QST 1928-01: Vol 12 Iss 1

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JAN 2 2 7829 p.. DEVOTED AMATEUR RADIO PUBLISHED BY THE AMERICAN RADIO RELAY LEAGUE _— —_ aT ENTIRELY TO [! Promise To ABSORGD FROM My MNE@REST NEIGHBOR ALL THE Power 1 CaN CET— HONESTLY on OTHE Rw IS€ - THAT i wht FEED MY AUNT ENNA AT AL Cost - und Twice Nop HUG MY NE\OYBoR UNLESS IT Gives mone Food for AUNT ENNA RESotvEeD — That I wit”) PERCotATE FuLy On NOMA Load - THAT | SHALL NEVER GO WEST,- THAT (wi Even SE A TouCH Ha®p Baby RESOLVED - THAT § wit NEVER PUT AN UNWoRT} | PRomiISE To KEEP To THE RIGHT as Far AS POSSIBLE (RESoLYED - THAT twit KCEP My CHARGE “ITHIN THE BANDS ALLOTTED To THIS STATION Even AT COST OF DX a5 PosrAL CARDS — THar i witt KEEP MY Losses &S Low as THE SPIUT OF A 5S wayrER vr r lt On SYN DAT EVE ee WE PROMISE RESotvED m To Be ON oval J THAT ! jn a WAY in FEw —— oF THAT 1 Wit TELL HoVvAs OF NoHAM Hit $i6S HiTcH OUR ARE RO aw) Punt DESTINT TOA] Ipc WHEN HE 1S PosTAGE JUST AVODIBLE STAMP AND USES RAW LF bec \j) Pm :)). a ef ad oc) RO! : i" 822 ALWAYS Cook end NEVER LoaD ON THE an) To KEEP OBJECT TO A FEW THOUSAND TUuGE Flats MY HAND off EXTRA VOLTs ' of ZERO >| jasomane | JF ZR = THE HOUSE MINUS CURRENT ILLUMINATC THE SHaci+

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Radio Recepti bbs popular demand for the latest and most roved A C power receivers calls for the test development in A C tube construction, ingham AC tubes CX-326 and C-327 are ling in their performance and will bring A C power receiver up to its highest efficiency. that these two tubes are doing their duty ith other Cunningham tubes in your A C CUNNINGHAM, INC. CHICAGO SAN FRANCISCO With AC Power % Receivers Use Cunningham 1 C Tubes

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| Jhe Official Organ of the VOLUME XV JANUARY, 1928 NUMBER 1 ARRL ——— ~ | \ Editorials . . . . . ee.) ee oa ow celal ri Election Result es : ate . 2 i A General Purpose Device ; , ‘ : Howard Allan Chinn 12 ' The Amateur and the International Radiotelegraph Conference , K. B. Warner 15 This Amateur Phone Business ; . ‘ . P. C. Lackey and Dean Spencer 23 | Standard Frequency Transmission : . 7 25 | Municipal Ordinances on Radio Transmission Unlawful! A. L. Budlong 26 Grinding of Quartz Plates ° ‘ , ‘ , ‘ . E. G. Watts 27 Radio Frequency Chokes for ~eceivers . , Glenn H. Browning 31 New Station Licenses ‘ . . . . : , : ‘ . . . : . = A Portable Power Supply ‘ : , ‘ , . ‘ Rudolph Sturm 34 Horace A. Beale Jr. ‘ , ' : , . . ‘ . ; . ‘ . & The Helpful Audio Filter , ‘ ‘ ° ° . ’ ‘ . & Southeastern Division Florida Convention : ‘ . . ‘ ‘ ‘ 38 | nu3CAB ‘ ° ° . , : : " . : ; ‘ ‘ 39 \ Rotten Bunk ‘ : , , . . ; , The Old Man 42 Matching the Transmission Line to the Antenna ‘ : . Walter Van B. Roberts 3 The Unimportance of Short Leads ' . ‘ : ‘ ; ‘ ‘ L. W. Hatry 45 : Admiral Bullard Dies ‘ : , . ° ° . . ; . - 47 Experimenters’ Section Report : . ; « & Some Special Uses of the UX-222 , ; ; ; . Harold P. Westman 49 Re: The International Tests : , , ‘ : . ‘ 2 ‘ . ‘ - §1 IL A. R. U. News ‘ ‘ . ‘ 4 ‘ ° : : ‘ ; ‘ . 52 Calls Heard : ‘ i : ° ‘ ‘ ° ° ° ‘ . . - 53 Correspondence Department : . ° . . ° ° ° . . , . §4 Financial Statement ‘ ‘ ‘ m ‘ ‘ . ‘ ‘ ‘ . ; - 62 References and Book Review " ‘ . ‘ . ° ° ° . . R - 64 Hamads * ° . ‘ ° . . ° ° ° ° ° . . » QRAs . ‘ ‘ : ° ° ° ° , ' ‘ : ‘ . . ‘ - 9 ————$—————— — QST is published monthly by The American Radio Relay League, Inc., at Hartford. Conn., U. S. A. Official Organ of the A.R.R.L. and the International Amateur Radio Union Kenneth B. Warner (Secretary, A.R.R.L.), F. Cheyney Beekley. F Editor-in-Chief and Business Manager Managing Editor and Advertising Manager Robert S. Kruse, Harold P. Westman, David H. Houghton, echnical Editor Assistant Technical Editor Circulation Manager Subscription rate in United States and Possessions, Canada, and all countriesin the American Postal Union, $2.50 per vear postpaid. Single copies, 25 cents. Foreign countries notin American P stal Union, $3.00 per year, postpaid. Remittances should be by international postal or express money order or bank draft negotiable in the U. 8. and for an equivalent amout in U. S. funds. Entered as second-class matter May 29,1919, at the post office at Hartford, Connecticut, under the act of March 3, 1879. Accept- ance for mailing at special rate of postage provided for in section 1103, Act of October 3, 1917, authorized September 9, 1922 Additional entry as second-class matter, acceptable at srecial rate of postage provided for above, at Springfield, Mass., authorized Sevtember 17, 1924. Copyright 1927 by the American Radio Relay League. Ine. Title registered at United States Patent Office Member of the Radio Magazine Publishers’ Associat

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The American Radio Relay League The American Radio Relay League, Inc., is a non-commercial iation of radio amateurs, bonded for the promotion of interest in ateur radio communication and experimentation, for the relay- messages by radio, for the advancement of the radio art and the public welfare, for the representation of the radio amateur in cislative matters, and for the maintenance of fraternalism and a eh standard of conduct. It is an incorporated association without capital stock, chartered ler the laws of Connecticut. Its affairs are governed by a Board Directors, elected every two years by the general membership. The ers are elected or appointed by the Directors. The League is non- nercial and no one commercially engaged in the manufacture, sale ental of radio apparatus is eligible to membership on its board. “Of, by and for the amateur”, it numbers withiri its ranks prac- ’ every worth-while amateur in the world and has a history of sus achievement as the standard-bearer in amateur affairs. Inquiries regarding membership are solicited. A bona fide in- in amateur radio is the only essential qualification; ownership _transmitting station and knowledge of the code are not prere- ite. Correspondence should be addressed to the Secretary. Directors oe: sident Dakota Division Pacific Division 1 PERCY MAXIM C. M. JANSKY, JR. ALLEN H. BABCOCK r 2102, Dept. of Elec. Eng., U. of M., 65 Market St., 1, Conn. Minneapolis, Minn. Southern Pacifie Co., Sz ‘rancis Delta Division an Francisco 7 BENJ. F. PAINTER Reaneke Divi LT oTrR , > 424 He ilto Nat’ Re k Blde.. 10¢ Ione iriszion 7 tal deel SS W. TREDWAY GRAVELY ox 2465, Hudson Division Danville, Va. —_e DR. LAWRENCE J. DUNN tae a. wager 480 East 19th St., Rocky Mountain Divisic ie an Brooklyn, N. ¥. Ke@AUL M. SEGAL to, Ont Midwest Division c/o District Attorney PORTER H. QUINBY West Side Court Bldg., 1034 Planters’ Building, Denver, Colo. Division St. Louis, Mo. . Divies Cc. WOOD JFF . Southeasterr vision - anne — FF Vew England Division HARRY F. DOBRS Collere, Pa. DR. ELLIOTT A. WHITF c/o Dobbs & Wey Co., Dartmouth Colles Atlanta, Ga. Hanover, N. ; 4 Division Northwestern Division , West i Gulf Di B10 DE E. DARR K. W. WEINGARTEN FRANK M CORLETT ‘ Highland Park, 3219 No. 24th St., 2515 Catherine St., t, Mich Tacoma, Wash. Dallas, Tex. Officers H1rRAM Percy Maxim, Hartford,Conn. President . . . . . . CHaAs. H. STEwart, St. David’s, Pa. fo. . « « « « « KENNETH B. WARNER, Hartford, Conn. er. . . . . . . ARTHUR A. HEBERT, Hartford, Conn. cations Manager . . F. Epwarp Hanpy, Hartford, Conn. General Correspondence to Executive Headquarters, Hartford, Conn. a Co bw 6 : = =~ So =

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bottom of a heavy heart, we wrote a very black story of the very black outlook at the International Radiotelegraph Confer- ence. It will now be apparent, from the article elsewhere in this issue, that the story of our impending demise was greatly exag- gerated. The two accounts are not as much in conflict as might superficially appear, however. There was every justification for the December report; the outlook was at least that black; that we were unreasonably successful does not alter that fact. As this month’s article relates, we have received international recognition to an extent that a month ago seemed altogether impossible of happening, and the combination of hard work, a few smiles from the Fates, and the loyal backing of the United States Delega- tion has produced privileges for us m* _y times beyond what Europe wanted us to have and many times more than one could reasonably have expected from the situa- tion which confronted us about midway thru the Conference. We succeeded beyond the wildest dreams to which we were entitled at that time. At this writing, just at the close of the Conference, we are unable to state the offi- cial A.R.R.L. view of the Conference’s pro- visions for amateurs. Official A.R.R.L. views are made only by our Board of Direc- tors and our Executive Committee. To us at Headquarters, tho, it seems that these provisions offer us every assurance of a continued happy existence; and, in view of the many wild rumors which have been flit- ting about, it seems necessary that we Say so. The nations which ratify the Washington Convention are obliged to put it into effect by January 1, 1929. They may do so as much sooner than that as they desire, of course, provided such action does not conflict with the London Convention of 1912, which remains in effect, presumably, until that date. It is to be imagined that during the coming year our Federal Radio Commission will not make any assignments or regula- tions that will be found to conflict after the first of 1929 with the Washington Conven- tion. We sincerely trust, tho, that they will permit the amateur regulations of the United States to remain in status quo thru- out the year 1928, to give us the maximum time to contemplate the new situations which will confront us and to permit the amateur societies of the world ample time ie December QST on this page, from the EDITORIALS to make their plans for the new order of international codperation which will then be essential. URING the past month the members D of the A.R.R.L. Experimenters’ Sec- tion and the operators of A.R.R.L. Official Relay Stations have been requested by the Federal Radio Commission to conduct a survey of broadcast-reception conditions in their respective towns, particularly from the standpoint of heterodyne interference. The Commission wanted skilled observers, and neutral ones. We are proud of this opportunity to assist the Commission. Itis an honor. It is like- wise another example, for the world to see, of the utilitarian value of the American amateur. ROUBLE comes in bunches. The in- T ternational conference was not yet over when we were informed that the Fed- eral Radio Commission Was again experienc- ing a flood of complaints against interfer- ence to broadcast reception by amateurs. The situation is very serious. We do not know whether the trouble comes from in- creased listener-interest at the return of cold weather, or increased amateur activity for the same reason, but there is no doubt of the increase of complaints. So serious is the situation that we are informed that the Commission is contemplating an exten- sion of amateur quiet hours, when they are imposed, to six o’clock to midnight. This will be about as bad as sudden death to the amateur who experiences it. And so we are again waving the old Rettysnitch and we here and now call upon every amateur to take stock of his station and clean house. Do you interfere with your neighbors? If you do, you are very liable to have quiet hours from 6 to 12 hung unon you. It seems up to us, in- dividuaily, and for our individual preserva- tion, to take the necessary steps to avoid any such interference. If you don’t know whether you interfere or not, it is really up to you to find out by inquiry, and to remedy it if interference is occurring. Practically every case of BCL interference can be cured easily. It’s an annoying job, we know, but it seems that each one of us had better tackle it. If there’s trouble, take a look at the affected BCL set. Perhaps it’s ob- solete, or too tightly coupled to the antenna, or with too long an antenna. Probably the

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cured completely with a le from parts in the junk- the transmitter itself. Most tters are too tightly coupled too tight for best com- iency as well as too tight int of causing interference. e thing that may be done transmitter which will so se its interference as to ling. Most of the trouble ns comes from the keying, tual impact of keying or r ne of the wave as the power ff. Loosening the coupling s alot. But key filters or imize the effect of keying * antennas are often neces- There can be no dearth ese things—QST has had wi terial on them; so has the H \nd in particular all the ills to teur station is heir can be det t at the station b, the use of , ich as described on page 24 y issue. Every amateur sta- ve such a device and use it fre heck the quality of the sta- t ill quickly show up troubles ought to be done about it, the article referred to. little or no excuse for in- ( with modern-day BCLs. An on is not sharing as whole- ised to the view that if an complies with all the speci- license and still interferes, ’s hard luck. Next to the I.R chief news of this month is amateur owes it to him- and clear up any inter- station, or we won’t be 6-12 business. in its annual session, to League policies for another truct the officers how to licies. This Board is com- rs whose names and ad- t before the editorial page f OST. There is a director R.L. division in this country, Canada. In the determina- policies these directors pective territories. Mem- ws to express on A.R.R.L. communicate them now to Directors, in preparation I’ e A.R.R.L. Board of Direc- . y International Radiotele- W nference safely behind us, five years in which to will happen to us at OST JANUARY, 1923 the next conference and in which to ponder upon the motives behind the atti- tude of the European nations this year. The general purpose of that attitude was to come as close as possible to abolishing amateur radio, particularly international amateur contact. That this was not done is attributable to the very fine support given to the amateur cause by those liberally- disposed administrations which have en- couraged amateur radio and have found it, as it indubitably is, a great national asset. The European arguments against the amateur were numerous, diverse—and, for the most part, fallacious. It is in- teresting to examine them. During the eight weeks of the conference I cataloged the following: 1) Fear that amateurs will violate the state monopoly on communications, thus de- priving the state of revenue. Fear that a regulation prohibiting this violation would not suffice, that the very number of ama- teurs makes it impossible to police them adequately in this respect, and that the only safe control is to do away with them or make their operations so difficult tech- nically as to prevent them from accomplish- ing much. 2) The general denial of the right of any group to participate in communication other than governments and authorized commercial systems. Europe does not per- mit private enterprise to engage in com- munication, as is exemplified in this coun- try not only by amateurs but by our limit- ed commercial services, and it is an age-old policy to attempt to deny this privilege. 3) Fear of a general lack of control of amateurs, not only as to the nature of their communications as mentioned in the first item but with respect to technical features of their operating, and particularly a fear that they will cause interference with other services. 4) The general selfish desire of govern- ment and commercial interests to retain for themselves all useful wavelengths, and an unwillingness to allow privileges for non- government or non-commercial purposes. The value of an established international communicating service on a single short- wave channel, based on its potential earn- ing power, might be said to be a million dollars. Why give away hundreds of such channels to amateurs, who merely play and never really discover anything? One such commercial service is worth more‘than 25.,- 000 amateurs. This attitude was beautifui- ly summarized by the gentleman who rep- resented Canada in the frequency alloca- tions when he said that he did not think that amateurs should ever be given any wavelengths that are known to be useful for any commercial or government com- munication, and that he thought they as al fo th Wi

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JANUARY, 1928 should always be obliged to stay within ter- ritory which was regarded as completely useless for any commercial or government communication. 5) The delicate business of war talk. The astounding impression, based upon the fact that the technical representatives of the United States Delegation who spoke for that delegation in upholding the ama- teur were Army and Navy officers, that the American amateur is primarily an auxil- iary of the armed forces of the United States—and therefore to be discouraged. 6) Hysterical fear that the needs of new services in the short-wave field, such as shipping, aircraft, navies, etc., were about to create so great a congestion that it was impossible to spare any waves to amateurs even if it were thought otherwise desirable to do so. 7) Fear that amateur licenses might be granted to unscrupulous persons who would use such stations to undermine the security of the state, as by fostering revolution, spreading Red propaganda, etc. It is to be remembered that when amateur stations are permitted in such countries they are the only agencies of communication in the whole country which are not under the direct and absolute control of the state, particularly as regards censorship. There is hardly a government in Europe so stable that it does not have to take account of these possibilities. 8) General unwillingness to be bothered OST 11 by something that would make additional administrative work. The feeling that the United States Government is little short of insane in having encouraged amateur radio, and determination to avoid taking on that administrative work themselves. 9) Fear of the political power of ama- teurs if permitted to grow to large num- bers. Being completely unable to compre- hend that our own Government can and sincerely does regard us as a national asset, Europe has the idea that American ama- teurs must be forcing their Government to support them through political pressure and the power of their votes—and so the resolution to avoid that in their countries. It should be perfectly apparent to any informed North American amateur that the long experience of the governments of the United States and Canada, obtained in not only freely permitting but actually foster- ing amateur radio in this continent since the first days of wireless, offers abundant proof of the fallacy of these arguments. Fortunately the unfriendly European ad- ministrators of radio have in many cases returned home with greatly softened views of amateur radio, based upon a much better acquaintance with its nature than they ever had before. But these arguments open to view in some measures the difficulties that confronted the amateur representa- tives at Washington. x. B. W. Election Results OMINATIONS in the biennial elections for Director in six A.R.R.L. divisions were examined by the Executive Com- mittee on November Ist. In three of the divisions there was but one candidate and as a result, in accordance with our By- Laws, the following Directors have been declared re-elected to succeed themselves, for two-year terms which commence on January 1, 1928: Dr. E. C. Woodruff, Atlantic Division Prof. C. M. Jansky, Jr., Dakota Division Mr. Benj. F. Painter, Delta Division Mr. A. H. Keith Russell had no competitor as nominee for Canadian General Manager, and has similarly been declared re-elected for a two-year term. In the Pacific Division Mr. A. H. Babcock, the incumbent, and Lt. Col. Clair Foster were nominated. Col. Foster withdrew his name, leaving Mr. Babcock as the only nominee, and the latter was similarly de- clared re-elected for 1928-29 without bal- lotting by the membership. In the Midwest Division three candidates were nominated: Mr. Porter H. Quinby, the incumbent, and Messrs Ray E. Bolin and Frank J. Sadilek. The result, as ascer- tained by the Executive Committee on December 2nd, was as follows: Mr. OO REE ee 213 votes ee Pe EE ek cebiscdcddaees . 55 votes Mr. Quinby has therefore been declared re- elected for 1928-29. _In the Southeastern Division no nomina- tions were made and there is consequently no election. In accordance with the Con- stitution, Director Harry F. Dobbs remains in office until provision is made for a new election. K. B. W

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AC OST JANUARY, 1928 A General Purpose Device ined 15-to 2500-Meter Portable Receiver, Audio and Radio Oscillator, Amplifier and Wavemeter By Howard Allan Chinn* who for one reason or an- | it necessary or convenient abl receiver easily and for the man who e most possible use from pply of apparatus to move ne isual circuit own herewith will be found the amateur laboratory for only the cabinet depth 5 inches covering The panel the the ; article may be cf interest. se t lamentally a plug-in coil arrangement size viding a receiver ths from 15 to 2500 meters kiloeyeles) the se is t will b VIEW OF THE DEVICE eC e asa heterodyne oscil- as an audio oscillator, or as an ad- idio amplification for an denser unit show the general pane! 1 gives the circuit th the constants apparatus. f 65 uufd. maximum ¢ca- Laboratory. Technology, Cambridge, from the Col. of dia the A two section er is used for secondary rranged to permit the use Mass E. Mass H. pacity for short wave reception (below 200 meters) or both sections of 400 nufd. maxi- mum for the longer waves. The small sec- tion consists of three rotor and four stator plates, the rotor plates being cut (original- ly semi-circular, straight capacity line plates) to give approximately straight fre- quency line tuning for the first 70 of the 100 dial divisions. The plates were cut this shape merely for convenience in tuning the higher frequencies, the plates in the large section of the condenser being un- altered. Figure 2 shows the resulting shape of the plate. If one uses the usual straight capacity line plates only two rotor and three stator plates, arranged so that there are three active dielectric spaces, will be necessary to obtain the maximum capacity of 65 uwufd. The small section of the condenser provided a tuning range of about 1% to 1. That is to say, if the set tunes to 30 meters with a particular coil with the tuning condenser at a minimum capacity the maximum wave reached with that particular coil will be 45 meters. For the two sections combined a tuning range ratio of 3 to 1 is obtained. A miniature single-pole single-throw switch is mounted on the side of the dual section condenser (directly on the stator terminals) to provide selection of one or both sections. It is arranged with the switch arm connected to the large section and the switch jaw connected to the small section thus providing the minimum amount of extra hardware tied to the section of the tuning condenser that is used for the short wave reception. A National vernier dial is used for the tuning control, while the particular throttle condenser used was pro- vided with a geared vernier control. The radio frequency choke r.f.c. is a Sam- son helical wound choke and has been found very satisfactory on all the waves which the set covers. The use of a choke wound in this manner is strongly recommended in preference to the ordinary layer wound affair in a receiver of this nature where it is essential that the choke operate properly over a very wide band of frequencies. Be- cause of the construction of these chokes there is no pronounced resonance point and therefore no critical region within which the coils give non-uniform or undesired results. The amplifying transformer used is a high grade broadcast transformer (de-

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JANUARY, 1928 signed for broadcast reception) but one whose physical dimensions were such as to permit its being incorporated in a set of this limited size. The use of a good transformer is desirable because of the high amplification obtained on all kinds of ama- teur signals and the good quality broad- cast reception that results. To protect the tubes from mechanical injury and to reduce tube noises to a mini- mum, spring sockets were used. It is also advantageous to provide a means _ for damping the vibration of the detector tube, as for instance by stuffing some of the felt, the tubes are wrapped in when bought, around the detector. UX sockets are handy, in that, they permit the use of the different types of tubes that are now avail- able with UX bases. A 50-ohm rheostat is used to permit the use of any battery from 3 to 6 volts with either one or two tubes (of any of the usual types) in the sockets. 3attery connections are taken care of by means of a flexible multi-con- ductor cable. This was found to be more ss THE ARRANGEMENT OF THE PARTS Note in particular the trimmed rotor plates of the two-section variable condenser. with connecting was set up. fussing the receiver than time convenient wires each Phone tip jacks are used since they per- mit a quick and easy way of connecting the phones to the circuit and do not require a large amount of space back of the panel. The coil system is one that has been des- cribed many times in QST and has the desirable feature that the coils may be plugged in either way without affecting the operation of the set in the least. The plug spacing is the same as that found on the General Radio coil forms. The _ outside plugs and jacks (grid and filament) are spaced 115/16” and the inner plugs (plate and B plus) are %” apart. All manners of coils and coil forms may be mounted on the plug strip. Some of those which were OST 13 actually used are shown in one of the pho- tographs. The Samson coil forms will be found handy for those who wish to make a bank winding for the longer wave coils (above 1000 meters) because of the ends provided on the forms which gives one some- thing to wind “against” and does away with the unpleasant slipping of the first turn which one experiences when attempting a bank winding in ordinary tubing. WAVEMETER AND SIMILAR WORK A coil plug strip with binding posts or Fahnestock clips it may be used in place of the usual coil and by removing the tubes from the sockets we may connect to the secondary terminals and thereby obtain the Erste | @) ry _ | }~s u-o— 3 | +> : -_ | i | | ———— | F) | | | 4 4 +A DET C- AMD GR 6 8+ Be FIG. 1. THE CIRCUIT Cl Antenna coupling condenser. square, separated ”. C2 Secondary tuning condenser Small section of Cardwell dual condenser. 65 wufd. maximum. C3 Secondary tuning condenser Large section of Cardwell dual condenser. 335 wufd, maximum. ‘4 Sangamo grid condenser, 100 wufd. 5 Throttling condenser. 500 uufd. maximum. t1 Grid leak. 5 to 10 megohms R2 Filament Rheostat. 50 ohms RFC Samson type 125 radio frequency choke T Samson symphonic transformer. Two plates ' use of the secondary condenser for an ex- ternal circuit arrangement we may be working with. Also, by connecting to the proper terminals the throttle condenser can be used in other circuits. There is no reason why either one or both of these con- densers cannot be calibrated so as to furnish FIG, 2. SHAPE OF THE TRIMMED ROTOR PLATES condenser unit for laboratory require too great pre- a calibrated work that does not cision. It is also possible to plug-in a single coil across either one of the variable con-

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le provide an ordinary wavemeter whi t much larger than the usual one around amateur “shacks” and one e calibration will probably hold as v most of those in said shacks. If refers the heterodyne wavemeter the ls may be plugged-in and with the 1 condenser set at a given point 1d oscillation the set may be eali and it will be found that its cali n will hold quite well (Within 1% or 2 \ heterodyne with a rough cali- brat this nature will often be found ver} around the amateur laboratory. AN AUDIO AMPLIFIER If litional stage of amplification is need me purpose or other one mere- ly ] the binding post strip, places the tube in the socket, connects m& B Cc E F rU NED-COIL-AND-TICKLER COMBINATIONS No ’ ns need be given since everyone can easily ma ils te meet his own requirements. A—A made space-wound coil combination. BA ft mbination based on the Hammarlund celluloid rted windings. C—Lor basket weave coils. D—FH mb coils for long waves E—Co » a Samson coil form for intermediate ! being suited to wavelen the same forms also long-wa nanked windings. F—S windings on a General Radio bake- lite form to t r terminals and uses the last tubs sociated apparatus, thereby bta stage of good transformer ication. AUDIO OSCILLATOR as an audio oscillator, the dete removed from the socket, ter! 1 of Figure 1 is connected to and the detector B plus lead OST JANUARY, 1928 disconnected from the B battery and con- nected to the phone tip removed from terminal No. 1. The wave form of the resulting oscillation is, of course, far from sinusoidal but the thing will oscillate at an audio frequency and a source of noise is often useful. The frequency can be varied to some extent by adjustment of the throttle condenser (it now being a tuning condenser) or by variation of the plate lickler Tickler AAA A NWAW - o L__slaJaajojojt 0] pt .- A seme! 8 Use this arrangement if a source of variable voltage 18 averloble for use when vollage Source 13 of fixed valve ~ Permits very fine variation of balgnce voltage FIG. 3. THE SET AS A VACUUM-TUBE VOLT- METER A—Low reading milliammeter—not larger than 0-1 mil. R—Resistance 5 to 10 times meter resistance. R1—200 w potentiometer for coarse control R2—2 w potentiometer for fine control resistance of the tube which can most easily be accomplished by varying the filament temperature. It has been found that the tube usually must be run at a very low fila- ment voltage to obtain oscillation in the order of 1000 cycles with the particular transformer used in this set. Binding posts are provided on the panel for the antenna connection which may be to the grid through the small coupling con- denser, directly to the grid or through any capacity that may be inserted in series with the antenna external to the set. Direct connection to the grid is sometimes neces- sary for certain laboratory work and it was therefore thought desirable to provide the additional binding posts, which, incidentally, permits even the small coupling condenser to be used for other purposes. The ground is connected to the A battery plus terminal. By connecting the proper apparatus (meter, balancing resistances and _ bat- teries) as shown in Figure 3 between the tickler binding posts we have a vacuum tube voltmeter of the grid detection type. The uses of an instrument of this type in the laboratory are innumerable and need not be mentioned here. If one uses the set as shown as a thermionic voltmeter and wishes to measure the voltage across an open circuit (as far as d.c. is concerned) it will be necessary that the circuit be ar- ranged so that the grid leak goes from grid to filament instead of across the grid con- denser as shown in Figure 1. This change can be incorporated in the original circuit without affecting the operation of the set as a receiver.

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JANUARY, 1928 OST 1 or The Amateur and the International Radiotelegraph Conference By K. B. Warner, Secretary, A.R.R.L. and I.A.R.U. HE International Radiotelegraph Con- ference is over! The Washington Convention of 1927, signed on Novem- ber 25th, attests the eight weeks of strenuous work of 200 delegates, 178 special representatives, and uncounted function- aries, attachés and clerks, representing 55 countries and 23 do- minions and colonies. a day. We were joined at critical times by Mr. Maxim, president of the League and of the Union, under whose leadership we worked. We were gloriously backed and represented by the American Delegation and valiantly assisted from time to time by delegates from Canada, Italy, Australia and New Zealand. Most of the rest of the The London Conven- tion of 1912 is no more—a new order prevails. In it, for Highlights us. Recognition of amateur radio. world was against Even Canada, thru no fault of the estimable Command- the first time, the Amateur bands near 160, 80, 40, er Edwards, was radio amateur re- 20, 10 and 5 meters. against us when it ceives an_ interna- Amateurs of every country in the came to wavebands tional status and same bands. —of which more recognition as a fac- anon. tor in radio, the rules governing his conduct are set forth, and his rights and privileges are de- fined. Those priv- ileges in most re- spects are entirely adequate. We have achieved a great vic- tory. It is extremely difficult to compress within the confines of a single maga- zine article an ac- curate account of the eight busiest and most anxious weeks of one’s life, Ample bands for domestic work, ample for experimentation, probably enough for DX day work, uncomfort- ably restricted band for international night work. Power of amateur stations fixed by each nation. Each nation free to permit or pro- hibit amateurs as it desires; each na- tion free to withhold from amateurs any or all of the bands. International amateur message traffic forbidden except by special arrangements between nations. New system of amateur calls to indicate nationality, restoring inter- mediate “de” and abandoning “inter- national intermediates”’. effective Convention January 1, 1929. I have previously described how the conference was di- vided into commit- tees. Some matters affecting the ama- teur arose in most of the committees but most of our mat- ters were centered in the Technical Committee, presided over by the re- nowned and beloved General Ferrié of France. This com- mittee had _ three sub-committees, pre- sided over respect- ively by Professor A. E. Kennelly of weeks when the ulti- mate fate of the amateur hung momentarily by a thread. I do not know where to begin. I have written much about this conference in my editorials of the past several months, not only because it was the most important news of the day but also because it was a subject that had been occupying me almost exclusively dur- ing those months and I knew more about it than anything else. In those editoriais I have attempted to depict the gradual un- veiling of the Washington picture, and ! ask our readers to accept them as the back- ground for this account and let me go on from there. Vice-President Charles H. Stewart and I were in attendance during the entire eight weeks of this conference. We didn’t miss Harvard, of Kennel- ly-Heaviside Layer fame and a former A.R.R.L. Director; Mr. E. H. Shaughnessy, assistant chief engineer of the British Post Office; and Professor G. Vanni of Rome, who amongst other titles is president of the Italian Section of the I.A.R.U. The amateur matter first arose in Mr. Shaughnessy’s sub-committee when Great Britain’s proposal for amateurs was reached for examination, and the battle was on when Japan led off with the devilishly ingenious suggestion that all transmitting amateurs be obliged to use phantom an- tennas. Mr. W. D. Terrell, Chief of the Radio Division of the Department of Com- merce, stemmed the tide with a splendid address on behalf of the amateur, and served the first notice that the American Delega-

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ng its amateurs to get a fair a sub-sub-committee on the pointed, consisting of eleven fessor Mesny of France as Thru the kind efforts of the gation I was made a member tee, as a representative ) pause here and say that of amateur radio on the rth to-day is very largely he efforts of the United n. Amateurs in every rid are indebted to them rvation. There were liberally- ntatives from other countries, iptain Montefinale of Italy, wards of Canada, Mr. Brown and Mr. Gibbs from New course the amateur rep- re doing their very best. ild have been sunk if it nad American Delegation. Our tice from the first that they that the amateur be cared he opposition was equally in- lually it wore down a bit, and lt, as in all such things, se. But for one reason or the economic demand for ves and the fear that the iteurs in various directions slled, the bulk of the world posed to us. I shall say editorial page this month ns. This seems the proper ract the hymns of praise we editorial about the remark- and openmindedness of the as judged from a first y Ottawa. We regret that we pinion of them. The leaders they were the amateur’s nent, and unremittently and pursued us and hacked at tee. The British are said egotiators on earth. We from their standpoint they ++ they did a good job at Wash- part, we offer our apologies amateurs for our inference now their officials. back to that sub-sub-com- urs. It met the next day, rrell, Edwards, Brown and lelegates from their re- , on behalf of the amateur. hat there were going to have The British delegate at as Mr. F. W. Phillivs. as- >of the G.P.O. Mr. Phillips teurs too—had they not 1200 and? But of course the have to expect to be re- row territory. Mr. Phillips per all ready, as it seemed lelegate always did, and he OST JANUARY, 192: thereupon proposed that amateurs be as- signed a band in the vicinity of 150 meters and not more than six narrow bands, dis- tributed thruout the short-wave spectrum in harmonic relation and located, for ex- ample, at 109.33, 82.00, 54.66, 27.33, 13.66 and 6.83 meters. These unusual figures are, with the exception of the 82-meter wave, harmonics of 2750 ke. They were no strangers to us, for we knew that the British had a scheme for the division of short waves which provided a boundary between mobile and point-to-point services at 11 megacycles (about 27 meters) and that, using this as a starting point and, working in both direc- tions, they had arrived at this set of figures for us. We had other ideas, but this petite comité could do no actual allocating—it was merely making a recommendation, and of course we were in sympathy with the idea of harmonicly-related short-wave bands thruout the spectrum and this was but an example. The argument then hinged on the word “narrow”. The friends of the amateur did not want that restriction, as this committee at best was but recommend- ing, but Mr. Phillips (and he was not alone in it) stuck out for “narrow”, offering at one time to replace the term “narrow bands” with “bands not over 100 ke. wide”. Finally, by a vote of 6 to 5, the word “narrow” was retained. The meeting then decided to recommend that each nation remain free to determine the power of amateur stations; that amateur stations be under the obliga- tion of keeping their waves within their as- signed bands, stable, and free from har- monies; and that they sign their calls fre- quently. When the meeting adjourned it was freely predicted that we amateurs would eventually get 100-kc. bands at the British figures, and nothing more. This amateur report was accepted by Mr. Shaughnessy’s sub-committee and eventually by the whole committee under General Ferrié, and from there the recommendation for amateur waves went to the considera- tion of Professor Kennelly’s sub-committee, which dealt chiefly with the allocation of wave-bands. There a considerable delay ensued, for that committee was then work- ing on the allocation of waves down to 200 meters, in which we did not figure, and it was some weeks before the short waves were agreed to. In the meantime the question of the nature of communications to be permitted amateurs came up in the Committee on Gen- eral Regulations, where the chief United States representative was the Hon. Wallace H. White, jr., Congressman from Maine, father of the numerous White radio bills, and our friend for years. In _ practically every country outside of North America, the governments own and maintain all of the communication systems as a_ state monopoly, and they were all very insistent that this monopoly be protected against in-

