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. There is an Eveready dealer nearby. .4fanujacturClt and guaranteed by NATIONAL CARBON CO., INC. New York: San Francisco Canadian Nallooal Carbon Co., Limited, Toroow, Ootario £\TEREADl 'Radio Batteries

'l- Tested and Approved by RADIO AGE 'l- 4 RADIO AGE for July, 1925 The Magazine of the Hour

ADIO CORPORATIO~ of America I'as com­ of Ra<:io Corporation's magazine. which, they assure pleted its "proof" that in adopting the nan;e us, is called ""Tireless Age," Therefore, a witness R RADIO AGE this magazine stepped on the testified that newsdealers get the two magazines cleven hoof of the corporation. The.' RCA contends all mixed up and that although one is published in that RADIO AGE, as a name, infringes on the name New York and the other in Chicago, dealers often "\\Tireless Age," a publication owned by the Radio send unsold copies of RADIO AGE to "Wireless Corporation. Radio Corporation last fall brought Age," The circulation manager of "\Vireless Age" formal action in the United States Patent Office at produced one letter in support of this contention. \Yashington opposing the application to have RADIO H e said he had looked hard for other documentary AGE registered as a trade mark. e\·idence of the uniyersal confusion between RADIO The S33,000,OOO group apparC'ntly held the fond AGE and "\\'ireless Age" but the one letter was the notion that RADIO AGE \\ould immediately yield best he could do. its rights, rather than go into a kg-al battle \,.'ith one Another Corporation employe swore toat at the of the Four Horsemen of Radio. On the contrary, Pageant of Progress in 1922 he heard SUbscription RADIO AGE engaged the services of se\'eral of tIle solicitors in the RADIO AGE booth telling the gullible best lawyers obtainable and we ha,'e seen the thing public that RADIO AGE was published by the Radio through. On ;\1ay 5, in the orporation offices in Corporation of America. This witness testified he Ne\\' York, the Corporation completed the taking immediately complained to the manager of the Pageant of testimony of its own witnesses. Th~ Corporation that the RADIO AGE solicitors were telling naughty labored and brought forth a pean ut tube. little lies. So, he testified, the manager threw the It was an imposing array of witnesses and we re­ solicitors out of the Pageant, and the RADIO AGE gretted that 1\lr. Sarnoff, ,ice president and general booth remained empty and free of guile from then on manager of the RCA horse, was unable to be prt'sent. until the show closed. This witness admitted he Mr. Sarnoff was busy preparing for a banquet. He is ne\'er brought these lllatters to the attention of the a banquetcc.'r of parts. No hungry Cassius he. officers of RADIO AGE, Inc., and that he didn't At the last Hoov('r conference, ha rles E . Erhstein report the incident to "'Yireless Age" until :'vlay, 1924 faced the representativ('s there pre::.ent in the int('r('st -almo~t two y('ars later. A long time to carry such of the Radio Corporation. \\"estinghouse, G neral a pineapple around in one's craw. Electric and American Telephone a nd Telegraph, 1\lr. Pierre Boucheron, general manager of the and told them the \yere the Four Horsem n of Radio. ad,' rtising and publicity departments of Radio The. name stuck. A fe w \yeeks later 1\Ir. Sarnoff Corporation and \'ice president and General manager and 1\Ir. Erbstein were present at a radio dinner in of \ Vireless Press, Inc., which publishes "\Vireless New York. 1\1r. Sarnoff approached 1\Ir. rbstein Age" for Radio Corporation, was easily the star wit­ and as ked in a gently sardonic tone: ness for Radio Corporation. He, too, thought "wire­ "Tell me; which one of the Four Horsemen am I?" less" and "radio" were identical in meaning. But on "PestilC'nce!" responded 1\ 1r. Erhstein in a flash, cross examina tion he admitted that since the action "Not famine?" inquired 11r. Sarnotl, somewhat against RADIO AGE was begun, the name of the taken Lack. magazine which is claiming it is suffering great injury "You, Famine? Neyer!" murmured 1\Jr. E rbstein. from competition by RADIO AGE changed its own So, on the occasion of the ta king of depositions name from "The IVireless Age" to "lY1'reless Age, calculated to prove that R:\DIO AGE is guil ty of The Radio ~i {aga::;inc." The change was officially unfair competition and is injuring the busin c~ of announced in the corporadon's magazine. last No­ '" Vireless Age," 1\1 r. Sarnoff was prepa ring for another \·emher. It was expla ined in this announcement that banquet. the old title was being retained in part so that the It was necessary that the RCA witnesses s\\ear to magazine might be more easily iaentified by those facts that would support the contention that the \\'ho were more specially interested in 'wireless. Yet words " wireless" and "radio" mean the same thing. "wireless" and "radio" mean the same thing! If this were prm'ed, Radio Corporation might hope A m an might be ob\;ou ~ ly right from start to to get some\\'here with its argument that in adopting fi ni sh in a controversy such as this and in the end the name, RADIO AGE, this magazine was appro­ might prove himself to he right. But he would, haye priating, in effect, the name "'\Tireless Age." which h en compelled to finance his defense and, though does not belong- to t his magazine, but helongs t o the he be right as a trivet , he could not obtain recourse New York monthly wireless puhlication, e\-ery share . against predatory interests who put him to all the of stock in which is owned by Radio Corporation. trouble and expense. That's why a 833,000,000 The witnesses then s,,'ore "wireless" and " radio" band of patriots hali a big adYantage in opposing an meant the same thing. Ko distinction whatever so individual of much more modest resources. Doesn't far as the man on the street was concerned. But it seem to be quite all square with our fundamental developed, on cross xamination, that all the \ itneslies ideals of equal opportunity and equal r~hts under the were 011 tIle payroll of the Corporatioll and therefore la\v, docs it? \\'e were ,,'arned three years ago that could not well he cri ticised if t heir expert views on if RADIO AGE criticised certain radio interests those the significance of words partook of the same general interests would step on us. Yet we criticised radio tendency as the yie,,'s of the kind and lm'ing old monopoly and we arc going to keep it up. If we Radio Corporation. still thrive where others faint, it may be because Our It also was necessary to prove that the use of the readers and newsdealers are not so confused as some name RADIO AGE was causing injury to the business folks hope they are. . RADIO AGE for July, 1925 The M agazine of the Hour 5 "Radio A ge" Popularity Contest Is N owClosedl

Race is Still Neck and Neck As Aldtne Starts the Official Count of L ast-M inute At the left i. the at ­ tractive .hield which Ballots; wiU be awarded the winner in the RAD IO AGE Popularity C on­ Name of test. which closed on June 15. Its .ize over­ all i. silt by eight in­ Winner to che.. and a detailed de.cription i. con­ tained in the article on Be Revealed this page by Mr. Ald­ ine. tbe persevcring Next Month Contest Editor for t..h.i~ magazin~ .

y THE time this issue of RAVIO October __...... _ .. _ ...... H. W . Arlin . KDKA By HARRY ALDII\lE Novembcr ...... _._...... _...... Bert Davis. WQJ AGE appears on the ne\\'s-stands, December...... _ ...... J ack Nelson .WJJD B the RADIO AGE Popul arity Con­ J anuary...... Art Lin ick . KYW Februa ry. Coon· Sanders Orchestra, KYW test will have ended, as only those votes t ration of the shield which will be award­ March...... John S . Daggett. KHJ received before midnight of J une 15 ed . the wi nner of the RADIO AGE STANDING TO MAY 15 will be credited to the total count of Popularity Cont~s t. From a background N ..me and Cla ssification Where Heard ca ndidates. of artist ic black will stand o ut in Karl Bonawitz, Organist._ ...... WIP. Philadelphia As this red ew is being written ( ~ Iay raised gold letters The \Vinner's Na me,a nd B ert D a vis. E ntertainer...... W QJ, Chicago Bill Hay, Announcer...... KFKX, Hastings 16,) there st ill remain a full t hirt y days, t he inscript ion, " First Annual RADIO John S . Daggett, Announcer. __ .. KHJ. Los Angeles during which period t he winner will he AGE Broadcast Ent erta iners' PopUlarity H . W . Arlin. Announcer_...... KDKA. Pittsburgh Coon-Sanders' Nightha .... ks. Orchestra, KYW. Chi. definitely named, and judging from the Cont est-192-l-25. " Jack Nelson. Announcer ...... WJJD. Mooseheart hea vy voting which has t a ken place urro unding t his will be a plain gold Art Linick, E ntertainer. __...... KY\V. Chicago during the past thirty days, no candidate Harry M . Snodgrass, Entertainer ...... _...... __... .. border con(orming to t he sha pe of t he WOS. J efferson City is yet assured of the coveted position shield. The gol d plat e will in t urn be Ford & G lenn, E nterta iners. __ ...... WLS. Chicago at the head of the list. At no time in t he mounted on a dead b lack bevel-edged Duncan Sisters, E ntertainers...... K WY. Chicago history of the cOntest ha\'e the three Lee Sims. Piani. t ...... K WY. C hicago \\ ooden plaque, to which is attached a Lambdin K ay, Announcer...... WSB, Atlanta leading candidates been so closely cha in for ha nging. The size, overa ll, J. R emington W elsch O rganisL_.... KWY. C hicago bunched. is si x by eight inches. f'red Smith. Announcer ...... WLW. Cincin nati T o further complicate matters, "Uncle E . L. Ty.on. Announcer._. .. .. WWJ. Detroit \Vhi le se\"e ral ideas were o ffered for H ired Hand. Announcer...... WBAP. Fort Worth John" Daggett, ' way out on t he Pacific the design of the shield, the o ne accepted " Sen" K aney. Announcer ...... KWY. Chicago Coast, has jumped from ninth to fourth seemed to conform most to the princi ples N ick B . H arris. Enterta in er._. .. . KFI . L os Angeles place, where he sta nds menacingly , J erry Sullivan. Announcer·E ntertainer. W QJ . Chi. of dign ifi ed simplicity. a nd was t herefore E d ward H . Sm it b, D irector-P laye r ...... offering dangerous competition to t he t he most forceful ma nner of declaring to WGY. SchenectadY three popular leaders. By referring t he world the winner of t he contest. Charle . E . E r b stein. Announcer._... . wT AS. Elgin further to the "Standing to May IS" Wendell Hall. Entertainer .....WDAF. Kansas City FOllowi ng is t he sta nding of the can­ Howard Milholland, Announcer...... KGO. Oakland it will be found that Art Linick has also didates as they are lined up at present; Scottic:h Rite. Orche.tra...... KGO. Oakland bettered his position by stepping one B anks Kennedy. Entertainer.__ . WEBH, Chicago' more round toward the tOp of the ladder, W INN ERS OF PRECEDI NG M ON THS S . Ha.tings. Announcer.. .KFI. L os Angeles July... .Duncan Si.tc:rs. KYW Robert Bontel. Announcer .. .WEBH. C hicago from eighth to sc\'enth place. Augu . t ...... Bill Hay. KFKX Arion Trio. InstrUmentaL...... K G O . Oa kland On this page will be found an ill us- September.. Karl Bonawitz. WIP Gold Du.t Twins, Entertainers, WEAF. New York 6 RADIO AGE for July, 1925 The Magazine of the Hour

Mr. Manufacturer Would you write 100 letters to 100 people to reach just two men? Then, before you invest your advertising dollars-THINK!

An analysis shows that pUblications of general circulation, newspapers and magazines, devote less than 2 % of their reading columns to Radio~proving that in the opinion of This Association their own Editors less than 2 % of their readers are inter­ is comprised of ested in Radio. In fact, many general publications carry no the leading Ra­ Radio editorial matter. Therefore~98% of your investment dio Magazines. is lost!

On the contrary, the Radio magazine offers 100% Radio editorial- attracts 100% potential buyers.

Spend your advertising appropriation in Radio Mag~zines. Be sure of the greatest possible return on your advertising dollar. Radio Magazine Publishers' Association, Inc. RADIO AGE is a member of the Radio Magazine Publishers Association, Inc. © Cl B661371 RADIO AGEJor July, 1925 The lvJagazine oj the Hour 7 rSI IG~"I IS~SI I"~SI I'" "3~BI I~I I@I I~I "'1 ~ , ~ 1 l ,., ~@ , <{~Z / ~ I:) , " ,' ' ~ I:) ~ :Jtie Maga3ine ifthe Hour ~ l:)l MBu~tn!.';~~~ageT A t::~,te"l;~ol:~:~~:!~on Freder~~to~' Smith mi· l 1:)' Ie' '1:)1 11:)1 '[!Ii I[!Ii I[!I , I~' '[!I' '[!I' '[!I' '1:)' '1:)' I~~I What will Tomorrow Bring- Four, Five or Six TUBES? Our readers' flote is requested upon the By ROSCOE BUNDY in t he way of improved performance, number of tubes that will prove most popu­ T~e ra~io, frequency steps were coupled lar during tile coming radio season . Will With primitIve untuned radio frequency economy rule 7.iJuh the use of the four tube transformers that were little better than set, will we adhere to the present popular coupling condensers, and which peaked five tube set, or will we attain quality with Trend Seerns T o Be badly on some particular wavelength, the six tube set regardless of the increased generally on the wavelength of One of price? This is a question that the radio Toward Clear Music the local stations that you we're trying dealers and RADIO AGE would like to to tune out. have answered by oftr readers. At this stage of clevelopment the addi­ 7. Secondary Tap Switch Knob. t ion of tubes was a serious proposition, T was not so v ery long ago that the 8. Grid variometer Dial. for the tubes then drew anywhere from three tube regenerative receiver 9. Plate variometer Dial. 0.75 to 1.0 ampere each, so that a four I marked the height of affiuence in 10. Variable Grid Leak Dial. tube outfit would draw up to four am­ the radio world and that the owner of 11. Detector Rheostat Knob. peres total, or four times as much " A" such a super-set was enviously regarded 12 . First Stage Audio Rheostat Knob. battery juice as the largest tubes of the by his fellow B. C . L.'s who were still 13. Seconcl Stage Audio Rheostat present day. getting their music via the single tube Knob. You could easily run down a freshly and the crystal set. In those days we 1-1, Battery Switch Knob. charged battery in the course of one could consistently get coast-to-coast ev~ning and then wait over for a day reception or its equivalent On three The Man Pays This Time! whIle you recharged your battery with tubes, and with the tubes retailing at Oi\lE price to pay for an attempt at some ineffective trickle charger, generally 56.50 each and the receiver itself hover­ S selectivity! A maze of confusing of the buzzer type. Those were the days ing around the $200 mark, the old three controls that were not half as effective when the Luzz of the charger was con­ lunger was held in the same regard as as the three tuning dials and two rheo­ tinuous in the land and when the battery the most elaborate five tube set ·of the stats that appear On the panel of the spent as much time On the charger as 'on present day. I t tuned as broad a s a present time tuned radio frequency re­ the receiver. You would feed it five barn, howled like a fiend and mushed up ceiver, and which required considerable amperes all day only to have the receiver the signals, but in her day the old three practice before they cou ld all be Lrought drain out all of the profits by 12 o'clock did her stuff, as the many DX records of into adjustment. p . m . 1921-1922 will test ify. The constant urge for more distance There is no doubt but what the 0.25 Repeated refinements in the regenera­ resulted in the first appearance of radio ampere tube of the 201A type made the tive circuit, brought the three tube re­ frequency steps which at that time were multi-tube set a practical possibility, generative up to a high degree of effici­ simply auxiliaries to the original regenera­ an (I that further increases in the number ency in bringing in distance, but in the tive receiver and increased the complica­ of tu bes will also depend upon ·the de­ craze for distance we sacrificed selec­ tion considerably without much return velopment of tubes of the 199 type which tivity and tonal quality. They were will make dry cell ope ration practicable superlatively sensitive to weak signals, with five tubes or more. but as most of the old timers were of The Reflex Enters the single circuit type or were provided with the old inefficient , vado-coupler, WING to the necessity for battery they ' were very broad-tuning and could O conservation with the old tubes, the not possibly cope with the present day coming of the reflex circuit was heralded congestion of radio traffic, even though with joy and much of 1923 was devoted they did have from five to ten t uning to the development of the reflex circuit controls. There were more dials and OET AUO AVO by experimentally inclined amateurs. less selectivity ' in 1922 than at any Partly for the reason that the radio F/(:;.1 REGENERATIVE' other time in radio history. frequency transformers of 1923 did not Just as a review on the subject of '\1;7 measure up to the standards demanded tuning controls let me list the dials and \~I RF RFX by the reflex, and partly for the reason knobs that commonly appeared on the t__ /_x.--,\/-;- .... , _ that reflex· principles were not well under­ panels of the old time three tube three stood, the reflex did not attain the \ J popularity that was expected by its circuit regenerative: \. I ..... _-" sponsors, and there was a decided ten­ 1. Primary Variable Condenser Dial. dency toward falling back On the old 2. Rotor of Vario-Coupler Dial. reliable regenerative circuit, with which 3. "Tens" Tap Switch Knob. RG.c.R~F'-EX almost any beginner could expect to get 4. "Units" Tap Switch Knob. SOme sort of results. There were many 5. Series- Parallel Switch (Some- Figs. 1-2, Three Tube Circuits Com­ reflexes that gave phenomenal perform­ times). monly Used. Dotted Line Represents ance, but in the main, the radio public 6. Secondary Variable Condenser Radio Frequency and Solid Line is Audio SOOn discovered that the reflex of that Dial. Frequency. time was not an ideal circuit for the 8 RADIO AGE for July, 1925 The Magazine of the Hour novice and that special precautions were accompaniment of the shrieks and wild fixed primary coil. In fact, a mo dem necessary that rather took it out of the wailings t hat were prevalen t in the three-tube circuit with this sort of tuner home-builder's province. regenerative era and hear music. ~nd is fully the equal of an old four tube Things hoyered around this condition voice wi t hout a background of hiSSing using the vario-coupler, and is not half for so me time until a change in radio and frying sounds that formerly de­ as bothersome. Further, it can be took place with the appearance of the tracted so much from t he enjoyment of a "logged" so that each station comes in on five tube neutrodyne, the father of all program. In clarity of tone, the five a definite dial position, which was not the numerous five t ube " dynes" now on tuber was nearly equal to the reflex at formerly the case, making tuning certain the market ancl the salvation of the its best, and the problem of perfect and prompt when provided with a table reflex principle. The neutrodyne was reception was therefore put up squarely of station wavelengths and a well pre­ not the first tuned ra.-lio frequency to t he manufacturers of loud speakers. pared "log" of the corresponding dial outfit by any means, for we had plate It was now a question of ,leveloping a positions. Logging is an essential with a tuned CIrcuits long before this, but it horn t hat was a fit running mate for the modem receiver of any type. was the first stable five tube radio fre­ receiver. Out of this ~erfection in regeneratives quency set that could be built with any New Twists Developed spr~ng. a hybnd four-tube circuit type degree of success by the average home­ which IS very popular today. This con­ builder. N the meantime, we must not forget sists of a stage of tuned radio placed in With all due respect to the neutraliz­ I tha t all t his improvement also stimu­ fro~t of th~ three tube regenerative ing principle as a pplied to the suppres­ lated experimental work on .the regenera- whIch both I nCreases the distance and sion of self-oscilla- selectivity and also tion in the radio fre- counteracts the ten­ q uency stages, the dency of the regen- real advantage of erative unit toward the neutrodyne, ac­ causing annoying cording to my idea, RADIO AGE BALLOT aerial radiations. lay in the construc­ The I3rowning­ tional details such (How Many Tubes Do You Prefer?) Drake circuit is a as the tuned ra.lio prominent example frequency transfor­ BALLOT EDITOR, of this type, which mer and the aper­ Radio Age, Inc .. consists of one iodic or semi-aper­ 500 N . Dearborn St., stage of tuned radio iodic coupler. By Chicago. IlL freguency amplifi­ these units we coul(l On the following list I have checked off tte radio receiver that best catIon, regenerative approach a degree fills my requirements. and have written my reasOns in the blank space detector. and two of selectivity hi ther­ following the specifications. stages of audio fre­ to unknown, by CLASS 1. THREE AND FOUR TUBES. (a) Three Tube regenera­ quency amplifica­ means of very tive with transformer coupled audio stages, (b) Four Tube tion. Both the simple units; and Regenerative with resistance coupling, (c) Three Tube coupler-tuner and further. we could Reflex. (d) Four tube reflex with loop, (e) Four tube regen­ the radio frequency peak our radio fre­ erative with One stage of radio frequency. transformer are quency amplifica­ CLASS 2. FIVE AND SIX TUBES. (a) Five Tubes, two stages of special adaptions of tion on the desired radio, detector, and two stages of resistance coupled audio. the tuned coils wa velength instea. 1 (b) Five tubes, One stage of radio. regenerative. detector originally used in of adoptingthe com­ and three resistance coupled stages. (c) Five Tube Reflex the neutrodyne, promise ampli fica­ with loop, (d) Five Tubes. Two stages radio, regenerative although much more tion of the older detector and two stages of transformer coupled audio, (e) efficient and selec­ fi xe d transformer. Six Tubes, Two stages of radio. regenerative detector. and tive because o( the Again, this was the three stages of resistance coupled audio. (f) Six Tubes, two absence of electro­ first fairly high radio, detector, three stages transformer coupled audio. static coupling be­ power set within CLASS 3. SUPER-HETERODYNES. (a) Six Tube, (b) Seven tube tween the primary reach of the aver­ (c) Eight tube. and secondary coils. age amateur and the Such circuits are first practicable set REASON FOR MY CHOICE_ __ .. _. . __ .. _.. _.. __ ...... ___ ...... ______. __.___ .. _...... __. __ ... _ rapidly increasing with more than in favor, for they three tubes which have great d istance had appeare d . getting qualities for Tonal quality was the number of tubes improved as well a s employed and are distance and selec­ Name__ . __ . __._ ._ .. _._ ..... ______. ______..__ si mple and cheap to tivity. and in gen­ Street or R . F . D _ ___ ._.... build. eral it took the radio world b y City._._ ... _. ____ .. __ _. _._. __ . __ ... _.. ___ ...... S tate._. ___ .... _._ .. _. ... _... ____ .. _. ____ _ Revised Reflex Circuits storm in spite of t he NOTE: If you do not wi.h to tear this blank out of your bonk. • end 3 brief note covering c ost of the fi v e the above points. It will do just as well. UR reflex cir­ tubes, which a ver­ O cuits now took aged about S5 .00 on new life with the each at that time. advent of the aper- The rapid increase in the popularity t ive and refl ex circuits in which many of iodic type coupler and tuned air core of the neutrodyne brought a perfect the radio frequency construction details rad io frequency transformers, with the re­ flood of five-tube t une. I frequency sets were employed. Fo r example , t he aperio.l­ sult that the modern reflex much more on the market with all sorts o f weird ic type coupler was now e mploye d on nearly approaches its theoretical advan­ methods of suppressing free oscillations. regenera ti ve a nd renex ci rcuits a s well as tages. The radio frequency component is The question of hattery current consump­ with t he t uned ra dio frequency out fits, now tuned by the same air core transfomer tion coulel no longer be leveled a gai nst at one t ime im pro\·ing their performance units employed in the tuned radio fre­ these circuits, for the 201 A tube gave a and sim pli fying· t he controls. The old quency sets with greatly increased range total consumpt ion of only 1.25 a mperes vario-ceupler became a thing of t he past. and ~ t a b i lity . By the same· means, ohmic against the 3.0 amperes formerly neces­ Single control regenera t ives became more resistance is reduced, selectivity increas­ sary with the old tubes in the three and more common. bot h wavelength ed, and wonderful results are being t ube regenerative receivers; hence we and regeneration being somet imes con­ obtained with only a few tubes. Two could run longer per cha rge with the trolled by a single varia ble condenser tube reflex sets with coast-to·coast re­ new five tube combination than wi th t he while taps and tap switches were placed ception and loud speaker v olume on 500 old detector-and· two-stage outfit. in the discard. mile stations are not uncommon where Under the new system, coa st-to-coast A rege nerative circuit of the new era the improvements have been added. reception on the loud speaker was so consisted of a dial for tuning to wave­ \Vhere fixed R. F. transformers are used common as to cause 'no Comment and lengt h, and perhaps another dial for we now have true magnetic coupling in­ we could bring in real distance through the t ickler. This was all there was t o stead of the capacity coupling had in the the most powerful, local broa(lcasting the proposition and we not only simpli­ older types, and with modern untuned stations with ease. For t he first time we fiecl ·things, but also obtained better transformers we ha \·e excellent perform- could bring in a station without the selectivity, tone and distance with the ance. RADIO AGE for July, 1925 The Magazine of the HOllr 9 Three tube reflex circuits, using tuned than that of a corresponding grade of radio frequency transformers through­ radio fr equency or reflex receiver, and out, give fully the results of a five tube this item, of course, is sufficient to rule straight radio frequency set when proper­ it out among many classes of radio fans. ly built, and have the advantage that \\"hen the D X fe,"er was at its height, they can be opera ted with dry cell "A" with every effort bent toward getting batteries with success. There are a distance a t a ny cost, very little atten­ number of "kit-sets" or complete sets of tion was paid toward eliminating dis­ parts now on the market for building a greeable noises or for improving the reflexes of this type, so that the construc­ F/G.3. ReGeNeRATIVE tone of the receiver. In fact, the noise tion of a reflex no longer is a problem for in the early broa dcast receh'ers, coupled the advanced student of radio, but is with the crude loud speakers of that entirely practicable for the rawest novice. period, wa s very effective in holding This is in contrast to the conditions ex­ back prospective customers who possess­ perienced in the old days when the ed the most elementary sense of tone. builder of a reflex frequently had to buy The field was entirely in the hauds of the enough material for two sets before he distance fanatics, and they continued could find parts that would match up to hold it until the coming of .the tuned and function properly when hooked up radio frequency sets, with their improved in a reflex circuit. reception, made a n appeal to another In writing the above paragraph it Figs. 3-4. Four Tube circuits, Regenerative, class of listeners. The latter formed the brings to mind the great advantages \'(Iith One Radio Stage (J ) and Reflex Four bulk of those who purchased radio dur­ enjoyed by the present day radio set Tube (4) ing the past year; people who objected builder compared with the trials and to listening to the mangled remains of a tribulations of the old-timer who had sonata, just so that they could boast of little to work with in the way of materials the development of six and seven tube hearing some peanut station 1,500 miles and still less data. In the old times, a super-hets which give full y as good per­ away. Better have good, clear. local smudgy illustration cut out of a news­ forma nce as the standard eight-tube reception on a crystal set for these pros­ paper with an exceeding inaccurate de­ type, and have the further advantage pects than a mushed up mess coming in scription was considered a "find," and that they are more compact, cost less, and from a dis ta n t station. with a few yards of barb wire and other take less battery current. Satisfactory In addition to the inherent noises of miscellaneous junk, a valiant attempt results are being had with six and seven the regenerative receiver, which were was made toward the construction of a 199 tubes, which brings the set well down really not always so bad on the head­ workable receiver. Nowadays, the build­ toward the limits of dry cell operation, phones, the early audio transformers er can obtain accurate apparatus put . and \\·ith such sets we obtain wonderful were far from being perfect and added up in complete kits so that an hour's work selectivity and loud speaker operation their din to the collection of noises an­ wi t h a screw driver and pliers is all that over great distances. Their tone value nexed in the detector stage. High ratio is necessary. Each wire is cut to length is of the best, and with a little experience audio transformers with their distor­ and a detailed series of picture diagrams they are easy to tune and handle. In tion, poor design and other factors made gives all the data that anyone could fact, two condenser dials and a potenti­ life miserable for the musicia n who was possibly ask for. In one way, howeyer, Ometer are the only controls necessary. forced to hear the blasting and blare of all this spoon-feeding is a bad proposi­ Super-heterodynes are essentially a the old horns or noise chutes. Improved tion, for it is getting to such a point that type designed for operation on a loop transformer design, together with the the experimenter is now too dependent aerial, and for this reason they make a use of low turn ratios, has greatly im­ upon others and is rapidly losing his great appeal to those \,'ho have no chance proved these conditions so that there spirit of self-reliance. Here at RADIO to erect an effective o.utdoor aerial. IS little distortion or noise within the AGE, we find that the slightest omission Certain radio frequency and reflex re­ receiver itself. Further, the introduction in a description or in a drawing is ceivers will also give good results on a of resistance coupling in the audio stages sufficient to throw him all out of joint, loop, but the super-het is particularly made another step toward perfect tone, and instead of trying a few simple experi­ adapted for this kind of service, and to a so that the t endency of today is rather ments that could be performed in five great extent, its selectivity is due to the In the direction of clear, undistorted minutes, he will write in and calmly wait directional properties of the' loop aerial reception than toward mere distance. for some one to work out his simplest with which it is use,!. Its only drawback [ am thoroughly convinced that future problems for hi~. is its cost, which is considerabl y greater improYements in radio apparatus will be along the lines of The Super- tonal improvement Heterodyne and that the buying During the past public is more inter­ year much work has ested in tone quality been done on the than in the attain­ development of the ment of distance. s upe r - het erodyne A good, clear nat­ principle and great ural tone with mod­ progress has also erate distance get­ been made along ting qualities; low these lines. Properly current consump­ designed, and with AUD tion so that dry the proper mater­ batteries can be em­ ials, the super-het is ployed; stable per­ the ki ng of all re­ formance wit h 0 u t ceivers, but once ner v e racking again we warn the shrieks and howls, novice that he '-r 7 and perfect select­ should obtain his \ I I ivity are the char­ apparatus in kit-set acteristics of the form to insure all of 'V _~ salable radio recei \'­ the parts being prop­ " "­ er of the future. , / ,.., \ erly matched so that \ II I The experi men ter they will work to­ -- r---- - ,- and the DX hound gether. To assemble \ / have already been a super-!teterodyne ' - - _/ served, so that our out of a miscellane­ RF DET AVD AvO AUD next appeal is to ous mass of un­ that class of music matched parts of FiG. 6. ~ R.;: RcGENER..4TIVE lovers who have not different makes re­ yet seen fit to buy quires a considerable radio equipment. amount of skill and The reproduction experience. must be fully equal Continued experi­ Figs. 5-6. Five Tube Circuits. Two Stages 0/ Radio Frequency and Audio (5), and to that of the hest ment has resulted in Resistan.ce Coupled Five Tube With One Radio Stage (6). modern phono- to RADIO AGEJor July, 1ns The Magazine oj the Hour If this were not so, then everyone would place their check mark opposite One of the more powerful and costly sets and we would be as much in the dark as ever. Mark your ballot candidly; we want to know just what is on the minds of our readers. Place your check mark opposite the type that you most desire RF RF DET AUD 4UD ALJD and then make a note of why you prefer this particular circuit. This IS as much Fi6. 7. Two. ST//GE A31olo ANPLI,rlcF to your advantage as to ours and is not "T' an advertising scheme--we want to \I/~ know. T DBl.FIi'EO. HARI-10N . DET A AUO The Universal Need \.JD \ {DA~~LtF1E'" O~CILL. ~]!~ OUD-SPEAKER operation is almost _I E9 E9_ -- .\: - ~ ""'N '.-/ Q__ l e ~ I Q • ~ I \ I r-- r--t---"'--+_+--L--t-~ L a universal requirement with the J , - - "'-~ " , / - receiving set of today; hcnce, we must t '>--~ , ~-..." t " ; ~ 5 G always be assured of the equivalent ~ t~ __~_ ~~/3 of at least two transformer coupled audio , j frequency stages. So far as marketable '-.---... ------sets go, the days of the headset are prob­ ably gone, even, on distances that were N6.8. SU?ER-#eTEROOYNE considered of the DX order several THE ,4BOj/E SIX TUBe SUPcR-,.¥,ET.EROOYNe /$ OF Th'E S.ECOIVL> years ago. Even with portable sets, we H.4R MO/YIC Type IN whllCh' -rh'E F/R'ST TUBe /S REF LEYEo see provision for the loud speaker and in AT BOTH L.O/YGANO SHoRT RF. W,.4VEL £ N6rHS. most cases the loud speaker unit is built into t he set p ropcr. Shorter and shorter acrials, or aerials Figs. 7-8. Six Tube CirclIits. T U'O Stages 0/ Radio W'ith Resistance Coupling (7), S uper-heterodyne ( 8). of the indoor typc, incrcasc with the increasing numbers of broadcasting sta­ tions, for a short aerial is almost a graph, and this should not be so difficult t ive with good distance getting qualities to attain, as there are certain mechanical­ but only fair tone value, to a four tube necessary adjunct to selectivity in these ly connected linkages in t he phonograph set with slight ly better distance and tone days. Loop aerials are very popular for which do not exist in the raclio; hence providing that the latter. only cost a few much the same reason, and also because sound without distortion should be mOre dollars more? Would you prefer these they avoid the trouble of erecting an perfectly accomplished where the trans­ sets to a three or four tube reflex with outdoor structure. mission is performed electrically thall wonderful tone value, great volume, and There is probably not any increased where loose jointed mechanisms are em­ moderate dil!tance? I am omitting refer­ risk due to thunderstorms; in fact, the ployed. ence to the one and two tube sets which risk may possibly be less, but they are are really for the head-set and can only Resistance Couplin~ be used on the speaker with powerful not desirable. ERFECT as the modern audio fre­ local stat ions. P quency transformer may be. there is If you had more money to spend, would Talks on Cuisine even less distortion with resistance coup­ you spend it on the conventional five ling, for the amplification is always in tube tuned radio frequency set with Station KYW exact "straight-line" proportion to the transformer a udio stages, or would you SERIES of eight talks closely re­ drop of potential over the r ~ sistor coupler. like to add another tube for resistance A lated to the cuisine in your home is As with other items in radio, however, coupling so. t hat you would have the being given over \Vestinghouse station the resistance coupling met-hod is a com­ superlative in tone v alue for the R. F. promise that is not without drawbacks class of receiver? How would a five KYW, each Thursday at 9:15 p . m. until of its own. In the first place, we must tube reflex operating on a loop strike you? June 25, which will be the date of the use three amplifYing tubes with the Now for the third class, which costs last talk. resistor to get the degree of amplifica­ quite a little more than any of the others. KY\V has secured the co-operation cf tion obtained by two tubes with trans­ We speak of the super-hetrodyne with John C. Cutting, to give these talks. former coupling; and in the second place, its loop aerial, from six to eight tubes, 1\lr. Cutting has been telling the New we must use at least 135 volts of UB " a nd with it s excellent tone and volume? battery instead of the conventional 90 Do you believe t hat these increased York women, over \VJZ, how to manage volts used wi th the transformers. I t is virtues compensate for the additional their homes and husbands. This was the same here as everywhere else. If cost over those offered by the five and six a weekly feature in New York for over we wish to gain the benefits of perfect tube sets of class two? That's what the sixteen months, and his thoughtful and reproduction, we must pay the price of manufacturer wi shes to know, that is valuable home hints, SO delightfully admission, a nd according to my ideas, what we wish to know, and that is what put forth, proved to be of such value the lletter quality ohtained by the will affect the market in which you are that the same propaganda is going to resistors fully compensates for One extra to buy your radio. There is only One be exploited in Chicago, over West­ tube and one extra block of uB" battery. way in which public demand Can be The application of the resistors is simple detcrmined and· tha t is by asking the inghouse station KYW. and reasonable in cOst. buying public to vote On thei r opinion Mr. Cutting, who is secretary of the In what is to follow, add one tube to or desires just as we are doing here. Meat Council of Chicago, began his the set for resistance coupling where \Ve have guessed until we are blue in the series of wcekly talks from KYW on transformer coupling is specified. Some face, but as yet have come to no COn­ May 7, at 9:15 p. m . having chosen increase in amplification with little or no clusion, and there a re a whole lot more for his first subject "Filling Four Stom­ efTect on the quality Can be had by com­ in the same boat with us. achs With a Dollar Bil1." 1.1r. Cutting, bining resistance and transformer coupl­ In making your choice, please consider who enjoyed thc prestige of being the ing with one transformer stage and two the many factors that enter into the resistance coupled stages. proposition. The question of tube only man on WJZ's program who dis­ cussed subjects dear to a woman's heart, How :Many Tubes? economy, compactness ancl portability, dry cells versus the storage battery, first has a faculty of putting these talks over At last we are getting back to our cost, distance, tone, v olume, selectivity, with the enthusiasm and pep required oril;inal question, the suhject of this loop aerial or outdoor aerial, and the cost to promote his idea. He will tell young article, after wandering around among of maintenance. There is some one com­ wives how to spank up a roast or hem­ the various types· of radio receivers. bination of these factors that will suit stitch hamburger in a way that will \Vhat is your preference, or rather, what your conditions best and we wish to sort of a radio outfit would you buy if know what it is. We have divided the bring them the eternal love of their you were to purchase One tomorrow? receivers into three classes according to respective husbands. With a limited amount of cash available, price, for we believe that price is the de­ Tune in and let him do his stuff. would you prefer a three tube regenera- termining factor in the majority of cases. KYW, Thursdays at 9:15 p. m. RADIO AGE/or July, 1925 The Jfagazine of the Hour 11 ((Formulae and Tables for Testing and Plotting Charts for Vacuum Tubes Used in Radio Reception Learning Vacuum Tube Characteristics

