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March25 CentsHUGO GERNSBACKEu,DI TORUnited .Suite.und CanadaMAKING ASNOW LOUDSPEAKERSee Page 526Making "The Beginner's 'Book -EndTheAOVERB Cof A.F. C.-3'-Howto Make a"Junior"Radio Debunked for the Beginner50,000 RADIO-NovelOscilloscope1-Tube SetMEN READ RADIO -CRAFT MONTHLYwww.americanradiohistory.com
In spite of the fact that the demand for Supreme instruments forced us toin spite of the fact thatdouble the size and capacity of our plant in 1935approximately one -half of the servicing instruments sold in 1936 were Supreme instruments . . we were entirely unprepared for the smash hitmade by our new 1937 line! The unprecedented demand for our new lineput us in the biggest production jam ever experienced in our history!Because of this tremendous flood of orders we have added still more spaceand hired new, but highly experienced, men from various parts of thecountry. With this new set -up, production is now keeping step with demand.To those servicemen who were forced to wait for delivery of our instruments,we wish to express our deepest appreciation for their patience and loyalty.Get this free bookletfrom uulL'p"Where should the adioserviceman locate hisplace of business ?"The Supreme Instruments Corporation has made a comprehensivenation -wide survey to find outwhere is the best place for a serviceman to locate his business. Yourparts jobber has a free copy foryouwhich he will gladly giveyou. Write or see him today!-IMMEDIATE DELIVERY FROM YOUR PARTS JOBBERYour parts jobber can now make immediate delivery. Go see him today.Look at the new Supreme designs and models. You'll marvel at theirbusiness -like beauty! Their space- saving compactness! Their downrightefficiency! You'll discover, too, that every model has been designed tomake servicing for you easier, quicker and more profitable!-BUY ON S. I. C. EASY TERMSAnd remember you can buy each and every Supreme instrument fromyour parts jobber, on the S. I. C. time payment plan on easy monti.ly termsyou'll never D, MISSISSIPPI, U. S. A.-YOUR CREDIT IS GOOD WITH SUPREME!www.americanradiohistory.com
RADIO -CRAFTforMARCH,1937513OPPORTUNITIESare manyfor the RadioTrained ManDon't be an untrained man. Let me show you how to get your startin Radiofast growing, live money - making industry.Prepare for jobs as Assembler, Inspector and Tester-Radio Sales orService and Installation Work-Broadcasting Station Operator-Wireless Operator on a Ship or Airplane, Talking Picture or Sound WorkHUNDREDS OF OPPORTUNITIES for a real future in Radio!-a12 Weeks of Shop TrainingPay Your Tuition After GraduationWe don't teach by book study. We train you on a great outlay of Radio. Television andSound equip ment-on scores of modern Radio Receivers, actual Broadcasting equipment, TelevisionTalking Picture and Sound Reproduction equipment, Code and Telegraph equipment, etc. apparatus,You don'tneed advanced education or previous experience. We give you -RIGHT HERE IN THE COYNESHOPS -the actual practice and experience you'll need for your start in this great field. And because wecut out all useless theory and only give that which is necessary you get a practical training in 12 weeks.Mail coupon for all facts about my school and training methods.and industry.TELEVISIONTALKING PICTUREStoas aTelevision is surecomecommercialWhether this year or later, it will offeropportunities to the man who is trained in Radio. Here at Coyne you learn Television principles,and