World No. 43, dated 'Jan. 20, in which you will find an excellent article, with all plans in full work- ing size, and everything minutely described for you, by Ortherus Gordon. • * * 1. W hat is the best type of recehring ap- paratus to enable me to receive from 1000 to 1500 miles r 2. Is an inside antenna as efficient at the regular outside antenna T 3. What it the probable cost of such out- fits r 4. Where cm I get a book, that will ex- plain radio to mef—Thos. Ross, 43 Brooks St., Sanford, Me. 1. We advise either the popular three unit regenerative circuit with one or two steps of audio frequency amplification, or a radio frequency set, with two steps of radio fre- quency, detector, and one or two steps of audio frequency. 2. If you intend using radio frequency, we advise the inside loop. Otherwise, use the outside antenna. 3. We cannot discuss the various prices of \SP0RT Complete Regenerative BULB SET $13-45 ■* POSTPAID Outfit includes tH Volt BoE—Ftf TaO Varteeonplsr with M tap*— I steae a Plate Variable Condenser t Kaobe and DU1» — Rhaoatat— fiockat— Orid-Laat Caa- dansir Pry CeD-OK Volt Plata Battarr- T Bindlne Poeta— Also Drilled Paaal Eaay ta «,nam>U, With Extra Sensitive ^ ^ 6 70 SS.M Breads* Flahar Varioeaupiar Fiahar Varioaaatar SIJS 41 Plata Cottdansera tlJS S Plata Condensers SLS WJ>. 12 Transformer 1% Volt Fraach Tuba far Dry Call. Guaranteed to Work MARTIAN BIG FOUR Tha Wonderful rUfh Grade Crystal Sat. Cam bo oaad with 1, X. S, or 4 bead seta. Tha wbols busily Helena in. Coots notbJasj to koop up. ita tha lattarlaa $6.50 Any ana can tnotall am Bi« Fear. GOODS SENT PROMPTLY ON RECEIPT OF MONEY ORDER OR CERTIFIED CHECK. PHILIP'S 123 Nassau St* New York City competitive apparatus through these col- umns. See advertisements. 4. We refer you to the books sold by The Columbia Print advertised in current is- 1. Kindly give me the details of the vario- coupler, used by Mr. F. J. Rumford, in kit article on the two tube super-regenerative receiver. 2. As the English Government makes all owners of radio sets submit their diagrams, with details of all the receiving circuits and sets, would it be permissible for me to build this sett I understand that this circuit it an American patent. — C. H. G. Crossman, 17 Hougoumont Ave., Waterloo, Liverpool, England. 1. A suitable coupler for this circuit can be made as follows : On a tube 4 $4 inches in diameter, and 6 inches long, wind 100 turns of No. 22 SSC wire (single covered silk wire), taking taps off the first 10 turns, and then tapping every 10th turn. Do not shel- lac the winding. Wind the rotor full of the same size wire. The rotor should be 3J4 inches in diameter. No taps are taken off the rotor. This coupler will tune to approximately 1000 meters with an ordinary antenna, with a .001 condenser shunting the primary. 2. We do not believe that there is any in- fringement on a patent in this case, as you are constructing the set for your own use, but we advise you to take the matter up with an English patent attorney, as the laws vary in different countries. • • • 1. What are the sites of the primary, secondary and tickler coils used in the hook- ups published on page nine of Radio Woklo dated December 30? 2. Will this circuit bring w signals any louder than the regenerative set using the regular 6-volt tubest 3. Can all three windings be mad* on the same tubef— William E. Johnson, Wayne, Neb. 1. The construction and arrangement of the coils used in the hookups you mention were fully described in Radio World, No. 26, dated September 23. 2. If these circuits are carefully hooked op and the directions followed out remark- able results can be obtained with them. 3. See explanation of bow these coils were constructed in issue of September 23. • • a 1. How can a test be made to determine if there it a broken wire in a transformer T 2. Is the enclosed diagram of on* stage of audio frequency correct? I have con- nected it as in diagram, but cannot get it to work. — L. C. Comic, Anthony, Kan. 1. The simplest and best test as tc whether there is a break in the wire (open connection) is to test the windings separately with a pair of phones and a battery. If, when the current is made and broken, there is a click in the phones the transformer is O. K. If there is no re- D-X- (DISTANCE) The Ambition of Every Fan lor DX CDis- D-X- RADIO COMPANY Radio instruments designed taaoc) Work. To receive distant stations your instrument most bo (milt with aropar i«nt. And that saaaas tha D-X- w, , Comaaai^-partietuarly since wa ofter Ugfaeet quality radio parts. at lowaat price*. SPECIAL GENUINE FISCHER lSf* VARIOCOUPLER M TAPS, SEVEN Dt UNITS SOLDERED LEADS BEADY TO USE REGULAR PRICE. .$5Jt SPECIAL PRICE. Remittance must accompany all Orders. Checks or stamps not accepted. Mar. cbaodis* shipped post paid east of FREE CATALOGUE ON REQUEST D-X-Radio Co. US Uberty Street Now York Ctty- sponse there is a break in the windings. Test both the primary winding and secondary windings separately in this manner, and use a very weak current A single dry cell or flashlight cell is sufficient. 2. Yonr diagram is correct. Test the transformer as described. See that your tube is making good connection with the lugs in the socket, and that the positive connection of your B battery goes to the plate. A GILBERT ft SULLIVAN opera. The Pirates of Penzance," will be broad- cast by WGY, the General Electric Com- pany station at Schenectady, N. Y„ Tuesday evening, February 20. Practically the same group that sang "The Mikado" and "Pina- fore'' at WGY will be heard in this produc- tion, which is put on as a resuh of many hundreds of requests for more light operas. BIG MONEY IN of Feb. Srd laeas RADIO WORLD RADIO PARTS PRICES SLAUGHTERED 1 11.00 Kiss Aslltaaa Use Swthtr Hm. . . It tj 5.00 Vint Oi/pltn 2. SO 9.7) Varla CaesUra 1.7} 7.00 All Wm Oaeslar. 1000 »a1er» • 19 S.00 VvMitei . 1.71 1.79 9 Plata Veriest* OaeSaaaar . . l.tS S.7S 19 Plats VariaMs I.SS B. B. RADIO CO., ttSS M.7S St Para OaStaeter .11.7$ I.SS Rhawtat II I 50 Klauer Vers lor HkMatet I. It I.SS 1- Hiri RaOSarSaal .«} (0 V T. Seatata SS I.SS iiv, V. Co i lass a. •attar Ns 7» BetsarMa I. is i.7t it* v. culm a. aia■■ tekaa . .. 4.M Pfcaaaa. J»a«l eeelltr. 1200 1.75 BaooaXTW. N. T. Digitized by Google

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24 RADIO WORLD Ex- President Wilson Has Badge EX-PRESIDENT WILSON wai the first and probably only honorary Chief Radio Inspector of the United States. Although few fans will recall it, President Wilson was presented with the badge of Chief Radio Inspector by Secretary of Commerce Redfield during the Safety Exposition at the National Museum in 1916. At the opening of the exposition Secretary Redfield, who was waiting to welcome the President to his exhibits of radio and other safety ap- paratus, "robbed" the Chief Inspector of his badge, so that he might add to the cere- monies by decorating the President. Some- where among his possessions, it is under- stood, Mr. Wilson still cherishes this title. Siffer Lemoine, Radio Engineer of the Royal Swedish Telegraph Board, is in the United States studying the American radio systems and to confer with Gov- ernment radio officials. A Wonderful Opportunity The Futera Dlrliloo of THE RADIO CORPORATION OP AMERICA aeeept no Ma or Inerpa- rleoaed appUeaata In tbelr oerrleM aa Wrralan Opnln otter than our Graduatae. Inaaatlfate too adraataw of. fond thrown ukini either our BOMB BITOT or BM8I- DKNCB eouraa In Radio. RADIO XHSXRUTB OF AXKBIOA Formerly Marconi Inttitute Now York Ctty Marion Davies Thru the Air Marion Davies, the motion picture star, gave a talk over the radio a few nights ago on "How to Make Up for the Movies." The star of Cosmopolitan Pro- ductions told how to apply powder or grease paint to achieve just the right ef- fect for the camera. The message was picked up all over the country. It was broadcast from station WEAK, 24 Wal- A FLASH LIGHT WITHOUT A BATTERY! I 1 A Mow. tlMtfy. Brllllaat WMte Ufkt Prepaia 14.00 A Dyaane la tea Itae* ""' " Pain of laMaltehr Daaarlptln Clreefcv Pereetaal m Raeueat Coot Kiri W. Kalokt. Daot. R 4S Humor St Veer Hao* Super V.T. Socket Wklta ParaaWo 10a Bravo Praaalala 39a Banana BaJullta ....40a 50* discount in 100 lott L ft. I. DmMo Mff. Oo 132 Pltouui Straat Prorloaooa. R. I. SIMPLEX SPECIALS AarMa Sr. RaMhrer OSS.tO Aerlala 2-Step Aapllter 01.20 Balovla Tyaa "C" Pkaaaa io.IO Srawal Fbtao Oataatara 1.00 Matra liOS-Okai Pkaaaa 3.00 Deklller Daaao Aariaia 1. 10 Teeter Bettary Ckoroar it.oo Dlataorapk sato-Oha Pkaaaa (.40 KaaaaoV Tyaa SOI Raaalaar 00.01 KaaaoaV 321 2-Step Aaiplltor 40.00 Beraeaa 22 y, V. "»" Bottarlaa 2.03 Brake CR-S ar CR-S Raaalaar SS.M Brake RORK 2-Stao Anplrter 4S.SS Braka CR-0 Raaalaar aad 2-Sta* 112.00 Waat SMet Han aa* 3-Stap 122.30 CASH WITH OROtR SIMPLEX RADIO SUPPLY CO. 1000 LAFAYETTE AVE. 8T. LOUIS. MO. AIR-MUSE Receiver. $£.00 Range 50 to 500 Miles The faroouo AIR-MUSE receiver conaieta of Oak cabinet, bakelite panel, aelectiaa and primary tuning. So aimple a child can inatall and operate it Broadcaating; ata- tiona program a heard perfectly. TUa re- ceiver ia absolutely guaranteed or money refunded. Sent poet paid anywhere m the U. S. A. on receipt of Express or Poet Office Honey order. WOO Ohm double headact Set complete aa uluatrated All other radio acceaaoriea at manufac- turera' pricea. Detroit Radio Company ONF ' ' Uth STREET NEW Y' Dear* W Broadcast Bill's Radiolays ker Street- New York- By William E. Douglass MY wife has got a habit, Tuesday nights, of "lissnin* in" when they send out their talk on styles. Of course I can't blame Min but last week when the parson came to make his monthly call she had him listen to the talk. It pleased him??? Not at all. The chap who did the speakin' seemed to me to be right clever but Parson Brown wux horrified. You'd never guess why, never. The talk begun by tellin' how the girls should wear their hair an' then he told the ladies too what they had ought to wear. Now while I'd like to tell you more I haven't got the heart so I'll just quote some extracts so you'll get, at least, the part that Parson Brown objected to. Perhaps he's justified but as fer me an' purty gals I'm always on their side. "The skirts this spring are longer without going to excesses;" "Behind Dame Fashion's last decree regardin' length of dresses the ones with skinny props, of course, are glad enough to hide but for the rest, oh well — you know — let conscience be your guide." I tried to calm the parson, but as soon as I'd begin he'd interrupt me sayin' "It's an in- strument of Sin." "What's that?" I sez real peevish like, "You let me have my say. If you had one of these here sets you wouldn't talk that way. Last week I heard four ser- mons each one from a different place. I tell you Radio's a boon fer all the human race." We both got so excited Min thought there would be a fight, but I convinced the Parson, after while, that I wuz right He's comin' over Sunday after church to "listen in" an' pick up other services as fast as they begin. I told the boys about it when I met 'em at the store. They thought that it wuz funny an' you'd ought to heard 'em roar. Next Tuesday night the boys are comin' over so's to hear some more about the fashions we expect to have this rear. An' if they get too noisy "bout the sights they'll be denied, I'll tell 'em that the rule still holds "Let conscience be your guide." Copyright, 1922, Westinghouse Electric & Manufacturing Company. Rado Club Formed at Colby Academy Colby Academy Radio Club recently or- ganized at New London, N. H., is an- nounced by the school. Officers have been elected from the student body as follows: V. C. Buhler, president; Roy Knight, chief operator; Albert Laidbought, vice-president; Quinlon Dodge, secretary-treasurer. Meet- ings are held in Colgate Hall Saturday nights at 6:30. A Record According to letters just received by mail from three different communities in the Ha- waiian Islands, the radio-phone station WHAZ at the Rensselaer Polytechnic Insti- tute in Troy, the largest station in any edu- cational institution, has established a new world's record for long distance broadcast- ing of concert programs, clear reception of both music and speech having been estab- lished at a distance of approximately 5,500 miles. — N. Y. Mail. We'll Say It Is! Isn't it cheaper to invest in some kind of protective fuse in your filament circuit than to find yourself saying, "And that was such a wonderful detector, too — they don't make 'em like that any more?" STANDARD MERCHANDISE AT CUT RATE PRICES Franleokan Plata Rkaaatata t .7S t Franleokan Vereler Rkaaatata I.2S 1.10 Klaaaer Vernier Rkaaatata I.SB -to Kleaaar Vara tar arrtk Dial I.0B I.M • Valt Dataller Take 4.0B 2~23 0 Van AnplMler Take 4.0B S.73 Freakana Varlakle Brie? Leak I.0B .70 CASH OR MONEY ORDERS WITH ORDER. RAPCO PAYS ALL PARCELS POST CH ARSES. RADIO PRODUCTS CO. 147 Weat 23* Straat. Naw Vark City. N. V. RADIO GOODS AT BARGAIN PRICES SSSS Detector Tubea S0JS Amplifier Tubea (4 JO 1VJ-V. Detector or Amplifier (fite atandard eocnet) 2ZH-V. Erearoadr B. Bat*. No. TSS...SLZS 22%- V. Cyclone B. Bait-. An MarcbaacSl Send tor FREE Price LUt. Bergen Radio Supply Co. 000 Bai-fra Ave. New York City A B C of Bp CAPT. V. W. PAOi. TMa koafe anailkie Oka kaale prlaalplea af artatlea. Ma) ken a r HrlflUe la nade lU rtr U Bean la Daavlbaa ken aa ajietaae the, It Baa tail the dlfereat parte af aa atralaai. are aad wkat tear aa. Deeertbn l "" ■feme aad kavtfcer dUTar la eat ae iWtalHne tka odraataaae aw af dkTaraat tjrpaa af atraraft. It plate dutlaaarr af arUtlea ' tan at leadtai airpUaaa. Maple laatraauoaa far aoaeotleoL eaatne; ap mad rUilae alniaaea. A fall anajapkaa of ilirlaaa antral rrlntlpUa la atian aaal natkede af flytaar an Jaeaaaad at laagtfe. Tfcie keek aooeara even eeaaaiea aaa eaa eek deaf TmT \viZ^i<t^m^mST^mdmaaLmmSmmmM with r pUiee. Prtae. 12. te THE COLUMBIA PRINT IBM BtoeaBeaoj, Mew Tarn Oty RADIO BROADCASTING MAP rOB the kaaaat af aad Bean wke ara MaNaUy A a KeNaU? * Oanaaaf ban jaeawaB a paRH- latlaa eaatalalat a aealtt tTmrnmrnttm af fraataat taiaai It ikiei la taa aaal aatMaaken- alra war. ' Kraa th Utba, Th. Bead MaNanp BadU Map af trotted Beats »a iliOO laabaa la alaa. Tba laaarlaaa af iiiiiBiB lM atauana are aftoira kp dtaaaadre aaeaaata. Tha nil lattan af aaak attUna an dna. aha tke aaae laarta of aaak. Tba Badta DlaMata attk an abewD la red aad tke Badta Relay an la Mae. Tine aanee an laaladed. leal Uata ar aUUaoa aad aWiakarlaal I lettara an la tha annua. Oaaiaalaat Price SSc Each THE COLUMBIA PRINT 14SS BROADWAY NEW YOU CTTY Digitized by Google

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RADIO WORLD 2f TmM VARIOMETERS With W Ota R0T0R8-M.il. Statin, Spatial n en ■ran Cm tut Buaklaos, 2(0 to «00 Mators. *-3w Prompt Attention to Mail Oriert B. E. JAR VIS, Inc. 113*115 Msahaala 8trnt Newark. N. J. WE ARB MANUFACTURERS OF FINE RADIO FURNITURE-CABINETS, TABLES AND ROLL TOP DESKS. Hgphwd, it and goIMa oak Expreea paid by ua. Poetags and It will pajr you ta •and far prices aad THE SOUTHERN TOY COMPANY Hiekary, N. C L|\ J% SUPER- • Um lY* CRYSTAL Tha Vacuum Tube". Only Rival" Will Maka V«lr Crystal Set Sailed Llka Sousa's Bud — 50a Eatf. Rata and R. F. Crystals— $1.00. JAYNXON LABORATORY 57 OCV STREET. NEW YORK CITY HEADQUARTERS MeOafJasgs.re at w. 14 stu at Y. oTty. "Lasaasn mm mil ELKAY RADIO PHONE From Factory to You 3000 ohms adjustable head- band, 5 loot cord, every phone guaranteed to give entire satisfaction, ar money refunded. Equal to any tL00 phone on the market. ar Slenay Ordar.°' °' The Elkaj Co., 207 Market St., Newark, N. J R4TENTS To the Mao with an Idea I offer a comprehensive, experi- enced, efficient aervtce for Ma prompt, legal protection, and tha development of hit - Send sketch or model and descrip- tion, for advice at to coat, search through prior United States patents, etc. Preliminary advice furnished without charge. My experience and familiarity with various arts frequently enable ma to accurately advise clients aa to probable patentability before thay go to any pi-w!j dUaleslni your est Wrlta today. RICHARD B.OWEN.Patant Lawya. 92 Owaa Bulldlas. Wuklastte. D. O. 2276-P Watlvertk Bids.. Htm Tart Olty Radio World, 52 ia Subscribe direct or through rosar arwi deader. $6.00 a year, $3.00 an months, $130 three months. Ratio World, 1493 Broadway, N. Y. C Government Broadcasts Educational Data Twice a Week To reach the general public, as well as school workers, with educational informa- tion and to spread it promptly, cheaply and widely, the United States Bureau of Educa- tion sends out messages twice a week from NAA, the naval aircraft station at Radio, near Arlington, Va., on a wave length of 700 meters, says the New York Times. The messages are sent on Monday and Thursday evenings from 6:45 to 7 o'clock. The first of the radio talks was given on Dec. 7, the subject being the economic loss due to illiteracy. Later messages dis- cussed the money value of education, visual aids to education, the necessity of education in a democracy, the work of the Bureau of Education in Alaska and the shortage of school buildings; "The Bureau of Education has started this service because it is the duty of the bureau to reach not only technical experts but also the general public," says the announcement of the innovation, "and it is the opinion of Dr. John J. Tigert, United States Commis- sioner of Education, that the public can be reached more quickly and directly by radio than in any other way. "Radio has the advantage of intimate con- tact between speaker and audience, and since the bureau's messages will be sent on a regular schedule, they will have the con- tinuity necessary for informing the public on educational matters. Since public edu- cation cannot progress any faster than the state of public opinion about education, the Commissioner believes that the in- auguration of the radio is an important step in advance. Newspapers in California and Washington have requested permission to broadcast the bureau's messages to the Pacific Coast States, since the Anacostia radio reaches only to the Mississippi River. "Such subjects as the combating of illiter- acy, the consolidation of rural schools, health work in the schools and Americanization will probably be taken up in future mes- sage. Those hearing the talks are urged to write to the Commissioner of Education and to comment on the material presented and upon its form. Tell him whether you de- rived any benefit." Reaching 8,000,000 People CARRYING on educational propaganda among people who are working all day long and cannot attend university classes, is one of the great uses of radio, according to Prof. Michael I. Pupin in New York "Evening Post." Think of the potential audience within listening distance of Colum- bia University by radio. There are 8,000,- 000 people within a radius of fifty miles: You can reach them by radio with the simplest and most direct medium of com- munication, the spoken, the living word! Think of what it would have meant to St. Paul if he had had such a medium of communication. Then, while he traveled from Jerusalem to Cyprus, Caesarea, Corinth, Ephesus, Fhilippi, Thessalonica, Athens, and Rome, he could have sent the words of his mouth to all the churches every day. Those marvelous epistles would have been given a most powerful reinforcement. We need St. Pauls in our universities to- day—men who will rise up and preach the doctrine of truth and democracy. People who work all day, people who will not leave their homes to attend a lecture course, people who tire of reading the dry printed word, will listen if all they have to do is to use a radio. There are millions of peo- ple who are thirsty for knowledge whom we could not reach by the old methods. The singing of carols in the U. S. was distinctly heard by an Aberystwyth wireless amateur. Nevertheless, nothing daunted, he proposes to continue with his hobby. — Lon- don Opinion. Pictures and intimate gossip of some of the entertainers you hear via radio. ARE YOU INTERESTED in F00TLIGHT NEWS AND GOSSIP? If you want to keep posted on everything connected with the American stage read NEW YORK STAR $4.00 a year (52 issues) $2.00 Six months $1.50 Three months 10 cents a copy Trial Sub. Offer NEW YORK STAR 14*3 Broadway, N. Y. C Send New York Star to my address trial sub. for three months (thirteen issues) for the accompanying fl.00. Name Street No City and State I I: j GoOgk

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26 RADIO WORLD IF YOU ARE INTERESTED IN RADIO YOU NEED THESE BOOKS BEST RADIO BOOKS Telling How to Operate a Radio Set— How to Build a Set — Principles of Vacuum Tubes and Other Radio Problems Radio Hook-Up. By M. B. SLEEPER A book that gives you not only clear dia- grams for all kind* of telephone and tale- graph receiving and tranamitting acta, but simple descriptions of each circuit shown and spaces for notes of results obtained. PRICE TSc Construction of New TypcTrans- atlantic Receiving Sets By M. B. SLEEPER There is a peculiar fascination about re- ceiving radio messages from the high- power stations of England, France, Ger- many, Russia and Italy, as well as those located in the Pacific Ocean and the Orien- tal countries. Several types of simple re- ceiving sets for this purpose are described, with detectors and amplifiers to accompany them. Suggestions are also given for oper- ating relays and reproducing the signals on a phonograph. Schedules of operating time for high-powered stations are given. In addition, there is some valuable data on home-made wavemeters for testing and ex- perimenting .PRICE Tfc fas Wireless Telegraphy and Tele- phony Simply Explained By ALFRED P. MORGAN One of the most complete and comprehen- sive treatises on the subject ever published. A study of its pages will enable one to master all the details of the wireless trans- mission of messages. The author explains in simple language the theory and practice of wireless telegraphy and telephony. 154 pages, 156 engravings PRICE flJH Design Data for Radio Transmitters and Receivers! By M. B. SLEEPER The only book that gives tables and data for designing, receiving and tranamitting apparatus so that you need no knowledge of mathematics. It's the first book a be- ginner buys after be has learned the use of his phone receiver PRlCE_JScu Construction of Radiophone and Telegraph Receivers for Beginner By M. B. SLEEPER The man who wants to feel the real thrill of accomplishment, and who is not satisfied in the merely making use of what others have done for him, builds his own radio apparatus. Radio men can follow the data in "Radio Phone and Telegraph Receivers" with full confidence, because each piece of apparatus described was first made, tested and found efficient before the final design waa accepted. Special receivers, both crys- tal and audion, are shown in detail Regen- erative circuits as well as audio and radio frequency amplifiers are described with clear photos, diagrams, and working draw- ings prepared especially for the novice and the man who wants to receive the radio telephone broadcast. A special feature is the phonograph type radio set and the loud speaker. Fully Illustrated .PRICE 75c. The Radio Experimenter's Hand- book By M. B. SLEEPER Throughout the preparation of this book, one purpose waa kept in mind— Answer the Practical Questions of the "Novice," of the "Beginner7' and the more advanced "Stu- dent." This book will help in the selection or construction of simple apparatus for the transmission and reception of radio tele- graph and telephone signals. In the chap- ters on radio receivers the simplest crystal, the simple audion, and the regenerative types are described in quite some detail. The question of antennas, both for trans- mitting and receiving, are taken up. A good many helpful suggestions are given which will be of considerable aid to the experi- menter. 16 chapters. Fully illustrated. PRICE tl.tO The A B C of Vacuum Tubes Used in Radio Reception By E. H. LEWIS Assoc. I. R, E., and Radio Instructor Written particularly for the person who "knows nothing about radio," but who would like to gain an understanding of the elementary principles of operation of vac- uum tubes and various circuits in which they are used for the reception of radio- telegraph signals and radio- telephone music and speech. Illustrated PRICE tLM Books on Electricity ArlthSMtle *f Electricity. By PROF. T. O-CONOB SLOAN* A practical traatlM on electrical calculations «f an kinds re- duced to s Mrles of mica, all of the simplest farms, end knowing only ordinary arithmetic; sash tola Illustrated by ees or more practical problems with detailed eolation of seen one. This book la classed among the most useful works published on the selenoo of eleetrlelty. covering ss It dsas the mauunatles of eleotrldty la a manner that win attract the attention of those whs are net rami liar with slnbndesl formulas. 100 paces. Now Se- nsed end Enlarged Edition. pries, II.5S Coaautater Oeaati uclloa. By WILLIAM BAXTER. JR. Tbc budnaae end of dynamo or motor of the direct earns* Bps Is the commutator. This book gees Into the dselfn- lnff. building* and maintenance of ocean shows bow to locate troubles and hew to them; ereryone who fusses with dysasm. . this. Fifth edition. Price. II Dynamos ssd Electric Motors and All Abort Them Br EDWARD TMVeTRT. This prentice] direction for building a two . (Vies a P. byname of tbc Bdlasa typo capable ef Hit _ about nfly msdss lamps of the SO-watt sine. la addition. It gins directions for talk-Bag two swan eleeUle motors suitable far running sewing ma- efalnea. The oandudlng chapter daacrlnaa the con- struction of a el tuple bichromate battery adapted for running electric meter*. 01 pages, ruttr Illustrated with detail drawings, data. Pries. 11.00 Dyasae BulMIno for Aetata Bra, or Hew ts Oca- struct a Fifty Watt D yearn. By ABTHUB J. WEED. A tmoUaal treatise showing la detail the construction of s email dynamo or motor, the entire B*"**'1t work of which osa be done on assail foot lathe. Duaea- elaned working drawings are glean for each piece ef machine work, and each operation Is dearly desert bed. This machine, when need as S dynamo, has sn output of flfty watts; when need ss s motor It win arras a small drill press or laths. It sen be used to drive a sowing asehlas ea any and all ordinary work. The book Is Illus- trated with more than sixty original sngrarlngs showing the actual eonstrustlsn ef the different parts. Price. 11.00 C Any of Thee* Books Sent Prepaid on Roeotnt sxf Pi Una. The 11 Book* for SltM, to One or Different , address THE COLUMBIA PRINT ROOM 326. NO. 1493 BROADWAY, NEW YORK Digitized by Google

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RADIO WORLD ExooUeat 43 Piatt Condenser .001 $1.38 ExNltMt .0005 VarlaoU Omfcnisr I. is Varlomstsro. Baldwls Styll. Wood 1.50 Kim AaiplttMt LMd Tslliera 4 JO Fiut-Cu-LMm Multlshsess 2.00 CASH WITH ORDER Radio Engineering Co. 2 Wast 28th Street New York City Mr. Dealer: We an Job ben for Framlngham Plain and Vernier Rheostats; Klosners new and old type Rheostats; Seranton Button Diala 1-lnoh and 8-lnofa. and imitation 3 - Inch Electrons Dials. Write for quotations IMPORT NOVELTY CO, INC 147 Wett 23rd Brest. Ne* Vera City, N. Y. Quality Radio Products istearaph llosdoill and Loads peak en CottlM A Wasfelnstoa Radio Sots Uehwoal 3 Plats Vernier, 23 and 43 Plats Osadsaosrs, Radio t tores • Batteries Jebkers and Dealers: Writs sr Wire For tke Blasstt Prosotmon la Radio. Frederick H. Pruden Incorporated Baiidlas J sresy City, N. J. GALENA CRYSTAL mounted in specially prepared metal 30c. Unmounted 25c. All guaran- teed. Manufacturers, Dealers and Jobbers write for quantity prices. We also manufacture Radio Parts to order Precision Tool & Mfg. Co. 102 Lewis Street, New York ■ ■■■■■■ I SURPRISED? Vr^REP/JR VACUUM TUBES Detectors KMIaCO Anplifjers^ w Vow dealer skest* kaow. sat It as doss sot eead Street t* HARVARD RADIO LABORATORIES Boston I, Mas*, Takes retaraod Panel Poet 0.8. D. Radiate Your Home List Our Price 18.00 Federal Phones 30.25 1.90 KJosner Vernier Rheosuts .90 1.75 Bright Star "B" Bst- terles, 22 3 'olt 1.15 7.70 43 Plate Vernier Con- denser 5.00 6.60 23 Plate Vernier Con- denser 4.50 5.00 WD-11 Tranaformer 8.75 1.00 WD-11 Socket 50 60.00 Cuttlni! Washington Be- generaUro Tube Set 27.50 4.75 Variable Condenser 43 g ^ Write for free catalogue. Perfection Pays Parcel Pest Perfection Radio Corp of America Broadcast Coast Guard Stones WHEN the Coast Guard has good stories of life saving at sea to tell, they are broadcast by radio Tuesday and Thursday evenings, from N'AA on 710 meters. This ultra-modern method of keeping the general public informed as to Coast Guard activ- ities has proved so popular that it is rumored the scrapping of the typewriters and mimeo- graphs at the Bureau, used for press items, is being considered. Recently a broadcast from Uncle Sam's sea protectors reached one of his own outlying stations at Manitou Island in northern Michigan, as well as sev- eral of his cutters on duty at sea. The ninth story on Patrol of Regattas and the tenth on a shipwreck rescue were trans- mitted last week. Banneker Radio Club of Maryland a New One 535 Presstman Street, Baltimore, Md. January 28, 1923. Dear Sirs: I am forwarding you the names of our present officers. Roland Carrington, president ; Clarence Fax, vice-president; Tecumseh Wood- land, secretary; Ralph Reckling, treas- urer; John Hebron, chairman of execu- tive committee. Yours truly, R. CARRINGTON, President. Manager Keeps Track of Theatre While on Ocean WHILE S. L. Rothafel, manager of the big Capitol Theatre, New York City, was on the high' seas last week, bound for England, he was able to keep in touch with the program at the Capitol Theatre by means of the radio which was installed in his stateroom on board the Berengaria. A wireless report from the liner reports that he is receiving the music which is being broadcast direct from the theatre through the American Telephone and Telegraph station, WEAF. Why Not Try It? Editor, Radio World: If somebody wants to try something that will make him so excited he can't sleep nights, let him try the hook-up described in Radio World, page 19 of the issue of December 23, and make the fol- lowing changes. Put in a grid leak of about 1 megohm and a condenser of .0005 mf. Then take the phone condenser out and throw it away. Put in a WD-11 tube and a pair of Brandes 2000 ohm phones. Then take the old storage battery and give it to somebody, because you won't need h any more as long as you live. Hook up a dry cell in its place and that's all. Then sit down and turn the rheostat about half way on, twist the variable condenser dial around until you hear something that sounds like the stock yards, adjust the tickler and the rheostat, and oh, boy I Another bug added to the list!— A READER. Cannot Make It Too Strong THE minister of our church gave us a little talk the other evening at the meeting of the Ladies' Society, on the way in which radio has helped the human race in general. After the meeting our pas- tor apoealed to me, asking me if he had made his point strong enough or if I thought it was too strong. I thought it was just wonderful, as did all the others. You simply cannot make anything that relates to radio too strong. AMATEUR*. UNO FOR QATALOfiUE "B" Batteries That Last For Five Years RADIO EQUIPMENT MFG. CO. Dept. "B," 1663 Jsreee Ave., No* York. N. Y. -"B" BATTERIES- 22V4 Volt, Small $0.65 22% Volt, Large 1.85 22% Volt, Medium 1.10 45 Volt, Medium 2.25 No More Tubes at Bargain Prices Out of Tasks Dials Those Having Ordered Will Be Shipped Next Week DAFllsfn DISTRIBUTING & IyAIsIvJ auto supply co. 64 WEST 66th ST. NEW YORK CITY Pease Celiiaous 8584 See AdV. Next Week's RADIO WORLD REAL HADIO BARGAIN Murdock Condensers 23 Plate Var. (list $3.2S) $1.65 43 Plate Var. (list $475) 2.55 W. D. 11 Socket 49 Variable Grid Leaks 69 Rheostats — Acme 69 Murdock Crystal Seta- Complete with 3000 Ohm Phone, Aerial, etc 6.98 Acme 2-Step Amplifier (list $35.00) 19.75 3-inch Dials 19 Phones German $3.25 French 4000 Ohm 6.75 Murdock 3000 Ohm 4.25 Brandes— Superior 6.65 Dictograph 5.95 ECLIP5E RADIO C 4l4-\X/-4-1^JST. N.Y.C American Radie^tores TUBE SET 1 Rheostat 1 W. D. 11 Socket I W. D. 11 Tube 1 Grid Leak Condenser I "B" Battery, 2Z*4 volts 1 "A" Battery, dry cell 1 Variocoupler 1 "3" Plats Condenoer Wire for Hook Up Free I Panel, 7%*H% «>| r Cn Hook-Up Only Given with Set SIS. 5 V Complete Crystal Set Complete, tested. List SUts). Special $7.56 Federal Set with Phones, tested, List $25.00, Special IMS LOUD SPEAKERS Western Electric, Complete 8161.06 Mafnavox Paths Jclley Phone Woodehorn 7JS VARIOMETERS Baldwin $4.68 Emco Moulded 6.66 Queens tSt VARIOCOUPLERS Emco ISC tS.68 Baldwin tf J.7S Qu»ena 8T 3.88 R. M. C, 188-688 Jj* All Wars (Capital) 7.88 Multi-Wave (Cardweu) 7.88 American Radio Stores 235 Fulton Street, New York City „ Al, order, must include posted

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28 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? DEPARTMENT AT So A WORD TRY THIS RADIO WORLD S QUICK-ACTION CLASSIFIED ADS Advertisers will get a ten-day serviee here — that U, copy received for this department will appear in RADIO WORLD ; after copy reaches as. This department is intended for everybody who wants quick action on short announcements covering the baring, selling exchanging or general merchandising in the radio field. Readers of RADIO WORLD whl find that it pays to read these columns every week. ' ' ' """ " " "~ - - on the news-stands tea days i The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is 5c. per word (minimum of 10 including address), 10% discount for 4 tone— lira insertions, 15% for 13 consecutive insertions (3 months). Changes will be mads in standing classified ads. if copy is received at thia office ten days before publication. RADIO WORLD CO, 1493 Broadway. N. Y. C (Phone, Bryant 4796). BATTERIES— Edi son Storage "B" Battery Elements, 5c per pair; 18 will make one 22.5 volt Battery. GILMAN'S BATTERY SHOP, Chelsea Sq., Chelsea, Mass. ADVERTISING SOLICITORS to represent RADIO WORLD. The best quick action radio advertising medium. State territory you can cover. Tell us about your past experience. Write Fred S. Clark, Manager, RADIO WORLD, 1493 Broadway, New York. VACUUM TUBE RESULTS WITH A CRY- STAL SET1 Cover distance with a "PT" ULTRA- SENSITIVE CONTACT in your crystal detect- or. Beats gold and other ordinary catwhiskers. DOES NOT JAR OUT. Myrle Wood, Rhindand- er, Wisconsin, writes: "That *PT* Ultra-Senai- tive Crystal Detector Contact I purchased ia sure a wonder. Using the 'PT* contact and galena, I have heard over 43 different broadcast- ing stations, up to 1,10s miles distant" The "PT" has received code 3,300 miles. Price, only twenty-five cents. "PT" CRYSTAL CONTACT COMPANY, Box 1641, Boston. VARIOMETERS, $1.50 each. These are regular 4)4 -inch square variometers. ' Couplers, $1.00 each. Both usually sell at three times the price. THE RADIO SHOP, 361 East Broadway, MUford, Conn. PHONES, TRANSFORMERS REWOUND. L Werts, 409 Saint Julian St., Pekin, RL EXCHANGE LETTERS with friends everywhere Pleasant pastime. Information for stamp. Smith, Box 3HS, M. Portland, Ore. AMATEURS-LOOK! Send in 15 cento to RADIO WORLD for issue of January 20 con- taining panel layout, hookup and full explanatory data on the construction of a D-X receiver, which simply lays the long distance on your table. Or start your snb. with that isssue. RADIO WORLD, 1493 Broadway. New York City. MODEL MAKING— By Raymond Francis Yates. A new book for the mechanic and model maker. This is the first book of its kind to be published in this country, and all those interested in modal engineering should have a copy. The first eight chapters are devoted to each subjects as Silver Soldering. Heat Treatment of Steel, Lathe Work, Pattern Making, Grinding, etc The remaining twenty-four chapters describe the construction of various models such as rapid fire naval guns, speed boats, model steam engines, turbines, etc 400 pages. 301 illustrations. Price, 13.00. The Columbia Print, 1493 Broadway, New York City. STANDARD ELECTRICAL DICTIONARY— By Pro!. T. 0*Conor Sloane. Just issued an en- tirely new edition brought up to date and greatly enlarged— as a reference book thia work is beyond comparison, as it contains over 700 pages, nearly 500 illustrations, and definitions of about 6,000 distinct words, terms and phrases. The defini- tions are terse and concise and include every term ufed ia electrical science. 767 pages, 477 illustrations. (See page 18 for fuller description.) Price, $5.08. The Columbia Print, 1493 Broadway, New York City. PATENTS— Inventors should write for Free Guide Books snd Record of Invention Blank be- fore disclosing invention. Send model or sketch of your invention for our Free opinion of its patentable nature. Radio, Electrical, Chemical, Mechanical and Trade-Mark experts. VICTOR J. EVANS * CO., 924 Ninth, Washington, D. C OLD MONEY WANTED— $2.09 to $508.00 BACH paid for hundreds of Old and Odd Colas. Keen all old money. Send 10 cents for New Illustrated Coin Value Book, 4a*. You may have valuable coins. Get posted. We par CASH. Clarke Cain Company, Ave. S3, La Roy, N. Y. STUCK T— Let me problems. Service _ •rick Barber, He Jasper n solve your Radio reoolving jasper at*, Syracuse, n. x. HAVE YOU SEEN ITT My unusual fully il- lustrated radio catalog is complete. Only a dime. N. E. Ristey, Spring Grove, Minnesota. RADIO TUNING RODS (Patent Applied For) Eliminates body capacity when tuning in. With Tuning Rod in your hand you can stop unnecessary noises and shrieking. Every radio fan should have Radio Tuning Rod. Send 15 cents stamps or money order. Radiophona Co., 505 Fifth Avenue, New York City. EXCHANGE JOLLY, INTERESTING LET- TERS through our club. Stamp appreciated. Betty Lee, Inc. 4254 Broadway, New York City. CASH FOR OLD GOLD, Platinum, Silver. Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth, Magneto Points, Jobs, Any Valuables. Mail in today. Cash sent, return mail. Goods returned in ten days if you're not satisfied. OHIO SMELTING CO.. 337 Hip- podrome Bldg., Cleveland, Ohio. ATTENTION. Amateurs II Have you seen the RADIO WORLD'S page of hook-ups in the Oct. 21 issue? 15c a copy or start your subscription with that Number. Many people are writing in for the hook-ups listed here. RADIO WORLD, 14S3 Broadway, New York City MILLION POINT TESTED CRYSTALS— Mounted in Woods Metal. These Adbria Crystals are tested and are guaranteed or money refunded. With so many sensitive points, it is impossible to miss contact. Stop wasting time and send us 30c for one Adbrin Crystal or send $1.59 for six, mailed prepaid. Also write us for information as we have other styles, including our new type combination twin Galena and Rariacitc Diolite Radio Panel Boards, insulated, rubber base, cut, bored sad drilled with ordinary toots without spoilage. Sizes can be furnished cut to your re- quirements up to 22x21x3/16. Write to us for prices or ask your dealer. DIOLITE IN- SULATOR CORPORATION, 287 New York Ave- nue, Brooklyn, New York. A COURSE IN MECHANICAL DRAWING- By Louis Rouillion. The author has written a most practical book on the subject of Mechanical Drafting. It fully explains the art of Drawing, Lettering and Dimensioning. It is, by far, the most practical book ever published on this sub- ject, tor use in day and evening schools, and more especially adapted for the teacher and for self instruction. Fifteenth edition, revised and enlarged. Fully illustrated. Oblong. COLUMBIA PRINT, 1493 Broadway, N. Y. C. Price, $LMl RAND-McNALLY RADIO MAP OF UNITED STATES— Is 28 x 30 inches in size. The locations of broadcasting stations sre shown by distinc- tive symbols. The call letters of each station are given, also the wave lengths of each. The Radio Districts with numbers are shown in red and the Radio Relay Divisions are in blue. Time zones are included. Alphabetical lists of stations and alphabetical lists of call letters are in the margins. Convenient pocket form with cover. Price, 35c. The Columbia Print, 1493 Broadway, New York City. BROADCASTING MAP of the United States appeared in RADIO WORLD No. 8. Sent on receipt of 15c, coin or stamps; or •tart your subscription from that number (${.00 for 52 issues). RADIO WORLD, 14S3 Broadway. New York SKND r/8 THE NAME OF YOUR RADIO CLUB Also the names of your president and other officers. We want to add these to radio clubs and officers we are preparing for publication In an early Issue. WORLD. 14» t Broadway. Now York. i list of RADIO POCKET RADIO SET Talk of New York Radio Show. Super-fine crystal. Patented tuning coil. Just the thing for hikes, bicycle trips, etc Send $1.00, cash or M. O. J. DEMLER, 121 Sherman Ave, N. Y. C MAKE MONEY silvering mirrors, all kinds plating, knives, spoons, auto headlights. Outfits furnished. Free booklet. International Labora- tories, Dept. 310, 311 Fifth Ave., New York. ASTONISHING RESULTS, ROKAY SINGLE CONTROL HOOK-UP. Don't buy, build or change your receiver until you get particulars. ROKAY ELECTRIC COMPANY, INGOMAR, OHIO. MAKE MONEY AT HOME MAKING TOYS and novelties. Send 5c for samples and particu- lars. New Specialty Co., 417 E. 71st St.. New York. RADIO BUILDERS AND BUYERS I Send 50c for (1) Any hook-up or diagram to meet your spccial needs- (2) Any special or general in- formation in answer to your questions. R. F. CHASE, 29 Bradlee St., Dorchester, Mass. NEWS AND GOSSIP OF THE STAGE— Send 10c for specimen copy of NEW YORK STAR, the great illustrated theatrical weekly. $449 year, $2.00 six months, $L00 three months. New tork Star Co., 1493 Broadway, N. Y. SUPER -SIMPLCITY CIRCUIT Hear Europe, Asia, Africa and Australia's long wave stations and LOCAL broadcasting, on ONE TUBE, one control. NO rheostats, storage bat- tery, variocouplers, variometers, three-coD mounting, variable inductance, taps, switches, dead end losses or radio frequency. Cuts, hookup, everything. Nothing to guess about. Price SLOB. RADIO EXPERIMENTAL LABORATORY. Box 194A, Berkeley. California. TWENTIETH CENTURY BOOK OF RECIPES. FORMULAS AND PROCESSES— Edited by Card " ~ i the i ner D. Hiscox. This book of 800 pages i complete book of recipes ever published, giv _ thousands of recipes for the manufacture of valu- able articles for every-day use. Hints, helps, practical ideas and secret processes are revealed within its pages. It covers every branch of the useful arts and tells thousands of ways of making money and is just the book everyone should have at his command. The pages are filled with mat- ters of intense interest and immeasurable prac- tical value to the photographer, the perfumer, the painter, the manufacturer of glues, pastes, cements and mucilages, the physician, the drug- gist, the electrician, the dentist, the engineer, the foundryman, the machinist, the potter, the tanner, the confectioner, the chiropodist, the man- ufacturer of chemical novelties and toilet prep- arations, the dyer, the deetroplater, the anasxelet. the engraver, the glass worker, the gold-beater, the watchmaker, the jeweler, the ink manufac- turer, the optician, the farmer, the dairyman, the paper maker, the metal worker, the soap maker and the technologist in general. A book to which you may turn with confidence that you will find what you are looking for. A mine of information up-to-date in every respect. Contains an im mouse number of formulas that everyone ought to have that are not found in any other work. New edition. 807 octavo pages. Cloth binding Price, $4.00. The Columbia Print, 1493 Broadway. New York City. Radio World, 52 issues, $0.00. Subscribe direct or through yoar news dealer. $6.00 a year, $3.60 six months, $1.50 three months. World, 1493 Broadway, N. Y. C Digitized by Google

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RADIO WORLD 29 PATENTS promptly procured. Trad* Mark* retitured la the V. tV and abroad. Call or write. FREE ADVICE. Phono, TaodarbUt Ttlt. RADIO MAILING LISTS 12.400 Radio Dealer*, eteerlte u. «. ky Statae, ^ |( I.OlTRadie 'MrrL otw'iWt U.S." W Settae.' jrtr iiati'tllloo 1.757 Madia So eery jekkera, eotarlao U. t. ky State*, jar Mot .7. fll.M 1*0 Radio Statleat. par Hot 14.00 »S7 Mfr*. ate ■take tad oaauakie iiapiie* Radio tots, aor Hot I4.M XS.OM Radio AiMtonrt aad Maaeatn of Radio III W. ADAMS STREET OHIOASO. ILL. MULTIPOINT (Patant Ptndlnf) A Synthetic CRYSTAL DETECTOR Ellmlnaua all dMaaur trouble*. Xstrurilirury elearneet ud rolumo. Endorted by ratllo eipert* and pret*. SWd In mated peektaee only. Join tho erer-lncreatlnf Buoonlte fana Prtte, peoteald. ornated CA. Stttltimaott guamtatd **v RUSONITE CATWHI3KER 14-Karat Bold Multiple etetaet. OC, Suet repetitive £•)*> Or dor from your dealer or direct from ua Raoaalta Prodwrtt Corp.. II Part Row. N. V. f TIIEfGOODMAN 1 Tho NtftJaat Short Wave T« Only mM A PP 001 1 Ik. i L. W. GOODMAN DREXEL HIEL, PA Dorter . Nerrlttew*. Pa., la try alt* aor SOODMAN, km art Me 10 ejlleo eel treoi San f DENVER keard a tola*. "Wo ■ Fraeeltet." Thee la and teak tke oklp. Ift the contact that counts The special paaatphot broate cllee W tke H* aid W. D. 11 Socket aantntarn perfect content rnMnrdlnna of any raria Mm In tnkc prongi and baeea. Moulded from gen aha* Condenaite. theae eockete arc made for wee with the faraoua W. D. 11 take*, operated by a tingle cell battery. The Na ald De Lose V. T. Socket it of higheet quality througheat. Ita laminated pa ettkof bronte it riot prea* irmly with a tide wipe actios ya the contact pint, keep- ing turf ace clean aad fea- turing perfect contact. Th— aocAvr* rut mil at 75c much Send stamp for dial, imall-epace eocket, con- d enter and R. F. Trana- former circular*. AMOR MeaRRNMlaliRg OS. ffereterry ALDEN-NAPIER CO. Oeet. L 52 Willow SL SerlefOeld. Mete. RADIO WORLD TaTLnTBOltn. BBTAMT 4t*0 TSeTT WIUIMDiT oUTPa\PAT Of BAMB WMMK) rmoM puBUCano* ormca, 14*0 MOAVWAT. aTeTW TOeUL. M,_T BY MMKTtmmi RADIO ~ ROLAND BTJBJU at. a. wen a rf -*ww 14*1 uaiDwiT. iraw TOnX. X. T. TECHNICAL EDITOR L sumacRirnoH rates a*j a eanr. 10.00 a rear. SUM I tLMtet tkaat i ADVERTISING RATES One pane: One Meat 1100.00. Bait. Tern 10 dapa Mat I* 10 CLASSIFIER A»' Pi to rount of 10% ea 4 IS. iota. IMPORTANT NOTICE every II ae retard for cat net-eaiMlrfy far ef peltate, arltatty of em ef tHttloal en be pruned a* turatorwd ky Thlt omental la tie*? tad eaal If Your Regenerative Receiver Won't Oscillate Under the heading "Not in the Text Books," a writer in the New York "Mail" gives the following "tips": "If your regenerative receiver doesn't oscillate there are several possibilities to investigate. The grid leak should be varied either by the insertion of tubular leaks of various resistances or by the addition or erasure of pencil lines between the grid condenser terminals. The phones or the first amplifying transformer primary should be shunted by a fixed condenser of about .001 mfds. capacity. Tickler leads should be reversed. Also the "A" battery leads should be changed around, aj de- tector tubes sometimes arc improved in their operation in this way. "A leaky socket is a very common cause of this trouble, too. A socket hav- ing a few thousand ohms resistance be- tween terminals will prevent a circuit from oscillating. High resistance joints in the circuits through which sufficient cur- rent might pass to give fairly good signals will sometimes prevent regeneration. Hence all pressure contacts should be thoroughly cleaned with sandpaper and all other joints soldered." President Tries It Out President Harding is said to have tried out his radio set for the first time during his recent illness, without satisfactory results. He succeeded in getting a local station and one in Newark at the same time, but, being unabV to disentangle what sounded :ike a conference report, he gave up. RADIO PANELS Hlsk dMottrle rteleuatt. r»aS4" S"»t4" 11"»S4" Lit Mtaetattarort- oaatlel el tat lei letted. Asoatt treated. PAGESON COMPANY ■ea 00. Mertkaatt StttJee. St Leato. Me. RADIO PANELS C*teraeth> la Mat aad ektpped wltble It beam H, »•» taeek. l*i par to ten lath. 1/10 ma*. WILEY PANEL CO. SttS So. Oaatral Park Ate, Oat ami, in. RADIO TOOL SET wit* Itldorlaa irea wist U>ea»a3oTWoi CEB CO, IN Park Plaaa, Now Tan* FREE 8HELTONE LOUD 8PEAEER pair ef At tlSjM > etae. atearaoat aad daatan. Cash with order or C. O. D. WALTER SCOTT 10 St. Laaaa Pleat Novo NOTE THE INSULATKD BINDINC POSTS AND 7iw WIRE COWWrCTOR NOVO M'F'G CO .•4J4 W JJ;s»r W SO DCARaoax 3T e*^e*B*BTe*B*m*BTe*e**aTe*mm GITHENS TRUTONB RADIO HORN— LOUD SPEAKER First one to orll on tea day trial Moaey hack Retail Plica RUN Included Load Speaker Ttaaoae bat beta ereaeeeaed tee ben ea net ettrfter Ip enena It bee e elear fee eheeld try Till ell aad If Tor dee' I Bad Tieloao be rojwedod. ll le eald oa t lea day trtej If aat eerrled bp rear dealer erne ea Dtarr-ibeuors and Dealer t. writ* ! AUTO PARTS MFG. CO. Digitized by

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30 RADIO WORLD T.*oB««VAC-SfflELDS"«*»'« bring In DX The InTentian al tkii cuts oat . _ ie effect* between vacuum tubes, over- comes interstate coupling, which causes distortion and unnecessary noises which make it diffi- cult to tune in dis- tant stations — also guards tubes against breakage. Your tubes should have them. Attached in a minute // your dealer oannot supply you we will (hip immediately by mail pottpaid on re- ceipt of 11.00. ORANGE RESEARCH LAB. « North Uth Street East Orange, N. J. Difficult for Ordinary Set to Tune in NAA THE opening of the powerful Arlington station as a broadcasting station should be of considerably more than passing inter- est to the millions of radio fans, says the New York Globe. No broadcasting organ- ization has the facilities or the staff to com- pete with the government in the operation of a first class station. Whether the re- sults will be on a par with the possibilities will soon be known. But the opening of this station is at the same time a disappointment to many thou- sands whose sets will be incapable of reach- ing up to the wave length of 710 meters on which Arlington transmits. Many sets whose makers or sellers optimistically cred- ited them with an upper wave length limit of 800 meters will just about tune in NAA, but the short wave sets using variometer tuning in the plate circuit are quite certain to be far below the range. To load up a three circuit regenerative set is a task requiring patience and above all WALCON Radio Frequency Transformers Brings In distant stations on a loop— perfect reproduction. He .distortion. THE BEST YOU CAN BUT WALCON Transformers are tested and guaranteed, adapted for nee with W.D.11 tubes. Four new hook-ape. Inclodlng a new reflex circuit without charge with each transformer. Price, $4.00. We pay postage). Dealere and jobbere: Write for our attractive sales proposition, backed by national advertising. Manufactured by THE RADIO CENTRE, 2 W. Broadway, N.Y,N.Y. DELICATE SOLDERING Both the mnnafactarers' and amateurs' problem on all An •aired by the mttrnment constructed for this particular ■expose. THE POST SOLDERING IRON Platinum Heating Unit — Interchangeable Tips — Universal Current {.Large and Small) $6.00 Pram Tew Dealer or Write Awarded Certificate of Excellency. N. Y. Evening Mail Radio InstJtate POST ELECTRIC COMPANY, (DW. 509) 30 L 42nd St, New Terk inn pekilahed In BADIO Me. If NEEDED BY ALL AMATEURS I RADIO- WIRE TABLES, BY FKEDUUCK J. RUMFOKD, taklee. ibOTlns the Beater ef teat In a psead am fnwtloea a peond. as hllm: Ne 1— Enameled Masaet Wtn. BADIO WOBXD. Ne. 14, dated Net. II. Me. . — — — >end Wtn. RADIO WOULD, Ne. II, dated Nee. II. Ne I— Devble Oettee-Omrea Win. BADo* — , »•. II. deled Dee. J. Ne, 4— Stasis Silk-On end Wire. BADIO WORLD, Ne II. Deled Bee. IS. I Poubls SHk-Cerered Win. RADIO WORLD. No. «•. dated Dee. IS. Seat te ear eilih— sestpald et er uu eoeaplete eat et I espies rer fl easts. Or atari ram eubssrtptteo with ear asailar. bonder abeuld hen thaea uMaa eeoauatlr at hand. The mvtj et keek easseeea h) Untted. A DIO WORLD. 1491 BROADWAY. NEW YORK. N. Y. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK ' RADIO WORLD RADIO WORLD 1493 Broadway, New Yerk City. Please send me RADIO WORLD for months, for which please And enclosed $ SUBSCRIPTION RATES: Steele Coax 4 .11 Three Months LS0 Sx Months L00 Oae Year (52 T.*ues) 6.00 Add $100 - for Foreign Foster' iao Poet- else a spirit of research. The primary of the average set is well able to reach 710 meters, but the secondary and tickler cir- cuits must be loaded with additional induc- tances. Compact coils of the honeycomb or duolaterals type are probably best suited for this purpose. For the average fan to load a circuit means a makeshift set If the owner of aa outfit wishes to tune effectually to 710meten a triple coil mounting using compact odQi is the best arrangement The usual rano- coupler and variometers are then discon- nected and the three coils employed as pri- mary, tickler, and secondary, respectively. Limitless Possibilities IT APPEARS not to have been under- stood by all who have written about this new achievement of General Squier's, that the wire cable is used only to direct tbt "broadcast" message, as a telephone win directs ordinary line-radio conversation, sayi Dr. Henry Smith Williams in his new book, "Practical Radio." The electric-light wire is not functioning as an aerial. It does not catch up signals from the ether, but only conveys messages— lectures, music, or what not— sent directly from a transmitter in the power-house, the transmitting appa- ratus being connected to a socket, just at is the receiving apparatus at the other end of the line. It would appear that such use of an electric-light system offers at least one solu- tion of the broadcasting problem. To il- lustrate: In most village communities, the electric light goes everywhere. Concerts and other entertainments could, of course, be heard by line radio wherever the electric- light system is installed. Half a dozen different programs could be sent at the same time along the wire, by using different frequencies. It would thus be possible for each household to select the particular en- tertainment that it wished to hear. _ It would be possible, apparently, to have different entertainments in various rooms of the same house. Father could listen to the sporting news in, his study; mother to a concert in the sitting-room ; and the children to some juvenile entertainment in the play- room. Meantime, people whose houses are not supplied with electric lights might gather in various public halls, say school- rooms and churches, to listen to entertain- ments of various types. The possibilitiei of the method seem limitless. The College on the Hearth "The National Radio Chamber of Com- merce is developing a scheme to establish radio extension courses in American col- leges and universities."— News note. I've taken half a year of Greek, And studied that exacting Profession, 'til I've learned to speak Quite casually of acting. And, all the time, I've never had To go to school for knowledge; By radio I am a grad- uate of Broadcast College. BEAU BROADWAY— in New York "Telegraph" A Matter of Cost The reason that the super-heterodyne, sometimes called 'The Rolls-Royce of Radio," is not more popular is the same as for its big brother— 'The upkeep is too high." Broadcasting map. 15c That is, 1 complete broadcasting map appeared is Raoio World. No. & dated May 2a. Mailed on receipt ef 15c Radio World Company, 1493 Broadway, N. Y. C Digitized by Google

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RADIO WORLD Orange Label Tea Special TO? Tins Has a body to it that men like! For smacking flavor, delicacy of aroma and a cheerful invigorating influence, drink the best tea - Ridgways Tea. Also sold in 1 lb., Vz lb. and V4lb. TINS it Ridffwar*. K, N WiM St, N«w Ymk 'VtfVrrr ' GOLD MEDAL San Francisco 1911 uRAND PRIZE Sun Dn'Jo 1910 Digitized by Google

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RADIO WORLD R. U. INTERESTED IN RADIO? Radio is one year old now! What are its possibilities in another year? Over 1,500,000 Radio Receiving Sets are in daily use. Estimated daily radio audience is 10,000,000. What will the radio audience be, 5, 10, 20 years from to-day? TTPTTT? ADVERTISING T?"P17'I7 r JYH/H/ PRIZE CONTEST " JX.Il/ll/ FOR RADIO FANS FIRST PRIZE— $250.00 Radio Set Free Six Tube Radio-Audio Frequency Set SECOND PRIZE— $150.00 Radio Set Free Four Tube Set, Detector and 3 stages Amplification THIRD PRIZE— $100.00 Radio Set Free Three Tube Set, Detector and 2 stages Amplification To advertise our business we will give the above prizes to the three per- sons sending us a list of five or more names of Radio fans and who com- pose the best slogan or phrase of words we can use for our advertising matter. We are interested in sending our catalogue and price lists to Radio fans. If you are interested in Radio and in its future possibilities don't over- look this opportunity to get acquainted with us, secure low prices on your purchases and an opportunity to win one of the above prizes free of charge. In the event of two or more persons submitting the slogan fudged the best, second best, or third best, each will receive the full amount of the prize tied for. All entries must be received by us not later than March 31, 1923. We retail at wholesale prices. Lowest prices on standard radio goods in the U. S. A. National Radio Products Corporation 509 FIFTH AVENUE NEW YORK Google

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15c. a Copy February 24 $6.00 a Year 1 WORLD Hook-up for Building a Power Amplifier See Article Inside by C. White, Consulting Engineer A i A "Bat © © x_ X 5 OOtpvt Or P This diagram shows In a cfcmr and concise manatr how any on* can b iild bU own power aasphfier. Th* principle of a mmwm a— oliftor is that ths last two tubas, bvtnff hooked m paralloL can deliver mor* plats current and In a much smoother nanotr than several stafos mi iifihr audia frequency. To* transformer is of necessity of th* split secondary type, of which a full description Is f-iven In an inside article on the ewb>rct by C Whlto, Cotawhtoc Enffa*f ■ Ths tubas ussd In this amplifier must of necessity b* hard tubes, preferably of the power type, bscauas ©4 the fact that ths transfer of snsryy u) so f reet that war* an ordinary tuba used ths tubs would break down. Th* various choke coils nssd as tha circuit ar* nscassary to prevent any "baching -up" of th* currant front the second tub*. J

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RADIO WORLD Rexite Synthetic Crystals Seusitive over the entire surface. Price, including special catwhiiker, He. Dealer) — Write for unusual proposition. THE AIREX COMPANY 237 Csntre Street New York RADIO PANELS *"xM" U"*«4V' Hlok dlelestrle Anwti vasts*. PAGBSON COMPANY t. Msrskusts statles. St PARTS PRICES SLAUGHTERED 19.00 Ostsstsr Tubes, oust. $2.76 6.00 Aaslltsr Takes 1.10 0.50 flav. IV, aatslltsr) sails W. 0. II 4.M dry sail takes...... 4.11 Peeeas. seas sealtty, 1200 aiau 1.75 14.71 41 Parts Var laats Csadaatar $2.71 1.00 Rkeettet 10 1.(0 Ktssasr Vsralsr Was—tat 1. 10 1.00 1" Hard Rekeer aTlaJ .10 .00 V. T. Ssaksts 00 1.50 11* V- Otskas ■. Batteries I.71 »K V. anises B. Battsriss I. IB To stsM tlelajs shack liases and B. B. RADIO CO.. IM Meraaaid A' .00 OABH WITH ORDER PARCEL POST PRCPAIO 1 11.00 Klei Aaslltsaa Lsec ftsssker Haras »;.7» ,wtu,^^,l••••,M, 7.N All Wavs . asstsrs ...... 0.00 (.•• Vsrlsasotars t.7t Oasfcaaw ' * 1.7» 11 Plat* •sssesr 1.40 BKOOaTXTW. M. T. 71 1.11 DELICATE SOLDERING Both the numnfavetuvrt' and amateurs' problem on all fine work Is readily solved by the instrument oonatracted for this particajar parpose. THE POST SOLDERING IRON Platinum Heating Unit— Interchangeable Tips— Universal Current (Large ami Small) $6.00 From Your Dealer or Write Awarded Certificate of Excellency, N. Y. Evening Mall Radio Inttltete POST ELECTRIC COMPANY, (DtY 569) 30 E. 42nd St, New York -RADIO SHOF^ 161 GREENWICH ST 'Between Liberty &Grtla*ti NEW YORK CITY CLEARANCE SALE OF STANDARD SETS At More Than 50% REDUCTION Every Set Sold With a Money Back Guarantee If Not Up to Specifications $225.00 JOHN FIRTH 235R— 5-TUBE SET $112.50 This Set comprises 2 Steps of Radio Frequency, Detector and 2 Steps of Audio Frequency; a Firth V oca tone and Baldwin Type C Phone set in the Cabinet makes this set the finest and most compact on the market. The Regular Price on this Set is 1225.00. We are cutting this down to Can be used with indoor loop aerial. $125.00 JOHN FIRTH 23SA — 4- TUBE SET One Step Radio Detector and 2 Step Audio Frequency Amplification. Regular $125.00. Cut to $71.00 DE FOREST DETECTOR and 2 STEP (DT 700 and DT 800), $25.00 DE FOREST CRYSTAL SET (DT 000), WITH PHONES. $60.00 NOW $35.00 $12.50 $5.00 MULTI RADIO SCOPE. Makes it possible for five people to Bates fa ^ QQ on one crystal set. Phone Plus 35e 8. 9. Iseks 25e Arous Lightning Arrester 75e Vartsble Home .0005 Vernier .... Bakellte Varloeeupler Condenser with 52.95 $2.95 EVERY ARTICLE PURCHASEO FROM US CARRIES WITH IT AN UNQUALIFIED GUARANTEE THIS IS A PROTECTION NEVER BEFORE OFFERED THE PURCHASER WITH AS i uucu SINCERITY. OUR RECORD IS OUR BOND MAT* OF' V.ur Mail Or,ler« Bm»( the Same Careful Attention from Us. as You Yoursrlf .,,1.1 lU-cche Ov.-r Our -oumer. Our Mall Or.ler Department Work. Silent™ ™d ."" llemltunce lo Your OtUor ami Mall lu We Do I .Satisfaction la Our »osan. u RADIO At Cut Prices Standard part* only m original packing. Sold on a "money- back" basis. ■Reference "RADIO WOULD AdBSUbU Das- PHONES $11.00 Brown Phone, phrarm. Single Unit 14.05 5.50 Morotoek Phones Ml 0.00 Muslo Phones 1.50 11.00 Nathaniel Baldwin Type C. Desbes 0.05 0.04 Nathaniel Baldwin Type C. Stalls. 4.50 TUBES U. V. 100 1J.05 O. V. 101 4.05 V. V. 101-A I.H 1-H Velt SpeoUl 4,54 W. T. 501 Peanut t.H (Can be used on 3 dry aalls or < wit "A" sectary I CABINETS Made In oar factory 7" t 10" 7" I 11" 7" I 24" 51.05 2.05 1.05 MISCELLANEOUS 55.00 Multtrsdloseope (with this. 4 people can listen In on one bead set) DUBATEX Permanent Crystal Detector 17.50 Pioneer Moulded Tsiioojeter 8.00 Pioneer Moulded Varloeouplsr W.D.-ll Adapter $1.50 Llehuilng Arrester. Indoor end Outdoor Type Vurdoek Loud Speaker Horn with Pbene. . $5.00 Acme Transformer. Radio and A Mil. 5.50 — 180* Vsrloooupler on BakeUts BUk Wound Wire 8.00 Genuine ■Tuska" Molded Yarleaseter with Dial Ammeter for Testlnc *B" Batteries $5.00 43-Plsts Condenser 4.00 23-Plste Condenser 1-lnch Bskellts Dials 4 -Inch Electros Dials 3 -Inch Bakellte Dials W.D.-ll Transformer for W.D.-ll Tube $1.00 Freshman Variable Grid Leak and Condenser Combined Genuine All-Ware Coupler $10.00 — 3000 Meter Coupler $1.50 2.H 4.0$ 4M .15 .15 5.N 5.45 2.45 2.05 -41 1.05 .1.55 M .75 .35 4.(5 .80 7.00 4.05 WHEN ORDERING BY MAIL Add Postage by the f ollowing Seals PURCHASES I'p to $1.00 add l»r. •1.01 to »2.O0 " lie. 1.01 to 3.00. S.01 to 5.00. 6.01 to . 7.00. 7.01 to 10.00.. Money order < toe. Me. RADIO STORES Dept E. 1, 191 Fulton Street, N. Y. C NEW YORK'S GREATEST RADIO MAIL ORDER HOUSE D X Records are mads with 6000 Ohm N & K Phones (List pries $14.50) A hither ohmaee than any other pease Sale Price $7.75 For sale by all reliable dealers. Dealers, phone or writs far special prapasltlas. National Radio Distributing Csv (Dept. W) 51 West Itta Street Subscribe for RADIO ' Digftfar. $3.00 si?f RLD. f&OOo three mostbs '■■witawy,.

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VOLUME TWO OF RADIO WORLD (Zatered is sacood-cUas matter. March M, 1KJ. at (ha Poet Office at Mew York. It. T., the Act ef M area 3. U7M A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publication* Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4798. VoL II, No. 22. Whole No. 48 February 24, 1923 15c per copy, $6.00 a Minneapolis Man Perfects "Flivver" Radio Set Capable of Receiving Long Distances TIE trend of radio construction nowadays is toward the ex- tremely compact and practi- cal. This is demonstrated by the almost unlimited number now mak- ing their appearance. W. E. Foster, of 2308 Bryant Ave.. Minneapolis, Minn., came forward (C. Internalion.il New«rrrl> Mr. Faster, completing the connections on Us extremely simple and powerful little receivinf set. The complete set. not counting the better! #*. can easlljr bo carried In bis hand. This is said to bo the smallest practical working, long-range rubs sat m the country, and has established a ' of long distance receiving records. By Louis S. Fielder <t Internatuin.it Newtrerl) Exceedingly simple radio receivinf set designed by a Minneapolis man, circuit, and there is only one control, the condenser, and that used la of ana plate, with mercury as a second. It Is possible to Install this type of It utilises a single the type calling lor recently with an instrument con- structed by himself that is a most complete receiver. The whole in- strument, as can he seen by the il- lustrations, occupies Httie more space than is usually occupied by a socket and rheostat when mount- ed as a regular detector unit. The set consists of a single honeycomb with mounting, a rheostat, vacuum tube, variable condenser and grid leak. The size of the complete out- fit can be computed by comparing the instrument itself with the hand of Mr. Foster m the photograph on the lower left hand corner of this page. On a test it has been found to be an extremely sensitive and re- markably long distance receiver, and the fact that it has only one control tends to make it one of the simplest of its kind. How long be- fore .single control receivers will be the ones mostly used is merely a question of tune, as the general plan at present seems to be to simplify «-\er\ thing, cutting out unnecessary adjustments and everything that is n H absolutely necessary to the effi- cient working of the apparatus. Digitized by Google

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4 RADIO WORLD The Fundamentals of Reflex Circuits By W. S. Thompson, E. E. Department Electrical Engineering, Lehigh University BY REFLEX CIRCUITS we mean circuits in which the audion or triode vacuum tube is used for two purposes. That is, as a radio frequency amplifier and as an audio frequency amplifier. The reflex circuit should appeal to the radio enthusiast for several reasons. First, it should appeal to the "bug" who wishes to keep the expense connected with his-set down to a minimum, for it reduces initial expenditure and also up- keep, such as A battery charging and tube replacements. Again, it should appeal from the standpoint of quality of sound, for regeneration is not used and hence distortion due to that cause is eliminated. Also it allows the use of a crystal detector which gives a clear and full-toned rectifica- tion, bringing out all the harmonics which are so essential in all fine reproduction. To the semi-technical amateur it should appeal because it allows great DX work with an in- door loop without resorting to a ten tube set and because it is just another example of what can be accomplished with little apparatus. The Principle of Superposition The principle underlying the reflex circuit is the principle known in physics as "the principle of superposition." A general statement of this principle is scarcely possible, so we will illustrate every-day examples of superposition or where two or more effects are occurring at the same time and same place without interference. The vision of one person may cross the vision of another person without in- terference; two or more sounds travel through space and reach a person's ear and he is able to distinguish them ; and in general almost any effect in light, sound, electricity, mag- netism or heat may be superimposed upon each other with- out destroying the identity of either. Such is the case in reflex circuits where electrical waves of different frequencies are superimposed upon each other without interference, and without changing the quality of either wave. As a radio frequency amplifier the audion tube increases the amplitude of the wave picked up by fhe antennae or loop, until it is sufficient to be detected. The detector, either crystal or tube, changes the wave so it will cause sound waves if passed through a telephone receiver. pig. i. piy.mm.Hr. hookup of a reflex set, employing a crystal detector. By the use of this circuit, reception of atagals of an amplitude equal to one stage of radio frequency and one step of audio frequency U possible. A crystal detector la used. This does away with all tube noises, and makes a set of this type noteless and very clear in its reception. All marked in the diagram and should be followed. As an audio frequency amplifier the audion tube increases the amplitude of the electrical wave of audible frequency so as to cause a louder response in the telephone receiver. In the reflex circuits the wave picked up by the antennae is amplified by the audion tubes, detected by a tube or crystal and is again impressed upon the same amplifier tubes and is amplified as an audio frequency wave. Thus two waves are traveling through the amplifier tubes at the same time, one of radio frequency and one of audio fre- quency and neither of them interferes with the other. These two waves are superimposed upon each other and, due to the fact that their frequencies are totally different, they do not loose their identity. If they were both of nearly the same frequency there would be formed a beat note such as is formed in the regenerative circuits when the detector tube is oscillating. In the practical application of this circuit there are sev- eral difficulties that have to be overcome. The tubes have to be coupled for both radio and audio frequency amplifica- tion, but in placing an audio frequency amplifying trans- former in a circuit in which there are radio frequency waves, the windings of the transformer act as a choke coil through which the radio frequency waves cannot pass. This is overcome by shunting a condenser around both the primary and secondary windings of the audio frequency amplfying transformers, unless the secondary winding of the transformer has a sufficiently high distributed capacity so its impendence is low. Some of the transformers on the market today have a very low impendence in their sec- ondary windings in which case the by-pass condenser may be omitted around thig winding. The telephone receivers or loud speaker being placed in the plate circuit of one of the amplifying tubes would tend to act as a choke and hence must be shunted by a condenser. These by-pass condensers are extremely im- portant and no reflex circuit will function correctly unless these condensers are placed properly and are of the correct value. The coupling for radio frequency may be of several dif- ferent types. For the shorter wave lengths the coupling may be a choke coil, tuned impedence or radio frequency transformers. Practical circuits embodying these different types will be shown and each has its advantages. The author has not tried the reflex circuit on the higher wave lengths, but circuits embodying resistance coupling should be practical. Of all types of coupling used, the best for general use is the radio frequency transformer-coupled type. It eliminates a lot of complications and as there are in the market today several types of good transformers de- signed for specified wave lengths, there should be little trouble in using this type. The American manufactured tube is not especially adapted for radio frequency amplification, for it has a high internal capacity ; however, by using short leads and keeping wires from running close to each other and from running parallel to each other, this obstacle can be overcome. Re- generation should not be attempted except by the technical experimenter, for if the detector tube is oscillating it will paralyze the whole set and there will be no results what- soever, indicating that the tubes are choked. There is an- other limitation to this circuit; not more than two stages of audio frequency amplification can be successfully handled. This is due to the fact that the accumulative effect of more than two stages of amplification is so great that it would (Continued on next Page) Digitized by Google

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RADIO WORLD paralyze a tube so far as a radio frequency wave is con- cerned. That is, the change of potential of the grid would be so great, due to the heavy currents, a very weak radio frequency wave would be lost and have no appreciable effect. Crystal Detector Advantageous In experimenting the author has found that the use of a crystal detector is advantageous in many ways. The de- tector tube is noisy compared with the way a crystal rec- tifies. Those small parasitic noises when magnified by two stages of audio frequency amplification sound very loud indeed and hence the crystal is a noise eliminator. Another point in its favor is its cost and the fact that it is a distortionless detector. The threshold value of the crystal is higher than that of the tube, but the gain offsets the loss in signal strength. The use of the crystal for a detector also does away with the critical adjustment of the filament rheostat that is necessary when using the soft detector tube. This amounts to eliminating one very critical adjustment with is recommended, for the multi- control set is not a popular one. The author advises the use of a loop to pick up energy if more than one tube is used. The inherent noises in the air, so called atmospheric or static, will be greatly lessened if a loop or cofl antennae is used. The range using a loop is less than outdoor antennae but the directional properties of the loop cuts out interference and hence is to be rec- ommended. At best a reflex circuit is not as sharp in its tuning qualities as the tuned plate circuit regenerative sets; but by the use of a loop and good tuning arrange- ment this disadvantage is overcome. Until the operator becomes familiar with the peculiari- ties of tuning the reflex circuit the author recommends hooking up one tube set using a crystal or a two tube set using a tube detector. The author has given the constants that have given the best results, but conditions may alter them so a little experimenting would be well worth the time if only to get acquainted with the circuit. In radio frequency amplification the tubes function to their best advantage when the grid has a normal negative potential so potentiometers have been incorporated in all circuits in order to keep the grid at the proper operating potential. The potentiometer also acts as a stabilizer, for the tubes are "very apt to start oscillating. An added refinement that has not been shown in all hook-ups, is the use of a high variable resistance in the plate circuits of the am- plifying tubes. This weakens the strength of the signals to a slight extent but it serves as a check to prevent the tubes from oscillating, helping to overcome one of the bugbears for the novice. The tubes must not be allowed to oscillate, for oscillations will seriously interfere with the proper working of the set. A resistance, variable between 500 and 2,000 ohms, should be used, but a little experience in tuning will enable the operator to get the circuit to function without the use of these resistances. ff.f Fig. 2. Diagrammatic hookup of a reflex circuit, using a tube as the detector. This circuit is very selective, and by the us* of proper apparatus and careful adherence to the method of hooking up the instruments wonderful results can be obtained. Fig, J. Diagram of reflex circuit, using a crystal detector for the rectification of the currents. This circuit is harder to handle on account of the condenser shunted across the honeycomb, which is used as a radio frequency trans- former. This circuit can be operated on a loop by shunting the loop across the Local Conditions in Tinting As to the range of these sets there can be nothing definite stated because local conditions and skill in tuning will govern the distance covered. From Eastern Penn- sylvania the author has heard all the middle west stations better than with the popular one tube sets now in use, making use of a one tube set with crystal detector. The signal strength was not loud enough to operate a loud speaker but they came in clear, distortionless and free from qoises. As for other sets using three tubes the range will depend upon tuning ability of the operator, atmospheric conditions, use of loop or outdoor antennae and apparatus used, but truly remarkable results have been obtained using a loud speaker, although an external power am- plifier is recommended if sufficient volume to fill a hall or audiotrium is desired. Circuit No. 1 This is the circuit recommended for the person un- acquainted with the operation of reflex sets. The tuning is done with primary inductance and condenser and with the secondary condenser, which should have a vernier at- tachment. A vernier secondary condenser in all the cir- cuits given will help in avoiding inter-station interference, with the use of variable coupling between primary and secondary. By using the values given for the by-pass condensers satisfactory results can be expected. The use of the plate resistance is recommended but not neces- sary. An amplifier or hard tube must be used and the voltages on the plate will depend upon the apparatus used. The regular amplifier tubes U. V. 201, U. V. 201 A, etc., will stand 100 volts, but some audio frequency trans- formers will break down under this voltage, so 60 to 90 volts is recommended. The path of the signal will be traced for this simple circuit and will be sufficient to give user an idea of the practical application of the reflex circuit The antennae picks up the radio signal and the secondary circuit has a wave induced in it. This induced wave causes a change of potential of the grid and the plate current is varied ac- cordingly. The by-pass condenser around the receivers allows these high frequency variations to take place and as they are above audibility they do not affect the phone. The crystal circuit gets this amplified energy through the radio frequency transformer and rectifies the waves. The by-pass condenser around the primary of the audi fre- quency transformer allows radio frequency waves to be set up in this circuit. In the secondary of the audio fre- quency transformer there are induced electrical waves of audio frequency which are impressed upon the grid of the amplifier tube, which in turn controls the plate cur- (Continued on next page) Digitized by Google

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6 RADIO WORLD Micro- Variometer for Sharp Tuning By J. E. Anderson ALL radio fans who have worked with a highly selective receiving set know the difficulty of tuning in for greatest signal strength and of retaining it when once obtained. They find that the whole signal re- sponse from a particular broadcasting station lies within a single division of the tuning condenser, and that the slight- est movement of the dial to either side will completely obliterate the sound. All this is especially true of a regenerative receiver in connection with long distance work, and is a source of great annoyance when proper shielding and grounding have been neglected. The trouble is greater the smaller the effective capacity in the tuned circuit, and may partially be remedied by decreasing the size of the inductance coil and increasing the condenser value. However, this in- creases the selectivity and decreases the loudness of sig- nals, and the advantage is more theoretical than apparent. The practical solution will be found in some means of varying the natural wave-length of the tuned circuit very slowly. This is usually done either by means of a slow Constructional detail* of the micro- variometer aa explained in accompanjrfac tost. motion attachment to the rotor of the condenser, or by means of a vernier condenser in parallel with the main tuning condenser. But the same result may be accom- plished much more neatly with inductance variation at a cost that is negligible. I will describe here a little device that may be called the micro-variometer, with which final and exact tuning may be done no matter how selective the circuit may be. Referring to the diagram: R, R is a wooden dowel or fibre rod ^4-inch diameter of suitable length. "L" "ABCY" is a piece of heavy wire, or preferably 1/16-inch square copper rod, bent into the shape indicated. Near one end of the wooden rod, and on opposite sides, two grooves, (GG) are cut to admit the wire. When the loop has been put in place it is securely tied to the wooden dowel with okonite tape or some other insulating binder. The ends L", L', of the wire are bent up at right angles to the rod to facilitate soldering the connection leads to the loop. A wooden spacer W is attached to the rod either by means of a small brass pin or by a set screw. This is used to secure proper spacing between the panel and the tuning coil with which it is to be in mutual relationship. A small knob, K, may be used for turning the loop. In case a wooden dowel is used it should be thoroughly soaked in melted paraffine before use in order to prevent leakage. This loop is then connected in series with the main tuning coil in the selective circuit and so placed with respect to it that there will be mutual inductance be- tween them. If a tuning condenser is used to secure approximate resonance, the loop of the micro-variometer may be of such size and so placed that its entire variation of 180 degrees will represent a variation of 1 degree on that con- denser. A finer variation will hardly be necessary. If desired to have the micro-variometer cover a broader range, this may be done by increasing the diameter of the loop, increasing the number of turns, or increasing the coupling between the loop and the main inductance coil. A device such as has been described here may be used to advantage to obtain final tuning of a tapped inductance coil instead of using single turn tapping at one end of the coil. It is much simpler to construct, and the inductance variation will be continuous. It would be better than an ordinary variometer because its time constant will be higher for low values of inductance and the distributed capacity will be lower for high values of the variometer. It is connected in the ordinary variometer circuit. (Continued front preceding page) rent which actuates the phones, as these second variations in the plate circuit are of an audible frequancy and since the by-pass condenser forces them through the phone. The tuning is started by putting the grid negative with potentiometer cutting out resistance in the plate circuit and adjusting other controls until a beat note is heard. This should be made as loud as possible and then oscilla- tions are stopped by using potentiometer and plate resist- ance. A readjustment of the secondary condenser with adjustments of potentiometer will bring in the loudest sig- nals. These rules apply for the tuning of all the reflex sets except those using a tuned impedence coupling be- tween radio frequency amplifying tubes. Circuit No. 2 This hook-up differs only in using a tube as a detector. The plate voltage depending upon whether a hard or soft tube is used, but a soft tube with a vernier rheostat is recommended. The values for the grid leak and the grid condenser are dependent upon the characteristics of the tube used, but values given have been found satisfactory for most of the soft tubes, as specified in drawing. A loop or coil antennae may be used in either hook-up, re- placing coupler by loop of about ten turns on a three foot square using same value of secondary condenser. No panel layouts can be given for the author used phase mounting which is to be recommended for experimenting and the readers are advised to experiment to learn the peculiarities of the reflex circuit before mounting in a cabinet, for it will save trouble. Circuit No. 3 For a set which is very selective and gives very sharp tuning circuit 3 is recommended, for the tuned imped- ence coupling between tube and crystal can be used to separate interfering stations. The tuning is the same as given above except that the additional condenser shunted around honeycomb coil must be adjusted for a maximum signal strength, and as the addition of this variable con- denser complicates the tuning it would be well for the amateur to try out one of the preceding circuits first. By experimenting with different values for the condener and honeycomb coil a smaller value for the condenser and » larger value for the coil may be used, allowing more critical tuning for this unit. Digitized by Google

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RADIO WORLD 7 That Flewelling Super Circuit By Robert L. Dougherty A CIRCUIT that has recently become popular and rightly so, is the now famous Flewelling Circuit. From the amateur's standpoint it is .the most practical circuit of the "super" type that has yet been developed. Because of the fact that it can be used with aerial alone, aerial and ground, or ground alone, one side of a loop, or both sides of the loop, it gives the utmost flexibility. Com- bine these advantages with the fact that it is a most prac- tical and easily-worked circuit (only two controls being necessary), and you have a few of the many reasons for its fast-growing popularity. Because of the fact that large values of inductance are not necessary with this circuit it is probably the easiest and the most stable of all the circuits that use the principle of '•super-regeneration." The tuning is all done by means of If in the construction of this circuit it is desired to use the conventional variocoupler, the rotor should be rewound, to approximately two-thirds the inductance value of the stator, or primary winding. While this is permissible, it is easier to use the well-known duo-lateral or honeycomb coils with the adapter. By doing so, not only is the builder saved the trouble of rewinding the coupler, but as the circuit has been worked out using the values of inductance that are found in the number 50 and 75 coils, there will probably be less chance of trouble originating through this source. By the use of a small loop antenna, in connection with this circuit without any outside amplifiers, extremely loud and clear signals have been received from distances truly remarkable. The audibility of the received signals were equal to those received on a set using 2 steps of radio and 1 *rs DL Diagrammatic illustration of the famous Flewelling Circuit. The moat important part. of this circuit is the condenser bank shown in the diagram; The three condensers should be of the correct capacity, .006, and the leak shunting- them should have a resistance of from % to 3 megohms. This particular leak is not critical in its adjustment, therefore, does mot need chanting. When correct value is found it can be substituted by a fixed leak of like value. The leak in the arid circuit is important, and should be variable. The leads A and B are for antenna and ground or loop. Either antenna alone can be used or ground alone. In either case, when used alone, they should be connected to the post marked K One sidi of a loop can be used with the circuit by fallowing the same procedure. For local work' neither antenna nor loop is necessary. j the plate coil, and the small capacity condenser is shunted across the larger or main inductance. One of the big features of the circuit js that for local broadcast work the set needs neither aerial nor ground, the reception being accomplished on nothing but the set itself. When used with either a loop or outside aerial, marvelous results can be obtained, and on account of the fact that the tuning is not critical, as in the regular "super" circuits, it is easier to control and tune, and there is no C battery necessary, which simplifies it considerably. The tuning of this circuit is simplicity itself, the main adjustments being the coupling of the coils and the setting of the grid condenser values. The coupling relation of the coils is first set at an approximate relation of 50 degrees of each other. Then the grid leak is set until the high fre- quency whistle is either entirely eliminated or is at a mini- mum. When this is done the variable condenser is adjusted to bring in the voice or phone, and the coupling increased or decreased until the signals are loudest 1 step of audio frequency, without the troublesome tube noises so noticeable on a set using audio frequency. When constructing this set, extreme care should be taken in the wiring, keeping all wires that run parallel as far apart as it is possible, and making sure that there is no chance for short circuit. Phones should at least be of 1,000 ohms resistance because of the fact that the inductance in the phone circuit is being Used, and accounts for the absence of the large inductances. The fixed condensers should be purchased, as it is extremely hard to get exactly the right capacity without the use of calibrating apparatus, as even when formulas are correct there is always the chance of the thickness of the dielectric differing a sufficient amount to make it impossible to obtain the correct capacity. As the correct functioning of the circuit depends on the value of capacity in the condenser bank, it will make correct oper- ation much easier and surer. If further amplification of signals is desired, the batteries of the amplifier should be separate from those of the circuit proper. Digitized by Google

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8 RADIO WORLD Mounting Crystal Detectors on a Panel By T. IV. Benson THE simplest and most effective method of mounting a crystal de- tector on a panel is to make use of a double-contact flush bayonet socket as employed on automobiles. The socket is set in a hole drilled in the panel and held in place with the locknut fur- nished with the socket. Detectors for use in this type of socket can be purchased in both the fixed and adjustable types. The con- structor can make his own fixed detec- tors from a' double-contact plug as shown in the illustration. A small piece of the desired crystal is attached to one terminal of the plug - --Pan si riush Socket <D<=V -Lock Hut by twisting wire around it and insert- ing the ends of the wire in the termi- nal. The other terminal is fitted with a short cat whisker made from copper or brass wire. Plug the detector into the socket and adjust the cat whisker - --Cap Crystal- -*<i$S /{--Cat Vhlakei . Double Contact • Plug* Dttalle of fixed Detector* Figure 2. Diagrammatic drawing, awfai intact phut can be easily rands I dustproof, fixed crystal in tlie usual manner until signals are heard the loudest, then carefully place a drop of sealing wax on the cat whisk- er and mineral to lock the adjust- ment. Replace the cap on the plug and fill with sealing wax. A number of these detectors can be made up and no part of a program will be lost on ac- count of the detector going bad. Any other form of detector usually mounted on the table can be fitted with a plug and flexible leads, and plugged into the set when desired. Figure 1, Diagram showing how the headlight socket is mounted on the panel to accommodate a crystal detector. Photograph showing how panel of simple crystal receiver was made. Notice socket in lower right- hand corner, next to Inductanc "Electragists" Is the Name THE annual convention of the Associa- tion of Electrical Contractors and Deal- ers was held recently and it was decided by its members to change the title of the organization, and that it should be known hereafter as "The Electragists." It was stated that this was due to the desire to incorporate in the title the trade-marked word "electragist," by which is meant ,-a member using high standards of practice. r This new title also gives recognition to tht great number of members who are located outside of the United States. This Naval Set is Compact, but Powerful OnJ^KS3RS S (C. Kadel and Herbert) Operator Lester Judd adjusting the quenched spark gap of the new naval V4 kilowatt trans- mitter, such as used on board naval cutters and lightships. Besides being extremely compact, it is one of the most flexible transmitters ever designed, and easily handled, as controls are) ' red to absolute minimum The current for this set is furnished by a separate generator, or the ship's storage battery, which may be used tn case of emergency. com- pactness, and power are concerned may be found on the United States cutters that patrol the coasts and keep masters of ships constantly informed about wrecks, derelicts and storms, etc. It is a 24-kilowat quenched spark type, of the latest design as far as it concerns control and compactness. As can be seen in the cut, there is a visible check on the wave length, which can be read by means of a number dial inside the little white circular hole as shown in the upper left hand corner. The control for the wave length is made by means of the two handles directly next to it. These handles control the coupling and inductance of the trans- mitting tuner, by means of sliding con- tacts, and by varying the angle of coupling. The meter directly next to it is a radiation ammeter, connected in the antenna circuit, by means of which an accurate check on the current being radiated may be kept. Directly below the meter is seen the quenched gap. which is used in place of the usual straight gap or rotary gap. On either side of the gap may be seen the volt- meter and ammeter. Digitized by Google

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RADIO WORLD 9 Building a Power Amplifier at Home By C. White, Consulting Engineer THE use of power amplification is growing very steadily among amateur radio fans. Many no doubt have come to realize the tremendous ad- vantage in audio-frequency amplification on the power tube principle. Unfortunately the cost of these units completely assembled has greatly hindered the average amateur from purchasing one, and, since there is little literature concerning the construction of these units available, there have been a vast flock of fans who have been forced to give the idea up until prices become more favorable. Some fans tried making power amplifiers on the same principle as the ordinary audio-frequency ampli- fiers, using non-power tubes. In general their attempts were far from a satisfactory solution because many factors which would go very little toward aiding or hindering the operation of an ordinary amplifier would either determine the success or ruin of an amplifier on a larger scale. The main reasons for failure have been interaction between the audio-frequency stages clue to the employment of one common A and B batteries; another has been due to the fact that they tailed to use power transformers and the windings of the ordinary non-power transformers have not been designed to stand the relatively large plate current of a power tube; and, third, if any of the previous troubles were avoided, the results were not very en- couraging owing to the large amount of inherent dis- tortion in the output of the amplifier. Home-Made— WeU Made So far those who are still looking for a good system to build a home-made outfit that gives good results, I have designed a little power amplifier that can be built at a rather reasonable price at home. I do not claim that the principle is new, but, it is reliable, since many large firms are making power amplifiers on the same identical principle. Distortion is introduced to a large degree in a power amplifier which is built on the same principle as an ordinary non-power amplifier, that is, using one tube per stage, owing to the fact that the voltage variation on the grid of the tube in the last stage is quite exces- sive and thus introduces serious and sometimes unbear- able distortion, especially on high notes and very loud signals. To overcome this tendency to distortion on the last tube, the voltage variation is divided between the grids of two similar tubes instead of being impressed on the grid of a single tube. This principle is com- monly known amongst radio men as the "push and pull" system of amplification and is employed extensively for amplification of a high degree. Such a double tube arrangement is not necessary on the first stage of the receiver owing to the fact that the voltage impressed on the grid is very weak and unamplified to anv ereat extent. - s It Cuts Down Interaction To cut down interaction between the tubes of the various stages a choking or filtering arrangement is provided. This filtering arrangement consists of a .1 henry choke coil inserted in each lead-in wire and a 1 .0-micro-farad condenser connected between the inner ends of the two choke coils in each lead. In Figure 1 these coils are designated by the letter X. and the condensers by the letter C. Direct current and voltage to light the filaments and supplv potential f..r th» various plate circuits is easily passed through these choke coils, but is practically impossible for any cur- rents of voice or high frequencies to get across from one stage back into another by means of the common A and B batteries. The condenser C offers a path of low impedance for the high frequency voice currents that can pass through the choke coils because of their high impedance to alternating currents. By means of a 250-ohm potentiometer, marked P, the grid of the lirst tube can be adjusted to the correct negative-poten- tial. The two tubes on the last stage are supplied with negative potential for their grids from a common C battery that can be built into the unit and adjusted once for all times. The condenser C-l acts only as a by- pass for radio-frequencies that might be impressed upon the primary of the transformer T-l. The capacity of C-l can be any value between .001 and .002 micro- farads, depending solely upon the type of transformer. Whan and What to Buy Many of my readers are by this time wondering what type of apparatus to get and where to buy it. The condenser C-l is quite easily obtained from any radio supply store, but the condensers C can be purchased from a telephone supply house. Choke coils (X) of .1 henry inductance are also obtainable from a telephone supply depot. The transformer T-l is nothing more than an ordinary audio-frequency amplifying trans- former, but T-2 is a power amplifying transformer with a split secondary. The latter may be had from any manufacturer or dealer in transformers for telephone and radio uses, under the name of amplifying trans- former for "push-pull" type of power amplification. The tubes used for the last, or the "push-pull" stage, must be of the same type, but the tube for the first stage can be of another type, but it is advisable to employ the same type of tubes. In assembling the unit, care should be taken to see that the windings of the transformers have the right ends connected to the grids. If the transformers are not so marked this can be easily ascertained by tryout. This power amplifier can be built up for $40 to $55 com- plete if care is taken to purchase the right apparatus. Such an outfit purchased completely assembled would easily cost $100 to $180. And the only near difficult things connected with the outfit is the purchase of the 1 mfd. condenser and the transformer T-2, which can be done if inquiries are made for the same at a lar£' commc:cial telephone and radio supply dealer or manu- facturer. For those who wish to try out some inter- esting experiments many surprising results can be obtained by the use of non-power tubes in this type of amplifying circuit. Operating Room of WJZ, Newark, N. J. <C. K»drl & Herbert) Tb« tlx tubas tm tb* kft ar» tb* racttfyia* Tb* cabtaMt oa I nW. mm4 MclUalara. bottom tb* Ava tfca rlfbt at tb* tba four Digitized by Google

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming Into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks ~f"T 7 HAT care should be taken of crystals used in i/^f crystal receiving sets? r r Crystals used for the rectification of radio signals should not be handled except with a small pair of tweezers or pincers. The reason for this is that the hand contains a natural oil, which coats the surface of the crystal and renders it less sensitive to the minute currents. The crystals should occasionally be cleaned with a toothbrush dipped in carbon bi-sulphite (commonly called by the trade name Carbona). If the surface of a crystal loses its sensitiveness a new surface can be had by scraping the old surface with a sharp knife. What care should be taken of tubes used as amplifiers or detectors? The filament should not be allowed to burn too high. It is a waste of current, and also materially shortens the life of the tube. The tube should occasionally be removed from its socket, and the base of the lugs rubbed with emery cloth to brighten the contacts. Do the same to the socket. Tubes should be mounted in. the correct position. If a tube is mounted so that its filament is horizontal there is a great chance of its sagging, due to the heat expanding the filament If this occurs and it touches the grid it will short-circuit and burn out. When a soft tube is used as a detector it is common to have them "blue" up. By this is meant a bluish haze forms around the filament and plate. This indicates too much B battery, and the B battery current should immediately be decreased, otherwise the sensitiveness of the tube will be lost Combining Business and Pleasure Votde FRon The- Kif<H£N "Johnny, teT AWAY FROH "ChaT Radio and Takc YOUR BATH!* Are there any decided advantages m having the grid leak variable? As the tubes manufactured today vary slightly as to the degree of exhaustion they are, of course, harder to manipulate should the grid leak, which allows a small amount of the current placed on the condenser to leak across so as not to choke the tube, be variable. This is especially true in the case of the single-circuit, regenerative sets that are so popular at the present time. By varying the value of the grid leak it is possible to make the tube oscillate at lower filament temperature, thus saving the life of the bulb. * * * Is any advantage gained by shunting the phones and B battery with a small capacity condenser? By shunting the B battery and phones with a smaH con- denser you can eliminate to a great extent the troublesome battery noises which are sometimes so prevalent in the present type battery, especially when they are aging. This allows the small, instantaneous current fluctuations, due to internal chemical action of the cells, to partly disappear. * » * Is it possible to operate a twolt tube on dry cells? It is perfectly possible to operate a 6-volt tube on dry cells by hooking up sufficient cells in series to furnish 6 volts. As a dry cell generally furnishes 1.5 volts it would take 4 hooked in series to furnish sufficient current to light the tube. No advantage is gained by using dry-cells, as their life is naturally short, and their constant renewal is eventually more expensive than a storage cell. * ♦ » What is meant by a "negative grid charge"? By a negative grid charge, we mean a negative charge is put on the grid to enable it to hold its negative potential easier. It is generally accomplished by using a small dry cell, such as is used in flashlight cells, connected with the negative lead to the grid. •'» Saturday nifht excursion made pleasant Radio Dictionary Aerial: A system of wires, insulated from the ground and generally suspended at a certain definite height above the ground, connected with suitable apparatus to the earth. Such a system is used to radiate or interrupt oscillations. Aerial Tuning Inductance: A number of turns of wire which can be adjusted to radiate waves longer than the fundamental wave length of the aerial. Amplifier: ' An instrument which modifies the effect of a local source of energy used as a rule to produce a larger indication than could be had from the incoming energy alone. Amplifying Tube: A tube which is exhausted to a higher degree of vacuum than one that is used as a detector. A tube that is not gas filled. B Battery: A high voltage battery, composed of a num- ber of small cells connected in series in order to furnish sufficient voltage to operate a circuit in which a vacuum tube is used. Choke Coils: Coils wound in such a manner that they have great self-induction. Usually a coil of wire wound over an iron core, composed of a soft iron wire, or laminated metal sheets (soft steel or iron) insulated from each other to prevent eddy currents. The function is to check the amount of current flowing in a circuit by means of reaction, due to self-induction. Compass (Radio): A radio device for determining the direction of a radiated signal. Condenser: Two or more conductors separated by an insulator, which is used to store up electricity in the form of electrostatic energy. Digitized by Google

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RADIO WORLD 11 How to Remedy the "Howl" in Your Amplifier By JV. A. Dickson LOOKING for the seat of trouble in an amplifier that has developed a persistent "howl," is like hunting for the proverbial "needle in the hay-stack," and unless the operator is acquainted with the causes and remedies of this objectionable phenomenon it is almost hopeless to try to stop it. "Howling" occurs mostly in cases where the vacuum tubes are transformer-coupled, and can be readily dis- tinguished from other tube noises by its sustained audio frequency note in the telephones, entirely independent of legitimate signals. It is caused by the internal oscilla- tions occurring in the circuits of the various tubes, and- al- though probably more common to audio frequency am- plifiers than radio frequency amplifiers, it happens in both. Studying more closely the cause for these internal oscil- lations, we will take one unit of an amplifier consisting of the secondary of one transformer, the tube itself, and the primary of the other transformer. This circuit is shown clearly in the accompanying diagram. It will be understood that each winding on the transformers con- tains a certain amount of distributed capacity, and this to- gether with the inductance, forms an oscillating circuit — or at least a circuit capable of setting up self-sustained oscillations of a certain natural frequency. If these oscillations are at a frequency which is audible they will be heard in the telephones connected in the plate circuit of the last tube of the amplifier. Even though these oscil- lations are inaudible, as in cases of radio frequency am- plification, the action of the tubes will be seriously im- paired. > Sometimes, however, an audible note is heard in the telephone when the internal oscillations are known to be of a high frequency. This is due to the fact that the grid condenser may become so highly negatively charged that the oscillations are stopped ; but as soon as the electrons which are cbllected on the grid leak off, the oscillations will start again. This intermittent starting and stopping of the oscillations causes pulsations in the plate circuit; and if they are at audio frequency, they will be recorded in the telephones. Considering the amplifier as a whole, it will be seen that if each tube is oscillating, or capable of oscillating, the tubes will all oscillate at practically the same frequency; also that should the oscillations be started in one tube, and are sustained by the other tubes, the entire amplifier will oscillate. Howling is more likely to occur when high ratios of am- plification are employed than when low ratios are used, ana1 so an amplifier that is noiseless is sometimes not so efficient as one which has a slight tendency to howl. The following points regarding amplifiers in general should be observed: Seconlar Y LtH s Primer* Of Trans r**«t*" Details of a transformer coupled amplifier. The circuit completed through the tube la capable of oscillating at a certain fre- quency, because the winding of the trans- formers possesses a distributed capacity. Oscillations would causa tube noises, and would also cause the circuit to howL 1. Using separate filament and plate batteries for each tube does away with a means of coupling between the units and consequently eliminates possibilities of undesired "feed-backs." Of course, this is almost impossible in the case of the ordinary set, but care should be taken that the batteries which are used have a low value of internal re- sistance. 2. Resistance-coupled amplifiers are usually constructed without necessitating the formation of an oscillating cir- cuit. However, an oscillating circuit may be accidentally formed by the arrangement of the wiring. Of course, the frequency at which a circuit of this nature would oscillate would be very high. This might cause a howl audible in the telephone if the grid condenser intermittently starts and stops the oscillations as explained previously. 3. It is always best to keep the plate and grid leak wires as far apart as possible. It is also advisable to plan the wiring so as to be sure that the smallest amount of wire is used in connecting the different components. 4. "Shielding" is a very important matter to be con- sidered, and besides helping to eliminate howling, it does away with the objectionable body capacity effect. Another important feature to be considered in the oper- ation of amplifiers, and also one that is very objectionable, is a foreign noise caused by the tube itself.- These noises are usually in the form of "clicks" or "hissing," and can be caused by unstable mounting of the elements in the tube, ionization of a small quantity of gas in the tube, or an irregular flow of electrons from the filament due to sur- face impurities. When the voltage of the filament battery drops below normal an unnecessary noise is bound to be heard in the telephones. The same applies to the plate batteries which, towards the end of their life, develop a high internal re- sistance. This might happen in any one of the numerous cells composing the battery. When a "hissing" or "fry- ing" noise is heard, it is always advisable to test the plate batteries — not only each battery, but each cell. Wireless from Freighter A REPORT by wireless stated recently that the American freighter "Winnebago" had been disabled by the terrific gales off the coast of Ireland and that she was in need of imme- diate aid. The freighter is owned by the American Transporta- tion Company and has been used in connection with the Amer- ican Relief Administration for carrying food and hospital sup- plies to Russia. This Postal Tells Whole Story Rocky Hill, Conn., February 10, 1923. Gentlemen : I have taken your weekly publication regularly, and have a complete set of Radio Worlds. They are worth their weight in silver to a radio fan. Yours truly, (Signed) C. H. YEAGER. Digitized by Google

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12 RADIO WORLD "How I Constructed and Worked the Set on My Ship" By Captain Leon Mauriet of the S. S. * u Syria BEING on board a low powered steamer, running between Marseilles and New York, I had the idea to try, independently of the ship's wireless, to have a small receiving set in the chart room, and the results obtained were such that I think it may interest other captains or officers. The set can be placed in the chart room or in any other room. Any aeration pipe will do for the en- trance of the aerial. A bolt on a beam will make an excellent ground. The set is not expensive and will give short and long wave length in use on ship or shore stations. During our voyage from Lisbon to New York almost every day we had two or three time signals and errors of our chronometers were daily noted. Longitudes were cal- culated with exactitude. From noon on November 6 to 6 p. m. November 7 we had cloudy weather and fog, with no pos- sibility of obtaining the position by astronomical observations. With this set we heard distinctly the radio fog signals of Fire Island light ship. Pointing the head of the ship in the direction where I thought the signals were the strongest we came exactly on the light ship. The same proceeding enab' d us to go from Fire Island 3 Vcjcuym TkAes Rheostat ' L. S. to Ambrose L. S. and anchor close to the L. S. in a very thick fog. Combining * radio, fog signals, soundings and fog sirens, position was found as accurately as with clear weather. The reading of radio fog signals are easy and in my opinion there is no possibility of error. Putting a long cord to the phone receiver I took it to the navigating bridge, leaving the set in the chart room on the lower bridge. Swinging the ship ten de- grees on each side I knew the exact bearing of the station, and soon after the fog siren gave another certitude. The chart will show where time signals have been heard in day time; during night better results may be obtained. I am explaining the diagrams and lists of things necessary to build the set. With it good results were obtained. A loop, as shown in the cut, will give the bearings without changing the ship's course, but it is not a great loss of time to swing the ship and the antenna does the work of an excellent and big loop. Having a wooden box of hex- agonal form, 18 inches in diameter, 6 inches high in the middle, a separation and an axle one inch thick. Half of the bpx will be divided in Secondary Of Loose Coop/er Top vim of the Mt constructed by Captain Mauriet, Notice the fact that it la la four cabinet*, each abased mo that the let will form a hexagon. Each cabinet is separate, hr 'o by means of 1 Schematic drawing, showing how the est waa mounted to form a small labia. The bat* terles are conveniently located at the base of the table on a space provided for Either a loose honeycomb coOs can i this set, as may be noted. r-r*fl'rr Leon Mauriet and the set ha for his personal use on board the S. S. "Syria." Note the loop antenna that ha usee. The accoav penying text and dtagrama five a fall ileei i hjitin The Captain la an ardent fan and la op-to eati In radio matters. 3 panels of hard rubber or bakelite. The middle one will be fixed with two hinges. On the middle one will be fixed the three sockets for vacuum tubes and one paragon rheostat; wire connections to be fixed underneath the panel and inside the box. One of the side panels will hold a forty-thr*ee plates air variable condenser; the other a 23-plate air variable condenser. Inside of the box, underneath the rheostat, will be screwed a Thor- darson amplifying transformer. In the side panel behind the tubes will be left an open rectang- ular space for a hard rubber panel that will have: Two binding posts for A battery; Two binding posts for B battery. The grid leak and fixed condenser of 0.0001 mf can be fixed thereto. The other half part of the box will receive the loose coupler in the middle, the secondary coming out in the front panel. (Continued on next page) Digitized by Google

