RADIO'S GREATEST MAGAZINE AC IO ! C RAFT co=pot atiri9 11 RELVISIONADIO I OVER 125 ILLUSTRATIONS 194 2 iqt your sQtv«Q .. i PRICES? No matter what happens to prices -here at Harrison our large scale purchasing and our tremendous stock enable us to continue to give you the lowest possible prices at all times. ¡t pays to buy from Harrison! DELIVERY? With production facilities already great- ly overtaxed, deliveries are falling be- hind more every day. But, we anticipated this "Back-order Era" and placed pro- tective orders many months ahead. hallicrafters Super Skyrider Right now we have more receivers, Model SX -28. "Tope" in performance. 15 than at any tubes, 2, r.f. stages, calibrated bandspread. parts, tubes, etc., on hand etc. Covers .55 to 42 mc. time in our busy sixteen year history! You get faster delivery* from Harrison! TRIAL? When you buy anything from Harrison it has to be entirely satisfactory or you don't keep it. Try out your next receiver for ten days without charge or obliga- tion by ordering it from us. You get 100% cooperation* from Harrison! TRADE -IN? hallicrafters Sky Buddy By fair dealing we have built up the Model S -19 -R. A six tuber that largest Reconditioned Receiver business offers good results for a a ready market moderate price. .545 to 44 in the world! We have me with continuous electrical hallicrafters Sky Champion for your old set, and that means we can bandspread. Model S -20 -R. Excellent value. Nine give you the very best trade -in allow- tubes, noise limiter. preselector stage, ance. (We also buy receivers, transmit- .545 to 44 mc, bandspread. etc. Socket ters, etc., for cash.) for battery or vibro-pack operation. You get the *best deal at Harrison.' TERMS? Certainly! Charge Account or Easy Pay- ment Plan. Buy your Receiver. trans- hallicrafters mitter, parts, etc., on our easier terms Super Defiant at lowest cost. Model SX -25. Has Your credit is good at Harrison! all the features of sets selling * for nearly twice as GUARANTEE? much ! hallicrafters Ever thing is "guaranteed," but your Sky Traveler best guarantee is the integrity of the person with whom you deal. Here at Model S -29. You Harrison we go far beyond the standard can take it with warranty in order to please you! you! Works on You get a square deal from Harrison! s e l f contained batteries or any * AC or DC line. order! Built -in telescoping I'll be looking for your antenna. 9 tubes, .542 73, to 30.6 mc. bandspread, internal speaker, bat- BILL HARRISON, W2AVA tery recharger. (Send for my latest list of New and Reeon- ditioned Receivers) trmlontillallnleastassoeso gt's HARRISON bot hallicrafters and SERVICE! 11 West Broadway, New York City HARRISON RADIO COMPANY Worth 2 -6276 Get Into RADIO Quick! RADIO TECHNICIANS in Demand More Needed Now Than Ever Before Learn At Home To Make $30 $40 $50 a Week offers you to make MAIL THE COUPON I Find out about the many opportunities Radio more money Quickly and to prepare yourself for a good -pay job after the War. Whether you're eligible for military service or exempt. you should get my 64 -page Book, "Rich Rewards in Radio." It's FREE. It tells about Radio's present and future opportunities and how I train beginners at home in spare time to be Radio Technicians and Operators; how I tench operating principles of Army, Navy, Civilian Defense Radio equipment. 5 Reasons Why You Should Learn Radio Now (1) The Radio Repair Business Is Booming. Because of the shortage of new sets, and increased interest in Radio programs, fixing Radios offers many extra new opportunities for Radio Technicians. (2) U. S. Government is calling for thousands of CIVILIAN Radio Technicians, Operators and is RADIO TECHNICIANS, OPERATORS hold paying well for their services. (3) Government Orders for Radio Equip- good jobs in the 882 Broadcasting Stations in ment, amounting to millions of dollars are creating opportunities for men the U. S. with average pay among the country's with Radio training to earn good pay, overtime. (4) Radio Is Ready to best paid industries. Aviation, Police, Commer- Expand After the War. Television, Frequency Modulation, Electronic cial, Marine, Government Radio, forging ahead Instruments and Controls will offer new opportunities in the future. even during the War, employ Radio Technicians (5) Extra Pay in Army, Navy, Too! Radio Training offers men and Operators. Soldiers, Sailors, Marines with likely to enter military service, soldiers, sailors, marines, many Radio training win extra rank, pay, are ready for opportunities to win extra rank, extra prestige, more interesting