work on actual Television equipment. Talking Picture and Public Address Systems offeropportunities to the Trained Radio Man. Here is a great new Radio field which is rapidly expanding. Prepare NOW for these wonderful opportunities! Learn Radio Sound Work atCOYNE on actual Talking Picture and Sound Reproduction equipment.ARRANGE TO FINANCEYOUR TUITIONMail the Coupon below and I'll tell you about my finance planwhich has enabled hundreds of others to get Coyne training withvery little money. On this plan you can get your training first,then take 18 months to complete your small monthly tuitionpayments starting 5 months after you begin training. Not ahome study course.Mail the coupon for all details of this "Pay Tuition after Graduation Plan."ELECTRIC REFRIGERATION -AIRCONDITIONING-DIESEL ENGINESTo make dour training more valuable, I include-at no extracost additional instruction in Electric Refrigeration. Air Conditioning and Diesel Engines, taught you by personal instructionand actual work ,real equipment.n,PRACTICAL WORKACTUAL, PRACTICAL WORK. You build and service radio sets.You get training on real Broadcasting equipment. You constructTelevision Receiving Sets and actually transmit your own Television images over our Television equipment. You work on realPros.RADIO DIVISIONMANY EARN WHILE LEARNINGi.Founded 1899Coyne Electrical School500 S. Paulina St., Dept. 37 -8H, Chicago,Ill.If you need part -time work to help payliving expenses while at school, tell usyour problems and we may be able tohelp you as we have hundreds of otherstudents. Then. after you graduate, our.1;-.L t6Free Employment Department will giveyou life -time employment service. EveryCoyne graduate also receives a LifeScholarship, with free technical and business service and privilege of review at anytime without additional tuition charge.Mail Coupon Today for All the FactsH. C. LEWIS,At COYNE in ChicagoH. C. LEWIS,Talking Picture and Sound equipment. You learn Wireless Operating on Actual Code Practice apparatus. We don't waste timeon useless theory. We give you the practical training you'll need foryour start in Radio-in 12 short weeks. If you desire code, thisrequires additional time for which there is no extra charge.PresidentRadio Division, Coyne Electrical SchoolPaulina St., Dept. 37-8H, Chicago, lu.Dear Mr. Lewis:-Send me your Big Free Radio Book, and alldetails of your tuition offer, including additional instruction inElectric Refrigeration. Air Conditioning and Diesel Trainingand your "Pay After Graduation" offer.SOO S.NameAddressCityPlease Say That ion Suu It inStateRADIO -CRAFTwww.americanradiohistory.com
dio@ffFONiN!SERVICE MAN. DEALER111111111111111111111111IIIIIII111111I I I I111111IIIIIIIIIIIII I-RADIOTRICIANIIIIIIII IIIIIIIII111111IIIIIIIII111111IIII11111111IIIIII IIII IIIIIIIIIII IIIIIIIIIIIIIIIii11C. P. MASONC. W. PALMERAssociate EditorTechnical EditorR. D. WASHBURNE, Managing Editorumium nmunnunnuumuu nimianami numnuuunnmuunu nmumnm1111ulCONTENTS -MAR., 1937, ISSUENumber 9Volume VIIIHugo Gernsback 517Editorial: The Radio Newcomer518The Radio Month in ReviewMy First Transatlantic Wireless SignalGuglielmo Marconi 520New Information About Antennas.R. D. Washburne 521Radio Debunked for the Beginner.Wilhelm E. ShrageHow to Make the Beginner's "Book -End 3"Raymond P. AdamsJ. H. GreenHow to Make a Snow LoudspeakerMarconi -E.M.I. High -Definition Television at Alexandria PalaceHow to Make a "Junior" OscilloscopeWilliam FillerRadioReviewInternationalAnalysis of Fidelity Controls in the 1937 "Super Pro"Eli MartinNovel I -Tube Set Uses "Body" Antenna!How to Make the RADIO -CRAFT 1937 TelevisionReceiver -Part IIIH. W. ParoHow to Equip a Sound TruckLoudspeaker Baffles and Cabinet ResonanceMcMurdo SilverC. P. MasonThe ABC of A.F.0Direct -Coupling in a 30 -W. Beam-Tube AmplifierlA. C. ShaneyPart IThe Capacity Meter as a Servicing AidO. J. Morelock, Jr.Information BureauInterference-Radio's "Old Man of the Sea"522Carter536How to Use V.