By H. FRANK HOPKINS The milliameter shown above shows the plate current characteristic in miUiampercs. HERE are numerOus characteristics will only give a fair idea oJ how a tube of vacuum tubes used in radio re­ will act. They will sometimes show ba ttery terminals. Tile negative terminal T ception and transmission that may a good plate current curve, but fail of . one connected to binding post (C - ) be determined, but which have no to perform efficiently when in opera­ t he positive terminal of this and the value to the average radio fan. How­ tion. Therefore, it is worth the differ­ negative terminal of the second "c" ever, there are a few of vital import­ ence in price to have a set that will battery connected to binding post ance to all users of vacuum tubes and show the filament current or voltage (C+ -) and the positive terminal of it is the writer's intention to make clear and the grid bias voltage in addition the second " C " battery to binding such of these characteristics which are to the plate current. post (C+). of importance to the fan so that he For this article, the RADIO AGE The filament rheostat (R) is moved will be able to plot curves or charts test set was used. It consists of three to its off position, a tube placed in the and match his tubes as easily a s he meters; a filament voltmeter, a grid socket (T) .and the set is ready for tunes his receiving set. volt meter and a plate milliammeter operation. By moving the switch (BS) The equipment required for this work with the necessa ry resist ances to vary to point (-) and clo sing switch (GS) is a good vacuum tube test set, such as the filament and plate voltage and grid a negative grid bias voltage will be described in the l\Iay issue of RADIO bias voltage as desired. shown on the two-scale voltmeter (GI\1), AGE. An instrument such as this It was prepared for operation by this grid bias voltage may be varied may be built at a nominal cost or one connect ing an itA " or filament battery at will from 0 volts to 7Yz volts by similar may be purchasetl ready made of suitable voltage for the tube under moving the potentiometer (GP) until at a good range of prices, from the test- to terminals (A BAT +) and the meter shows the desired voltage. simple One-meter affair to those having (A BAT - ). By moving the switch (BS) to the (+) a complete set of meters. A " B" or plate battery of ninety point, a positive grid bias will be shown Vults was connected across the bind­ on the meter (GM) and will be varied The One-Meter Tester ing posts (B -) and (B90) with taps as above. HE one meter tube testers are at 22 Y2 volts, connect ed to binding The swit ch (PS) and the rheostat T limited in their use, however, and post (B22), 45 volts t o binding post (B R) regulate the " B" or plate' battery outside of a plat e current curve at a (B45), and 67Y2 volts to binding post voltage. By moving the switch (PS) fixed grid bias, no other features may (B67}. Two 77-'2 volt " C" or grid to terminal (1) and moving the rheo­ be determined. This type of test set batteries were connected to the " C" stat (BR) a plate \oltage range from

-, '

Figs. 1 and Z. Fig. I shows the typical curve of plate current voltage, whllt! FIg. l shows the typical curves of grid and plate characteristics, the result of tests described in the accompanying article. 12 RADIO AGEjor July. 1925 The J1-Iagazine oj the Hour negative reading on the meter (6m) and the plate voltage will be adjusted to 0 ,·olts. By moving the rheostat (BR) the plate voltage is increased. A reading will be taken from the milliammeter and a point corresponding to this reading and the reading of the plate voltmeter (PF) will be marked on the cross section paper, as in the chart (figure one), This reading - with 5 volts on the plate, showed a plate current of about .1 milliampere, At 10 volts it read practically the same, and so on, gradually until 20 volts was applied and read at .3 milliampere. At 25 volts the plate current was about ,5 at 30 ,7 and at 40 it was 1.2 milliamperes, I t increased ra pidly until90 volts showed The w 'o-scale vC'ltmeler . slwwing the grid a plate current of about 4.3 milli­ bias voltage. amperes-which is a ye rage for a tube The 0-10, 0-100 scale voltmeter, which of this type. shows the filament voltage and plate volt­ age, respectively. o to 22 31 volts is obtained, to point \Vhen all of these points are marked (2 ) from 22 31 to 45 volts, to point (3 ) they will be joined by a line running from 45 to 67 31 volts and to point (4) through each, and a completed plate showing 1.2 milliamperes at 0 volts from 67 31 to 90 volts. This voltage current curve as in figure one will be negative and so on down until .1 milli­ is read on the meter ( I'F) by moving made. Simple, isn't it? This perform­ amperes Was obtained at slightly over 4 the transfer switch to position (4). ance may be repeated-on the same volts negative "ias. The filament voltage \\·ill be read on chart, at different grid bias voltage­ This curve will show the best "e" the same meter (PF) by moving the say a 1 1-2 volt negative and a 1 1-2 battery voltage or grid bias for a tube at transfer switch to position (3 ). The volt positive bias, thus giving a complete various plate voltages, and it may not be filament voltage is varied by the rheo­ plate current story of the tube at various amiss to say that as we add to the plate stat (R). operating conditions. voltage, the higher the grid bias voltage may be, several curves may be made on Plate Current Curve Grid Characteristic Curves one chart for this characteristic at OR the first test, we will use a 3-4 rrO make a grid characteristic curve- various plate voltages, as shown in F volt 199 type of tu be-placed in the figure 2, the plate voltage will be Figure four, on page 12 of RADIO AGE socket (T) by use of an adapter. This set at 40 volts- the grid bias voltage for ~lay , 1925. is a high vacuum receiv ing tube with the will be adjusted until the meter (G ~1) A filament voltage curve may be filament normally operating a t 3 volts shows 0 with the switch on point (+). made and a filament current curve also and a filament current drain of .06 The reading of the milliammeter (~lA ) if an ammeter is included in the test amperes or 60 milliamperes. This type of will be located on the chart as before­ set. This will be plotted from periodic tube is most used in super-heterodyne a nd readings for each fraction of a volt readings as in the other curves, and will receiving sets and is by far the most will be spotted- as in figure two. The ma ke it possible to show an emission critica l olf e, -eryday t ub .. s. 40 volt cun'e showed a plate current of curve (Figure 3). This is one of t he A piere of cross section paper will be 1.2 milliamperes and a t 1 volt (+) it factors so important to users of vacuum prepared by marking the plate voltage read 1.5 milliamperes and so on to 2 tubes, as the life of a tube depends upon scale on the lower edge and the plate volts ( + ) it read 1.8 milliamperes. Going the proper emission of the electrons from current scale on the left edge as in figure back to 0 volts and shifting the switch the filament, and is usually ended by a one. The filament voltage will be ad­ (BS) to a negative bias, the readings were decrease ·in emission, necessitating ex­ justed to a point just below 3 volts, taken the same as above, except they were ces!;j ve filament voltage to keep it in say 2.8 volts, the grid ,,'ill have a 0 v olt im-ersely proportional to the grid , -oltage, (Turn to page 5.3)

!'t . +r f+ I I- I- . J-: It--!-:- " 04- . .j.. 'Ht · lli: +: p~.n ~ .~ - + ' ht~. i.o 7~·"t- ~ I Q . . -, , ,.-r-. ....,..... to i"h' 4.l-1, ~ I. z. t +ri= . , ~ iftt T H- il ... I.. ~ I L I'!i ~ + ~ ~ +! , r + • . ~ I ~I-I- 'T-H-. . ~ . h' . 1 ~ ~ , .. .. Hi' + ~: ! , - -': ' ~ ' , .~ h- .;.. . ~~ " -h l-"i- :±,R . ,.... II :(l'r -I IHil

FIgs. 3 and -I . F Ig. 3 t.s an example oj un em Iss Ion curve. a .s de.scnbeJ In Mr. flopklTw' arue/t' . Flg . .J r/!tleals the difference between a good tube under normal operation and a poor lube under the .same ccnditions. RADIO AGE for July, 1925 The Magazine of the lJour 13 How Much Coupling is Necessary?

Coupling can be corutrued as the method by which energy is trarujf'rramplifier, or again audio energy passing bettween audio stagc.s. Coupling passes the energy across in each case, Big Advantage in Having a Variable Coupling Scheme to Enable Adapting the Receiver to Different Aerials; Suiting Coupling to Varied \Ylavelengths a Real Problem

OUPLI:\G" is a broad term in A co upler as in " A " may be wound on its interpretation. It signifies the By BRA] NARD FOOTE one piece of tubing, with a primary coB C method by which energy is of as many turns as are necessary for the­ transferred from one radio circuit to individual case. To get the maximum of another. Whether it be the energy from large aerial will increase broadness and a volume on different wavelengths, a small the antenna tra\'elling to the detector small aerial will reduce it. Slightly switch might be provided to change the tube, or energy being transferred bet ween greater volume may be had with con­ number of turns, as foJlows:-short tubes of a radio frequency amplifier, or nection "B," however, so that nlany wayes 5, medium waves 10 and long still again the audio energy passing be­ listeners prefer it e\'en though it waves 15 turns. KSD and stations of tween the audio stages-it is through does upset the dial readings. I n the case similar wavelength may then be al most coupling that the energy is' passed across. of a set like the neutrodyne, the three doubled in volume, with the average set. To ha\'e coupling, there must be two dials do not read the same, but the first But for the shorter waves, the number of associated circuits carrying alternating one is lower than the other two. turns must be reduced because of the current. One circuit may consist largely It is of great adva ntage to have a absorption effect of so large a primary of ind uctance (coil) and the other variable coupling scheme to adapt the coil. largefy of capacity (condenser) or the set to different aerials. With a long Antenna Wavelength coupling may e\'en exist because of a aerial, only 5 to 10 turns are needed in resistance which is common to both of coil P, but ,dth a very small aerial, as THE aerial system has a "natural'· the circuits. The sort of coupling with many as 15 or 20 may be used. The wavelength of its own, which must be which we must deal almost exclusively is dotted line in " A" shows where the fila­ reckoned with. Users of tuned R. F. or that due to associated ind uctances or ment circuit is grounded, a measure even regenerati\'e receivers with aerials coils. And inasmuch as the coupled coils ordinarily desirable because of its I!:ood having ery long lead-ins ha\'e found wound on iron COres which form the effect upon inductive noises and ~pon certain " dead spots" on the dial. These commercial audio transformer are not ha !ld capacity. are ca used by absorption where attempt to be adjusted, Our discussion \vill be is made to tune the set to the natural of confined to radio frequency transformers. the antenna. This natural ought to be less than the shortest broadcast wave­ R. F. Coupling length received, in order that it may not ET u.s first talk about the coupling interfere seriously with short wave L between the aeIial system and the reception. To smooth out such a dead radio receiving set. In Fig. 1 two methods spot ca used by a lengthy aerial system. whereby this coupling is accomplished either reduce the aerial's capacity or are illustrated. The type of "A" is per­ use a series condenser of .00025 or .0005 haps mOre commOn and it possesses mfds. capacity. The simplest method of several distinct advantages. In the first . educing the capacity of the antenna, if place, the separation between the primary it is too long, is to shorten it. Simply P and the secondary S may be made r shortening it, hO\\'e\'er, does only half , fairly great, and the capacity effe€t of I the job. The greatest impro\'ement the ael ial upon the secondary thereby ---1 comes by increasing its altitude. An minimized. In other words, ~ receiYer so antenna of 60 or 70 feet, raised 20 feet coupled to the aerial will tune almost the A above a roof, is far superior for sensitiv­ same on any aeriaI,-large or small. ity to a 150 foot aerial only fi .... e feet above In "B" another popular scheme is the roof. ~ot only does the passing: shown. Here there is really a trans­ radio wave induce more voltage in the former as in " A" with two diEtinct wind­ wires because of their greater height, but ings, but a portion of the secondary acts Fig. l-The aerial is coupled to the set by the antenna's natural wavelength is as the primary also. Here the coupling is a "coupling coil." This may be a separate reduced at the same time. very much closer than in " A" for the winding as at " A " or a portion of the So much for antenna coupling. \Ve secondary as at " B," The f ormer method same number of turns included. Its dis­ is better in most cases. The aerial's natural now come to a more "ticklish" coupler­ advantage lies in the great effect of the wavelength must be kept low if you wish that which transfers energy from one aerial's capacity upon the broadness of good short-wave as well as long-wave re- R , F. amplifier tube to another one, or the secondary tuning condem:er. A ception. to the detector, (Turn the page) 14 RADIO AGE/or July, 1925 The Afagazine of the Hour _

Perhaps the easiest method of adopt­ ing the variable primary is to install a number of switch points and a switc.1 knob and lever on the panel, where it i", readily accessible from the R. F. tl'an .. - former in the set. This, however, require;; long connecting leads and is unsightly in view of modem receiver construction. A superior method is indicated in Fig. 3. At "A" the coupler itself is pictured, " G" and " F " being the secondary terminals. The smaller winding is the primary and it consists of approximately 15 tu·ms. With a crystal detector, it may be advisable to go as high as 20 turns, although no more than this are needed if the R. F. amplifier tubes are good ones. For the average set used chiefly for c local reception, the switch may have D three taps and the entire primary have only twelve turns in all. A tap is taken PJ~, l at the 7th tum, at the 9th and at the 12th.. In sets using two stages of radio, Fig. 2-How radio frequency tubes are coupled to each other. At "C" is the universally the primary may be smaller, even for OX papular "fixed primary" ty pe. This, however, is efficient only over a moderate wave work, some primary coils working well band. Varyin~ the coupling from about 5 to 12 /UrnS, as at "B." gives better results with a total of ten turns, tapped at the on all wavelengths. 5th and 8th and 10th. The number of turns in the primary must really be In Fig. 2, " C," is shown such a coupler amplifier and detector in the case of a worked out by the individual set opera­ in circuit form. The secondary, of course, single step amplifier. By this method, tor to fit his own conditions. is of the proper size to cover the broad­ the R. F. coupling is as great as possible cast band in conjunction with the variable without causing oscillations and the Back-Panel condenser that tunes it. The primary is volume as well as the selectivity are very as large as possible, but not so large that much greater. H E switch points are laid out on a it passes sufficient energy back to the In "0," Fig. 2, is shown the variable Tsmall piece of panel material, about grid to cause oscillation of the tube. In primary coupler. Here a tap switch is 2 inches square. The switch lever may practise, such an ideal transformer is out connected to change the coupling for be of the regular style or be cut from of the question, for it is perfectly efficient long and short waves. Such a plan is of spring brass or phosphor bronze. I t is for only one wavelength or a very narrow most value in sets having only one stage soldered to a ~-inch set collar. Good band of wavelengths. of tuned radio frequency and a detector, contact to the· lever may be made by The average tuned R. F. transformer is either crystal or tube. \Vith the average using a long set screw and attaching a of this type and is so constructed that its coupling coil, a fixed primary of about nut to it for holding the end of a short primary does not feed back e nough 6 to 8 turns is adopted. Many tuned R. F. piece of flexible wire. This forms the energy to cause oscillation on the shorter reflex sets are made up in' this manner. plate conn.ection II P of the transformer. wavelengths. For this reason, it is not If they are good for long waves, oscilla­ The taps are laid out and so connected quite as efficient as it might be on longer tions prevent good reception on short that a left-to-right movement of the waves. This peculiarity accounts for the waves, and if excellent on short waves, panel knob brings an increase in coupling, difficulty many tuned R. F. receivers the long wave stations come in poorly, The set collar is attached to a length of experience in getting volume from long although with no trace of oscillation. bakelite or brass rod, U-inch diameter, wave stations like KYW, KSD and the which passes through a U-inch hole in like, whereas stations of much less power the sub-panel and also in the main on the shorter waves can be received with panel. The assembly is given at "'C" enormous volume, by comparison. and at "B" the front panel is shown. Three small white dots indicate the posi­ Variable Coupling tion of the switch arm. These are made F COURSE, the obvious method for by filling with white .vax crayon small O getting around this inequality of depressions made with the twist drill. wavelength is to change the coupling, In case there is special interest in DX making it greater On longer wavelengths. reception, more taps are taken, thus giv­ Shall this changing be accomplished by ing a mOre gradual change in coupling. a moving coil whose angular relationship The best way to determine how the pri­ can be altered-like a ticklercoil? Or shall mary should be wound is to make up an we have a permanently set winding, witll experimental primary coil of about 20 its number of turns controllable by a tap turns, with a tap at every second turn. slVitch? The first method is better from The taps are merely bared places in the the standpoint of uniformity and gradual wire, twisted into loops. A spring clip movement, but it has a big d isadvantage. is then used to connect to the taps in The capacity coupling is changed too lieu of the switch arm and points. much and causes upsets in the secondary In most cases: the final result will be a dial settings. Besides, there are too c coil of about twelve turns, with taps many turns on the coil for short wave­ at the 5th, 7th, 8th, 9th, 10th and 12th lengths and the plate circuit is tuned so turns, Or about six taps in all, The high that oscillation commences. adjustments should be tested with good Hence th.e better pla n is to provide a " B" batteries of at least 90 and prefer­ tap switch for cutting in or out the prim­ Fig. J-Details of a variable coupler. ably a little higher voltage, with good ary turns. It is astonishing what an im­ Primary and secondary are fairly well sep­ arated, to avoid capacitative coupling. A R. F. amplifier tubes and the coupling mense difference in signal volume may sub-panel .tap switch permits the use of any coils properly in place with about 1-4 be had with such a device, with variable desired number of turns in the primary. inch separation between the primary coupling for the last stage of the radio White dots 0'1 the panel show where the and secondarv. frequency amplifier, or between the R. F. lever is to be set. ( Turn to page 50) RADIO AGEJor July, 1925 Tile Jlagazine oj tile HOltr 15