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JANUARY, 1928 fringement by amateur messages. Many countries had made proposals about this, some of them amazingly drastic. France formulated a compromise between the pro- posals of Germany Great Britain and Switzerland which would confine amateur signals in every country to those relating to experiments under way and _ prohibit code, secret language, commercial language, “personal or actual information”, or in- formation for a third party. This was ter- OST tween private experimental stations of dif- ferent countries is forbidden, if the ad- ministration of one of the interested coun- tries has given notice of its opposition to this exchange. When this exchange is per- mitted the communications must, unless the interested countries have entered into other arrangements among themselves, be effected in plain language and limited to messages bearing upon the experiments and to re- marks of a personal character for which, by AMATEUR FREQUENCY BANDS assigned by The Washington Convention of 1927 : _ | Harmonic family Kilocycles [dui] Assignment. | Arges teisrs | iecior nose’ pesezersene| ‘pateus 1715-2000 | 265 ae 150 — 175 |149.9-174.8 | 1775 |168.92| Domestic 3500-4000 | 500 ” ” 75 - 85.7 | 74.96-85.66 | 3550 | 84.46 ” 7000-1300 | 300 | Amateur Exclusively | 411-42.9 | 41.07- 42.83 | T100 |42.23 |/*efpatignel 14,000-14,400 | 400 ” " 20.83-21.43 | 20.82-21.42 |14,200]21.11 -~ “ae 28000 -30,000 | 2000 |Amoteuré Experimenta!|10.00-10.T1 | 9.99 -10.71 |28,400 |10.56 | Experimental 56,000-60,000 | 4000 ” 5.00-5.36 |4.997-5.354 |56,800| 528 ” rible. This was an international confer- ence and its findings should not concern the domestic policies of any country; a country should be free to permit her amateurs to handle messages internally if she wishes; even internationally if both countries agree. It looked like the rest of the world wanted to prohibit our American amateur traffic just because they didn’t want their ama- teurs to handle messages. We rushed to Mr. White; he was already looking for us, to help. The British had a less obnoxious counter-proposal—they felt that the French proposal went too far, altho why we don’t know. We seized upon the British com- promise as a basis, but this text forbade any international messages under any circum- stances and even international contact be- tween amateurs if one of the countries con- cerned should object. Mr. White nego- tiated a further compromise for us, and by the next meeting had the agreement of the British, French and Germans. At that meeting he made a fine and able plea for the amateur and eventually we had the pleasure of seeing the compromise text adopted. Without his assistance we would again have been sunk, with useful message-traffic ab- solutely denied us. When the text finally came out of the Drafting Committee it read as follows: “The exchange of communications be- reason of their unimportance, recourse to the public telegraphic service might not be a consideration.” If this sounds hard, consider what it avoids! It is cruel to hear talk of an ad- ministration denying its amateurs the right to communicate internationally, but of course that has always been a nation’s privilege if it wanted to exercise it. As to the necessity for special arrangements be- tween countries before international traffic is permitted us, we’ve never had any par- ticular international traffic except with Canada, and that we feel sure can be ar- ranged. The amateurs of other countries have been prohibited from message handling anyway-—which is possibly proper enough in the case of actual messages whose handling actually denies revenue to the state—and so they lose nothing. The gen- eral freedom of action allowed under this provision I find quite gratifying, and ce) tainly infinitely superior to the original pro- posal which would prohibit every amateur from saying anything in the way of “per- sonal or actual information”. And now let us return to our wave- lengths, where the real story remains to be told. The sub-committee on allocations was an unwieldy body. Its work was of vital importance to everybody, so its meet-

Page 14

ded by the delegates of 78 representatives of a hun- terests. It had to conduct rmally, with recognition from nterpretation of remarks into sh, and its minutes had to paralyzing free speech. he long waves, then, it was as hopeless to attempt an » large a body, and so the ned while the various dele- to get together and agree entative program to be set ‘or discussion. Specially- tatives of the bigger powers nformally and discussed r the afternoon tea-cups ns at night. Gradually the is they came to be called, approaching an agree- of them would meet the f another country, reach an the three of them could progress to the point of tak- countries, until eventvall ement had been reached be- or ten leading powers. This entirely informally, out- onference, without official with no records kept and herefore able to speak free- so were thus consumed, ymmittee reconvened and restions. By that time it ment of the leading coun- an admirabie basis for of course altered in the ion but eventually bein negotiated over the tea- waves down to 200 meters letermined to thod for a preliminary pon 1t was dé the short-waves, and the sub- adjourned to await a Our anxiety then can be We had seen the long-wave tiated informally, the only with many people unable n the original formulation, that plan subsequently le alteration. The short- as admittedly much more lifficult that the possibility would be no agreement at OST JANUARY, 1928 all. But if one were eventually secured, what chance would there be to get altera- tions in it if we didn’t like it? About zero, we figured. It was therefore a tremendous relief when I was personally invited to participate in the short-wave discussions, to represent the amateurs. Altho elated that I was to be a tea-cupper myself, we had our grief even then, for they informed us that the room where the get- togethers were to be held was so small that there was room for but one amateur rep- resentative. And so we had to break up the old Stewart-Warner firm and I went alone. [ cannot tell you amateurs of my emotions as I sat for days in those meetings, the only amateur representative. I felt that my re- sponsibility was a very heavy one. The fate of the amateur world rested largely on how I conducted myself. I had loyal friends in the United States representatives present, and an occasional one from another country, but the rest of the world was frankly against me. Would I be able to put it over, even with all the help of powerful friends? Would I be able to tell our story convinc- ingly enough to get our modest requests from an assemblage which was determined not to give it to me? I had no one with whom to consult during the meetings; I could only keep my wits about me and do my best. But between meetings Mr. Stewart and I had long sessions of our own, analyzing the work to date and altering our plans as the situation changed, and then | would go back to another meeting to carry on. It is necessary here to digress a moment to explain the informal American organiza- tion which represented this country in these wave-length discussions. All technical mat- ters of the American delegation were under the direction of Major General Charles McK. Saltzman, Chief Signal Officer of the Army. General Saltzman is a loyal friend of the amateur, and he proved it thruout the con- ference. Amongst the technical advisers attached to his staff for the conference were Lieutenant Colonel Joseph O. Mauborene, for the last several years in charge of re- search and development for the Signal Corps but now on duty at the Chief’s Office; Cap- tain S. C. Hooper, in charge of the Radio Section of the Bureau of Engineering, U. S. Navy; and Lieutenant Commander T. A. M. Craven, U. S. N., who was recalled from sea for duty at the conference on behalf of the Navy Department because of a previous- ly demonstrated peculiar aptitude for this kind of work. These three technical ad- visers represented the United States in the wave-length negotiations. There was the real meat of the whole problem, and there was where their insistence on behalf of their Government that amateurs be provided for was really effective. We amateurs have much for which to be grateful to them, for they saved the day for us. Captain Hooper _—" ont ath Oe 4h wt 2b & at st otf '_ a

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JANUARY, 1928 presided at all the informal meetings of the “tea-cuppers”. Commander Craven con- ducted the actual negotiations. In fact, the structure of wave-length allocations finally arrived at is largely his handiwork. This young Naval officer has made an enduring name for himself. It may be said that he is personally responsible for the successful negotiating of the wave-length agreements embodied in the Washington Convention of 1927. What a monument to have to one’s credit! The conference has praised him for it. I sing his praises too, for he was the staunch and clever friend of the amateur and in large measure we owe what we got from the conference to his skill and per- severance. These three officers let no op- portunity go by to stand up for us. If we did not get all we want, it only shows the difficulty of the task and how hopeless we would have been without their help. I want to tell you amateurs that our friendly bonds with the Army and Navy have paid the richest possible dividends! But I must get on with the tea-cupping. It was a most difficult task. There were about twenty-five people present at most of the meetings, representing eight leading countries and a number of special interests. Six meetings were held, stretching over eight days. Gradually an agreement began to take form. There were endless argu- ments between mobile and point-to-point, conflicts with expensive beam stations, and what not. It was really very difficult and only a splendid effort to secure agreement by mutual compromise made the result pos- sible. Amateurs were left out while the preliminary chopping between mobile and point-to-point was made, but with pointed insistence by the U. S. delegates that the meeting should return later and fit the ama- teur into the picture. I was on needles and pins for days, watching this part of the program in which I did not participate, in- wardly pulling for a division which would put point-to-point bands at the places where I wanted to see amateur bands. The United States wanted the same thing, and even- tually the division was made along lines that made that possible. In the meanwhile the upper amateur band, to be “in the vicinity of 150 meters’, was located as from 150 to 175 meters. Higher territory seemed impossible; it had already been determined to give 175 to 200 to mobile exclusively, when the long waves were discussed; didn’t much care; that seemed ample for our needs in an upper band, even if it were non- exclusive (as indeed it already is in this country). Besides, I was holding my fire for the short waves. At last they got thru the table, down to 13 meters. Then they started on some narrow bands for short-wave broadcasting but couldn’t agree and decided to leave that for a still smaller group to discuss. At last OST 19 the amateur question! I took another reef in my belt and prepared for action. Mr. Shaughnessy led off. The table as agreed at that time provided certain ex- clusive bands for point-to-point, some more exclusive bands for mobile, and some nar- row shared bands. His proposal was that the amateurs share a small part of the al- ready shared bands. I had horrible visions of a senseless selection of amateur bands without harmonic relation and filled with mobile interference. Some days previous we had prepared and circulated a paper con- taining a suggestion for the amateur bands, proposing that they be centered at 20, 40, 80 and 160 meters as locations where our opera- tions of the last several years had un- doubtedly served to keep them clearer of established commercial services than any other locations; and, instead of “narrow” exclusive bands, urging moderately wide “N.G.P.” bands, that is, bands reserved for stations not open tq general public corres- pondence, such as government stations, ama- teurs, etc., from which bands amateur sta- tions might be provided. The idea was that this would provide sufficient flexibility to make wider bands possible in countries hav- ing many amateurs, yet leaving a nation free to assign her amateurs but small bands if the number of amateurs was small or the administration hard-boiled. I countered Mr. Shaughnessy with this proposal, and Commander Craven backed me up with the request from the U. S. Delegation for more definite amateur bands. But nobody else liked the N.G.P. idea, it seemed. The situa- tion instantly was serious, for with this idea of flexibility lost we would be confronted with fixed bands which would inevitably be narrow—the maximum to which interna- tional assent could be got. Then Captain Gino Montefinale, of the Royal Italian Navy, the commandant at IDO, proposed a counter scheme, suggesting amateur bands centered at my figures and of variable width, as each administration desired, but not exceeding certain maxima, and these maxima were the same as the proposed widths of my N.G.P. bands. Captain Montefinale was a fine friend of the amateurs thruout these meet- ings, and in fact absolutely the only one we had outside of the American delegation, for even Canada worked steadfastly against us for all her delegate was worth. The ama- teurs of Rome should give Captain Monte- finale a dinner—his assistance was most ap- preciated. But nearly everybody objected to his scheme the same as they had to mine, and the battle waged on thru anxious mo- ments. France would accept if the bands avoided the mobile waves. Mr. Shaugh- nessy objected that our proposed waves would hit into the center of the point-to- point bands and again demanded that ama- teurs be in the shared bands, with talk of 800 ke. total for us, in which he was sup- ported by Germany. I objected again,

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20) OST me by all the mobile people, I U. S. and Japanese navies. An ve sold them on 20-40-80! I tl endously important, not be- vere our American waves but cupancy of them had made likely to conflict with estab- ial services than any other lk light have named—and future [ was dead right in that. Mr sy would agree if the ama- narrow as the sub-sub-com- mmended, and came from the sint-to-point bands, and he near 18% meters, 200 ke. 100 ke. near 75. This was a ession for him, but fixed widths were hopeless and I urging my flexible scheme. \ n and the KBW-Montefinale and the general idea of proposal voted. France, d against both, thinking my is and Mr. Shaughnessy’s Only Italy and the United : rted us at this juncture. Then found that no agreement readily on the width of ds—this meeting was still this subject was referred ll group, more or less volun- going to meet that after- id some narrow bands for asting, and the meeting f the situation that noon. d the location of our bands ithem. The flexible N.G.P. carded, and rigid amateur dimensions were proposed. that we were going to get the international waves, nportant than ever to work ry in the national waves fforded by a rigid family of lated bands. At once we de- ndon this idea and to nego- band separately, as we found | to ask for wider non- ry in the 80-band rather y 100 ke. that would be true harmonic plan. assembly which met that ide upon the broadcasting ands. “Sub-teacuppers” is for us, I suppose. There f us: Col. Mauborgne, Com- Major W. Arthur Steel of n der Pol, of the Netherlands, e European broadcasters, E. Rickard, representing the tations, Capt. H. Abraham, epresenting Telefunken, and was the only actual govern- present and, aside from Col. Commander Craven, the even represent a govern- JANUARY, 1928 ment. But this group was constituted for this purpose, and away we went. I kept out while the broadcast bands were being settled, and Dr. Van der Poi laid off when we got to the amateur matter. At last the moment had arrived! Now or never! But what an odd group to say what the amateur should have! It was a good enough group to decide the broadcasting question but it was only by chance that it was given the additional job of recommending the ama- teur bands. I had explained to Commander Craven my idea for wider non-exclusive territory in the 80-band, to which he readily assented, and in short order he personally sold the meet- ing on 3500 to 4000 ke. non-exclusively for amateurs, our present American assign- ment. This was immensely better than I had hoped for; it assured us “a place to live”, from which to sally forth to narrow international bands if we got short-changed below, as seemed unavoidable. Non- exclusive was quite all right, for we have always shared that band with army mobile, naval aircraft and naval vessels working naval aircraft, without trouble. Then we tackled 20, for which the proposal was 400 ke. There wasn’t a chance to get any more. It really seemed about sufficient for the rather limited amount of day-light work which we amateurs do. We have had 2000 ke. there not because we needed it but be- cause that width was dictated as the har- monic of our 40-band in defiance of the in- verse economic value of the respective bands. I also found amateur occupancy of the 20- band entirely insufficient to justify a demand for any more, to say nothing of needing to hold my steam for the 40-band. The 20- band was located between 14,000 and 14,400 ke., those figures escaping the established services of the gentlemen present. And then we tackled 40, the real rub. That was our international night band, the place where we all assemble from every nation for our international communications. Next to our national bands, territory there was our most important need. I was asking for 800 kc. there and our own government was quite in agreement, as they had planned 7000-8000 ke. for us on the N.G.P. basis. But there was never a chance for it—it was too much more than the British idea of 100 ke. or Mr. Shaughnessy’s generous 200 ke. The meet- ing attempted to find a place in the 7000- region where no commercial services were already in existence, as indicated by lists available. A start was made at 7000 kc. but only 200 ke. were available before a snag was encountered in the form of an existing German station. I didn’t know, and don’t know to this day, just what that had to do with it, but the idea was to get unanimous agreement of all the other interests to what was given us amateurs, and here the Tele- funken representative couldn’t agree be- cause he had a station there! He might

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“v id ‘a 10 dd id LS re in 0 re ir. t- 0- re ts cc. ag ne n’t do us at le- e- JANUARY, 1928 have been out-voted here but the main tea- cuppers would have supported him the next day. Another location was tried but Major Steel objected, claiming that Canada had a large number of stations established in that 7000-8000 band which has been assigned to amateurs in Canada for four years. In fact Major Steel steadfastly refused to give his agreement to any large amateur assignment in that area, and he hurt us a great deal. He had been appointed by his delegation to represent them thru all the allocation mat- ters. In these matters he sided most of the time with the European viewpoint, particu- larly the British, and but rarely with the American. It seems so strange, for surely Canada’s radio destiny is the same as that of the United States, not Europe’s—and that has been Canada’s policy for years. But the Major’s idea on amateurs was at least as bad as that of any European and he worked against us steadily. It will be a disappointment to Canadian amateurs to know that their representative did not up- hold any of the wsual policies of their gov- ernment respecting amateurs, but instead was quite of the opinion that amateurs should not be permitted to occupy useful communicating waves, and that he did all he could to keep us out of them. He joined the Telefunken agent in refusing to agree to anything as rash as 400 ke. for amateurs in the 40-band. Eventually Capt. Abraham agreed to move one of his stations and a 225 ke. band from 7000 to 7225 ke. was de- termined upon. It is interesting to note that this band was clear of any established commercial or government stations, and that its limits are defined by the maximum width to which Capt. Abraham and Major Steel would agree in consideration of their estab- lished stations! Our band was no more than the Telefunken agent would agree to! Nor could it be widened or moved because of Major Steel. It seems so odd that such considerations as these should have entered into the making of the recommendations of this meeting, yet this little group had been appointed to make a recommendation and of course this was what they were going to hold out for, and the best efforts of our American people were unable to change it. I couldn’t assent to these figures, and didn’t, but that didn’t alter the maximum to which the meeting could get agreement. Then the 10- and 5-meter bands were easily fitted into the picture, and we adjourned. The next morning the sub-teacuppers re- ported to the teacuppers and, strange to re- late, the only objection was from me! I was then holding out for 400 ke. at 40 in- stead of 225. By then I was prepared to recommend that we agree to the rest of the table but I thot we needed and rated more at 40 and I could see no good reason why it couldn’t be spared to us. Capt. Hooper, as chairman, supported me, but the British OST 21 claimed that they had important services there and that it was out of the question. Capt. Abraham then said that the preceding day it had seemed too difficult to shift exist- ing stations but that he would now com- promise with 300 ke.—7000 to 7300. Mr. Shaughnessy would shift his stations too and agree. It meant 75 ke. more and it became apparent that it was the very maxi- mum to which agreement could be got. But the fireworks weren’t quite over, for Mr. Shaughnessy objected to our 10-meter and 5-meter bands being marked exclusively amateur, saying that we might succeed in developing the 10-meter band into useful communicating waves and that in that event we shouldn’t be permitted any such exclusive possession of valuable waves. It was at length determined to compromise by open- ing them to “amateur and experimental”. Altho a small point, it illustrates the deter- mination with which the British pursued us at every stage of the game. And finally everybody agreed upon these figures for us amateurs and the whole report was ac- cepted. From that time on there was never a chance for any alteration in the figures. These meetings were strictly informal and not officially binding upon a soul present, much less upon the interests they rep- resented. But it was considered that an agreement had been reached and there was an unspoken pledge to stand by the agree- ments. This pledge was at once the weak- ness and the strength of our position for, altho it made impossible any attempts to increase our 40-band allocation, it insured strong backing for the preservation of the table against any who might attack it. It shortly became apparent that it was con- sidered that our United States delegation, by having participated in the negotiations, was bound to support these allocations for amateurs, and in fact it was considered that we had accepted them too and for the same reason. Careful sifting of the situation showed that there wasn’t a chance to get any agreement on anything greater. Besides, these figures really weren’t half bad. To make a very long story decently short, the tea-cuppers laid their work before Prof. Kennelly’s sub-committee on allocations as a basis for discussion. It was hopped upon by various people, particularly folks who wanted to question the great width of the amateur assignments. Here Prof. Ken- nelly roundly defended us, and the very fact that it was considered that an agreement

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the sub-committee th it there it was adopted just as ng table. nple for irs in every country. d amongst the major powers | to stand their ground and le short-wave table against a result, it was easily without adopted a few Comnit- Plenary similarly the Technical reached the great applause, for it was perfectly mountainous piece een accomplished and that it ver good job. This was the tional conference ever held of the world, with nearly represented, and they had .greed upon the partition of ym 30,000 meters to zero. ie story of the determination wavelengths in the conven- Jur wave-bands are shown in If the reader feels satisfactory deal, give the Inited States Delegation. If em enough, they were the best got in the face of united ut I feel that we must we have been most suc- have received a great deal of the world wanted us to single exception of our 40- believe we have all that we ‘or our international night and we shall have to devise perhaps new apparatus, and have to employ a greater ernational coéperation than jut all of these things are and we have always gloried for licking a new job. time in succeeding months new problems confronting us for their solution. The con- ‘t go into effect until the there will be time to adjust new situations. These new should be considered every country but this country will find a way. phasized, tho, that no nation ands tself to permit the existence at is strictly its own busi- rtunately the conference rtunity to insure the exist- Nor is rated to put the entire width at the disposal of her ama- few of them will; the bands OsT JANUARY, 1928 are merely those which nations have inter- nationally agreed are to be used for ama- teurs in countries which so wish. We may feel sure, though, that we have gone a long way towards selling the amateur to the administrations of the different countries, and now that there is international agree- ment on amateur territory and a nation may know that it is not stepping on the toes of another in giving certain waves to its amateurs, we may hope that there will be a much greater disposition in foreign coun- tries to treat the amateur liberally. Be- lieve us, they have certainly heard about the amateur at Washington! And now, rapidly, some other amateur matters. Each administration will fix the maximum power of its amateur stations. The stations must be licensed and the ad- ministrations must assure themselves of the proficiency of the operators. The sta- tions must comply with all the general re- quirements of the regulations, particularly as to observance of wave-length, stability of wave and freedom from harmonics. They must sign their calls at frequent intervals. The calls are to be assigned from the same “national blocks” as the calls of commer- cial stations, consisting of the one or two initial letters that indicate nationality in such calls, a single figure, and not more than three letters. These calls will be used in connection with the intermediate “de”. Thus the governments do away with the necessity for our international intermediates—be- ginning in 1929. The other important ama- teur question was the nature of our com- munications, and that I have reported pre- viously. In the near future, probably the next issue, QST will print pertinent extracts from the Washington Convention applying to the amateur. We shall advise where and how the document may be obtained as soon as it is available. The coming year un- doubtedly will see in QST much discussion and much new material and many new de- cisions based upon our new conditions, as we analyze them and learn their possi- bilities. It has been a great two months, the hardest but the most interesting in my life. It has been a wonderful experience. I am proud that we may call it successful. The unyielding world has yielded, and we ama- teurs are safely written up in the greatest communications document of the age, the Washington Convention of 1927. ge gr (p loo on of Ho “as t

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2 e- ne vO in an in us ty C= a- m- e- xt ng nd on in- on le- as si- she fe. am ‘he 1a- est the JANUARY, 1928 OST This Amateur Phone Business By P. C. Lackey* MATEUR radio phones have prob- ably been the cause of more bad feeling under the head of, “Grief for the Transmitting Amateur” than any other thing he has ever been attempted. After operating an amateur phone for some years we have arrived at the con- clusion that most of the bad feeling has been justified. The moral is, “if you are going to use phones use a rig which will not disgrace the whole A.R.R.L. to say nothing of your own particular station.” We plead guilty to “getting quite a kick out of” operating our radio phone sets. The idea seems to prevail that no one ex- cept a “ham”, a “lid” or a rank beginner even fools with phone. Unfortunately this is true to some extent but there are old timers who enjoy “chewing the rag” by phone. These men are not DX crazy, they know they have no chance to get a WAC certificate with a 15-watt phone set but they can get the RCC certificate easily and they find it enjoyable to handle traffic with people who have something to say besides “VY GLD QSO CUL 73”, even though they are only a hundred miles away, which for that matter is not always the limit for a good phone of low power. We still remember when we started our first phone set. Says Lackey to Spencer: “Where do you get the dope on a phone set?” “Ballantine,” So we got it down and read it. It is great stuff; every amateur should have it (phone or c.w.) but a lot of them don’t. “Now, how about QST?” says Spencer. So we got down the complete volumes and looked them over. Plenty of dope on c.w. on receivers and on everything else and all of it FB but almost nothing about phone.’ How come? We decided that QST was “agin” amateur phone and were all heated says Spencer. *5AJ, Blanchard, Okla. 75JU, 1302 Division St., Sulphur, Okla. 1. It is my sincere opinion that the operation of a phone should really not be permitted except to those who have demonstrated the ability to operate atisfactorily a c.w. set with d.c. plate supply. How many would pass that test?—-Tech. Ed. 2. This has purposely been so because at HQ. we are convinced that phone operation should be touched only by those able to create a steady carrier wave which will not be wabbled whenever the modulator goes into action and thereby spread all over the tuner If a change in plate voltage changes the wavelength the oscillator is not good for telephony for that matter for use with a.c. and a _ key. —Tech. Ed. and Dean Spencery up and ready to grab up a sheet of asbestos and write a letter on it when we saw that the League had persuaded the new radio commission that the amateur should retain the 150- to 175-meter band. Right on top of that we see a “stray” saying that QST will consider some articles on amateur phone. “Let’s write one,” says Spencer. “Nix!’’, says Lackey. “Who in Sam Hill told you we could write an article?” “Well,” says Spencer, “we can tell them about our experiences and they might print it if someone doesn’t take a notion to write a real article.” So here we are. The first thing is to build the oscillator and as QST has often remarked, “the cir- cuit you like the best is the best for you.” Without even considering the modulation system, first get the oscillator going on the desired wavelength. In this case it must be one of the bands alloted to amateur phone and must emphatically not be in the 40-meter band. We believe the 170- to 180-meter band to be the most satisfactory as the very essential “DC tone” can be ob- tained much more easily in that region than on 84 meters§. Our sets accordingly work in the 170- to 180-meter region though if one insists on hunting for trouble they can euSily enough be adapted to 84-meter work by simply changing the oscillator in- ductance.* For no good reason, other than the fact that we “like it best”, we use the Hartley circuit with shunt feed. Since this cir- cuit has been thoroughly discussed‘ we will say no more about it but refer you to the diagram. 8. The staff is selective fading the favorable.—Tech. Ed. 4. Before decent modulation can be the oscillator must be adjusted so that the antenna current will be proportional to the plate voltage. This can be done with the grid and plate clips and the grid leak and should go before any thought of modulation. Better put the modulator off for a few weeks, or altogether, if you can’t get this adjust- ment. See the following reference in QST April, of the opinion that because of 80-meter band is much less hoped for, 1926, page 8; May, 1926, page 17: also page 43; June 3, 1926, page 29; July 1926, page 8, also page 29; August, 1926, page 19; Nov., 1926, page 22: December, 1926, page 9; January, 1927, page 14 and page 27; February, 1927, page 9; March 1927, column 2, page 17, and page 33 the same issue. se sure to read “Some Light On Transmitting Tuning,” July, 1927, page 24. None of the crystal control sets referred to operate in the 175-meter region but the necessary modification is obviously to multiply the constants all the way through by 2 or 4.—Tech. Ed. $ This article was turned in before the 80-meter band was closed to phone operation. All information is applicable to the new 20-meter phone band Editor.

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ATOR ADJUSTMENT the methods described in pre- QST to determine what kind have, then juggle the filter lator adjustments until you lutely pure de. whistle. stay at the bottom of QST OST JANUARY, 1928 absent. This is primarily a phone set, the switch causes losses, and the gain from put- ting four tubes in parallel is usually not very much worthwhile. When the set is used for CW the key is plugged into the closed circuit jack in the “center tap”. This jack is indicated by “X” in the diagram. A glance at the diagram will show that a microphone, micro- phone battery, microphone trans- former, two additional r.f. chokes and an iron core audio choke (also called “modulation choke’) are needed to operate the two modu lator tubes. Microphone trans formers appear to be scarce and a reasonably satisfactory one can be built from an audio transform- er. Remove the leads from the binding post, tagging them as you AFc eee wicmohone Transformer Microtone TRANSMITTER DIAGRAM that it is perfectly rH point out + phone should work best. The counterpoise is a 5-wire fan 90 feet No. 6 bare copper on 5-inch tube, tapped each 6 bare copper on 7” e hundred turns No. 26 on 3” tube ns No. 26 on 1” tube. | audio frequency Ballantine's design page 151. 00 chms other suitable variable resistance. jack for cutting in telegraph key. nine condenser, 500 pufd. or larger. rser 200 unufd. or thereabouts. condenser, 200 uufd, or thereabouts. by-pass condensers, 600 uufd receiving condensers, tmeter. is highly important. Don’t statement as to have repeatedly report- signal as d.c. when it had of 60-cycle modulation and of the people reporting 9XL nal d.ec. although it has per- ent high frequency modula- modulation as is used by stations! Tech. Ed.) Past have given the information ; ’ fellow’s People everything from a motor a rock crusher! If you th that information (or Bal- do a little careful work you difficulty. MODULATION tice that the usual D.P.D.T. hrowing all tubes in parallel is normal as to od results depend on careful adjustment, not The constants given are for 175-meter region The antenna happens awe 60 feet long, 410 feet up and L connected, but tube, tapped each turn. Mount on grid terminal ‘ choke or modulation choke. ries. Made as described or used R.C.A.—UP415 do so, carefully remove the primary { winding and replace it with as much No. 26 or 28 wire as pos- sible. Then reassemble the trans- former and bring the leads out to the proper terminals. The plate reactor can be made in the same manner, if necessary, ex- cept that both primary and second- ary windings of the audio trans- former should be removed and re placed with one winding of No, 26 wire. This plate reactor really should have an inductance of 6 henries at least, for the UX- 210 tubes. A good speech amplifier between the microphone transformer and the modulator tube is worth while. A stage of push-pull amplification works very well at 5AJ. The thing can be supplied with the same A, B and C voltages used on the transmitter but this is compli- ‘ated and we advise separate sup- ply. While speaking of the sup- ply a.c. may be used on the modu- lator and oscillator 1nlaments but the center tap must be right and don’t forget that the plate supply must be pure d.c. Soov - 6. ¢ Filtered / long. = or 28 ADJUSTMENT First, adjust the oscillator with the modulator tubes removed and don’t go a step further until this adjustment is per- 5. Awful quality will result if the core of the transformer becomes saturated or the microphone fries. Keep the microphone voltage down. If the reactor is too small little modulation will result Tech Ed 6. Be sure to use a voltmeter and to make th adjustment indicated in note 4 If that adjustment is not made you are simply clawing around in th dark. Don’t try to see how big the antenna current can be made or you will absolutely destroy the straicht line ratio between plate voltage and antenna current.—Tech. Ed ne ex of be oe ca Ww se. Re in po an mi fe! bu St 9V ate sta gre) mi an Th La tio tio reg ope by his on to wh “he que of

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he ut- 101 sec sed nis rill YOo- .eCS iso re lu 18 nd an m- he ou as S- 1S- to in d- 1S- 6 Ol er he he he me he It h mt ‘mt he JANUARY, 1928 fect." Now insert the modulator tubes, connect a 45-volt C battery, close the micro- phone switch and put on the plate power. If the modulator tubes try to burn up add more C battery before going on. We have used as much as 135 volts for UX-210 tubes. When these tubes run at a decent tempera- ture run a test with one of those very rare amateurs who really knows what decent modulation is. Then make final adjust- ments for best results. We acknowledge freely that there is nothing new in the set we have described but we hope that our comments as to the extreme importance of adjustment may be of some benefit. Such adjustment having been made, the transmitters at 5AJ and 5JU have given very gratifying results. At 80 miles they have permitted communi- cation by voice every afternoon for three weeks. This has been during the static season. Naturally, these transmitters have gathered in no extreme distance records (for that we have a 200-watt c.w. rig) but in four years of operation we have had re- ports from both coasts, from some 33 states and three Canadian Provinces. As we remarked at the beginning we get much satisfaction from talking with our fellows and we really believe that the “amateur spirit’ exists among the phone bugs. Standard Frequency Transmis- sion from 9XL prising one of the three portions of the “Gold Medal Station”, WCCO-9XL- 9WI at Anoka, Minnesota. WCCO oper- ates as broadcast station, 9XL purely as a standard frequency station and 9WI as a general amateur station, the three trans- mitters having independent equipment and antennas but a common _ power supply. Through arrangements made by K.V.R. Lansingh of the Official Wave Length Sta- tion Committee of the Experimenters’ Sec- tion, A.R.R.L. 9XL is operated on schedules regularly announced in QST. The work of operating the station is done without charge by Chief Operator Hugh S. McCartney and his operating staff. S TATION 9XL is a special station, com- While no guarantee of accuracy is made on a gratis service, it is the aim of the staff to maintain an accuracy of 1/10 of 1%, which is materially better than can be “held” by most wavemeters. The fre- quency values are based on the Standards of the Bureau of Standards and have been OST 25 checked by the Communications Labora- tory of The Massachusetts Institute of Technology, also by Cruft Laboratory at Harvard University. Important Notice—The continuation of this free service from month to month de- pends on the response received. Direct ac- knowledgments to “Experimenters’ Sec- tion, A.R.R.L., 1711 Park Street, Hartford, Conn.”, using ordinary stationary or else the special blanks supplied by the Experi- menter’s Section, on request. A goodly number of these blanks has been gathered and as the number grows we will gradually gain a unique and accurate record of trans- mission phenomena possible with no other station. Details on 9XL may be found on page 8 of the June issue. 9XL now uses a small percentage of tone modulation to make the signal distinctive. SCHEDULES MEGACYCLES per (Figures are frequencies in sec.; approx. wavelengths in parentheses.) Sunday Afternoon Friday Evening Schedules Schedules Central Standard Time Central Standard Time Time Schedule Schedule Time Schedule (PM) A B (PM) Cc fora f 2 fo oh. 8:30 3.50 (85.7) 6.50 (46.1) 3:00 10.0 (30.0) 8:42 3.60 (83.3) 6.75 (44.4) 3:12 12.0 (25.0) 8:54 3.75 (80.0) 7.00 (42.8) 3:24 14.0 (21.4) 9:06 3.90 (76.9) 7.25 (41.3) 3:36 14.5 (20.7) 9:18 4.00 (75.0) 7.50 (40.0) 3:48 15.0 (20.0) 9:30 5.70 (52.6) 7.75 (38.7) 4:00 15.5 (19.3) 9:42 6.50 (46.1) 8.00 (37.5) 4:12 16.0 (18.7) 9:54 7.00 (42.8) 8.25 (36.3) 4:24 18.0 (16.7) 10:06 7.50 (40.0) 8.50 (35.3) 4:36 20.0 (15.0) 10:18 8.00 (37.5) 8.75 (34.3) 10:30 8.50 (35.3) 9.00 (33.3) — January 6 \ s Cc 20 B February ; \ 5 ( 17 B DIVISION OF TIME + minuies- QST QST QST nu 9XL. 3 minutes—-5 sec. dashes broken by station call letter every half minute minute announcement of frequency in megacy per second (8.75 megacycles per s« is sent as “S r 75 MC." minute—announcement of frequency in meyvacyck cycles per second Special Notice—If you use the transmissions send Exp rimenters’ Section A.R.R.L., Hart- | note to ford, Conn R.S. K me Strays $s The relay contest is coming. You haven't forgotten the dates—Feb. 6 to 19 inclusive have you? Better mark them on your calendar pad. If you live in the U. S. or Canada, get your entry in while there is op- portunity. It will be too late to enter after Feb. 1.