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RADIO WORLD Bureau of Standards to Test Seven Standard Waves By Carl H. Butman WASHINGTON, D. C— All radio fan* will be able to test their wave meters on standard wave signals transmitted from the Bureau of Stand- ards, on Tuesday evening, March 6, according to a recent announcement. Commencing at 11 p. m. Standard Eastern Time, the Bureau of Standards at Washington will send the general call "QST de WWV Standard Wave Signals," followed by the signal "WWV" repeated for five minutes on the following waves: 550, 600, 680, 790, 940, 1150 and 1500 meters. In the near future it is hoped more wave lengths will be assigned to broadcasters and it will be advantageous for fans to be able to tune in correctly. If the positions of the variable parts of the receiving sets are charted during the tests, the exact position can be predetermined for any of the standard waves used later on. A Bureau of Standard* Test The tests will virtually furnish a Bureau of Standards test by radio for wave meters. Broadcasting stations should also calibrate their instruments, so as to be able to check their own transmissions when special wave lengths are assigned. Announcements preceding the sending of the standard test signal "WWV" on the seven different waves will be made on that wave and will state the length of the wave in both code and telephone. The standard wave signals, the Bureau explains, may be used by anyone having suitable receiving equipment for calibrating a wavemeter or receiving set. Results from preliminary standard-wave transmission experiments conducted by the Bureau and thirty observers located within 1,000 miles of Washington on January 29 and 30 indicate that such signals are most serviceable after 11 p. m. when broadcasting programs are concluded. The tests also showed that the wave meters of the observers were generally in fair agreement, but some differences were as great as 7 per cent. If the pending radio bill becomes a law, Bureau officials explain it will be necessary for the Secretary of Com- merce to assign carefully selected wave lengths to each radio telephone broadcasting station, as an error as large as 7 per cent, would cause serious interference. In view of this, it is desired that the wavemeters used be in closer accord, and to correct these errors for sending and re- ceiving, standard wave signals will be sent out. Wave Schedule March • The schedule of transmission for March 6 is as follows : Approximate Frequency Wave Eastern Time P. II. 11. -00 to 11:05 p.m 11. -OS to 11:10 11:10 to 11:15 11:20 Kilocycle* Per Second (550) Lcogtli Meters 550 General call Standard wave Announcements General call (500) M0 Standard wave Announcements 11:40 General call (440) 680 Standard wave Announcement! .12 00 General call (380) 790 Standard wave Announcements 12:20 General can (320) 940 Standard wave Announcements 12:40 General call (260) 1150 Standard wave Announcements 1 00 General call (200) 1500 Standard wave Announcements About April 1 standard wave signals will be trans- mitted covering the wave frequency range between 1,000 and 500 kilocycles per second (wave lengths from 300 to 600 meters), and on about May 1 between 2,400 and 1,000 kilocycles per second ( 125 and 300 meters). The last will be of special interest to amateurs. The exact dates and schedules of transmission will be announced later. {Continued from preceding page) Room is left on each side of the loose coupler to place the mounting of 3 inductance honeycomb coils. The antenna used and shown on diagram is a cage of four wires the cross being two feet in diameter, 75 feet in length. The entrance of the aerial is an aeration pipe. An ordinary reflector lighting cable will be insulation enough to bring the aerial to the set. GROUND. A bolt on an iron beam connected with the hull will make an excellent ground. A BATTERY. Storage battery of four to six volts will be easily charged with direct current from the ship's dynamo. B BATTERY. A dry battery of .30 to 80 volts will stand working for several months. 1 Aerial 7Sfeet 15 PWes .OOOS % Sec. Diaffraai of Digitized by Google

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14 RADIO WORLD Radiograms The Latest Important Radio News Briefly Told for the Growing Army of Radio Fans SINCE they have begun to broadcast in Mexico, President Obregon has become an ardent radio enthusiast. He has had an up-to-date set installed in his home, Chapultepec Castle, to keep him amused in his idle moments. After the manner of most fans he went from idle curiosity to highest ardor. * * * GREAT BRITAIN wakes up to the fact that radio broad- casting is a public need, and has opened four stations. Each one operates on a wave length sufficiently different not to cause any interference with -any other. That's the stuff, but watch your step when you start to license them by the dozen, or you'll run out of numbers for the wave lengths. The sta- tions licensed and their calls and wave lengths are : 2LO London, 369 meters ^2ZY Manchester, 385 meters; SNO Newcastle, 400 meters; 5IT Birmingham, 420 meters. * * * DUTCH EAST INDIES will not bo left behind as far as reception of long distance is concerned. The man- ager of the radio station at Bandoeng, Java, Dutch East Indies, recently filed a report that he has successfully copied the trans- mitted signals from the station at Ongar, England, whose call is GLO. This is a distance of 7,500 miles, and the reception was done on an antenna 45 feet long, the receiving set using two vacuum tubes. The work was done on a 4,350-meter wave- length, and is an indication that even in Java, "you can't keep a good man down" when it come to DX work. » * * THE purchase of Station WDAP which has been operated by the Drake Hotel, Chicago, was recently made by the Chicago Board of Trade, for the purpose of broadcasting farm service and quotations of interest to farmers. * * * THE latest fashions in the way of aerials is gold plating. Be- cause of the fact that there is a great deal of efficiency lost, because of skin resistance when copper wire corrodes due to the action of the air on the copper, a Chicago amateur, R. H. G. Mathews, central division manager of the ARRL, one of the best known amateurs in the country, is using gold-plated wire for his antenna system. That's O. K. but don't advertise the fact, or some dark evening you'll be missing some perfectly good antenna wire. * * * WHAT is now considered one of the finest stations' in the world is WBZ, the Westinghouse radio station at Springfield, Mass. This station was recently rebuilt, and as a result it gives results considerably louder and clearer, and has also increased its range. This station was first opened in the fall of 1921, as a pioneer station in the broadcasting field. At first it was designed to serve only New England and there- fore its power was limited. But when broadcasting became popular, the need of a more powerful station was felt, so the old station was dismantled and the new and more powerful one erected. * * ♦ IT is now possible for the students of Columbia to include radio in their course of study. The course requires two ses- sions and is intended for those who are not familiar with the theory and practice of radio. * * * DR. LEE DE FOREST, a graduate of the Sheffield Scientific School of Yale University, class of 1906, recently gave a sum of money to be used by the University for the purpose of establishing an up-to-date radio laboratory and library. An annual course of lectures will be provided for students taking the course, and the lecturers will include some of the foremost radio and electrical experts in the country. Beginning with this month, a series of lectures will be given by the following: G. A Campbell, American Tel. and Tel. Co. ; Lloyd Espenscheid, American Tel. and Tel. Co.; S. C. Hooper, United States Navy, Dr. Albert W. Hull, Yale '05, General Electric Co.; John More- croft, Professor of Electricity, Columbia University, and L. E. Whittemore, Bureau of Standards. Senator Kellogg Hopes for Action on Radio Bill By Washington R. Service WASHINGTON, D. C— The radio bill, which was referred to the Senate Interstate Commerce Commission recently, may be passed this ses- sion of Congress, Senator Frank B. Kellogg of Minne- sota believes. An effort to hold a meeting of the Senate Sub-Com- mittee on Radio a few days ago failed because of lack of a quorum, but the White Bill, which has already passed the House, will, it is said at this writing, be taken up by that commitee soon. Senator Kellogg, who has been interested in radio legislation for over a year, is making every effort to secure passage of this much-needed legislation. He is being aided by Congressman White of Maine, who will meet with the Senate Committee to give the mem- bers the benefit of his extensive knowledge gained through the recent important public hearings in the House- Senator A. B. Cummins, chairman of the Senate Committee, who has been ill for some time, is expected back in the Senate, and it is believed by the supporters of the White Bill that his presence will aid materially in securing the attention of the Senate. Considerable difficulty in getting the bill before the Senate, even after it is reported out by the committee, is anticipated in view of the other pending legislation, including the Ship Subsidy, British Debt Settlement and other bills urged for immediate consideration. Sup- porters believe, however, that within a few days the Senate will have arrived at a position where the legis- lation for consideration this session will be definitely decided upon, and they believe the radio bill will receive consideration before adjournment on March 4. NEXT WEEK! CRYSTAL DETECTOR'S DEPARTMENT WILL BE CONTINUED NEXT WEEK! Digitized by Google

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RADIO WORLD 15 The Milwaukee Amateurs' Radio Club Vl>tft *5 I !i 5.- « «^ Ottlcers and directors ol the Milwaukee Amateurs' Radio Club, seated in Ibe Hunt row (ielt to rixbt): Messrs. L. a. band, C. N. Crapo. E. W. • Ruppenthal, H. F. Warein*, H. C Fawcett, E. T. Howell, I. H. Straw man, and A. J. Simandl. MILWAUKEE, Wise— The Milwaukee Amateurs' Radio Club was founded in January, 1917, by L. S. Baird, A. I. R. E., and associates, and became affiliated with the American Radio Relay League, Inc., in 1919. The society is enjoying an active and suc- cessful season and meets weekly at 7:45 P. M., oh. Thursdays, in the Trustees' Room of the Milwaukee Public Museum. Meet- ings have been well attended, and the mem- bership is increasing. Meetings are devoted to talks by members and reports from committees. The techni- cal committee, headed by E. T. Howell, Sc. M., and R. E. Lathrop, 9ATX, has sub- mitted several reports on topics of timely in- terest. The "S" tube has been discussed; super-regeneration explained; an analogy given for oscillating vacuum tubes ; and the Hartley and reverse feed-back C. W. cir- cuits contrasted. A spirited spark-C. W. debate was put over recently with great success. The ar- gument waxed hot, and the sound of the gavel was frequent. A contest in defining technical radio terms caused many lines to be spelled down, but resulted in adding a large store of words to the members' vocab- ularies. Several meetings have been devoted in part to the discussion of the proper de- sign and construction of aerials. 'Marian Szukalski, Jr., 9AAP, owner of the only Milwaukee amateur station to span the ocean in the recent transatlantic tests of the A. R. R. L., presented a paper on the construction of his transmitter. Officers of the society this year are: H. F. Wareing, president; H. G. Fawcett, secre- tary; and L. S. Baird, business manager. All general communications should be ad- dressed to the club's executive office, 691 Enterprise Bldg., Milwaukee, Wis. My Airplane Antenna The following letter has been received by one of Radio World's contributors: January 17th, 1923. Mr. Ortherus Gordon, 87 Smith St, Fall River, Mass. Dear Sir: I have read your article in the January 13th issue of the Radio World. The state- ments that you made were of consider- able interest as the writer is working along the same lines that you are, and the results that I am getting are mighty in- teresting. You mention that you can tune out Round Hill station but 20 miles distant. I have only an Aeriola Sr. set — no am- plification whatever — using a W. D.-ll tube, lit with a No. 6 Columbia Dry cell— 22^4 volt Ever-ready No. 766- B battery, and my various aerials. I am located in the Kentucky Hills about 9 miles due south from WHAS, Louisville, Ky. ; and when they are com- ing in, it nearly knocks one's head off. I have several aerials as follows: (a) — 150 ft. outside running due north and south some 30 ft. from the ground. (b) — 150 ft. aerial installed on the roof of an enclosed porch about 11 ft. from the ground. The wire lies in what might be called a rectilinear spiral, following the sides of the porch and the several revolutions are about 18" apart. (c) — What I call my aeroplane aerial (from the similarity in appearance) made like sketch No. 1 of tin and tuned by the variometer and condensor as shown in sketch. I use the several aerials from time to Getting/ i fro n t?oa The "air-plane antenna" as constructed by Lock* Etheridge, of Louisville, Ky. The results ob- tained on this antenna ere fuBjr described In hie interesting' letter to Mr. Cordon, The construc- tion of the antenna is shown in full detail. time, comparing the same station at the same time, one aerial with the other, and in this way get some idea of their com- parative value. Trying to be honest with myself in the observations I really cannot decide that any one is better than the other. They are all excellent. I get New York City, Newark, N. J., Atlanta, Ga., Fort Worth, Texas, Schenectady, N. Y., College Park, Ga., WMAN, Round Hill, S. Darthmouth, Mass., Cleveland, O., Detroit, Mich., Davenport, la., Kansas City, Mo., Denver, Col., Dallas, Tex., Havana, Cuba, Minne- apolis, Minn., Toronto, Can., East Pitts- burgh, Pa., Chicago, 111. Aerial C consists or four planes of tin, each 14"x20", the edges of which are cut in sharp teeth with the teeth running all around the edges and looks like a rec- tilinear buzz saw. These four planes are mounted one above the other, forming a 4-plane aeroplane without any tailpiece. They are held about 2J4" apart with supports of tin at the four corners and the structure soldered together. The whole combination is supported with an iron rod placed vertically down through the center of the four planes. The upper end of the rod is bent into a hook and insulator so I can hang it on the ceiling of the room over my head. A wire is fastened from the bottom plane for a lead-in wire — and the variometer and condenser are cut in series into this wire. This train of apparatus comprises the aerial C which is connected to the set in the usual way. Try this out and you will be surprised at what you will get from stations 1,000 miles distant. Yours very truly, LOCKE ETHERIDGE. R. R. 2. Kenwood Hill, Louisville, Ky. i Digitized by Google

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16 RADIO WORLD Radio News Photos Fn Over the World Captions by Edward Lynn (c; lis at J (C. Kadel and Herbert) The antenna system of the Radio Corporatlon-Westinghousa Sutton. WJZ. located at Newark. N. J. The six-wire ported between two 12*- foot steel masts. It la 1M met loo* feet above the street level. <C. Kadel and Herbert) A novel way of advertising, which keeps the avri is (C Keystone Views) Master John Marvin Ferree, of St. Paul, Mine, krak fame at an early age and acta a quotaboa oa tat ■ (C. Photos by Boice Studios) The operating room and studio of one of the Largest college broadcasting stations, WHAZ, Rensselaer Polytechnic Institute, Troy, N. Y. This station has just established what is said to be a world record for radio telephony, having successfully maintained two-way phone communication ov - ''tance of two thousand miles between the stations at Troy, N. Y., and Calgary, Can v' ' was successful In transmitting a complete concert to the Hawaiian nds, a distance of over 5,5*1 miles. Digitized by

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RADIO WORLD a All ind Herbert) r Mayor of Rio i Brazil, and hi* •ymg the Ike station > da Janeiro, the (C. Underwood and Underwood) Radio has been called open to assist the police la the location of stolen automobile*. The photograph snows Sergt. CUvereua, of the Waehingtan police force, broadcasting the daily automobile theft reports, with such data as make of car, number and other identification marks. A decided decrease In the number of stolen automobiles has been noticed since this new method went into use. (C. Underwood and Underwood) Mr. Tracy T, Hicks, of Kansas City, Mo., and his new pocket wireless receiver, which is unique m that it is self-adjusting and no tuning or bat- teries are necessary. It Is practically complete in Itself. All that is necessary Is to attach the clips to a suitable ground and aerial. (C. Kadel and Herbert) Miss Henrietta Seek, the "Voice of th * and one of the announcers, both well to listeners of WDAL, the radio broad- casting station at Jacksonville, Fla. This Is the only station between Atlanta and Miami, and has been heard distances of over 3, MS miles. (C. Gilliams Photos) The Piedmont High School at Oakland, Cel., has inaugurated a unique Innovation in install- ing a device called the tele meg- aphone, by means of which the principal is enabled to get in instant touch with all the class rooms. He la also enabled by this device to control the re- ceiving of the local stations that broadcast educational data and lectures. The loud apeakei Is seen on the upper left-hand of the accompanying photograph directly over the blackboard. (C. P. and A. Photo) Miss Florence McDonald, sister of the president of Chicago Radio Laboratories, will keep in touch with Chicago while enroute to Europe, on board the S. S. Berengaria, through the aid of radio. (C. Underwood and Underwood) Admiral Sir Edmund Robert Fremantle, England's oldest naval officer, Rear-Admiral of tile United Kingdom since Ufl, listening in to the phone concert being broadcast from the Eiffel Tower, Paris, in the cabin of H. M. S. Impregnable, hie old flagship. The set being used is one of the English type, utilizing ing both radio frequency and audio frequency =========

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18 RADIO WORLD A Radio Golf Card That Will Interest Two Kinds of Fans no * x Who 80 R Period at Data Januarv 24.1923 Player E. Share* Boeivina Station is Looated at HlllDrook.K.Y. of Play. I Boors 45 Klnntes.Frosj 7:45 to 9:30 rxHJs STATION LOCATION of STATIOM MILEAGE 7 - AR war Soheneotadv,H.Y. 80 .1 ■Pv - w e a r K.T.City 90 1 ■ Sfl W G T Medford H1H-««,U..«. W J z HamriulUL ■ 89 — ; W I P . Philadelphia^ Pa. JSC 8:10 ILI Cincinnati .OWj, , 625 •JTjg ■ ujir Po»keep«ie.N.Y. 15 8:20 1 ff ff A E Pittsburgh, Fa. 350 S P ft A Pittslrarcrh.Pa. 350 8 -.88 W N A C Boston. Haes. 150 8:30 1,8*5 Louisville rKv- 700 £^35. ISB Atl*ntarGa. 840 ■SrW ,., W D A P ghloayor111- 740 . 3 142 WEAK Providenoe.R.I.* 125 8:49 840 SiSS W P 0 M—PhlB.T^p.* 1000 tlOO K Y W Chicago -111. 740 9:04 IF1I Twpuhit Kmi— -> 1200 9;I<7 SI B X CharlotterN.C.a 675 9:13 (3D St.Loul»:Jla*_ 950 ?;I5 Kit Arlington. Va. 290 9:18 V W J Detrolt.Mieh. 500 9:20 CarroHton.MO, 1075 9:23 Davenport , Iowa. 900 £4 TOTAL I26I0 Miles AVERAGTS2S.4 Miles Total Humber of "Holes" Made_ Average Length of Drive 525 Miles Gain Over Previous Play 8600 Miles Remarks:— Hade about 7205 Miles per Hour on This Wight. (Signed) • Stations heard for first time on this nlghtr. * Editor, Radio World. Sir:— Please find enclosed a copy of my blah icon Golf Card aa secured on my 2-tube regenera- tive set. This U my highest record so far and I average about S.tM miles or more every night. I think this score beats the one published in your issue of February 3, US. Yours truly, (Signed) E. SHEROW. Meanest Thief Steals Radio Receiver From Disabled Soldiers in Hospital THERE might be honor among certain thieves, but there certainly is none among those who stole a radio receiving outfit from the disabled soldiers who are being treated at the General Hospital in Cincinnati. This radio receiver was providing a tre- mendous amount of amusement for those boys who came back from France physical wrecks, was ' aiding them in keeping their minds off their suffering and was assisting them in passing the long afternoons and evenings in the hospital. For months it had been in use, and the best care had been taken of the instrument and all accessories. Then came a thief in the night. Wires were cut. The receiving set, batteries, tubes, loud speaker and every- thing were carried away. When the soldiers entered their recreation room the next morning their receiving station was gone. Police were notified and the Cin- cinnati newspapers carried accounts of the theft, but a search of several days has failed to reveal any indication as to who took from these wounded heroes their sole source of amusement. Now this radio receiving set was donated to the soldiers by the Crosley Manufactur- ing Company. This company gladly will give another instrument to the boys in the hospital. But we believe there are many readers who would like to contribute a small amount toward buying another set. Let's all get together and make these lonesome and suffering boys happy. Don't be ashamed to send in a small amount The Crosley Radio Weekly starts the ball rolling with a contribution of $5.00. Who is next? Advances Its Own Employees IT was announced recently by C D. Knight that no position of any great responsibility will be filled from the outside at the Bloomfield plant of the General Elec- tric Co., that is, not until after a thorough investigation has been made to ascertain if an employee of the plant can be fittingly advanced. It seems it will be necessary for employees to register with the examining board of the company in order to qualify for the positions desired or vacant This board was organized a year or two ago. Its object is to assist present employees to ad- vance in the organization. New Use for the Pallophotophone IF you have tuned in to 370 meters re- cently and have picked up WGY you have probably been surprised at the purer and truer tone quality of music and speech from the General Electric Company broad- casting station. The answer is the Pallophotophone. A new use has been found for the re- markable device which photographs sound on motion picture film and then reproduces the sound from the film. C. A. Hoxie, the inventor, has now devised a pick-up, or microphone, using the principle of the Pallophotophone reproducer. The microphone is the link between the artist or instrument in the studio and the electrical circuit; it converts or transforms the variations of tone into corresponding variations of current. Microphones now in general use are constructed on the prin- ciple of the telephone transmitter, in which the compression or expansion of granular carbon affects the electric current. In the Pallophotophone pick-up a very sensitive diaphragm is set vibrating by sound. The movement of the diaphragm is communicated to a mirror three sixty- fourths of an inch square. A strong light strikes the dancing mirror, which reflects the light beam at a sensitive light cell The variation in the beam of light, caused by the vibration of the mirror, varies the effect on the light cell, and thus produces a corre- sponding variation in the electric circuit Amplification is then obtained in the ordi- nary way by means of pliotrons. The new pick-up eliminates the hiss which accompanies the use of the ordinary micro- phone; it is more sensitive and responds more readily and accurately to sound waves, capturing harmonies which would ordinarily be lost. A feature of the new pick-up is the weight of the moving or vibrating part. The diaphragm and mirror combined weigh one-tenth of a grain, or half as much as the head of a common pin. • The Pallophotophone pick-up is now a permanent part of the studio equipment of WGY. Many letters complimenting WGY on the improvement of its tone quality were received after the program of Jan- uary 30, when the play "Bought and Paid For" was put out through the new pick-up. Radio Locates Missing Man *"pHE value of radio in locating missing persons has been demonstrated again by WGY. The studio director was recently requested to ask for the whereabouts of Louis Gordon, formerly a sergeant with Company B, 301st Military Police Corps. Gordon was wanted to substantiate the claim of an ex-service man who was dying in a Buffalo hospital, and letters to his last known address had been returned. The request was made by H. M. Laughlin, county claim agent of the Chautauqua County Committee, American Legion. Within twelve hours after the broadcast request for Gordon he, the missing man, saw a lawyer, drew up the necessary papers and mailed them to the claim agent. Later other Gordons throughout the country wrote in, giving their full names, addresses and the outfits with which they had been during the war. All offered to give any assistance they could. Head- quarters of the State Police, Harrisburg, Pa., sent in full records, descriptions, etc, of two Louis Gordons serving in the troops in that state. Digitized by Google

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RADIO WORLD Answers to Readers AINDLY give me a hookup embodying one step of radio frequency m the regu- lation two variometer regenerative set, with one step of audio frequency, as published in Radio World dated February 3. — Bert Beckhous, 2901 Wasp Road, Fairview, N. J. Hookup you request is published herewith. Kindly publish a hookup for the follow- ing apparatus: Variocoupfer, 2 variome- ters, 1 step of radio frequency detector and one step of audio. I am using two steps of audio at present, but believe that one is sufficient. Is it advisable to use radio fre- quency in a set of this typet — R. W. Noble, Hookup published in answer to inquiry of Bert Beckhousa, The hookup is a regenerative set. with on* step of radio and one step of audio- frequency. Kindly advise trie where I can get the wiring diagram of the type of set described by Cranby Meyers in his article "How I Planned My Regenerative Receiver." The article I refer to was a panel layout of a set with detector and two steps of audio frequency. — M. A. Murray, 300 Sturgis St., St. Paul, Minn. If you will refer to Radio World dated February 3 you will find a suitable dia- gram on page 19, in answer to an inquiry by Mr. Anorthy. You will notice that the last tube of this set has no rheostat, the current being controlled from the rheostat of the second tube. * * * Kindly publish a hookup using detector and one stage of audio frequency in con- nection with the article by Ortherus Gor- don, in Radio World dated January 20. — George C. Bowen, Box 154, Fond du Lac, Wis. Hookup you request is herewith published. 24 Summit Ave., Wollaston, Mass. Refer to the diagram published on this page in answer to the inquiry of B. Beck- hous. Radio frequency is perfectly advisa- ble in a set of this type. * * * 1. What kind of a tube should be used in the reflex circuit as published in Radio World dated January 20, page 11/ 2. Will a loose coupler built according to the Bureau of Standards, circular 121, work with this circuit? I am using formica in- stead of cardboard. Is this advisable t — B. B. Graeff, 4308 Woodlawn Ave., Los Angeles, CaU 1. A hard tube of the U. V. 201 variety is the best for use in this circuit, as it has to perform the work of an amplifier. 2. Your loose coupler will be perfectly correct, if care is taken in the construction of it. It can be used in this circuit (.Continued on page 27) requested by George C. Bowen. The amplifier uses a separata A battery to light the filament. MAGNAVOX is "news" THE constant allusions to Magnavox Radio equip- ment in the public press, and ■ the numerous illustrations of Magnavox Reproducer in oper- ation, show how profoundly the radio world has been influ- enced by the Magnavox elec- tro-dynamic principle of sound amplification. R-2 Magnavox Radio with 18-inch horn THIS instru- ment is in- tended for those who wish the ut- most in ampli- fying power: for large audi- ences, dance halls, etc., but requires only ,6 of an am- pere for the field. R-3 Magnavox Radio with 14-inch horn SAME in principle and construc- tion" throughout as Type R-2. Is ideal for use in homes, offices, amateur stations, etc. Requires one ampere field cur- rent from your filament battery. Magnavox Power Amplifier — Model C CAN be used with any "B" Bat- tery voltage which the power tube may require for best ampli- fication. AC-2-C, 2- Stage and AC-3-C, 3-Stage The facilities and experience back of each piece of equipment bearing the Magnavox trade mark are unrivalled anywhere in the world. Magnavox products may be had of good dealers everywhere. Write to us for illustrated booklet The Magnavox Company Oakland, California 'New York Office : 370 Seventh Ave. Digitized by Google

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20 RADIO WORLD The DX Nite Owls Break Records Peanut Tubes and a Home- Made Set From C. A. Perkins, 341 North Washington, SINCE several fellows have taken a "crack" at Kenneth Smith at Birming- ham, Alabama, I guess I will take one, too, and incidentally step on the toes of M. P. Bailey of this city. I am using a Reinartz Tuner and one step >f amplification. In all I have heard seventy- five different stations. I have heard as high as nineteen different stations during one evening. The following are a few of them: KH J, Los Angeles; CJCA, Edmondton, Al- berta; C J G, Winnipeg; WMAG, Liberal, Kansas; WKY, Oklahoma City; WRAP, Ft Worth; WFAA, Dallas; WOAF, Kansas City Star; WHB, Sweeney Automobile School, Kansas City; WGF, Des Moines; WLAG, Minneapolis; WOC Davenport; KSD, St Louis; KYW, Chicago; WCX, Detroit; WSB, Atlanta; CFCA, Toronto; WGY, Schenectady. Who can beat this with peanut tubes and a home-made set? I have a one-wire aerial sixty feet high and eighty feet long; inverted L. 26 Stations on List From N orris Johnson, Jr., SS Pr.ithor Avsnus, Jamestown. New York AS a new reader of your publication I wish to state my interest in the depart- ment "With the DX Nite Owls." My own records are none too impressive, but they might be of interest to your readers. My station consists of a vario-coupler. variable condenser of .0005 capacity, V. T. detector and single-stage amplifier. I in- tend to make a three-circuit regenerative in the near future. The following stations I have heard within the last two months: New York-Buffalo, WGR; Schenectady, 2X1, WGY; Troy, WHAZ; New York City, WEAF; New Jersey-Newark, WJZ, WOR; Springfield, Mass., WBZ; Pitts- burgh, KDKA; Philadelphia, WIP; Morganstown, W. Va., WHD; Atlanta, Ga., WSB, WGM; Detroit, Mich, WWJ; Indianapolis, Ind., WOH; Chicago, KYW, WAAF, WDAP; Davenport, la., WOC; Minneapolis, Minn., WLD, WJAP; St Louis, Mo., WSD; Kansas City, WHB; D. C. NOF. In all I have heard 26 stations in 13 states, and the District of Columbia. On a One-Tube Set From Jos. Honnors, 134 Wheeler Strest, GloucssUr, Massachusetts 1AM sending my receiving record for a one-tube set, using a 23-plate variable condenser and a vano-coupler with two switches. The stations I heard are : WNAC, Boston; WGI, Medford; WBZ, Springfield; WGY, Schenectady; WEAF, New York; WHAZ, Troy, N. Y.; WJZ and WOR, Newark, N. J.; WOO, KDKA, Philadel- phia; WWJ, WWI, Michigan; WJAX, Cleveland; WOC, Davenport, la.; Mon- treal, Canada, and many other smaller stations in the East. We Don't Think So, Either From Kenyon Daley, IMS Third Avenue, South Minneapolis, Minnesota AM a steady reader of the Radio World and have just been reading the DX records of many fans using one tube, so I will send you mine. WMAC, Cazenova. N. Y.; WDAL, Jackonville, Fla.; W hnectady, N. Y.; WGL, Philadclr' Vlanta, Ga.; HE Editor of RADIO WORLD wU ebao of hoek-t : Jnk or I OwV who T tftMMMif to receive sketches of the -DX Nits hi records with a view to •f they of the rut— RADIO WORLD. WGAM, Orangeburg, S. C; WFAA, Dallas, Tex.; WKAF, Wichita Falls, Tex.; WRAP, Forth Worth, Tex.; WPA, Forth Worth, Tex. ; CKCD, Vancouver, Can. I alto have 16 more under 800 miles. I am using a stand- ard short wave regenerative set consisting of grid and plate variometers, variocoupler and a 43 plate variable condenser. My aerial is a two-wire, inverted T type, twenty-five feet above a three story apartment house. I don't think my record is bad for a home- made set. Here's What He's Donel From Frank P. MoCaDm, Of West tth Street. TnotBBa N*tw Jarwy NOT being a DX Nite Owl, as you call them but a fan who has spent con- siderable time monkeying with radio since it began, and also a regular reader of Radio World, I am wondering if you would care to see my set, one of three that I use. This particular set has been giving very wonderful results and considering its sim- pleness and low cast of construction, there are few who cannot afford to have radio in their home. One night from 7:15 P. M. until 12:30 A. M., not long ago on the accompanying hook up came KDKA, WJZ, KHJ, WEAF, WIP,- WFAA, KSD, WOR, WCX, WDKF, besides two Trenton local sta- tions. Not only once but numerous times, especially on clear, cool evenings, have 1 done this. This set consists of 23-plate variable con- denser, Freshman grid leak and condenser combined. Bradley stat (none better on the market and I have tried them all), Essex Bank wound variocoupler, 180*, Atwater Kent socket. WD-11 tube, Red Seal dry battery for tie "A," and for the "B" I use a toy transformer I used formerly to run an electric train, and from the house current AC 110 volts, cut down to 22J4 volts, with 3-25 watt lamp in series with the socket and the transformer. You'd be surprised 1 I would be pleased to give any one any information on this who cares to write to me, for "B" batteries cost money and AC current you use for light anyhow in your room. So it is small expense considering the current used. Made It Himself From Wm. H. Jonas, IS Donvor Av tady, New York HAVE been a Radio World for about 6 months now. Three weeks back I make a tube set myself. De- tector and one stage amplification. Have re- ceived stations at New York and Pennsyl- vania. The best distance I have made so tar is WOS, Jefferson City, Inco., and WOC Davenport, Iowa. Another Good Crystal Record From J. R, Yonne, MS Padfie Hfekway, 1DONT think many can beat my record. I hear KGW in Portland nearly every night they broadcast and KFAC in Eugene loud. On Monday, Jan. 15, I tuned in KFCB in San Francisco, about 500 miles distant The concert came in fine for about half an hour. My set consists of a vario coupler I made myself and an aeroplane crystal detector, a Murdock condenser and a pair of 3,000 ohm Murdock phones. One-Tube Circuit of F. P. McCulHn 25,420 Miles in a Night From J, E. Bradley, Austin, Texas LAST night I started working at 5:45 p. m., and was on the air until 3:1S a. m.— 9 hours and 33 minutes. I received call letters and names of towns of 41 stations. Had a home assembled set— 1 detector and 1 stage A. F. A., using W-D 11 tubes; 16 volts on plate of D tube and 455. onplate of A tube. My farthest point was KPO, San Francisco— an orchestra mat was much plainer than several nearer stations. Some of the stations I would get just as they were signing off, and I could work several in short time. I stayed on KSD about 25 minutes. They had the Bell Telephone Orchestra on, and the music was fine. Below is a list of the stations as they were caught WAAD, 5:45 p. m, Cincinnati, O., (test). 840 ; WOC, 5:55 p. m., Davenport, la, 700; WSB, 6:45, p. m., Atlanta, Ga., 750; WOAL 6:50 p. m., San Antonio, Texas, 300; WDAF, 7:00 p. m., Kansas City, Mo., 460; WGM, 7:05 p. m., Atlanta, Ga., 750; WOQ, 7 :10 p. m., Kansas City, Mo, 460; WPAC 7:20 p. m, Okmulgee, Okla, 175; WCAE, 7:30 p. m, Pittsburgh, Pa., 1,100; WCM, 7:32 p. m, Austin, Texas, 175; WAAR 8:00 p. m, Huntington, W. Va. , 940 WEAH, 8:45 p. m., Wichita, Kan, 350 WHAS, 9:00 p. m., Louisville, Ky, 760 KLZ, 9:10 p. m, Denver, Colo, 625 WD AH, 9:15 p. m., El Paso, Texas, 550 WGV, 9:40 p. m., New Orleans, La, 450 KSD, 9:50 p. m, St Louis, Mo, 575; KFI. 10:20 p. m, Los Angeles, Cal, 1,175; KPO, 10:22 p. m, San Francisco, Cal, 1,425 WLAG, 10:25 p. m, Minneapolis, Mum, 875; WDAP, 10:30 p. m, Chicago, 10, 825; KDZQ, 11:00 p. m., Denver, Colo, 625; KHJ, 11:20 p. m, Los Angeles, CaL 1,175; WJAP, 11:40 p. m, Duluth, Minn, 1,025; WJAX, 12:20 a. m, Cleveland, 0, 1,000, WJD, 12:45 a. m, Granville, 0. (test), 925; WCAL, 1:00 a. m, Northfield, Minn, (test), 850; WDAL. 1:42 a. m, Jacksonville, Fla., 925; WHA, 2:27 a. m, Madison, Wis. (test), 840 ; 9ZQ, 2:30 a. m, Lincoln, Neb. (test), 550 ; 8X1, 2:53 a. m, Columbus, O. (test), 940; CFCA, 3:11 a. m, Toronto, Canada, (test), 1,225; WDAJ, 10:47 p. m.. College Park, Ga., 750 ; 2 Waco, 3 Dallas and 2 Ft Worth stations, which I call local stations. They figure 330 miles. Total, 25.090. Grand total, 25,420. Digitized by Google

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RADIO WORLD 21 The Limitless Possibilities of Radio for the American Farmer By Major-General James G. Harbord President of the Radio Corporation of America RADIO and its achievements by General James G. Harbord, President of the Radio Corporation of America, was pre- sented to the Hsteners-in of the Westing- house Radio Station KDKA recently. Gen- eral Harbord's talk in part ran as follows: "Within the past year and a half a new phase of radio has fascinated the whole civ- ilized world. Radio telephonic broadcasting first successfully initiated on a public serv- ice basis by the Westinghouse Electric k Manufacturing Company, though still in its infancy, is already practical. It promises social, political, economic, educational and religious possibilities second only to the art of printing. "The relations of broadcasting to the farmer group themselves naturally under two heads: * "(1) Utility. "(2) Entertainment "A very casual consideration reveals a much varied application of radio broadcast- ing to the interests of the farmer. Un- questionably radio emerges from such a sur- vey as a part of the necessary business equipment of the efficiently operated farm. The radio receiving set will be to the farmer what the ticker is to the speculator in farm products. It will be the equipment which will place you on even terms with the man- ipulator of your markets. The dissemina- tion of market news, weather and market reports stands out obviously as a primary function of broadcasting. It is absurd to argue with an intelligent farmer on the benefit of advance knowledge of weather and markets. "Radio may perhaps lead to a solution of many of your labor problems. During har- vest or other rush seasons when labor sup- Sly is of manifest importance to the fanner, roadcasting might well call attention to available labor supply. Acting with your existing facilities for securing labor, broad- casting will enormously expand their scope. It will contribute to the fluidity of the sup- ply, enabling farmers in need in one region to draw on the labor surplus of another. "Already through the jmblic health serv- ice medical advice is afforded by radio to ships at sea without medical attendance for their passengers and crews, and lives have been saved through such wireless treatment There is no dearth of information as to proper procedure in case of animal epi- demics. The problem is to make such in- formation instantly available. The farmer who in such time of emergency must act promptly either lacks the time or the in- clination to consult a distant authority, nor can he safely keep a herd of such steers or cows waiting while he wades through the mass of pamphlets in the hope of finding the particular treatment he wishes. The limiting factor in such cases is accessibility. The same is true of regions where insect pests are devastating crops. By giving the farmer just what he wants when he wants it, broad- casting will widely extend the emergency services of the various agencies which the Government has created to help him. "Nothing in the farm field is more im- pressive to an outsider than the extension of co-operative action in recent years. 'Just as common interest is a powerful motive in co- operation, so the dissemination of common intelligence and the maintenance of contact are conditions which make the promotion of common interest possible. _ Some of our states have farm bureaus in every county. Information sent out under their auspices would further the purpose of such bureaus, and get their information and their policies to the individual members with the speed of light. One state, for example, has over two hundred grange halls. The state master is investigating radio apparatus with the idea of placing receiving sets in every such halL The possibilities of radio broadcasting in facilitating the purposes of farmers' organ- izations are practically limitless. "The head of a co-operative group of farm papers has figured that the territory served by his publication includes over five thou- sand grain elevators, and about the same number of livestock shipping associations. It at once occurs to him that every grain elevator in the region ought to maintain a receiving set in its office tor business rea- sons. It is no less true of the livestock shippers' associations. It is equally true of the intelligent individuals who constitute the membership of such organizations. "The foregoing are specific applications of broadcasting, meeting specific needs. Per- haps the greatest general utility of radio to the farmer is in tying in with the ex- tension work of the agricultural colleges and schools and the various state organizations devoted to improvement of farm methods. Today a relatively small number of farmers, workers or owners, benefit from such in- struction. The exigencies of farm work do not often permit enrollment for full terms. Radio would open the door of the agricul- tural school to tens of thousands who would otherwise never receive such institutional in- struction, and it would enable the student who has been obliged to terminate a short course to continue his studies in many cases under the same faculty. With practical men in charge of such instruction the possibili- ties of radio in this direction are limitless." Radio Address by Legion Official " THE United States Veterans of the World War were addressed last week by Lemuel Bolles, National Adjutant of the American Legion, by radio from broadcast- ing station PWX. There was a special program of both Cuban and American music, mostly of a military strain, and some of it was reminiscent of war-time days. The program commenced at 9 o'clock, Eastern Standard Time, and the speech by Mr. Bolles was made about an hour later. Station PWX has been heard in many parts of the United States and Canada, and as far north as Alaska, with an effective radius of 3,000 to 4,000 miles. Los Angeles Station Heard in France and China (G Kadel and Herbert) T. E_ NUdrk, owner el Station MCA, located in Loo Angeles, and bio one tube set. Mr, NUdrk ie an otoVthner In the fame. Hie pro-war was 3VU, and his "fief ie wall known to a groat many amateur*. This station has boon hoard by ships In the harbor of Yokohama, as as by stations in France, the calls having been verifiod by cable and letter. The eet shown In the photo is capable of radiating IS Digitized by Google

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22 RADIO WORLD Adrertismg Rates, Display, %SS30 per inch, $15000 per page Radio Merchandising Classified Quick-Action Advertising, 5 cents per word Telephone Bryant 4796 American Radio Exports Growing By W ashington R. Service THE exports of wireless and telegraph apparatus from the United States during 1922 showed a very large increase as against the figures for 1921. In 1922 the value was $3,214,098, compared with $1,010,- 891 for 1921. Radio apparatus exported in 1922 totaled $2,897,799, and in the month of December, $163,236 worth of equip- ment was shipped abroad. The increase of radio and telegraph apparatus in 1922 was due to the tremendous interest shown in radio throughout the world, appearing even in the most un- likely places. The fascination and appeal of radio ap- pears to be universal, and its development would go forward still more rapidly were better broadcasting facilities provided, the Department of Commerce has announced. Radio Corp. Granted Tempo- rary Injunctions Against Three Firms New Radio Firms JUDGE AUGUSTUS N. HAND, in the United States District Court for the Southern District of New York, recently handed down decisions in three patent suits brought by the Radio Corporation for infringement of the DeForest audion patents by the manufacture and sale of vacuum tubes for radio purposes. In all three cases Judge Hand granted prelim- inary injunctions asked for. The first of these suits was that of the Radio Corporation of America against La France Import & Sales Company, Inc., and others, who are manufacturing and selling a vacuum tube known as the "La France" detector and amplifier. The second suit was against Harry Ro- senthal and others who are manufactur- ing- and selling a vacuum tube detector and amplifier known as the "Perfection" tube. The third suit was against the Radio Guild, Inc., a dealer in the "Perfection" tubes. One of the principal defenses urged upon the Court for a denial of the pre- liminary injunction motions was that Radio Corporation of America had no rights to maintain the suit because the DeForest Radio Telephone & Telegraph Co. was the owner of the DeForest audion patents. This defense, as well as other defenses, were overruled by Judg Hand in granting th preliminary injunctions. (The new firms and corporations men- tioned in these columns can be reached directly or by communicating with the attorneys, whose addresses are given when ever possible.) . Apex Electrical Supply Co., Manhattan. $20,000: C. M. Lcfkowitz. R. Z. Weigbaum, H. Storv. (Attorney. B. R. Leinhardt. 44 Court St., Brook- lyn.) Stuyvesant Radio Corp., Manhattan, make electric and wireless specialties, $10,000; A. Klein, C. W. Hanes, G. M Jost. (Attorney, L Conn, 1540 Broadway.) j H. P. Ha user. Manhattan, make electric sup- plies, $10,000: H P. Hau.er. C. J. Schroff. (At- torney, F. W. M. Schroff, 580 Teasdale Place.) Kaskade Radio Corp., $250,000; Theodore L. Ernst, S. E. Freeland, Samuel Baras, New York. (American Guaranty St Trust Co.) Rose 4 Tom son, Manhattan, electrical contract- ing, $10000; T. Tomson, A. T. Rose. (Attorney, J. P. Bromell, 17 East fed St.) Radio Stocks (Quotations as of February 14, 1923, fur- nished by Frank T. Stanton &■ Company, 35 Broad Street, New York City, Specialists in Wireless Securities.) Stock Bid Asked American Marconi Stamped 5c 15c American Marconi Unstamped $5 $7 American Tel. & Tel , 12254 122H Canadian Marconi 2\b W De Forest Radio 7 12 Dubelier Condenser 6 6H English Marconi com 12 15 English Marconi pfd 12)4 15% General Electric 188*4 1» Hennessy Publications 9 U Mackay Company com 110 115 Manhattan Elec. Supply S3 55 Marconi Int. Marine 8 10 Radio Corporation com 3)4 Hi Radio Corporation pfd })i Spanish Marconi ft Western Union US 115% Westinghouse E & M 62 H S3 Coming Events PERMANENT RADIO FAIR FOR BUYERS. Hotel Imperial, New York City. Open from September, 1922, to May. 1923. SECOND DISTRICT RADIO CONVENTION, Hotel Pennsylvania, New York City, March 1, 2, and 3, 1923. FIRST UNIVERSAL EXPOSITION OF IN- VENTIONS AND PATENTS, Grand Central Pal- ace, New York City, February 17 to 23. inclusive, FIRST INTERNATIONAL EXPOSITION OF INVENTION'S AND INVESTMENTS. Grand Central I' * %v York City, February 16 to 23, i i 1 • GOOD -WILL By DR. FRANK CRANE Many people regard the "good-will" of a concern as more or less an airy nothing. They are inclined to smile at it. Looked at one way, it seems quite tenuous. Over a century ago Lord Eldon defined good- will as the "probability that the old customers would resort to the old place." In the practical business world, however, this mere tendency of mind is of immense and solid value. Millions of money have been spent for Sheffield cutlery, for Delft pottery, for Venice glass, for Paris fashions, for Gobelin tapestry and for Cremona violins, money which wai drawn to these goods simply because of Rood-will. Good-will may be intangible and invisible, but so is electricity. And electricity is very powerful. What is known as "watered stock" has in many instances been nothing but good-wilL And this was so powerful that the profits accumulated squeezed out the water, and the public has eventually bought the stocks at a price many times the value of that originally represented by the visible assets. All business is built on service, and (rood-will representing public opinion of that service comes near to being the foundation of business. Great fortunes are built up on good-will which is fed by proper advertising. In times past monopoly was supposed to be the basis of great merchandising success. In the modern world, however, monopoly is becoming more and more difficult, if it is not becoming impossible. In other words, pood-will is eating up monopoly. Good-will recognizes the public as the final arbiter. It makes a man's success rest not upon a patent right or a government privilege, but upon the favor of the people. Instead of this foundation being a shifting or an uncertain one, its solidity will be made plain to you if you will step into the next shop and inquire what goods have the greatest sale. You will find that it is those goods which rest upon a strong and vigorous good-will which has been built up by persistent and judicious advertising. For instead of being a by-product of modern business, advertising is its very basis. (Copyright, 1923. by Frank Crane in New York Globe.) Digitized by Google

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RADIO WORLD 23 Broadcasting Programs of Unusual Attractiveness from Feb. 25 to March 3 WGY General Electric Co.. 8chenectady. N. T., Week of Feb. 26, 11*23. Eastern Standard Time Radio Broadcasting Program of WOY for Sunday, Feb. 28, 1923. 10 :M a. m. — Morning service of Albany 8treet MetbodUt Church, Rev. A. D. AngelL 4:30 p. m. — Vesper service, with sermon by Rev. A. F. Marcley, pastor of Llsha's Kill Reformed Church. 7 £0 p. m. — Evening service of Albany Street MethodUt Church, Rev. A. D. Angell. MONDAY, FEB. 26 12:08 at. — U. 8. Naval Observatory time signals 12:30 p. m. — Noon stock market quotations. 12:40 p. m. — Weather report on 485 meters., 2 :00 p. m. — Music and Household talk. The Decorative Rlckrack Braids. (Courtesy of "Modern Prlscilla" Msgaslne.) 0:UO p. m. — Produce market and stock market report and quotations; news bulletin*. 7:40 p. m.— Musical program, tarnished through the courtesy of Consolidated Car- Heating Co., Albany. N. Y. 1. Orchestra selection— "Who Cares" Bornsteln Consolidated Orchestra Weldon J. Vatl. piano; L. Bomback, violin - a B. Hevers, violin; O. Welngarten, cornet: R. Stewart, cornet; B. Whitby, French horn; H. Alexander, saxophone; Ouy Orlffln, banjo: J. F. QUI, banjo: Earl Burns, drums and xylophone; J. M. Colton, clarinet— leader. 2. Selection— "Kentucky Babe" Oelbel Consolidated Olee Club Eugene Hart, 1st tenor; O. Pickett, 1st tenor; Clement Sertl, 2nd tenor; C H. Van Leu van, 2nd tenor; H. J. Male, 2nd tenor, director; Ouy Orlffln, 1st bass; H. Alexander, 1st bass; Geo. Trueedale, 1st bass; J. F. Hill. 2nd bass; W. Frederick, 2nd baas; Elmer Ludlum, 2nd bass. 3. Piano solo— "Military Polonaise" Chopin Catherine Anderson 4. Tenor solo — "Thora" Adams Hugh J. Male 5. Walts— "Moon River" David Consolidated Orchestra 6. Mixed Quartet— "Smile Through Your Tears" Hamblen Jessica M. B. Male, soprano; Catherine Anderson, alto; H. J. Male, tenor; W. Fred- erick, baas. 7. Address— "The Kenetron Rectifier" B. R. Cummlngs, Radio Engineer, General Electric Company 8. Selection— "Smllln' Through* Peon Consolidated Olee Club 9. Piano duet— "Third Erolca Symphony'* Beethoven "Allegro Con Brio" Catherine Anderson snd Weldon J. Vail 10. Tenor solo— "If I Were a Rose" Hesselberg Hugh J. Male 11. Instrumental selection— "The World Is Waiting for the Sunrise" Belts Consolidated Orchestra 12. Selection — "I Shall Meet You". -Sanderson Mixed Quartet 13. Bass solo— "Out on the Deep" Lohr W. Frederick 14. Selection— "Can't Yo' Heah Me CaJlIn'. Caroline?" Roma Consolidated Olee Club 18. Fox Trot — "Just One More Dance".... Curtlss Consolidated Orchestra TUESDAY, FEB. 27 12.-00 m. — D. 8. Naval Observatory time signals. 12:80 p. m. — Noon stock market quotation*. 12:48 p. m. — Weather report on 488 meters. 2 AO p. m. — Music and Household talk. 6:00 p. m. — Produce and stock market quotations; news bulletins. , 7:40 p. m.— Fish Raising and Planting. How the 8upply Is Kept up for New York State Fishermen. Sumner N. Cowden, field superintendent. State Conservation Commis- sion. 7:48 p. m. — Radio Drama, "Why Smith Left Home.'' 1. Instrumental selection — "Greenwich Vil- lage Follies" Victoria WOY Orchestra 2. Farce— "Why Smith Left Home" George Broadhurst THE CAST John Smith, who loves his wife and Uvea In New York— Edward H. 8mlth General Vllletboux (his wife's second husband) Frank Oliver Count Von Guggenheim (who made them twisted) Frank Flnrh Major Dnncombe (with memories of last night) James R B. Mollarkey Bob Walton (Mrs. Smith's brother) .. Edward B. St. Louis Mrs. John Smith (who loves her hus- band no matter where be lives)... . Viola Ksrwowaka Miss Smith (a lady in waiting) 7. Ida My rick Julia Mildred Le Tarts Act I. — In the Smith's Apartment. Morning. 3. Instrumental selection — "Valse Divine". . Reynard WOY Orchestra 4. Farce— "Why 8mltb Left Home" Act IL — Same ss Act I. — Afternoon. 8. Instrumental selection — "Medley Over- ture" Staaay WGY Orchestra 6. Farce— "Why Smith Left Home" Act III. — Same as Act L — Evening 7. Instrumental selection — "Blue Jackets March" Emerson WOY Orchestra WEDNE8DAY. FEB 28 12:00 m.— Time signals. 12:30 p. m. — Stock market quotations 12:45 p. m. — Weather report on 485 meters. 0:00 p. m. — Produce and stock market quotation*; new* bulletins THURSDAY, MARCH 1 12:00 m.— U. 8. Naval Observatory time signals 12 :30 p. m. — Noon stock market quotations 12:45 p. m. — Weather forecast on 483 meters 2:00 p. m. — Music and address 6:00 p. m. — Produce and stock market quotations; news bulletins 7:43 p. m. — Concert program. L. instrumental selection — "York Pageant Music" (Request) Noble WOY Orchestra 2. Contralto solo— "Still Wle die Nseht".. Boom Emilte Hennlng 3. Instrumental selection — "A La Bicn Almee" Schutt American Trio 4. Piano aolo— "Japanese Study" Poldlnl Elmer Tldmarah 5. Cello solo — "Sarabande" Correlli Ernest Burleigh 6. Contralto Aria— "Ombre Mai Fu," from the opera "Serae" Handel Km tilt Hennlng 7. Instrumental selection — "Reve Angel- lque" (Request ) Rubinstein American Trio 8. Address — "Dust Explosions" (Courtesy of D. a Dept. of Agriculture.) 9. Instrumental selection — "Serenade, Op. 20" Chamtnade American Trio 10. Piano solo— "Juba Dance" Dett Elmer Tldmarah 11. Contralto aolos— (a) "The Birth of Morn" Leonl (b) "The Kerry Dance" . . .Molloy Emilie Hennlng 12. Violin solo— "Sonata" Solomonson "Second Movement" Edward A. Rice 13. Instrumental selection — "Prelude" Jsmefelt WGY Orchestra FRIDAY. MARCH 2 12:00 m.— U. S. Naval Observatory time signals. 12:30 p. m.— Noon stock market quotations 12:45 p. m.— Weather forecast on 480 meters 2:00 p. m.— Music and Household talk "Finance In the Home," Mrs Edward P. Pressey. 6 :00 p. m. — Produce and stock market quotations: news bulletins 0:30 p. m — Resiling from "Grimms' Fairy Talcs." by Kolin Ha iter. 7:40 p. m.— Health talk. 7:45 p. m. — Concert program. L March— "Leyton" Atmay Salvation Army Band, Samuel Sister, Director 2. Tenor aolo— "My Dreams" Teatl Ernest A. Morris 3. Cornet solo — "Tramp, Tramp". . Goldman Arthur Stone, with band accompaniment 4. Selection— "The Unseen Line" Hawkes Salvation Army Band 8. Reading— "The Inventor's Wife" Anon Maude Lenox 6. Euphonium solo — "Old Folks at Home" Foster Albert Tompkins 7. Tenor solo— "Life" Speaks Ernest A Morris 8. March— "Fielding" Scotney Sa! ration Armv Rand 9. Brass Quartet— "Franc'onla" Goldamltb Charles Fahye. cornet ; John Galloway. euphonium: Fred Fahye. cornet; Allien Tompkins, euphonium. 10. Reading— "l>airot>ert. The Jester". .Nesbit Maude I,enox 11. Selection— "Eventide" (by request) ■•• Rtmracr Salvation Army Rsnd 12. T.-nor sol. — "When You're Near".. Brown Ernest A. Morris 13 March— "Peniance" Langworthy Salvation Army Band D-X- (DUTANCaV) The Thrill of Your Life Whan rou Bns hnx a roles frost s ship at as*.— pall la a saw thfin UMt D-X-rUcUo la isUls InMnisMnu danud tor D-X i DIS- TANCE i Wort To rorolvo <naunt autlsas ps* ■as "m um proper oquipauBt. Oer taasnusaati sra bollt tar Dliuac*. SPECIAL GENUINE FISCHER IM* VARIOCOUPLER regular run SPECIAL PRICE. swailt with all (Mora, Cbaeks *r sumps ** sow**! Mmcaunfij* aMppad psat paid *M of aUattaalcoL Fr*« Catalog** on Raqoast D-X-Radio Co. IS* Liberty ■least Kew York (My 15 March— "Stand to Arms" Marshall Salvation Army Band FRIDAY. MARCH 2 (Late Program) 10:30 p. m.— Mualcal program. TUB RAGGETY-TAGGETY MINSTREL SHOW Part I. Orand Opening Number — Medley of South- land Melodies Clarkson WGY Orchestra "Radlomlnstrelsy " RaggetyTaggety Minstrels Male Quartet Selection— "My Old Kentucky Home'' Foster Radio Four Some "Black Traab" Raggety-Taggety Minstrels Tenor Solo — "Faded Love Letters'' Moore- Dulmadge Raatus Johnson Orchestral Selection and Finale to Part L Medley of Recent Poular Southern Songs Including "Lovln' Mam,'' "Carolina Rolling stone." "Swanee Cradle," "Away Down South." WGY Orchestra Radio Four Olio. .Novelty Xylophone and Banjo Selections THE RAGGETY-TAGGETY astNBTRRL SHOW Part IL Orchestral Selection "School Days" WOY Orchestra The Dark Town Village School ••• aUggety-Taggety Minstrels Male Quartet Selections: (a) "Kentucky Babe" Oelbel (b) "Hanrln' out de Closer. .Hall Radio Four Driving Away the Blues •••:• • Baggety-Taggety Mlnstrela End Man Song— "When My Shoes Wear Out from Walk In'. I'll Be on My Feet Again" ScEroeder Lew Waakmgteai Humorous Dialog** rl„, Lew Washington sad Osuisaj tireiiestrsl Selection— Medley — ' K. hoe* from Imie" Bocbford W<;Y Orrheatra Male Quartet Select Ion— "Carry Me Bsek to Old Virglnny" Foster Radio Pour "Jokef.it" Raggety-Taggety Minstrels Hans Solo — "Asleep In the Deep" Petri' Ntchodcmua Ssinaon Grand Finale Minstrels and Orche-' Digitized by LjOO^ IC

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24 RADIO WORLD RADIO PANELS Oat axaeUr te au» aad akfcwad wlthta II lies HOT wm lash. •/II ud takes a ale* Balsa. BpatUl agar. uT!Z. IUH. tl.M. Poatac* paid. WILEY PANEL CO. till a*. Oaatral Park Am. Ohlsa**, lit tan* shirt manataatarar waata aetata to Mil complete Una of ahlrta, pajamas. Land nightshirt* direct to waarar. Ad \ vertlaed brand-exclusive patterns-easy /to MIL. No eipeiienca or capital re- quired. Entirely n*w proposition. Writ* far Am xnwatojL fleee Skirl O*. »0h *»..«■«,. ELKAY RADIO PHONE From Factory to Yoa 3800 ok ma adjustable head- band, S loot cord, aval a ah ona guaranteed at give entire aatiif action, ar ton ay refunded. Equal to any about am tba market. Sliiinili, C O. D. ar Mknay Order. The ELhy C»,i2f7 Market St., Newark, N. J. ! NOVO\ UB" BATTERIES NOTE THE INSULATE!) BINDING POSTS AND Tin. WI RE CONNFCTOR OVO MF'G CO. SURPRISED? ■ WE REPAIR ■ ■ VACUUM TUBES Detectors ^mplifjers, WW aad Guaraataa Tkaaat W.D.-ll not accepted for repair Ukkaaii HARVARD RADIO ■ LABORATORIES ■ Boston I. Mae*. TabM rstanwd Paiaal P»at 0.0.0. ■ Radio Beacons Guide in New York Harbor THE three radio beacons used to guide ships into New York Harbor and to keep coastwise steamers in their course are on Fire Island Lightship, Ambrose Lightship and Sea Girt Light station, says the New York "Times." The radio apparatus of each bea- con sends out a definite signal at regular intervals, enabling the radio compass oper- ator on board a vessel to take a bearing or determine the position of the ship. To elim- inate interference time schedules have been arranged for each beacon. The Sea Girt beacon sends a group of three dashes for sixty seconds, with a short interval between each group, and then is silent for six minutes. Fire Island sends a series of two dashes for twenty-five seconds and is silent twenty- five seconds. Ambrose beacon broadcasts a series of one dash for twenty seconds and remains silent for twenty seconds before, sending the next series of dashes. The sig- nals are repeated rapidly, so a vessel can quickly find its hearing. Sea Girt, for ex- ample, transmits about forty groups of dashes a minute. The beacons operate on schedule continuously during foggy or hazy weather on a wave length of 1,000 meters. The power of a beacon is approximately one kilowatt. An automatic motor-driven tim- ing switch is provided to produce the de- sired signal at regular intervals. Spring Radio Survey in Alaska THIS spring when a field party from the Coast and Geodetic Survey journeys to Alaska to make a longitudinal survey, radio will play an important role. Previously the line telegraph has been used to secure stand- ard time signals for surveys of this sort, but in remote places beyond the ordinary confines of habitation, telegraph lines do not always extend. In order to receive at any desired point, the party will be equipped with a special portable radio receiving set built at the Bureau of Standards, which with the aid of relays will record saw-tooth lines on a re- volving drum, indicating the pulsations of the standard time clocks at Annapolis and San Diego, three and two thousand miles distant. At eight temporary stations on the shores of Alaska from Dixon Entrance to Skagway, the portable station will be erect- ed and the time signals received by wireless for comparison with local astronomical time in checking the exact longitude. Previous experiments in the southwest in radio recep- tion showed that it was possible to record time signals with an error of less than 100th of a second. The Navy will send out spe- cial signals at a time convenient for their reception by the scientists. To many anxious inquirers: RADIO WORLD has no free |Ut. One copy ia aent aa a voucher to each advertiser or advertising agent represented in current iasuea. All other copiea are paid for or subscription or through the newa trad* FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City Please send me RADIO WORLD for months, for which please And enclosed $ subscription rates: SiagW Cory » Tare* Months LSO Six Heaths J.00 -Oae Year ' " -on) *.» Add f Foreira Po. aa Poet- ■ar- PATENTS im—iiHi maiausd. Trad* Marks n O. a. aid abroad. Can ar write. Fill ADVICE. Pheaa, ViodarhUt rill. 800K^S2Q FIFTH «VE NEW TCP* WE ARB MANUFACTURE** OP PINE RADIO FVRNrTURE— CABINI AND ROLL TOP DESKS. II I1METS. TABLES CS. Hy da*!*, and Keataa oak by a*. THE SOUTHERN TOY COMPANY r. R. C VARIOMETERS With IV4" Dla ROTO ■•— Hah. Staters, Seeaaal • r» •rat* Oaatatt Baahlet*, SSI t* 100 Mater*. "» Prompt Attention to Mail Order* B. E. JARVTS, Inc. Ill-Ill Mask**!* etrast mat M. I. L|\ D SUPER- • Vm IV. CRYSTAL -The Vacua** TuWa Only RtvaT Wlll Mak* Year Crystal hat ha* LM* Baass'i BMtmV— —50* EMmU R*S*> aad R. F. Crystals— II.N, JAYNXON LABORATORY 17 DCY STREET. MEW YORK CITY CRYSTAL FANS Are you satisfied with your crystal, or do you want better result*? MOLYBDIC GALENA A new detector just discovered is sensitive even when ground to dust Send 50c for one of these wonder crystals. We will refund your money if you are not entirely sat- isfied. Phoenix Radio Laboratory Box 168, Phoenix, Arizona PATE To the Man with an Idea I offer a a enced, efficient legal protection, hi* ths Send sketch or model aad descrip- tion, for advice aa to coat, Kerch through prior United States patents, etc. Preliminary advice gladly furni*hed without My experience ud familiarity with variou* art* frequently enable ma to accurately advice client* a* to probable patentability before they go to any expense. RICHARD B.OWEN.Patsat 31 Ows* Ballala*. WashladM. 0. C. M7S.e WMhnrlh Bid*.. New V*rt cttj Digitized by

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RADIO WORLD 25 w\ WHMnVJ DMaJan sf TH» UtfHO OOSPOKATION W jYkOOUCA aeaent »M« lM» " anpUsanta in tlMlr atrrleaa as wtwlii Opacasan u out QnduaU*. InwUnu til In* althar Mr H0»O • in tUdla DKMCB iwrnwi of Formerly Marconi Inttituto Vow T«t OUr WATCH THIS LITTLE AD OP BIG SPECIALS *7.»» MirM. JHt Ota Pfeaeae 1 2. St isaslse KIM AjmIIsmm Heraa All Wm Ceeelsra. !•• ta SMS waters. . . IM Off— Cauflara, allk enseal Omtim: 14 tasa, aietaH aaaaaatlaaa. I5T^Des PtaHja. ».»•.• DaeaSe M Mats 'diiiiiiiii' i'i.'mTo' Metal WMefa II.SS 4.M 4.M I.7S Ml I.M .is Cos* voiln Order — 4 Uoto Pottage WHITE RADIO COMPANY IB E, Brd St. New York City i k * — It:, Air-Muse RtcanW. $£.oo Rang* 5t to 5M MUm " The famous AIR MUSE receiver eooMM of Oak cabinet, bakelite panel, eelectiye and primary toning. So simple a child can install and operate it Broadcasting- sta- tiooa programs heard perfectly. This re* ceirer ia absolutely guaranteed or money refunded. Sent poet paid anywhere in the U. & A. on receipt of Eapreee or Poet Office Honey order. WD Ohm doable headset *U* Set complete aa uiustrated UJS AH other radio accessories at manufac- turers' prices, Detroit Radio Company ONE WEST Mth STREET NEW YORK DefA W El- canT Q .w¥aes •"mm, LOUD SPEAKER V It hum the natural functions at the human throat. The receiver is the vocal cord (A); the long tapering inner bora U the throat (B); and the sounding-board^ at the top la the roof of the mouth (Q. A guarantee of superb tone. Is adjusted for regenerative two stages of amplification, also fire tube radio and audio frequency. Special phone, cord and plug, price $30.00 PTO. B. New York. If dealer can't supply, we can. Full line of radio parts. Dnkn nrltt far aur snSMltlaa Bel-Canto Corporation 417 East 34th Street, Now York City RADIO WORLD TECHNICAL EDITOR ■■San I* Peaaaattj Nat 1% 1* i St. list. IMFORTANT NOTICE we Is sakaa at taat and Microphone Connection in the Waldorf-Astoria Hotel THE radio broadcasting apparatus of sta- tion WJZ, Newark, is now connected to a microphone in the turret on the north- east corner of the Waldorf-Astoria Hotel. And, as explained by the New York "Times," inconvenience and loss of time re- sulting from a trip to Newark prevented many entertainers from going there. The wires connecting the microphone run under ground to Sixth Avenue, where they emerge and join with WJZ'S extension to St. Thomas' Church, and then run to Walker Street, where they pass through a switch- board used exclusively for WJZ'S exten- sions. Three copper wire cables lead from the switchboard through the tunnel to New Jersey, where they mount the Western Union poles and continue to the Westing- house radio station at Newark to be broad- cast to the many thousands of listeners. Direct Communication Between Honduras and New Orleans Vacuum tube transmitters with a power of 20 kilowatts and a normal operatine range of 1.500 miles are u«ed to provide direct communication between Tesriictealpa. Hon- duras. an ti •ajy.aw^^jttl'ifijt I.SI4 1.7(7 •riff ••• W. AOAMS STIICtT GALENA CRYSTAL ■noun taxi is specially Jte. Uncounted 25c All taMcL MauiufactUTwrs, Dealan mmi Jobbara write for quantity price**. We also manufacture Radio Parts to order Precision Tool & Mfg. Co. ltt Lewis Stxett, Now York GOODMAN 1 Ike _.. Only UM « PT «a 1 ah. L. W. GOODMAN DREXEL HILL, PA. DHVta aanna aa aajaj aaak eia aw*. GITHKN8 TSDTONB RADIO BORN — LOUD 8PRARRR Oittrthtatara eetd Daelara. araie / AUTO PARTS MFG. CO. ISIS TrimStr Ave.

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26 RADIO WORLD "The One Outstanding Problem Is That of Broadcasting" So Says Hon. Ralph C. Watrous, Former Lieut. Governor of Rhode Island, in an Analysis of a Questionnaire Conducted by the National Radio Chamber of Commerce ACCORDING to the results of a na- tionwide inquiry, conducted by the National Radio Chamber of Commerce, for the purpose of establishing a standard on SEND MB TOUR PHONES for repairs. All make imiutHt. Reasonable Mmr. in Wert 1M at. Mew York Radiate Your Home U«t Our Price 18.00 Frt.nl Phones 15.93 1.50 Kloin.r Vernier Rheostats .19 1.75 Brliht Bur "II" Bat- terlee. 22'-. rolt 1.10 T 70 43 Plate Vernier Con- dMM «.TS «.«0 IS RMS Vernier Con- deruer 4.15 5.00 WD-11 Trtn«(ormer 3.76 1 00 WD-ll Socket 41 22.50 Bnaul Lnuil rtpeakcr 10.50 4.75 Variable Condenser 43 Plate 2.00 Write /rw free catalogue. Perfection Para Parcel Poet Perfection Radio Corp. of America I Hi VafcBT tSKO 8TKEET, NEW YORK Jut Off Press I WEBSTER'S New Moo.ni ENGLISH DICTIONARY MS COPYRIGHT ILLUSTRATED SELF-PRONOUNCING RADIO AND WIRELESS This Is the Only Dictionary Published DevotJnx • Special Section to Radio and Wireless. There are Listed and Defined about IN* Words, Terms and Phrases most Commonly Used in three Popular flrlennos A Superior Abridgment. Hla-hest Rankhuj Authorities Give Stan dln( Above All Others. She i'WV.xt Beund I* Sell Gralaed Fabrlkeld MF Biek Paeer Revised and Brought Right Up-to-Date— Contalninc Many Special Features Not Found in Any Other Dictionary. All NEW and LATE WORDS Special Prominence is Given a Dictionary of all the New and Late Words, Including those especially re latin* to the World War and other words In the Arts and Sciences that have lately come into our language. General Vocabulary 020 Patee. Adequate far Evary Ordinary Dictionary Need. The 300 Pan R erf ere nee Library Intludea Eapaelally Ueetul StiSHTl ' VrlcaV^ffaliTlrad" TF 'A PRINT 14*3 New York City which radio broadcasting can hereafter be based, certain outstanding facts were brought forward. Foremost among them is that fewer and better stations should be established. An important drawback to present-day broadcasting is the number of stations that are working on a narrow ,band of wave lengths and consequently interfering with one another to an extent that it is a nuisance. The Chamber of Commerce sent a ques- tionnaire to persons representing various phases of the broadcasting art, from manu- facturer to listener. The replies were an- alyzed in a statement made public by for- mer Lieut.-Governor of Rhode Island, Ralph C. Watrous, who is now a member of the Special Committee of the Chamber of Com- merce, appointed to make a study of the situation, and to make recommendations that would benefit the greatest number of people. The Chamber warns that a serious eco- nomic question exists and asserts its pur- pose "to keep broadcasting within the hands of the public, to whom this means of new communication belongs." Passage of the White Bill giving greater power to the De- partment of Commerce is urged. Response to the Questionnaire "The one outstanding problem is that of broadcasting,'' says the statement. "The re- sponse to the questionnaire was very grati- fying and pointed the way in several direc- tions very clearly. Most prominent of all was the idea of 'fewer broadcasting sta- tions with better programs.' No exact num- ber of stations was generally recommended; and this could not well be as the range of stations is so rapidly changing, both as to their efficiency and also as to the steadily increasing receiving range of more efficient receiving sets. Btit that progress would be more rapid when we realized the necessity for fewer stations seems a perfectly safe deduction from the answers to the question- naire. "The matter of 'better programs' seems to be very naturally related in the minds of those answering to the expense of furnish- ing really good programs, but it does not seem to matter who pays for it or how. The more people who can be served by a single station the less, of course, the ex- pense per listener! This economic question is a very serious one and in the interests of the general radio public must be dealt with very carefully. However, of course, the people as a whole interested in radio must finally in some way pay the bill. "Another matter clearly brought out by the questionnaire was that proper legisla- tion should be enacted in Congress that would not only safeguard our Federal de- partments but give to Secretary Hoover's department the power to so regulate radio, and broadcasting in particular, that the greatest service shall be realized by the greatest number. "It would seem that the questionnaire also clearly indicates a line separation between public broadcasting stations from the sta- tions operated largely in experimental work by our amateurs who served such a useful purpose during the war and who hare done much constructive work. They must hare a place, but their power and range must not be allowed to interfere with the public's use of this new means of communication to aa unreasonable extent "The question of wave length* was dealt with in the questionnaire but this is a mat- ter that will have to have much thorough study and any solution of this problem can only be covered temporarily as changing conditions will make necessary frequent changes in any provision inserted in the new law. "The White Bill now pending in Con- gress provides for a Radio Council and the selection of this Council made in a way to really represent the whole radio public is about as important a matter as confronts us. We frequently hear the idea expressed that the more broadcasting stations the bet- ter, for a great number will sooner awaken the public to the impossibility of satisfac- tory service under a system of numerous stations. "This is absolutely wrong and the Na- tional Radio Chamber of Commerce be- lieves that all that is needed is to call at- tention to the necessity of reduction and the American public will respond and make its wants known in no uncertain way. Not Favoring Any Croup "It was made clear in the questionnaire that answers were not desired if they were to be given with the spirit and intent of favoring any group, class or corporation; but rather that the matter shall be so con- sidered and the answers so given that it would be apparent the interests of the gov- ernment and the entire radio public were paramount" The number of radiophone sets licensed by the Department of Commerce for trans- mitting purposes in the United States totals approximately 570, it was said. Data cov- ering 340 of the broadcasting stations has been gathered by the Chamber in a study of transmitting range. It was found that forty stations have a range of fifty miles, sixty-nine stations a range of 100 miles, seventy-three of 200 miles, forty-three of 300 miles, eight of 400 miles, sixty-one of 500 miles, eight of 700 miles, seventeen of 1000 miles, nineteen of 1500 miles, and two of 2000 miles. The weighted mean transmitting range of all broadcasting stations in the United States was given as 368 miles. R*vdk> World, S2 i SiiIjsi filx direct or taaTovsjtt Bows dealer. $6.00 • year. $3.00 months, $130 thro* months. World. 1493 Broadway, N. Y. C SEND TJS THE NAME OF YOUR RADIO CLUB Also the names of your president and other officers. We want to add these to a Uat of radio clubs and officers we are preparing for publication In an early Issue. RADIO WORLD. 1401 Broadway. New Torn. Digitized by Google

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RADIO WORLD 2 MURDOCK 3000 Ohm Phones No. 57 3.75 (While thrj Uet) ECLIPSE RADIO COMPANY 414 West 4*od Htree. Hew Yarn City CABINETS Hinsed Top. Beautifully Rubbed Mahoajsar Finish. 7x11 ».» Tatl 7x24 14.M .4th yovr dealer for the K.O. Typo. R. C. MILLS M East Ord S treat New York Qtjr Let the Radio Quiz Book answer all your question* about radio. Tliis book contain! 260 questions and answers— detailed description! of radio equipment and how to take care of it, and explanation* of radio terms, symbols, diagram!, formulae tabl-e, law*, refutation*, etc. It is • book of ready reference everyone intereated in Radio should have. Send for the Radio Quia Book today. For a abort time we are selling it for $1.00. Mail letter with 25c now I NATIONAL RADIO INSTITUTE, Dipt. R.W. IMS Pennsylvania, Ave., N.W, Washington. D. C American Radio Stores TUBE SET 1 Rheostat 1 W. O. U Socket 1 W. D. It Tubs 1 Grid Leak ConoWassr I "B" Battery. 22 H volts 1 "A" Battery, dry ceil 1 y_eriecoupier I "IV Plats Csndsnssr Wire for Hook Up Free 1 Panel. A* m pa Hoek-Up Only Given with Set jlj.jU Crystal Set' Complete, 'testsd. List SUM. Special PM Federal Set with Phones. List tOM, Special LOUD SPEAKERS Western Electric, Complete tlrUS Maena vex MM Paths IMS Jolley Phono U.M Woodehora 1 M VARIOMETERS Baldwin 14. St Emeo Moulded *-** Queens Ut VARIOCOUPLERS Emeo UT f5.es Baldwin W 1.7S Queens W I N R. M. C, 1M-4M IM All Wave (Csplul) 7 St Multi-Wave (Cardwell) IM American Radio Stores 235 Fulton Street, New York City All orders must include postage. A B C of Aviation Br OAPT. T. W. PAOB. This keek onvrlse* kks keels nrtaetples ef srlstlon. tela hew a balloee er •Briflbls at suds and why It Seate la tke sir. Desirtbss bow en simians He It skew* la *e- tatl tb* different sens or *a airplane, west tke? at* aad wkat tear as. Pastrlsts all trees at slr- plasw and bow thsy direr la eoeetreeUee; as well as dstelnae the edvanUfes sari dteadraataxee at onTareat trpee ef aircraft. It leeludea a sssa- ***** dletieaaiy sf ertatloa terms aed riser drew- aass ef readies airplanes Tb* Mto will lad Sean Is laetreeUeae fer tinpaeslns. settles ep aad nsVtac atrelsses. A full dseerlptea ef alrplsae eaatreT erlselplej Is fires aad aretksae at trust are dUeessed at lenstb. li* keek answers every qesstlsa see sea ask sheet arsders aircraft, their sseeuasus* aed seeee- naa. Sft eases, lit sperUOr saade IHueteeueee wtrk r pletea. Press. II. I* THE COLUMBIA PRINT Mew York Ctts> Answers to Readers (CoMfiMKfu' from page 19) 1. In January 27 issue of Radio World you published an article by John Kent. Where are the phones to be connected in the diagram t 2. How many volts should the A bat- tery bet 3. What is a jackt 4. What ohmage should the phones bet 5. How high should my antenna be in order to get good resultst 6. How far is it possible to receive with this sett 7. What is a verniert 8. Which should be the positive and nega- tive connections on the batteries? 9. How high will this set tunet 10. Can a loud speaker be used with this sett— Antony Loscalco, 327 East 12th St., New York. 1. The phones are connected at 6 and 9 in the diagram, by means of jacks and plugs. 2. The A battery should be V/, volts. Connect 2 dry cells in parallel for this cir- cuit, so that each tube will get VA volts. 3. A jack is a mechanical device which makes it possible to connect and disconnect the phones, without changing wires, or using any switches. They are made in single cir- cuit, double circuit, single circuit filament. The last mentioned automatically shuts off control, and double circuit filament control, the current from the filament when the plug is disconnected from the set 4. There is no set ohmage for phones, but either 2000 or 3000 ohms is the most popu- lar, and is recommended. 5. About 50 feet will be O. K.. but ft is not absolutely necessary. Good results have been obtained wuh antenna strung 10 to 12 feet above ground. Erect your antenna as high as you can, and don't worry about it. 6. You should have no trouble in receiving upwards of 100 miles with this set, if care is taken in the construction, and you have a good ground. 7. A vernier is a mechanical device which makes it possible to obtain very minute and fine adjiis'.ments. In the case of a con- denser, it is generally an extra plate, which is operated independently of the rest of the movable plates, and with which it is possi- ble to get much finer adjustment than by the use of the regular plates. Some con- densers have additional attachment on the dial, by which it is possible to turn the en- tire plate section, a minute adjustment. In a rheostat, it is generally an extra turn of resistance wire, worked on the same prin- ciple. • 8. The positive (+). which was omitted in the diagram you mention, should h» the connection on the rteht hand side of the drawine. or the small plate in the d'awing. For the de'ector. it is the tap with the arrow. The filament battery is optional. b'it it is better if the richt hand connection in the drawing is made the positive. 9 With the ordinary variometer, this se» will tune to approximately Hi) meters. 10. A loud speaker can be used with thit set. e e e / have considerable trouble u-ith Irytl interference. I h.ive a H'etfim-h.>u<e R -f combination rece'-.-rr atul amplifier. It ha< been suazested that I n-ake tu-o mils and use condensers and put same in fariUel •i".th the antenna and t/rouml. Mutt I u<r the same size eond-ni.-rs at thote u<ed in thr set. and u-hat 'l-r<u!d be the si-r of the coilt*— Henry l ifer. X"rn-ieh. Com. We refer yon to the artie'e on filter cir- cuits hy Frederick T. Rurrford. in R ,dio World No. 44. dated Jan 27 It e ves a complete description of all coils used a» well as capacities of r. mden-ers. It is not necessary to ti<e two filter rirr-iits in one receiving circuit. One is ait'Ticient. The value of the condenser rapacity should be approximately .001. D X Records are mall* mm. it with 6000 Ohm N ft K Phone. at veer dealer's er s*nri cheek er awnev arc 1 wtn rsall rou postpaid, a pair et these 114. 10 phorMe tar Special Sale Price $7.75 A hlxber ohm*** than an* oUtar yhm: Ernest Walker Sawyer i «*< M East 4M Street New York refunded If phones sr* net sstlsfsctery aed are returned elthla Art dsn. =Fifty Per Cent Off = Crystal Recervinsj Outfit, worth $s.oo $ Federal Receiving Set, worth $25.00 10.00 Double Slide Tuning Coils, worth $2.00 75 Arkay Horns, worth $5.00 2 SO mi ot r ruMTt-rr usr NEXT WEEK Radio Distributing & Auto Supply Co. CM W. MTU ST. NEW YORK CITY "The Little Wonder" FOR BOYS AND GIRLS CRYSTAL SETS tmblmd-Nwt $|.75 Catches distinctly everything broad- catted within 30 miles. We also manufacture the "Little Wonder" assembled set to retail at $4.00. GUARANTEED TESTED CRYSTALS Galena 7 He Radioelto 8 He Dealers and Joefcere Write far Free Cnlalssj It lists all our radio parts and aapptlaa. Holloway Elec Supply Co, Inc. 238 Third Ave. New York City RADIO BROADCASTING MAP Foa tke sessei at skees talmenl a* BeSse and tke** eke are assasrta* Unites. Bead Bh.Ntn, a eeewenr hen prepared a eektl •atlea seeialale* a wealtk of UeetveeOee at crestesi .slve It skews le tke a at*s war the nf tee ask*** ft.es lh.tr .*.wfV.'loe. the tell lenatks. ewesrefcip. tie. ef seem, Bessyass • ■- - • ■• le ret tke aulseaat pirn aed «tjo,ni.«t tt*m R..Mo srtowkj ha*s a I M.Nell, Be lle Map at l'ntt«a Steles. It le I The IUM MaWslW ki : - Msp ef retted J - 1 S * Irarkee Is tie* The leterJese ef I las sullen, sr* *» b» dlelrwtl.s seMi Tee rell t.tt.rs «f eerh ,tstlon in fl.ee. awe Um leaeue J eerk Tk. iu •:. KleinMs wtta iwkn are tt^m: le r»l and the R».n» Belar Pile — are la blee. Tire, sons* are tiwlwteo. aieke- keilesl lists w stations snd alphsseUeal lane ef sail letters are to V Prlee J5e THE COLUMBIA PRINT I BROADWAY NEW YOU CITY Radio World, 52 Copies, $CJS. Snbacrib now. $SSS a jeer, $XSS sis soonths, $IS three month*. Radio World, 14*3 Broad Digitized by

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28 RADIO WORLD DO YOU WANT TO BUT, SELL OS EXCHANGE RADIO OX OTHER GOODS T DEPARTMENT AT fa A TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS STUCK T— Let me *alv* yonr j charge, Be ar quasi •rick Barber, at Jasper St., Syraoaea. H. Y. HAVE YOU SUN ITT Mr unusual fuRy S- lustrated radio catalog U complete. Only ■ oxesa. W. B. Blatoy. Sprint Grove, Mlnaasots FREE APPARATUS FOR SECURINO SUB- SCRIPTIONS FOR "RADIO." Writ* today for complete lilt of premium! and our special sub- •criptiou offer. "RADIO." Pacific Bldg., Saa Francisco, Cat ASTONISHING RESULTS, ROEAY SINGLE CONTROL HOOK-UP. Don't buy. build or change your receiver until you gat particulara. ROEAY ELECTRIC COMPANY. fiTOOMAB, OHIO. ATTENTION, Araateural! Have you wen the RADIO WORLD'S pace of book-ape in the Oet. 21 inner 15c a copy or start your subscription people an BATTERIES— Edison Storage "B" Battery Elements, 5c per pair: 18 will make one ZLS volt Battery. OILMAN'S BATTERY SHOP, Chelsea Sq., Chelsea, Mass. MAKE MONEY AT HOME MAKING TOTS and nor el tie*. Sand 5c for samples and particu- lara. New Specialty Co., 417 E. 71st St.. New York. This department k intended for everybody who wants quick action on abort annooncemenU corering the bnyiac, hanging or general merchandkioc in the radio field. Readers of RADIO WORLD will find that it pays to read these , New York CM? A COURSE IN MECHANICAL DRAWING— By Louis RouilHon. The author has written a most practical book on the subject of Mechanical Drafting. It fully explains the art of Drawing, Lettering and Dimensioning. It is, by far, the most practical book ever published on this sub- ject, for use In day and evening schools, and more especially adapted for the teacher and for self instruction.' Fifteenth edition, revised and enlarged. Fully illustrated. Oolong. COLUMBIA PRINT. 1493 Broadway, N. Y. C Prtee, tUS. HOW TO BECOME A SUCCESSFUL ELEC- TRICIAN—By Prof. T. C Co nor Sloaae An in- teresting book from cover to cover. Telling in simplest language the surest and easiest way to become a successful electrician. The studies to be followed, methods of work, field of operation and the requirement! of the successful electrician are pointed out and fully explained. 202 pages. Illustrated. Nineteenth revised edition. Cloth. Price, $1.50. The Columbia Print, 1493 Broadway, New York City. FOR SALE— Two step Regenerative Set. Gets 'em everywhere. $100 complete, with tubes and batteries. Jas. G. Wilson, Gen. Del., Box 34, Benson Station, Omaha, Nebr. GUARANTEED TUBES FOR OLD. Mail me burnt out or broken detector and $3.00; your Am- plifier and $3.50, or your W. D. 11 and $4.50, and guaranteed and tested tubes -will be sent. Satis- faction or money refunded. E. Waterman, 192 Ainslie Street, Brooklyn, N. Y. BUILDING A RADIO OUTFIT ? — Generous as- sortment of brass and nickeled machine screws with hex nuts, round, and counter-sunk heads. Just the sizes you need. Sent postpaid for fifty cents. No stamps. Smith-McKinney Hardware Co.. Q if ton Forge, Va. HOW TO REPAIR Vacuum Tubes. Complete literature, $1.00. Box 103, Station C, Toledo, Ohio. ELECTRIC MAGNETS, 98c; Vernier variable Condenser, $1.48. Garth Heckman, Ft. Recovery, Ohio FOR SALE — Regenerative Receiver in cabinet. $22.00. Remler detector panel, with tube and B battery, $12; Remler amplifier with tube and B battery. $12; Murdock 3000 ohm phones. $2.50. All in perfect condition. Robert Van Vleck 116 Chestnut St., Liberty, N. Y. TWO one stage amplifiers. Acme, $8; Remler, $7. Kins Amplifying h orn, $7. Condensers. J B. Rich, Hohiii t. v. ■• V..rk. CASH FOR OLD GOLD, Platinum, Sflver, Diamonds, Liberty Bonds, War. Thrift, Unused Postage Stamps, False Teeth. Magna** Points, Jobs, Any Valuables. MaO in today. Cash seat, return saaiL Good* returned in tan days if you're not satisfied. OHIO SMELTING CO., 3J7 Hip- podrome Bldg., Cleveland, Ohio. RADIO TUNING RODS (Patent Applied For) Eliminates body capacity when tuning fa. With Tuning Rod In your hand you can stop unnecessary noises and shrieking. Every radio hn should have Radio Tuning Rod. Send 15 cents stamps or money order. Radiophone Co.. 505 Fifth Avenue, New York City. STANDARD ELECTRICAL DICTIONARY— By Prof. T. O Conor Sloaae. Just Issued an en- tirely new edition brought up to date and greatly enlarged— as a reference book this work is beyond comparison, as it contains over 700 pages, nearly 500 illustrations, and definitions of about 6,000 distinct words, terms and phrases. The defini- tion! are terse and concise and include every term used in electrical science. 767 pages, 477 illustratioaa. (See page 18 for fuller description.) Price, $5.00. The Columbia Print, 1493 Broadway, New York City. EXCHANGE LETTERS with friends everywhere. Pleasant pastime. Information for stamp Smith, Best tm. M. Portland, Ore. PATENTS PROCURED AND TRADE : REGISTERED— Advice and terms upon i isinasi Robb. Robb A HOI, 1405 Ha una Bldg, Cleve- land^ Ohio; 942 McLachlan Bldg., Washington ADVERTISING SOLICITORS to represeat RADIO WORLD. The beet quick action radet advertising medium. State territory yoo ess cover. Tell us about your past experience. Write Fred S. Clark, Manager, RADIO WORLD, 1493 Broadway, New York. NEWS AND GOSSIP OF THE STAOZ^-Seed 10c for specimen copy of NEW YORE STA the great illustrated theatrical year, $2.00 six months, $1.00 throe fork Star Co.. 14*3 Broadway. N. Y. _____ . . __ EXCHANGE JOLLY, • lERS through our club. Stamp j Betty Lee, lac, 4254 Broadway .New ark City. OLD MONEY WANTED— *X09 to . paid for hundreds of Old and Odd Causa. Easy all old money. Send 10 cents for New Dhtstratas Coin Value Book, 4x4. Yon may have rateable coins. Get posted. We pay CASH. Clarke Cm* Company, Ave. S3, La Roy, N. Y. AMATEURS— LOOK 1 Send in 15 cents to RADIO WORLD for issue of January 20 con- taining panel layout, hookup and full explanatory data on the construction of n D-X receiver, which simply lays the long distance on year table. Or start your sub. with that issier RADIO WORLD, 1493 Broadway, New York City. TWENTIETH CENTURY BOOK OP RECIPES, FORMULAS AND PROCESSES— Edited by Gard- ner D. His cox. This book of 800 pane is the meet complete book of recipes ever published, giving thousands of recipes for the manufacture of vale- able articles for every-day use. Hints, helps, practical ideas snd secret processes are revealed within its pages. It covers every branch of the useful arts and tells thousands of ways of nuking money and is just the book everyone should have at his command. The pages are filled with mat- ters of intense interest and immeasurable prac- tical value to the photographer, the perfumer, the painter, the manufacturer of glues, pastes, cements and mucilages, the physician, toe drug- gist, the electrician, the dentist, the engineer, the foundry man, the machinist, the potter, the tanner, the confectioner, the chiropodist, the man- ufacturer of chemical novelties and toilet prep- arations, the dyer, the eUetroplater. the enanssser. the engraver, the glass worfcer, the gold-beater, the watchmaker, the Jeweler, the ink manufac- turer, the optician, the farmer, the dairyman, the paper maker, the metal worker, the soap maker and the technologist in general. A book to which you may turn with confidence that you will find what you are looking for. A mine of information up-to-date In every respect. Contains an im- mense number of formulas that everyone ought to have that are not found in any other work Vew edition. 807 octavo pages. Cloth binding Price, $4.00. The Columbia Print, 1493 Broadway. Mew York City. WIRING A HOUSE. By Herbert Pratt, a boose already built; tells Jnat how *s start about wiring it; where *a begin; what wire ts usej how to run it according to insurance rules;- is fact. Just the information yoo need. Directions ap- ply equally to a shop. Sixth edition. COLUM- BIA "PRINT, 14*3 Broadway, N. Y. C Prise, VACUUM TUBE RESULTS WITH A CRY- STAL SET I Cover distance with a "FT" ULTRA SENSITIVE CONTACT in your crystal detect- or. Beats gold and other ordinary catwhiskers. DOES NOT JAR OUT. Myrle Wood, RhineUnd er, Wisconsin, writes: "That *PT* Urtra-San si tive Crystal Detector Contact 1 pin phased Is sure n wander. Using the *PT* contort snd galena, I have heard over 43 dnToraot broadcast- tag statkms, up to 1,MS mile* distant. ** The "FT" hat received code 3,300 miles. Price, only twenty-five cents. "PT" CRYSTAL CONTACT COMPANY, Box 1641, Boston. RAND-McNALLY RADIO MAP OF UNITED STATES— It 28 x 30 inches in size. The locations of broadcasting stations are shown by distinc- tive symbols. The call letters of each station are given, also the wave lengths of each. The Radio Districts with numbers are shown in red and the Radio Relay Divisions are in blue. Time tones are included. Alphabetical lists of stations and alphabetical lists of call letters are in the margins. Convenient pocket form with cover. Price, 35c. The Columbia Print, 1493 Broadway, New York City. MODEL MAKING— By Raymond Frands Yates. A new book for the mechanic and ■ode) maker. This Is the first book of Its kind to be pwhtmhed in this country, and all those in teres tad in medal engineering should have a copy. The first eight chapters are devoted to each subjects aa Stiver Soldering, Heat Treatment of Steel, Lathe Work, Pattern Making, Grinding, etc The i twenty-four chapters describe the ccs of various models such aa rapid fire naval _ speed boats, model steam engines, turhineaT etc 400 page*. 301 Oluatrationa Price. $3.00. The Columbia Print, 1493 Broadway, New York Oty- Digitized by_ Google

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RADIO WORLD 29 IF YOU ARE INTERESTED IN RADIO YOU NEED THESE BOOKS RADIO BOOKS THAT HELP YOU Telling How to Operate a Radio Set— How to Build a Set— Principles of Vacuum Tubes and Other Radio Problems RmSo Hook-Up« By M. B. SLEEPER A book that fires you set only |tuu far all kind* of telephone sad tele- graph receiving end transmitting sets, bat simple descriptions of each circuit thorn (or notes oi results oheainod PMCE TSc Construction of New TypeTrans- atlantk Receiving Sets By M. B. SLEEPER There is s peculiar fascinstion about re- cti Tine radio messages from the high- power statioas of England, France, Ger- many, Russia and Italy, as veil as those located in the Pacific Ocean and the Orien- tal conn tries. Several types of simple re- ceiving sets for this purpose are described; with detectors and amplifiers to accompany them. Suggestions are also given for oper- ating relays and reproducing the signals on s phonograph. Schedules of operating time (or high-powered stations are given. la addition, there is some valuable data on home-made wavemeters for testing and ex- perimenting .PRICE T*c Wireless Telegraphy tod Tele- phony Simply Explained Br ALFRED P. MORGAN One of the most complete and i aive treatises on the subject ever g A study of its pares will enabl master aD the details of the wireless trans- mission of messages. The author explains in simple language the theory and practice of wireless telegraphy and telephony. 154 pages, 156 engravings PRICE Design Data for Radio Transmitters and Receivers By E I The only book that give) for designing, receiving apparatus so that you m of mathematics. It'i ind transmitting ad no knowledge first book a " (inner buys after he has learned the use of his phone receiver PBJCEJe^ Construction of Radiophone and Telegraph Receivers for Beginner By M. B. SLEEPER The man who wants to feel the real thriD of accomplishment, and who is not satisfied in the merely making use of what ethers have done for him, builds his own radio apparatus. Radio men can follow the data in "Radio Phone and Telegraph Receivers" with full confidence, because each piece of apparatus described wss first made, tested and found efficient before the final design was accepted. Special receivers, both crys- tal and audioa. are shown in detail. Regen- erative circuits as well sa audio and radio frequency amplifiers are iescrfbed with clear photos, diagrams, snd working draw- ings prepared especially for the novice and the man who wants to receive the radio telephone broadcast A special feature is the phonograph type radio set and the loud speaker. Fully illustrated PRICE Wc The Radio Experimenter's Hand- By M. B. Throughout the prepsrabon of this beak, one purpose was kept in mind— Answer the Practical Question ■ of the "Novice,'' of the "Beginner, and the more advanced "Stu- dent." This book will help in the selection or construction of simple apparatus for the transmission snd reception of radio tele- graph aod telephone signals. In the chap- ters en radio receivers tne simpleet crystal, the simple eudioo, snd the regenerative types are described in quite some detafl. The question of antennas, both far trans- mitting and receiving, are taken up. A good many helpful aurgestioos ere given which will be of conaidcrahle aid to the experi- menter. 16 chapters- Fully i [rostra ted. price turn The A B C of Vacomn Tabes Used in Radio Reception By E. H. LEWIS Written particularly far the person whs would like to gain sa undentandnsg of aba elementary principles of operation of vac- uum tubes and various circuits hi whiah they are used far the recaption of radss- Ulegraph signals and radio- telephone masse end speech. Dluetrated -PRICE gUt Books on Electrkity ArttsasaaWttt Sf USwssftSl^s Br nor. V. 0*OONOB BUMJfB. a imtlsil Made* oe alaaMaal aeasaUUsne at an kiads is- deaed ts a serial af relea. an at las atasjiaat tmm. sod laeamas asir nitlasu efttamtsis; me* rets llliartratad Br em at am srartleal milihsu wise detailed eeistlm af eaah ass. Tata seek la eaauas ras nest ami wares —sussed es the 1 aMrtefes. esterase, as It asm Bw arise ef ilttlrltlty la a stem at ami win ras ssuetlm «t them was are est fansBse with elreenaau fersmlaa MS sscee Nee Bs- Bdldee. pries, tl.M lee. bsudiac and ■alateasaa tf _.. maws be* Is liuli trsebka sad see nam; eeeneas was faaaae wuh ayesaae i tale rtfui eeMau. Prtae, It By BDWABD TBBTBBT. TMs ratemi dees ereetleal ewesaem far aafldlae s ass M. P. brasawsf the Bdtam tne msaate sf BawsaM sbast efty swam auam af the II van mm. m eddttlea. It sitae 4U«rtteee far katlout nee ad elaMrte Mare etrucUas of a euspfe far re— lad eieetru lOi far Pries. II.SS •wart s Fifty Wart f»mni Br ABTUUB J. WaaTX) a meerlae la detail ras ras eatli* km ea aaeeot af Bfty ejaiis: earn mad w e water u win dries s swell era stem sr Maw It ess he aaad as drtte s at a 1st rsaahroe an see end all areuar? wars. The Beak is Uhes- wiia an rasa stitr artatsal eacn an the satesl imstrUm « ras duTerem II.M Aaty of Tmm Books Smut The. U Books for S1SJS, to Ott or address THE COLUMBIA PRINT ROOM 328, NO. 1493 BROADWAY, NEW YORK Digitized by Google

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30 RADIO WORLD Credit Where Due I have received Radio World in which you printed my little article. I did not in- tend to convey the impression that the hook- up of which I sent diagram was original with me. It is one used by the Electrical Research Corporation of Chicago. If neces- sary, or expected from a standpoint of cour- tesy, kindly give the credit for the hookup to the proper persons. The only thing original about the set is in the variety of in- struments used and the method of incor- porating them on a panel. Your truly, H. H. FULLERTON, Waterbury, Vt FREE DIAGRAM AT YOUR DEALER of the Fleboelling Super Circuit FRESHMAN PRODUCTS Especially Adaptable for this Circuit VARIABLE RESIST LEAK With .00025 mfd. Micon Condenser Combined . . . Without Condenser $1.00 75c S Cm Ai FtfCSHf^AN CO lm ANTENELLA No antenna or Atrial needed. Eliminates all the lnraiiTenlencee In radio; operate! fromflt O AA any light socket Prtee only ibmm 1 '"cap. • m-r,- H t*ATC*fTS WMOIH* "MICON" .006 Mica Condenser .001 Mica Condenser $1.00 40c OTHER "MICON" SIZES Bin Prim .00035 $0.35 .0005 .35 .002 40 Bile Prlee .0025 $0.50 .003 .01 .75 I. SO At your dealer's — otherwise tend purchase price end you will be supplied without further eharte. A dia- gram of the Flowelllnt "Super" Circuit tent Iroe if your dealer caa't supply you. 97 BEEKMAN STREET CHAS. FRESHMAN CO., INC. NEW YORK CITY 185 GREENWICH STREET NEW YORK, N. Y. TUBES IN STOCK WESTERN ELEC VT1 DETECTOR UV 200 WESTERN ELEC. VT2 AMPLIFIER UV 281 PHONES Brood si Superior Original Baldwla Orlilaal Slagle Baldwin Now Murdoek. 3000 Ohms $5.50 8.13 4.50 4.2* CONDENSERS, ETC Blooper. 23 pi. Vernier $3.75 Sleeper. 43 pi. Vernier 4.45 Eagle Moulded Genuine Bakellto Vario- meter • 4.S8 Eaolo Moulded Soaulno Bakellto varto- coupler $.23 SLEEPER RHEOSTAT, Lilt Prion, $1.00: OUR PRICE* 29 W. O. II TRANSFORMERS A V $.25 BRISTOL LOUD SPEAKER. . $18.00 CROWN TRIPLE COIL C4 25 MOUNTINGS 0?O^O Heneyeomb Cello In all tine. • ENO MONEY-OROER, INCLUDING POSTAGE— ALL G00O8 GUARANTEED STANDARD RADIO APPARATUS mm Wss Every item listed in this advt. is guaranteed by us to be new and in original cases. Our guarantee of satisfaction or money refunded still prevails. BARGAINS EVERY DAY . vUi'./ ■ — -3 *» w- < SUNBEAM Dletooraph Loud 8peaken $15.00 Dictotraph Phonet 5.(0 Federal Phonol 5.25 Brandei Phonet 5 *0 $7.50 Murdoek Phonet, No. 57. 3000 Ohms 4.75 Radio Corporation Transformers U. V. 712 5.80 Rodio Corporation Tranformers U. V. 1714 5.45 Federal Potentiometers 1.40 Klosner Vernier Rhoostate 70 Flbgerald Rheostats with dial. .76 Cutler Hammer Vernier Rheo- stats 1.25 Cutler Hammsr Plain Rheostats .85 Radio Stores Variable Con- densers, Balanced Shaft Bakelite Ends with knob and dial. 43 Plate 4.10 23 Plate $.75 Koehler Condensers — 23 Plete Vernier $3.50 43 Plate Vernier 4.00 A. B. C. Condensers — 43 Plate 2.25 Baldwin Phones. Type "C"... 8.50 Master Baldwin Loud Speaker Phone 5.50 Acme Transtormere 4.25 Columbia Moulded Varlometere. 8.85 Anderson Glass Enclosed Vari- able Condensers lor table or panel mounting. 43 Plate 2.75 23 Plate 2.35 Triple Bank Wound Coil for N. A. A. ISO to 3080 meters. Silk Wire on Bakelite Tube $2.75 Hook-up using this coil, which has brought in Havana, furn- ished upon request. MONEY ORDER OR OERTIFIED CHECK MUST ACCOMPANY ALL ORDERS SUNBEAM ELECTRIC CO. 71 THIRD AVE. (Bet. 11th and 12th Sts.) NEW YORK Farm Lighting Plants at Bargain Prices. White's "Varioment" Cement Make your owa cello. Construct varlametors. rarle- ceuplers, etc. No distributed capacity. Holds wlaaV inos securely and permanently. Send 25c. tor sample bottle WHITE RADIO COMPANY 123 East 23rd 8traet No* York Ctty GALENA CRYSTAL mounted In special prepared metal 80c. 25c. All guaranteed. Manufacturers, dealers and Jobbers write for quantity prices. We also manufacture Radio parts to order. PRECISION TOOL & MFQ. CO.. 102 Lewis St.. N.Y.Q. First Radio Music for An Indian Dance TROY, N. Y.— Sioux Indians to the num- ber of 160— many of them ex-warriors of the Custer Battle of June 25, 1876, and a number of former Carlisle, Pa., students- gathered one evening last week at Lone Eagle's ranch at Winnett, Montana, and danced to music of the Rensselaer Polytech- nic Institute Students Orchestra, broadcast from radiophone station WHAZ at Troy, N. Y., approximately 2,500 miles distant And at the request of Lone Eagle — who discovered when he first "listened in" a month ago that "Big Chief WHAZ with the Mighty Voice" could be heard clearly three- fourths of the way across the continent — the Students Orchestra played "In the Land of the Sky Blue Waters" and other modern Indian airs for the entertainment of the descendants of the first Americans. It came about thus that the oldest engi- neering college, which has developed the an of broadcasting to the furthermost reaches of the continent from Alaska to Panama in a few months, provided radio music for the first time for an Indian dance last month. The Troy Polytechnic inagurated this win- ter an international radio program from midnight to 1 :30 A. M. on the second Mon- day night of each month. Immediate response came from remote points in all the Western States, Canada, Alaska, Mexico, Cuba and Panama. "Hard and Soft" Vacuum Tubes WHY are some vacuum tubes termed 'hard" and others "soft"? A "soft* tube, the type recommended for use as a de- tector, does not have a high vacuum and contains some gas or gases. So explains the New York "Times." The "hard" tube, used as an amplifier, contains a high vacuum and requires a higher B battery voltage for successful operation. The X-ray developed the terms "soft" and "hard" as descriptive of vacuum tubes. It has been explained by X-ray specialists that a "soft" X-ray tube contains gases and produces feeble rays. A "hard" tube has a higher vacuum and requires a higher plate voltage for its operation. The rays of such a tube are very penetrative and are known ai "hard" rays. The "soft" detector tube gen- erally requires 22J4 volts, and the "hard" amplifying tube 45 to 60 volts, B battery. Complete List of Broadcasting Stations "D EADERS of Radio World will be in- AV terested in the fact that a complete list of all the broadcasting stations has been prepared in the form of a handy booklet, showing all the particulars of the stations. It can be had for the asking by simply send- ing a letter, enclosing your address and a two-cent stamp to cover return postage, to Modell's, 58 Church Street, New York City. It is a most complete little volume and there are many amateurs who can use it. On Thursday evening, February 22, the WGY Players will produce William _ Gillette's melodrama. "Secret Service." Digitized by VjOOvIC

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RADIO WORLD WALCON Radio Frequency Transformers Bring;* In distant stations on a loop— perfect reprodoctiea. W» distortion. THE BEST YOU CAN BUT WALCON Transformers are tested an adapted for nse with W.D.ll tube*. Fonr new hook-up*. Including* a new without charge with each transformer. Price, $4.00. We pay postage. Dealers and jobbere: Write for our attractive sales proposition, bached by national advertising. Manufactured by THE RADIO CENTRE, 2 W. Broadway, N.Y., N.T. Radio Perfection Ajax Socket Rheostat A combination V-T Socket and Rheostat for panel mounting. En- tirely eliminates separate leads be- tween socket and Rheostat and provides a panel-mounted socket without the use of additional brack- ets. Simplifies the installation and hook-up. Strongly constructed. Me- tal parts heavily nickel-plated. Type A-l, 5 Ohms — with knob and pointer, each $2.00. Type A-2, 5 Ohms— $4 inch shaft without SO-00 dial, list each is attained only by the use of mechanically and scientifically perfect parts. Now, more than ever, when the mar- ket is flooded with inferior goods, one cannot be too careful in the selection of standard, trade-marked articles, and in purchasing from a reliable source. It is our aim to supply the highest standard radio specialties, thus insur- ing perfect results and satisfaction. Every article we sell is unconditionally guaranteed both by the manufacturer and this organization. FREDERICK H. PRUDEN Incorporated 993 Bergen Avenue Jersey City, N. J. DO NEARBY NOT BE CONFINED TO LISTENING IN ON THE RBY STATIONS, WHEN BY INSTALLING THE Genuine and Guaranteed Capitol "ALL WAVE" COUPLER (Trade Mark) in your set you can receive remarkably clear and selective broadcast entertainment from Stations THOUSANDS OF MILES AWAY and on any Wavelength from 150 to 3000 Meters without the use of variometers, vario couplers, and loading coils. Patents Granted Eventually— Why Not Now? If your dealer cannot supply you, send us your order and remittance to- gether with his name. Price $g.oo Beware of Imitations Look for the Trade Mark "ALL WAVE" on the rotor, and the six efficient hook- ups packed in every box. Six efficient and simple hook-ups sent free upon receipt of ten cents to cover cost of mailing. Capitol Phonolier Corporation 60 ^YoV1"' Radio a Blessing for the Shut-Ins SURROUNDED by snow from twenty- five to thirty feet deep, and in a country reached but once in six months by mail, E. E. Carter writes WGY, the Schenectady radio station of the General Electric Com- pany, that the deadly loneliness of the past has been dissipated by music-laden waves which nightly pass his antenna. He gets each day's news as early as the man in the city gets his ; the voices of men and women in song and speech seek him out, and the music of many instruments penetrates his cabin walls. The man in the city has the choice of many forms of pleasure; his radio set is a diversion for the "evening at home." There are many lonely men and women who have no choice of pleasures, and for whom broad- cast music is the only relief from a monotonous existence. Every broadcasting station receives letters from the lonely people of the country, who find it difficult to express the pleasure that has been put into their lives. WGY has received letters from bedridden people, who say their only relief from suffering comes during the hours of radio reception. In addition to the invalids who have been imprisoned in a single room for years there are the patients and inmates of institutions, as well as those confined behind stone walls and barred doors and windows. Then there are the lonely men whose work keeps them from centers of popula- tion and attendant pleasures. Keepers of lighthouses and lightships along our sea- coast, fire and game wardens in our forests and on our mountains, and men in lumber camps and in mines. Mr. Carter, referred to in the opening paragraph, writes WGY: "We are located well away from all elec- tric disturbances and at an altitude of over 7,000 feet. We are about fifty miles north of Payette Lakes and well back in the mountains. We get mail only by dog-team and only about once in six months, and have from twenty-five to thirty feet of snow. Radio service such as yours is fully appre- ciated under such circumstances." Mr Carter is located at Holte Mine, McCall. Idaho. H. L. Thomas, a lighthouse keeper at Cape Poge Light Station, Edgartown, Mass., writes : "I am writing you with a great deal of gratitude and pleasure. I am a light keeper, and am classed among the shut-ins. We look forward to your Sunday services, and enjoy your musical programs, espe- cially the dramas. We are located three miles from a small town and are practically alone all of the time, and the radio has indeed proved a blessing." National Radio Exhibit Planned exhibit commencing with the first efforts of the human race to communi- cate with each other and extending down to the latest inventions in radio transmit- ting and receiving apparatus is being planned by the U. S. National Museum at Washington, D. C. Through the co-operation of the Signal Corps of the Army, experts of the Museum are outlining a series of exhibits showing the development of mechanical means for transmitting intelligence. Starting back in the days- of runners, the series of models will illustrate the mounted messenger, the postal service, visual signalling, the helio- graph, wire communications, and finally the modern methods of radio telegraph and telephone communication. Many of the exhibits will be^rstual pieceswof apparatus 'ufliX1]^0^ will shbHieigia^feall^^V^sf^1^ develop- ment of our present communication mt»,c

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A D ! O WORLD T?T>T?T? ADVERTISING T70T717 r MK^EjEj prize contest r 1\>EjEj FOR RADIO FANS FIRST PRlZEr- $250.00 Radio Set Free Six Tube Radio-Audio Frequency Set SECOND PRIZE— $150.00 Radio Set Free Four Tube Set, Detector and 3 stages Amplification THIRD PRIZE— $100.00 Radio Set Free Three Tube Set, Detector and 2 stages Amplification To advertise our business we will give the above prizes to the three persons sending us a list of five or more names of Radio fans and who compose the best slogan or phrase of words we can use for our advertising matter. We are interested in sending our catalogue and price lists to Radio fans. If you are interested in Radio and in its future possibilities don't overlook this oppor- tunity to get acquainted with us, secure low prices on your purchases and an opportunity to win one of the above prizes free of charge. In the event of two or more persons submitting the slogan fudged the best, second best, or third best, each will receive the full amount of the prize tied for. All entries must be received by us not later than March 31, 1923. We retail at wholesale prices. Lowest prices on standard radio groods in the U. S. A. THIS WEEK'S SPECIALS VERNIER CONDENSERS HEADSETS " 2"£ Hf* ^2" "55" *MI am Obm, equala beet HIM phone, on marital, now.... KM Z3 Plata ».**, Cel ni.niln Teal flhm CDJ m Di-._ m m « M r a* niiiiiaw leva unm *m 43 Plata .* " *M, - %m Freshman Grid Laak and Condenaar for '. , , . — , _ FlewaUnc Circuit " LJ*. » .ft Federal Ml VERNIER RHEOSTATS VARIOMETERS Thordaaen Llat tut, now tljs „_ Kloanar " l.SS, " lja Atwatar Kant I»* National " lJa, " 1M Moulded ** VACUUM TUBES Jr" TrP* '. X U. V. 2M Dotcctor I4j» v r m fatmT, " " S VARIOCOUPLERS WD-U JH TVoh^. «JS Moulded H» B*^** ^ 2£ tap3c.r&, ^.r1*"^ *~ to TRANSFORMERS PANELS Thordaaan Li.t WJa, now $*JI Hard Rubber. U. S. Navy Spedncadona, per aquar* Atwatar Kant *' " » inch fails Acme " M» BakoUto, par aquare inch M WD-ll " SJ". " «* 14|*\\1/ Tf\ ADnrD All foods forwarded by Parcel Po.t. Send Money Order with order, and nV/VV 1 W VSIXaLFI-elX include the following- rate* with came for portage: On Purchase* $1J0 to $5.M, 6 Cent* Pottage On Purchase* $10j00 to $20.00, 20 Cent* Po*tage On Purchase* $5.00 to $10.00, 15 Cent* Postage On Purchases $2Sj00 to $50.00, 35 Cent* Postage Space being limited, we are obliged to omit other money-saving items. Write for quotations or ask for our latest Price Sheet Catalog. National Radio Products Corporation MaiLflwier Dept. 509 FIFTH AVENUE _ NEW YORK rrpzed by V^OOgle

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15c. March Year SZ Numb WORLD RADIO HOUR ABOARD SHIP h ip a ti n ft I(C Photo Newt) Many Urn** whlk a ship U In la the old days, thay, of course, would go "i of stylo. It Is hard for port tfaa officer* and have a JACKIE PHONES lot of tiaao oa 'K»lr hands but atneo Mr. Volstead baa put "the corner" out of stylo. It Is hard for some of them to FiD the w-sry brurs. la that case, they Just go up and "listen In" to the many programs that are betas be adcast from the various • tattoo* This photograph shows Operator H. Gilder and T. Kno» listening to the Snday sermon broadcast from St. Thomas Church, while the 3. S. Marantic lay m part. V letting the operators has coma to bo quite an institution of lata, U reports circulated to that effect hold any truth, and It certainly must be a : i«ur» to listen In when apparatus such as shown herewith can be used. The aet Is of English make, and, as can be seen, utilises t rubes, which are quite different from those of American make, roeembmg an nvei grown glass grid leak more than anything, but they are said to be wonderful detectors and amplifiers. Knox Is seen tuning In. ((' Kj.lcl and Htttxrt) One of the recent treats for the astenmg public waa an address over the radio telephone by Jackie Coogan, the world's highest paid juvenile star. The talk was given from the broadcast- lag station WOR of l_ Bamberger • Co., New- arli, N. J. Master Coogan gave a very mtar- esting talk to the boys and girls, and was literally flooded with letters m answer to the request made over the phone that all who heard should communicate by letter. The md- dent impressed Jackie so much he Insisted that his father buy h-m a radio outfit so that be could hear the str**i»» and news of the day.