-T. Voltmeters in Radio and P.A.Kendall CloughServicing -Part I537Frank L.11111111111111I II111111111111111II1111111IIIIIIII I I III1111111111111111I IIIIIIl1I11111lIVIII I IIII111111IIIIIIIII I11111IIIIII11111111111I I111111I VIII 111111111111I11111111111111111I1111111A 5 -Band II-TubeHUGO GERNSBACK, Editor -in -Chiefumnim uunininim11524526526527Rack -and -Panel ReceiverJ. T. McCabe-537Milton ReinerPitfalls of the Radio Service Beginner.R. B. LawtonThe Latest Radio EquipmentBusiness Man's A.C.-D.CMake "The Executive"N. H. LessemIISet-PartC.Radio ReA.C.-DThe Much -Abused Ballasts forSamuel RuttenbergceiversIs It Economy to Connect Cells in Parallel?.L. S. Fox539539540How to Make the RADIO -CRAFT Set AnalyzerPart IIMake This Pocket -Size Multi -Test Unit-A538542543543RADIO SERVICE DATA SHEETS:No. 192 -Philco Model 37 -604No. 193-American Bosch Model 640No. 194 -Delco Models R -3208 (table) and R3209(console); Wilcox -Gay Model A-17 (chassis Model5445455485463JQ6 and 3JM6)Operating NotesORSMA Members' Forum546550Technicians' Data Service528II I III III1111111III I II I529529534534535I II II II I II11111111111111111111I II11111111111I 111111111I II I I111111I11I1111111111111111111111111111III II I II III1111111111111111111FORTHCOMING ISSUESWILL TELL YOU-530532532533II-Howto make an up -to -date short -wave diathermy ma-chine!-Howto make the RADIO -CRAFT tube checker thattests all the tubes now on the market!-How to make a combined "color organ" and "colortuning" adapter for any superhet. receiver!-How to design your own short-wave coils by chart!-How to make a beginners' radio set that entails onlyabout one evening's work and only a small cash outlay!ASK YOUR NEWSDEALER, TODAY, TO ORDER YOURCOPY OF APRIL RADIO IIII1111IIIIIIIIIIII1111II1111n 11 u1111IIIIIII II II1111111111111111111III111111111uu 11 n m m 11 n n 11 m n 11 u u1111IIIIIIIIIIIIII III11I1111I111111I1I I1111lIIlII1I1111IIIIIIIIIII:PublishedPublication office: 29by Radcraft Publications, Inc.Worthington Street, Springfield, Mass. Editorial and AdvertisingOffices: 99 Hudson Street, New York City. Chicago AdvertisingOffice: L. F. McClure, 919 North Michigan Avenue, Chicago, III.Western Advertising Office: Loyd B. Chappell, 511 So. Alexandria St.,Los Angeles, Calif.RADIO -CRAFT is published monthly, on the first of the month preceding that of date; subscription price is 2.50 per year in U. S. and Can ada. (In foreign countries, 3.00 a year to cover additional postage.)Entered at the post office at Springfield as second -class matterunder the act of March 3, 1879.Foreign Agents:American News Agency, 9A Green St., LeicesterSquare, W. C. 2, England.Paris-Messageries Dawson, 4 Rue Faubourg, Poissonniers, France.Melbourne-McGill's Agency, 179 Elizabeth St., Australia.Dunnedin-lames Johnston, Ltd., New Zealand.Text and illustrations of this magazine are copyright and must not bereproduced without permission of the copyright owners.London- GorringésCopyright5141937.Radcraft Publications, Inc.