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nent surrounding the deci- International Radio Confer- ng amateur wavelengths, it sight of a less spectacular mportant victory that the attained in another direc- . court decision in the Dis- Kentucky, where Judge A. M. recently handed down an inicipal ordinances designed ilate amateur radio trans- are unlawful and uncon- annot be enforced. nd the decision is a long now that it can be told. a year ago various towns he country began to pass seeking to restrict and tion of amateur and broad- s within the city limits. The \.R diately recognized this as a amateur operation and had s of the dire consequence ’ all the cities and towns U.S. got the same idea. deliberation at its last R.R.L. Board of Directors best way to combat the tion was to select some xious ordinance and en- court decision against it, uld thereafter be used as couraging similar moves her cities. Director Segal, attorney in private life, League counsel, and we around for a_ suitable on. de ided to open the battle gon, which city had some passed an ordinance that kinds of interference, includ- Director Segal went to Port- brief and take the neces- ecure an injunction in the work he was assisted by our Division director, Mr. K. W. vere ready to file the case however, the city authori- f the suit, became panicky pple-cart by calling a special town council and revising so that it wouldn’t apply to OST JANUARY, 1928 Municipal Ordinances on Radio Transmission Unlawful! By A. L. Budlong* It was a big moral victory, but it meant that we didn’t have our court decision, and several months’ work was lost. About this time, however, another ordinance had turned up which had all the earmarks of being just what we wanted. The town of Wilmore, Kentucky, had passed a measure which required the licensing of amateur stations, a $100-yearly license fee, and various other provisions designed to limit and control amateur operation. Fortunately there was an amateur station in that town, also, so again Mr. Segal went to work to prepare a case. To make a long story extremely short he was successful this time, and after several months work our Counsel-Director emerged with a clean-cut court opinion against such _ regulatory measures, and, shortly after, an injunction preventing the town from enforcing the ordinance. The court decision is so im- portant that we print it in full: “This suit is before me on defendant’s motion to dismiss the bill for want of equity and that it does not state facts sufficient to entitle plaintiff to the relief which he seeks. “The plaintiff is an amateur radio operator. He lives in and operates an ama- teur radio station located in the City of Wilmore, a municipality of this State located in this District. This he has done since October, 1924. He has a license to do so from the United States. It was granted October 19, 1925, for two years by the Sec- retary of Commerce, under the Act of August 13, 1912, and was extended March 15, 1927, by the Federal Radio Commission, appointed under the Act of February 23, 1927, by General Order No. 1 until further orders therefrom. The designation of his station is 9ALM. “On October 1, 1926, the defendant by its Board of Council passed an ordinance re- quiring all persons, firms and corporations to pay a license tax therefor and providing a penalty for failure to do so. The tax provided is not on the property of the radio operator, but on the business of radio broad- casting. Radio communications are all in- terstate. This is so though they may be intended only for intrastate transmission. And interstate transmission of such com- munications may be seriously affected by communications intended only for intrastate transmission. Such communications admit of and require a uniform system of regula- tion and control throughout the United (Continued on Paae 70) 4 fh on eee oe

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nt id 1e n JANUARY, 1928 OST 27 The Grinding of Quartz Plates By E. G. Watts, Jr.* HE HIGH cost of finished quartz os- cillator plates has prevented many amateurs from enjoying the unique advantages of crystal control. Since a large part of the value of a finished plate is presented by manual labor in grinding, it is not likely that existing prices can be lowered. However, the amateur, as he is ac- customed to do in other things, can perform the labor himself. I have found no particu- lar difficulty in grinding to a finish the blanks which are obtainable from optical houses, with no more equipment than a micrometer, some plate glass, and grinding material. The blanks are usually about one inch square, and somewhat over one milli- meter thick, and are cut at a predetermined angle from the natural crystal. Experience has led me to believe that the quality of a plate as an oscillator is in in- verse relation to the amount of variation in the thickness. Most plates refuse to oscil- late without added feedback if this varia- tion is more than one-half percent of the thickness. Another important factor is the condition of the edges. Unless carefully rounded and free from nicks oscillatio.. will be weak. It is not uncommon to find that finishing the edges means the difference be- tween strong free oscillation, and oscillation which added feedback is necessary to sustain. Keeping in mind these requisites for a finished plate, let us see what pit-falls beset us in obtaining them. The plates are cut from the natural crystal at a definite angle to the electric axes. This process has been described in QST for Nov., 1925 and Sept., 1926. In removing any amount of quartz from a plate, one can readily see that this angle could easily be altered enough to upset things. As shown in Fig. 1, the X and Y axis are only thirty degrees apart. To make matters more precarious, plates are often cut at an angle between these axis to reduce the temperature coefficient. The re- sult is that an alteration of only a few degrees is sufficient to shift the plate’s fre- quency-thickness ratio from the 104-meter per millimeter ratio of the X axis to the 117 ratio of the Y axis. This change can occur at a critical time in the grinding process, and result in a ruined plate. Restoring the former relation is of course a very un- certain process. If the plate were to shift from the higher ratio to the lower it could neatly jump the band into which it was to be ground. To avoid this possibility it is obviously necessary to preserve the original angle of #4FM, 1024 S.W. 9th St.. Miami, Florida. cut. One side of the plate is therefore identified and left alone in the grinding process, With the exception of a light grind to make it as plane as possible. There is little evidence that the actual planeness of the faces has much to do with the oscilla- tion properties as long as the faces are parallel. It is well, however, to remove any high spots which might make the grinding difficult on the other side. Beyond this | have not found it necessary to go to any great lengths to obtain plane faces. Having observed this precaution regard- ing the angle there is practically nothing FIG. 1. ILLUSTRATING THE ANGLE OF CUT else which can cause a plate to become a “dud” in the grinding process. It was formerly supposed that a plate might suddenly cease to oscillate for some mys- terious reason, but I have found no grounds for such a belief. The grinding process can be divided into five steps: 1. Taking the light grind on the refer- ence side. 2. Grinding the other side roughly par- allel for a test to determine characteristics so that the finished thickness can be calcu- lated. 3. Rough grinding to nearly the finished thickness. 4. Working the variation down. 5. Finishing (edges etc.). It is necessary to have several pieces of plate glass which may be anything over about six inches square, and 4” thick, for the several steps of grinding, so that a change can be made when the surface he- comes too concave. This has happened when the corners of the quartz insist on going

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OST it is best not to wait ip, especially on the last is very important to be grinding points. to be preferred to other want to trust ordinary is not always uniform, I know nothing about the ality plate glass usually. rface with no resiliency, as Pieces as small as 6” erinding surface, but it margin, so that it is not the abrasive over the edges. rasive are necessary. is not too coarse for stage several thousandths f at a time, and this grade ING USING THE METAL PLATE finishing valves, and will erade “D” might be. I now the approximate grades npound in consistency. epper or finer does for the again, kerosene is used purpose than water, and preferred to emery, as the ten-thousandths is to be preferred, al- lates over 75 meters, as imate closely enough. For however, a ten-thousanths . Starrett’s No. 218 C- is an ideal tool for the faces are smaller than in well to place the microm- of some sort so that both to handle the plate when flat metal plate over the i moistening it JANUARY, 1928 with kerosene so it will stick. This metal plate may be of brass, 4” thick, and about the size of the quartz plate, with a face pre- viously ground flat using the grade “A” compound and kerosene and another piece of glass. Using enough kerosene with the carborundum to allow easy motion, move the plate with a circular motion, describ- ing a circle about two inches in diameter, and gradually working over the whole sur face of the glass. When the plate begins to scrape, use more kerosene. Turn the plate under the fingers periodically so as. to generalize the pressure, using as little as possible. It is practically impossible to determine by any common methods just when the bumps have been worked out, but as this is not of great importance, it can be con- sidered as accomplished after a short period. This completes the first step. Marking the reference side with white paint (do not rely on lead pencil marks as erasing may be disastrous) measure the plate in nine points: four corners, four centers of sides, and center as shown in Fig. 3, marking the thickness; noting the high points, place the quartz on the glass with the fingers properly distributed (without the metal plate this time) for pressure on these high points. Since the plate will be quite thick at this stage, it will oscillate with a relatively large variation (that is comparatively deep hollows and large bumps do not keep it from working). Measuring and grinding periodically, work the variation to a reasonable’ value. Washing with Carbona (or any grease solvent) test the plate for oscillation, calculating from the thickness and wavelength the ratio, and thereby the finished thickness on the de- sired wave. This will complete the second step. Mixing the grade “A” valve grinding com- pound with kerosene until it is quite liquid place it on the glass. It is not necessary to make any changes of glass until the roughing is done. It will not be neccessary to make more than two or three measure- ments during the roughing. 3eing very careful to keep the reference side up, use the metal plate again, and bear with some pressure taking moderate care to equalize the pressure so that it will not be difficult to work out the variation. This will+prob- ably be several thousandths when the plate is within a few meters (by calculation) of the finished wave. Make enough allow- ance so that there will be no doubt about leeway to work the variation in before the finish is reached. The fourth step is the longest and most tedious. Here we discard the metal plate again in favor of fingers and use the fine abrasive. Use just enough kerosene so that p? it 80 ca pl: fo w!} fiv $a) me th: nir det mi poi spe USI it j \ vic be ten pos tho not mie ing only suri may Hill ver} the vari felt as t mar mat

Page 25

ne ze lt b- te of w- ut he yet ite ne JANUARY, 1928 it does not come up over the plate too much, as it is difficult to keep the thickness num- bers easily legible. The old numbers are to be wiped out before each measurement of course, but it is desirable to be able to check how much has come off each time on a certain point. It is best to make measure- ments during this step at an interval of from five minutes at first, down to one or two, when the variation is small, marking the thickness in the usual nine points. A factor related to this stage of the grinding is what may be called “grinding efficiency”, i.e., to be able to make a reduction in the variation without taking off from the lowest point on the plate. It is fairly easy, by care- ful distribution of pressure, to maintain a 100% efficiency. For instance, if one corner of the plate is lower than the rest, and it is desired to “lay off” that corner, it should be found that, while a reduction of several ten-thousandths may have been made elsewhere, the low corner remains the same. By careful application of this principle it is possible to work a variation down within very close allowances. While this treatise will relate to the preparation of plates as low as 40 meters, it is evident that the plates on the order of 80 meters do not require nearly as much care to obtain good oscillation. Thus, with plates designed for 80-meter work, the fourth step can be said to be terminated when the variation has reached a figure near five hundred-thousandths (half a ten-thou- sandth) or even one ten-thousandth as measured by the micrometer, being sure that no high or low spots exist between the nine points of measurement. This can be determined by sliding the plate thru the micrometer across these spots. If an off point is found, it will be necessary to mark it specially and grind it out. The grinding usually proceeds uniformly, however, and it is rare to find an off point. With plates which are to be ground to the vicinity of forty meters, the variation must be worked in as closely as possible. With a ten-thousandths reading micrometer, it is possible to estimate to within five hundred- thousandths. Beyond this point, which is not fine enough for the forty-meter plate, the micrometer ceases to be of use as a measur- ing instrument, and can henceforth be used only to compare different points on the surface of the plate. This is done by what may be called the “slip ard stick” method. Hills and valleys on the faces can be felt very plainly by sliding the plate gently thru the micrometer. It is very likely that variations of less than 25 millionths can be felt in this manner. Differences so small as to not be discernible on the vernier scale markings can be plainly felt. It is a simple matter to mark these spots and grind them OST out. The with rapidity appear also attests their minuteness. which they dis- One must grind very lightly, or a valley may appear where there was a hill. It is also necessary to be extremely careful not to strain the plate during this process, as a piece of quartz .010” or so thick is not very rugged. When the variation has been worked to within the desired value, the fifth and final step is finishing the edges. As stated before, these have a large effect on the oscillation. It has not been determined just what it is that is responsible for this, but nicks which exist on any sharp corner are suspected. Therefore it is desirable to smooth off the 30.9 30.5 30.3 31.0 30.8 30.5 x A x20 31.2 30.6 Raint mark to identi ty reference Side, which must not erase. FIG. 3 ILLUSTRATING METHOD OF MARK- ING THE THICKNESS AT THE NINE POINTS WHICH HAVE BEEN MEASURED WITH THE MICROMETER Specimen markings shown are in the thousandths, and indicate that the plate is high on the lower left hand corner edges so that there will be no nicks. A bevel leaves corners, so a rounded edge is pre- ferred. The corners of the plate should not be rounded too much, however, as it is then difficult to place a round edge on them. Nicks which are visible must of course be ground out, even if a thirty second of an inch must be removed to do it. Grinding off one edge or another does not appear to affect the fre- quency, but has a somewhat haphazard effect on the strength of oscillation. I have not been able to lay down a rule for this effect, and grinding off of one dimension or another may either strengthen or weaken the oscillation. Neither have I been able to find a particular relation between the shape of the plate and the output, although I have seen poor plates which I suspected might be caused by an oblong shape. Rectangular plates are to be preferred to round ones for electrical! as well as mechanical reasons. In selecting a plate which is to be ground to forty meters, it is unwise to use any but those responding to the lowest thickness wavelength relation so that they may be as thick as possible. Plates cut with the thick- ness parallel to the “X” axis show the

Page 26

TEST ber of meters per millimeter. a difference of several thou- finished thickness, and this worth while. With 80-meter is immaterial, as the plates enough in any case. siderably more difficult to plate, I have not No trouble has d with cracking, nor in ob- power for any purpose that te might be used for. In y doubling power and am- necessary high bias battery, difficulty than a “straight er outfit. ty-meter lifficulties. mountings will not be int. A forty-meter plate ry good mounting for best preferable to keep the top ; light as possible, and it of a thin plate, but not so not hold a flat surface. A ‘ will be found convenient. the top plate must exert and will of neces- ry light. A very excellent German silver, or ys of nickel, and are prac- ible. The former is used mn of soda fountains, and ‘tained from this source. tes of any other metal will serviceable. There is it slightly tarnished plates effect on the output. rection, tes is ijunct to the grinding oper- illator. While it may seem ional power oscillator cir- OSCILLATOR CIRCUIT for this, it has certain dis- est work. It is not possible feedback without producing and neither can the feed- be made independent of nge. A circuit which over- ficulties nicely is shown in be recognized as a “modi- r “tuned grid with puate usual blocking condenser crystal. In this circuit, OST JANUARY, 1928 fundamentals can be brought out that will not appear with any other, and without the tube going off into self oscillation. The amount of feedback is smoothly variable by the coupling between L1 and L2. It can be set so that only the principal fundamental of a plate will show up, or so that a collec tion of other fundamentals appear. This circuit also gives a larger percentage of movement of the plate current meter when a fundamental is struck. The movement of the meter is upwards instead of downwards as in the conventional circuits using bias battery on the grid. The response is so large, in fact, that if the meter is of low enough range to give good indication of the weaker fundamentals, the stronger ones will fun it off the scale. Using 45 volts with a 201-A tube a 0-5 miiliampere meter will be found suitable. With the stronger funda- mentals it may be found necessary to re- duce the plate voltage to 22, to keep the current within the range of the meter. The tickler coupling can be loosened to provide the same effect. The range of coupling should be such that it may be reduced to a value equivalent to the amount of feedback which occurs thru the tube capacity in the conventional tuned plate power oscillator. This value may be approximated by observ- ing when oscillation is obtained on the main fundamental only, although others can be picked out with tighter coupling. In order to make the circuit of wide usefulness, con- denser Cl can be made large enough to allow a tuning range from 40 to 150 meters, and further extended by the parallel con- denser C2 when desired. No trouble will be had with critical tuning, no matter how large Cl is made. The condenser C3 is necessary only when there is danger of hav- ing the mounting plates short-circuit the plate supr'y. The choke X can be one such as would be used in a receiver. With this oscillator it will be possible to follow the plate during the grinding process without having to work the variation down a great deal. The circuit is not well adapted to power and transmitting use as it accentu- ates the temperature coefficient of the plate, and the frequency changes also, more readily than do other circuits. I will be pleased to advise anyone who runs into difficulties, if they will write me. THEATRE THALTS 7 HOW SAD AT PARTING time num effie R helo eCXal the | act ; low tive 600 » tive plott some *Br 1 of Au

Page 27

JANUARY, 1928 OST 31 Radio Frequency Chokes for Receivers By Glenn H. Browning* HERE seems to be a great lack of exact data on radio frequency chokes in general and somewhat hazy ideas in the minds of radio engineers in particular as to the method to be used in measuring their efficiency. The writer, in endeavoring to get some exact data on per- formance of a choke for one particular pur- pose, had occasion to talk to a number of well-known engineers and was surprised at the difference of opinion given. Every day, more r.f. chokes are used in various parts of radio circuits so that it is WAVELENGTH FIG. 1. GENERAL NATURE OF THE IMPEDANCE CURVE OF COILS USED AT FREQUENCIES NEAR THE ONE TO WHICH THEY TUNE In practice the curve is found to undergo consider able changes as to shape, steepness of the part A-B and by the appearance of additional humps and hol- lows. These are occasioned by the coil resistance and the manner in which the tuning capacity is placed, that is whether it is lumped in a condenser or dis- tributed along a coil with many turns. The coil-and- condenser, the single-layer coil and the complex coils all show different curves. Which is preferable de- pends on the effect that is wanted—very high im- pedance at one frequency or fairly high impedance over a range timely to analyze their uses and outline number of different methods used to measure efficiency. R.f. chokes may be used either above or elow their natural period.' Suppose, for example, that the distributed capacity tunes the choke to 600 meters. This choke would act as a small condenser at wavelength be- low 600, that is, it would have a capacita- tive reactance, while at wavelengths above 600 it would act as an inductance or a posi- tive reactance. Thus, the reactance curve plotted against wavelength would look something like Fig. 1, the exact shape de- *Browning-Drake Corporation, Cambridge, Mass 1. See the remarks on Fig. 1, of Austin Lidbury on pages 27-31 also note comment Octoher OST Tech. Fd pending upon resistance and the amount of distributed capacity per unit of inductance. Fig. 2 shows a receiving circuit with five radio frequency chokes, four of which are used in different capacities. Radio frequency chokes No. 1 and No. 3 are used for a parallel feed system and are employed to keep radio frequency current out of the “B” supply. Naturally, their impedance to radio frequency current, whose frequencies are within the range to be received by the set, should be as high as possible. Usually these chokes are worked below their natural wave- length. Radio frequency choke No. 2 is used as a positive reactance in the plate circuit of the second radio frequency tube to make the grid oscillatory circuit tune sharply. This coil might or might: not be called a radio frequency choke, but we shall at least consider the definition of that quantity to be sufficiently broad to cover that phase. Radio frequency choke No. 4 simply acts as an impedance grid leak, but should have its natural period with the grid-filament capac- ity of the tube well out of the wavelength range being covered with the receiver. Radio frequency choke No. 5 is designed to choke back radio frequency current so that it will pass through condenser Cg and not enter the audio amplifier. Let us now see how we should go about neasuring each coil for its respective pur- pose. Radio frequency chokes No. 1 and No. 3 should have their impedances as high as possible to currents whose frequencies are in the wavelength band covered by the set. The most convenient way to measure this impedance was found to be the method shown in Fig. 3. A source of E.M.F. whose frequency could be varied was supplied from a five watt oscillator. The voltage across this source was measured by a Rawson thermal voltmeter. The radio frequency choke to be measured and a resistance® of 5,000 ohms were connected as shown. A vacuum tube voltmeter, previously cali- brated, was then connected across the 5.000 ohm non-inductive resistance and the voltae across this resistor noted. Knowing the voltage and the resistance, the current through resistance is easilv calculated. Con- sequently. E and I are known, from which Z (the impedance of the circuit) is deter- 2 Most amateurs know that if there is a nera- tive reactance in the plate of a radio frequency ampli- fier tube, the coil-condenser tuning system will be because no regeneration whatsoever is very broad introduced Author A Tobe Verita resistor was found to be ex- for } r af Author

Page 28

Ost istance of 5,000 ohms in the impedance of the choke was so small that in some be neglected. Of course, if RFC No? ] RFCNoS « No C7 : ¢. Cs if “ ] a — NIN IY VND No 4 +84 +B DIAGRAM OF A used have a smaller im- sistance should be reduced. il slight errors introduced id is not extremely accu- llent for commercial pur- error is made in assuming nee is negligible in com- ' pedance of the choke. This RFC ontest Vac. tube Voltmeter E 2 rHOD OF MEASURING CHOKE IMPEDANCES V is ri Mi a thermo-voltmeter which is co ‘ frequencies. The resistance R is ch t will be small as compared to the imy hoke, thus it becomes fairly cor- ret hat the current thru the choke is EoR mpedance of the choke is Ell or E1R | izht must be given to the avoidance effects from the input system at the 7) small as one pleases by An error is also made in ill the current I passes tance R as some will pass acity of the tube used as a Itmeter. This, however, is he UX-199 tube used has a ent capacity. set of measurements on kes is given in Fig. 4. Choke 148.8 mh. and a eth of 1,397 meters. It was natural period and, conse- \ luetance of BROADCAST RECEIVER TO W VARIOUS POSSIBLE USES OF CHOKES JANUARY, 1928 quently, had a capacicy reactance over the band from 200 to 560 meters. It will be noted from the chart that it was a suitable radio frequency choke to be used for a parallel feed system in a re- ceiver as its impedance was never below 40,000 ohms. Its curve of impedance was regular and, as would be expected, had 3 rising characteristic with 3 wavelength. On the other hand, R2 choke B, whose inductance was 19.4 mh. with a natural period of 3,500 meters, had an im- pedance less than 1,200 ohms and a characteristic which was anything but uniform. It should be noted that in the broadcast band choke A had roughly three times the inductance with a relatively small distributed capacity a combination which would seem to be more desirable. Let us now consider how to choose radio frequency choke No. 2 in Fig. 2. As has been indicated before, this choke is to have a positive reactance so as to make L-C. tune sharply without at any time throwing that circuit into oscillation. By placing a cali- brated variometer in the plate circuit of tube 2, Fig. 2, the amount of positive re- actance necessary to make L-C: oscillate could be easily found. It would probably be about 3,000 ohms at 200 meters. Therefore, the reactance of this choke, minus the re- actance of choke No. 3 (choke No. 3 react- ance would be negative) should never exceed about 2,900 ohms. The necessary measure- ments on radio frequency choke No. 2 con- sist in determining its natural period (this should for a broadcast receiver always be kept below 150 meters) and determining its inductance so as to give the correct react- ance as indicated above. The most convenient way of determining the suitability of radio frequency choke No. 1 is to place it directly across a vacuum tube voltmeter, noting the readings on the meter when different frequencies in the band to be used are induced directly in the choke. Any tendencies toward natura! periods, such as were indicated in choke B, will show up by great variations of the meter as the input E.M.F. frequency is changed slightly. Of course, this choke should have none of these periods for most satisfactory operation. It should also have as high an impedance to radio frequency current as is practicable. This may be determined as previously. Although radio frequency choke No. 5, in Fig. 2, is used in somewhat different canac- ity than any of the others, its prerequisite is large impedance to radio frequency current with no natural period in the range of frequencies to be received when combined in the circuit shown, that is, with R,R- and | Ht Ah tt on 2 ee oo a a. + ho thw a

Page 29

“d e= 1S ye t- ig m 1e 1e 1¢ al 1e ce st ve + be in C- te cy re ed nd eo JANUARY, 1928 C. Natural period could be determined by placing a vacuum tube voltmeter across either R: or Rz and noting the meter’s read- ing as different frequencies are induced directly in the choke. 6 8 er. $33 8 if \ N OHMS > | | | H 8 40000 > 30 000) & B 10000, > oo ————t } 200 250 300 350 400 450 500 550. 600 WAVELENGTH IN METERS FIG. 4. CURVES ON SOME RECEIVING CHOKE COILS Curve A is for a coil with an inductance of 149 millihenrys and a natural wavelength of 139.7 me- ters, Curve B is for a coil with an inductance of 49.4 millihenrys and a natural wavelength of 3500 meters Note that coil A has a lower distributed capacity and a higher inductance, also that it is being operated within reasonable distance of its natural wavelength. The writer has endeavored to give a short analysis of the radio frequency choke prob- lem and he sincerely hopes that these notes may be beneficial to those using chokes in various circuits. New Station Licenses new amateur regulations by the Federal Radio Commission, and a new station license which was gradually to supplant the existing Department of Commerce licenses. Supplies of the new license form have now been sent to the Supervisors of Radio, with instructions to recall existing amateur sta- tion licenses and replace them with the new F.R.C. form. The Radio Act of 1927 re- quires that all persons requesting a station license first make formal application there- fore, and so the Supervisors, as rapidly as they can get around to it, are sending out notices accompanied by a blank application form, which is to be executed and returned with the old license, whereupon the new one will issue. Holders of temporary station licenses issued since March last have al- ready filled out the required application form, and therefore no new application will be required of them; they will receive a regular license automatically, based upon the original application. With 17,000 amateur stations to care for, this is a large order for the Supervisors, and it will be some months before the job is com- pleted. The work has already started in some districts, however. We mentioned last month that we were [* last QST we announced the issuance of OST in general quite pleased with the new “blanket” form of station license provided for us. Current instructions to Super- visors state that inasmuch as all amateur stations, under the law, must be operated in accordance with the provisions of the Radio Act of 1927, the Supervisors need not concern themselves with the details of the station for which a license is requested, and applicants for amateur station licenses need not be required to submit diagrams of their transmitters or to indicate the type of plate supply used, etc. This is a nart of the new plan that an amateur station should be permitted to do anything legal which doesn’t interfere with other services, but that quiet hours are going to be imposed upon it if it does interfere, regardless of apparatus used. It is to be emphasized that the new ama- teur regulations and the new amateur sta- tion licenses have no connection whatever with the new provisions of the International Radiotelegraph Conference. The latter do not necessarily go into effect until 1929 (altho they may before). The new licenses are based upon existing regulations of the F.R.C. and relate to the operating privileges which, with but minor variations, have been in force for the past four years. New instructions governing the issuance of portable amateur station licenses have also been issued. Portable stations in gen- eral are divisible into two classes. The usual roaming station for which a portable license is generally sought will carry the usual station license, with the usual ama- teur call, but the license will indicate that the station is portable and bear the restric- tion “Valid only for operation in the ———— Radio District”. Portable stations desiring to leave the district will be permitted to do so only for definite trips, for the duration of which they will be given a term license carrying a special call which consists of the district numeral followed by the letters ZZA, ZZB, ete. Supervisors of the districts in which the station will be operated are to be notified of the facts by the issuing Super- visor, and at the conclusion of the trip the license will be cancelled and the call re- stored for reissuance. The ZZA-ZZB calls will be issued only to portables which con- template definite excursions beyond the border of their home district. —K. B. W. GEE WHIZ we LOST f\ = ee

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END OST JANUARY, 1928 A Portable Power Supply By Rudolph Sturm* quite a bit of experimenting s of portable and emergen- ters and have never been sat- the methods so far used to voltage plate supply. rk coils with the ordinary a interruption (vibrator) chanical interruption using by a small 6-volt motor 1A. The efficiency of an | is low and the maximum about 10 watts at which motor driving the chopper and the input to the coil ver all efficiency is 26 per antage with this system is ne transmitter tube it util- half cycle. The voltage of es so high that it is almost down the tube somewhere. uld be overcome by using a 1 THE COMMUTATOR OR MOTOR- VEN REVERSING SWITCH il with fewer secondary necting enough capacity it of the coil, in which case ltage will be reduced, and tput too. ethod that seemed promising transformer instead of the taining mechanical interruption voltage. This proved dis- perfectly good transformer as broke down. After building for the purpose it was found teristic was the same as the Minnehaha, St. Paul, Minn spark coil but the output was quite a bit higher as was also the efficiency. It was plain that one could not easily handle much power in this manner, therefore it was de- Chopoer Connected Chopper Whee! o Transformer P2rd muhation / Pr ‘ _ msformer \) + =o Current Break —aZ a (—_______j}4}, — jou Trans Pr, FIG. 1 COMPARISON OF INTERRUPTOR AND REVERSER OR COMMUTATOR The interruptor or chopper can be operated with some satisfaction if a spark coil is used but even then the output will be low and there will be a tendency toward sparking at the chopper. The output of the commutator and transformer will be higher, there will be less trouble with sparking and if a center- tapned secondary is used two tubes may be operated back to back. cided to rebuild the chopper into a motor driven switch that will reverse the current therefore make an alternating current out of the d.c. input which will have the same voltage characteristic on both halves of the cycle. The 6 volts of storage battery supply are changed to something less than 6 volts a.c. and then stepped up as high as wanted by the aid of a transformer.’ The output is limited only by the capacity of the bat- tery if the unit is properly built. My converter puts 100 watts on the plates of two UX-210 tubes and also supplied 7.5 volts to the filaments. (See Fig. 3) With a 12-volt battery as the source of supply 250 watts were fed to three UX-210 tubes in parallel besides the filament power of 7.5 volts and 3% amperes. The a.c. voltage can of course be stepped up or down as desired by 1. The voltage at the output brushes is somewhat uncertain and should be measured with a good a.c. voltmeter, which will give a nearly correct reading The uncertainty as to IR drop and wave form makes calculations worthless. The ordinary 0-15 a.c. filament voltmeter is not of much value at voltage below 7.—Tech. Ed Fi¢ ing mu mo for she que tor con P R.P con: arre seg E

Page 31

Tr it ie le ly ts vd

JANUARY, 1928 arranging proper windings and taps on the transformer. As to the construction of the converter I believe the photos are clear enough to show how the parts are arranged. The i-section commutator shown in the draw-

Brushes on only facing Sudeé are Shown

MOMS LOM a/e Y of Segments % i A ond Brush holders, ry

as +4 Ow os 4S, ‘" 8 > A . \ » ‘ As @ ? SA XO Y XQ “ 4 ww HY | | ns.

Siping ond ry Trp) Brush Holder Construction po$-----F\ \_ dk Jo grass Sate Some 2 | | ~ . Brush | . Fiber Spring || q ] 6 —

CONSTRUCTIONAL DETAILS OF THE COMMUTATING ARRANGEMENT FIG. 2 ing of Fig. 1B is really a 20-segment com- mutator taken from a discarded 110-volt motor. Five segments are tied together to form one. They are interconnected as shown in the diagram. The output fre- quency depends upon the speed of the mo tor and the number of sections in the commutator. The formula for this is P R.P.M. Fr - where F = frequency, 120 P number of commutator segments, R.P.M. revolutions per minute and 120 is a constant. The commutator brushes will have to be arranged as many degrees apart as any two segments of opposite polarity. Example: j-segment commutator 90° 6-segment commutator 60° OST

1 7 ~ - _ 8-segment commutator 45° or 105 10-segment commutator 36°-108°-180 etc. The motor driving the commutator and slip rings should be shunt wound, mine be- ing a 110-volt motor that I rewound for 6 volts. As to the dimensions of my converter; the motor is 342” in diameter and 3%” long, the commutator 1%” in diameter and 4” wide, the slip rings %” in diameter and 3%” wide. The commutator brushes are 4” » 5g”, the slip ring bruhes 4” square the base 7” x 3%”, the height is 5” and the weight 4% lbs. The advantages as compared to a motor- generator are that the cost is low, the de- vice weighs much less and is more com- pact, also it is very rugged, not being in- jured by getting damp or even wet. The transformer can be put in a water-proof case. Since the transformer can be changed at will the whole rig is very flexible as re- gards output voltage. Summing up the whole thing I think it is the “berries” for a portable or emergency transmitter when a.c. mains are not available as the whole transmitter can be supplied by the battery that “Henry” puts in the “baby Lincoln.” The circuit of the transformer primary winding is never broken, therefore no un- safe potential is developed in the secondary winding. The duration of the apparent short circuit is very small; practically no sparking will be evident. If more than 12 volts d.c. are used it may be a good idea to insert a small choke consisting of few turns of heavy wire on a core choke in the bat- tery leads as shown in Fig. 1B in dotted lines. As to procuring the various parts, an old commutator can be had for the asking et almost any electric repair shop. The only requisite is that it must have an even num- ber of bars so as to divide up into an even

Aatler, YY - Se wn 4 See x oo ) Mot — ~~ > = © be — = bef be § e . =_— a FIG. 3 DIAGRAM SHOWING CONNECTIONS TO A TRANSFORMER SUPPLYING BOTH PLATES AND FILAMENT CURRENT TO A TRANSMITTER OR A RECEIVER This permits the use of filaments which will not operate directly on the battery. number of sections. As an illustration let us say we got a 32 segment commutator from a G. E. 4 h.p. d.c. motor and wanted to make a 4 section commutator out of it. We would divide 32 (number of segments) by 4 (number of sections we want) which would give us 8 bars per section that must

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36 OST shown in the drawing only ne on the risers—the com- d of the front as shown. M { of % h.p. have a %-inch t the commutator it is 9/16 %. To get the shaft out tor that has been sawed ie armature the commutator to around 200° F., and then * the shaft pounded through; +} with a light hammer, not a g¢ sharply. ngs are turned out of brass have an inside diameter the the commutator (nine- inch) so that a fibre rod (not driven) through the ent. A hole is then drilled fit tightly on to the motor } eve that those who have no lat well by having the com- » rings fitted on the fibre the motor shaft bored or or repair shop or machine le part ought to run true oY a lders for the slip rings may 16 3/32” copper sheet. 6 or 3/52 — ror w OI THE COMMUTATOR DEVICE ‘ e motor is the commutator into which the rrent is fed as shown in Fig. 1B. The inte tions between the commutator bars can he thi view or the end view. At the end of r shaft are the two slip rings from which the tine current is drawn and fed to the tra T ble at any copper and brass nd is easily bent into the the drawing. The brush of a clock spring bent into wn in the drawing. This heating the end of the d red and then bending it with the aid of a pair of pring is then hardened again and plunging into must be taken to redness ular care uniformly and hot enough ng it. JANUARY, 1928 The commutator brush holder can be made more simply than mine by using sheet cop- per. The spring tension against the brush- es can well be made as shown since the con- struction is simple. The brush holder open- ing should not be quite as broad as the commutator and I believe not more than 4” wide. The brush material and pig tails can be bought at a motor repair shop. It is cheaper to buy enough material for all the brushes and cut it up with a hack saw rather than to buy small brushes of the exact size wanted. The brushes are drilled and tapped for the 6-32 screw ends of the pig tails and these are screwed in tightly. If another type of pig tail is used it is easy to contrive a way of fastening, re- membering that it is important to secure good electrical connections since this is a low voltage outfit and therefore all resist- ances must be kept down. For the same reason when buying the brushes try to secure the special low resistance graphite. If you cannot get that you can buy Ford generator brushes which will have to be sawed and sand-papered to size. Because of the low voltage it is also advisable to wind the transformer primary with No. 10 wire or larger. A transform er whose core has a cross section of one square inch will require about 7 turns if the commutator is operating at 200 cycles. Knowing what secondary voltage is want- ed one can figure the secondary turns by direct ratio. An interesting test of the smoothness of the output was accidentally made one evening when the power supply went off so that our broadcast receiver could not work. I connected the 110-volt convertor output to the B eliminator and we listened to the end of the program. Horace A. Beale, Jr. With the passing of Horace A. Beale, Jr., the League has lost a staunch friend and supporter. Mr. Beale, who was a director of the League for over two years, was the owner of stations 3ZO, 30I and 8XW located at Parkesburg, Penna. 3ZO was probably the largest and best equipped station that amateur radio has ever known. As the result of a long illness, Mr. Beale became inactive in amateur matters and died on September 6, 1927, leaving many friends among the amateur fraternity. Va of ore ing Lo FIG the a ni wor: this 1B, nois proce by 1 2w this geste are peciz form tube W) broac count even baug perfe plifie: most

