Blueprint Section Every Month In This Issue- JULY Ten Commandments for the Listener 1925 ,A New Super-Heterodyne Solving Tube Troubles 25~ News of Radio Age's Popularity Contest ',. ' TYOUR B ADCAST FAV S ER- \ ~ AUT~DYNE * * New! A Perfected Super-Heterodyne Again Silver-Marshall Engineering leads the field, just as it has since the first Silver Design was offered less than a year ago. Not content with a seven-tube super-heterodyne, which has become the acknowledged standard of comparison with radio engineers and editors, McMurdo Silver, Assoc., I. R. E., has developed "The Super-Autodyne," a six-tube receiver that will outperform average seven and eight-tube sets. Read the description of this remarkable radio achievement in this issue of "Radio Age." Plans and instructions describing this set in detail may be had for SOc. Complete Parts Each Each 2 S-M 30SA S ·L·W Condensers . .S 5.00 2 Thorriarson 3 1· 2·1 Transformers .. ............ $ 4.00 2 4 " Moulded Oials._ .............. 1.00 2 .002 Condensers. ................................... ....• .40 1 U . S. L. 6-0hm Rheostat. ...... .... 1.00 1 .0075 Condensers.... ..... ................. .... 75 1 U . S. L . 240 Ohm Potentiometer._ ....... 1.50 2 .000025 Balancing Condensers.................... I.SIi 3 Insulated Top Binding Posts ............ .05 1 S·M .2S Meg. Leak.. ................................ .50 1 Carter 101 Jack .... ... ............. .70 1 S· M 2 meg. Leak ........ _................................ .50 1 Carter 102A Jack.............. .... ........ .80 1 Ca rter No. 3 Jac-k Switch., ..................... __ 1.1S 1 S·M 211 Filter with Matc hed Timing 1 Benjamin 8630 Switch._............................... .30 Capacity.. .................................... .... 8.00 1 Belden Color cable ........... __ .... .85 2 S· M Charted Intermediate Transformers 8.00 1 Pair Benjamin 8629 Shelf Brackets. __ ... .70 1 S·M 101B Coupling Unit .. .................... 2.50 1 Bakelite panel, 7*x18*lt3 · 16 ". drilled. 1 S.M 6·Gang Socket shelf (S36· 201A, 537· grained and engraved.............................. 6.00 UV199). ............ _ .................. _ .................. 10.80 Spaghetti, bus bar. lugs, screws, buts, etc. 1.00 Send for "The WHY of the Super-Autodyne"-It's Free; *T rauc Dealers-Ask for Our New S-M Catalog l\ lark 114 S. Wabash Avenue, Silver-Harshall Chicago, Illinois T Tested alld rtppr()ved by RADIO AGE x.. RADIO AGEjor July, 1925 The Magazine oj the Ho ur Stations * Don't Bunch " Oil.tlzeDials --'-=====:::;'---P,~TENT PENDING Tllni1l9 Silllpl!fiecl Now / HE day of tedious fumhling ahout for your stations is past-science has heen T brought into play. Now, with the Ultra-LowLoss Condenser you can instantly tune in on any station as easy as turning the hands of a clock to the hour. \Vith one station of known wa\'e length located on the dial, all others can be found instantly. Each degree on a 100 degree dial represents approximately 30 meters difference in wave length. This applies to hoth high and low wave lengths. Other than 100 degree dials vary accordingly. This simplification of tuning is made possible by the new Cutless Stator Plates to be found only in the Ultra-LowLoss Condensers. Every feature of the Simplifies radio tuning. Pencll record Ultra-LowLoss Condenser was developed with one predominating purpose-to a station on the dIal-thereafter, sim­ overcome losses corrunon in other condensers. Designed hy R. E. Lacault, ply turn the finder to your pencil mark and you get that station inst3nt­ originator of the famous Ultradyoe Receivers and Ultra-Vernier Tuning Controls. ly. Easy--quick to mount. Eliminiltes At your dealer's. otherwise send purchase price and you will be supplied postpaid. fumbling, guessing. A single vernier control, gear ratio 20 to 1. Furnished Duign. of low/oss coifs I,,,"uited witit cach condenser lor amateur and broadcast U1av' clockwise or anti·c1ockwise in gold or lengtits showing which will f"nClioR mod efficiently witl. the condenser. silver finish. Silver $2,50 Gold $3.50 To Manufacturers Who Wish To Improve Their Sets Mr. Lacault will gladly consult with any manufacturer regarding the application of thi. condenser to his clrcuit for obtaining best possible efficiency. This seal on a radio product is CON DEN 5 E R • your assurance ~:d a~;~~it~~ PHENIX RADIO CORPORATION, 116-B East 25th St. of La~ult de· Ifi~~~~~~~~!!!!~~~~~!!~~~~~~~~~~~~~~~~!N~e~W~Y~O~r~k~C~i~ty~~~~~ ¥- T es ted and Approved by RADIO AGE ¥- 2 RADIO AGE for July, 1925 The Magazine of the Hour A Chat With the Editor OU can count on the fingers The Magazine of the Hour of your two hands the basic Eslabli.h.d March. 