HE receiving the input circuit. Tsystem to be Big S tep Toward Efficiency But two stages of described in this in Super-Heterodyne Design intermediate fre­ paper is the result of A quency amplifica­ a very considerable tion were used, for amount of research due to the careful and experiment put design of the trans­ forth in an endeavor A SIX TUBE formers employed, it to produce a super­ was found possible heterodyne that to realize as much would give equal or "SUPER-AUTODYNE" amplification with better results than • two stages as had could be obtained previously been with any existing realized with three type, yet which RECEIVER stages. In each cir­ would employ a cuit, efficiency had ·maximum of six been increased as tubes, for this num­ The Super-Het Reduced to Six Tubes, Yet Giving much as possible, ber must certainly Results More Efficient .Than Seven and Eight a nd the fact that be considered the with but seven tubes maximum allowable receivers of this type limit henceforth, if By McMURDO SILVER give a fairly consis­ the word "efficien- tent range of two to ·cy" be used in con­ three thousand nection with this loud-speaker miles, system of reception. even under present In the past, there _. weather conditions, has been no ques­ is probably the best tion in the mind of indication that this even the most un­ latter method of at­ informed fan but tacking the problem that the super-het­ is the most logical erodyne was the one. ideal radio receiver, A Practical and the ultimate de­ Combination sire of every enthu­ siast has been to be HE next step the proud owner- of T was obviously to a . set containing com bin e the de­ many more brightly tector and oscillator lit tubes than any functions in one other set in his com­ tube. The difficulty munity. Yet this Fig. 1. The compleud rupe, -

ordinarily high amplification over a 10,000 cycle band, with a sharp cutoff either side. The amplifier, employing two of these transformers, together with a sharply tuned filter which is provided with a laboratory adjusted tuning ca, pacity, CS, gives tremendous amplifica­ tion, for it also employs controlled re­ generation, adjustable by means of R3. More Stag,es Unnecessary HILE mOre than two stages ml'ght W be employed, two will go down to the best noise level, so that mOre are unnecessary. Further, there is a decided drop in amplification in adding more stages, which will react upon the pre­ ceding two, so that three stages give, only slightly better results than two. Fig. 2. I ntenor view oj the super-aulOdyne. The instrument desLgnations will be This should really be written "slightly fcund in the tex/. The sockets, Jrom left to right, are: Vl, autodyne; V2, 1st R. F.; more noise," for two stages give more VJ, 2nd R. F.; V4, 2nd De/.; V5, 1st A. F.: V6, 2nd A. F. ; Socket shelves may also than enough gain. be procured for UV199 or C299 tubes. Before going into a description o f a recei\'er designed along the lines out­ for sensitivity- the regenerative detec­ these coils, CX, CX and Cl, which is lined, it might be well to justify the use tor and separate oscillator. This auto­ made variable for the purpose of tuning of the name "super-autodyne." "Hetero­ dyne circuit, in actual tests, appears the oscillator circuit. As previously dyne" is generally considered to refer to give a much greater gain than any of explained, this energy cannot get into to a source of external power-a separate the frequency-changing circuits previous­ the loop circuit, so radiation is confined detector and oscillator tube. "Auto­ ly utilized, and, at the sa,me time, is far to what may be experienced from the dyne" refers commonly to a tube per­ simpler to build and operate than any oscillator coil system itself-a negligible forming the functions of rectification <>f its predecessors. amount. By means of this circuit, which and oscillation simultaneously, so it was is surprisingly efficient when it is con­ The Circuit considered logical to call the six tube re­ sidered that One tube delivers a stronger ceiver a "super-autodyne"-and it cer­ HE actual first tube circui:: is shown signal than t\\·o tu bes in the conventional tainly deserves the appellation, "super," T in Figure 4. The coils L2, L3 are circuit, and is consequently much more for the results obtainable are surprising. theoretically eq ual, as are the condensers sensitive, it is possible to eliminate one Below is a log, representing One hour's ex, CX. Actually, they cannot be tube from the receiver, and still obtain work by an operator unfamiliar with the made fixed and equal, so CX, CX are better results than with two. system. The set was located 600 feet made adjustable, to obtain substantially The intermediate amplifier is the only from WGN, one-half mile from KYW, a condition of equality. These units other unusual feature of the receiver. and WMAQ, and many other Chicago make up a bridge circuit, shown by the It employs but two stages and is on the locals were also operating. All stations heavy lines. Since L2 equals L3, the order of those described by the writer were heard on the loud-speaker. potential across them is equal, so that in RADIO AGE for illarch, 1925. It WCEE 19 48.:; B KS"CO 67.:; 78 L WTAS 23 61 IS WCRD 29 23 L it is also equal between points 3 and -l, differs, however, in that it employs KDKA 23.s 65 S WHAZ 33 30 L and 5 and 6. Likewise, the potential special laboratory charted transformers WGR 31 71 ::I WLW 4ll oU L WDAF 31.S 21 L WTAO SO .5 64 L across C X and CX is equal. Since the which are a compromise between the WTAM 36 31 L KFI 49.S 63 L KSID 36,5 33.S L KSUl 45 3:1 L potential across 3 and 6 is the same for extreme selectivity of properly designed wcco 40.5 39 L WQJ so 45 L wos +1.5 45 L WTAY 16 37 B both inductance and capacity, then air-core coils, and the great stability WCAP :;0 63 L WBeN 18 43 B points 4, 5 and the joint between ex, CX and amplification of good iron core trans­ WSL'I 53 58 L W JJD 22.5 61 S WEAF 55.S 5.~ L WLS 28 85 ~ are at equal potential, and are also formers. But two core laminations are wex GO.S 67 L WIMP 52 66 L WOA W 63 70 L WEBB 3:1 95 S theoretically at zero potential, since used in each transformer, of 7 mill WGN 32 25 L these points are neutral with respect silicon steel, one in the shape of an " F" The station separation was very pleas­ to 3 and 6. Then, circuit Bl, e2, B2, and one an "L." The air gap formed, ing on some of the unlisted lower wave may be connected at these neutral points, . together with other recent ly developed stations, due to the use of the straight-· with substantially no r eaction on the features of the design, permits t he realiza­ line-wavelength conde nsers. A compari­ frequency of the bridge circuit. Further, tion of almost a n ideal Cu rve-extra- son with a standard five-tube neu tro- as these points are neutral with respect to 3 and 6, no energy in the bridge cir­ cuit can get into B I, C2, 132, since there is no potential difference across t hese points of the bridge. Therefore, the frequency adjustment of the bridge cir­ cuit cannot react upon that of the Bl, e2, B2, circuit, and vice versa. Since the signal is fed from the loop and its tuning condenser to the oscillator, it will divide equally across the bridge arms. If a tube detector is connect ed across one capacity ex, the drop in potential may be used to cause rectifica­ tion. It would appear that some of the signal voltage is lost by this method, but actually it is not. It is, as a matter of fact, considerably reinforced when the new component is finally fed to the amplifier, probably due to regenerative amplification. The coil Ll, coupled to • L2, L3, causes the brirlJ.'{p. circuit to Fig. 3. Bottom view of the socket shelf assembly. Notice how all parts are rigidly oscillate at a frequency determined by f astened in place-an important f eature for portable receivers. RA.DIO AGE for July, 1925 The }.!Iagazine of the IIoltr 17 dyne on a 100 foot antenna was unfavor­ middle. A small speaker is to be r eC O I~l.:. The act ual assembly of the receiver able to the neutrodyne both on the count mended for its small size and genera l is extremely simple, providing a standard of selectivity as well as sensiti\'ity and portability , and it certainly ta lks up socket gang a nd a drilled panel a re use,!. volume. A standard super (see :'.Iarch very much" bigger" t han it looks. If this is not clone, it will be necessary RADIO AGE) failed to produce any The material required t u uuil.! this lO d rill up a suu-Lase and panel to take better results, as d id another eight-tube recei ved is lister! below, wit h the designa­ the inst ruments. The panel may be set employing air-core transformers. tion letters used. in t he diagrams and cuts grained if desired by rubbi ng wi t h fine While the outfit will deli ver about the following the quantity of each item sandpaper and o il until all traces of the same energy with either dry cell or stor­ required. \\'hile it is entirely permissible original fi nish has bee n removed . In­ age battery tubes, the llry cell tubes to substitute any other standard parts dicating ma rks for t he condensers can will generall y be sadly over-loaded, and for those listed, it is strongly reCOnl­ be scratched with a scriber and fille d it is, therefore, suggested t hat UV-201-A mendell that the p~ rt s s lJecified I.e used with white. tubes be used throughout, although for se,'eral reasons. The actual space H Figures 2 and 3 a re carefully studied, even so, it is IJOssible to overload the availahle is such that parts of la rger no difficulty should be encountered in sixth tube. This will be appreciated or different dimensions could not be moun ting all the parts, following the when it is realized that in Chicago it is substituted in some instances, and in t he designa tions shown, which are also possible to get "olume sufficient for case of the RF Transformers, and 5L \V gi\'en in t he parts list. As the parts dancing from the \Vest Coast stations condenser, it would be inadvisahle t o are mount ed, the wiring may be sta rtecl on five tubes using only a small loop, substitute, since t he results of the receiver and put in progressively o n the base u nder favorable conditions. depend in a large measure upon the use and ranel, then the two joine,i together The portability of the set may be of the types recommended. a nd the final connections made. It is realized even with storage battery tubes ~ ~J ·)?;:;ki~rdi~ ~ ~~:::~~ey~ pre'e r ~ b1 Y necessary to use a well-tinned soldering by means of special leads if a car is 1 R-t 6 ob m r be().1 .b t 1 it.' 240 ohm pot entio meler iron. with rosin core solder and some handy. These leads permit connection 3 DL. B 2. I-\,1 inlUlated toP billdin: po,ts 1 J 2 101 jack (1- prin,,) non-corrosi \'e paste. The bat tery leads to the car battery through the dash­ I J 1 l Ol -'\' hC'\;: (> JO. fl nnC) are brough t ou t t hrough a color cable, 1 C-.'i. 2 11 6lter 'W i tb m at d ied tun iDS' c:l. PItot' i.ty board light socket for the " A" supply. 2 210. 2 10 cb artM intcrmt:'di.J.t& (T1U1slormerw coded in accordance wi t h the A. 1\1. E. S . If this is not possible, it is suggested t L t . 1.2. La. eouplin: uRit 16 nnl' ~ oc" et Abelt (5:lf~2'01 ~ '-\. ~O . Sr37-1 ~9) code, thus obviat ing binding PU l:i ts and that the necessary dry ba tteries be car­ 2 TI. T 2. 3,Ya: l or 2.1 tran... (orme-n 2 C 7. C8 .5 condon.. en providing permanently a ttached con­ ried in an old hand satchel, or even a 2 CJ....C4 .OOOZS eonde Q1'ent w ith cliPd 2 C g. C IO .002 C OrtdcfL.. e,.,. necting leads at One operation. lunch box or tool kit. Then conneC­ t C6 .0075 eonltellSen 2 ex. ex . oooo~;; cOn I. .... ,. After the receiver has been wired, the tions can be made quickly with the • RI .5 Me~ le 1.k. color cable used for the battery leads, t R2 2 m eg lol1 k necessary batteries should he connected 1 91 Xo. 3 i:l.rk !'w it ch (S . P. D . T , and the receiver set up in a few sec­ 11>28630 . ,,·itch (s. P . S . T .l to it, the rheostat just turned on, and 1 t.. o. 701 enlor eable (5 1es.< 'Ut the whole set can readily be managed by J sirle-cuttiut: nliers an unhalanced bridge circuit. \Vith One man. 1 SCrow d ri\'er one condenser CX set all in, turn the Ins pectin g the Se t other C X slowly out, rotating C2, mean­ Portable or Permanent 5 500:\ as the material has been while. If the plunk does not disappear, HE advantage of this arrangement A procured, each item shoud be care­ reverse the operation, lea\'ing the other T is that the same set serves for camp­ fully examined to see t hat all screws balancing condenser all in to start with. ing or traveling that is used to prodde and nuts are tight, and lugs placed as Once the plunk has heen ba la nced out entertainment at home at other times. shown in the photogra phs, so that t hose for a(l settings of C1 a nd Cl, condensers I t is possible, if the builder prefers, to on the various instruments will point in CX, CX should ne,'er be touched . If have a luggage shop make a carrying the best rlirections for short leads. squealing or clicking is experienced at case so arranged that the receiver is at Socket springs should he bent up to make low settings of Cl. it will he necessary the top, the batteries below, an!l the good contact with tube pins. Condenser to use a smaller grid leak at R 1. This loud speaker in the lower compartment bearings should be adjusted to give the leak will generally vary het ween .25 with them, either at the side or in the desired tension. and .5 megohms.

r

YELLOW I'LACI( ­ R~D TRACE

B, Bz B, B-+4!:J B~~O A + 8~OW N ~ LuE I?~O Fig. 4. The wi r in~ diagram of the new super-autodyne receiver. Hereto]ore to obtain n eutrody ne results on a loop aerial, seven and eight tubes were necessary. But in this receiver only six tubes are needed to achieve the same end. 18 RADIO AGE for July, 1925 The Magazine of the Holtr Vacuum Tubes as

Devices By DR. PETER Some Interesting S idelights on The Repeating Function and I. WOLD "Distorting" Function of Tubes N THESE days all of us have be­ peating electrical variations impressed on give oscillations of an audible frequency. come so well acquainted with V'acuu m the grid generally with amplification and, The repeating action of the tube and I tubes, through actual use or thrQugh at least theoretically, faithfully, or with­ its circuit, with amplification, would the countless articles on radio sets out any distortion. By the second. I refer probably be held to be the more impor­ making use of them, that anything to that property of the tube by which tant property,- for it includes such further might almost seem superfluous. electrical variations on the grid result applications as long distance telephony On the other hand, there may Le some in variations, generally amplified, which and all the actions in radio work men­ who have only recently acquired an are substantially (iifferent. As an ex­ tioned above, eXcel)t those of detection interest in radio, or it may be that the ample of the fi rst, we may take the and modulation. On the other hand, exceedingly versatile device very com­ relaying of telephone messages across its property as a distortion device is the monly but very poorly called a vacuum a transcontinental line in which the more interesting, though not so gen­ tube offers some point of view which greatest p reca utions are taken to make erally understood. may be new to many. the repea ting action as faithful as possi­ Let me remind you for a moment of If you have followed the radio art ble; i. e., t o reduce distortion to a mini­ the essential clements of the standard for some time, you have heard of these mum. As an example of the second, vacuum tube. There is a filament tubes being used in a number of dif­ We may t a ke the detection of a radio which may be raised to a high tempera­ ferent ways, as for audio frequency message in which electrical oscillations ture, whereupon it may give off electrons amplification, radio frequency amplifica­ or variations of perhaps a million -those smallest particles of matter or tion, detection, regeneration, reflex re­ cycles-and therefore quite inaudible electricity which we have come to generation, any or all of these occurring -are so distorted or con yerted as to recognize as playing so important a in your receiving sets; and if part in all our affairs. Then your interest carries over to there is a plate kept at a the broadeasting station, you positive potential by the B have heard of oscillation battery. and which therefore generators and modulation. attracts the electrons from All of these terms may the filament, thus giving rise suggest a confusing variety to an electric current to the of uses for the vacuum plate. Finally, there is the tube, but it may simplify grid placed between the two. matters if it is pointed out When the grid is made more that this tube has two positive, a larger current functions only, which are flows to the plate and separa te and dist inct, and through its circuit, and when the various uses mentioned it becomes more negative come under the one or the a smaller current flows. It other. These two functions is possible thus to control a may be sl,oken of as the current by changing the repeating function and as the potential of the grid; and the distorting function. The two important point is that the are present in every tube in energy for exercising this an amount depending on the control may be very much design of the tube; i. e., the less than the energy of the relative sizes and spacing of controlled current. It is for the elements in the tuhe. this reason that the device By the way in which the acts as an amplifier. tube is opera ted, and by the circuit with which it is asso­ Getting Min imum Dis- ciated, one of these functions tortio n may be emphasized. F, starting with a small What It All Means I current t o the plate, you draw a line showing how this y the first of these func­ FIg. I . A tYPical grid ,hartlCleftstlc ,harl jur 199 type (J /IOlt) current changes as the poten­ B tions. I mean that of re- tllbes with plate voltages of 45-80 and 90 volts. tial of the (Turn to page 60) RADIO AGEfor July, 1925 The .Magazine of the I!oltr 19 The Correct ~ ~ B" Battery for your Portable Success Liberal or Failure Supply of the at Start Vacation Will Radio Depends Insure on the Success Condition of Your "B" Battery By EdgarH. Outfit Felix

HE B battery is the power plant of Economical upkeep and long service with­ any B battery, in milli-ampere hours, is your radio set and its failure means out renewal of batteries must gi ve way to proporticnal to the quantity of active T that the portable is temporarily the utmost portability. For this reason, c hemicals within each cell. Only a cer­ useless. At home, batteries are not the smallest and lightest B vattery ob­ tain amount of each essential chemical difficult to replace from the liberally t ainable must be used, because the larger can be placed in a given space. Conse­ stocked shelves of a nearby radio store, sizes are altogether too bulky and heavy quently, the size of the battery places but in the wild and woolly haunts where to be carried for any great distance. definite limitations upon the output many of us seek rest from the rigors of To meet these requirements, B battery which may he expeated from it. The city life, B batteries are as rare as the manufacturers have placed tiny ra dio smaller the battery, the shorter its life proverbial dinosaur. power plants on the market. These con­ a nd its curren t output. B battery costs, Hence, give this important element of sist of an assemblage of very small cells, per hour of operation, increase rapidly your Summer radio set all of the consider­ sealed in a small container. They repre­ as the size of the battery becomes smaller. ation which it deserves. Take the same sent the greatest possible amount of Before starting on your trip with a precautions that you would before sta rt­ electrical energy which can be crowded portable set, he certain that you have a ing on a motor trip across a hundred into so small a space. But the output of B battery power supply which will last mile desert- make over the period of sure that your fuel your trip. Do not supply will be suffl­ expect long life from cient to carry you to tiny batteries called the next service sta­ upon to deliver tion, with an ample heavy CUrren ts for margin to spare. multi-tube sets. There are two The smallest B bat­ kinds of service for tery, shown at the which porta ble sets left of the illustra­ are designed and tion on this page, your B bat t e r i e s has a ll the capacity should be selected which can be incor­ with these in mind. porated in a battery First, there is the of that size. It has pack set, which can a volume of 17.5 be carried on a hike, c ubic inches. like other portable The next larger camp equipment ; size, at the center, and second, there is has a cubic content the self-contained of 28.6 cubic inches, semi-portable, for or 63 % larger. The temporary installa­ tall, slim battery at tion during vacation the right is 50.3 time, in camp or cubic inches or bungalow. 186% larger than .\ the smallest battery . The Pack Set Obyiously, there is N THE pack set, considerable advan­ I everything must This layout shows the various sizes of "B" batteries. It is advisable to spend tage hoth in milli­ be sacrificed to se­ liberally in equipping a portable set with "B" batteries, for a stingy Investment at the ampere hour capaci­ Cure light weight. start usually results in woe later on. ty and economy in 20 RADIO AGE for July, 1925 The Magazine of the Hottr.

The illustration shows five sizes of Storag~ "AU Battery B batteries in such a manner that you will Size be able to identify them when you pur­ No. r~ Total Recommended Voltage of of I Rated chase B batteries for your portable sets. of Tubes Tubes Ampere Amp. Hours Days The smaller sizes. shown at the front of Tub< 5 in Set (.ee foot-note) Drain at 1 Amp. between Drain Charging. the illustration, should be used only when 65 22 portability requires their selection. Their 1 UV-200 1 ~ r output in milli-ampere hours increases 47 16 more than in proportion to their increase 2 UV-201A U 47 33 in size. Considering that the largest of 80 22 these portable units-the tall battery 1 UV-200 I ,." ----or at the right-has less than 25 % of ·the 2 1 UV-201A 65 17 electrical capacity of the large battery tiS 29 shown at the left in the back, the greater 3 U V-201A ~'.. - .. - 47 22 lasting qualities of the larger batteries ---- become obvious. 95 21 The large size, back of the small bat­ 3 1 UV- 200 1 ;"5 5-Volt 2 UV-201A tiS 14 teries at the left. has considerably greater Tubes - lasting quality than the next preceding 65 22 , . . 4 UV-201A 1 size. It is the middle ground between C-300 and UV-200 - ~7 16 the utmost economy, as embodied in the are interchange- 115 22 extra large size, and the uneconomical able 4 1 UV-200 l U ---or--- - 3 UV-201A tiO 15 smaller sizes. There are several makes C-301A, DV-2 and of semi-portable sets equipped with ~O 22 battery compartments which will house UV-201A are in- 5 UV-201A 1",. -----

Here LS An Outfit \Vhose Cost Can Be Kept Well Below $[30 by the Careful

Home­ The: set described b y Mr. Haynes, wired a n d ready Builder to v,.o into the: c

A Popular Receiver That \Ylill Give Dependable Loud Speaker Results in SUfnmer Up to 1,000 j\1 iles

OR the past three years, portable article has been thought out with com­ the hatteries still have lot s of pt:p. radio sets have been built in great plete portability, low cost a nd good per­ The "What will it do' " club is prob­ F profusion-in \Vinter con,·ersat ions. formance as the primary considerations. ably becoming quite anxious by now, When· the good old Summer time rolls The set is completely self-con tained. and it is fair that they be answered. around, howe"er, rarely does a radio Although the loop is built in the case First, claims of the "coast-to-coast -on­ set accompany Dad in his jaunt to the co,'er, it will be found as efficient as the the-Ioud-speaker-in-daylight" type are Maine woods or the family on their ordinary loop of approximately the same ruled out. T he set will give dependable annual flivver trip. dimensions. The cost of the outfit Can l oud speaker results in the Summer time This lack of enthusiasm in t he past be kept below S130.00 for the complete on stations up to a d ist ance of 1000 can be attributed to a number of rea l units and this price includes all the neces­ miles. T his means results which you reasons. There were only two or three sary tubes and batteries. E,'en this ca n enjoy and, if you are listening to broadcasting stations with sufficient comparatively low price can be cut con­ music, dance to it without ha ving to power to make reception pleasant through siderably by judicious shopping. imagine half of the tune. On nights static disturbances a year ago, many that are favorable to reception, yo u Sa me Constants portable sets were "portable" only be­ ca n make a very comfortable and cause the case was leather, and sometimes F YOU substitute parts other than thorough tour of the cou ntry \'ia the the batteries were enclosed, and fina'l1 y , I those shown in the material list, be loud speaker. the cost of a good portable receiver was sure that the new parts have constants :-'Iost of the tests run on this set were al most prohibitive for t he a,'erage exactly si milar "'ith those specifie

The socket strip for the simplified portable super-heterodyne, shOWi ng one filament lead and method of binding lugs for other filament lead. 22 RADIO AGE/or July, 1925 The Magazine of the IIour case may be purchased from one of a place a lug under each nut number of firms advertising them. Ow­ which locks hoth a socket ing to the chance for confusion, it is best and condenser in place. to cut the leads only as needed and to H ere i. the This is done at points AlO, completed set All, and Al2. mark the drawing as they are used. In ready for ac­ this way a double check is kept on the tion, with a Before attaching the new type of .00025G condenser in place, work as you go along. loud-spcaker. This istrulya put a 6-32x%'" machine Assembling and Wiring the Set portable out­ screW through the conden­ fit, and tests If the instructions given are followed in the crowd­ ser at H5. Lead No. 35 is ed Chicago now cut to length and at­ carefully, particularly the order in which area showed the leads are connected, the average it cut> thru tached under the nut at L locals up to and the other end secured fan should he ahle to complete the wiring 1.000 miles of the set in three hours or less. The on the speak­ at Lt, the Grid of the first er. That's detector tube. time required to complete the ba1ance good for sum­ of the work depends on the cabinet. mer, isn't it? Lead No. 1 is attached at Note the loop If you have purchased one ready-made, wound in the the end of the 5· section to the set should he operating ahout four cover. the first grid condenser at hours after you start work on it. H5. The only two leads which must he Leads are now partially soldered in the set itself run to the jacks completed to each of the and, owing to their posi­ by-pass condensers on the tion, are easily attached. socket strip. Lead No. 25 is soldered to the .e06 con­ Material List denser at G4. -Solder one 1 S"][ICM":a:3/IG" B!lkelite P&oel end of lead No. 22 to the I I~ ·x16 X "z3/1C' B~k.li '" Strip 1 7"][lG}i'''z3/1C· YoncczBaseboud other .006 condenser at D6. 2 .0005 odd. v ~,ub l e CoodcQ,;eMi One end of lead No. 26 is 1 Set I. F. Traru..!or:z:nera 1 OaciI.btor CouvLor soldered to the .005 con­ I 3 Pbt. Cood.... "" &; Knob denser at C4. At L2 of the 8 U"199 Sockeu 2 Audio Tr.ms!ormcn: .002 condenser solder lead 1. 4000bmPotentlOlncter No. 23 and attach the other 1 FilAment Switel, 2 lArks end to the plate of the J Turnit COD.dens"r • second detector tu be, L. :2 .000, m fd.. CondcD5e rs 1 .005 mfd. Co nd~Q.... er The lugs which were left at points AlO, 1 .002 tnfd. Cobdon:.er All and Al2 are now turned until they 2 .000!!5G mid. Cood.,.,.- p ass under the nuts at A6, A8 and A13. "'"1 3 Mecobm O dd Leak The negative filament lead is later 1 5 l\,Iccobm Grid Lenk J 10 ll L ..... more easily if it is not mounted. 6-32x right angles to the socket strip, bend 4 t...DCths Rooin Cor. Solder the tips to right angles, insert and solder 18 BrASS W .,"~ be ' 8 for 6-32 l\1a.cbme Screw.'! % " machine SCrews are used to secure 12 n" II ...... Wood Scre .... the instruments to the board. the hus bar and finally bend the com­ 5 Rubher Bu,diM P osts 4 Ra.kelite Loop Bupuort Stl'1P3 pleted leads as close to the sockets as 100 ft. Stn.ndc(i Loop "'·iro The Socket Strip 1 Portable Cahine t possible. No identifying letters have 1 Loud Speal.or THE assembly a nd partial wiring of been placed on the diagram to show the Bakelite was chosen for the first two the socket strip should now be under­ position of these leads but as the sockets panels because of its mechanical strength. taken. Where a bolt is used to attach a re marked, you should have no difficulty Veneer was chosen for the baseboard only t he socket to the strip, use 6-3Zx U · in doing the joh correctly. These last hecause of its cheapness a nd light weight. machine screws. ' \There a holt attaches operations complete for a moment the If,. however, you wish to use hard rubber both a socket and a condenser to t he work on the socket strip and we shall or bakelite at this point, there are no strip, use 6-32x L ~ " machine screws turn to the wiring of the oscillator reasons why you shouldn't. and cut off the extra length. Be sure to coupler.

I~ ~ .. o\o t:. • .! "'D I ~ I\! .6.VCHO l."'.! -.U010 .... t~ut."(."( ,P,lqut.",t.."'t r~,"QUt."'c, , ..t.q\J\.",c."1

The schematic wiring diagram of Mr. Hayn.es' receiver. By f ollowing this layout lh~ bzginner should have no trouble in building the portable super. RADIO AGE for jilly, 1925 The Magazine of the lIour 23

The oscillator coupler consists of three is meant respectively. Attach one end Attach the lug at the end of the 10" separate windings: the pickup coil, the of lead :No. 32 to the inside terminal of section of lead N o. 5 to the outside t er. grid coil and the plate coil. In referring the pickup section at A7. Lead No.3 minal of the plate section at Cl. Fasten to the "inside" 'or "outside" connections is attached to the outside terminal a t lead 11 Ki th the tap a t the end of the to a section of the coil, the tap nearest 113. Lead No. 19 is attached at J to the 10 )4" sect ion to t he inside termina I of the center or furthest from the center inside terminal of the plate section. the grid coil a t El. The lug at the end

LEt-lCtlHS Of UA05 IN ~E.\ , ~==~==~~-=~~.~~~~==~~==~--~~=-=--=~~======~ -,; .,.' ~ " . - --_. -.-- .-.j 1 ~ . 4~ ' i U ' _ 01 ) ~~~==~==~======~======-====.====~\ 1 14" '1 4 ~~" ==='~=- =-~l~'=" ~~. ~~=,,=,,=-=-=-======~--= ~

_4 - - -10. ------~ ~~_=· _~_ ._=_ 1\~'·.. = - ~~~~==~=--n~~--~~~~·.--~~~~.~- ;=. -==- ~lt ·~.~i·-=~4 . ~~~==~======~-====~=-==~======~======~======~--~~==~=-~~ 1~ ' ~ J. - It. --- • r-L===-" =' ~'-\4~i~' -_=-·-·-· -_-_-_-,=_ =,,=_~· ·~--==~~======~~~~--=---~--===-~J

_.. -l of t he 7 U U section of lead No. 13 to the outside terminal of the grid coil at K . This completes for the moment, the wiring on the oscillator coupler. The battery cable should be prepared for use by cutting away the covering for a distance of 1.+ ". Whipping the cover­ ing at this point will prevent fraying of the covering from ta king place. Use fairly hea vy threa d for this purpose. Measure the length of the battery leads from t he point that t he covering is cut. The C ba ttery negative is lead No. 10. Filament negative, B battery negative is lead No. 14. II battery positive de­ tector is lead No. 39. Lead No. 21 is the ~L--~ f =Y u ~ "- .!>i' -!~. l. ',, -"l .t'-- .. ,-=4));r filament positive. B ' llattery positive to ~ . ~ u amplifier is lea,1 No. 20. I ~"------.I \0 .) ~ ~ J,.. . - 't'- -' =:i .. ~~======~ Lettering used to designate battery .-. - - --~.- - -_. -.- --J I. .. .) ~ . -. -. J ~, r:.- l.'--- J circuits ale based on the following list: n ~;"--.b' _ _ _ -.l l- A minus n minus ...... Letter A " 1- . t·--:.l t~ @ , ~ A plus ...... _...... Letter B r..~- .- --4"; - ·- . . - ·4 'l l ~. I.···t • .' .. ,¥ II plus detector ...... _ ...... Letter C 14 ~ @ H ~==~=-=:~ '1:...-. --4-f ---- . .. ~ 1: t.~ II plus amplifier...... Letter D ..