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ww JANUARY, 1928 OST 37 The Helpful Audio Filter the that HEN one has reviewed all different opinions it seems there is no audio system that will suit everyone nor even an audio system that will suit the same _ person under all weather conditions and for all | Yyy . A Y X BR VWOISE REGION Bids ahd ¥ Md a r?) oo 1000 10,000 crcliés FIGURE B. PURELY IMAGINARY AUDIO CURVES TO SHOW HOW A FILTER MAY SOMETIMES IMPROVE RECEPTION In the case instance an audio system hav- Figure 1A, so as ody” varieties of signals or music. of telegraphic signals one may for ordinarily wish to use ing a curve like that of to gain the full benefit of the “1! which ApS T° ¢ ()3ii : “Hi 30) og Sié _— =| = « = = C Se +B THE AUDIO REJECTOR SYSTEM DE- SCRIBED BY MR. HATRY FIGURE 2. the lower tones lend to the signal, but on a night when interference is bad and static worse it may be a great relief to whittle this curve down to something like Figure most of the horrible + 1p . P 1B, SO as LO lose noises, even if the signal suffers in the process. This particular job can be done hy the simple rejector system of Figure 2 which has been repeatedly described in this magazine by Mr. Hatry. As sug- gested in the label of Figure 2 such filters are largely a matter of cut and try, es- pecially as the inductances of the trans- formers depend on the tubes and the tube voltages. When it comes to the reception of a broader band of frequencies such as en- countered in radio telephony the filter is even more useful, of this Frederick Dellen- says in a letter, “This is a standard way of correcting am- and loud speaker behavior. It is al- axiomatic that volume and quality baugh, Jr., perfectly plifier most are mutually exclusive and a sacrifice must be made in one to improve the other. Therefore filter systems for correcting de- fects appear to be reasonable since if the same correction were to be made in the transformer or loud speaker it would usually mean lower amplification per stage $a ee7¥——> [8 Out Wooden Choke Coil farm - B FIGURE 3. THE CIRCUIT AND WINDING FORM OF THE COLONIAL “TONE PERFECTOR” The switch D is opened when speech be received. only is to or greater damping and the loss of loudness is gg the same.’ Mr. Jack W ard of 6KC has furnished the details of one simple filter which are given in Figure 38. This device is of the low pass variety and is devised to correct am- plifier systems having a bad bump in the vicinity of 3500 or 4000 cycles which (though it ordinarily helps out most loud speakers) is bad when one is working with r _ | | THE COLONIAL FILTER WHOSE CONSTANTS ARE GIVEN IN FIGURE 3 a good head set or a good loud speaker, especially if there is a noisy background since the noises are usually on the higher frequencies. It will be seen in the photo- graph of this particular filter and in the diagram of Figure 3A that a switch is provided to be opened when speech only is

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OST The effect of this is to er pitches off still further. D 1ugh suggests a modification ‘Ts YIMA a —+- — of ef FIGt \N ADJUSTABLE LOUD SPEAKER UGGESTED BY DELLENBAUGH ystem which is shown in figure differs slightly in d in having two additions allow the higher fre- to some extent, the prin- he system then being to cut ies around 2000 or 3000 all, and to reduce those 5 ‘a a ' Z i 4 Ob std ew"? => if rz ‘I — FIG AN ADJUSTABLE BAND PASS FILTER es somewhat. The amount vhat” repends mainly upon C,. The other addition is the vhich should have a range 50,000 ohms and controls the the system as a whole. This of the switch D in Figure enbaugh also suggests the Figure 5 which is a band ter stopping everything be- 5500 cycles. Since one does have complete elimination but pression the controlling re- provided as before. Such a haracteristics the reverse of ud speakers ordinarily used therefore be used to correct problem is simply to cut gh end of the curve one can the job with as simple a con- wn in Figure 6A which is in article by H. J. Barton Cy} ] fenr Wire less. The part of JANUARY, 1928 the system to the left of the dotted line will be recognized as being the usual thing in loud speaker filters designed to keep the current of the power tube out of the speaker. The group of condensers and the flexible leads are provided to give an ad- justable cut-off on the high frequency end. This part of the device can also be built with a fan switch or with a comparatively large condenser in series with a resistance as shown in Figure 6B. These variable filters have the advantage over ordinary — a x" —— — — ra “Se ‘ae ‘ae ‘oe ‘ek a a oe = taf , a Sy) 4 , _— so ls. nll $$ —_» , ’ A — —$___——_» FIGURE 6. ADJUSTABLE FILTERS WHICH ALSO KEEP THE PLATE CURRENT FROM THE LOUD SPEAKER fixed ones that it is easier to secure some sort of an agreement of the set with any loud speaker it may happen to be called upon to work with. —R. S. K. Southeastern Division---Florida Convention january 13th - 14th, Hotel Alcazar, Miami, Florida. circles on your calendar. The Miami Amateur Radio Club is sponsoring the convention and is planning a wonderful program. Don Mix is expected to be the guest of honor. Director Dobbs has promised to be with us and Headquarters will send Treas- urer Hebert to represent it. All members of the Southeastern Divi- sion are cordially invited to attend—and hams from other parts of the country spending the winter in Florida. Write E. G. Watts, Jr., Secretary, 1024 S. W. 9th St., Miami, Fla., and tell him you will be there. | OOK at the above dates and put red al CO 26 ne O’V te] flo Wea fo. Da ter tri ma fro ap} in abe Dis the

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ly ad ni, ed mi the ful of be AS- vi- ind try ~ St., JANUARY, 1928 OST nu3CAB HE ether stresser known as radio sta. tion 3CAB is located at 38°-56’-13” North and 77°-2’-2” West, a point known to the Post Office Department as 1311 Spring Road, N. W., Washington, D. C. The call 3CAB comprizing the initials of the owner and operator, C. A. Briggs, was secured by the virtue of self-restraint. He put in his appli- Finally, in the summer of 1926 the accumulation of equipment in preparation caused an attempt to be made to extend the range of the perimenting was continuous. station. Results followed at once. It seemed that everyone reported the signals from a five watter. Improvements have continued and the present transmitter con- sists of a 203-A in a Hartley circuit. The _ inductance cation for this call before it was issued and then waited patiently until its turn arrived. The station was first put on the air in the spring of 1922. With the aid of a spark coil and a borrowed VT, signals were put out and reported by local stations A VIEW OF as QSA. The ex- The short-wave equipment pression had not come in- lamp stand. to use. The first circuit used was the well named “sure-fire” arrangement. Frequently, the result of tightly coupled grid and plate coils, such a transmitter showed a versatility not suggested by the amount of wire in sight. Care had to be taken or else in addition to transmitting on two hundred meters, signals would be dispatched on 360 meters or there- abouts. After two years the station was moved about half a mile to its present site. NAA could still be tuned in and heard plainly on 2650 meters. This was marveled at as the new site was surrounded by three systems of tin roofs bounding an enclosure laced over with a wonderful screening system of telephone wires. Viewed from the upper floor they seemed close enough together to walk on, and helped to explain the reason for the dividends of the Telephone Com- pany during the last few years. The an- tenna hugged closely one corner of the triangle and extended upward into the metal maze, Due to the inferiority complex arising from the surroundings aggravated by the appearance of BCL antennas _ nobler in equipment and competency for space above the housetops, the boundaries of the District of Columbia for a long time marked the active range of the station. However, ex- THE STATION she “ is on the table to the left and Changing “PR” The cardboard pockets one band to the F holding the blank messages are at the left, attached to the other. The key the other table holds the broadcast set. consists of eleven turns of %4-inch copper tubing. The tuning con- denser is placed across the whole coil and_ trans- mission may be had in either the forty-or eighty- meter band by ad- justing this con- denser. It is not necessary to shift the clips on the inductance when from is located in the primary of the plate transformer. The filament of the tube is supplied from a separate trans- former. As may be seen in the view of the sta- tion, the transmitter is mounted at the left end of the table on an extension to the table top. The pole transformer giving 1100 volts and the chemical rectifier may be seen underneath the same table. Direct- ly below the table extension holding the tube are mounted the filament trans- former, plate milliammeter, plate choke, grid leak and grid choke. This last choke is necessary because the leak goes from the grid to the filament center tap and is therefore in shunt to part of the helix. Two keys are provided at the right of the table. These are covered by a small ele- vated shelf protecting the keys from acci- dental closing and affording a place for messages disposed of. One key is a side contact key for regular use and the other is a straight key for visitors. The Zeppelin type of voltage-feed Hertz antenna is used. The amount of space for erection being small, its dimensions are scant and it is necessary to use 16 turns of %-inch copper tubing in the feed circuit. The condenser is used in a series connection for operation in the 40-meter band and in

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inductance for the 80- and e oscillator from the antenna steady note on a wind-driven the signals could not be read ng was used. Although this RNER OF THE set-up shown is for the calibration Measurements of resistance, capacity, tage and current have been made in th various undertakings. The table erves for a radio clinic and has been table for removing appendices of sets The loud speaker mounted up in rnishes entertainment when that is LABORATORY wi vely tight coupling between results are excellent. may be seen in the center table. A close-up is also ounted or. three legs which ible increase in the effective ircuit is of the familiar pe empleying one variable tuning and one for the con- Instead of employing - changing the range of the | condenser is used and when the tuning condenser, it shifts the fi rty- to the eighty- Clips are provided for this may be connected in the short order. Although the ta “thing of beauty”, it works ich, after all, is what a re- lo. It has a characteristic of rs built at this station during vears, the detector tube is de-down. This enables the le leads to be obtained in this i é ( ition. ectifier bears somewhat the the station as a flea to a ves a great deal of attention! with 500 volts on the plate le team product was used on rehabilitation of aluminum a mussy process. Then the reased to 750, the jars to 30; itions used. These did fair- idence for any conclusion could some solut Ions turned brown, OST JANUARY, 1928 some black, some stayed clear, and some ot each color worked and some of each shack did not. The voltage was then increased to 1100, the jars were decreased to 20, and in defer- ence to the much advertised desirability of thrift, a new batch of solution, couragy ously diluted, was used. Forthwith things began to happen. Afte) sending “cq” the dial seemed full of re- sponses, a “grand and glorious feeling”. The innocent and quiet coils belied their looks and nipped brutally the skin of in cautious fingers. This caused a revision i several ideas that the lesson was learned that the frequency of high frequency burns should be low. On the table to the left of the one holding the transmitter is a broadcast receiver and when it is tuned to a local station, and the plate voltage of the transmitter is kept down to 550 volts, the transmitter does not affect the BCL set aitho both are using the same antenna. The BCL set is con- nected to the antenna thru the capacity ot the change-over switch. Key clicks may be heard but these come entirely from the primary a.c. supply and are not affected whether the transmitting tube is in its socket or not. The BCL set is the loud- speaker shown above, and also to others up- stairs and in the basement. The turned on or off by pushbuttons located at convenient points throughout the house. Flash light bulbs are placed in series with the tubes, each serving the quadruple pur- connected to set 1s roo"; + » = ~oiatcte to” See vw - EP aa? a ~ ——\ SP o THIS WORK TABLE SHOWS A NEATNESS THAI MIGHT WELL BE COPIED BY MANY Everything is within sight and reach which should he of a considerable help in getting work done. The “roving” lamp may he seen in the upper right hand corner. pose of a rheostat, a light for a dial, a pr tection fuse for the tube filament and an indicator of trouble frem poor and noisy contacts which might otherwise be errone- ously recognized as static. The filament current is 0.20 instead of 0.25 amperes and the strength of signals does not seem to be materially reduced. The tubes seem to last indefinitely and the last one purchased cost ' Ji $3. pas vid tal — Te ope chs ing a act tnt ari any ho to alo of an; all fro sib al wh rel wil bre me nes eve At lef the tac PVE ad on thi m hee

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928 lac 100, ig” heir that irs ing the ted | Ket ud- up- uld rhe 1928 JANUARY, $3.50. This gives an idea of how far in the past they were bought. A “B” battery charging system is pro- vided for the Edison Battery below the table. Plug connections for operating the “A” battery charger in the basement below sre also at hand. One plug is used for operating the transmitter and all the charger and auxiliary devices such as solder- ing irons, etc. But one thing can be done at a time with the result that there are no accidents from crossing circuits. The work shop of the station has several interesting features. By means of a simple arrangement, the light may be shifted to any position in a large area. The light is hooked over a wooden "pole running from left to right and may be moved to any position along it. Eyelets are screwed into the ends of the pole and two wires which run at right angles to the wail, pass through the eyelets allowing the pole to be moved either away from or towards the wall. It is also pos- sible to remove the light from the pole i a few seconds so that it may be used else- where. A pilot reminds the with the iron connected. brackets are provided for ment and for drills. The arrangement of the sult of evolution, those being most fre quently used at any position along the vench are placed nearest that point. Supplies of nuts and a quantity of parts are kept in glass jars. Just a small portion of these are shown in the photo- graph, the majority being on shelves not in the picture It is probable that handled more messages than any other due to special circumstarces. light for the soldering iron plug worker not to leave the shop Swinging service soldering equip- tools is the re- screws, this station has without schedules station. This is Since the first amateur if September, 1926, over a thousand mes- sages have been handled, a negligible por- tion being the result of schedules. A con- siderable portion of the traffic has related o government Organization has done what otherwise re- quires schedules. The owner is in one of the government departments. He has busi- ness dealings and friends in practically every one of the er cities in the country. Attached to the lamp stand at the operator’ left is a series of cardboard pockets. *e these, addressed message blanks are placed according to localities. When good con- tact is made with a station, and there is any event of incident or business that can be advantageously handled by radio, it is placed on the partially filled blank and sent. In this way the other operator is given a live which he can deliver. times the other operator has to phone the message and get a + business. lare message Innumerable heen able OST 41 reply at once. In this way a series of mes- sages of special interest and potency are exchanged. However, in addition to this traffic a large amount of other messages has been handled. A perusal of them is engrossing. Births and deaths are announced. A young- ster in a distant city sends a message from his own station to his uncle. The uncle is profoundly moved, and in acknowledging it THE THREE-LEGGED RECEIVER The plug-in fixed condenser may be seen just above the tuning condenser. The two-pronged plug is used to connect the set to the “A” battery circuit. tates that it was some time after he was born that the pony express started across the plains, and now, boys flash news about the country in an instant. Many rubber-stamp messages are in the lot but they are often of importance. When they are from or to a person for the first time they should be given great weight. Most people, when they receive a radio mes- sage by phone are somewhat stunned, and their reply is generally rubber stamp in type, but the message is really very im- portant under the circumstances. Some people are tremendously interested in re- ceiving or sending a radio message, others are not. The persons may or may not be important, the'r interest is a matter of temperament. WeStrays "$s A copy of the index to volume XI, the 1927 series of QST, was included with all membership copies of the Dec. 1927, issue. Newsstand readers, or members requiring additional copies, can obtain them from QST’s Circulation Dept., 1711 Park St., Hartford, Conn., at 10¢ per copy, stamps acceptable. Don’t forget to send your card to Inter- national Contest Headquarters if you want to enter the Tests. Entries close Feb- ruary 1! No chance for U. S. or Canadian amateurs to win prizes or get the official test messages if they forget to enter before that date.

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OST JANUARY, 1928 Rotten Bunk By The Old Man rner, what’s all this bunk riting to our Senators to the rest of the world out of we amateurs shall have it I copied something out this general effect the other ssible that some of us think ts of the Washington Con- this sort of action? ecause we shall have to on our forty-meter wave these hair-trigger young uateur radio is on the skids. ime to send out for a small A few drops of it the Wouff Hong just before ter into the patient would good. d what they pulled off in irlv closely, and if I remem- were about half a hun- and distinct nations that sat ut the wave-lengths. Also, aright, there were several amateurs that wanted a ectrum. There being only was voted early in the pro- the amateurs could not have more or less misty impres- a very few of the nations te ideas on this subject. sense. fireworks had been set off rton Conference, it turns out R.R.L. and the I.A.R.U. have national recognition for ama- in addition a band between another between 75 another between 41 and 43 around 20 meters, another eters, 10.7 meters, and another ims around 5 meters. eh what? So frightful ked to write to the United to scrap the whole works. young squirts had operated ir, with spark coils and ro- | with 200 meters as the top ild not be writing their used to think we were lucky, work DX. I don’t suppose r heard of Paul Godley and satlantic sigs at Ardrossan, Paul sitting up all night in pouring rain. That was all neters. I don’t suppose they Fred Schnell and Deloy in ing back and forth every on 110 meters? And of all vs we did as we gradually wavelengths, discovered the new things and pointed them out to the Radio Corp. Instead of writing to our Senators, we ought to be inquiring into what kind of osteopathy it was that you and Stewart were using on them down at Washington to get as much as you did. We've got enough frequencies to do everything that anybody can think of. The forty-band may be squeezed some, but it isn’t all gone, and even if it were, there are all the others. The trouble with some of us is that we get the notion that the frequency we hap- pen to be on is the only workable fre- quency in the spectrum. Our eighty-meter band is the best band we have for all the working back and forth inside our own country. It doesn’t skip much, and it works late into the morning and starts early in the afternoon. And the 150-band is just as good as it ever was. What’s the use of writing the Senators about either one of these bands being worn smooth, when they have just as good mile age in them as they ever had? And enough of the twenty-meter band is still there. Nobody has pinched it or put it in hock or fed it hooch. It’s just as good as it ever was. And Final Authority said at the Radio Club the other night that the upper end of the new ten-meter band had indicated positively that it could do things that would make an old timer’s mouth water. His language was considerably more ele- gant than mine and Radical’s, but he had us all haired up just the same. If these nuts who want us to write to our Senators could be sent to Washington and made to go up against those hard-headed boys they call statesmen. it would be the best dose of medicine any of them ever had in all his life. Those folks in Washington have a way of making the proponent of an unreasonable measure look like the worst plugged nickle that ever came out of Chicago. I can imagine a committee of red-headed amateurs appearing before a Senate Committee and asking them to make reservations in the Radio Treaty because the amateur’s forty-meter band had been pinched in a little at the waist, and then having one of those smart fellows from the Radio Supervisor’s office point out that the 150-meter band, the 80-meter band, and the mutilated but still peppy 40-meter band. the 20-meter band, and the 5-meter band were still there—with a new band at 10 meters to boot. The result would be too (Concluded on Now listen: page 44)

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7 1e 0 JANUARY, 1928 OST 43 Matching the Transmission Line to the Antenna By Walter Van B. Roberts* F a transmission line for current feed is connected right into an antenna as in Fig. 1 without any transformer, not only will the range of the station be reduced, but meters placed in the transmission line can no longer be trusted to read the antenna current. Hence both for the sake of in- creased output and convenience it is worth- while to give some attention to the method of connecting the line to the antenna. Suppose the transmission line is made of two round wires of diameter d, with their centers D apart. It is easy to derive from first principles the formula for the charac- teristic impedance of the line—that is, the impedance of an infinite length of the line. The formula is: 2D Characteristic impedance = 276 log . d very approximately. Next suppose the antenna is a plain open oscillator—a straight wire a little less than half a wavelength long—say about 444; of a wavelength long. (See QST p. 16, Oc- tober, 1926). The radiation resistance of such a wire working at its fundamental FIGURE 1. THE TYPE OF ANTENNA UNDER DISCUSSION If used in the simple form shown it is operating with various currents and voltages along the line and the current in the top cannot be foretold with certainty from a meter in the line. is in the neighborhood of 70 ohms, what- ever the wavelength. Hence the total re- sistance of the antenna will be probabiy somewhat less than 100 ohms. Now the problem is to match the trans- mission line whose characteristic resistance we will call R:, to the antenna whose total resistance we will call Rx. The first thought would be to choose D and d in building the line such that the formula given above makes Rr come out about 100 ohms, so as to match Raz. But in order to do this it will be found that the wires would have to Engineer, Radio Corporation of America, 155 Hodge Road, Princeton, New Jersey. be kept too close together to allow main- taining an even spacing. Hence it is bet- ter to build the line with a convenient spac- ing, calculate Ri, and then interpose a step- down transformer between the line and the antenna. A simple and highly efficient transformer (it is not the usual sort of transformer with Ly a ec — 0 Antenna ¢ © | | +i L2 Y FIGURE 2. A TYPE OF SIMPLE NETWORK WHICH MAY BE USED AS A TRANSFORMER TO MATCH THE IMPEDANCE OF THE ANTENNA TO THAT OF THE R.F, TRANSMISSION LINE. The two coils Ll and L2 may conveniently be halves of the same cylindrical winding which has been cut at the center to provide antenna terminals and across the outer ends of which the r. f. line and the condenser Cl is connected. This is the output transformer and goes at the antenna end of the line. primary and secondary windings, but much better for the particular wavelength for which it is designed) is shown in Fig. 2. The transmission line is to be connected to the left hand terminals and the antenna is cut in the middle and connected to the right hand terminals. The capacity of the con- 1 Ri-Ra denser should be — \/ —— farads, 2rfR: Rx where f is measured in cycles per second and R in ohms. The coils are preferably equal, and if coupled at all should preferably be so coupled that if the condenser were short circuited and the inductance between the right hand terminals then measured, the coupling would increase the total induct- ance. This total inductance Ri-R,i / Ra so measured should be \ 2af R.-R, Henrys so that if the two inductances are equal and are not coupled to each other, the inductance of each would be half of the above value. The input end of the line can be coupled’ to the oscillation circuit as shown in Fig. 1. As has been noted repeatedly in QST' it is de- cidedly preferable to couple the line rather than to tap the ccil P. The same statement holds good for single-wire lines Tech. Ed.

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ny convenient size, in series r of proper capacity to tune nee at the frequency used. the complete set-up. Any r or amplifier may be used. il Le is shown split with the the middle for the sake of To the Line L3 C3 L3 WOU] GOVTTTTN) Pp rHE INPUT TRANSFORMER EEDING THE LINE nee of the transmitter oscillator or the amplifier if one is used. The h it operates does not matter. L3 coil split at the center by the ( The coil and condenser must the working wave when the line ansformer L:, L:, C: is all board held up by the antenna. EXAMPLE illustration suppose the be 40 meters then frequen- 0 cycles per sec. The over- tenna will be about 44% 17.6 meters. Let us sup- a single wire of small the total resistance of the about 100 ohms. Suppose mission line is made of ter in diameter, spaced 50 n by formula, 100 g 552 ohms l 100 and R 552 the 552-100 81.7x«10 » (552) 100 L, and L. will have a 100 15x10~° henrys or 552-100 ppose that L, and L of a single straight cyl- hich is cut in the middle to on of the antenna as shown this coil before cutting OST JANUARY, 1928 would have 4.5 microhenrys inductance. (The coil should be firmly mounted before cut- ting so that the halves won’t move.) Coil L; may be of any convenient size, the only requirement being that L, and C, are related by the formula F 2n\ L: C For definiteness, suppose L 10 micro- henries 10° henrys. Then we must have l 7.500.000 2ay\/10°C whence C 144.5 x 10° farads approxi mately, or 44.5 micromicrofarads. After the antenna and transformer and transmission line and coupling device L, C have been constructed according to the fore- going formulae, it should be only necessary to vary the oscillator frequency and coupl- ing to the transmission line to obtain maxi- mum output. If everything is built cor- rectly a meter in any part of the line will Antenna fii L, TONY "TM a \& 4 weengae) P regan | “A | 7 4 | Fi G4 FIGURE 1. THE COMPLETE SYSTEM The output transformer L1, L2, C2 is mounted so as to be supported by the antenna while the input transformer is naturally located in the station. The line may be several hundred feet long without notice- able harm read proportionately with the antenna cur- rent. The actual antenna current will however, be larger than the line current by a constant factor because the step-down transformer increases the current in the /R ratio \ Ry It is particularly pleasing to note that several hundred feet of transmission line may be used without any noticeable loss of antenna current. ———_$ ———— Rotten Bunk (Continued from page 42) painful to dwell upon. ‘Tis better that we draw the veil. Better get out the old Wouff Hong, son, and send down to the store and get a few drops of common sense extract, and pro ceed as per directions

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~~ e JANUARY, 1928 OST 4 ur The Unimportance of Short Leads By L. W. Hatry* HORT-LEADS have their place in set design. However, we often use leads too short for best results, convenience or appearance. The first of these things is italicized because there seems to be a strong belief that leads cannot be too short. In the italicized words we have a par- tial explanation of the fact that often an ex- perimental layout with long leads outper- forms a _ supposedly “decent” duplicate assembly with short ones. (Of course, there are plenty of set-makers who use long leads and fail in both best results and con- venience.) The conditions under which to judge the need for shortness of connections can be settled by answering this question “Can the leads be harmful?”. The answer to the question will be, “Yes,’ when the leads add excessive R, Lor C. We can guess closely at R and the rest, (they are interlocking effects as usual) if we consider the placing of the connections as: (1) Leads within a tuned r.f. circuit; (2) r.f. leads outside a tuned circuit, and (3) other than r.f. wiring. Fig. 1 shows a tuned circuit. The coil and condenser are shown with terminals which we may pretend are attached in the ’ Bcd me FIG.1 ; FIG. 1. TUNED CIRCUIT FOR DISCUSSION Because the coil L and the condenser C are most talked about the builder is inclined to think that the wire between them are to be made as inconsequential as pessible but shortening them too much is quite likely to make trouble instead of curing it. usual way. The coil and condenser are drawn heavily to make sharp the dis- tinction from the leads which are drawn lightly. Within this tuned circuit the cur- rent at resonant frequency oscillates back and forth, suffering no opposition save from the resistance of the circuit. Conse- quently if we have gone to considerable trouble to produce a good coil and con- denser it is important not to harm that achievement by using German silver leads or by addins resistance in some other fashion. We can most effectively add re- sistance to the tuned circuit by placing L so close to C (while trying to get short leads!) that eddy currents are set up in the plates of C, or by getting L too close to *Radio Department, Hartford Times, Hartford, Conn. any other mass of metal. This exact method is used in more than one receiver to prevent oscillation on the lower broadcast wavelengths. The coil L ought to be kept FC _ SCHEMATIC LAYOUT FIG. 2. A TYPICAL LAYOUT THAT DID NOT PROVE GOOD Note that the part of the filament bus marked “Ret.” is in the tuned circuit therefore has an r.f. drop along it. This makes it impossible to have both the filaments and the condenser at ground voltage. Note also the loop made by the circuit. at least 2/3 of its own diameter distant from the large metal areas. The actual resistance of copper leads not smaller in gage than the coil wire is of no importance in the usual hookup. Leads in a tuned circuit can produce several effects by adding capacity and in- ductance. If close together and insulated the leads can add resistance by becoming a poor condenser but uninsulated leads can seldom do worse than add “good” capacity which builds up the circuit minimum. As no length of connection within reason can do worse, why worry? In a multi-stage tuned r.f. job long leads can couple by capacity or inductance but even these things are unlikely to be important compared to coil-to-coil coupling. Not until the _ set has become fully neutralized are these effects the largest ones. In the usual re- generative set, hand-capacity will result from a large field due to long tuned-circuit leads, which may seem short. In Fig. 2 the heavily drawn leads seemed short but they produced a single large turn that had a large field and with which the hand in- terfered although the variable condenser itself was grounded properly as touching the finger on the shaft proved. Not evena metal dial will always cure a case like 2.

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16 OST [ leads in this set directly from the the condenser, behind the con- aced the leads close to each their area of operation. 7 L | LAYOUT FIG E CIRCUIT REVISED TO CURE THE ULTY MENTIONED IN FIG. 2 was now eliminated, even eters. The revised version I . circuit the leads connect- ng nd condenser should be direct , age plug-in-coil 20-, 40- and 80 r are practically never too y reasonably be made so. itside the tuned circuit are long as the concentrated ity in the condenser are i the distributed L and C eads; all of which usually n l 10 and 80 meters. In fact W—- Av = | FIG CURRENT IN THE TUNED CIRCUIT IS LA ND A RESISTANCE AT R-1 WOULD BE DI BUT THE CURRENT TO THE GRID RESISTANCE AT R-2 DOES LIT- rLE ri. IT HAS BECOME QUITE HIGH IS SM ND ; the tube used ger greater than any practical gl have unless one actually la id along a filament lead or a sl t the only thing a long grid- ea resistance. This resistance pacity of JANUARY, 1928 can be either actual resistance or a poor condenser effect, the latter being impossible if air insulation serves between related leads. As the losses are determined by the simple formula I°R and as the r.f. grid con- trol is largely by voltage with very little current flowing to the grid added loss do not occur importantly with resistances less than 200 ohms, as experiment will prove. See Fig. 4. As the G to F capacity of the tube and the grid-lead to filament-lead ca- pacity can become an important part of the tuned-circuit capacity (see Fig. 5) when the variable condenser capacity is low (so much so as to carry over half the r.f. current within the tuned circuit) a short lead may become important at some dial settings. This fact may account partly for the observation made by myself and some others that a small grid-condenser (which helps to reduce the importance of lead and tube capacity) is of advantage. Experiment shows that this is not a com- plete explanation. The inductance of leads may come into account at very high frequencies. As has been mentioned in other articles in the magazine, a straight wire can act as an r.f. choke. A more practical discussion may be based on the well known circuit of Fig. 6. The outside r.f. leads are drawn heavily and 2 hak Arw “ r ' to. 4 i T t t t ’ s. ‘ soundiacad Turing Capacity, , Tube Capacity between’? Cspacity 2 and grid leads Cot FIG. 5. WHERE THE TUNING CAPACITY IS SMALL THE OTHER CAPACITIES MAY BECOME IMPORTANT This is one reason why it is not advisable to make the tuning capacity very small, for instance less than 25 micromicrofarads. In the diagram if one puts the grid leak and condenser at A the effect may be quite different from that obtained at B, therefore its loca- tion may be important. This is quite noticeable at 5 meters. are numbered. The lead 1 may have im- portant capacity relations to leads 3, 5 or 6. The results in any case are “dead- spots” (due to antenna resonance) even with P and §S loosely coupled. Lead 3 is active to 4, 5 and 6 but the effects to 4 largely may be ignored. The effects to 5 and 6 result in excessive tuning effect from the regeneration control, or in freak tickler sizes, usuallv extra small. Little else is My prefer- likely to result importantly.

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JANUARY, 1928

able arrangement for 4 is not to have this filament lead included in the tuned circuit for there its resistance (not its inductance) can provide an r.f. across its dispropor- tionate to its size. The current within the tuned circuit is at maximum and across

| P Ss |A : (J foe fe it +B— +A- 7 T © FIG. 6. THE RADIO FREQUENCY CIRCUITS, EXCEPTING THE SECONDARY CIRCUIT, ARE HERE NUMBERED FOR DISCUSSION OF THEIR EFFECTS ON EACH OTHER any unit or F in it the voltage drop E is equal to IR. The current outside the tuned circuit should be small so that an E equal to the product of this smaller I with R will be less, so that the voltage above reference of the rotary condenser plates will be the practical minimum. The correct connec- tion is shown in Fig. 3. The d.c. circuit, the filament wiring, of course can be of any length and may be placed any desirable way. The wire need only be sufficiently large to carry the cur- rent since excessive “A” voltage, which we reduce with rheostat, is normal practice. If we carefully terminate our r.f. circuits at the socket terminal F as suggested in Fig. 3 then the filament circuit carried d.c. only and its length is unimportant. The a.f. circuits are those of the phones and B-battery and whatever portion of the A line is included from B minus. These in general in a small one- or two-tube set may be as long or as indifferently arranged as desired. Where in a det.-one-stage job we meet with hand-capacity to the headset the cure is generally a large by-pass condenser across the amplifier B-battery from “B plus” to the detector grid-return whether A plus or minus. The cord of the headset provides a rela- tively large bypass capacity so that its only r.f. has to come from the drop across the resistance of the B’s which resistance is common to detector and amplifier alike. By shorting this resistance with a very low re- actance (1 ufd. or as much as necessarv) the drop “livening” the headset is reduced. In general then it is not short leads that are so necessary as the intelligent placing of leads. T have not yet seriously touched on con- venience or appearance. Under con- venience one example serves to illustrate: OST

I like bare bus-wire because it is rigid and can be soldered to at any point. Under ap- pearance we may consider sub-panel work (which knocks repair convenience into the rough), square-cornered wiring, spaghetti, etcetera, all of which can be used harm- lessly. Admiral Bullard Dies EAR Admiral Wm. H. G. Bullard, U. S. N., retired, chairman of the Federal Radio Commission, died sud- denly in Washington on November 24th, aged nearly 61. His death occurred on the final day but one of the International Radio- telegraph Conference, where he was also an American delegate. He was the second member of the Commission to pass on, Colonel Dillon having preceded him in September. Admiral Bullard was long connected with American radio. He was the first com- mandant at NAA and the first Director of Naval Communications, serving in that office from 1912 to 1916. After duty at sea he agi.in became D.N.C. from 1919 to 1921. He was instrumental in the formation of the Radio Corporation of America as an all-American communications agency which would retain control of American com- municat‘ons within this country. It is fitting at this point to quote an As- sociated Press despatch from Washington: “Admiral Bullard was a great friend of the amateur operators and guarded their com- munication hand with zealous care. To them he attributed much of the progress of radio in America and he often expressed the belief that they would keep this country in the foreground of radio development.” Vale! —K. B. W. aie rae Strays $s Readers are requested to make the fol- lowing correction in the 1927 Index, which was published as a supplement to December OST. Under the head “Amateur Radio Stations” a number of references to page numbers and issves ineorrectly appear as a croup at the end. These references are to editorials bearine unon “Amateur Regula- tions & Legislation” and belong in the sec- ond line of the following section, which bears that title. This index has been furnished without cost to all member-subscribers. Others may obtain a copy upon request.