forRADIO -CRAFTMARCH,1937515(ILL, YOUREPRFF LESSON.SHO.fDA B/LL HOWMAKE//yFALWAYSI'LL TRY, MARY,l' LL TAKE IT'FOOLING WITH RADIOOUR 5ET WON'TWORK- WILLYOU FIXON\COULDD pA yHOME TONIGHTrRADIOCAN'T FIND OUTWHAT'S WRONGGUESS I'LL MAKE ATOOL OFI.HELLO,BILL- GOTHELLOA'TOUGH ONTO -FIXVE-LATELYAND WHERE DID YOUIVE BEEN STUDYING RADIO AT HOME, BILL,SAY- WHEREWITH THE NATIONAL RADIO INSTITUTE. YOU'DID YOU LEARNTHAT TEST? ITSOUGHT TO TAKE THEIR,000RSE. IVE GOTA GOOD RADIO JOB NOW. LETS MAKE ACIRCUIT DISTURBANCE TEST- STARTING WITHLEARNLET MEHELP VOL)MYSELFJOE- WHEREYOU BEEN/ANYTHINGABOuTRADIO7WITH MARYßrìA GOOD ONE.rTHE AUDIO OUTPUT STAGEAND TESTING EVERY STAGERIGHT BACK TO THEANTENNA. LISTEN FOR4THE CLICKS WHEN ITAP THE GRID LEADSHERES THE TROUBLE,BILL, IN THEI VE SEEN THEIR ADSBUT I NEVER THOUGHT ICOULD LEARN 'RADIO ATHOME --I'LL'FIRST I.F. AMPLIFICATION STAGE. ILEARNED THAT TEST EVEN BEFORESTARTED TAKING THE COURSE,BILL. ITS DESCRIBED IN ATREE LESSON WHICH THEICOUPON RIGHTAND THEN CAN MAKEREAL MONEY SERVICINGI'STATIONOR INSTALL ANDLOUD SPEAKER SYSTEMSr\youHAVE TRAINED MANY MEN TO STARTA SPARE TtME OR FULL TIMERADIO SERVICE BUSINESSWITHOUT CAPITALIM you W3Ilt to mate tr1'111 esure that I rtrait, ,home inRlrr Illo, ter it g,wwl Itad'wJolt that rú send)a molt. le .nI ah.onde's. FREE.ad R, see for rouraetf how eit is to.d,,r.taud Ih rI itu ohad loo terÍwirtl txP, r'rm ,train -tug.),I11amr,.Many Radio ExpertsMake 30. 50. 75 a WeekRadinhrtadcating stations outdo,' engInrer:, operator .SIatlon managers and tar UP tu 53.Ú.n aSpare time,aRadio set S.ry ill ng pass a, much a: sod( Ii, 3un aFull time Radio scrtieing hints July am,h as 5:111.'cs['week. Many Itadiu E prrl5.5vn and operate theiru full time or' Part tinte Radii/ sai,.alolbustmoo,. Racily manufacturers and jobbers rnR'.yrSfsP or:, foremen, engineers. servicemen. paying up toa year.Radio operators,"hips get good Dayand are the ro Id besides. Automobile. toile,. aviation.nnm.la!, Radio, and loud speaker .ydrm: offer oelolla,rnmilies nab'. ami for the Nntrt. Television pntml,,Malty gaol job,:n. Menhave trained arc holdingJul, . in all the,. wbram -hr, of Radio.,o'sMany Make 5.Extra InWhilePractically every,nd,b,I 15aJIruTOR A1.111A-010 Itrip',E.-\I,ILLULLTIME JOBdiii,BILL- I'M SOGLAD I ASKED YOUFIXTOOUR RADIO.IT GOT YOU STARTEDOHOUR WORRIES ARE OVER.IM MAKING GOOD MONEYNOW,THINKING ABOUTRADIO AS A CAREER,AND NOW YOU REAND THERE'SABIG FUTURE AHEADFoR uS IN-vRADIOGOING AHEADSO FAST1MAT!J. E. SMITH. PresidentNational Radio InstituteDept. 7CXWashington. D. C.MAIL THISPu. trap.INOWl.ammo oI elan tleo MOmoo mrao1J. R. SOIITII, President, Dept. 7l'XNational Radio Institute, Washington, D. C.1Dear Mr. Smith: Without obligation, send me a sample lessonandYour free book about the spare tinte and full time Radio opportunities,and how I can train for them at home in enure time.II(Please writeWeekTimeLearningneighborhood no IsÌad spare lime serviceman. Theas you enrollslag sending sou)Extra Money Job Sheets. They s inu how to do Radio Repair job:that you can rash In on Quickly.Throughout your trainingsend youplans and idea. that have made good'pare timeney f rom 2tot 50000 a year-foror hundreds of Eel lops. I send