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KADtO WORLD TT"PT?1? ADVERTISING T?"P"I?T? r _YJL*f__f PRIZE CONTEST " JVC* FOR RADIO FANS FIRST PRIZE— $250.00 Radio Set Free— Six Tube Radio-Audio Frequency Set SECOND PRIZE- $150.00 Radio Set Free— Four Tube Set, Detector and 3 stages Amplification THIRD PRIZE- $100.00 Radio Set Free— Three Tube Set, Detector and 2 stages Amplification To advertise our business we will give the above prizes to the three persons sending us a list of five or more names of Radio fans and who compose the best slogan or phrase of words we can use for our advertising matter. We are interested in sending our catalogue and price lists to Radio fans. If you are interested in Radio and in its future possibilities don't overlook this opportunity to get acquainted with us, secure low prices on your purchases and an opportunity to win one of the above prizes free of charge. In the event of two or more persons submitting the slogan judged the best, second best, or third best, each will receive the full amount of the prize tied for. All entries must be received by us not later than March 31, 1923. We Retail at Wholesale Prices. Lowest Prices on Standard Radio Goods in the U. S. A. Our Peanut Tube Does the Work of W D -11 For Detector and Amplifying uses. Can be used on 1 Va volt dry cells or regular 6 volt A Batteries. Fits standard V.T. socket. Uses about 1/10 ampere, on two V/2 volt dry batteries. Price of tube, $2.50, includes adapter. V/i VOLT TUBE (not WD-11, but for same use) $5.00 THIS WEEK'S SPECIALS VACUUM TUBES HEADSETS U. S. Navy (Pliotron) tuad as a detector, amplifier and transmlttine; tub*, all in e, type V. T. 14. List IMt, now $4.4* Z2M Ohm, equal* beet $444 phonee on market, now Ha __ , _ . ..„._,.„,.„,__,_, Brsndea-244* Ohm Ml u. v.'ai* Detector.. ...".rr.'TT'....."."JS 5lcJto*7ph •._ ** U. V. 2*1 Amplifier MS Federal Ml U. V. 241A Amplifier 154 ____.._ wo-" in voit VARIOMETERS vunnhurnain Detector 4.25 Cunning- ham Amplifier S.2S Atwater Kent HJS My ere Audi on Hifh-Mu 4J4 Moulded 4JI Vacuum Tubee Repaired. Broken and burned out tube* Jr- Type "* repaired. Mail them parcel poet Insured. Price. K.7S each, Baldwin 4JI each with your order. Tubee returned by Parcel Poet, pre- paid. We guarantee them to burn equal to new tube*. VARIOCOUPLERS VERNIER CONDENSERS Mould* km U Plate Uet Ret, now 8.M iT"V*T < -r ~! _ Plate " $.t», " 4.44 Fischer, Jr., Type Mi 43 Plate 4 54, « S.44 WD-11 Adapter. U»t $1 .44. now »».J5 Freshman Grid Leak and Condenser for FleweUinc Circuit » L*4. " .75 TRANSFORMERS PANELS Thordaeen Uet $4 St, now SMs Hard Rubber. U. S. Navy Specifications, per square Atwater Kent " M*. " MS inch S4.415 Acme " M4, " Ml BakeUte, per square Inch .42 WD-11 " SM, " Ml f TfV\l 7 Tf\ /"iDTlITD All foods forwarded by Parcel Peat. Send Money Order with order, and llW W 1 \J VSIxJL/EsiV include the following rates with seme for postage: On Purchases $1.00 to $5.00, « Cento Postage On Purchases $10.06 to $20.09, 20 Cento Postage On Purchases $5.00 to $10.00, 15 Cento Postage On Purchases $25-00 to $504)0, 35 Cento Postal* Space being limited, we are obliged to omit other money- saving items. Write for quotation* or ask for our latest Price Sheet Catalog. National Radio Products Corporation Mail Order Dept., 509 FIFTH AVENUE NEW YORK Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered as second-class matter, March 28, 1922, at the Post Office at New York, N. Y., under the Act of March 3, 1S79] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone; Bryant 4796. Vol. II, No. 23. Whole No. 49 March 3, 1923 15c per copy, $6.00 a year Intricate Receiving Set Embodies Both Crystal and Tube Detector ONE of the features of the amateur contest at the Perma- nent Radio Fair at the Hotel Imperial, New York City, and one which created much interest, was a minature set so small that it was easily held in the palm of the hand and yet was a most complete receiving set. The set embodies both a tube and crystal detector, either of which may be used at the operator's desire. The set proper consists of spider web in- ductances, the relation of which is varied in a sliding motion, somewhat like sliding doors. The inductance is varied by a tiny switch, and has 13 switch points. One of the detectors used is a regulation WD- 11 with a specially made socket which takes up very little space. There is also a crystal detector, to be used for local work and when batteries are not available. This set is so extremely small and compact that it is a constant source of wonder to the layman that it can be made to work. But when the set is closely examined it is found to have been constructed with all the care that a watchmaker would take in making a small wrist watch. When the small space that the maker had to use in the construction is taken into consideration, it surely is a wonder that any man had patience enough even to attempt to make such a small machine. Its excellent receiving qualities were demonstrated, and although an allow- ance was made for the smallness, won- derful results were obtained. This set is extremely efficient on short waves due to the fact- that it is so compact that short leads are possible. This set is one of many which va- rious builders have made to illustrate the fact that a set does not have to occupy half a table in order to work successfully, and is one of the smallest and most compact yet seen. Of course, this small set while practical, cannot be expected to accomplish the work of one of its larger brothers. These minia- ture sets seem to crop up overnight, and more models will be shown in these columns in the near future. By Louis S. bidder (C. Photonews) One of the moat intricate miniature radio receiving seta made by an amateur. The set is equipped with both crystal and vacuum tubes, as can be seen In the photo. Tuning is accom- plished by sliding the spider web inductances and by means of a small 13 point switch. This set Is extremely small and compact, as can be seen by comparison with the else of the man's Digitized by Google

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4 RADIO WORLD Multitube Reflex Circuits By W. S. Thompson, E. E. IN the multitube reflex sets the importance of the by- pass condenser cannot be too strongly emphasized. There must be a path for the radio- frequency oscilla- tions, or waves, so when using two audio-frequency trans- formers and phones they must be shunted by condensers to make the impedence of the circuit as near zero as possible. The inductance of the windings of the transformers and phones is very high so we must place in the same circuit a capacity to counteract the inductance. This is accomplished by shunting a condenser around every winding that would act as a choke coil. No choking effect will be caused by the radio- frequency transformers because they are designed to pass the high-frequency waves. As we add tubes to our set the precautions taken to pre- vent oscillations must be greater, for there is more chance that one of the tubes will start local oscillations. The proper use of the potentiometer will go a long way towards pre- venting this disturbing factor, but the further precaution of a high resistance in the plate circuits will have to be resorted to in some cases. If the operator can get results from the set by proper tuning and use of the potentiometer Fig. 1. Diagram of a reflex circuit using two tubes with crystal detector. This circuit is equal to two stages of radio frequency sad two of audio frequency amplification. he will not need any additional apparatus, but the grids work best when they have a normal negative potential and in this condition the tubes are very liable to start oscillating. For this reason the author believes that time in tuning will often be saved and results almost equal will be obtained by inserting these resistances. For a high resistance the author used noninductive coils of very fine German silver wire, but has since seen advertised a B battery potentiome- ter that would be of great help for this purpose. The author has not tried every hook-up given, buf is giving them here to enable a reader to pick out the ones that he wishes to try, or the ones, the apparatus for which, he already has on hand. There is nothing particularly new about the reflex circuits for they have been known for some time and have been used by French and English amateurs. The reason we have not used this hook-up or radio- frequency amplification more than we have is probably because there has not been any proper coupling apparatus and because our American tubes have a high internal capacity. To-day there are on the market several very good transformers, so there is no reason why any amateur who is using two or more tubes should not be having the added advantages of two or more stages of radio-frequency amplification. It is a great DX getter and is a static eliminator when using a loop. The loop shown in the hook-up may be replaced by any antennae tuning arranecir such as a single slide tuning coil, variometer. ' ' r. and other parts. Flf. 2. Diagram of reflex circuit using s tube detector. This is exactly tat same as Fig. 1, but a tube Is used as a detector. Fifur* 1 This two-tube set is the equivalent of two stages of radio- frequency amplification, detector and two stages of audio-frequency amplification. Using this set with a loop the signals come in clear and strong with a range that will delight the user. The only additional feature is the use of a by-pass condenser around the potentiometer. This is to provide a low resistance path for the radio-frequency waves in the grid circuits of both tubes. The dotted line in the grid circuit is an optional connection which may be used or not as suits the builder. The difference lies in the fact that if connected as shown the grid potential of the second tube is always negative, while dotted connection would allow the grid potential to be varied. Figure 2 This is a modification of the above circuit using a tube as a detector or rectifier. The tracing of circuits for this hook-up is exactly similar to that of the one tube set. The wave is amplified twice by the two hard tubes through the radio-frequency amplifying transformers, and goes to the grid of the detector tube in the plate circuit of which audio- frequency waves are set up. This plate circuit is coupled to the grid circuit of the first tube by an audio- frequency amplifying transformer and the two hard tubes again amplify the signal, this time in the form of an audio- frequency wave, so a very loud response is obtained in the phones whi-h are placed in the plate circuit of the second (Continued on next page) Fig. 3. Diagram of a reflex circuit using three tubes and crystal detector. This circuit is equal to three stages of both radio and audio frequency amplification. Digitized by Google

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RADIO WORLD Perfect Broadcasting Now Possible By Peter A. Sensenig Dr. Philip* Thomas and his annt invention, die "Glow Discharge" Trans- mitter. Thia device has been thoroughly tested out, and has been found slimitutte many of the ibles that are now at- m I ei as to microphonic The old typo of ophono was the of spnilmg many fine programs, due to the fact that it would pick ■ and magnify aD »w son a I floor. ThW which la thoroughly ex- plained fa the accom- panying text, doea away providee a ' PITTSBURGH, PA.— Millions of radio fans will be benefited by a new radio transmitter invented by Dr. Phillips Thomas, re- search engineer of the Westing- house Electric & Manufacturing Company, East Pittsburgh, Pa. The new transmitter makes possible the broadcasting of music and other sounds exactly as produced. It has been used at the Westinghouse broadcasting station KDKA within the past few months, which explains the clarity and strength of this sta- tion's signals. The basis of Dr. Thomas's inven- ting. tion is the elimination of the dia- phragm now used in all transmitters in practical service. This diaphragm consists of a thin disk of metal or other substance and operates by be- ing vibrated by the sound waves which strike it. But because of its inherent inertia, no material dia- phragm is capable of vibrating in perfect sympathy with the entire range of audible sounds. If it can transmit low notes successfully, it will fail on high notes ; and vice versa. The ordinary diaphragm is designed with reference to the mid- dle register, and it therefore doesTransmitter. not transmit extremely high and ex- tremely low notes satisfactorily. The piano is a case in point. The radio audience hears the highest notes as a series of clicks and the very bass notes as a roar. In the Thomas transmitter, a min- ute electrical discharge takes the place of the mechanical disk. This discharge flows between two points, separated by a very small fraction of an inch. It is affected by sound waves, just like the diaphragm, but being non-material and having no perceptible inertia, it responds equally well to all vibrations. Hence music broadcasted, by means of it, is transmitted in all its original purity. Dr. Thomas has recently been ex- perimenting with his transmitter at the Westinghouse Pittsburgh Sta- tion, KDKA. Listeners all over the country have noticed from time to time the great improvement in the quality of the voice of this station, but have naturally been unaware of the cause. Within the near future all Westinghouse stations will be regularly equipped with this device, and the art of broadcasting will take another step forward. In appearance, the Thomas trans- mitter resembles a large watch, with the front and back covered by wire gauze. On looking into it, a point of light can be seen, caused by the flow of the electric energy against one of the terminals. From this fact it is called the Glow-Discharge (Continued from preceding page) tube. Bypass condensers are used in shunting any high impedance coils as in all other circuits. The signal strengths obtained in this set are as loud as can be obtained unless more external stages of audio-frequency amplification are added. This set is recommended for good, clear, strong signals, where maximum DX is not desired. Figure 3 Circuit 3 is the most popular reflex set that is in use today and is recommended as one of the best sets for the average amateur. It is the equivalent of three stages of radio- frequency amplification, detector and two stages of audio-frequency amplification. Any further addition to this set would have to consist of more stages of straight radio or audio-frequency amplification. In fact, the first tube of this set is used but once, the hook-up being given to enable any reader to build this set if he desires one of the best sets for long-distance work. This set incorporates radio-frequency amplifying trans- formers as have all hook-ups so far given. The results obtained by circuits to follow were not sufficiently better to warrant using them unless existing conditions would make their use advisable or unless some experimenter wishes to try them. l/rtoo Figure 4. Commercial type reflex circuit, using cm stage of resistance, coupled radio frequency ■mpM-rfUi, and two stages of transformer coupled amplification. Plate resistances are shown in the preceding hook-up, and it is recommended that they be used, for it adds to the ease of tuning. The set will be very selective and easy to tune if resistances, variable from 500 to 2,000 ohms, are used. When this set is used with an outdoor antenna the range will be greatest and will depend almost entirely upon the skill of the operator for it is a DX getter. Digitized by Google

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6 RADIO WORLD How I Received the American Signals in France By Marius Thouvais, President Radio Club of Salogne, France THE receiving set which I used during the transatlan- tic tests was not at all designed in anticipation of such DX work. The tuning is effected by means of inter- changeable coils of various sizes covering the whole range of 150 m. to 2400 m. As it stood, I believed it to be far less efficient than a Grebe, a Paragon, or any standard two-variometer regenerative receiver, and I believed also it was absolutely unable to give such a performance. My aerial is not high, having been erected between the chimney of my house and a wooden mast in the garden. It is 27 feet high at each end, and hardly 23 feet in the middle, as the wires stretched three years ago and form a graceful curve now. It is a three-wire antenna, 120 feet long. The lead in is shaped as Fig. 1. The fundamental wave length of the whole is something like 230 meters. This aerial has proved rather efficient, as immediately after the war, when audions were not obtainable, I was able to read, regularly, on a crystal detector, many DX spark stations such as Lisbon, Gibraltar, Bizerte, Malta, Vienna, Budapest, Copenhagen, Karlsborg, etc., and I even picked up the First Chelmsford telephony in February and March, 1920, and always on galena. 37 Meters -It HE 30 leaefm Ttfeters Qutdoor Lead in 7 Meters - Indoor Ground kf/re 5 Meters jret such DX signals, and believed my much simpler material quite unable to receive the easiest test. On the WL 350-450 meter I heard three British broad- casting stations with very great intensity, both music and speech being too loud to be comfortable when wearing the headset, and it could be almost continuously heard in the whole room without any loud speaking device. A little while later, that is, barely a week before the commencement of the tests, I at last succeeded in getting my receiver oscillating freely on as short a wave as 200 meters. I got this result by using a special type of winding of my own design. This type of inductance is somewhat like the well-known spider web coils, but over which it is an improvement The different manner in which it is wound gives a still lower self-capacity and a greater inductance for a given number of turns, thus making it especially efficient for short wave work. As previously stated, I used simple single circuit — a fixed coil in series with a variable con- denser. This method is doubtless less selective than using a variocoupler, but it is really efficient, and is much simpler to manage. With the aerial described and thevariable con- denser in series, a 30 turn coil tunes from 180 to 300 meters, while a 50 turn one covers the WL range — 250 to 500. In either case a 30 turn inductance is quite suitable as tickler coil. Before the tests I had only heard two French amateurs, 8AG and 8AB, the latter extremely loud, although located about 375 miles away. British amateurs, 2AW, 20D and 2YZ, were also received with excellent intensity, as well as several telephones from British amateurs. These results decided me to spend one night in listening in to try if I could pick up anything during the tests. I was not at all confident, to say the least, and it was on the fifth day only of the tests that I tried. During the nights of December 16th and 17th I only was able to enjoy the concerts sent out on 360 meters by several American broadcasters, among which is WJZ. It was on my third night, December 18th, that I caught two American amateurs in addition to the usual broadcasting. It was then that I realized that my set worked much worse on 200 meters than on 360 meters. To remedy this on the following days I built a new variable condenser of the air dielectric type to replace my inefficient paper- insulated condenser. Also, in view of lowering the radio frequency resistance of the whole, I tripled the single ground wire. Immediately my apparatus oscillated much more freely on as short a wavelength as 150 meters, and the efficiency on the band — 180-250 — was very greatly increased. I was enabled to receive ten additional call letters on the following night. The next day, having again found time to improve several details — increasing my plate battery voltage to 80 volts and removing the aerial lead in a little further from the wall — I was quickly rewarded for my trouble on December 20 by picking up not less than twenty-five calls from the United States amateurs within a period of less than two hours. For the last night, being no longer afraid of lack of fila- ment current, I decided to listen in up to the end, and, fight- ing against sleep, I worked continuously from midnight up to and after 5 A. M. (G. M. T.). But this last night was certainly among the worst on which I had experi- mented. The static was very bad and arc jamming at (Continued on next page) Digitized by Google

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RADIO WORLD 7 Radio Broadcasting Station on Wheels By John Kent (C. Kadel & Herbert) Exterior view of the t ravelin* broadcasting station. The antenna i* strung on poles from the front of the radiator to the back of the portable bouse, which serves aa an operat- ing- room, It Is a great stimulator for radio, and numerous people who have never taken interest in rado have become "fans" through die agency of this novel station. Interior of the traveling broadcasting station. Both the receiving and trans- mitting sets are arranged on the table at the left. Current is furnished by the little generator shows in the lower right hand corner. The station Is a fully Hceneed station and operates through the rural district of i WHAT is probably the most unique broadcasting station in the world, was recently built by Horace A. Beale of Parkesburgh, Pa. It is a complete broadcasting and up-to-date receiving station on wheels. It is called the Chester County Radio Association, and travels from place to place in the different townships, giv- ing instruction in radio, as well as allowing the people in the rural districts to see just what broadcasting is. Many people listen to broadcasting but do not understand exactly how it is accomplished. When the "station on wheels" comes around, they have a chance to "peek at the innards" of such a station. As can be seen from the photographs, which show both the exterior and interior, it is a most complete station. The current for the operation of the transmitting set is furnished by the little gasoline engine driven generator, shown in the lower right hand corner of the composite picture. The receiving set is shown in the center of the illustration and as can be seen is of the well known regener- ative type with two stages of audio frequency. The trans- mitter is located directly next to it, with the tuning induct- ance on top of the set proper. It is a tube transmitter, using one tube as an oscillator, and one as a modulator. The phonograph is situated directly to the right of it. The call of this traveling broadcasting station is 301, and is registered as Parkesburgh, Pa. (Concluded from preceding page) times made reception impossible over a wide band of wave- length. The usual jamming from ship and coast stations covered the rest, so that I received only two or three calls during the free-for-all period. The latter part of the final night was a little better. The arc jamming having disappeared, I was enabled to log a dozen more calls. In conclusion, I wish to point out that I listened in six days, and that on the first three my set worked badly on 200 meters. Further, it was only on the last night that I worked for as long as five hours. On all previous nights I had spent only three hours, on account of my attending to business throughout the day. Also, I dare say, that if I had shown more confidence in my set and had started to listen in from the first night of the tests, and if my apparatus had been carefully prepared to work right down to as short as 180 meters, a little while before the outset of the tests, I honestly believe that I should have been enabled to receive most of the stations heard throughout Europe, as most of the calls that I logged were strong enough and^would have been received as well without the second tube, that is, with the detector tube alone. The second audion acting as an audio frequency amplifier is by no means an element of sensitivity. It was only useful on particularly good nights, as it gave body to the signals Fig. 2. Circuit used by Mariua Thouvaie in the reception of amateur signals. The condenser in the antenna circuit C2 is As can be seen, It is a single circuit hookup, and testifies to the efficiency of single circuits in long distance reception. Suggested by M. Thonvais. Drawn by S. Newman. and to some extent facilitated reading, but on bad nights when there was heavy static and jamming it was rather a bother than a help. Digitized by Google

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8 RADIO WORLD Department of Communications Suggested By Carl H. Butman WASHINGTON, D. C— The creation of a Depart- ment of Communications including radio is sug- gested in the report on the Reorganization of the Executive Departments submtited to the joint Committee of Congress by the President a few days ago. The committee, headed by Walter F. Brown, suggests that the Post Office Department be renamed the Depart- ment of Communications and that it include an Assistant Secretary for Telephone and Telegraph, including radio. In the report Mr. Brown says in part: "The only important change contemplated is the addi- tion of a bureau (to the Post Office) to develop and extend telephone and telegraph communications, including wire- less, for the general public benefit." Apparently the Navy would retain its communication system as would the Signal Corps, but it is evident that radio regulation would be transferred from the Commerce Department to the Department of Communications, although the Bureau of Navigation, under which the radio section operates today, is left in the Commerce Department. Although the report is labeled as recommended by the President, his letter of transmittal states that with few exceptions, the changes have the sanction of the Cabinet, and adds that it is his hope that the suggestions will be of assistance to the committee. Further than that, the Presi- dent does not appear to urge its adoption and he has refused up to date to state any of his views on the subject, outside of stating his recommendation. There's a Town Called Radio By Washington R. Service WASHINGTON— Radio is the name of a town in Virginia, just across the Potomac from Washing- ton. It is there that the gigantic towers of the Naval Radio Station, from which the name came, is situated. Usually it is known as Arlington, being near the great National Cemetery, but the call letters of the station NAA are known almost around the world. In the Postal Guide the tiny village at the foot of the three great towers, one of which is 600 feet high, is listed as Radio. This naval radio station was put in operation in 1912 and was the first of the navy's chain of high-powered radio stations to be established. It has only become well known t ) American fans since the government broadcasting was transferred there in January, but today many thousands of radio owners listen in on 710 when NAA speaks. When the station was first put in operation only code signals were sent and received. Ten years ago, all opera- tions were conducted on a single set from a little hut nearBy under the direction of a superintendent of communications. To-day it is different; seven separate transmitting circuits are operated by remote control from the Naval and Munitions buildings in Washington, from which wire lines link up with the radio circuits for both army and naval use. All receiving is done in Washington by special antenna and loops. Simultaneous operation is permitted with six sending sets without interference, thanks to "duplex operation." Back in Early Days WASHINGTON, D. C— Back in the early days, Chief J. W. Scanlin was listening in one night — on Dec. 29, 1912, to be exact. He heard a curious series of numerals and letters forming words unintelligible to him. He had heard similar characters in code for sev- eral nights, but on the night mentioned he copied the message and told his- superior officers in Washington that he had heard and copied "FL." He was laughed at. FL was the call of the Eiffel Tower in Paris, and no one be- lieved he could pick up a message from that distant station. He insisted, however, and a report containing the copied message was transmitted to Paris through the Department of State. The reply proved that he was correct. He had copied Eiffel Tower, and correctly except for a few char- acters. For the first time, an American naval station had caught a European radio station. The message dealt with longitudes, and was sent to a small French expedition in Egypt. It was partly an experi- ment to learn how far inland an expedition could go and copy on a portable set the messages from home. Curiously the message copied nearly got the transmitting officer into trouble with his Government. He had added a personal postscript to a fellow officer on the expedition, which was against the French regulations, but he escaped court martial and is now very near the head of the French Army com- munication service. Soon thereafter experiments were undertaken between NAA and the Eiffel Tower and direct two-way communication was established in 1913. Seven Sets at Arlington With the old 100 K.W Fessenden spark set, put in opera- tion in 1913, some remarkable long distance results were achieved. Naval vessels in the Mediterranean have copied the time signals, which are still sent out from NAA on this set, after nineteen years of service. An amateur in Brazil heard NAA as long ago as 1914, but this is not uncommon today. Some of the first radio telephone experiments were con- ducted from Arlington in 1915 with Western Electric apparatus, and the announcements were received in Pearl Harbor, Honolulu. Digitized by Google

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RADIO WORLD 9 A Simple and Improved WD- 1 1 Receiver By C. Whitey Consulting Engineer NOT so very many months ago amateurs were striv- ing to build as small a radio receiver as possible and still be able to get fairly good results when near a large station. Many of the sets developed certainly were as small as one could possibly imagine a radio set could be, but other than that they were of little practical use. Things have changed and the ambitious amateur is no longer spending his time trying to get miniature curiosities and is, on the contrary, trying to evolve radio apparatus that is capable, under normal conditions, of receiving from distant stations with ease. Not only are radio fans trying to accomplish this feat in designing, but they are trying also to accomplish it in the simplest possible manner. They are not using any very complicated circuits, but they are using simple circuit receivers that are built in the right way. Simplicity is often the keynote to success. In designing and constructing sets it is always good to bear in mind that the fewer the controls and circuits the better the results in the average case. In the construction of the receiver that I describe herewith I wish to call special at- tention to the fact that there are absolutely no switchpoints used, and there are only three variable controls, two vari- able condensers, and the filament rheostat. The tuning and tickler coils are rather small and compact, thus conserving on cabinet space as well as panel space. Nevertheless, de- spite the small size, the controls on this set fully allow flexibility in tuning since they are associated with in- ductance coils that are calculated according to the right size for broadcasting and general amateur work. The diagram herewith illustrates the schematic hook-up. In theory it is very little different from the standard single circuit regenerative hook-up, except in the fact that the coupling between the tickler coil F and the main tuning inductance coil E is not variable mechanically, since the coils E and F are wound together on the same 3-inch tube. However, the coupling is variable from the electrical stand- point by means of the condenser C-2. Hence since C-2 is a small size of condenser it is possible to adjust for the right point of regeneration by a slow movement of the condenser plates. With this type of coupling it is not as hard to adjust to the point where the tube is on the verge of oscil- lating, as in the case with an inductance type where the tube is thrown suddenly into oscillation by the slightest •change of the tickler coupling. The receiver is designed to work efficiently within the .normal amateur and broadcasting range. The best opera- tion is at the broadcasting range ; that is, from 300 to 450 meters wave-length. If it is wished to use the receiver frequently on the lower wave-lengths it would be better -to either tap the winding E at a midpoint or use a smaller •condenser in the antenna ground circuit. The constants for the circuits are as follows: C-l is a 13-plate air variable condenser. C-2 is an air variable of the 11-plate type. C-3 is a mica condenser of .001 mfd. capacity used solely as a bypass for the phones. The grid leak has a resistance of one megohm and a capacity of .00025 mfd. The coils E and F are wound on the same 3-inch tube with No. 22 D. C. C. magnet wire, coil E hav- ing 70 turns, and F, 40 turns. The spacing between the end of E and the beginning of F should be about of an inch, and the total length of tube required will be six inches. It is advisable to purchase the standard type of tube socket and then an adapter for the WD- 11 tube. This will -enable the constructor to change rapidly to any other style •or make of tubes if the owner so desires. It is better to mount the tube socket on a pad of j4-inch felt so as to avoid serious microphone hums that are transmitted to a sensitive dry cell tube when the tube is firmly attached to a metal holder. Owing to the fact that only two dials and the filament control knob are to be mounted on the panel, this set can be easily laid out on a panel 6x10 inches with- out any undue crowding. This set is simplicity itself, and still it works with great ease and brings in results that Veritably make you believe it is a mystery box. It is possible to assemble this tuner complete in a good cabinet for less than $15, because there are no expensive variometers or vario-couplers to be pur- chased. For the man who wants to bring in just the broad- casting stations this set will find no equal for cost and efficiency. With a dry cell vacuum tube it is capable of operating for more than two weeks on a single No. 6 dry cell. The coupling of the coils In this circuit U to produce oscillation is accomplished by Is of small capacity. the variation of the < of the condenser C2, A good reliable make of B battery will last about a year with one tube, if it is not abused. The construction is so simple that a complete assembly can be readily made in half a day. Only three holes have to be drilled for controls, and about three more for peep holes for the bulb. Shielding the inner side of the panel and the cabinet is recommended. If it is not desired to shield the whole cabinet and panel, then it is advisable to at least shield the panel in the vicinity of the two variable condensers, so that disagreeable body capacity effects can be eliminated. The shielding should be copper foil and grounded. To Radioize Atlantic City Boardwalk According to plans of the Western Electric Com- pany, a test has been carried out as to the practicability of broadcasting concerts and operas by special appa- ratus installed along the walk at Atlantic City. This plan would, when carried out and completed, permit concerts given in Chicago and other large cities in the United States to be heard while strolling or wheeling along the Boardwalk. If plans are fully car- ried out, Atlantic City will be known as one of the largest radio centers of the world. Digitized by Google

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10 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming Into Radio Circles Weekly A B G of Radio Facts and Prin- ciples Fully and Tersely Explained By Lynn Brooks T~ T~0W many times can a signal be amplified? r ~i While there is no set number of stages that can be used in the amplification of radio signals, where audio frequency is used (signals amplified after they have been rectified or detected), there is, of course, a practical limit This has generally been set to two or three stages at the most This is because of the fact that when more than 3 stages are used, the inter-tube noises and coupling cause such a great amount of distortion that they often render the signals indistinguishable, and may entirely kill them. In the use of radio frequency (amplifying the signals be- fore they are rectified) any number of stages can be used up to six or seven. Due to the fact that it is extremely ex- pensive both from the operating standpoint and from the initial cost, not more than three stages are advisable, al- though more can be used. * * * Which is the most practical form of amplification? In the amplification of radio signals there are two differ- ent methods that can be used — namely, radio and audio frequency. In the first-mentioned method, the signals are amplified while they are still inaudible to the ear. That is, they are amplified while they are still in the form of high frequency energy. This method allows greater detection strengths, because of the fact that the detector cannot rectify any signal that is inaudible or too weak to be heard after the rectification. Thus it is seen that in order to get better results from a set, it should embody both radio and audio frequency amplification. * * * Is radio frequency advisable with regeneration? Radio frequency is advisable with regeneration, but, due to the fact that the principle of regeneration tends to am- plify signals itself, it is not necessary. In a set embodying both radio frequency and regeneration, there is likely to be a lot of extraneous noise, due to the use of radio frequency and regeneration. Regeneration itself is noisy, and as radio frequency is absolutely quiet, the advantage of the latter is somewhat lost, due to the noise. * * * Which is the best detector to use when using radio frequency? On account of the fact that radio frequency allows more energy to be put in the detector circuit than if a detector had been used alone, it is possible to use a crystal detector. A crystal detector is by nature one of the quietest detectors known. It is also distortionless, rectifying the signals clearly. Thus it is seen that if a crystal detector is used with radio frequency, ideal reception will be possible. * * * What tubes should be used when using radio frequency, and why? In the use of radio frequency hard tubes (not gas filled) should be used. This is because they perform the work of amplifiers and are therefore necessarily hard tubes. * * * Can \y2-volt tubes be used jor radio frequency? To a certain extent the popular lj^-volt tubes can be used for radio frequency. That is, not over four stages of radio frequency should be attempted when using the tubes. Due to the nature of their construction they will not stand too much current, and if more than four stages are used there is a great liability of their "breaking down." * * * . What voltage should be applied to the plate of the 1J4- volt tube for radio frequency? In the use of the lj^-volt tube as a radio frequency am- plifier, approximately 45 to 60 volts should be put on the plate. Tubes will operate on as low as 22j£ volts, but not with any fair amount of success. * * * Is one stage of radio frequency amplification practical? Due to the fact that no appreciable increase can be noticed in the strength of the rectified signals when using one stage of radio frequency, outside of a slight clearing of the signals, it is not advisable. Two stages to five should be used to get the benefit that comes of using radio frequency. * * * Can audio frequency transformers be used in radio fre- quency? Audio frequency transformers generally incorporate an iron core. In the general method of making radio frequency transformers, this is not done, due to the inherent quality of iron to dissipate a large amount of the current in high frequency currents in hysteresis. Therefore, audio fre- quency transformers cannot be used. * * * What is a reflex circuit? A reflex circuit is one that uses the same tubes for two different purposes. First it amplifies them at radio fre- quency, then they are rectified and then by means of back coupling them through the transformers they are amplified at audio frequency. This is possible because advantage is taken of the principle of superimposition. Due to the fact that radio frequency is at a much higher frequency than audio, the two can be passed through the same tube and not interfere, much the same as the vision of two people can cross and not interfere with either one seeing the object desired. One Year Lost THE White Bill, safely through the House, is doomed to die in the Senate, says the New York Evening Mail Long neglected, sidetracked, pigeon-holed and evaded, it finally made its way through the lower body of the legislature. It seemed for a time as if it might get on the books. But a jealous, partisan Democrat from Texas, fearing Republi- can control of the air, and a Senate, fearful of giving too much power to a capable man like Secretary Hoover, have combined to act as executioners. These pigeon-minded solons say they tremble at the thought of Hoover as the absolute dictator of radio. Meanwhile the progress of radio in this country is to be set back at least a year, or until such time as public opinion becomes great enough to force the issue, which time will not be long. The demise of the White bill itself isn't the serious part of the matter. It was anything but an ideal bit of legislation. Never- theless, it would have clarified the broadcasting situation consid- erably and would have served a very good purpose until something better could have been devised. All of which should bring every thinker interested in radio to the realization that NOW is the time to get ready a better bill, to force through the two branches, if need be, at the next session. Here is a chance for the real minds in radio to contribute some- thing. If you have some ideas on the subject, or only one, make yourself heard. Some one else may have another. With enough brains working on the subject, a practical bill can be drafted. Send in your ideas and let the bunch talk 'em over in the col- umns which this magazine has set aside for that purpose. If we can, The Mail will find some one to sponsor it and push it You are the one who will have to listen and have to suffer, unless you can think of something better than has been brought out yet Digitized by Google

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RADIO WORLD 11 An Efficient Single Tube Super- Regenerator By Frederick J. Rumford, E.E., R.E. THE improved Armstrong regenerative hook-up bet- ter known as the super-regenerative hook-up, has been experimented with many times since it first made its appearance. One of the very latest is the single tube super set, which has been experimented with by the writer and has been found to be practical and efficient. This single tube hook-up is the result of the extensive experiments . carried on by Mr. Philip Robinson, of the American Radio Relay League, and also has been experimented with by a great number of the advanced radio men. . This set can be constructed at a very slight cost to the experimenter. The writer has blueprinted, construction drawings, and hook-up full size which can be had for a reasonable cost to help offset the cost of tracing and blue- prints. There are very few parts necessary for the actual constructing of this set, and the parts that are really needed can be obtained at a slight cost to the prospective builder. This set will cover successfully a distance of 400 or 500 miles in radius with an average size loop antenna. The writer personally has covered a distance of three hundred miles with a set of this kind. The diagram gives the correct hook-up, both internally and externally, of this remarkably efficient single tube super-regenerative receiver. The following is a list of parts and the respective costs are about as follows: 1 Variometer $5.00 1 1250 turn honeycomb coil, unmounted. . . . 2.50 1 1500 turn honeycomb coil, unmounted 3.00 1 .00025 variable condenser...., 2.50 1 Rheostat 1.00 1 Vacuum tube socket 50 2 .002 mfd. fixed condensers 2.00 8 Binding posts .80 1 Radiotron vacuum tube U. V. 201 6.50 $23.80 When the parts named have been purchased, the builder should go through the usual procedure of mounting the parts upon the panel and the base, the panel being of the desired size, as also the base. He is then ready to proceed with the actual wiring of this set as shown in the illustration on this page. Great care must be taken that the wiring is correct in every respect and it is advisable for the pros- pective builder to study the diagram thoroughly before even attempting the actual wiring. On mounting the various parts upon the base care must be taken that the honeycomb coils are mounted at right angles to, each other. They can be touching, for that mat- ter, but right angled to each other they must be. The variom- eter is used to obtain regeneration, which will give a range of from between 400 and 500 miles in radius by using the usual loop antenna. This also has the advantage of giving directional effects, which in turn reduce interfer- ence and also eliminate a large amount of static. It is not /ferial Ground LIZ50 .002 LlSOOi Schematic diagram of the super-regenerative circuit described in the ac- companying text, The variometer in this circuit la need to obtain regenera- tion, and wiH give a range of from IN to SM meters, dependng of course i what type is employed. advisable to use an outdoor aerial. If the builder of one of these sets wishes, he need not use the usual loop antenna, but can use either a small honeycomb coil or a spider web coil for a loop, grounding the set at the posts marked B. This latter arrangement has not the directional effect that the usual loop antenna has. This set is somewhat critical in operation, but when it is functioning properly there will be a very high note in the head receivers until a phone station carrier wave is picked up. In turn, this high note will give away, bring- ing in the music or voice, whichever the case may be, with the very best of results. The accompanying diagram is self-explanatory and any- one building this set should get satisfaction. Britons Demand More Electricity and Wireless Apparatus ECONOMIC conditions are forcing a broader use of electricity in England, says Commercial Attache W. S. Tower in a report to the Department of Commerce summarizing the British electrical industry in 1922. Only here and there is this trend revealed at present, but there are enough in- dications to show that, apart from the im- petus that will be given by greater activity on the part of the Electricity Commission- ers, the people of England have today an ittitude toward electricity in factory and home that did not exist a few years ago. The domestic market of the United King- dom, therefore, may be expected to show growing strength during the next few years. The electrical export trade during 1922 has not been any more satisfactory than has the domestic, though two large colonial con- tracts which were placed with English man- ufacturers during the past year have helped to some extent. The total value of the electrical goods and apparatus exports in 1922 was hardly more than half of that for the previous year, and this reduction is apparent in all items in- cluded in the table, more particularly in those items relating to electric wires and cables. Telegraph and telephone instru- ments and switchboards constitute the ex- ceptions to this general reduction. The demand for electrical supplies in the home market improved somewhat during the year; a feature was the interest in new wireless apparatus and heating appliances. It must not be forgotten, says Mr. Tower, that the use of electricity and appliances in Great Britain has always been held, back by the activities and influence of the big gas companies who were naturally strongly en- trenched throughout the United Kingdom for many years prior to the establishment of electric companies. The gas companies cooperatively have spent many thousands of pounds sterling annually in advertising ap- pliances to promote the use of gas, while electric current suppliers are usually of the opinion that the business of selling appli- ances should be left entirely to the manu- facturers in order that proper and efficient progress may be made. Digitized by Google

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12 RADIO WORLD Radio Wrinkles By Arthur S. Gordon WHEN the amateur hits on a novel way of doing this, that, and the other thing with his radio ap- paratus, he feels more or less ambitious and tries to get out a patent. According to his way of thinking, he has "discovered" something; while, according to others, he has merely added one more "wrinkle" to the several thou- sand now running around uncopyrighted. As a general rule, wrinkles are too easily explained in a few words for a fellow to write a whole article about them, and so a neat half-dozen are presented in this article, five of which are illustrated. All of them have been tried out, and work as well as they look. A Novel Hook for Handphone* It is safe to say that ninety per cent of the hornless breed of radio amateurs hang their phones on a hook» when they are "signing off" for the night. It is also safe to say that a great many have forgotten to turn off the filament rheo- stat at least once in their radio career, much to the ruina- tion of the A battery. Did you ever think of linking up the craze for hooks with the failing for filament rheostats ? 2 -n n r^^^ . A wrinkle that eve many "A" batteries, as wall u a lot of worry. When you hang up your phone*, the filament current ia automati- cally abut off. That ia. If you are method- ical and banc your phone* on a hook. If not, you wOl have to cultivate the habit and then everything wiU be O. K. Wrinkle No. 1 does just that. It is the design of a head- set hook which automatically turns off the filament current when the phones are on the hook. Figure 1 gives the gen- structional details of this wrinkle, and shows quite plainly that when the phones are lifted from the hook, the spring pulls the brass rod— out of which the hook is made— against the head of a switch point. A connection is made and the A battery current flows as it should. The moment the phones are replaced, however, this connection is broken, and even if the rheostat has been left on. no current will flow through the filament of the tube. The hook proper is made of a piece of lA-vach brass rod, 6}i inches long. It is bent into a right angle shape, as shown, and drilled at the angle to take a 6/32 switch point which acts as the fulcrum. A spring is extended from the lower end of the part which is bent down to the corner of the base upon which the hook is mounted. This base is of wood, the dimensions of which are given. The contact point is embedded in the top of the wireless table, so that only the head of the switch point shows underneath the table. The connections from the A battery to the hook- and from the hook to the binding posts on the panel, are shown in a small insert in the upper right, Figure 1. An Idem for an Indoor Loop There are many kinds of folding or portable loops for household use, designed to give the least amount of trouble with the maximum of pleasure. Who, but the amateur who simply had to have a loop that was practically in- visible, could have thought of winding one in a vertical plane on a door, as shown in Figure 2? The wire used is No. 22 D. C. C. There are ten complete turns in all, each turn spaced one inch from its fellow. Small brads or brass tacks are placed at the corners, and the result is an attrac- tive loo- •' -t is far from being a disfiguration. Fig. 2. Far thoee who do not Hke to have loop antennae hanging all over the room the accompanying; aketch wfll be a welcome euf f ee- uon. Variation of the bop la accomplished by swinging the door. It doea not take up extra apace, and at the earn* time allow* a greater amount of wire to be uaed. A good idea la to tap the wire, and then tuning can be accomplished by using the different tap* of the loop. A really worth-while feature about this loop is that it can be swung for directional effects by merely opening and closing the door, putting a floor stop to hold the door in the most effective position. Roll Your Own Phone Condenser It's a terrible job to make a condenser pack come out right so why not roll the condensers? Figure 3 gives a very good idea of how this is done. A is a cardboard form coated with tinfoil and directly connected to the tinfoil sheet F. The tinfoil sheet D is separated from F by tht waxed-paper dielectric E and is connected with the card- board form B. Two other pieces of waxed paper, C and G, Fig. 3. Illustrate abows the awtfc- od of *VollUi your own" con- denser. Not Butte ae neat aa tht man u f acnee* r o d u c t . p r o d u c but lertti ft much. Care sbooU be taken what making that then Is a genereai margin of waxed paper left are used as shown, and then the whole assembly is wrapped around the two cardboard forms. The result is a neat and inexpensive phone or grid condenser. To get a capacity of .00025 mfds., use two tinfoil sheets, each 5 inches long by 1 fjj inches wide. Cut the waxed paper so that there is a generous margin all around, particularly at the ends. An Every Tarn Contact Switch If you dislike making taps when winding a coil, or if you would rather have a scale and pointer on your panel than a row of switch points, this wrinkle will give you an idea that may be of value. Figure 4 shows what is termed as an every-turn contact switch. Fig. 4. If you dislike to make tape, here Is an idea that win eliminate the troublesome drilling of hole* and locating of ewitchpointa, and at thr una time permit oi single turn variation. The switch arm should preferably be of spring bras* or phosphor bronze, and of sufficient length to reach to the ends o! the coil. The sketch explains itself. The switch knob is of the ordinary type, with its arm replaced by a pointer. Attached to its back-panel end is a long contact arm which describes an arc on the coil when the knob is turned. This arc is scraped bare so that an electrical contact is made with the contact arm. Spring brass will be ideal material for this arm, and the switch should be located so that when the con- tact arm is straight up and down, it is also in the center of the coil. A Hole Plugging Solution for Old Panel* Take a pint of denatured wood-alcohol and break up in (Continued on next page) Digitized by Google

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RADIO WORLD 13 Radio Saves Time and Money for Ship Owners By Arthur G. Shirt NOT so many years ago it was not an uncommon experience for a shipowner to wake up in the morn- ing and find that one of his ships had unexpectedly entered port the previous night. He sometimes became excited, because before the ship could dock there was much to do in the way of arrangements. While these were being made, time was lost as well as money. Now, when a ship approaches port, the Captain sends in the exact time of arrival, so that the home office may pre- pare for the routine of handling the ship in the harbor, getting her to the pier, discharging her passengers and mail, and opening her hatches to discharge her cargo. Before the ship is within sight of the lightship at the entrance to the channel, the Captain is informed by radio whether or not he can dock that day. He knows when he can pay off his crew, and even knows the day when he will again set sail for foreign parts. While the ship is two hundred miles away, her owners know how much coal she will need for the next trip, what repairs are needed, or changes in the official personnel of the vessel. Another feature of radio service while the ship is at sea is the transmission of the daily TR, or "position report." These reports enable the home office to follow the progress of the ship by plotting the noon positions on a special chart. Besides these direct aids there are other ways in which radio saves time for shipowners. One of these is ridding the seas of derelicts — one of the greatest dangers that beset the navigator. The Hydrographic Office issues a monthly Pilot Chart of the great ocean bodies, and, because of the nature of the information of such charts, they are much sought for by navigators. . These Pilot Charts show the position of floating and half-submerged derelicts when and where last seen. This information does not help the navigator a great deal because a derelict will not "stay put." One seen and narrowly escaped, for instance, by Captain Brown, of the freighter Brazen Bell, should have remained to be blown up by the first Coast Guard Cutter that could respond to Captain Brown's warning. But it didn't. Instead, it lead seamen a merry chase, and got under the bows of many vessels and was reported many times. Now, when the radio operator brings the Captain the report that a derelict has been seen in the vicinity, the Old Man is greatly relieved. He carries the warning into the chart room and plots the position of the obstruction on the chart. Then he runs down his course line, ascertains how far away he will pass, computes the direction and speed of the current and the probable drift of the derelict, and then changes course or doesn't, according to his judgment Just as derelicts frequently annoy a ship's navigator, so do chronometers. How fast are they ? How slow are they ? To ease the mind of the navigator in the matter of time, various government stations deem it part of their duties to send out time signals twice daily, and these signals, arriving at the ship by means of radio, are used to place the ever- lasting check on the ship's chronometers. Present day navi- gators have become so attentive to chronometers that they lose their poise when the radio signals are not forthcoming at least once in twenty-four hours. As time "ticks" are rapidly becoming a matter of course, so are the weather reports and special storm warnings. A skipper feels that he has a justifiable grudge against the radio man if the ship runs into a storm without eight or ten hours warning by radio. What a benefit these weather reports are to seamen! They contain information that may help the sailor dodge the storm or prepare for it. Seamen get the position of the storm center, the direction of. the wind, its velocity, the direction in which the storm is moving and its rate of speed. The number of ships which have thus been saved from the consequences of a storm would mount up into thousands. Can You Carry a Message to Garcia ? In most every city (outside of New York) are manufac- turers of radio goods who are really anxious to get the patronage of our 70,000 readers. These manufacturers would sign an advertising contract quick if they only knew what a wonderful advertising medium Radio World really is, but we have all been so busy here in New York we have not had the time to go out and personally solicit them. Will you undertake to carry one message a day for us? We will supply the mes- sage, tell you whom to carry it to, and, if you put over the message, pay you a handsome commission, and all without interfering with your other work. If you have the ambi- tion to earn some substantial extra money, write F. S. Clark, Manager, Radio World, 1493 Broadway, N. Y. (Continued from preceding page) it an old phonograph-record, so that all the pieces of the record are covered by the alcohol. Let the mixture stand for a day and a half. At the end of that time, you will find that the formerly hard record has dissolved into a* workable paste or black plaster. With this putty like sub- stance' fill up the holes in your discarded panel, and use it again on that new set you may be making. When the holes are filled up, and the hard rubber paste is dry and hard, give the face of the panel a coating of the same thinned- down solution. Then polish it with a fine piece of sand paper, or with pumice stone, and you will have the neatest dull-finished panel you ever want to see. In using a one-step amplifier with dry cell tubes, it has been found more economical to use two dry cells — that is to say, one separate dry cell to each tube — rather than to Fl#. S. A hookup far two WD-U tubas, which la mm* eco- nomical hi the dm of fill—lit currant be- cause of the fact that each tube has a sep- arate dry call anp- ptyinc the filament. connect the two filaments to the same dry cell. A hook-up showing how this is done is given in Figure 5. The essential qualities of a regenerative hook-up are in no way changed, with the exception that the extra filament battery is inserted for lighting the filament of the amplifying tube. This last idea, although it has to do with a hook-up, is as much a radio wrinkle as those ideas which concern the construc- tional features of a radio outfit. Digitized by Google

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14 RADIO WORLD Radio and the Woman By Crystal D. Tector A FRIEND of mine recently returned from Sunny France, and outside of bringing various beautiful gowns and other personal things, she brought me the dearest little French tube you ever saw. I might mention, by the way, that until she sailed for France she had never taken the least interest in radio, aside from coming in to listen to the style and fashion talks every little while. It was quite evident that the operator on the ship must have been a very hand- tome chap, from the way in which she talked about the "ship's radio." * * * THE fact that radio is an important science in our daily life was illustrated the other day in the following way: Friend Hus- band (who is a lawyer) had a case in which a young man had absconded with a sum of money and for two months had not been located. As a final resort the firm had bis description broadcast through one of the larger stations. Result: He was found in a nearby town, living under an assumed name and working nights to escape detection. One of the men he was working with had heard the broadcast and advised the police of the town that the man wanted could be obtained at a certain address. Well, that is just another step in putting the fear of God and the dread of police in the hearts of evildoers, is my way of thinking. * * * POOR F. H. told me last night that he is going away for a few days on a business trip. When I started to feel sorry for him in the conventional wifely manner because he would miss his daily radio ration, he smiled indulgently at me and said: "Have you lost your respect for my resourcefulness? Why, I've already made arrangements for my railroad passage on a line which has in- stalled radio sets for the convenience of its passengers and I've also wired for reservations at a hotel where radio is part of the serv- ice 1" After all, it really is difficult to discourage a real fan, even if he is a husband and is more or less accustomed to being sup- EVERY once in a while some of my friends get a "wild idea," and appeal to me to help them carry it out. The latest "wildness" was suggested to me by a little lady who had recently been married to a fine boy we all know. The "idea" was that she wanted to give him a present, preferably a radio set She had seen pictures in Radio World of a set concealed in a tie-pin and wanted to know if F. H. wouldn't build her one to give him. She said that she had gone down to Tiffany's and bought the "dearest little pin you ever saw, and I want to leave it here for you to fix up for me. You know his birthday is next Wednesday and I'd love to give it to him then." Oh I Oh I Evidently radio sets in tie-pins must be the easiest thing in the world to make, outside of writing the Lord's prayer on the head of a pin. GIRLS, I have a new scheme for making "pin money." The idea is perfectly legitimate, and I can make enough to treat myself to a matinee and tea at least once a week. I simply get my friends to subscribe to the Radio World. The idea was suggested to me by a visit to "Ye Editor" the latter part of last week. I think that it is a very fine idea, and it doesn't take much time to sell anyone a subscription to a good radio maga- zine these days, especially when the magazine is a weekly, and is therefore weeks and weeks ahead of the other magazines in its news and pictures. Write in. * * * FOR every wrong way there is an easier right way" was demonstrated to me very forcibly last Wednesday. The ocasion that causes me to wax philosophical was this: I had tried and tried for days and days to get "hubby dear" (you girls will understand what I mean), to buy me another pair of Radio Boots, but without success. Well, I finally became tired of telling him to stop in and bring a pair home, so that memorable morning I arose from my "downy" with a very apparent "grouch." During the course of breakfast I "took it out on the boss," and when he very meekly returned at night, he brought me a pair of boots and, also, a box of candy. Nothing like doing things "in the right way." * * * A GREAT many of my friends tell me that they have no trouble in operating their sets, but would like to try a few experiments once in a while. They set those cute little diagrams of various DX hook-ups in Radio World, but always complain that they can not possibly hope to understand the meanings of all the little hooks and dashes and wires. Take a page from the book of your younger days, ladies, and think how difficult it was for you to understand the first dress pattern you used for the first (and sometimes, only) frock you made. A diagram of a hook-up is no more intricate or harder to solve than a dress pattern, so don't be discouraged. And remember — you don't have to wear the set you build yourself I * * * SOME people are certainly persistent. The other evening a few of my friends gathered in my house to have the regular Thurs- day night "Radio and Gabfest." During the evening, a little old lady hapened to mention the word wireless. "By the way," she remarked, " they don't use wireless much now since radio has come in, do they?" "Why, that is just two names for the same thing," I replied. Well, for the rest of an hour and a quarter, the argument waxed hot and heavy, and in the end we had to resort to the almost sagacious advice of F. H., who settled the matter by telling the opposing parties that wireless and radio were the same thing, and that wireless did not mean code alone and that radio did not mean broadcasting and telephone. Obi some people are so stupid — they simply will not listen or believe. Radiograms A GERMAN electrician and radio expert recently made a study of atmospherics, commonly called static. Amongother things he found out that with an outside antenna it took .000000005 ampere to cause a disturbance in a receiving set. * • * A SPECIAL program was arranged at the Cuban radiophone station PWX when Lemuel Bolles, National Adjutant of the Amercan Legion, addressed the veterans of the World War. The program started at 9 P. M., Eastern standard time, and Mr. Bolles addressed the vast unseen audience at 10:30. After the address, the American Military Band of Havana gave an interesting program of American military music of pre-war days. * * * THE first authentic attempt to talk from coast to coast by means of radio telephony was only partly successful, due to outside interference. The test was made between the two stations WOR (L. Bamberger, Newark, N. J.) and KHJ ("Times-Mirror" of Los Angeles, Calif.). The experiment was made between 2 and 4 o'clock Sunday morning, Feb. 18. Dr. Lee de Forest was operating at the Newark end, and made an address, part of which was suc- cessfully reported at the Los Angeles station. The Los Angeles station then followed him up with its regular program, part of which were very plainly heard at the Newark station. The entire programs would have been received had it not been for the inter- ference, chiefly from ships at sea, and from numerous CW stations in between, which caused enough interference to make signals entirely inaudible at times. ANEW secret coding device was recently demonstrated before the officials of the navy during its recent manoeuvres. By means of this device, over twelve million codes are possible, each one controlled by a secret key-wheel which is the basis of the in- vention. The device resembles a typewriter, but instead of the regular type faces, there are numerous dials that are revolved. At present the entire device is being kept a secret, but in a statement given out it is said that it will make the decoding of messages im- possible without the use of a duplicate set of key-wheels at the receiving station. This device will do away with the code books now used, and which are in constant danger of being stolen. It will do no good for anyone to steal the code wheels, as the code is used only once, it being impossible to get the same combination a second time' without going through the twelve million combinations. THE fact that radio is important to the churches was recently shown vividly in an address made by the Rev. Dr. E. J. Van Etten, of Calvary Protestant Episcopal Church, Pittsburgh. Dr. Van Etten said in part: "Radio broadcasting of church services will prove something of a disintegrating force of the church organ- izations themselves. Only the fittest preachers will survive, and struggling churches will more or less be backed to the wall." This, explained Dr. Van Etten, was because of the fact that the larger churches that broadcast sermons proved so much more of a magnet to a larger number of people that it was actually drawing among the congregations of the smaller churches, if not taking them away. "Many people," he continued, "are taking the following view of the entire matter : "Why should I go to hear so-and-so when I can sit at home and listen to the entire services of any one of a half-dozen of the larger and more important churches scattered throughout the eastern part of the country?" Digitized by Google

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RADIO WORLD IS Sends Stock Reports Over Radiophone THE Huth-Funken Telephone Company, of Berlin, is sending stock reports to its clients by means of radio instead of through the ticker, as in this country. Sub- scribers wishing the stock service have a radio receiving outfit such as is pictured in the accompanying photograph over which they receive the reports of the various bull and bear activities on the Berlin Exchange. This was made possible through an ar- rangement with the Berlin Stock Exchange, and has proved a success. The only drawback is that as radio broad- casting is open to every one, any one own- ing a receiving set can get the reports. But this is not a serious drawback as any per- son can look at a ticker, the only difference being that where you probably had to go around the corner to reach a ticker you now have only to pick up your bead phones and listen. The idea has 'proved such a success in Berlin that there are several other countries seriously thinking of adapting it to their stock exchanges. The idea is a time-saver in more ways than one inasmuch as with die present system wires have to be installed whenever a new ticker is to be installed, and also the appa- ratus used in the present system is so com- plicated that it takes a staff of expert mechanics to keep it in constant repair. With the new system, of course, this is rendered unnecessary. By Otto M. Falhaber (C. Gilliams Service) Interior of the Huth-Funkan Telephone Co., which sends Berlin Stock Reports over radiophone. The girl at the left of the photograph la transmitting the report*, which are picked up by the various offices by means of a receiver Identical to the one directly over the head of the man seated at the desk. The receiver, as will be noted, is of the type that needs no tuning*, being switched on by simply raising* the receivers off the hook. Radio Service for Army Chaplains Suzuki "Breaks CHIEF of Army Chaplains John T. Axton announces, with great pride, the broad- casting of Army religious services from four Army radio stations. This new public re- ligious service, which was undertaken with die authority of the Secretary of War and the cooperation of the Signal Corps, was first broadcast from Army posts at Forts Crockett and Sam Houston, Texas, and fol- lowed at Camp Lewis, Wash., and Fort Leavenworth, Kansas, with marked success. At the two Texan posts radio sermons and services were both sent and received, Indi- cating that broadcasting is possible in order to cover a large territory where Sunday services are not available. It is said that some radio-fans in districts far from community centers heard services on the Sabbath for the first time in months. Instead of being confined to small assem- blies audiences of unlimited size are assured Army chaplains for the first time. The transmission of sacred music by voices and bands is also handled as part of Sunday programs. At small posts where no chap- lains are stationed receiving sets rigged by Signal Corps men, now pick up the divine services broadcasted from distant stations. Capt. Robert H. Smith, who sent the first cablegram across the Atlantic on the second cable, laid by Cyrus W. Field in 1866, died recently in his eighty-third year. Rothafel Returns from England S. L. Rothafel, of the Capitol Theatre, New York City, is shown here in his stateroom on the Berengaria during bii recent trip to England The radio set enabled him, during- the voyage to hear the Capitol or- chestra through the Am. Tel. A TeL Co.'s station, WEAF. Photo by Bradley & Merrill Through" HAVE been reading Radio World right along and I would say that all the DX Owls making record with the conven- tional outside aerial but how about mine? I am getting all the stations within 1,000 miles from here, but I heard KFI, Los Angeles, at 2 A. M. last Sunday Q. S. A, and listen, my outfit is of 3 stages of radio frequency amplification with TJV 1714s, W. E. 216a tubes and UV200, Baldwin C tones with 5 turns of 4 foot loop in steel Bldg. KFI is more than 2,000 miles air line. Do I get any credit for my set? Do you con- sider my set just the same as the one with outside aerial? My hook up is a regular Radio Corporation's, but used with best parts that I can find on market Yours truly, 73's Y. T. SUZUKI, (Japanese Radio Bug) 420 Post Bldg. Battle Creek, Mich. Digitized by Google

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RADIO WORLD News Pictures from Radio Worl< Captions by Robert (C. Keystone Views) Frederick Charles Fleche, a London taxi-driver, is an ardent radio fan. This fa denoted the fact that he has even installed a set on the cab he uses to "pick-up" fares. His is in ureal demand, because it 1* the only one In "dear oT Lunnoa" having a radio set on it. (C. Gilliama Service) One of the huge steel towers of the Radio Central Wire- less Station at Rocky Point, Long Island, N. Y, There are to be seventy-two of these monstrous towers, arranged in the form of the spokes of a wheel, the periphery of which is to be three miles In diameter. Each of the spokes is to have six of these towers, and there are to be twelve spokes. The towers are 410 feet high and weigh 180 tons each. ki. tiauei and Herbert) Two new water-cooled vacuum tubes used In place of the high frequency alternators for trans- oceanic radio work. Up to the present rime it has been the custom to use large alternators for providing the high fre- quency currents for trans-oceanic work, but recent experiments with 20 lew water-cooled tubes such as shown in the picture will in the future make the alternators unnecessary.

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RADIO WORLD \7 Over for fC. Keystone Views) Cabin of tba H. M. S. Impregnable that has been re-erected In Auto- voyer'e Wireless Store in Victoria Street, London, as a demonstration room. It la complete in every de- tail, even tbe brass fit thus and lamps of the original ship bein* used. It la one of the novelties of tbe largest radio store In

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18 RADIO WORLD / have a regenerative set, but when listen- ing to distance stations I am bothered with a whistle and squeal and cannot hear them. My set is shielded. How can I remedy the troublef—Nick Tirone, 261 Seat on Avenue, Roselle Park, N. J. Decrease the B battery current, or better yet, use a potentiometer. Don't burn ybur tubes too high. Burn them just high enough get the oscillations started. If burnt too high, they force oscillations. * * * 1. Enclosed please find diagram of my set. It worked fine until a couple of days ago, then it refused to work. My connections are all tight. What can be the trouble? When I disconnect the variable condenser "in the aerial circuit and hook my aerial di- rectly to the set, I get music faintly. 2. Why are some tubes (.detectors) louder than othersf—Karl Day, Dwight, Kansas. 1. Your diagram is correct We suggest that you put a new B battery in the circuit and go over your connections very carefully. If they are soldered, look at them very carefully, as the flux might cause corrosion, which will seriously damage the sensitivity of the circuit Your connections on your condenser are evidently making bad contact Also, examine the lugs of your tubes, and sandpaper them lightly to remove any dirt or corrosion that may have accumulated. Keep all the contacts clean. 2. This is due to the fact that some tubes are exhausted to a greater extent than others. * * * What is the tube U. V. 201 A, and where is it possible to get itf—R. Prentiss, c/o Chas. Parker, High Street, Meriden, Conn. This is a new tube recently brought out by the Radio Corporation, and does not con- sume as much current as the regular U. V. It consumes one-sixth of the regular cur- rent. It can be had at any of the larger radio supply stores, or the nearest branch office of die Radio Corp., or Westinghouse Electric Co. * * * I have constructed the WD-ll set de- scribed in your Jan. 20. issue, but cannot get it to work properly. What can I dor— Chas. G. Rose, Lorain, Ohio. Switch the B battery leads and put on more plate voltage. See that the set is wired correctly. Use a variable grid leak. Test out your circuits by means of a battery and buzzer. * * * How can I make a rectifier for charging a 6-volt 40-ampere hour battery from a 110- volt 60-cycle alternating current line.—L. A. Remfry, Jackson, Miss. Take two plates of aluminum about 6x3 inches and two like plates of lead. Fasten an aluminum and a lead plate on a block of wood about 1-inch square, and long enough to project one inch beyond each end. When both of these units are made up, take 2 mason jars or any receptacle that will hold the plates and fill them full of a solution of borax and water. Allow this solution to stand for about an hour, when the borax that did not dissolve will precipitate and lay on the bottom. Poul off the solution, and wash the rest of the borax out of the jar. Replace the solution and put the two alum- inum and lead elements in the two jars. This will give you two rectifiers each containing a lead and an aluminum plate immersed in a solution of borax. The wooden piece that projects will serve to prevent the element from falling into the jar. Fasten a wire onto each, and hook-up as follows: The aluminum plate of one of the jars goes to the positive pole of the battery, and the aluminum plate of the other goes to the line. Then connect the lead plate of the first recti- fier to the series bank of lamps (4 60- watt lamps in series parallel will do) and the aluminum plate of the other jar to the other or open end of the line. This will allow you to rectify both sides of the current and when your battery is bubbling or tested by a hydrometer the correct charge can be found. It will generally take about 10 or IS hours to charge a battery. * * * Will the set described by John Kent in the Jan. 27 issue tune out local stations ? If not give me a hook-up of a two tube (WD-ll) set that will accomplish this.— Robert Jacobs, 112 W. Irvinton Place, Denver, Colo. This set is extremely sharp in tuning, and will tune out local stations. Of course, it is impossible to tune out stations if you are very really close to them. If they are at some distance, it is possible with this hook-up. i * * * My antenna is between the house and bam, and is strung up on two poles. Will it be necessary to ground the poles, or is grounding the antenna when not in use" sufficient? The aerial is ISO feet long.— Leo Clark, Seward, Nebraska. It will not be necessary to ground the poles, provided they do not project too high above the roof. If they are over fifteen or twenty feet above the highest part of the roof, it is better if they were grounded ; that is, provided that they are metal. If they are wooden, you cannot ground them, as you cannot ground any wooden object, it being an insulator even if a poor one. * * * Publish a hook-up for a U. V. 200, one vario coupler, two variometers, condensers, rheostats, etc. With my present regenerative hook-up I am enabled to get only nearby stations. Will this improve my reception?— J. Walton Holmes, 521 Kew Gardens Road, Richmond Hiu, N. Y. We refer you to our issue of Radio World dated Oct. 14. On page 4 you will find a hook-up similar to the one you re- quest with full constructional details of the variometers and variocoupler construction, by G. W. May. » * * 1. Kindly furnish me with a hook-up using a WD-ll, 2 honeycomb coils, and con- densers. 2. Also a hook-up with one honeycomb coil tube and condensers. 3. Can a WD-ll tube be used with the Flewellmg circuit, or is a six-volt tube necessary? 4. Are honeycomb coils better than vario- couplers?—D. V. Keedwell, Independence, Missouri. 1. We refer you to the hook-up by Ortherus Gordon, published in our issue of Jan. 20. This article includes all the par- ticulars for panel, and also for making the coils. 2. See the article by G. W. May in Radio World of Feb. 17, on page 11 3. The WD-ll can be used with this hook-up, but only 60 volts should be put on the plate, as if more than that is used there is a liability of the tube breaking down. 4. Due to the fact that a greater range of wave length is possible with the honey- comb coils, they are sometimes preferred to the coupler, which is only useful through- out a comparatively small range. * * * 1. Does the De Forest D7 Reflex set use a variocoupler, or is it tuned by a con- denser? 2. If a tuner is used, is a variable con- denser used in the open circuit? 3. Can you give me the capacities of the condensers? 4. How can I construct a 50,000-ohm re- sistance unit? — 5. /. Gordon, 458 Tompkins Street, New York Ctiy. 1. This set is constructed in such a man- ner that either antenna and ground, or loop can be used. This is accomplished by using a double circuit plug. When the loop is plugged in, it automatically cuts the coupler out. Across the secondary of the vario- coupler there is a condenser. When the loop is inserted the set is tuned by means of the condenser. 2. There is also a condenser in the open circuit. This is cut out when the loop is inserted. 3. The capacities are .001 in the primary, and .0005 in the secondary. 4. It is cheaper to buy these than to make them, as winding high resistance wire on a suitable core entails a lot of work They can be obtained in any radio or elec- trical shop. * * * What is the diameter of the pasteboard tubes used for the variocoupler in the arti- cle by Ortherus Gordon in the Jan. 20th issue of Radio World/— F. N. Cash, Nor- wich, Conn. The diameter of these coils should be 2 inches. * * * 1 1. How can I construct the coils men- tioned in your article by Ortherus Gordon in Radio World, Jan. 20? 2. Should the coils be in opposition, or must both the windings run in the same position? 3. Does it matter which coil goes to the plate?— Richard Blair, 17 CKfton Park, Pittsburgh, Pa. 1. These coils and their construction are fully explained in the text under the head- ing "The Variocoupler." 2. The coils should run in the same posi- tion; that is, the windings should follow each other. 3. The top coil should go to the plate, and the outside end of the winding is die one that connects with the phones. The in- side of the winding goes^to the plate itself. Please publish a reflex amplifier circuit using two tubes.— Honor e Girouard, BScui., Drummondville, P. Q. We refer you to the article appearing in this issue, by W. S. Thompson, E.E. Can you give me a hook-up using two tubes and a crystal with two stages audio and two of radio?— R. B. Eaton, 20 Maple Baine Avenue, Toronto, Ont., Can. We refer you to the hok-up published in this issue, under the heading "Mr'Mple Tube Reflex Circuits," by W. S. Th. . ^on, E.F~ The first article of this series' was published in our issue of Feb. 24, and con- tains some very good explanations of reflex circuits, as well as several very interesting diagrams. Radio WorU, 52 i HM m ymtr, $IM i months, $159 thrtw months, World, 1493 Broadwstf N. T. C Digitized by Google

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RADIO WORLD Latest Radio Patents New Method of Signal Reception No. 1, : Patented Jan. 23, 1*23. Patentee: Bradbury, Schenectady, N, Y. THE present invention of Mr. Bradbury relates to a radio receiving system, par- ticularly to systems for receiving continu- ous wave signals. In some cases where it is desired to re- ceive continuous wave signals by some method, such for example as the heterodyne method, for rendering such signals audible, Diagram of Mr. Burke Bradbury's Invention, miking it possible to receive continuous wave signals without the use of the regular heterodyne method generally employed. As will be seen, a double coupled circuit is used with a valve de- tector. it will be found difficult to tune a receiving system sharply enough to eliminate the effects in the receiver of stations of neigh- boring wave length which are either of higher power or located much nearer a re- ceiving station than the one from which signals are to be received. The object of the invention is to over- come such difficulties as the one .mentioned and to provide a means for eliminating the effect in the receiver of interfering signals. The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation will best be understood by reference to the fol- lowing description taken in connection with the accompanying drawing in which is illus- trated diagrammatically one way in which the invention may be carried into effect. There is indicated in the drawing an an- tenna 1 with the usual tuning inductance 2 and a coupling transformer 3 by means of which the received signals are impressed upon the grid circuit of a detector 4 of the electron discharge type. The plate and grid circuits of the detector are coupled together at 5 in order that the detector may generate local oscillations of a frequency slightly dif- ferent from that of the signals which are to be received. Coupled to the plate circuit of the detector 4 by means of the trans- former 6 is a separate circuit in which are provided two frequency traps. One of these which comprises the capacity 7 and parallel inductance 8 is tuned for the frequency of the signals to be received, the usual tele- phone receiver 9, or any other desired form of indicator, being connected in parallel to this trap. The second trap made up of the condenser 10 and parallel inductance 11 is tuned to the frequency of the interfering signals which it is desired to suppress. This second trap offers a high impedence in the circuit to the flow of currents of the inter- fering frequency and thereby prevents such currents from affecting the telephone re- ceivers 9. In case the second frequency trap does not completely prevent the interfering signals from affecting the telephone receiv- ers a coupling 12 may be provided between the two frequency traps for the purpose of impressing upon the first frequency trap a current of the proper phase and intensity to neutralize any current of the undesired fre- quency which may flow in the first trap. Duplex Wave Transmitter No. M4USS: Patented Fab. S, 1*23. Patentee! Lloyd Espenschield, Hoffia, L. 1, N. Y. THE invention of Mr. Espenschield's re- lates to wireless signaling systems, and more particularly to a wireless duplex sig- naling system. The object of the invention is to provide a system for the simultaneous transmission and reception of signals, and in particular to provide means for duplex communication between two stations. For successful duplex operation it is necessary that the receiving arrangement be effectively protected from interference by the trans- mitting arrangements associated therewith; that is protected from what is known as "side t' " It is well known that in wire- less telei;,. *ph and telephone systems the magnitude of the transmission current is enormously greater than that excited in the antenna by die received waves, the relative magnitude of the former with respect to the latter being of the order of one million to one. This enormous ratio renders- inap- plicable to wireless systems the means of transmission interference elimination which are successfully employed in ordinary wire telegraph and telephone systems. The wire- less system is, however, differentiated in two important respects from the ordinary wire system; first, sigr. Is are transmitted on high frequency can er waves of definite frequencies, this fact permitting of the em- ployment of different frequencies for trans- mission and reception, and secondly resonant tuned circuits may be employed, thus ren- Mr. Lloyd Espenschield's method of transmitting. This new system will permit duplex slon. The figures show two different accomplishing this, as explained in panying text, dering the receiving system selective with respect to the waves it is desired to receive. In the invention I provide successful duplex operation by employing carrier waves of different frequency for transmission and reception, by providing separate antennae for transmitting and receiving, the said an- tennae being located a considerable distance from each other, and by neutralizing the in- ductive action of the transmitting system proper on the receiving system by means of balancing circuits. New Crystal Detector No. l,44UMi Patented Jan. t, 1*23. Patentees Emmet P. Lindner, IndWnapoUs, lad. THIS invention of Mr. Lindner's relates to crystal detectors as used in wireless receiving apparatus, and an object of the invention is to provide a carborundum detector which is constructed to permit movement in any necessary direction, mak- ing it possible to engage any sensitive spot on the mineral crystal with centralogical pressure of the contact point of the detector, thus making the detector very sensitive, as — «7 A new crystal detector invented by Emmet P. which allows flexibility in finding the st sensitive spot, aa well as making the ad- lermanent when once found. It is for use with a carborundum detector or one requiring a very hard and steady pressure. any spot on the surface of the mineral crystal can be met at any required pressure; also to provide a detector as specified, which is constructed to securely maintain the movable contact in any adjusted position against vibration occasioned during the use of the apparatus, and which will also per- mit the contact to be maintained in proper engagement with a sensitive piece of mineral crystal without the contact slipping. Another object of the invention is to provide a wave detector which comprises a carrying rod, on which it is mounted, for longitudinal movement ; a carrying block for the contact spring, the contact point of which is sharpened to permit sensitive and accurate engagement between the contact point of the spring and a carborundum or mineral crystal, and also to provide a sup- porting structure for the carrying rod, which comprises a sphere or ball on the end of the rod, engageable in a suitable socket, the frictional engagement of the ball with the socket being regulated by a spring plate which grips the surface of the ball opposite the socket, and the tension of which is adjusted by adjustable thumb nuts. A further object of the invention is to provide a holder for the mineral crystal, which is rockably supported relative to the detector, and comprises a suitable cup in which a spring clip is mounted for yieldably engaging the mineral crystal and maintain- ing it in proper position. 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20 RADIO WORLD New Records of The DX Nite Owls Well Repaid by the Enjoyment From Charles A. Smith, RoseUe, N. J. After reading your column, "Latest from the DX Nite Owls," I am not ashamed to submit this list of distant stations. These have all been tuned in on detector only. My set is a single circuit regenerative two- step audio amplification, designed by the Consolidated Radio Call Book Co., and built by the writer from plans furnished by them. I feel that I am well repaid by the enjoy- ment gotten for the loss of time and sleep. I don't know what kind of an owl "DX" is, but I must be some sort of a "bird" to stay up half the night The stations alluded to are as follows: Distant Stations, 360 Meters— WGY, Schenectady, N. Y., General Electric Co., ISO M. ; WGI, Med ford Hills, Mass., Amer- ican Radio and Research Corp., 250 M. ; WFI, Philadelphia, Pa., Strawbridge & Clothier, 90 M.; WHK, Cleveland, 0., West- inghouse, 410 M. ; WSY, Birmingham, Ala., Alabama Power Co., 900 M.; WLW, Cin- cinnati, O., Crosley Mfg. Co., 560 M.; WLK, Indianapolis, Ind., Hamilton Mfg. Co., 725 M. ; WWT, Buffalo, N. Y., McCarthy Bros. & Ford, 300 M. ; WRW, Tarrytown, N. Y., Tarrytown Radio Laboratory, 35 M. ; WBT, Charlotte, N. C, Southern Radio Corp., 500 M.; WMAF, South Dartmouth, Mass., Round Hills Radio Corp., 225 M.; WDAP, Chicago. 111., Midwest Radio Central, 525 M.; KDKA, Pittsburgh, Pa., Westinghouse Mfg. Co., 325 M.; WHAM, Rochester, N. Y., Rochester University, 300 M.; WLAG, Minneapolis, Minn., Cutting & Wton Radio Co., 1,050 M.; WDAJ, College Park, Ga., Atlanta & West Point R. R., 800 M. ; KOP, Detroit, Mich, Detroit Police De- partment, 325 M.; WFAJ, Asheville, N. C, High Grade Wireless Co., 675 M.; WEAN, Providence, R. I., Shepard Stores, 175 M. ; WHN, Ridgewod, L. I., Ridgewood Times, 20 M.; WHAS, Louisville, Ky., Courier- Journal, 675 M.; WOAX, Trenton, N. J., Frank J. Wolff, 40 M.; CFCA, Toronto, Can., Star Pub. & Printing Co., 350 M. Local Stations, 360 Meters— WJZ, New- ark, N. J., Westinghouse, 7 M.; WBS, New- ark, N. J., D. W. Mays, Inc., 7 M. ; WDT, Tompkinsville, N. Y., Ship Owners' Radio Service, 10 M.; WNO, Jersey City, N. J, Wireless Telephone Co., 12 M.; WVP, New York, N. Y., Signal Corp., 15 M.; WAAM, Newark, N. J., I. R. Nelson & Co., 7 M.; WBAN, Paterson, N. J., Wireless Phone Corp,, 20 M.; WWZ, New York, N. Y„ John Wanamaker, 15 M. ; WE AM, N. Plain- field, N. J., Borough of N. Plainfield, 10 M.; WD AM, New York, N. Y., Western Elec- tric Co., 15 M. Distant Stations, 400 Meters— WBZ, Springfield, Mass., Westinghouse, 200 M. ; WSB, Atlanta, Ga., Atlanta Journal, 800 M. : WIP, Philadelphia, Pa., Gimbel Bros., 90 M.; KSD, St Louis, Mo., Post-Dispatch, 950 M.; WHB, Kansas City, Mo., Sweeny School, 1,200 M.; WOC, Davenport, Iowa, Palmer School, 950 M.; WWJ, Detroit Mich., Detroit News, 325 M. ; WNAC, Bos- ton, Mass., Shepard Stores, 225 M. ; WHAZ, Troy, N. Y., Rensselaer Institute, 175 M.; WGM., Atlanta, Ga., Atlanta Constitution, 800 M.; WBAP, Fort Worth, Texas, The Star Democrat 1,500 M.; KYW, Chicago, 111., Westinghouse, 525 M. Local Stations— WOR, Newark, N. J, L. Bamberger & Co., 8 miles; WCAF, New York, N. Y., Western Electric Co., 15 M.; WBAY, New York, N. Y., American Tel. & Tel. Co., 15 M. Your magazine is much enjoyed by me and my friends, and it carries "the real dope." THE Editor of RADIO WORLD will be pleased to receive sketches of hook-ups drawn carefully in black ink or heavy pencil from the "DX Nite Owls" whs send in records with a view to publishing; them. Send hook-ups of your sets, provided they contain something unusual Send, also, the names of the various makes of apparatus you are using. Writs on one aids of the paper only. The letters and hook-ups will bo pub- lished In the earliest possible numbers of RADIO WORLD. A Five-Months Fan From Quentin Weaver, Saratoga, Texas Enclosed you will find a hook-up which I believe gives remarkable results. As I have been a fan only five months, I think that the following is a fair record. To date I have received 76 stations in 26 different States and Havana, Cuba. The farthest sta- tion being KDZT at Seattle, Washington, • at the distance of 2,100 miles. Here is a partial list: WLW, WEAO, WHK, WWJ, KLZ, KWH, KHJ, WHA, WLB, WAAM, WPJ, KFAE, WFAF, WBZ, KZN, and PWX. My aerial is a single wire 150 feet long and 50 feet high. The primary condenser CI should be treated in both series and parallel for best results. The coils are honeycomb coils and the turns are marked on the diagram. On the diagram I show 22J4 volts on the B battery of the first tube, but I find that 45 volts work the best. The potentiometer is 500 ohms, but any potentiometer of 500 ohms or over can be used. i I noticed in a recent Radio World a story about Radio Golf. I have a fairly good score myself. Here it is : WEV, Houston, Texas, 70 miles; WMAM, Beaumont Texas, 40 miles; WEAF, Houston, Texas, 70 miles; WDAO, Dallas, Texas, 260 miles; WOS, Jefferson City, Mo., 605 miles; WOC, Davenport, Iowa, 865 miles; WBAP, Fort Worth, Texas, 278 miles; WOAI, San An- tonio, Texas, 263 miles; WPA, Fort Worth, Texas, 278 miles; WGM, Atlanta, Ga., 679 miles ; WDAF, Kansas City, Mo., 635 miles ; WHB, Kansas City Mo., 635 miles; WRW, Tarrytown, N. Y., 1,515 miles; WHAS, Louisville, Ky., 755 miles; KSD, St. Louis, Mo., 637 miles; WDAJ, College Park, Ga., 639 miles; WFAA, Dallas, Texas, 260 miles: WLB, Minneapolis, Minn., 1,065 miles; PWX, Havana, Cuba, 901 miles; WKAL, Orange, Texas, 67 miles; WSB, Atlanta, a., 679 miles; WDAP, Chicago, 111., 933 miles. Total: 12,129 miles in three hours and thirty minutes. Mileage per hour, 3,465 miles. I believe this nears the record of Mr. Anthony, of Needham, Mass. Joins Our "Nite Owls" From Willi* Nye, 11* East Sonoma Avenue, Stockton, California WOULD like to join your "DX Nite Owls" Society. I will give my qual- ifications. I use an inductance with 8 taps, in inductive relation to a variometer, a 23 plate condenser, one vernier condenser, grid leak (variable), grid condenser, one tele- phone jack, vernier rheostat tube, variable "B" battery, and "A" battery and Federal phones. I have got the following DX sta- tions beside many local stations within one hundred miles radius of my home. My aerial is 20 ft high, 80 ft long; 1 wire KHJ, Los Angeles; KZN, Salt Lake City; KGG, Portland; KFC, Seattle, Washington; CKCK, Regina, Saskatchewan, Canada; KLZ, Denver, Colorado; KFI, Los Angeles, Cal.; KFBC, San Diego, Cat; CFCN, Calgary, Canada; KFAF, Denver, Colorado; WBAP, Ft. Worth, Texas; KWH, Los Angeles, Cal.; KDYL, Salt Lake City; KFBD, Hanford, Cal.; KNI, Eureka, CaL; KFAY, Medford, Oregon; KGW, Portland, Oregon; 6XAD, Catalina Island; KFAE Pullman Washington; CFCB, Vancouver, British Columbia, Canada. Locals within 120 miles: KUO, S. F_ Cal.; KWG, Stockton, Cal.; KFBK, Sacra- mento, Cal.; KJQ, Stockton, Cal.; KXD Modesto, Cal.; KFGH, Palo Alto, Cal. KFDB, S. F., Cal.; KVQ, Sacramento, CaL KZY, S. F. Cal.; KDN, S. F. Cal.; KJji Sunnyvale, Cal.: AGI, Presidio, Cal. KRE, Berkeley, Cal.; KZM, Oakland, Cal. KLX, Oakland, Cal.; 6XJ, S. F. CaL KLS, Oakland, CaL; KQW, San Jose, CaL 6AJD, Stockton, Cal. ; KYY, San Francisco, Ca. I use only one tube. Hookup with which Mr. Weaver (an letter on this page) has done soma remarkable work. Take note of the fact that he uses separate batteries for his amplifier. This is a good Idea, if the bull dor space to i batteries. It allows better re- ception through the amplifying circuits. This is because there is less chance of the anipHIWi oscillating, due to enforced os- cillations through the battery circuit! from the detector cir- cuit. Without Amplification From Kenneth I. Scoutan, Los Angelas, ( HAVE a record which I consider un- usual for a crystal set without am- plification. Have listened in to concerts from KPO and KUO, San Francisco, and KZN and KDPT of Salt Lake City, com- ing in loud and clear. Local stations' can be heard all over the room wdth phones hanging on the walL My aerial is 4-wires 60 feet, 30 feet high. The set is entirely home-made, with the exception of the phones. * * * Another 1-Tube Froas Fred Horasnn. IMS «lat St, Brooklyn, If. Y. Would like to mention the stations I have heard on a 1 bulb (W-Dll) set using a variocoupler, variable condenser. PWX, Cuba; WGAD, Porto Rico; WHAZ, Troy; KDKA, Pittsburgh: WIP, Phila.; WOO. Phila.; KYW, Chicago; WSB, Atlanta; WGM, Atlanta; WWJ, Detroit; WBZ {Continued on page 24) Digitized by Google

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RADIO WORLD WJZ's Children's Story Heard in British Isles TO Florence Smith Vincent, a charming and talented New York woman is ac- corded the distinction of being the first of her sex to be heard in Great Britain over the radio from WJZ, the Westingthouse Radio Corporation at Newark, N. J. At least she is the first woman to be heard talking and it was during one of her recent stores from "Peter's Adventures in Bird- land." that J. W. F. Cardell in Cornwall, England, not only heard every word of the tale but received a Christmas greeting from the young woman. So impressed was Mr. Cardell by the marvelous experience that he forthwith wrote to the Radio Corporation Westinghouse Station, congratulating WJZ and Mrs. Vincent on their achievement. WJZ is the only broadcasting station to be heard regularly in Europe. Other women's voices have been heard in songs as far as England but only in frag- mentary shape, and later at night. Mrs. Vincent tells her stories to the children at seven o'clock in the evening when the air is full, which makes the achievement all the more extraordinary. Mrs. Vincent, who has been relating her delightful stories of "Peter's Adventures" over the radio for the past year has re- ceived more than 4.0(10 letters from pleased listeners and these have come from all parts of this country and as far north in Canada as Banff. From Maine and all the other New England States, from towns as far south as Miami, Florida, from Texas, Iowa, Missouri and in fact from almost every state this side of the Rockies have come letters from young and old. And every letter has been answered either personally by Mrs. Vincent or through her publishers, Fred- erick A. Stokes Company. Mrs. Vincent has another distinction which might be mentioned in connection with her great success as a radio broadcaster and that is that she is the author of more than two thousand children's stories. Many of these have been compiled in "Peter's Ad- ventures in Meadowland," and "Peter's Ad- ventures in Birdland." A third book, "Peter's Adventures in Animal-land," is shortly to be published. These form an interesting children's library. More Work for NAA THE broadcasting of weather reports and market news from the Agricul- tural Department was transferred from the Washington Post Office station re- cently to Naval station NAA at Radio, Va. In all, NAA got eleven new schedules comprising nearly three hours a week more of broadcasting. This station now handles an average of 18 schedules of fifteen min- utes each a day, totaling approximately 25 hours a week or almost 4yi hours daily except on Saturday and Sunday. The new schedules are all on radio tele- phone circuit carried on the 710 meter waves. They include reports on live stock, fruit and vegetable, hay and feed, dairy products previously carried by the Post Office but now broadcast via land wire from the Agriculture Department, Washington. , Weather reports and forecasts as well as warnings are now sent twice daily by voice directly from the Weather Bureau, so that several thousand more recipients can under- stand the broadcasts, than get the code re- ports. It is understood that all work pre- viously handled by the Post Office stations will soon be transferred to Army or Naval Radio stations. A new schedule from the Civil Service will be handled by NAA every Wednesday evening at 7:25, so that a radio civil want ad broadcast will soon be in operation. Marine and Naval Band music will be continued each Wednesday and Friday even- ings. Chief Radio Man B. L. Moore, U.S.N., doing the announcing. A Real Opportunity OF late, there has been a general and marked improvement in shipping, and of course with the increase in the number of ships doing business, there naturally is an increasing demand for competent radio operators. All over the country there is need of radio operators, and on a canvass it was learned that 15 out of every 20 ama- teurs did not know enough of the rudi- mentary principles of the science to pass the examinations. The graduates of the Radio Institute of America (formerly the Marconi Institute), are placed in berths by the Radio Corpora- tion of America, of which the Radio Insti- tute is a part. The Radio Institute has not at present enough operators to go around and as a result there are many ships that are inadequately supplied with operators. The present pay of operators range from $75 per month and board, upward, depending upon the class of the vessel they work on. This pay, of course, is absolutely all clear, there being no deductions for expenses, meals, etc., and the operator is classed as one of the officers of the ship. This Institute was founded in 1909 to train operators for the American merchant marine, but it now offers instruction to any- one interested in the science of radio telegraphy andtelephony. Its graduates are under no restrictions as to where they may seek employment, although upon the ter- mination of the course they are placed im- mediately by the Radio Corporation. The requirements necessary for obtaining a position as a wireless operator are: 1st Gass Commercial License Certificate, either 1st, 2nd or 3rd grade; 18 years of age or older, preferably American citizens, or those possessing citizenship papers. There is no physical examination given, but the applicant should have no major disabilites. requiring the use of crutch or canes. Here is one of the best opportunities of seeing the world, and is also one of the most complete ways of obtaining an elec- trical education. Unique Washington's Birthday Broadcast FROM Washington a unique broadcast went out over NAA to the country on Washington's Birthday at 9 o'clock in the morning. Plans provided for the broadcast- ing of a salute to the Flag rendered by Army field musicians from Fort Meyer on fifes and drums. Arrangements undertaken by the Bureau of Public Buildings and Grounds provided, through the co-operation of the Chesapeake and Potomac Telephone Co., a land line and a pick-up instrument installed at the base of the Washington Monument where the celebration was held. This carried the music to the Arlington Naval Station. r^iliis ConwnuUnm WCompldai am HADIO RECEIVING SET—' TO own a good receiv- ing set wirhout Mag- navox equipment, is like having your house prop- erly U'itcJ and then using only small, feeble candle- power lamps in the sockets! VC hether placed in the aver- age living room or large dance hall, Magnavox Radio floods the dnirAi area wuh clear, resonant mutic or speech — its volume perfectly controlled from the Magnavox Power Amplifier constructed spe- cially for it. Combination R-3 Repro- ducer and 2 stage Power Amplifier (as illustrated!. R-2 Magnavox Reproducer with 18-inch horn: the ut- most in amplifying power, fc K jJ of fooJ Jolm «rry*tir>t The Magnavox Co., Oakland. California New York. J 70 Scv»nih A.emic Wnu lor KooUrt ,nM*mu,*t mj /AGNAVOX Icidio Tlhe Jhwcr Amplifier and Jicproduccr Supreme Digitized by Google

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RADIO WORLD AdrertiMBf Rates, Display, fSJO per inch, flSQjOO per page Radio Merchandising Oassiied Qqick-Aetioa AaVertisiBf , 5 cents per word Telephone Bryant 4796 New Radio Firms (The ntw firms and corporations men- tioned in these columns can be reached directly or by communicating with the attorneys, whose addresses are given when ever possible.) „Ai!tx„.Electrical Supply Company. (Attorney, N. B. Finkelstein, 51 Chamber, Street, N. Y. C) ^ Baker & Son, Mozart heatre Building, Elmira. Rube* Radio Manufacturing Co., S125.000: V. G. Swope, Raymond Swope, New York; W. W. Lecount, Brooklyn. (Attorney, Colonial Charter Co.) Parkway Electric Company, 1330 Commonwealth Avenue, Boston, Mau. E. R. LeManquais Company, Inc., 134 Worth Avenue, Plainfield, N. J. Radio Electric Company, 102 West 9th Street, Frank T. Scudder, prop., Fort Worth, Texas. Automotive and Radio Manufacturing; Corpora- tion, New York, $1,000,000 to $2 000,000. Cresson Electric Supply Co., Keystone Avenue, C. A. Klemstein, prop., Cresson, Pa. The Radio Shop, Ml Main Street, Westbrook, Me. Bluestone Electrical Company, Philadelphia. (Attorney, Corporation Guarantee & Trust Co.) Carroll -Edwin Co., 3217 Fourteenth Street, N. W.. Washington, D. C. Scott & Knies, Atler and Third streets, Hazle- ton. Pa. Chamberlain Electric Co., N. Y., to make radio instruments, $25,000; E. Gross, E. Bensamon, R. Kessler. (Attorneys, Rett & Kaminsky, 305 Broad- way.) Lee S. Geddes, 389 Madison Avenue, Albany, N. Y. Alcon Electrical Supply Co., N. Y. C (At- torney, S. B. Cardozo, 30 East 42d Street.) University Electric Co., 1353 University Avenue, Madison, Wis. M. B. Sleeper, publishing of radio books, in- corporated for $5,000. Directors, J. E. Whiting, E. Webster, G. O. Castell. (Attorneys, Avery * Whiting, 5 Nassau Street, N. Y. C) This Radio Mfg. Firm Works 24 Hours a Day THE fact that the radio industry is con- tinually growing was indicated the other day in a bulletin issued by the Alden Manu- facturing Co. of Springfield, Mass. In a letter to Radio World they say in part : "Our process has worked so that sockets being shipped to customers today were only raw materials yesterday. This is our third month of operating on three shifts, eight hours each. By this is seen that the factory is running 24 hours a day, and due to the fact that our orders are increasing at such an enormous rate, we are forced to increase our floor space over 25 per cent. We be- lieve that we are right in the claims that we are now the largest manufacturers of tube sockets in the entire world. It is partly due to the fact of our enormous advertising campaign, and wholly due to the quality of our product, which is the best that can be made, and in which no pains are spared to make it absolutely the best." Some idea qf the extent of this concern's development may be gained from the volume of sales. These have increased over 700 per cent in less than two years, and it is a con- stant rush to keep up with the ever-increas- ing orders coming in. Sales offices have been established in all parts of the country, and the company is also well established in Cuba, South Amer- ica, and Canada. There have even been considerable call for their products from Continental Europe. Radio Stocks (Quotations as of February 21, 1923, fur- nished by Frank T. Stanton c> Company, IS Broad Street, New York City, Specialists m IVireless Securities.) American Marconi Stamped 5c 20c American Marconi Unstamped $5 $7 American Tel. & Tel 123 123U Canadian Marconi 3M JK De Forest Radio 7 10 Dubelier Condenser S% 5% English Marconi com 11 IS English Marconi pfd. 11U 15M Federal Tel. Calif 5 6 General Electric 185*4 186 Hennessy Radio Pub 9 11 Mackay Company com 116*4 117 Manhattan Elec. Supply 55 57 Marconi Int. Marine 8 10 Radio Corporation com 3*4 3*4 Radio Corporation pfd 3H Jjij Spanish Marconi 1 3 Western Union 118 119 Westinghouse E & M 65 65*4 Move Because of Increase of Business BECAUSE of the tremendous growth in their business, Chas. Freshman Co., Inc., manufacturers of the well-known radio appliances, Antenellas, Micons and Variable Resistance Leaks, found their quarters at 97 Beekman street, New York, totally inadequate to meet the prevailing demand for their products. They have, therefore, taken much larger quarters in a modern, up-to-date building at 106 Seventh avenue, on the corner of 17th street, and are now doing business on an even larger scale. Production has been increased many fold and everything possible is being done to assure a maximum of service to all cus- tomers. Radio Wanted in Brooklyn Parks A radio set in every Brooklyn, N. Y., park has been urged in a letter to Bor- ough President Riegelmann by Arthur J. Olmstead, head of the Municipal Civic Service League of Brooklyn. Mr. Riegel- mann is reported to favor the suggestion. Dr. Lee De Forest Wins Cresson Gold Medal P RESENTATION of the Elliott Cres- 1 son Medal to Dr. Lee De Forest for his invention of the audion or three-elec- trode vacuum tube took place at Phila- delphia last week at the Franklin Insti- tute in connection with a joint meeting of the Institute and the Philadelphia Sec- tion of the American Society of Civil En- gineers. The special committee appointed by the Institute to investigate and report on the audion consisted of Charles E. Bo- nine, chairman, and Dr. George A. Hoad- ley, with the following consulting mem- bers: Gen. J. J. Carty, Dr. A. E. Ken- nelly, Major Gen. George O. Sqaier, John Stone Stone. The presentation address was delivered by Dr. Walton Clark. The report upon which the award was made says in part: "This invention for amplifying' minute electrical currents and pressures, called by the inventor the audion, is one of the most important ever made in the field of the electrical transmission of intelligence and through its development has worked a profound revolution in the art of radio communication. "Its use as an amplifier has made pos- sible the extension of radio communica- tion to distances hitherto impossible and has made available at the receiving end of the line a means of making the voice of a distant speaker audible by an un- limited assembly." Among others to whom the medal has been awarded by the Institute are Alex- ander Graham Bell, Sir William Crookes. Prof, and Mme. Currie, O. Mergenthaler, Sir William Ramsay, and W. C. Roentgen. Coming Events PERMANENT RADIO FAIR FOR BUYERS. Hotel Imperial, New York City. Open from September, 1923, to May, 1923. SECOND DISTRICT RADIO CONVENTION, Hotel Pennsylvania, New York City, March 1, 2, and 3, 1923. A Suggestion to Broadcasters Editor Radio World — Many of us (meaning radio bugs), like Jazz, and others like music, and it is our pleasure to sit at our receivers and fish about until we get just what we prefer, and when we get it we like to know who is giving the treat. But too often the broadcasting station neglects to give its call letters and we cannot gin the proper credit. Radio is good advertising for anyone whether it be an individual, a business concern or a city, and the broadcaster should not be so modest as to hide his light under a bushel. A statement through your medium might correct this and we, who try for long distances, would be relieved of an awful strain sometimes. Have 'em shout who they are from the housetops, so to speak, long, loud and often- Frank D. Fox, Minneapolis, Minn. It is a good suggestion brought out by Mr. Fox in the above letter. The Radio W<*lb would be glad to hear from others on the subject, especially from broadcasters. Our colnmm are open to you. — The Editor. Digitized by Google

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RADIO WORLD GALENA CRYSTAL —am in ajarial prepared aetal Ik Uaaanrtad IS*. All muuiKd. UaaSmuw. daeaee and labboro writ* for quantity prleae. We ahn ■aaefaetara Raete aorta t» ardar. PRCCtaiOM TOOL 4 MFft. CO.. IM jJejajt. B.V.O. Let Radio Radiate Your Home Llit Our PrtM 18.00 rtdarml Phonae 16.05 1.50 Kloancr Veml.r llliiillill .TO 1. 75 Bright Star "B" Bat- t.rl.a. II % rait 1.10 T.TO 43 Plat* Varnlor Cm- • imw BB T*» rail larate at an* aojtaai are (tree, aae the eeao laeraaa ml aaaV Tin Baete MaMata etok aankaa) are ■ ■ la red aad Oat BadU Balar PI ill an ara to Mea. Tiaa anno ara laaradad. Atoe*- *— *— ' Ik** or eiillaai aad aliieaaniMl Uata af aall lotaee are la a fain oica aaaor. Price »Sc Each THE COLUMBIA PRINT ten BROADWAY NEW YORK CITY AMATEURS. atMO »»B QATALOOUt ~B" aattartai That Laat Far flea Vaare Dart. ~B." Ittl Jereae A«a_ Mae Vara, H. V. Digitized by Google

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24 RADIO WORLD DX Nite Owls (Continued from page 20) A Pretty Good Record From C. Parkinson, Toronto, Canada IN your January 27 issue I noticed several very remarkable records, and hard ones to beat. These reports were under the heading, "With the DX Nite Owls." Well, here is my record for the month of Janu- ary. The stations are: WGY, Schenectady: WGR, Buffalo; WEAF, New York City; WMAQ, Chicago; WOO, Philadelphia; WFI, Philadelphia; WNOK, New York; KDKD, Pittsburgh ; WJZ, Newark ; WCAE, Pittsburgh; WLW, Cincinnati; WLK, In- dianapolis; WOR, Newark; WW J, Detroit. For all of these stations I can use a small Brown's loud speaker. The following are a list of the long distance stations that I have heard: WHAS, Louisville; WSB, Atlanta, Ga.; WDAF, Kansas City; WOC, Davenport; CSCG, Winnipeg; CKCK, Re- gina, Canada; WDAJ, College Park, Ga.; WCAT, Rapid City, S. D.; WDAO, Dallas, Texas; WCAY, Milwaukee, Wis.; CHAC, Halifax, Canada; WBAP, Fort Worth, Texas. This completes my list, all but these two KDZH, Fresno; KWH, Los Angeles. What do you think of these two for long distance work? All of the other stations 1 can tune in or out whenever I wish, all but the last two. And I have only heard these twice. All of latter stations are over 600 miles from Toronto. The circuit that I am using is regenerative. When I tune into our own local station CFCA you can hear it 40 feet from the horn. My aerial is 130 feet long, one wire, and 70 feet above the ground; the lead-in is 50 feet I think for a one-bulb set this is a pretty good record. (I use a WD-11 tube.) * * * Using Only One WD-11 Frssn WUttam Branthr. U1S Humboldt St, Bakerafield, Calif. I am sending you a list of stations I have heard in the past three nights. They are: 6BM, 6BAC, 6ZM, 60RE, 6XAS, 6BA, 6BVW, 6BO, KWH, KDYL, KZN, KDYO, KSL, KFBK, KHJ, KFEB, KFI, KFDS, KWG, KQW, KFAF, KMJ, KPO, KFZ, KLZ, KVO, KFCK, KGG, KFAY, KGW. . Another Home-Made Set DELICATE SOLDERING Both tba am aD §m» was* Is readily for this particalar purpose. solved by the THE POST SOLDERING IRON Platinum Heating Unit— Interchangeable Tips—Universal Current (Lars* and Small) Tee* Dealer er Write Awarded Carttteate of fcosMoeey. N. T. Evening Mail Radio POST ELECTRIC COMPANY, (Or. SB) 30 E. 42nd St, New Terfc Phone Clips, Crystal Detectors, Condensers Duplex Clips Two for 7c Poet Paid Special Price, 2 for 5c The moat depend- able and efficient Phone Condenser to be had at any price. Hade of high dielec- tric specially proc- essed varnish paper. .001 M.F.D. capaci- ty, and each con- denser is tested at 110 volts. Remem- ber that Fixed Con- denser capacity is necessary (or tube seta Hedden Place Machine Co. Manufacturer! of HPMCO WIRELESS PARTS 4* HEDDEN PLACE EAST ORANGE, N. X With this device Phones may be used in either aerie* or parallel. Unequalled for square bus wire work. No. 17 Crystal Detector, 27c each, Post Paid Assemble your own Crystal De. tector. Complete parts for panel mounting; unassembled, in envel- fi„:^T 3"' H'S""1 quality design fi nish. Heavy brass nickel - plated with Bakelite Knob ASSEMBLED No. 20 Fixed Condenser, Special 39c each Post Paid FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD Phase send me RADIO WORLD far. please find enclosed $ SUBSCRIPTION RATES: Stasia Cory S .1J Tare* aioatas 1.50 Six Mentha 1.00 One Y- "■ Issues) 6.00 A»M -'-it for Poretgm T -nadian Post- 1493 Broadway, New Yerk City. months, far which Janas W. To HERE are my records for a single-cir- cuit, home-made receiving set with which I have had remarkable success. It is very selective both for phone- or C W. On November 25 I heard 27 stations dar- ing five hours. These were: WJZ, WOR, WSB WGY, WIP, WGM, WHAF, KDKA WBZ, WDAF, WRR, WEAF, WMAK. KSD, WLAG, PWX, WHAS, WOC, KYW, WBAJ, WGR, WOI, WEAB, WNAC WDAP, WNAN, WOO, WOS. I have codes from almost all of these stations. I have heard over 100 since I constructed the set, and I am using only a single, 7-strand aerial, 25 feet high and 150 feet long. The vario-coupler was made by myself, and it works on wave-length) from 170 to 500 meters. All battery con- nections, as well as aerial and ground, art on the rear of this set, which leaves a very pleasing effect from front I used no shielding, as I found there was practically no body capacity effect when using the I. R. adjusters. The set is bus bar, wired with square tinned copper wire, which makes it very neat if care is taken in wir- ing. I am enclosing circuit of tuner and construction of coupler. I should be glad to give any other information. • • • Twenty-five an Evening in N.S. From Horace S, Oidfnc, New Glaaaow. Nova - Using single circuit regenerative and one tube I have heard the stations listed below: WJZ, WBZ, WOO, WIP, KDKA, WAAM. WGL, WHAM, CFCA. WBAP, WCM, WSB, WHP, CFCF, CKAC, CHYC. WGR, WBAN, WFI, WWJ, WBAK, WNAC WEAF, WHAZ, WMAK, PWX WKAQ. WDAF, WMAF, WMAC, KLK, WHAS. WBAF, KDOW, WGY, WRW, KHJ, WCAE WNAT, WQAA, WGI, KOP. WDAP, WJAX. WPL, WDAK, WOC, WLAK WFAB, WWB, WBU, WFAC WBAU, WNAN, WCAP, NOF, NSF, WJAZ, PBAN, KYW, WJX, WAAT. I •have heard as many as twenty-five in one evening and enjoyed them all. Di The Heart of the City From Charles KoMman, New York CHy A FTER reading the lists of many DX 1 x fans in your magazine I decided to send you my list. I am situated in the heart of the city. WAAQ, Greenwich, Conn.; WOC Daveo- ?ifTU2X#l: Deal Beach: WCAE, Pittsburgh; WIP, Philadelphia; WBZ, Springfield; WSZ Toledo; NOF, Anacostia, D. C; WLW, Cincinnati ; WWJ, Detroit; WDAP. Chicago; WGI, Medford Hillside; WNAC, Boston; WHAS, Louisville ; WHB, WDAF. Kansas City; WSB, Atlanta; WHAZ, Jroy: W£AA' Dallas: WEAN, Provi- dence; WEY, Wichita, Kansas; WBT, S,xrrI°4VeVN-.C: WSY, Birmingham, Ala; WNAP, Springfield, O.; WCAL, North- field, Minn.; WGY, Schenectady; WMAK Lockport. * * * All the Way from K. C. Krom Prank M. Psion, 210 W. KM St- Kaaaaa city The Sweeney Automobile School m Kansas City, Mo., lays claim to broadcast- ing records. They started broadcasting at 7. -00 p. m. Feb. 1 and broadcast until 7:28K 5' m,v, . * 2- They broadcast continuously for 12 hours and 28y3 minutes, and the engi- neers did not replace tubes or do any work on the set. Chamber of Commerce mem- bers spoke and Ted Lewis and his iatz band playing in the "Greenwich Villap Follies entertained. The Radio Bug reigned supreme from 2:00 a. m to 5:00 a., m and choir music was furnished by the Central Episcopal Church of Kansas City from 5:00 a. m. till 7:15. The pro- gram ended with a short talk by E J. Sweeney about the Sweeney School. igitized by VjOOg IC