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Experimenters tel test reports have come »wly indeed and thru sick- » of the men prominent in wrh t We } has become unavoidable ole report over another be realized that this is the last possible moment ich is to say, December Ist. YUENCY TRANSMITTERS requencies from 9XL will were considerably dis- ange of station manage- ut it seems now that Chief ty ley and his crew will be as before with these trans- tion WCCO-9XL-9WI will ; ‘ ( ided before its wholly unique posi- broadcast station, stand- ion and amateur station. good chance that another the winter is is suggested that the of the work of the sta- the standard blanks sup- ection or in the complete the following letter. O.W.L. Radio Station ne-3FC, Queensdale Ave., 6, Oct. 14th, 1927. transmission to-night was ble from the time I reached E.S.T. until 11:50 when you ters with your QST. I after- lulation, but owing to some that time, the music was not ignals were steady R7. At were steady R7 to R&. At ere steady R7 to R&S. At nals were steady R7 to R&. gnals were steady R6 to R7 nals were R7 and still steady tremor was noted. At 11:42 ‘ s signals were R6 to R7 The tremor spoken of before me and fading began to be QST was finished. Signals at fairly regular intervals of modulation seemed to than the c.w. appeared to do, lacy of my ear. When fading r mueie rtion was also quite noticeable, to peak together. modulation now used on to the pure CW used before, , that the pure CW allowed a racy on attaining the true zero The receiver used, by the way il affair with detector and one nna 15 feet high and 30 feet long A you all on your very nice , gly good signal strength as “l work, and more power to timely checks. ist. ACM, Ontario, Central OST JANUARY, 1928 Section Report PROBLEM G-13 IS ALIVE The following letter and circular are a splendid illustration of the way an active problem should be handled. Fairmont, Minn Experimenters’ Section, A.R.R.L. You have at intervals sent me schedules of 5-meter tests, etc. Now I am interested in these things and like to know what is going on but it is a waste of “X" section resources to send that kind of stuff to me as I make no use of it that will ever give the Section returns. I am working on problem G-13 to avoid static and other interference and devote all the time | have to spare on such work to that problem. I do not know if the headquarters gang know that any of the G-13 men are still alive or not but as a matter of fact there are several quite active “static dodgers” hammering away at the so-called Tyzzer System of radio. H. R. Starkey, 153 Cowan Ave., Toronto 3, Ont.., Canada, acts as a sort of correspondence clearing agent for the gang and is building a receiver for the tests we expect to run. H. B. Bennet of Rockford, Ill., is also building a receiving set. Krebs expects to do both xmitting and receiving. He is a navy yard man and has access to plenty of equipment. G. E. Gustofson of Mt. Prospect, Ill., and operator at WJAZ is also expecting to put an xmitter on. His old 9XN equipment is available. Think he is not an “X" section member. There are also a few others interested. I am expecting to put on some tests myself before long. How long depends on amount of time I can spare and number of bugs I have to eliminate. Have xmitter (“one UX-210 power’’) and receiver built and have tested over a few blocks with very good results but have found several of the befor mentioned bugs which have to be picked before trying for longer distance and serviceability data. Expect to run test over a distance of about 120 miles if pos- sible and over a period of time long enough to get data on the system’s possibilities for amateur work. If you have any data along this line or new G-13 men on the list let me know. Also Mr. Tyzzer’s present address if available, also where any information can be had on single side band transmission as it seems to some of us that it could be worked in on the Tyzzer system to advantage J. A. Nightingale, Radio 9ABE, 228 S Fairmont, Minn Main St (We do not know Mr. Tyzzer’s address, having been unable to reach him by mail fer some months. Information will be appreciated. ) A STARKEY BULLETIN The following is a sample of the sori of mimeographed material sent out by Mr. Starkey: Toronto, Ont Canada “Some want circuits, so here are a couple—rather crude but giving the basic circuits without new ideas If you fellows will send in your circuit plans I'l) devote the next bulletin to them so that we may all pick out the ideas we like best in each. Please send complete details, including aerials, power supply, and keying with description of apparatus. The first circuit, using Heising modulation, needs two similar tubes. The 2nd, using grid modulation, could use a smaller tube for the lower frequency. 153 Cowan Ave.,

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il 1928 JANUARY, H. E. Bennett, 1515 Burton St., Rockford, IIl., has come in for the receiving end. Krebs, 3AEA, says he is busy building two navy transmitters, but that when he does get started it won’t take him long to get on the air, as he has al] the necessary “junk’’, Gustafson, WJAZ, says “Will try to make some test next week.”” Fast work ! Nightingale—too busy to report, “I haven’t done a thing but draw and redraw my circuit plans and ‘cuss’ the railroad for non-arrival of my materia! which is following me to Canada by freight.” We seem generally agreed on the 3.5-4 megacyck band, at least until we can put an amplifier betwee W7 y | ?¢ ac oe pate = «= 35m ycle 3s L at (ooh ~~ og AC be « de Om Vater = 14 (> £e0t-——y ~ ) i= | \ J — Le () 2 7 mie b YF e e = ~ Ne = 7. a = : = FIRST TRANSMITTER CIRCUIT” the transmitter and the antenna to pass only one side- band. Are we also agreed on keying in the high frequency to start with? Later, when radiating only one sideband, it will make no difference where we have the key and we can hope to use a modulation frequency in the B.C. band with B.C. receivers for I.F. amplifiers. Don’t be afraid to report no progress. No report no bulletin! WE'’ve got to keep in touch with each other if we want to accomplish anything. If you find it possible—write to all the active men as well four Secretary, Healdon R. Star! CONCERNING TELEVISION There seem to be experimental possi- bilities in the Cooley “rayfoto” method of transmitting pictures. The details are et a7 4 5-METER RECEIVER USED IN THE WGY TESTS Note the general resemblance to the sets used by this section in some of our tests. aS gradually coming forth in a _ series of articles in Radio Broadcast. Unfortunately the series is getting at the principle last, instead of first so that a bit of study will OST 49 be necessary. Who will be first to shoot an amateur picture across the country? Some Special Uses of the UX-222 By Harold P. Westman’ HE object of this work was to obtain a circuit arrangement whereby with a tetrode and a single coil and con- denser not requiring any taps off either, it would be possible to generate oscillations dependent upon the constants of the coil and condenser which could be used for a laboratory oscillator. An indicator of resonance having characteristics closely approaching those of the grid meter in an oscillating circuit employing a triode was also required in order to make the instru- ment capable of competing with such a driver. The output of the oscillator was not considered as a matter of prime im- portance as it was not to be used where high outputs were needed. Figure 1 shows a circuit that will oscil- + e {+4 _ = 6 mils 22.5 volts 45 volts si mils delete left oS FIG. 1. THE B BATTERY TAP IN THIS CIRCUIT IS NOT CRITICAL AND THE TUBE WILL OSCIL- LATE WITH BOTH CLIPS AT +45 The currents change about 5% between the oscillat- ing and non-oscillating condition in all cases. late. It is not known just why this circuit should be able to oscillate as there seems to be no definite feedback paths in the external wiring. It is quite possible that there may be some sort of coupling or an unbalanced condition within the tube itself which accounts for this action. It is, per- haps, due to the “reverse action” of the inner grid current (1.,). The current in this circuit increases as the potential on the outer grid becomes more negative. This is due to the fact that when the outer grid becomes more negative it repels some of the electrons that would normally pass through it and these are then forced back to the inner grid which is positive in re- spect to both the outer grid and the fila- ment. The plate current decreases as the outer grid becomes more negative. As the outer grid is at a radio frequency potential above that of the filament, it can- not be connected back to the filament di- rectly. To prove that the radio frequency choke was not acting as an inductance, causing the three inner electrodes to act *Asst. Technical Editor. :

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50 OST " onnected in an Armstrong cir- Lit ke was substituted for with a res 8,000 ohms. The circuit still co scillate at approximately the sal length though with a decided dr tput. The resistor was of the coat filament type commonly used as 21 , therefore having a negligible N e voltage on the inner grid nor critical and both could be at the tential. That the oscillating ircuit was but a small part T oa { nad ~ j TRANSMITTER USED IN_ TESTS \ Mi ER FROM \ Y, OR RATHER FROM ONE OF THE MA? X—STATIONS AT THAT TEST-POINT. energy was apparent when vere stopped. The currents reuits (not counting filament he ent) inereased by a r cent over their scillations were ed The current d circuit was ap- JANUARY, 1928 as this did not allow these conditions to be indicated on a meter. The meter in the tuned circuit gave the greatest indica- tion but as this was sluggish in action (be- ing a thermogalvanometer) it was by no means a competitor to the sharp, rapid readings that are characteristic of the grid meter on an oscillator employing a triode. Another circuit that can be made to os- cillate is shown in Figure 2. Suppose we were to leave out the outer grid which would then give us a triode. The circuit would not oscillate because while there would be plenty of power available to be fed from the plate to the grid circuit, the phase relation between the two circuits would not be such that the circuit would oscillate. The circuits would not be “pull- ing together” but would be “bucking” each other. Now if we were able to make either the plate current increase when the grid became more negative or else reverse the plate current and still have it decrease when the grid became more negative, we would have reversed the phase relations and this type of coupling would allow the circuit to oscillate. The use of the extra grid allows one of these things to be ac- complished; we can reverse the direction of flow of the plate current. Let’s go back to the triode again. Sup- pose the grid is made positive in respect not only to the filament but also to the 5.5 mils; in the 2 mils, and in the uit, %% mil. The current in the was dependent ratio and is there- ngless unless one the C and L Iso the amount of re 1 the circuit. hat no large current changes t vhen the oscillations started ar made this circuit unsuitable f > Jack for use without Gtr e 100 0. amplifier RECEIVER” plate. That is, the grid is at a higher positive potential than is the plate. Elec trons emitted by the filament will be at-

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ve ns ne ra c- on p- ct he her ec JANUARY, 1928 tracted toward the grid and will attain velocities that are quite high due to the grid being located so close to the filament and there being such a large difference of dk 68mils " £9 25 mils 2.0 - wT Sev 95 vo/ts ' AI fa} ae} afalap-— rr ry. Var 0-200,000.2 ey 2bt 60,000 S$ oan in cect A - + FIG. 2. THE LOWER NUMBERS ARE FOR THE NON-OSCILLATING CONDITION, THE UPPER ONES FOR THE OSCILLATING CONDITION potential between the electrodes. Not all of these electrons are going to be caught by the grid and some, due to their high velocities, are going to slip through its mesh and travel on to the plate. Now when the speed or velocity of the electron is high enough, it may, when it impinges itself upon a piece of metal, liberate from that metal, one or more electrons. These electrons are logically called secondary electrons and the phenomenon, secondary emission. Now, the velocity of the sec- ondary electrons is comparatively low and they will be attracted to the grid which is at a higher positive potential than the plate from which they originated. If the velocity of the initial or primary electrons be great enough to dislodge more than one secondary electron, it is obvious that the plate current will be in a reverse direction to the usual flow. While secondary emis- sion occurs in the usual circuits in which triodes are operated, the plate is always the electrode of the highest positive poten- tial and the secondary electrons are at- tracted back to the electrode from whence they originate making a net gain or loss of zero as far as this secondary emission is concerned. To get back to Figure 2. If the poten- tials applied to the plate and outer grid are properly chosen, the secondary emis- sion can be made large enough to cause the plate current to be reversed and the circuit will oscillate. These voltages must be quite close to the necessary values or no oscillations will be generated. The potential on the outer grid may be left con- stant and by means of a variable resistor in the lead to the plate, the voltage applied to that electrode may be varied until the correct value is found. This value is OST critical and the circuit will not oscillate for any value which gives a reverse plate current but only for values over a limited range. In the particular set-up used, the plate voltage was 56 and the outer grid voltage was 95. The inner grid was re- turned to filament minus. In going from an oscillating to a non- oscillating condition, the currents in the various circuit made these changes; inner grid (grid leak circuit current) from 4 mil to zero; outer grid, from 6.8 mils to 5.9 mils and plate current from .9 to .63 mils (in reverse direction). As the changes in the currents in these circuits did not com- pare favorably with the change that is had in the grid circuit of a triode oscillator, this circuit was also considered as being impractical for the purpose. Re: The International Test Te first International Contest held last May was so successful and so en- thusiastically received that it is being followed by another somewhat similar con- test which is scheduled to open February 6 next. Complete details were given in December QST so that they might be dis- tributed to the most remote parts of the world before the contest opens. Such con- tests have a number of important objectives. They promote international fellowship and goodwill. They create opportunities for making new records. The coming tests in addition offer a chance for you to win valu- able apparatus prizes at the same time you engage in two weeks of rare inter- national sport. Stations at each end of an international contact must help each other in turn with the test messages to add equally to their scores. New friendships will be cemented through the teamwork thus brought about. Every amateur sta- tion in the world is invited to participate. Attention is called to the fact that entries are required of U. S. and Canadian con- testants. The closing date for entries is midnight of February 1, 1928. Before you get next QST the chance to enter in the tests and to become eligible for a prize award will have gone. A QSL-entry-card mailed today will put you in line to receive a set of official test messages and a serial number assignment which will be necessary if you expect to participate. To delay will mean that you may later be denied the op- portunity to enter. Rule 10 (see p. 33 Dec. 1927 QST) will be rigidly enforced as will all the other rules of the contest. Mail that entry card today. We already hear of plans being made in (Continued on page 68)

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ou have had some inquiries P a short-wave station signing If so, you may find the fol- tion to be of interest. ntensely interested in ama- lany years and have been from Australia (oa5MA) n countries. I was finally desire to meet these fel- nally and saw an opportun- ge this desire by signing on \merican barquentine, FE. R. ‘ irgest of her kind in the ‘ loaded with wheat and via Cape Horn. April 16th found me look- watching Australia be- ed blue mass on the horizon. [ had some short-wave equip- th me. The _ transmitter 110 in a Meissner circuit for modulators. Plate 1ined from an Esco dyna- ft a 6-volt storage battery. The he machine was rated at 65 ERLING UPON ARRIVAL AT ST. THOMAS s. An 8-volt battery sup- Besides this trans- main ship’s set, a 1%- quenched spark trans- inch spark coil for emer- tenna had a flat top 140 120 feet above sea level. the best results on the JANUARY, 1928 short-waves. Many others were tried and some brought back quite good reports on signal strength. However, none approached the big antenna~-in the steadiness of the wave during rough weather, and I’m about to tell you that we met some rough weather before we again reached port. “The receiver was a three coil affair with plug-in coils and a switching arrange- aj3ww ment with parallel capacities making it possible to tune from 15 to 20,000 meters. “The trip lasted six months and for five and a half of them we didn’t have a sight of land. You will probably think that during that time I should have been in com munication with land every night. That is just what I expected to do and the reason for thinking so was that I had never been to sea before on a sailing vessel. “After leaving New Zealand, we went south to 52 degrees and encountered south- erly winds. They were so cold that you seemed to be frozen stiff all over, especial- ly the finger tips. Due to this, the exhaust pipe of the gasoline driven lighting plant interested me much more than did the radio installation. It was the only means of heating that was available. “While off Melbourne, the main lighting generator burned out due to high frequency Continued or

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n d e ve ht n is on nt h- yu il- nt lio of ng cy JANUARY, 1928 KFLF, Yacht Ripple. 6BUR Operator. Aug. 10 to October 14. Honolulu thru the south Pacific and return.. All 40-meter. laano lai laj laqp lasf laxx lay] lbhs 1bkp 1b! 1lbqq br Ibze leaa led lfa lve lxv lyb Izh 2aan 2agp 2agw 2ajx 2akv 2al 2anm 2awi 2cuq 2dep 2hh 2ra 2sa 2tp 2uo 3ai 3bqz 3ec 3es 3mb 3pr 3wa 4aba 4acy 4ae fam 4fu 4iq 4js 4km 411 4nq 4pk 4px 4qb 4rm 4rn 4si ttf 4zz Saav 5aaw 5aeec 5aet Safv 5agg BSahp 5aj 5atf avs 5ba See Sct 5dl 5fh Set 5jd 5ke 5ms 5ot 5ql f 5ux 5zav 521 Gaaf Gaak Gabv 6adm Gadv 6agd fagr 6ahe 6ahi 6ahn 6akm 6alz 6am 6amw 6aqm 6avp fay 6bah 6bhaj 6bb 6bbn 6bdw Gbeh 6bhj 6bhq 6bik 6bjh 6bjl 6bjx 6bnk 6bow 6bq 6brd 6buy 6bwk 6bwt 6bxd 6bxi 6ebd 6eer Geda 6efn Gefy 6egn G6chl 6chn 6chs Gechz Gen 6eqa Gere 6ese Gess Geto Geua G6euc bewj fewl 6Geww 6cezf 6dau 6ddo G6dep 6dev 6dfe 6dfm 6dfs 6dfw 6dgy 6djx 6dju 6dkj 6dkx 6dln 6dog 6dph 6fh 6ix 6jn 6ju 6pi 6qi 6rj 6ta 6ty 6ud 6uf 6ve 6xas 6xf 6zd Tabh Tadj Taef Tafs 7agn Talk 7asi 7Tbb Tbhd Tbhq Tbs Tkx 7Tmf Tmo 7mx Tno Tr! nl fdqe 6daq bec ivqa Twe 7xf Sacf Sars Sawe Savp Sbbg S8bjx Sbok Sbxe &Scky Sdjf Sdpa S8eq Seu Sey 8it 8jf 8jq sow spk Spl &sx &sy 9abn Q9adg 9Yadk Q9Yadn Yara Y9aue 1uu Sbex Sbew Sbeb Sbhi 9bmm Ybp! Ybpm Ybtb Ybwn Sbwo Yees Seev Bcjh 9en Y9eoq Ycte GSeww Ycya YIcyp Sezl Sddn 9deq Sdes 9dfz 9dih 9dma 9dmj 9dqn Y%dr Seev 9efk Yep Shp 9kb 9mn Ynz Ysa Ywr oh-6ajl oh-6alm ch-6avl oh-6bdl oh-6boe oh-6buec oh-cxy oh-6dcu wh-6dey oh-6dju oh-6dki oh-6dlr oh-6dph oh-6dpu oh-6n! oh-6wu oz-2al oz-2ap oz-2bg oz-3ac o7z-3af o7z-3ai -3au oz-3vk oz-3xd oz-4am oa-2jw oa-2mh oa-2xi oa-2yi oa-3aw oa-3¢r oa-4go oa-4nw oa-5dx oa-6mu oa-7dx oa-Tpf oo-bam oo-geo oo0-vqlaj op-ldr op-lhr na-7Taea na-T7aeb na-7aer na-wxr ne-4fv ne-5co ne-5go -het nn-Inic nm-9a nr-2fg sa-bd2 ss-2bn en-oja se-2b] jvf myn zbj xrw fop jpp oze gcun jkv xna rbk kdgn kfho kfdu kdkv kudt kzn knt wwdy wnp wwv wvx x8lt oh-fil etTPAR, J. Ziembicki, Lwow, Bielowskiego 6, Poland Ibfx ldz lga lemx lamd Inn lawx laur Inq Ird labz lctw ladn lajx lav! luz laxx lbhm lapv lbms Irx lbwi lxue l1lx lask laac Inx lavj lac lxm laiu lnaao leje lbgt lee Ickk leyx lenk lon ldz lbux lwu lle lbwm Ixv 2em 2uk 2bui 2cuq 2dh 2ctf Zayj 2asg ’evj 2ezr Zahm 2aah 2bum 2bhm 2mb 2akz 2ccu 2baa aer 2cjd 2is 2Zagq 2di 2bir 2az 2tf 2tp 2iz 2xad 2xaf xe 2ich 2atq 2amo 2cyx 2nd 2wy 2bv 2nw 2cx] 2mm afv 2aib 2ar 2amd 2bur Zagn 3pl 3¢p 3ay 3bwt 3kr tiuv 3cw 3ajl 3lw 4ak 4dep 4iz 4fm 4diw 4bx 4dd 4ob jurx 5ad Srh Ssv Ska 8am Sax Salu &bre 9dr 9adk ntt ne-lar ne-Irp ne-2fu nd-hik ne-8rg¢ nj-Sng no-lka np-4k np-4ja np-4sa ng-fex nw-2aqw af-geft ai-di ai-2kw ai-2kx aq-lds ar-S8fbh as-llra fa-Srra fa-8pl fa-Sr¢s fe-2vo fe-egez fi-lta fi-lew fm-8pmr fm-8jo fm-&r¢g fm-Sud fm-Sju fm-8jo fm-Sosp fm-8qq fm-Sgsm fm-Se¢st fm-tun2 fg-pm oa-2md oa-3vp oa-3ww oa-3xo0 oa-5wh oh-laxa oz-laq sa-lpi so-bal a-edl sa-de2 sa-ef2 sa-bb2 sa-hd4 sa-cb8 sa-en8sb-lak b-Ibr sb-law b-lik sb-lic sb-lao sb-lbw_ sb-lap b-lad sb-laf sb-laq sb-lal sb-lai sb-laj sb-lar sb-laz b-lib b-l be b-lbi sb-lbd sb-lqa sb-lem_ sb-ljb b-lah sb-2ay sb-2ag sb-2ax sb-2ad sb-2ia sb-2as sb-2ak sb-2aj sb-2ab sb-2aa sb-2af sb-5aa sb-faa sb-nni b-snf sb-sql sb-sqlq sb-sq4 sc-2aj sc-2ar sc-2as c-2bl se-2ah su-lex su-lwa su-loa su-lbu su-2ak. xen0QQ, in Gulf of Mexico and Atlantic Ocean Gacr Gbpm 6brd G6byz Gbuh G6cel 6elu Geol 6dgy Gdhj Gdha 6daq Ghj 6oe Grn Tagn Tlz Txf ne-2al ne-2bo ne-lar sb-lak sb-lar sb-leg sb-lah sb-law b-las nm-a& nm-xc51 nm-xe53 nr-2fg nn-Inic oh-6dpg oh-fxl1 oa-2hm oa-2uk oa-2rx oa-3al oa-3es oa-3wm oa-4nw oa-5baw oa-5em oa-5dx oa-5sr oa-6mu oa-6gm oa-Thl oa-7ch oaT-cw oz-lao oz-2bp" oz-2me oz-2xa z-3ar oz-4ac oz-4ae oz-4am se-lfg eg-idh eg-5uw eg-6yq ep-lae ek-4ud ek-4uah am-smzf eb-4zz eb-4au eb-4ac eb-4rs eb-4xx eb-4ww ef-Sef ef-8gi ef-fiz ef-8yor ef-Saa ef-Sjf ef-8cp ef-8ku ef-8sm arex ardi ate ajb xed-oik xef-Sarm ee-ear6 ea-gp. nulHV, aboard S.S. Charles Christenson, enroute from San Pedro to Balboa, C. Z. (20 meters) lejh lbyl ldm I1sz 2ctq 2vi 3mb 3mv 3ra 3wb 3agy Sajn Sarx Savb Saxa &brf Scug 8jj 9aal Yara 9bdm 9beq 9bif Sbmx 9bsz Ibtw Ycie Ickq Yemv Yeu Ydke Sdod Sdpw %dws Yeag 9eaj Yenu Yeob 9jm 9md YXph 9vm 6amn 6bq 6cuh ne-3bt sc-3ag wnp ank. (40 meters) lals lbed lenz 1f] Ixv 2afv 2ahb 2aow 2ax 2awi 2exl 2hh 2rd 2tr 2we 2xad 3aks 3bms 3bn 3bqz 3mv 3pr 6adp 6bav 6bpm Gect 6ess 6dfw 6dqq 6det fdky 6dlj 6Geu Tauk 7mt Tsf 7tx 8agq Saip &bki Xboo Sbpa Scau 8&ceq dbs 8eq Sen Shb &Snn 9bbw Sbgq 9bqe Ickv 9em Yen Yepq Ycym Ydfr Odli 9efo 9dmt 9eky 9Yenp 9¢j Dhb 911 9lz 9nk 9nr Yrp Y9xi ne-&r¢g nq-2jt nq-trm nq-5ev nq-7cx ea-gp eb-4ac ef-8dmf ef-8fd ef-8jf ef-Ssm eg-2sz eg-6yq ek-4dba ep-3¢b fqa-pm oa-2dy oa-2mh oa-2rb oa-2re oa-2tm oa-2uk oa-3es oa-5hg oa-7ew oh-6ajl oh-6buc oh-6dlr oz-lap oz-2ac oz-2at oz-2ga oz-3ar oz-4ac oz-4am arcx ardi irfs age tru ocdj ngm nite nwa. 3ANR, A. Sinclair, aboard S.S. H. L. Pratt, anchored off Cienfuegos, Cuba laxm Ichg ickp lyb 2abe 2abf 2aqu 2avl 2awf 2azu 2bda 2bgh 2kl 2vm 3agf 3aso 3iv 4daca 4by 4hy 4nh job 4to 5jy 5nh 5yb 6am 6bpa 6cfr Sakv &bqr &cau Rcejb Sdne Sdnf Sdod Saeo Sama Yasc Sbeq Sbmv Jee! 9dfz 9Yeaj Seld 9eon 9eqq 9kd ne-3ces ne-4ar nr-2ags nr-2ea ef-Sbf eg-5mq eg-6yq sb-2ab aign irl ocdj vjl wnp. 5OX, Robert E. Franklin, 1806 Valentine St., Houston, Texas (Aboard S.S. Olvigore enroute Mediterranean and European ports) laac laba labt lach lads laer laix laj lala lalf lalj lamf lans lanz laqt laqi lasa lavk lavl laxa lbeg lbdx lbez lbhs lbke 1bnl lbsb lbux lbxx Ibvv leaw Icio lej Icjh lemf lemx Ilecra leuve Igp Ikk lmv Imy Ink loi lon Irn Iro lry lud lxaw lyb Izs 2acu 2adl 2aer 2ahf 2ahm 2ak 2alm 2aon 2apd 2apu 2ari 2ase 2asz 2atk 2avge 2Zawu 2ayq 2baa 2buo 2bvd 2bwn 2bxu 2cfg 2cjb 2cjd 2cla 2ctq Zeuq Zevj 2cx! 2gk 2ie 2is 2jk 2jm 2 mb 2md 2ms 2ox 2px 2r 2sc 2tp 2ub 2uo 2wr 2xg 2x] 3abr 3ac 3add 3ahl 3ahp 3ajt 3akw 3bed 3blp 3bms 3cah 3cds 3ce 3ckl 3ee 3fz 3hu 3ie 3jm 30w 3tt 3uy 4br dev 4ea 4ei 4fv the 4hz 4io 4jl 4ki 4mi 4nh 4nn 4doc 4ok 4pk 4rm irn drr 4dsi 4to 4uo 4xe 5aaq 5adt 5afb 5afg 5aop Sapo 5Sata 5aub 5eb 5im 5ke 5kk 5nk 5si 6bzd 6dgy 6hm 6ry Tuj Sade Sadg Saef Safq Sahd Salg Salu Saly Sanh Sasb Sauc Saxa Sbaj Sbau Sbbk &8bf Sbox Sbqi Sbre 8cem S8edb S8ced Sclp S8cor S8erp Sesr 8swb Rdbb S8ddn S8dgp Sdkx S8dmx Seq Sim &lt Snt &8sr &sy Svx 8xe 8zg QYadk Q9aex Yavv She Sbgy Ybnp Ybuz S9bwi 9dle Sdnm 9dr Ydul Yelb Yes 9lz Snr Y9sx Ovo 9xa 9xi ea-gp ea-es eb-d4au eb-4ax eb-4ck eb-4co eb-4ft eb-4uu eb-4ww eb-4dyz eb-7ec eb-k6 eb-k44 eb-n33 eb-08 ee-earl ee-earl8 ee-ear50 ee-ear 59 ef-Saro ef-8brn ef-Sct ef-S8dd ef-8dge ef-Sds ef-8ds ef-Seu ef-Sez ef-Sfiz ef-8fr ef-S8gi ef-Sil ef-8il ef-Six ef-8jf ef-8nox ef-S8sm ef-Sssy ef-8wel ef-Sxv ef-Synb ef-8yor ef-jhp eg-lak eg-2a0 eg-2cc eg-2nh eg-2re eg-5dh eg-6vp ei-ldm ei-lno ei-lIrm ek-4abg ek-d4abf (Continued on page 8&4)

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JANUARY, 1928 a4 OST Correspondence The Publishers of QST assume no responsibility for statements made herein by correspondents. 9) EE ISLL Percentages I know that I did when I let one slip by at . first, and it’s never happened since. Henderson, Ky. Although I am now off the air indefinitely, Bait I’d like to let the gang know just how I \ said concerning the ac- feel about it. I feel cheated after working kK gnals by card but no cne hard to be of service to them. However, ha tistics about it. While | want to thank those fellows who kept the gures are not exactly ex- skeds with me and you may be sure they’ll citing vorth glancing at. hear from me when I set up in the U.S. A. At n out of 685 “nu” stations —Henry P. Karr, ex nzEZ5 wor] 60 QSLed by card. To , gi how the various districts st ter, the percentage of re- Pse ORX ul re as follows: sixth, 74% ; 4114 N. Kedzie Avenue Sev t, 64%; ninth, 637; third, Chicavo. II 61 eighth, 58‘:; fourth, Editor. OST: ies ; a , OST: a ro You may or may not have come across TI plain facts. What say, this new form of super-obnoxious pest who ? ost these averages. The is now darkening the horizon of Hamdom. 0 remember that although This wretch in question after having QSOd tl ugh cards, there are lots with you long enough to acertain your QRA ( anxious to get them and = and get a report on his signals will ask you ( ports in black and white to please QRX for a few seconds while he, o1 colors may be used. presumably, makes some minor changes or I; nany who QSLL toevery- answers a phone call. Blissfully unaware on this wouldn’t be written. of his wiles, you say, “Sure thing ob glad George P. Taylor, 9BAN to QRX.” He then QSYs to another part of the band or perhaps a different one and Pse QSR in fiendish glee begins a CQ to Europe or ‘_— Australia. Btry. 2d U.S.F.A. Btn. The courteous innocent at the other end Gatun, Panama Canal Zone jg still QRXing. After ten minutes or so Edi ; . you begin to wonder, then doubt and finally I" a grudge to get off my — shut down thinking that something has gone cr that some of the gang had at the other end. By running over the h to them, too. It’s about jal, you might find your erstwhile partner S s and the handling of working the same trick a couple of meters m away. wl some of the fellows have My only delight in the matter is in think- ? Why don’t they cut it ing of the everlasting torture that must they can get to those mes- await him after he crosses the River Styx. a many and relayed many Morton Fagen, 9BOA bi ne hung on my hook longer h vorking hours, but it looks , nessages intended for me Bugs al some hooks for twenty- Box 372. Omaha, Neb. fo ender has beat his mes-- fF Jitor, QST: g ind it looks like he will I have been out of the radio game for a Oe fore they catch up with couple of months and just got my receiver h going again the other night. I was greatly I ] of postage money get- surprised and almost horrified at the num- t places I couldn’t get to by ber of poor bug senders on the air. In ee why the other fellow most cases, it sounded like a poorly adjusted e. I have received one thirty that were headed this he others are, I haven’t the | bet someone feels guilty. bug rather than an inability on the part of the manipulator. Perhaps a little informa- tion on the subject of adjusting these bugs for best operation will not be amiss. -

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HAT would happen if your an- tenna ammeter should fail during the February contest? Think of the long nights of vigil, and the many hours of constant service required of this one instrument! Stamina, accuracy, and ability to withstand accidental overloads are highly important considerations if you would avoid anxiety in the crucial test. Why take chances? Make sure that you havethe bestinstruments obtainable. However you decide, do not be misled by superlative statements of perform- ance or unfounded claims. Words are available to all, and imitators usually employ them with rash extravagance. Ifin doubt consult a reliable laboratory. We merely claim the privilege of re- minding you that Thermo-couple type instruments are an original Weston de- velopment, and that other makes are necessarily only imitations. WESTON ELECTRICAL INSTRUMENT CORPORATION 158 Frelinghuysen Ave., WESTON RADIO INSTRUMENTS Newark, N. J. ORV? Say You Saw It In QST—It Identifies You Much depends upon the Instruments you use during the February International Test Model 425 What you will find in Weston Thermo-Milliammeters 1—Definite assurance of your output. 2—Accurate readings after hours of constant service. 3—Extra large overloads will not burn out these meters. They will stand the following currents without damage:— 500 milliampere range—1 Ampere 250 milliampere range—750 M. A. 125 milliampere range—soo M. A. 4— Model 425 is ideal for short wave transmission, as it has a very low in- ternal electrostatic capacity. For this reason it gives the true value of the current in the circuit, and does not disturb the constants of your trans- mitter. Model 425 is made in ranges from 125 M. A. to 20 amperes. Overload capacity of ammeters, from rt to 20 ampere ranges—50%. and Helps QST ammeter

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RADIO PARTS OF Discriminating Set Builders San AS at = mad C1OR) Pa? This { tor 1s scientifically treated to resist t affected by temperature, moisture s the ideal resistance for B-eliminator ng fixed resistors of qual.ty. moistur or age hock iT The racy ohm-E becom ment for volt age leading Use it { your pow provid . leak va with e on your the gr receptior per trol, f place of service. stepless for all tul stats on y learn the Electric Controlling Apparatus MILWAUKEE, S WISCONSIN (AB <<”

I have used a bug on both Morse and Continental and I believe it to be a wonder- ful saver of time, energy and religion but let me say, never try to set a bug for good Morse work and then use it on radio. If you do, chances are that 50% of your dots will not be heard by the other operator. The reason is that for Morse work, a very light dot is required. For radio work, a very heavy dot is necessary. I got the best re- sults from my bug by screwing up the dot contact so that the thing closes after seven or eight dots. That gives a good heavy dot that is easy to read. And another thing, just because you have a bug and like to hear yourself send fast is no reason that the rest of the gang like it. Pull all the weights out to the far end of the bar, buy another one if necessary to slow it down and you will find that QSOs will increase and QTAs will decrease. There is nothing prettier to listen to than good bug sending on a bug set as outlined above but nothing is a greater abomination than the bug sender that thinks he should send at a breakneck speed just because he can. (Half of those fellows can’t do it anyways.) J. H. Platz Appreciation 3086 Eastern Blvd. New York City, N. 1s Editor, QST: I would like to recommend the work of Charles Heiser of 55 Frances Street, Auburn, N. Y. for recognition by the American Radio Relay League. My husband, Donald A. Cadzen, left on June 11th as ethnologist with the Putnam Expedition to Baffin Island. Through the efforts of Mr. Heiser who has been in al- most constant communication with the schooner Morrissey of the expedition, I have been able to keep in touch with Mr. Cadzen practically all summer. Many times, Mr. Heiser has been able to get in contact with the ship when other stations have been unable to hear her sig- nals. He has also relayed some articles from Mr. Putnam for the New York Times. I really believe his work warrants som mention in your magazine, QST. -~Helen H. Cadzen Superheterodyne Newton Center, Mass. Editor, QST: I have been re-reading with interest and appreciation, the several articles which have appeared during the past year on the use of the superheterodyne for high frequency reception. As you know, I use the super- heterodyne exclusively for all my work, from the broadcasting band up to over 20 megacycles, pricipally because it lends it- self so well to metrical work. Using an autodyne oscillator-detector for conversion to intermediate frequency, I Say You Saw It In QST—It Identifies You and Helps QST