Suppose a receiving station in Chicago is r eceiving both from New York and Lo. Angeles. A pa tch of r adio fog m ight appea r between New Yorl

VER l'ONE who has a radio receivi1lg that some t hings in space will sto p, o r possible to "\\'ork radio communicatio n E set has lIu l the atmospheric Il uisance reflect, or perhaps absorb the travelling over much grea ter distances at night than called " ,slatic." It COmeS in, especially radio wa ,\'es, just as some other things in in the dayt ime. This may be explained during the warm months, and i nterferes space stop or absorb or reflect light by the effect of the sun upon the air, with d ear recePtion. ,1 particularly waves, or sound wa,"es. \Ve must not which causes ionization of it, and is most pleasing musical number may be on, but expect radio waves to tra, 'el out from a acti"e in the daytime and pract ically Ihat makes Il0 differmce to Old Mall transmitt ing station, o,'er some enor­ absent at night. T he sun seems to be Static. mous distance to a recei"ing sta tion, responsible wi thout question, in view of So many inquiries have been recei]'ed without encountering some obstacles the fact that ,"ery erratic results in long at the Gelleral Electric stat-ion, WG Y, at somewhere in its path. distance reception a re always noticed Schenectady, that .1. F. r an Dyck, a radio at sunrise anll sunset. engineer, has prepared the followi ll g How Radio Pierces Walls Wave Power Varie s paper, explaining sOllie things that are UBSTANCES which are obstruc­ known about static and what is being S tions to light or sounlt wa,'es-are not JTITH t he preceding statements in dO ll e to get rid of it. Alr. 1"all Dyck's necessarily such to radio wa ves. For r l mind, it should be clear t hat when explanation f ollows: example, we kno\\' that radio wa ves pass o ne is recei" ing over long distances­ through the \\'alls of a house with only several hundreds of miles-it is natural ' N THE letters which WGY has slight 105s. But t here is some substa nce for t he wa,'es to come through strong at received from listeners, certain ques­ in the space Moun,l t he earth which one moment , and t o fade away cO)l sid~ r ­ I tions ha'\'e heen aske(\ by many does have effe ct upon radio waves. This ably the next moment, as so me o bstacle different - inquirers. Some of these substance is not uniformly distributed to radio wa,"es comes between t he trans­ questions involve radio phenome na which through space, but is present here and mi tter and recei \'er. This explains, too, are not completely understood by scien­ there, a nd is continua lly changing loca­ why one transmitting station , of two or tists toda y, and t he answers a nd explana­ tion a nd magnitude, and conseque ntly more which a re being heard, may get! t ions which we shall gh-e should be under­ has very erra tic effects on the passage of weaker, while the others do not. For stood to he the ones which are belie\'ed radio wa ,'es. example, suppose a receiving station in to be nearest t he truth, although they The condition is quite similar to the Chicago is receiving from ~ew York are not subject t o rigid proof. use of a searchlight in a fog, which might and also from Los Angeres. A patch of First, let us consider what radio be varying rapidly in density or location, radio fog might appear bet '\\'een Chicago t ra nsmission is. We know that a radio or bot h, T his radio fog is commonly and ~e w York and wea ke n t he New sending st ation sends out from its an­ "supposed to be made of ionized air ; Y ork signals, ,,-hile the signals from tenna in all directions, a dist urbance of that is, air which by some influence has Los An geles remained unchanged . \\'hen­ electric forces. \Ve cannot see or hear become a part ial cond uctor of electricity. ever in reception o ver a considerahle or otherwise obsen -e with our senses just Of course, this radio fog never sta nds distance, one observes a va ria tion in t he how this disturllance behaves, as we can still and is changing from moment to intensity of t he signals, it is most likely wi th light waves an,1 sound waves. moment u nder the influence of the com­ d ue to so-called " fading," caused by \Ve consider it q uite nat ural that a stone plicated conditions of our a tmosphere, some obstruction t o the traveling waves wall stops the light beam from a search­ and so the ra dio wa ,\'e passing through somewhere between t he two stations, li ght, or t hat a bugle call ca n be heard space surely has a n adventurous journey and not to a ny fault of the transmittin ::{ much farther o'\"er water than through a because it meets elect rically charged station itself. These effects a re much forest, or that under certain air condi­ clouds, patches of ionized air, and per­ more frequent in the Summer than in the tions on a desert, the mirage phenomenon haps other obstacles of which we know \\'inter, presumably because of the great ­ is observed; and to know what to expect nothing. er influence of the sun on t he earth a nd in radio, we need only to remember It is a fact often observed that it is ( TUrn to page ( 0 ) RADIO AGE for July, 1925 What the Broadcasters are Doing 25

Gloria Confesses

•

Gloria Swanson, who since her marriage to a dashing Frenchman is Marchioness Something-or-Other, made her first broadcasting appearance under her new name from WGN, located on the Drake Hotel, Chicago. Seated before the" Mike," she answered sev­ eral exceedingly personal ques­ tions put to her by Announcer Quin A. Ryan of WGN. The questions, by the way, had been sent in by inquisitive listeners who had been notified of the famous .. Radio Inter­ view","with Gloria as the Inter­ viewee, who seemed willing to tell all her deep secrets for her rad:o and movie admirers. 26 RADIO AGEJor July, 1925 What the Broadcasters are Doing What t he B roadcasters are Doing

Portable " P ick-up" Station McNamee of WEAF Chosen for KDKA Best Announcer o TAKE care of the ever-increasing RAHAl\1 l\lci\'AMEE of WEAF T"pick-u p" situation that has con­ o a G was selected as the best all-round fronted Westinghouse station KDKA, Iris Virginia Gruber has the distinction of broad · local announcer by the Radio Voice casting more than any artist In Philadelphia and at E . Pittsburgh, the Westinghouse is the winner of the Radio Cup presented for Technique Committee of New York engineering depa rtment detailed Engi­ "nging the greatest number of time. dunng the University at a meeting held recently, neer Carrol ]. Burnside to construct a concert season from January 1st to May 1st. according to announcement made by portable short wave sending station, the committee. Mcl\' amee nosed out to permit the immediate and practical Brockenshire of W] Z by the small broadca sting of various interesting and "Ford and Glenn " t o margin of four-tenths of a point, the important events, as they take place in Tour u. S. SCOres being 87 .3 for McNamee and their vicinity, despite the fact that 8(;.9 for Brockenshire. ~ORD R USH and Glenn Rowell, location may not permit tele phone wire I t he "Lullaby Boys," whose songs This committee meeting terminated connection with KDKA. a nd bed-time stories during "Lullaby the series of three which were held A one-ton truck chassis was pur­ Hour" and "Ford and Gle nn Time" during the past four months under the chased and suitalJ le house-body built, over \:V LS, the Sea rs-Roeb uck st a tion, direction of R . C . Bordon and A. C. wherein the pick-up apparatus was con­ Chicago, have endea red the m to t he Busse, voice experts of New York Uni­ structed. The req:l irements of this hea rts of kiddies and their parents versi ty, to determine the ideal qualities transmitter were that it be absolutely throughou t the nation, wi ll st a rt on a to be looked for in radio announcers. dependable at all times, in any loca­ transcontinental tour o f t he United The aim of the committee, which is tion, and make use of a low wavelength, States June 2. The WLS favorites will composed of radio editors,. dramatic which is free from inte rference. The broadcast t heir most popula r features critics and members of the faculty equipment must be compact and its over nineteen of the principal radio of New York University, is not to personnel small and upkeep low, to stat ions clear to t he Pacific Coa!'t . standardize the voice and art of broad­ justify its use. The body of the truck The journey from station to station casting, but to point out faults to be is 5 ft. wiele by 9 ft. long and is (; ft. will be made in their new sedans, in avoided and to determine what the high inside, solidly built t o withstand which they wi ll carry complete camping public prefers to hear. the jar of movement of the truck in out fit s. I n many of the 'places t hey Special phonograph records were made motion. All equipment is cllshioned to will live out in t he open with their by l\lr. Borden and Mr. Busse of repre­ minimize the jarring of apparatus. families, who will accompany them. sentative annonncers from the following The transmitter is a quarter-K\V ~t, nine New York stations:- W]Z, WEAF, IIsing 110V from lighting circuit whe re WGBS, \\,HN, W EB], WOR, WAHG, program is being broadcast, a nd a p.;)\ver Wl\ICA, and WBBR. Each announCer transformer in the truck is used to step passed upon his own record and all up to the high voltage required to oper­ t hose entered in the cOntest had been ate the set . Power at this high voltage accepted by the makers as fairly repre­ is passed t hrough a vacuum tube rectifier sentative of their work. using two quarter K W air-cooled recti­ Ten men out of the number considered fier tuhes, which gives single phase full were chosen as the best local announcers. wave rect ification. The output of t he I n addition to l\lc • amee and Broken­ tubes is passed t hrough a brute force shire they are Barnett of WOR, Reed filter of choke coils and condensers, of W]Z, Carlin of \\'EAF, Squires of which delivers 2000 volts DC power to Wi\/CA, Granland of WHN, Haupt 'of the transmitte r, which makes use of the WEAF, Cross of W]Z and l\/org:!n of standard Hartley oscillator circuit with WGBS. Heising modulation. The committee rated the records The equipment used in this portable upon the points which were decided set is capable of wa velengths varymg upon at earlier meetings as those most from 20 to 100 meters, although the desirous for radio announcing. They set wHi ordinarily be operated on about are as follows: (1 ) Average rate of 53 meters- KDKA to pick up its broad­ speaking-175 words a minute. (2) cast and rebroadcast on their standard Pitch of voice--Iow middle range. (3) wavelength of 309 meters. Announcements should be made with Because of a Ii kelihood of broad­ variation of rate, pitch and stress. casting from some downtown section (4) Manner of announcer-formal but of the city, where it would not be prac­ friendly. (5) Distinctness and enun­ tical to operate a regular antenna, a ciation. vertical oscillator type is used. A Above is "Si" Berg, nationally known ukelele A summary of the comment~ made copper pole of three sections, of the artist and songster, who has appeared all over the country before prominent microphones. He is by the committee during the course of telescoping type was constructed, which now appearing consistently from WHT and KYW, the meeting has been arranged by Mr. is folded and stored in the truck when Chicago, having contributed recently to the success of many RADIO AGE programs from Borden and 1\lr. Busse for public dis-­ not in use. the latter station. tribution. RADIO AGEJor July, 1925 What the Broadcasters are Doing 27

THE alluring M iJ. ador n ing Ihe perfume bollle is none olher Ihan Mtte. Rosario Duprez. pro m i ­ nen/ New York fashwn queen. w/w is telling 1M flap­ Radio's p"s and ·gay ma­ trons in the East how to achiet'e pu­ sonality 17)1 means of perfume. N eed­ less to say. she has a large feminine ~ ~ Interview (and mascutlne) lollowing. both for her radio as w.ll as her pulchri­ tudInous attain­ mMls. Lady"

HE Greal and Scoops the T the Near Great Appear Be/ore the. WGBS "Mike" in World! New York To Be I nterv iewed and Revea l How to By MILTON Achieve Success. L IEBERMAN

WOMAN has brought the news­ and I waited until she had finished her t1lem. There was Ruhe Goldberg, Miss paper to the radio world. She has call. Oliver H<>rriman, Jane Cowl, Tony A woven the two togteher and has " I just did a good piece of newspaper Sarg, Victor Depew, the cartoonist, brought shortcomings of one to be val­ work," she told me. "I was just inter­ Willem Van Hoogstratten, conductor of uable features of the combination. "iewing Mrs. Anna Norton, who was the New York philharmonic orchestra, She is Terese Nagel, the "r n ten'iew" chairman of the democratic party during Fay King, several actresf>es, including lady of WGllS, the Gimbel Brothers their national convention, and found l\1iss Blanche Yurka and Miss Mary store, New York City. A newspaper that she is going after a big political job Mellish. The Hamilton brothers, Cosmo woman of ten years experience, Miss here in Kew York. I rather think that Hamilton and Hamilton Gibbs, were Nagel, just a short time ago, hrought she let it slip unintentionally, but I very interesting. There ,was also Coun­ that most famous. of newspaper features, found out that she will run for the tess Caroli, whose husband was first the interview, within reach and audi­ nomination for registrar of the city. president of the Hungarian Republic. bility of every radio fan. It pays 812,000 a year. I just finished "It is very interesting, and I think I The scheme is clever. Nearly every­ speaking to the city editor of the New shall bring more newspaper features to one wants to become as nearly acquainted York American, and the air. I plan to as possible with famous people, hut it he has congrat ulated start a radio column seemed a difficult matter to bring the me. and become the first celebrities to the public through radio. "That iust goes radio columnist. Those who could sing or play an instru­ to show,': she con­ The public will be ment, of course, were immediately tinued, "that the asked for a name for brought on the air, hut it remained for radio has unlimited the column and con­ Miss N agel to bring those who conquered possibili ties. Just at tributions like those art in its more inaudible forms hefore present knowledge used in newspapers the microphone in a satisfactory manner. of who will run will be accepted." for registrar is ,"ery Rosario Duprez She Gets the Ce lebrities important, and the is another favorite A LMOST every person of importance fact that a woman from \ GBS. She .L\. in New York and visiting the city will do it makes the is the "Perfume and has spoken before the WGnS micro­ scoop valuable." I'ersonality" lady phone through the efforts of l\Iiss Nagel. who believes that She takes them there, and then, with her How She Does It per fu me, properly newspaper instinct and ability, draws H E then told me used, will enhance forth their thoughts, their hopes a nd an1 - S about her job of the personality of bitions for all the world to hear. Fay interviewing celeb­ a ny wOman. Miss King has called Miss Nagel the "news­ rities, and how, by Duprez, unfortun­ paper woman of the air." her clever questions, atoJY, cannot be seen

She got a "scoop" the day that I she draws informa­ I on the radio. Un­ visited her for an interview on her work. tion from them .- fortunate it is, for \Vhen I approached the beautiful studio which they proba­ she is the essence of on the seventh floor of Gimhel Brothers, bly would never di­ ARY MELISI I./amous Broadway cha rm and person­ having passed a group of people who were vulge in another M stage star, was one of the first celeb­ ality. WGllS, how­ relies to be inlervLewed by M us Nagel sta~ding outside of the glass-windowed way. ever, has many other from WGBS. The radio audience en­ studio, I found that Miss Nagel was on " I have inter­ joyed her demure confessions of stage ambitions, besides the radio. viewed hundreds' of life, but they would have enjoyed them linking newspaper She finished her interview and dashed famous people. I much more if they could have seen the work and perfume for the telephone. "A scoop," she said, can tell you some of lady in question. (M. Kesslerc Photo.) with radio. 28 RADIO AGE for July, 1925 What the Broadcasters are Doing A Station \ Where They \ Broadcast ~j ,-_ ~'Personality'" ~~ ------.-: .. --. -.. ~~ /'",~ ...... ______.J/{

By C. Clyde Real Joy Cook, who Dispensers Knows His atKH} Keep the Home ' Hollywood f/ as Marconi / Fires Knows His Burning in Radio I California,

Three oj KH)'s sCintillating stars are ~hown above, in their proper atmospheric setting, From left to right (hey are "The Sand­ man," who lulls the children to sleepy land, "Uncle J ohn" Daggett, / the Gooti Samaritan of KH), and on his knee, the little Queen Titania, who is a f airy optimist jor thol/sands of hard-working Californians.

HEN Signor \larconi inyented has epitomized, is that intangible a n(1 ca ted KHJ to the horde of inhabitants the Wireless Telegraph, little did in(lescribable force which, of necessity, of Radioland on April 13th, 1922. Like W he think that in the near future must come from within. Which, re­ Aladdin's magic lamp, Uncle John has this same great invention would advance duced to un(lerstanding English, only wrought miracles with this magnificent with such strides that Personality s hould mea ns t hat, to possess Personality in a . broadcasting station. KHJ has bright­ some day be broadcast to the inha bi­ marked degree, One must radiate that ene(l more homes of sorrow, brought more tants of this universe. magnetic force or power from a most harmony and joy into homes of discord, Although it may souncl like another dynamic source-the heart! And that than any other three stations combined. Hollywood Press Agent's stunt, this is the sole reason why Uncle John, direc­ And this is because his attitude towards phenomenon has cer tainly been acCOm­ t orial wizard of KHJ, has such a won­ his duties as an annOunCer has been that plished at station K IIJ, The Los Angeles derful personality-he has a magna ni­ of a minister of humanity, and his cheery Timl's, Lus Angeles, California, where mOu s heart, and his Radioland converts voice has COme to mean as much in the none other than John S. Daggett, affec­ a re becoming legion. home as the teachings of the scripture. tionately known to Ra(lio fans as Uncle Bringing to this position of announcer KllJ'S "Father" John, works this miracle with a resonant a splendid college education and the voice which, according to motion picture THIS famous broadcasting station invaluable experiences of a successful st(lndanls, registers "personality pi us," owes its existence, perha ps, to Uncle newspaper man, there is little wonder' Personality, some great philosopher John's genius, for it wa s he who de(li- that Uncle, John's name has virtually RADIO AGE for July, 1925 What the Broadcasters are DOing 29 become a household term in the helm of the good ship Rroadcast! osopher animates them with his magic Southwestern United States, and And not all of Uncle John's pro- fiow of metaphors nad similes, so tha t wherever the powe rful KHJ broad- , grams are solely entertainment. Pro- grim bugbears and obstacles are soon castin~ station can be .....-.::;:1:.:;;.~::-::~':--~~"~' ;,;;, fessor Syh'ester Hert- con\"erted into scintillating rays of heard. For Uncle John zog lectures to the sunshine. has seen fit to arrange youngsters, in the programs which language wit h Queen Ti tania appeal to e .... ery ~ I which they are N D last but not least of the legion of member of the . r' familiar, u po n A KHJ broadcasters is the famous 'fami Iy, with a f ' \ su bjects w hi c h Quee n Titania, who broadcasts the inner­ 'dew to entertain- \ stimulate thought most workings of Fairyland every Tuesday ing and enlighten- ' l action, compelling night. In conjunction with her father, ing his great fol- them sub con- The Sandman, who also writes and lowing of Radio I ~ sciously to master directs these unique sketches, Queen fans, for he has a i precepts and quo- Titania and Uncle John broadcast the penchant for ~, tationswhichthey most instructuve of juvenile programs, broadcasting the /' thought impossi- accompanied with the most melodious best talent obtain- , ble before. This of music. able anywhere. is conducted dur­ Hundreds of children, ranging from Thanks to KHJ ingthe " C hildren's fi\ e years to fifty, throng the auditorium and its progeni­ Hour," from 6:30 on these nights and are taken for a tor, Uncle John, to 7:30 p . m., a pleasant journey through the my1t ic concerts of the time which all realms qf Fairyland, under the personal highest type can G. Allison Phelps is known as the children in homes guidance of the diminutive Queen Ti­ be heard in one's Radio Philosopher oj KHj, Los An­ eq uipped with tania. home. KHJ is geles. Usually philosophy is either radio sets hold During its brief existence KHJ has probably the only dry or preaching. But not the way most sacred. They been responsible for more innoyations, station which has "AI" tells it. He makes you cry Jor are also treated to perhaps, than any other stat ion on the on its staff an mOre. special readings Pacific Coast. I n addit ion to the afore­ accomplished and from the Bible by mentioned feat ures, l" ncle John has famous musician. In the person of Uncle John, in that inimitable "oice inaugurated Saturday morning broad­ Claire Forbes Crane, Radio Editor of which children recognize as readily as casting classes. All persons are eligible, the Times, KHJ boasts a pianist who they do their parents. providing they register in advance. has been soloist with such large musical Another feature of KHJ, which has This novel Radio instruction is deemed aggregations as the Boston Symphony aided people in solying their daily prob­ One of the greatest constructi ve.influences Orchestra, the Los Angeles Philhar­ lems, is the \\ ee kly lectures by Fred C. to,\ ard a better understanding of radio. monic Orchestra, and others. \Yith i\Ic~abb on the "Care of Gardens." While performers appear before the the technique acquired as associate In Over fifty-two, eeks of constant broad­ microphone, Uncle John stations himself artist of !\Iadame M elba, Arthur Hac­ casting, 1\1r. l\lc:\abb has done such down in the opt:rating room the better kett and other renowned artists, she creditable work that his bulky daily mail to judge of the pupil's aptitude at broa d­ brings to Radioland a ,'eritable "Open from grateful housewives attests the casting, and at its conclusion he lectures Sesame" to shut-ins with musical long­ results obta ined. Then Harold Swartz, to the class upon their broadcasting ings. Under her artistic guidance the One of America's most promising sculp­ from a radio point of view. This COn­ musical programs of KHJ have thrilled tors, delivers a wee kly lecture on "Art." structive criticism is also broadcast. music lovers throughout the nation. "Care of the Body" talks are broadcast making it possible for all members 6( by Dr. Philip ~1. Lowell, a recognized radioland to learn the profound seCrets His Universal Appeal authority on this subject, while Cap­ of broadcasting. UT Uncle John's magical Radio wa nd tain Salisbury and other well-known When we radio COn verts sh uffle off this, B is not confined to classical music. globe-trotters tell of their thrilling mortal coil, we no doubt "t\'iIl consult the His musical programs are sO arranged experiences in foreign countries. R ecording Angel to ascertain our respec­ as to carry the universal appeal, running tive positions on the great list of those . the gamut of musical emotions in the Talks Easily U nderstood who sen'ed their :\1 aster well in human race, Just to proye how broad R, l\IARS, BAU~IG .\RDT, noted radioland. If so, we no doubt ",ill a scope and range these musical enter­ D astronomer, de livered a lecture find that Uncle John's name, like tainments cover, permit me to quote every \Vednesday eve­ Abou Ben Adhem, verbatim the mutterings of an alkili­ ning for o ver a year heads the list, coated miner from the great open spaces: upon astronomical su Ir "Out On the Mojave Desert we gets jects, couched in . (The fore­ mighty lonesome; times we don't keer such simple lan­ going lLcco1!nt if we Ii,;e or die, and along comes Uncle guage that the isthesecondof John with One of his side-bustin', gun­ layman could ac­ an i1% teresling tot in' musical fests which makes us quire a fair work­ series of articles plumb ashamed of ourselves' for e,'en ing knowledge of on CaliJornia thinkin' of kicking off!" the rather myster­ radio stations, And through all this good samaritan i 0 u s science of work of broadcasting cheer and enter­ astronomy . The wh ich are known tainment runs that indescribable force "Ra dio . Philoso­ from coast to -Personality . \\'hy, the entertainers pher," G. Allison coast for their selected by Uncle John's inborn genius Phelps, has written excellence. The fairly exude it. So thoroughly saturated and broa dcast over fi r$! of this with it are these skilled entertainers and thirty-six e ssays series appeared educators that they proceed to broadcast on momentous in the Ju ne it to the many radio fans with astonishing subjects, which are RA DIO A GE , results, You can feel the personality troubling people and other eq1tal­ of various musicians, "ocalists as well in the ordinary E. K. Barnes is assistant manager oj ly in teres Ii ltg as pianists, in your very home, 1\Iost walks of life. Tak- KHj and the boy who helps kee p the stories 1(1'U be miraculous and yet a pleasant possi­ ing the smudgy wheels moving day and night at this bility in this day and time, with such commonplaces of ever-popular haven oj "Kindness, Hap- published i n an a genuinely human annOuncer at the life, this wise phil- pine.ss and joy," early issue.) 30 RADIO AGE for July, 1925 What the Broadcasters Are Doing

• Ten Cotntnandtnents for the Broadcast Listener

While excellent radio reception is frequently possible during the warm months, the best long distance records come in the Winter. A reasonable attitude will help the listener here. He should remember that he cannot expect every act in even the best vaudeville performance to be tremendously amusing and just what he wants, nor can he expect the weather every day to be clear and pleasant. Similarly he must not expect every day to be just right for long distance radio reception. N ow and then a Swruner storm may interfere with both radio and picnics. The listener should become acquainted with his local stations and enjoy them during the Summer, and be satisfied with the long distance records he has made, or will make, in the Winter. In other words, he should get the best there is in radio during all seasons, and above all he should be reasonable.

If the listener lives rather far away from all radio broadcasting stations which he wants to hear, there are several things he can do. He can lengthen his aerial wires and increase their height from the ground. Both of these measures. make the signals louder as a general rule. He can add an audio frequency amplifier unless, of course, he already has this instrument. He can also increase the voltage of his "B" battery or plate battery up to 9Q or even 112 volts (that is, to four or five of the usual 22Yz-volt units or blocks). He can use a more sensitive loud speaker, or content himself with head set operation. He should also tune more carefully so as to get the very loudest signal whieh his set is capable of giving. If there is a tickler adjustment on his set, he should learn how to use it so as to get full volume of signals. And he should remember that the good results he will then get are going to be even better results in the Winter. If the listener is very near a powerful broadcasting station, he may get excessively loud signals from that station and have difficulty in picking up other stations when the nearby station is in operation. In extreme cases it is not possible to get the distant station at all under such circumstances any more than it is possible to hear a whisper from a dis­ tance when someone else is shouting nearby. Still a good deal can be accomplished.