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RADIO WORLD 25 UND MM TOOT PHONE* f«r repairs. All makaa gaaraataad. Btae enable aktmn TmM CABINETS Tmm. BmoUMBt Mahogany FtaWL 7x24 xafe your tfexrtar /or the S C. Iirpe. R. C BULLS Anm» Nnr York City A VVoiKsWtful OyiHM'laiailj Itje Mm Dlrlsleu of TBS &ADIO 0 Hit) RATI ON OF AMXBICA asetpl M DOT er I ilmiI enpnwnu la tMt Mitai as Wlnla Or mil bar men ear Graduates. Irtr—MeaU the l*KU nd threat* taklu either our HOMS STDVT m I ■NO mures In Baa* euuo lMtrriTUTa or Formerly Marconi /nttiruM Haw Task 0U7 RADIO MAILING LISTS 1.41* Mil Onkn, MMrtM U. a. ky (Mh aw M if»-*» • 14 ftaatte Mfn. wnrla* UJ. ky llllllb ear list, tiMt 717 Badle aaeety Jekkara, ewerles U. SVhr Settee, ear Hat til-** 14 Baate etettaas. par I tat MM 17 Mfn. «ka mm aat attaaikta >— atata Sadie tat*, eaTilet t4Je 1.444 Raata AajMaan aat tataMtrt at Sadta ^ M W. ADAMS STRUT OHIOASO. ILL. RADIO TOOL SET Sana CattfcwrMar Lane Naaa Pilar i TWa Sam Driven ElectrteWa Katfa Twaaaan FUe Witt SeMerlas Iraa KM 44.71 Witt Antaanilta Tan* eisai. at KM la Baa XB CO, IN Park PUea, Nam Yack Cat* The NtftJaat Short Wm Ta Only MLM at PP an 1 la. L. W. GOODMAN DREXEL HILL PA. aerrletaem, Pa, vrttae: Ltataataa OMAN, near* • nataa, "We la rateatta *Hk av aoOOMA... . art m II ailtas aat Iraa kaa f DENVER am la aa4 «aak tka akia. T.Ao« **V AC-SHIELD" ■*«« bring In DX rtiaai i*«s«ini The Invention of thia BaB-Bwenatie cuts out tic effects between vacuum tube*, orer- comes mtaratage coupling, which causes distortion and unnecessary n o i a e a which make it diffi- cult to tune in dis- tant stations — also guards tubes against breakage. Your tubes should have them. Attached in a minute // ynur denier cannot lupply von ire irtll thtp immediately by mail pOMlpaul on re- ceipt of $1.00. ORANGE RESEARCH LAB. 41 North Uth Straat Eaat Oraaga, N. J. RADIO WORLD PATENTS Alphabet Tells Use of Battery in Radio Set AT one time the various batteries neces- sary to the operation of a radio set could easily be distinguished by their type, as storage or dry battery. But with the wide use of the dry cell tube with which a dry cell does the work of the storage battery, the use of the letters "A," "B," and "C" is to be recommended. For no other reason than that tome dry cell sets contain instructions directing the owner to attach the 1^-volt dry cell to the filament posts, hundreds of vacuum tubes have had a short but merry life. To the novice a dry cell is a dry cell whether it be one of 22 or 2 volts, and it takes no longer to attach the higher potential battery to the filament binding posts than the bell ringing cell. The letters A and B were given to bat- teries in the filament and plate circuit, re- spectively, for no special reason. Likewise, when it was found that some tubes needed a supplementary battery in the grid circuit to make the tube work at the proper place on the characteristic curve it was only nat- ural that the method of lettering be con- tinued to call the new battery "C." — New York "Globe." Model Electrical Farm in Sweden A model electrical farm to enoo'iraRe the use of electricity in aericuh ire is being established near Stockholm. Sweden, and Semon-trations of elertrscal'v operated plows, harrows, harvesters, thre-hing machines, churns, separators, etc.. ws" be given. LT\ n SUPER. • lie- K. CRYSTAL -The V i b i TaaWa Oak* Will Make Year Ortetal aat Beaad Banf— 4ge gaah. ■eamaata. Frftyakata— tl.M. JAYNXON LABORATORY •7 otv aTacrr. atw van* mrv VARIOMETERS iv," aia aaTa Witt •tan, teatlal a git tM ta 444 M stars. Prompt Attention to atoll Order e B. B. JAR VIS, lac a. j. RADIO PANELS .Cat aaaattr ta atae aad attjaud atttkt It keam wt OT-w'En^fiViijH •task tan. lata taaiartal ataaaasse kg j install WILEY PANEL CO. tttt St. Oaakal Park Ave, Oklenea. ML CRYSTAL FANS Are you satisfied with your crystal, or do you want better results? MOLYBDIC GALENA A new detector just discovered is sensitive even when ground to dust. Send 50c for one of these wonder crystals. We will refund your money if you are not entirely sat- isfied. Phoenix Radio Laboratory Box 168, Phoenix, Arisona Novo B" BATTERIES NOTE THE INSULATE!) BINDING POSTS AND 7i* WIBr: CONNECTOR NOVO MFC CO. vy..S99 ST. e* so oiuaot« ji Ntv* V0«« MH«0O GUARANTEED REPAIRS VACUUM TUBES W.D.-ll not accepted jor repair Tear dealer thsaM kaaa. aat ■ ka asas aat mm* dtaeet ta HARVARD RADIO LABORATORIES a, i Digitized byVjOOQLC

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26 RADIO WORLD "The Little Wonder" FORIBOYS AND GIRLS CRYSTAL SETS Una—mbUd-Nmt Catches distinctly everything broad- casted within 90 miles. We also manufacture the "Little Wonder" assembled set at $5.00. GUARANTEED TESTED CRYSTALS Galena 15c Radiosite 20c Write for Free Catalog It Uata all our radio parts ant sappUs* Holloway Elec Supply Co, lac 2S8 Third Are. New York City From the Edge of the Aurora Borealis to Center of World (~)UT of the snow buried north was v^ sent the following letter, which helps our appreciation of this old world we live in: "Osaquan (via Ignace, Ont) "General Electric Co, Radio Station WGY, Schenectady, N. Y.: "Many thinks and greetings — shake! "On Saturday morning at 10 oclock, central time, we received a radio receiv- ing set and at 5 o'clock we were listening to your concert at Schenectady, N. Y. "You will not find us on any map you may have, but we are situated, geograph- ically, on longitude 92 west, and, I think, about 1,100 miles to the northwest of Schenectady. In the morning, we were only a lumber camp on the edge of the Aurora Borealis, and before supper time, STANDARD RADIO APPARATUS tamrns Every item listed in this advt. is guaranteed by us to be new and in original cases. Our guarantee of satisfaction or money refunded still prevails. Dlttttra** Less Sstaktn SIS.** Nt-sld W. D. II SMfctt IMS DMtinuk PkMM I.IS a. a. n iniimn BARGAINS EVERY DAY sis.se s.st 1.15 ■met* Pknw o.«0 $7.»» Herds* Patau, Nt. 17, •000 OHM 4.76 ••■It Otrssrauea TnaAnan U. V. 7 It. S.S0 •Ml* Otrptrailw Trasftrnert 0. V. 1714 1.45 Ftdwal Psttatltawtert I.4S KlMMr Vemltr BatMMt 7* Flttsersld ■■inlaw) vMk SlaJ. .7S CM* Huw Vernier Bat*- ttatt 1.25 GMkr Hawr Mala Mumli ••» ■■alt Sam, VerteM* Cta- *wn, mntnd faift Bakslltt tail alttt katk esd dial. 43 PUtt 4.IS 23 Plat* S.7S MSNIY ORDSR 0* OCHTIFIID OHIOK MUST ACCOMPANY ALL SUNBEAM ELECTRIC CO. Nt-ald W. D. A. B. C C*a« 43 Piatt Baldwl* Pktet*. Tyat "O", ■Mttr Bald** : PkMM 5.50 Amm Trssiftmtrt 4.SI Othaeal* Mtaldsd VsrlfsHrt. 3.16 Asdtrtte SMn btttted Varl- 3.35 S.SS autl Btaatlas. 43 Pitta 2.75 23 Put* 2.36 Triple Bank Wound Cofl for N. A. A. 153 to Silk Wire on BakaHta Tub* up uauur thla coil, brought In Havana, • SZ.7S which fare- OMDIRS 71 THIRD AVE. (Bet 11th and 12th Sta.) NEW YORK Farm Lifhtnuj Plant* at Bargain PricM. jERVICE DUALITY Standard Radio LOW PRICE RELIABILITY All Goods New, in Original Packages SEND FOR OUR 72 PAGE RADIO CATALOGUE WE GUARANTEE A SAVING OF 15% Reliable merchandise first, then price. We will refund, at any time, for Radio material purchased from us which is not up to standard and as represented. No Checks. No C. O. D. Add Parcel Post. Reference) Radio World. 577 MYRTLE AVENUE. Phone Proipect 2952-8168. BROOKLYN, N. Y. thanks to you and others, we became the centre of the world. "Your program came through perfectly and was heard in a room 16x20 as dearly as if you and your concert company were with us. "In the evening after your concert, we were in Minneapolis, Chicago, Denver, St Louis, Louisville, Davenport, Kansas City, Winnipeg, Regina and Calgary. In fact every place on the face of the North American Continent was contributing to our pleasure, and they were doing it as if it were the greatest pleasure in the world to do so, freely and without stint. "Sincerely yours, "E. Appleton." Radio Audience Builds Scenery for Dramas VERY listener constructs his own scenery when the WGY Players broadcast their weekly play from the Schenectady radio station of the General Electric Co. and the probabilities are that nearly everyone is seeing the play in a different setting. The listener hears a tel- egraph key and the lines refer to a rail- road station in a small village, as in the case of the first act of "The Traveling Salesman." At once is created in the mind of every fan a picture of a railroad sta- tion, and to him all the succeeding action denoted by the voices of the players takes place in the mind-picture of the listener. In the radio drama only sound "atmos- phere'* is possible. Telephone bells, clos- ing doors, thunder, an automobile horn, the whistle of a train or the whistle of the wind, the rattle of dishes or the rattle of a typewriter all help to convey pictures to the listeners, and these pictures are made fairly definite by the lines. Players of radio drama are handicapped by the necessity of conveying all emo- tion by the voice, by intonation and shad- ing. The real artist of the stage need not utter a word to express emotion; the clinching of hte hand or the twisting of t handkerchief are stronger than words. The radio audience of to-day gets hi drama exactly as the blind man formerly "saw" the stage play, entirely through the ears, but supplemented by imagination and experience. Radio drama is the direct op- posite of motion pictures ; the former de- pends upon sound, the latter upon sight It is reasonable to expect that the grow- ing popularity of the radio drama will re- sult in a revival of interest in the spokes drama. After every play presented by WGY Players the studio receives from 809 to 1,000 letters from ardio fans, express- ing appreciation and enjoyment. It is in- teresting to note that a great many of these letters come from those who have seen the stage production of the broadcast plays. Radio Story Told in Movies F TNSEEN things like radio waves, elec- trons, electric current and voltage are pictorially presented in a two-reel picture called "The Wizardry of Wireless" just completed by the General Electric Co. The unseen is made visible by means of ani- mated drawings and the result of the 2,- 000 feet of celluloid is a gripping, inter- esting and convincing explanation of the fundamentals of radio, the newest and most popular of arts. In this film the amateur is offered an exceptional medium for instruction. Re- sponsible radio clubs desiring to exhibit this film may have it free, except for transportation charges, by applying to Charles F. Bateholts, Director Visual In- struction Section, General Electric Co, ' ' N. Y. The film will be re- lict offices of the com- Tably reducing trans- Digitized by Google

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RADIO WORLD Body Acting as Antenna Detunes Set W-HLE listening to a broadcasting sta- ion the radio novice, studying the ex- terior mechanism of the receiving set, usu- ally discovers that he can change music into discordant squeals and squawks by putting his finger against the grid leak or trans- former, or merely by passing one hand near some part of the sensitive tuning apparatus, says the New York "Globe." If he seeks an explanation of the phenomenon he is told that "body capacity" causes it. This means, in simple English, that a charge of elec- tricity from the body has entered into the delicately adjusted circuit of the radio ap- paratus, thereby putting the receiver out of tune. Such an experience serves to give tangible evidence that the human body is in effect an aerial sharing with the wires of the radio apparatus a capacity to store electricity. In the technical phrase of the radio fan the body, like the wire aerial, has inductance and capacity. It transmits electricity as well as it stores it. It also offers a certain re- sistance to the passing of an electric current. And since these qualities are essential char- acteristics of the apparatus with which the radio operator traps the radio waves and brings the message bearing current to his receiver, it follows that the body is virtually an aerial. RADIO DISTRIBUTING * AUTO SUPPLY COMPANY formerly at 64 West 64th Street Announce* a chance of loratlao to 1 PARK PLACE NEW YORK CITY Wt aeetealm far say ti aar arwiaa aM Sway la sklansstt tm i tar watssMrs tBftt all lira aar arenet areetlaa. FREE DIAGRAM AT YOUR DEALER of the Fie welling Super Circuit FRESHMAN PRODUCTS tUpaetaOy Adaptable for tWs Cttewt VARIABLE RESISTANCE LEAK With .00025 mfd. Micon #| AA Condenser Combined. . Without Condenser... 75* 0 ANTENELLA No antenna or aerial needed. Eliminates all the inconven- iences in radio; operates from any light socket. Price only $2.00 "MICON" .006 Mica Condenser $1.00 .001 Mica Condenser 40c OTHER "MICON" 8IZK8 Slse Price Size Plica ....$SJS fut .» ma ja LSI At year dealer'*— otherwise aead pur- chase price and you will be •applied without farther charge. A dlagrasa ef the FlcwelHag -gaper" CI remit seat free if year dealer eaat aapply CHAS. FRESHMAN CO., INC. 106 SEVENTH AVENUE (Nato Km M*tn) NEW YORK CITY COMPLETE YOUR FILES OF RADIO WORLD FOR MB el aUees WarM ara I I ■ ■ s eaareer al the Haaa. Wa No» I ee date at ftJtaaa cones a earnr. Aar RADIO WORLD. MM Rraadwoy. Haw Yeah Otr THE Just Off the Press! Vol. I. No. 2 RADIO Price 25c Mailed CONSTRUCTOR BUILD YOUR OWN SET Thia new edition al TftE RADIO CONSTRUCTOR (Just off the press) Illustrates and hdly describee tea most popular mad Full and complete nutrocbone for tha conetrucbon al FLEWELLING REFLEX REINARTZ HONEYCOMB ■ recrtpt al only a loop aerial receiver, And Many Other T**1*d Circuit* Thia ia tha booh you have been waltta* tar. Cat It today from your dealer, or It wffl ha mealed roe Ntwau'i Radio Plana alao tell how ta make a crystal receiving eet a super selective rerenerarive tauter, wave regenerative set. medium wave tuner, radio frequency amplifier, etc.. sheets 17x22"— 2Sc each. DEALERS! WRITE FOR QUANTITY PRICES! S. NEWMAN & CO., Publishers, 74 Dey St., Dept. W., New York City Digitized by LiUU^k

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28 RADIO WORLD DO YOU WANT TO BUT, SELL OK EXCHANGE RADIO OE OTHER GOODS? DEPARTMENT AT b A TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department is intended for every**: (changing or gentraj merchandkinc in tSM every week. Advertisers will get a tea-day on the newt-studs ten day* alter copy foick action on short exc covering the buying^ radio field. Readers of RADIO WORLD will find that it pays to read these < hero that is, copy received for this department will appear in RADIO WORLD of 10 The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. it 5c per word including address), 10% discount for 4 consecutive insertions, 15% for 13 consecutive huertiont (3 months). Changes will be in standing classified ads. if copy is received at this office ten dayt before publication, RADIO WORLD CO, 1499 Broadway. N. Y. C (Phone, Bryant 4 INCH HARD FIBER RADIO TUBING, ant length to 4 It., 20c per ft. Variocouplers, $2.25. Radio Assembly, 110 Valley St., Joplin, Mo. ' THE IDEAL RECEIVER tunes with SINGLE CONTROL. No variometers, variocouplers. taps or switches. Cheapest to build. Particulars. ROKAY ELECTRIC COMPANY. Ingomar. Ohio. RADIO-APPLAUSE Post Cards. Encourage broadcasting by such acknowledgment. 2 dot en, 2Sc, postpaid. D. J. SPANGLER, Elkhart, Ind. AGENTS— Are you interested in radio? If so drop us a card. We have a proposition no live agent should turn down. Meets the needs, of 90 per cent, of the public. THE WILKENDA CO.. 500 Fifth Avenue, New York City. Dept R.W. GREBE RECEIVER AMPLIFIERS, cheap. IRVIN MAURER; Bethlehem Prep.. Bethle- hem, Pa. IF YOU ARE A REGULAR RADIO fan and like to hear the stations in the four corners of the United States come in with a bang, then you will want the Flewelling Circuit. If you do, send 15c for RADIO WORLD, issue of Feb. 27, which contains complete description and directions for the manipulation of the cir- cuit. RADIO WORLD, 1493 Broadway, New York. DO YOU WANT TO SAVE MONEY in making your set? Send for the Jan. 27 issue of RADIO WORLD, containing a full-page draw- ing of how to make filament control rheostats, as well as an easily understandable text, which makes the construction easy. 15c a copy, or atart your subscription with this issue. RADIO WORLD, 1493 Broadway, New York. EXCHANGE LETTERS with friends everywhere Pleasant pastime. Information far stamp. Sasith. Boa 3125. M. Portland, Ore. GUARANTEED Radio "A" Batteries, 40 am- pere hours, $12.00. 4" hard fibre tubing. 30c. per foot. Variocouplers, $2.25. RADIO ASSEMBLY, 1109 Valley St.. Joplin, Ma EXCHANGE JOLLY. INTERESTING LET- rERS through oar crab. Stamp appreciated. Betty Lee. Inc.. 4284 Broadway, New York City. ELECTRIC MAGNETS, 98c.; Vernier variable Condenser, $1.48. Garth Heckman, Ft. Recovery, Ohio. FOR SALE— Regenerative Receiver in cabinet, $22.00. Remler detector panel, with tube and B battery, $12; Remler amplifier with tube and B battery. $12; Murdock 3000 ohm phones. $2.50. All in perfect condition. Robert Van Vleck 116 Chestnut St.. Liberty, N. Y. HOW TO REPAIR Vacuum Tubes. Complete literature, $1.00. Box 103, Station C, Toledo. Ohio. TWO one stage amplifiers, Acme, $8; Remler, King Amplifying horn, $7. Condensers. J. Rich, Hobart, New York. A COURSE IN MECHANICAL DRAWING— By Louis RottUHori. The anther hat written a moat practical book on the subject oi Mechanical Drafting. It folly explains the art ei Drawing, Lettering and Dimensioning. It la, by far, the moat practical beak ever published on this sub- ject, for use in day and evening schools, and more especially adapted for the teacher and tar sell Instruction. Fifteenth edition, revised and enlarged. PRINT, Fully nhutrated. Oblong. COLUMBIA ', MM Broadway. N. Y. CL Prise, SUA, HOW TO BECOME A SUCCESSFUL ELEC- TRICIAN—By Prof. T. O" Conor Sloaae. An in- teresting book from cover to cover. Telling in simplest language the surest and easiest way to become a successful electrician. The studies to be followed, methods of work, field of operation and the requirements of the successful electrician are pointed out and fully explained. 202 pages. Illustrated. Nineteenth revised edition. Cloth. Price, $1.50. The Columbia Print, 1493 Broadway, 1 * York City. BROADCASTING MAP of the United States appeared in No. t. Seat on receipt oi 15c, coin or start year subscription from that aa for SI issues). RADIO WORLD, MM RADIO WORLD New Yes* STUCK T— Let me solve year Radio i stalling problems. Service charge, 2Sc par aaestisa. Fred- erick Barber, 2M Jasper St, gy rawest, N. T. HAVE YOU SEEN ITT My unasoal foRy il- lustrated radio catalog is complete. Only a earns. N. E. Ristey, Spring Grove, Minnesota, FREE APPARATUS FOR SECURING SUB- SCRIPTIONS FOR "RADIO." Write today far complete list of premiums and oar special sub- scription offer. "RADIO," Pacific Bldg., Saa Francisco, CaL BATTERIES— Edison Storage 71 -- r : . a Jit Battery Elements, 5c per pair; 14 will make one 2L5 volt Battery. GILMAN'S BATTERY SHOP, Chelsea Sq., Chelsea, Mesa. MAKE MONEY AT HOME MAKING TOYS and novelties. Send 5c for samples snd particu- lars. New Specialty Co.. 417 E 71st St., New York PATENTS PROCURED AND TRADE MARKS REGISTERED— Advice and terms noon request Robb. Robb * Hill. 1403 Hanna Bldg., Cleve- land. Ohio; 942 McLachlan Bldg-. Washington, D. C. ADVERTISING SOLICITORS to represent RADIO WORLD. The best quick action radio advertising medic -n. State territory you can cover. Tell us about your past experience. Write Fred S. Clark. Manager, RADIO WORLD, 1493 Broadway, New York. NEWS AND GOaaiP OF THE STAGE Seel 10c for specimen cany of NEW YORK STAR, the great flhsstrated theatrical weeaJjr. $441 four, $2.00 six months, (LOO three a* ork Star Co., 14*3 Broadway, N. Y. VACUUM TUBE RESULTS WITH A CRY- STAL SET I Cover distance with a "PT" ULTRA- SENSITIVE CONTACT in your crystal detect- or. Beats gold and other ordinary catwhiskere. DOES NOT JAR OUT. Mvrle Wood. Rhineland- er, Wisconsin, writes: "That *PT* Uln five Crystal Detector Contact 1 purchased te sure a wonder. Using the "FT* rnatart sad galena, I have heard over 43 different Broadcast ins stations, up to l.ttt miles distant." The "PT" has received code 3,300 miles. Price, only twenty-five cents. "PT" CRYSTAL CONTACT COMPANY, Box 1641, Boston. RAND-McNALLY RADIO MAP OF UNITED STATES— Is 28 x 30 inches in size. The locations of broadcasting stations are shown by distinc- tive symbols. The call letters of each station are given, also the wave lengths of each. The Radio Districts with numbers are shown in red and the Radio Relay Divisions are in blue. Time rones are included. Alphabetical lists of stations and alphabetical lists of call letters are in the margins. Convenient pocket form with cover. Price, 35c. The Columbia Print, 1493 Broadway, New York City. MODEL MAKING— By Raymond Frauds YatesT A new book for the aseoaaaic and model aaakar. This is the first book of its kind te be pubtlabad in this country, and an these interested ia model engineering should have a copy. The first eight chapters are devoted to such subjects as Silver Soldering, Heat Treatment of Steel Lethe Work, Pattern Making, Grinding, etc. The remaining twenty -four chapters describe the construction of various models each as rapid fire naval guns, sjpeed boats, model steam engines, turbines, etc. ♦» °?t»* m Ohutrationa. Pries, $3. S3. The Columbia Print, 1493 Broadway, New York City. OLD MONEY WANTED— $2-00 an paid for hundreds of Old sad Odd all old money. Send 10 cents far Hew Com Value Book. 4x4. Yea may ha i oaiaa. Get posted. We pay CASH. Company. Ave. S3, La Roy. N. Y. BACH Can AMATEURS— LOOK I Sand in 15 RADIO WORLD for issue of Tannery 20 esa- taining panel layout, hookup and foil explanatory data on the construction of a D-X receiver, which simply lays the long distance on year table. Or start your sob. with that lessee. RADIO WORLD. 1493 Broadway. New York City. WIRING A HOUSE. By s boose already baflt| tails about wiring it; where te be use; hew te run it according to fact, just the laJormanon you ^"preSt* W B'rasdn;, H. If. to start coltJS- C Prise, ATTENTION. Amateurs 1 1 Have you seen lbs RADIO WORLD'S page at hook-ope 'fa. the Oat 21 issue? 15c a copy or atart voter snbecrtpdss with that Number. Many people are writing is for the book-ape listed hers. RADIO WORLD, 1«S Breeders?. Now Yes* Cfty CASH FOR OLD GOLD, Pmttaam. SQrst, Diamonds Liberty Bonds, War. Thrift, Unossa Postage Stamps False Teeth, Maajneto Posts. Jobs. Any Valuables. Mail in today- Cash son. return mail. Goods returned in ten days if yeerrs not satisfied. OHIO SMELTING CO- 337 Hip- podrome Bldg., Cleveland, Ohio. RADIO TUNING RODS , (Patent Applied For) Eliminates body capacity when toning la. With Tuning Rod in your hand yon can step unnecessary noises and shrieking. Every rad» Ian should have Radio Tuning Rod. Send B cents stamps or money order. Radiophone Co, SOS Fifth Avenue, New York City. ,opoo~ ufactore of vam- »"r^^R^oELECJ,UCAH DICTIONARY— By Prof. T. O^ Conor Sloaae. Jnet ieened aa en- tirely new edition brought up to date and grmtly enlarged— as a reference book this work to beyeaJ comnarison, aa it contains over 700 pages, nearly 500 Illustrations, aad definitions otobout (JO distinct words, terms snd phrases The asfisi £m ^,m"el^ce?'^d lustrations. (See page 18 for fuller deecr^tinej j^Yo^aly* U "* TWENTIETH CENTURY BOOK OP RECIPE*, FORMULAS AND PROOrASES-Rdited byGsSJ ner D. Hiscox. This book of 800 paces a the . complete book of recipes ev ~ thousands of recipes for the i mbl» »rticles for every day use. Hints, bets*, prscticsl Ideas snd secret processes are reveahd within its pages. It covers every branch of the useful arts snd tells thousands of ways of aaakiaf money snd is jnst the book everyone should bars at his command. The pages are filled with mat- ters of intense interest snd immeasurable prac- tical value to the photographer the perfumer, the painter, the manufacturer of ginee, pastes, cements snd mucilages, the physician! the' dres gist, _ the electrician, the dentist, the engineer, the foundry man, the machinist, the potter, tat tanner, the confectioner, the chiropodist, the mas ufacturer of chemical novelties snd toilet nree- arstions. the dyer, the dsetraalater. the sssaaseke. the engraver, the Mass worker the ■oid-bsstcr, the watchmaker, the Jeweler, the ink nsaanfac- turer, the] optician, the farmer, the_ dairyman, tat shies nat you wtB fix! ne of informs tios paper maker, the metal worker, the soap mi and the technologist in general. A book to wl you may turn with confidence that yon wfB what you are looking for. A mi: up-to-date in every respect, ^""^-rns an im- mense number of formulas that aim jam oaakt to have that are not found m any otrx New edition. 807 octavo pages. Cloth Price, $4.00. The Col um bis Print, 1493 Braedwsy. New York Chy. wmf Digitized by Google

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RADIO WORLD 29 Rexite Synthetic Crystals Sensitive over the entire surface. Price, including special catwhisker, See. Dealers — Write for unusual proposition. THE AIREX COMPANY 237 Centre Street New York Da/fin &lestlons nuUiU Answered Let the Radio Quiz Book answer all your questions about radio. This book contains M questions and answers— detailed descriptions of radio equipment and how to take care of it, and explanations of radio terms, symbols, diagrams, formulae tables, laws, regulttions, etc It it • book of ready reference everyone interested in Radio should have. Send for the Radio Quia Book today. For • ■hort time we are selling it for $1.00. Ma with $1.00 now I fail letter NATIONAL RADIO INSTITUTE, Dept. R.WJL IMS Pennsylvania Ave., N.W, Washington, D. C. Air-Muse Receiver. $£.00 Range 50 to 500 Miles. . . . " The famous AIR-MUSE receiver consists of Oak cabinet, bakelite panel, selective and primary tuning. So simple a child can install and operate it. Broadcasting sta- tion programs heard perfectly. This re- ceiver is absolutely guaranteed or money refunded. Sent post paid anywhere in the U. S. A. on receipt of Express or Post Office Money order. 3000 Ohm double headset UM Set complete as illustrated $12Jt All other radio accessories at manufac- turers' prices. Detroit Radio Company ONE WEST 34th STREET NEW YORK Dep't W Ifs the contact that counts The special phosphor bronze clip, a* the Vaald W. B. llSocket i perfect contact regardless of any variation la tabs prongs and bases. Moulded from gen nine Condon site, these sockets are made far nse with the famous W. D. 11 tabes, operated by a single cell battery. The Na-ald De Lose V. T. Socket Is ef highest quality throagkeat. Its laminated p h • s > h • r bronze strips press firmly with a side wine action cm the contact pins, keep- ing surface clean and in- suring perfect contact. Thesm locket* retail at 75c each Send sump for dial, small-space socket, con- denser and R. P. Trans- former circulars. Mden MannfMbjitai Co, torsierly ALDEN-NAP1ER CO. Dart. L M Wills* St Ssrinilbld. Maw. WJZ Heard Constantly in the British Isles THE constant reception of WJZ't signals in England makes it unnecessary for the Radio Corporation-Westinghouse Broadcast ing Station to run a trans-Atlantic test. This fact became known recently when Geoffrey E. Duveen, Director of the Burndept Ltd., of London visited Station WJZ, and who stated that the signal strength of WJZ is so strong phonograph records can be made of it in the British Isles. Mr. Duveen is a most enthusiastic radio telephonist. He demonstrated the new science in tie British Isles by a unique method. He took his fishing rod and a receiving set in his Cadillac Sedan and toured the British Isles. When he came to a large tree he would cast his line over it and then reel in his line until the eight ounce lead would give him a tight line. He then attached his copper wire to the stretched fishing line, drove his Cadillac several hundred yards and tuned in his radio apparatus to catch the music in the sky broadcast from America. J. H. Redley, a Burndept engineer, was the first Englishman to receive a continuous broadcast from an American- broadcasting station, namely an Estey Organ Recital from New York City broadcast by WJZ using remote control wires. Mr. Duveen, who has been a candidate for Parliament, stated that the British Broadcasting Stations copied after WJZ's programs beginning at 5:30 with Bedtime Stories, followed by news bulletins, weather forecasts, musical and speaking programs. Upon his return to England, Mr. Duveen will try to arrange a trans-Atlantic tesr. for 2 LO, the Broadcasting Station in London, the test will probably be run in the early part of March at 1 :00 A. M., or 7:00 P. M., Eastern Standard Time, WJZ, standing by three nights during this period in order to give the American amateurs an opportunity to hear the first broadcast from the British Isles. The trans-Atlantic unofficial test requested by the British amateurs was heard in sev- eral parts of the British Isles according to Mr. Duveen. The newspaper clippings from English papers that came to the attention of WJZ checked up in detail with the pro- grams broadcast. This unofficial test was also heard in Haiku, on the Island of Maui of the Hawiian group, Or about 100 miles southeast of Honolulu by Jack Costa, who reported hearing the British National Anthem. The report from Haiku brings to light a most unusual program broadcast from WJZ. Win. D. Ager, the New York representative of Selfridge, through whom the unofficial test was arranged, distributed pencil copies of "God Save the King" to WJZ's announcers and operators. The im- promptu chorus was made up of the British Consul General, Groster Armstrong, and his wife and daughter; Milton J. Cross, tenor, announcer AJN; Vaughn de Leath, the "Original Radio Girl." and Thomas Cowan, announcer ACN, a light opera tenor, took high C whenever it was due, while George Bliziotis, Chief Operator, added a slight Greek accent to his bass voice. The chuckle of the special policeman was neutralized by the dialect singing of Alvan Simmons, who is slightly darker in complexion than the Hawiians. The accompaniment was played by the Black and White Melody Orchestra. Ezry Sez: NOW, that this here radio's gettin' so gol-durned pop'lar, I hev ter put a set in th' hennery, to keep those blamed hens up to the market price of eggs. "Saturday night uster be courtin' night 'round these here parts. Sence radio's come to town, the younkers don't go roamin' 'round the fields anymore, they say they'd ruther 'listen in' then walk out." "Betsy, our caow's givin' more milk these days sence she heard that the price of prime beef's gone up." RADIO. FREE Jain bay's nulls dab. Bsmsm s radls exsert. Msaber. •his FREE to thsss whs writs st inn. Asanas NstlsssJ Bay' i Radls Club, 200 N. Stated St.. Mlsssssslls. Miss. Excellent 43 Plata Caadsntsr .001 $1.30 Exaallant .0005 Varlsbls Osndsaasr LIS Varlsnatara. Bsldwls Style. Wsad 1.50 Kiss Asjplitaae Laud Talkers 4M Fasr-Cas-Llites Multlsbassa 2.00 CASH WITH ORDKB Radio Engineering Co. 2 West ath Street New York Ctty 12000-OHM L,M P ,M 75e. RESISTANCES IN STOCK For the New Super Circuits RADIO STORES CORPORATION BOBBINS RADIO DESK A Place For Tour Radio Set Separate arranged closed compartments for Batteries, Head Sets, Tools, Extra Parts and other Appliances. Useful and ornamental in any home with a receiving; set. In oak and mahog- any finish. Send for Illustrated Literature. BOBBINS WOODWORKING CO. LIBERTYVILLE, ILLINOIS MULTIPOINT (Patent Pendlns) A Synthetic CRYSTAL DETECTOR sensitive ever Its entire surface Eliminates all detector troubles. Extraordinary clearness and volume. Endorsed by radio euxirta and preaa. SV>ld In sealed paekasee only. Jola the eier-lnertaalns Ruaonlta fans. 50c RUSONITE CATWHISKER i To the Man with an Idea I offer s comprehensive, experi- enced, efficient service lor his prompt, legal protection, and the development of his proposition. Send sketch or model and descrip- tion, for advice as to cost, search throufh prior United States patents, etc Preliminary advice gladly furnished without charge. My experience and familiarity with various arts frequently enable ma to accurately advise clients as to probable patentability before they fo to any expense. Boat let ef raJusbk Informatics, and farm far properly duwlealni your Ides, free en request, write tansy. RICHARD B.OWEN.Pstsst i 32 Owes Bundles. Wasblaftee. o. 0. 2270-f Weehrart* Bis... Nsw Vsrk Orty

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30 RADIO WORLD Get Them While They Last! Any copy mailed for 16c Seven copies, $1.00 Useful Technical Articles Published in Former Issues of Radio World fi-Watt APRIL 1. A 600-MUa Radiophone B Tub*, by Prank A. HahoeL "Tall Me, Please, How Will ploying This Sot 1 oelveT" b? K. L Bragdon. Short Cuts In Receiver-Circuit Design, by of Inductance Colls, by i Simple Fred. Chas. O. Rooa. O. Fred. Making a Short- Wan Regenerator, Chas. Ehlert APRIL/ a. Do Ton Know Your Receiving Bqulpeuant, by James D. Gordon. Why a Crystal to Cullsd a RaetlBar. by Wal- ter Emmett la Radlotelephonv Dependable* by O. O. Rooa. Mounting Crystals In Tour Detector, by B. L. Bragdoo. Ampli- fication, by C. White. The Beginner's Catenblam, by Bdward Un- wood. Locating Tour AerlaL by Harold Day. Facts for Beginners, by Fred. Chaa. BhlarL JULT 22. Whan Tour "Movies" Come by Radio, by Stan- ley Bryant. Underlying Principles of the Vaouum Tube, bp Qeorge W. May. Practical V-T Detector Panel, by Frederick J. Romford. Revised Radio Dictionary, by Fred Chaa. Bhlert. The Beginner's Cateehlsm, by Bdward Lla weed. Importance of Aerials to Radiation, by C. White. JULT SB. The Vaouum Tube as a Transmitter, by Charles H. Plath. My 20- Kilowatt Tuba and Its Uses, by Irving Langmulr. Importance ot the Capacity Switch, by hi L Bragdon. The Truth about Lamp-Bookat Aerials, by Harold R. Hart. AUGUST 6. How to Construct and Operate the Armstrong Soperregenerstlve Circuit, by John Rant. Using Radio Frequency to Usual Bangs, hp George W. May. Things Every Radio Faa Must Know, by B. Hawley. Revlaed Radio Dictionary, by Fro Bhlert AUGUST 13. The Work of the Audio-frequency Transformer, by George W. May. Practical Measurements of Capacity and In- doctanoe, by W. A Dickson. Experimenting with Armstrong Circuit Pro- dooea Unusual Hook-up, by Dr. O. S. Kelly. How to Secure Perfect Regeneration, by Fred. Chaa. Ehlert AUGUST 10 How to Build a Portable Field Busier, by Do Witt H. Thompson. Using Two Tobea for Receiving, by C. White. The Storage Battery as an Important factor In Radio Reception, by Donald Van Wyek, The Use of Capacity in n Circuit, by W. May. The Beglnner*a Catechism, by Edward Unwood. AUGUST SB How to Build s Splder-Web Reostver, by Frederick J. Romford. My Detector and One-Step Amplifier, by Fred. Chaa. Ehlert The Beginner's Cateehlsm, by Bdward Ua- wood. Hints for Fans, by C. F. Rye. SEPTEMBER 2 Generating C-W for Transmission, by O. White. Wonders of Radlo-Prequeaey Amplification, by H. S. Potter. How to Connect the Bleetrlc-Ltght Socket Aerial, by John Kent SPECIAL OFFER FOR A LIMITED TIME ONLY AT GREATLY REDUCED PRICES VARIABLE CONDENSERS I Plate Variable Condenser* ILK 11 Plate Variable Condenser*. SLS a Plate Variable Condenser* tut 41 Plate Variable Condensers «JS J Direct from Factory to You ORDER AT ONCE. CASH WITH ORDER GREENLEAF RADIO CO. Dept. 21 34 Merchants Row Practical Circuits for Regenerating Laud Ms- nals, by O. 8. Kelly. SEPTEMBER 0 Radio Ideas for the Amateur to Teat Oa by Carl Maasoa. How to Make a Practical Wave- Meter, to Frederick J. Romford. How to make a Honey-Comb Coll wtth n Tee- Stage Amplifier, by Fred. Chaa. Bhlert. Perfect Sbort-Wave Radio- Frequency Asa*- ■cation, by George W. May. _ SEPTEMBER 18. How to Make a Two-Tube by Frederick J. Rumtord. Methods of Amplifying Radio Signals, by A Bradbury. Voles Distortion In Vase tun-Tube by W. A. Dickson. Charging a Battery— from a ,._ Point of View, by Marina Thouvala. Working Diagrams for Beginners. SEPTEMBER 28, 1922 „ N*w ,7_.T, Hook-up Worth Tenting Out, t; P. F. Metsler. New Method for Lighting Filaments, by C White. Why the Radio Compass Is the Flghttai Element of Science, by Ort heron Gordon. Complete Tsble of Symbols Deed la Rails Reception, by Fred. Chaa. Bhlert. The Radio Primer, by Bdward Unwood. Complete Method tor Building an Bhctret- Detector Unit, by Experts ot theUsntt Bute* Bureau of Standards. , 8EPTBMBBR SO. 1922 Increasing the Wave Lengths of a Receiv- ing Set, by George W. Mar ' if* l™P°rt»«>ce of tbeVarlometer to a It eelvlng Set, by Donald Van Wyek. ^ Soeeeaaful Stunts of an Amateur Radiant, Employing Jacks with a Two-Stag* Ampli- fying Receiver, by Fred. Chaa, Bhlert OCTOBER 7. Superheterodyne Receiver na Applied ts tat Armstrong Superregenerative Circuit, by Chanel R. Leuts. . Constructing n Radio- Frequency Bagi earner by C White. Why the Open Antenna b Beat tor the Bash LUteoer, by C D. Wagoner. Broadcasting Station! of United States aaa Canada. The Radio Primer for the Beginner, by Lyai Brooke. ~ — OCTOBER 14, Neat Home Made Tuba Socket, by Gordon 1 Arthur. Veeaela Now Guided Through Fog by Re* S^?°! w R»d»telegraphy, by Otherus Coram What Makee theTlecefver Work, by DoeeU Van Dyck. Using the Vsriocoupler in a Short- Wave » cover, by George W. May. Regenerative V-T Receiver for Short Warn by Fred. Chaa. Ehlert. _ . OCTOBER ZL by (f'wWte. Pr0Temen** *"dio Kccei,u1' Chaa SEhfert YOU' Gronod Cbn»ection, by Prei How Radio Waa Installed in Our Home. Br Hattte Brigge Hartmsn. One- Tube : Regenerator Hook-up for Laud Suja, by Harold Day. Every Radio Set Haa a Reliable Range, by Jets Kent The Theory of Radio Communication. Br Horace Beers. A , , m OCTOBER a. ,A «?"5Lp,e Super- regenerstive Receiver, by sto- ol d S. Potter. Vacuum Type of Arrester Safe, by Fred. Cass. Ehlert. How to Make Your Aerial Function, by Horaai Beera. How to Avoid Interference When a MO Mdsr snd s 400 Meter Station Are Operating Sbaal taneooaly, by C W. Horn. „ . , NOVEMBER 4 Receiver for Amplifying Weak Sigaala. by Urn- ace Beera. How to Learn the Code, by Ortherua Gordsa Digitized by Google

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RADIO WORLD MMy Sunshine9 Friend" "Jt^O give nature a gentle boost; to bring sun- shine where dull care casts its shadows; to know the charm and kindness of a cup of good tea — I rec- ommend my 'sunshine' friend— Ridgways Tea." AWARDED THE HIGHEST HONORS OBTAINABLE Gold Medal Smn Frmnciaco 1915 Grand Prize San Diego 1916 f^dffwqysTea Orange Pekoe Tea Sold in 1 lb., % lb., % lb. and 15c Tins A GENEROUS SAMPLE WILL BE SENT ON REQUEST AdJrr-.tr Rldfwya Tea Co.. Dept. B, 60 Warren Sfreef, Wrw York. The Finest Tea the World Produces

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RADIO WORLD IF YOU ARE INTERESTED IN RADIO YOU NEED THESE BOOKS RADIO BOOKS THAT HELP YOU Telling How to Operate a Radio Set — How to Build a Set — Principles of Vacuum Tubes and Other Radio Problems Radio Hook-Up* Br M. B. A bode thst gives 70a sot only dear dia- grams for all kinds of telephone and tele- graph receiving and transmitting sets, bat simple descriptions of each circuit shown for notes of results obtained. PRICE Tic Construction of New TypeTrans- atlantic Receiving Sets By M. B. SLEEPER There is a peculiar fascination about re- ceiving radio meaaages from the high- power stations of England, France, Ger- many, Russia and Italy, as well as those located in the Pacific Ocean and the Orien- tal countries. Several types of simple re- ceiving sets for this purpose are described, with detectors and amplifiers to accompany them. Suggestions are also given for oper- ating relays and reproducing the signals 00 a phonograph. Schedules of operating time for high-powered stations are given. In addition, there ia some valuable data on home-made wavemetcrs for testing and ex- perimenting PRICE Tic. Wireless Telegraphy and Tele- phony Simply Explained By ALFRED P. MORGAN One of the most complete and comprehen- sive treatises on the subject ever pui >lished. A study of its pages will enable one to master all the details of the wireless trans- mission of messages. The author explains in simple language thr theory and practice of wireless telegraphy and telephony. 154 pages, 1S6 engravings PRICE SI St Design Datajor Radio Traiismitters and Receivers Br ML B. SLEEPER The only book that gives tables and data for designing, receiving and transmitting apparatus so that you need no knowledge of mathematics. It's the first book a be- S inner bays after he has learned the use of is phone receiver PRlCE^lc. Construction of Radiophone and Telegraph Receivers for Beginners Br ML B. SLEEPER The man who wants to feel the real thrill of accompuahment, and who ia not satisfied in the merely making use of what others have done for him, builds his own radio apparatus. Radio men can follow the data in "Radio Phone and Telegraph Receivers" with full confidence, because each piece of apparatus described waa first made, tested and found efficient before the final design waa accepted. Special receivers, both crys- tal and audion, are shown in detail. Regen- erative circuits aa well as audio and radio frequency amplifiers are described with clear photos, diagram s, and working draw- ings prepared especially for the novice and the mas who wants to receive the radio telephone broadcast. A special feature ia the phonograph type radio set and the loud speaker. Fully illustrated PRICE Tie. The Radio Experimenter's Hand- book t By M. B. SLEEPER Throughout the preparation of this book, one purpose was kept in mind— Answer the Practical Questions of the "Novice," of the "Beginner/' and the more advanced "Stu- dent." This book will help in the selection or construction of simple apparatus for the transmission and reception of radio tele- graph and telephone signala. In the chap- ters on radio receivers the simplest crystal, the simple audion, and the regenerative types are described in quite some detail. The question of antennas, both for trans- mitting snd receiving, are taken up. A good many helpful suggestions are given which will be of considerable aid to the experi- menter. 16 chaptera. Fully illustrated. PRICE $1.1 The A B C of Vacuum Tubes Used in Radio Reception By E. H, LEWIS Assoc. I. R. E, and Red Written particularly for the " knows nothing about radio." bat whs would like to gain an understanding of the elementary principles of operation of vac- uum tubes and various circuits in which they are used for the reception of radio- telegraph signals and radio- telephone me air and speech. Illustrated... Books on Electricity ArKksMtU et Itostrislty. By PRO*. T. CCONOB SLOANS. A srstrJoal tnatlss on •lestrleal osJsolsaons of sn kinds n- dnssd te a ssriss at rales, all at the stagiest Int sad Imvlrlnt only ordinary tiUhiaitlii. saah ra» UlasUslsd by ess or store practise! msMMSs elm detailed solution e» saota ens. This book is skaast asm the ass* sastal works published ss da snsooe of elootrtettr. oevsrtag as it dsas tas sMthsssttaj of electricity In s assnaer last am surest the sstsatlea of flaws was srs sot faadaar with alfsbralesl fonaalas. it* passe Near Bs- vtssd sad sWarted Bdltlar Pries. 1 1 J I By WTUJAal BAXTtB^j ■outer. This ' than; orerysno wee this lira edition. 0] By BDWABD TBXTBBT. prssossl directions tor ball dint a two Dynamo of lbs Bdlsss Ursa aapsbts of about afty amdea lamps of the 10-wstt s •iMin»i it rlres (firaetlorjs far baUduui « sterols enters soluble far raantns at shines. Tbs oondadlns chapter dSeeribee ■traction of s suapls bliililtsssu battery far ninnlns aloetrfs motors. »• pane. inuotrtUd with detail drawuus. Cloth. H. P. Dyaaaw BalMlai for Aawieers. or Mow t» Ote- ttnwt s Fifty Watt Dyaamo. By ABTRUB J. ffBD. A prseUoal trestus showing la detail the eotwtruetlon of s sutS dynamo or motor. Um entire auealne wort ■ which oon bo dooo on small foot laths. Dlmae- stoned worklot drawl nam srs siren for oaoh piosi of maehlno work, and each operation Is clearly dcsorlbod. Itds taaehlae. wbso used ss a dyosno. baa an output or fifty watts; wben used u 1 motor It wlD drive a small arm press or hues lt eso bo used to drlre s sewing maehlno oa any snd ill ordinary work. Tbo book ta Ulot- erstcd frith more than sixty eruinal eturarlnr* ■howl ox tbs actual ooostruotloo of tbs duTereot parts. Prist. SI.M ' ' Any of These Books Sena* Prwpauet •■ Racetiart of Price Th* tl Bowks for llfUes, ta Owe .r Diffwrwatf Ackaroess* address THE COLUMBIA PRINT ROOM 326, NO. 1493 BROADWAY, NEW YORK =

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15c. a Copy March 10 $6.00 a Year WOR D ILL US TRA TED WEEKL Y TOBOGGANING WITH RADIO MUSIC BY CORNELL STUDENTS (C. Wide World Photon The Ut«*t hnproveraent In the way of outdoor sports is the innovation recently brought out on the toboggan slide *t Beeba Lake. Ithaca. N. Y-. the hooM of Cornell University. They have Installed a complete radio rtcrmnc outfit with power aanfdmor and loud-spoahsr on one of tho toboggan sleds, and never want for music while enjoying the outdoor sport- Another good point is the fact that the orchestra cannot get cold and staff* **playing. At night the slide is flooded with light by means of large automobile headlight*, and It Is Chen that the students have their fun. iqitiz

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RADIO WORLD | JUST OFF THE PRESS I Vol. I. No. 2 THE RADIO CONSTRUCTOR Price 25c Mailed BUILD YOUR OWN SET This new edition of THE RADIO CONSTRUCTOR (Just off the press) Multratos and fully describes the most popular and efficient hook-ups. Full and complete instructions for the construction of Flewelling Reinartz Reflex Honeycomb And Many Other Tested Circuits Thla la tie book you have been waiting for. Got it today from your dealer, or It will bo mailed you postpaid on receipt of only 25c. Newman's Radio Plans also toll how to mako a crystal receiving set a super selective regenerative tuner, a loop aerial receiver, ohort wave regen- erative sot. medium wave tunor. radio frequency amplinor, etc.. sheets 17x22"— 25c. each. DEALERS! WRITE FOR QUANTITY PRICES! S. NEWMAN & CO., PublUrier. 74 Dey St., Dept. W., N«rw York City Inventor Sues Radio Corpora- tion for Alleged Infringement The Radio Corporation of America, a $25,000,000 company, which has many stations at various points in this country, has been made defendant in a suit brought in the United States District Court in Brooklyn by Walton Harrison, a lawyer and inventor, of 1974 Madison avenue, New York City. Mr. Harrison alleges that the company has infringed upon patents obtained by him in 1914 on a multiple send- ing antenna device. His suit is for an accounting of moneys made from the use of the device. Large sums are involved. In his affidavits Mr. Harrison states that multiple antennae are of vital importance to large sending stations. He alleges that his letters patent incorporate the basic prin- ciples on which the multiple antenna used by the company are designed. "The Laughing Lady" Broad- cast The first act of "The Laughing Lady," by Arthur Hopkins, was broadcast last week direct from the Longacre Theatre, New York City, with Ethel Barrymore starring. A description of the stage set- ting of this high English comedy was given by Bertha Brainard, who is known to radio audiences by her "Broadcasting Broadway" talks. Freshman Products, Especially Adaptable & New Flewelling "Super" Circuit VARIABLE RESISTANCE LEAK with .00025 mfd. Micon Condenser combined $1.00 without Condenser 75c. "MtCON" 1 TUHD MICA C0HKMW | c*r. mo* m. r. ■ MICON .006 Tested Micon Condenser . . . $1.00 At your dealers — otherwise i CHAS. FRESHMAN CO., Inc., m seventh Ave., New York ^l^&V'" "* Radio Perfection is attained only by the use of mechanically and scientifically perfect parts. Now, more than ever, when the mar- ket is flooded with inferior goods, one cannot be too careful in the selection of standard, trade-marked articles, and in purchasing from a reliable source. It is our aim to supply the highest standard radio specialties, thus insur- ing perfect results and satisfaction. Every article we sell is unconditionally guaranteed both by the manufacturer and this organization. FREDERICK H. PRUDEN Incorporated 993 Bergen Avenue Jersey City, N. J. Ajax Socket Rheostat A combination V-T Socket and Rheostat (or panel mounting. En- tirely eliminates separate leads be- tween socket and Rheostat and provides a panel-mounted socket without the use of additional brack- ets. Simplifies the installation and hook-up. Strongly constructed. Me- tal parts heavily nickel-plated. Type A-l, 5 Ohms— with knob and pointer, each JZ.OC. Type A-2, 5 Ohms— inch shaft without (C2-00 dial, list each ^ RADIO At Cut Prices Standard part* only m original packing. Sold on a "money- ^ *mkLbacK " bat i*. ■Reference "RADIO WORLD PHONES $8.00 Dictographs 8.00 Brandos 5.50 Murdook Phones 6.00 Muslo Phone* 1.M 12.00 Nathaniel Baldwin Type O, Doable. t.»5 6.00 Nathaniel Baldwin Type C. Simile. 4.M TUBES U. $00 **•*» U. V. 101 5-50 U. ▼. 101-A »•*• 1- K Tolt Special W. T. 501 Peanut *.M (Can be used on 8 dry cell* or « TOO. "A" battery) CABINETS Made in vat factory 7" I 10" T" I 18" 7" I 84" MISCELLANEOUS $20.00 Dictograph Loud Speaker $18.95 DUBATBX Permanent Crystal Deteetet 2.N $18.50 Homecharger ll.M WD-11 Adapter $1 50 Lightning Arrester, Indoor and Outdoor Typo •» 'Murdook Loud Speaker Horn with Phone.. t.tt $5.00 Acme Transformer. Radio and Audi* $.4* 5.50 — 180* Verloeoupler on Bakellte BUk Wound Wire 22i4 Tolt "B" Battery *> Ammeter for "B" Batteries «» $5.00 48-Plate Condenser <•»' 4.00 13-Plate Condenser '•»* 2 - Inch Bakellte Dials ■** 8-inch Bakellte Dials •** WD-12 Transformer for WD-11 Tube 4.85 $1.00 Freshman Vartabta Orid Leak and Condenser Combined " Genuine All-Ware Coupler $10.00 — 8000 Meter Coupler 4.t$ WHEN ORDERING BY MAIL Add Posture by the FoUowtaur PURCHASES Up to 91.00 ■** 91.01 to 91.00 " 1*c" 1.01 to 8.00 " *•«• 8.01 to 6.00 " 8.01 to 7.00 " *•«• 7.01 to 10.00 " **•" Money order or poroses! sneak accepted. RADIO STORES Dept. E. 2, 191 Fulton Street, N.Y.C NEW YORK'S GREATEST RADIO MAIL ORDER HOUSE Watch This, Little Ad of Big Specials »7.50 Murdock. 3000 Ohm Phones $}■»» 12.00 Genuine King Araplltone Horns 4.50 All Wave Couplers, 160 to 3000 avatars... 4.00 180 Degree Couplers, silk wound. j-« Couplers, 14 taps, pigtail connections. . . . . . 1.25 Bull Dog Plugs, $0.50; Doubls Phono Cords .•!» 23 Plate Condensers, $1.25:43 Plats I.St White's "Varlomont" Cement 25 Cash with Order — Allow Postage — Wholesale. Hetsil WHITE RADIO CO •New Veracity Publisher's Announcement on Page 7 — This Issue Digitized by Google

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VOLUME TWO OF RADIO WORLD [Entered as second-class matter, March 28, 1922, at the Post Office at New York, N. Y., under the Act of March 3, 1879] A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. VoL II, No. 24. Whole No. 50 March 10, 1923 15c per copy, $6.00 a year Takes Up Little Space, But Is Efficient Receiving Set By Louis S. Fielder NUMEROUS and varied are the models of miniature sets which have been made by various amateurs, but one that is especially complete, even to containing its own A and B batteries, was recently exhibited at the Permanent Radio Fair, New York City, by Frederic W. Proctor, a New York amateur. is only necessary to attach the antenna and ground in order to receive signals. The small block type B battery is used and flashlight cells are employed to heat the filament. While most of the miniature sets recently exhibited were slightly smaller than the present model, they all lacked the necessary batteries, and the fact that this particular set is (C. Photo News) Ingenious tube receiving set built by Frederic W. Proctor, • New York amateur. It is embodying everything necessary to make It complete in a most complete regenerative receiver, The set is a regenerative receiver, using fixed inductances with a small variable condenser to vary the tuning. As can be seen by reference to the illustration herewith, a peanut tube detector is used, the filament resistance being varied by means of a clip that is moved around the rheostat which is located directly inside the main inductance coil. The two coils are wound in staggered form and are in direct inductive relation to each other. The batteries are all located inside the small cabinet which makes this receiver complete in itself. It, therefore, absolutely complete even to that extent makes it stand in a class by itself. As to receiving qualities, much can be said. Of course, as it is a tube detector set, and regenerative, is extremely sensitive and performs remarkably well, considering the fact that it is so extremely small and compact. The builder of this set evidently had a very positive idea in mind before he constructed it, as the finished device shows careful planning of all details, such as the relation of the coils and also the best metho(j£5f j^j^^*^ Digitized by

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4 RADIO WORLD A Dry Cell Tube Socket— Cheap By Arthur G. Shirt FOR one reason or another tube sockets are unpopular instruments for home construction. Yet they can be made by the amateur, and well made, too. This is important, especially when so many amateurs are re- placing their six-volt V T's with 1^-volt WD-ll's, and are finding that they must either buy an adapter or a new tube socket. The WD-11 will not fit the regulation size socket, although the De Forest dry cell tube will, having been designed for that purpose. In other respects, these tubes are practically the same. PLKTC i o4i==© ru.. 5 OHIO Fig. 1. Assembly of a WD-11 socket as explained fat die accom- panying text. The exact dimensions are liven and should be strictly followed. A neat and practical socket will result. To aid those who want to construct a socket for their WD-ll's these plans are submitted. When finished, the socket will be neat and efficient. The contact fingers will make sure contact, and the bulb will be held as steady and upright as in any socket on the market. Fig. 1 shows the assembled instrument to be a square block of some insulating material, preferably hard rubber or bakelite, drilled with four holes suitably placed to receive the lugs of the tube. From each side of the block or base, a saw cut goes into one of the holes, so that each hole can be reached from the outside by a groove. This groove or saw cut should be about 54 of an inch deep. Four contact springs are cut out of spring brass and the upper half of each is bent in so that it will run in this groove and pro- trude into the hole about 1/16 inch. Binding posts are provided as shown, carefully marked for the grid, plate and filament terminals (as shown in Fig. 1) and then the socket is connected up for use. Perhaps the most troublesome item in the making of this tube socket will be in finding a square block of hard rubber suitable for the base. This problem may be solved by taking four or fire pieces of panel thickness and gluing or bolting them together so that they form one piece. In bolting, be careful to place the bolts so that they will not interfere with either the .-nr'net fingers or the binding posts. The proper size for the base is 2 inches by 2 inches by not less than % inch thick. It may be thicker if convenient, but owing to the length of the lugs on the WD-11 tube, the base may be no thinner than the size indicated. Any one who has examined a dry cell tube has probably noticed that the lugs coming from the bottom are not evenly placed and that one lug is larger than the other three. Be- cause of this unevenness, the holes must be laid out and drilled with the utmost precision. To amateurs who have dividers and rule the job may be easy enough, but even then look carefully to the detailed dimensions of Fig. 2. For the convenince of tnose who have no designing tools, a template for the holes is given full size in Fig. 3. Merelv lay this template down on the base, prick or punch the center-holes, and then drill as required. Another word of caution: Drill straight up and down! If you don't the tube will not seat itself on the base as it should, but will refuse to go all the way down. 1 HOCEfcMOE - t>*vw- 1 -+ — 'H 1 ■a--- 7T -to _L Fig. 2. Detail sketch for drilling the hard rubber plate and construc- tion of the spring. The ends of the spring should be rounded with a file, to permit easy insertion of the tube. Sizes of holes are very important and should be made exactly as shown. The saw cuts are easy. Saw straight across the top of the base, passing through the centers of two holes at once. Use a hack saw in preference to a wood saw. The groove should be cut about 34 inch deep. Cut the contact springs out of fairly heavy spring brass (Continued on next page) Digitized by 5Y Google

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RADIO WORLD 5 An Improved Single Circuit for Nite Owls By F. N. Hollingsworth A YOUNG amateur of Newfields N. H., Russell Sheehy by name, has copied 162 stations in 38 different states with his set, which is well located, with little or no local interference, besides Cuba, Canada, and Porto Rico, using one tube. While fundamentally the hook -up is of the common or garden variety of single circuit using a variocoupler, it has several refinements which have given him the remarkable results mentioned. It has added a three-piate vernier con- denser shunted across the rotor winding, which gives a change in classification. He uses a potentiometer for grid control, as well as one for plate control. The stator is wound on a four-inch bakelite tube and has 35 turns of No. 24 D. C. C. magnet wire, without tape. For the tickler he has the same number of turns, with the same size wire, wound on a 3j4-inch diameter support. This tickler rotates on one end of the rotor tube. Following the diagram given herewith, the antenna con- denser, CI, is the usual .0005 vernier variable. C2 is .0005 for a UV-200 tube and C3 is .005. C4 is a three-plate vernier. High grade condensers must be used in any set, and the one shown in the diagram is no exception. Potentiometer R2 is of the 200-ohm type and R3 is one of 400 ohms. R4 is the usual 6-ohm vernier rheostat, the former being used for controlling the kind and amount of potential on the grid and the latter for providing accurate adjustments of voltage as required of UV-200 and detector (Continued from preceding page) and provide four 1J4 inches by J/£ inch in size. Cut as shown in Fig. 2 and bend the fingers at right angles. Drill for the binding posts and also put a slot in the other end for the tension screw. These contact springs go on flat against the sides of the base with the fingers going in the grooves to the tube holes. The binding posts hold them rigid at one end, while tension screws are placed in the slots at the other end. Now when the tube is pushed in the socket, the lugs will press outward on the contact fingers, which will resist the pressure according to how springy the brass is and how A. A; Fig. 3. Template for drilling holes in bate of tube socket. If you cut this out and paste it on die hard rubber there need be no fear of coins; wrong, as It is exactly right and will save measuring. tightly the tension screws are set up. Practice with a socket of this design has shown that the tension screws need never be tight. Now comes the most important part of the job, namely, to mark the binding posts so that the proper connections can be made. The extra-large lug on the WD- 11 is the plate terminal, so the binding post which connects with the 3/16-inch hole should be marked PLATE. The lug oppo- site is the grid, so mark that binding post GRID. The other two, of course, are the filament terminals, which should be marked, too, in order to avoid mistakes. tubes. Grid leak Rl will vary between one-half and two megohms, depending upon the tube in use. Tuning is quite simple in this circuit, the carrier wave being picked up by adjustment of the condenser, CI, which should be a vernier type for correct results. Then the con- denser C4 (a three-plate vernier) should be varied until signals have cleared out. The operator can do this by variations in coupling between stator and rotor until he finds the best combination. Movement of the rheostat handle R2 will serve to vary volume and quality of signals received. R3 will make the detector tube more sensitive Diagram of circuit described by Mr. HoHingsworth. The two potentiometers give stability to the circuit and make tuning-out of nearby stations easier. at its correct value, which is easily found by adjusting the knob R4. The filament rheostat should have a vernier adjustment for best results. While those who may set up this particular circuit may not be able to duplicate exactly the results of the originator, owing to difference in location, condition of atmosphere, interference, etc., they will be able to get satisfactory results if they use care in connecting up and in adjusting afterward. Careful adjustment is pne of the biggest factors in securing satisfactory reception in any set. The owner of this set has totaled over 112,000 miles, using the radio "golf" method of computation. An Explanation to Our Readers Perhaps you are among those RADIO WORLD readers who have not been able to get copies of this publication through your newsdealer a day or two after the day of publication, owing to the fact that there has been such an unusual and increased demand for RADIO WORLD of late. We have increased the edition of this week's issue very materially and you should have no difficulty in getting copies through your regular newsdealer. If your dealer sells out before you go to bim, will you favor us by sending his name and address on a postal card? We will endeavor to see that he is supplied. We also suggest that you become a regular sub- scriber so that you will not miss any copies. Our sub- scription rates are $6.00 one year (fifty-two numbers). $3.00 six months, $1.50 three months. You can subscribe direct or through your newsdealer, who, by the way, should send your order to us immediately, less his com- mission. Digitized by Google

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6 RADIO WORLD "American Interests May Rule World Radio" — Admiral Ziegermeier, Chief of Naval Communications By Carl H. Eutman THE Radio Corporation of America and the U. S. Naval Radio Chain may eventually control the radio of the world. This is the opinion of Rear-Admiral H. J. Ziegermeier, Chief of Naval Communications. The impression that the Naval Communication Service might be trying to compete with or control commercial radio traffic is entirely erroneous. The Navy strives to maintain efficient and uninterrupted communication between all units of the U. S. Fleet, and to that end maintains many land stations. From its stations on both sea and land com- mercial messages are handled when other facilities are not available. Instead of competing with commercial stations, the navy charges a little more for handling traffic, except in the Pa- cific, and has closed a number of stations recently where other facilities existed. Close co-operation between the naval and American commercial radio interests have existed for several years. In this connection, Admiral Ziegermeier recently stated that it was due to representations of naval officers that the Radio Corporation of America was organized in October, 1919, to take over commercial stations and traffic handled by the navy during the World War. Admiral Ziegermeier reviewed briefly the activities of the commercial companies in this country, and among them named the Radio Corpora- tion of America, the Tropical Radio Company, Federal Telegraph Company, and Independent Wireless Company. "Of these the Radio Corporation of America have the largest facilities," he said. "They have direct connection to England, Sweden, Norway, Germany and France. They are building a station in Poland which will soon be in oper- ation, and the Buenos Ayres station will be in commission this summer. This company has valuable franchises in South America. In the Pacific it has the Honolulu station for its Japanese connection. A company has been formed by the Radio Corporation and the Federal Telegraph Com- pany for operation in China. China has granted the neces- sary rights to erect and operate four stations and this work is now under way. "This company, with its connections and the naval radio chain, bids fair to control the radio of the world, as Eng- land now controls the cables," Admiral Ziegermeier claims. "The Federal Telegraph Company," he said, "operated a point-to-point service on the Pacific Coast at Los An- geles, San Francisco, Portland and Seattle, and also han- dled some ship-to-shore work. Through its affiliation with the Radio Corporation of America, it will eventually have connections in China." The Admiral explained that, al- though the Federal Company has the necessary grant from the Chinese Government, there have been some delays in getting started, due to the desire of two other nations to block American interests. His latest information, he said, was that these obstacles had been overcome, and that the construction of the stations would begin immediately. Admiral Zeigermeier said the Tropical Radio Company was connected with the United Fruit Company and had stations in Central America, where it was extending its facilities. He stated that the Tropical Company has sta- tions in Boston, New Orleans, and Miami, and is anxious to locate a station in Panama. The Independent Wireless Company handles mostly ship-to-shore traffic, he added. The Navy and Pacific Traffic In October, 1922, the Admiral said he attended the Pan- Pacific Commercial Conference at Honolulu, where there were present 110 delegates representing 16 countries. One of the most important subjects considered by the confer- ence, Admiral Ziegermeier said, was "Communications," especially with reference to expanding the already existing government radio stations to the extension of press service. If other countries on the Pacific would be willing to receive our press at a corresponding low rate, all difficulties would be removed, he explained. He said that a resolution adopted by the conference on the subject of communications urged that the governments of the countries use their radio facilities in cooperation with each other or with other agencies, to provide means of intercommunication for the public, wherever such serv- ices could not be obtained through private agencies, the chief objects being to secure the transmission of commer- cial messages at the usual commercial rates and the trans- mission of news messages promptly and at the low rates. In outlining the navy's service to the public, he said that the navy may use its radio stations for press and commer- cial traffic under certain restrictions. Generally speaking, he said, the navy handled commercial messages at any of its stations at rates not less than those charged by commer- cial companies for like messages and for like service. This service ceases, however, when the navy is notified by the Secretary of Commerce that a commercial company is able to fulfil the requirements. It was thus shown that the Naval Communication Service is never a competitor with commercial companies. In the Pacific, however, the -navy is permitted, by law, to handle press to practically any locality at any rate, pro- vided only that one end of the transaction is connected with American interests to the extent at least of being any news- paper published in, the United States or a newspaper pub- lished by its citizens. This authority on both press and commercial traffic, it was pointed out, expires Tune 30, 1925. To-day, practically all news service in the Pacific is handled by the Naval Communication Service, the commer- cial rates being prohibitive for any satisfactory service. The Associated Press sends on an average daily about 1,000 words from San Francisco to Honolulu, and about 800 words to Manila. This service is said to be most satisfac- tory to the press, and Admiral Ziegermeier said he had heard many complimentary expressions about it. The com- mercial companies have as much as they can do without handling press messages, he added. The navy press rate to Honolulu is three cents a word and six cents a word to Manila. To explain the situation, it was shown that the commercial radio rate from San Francisco to Japan is 72 cents a word; for press, 27 cents a word (subject to delay) and $2.16 a word for "urgent." The cable rates between similar points are 96 cents, 32 cents and $2.88, respectively. As privately owned radio stations are not permitted to op- erate in the Philippines, the'U. S. Navy must be depended upon for all radio communication with these islands, he said. Digitized by Google

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RADIO WORLD 7 Receiver Operates Under New Principle Invention of Professor i m • 4 > ii 'r • ■-' (C. Kadtl & Herbert) The new Hazeltine circuit receiver. Five tubes are used and the circuit la incapable of regeneration or oscillating, which is the cause of much inter- ference in the present-day receivers, especially where many are located in a small district, such as New York. ONE of the most recent improvement in the field of receiving instruments was recently made by Professor L. A. Hazeltine, of Stevens Institute, Hoboken, N. J. The receiver embodies an entirely new principle in reception and cannot radiate energy. This radiation of energy is one of the great drawbacks of the heterodyne and regenerative sets of today. Due to this fact, and also that it is an extremely powerful receiver capable of receiving marvelous distances, a popular future is predicted for it by its inventor. In a test of the receiver a few feet of bare wire was thrown across the floor, serving as an antenna, and reception of long distance was possible. As can be seen by the illustration it embodies five tubes, in connection with three couplers or inductances, and in this form is different from the regular sets. As many people know, England forbids the use of regenerative circuits, because of their habit of re-radiat- ing signals and {hereby causing disturbance to sets in the vicinity. It was proved that a regenerative set embodying three tubes with sufficient plate current to operate it efficiently, could cause, through re-radiating signals, disturbance in receivers over a quarter of a mile away. This is especially noticeable in the more crowded districts such as New York, when there are many people listening in. The different sets can ac- tually be used as small distance transmitters, and the writer has actually carried on conversation over a dis- tance of over 650 feet air-Jine with a party having another regenerative set. This will be absolutely prevented by the use of the new Hazeltine circuit, which, as said before, is incapable of re-radiation, and is at the same time a sensitive and flexible long distance receiver. As it does not need an outside antenna to operate efficiently, especially where local work up to 100 miles is desired, it will solve a lot of the problems that are so prevalent today in connec- tion with the question, "Where can I put my antenna?" Publisher's Announcement RADIO WORLD, THE OLDEST RADIO WEEKLY, WILL CELEBRATE ITS THIRD VOLUME BY ISSUING A SPECIAL ANNIVERSARY NUMBER DATED MARCH 31, PUBLISHED MARCH 28; LAST PAGE OF RED FORM GOES TO PRESS MARCH 19. LAST PAGES OF BLACK FORMS CLOSE MARCH 22. Regular advertising rates for this issue as follows: One page: One time— $150.00. Half, Quarter, Third and Two-thirds pages at pro- portionate rates. One inch, one time — $5.00. Per agate line, $0.40. On four consecutive issues, 10% discount. On thirteen consecutive issues, 15% discount. Cover and preferred-position rates made known on application. No extra charge for advertisements in two colors if copy reaches this office on or before March 19. This issue will be specially advertised, have an un- usually large distribution and will give splendid adver- tising results to everybody represented. RADIO WORLD WAS THE FIRST RADIO WEEK- LY IN THE FIELD. IT HAS BEEN THE LEADER IN ITS CLASS FROM THE START. IT INTENDS TO REMAIN SO. If you want big value in this important issue of RADIO WORLD, be sure to get in touch immediately with our advertising department. RADIO WORLD, 1493 Broadway, New York City. ONE REASON WHY RADIO WORLD MADE A HIT FROM THE START AND EVERY WEEK IS INCREASING ITS HOLD ON THE RADIO PUBLIC: BECAUSE IT GIVES THE NEWS AND DEVELOP- MENTS OF SCIENCE AND BUSINESS OF RADIO EVERY WEEK AND FROM TWO TO SIX WEEKS EARLIER THAN THE MONTHLY RADIO PUBLI- CATIONS. Digitized by Google

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RADIO WORLD How to Bank-Wind a Coil By Arthur S. Gordon AS far as telling at a glance how bank-winding is done, the average commercial bank-wound coil is a deep mystery. Wires tuck under eachfther and then disappear entirely. Any attempt short of wrecking a coil fails to uncover the method of construction, and so the radio amateur who thought he could figure it out by look- ing at the coil, leaves the radio store vowing that as far as he is concerned, the secret of how to wind coils in two, three or four layers will remain untold. The idea of intensified inductance is familiar to all. The ordinary single layer coil, which is easiest to wind and therefore the most popular, is ideal for short wave lengths, but for long wave lengths the size of the coil becomes pror hibitive. Coils eight or nine inches in diameter and stand- ing four and five feet high are no longer in favor with radio amateurs, although a few of these monstrosities for- merly graced the shack of the long-wave radio enthusiast. Gradually, new forms of winding were employed which COIV, IS TO OS VWN6 k- PA/\rAOT<ELL OR r^OVXEtV-TOWEu" Fig. 1. A mandrel or winding-jig recommended (or winding the bank- wound coils described in the text. It is almost impossible to wind colls by hand without a device of this sort. not only cut down the size of the coil but actually increased the inductive effect to a maximum. One of these forms is the double, triple, or quadruple-layer coil which, because of the manner in which it is wound, is commonly known as the bank-wound coil. Many amateurs wonder why it is not feasible to wind a number of layers of wire, one on top of the other, thus making a compact long-wave tuner. In such a winding, the effect known as distributed capacity is at a maximum. Distributed capacity may be defined as that loose and un- desirable element in a radio receiver over which the oper- ator has no control. When it is present to any degree at all, the coil or circuit will have a natural period or wave length of its own, and will perform more satisfactorily on one wave length than on any other. Tuning is rendered difficult if not impossible, and sometimes the other instru- ments in the circuit are prevented from functioning. In order to overcome this effect there have been evolved many types of winding, and among them is the bank-wound coil. It is not an easv winding. Without some arrangement such as shown in rig. 1, and a supply of collodion or coil cement, it is practically impossible. Yet when the amateur poes about it with care, first mastering the method as de- scribed in this article, bank-winding becomes easy. Once the amateur completes a finished coil, he will become official bank-winder for the whole neighborhod. The home-made form needed consists of a wooden roller just the size of the inside diameter of the cardboard tube on which the coil is going to be wound. A three and one- half inch tube is about the size recommended. This wooden roller is mounted on a wooden bracket much after the fashion of a roller towel arrangement, the important part of the construction being that the roller can be taken from the bracket at will. When the bracket is screwed down to a bench or table, a leather strap is fastened to the table just behind it, and passed over the roller to a foot pedal hinged to the floor or wall. This pedal is the brake, and when winding, a slight foot pressure will hold the coil rigid so that the turns may be wound very tightly. This mandrel— another name for the device — need not be anything elab- orate ; the roughest construction will do the work. The cardboard tube on which the winding is to be placed is tacked to the roller. Place the tacks along the end of the tube so that they can be withdrawn after the winding is completed. Supply yourself with either collodion or cement so that you can make the turns self-supporting as you go along. Then begin the winding. Bank-wound coils may be double, triple or quadruple layer. A double-banked coil is easier to wind than a triple, while a triple is easier than a quadruple. The same prin- ciple, however, holds good for all, so in the instructions which follow for the winding of a three-layer coil the amateur will find a method for winding two and four-layer tuners. The first step in winding a three-layer, bank-wound coil is to complete what are known as the "anchor" turns. They are six full turns wound in pyramid fashion on a base of three. In studying Fig. 2, in which four progressive steps are specified, give your attention to each step in turn, mas- tering the detail in one before passing to the next. Close your eyes and imagine yourself winding a tube on a form suggested in the preceding paragraphs. Get the idea of the winding firmly in your mind, and then, as the process is explained in detail in the next paragraph, follow each step through once again. In detail, the procedure is as follows: Bring the wire ( No. 20 or 22 S. C. C. copper wire) up from the inside of the coil, or from a binding post mounted on the coil and make three complete revolutions, laying down three turns as shown in "A" of Fig. 2. Put the brake on the winding device, and holding the free end of the wire with one hand, apply a solution of collodion or coil cement with the right hand. For this operation of cementing the three rums together, shellac will not do. In the first place, shellac is going out of favor with radio experts on account of its tendency to increase distributed capacity, and in the second place it is not of sufficient body to hold these first three turns together as firmly as they should be held. At the end of the third turn, make a sharp angle to the left and wind the next turn on top and in the groove be- tween turns Nos. 1 and 2. See "B," Fig. 2. Turn No. 5 is wound in between Nos. 2 and 3 as shown in "C," while the last turn of the "anchor" goes in the remaining groove, which is on top of and between Nos. 4 and 5. The last sketch in Fig. 2 shows the anchor turns complete. At this point apply collodion once more. Now, when the anchor pyramid is complete and the collodion has hardened, make a sharp inward angle as though you were going to pierce the tube with the wire. Instead, straighten out with (Continued on next page) Digitized by Google

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RADIO WORLD 9 A Code of Ethics for Radio Fans By O. G. De fVitt ' TWO simple yet important rules constitute what has been termed a "code of ethics for radio fans." In operating our radio receiver so as to get the maxi- mum of enjoyment out of it, we should also think of the other fellow, and the two rules formulated by L. W. Chubb, a well-known radio engineer, show that this unselfishness is not only practical but that it really reacts to our own good. Surrounding all of the high-powered broadcasting sta- tions is a broad belt of radio receivers, most of them of the inexpensive crystal type. The first rule of behavior con- cerns the operation of crystal sets. Always de-tune them when they are not in use. It seems that when a radio re- ceiving set is tuned to the wave length of a second station, the coils of that set absorb some of the radio energy, re- gardless of whether that energy is rectified by the detector and sent to the phones to be enjoyed by the listener. In other words, an idle crystal set, if in tune, will take away from the sum total of a sending station's energy and thus rob somebody else who is farther away from the trans- mitter. To avoid offending in this respect, always throw your dials to the zero position when you sign off your crystal set for the night. It is not necessary to throw your de- tector out of adjustment. With this rule, the owners of vacuum tube outfits do not need to concern themselves, be- cause when they shut off their tubes, their aerial and coils are harmless. There is, however, a rule about vacuum tube operation- that should be taken to heart by every tube owner. Do not hunt for stations with your tubes oscillating. To do so is to annoy the listener-in at a nearby set, who can hear a shrill whistle emanating from your set as you go up and down the scale in search of carrier wave whistles. One "peanut stand whistle," as this interference is called, is not bothersome, but when a thousand neighboring stations be- gin hunting with their cut-outs open, the resulting inter- ference is the most persistent and annoying characteristic of present-day radio. When your tube set is operating at excessive regenera- tion, it is in reality a miniature transmitting set. It sends out at once everything that it brings in. There is, of course, an appreciable lag between the original signal going on its way and the re-transmitted signal from your receiver. When another receiver is reached, it not only records the reception of the original music but it also piles on top of that music, the reproduction of it sent out by your station. This is what causes the gurgling and distorted music and speech often received over the radiophone. You are frequently annoyed by these apparent defects in radio. Why not resolve now to help the situation by tuning-in with your set just on the verge of oscillation, and not in a howling state of excessive regeneration? If we want the quality of broadcasting programs to improve, we must also improve the quality of broadcasting reception, and there is no better way for a radio fan to do this than to observe one or both of the rules given above.' {Continued from preceding page) another sharp angle and continue the winding, laying turn No. 7 alongside No. 3. As turn No. 8 comes around it goes on top of No. 7 and runs next to No. 5. Turn No. 9 is on top of No. 8 and next to turn No. 6. Turn No. 10 comes down to the first layer again, and the succeeding turns are wound against the inclined bank of the three preceding turns, and so on until the required number have been taps — about every twenty-four turns — take them from the first layer always, so that the two other layers can cross over the twist and help to hold it in place. Be liberal with the coil cement and above all things — take your time! Four and five-layer coils are wound in the same way as three-layer, with the exception that four and five layers", respectively, are placed at the base of the anchor winding. Bank-winding is not used in short wave tuners, but in 7 \ V — y- tT~'_ 4 Fig. 2. Progressive steps in winding a bank-wound coil. Care should be taken .that the tensioa is even so that the top turns will not slip. placed on the coil. Every third turn after the sixth appears on the top layer, and the only difference noted between the appearance of a bank-wound and a single layer coil is the spiral path indicating where the top turns, one after the other, have been turned down to make the next turn on the first layer. Don't make all the turn-downs in the same place, but drop back about of an inch each time. In taking out loading coils or in long wave instruments, nothing is quite so effective. On a cardboard tube no larger than that used for an ordinary tuner operating on 360 and 400 meters, enough turns can be bank-wound to bring in everything that sends on less than 3,400 meters — and that's pretty nearly everything. Bank-wound coils are intensified in- ductance, and not only that, but they keep down to a mini- mum that deadening effect known as distributed capacity. Digitized by Google

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RADIO WORLD A Long Distance Three Tube Set By H. Spencer Lewis THE most important tuning element in this strange set is the combination coil containing the primary, secondary and regenerative windings. Contrary to popular belief the induction set up by a primary winding is not best absorbed by a secondary winding inside the primary, but on a plane with it and outside of it. This gives a maximum induction in one sense and a maximum of selection, permitting extremely accurate tuning. Hence this tuning coil should be made of a cardboard or fibe tube six or seven inches long and four inches in diameter. At one end there should be twenty turns of number eighteen D. C. C. wire. S. C. C. wire will not do. More turns can be used for this primary winding if higher wave lengths are desired, but 20 turns will take care of wave lengths up to about 700 meters. By putting the primary condenser in parallel with these twenty turns the wave length can be increased. If more turns are used, taps should be put on every second tap above and beginning with the eighteenth. Note that the last turn, toward the center of the tube, must have the connection from the ground. tu modulate the whistling, while acting at the same time as a tuning device, for with this condenser alone one can tune in or out a number of stations on any given wave length without disturbing the other condensers once they are set And stations selected in this wise would not be located if this condenser did not do this little trick. The elements in the set are as follows : 1. Fixed condenser, .00025. 2. Variable condenser, 43 plates. 3. Variable condenser, 43 plates with one vernier of 3 plates. Fixed condenser of .00025 mfd. Fixed condenser of .00025 mfd. Variable condenser 43 plates. Fixed condenser of about .0005 or .001 mfd. Transformers of any standard make, at right angles, are used. If possible use regular 4 to 1 transformer for first stage and 7 to 1 for second stage or a R. C. A. audio trans- former. The rheostats for detector and first amplifying tube should be Bradleystats, because they permit extreme 4. 5. 6. 7. 20 Turns p Fig. 1. Schematic diagram of the set described by H. Spencer Lewis in the accompanying article. The filament leads for the second and third tubes are left open to show that each of the tubes Is supplied from separate batteries. This Is done to prevent any back-coupling through the battery leads. After this primary winding is completed, leave a space of half an inch and wind 35 turns of the same wire. This forms the secondary winding. It should be wound in the same direction as the primary winding, and both windings are determined by the winding of the rotor within the tube, for the rotor must be wound in the same direction as the primary and secondary. The rotor should have about 35 or more turns of 22 S. C. or D. S. wire. The shaft for this rotor should come in the half-inch space between the primary and secondary windings, and the ball should fit snugly in the tube. Therefore, before starting to wind the tube get your ball and either shave down the ball to fit your tube or make the tube slightly smaller to fit the ball. In making the secondary connec- tions be sure that the first turn of the 35 secondary turns, the one nearest the rotor, goes to the grid leak. The con- nections to the rotor from plate and transformer will have to be determined by listening for the regeneration and oscillations. If wrongly connected there will be few or no oscillations. The rotor acts as a tickler despite the fact that it is located between primary and secondary and you will soon note that it seems to be regenerating radio fre- quency oscillations in a manner peculiar to itself. The other odd feature of this hook-up is the condenser shown at No. 6. This I call a modulating condenser, for it acts as a vernier on the tickler regeneration and also helps lowering of current, gradual increase, fine adjustments, and are absolutely noiseless, which is exceedingly im- portant in picking out weak distant stations before bring- ing them up to maximum loudness. The potentiometer shown at No. 8 should also be one which is not in steps, but graduated like the Bradley, for stations can be tuned in or out on this alone, sometimes a slight increase bringing a change of many stations. The detector tube should be preferably an A. P. or Moorehead, but for those who are out of luck in this regard, some Radiotrons or Cunningham tubes are critical and oscillate at a low point and these are very fine. Any good tube, even the four-volt Myers tube will also work well. The first amplifying tube will be almost as critical as the detector tube. In finding the proper plate voltage on the detector tube, do so with the potentiometer set in its middle or neutral point so as to leave a range for increase or decrease. The more distant the station being tuned-in, the less plate potential and filament current will be needed and in some cases loudness is reached by turning down the amplifying tubes, even turning the last one down to its lowest point and at other times by turning the first one way down and the second one on full. In operating observe these points : First, find where your (Continued on next page) Digitized by Google

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RADIO WORLD 11 (Continued from preceding pane) detector oscillates by adjusting the primary condenser, rotor and secondary condenser along with the detector, rheostat and potentiometer. Once the oscillations are noted, keep your adjustments confined to that small field and try to soften the oscillations, remembering that you may be generating QRM for many others in your neighborhood. Once you locate some broadcasting station, either 360 or 400 wave length, you will find that all other stations are within a quarter-inch on all your condensers. But for long distance stations you will have to slightly increase the posi- tion of your rotor. In between the low soft whistles you w ill find the distant stations by adjusting the verniers on vour secondary and primary condensers. Then use the modulating condenser and rheostats to clear away all TO nrmSfiyyer / There Aro Gonntctfont fob* Reverse* Unf-if tfieStt*- ^Oscillates 'to P/crte Putting Themselves on Record Fit. Z. Diagram at ths coupbr to am used with circuit akown in Fig 1. Th« two cads ara wound on the same tub*. Tbe coopttng is nwvabls. Rar*n«rmtion ii obtained tJirourh varying tbs tickler. whistling and add loudness. It will take probably several hours to become acquainted with the tuning of this set, but once you have found the critical points on each dial or knob, you will be able to go back any time and pick out any station. I have picked out seven distant stations on 360 meters by moving the vernier of the secondary con- denser within a space of half an inch only. erators licensed totaled 12,113. Commercial licenses issued increased alxait SO per cent, and amateurs' licences were nearly eight times as many. In 1922 there were i^ued 8,920 amateur licenses, and in 1913 only 1.841. As a'l of these o]>erators' licenses are issued for two-year periods there are practically doulilc this number of amateur stations in operation. Berlin, Germany, Picks Up WOR. Newark. N. J. MUSIC transmitted from the United States was heard in Germany for the first time on February 24, according to a press dispatch from Lichterfelde. a suburb of Berlin. The experimental wireless station at Seehof, at 6 a. m., picked up the voice of Miss Edith Bennett sinking in the department store of J. Rambergcr & Co., Newark, N\ J., station WOR. The vocal and instrumental tones were perfectly audible. The transmission is re- Cirdcd as remarkable since the broadcast- ing station operated on a 4O0-meter wave lentrth. the same as is commonly used i-<r nearby American lisiencrs. Kisht htifh i acuum amplifiers were u-ed in receiving. I. tit only ordinary antenna, eight meters Ivgh. Digitized by Google

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12 RADIO WORLD Methods of Measuring Properties of Electron Tubes Apparatus Used by The Bureau of Standards IN papers dealing with the operation of electrical cir- cuits which use electron tubes, as well as in the design of radio equipment using electron tubes, certain prop- erties of the tube appear to be of much importance. This article describes apparatus used at the Bureau of Standards, Department of Commerce, Washington, for measuring some of these properties. Those included are: I. Combination alternating-current bridge for measure- ment of ( 1 ) Internal input resistance. (2) Internal output resistance. (3) f Amplification coefficient. II. Arrangement for measurement of I (1) Direct-current characteristics. (2) Power output of generator tubes. III. Measurement of detection factor, There are other important factors which are not covered This bridge is an alternating-current bridge which by simple switching arrangements may be used to measure internal input resistance, internal output resistance, and amplification coefficient under any condition of grid volt- age, plate voltage and filament current. The principle involved in each of these measurements can be seen by reference to Fig. 1. In each case the contact on the slick wire is varied until there is no sound in the telephone receivers. When this condition is satisfied the value of the factor desired is given by the relation indicated. The complete circuit arrangements is given in Fig. 2 in which 1 and 2 are SPDT switches. 3 is a SPST switch. 4, 5, 6, 7, 8 and 15 are terminals to which auxiliary apparatus is connected as indicated. 9 — Filament ameter. r I L 1 — wwwvw — a — ■A.C.SUPPL.Y • r— — vvW/vvv — I vwwwvv — i — wvWvw- */VW^VvV — ■ A. C. SUPPLY G F1GJJ4 INTWNAL INPUT RESISTANCE, (fjs ) WHEN THEJtC 13 3UJEMCE. IN THE, PHONE*, T FIG l.H.) INTERNAL OUTPUT RESISTANCE (T«) WHCM THEItt. » SILENCE. IN THE. PHONES T AC -SUP PLY — F10.I.IC) AMPLIFICATION COEFFICIENT^ WHtNTHlKEI* SILENCE. IK THE PHONES. T by this series of articles. Some of the more important of these are, inter-electrode capacities, mutual conductance, and detection factors defined differently from the one included in an article to appear later. The methods of measurement used have been described by several writers* on the subject and this paper is in- tended to give convenient circuit arrangements that may be used for the rapid determination of the various properties with the values of the circuit constants that have been found most convenient. /. Combination Alternating-Current Bridge for the Measurement of Internal Input Resistance, Internal Output Resistance, and Amplification Coefficient. •J. M. Miller, Proc. I.R.E., June. 1918. H. J. van der Bill, "The Taermonic Vacuum Tube," Chap. VII. J. H. Morecroft, "Principles of Radio Communication, Chap. VI. 10 — Grid voltmeter. 1 1 — Standard receiving tube socket. 12 — Terminals for connecting non-standard tubes. 13 — Slide wire. 14 — Two-stage audio-frequency amplifier. G — Ground terminal. R — Standard resistance box, variable from 0-100,000 ohms. Rj — Filament rheostat. R2 — Grid voltage divider. R3— Rheostat 0-10,000 ohms. R,— Rheostat 0-1,000 ohms. R6 — Voltage divider 0-1,000 ohms. S — Reversing switch by means pf which the grid may be made either positive or negative with respect to (Continued on next page) Digitized by Google

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RADIO WORLD 13 (Continued from preceding Page) the negative side of the filament, as indicated by the + and — signs on the switch. (1) Measurement of internal input resistance (rg) Switches: 1. Closed at a. 2. Closed at c. 3. Open. When the switches are as indicated the circuit may be reduced to the simplified diagram, Fig. la. The tube to be measured is placed in the socket 11 or connected to the terminals G, F — , F+, P shown at 12 in Fig. 2. A filament battery is connected to the terminals at 4 and the current indicated by the ammeter (9), adjusted by the rheostat Rx to the desired value. Between the two of the three terminals at 8 marked "Plate Bat." is connected a battery which must have the exact plate voltage desired as no means is provided for varying this voltage except by the addition of series cells. A voltage divider canot be used because of the exjra resistance inserted in the plate circuit. A battery giving the voltage desired for the grid is con- nected to terminals 5. All the batteries must be placed near the apparatus and connected with as short leads as possible so as to minimize induction from any a. c. source. The audio-frequency generator used may be either an alternating-current machine or an electron tube generating set. It is desirable that it be capable of being varied over the audible range, although this is not necessary. Best settings may be obtained with frequencies of 1,000 to 1,500 cycles per second. A high-resistance direct-current voltmeter having a re- sistance of 100,000 ohms or more, is connected to the terminals at 8 marked "Plate VM." The telephone re- ceivers used for indicating a null point are connected to the second stage of the amplifier unless there is too much noise due to induction to make an accurate setting, in which case measurements may be made with less accuracy using only one stage of amplification. The grid voltage, indicated by the voltmeter (10), is adjusted by the voltage divider R2 to the desired operating point, R is set at 100,000 ohms and the slide wire adjusted for a minimum sound in the phones. Further adjustments are made by changing the position of the slider of R4 until the best minimum is obtained, then readjusting the slide wire, repeating this operation until almost a complete silence is obtained for the minimum. It will be noticed that R4 is a resistance across the input leads, with a variable midpoint at which the ground is connected. It is possible to compensate for capacity-to-ground effects almost entirely by changing the position of the ground in R4. When there is complete silence in the phones T then ri rg== R. r, If it is desired to measure the alternating current voltage applied to the tube during a measurement a low-voltage a. c. voltmeter (for example, a high resistance thermo- element and micro-ammeter calibrated in volts) may be connected across the input terminals (7, Fig. 2). It is evident that the alternating current grid voltage is equal to the voltage drop across rx (see Fig. la) when silence is obtained in the phones T. Then the impressed voltage _ rtE rt + r, + R, where E is the voltage impressed on the bridge and meas- ured by the voltmeter connected across the input terminals. If the input resistance of the tube is high (over 10" ohms) difficulty- will be experienced in making accurate settings and accuracy of the bridge decreases. (2) Measurement of internal output resistance (rp) Switches 1. Closed at b. 2. Closed at c. 3. Open. When the switches are as indicated the circuit arrange- ment reduces to that of Fig. 1 (b). Resistance R is set at about 50,000 ohms and the point C on the slide wire adjusted until a minimum is obtained. R4 is adjusted along with the slide wire until complete silence is obtained in the telephone receivers. If the ratio — is too large or too small for accuracy then R is changed to bring the setting near the middle of the slide wire. Read- ings are taken with two or more values of R and the results averaged. With silence in the phones rp = — R. This measurement includes the resistance of the plate battery which for new cells can be neglected in comparison with the resistance of the tube. (3) Measurement of the amplification constant (/u) Switches 1. Open. 2. Closed at d. 3. Closed. This arrangement of switches reduces the circuit to that of Fig. 1 (c). as v r* r. 4 j5 © r 5 no.e a c e 13 if •«««. » — . \j I — i » j winjnca. • W I , COMBINATION BA1DOL FDR MEASWUMCNT Of INPUT ItUISTANCt., evmrr ruistancc ano amplification cooneimT G, The slide wire and R4 are adjusted for minimum sound as described above and when silence is obtained rt /u = - In all the preceding measurements, and especially in the measurement of rg, care should be taken to keep the alter- nating current input as low as possible consistent with accurate setting of the slide wire. When adjusting for minimum sound in measuring /u, the importance of adjusting R4 closely is not marked, as it does not affect the slide wire setting appreciably, but in all the other measurements, changes in R4 affect both the amount of sound at the minimum, and the setting of the slide wire, so R4 must be adjusted carefully to obtain a minimum as close to silence as possible. This is best done by moving the slider of R4 back and forth over the mini- mum point and at the same time turning the slide wire (13) slowly in one direction until the nearest to complete silence is obtained when R4 passes its minimum point R4 is left at this point and the final adjustment made on the slide wire. Tubes should be left burning for two to five minutes before making measurements to allow them to come to a condition of stability. (While this article is complete in itself, it will be followed by others on the sane subject, and equally important.) Digitized by Google

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14 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coining Into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Clearly Explained By Lynn Brooks TT JT HAT are the advantages of using a crystal t/m/ detector in connection with a reflex set? r r When using a reflex circuit a crystal detector is advantageous because it is the quietest detector known, not having troublesome tube noises and also being the most distortionless. A crystal, while not quite as sensitive as a tube, overbalances the slight disadvantages of this loss in a reflex circuit by being a quiet and distortionless detector. * * * A capacity of .006 is desired. The highest capacity con- densers that can be gotten are .002. How can the differ- ence in capacity be made up? In the case of a certain fixed capacity being wanted, where there are a number of condensers of smaller value at hand, the higher capacity may be obtained by placing the condensers in parallel. Thus it is seen that if the desired capacity is .006 and there are three .002 condensers used in parallel, the desired capacity will be obtained. * * * What is the effect of connecting condensers in series? When condensers are connected in series it cuts the efficient capacity down in direct ratio to the number of condensers as compared with the capacity of each. Thus for example three condensers connected in series, the capacity of each being .002, the method of finding out the capacity is as follows: Take the capacity of 1 condenser as .002. Divide by the number of condensers in circuit thus: .002 -f- 3 = .000666, or the capacity of three con- densers in series. When making fixed condensers, state the precautions that are to be observed. In the manufacture of condensers, if they are to be packed (rolled) the best method of making is to use tin foil and waxed paper. The paper used should be at least one inch larger all around than the foil. The waxed paper should be heavy enough to stand the strain. The lugs for connections should be taken off opposite sides. * * * When a receiving set is installed, and refuses to work, wliat should be done to test it? In the case of a receiving set refusing to work when installed, the following should be done: See that the tube is lit properly. If there is no click when the B battery is connected, reverse the leads. If variable condensers are used across the secondary, rotate them to determine if they are short-circuited. If this is the case a series of loud clicks and knocks will be heard in the phones. See that the antenna is not grounded and that it is connected to the proper post of the set. See that all the lugs of the tube are making connection with the proper post of the socket. The lugs of the socket sometimes become bent and do not connect with the post, so see that they all make good con- nection. * * * Can a tube filament be repaired after the manner of a regular light bulb, by tapping the side of the glass? This cannot be done, because of the fact that the filament in a tube is short and stretched tight. When burnt out, it fuses short because the filament is extremely thin. This leaves the filament too short to enable any jar to allow a short circuit to again connect the wires. * * * In the new l}4-volt tubes, vibrations are very apparent. What can be done to reduce the noises? The socket should be mounted on a pad of thick felt or soft gum rubber and not screwed down. Glue should be used to fasten both the felt on the sub-panel and also to fasten the socket proper on the felt. This will reduce the vibration of the elements of the tube and decrease the noises. SECOND DISTRICT RADIO CONVENTION A BIG SUCCESS THE third annual convention and radio exhibition of the Second District Ex- ecutive Radio Council, opened at 2 P. M., Thursday, March 1, with a bang. In con- trast to the convention held last year, both from standpoints of beauty and usefulness, 'it overshadowed the second annual meeting as completely as a Rolls-Royce outclasses last summer's Ford. The exhibits, which are really the hit oi the show, were arranged in a most interest- ing and unusual manner. A point of note is the fact that the exhibits have practically the same amount of space allotted to each. Therefore, they stand out because of the value of exhibits themselves, rather than the amount of space allotted to them. This is a noteworthy idea, as no unfair comparisons can be drawn from the consideration of space alone. The booths as allotted for the exhibi- tion were occupied as follows : Booth 3. Westinghouse Union Battery Co. 4. Electric Storage Battery Co. 5. Radio Corporation of America. 6. Mortimer Radio Co. and Advance Metal Stamping Co. 7. General Radio Co. 8. Acme Apparatus Co. 9. W. J. Murdock Co. 11. Jefferson Electric Mfg. Co. 12. American Radio Relay League. 13. F. A. D. Andrea. 14. Experimenters' Information Service. 15. Federal Tel. and Tel Co. 16. Diamond State Fibre Co. 17. A. H. Grebe & Co., Inc. 18. Executive Radio Council, Second District. 19. De Forest Radio Tel. and Tel Co. 20. Marco Storage Battery Co. 21. The Bristol Co. 22. Jewell Electrical Instrument Co. 23. Adams-Morgan Co. 24. Novo Mfg. Co. 25. Allen D. Cardwell Mfg. Corp. In the Butterfly Room, which is right across the hall from the main exhibition, are the Club Exhibits. The following clubs were represented, in the booths allotted: Booth 26. Radio Club of Brooklyn. 27. Hackensack and Ridgefield Park, N. J., Radio Clubs. 28. Chelsea Radio Association. 29. Radio Association of Greater New York. 30. Ridgewood Radio Club. 31. Hudson Radio Club. 32. Department of Commerce. 35. Bronxville Radio Club. 36. Bronx Radio Club of New York. 37. Hill City Radio Club. 38. Staten Island Radio Club. 39. Radio Club of Jamaica, L. I. 40. Radio Division, Hudson River Yacht Club. 41. Bushwick Evening Trade School Radio Club. 42. Roselle Park Radio Club. 43. Camp Walkill Radio Club. The club exhibits at the third convention overshadowed those of all previous years, even beyond comparison. One of the finest installations of the radio clubs was that made by the Radio Division of the Hudson River Yacht Club. In the next issue of Radio World will be published illustrations of the various ex- hibits and news of the convention. One of the features of the show was the fact that A. H. Grebe & Co., Inc., installed a complete 500-watt transmitter under a special license to operate three days, die call being 2CYT. Radio and the Churches ROGER W. BABSON, the well-known statistical expert, is quoted as saying: ■ "A hundred thousand churches in this coun- try and their millions of members little realize how their institutions are to be changed by radio broadcasting. People, like water, travel along the lines of least resist- ance. If they can hear at home by the fire- side, on the radio, the same service that they would otherwise have to go out and hear, they are apt to remain at home and use the radio." Digitized by Google

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RADIO WORLD 15 Radio and the Woman By Crystal D, Tector UNKNOWN to F. H. the other day I visited town and, going to one of the largest radio stores, bought all the necessary parts for the "Flewelling Circuit." Two days later, when hubby arrived home on the 6:10, he was much surprised to find that I had taken his set and put it away, and in its place was my work of art. Well, you never saw a more surprised man in all your life. He just couldn't understand how any woman (he generally calls them "mere womings") could make a set. It worked so well that we decided to let the old set stay upstairs and play around with the "New Flewelling" awhile. You want to try it, girls ! It's more fun than making a cake or a new dress, especially if you surprise some one with it. And the satisfaction you get out of it when you can stick up your chin and say : "Oh, yes ; I made it myself!" * * * While we are on the subject of making things, I know tfiat there are a lot of men in town that have turned out to be real handy around the house just by showing the folks that they could make things if they really wanted to. They had the bad habit of telling their wives and mothers, "Oh, send for the carpenter. He'll fix it. I'm too tired — hard day at the office," and all of that. But now that they have demonstrated that they can do something if they feel like it the plumber and carpenter don't make so much money driving a few nails or fixing a leaky faucet. * * * I had quite a time finding the correct way to solder, and nearly gave it up as a bad job; but by wasting plenty of Radiograms ALL police and fire-alarms will soon be broadcast if a series of tests which William B. Quinn, of Jersey City, is conducting are successful. He intends to install an intercommunicating sys- tem in every police and fire station throughout the city, and equip all the police and fire stations witk receiving apparatus. ■ * * * HOPE can now be held out for the deaf if experiments made by Dr. MacLeod Yearsley, of London, a famous aural surgeon, turn out successfully. He recently was inspired by the report that a deaf man 77 years of age, was made to hear the human voice for the first time in 30 years through a radio receiving set. Taking Harry Shwer, a boy 13 years old, who has been deaf from birth, he made the experiment of placing him before a loud speaker. The youngster quickly evinced the fact that he could hear, by tapping his foot in rythm with the music that was at the time being played. Dr. MacLeod Yearsley holds great faith in re-educating the deaf to hear by means of radio and thinks that this is the biggest step in that line that has been accomplished. solder, burning the table and my hands quite a few times, I finally found out that I had to clean the parts, then put a little flux on it (funny brown stuff that smells terrible when you put the iron on it), and not let the iron get red hot. It surely is a great satisfaction to see the parts stick together after you have "muffed" it a dozen or more times and then found out the right way all by yourself. * * * The large New York department stores are making quite a lot out of the radio craze these days. Last week a few of my friends and myself went shopping, and, of course, we had to do two things: one was to visit the millinery department and the other was to look around the music department. Imagine our surprise when we found that the store had given over half the space that they had for the music department to an up-to-date radio department, with plenty of sets and nice young men to demonstrate them for us. We listened to more sets and things than we had ever known existed, and the clerk was such an agreeable chap. He never did get tired of explaining just how everything worked, and it was perfectly understand- able, too. Some of those radio clerks like to hear them- selves talk about "super-impose, self-heterodyne" and any number of fancy technical terms which very few people understand, and it is a welcome relief to have somebody talk in such a way that you can understand. Of course I don't mean that I personally object, but it seems that the "experts" are acknowledging that just because they under- stand those terms there is no reason why every one should. WHAT is said to have been the first time that proceedings of an important stockholders' meeting have been broad- cast, was recently accomplished in Chicago, when the Chicago Edison shareholders conducted a long-distance meeting and voted by radio an increase of $20,000,000 in the capitalization. * * * A COMPLETE broadcasting equipment was installed at the Long-acre Theatre in order to insure the successful broad- cast of "The Laughing Lady" on March 2. This play was broad- cast through Westinghouse, but the complete speech-amplifying and power-amplifying apparatus was installed at the theatre itself, to insure the successful broadcast. * * * A RECORD for 9 KP, the radio station of A. J. Leonard, Jr., of Chicago, was made recently when reception of his voice and CW signals were heard at the Awarua station at Invercargill, New Zealand. This is a distance of 8,000 miles, and clear reception was reported. This station is an amateur-owned and operated station and is rated at 500 watts. It was constructed entirely by the owner. New York Department Store Holds Radio Exhibit AN interesting exhibition of radio goods was held last week at Gimbels' depart- ment store, New York City. This exhibit, which occupied half the fourth floor, was one the neatest laid-out showings yet seen and was appreciated by large crowds. This exhibit was held mainly to acquaint the public with the latest in radio and also to show people how broadcasting is actually accomplished. For this latter purpose, the Westinghouse station WEAF installed a complete station in the center of the floor arranged in such a manner that the visitors could see exactly how it is done. The broad- casting was transmitted over land wires through the agency of power amplifiers to the operating and transmitting rooms at Walker Streets, New York City, where the actual broadcasting was done under the most modern methods. All of the latest apparatus was shown and quite a few of the exhibits related to the improvements that have been made in radio in the past few years. This was done by arranging the apparatus in use three and five years ago in such a manner as to show by steps the improvements that have been wrought in all the different lines. This was a very instructive and interesting way of conveying to the uninitiated by visual means just what has been accomplished in the way of improvements. The huge ungainly look- ing keys that take up half a table, the noisy, dirty spark gaps that look like a monstrous static machine, the "coffins," or transform- ers, and everything that used to be consid- ered the height of perfection was exhibited right alongside of the present up-to-date apparatus that has taken its place. New Zealand Hears Troy, N. Y. THE broadcast of radio telephony from the Rensselaer Polytechnic Institute, at Troy, N. Y., on March 1, was heard dis- tinctly in Invercargill, New Zealand. Both the speech and music were reported very clear and fairly loud. Not much interfer- ence was noticed. This is a new record for distance, as the receiving station was over 10,000 miles airline distant from the trans- mitter. The Troy station, WHAM, has recently established several long distance records, but the present one excels them all. It is a noteworthy fact that this station is not a commercial project, being merely established as a medium through which the students of the college may, through actual experience, become acquainted with the theory and practice of radio telephony and broadcasting methods. Digitized by Google

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16 RADIO WORLD (C. Kadel & Herbert) Mme. Ganna Walaka, lyric soprano, when ihe tariff for the benefit of a radio audience from the Waldorf Astoria studio of radio station WJZ. This was her initial appearance after her arrival in America. (C. Underwood & Underwood) Mile. Andrea Lafayette, descendant of the famous French general and patriot, listening in to the super- regenerative tat, nicknamed the "Rolls Royce" of radio receivers, at the Permanent Radio Fair, Hotel Imperial, New York City. Mile. Lafayette distinctly heard a message of welcome broadcast from tha Los Angeles "Examiner," Station KWH. (C. Kadel & Herbert) Mr. Harschel Jones, the man responsible for the fact that market reports are being broadcast to the agricultural industry. It was only through tention to the matter that the Government finally decided to I " port* that help the farmer and people in the outlying di It is such men as these that realize tha importance of radio to the farmers. Pictorial News Culled For Radio W( Captions by Robert t(". Kadel & Herbert) Dr. Francis _Leroy Satterlee, noted X-Ray specialist, and Us radio set. This circuit was demonstrated to all engineers of the world and proclaimed to be tha most startling discovered in a long time. The set Is incapable of oariHartng a (C. Kadel & Herbert) The head of the Department of Physics at Ford- ham University, New York City, Rev. Francis Duffy O'Laughlin, S.J., Ph.D.. who realized in the beginning the importance of radio and was instrumental in having one of the finest radio equipments installed at the University. The photograph shows Dr. O'Laughlin operating the model receiving station at the University. T (C. Kadel & Herbert) Gladys Ward, of the "Ziegfeld Follies," operat- ing the super-regenerative set at the Permanent Radio Fair, New York City. Mia* Ward, who ia not very well acquainted with radio, hearing a buzz in the receivers and hearing somebody mention "B" batteries, immediately laid down the receiver* and fled, saying that aha didn't want to be stung. She wasn't. Digitized by >

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RADIO WORLD 17 from Everywhere Id Readers . Dougherty (C. Kadel & Herbert) Thousands of listen- ers have heard the chimes ring out when Station WOR, of L. Bamberger & Co. Newark, N. J., signs off. The photograph shows Miss f. E. Koewing, one of the operators of the sta- tion, ringing the eve- ning chimes of WOR. Miss Koewing has the distinction of be- ing one of the first women broadcast (C. Underwood & Underwood) -own making the lntrod„ctory ^J^S^^SSM (C. Photo News) A miniature radio re- ceiving set built into a small filing cabinet The set is a one-tube receiver and utilizes honeycomb coils for the inductances, as can be seen in the photograph. It was built by Milton E. Brounshield, of New York, and was one of the prize-winning en- tries of the amateur radio set contest held at the Hotel Imperial New York City. (C. Kadel & Herbert) A modern plumber has Installed a radio *ft in his shop to draw trade and «J>e men contented, while a phunber^S^has bee"" °*V'r """" "time to sit around," cven^^his^hop' so must take It for granted thatTe is either an ardent radio fan or else must want to be. T (C. Fotograms) A new device which calls radio Into use has been perfected by Prof. Leo Jacobson, of Charlottenburg, Germany, for strengthening the beats of the heart. It was found especially useful in the cases of men doing strenuous labor, such as athletes and people called upon to eprform serious physical tasks.