good jobs after their military service is over. I duty and earn up to 6 times a private's base pay. train you to be ready when Television opens jobs Why Many Radio Technicians in the future. Mail Coupon for complete details. Make $30, $40, $50 a Week is a rital Indust ry durü.g wartime, Radio Is one of the country's fastest -eross", peace tiene industries. It Radio Technicians trained Copvernmentl Radio REPAIRING, SERV- branch Ms Radio today; Aviation Commercial. Pollee. Marine. sets in spare time or full time: in Radio businesses of their ICING, home and auto Station: in Radio Factories; Mine Radio Radio fields of Radio are expanding fast during the war. Many more new branches of own. Many hark. will create new peace-time opportunities after Radio sets (there are (Television. Frei tuncy Maculation. etc.). held r r rrleice of Itadlo to ',Ito advantage of these tovseut and future now 50,197,000 in use) the war. N 1 -.n, n the otirvd gives good jobs to opportundl L Soon Learn to Make $5, $10 thousands, offers more Beginners a Week Extra in Spare Time opportunities now r, r before. In feet. many men I train time Radio Terbnid:Inv t Part or T... r.. it::,lin sets In their spare time I give you than ever. Loudspeak- regular pa -,t : prefer to hold their It.o As you pros resa wüh nr Cmnxe. I and show you . rc to ü ,.uly. er Systems are an- special training do jolis. Many men I train pay for their Courses, sham you how to do more and store money- mak.. i,., spend besides. by luit.. c,diu repair work while learning. other source of profit 1 have extra money to for Radio Technicians. Experience While Learning How I Give You Practical student you spend enroll I start ending you toy 6 Big Kits of Radio Parts. As my Many Radio Techni- Very s after you Radio Circuits. Complete Radio Sets. am all about half your time building Radio 'Dating Equipment. Experiments, cians operate their own spare time or full time Prequency Modulated Circuits. You conduct more than 100 Radio make Radio Transmlttere, broad Radio business, servicing, repairing, selling Radio more than 600 wadi measurements your Interest- working with re ltRadioh part half udyingtd nay lesson ntextsyholds sets. Get the facts. Mail the Coupon. makes learning Radio at home faseln acts R. Drarllral, Find Out How I Train You for Good Pay in Radio ItELOWI I'll send my big 61 -page book FREE. It tails about my Course: the MAIL THE COUPON of Radio today: Radian opportunities for the future: shores types of lobs In the different branches doing. earning. 100 men I trained so you can see what civilian and servlre men are letters from more than NOW MAIL TIIE COUPON its an envelope or pasted of a These Men and Hundreds More You owe it to yourself to get these farts penny postcard. J. E. SMITH, President Got Their Start This Way Dept. 2CX. National Radio Institute Washington, D. C. $200 a Month in Own Business For several years I have been in business for my- self making around $200 a month. Business has steadily increased. I have N.R.I. to thank for WY start in this field. -ARIDE J. FROEHNKR, sou W. Texas Ave.. Goose Crock. Texas. J. E. SMITH. President. Dept. 2CX National Radio Institute, Washington. D. C. 1 $5 to $10 Extra a Week in Spare Time A Mail me FREE, without obligation, your 64 -page book "Rich Rewards in Radio" which tells about Radio's I am engaged in spare time Radio work. I average now and for the future. (No salesman from $5 to $10 a week. I often wished that I had opportunities enrolled sooner because all this extra money sure will call. Write plainly./ does come in handy.- TIJEODORE K. DuBREE. Horsham, Penna. Name Age Operating Naval Radio Station i am now operating the Radio Range Station, one Address the new simultaneous types, here at the Naval Air Station. Glad to give N.R.I. its share of credit in the success I have had thus tar.- GRIFFIT// City State SECHLER, Radioman First Class, U. S. Navy (Address omitted for military reasons.) RADIO -CRAFT for MARCH, 1942 385 IN THEISSUE k'nr'or porn ting "FM" for Odd Uses for De- HUGO GERNSBACK Plane Jn¡ts e rear Editor-in-Chief Recorder , .. Hor^e Tub Simple me H. W. SECOR CARLOS FROWEIN "M o 9'` .1 Editor Voltmeter Ait9n /anagin Art Director FM F Simple ment "P.P.." Proper Choosing Contents MARCH, 1942 Issue Unit VOLUME XIII -- NUMBER 7 Mailbag 388 DEPARTMENTS, ETC. Editorial: Radio War Guards Hugo Gernsback 391 Mailbag 388 F. M. Operating Notes 430 RADIO SERVICE SHEETS What Radio Leaders Think About "FM" 392 DATA (See Servicing) 426 Latest Radio Frequency Modulation and Its Future Uses Apparatus 438 Major Edwin H.