There are ten good rules for broadcast listeners: 1. Don't try to hear Australia in mid­ 6. For the new longer waves above 450 summer. Be satisfied to enjoy the nearer meters, use a condenser connected between stations most of the time. the aerial and ground terminals of your set. 2. Don't be disappointed if an occasional 7. A little patience in· learning to handle storm interferes with your radio evening. your receiver yields rich returns in satis­ There are many fine concerts coming. You faction from fine signals. Remember that can't expect to find a pearl in every oyster "Rome wasn't built in a day" and keep on nor to receive a record-breaking concert getting more and more familiar with your every night. set and how it works. 3. If you want louder signals, use a longer aerial, more tubes, higher plate 8. It is a good idea to read the radio voltage, more sensitive loud speakers and column of a newspaper or a good radio more careful tickler and receiver adjust­ magazine or two. It helps you to know' ment. how your set works and keeps you up-to­ date in radio. Information of this sort is 4. A pleasant signal filling a moderate an aid in getting the concerts loud and size room should be enough to give satis. clear. faction. It is not worth while producing signals which deafen the neighbors. It is 9. Ask your radio dealer for advice; he wasteful to insist on tremendous signals can probably tell you what you want to which are generally less pleasant than know and will be glad to do so. The moderate signals. manufacturer of your set is also willing to help you get the desired results from its 5. If your local station comes in too use. loudly and drowns others out, a smaller aerial will help in tuning him out, with a 10. Do not throwaway the direction smaller condenser connected between aerial sheets or booklet that came with your set and ground. And if all measures to get and with the· tubes. Read all such material rid of the local station fail, why not enjoy carefully now and then. If you have lost his concerts? He is working hard for you the direction sheets write to the dealer or and it is nobody's fault that you are so manufacturer for another. The direction close to him that you are bound to hear sheets answer most of the questions which him. Broadcast stations have to be closer have been. puzzling you and preventing you to some people than to others. from gettlng the best out of your set. (CoPYficbt. 102$. by Radio Ago. lao. ) RADIO AGE for July, 1925 What the Broadcasters Are Doing 31 Favorites of MOVIEDOM Give Snappy Show at WIP'

Fans Gel (-- • '- '''Ifr....."" -'- ~ r Real I ns ight f I nto Adventu res of Famous S tars

HILADELPHIA:-one of the most unusual gatherings of famous stage and scrcen folk was hcld last month. P Moving picture starS of the :\Ietro-Goldwyn picture COr­ poration, togcther with such famous mcn as Marcus Locw and notcd stage stars, gathcred around thc microphones in thc Studio of Station WI P, thc radio broa(lcastcr of thc Gimbcl storc, to cntcrtain thc radio public a nd to ansWC r a ll personal questions sent in to the station. It was a real party-the starS sang, dincd, danccd to two orchestras; and thc microphones did full duty all the while. Lillian Gish, Jackie Coogan, Barb,1.ra LaMarr, Johnny Hines, Mae Busch, Dorothy l\Iackaill, Marion Davies, Anita Stcwart, Harry Morcy, Dagmar Godowsky, Louise Glaum, Fritzi Brunette, Ben Finney, Flora LaRrcton and many more Screen players. Raymond Hitchcock, Eddie Ca ntor of "Kid Boots" fame, with Mary Eaton and her sistcrs, Doris and Pcarl, Cccil Lean and Clco lVlayficId who made .. ~o, No, Nancttc" famous and the leading mcn and women of the two "l\(usic Box Rcvuc" shows rcprescntcd thc stagc an(l Broadway. ~ils T. Granlund, Above, JackIe Coogan in a speculahlle mood before appeartng before the \X/IP "mike" and telling his innermost secrets to ahost of radio admirers. Mae B usch, popular leading lady. is the de­ mure m iss at the lower left , She was one of the principal speak­ ers on this all-star I7Wvie program from the Philadelphia station.

famous "~. T. G." of Station WH~ in New York City; ~lar­ cus Loew, president of the Metro-Gold wyn Picture Corpora­ tion and head of thc Locw chain of theatres, a nd thc grea t "Sir Joseph" Ginzburg, Broadway's biggcst "nut." Plenty of Humor LI 1\1. OROWITZ, the famous "Emo" whose wcckly movie E broadcasts from Station \VIP have crcated a sensation all o .... er thc country, a rranged thc party a nd was thc an nounccr for the cvcning. "Emo's" witty rcmarks, aided by thosc of Johnny Hines, to say nothing of the other comedians prescnt, made thc radio scts bulge with laughter. The party was strictly informal. Most of the stars spoke on the impulse of the moment. The movie fans who have seen their favorite screen star as many times as they possibly can, had the opportunity to hear their voices, And if you wondered why Dorothy !\Iackaill bobbed her hair, or just what Barbara Lal\Iarr thinks of vamps, or any of a thousand questions that run through movie fan's heads, you found out if you hea rd this unique program. This idca of having movie stars speak from big broadcasting stations is meeting with more and more fa,'or every day. For instancc, at \VG~, Chicago, recently, according to dispatches recei"ed at \\'IP, Gloria Swanson, the prominent Hollywood rcsidcnt and fashionably cinema actress, consented to be "intcrvicwed" by thc Announcer, the questions in the inter­ view ha ying becn sent in by interested listeners. This is but one cxamplc of how movic stars are gaining wonderful publicity for thcmselves as well as providing more or less amusement. 32 RADIO AGE for July, 1925 The .Magazine of the Hour Look Out for , , , , THE RADIO SPIES By FREDERICK A. SMITH Editor. Radio Age T IS somewhat noticcable that in t he Radio Corporation of .\merica also included Johnson in the office. Tlowlby's affidavit reads as spite of the sensationa l nat urc of drawing. of machines and samples of products made follows: chargcs made against the Radio by the De Forest Company. . "She then admitted in the presence of Mr. Harley I Details of how Harley is alleged to have placed that a t the time I had Questioned her she was in the Corporation of America in the New his agents in the De Forest establishment and of his employ of the Radio Corporation of America, and Jersey Courts. comparati \'ely few radio employment of Dc Forest employes to furnish him that she had secured her position ,vith the De Forest publications and ncwspapers gave pub­ with stolen information a re also contained in the Radio Company under instructions from Harley. licity to the astonishing accusations made affid avits. Harley confirmed her statement. and they ioked by the De Forcst Radio Company. General Electric Accused about my catching Miss Johnson at the De Forest plant. and that [ had procured her discharge. and RADIO AGE is puhlishing thcse facts President Theodore Luce of the De Forest Radio now [ was seeking e mployment with the Radio Cor­ for the reason that both parties to the Company. in an affidavit. alleges that the General poration of America." prosecution are big factors in the radio Electric Compan y. with which. he a sserted. the Radio At Harley's request Bowlby took his wife to the industry. We believe that it is due our Corporation was in combination. had succeeded in Broad Street office of Harley. who said he had other readers to tell them the truth about this bu }in ~ up t he Electron Relay Compa ny of Toledo. o peratives in the De Forest plants besides Miss industrial scandal. not rermitting the and cut off from t he De Forest Company its source Jo hnson. He offered Mrs. Bowlby a position. which of filament wire. she refused. fact that the Radio Corporation of " If the defendant and its associates, the General America is the biggest radio ad\'crtiscr Electric Company and the Westinghouse Electric Offices Kept Secret in the field to dctcr us from adhering to a n,\ :\lanufacturing Co mpany. can control the fila­ Bowlby was employed as special investigator under the straight line of editorial responsibility. ment wire output. they can, of course. prevent Harley from May. 19lt, until January. 1925. and he Among publications which ha\'e ghrcn competition in vacuum tubes," he adds. reported reJ:ularly in writing to Harley in Rooms space to this situation are The J\ew No statement was fo rthcoming yesterday from the 301. 302 and 303. at 25 Beaver Street. Ra

Dorothy and Mar­ jorie: Moline are de­ termined to get across Jac k Nelson's j uven­ .le idea even if they have to dres9 th" part, as shown in the photo , Naturally. they have succeeded

How the Alert Jack Nelson lS Making Us CHILDREN Again RADIO SH OULDiV'T BE TOO SOLEAIlV, IS HIS DOCTRIIVE ACK r\ELSOX is a great fa\-orite spceches, sad music and unintcrcsting popular vaudeville artists, come attired among the kiddics. His best claim programs, according to J ack. lie is an as little girls when they cnter Jack's J to famc in that line li cs in thc fact a nlcnt believer in thc policy that a ny­ st udio in the Palmer lIouse, Chicago. that hc has lived among thousands of thing light-hearted a nd juvcnile will "go Xot that t he listeners can see them, hut orphan boys and girls at :\looscheart, over" with a radio audience much bctter Jack describcs thc m picturesqucly and Ill., the city founde<) by 'thc Loyal Order tha n any other form of e ntertainmcnt. then lets t hc m "do their stuff." Thcy of l\Ioosc t o carc for children of dc­ By this J ack does not advocate a con­ cut up for all they're worth, and the ccascd mcmbers, I n his capacity of tinual round of bedtimc stories, for he radio \V'avcs virtually ripple with laugh­ director of thc ?\Iooscheart radio station, has ne\'er fe aturcd that sort of broa

DEVICES R adio Age Insti tu te displaying t his seal ha ve been tested l\1anufacturers' Testing Service and a ppro ved by E},ffiERS o f t h e staff of RADIO AGE will be pleased to test devices the RADIO AG E M a nd materials tor radio manufacturers willi the object of deter­ INSTITUTE. mining their efficiency and worth. All apparatus which meets with the appro val of vanous tests imposed by members of the technical Apparatus illus­ staff of RADIO AGE WIll be awarded our endorsement, and the seal shown to the right will be furnished free of charge. Material, for tra t e d and de­ testing should b e sent to scribed below haa auccessfully passed RADIO AGE INSTITUTE our te..u for July. 504 N. Dearborn Street , Chicago, Ill. 1925.

Test' No. 76. STRAIGHT-LINE­ WAVELENGTIiCON­ DENSER. Submitted by the manufacturers. Silver-Marshall. I nc .• of a:!1'iI1I1:l111 1\0 S . Wabash Ave .• Chicago, III. llus con­ denser is a new low loss condenser designed for perfect S-L-W tun­ ing. I t is of the single­ beanng type, eqUipped with a long Cone brass bearing. adjustable. and tension adjustment mounted on. but independent of. the T est No. 70. WET "B" BATTERIES. submitted bearing. All plates are of heavily hardened and by the Kelman EleCtriC Co. • Rochester. N . Y Con­ flattened brass. entirely silver-plated. as are all Cur­ sistsof twelve cells in glass Jars. set in a wooden frame. rent-<:arrying surfaces ThIs feature. in conjunction Tops are provided with vents for filling with d istilled wIth the use of a minimum of lugh-grade msulatlon well out of the eloctr<>-Statlc field. resulls in thIS con­ water. There is a suffiCient plate area to allow a T ..st. No. 73 KELLOGG SHIELDED TRANS­ generous milliampere capac ity for use In:recelving denser havln.G. even lower losses than many laboratory FORME RS Codes 50) and 504 were tested. having standards. 'Ine single end-plate. as well as the shape sets where a wet B battery Is desired. A card giving been submitted by the makers. the Kellogg SWitch­ of the plates. is responsible for the very low minimum detailed instructions for filling the battery originally. board and SUfJply Company. 1000 W. Adams St .. capacity and the exceptionally high capacity ratio. and for watering and charging it. accompanies the Ch·lC8go. III. These unshielded types of audio trans­ Instead of separating by wavelengths. with this battery, which arrived in good condition as a result formers are of 4 1-2 to I and) to I ratio respectively. new S-L-W condenser it IS possible to separate stations and over a period of strenuous tests were found .to of good packing. Tested and approved by RADIO produce a really d istortlonless amplification. CalSIS­ by kilocycles. thus inSU ring greater selectivity and AGE Institute more separation of stations. Comprises latest design tendy. The design is exceedingly simple. very high in low loss construction. Tested and approved by grade wire being used, The tops are of sheet bakelite. Satisfactorily passed the tests and reqUirements o( RADIO AGE Institute the RADIO AGE Institute.

Test No. 74. FILAMENT WARNINGSWITCH. Sam­ ple submitted by The Yaxley Mfg. Co.. 110) W . Monroe St.. Chicago. III . Consists of a single hole mounting fila­ ment switch and socket for a mmiature light. the light in parallel across the A battery through the switch so that while current is On the light is illuminated. giving warning current is being used.. This light sits back of the panel and a bezel of colored glass permits the set-owner to see Test No. 71. CONTINENTAL 2-GANG CON­ I t. It serves as a warning to Test No.. 77, JEWETT SUPERSPEAKER CON­ DENSER Submitted by Garoner and Hepburn. the radio fan who gets ready SOLE. A quality loud speaker. submitted by .the to turn in after a strenuous Jewett Radio and Phonograph Company of P ontiac. Inc, 2100 Washington Ave .• Philadelphio. Po. Con· OX cha:..., that NS filaments are st ill lit. and should sists of a t wo gang variable condenser. well made and M ·lch. The hom in the Superspeaker console IS made be extinguished in the interest of battery economy. o f the same materials as the ~per-speak,:r hom. With s uitable where tuning of t wo inductances simul­ Tested and approved by RADIO AGE Institute the exception that the fInal finISh coats being enclosed. taneously IS desired. Or It can be used with the two are not necessary. The hom floats within the cabinet. halves in series to decreasc the capacity of the con­ and IS thoroughly padded on three s ides w ith p iano denser. Tested and approved by RADIO AGE In­ felt. there being a resalanCC chamber below the h?m. stitute. which adds gready to the excell~t . tonal ~alltles produced by this s peaker. The Unit IS of the Jewett Test No. 75. REMOTE CON­ Vemco Design. Tested and approved by RADIO TROL LIGHT. Also submitted by the Yaxley Mfg Co., of Chi­ AGE Institute. cago, Ill. This device consists of a single hole mounting brace and socket for m in iature Itght. for use at a point other than right on the battery switch. It is known as a remote control light . I t also . serves as a warrung that filaments ~ are lighted. T est<-d and approved _~--..... ~ by the RADIO AGE Institute.

It.. 31 0

A ROUNDUP OF HOOKUPS- Test No. 78. REMO RADIO TUBE REVIVER. Something you've never Submitted by the manufacturers. the ~emoCorpora­ Test No. 72. CONTINENTAL LOW LOSS AND t ion. of Merid en. Conn. This device was PUt on the JUNIOR CONDENSER. Submitted by Gardner seen before market in response to the popular demand for a tube and Hepburn. Philadelphia. Pa. It is known as the reviver. The Remo reviver has twO 5OCkets. for Continental 10-106S condenser, With the vernier large and small tubes. and tests showed that tubes arrangement consisting of the Junior condenser in the August waning in efficiency. if placed in the Remo reviver. shown at the bottom of the above lIIustratlal. It can would practically regain their old hfe. Certain periods of time. according to the degree of age in the be used separately or in parallel With the Io-Ioss as RADIO AGE tube being tested. were necessary. The reviver a means of fine tuning. Tested and approved by connects to the electric light socket. Tested

A Timely Discourse on Conventional Radio SYITlbols and Crystal Detector Sets By JOHN B. RATHBUN ONVENTIONAL radio circuit dia­ Copnicbt: 1925 left. whicb may indicate the output of any radio receiving circuit. Abbreviation (PH). The polari­ C grams, the short-hand of radio, have ty may be marked by (+) or minus as shown, always proved a sticker to the tyro in or this may be omitted at will. The positive con­ this science, and it is certain that many a nection of the phone cords is colored red and this red strand shOUld be connected to the ( + ) connec­ prospective builder has contracted a bad How to Understand tion of the circuit. At the ri"ht i. the symbol for case of cold feet and quit the game when the hom or loud speaker which can also be marked he was brought face to face with the All Radio Symbols; with the polarity. curley-cues and zig-zag lines of the tech­ 7. CONDENSERS. A "fixed" condenser eon­ s ists of alternate .heet. of tinfoil and paper or mica nical diagram. Not being very familiar Giving the Crystal compressed into a compact pile, and add. with the apparatus itself, it is no wonder "capacity" to the circuit, an effect opposite to that the prospect of learning still more that of an inductance coil. The symbol for a fixed I ts Merited Attention condenser i. at the left where the abbreviation is of the technique filled him with dismay. shown as (K) and where the capacity in micro­ However, when these symbols are once farads is also added where advisable. A VARI­ understood, they are more easily read ABLE CONDENSER used for tuning inductance. transmitting station. The abbn:,,;ation is tbe is shown at tbe right, wbere the rotor plates are and understood than the picture diagrams letter (L) and its magnitude is generally expressed indicated by the curved line and thc .tationary or for they show the functioning and general in millihenries, or by the number of turn. of wire. stator plates arc shown by the short straight line. principles of the circuits far more Clearly 2. IRON CORE CHOKE. This consist. of " The Stator (Straight line) shOUld go to the grid of .. to the- experienced eye than pictures of great many turns of wire wound around a core of tube. while the rotor is connected to the ground soft steel wire or thin steel sbeets called "lamina­ . ide or (- A) side of the circuit. Thi. condenser the apparatus. You can see the COurse tions." It is used wben a greater retardation must is also rated in microfarads (m. f.). taken by the current in the ditTerent be had than is convenient with an air core cboke. 8. RESISTANCES-RHEOSTATS. A fixed branches of the circuit at a glance, and and can choke back audio as well as radio frequency or unvarying resistance is shown by the zig-zag can immediately classify the circuit with currents. Values in henries or millibenries. line which distinguishes it from an inductance. For 3. TRANSFORMER-COUPLER (Air Core low resi.tances used for controlling the filament. of Ii ttle chance of error; something that Type). This transformer for radio frequency the tubes, its magnitude i. given in tcrms of ohms. I have never yet been able to do with the curr~nts consists of two coils of wire called respec­ For very high resistances. as used for grid leaks, picture type. However, the picture tively the PRIMARY (PRI.). and the SECON­ the resistance i. given in terms of MEGOHMS. DAR Y (SEC.) coils. Radio frequency currents abbreviated (MEG). diagram has its place in the scheme of passing througb the primary induce similar cur­ A RHEOSTAT or variable resistance is sbown things where the reader is not inte rested rent. in the secondary coil. thus affording a means at the right and is usually employed for controlling in theory, but simply in building some­ of "coupling" two circuits together magnetically. the fila me nt current of tube.. The letter (R) is used thing that will bring in the voice and In our diagrams tbe primary coil (PRI) is shown f or a rheostat, or resistance. with fewer turns than the secondary and is shown 9. BATTERIES. An "A" or 'filament battery music with the least delay and study. on the end opposite to the grid connection (G). or a " C" battery is .hown by the .ymbol at the left For the benefit of those who have not The other connections are the filament (F), the which consists of alternate .hort heavy lines and yet become familiar with the standard plate connection (P), the positive "B" battery longer light lines. The short heavy lines indicate connection (B) and the neutral tap (N) used for the negative (-) plates while thc long lines are the conventional :;ymbols used in radio cir­ certain neutralized circuits. Tbe abbreviation is positive plates ( + ). Each pair of these lines rep­ cuit diagrams, I have prepared the ac­ (RFT). and it may be tuned or untuned. the resents One cell. and it is the best practice to mark companying two pages of blueprints in former by a variable condenser. the voltage below it as at (6v.) anx1 the !ettcr (A), 4. VARIOMETER. This is a fonn of variablc (B) or (C) above it to designate thc type of b a ttery. which the more common symbols and inductanee used in place of the air core cboke. and A "B" battery is at the right where the dotted line ab breviations have been defined. In ad­ consists of a movable member (The Rotor) which indicate. a number of omitted cells, there being dition to the listing of the symbols, I turns inside of a stationary coil called the " Stator. ,. too many cells in a "B" battery t~draw them com· The abbreviation i. (VAR). By this means the ple te. Wben the battery is tapped at some low have taken up a short description of the inductive or choke effect can be varied through a voltage, as at (+22), the voltage of the tap is various parts used in the receiving cir­ wide range without condensers and the device is marked in this way. cuits so that the subject will be more frequently used for tuning a circuit inductively. It 10. POTENTIOMETER. This i.a de,,;ce which easily followed. may be tapped at the mid-point as sbOWD at (Q). looks much like a rheostat used for the accurate S. ANTENNA.GROUND·ARRESTOR. At control of voltages. gcnerally the biasing voltage s Circuit Symbols (Sheet No. 1) the rigbt is .hown the symbol fOr the antenna or applied to tbe grid of a vacuum tube. It consists 1. INDUCTANCE (Air Core Type). The aerial, abbreviation (ANT). In the center is the of a filCcd resistance of from 200 to 400 ob ms con­ hollow coil of wire or other inductance coil with an symbol for a ground connection (GND). and at nected across the battery and a sliding contact air core is sbown by a continuous scroll or helix the right is the convention for a lightning attestor wbich tap. off the drop of potential at any point of as in Item No. 1. Its purpose is to cboke back or (LA). the resistance, The polarity ~f thc slider also impede the 80w of radio frequency CWTent or for 6. OUTPUT - PHONES - SPEAKER. Tbe tuoing radio circuits to the wavelength of the symbol for the bead.et or pbones is sbown at the (Tum to page 38) Blueprints of Conventional Radio Symbols and Typical Crystal Receivers on pages 36, 37, 40 and 41

38 RADIO AGE for July, 1925 The }.t[agazine of the Hour (Continued from page 35) (SW) being used to vary the number of understandable signals on so small ao£l varies with its position, becoming negative at one turns in circuit. amount of current that it can be esti­ end and positive at the other. fit In Fig. 23 is a regenerative circuit with mated in millionths of an ampere; and 11. THREE ELEMENT VACUUM TUBES. one stage of audio frequency amplifica­ yet, with all of this delicacy, the appara­ The three elements of a vacuum tube are the filament (F), the grid (G) and the plate (P), al­ tion a type of circuit, very commonly tus is perfectly simple and so rugged thoU2h these parts need not be marked as shown. met' with. The detector tube (Tl) is a that it can withstand a considerable A --hard" amplifyine tuhe is indicated by a single soft tube while the amplifier tu be (T2) amourtt of abuse at the hands of the beav}' circle dTawn around the elements and as a hard tube is mucb used at present for a detector as is a hard' tu be, as will be seen from the listener. well as for an amplifier. When a soft detector tube circles. A coupler is used for tuning, To most of our readers who have had must be used, two circles are used, as at the right. having the primary coil (LI) and the experience only with the cheap and simple Tbe word amplifier is abbreviated (AMPL) and secondary coil (L2 ), this being used single-slide, single-circuit crystal detec­ detector by (DET). sometimes instead of the abbreviations tor sets sold on the open .market, the 12. TWO AND FOUR ELEMENT TUBES. A two element tube or Fleming valve is indicated at .. PRI" and "SEC." The secondary is crystal detector is considered only in the the right and bas the filament and pla.te but no grid. tuned by the variable condensor (Kl). light of a toy having only a very limited This is most generally used as a rectIfier for charg­ F or regeneration we have the tickler coil use in reception. This, however, is not ing storage batteries from alternating current, hut is also used as a detector. The four element tuhe (TIC) placed directly above the second­ the case, for with proper attention to the at the right bas two grids. ary coil (L2) and connected with it by details of construction and with as much 13. GRID CONDENSER AND LEAK. This means of an arrow. The arrow in this care taken with the tuning units as we symbol used with detector tubes is simply a combi­ case indicates that the two coils are pay to the construction of a tube set, the. nation of the symbol of a condenser and that of a resistance (The leak). The leak abbreviation is inductively coupled by a variable rela­ performance can be greatly improved in (GL) and the gri~ condenser i.s (GC~ . . If.either of tion; that is, that the position of (TIC) regard to distance range and signal these items is vanable, then thIS fact IS Indicated hy can be varied in respect to (L2). The strength. If we constructed our tube dTawing a slanting arrow across it as at the right. grid condensor (GC) and the grid leak sets with the same lack of care and with 14. CRYSTAL DETECTOR. A crystal detec­ tor is indicated by an arrow head for the cat­ (GL) are shown connected to the grid the same primitive tuning systems that whisker and a small block for the crystal. of the tube. are used on commercial crystal sets, we Abbreviation is (CD). Cu rrent for ligh ting the tube fila­ would not get very much better perform­ IS. AUDIO (IRON CORE) TRANSFORMER. ments is supplied by the six volt "A" anc~ Single-Slider, single-circuit tuners An iron core transformer, commonly known as an battery which is connected so that the are not conducive of good results with audio frequency transformer, is used for increasing the voltages of ClUTents apP':oltimating v.oice fre­ negative pole goes to the detector rheo­ either the crystal or tu be detector, for quencieS,lor audible frequenCIes. It conslst~ o~ a sta t (RI). The negative pole of the they cannot be tuned accurately in re­ primary winding (PRI) and a secondary wlDdlDg "A" battery connects with the negative sonance with the incoming waves, and (SEC) with a few paraDel liDes drawn between the coils to indicate the iron core. The fO';1'" connec­ pole of the "B" battery, and the latter there is always a considerable loss taking tions are marked as follows: (G) for gnd. (P) for is tapped a t the ( +22) volt point for the place that limits the distance and plate, (F) forJfilament and (B) for "B" battery detector current. The total voltage of \'olume. connections. These apply to vacuum tube connec­ tions with which the transformer is most commonly the "B" battery at (+90) goes to the The Crystal Detector Circuit used. Iron core transformers of a special type are I ast stage jack (J 2). A two circuit jack also sometimes used on radio frequencies. hut when (] 1) permits us to plug in on the detec­ primitive crystal detector circuit this is the case the fact will be particularly noted on UR the drawing. Ahbr. is (AFT). tor tube alone without amplification, or O consists of three principal units: 16. WIRING AND CONNECTIONS. . In without lighting the amplifier tube (1) The tuning unit, by which it is general wiring is indicated by very beavy hnes, (T2). Plugged in on (]2) we get the brought into resonance with the incoming and c.Jved by an arc where a turn is made. Where amplified Or intensified cu rrent for the waves, (2) The crystal detector employed two wires connect, a small OPEN circle is used to mark the connection as at (a). Where one wire operation of a loud speaker. for rectifying the radio frequency im­ crosse" ovr-r another, the crows-over is shown as at An iron core audio frequency trans­ pulses for the development of the audio (b). Connection posts or terminals for batteries, former (AFT) transfers the plate energy waves, and (3) The audio output mechan­ etc.. are sbown by a circle with a heavy black dot inside, as shown in a horizontal row. The letters of the detector tube (Tl) to the amplifier ism which converts the audio frequency indicating the "A"" CI B '" and 'C" hatteries are tube (T 2), and it will be noted that the electrical waves into mechanical' sound marked at the terminals. together with their terminals of t he t ransformer are marked vibrations (Phones). All three elements polari ties. In the case of the "B" battery connec­ tions the various taps are marked by the voltages in accordance with the points that they must be as perfect as possible if we are to a. at (+22), (+45) and (+90), hut the letter "B" connect. T h us (G) goes to the grid of extract the maximum output in the form is not used. (T2), connection (P ) goes to the plate of of sound, for the incoming energy is 17. TAP SWITCHES. r Tap switches used for tube (Tl), connection (B ) goes to the exceedingly feeble and must be carefully cutting out active turns in a coil should be COn­ nected so that the contact points go to the grid Or (+22) volt tap of the " B" battery, and utilized with the least possible loss. aerial side of the circuit with the hinge connected connection (F) goes t o t he (-A) through This means sharp tuning, a crystal hav­ to ground or on the far side from the grid connec­ the "C" battery. A fixed condenser (K) ing excellent rectifying qualities and an tion to prevent bodY' capacity effect. is shunted across t he secondary. A 4.5 exceedingly sensitive pair of phones, 18. INSTRUMENTS. Measuring instruments such as the voltmeter (VM). the ammete. (AM) or volt " C" battery is used for biasing the none of which a re in evidence in the u!:ual the hot wi~e amD1eter (HW A) a re 3hown in circles, grid of the tube (T 2) and the negative $2 .00 crystal detector set. In reviewing The polarity should be marked. and also the range pole (-) is connected to (F) of t he t ra ns­ the requirements, we m4st also remember of volts or amperes at at (0--10) and (0--5). former so t hat the current gets t o the to include an efficient antenna into the 19. JACKS. Jacks are specially arranged con­ tacts used for making temporary connections by grid of the tube through the windings. assembly, which should have greater means of plugs and may be of many types. At the Tube (T2) is controlled by rheostat length and capacity than the antenna left is shown the single circuit jack (J2) generally (R2). commonly used with tube sets. The used for the last stage connection and at the left is a two circuit jack (Jl) used for plugging in Fig. 24 is a typical re flex circuit with latter item is generally neglected in the between ,,-tages. These are by far the most common the radio frequency transformer (RFT) insta llation of a crystal set, with the types. and the audio frequency transformer result that very little volume or dista nce 20. S\WI TCHES. Different types of battery (AFT), the for mer being tuned b y the is had. Conservation of energy is a prime switches are shown. the left symbol being for symbolic diagrams while the second from the left is variable condenser (K2). A coupler is requisite. used frequently on picture diagrams. The switch provided with the primary (Ll) and It is here that the low-loss coil and the at the right is a double pole knife switch used for secondary (L2 ) by which the set is tuned low-loss condenser hold forth with beavy clUTents. to wavelength. T he grid bias on the particular advantage; spiderweb, honey­ Sample Symbolic Drawings tube is varied by the potentiometer (PO). comb or barrel-wound coils being of The rest of the parts have been explained great advantage in the construction of N SHEET ~o. 2 we show four repre­ before. O sentative circuit drawings which such a set. The phones should prefer­ include most of the symbols tabulated. ably be of the mica diaphragm class or Each symbol is lettered with the standard with very thin flexible metal diaphragms Crystal Detector Sets so that the slightest current in the coils abbreviation so that it will not be difficult ME, the crystal set has always to trace out the relation bet\,'een the o will give a maximum vibration. When seemed the most wonderful of all we look at the cheap phones ordinarily parts in the table and the corresponding Tradio receivers, for with this device parts in the diagram, supplied with crystal sets, with their we employ the feeble energy of the radio thick cast-iron diaphragms and their A simple crystal detector set, tuned by waves alone to vibrate the diaphragms the variometer (VA R) is shown in Fig. weak magnets, it is no wonder that of the phones without aid or reinforce­ reception is limited to 10 or 15 miles. 21. Here we have the symbols for the ment from local sources of energy. After variometer, crystal, aerial, ground, This would be almost the case with a trave~lng . fifty miles or so, there is still tube set if it were supplied with the same phones and two fixed condensers. Note suffiCIent energy left in the waves to that when two condensors are shown sort of phones. The feeble impulses move a .relatively stiff piece of metal and received demand the most sensitive and that they are numbered as at (Kl) and to produce the audible air vibrations (K2). In Fig 22 we have another single efficient equipment that we can supply known as sound. Further, it is an exhi­ if the crystal set is to be more than a circuit crystal set tuned by a simple bition of the remarkable sensitivity of tapped inductance (L), the tap switch mere toy for children's use. the modern headset which produces Please don't infer that I am recom- RADIO AGEjor July, 1925 The Magazine oj the Hour 39