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18 RADIO WORLD Answers to Readers 1. / have an antenna of two wires, each 175 feet long. Is this too long? 2. What coils should I use to tune in POZ? 3. Please give me a panel layout for a honeycomb coil set. — lack Alison, 374 Broad-way. New York. 1. Your antenna is too long for efficient short-wave work, but for receiving the long- wave stations, such as Germany and France, it is O. K. For broadcast receiving and 200-meter work a single wire, 80 to 100 feet long, is sufficient. 2. You should use 1250 as a primary. 1500 as secondary and 750 as tickler. This is approximately the correct set of coils for the work, although you may have better success with 1300 as a secondary, depending entirely upon the construction of your set and what condensers you use. 3. A layout such as you want will appear in an early issue of Radio World, with a complete description of a very flexible set embodying honeycomb coils. / am unable to erect an outdoor antenna, hafing haa to use a flat loop or wire, as shown in the accompanying droning. It is 125 feet long and located in the attic, 20 feet high. Will it work with the enclosed hook-up which was published in Radio World, dated February 17, on page 11, by C. W. May? Will 1 be able to receive NAA by using this circuit ? — Joe P. Hamer, Nevada, M issouri. Yes, this circuit will work with the antenna you mention. Care should be taken that the antenna is well insulated at all places. Thi-; circuit will allow you to re- ceive all wfi »le lengths by slipping in the honeycomb .oils in the space left for them. This circuit also permits you to load up to 24.000 by the use of the honeycombs. In connection with the Ftewelling circuit published in Radio World, dated Feb- ruary 24, will you kindly advise me of the following : i constructed the set exactly 1. Your hook-up is entirely wrong. It should be as per diagram. As it is the line shorts the tickler and also the plate battery, which is absolutely wrong. 2. It is not absolutely necessary to use Hook-up given in response to inquiry of Mr. Carl Hausing. The 7 plate condenser connected across the primary and tickler circuit tend* to increase regeneration and affords easier control. u.v.zoo, fiudr'o Frequency Transformers Vcfrbmeter\ _ _J Vern/er 200 Ohms VvVVW 22 zV i|i|i|iWi|iK i if son. It is the conventional regenerative hook-up embodying two variometers, a vz The oBBdsnawi across the primary of the transformer* may be dispensed with if na Hook-up furnished in ii^puuse to query of Mr. C W. Jan coupler and two steps of audio frequency amplification, sary. but, if used, will tend to decrease any tendency of the amplifier to howl and distort signals. The potentiometer should be 2M-4M ohms resistance for most tubes. Kindly send me a hook-up for the follow- ing apparatus: One moulded bakelite vario- coupler; two moulded variometers; one 43- plate variable condenser; one 23-plate variable condenser; one potentiometer; three rheostats; three tubes; two transformers; two double-circuit jacks; one single-circuit jack; necessary grid leaks and condensers. — G. W. Jamieson. 209 Wellington Street, W., Chatham, Ontario, Canada. The hook-up you request is published herewith. On page 16 of Radio World, dated Feb- ruary 10, you publish a picture of Dr. R. S. Piper and his one-tube set with patented coupling transformer. Where can I obtain this transformer ? Where can I obtain a copy of the hook-up used? — Letvis McMahan, ll2'/2 S. Denver Street, Dallas, Texas. We refer you to the photographers of •■ picture — Underwood & Underwood, 417 ^ \ i iiue. New York City. They can all information on this subject if rite them. as per instructions with the exception of using a 43-ptaie vernier in the circuit instead of the .0005 mentioned. I am using a/WD-U with 90 volts on the plate, and cannot get anything but local stations very weak. What is my trouble? — Michael Van Praag, 73 West 95th Street, New York City. As explained in the text, this circuit is somewhat critical, and it is absolutely neces- sary to use the correct capacities as shown. If you deviate the circuit will not work properly. The condenser bank is also very important. It should be hooked up with the correct capacities just as shown. Try re- hooking this set, using the correct capacities. The antenna should be hooked to post marked A in the circuit. 1. / am enclosing a hook-up that I copied out of a radio paper we get out here, but fail to get any results. What is the trouble? 2. Is the apparatus specified absolutely necessary? I am using an all-wave coupler instead of the one specified. Will this make a difference? — Carl Housing, Box 61, Topcka, Kansas. the exact apparatus specified to such a great extent. Any coupler can be used. This also applies to the condensers. As long as they are of the correct capacity it does not matter what make they are. » * » 1. Where can I get a wiring diagram of the Rcinarts tuner circuit? 2. What parts are necessary? 3. How many plates in a .0005 and .001 condenser? 4. Is radio frequency advisable with the Reinarts hook-up? — Richard Burgess, 230 Main Street, Burlington, Vermont. 1 and 2. We refer you to the Reinartz tuner circuit, published in Radio World. dated January 13, in answer to a question on the same subject by C. W. Stewart. 3. The construction of a .0005 variable condenser generally incorporates 12 station- ary and 11 movable plates, which make 23 plates. In the .001 there are 22 fixed and 21 movable plates, which make 43 plates. 4. Radio frequency with a circuit such as this is not advisable, but more audio- frequency can be added. Preferably not more than two extra steps as it is not ad- visable. Digitized by Google

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RADIO WORLD 19 Latest Radio Patents Modulating System for Transformers spacing between turns will be maintained. In carrying my invention into effect I place along each side of the framework over which the wire is wound a closely coiled spiral of line wire. W hen the grid is wound on the framework each turn slips between two adjacent coils of the spiral, and one or No. 1.442.14*: Patented Jan. It, ltZJ. Patenteal Raymond A. HrUinc, Eait Orange, N. J. MR. HEISING'S invention relates to means for generating, modulating and Hcisinf '■ Modulating Syatam lor Transmitters. transmitting electrical oscillations, and more particularly to generating oscillations by means of electrical discharge devices An object of the invention improvement in the manner in trical discharge devices may be assoi iated in signaling and other systems, and also to provide a system in which a plurality of electrical discharge devices are ass -iated with suitable circuits to act as osculation generating means. Further objects are to produce a signal- ing system with which modulated and un- modulated signals may be sent, am i which a vacuum tube oscillates dircctl> into an antenna. The invention is exemplified herein in a radio signal transmitting s>ste— wherein the antenna itself is included in and form* a frequency-determining element of a high- frequency oscillating circuit, and is directly associated with a vacuum tube oscillator or a series of vacuum tubes tiling as an oscillator. The oscillation frequency is determined by the circuit, which includes the antenna. Vacuum tubes for modulating have been provided to effect the signaling modulation of the oscillations to be transmitted. devices. jU-^V — r" 1—, j is to effect anl-^ai i\ ^-W in which elec- ^sj- 1 M J i New Method of Modulating Carrier Waves in Telephony No. 1,444^4S: Patented Fab. t, UQ. Paten tea: Raymond A. Hoisln>, Mill burn, N. J. THE invention of Mr. Heising's relate* to oscillation generator circuits and to signaling by means of modulated carrier currents or electromagnetic waves. of this invention to provide combinations of devices for and methods of signaling through the agency of successively modu- lated currents, the devices being so designed and associated that the above mentioned or other undesirable modulation is prevented. Since it is sometimes desirable to trans- mit a plurality of signals upon a single high frequency carrier wave, arrangements for multiplex signaling are also provided. In the operation of these there is produced a high frequency carrier current modulated in accordance with a plurality of intermediate frequency currents, each of which is itself modulated in accordance with a signal or low frequency current. SlanalHnc by Moans of Modulated Carrier Currants. One object of the invention is to associate, in a novel manner, two or more electron discharge oscillation generators. In the operation of signaling systems wherein the principle of successive or plural modulation is employed, it is sometimes de- sirable that direct modulation of the high frequency carrier current by the signal cur- rent should be avoided. It is another object Internal Construction of Vacuum Tube? No. 1.444.4M: Patented Fab. 4, ISO. Pa* WW. C. White, Scbaawetady, N. Y. MY invention may be applied to electron discharge relays or amplifiers of the pliotron type, and particularly to the con- struction of grids for such devices. In apparatus of the type mentioned, which comprises an evacuated vessel containing an incandescent cathode, an anode and a grid electrode interposed between the cathode and anode, it has been customary to form the grid by winding a plurality of closely adjacent turns of fine wire about a support- ing framework. Difficulty has been experi- enced in the construction and operation of such apparatus by reason of the fact that the turns of wire are apt to become loosened by reason of the unequal expansion and contraction of the wire and the framework. As a result the spacing between the turns may be changed, and in some cases the wire may move so as to come in contact with other parts of the device. The object of my invention is to over- come the above mentioned difficulty and provide a simple and efficient construction in which the grid wires will always be re- tained in their proper position upon the supporting framework and the desired White'a Matbod of Vacuum Tuba Construction. more of the coils of the spiral will be inter- po>cd between adjacent turns of the grid wire. A Compact Condenser No. I.444J14I Patented Fab. 4. ISO. Pateataoai B. Amsa and P. J. Clmm, Lswofl. Mass. ""I"* I IE invention of Messrs. Ames and Gil- * linson relates to electrical condensers and has for its object a condenser which is simple to construct, which is compact in form, which can be tightly compressed to expel any air trapped therein, which will *f*9 a- fit into a magneto rotor or other restricted space, which has a large area of contact be- tween the layers of conducting material and the terminals, whose layers of insulating material are symmetrical and imperforate, whose layers of conducting material are im- perforate and formable from a band or rib- bon of material, whose parts are secured together by means not extending through the alternate layers of insulating and cou- (hirting material, and which is of generally improved construction. Digitized by Google

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20 RADIO WORLD New Records of The DX Nite Owls Wants to Hear from You From Weston C Libboy, Harlowtsn, Montana HERE they are: WAJZ, 1,612 miles, heard once. The following heard any nite: WBAP, 1,025 miles; KUO, 850; KPO, 850; KFI, 850; WFAF, 470; KLZ, 470; KFGL, 470; CFCN, 350; KFCK, 725; Fl*. 1. Hook-up uMd by Mr. Ubbey. It Is practically Am suns as ths Millar tive hook-up. Ths varli ^1 PatJ Fig. 2. On* of ths simplest rsf ensrativo cir- cuits, but ons that is efficient on phone work. The potentiometer Is absolutely essential. Fig. 3. Modification of Circuit I. LI can be a -t-r but must be placed hi Inductive ' 2, which la a coil of 17S turns. * HE Editor si RADIO WOULD I to ttwlv* •dMtehts* M black Ink ar I pencil tram the "DX Nits Own)" whs la room as with a view ts Ssad hank-ops af year sets. The Utters hi ths RADIO WORLD. WOC, 900; WLAG, 712 miles. CFCA, 1,325 miles, heard twice; WOI, 800, num- erous times; WLAL, 900, numerous times; 9XU, WDAP, and KYW, 1,010, hear often. The equipment that I got these stations with consisted of 1 Cunningham detector tube, 2 Duck variometers, 1 Remler poten- tiometer, 1 Duck socket, 1GR grid conden- ser and leak, Murdock condenser, a Remler aerial, 80 feet long, 30 feet high at lead-in end, and 15 feet high at free end. Honeycomb coils ought to work all right in 02, or a bank wound coupler. I've not tried'either yet, but am going to. I would like to hear from any one trying either Dl or D2, letting me know what re- sults they get. ♦ » » NPG at 1 A. M. From Dr. Arthur R. Carvey, IM Moody St., Waltham, Mass. I ENCLOSE picture of my latest home- made regenerative set, three stage audio frequency. It will be noted that I am using the duo lateral coils which I consider the best and only tuning inductance; one jack for the detector tube, and two jacks con- Dr. Carvsy's Home-Made Regenerative Set nected in series which may be used on either the second or third stage by means of an anti-capacity switch mounted nearest the last jack. The other anti-capacity switch is for disconnecting the A and B batteries. My first set, if I may call it a set, was in 1908, when all that could be heard was an occasional dash or dot and the time signals, from Boston, I believe. A 75 ohm receiver, a crystal detector and a home-made tuning coil completed the outfit. I had only reached the_ loose coupler stage when the war brought about the end of the amateur radio activities. The first time the voice was heard through the air stimulated interest again and led from one bulb to the present outfit. The box is not compact, but is about 24 by 15 by 10 inches. Everything is so ar- ranged that new hook-ups may be tried out with a minimum of trouble, and to this end I have a terminal rack or shelf under the bulbs and transformers. All battery con- nections and jacks come to these terminals, and it can be seen that there is no cutting of soldered connections for trying a new hook-up. There is room in the box for the B batteries and these also go to separate terminals, and a dead battery is easily re- moved or tested. Many have found trouble working a third stage and so did I. A poor or dead B bat- tery will cause much trouble and the in- ductance of each circuit must be under con- trol. I have obtained excellent results with a slight loss of volume by using a fixed con- denser .0005 across the plate and grid con- nection of the last tube. I think, however, this would be an excellent place for a small variable condenser. Although it is claimed that duo lateral coils are harder to tune, I do not find it so, and enjoy the advantage of listening on any wave length, making it possible, as I have done, to listen to the high power French stations and time signals all over this coon- try. Recently I listened to NPG, at San Francisco, ticking off the 1 A. M. signals. P. S. — My antenna is wholly indoors, be- ing about 120 feet of bare wire in the attic of the house. » » * "Clear and Loud" From Lloyd R. Dickens, 222 Windsor An, Windsor, Oat. POSSIBLY some other readers of Radio World may be interested in the perform- ance of WD- 11 tubes, so I will describe re- sults obtained here. Some months ago I constructed a regen- erative circuit, using hook-up shown and in- stalled it in my home in Stratford, Ont, 150 Vorr.GrntlfviA. r— — — ^ /.j>jk , ^jipjl Diagram of circuit with which 1_ it- had accomplished marvsDoua results, It is a •ingle circuit receiver using the rotor far a tickler. miles northeast of here. I use WD-11 tube and my aerial consists of 100 feet of wire strung in the attic. Some of the stations heard from follow: WW J, 150 miles; WCX, 150; WBV, 350; WGY, 350; WEAF, 400; WJZ, 375; WOC, 525; WKAG, 450; WDAF, 775; CKCB, 900; WDAO, 1,140; WPA, 1,175; KDZP, 2,100 miles. These are not all by any means, but will give some idea of range covered and I think the last one, KDZP, Los Angeles, will open the eyes of some. This was logged on the night of Feb. 6, and again on Feb. 8. It came in quite clear and loud. » » * Glad to Hear from DX Fans From M. F. Drudy, Jr., Woodhaven, N. Y. MY experience with the short wave re- generative receiving sets and the honeycomb, or duo lateral coil receiving sets, prompts me to defend the latter, notwith- standing the criticism that the honeycomb is inefficient and unsatisfactory. In one evening I have heard as many as seventeen different stations, distances rang- ing from a few miles to thirteen hundred and fifty miles ; tuning out local stations and bringing in the most distant with perfect {Continued on page 21) Digitized by Google

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RADIO WORLD DX Nite Owls (Continued from page 20) ease. Furthermore this is done with an outside aerial only fifty feet long, including the lead-in. My location is 8825 Seventy-sixth street, Woodhaven, Long Island, N. Y., and would be glad to hear from any DXers. From January 8 to February 8 I have re- ceived the following stations: WAAM, KDKA, WGY, WEAF, WHN, WOR. WJZ, WGAA, WDT, WDAP, WBAN, KYW, WIP„ WWJ, WFI, WSB, Atlanta. Ga.; WRW, WBZ, WHAS, WBS, WDAF, Kansas City, Mo.; WLW, Cincinnati, O.; PWX, Havana, Cuba; WOC, Davenport, Iowa; WHAM, WGM, Atlanta, Ga.; WGI, WOO, KQV, WEW, St Louis, Mo.; WAAB, New Orleans, La.; WGAM, Orangeburg, S. C; WGR, WBAP, Fort Worth, Texas; WMAK, WMAQ, WHB, Kansas City. Mo.; WBT, Charlotte, N. C; WMC, Memphis, Tenn. With a loud speaker I was able to bring in such stations as Schenectady, Pittsburgh, Atlanta, Memphis, Springfield, Buffalo and Chicago. Sitting twenty-five feet from the set, we could all hear plainly and pleasantly. And Without Amplification Praoi A_ Rlddefl, Chicago ENCLOSED find the hook-up of my honeycomb receiver which you may pub- lish on the "DX Nite Owl'' page. The stations I have heard from Jan. 1 to date are: KYW, WMAQ, WAAF. WDAP, up umd by A. Riddel for on* WD- 11 The condenmr acrou the wo tickler enables the wt to oeclllate c_ much lower wave leagtha. WBU, WHB, WPAD, WGAS, WGY. WWJ, WGM, WAAK, KDKA, WSB, WOC,. WGAN, WHAS, WDAA, WOAG, WCAF, WAAM, CFCF, WJZ, 9ZAF. WOR, WGAK, WWI, GFGA, WKY, WOE. WLW, WIAO. WHAI, KSD, WBAP. WCAE. WNAV, WDAF. All were heard on a WD-11 tube without am- plification. » « • Records By Three Sets From Floyd Mayor* Du Quoin, DL Ip N CLOSED you will find record of the *-* stations that I have received with my three sets: Crystal Detector— WOC, WSB, WHB, WDAF, WGM, WWT and KSD. Record with my 1-tube set (variable condenser and variable coupler) is nearly the same as that of my honeycomb coil 2-stage set. The record of both combined is as fol- lows: WOH, WLK, WSY, WOK, KHJ, KFI, DM4, KFAF, WDAL. WSW, WGM WDAJ, KYW, WAAF, WMAQ, WEAC. WOZ. WOI, WIAS, WOC. WGAM. WJAM. WEAB. WHAE. WGF, WBL, WAAP. WEAH. WHAS, WIAR, WCAQ, WAAC, WMAF. KOP. WWJ. WCX, WMAT. WLAG, WAAH. WOS. WOQ. WMAT, WEAK, WCK, WEW. WMAY, WOAL. WNAL, WOR. WMAK. WEAF. WHAM. WBL, WGY, WLW, WJAX, WKY, WLAL. WNAD, KDKA, WCAE. WQAA, WFAT, WQAQ, WCM, WFAA, WBAP. WPA, WKAL. WOAI, WFAH. KDYL, WIAO, WPAH, WGR, KFDF, CFCN, CGCJ. CFCA, PWX, KLZ, WAAZ. I also receive PWX, KHJ, and Canadian stations regularly and will be glad to fur- nish hook-ups for either of the three sets. My sets are all home-made. I constructed them all myself. • • a Listens Every Night From Thee. A. Peacock, MS Porta*. St, Weet- field, N. Y. FT ERE is a list of stations I hear from *■* every night. I can hear them very plainly: WGY, WGR, WOR, CFCA. WHAS. WEAO. WEAF, WDAP, WJAX, WWJ. WJZ. WPAB, WJZ, WLAB. WHB, WEAE, WBAP, WDAJ, 9XD, KDKA, WOC LMC, and also have heard from Omaha, Neb. e e * On a Two-Stage Amplification From Richard Loughran, Creanaborf , Pa. I HAVE received the following on a two- stage amplification and one detector : WSB, WLC, KFV, WEAD. WLW, WNAP, KYW. WDAP. WMAQ, WWI, WNAC, WNAF, NBZ, WEAF, WGV, WRW, WHAZ, WHAM, WDR, WCAE, KDKA. WJAS. WBAK WIP, WFI, WQAA, WHAS. KSD, WHB, CFZC Every one of these I heard plainly and distinctly. * • • A Happy Family From M. J. Wlgmm^MW Addtoon St, BEING one of the happy family of readers of your magazine I am sending you the hook-up of my outfit that has been a great comfort to our whole household. We have so far been able to hear on just the one tube the following broadcasting stations: WDAP, KYW, WAAY. WBAA, WBAD, WBAP. WBAY, WBS. WBT, WBU, WBZ. WCAY, WCX, WDAE, WDAF, WDAJ, WDAY. WEAB, WEAF. WFAA, WFAC, WGAY. WGM, WGY, WHAA, WHAS. WHB. WJAD. WJAP. WOC. WRR, WHB, WJZ. WWI. CFCF. WBZ. KSD. WYJ. WPA. KDN. KHJ. KLZ. WOS. WPM, KDKA, WEAB. CHBC, KDYL. Stasia circuit racetvor ueed by Mr. WlfMaa. Note the novel method of geMae h ■death by the oat of separate coda m i imniillaa with the My place of residence, where my family and outfit are, is at Green Bay, Wis. My business being in Chicago I do not per- sonally hear very much, but my wife and children have the pleasure every niRht. My hook-up and record you may publish in one of your issues if you wish as there may be some brother or sister fans who may be interested. (.Continued on page 25) The Power Amplifier for your Magnavox Radio THE Magnavox, in reproducing with extreme sensitiveness every signal supplied to it from the receiver, must necessarily re- produce any extraneous sounds which may originate in the receiver or power amplifier itself. Therefore, to obtain all the won- derful results of your Magnavox Reproducer, use it with the Mag- navox Power Amplifier. R-2 Magnavox Radio with 18-inch I R-3 Magna iih 14-in THIS instru- ment is in- tended for those who wish the ut- most in ampli- fying power : for large audi- ences, dance halls, etc., but requires only .6 of an am- pere for the field. vox Radio SAME in principle and construc- tion throughout as Type R-2. Is ideal for use in homes, offices, amateur stations, etc. Requires one ampere field cur- rent from your filament battery. Magnavox Power Amplifier— Model C CAN be used with any "B" Bat- tery voltage which the power tube may require for best ampli- fication. The facilities and experience back of each piece of equipment bearing the Magnavox trade mark are unrivalled anywhere in the world. V . ■ ■ 1 products rruiy he hud of food draieri e\erru here. Write to ui for i The Magnavox Company Kew York Otfue. 370 Seventh Ave. Digitized by Google

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22 RADIO WORLD Advertising Rates: Display, $5.00 per inch, $150.00 per page. Radio Merchandising Classified Quick-Action Advertising, 5 cents per word. Telephone Bryant 4796 New Radio Firms (The new firms and corporations men- tioned in these columns can be reached directly or by communicating with the attorneys, whose addresses are given when ever possible.) Moss Radio Sales Co., 1 Beacon St., Boston, Mass.; Henry C. Lynch. Instrument Co., manufacture electrical and radio instruments, $50,000: William E. Orth, D. L. Diehl, John F. Whittaker, Harrisburg. (Cor- poration Service Co.) Iowa Radio & Electric Co., Ollie. Ia.; V. Gilbert Fye, successory to F. M. Andrews. Central Illinois Supply Co., 119 N. Main St., Abingdon, II).; Fred B. Ferris and Guy E. Bon- ney. Baldwin Radio Sales Corporation, 1800 Montrose Ave., Chicago; Henry T. Roberts and others incorporators. Schott Radio & Electric Co., Emington, 111.; F. H. and Wm. P. Schott. W. T. Rock, 2115 N. Main St., Bridgeport, Conn. Liddell Electric Co., 89 S. Main St., Waterbury, Conn. Sunflower Radio Co., Room 333. Sunflower Bldg., First and Main sts.. Wichita, Kan. Alexander Radio Electric Co., 1515 Olive St., St. Louis. Mo.; J. G. Alexander and others. International Electric Co., electrical supplies, $500,000, Wilmington, Del. (Corporation Trust Co. of America.) Firth Radio Corp., New York City, $5,000: M. Bemheimer, S. McGovern. (Attorney, E. Bern- stein, St. George, Staten Island). Hoosic Engineering Co., Hoosic Falls, N. Y., make electric specialties. $20,000; F. S. and S. P. White. (Attorney. E. Tiffiny, Hoosic Falls.). Owing to confusion caused by a similarity of names between the Radio Corporation of America and the Radiola Wireless Corporation, of New York City, the latter has decided to adopt the name of The Aerovox Wireless Corporation, based on its trademark. Radio Stocks (.Quotations as of February 28, 1923, fur- nished by Frank T. Stanton 6- Company, 35 Broad Street, New York City, Specialists in Wireless Securities.) Stock Bid Asked American Marconi Stamped 5c 15c American Marconi Stamped $5 $7 American Tel. & Tel 123 123'A Canadian Marconi 2yi 3J4 Dc Forest Radio 7 10 Dubelier Condenser ' 4y2 5 English Marconi com _ 11 15 English Marconi pfd 11 15 Federal Tel. Calif 5 6 General Electric 185 186 Hennessey Radio Corp. Pub 9 11 Manhattan Elec. Supply 55 56 Mackay Company com 115 116 Marconi Int. Marine 8 10 Radio Corporation com 3>$ 3J4 Radio Corporation pfd 3 3% Spanish Marconi 1 3 Western Union 116J4 117 Westingbouse E. & M 64 65 Coming Events PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to Mar, 1923. SOUTHWESTERN DIVISION. NATIONAL ELECTRIC LIGHT ASSOCIATION, Oklahoma City, Okla., March 14 to 16; S, J. Ballmger, secre- tary, San Antonio Public Service Co., Sin An- tonio, Tex. ILLINOIS STATE ELECTRIC ASSOCIATION. Chicago, March 16 and 17: R. V. Prather, sec- retary, Mine Workers' Building, Springfield, Ohio. Prevents Phone Tips Falling Out HP HE difficulty of preventing phone tips from falling out of binding posts and the poor contacts that often occur have been eliminated by Union radio phone tip jacks, made by the Union Radio Corpora- tion, Newark, N. J. Union radio jacks are especially convenient in CW circuits, WD- 11 connections, coil mountings, experimental circuits, or, in fact, any part of a set where quick changes are needed. In addition to accommodating any telephone cord tips manufactured they also can be used with several sizes of bare wire. To mount Union radio tips on any panel a hole is drilled, using a 7/64 drill, then the bushing inserted and the lock nut which holds the combination tension spring and soldering lug in place is screwed on. New High Power Wireless Station for Canada IT is reported that the Marconi Com- pany has matured plans for the erection of a powerful wireless station at Vancouver, British Columbia, which will cost $2,000,000. This station, it is said, will be one of the giant stations of the world, exceeding in power any other Marconi station at present in existence, and which will in effect make western Canada an important factor in world wireless communication, linking it up on one side with Australia and the Orient and on the other with Europe. Relaying and Broadcasting on Different Wave Lengths REPORTS doming from Cleveland that radio concerts from KDKA, the East Pittsburgh, Pa., broadcasting station of the Westinghouse Electric & Manufactur- ing Company were being received with greater volume than the broadcasting of local concerts occasioned little surprise to members of the radio engineering depart- ment of the Westinghouse company who had been experimenting with short wave broad- casting and relaying of KDKA's concerts. . It had been confidently expected that radio enthusiasts in Cleveland would be surprised to hear KDKA coming in with great volume as experiments in the relaying of short wave signals had been going on for some months under the direction of the radio engineers. Many fans of Cleveland are still puzzled at the good volume of KDKA's signals be- cause their city seems to be a perfect dead spot and has been so recognized by radio men for years. It has been said that get- ting into Cleveland via the ether is a task that radio experts have been working on for some years but with little success. This characteristic of Cleveland is one of the reasons that Frank Conrad, assistant chief engineer of the Westinghouse com- pany and a radio inventor who is recognized all over the country, chose to relay his short wave signals from KDPM, broadcasting station of the Westinghouse company located in Cleveland. His experiments were carried out through the assistance of L. W. Chubb, manager, and other members of the radio engineering department and the results at- tained through this method of broadcasting have been so good that a new era in radio entertainment may result. Short wave relaying is the newest method of radio broadcasting. To those who are unfamiliar with the terms it means in short broadcasting on 100 meters or lower wave lengths by a powerful station. These short wave signals are then picked up by a short wave receiver and in turn relayed through a broadcasting station tuned to 360 meters. The person operating a 360-meter receiver, of course, hears the 360-meter signals and will not hear the 100-meter waves as most of the receivers in common use will not work such short wave signals. Relaying these short wave signals as the Westinghouse company does through its Cleveland station is interesting to the radio amateur, particularly as the 100-wave meter signals are sent out simultaneously with the 360-meter concerts, neither interfering with the other. It requires special apparatus. For instance, at East Pittsburgh for this short wave broadcasting there has been in- stalled two transmitters controlled from the same microphone, one transmitter operating on 360 meters, the other on 100 meters. There are also two antennae, KDKA's long antenna which is 105 feet high and 200 feet long used for sending on 360 meters and the short wave antenna which is 35 feet high and 40 feet long, used, of course, for send- ing the 100-meter signals. A significant feature of this extremely short wave broad- casting is that very short antennae are used both for sending and receiving. In Cleveland the 100-meter waves are re- ceived on an eight-foot square loop for the reason that a short antenna is needed and that seems the best way out of the problem. The antenna is located inside the building and is connected to a single circuit tuner, detector and two stages of amplification. The output of this receiver is put into a 250-watt transmitting set, containing one oscillator and one modulating tube. The sending antenna at Cleveland is a duplicate of the one at East Pittsburgh used for sending on 360 meters, being 105 feet high and 200 feet long. There are, naturally, difficulties encount- ered in relaying these short wave signals. For instance, the small size inductances and capacities are difficult to construct. A slight change, like the swinging of an antenna will change the wave length and throw the re- ceiver out of tune. One of the reasons for using the loop as a receiving antenna is to guard against such mishap. Also a separate building on the roof of the Cleveland foundry of the Westinghouse company, located on the lake end of West 58th Street, had to be erected as the rattle of the foundry set up interference with reception. On the other hand the efficiency at 100 meters is much better on account of the lower electric Josses, which condition per- mits more radiation from a given antenna from the same amount of power input than is possible when sending at 360 meters.

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RADIO WORLD 23 PROTECTION Teleradio Filament Protectors For detector and amplifying tubes. Price, Single Pole, Mc; Double Pole, 8*cj Renewal Fuses. 10c ea. Teleradio Lightning Arresters Electrical No. 5»37 Th« oftl v ARREST- ER. ariTuted by the Na'*l Itnard of To- d*TWrit.'P». which, re- tails for 11.00. At year dealer" t. Otherwise lead Purckua Pries wi Siva Dealer'! Nana. TELERADIO ENGINEERING CORP, 4«S BROOME ST.. NEW YORK Makers of TciiTa-ilo c^iK-rscnsltlve Phones. The dials with absorption losses reduced to a Minin Specially di'dl^nM cross- *e■. ntcui.ro rtatl.n.'. Nit-alti al. 75c. Send stamp fur literature. Alden Manufacturing Co. Formerly Aldaa-Napier Co* party 92 Wills* St., Ssriaaftsld. Mass. Oast U NaEalDI IMMEDIATE DELIVERY FLEWELLING CIRCUIT ACCESSORIES 23 Plate PracMoo Cossdensers tLl* U PUte PracUkn Ccndaasssrra M Two- Coal Mounts Dwforwat LM>m&..... ....... 2.U D. L. SS Heueyctnb Coal l.«J D. L. 1% Honeycomb Coal 1.4S Variable Grid Lank only M Variaabt* Grid Lank and Good, Jt Hls-h Cracb BwkeUte Rheostat M W.D. 11 Tub* Socket M V. T. Tube Socket Ji Hatrd Rubber Panel, 7x1* IM No C O. D. Postage Paid Write for price* on other pant MAIL ORDER DIVISION ECONOMY RADIO CO. 1» Naaaau Street New York Cut. N. Y. ASSEMBLED No. IT Crystal Detector, Be each. Post Paid Astemble your own Crystal Detector. Complete parts for panel mounting; mv- MSaniUld, in envelope. Highest quality design end finish. Heavy brass nickel- plated with Bakelite Knob. MAIL ORDER SPECIALS Mai das Ceadeessr t .5* Daalai Phana Cllsa. 2 far 07 Nat*. Baldwin Tyae "C" Passes 0.4S HPMCO Sssa'al WO. 1 1 Traasfsrtasr 2.** II Plata Variable Csndsesar. Red Maided a tads '•»« 21 Plata Casswaser 1.14 43 Plate Candeaiar t.7i 3- Maldad DUI 21 Hedden Place Machine Co. Musfaaterws at RPMCO WIRELESS PARTS 4S Harden Place East Orange, N. J. Subscribe tfirect or through . news dealer. $8.00 • year, $3.66 sis months, $1.56 three month*. Riufie World, 1463 Broadway, N. Y. C Broadcasting Bill's Radiolays By WlUASf E. DOUGLASS ¥ N last month of many birthdays when •*• we heard so much on "Truth" just he- cause one bright young feller pulled a good one in his youth, I have often stopped to wonder, after all, if it was true that the world is gcttin' better cv'ryday. 1 wish I knew. Just the other night by radio some wise gazaboo's son handed out a lengthy lecture on the life of Washington. Yes, we told how George chopped cherry trees an' wouldn't tell a Ite — said the Father of our Country couldn't do it if he'd try. but I reckon Father Gcorgie never fooled with Radio, or stayed up all night to "listen in" or else I gne^s he'd know how hard it is to -tell the truth 'fruit stations you can Ret. when you've gone bugs on Radio an' got a wireless set. An' or course he never had to try new hook-ups every night that are printed in the papers. There ain't half of 'cm that's right. Gush I reckon Ananias with his whfrkcrs to his knees would be tickled half to death if he could work with some of these. He could tell the world about 'cm. how with just a single tul>e he could "pick up" far off Russia — if you b'lieve him yer a boob. Down in our town there's a feller with a hook-up that's a peach, when you hear him talk about it, it's an outfit with a reach. So I've often stopped to listen on this "wonder set" of his, hopin' he'd make good his story if his set is such a whizz. But of course when 1 drop in on him he's got a tale of woe how his set wuz working beautiful until an' hour ago, when this thing er that had happened. I remark "That may- be true." Then he springs a lot of alibis until the air is blue. Now you take that little set of mine with only the detector, it's surprizin' how I get 'em. it's a regular col- lector. With a pair of rubber earmuffs fastened on my head real tight, I pick up a hundred stations just as easy any night. Distance don't make any difference I can get 'em without tryin'. "I can't hear yet I" wha' ja say Mm? No, of course not, I'm not lyin*. (Copyright, 1M3. Wettinphous* Electric A Jfanw/ucturini; Company. ) FREE CATALOGUE Make D X Records With D X Supplies This Catalogue should he called "Recipes for Lonp Distance." It was written to help ama- teurs pull in the most distant stations. D-X- Radio Company Specializes on instruments built for Dis- tan-j. If you want to jump States or reach over mountains you must use the proper equipment. Our instruments do the trick. For Free Catalogue Write Department 84D D-X-Radio Company 123 Hberty St, New York Gty Radio World, 52 issues, $*L06. Sobscartbe direct or throafh yoar news dealer. $6.06 a year, $3.66 sis months, $136 three months. Radw World. 1463 Broadway, N. Y. C k^0^° to For Reflex Circuits, the 6« flex ha ye (our been proven the bra*. It ia in tbe world's loremosl Re 3.000 of wkich REFLEX DIAGRAMS continnslly appear in the daily pa peri and periodicals. lUaBo World of March 1 cneitaina SCT - THE RADIO STORES VARIABLE CONDENSER •fa/ateri ike ■ ■ r tmmimt to ettentM 10 Ike ore-radius of Keller tmt FleweUimf circmin. Die cast at a tor poets Rotor die. cast with abaft held ia true ecu. ter in Urge, brass bushings. No insulating material tapped— -metal inserts throughout. Precision workmanship. Best engineering LIST Zl Plate .SStS mid Capacity, ratio 12 to 43 PUte Ml mid $4.25 RADIO STORES CORP. .T.rn,.,.$4.75 J-/ M ■ f av f ■ w 2Z2 W*»t 34th 9tr**t i ft r thmt / NEW YORK CITY Digitized oy yaae. riawraaaii.

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24 RADIO WORLD Rente Synthetic Crystal* Sensitive over the entire surface. Price, including special catwhisker, tec Dealers — Write lor unusual proposition, THE AIREX COMPANY 237 Centre Street New York 120M-OHM L"» pri" 70s. RESISTANCES IN STOCK For Dm Ntw Sussr Clnalts RADIO STORKS CORPORATION DISTRIBUTORS 220 w. S4tk St. N. V. City Lsntssrs 101 10-0210 A Wonderful Opportamty The Bestorn Division of TOT RADIO CORPORATION OF AMXRICA accept no DOT or rnexpe- rlenssd spplleanti In their serrkes as Wireless Operators ether than ear Graduates: Invssucste tin sarantaset. af- fessd throarb. taking slthsr oar HOMB BTCDT or BJD8I- DBTNCB course to Radio, RADIO INSTITUTE OF AMERICA Formerly Marconi institute New York City RADIO PANELS Cot nut tr to atM tnd shinned wltbls 11 \L lneb thick. 1 t*e per Milan Inch. I li lnon. l>*e par sausrc Inoh. Midi of lbs hlsbeot rraa. black fibre. Trill material aSSaaafSS blth dlelootrli WILEY PANEL CO. 2321 So. Oontral Park An. Ohleeso. III. easy to HiH. Me: Si BOBBINS RADIO DESK A Place For Your Radio Set Separate arranged closed compartments (or Batteries, Head Sets, Tools, Extra Parts and other Appliancea. Useful and ornamental in any home with a receiving set. In oalt and mahog- any finish. Send for Illustrated Literature. ROBBINS WOODWORKING CO. LIBERTYVILLE, ILLINOIS Novo •ERIES NOTE THE INSULATED . BINDING POSTS AND 7m. WIRE CONNECTOR NOVO lVTF'G CO, W. ST. Wl SO, DEARBORN ST "' NEW YORK — CH.CAGO GUARANTEED REPAIRS VACUUM swBaBRwRwEw>nBBBBBeBBBBBBBBBBB TUBES i V/.D.-ll not accepted for repair Yow easier sksuM kaee. Set II tea eoss est. end direst as HARVARD RADIO ' ABORATORIRS Beaton I, Mass, turned Panel Pest RADIO WORLD rt wmntDAt Saturday ear bam wrjbjj nut roBUCAxiosf otmca. OOatPOaUnOat ROLAND BUnJtB HatMNRBBT, Pi Slim at a. _ _ rUD 8. CLAM. Bnllliry and l«tl BBOADWAT, KBW TOBJL K. T. TECHNICAL EDITOR L. SUt>SCRJPT10N i a sspy. M.08 a LiSter Baras Add tl.00 a fear eatra tor Canada 50 emu. Rasetpt br see ■■llarlai at the RADIO WORLD stalled te . Is 10.00 Net, «% 10 *% en IMPORTANT HOTICR sstaisnBs awSen*S^Mt end aSatis "'' Do Magnets Affect Tubes? There has bee* considerable mention lately in radio literature regarding the effect which a strong, permanent magnet exerts upon the action of audions. Experi- ments conducted by John Stone Stone are recorded wherein the author describes a magnetic field created in and around the tube in such a manner that the vertical axis of the magnetic field is approximately parallel to that of the filament, grid and plate elements. When the proper location of the magnetic field was found an increase in tube efficiency resulted. The presence of an electro-magnetic field is said to increase the flow of electron? from the filament through the grid, to the plate, and this increased flow means an intensification of the volume of amplification. When used on a two- or three-element detector the accelerated electron flow due to the presence of the magnet is indicated as being the means of giving the detector tube additional amplifying qualities. In whatever form the magnet is used, however, its position relative to the tube elements must be according to a definite space relationship between the filament and the poles of the magnetized cup, cylinder or other shaped mass of magnetically-charged iron. It is well known that only certain kinds of iron will retain a magnetic charge. Certain grades lose their charge almost immediately after being charged, while other alloys requiring special heat treat- ment will retain their magnetism almost indefinitely. This is an interesting field for amateur and professional experimentation, and one which will probably result in hang- ing up some new distance records in the radio hall of fame. PATENTS Phono. VsnoarkUt Till. new y:a> Large shirt msnnfaotnrer wants stoats to soil complete line of shirts, pajamu. Lend nightshirts direct to wearer. Ad V vol sited brend~«xcl naive pattoiac eair /to selL No experience or capital re- quired. Bntlrelv new proposition. Wrttm for fr— ooaipJej. He Sin. Skin Oo^SOkeVlcS.oi. B.VA RADIO MAILING LISTS 12.400 Radio Dealers, orreries U. S. ky I.SI4*Radit '■fri.' errerYss' U.S." try Stat* 1,717 Radio Seeehr Jossers, esseriao U States, sor list ISO Radio Stations, per list. 2(7 etfrs. who stake end Radio Sots, sor list 20.000 Radio AsMtsers and Mesas era of Rsdk StatJeea. sor M |7 js ser list IILM IILM .Hal Asa tor erlot jlsnj "for" OsasisL CaejasA atasr haaf* CIRCULAR ADDRESS INC CO. TRADE C 100 W. ADAMS STREET CHI0AS0. ILL CRYSTAL FANS Are you satisfied with your crystal, or do you want better results? MOLYBDIC GALENA A new detector just discovered is sensitive even when ground to dust Send 50c for one of these wonder crystals. We will refund your money if you are not entirely sat- isfied. Phoenix Radio Laboratory Box 168, Phoenix, Arizona ©'ODlrlAN I Taw Nifties* Sheet Were Ti Only BL00 A PP ssa 1 Da. • L. W. GOODMAN DREXEL HILL, PA. Is rstsstJy trltk ■ are sow 00 sjllss DENVER mas Ik aid sank tee skip. , Pa„ writes: Usees-. GOODMAN, hears t who, "*• ' Irani Ben Frsnillil," Ten Digitized by VjOVJ^LC

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RADIO WORLD DX Nite Owls {Continued from page 21) Two Interesting Logs From Robert H. Anthony. Boatoa, Maa. INASMUCH as you were kind enough to publish in a recent issue stations re- ceived with our No. 3500 Amrad radio-fre- quency outfit, I thought you might be in- terested in extracts from our log book, covering two recent evenings' reception. The logs are as follows: February 10th and 11th (10:30 p. m. to l a. m.) Havana, Cuba. Piano Solo. Los Angeles, Cal. Woman Sing- ing. Fort Worth, Texas. Speaker. Chicago, III. Davenport, la. Mississippi Syncopation. Milwaukee, Wis. Sunnyvale, Cal. Radio Shop. Singing and Orchestra. Philadelphia, Pa. Philadelphia. Pa. Chicago, III. Drake Hotel Orchestra. Spokane Gironicle, Washington. (Signed off 7:34, Pacific Coast Time.) Newark, N. J. Philadelphia, Pa. San Francisco Examiner, Cali- fornia. Music. Pittsburgh, Pa. Kansas City Star, Missouri. Jazz Orchestra. Total, 17,972 miles. Time. 2 hours 40 minutes. February 15tit, 1923 PWX KHJ WBAP KYW WOC W HAD KJJ WFI WOO WDAP KOE WOR WNAT KUO WCAE WDAF Time P. M. 8:10 Location City State Country Springfield Mass. U. S. Toronto Can. Can. New York City N. Y. U. S. Montreal Can. Can. Pittsburgh Pa. U.S. Boston Mass. U. S. Schenectady N. Y. U. S. Davenport la. U. S. Detroit Mich U. S. Dallas Tex. U.S. Atlanta Ga. U.S. Vancouver B. C. Can. Chicago 111. u. s. Louisville Ky. u. s. Toronto Can. Can. Med ford Mass. u. s. Pittsburgh Pa. u.s. Newark N. J. u. s. Havana Cuba Cuba Fort Worth Tex. U. S. Parksburg Pa. U. S. Atlanta Ga. U. S. Denver Colo. U.S. Cincinnati Ohio U.S. miles. Average 5.828 milas Call WBZ CFCF 8:10 WEAV 8:17 CHVC 8:25 KVKA 8:27 KNAC 8:29 WGY 8:30 WOC 8:31 WWJ 8:45 WFNA 8:50 WSB 8:55 CJCE 9:08 KYW 9:10 WHAS 9:17 CFCA 9:25 WGI 9:40 WCAE 9:55 WJZ 10:00 PWX 10:11 WBAP 10:20 WOAA 10:40 WGM 10:50 KLZ 10:55 WLW per hour. Time. 2 hours 45 minutes. « • * Not Claiming Special Honor From Thca Newaora. Lawton, Oklaaaaaa I AM taking the liberty of writing you in * regard to some DX records I believe to be good. However, I am not claiming spe- cial DX honors, and also am not sending a list of stations that I can't duplicate every day. Also I receive these stations on my magnanox, using a single circuit detector and two stage three to one transformers. Stations: KYW. WCX. WWJ. WDAP. WLAG. WOC, KHJ. WSB. Willi, and many other nearer stations. The above sta- tions were loud enough to he heard all over a four-room hou«e. using 90 volts B battery. * • • From Canada to Corona From T. Eiarnatein. Corona, N. Y. I AM a constant reader of the R vnio World and have read smne of the DX ^cords. I am somewhat of a "DX Nite ■VI." T have a sini. r ^t. ::-:iv a WD !I tube and have heard the following stations : Local— WEAF. WJZ, WBAY, WRW, WAAM, WOR, WHN, WBS. DX Stations — KSD, KYW, KDKA. WBZ. WDAP. WFI, WEAN, WGI, WGY. WHAZ, WOO, WSB, WWJ, WLW, WMAC, WNAC. WMAQ. WOC. WIP, WMC. WHAS, and one station in Canada CFCF. * • « Has Caught 80 Stations From Donald Crawl, Wan.traai. Waaa. I AM sending my receiving record of the past three months. WLAG. Minneapolis; WMAT, Duluth: WGF, Des Moines; WHB, WDAF. Kansas City; WBAP, Fort Worth; WFAA, Dallas; WOC, Davenport; WPAH. Waupaca, Wis.; KSD, St. Louis; WDAP, KYW, Chicago; WCX. WWJ, Detroit; WLW, Cincinnati: WCAE, KDKA, Pittsburgh; WDAJ. College Park, Ga.; WSB, Atlanta; WGY. Schenectady; WHAZ, Troy— distance, 2,30> miles; WIP, Philadelphia— distance, 2,300 miles. RADIO TUBES REPAIRED "Saaraataaa Coaal to New" FOUR DAY SERVICE • V. IKMn 11.10: AaplHWn. 12.71; ( Watt Pov Tana, 04.00 RrtlMa) Tata. Atvayi la IM Our rcpuirrd tuhrt §i>rak 1*t thrmtrlt «-«. Radio Tab* Laboratories, lac 771 Draaa) Strati Nawartt. ". | . u. S. a. Pataat Pa.*.. THE JIFFY CLIP I On In a JMfy, it daaa away wHs ten. ta-awr and mm*,. ISc, HERBERT M. HIM, Dam*. D. m FOOTE'S HAND-MADE TRIPLE-TEST CRYSTAL "Put. Its Baa, Foo» Far— oar" IU auiwraraaltlTr Ilila la op ,n.l hu Inu.Hr n*rl,*,l br«im vawaaw. 1.01 Irar Raaatr Battortaa. tt'/t V.. I"t« 100 Cnr Raaaly Battarlaa 41 V. 17) Mi.aaa VanaMa Var.iar Caa«.»..^ .0001 1% if .000* } no Ml i.71 Darf.a Ma. Wad Vui.a,m. ka.k aw.*, mo natert 7.1a Dayfaa Ma.l4*0 Variawaalan. kiaak w*ua. 1.00 Ualta. gtalaa Taal Ca. Varalar C«a. tuana t baa kroufkt la MONEY ORDER OR CERTIFIED CHECK INCLUDING POSTASE MUST ACCOMPANY ALL OAOtm SUNBEAM ELECTRIC CO. 71 THIRD AVE. (B**. Ilih and 12th RriO NEW YORK r.rra Llfhtinf Plant, at Barfain Pile... Digitized by Google

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26 RADIO WORLD Original Nathaniel Baldwin Headset* Typ* C OMIhu SHS- $11.75 m x » mv*^ i - -> FREE with tub pair of phones — l 15.00 Snsltone Loud Speak- er. Phones out bo used as brad tot or on speaksr. Both for lea Una the regular price of Um Baldwins. Cash with order or O. 0. D. WALTER SCOTT 10 St Lukee Plase Mtatelalr. W. i. gEl^CANTO B*^— . .HUM! IIiSjl ««^^ Beautiful In Design. Pur* in Tonal Qualities. No Auxiliary Batteries. Absolutely No Distortion. Disperses Sound in All Direct lone. Get* Away from the Grotesque Horn. Guaranteed for 12 Month* Against Mechanical Imperfection. Developed by an Acoustic Engineer of Recognized Ability. Endorsed by Ignace PaderewsM. Us ted at WO, F. O. B., New York Is adjusted for regenerative two stages of amplification, also five tube radio and audio frequency. Bel-Canto Corporation 417 East 34th Street, New York City LOUD SPEAKER Scientifically Perfect. Artistically Beautiful. The JOLLEY Loud 5 p e a ker Eliminates Howling and Extra Batteries, Power Am- plifiers and Adjust- ing. Just connect re- ceiver and Enjoy Perfect Radio Entertainment Written Guarantee of Satisfaction or Money Back. Type D. H. No. 1020, $35 F. O. B. New York Dealers u-rite for special trade iniosition. in' WDIO CO. New York LETTERS TO THE EDITOR A Farad Symposium EDITOR, Radio World: I note with interest the article on page 2 of Radio World, January 20 issue. It looks to me as though Mr. Godfrey does not know the physical dimensions of a condenser which would have a capacity of .001 farads. The largest size condenser — that is, variable condenser — with which I have worked in radio work had a capacity of about .01 mfd., and it had quite a few more plates than the ordinary air condensers seen in the radio supply stores. Besides it had mica between the plates, which, of course, increased the capacity, due to the fact that the dielectric constant of mica is from 4 to 8. Now Mr. Godfrey or any one else never saw a variable air condenser with a capacity of .001 farads, or any capacity anywhere near that much. I doubt if he has seen one with a capacity over .005, which is much larger than is used in any ordinary receiving set. The term .001 mfd. is correct. It is written decimally .000000001 farad. Mr. Godfrey states that if the value .00025 mfd is correct then the capacity of that condenser is only 250 millionths of a millionth of a farad, which seems rather smallish to him. It is small, but, nevertheless, it is correct. This value written decimally is .000000000250 farad, or 250 micro-farad, which is a term being used more and more by radio engi- neers, as this is about the most convenient unit to use in radio work when dealing with receiving apparatus. Then an ordinary .001 mfd. condenser would have a capacity of 1,000 micro-farad. One micro-farad would be written decimally .000000000001 farad, which would be one millionth of a millionth of a farad. I am sending this in with the hope it wiU make this matter clear to Mr. Godfrey and your other readers, as any one reading Mr. Godfrey's article who did not really know which was correct would be confused and perhaps misguided. Very truly yours, G. G. Adams. Belmar, N. J., Feb. 23, 1923. Home-Made Set Works Well EDITOR, Radio World: In a recent issue of Radio World you published a letter from Burdette Bowman in regard to results secured by him with a receiving set consisting of two home-made honeycomb coils, a variometer, 23-plate variable con- denser, rheostat, one WD- 11 tube, one phone condenser and a grid leak. Being his room- mate I made a set like it, and on the night of February 19. between 8 and 11 :55 o'clock, I caught the Kansas City Star; Atlanta, G,1. : Minneapolis, Minn.; WBAP. WGY, WMAQ. WOF; the Missouri State Prison; the Manitoba Free Press. Manitoba, Canada ; WLW. WSY and WJZ. The set is per- fectly satisfactory. Instead of an aerial I used a Ducon light socket plug. The honeycomb coils were 25 and 50 turns. I also used 22;^-volt "B" battery and one clrv cell. Yours truly, J. A. O'Neal. Marion, Ind., Feb. 23, 1923. The A. R. R. L. in Albion, Mich. 1212 Highland Avenue, Albion, Mich., February 16, 1923. Editor. Radio World : Replying to your request in your Feb- ruary 17th issue, tabulate the Albion Ra- dio Club C\kR[.). Kd. Williamso-i. president; John Brvden, vice-president; X. F. Lovah, treasurer. It is an amateur organization. Yours truly, FLOYD B. QUIGG. Secretary A. R. C. Cxseilost 43 Plate Oislisur .Ml II. 11 Cseelleat .M0S VariaMs Osage essr I. It Varlenetors. Balevlo Style. Weed I.»* Kl»a Anilities Lead Talksrs 4M Fssr-Caa-LMsa Nuhiaksass 1-SS CASH WITH OBDam Radio Engineering: Co. 2 West nth Street New York Ch> White's "Va.rl©ment" Make year «vs sella. Ooaetrsat esrieeeeters, •sealers, sts. Ms dlstjrissSJd saaasfa/. Met** lags seemly eed asrasaaeatly. Bend 25c. for eossple Aortic WHITE RADIO COMPANY lis teat lire street Mew Yen WHERE SPACE IS LIMITED The Na-ald 8eiall-space Socket is moulded from iron ulnt Condenslte. Require, but small spaas for mounting. Special slot rslnfonsmeat; virtually brsakabU. No sresss metal to Interfere with eaV eleney. Phosphor bronze eootacta. Cannot be sxTeKad by brat. Exceptional Tskie. Equal In Quality to any socket using bottom cos- tart. AttrscUrsly bar ad. Display container rarnuhsd for dealer's counter. ALDEN MFG. CO. Formerly Aldea-Naplsr Os. D.st. L, 32 WlUear Street 8 eMail* id. Experimental Wireless Stations By P. E. EOELMAN Tells how to make apparatus to not only near all telephoned and telegraphed radio messages, bnt also how to make simple equipment that works for transmission over reasonable long distances. Then there Is a host of new information included. The first and only book to give 70a sfl the recent important radio improvements, anas* of which have never before bean published 392 pages, 167 illustrations PRICE OM THE COLUMBIA PRINT 1493 Broadway, New York City AUTOMOBILE CHARTS By Victor W. r*m% ICS.s4.<f. Unlftrm 81m — 24 lu. i 38 In. — Prle* 35c Es* Late tie* of ImltUn 8yst*« Tr*ublM Matte Ea». In this chart all parts of a tyrdoal double Unl- tian tratem using battery and magneto current are shown, and guirgertlone are g\rm for nattily finding Ism Ulan trouble* and eliminate* those when round. Include* latest Deleo. Oon.wetlce* and other system*. (34 x 38.) Price, 38 Mate Lubrlcatle* of the Meter Car Chassis. This chart present* the plan -lrw of a typical six -cylinder chassis of standard dealtm and oaUlfls* all important bearing point* requiring lubrica- tion, and Is * valuable guide to the eorrest lubrioatlon of any modern ear. A practical ebart for all Interested In motor ear maintenance. (34 x 38.) Prr**. 38 ocsna While eoeh of the abev* thro* charts Is mm- Diets, the sot eevors all malRteaanee Irrstrocttoos for the entire auts mettle*. Location of Starting and Lighting System Faults, The most complete chart yet derleed. sitowing all parts of the modem automobile starting. Hcbtlng and Ignition systems. g\r\nx Instruction* for sy»- tetnatlo location of *0 fault* In wiring, lamp*, motor or Ken era tor, mitche* and ail ether unit*. Invaluable to motorists, chauffeur* and re- pairmen. Site 34 z 38 Inches. Price. 3$ cents Location of For*] Eafln* Troubles Mad* Easy. An on. anted and re-lned chart showing; clear eee- tlonal rlews depleting all portion* of the Ford row plant and auxiliary group*. It outlines elearlj aD parts of the engine, fuel *upply ays tarns. IgtUtraa group and ending system, that are apt la at** trouble, detalllnx all derangemente that are liable to make en engine lose power, start hard, of work lrronuUrly. This chart almpUflea 1 oca: toe of all engine fault*, end Include* lnptruetions for IncatltiK Foni electric startae trouble*. He* 35 i 38 Inches. prle*. 88 eMts Location sf Motorcycle Troubles Made Easy. Prle*. 35 ssabj The Six Charts Bent for 82.00 THE COLUMBIA PRINT len Broadway, New Yea* Oty Digitized by Google"

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RADIO WORLD 27 TUNE-IN ON THE NATIONAL WAVE LENGTH AND SAVE MONEY ON YOUR PURCHASES ' Lowest Prices on Standard Radio Goods in the U. 8. A. 170I7I7 A HYDROMETER (Battery Tester) with 17017 "C r I\£d JZj each purchase of $1.00 or over JT 1\ CjIL HAVE YOU ENTERED OUR ADVERTISING PRIZE CONTEST? FIRST PRIZE— $250.00 Radio Set Free— Six Tube Radio-Audio Frequency Set SECOND PRIZE— $150.00 Radio Set Free— Four Tube Set, Detector and 3 stages Amplification THIRD PRIZE- $100.00 Radio Set Free— Three Tube Set, Detector and 2 stages Amplification To advertise our business we will give the above prises to the three persons striding- us a list of five or more names of Radio fans and who compose the best slogan or phrase of words we can use for our advertising matter. We are interested in sending our catalogue and price lists to Radio fans. If you are interested in Radio and in its future possibilities don't overlook this opportunity to get acquainted with us, secure low prices on your purchases and an opportunity to win one of the above prizes free of charge. In the event of two or more persons submitting the slogan judged the best, second best, or third best, each will receive the full amount of the prize tied for. All entries must be received by us not later than March St, 1923. Our Peanut Tube Does the Work of WD-11 For Detector and Amplifying uses. Can be used on 1% volt dry cells or regular 6 volt A Batteries. Fits standard V'.T. socket. Uses about 1/10 ampere, on two 1H volt dry batteries. Price of tube, $2.50, includes adapter. V/x VOLT TUBE (not WD-11, but for same use). For detector and amplifying uses. Used on 2 Dry Cell batteries <1»/, volt) $5.00 THIS WEEK'S SPECIALS 1,000 HEADSETS, $6.00 Value $2.99 each Bi**eet Radio Bargmim Ever Woreo-Oreer Praaspllj 200 RADIOLEAN CRYSTAL SETS, $12£0 Value $6.50 each tnrhi.a. RmMh Set mad AS In Eai fciiinil VACUUM TUBES VERNIER CONDENSERS v.ZJ^2?ZZZ^£?3-yi » Lt« t »: oo., type V. T. 14. Lift SMS. maw MM » " MS. *••» U. V. 2S* Detector 4JS 41 Plate - SJS, " MS u.* v: »^AAai«aBw;;';:;":;;;;'" '.'"''.;;''.''"'"';;!; £2 rr.*w &« L~k «a c«-*«-r a. WD.ll 14 Volt US FWwrfltas Circuit " MS. " .7$ Cunningham Detector 4JS . ___________ Cunnmfham AmpUnar US TRANSFORMERS Mrere Audio Hicb-Mu 4JS y,,,,, u„ UM ^ „_„ Vacuum 'Tubes Repaired. Broken aad burned out tubas Atwater Kent " MS." - J.7S repaired. Mail mam parcel post Insured. Price, C7f Serb. „ „ cash with your order. Tubas returned by Parcel Peat, pre- Ac™* *•** paid. W* ruerantee tbam to burn equal to new tubes. WD-11 " %.m. - i ll BUSS BAR WIRE— 6 two-foot lengths $0.25 DX TRANSFORMERS, $9.00 Value, Special 6.50 HEADSETS St Ohm. equal* beet SMS phones on market, now SUS Ohm US Federal MS HOW TO ORDER Ss^Jr"™ * p~l w ^ ~Ur' iadode Um foUowimg rates with same for postage) Ob Pvrchasoe flM to S&M. • Coats Postago On Purchase* SIMS to VMS, 2* Coats Postago On Purchasaa $M» to $UM, 15 Coots Poatago On Purckaeaa SZLM to S2MS. IS Coats Postago Spaca being limited, wo are obliged to omit other mom oy- earing itoans. Write for ajwotatioaa or ask for our latoot Prico Shoot Catalog. National Radio Products Corporation Mail Order Dept., 509 FIFTH AVENUE NEW YORK Digitized by LjOO^IC

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28 RADIO WORLD WALCON Radio Frequency Transformers Brine* in distant (tattoos on a loop — perfect reproduction. No distortion. Awarded Certificata of Excellence by N. Y. Eva. MaO. THE BEST YOU CAN BUY WALCON Transformers are tested and auaranteed. Particularly adapted for use with WJ>.-11 tabes. Four new hook-ups, including a new reflex circuit furnished without charge with each transformer. Price, $4.00. We pay postage. Dealer* and /obbtri: Writ* for our attractiv* sale* proposition, bached by national adcertiting. Manufactured by THE RADIO CENTRE, 2 West Broadway, N. Y. DELICATE SOLDERING Both the problem oa ail flae wart la readily for tbii parti cmlar pen-pose. •aired by the THE POST SOLDERING IRON Platinum Heating Unit— Interchangeable Tips— Unireraal Cnrrent (Lory* ant flasail) 0NZ-HAL* ACTUAL S1ZK *L60 er Write Awarded Certileale of Fniehaij. M. T. Brenlmf Mall Radio POST ELECTRIC COMPANY, (Of. 50ft) 30 L 42nd St, New Tark RADIO SPECIALS 52-Page Catalogue and Code Card Free With Every Order. CLAPP-EASTHAM RECEIVERS TYPE HR REGENERATIVE RECEIVER $25.00 TYPE HZ TWO-STAGE AMPLIFIER $25.00 Baldwin "C Headsets SUM Baldwin "C» Units S.SS Frost 2tM ohm Headsets *.at Frost MM ohm HeadaeU $M Murdoch MM ohm Headsets SM Murdoch MM ohm Headsets SM Double Headbands .» Single Headbands St Double Phone Cords Jf C. A. Phone Condensers (.Ml) J» G. A. Grid Condensers (.MS) j» Moulded Condensers (.en) St Feeco 3 Plate Var. Cond. I. St Fesco 11 Plate Var. Cond IJS Naald 1-tn. Dials, Condensits SS WhitaU 3K-in. Dials St WhitaU Condensite Sockets St NaaW WD-11 Sockets .71 WhitaU Moulded Rotors St Federal 2 Circuit Jacks Jtt Federal Open Circuit Jacks St Federal Closed Circuit Jacks. Plugs for Tips, dy "B" " Eveready "B" Batteries , Red Seal Dry Cells for WD-11. Red Seal Sparkers for WD-11 Acme Amp. Transformers R. Corp. Amp. Transformers... R. Corp. Radio Transformers. . . Thordarson Amp. Transformers. Bradleystata Paragon Rheostat R. Corp. Rheostat R. Corp. Potentiometers WhitaU Variocouplers Paragon Galena Detectors Reinhart's Wound Coils Switch Points, per dox Switch Stops, per pair Tested Galena Woodsmetal Copper Lugs, per doz 1.7S 7M tst AM US ISt S.M 2.M Z.7S 1.M ITS .It .M .25 .11 .It WD-11 TUBES, $6.50 PROMPT SHIPMENT THE WHITALL RADIO CO. SPRINGFIELD, MASS. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City. Pltast send me RADIO WORLD for months, far which please find enclosed $ SUBSCRIPTION RATES: aukCw 4. IS Three Months LS0 Si, X'^.tbs J.00 r (SI Issaet) 6.00 Year for Foreign r Canadian Post- Milwaukee Amateurs' Radio Club THE design and construction of station 9AAP, Milwaukee's only station to have its signals span the Atlantic, was the sub- ject of a paper presented at the Milwaukee Amateurs' Radio Club's first meeting in February by Marian Szukalski, Jr. E. G. Nickel and E. A. Cary, both of 9ATO and members of the club's publications commit- tee, have given digests of current radio liter- ature in their reports. The topic of one of the most interesting of these was station 6KA, its design and records. District Superintendent C. N. Crapo an- nounced in his monthly report that Milwau- kee County, the smallest of the districts, with 415 messages handled, ranked second in the race among A. R. R. L. traffic dis- tricts of the state. A silver cup, known as the Wisconsin Cup, has been offered by B. A. Ott, assistant division manager in charge of the state, to the stations which monthly handle the greatest amount of traffic. Members of the Milwaukee Club are now out for this honor. City Manager I. H. Strassman, 9AHO, announced the presence of several unlicensed stations in the air and that he and his staff were taking steps to clear up the situation. Incorporation of the Club under the laws of Wisconsin has been assigned to Attorney L. J. Topolinski, the society's general coun- sel. Business Manager L. S. Baird has opened negotiations with the South Side Radio Club and the West Allis Radio Club with the idea of bringing about consolida- tion with the Milwaukee club at the time of incorporation and forming one large county association. Solid Wire Favored Over Litzendraht T ITZENDRAHT WIRE, which is a * special cable consisting of a number of strands of fine insulated wire, has long held the reputation of giving lower losses with radio-frequency currents than any other type of wire. In most cases coils of high- grade Litzendraht may show a 5 to 50 per cent, decrease in resistance compared to solid wire, if all the strands are perfect. On test, according to the New York Globe, it has been found that a coil employing Litzendraht may act perfectly for six months or a year and then develop troubles which indicate a broken strand. This often occurs no matter how carefully the coils are manufactured, mounted and tested, although it does not make the set inopera- tive, and would pass unnoticed by many users. Even with this drawback Litzendraht is' the superior of the two. Actual tests have shown apparently no difference so far as sharpness of tuning is concerned or -for its qualities in an oscillating circuit. But the desire to safeguard users from the freakish effects of broken strands is enough to throw the balance in favor of the solid wire. Information for Sea-Going Radio Operators READERS of Radio World who are de- sirous of securing information as to the proper procedure to follow in applying for positions as radio operators on American merchant vessels are invited to address Mr. Claude Cathcart Levin, associate editor. The American Officer, 37 Maiden Lane, New York City. Mr. Levin has very kindlv of- fered to answer questions along these lines from Radio World readers who will enclose a self -addressed and stamped envelope. Mr. Levin served during the war as a commis- sioned officer in the Navy and holds both radio operator's and marine engineer's licenses. He is qualified to answer question? regarding the service. regarding tne service. Digitized by VjOO^IC

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RADIO WORLD 29 UNO MB TOtTE PHONaa) far ra»aira. All makaa. luruU*i ImmMIi eharaaa. Bar, in Waa* 1M as. Vow Ta CABINETS Hla«ad Tap, BaauttfaDr 1 Maboaaay Famiah. 7»1S tSJS Tan .. 7x24 S4JS A»* yow daojar /or (Aa B.C. Tyf. R. C. MILLS MS Fourth Avanua Naw York City "The Little Wonder" FOR BOYS AND GIRLS ' CRYSTAL SETS t/i mblmd-Nt Catches distinctly everything broad- casted within 30 miles. We also manufacture the "Little Wonder" assembled set at 96.00. GUARANTEED TESTED CRYSTALS Galena 15c Radiosite 20c Write for Free Catalog; It Mats ail ear radio parte aa4 Holloway Elec Supply Co. Inc. 238 Third Are. New York City CUT RATE RADIO Every article told on a written Money Back Guarantee A Few of Many Specials Hydrometer, accurate 32c 7x18 Cabinet, Mahogany, hinged top *2.6» 7x18 Panel, high finish 91.79 Rheostat with Dial, 6 ohms Rheostat, tapered knob 44c 3 Plate Vernier Condenser 7»c 11 Plate Variable Condenser 89c 23 Plate Variable Condenser $1.09 Variable Grid Leake, % to 3H..43c Shielded A-A Transformer, 10-1 or 3-1 ratio $3.69 Marie Transformer $2.89 22 '4 Volt Variable Battery 79c Write for Catalog. Unclose Money Order for at least 2Scfc when ordering. Balance C. O. D. THE RADIO SHACK 338 W. 42nd St. New York Farmers Benefit Greatly by Radio Service A CCORDING to a survey recently con- 1 1 ducted by the United States Depart- ment of Agriculture radio market news is proving of national practical use. Nearly 50 per cent, of the hundreds of returns to an inquiry sent out by radio were from farmers who had radio-receiving equipment. The remainder were from grain dealers, mills, elevators, banks, telephone companies, co-operative organizations, farm bureaus, and other agencies which disseminate the reports among large groups of farmers. Greatest interest was shown in the grain market reports, which inform farmers of wheat, corn and oats prices at the leading grain markets. Next in importance came the live-stock reports of prices and move- ments at the principal live-stock markets of the country. The weather reports came next, followed by reports on poultry prod- ucts, fruits and vegetables, dairy products, hay, cotton, and other farm crops. Radio has developed more rapidly in the Middle West in the corn, wheat and live- stock growing regions than in other farm sections of the country, the survey shows. Missouri, Illinois and Iowa lead in number of responses to the survey. Many fanners in this territory own radio equipment and praise thc_ practical value of the service. In other sections farmers congregate at central points to get the reports, but an increasing disposition toward installation of sets for private use is indicated. This was the first survey made by the department to determine how widely its radio market reports are being received and used by farmers, and afforded much valuable information for developing the service to the maximum of efficiency. It had been known in a general way that the service has been of value to producers and other agri- cultural interests in the marketing of crops and to consumers through the regulating of market supplies, but definite data were not available until developed by this survey. The department practically covers the country with its radio market news, and farmers everywhere are using the service to aid them in conducting the business end of their industry. In the replies received, numerous farmers gave instances of specific savings resulting from use of the informa- tion, one farmer declaring radio as a "direct (lift from God." Numerous general stores and banks in small towns say that estab- lishment of their places of business as a central point for receiving the reports has resulted in tremendously increased business in many directions. Prospects Good for New Radio Stations TTllKRE arc good prospects this year of a number of pood stations being erected in parts of the country not now supplied with satisfactory broadcasting service. Outside of the more populate'! centers there are few really powerful stations, although there are many small ones with from twenty to forty watts of power in the antenna. These are obviously insufficient to supply service even to re- ceivers close by. except to really good sets, which in any event can pick up the more distant station' It «i|| I*. a great dav for radio, says the New York C!,->he. when every tulie set in the country at le .st will be in ranee of a first-class broadcasting station, an. I. in addition. can pick up at will the next l>e>t station. Vaudeville Stars on Radio BLOSSOM SIT I. FY and her commnv and Georse Rockwell and A I Fox, while playine the Davis Theatre in Pitts- burgh recently. I.r-.idia-t parts of their acts from station KI'KA. IVt-hureh Port National Radio Service Co" 14* W. 32nd St. Now York. N. Y. 'Flachar Variocouptar (Small) SL1S FlacW Varan oiajhi (Largo) US Fiachar VariaaMter (Sate!) LIS FlacW Vaikauaf (Larva) US Arrow Variocouptar LIS Arrow Vartonotar (SaaaB) LIS Arrow Varionatar (Laraa) US As. CO Plata Coadaaaar IM A B. C a Plate Coadaaaar LSI Fraatmaa Var. Grid Laak and Cad... .7* Fraahiaaa Var. Grid Laak M Da Foraat Rhaoatat M TRANSFORMERS Acme (Audio).. S4.25 Kaala ( Audio) . .ti.95 Acme (Ra.lio). 4.2S Ra.la (Radio).. 5.95 Marie (Audio).. 3.45 W.D.12 (Audio) 4.2S General Radio.. 5.00 Socoatat (Sockat aad Bhaaatal Caaa- Dr. Satht Phoaaa S.TS Fadaral Phoaaa US Four War Pk*S LIS Fink Bull Dot Ptaa 3* Fraaahajhaai Rhaoatat (Plain) JS Fraaaiaakaaa Rhaoatat (Varalar) LB Caaaral Radio Aaaaofraar Uaat far W.O. U Tuhaa 74S Caaaral Radh> Aaapafrtm* Uatt far U. V. Tuhaa (ja ALL TARTS FOR LATEST CIRCUITS UKE FLEWELLIHG AND REFLEX WE PAY THE POSTAGE EAST OF MISSISSIPPI RADIO LOID SPEAKER FOR PHONOGRAPHS T».«- VfiRRIMW L#-u 1 ftr-'aklflf fi.tl. for u*# on ;•!.« s.rsi+j laAra • (,«• i.'ar* -t |ai| h-» ina-ts 1' —*..«* a U*ir ;s rm lonr-irTTi of In |>ltr* of r» .'»!.»». or rid t U««t atlth tv"' A ■ t* 1 ^ J la ar » bal' »1 » ih .»r# i» fix* a • !,-•« of tin: "irra. *. •n \ l.tjouhl* ffi-m tcfX Ia \, j. ] •*>-* Can-iaf ratti* of |»ari| thr.-u'h m*1ro>,| llflu l tjiat ~- .a*r*j wilti i sti'Mlts lr.atrytr»'.ia «n th» •r ft ■ • TV mv» r 1* lr u** t i.I.t > tit* I M* s - fi Mot liar, i-t- ,\j r.Je*-I [ it».l. f «• > ajf >I>II *f !--«■« t*"' y O If. If .l#«lr»l r-j :? fun 1 II art' T tkVI If o.-.,1*.! C Wbrc •l" If tnait at ishon«crmp*ii. MOMttOM MOM LAtMATOMO Oral II. Lrali a 1x4 OrmiL Mxa. Book on CdWabtry Br aantoxTJ rnxnn TAim TW traaMta tarn all lh> mmuIi cfm'ral «rwj *!'i-ro /NfTl'ml arrrrll Tka Calaakla mat Kit a>aa*aar. DiyiliiHd by " ^

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30 RADIO WORLD DO YOU WANT TO BUT. SELL OK EXCHANGE RADIO OR OTHER GOOD ST DEPARTMENT AT U A WORD TRY THIS RADIO WORLD'S PCK-ACTION CLASSIFIED ADS Thii department ii intended for everybody who wants quick action on short aanonncemeatt corering the boytac exchanging or general merchandising in the radio field. Reader* of RADIO WORLD will find that it pays to read thoae cot—a i every week Advertisers will get a ten-day ferric* here that is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy reaches as. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is Sc. per word (minimum of 10 words, Including address), 10% discount for 4 cooaaratrrs insertions, 15% for 13 consecutive insertions (3 months). Changes win be mads in standing classified ads. if copy is received at this office tea days before publication, RADIO WORLD CO, 1493 Broadway. N. Y. C (Phone, Bryant 4796). RADIOPHONO Adapter— Your Edison, Bruns- wick Victrola or other talking machine hat the finest acoustic properties possible. Radiophono Adapter enables you to use it as a loud speaker. Patent (Pend.) Molded Construction. Sent on money back guarantee. At your dealers or direct from us. $2.00 post prepaid. Industrial Sales Engineering Co., 671 Broad St.. Newark, N. J. HIGH GRADE ENGRAVING done on your radio panels at reasonable prices. T. Johnson, IS Rosemont Rd., Worcester, Mass. PHONES, TRANSFORMERS REWOUND. L. Werts, 409 St. Julian St., Pekin, 111 SELL— Regenerative set (unwired). $8.00 with circuit. CARL MASSON, 76 Boylston St., Jamaica Plain, Mass. VARIABLE CONDENSERS at factory prices. 3 plate. $1.05; 11 plate. SV35: 21 plate, $1.60: 43 plate. $2.05. Send cash with order. GREEN- LEAF. 34 Merchants' Row, Boston, Mass. VERNIER VARIABLE CONDENSERS— Ca- ■acity, .0006. $1.48 postpaid. Fully guaranteed, lerpeck Company, 3123 Davlin Court, Chicago. RECEIVING SET, SIS-SS. Loose Coupler, $4.00; Battery, $7.00. Mele, 39 Foxon, East Haven, Conn. RJ-MAGNAVOX— BRAND NEW. First $30 takes it. Ted Boston, Marion, Kentucky. PHONES, TRANSFORMERS REWOUND— L. WERTS, 409 St. Julian St., Pekin, III RJ-MAGNAVOX— BRAND NEW— First $30.00 takes it. TED BOSTON, Marion, Ky. VARIOMETERS, $1.50 each. These arc regular 4«-inch square variometers. Couplers, $1.00 each. Both usually sell at three times the price. THE RADIO SHOP, 261 East Broadway, Mdford, Conn. 5UPER-SIMPLCITY CIRCUIT Hear Europe, Asia, Africa and Australia's long wave stations and LOCAL broadcasting, on ONE TUBE, one control. NO rheostats, storage bat- tery, Tariocoupleri, variometers, three- coil mounting, variable inductance, taps, switches, dead end losses or radio frequency. Cats, hookup, everything. Nothing to guess about. Price $1.00. RADIO EXPERIMENTAL LABORATORY, Boa 194A, Berkeley. California. EXCHANGE LETTERS with friends every- where. Pleasant pastime. Information for stamp. Smith, Box 312S, M. Portland, Ore. VACUUM TUBE RESULTS WITH A CRY- STAL SET1 Cover distance with a "PT" ULTRA- SENSITIVE CONTACT in your crystal detect- or. Beats gold and other ordinary cat whiskers. DOES NOT JAR OUT. Myrle Wood, Rhinelend- er, Wisconsin, writes: "That Vr Ultra-Sansf- five Crystal Detector Contact I purchased la sure a wonder. Using the 'PT* contact and galena, I have beard over 41 different broadcast- ing stations, up to l.HM miles distant.'' The "PT" has received code 3300 miles. Price, only \twenty-five cents. "PT" CRYSTAL CONTACT COMPANY, Box 1641, Boston. AMATEURS— LOOK 1 Send in 15 . cents to RADIO WORLD for issue of January 30 con- taining panel layout, hookup ana full explanatory data on the construction Vf a D-X receiver, which simply lays the long distance on your table. Or start your sub. with that isssue. RADIO WORLD, 1493 Broadway, New York City. STANDARD ELECTRICAL DICTIONARY— By Prof. T. O* Con or Shane. Just issued an en- tirely new edition brought up to date and greatly enlarged— as a reference book this work is Beyond comparison, as it contains over 700 pages, nearly 500 illustrations, and definitions of about 6,000 distinct w terras and phrases. The defini- tions »•■ '■' concise and include every terra science. 7sT p sails. 477 ill' e 18 for fuller description.) P ibia Print, 1493 Broadway, RADIO TUNING RODS (Patent Applied for) Eliminates body capacity when tuning hv With Tuning Rod In your hand yon caa atop unnecessary noises -sad shrieking. Every radio fan should have Radio Tuning Rod. Bend U cents stamps or money order. Radiophone Co., 505 Fifth Avenue, New York City. TWO one stage amplifiers, Acme, $8; Rentier, $7. King Amplifying horn, $7. Condensers. J. B. Rich, Hobart. New York. THE IDEAL RECEIVER tunes with SINGLE CONTROL. No variometers, variocouplcrs. taps or switches. Cheapest to build. Particulars. ROKAY ELECTRIC COMPANY, Ingomar, Ohio. lull-page draw- ntrol rheostats, CASH FOIt OLD GOLD, Platinum, Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth, Magnate Maes, Jobs, Aay Valuables. Mail ia today. Cash sent, return asaiL Goods relumed in ten days if you're not satisfied. OHIO SMELTING CO., W Hip- podrome Bldg., Cleveland, Ohio. DO YOU WANT TO SAVE MONEY in making your set? Send for the Jan. 27 issue of RADIO WORLD, containing a full-] ing of how to make filament conti as well as an easily understandable text, which makes the construction easy. 15c a copy, or start your subscription with this issue. RADIO WORLD. 1493 Broadway, New York. OLD MONEY WANTED— $2.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave. 83, Le Roy, N. Y. RAND-McNALLY RADIO MAP OF UNITED STATES— Is 28 x 30 inches in size. The locations of broadcasting stations are shown by distinc- tive symbols. The call letters of each station are given, also the wave lengths of each. The Radio Districts with numbers are shown in red and the Radio Relay Divisions are in blue. Time zones are included. Alphabetical lists of stations and alphabetical lists of call letters are in the margins. Convenient pocket form with cover. Price, 35c The Columbia Print, 1499 Broadway, New York City. MODEL MAKING— By Raymond Francis Yates. A new book for the mechanic and model seeker. This is the first book of its kind to be pnbHahed in this country, and all these fast* rested In model engineering should have a copy. The first eight chapters are devoted to such subjects aa Silver Soldering, Heat Treatment of Steel, Lathe Work, Pattern Making, Grinding, etc The remaining twenty-four chapters describe the coa* traction of various models such as rapid fire naval guns, speed boats, model steam engines, turbines, etc. 400 pages. 301 Oluatrationa. Price, $3.00. The Columbia Print, 1493 Broadway, New York City. TWENTIETH CENTURY BOOK OF RECIPES. FORMULAS AND PROCESSES— Edited by Card oer D. Hiscox. This book of 800 pages is the most complete book of recipes ever pubHshed, giving thousands of recipes for the manufacture of vale- able articles for every day use. Hints, helps practical ideas and secret processes are revealed within its pages. It covers every branch of the useful arts and tells thousands of ways of making money and is just the book everyone should have at his command. The pages are filled with mat- ters of intense interest and immeasurable prac- tical value to the photographer, the perfumer, the painter, the manufacturer of glues, pastes, cements and mucilages, the physician, the drug gist, the electrician, tne dentist, the engineer, the foundryman, the machinist, the potter, the tanner, the confectioner, the chiropodist, the man ufacturer of chemical novelties and toilet prep- arations, the dyer, the elect roplater, the enasaeser the engraver, the glass worker, the gold-beater, the watchmaker, the jeweler, the ink manufac- turer, the optician, the farmer, the dairyman, the paper maker, the metal worker, the soap maker and the technologist in general. A book to which you may turn with confidence that you will find what you are looking for. A mine of information up-to-date In every respect. Contains an fan mense number of formulas that everyone ought to have that are not found in any other work New edition. 807 octavo pages. Cloth binding Price. $4.00. The Columbia Print, 1493 Broadway. New York City. BATTERIES— Edison Storage **B" Battery Elements, 5c per pair; 18 will make one 2X5 volt Battery. OILMAN'S BATTERY SHOP. Chelsea, Sq., Chelsea, Mass. HOW TO REPAIR Vacuum Tubes. Cocanietr literature, $1.00. Box 103, Station C, Toledo, Ohio. RADIO-APPLAUSE Post Cards. Encouragt broadcasting by such acknowledgment. 2 dozes. 25c, postpaid. D. J. SPANGLER, Elkhart, lad. GUARANTEES Radio "A" Batteries, 40 am- pere hours, $12.00. 4" hard fibre tubing, 30c per foot. Variocouplcrs, $2.25. RADIO ASSEMBLY. 1109 Valley St., Joplin, Mo. EXCHANGE JOLLY. INTERESTING LET- TERS through our club. Stamp appreciated. Betty Lee, Inc., 4254 Broadway, New York Cty 4 INCH HARD FIBER RADIO TUBING, any length to 4 ft., 20c per ft. Variocouplcrs, $2-21 Radio Assembly, 1109 Valley St.. Joplin, Mo. AGENTS— Are you interested in radio? If ss drop us a card. We have a proposition no Ere agent should turn down. Meets the needs of 90 per cent, of the public. THE WTLKENDA CO., 500 Fifth Avenue, New York City. Drpt R.W. PATENTS PROCURED AND TRADE MARKS REGISTERED— Advice and terms upon, request Robb, Robb & Hill, 1403 Hanna Bid*-, Cleve- land, Ohio; 942 McLacblan Bldg., Washington. D. C. NEWS AND GOSSIP OF THE STAGE— Send 10c. for specimen copy of the NEW YORK STAR, the great illustrated theatrical weekly. $UP year, $2.00 six months, $1.00 three months. New York Star Co.. 1493 Broadway, N. Y. IF YOU ARE A REGULAR RADIO fan and like to hear the stations in the four corners of the United States come in with a bang, then you will want the Flewellitur Circuit. E you do, send 15c for RADIO WORLD, issue of Feb. 27, which contains complete description and directions for the manipulation of the cir- cuit. RADIO WORLD, 1493 Broadway, New York. ATTENTION, Amateurs!) Have you seen tht RADIO WORLD'S page of hook-ups ia the Oct, 21 issuer 15c a copy or start yotrr with that Number. Many people an for. the hook-ups Bated here. RADIO WORLD, leM BrWwmy. Mow Yarfc Oty ADVERTISING SOLICITORS to represent RADIO WORLD. The best quick action rams advertising medium. State territory you caa cover. Tell us about your past experience. Write Fred S. Clark, Manager, RADIO WORLD. 1493 Broadway, New York. WIRING A HOUSE. By Herbert Vntt. a bouse already built; tells just ssv to start about wiring it; where to begin; what wire Is use; how to rua it according to insurance rules; is fact, just the Information you need. Dttwctassss ap- " » ahap. Santa edition. COLUM- 1498 Broadway, K. Y. C tact, just toe ti A COURSE IN MECHANICAL DRAWING— By Louis Rouilhon. The author has written a most practical book on the subject of *f— *.-*.«] Drafting. It fully explains the art of Drawing, Lettering and Dimensioning. It ia, by far, the most practical book ever published on this sub- ject, for use in day and evening schools, sad more especially adapted for the teaches and far *'f instruction. Fifteenth edition, revised sad enlarged. Full; PRINT, fl^road^y^N. Y*^ HOW TO BECOME A SUCCESSFUL ELEC- TRICIAN—By Prof. T. O" Conor Sonne. An ia- teresting book from cover to cover. TeDing ia simplest language the surest and easiest way to become s successful electrician. The studies to bo followed, methods of work, field of ope rinse and the requirements of the successful electridaa sre pointed out and fully explained. 202 past*. Illustrated. Nineteenth revised edition. Cloth Price, $1.50. The Columbia Print. 1493 Broadway. New York City Digitized by Google

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RADIO WORLD fiALENA CRYSTAL aaoated la c^il mpwd aetal Me. B— Mve is guaran- tied bth /'v tin- manufacturer annly copies sent out by the publish- es are to fill the ever-increasing >rders of the American News Com- >any, the large numbers of subscrip- ion orders received at the office of mblication, and one voucher copy to ach advertiser and advertising agent epresented in current issues. \aiuo World, 1493 Broadway, N. Y.' Howls from a Loud Speaker NOW, if I were you, I would put an- other step on there and then you would hear everything." • • • "Say, you are doing that all wrong I Don't you know that if you tune your set that way, you can't get any results?" • • • "If I were the president of the RC, I would sell the tubes for cost, just to popu- larize them. Who wants to pay that price for them ? It's ridiculous !" • * • " now as I was saying, just as I got KJH in nice and loud, I hear a terrible generator hum, and who do you think it was? You'd never guess I It was SPC down in South America. That's some little circuit I am using. No, I won't give it to you— I'm going to patent it first." • • • "So I sez to him, 'What do you think you're doing, putting up an aerial right over mine ? Don't you realize that you won't be able to receive anything? I'll get it first and you won't get any,' and he turns around and looks at me and takes the wire down." RADIPHONO ADAPTER |24>0 Church Broadcasting A SURVEY made by the National Cham- ber of Commerce develops the fact that there are eighty-three radiophone stations in this country broadcasting religious services. It is estimated that the territory covered represents about 652 per cent of the total area of the United States. jJ'AYNXQkj Tl \ * . . . ■ . , ■ L- i ' i A - T«t VACUUM 1 HHtS US.1 HIVAL Reflex aad R.F. CrretaJa APt-mrrd or radio nr-erta. Toe eery best eryi- tal known U) radio arlrr^r Will make y ur act ecund like Boon's Bind. Pre* — Reflri end sui*-r cntial r«'l»ittc sr>l in tlir>.na Inf.irmstu*. eM no* up miti r*/h en«ta] JAYNXON LABORATORY 57 OCV STRCCT NEW YORK. N. V. Anwri-Sii Mil Stores BACK MOUNTING INDUCTANCE switch, turn TUBE SET I Rbanlat I W. 0. II aaeket I W. 0. II Tea. I end Leak Ceadeeesr I •artery. 22',, verts I "A" Battery, dry nil I Varienadar I "21" Plate Caadiaaar Win ler Heat Up Free I Paael. rutl*'. MMk-U* Oaly fir Ccaaalcta. . . Spider Web lnctuctaaca Coil for lUaeiaaarta Timer, SZ.M e-aca American Radio Store* 23S Fulton Strewt, Now York City All eraen a est laelade eeetsee aad all ekecka aust be eertiarf .T.."!*..!*.....$15i§£ DUALITY Standard Radioes AJl Goods New, in Original Packages SEND FOR OUR 72 PAGE RADIO CATALOGUE WE GUARANTEE A SAVING OF 15% Rrlt-ib.e m«< handise first, then prtc*. We will refund, at any tin-*, for Hmdio mat ten aI pure h.i*-?d from us %»hir b is not up to stand »rd and as i^rrt*ntordL No Check*. N- C. O. D. Add Parcel Poet. RHrrescs: Rstdio World. 577 MYRTLE AVENUE. Phon* Proopect 2952-8168. BROOKLYN, N. Y.

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RADIO WORLD YOU NEED THESE PARTS! Designed by the S*me Radio Engineers Who Designed Much of the United States Navy Radio Apparatus. Built with Micrometer Precision Throughout You Get Remarkable Adjust men! and Avoid Dielectric Lone* with this GENUINE BAKELITE VARIO COUPLER $2.25 («- 13. «lrh 4M) This is a remarkable in- strument and a remark- able value. Accurately calculated. Micrometer precision. Made of natural UNDYED bakelite. Avoids di- electric losses due to coloring materials. Special 2 to 1 rotor movement. 180° on dial turns, 90* on rotor. Very delicate adjustments. Made for table or panel mounting. New RHEOSTAT Every radio enthu- siast wants one of these. NEVER over-heats because it has a porcelain base. Suitable to table or pa n e I mounting. 50c IMPROVED JACKS Open Circuit 25c. Closed Circuit 35c. Double Circuit 45c. L Increase Your Vacuum Tube Sensi- tivity 25% With This New TUBE SENSITIZER $1.50 v _ — A recent editorial in a radio journal states, "The placing of a strong magnet in a certain space relationship to the vacuum tube often gives an increase in tube effici- ency of 2S%." The Dyna Tube Sensitizer serves 2 purposes: First, as a powerful permanent magnet, the electro-magnetic field existing between its North and South poles tends to increase the flow of electrons from the plate to the fila- ment, thereby increasing tube power. Second, it acts as a shield which prevents electro static coupling with other elements in the set, also tending to eliminate stray capacity effects. MADE* OF SPECIAL PERMANENT MAG- VETISM-RETAINING ALLOY. FOR LONG OR SHORT DISTANCE WORK YOU CAN- NOT AFFORD TO BE WITHOUT IT. RADIO RECEIVER, Model 235, with power amplifier combined in one cabinet, jHy%p* as illustrated. Without equipment or horn List. «r*V*J Power Loud Speaker, extfa $25 COMPLETE RADIO RECEIVER SET, with full installation equipment, including vacuum tubes, batteries, com pic t e * ten n telephone headset, telephone plii(T and horn. Free installation within 50 miles of New York... a equipment. $150 SET AS ILLUSTRATED A Super-Sensitive, Complete CRYSTAL DETECTOR 75c Includes triple-tested, guar- anteed, million-point syn- thetic crystal. Base is of polished Bakelite arranged for table or panel mounting. Note new sensitive spring contact for delicate ad- justment. Guaranteed Super-Sensitive CRYSTAL Triple-tested Galena Radio Crystal. Absolutely Guaran- teed Sensitive. Set in special mounting. Sealed in 0/\-» wooden box *ivC i Thii let U un- doubtedly the peer of then all. W e hare re- ceive i eatno- •iastic reporli from every own- MODEL Z3S PARTS SENT POSTPAID ON RECEIPT OF CHECK OR MONEY ORDER. USE REGISTERED MAIL DYNA RADIO CO. DEALERS WRITE Have Your Old Dead Phone* Re-Magnetiaed 50c. or Taken in Exchange. New York Distributor* of Freed- Eisemann and Other Standard Radio Apparatus N. E. Cor. Fourth Ave. at 20th St. Telephone : Gi amercy 4M8 New York, N. Y. Digitized by Google

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15c. a Copy March 17 $6.00 a Year SI Numbers PHOTOGRAPHS SUCCESSFULLY TRANSMITTED BY RADIO Photos) While will photographs over land wim bu Un acceaa aliened Mid has been done tar some H»l, A* Ant photograph to he M and received successfully by radio was tranamittad from Washington, D. C, to the Emin| Bulletin, Philadelphia. March S, US, a distance at IM m*Ut Mr. C Fraocia Jenkins, of Washington, la the inventor of the appara tu» used. Tha principU of tba Invention is to transform the H(ht Impulses or vavn from the photographs into electrical impuWe by means of apacial glass diaca and light ceue. and then to chance them from eWx trical imawl.es to radio wave*, la the reception of the photograph the pioceee la reversed, the wivn being received as radio Impulses, tranamutad Into electrical impulse, which actuate Hght ceDa and by hhju of the discs aeon In the flluatratjon above being Impreaaed on a serjaitixed Aim aa a photographic negative. The photograph via received null be developed In the usual way. Some photographic detail was loot in the experiment due to ouf.ide interference which was not controllable at either the receiving or transmitting stations. These interfering impulses in the form of static, or sirneis from other stations, went through the spparatua and registered, thus causing the loss of detail. The pictures transmitted were those of President Harding. Vice-President Cooudgs and Governor Pine hot. all of them being successfully received.