you special Radio equip.PR ETTY SOONBE READYGet My Lesson and 64-Page Book FREEail Coupon,III ad ¡t ismu, Sample 1.,. -.n. IPis',' Rot:. "Rich Iteuat. i!Sid,forep, any 'Him,'tPtoar, o:d. 31v 6.d.,.pare ime and full time omwrluniamllb,.e rsnirgTir'rrirn n m' leu: abolit my Training in Radinanddes ton ;n'í,11. ainuit tIloi,., Hack Agreement: slam.annal haler, t'roo,Ih:oe trained,whatilpr are doing d ro, ontiIi, Fim1 NO tract tellingMieSAW' nIl.t11. TilE OI l'US iii .n Iv:I ,. R:,dior na'R itit1FUN ANDI¡mN.R.I.ILL,,IT CERTAINLY ISEASY TO LEARN RADIO TICEWAY. t STARTED ONLYA FEW MONTHS ASO. AND "MALREADY MAKING GOOD MONEY.THANKS:KNOWTHE DAYBOUGHT If.ASTHIS SPARE TIMEWORK IS GREAT lI 10.\,.LummoxGOODSMITH. PresidentI,, 1l0ndmd ex Per norm: oldNational Radio InstitutehuiIiivit. whb'h illuIrate Itn: rl ant Itadiu principle;.11vII,,1practical Radio Leper ienee while le au:.,) nl/(/SERVICING TIPSFOR A GOOD RADIO JOB1\l*Apia. SOUNDS ASYES, I WILL SEND YOU MY LESSONSSOPLACES. AND THENATIONAL RADIOINSTITUTE HAS TRAINEDHUNDREDS OF MEN40R JOGS IN RADIOTRANSMITTING\1iTREETOA RADIOWITHRADIO SETONE OF THEIR ADSON RADIOAVIATION RADIO, POLICERADIO, TELEVI5ION,ELECTRONIC CONTROLS RADIO 15 SURELY GOINGJOBOR GET ABROADCASTING ORAWAY7s ."MAIL THEIRNATIONAL RADIO INSTITUTESENDS YOU WHENYOU MAIL. ACOUPON 'FROMJ, ¿M CONVINCED NOW THAT THISCOURSE 15 PRACTICAL ANDCOMPLETE. I'LL ENROLL NOWISpareplainly.(.I1Name .AgeAddress1CityPlease Say That You Saw It inStateRADIO -CRAFTIlxl1i
RADIO -CRAFT5169forMARCH,1937x 12INCHESYOUR JOBBEROR FAVORITEMAIL ORDER HOUSEHAS COPIES OF THE1936OFFICIAL RADIOSERVICE MANUALORDER YOUR COPY NOW-OR WRITE TOTHE PUBLISHERS DIRECTBigger and Better than Everdlamaterial andIftoesaleofieonsirlrrabl, spreviousaluvsir. c annuliternbaekMletIsJnoiauurany indirai ioneeriee Men will be using thisthen many thousands morevoluurrs.new 1tI 1' Manual than any of the VrrvIuusof sets manuf art tu'rotThe r w Manual i erates all availably diagramsNol out, di asram-.models.1037advancepint,raoAplusmanyduring 1035 andfrequencymediatepeak,, socket vultIntelbut err tiro Lda, alignment pivicedure,r ably diagrams etc., etc., are included. BIT OF INFORMATIONu antiIN THIS MANUAL! EVERYTHERE IS ENOAND NO USELESS MATERIAL. JUSTNO REHASHIS FRESH. VITAL.t.11S has born carefully edited and remTO GIVE "BULKTO THE BOOK. The entireMANUAL iselted to the best in: erests of Service Men. The 1936 OFFICIAL RADIO SERVICEan escellent and timely hnnlment.1ge.'r.1PARTIAL CONTENTS OF 1936 MANUALNew PracticalBinderNote.attheIttleft. the detailsof the new bind.er used on thismanual.o . but facilitates removal andreplacementofindividual orges.1,200PACES2,500ILLI'STItATIIINSLooselea( BinderHard CorersSchematic Diagrams; more than 1500 of them,covering practically all sets manufactured during 1935 and 1930, plus many advance 1937models. Many of them have the operating voltages of the various tube elements printed directly on thons.Wiring Diagrams; wherever they have been obtainable, the wiring diagrams of the mor. corn elex receivers, such as the all -wave and highfidelity sets, have been included.Miscellaneous Diagrams: these include speakr eunneetions, optional phonograph connecions. power