192Z Y radio receiver circuits from WITH WHICH IS COMBINED RADIO TOPICS which all the many scores of hook-ups now existing may be developed. All those basic circuits Volume 4 .; lilly, 1925 Number 7 I are to appear in blueprint form in the August issue of this magazine. Our technical staff has selected CONTENTS the typical circuits which represent the various bas;c arrangements, Cover Design by A. P . Ehlum most of which have appeared dur­ ing 1924 and 1925 in RADIO AGE. Page John B. Rathbun, the able Radio Editorials ............................................................ 4- draughtsman whose blueprints in this ma~azine have become stand­ Four, Five Or Six Tubes? ............................................. 7 ard in schools and in many thou­ By Roscoe Bundy sands of radio homes, will have Learning Tube Characteristics. ........................... _... __ .. ll in this de luxe edition of RADIO By H. Frank Hopkins AGE an exhibit of testeci basic How Much CouplingL ... __ ...................... _............ _... .... 13 circuits which will make our August By Brainard Foote issue one of the most important The Six-Tube Super-Autodyne.... ................... __......... 15 radio contributions since broad­ By McMurdo Silver casting began. The blueprint sec­ Vacuum Tubes as Distortion Deyices ............. _. __ ....... 18 tion of the August number will By Dr. Peter I. Wold itself be of almost the bulk of the A Word on the Care of Batteries. __ ............. _............. _. 19 regular magazine. With the addi­ tion of other standard RAD I 0 A Simplified Portable Super-Het.. ..... __. __ .................... 21 AGE features the book will take By A. j . Haynes on proportions that should delight Tricks of Summer Static_ .. _____....... _._ .. .. ................ __ .24 the fan who wants his radio course "Gloria Confesses": A Photogra ph .... _...... _.. .......... 25 from crystal to super, all under RADIO AGE " What the Broadcasters Are Doing" one cover. Studio-Land Feature Section. ____ ...... _.. .............. ___ 26 Notwithstanding the un.usual RADIO AGE Institute Monthly Tests._.... _. _........... 34 value offered in this big issue of our magazine the news-stand price will RADIO AGE Blueprint Section. .. _. .............. __ .... ........ 3S be the same as other issues; 25 By john B. Rathbun cents. It IS a matter of wide Pickups and Hookups by Our Readers ................. __ __A 3 conunent that RADIO AGE costs With the Radio iVIanufacturers. ____ ..... __.... _...... ... _... 69 no more from month to month than other standard radio publica­ tions, although its blueprint section in each issue ' sets it apart from all other magazines. Now Radio Age is published monthly by RADIO AGE, Inc. Member: Audit Bureau of Circulation •. we are to offer you a complete collection of blue prints with Address all communications to RADIO AGE. INC. complete constructional instruc­ Executive, Editorial and Advertising Offices tion in a single issue and for the 500 N . Dearborn Street, Chicago, Ill. regular price. Publication Office, Mount Morris, Ill. We would advise readers who FRE DERICK A. SMI TH, Editor wish to make sure of getting this FRANK D. PEARNE, Technical Editor remarkable August number that M. B. SMITH, Business i.{anager they tell their newsdealer to reserve their magazine for August NOW. A dvertising Director If your dealer does not handle HARRY A. ACKERBURG 500 N . Dea rborn S I. • Chicago. 111. RADIO AGE write to us at 500 North Dearborn street, Chicago, Eastern Representative enclosing 25 cents in stamps and DAVIDSON & HEVEY. 17 \Vest 42nd St., New York City we will mail you one on July 15, the day it goes on sale. Final Advertising forms close on the 20th of the 2nd month preceding date of issue Vol. 4. No. 7. h su.d monthly. Subsc ription prke $2.50 a year. July. 1925. Entered as s.cond-<:Iass matt.r a t post office at Mount Morris. J1Iinois. under the Act of March J. 1879. ~~, ~iqh' . I . ts. ""RA.DIO A G E./~ . Editor of RADIO AGE RADIO AGE for July, 1925 3 Get a good set­ and Evereadys (Eadcrn Standard T i me) For real radio eojoymeot tune in the "Ever­ ea.dy Group." Broadcast through stations-- To ENJOY radio for the rest of your life, get the WEAF New York WEAR Cleveland best set you can afford. There are receivers at all WJAR Providence WSAI Ciociooati prices, made by reputable manufacturers; it isn't WEEI Bostoo WWJ Detroit WFI Philadelphia wceo{ Minoeapolis necessary for anyone to get 'round-the-corner, un­ WGR Buffalo SI. l'aul proved, unreliable merchandise at any price. That WCAE Pittsburgh woe Davenport applies to batteries too. Eveready R adio Rattcries are made in so many sizes and prices that there is a correct, long-lasting J~veready for every receiver and for every radio home, ship or commercial sta­ tion. Specify Evereadys for· your new radio set. It is false economy to buy nondescript batteries at any time. In the long run you'll find it most economical to buy either the large or extra large Evereadys. Alwars buy Eve re ad ys and enjoy the knowledge that no one can get any more in batteries for the money than you.