Radio and Television Today (Jan-Nov 1941)

. INDEX • TO ADVERTISERS Page AEROVOX CORP 38 AMPERITE CO 48 ANSLEY RADIO CORP 41 BITTER CONSTRUCTION CO.. A 46 BURGESS BATTERY CO 42 CLAROSTAT MFG. CO.. INC 40 CROSLEY CORP 8 DU MONT LABORATORIES. INC 29 ERWOOD SOUND EQUIPMENT CO 45 FARNSWORTH TELEV. & RADIO CORP 2. 3 GALVIN MANUFACTURING CORP Cover IV GENERAL ELECTRIC CO 6. 7 HOWARD RADIO CO 38 HYGRADE SYLVANIA CORP 33 KEN-RAD TUBE & LAMP CORP 47 P. R. MALLORY & CO.. INC Cover II NATIONAL UNION RADIO CORP 37 PERMO PRODUCTS CORP 43 PHILCO RADIO & TELEVISION CORP 21 PRECISION APPARATUS CO 39 RADIO CORPORATION OF AMERICA 31 RAYTHEON PRODUCTION CORP 5 RCA MFG. CO., INC .18, 19 RIDER, JOHN F 40 SONORA RADIO & TELEV. CORP Cover 111 SPARKS-WITHINGTON CO 4 STERLING MFG. CO 44 STROMBERG-CARLSON TELE. MFG. CO. .24, 25 SUPREME INSTRUMENTS CORP 47 THORDARSON ELEC. MFG. CO 44 TRIPLETT ELEC. INSTRUMENT CO 45 VACO PRODUCTS CO 46 WESTINGHOUSE ELECTRIC SUPPLY 1 WILCOX-GAY CORP 27 FM LOOKS UP While every precaution is taken to insure accuracy, we cannot guarantee against the possibility of an occasional change or omission in the preparation of this index. ( Continual from page 26) which has been evolved to date, is Id use tubes known as 'limiters' which prevenl the amplitude disturbances from having any appreciable effect on the detector and to use plenty of amplification of the high frequency current before the limiter to insure Its proper operation under all conditions. So important is the function of the limiter that the best sets today make use of double-limiting so as more effectually to prevent the passage of amplitude modulated noise into the detector tube. There is no satisfactory substitute in the process of limiting in broadcast receiver use at the present time. "Another result accomplished by taking out the effect of amplitude variation is the reduction of interference from other FM stations operating on the same channel. Our correctly designed receiver will reject the weaker of the two FM stations and reduce to the vanishing point that type of interstation interference so troublesome in certain sections of the broadcast band at night. Receivers which do not have the ability to reject the weaker of two signals will get into trouble later on, as more FM stations go on the air. THREE FACTORS "It is well known that real FM reception gives a quality of reproduction never before obtained in radio. This is principally because of three things. All FM transmitters are designed to send the full musical range from 30 to 15,000 cycles. They transmit this range with much less distortion than any amplitude modulation transmitter gives. The receiver, if properly designed, can eliminate the distortion introduced by the transmission path, by the effects of noise, and by the radio-frequency amplifying circuit in the receiver, and can therefore reproduce a broadcast signal exactly as applied to the transmitter. It is essential that amplitude changes due to these various causes be effectually wiped out. Even where the first two effects are not present, distortion in the radio-frequency circuit will almost invariably show up and the passage of time and aging change the tuning lineup of the amplifying circuit. Proper limiting is the answer to all these troubles." \fiftM2SEk Oi/eti 100,000 5UPnm£]eMI Could there be more convincing proof of SUPREME quality, accuracy, dependability and fair price than the fact that servicemen who know their test equipment have invested over #5,000,000.00 in over 100,000 SUPREME testers? MODEL 504-A TUBE AND SET TESTER Our experience has equipped us to put even more value in the second 100,000 SUPREME instruments than in the first. Write Dept. RT-6 for full information on 1942's TOP line of testing equipment. RLWHYS INLINE Take advantage of the dependable satisfaction that Ken-Rad Radio Tubes give your customers. • Ken-Rad Tube & Lamp Corporation Owensboro, Kentucky Export Dept.: 116 Broad St., New York U.S.A. Cable Address: Minthorne, New York One user says: "Reception on the broadcast band is much sharper and interference has been eliminated". DCPCnDRBLE KEI1-RRD*& J U LY , I 94 1 47