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T-2098 Power Supply Transformer T-2098 POWER FOR YOUR 210 TRANSMITTER This Thordarson 130 M.A. power supply unit will operate your 210 Transmitter at full capacity. The excellent filtering improves audibility by “sweeten- ing” your note. This unit when in operation in the 9-J C Transmitter was reported from coast to coast at R-5 with a pure D. C. note. a2 — \O- ——. Ww | 4 2268 [2168 hone fore abe % %y° ™ *) 600k. 600iv 600nv. a ¢ 4 ES5o— _ - T-2098 FULL WAVE RECTIFIER USING FILTER FOR 400 vow TWO 2168 TUBES 1BO MLA RECTIFILD T-2099 Double Choke Unit T-2099 Designed for use in amateur trans- Consists of two individual chokes mission and heavy duty power am- of 30 henries. 130 M.A.. each. De- plifiers using two UX-281 or two Ux-216-B rectifiers. Primary 110- No. ter. 1 signed as filter chokes for power 115 volts 50-60 cycles. Secondary supply transformer T-2098. Chokes 1—550 Neweagl age = of ee mounted in crackle finished com- Secondary No. 2—714 volts, . . . pitas. z Vo pound filled case. Dimensions » amperes center tapped. Second- é rahe fe ~- ary No. 3 same as secondary No.2. 34%” x 4%” x 5%” high. Price Price $20.00, $14.00. NEW JHORDARSON Plate and Filament Transformers A Complete new line of Thordarson long distance transmis- sion equipment has just been released including filament supply, plate supply and microphone transformers and filter reactors for use with all existing transmitting tubes. WRITE FOR YOUR CATALOG TODAY THORDARSON, ELECTRIC MANUFACTURING CO. 4 tC — 1895 WORLDS OLDEST AND LARGEST EXCLUSIVE TRANSFORMER MAKERS Chicago, U.S.A. Say You Saw It In QST--It Identifies You and Helps QST ba | ~]

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West or tenna Seven eled coy maxim be 3=«sétion, great! Ss QOutsid | l4and strand anten Sixt flexibi bron ze to ma A rayo or var wires f elimin easy te set an ance. THI nproves the signal, umeters equal to sizes New Haven, Conn. can buy. isof enam- wire. Presents urface for recep=- corrosion; this We also offer solid and re, and stranded tinned op Antenna Wire f No. 38 bare copper wire for trands of No. 36 phosphor ent stretching. Green or ing; best loop wire possible ble Celatsite Wire tinned copper wires rable Celatsitein- or sub-panel or lilv. Nine sold only in cartons contents. Acme Celatsite Wire ver bus bar hook-up wire nflammable Celatsite in- 1 9 beautiful colors. Strips s readily, won’t crack at 14, 16, 18, 19; 30° lengths. Spaghetti Tubing id proof; hichly dielectric ineers. nine colors, for 18; 30° lengths. (We also s bar, round and square, in Battery Cable | ble of 5.6.7.8 - . Flexible Celatsite ACME ting batteries or | t. Plainly tabbed; , t Giv . 7 = "\\ Send for folder ME WIRE CO., Dept. S 58 J. WIRE {MAKES BETTER RADIO. RT Say You Saw It In QST have repeatedly verified your observation that a more favorable signal noise ratio can be obtained than when the conversion is directly to an audio frequency. But the purpose of this letter is not to discuss this fact, but rather the means by which an audio frequency beat note is produced in the second detector. It would appear from the columns of QST that there is some question whether it is better to use a separate low frequency os- cillator, or allow one of the intermediate stages to oscillate. Most of my experience has been with a completely neutralized in- termediate train, so that I had to use a separate oscillator, but I have recently com- pared the two methods, finding that the separate oscillator is decidedly better. One reason for this is that if the oscillations are produced in the intermediate train there is no easy way to clear the oscillations of harmonics, which for reception of all fre- quencies under three or four megacycles produce an annoying series of “birdies” from end to end of the condenser dial. With a separate oscillator, it is a simple matter to shield, put chokes in the filament and plate leads, and then a simple filter cir- cuit in the output, so that only the funda- mental of the low frequency oscillator is applied to the second detector, and none of the harmonics get into the first detector. Not only do the “chirps” cease, but the self generated noise of the receiver is notice- ably lessened. Greenleat WwW. Pickard Help the Beginner 3 West State Street, Gloversville, N. Y. Editor, QST: seing an ardent reader of the “Cor- respondent” columns of QST, I would like to say a few words about communication between beginners and those who have had more experience. Much of my time has been spent working with new operators and the indifferent attitude of many hams has prompted this short missile. It seems that within the past few months I have been in contact with several be- ginners and with a little patience have been able to carry on some interesting chats. During these chats, they say that they are not getting the amount of fun from their amateur operating that they had antici- pated and upon questioning, one gets an answer similar to this, “Sa ob u r the first ham I hv ever QSO who cared to talk with me.” The reason! Just this, the poor be- ginner has all he can do to receive his ten per and some of them have difficulty in copying at that speed even. The average “speed demon” considers it too much of a bore to carry on a conversation at such slow speeds and considers it to be much greater sport to carry on with someone who can rip it off at twenty-five to thirty words per. About the only thing such men are interested in is the report on their sig- nals and, after that is had, the QSO is fin- It Identifies You and Helps QST

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that maintains constant voltage Raytheon—the one rectifying tube Hl = {Sus TAINED VOLTAGE OVE. R LONG HOURS OF SERVICE t t t — am } t t + + — + t VOLTS | + ; ' = | ; +--+ | | +4 LU — — a tpi rp ef ———~—~+--___ —~ ae & } j POOR se RECERTION ie i | t } ] t | } i se 1 ah i | == 1000 HOURS. “CONTINUOUS SERVICE The reason ? “IONIZED HELIUM” a, Type BH An improved Heav; Dnty Rectifier for radio power service Maintains a constant flow of smooth, silent power, at full voltage throughout its life. Type BH is standard in those units de- signed to supply type 171 Amplifying tube Guaranteed for 1000 hours over a_ period of one year. Rating: 125 m.a. at 300 v. Price $4.50. pully, f Raytheon Long Life Rectifying Tubes have dem- onstrated the advantages of Raytheon’s principle of ionized helium gas over all other methods of current rectification. But the possibilities of this superior principle are almost beyond comprehen- sion. In the Raytheon scientists are Laboratories a continually and further ionized helium gas which will be Research group of discovering new properties capabilities of incorporated in future developments when manufacturers have advanced their products sufficiently to accommo- date them. Today, for receiving complete the simplest and most satisfactory method light-socket operation is the series filament receiver powered by an A-B-C using but tube—the BA. still further advances and Raytheon is ready for them. rectifying Tomorrow power-unit one Raytheon type may see Raytheon Manufacturing Co. Cambridge, Mass. Raytheon LONG LIFE RECTIFYING TUBE Il QF Type BA Only One Tube for Complete Battery Elimination. Due to its unique character- istics, the Raytheon type BA tube, when incorporated in the proper circuit, pro- vides ample and de pe ndable power for receivers employ- ing any number of type 201-A tubes in series. Any battery set can be rewired to operate directly from this one-tube power- unit, Type S eo = noiseless BA—$7.50 Say You Saw It In QST It Identifies You and Helps QST

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Volume Co mpact, go t the thing f controlling ption. Can't detector p r volume an precision to 500,000 knob Amp resistance $1.50! —— eT i oth l-el shell. Dor 285 N. Sixth St. Brooklyn, N. Y. for receiv Precision Resistance at Low Cost ntrol Clarostat “il looking, in- or the receiver regeneration be beat for late voltages eans of matching trans- d other ap- resistance. ohms in le current er appli- adjust- operation. One- Screw ter minals VOLUME CONTROL ©LAROC)STAT Q! i must continue to use | Clarostat for handling hea\ ts, and the Power Claro- stat aviest currents, as here- T ( ostat for every “ham” lake tre, however, you get aa tat—look for distinctive are 1 name CLAROSTAT ’t be fooled, t how to use Clarostats i t if vou want American Mechanical Laboratories, Inc. Variable Resistors Bet | Say You Saw It In QST ished as far as they are concerned. This lets the beginner out. When I first started, I know I had both hands full to get my ten per but I will say that with but very few exceptions all the hams I ever tied in with gave me an even break. I wonder what is responsible fo these changed conditions? We all had to go through the same stages and I suppos« that we just forget for a moment about this. I am sure that the man who now rips it off at thirty per will agree with me that he was no “speed demon” when he made his first QSO. Many of us laugh when we think back of the thrill of the first real QSO that we had. If we would onl) remember that this is the same thrill that the beginner is getting, we would lay aside a little more time for an encouraging chat with him. Is DX more thrilling than a slow, drawn- out QSO with a beginner? Certainly, but remember we are not doing this for our- selves, but for the other fellow who is fol- lowing along in our footsteps. Let’s make it, “One for all and all for one” and give that beginner a little more time than just enough to find out our QRK. What say, OMs? Charles S. Robbins, 8SCRF Another Angle 803 East 7th Street Superior, Wisc. Editor, QST: Sometimes I get so sick and tired when I read of the new hams that say the old timers won’t give them a hand that I want to go out and shoot the works or else blow my fifty. Why? Because the old timers won't help them? No! Because the young squirts have the crust to ask for it. I’ll tell you why. First, when radio was young, or rather when KDKA first started tormenting the ether with strains of heaven- ly (?) music, several fellows came to me and asked me to help them build sets so that they could receive aforesaid music adding that code work might interest them later. I helped them and received a bare thanks. That was all right. Being naturally modest, I didn’t care whether they said thanks or not. I rested peacefully in the thought that radio was to have several more amateurs in a short while. Then, when stations began to be smeared all over the band, my transmitter happened to cause a little disturbance to those re- ceiving near 200-meters. And here came the surprise. These BCLs that I had helped when they were green as grass, were the first to jump on my neck. I shared hours with them and still they kicked. They wrote the Radio In- spector instead of coming to me. They cut down my counterpoise and threatened bodily injury. It identifies You and Helps QST a | du mi: Tu ley ter tiol hav Pri

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oe BEGINNER'S TRANSMITTING TUNED PLATE TRANSMITTER /NDUCTANCES - TUMED CRIO RECEIVING SOWATT SOCKET WAVEMETERS es Se.” INDUCT ANCES RECEIVING COILS There are more REL Transmitting In- ductances in use throughout the world than the combined output of all other Inductance These were the first short wave coils made for the Amateur and are now a part of the noless. receiving equipment in every well known Equip your station with them now. amateur station throughout the world. Double unit—$11.00, complete with glass Wavelength range 15 to 100 meters with coupling rods and 6 clips. 0001 mfd. condenser. Kit includes six Single unit—$5.50 (3 clips) coils with base mounting. Price $6.00. 2 - TRANSMITTING KITS No. 130 RECEIVING KIT Tuned Plate Tuned Grid (pictured), Hart- This was the first Receiving Kit ever ley, M. O. P. A. and Beginner’s Transmit- ter are all noted for their peerless construc- tion and fine performing qualities. We Its popularity is increasing every day. The have a transmitter that will fill your need. Prices on application. produced for the Short Wave enthusiast. price is unusually low at $36.00. REL’s catalogue is something you shouldn’t be without. The stock of complete Dope on S. W. “or what have you” will come in mighty handy many times. Send for your copy today. 25c cash or M. O.—and we keep it up to date for you by issuing timely bulletins. REL owns and operates experimental Station NU2XV on 15.7, 30.2, and 60.4 meters Radio Engineering Laboratories 100 Wilbur Avenue, Long Island City, N. Y. a) © qo000 REL CHOKE CO/L OE FOREST *#* £0 WATT UX-332 SPECIAL SHORT WAVE : “ TUBE HOLDER COUPLED HARTLEY TUBE HOLDER COL AIT Say You Saw It In QST—It Identifies You and Helps QST 61

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RECTOBULBS O ENLARGED FACTORY ha to meet the large demand Re e answer to the plate SUD] SIMPLE—EFFICIENT DUI and LOW PRICED. 10 volt Filar Regular 50 watt) 3000 volts on } 50 Milliamps on plate: 200 full load; a beautiful ‘ob. P 00 each. Na [ype 203 — Guaranteed aga neture. 10 Volt Tungsten Fila 0 Volts on plate 150 mill Price $20.00 each. N Rebuilt tubes—burnt out tube must arded—203 rebuilt . $15.1 ,A with Tungsten Fila- ment 19.00. 204 and 204A with Tung ment $50.00 each. All g pped Express C.O.D. and no crat mn shipments where cash acct ier. We ¢ delivery in perfect condi- tior { Australian and New Zea- lan have arrived in perfect sha We ur products against all defect erial and workmanship and uns peration. Watcl pace next month for an- nour f the New short wave coils plu ealed in tube and evac- uater ted to each ham band—a Little I * for the Ham. NA NAL RADIO TUBE CO. (6EX) 10 18th St. San Francisco, Cal. \ ham_ institution) Still, when anything went wrong with their sets, who did they call for but “the amateur around the corner.” Two faced- And now, when a BCL says that he is interested in learning the code and would like to get into the amateur game here is one brasspounder that looks at him twice and tells him to help himself—I did—and so can they. If he has made an effort to collect the stuff for a transmitter and tries to make it work and can’t, then, and then only, do I offer to help him. Look that over, you new- comers, and still say that the average ama- teur won’t help you get started. You can’t say that amateurs are a snobby lot for they aren’t. If you will subscribe to QST, buy some junk to make a transmitter, I’m will- ing to bet my bottom dollar that the “ama- teur around the corner” will help you get into the game. —Earle Hanson, ex9IBOB Financial Statement Y order of the Board of Directors the following statement of the income and disbursements of the American Radio Relay League for the third quarter of 1927 is published for the information of the membership. K. B. WARNER, Secretary. STATEMENT OF REVENUE AND EXPENSES FOR THE THREE MONTHS ENDED SEPT. 30, 1927. REVENUE Advertising sales, QST $16,473.94 Newsdealer sales ees 11,561.24 Handbook sales ............ 2,540.68 Dues and subscriptions 9,169.37 Back numbers, etic. 442.22 Emblems ..... idea ‘ 214.25 Interest earned, bank deposits 188.65 Cash discounts earned 314.18 Bad debts recovered 30.92 $40,935.45 Deduct: Returns and allowances . +. 4,915.53 Discount 20 for cash ; : 216.20 Exchange and collection charges 41 5,132.14 Net Revenue 35,803.31 EXPENSES Publication expenses, QST wee. 12,659.47 Publication expenses, Handbook $4.00 EEE stavdenyanae cs cndanenie Qe Forwarding expenses 506.46 Telegraph, telephone and postaye 1,821.64 Office supplies and general ex- 2,158.96 REN -ccnetudtonneice at caends Rent, light and heat ........... 922.05 Traveling expenses .......... . 1,778.35 Depreciation of furniture and equip- ment Jiceeuunaeetastbecewes 233.76 Bad debts written off .......... 696.65 Communications Dept. field ex- penses sabenen juveonBeonde 80.36 Total Expenses ....cccees 34,573.10 Net Gain from Operations ........ $ 1,230.21 Additional net gain due to restoration of second litigation expenses in first and quarters, now charged against Surplus ap- propriation Say You Saw It In QST—It Identifies You and Helps QST

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Ouality inte Pattern Instrument No. 190 Panel Mounting A. GC. Voltmeter A. C. Filament Voltmeters Transmitting and receiving tubes using A. C. excited filaments re- quire an accurate means of determining the exact voltage applied to the | filaments. This can best be accomplished by the use of a suitable alternating current voltmeter. For amateur use the Jewell 3-inch instrument Pattern No. 74 has been the favorite for many years, but the advent of alternating current tubes for receiving sets required the development of a smaller instru- ment and which Jewell has provided in their Pattern No. 190, illustrated. | Pattern No. 190 is a flush mounting instrument of the conventional moving vane type with special modification for its small two-inch case. It is accurate and neat, and in general appearance matches the Jewell Pattern No. 135 direct current type. It is designed for continuous serv- | ice and consumes a small amount of current. It is made in ranges of | 0-1.5, 0-3, 0-5, 0-15 and 0-150 volts. The 1.5 volt range is suitable for tubes using directly heated cathode, the 3-volt range is used for tubes having indirectly heated cathodes and the 150 volt range for primary control. The Jewell 15C Radio Instrument Catalog gives a complete descrip- tion of Jewell miniature A.C, instruments. Write for a copy of it. _ Jewell Electrical Instrument Co. 1650 WALNUT ST., + + CHICAGO “*28 Years Making Good Instruments”’ Say You Saw It In QST- It Identifies You and Helps QsT 63

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2 for Wwe ham station: A ont tae} la, 7 ‘

D-Ws ° Proda BS oA vo NS lox Ww »-

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‘Radio a TRA o\ 16S Wi ishington 3 et) - Profess 1S)

AY TNs ow largest concern run by hams the U. S. No delays—prompt y back guarantee. All standard »west prices in the VU, S. ismitting inductance $8. 85 ng rods, complete . eac 3 ttng coil kits . - $9.'5 W Ree ceiving coils | plate and fil. trans-$ $6: .20 v. plate and 7 if nding, mid- tone midtap . ‘ a6.10 veer ) — each AN Some aN * - gs ya mid tap ; ; 816.40 t'g AC or DC voltmeters $5.95 any scale readings . . ysealereading . 89.80 Condensers T 199 .00035 mfd md, T ye B .00018 . $8.90 B .00045 ° 829 Electric 5000 obin 81.45 rd C ent. tap 500 ohm $2 45 iCent tap 5000 ohm 81.80 hm special . 82.20 ED CONDENSERS 500 volt . s _ oy, wae me tH adaded inks vanga ace RIED E rs ire guaranteed Pramas rs will be promptly replaced ETS *Fo 210s, ete. Ge b . ices Ever Sold teas Back Guarantee. Pa LO BNE EOE

ters! Here is Your Book at Last!” (Review, Ist Ed., Q. S. T.) RIMENTAL RADIO HIRD EDITION By R. R. Ramsey, indiana University ires, printed and bound off the press. mmend it very strongly to " (Review 2nd Ed., QST.) experimental manual. “The a text book. It is the best N. Y. Sun. HOW as well as Why ( Oo. D hing Co., 615 E. 3rd Street mington, Indiana

Say You Saw It In QST

REFERENCES and BOOK REVIEWS By R. S. Kruse, Technical Editor

Lefax Radio Handbook revised 1927, by Dr. J. H. Dellinger. Published by Lefax Inc. 9th and Sansom Sts., Philadelphia. Price $3.50 or with one year’s supple mentary leaflets $7.50. Like the preceding editions of this well know reference handbook this particular one is divid into sections marked by heavy pages with index tab with headings such as “What Radio Does,” “Funda- mental Principles,” “Receiving and Transmitting,” “Assembly of Receiving Sets."" The headings a!ready given suggest that the book attempts to cover an enormous territory and must therefore not be ex- pected to be exhaustive in any one field. On the whole the attempt is successful and the information given is concise and useful. One unfortunate excep- tion must be noted. The transmitting circuits ar confusingly drawn and are without exception con- ductively coupled to the antenna in manners not permitted by law in the station of an amateur. Thi is doubtless one of those accidental “carry overs” from an earlier edition such as sometimes escape even the most careful reviewer. Les Ondes Electriques Courtes by Rene Mesny, Professeur d’Hydrographie de la Marine. Published by Les Presses Uni- versitaires De France. Received for re- view through the courtesy of E. M. Zan- donini, Radio Section, Bureau of Standards. It is unfortunate that this book is not printed in English as well as French for we have nothing of the sort insofar as I know. Not only is the general subject of short wave propagation well covered but in addition to this there is material regarding direc- tive transmission with reflectors and with special antennas in which either the horizontal or vertical portion of a bent system is caused to cancel out. There is also a discussion of linear antennas in sev- eral attitudes and the operation of antennas at a harmonic. There is quite a generous amount of material on extremely short waves (below 1 meter) of which the larger part is known to the short wave experimenter but is not ordinarily available in one place. Above all, there is that very important thing, a good bibliography. Everyman’s Guide to Radio, Vol 1, Edited by Raymond Francis Yates, 187 pages, liberally illustrated. Published by Popular Radio Inc. The title page of this book carries a list of 12 “contributors to this volume” and it is presumed that the bulk of the text is supplied by them If this surmise is correct one must credit the editor with a remarkably well unified piece of work for it i no simple trick to combine e writing of different people. Besides this the book i illustrated much more liberally and much better than is the custon so that one does not need to overcome an unpleasant first impression. There does not seem to be any reason why “Everyman’s Guide’ may not become an institution by the comparatively painless process of making additions and changes from the same sources which served so well in this case. It is very probable that this has been in the mind of the editor and that for such a reason he has adopt ed the weird system of labeling the different figures “‘F-3, “1-5,” “NN” and the like, thereby very definitely preventing the reviewer from discovering how many figures there actually are.

The following list of references makes no pretense at completeness but includes sim- ply such material as is encountered through the ordinary activities of this desk. X-ray and Radio Valves, J. Taylor, FE. & W. E. Nov. 1927. The Performance of Valves in Parallel It Identifies You and Heips QST

—_— rho” Lao a. nna

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Dubilier | condenscr | W hat Power Unit are You Building? Dubilier Condenser Blocks for these well-known B and A B C power supplies are all that the care-taking experimenter could ask for in rug- gedness, accuracy, safety and long life. Dubilier Type PL 574 is de- signed especially for the Thordarson R 171 Power Compact, and all You Can’t Build a Better Aerial! So why bother with a troublesome, ex- pensive outdoor antenna? Just con- nect the Dubilier Light Socket Aerial to your set and plug in. All the dis- tance you need, all the volume you want, and clarity that an outdoor aerial can’t touch. Less static, less interference and no lightning hazard. You risk nothing to prove it, for all good dealers sell the Dubilier Light Socket Aerial with a 5-day money-back guarantee. Price $1.50. light-socket devices employing the Ray- theon BH Rectifying Tube. Maximum transformer voltage should not exceed 700. Type PL 575 block is the approved con- denser for Thordarson R 210 Power Com- pact, AmerTran, Samson and all other power supplies using 216 B or 281 type filament rectifiers. Maximum transformer voltage not to exceed 550 V. per plate. Full instructions enclosed. Your dealer has them. Type PL 574—$16.50. Type PL 575—$17.50. A bulletin covering power packs and Con- denser Blocks for every radio need will be sent upon request. Write for it. Dubilier Condenser Corporation 4377 Bronx Blvd. New York, N. Y. Dubilier CONDENSERS Say You Saw It In QST—It Identifies You and Helps QST

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KARAS A-C-FORMER FILAMENT SUPPLY Type 12 LIST PRICE $13.50 NO HUM! lown your 110 volt A. C tandard A. C. tubes house current ‘ such as Cun- Cet without having to use separate de- h ABSOLUTELY NO HUM. Let ment Supply, Type 12, replace your Will operate 8 1% volt Type 22¢ e 227 or 327 Tubes, and 2 5-volt Compact, powerful, sturdy and sion methods. Write for com- ew Karas A-C-Former and also ind Karas 2-Dial Equamatic MARAS ELECTRIC COMPANY 1030 -A North Rockwell St., Chicago X-L Products rrect tube oscillation~more volume and » X-L VARIO DENSER in your circuit. f t Radio Authorities in all lead- ily made issures exact radio frequency circuits, Neutrodyne, Drake Silver's Knockout Capacity Price $1.00 proper grid capacity on Cockaday circuits, ney tuning in super-heterodyne and Capacity range Mid. Model G-5 G-10 .0003 » .001 grid clips $1.50. \ Bakelite Insulated. t insert wire, held Vibra- instantly. Priee panel marked in wiring dia- s in the new pled radio fre- popular hook-ups, ai Detector Circuit, X-L PUSH » stage without POST today BORATORIES, 2428 No. Lincoln Ave., Chicago, Ill. R, P. G. Denman, E. W. & W. E., Nov. 1927. A Plea for Choke Coupling, A. L. M, Sowberry, Wireless World, Nov. 9, 1927. Changes in Frequency Due to Shielding, H. A. Zahl, Radio News, December, 1927, A Versatile Testing Outfit, J. F. Rider, Radio Engineering, Nov. 1927. Theory of Receiving Aerials, F. M. Cole- brook, E. W. & W. E., Nov. 1927. The Telefunken Broadcast Transmitter in Germany (apparatus at all classes of stations) W. Meyer. Same reference as above Transmitting Antennas, M. A. Cremailh (Part 2). Very good discussion of antenna possibilities QST Francais, August 1927. The Horizontal Hertzian Aerial For Transmission, M. G. Scroggie, Experi- mental Wireless, March 1927. Daily Variations In The Heaviside Layer. H. Lassen, Elektr. Nachrt, Tech- nik, July 1927. Approximate Theory of the Flat Pro- jector (Franklin) Aerial used in Marconi Beam systems. J. A. Flemming, Wireless World, July 1927. Automatic Modulation Control In Ger- man Broadcasting Stations, Austria Radio Amateur, July 1927. The Rheinland Sender broadcast station) Austria teur, May 1927. A Study of Coil Resistances at 40 Meters, L. B. Root, general radio experimenter, February, 1927. The making of Paper Condensers, Muter, Radio, July 1927. (50 kilowatt Radio Ama- Articulation Curves, Radio Broadcast, July 1927. Here is a date to paste in your hat! The Third Annual Convention of the Institute of Radio Engineers will be held on Janu- ary 9th, 10th and 11th in tue lobby of the Engineering Societies Building, 33 West 39th Street, New York City. The program will include the installment of the new officers for 1928, presentation of the Liebmann Memorial Prize by Dr. A. Hoyt Taylor, eight technical sessions and some trips. These trips will give all a chance to see the new high power experi- mental transmitter of the Bell Telephone Laboratories at Whippany, N. J., and also the opportunity of going through the new Holland Tunnel under the Hudson River. The other trips will be to WJZ at Bound Brook and to the new Roxy Theatre where demonstration of the making of talking movies will be given. On the last evening, a dinner-dance will be held. All who have attended previous conven- tions of the I. R. E. will want to come to this one and those who have not here- tofore had that pleasure should make sure that they don’t miss it this year. Say You Saw It In QST—It Identifies You and Helps QST num | look you b De: minur estab] nized efs an produ Alu ard b. 2460 (

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of as A. sion ais, For eri- side 2ch- *ro- ‘oni less rer- idio vatt ma- ers, iter, ter, ast, The tute ynu- the Vest 1ent n of and ll a eri- lone also new ver. und here <ing ‘ing, ven- ome ere- sure

ALUMINUM “The mark of Quality in Radio

Aluminum Box Shields Used in the 9. 8. T. December 8S. W. Set OR greater selectivity, finer appearance, amateur sets, are made of heavy Alcoa longer life, lighter weight, use Alumi- Aluminum with satin-dip finish, size 5 in. x tum Box Shields in the set you build—and 9 in. x 6 in. high. They are easily adapted to lok for Aluminum Shielding in the set smaller sizes. They require no soldering. you buy. Three of these standard Alcoa Aluminum box shields are called for in the Q. S. T. Short Wave Set described in the December issue of this magazine. If your dealer cannot supply you with Aluminum Box Shields send us his name and we will see that he is put in position to Designers agree on the superiority of Alu- minum for shielding. It has become an established factor in radio design—recog- nized alike by advanced amateur set build- ersand engineers responsible for commercial production. service you promptly. Be sure to send, also, Aluminum Company of America’s stand- for a copy of the new edition of “Aluminum atd box shields, designed especially for for Radio.” It is free. ALUMINUM COMPANY OF AMERICA 2460 Oliver Building Pittsburgh, Pa.

Say You Saw It In QST—It Identifies You and Helps QST

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ee he Horne of RA 45 VESEY STREET NEW YORK New York's Headquarters for Transmitting Apparatus Full line of Acme -- Thordarson--Jewell Flech- tl » -- General Radio -- Signal -- Bradley SPECIALS ser cap. .000025-10,000 volts $ .45 002 cap. 6,000 working volt 1.95 ed for transmitting 3.45 1¢ I 1 ix 1. \-F transformer 2.45 er Het - et) ™ 2.45 D t nd. tested at 1500V. DC. 1.75 for McCullough A C tubes, 3-3% volts 2 nd. plain or with vernier 1.75 Resistance ped -95 1.10 ‘ N variable cond. .00035 2.95 ‘ Amp tube, complete with nd buzzer 1.95 er. built for 400 v. $10 3.45 ee 2.95 150,000 ohms. all sizes -69 fits standard base 600—900—1200 and 2000 1 sets: very sensitive 3.45 r »-transmitter for 2.45 mounted, all sizes in stock at 1/2 price. IL. ORDE RS FILLED SAME DAY Must Accompany All Orders DEPENDABLE! ws BATIERY POWER! ae 2. ant int irr TT TT 4 if 8 e 4: a VOLT EDISON ELEMENT, NON-DESTRUCTIVE: {ARGEABLE “B” BATTERY WITH CHARGER Shiptr GO Wit WD encecéccecsecass $12.00 140 T Weeee Gee cKocdcocscevcs $17.00 100 1 POWER UNIT with TUBE ...... $16.00 20c. See how it operates. noch down batteries all sizes at REDUCED PRICES NITS built to your specifications. MONEY—PAY EXPRESSMAN r Free Illustrated 24 Page Booklet. SEE JAY BATTERY COMPANY 917 OK AVE. NEW YORK CITY ( Re: The International Tests (Continued from page 51) some quarters for “signing on” a friend as extra op to keep the station on the air more hours per day than otherwise possible. Another individual is scheming to use an automatic transmitter to help him win. A third is entering two stations to better his chances of winning. The opportunities for getting a friend to help as op, for tuning the station to the highest degree of efficiency for different useful waves, for working up schedules in advance of the tests, are equal for everyone or as nearly so as we can make them at any rate. Frankly, we must admit we can’t get the viewpoint of the man who surrounds himself with unfair advantages to assure success. We believe in competing fairly or not at all. Every participant is on his honor as a gentleman to abide by the spirit as well as the letter of the rules of the contest. The award committee (representatives of several departments of Headquarters will be asked to serve on this) may also consider itself appointed to consider any irregularities and rule if they are un- ethical or unfair should occasion require a ruling. This committee on irregularities may set up any general policies it deems necessary in carrying out its work, basing these on the rules and printed announce- ments of the contest of course. It is neces- sary to draw the line somewhere to protect the interests of the average station owner who takes part in the contest—hence the committee on irregularities. This commit- tee will consider any complaints brought to its attention and investigate if necessary. It will be assisted by a staff of specially qualified observers in different locations who will be selected and appointed just before the beginning of the contest. These ob- servers will be non-participants on observ- ing duty for the period of the tests. Three or more independent reports of off-wave operation (or other irregularities) from reliable sources may be accepted by the com- mittee as sufficient to disqualify any par- ticipant. In other matters than off-wave operation, the committee shall have power to decide whether the penalty for irregu- larities shall be loss of points or disquali- fication depending on the evidence submit- ted. The active functioning of this com- mittee and its observers will be even more important than during the last tests when the need for such a committee was shown due to the fact that there are prize awards involved in the decisions this time. Enough about the award and irregularities com- mittee—remember all the rules and watch your step! If a station shall be heard making sched- ules for another station for the purpose of handling test messages during the contest this shall be considered unsportsmanlike. This station shall be reported by whom-so- ever shall hear it and shall be penalized to the extent of losing all points that it is Say You Saw It In QST—It Identifies You and Helps QST

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RADIO FREQUENCY AMMETERS FRONT OF PANEL FLUSH MOUNTING Since the hot-wire type meter is independent of frequency it may be used for any purpose in the transmitter from radiation ammeter to regulating the battery charging rate. The 127 line of meters is supplied in front of panel and flush mounting, and portable types. Ranges — 100 milliamperes (full scale) to 10 amperes (full scale) BREE cn cckcuccanonsnct $7.25 to $10.00 GENERAL RADIO CO. 30 State Street Cambridge, Mass. A. R. R. L. MEMBERS ATTENTION! You are not all located within shopping distance of a dealer stocking G. R. parts. Remember that we will deliver, postpaid, anywhere in United States any of our radio parts on receipt of current catalog price. Also we welcome your correspondence. Have you Bulletin 928 in your files? If not a postcard will bring it. Say You Saw It In QST—It Identifies You and Helps QST

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PARVOLT: ormerly Sangamo WOUND CONDENSERS | Stan ne Surges ( apacities and prices A Series B Duty Mfds 800 Volt Duty | $1.25 2 50 5 00 50 50 1.0 2.0 4.0 We Recommend wrtdoe ir) So So Sangamo Mica Condensers THE ACME WIRE COMPANY New Haven Connecticut 7. Centralab a knock-out for warp-proof, ce. Its construction permits at temperatures of 482° F. tance wire is wound on metal ated: core expands with wire, on. Narrow resistance strips ance jumps per turn, further reculation. Compact 2” di- , 250, 150, 50, 15, 6, 3, .2, .56— also be furnished as a poten- ealer’s, or C. O. D. You need this Rheostat. Send postal for new cir- CENTRAL RADIO LABORATORIES 29 Keefe Avenue Power Rheostal apparent were gained through such collu- sion or unfair assistance or the station may be entirely disqualified at the discretion of the committee on infractions. If any U.S. or Canadian entrant shall accept and tender for credit reply test messages totalling more than 5% of the whole number of mes- sages originated bearing the official serial number of one particular entrant, this shall be considered prima facie evidence of either the operation of agreements between con- testants or at any rate of unfair means of point-winning thru closely following the operations of particular contestants to too great an extent. Suitable penalties shall be prescribed by the award committee. The figure given (5%) is based on a considera- tion of reports submitted in our last con- test. We must point out that it is equally fair to all and that it is simply designed to provide a penalty for unfair collabora- tion between stations. The committee shall view the logs and all evidence for and against and be the sole judge as to whether collusion exists, providing suitable penalty therefor. As a final suggestion to the U. S. and Canadian entrants—don’t forget to look for the “np” and “oh” stations right in the U. S. band. They are competing with the outside world even though licensed in U. S. bands. The “eg’s” on 23, 45, and 90 meters should not be neglected either. —F. E. H. Municipal Ordinances on Radio Transmission Unlawful (Continued from page 26) States. And Congress has covered the field by appropriate legislation. It follows that the ordinance is void as a regulation of in- terstate commerce. : “The motion to dismiss is overruled. A. M. J. Cochran, Judge.” We hope everybody realizes to the fullest extent just what this means. Where other local ordinances already exist, we now have the most clean-cut kind of precedent to cite in seeking an injunction. What is more im- portant, however, is that it is extremely unlikely if any city will attempt to pass such an ordinance, with the above in mind. The city-ordinance danger no longer exists as a menace to amateur operation. It is most unfortunate that space will not permit the inclusion of Director Segal’s brief in the case. It required a tremendous amount of work and research. It was a great case, a masterly and air-tight job, and the amateur fraternity will be forever indebted to him for it. Say You Saw It In QST—It Identifies You and Helps QST Stre

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id at a Cross section of Cone showing grad- 9) uated diaphragm. Cone Speaker which Faithfully Portrays a Stromberg-Carlsons Tone Toe correct proportioning of the size and shape of the cone, the new Stromberg - Carlson Speakers are able to reproduce exactly every note and vibration sent to them from the scientifically ad- eigen ely’ = justed Stromberg-Carlson Receivers. Esstof Rockies . . . $40. o a Rockiesand West . . . 44. Theapex {center } of the cone is thinner than the outside Eastern Canada.” .” .” 50.00 edge, gradually increasing in thickness from the center to the Cem .. . OS outer rim. This thinning of the“radiator”at the center makes possible accurate reproduction of the higher frequencies, while the rest of the cone gives a faithful portrayal of the . . . . . ity low and intervening frequencies. The objectionable “paper ee a ae rattle” usually found in large cones is eliminated by this No. 10, but Wall Type. Price, graduation of the cone thickness. qnct hetie . - $35.00 . 1 ° ° . a Fashioned of tough paper fibres, gathered on a cone shaped Eastern Canada. . . 45.00 form there is no grain or seam, thus insuring uniformity of ae oe tone and great durability. Another feature of these excep- tional Speakers is the specially designed “baffle board” placed on the back so as to prevent rattling and resonating at the lower frequencies. No. 523 Seromberg-Carlson as Stromberg-Carlson Cone Speakers are built expressly for use —_— Uendahon te with Stromberg-Carlson Receivers. Their Superior reproduc- but not including Cone Speaker, ing qualities will, however, greatly improve the reception East of Rockies . . . $295.00 from any other high class Receiver of the same power. Rockies and West . . 315.00 Eastern Canada . . . 390.00 Stromberg-Carlson Telephone Mfg. Co., Rochester, N.Y. Western Canada . . . 400.00 Stromber¢-Carlson Makers of voice transmission end voice reception apparatus for more than 30 years Say You Saw It In QST—It Identifies You and Helps QST 71