mending the crystal set as a substitute While the complete theory of contact Galena, silicon, carborundum, cerusite. for the tube set, for I am not. I am rectification is not yet well understood, pyrites, perikon, radiocite, and hecite are simply bringing to your attention the I will explain the functioning and purpose among the most commonly used simple fact that the crystal set performance can of the crystal in a general way so that minerals, and in addition to these are the be wonderfully improved by a little care the beginner can at least ~et a working numerous synthetic crystals that bear a in the construction and that it is a most knowledge of its propertIes when in­ multitude of tra de names. A good galena desirable proposition for local reception stalled in the receiving set. I\Iechani­ crystal is probably one of the most sensi­ where we do not wish to go to the trouble cally it is very simple, consisting of a tive crystals, but it is not stable and must of installing batteries and similar com­ small piece of mineral called the crystal, be readjusted frequently. Silicon and plications. The crystal set has a field a nd a thin wire ma king light contact carborundum do not require so frequent all its own and is almost indispensable wit h the crystal at a sensitiye spot. In adjustment and are q uite sensitive if for certain purposes, and for this reason some cases, contact is had between two ca refully selected a nd mounted. The I believe that more attention should be crystals instead of between the wire sy nt hetic cr ystals a re in most cases stable pa id to the development of its perform­ and crystal, but in any event the radio and sensitive, and have the advantage of ance rather than to cutting down on the frequency current must pass through a having a greater effective area or more expense of construction, as has been done high resistance contact of some sort "hot spots " tha n the natural crystals, so heretofore. You cannot get long distance before passing through the phones, so that it is not so difficul t to adjust them. consistently, nor can you get full loud that the audio or "hearable" portion of For the catswhisker wire, we require speaker volume of the crystal alone, but the incoming waves can be developed. a metal that wi ll not corrode under you can get locals with good volume, Owing to the rapidity with which the ordinary atmospheric conditions and one clear and sweet, without the fuss a ttend­ radio wa vc oscillates back and forth, the that will maintain a bright metallic con­ ing the operation of a tube receiver. diagrams of the phones cannot follow the .tact area at the point where it rests on the 'Vhen loud speaker volume is required radio frequency currents in the recei\'er crystal. A copper wire will work well on local, with particular atte ntion to with most crystals, but a silver or gold quality, we can add one or more stages wire is better, as it doe~ not corrode or of audio frequency amplification to the get dull as rapidly. With the exception detector. Of course, we are now getting of the carborundum crystal, the cat­ back to vacuum tube complications and A ROUND-UP OF whisker wire should make very light batteries, but with very simple layouts HOOK-UPS contact with the crystal, working best we can obtain wonderful tone values on when only just barely touching the sur­ the loud speaker and a somewhat in­ in the Deluxe AUGUST IS­ face. With the carborundum detector a creased distance. Just as an experi­ SUE OF RADIO AGE. very heavy pressure is required, which ment, it is very interesting to add resist­ in itself is One reason for the stability of ance coupled stages to a crystal detector Never before have you seen such the carborundum, as the heavy pressure to discover what real tone purity is like. a galaxy of hookups, from the prevents the displacement of the contact The natural tone and life-like quality simplest though efficient crystal to when subjected to vibration. will be a revelation to you, and if you the most recent simplified super­ There has been a great deal of argu­ live within 25 miles or so of a broad­ heterodyne receivers. Radio from ment for and against the fixed crystal casting station, I am sure that you will its humble beginning to its present detector with the immova ble catwhisker, keep this circuit hooked up permanently. peaks of achievement in the Special but I believe that the fixed detector will Summer Number of RADIO AGE. prove best in the long run for the begin­ Future of the Crystal Set All basic Hookups. ner, at least, as it avoids the necessity of ONSIDERING the many 5,000 watt constant readjustment and the detuning C broadcasting stations now under THI·RTY PAGES OF DE­ effect when these a djustments are made. construction, and the increasing practice I t will perhaps be of interest to know that of re-broadcasting, it is certain that the LUXE BLUEPRINTS. the crystal has a great deal of effect in crystal detector receiver will find a mOre Order your Copy in Advance. t he tuning of the Circuit a nd very often extended use than has been the case in we can tune a station in and out by means the past. Increased power at the stations $2.50 a year. of the crystal adjustment alone. For the and the relaying of these stations at close 25c at your Newsdealer experienced crystal set ope rator, the intervals over the country will mean that adjustable crystal is therefore often an the crystal will take on a new life. .\t advantage, as it is an aid to selectivity least ten telephone companies have and tuning, particula rly where there are adopted local re-broadcasting systems as directly and nothing will be heard in the many strong local stations and other an additional service to their subscribers, phones if some sort of rectifier or "de­ interferences. and I do not believe that the telephone tector" is not inserted into the circuit . It is a good plan to g-et a number of companies will be the only people to These wa ves are "alternating," that is, crystals and then select the best crystal engage in this work. If the network of they flow first in one direction and then b y actual test. There is a great deal of re-broadcasting stations is fully developed in the other, and before we hear the sig­ variation among crystals even of the same the use of the cry stal set will be practical nals these waves must be made "uni­ make, and the only way that you can be in almost any part of the United States. directional" so that they will flow in one assured of t he maximum results is to One re-broadcas t station equipped direction through the phones but with select the best crystal from a number of with a good receiving set and a trans­ an intensity that varies according to the samples. mitter of moderate power will easily sounds sent out by the broadcasting The Hook-Up or Circuit cover a radius of 25 miles and will station. The cry stal detector with its efficiently serve crystal detectors in this contacting "cat whisker" wire acts as HERE are about a thousand different 50-mile circle. The expense of main­ such a rectifier a nd permits the passage Tcrystal detector hook-ups from which taining such a station is comparatiyely of onlv one set of waves that are flowing to make a choice, and all of them have small and can be borne by the loca l in the same direction. their adherents, who believe that they Granges or community associations with \Vith the radio frequency current rec­ have the only circuit worth using. Some a great saving to their members. Th~ tified, the " audio frequency" waves are employ variometers for tuning induct­ station receives the voice and music developed so tha t the diaphragms of the ances, ot hers use spidef\\'eb coils, vario­ from distant stations and then broad­ phones follow the slower voice frequency couplers, honeycomb coils and straight casts these signals through simple a ppa­ p ulsations, thus producing sound. Our solenoid coils in a ll sort of combinations, ratus to loca l listeners, thus avoiding the sta tion waves therefore consist of t \\'0 but as a matter of fact, a cl ose examina­ expense and trouble of arranging pro­ components, the high radio frequency tion will show tha t most of these circu its grams. So far, this arrangement has carrier waves oscillating at the rate of can be boiled down to six distinct classes. increased the total number of listeners about 1,000,000 dbrations per second, The type of !n~uctance. do<;s not c.han~e tremendously without appreciably affect­ and the audio frequency waves impressed the charactenstlcs of a CIrCUit as a 'clrcult; ing the sale of tube sets. On the contrary, on them that will range from a few hun­ it simply adds or detracts from its effi­ One re-broadcasting station states that dred to an upper limit of about 15,000 ciency by the sharpness of its tuning the interest aroused in radio via crystal vibrations per second. These latter properties and the losses occuring within sets has ~rea tly increased the sale of tube waves are produced by varying the in­ the coil. A variometer may show better sets in Its territory, and that a great tensity of the radio \Va \'es by "modula­ results than a simple tuning coil, simply proportion of the listeners now have tion," and are not actually an indepen­ for the reason that it can be more closely both crystal and tube sets in t heir de nt serie~. adjusted to wavelength than the coil­ homes. Tiring of the local re-broadcasts, There are a great number of minerals not because it is a variometer. An in­ and desiring different programs, they that will act as detectors to some extent, ductance is an inductance no matter what turn to their tube sets and tune in the but only a few that are effective enough form it may be used. distant stations for themselves. to be used in the practical crystal set. (Tum to page 42)

42 RADIO AGE for July, 1925 The Magazine of the Hotir

(Conti nued from page 39) a good degrce of selectivity by other ductance. The crystal detector (CD) is Fig. 1 shows the six basic circuits with means and without so much loss in signal best placed as shown and should not their relative audibility value, as de­ strength; hence, this type or circuit can be be mounted on the front panel where it is termined by the U . S. Bureau of Stan­ neglected for the time being. likely to be thrown out of adjustment by the jar of the hand every time we move dards. The relative signal strengths are Circu it With Co upler given in terms of percentages, and it will the tuning dial. be seen that the hook-up has a great deal OR the sake of selectivity we will con­ The tuning inductance (L1-L2) is to do with the reception, varying as it F nect our aerial and ground to the wound on a cardboard tube three inches does from 10 per cent to 85 per cent. detector circuit by means of an aperiodic in diameter and about 4 1-2 incles long. These diagrams refer only to the detector or semi-aperiodic coupler of the type so The primary winding consists of 12 turns circuit itself and do not consider the commonly use in tube sets. For the de­ of No. 24 D.C.C. wire, and a space of various methods of coupling or connect­ tector circuit we will adopt the circuit about 1-2 inch is left between this coil ing the circuit to the aerial ancl ground. shown in Diagram (B) to obtain the and the secondary coil (L2). Starting A varia Lie condenser is used for tuning greatest signal strength and will depend coil (L2), we wind on 55 turns of the same a fixed inductance in all cases. entirely upon the coupler construction size wire, and fasten the ends of the coil Diagram (A) shows a simple form of for our selectivity and tuning. This securely by passing them through holes circuit often used, which contains the combination \vill probably give us the punched in the cardboard tube. For inductance (L), the variable condenser best all-round comhination for signal strong local stations, it may be necessary (C), the crystal detector (CD) and the strength and selectivity and at the same to increase th1! distance between coils to phones (Ph) all conne<.ted in series. For time is simple to build and tune. 5-8 inch or 3-4 inch to obtain the required ordinary broadcast ing \ .'a velengt hs there I n Fig. 2 we have the schematic dia­ selectivity, but this space should be no will be about 55 turns of wire in (L) when gram of the complete circuit. The greater than actually required for the wound on a three inc h tube, and the ca­ coupler consists of the primary coil (Ll) complete tuning out of the strongest pacity of the variable condenser (C) will connected at one end to the aerial and st~tion. I.f the gap is much greater than be from 0.00035 m.f. to 0.0005 m.f. The to the g round a t the other end. The radio thiS, the sl~nal .strength will be reduced. audibility is 55 per cent. impulses from (L1) a re communicated to The tentative wire (g) and the experimen­ In D iagram (B) we ha \'e the same cir­ the secondary coil (L2) which is identical tal fixed condenser (Kl), are shown in cuit with the addition of the small fixed with the coil (L) in Diagram (n). A dotted lines as they ma y not be needed condenser (K ) connected across the cry­ variable condenser (C 1) is connected with the combination of parts used in stal detector. This fixed condenser acts across the secondary coil so that it can be your set. as a storage capacity for the wa ves and tuned to wa velength. The fixed con­ The condenser (C1) can be either a 17 adds considerably to the volume, as it denser (K ) connected across the crystal plate or .23 plate variable condenser hav­ supplies an additional current to the detector (C D ) serves the purpose al­ Ing a capacIty of 0.00035 m .m . to 0.0005 crystal. This addition has increased t he ready described. The phones (Ph) are m.m., but the latter is preferable. If you · audibility from 55 per cent to 85 per cent, in series wit h the crystal detector. do not wish ~o wind the coil yourself, you the maximum value determined by the .By means of the inductively coupled can use a neutrodyne transformer which Bureau. COils (Ll) a nd (L2) we can obtain much can bc' purchased complete and mounted The capacity of (K) depends upon the better selectivity tha n with the aerial and on the back of the variable condenser. nature of the crystal detector, but in any ground connecter! directly to the de­ Such combinations cover a wa velength event the capacity must be small to tector circuit. The selectivity depends band of from 200 to 600 meters, the range prevent by-passing much of the current largely upon t he dista nce between these of th.e a verage broadcasting stations. across the dectector. With some de­ two coils. The greater the distance the It is most convenient to mount the tectors 0.00025 m . f. is about right, greater will be t he t uning qualities where a pparatus on a 6 in. x 7 in. x3-16 in. p!1-nel while with other types this ma y be as there are many strong local stations. a s shown by Fig. 4 with the tuning dial low as 0.0001 m.f. or even less, A small Properly adjusted, it is possible to tune ( D) appearing on the front of the panel three-plate variable condenser ' will often in and out on a ditTerence of five meters as shown. The aerial binding post is at prove of value in getting the adjust­ wa velength, but with comparatively li t­ A:-.lT, the ground connecting post at ment correctly. tle loss in signal strength. With the GND, and the phone posts at PH. The In Diagram (C) we. have t he same cir­ aerial a nd ground connect ed directly to method of connecting to the aerial and cuit as in Diagram (A), but a fi xed con­ the det ector circuit, it is probable tha t a ground is also shown in this view the denser (K) is used to bypass radio fre­ nearby sta tion will come in all around ground being a connection to a wat~ r or q uency current around t he phones. The the dial, no matter how it may be turned. steam pipe. average audibility under a ll condit ions In regard to a crystal detector, it may The aerial should not be less than 60 is reduced to 45 per cent ; hence, this is not he said t ha t it is much more difficult to feet in length, and more than this is always an advisable addition. I n many get select ivit y with a cry stal t ha n with desirable where the necessary room can be makes of phones thOf"e is a considerable a tube receiver a nd t ha t ftreater care will obtained. With a crystal detector set amount of distributed caI,acity in the be required in the adjustment. The the mOre .a.erial wire that we hang up, th~ windings of the magnets and this fre­ ~rysta l has t he peculia r property of hang­ better Will be our reception, and any quently is sufficient to properly by-pass lfig on to a station even a gainst powerful length (L) can be used up to 150 feet. the radio frequency current aronnd the controls, and while it has 110t much dis­ .With two wir~s placed side by side, 150 inductance without the addition of ex­ tan~e or ~bi!i t y on wea k signals, it will hold feet long and With the set located in the ternal capacity. However, in case the on hkexnmjdeath tolfairly st rong signals. ( open country, quite long distances can be phones have a high ind uctive value with Under somc conditions it may be ad­ covered. However, with a 60 foot aerial little distributed capacity, a by-pass ( K) v.isab.Ie to conned t he lower part of the in a good locality, we can get good re­ may be necessary. Clrclllt to the ground connectIOn (GND) ception with fair distance, providing that Diagram (D) is a type of cry st a l de­ by mea ns of the short dott ed wire (g). the aerial is not screened by steel struc­ tector circuit often used On Wa ve-meters ~he rotary ~ lat e.s should a lso go to this tures such as steel factory and office and similar instruments where verY sharo Side of the Ci rCUI t (ground) as indica ted buildings, bridges, etc. tuning is necessary . The audibility is so by .the curv~d line at (C l) a nd the low (10 per cent ) that it is impractica ble stationary plat es are connected d irectly for a receiver and therefore need not be to the crystal detector (CD). discussed further. Its only virt ue is its . With. so.me phones, which have very H igher Power Licensed extreme selectivit y. little distributed capacity, it may help To Beat Static Diagram (E) a second varia ble con­ matters to COnnect the fixed condenser denser (C2) is employed in addition to (KI) across t he phones ( Ph) as indicated HE Department of Commerce has the original variable condenser (Cl). bl: the dotted lines. This is best deter­ Tannounced that favorable consider­ This sharpens the tuning considerably mlfied by actual test, aftcr the set has ation will be given to applications from and has a much greater audibility than bee.n built and connected up to the aerial. owners of Class B broadcasting statiorts the circuit in Diagram (D). The audi­ ThiS may be a 0.001 m.f. fixed condenser. for permission to use higher power with­ bility is four times as great as with ( D) Picture Diagram of Se t out requiring the increases to be made and is almost equal to that of the first in steps of 500 'watts as has been the tliagram. A complete drawing of the circuit with practice heretofore, providcd the sta-" Our last diagram (F) is the ultimate in all of tl~c par~ s in place is shown by Fig. tion~ .are situated outside of congested selectivity but has a very low audibility ~, the.lett ~ rs.1fi tillS drawing correspond­ reCeiving centers. factor. The circuit is split by means of l~g WIth slml!ar letters in the schematic In taking this action the Departme nt the coupler coils (L2) and (L3) so that diagram of FIg: 2. A detail view of the is endeavoring to satisfy the demand coupler coil is shown which is connected almost any degree of selectivity can be of broadcast listencrs that the use of to the vari~bl e tuning condenser (Cl), increased powcr be permitted in order attained but at the expense of a great the latter bcmg connected directly across to Overcome the existing static conditions loss in signal strength. We can obtain the secondary coil (L2) of the tuning in- which are making reception difficult. . RADIO AGE for July, 1925 The Jlagazinc of the Hour 43

HE material appearing under the title "Pickups and Hookup. by Our Readcrs" in RADIO !,-GE •. is T contributcd by our rcadcro. It is a dcpartment whereIn our readers exchange vIews on o:arlous. Clr· cuits and the con!truction and operation thereof. Many hmes our readers dIsagree on technical points. and it should be understood that RADIO AGE i. not respon.ible for the view. presented herein by con­ trIbutors. but publishes the letters and drawing. merely as a means of permittIng the fan. to know what the other fellow is doing and thinking.

F THE filaments of your vacuum tubes begin acting as you feel I during the Summer, it is not neces­ CONTRIBUTORS sarilyan indication that their span of life Name Address City has been bridged, for rejuvenation of R. S. Parks. ___ ...... _ ...... 1419 Cleveland Blvd.. __ .... _.. Caldwell, Idaho tubes seems to be as welcome to inani­ Clement Hampton .... _...... 427 Jeanne Mance St...... Montreal, Canada mate thoriated filaments as it is to those Walter E . Fee ...... _ ..._ ...... 115 Beecher SL ...... Atlanta, Ga. who have sought the fountain of eternal Carl Wininger...... _ ...... _.. . __ .. 20 William SL .. _...... St. Catharines, Can. I youth. Joseph A. Smith._ ...... 723 Wallace Ave .. _ ...... Wilkinsburg, Pa. Tube manufacture rs have cautioncd Francis Davis. . ___ _...... , ...... _...... _...... _Cushing, Okla. their customers, via the literature ac­ companying the tuhes in the cartons, DIAL 'TWISTERS that a paralyzed tube may be restored Albert C. McKee .... . , ...... 2306 Seminary Ave .. _._ ..... __ ._Chicago, Ill. to its pristine activity by leaving it P. French___ ...... _...... 1209 Franklin SL .. __...... Beaumont, TexasJ lighted in the set for ten min utes with A. RoberL_...... _. .... _ .... 327a Richmond St._ ...... _Montreal, Canada the " n" battery shut off, this process William Laning ...... _...... 325 North Bambry St. ___ ._Philadelphia, Pa. apparently bringing the thori um from the Alfred T. Chandler. ... _... _...... 280 Randol Ave...... San Jose, Calif. filament center and giving the tube ncw Charles H. Leach_. _. . __ ...... lOOO Van Buren St ... _...... __Chicago, Ill. lifc. James P _ Williamson ... _...... _327 Dorion St._.. __ ..... _...... _. . Montreal, Canada. One of our prominent m a nufacturers Warren King .. _...... 100 South Crest Road...... Chattanooga, Tenn. has comc forward with a tube- rcju ,'c­ Homer W _ Good ...... _...... _.. . R. F. D. l._ _._ ...... _. __Wescosville, Pa. nator on which radio fandom's interest H . Bowden._ ...... _.. ... _.. ... _. Box44,R. F. D.1, Mt.View.. Plainville, Conn_ seems to have centercc'. Mrs. Eva A. TayloT_...... _ ... _.69 Murdock St._...... Youngstown, Ohio I t consists primarily of a small step­ Fergus Mackay ...... Grange St ...... _ ...... Pictou, N. S., Can. down transformer, similar to the toy Kermit Fisher. .. _... _...... _...... 4335 Jacob St._ ...... Wheeling, W. Va. transformers used for running toy rail· Ackley T. Bush...... _...... 941 No. University Ave ...... Shawnee, Okla. road trains, etc., being made in two A. C. Taylor ...... _ ... .. Steele, N . Dakota types, one for 110-20 volt primary with Floid Omond ...... _. . 16 Alsace Ave_._...... __ Buffalo, N. Y . ten, four, sixteen a nd eight volt second­ D . C . Atkinson ...... _...... 788 Hohman St ...... Hammond. Ind. ary sections, and the other for the 220- C. C. Peugh..... _ ....._ ...... 54 Linden St.__ .... _...... _ ...... Schenectady, N. Y. 230 volt circuits with the same secondary K endall McNeiL_ ___...... __...... _...... _...... Ottawa, Canada outputs. This, together with a socket Jack Cordy. ___ ...... Box 25L ...... _ ...... __ .Globe, Arizona for each size of tubc,comprises thc layout, C. A. Hendrick ...... _ ...... Horizon Apts ...... _ .... Venice, Calif. to which the owner adds his timepiecc. George A. Moutsatson...... 265 Ohio St. __ ...... BentonHarbor,Mich. For the UV 199 tubes the tube is E. N . Girard ...... 715 South 58th SL ...... _.... . Philadelphia, Pa. placed in the socket after the tran~for~er Roy R. Winder...... __ ._ ...... _...... _._._...... _...... Pedro Miguel, Canal Zone has been plugged into the hghtmg Charles Markarian ...... _...... 110 Summer St. ___ ...... Worcester, Mass. mains. It is given ten volts on the fil a­ Lyle F. White...... _ .523 So. Washington SL ...... Kankakee, Ill. ment for 30 seconds, then the voltage A. L. Snow._ .. _._... _.. _...... ___ .619 Hendrie Blvd ...... _ Royal Oak, Mich. is cut to four volts and the tuhe is allowcd E. C. Kelley. __. _. . ___ . __ ...... _ ... __ ...... Underhill, Vt. to remain for tcn minutes. The firs t Earl Hamden, Jr--.-.-- ... -.. --.-...... _ ...... _ Globe, Ariz. voltage is k~o,\' n as the shocking charge John Hogle. __ ...... ____ • __... _ ... 321 Selma Ave. __ ...... Kenosha, Wis. and serves to drive the thorium from the Henry W. Werner, Jr_ ...... _.Box 419.... _...... _...... Valhalla, N. Y. filament center. The ten minute lighting W . Manning, Jr. ___.. __ ...... 619 Princess St. __ ...... Woodstock, Can, of the filament at four volts is known a s Robert B. Otto...... __ .85 Lowell St__ ...... _...... _... Mathuen, Mass. the bakin~ charge and serves to solidify Frank Barc1ay...... _ . .. R. M, D. 1.. ____. _. __ .... __ .. ___ ... Victoria, B. C., Can. the thorium On the filament so its elec · Edward Nolan._...... 657 Tenth Ave._. . _...... _ .... _ New York, N. Y . tronic emission is again at a maximum. Allan S. Wilson ...... 244 Kenwood Ave._...... -. Dayton, Ohio For the UV201-A type the shocking Harold W. Fairley._ ...... _._ ... 121 Gilmour Ave ..... _. __. .... _Toronto. Canada voltage is sixteen volts for a period of Robert W. BarnhiIL __ ._ ...... 1l6 East 9th Ave ____ .. _ ...... Bristow, Okla. 30 seconds, and a baking charge at eight Harold A. Reynolds ..... _ ...... 229 North Montello St. __ -__ Brockton, Mass. volts which lasts for ten minutes. The Wallace BuxtOIl. __ ...... _ ...... 4166 Emerald Ave__ ...... _ ... Oakland, Calif. same action takes place as with t he 199. George A. Winkle._ ...... ;... . 902 South 15th SL...... _Birmingham, Ala. J. A. Myers, Jr.._ ..... _ _...... _944 West Capitol St .. _... _ ... Jackson, Miss. One Need Remains M. E. Walter__ . _ _...... _. . _117 Lafayette SL .. _...... __ . ___ .Niles, Ohio \s a result the owner of emaciated Fred BruntoIl.__ _ ..... _.. _ ..... · .... _...... _ ... __ ...... _...... __ ...... Anaconda, Mont. tubes need no longer worry about a Cecil Carrigg ...... _._._ . __ ...... 215 21st Ave__ _ ...... _ ...... San FranCisco. Celif means of bringing back their life. How­ William Heinochowitz .... __ ... 135 Johnson Ave ...... Newark. N. J. ever, neither the tube manufacturers' George D. HillstroIlL __ ...... 10135 Lafayette Ave._ ...... Chicago, 111. method of restoring life by allowing the D. Gabelhouse._ ...... ___ ··· ____ ~·· _··. · _. _____ "-"'--'-" Vegreville, Alta., Canada tubes to remain lighted without the B battery on, nor the transformer method 44 RADIO AGE for July, 1925 The Magazine of the Hour Down with regeneration? No! Em­ phatically no! Let's keep it. but not abuse it. "This is merely a suggestion and many an old shoe will be shied at me, I'll venture, yet I hope it may stimulate others to give their views." The writer of the above, R. S. Parks, 1419 Cleveland Boulevard, Caldwell, Idaho, seems to put the case up not so much to this department but to fan­ dom, since it has been the policy of RADIO AGE to give its readers what they desire. If there has been a desire for DX lists, it is simply because the burden of the Editor's mail has been of that type. If the single tube regenera­ tive has been und uly touted in these columns, it is merely because so far the < ' majority of the contributors seem to have been most impressed with it. We realize there is a growing demand for the experimenter's section in this de­ partment, but so far the genus experi­ menter has not made his voice heard. Perhaps the publication of the above letter and the comment made wiIl serve ----~~I~(----~ ~ 1° to stir up interest. Perhaps it will lead to the creation of a band of experimen­ ters who have passed the one tube stage and wish eagerly for mOre experiences, although RADIO AGE cannot very well afford to forget the beginners who have many more problems than those who have already taken the dive into the pool of radio and have learned to swim. Henceforth, we will watch the mail very c~ref ully, and t he tenor of the de­ partment will be merely a reflection of the co ntributions received. It is up to readers An old reliable crystal circuit, one of th e early types used in the U . S. and still popular like ~lr. Parks to sound the call to arms with those who do not care for th e expense of a III be set for short distance reception on to his fellows; t hen let the station list headphones enthusiasts marshal their forces. May the better man win; we feel our readers mentioned before, will restOre a filament and Hookups Depart ment to be what it is will always wish us to abide by the de­ from which the spark of life has depa rted - no more, but personally I belie,-e that sires of the majority. due to a breakage. 'Nhen someone yOIl gaye this section of your magazine invents a filament restorer for hurned to the experimenter for a means of radio Old timers will readily recognize the out fil a ments he will he kissed on the de ,·eIopment. If so, then it is up to the circuit in Figure 1 as the ind uctively or brow by all the broadcast listeners, the contributor to use it a nd liS it wiuely. loose-coupled crystal set, with an arrange­ amateurs and the 0\\ ners of broadcasting ment for switching from the use of car­ stations, a lthough doubt less t he tube Dx Lists? borundum and a potentiometer to galena manufacturers \\-ould chase him into the .. DX lists do not OCCUTlY a seat of and other types of c rystal on which no wilds of Pat agonia with a sawed orf shot­ honor in my household simply because battery current is used. In the old days gun. I do not im'ite them, or to put it in the the carborund um was considered good At the last moment in our Jline issue words of an a mateur, 'I didn't get the because it \\ as fairly stable and rugged we were aille to get together interest ing Pacific Coast beca use I was not fishing.' and would stand the lurch of the ship data on the binocular and toroid coils To me the logging of numerOUs stations and the pound of the engincs at sea. which a re designed to eliminate the neces­ merely for a long list is a waste of time. It is sent in by Clement Hampton, sity for neut rali zation in radio freq uency Thc logging of t wenty-nine stations in so 427 Jeanne ~rance St., l\lontreal, Que., a mplifiers. The Pickups Editor will I,e many minutes as given by one of the Canada , who says his old friend, W. J. glad to hear from readers of RADIO contributors is la ughahle. ~r ay I ask Featherstone of 213 Ella St., Hull, East AGE as to the success encountered with how ma ny of us today would know any­ York, England, passed it on to him. these new ty pes of field less inductances. thing of radio and its possibilitics if thc The antenna variablc is a .001 and the Herc's a fan who is e,'cn willing that carly cxperi menters spent all their time secondary a .0005 mfd. The inductances shoes should bc shied at him, but he has at s uch fooli sh toying? Wouldn't it I,e can be either honeycombs, a loose coup­ the courage of hi s convictions a nd writes of more interest and of more educationa l ler, two spiderwebs, or almost any form us as follo ws: va luc if the contributors to this depart­ of good inductance. A fixed condenser " An intcrested obser\'er may he intim­ ment gave dis,ussions of different cir­ across the phones would do no particular idated many times before ma king his cuits, as ma ny are doing, effect of weath­ harm and might help a little. debut into a certain field; but. t here comes er conditions, code interference and most This circuit is popular in England a time when he Can restrain himself no of all , recei\'er interference? where no one is aUowed to use a regen era­ longer, and ma kes a headlong dash l,you will also notice that this section ti\'e set ca pa ble of feeding encrgy into the by giving his views on a subject . His contains hookups, nine-tenths of which antenna, and where the distances are not suggestions may be of little benefit and a re of the regenerative, onc-tube type. great, as is the case in the British Isles and then again they might open up a way for "Fine, I say, in the hands of one who continental Europe. something better. It is with the latter knows how to use them without spoiling in view I write this.' half a dozen neighbors' good natures. Known under seventeen or eightcen "Possibly yOU have meant the Pickups But how few of us there are who are ideal. differen t names, the circuit shown in RADIO AGE/or July, 1925 The Magazine of the Hour 45 Figure 2, and sent in by Walter E. Fee, of 115 Beecher St., Atlanta, Ga., is the single circuit Armstrong, noted (or its ability to squeal, and one of the oldest regenerative sets known to experimen­ ters. L 2 is inductively placed against L 1 for feedback. In Atlanta this circuit works out quite nicely (though we hardly dare think what the neighbors ha ve to say on this subject when the tube is oscillating). It tunes m the long distance stuff while WSB is batting out fii es, and for a change 1\'lr. Fee hooks it on a loop and goes fish ­ ing for distance, with results as follows : WSi\I B, \\'OC, WEAF, WCCO, KDKA, KSD, WOA Wand WQJ. Of course, this is used on head phones only. It is one of t-' the tried and true types of receivers, although not recommended for congested areas where your neighbor mig,)t have one too.