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RADIO WORLD UtolOACRE .Radio Farms $OYVPer rAcre fl root cot load offer of the day, directly adjoining World'! Oreateet Radio Station of The Radio Corporation of America at Millar1! Flan, North Shore at Lou Island, la famoue fruit and trek tardan section. Theea fartlla tana Plata. 60 to 100 fait abora aaa 1ml. par- fast far thicker*, fruit and TegeUblee. On!/ one and a quarter ml lee from a delightful beach: superb boat Inc. bathing, fleeing- Uoeurpeoeed rar cummer bungalow eamp el tea. New State con- crete highway ■ peeing property dtreet to 59th Street. New Tor*. Beel eat of eaay tarns. Title* guaranteed. Write for Badlo farm Facta. O. L. Schwencke Land Co. »75 BROADWAY, NEW YORK Established 25 year*. Radio Distributing A Auto Supply Co- of 64 Wert 66th Street RADIO DISTRIBUTING & ELECTRIC CO. 1 Park Place New York City Phonal Barclay m Biff Special* In Next Issue 81X REASONS WHY A "Vac-Shields" 1— Non-Msgnetie. 2 — Prerents Inter- stage Coupling. 3 — Stops Howling*. 4— Prolongs Life of Filaments. 5— Tunes In DX. 6 — Protects Tabes. Attached In a Minute. Order today. Patent Peadlai Will thip immediately by mail postpaid on receipt of $1.00. Satisfaction or money back. ORANGE RESEARCH LAB. 41 North Uth Street Eaat Orang-a, N. J. The PERFECT RECEIVER One Tube Reflex Eadersad ay the New Vert Cvealat Mall Brings in DX Complete Make One Tube Do the Work of Two PARTS CONSIST OF THE FOLLOWING: One Super Sana! tire Crystal One Crystal Detector One WD-11 VT Socket 2S Feet of Buss Wire Oca 7x14x3/11 Formica Panel (DrtaacT) Eight Marked Binding- Posts Two 3-In. Patba Diale 14 Switch Polata 1 Switch Loire ra Four Stop* Ore* Rheostat One Double Circuit Jack One DL Honeycomb Cotl No. ft One 41 Plata Condanaar 18* Dorrs* VawiocoupWr One Audio Transformer Two .« Total $17.50 MAIL ORDERS ARE OUR SPECIALTY American Radio Stores 235 Fulton Street, New York City All erdera reurt Include poetago, aad all checks nuct be certified. Subscribe for Radio World, $6.00 a year, $3.00 six months, $1.50 three months. GRID THE MOST ECONOMICAL TUBE MADE TUBES 1 X Copyrighted PLATE IS NOW AVAILABLE 3 Volt Dry Cell Tube, 22»/2 B Battery, Amperage .15 $2.50 Adapters for Standard Sockets Dealers, Jobbers and Distributors write for quantity discounts DELTA MIDGET TUBE CO. NEWARK, N. J. U. S. Pat. Office 211 MARKET STREET If you can't get them from your dealer, write us direct AMATEUR*. MUD FOR OATAUSUt rate Test last Far Fan Yen af ***V "**X. RADIO IQUIPMEMT MFR. OS. MB," IMS Jereete An.. Haw York, «. T. MAIL ORDER SPECIALS Maided Ceadeaeor I Jl Daalex Phase Oliee, t for 47 Nath. Bole* la Type "C" Pheeas Ml HPMO0 Special WO-II Trmaofonscr 2JI II Plata Variable Caadsaaar. Red Mesial Cade 114 21 Plata Oeadeaeer 144 43 Plats Ceadeaocr 1.71 J- Melded Dial M HEDDEN PLACE MACHINE CO. Maasfaeturan of HPMCO WIRELESS PASTS 40 HEDDEN PLACE CAST ORANSE. R. J. The dials with absorption lasses reduced to s Mlnimnra Specialty deatgned enwe-eecuon liioaiai aliitaco loos. Bnamal, graduation and nniahcrc are ranka- larly dear. . Knob so abapad that fingers as act h- terfcrc with eaay, aoaorats reading Na-ald dials are moulded frees _ material. Rheostat boat win net effect l^jMCH DIAL Sis rbaMattl S-lneh dial far rtaootat snUssaSsr ess. far Utaraan Aid en Mannfacturlaf Co. rsrsMrly Aldsa Waaler Cescarj U Willow St.. Serta Oast, U A-AJ-D RADIO FOR PHONOGRAPHS The ItOBBISON Land Speaking Unit, far em i phonographs, takee the pleae of awkward henwa Poeoceeec a tone lalue 100% trae— en echucana never before attained in a lend speaker AtlMkot in Plaee of fepreta* 8Upa on teae-arm of pngtnoer, or eon be u any bulb net with one pbonagraph la place at te scd with hem. Adopted a or aare atagoe at aaujUcc- oon. jwaewne i™o Baft to lend tone. Case* pooalbty rattle or leoaan through easoajlre oas*- neatlon. A papular-prloed land Speekcr O* coarparea with moot arpanalTO Instruments ca B» market. Thouaanda In use. siring perfect »cB> faction. EandaDDMly alekel plated, ojeua. with 5 ft. eord. S10— at year dealer-! or area. Bent 0. O. ».. If deelred. Fully gsanmtjod Honey back if not aauened. (Whoa crdcrla epeeify make of phonograph). MORRISON RADIO UBORATOMB Dept. II. Lewie Bleak Detroit Ra*. How to Make Commercial Type Radio Apparatus By M. B. RUBPSR Tats book dascrtbss is awSsil ssaay esa- merest! types wf spark and rsssssi row telephone transmittiaf aad »eiegT»pa i" test racetrinf esjaifssssat at tu ph*S— S a. a «vu w suaf «->w, — jr*— . » — ' The earpcritBcntcr srill be a ale as n» world el ideas lor the demifB aad ease trac- tion of hla next piece of radio 8,*ir!* „ franc the rrry clear dsscriptiseei issi tars clearly Olaatrated nfnrcs .PRICE 7X- CT Any of Those Books Seat Prepaid on Receipt of Pries. Digitized by THE COLUMBIA PRINT ROOM B» 1493 BROADWAY, NEW YORK Google

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VOLUME TWO OF RADIO WORLD [Entered •■ second-class matter, March 28, 1922, at the Poet Office at New York, N. Y., under the Act of March }, 1879] A Weekly Journal, Published Erery We<kysday and Dated Saturday, by Henoeasy Radio Publication* Corporation from Publication Office, 1493 Broadway, New York, N. Y. Telephone: Bryant 4796. Vol. II, No. 25. Whole No. 51 March 17, 1923 15c per copy, $6.00 a year The First Church Radio Broadcasting Station CALVARY Baptist Church, New York City, has installed a complete radio broadcasting system for sending out Dr. Straton's sermons and the special music in the regular services of the church. This is a regular licensed station and the call letters ire WQAO. Calvary is the first New York church to nstall its own independent broadcasting station. Dr. Straton, in speaking of this advance step in the :hurch, said: "I am delighted with it. We have given the system a thorough test and it has proved very suc- cessful. I am a hearty believer in the use of radio for broadcasting the truths of religion. I believe that radio "We had, too, another evening a most interesting and remarkable incident when we were testing out to see whether the system would successfully broadcast the music from our great new organ. In the prelimi- nary announcement our operator had requested any outstations who picked up and heard the music to notify us, if possible, by telephone whether or not it was going successfully. "While our Choirmaster was playing the organ here in the auditorium in this test, the telephone bell rang and my secretary answered. He was told that the music was coming perfectly to a receiving station far (C. Kadel and Herbert) Radio room of WQAO, the first church broadcasting station established. CeoTf* F. Koatcr, MX ton of Calvary Church, Now York City, who loatallrd and built the eat. is destined to take a place second only to the news- papers as a means for immediately and directly reach- ing the masses of the people. "The people will not get any doubts or negations or question marks from the Calvary pulpit. I shall try to continue to do my part, as the Bible expresses it, in 'tearing down the strongholds of Satan' and I hope that our radio system will prove so efficient that when 1 twist the devil's tail in New York, his squawk will be heard across the continent! "I gave a brief talk the other day from the Calvary pulpit simply to test the apparatus, and I was delighted with the responses that came in from far and near. (C. Kj.lel jnd Herbert) Rev. Jobs Roach Straton, pastor of tha Calvary Baptist Church, New York City, preaching a esrason into • special transmitter. This was the first church to operate its on brnaaVastnia- station. away, and when Mr. Wilson expressed his pleasure, the friend at the other end of the line said: 'It is just as clear as if I were sitting in the auditorium.' "1 hen he said: 'Here, you can hear it over the phone; I will hold my amplifier horn to the telephone and you can hear it.' He did this and Mr. Wilson heard the music that was going out by radio from the Calvary audi- torium to the far away radio receiving station, and then coming back to him over the telephone with perfect distinctness." Dr. Straton has stated that, in his ojn'iv. casting of sermons and services from t1 would not ten'i to ke^p peop'c awnv '.'< • Digitized by Google

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4 RADIO WORLD How to Make a Cabinet for Your Radio Set By Kenneth Malcolm MANY radio bugs devote their entire energies to the working of their sets and completely overlook the appearance. Some even believe that a shabby set will produce better results than one more carefully dressed up. However, it will be found that a correctly designed set will actually work better if the parts are neatly arranged and carefully wired. Further, if your set is properly housed in a good cabinet, it will find greater respect in the eyes of the outsiders who do not know and appreciate your set as well as you do; therefore, its apparent value will be increased. Then, again, there are many other radio bugs who would like to have a good cabinet, but don't know just how to make one. It is for them that this article was prepared. Bfivri Fc&e Diagrams illustrating the various steps in making a radio set cabinet. The purpose is to help the person with limited means and few tools make an nnpretentious but adequate cabinet to house his pet radio set. All the tools necessary comprise a saw. hammer, screw- driver, try-square, pencil, foot-rule and several sheets of sandpaper of different grades. A plane, nail-set and small hand-drill would also be useful. For certain classes of finish a brush is necessary. If you haven't all the tools mentioned, the first thing to do is to buy the best or borrow what you can. You can do better work with a few good tools than with many poor ones. If you can afford only one saw, get the cross-cut variety. Se'ect a hammer and screw-driver to suit yourself. A smoothing plane with an 8 or 10-inch face will be best. The wood, or stock, may be found about the house, or can be bought of a cabinetmaker or lumber dealer. The stock for the average size cabinet should be about three- eighths of an inch thick. Heavier wood is clumsy and thinner wood is not strong enough for any but very small cabinets. The base may be thicker — say one-half to three- quarters of an inch. If you can get the wood "dressed," meaning planed smooth, at the place where you buy it, do so. In most cases you can have it cut to width on the machine ; if you can, so much the better. Choose wood to suit your taste and pocket-book. The better cabinets are usually of oak, mahogany, or walnut Cheaper cabinets, easily made and finished up nicely, are made of bass or whitewood. This wood is good for be- ginners to practice with, at least until a certain amount of proficiency is achieved. It can be stained in any shade. It is advisable to make out a list of necessary stock be- fore you go to buy your wood. This will save the possi- bility of having too much or too little. Be careful to allow for the waste in cutting and truing to exact measurements. Always remember whether you are following inside or out- side dimensions. The same general rules maintain for a cabinet of any size. Allow for the cover when determining the width of the back piece. Also allow for the cover when cutting the ends. Allow for the thickness of your panel when determining the projection of the front of your base. If you cannot get the side edges dressed be sure and allow extra width for smoothing and truing them up. It is cus- tomary for the grain of the wood to run in the direction of the longest dimension of a piece. For those who must take wood as it comes there is a definite procedure for truing up. The drawings illustrate this clearly. Select an edge running with the grain and straighten it up with your plane. Move your plane in the direction the grain runs, and not against it. Try both ways it yon are uncertain and you will soon recognize the right one. The mistake is made by many beginners of setting the cutter of the plane too heavy. Use the minimum pro- jection of the cutter sufficient for smoothing, otherwise you only waste time and wood. This is edge No. 1. Ffom this edge, with a pencil, mark the opposite parallel edge, at the correct distance. Now select the end that appears the most square and snip its farther corner off, within the waste space, with your plane. The plane should move in the direction of the little arrow. When you work on end grain you should set your plane cutter very fine, and instead of heading the plane straight along with the wood you should push it forward at an angle. Work toward the chopped off corner and never against it. When that end is true, and squared with the first side, mark it No. 2. Next go to the other end and snip its corner off as you did with its neighbor. Carefully mark the length from the first end and plane down to the line, this time also moving in the direction of the cut end. Test occasionally with your try-square. Never try to make the plane do the work of a saw. If there is much wood to be taken down it is best to first saw near the line, and then true up with a plane. This is edge No. 3. The truing of the remaining edge finishes the job. All pieces should be squared up the same way. If you have no plane, be careful and saw close to the line you have made. Some very good boxes may be cut out with the use of the saw alone. The base takes on a more finished appearance if three of its edges are bevelled. This is done with a plane. As {Continued on next page) Digitized by Google

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RADIO WORLD 5 Valuable Loop Antenna Hook-Up for Single Tube By Arthur G. Shirt AMATEURS who are not experimenting with the Flewelling super-circuit or with other cir- cuits employing super-regeneration, find it very difficult to operate a single tube set on an indoor loop A loop is a comparatively poor absorber of radio energy, but on the other hand, its directive powers make possible the bringing in of one station to the ex- clusion of all others. For this reason, it is preferred by some amateurs, while others use the loop because it is the only device they conveniently can use. Whichever the case, the hook-up accompanying this article will prove of value. It is for use with a single tube regenerative set. It will be noted that the loop is grounded, which really makes it function more like an outdoor antenna than as an indoor loop. Some of the directive qualities are lost, of course, by having the loop connected to the ground in this way, but this is more than made up for in the increased efficiency of the circuit. This circuit tunes very sharply and demands fine ad- justment. For this reason a vernier condenser and vernier rheostat are recommended in their respective places as shown. For amateurs who cannot afford three, four or five tube sets, and who cannot, for various reasons, employed an outside antenna, this hook-up, permitting a loop to be used successfully with a single tube, will prove of inestimable value. Other amateurs should find a place for it in their notebooks. (Continued from preceding page) the box must be as strong as possible, the top is sawed down its length about an inch and a half from one edge and the small piece is made stationary — that is, providing you want a hinged cover — otherwise the whole top is fast- ened down. Now comes the assembling of the parts. • Either nails or screws may be used for the joining. If properly driven, nails are entirely satisfactory. Gluing, in addition to nailing or screwing, will make a stronger job. Finishing nails an inch long are about right for cabinets using the size stock mentioned. If you use glue you might find the liquid prepared glue more convenient, although not quite as strong as the hot glue. Two little brass hinges will be needed, and also a little flat hook, if a hinged cover is wanted. Coat the two edges (the edges that fit against the side pieces) with glue (if glue is to be used). Put it on thin, for it is the glue-coated surface and not the glue itself that is strong. Now nail or screw on the two end pieces. Don't drive the nails straight in, but at an angle, as shown in the drawing. Now put on the narrow top piece. Next you can fasten on the bottom. Flat-headed screws would be prefer- able to nails in this case. If you have a hand-drill you can first drill the holes for the screws in the bottom piece and then countersink them by twirling the tip of a knife blade in the hole. If the screws go in hard, a little soap or oil on them will ease them up. The hinges can be fitted next. To do this you will have to place them in the position you want them to go and then carefully trace their outline on the wood. Between the lines where the hinges are to go the wood must be cut away to the depth of the thickness of the hinge plate. This may be done with a chisel or a sharp knife. It must be done on both the under side of the cover and on the top edge of the back. After this is done the hinges may be placed and fastened in position. The hook on the side can better be fitted after the finishing of the cabinet has been completed. The next process is the sandpapering. In order to be able to get an even pressure, and to prevent rounding the edges, the sandpaper should be mounted over a block as shown. Use a medium coarse paper first, and then a fine one. Re sure and remove all the scratches and other sur- face marks, for upon this preliminary work depends to a large extent the final finish. With the aid of a nail or a nail-set drive the heads of the finishing nails a little below the surface. Fill the holes above the heads with putty, wood plugs, or wood filler. The most popular finish for radio cabinets seems to be mission or early English oak and mahogany. A wood dye or stain is the first thing to be applied. You can get this from any paint shop in the shade you want It can be either applied with a brush or a piece of cotton waste and dries thoroughly in a few hours. If you are using mahogany, oak, or any other rather open grain wood, or wood where the pores plainly show, you must use a filler for best results. This comes prepared in paste form in different tints. Use the tint that most nearly matches the stain. It can be applied with some blunt-edged tool, such as a putty knife Be sure and fill all the little holes, but rub all off the surface of the wood, so that it is finally perfectly smooth. Close grained woods such as pine, brich and white wood do not need a filler. Next comes the final finish. This usually consists of several thin coats of shellac One coat should be applied with a brush and allowed to dry thoroughly — and be sure it is thoroughly dry. Now go over this surface with a piece of very fine sandpaper or a piece of steel wool, to take off any rough spots, and to make an anchorage for the next coat Brush off any dust and apply the next coat. You must work fast with shellac, for it dries quickly. Two coats are generally sufficient to give a pleasant luster to your work. If you want a dull or satin finish you can go over the second coat with the fine sandpaper or with steel wool, and afterward give the cabinet a rubbing with furniture oil or with prepared wax. Use very fine sandpaper for this purpose — No. 00. preferably — otherwise you will ruin the work you have already done. For those who prefer less trouble in finishing, what is known as a varnish-stain can be applied directly after the sanding. This stain contains both color and gloss, and while it does not make as nice a finish as the longer method, it is quite satisfactory for those whose require- ments do not include a "piano" finish. With the addition of the hook and screw-eye your cabinet i- finished, and but awaits its panel and set. Digitized by Google

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6 RADIO WORLD Make Your Taps Neater Broadcasters Increase Eleven in February By Arthur S. Gordon AFTER you have wound the primary of that home-made variocoupler so tightly and have taken out taps that are the proud equal of any found on commercial instruments, it is somewhat dis- couraging to have them pull away from the cardboard tube, as most tapped turns have a habit of doing. The fault is not in the cardboard tube nor in. the wire used, but in the method of taking out the taps. The usual procedure is to bend back a loop in the wire and twist it close down to the tube, leaving a small eyelet to which the connecting wire can be soldered. While this arrangement will stay taut for a while, it is bound to loosen and, in many cases, the whole coil has had to be re-wound. OF TAKING) OUT Diagram Showing Arthur S. Gordon's Method of Making Neat Taps. In the interests of neatness and thoroughness, there- fore, the following method of making taps is sug- gested : After you twist the loop as before, instead of going on with the winding, bend the tap down and wind the next two turns over it. Then bend the tap up again and continue until the next tap. Now, with every tap held down by the two succeed- ing turns, there is no danger of stretching or loosening. Even if collodion or coil cement is not applied, the turns will hold together, and not only will you have a tuning coil that is exceptionally neat but you will also have one that will remain exceptionally neat until its last and probably distant day of service. AN increase of eleven broadcasting stations is shown on the records of the Department of Com- merce during the month of February. On Feb- ruary 1 there were 570 stations licensed to broadcast entertainment data and news while on March 3 there were 581 broadcasters operating. During the past month 24 new licenses were issued to broadcast, but 13 old stations ceased to function. Of the total stations transmitting entertainment today, 28 are Class B stations operating on 400 meters, the balance being on 360. Four new stations licensed during the week ending March 3, follow : Call Station WSAC Clemson Agricultural College, Clemson College, S. C. 500 watts KFDV Gilbrech & Stinson, Fayetteville, Ark. 100 watts WWAY Marigold Gardens, Chicago, 111. 500 watts WRAB Savannah Board of Public Educa- tion, Savannah, Ga. 100 watts The thirteen stations which were dropped during February follow: Call Station KFED Billings Polytechnic Institute, Billings, Mont. WKAG Bruce, M. D., Edwin T., Louisville, Ky. WIAX Capital Radio Co., Lincoln, Neb. WNAF Enid Radio Distributing Co., Enid, Okla. WOH Hatfield Electric Co., Indianapolis, Ind. WLAF Johnson Radio Co., Lincoln, Neb. WDAR Lit Brothers, Phila., Pa. WLAR Mickel Music Co., Marshalltown, Iowa. WDY Radio Corp. of America, Roselle Park, N. J. WHAF Radio Electric Co., Pittsburgh, Pa. WJK Service Radio Equipment Co., Toledo, Ohio. WJAE Texas Radio Syndicate, San Antonio, Tex. WDV Yeiser, Jr., John O., Omaha, Neb. Radiograms THE suggestion has been made that a course in the practical building of radio sets be established in the manual training departments of the public schools of the country. No better training for a boy could be imagined than this. • * * IN its issue for October 7, 1923, Radio World published a list, complete to that date, of the broadcasting stations of the United States and Canada. In earlier issues had appeared other complete lists. In response to numerous inquiries, Radio World is preparing another list of broadcasters which will be corrected up to the date of publication in an early issue. » * * A SNAPSHOT, taken by a wireless operator on a small Pacific coastwise steamer, is the latest clue in the possession of the authorities in the nation-wide hunt for Clara Phillips, former chorus girl, the escaped hammer murderess. The picture was taken secretly when the wireless operator, disguised as a waiter, carried a meal into the cabin occupied by the supposed "tiger woman." * * * DURING the year 1919 only 50,000 words were transmitted by Italian radio stations. Based on the year 1922 it is esti- mated that in 1923 Italian radio stations will transmit 7,000,000 words. Station I DO, Rome, operating on the 11,000-meter wave length, sends press messages direct to the New York Times radio- receiving station daily at 12 o'clock and 5 p. m. A new station at Coltano soon will be in operation with sufficient power to send traffic direct to New York. LOHENGRIN" was the second complete opera to be broad- cast from WJZ, following the success of "Die Meistersinger," which was given at the Manhattan Opera House to the radio audi- ence via the Radio Corporation-Westinghouse station in Newark, New Jersey. * » * A WIRELESS press dispatch from Berlin, Germany, to the New York Times states that during the last few days experi- ments with a new system of wireless telephoning were made from a new sending station near Berlin. Letters received from Holland and Switzerland brought news that the German electric waves did not progress on their mission without fierce opposition from die Eiffel Tower in Paris. * » * THE American Telephone and Telegraph Company proposes to increase its capital stock from the present authorized total of $750,000,000 to $1,000,000,000. If approved by stockholders, who will meet on March 27, this will make the company the largest corpora- tion in the United States. No new stock offering is contemplated in 1923. The additional stock is needed to meet commitments under the offer made stockholders on August 24 last; for conversion of convertible bonds and for subscriptions already made under the employes' stock plan. During the year 1922 over 600,000 stations were added to the Bell System, a larger increase than in any pre- ceding year, bringing the total to more than 14,000,000. Studies and experiments in wireless telephony have also been continued. The annual report refers to the series of trans-oceanic experiments which were undertaken by the company late in the year, which culminated in continuous messages being sent for a period of about two hours on January 14, 1922, which were distinctly heard in London. Digitized by Google

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RADIO WORLD 7 The Royal Flying Corps Designs a Compact Set (C. Pkotoncwi, N. Y.) The portable Mt designed by the Royal Flying Corps and used by tbam in gnat number*. This sot la enclosed la • leather case, smaller than the rerulatkm suitcase, and la absolutely complete fa itself. When not in ass the ocver folds up and the set can than be carried wherever it la necessary, with no more trouble taking your dress suit to the train. THE Royal Flying Corps, of England, recently brought out a portable transmitter and receiver which for utility and usefulness, goes a long way toward being a perfect instrument. It is all con- tained in a small suitcase and when not in use can be carried very easily from place to place. In the matter of size, it is much smaller than the regular dress suit case, as can be seen by comparing the size of the meters and switches in the illustration herewith with the width of the case itself. The compartment on the extreme left houses the necessary batteries for the operation of the set, in case the current that generally is furnishel by the small generators on the airplane should go out of commis- sion. They are of course small and not capable of de- livering much power, and therefore cannot be ex- pected to operate the set over long distances. The meters shown in the center are for the determi- nation of the different current values such as the radia- tion current, etc., when the set is used in the air. This, of course, furnishes the operator with an accurate check on all his instruments and he can tell how his signals are going out. The receiver is of the type in which the coupling is fixed, and the variation of the inductances is accom- plished by means of the switches shown. London Restaurant Provides Radio for Patrons WHAT is probably one of the most novel de- velopments in the way of radio entertain- ment was recently brought out by an enter- prising London restaurateur. He had noticed that a great many of his patrons were radio fans and that instead of sitting quietly at the table after a bit of food they would all put on their hats and "go up to Romey's 'ouse, to listen to the radio." Now that couldn't be allowed. It was simply unbearable to the proprietor to see his trade jog away in such fashion. So he thought and thought and finally questioned himself something like the following: "Why not put up one of the bally things, and then instead of going to Romey's 'ouse, why they'll sit 'ere and henjoy a quiet (C Keystone View Co.) Four ardent English radio fans who have adopted up-to-date restaurant in London as their recreation : because of the fact that the owner and proprietor of the restaurant has very thoughtfully equipped all the tables with receiving sets. A good way to draw trade and a tip American restaurateurs. cup o' tea." No sooner said than done, and now the happy patrons can sit in "Jackie's" and have their bit to eat and then listen in at the same time they are hav- ing a quiet little game of rummy. This innovation has not only helped the restaurant keeper to retain his old trade, but it has attracted a lot of new customers to his place because "it's the only place in deah ol' Lunnon where you can listen in while you're having your joint and ale." The above statement is not a mere supposition, but is an actual fact as can be seen by the illustration here- with, where is seen a group of radio fans enjoying a radio concert, while in the midst of an exciting game of "nap," a game that is somewhat similar to our rummy. Digitized by Google

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8 RADIO WORLD How to Build a One Tube Dry Cell Set By P. F. Albright SINCE the publication of the report of my DX record with my WD- 11 one tube dry cell set in Radio World of February 10, 1923, I have been fairly buried in inquiries from every state in the Union for a detailed description of my set." It is impossible for me to answer each inquiry directly. I am, there- fore, asking Radio World to publish the following brief description of my set. I do not claim that I have anything revolutionary in radio, but I do know that my set works, and works wonderfully well, for as I am writing, at Englewood, Col., I am hearing with surprising volume and clearness a program being broadcasted over Radio WSY, Bir- mingham, Alabama, by the Booker T. Washington Glee Club, of the Tuskegee Institute. I see no reason why any one cannot duplicate my experience, if he follows the description and uses care and patience in the con- struction of his set. The only change I made in the Miller circuit as published in Radio World was the substitution of a specially wound inductance for the regulation fifty- turn honeycomb coil. This inductance was made as follows : At one end of a cardboard tube three inches in diameter and three inches long I wound fifty turns of No. 22 DCC wire honeycomb style. On the remain- der of the tube was wound eight single turns of the same wire — plain winding — in two groups of four turns each and connected to the inner end of the honeycomb winding. The two groups of four turns each function as the stator of a miniature variometer and are spaced about three-eighths of an inch apart so as to allow for a shaft carrying a rotor in the form of another card- board tube one inch in length and of as large diameter as will turn in the larger tube and clear. This is also wound with eight turns of the same wire and spaced as on the stator, and is mounted on the shaft so that the rotor windings come directly under the stator wind- ings. The coils of the rotor, stator and honeycomb coil are connected in series and placed in the circuit so that the aerial lead goes first through the rotor, then the stator, then through the honeycomb coil. This little variometer acts as a vernier on the inductance and accounts for the fine selectivity of the set. As many as six different stations have been tuned in within the range of a 100 degree dial without changing the condenser setting, and I am able to separate two stations with a movement of but four or five degrees on the dial. I am giving herewith a diagram of the circuit and the values of the parts. I want to assure you that too much attention cannot be given to the grid leak as it is extremely critical. I used a Remler of the pencil mark type and a very hard pencil and then found that its adjustment required considerable patience. The rheostat must be of the vernier type for long distance work and the more sensitive it is the better. Mine is home-made. My set is wired with No. 14 tinned copper wire and every possible joint soldered. The parts are mounted on a 6x12 inch bakelite panel and carefully shielded with tinfoil and grounded. Mount the induc- tance as far from the variable condenser as possible to avoid capacity effects while tuning. My aerial is stranded copper 100 feet long and 25 feet high with lead-in at one end. A good ground is essential. Mine is a water pipe with connection made as near the en- trance from the street as possible. These things may seem of minor importance, but I have found that one cannot be too fussy about such things as good ground, soldered joints, etc., if he expects his set to reach out and bring in the distant stations. I shall be interested to hear from brother DX Night Owls who build their sets from this description telling me about their results. Amateurs Increase THERE is still great interest in amateur radio telegraphy. This fact is shown by the increase in general and restricted amateur licenses issued by the Department of Commerce since January 1, which number 601. On January 1, there were 17,102 amateur licenses in effect, and on March 1, there were 17,703. These figures do not include 617 other non-commer- cial stations, which comprise 134 technical and training school stations, 297 experimental and 186 special ama- teur stations. , The distribution of special amateur licenses by dis- tricts is as follows, showing the Chicago District, in- cluding northern peninsula of Michigan, Wisconsin, Illinois, Kentucky, Indiana, Minnesota, Iowa, Missouri, 601 Since January 1 North and South Dakota, Nebraska, Kansas and Colo- rado, points : District Headquarters Total March 1 1. Boston 2,490 2. New York 2,589 3. Baltimore 1,919 4. Norfolk 420 5. New Orleans 825 6. San Francisco 2.019 7. Seattle 863 8. Detroit 2,749 9. Chicago 3,729 Total Special amateurs 17.703 Digitized by GOCK

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RADIO WORLD 9 A One Tube Super-Regenerative Loop Receiver By JV. S. Thompson THE trend in modern receiving sets seems to be toward simplicity in tuning and construction. This gives rise to the problem of simplifying the best circuits without losing their advantages. . Probably the most power- ful amplifier of signals that is known today is the set that Major Armstrong calls his "flivver." This set can be built using one, two or three tubes, depending upon whether each tube has one or more duties to perform. In the one- tube set one might say that the tube is made to work over- time, but as long as one tube can accomplish the work satisfactorily it would be extravagant to use more. Our problem, then, is to design a one-tube, super- regenerative set, making the tuning and the construction as simple as possible without losing the tremendous amplify- ing power that is a characteristic of this circuit A loop to pick up signals is used because there seems to be no advantage in using an outdoor antenna. If we use an antenna and couple it to this set the coupling will have to be so loose to eliminate noise that we gain no signal strength. The simplest way to tune the grid circuit of a set using a loop is to make the loop of the correct number of OLIS'OO oo% c Fig. L Diagram of tba lopr-i agaaa mhn a*t a* diicrftia' in «ha act panytnc taxt. The jack Jl fa) for tha buartion af oithar loop or ana turns and tune with a condenser in parallel with it. But to effect regeneration we must have a coupling between the grid and the plate circuits, so we will use the internal capacity of the tube for this purpose. This means we must have a tuned plate circuit, which is accomplished by placing a variometer in this circuit. The advantages of this type of regeneration are many, and, inasmuch as it suited our purpose, it was used. The next detail was how to make the tube oscillate at the high frequency necessary in this circuit. The usual method is to place in the grid and plate circuits honeycomb coils of high inductance, shunt them with variable condensers and couple them inductively. This method means that the operator must adjust the two con- densers and the variable coupling in order to tune. By matching the honeycomb coils, omitting the variable con- densers and coupling the coils with the fixed condenser, this part of the set needs no attention at all after once built. A rheostat for varying the filament current is necessary ; so in the completed set there are only two tuning controls and the rheostat. A word as to the advantages and limitations of this set. Primarily, it is more of a power amplifier for signals from nearby stations than a long-distance receiver. For use on 360 to 400 meter work it will give amplification enough so that, using a good loud speaker, it will fill a small room when the station is within a radius of 75 miles. Therefore, this distance is practically the limit for broadcast entertain- ment. However, due to the peculiarities of the circuit, long-distance work may be expected on the amateur wave lengths. The above causes the writer to recommend this set for home entertainment when near a broadcasting station or for a good long-distance receiver for short wave length work. The values for the constants that will allow cither use have been given. As to the construction, the writer does not want to bind the builder to any fixed measurements, but to give a few suggestions and pointers that may make the task a little simpler and the product a little better. A good loop can be made by winding ten turns of No. 18 copper wire around a form three feet square, spacing the wires about l/2 inch apart. On the bottom of the vertical standard attach the brass parts of an ordinary torpedo plug. Most plugs easily can be fixed for this purpose by removing the tip posts and screwing the plug to the loop. L ITOO PC i) fcQefc Ifll o Ifc ea. G. -HP" FU. JL Too vtrar. Not* to* fact that tha two In Figures 2 and 3 the dotted lines represent the mounting of jack J for the loop and the coupling condenser C on a sub-panel back of the main panel. This sub-panel, as shown, is fastened to the top of the variometer and to a t leat on the end of the cabinet, or to a panel brace if the set is not to be enclosed in a cabinet. The sub-panel should (Continued en nest poge) Digitized by Google

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10 RADIO WORLD Radio Control Up to Secretary Hoover THE White radio bill died in committee along with a number of other important legislative docu- ments when the 67th Congress adjourned on March 4th. The House and Senate do not convene until December 4th, when a new bill probably will be intro- duced— but that is nine months away. Whether Secretary Hoover can manage to keep the ether from getting more jammed with broadcasts and other radio communications without legislation, re- mains to be seen. Lack of a new law makes it neces- sary for the Department of Commerce to continue under legislation enacted ten years ago when broad- casting was unknown and there were few commercial and amateur stations. It is probable that the Secretary will undertake the partial re-allocation of wave lengths, within the limits of the existing radio law, in an effort to reduce inter- ference and make for peace in the ether. Just what plans the Department of Commerce has for improving conditions in the present radio pan- demonium are not known but a plan for execution within a few months is being worked out, it is under- stood. The decision of the District Court of Appeals requir- ing the Secretary of Commerce to re-issue a license to the Inter-City Radio Company of New York, although that station had been severely complained of due to in- terference will be appealed. Secretary Hoover and his solicitor have taken the matter up with the Attorney General's office request- ing that the case be appealed to the Supreme Court of the United States. It was the action of the Court of Appeals that caused Secretary Hoover to state recently that : "This removes the last shred of the department's authority over radio." RADIO WORLD'S ANNIVERSARY NUMBER RADIO WORLD is now at work on its Special An- niversary Number, dated March 31, published March 28. This issue will celebrate the beginning of the third volume of RADIO WORLD, the great national illus- trated weekly. Last page of red form goes to press March 19. Last page of last black form closes March 23. Our regular advertising rates will be in force as fol- lows: One page: One time— $150.00. Half, Quarter, Third and Two- thirds pages at proportionate rates. On inch, one time— $5.00. Per agate line, $0.40. On four consecutive issues, 10 per cent discount. On thirteen consecutive issues, 15 per cent discount Cover and preferred position rates made known on application. No extra charge for advertisements in two colors, if copy reaches this office on or before March 19. If you want your advertisement printed in two colors in this unusually important special number, say so and have copy reach publication office on or before March 19. RADIO WORLD has been increasing in circulation and influence every week, and this has been especially noticeable since the advent of 1923. The radio public has learned that the columns of this publication reflect the news and developments in radio weeks ahead of the monthly publications. Write or send copy and order now and get the best possible publication value by being represented in the Special Anniversary Number of RADIO WORLD. RADIO WORLD, 1493 Broadway, New York City. (Continued from preceding page) Mounting the apparatus back of the panel, as shown in Fig. 3, allows the grid coil to be very loosely coupled to the variometer, thus aiding to stabilize the regeneration. Standard fixed honeycomb coil mountings can be used for this purpose, although any mounting that the builder may wish to use will be satisfactory. By using a vernier con- denser for tuning the loop and a vernier rheostat the results obtained will be well worth the added expense. In purchasing the phone condenser and the coupling con- denser be sure and get mica condensers and a type which have the plates and mica held firmly together so there will be no chance for the capacity to change. Always remember that added expense in buying the best apparatus pays good interest by giving better results. The popularity of the A battery is very important, for the grid should have a normal negative potential for best results. The value for the B battery depends upon the tube used, remembering that high voltage usually means greater amplification. Very satis- factory results have been obtained using the tube shown, with 90 volts for B battery, although the best results were obtained using the Signal Corps' tube, VT2, with a higher plate voltage. The two honeycomb coils should be placed perpendicular to each other, using the value for the coupling condenser shown. This value can be changed to suit the builder if he desires to change the pitch of the high fre- quency note. All connections should be soldered ; no wires should be close together or run parallel, and the panel should be shielded, grounding the shield to the A battery. The following apparatus will be necessary : 1 Vernier air condenser, 0.0005 mfd $4.00 1 Variometer 5.00 1 Hars amplifier tube 6.50 1 Vernier rheostat 1.85 2 Single-circuit jacks 1.00 1 Mica condenser, 0.005 mfd 40 1 Mica condenser, 0.002 mfd 40 1 Vacuum tube socket 1.00 1 Panel 2.50 1 Sub-panel 50 Wire, binding posts, etc 1.00 Total $24.15 In tuning for the first time turn up the filament rheostat until a very high-pitched note is heard. The filament will usually be a little brighter than customary with the ordinary set. Now set the tuning condenser at about one-quarter mesh and then turn the variometer slowly. The first sign that the set is working properly is a roar that is always heard when a station is very nearly tuned in. When the correct setting is found this roar will stop and there will be no noise when the signals are being heard except those caused by static or other QRM. This set, due to its tre- mendous amplifying power, will amplify noises of the air so that there will always be some noise present, as with any other set; but this noise will not be found troublesome to any great extent. Digitized by Google

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RADIO WORLD 11 Another WD-11 Hook-Up to Try Out By C. White, Consulting Engineer T'HE diagram herewith shows nothing more than a variation of the common type of direct feedback. This style of regenerative circuit has come into amateur popularity largely owing to the fact that with its use it becomes possible to secure a smoother adjustment for the critical regenerative point. With the ordinary feedback system the tickler coil is usually placed in series with the "B" batteries and the phones. As the coupling between the tickler and the main tuning inductance would be increased the adjustment would suddenly begin to get extremely sensitive. With some outfits this adjustment at the correct point would be so sensitive that it would be next to im- possible to hold a distant station without the most critical tuning. To receive distant stations with one tube or one tube and two stages of audio-frequency, the detector tube must be 2« u -t Diagram showing the new WD-11 hook-up de- scribed by Mr. White in the accompanying text. The condenser CI is a small capacity variable (11 or U plates). The condenser CZ Is' of .teas capacity (23 plates). The tuning inductance is either a honeycomb coil, variometer, or single slide tuning coil, which gives quite a large amount of flexibility to the constructor. —A fi/fongt held on the verge of oscillation, but must not at any time go into oscillation. This particular point is called the maximum regenerative point, and by holding tube at the desired point the greatest volume of the rectified signal is obtained. If, however, the tube slips or rather jumps into oscillation then it is necessary to turn the tickler controls back and try again to approach the right point. The circuit outlined in this article has the advantage of being able to approach the regenerative point with ease and smooth adjustment without getting sensitive and causing the tube to jump into violent oscillation. Like most good circuits it has a drawback, which is the fact that the value of grid leak resistance and grid leak condenser capacity is very critical, but after it is once ascer- tained by experiment for the particular bulb that is being used, no further trouble is encountered. Aside from the determination of the grid leak units, the receiver is very flexible as to its other parts. Many slight changes can be made in the types of tuning inductances and arrangement of the condensers without destroying the efficiency of the circuit. The ambitious amateur will try out several changes and additions before placing the set in a cabinet. Hook the parts up, change them around, try out several different values of grid leak units, change the polarity of the A battery, and purchase an A battery potentiometer if any other type of tube besides the WD-11 is employed. The condenser C-l is an air variable containing 11 or 13 plates. C-2 should be of the same type but should have at least 23 plates. The grid leak condenser should be a small mica condenser. With a circuit that is critical as to the value of grid leak units, it is never good practice to purchase any grid leak condenser other than a mica in- sulated one, because the capacities of other types, such as the paper ones, are apt to be too variable and not hold their calibrated capacity under all conditions. Likewise, the grid leak should be of a good make. The types of grid leak resistances that are mounted in small tubes are very reliable. Of course, it would not be a bad idea to purchase a good variable mica grid condenser and a variable grid leak re- sistance. The condenser C-3 is nothing more than the cus- tomary phone bypass condenser having a capacity about .001 mfd. Sometimes when one pair of phones only is used, better results are obtainable when C-3 is removed completely from the circuit. With more than one pair of phones in the plate circuit the omission of C-3 will be attended by rather serious and noticeable distortion, espe- cially when voice or music is being received. The tuning inductance L is very flexible. It can be either a simple single slider tuning coil, a spider web coil, a variometer, or a honeycomb coil, although a coil of variable inductance is here preferable. If you are changing over from an old crystal hook-up which used an ordinary tuning coil with one or more sliders, try the circuit out with it first For panel mounting,' however, another style of in- ductance must be employed, since the single slider tuner does not lend itself well to panel style of control as does the variometer. The spider-web and the honeycomb are theoretically izf. the same class, since their inductance can not be varied evenly. Good results have been obtained with both owing to the fact that, because they are practically free from distributed capacity, sharper tuning and selectivity is readily possible. But, on the other hand, their use makes it neces- sary to be still more critical in the preliminary {^termina- tion of the grid leak capacity and leak resistance. lA spider web coil with taps can be constructed in ordfcr to obtain variable inductance. This coil should be wound with No. 24 D. C. C. magnet wire on a form with a two-inch inner diameter and a five to six-inch outer diameter. Taps should be made about every ten turns. It is far better to purchase a good grade of spider web form already cut out of reliable insulating fiber instead of cutting one yourself from weak cardboard. A spider web coil with taps in this style of circuit will certainly work wonders in bringing in the distant fellows with only one dry cell tube, . By winding your own spider web instead of purchasing a variometer you can save enough to purchase a panel, al- though with a spider web you will have to buy switch points and a switch arm. Some amateurs have found, how- ever, with this type of receiver a spider web coil is superior to a variometer, although costing less to install. United States Radio Exports in 1922 Radio exports shipped out of the country in Decem- ber totaled $163,236 in value, less than the total for November, which was $223,180. The decrease is ex- plained by officials of the Department of Commerce as due to large shipments of apparatus to Argentine in November. In December, Canada took the largest amount valued at $74,344. Total exports of radio apparatus for 1922 amounted to $2,897,799, being more than a thirtieth of the total electrical exports for the year, which amounted to over $63,000,000. Digitized by ' Google

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12 RADIO WORLD Capital Radiations By Washington R. Service A RADIO-CONTROLLED drill was a feature of the Annapolis Gymnkhana held recently. The midshipmen in the drill team wore Ku Klux cos- tumes and in their conical helmets were installed small radio receiving sets. From a sending station on the roof of the gymnasium, instructions were issued to the men in the drill. These were the only directions they received, yet they are said to have executed their orders in absolute unison. From another radio set the sound pi a drum was furnished, to which they kept step. The whole gymnasium was quiet and the drill of the white costumed figures was weird due to the lack of audible orders. * * * A pathetic letter from a blind man in Highmore, S. D., was received by the Department of Commerce asking which branch of the Government was distribut- ing radio receiving sets to blind people. The depart- ment radio officials were forced to reply that the de- partment had no sets to distribute and knew of no appropriation from which such donations could be made. It occurred to the government officials, how- ever, that there was an opportunity for some charitable organization to perform a great public service for those who cannot see. Most blind, they point out, have no means of receiving information or instruction except when they are read to. Since radio offers an audible means of instruction and entertainment and 570 broad- casting stations furnish programs free during prac- tically every hour of the day, Government radio experts urge that a fund be started from which inexpensive radio receiving sets could be purchased for those un- fortunates who are forced to spend their days in dark- ness. Radio broadcasters are furnishing the material, and some believe there are individuals or organizations who will bring these broadcasts to the ears of those who need them most of all. * * * France has introduced a new method of communica- tion which combines the postal and radio service with her colonies. A service called "radio letters" has been established which, when printed, may be mailed to the transmitting station, radioed to a receiving station and there mailed to their destinations. The charge is said to include postage at both ends of the route and two- thirds of the regular radio charges. The minimum involves a rate applicable to a twenty-word message. Radio letters follow the regular radiograms daily or are moved the second day as day messages. * * * A circular describing how to build a tube set, the third pamphlet on radio construction to be published by the Bureau of Standards, is now available from the Superintendent of Documents, Government Printing Office, Washington, D. C, for 10 cents. Write for'Cir- cular 133, "Description and Operation of an Electron- Tube Detector Unit for Simple Radio Receiving Out- fits." * ♦ * The Mississippi Riven is now the dividing line be- tween the "K" calls of the West and the "W" calls of the East, as far as broadcasting stations are concerned. All new calls issued to broadcasting stations east of the Mississippi will begin with "W" and those west with "K," so the stations can be immediately identified as Atlantic or Pacific when the initial letter is heard. The stations already listed under "K," including KDKA, will retain their original calls. * * * The air traffic commissioner of Denmark recently ruled that all airplanes must be equipped with wireless telephone apparatus. This is held as an important ad- vance in both aviation and communication in Denmark It is a progressive step not yet taken in the United States. Although ships of the sea must be so equipped, aircraft do as they please. After many accidents in aerial traffic over sea routes, with some loss of life, two aerial navigation lines have voluntarily begun to equip their aircraft with radio as a safety precaution. Rear Admiral Moffett, chief of the Naval Bureau of Aeronautics, pointed out the necessity of radio equip- ment or at least pigeons on all aircraft several months ago. All army and naval planes are radio-equipped, at least when on long distance trips, and in addition carry pigeons. The need of legislation for aircraft and aerial navigation already has been pointed out by many American experts. Government Warning to Broadcasters THE Department of Commerce has advised broad- casters, through the medium of the Radio Service* Bulletin, that they must comply with regulations and confine their radio activities to broadcasting. A broad- casting license does not permit special tests of radio tele- phone or telegraph apparatus, communication with specific stations, either ashore or at sea, or any transmission except entertainment, market and weather reports, and news on 360 or 400 meters, as the license may specify. Some stations have stopped acknowledging letters, tele- grams and telephone calls, but they talk to one another, conduct contests, which approximate advertising, and some carry on experiments of various kinds. This practice has become so general that the departmental officials state some new regulations may have to be provided. Special licenses and waves are necessary for code work, station-to-station transmission and experimental work. There are too many stations licensed for such operation now, it is explained, and when the broadcasters enter this field the interference increases. All station owners are advised to give their licenses the '"once over" and familiarize themselves with exactly what they are permitted to do. In the interests of life-saving at sea, based upon "SOS" calls, broadcasting stations are cautioned by the Depart- ment of Commerce to maintain a careful watch while send- ing so that they can cease instantly when a distress call is heard and not interfere with the distress signals and messages relating thereto. This applies particularly on and near the sea coasts. Recently four vessels issued distress calls near Seattle. Washington, on the same day, but so far as was reported by inspectors no broadcasters happened to interfere. The law provides a penalty in the event of interference with "SOS" calls, as is set forth in Section 4, Act of August 13, 1912. Digitized by Google

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RADIO WORLD 13 Methods of Measuring Properties of Electron Tubes Determination of Direct-Current Characteristic^ and Power Output of Generator Tubes THIS determination is the usual step-by-step method of determining the characteristic curves as described in any book on radio measurements (such as Bureau of Standards Circular 74, p. 203). Fig. 3 shows the meas- uring instruments that are necessary and the factors that it may be desirable to vary. The arrangement that has been found convenient to use is shown in Fig. 4 in which Switch for connecting either milliammeter or sensi- tive galvanometer in the grid circuit. Grid ammeter short circuiting switch. Reversing switch for grid ammeter. Reversing switch for grid voltage. Switch and terminals for connecting grid voltmeter. Switch for connecting R, in parallel with Rr Switch for connecting to plate or small tube or terminal at 18. Grid return switch, connecting to + or — side of filament. Filament voltmeter connecting switch. Plate ammeter short circuiting switch and terminals. Plate voltmeter switch and terminals. Plate voltage disconnecting switch. Plate voltage disconnecting switch. Grid voltage terminals. Grid voltmeter. Filament voltage terminals. Standard receiving tube socket Terminals for non-standard or high power tube. Plate voltmeter. Short circuiting switch and terminals for plate im- pedance. Short circuiting switch and terminals for grid im- pedance. ^Terminals for plate voltage. Galvanometer shunt. Grid milliammeter. Filament voltmeter. Filament ammeter. Plate milliammeter. Grid voltage disconnecting switch. Filament voltage disconnecting switch. Mica condenser 0.2 /uf capacity. Mica condensers 0.1 /uf capacity. Grid voltage divided, 3,000 ohms. Filament rheostat, fine adjustment. Filament rheostat, ' rough adjustment. Plate voltage divider, 2,000 ohms. The operations necessary to obtain the characteristic curves of electron tubes consist of making filament, grid, and plate current measurements with the filament, grid and plate voltages set at any desired value varying one of these by steps over a range sufficient to give the desired curve. ' The tube under test is placed in the socket, 17, and switch 7 thrown to the left, if it is a standard receiving or low power transmitting tube, or connected to the terminals, 18, and switch 7 thrown to the right if the tube is non-standard or for high power. The plate circuit is disconnected from the socket 17 and connected to terminal P at 18 for high power tubes in order to prevent a break down of the insulation on the small socket when the high voltage used on large tubes is applied. Switches 20 and 21 are closed. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. Q C, Rt Ra R, R4 The grid voltage, of a value slightly higher than the highest required for the measurement is applied to the terminals, 14, and connected by the switch, 29, which is fused with 0.5 ampere fuse wire, to the voltage divider Rx and by moving the slider on Rx the voltage applied to the tube may be varied continuously from zero to the value ap- plied at 14. This voltage is measured by the voltmeter, 15, when switch 5 is closed, and may be reversed by means of switch 4; the grid being positive with 4 to the right and negative with 4 to the left The grid voltage is ordinarily measured from the negative side of the filament, but by means of switch 8, the grid return may be connected to either side of the filament, to the negative with 8 left and positive with 8 right. The grid current is read on the milliammeter 25, or on the sensitive galvanometer, either one of which is connected in the grid circuit by switch 1. The milliammeter is used to measure grid currents of about 0.02 to 200 milliamperes, but for smaller currents, the more sensitive galvanometer is used. Its sensitivity can be varied by the shunt 24, cali- brations being necessary for each value of the shunt re- sistance. In order to measure current flowing in either direction, the reversing switch 3 is provided, the current flow being positive, i.e., from grid to filament in the tube, when 3 is to the right, and negative with 3 to the left The FI0.3. 3WPUFIC0 DIAGRAM Of CHARACTEAJSne CUftVL ACT-UP grid voltage divider and measuring instruments are shunted by the condenser Clt to bypass radio-frequency current when this circuit is used to make the power output meas- urements described below. The filament voltage is applied to terminals 16, and con- nected by switch 30, through the filament ammeter 27, and rheostat R, and Rs to the filament terminals of 17 and 18, the voltage across the filament terminals being indicated by voltmeter 26 when switch 9 is closed. This switch should always be open when adjusting the filament current as the current taken by the voltmeter flows through the ammeter 27 and may cause appreciable error, particularly with tubes using a small filament current. The plate voltage is connected to terminals 22 and 23. The voltage on 23 should not exceed about 200 volts as it is connected through switch 13 to the voltage divider R4, any higher voltage necessary being connected to terminals 22. Since 22 and 23 are in series, connection should be made to both of these in order to complete the plate circuit. Switches 12 and 13 are fused with 0.5 ampere fuse wire. By changing the slider on R4, the plate voltage is varied over a range afforded by the voltage connected to 23, and (Continued on next page) Digitized by Google

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14 RADIO WORLD {Continued from preceding page) the total voltage applied to the plate, being the sum of thai obtained from the voltage divider- and that connected to 22, is measured by the voltmeter 19. By means of switch 11, the voltmeter can be connected directly t8 the plate (switch 11 to left) so as to measure the actual voltage acting be- tween plate and filament, or (11 to right) to the positive side of the voltage supply to measure the voltage applied to the circuit, excluding the drop across any impedance inserted in the circuit at 20. For ordinary characteristics 11 is thrown to the left and switches 20 and 21 are closed. The plate current is read on the milliammeter 28, which is in series in the plate circuit and can be short-circuited by the switch 10, when not in use. The capacity Cs is shunted across the voltage supply and measuring instru- ments to bypass high-frequency current when this circuit is used for power output measurements. Measurements for the two most important characteristic curves having grid and plate current plotted against grid voltage, with constant filament current and plate voltage are made simultaneously. With the tube in place, and the proper voltages connected, the filament current is adjusted to its proper value, having switch 9 open while reading the current, the plate voltage adjusted and the grid voltage increased toward the negative (switch 4 to the left) until the plate current has been decreased to zero, reading the grid voltage and current. Nbw the grid voltage is de- creased to zero by steps, at each setting the grid voltage and current and plate current being recorded, then switch 4 is thrown to the right and the voltage increased positively, readings being made as before. The plate voltage is read each time to insure that it remains constant. The filament current will vary according to the amount of electron cur- rent flowing in the tube. When a positive grid voltage is applied to the tube, great care should be taken to prevent the high plate current from overheating the tube", by leav- ing the grid voltage on no longer than necessary to obtain readings. This applies more to power tubes than receiving tubes, since high grid voltages are not necessary for re- ceiving tube characteristics. When the grid voltage has been varied over a range sufficient for the characteristic, a few check points are taken to insure that the tube has remained constant during the run. It may be found necessary to adjust the plate voltage each time readings are made as there may be an appreciable voltage drop in the plate voltage divider, R4 caused by the plate current, which changes as the grid voltage is varied. Tubes should be left with the filament burning and the normal plate voltage applied for 2 to 5 minutes before making measurements. Other characteristics may be obtained in a like manner, adjusting the voltages or currents it is desired to hold con- stant first, then varying the remaining ones by steps. (2) Power Output Measurements. The arrangements shown in Fig. 4 may be used to control and measure the various currents and voltages of the electron tube when it is used to furnish power to a tuned circuit. The power output of a tube under any fixed con- dition can be measured by the use of this circuit. For the case of an inductively-coupled circuit Fig. 5 shows the arrangement used, the notation being the same as in Fig. 4. Measurements are made by connecting to the terminals 20, Fig. 4, a suitable radio-frequency oscillatory circuit of known constants. After adjusting the tubes to the desired operating conditions, the radio frequency current is meas- ured, and the power calculated from the circuit resistance and current. Several coils of varying sizes are provided for the grid and plate coupling coils. The plate and grid coils are respectively mounted on the terminal blocks 20 and 21. If an inductively-coupled circuit such as the "Meissner Circuit" is used (see Bureau of Standards Cir- cular 74, p. 210, Principles Underlying Radio Communica- tion, p. 493) the coil for the tuned circuit is so constructed that the grid and plate coils fit into it and the coils are so arranged that the mutual inductance between any . two of them may be varied. The tuned circuit containing a hot-wire ammeter is con- nected to the coils, the tube voltages adjusted to the desired value and the alternating current I recorded. The radio- frequency resistance R, is measured by means of the re- nc*. CHARACTERISTIC CURVE. SET -"UP. sistance-variation method* at the frequency at which the circuit is used. The power output is, in watts : P0 = I'R. From the d. c. plate input voltage Eb, measured by volt- meter 19, and current Ip measured by milliammeter 28, the power input is in watts. P = E I watts 1 B B and the efficiency, disregarding the grid and filament power is P„ = Is R E I B P Unless changes are made in the set-up connections a series plate voltage supply must be used. The capacity C, is connected across thet ijjjgjg AJgwer supply circuits, and # — © 1 LPJlPJcMflmOQj rlG.5. SIMPLIFIED DIAGRAM Of CIRCUIT FOR MEASUREMENT OF POWER OUTPUT OF ELECTRON TUBES. serves as a bypass for radio-frequency currents when the power measurement is made. The coupling coils and out- put coils provided are so constructed as to allow their use in direct coupled, semi-direct coupled or inductively coupled, output circuit. •Bureau of Standards Circular 74, page 180. (While this article U complete in iUelf , it will be followed by other* on the same (abject, and equally important. The first article in this series appeared in these pages last week.) Digitized by Google

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RADIO WORLD 15 Radio and the Woman By Crystal D. Tector THE Japanese cook of a very influential lady in our town recently met our maid when going to market, and Mary reported something as fol- lows: "Sure ma'am, but Kito sez th' madam nearly threw him out the house the other night becuz he strung the clothes up on the wireless that her husband put up, and wants to know if you know any nice lady in the city that needs a cook and don't have a wireless." I certainly have lots of friends, but when a cook draws the line at being employed by a person who possesses a radio set, I think that he is going too far. I don't believe that my friends would think of showing their faces in public unless their ears were red from wearing "the muffs." * * * A FRIEND of ours dropped in the other day and after we had a cup of tea, we naturally started in to talk "radio." She was very much interested, but couldn't understand "what all those little do-funny little dihinkys are twisted for." Then I knew I was in for it, because there is nothing that I dislike more than explaining the theory of tuning to a novice, be- cause they always say, "Oh 1 1 see, then this is that and that is this," or words to that effect, and then I have to go all over it again and explain that this is not that but that that is that, and this is this. Am I right? GIRLS, you ought to have been with F. H. and myself the other evening. We had the grandest ride in a radio equipped automobile. We went touring all over the city listening to the big broadcast- ing stations. Finally, the chauffeur was told to drive down to West Street, the location of WEAF, and when we drew near, the volume of signals was so loud it absolutely was painful to your ears. I can imagine how loud the signals must be received by any one living near that station. • * • THE Orphan Asylum gave a party to the kiddies the other day and, of course, it had to be complete and up-to-date. So some of the foremost radio fans of our "metropolis" (according to F. H.) donated their sets and helped make the party a great success for the kiddies. I donated my (I should say our, because if F. H. sees this he will ask me since when "did you ever own a power amplifier") power amplifier and loud speaker and my next-door neighbor donated her husband's radio-frequency receiving set, and so be- tween the whole lot of us the kiddies had a "radio fest." I never thought that a child could be so happy but those little dears just radiated happiness. If it weren't for the fact that the house couldn't bold them why I'd adopt every single soul of them. WHEN YOU CAN HEAR THESE BROADCASTING STATIONS (Evening Programs Only) Call W-L Atlanta, Ga WSB 400 Atlanta, Ga WGM 400 Arlington, Va. NAA 710 Boston, Mass WNAC 360 Buffalo, N. Y WGR 360 Chicago, HI KYW 400 Chicago, 111 WMAQ 360 Chicago, I1L WDAP 360 Cincinnati, O WLW 360 Dallas, Tex. WFAA 400 Davenport, la WOC 400 Denver, Cola KLZ 360 Dearborn, Mich WW I 360 Detroit, Mich WCX 400 Detroit, Mich WWJ 360 Havana, Cuba PWX 400 Indianapolis, Ind WLK 360 Kansas City, Mo. WDAF 400 Kansas City, Mo WHB 360 Louisville, Ky WHAS 360 Lockport, N. Y WMAK 360 Los Angeles, Calif.f....KHJ 400 London, Eng. 2LO 369 Medford Hillside WGI 360 Minneapolis, Minn WLAGL 400 Newark. N. T WTZ 360 Pittsburgh, Pa KDKA 360 Philadelphia, Pa WFI 400 Philadelphia, Pa WOO 400 Schenectady, N. Y WGY 400 St. Louis', Mo. KSD 400 St. Louis, Mo WCK 3 Springfield. Mass WBZ 422 Toronto, Can CFCA 400 Troy, N. Y WHAZ 3oO * Time not listed. Mon. 10:45- 1:00 10:30-11:30 6:45- 8O0 '7:30^ 10:66 9:00-10:30 7:88- SHIS "8:6bU6'o6 8:38- 8:3* 8:M 7:3* 7:M 7:38- 8:38 8:88-18:88 9:15-10:00 ltiM • 5:00- 7:00 10:00-12:30 7:00-10:15 6:15-10:00 6:30- 7:00 7:30-10:00 7:45-10:00 9:00-12:30 7:45- 9:00 7:30- 9:00 8:00- 9:00 8:00- 9:30 Tuts. 10:45- 1.00 10:30-11:30 7:45- 8:40 7:00- 8:30 7:30-8 00 900-10:30 7iM- t:lS 11:00- 2:00 10:00-12:00 8:38-11:88 Yt» •tiil 7:ii 7:38- 8:98 'si 38-18: 88 8:8808:88 8:30-10:00 9:15-10.00 18:88- 5:00-10:00 7:66- 10 15 6:00- 10 00 6:30- 7 00 9:55- 10-10 7:45-10-00 9 00- 1 1 00 '8 00 7 ,v>. 9 m 8:Oi- 9 .(HI Wed. 10:45- 1:00 10:30-11:30 800- 9:40 9:30-11:00 7:30-10:00 9:00-10:30 7:M- ff:IS 8 00- 10. 00 8:88^18:88 7:9* 10:00-1100 8:88- 7:3* 7:38- 8:38 8:M- t:M siss^ifess ' 8:30- 10:66 islss 5:00- 8 :30 " 7 :00l 10 :15 6:15-10:00 8:00-11 00 9:55-10:10 '9:00-iio6 7:45- 9 (0 7 .lil 9 00 8 (mi O <m 8 IN) 10 (O Thurs. 10:45- 1:00 10:30-11:30 6:45- 8:40 7:00- 8:30 7:30- 8:00 9.00-10:30 7:M- ft IS 11:00- 2:00 10:00-12:00 8:38-11:88 Si St 7:3* 'sis*, iiii 7:38- 8:38 'sisMfeSS 'sist^itist 8:30-10:00 9:15-10:00 Its St 5:00-1100 10:10- 1:00 7:00-10:00 6:00-10 00 6 30- 7 00 7 30-10 .V) 7 :45-10 00 7 .10. 8 OH. 0 (10 9 («l Fri. 10:45- 1:00 10:30-11:30 8 00- 9:40 8 :00- 9.30 7:30-10:00 9:00-10:30 7:88- 8: IS 8:38- 8:38 8:N 7:9* StS* 7:98 7: 38- 8:38 8:88-18:88 '8:36- io -66 18:88 5.00-11 :00 '7000606 6:15-10 00 10 00-12:00 9:55 10 10 7:45-11 :.VI 9 00-11 00 7 .45- 9:00 7 .w. 8 00- 9 00 9 (JO Sat. 10:45- 1:00 10:30-11:30 9 :3(Mi !66 90000:30 7:88- 8:1* 11:15: 3 .00 siisoiVss 8:88-18:38 7:38 SsSS-'iiS* 7:38- 8:38 8:88-11:38 8:88-18:88 8:30-10:00 18:88 5:30- 9:30 8 30 11:00 8:30 10:30 6:00-10 :00 8 30-10 00 9 55-10 :10 906-ii'oo 7 30 8 00- 9 00 9 "0 ** Sunday— 12:00-1 :00 and 9:00-10:00 P. M. t Pacific Time. Note — Type set in bold face is Central Standard Time. Lip' face tvpr i* E.u'ern S'andard Time. Digitized by Google

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RADIO WORLD High Lights of the 1 Second Radio D Pictorially Presented (C. Photonew*; K. HUer. of Rideewood. N. J., and hU lt-watt has been heard 2,000 mile* east of New THE THIRD ANNUAL CONVENTION of the Second Radio District, held at the Hotel .Penn- sylvania, New York City, on March 1, 2 and 3, was the most successful up to date. From the stand- point'of attendance the meeting overtopped those of former years, the attendance passing the 10,000 mark. At the banquet, held on the evening of the last day, the attendance was about 1,000. The speech of Mr. Droste, chairman of the Second District Convention, regarding the attitude of the amateurs and the broad- casters, and how their troubles were amicably settled was a feature of the banquet. Prominent amateurs were then called upon, and told to "Let the folks see what you look like." Some of those called upon were 2BK, 20M, ZUA and his OW, who sometimes "pounds the brass" at his station; 2BRB, 2BUL, 1CNI, 9AWN and several other well known big-timers. A speech by Hiram Percy Maxim, the "big gun" of the American Radio Relay League, followed. The next address on the program was by Inspector Arthur Batchelor, who is a figure well known to all the eastern amateurs and very well known to several in particular. A little comedy was then staged A young man who was supposed to represent CQ was turned loose and started in to run around in circles, much the same as the original CQ hounds do today. He was caught and brought before Judge Public Opinion who sentenced him to bread and water for life. F. B. OM.! The next feature was Margaret Meerle, the Follies

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RADIO WORLD 17 d Annual Convention, ct, New York City Radio World Readers » hotonew*) of ZACC, Mat boo km hoard In of R. Noaoch, IW York Cfer. - - oWtac tko It U of tfco IN watt ryao. (C 2W watt tanllbr of Station XBHY, SrofararJ. Now York City. TUo wu oao of beauty, singing inside the monstrous Adams-Morgan Paragon set, which by the way was one of the features of the show. Mr. George Clark, of the Radio Cor- poration, next gave a humorous talk which caused the assembledge to roar with laughter. Numerous other men spoke and told stories, among whom were Kenneth B. Warner, wearing his two gallon plug hat ; "Paragon" Paul Godley and Win. F. Crosby. This convention proved conclusively that more than ever is the interest in amateur radio increasing. In fact, it is growing to such an extent that it is simply impossible to estimate how things will stand next year at this time. The interest is not alone confined to the younger people, but the older ones are taking up the interest from a transmitting point and delight in telling how fast they can "clean their hooks of all messages." Some of the big features of the show were the trans- mitter of A. H. Grebe & Co. It was a 500-watt trans- mitter of the latest type and was specially licensed for three days, a provisional license being granted and the set inspected before the opening of the convention. Another of the big features was the immense set de- signed after the famous Paragon, and magnified several times. It was so large that it resembled an immense casket, decorated like a set. It sure did look hand- some. Even if it would nearly fill a room, many an amateur would give his boots to own it. On the whole the entire affair was an immense suc- cess, and the banquet was everything that was prom- ised. The folks just had one "good old-fashioned time." Mr*. Dorothy Docker. ta operate the ynmUmUy V«a«aa (C Fotofriml) Da Do F< 3e Lea*, tao eriekaa roaV fM, I I il * ■ ■ it

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18 RADIO WORLD Answers to Readers JflNDLY publish, or refer me to a back number containing a hook-up of a re- generative receiver with one stage of radio- frequency detector and one stage of audio- frequency, one A battery and necessary B batteries. It is not to incorporate a potentiometer?— A. O. Tumbull, 57 Union Street, Sydney, N. S., Canada. If you will refer to Radio World for Feb. 24, 1923, you will find a hook-up such as you need on page 19. T' potentiometer shown in that particular h„. -up, while not absolutely necessary, is advisable because of the fact that it makes the tuning so much easier, especially on the distance stations. You can eliminate it, if you wish. The one lead from the secondary will then connect on to the minus side of the filament and that will eliminate the condenser. It is not advisable to eliminate it with radio-fre- quency, because of the reason that you will find it so much harder to get regeneration started through your circurt and you will lose a lot of the selectivity of the circuit. « * * / enclose samples of yarn. Will they be O. K. to wind G.-R. (Giblin-Remler) coils with? If not, what kind should I use? — Frank L. Pantell, R. 1, Box 57, Muscatine, Iowa. The samples of yarn are a bit too thick. Preferably 4-ply yarn of the same type will do. * * * / enclose circuit that I have tried out. I could only get a loud hum when I used it. Can you tell me what is the trouble and how to remedy it?—E. J. Devereaux Bakersfield, Col. The diagram you enclose has two errors. The first is that the antenna is connected in the wrong place. It should be attached to one end of the inductance instead of to the plate of the tube. The second error is that you have left off the ground connection. It should go to the other end of the inductance, preferably with a slider attached to enable you to get variation of inductance to tune the circuit. The circuit will work if you do this. * * * / am using the set constructed as ex- plained by Ortherus Gordon in Radio World for Ian. 20, 1923. All that I can get is code and whistling. Can you tell me what is wrong? My antenna *s 60 feet long and 36 feet high.— -John Sambenmi, 11924 Lafayette Avenue, Chicago, III. The fact that you are getting code loud and clear is an indication that the set is working. You simply do not know how to tune it. We advise that you put a con- denser in your antenna circuit, with which to tune your primary circuit. Do not burn your bulb too high. This will cause your tube to oscillate too violently and you win get the carrier .wave of the station, but the voice will be so muffled that you will not be able to understand it. Reduce the B current. You may have a tube that does not use a lot of B battery and you may be forcing your tube. » * * You published a hook-up by John Kent m Radio World for Jan. 27, 1923. Will this set work with WD-ll tubes as detector and amplifier, or will it be necessary to use the U. V. 201 for amplification? Can I use U. V. 201 tubes as amplifiers for this cir- cuit?—Edward G. StefFen, 10855 Divine Ave- nue, Detroit, Mich. Yes, this circuit will work with WD-ll as amplifiers. It is not advisable to use the U. V. 201 tubes as amplifiers with this cir- cuit as it would necessitate your using both dry cells and storage cells for the filament current. As this circuit was devised to get away from the bother of using the storage cell, the advantage would be lost. * * * 1. What is the value of condensers in the circuit published in Radio World for Feb. 3, 1923, page 14, by Fred J. Rumford, entitled "A New Amplifying Receiver"? 2. How many turns of wire on the coils L, LI and 12? How are they mounted? 3. Can I use a three-plate variable con- denser in this circuit?— R. W. Nass, Sussex, New Jersey. 1. The two condensers C and CI in this circuit are of the following values: C is .0005 and CI is .0005. 2. The two outside coils, shown as LI and L3 in the diagram, are pancake coils, wound spiral-wise on a piece of stiff card- board or thin fibre and are 50 turns of No. 22 SSC wire. The inner coil (L2) is wound in the same fashion and is 75 turns of the same size wire. They are mounted in such a way that the two outside ones can be swung book fashion, and the inner one is mounted so as to be able to swing verti- cally up and down between them. 3. A three-plate condenser can be used by shunting it across the condenser you use in the secondary, thus making the secondary condenser a vernier. * * * Kindly give me some information as to a receiver that will permit me to receive from 2,500 to 3,500 miles?— O. H. Orr, Foley, Ala. We refer you to Radio World for Jan. 10, 1923, where Mr. Thompson has given some very good reflex circuits. It is possible to do wonderful work with these circuits, but it is impossible to guarantee the range of any receiver to such distances, as much depends on the transmitting station and also on the manipulation of the receiver. * * * Will 45 volts on the plate of the tube (WD-ll) be sufficient in connection with the Flewelling circuit? The set in question is' to be used on an indoor loop. — F. N. Cash, 39 Union Street, Norwich, Conn. In this circuit you can get better results if 45 or even 60 volts are used as a plate voltage. The WD-ll will stand 60 volts without breaking down, so it is perfectly safe. * * * 1. / am using a Westinghouse R. C. re- ceiver with the Power loud speaker. Is this radio-frequency? If not how can I add it to my set? 2. Can I connect a condenser in the an- tenna circuit, and if so will I get any better results? 3. How would the transformers (.radio- frequency) be connected?— J. Frank Dout- hitt. 1. You are not using radio-frequency. It can be added if you wish to entirely dis- mantle your present set. This is not ad- visable as the sets in question have been cal- culated for the best work, and it would entail endless work for yourself to add radio-frequency. We advise building a set such as shown in "Answers to Readers" in Radio World for Feb. 24, 1923. This set is the regenerative circuit, with both radio and audio-frequency. 2. A condenser can be connected in the antenna circuit but we fail to see w,here any additional results can be gained by this unless your antenna is too long to allow you to receive short waves. In this case the con- denser will allow you to get the lower wave stations. 3. They are connected' much the same as the audio-frequency, with the possible exception that an extra tap may be taken off the secondary side which is done in some cases where reflex circuits are used. ♦ * * Can you give me an efficient hook-up for the following apparatus: 1. A. K. variometer, 43-plate condenser, tube (WD-ll), rheo- stat, grid leak and condenser, A batteries, B batteries and phones? I have a set now with these parts but cannot get outrof-town sta- tions.—G. V. Heath, 2116 P Street, N.W., Washington, D. C. We. refer you to the diagram published in Radio World for March 10, 1923, in answer to a question on page 18, by Mr. Hausing. The seven-plate condenser in this circuit is not absolutely necessary, being merely a refinement that will tend to give finer con- trol of the regenerative qualities of the re- ceiver. It can be dispensed with if neces- sary. The rotor of the vario-coupler is used in this circuit as a tickler to produce regeneration and is shown by the coil on the right. ♦ * * / have built the receiver shown m Radio World for Jan. 20, 1923, and described by Mr. Otherus Gordon. Although I have fol- lowed the instructions to the letter I cannot get anything. One peculiar thing is observed. I cannot light my tube when the grid con- denser is in the circuit, but when I remove the condenser and connect the wires, I can light the filament. Will you kindly explain this?— Elijah Collins, N. Y. Mills, Oneida County, N. Y. You evidently have made some mistake. This circuit has been tried and proved a remarkable success. The fact that you can- not light your filament without removing your condenser proves that you have not hooked up the set right We suggest that you re-wire the set, following the diagram exactly, and using a socket made for the WD-ll tube instead of the regular socket with an adapter such as you are using. ♦ * * / have detector and two-stage set. I can- not get anything on the first stage, and can- not hold anything on the second stage. If I attach the ground wire I cannot even hear anything, but when the ground is left off I get everything from New York to Mexico and from Canada to the Gulf, but I cannot hold it. I hear it but it fades out no sooner than I have it m good.— Chester B. Guilty, Box 336, Salt Creek, Wyo. Not having a diagram of your circuit it is impossible to find out what is the matter with it. Send in a diagram with all the parts used marked and we will correct it for you. Address Radio World, 1493 Broadway, New York City. New Orleans Radio Associa- tion, Inc. l^DITOR, Radio World: Referring to your request for the name of our radio club, I beg to advise that the name of our organization is the New Orleans Radio Association, Inc., 2322 Melpomene street, New Orleans, La. The officers are: W. S. Oppenheimer, president; V. Jensen, vice- president; H. E. Faller, secretary-treasurer; L. J. Gallo, publicity manager. I wish to take the opportunity of advising you that at the present time we have 135 members enrolled in our organization. Yours very truly, New Orleans, H. E. Faller, March 10, 1923. Secretary-Treasurer. Digitized by Google

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RADIO WORLD 19 Latest Radio Patents Apparatus for Producing a Succession of Electric Waves No. 1.44S,*a, Patsntad Fab. It, US. Pa WaJtar R. G. Bakar, Scbansctady, N. Y. THIS invention relates to the production of electric waves and more particularly to methods and apparatus for producing a succession of waves which may be modified Bakar's Apparatus for Produclac « Swccaaalaa of Elactric Waves. in accordance with impulses produced, for example, at a controlling or signalling station. Apparatus of this character usually con- sists of a source of electric power, means for converting the energy of said source into current of an oscillatory character and a transmitter for suitably modifying the char- acter of the oscillations. An amplifier for the initial signalling impulses is often used, and this, as well as the oscillator, may con- sist of a vacuum discharge device which comprises an anode, cathode and discharge controlling grid. A suitable source of cur- rent is connected between the anode and cathode, and the current from this source is modified by changing the potential of the grid in accordance with the impulses which it is desired to transmit. It is proposed to provide a single source of current for the oscillator and amplifier. When, however, an attempt is made to change the potential of this source to change the output of the oscillator, as for example when it is desired to increase the distance over which messages are to be sent, it is found that amplifier which is likewise influenced by the changed potential will not operate as effectively un- less a corresponding change is made in the normal potential applied to the grid. My present invention provides for the simul- taneous changing of the potential of the common source above referred to and of the potential applied to the amplifier grid. Wave Meter with Cathode Tube No. 1.44M2S: Patented Fab. 2tL IMS. Patantssi August Lstb, BarUa, Garmany. WAVE meters provided with a cathode tube are well known and it has here- tofore been proposed to provide such meters with a back-coupling whereby the wave meter operates as a sender, and the tunings are determined by means of the telephone in a receiver at maximum receiving tone strength. Under certain circumstances this arrangement has the draw-back that the wave meter, which operates without damp- tween the anode or plate circuit and the oscillating circuit. The arrangement may be particularly sim- plified if the magnets of the buzzer are wound with suitable thin wire and the in- terrupter connected in the anode circuit in such a manner that it is operated by the anode current as a self-interrupter. Indicator for Deviation of Sender from a Desired Frequency No. 1, .«M»jJ"'tat|d Fab. Ml ita •' a Left's Wava Matsr with Catboda Tuba. ing, that is, so as to produce a continuous wave, does not give a tone but must be made audible in the receiver by means of a second superimposed sender or by other s'titahle tone producing means. The invention consists in transforming a normal oscillating circuit, which is back- coupled to an audion tube, into a sounding render by very simple means. The means employed consists in an electromagnetic Ivu/er which is connected in the circuit be- 1F two senders operate jointly at the frequency on an oscillating circuit, a phase displacement of 180* occurs between them. The weaker of the two senders is usually forced into or held in a 180* phase displacement by the more powerful sender. If the wave individual to the weaker sender is now slightly detuned with respect to the more powerful sender, the frequency of the oscillating wave docs not vary but appar- ently only the phase displacement of the two senders with respect to each other is changed. Consequently, a measuring instru- ment provided in a circuit coupled with the two senders will register the variation. If. on the other hand, there is a variation in the wave of the more powerful sender, that is. the working sender, then this will have a corresponding effect on the auxiliary sender, the phase displacement being varied at the same time. The resulting variation in the current may then be used as a measure for the changes occurring in the wave, and the chance in the output of the circuit may be used for correcting the occurring frequency variation. My invention mike* use of these occur- rences for automatically indicating or cor- recting the deviation of a sender from the wave of the desired frequency. The illus- tration herewith Is a diagrammatic repre- sentation of a circuit arrangement embody- ing the invention, and the reference numeral 1 designates an undamped working sender of any well known type, 2 is a cathode tube auxiliary sender, and 3 is a tuned or un- tuned circuit coupled with 1 and 2 in which the measuring instrument 6 is provided. It makes no difference whether the measuring or instrument circuit 3 is periodic or aperiodic. It is even possible to actuate the auxiliary sender without the use of such circuit The momentary deviation from the fre- quency within the phase range may be acoustically determined, a very loose coupling being used. The use of a loose coupling makes possible the employment of Y Scbaffar'a Indicator far Davlatlaaj at Saadsr from a Dasbad Fraauaacy. a mechanically operating measuring instru- ment provided with a scale gaged in a static manner in order to make possible the direct reading of the wave deviations. In order to make possible the reading of both positive and negative variations in the wave of the working sender, the instrument 6 is preferably so adjusted that it gives the -ame indication irrespective whether one or loth senders actuate the instrument circuit. An increase in the reading of the instru- ment indicates an increase in the wave length, and a shortening in the movement of the instrument a shortening of the wave length. The sensitiveness of the measuring ar- rangement may be increased or decreased within the desired limits by increasing or decreasing the looseness of the coupling. In order to make possible the use of the arrangement for the purpose of automatically correcting variations in the wave frequencies within predetermined limits, the indicating instrument itself or in its stead a relay ar- rangement is used for the purpose of actu- ating certain contacts provided for this purpose. Light-Controlling Means No. l.UtMJi Pateatad Fab. 2*, ISO. f Las Da Farast, N.w York City. *THIS invention relates to means for con- * trolling light by and in accordance with sound waves <»r other type of signals D* Forrsf s Maaaa far CoatreUs* Uab*. The ol.jert of the invention is to provide means which arc simple and highly efficient for obtaining exceedingly large light fluctua- tions by and in accordance with sound waves or other t\pe of signals. A further object of the invention is to provide a device which may act as a source of light, and which is extremely sensitive to sound waves, or, in other words, the light irom which will vary greatly in accordance with relatively small current variations in the li'cuitt connected therewith. Digitized by Google

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20 RADIO WORLD New Records of The DX Nite Owls Gets Unusual Results , From Norman T. Shideler, Blonmtnfton, Ind. I HAVE been experimenting with wire- less for more than two years, and in that time have made a number of receiving sets which have worked satisfactorily; but in the last few weeks I have constructed a set which gives unusual results, and which I think will be of interest to other radio fans. My set consists of a 23-plate condenser, a home-made vario-coupler coil, a S-plate variable condenser, a WD-11 tube, and the other things which are necessary in all tube ' sets. My coil is 4f& inches in diameter and is wound with 109 turns of No. 26 D CC wire. The first 25 turns are untapped, then a tap is taken off at every twelfth turn, making eight taps in all. The tickler coil is wound with SO turns of the same wire, and on a three-inch tube. My hook-up, using the above instruments, is shown in the diagram, together with the layout of the panel. The 23-plate variable condenser is used in the aerial circuit. The S-plate condenser may be used either as shown in the draw- ing or across the tickler (shown by the dotted line). It works well in either place. In using this condenser I am able to get finer adjustment, and it also seems to add to the regeneration. I also use a phone condenser, but it is not absolutely necessary, as the tube does not require so much current when the condenser is used. The amount of B battery current needed depends ' l <-pHE Editor of RADIO WORLD wfl bo drawn carefully m black Ink or poncU from tho "DX Nits Oris" who in records with a view to nnbHoMnj Send book-up* of year sots, they contain sanesthsa* also, toe nam— of tho vsrls— apparatus you are aslng. Make your letters brief and Writ* on one aid* W the nap The letters bshod m the RADIO WORLD. speaker. The set has a wave length of from 200 to 1,000 meters. I hope that this may be of use to some of the radio fans. Uses an Humble Crystal Set From Bill Keating, Minneapolis, Minn. HERE'S another little DX record for a humble crystal set. On a night not long ago I nicked up the following long- distance stations, which I heard clearly: WOC, Davenport, la., 275 miles; WHAS, Louisville, Ky., 600 miles; WCX, Detroit, Mich., 550 miles; WGY, Schenectady, N. Y., 1,000 miles; KDKA, East Pittsburgh, Pa.; 800 miles; WDAF, Kansas City, Mo., 475 miles; KSD, St. Louis. Mo., 500 miles; WLW, Cincinnati, O., 600 miles, and, last, but far from least, WOAI, San Antonio, Texas, 1,200 miles, which, I believe, is a record for distance with a crystal. The Has Heard 150 Stations From Leon A. Mean, Minneapolis, I SEEM to have had exceedingly good results on my three-circuit set, using two steps of amplification. Most of my material is Atwater-Kent or Michigan, and I assembled the set I have heard 150 stations and a mileage of 15,170 miles in one evening. The stations heard on this evening were: CFAC, KDKA, KFAF, KFDL, KSD, KYW, WCAE, WCAS, WCX, WDAF, WEAF, WFAA, WGM, WGY, WHA, WHAZ, WSZ, WLAG, WLW, WMC, WOC, WSB, WWS. The farthest stations received are : PWX, Cuba; KWH, Los Angeles; KGI, Berkeley. Cal.; KUO and KDN, San Francisco All the stations come in clear. On a One-Tube Set From William Hansen, Astoria, Lonr Island T WOULD like to submit my receiving A record for a one-tube set, using a 43- plate variable condenser, vario-coupler and two variometers and Brandes phones. The following stations were received loud and clear: WHAS, WHAI, WJZ, WEAF, WOR, WHN, KDKA, WBAN, WGY. KSD, NOF, WAAE, WBS, WAAM. WDAP, WJT, WMAC, WBAX, WSB, WOC WGM. WBAY, WWJ, WGI, WHK, WIP WRP, WTAX, WEAP, WJAS, KYW. Fit- 1- Hook-up used by Mr. Shideler Fif. 2. Layout of Apparatus, as arranged by Mr. Shideler entirely on the tube. I have found that it varies from 13J4 to 25 volts. I have had unusual results with this set. Following are the stations I have heard: KDKA, KHJ, KSD, KYW, PWX, WAAC, WAAF, WAAP, WBAP, WBZ, WCAE, WCX, WDAP, WEAF, WFAA, WDAF, WDAJ, WFAV, WGI, WGM, WGY, WHK, WHAZ, WIP. WJAF, WHAS, WHB, WJAP, WJAX, WLAG, WLAL, WLW, WMAF, WMAK WMAQ, WMAT, WMC, WOC, WOR, WOS, WPA, WQAA, WRAO, WSB, WSY. WWT, WDAV, WMAC, WLK, WBT, WGF, WCK, WGR, WHAB, AVZ, WOAN, NAA, CFCA, CJCG. Under ordinary conditions I can pick up any of the above stations. The larger stations, such as WWJ. WGY and KDKA. come in so loud that I can use a loud other stations I get regularly, but that is the only time I have got San Antonio. They came in very distinctly. The above stations were picked up while I was testing one of my sets, and the remarkable part about it is that they were all tuned in within less than ninety minutes between the hours of 7:30 and 9. Several other fans using sets like mine have had equally good results. California Records From Norman West, Lanrndalo, Cal. "\X7'ITH a detector tube only I think I » * have some records as far as they go: WBAP, Fort Worth, Texas; WOC, KYW. KSD. WOE. WEAB, WNAC, WQAA, WDAF, KGU. WSY, KFC, WOS. WBAV, WOR, SPG, 9CXP, 8MK. WDAT, KOP, WBT, WLK, WOS, WOO, WGR, WMAT, WFI, WMAW, 1RI, ILL. I have also received about 50 amateurs. I don't think my record is bad for a home- made set. Looks Good to Us From Nite Hawke, Oshkosh, Wis. I READ about your new game of radio golf in the Feb. 3 issue. Here is my score, done with a Grebe CR-9. Starting at 7 p. m. I heard 21 stations till I stopped at 9 p. m. The total distance covered was 11,800 miles, or an hourly average of a little more than 5,900 miles. I did not stay up to hear the far western stations, such as KHJ, KYG, KDYS, and KDZR, which I Usually hear. This is some DX record, is it not? All the stations were more than 200 miles awav. Digitized by (Continued on page 21) Google

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KADIO WORLD 21 DX Nite Owls (Continued from page 20) A High Aerial Is a Help From L. Cochran, Colorado Sprls**, CoL HWING been an interested reader of your DX records as published in Radio World I submit one from Colorado Springs — "the city of sunshine, at the foot of Pike's Peak." Using a standard hook-up, detector and two step, honeycomb coils, aerial 150 feet long, of an average height of a littK; over 50 feet, the following stations have been received since last September: AS6, 6XB, 6XY, DN4, DDS, KDC, KDKA. KDN, KDPT, KDYL, KDYS. KDZQ, KFAD, KFAF, KFAN, KFAY, On* of Mr. Cocfcraa'a IS-Foat KFBB, KFBC, KFBK, KFCL, KFBV, KFC, KFCK, KFDB, KF1, KGG, KHD, KHJ, KJS. KLZ. KM J, KNI, KOA. KCB, KOP, KFDL, KPO, KOY, KSD, KUO. KUS, KUY. KWH, KXD, KYJ, KYW, KZN. WAAB, WAAC, WAAH. WAAK. WAAL, WAAP, WAAO. WAAW, vVAAZ, WBAP, WBF, WBL, WBZ, WCAL, WCAV. WCAZ, WCK, WCM. vVCX, WDAF, WDAH, WDAJ, WDAO. WDAP, WDAW, WDAY, WDV. WEAB, vVEAF, WEAH, WDAZ. WEAY, WEY. WFAA, WFAC, WFAR. WFAS, WFAT. vVFAV, WFO, WGAB, WGF, WGY, vVHA. WHAS, WHAZ, WHB, WIAR, .VIAS, WJAD. WJAM, WJAN. WKAA, vVKAL. WKN WKY. WLAG, WLAJ. vVLAL, WLW, WMAB, WMAD, WMAG. rVMAH, WMAJ. WMAT, WMAY, WMH. vVNAD. WMC. WOAA, WOAI. WOC. A'OH, WOI. WOK, WOQ, WOR. WOS. ►VPA. WPAC. WPAM, WPE. WQAQ .VRM. WRR, WSB, WOAZ, WSY. AW J. CFCA. CFCN, CHBC, CHCA, CHCQ. :.TCG. CKCK. This list comprises 144 stations located in '5 different states and four provinces of Canada, and figures a total of 110,000 miles. \ll the states represented are west of the Mississippi River with the exception of Nevada. On a recent night I distinctly listened to the test programs broadcast from KHJ, Los Angeles, and WOR, Newark. N. J. This test was started by KHJ at 11 o'clock p. m.. Pacific Time, and was answered thirty minutes later by WOR at Newark. This was at 12 midnight here, and even at that hour several stations could be heard — for instance, the Drake Hotel. Chicago. The Kansas City "night hawks" were on just a few minutes before KHJ started, and Stamford, Texas, was on during the test. This record is not the best one in Colorado Springs, as several of the fans have records that include Havana, Cuba, a station I have never been able to pick up. I am enclosing a picture of one of my aerial poles. This pole is 73 feet to the top, and is made from old iron pipe, put up by one man without other help than block and tackle. The pipe was telescoped before raising, so that, at the time it was erected by the eave of the house, it was only 24 feet in length; then the inner or first joint was hoisted by a "gin pole," bolted to the second joint, and so on, like lengthening a telescope. The radio engineers have reported that Colorado Springs is handicapped in recep- tion owing to a high magnetic field which practically surrounds the location, and we find that reception varies, especially from the north and east; but from the south the stations seem to come in pretty regularly. Determining Longitude by Radio From E. D. Ball, Spuria! Hf, S. C ^JOT long ago I determined my longitude J- x by use of the time signal from Arling- ton via Pittsburgh. This may be of in- terest to some of the radio fans. The star Pegasi was used. The star's time of transit was computed in local time. The mean time watch was used to get the standard time of the star's transit. The correction to watch was taken by the wire- less time signal via Pittsburgh from Arling- ton at 10 P. M. The watch face reading of star's transit was 10 h. 3 m. 22 s. The correction to watch was 10 seconds fast... —10s. The standard eastern time of transit was 10 h. 3 m. 12 s. The computed local time was 9 h. 35 m. 41 s. The difference is the longitude from 75th meridan 27 m. 31s. Five hours added gives the longitude west from Greenwich, which is S hours, 27 min- utes. 31 seconds west. This checks less than a second of the same taken by Western Union wire. Having a small astronomical observatory enabled me to do this, in connection with my wire- less set. Weather Sometimes Interferes From Jobs R. KmMt, Iowa City. Im T HAVE been a radio fan for almost one *■ year now, and sure do like to experi- ment. I am usintf a WD- 1 1 tube. The greatest distance I ever heard over was I.os Angeles. 2000 miles awav. I eet WOC WHB. KDKA. WGF. and many others. If the weather is just richt I can get WGY f'ne. WIIAA. a local station, is a very hard station to tune out I can usua'lv tune them out unless the wea'her is exrrpt-oml'v bad. I ohta:n be.t results on the 12-vnlt tap of my "I!" batterv. As I do not have a ft.vi-.lt tut>e I do n.'t know how 12 volts would work on one ( ( Vxi.'iMii.-c/ on pti;t 24) X/I)is Combination TO own a Rood receiv- ing set without Mag- navox equipment, is like having your house prop- erly wired and then using only small, feeble candle- power lamps in the sockets! Whether placed In the aver- age living room or large dance hall, Magnavox Radio floods the desired area with clear, resonant music orapcech — its volume perfectly controlled from the Magnavox Power Amplifier constructed spe- cially for it. Combination R - 3 Repro- ducer and 2 stage Power Amplifier I a* illustrated i. R-2 Magna vox Reproducer with lS-inch horn: the ut- most in amplifying power, for store demonstration, large audiences, dance halls, etc. - R-3 Magnavox Reproducer with M inch curvex horn: ideal for homes, offices, etc. Model C Magnavox Power Amplifier insures gttting the largest rx<»sible power imput for your Magnavox Reproducer. 2 stage 3 stage '.«.:/- .». i PraoWri c ** Kr KjJ c4 I ... JUalm r.«r,«.**r« The Magnavox Co., Oakland. California Nr» Yortu J70 Seventh Avenue J»wt.W e»«e MAmvox Tflu- fbwcrJIinplifier and Reproducer Supreme Digitized by Google

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22 RADIO WORLD Advertising Rates : Display, $5.00 per inch, $150.00 per page. Radio Merchandising Classified Quick-Action Advertising, 5 cents per word. Telephone Bryant 4796 New Radio Firms (The new firms and corporations men- tioned in these columns con be reached directly or by communicating with the attorneys, whose addresses are given when ever possible.) Domestic Supply Company, Dept. 28, The Broad- way Market, 19th afreet and Broadway, Oakland. Cat, household goods and electrical appliances and supplies. Electric Novelty Shop, 4th and Market streets, Logansport, Ind. H. Levy, proprietor. American Electric Sales Co., 632 Baronne street. New Orleans, La. Nicholas Bros., 123 South Winter street, Adrian, Mich., are adding; radio supplies to their business. Kinley Radio Co., 33 Elmhurst avenue, Detroit, Mich. United Electric Stores Corp , New Market. N. J. Samuel Eisemann and others. Seattle Lighting Fixture Co., 617 Fourth avenue, Seattle, Wash., is adding radio supplies to the business. D. X. Radio Corp., New York City, $5,000; W. and M. Scadron, H. Jaotons. (Attorney, L. Sca- dron, 149 Broadway.) Burrows Magnetic Equipment Corp., develop patents, $90,000: C O. Assmus, T. Irving Potter, East Orange, N. T.j Harrison H. Pierce, New York. (Julian Walker, Wilmington, Del) Municipal Products & Electric Co., Buffalo, N. Y., $15,000; A. A. Aaron, C Dautch. H. A. Kulowski. (Attorneys, Aaron & Dautch, Buf- falo.) Elliott Electric Supply Co., New York City, in- creased capital from $5,000 to $1000,000. Will-Fred Electric Manufacturing Corp., Queens, $20,000; W. O. and B. A. Feldmai, E. F. Calnes! (Attorneys, Mann & Buxbaum, 886 Broadway, Brooklyn, N. Y.) Merrick Electric Co., Queens, $10,000: T. L. McKeown. E. E. Breiling. (Attorney, T. Breiling, Holhs, Long Island.) Super Radio Corp.. Wilmington, Del., supplies. $1,000,000. (Corporation Service Ca) ' Marks Radio & Electric Co., New York City. ¥'000; Li",rkl- B- Wertheir. (Attorney, H. fc Adams, 220 Broadway.) Long Island Electric Service Corp., Queens make wireless apparatus, $9,000; B. LaDoint. T V. Miller, W. WTCaulneld. (Xttorn^W. £ Kennedy, 47 Cedar St., New York City.) Radio Exchange, New York City, $6,000; L. Feldman, B. Gleichman, F. Golding. (Attorney, M. L. Kane, 50 Court St., Brooklyn, N. Y.) O'Connell Electric Co., Rochester, N. Y. in- crease of capital from $10,000 to $50,000. Maceur Elettrical Supply & Radio Co.. Man- hattan, $5,000; W. Hurza. J. McQueen. (At- torney, H. Schapiro, 261 Broadway, New York.) How Radio Helps Shorthand Students VERY day brings to light another use for radio broadcasting. It is now revealed that students of shorthand and typewriting are picking up addresses out of the ether to increase their speed at the type- writer or in writing shorthand symbols of the speaker's words. Those who have had to rely upon the patience of a member of the family or a friend to read to them while they dashed down the dots, dashes and curves can ap-- v the advantage of radio dictati' • Radio Stocks (Quotations as of March 7, 1923, fur- nished by Frank T. Stanton & Co., 35 Broad Street, New York City, Specialists in Wireless Securities.) Stock Bid Asked Am. Marconi Stamped ... 5c 7c Am. Marconi Unstamped 5 7 American Tel. & Tel... \24y2 125 Canadian Marconi 2y3 3H De Forest Radio 7 10 English Marconi com 11 15 English Marconi pfd \V/t ISyi Federal Tel. Calif 6 6yi General Electric 185 186 Hennessey Radio Pub... 9 11 Manhattan Elec. Supply. 55J4 56 Marconi Int. Marine 9 10 Mackay Co. com 116 117 Radio Corp. com • 4 4% Radio Corp. pfd V/t 354 Spanish Marconi 1 3 Western Union 115 116 Westinghouse E. & M... 64J4 64& Satirizes International Radio A FACETIOUS correspondent writes this letter to the New York Times: "The attention of American reformers should be directed to the wave of moral turpitude into which the English have either drifted or plunged during the last week. Children in the British Isles are being kept up until 3_A. M., London time, to hear bed- time stories by radio, after which their elders begin orgies of song and dance that continue without cessation until 7:50 A. M. Beyond the probable deleterious effects on the English, it is difficult to estimate the number of cases of shattered nerves sus- tained by American radio amateurs in trying to hear the London revelry on this fantastic schedule." Wireless Shares Boom Following the announcement by Pre- mier Bonar Law that licenses will be is- sued to the Marconi's Wireless Telegraph Company, Ltd. (English Marconi), to operate a large central station by which they can keep in constant communication with the world, similar to the Radio Cor- poration's station on Long Island, shares of all the companies have been in great demand. Radio Corporation common sold on March 6, from $3Jti.i at /TTT/rrTr... 77. .« FILAMENT RHEOSTAT vitb ill* «a|. vslus. 11.80; sssslsl at.. .7.. 77. .15 Pet.ntlem.tsr wttst kaib; vslus sl.78; we- "" g I.tl *!S3SF$* wtos/ll-is: Doubls slrtalt; vslus. OQs; ssassVl^at"": Af THREE. INCH DIALS— Ulbreakaala— SM rwktlng wesssltlsa— blgb Sslsh- --^ rhMitats and HALS — Saavs «sslaa pstsnwssnfr; spsslaf.. EXTRA SPECIAL— Tslspbsea Hssaseti: 11.00 vslus; rsdaw ^ggSijggiB ■ ■ BH E08TAT* ' sooo i ts. . . 3.25 ■31 ■it I.M 1.7! REINARTZ C0IL8— Valss. $8.80 ... AyjJ!!,N^iM^L0.u.B.!PEAKIN0 HORN— Ntck«l Pl»t«d; List 80.00 ».75 AUDIO-FREQUENCY TRANSFORMER — For ass with W.D.-ll Tubes; List 14.50. 2.71 Everj/ article advertised above U guar- anteed both by the manufacturer and bii us— Mail orders filled immediately— transportation PREPAID on all orders of J.i.OO or over east of the Mississippi River. All others include postage. Digitized by Google

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RADIO WORLD 2 Relative Advantages of Single Circuit and Double Circuit Tuners j RIOR to the introduction of radio broad- casting, the ordinary type of radio re- :iver used by the amateur was of the juble-cireuit or three-circuit type. Because e radio amateurs were well versed in the « of these instruments it was not difficult r them to use these tuners and they took ide in their skill of operation. However, len broadcasting was initiated, the need r a simple tuner device that could be ed by the layman was considered neces- ry and a single-circuit tuner was devel- ed. On account of the simplicity of this w tuner and in view of the great num- r of broadcasting stations operating at the :sent time, confusion resulted concerning : efficiency of this tuner. Interference of 0 broadcasting stations is the cause of uble in the use of the single circuit tuner. The interference sometimes encountered radio broadcasting reception is primarily troblem of broadcasting transmission. It 1 be eliminated by the enactment of suit- e government legislation that will enable ve- lengths other than 360 and 400 meters be assigned to broadcasting stations. No eiving tuner, whether it be of the single double circuit type, will prevent two ■adcasting transmitting stations operating ntically on the same wave length from ting up interference in the receiving set, ess the signals of one station are of suffi- nt intensity to drown out those of the er station. Two broadcasting stations ^rating on nearly the same wave lengths 1 produce an audible note or "whistle' in receiving apparatus, which no tuner of ter the single or double circuit type will ninate. The cure for this problem is the ignment of wave lengths to the trans- ting stations of sufficient separation so not to produce an audible note, rhe single circuit tuner will enable the ener to differentiate between two local adcasting stations by erecting an antenna over IS feet high and 15 to 20 feet in gth. It has been conclusively demon- ited that a low antenna is more selective n a high antenna. The selectivity on a en antenna can be increased by an ad- onal series condenser between antenna ! tuner. electivity in regenerative receiving sets primarily a function of the amount of sne ration. Two local broadcasting sta- i9 on different wave lengths will often in- ere with one another on either the single double circuit receiver, but this is due to overwhelming power of the transmitter ch causes the apparatus to function by •k excitation and respond even when not irately toned to the transmitter. It has i demonstrated beyond all cavil that in- erence set up by two local stations can eliminated on the single circuit receiver in antenna, as described above, he ordinary regenerative set with the ble circuit tuner gives from 20 to 50 per reduction in signal audibility over the le circuit with the same number of tubes the same general circuit In other ds. stronger signals will be obtained, in distance reception, from a single circuit han from a double circuit set [Tie Advantage* of Two Antennas it those who have interest in long dis- e reception, as well as local reception who experience difficulty in obtaining necessary with the low antena owing to •etng shielded by buildings, etc., it is ctimes advisable to erect two single wire ils. one for long distance reception — h may be of any wave length up to 150 and the other for local reception — :h is the small one previously described. small antenna enables one to difTcrenti- hctween local signals, while the larger ma can be used for long distance work ■ trie local stations have discontinued, any users of broadcasting sets are now installing two antennae — a long one for long distance reception after the local stations have closed down, and a small one, or an indoor aerial, for local reception. The indoor aerial may consist of 10 to 25 feet of lamp cord concealed behind the picture moulding, or a piece of No. 28 wire stretched across the corners of the room. Listeners located up to 15 or 20 miles from a broadcasting ' station can often obtain all the signal audi- bility necessary for local work by concealing the antenna under the carpet of the living room or the library of the home. The foregoing are technical points which will stand the closest analysis. Speaking purely from the commercial phases of the matter, the single circuit tuner is, without qualification, the most suitable for the novice, that is, for the user unskilled in the art; for generally, the multiplicity of knobs involved in the operation of the double cir- cuit tuner places them beyond the stage of practicability for the non-technical public Single circuit tuners were designed pri- marily with the idea of providing simplified operation, and as such, they enable the novice to obtain results which can only be secured from the double circuit tuner when the user possesses an intimate knowledge of the technicalities of the art. Comparing collectively the advantages of the two types of tuners, it is clear that the single circuit tuner is by far the more useful to the average member of the family, as it enables him with a minimum number of ad- justments to pick up far distant or local broadcasting stations. Usually the distant station can be found on the single circuit tuner several minutes before it can be lo- cated on a double circuit tuner, to say noth- ing of the increased audibility which the single circuit set provides. For long distance reception, it is prefer- able in every case to install an outdoor an- tenna in a free open space keeping the lead- in away from the building and bringing it as directly to the receiving apparatus as possible. The antenna is preferably kept at the maximum distance from the trolley car lines, power lines, trees, buildings, etc, whereupon a marked increase in selectivity and in signal strength will be obtained. FREE CATALOGUE Make D X Records With D X Supplies This Catalogue should be called "Recipes for Long Distance." It was written to help ama- teurs pull in the most distant stations. D-X-Radio Company on instruments built for Dis- tant. If you want to jump States or reach over mountains you must use the proper equipment. Our instruments do the trick. For Free Catalogue Write! D-X-Radio Company 123 Liberty St., New York City Fifty-two issues for $6.00. Sub. D M oatteaad, PHONO VARIOOOUMIM via Imrtm SS.S* Oaytea Tm S7 • la aalt Ill IS* Dtejraa Silt Waaa4 ... J Brmaatea ».»• VARIOMETERS Faaarate S.4J Oaytea Faa I* aarwtak S.7S Am* I. Haraaak ISM aaa Spaata! 4.29 frtt Rakallte 7 POTENTIOMETERS I. iM aaaa 29* ateaa I.7S • Mi S.N RHEOSTATS) Cattar-Haaaar VnK Oattar-Haataar Naa Varater Safaljitla RAKELITE CONDENSER*. II alato. Raafla Staraa 15 *tate. aula Btaraa 41 plate. Raaia atarw IS Ptete. Water 4S ptete. V "rater U. a Taal tS ptete. Flkra aaaa 43 Plata. Flkra aatea RCCCIVINS SETS DaFaraat Rattekaaa Oatoatar DaFaraat 2 Step* AtepllSar Aaaa 2 Step* Aapllaar aaabaaa Orteater aaaaaaa I Slip AtepllSar Saabaaa 2 Step AtepllSar (Caaplata «ltk Tate*. Battery. ■ rtenn. Atrial, ate.) BATTERIES Starapa. Eaarrady, 50 Atea Stmft. Evtrtadv. 00 Atea Btaraaa. Em«ady. 110 Aap "B" Bat.. Evrrraay. 22', V.. SaaaJI .. SI. IS . . S.7S .. 4.IS .. 4.04 .. S.SS .. 14* .. S.I* II I. M .. IS.** .. 4 9 It .. 4 J 00 .. 79 00 129 *• Rattary. 114 00 IS %0 II (10 l.'O W, V.. 4* V., > Call DaFa S Call Lar«a Laraa. M0UNTINA8 SI (DaFaraat Oalte la ateaa) MISCELLANEOUS .91 .15 10 (0 50 25 at .09 .00 .71 05 s .'»•' '.«• .9*. .9*. .79. I I KunKrmm Muttiranca Variormiplrr. I.'.o to :imM> M*(«»ra. (omplftr with Solid llakrlllr- Varl..m tapaaa G'i4 Laaka. Fraakaaa Paatr Caaaaatara. All Site! Aataaaaa Wira lavulafara .... . . Cryitali loll Ool> S I.a}rr. Bank Wound, ttllk *Ali» (llook-un I'umiahad aalth Coll) S.1 1.1 .22 .10 7J 00 .19 • 0 01 00 '0 .10 7* .15 S'-U-rt ynur |rf untf I. -r , V bl ,'"T tj'irr,. HVII do fNr rr,f. SUNBEAM ELECTRIC COMPANY 71 THIRD AVE. (Bet. 11th and 12th Sta.), NEW YORK f arm LlchUag Plant a at Barxala rrtrra. Digitized by Coogle"

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24 RADIO WORLD PATENTS ■rtssotty praerso. Trans Saraa nUM la lk> t. aud sbroed. Csn at FREt AOVICt, Tilt. • '-".tXMtNUFACTURtRS Bf PATENT COjcl ;pT"520 f;fth AVE Nt W Y ;;pk RADIO MAILING LUTS I1.4M Ml* Diian, ss»srlaa 0. a. ay I i .* iVnatU mOi: iXiiim o X mi* ' " " " 1.7*7 Ml* taito 1 latin. •»»» ttMt* per Met , m T5«g immss, wikt U7 lla «iw aJw eaj mm nets, mt int....... ...t4.M M.Mt Ml* Aantsars eat] MM— n *f Mk let W. AOAM STRUT MIMM. IU. RADIPHONO ADAPTER $2.00 6&s£ S5i-i,i»™JSl > IrtrulaV, — — i IISPnK •U.. u a wwtarfol loud ThU tort*d MBl icy rtrfundaxL JIM Industrial gale* EsuruMerlne; Co •71 Bras* Strsst. Nteark. N. 1. PKonf, Markrt 9023 DX Nite Owls (Continued from page 21) A War Veteran Reports From Albert ft. Chmmpiiu, tt Maple Ava* Westerly, R. L AS I have not seen any records listed from Rhode Island lately I thought you might desire to publish my late tests. I am a commercial operator, having served through the World War as a radio man, and had some interesting experiences. I have a detector and one-stage, using 50 feet of phosphor bronze wire strung around the baseboard of my room. I have received the following stations remarkably clear: WGY, KDKA, WEAF, WNAC, WBZ, WGI, WWJ, 1,000 miles; WOT, WHA1, 1,200 miles; KYW. 1,000 miles; WOR, WAAM, WJZ, WIP, WHAG, WJAR. Besides 1 have copied several CWS and amateur sparks. On 600 meters sparks have been copied as far south as NAT, New Orleans. I think this is good for inside antenna. Receives on Detector Only Fran Lang Spall. Bontfay, Fla. I HAVE been reading Radio World for quite a while, and thought I would send my DX work in. I am using the single-circuit hook-up which was published WALCON Radio Frequency Transformers Brings in distant stations on a loop— perfect reproduction. Na distortion. Awarded Certificate of Excellence by N. Y. Ere. Mafl, THE BEST YOU CAN BUY WALCON Transformers are tested and ruer.nteed. Particularly adapted for use with W D. -11 tube*. Four new hook-ups. including a new refli charge with each transformer. Price, $4.00. We pay postage. Dealers' and footers : Write for our backed by national Manafactared by THE RADIO CENTRE, 2 West Broadway, N. Y. DELICATE SOLDERING Bwtk Use muntmctm*** aasd a* problem am all tin* warm, la Nastily aelved by Uv« lmatmnmit Mortracted for this parti cmlar parpose. THE POST SOLDERING IKON Platinum Heating Unit — Interchangeable Tip* — Universal Cnrrent (LeVja* and BmaU) $6.00 Yaw Dmmt mt Write Awarded Cwtlteto mt * Isallll. M. T. BVeatef Mail fUaUa UatitwU POST ELECTRIC COMPANY, (Ph. SOS) 30 E. 42**. Sl, Um 1mA in Radio Woklo of January 27 and find it a fine one. The greatest distance I received was about 2.200 miles— KGW, Portland, Ore. KHJ comes in regular. Others are : KFI, KFAf , WAAL, KYW, WDAP, WJAZ, WLK, WOI, WOC, WHAN, WHAS, WIAR, WBAM. WDAN, WWI, WCX, WWJ, WOS, WDAF. WHB, KSD, WJZ, WOR, WEAF, WGY, WHAZ, WBT. WLW, WJAX, WBAJ, WKAK, WKY, WLAL WFI, WIP, WOO, KDKA, WHAF. WMC, WMAM, WFAA, WDAH, WBAP, WHAB, WEAY, WKAL, WOAI, WJAD. WAAK WSB, WGM, WDAJ, WHOA and WSY. These I did not get: Auburn, Ala.; Greenville, S. C.; Knoxvflle, Teau, and one in Cuba I couldn't get, call or town. This is my 1J4 months' record, being a total of 65 stations in 25 states and Cuba. All these were received on detector only. A Good Hour's Work From Gene UUemrer, Rock I eland, ID. I HAVE a record of 7,500 miles in one hour. This is only the second time I have attempted to time my mileage. I get all my stations regularly but one. That is Troy, N. Y. I have two friends who listened in who will answer -for my mileage. I have a three-bulb set. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway, New York City Please send me RADIO WORLD for months, for which please find enclosed $ SUBSCRIPTION RATES: Single Copy J .15 Three Months 1.50 * ' Six Mont! - 3.00 One Y. Foreign P an Post- He Likes Nite Owls Records From Maurice T. Dubei, Buffalo, N. Y, HAVE been reading with interest the "DX Nite Owls'7 records in Radio World, particularly regarding crystal de- tection. Mr. Keating' s record is particularly good. Here is my contribution, using a crystal set and no amplification : KDKA KOP, NOP, WBAY, WBZ, WCK, WDAP, WIP, WJZ, WOR, WEAF, WEAI, WBU. WGY, WHAS, WHAZ, WIAR, WJX, and WOC. Farthest air line distance, St. Louis, 760 miles. If you want details of my set will be pleased to furnish same. Time, experi- menting, patience, a good piece of galena and good results can be had. Had ten of the above out-of-town stations in one evening. Rapid Fire Work From J. C Bradley, Justin, Tax. I SEND herewith my DX record for a recent night. I speeded up the old flivver some. Total time worked, three hours, fifteen minutes. Mileage, 19,330. Average, 5.944 M.P.K. KFFQ, 6:45 p. m.; WGY, 6:50; WHA. 7:04; WMAK, 7:10; WMAU, 7:15; WHAS, 7:30; KDKA, 7:35; WHB, 8:00; WSB, 8:02; WMC, 8:10; KSD, 8:20; WOC, 8:30; WLK 8:40. Closed down until 9 :45 p. m. WJD, 9:50; WMAQ, 10:00; WDAP. 10:07; WTAN, 10:10; KFI, 10:15; WLW, 10:22; WGF. 10:23; WOAI, 10:24; WLAL. 10:30: WCX, 10:43; KPO, 10:44. Signed off. 10:45 p. m. I did not count eight stations closer in— three each at Waco and Dallas, and two at Fort Worth. Texas. Some of these were on the air all the time from 6 p. m. until 10:45 p. m. A Home-Made Record From William M. Jackson, WOacsa, Otda. T HAVE been reading the DX records in * Radio World for some time and would like to submit mine. I have a »h~--~-«iii tuner, detector and two-stage ampnner, which I built myself. My aerial is a single wire, 115 feet long, 20 feet high on one end and 25 feet on the other. On a recent night I received the following stations : WDAP. WDAF. WOC. KDKA, WBAP. WMC. WCX, WLW, WGY. WOS, KLZ, WFAA, WSY, KFAF, WOI, KSD. WLAG. WSB, KGW, KFDL and KFI. This makes 21 stations in 15 states. Mr longest distance is KGW, Portland, Ore. I have got 26 states so far. but expect to get more. Digitized by Go C7 Vlt

