Radio today (Apr-Dec 1939)

Low-power controls * Low-power wire-wound controls and rheostats in ranges up to 10,000 ohms. Power dissipation is 2 watts. Available with or without switch in complete assortment of shaft variations, lj^ inches diameter x 9/16 inches depths of case. Catalog on request. International Resistance Co., 401 N. Broad St., Philadelphia, Pa.— Radio Today. Vibrator tester -k Push button instrument tests all standard 6-v. vibrators — fused against shorted vibrators. Uses approved 5,000 ohms load. Roll chart shows correct button settings. Model 1671. $41.67, dealer net. Other models available. Triplett Electrical Inst. Co., 194 Harmon Ave., Bluffton, Ohio.— Radio Today. Midget transformer •k Replacement power transformer for small receivers is rated to deliver 480 v. CT at 40 M.A., 5 v. at 2 amps., 6.3 v. CT at 2 amps. May be used in half-shell, vertical upright or horizontal upright positions. No. T-13R19. Thordarson Electric Mfg. Co., 500 W. Huron, Chicago. — Radio Today. DeWald Phonoscope •k Combined electric phonograph and wireless record player has provision for attaching microphone. Will play through set 50 feet away. Plays 10 and 12 inch records — selfstarting motor. Crystal pick-up, P.M. dynamic speaker. Pierce Airo, Inc., 440 Lafayette St., New York, N. Y. — Radio Today. Noise/ess auto aerials •k Complete line of telescopic auto aerials designed so as to be free from all mechanical (and electrical) noise. Cowl and hinge-rod types for all cars. Also available are automatic and manually-operated disappearing type cowl antennas. Colored insulators for side cowl antennas. J. F. D. Mfg. Co., 4111 Ft. Hamilton Pky., Brooklyn, N. Y.— Radio Today. Inexpensive transmitting condensers k Light-weight compact transmitting condensers with brass plates and rods. Buffed plates. Alsimag 196 insulation. Bud Radio, Inc., 5205 Cedar Ave., Cleveland, Ohio.— Radio Today. You're leaving yourself wide open for a haymaker if you don't get yourself into condition for the new developments in Radio. Successes in business and in the ring are not made the night of "the fight." It's the training that counts. Be sure YOU are "ready" for the radio maintenance business », a wireless record player-.n facta// of the 1940's by conditioning yourself in the basics of °sdll°'°" l» not only explani. the television, radio facsimile, the' cathode-ray tube, photo »heory by mean, of ample .l.u« electric cells, etc. You'll have to know as much about ,raf,ons d,afams and "J""' bu' these developments as you know about a superhet— OR 9,ves vou ,h1e p,a,c,,cal taf-to find the profitable part of your radio maintenance business r°u "" combme theory ond prao going to better trained men. ( J™: °ut '" ^ay-Place Your The radio business is not a "fixed" business — it is pro f ef ow' gressing. So if you want to "be in there fighting" you had "An Hour a Day With better get into training NOW! Read carefully the contents Rider" Books— 60c Bach of the books described here and order today! On AUTOMATIC VOLUME CONTROL The cathode-,ay tube as the prin °» i^S^rS AN° cipal (actor in television receiving ^ *',,«,«„ ~.o™„.. sets is but one or the application. On D-C JOL. AGE «££ with which you will soon be laced. Qn AUERN AT|NG CURRENTS The use of the Oscillograph in .n |N RAD|Q RECE|VERS dustry is increasing every day in the testing of vibration, strength, AND DON'T FORGET engine pressure, etc. These indus "You Need All Nine trial users need servicemen to main RIDER MANUALS lain their oscillographs. You must Stop tussling with baffling service be up-to-date on this vital subject. problems. You need and will Watch lor date of publication. eventually buy Volume IX. Why -^—^-^—^— wait| Get ji and start benefiting VOLUME I from this vast storehouse of essential THE CATHODE-RAY TUBE AT WORK cifcui, dala ,oday. by John F. Rider ... „ . r Volume Price Covering This book has established itself as a IX $1 0.00 1 938-39 standard work. It is the most com VIII 10.00 1937-38 plete and practical book ever VII 10.00 1936-37 written on the subject. If you want VI 7.50 ?'""'* to be ready for television you must ' " " 7'50 1933*34 have the facts contained in this |||... 750 1932-33 book. This is the only book on the u 1.50 1931-32 subject written especially lor serv I 7.50 1920-31 icemen. Get it today! 336 pages — Over 450 illustrations $2.50 NEW — Out in April I "SERVICING BY SIGNAL TRACING" by John F. Rider Use the system ol servicing which is fastest — most modern — the system you can apply to all receivers regardless of age, type or make — independent of the kind of circuit or lubes used — independent of every limiting lactor heretofore encountered. In this new book you learn what happens to the signal currents — the development of control voltages—and how all receivers are brought to a common servicing level. There is one thing which is common to every radio set — the signal. Read this book and you will be able to service the most complicated set with greater speed and less effort, for "Servicing by Signal Tracing" is based upon the most fundamental thing in any and all receivers, the signal. 300 pages $2.00 Coming Soon! VOLUME II THE CATHODE-RAY TUBE AT WORK by John F. Rider New applications of the cathoderay tube during the past five years require that the 1939 serviceman know more about its operation, its characteristics and its performance. THE OSCILLATOR AT WORK by John F. Rider Eliminate guess work — KNOW! This new book tells all about oscillators that you use as a signal source — those in a receiver JOHN F. RIDER, Publisher, PRIL, 1939 63