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FROST- RADIO FROST RADIO FROST-RADIO FROST-RADIO i : FROST-RADIO OFFERS @.S.T. READERS TWO VAL- YABLE NEW BOOKLETS FREE! | a Wh Write For Them readers of Q.S.T. two valuable new blications free on request: ‘“What the answer to a question which builders, and the new Frost booklet Reception.” a complete and helpful t waste Every set builder should vwoklets They will be found nfe mation that is right up to the They Contain Mail Coupon NOW! I Shall To secure these two book- ‘bout jets FREE fill out and “F - mail coupon below, print- tells ing your name and ad- stat dress carefully. These has books will amaze you r high with their completeness. and Po — Write for them to-day— NOW. HERBE ERT H. FROST, Inc. Main Ch HERRE rT. A Office and Factory, Elkhart, Indiana icago New York H. FROST, In a Salle Street, ‘Chicago ir two booklets, as advertised in Serre eee eee eee eee eee eee ee PP eee COSCO CSET O COSCO eT eee) | 4soul Oravil-isoud Ofdvl.1soud Olav -isoud O1avl-isoud Olavil-isoud FROST-RADIO FROST- RADIO FROST-RADIO FROST-RADIO FROST: ~] i) ‘\ RADIO Re quires NO attention. Over 1000 now in use. |INTERFERENCE FILTERS Take out in noises your radio caused by motors and household appliances. ze No. 1 for small motors, $10 Up to 1-4 b.p. e No. 2 for larger equipment Up to54.p.@ 220 volts $15 WRITE FOR PRICE LIST OBE DEUTSCHMANN CO. CAMBRIDGE, MASS, I. A. R. U. News (Continued from page 52) energy from the radio transmitter getting into it. An electric motor was encouraged to act as a generator after some of the field turns had been removed. It was belt driven from the flywheel of the gas engine and had to travel at 3,000 revs per minute in order to deliver enough power. During bad weather that belt played all sorts of tricks and power for charging batteries was strictly limited. While I could not be on the air very often at this time, some fine contacts were made when we _ reached warmer and finer weather. While off New Zealand, nc4FZ was worked. This was the best DX while at sea. After leaving New Zealand waters, all short-wave signals became weak, even WIZ. However, on 600-meters several California coast stations were copied. Gradually, amateurs in Chile, Brazil Uruguay and Argentina were worked and while off Cape Horn the sea became as calm as a mill pond. “A few days after sailing clear of the dense ice fields off the Falkland Islands, we were struck by a fierce squally gale which in a few minutes carried off our main mast and, half an hour later, the mizzen mast also crashed to the deck. Both masts trailed over our starboard side held by the wire and rope rigging. They struck the rudder several times with great force before we were able to cut them adrift. “After the gale moderated, the ship was once more headed toward Europe, now under jury rig, four masts remaining. A new antenna was erected and the weather conditions improved as we reached the tropics. While still a few hundred miles from the equator and only four hundred miles from the nearest coast station (Per- nambuco, Brazil), I tried for hours to push through news of the accident. Fierce static made this impossible and I tuned up the 7% watter and with 35 watts input sent the news via nu2RS and nu8DLD without any difficulty. Many other stations also handled our traffic and I wish to thank them right here for the kind codperation. “On September 4th at 2 a. m., ship’s time, I was QSO nu8DLD on schedule and told him I would have to QRT as it was getting too rough to work. So I closed down and turned in until 4 o’clock when I was awakened. The ship was in a roaring hur- ricane. When I reached the deck, there was wreckage everywhere and shreds of sail were whistling and flapping in the wind. At about 7 a.m., the large steel foremast with its six square yards of can- vas crashed to the deck and the mountain- ous seas took charge of the ship. Ven- tilators, pumps and light woodwork were washed off flush with the deck. Leaving us a pitiful wreck, the hurricane subsided shortly after eight o’clock. “The chief mate who was in a serious condition was carried to the after cabin where he died not long after. Say You Saw It In QST—It Identifies You and Helps QST

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d It e £ rf e ie wv 1e y, id QST BINDERS You'll NEED ONE of these for your 1927 copies of QST and some for your previous volumes, too Maroon Buckram with title stamped in pure gold Just fits twelve issues of QST SENT POSTPAID 50 =—=eCa. Get a set to hold all your back is- sues of QST—you know they de- serve permanent preservation Note the wire fasteners. QST Unnecessary to mutilate 1711 PARK ST., copies. Opens and lies flat in any position. HARTFORD, CONN. Say You Saw It In QST—It Identifies You and Helps QST

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Quality Amateur Apparatus Laboratory Products are Q t for Transmission and Re- \ supply Transmitters for R r C. W. Receivers of the rht Tube Designs with Wave- from 15 to 210 Meters. Our S fiers are supplied for Direct Control. We also make and eters, Inductances, Choke ( Distributors for Nationally phones, Transformers, Plate

| Motor Generators, etc. We r using your parts if desired. P \ pplication. ENSALL RADIO LABORATORY 1208 Grandview Ave. Warren, Ohio Ama Broadcast Marine ‘Pion Builders of Short Wave Apparatus”

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Say You Saw It In QST—It Identifies You and Helps QST “Only the center mast now being in com. mission, we more drifted than sailed and six weeks later we reached Sombrero Island light (about 130 miles East of Porto Rico) where the U.S.S. Grebe who had been sent by the St. Thomas naval authorities found us and towed us to St. Thomas (Virgin Islands). I have certainly been cordially treated by the two amateurs on the island np4AAN and np4ACF. “At the time of writing this, we are still at St. Thomas awaiting the arrival of a tug which is to tow us to England. I have hopes of again QSOing the gang while on the way over and believe this part of our trip will be less exciting than that already over.” —M. B. Anderson, WIS. JAPAN The Japanese amateurs have at last won the right to build and operate amateur experimental stations. The government has recognized the amateur to the extent of granting licenses for such stations. The only wavelength on which transmis- sion can take place is 38 meters. No other waves can be used. The maximum power output is 10 watts and some licenses allow only 4 watts output. This will most prob- ably not be considered as a handicap as many of the stations now in existence are using powers of this magnitude. As all communication in Japan is man- aged by the government, these private ex- perimental stations are strictly prohibited from handling messages and also from “chewing the rag”. Stations are allowed to communicate with each other only about matters necessary to the conducting of ex- periments and a report on each and every such communication must be sent in to the government official who handles this matter. However, all the licensed stations will be glad to get into experimental com- munication with amateurs in other parts of the world. The call letters assigned to these sta- tions will be four lettered ones. The calls already issued are listed herewith and it will be noted that so far, three of the letters are the same for all calls, but one letter being changed to make the calls different. JXAX Kankichi Kusama, Hirano, Mika- gecho near Kobe. JXBX — Semba, 1-3 Sugamo, To- yo. JXCX Noboru Eimura, 1102 Hirazuka, Tokyo. JXDX Shiro Akuzawa, 25 Maebashi. JXEX Hauro Horikita, 957 Shimohebi- kubo, Ebara, Tokyo. JZXFX Momoki Sumi, 1401 Shimo-shi- buya, Tokyo. Nakanobu Tatemachi, JXGX Toshio Seki, 33 Sakusabe, Tsu- gamura, Chibaken. JXHX Hikotaro Takeuchi, 419 Ikebu- kuro, Tokyo. _ There are four other licensed stations in Japan concerning which we have some in-

ae

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On) - and and ico) sent und ‘gin ally and till oa ave on yur idy n- 1- ls it ' In September we published this advertisement: $4 Worth of Book for $ | OMEBODY got to figuring not long ago and made some interest- ing discoveries about THE RADIO AMATEUR’S HANDBOOK. They show what we mean when we say the Handbook is the biggest dollar’s worth of radio literature ever offered. This Handbook is not printed in the fashion of an ordinary book. Books are printed in relatively large type, lines clear across the page, space between lines. We found it more convenient to print the Handbook after the fashion of QST—the same size page, the same size type, and the same two columns to the page. The result is that the Handbook has that same often-unrealized quality of QST—it has an astonishing number of words between its covers. It runs three times as many words to the page asean ordinary book. If printed after the ordinary fashion of books, the Handbook would have over 500 pages! Let’; get a complete comparison. Everybody knows Ballantine’s “Radio Telephony for Amateurs”, universally admitted to be an ex- tremely valuable book for every amateur. The A.R.R.L. Handbook, “The Radio Amateur’s Handbook”, has nearly twice as many words as Ballantine! Is Ballantine worth its $2? You know it is. Is Ballantine profusely illustrated? The Handbook has thirty more illustrations in it than Ballantine. If the Handbook had been produced like an ordinary book it couldn’t have been sold for less than $4. Now you know what we mean when we say the Handbook will represent the best dollar you ever spent. “THE RADIO AMATEUR’S HANDBOOK” A Manual of Amateur Short-Wave Radiotelegraphic Communication By F. E. Handy, A.R.R.L. Communications Manager Price $1 Postpaid Anywhere Published by American Radio Relay League, : Hartford. Conn. —and now the new, revised, 3rd edition, 32 pages larger and up-to-the-minute, is available! —EE — —— em i i — ——— — —__—— ———— Say You Saw It In QST—It Identifies You and Helps QST

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76 SANGAMO AUDIO TRANSFORMERS <<

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Sangamo Mica Condensers re accurate and stay accurate. GAMO ELECTRIC CO., Springfield, Ill.

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formation. JKZB is a purely experimental station controlled by Y. Imaoka who is on the research staff of the Tokyo Electric Company. It is located at Kawasaki. JLZB is the station of T. Kusumoto, 38256 Kakomi, Nakano, Tokyo. We believed this station to be doing amateur work but find out that it is operated by a govern- ment agent for the purpose of obtaining in- formation concerning unlawful operation of stations. We believe the same thing to be true of JMPB which is run by T. Kokumai, 1242 Nakameguro, Meguro, Ebara, Tokyo. The same may be true of JLYB, I. Arisaka, 84 Kami-Umahikizawa, Komazawa, Ebara, Tokyo although we have no definite information concerning the status of this station. All the owners of the licensed amateur stations are members of the Japanese Amateur Radio League and all letters for them or other Japanese amateurs may be addressed to the League, 1-3 Sugamo, Tokyo, Japan. We are showing a view of aj3WW but unfortunately were unable to get any in- formation as to just what all his equip- ment is. The station is located near Kobe and has done some excellent work. AUSTRIA “The Austrian transmitters are still un- licensed but notwithstanding this fact, the number of transmitting amateurs is in- creasing every day. Many of these are now in every night contact with all continents, the conditions for making contacts being very good just now, especially with the United States, Australia and Brazil. “The official QSL service is now handling a large number of reports and the ten thou- sandth card has been received recently. All cards should be sent under cover to Radiowelt, Wien III, Rudengasse 11, Vienna, Austria. “Many of our stations working on 45, 32 and 22 meters would like to obtain schedules with nu stations. Any nu stations inter- ested in these schedules should write to the above address concerning them. Receiving conditions are improving every day and many nu stations are to be heard with signal strengths varying from R5 to R9. “O9XAF is still our favorite short-wave broadeast station and may be received on three valves with loudspeaker strength ’most every night. Very little fading is noticed.” —Th. Mossig, eaAC. BELGIUM “Although the 40-meter bands_ get crowded each autumn, it seems to be even more crowded this year than any before. This, in spite of the fact that many of our best stations are working in the 20- and 32-meter bands; is due to a large extent to the many phone stations that have come down to this wave. It seems to be very much more difficult io keep within the ama- teur laws, two or three phone stations than a hundred key punchers. Say You Saw It In QST—It Identifies You and Helps QST

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EVERY TRANSMITTING AMATEUR USES THESE FORMS —a reminder that your supply may be low— AMERICAN RADIO RELAY LEAGUE Sweet No. aif $ LOG OF STATION coumerjes| ... a. | enna Members’ Correspondence Stationery Write your radio letters on League letter-heads—it identifies you with the biggest radio organization in the world. Lithographed on 8% x 11 heavy bond paper. 100 sheets post- paid for 75¢ or 250 sheets for $1.70. Sold to members only. 4 RADIOGRAM 4% TST == | Message Delivery Cards Neatest, simplest way to deliver a message to a near-by town. On U.S. stamped postals 2c each. On plain cards (for Canada, etc.) 1c each post- paid, A.R.R.L. Log Sheets Designed by hams for hams. 8% x 11 bond paper, punched for standard three-ring loose-leaf binder. 125 sheets postpaid for $1.00 or 500 for $3.50. Official A.R.R.L. Message Blanks Most convenient form. Designed by the Communications Department of the A.R.R.L. Well printed on good bond paper. Size 8% x 7%. Put up in pads of 100 sheets. One pad postpaid for 35c or three pads for $1.00. RADIOGRAM Ss —s ~ ~ gre wae oo Ee Pe ee American Radio Relay League 1711 Park Street Hartford, Corn. Say You Saw It In QST—It Identifies You and Helps QSsT

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4 LAST ONDENSER. m ,QORRE IIS Wew

ebiFT grid circuit tuned. The plate input is be- tween 100 and 150 watts and the potential is 1500 volts which is obtained from an Esco motor-generator set. A _ fifty-henry choke and two mikes of capacity comprise the filter. A single wire horizontal aerial and counterpoise are tésed. All continents have been worked. The receiver is of the plug-in coil variety using a capacity con- trol of regeneration. One stage of audio amplification is employed. HUNGARY “The so called ‘Act of Short Waves’ per- mits amateur transmission under regula- tions that are quite similar to those in force in England. Probably the best of the legally operated stations is ewH4 who has made many contacts with nu stations. “We find that a large number of Ameri- can stations send at a rate that is beyond our ability to copy and we must, therefore, forego the pleasure of working them. It must be remembered that we are just start- ing in with the handling of the Morse code and have still to obtain our experience. So far, we have had to be content with doing most of our work with other European amateurs. “By no means all of our transmitters are licensed. There is a large number that are working under cover and every day we receive from sixty to eighty QSL cards for You Saw It In QST—It Identifies You and Helps QST

eee SS ) ne SS eh e a~ GS 63 bS hs

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n 5- ting our L923 ince 27 U- the 1 in (old and -on- int- les. of . is lge. y of ele- ger lo- 3. nan ves the be- ial an ry ise ial its he yn- lio Tl - a- ce he as ri- id 2, It t- le Faithful Service The function of a power resistance is to control voltage and current accurately — permanently — silently. AEROVOX PYROHMS used with GOOD equipment make a BETTER power unit. AEROVOX PYROHMS are built to last —are used by more than 20 leading power unit manufacturers.— This is conclusive evidénce of their reliability accuracy — worthiness. Made in all values of resistance for continuous duty at 20, 40, 100 and 200 watts. EROVOX “Built Better” 70 Washington St., Brooklyn, N. Y. GROSS SHORT WAVE LOW LOSS “PLUG-IN” COILS The coils you will eventually use. Wound with sufficient range to overlap with the next smaller number 16 double silk covered wire with turns and larger coil. There is one for each amateur spaced the diameter of a turn. It is a recognized waveband and it can be plugged in and out as fact that the space wound solenoid is the most easily as a pair of phones. efficient form of inductance. The distributed The base which contains the jacks, also holds capacity is at a f the antenna coil on minimum and die- | a small swinging lectric losses are \ arm, which permits too low to be meas- | all degrees of coup- urable! An extremely thin film which the t very bottom, is the binder which serves to ma ruggec wound form. nating dope of any kind is applied to the winding The Price of coils only: ding. winding is extreme- 20meterband $2.75 ly rigid and may be 40meterband 2.75 rraspe il ir = poe the oot anne 80meterband 2.75 e é . Each of these 200meterband 2.75 coils will cover a 600-200meters 3.25 GROSS RECEIVER KITS Gross Transmitter Kits, Tuned Grid, Tuned Plat Composed of high grade material throughout 744 Ww : ben , nec cccQetene 2 Tube Kit... .-.sseecerseesecceeceseseses $15.75 i errr véusaniesasenee 2 Tube Assembled Receiver ...........cceeees 18.00 é ve 3 Tube Kit Lesnéaneetsenesas 18.75 Transmitting Inductances, Tuned Grid, Tuned 3 Tube Assembled Receiver ................ 21.00 Plate $8.75 wound with copper Tubing 20, 40 or Above Receivers or Kits supplic d with one plug 80 meter bands. in coil for 20, 40 or 80 meters, as you select. Send stamp for circulars describing full line of Extra coils $2.75 each. S. W. transmitting and receiving apparatus. GROSS COILS ! ling from zero to 100. These coils will unquestionably im- prove the appear- ance and operation of any short wave receiver. | of celluloid | only touches urns at the ke this coil as las if it were on a_ solid No impreg- Price of base with coil for one band, $4.50 Dealers and Representatives Wanted. Write for discounts. J. GROSS COMPANY, 27 se Pes: Say You Saw It In QST—It Identifies You and Helps QST

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QUALITY | CED) PRODUCTS Now That Everybody Demands Electrically-Operated Radios Dongan Is in Production on All Types Here Is the Newest No. 6515 Transformer for use with 4 UX 226 1 UY 227 AC Tubes and 1 UX 171 Tube. Together with a B Eliminator, this new transformer will convert old type set “| 5 into an_ efficiently $22 List operating A C set. A B Unit for l A Unit for $4.75 List = ; This is one of 14 types ranging in price Or r dealer from $3.50 to $8.00 or r money for use with the new lirect. types of A C Tubes. Dongan Electric Manufacturing Co. 2999-3001 Franklin St., Detroit, Mich. SS 7. 7 we) \\ TRANSFE ORMEPS of MERIT for FIFTEEN YEARS ?». No. 5553 FLECHTHEIM Superior Condensers For Amateur Stations BY-PASS FILTER BUFFER HIGH TENSION TRANSMITTING All Standard Sizes Accurate capacity rating Dependable for continuous duty Write for Catalogue A. M. FLECHTHEIM & CO., Inc. Dept. QT 136 Liberty St. New York, N. Y. BECOMEA RADIO OPERATOR See the World. Earn a Good Income Duties Light and Fascinating. LEARN IN THE SECOND PORT U.S.A. R re. New Orleans supplies oper- ‘ r Most logical location in training Pr fr perators graduating on the Quit e years trained by MR. CLEM- MONS Instruction All graduates secure ieee R.L.—Call “5 G R” Enroll anytime—Write for cir- GULF RADIO SCHOOL 844 Howard Ave. New Orleans, La. Say You Saw It In QST—It Identifies You and Helps QST them. These are, of course, all sent under cover or else these stations would be getting into difficulties with the authorities. There are also many who will not take the risk of being caught while operating an un- licensed transmitter and who have devoted all their energy to the matter of reception. “T understand that there are now about fifty who have petitioned the Government for licenses and it is thought that all will receive them.” —F’. Molnar. (It is not definitely known why these “under cover” stations do not obtain licenses but it is probably due to the lack of neces- sary funds.—Assist. Tech. Ed.) SOUTH AFRICA We are showing a view of foA4L, the sta- tion of Robert Oxenham who used to sup- ply us with our South African news each month. On the right, mounted to the wall, is the transmitter which employs a Mullard 0/150 tube. Plate supply is obtained from a motor-generator which applies 1400 volts to the tube. The input is usually 100 watts although the tube is rated at 150 watts. The filament is supplied from a storage battery which may help account for the many crystal control reports received. In the center is the short-wave re- ceiver of the “Reinartz” type covering all the amateur waves down to ten meters. The detector tube is a B. T. H. (for the manufacturer’s name, British Thompson- Houston Co., Ltd.) power tube which seems to work best with two volts on the filament and nine volts on the plate. A wavemeter and a broadcast receiver comprise the other equipment on the table. A4L is a member of the WAC club and has made an enviable reputation not only on the air but as one of QST’s most con- sistent correspondents during that time when he was detailed by the S.A.R.R.L. to keep us informed as to the doings of our South African friends. As the result of a vote of the I.A.R.U. members in Australia, the Wireless Insti- tute of Australia has been designated as the National Section of the Union in Aus- tralia. Much credit for the successful negotia- tions resulting in this step is due to the

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GET TRUE MUSICAL RECEPTION TIMMONS Combination Power Amplifier and “B” Supply 7220 SPECIAL $23 TIMMONS Power Amplifier peex us sssco SPECIAL *15= Both of these high quality compact units “B” current required by the regular tubes use a U.X. 216B or 281 tube for rectifying of the set. No adjustments required and and a U.X. 210 super power audio tube 0 output transformer or similar auxil- as an amplifier which gives distortionless ary equipment needed with either unit. and true natural reception with wonder- A oer ~~ ataaaae current 105-120 ful tone quality and volume. volts, o0- 7 yee. : a , j : Every unit is brand new, packed in Both instruments are identical in their original factory sealed carton and fully performance as super power amplifiers. guaranteed. They have been approved The Combination however is also a com- by Popular Radio and Popular Science plete “B” Eliminator furnishing all the Laboratories. AMERICAN SALES CO., 21 Warren St., New York City h : Item 37, 2 unit four bearing set, delivering 1000 volts, 600 watts for plate and 12 volts, 300 watts for filament. The “ESCO” Set is shown here furnishing Power Supply for 4—50 watters in a phone or telegraph set This is the Item used by CB8 in pioneer achievement of the first two way amateur wireless communication between North and South America. ELECTRIC SPECIALTY COMPANY Mark “ESCO” Trade 522 South Street Stamford, Conn., U.S. A. Manufacturers of Motors, Generators, Motor-Generators Dynamotors and Rotary Converters, for Radio and Other Purposes Say You Saw It In QST—It Identifies You and Helps QST

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LD i . » 4 A ee eee eee. A Resistor Known by the Company It Keeps he companies listed below = | “4 se . k of Harfield Resistors: Str Tele Western Union Teleg’h Co. p Sonora PhonographCo.,Inc. Cr poration Conner-Crouse Corp. A me ner Co. Magnavox Corporation Fanst Co., Inc. Jordan-Carisch Company M ( Inc. Electrical Research Pa Laboratories Sp Samson Electric Co, I 1 few of the more prominent : ave turned to Harfield Re- sist ist year. e resistor you want nake upa sample for you Write to .DWICK, FIELD, INC. —_ === Fy FACT HAR-FIEL) SALES DEPT. 215 Em UL. ' 109 Fifth Ave. Newark ry WIRE-WOUND New York RESISTORS OO I I a A 3 DODGE RADIO SHORTKUT r Better Key Work Fixes S ‘ Hesitation, Cultivates Speed R ts Slow Hams raise speed Pre us Failures. qualify and ter code and pass in HIGH SPEED METHOD Speed Practice) n 35-40 per class. Five few evenings One of MORSE SHORTKUT oO Kills tendency to mixup 1 as desire RTS FROM USERS Mailed on request. Radio Morse $2.50 Money order 1 50 cents. Cc MAMARONECK, NEW YORK. BIGRADIO From the ‘‘Big, Friendly Radio House’’ NJEW 1928 Book offers finest, west well-known sets; parts, accessories at lowest WRITE FOR THIS CATALOG ! western RadioMfg Co. 124 West Lake St., Dept. 61 Chicago, Ill. ene Say You Saw It In QST Tasmanian Division of the Wireless Insti- tute of Australia under the able leadership of P. Oakley Fysh, oa7PF. Our congratulations and best wishes for a long and healthy existence go to this, our latest, Section. Here is a summary of what to do about the International Contest if you live outside the United States and Canada in order to get in on the fun and to be in line for win- ning a prize as the best contact station in vour locality for “ne”’s and “nu”s 1. This contest will last fourteen days (Feb. 6, 1928 0000 GCT to Feb. 20, 1928 0000 GCT). For complete details see pages 31, 32, and 33 of December QST—also page 51 of this issue. 2. During the tests work just as many “nu” and “ne” stations as possible. Each station worked will give you a short test message with a special long serial number which identifies the participant sending the message. When properly acknowledged at the time and turned in to International Contest Headquarters as provided in the Rules of the Contest this counts one in your score. 3. To each message you get write a re- ply whose text and signature together con- tains ten or more words. Give each mes- sage the serial number of the message to which it is a reply. At the first opportun- ity give the reply message to a different U. S. or Canadian station than the one from which you got that serial number. When you have complied with all the Rules of the Contest this counts three in your score. 4. Work as many stations as you can to run up ascore. You can QSO many sta- tions during the contest—and probably add four points to your score for each sta- tion worked after the first one. Turn in confirmations promptly at the close of the contest (Rule 7). The U. S. wavebands that may be used are: 18.7-21.4; 37.5-42.8; 75.0-85.7; 150- 200. Canadian amateurs use the same waves and may also be found on 652.5 meters for work with British Dominions. The U. S. gang now uses 20-meters regu- larly and foreign amateurs who can use 23 meters will find it to their profit to do so in these tests to make 100% use of the 24-hours in each day. 80-meters is again becoming more popular for interna- tional work in some quarters and oppor- tunities here should not be overlooked. You should use any wave permitted by your government’s regulations, choosing the ones that are going to prove most effec- tive for your purpose. Take care that the stations you work are inside one of the bands mentioned above. Better mark the limits of the band on your receiver and keep the wavemeter around. North Ameri- can stations working outside their assigned wavebands will disqualify both themselves and stations they handle test messages with. Better get your station ready for the tests right NOW— in readiness to go after your share of the prizes. The prizes are It Identifies You and Helps QST rere _—" Pol

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The New AmerTran Push-Pull Power Amplifier S A new completely assembled two-stage unit con- taining a first stage AmerTran DeLuxe followed by AmerTran Input and Output transformers for power tubes. When operated from a power source supplying sufficient voltage, (such as the AmerTran A B C Hi-Power Box) the Input to the speaker is almost perfect, and fidelity of reproduction is limited only by the ability of the speaker. The energy out- put to the speaker is increased, especially at the lower musical frequencies. This means greater clarity of tone at low or high volume. The amplifier is easily connected to the detector of any good receiver, re- placing its audio amplifier. Fidelity of Reproduction The AmerTran Push-Pull amplifier is built in several types, depending on the type of power tubes A New Standard of Quality in preferred. Type 2 A P-10 is designed for 210 tubes Audio Amplification. and Type 2 A P-71 for 171 Tubes. The difference is : Connects to the Detector of only in the Push-Pull Output transformers. This Any Good Receiver complete unit is licensed under patents owned or controlled by the Radio Corporation of America. ° American Transformer Co. See this new unit and a demonstration of it at 178 Emmet St Newark, N. J . ° . e . . stores displaying the sign “Authorized AmerTran . Dealer”. Price $60 without tubes, East of the Rockies. “Transformer Builders for Over 26 Years” Guaranteed output—185 5 cash with order, volts at 55 f. o. b. Peoria, mils on > Illinois. Com- : 110V., 60 | plete with B. H. le Will Raytheon 125 —s KE m.tube. Money ane set with 1 to 12 tubes. back guarantee q with every unit. d (Formerly $35. ) . | Warren Electric Company, Dept. Q., Peoria, Illinois Say You Saw It In QST—It Identifies You and Helps QST 83

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at acc VOLTMETER Made for hard service but always R 0 ohms per volt,—for Radio serv- ice-m and manufacturers. Precision d’Ar ment, 3%4 inch scale, hand-cali brated nping is very fine. Polished base. Ranges, O-100 0-500 volts $28.00 Wr t “Hoyt Meters for Radio.” BURTON-ROGERS CO. B MINATOR urate and sensitive. Sole Selling Agents | BOSTON, MASS. | PACENT DUO-LATERAL COILS nenters, as and carry e for info Pacent Electric ¢ Corp. ACENT Duo-Lat- eral Inductance Coils are specially de- for laboratories, engineers, ex- well as for special “Headquarters” for Duo-Lateral a complete line of all rd turn ratios. rmation and prices. 91 Seventh Ave., N.Y.City ey, THE BEST $1 ed EVER andy 's andy 9 andbook § am ave u ordered ur Copy, of and co kit What ’ > be 84 1928 catalog is jammed full of — na lly known radio parts, catalog he rt W. ave Section show- ing th itransmitting apprr- atus. V g catalog—and for our AO nacle cabinets, ete it's in our 1928 a cont t—bot write immediately. SHURE RADI )., 343 H Madison St., Chicago, Ill. TT, every one of them worth while apparatus that you would like to have in your sta- tion. Just think of it, a chance to win some valuable additional equipment and to have some good fun at the same time. You will be adding to the amateur radio prestige of your country as well as collecting a stack of new records for the shack and making some new friends. If you can’t receive on 20, 40, and 80 meters you may be handicapped in the tests. The transmitter should be able to QSY quickly from one band to another, too, if your administration permits you to use several bands and if you plan to make best use of all the operating time at your dis- posal. The tests open February six, so plan to do any rebuilding necessary NOW. Do your best in the February tests. Let’s have a report of each and every score for QST however large or small it may be. There will be more about the prizes in an early issue and as complete a report after the test results are in as possible giving credit to everyone. Luck and 73. Be ready for action at 0000 GCT February 6 and don’t forget to report promptly at the end of the tests. Calls Heard (Continued from page 53) ek-4dba ek-4jl em-smuk en-Oga ep-lae ep-3co fm-8vx fm-ocrb fo-a4l fm-a4x ne-leo ne-2cg¢ ne-2fo ne-5go ne-5go nj-2pz nm-9a oa-2bb oa-2re oa-2rt oa-2rx oa-2rw oa-3my oa-3wm oa-3xo oa-4an oa-5by oa-5dx Oa-7ew oOa-7cx oa-7hl oz-2ae oa-3ai sa-cb8 sa-db2 sa-fb5 sa-hd4 sb-lab sb-lak sb-lam_ sb-lap sb-lar sb-lat sb-1bk sb-lbr s-lib sb-2am sb-2ig sc-2af sc-2ab sj-lrd su-2ak. Heard on KOGR at San Juan, P. R., by nu5SR-5PG lacm lamu lank lbak lIbbo Icdp ick lenf 1Imv Ilp Ipf 1xl Ixv 2abe 2ag 2afr 2alp 2aa 2ayj 2azw 2bfq 2bir 2bm 2bp 2bv 2cjd 2co 2cnu 2cx! 2hv 2jb 2pr 2rg 2sg 2uo 3aib 3apq 3aso 3bei 3cv 3ds 3fa 3hv 3jg 3at 8xav 4abe 5ajy 5akk 5amf 5ao 5aov 5aow 5apm 5Sarg 5ary Ser 5j¢ 5k! 5ns 5pk Sre Srv Svf 6am 6ble 6bur 6cgr 6is Tem Terp 7lm Tya Sagi Sakv Salu S8aze 8bbge Sbek Sbrf Sbrz Scnt Scjl Sesz Sif Yaa Yar Yas 9ayl 9bjl 9cfd 9cfn Ycim Yemz Ycue Ydau 9dnm Ydku 9dr 9dte 9dwo Yehr 9ekw Yena Yenr Yezt 9x] na-9hb nm-9a ns-8doi nq-2jt nc-2bb nq-2fg¢ nm-laa. KUJX, 8.S. Liberty Bell, QSL, nu9DPX, 1795 Lincoln Ave., St. Paul, Minn. Between New Orleans and Genoa, Italy R. J. Cotton, Opr. (October 2 to October 26) Cape Hatteras to Azores Islands (20 meters) lry lsw 1sz lzz lame lawe 2fu 2jn 2agn 4qb 5zav Sve Sadg Sayu 8azo 9mh Yadg Ybaf Yeag ne-2al ne-4fv eb-4rs ef-8fd sb-laa sb-lak wnp (40 meters) lag ick ldi 1f] 1fs lgp lim lin lika lle 1lp 1kh Imy Irf lue lut lvs Ixv lyb labd lage laqi laqp lara lask latr lauk lawm lazd lazw Ibak Ibbc lbed 1bjj 1bke lbsd lbvb Ibv! Ickp lemf lepd 2ag 2bm 2bv 2ev 2fw 2iz 2ke 2k! 2md 2nm 2ns 2qs 2rs 2sb 2sz 2tm 2tr 2ub 2uo 2vm 2vt 2abp 2acd afv 2agb 2agn 2ags 2ahi 2ain 2aio 2ajb 2alu 2amt 2apd 2aqu 2arb 2asb 2ase 2atr 2aub 2aun 2avl 2avq 2awi 2ayi 2ayj 2bao 2baz 2bdf 2bdh 2beo 2bgh 2bme 2bnl 2edr 2cjo 2crb 2cuq 3ag 3au 3bk 3cc 3cf 3dj 3ep 3¢gi 3ld 3mb 3nj 3pr 3qi 3rb 3su 3vf 3abo 3afw 3afx 3ahl Say You Saw It In QST—It Identifies You and Helps QST