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RADIO WORLD 2! Grain Prices Broadcast From Chicago Every Half Hour THE latest method of broadcasting grain price quotations by radio from Chicago is an important service to the farmer, and is thus described by the New York Times: It is 9:15 in the morning. The spacious trading floor of the Board of Trade is astir. Traders are changing from street coats to light jackets before entering the pits. Messengers are scurrying about, hands crammed with order blanks. On the stroke of 9:30 a gong sounds. Overnight orders to buy and sell grain and produce are rapidly executed. Buyers, representing the consumer, seek the lowest price. Sellers, representing the producer, seek the highest price. The figure at which these two forces meet represents world values. Over at one side of the trading floor is a man in a glass cage. He is in direct com- munication with a powerful radio-sending station. The opening prices are registered. Without the delay of a second these are transmitted to the radio-sender at the station on top of a large Chicago hotel. Far out in the grain belt, hundreds of miles from the sending station, is Jed Smith, a farmer. He wants to know whether the time is opportune to ship his grain. He steps to his little radio-receiving set, tunes in to the 360-meter wave length, and what he hears runs about as follows: "WDAP speaking. . . . Opening prices on the Chicago Board of Trade. . . . May wheat . . . one twenty-three and a quarter. . . . July wheat . . . one fifteen and a half ..." Then follow other quotations on gram* and provisions, with important market news comment. At half-hour periods from the opening of the market until the close at 1 :1S the quotations are broadcast, and thus made available to a legion of farmers and dis- tributors. It is a milestone in marketing progress. Hardly had the radio become practical when its value in the dissemination of price quotation was recognized at the center of world grain trade. A test period of broad- casting was opened. In a short time hundreds of letters and telegrams came pouring into the Board of Trade from scores of cities, towns and villages com- mending the service. They came not only from farmers, but country elevators, shippers, banks, business houses and educa- tional institutions that use the quotations in class work. Advices showed that, in Illinois alone, almost 500 towns and villages were using the quotations. Hundreds of farmers not in easy communication with towns obtained small radio-receiving sets for home use. Reports from other states told a story of similar interest. It was then that the Board of Trade determined upon a permanent, continuous broadcasting service, and recently the Board purchased outright the big radio-sending station WpAP, on the Drake Hotel. "The imagination falters in measuring the full significance of radio," commented Henry A. Rumsey, Chairman of the Board of Trade Radio Committee. "Forces of no less promise have written strange history. In the grain and produce market alone wonders will be accomplished. It will not be long until the farmer in the field follows the course of his daily market as closely as the merchant on the trading floor. And that is precisely what the Board of Trade wants. It has spent a fortune in an effort to give the farmer first-hand information on the ever-shifting world supply and demand. The grain trade is determined to aid the farmer in this end and_ in every other manner commensurate with sound economics." "It is our intention." said Robert Mc- Doueal, former president of the Board, speaking at the formal opening of the new station, "to give the entire radio public the official prices and other valuable informa- tion in connection with all commodities handled through this channel, thus serving the public from the farmer to the consumer. We hope to broaden our acquaintance and to demonstrate our contention that the Chi- cago Board of Trade is an open book that 'he who runs may read.' "The complete ownership and operation of l!.e station will bring to our association, aj h, no financial return. But it will work to the mutual advantage of the mem- bers and their world-wide clientele. It is indeed a step forward in our endeavor to acquaint the public in the grain business and also with the operations of the world's greatest- grain exchange and the largest in- ternational enterprise in the Middle West." The extent of the territory covered by the radio grain market service has not as yet been fully determined. Those in charge say, however, that a comparatively small radio set is capable of receiving these reports in any state in the Union. Two thousand five hundred price quota- tions on wheat, corn, oats, rye, barley, pork, lard and ribs are issued from the Chicago Board of Trade on every business day. As Chicago is the largest grain exchange in the world the quotations are of vital interest to every one concerned with the production or distribution of these commodities and to persons in scores of related industries. The radio has placed at the disposal of the farmer all salient features of this machinery of crop information and market- ing. It has virtually placed him on a foot- ing with the most enlightened merchant in the world grain and provision markets. The magic is his. He merely stretches phantom fingers in the air and pulls it down. KING SR. VARIOMETER ISO to CM Meter* Ha outside eoneeftlng hardware mad — reducing capacity lessee. Railed— Solid. 8I» 4'V'x 4%"x3". Guaranteed by manufacturer direct to user. Retail price $2.50 Art yanr dealer Aremco Mfg. C»., 30 East 23rd Si., N. Y. C. BUILD YOUR OWN SET THE RADIO CONSTRUCTOR Val. I — N*. 2 Just all the Press. Price 25c Mailed Thla new edition at THB RADIO CONSTRUCTOR Must off the preee) llluatreles and fall; describee the moat popular and efficient hook-up*. Full and complete instructions for construction of Flewelling Reinartz Reflex Honeycomb And Many other Tested Olrwiu Thla Is the book yon bare been waiting for. Get It today from jour dealer, or It will be mailed you postpaid on receipt of only Sac. DEALERS! WRITE FOR QUANTITY PRICESI S. NEWMAN A CO., Publishers 74 Day St., Dept. W., New York City Radiophone on Ford Truck A Ford ton truck equipped with a radiophone was one of the novelties en- tertaining visitors at the Brooklyn, N. Y., Automobile Show. Stanley Payne of the Payne Motor Company, Brooklyn, is responsible for the idea. The installation had its trial on a trip from Brooklyn to the New York Ford headquarters, and worked without a hitch. On Fifth avenue several traffic officers detained the outfjt a moment to enjoy programs. Construction of New Type Transatlantic Receiving Sets By M, B. SLEEPER Fully Illustrated. Price 75 Cent* IN addition to the listening to ships snd broad- casting: stations on abort ware lengths there Is a peculiar fascination about listening to the high- power telegraph stations of England. France. Ger- many, Russia and Italy as well sa those located In the Pacific Ocean and the Oriental Countries. It la much easier to do this than most people Imagine. The sending la rery alow, a feature ol assistance to the beginner In telegraphy. Several types of receiv- ing acta for this taak are described. Detectors, am- plifiers, oactllatore. etc.. for long distance reception are also described. Suggestions for the operation of relays by the signals and the reproduction of thorn on a phonograph are given. In addition there la some valuable data on home made waremeters for testing and experimenting. Sent P. P.. prepaid, en receipt si price, by THE COLUMBIA PRINT 14(3 RROAOWAV. MEW YORK CITY Subscribe for RADIO WORLD. $6.00 year, $3.00 six months, $1.50 three month Radio Perfection BESTONE . Spring Grip Telephone Plug The Bestone Plug Is sn entirely radical departure In design and construction, giv- ing superior results. A simple pressure of the buttons Instant- ly connects or disconnects the receivers. It Is not necessary to disassemble the Bestone Spring Grip Plug for any reason. Juat lnaert the cord tips — no more work, worry, or possibility of a poor connection. Eliminates the use of several plugs— en - sblea you to use from one to throe seta of telephone receivers, or to change from head phones to loud speaker. a>| «e without disconnecting. List ... ♦ is attained only by the use of mechanically and scientifically perfect parts. Now, more than ever, when the mar- ket is flooded with inferior goods, one cannot be too careful in the selection of standard, trade-marked articles, and in purchasing from a reliable source. It is our aim to supply the highest standard radio specialties, thus insur- ing perfect results and satisfaction. Every article we sell is unconditionally guaranteed both by the manufacturer and this organization. FREDERICK H. PRUDEN Incorporated 993 Bergen Avenue d'ersey City, N. J. __ _ _======= —

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I 26 RADIO WORLD TUNE-IN ON THE NATIONAL WAVE LENGTH AND SAVE MONEY ON YOUR PURCHASES Lowest Prices on Standard Radio Goods in the W. 8. A. POP P A HYDROMETER (Battery Tester) vrith POPP r J\IL£d each purchase of $1.00 or over JT IVCj£j HAVE YOU ENTERED OUR ADVERTISING PRIZE CONTEST? FIRST PRIZE— $250.00 Radio Set Free— Six Tube Radio-Audio Frequency Set SECOND PRIZE— $150.00 Radio Set Free — Four Tube Set, Detector and 3 stages Amplification THIRD PRIZE— $100.00 Radio Set Free— Three Tube Set, Detector and 2 stages Amplification To advertise our business we will five the above prises to the three persons sending us a list of five or more names of Radio fans and who compose the best slogan or phrase of words we can use for our advertising matter. We are interested in sending our catalogue and price lists to Radio fans. If yon are interested in Radio and in its future possibilities don't overlook this opportunity to get acquainted with us, secure low prices on your purchases and an opportunity to win one of the above prizes free of charge. In the event of two or more persons submitting the slogan judged the best, second best, or third best, each will receive the full amount of the prize tied for. All entries must be received by us not later than March SI, 1923. Our Peanut Tube Does the Work of WD-11 For Detector and Amplifying uses. Can be used on 1% volt dry cells or regular 6 volt A Batteries. Fits standard V.T. socket. Uses about 1/10 ampere, on two 1% volt dry batteries. Price of tube, $2.50, includes adapter. lVa VOLT TUBE (not WD-11, but for same use). For detector and amplifying uses. Used on 2 Dry Cell batteries (1% Tolt) $5.00 THIS WEEK'S SPECIALS 1,000 HEADSETS, $6.00 Value $2.99 each Biggest Radio Bargain Evar Offered— Ordar Promptly 200 RADIOLEAN CRYSTAL SETS, $12.50 Value $6.50 each Include* Receiving Set and AH Antenna Equipment VACUUM TUBES VERNIER CONDENSERS U. 3. Navy (PUotron) used a* a detector, amplifier and transmitting tube, all fat 11 Plate Uat fiat, one, type V. T. 14. List B.M, now MS » «»te " SJt, - 4.M U. V. 2M Detector 4JS 43 Plate " «-Se, " MS 8: S ISa^S^::::::::::::::::::::::::::::::::::::::: S °* - *-7* paid. We guarantee them to bum equal to new tubes. WD-U " S.W. " S.7S BUSS BAR WIRE — 6 two-foot lengths $0.25 DX TRANSFORMERS, $9.00 Value, Special 6.50 HEADSETS 2200 Ohm, equals best $(.00 phones on market, now S4J0 Dictograph t&ja Brandes— 2*00 Ohm 5.50 Federal US LjnW TtTl HDnrD AH goods forwarded by Parcel Post. Send Money Order with order, and I1U VV IU VSIxJL/aCsIV include the following rates with same for postage: On Purchases $1jM to S5.00, 6 CenU Postage On Purchases $10jN to S20.M, 2* Cents Postage On Purchases $5.00 to HMO, IS CenU Postage On Purchases $25-00 to $50.00, 35 Cents Postal* Space being limited, we are obliged to omit other money-saving items. Write for quotations or ask for oar latest Price Sheet Catalog. National Radio Products Corporation Mail O Dept., 509 FIFTH AVENUE NEW YORK Digitized by Google

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RADIO WORLD 27 OUR SPECIALS *7.7» 43 Plate Vernier Coodoasor KTS «5.M WD-U Transformer 0.7S $14* WD-U Socket «V Write for Free Catalogue. Perfection Pay Parcel Poet. Perfection Radio Corp. of America 1» W»t 23rd Street Nw York City VARIOMETERS «0 Aft Batter than moulded. IS* to Ml Wave Length. Unconditionaly Guaranteed. VARIOCOUPLERS, 14 tape, 14 «4- SO CA •Wed leads. Baheltte. Good far A. M. P. RADIO COMPANY SO CAST I5RD STRICT. NIW VOSK 01 TY Send money order, including- pottage. STANDARD MERCHANDISE AT CUT RATE PRICES LM fiE. rnalHHa Phil RkMtaito t .71 % .SI Froetletkaa Varaler BHiiitMl I.JS 1.19 Kleeeer Vernier RkMctati I.M .»• Kleeeer Vernier wltk Dial I.M I.M S Vett Otterter Tea* 4.SS i.U S Vett AaslMer Tate 4»t t.7S Frukeu Virlakki Qrld Leak I.M .7* CASH OS HONCV 0R0IRS WITH OROCS. RAPCO PAYS ALL PARCELS POST CHASSIS. RADIO PRODUCTS CO. 147 Weil 2Jrd Streat. Me» Yerk City. N. V. \s port h rrirA shop Established 1895 Complete Regenerative BULB SET $12-45 Outfit Includes \% Volt Tube— Fisch- er Variocoopler — 14 taps— 1 stops — 23 Piste Variable Condenser— I Knobs and Dials— Rheostat— Socket — Grid Leak Condenser— Dry Cell— ay, Volt Plate Battery— 8 Binding Posts— Also Drilled Panel— Easy to Assemble. With Federal Double fJ«J ■» Af% Hesd Phones * A * Mahogany Finish Cabinet A E for this Set ajd»,^«AT Wholesale and RetalL Mail orders filled same day, upon receipt of Money Order, Including Postage. 123 Nassau St, N. Y. City Great Britain's Wireless Plans Announced by Premier REPLYING to a question in the House of Commons on March 5 Premier Bonar Law said : "In view of the developments in the science of wireless telegraphy and the other circumstances which have arisen since the late government decided upon a policy of a state-operated wireless chain, it is not con- sidered necessary any longer to exclude private enterprise from participation in wireless telegraphy within the Empire. "The government has therefore decided to issue licenses for the construction of wireless stations in this country for com- munication with the dominions, colonies and foreign countries, subject to the conditions necessary to secure British control and for suitable arrangements for handling the traffic. "At the same time the government has decided that it is necessary in the interests of national security that there should be • wireless station in this country capable of communicating with the dominions, and owned and operated by private enterprise. A station of this kind will therefore be erected as early as possible, and it will be available for commercial traffic as well as for service messages." Secretary Hoover Calls Another Radio Conference SECRETARY HOOVER, of the Depart- ment of Commerce, has called a radio conference for March 20 to clear the air of the present chaos, due to conflict from broadcasting stations all over the country. The conference call reads in part : •The Department of Commerce has sent out invitations for a reassembly of the radio conference held a year ago, together with some additional members. The conference held last year was for the purpose of con- sidering legislation necessary in order to reduce the amount of interference in radio broadcasting. The legislation having failed to pass Congress, it is felt desirable to investigate what administrative measures may properly be taken temporarily to lessen the amount of interference in broadcasting. "Since the last conference the number of broadcasting stations has increased from 60 to 581, and it is estimated that somewhere between 1,500,000 and 2,500.000 receiving stations are now in use. The amount of interference has increased greatly and threatens to destroy the growth of the art." Radio Pioneer Injured in Army Plane Crash A HUGE Martin bomber airplane, belong- ing to the Army, and known as A-26, crashed in a vacant lot in East N'ew York. M. Y., on March 4. Lieut. Stanley Smith was killed and Major Kollctte Bradley, the pilot, was seriously injured but probably will recover. Major Bradley is cre«lited with having sent the first radio message from an airplane in November, 1912. Freshman Products, Especially Adaptable K New Flewelling "Super" Circuit VARIABLE RESISTANCE LEAK with .00025 mfd. Micon Condenser combined $1.00 without Condenser 75c. rT MICON TESTED MICA CONDENSERS .001 40c .006 $1.00 CHAS. FRESHMAN Cl«ra — stktreiM t—4 t*r. faa_ In Van »'"* "« >"» »»' •» seeeltej an*, new ieta Wn»„t rgrtixr tevi«. National Radio Service Co" 140 West 32nd Street New York, N. Y. GENERAL RADIO CO. APPARATUS W. D. 11 Amplifying Unit. $7.50 U. y. 201 Amplifying Unit . &00 .001 Variable Condenser. 5.00 .001 Vernier Condenser. 5.50 .0005 Variable Condenser. 3.25 .0005 Vernier Condenser. 3.75 HARD RUBBER PANELS Grade A 7x10...$ .90 7x 18... $1.45 7 x21... 1.70 7x24... 1.90 10 x 12... $1.40 XXX BAKELITE PANELS 7 x 10. . .$1.35 7 x 14. . .$1.85 7 x 18... 220 7 x 24... Z85 AO Part* for Lata**. Grcnita Like FleweUng and Reflex We Pay the Postage CAST OF MISSISSIPPI. IMMEDIATE DELIVERY FLEWELLING CIRCUIT ACCESSORIES a Plate Predates Condoaoon SLM U Plate Prodoloa Coadoaaeri M .SM FUed Ceaaeaaera JS Two-Cad Mount* Deforest Ueeaae US D. L. » Honey cea a Cofl LM D. L. It Hoaejrceaeb Ceil LSI Variable Grid Leah ealr JS Variable Grid Leek aad Ceod. M High Grade BakeBte Rheostat JS W.D, 11 Tube Socket JS) V. T. Tube Sachet ja Hard Rubber PaaaL rale LSI No C O. D. Postage Paid Write for pricri on other parte MAIL ORDER DIVISION ECONOMY RADIO CO. m Nassau Street New York City, N. V. Dept. R.W. YOU DX HAMS! Bar* too mm (ha tar* op wtta (aaplm fw* layout in full fiat acj «U eoruM mrt lanal (JateUta aft liMO WORLD So 11. ttaL*j Jao Iff T> s buna up aetualiT go*** ff-jt «Ad iglgsj fea |n. gjxj lar« tl at rout labia All tfuu u nerraatry u ta lay tha fuD -aajn W*mm at th« i « -,ri on ynsjr own [«4 gg4 tlriU aa-i n>rk r-wr rnJ-g Wlrai>le. len't ItT ir r -j u<^i t iM» rot-, a*ed 1 i eartta fa fttiTt IM ll"-»twir, Nr-w Tart. N T. a**! . « art i* »*. «*i rou Or gUrt yaw MbaatipUaa with that rur.brf Digitized by Google

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28 RADIO WORLD DO YOU WANT TO BUY, SELL OR EXCHANGE RADIO OR OTHER GOODS? DEPARTMENT AT k A WORD TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS This department is intended for everybody who want* quick action on short announcements covering the buying. selHns: exchanging or general merchandising in the radio field. Readers of RADIO WORLD will find that it pays to read these columns every week. Advertisers will get a ten-day service here— that is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy reaches as. The rate for this RADIO WORLD QUICK-ACTION CLASSIFIED AD. DEPT. is 5c per word (minimum of 10 words, including address), 10% discount for 4 consecutive insertions, 15% for 13 consecutive insertions (3 months). Changes will be mad* £ standing classified ads. if copy is received at this office ten days before publication. RADIO WORLD CO- 1493 Broadway N. Y. C (Phone, Bryant 4796). J. MULBERG, DEALER— Radio Sets and Sap- plies. Key West, Florida. SUPER-SIMPLICITY CIRCUIT— 1.000 to LSOO miles on oae tube, one control, 150 to 25,000 meters. No rheostat, storage battery, vario coupler, variometer, 3-coil mounting, variable inductance, taps or radio frequency. Nothing to guess about. Complete hook-up and particulars, $1.00. No checks. Build your own. Save 50% >nd get better results. RADIO EXPERIMENTAL LABORATORY, Box 194A, Berkeley, Calif. GUARANTEED VARIOCOUPLERS, S2JS.— RADIO ASSEMBLY, 1109 Valley St., Joplin, Mo. VACUUM TUBE RESULTS WITH A CRYS- TAL SET!— Cover distance with a "PT" ULTRA- SENSITIVE CONTACT in your crystal detector. Beats gold and other ordinary catwhiskers. DOES NOT JAR OUT. Using the "PT," Myrle Wood heard over 43 broadcasting stations in a thousand mile radius! Other users testify: "Heard new stations on first adjustment. Has all advantages you claim. Receives music so loud it hurts my ears." The "PT" has received 3,300 miles through static. Price only twenty-five cents. "PT" CRYSTAL CONTACT COMPANY, Box 1641, Boston, Mass. SOLDER YOUR RADIO CONNECTIONS with Radsol, the new soldering paste. Price, 20 cents. Dealers write. DAVIS PROCESS CO., 219 Devoe St., Brooklyn, N. Y. BUILDERS AND EXPERIMENTERS. Do you know that the Reflex circuit is one of the most interesting circuits to construct? You can not guess how much fun you are missing if you fail to try out at least one of these circuits. See RADIO WORLD issues of Feb. 24 and March 3. They contain two fine articles by W. S. Thompson, with plenty of new Reflex circuits to experiment with. Don't miss these! 15c. a copy. RADIO WORLD, 1493 Broadway, New York City. MAKING MONEY WITH YOUR SMALL CAMERA, 10c. coin. Wm. Kissel, Box 114, Adrian. Mich. FOR SALE— Paragon Regenerative receiver, R.A.10. Detector, and two-step D.A.2. Both $110.00. Crosley two tube set. $25.00. All ap- paratus new and guaranteed. Write Philip Cob- lentz, Middletown, Maryland. DYNAMO BUILDING FOR AMATEURS — Or How to Construct a Fifty Watt Dynamo. — By Arthur J. Weed. A practical treatise showing in detail the construction of a small dynamo or motor, the entire machine work of which can be done on a small foot lathe. Dimensioned working drawings are given for each piece of machine work, and each operation is clearly de- scribed. This machine, when used as a dynamo, has an output of fifty watts; when used as a mo- tor it will drive a small drill press or lathe. It can be used to drive a sewing machine on any and all ordinary work. The book is illustrated with more than sixty original engravings, show- ing the actual construction of the different parts. Price, $1.00. THE COLUMBIA PRINT, 1493 Broadway, New York City. EXCHANGE JOLLY, INTERESTING LET- TERS through our club. Stamp appreciated. Betty Lee. Inc., 4254 Broadway, New York City HOW TO REPAIR Vacuum Tubes. Complete literature, $1.00. Box 103, Station C, Toledo, Ohio. TWO one stage amplifiers, Acme, $8; Remler, King Amplifying horn, $7. Condensers. J. . Rich, Hobart, New York. E NEWS AND GOSSIP OF THE STAGE— Send 10c. for specimen copy of the NEW YORK STAR, the great illustrated theatrical weekly. $4.00 year, $2.00 six months, $1.00 three months. New York Star Co., 1493 Broadway, N. Y. WIRING A HOUSE. By Herbert Pratt. Shews a house already built; tells just how to start about wiring it; where to begin; what wire to use; how to run it according to insurance rules; in fact, just the information you need. Directions ap- ply equally to a shop. Sixth edition. COLUM- BIA PRINT. 1493 Broadway, N. Y. C Price, M eeata. FOR SALE— "Homcharger" battery charger, $14.00. Frost Fones. $4.00. Brandes Superior, $6.00. U. V. 200 Tube, $3.00. Volt-ammeter, "Pignolet" make. 0..W amperes, 0-30 volts, 0-3 volts, also Cadtmim eRading, mounted in neat case, $15.00. All c,kv!« nrc new and guaranteed perfect. ADRIAN SIIANLEY, Aberdeen, So. Dakota. VARIABLE CONDENSERS at factory prices. 3 plate, $1.05; 11 plate, $1.35; 21 plate, $1.60: 43 plate, $2.05. Send cash with order. GREEN- LEAF, 34 Merchants' Row, Boston, Mass. EXCHANGE LETTERS with friends every- where. Pleasant pastime. Information for stamp. Smith, Box 3125, M. Portland, Ore. PATENTS PROCURED AND TRADE MARKS REGISTERED— Advice and terms upon request. Robb, Robb & Hill, 1403 Hanna Bids., Cleve- land, Ohio; 942 McLachlan Bldg., Washington, D. C CASH FOR OLD GOLD, Platinum, Silver. Diamonds, Liberty Bonds, War, Thrift, Unused Postage Stamps, False Teeth. Magneto Points, Jobs, Any Valuables Mail in today. Cash seat, return mail Goods returned in ten days if you're not satisfied. OHIO SMELTING CO., 337 Hip- podrome Bldg., Cleveland, Ohio. ATTENTION. Amateurs!! Have you seen the RADIO WORLD'S page of hook-ape in the Oct. 21 issue? 15c a copy or start your snbscriattian with that Number. Many people are writing in for the hook-ups listed her*. RADIO WORLD. 14H BrWwar, New York CHr HOW TO BECOME A SUCCESSFUL ELEC- TRICIAN—By Prof. T. O" Conor Sloane. An in- teresting book from cover to cover. Telling in simplest language the surest and easiest way to Become a successful electrician. The studies to be followed, methods of work, field of operation and. the requirements of the successful electrician *re pointed out and fully explained. 202 pages. Illustrated. Nineteenth revised edition. Cloth. Price, $1.50. The Columbia Print, 1493 Broadway, New York City. IF YOU ARE A REGULAR RADIO fan and like to hear the stations in the four corners of the United States come in with a bang, then you will want the FleweHing Circuit. If you do, send 15c for RADIO WORLD, issue of Feb. 27, which contains complete description and directions for the manipulation of the cir- cuit. RADIO WORLD, 1493 Broadway, New York. A COURSE IN MECHANICAL DRAWING— By Louis Rouillion. The author has written a most practical book on the subject of Mechanical Drafting. It fully explains the art of Drawing, Lettering and Dimensioning. It is, by far, the most practical book ever published on this (ab- ject, tor use in day and evening schools, sad more especially adapted for the teacher and for •elf instruction. Fifteenth edition, revised and enlarged. Fully illustrated. Oblong. COLUMBIA PRINT, 1493 Broadway, N. Y. C Price, SUS. STANDARD ELECTRICAL DICTIONARY— By Prof. T. O- Conor Sloane. Just issued an en- tirely new edition brought up to date and greatly enlarged— aa a reference book this work is beyond comparison, as it contains over 700 pages, nearly 500 illustrations, and definitions of about 6,000 diatinct words, terms and phrases. The defini- tions are terse and concise and include every term used in electrical science. 767 pages, 477 illustrations. (See page 18 for fuller description.) Price, $5.00. The Columbia Print, 1493 Broadway, New York City. MODEL MAKING— By Raymond Francis Yates. A new book for the mechanic and model maker. This is the first book of its kind to be published in this country, and all those interested in model engineering should have a copy. The first eight chapters are devoted to such subjects aa Silver Soldering, Heat Treatment of Steel Lathe Work, Pattern Making, Grinding, etc. The remaining twenty-four chapters describe the construction of various models such aa rapid fire naval guns, ■peed boats, model steam engines, turbines, ate. 400 pages. 301 illustration a. Price, $3.00. The Columbia Print, 1493 Broadway, New York Gty. RADIO- APPLAUSE Post Cards. Encourage broadcasting by such acknowledgment. 2 dozen 25c, postpaid, D. J. SPANGLER, Elkhart, Ind. VERNIER VARIABLE CONDENSERS— Ca- pacity, .0006. $1.48 postpaid. Fully guaranteed. Cherpeck Company, 3123 Davlin Court, Chicago. BATTERIES — Edison Storage "B" Batten Elements, 5c per pair; 18 will make one OS volt Battery. OILMAN'S BATTERY SHOP, Chelsea Sq., Chelsea, Mass. RADIOPHONO Adapter— Your Edison, Bruns- wick Victrola or other talking machine has the finest acoustic properties possible. Radiophono Adapter enables you to use it as a loud apeaker. Patent (Pend.) Molded Construction. Sent on money back guarantee. At your dealers or direct from us. $2.00 post prepaid. Industrial Sales Engineering Co., 671 Broad St., Newark, N. J. OLD MONEY WANTED — $2.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coin Company, Ave. 83, Le Roy, N. Y. AGENTS— Are you interested in radio? If so drop us a card. We have a proposition no live agent should turn down. Meets the needs 2L90 EST eent- of ,he Public. THE WILKENDA CO^ 500 Fifth Avenue, New York City. Dept AMATEURS— LOOK I Send in 15 cents to RADIO WORLD for issue of January 20 con- taining panel layout, hookup and full explanatory data on the construction of a D-X receiver, which simply lays the long distance on your table. Or start your aub. with that iaasue. RADIO WORLD, 1493 Broadway. New York CSty! DO YOU WANT TO SAVE MONEY in making your set? Send for the Jan. 27 issue of RADIO WORLD, containing a full-page draw- ing of how to make filament control rheostats, as well as an easily understandable text, which makes the construction eaay. 15c a copy, or your subscription with this issue. RADIO WORLD, 1493 Broadway, New York. K^^McNALLY RADIO MAP OF UNITED STATES-Is.28 x 30 inches in size. The locations of broadcasting stations are shown by distinc- tive symbols. The call letters of each station "e.Siven. also the wave lengths of each. The Radio Districts with numbers are shown in red and the Radio Relay Divisions are in blue. Time zones are included. Alphabetical lists of stations and alphabetical lists of call letters are in the margins. Convenient pocket form with cover. Price, 35c. The Columbia Print, 1493 Broadway, New York City. TWENTIETH CENTURY BOOK OF RECIPES FORMULAS AND PROCESSES-Edited IrrGajr? ner D. Hiscox. This book of 800 pages ia the moat complete book of recipes, ever published, giving -r— !-•«■••. — , ■<=vf<=» ever puonsnca, givin| thousands of recipes for the manufacture of valu- able articles for every day use. Hints, helps, practical ideas and secret processes are revealed within its pages. It covers every branch of the useful arts and tells thousands of ways of making money and is just the book everyone should have at his command. The pages are filled with mat- ters of intense interest and immeasurable prac- tical value to the photographer, the perfumer, the painter, the manufacturer of glues, pastes, cements and mucilages, the physician, the drug- gist, the electrician, the dentist, the engineer, the foundry man, the machinist, the potter, the tanner, the confectioner, the chiropodist, the man- ufacturer of chemical novelties and toilet prep- arations, the dyer, the elect roplater, the the engraver the glass worker, the gold-beater, the watchmaker, the jeweler, the ink manufac- turer, the optician, the farmer, the dairyman, the paper maker, the metal worker, the soap maker and the technologist in general. A book to which you may turn with confidence that you will find what tou are looking for. A mine of information •ip-to-date in every respect. Contains an ira mense number of formulas that everyone ought to have that are not found m any other work New edition. 807 octavo pages. Cloth binding Price. $4.00. The Columbia Print, 1493 Broadway. Vew York City. Digitized by Google

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RADIO WORLD 29 RADIO PANELS lt"«M" Hit* Naaataatarara- aaaalal ataaa mtMf*. LW PAGESON COMPANY •a It. iMtnH IUUh. St LMlfc m*. LETTER TO THE EDITOR All Wan Oauplar. alta trM dlaaraai 14.10 HIM) Caak (Ml — D L M.. 50 I .SO Homy OMb Oil — D t No. 75 MO O-Way PIMM Caaaaatar .71 45 Vtlt B Battariaa 1 .71 It ft V«M B Battariaa -I* Acs* Traaafarawra J-J2 Saaatal W.O.-II Tluihfmw J-tO Klaa Varlaaaatar »•*» Satail Tyta Varlaaaatar 1.7} Caaalar '•" WHITE RADIO CO. in E. ZSrd ST. NEW YORK CITY Cash with OHar-WaotaaaR Ratal! Original Nathaniel Baldwin $11.75 FREK with aaoh Ir of 15 00 m Phonaa eaa Da oaad aa baad aat ar aa »«!« Combination make* a wonderful load apeakar. Cath with order or C. 0. D. WALTER SCOTT 10 Ot. Lakaa Plata MaaWaJr. H. J. TUBES REPAIRED WD-11 $3.50 AND POSTAGE and other Vacuum Tubes, 8uchasU.V.200,U.V.201. U. V. 201A Repaired and Guaranteed. (NoV.T.lorV.T.2) Mail Orders Solicited and Promptly Attended To. H. & H. RADIO CO. 514 Clinton Are. Newark, N. J. LATEST AND BEST RADIO BOOKS 0'ir Standard «n.| tTp-tA-v M II . .75 Centtructicn of RatNophont and THearaph Rec^iv*"* for Reqinner* H M II S . -«:■«•• .7S Htv to Make Caamartlal Typo Radio Ap. para. in i > M It sv.i tr . . 75 The Radio Experimenter'* Hand Book by M ll SI'-' ;t ■ I. OS A B C of Vacuum Tube* U»mI la Radio Re- ception in- y. ii i-wi* i.oo Wireleu Telegraphy and Tclrphoay Simply Explained >.\ A IV M -t.fi. . 1.50 EiOTimrntal Wireless Stations t.y I* E >4ll III,*!. Sent Parcel Pott, prepaid, oa receipt of price k> THE COLUMBIA PRINT NEW YORK CITV 1413 BROADWAY Radio World's Assistance Demonstrated EDITOR, Radio World: Many of your readers may be dismayed by the choice of so many different hooks-ups and the extravagant claims of their partisans.^ To these I want to call attention to the simple and efficient WD-11 set described in your issue of January 20, 1923. by Ortherus Gordon. I studied this article carefully, bought the various herns required, and, after one day's work, with a total expense of $18.63, exclusive of phones and aerial, -was bring- ing in stations over a thousand miles away. These include, in the East, Schenectady, Troy, Newark, and Charlotte, N. C. ; in the South, Atlanta, Birmingham, New Orleans, Dallas and Fort Worth; in the West, Denver, Salt Lake City, Great Falls. Mont., and in the North, Minneapolis, Milwaukee and Chicago. Since adding one step of audio amplifica- tion I have received very plainly over fifty distant stations. The significance of this is apparent when you consider that the almost constant operation of the two powerful local stations prevents listening in when the majority of concerts are being broadcast. To Mr. Gordon's explicit instructions let me add the importance of a proper aerial. The labor of winding the two coils can be saved by buying them already prepared at a very slight expense. The simplicity of tuning this set and its selectivity are two important virtues. March 1. 1923. E. Stanley Field, Jr. 821 E. 42d St., Kansas City, Mo. New Technical Director for WGY HARRY S ADEN WATER, one of the heroes of the air service of the Cnited States Navy, has been placed in charge of the technical operation of the broadcasting stations of the General Electric Company, including WGV at Schenectady. N. Y.. and the projected station at San Francisco, Cal. Two years before he entered the ranks of the Radio Engineering Department of the General Electric Company Mr. Sadenwater was a lieutenant in the United States Navy, and was one of tlie few out of hundreds of volunteer! selected for the hazardous flight of the NC flying boats. NC-1. NC-2 and NC-4. across the Atlantic, from New- foundland to 1'ortugal. l.iet'temnt Sadcnwater was radio officer in the NC-1. commanded hy Lieutenant - Comm.inder P. N. L. Bellinger. The NC-4. it v. ill Ik- recalled, w as the only one of the three (vats successfully to make the cross- itur. The NC-1. which carried Licuten irt Sadcnwater. encountered heavy fog Naviga- tion was made so difficult that the his f!>ing boat wis brought down to tl'at on the *ea until the fog lifted. Instead ot the calm sea expected the boat ran into rough water, and in a very short time the NV-1 was so badly rammed hy the waves that it was in-possible to ride off the water, and every minute added to the damage. Lieutenant Sadenwater sent out S' >S calls until the batteries became exhausted. A Greek freighter finally sighted the NC-1. and picked up her crew, which was landed safely at Il'»rta I- aval in tie A.'"rc« Lieutenant Sadenwater. with other •ner-!— it;- n wdl ltc held at ?..n Francivo fr-.ui \t>'il 3 to R inclusive A home-made set cutest for amateurs will be a feature f the show RADIO TUBES REPAIRED "taaraataat Coaal «a Hem" FBUM DAY BfHVICC 0 V. Dataatara. It. St; AaaJttara. It.tl: I Watt Pawar Tataa. 14.00 MaWM Takaa Ahraya la ttaat Our repaired tub*! epeok for thamerlvre Radio Tab* Labor* to rim. Inc. 770 B*aa4 ttraal Hmrk. N. J.. U. I. A. BOBBINS RADIO DESK The Place for Your Radio Set and Equipment Closed compartment! (or Batteriea, Head Seta. Tooia. Extra Parta and other Appli- aocca. Uaeful and oraamcattl ia aay with a receiving act. la oak tad aaafeoi any finiah. Send for lltutt rated Literature. ROBBIN8 WOODWORKING CO. UBEarwnxE, ojjnois KULTIPOIMT A Sratfcatlt CRYSTAL. DETECTOR Ita 50c 2S ir daalar ar Mnn tr«m aa Cara.. tl Part " . N. Y. RUSONITE CATWHUKEa U- Karat SaM Maltlaa aaatart. £5C STUYVESANT Radio Corporation IS E. IITH HTREET. NEW VOKK CITV Bat. Itk An aat Ualaa taaara HEAD SETS $l?oT Ra'.lMln Orlplnol I».,jl rm %9 00 f. no |Ul 'tin O' .- • \i mug.f 4 75 . ,, v,M ,: ^ J 75 » C»'- »- :_'i"> Ohrrii 1.2% • II- :.. rut, 5 -"5 j ucr» ... ISO A.f.l H II . : !• .- !• ... I 0 0 \i > J: '0 \. Tr»' v..r—-n 4 10 \l Id »■•-. . . «0 •s.k,-. I i -t. *0 •». ••■ ll-'l I'-.'U 70 I .t:l. T-a •» 1 ■ " f.i.t, w i> ii »» Full Ll»» of All Standard Sets and Accessories at greatly Raducaxi Price*. Wrilt for Our Quotations \\r Milp All Vail Onlrra Namr l>»7 aa Hr«-rl> ral. frntl Monr; Or.lrr Ifarlarilac Poatmco STUYVESANT Radio Corporation IS K. UTII STKI KT. N KW V«KK t 11 V B.I Jtk Aia. aa< Vn» Saaara Digitized by Google

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30 RADIO WORLD 120M-OHM RESISTANCES IN STOCK Far tks New Saaar Wrseltt RADIO STORES CORPORATION DISTRIBUTORS lit W. (4t» St.. N. V. City LMHW ISIf 'Sll* RADIO PANELS l\s.^«e Musr. lash. Hsds sf uts^sfesst .irsst. Mack nbrs. This ssstsrlel nwm l»Ua dlslsstrls ltxU. II-**- MW WILEY PANEL CO. MM as. Oeatral Park A«k. Okleee*. lit Rexite Synthetic Crystal* Sensitive over the entire surface. Price, including special catwhiaker, Ms Dealer i — Write for unusual proportion. THE AIREX COMPANY Z37 Centra Street New York CRYSTAL FANS Are you satisfied with your crystal, or do you want better results? MOLYBDIC GALENA A new detector just discovered is sensitive even when ground to dust Send 50c for one of these wonder crystals. We will refund your money if you are not entirely sat- isfied. Phoenix Radio Laboratory Box 168, Phoenix, Arizona The Niftiest Short Wave Tuner on the Market Only S4.M A PP on 1 lb. Send lor pamphlet. L. W. GOODMAN DREXEL HILL, PA. Tin GOODMAN Is really a nigh frads laetrumeet. well and sturdily Mastriietsd. Ths PANEL and FANS art GENUINE BAKELITE— ths best material known for ths purpose. "The Little Wonder" FOR BOYS AND GIRLS CRYSTAL SETS Unat—mbled-Nut Catches distinctly everything broad- casted within 30 miles. We also manufacture the "Little Wonder" assembled set at $5.00. GUARANTEED TESTED CRYSTALS Galena 15c Radiosite 20c Write for Free Catalog. It lasts all ear redte «* eappUsa Hollo way F' Co, Inc. 2S8 Third A- irk City RADIO WORLD TELEPHONE. BRYANT 47 B« PUBLISHED STY KB Y WEDNESDAY (Dslsd SATURDAY OF SAME WEEK) FBOM PUBLICATION OPTICS. 1498 BROADWAY. NEW YORK. H. Y. BY HENNE88Y RADIO PUBIJQATIOWS CORPORATION ROLAND BURKE H EN NEBS Y. ITesldent and Editor M. B. HENNESPY. Vice-President FRED 8. CLARK, Secretary and Manager 1493 BROADWAY. NEW YORK. N. Y. Man&a-ins; Editor Stephen L. Coles Technical Editor Robert L. Doughsrtv SUBSCRIPTION RATES Fifteen cents a copy. 10.00 a year. SS.tl tar six months. 11-50 roc tons months. Add $1.00 a year extra for foreign postage. Canada AO cents. Receipt by new subssrlbera of the first sopy sf RADIO WORLD mailed to tbass after ssodlng la their order. Is automatic acknowledgment of their subscription order. ADVERTISING RATES One page: One time— 1150.00. Half Quarter. Third and Two- thirds pases st proportionate rates. One Inch, ess time— 10.00. Par acsts Una 10.40. On four ransecutiro Issues. 10% discount. On thirteen consecutive Issues. 15% discount. Cover and preferred-position rates suds known on application^ Terms: SO dsys net. 1% 10 days. CLASSIFIED ADVERTISEMENTS Five cents per word. Minimum. 10 words. Discount of 10% on 4 consecutive issues — 15% on thirteen consecutive Issues. Caen with order. Entered ss second-elaae matter, starch 28, 1922. at the Post Office st New York. New York, under the set of starch ». 18T9. IMPORTANT NOTICE While every possible sere Is taken to flats correctly matters of fact and opinion In technical and general writings covering the radio field, and every line printed Is gone over with s scrupulous regard for the facta, the publisher disclaims say responsibility for ststements nsgsrdlng Questions of pstents, priority of clause, the proper working out of technical problems, or other metters that msy bs printed lo good faith and on Information furnished by those supposed to be trustworthy. This statement Is ssads In good fslth and to ssvs time and controversy lo matters ever which the publisher ssnnot possibly nave control. Is "Amateur" a Misnomer? A VERY literal Englishman recently re- marked to a man who was very much interested in radio, and had been for the past eight or ten years : "I really do not see why they call them 'amateurs.' From what I have noticed and heard, they seem to be as well equipped if not better than most of the operators on board the ships. Not only that, but I have had the opportunity to see them actually handle messages, and the re- markable precision and accuracy with which it was done actually astounded me." This is a very true conception of the American amateur. In nearly nine cases out of ten the average amateur, that is, the one who has owned a transmitter for the past five years or more, is more of a professional than the professional himself. In most cases amateurs have not the amount of money necessary to buy the expensive apparatus. So they are their own manufacturers and they turn out apparatus that works as well, sometimes better, than the commercial apparatus. This fact was recently brought out in the transatlantic tests. The distances covered on short waves with low power go to show that the amateurs have by means of a purely non-commercial association, that is merely for the benefit of the American amateur at large, developed into a force that is in many cases causing the various com- mercial enterprises to look to their laurels. White's "Varioment" Cement Make your own coils. Construct variometers, varls- couplers, etc. No distributed capacity. Holds wind, ings securely and permanently. FOR BANK WOUND COILS — "For this operation of cementing the three tuma together shellac will not do." — Radio World, March 10. Send 2."o. for sample bottle WHITE RADIO COMPANY 123 East 23rd Street New York City txselleet 41 Plata 0 .SSI IMS Exsslleat .0001 Variable Ossdoasar I. It Varleaeten. Balewie Stale. Wees] I J« KhMJ Amalrtsae Lead Yalkara iM Fesr-Ceo-Ustsa aUHUhssea US CASH WITH ORDER Radio Engineering Co. 2 Weet ath Street New York dtp NU-TYPE ANTENNA !•% mere avians, 55% Leas Vsrtats a* tbussst el tube*, walsh mesas lower burst set takes CAN BE BUILT FOR S2.59 Complete inttructiom and diagram, f LOO E. A. Spugnardi, Brazil, Indiana. Novo NOTE THE INSULATED BINDI> POSTS AND 7lM. WIRE CONNECTOR. NOVO lVI'F'G CO. GUARANTEED REPAIRS Broken and Bumed-Ont VACUUM TUBES W.D.-11 nof accepted for repair Veur dealer should ksse. kst If be ekes est. ssad direct ts HARVARD RADIO LABORATORIES Boston t, Mass. t) ~ Tabes rsturaae) Parssl psst C 0. 0. • Ml Detectors ^niplifiers To the Man with an Idea I offer a compreheneive, expert- enced, efficient aervice for all prompt, leg-aJ protectioe^i sn£ ths development of his propositr Send sketch or model and descrip- tion, for advice as to coat, through prior United States . etc. Preliminary advice fUo'T furnished without ulsei S«- My experience and lamfltarity with various arte frequently enable at to accurately ad viae clients ss_ to probable patentability fo to any expense It MS let tt valuable far properly request w RICHARD B.OWEN.fataat I 12 Owsa Bundles. Wesklastea. D. 0. 2270- P Wi Address Wanted:— The address of Arthur Kimberling. Write Business Dept., Radio World, 1493 Broadway, N« York City. Digitized by Google

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RADIO WORLD "My 'Sunshine' Friend" "'TpO soothe you, like the silences of open places; like the satisfaction of complete repose; like the strains of dreamy music— I recommend my 'sun- shine' friend — Ridgways Tea." AWARDED THE HIGHEST HONORS OBTAINABLE Gold Mvdal San Francs too 1915 Grand Prix* San Diego 1916 l^dffbjqys Tea Orange Pekoe Tea Sold in 1 lb., % lb.( M lb. and 15c Tins A GENEROUS SAMPLE WILL BE SENT ON REQUEST Addrrtf Ridftrmyt Tea Co.. Drpt B. 60 Warren Street. New York. The Finest Tea the World Produces Digitized by Google

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RADIO WORLD Filkostat Proven Best Filament Control lllllllllllllllllllllllllllllllllll 1 1 III 1 III 1IIUI1 1 1 1 1 !, 1 II 1 1 II 1 1 II 1 1 Comparison 3 of Fine w Adjustment Control Run ye 3 Ql I UKUIUl With Rheostats e and Other Filament Controls Clearly .0 Indicates M Filkostat Superiority, as it i Permits Perfect and Gradual • Current Increase .5 With Infinite Adjustments. .4 Tests made A J Standards Instruments J iiiiiiiiiiiiiiiiiiiiiiiiHiiiiiiiin IN* the Filkostat, a new filament control just perfected by S. R. Hippie, well known as an inventor of apparatus for the control of electric currents, there is at last presented an instrument which is distinctly designed to utilize the great tuning possi- bilities of the vacuum tulie itself. Radio set builders, amateurs and manufacturers have been looking forward to the advent of just such a device. They have realized that all rheostats and other so-called fila- ment regulators, are merely adaptations of pre-radio day devices, not capable of ad- justing the infinitesimal graduations of fila- ment HEAT which adjustments are essen- tial to perfect tuning. PERFECT TUBE CONTROL The Filkostat permits perfect regulation of fi lament heat. Since the heat emitted var- ies as the square of the current, fine cur- rent regulation becomes extremely neces- sary to accomplish. This governs the flow of electrons. Proper control of the elec- tronic flow in the tube permits the very finest tuning conceivable. The fine adjust- ment of the Filkostat starts slightly before the tube begins to function. With other filament controls, what minute adjustment there is, starts when the filament is almost a* maximum heat. Between 1800 degrees — dull red glow — and 2(150 degrees — white heat — the Filkostat control is so fine that increases of temperature of fractions n] ■ dnirce, with corresponding variations of electronic flow from the filament to the plate, are obtainable. I ONGF.R TUBE LIFE; NO NOISI S The initial inrush of current prevent- tin • crystalization of tbe filament which so experts claim . • • ur- when the current fed too e life Further- more the extreme degree of finenos in in- crease and decrease of electronic flow by infinitesimal variations, makes the Filkostat control ideal. The perfection of design including ample internal contact is the cause of this new in- strument being non-michrophonic, absolutely silent, and free from all noises. (DEAL FOR WDM'S AND DX WORK The lower curve on tbe graph above is eloquent testimony as to the Filkostat's adaptability to any dry cell tube. These tubes using only a fraction of an ampere demand an instrument that is so finely ad- justed that this fractional current can be perfectly regulated. This the Filkostat ac- complishes. OTHER FILKOSTAT FEATURES The Filkostat has a definite off. It is so designed that tbe filament extinguishes abruptly indicating that tbe A battery sup- ply is completely disconnected. At Full On the Filkostat resistance is practically zero Tbe Filkostat consists of a hollow cylin- der containing the special resistance mater- ial place* between two large adjustable contacts C ttltrolled by turning the knob. The Filkostat is to all purposes "fool proof " It is compart in form, takes very liMle space on the panel and *o motlntable that it can replace any other control without rrdrilline. THE RESISTANCE ELEMENT is so finely divided tb.it no further division is possible. There ar,- ii" di-ks to break or chip The RESISTANCE remains CONST \N'T at any |msition elimin.iline current varia- tions once -e-t. Such variations ire no) .ip- pareiil to tin person limine. c\ -eptitig in "fadilii: out" nf mati. ■))- and noises Uul in the lab. .rat. iry, vhen I I ; || | - n I .• ui.nl :, . ' ■ ■ ' mm court*' mcjrtfjf rtamrtm ttuuk LIKE THE RISING SUN 12 & 4 Reasons Why you should say 'Filkostat' for filament control — 1 — Not adopted to vacuum tabes ad- justment, distinctly de-signed fnr it. 2— A REAL Filament control, NOT just a rheostat. 3 — Permits infinite adjustments of fila- ment HEAT. 4— Infinitesimal control electronic flow. 5 -Permits fine tuning needed for DX. 6— Control of small current makes ft ideal for WDlTt. 7— Fine adjustment starts where tube BEGINS to function. s- DEFINITE OFF — indicating A bat- tery disconnection. 9— At FULL ON Resistance is prac- tically zero. 10 — No current variations — resistance always constant. 1 I - Resistance element so finely divided further division impossible. 12 — No disks to break or chip. 1 : Opmi, P,n. 218-222 West 34th Street, Ne« Vott II irr or ders filled to Jobbers and Dtiirn $2 $2 Digitized by Google

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lie. a topy March 24 *bW » * » MA 52 Numbers TT Q T D A T U T\ wm RADIO RECEIVING SET MAKES WRITTEN RECORDS ■ \i ? I. ! (C Harris ami kwuig) An ingenious radio receiving set, the novelty of which is that it makes its own record of messages received, without the necessity of operator being- constantly "on the job." It recently was per- fected for use by the Bureau of Standards, Washington, D. C. The illustration shows the two inventors, Dr. J. C. Karcher (left) and Dr. E. A. Eckhardt (right), getting their machine Into final working order. The large cylinder in the center of the picture is the roller upon which is drawn a jagged line, representing- the dots and dashes of the message, and which preserves the record of the signals received. The record is taken down by an ordinary fountain pen which travels horizontally across the sheet, actuated by a very slow feed fine machine screw attachment, driven by a small motor. The signals themselves are amplified, and the output actuates a very sensitive relay which in turn works the mechan- ism which cause* the pen to oscillate in irregular lines, which are transcribed at the leisure of the operator.

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RADIO WORLD WILLARD WILLARD RADIO CO. Dept. R. W., 2*1 BiaAny, New York REINARTZ CIRCUIT EVERY PART COMPLETE I Relnartz weund sell. I tube «»*»t. • rheostat I 23-elate .0006 MFD variable wn. denter?! 13-ptete .00025 JIFD varlabl.ee.. denser 3 laduetanae twltabee, 10 twite* points ud nub. 0 binding peats. I variable ■rid Ink. I -002 MFD phone MndmHr. aesastary bat b«r wire, I tnuta Radtea panel and dl.irao.JMQ Q() ud eeaplete fnstruotleas y FLEWELLING CIRCUIT EVERY PART COMPLETE 2 hmeytsab sella. I 2-eell "tajles. '."S1 ■Intl. 1 -000 hhuitv I variable frld leek, 1 arid leak. I 23-elate .0005 MFD variable MdutJr I Vernier rheostat. I tub* *M .6 blndlao petti, 20 feet b«i bar wire. I Jrln*. trads RADION eejurf, I 3" dial and *» Radle DUMt Bteklet en On- eraUM ud Ooaotraotlea or °>' §\l.Q[) TWO STAGE AUDIO FREQUENCY AMPLIFIER EVERY PART COMPLETE I 7x1 puel. 2 audio frenueney »T»»*™?" (5 to I ratio), t rbeettats, IV. T. sockets. » Juki (double olroult). 7 blndlni potto, I variable resistant, leak, neeeaeary but bar wh-e. Oan be vttd "" $11.00 HHtulry with any olroult v Write for our Catalog No. 7 Dluttrating and describing all our products. Every article advertised abovt is guaran- teed both by the manufacturer and by ney Moil ■ ' *~ Hon over »i - others include pottage, ail order* filled immediately— traruporta- m PREPAID on all orders of $5.00 or •er east of the Mississippi River. All The PERFECT RECEIVER g One Tube Reflex Eadorud by the Now York Evening Mall Brings in DX Complete. Make One Tube Do the Work of Two PARTS CONSIST OF THE FOLLOWING: One Super Sensitive Cryotal One Cryotal Detector One WD-11 VT Socket 20 Feet of Buas Wire One 7x14x3/16 Formica Panel (Drilled) Eight Marked Binding Poeta Two J-ln. Pathe Diala 14 Switch Pointa Z Switch Levera Four Stopa One Rheoetat One Double Circuit Jack One DL Honeycomb Coll No. SO One 43 Plate Condenoer 180 Degree Variocoupler One Audio Transformer Two .002 Mica Condensers Total $17.50 Spider Web Inductance Coil 31 M .0001 Variable Vernier Condenser $5.00 Above to be used with Relnartz Tuner. National Headsets $4.25 Federal Headsets $5.00 Kellogg Headsets **** Western Electric Headsets $8.50 Formica Panels, cut to measure.. 2c sq. in. A complete line of Weston Instruments in stock. Also a full line of all makes of Radio Supplies. MAIL ORDERS ARE OUR SPECIALTY American Radio Stores 235 Fulton Street, New York City All orders mutt include pottage, and all cheeks mutt be certified. igh Class Printed Stationery Carda. 600. 32.45; 1000. 33.85. Letterheads, watarnurked, 500, 32.85: 1000, $4.60. En- SopeTsend. 500, 13.25: ioos-m.™. 1^™.. cosh with order. Chariot prepaid. Work Guar- anteed. FEDERAL PRINTING CO. 1840 CALIFORNIA ST. DENVER, COLO. VARIOMETERS •" — $2.50 Batter than moulded. ISO to 000 Wave Length. Unconditionally Guaranteed. VARIOCOUPLERS, 14 taps, 14 sol- tfO RA dered leads. Balanitis). Good for

Genuine All-Ware Coupler 7.M 310.00 — 8000 Meter Coupler 4.S8 WHEN ORDERING BY MAIL Add Foetawa by the Faltewtas; otaesVp PURCHASES •Jp to *IM asial Ma. 91.01 to 9«-0» " "s. 5.01 to S.00 " ■•». 3.01 to 8.00 " 5.01 to 7.00 " 7.01 to 10.00 " **•■ Money ardor or arse at! ehook aootptad. All above quotations tubltct ta prior tale. RADIO STORES Dept. E. 3, 191 Fultoa Street, N.Y.C NEW YORK'S GREATEST RADIO MAIL, ORDER HOUSE No Free List Radio World has no free list. The only copies sent out by the publish- ers are to fill the ever-increasing orders of the American News Com- pany, the large numbers of subscrip- tion orders received at the office of publication, and one voucher copy to each advertiser and advertising agent represented in current issues. oadway, N. Y. Radio World, 1493 Brc

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VOLUME TWO OF RADIO WORLD [Entered ss second-class matter, March 28, 1923, at the Poet Office at New York, N. Y., under the Act of March 3, 1879) A Weekly Journal, Published Every Wednesday and Dated Saturday, by Hennessy Radio Publications Corporation from Publication Office, 1493. Broadway, New York, N. Y. Telephone: Bryant 4796. VoL II, No. 26. Whole No. 52 March 24, 1923 15c per copy, $6.00 a year Dr. Lee De Forest Demonstrates His Talking Picture Machine ■v ■ hat ■ Dr. Lee De Forest demonstrating his wonderful new invention which will make talking- motion pictures (C. Paul Thompson) "Photkm" tube, which is the heart of the invention. possible. Dr. De Forest is holding the A vital step forward in the field of science was demonstrated on March 12, 1923, in Dr. Lee De Forest's studio, New York City, by Dr. De Forest himself. The device exhibited was a machine for photographing the human voice on the edge of a regular motion picture film while the picture itself is being taken. Dr. De Forest has been working for the past three years on this invention, and has at last been able to call his experiments a success. The illustration here- with shows the inventor, who is also responsible for the present day audion and vacuum tube, with an or- dinary motion picture camera, which he has adapted for use with his new device. He is holding what is termed a photion tube, that is used to produce the voice on the firm itself in a manner that at the present time cannot be made public. By means of this device it will soon be possible to sit in your favorite moving picture theatre and instead of looking at the "pictures" you will also be enabled to hear the voices of the actors themselves. This idea is not new in itself, as many inventors have attempted to do the same thing for a number of years. Those of you whose memories are good will remember the attempt to synchronize motion pictures and talking machines at the old Eden Musee in New York some years ago that met with such a terrible failure. Digitized by VjQOJJLC

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4 RADIO WORLD Combining Radio Frequency and Regeneration By C. White, Consulting Engineer R\DIO frequency amplification and regeneration have often been looked upon as two different ways of obtaining the same end and have sel- dom, if ever, been considered as a possible combination. The reason for this opinion has been due largely to the trouble experienced in keeping the tubes in the radio- frequency stages from oscillating. This tendency has existed even when no type of tickler or feed-back was employed. Poorly designed radio-frequency amplify- ing transformers, inductive reaction of the fields of the various radio stages due to a compact assembly with little or no intershielding, poorly insulated connecting wires, and incorrect style or make of vacuum tube have been blamed. But, the most potent reason, which was the feed-back of current through the common "A" and "B" batteries, was generally left unconsidered. From my own laboratory experience it has been defi- nitely proved that howling and other reactions that arc far above the range of audibility are produced by this Schematic diagram illustrating the method of combkung radio frequency with regeneration as explained in the ac- companying text. The choke' coil* (x) are absolutely rv sary to the correct functioning of this circuit. frequent cause. Many receivers using a single tube as a detector without a tickler or feed-back and several stages of radio-frequency severely suffered in their range of reception efficiency due to the fact that at times for no apparent reason one or more of the tubes would start oscillating. At times, however, the inter- reaction was so severe that a constant hum or whistle could be heard' in the phones. After placing choke coils and by-pass condensers in the battery lead wire circuits it was ascertained that practically all trouble due to oscillations was eliminated, that the reception efficiency was remarkably increased and the reliability or stabil- ity of operation was greatly enhanced. So stable and steady did the operation become when a potentiometer was placed across the filament of each tube in the set that it was decided to try out a tickler coil in the plate circuit of the detecting tube and see if the old tendency to oscillate when the filament was turned up a little too high returned. It was found, however, that there was practically- no difference between the outfit and an ordinary regenera- tive receiver in case of oscillation and stopping the same to adjust for maximum regeneration which is ob- tained when the detector is on the verge of jumping into oscillation. The receiver tuned-in very distant stations as easily as a good reliable single circuit re- generative tuner picking up local stations. So clear did the distant stations come in on a loud speaker that for a time we were almost certain that it was, a rather nearby broadcasting station. To many looking for the first time at the diagram the cost of this set will appear to be excessive; but such is not the case, for it is possible by careful selec- tion of the right apparatus and the right place to buy to complete this set at a total cost of about $150. For the amateur who wishes to extend the range of his present single circuit regenerative tuner, the schematic connections as shown in the illustration herewith will be an aid. It simply will be necessary for him to insert two radio-frequency amplifying trans- formers and two extra tubes before the detecting bulb and add the audio-frequency stages after the detector. Then he will have the combined advantages of two stages of radio-frequency, a regenerative detector, and two stages of audio-frequency amplification. Of course, he will have to place in the lead wires of his outfit the necessary choke coils marked X and the by- pass condensers designated by the letter C. Although the potentiometers are an added refinement still their use is fully justified since with them in the circuit it is possible to hold the grid of each tube to the correct negative potential and thus cut down all tendency of oscillation in the radio-frequency stages, thereby con- fining oscillation and regeneration to the detector tube alone, where it should be. The constants and the types of apparatus for the various important parts of the circuit are as follows : The condenser C-l is a 23 plate air variable, the unit E-F is an ordinary standard variocoupler employing E for the stator in the circuit and F for the rotor. All the units marked P are potentiometers having a resist- ance of about 250 ohms, the units marked X are choke coils that have an inductance of .1 henry, and the con- densers lettered C have a capacity of .25 mfd. apiece. The transformers labeled R.T. are the radio-frequencj transformers and those with A.T. on them are the audio- frequency amplifying transformers. A grid leak and grid leak condenser are recommended for use in the grid circuit of the detecting tube. The resistance and capacity of the same solely depends upon the particular tube used and easily can be found by trial, since the operation of the entire outfit does not critically depend " upon it. The condenser C-2 is a fixed mica condenser of .002 mfd. capacity. The "B" battery terminal marked B-|- is the positive terminal for the plate voltage applied to the detecting bulb, since it will be necessary to impress less plate potential on the detec- tor than on the amplifiers. In order to keep the ex- pense of operation as low as possible it is recommended that the new UV201-A Radiotrons or Cunningham's C301-A tubes be employed for all the stages and the detector. WD- 11 tubes do not function satisfactorily with this type of circuit, and the ordinary tubes would require five amperes at five volts for operation whereas the type recommended would require only 1J4 amperes at five volts — just one-fourth as much power to light the filaments. Phone terminal jacks can be used on the audio-frequency stages but it is far better to adjust amplification by lowering the filaments of both tubes than to put out one tube and burn the other brightly. Digitized by Google

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RADIO WORLD Boy Scouts Carry Radio With Them on Hikes By David B. Rogers WHEN the Boy Scouts go week-ending at Kanohwahke Lakes, N. J.> m the Palisades Interstate Park where the Boy Scout Founda- tion of Greater New York conducts the largest all-the- year-round Scout camp in the world, they carry their radio with them. During the day it is useful for keep- ing in touch with headquarters, and at night it is called upon to prove its recreational value. Several hundred Boy Scout troops in New York City now have sets, mostly of the portable type for field use, but in addition some of the troops maintain power- ful tube sets at their headquarters. In many cases the sets have been designed and built by the boys them- selves. Scout Robert S. Dunham of Troop 501, Man- hattan, is responsible for one of the most efficient of these home-made sets. By an ingenious hook-up and panel plan, with jacks permitting the insertion of either head phones or microphone, he has concentrated his whole apparatus in a small rectangular box weighing less than ten pounds. The Scouts were active in wireless work even pre- vious to the recent radio boom. For a number of years now, a special radio award has been included on the list of Merit Badges given to Scouts acquiring specific knowledge of some sixty different vocational and avocational activities such as agriculture, signalling, plumbing, chemistry, printing, public health, crafts- manship, first-aid, business, civics, art, and electricity. And now the Radio Badge is worn with pride on many a khaki service sleeve. Boy Scouts Chronology of Speech Transmission by Wire and Wireless In its annual report to stockholders for the year 1922, made public last week, the American Telephone and Telegraph Company publishes the following inter- esting chronological table of events in the transmission of speech: 1875 First words transmitted by telephone. 1876 First complete sentence transmitted by telephone. First conversation by overhead line, 2 miles — Boston to Cambridge. 1880 30,872 Bell telepone stations in the United States. Conversation by overhead line, 45 miles — Boston to Providence. 1881 Conversation by underground cable, % mile. 1884 Conversation by overhead line (hard-drawn cop- per), 235 miles — Boston to New York. 1890 211,503 Bell telephone stations. 1892 Conversation by overhead line, 900 miles — New York to Chicago. 1900 676,733 Bell telephone stations owned and con- nected. 1902 First conversation by long-distance underground cable, 10 miles — New York to Newark. 1906 Conversation by underground cable, 90 miles — New York to Philadelphia. 1910 5,142,692 Bell telephone stations owned and con- nected. 1911 Conversation by overhead line, 2,100 miles — New York to Denver. 1913 Conversation by overhead line, 2,600 miles — New York to Salt Lake City. Conversation by underground cable, 455 miles — Boston to Washington. 1915 First conversation by transcontinental line, 3,650 miles — Boston to San Francisco. Speech transmitted for the first time by radio telephone from Arlington, Va., across the con- tinent to San Francisco, over the Pacific to the Hawaiian Islands, and across the Atlantic to Paris. 1920 11,795,747 Bell telephone stations owned and con- nected. 1921 Conversation by deep sea cable, 115 miles — Key West, Fla., to Havana, Cuba. First conversation between Havana, Cuba, and Catalina Island by submarine cable, overhead and underground lines ^and radio telephone — distance 5,500 miles. Extension of Boston-Philadelphia cable to Pitts- burgh— total distance 621 miles. President Harding's inaugural address delivered by loud speaker to more than 100,000 people. Armistice Day exercises at burial of unknown soldier delivered by means of loud speaker and long lines to more than 150.000 people in Arlington, Va., New York and San Francisco. 1922 Ship-to-shore conversation by wire and wireless between Bell telephones in homes and offices and the S. S. America 400 miles at sea in the Atlantic. 1923 14,050,565 Bell telephone stations owned and con- nected. Successful demonstration of trans-oceanic radio telephony from a Bell telephone station in New York City to a group of scientists and journal- ists in New Southgate, England. Digitized by Google

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6 RADIO WORLD A Simple Method of Winding Coils for the Flewelling Circuit By Arthur S. Gordon IF you are experimenting with the new Flewelling circuit as described in Radio World for Feb. 24, 1923, by Robert L. Dougherty, you will appreciate the simple method of winding honeycomb coilsv outlined in the following paragraphs. If you already know how to wind the coils, but are hesitating because of the difficulty encountered in mounting them, you will ap- preciate the novel and original idea suggested here, in tmcte or v*m» Fit. 1. Illustrating haw the cardboard tuba is prepared for the wind- ing and bow tba and of tha win is soldered to a copper nail which is afterward employed aa a contact for use with the adapter. which two copper nails and two contact clips from a discarded B battery are made to serve the purpose of the most complicated adapter. At any rate, this article is offered at this time because of the increased interest in that hook-up which not only achieves super-regen- eration with a single tube, but achieves it by the use of no more complicated a tuning device than the honey- comb coil. Not only in the Flewelling circuit, however, does the honeycomb coil find its ideal application. Long before super-regeneration was thought of, single circuit ama- teurs were using DL coils because they were so easily Fig. 2. Showing how the turn* are carried around the coil. Note that they jump two pegs instead of one as is usually the case. The winding goes over the nails and holds them in place. replaced with similar coils of a lesser or greater in- ductance. A set supplied with a complete row of honeycombs could jump instantly from 200 meters to 2,000 meters with no more effort than merely placing in the adapter that coil which possessed the required number of turns. This flexibility has given DL coils a deserved popularity in the past, and the new use for them in connection with the Flewelling super-circuit is bound to increase the number of amateurs who look with favor upon them. Possibly many of these enthu- siasts will be meeting the honeycomb winding for the first time; and for this reason, as well as for those given above, the construction of a DL coil of any de- sired number of turns is described and illustrated here- with in detail. A cardboard tube, two inches in diameter, is ideal for the form about which to wind the coils. Wound on smaller tubes, the coils do not function well, while the use of larger cardboard forms increases the linear amount of wire without adding anything to the efficiency of the coils. The same statements apply to the width, which should be about one inch. Of course, there is a little margin on each side of these dimensions which makes no difference whatever. .Measure off and mark on the tube two pencil lines one inch apart. Leave a margin of one-half inch be- tween the first line and the edge of the tube, because in this simplified method of winding where common pins are used as angle pegs, there must be extra card- board on both sides of the line. Before placing the double row of pins around the form, however, as shown in Fig. 1, stuff the tube with cloth or cotton, making it, in effect, a cardboard pin cushion. This padding gives strength and steadiness to the pins and effec- tively takes the places of the wooden cylindrical block usually employed. When the pins are in place about one-quarter inch apart, 25 pins once around, the form is ready for wind- Fig. J. The cod when finished. A cover of thin fibre is added for protecting tha wiadbig and also for appearance. Tha snaaBer afcatrh shows tha method of attaching the winding to the nails. ing. The right size of wire for coils of 50 and 75 turns is No. 22 or No. 24 SCC copper, although finer wire up to No. 30 may be, and is, used on coils of a greater number of turns. Before winding, solder the beginning of the wire along the upper half of a plain copper nail, which may be bought cheaply at any hardware store. Place this nail between any two pins with its lower part projecting beyond the second row of pegs, as shown in Fig. 1. A second and identical copper nail is placed in a like position on the other side of the coil, and both are, for the time being, held in place by a piece of twine. Later, of course, this twine is cut and thrown away, for every turn on the coil goes over these two copper nails and binds them as securely as though they were embedded in solid rock. It will be noted in taking the next step that .the turns go around two pins at a time instead of only one. It will be left to the amateur to discover the subsequent ease and neatness with which the turns fall in place. In detail, the winding is as follows: Take the wire from the first copper nail around the nearest two pins in the top row; then cross to the bottom row, at the same time making just one-half a turn with the tube. So around the two lower pins which imprison the sec- ond nail (see 2, Fig. 2) and then cross to the top row, this time also going around two pins, but including in (Continued on next page) Digitized by VjOO^ IC

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RADIO WORLD 7 Seven New Broadcasting Stations A "Tea Wagon" Radio Set SEVEN new stations were licensed to broadcast on 360 meters during the week ending March 10, 1923. They are located as follows: Call Station KFHA «1WJ O Let l K, 1\ Ul 11 Id 1 OClliiUIj Gunnison, Col. SO watts KFDX First Bantist Church Shreveport, La. 200 watts Greensboro Daily News, Greensboro, N. C. 300 watts WOAQ Portsmouth Kiwanis Qub, Portsmouth, Va. 15 watts WgAX Radio Equipment Co., Peoria, 111. 20 watts KFFO Smith, Dr. E. H., Hillsboro, Oregon. 5 watts WRAP Winter Park Elect. Const. Co., Winter Park, Florida. 20 watts Radio for Safety and National Welfare The use of radio for safety at sea and the welfare of the nation must be given first consideration in stand- ardizing services, according to Admiral Ziegemeier, Chief of the Naval Communciations Service. Dis- cussing precedence of the several services recently, Admiral Ziegemeier pointed out the necessity of grant- ing suitable wave lengths to the mobile stations, in- cluding ships and aircraft. (C Underwood and Underwood) Miss Florence Kiersted entertain* Mr. R. W. E. radio eet at the recent New York convention. ATTENDING the Second District Radio Convention recently held at the Hotel Pennsylvania, New York City, were many notables — in fact, so many that it would require columns of Radio World to describe them. However, out of all the chaos stepped a few to be meekly led before the "clicker" and snapped. It was therefore a fortunate moment when the photogra- pher caught Mr. R W. E. Decker, known on the "air" as 2VA, while seeking a few minutes rest from the ex- citement of the occasion. Mr. Decker is shown in the illustration listening to the "tea wagon set" demon- strated by Mrs. Florence Kiersted, of Brooklyn, N. Y. (Continued from preceding page) that number one that has already been used. In other words, although each turn goes around two pins, it only Fie*. 4. A sura-eeted way of mounting the coils when completed. Be cure to have sufficient space between the coils to allow them to turn and at the same time be in inductive relation. goes in advance of itself one pin at a time. Fig. 2 illus- trates this. When one layer is on the tube, you have wound 25 complete turns. Two layers contain 50 turns, while three make a DL coil of 75 turns. Whichever size coil you make, the winding should stop at the second nail and the end of the wire should be soldered to the flat head of that nail. Now take out all the pins except two, those two being the pegs about which the last half turn was taken. Soak the coil — also the working end of the tube — with hot paraffin. Wait until the paraffin is almost cold, then press it between the turns with your fingers. When this cementing process is finished, take out the last two pins, cut off the card- board on both sides of the now completed coil, put on a cover strip to protect the winding, and you will have a coil which looks something like Fig. 3. Now for the adapter. At some point during the preceding explanation, you have probably wondered what sort of an arrangement would take a coil with the ends of two copper nails protruding from it. Did you ever notice the terminal clips on a B battery ? Or the clips that are on sale in even the smallest radio stores, the kind that bend over, press down and leave a little bridge of spring brass under which to slip the wire or cord tip? Well, these contact clips solve the problem and solve it ingeniously. Looking at Fig. 4 you will find the stationary DL coil resting on two blocks of either wood or bakelite. The inner side of each of these blocks is one contact clip, so placed to receive the copper nail ends coming from the coil. The leads from the other instruments are, of course, soldered to the clips. That's novel enough and as simple as a device doing its work can be. The movable coil is served in a little different manner. The method of mounting the coil on a circular block of wood, which is in turn bolted to a brass rod, is inci- dental. The real purpose of the upper half of Fig. 4 is to show how the contact clips are soldered to flexible wires which go to the other instruments of the set, and which are clamped on the nail-end contacts. Digitized by Google

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8 RADIO WORLD An Improved Radiotron Type Vacuum Tube By J. L. Bernard ANEW and improved radiotron type UV-201-A superior in many respects to the UV-201 tube and designed to supersede the latter recently has been announced by the Radio Corporation of America, of New York City, as the latest addition to their vacuum tube line. While in outward appearance UV-201 -A resembles UV-201, with the exception of a slight discoloring of the bulb, the new tube incorporates several distinctive features. One of the outstanding features of the new tube is its special filament. Radiotrons UV-200 and 201 con- tain pure tungsten filaments which require about one ampere with a six volt battery source for the produc- tion of normal filament emission. The latest tube, however, contains a new and improved filament requir- ing only one-quarter of an ampere (.25) at five volts across the terminals of the filament and with this cur- rent the filament emission averages about five times that of the UV-201 tube. It is remarkable that with MFD OHIO Putt Fie I DETECTOR FIG 2 AMPLIFIER Diagrams lUuatratiB* Method of Using Radkrtrcra Tub* a* Detector this special filament, the electron emission is increased five-fold and not, as one might expect, at the expense of additional filament power. Furthermore, this high filament emission is not accomplished at excessively high operating temperatures. On the contrary, the filament, when burning at normal brilliancy, has a tem- perature materially less than that Cf the UV-201 tube. Aside from its superior filament properties, the new tube is exhausted to an exceedingly low pressure. A high vacuum is recognized as representing one of the most important factors in the design of vacuum tube amplifiers and every effort has been made in the case of UV-201-A to completely expel the gases from the bulb. The successive stages in the exhaustion of the new tube are carried out with extreme care so as to insure satisfactory performance. During this process of exhaustion a mirror-like film collects on the inside wall of the glass bulb which re- mains after the exhaustion is completed. The trans- lucent film should not lead the owner to believe that the tube is defective. This slight discoloring does not interfere with the operation of the tube in any way. High filament emission in a vacuum tube, when ac- companied by exhaustion which is carried to the low- est pressures obtainable in production determines, in a large measure, the success of the tube as an amplifier of radio-frequency currents as well as low frequency energy. The practical significance of these features is : (1) F1 emission from the filament, averaging about five times that of the ordinary amplifying tube, make it an exceptional tube for power amplification such as that required for loud speaker operation. (2) The filament of one tube consumes one-quarter ampere and it may be operated from four dry cells in series thus eliminating the use of storage batteries. If more than one tube is used, it is recommended that a storage battery of from 20 to 40 ampere-hours be employed If radiotrons — UV-201-A — are used instead of UV-201, the battery will last four times as long. (3) Having exceedingly high vacuum, the tube is exceptionally quiet in operation there being no inherent tube noises. High vacuum also assures uniform characteristics. (4) It is particularly adapted to radio-frequency amplification. (5) In its operation as a detector, radio-frequency or audio-frequency amplifier the results obtained are exceptionally independent of filament ad- justment. Critical adjustments of grid leak or grid condenser are not required. (6) It can be used in any equipment which at present uses the ordinary tube and will give improved results. No adapter is necessary when the standard four-prong socket is used. (7) If the filament is supplied by a six-volt battery the resist- ance of the filament rheostat should be at least four ohms, preferably six ohms. (8) Filaments should al- ways be operated at the lowest current consistent with satisfactory results. (9) The tubes should be mounted on cushioned bases when used for detection and audio- frequency amplification. When the tube is used as a detector it is usually preferable to connect the grid return to the positive side of the filament exactly as shown in Fig. 1 here- with. A grid condenser of .00025 mfd. and a grid leak of two to five megohms are recommended. Critical adjustments of grid leak and condenser are not re- quired. The best plate voltage for detection is ap- proximately 40 volts. When the UV-201 -A radiotron is used as an amplifier it is important that the filament rheostat should be placed in the negative lead from the "A" battery and that the return lead from the grid circuit should be connected to the negative side of the "A" battery and not to the negative side of the filament. These con- nections should be made as shown in Fig. 2. For the best results the negative grid bias voltage should be increased with increase in plate voltage. I« general, the following grid bias voltages are suitable: 40 volt plate, 0.5 to 1.0; 60 volt plate, 1.0 to 3.0; 80 voh plate, 3.0 to 4.5 ; 100 volt plate, 4.5 to 6.0. Negative biasing cells should always be placed a that portion of the grid circuit where it returns to the filament circuit rather than next to the grid terminal of the tube. What Most Appeals to You in Radio World? Drop us a line and let us know what you like u>i what you don't like in our text page*. We are trymt to keep our thumb close to the pulse of the rtcfopwot Judging by the sales of this paper, we are Let's hear from you. Address Editor, Radio Worn, 1493 Broadway, New York Gty. Digitized by Google

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RADIO WORLD 9 Prize Winning Amateur Set at Radio Fair, New York THE amateur constructor, in the making of his set, is taking more care and pains than was his wont in the old days. This has been proved conclusively in the many sets which have come forward at recent con- ventions and fairs where various amateurs exhibited their work. It used to be that when a fan was making a set, any old thing he found lying around would serve the pur- pose as long as it worked, even half way. This has given way to the man who, with electric soldering iron, automatic drill, templates and the best of material, is making the most up-to-date circuits for his own use. His workmanship is excellent, frequently surpassing that of the professionally manufactured article in point of novelty and idea, if not in work alone. Of course the hand-made set must of necessity give way to the machine drilled and assembled set, but for work where care has been taken and ideas worked out in concrete form, the American amateur who makes his own set is without peer as a model maker. An example of this fine type of workmanship is the set illustrated herewith, which was constructed by W. H. Spalding, of Brooklyn, N. Y., and which won first prize at? the Amateur Set Contest of the Permanent Radio Fair, Hotel Imperial, New York City. The judges had many sets to test and look over. After due consideration the prize was awarded to Mr. Spalding for workmanship, novelty and actual working qualities. The set was entirely constructed by Mr. Spalding who used the three unit honeycomb circuit, embodying sev- eral new ideas in the construction of the set, such as the elimination of the jacks and plugs for the switch- ing of the phones from the detector to the different stages of amplification. This was done by means of (C Fhotoaews) W. H. Spalding and the dint tube receiver with which he won Ant pries at the Permanent Radio Fair, Naw York City. The set operates en die famous 1% volt ceDe. Transfer from detector to Arat stage and first stage to second la made by an ingenious arrangement of push switches, mstead of the regulation plug and Jack. The set is seH-csDtained, haying apace for the batteries in the cabinet. It won on points of utility as well as work- manship, the Interior being wired with utmost care. two small push switches, and embodies several novel constructional details evolved by the builder in the course of his work. (C. Kadel & Herbert) Chief Petty Officer W. L. Wbalen tuning in Pittsburgh at the Motor Boat Show, New York City, where the radio division attracted much at- tention. The set shown is a De Forest Reflex with Magnavox loud speaker. Radio at the New York Motor- Boat Show ONE of the most interesting exhibits at the recent Motor Boat Show, Grand Central Palace, New. York City, was the radio booth. Here gathered all the "old salts" even if they only owned a row boat. Some, of the radio sets, designed for use on small yachts, at- tracted much attention, but on the whole, the most at- tractive was the one incorporating the loud speaker through which music from the different broadcasters was heard. Of course, nobody who owns a yacht, cat- boat or small motorboat can be considered up-to-date these days, unless they incorporate a • full-fledged radio receiving, and maybe transmitting, set on their craft. The delight of "sailing, sailing, over the bounding main," is not complete these days unless refreshing music from one of the larger broadcasters is to be heard. Think of the comfort of knowing that you are always in touch with land, no matter how sea-sick you are. Many amateur yachtsmen have also become enthusiastic radio fans and are building their own sets for use on their craft. Broadcast Test Between London, England, and Newark, N. J. REPORTS from British fans telling of the reception of American stations in England has influenced the British Broadcasting Corporation to arrange for a special program in an attempt to reach the United States. Tentative arrangements had been made between 2LO, which is the main station of the broadcasting chain controlled by the corporation and WJZ, the Radio Corporation-Westinghouse station in Newark, N. J., for reception of the former's program early in April. As a new station is being erected by the Broadcasting Corporation which will be more powerful than the orig- inal one, the test has been postponed. Station 2LO will conduct its tests with WJZ on 360 meters, which will enable fans equipped with broadcast receivers to tune in that wave to listen in. The New- ark station will stand by during the test, and the co- operation of other local stations will be asked. Digitized by Google

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10 RADIO WORLD The Kenotron Rectifier for Obtaining High Voltages By B. R. Cummings Radio Engineer of General Electric Company THE development of three-element vacuum tubes for use as generators of radio frequency power has been accompanied by the requirement for a power supply of high voltage direct current, which is applied between the plate and filament of the three-element tube. At lower powers the high voltage direct current is obtained from a direct current generator with a rotating armature. At higher voltages than are ob- tainable from such machines, however, it has been necessary to develop other means for obtaining this supply. The kenotron rectifier has been developed primarily for this purpose in connection with radio telephone and telegraph transmitters, although it is applicable to other uses where a high voltage direct current power supply is required. ■The word "kenotron" was originated by the General Electric Company about 1913 as a name to cover all types of vacuum tubes. The word is derived from two Greek words, "keno" and "tron," the former meaning space or vacuum, and the latter meaning object or thing; the word kenotron, therefore, implies a vacuum device. As used at present, the term refers only to the two-element rectifying tube, the term "pliotron" being used for the three-element tube. The kenotron is similar appearance to the more familiar three-element vacuum tube, the underlying difference being in the omission of the third or control electrode, commonly known as the "grid." In one of its earliest forms it was known as the "Fleming valve," although that valve was built for handling comparatively small currents only, and was used almost entirely as a detector tube in radio receiving circuits. The kenotron depends for its functioning upon its inherent unidirectional conductivity, which briefly may be described as, follows: In common with the more familiar three-element tube, a filament in a highly evacuated vessel is heated to incandescence by the passage of direct or alternating current through it. Under these conditions the filament emits a great num- ber of electrons, which are unit charges of negative electricity. If a potential difference is created between the filament and the second electrode, known as the "plate," and the plate is made positive with respect to the filament, the negative electrons will be attracted to the plate and will enter it, causing a flow of current between the filament and plate inside the tube and from the plate back to the filament in the circuit external to the tube. The flow of current, therefore, is based fundamen- tally on two things. First, on the continuous emission of electrons by the filament; and, secondly, by the attraction of these electrons to the plate. It is appar- ent, therefore, that the current in such a device can flow in one direction only; for if the plate is made negative with respect to the filament, in an effort to cause a current flow in the opposite direction, the fact that no electrons are emitted by the plate will leave no medium for current flow in the space between the fila- ment and the plate. Under these conditions, the result is an open, circuit. As soon as the potential of the plate again becomes positive, however, current will again flow through the tube. Therefore, if a kenotron tube of suitable capacity is placed in series with an alternat- ing current supply, it will be found that current will flow in the circuit only during every other alternation, during which the current flows from the filament to the plate. For the alernations which would normally cause the flow of current in the opposite direction, the kenotron acts as an open circuit. The output of such a rectifier will be a pulsating direct current, each successive alternation of the power supply, of the same polarity, producing a pulse of direct current. It is customary, therefore, where direct cur- rent of constant amplitude is required to add a so-called "filtering system" in the output circuit of the rectifier, which will smooth out the ripple. For the, production of high voltage direct current by means of a kenotron rectifier, it is customary to step- up the alternating current supply voltage, by means of a transformer, to a voltage somewhat higher than that actually required for the operation of the three-element pliotron in the radio transmitter proper, so as to allow sufficient additional voltage to compensate for the vol- tage drop through the kenotron tubes and the filter system. This high voltage alternating current is recti- fied by means of kenotron rectifiers, the circuits and the number of kenotrons used depending upon an econ- omic consideration of the purposes for which the equip- ment will be utilized. It is possible, by means of a number of kenotrons, and by utilizing a multiplicity of phases, to obtain a direct current output from the kenotron rectifier which will have remaining in it only a small percentage of intermittent direct current. Particularly in the radio telephone transmitter it is essential that the plate supply to the pliotron tubes be constant, and it is customary in such equipment to associate with the kenotron rectifier a filter system. Here again the extent to which the filtering is carried out is dependent upon economic conditions, and it is usually found that it is preferable to permit a very small ripple in the output rather than provide a filter system which would be sufficiently elaborate to remove this ripple entirely. Such filter systems usually consist of a combination of .condensers and reactors of com- paratively high capacity and inductance connected across, and in series with, the load. In some cases it is found that a "trap" circuit, consisting of a capacity and an inductance in parallel, tuned to the frequency of the ripple in the rectified output, can be effectively used to suppress the ripple. The kenotron rectifiers built on this principle are applicable not only to radio equipment, but to any cir- cuit in which a high voltage direct current is required. Such rectifiers have been built with capacities up to 30 kilowatts at 15,000 volts direct current, although much larger equipments can be developed. Such equipment is preferable in many respects to revolving machinery, even at voltages at which the latter can be built. The kenotron rectifier is noiseless in operation, has no moving parts and requires no maintenance other than the infrequent replacement of the rectifier tubes. Digitized by Google

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RADIO WORLD 11 Capital Radiations By Washington R. Service [ WASHINGTON, D. C— For the first time an army order directs an officer to report his ar- rival in this country by radio. Ordinarily an officer is advised to report by telegraph or in writing, but today radio has begun to usurp other means of communication and the order quoted is an indication of future practice. Major A. B. Hitchcock, of the 7th Infantry, who has been ordered to return from Alasks to the States, was the first officer ordered by radio to report to his new commanding officer for assignment. * * * An investigation to ascertain whether or not there is will be undertaken and contracts and agreements will be examined to learn if exclusive rights or special privileges for transmission or reception have been made. No announcement has as yet been made by the Commission. * * * Radio will play an important part in the Interna- tional Ice Patrol Service which will begin for the sum- mer as soon as the Coast Guard cutter 'Tampa" leaves Boston. The purpose of this service to which the cutters "Tampa" and "Modoc" have been assigned by the Coast Guard, is to locate dangerous ice near the Radio Entertains the Bedridden New Use for Phonograph Records (C. Gilliams Service) About the me— t fate la the world la lying In ■ hospital, unable to move, and dapondfag upon people to brine a little sunshine into your with flowere and a little gossip or the life in the conventional outside world. That is as it used to An up-to-date case la mat of W&Vam recently suffered broken arms and legs m a fall but is not at the high tslsphons pole. His comrades, hearing of his ought, that he was an especially active man, understood mat from his forced inactivity. So a particularly t man, unden they installed he would suffer a radio set in bis A Fire Escape Antenna WLML § i. L •if" I : •* I (C. Kadel and Herbert) _ An unusual DX accomplishment accredited to A. S. Mawhinney, Ml Rivereide Drive, New York City, recently was described in RADIO WORLD, and now the fane are given a chance to sss the workings of this remarkable est. This set picked up California, using a wire attached to the fire escape as an antenna. The set illustrated, it will be noted, usee five tubes— the first two on the right aa radto frequency ampufters, the third tube as a detector, and the two V. T. Is aa audio frequency amplifiers. The work of this set hj a marvel, aa la also the work on it. (C International Newrreel) One of the newest wrinkles m the way of .__ was recently shown by W. J. Simpson, of St. Paid, Mian. , lot of obi phonograph records which had outaved their usefulness, ha ratua, This, of course. Is not tried uamg them for ~~""-t radkt rEkvfag'a to work with, and are good insulators, being A neat cabinet for this type of apparatus c • Mademoiselle, the Modiste, sends boms to tout be painted black and no one will know the dUTs a radio trust will soon be launched by the Federal Trade Commission in compliance with the require- ments of a House resolution. This resolution directing the Commission to investigate the status of the radio industry to ascertain whether anti-trust statutes were being violated, was received by the Commission last week. It is understood that a conference of the officials and probably a preliminary investigation will be held before formal action of any sort is taken or witnesses are called. A complete survey of the radio patent field transatlantic steamship lane, patrol the section and broadcast warnings twice daily on 600 meters. The ship on patrol answers to the call KFOG and gives in- formation upon request. Once each evening a radio- gram is sent to the Hydrographic Office of the Navy in Washington defining the ice danger zone. This in- formation is re-broadcast from naval radio stations at Arlington, Annapolis, Boston, New York and Norfolk every morning and evening because the ships' apparatus is not powerful enough to carry long distances. Digitized by Google

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12 RADIO WORLD Methods of Measuring Properties of Electron Tubes A Convenient and Readily Determined Detection Factor Various detection factors have been proposed* to express the merits of the electron tube as a detector. A factor to be useful should be readily determinable and simple of application in desired calculation. The audio-frequency output voltage (or current) produced by the rectification of a completely modulated radio-frequency input varies for most detector tubes over a limited voltage range approximately as the square of the input voltage. So for a load of given impedance in the plate circuit the ratio of the voltage across this load to the square of the input voltage will be nearly a constant over this limited range of voltages. This ratio forms a convenient detection factor, which may be readily determined with the tube under actual operating conditions. (This factor is used in cal- culations by L. M. Hull in the report mentioned above.) The method of measurement can be understood by reference to Fig. 6. It consists of applying a completely modulated radio-frequency voltage to the input of the tube and measuring the audio- frequency output by comparison with a known audio-frequency voltage of the same frequency. R, Radio- frequency link resistance. Rt Decade resistance box, 0-1,000 ohms. R, Resistance box, 0-10,000 ohms. V. Hot-wire voltmeter, 0-30, 0-150 volts. The tube and measuring apparatus are completely enclosed in a grounded screen wire cage, which shields the apparatus from the radio generator and from stray radio signals or disturbances, and is supplied with modulated radio - frequency and audio - frequency current from apparatus outside of the cage. The modulated radio frequency is supplied by an elec- tron-tube, radio- frequency generating set, enclosed in a metal-lined box and placed about 3 meters from the cage. The wave length of the generated radio frequency is variable over the range desired. The plate voltage is about 120 volts alternating current, supplied by a small 500-cyde motor generator, which also furnishes, through a step- down transformer, 30 volts to the leads 2. The radio frequency, adjusted to the wave length at which measurements are to be made, is introduced into the cage by means of coils L, and L„ the coupling of which FIG.6. SlMPUFED DIAGRAM OF CIRCUIT FOR MLA3URLMLNT Or OtTCCTiON TACTO*? The complete circuit arrangement is shown in Fig. 7, in whjch the following legends are used : 1. Leads to radio-frequency supply. 2. Leads to audio-frequency supply. 3. Terminals connected to input of tube under test. 4. Terminals connected to input of tube under test. 5. DPDT switch. 6. Galvanometer shunt. 7. Vacuum thermoelement of low resistance. 8. 3-stage audio - frequency amplifier (resistance coupled). 9. Audio-frequency transformer. 10. Grid leak, 2 magohms and 2.5-volt battery in input circuit of amplifier. 11. Mica condenser, 0.02 microfarads capacity. 12. Crystal detector (carborundum). (These may be replaced by thermoelement and galvanometer.) 13. Milliammeter. 14. Filament battery terminals. 15. DPST switch. C. Variable condenser, maximum capacity, 0.005 microfarad. G. Sensitive galvanometer (low resistance). Lx and L, radio-frequency coupling coils. •Stuart BallaaUae, Proc. I. R. E., April, 1919. L. M. Hull. Radio Laboratory Rnport, Bureaa of Standards, CR134d. John R. Canon, Proc. I. R. ■., A»r< * nulbert a Brett. Phys. Rev.. 16, 1820. p. 274 and p. 4*6. H Btjl. "Thermionic Vacuum Tube»," p. 339. can be varied. The coil L„ outside the cage, has an inductance of about 140 microhenries, and, since it is in an untuned circuit, is used over the entire range of wave lengths. Two coils are used at in the tuned circuit, L,-C-15-7-R, inside the cage, to cover the range of wave lengths required — one the same size as L„ used from 600- 1,500 meters, and a larger coil having an inductance of about 860 microhenries, used from 1,500-4,000 meters. This input circuit is tuned to the radio-frequency current in L, by varying the condenser C. The input to the tube is the iR drop across the resistance R, due to the radio-frequency current flowing through R and is varied by using different values of R and varying the current through R by changing C. This current is measured by the thermoelement 7 and galvanometer G, which are calibrated with the shunt 6. The resistances used at R are standard high-frequency link resistances,* varying from 0 to 30 ohms. They must be measured occasionally on a direct current bridge to check their re- sistance as they do not remain constant. The grounded input terminal at 3 may be connected to either the negative or positive side of the filament Short leads should be used in all connections to the tube. The audio- frequency comparison voltage is supplied to the switch 5 through shielded leads by the voltage divider •See Bureau of Standards Circular 74, p. ITS. (Continued on next page) Digitized by Google

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RADIO WORLD 13 Prof. Hazeltine Demonstrates His New Neutrodyne Circuit A . DEMONSTRATION of the neutrodyne circuit designed by Professor Hazeltine, of Stevens In- stiute of Technology, was given last week at Columbia University, New York City. Its principles were fully explained by the inventor and by its builder. This re- ceiver operates on an entirely new principle and because of that fact, it is incapable of oscillating. It is known as the "set that cannot cause interference through its re-radiating signals and oscillations." The circuit utilizes two stages of tuned radio fre- quency, detector and two stages of audio frequency, but through the agency of an entirely new design of several of the component parts of the receiver, it may be said to be one of the revolutionary models of radio receiv- ers. The signals received are of such volume that it is possible to receive them without either antenna or ground. As demonstrated at Columbia, the clearness of the received signals was on a par with crystal de- tection, no distortion or other extraneous noises being noticeable. The signals came in with perfect modula- tion, a feature of note in itself, as many of the regener- ative circuits of today distort music and the voice to such an extent as to make them totally unrecognizable when they are amplified to any great extent. This receiver marks one of the greatest advances made in the design of receiving apparatus so far, and will tend to revolutionize the designs of receiving ap- paratus. The circuit is licensed for manufacture to the Independent Radio Manufacturers, Incorporated, and will shortly be placed on the market. As explained in RADIO WORLD for March 10, 1923, in which a descriptive article appeared with ? illustration of the receiver, one of its great advantages is that it will tend to decrease the interfernce in re ceiving due to nearby receivers re-radiating signals and causing the receivers in the vicinity much trouble es- pecially when faint signals are being received from far distant stations. The interference of one set employ- ing the regenerative principle, with two or more steps of audio frequency and at least 100 volts on the plate can be felt for quite a distance, especially in the case of a section of the country where there are a great many sensitive receivers located in a small congested area, such as the residential districts of New York, where there are often 50 to 100 tube receivers located within a space of a city block. Any one familiar with the diffi- culties of reciving DX signals in such a section, will realize the benefit of this type of receiver. It is often (C. Kadel & Herbert) Demonstration at Columbia University, New York City, of the ne- dyne circuit designed by Prof. Hazeltine (left) and built by J. D. R. Freed (right). The audience overflowed the room and many had to be turned away. possible for a crystal detector to be set oscillating through the agency of a powerful regenerative set in the vicinity, through the heterodyne principle which uses a separate oscillator to enable a non-oscillating detector to receive undamped oscillations. When the Hazeltine circuit, or neutrodyne receiver, comes into popular use all this will be eliminated, be- cause of the fact that the receiver does not depend upon oscillations for its effective operation. (Continued from preceding page) at Rj R,, consisting of a resistance Rt variable by one ohm steps from 0-1,000 ohms, to which are connected the leads into the cage, in series with resistance R2 variable from 0-10,000 ohms in 10 ohm steps. The voltmeter V and supply voltage from the 500-cycle generator are con- nected across Rt R2 as indicated. When either the audio-frequency output voltage of the tube under test or the comparison voltage obtained from the voltage divider is connected to the input of the voltage- indicating circuit by switch 5 it is amplified by the 3- stage audio-frequency amplifier 8 and transformer 9, caus- ing an alternating current to flow in the circuits 9, 12, 13. This current is rectified by the crystal detector 12, and deflects the milliammeter 13. With the frequency of the radio-frequency generating set adjusted to the desired value and switch 5 up resistance links are inserted at R, always opening 15 before removing a link at R, increasing R until a suitable deflection is obtained on the milliammeter 13. The comparison voltage is now connected to the voltage- indicating circuit by throwing switch 5 down, and R, and R, are adjusted until approximately the same deflection on the milliammeter is obtained as previously. Switch 5 is thrown to the up position again and the tube input varied by varying C, it being equipped with a small variable con- denser for fiae adjustment until exactly the same deflection is obtained with switch 5 either up or down. The audio output voltage et is now equal to the comparison voltage across R„ and, since the voltage E across R, and R„ measured by voltmeter V, is known, the tube output voltage — e, = E R, Rx + R, The galvanometer being calibrated, the current i, flow- ing through R is obtained from the galvanometer deflection, and the radio input voltage — e, = i R From the definition given above the detection factor k= et These measurements are repeated at different frequencies if desired. This detection factor has the disadvantage that it must be specified with a given load in the plate circuit. How- ever, for a comparison of several tubes this load may be kept constant, and a good factor for judging the tubes is given. (This is the third and hat of a series of three article*. The other two appeared In RADIO WORLD for March M and March 17, IKS.) Digitized by Google

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14 RADIO WORLD The Radio Primer For Thousands of Beginners Who Are Coming Into Radio Circles Weekly A B C of Radio Facts and Prin- ciples Fully and Clearly Explained By Lynn Brooks T"Y 7" HAT is meant by "shielding a panel"? I/Mf By shielding a panel is meant to line the r F side with a metallic sheet, in order to elimi- nate the bothersome "body capacity effect" which is so noticeable when a regenerative circuit is employed. This body capacity is an annoyance because when tuning a set which is not shielded, the set actually can be thrown out of tune by removing the hands, placing the hands near any of the major controls and oftimes by grasping the phone cords. This can be eliminated by shielding the panel. * * * How should a panel be "shielded"? The method of shielding a panel is as follows : Take a sheet of heavy tin-foil, copper-foil, or thin sheet aluminum, and mark it for drilling the same as the panel. This is done easiest by first drilling the panel itself. Then using the panel as a template, drill the metallic sheet, being careful to drill all the holes in the shield itself larger than those of the panel. This is done to prevent any of the metallic parts of the in- struments coming in contact with the shielding and shorting through the agency of the machine screws with which the instruments are themselves fastened to the panel. Then . either using a heavy shellac or small machine screws, fasten the shielding in its proper place on the rear of the panel, making a connection from the shielding to the ground. If tinfoil is used, it is best to allow a lug to remain on the sheet and then fasten this under the ground post. If you try to solder on tin foil you will be disappointed as it is almost impossible. If copper foil or aluminum is used they can be soldered. * * * What parts of the panel should be shielded? In the shielding of a panel it is only necessary to shield the parts of the panel that house the tuning controls, such as the variometer, variocouplers or . tuners. The detector and amplifying units do not have to be shielded. In some of the commercial sets the units are shielded separately. There is a separate shield for each variometer, tuner, condenser, or other tuning unit. * * * Is shielding necessary on all sets? Shielding should be used on all sets employing re- generation. The straight audion does not need this so much, as the capacity effect is not so noticeable. * * * How can it be determined if shielding is necessary? If when the set is tuned and the hand taken away from the controls, the signals fade appreciably or are lost altogether, that is an indication that the body capacity has been called into effect when tuning, and immediately when the hand has been taken away, it has disappeared. In this case, the panel of the tuning unit should be shielded, or if that is not advisable, a "long-armed control" should be employed. RADIO WORLD'S ANNIVERSARY NUMBER NEXT WEEK RADIO WORLD is hard at work on its Special An- niversary Number, dated March 31, published March 28. This issue will celebrate the beginning of the third volume of RADIO WORLD, the great national illus- trated weekly. The red advertising form has gone to press. , Last page of last black form closes March 23. Regular advertising rates are in force as follows: One page: One time— $150.00. Half, Ouarter, Third and Two-thirds pages at proportionate rates. One inch, one tune— $5.00. Per agate line, $0.40. On four consecutive issues, 10 per cent discount. On thirteen consecutive issues, 15 per cent discount Cover and preferred position rates made known on application. ■Write or send copy and order now and get the best possible publication value by being represented in the Special Anniversary Number of RADIO WORLD. NOTICE TO READERS — Orders received indicate a great demand for this Anniversary Number. We have tried to provide for this in advance. If you want to be sure to get RADIO WORLD for March 31, leave an order with your newsdealer. RADIO WORLD, 1493 Broadway, New York City. Radiograms The Nary Department will offer two engineering students from each of the country's leading universities the opportunity to cruise for two weeks on navy vessels. The plan will go into effect next summer to allow students to study the mechanics, electrical apparatus and radio equipment of warships. * » » Fire destroyed Shepard's department store in Providence, R. I., last week, with a loss of $1,500,000. The store's radio was broadcasting a concert when the flames were discovered. After sending a message that the entertainment must stop because the store was afire the twenty entertainers escaped to the street * * * Jackie Coogan, the seven-year-old motion picture star, addressed the radio audience of WGY, the Schenectady radio broadcasting station of the General Electric Company, on March 23. Jackie's voice was photographed by the pallophotophone a few weeks ago and this record was reproduced by radio. Jackie, now back in Los Angeles at work on a new picture, heard himself, talk across the continent. As he explained : "I got quite a thrill from hearing myself talk to myself three thousand miles away from myself." The extent of the great interest manifested in radio was indi- cated in St. Louis last week when a large advertisement appeared in the newspapers of a 54-apartment building just being completed, in which every apartment is supplied with complete radio equipment * * * Columbia University has placed at the disposal of the Ameri- can Institute of Electrical Engineers a scholarship in electrical engineering in the School of Mines, Engineering and Chemistry. Reappointment of the student is conditioned upon good standing. Francis Blossom, F. B. Jewett and Professor W. I. Slichter have been appointed as a committee to pass upon the fitness of applicants. * * * Through arrangements with the American Telephone and Telegraph Company radio station, WEAF, Arthur Hammers tem, who is at Palm Beach, Fla., was the first theatrical producer to listen in on his own production. On Thursday evening, March 15, a special wire was installed at the Casino Theatre, New York City, where the producer's musical play, "Wildflower," is the attraction, and the entire performance was broadcast from overture to finale. Incidentally, it is said that this is the first time an entire produc- tion has been broadcast. During the intermissions of the piece a synopsis of the play was given so that the radio audience would receive the full benefit of the performance. Digitized by Google

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RADIO WORLD 15 Radio and the Woman By Crystal D. Tector MY best friend and myself had a terrible argu- ment the other day because of the fact that 1 went to the Third Annual Radio Convention and didn't call for her. I had told her that I intended going, and when I came home, of course a lot of my friends wanted to know how the show was. I was all properly enthused and of course she heard about it. Just because I hadn't told her that I was going, she went off in a huff and said she wouldn't go. Well, I have heard of silly people biting their noses off to spite their faces, but this is even worse. I would have par- doned my worst enemy to go to the show. And F. H. is sore at himself because he couldn't get tickets for the banquet. * * * I notice that a station is giving out information on household budgets and how to cook various little dishes that are not heard of much these days. I never knew how to make "Floating Island" until I heard the little lady tell how, and so I surprised F. H. that night by having it for supper. When he asked me what it was I replied : "Well, that's the newest radio develop- ment, called 'Hetrodyne Pudding.' and I really think that he believed me." Friend Husband came home one evening all excited and wearing a big mysterious smile. Under his arm he carried the funniest looking long parcel, like the old fashioned French bread that you used to get when Old New York was young. I tried to make him tell me what it was, but all he would say was, "Wait a while, nosey; don't get impatient, or I won't show you." Well, the only thing that I could do was wait and you girls know how a husband can be mysterious when he wants to. Teasing won't do any good with F. H. 'cause he just assumes that legal air and freezes right into his shell. After dinner, he sneaked up into his room and I heard him hammering and puttering around and I tried to get in but he had locked the door. I went down and started in to finish my novel, or listen in, I forget which now, because I was so full of curiosity that I really couldn't digest anything that I was doing or trying to do. After about an hour, I heard the up- stairs door open and F. H. come sneaking softly down. I never moved, or tried to even peek. He passed the parlor door and went down stairs, and pretty soon I heard him slam the furnace door. When he finally re- turned upstairs, he was wearing a very disappointed look and he finally delivered a lecture to me on the subject of "If dumbells like me didn't believe every- thing that people told them, then the wjse men^that sting them with radio sets in a cane — you don't even need an antenna — wouldn't be able to earn enough to make the price of a cup of weak tea," and so on. It was quiet evident that even a wise "radio man" like F. H. can be fooled by a slick salesman some time. The best way, I think, of providing against that is to have the thing demonstrated right there and investigate it be- fore you even think of buying it, even if it does look good. * * * 'Member last week I told you about my "home-made Flewelling?" Well, I think that we have had more fun and heard more different stations with that "funny f looking contraption," as Brother-in-law Jack says, than with any set I have ever had before. I can have more fun playing with the different squeals and howls and then tuning them into WLW or one of those DX stations to the complete mystification of all my friends. It really is a most complete education to try to make a set by yourself and then succeed after numerous and grievous set-backs, such as burns, wrong connections and other things too numerous to mention, but always interesting to look back upon. I always remember my first attempt to make a dress and a cake, and I always will remember my successful attempt to make a Flewelling. Radio Equipment in a New York City Armory Interior of Station BC4, located at the llUt Signal Battalion Armory, Park Avium and 34th Stmt. Nov York City, showing the and receiver used, with tha loud speaker, directly next to which im the power amplifier enanBac the signals to be heard "" Urge room. The picture to the right •hows toe charring panel, which keeps the batteries at full charge at all time*. Digitized by Google

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RADIO WORLD Photographic Glimpses Captions by Rot (C. Photonews, N. Y.) A neat and compact receiver which attracted considerable attention at the Permanent Radio Fair, Hotel Imperial, New York City. It wae mounted on the base of a regular sachet. The tuning inductances, as can be seen, are spider- webs, and comprise tile entire tuning unit of this unique receiver. (C. Kadel and Herbert) B. R. Mayo, U-year-ei his marvelous sat, whs for leas than VMM, ye( over \jttt miles. It reqi to receive signals. It wi (C. Kadel and Herbert) Colds Gray, nationally known dancer and "Follies Star," on a visit to the recent Radio Exposition, finds the radio teapot the most interesting thing there because of the fact that it "let's one have music with one's tea." The set in question is buOt into a teapot and has a range of 1,M miles. It utilizes a peanut tube for reception, with compact wound Inductances, allowing the entire set to be mounted atop a silver tea pot, as seen in the picture. (C. Wide World Photos) One corner of the Research Bureau of the Berlin National Departmental Wireless Telegraphic and Telephone Co., Berlin, Germany. This office is experimenting with the advisability of long distance re- ception and transmission on small loops. The signals received are automatically registered on a moving tape, aa can be noted in the picture. :. P. & A. Photos) aptain Maurras, of the S. S. Paris, talking to Captain Roch, of the . S. Franca, more than 2Sa mflai distant. This Is one of the advantages radio to captains of ships sailng the high eeas, It allows thun to inverse with much less trouble than on land, because there is no ratral to get the numbers mixed up. The radio telephone has bee— a > important to "those who roam the watery lanes" that its importance is only eclipsed by the machinery of the ship Itself. (C. Wide World Photos) Unique method of control to capacity, need in the Research Bureau of the Rerun National Wireless Department. The receiving In- struments are so super sensitive that the lanliul is accomplished at a distance by means at strings (C. Keystone View Co.) The receiving antenna at which Is one of the prince, European signals handbd America. The antenna b a is nine mass hang. Mr. E. Digitized by

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RADIO WORLD 1 mm the Realm of Radio ■t L. Dougherty tsdio enthusiast, and can be made to sell ahich has a ranee of • no outside antenna Cerate a loud epoah- aate the fact that a i 1 stations y the r M feet W. la ' Y„ of of but (C Kadel and Herbert) When yeu hear J. E. K. announcing at WOR, you know it is a woman, but few of you West- erners have ever seen her, and that same ap- plies to a great number of the local Eastern fans, so an introduction is in order. Therefore, "Radio fans, meet Miss Jessie E. Koweing, one 'of the official broadcasters of Station WOR." (C. Kadel and Herbert) Some of you fans have often wondered who originated the term "cat whiskers." If you will look at the above picture you will see the originator and possessor of the finest cat whisk- ers in the land. All hail the "Radio Kink of the Cat Whiskers." The speech by Secretary Herbert Hoover, arbiter of radio telegraphy and telephony, which re- cently broke all distance records of KHJ, the Los Angeles station, Mr. Hoover's speech from that station was heard SN muss east at New Ygrk City, a durtance af ijm mOat, and was a ------ isav. The picture an that (C. Kadel and Herbert) A fair fan's idea that saves a lot of worry when she shuts off for the evening. Miss Margie O'Ncil found that she sometimes went to her downy and forgot to turn the current off her Magnavox, with the result that the , battery was run down the next morning. So she placed a small six volt to "turn off." .amp in parallel with the battery line, which warns her » ■ (C. Harris and Ewing) W. W. Tapper, of the Bureau of designed to make it possible for , . in touch with the outside world. The set uses three spider web tad ad a WD-U aa a detector. Aa the Bureau has Lighthouses, and the of isolated lighthouses to keep be furnished by the B to al keepers dseirtog =— = win