transformer connections, It. F.and I. F. coil connections, complete phonograph motor connections on combination receivers. etc., etc. Wherever these diagramswere available they have been included in theService Data: wherever the information wasmade available to us, such data as typicalfaults in a given receiver, their symptomsand remedies. was included in the 1936 Manual.Assembly Diagrams; on combination models,i. e. sets combined with phonographs (eitherthe manual or automatic types(, complete assembly diagrams are given. These diagramsshow the relationship of the separate units toeach other and the way they are inter -connected.Operating Voltages; the operating voltagesgiven in this Manual (for more than S0'.á ofthe sets listed) are the normal voltages: anydeviation from these values indicates trouble inthe associated circuits.Trade Name Index: in the back of the book.is a complete index of trade names and theirrespective manufacturers.Complete Tube Chart; in the back of the Manual will be found the latest. and most complete tube chart of all type tubes ever manufactured for receivers.Large Cumulative Index: includes all setsprinted in the 1931, 1932, 1933, 1934, 1935 dumes as well as the present 1936 Manual. Thesets in this volume have been listed in the index in an entirely new and more convenientmanner so that the busy Service Man need nolonger thumb through an entire manufacturer'ssection in order to find some particular pieceof information. He need but consult the index.cannot supply You. order any of theManual.Intermediate Frequency Peaks; all set modelswith few exceptions have their respective intermediate frequency peaks marked either directly on their schematic diagrams or in theirnotes on alignment procedure.Alignment Procedure: even if space permitted.it would not have been advisable to print thelignment procedure on all the simpler setsi r one would have been a repetition of theother. On the more complex receivers, however,the all-wave and high -fidelity sets, completealignment procedures, step -by -step, have beenincluded.If your jobber or mail order houseOFFICIAL RADIO SERVICE MANUALS or the OFFICIAL. RADIOSERVICE IIA.VDIROOK front the publishers. Send your remittance in formof check or money order -or. if you send rash or unused U. S. PostageStamps. be sure to register your fetter. ALL. ORDERS ARE FILLEDPROMPTLY. BOOKS ARE SENT TO YOU POSTAGE PREPAID.Address Dept. RC-8.171936RADCRAFT PUBLICATIONS, INC., 99 Hudson St., New York. N.Y.GERNSBACK RADIO SERVICE MANUALS ARE AVAILABLE FROM JOBBERS AND MAIL ORDER HOUSESPlease Say That You Saw It inRADIO -CRAFT
adio @ff Ice THE-SERVICE MAN DEALERRADIOTRICIAN"Takes the Resistance out of Radio"Ai111111111111111111111111111111IIEditorial Offices:I II I I II I II I II I I II I II I I II I I II II I I II I I I I II I I II II I I II99II II111111111111 IHudson St., New York, N. Y.I III I III III I I I I I 11111111
ELECTRIC REFRIGERATION -AIR CONDITIONING -DIESEL ENGINES To make dour training more valuable, I include -at no extra cost additional instruction in Electric Refrigeration. Air Con- ditioning and Diesel Engines, taught you by personal instruction and actual work n, ,real equipment. P