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TERS SERS Uren na ITROHM Transmitting Grid Leaks and Rheostats now cover the entire line of transmitting tube circuits. ‘The prices on these amateur products are reduced materially. ‘Your dealer should stock Vitrohm Transmitting Products. If you have difficulty in obtaining them, write us direct. fATALOGUE i MAX. TUBE iUMBER PRODUCT RESISTANCE DISSIPATION CURRENT RATING PRICE 507-2 Grid Leak* = 5000ohms = 44 watts = 90 ma. ‘100 watts $2.00 507-3 Grid Leak* 5000 ohms 200 watts 200 m.a. 1000 watts 2.80 507-4 ~~ Grid Leakt 50,000 ohms 200 watts 60 m.a. 1000 watts 6.50 507-5 Grid Leakt 20,000 ohms 200 watts 100 m.a. 1000 watts 4.25 507-51 Grid Leak* 10,000 ohms 200 watts =: 135 maa. 1000 watts . 4.00 507-66 Grid Leak** 15,000 ohms 200 watts 120 m.a. 1000 watts 6.00 507-63 Rheostatt* 50 ohms 50 watts 1 amp. 5.50 507-59 Rheostat*t 20 ohms 80 watts 2 amp. 5.50 507-83 Rheostat* tf 12.5 ohms 60 watts 2.2 amp. 5.50 *Center-tapped ** Steps at SM—10M—15M {DeForest P or R. C. A. 852 Tube for R. C. A. 852 or DeForest P Tube De Forest H Tube t* For Primary Control *t Filament and Primary Control Ward Leonard/fectric Company 37-41 South Street NH Mount Vernon, N. Y. HIGH VOLTAGE FILTER CONDENSERS Manufactured by Dubilier Condenser & Radio Corp. 134 mfd. 1000 volts rated D.C. Working Voltage Extra Special at $1.35 each 7 mfd. 600 voits. rated D.C. Working Voltage Extra Special at $3.50 each 3.9 mfd. 900 volts rated D. C. Working Voltage Extra Special at $2.70 each Manufactured by Stromberg-Carlison Tel. Mfg. Co. 3%4 mfd. 600 voits rated D.C. Working Voltage Extra Special at $1.75 each All of these High Quality Filter Condensers, are brand new, and guaranteed as rated. They are excellent for use in your Trans- mitter, Eliminator or Experimental Work. RADIO SCHOOL Send for Catalogue AMERICAN SALES CO. 21 WARREN ST., N. Y. MASSACHUSETTS RADIO and OO this famous “ors CQ 18 Boylston St. Boston, Mass. -abinet — ~S QUARTZ CRYSTALS "recesses icz,Mesinum E —— = | prada One inch sections ground to within 1% of your specified ai . frequency ‘, 1 aes : . TS-108 MetetS cccccccccescosccocecece $17.50 OB-308 MECISTS cccccccccccccccccccccece 0.00 3 . : rs ers 15.00 THE BLUE RIDGE catalog ad Tull information. if Quotations on request for sections of any practicable 7x18x10'' Mahogany or Walnut Finish hour service, factor to you. MPecifications Thorough satisfaction guaranteed. Imme- di Delivery lo ( oinc. dohn T. Rooney, Consulting Chemist, 31 Calumet Bidg., Buffalo, W. ¥ ern 7 . “Ten years of Crystallographic experience’’ turers Hickory N Cc. Say You Saw It In QST—It Identifies You and Helps QST

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new CHI- RAD Short Wave Coils »0—40—80 Meter Band -Rad engineers to meet the de- mely efficient short wave coil. nting, hardware and _ three coils to cover 20, 40 and These coils are noteworthy in design, neatness in ap- liness in construction. All ntact. e Coils Complete for 20, 40 MG ccccccescecsececese $10.00 Oss Bend cs cecccdscece $ 4.00 i'ders—write for further go Radio Apparatus Co. 415 learborn St. Chicago, Ill. FLECHTHEIM SUPERIOR CONDENSERS FLECHTHEIM condensers are lable in every way. We recom- the amateur and the experi- ECIAL PRICES FOR QST READERS iy. éheceeanda $2.45 net > 6666006008 4.40 net SO eS 7.50 net W the remaining entire line of FI ( ONDE NSERS to the amateur ‘ 35 nation write for our folder. RADIO SALES COMPANY NEW YORK CITY ad rREET \. HERCULES | AERIAL MAST p. We pay the freight. All steelconstruction. 20 to ft. high. Roof or earth type complete with guy wires,mastheadpul- j ley etc. Write for full | Uf i Soe details. $.W.HullCo. Dept.6 J] Didone st 2048 E 79th St., Cleveland, Ohio # RADIO THEORY AND OPERATING P 790 Illustrations—Price $3.50 Mary Texanna Loomis ege; Member Institute of © ineers ‘ hook Te i by Dept. of Commerce, lly all Radio Schools throughout Colleges and High Schools. t Postage paid. omis PUBLISHING CO Dept. 7 t Washington, D. C. rder dire 86 Saib 3ajh 3ajx 3aks 3ali 3amm 3amx S3any 3bms 8bnf S8bwt 3cab 3cdg 3cdu 3ckl 4bu 4ch 4ei 4fi 4hh 4kw 4kz 4If 411 4lp 4mi 4ob 4oh 4on 4pa 4pd dpe 4pj 4qz 4rq 4tu 4uo 4vh 4wa 4xe 4daba 4dacn dact 4acv 4acy bas 5eb 5jd 50a Sry 5Ssw 5uk Byh Sbadz 5ahx Sair Sarg Sats 5awq Sayl 5zav bam Gece 6e¢g 6ju 6qi 6aak Gham 6bhr 6bjl 6biv G6bhwu Gcin 6ess 6dlj 6dlw 6dpu S8ce 8cj 8es Sex Sit 8jj Sli Slt Smp 8pl 8rh 8sf 8sx Svd S8vx 8zi Saff Sei Sair Sajt Saku 8ahx Salu 8anc Sapy S8axh Saxz Saye Sbbe S8ben 8bhz S8bja S8bjb S8bjx Sbou S8bpd S8bre 8bwa S&bwz Sbyh S8cae S8cau Scem Sedt S8chz 8civ Scke Sela Secmo 8enh Scent S8cpe S8cepf 8cpy S8csu Sewt S8evd Sexd Sexi 8daq 8dec S8ddk 8dkl 8dmz Sdod &dtp 9%ek 9hm 91d 91f 9mn 9rf Yabm Yabu Saeg Yaez Yamo Yaxh Yaxz avg 9bad 9bam Y9baz Sbbm Ybcb Ybeo Ybiw Ybiy 9blk 9bmm Y9bpw Ybyv Yccv Yeej Yefd Yciv Yckv 9 mz 9erd Yerj Yest Yevn Ydbi Y9dhj 9dck 9dmj Ydpj 9day 9dro Yecs Yecx Yemj Yenp ne-lbr ne-2be ne-3bk ne-5ef nm-xc6l nn-lnic nq-7cx sb-6qa sv-lxe. Azore Islands to Gibraltar (20 meters) lag lgp Imv lvz Iixv laff lahv laqp laur lavs lazd lbat lbbe lIbbo 1bkl lbqz lbvb lbwz Icio Icjh lenz Ictp 2ag 2ev 2fx 2ie 2kx 2me 2nh 2nm 2ow 2sz 2tr 2ty 2vm 2abe 2abp 2act 2agb 2aib 2aih 2aja 2alp 2amj 2aqu 2avq 2avr 2awk 2ayj 2bdh 2crb 2cx! 3cm 8ku 3nr 3py 3qm 3afx 3ajx 3amx 3avl 3car 3ckl 4ei 4fu 4jw 4lk 4ob 4qb 4te 4to duo 5qj 5yb 5acl Sayl 5zav Shb Ske Smp &Spl 8sf Suy S8ahk Sajt Salu &bek 8bhl 8bjb S8bwv Sbwz Sbzv Sces Senh Sesu Sexd Sded 8dml 8dmm S8dod 9mn 9xi Yarn Sbaf Scjw Yerj 9des 9dws Yecx Yemj ef8cp enOja ewH4 nelbi nelbr ne2be nq2ac. Gibraltar to Genoa, Italy (20 meters) lsz lajm lawe lbux 2aol 3hi 3qe. (40 meters) Imy lben lbsd lbvl Ichg 2je 2md 2rs 2vm 2afv 2beo 2cbl 3dh Spf 3ud 4eu 4ge 4by doe 4pk 4we 5aj 8agq 8cke Ben B. Skeete, 348 Halsey Street, Brooklyn, N. Y., aboard S.S. Samuel Q. Brown in port at Amuay, Venezuela (20 meters) nu. Ime izz 1sz lic lbbm 2va 2fn 2acy 2aol 2alu 4dv 8ve Yeap 9crd 9adg oz-4am. (40 meters) nu. l1kk llu liga 1zz lve ladw lbat laun 2uo 2vm 2alu 2atx 2cvj 2amj 2aun 3ag 3bnf 3bvz 3acm 3bms Saih 3pf 3ld 3ec 3cf 3bwt 4si 4nl 4acy 5aj Sre Suk 4aua Bair 5kge 5afn 5vx 5as Gahn 6biv 6dkx 6bjx 6beww 6cesx G6bia 6dz Gham 6bjh 6agr 6ahz Sec Scml &chz Scpf Secs 8It Scke 8dpo Sauq Salu Scoj 9dfj 9cel Sbea Suy 9uz 9crd 9bfj Yamo Yave Yaxz Yecv Yxi Ybaz 9bad 9hi Yei nce-2bq ne-3dq nq-5by ef8LC, Joseph Scalabre, 37 rue des Carliers, Tourcoing (Nord), France (20 meters) 1lxo Ixi Ixu 2ag 2aj 20e 2cx 2ahi 2acb 2afx 2ayj 8cdg 4qz 4oo 4vr daar 50a Scxd Srh Sek S8vd 9aqj 9efo ne-8re fo-aa9 fm-S8vx es-ea ep-lbl ep-lbk ep-lak ep-lag ed-7zg ed-7ne ed-7fp ed-7nb eu-O8 eu-Olra eu-O9ra eu-O8ra eu-l5ra ew-aa ew-h4 et-pom et-2xq ej-7qq ee-ear42 ee-ear73 ea-fk ea-rt] ea-cr en-Orz en-Odj en-Ole en-Oly em-smwg em-smtm em-smzy em-smxr em-smuf ek-4fn ek-4uz ek-4ff ek-4aeq ek-4hl ek-4xy ek-4ab ek-4ga ek-4uab ek-4df ek-4fv ek-4wx ek-4lb ek-4ur ek-4dbs ek-4kb ek-4ua ek-4vk ek-4vl ek-4aar ek-4hf ek-4dka ek-4vj ei-lfa ei-lau ei-lbd_ ei-ler ei-lIxw ei-lcu ei-lfe ei-lza ei-lea ei-lub ei-ldr ei-ler eg-2cs eg-6ik eg-6wo eg-6Ghi eg-6wa _ eg-5sc eg-llb eb-4cc eb-v8 eb-4ma eb-4zza eb-4hp eb-4tm eb-d4td eb-4ro eb-4lp eb-4dg eb-4as_ eb-4bf eb-4be ef-Sbha ef-Say ef-S8zyd ef-Sez ef-8flm ef-Smop ef-8fd ef-8f bef-8kl ef-Sfz ef-Sku ef-Spme « f-Sse ef-Sscaf ef-8rjr ef-Szar ef-Sctn ef-Sac ef-Sbtr ef-Srvr ef-Sfra ef-Ser ef-Sbup ef-Szed ef-8fbm ef-8ih ef-8zi ef-8ho ef-Sbri ef-Sez ef-Ssis ef-Skd ef-Ssst ef-Sei ef-8blr ef-Stdo ef-8tgs ef-Smmp ef-Sjz ef-Sad ef-8nno ef-Sdot ef-8ll ef-8zs ef-Sjicb ef-S8edb ef-8gc. efRO91, C. Conte, 24 Allee du Rocher, Clichy-Sous- Bois (Seine et Oise), France labd lahs lahv lajm lamd lani lanz laqp laat lasu lavj lazd laae lage lar lasi lbed Ibhm Ibke lbqs 1lbsd Ibad 1lbux lbv!l lbwm lbat Ibca lbhs 1bkp lbqs lcaa Ick lcmp licmx lcd icmf ldm lgp lka Say You Saw It In QST—It Identifies You and Helps QST eb-4dd_ eb-4di°

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ayj aq) lak xq dj oxr ixy -Alb aar -ler 1b -4td -4di mop srvr -8zi f-Sel snno ous- ibkp Ane) 8 y.\ 8 3 PRICES Kenotron Rectifying Tubes (Type T. B. 1.) MFD. BY GENERAL ELEC. Co These rectifying tubes operate on a filament voltage from 8 to 10 Volts and draw 1% amps. They will safely stand an A.C. input voltage up to 750 Volts and pass plenty of current and voltage for the My Big 1928 Radio Book conteine lat- est developments in short wave trans- mitting and receiving cates. > markable advance a. Eve srything for ‘“Hams’’ sale prices. Valuable information. Get FRE E ~— AMERICAN AUTO & Rane & mare. 6S HARRY SCHWARTZBERG, Bept 189 American Radio Bidg., ‘Monsees City, Mo. f. Laboratory plate of the Transmitting Tubes. They are also very efficie nt rectifiers for use in “ Battery Eliminators. STANDARD BASE NEW IN ORIGINAL CARTONS PRICE ONLY $1.25 Ea. AMERICAN SALES COMPANY.,21 Warren St.,N.Y.C. for Distortiontless ap eer 12,000. 48,000, 50,000, 100,000 Ohms, List $1.60 each, Special Sizes to Order, $2.50 each. Deal- ers write for discounts. When Better Resistances are made they will be Cresceats. Cresradio Corp., 166-32 Jamaica Ave., Jamaica, N. Y. A. R. R. L. Members -- What about your friends ? You must have a friend or two who ought to be members of our A.R.R.L., but aren’t. Will you give us their names, so that we may write to them and tell them about the League and bring them in with the rest of us? The A.R.R.L. needs every eligible radio enthusiast within its ranks, and you will be doing your part to help bring this about by recommending some friends to us. Many thanks, epOGvtechGasesbeenidakeehanenl 1928 American Radio Relay League, Hartford, Conn. I wish to propose DL. kiana eet eea Rete aeeameide OF idictenccdéacans0n0d$edunensesaananee DS scgnensteewntsndsgadebioksmecnanee ne FF (ideticntaineith he erkebkah ona dimmed Street & No. Place State for membership in the A.R.R.L. I believe they would make good members. Please tell them the story. TREC ee eee ee eee eee eee eee eee eee eee eee eee [ Say You Saw It In QST—It Identifies You and Helps QST

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Send the EASY Way With The Improved Martin ‘ce VIBROPLEX igh tor Continental or Morse Code Any speed from 10 words per minute-up Japannes Nickel-} | easy to operate. Simply press y enten does the rest. Adjustable r words per minute up. Saves ramp and improves sending 50 00 users. No station com- p-to-date BUG. Special Radio Model Extra Heavy, Specially Con- nts to break high current Sent anywhere on receipt of or registered mail. oe old Vibroplex. 25 Improved Martin Cenuine Vitcenten Nameplate is Order NOW! THE VIBROPLEX CO., Inc. 825B NEW YORK “VIBROPLEX” New York RADIO OPERATORS WANTED A. R. R. L. D ning Classes Start Every Monday. PECIAL CODE CLASSES for Illustrated Prospectus EASTERN RADIO INSTITUTE 899 BOYLSTON STREET BOSTON, MASS. THE 1 RADIO INSTITUTE can train you quick roughly because: M N AND EFFICIENT METHODS THO! H INSTRUCTION under staff of LIC! D COMMERCIAL OPERATORS MODER ARATUS including SHORT WAVE TRANSMITTER EN years a RADIO SCHOOL THE I lr, LARGEST and MOST SUCCESSFUL school England. RECOMMENDED BY THE ey THE BEST $1 YoU EVER SPENT! am-— ave ul ordered ur copy of andy’s andy kK? ERICAN RADIO RELAY LEAGUE an | An\c , OOK 5 im PARK ST, HARTFORD, CONN. 4 SE LF STARTER action as your filaments puts a sharp cutting peak perfect regulation, unlimited ed, full wave, no fussing or Now you know you want a M liagrams and data will convince solved ' ER ENGINEERING SERVICE, Rad ‘837 Rockwood Road, Cleveland, Ohio. oO * 3) lkh lmo Imp Imv Ino Ipo liad Iq! lIqv Irf itd lve lvyw lww lixv lyb 2abp 2abt 2adl 2afb 2agw 2ayb 2aor 2apd 2api 2asa 2atq 2avr 2axp 2ayj 2awn 2az 2abe 2ach 2afv 2agb 2ahg 2amh 2amt 2ate 2aun 2awk 2ayj 2bbn 2bdd 2bad 2bbe 2bce 2bgv 2bm 2buy 2cua 2cur 2cyd 2cerb 2cyx 2cwm 2cx 2cuq 2cx!] 2ev 2gx 2hr 2iz 2ie 2kg 2kr 2nm 2qh 2mb 2qc 2qs 2qu 2rs 2sz 2tp 2tr 2ty 2ub 2vd 2vm 3acu 3aef 3afu 3afv 3ajd 3aks Sali 3auv 3afl 2aib 3alq 3amx 3aqs 3bms 3bqz 8bwt 3cch 3ckj 3bnf 3cab 3cx 3dw 3jw 3lq 3qm 3wj 8mb 30q 3pf 3pr 3qe 3qm 3qp 3sz 4aba 4af 4am 4ap 4cy 4ei 4gy 4fi 4hz 4jd 4jz 4ll 4lk 4lu 4nf 4nq 4oc 4on 4rb 4rq 4rr 4se 4so 4tk 4dacv 4dacy 4ei 4fu 4ge 4oh 400 4rz 4rn 4tk 5av 5ayl 5eb 5yb Sabw S8adg Sagi Sajt Saub Savk 8axa 8bjx S8bqi 8bth Sben 8bjb 8bqm 8cau 8cei 8ccs S8cer Schp Scjw 8cxd Scxi 8cem S8deb 8ded S8dkx Sdsy 8es 8eq Shx Sjr Ske 8lt 8rt 8li Slt Spi 8rt Svd 8wk Yabu 9Yamo Yaxh Yamd Yapj Yarn 9bxi 9bjw Yeag Ycrj Ydte Ohi ne-lbh ne-2be ne-2ew ne-2fo nr-2la sv-lxe ne-Sae ne-8rg nm-1lj nq-2mk wya wuby wut aa7 kfzq. oz2BJ, Allan Evans, 269 Taranaki Street, Wellington, New Zealand (Heard during June, July, August and September) nu-lasf lvz lyb 2cty 3ahl 3bwt 411 4qb 5ja Sre Gaak 6ad 6ahl 6ahz 6ap 6aqd 6bb 6bd!l 6bfp 6bhz 6cag Gcuc 6cii 6esj 6eww 6cxi 6dch G6det 6deq 6dkx 6dlj 6dlr 6ec 6fh 6ew 6jn Gud 6xf 6xi Tacf Talk 7mk Tsf Tvq 7xf S8cau Scpq Scpu 9bht 9bnb 9bpm Yeet Yerj Idng 9dr 9kge 9ld na-7ep na-7kn ne-5gt nj-2pz oa-2ch oa-2dy oa-2he oa-2hh oa-2hm oa-2jw oa-2jy oa-2mh oa-2no oa-2rb oa-2re oa-2re oa-2ro oa-2rw oa-2rx oa-2rz oa-2wg oa-2xi oa-2yi oa-2yj oa-3am oa-3bd oa-3bq oa-3es oa-3hl oa-3jk oa-3le oa-3ls oa-3sr oa-3ut oa-8xo0 oa-4al oa-4bd oa-4eg oa-4cm oa-4go oa-4he oa-4nw oa-5ax oa-5be oa-5by oa-5he oa-5hw oa-5if oa-5yx oa-6sa oa-7ch oa-Tew oa-7dx oa-7zh oa-Thl oa-71j oa-7pf oz-lai oz-lax oz-lfe oz-lfq oz-2ab oz-2ac oz-2ae oz-2aj oz-2al oz-2an oz-2ay oz-2bg oz-2bp oz-2bu oz-2bx oz-2ga oz-2gg¢ o7z-2xa oz -2xd oz-3ai oz-d4aa oz-4ac oz-4ae oz-4am o7z-4az sb-2aj eb-4ww eb-4zz ef-8vv ef-8xo oh-6ajl oh-6akp oh- oul oh-6bdl oh-6buec oh-6exy oh-6dceu oh-6dlj oh-6dlr oh-6dpg oh-60a oh-6wu vim vis vit vlb vpd. 0z2GO, Harold G. Fownes, 110 Riddiford St., Wellington, N. Z. (Heard from Aug. 21 to Sept. 2) ibhs lia Imv 2ats 2cc 2xg¢ 3xq 4af 4du 4Il 4no 4on 4os 5aay 5agj 5amk 5axi 5g¢ 5lp 5lu 5ms 5ns 5rn 5zav Gabh 6agd Gahe 6akw 6alr 6als 6aod 6ap 6apd 6app 6auy 6bfp 6Gbhgev 6biu 6bmk 6bmy 6boe 6brd 6btaq 6bu 6bvt 6Gbvv 6chz 6enk 6cud G6cur 6ewk 6ew!l 6eww 6cezz 6dfp 6dice 6dkj 6dlj 6dpn 6dmh 6fu 6hkk 6ld 6rf 6uo 6ve 6zd Taa Tadd 7adj Takr 7bm 7ckf Tpv Sasm 8bp &8ddk 8g] Ske 9axo Q9axu 9azd Sbac Sbec Ybeq 9bld 9bmj 9bnd Ybul 9ces Bckk 9cks 9emq Ycok Yevp 9exe S9dha 9dpi 9dpl 9dpq 9dan 9dr 9dud Ydyt 9dz! 9ku 911 9nf 9nr 9rd na-Tabe na-7dq nq-2le eb-4ww eb-4zz ef-Sct ef-Scep ef-Sei ef-Sku ef-Snn eg-2nm ei-lau sb-2id sb-lax sc-2bl su-3be oa-5ecm oa-5gm oa-5jh oa-5mb oa-5rj oa-5xe¢ oh-6dpg¢ oh-6bdl oh-6dlr 00-geo oo-voc op-lew cab jes jkzb kegg kzet na voq wax. oa5CM, Reg. M. Anthony, 3 High Street, Unley Park, South Australia laao lbr lbux Iiccz Icje lemp 2ecrb 2ezr 3lw 4du 4js 41k 4nq 4rm 4rn 4tk 5aak 5agr 5ahs 5ahx SBajr 5akn 5aqf 5atf 5ke 5mx 5ql Sre Suk Sut 6aix bam 6agr 6ap G6Gapp 6ata 6atu 6auk 6baww 6bfr 6bif 6bix 6bpm 6brd 6boy 6buy 6bvb 6bvy 6bxi 6byz 6edx 6eii 6clu 6emq 6cua 6dgy 6djl 6dju 6dor 6dph 6dpn 6rn Taat 7bd Tmh Saxa Saly Scpq &8f! Sau Yara 9bea 9cei 9ceks 9dng 9efw 9ekf 9ekk 9eky 9dsh Ink Ypu ne-5ee nn-m3y aa-5ac ac-lcl ac-2ff ac-Shb ac-8rj ai-2kt ai-2kw aij-law aj-Isk aj-lsm aj-2by aj-4zz eb-4zz eb-4dac ef-8ix ef-8ln eg-20d gi-6mu gi-5nj fo-a%a fo-Isr oc-8xz 00-feo oo-bam op-lad op-lat op-lIbd op-lhr op-3ac oh-6bdl oh-6exy oh-6dki oh-6dpg oh-6dv oh-G6amu wuce jkzb samk. ed7ZG, H. T. Petersen, Norresundby, Denmark laao labd lapv laq lay! lbax tbsx Ibsd Ibv! lenx lemx Iemf Ickp lcpj 1di Ika 1kf Imo Imy Ipa Ixv 2ayj 2ang 2amj 2aew 2agn 2ag 2acb 2bad 2be 2cyx 2erb 2ef 2px 2sz 2tpr 2uge 2uo Bai 3bqz 3bq 3ck) 8cab 3gep She 3pf 3sh 3qe 4dei 4fu 41] 4rm 4rq 4tx Saxa Saly 8box Sbf 8bjb 8cxd. Say You Saw It In QST—It Identifies You and Helps QST |

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) : Seventh Edition Just Off the Press , 7 b i j Completely Revised and Up-to-Date , Of the 6th edition of this book reviewed by QST it was said this is perhaps > éé ° e 9? : The Best Radio Book That Ever Came To This Desk ; The standard Navy book on radio originally prepared in 1907 by Lieutenant (last year Admiral and ‘ C-in-C of U. S. Fleet) S. S. Robison. The 6th edition and the present edition revised by Commander S. C : Hooper, U. S. Navy, late Radio Officer, U. S. Fleet. d Price $5.50 postpaid (former edition sold for $8.00) 2 | S . . Address: Secretary-Treasurer, U. §. Navai institute, Annapolis, Md., U. S. A. k cé 33 Get the ADVANCE “Syne RECTIF IER 4 ‘NET this improved “Sync’’ Rectifier tarting Rec 7 no attentio yn—always " periority proven by its revailing ws in peody. With % HP. Westinghous motor, . international transmitting Lower in price in $55.00 complete. i] spite of higher quality Get the best. Write now for free descriptive h The Advance Sync Rectifier ~~ wil ~ folder reme 7) ea es duty nproves a ; eee titan center | tone ond bother ADVANCE ELECTRIC COMPANY : volume. Can be easily and quickly filtered 1260-1262 West Second St., Los Angeles, Calif. f 7 _ Saaen , EE - ; To Our Readers Who Are Not A. R. R. L. Members - Wouldn’t you like to become a member of the American Radio Relay League? We need you in this big organization of radio amateurs, the only amateur association that does things. From your reading of QST you have gained a knowledge of the nature of the League and what it does, and you have read its purposes as set forth on page 6 of every issue. We would like n to have you become a full-fledged member and add your strength to ours in ; the things we are undertaking for Amateur Radio, and incidentally you will 4 have the membership edition of QST delivered at your door each month. A ; convenient application form is printed below—clip it out and mail it today. re ere creer 1928 . American Radio Relay League, n Hartford, Conn., U. S. A. z Being genuinely interested in Amateur Radio, I hereby apply for membership in the American Radio Relay League, and enclose $2.50 ($3 in foreign countries) in pay- _ ment of one year’s dues. This entitles me to receive QST for the same period. Please ~ Ty Tr I Te I on nck ncdececiascennscsetsnstanones issue. Mail . my Certificate of Membership and send QST to the following name and address. ii n Tt BF j= eee eee esses eee ee eee ee eesSeSSSSSSSSSSSSSSSSSSSSHSESSSESESHSSHSSSHSHSSHSSSSSHSSSSSHHSHHHHH ESS r : eek Cl, FE ES ok k.iwadcdcwccicd wines cnsedesscundwondeesuaces eeaeneeaeeeneant Iv Grade Operator’s license, if amy .........cccccccccccccccccccsccvecsccccccccesess Radio Clube of which: & WRGMRDGE 66 ccc ccc cccccccncccesccedecceccccscesscccsceces ~ Do you know a friend who is also interested in Amateur Radio, whose name you = might give us so we may send him a sample copy of QST?..... 26-64. - cee ceeeeeeeees Say You Saw It In QST—It Identifies You and Helps QST

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The (¢ Powel Cros! Montana. $110 Without Tubes ense by The Crosley Radio up of patents controlled by f America American Telephone General Electric Company, West- Manufacturing Company, etc., the ible through the use of the irrent tubes—-UX 226 and for their filaments and rent from the houselighting the new alternating current nd brings to the radio user I f ecare-free radio. This AC battery type BANDBOX which r supply units and storage bat- t ced of radio! Sold at all If you cannot locate one, write nd literature. ssley Radio Corporation Ir., Pres. Cincinnati, Ohio ( redo, ow Mexico and West, prices rhtly higher. CROSLEY RADHT© fz Pov NAT W.A.R maT IC r Transformers Power Units for Plate Supply Pamphlet Q-124 ONAL CO. INC. Malden, Mass. A It isa for butt mast. “That h —displa Th American Radio Don’t Forget at the A.R.R.L. Em- sm is the badge of sry real Amateur. ilable in various sizes nN, pin, auto or radio- um may recognize ham the A.R.R.L. Emblem.” Relay League, Hartford, Conn. 90 eg2ASL, 124 Eversleigh Rd., Battersea, London, Eng. labd labk labp laci lacm lage lagl lahx lakm lans laqi lar laqt larx las lasf lat! lazd lbat Ibbr lben lbed lbke lbhs lbms lbnh lIbqs Ibr lbs lean leew lcop Icdt lIcjf lemf Ifl 1lfq lga 1lx Ilmf lmoa Inx lpo lql lqv Iry lve Ixv 2abe 2abw 2adl 2adu 2aff 2afr 2afv 2agb 2agp 2agw 2agu 2ag 2aha 2ahb 2ahi 2alu 2ang 2ary 2ase a 2ate 2ats 2aun 2auq 2ayk 2ava 2awi 2awq 2ayj z 2bad 2bat 2bbe 2bes 2bch 2ber 2bez 2bfy 2bwr 2 2cejd 2ems 2cod 2cox 2cob 2erb 2cty 2cue Zeux 2eyx Zew 2czr 2de 2hr 2kg 2mb 2iz 2qh 2qi 2or 2oe 2sg 2sj 2tr 2uy 2vaq 2za S3acf 3aef 3aes 3aed 3afp 3ajh 3afu 3aih 3aiv Sali 3avw 3au 3bms 3bop 3bq 3bqj 3bqap 3baz 3bzz 3car 3cdl 3chg 3cbt 3cef 3cze 3ec 3fe Shh 3ib 3hu 3jm 3ke 3ku 3mw 3mv 3mb 3nj 3pr 3pa 30w 3qe 3qp 3vx 4acz dab daf 4cl dey deck 4du dit 4iz 4jd 4js 4jo 4jw 4doc 4doh 4dok 4pf dab 4qz 4rk 4drn 4drr 4tu 4um 4uo 4tb 4vo 5ahp 5ajk 5ayl 5cl 5d! 5di 5kk 5nl 50a 5al Sala Sre Srd Szav Satf Sut Suk 5ux 5wo 5wx 5ud 5axn 6ij 6dhj Saj Sajt Sald Saly Salu Samt Sarx Saya Saxa Sazh Saui Sbag &bbge Sbhz Sbjx Sbki 8bkm &bm &bnh &bat S8boz Scpa &bth &Sbwz &byn S&ceo Sced Scfr Schu Scjb Scjv &clt Scnj Sepe Sepq erp 8dee Sdce 8dem Sddk 8dde &dgl Sdgf Sdld 8dme S8dmz Sdyg Sema Shwz &ke &pl Swk Svx Syt &zz Yacu 9Yabu 9aio Yaiw Yaid Yajd Yarn Yamo Yak Yavb Yaxz Yaxu 9bab 9bcg 9bex Sbfy Ybjw Ybkx Ybnp Y8z Ycej Yejb 9en Yenc Ycpq Yemv Yerj Yerd Yeq Yeys Ydee Ydck 9akh 9dku 9dr 9dsl 9dud Yef Yefo Yefw Yeky 9hr 9mn 9lu 9sr 9bax Ycv Ink Yesr Ybed Ydyh Yblk Ygd 911 9ciw 9bre Yaok 9deg Yeph Yrp Ydih Yeyp. eg2BVG, R. S. Foskett, 48 Woodland Ter., Lond. SE7 lasf lbbo Icfo 2vw 2cjj 5ara Save Savk S8cmo ell. eg2HJ, K. E. B. Jay, 19 Elm Close, Amersham, Bucks, Engl-nd (20 meters) laal laba laep lait lakz lapv lawe lba lbhs lbux lbw lbyv lbzj lcmx If] lia Imf Ird Iry Isw Isz Ixi lIzad 2aep 2aes _— 2bev 2bg 2bec 2cbo 2fn 2¢p 2md 2tp 2vs 2xad 3adm 3ank 3akw 3cfe 3¢p 3lq 3nq 8rq 4dv drm Sara 5jr 5zav Sadg Sagi Saxa Sayu 8bub Scbi S8cmo Scug &djv Sdpo Ybaf Sbmaq Ybay 9bws 9che 9cu 9b Suy ne-lap ne-lar ne-lbr ne-2al ne-2bl ne-4dp ne-8wg np-4sa sb-law sb-lib wnp xen-ocp. (40 meters) Sahl 3apn 3auw 3bms 3bap 3bqz 3bwt 3cbhm 3cbt 8ceb 3chg 3ckj 3ckl 3cp 3hh 3jm 3jn 3ld 3lw 3mv 38ng 3pr 3sh 3ua 3ug 3vf 3wj 3wm 3xav 4ce 4fc 4fu 4ge 4jd 4jw 4km 4lk 4ll 4nl 4nq 4doc 4oh 4ok 400 4rm 4rn 4si 4uo 4vh 4ws 5ao 5av 5dl 5he 5ki 5zav 6du 9bmm 9bwo Ybxi 9bxv Ycjh Yen Yene Yep Yepd 9cepq Ycrb Y9crj Ydku dr 9Yde Yecx Yegh Yell Yep 9fs 9jk 9lz 9pm fi-lew fq-pm ne-lbr ne-2be ne-2bg ne-3uc nm-9a nn-lnic nq-2ac nq-7ex nr-2fg¢ oa-2cm oa-2fe oa2rb oa-2ro oa-2yi oa-3bq oa-3es oa-3ls oa-3wm oa-7bq oa-7ch oa-7cew oa-7gd oa-7hl oa-7lj oh-6buc oz-2ae oz-2at oz-2bg oz-2bp oz-3ae oz-3ap oz-3ar oz-3au oz-4aa oz-4ae sa-cb8 sb-lah sb-law sb-lem sb-lcg sb-2al sb-2as sb-2ba sc-2ah ss-2bn wnp arcx xei-lrp. R. A. Rowden, 12 Pennsylvania Rd., Exeter, England lach lag lanw lanz laoh lasu lawe lazd lbkp lbyx lcje lccz lIcmf lom lej lxv 2ad! 2afb 2afr 2amd 2amj 2aub 2axl 2ayj 2bbe 2ih 2kr 2or 2af 2tr 3afu 3afv Sahr 3alq 3ant 3bge¢ 3bes 3bms 3bwt 8caq 3cgf 3ckl 3cp 3ec 3hu 3lq 3mv 3nb 3qe 3wj 4aba 4acn 4ec 4hl 4hx 4js 4jw 4lk 4ll 4lp 4nq 4doc 4oh 4qb 4qy 4qi 4rm 4rq 4sh 4si 4th 4um 4ux 4dwe 4wh Baak 5acl 5adt 5adz 5Safk 5ahp 5ajk Sane 5aqf 5atf 5atp 5Savs baxp bce Sew 5he 5ke Ske Sly 5ms 5ms 5nq 5qj 5sh 5uk 5vx 5wo 5wu 5zav 6agr 6bxi Trl Sacz 8ago Sahc 8ako Saly 8apo Sauq Sav! Savp Saxa &bhz 8bsr 8cjv 8cro 8crp 8cug 8exd S8dem dia Sdoa &it Srh Szzce 9adk Yafa 9ajj Yaue Yavp Yavz Yaxb Yaxo 9axu 9bal 9baz 9bel 9beq 9bfy 9bmx YSbpd Ybay Ybsh 9buy 9bvh 9cfn Yemq Yemv Yerj Yev Yevn Yevy YIcya 9dah 9dka 9dr 9drs 9dud 9dws Ybew Yef Yefk Segh Seky 9jr 9b 91d 9iz Ypu Yra. 400, A. K. Edgerton, 18—40 Street South, St. Petersburg, Fla. ef-8ba ef-8cl ef-Seo ef-Skg¢ ef-Snn ei-ler en-oja ewh4 fq-ocdl] ne-8ae nhca nm-Ir nm&a nr-cto nr-2ea ns-38jg nu-7abb nu-7afq nu-7ail nu7ajh nu-7bm nu- Viz nu7sf nx-Seq oa-2rb oa-2tm oa-3ig oa-5bj oa-5da oa-5dx oa-5mb oa-5wp oa-7ew oa-7jk oz-lrj oz-2bp oz-2go sb-law sb-2ag sb-2ay su-2ak wnp. Say You Saw It In QST—It Identifies You and Helps QST