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18 RADIO WORLD Answers to Readers TTflLL you give me a hook-up for the rr Reinarts circuit using honeycomb coils, and also the proper site coils to usef 2. What is the correct spelling of the name? 3. What is the Welsh peanut tube No. W.T.-S01, and how does it compare with the standard 6-volt tubest Refer me to back issues if necessary for the diagrams as I have all the back numbers. — A. E. McCullogh, 649 East Buchtel avenue, Akron. Ohio. 1. *While this circuit can be used with honeycomb coils, you will not have very great success with it. The feature of the entire set is the fact that the coil, which is a spider-web type, and the coupling are fixed, the tuning being accomplished by means of taps and condensers. We refer you to page 23 of Radio World for Jan- uary 13, 1923, where you will find the hook- up with all constants, as well as a detailed description of how to wind and tap the coil, in answer to a query from Mr. C W. Stewart 2. The correct spelling of the word is "Reinartz." It is the name of the man who discovered the circuit 3. This is a new, small tube, manufac- tured by W. Guild, 68 Glen Ridge avenue, Glen Ridge, N. J. We do not discuss in this department the relative merits of com- petitive types of apparatus such as this. We suggest that you write to the address given for descriptive literature. / have seen advertised a new tube made by the General Electric Company, called the U. V. 201 A. Kindly let me have all the data on this tube. — A. J. Patterson, West- Port, N. J. We refer you to the article on the sub- ject in this issue of Radio World. * * * / have constructed the set described by Mr. J. Rum ford in Radio World for March 3, 1923, and have been unsuccessful in getting any results out of it except a loud, bussing sound. What may be my trouble f —W. A. Cole, 56 Beaver street, New York City. You mention in your letter the fact that you have your honeycomb coils mounted one above the other. This is wrong. They should be mounted in a vertical position at right angles to one another, exactly as shown in the diagram, so that they will form two sides of a rectangle. They should be mounted about three inches apart The wiring for this set should be as short as possible. Do not wire with straight-line bus-bar wire, but use heavy cord wire that can be run in straight "bee" lines. Use correct capacities as marked in the draw- ing, and do not have the variometer in inductive relation to either of the coils. By that we mean do not mount it near them. A grid leak is not necessary with this set and should not be used. The honeycomb coils should not be mounted in such a fashion as to be movable, but made stationary. Make sure that you have a hard tube, as a detector will not function well with this set If it does function at all it will give little better results than you have already obtained. * * * In relation to circuit No. 2, published on page 4 of Radio World for February 3, 1923, will you kindly advise me how this could be hooked up as a single-circuit regenerative set, what apparatus is used and where placed T— Roy McShaffrey, Star The- ater, Manes sen, Pa. It is not advisable, but it can be done in the following manner if you wish, although the results you will get are questionable: Instead of using the loop, hook the leads from the single-circuit coupler to the leads where the loop is now connected with the variable condenser across the leads. Make the antenna lead tap off so as to go to the grid of the first tube, and the other end of the circuit (the one going to the ground) go to the other lead, where the other side of the loop is connected. Then connect the rotor of the coupler in the plate circuit of the third tube (detector) in the same manner as you would connect it were you using a single-circuit regenerative. This is for your information, and, although it might prove to be an interesting experiment, it is doubtful if it would work. The circuit as it stands is capable of oscillating, due to the back-coupling of the circuit through the tubes and transformers. We advise first hooking up the circuit as it stands. If you care to use a regular variocoupler, with antenna and ground, connect the rotor in place of the loop the same as in a regular circuit * • * 1. In the article appearing on page 11 of Radio World for March 3, 1923, Mr. Rum- ford states that it is not advisable to use an outdoor aerial. But as I have a 60-foot outdoor aerial, will it be possible for me to use iff 2. Kindly advise me if I could construct the two honeycomb coils— namely, L. 1500 and 1250— and how to do it.— P. G. Pedicord, Premier Service Co., 120 No. Market street, Wichita, Kan. 1. The reason for this statement is that the set is so super-sensitive that a great deal of outside interference, such as static and re-radiated signals, would make recep- tion extremely hard. The loop is the ideal medium for this set and should be used, although, as ah experiment you might try the antenna and ground, connecting them in the place marked for them. 2. It is so much easier and cheaper to buy these coils that it would not pay you to make them. They have 1250 and 1500 turns apiece, and it would probably cost you more to construct them yourself than the market price. You must also take into con- sideration that the manufactured article is usually perfect, whereas you would have to take a chance on your construction being O. K. The building of small coils which do not require over 75 or 100 turns is a different matter. Details for the construc- tion of such coils are given in this issue by Ortherus Gordon under the heading "How to Make the Honeycombs for Your Flewelling." * * * Is there any postage or tost imposed on radio apparatus coming from Great Britain f —John Docherty, 179 East 110th street, New York City. There is the regular duty, plus a special tax on electrical goods manufactured out- side the United States, which b imposed on all goods of this sort Apply to the Collector of the Port of New York, Custom House, New York Gty, for values and assessments on these as they change with the value of import and salable value of goods. Radio to Prevent Mine Disasters HERBERT E. METCALF, a radio engi- neer, has predicted that disasters in mines may be averted, mining camps put in touch with the outside world of business and entertainment and the expense of com- munication lessened by the installation of radio telephony. Mr. Metcalf gives an affirmative answer to the question, "Can radio be used underground? Mr. Metcalf is quoted as saying: "Radio waves do penetrate the ground and do travel through the earth much the same way as they travel above the ground. There are, however, certain limitations which tend to absorb the power of the transmitting set when sending underground ; but due to the increase in efficiency and sensitiveness of receiving sets, it may be stated with authority mat no difficulties are encountered in sending messages from the surface to the bottom of the deepest mine unless perhaps the receiving set in the mine is surrounded by a high metallic con- tent iron ore. The above remarks apply principally to receiving below from a send- ing set above. The reverse — sending from below to be received above — is a little more difficult especially in metallic ore mines." Secretary Hoover Will Appeal Radio License Case AN appeal will be taken by Secretary of Commerce Hoover from the recent de- cision of the District of Columbia Supreme Court ordering Mr. Hoover to issue a radio license to the Intercity Radio Company of New York, according to an announcement by the Department of Commerce. Secretary Hoover, empowered by legislation to regu- late r,adio communication, refused a license to the Intercity Company on the ground that it interfered with naval and other radio communication around New York City. The company took the matter to the court and obtained a favorable decision. Colby Academy Radio Club EDITOR, Radio World: The officers of the Colby Academy Radio Club are as follows: Thomas O. Parker, Ficuhr Advisor; Vermal C. Buchlin, President; Raymond Knight Chief Operator; R. W. Ringrose, Secretary. Membership in the club is open to the whole student body. The apparatus is bought by the Science Division. Radio con- certs are given twice a week to the students in the chapel. The radio room is open daily from 5 to 6 p. m. Yours truly. Visual C Buchlin, March 15, 1923. New London, N. H. President Sewickley, Pa., "Y" Radio Club EDITOR, Radio World: The names of the officers of the Sewickley "Y" Radio Club are: Instructor, W. S. Fraser; Presi- dent, John Kinsvatter; Secretary, Robert Ritchey; Property Man, Edwin Hingst Yours truly, Sewickley, Pa. Robert Ritchxy, March 20, 1923. Secretary. Growing Into Big Figures SECRETARY HOOVER, of the Depart- ment of Commerce, recently estimated that there were at present somewhere be- tween 1,500,000 and 2,500,000 radio-receiv- ing stations now in use in the United States. Digitized by Google

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RADIO WORLD 19 Latest Radio Patents Radio Receiving Apparatus No. M«,M*i Patented Feb, B, in. Patentee! Lloyd Eapensehlod, HoUU, N. Y. THIS invention relates generally to systems for transmitting energy, and particularly to the protection of such systems against disturbance. Its object b to provide a method of, and apparatus for, eliminating or minimizing the effects of disturbances in such systems, whether in power circuits or signaling systems, and in either wire or wireless systems of com- munication. The invention finds one very important application in the radio trans- mission of intelligence as a protection Diagram of Receiving Circuit aa Lloyd Eapanaebled and espial lowing text* m the against the electrical disturbances commonly known as "static"; and the invention will be here described as applied to such a system, but, as will clearly appear herein- after, the invention is of much broader applicability. In radio signaling systems the _ usual antenna is sharply tuned to increase its re- sponsiveness to waves of the particular fre- quency to be received and to reduce the liability of interference from signals of other frequencies. The effect of static dis- turbances upon an antenna thus sharply tuned seems to be analogous to that of a blow upon a tuning fork; that is, the energy of the impact is converted largely into oscillations of the frequency to which the device is tuned. In a wireless receiving system this means that the disturbance will appear in the receiver to the confusion of the signals it is desired to observe. In other words, the receiving systems, instead of excluding the static disturbances by reason of existing differences between them and the signaling impulses, or instead of accentuating or producing differences be- tween them, tends to effectually extinguish the differences that do exist, so that the dis- turbance is in a sense manufactured by the system for its own receiver. Like phenomena may occur in almost any energy transmission system where some or all of the transmitting medium has a natural period or is capable of responding sym- pathetically to foreign disturbances. This invention proposes to avoid such disturbances by changing or diverting the disturbing energy into a plurality of fre- quencies other than that of the energy to be transmitted or into a band of frequencies of considerable extent so that, even though the frequency being transmitted falls within its scope, only a small proportion of the disturbance reaches the translating or in- dicating devices of the system. Variable Inductance No. M«MMi Patented Fab. 2*, ISO. Patent**: Marvin C M. Lane. RooeUe Park, N. J. THE special objects of the present inven- tion are to combine in a simple, compact structure all the functions of a variometer, variocoupler and variable inductance, which will be capable of a fine degree of tuning throughout a comparatively wide range, in- cluding the longer as well as the usual short wave lengths. In the accomplishment of telegraphy or telephony, or for signaling in general, or for any other purpose. My invention resides in apparatus of the character referred to comprising a closed circuit whose distributed capacity and in- ductance are preferably very small or sub- stantially nil— the closed circuit — and par- ticularly the inductance or coil therein, operating as a capacity area connected through tuning apparatus, as variable in- mnatic drawing ffluatroting tb* now Vi coupler aa patented by Mr. C M. Lane. -these objects the inventor uses a single tubular core upon which there is placed a bank-wound coil provided with taps and as a continuation of that a straight wound coil within which is journaled a rotor so posi- tioned that it can be turned to carry its windings partly beneath the bank-wound ■coiL Radio Method and Apparatus No. M47,Mti Patented Fab. Z7, IMS. Patentees Frederick A. Koletar, Washington, D. C MY invention relates to apparatus for transmitting or receiving electro- radiant energy or electro-magnetic waves •for the transmission of intelligence, as for ductance, with the earth or any counterpoise capacity. Receiving apparatus embodying my in- vention is an absolute direction finder or a true radio compass whereby the location of a source of radiant energy may be deter- mined. Such receiving apparatus serves also as an excellent interference preventer; that is, for permitting reception of signals from a desired station to the exclusion of signals from other stations differently located with respect to the receiving station, and to the exclusion of atmospheric or natural electrical effects. Transmitting apparatus embodying my invention has the property of transmit- ting energy of greater intensity. Generator and the Generation of Multiple Frequencies No. L_ 44f,7SZl Patented Feb. 17, MB. Pa* Barton W. KamkdL New York, N. Y. THIS invention relates to a method and means for the generation of multiple frequencies, and has for an object to pro- vide a means for producing currents of a frequency or frequencies higher than a given basic frequency. The higher fre- quency currents may be used for any suit- able purpose, such as sources of carrier waves for multiplex signaling. The higher frequency currents are obtained by distorting the wave form of the fundamental frequency and by selecting the overtones or multiple frequencies present in the distorted wave. The distortion may be effected by means of an electric discharge device, which has the following characteristics that give rise to a distortion: First, equal increments in MilHr. I-MIU"! -qut»N \ Mr. B. W. Kendall's method of pie frequency for the transmission of the voltage applied to the device do not produce proportional changes in its output current This gives rise to a distortion, as the input voltage is not faithfully repro- duced in the output circuit This character- istic belongs to all audions which have not been provided with special means to change this characteristic Secondly, a further and greater distortion is obtained, according to the present invention, by considerably over- loading the audion. This is done by apply- ing to its input terminals an alternating potential such that the maximum value carries the operation of the tube beyond that portion of its characteristic which is substantially linear, thus substantially dis- torting the wave form of the applied alternating potential as repeated by the tube. This applied alternating potential may be such that the maximum positive value will exceed that necessary to cause the tube to become saturated and the maximum negative value will exceed that negative value re- quired to reduce the output current sub- stantially to zero, or one of these conditions may exist alone to the substantial exclusion of the other. The number of electrons which can be given off by a thermionic cathode at a certain temperature has a limit- ing or saturation value, and the correspond- ing point on the characteristic curve of the electron discharge device may be termed the saturation point of the cathode for that temperature. Accordingly the cathode will limit the space current which can flow in the thermionic device, and variations in the internal impedance in the circuit of the space current are not followed by proportionate changes in the value of space current Thus the wave form of the output current will be considerably distorted. Thirdly, in some cases a further distortion may be obtained in the suppression of the alternate half waves by passing the distorted wave through a unilaterally conducting device, such as a thermionic rectifier. A particular electric discharge device may have one, two or even three of the distorting characteristics just described. Digitized by Google

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20 RADIO WORLD New Records of The DX Nite Owls Paste These in Your Hat Fran W. H. Hon, Rout* t, Pboanfat, Arinu I AM enclosing herewith a list of stations that I have heard, and which I know will be of interest to the DX Nite Owls. The greatest distance covered is 2,200 miles, from WGY, Schenectady, N. Y. Early Sunday morning, March 4, this station was coming QSA on one stage of audio, and on two stages they nearly knocked the phones off my head. WDAP, Chicago, was also very strong at the same time. The set is home-made, being a two-circuit detector with two stages of audio frequency and one stage of radio frequency, which is tuned with an ordinary variometer. A 400- ohm potentiometer is used; 27 volts on the detector, 110 volts on the plates of the amplifiers, and 4l/i volts on the grids of the audio amplifiers. Aerial is inverted L type, 65 feet long and 25 feet high. The following stations have been heard here: Call Location Distance AGI San Francisco, Cal. 650 DN4 Denver, Colo. 600 KDN San Francisco, Cal. 650 KDPT San Diego, Cal. 300 KDYL Salt Lake, Utah 500 KDYM San Diego, Cal. 300 KDYS Great Falls, Mont. 1,025 KDYW Phoenix, Ariz. 8 KFAB Portland, Ore. 1,025 KFAD Phoenix, Ariz. 8 KFAF Denver, Colo. 600 KFBK Sacramento, Cal. 675 KFCB Phoenix, Ariz. 8 KFCL Los Angeles, Cal. 350 KFDB San Francisco, Cal. 650 KFDL Denver, Colo. 600 KFGH Stanford University, Cal. 625 . KFHJ Santa Barbara, Cal. 450 KFI Los Angeles, Cal. 350 KFV Yakima, Wash. 1,050 KGG Portland, Ore. 1,025 KGO Pasadena, Cal. 350 KGW Portland, Ore. 1,025 KHJ Los Angeles, Cal. 350 KJS Los Angeles, Cal. 350 KLP Los Altos, Cal. 625 KLS Oakland, Cal. 650 KLX Oakland, Cal. 650 KLZ Denver, Colo. 600 KM J Fresno, Cal. 500 KNJ Roswell, N. M. 425 KOB State College, N. M. 300 KOG Los Angeles, Cal. 350 KPO San Francisco, Cal. 650 KQW San Jose, Cal. 625 KRE Berkeley, Cal. 650 KSD St. Louis, Mo. 1,300 KUO San Francisco, Cal. 650 KUS Los Angeles, Cal. 350 KUY El Monte, Cal. 325 KWG Stockton, Cal. 585 KWH Los Angeles, Cal. 350 KYJ Los Angeles, Cal. 350 KYW Chicago, 111. 1,600 KZN Salt Lake, Utah 500 WAAP Wichita, Kan. 900 WBAP Fort Worth, Texas 825 WBL Anthony, Kan. 800 WDAF Kansas City, Mo. 1,050 WDAH El Paso, Texas 300 WDAP Chicago, 111. 1,600 WDAV Muskogee, Okla. 925 WFAA Dallas, Texas 850 WGY Schenectady, N. Y. 2,200 WHB Kansas City, Mo. 1,050 WKY Oklahoma City, Okla. 825 WMAB Oklahoma City, Okla. 825 WOC Davenport, la. 1,300 WOAI San Antonio, Texas 825 WPA Fort Worth, Texas 825 WWJ Detroit, Mich. 1,800 9ZAF Denver, Colo. 600 THE Editor of RADIO WORLD vf pfasMd to rocfltw flkotch#s of hook *m cararuUy fc> Mack kk ir h paacil from tha -DX Nit* Owk" *fca i la record* wtta a vfaw ta pnhllanlaa t) H Of Write on mm wUm at tha ma Thm lattera and. aaak-aao Habad la tha RADIO WORLD. Send a Stamp for This Hook-Up Ban E. Nobla, 15*. Pacific Mo. 1AM a regular reader of your fine maga- zine, and I have got some helpful hints from every issue. I am submitting my record since January 15, 1923. I did not think so much of it until I noticed so many others, and I believe I have something to be proud of. I am using a one-stage WD-11 tube set I made myself, vario-coupler, 23- plate condenser with vernier adjustment in series with aerial, Jenkink rheostat on detector tube and Freshman grid leak. The number of stations I have heard is 115, covering 37 states on the Pacific Coast and Atlantic Coast; also five provinces in Canada; Gulf Coast and San Antonio, on the border. My greatest distances are: WLAF, Fairbanks, Alaska; PWX, Havana, Cuba; KFD, Los Angeles, Cal.; KGW, Portland, Ore.; KDYL, Salt Lake City, Utah; KDYS, Great Falls, Mont.; KWJ, Roswell, New Mexico; WOAI, San Antonio, Texas; WOR, Newark, N. J.; WHAZ, Troy, N. Y.; CKCK, Regina, Canada; CFCA, Toronto, Canada; CKAC, Montreal, Canada; CFCB, Vancouver, B. C; CJCG, Winnipeg, Man.; WNAQ, Charleston, S. C; WFAH, Port Arthur, Texas; WAAB, New Orleans. La.; WKAH, Palm Beach, Fla.; WJAP, Duluth, Minn.; KFAF, Denver, Colo.; WBZ, Springfield, Mass.; WDAL, Jacksonville, Fla. I have heard a few distant stations while our local station, KSD, twenty-five miles away, is transmitting. I have no trouble at all tuning them out for the eastern stations, and on one occasion I had PWX, Havana, Cuba, only eight degrees from the post, and could not hear the post. Any one wanting this hook-up of my set may have same by sending a stamped envelope. I did not think anything of my log until I noticed what others were doing. DX News From New Bruns- wick, Canada From NmI Coleman, St, John, N. B., Canada. AFTER having seen many records in Radio World I wish to submit my list of stations. My set consists of a vario- coupler, a variable condenser and two stages of amplification. I have an aerial 90 feet long with a lead-in of 40 feet, single wire. My stations are: WGY, WJZ, WOR, WNAC. WGI. WIP, WOO. WWJ, WEAF, WSB, WMAQ, WMAK, WHAZ, WHAS. WDAS, WCAE, WHA, WHK, WFI, WNAT, CHCX, PWX. WQAA, WEAA, WCAU, CKAC, CFCF, WHAM, WBAY, WGR, WOC, KOP, KDKA, KSD, WBZ, WBT, WBAP, WDAP. and about twenty more stations. I have only had my set for five months. A New Sailor Nite Owl Fran R. W. HiMfea, U. S. Naval Traariaj Station, Newport, R. L I HAVE something for the good of the order. I have no hook-up of my own, but an $18 regenerative set, using WD-11 tube with adapter and lighting circuit for aerial. Here is my record night for you to slant at: WEAN, WJAX, WGY, WBZ, WJZ, WEAF, WGAS, WBAK, WOC How is that for the electric-light aerial? Chicago and Davenport clear as a belL Can Equal the Record From Rotor H. Bui-riD, CampoHo. Mm AFTER seeing your DX night owl de- partment I think that I can equal the record of anyone who has the kind of set that I have. My set is of the single circuit regenerative type. My aerial is one hundred and fifty feet long. The ground is attached to a water pipe. The set I have is a one- tube WD-11 with 43 volts on the phut. These are a few of the stations that I hear regularly: PWX, WSB, WHAS, WGY, WGI, WNAQ WLW, CFCF, CFCA, KDKA, WOC, KYW, WEAC, WOO. WOR, WJZ, WIP, WBZ, WHAM. WEAF, WRW, WFI, NAA, etc. Doing Away with Taps Fran J. White, Brooklyn, N. V. SEVERAL days ago the windings on the rotor of my vario-coupler came loose, and I began experimenting with my set, and at last hit on a substitute for my vario- coupler. By setting the two coils of the stator in series and disconnecting the rotor so that it acted like the rotor of a vario- coupler I had a good substitute. By placing the aerial and ground on the stator and the usual secondary connections on the rotor I obtained good results. I received KDKA, WGY, WJZ, WOR, WEAF, WAAM. WBAN and WQA in one hoar on list Sunday night. I had a regenerative receiver employing one vario-coupler, one variometer and one vario-condenser (21-plate), using a WD-11- Of course the results were not so loud, but it is a good substitute for the amateur who wishes to do away with taps. Good Record for Single Tube From Perldna Bomeran, 8S7 Poplar An, Fraann, CaL I HAVE written before, but if this is printed I will promise to forever hold my peace. I wish to present a list of DX stations which I heard on a recent night, using a single UV-200 detector tube only: PWX, Havana, 2,425 miles; WCAE Pitts- burgh, 2,150; WSB, Atlanta. 2,025; WGM. Atlanta, 2,025; WWJ, Detroit, 2,000; KYW, Chicago, 1775; KSD, St Louis, 1,625; WOC, Davenport, 1,600; WHB. Kansas City, 1,400; WDAF, Kansas Gty, 1,400; WBAP, Fort Worth, 1,300; CFCN, Calgary, 1,100. How is that for a nice little record, Mr. Editor? No doubt it has been beaten by fans using two, three or more tubes. But who has done better on a single tube? As I have not as yet seen any that beats this I claim the record for single-tube, tingle- night reception. If you have beaten this. Mr. Fan, let's hear from you. {Continued on page 26) Digitized by Google

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RADIO WORLD 21 Electric Ferry "Poughkeepsie" Is Revolutionary Type of Craft THE most . unique boat in the world is now plying the Hudson River between Poughkeepsie and Highland. She is the ferry boat "Poughkeepsie," and she is not only electrically propelled, but she is con- trolled like an automobile, she has a lower operating cost that any other vessel of her size and power afloat, and she is also speci- ally designed for breaking through ice. Be- cause of this unusual combination of novel features, she has probably attracted more attention than any vessel since the "Mon- itor." The United States Navy was the first to appreciate the advantages of electricity for ship propulsion and it took a long step in advance of other naval powers by equipping all of our recent battleships with electrical propelling machinery. Electric drive is also in successful use on several pleasure yachts and on certain other craft of a more or less understood. This facility of control is of great importance to a vessel that must con- stantly enter slips and thread its way through crowded traffic. No less important, however, is the "Poughkeepsie" high fuel economy. Be- cause her engines are of the internal com- bustion type, they can develop their full power on less than one-third the amount of fuel required by the most efficient type of steam engine. This means that her operating cost is extremely low and makes this type of drive very desirable in all classes of ves- sels in which it can be used. A feature of the "Poughkeepsie" that will be especially appreciated by motorists cross- ing the river next summer is that because of the compactness of her Diesel-electric machinery it can all be contained within the hull with no superstructure on the main deck. Hence this deck is perfectly clear and Electric Ferry Boat "Poufhkeepeie" la Controlled from the Pilot Houw experimental character but the "Poughkeep- sie" is one of the very first commercial ves- sels to be electrically operated. She is, there- fore, a pioneer ; and in the opinion of many marine engineers she marks the beginning of the electrification of our river and har- bor vessels, and perhaps our merchant ma- rine as well. An electrically-operated ship differs from an electrically-operated locomotive in that she cannot get her electric power by wire or third rail, but must generate it herself. The "Poughkeepsie's" generating plant consists of two Winton engines of the so-called Diesel type; that is to say, they resemble automobile engines but use heavy oil instead of gasoline for fuel. Each engine is rated at 125 horsepower and drives a 90-kilowatt Westinghouse electric generator. These gen- erating units operate continuously at con- stant speed and in one direction only when the boat is in use. They do not control the speed or movement of the boat, but merely furnish electricity for two 100-horsepower Westinghouse motors which are geared to the propellers. The control of the propeller motors is centered in a small handle mounted behind the wheel in each pilot house. By moving this handle, the pilot himself starts the pro- pellers, changes their speed, stops or re- verses them. He therefore operates the boat just as a chauffeur does an automobile, without losing time signalling to the engi- neer or running the possibiVry of being mis- can accommodate four lines of automobiles, instead of the usual two lines only. In fact, though the "Poughkeepsie" is barely half the size of a Staten Island ferry boat, she can actually carry more cars. This Urge car- capacity is expected to eliminate waiting at Poughkeepsie and Highland during the com- ing touring season. The "Poughkeepsie" has to be an ice- breaker if she is to operate continuously during the winter, since the ice is often over two feet thick at this point. To look at her, she seems broad, shoal, and of very light draught. This is not the case, however, for under her visible hull is a second one, known as the "hullfin," which carries the propellers. When the "Poughkeepsie" runs into ice, she does not wedge mto it as a boat with an ordinary keel would do, but her broad end rides over it, crushes it, and then pushes it aside. Her propellers, being be- neath the main hull on the bullfin, are al- ways deep in the water and are uninjured by the ice. Victor Erects New Building The new building recently erected by the Victor Talking Machine Company at Camden, N. J., will be used for the manu- facture of phonograph records and not for making radio equipment. Vacuum tubes are now used by the Victor company in record- ing the voice. The Power Amplifier for your Magnavox Radio THE Magnavox, in reproducing with extreme sensitiveness every signal supplied to it from the receiver, must necessarily re- produce any extraneous sounds which may originate in the receiver or power amplifier itself. Therefore, to obtain all the won- derful results of your Mafnarox Reproducer, use it with the Mag- navox Power Amplifier. R-2 Magnavox Radio with 18-inch horn T" 1 r 'HIS instru- ment is in- tended for those who wish the ut- most in ampli- fying power : for large audi- ences, dance halls, etc., but requires only .6 of an am- pere for the field. R-3 Magnavox Radio with 14-inch horn SAME in principle and construc- tion throughout as Type R-2. Is ideal for use in homes, offices, amateur stations, etc. Requires one ampere field cur- rent from your filament battery. Magnavox Power Amplifier— Model C CAN be used with any "B" Bat- tery voltage which the power tube may require for best ampli- fication. 2-Stage and 3-Stafe The facilities and experience back of each piece of equipment bearing the Magnavox trade mark are unrivalled anywhere in the world. Magnavox products may be had of good dealers everywhere. Write to ut for illustrated booklet The Magnavox Company Oakland. California New Yorlc Office : 370 Seventh Ave. Digitized by Google

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22 RADIO WORLD Advertising Rates : Display, $5.00 per inch, $150.00 per page. » Radio Merchandising Classified Quick-Action Advertising, 5 cents per word. Telephone Bryant 4796 New Radio Firms {The new Arms and corporations men- tioned in these columns can be reached directly or by communicating with the attorneys, whose addresses are given when ever possible.) De Forest Phono Film Corp., Dover, Del., pat- ents, $4,750X100. (U. S. Corporation Co.) . Marvel Electric Supply Co., New York City, $5,000; D. E. and M. Greenbaum, A. L. Popper. (Attorney, M. Popper, 99 Nassau St.) Wallace Electric Co., Rochester, N. Y., to issue 500 shares preferred stock, $100 each; 300 common, no par value. Radio Construction Co., Wilmington, Del., radio, $750,000. (Corporation Trust Co. of America.) Tristan Sales Corp., New York City, make wire- less apparatus, $100,000; C. M. Jost, C. W. Hanes, A. Klein. (Attorney, L Cohn, 1540 Broadway.) Woodlawn Electrical Appliance Co., Wilmington, Del., $100,000. (American Guaranty & Trust Co.) Backus, Minn., Telephone Sub- scribers Get Free Radio Concerts RADIO reception has been greatly sim- . plified in Backus, Minn. If the Backus resident is a telephone subscriber he simply takes his telephone receiver from the hook and music, drama, sermon or lecture pour out. He has no need to worry about run- down batteries, weak tubes, the intricacies of hook-up or the length or height of his antenna. Miss Anna Ozier, chief operator for the Backus Telephone Company, re- cently wrote WGY, the radio broadcasting station of the General Electric Company, Schenectady, N. Y., as follows: "We have a receiving station here and by putting the horn close to the transmitter and connecting up the farm lines, I have a system now by which the subscribers on our farm lines who have never had an op- portunity of getting concerts direct from the air have passed many of these winter evenings enjoying themselves by turn and turn about at the telephone. "I know of several cases where three or four people have listened in on the same receiver at once. In one case I was sur- prised by being recompensed by a lady who was so much pleased by the concert and the part she though I took in it, that she brought me a dozen eggs. As she said, it was her way of saying 'thank you.' " Radio Stocks {Quotations as of March 14, 1923, furnished by Frank T. Stanton & Co., 35 Broad Street, New York, Specialists in Wireless Securities.) Stock Bid Asked American Marconi, Stamped. . 5* IS* American Marconi, Unstamped. 5* 7* American Tel. & Tel I25J4 125}4 Canadian Marconi 2}i 3 De Forest Radio 7 10 Dubilier Condenser 9 9% English Marconi com 11 15 English Marconi pfd 11# 15*S Federal Tel. Cal 5# 6 General Electric 188# 189 Hennessy Radio Pub 9 11 Mackay Co. com Ill 115 Manhattan Elec. Supply 55 57 Marconi Int. Marine 7 10 Radio Corporation com 4% 4% Radio Corporation pfd 33/£ 3}4 Spanish Marconi 1 3 Western Union 115 116 Westinghouse E. & M 65 6Syi 'Cents per share. Naval Communications Service Has a Big Year GOVERNMENT messages totalling 15,763,308 words were handled by the Naval Communications Service during 1922, according to a statement made public last week by Acting Secretary Roosevelt. Of this total, 10,000,000 were for the Navy, the remainder being official business for the various Government departments. The House of Representatives is at the bottom of the list with 505 words, with the White House next to last with 1,258. Coming Events PERMANENT RADIO FAIR FOR BUYERS, Hotel Imperial, New York City. Open from September, 1922, to May, 1923. ANNUAL HOME AND CITY BEAUTIFUL EXPOSITION, featuring; radio exhibits. Atlantic City, N. J., June 16 to September 8, 1923. RADIO AND ELECTRICAL EXPOSITION, including* amateur home-made set contest, San Francisco, Cal., April 3 to 8, inclusive. Crosley Celebrates Second Anniversary THE Crosley Manufacturing Company, Cincinnati, Ohio, home of the broad- casting station WLW, celebrated its second anniversary last week. This celebration, however, applied to the radio division. Two years ago, on Washington's Birthday, Powel Crosley 3d wanted his dad, Powel Crosley, Jr., president of the company, to purchase a radio-receiving set for him. His classmates had one, and, boy-like, he, too, wanted one. When Mr. Crosley went to the Precision Equipment Company to buy the radio set he found the prices were very high. With the idea in mind tha^ there must be thou- sands who would want a set he called in an engineer, and together they designed a cheap radio set The first of these receivers was ready March 21, 1921. The Crosley socket with its design for mounting upon a panel, the variable condenser with its book-type action, and other distinctive apparatus now well known in the Crosley line, came as a result of a little boy want- ing a radio set. It is interesting to note that, within two years from the time Powel Crosley, Jr., went to the Precision Equipment Company to inquire the cost of a radio-receiving set, he purchased the company. The Crosley Manufacturing Company has one large factory, where an extensive line of radio apparatus is manufactured; another makes the cabinets, while a third establishment is the printing plant. A little informative newspaper is issued, called the "Crosley Radio Weekly," which gives programs of the Crosley station. The Delta Dry-Cell Tube The Delta Midget Tube Company, 241 Market street, Newark, N. T., have brought out a new dry-cell tube taking three volts and using an amperage of .15. It is said to be equal to doing the work of the W-D 11 tube. This firm also manufactures sockets and adapters for their tube. The entire line of products, both because of the present shortage of tubes and the inherent quality of the line, is proving very popular. These Cheerful Workers Make "Signal" Radio Equipment A Group of Employees Outside tha Factory at tha Sijnal Else trie Manufacturlns; Cosnpany, ^nosas^e^l^^ ||

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RADIO WORLD 23 Advantages of the Hazeltine Neutrodyne Circuit THE moat remarkable feature of the neutrodyne circuit, invented by Pro- fessor L. A. Hazeltine, of Stevens Institute of Technology, Hoboken, N. J., which was illustrated and briefly described in Radio World for March 10, 1923. is that great distances, hitherto unobtainable, are secured with clear and undistorted reception. The neutrodyne circuit is non-regenerative. Therefore the familiar whistles and squeals which attend the "tuning in" of a regenerative set are entirely absent Experts who have tried the few sets available at this early date report picking up stations clear across the continent ; and, what is most remarkable, the quality of the music and speech is practically like the clear tones received on a short-range crystal detector set To the initiated radio enthusiast the neutrodyne set looks unlike any heretofore constructed. There are no variometers, no variocouplers and no ticklers. Tuning is effected by three variable condensers, two of which are set at the same definite settings for definite wave lengths, and antenna tuning is accomplished entirely by a single dial operating a variable condenser. Other features are the use of new types of jacks for automatic filament control and the devices called "neutroformers," to which the high amplification is due. The invention, from a technical standpoint, comprises means for neutralizing the effect of die inherent capacity between the grid and plate circuits of a vacuum tube, thus enabling any degree of high frequency amplification to be obtained without regeneration or feed back, and without the distortion which attends regeneration. The term "neutrodyne" is used advisedly, '"neutro" meaning equal and "dyne" mean- ing a force. An electrostatic force is applied to the grid of each high frequency amplifier tube, which force is equal and opposed to the effect of the "grid-plate" capacity of the tube. Thus undesired effects of the inherent tube capacity are neutralized or balanced out. In technical circles it is expected that this invention will entirely revolutionize radio-receiver design. One of the pleasing features of the neutro- dyne circuit is its great selectivity. It is possible for the "listener-in" to make a log or station record, in which the settings of the dials are recorded for various stations. Once this log is made any large station in the United States with a transcontinental sending range is picked up by merely setting the dials at these positions. Unless a sending station changes its wave length the record of dial settings is permanent and never varies for that particular installation. The patents of the inventor have been exclusively licensed to a group of manu- facturers united in a trade organization known as the Independent Radio Manufac- turers, Inc., 165 Broadway, New York City. Among this group are three who will manu- facture the Hazeltine apparatus under sub- licenses. They are Freed-Eiseman Radio Corporation, New York City; F. A. D. Andrea, New York City, and the Garod Corporation, Newark, N. J. The anniversary number of Radio World, to be dated March 31, 1923, will contain an extended description, with several illustra- tions, of the Hazeltine neutrodyne circuit Princeton University Radio Club Sets a Mark THE Princeton University Radio Club, Princeton, N. J., has established what is claimed to be a record for the number of messages handled in a month by an amateur station. From the 15th of one month to the 15th of the next the Undergraduate Club passed the 1,000 mark. The record of the club is 1,226 radio messages in a month, and in the four months of the existence of the club the amateurs have handled more than 4,000 messages. The club, which was started last November, has been licensed by the Government to carry on experimental work. It has twenty-five members, seven of whom are licensed operators, and they operate the station on a twenty-four-hour basis. SUNBEAM MOTTO FIRST FOR PRICE, QUALITY, AMD SERVICE II yaan at the mm taet AH atondnrfl mcrelwdiM gnawmleed. Price* gotmg up. Take advantage of pre— a t law rata. On roartntat pratldM you atHtraflUtn, or your wov talk, wo win WW LOUD SPEAKERS 145.55 MMHnx. aw ty*i.*S«.5l SB.S6 Weatara ElMtrl*.... SS.SS SS.St Ansiltea* IS.IS SS.SS DMssrael IS.SS TRANSFORMER* U. V. 7 IS SS.SS U. V. 714 5.45 AajM 4.75 DaytM 4.75 Raataae S.SS _ CONDENSERS, BAKELITE U trittt, R*4t» tow *tt tvtatat fttatlls Mmu ••••■■••••••■«••• ►HOMES BaMvia elT!" t» flats. Vereler «l alata. ... VersJar U. 8. Tail IS slats. Flan eat* 43 plat*. Flan aes* RECEIVING. SETS DoForoot RadttBsaa* Dotootor Sll.ee DtFeraat 3 Stall AawlMar ie.ee Amm 2 Stan Am I ha* 45.00 Oaahaua □ (tatter 45.41 aaakaia I stse AmllOar 75.44 Oaastan 1 Stop Aasliajtr ISS.ee (Oansltte vltk TukM, "B" Battury, "A" " VARIOCOUPLERS SS.SS DortM Faa 47.55 S.SS ISO Desrae •Ilk WaaaS.... S.S5 >••• VARIOMETERS >■** DaytM Faa SS.SC H* *"«r ...... 2.55 *■** Start* BaktIHa JM RHEOSTAT* Oattar-Heauaar Varaltr 51.15 Fatwal, 240 Man 41.15 Ootlar-Heauatr Mm VaraUr .55 Rati* (WaaVatloe, 254 Mau S.44 Safatyitt* .55 "B" Rat., Emraaay. tlVa V., Lara*. 2.44 "8" Bat. E*w*ae>. 45 V. Lara* S.7S OOIL MOUNTINOS t C#H Ds>Fw)t*w*lt IMllOllltM ■•■■MIIMI 4$»JbM S Call r Baralak Mardeak 4444 Aatk POTENTIOMETERS 51.15 S.7S 4.IS 4.S* 5.54 1.44 2.14 MISCELLANEOUS 2" Dial* 5" Dial* 4" Dial* Pint Flrta Jaaka Mael* Mataat Jaaka DeuMs watut B ladles Pwrta, Nlaktl or Rubbtr. • •?» M .00 ,74 I.SS "B" Battary. Atrial, rat.) BATTERIES 54 An*. OS Ana. ■ ie An* 22K V., (anil. .414.44 . ie.se . 15.55 . 1.20 Mia Srlt Laaka. FraMH Pssar Oaadenttrt, All Sim. Wlr* .50. .55. .75, 1.44 1.44 45 .IS SI 10 40 Sunbeam Multlrange Varioconpler, 180 to 8000 Meter*. Oempleto CoU Only S 1*7 or. Baak Womtd, Bilk Wire (Hoak-np Fvrnlataed with CoU) » *S.SS Select your let ana write tit for prion. We'll do tho ret. SUNBEAM ELECTRIC COMPANY 71 THIRD AVE. (Bet. 11th and 12th St*.), NEW YORK "WINDSOR CASTLE" PHONES $5.90 "Windsor Castle" Phones are made in the United States for the Canadian trade. Hence the British flag on the label. Marvelous Soot-Ohm Instrument It ia your opportunity to get into the bis D-X Qua. Toronto, Canada, bear* WEAF, as well aa WOC and other distant stations nightly with these Phones. Look for the full name on the Cap. And be sure you are getting the Special IMPREGNATED BLUE DIAPHRAGM This BLUE DIAPHRAGM is IMPREG- NATED with a Special Chemical for Sta- bility. Insist on it and the name "Wind- sor Castle." Sand us a Money Order and oar Mall De- partment wOI do the net quickly and efficiently. We pay Postage east of Mis- Send for Free Catalogue Dept. 84D. D-X-RADIO CO. 123 Liberty Street New York Ctty SIX REASONS WHY A "Vac-Shield" 1— Non-Magnetic i — Prevents later* stage Coapllng. 5— Stops H.wttng, 4 — Prolongs Life of 8— Tones la DX. 5— Protects Taboo. Attached la a Mlnnte. Order today. Win ik* immediately by mail pottpaAd on receipt of $1.00. ORANGE RESEARCH LAB. 41 Norm 14th Street East Presage, If. J. ise-teee Motor*, _ Host* Can* OaTl— O L He. 45 Hoeoy Oaafe Ml — D L He. 75. S-Way I" 45 Volt »tt V*tt 0 Bettorta* Aaaaa Traaaferner* Oaatlal W.d.-ii " Klaa Vartsaaater Swill Tyat Variatastar .$4.04 1.44 1.10 .75 1.75 .75 MS 4.55 *M I.7S IM WHITE RADIO CO. IS E. 23rd ST. NEW YORK CITY Cash with Order— Wtalaaala, Rami CRYSTAL-TUBE FOR CRYSTAL SETS Now ready for distribution. It flTO* tlatrtr turn and protoota your crystals. 15o (BUvtr). Oui deacrlftlTt circular atnt froo an naalpt at nai addroto. (Discount t* doolora.) VACUUM ELECTRIC WORKS. Toledo, Oil* Digitized by LgOTBIO WORKS.

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24 RADIO WORLD RADIO PANELS Hlfk »»» ••••••••••••••••••••••••• •"»»«'* U"Rts" Muafaetarerr/ wM (la MlMM. Araeta nM PAGKON COMPANY Bex ••• Meneeata *4a*lea, at Lee la. i lh RADIO MAILING LISTS II.4M Rati* ■ I alar a. aeeerlat U. S. h* I par M, i.iu r " i.Jsj in M7 . Mk Sets. BsTTlst 2S.SS* Ml* 4 ■llllll aed •us I7.M IM W. «M« STMCtT MIMH, ILL. ?4tolOACRE .Radio Farms $OYVPer 'Acre OreaMet tend offer of to* day. dirndl adlatnias World's Oraataat RaeSo Stsuea of Ike Basts Oarrerratlan of Araerlea at eflllara Flaw. Barer, (ban at Laat llliaat la !ua tMI and tnak tardea saanoa. Tsaea fartUa (am Plata. •* ta It* foot abort aoa loroL par- fart far araskana. frail and raeaublae. Only ana and a asartai raUae frara i •apart batHsg. Bathing, tsalag. Da raraatasr kaatalaw aaaap slats. Mow arete rdaweay n rasing property dbtat ta 5»tb Street. Itew Tort, Baslast at oaar teraas. Tttlae gnarantaed. Write for Buna rana rates. O. L. Schwencke Land Co. 771 BROADWAY NEW YORK Ettablithed 25 peart. Flewelling Circuit No ground, no aerial. Portable; can be carried in your car, train or camp. Will get long alii tan ce on a loop. Simple to operate; can be worked witb W. D. 11 Tube. We cell the complete part* to make up this wonderful set fer $2025. Includes the following: 1 Spec Bali el. VariocoupUr fZJt 1 Mas fineat Vernlsr condenser 4JS 1 Socket (genuine ccaadeneite) M 1 Rheoatat (the keat obtainable) IM 3 .m Condensers (mica Dubffiers) . . . 2JS 1 Grid Leak (cartridge type) and bolder M I Freshman Var. Leak and Condenser M 1 BakeUte Dial for VariocoupUr JS 1 Inductance Switck M 5 Lengths Buaa Wire M Z Lengths Spaghetti Ji 8 Binding- Posts -4t 1 Genuine BakeUte Panel. 7"xlS" US Finest make 7x11 Cabinet S.7S WE SELL: 45 V. "B" Batterlee (each) fLM « V. N Amp. Marko's Battery t.Sa U. V. m Tuboa J.as U. V. 2*1 Tubes S.5t U. V. 2S1A Tubea TJS Nathaniel Baldwin Type C, Double Phones t-St Nathaniel Baldwin Type C, Single Phones AM Brandos (Superior) Phones SJS All order* mutt be accompanied- with a money order, pottage included. GRAND RADIO CO. -4 Are. (near fttb St) YORK CITY RADIO WORLD imnpHOW. BBTAMT 4Ttl PUBLISXSJD nTBRT wBDPfaBDAT (Dated SATURDAY Of BA1CR WRaTK) from prjBucAnoM omci, 14tt BROADWAT. traW TOBK, N. T. BT HBWNBBajT BADIO PUBUOATIOIIB BOLAND BURKS HBNNBMY. Pruld.nl and Editor M B. HKNNB89T. Vloa-Prorsdent r&KD a CLARK. Secretary and Manager 1493 BBOADWAT. NIW TOBK. N. T. Boben L. Deughartv Stepboo L. Calei SUBSCRIPTION RATES •It a aspy. tt.tt a roar. It.ll far (LSI fer Sana ■astaa. Add 11.11 a year extra for foreign poetess. Canada 51 rente. Reeatpt re nee loaeerleara at too Brat oesy of RADIO WORLD nailed ta trans after readies la their order, la asteraaaS aaraewlatltataal af rhatr ADVERTISING RATES On. paga: One Urea— lltt.lt. Half Quarter. Third and Two-thirds proparuonata ratea. Ono inch, ona Urea— tS.lt. Par state tt.4t. On four euuaotallTo laouaa. 11% dlaoount. On thlrtaen una i oat I to laaoaa, 15% Corer and profarred-pooluoa ralaa tai oo application. Ttrma: tt dan net. i* It dan. CLASSIFIED ADVERTISEMENTS Fire rente per word. Minimum, It Discount of It* on 4 eonaooutlTa laaure — 19% on thlrtaen cooeacuura laauea. Cash with ardor. at the Past the set of 1-sUae aaattar. Itareh It. Ittl. at New Talk. Mow Terk. i. lira. IMPORTANT NOTICE While 0T0T7 poaatblo ear* Is tskao ta stats aorrooUj reattan of feet and eplnlao la tearenaal and general wrlUnra rerarlni tha radio flald. and erery line printed la tone orer with a aartajnloaa regard far tb* fasts, tb* publisher dlaolstsat aw raeponalbUlty far ateteraenta resardiu gaiafltoa of patents. priority of elalare. the proper worktaf eut of taoaaterJ aroblaaa. as ether reattan that raw be printed la goad faith and en IreTarresuas furnished by those auppaaad te ho truatwerthy. Tlds otetaaaaat la resda Is road faith aad ta en* time and oaauoiatsj la mattara eear wrseh the publlsbsr re rant paastbly sera aentreL Beacon Fires, Radio, and Cable Will Aid Arctic Explorer ROALD AMUNDSEN, the famous arctic explorer, plans to hop off in an airplane from Wainwright, Alaska, next June and fly over the North Pole and land at Spits- bergen, Norway — if he's lucky. An elaborate system of communication will be established to report the time Amundsen starts his flight. Wainwright is 400 miles from the nearest radio station, at Noorvik, on the Kobuk River, Alaska. The Chamber of Commerce at Nome, Alaska, has planned a chain of signal fires made of drift wood and coal, and each tended by two Eskimos. These bonfires will be built 15 miles apart. When Amundsen starts the first fire will be lit, and when its smoke is seen the natives will light the second fire, and so on down the line. The news of the start thus received at Noorvik will be broadcast by radio, picked up by other radio stations and relayed by telegraph and cable to Spitzbergen. Here will be in waiting a number of fast scout planes, ready to rush to Amundsen's assist- ance if he gets into trouble toward the end of his flight. Renews Subscription to the "Best Radio Paper" Editor RADIO WORLD: I am renewing my subscription to RADIO WORLD as it is the best radio paper in my opinion and I have tried them all. Enclosed please find check for six dollars for one yearly renewal begin- ning with date stated on bill. Yours truly, ISO W. 86th St. M. J. FOX, JR. New York. March 10, 1923. PATENTS D. a and ate aad. OaB ar FBCf A0VIOK, ▼aradaroUt ftll. Detectors ^niplifiers GUARANTEED REPAIRS Broken and Hsu aad Oat VACUUM TUBES W.D.-11 not accepted for repair Your oaalar ahesld karer. oat If ha seas art. aaad direct la HARVARD RADIO LABORATORIES Beets* f, Mass. Tubas istarsad Parte! Peer a t. 0. "The Little Wooder" FOR BOYS AND GIRLS CRYSTaAL SETS Unm—miUd-Nmt l^'SO Catches distinctly everything broad- casted within 30 miles. We also manufacture the "Little Wonder" assembled set at 96.00. GUARANTEED TESTED CRYSTALS Galen* 15c Raditisite 20c Write for Free Catalog It lists an ear radio parts aad _,r . Holloway Elec Supply Co, lac 2J8 Talrrl Are. New York City LOUD SPEAICER ScienttficaeV Perfect /\. ■ ' pnfiarB and Adjust- ing. Just connect re- ceiver and Enjoy Perfect ■ \ Radio Entertainment Written Crurantao of SertJofectien cr Money Back. Type D. H. No. 1020, $35 Fva B. Nov York Dealer* writ* for tptoial trade proposition. JOLLEY RADIO CO. 23 Washington St, New Yerk Digitized by Google

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RADIO WORLD 1 Shall WHN Remain Silent on Certain Nights? EDITOR, Radio World: As you are probably aware, Station WHN, Ridge- wood. Long Island. N. Y., has been asking, on the air. for the past few mghts for letters from the radio audience as to whether they want WHN to be silent on certain nights for the purpose of allowing the "DX fans" a chance to listen in to long- distance stations, or whether they want the late evening programs (10:30 to 12 p. m.) to continue. . , „ I know of numerous DX fans who on account of not being able to tune out WHN. don't listen to him at all. . I would suggest agitation as to having a rule passed to compel all eastern stations to close down at, say, 10:30 every night Also, how about allotting a different wave length (not 360 or 400) to those stations which, on account of having late hours allotted to them, have no alternative in the matter but to interfere with us DX fans on account of their late hours? Personally I have nothing against Station WHN as I think their programs are very good considering the fact that they are a low-powered station; and. as far as I have heard, they don't advertise themselves in any way. They evidently must be under a heavy expense, and it is all done to please the radio listeners, with no hope of return. In conclusion, would like to say that all DX fans, I am sure, will appreciate any- thing you may be able to do in this matter. March 10, 1923. H. D. Struixeb. Ill Broadway, New York City. Prize Essay Contests on Radio Subjects THE management of the American Home and City Beautiful Association Exposi- tion, to be held on the Million-Dollar Pier. Atlantic City. N. J., this summer, has com- pleted arrangements for conducting a nation- wide essay contest on the following subject* : "The Best Way to Educate the Public on Radio"; "Why Radio Should Be in Every Home, and How It Can Be Done ; Who Shall Carry On and Pay for Future Broad- casting?" and 'The Complete Radio Set as the Logical Installation." The following men, prominently identified with the radio industry, have been invited to be represented on the Board of Judges for awarding prizes to winning contestant*: Dr. Lee De Forest. De Forest Company. Newark, N. J.; Paul Godley, Adams- Morgan Company, Upper Montclair, N. J.; A H. Grebe, The Grebe Company. Jamaica, L. I.; General J. G. Harbord, David Sarnoff and P. Boucheron, Radio Corporation of America. New York City; M P. Rice. General Electric Company, Schenectady. N. Y.; Dr. W. H. Easton, Westinghouse Eiectric & Manufacturing Company, East Pittsburgh, Pa.; Paul Findley, Western Electric Company. New York City; Major - General George O. Squier, Chief Signal Officer, U. S. A.; Dr. A. N. Goldsmith. Director of Research. City College of New York; Roland Burke Henncssy. Editor. Radio World. New York City; H. Gerns- back. Editor. Radio Kens: Major J. Andrew White, Editor, Wireless Age: Kendall Banning. Editor, Popular Radio; Henry M. Shaw, President. Radio Trade Association: Lawrence A. Nixon. Editor. Radio Dealer. Secretary, Radio Trade Asso- ciation, and Jack Binns, Editor, New York Tribune Radio Section. Tho^e who compose the Roard of Judges also have been appointed as the Radio Com- mittee for the Radio Exhibit. The above committee will also direct the essay con- test and award prices to winners in a con- test in which only radio fans or those who listen to broadcasting arc eligible to submit essays on the subject. Prize Winners at the Perma- nent Radio Fair, New York City THE winners in the prize contests for amateurs at the Permanent Radio Fair. New York City, have been announced as follows : For the smallest one-tube, portable set— * First prize : R. S. M. Long-Disttnce RecetY- ing Set. manufactured by the Boston Scale and Machine Co. — Won by Fred W. Proctor, Hotel Ambassador, New York City. Second prize : Eagle Radio Portabloop —Won* by Milton Brownshield, 1922 Wallace avenue, Bronx, New York City. For self-contained home-made, three-tube, dry-cell receiving set — First prize: Paragon RD-5 and A -2 amplifier, manufactured by Adams-Morgan Co.— Won by W. H. Spald- ing, 27 Monroe place, Brooklyn, N. Y. Second prize: two-step amplifier, manufac- tured by Acme Apparatus Co. — Won by Carson Borthncy, 168 West 4th street. New York City. The prizes are on exhibition in the Broad- way window of the Hotel Imperial, New York City. The Permanent Radio Fair has had several requests to hold another con- test, and would like to hear from radio fans as to just what kind of contest they would like to have. I BOBBINS RADIO DESK The Place for Your Radio Set and Equipment domed compartment* for Batteries, Head Set*. Tool*. Extra Parts and other Appli- ance*. Useful and ornamental la any with a recoY.ng act. Ia oak and any fioieh. Send /or IltuMtraUd Literature. BOBBINS WOODWORKING CO. UBEJtTYVIUJE. ILLINOIS A DAY Sc///no .J >irts _ ■fclrt MiiuMttrv wuti tifnti »o .tea oompItU Hit* of shirt*. |«)tmit*. ba4 Dlrbtablrts dirwt to w**t>r. a>1 ▼•rtltmi brauvd -eicloalvf pattern a -#-»ar to b*ML Ha eip*M>1enr* or r*,|'it*l r* qtUrwd. KntlrHf n*w pmpnett i.kl Writ* foe JVw* MeiMfi. Navv Dirigible to Make Polar Flights DURING the coming summer, when the ZD-1, a navy dirigible now under con- struction, is placed in commission, she will be sent on a flight around the world and on trips to the North and South poles. Rear-Admiral William A. MofTett. Chief of the Naval Bureau of Aeronautics, announced on March 6 in an address broad- cast from WJZ by way of the Waldorf- Astoria, New York City. Short-Circuited His Purse "That doctor is a regular human dynamo." "Yes, and when I came in contact with him I myself was highly charged." — Scitnct and Invention. BUILD YOUR OWN SET THE RADIO CONSTRUCTOR PRICE 25c MAILED TWb !>•<- edit lea of TOTE RADIO CON SITU' CTOR <)u*t sff the preaa) Illustrate* and full* d«er1.w») the eMail popular ami ffflrleal heott vt* Pull ami tomplvte Inelnnilortt foe emiatrurtl-wt «f Hewelling Reinartz Relex Honeycomb A ad Maaj etaar Tern Tela la tka aaat rm bat* baae vaitJat let. Oat H lade? fraai i«ar dealer, at It will k» Ballad ra* paatsald aa raaelpt ef eatr i»e DUt LI RSI WRITS FOR tUAHTirY »*I0UI S. NEWMAN A CO, P-bBekec. » Nr St. Dept. W, New Yea* City WALCON Radio Frequency Transformers THB REST YOU CAN BUY WAIXON T i nil i i i aae •eetW aa . ia.ua tar ae» with WJX-U taaVee. Few an l uh aye, kaili frig a aew raaVat ekwett tm char** wttk east ll liailli nr. Pric* MjN. We nmj »a*U|» THE RADIO CENTRE, 2 West Broadway, N. T. FILL OUT AND MAIL NOW SUBSCRIPTION BLANK RADIO WORLD RADIO WORLD 1493 Broadway. Sew York C Please send me RADIO WORLD for months, for uh please find enclosed $ S1BSCRIPTION RATES: S r.gle t'opy % • Three Sluntha I SO Six Montha J» One Yrar. 52 Ia»ue« 6.00 A.M tl UO a Year to Foreign IVntage. 50c (or Canadian Foat- Digitized byGoogle

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26 RADIO WORLD DX Nite Owls (Continued from page 20) Proud of His Record From Jack AlUon, New York City. ON a recent night I heard the following list of stations: WGY, WAAM, WIP, WSB, WDAP, KDKA, WOC, PWX, WOO, WWJ, WJAX, WDAF and WAAN. I think that I have made a good night's DX work. I am using a honeycomb coil set with one stage of audio amplification, RADIO LOUD SPEAKER FOR PHONOGRAPHS Ibe M0BJU8ON Lmd Speektat Unit, far owe m nhntwnf . ukM the place of awkward! hea desks. Pmiim • too* value 100% true — u oahlsio— n never before attained In a laud epeaker. Attaches in PttM of Bapradaeer Mips an tone-ana of phoBatraph la place of r»- prqjtaeer. ar au> be and with bam. Adapted M any bulb a* with one or man hum of aawllSaa- tlon. Adjaatabto from sett to load tana. OaM possibly rattla ar loosen tbranih anaajli* aaa»n> neatlon. A popular-priced Laad Speaker that compares with meet expensive laatnuaanta aa tha market. Irwooonda In one, flrlai perfect carlo- faction. Handsomely alakal plated, oompleto with 8 ft. eord, 110— at year dealer's ar (Brest. Bant a O. D.. If desired. Fenj awanntoed. Meney baak If net aatJsfled. (Whan ardarlni. opacify make at pbanaarapb). MORRISON RADIO LABORATORIES Daat It. Lrali Blnk Datralt Hlea. New York Prices DIRECT TO YOU A Money-Back Guarantee Goes With Everything We Sell WE SELL ONLY STANDARD PARTS AT LOWEST PRICES Atwater-Kent Variometer* $8.75 Atwater-Kent Variocoupfera 8.75 Raven Molded Variometer 4.80 Raven Molded Variocoupler 4.W Weatlnghouee Dry Cell Tube tSO V. V. 200 Tubea 4.4* U. V. 2*1 Tubea S.7S Cunning-ham 301 Tubea 5.7S A. B. C. 23 PL Condenser 1.90 A. B. C. 43 PL Condenaer 2J6 A. B. C. 23 PI. Vernier Condenaer.... 3.7S A. B. C. 43 PI. Vernier Condenaer.... 4.tt Acme Audio Tranafbrmer 4.00 Baldwin Type C Phonea (double) 8.7S Baldwin Type C (single) 4.50 Stromberg-Carlaon Phonea (.00 Radio-Receptor Phonea 3.58 Federal Phonea 5.00 Bran dee Phonea O.OO Bradley atata 1.70 Many Other Bargains. Complete Stock. Write for Prices. Send Money Order or Certified Check and include Postage. GLOBE RADIO SHOP 115 West 23rd Street New York two 43-plate condensers, and, although I have not heard as many as some of the other fans, I am very proud of my home- made set Another New One Due to Crystal Not Re-radiation From Leo Schecter, UJS Semple Ave., St. Louis, Mo. I WROTE to you some time ago about my reception with a 1 -slide crystal set Since then I have received a new station, WLB, Minneapolis, Minn., and am receiving other stations much louder. I think the reason for this is because I am using crystals sold by the Rusonite Company, advertised in Radio World. I have come to thnk that my tuning-coil is not the reason for my recep- tion, because I have just built a 2-shder and have heard WCX and WOC in one night on it. The reason for my wonderful recep- tion must be in my phones, which are 509 w. Western Electrics, and my aerial, which is a 2-wire. 85 ft. long and 36 ft high. Many people have told me that my reception is due to re-radiation, but two authorities, Mr. Flewelling and Dr. Greenleaf W. Pickard, famous radio inventor, both say that re- radiation is impossible. I will be glad to give the details of my 2-slider tuning coil to anyone who writes for them. STANDARD APPARATUS AT ATTRACTIVE PRICES Watch This Column EACH WEEK It Will Pay You HEAD SETS Lilt Price 18.00 Brandos 8.00 Dictograph .. 8.00 Federal 2200 Ohms 7.50 Stromberg Cerlxn 0.00 Froet 3000 Oheu Super lor. Our Price IS. 50 5.75 4.03 4.75 8.00 B«yl1»ii"...'~T7.. s'?B 5.50 Murdoch Type 57 4.' in '.Hi E,Ktr,t 50»w «.M 'Hi ftf",1" Ty" c- 8.50 8.00 Baldwin TVpa c. Blatla 4.00 LOUD SPEAKERS 1101.00 Wert*rn Eleetrle 8145.00 55.00 Western Eleetrle 58.00 «*••» "»?"*vox (New Type) 31.50 40.00 Callophone 30 00 20.00 Dictograph 15 00 15.00 Brlttaala 12.50 AUDIO TRANSFORMERS $7.00 Federal 15 «n 7.00 Radio Corp. U. V. 712 5.6O 8.50 Raoht 5.10 4.50 Thorderion 3.00 8.00 Amplex W. 0. 12 3.J5 5.00 General Radio 4.35 0.00 Jefferson 5.00 7.00 Amertram 5.95 5.00 Aeme 4.10 PANELS BAKELITE — 3/16 Inch Stock 7 X 10 $1.35 7 X 13 $1.95 7 X 12 1.45 7 x 18 2.50 7 X 14 1.85 7 X 24 2.95 HARD RUBBER — Grade A 7 X 10 $0.90 7 x 18 $1.45 7 X 15 1.35 7 x 24 1.90 SPECIALS Firth 23 Plate Condenser $1.30 Firth Triple 8oeketi 90 Firth Double Socket! 70 Millard Rheortata 45 Double Phone Cords 60 Foda Type Switch Levers 23 Firth Crystal Detectors 1.00 Braeh Lightning Arrestor 1.23 Bulldog Phcne Plugs 1.00 Three Coil Mountings 3.50 Two Coli Mountings 2.75 Single Coll Mountings 50 180° Varloeoupior 2.79 Variometers 2.75 Vernier Rheostats 1.35 1 1 Plato Condenser 1.35 43 Plato Condenser 2.15 WDM Sookets 30 Full Lino of Ail 8TANDARD SETS and AC- CESSORIES at Greatly Reduced Prices. Write for Our Quotations. All Mail Orders Shipped en same day as received. Send Money Order including Pootage. STUYVESANT Radio Corporation 15 B. 14TH STREET. NEW YORK CITY Bet. 5th Ave. and Union Square White's "Variomamt" Cement Make year eaa cello. Ceertreet vari caterers, verlo- ooualors. etc No distributed capacity. Holds (Had. lata securely and perteaaeatty. BANK - "- FOR WOUND COI "Far this operation of cemoatlno the tbrao turns together sheilas will act da."— Radio World. March 10. Send 26c. for sample bottle WHITE RADIO COMPANY 123 East 23rd Street New York Orty WANTED Thorough Radio Man Experienced in vacuum tube re- pair; preferably one experienced on WD-11 tubes, but not absolutely necessary. Answer, giving full par- ticulars, references, experience and salary wanted. THE COLUMBIA PRINT 1488 BROADWAY NEW YORK CITY WHERE SPACE IS LIMITED The No-old Small-space Socket Is moulded (rem Kenulnc Condnudte. Requires but email apaeo fat mounting. Special clot reinforcement; virtually mv broakablo. No exeesa metal to Interfere with 083- clency. Phosphor bronie contexts. Cannot bo affected by heat. Exceptional value. Equal In quality to any socket using bottom con- tact. Attractively boxed. Display container furnished for dealer a counter. ALDEN MFG. CO. Formerly Alden-Napler Os. DsaL U 52 Willow I Springfield. We Recommend For Investment HENNESSY RADIO PUBUCATI0NS CORP. PREFERRED STOCK (Pablishers Radio World) Complete detail* tent free upon request Frank T. Stanton & Co. Specialists in Wireless Securities Since 1917 35 Broad St New York Tel. Broad 5818-1870-3841

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RADIO WORLD 27 KING SR. VARIOMETER 159 to CM Meters Nt ratal* eenaoetleg liurdware iiswf—raduelei capacity Iww. Rugged — MM. Sin 4%"x Cuarantetd by manufacturer direct to user. Retail price $£50 Aifc yrar dealer franco Mfg. Co., 30 E«t 23rd St., N. Y. C" 12IM-OHM Llrt Price Tie. RESISTANCES IN STOCK For tin Niw Super Olroalte RADIO STORES CORPORATION DISTRIBUTORS ......... lit W. 84th St. M. V. OHy Ueoaera IS! IS-S8I0 The dials with absorption reduced to a Minimum Specially deafened eroee-eeeuen Incline aUnljeaai t„SC IkmawL graduation and number! are imrtasa- larfr dear. Kneb ea shaped that flniera da net In- terfere with tear, aerorate reydtac. Na-ald dUh) are mated (ran imuln* Na-aM material. Bheoettt beat will net affect them. Ihey 'eMNCH DIAL See .-to* dial for J"-^^.- 50e: Bend etamp for literature. Alden Manufacturing Co. Formarlj Aldea-Napler Company 51 Wlllaw St.. J MriatSaM Dept. lm PROTECTION TELBRADIO FILAMENT PROTECTORS 'Far arawtar and nmpllfy- tM taboo. Prlae. Slaila Pole OOe.. DeaSIa Pel* JlOe. Ranewal faaei 10a. neb. TELERADIO LIGHTNING ARRESTERS XlMtrleal No. 688T Tb. eaty A-«»T"hM^tW W'<• and metbodo of iruej an duwaaaed at length. ab^r-3^ ^v„u^. Dan. its aaam Its — , lUu __ Prlae. «1.U THE COLUMBIA PRINT Raw Yet* Ok? The Passing of the Publishers' Friend The passing of Stephen Farrelly removes one of the big figures from the periodical and news distributing trade in this country. Mr. Farrelly was eighty years of age, but he came of that sturdy stock to which the calendar means nothing and was active al- most to the end. For many years he was a moving force in the conduct and counsels of The Ameri- can News Co., which owes so much to the activities, loyalty and strength of character of the members of the Farrelly family. Mr. Farrelly was helpful to and sym- pathetic with all the great American pub- lishers, and never too busy to give his ad- vice to the younger members of that craft. His big friendships and his effect on the business, social and spiritual life of New York were fully indicated by the immense assemblage of noted men and women from all walks of life who attended his funeral services at the Cathedral in New York. Mr. Farrelly will be missed by his as- sociates and all those who knew him, but at least his family have the satisfaction of knowing that he passed out into the Great Beyond full of honors and with the love and respect of every one with whom he had come in contact during his many years of business and public service. Broadcasting Station Has Plate Glass Walls THE Edgewater Beach Hotel, Chicago, will soon have a new broadcasting station, with the call WJAZ. It will be located on the main floor of the hotel, and its walls will consist of three thicknesses of plate glass. Spectators will thus be afforded a full view of the station in operation. NationaTRadiu ScRvice Zv" 140 W. 32nd St. New York, N. Y. OCTAGONAL SHAPED LOUD SPEAKER Handsomely F i n- ished in Gun Metal for Use with Head Phones— SPECIAL $4.50 Sheltone Load Speaker.. $350 HEADSETS Baldwin Type "C" $8.50 Brandes 2000-Ohm 5.95 .Federal 2200-Ohm 525 Bannard 2200-Ohm 3.45 Murdock 3000-Ohm 3.95 MISCELLANEOUS -.006 Westinghouse Cond. $0.60 .006 Freshman Cond 1.00 Antenella 1.75 Bulldog Grip Plug 75 3 Plate Vernier Cond.. . . 125 EVEREADY "B" BATTERIES No. 763— 22y2 Volts $1.25 No. 766— 22y2 Volts 2.35 All Merchandise Guaranteed We Pay the Pontage HAKE PERFECTION YOUR SELECTION ITU 17 17 t A Sl-ZS Voltmeter or Ammeter wil be riven rXVCiCi. Free with each purchase of S5JS or over. Every Product Sold on A MONEY-BACK GUARANTEE— Perfection Pave Parcel Post. Uat LOUD SPEAKERS Prlae Brletel (22.90 Patho Magnavex Woodehern, Nevort 22.00 49.00 7.S0 Medal HEAD SETS Rice, 3000 ekaw 17.00 Dictograph. 3000 ehmo 12.00 Patter Praelalea. 2200 ehme 9.00 Baldwin Type a Natb. Baldwin.... 12.00 Baldwin Single Pbeee Type 0 0.00 N *. K, 6000 ehme, made In Gar- many. Tba bait a hones mada 10.00 TRANSFORMERS Therdaraen Audla Frequency 14.90 WD- 12 Audla Freeueney 5.00 AMI Type A28 5.00 VARIABLE C0NDEN8ERS Variable. Fruuoa. 43 Plata. Vernier 23 Plata. Moulded 43 Plata. Maulded Franco, 23 Plata, Veraler FILAMENT 37.70 3.00 4.00 Endi, .0005. Ends. .001. Variable, with 0.60 RHE0STAT8 Our Prim $18.80 17.50 29.76 •.SO 14.25 6.90 5.50 i.75 4.SS 7.50 13.25 4.O0 4.50 $4.75 1.50 2.00 V. T. SOCKETS aale Sockets, Braae TuMao Double 800k ota, Breae Tublag Trlela Seakata. Braae Teblee Slaila Seakata. Red Maulded Cee- WD. LM Our Prlii Price 11.00 "oS 2.00 3.00 1.35 1.00 .55 1.00 At 35.00 $2.50 5.00 2.50 6.00 3.50 S.00 5.50 $5.00 $2.25 5.00 2.50 5.00 2.50 6.00 3.30 8.50 5.75 3.00 2.75 Moulded. Fade Type. 6 abma. I ft Amperea $1.00 Cutler-Hammer 1.00 Outler.Hammir. Vernier 1.50 Klomer, Vernier 1.50 Framlnobam. Veraler I. SO Am too Potaatiemetere. 360 ohms Resistance 1.75 JACKS Fine Open Circuit $0.70 Fine Cloned Circuit 65 PLUS8 Flat Pluoi $1.00 Round, Bulldeg Brlp 1.25 DIALS AND KNOBS 3" Compeeitlon Dial and Kneb. Vt" Braaa Buihiai $0.75 3'/«" Unbreakable Dial and Knob, Vt" Nolo 1.00 4" Cempoaitlon Dial and Kneb. •A" Hole 1.25 3" Compocltion Mai and Kneb. Hale, Tapered Knob 1.00 4.25 $0.40 .05 1.35 .75 1.16 1.00 $0.40 .50 $0.50 .00 $0.30 .50 .50 .40 Seakata. Extra Fine Quality VARIOMETERS Flaher Manooany France Mahatany Patho Moulded Eaole. Red Moulded Bakellte VARI0C0UPLER8 France Maaefany. 811k Wcund. Fibre Tublao Fiahar Maheoaay F loner, 180 Defrew Petbe. Moulded, Silk Wcund Eei li. Moulded, Red Bakellte, the Beet Mada Franco. 160 Dairaee. Bakellte, 8ilk Wound BATTERIES Exlda "A" Storage Battery. 6 V.. 80 Ampere Heuri, Type 3 LXL.9 $23.10 Exlde "A" Sterile Better*, « v.. 120 Ampere Heura, Type 3 LXL-13 31.50 Brlont 8tar "B" Battery, 22'A V. 1.75 Brlfht Star "B" Battery. 5 Positive Terminals. 22'/. V.. Variable.... 3.00 Brlont Star "B" Battery, 7 Positive Terminals 43 v.. Variable 5.00 MISCELLANEOUS Homcharaer, DoLuxo Model, for AU tarnatlno or Direct Current 18.50 Post Electric Selderlna Iron 6.00 PANELS Hard Rubber, Uabreokable. 7 x 10, New Hard Rubber, Unbreakable, 7 x 18, Now Hard Rubber, Unbreakable. 7 X 24, New. RECEIVING SET8 $50.00 Tueka Reeeneratlve Armstrong Circuit One Tuba Set. 8»eelal $25.00 125.00 Cutting 4V Washington 3 Tuba Re- generative Armatreao Circuit Set. Will Receive Over 2000 Miloe. 8pedel... 65.00 $10.00 25.00 1. 10 2.00 3.50 16.30 4.75 $0.90 1.60 2.30 When ordering ask for our free complete catalogue. PERFECTION RADIO CORP. OP AMERICA 119 WEST 23rd STREET, NEW YORK CITY WHOLESALE , ( ^ n;2l;t: RETAIL

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28 RADIO WORLD DO YOU WANT TO BUT. SELL OR EXCHANGE RADIO OR OTHER GOODS T DEPARTMENT AT It A TRY THIS RADIO WORLD'S QUICK-ACTION CLASSIFIED ADS Thii department U intended for everybody who wmata qakk action on short announcements corering the buying, exchanging or general merchandising in the radte fteld. Renders of RADIO WORLD will find that it pays to read these cabana every week. Advertisers will get a tea-day service here that is, copy received for this department will appear in RADIO WORLD on the news-stands ten days after copy The rate for this RADIO WORLD QUICK-ACTON CLASSIFIED AD. DEPT. is 5c per word (minimum of 18 wore* including address), 10% discount for 4 cosaocottve jnsirtieni, 15% for 13 consecutive insertions (3 months). Changes will be met hi standing classified ads. if copy is received at this office tea days before publication. RADIO WORLD CO, 1493 Broadway. N. Y. C (Phone, Bryant 4790. ARE YOU ALL RECEIVING Porto Rica, Havana, Florida, Denver, Kansas City, San Antonio, Texaa. and other*? Send twenty-five cent! in coin and I will tell yon how I do it. VARIABLE CONDENSERS at factory price*. 3 plite. $1.05i_n plate. $1.35; 21 plate, ^^gL^ Elate, $2.05. Send cash with order. ui EAF, 34 Merchant*' Row, Beaton. Ulli. FOR SALE— "Hotncharger" battery charter, $14.00. Froit Fones, $4 00. Brandes Superior, $6-00. U. V. 20* Tube, $3.00. Volt-unmeter, "Pigjwlet" make, 0.30 ampere*, 0-3S volta, 0-3 volt*, alao Cadniom eRading, mounted in neat case, $15.00. All goods are new aad guarantaed perfect. ADRIAN SHANLEY, Aberdeen. So. Dakota. CASH FOB OLD GOLD, , Plateaus*. SDver, Bail ill. Liberty load*. War, Thrift, Uaasad Paeaage Staaaae, Fala* Teeth, Magnet* Paint*. Jafka. Aay VahuMea. Mail fa today. Cash aent. retara saaK Geed* returned la tea aay* if you're not *ati*aed. OHIO SMELTING 00.. $37 HJg- pedresae Blag., Oevalaad, Obi*. PATENTS PROCURED AND TRADE MARKS REGISTERED— Advice and tanas noon request. Robb, Robb & Hill, 1403 Hanaa 2dg.. Cleve- land, Ohio; 942 McLachlan Bldg., D. C. It** a simple let, eaiily operated, (elective, good volume and range. Every radio fan write. Don't mi** it I B. E. BROWN, Lincoln, Maine. FOR SALE— Variometer* and vsxiocoupler*, Eeach, 3000 meters. Receiving transformer*, Anthony Sim, Box 123, Shoreham, Long d, N. Y. CRYSTAL-TUBE for Crystal Seta. See adver- tisement on page 23. GET RESULTS — Build a real crystal set by uting long range crystal coils. Range 59 to 500 miles. Colli and hookup, $1X0, postpaid. L. S. Muster, 2407 Jackson St., Anderson, Indiana. SPRING RADIO SALE— Here'* your chance to buy quality radio apparatus at wholesale prices. All make* of apparatu* and parte. If interested, send postage for complete fist N. E. Ristey, Spring Grove, Minnesota. FOR SALE— Paragon Regenerative receiver, R.A.10, Detector, and two-step D.A.Z Both $110.00. Crosley two tube set, $25.00. All ap- paratu* new and guaranteed. Write Philip Cob- lenti, Middletown, Maryland. RADIOFHONO Adapter—Your Edison, Bruns- wick Victrola or other talking ««-«-Ki— has the finest acoustic properties possible. Radiopbono Adapter enablea you to use it a* a load speaker. Patent (Pend.) Molded Construction. Seat oa money back guarantee. At your dealer* or direct from u*. $2.00 poet prepaid. Industrial Sale* Engineering Co., 671 Broad St., Newark, N. J. MAKING MONEY WITH YOUR SMALL CAMERA, 10c. coin. Wm. Kissel, Box 114, Adrian, Mich. EXCHANGE JOLLY, INTERESTING LET. TERS through our club. Stamp appreciated. Betty Lee, Inc., 4254 Broadway, New York City J. MULBERG, DEALER— Radio Seta and Sup- plies. Key West, Florida. SOLDER YOUR RADIO CONNECTIONS with Radiol, the new soldering paste. Price, 29 cents. Dealers write. DAVIS PROCESS CO.. 21» Devee St., Brooklyn, N. Y. HOW TO REPAIR Vacuum Tube*. Complete literature, $1.00. Box 103, Station C, Toledo, Ohio. BATTERIES— Ediaon Storage "B" Battery Elements, 5c per pair; 18 will make one 2U volt Battery. OILMAN'S BATTERY SHOP, Chelsea Sq., Chelsea, Mass. VERNIER VARIABLE CONDENSERS — Ca- pacity, .0006. $1.48 postpaid. Fully guaranteed. Cherpeck Company, 3123 Davlia Court, Chicago. EXCHANGE LETTERS with friend* every, where. Pleasant pastime. Information for stamp. Smith, Box 3125, M. Portland, Ore. OLD MONEY WANTED — $2.00 to $500.00 EACH paid for hundreds of Old and Odd Coins. Keep all old money. Send 10 cents for New Illustrated Coin Value Book, 4x6. You may have valuable coins. Get posted. We pay CASH. Clarke Coia Company, Ave. 83, Le Roy, N. Y. Address Wanted:— The address of Arthur Kimberling. Write Business Dept., Radio World, 1493 Broadway, New York City. DO YOU WANT TO SAVE MONEY in making your set? Send for the Tan. 27 issue of RADIO WORLD, containing a full-page draw- ing os '. ' to make filament control rheostats, as ■ . easily understandable text, which r auction easy. 15c a copy, or ;»tion with this issue. RADIO ■idway. New York. WTJUNQ A HOUSE. By Herbert Pratt. _ a ha*** already befit; tells jut how to start about wiring It; where to beada; what win *s uaaj how to run it according to tasursacs rules; ta fact, iaetja* batsraaariea ywa a— d. Direcrieeaap- ltA *Pr3t!° ^"^BraaJwty*. B^Y C^Frleei STANDARD ELECTRICAL DICTIONARY— By Prof. T. O* Conor Sloane. Just issued aa en- tirely new edition brought up to date and greatly enlarged— as a reference book this work is beyond comparison, aa it contains over 700 page*, nearly SOS Ulu.trstions, aad definitions of about MOO distinct word*, term* and phrases. The defini- tion* are ten* and concise and include every term used ia shujtrioal scseajca. 7ST peg**, 417 illustration*. (See page 18 for fuller description.) Price, $5.00. The Columbia Print. 1493 Broadway , New York City. RAND-McNALLY RADIO MAP OF UNITED STATES— Is 28 x 30 inches in sis*. The locations of broadcasting stations are shown by distinc- tive symbols. The call letters of each station are given, alao the wave length* of each. The Radio Districts with number* are shown In red and the Radio Relay Divisions are in blue. Tune zones are included. Alphabetical list* of stations and alphabetical lists of call letters are in the margins. Convenient pocket form with cover. Price, 35c. The Columbia Print, 1493 Broadway, New York City. A COURSE IN MECHANICAL DRAWING— By Louis RouUlion. The anther has writtsa a moat practical book on the subject of Mechaaical Drafting. It fully explains the art of Drawing, Lettering and Bisaeasiooing. It I*, by far, the moat practical book ever published oa this sub- ject, for use in day and evening schools, and more especially adapted for the teacher and for ■elf instruction. Fifteenth edition, revised aad •ntorged. TjUj uTuatreted. OMaag. COLUMBIA PRINT. 1493 Broadway, N. Y. C Pries, $LSe, BUILDERS AND EXPERIMENTERS. Do you know that the Reflex circuit is one of the most interesting circuits to construct? You can not guess how much fun you are missing if you fail to try out at least one of these circuits. See RADIO WORLD issues of Feb. 24 and March 3. They contain two fine articles by W. S. Thompson, with plenty of new Reflex circuits to experiment with. Don't miss these! 15c a copy. RADIO WORLD, 1493 Broadway, New York City. HOW TO BECOME A SUCCESSFUL ELEC- TRICIAN—By Prof. T. O Conor Sloane. An in- teresting book from cover to cover. Telling in simplest language the surest and easiest way to become a successful electrician. The studies to be followed, methods of work, field of operation and the requirements of the successful electrician are pointed out and fully explained. 202 pages. Illustrated. Nineteenth revised edition. Cloth- Price Jl 50 The Columbia Print, 1493 Broadway, New York City. D AGENTS— Are you interested in radio? If n drop us a card. We have a proposition no in agent should turn down. Meet* the Beak of 90 per cent, of the public THE WILKENDA CO. 500 Fifth Avenue. New York City. Dept SUPER-SIMPLICITY CIRCUIT— 1,000 to U> miles on one tube, one control, 150 to 2JRD meters. No rheostat, storage battery, vans coupler, variometer, 3 -coil mounting, vsrfsab inductance, tape or radio frequency. Notmat to guess about. Complete hook-up aad particulars, $1.00. No check*. Build your own. Save SOX and get better results. RADIO EXPERIMENTAL LABORATORY, Box 194 A, Berkeley, CaEt GUARANTEED VASUOCXXJPLHkS, *■»- RADIO ASSEMBLY, 1109 Valley St., Jopka, Ms. VACUUM TUBE RESULTS WITH A CEYS. TAL SET!— Cover distance with a "PT" ULTRA- SENSITIVE CONTACT in your crystal defector. Beats gold and other ordinary catwhiskera DOES NOT JAR OUT. Using the "PT," Myrle Wood heard over 43 broadcasting stations m a thsusssd mile radius I Other users testify: "Heard ssv stations on first adjustment. Haa all adraetagw you claim. Receives music so loud it hurts *» ears." The "PT" has received 3.300 mile* tkrouft static. Price only twenty -five cent*. "FT" CRYSTAL CONTACT COMPANY, Boa 1641, Boeton, Maaa. MODEL MAKING— By eUynsood Francis Tata. A new book for the mechanic aad saedei ssssar. This is the firat book of its kind to be paMahsf ia this country, aad all thaee interested ia sssssl saaHsssriag should have a copy. The first eight chanters an devoted to such subjects ss Suvsr P^W^T0=;.-etc^r^ twenty-four chapters describe the coastractlss of various saedei* each as rapid fin naval gas*, «3 P?8»e. 3«1 uTustratiocia Price, nST lis uolumbU Print, 1493 Broadway, New York Off. DYNAMO BUILDING FOR AMATEURS— Or ?1T to Construct a Fifty Watt Dynama-Bj Arthur T. Weed. A practical treatise saovinr in detail the construction of a small dynamo or motor, the entire machine work of which can be done on a small foot lathe. Dimensioned working drawings sre given for each piece of machine work, and each operation is clearly de- scribed. This machine, when used as a dynamo, haa an output of fifty watts; when used as a mo- tor it will drive a small drill press or lathe. It ^ « drive a sewing machine on uy Jith ^J^.T'7 •work- /H".000* fllostrited witn more than sixty original engravings, shov- ing the actual construction of the different part*. BrrSl "'""v THE COLUMBIA PRINT, h£ Broadway, New York City. ^TWErpiETH CENTURY BOOK OF RECIPES, ??lD/,Hl»^ Jhis book of 880 pages is the most th^.^.^? °f n*io««ve«r published, giving thousand, of recipes for the maatifactur* oTvalt able article* for cvery-day use. Hisu, betas, ESk^ii. * lnd,*ecr« proceaaea are re«sj3 within its pages. It coven every branch *f tht useful arts and tells thousands oTwayiM *sak»» "°"'7 and is just the book everyame akaald ssv. ?iJj^Mn<L,-TI,e n»«M *re oBsd with oat ten of intense interest and immaasursMe prac- ISiS! *?u the Photompher. the perfmaer, the painter, the manufacturer of gtnas, psstea, cement* and mucilages, the physician, the drag- gist, the electrician, the dentist, the engineer, me foundry man, the machinist, the setter, tht tanner, the confectioner, the chiropodist, the sua ufacturer of chemical novelties and taflet srav antioaa, the dyer, the eieetrwamter. the sasaMkr. the engraver, the glass worker, tie nH-btster, the watchmaker, the jeweler, the iak msntase- turer, the optician, the farmer, the da by nun. the P*pe5i.B?kir' !h?, worker, the sssp aaker and the technologi.t in general. A hook t* whfch you may turn with confidence that you wifl tsd what you are looking for. A mine of informs Hen up-to-date in everv respect. Contain* ss hs- mense number of formula* that evarysat aauu to have that are not found m any otter oert New edition. 807 octavo page*. Cloth Madng Price. $4.0). The Columbi. Print, UH Broad-*?. Google

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RADIO WORLD 29 Tune in to WDAP —the powerful broadcasting station at o/>' POST ELECTRIC COMPANY, (Dh. S*W) 30 E. 42a*J St. N Awarded CerUleate of

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30 RADIO WORLD Here's Your Radio Library! Useful Technical Articles Published in Former Issues of Radio World APRIL L A 600- Mile Radiophone Bmptoylag a 5-Watt Tube, by Frank A. HabneL "Toll Me Please, How WU1 Thii lot Re- ceiver' bj B. L. Bragdon. _ Short Oats tit Reesirer-Olreart Design, by O. O. Roos. Making a Short- War* Regenerator, by Ml Chaa. Bhlert APRIL/ 8. Do Ton Know Tour Reoatrtag Jama* D. Gordon. Why » Crystal Is Called a Rectifier, by Wal- ter Bmmett Is Radlotelepkony Dependable? by O. O. Roos. Mounting Crystals la Tour Detector, by B L Bragdon. Storage Batteries for Radio, by Fred. Okas. ■Mart APRIL 16. _ First Principles of Deotrietty as Applied to Radio, by John p. Miles. Your Storage Battery, try B. U Bragdon. What Makes Radio Possible, by Bdward Ua- Oround Oonneetton as Vital as Antenna, by Fred. Chaa. Bhlart. APRIL SB. Valuable Pointers oa Aerial Construction, by ■award Llawood. What Is Meant by Toning, by B. L Radio- Frequency Amplification and _ ration, by Frank Armstrong. Honey-Comb Colls and Condensers, by Dd- ward Lmwood. Charging the Bragdon. How to ^Construct the Varloooapler, by Fred erf ok j, Storage Battery, by B L MAT 0. The Advantages of Radio Frequency, by Harold 8. Potter How tp Construct, Protest and Operate a wtorage Battery, by George W. May. The BeglnnoT>s Catechism, by Howard Un- it by It, by Ton^ and What Is Meant ilert. New Freaneney Amplifier Brings Wares In Strong, by O. W. May. MAT 18. My Practical V. T. Detector and Two-Stage Amplifier, by Frederick J. Romford. The Principles of Radlotelegraphy, by Wal- ter J. Howell. The Reason for the Loop Aerial, by George W. May. Tuning and What Is Meant by It, by B. L. Bragdon. The Beginner's Catechism, by Bdward Lin- MAT 27. The Beginner's Catechism, by Bdward Lta- BOd. How to Make Your Own Condenser, by George yV. May. Toning aa Applied to Telegraphy, by Walter J. Howell. Why the Condenser Doesn't Condense, by B. U Bragdon. Making Signals Loader with Two-Stage Am- plifier, by George W. May. JTJNB 8. The Cost of a Single-Circuit ReoslTor, by Howell W. MlUer. The Beginner's Catechism, by Bdward tin- How to Compote and Build a Fixed Conden- ser, by B. L. Bragdon. ^Design for an Amateur's ReoslTtng Set, by Simple Method of Recharging a Storage Bat- tery, by John Grayson. JTJNB 10. Radio ReoslTor for Short Wares, by George W. May. How to Filter Atmospheric Conditions, by C. White. The Messenger Boys of Broadcasting, by B. L. Bragdon. are Ton a Member of the N. O. D. C.T by B. by Bdward Ltn- L. Bragdon. The Beginner's Catechism, How to Construct One- and Two- Slide Toning Cells, by George W. May. JTJNB IT. The Vacuum Bulb's Start In Ldfe. by C. White. ^How to Select the Right Set, by B. L Brag- Tile Beginner's Catechism, by .Bdward Lin- wood. Test of Induotanos Colls, by Fred. Chas. Bhlert Short Waree from a Simple Reostrer. by Stanley Bryant JTJNB 34. Hmt to Make Tour Radio Cabinets, by W. 8. Standi ford. How the Crystal Detector Is Used to the [vantage, by C. J. Williams. How Construct s tire Reoelrer, by George W. - - - Dtion of flee Set 100,000 Times, byJohn Kant. Repairing Cracks In Hard-Robber Storage Battery Jars, by W. B. Btandlford. The Beginner's Catechism, by Bdward dUn- by Fred. Okas. Catoohlsm, by Bdward Lin- JOLT 1. Novel Unit-Detector and Amplifier, by Fred- erick J. Romford. _Why Ton Most Oss a Condenser, by O J. Williams. How Ware Lengths Travel, Bhlert. Radio World's Revised Dictionary, by Chaa, Bhlert. The Beginner's wood. Oss of the Vacuum Tabs Detector, by W. May. JOLT 8. Radio's Place In by B U Bragdon. H.TPtath.BaU°n °' *h* LAOM ^P'""' ■* Charles Armstrong's Soperregeneratlre Amplifier Folly Explained, by John Kent. Operating a Transatlaatie the Phenomena of Nature, Chaa. Bhlert. The Beginner's Catechism, Station, by Fred, by Bdward Ltn- Rednelng Strays and Static, by Fred. Chas. Bhlert. JOLT IS. Assembling a Detector and Two-Stage Ampli- fier, by H. 8. Stanford. Combined Radio and Audio Frequency Ampli- fication, by C. White. The Beginner's Catechism, by Bdward Lin- Locating Toor Aerial, by Harold Day. Facte for Beginners, by Fred. Chas. Bhlert JOLT 33. When Toor "Merles" Come by Radio, by Stan- ley Bryant Underlying Principles of the Vacuum Tube, by George W. May. Practical V-T Detector Panel, by Frederick J. Romford. Rerlsed Radio Dictionary, by Frad Ohaa. Bhlert The Beginner's Catoohlsm, by Bdward Luweed. Importance of Aerials to Radiation, by a White. JULT B). The Vacuum Tube aa a Transmitter, by Charles H. Plata. My 20- Kilowatt Tone and its Uses, by Irrlng Langmolr. ^ Importance of the Capacity Switch, by B. L The Troth about Harold R. Hart AUGUST B. How to Construct and Operate the Snperregeneratlre Circuit by John Kent Usf ■ ~ " ™ ' — • " ~ Lamp-Seeket Aerials, by Jslng Radio Freaneney to George W. May. Things Brery Radio Fan Must Know, by B Hawley. Rerlsed Radio Dictionary, by Bhlert AUGUST IX. The Work of the Audio-frequency Transformer, by George W. Msy. Practical Measurements of Capacity and In- duotanoe. by W. A. Dickson. Experimenting with Armstrong Circuit Pro- duces Unusual Hook-up, by Dr. 0. S. Kelly. How to Secure Perfect Regeneration, by Fred. Chas. Ehlert AUGUST 10 How to Build a Portable Field Busier, by De Witt H. Thompson. Using Two Tubes for Recelrlng, by C. White. The 8 to rare Battery aa aa Important Factor In Radio Reoeptlon, by Donald Van Wyok. The Use of Capacity In a Circuit, by George W. May. The Beginner's Csteohlsm, by Bdward Llawood. AUGUST 20 How to Build a Spider-Web Reoelrer. by Frederick J. Rumford. My Detector and One-Step Amplifier, by Fred. Chei. Bhlert ^The Beginner's Catechism, by Edward Un- Hlnts for Fans, by C. F. Rye. SEPTEMBER 2 Generating C-W for Transmission, White. by O. WCnders of Radio-Frequency Amplification, by H. 8. Ftottftl*. » 517 J° „ c°nnect *be Blectrlc-Llght Socket Aerial, by John K«nt Practice) ?r™'*-_ for Regenerating Loud Sig- nals, by O. 8. Kelly. •._R*d,0,.Illaa" for the Amateur to Teat On by Carl Hanson. How to Make a PraoUeal Ware-Mater, by Frederick J. Romford. How to make a Honey-Comb GoU with a Two- Stage Amplifier by Fred. Chaa. Bhlert Perfect Short-Ware Radio-Frequency Ampli- fication, by George W. May. SBPTBMBBR 18. How to Make a Two-Tube Superregenerater. by Frederick J. Rumford. Bradbury? * Ampllfylm« «l««sJa. by B Votes Distortion in Vacuum-Tubs Reeetvera. ey w. A. Dickson. „_Chargteg a Battery— from a French Radldst's poJ^^ View, by Martaa Thoorate. Working Diagrams for Begins en. SBPTBMBBR 28, 1922 P.NF7MetSe?00k"',P W°rth ***** OiK. »F White Metbon«nCT ligisirstor, uY&cr%°FD*wZ£jM Be,t te *• Broadcattinc Stations of United Stataa and Canada. Brook»R*dJ° Primer * * Re,Uble *»■«•» ^ Joha iSL'bZZ M R"UO Com-onicatkm. by OCTOBER a. .A »'™P'* Superre genera tire ReceJrsr, by Har- old S. Potter. Ehlert"lm "tjV* °' A"e,ter s,fe« h' Fred. Chas. gHow to Make Your Aerial Function, by Horace How to Avoid Interference When a 3C0 Meter and a 400 Meter Station Are Operating Simal- teneously, by C W. Horn. NOVEMBER 4 Receiver for Amplifying Week Signals, by Hoe- see Beers. How to Learn the Code, by Ortherue Gordon. VsrftWycrk~'I,d H°" TheT Work' bj DomaU NOVEMBER 18 Keift1'0 Device" You Sh°uld Understand, by John The Counterpoise, by Frederick T. Rumford. Chas "fhlert "lduct"nce and Capacity, by Fred. The Importance of Understanding and Testing Redio Apparatus, by C White. Operating a Three- Unit Honeycomb Regenera- tive Receiver, by John Kent. Any single copy of Radio World, be- ginning with No. 1, mailed on receipt of 15 cents postpaid. Any seven issues for $1.00. The abore 31 numbers seat for $4.40. Or send $3.00 for S months (26 num- bers) or $6.00 for 1 year (52 numbers) ami have your subscription start from No. 1. Radio World, 1493 Broadway, New York. Digitized by Google

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RADIO WORLD An Appreciative Subscriber Finds Value in "Radio World" EDITOR, Radio World: Realizing that the lot of none of your caste is any too happy, but that a word of sincere appre- ciation might brighten it a bit, I am send- ing this word of thanks for your good, practical magazine, and especially for your article by Ortherus Gordon in your issue of January 20, 1923. Before running across Radio World of that issue I had scanned several so-called radio magazines, with their articles, high- and low-brow, and their data on the con- struction of sets, and it was not until I saw your article that I had the courage to essay building a set The detail and clarity of that contribution gave me the necessary stamina, and I set about the purchase of parts and their construction and the build- ing of the set described by Mr. Gordon. After the usual delays— largely waiting for the receipt of good apparatus— I got the set together, and made it '^perk" on Feb- ruary 17. Since that date I have received the following stations: WEAF, WGY, KDKA, WJZ, WLW, WDAJ, WCAE, WJAX, WNAC, WHAS, WMC, WDAP, WBZ, WOR, WIP, WMAQ, WQAA WBP, WSB, WGM, WGI, KYW, WWJ and WHA. You will note that this list covers the territory from Boston to Memphis, via Chicago, and from Troy to Atlanta; all received repeatedly, together with a Los Angeles station received once. It is very difficult to tune in Los Angeles on account of the powerful 360-meter stations near by. The fine part of the set is that it is not only very selective, but clear as a crystal. I find your magazine is full of such prac- tical data as contained in this article, and want to thank you many times for all of it Such articles repeatedly appearing in Radio World will make it the best periodi- cal there is on radio. Very truly yours, Monticello, N. Y. Leslie E. Hicks. March 17, 1923. Error in Economy Radio Advertisement In our issue of March 10th was ad- vertised 2-Coil Mounts De Forest License $2.15. The Economy Radio Co., of 132 Nassau St., New York City, tell us that this price should be $2.35. FOOTE'S HAND-MADE TRIPLE-TEST CRYSTAL "Put. Its BMt Foot Foremct" Its euperseosltlre side Is up and ha* loudly recelred broadcasting. Guaranteed QfU (yotrr signals are strong). Look for th« "T" as the Distributors and Travellers Wanted. Liberal Cotnmhejlona. Lars* ealee. Quantity Production. Wire Territory desired. FOOTE MINERAL CO., Inc. Manufacturers and Wl»letal»r« 107 N. Hth St Philadelphia, Pa. "- Established l«7« National Radio Products Co. 509 Fifth Ave. New York City Radio Supplies of All Kinds to Suit Your Needs LISTEN IN ON— Stockton, CaL, or Seattle, Wash. ORIGINAL BLUE PRINTS of the Famous MAWHINNEY RECEIVING APPARATUS a, series of 7 blue print* giving In fall detail all the necessary Inform*- "ma. and method of construction, and eseembllng of the BBCXIVIMO Apparatus. This Is the 5 -tube reosMac aet that picked 5 etatloro In California, recently written about In Literary Digest and Badlo Globe. The Blue Prints tell you In a Tory simple and clear manner just how to con- struct a duplicate of MA WHIN - NET'S trans-oontlnental reoalr- lni sat. If yoc Sand $3.00 for A. S. MAWHINNEY Ml RIVERSIDE DRIVE Dept. » N«»y " 185 GREENWICH STREET NEW YORK. N. Western Electric V. T. 2. TUBES PHONES Stromberg- Carlson Berwick Supreme 2200-Ohms. AMPLIFYING TRANSFORMERS Adapted for 1J4 Vo»t Tube *"* Crown Triple Coil Mountings Pathe Loud Speaker— list Price, $22.00..... i »»•»• Bristol Loud Speaker Pathe Moulded Variometers and Couplers SEND MONEY-ORDER. INOUIOINR P08TABE— ALL SOODS GUARANTEES US FRESHMAN PRODUCTS Accurate and Dependable "MICON" TESTED MICA CONDENSERS Slr.e .00025 .0005 .001 .002 .0025 .005 .000 .01 Price $0.35 .85 .40 .40 .50 .73 1.00 1.50 ASSURE— Accuracy Nolaeleasneaa Clarity of Tone Constant Capacity VARIABLE RESISTANCE LEAK With .00023 mfd. Mi con Condenser * 1 A A Without *1 Cg, Combined eplaUU Condenser I I Clarifies Signals Eliminates Hissing- r • I Unbroken Range, Zero to Five Megohms .006 Micona and Variable Resistance Leaks especially adapted for use with new FlewelUng Super-Circuit At Your Dealers— Otherwise send purchase price and you will be supplied postpaid. CHAS. FRESHMAN CO. Inc., IK Seventh Ave. New York RADIO SPECIALS 52-Page Catalogue and Code Card Free with Erery Order CLAPP-EASTHAM RECEIVERS Type HR Regenerative Receiver— Mahogany Cabinets Type HZ Two-Stage Amplifier— Mahoaany Cabinets The Sets You Sea Advertised for $40 JS «2SH Nathaniel Baldwin "O" Headsets Nathaniel Baldwin "C" Units Frost 2000 aba doable Neadseti Frost 3000 ehai double Headsets Murdeek 2000 sen double Headsets Murdeik 3000 ohm double Headsets Murdeek 80 thm Reeelveri Double Headbands. Ms sll phones 8lnfle Headbandi. flts all shonee Double Phone Cores— six feet Single Phone Cords— elx feet....: 0. A. Phene Condensers. .001 mid 0. A. Srld Condensers. .0005 arid... Moulded Phone Condensers. .001 mfd Fesoe 3 plate Variable Condensers Fesee II Plate Variable Condensers Wsstwyre 3 Plate Variable Condensers ... Westwyre II Plate Variable Condensers.... Westwyro 23 Plate Variable Condensers.... Westwyre 43 Plate Variable Condensers. • • ■ Westwyre II Plate Var. Vernier Cond. Westwyre 23 Plate Var. Vernier Cend Westwyre 43 Plate Var. Vernier Cend Dials lurnlshed with all Var. Cond Na-Ald Coadenslto 3-lnsh Wale. Whltsll Moulded Sri-lneh Dials Whltall Red Coadenelts Sockets. ■ • • v k" - • Radio Corp. Pore. Soeketi lor 5-w. tubes. . . N.™d tSudenelt. Sejkets ffrW D-ll.... Whltall Moulded Rotors. 3 11-16 dlam Federsl 2-elreult Jasks .112.00 . 3.30 ,. 5.00 .. 6.00 , . 5.00 .. 5.S0 1.50 .75 .50 .50 .35 .20 .20 .50 1.50 . . 2.25 .. 2.25 . . 3.30 .. S.S0 . . 4.75 .. 5.25 5.75 .. 0.75 tips IVk V, small, in V, large. 5 V. regular .35 .50 .50 1.00 .75 .50 Frost Plugs, will take card tips Eveready "B" Batteries. 22' Eveready "B" Batteries. 22 Eve ready "B" Batteries, 45 8eneea "B" Batteries. 22 V. storage Red Seal Dry Cells, 114 V. for W O-ll Red Seal Sparkers. for W D- 1 1 tubes Acme Amplifying Transformers Radio Dors. U. V. 712 Amp. Transformers.. . . Radio Corp. U. V. 714 Radio Frog. Trans... Therdsrson Amplifying Transform ere Bradieystate — The perfect Rhea Paragon Rheostat Radio Corp. Rheostat PR 536 King Rheostat — A perfect Rhea Klag Vernier Rheostat Whltall 600 Mater VerUeeuptere Paragon Crystal Detectors with galena. Whltall double tested gales*, mounted Whltall double tested galena, unmtd W oedemata! for mounting crystals Switch Points, &i ft -Inch per dozen Swires steps .....par pair Whltsll 8wltohlerer, I ft -loop radios Copper 8eldcrlas Luge per del. Yellow Spaghetti far No. 14 wire— 3 ft Black Spaghetti for No. 14 wire— 3 ft Watch Cose Voltmeters far "B" Batteries Bristol Audlephene Weetlngheuee Vecareia S0.05 1.75 3.00 5.50 11.50 .40 1.00 4.50 7.00 6.50 4.00 1.05 1.50 3.00 1.00 1.50 2.75 1.00 .25 .23 .10 .10 .06 .30 .10 .15 .15 2.25 40.00 20.00 Sauare Buss Bar Wire, No. 14 Square and Turned, 2 ft length* SMS Disto Coils, the Perfect Reinarti Wound Coll, Special..... 1.75 Complete Stock of Atwater Kent Radio Apparatus— Complet* Stock of DubOior Concunaaar* Mail Orders filled tame day at received. THE WHITALL RADIO CO., SPRINGFIELD, MASS.

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RADIO WORLD IF YOU ARE INTERESTED IN RADIO YOU NEED THESE BOOKS RADIO BOOKS THAT HELP YOU Telling How to Operate a Radio Set— How to Build a Set— Principles of Vacuum Tubes and Other Radio Problems Radio Hook-Ups By M. B. SLEEPER A book thst five* you not only clear di» (rim* (or all kinds of telephone and tele graph receiving and transmitting acts, but simple descriptions of each circuit shown snd spaces for notes of results obtained. PRICE lie. Construction ef New TypeTran*- atlantic Receiving Sets Br M. B. SLEEPER There is a peculiar fascination about re- ceiving radio messages from the high- power stations of England, Franca, Ger- many, Russia and Italy, aa well aa these located in the Pacific Ocean and the Orien- tal countries. Several type* of simple re- ceiving sets for this purpose are described, with detectors snd amplifiers to accompany them. Suggestion* are also given for oper- ating relays snd reproducing the signal* o*j a phonograph. Schedule* of operating time for high-powered stations are given. In addition, there is some valuable data on home-made wavemeters for testing and ex- perimenting .PRICE He. Wireless Telegraphy and Tele- phony Simply Explained By ALFRED P. MORGAN One of the most complete and comprehen- sive treatises on the subject ever published. A study of its pa net will enable one to master all the details of the wireless trans- mission of messages. The author explains in simple language the theory and practice of wireless telegraphy and telephony. 154 pages, 156 engravings PRICE tlM Design Data for Radio Transmitter* (and Receivers By M. B. SLEEPER The only book that gives tables and data for designing, receiving and transmitting apparatus so that you need no knowledge of mathematics. It's the first book a be- ginner buys after he ha* learned the use of his phone receiver PRICE_JIc. Construction of Radiophone and Telegraph Receivers for Beginners Br M. B. SLEEPER The man who wants to feel the real thrill of accomplishment, and vat is net satisfied in the merely making uae of what ethers have done for him, builds his awn radio apparatus. Radio men can fallow the data in "Radio Phone and Telegraph Receiver*" with full confidence, because each piece of apparatus described was first made, tested and found efficient before the final design was accepted. Special receiver*, both crys- tal and audion, are shown in detail Regen- erative circuits as well a* audio and radio frequency amplifier* are described with clear photos, diagrams, and working draw- ings prepared especially far the novice and the man who wants to receive the radio telephone broadcast. A special feature I* the phonograph type radio set and the load speaker. Fully illustrated PRICE He. The Radio Experimenter's Hand- book By M. B. SLEEPER Throughout the preparation of this book, one purpose was kept in mind— Answer the Practical Questions of the "Novice," of the "Beginner/' and the more advanced "Stu- dent." This book will help in the selection or construction of simple apparatus for the transmission snd reception ef radio tele- graph and telephone signals. Ia the chap- ters on radio receivers the simplest crystal, the simple audion, and the regenerative types are described in quite some detail. The question of antennas, both for trans- mitting snd receiving, are taken up. A good many helpful suggestions sre given which will be of m enter considerable aid to the expert- 16 chapters. Fully illustrated. price n et The A B C of Vacuum Tubes Used in Radio Reception By t R LEWIS Assoc. 1. R, E, and Radio Inatractsr Written particularly (or the pais— whs "knows nothing about radio,'* but who would like to gain an understanding ad the elementary principle* of operation of vac- uum tubes and various circuits ia they are used for the reception of telegraph signals and radio- telephone i and speech. Illustrated... How to Make Commercial Type Radio Apparatus By M. I This book describes in marcsal types of spark snd telephone transmitting and telegraph and shale receiving equipment of aB hands. The earperimeater will be able *o get a world of idea* far the design and eoaatrac- tssn ef hi* next piece ef radio eqmpaneut frees the vary clear description* and that ■ clearly illustrated figures -PRICE Tse. Experimental Wireless Stations By P. E. EDBLMAN Telia bow to make apparatus to not only hear all telephoned and telegraphed radkt messages, but also how to equipment that works for I reasonable long distances. Then there is s host of now information mrlnded. The first and only book to give yea el the recent important radio imp mi assents, sons* of which have never before been penaashed. 392 pages, 1*7 iUnstratiasui PRICK UM Any of These Booka Sent Prepaid on Receipt of Price The 11 Books for $1».06, to One or Different Addresses address THE COLUMBIA PRINT ROOM 326, NO. 1493 BROADWAY, NEW YORK Digitized by Google

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