Here's another one familiar to the A fellows who ha ve been following the game' for longer than a couple of years. The 1------+1 1\1\ circuit sent in by Carl Wininger, 20 WilliamSt., St. Catherine's, Ont., Canada , 6 was originally published by ' \reagant 1 shortly after Armstrong gave the world '------''--1111111 1" J-!"-~-J his regeneratiye cir uit. Later \\"eag­ ant's circuit was taken up and popular­ ized by Reinartz, It has masqueraded under a thousand di ff erent names, but, the 'circuit fundamentally is the same T his is (he single circllit A rmstrong, L 2 is inductively cotlpled to L I for feedback pur­ poses, and its relationship is variable, The' inductance change in L I is by m eans of taps which is the point in which most experi. and the condenser in the antenna circ uit. Good for results but hard on 'Yollr neil', hbor If menters are interested. 'You let your tube oscillate Instead of using a variable regenerative coil for control of oscillation, the Weagant circuit, alias Reinartz, alias et aI, uses a variable capacity in series with an induc­ tance, the two paralleling the plate and filament. The control of oscillations seems easier with this type of receiver than \\ith the straight \ariable plate coil. The recei \'er shown in Fig, 3 happens to be the single circuit \Veaga nt, which can be made up with hone} combs, spid r­ webs, straight winding on a tube, or any other form of inductance. While it is good for excellent wcrk on distant stations, for the sake of other listeners it would be best to loose couple it, by having c an untuned primary in inductive relation to L l. The condensers in the circuit x shown are ,0005 m fd. Reinartz found that oscillations could be better con trolled ~ by inserting a small choke in series wi th the phone lead at the point marked X L-' in the diagram. 1- In the inductiYCly coupled receiver the ~ 8- condenser C I spans LI, wh ile the an­ tenna comes down through a fifteen turn coil to ground, The secondarry is then removed from direct contact with the L .... aerial and if the receiver does fe ed back C into the aerial it will be \\'ith lessened energy. Ll can be approximately fifty to seven­ ) t-- ty-five turns, while L2 can be somewhere bet\\'een thirty·five and fifty turns, the - " condenser C2 making it unnecessary for the exact number of turns to be found for the inductance L2. Another form of the Armstrong re­ , Another popular type of receiver in which regeneratil'e control is by a variable capacity generative is sent in by Joseph A. Smith, in series with an inductance paralleling the plate and filament. Known years ago a. 723 Wallace Ave., Wilkinsburg, Pa., who the Weagant circuit, later populariud by Reinartz and others. Better build it loos.! tells of the good work it has done for coupledjor the sake of the neighbors, unless Y0tl happen to lil'e out in the exact geographict. l him. He says it is good away from con- center of the Gobi desert 46 RADIO AGE for July, 1925 The Magazine of the Hour gested districts. His coils are wound as follows: L2 52 turns 18 or 20 DSC on a three or three and a half inch form. Around center of winding one layer three quarters inch cambric. Stick 8 pieces of hard rubber 3-4 by 3-16 by 1-4 placed equidistant around the piece of cambric, fastened with collodion. Coil L1 is wound on these blocks and consists of 3 to 10 turns of the same wire. An ordi­ nary plate variometer is used for L3. C1 is .0005 and C2 .001 mfd. This cir­ c' cuit is inductive and even if oscillating would not cause the same amount of annoyance which a single circuit would. He submits a list of DX stuff that cer­ tainly entitles him to the DT button.

Another circuit which has proved very popular with those who wished to econo­ mize on tubes and material, is the reflex circuit, originally attributed to Latour, the Frenchman, who gave it to the Allied communication authorities during the An inductively coupled Armstrong regenerative. Coils Ll and LZ are wound by the con­ early part of the war and which was tributor. while L3 is an ordinary plate variometer. He gets good results on it, as he slwuld with a loose coupled regenerative set. immediately pounced upon by everyone on this side of the water as an excellent feininine fans, the first from 'Floid received on a manufactured four tube circuit from an economical standpoint. Omond, 16 Alsace Ave., Buffalo, N. Y., set with built in loud-speaker. She It has been rearranged countless times who finds RADIO AGE interesting in wonders if there is anybody in Chicago and additions and deletions made to the every way, and specially the Pickups who does not own a broadcasting sta­ original. and Hookups. She has built a one tion, as her experience on the air seems This circuit, Fig. V, is sent in by Fran­ tube and a three tube set and has re­ to show that nearly everybody in Chi­ cis Davis of Cushing, Okla., who tells us ceived fine DX stuff with these. So cago is broadcasting. Ll is wound on a 3 inch tube with 15 we will send her a button, but regret turns of No. 22; L2 same size tube with we haven't a little wisp of ribbon to 50 turn s; L3 is the same as L 1 and L4 send along with it; we used up the last We got quite a laugh out of a letter is the same as L3. The variables C l piece in winding a coil. from Albert C. McKee, 2306 Seminary and C2 are .0005 mfd. C3 is .00025 and Ave., Chicago, 111., who says his set is C4 is .001 mfd. The other feminine ether chaser is in a second edition of "Hell's Kitchen" Davis' list of DX stations also gets Mrs. E va A. Ta ylor, 69 Murdock St., where he has to contend wi th regenera­ him the DT button. Youngstown, Ohio, ' who reads RADIO tive squeals and howls. In his letter AGE with a great deal of interest, espe­ he tells of making a crystal detector Looks like the ladies are not to be cially since she ran across one of the out of an old mouse trap but fails to prevented from having equal rights in Youngstown ia n names in the magazine. tell whether he was bothered with radio as well as economics, for in this She has qualified for the button by squeaks on account of this fact. He week's mail come two letters from sending in a list of stations she has (Turn to page 48)

Another popular circuit, the reflex which sprang from Latour, the Frenchman, during the war. It is simple, effective and economi­ cal. What more can the fan ask? This one was sent in by Francis Davis, of Cushing. Okla. RAD IO AGE for July, 1925 The Magazine of tlte H our 47

Offers to Its R eaders the First Feature of Its Kind Ever Publislle(i [n a Radio M agazine A Round.. up of Hook.. ups ALL Basic Circuits from which ALL Radio Hook-ups are Developed Described and Illustrated \vith 62 .. Page Blueprint Section

OR the fIrst time in any HIS unusual number will In the [, F radio magazine, RADIO T sci I for the usual price of I AGE is publishing in its 25c a copy. Of the pages August, 1925, issue, an array "De Luxe" 1n this number, fully 56 will of radio hookups that will contain actual const WCI ional impress and delight every August Issue articles, of which THIRTY lover of technical radio infor­ OR MORE pages will be typi­ mation and accuracy. of RADIO AGE, cal RADIO AGE blueprints, In this big number, which which have made the " Maga­ is to be our "Deluxe August zine of the H o ur" distinctively issue," RADIO AGE will Out July 15 famous the world over. prove its superiority in the From the simplest crystal technical field by giving its readers, at no additional set, the articles in this number will ena ble the reader to travel by an orderly process to the super-hete rodyne, cost for the magazine, many pages of hookups, from the taking in every popular t ype of receiver introduced early diagrams to the very latest developments ' in since the advent of the radio science. multi-tube design. Where improvements have been made, the latest technical explanations will be gi ven. Everything will Because o f thc inevitable popularity of this number, be strictly up-to-the-minute, and written so clearly and the dcmand its publication will cause, readers are and Simply that either the rawest novice or the most seasoned technical expert will understand the articles asked to order copies in advance. almost at u glance. Order Your Copy of This Wonder Issue In Advance!

25 CENTS A COPY, RADIO AGE I 500N. DEARBORNST. , $2.50 A YEAR , n e. , CH ICAGO 48 RADIO AGE for July, 1925 The Magazine of the Hour about fifty turns of No. 18 bell wire (also known as annunciator wire), span­ fI ,~ ning it with one of the Remler con­ "THf\T IS densers he uses. Insert in series with the aerial lead of your normal primary THEWAY H'E: and tune to Zion's wa,-e, leaving it TALI( S 1 there while you chase off in quest of N E E- DN' , other signals. GO 'N AI Roy R. Winder, Pedro l\Iiguel, Canai A LL' Zone, sends word of his luck with radio in the land of static down around "Pete­ l\Iike" on the Panama Canal. The first station he has a chance to pick up is P\\,X, Ha"ana, about 900 miles to the northward. He is a regular reader of RADIO AGE, considering it one of the most "aluable assets of radio.

Another fourteen-year-old radio fan is E. X . Girard, i15 South 58th St., Philadelphia, Pa., who uses RADIO AGE hookups as his guide. He gets out of town stuff without trouble from t he locals and sends in a dandy OX list.

Kendall :'.IcXeil, of Ottawa, who neglects to send his address, writes interestingly of his excellent results with the impro"ed three tube Reinartz described in the May RADIO AGE b y l\l r. Piety. He gets all the stations in the U. S. and also nabbed two or three of the Continentals, namely Lon­ don, Newcastle and Aberdeen, all of which he has confirmed.

(From page 46) did help his set to such an exten t that D. C. Atkinson, 788 Hohman St., thinks J. B. Rathbun, who makes up he logged quit e a batch of OX stuff, Hammond. Ind., one day used his the blueprints for the "arious hook-ups for which he is hereby awarded the downspout on the eave-troughs of the appearing in R.\DIO AGE, is to be D. T . emblem. house instead of an antenna, getting complimented on their uniform accuracy stronger signals. He used this on a and efficiencr. He is using a five tube George D. Hillstrom, 10135 Lafayette crystal set, but says he has not tried reflexed radio frequency set recently A,·e., Chicago, Ill" is a 14 year old it on a tube set yet. Let's hope his described by Rathbun and gets won­ youngster who is following RADIO experience will not start an epidemic derful results with it. His list of sta­ AGE circuits with great success. His of down-spouting or else all the land­ tions entitles him to the button all right. letter conta ining a OX list ent itles him lords in the country will be faced with to one of t he co,'eted buttons. the necessity of installing tinned copper A. C. Taylor, Steele, ~orth Dakota, downspouts with binding post con­ says he finds there is no other publica­ George A. Winkler, 902 South 15th nections for each experimenter. Many tion that deals with radio that has such St.. Birmingha m, _)d a ba ma, want s RA­ tin roofs ha,'e worked better t han a a vast amount of good reading matter DIO AGE t o keep on pouring it into poor antenna, but always remember as RADIO AGE has. He says he was a certain radio octopus with which there is NO substitute for a GOOD surprised to see the circuit used by we are ail acquainted. He sends in a antenna. E. H . Jones in the April number, and diagram of a n eight tube super which feels that too much cannot be said for he is using \\-it h good results. such a circuit. C harles :\iarkarian, 110 Summer St., How are P. E. Chapman, 805 North Preston \Vorcester, Mass., gets fin e results with St., West Philadelphia, Pa., thinks t he reflexed neutrodyne described by Your DX Lists RADIO AGE is the best on the market Mr. Hopkins in the January issue of and reads it with great interest. He RADIO AGE. Coming This thinks our indtation to readers alld experimenters to forward their results T. L. Kent, i21 :'forth A'-e., Wau­ Summer? with new circuits is certainly a boost kegan, II!., formerly 6US, is now ou t to the amateur and a great help t o all of the "ham" and int o t he BC L game, who are interested in radio. He is still which he likes very much. Let the using the four-tube -circuit published by R.-\DIO AGE in September, 192-4, John Hogle, of 321 Selma Ave., "Pickups and and with it has logged 16; stations; Kenosha, Wis., says he is bothered by three Europeans, two Cubans, fi'-e only one station, that being Zion. He Hookups" Canadians, six Pacific coast and one asks for a wave trap that will obliterate Alaskan that station. He has made up his Readers set from R:\DIO :\GE blueprints. He P. French, 1209 Franklin St., Beau­ gets excellent results from his three mont, Texas, took us at our word as to circuit regenerative. A wave trap might Know About Spring cleaning referred to in the May be used on Zion with -good results. Make RADIO AGE. He reports that Spring it on a cardboard form a bout three T hemt cleaning from aerial to ground cla mps inches in diameter, \\inding it witn RADIO AGE for July, 1925 The Magazine of the Hour 49

DAVEN SUPER AMPLIFIER It is a recognized fact, that only a Resistnnce Coupl('d Amplifier deliyers perfect nmplification. " -itb the SCPEH. A)fPLIFIER YOIl are assul"eo of ampl.. \·olume, lowel' "B" Battery consumption, minimum of assembly lahor, unimpeachahle quality-an amplifier which makes any good set hetter,

9',6P J;17P !!/A!(.ri( Obta in from vour \~ ;A\Y EIW(\g~ \~fi\g ~/O R '1J'{)'ID~!i\ I/ (}~( Dealer the ne~iM­ Amplir. .. r I .. it .. tor ~1"n .. "1 a com­ In 3 or 4 stagrs plete handbook on "~(>sLdor .J;,ec/o/tstJ-" for those who ResIstanc e NEWARK N.J. W 0 u I d rathel' Coupled Amplifi­ build than buy cation. Price 25 the completely cents or postpaid TRAOE MARK REG. U. S . PAT. OFF. ass embled I 35 cents. Sup e r Ampli­ I "fler.

Sales Distributor Wanted * to start now in the fastest growing business the world ever knew-Three Million radio sets were sold last year- 22 Million will be sold in the The Difference­ U.S. A. When Using AMPERITE THE AMPERITE the "self-ad­ justing rheostat", automatically con­ MUSIC BOX trols the flow of current, and makes hand controlled rheostats obsolete. RADIO Permits the use of any type of tubes or any combination of tubes. RECEIVER Specified in every popular Con­ struction set. is the peerless seller of them For perfect results you must use all. Think! Only two orders to AMPERITE for filament control. weekly means $600 per month. Price $1.10 everywhere. Four orders $1200 per month. 1 RADIALL COMPANY Anoth~r important d."elopm.ent in ACCURATUNE The Set with the Marvelous conatruc:tion- the u.~ of a full bra •• 8'@ar train. built Depl. R.A.-7. 50 Franklin Street. New York City exceptionally rugced and de'.i~".d for Accurate Tunine. Tone and Volume Supreme. " Ab.Qlutely elsenllal for sensitive .et .... I . Friction Clutch. 2. Lo". Center Ruthinlll_ 3. Ne'w Cear Write for the Distance getter of them ' M e'sh. At your deale .... otherwi •••end price (S3.S0) FREE all. Write now, today, for and you Will be lupphl'td. po.t.tpai.d OUr liberal IS·day trial offer MYDAR RADIO CO., , ·K c..mpb.1I 51 .• New.rI.. N. J. and protected territory. THIELEN, Manufacturer ACCURATUNE 1207 North Shore Ave., Chicago, JUG.~r~.~D OJ,··i."! us AI4".~" MICROMETER CONTROLS

"The Roundup 0 f Hookups r' -112 pages 0 f e\'ery concei vable kind 0 f rad io hookups-wi II be the big f eatureo f the "Deluxe" Edition of the August RADIO AGE. On t he stands July 15, but order your copy in advance if you want to get this wonder issue. More than thirty pages of blueprints and scores of hookups! 25 cents a copy. ¥- Tested a.nd A pproved 1m RADIO AGE . ¥- so RADIO AGE for July, 1925 The Magazine of the Hour The Broadcast of Plays for the listener-in a VISion of the layout How Much Coupling is concerning which he hears the spoken Written for Radio version. In the movie, the audience sees Necessary? By E. E. Mattson but does not hear. In the radio, it hears (Continued from page J.I) Westinghouse K Y W and will see hy virtue of the impression INCE the advent of radio, its progress In making the final primary coil, it is that will be given the listener by the best to allow taps at two or three turns S has brought many improvements, personnel of the act. some of them expected and some not more than necessary on long waves and It is the purpose of Station K Y W to at least two less than necessary to pro­ looked for. However, improvements from give life to this plan. Mr. Wetherbee will a technical point of view have not been duce oscillations on short waves. This supervise the writing of plays to be used makes sufficient allowance for depreciat­ the only goal sought in radio. From the over K Y W. He has completed the first beginning radio was popular because of ing tubes and batteries. one act play, "The Fates Decide" which The variable coupler makes up for its newness, its mysteries and seeming will soon be put on the ether. In this intangibility. A person bit by the radio lots of little differences in sets, such as play he employs three people, Norman aerials of different capacities, tubes of bug soon became almost diabolical in his Landon, a wealthy newspaper owner, I ust to grope into the distance, and spared more or less oscillatory tendencies, Marion Landon, his wife, and Franklin batteries differing in voltage, detectors no effort to purchase or build a set that Ames, his life long friend. The entire brought him clear and distinct reception. of more or less absorbing powers and the plot is laid out with the same care and like. It avoids the necessity for variable Those were fascinations that led him on. thought as given a play for the stage. It With the advance of radio activity, and feed-back coils like reversed ticklers, for will be acted by three artists of the sta­ inducing regeneration on some wave­ the many angles taught its leaders by tion, who have been coached in rehearsal experience and study, it became apparent lengths a nd counter-acting it on others. until the effect intended has been brought And it permits long wave stations to that the mere broadcasting of vocal or out to a high degree. instrumental numbers accompanied by come in as well as others; in fact, it makes conventional announcinlr would not suf­ reception uniform all over the dial's fice. The rendition was heard well but it scale. appeared automatic, it lacked the per­ Summer Radio Conditions sonality that would make it pleasing and To Be Surveyed Phonograph Stores Are beautiful. The artist was taught to im­ FRANK Hopkins and Harvey T. Handling Radio press the invisible listener-in by sound, Kelley, Assoc., I . R . E., and well what the stage artist did by pantomime. H • known radio engineers, plan to EW YORK-Radio parts are now The announcer was given the idea of leave Chicago some time during August N being handled by phonograph stores making his remarks fit the occasion and on an extended trip throughout the West­ throughout the country and on a grow­ blending them into the program as ern and Southwestern portion of the ing scale, declared Ben Aplin, eastern sales manager for the Shaw Insulator part of it, thereby assisting the proper United States, to carryon an intensive survey of broadcasting conditions in so­ Co., of Irvington-Newark, N. J. Mr. balancing of the act. These, and many called "dead spots." Aplin, who is one of the best known other things were essential. Beca use radio reception is so difficult salesmanagers for molded radio materials After about four years of radio activity, in the Summer-time, under most condi­ in this country, has been deeply im­ numerous ideas have presented them­ tions, the two experts will endeavor to pressed by the increasing vol ume of selves to radio directors, visualizing the trace the causes and record them for sales being recorded by phonograph and need of a change of venue. \Vilson public use. Their findings will be sent music stores for small parts which hold Wetherbee, director of Westinghouse for publication in RADIO AGE as the such an important part in the radio trip progresses. - industry. Station K Y W, has long felt this need A 100-watt broadcasting station will "Hundreds of dealers throughout the and for some time past has been active in be part of the equipment carried on this eastern section of the country who coaching the personnel of K Y W toward trip, and arrangements have been made previously handled musical instruments this goal. Radio broadcasting demands to carryon tests in Colorado, Utah, and records, and eventually added radio new things, and it will get it. The movie Arizona, New Mexico, Southern Cali­ sets have been finding that small parts industry started with one-reel features, fornia, a nd where static conditions at have been inval uable sources of profit and during its evolution it grew until this time of the year are un usual. Under to their sales total. today the cinema features full plays these extremely adverse conditions, an "This fact is more apparent .as one, attempt will he made to determine just in travelling throughout the greater brought out with a studied skill, wherein what kind of radio circuit performs the cities, finds that dealers everywhere are the personality of the actresses and actor~, best. Several circuits will be taken on' adding small parts as the direct results aided by elaborate stage settings, convey the trip and test cd under varying of demands made upon them by their to the audience the same impressions that atmospheric and geographic conditions. trade. There are al ways some parts of the spoken drama would. The success of Communication with Eastern and their set which they desire to replace the movie is evident by its popularity Pacific broadcasting stations will be to add greatly to the efficiency of their among all classes, the highly educated maintained throughout the long trek, sets. and those less favored. which will be made by automobile. "With that idea in mind they go to Several stations have expressed a desire the music store which sold them the set A Radio Technique to broadcast the findings of the experts, and insist upon buying some particular Mr. Wetherbee's ideas have brought to guide them in reaching districts and part. If the dealer does not carry that listeners in isolated parts of the world part or for that matter any part in stock out that radio thirsts for something more who at present encounter difficulties the customer goes elsewhere. The than "one reelers." His experience has in maintaining consistent touch with natural result is that the dealer, rather taught him a technique of radio more radio stations throughout the year, and than see business going to another store, than the mere announcing of a selection especially in the Summer-time. grad ually stocks up new and small ann then putting it over clear and dis­ Mr. Hopkins and Mr. Kelley intend to parts which he finds hold ready sales tinct. The announcer, the artists, the devise several new t ypes of radio appa­ appeal to his customer. stage setting- a ll are unseen by the ratus to meet the di ffi culties they expect II Many dealers were first of the oelief listener. The general atmosphere has to will confront them. These varied types that the carrying of small parts would of apparatus, which will be designed be impressed upon the listener by sound, be the means of cI uttering up their after thorough tests, will be described to stock. Instead they are gradually finding and by the personality injected into the readers of RADIO AGE this Fall, that by simplifying the arrangement microphone in the studio. So far this thereby being of great value to those of their merchandise they are able to policy has succeeded admirably. Now fans who live far from strong stations fill the customers, demands at once. Mr. Wetherbee's plans bring forth radio's and who are bothered by static, fading "I t is no longer necessary to spread demand of short acts, in which several and other unaccountable disturbances. Both Mr. Hopkins and Mr. Kelley these small parts in every section of the persons take part, and in which the store. They are now systematizing scenes are laid with the same care and have long been identified in radio circles, having done much research and their stocks of these small radio parts aforethought as on the stage or in a dev.elopment work. Both are past with the result that a show case or two photo-studio. \Vith radio, however, masters in the transmitting and receiving in a particular section of the store carries technique finds employment in drawing art. the stock req uired. RADIO AGE for July, 1925 The M agazine of the Ho ur 51 The Radio Spies (Conti1tued from page 32) occasions seen this same Cecelia Lambert at the De Forest plant in jersey City. 1 was likewise told by another employe who was working under Harley. whose name 1 do not recall. that there was at that time another investigator stationed at the De Forest plant who was known as ·E-I0.' .. After saying that he arranged for Thies to procure certain information concerning the complainant. BO"'lby declares he passed on Thies's written report to Harley. adding. "this report conL1.ined. among other thincs. a description of all the machinery used in the tube department of the De Forest Radio Company while he.was work.ing ther;. as far a s he cou ld remember t he same. together WIth the method of o perating these machines; also the infonnati~n regarding filament wire used by tha~ company tn making its tubes and where they obtained the same." . Bernice M. jennincs. employed as typ1st by the Radio Corporation of America from November. 1924. to April. 1925. said an employment agency sent her to Room 301. 25 Beaver Street. where she a.sked for Mr. Harley. She was engaged by a Mr. Silverton. There were six girls under Mr. Harley in Rooms 301 and 302. she says. Harley's private. office was Room 303. She alleges that Room 217 1n the same building was also occupi~d by a girl under Harley's direction and was also used by Radio Corporation·s . investigators. Through the Locals'--­ Instructed on Secrecy Soon aft<>r she began work. alleges Miss lennings. she was told by several other employes in the office not to give out any information regarding the people ALL.,AMAX Reaches Out in the three rooms. or their business; anel a lso not to let anybody know that there was any connection between the employes there and the Radio Corpora· Every ALL .. AMAX Set, wherever it may be, brings to tion of America. Two weeks laler she was trans' its owner his choice of all the beauties in the air. ferred to Room 217. Once a man dropped in and asked for Mr. Harley. S he directed him to Room Every day come more and more letters to our office. 301. When Harley heard of the incident he is alleged to have said to Miss jennincs. " In the future. if telling of the long distance reception, almost unbeliev .. a nyone comes here and asks for me. you don't know able on a three .. tube set, . which has rewarded the me nor anything about me. and nO one here has anything to do "ith any radio business whatever." owners of ALL" AMAX. H arley. the affidavit continues. received ",'litten reports from many investigators. They were usually Remember, too, thatALL.. AMAx is completely mounted stamped "ith Harley's initials and then ,,'ent to Silverton, who stamDCd them with his designation. on panel and baseboard. You can wire it in one delightful " C ~ .. ~en she first began copying the reports. says evening, following simple photographic instructions. M iss j ennings in her affidavit. they were headed ;:'y ALL-AMAX SENIOR. three tubes and detector • . Price. S4Z.00 the name of the person or Concern under investi· ALL·AMAX JUNIO;;;:. cne tube and detector . , • • Price. SZZ.OO !:ation. For three months prior to April 10. 1925. she received almost daily reports from "C·3." Cecilia Lambert. reports headed "In re De Forest." ALL~AMERICAN RADIO CORPORATION but subsequently the heading was changed to "381" E. N. RAULAND. President and that number was give n to the file which contain· ed matters relating to the De Forest Company. . 2680 Coyne Street ~ Chicago The reports covered many thincs. the affidavit a llege•. including the tima employes began and Quit work. "whether there were few or many employes at work. whether they worked overtime or less than full time, whether business was brisk or slow, what e mployes were discharged and what new ones were taken on. the names and addresses of employes. so ALL-AMERICAN far as she was able to give them: instrucuons issued to foremen and persons in charge. notices posted in Institute Correction t he departments governing the 'personnel of superin· tendents a nd foremen. why a foreman had been laiel Through a n off. efforts roade to speed up production. and espe­ error, the ill us· cially what took place in the power tube depart­ trationsof Tests ment: on two or three occasions her reports contained No. 47 and 49 attempted drawings of machines used in the depart· in t he RADIO ment in "'hich she was working." AGE Institute EARN Sev eral times Miss Lambert. it was alleged. sent for May, 1925, $50 to $200 a Week in with her report some pieces of filament wire. and 5ead for mY big FREE RADIO nOOK ght oowl See bow m.&.n, .ondf"rlol mon~Y male OpC)Cr· she also sent in what she designated as "gold seals." were reversed. tuDitles lU'e waillng' for YQ" a s a TJ'ai.n E :'tPc rt 10 the Uvest, b .stcst gJ"OWl.Qg Big JiI'ar' field ~ used in cormection with the manufacture of power T he Quam Con­ the wotld-RADIOI tubes. denser test was Corroborates Bowlby ill ustrated by William Buckbee. a tester in the De Forest Labo· an engraving of ratory. swean< in an affidavit that in company ,,;th a the Duplex young lady he met Harley. at the latter's sugges. _ Condenser, and tion. With Harley was Miss johnson, whom Buck­ vice versa. bee says he knew to be a De Forest employe. Harley, We are reprint. Buckbee asserts. told him that Miss johnson was ing yiewsof the two an investigator for the Radio Corpora tion and that COn den sers wit h she was one of five or six employed in t he De Forest plant who were also employed b y the defendant. their pl'oper identi· "At that interview." the affidavit continues. ficat ions. The top Your Radio "Harley offered the young lady accompanying me a dew herewith position as confidential investigator for the Radio shows the Quam Corporation of America and stated to her that as condenser, and the such confidential investigator he could get her a cut at the bottom position with the De Forest Radio Company. as i s a Duple x stenographer. and that he wanted her. after having 1\1 atched Con den- (Turn to page 60) seL :(. Tested and Approved by nADIO AG E 'f. 52 RAQJO AGE for July, 1925 The JJagazine of the H oltr. Standard R adio R ece i ve r s

R ecenll y R A D IO ACE inaugurated a neW department called I , K now B ejore You Buy," to serve as a guide to the prospective radio purchaser in deciding On the receiver best suited to his individual needs. Fans throughout the country have shown an instantaneous response to this new jeature, and accordingly it is continued and will be a jeature oj all jorthcoming numbers oj RADIO ACE. Readers are invited Lo write us concerning the sets in 'which Ihey are interested, and manufacturers also are asked to send us material describing their sets

Selectivity Paramount in Chelsea Sets rrHE Chelsea Three an(1 Fi .... e T ube receivers have he en designed with .... irtually one end in \'iew: that of attain­ ing ·the ultimate in selectivity. The Chelsea Super Five, just annOunC­ ed, is a fi \'e tuhe receiver embodying this select i \'ity with unusual ,,01 ume. Dis­ tortion is minimized so it is,unnoticeable, as is any annoying squealing. The Chelsea Fi\'e has all the principles of the perfected non-regenerative set, including remarkable distance. The cahinet, of the sloping type, is finished The Chelsea in rich mahogany with shielded Bakelite. T he retail price is now $50. step of tune(1 radio frequency ampli­ The Three Tube Chelsea "Tone Modulator" in fication, .... a cuum t ube detector and two Clear 'I,'olume on the loud speaker, with steps of audio amplification. The fi rst Resas Receiver ability to bring in distant stat ions wit hin tube is reflexed ; that is, it amplifies radio H E perfected Resas T one-A-Dyne reasonable rang:! , is the feature of the and audio frequency at the same t ime; T recei"er emhodies every advantageous Three-Tube Chelsea. :\olodel 12 2. This ma king the Eaglet v irt ua ll y a four tuhe feature claimed for any fi\'e t ube set , set has been on the market for some time recei'l,'er. plus the Tone Modulator, a feature and has gained a reputation for its con­ It gi" es reception equivalent to a four t hat is to be had only wit h the TONE­ sistently remarkable perf?rmance . . O~e tube clry cell set, using only the current A-DYNE. station is received at a time, proving It required by three tubes. The E aglet is As its name implies, the T o ne l\lodu­ is also sclecti\'e. porta ble in the sense t hat it is light of la tor controls the tone and " olume at The Chelsea 3-Tube Set is of the triple weight, ca n be conveniently ca rried a ll t imes a nd under all operat ing con­ ci rcuit type, controlled by a single tuner. a bout the house and can be hooked up ditions. T here is nothing complicated No knowledge of radio is necessary to t o d ifferent antennas. taken out in an or di ffi cult about it. Simply a t urn of operate this simple receiver. T he cabinet a uto, used on camping trips. Summer is slightly sloping, as in the Chelsea homes and hospitals. Super Five. It is of attracth'e finish. For its operation it requires t hree The price is nOw S.J.O.OO. ~o. 6 dry cell A batteries 1 H volt, a nd four ~ o. 23 ~ B intermediate size or The Eaglet Receiver a "Prince One 4~ volt unit C . T he t ubes arc U V 199 vacuu m tubes or their equi .... a­ of the Air" lent. The instrument can be operate::! H E EAGLET , a three t.~be. dry c~l1 with ear phones or loud speaker. T he T neutrodyne, has been weighed In installation is t he same as the Eagle the balance" of engineer's tests, and has model B ; namely , approximately 100 the knoh and the musical or v oc'a I selec­ pro\'ed that it possesses selectivity, feet antenna. T ,,'o antenna leads a re t ion assumes its most pleasant volume . provided, one for long and One for short ' The Tone-A-Dy ne is non-radiating. aerial. Annoyance from squeals and howls is The receiver is a delicate, scientific eliminated. The selectivity of the T one-A-Dy ne instrument, and should not b e tampered is unusually satisfactory. With loca l with by inexperienced people.. The stations broadcasting on a wa velength Eaglet has been welcomed both by the only 5 meters away, station \\' HAS trade a nd the conSumers and has already (Louisville) has been readily tuned in endeared itself to thousands of owners. without interference on a short indoor Families spending the hot months in aerial. camp5, mountains, or sea shore will finrl The Tone-A-Dyne is so designed that the Eaglet a SOurce of great joy a nd w'i ll it can be operated by anyo ne wit hout be able to keep in touch with the wonder­ pre\'ious experience. The three tu ning ful open air orchestra progra ms that are dials are accurately calibrated and matc hed so that their settings p ractically ah\'a~ s broadcast during vacation time volume as well as simplicity, distance correspond. There is only one filament from the country's Le;!t stat ions. The and t one \'olume. These qualities, control, and this can be set at the best coupled with good workmanship, finish wa ter e nt husiast ca n listen in and have operating point on reception of the first and guarantee, constitute the last word a whale of a time \\'ith his E aglet installed station. A snap switch co ntrols all in radio. on yacht or motor boat, on account of t ubes. Clearly marked binding posts are The Eaglet embodies t he Eagle Bal­ its compact design an d light weight. prov ided in t he rear for all COn nections. anced Neutrodyne circuit, using One The price is $75.00. The price is. $78.00. ( Turn Lo page 54) RADIO AGE for July, 1925 The Magazine of the Hou'y 5J Learning the Various Tube Characteristics (Continued/rom page 12) operation. This condition usually comes suddenly; it is not spread out over the The "Better Tuning" Control life of the tube as would be expected. It is sometimes caused by applying excessive voltage to the filament of an otherwise good tube. If such is the case, it is possible to restore the tube to normal A New B-T Product by the rejuvenation process, or by apply­ ing the rated voltage to the filament with the plate voltage cut off, for about Hairline Control, Easy Action, a half hour. From the above it will be secn how Simple Mounting. an old or defective tube will cause the * aging of the oj:her tubes in a circuit. No side strain or pull on shaft to This condition is readily noted by the necessity of increased " A" battery wear out bearings or destroy voltage-but most fans just turn the rheostats on and let it go at that­ alignment of your cot:ldenser or paralyzing or otherwise decreasing the coil. efficiency of all of the tubes, which is a rather expensive performance in the end. Reads 0 to 100 or 100 to O,-set· Amplification Factor tling the argument as to "clock­ o DETER M INE the amplification Tfactor of a vacuum tube experiment­ wise" or "anti-clockwise" instru­ ally, a high frequency current of about ments. 1,000 cycles is necessary-along with a hot wire galvanometer and other asso­ ciated equipment. However, it is pos­ Registers dial numbers, wave sible to determine this factor by use of lengths, or call letters. the plate current values of the tube under $2.50 test, substituting approximate values for functions of the various voltages in the Exclusive features fully protected Improves the tuning as wen as tube. Thus,-I -a Eb E .. E) 2 in ('1 + + by patents pending. appearance of any set. which I equals the Thermionic' current in milliamperes, E!, equals the potential (voltage) difference between the plate and filamen t, Eo eq uals the potentia l (voltage) The new Tuning Control is distinctively a B-T product. It is of of the grid and E is an arbitrary quantity the same sensible design and careful construction that has charac­ representing the small differences of potential (voltage) existing in the tube terized radio parts bearing the B-T name. under various conditions. a is a struc­ tural constant. The quantity '1 in this equasion is as You should know about the new B-T socket. Send your name explained in volume 47-1918-"Physical and address for circulars on this and other new B-T developments. Review" by Van oer Rijl-"That for equivalent values of E!, and E e , a change in the cinode (plate) voltage Eb produces '1 times as great a change in the curren t to the cinode as an equal change in the grid voltage Ec"-or non-technically-a BREMER-TULLY MFG. CO. change in voltage on the plate would have to be '1 times the voltage change on the grid that would be required to 532 S. Canal St., Chicago produce a given change in the plate cur­ rent. The voltage amplification factor p. is the reciprocal of this quantity or ",='/'1' This is shown graphically in figure 2- 50 Get this great new where the grid and plate cun'es are drawn $3. Volume with to the same scale on the same chart, indi­ CLEARNESS i. obtained by uaing MAP THE AIR cating that a much smaller change in of FLINT AUDIO A MARVELOUS new way to chart your radio grid voltage will produce a greater change Frequency Trcrns/oTtnerS exploits- a beautiful Air Map, printed in three in plate current than a like change in colors w ith every station clearly marked and W. will sypply if YOy, d.. lu tanno' T ime zones out lined! Size 28,,34 inches, plate voltage will produce. FLINT RADIO CO. There's no limit to the useful and amusing ways 1884 \Vilson Ave. Chica~o you can use Collier's new Radio Map of the U. S . The ratio of the two voltages required and Canada. With its help-- to produce a gi ven change in plate current is the amplification factor (u2) on the You can find out INSTANTLY chart; the ratio of the slopes of the straight how far any s ta tion is portions of these curves is the amplifica­ If you use a d irectional aerial. you can point the loop tion factor. exactly toward the station you want to get. The 514 PAGEs-Grea""'l book OD KaLlio map also outlines t he radio districts and gives an The amplification factor of the tube e yer .,-riUeq. New_utboribtive­ alphabetical list of all stations and their operators. plotted on this chart will be between 6 complete. Packed witb r;o u Dd. p ract,cal Thousands have already been sold. Get yours information useful to everY rad io fan . today! At your news-stand or radio dealer's, only and 6.25 or an average of 6.125. With Hundred . 01 illu."t rations. Send 81 twenty-five cents--or just mail a quarter to u •. t.oday. Mon~y bac:k if Do t aati!fi ed. this average factor we have '1=1/6125 International COlTeapondence P . F. COLLIER & SON COMPANY School •. BOJl8783-D, Scranton, Penna. (T1trn to page 56) 256 Park Avenue New York City ~ Tested and Approved by RADIO AGE ~ 54 RADIO AGE for July, 1925 The Magazine of the Hour Standard Radio Receivers; LIFE, The Atwater Kent LIBERTY (Continuedjrom page 52) and the Pursuit of HAPPINESS!

..... Atwater Kent Carefully Atwater ~ent Receivin~ Sets overcome these difficulties to a marked degree, Designed so that two or more stations broadcasting IlE careful construction of Atwater at the same time can be separated and T Kent Radio is apparent to the most the desired station tuned in clearly and casual observer-the easy movement of without troublesome interference. the tuning dials; the absence of intricate One of the most pleasing feature\, of wiring; the sturdiness and rigidity of Atwater Kent receiving sets is their the various parts, are but a few of its sureness of securing a desired broad­ features. Other structural details worthy casting station. , . /-,?i of particular note are : A printed list is supplied with each Variable condensers: plates--coun- set which gives the approximate dial You Won't Have terbalanced; bearings-adjustable cone, setting of many of the well-known machine ground; contact spring-phos­ broadcasting stations. With this key to phor bronze. list in hand, the owner of an Atwater Dials: drilled and reamed after Kent can tune in a series of desired sta­ Pursue moulding, assuring balance and accurate tions, or stations operating on similar fit on the condenser shaft. wavelengths. 13y writing down the HAPPINESS Rheostats : phosphor bronze spring dial readings opposite the names of the You can ha ve it right at your elbow contact, sliding on s piral resistance coil, stations, make up a list or "log." to while away the time 'til old Lady giving smooth a nd positive action. Mode1'20 is a powerful receiver capable Static gets off the line! Tube sockets: heavy hrass set in of operating a loud speaker under all You' lI have no trouble getting moulded Ba kelite hase with phosphor conditions where broadcasting is at all station Z-I-F-F-S, because you'lI bronze COn tact springs, corrugated to practicable--hence ear phones are unne­ find it is always tuned in to catch make good contact. cessary. It compriscs two stages of your funny bone's wavelength, and Transfornlers: special Atwater Kent tuned radio frequency amplification, a is more ticklish to your giggle box than the finest cat whisker! design ca pable of receiving all broad­ detector and two stages of audio f re­ ZIFFS, Badzib's Book oj Art casting. quency amplification with three tuning and Wit, is the only humorous Gri(1 leak: special cartridge type, dials. It is non-radiating and non­ monthly of its kind on the market, absolutely quiet in operation. squealing. and is crammed full of the best Wiring : tinned copper with all joints Dimensions: Height, 8 1-2 in.; length, artists and funstcrs in the world! firmly soldere(I, spaghetti covered where 26 in.; depth, 8 3-4 in. Number of tubes Exclusive Photo Section! Com­ there is a difference in potential. required,S. plete gallery of French-American Shielding: a metal panel on the Part No. 4640, Model 20 Cabinet Art Studies in color! Fifty pages of illustrations! Pep, Ginger, Punch I cabinet receivers and metal shields on Receiving Set, $100.00. condensers of the open mo(lels entirely Open receiver, same as Model 20 but ALL FOR TWO BITS! eliminate all body ca pacity. without cabinet- 58S.00. Pick This Out On Loud speaker : fa bricated entirely of metal, the same as the vast majority of New Studios Ready for Your Piccolo J the finest band instruments. Ewe" tho· your Jet is growling D iaphragms: of special alloy metal, WCCO 'Til you Ih ink a cal j,$ howling And Ihe music comes in wailing. hissing sniff., unusually large in diameter, assuring \Vork has started On the new Saint You will giligl •• gr in and chuckle great volume without distortion. Paul studios of the Gold Medal Sta­ 'TII you hafta loos< Ihe /:trckl. tion, Saint Paul-Minneapolis, WCCO. On your belt. if y ou·.e Ihe latNC book of ZIFFS Magnets: special Atwater Kent, re­ quiring nO extra batteries. These studios will be among the most uni­ You wouldn't go fishing without Ma ny t ypes of radio receiving sets quely located in the world. They are being bait, would you ' Well, then, don't deliver a sufficient volume of sound from built in Saint Paul's new Union Depot, try to get Hong Kong on a stormy night with a crystal set, till you've distant broa(lcast ing stations, but they used hy nine railroads. The studios, put your John Henry on the tag are not selective-that is, they Cannot reception room, and executive offices, below: separate two stations, both broadcasting will be at the left of the concourse at the same time on wa ves of nearly through which all persons pass going to rzlFFS, ------, the same wavelength. and from the trains. 608 South Dearborn, Chicago, Ill. I Dcar Badzlb: A regular $25 loud speaker for I got a radio. I got Hawaii. I got drowned $16. Loud, dear, mintermediate frequency ments. transformers. These are points Gl, G2, and G3 respectively. (lPERMITS-Testing of Attach the lug at the -1 1-4 inch section of lead No. 2 to the rOtor plate;; of tHe Multiple reading instrument "A" and "8" batteries loop tuning condenser at II 1. The tap with self (;ontained swit(;b. from panel of your set. on this same lead connects to the stator plates of the balancing condenser at 112. The other end of this lead later con­ (lEvery Radio "Fan" nects to one side of the loop. should have our 15 -8 cat­ Attach the lug at the end of the i 1-4 * alog. inch section of lead No. 15 to t he rotor plates of the balancing condenser at 11. The tap in this lead connects to Order from Dealer the plate of the first detector tube at 12 and the remaining lug attaches to the "Plus" terminal of the first intermediate Jewell Electrical Instrument Co. frequency transformer at 13. The lug at the end of the 7 1-2 inch 1650 Walnut St. Chicago section of lead l'\ o. 6 attaches to the lower Jack at 01. The next tap COnnects to "Z5 Years Making Good Instruments" the B Positive terminal On the second audio frequency transformer at 02. The remaining lugs attach to the .. Plus" terminals on the fourth (or filter trans­ former), the third and second interme­ diate transformers respectively. These connections are m ade at points 03, 04, and 05. The oscillator coupler should now be The Radio Age Annual for 1924! bolted to the sub base. Use 6-32x5-16 inch machine screws for this purpose. ONL Y A FEW LEFT AT SOc EACH Before attaching the socket strip be sure that all of thc wircs which you If you have not bought your copy of the famous have attached so far are as close to the RADIO AGE ANNUAL for 1924, you may get one base board as possible. This is One of at a special price of 50 cents by filling in the coupon the few "don'ts" in these instructions and should be obsen·ed. below and sending it with stamps, money order or The socket strip is attached by means draft, at once. The supply is nearly exhausted, and of 6-32x1 3-4 inch machine screws. no more will be printed, so ACT NOW! Run the bolt through the base board, place a brass washer under a 6-32 3-8 inch nut and secure it firml y. Then 1924 ANNUAL COUPON run another 3-8 inch nut down the bolt Radio Age, Inc., about three quarters of the way. The 500 N. Dearborn St., socket strip is now placed in position a nd Chicago, Ill. the loose nuts On the underside of the Gentlemen: Please find enclosed 50 cents, for which you may send me a strip run up to the correct point. Fasten copy of the RADIO AGE ANNUAL for 1924, in accordance with your special the strip firmly in place by nuts screwed price offer for April. on from the top and you are ready to resume wiring. Name.__ ___ ...... _._ ...... _. __ .. _. __ ._.. _ ...... _ ...... _ ..._ ...... _ ...... _ ...... Lead No. 25 is now completed from G4 on the .006 to Gl, the Filament terminal ·Address. __ ._ .... _ .. _ ...... _ .. _ .. _ .. _ .. _ .. __.... _ ...... _ .. _.. _ ...... _ ...... _ ...... _. _ ...... of the third inten1'l.ediate frequency City._...... _ .. _ ._ .. _ .. _ _ ._._ ..... __ ...... _ ...... _._.... State. ____ ...... transformer. • ~2S Lead No. 22 is completed by connect­ ing from 06 on the other .006 condenser to the "Plus" terminal on the fourth or filter transformer. 03. Connect lead No. 26 from C4 on the .005 condenser to the B plus terminal on the first audio frequency transformer, "to any MUar WL W, the Crosley station is in H a rrison , IF stand against the Radio beyond IUU'thinc YOU .. or board belor•• and WSA1, The U. S. Playing Card KARAS HARMONIK Corporation of America, they can Arntllifiee low. middle aud bit:h Station is in :\Tason, Ohio. Radio do it in the most pra:tical way by tonee--e.l1to tbe same big volume. officials in Washington are disposed to thUi eUminat.in« distortion. Brines sending in $2.50 for a year's sub­ out the vita bannoDie~ and over. grant qualified Class R stations similar tOnee of music. Priee '7.00. Writo _ scription or if they are already sub­ 11: ..... Elutri, Co.. D,Pt SS . 93 4042 N. R.. iw.lI St .. Chicago authority for increased pO\\'er, if their transmitters are set up outside the cro\\ d­ scribers, urge a friend to subscribe. ed urban districts. We believe the fans are with us. Round-Up Number of RADIO WEAF, the .\. T. &: T . Co., station in Address RADIO AGE, Inc., 500 N. AGE-August-on sale July New York has been authorized to increase Dearborn St., Chicago, Ill. 15. Blueprints of a complete its power to 2500 watts, being now the j radio education. next highest po\\'ered station. RADIO AGE SUBSCRIPTION BLANK Radio Age, Inc., 500 ~orth Dearborn Street, $2.50 A YEAR Chicago Gentlemen: Plea5e enter roy sub5Cription for R:\DIO .. \GE. the Magazine of t he Hour. fc.r one year. beginning with your n""t is..-ue. for which I enclose $2 .50.

Nnrne._ ...... _._ .. _. _ ....._ ... _____.

Street .\ddr"-S-o ... _ . __. .. _.. ___ ..... _ ... _ ...... _._ ...... _._._

I City .

State _ - -··-·-···- ·---s;,-nd ~ a~.-~o;;-.;y· ;;nj.;~- C;~ ·draft.'""""'·····-····-·······- · ·-· ····· ......

J(. Tested Ilnd ApPToved by RADIO AGE J(. 58 RADIO AGEjor July, 1925 The }.[agazine oj the Hour Tracing the I nteresting Ancestry of Your Receiver By FRANI( D. PEARNE

T DOES not seem so long ago that arrangements being only improvements this great range is of no particular value. we were listening to the now almost which are bound to come from this vast Regeneration and radio frequency I forgotten spark signals with the army of experimenters. Before the amplification have made distant recep­ simple little crystal set, which at that World War, Major Armstrong announced tion possible. Here, again, we find that time was considered one of the wonders his regenerative circuit, which was a we are back to the old basic circuits. of the age. basic idea, but since that time the only Radio frequency amplification is not new Interest in this, however, was confined distinctive new circuit which has but the method of tuning it, the construc­ to a few amateurs who studied the code appeared is the reflex, the production of tion of the transformers, neutralizing and enjoyed a n evening's chat with their which is generally attributed to Prof. the feed-back, and many other improve­ friends. Then came the radio telephone, Marius Latour of France, and Arm­ ments are to be found in these improved by means of which voice and music could strong's Superheterody ne. circuits. • be heard with these rudely constructed Today there are hundreds of sets The one bad feature of radio frequency and inefficient sets. Two broadcasting advertised, all of which are merely modi­ amplification has always been the ten­ stations began to send out musical pro­ fications a nd additions to these five or dency of one stage to feed back energy grams and the a mateur began to be six basic circuits. Among these are the to another, thus setting up undesirable popular. People began to call at his little single-circuit rege nerative, three circuit oscillatio ns with the resultant howling station and marvel at this new scientific regenerative, superregenerative, and other and squealing. Different methods of toy, to askhisadvice as to how they, too, forms of regenerative or radio frequency overcoming this are found in many of might build a set and e njoy this pleasure, amplcfuation. From this li st many com­ the standard sets now in use. The not because of any particular desire to binations have been made, radio f requeney neutrodyne, for example, overcomes this learn the principles of radio communica­ amplification has been a dded a nd hun­ difficulty, by neutralizing the inherent tion but because they wanted to hearthis dreds of little kinks here and there have capacity of the tube. By this means all music coming from the air and to enter­ been incorporated, but a close analysis the advantages of radio frequency ampli­ tain their friends with this newly found· will reveal the fact that no radical fication are realized and distant recep­ amusement. changes in the old basic principles have tion is easily obtained. More broadcasting stations began to been made. There are many people at operate and the fever spread until at the present time who want to purchase Importance of Selectivity the present time radio has grown to be sets and who are holding off and waiting N the other hand, this radio frequency one of the greatest industries in the in the fear that something new is shortly O amplification of the neutrodyne world. In the beginning, it was difficult going to develop which will make their would be of little value if the set were not to construct even the simple crystal set, selection obsolete. selective. The regenerative receiver, the parts having to be constructed by A Foolish Idea however, makes use of the feed-back the operator himself. We hadn't a radio method to gain amplification. It has store on every corner as we now have. HIS is a fool ish idea which is not the bad feature of radiation, which is I t was real work. T borne out by the past. It is true, per­ one of the greatest troubles the broad­ haps, and very probable that many new Improvement Arrh'es cast listener has to contend with. Radia­ sets will appear on the market in the tion from a nearby set will sometimes ITH the opening up of more broad­ next year, but it is not at a ll proba ble completely detune a receiver which is Wcastingstationsand the increase in the that any radical change will take place. tuned to a distant station and will cause number of fans, came the demand for There is, of course, a possibility that the enough shrieks and howls to spoil a good something better in the way of a re­ wave band of the broadcasting stat ions program. This is not the fault of the ceiving set. Vacuum tubes began to may be slightly increased, due to the regenerative set, but rather the careless­ replace the crystal, because by their use fact that so many applications for ness of the person operating it, for it is the signals were not only detected as they licenses are being received by t he Govern­ quite possible to so adjust it that no were with the crystal, but they were ment that they find t he present wave radiation t akes place. amplified also, this being made possible band too narrow t o accommodate all of Amplification by regeneration is caused by the addition of the third element in the them a nd keep t he proper separation. by feeding back some of the amplified tube, called the grid, which was produced But one may rest assured that nothing signal in the plate circuit to the grid. by the inventive genius of Dr. Lee De will be done to make the present type of This builds up the strength of the signa.!. Forest. These vacuum tubes, however, receiving set obsolete. and is really a method of amplification. were expensive in the old days and only E xperiments have shown that it is When a signal strikes the grid, it is those who could afford luxuries were possible to broadcast on wavelengths as rectified and amplified in the usual way_ I ucky enough to possess them. low as 100 meters, but it will probably A tuned plate circuit is employed and Today they may be had for the price of be a long t ime before the wave band will when part of the varying current in the one dollar and up, and the simple little be broa dened to this point. The fac~ plate circuit is fed back to the grid, the crystal has lost its prestige. With the that so many stat io ns a re now in opera­ plate Current is again varied. This.in advent of the vacuum tube more of t hese tion has made the question of selectivity turn again increases the plate circuit amateurs became interested in the actual one of vital importance. In the old days, current, which "is again fed back to the science and as a result of their untiring when only a few stations were sending grid. This process continues until the efforts, we now have radio as it is today. out their programs, it made little differ­ signal becomes stabilized and has the T hey created the demand for better ence whether or not the set was selective, effect of prolonging and building up the apparatus a nd improved upon the few but today things are changed. Selectivity basic circuits until we now have hundreds is the watchword. The question of signal. The time required for all of this of circuits in use, with more coming all distant reception has been well taken building up is so short that it does Dot the time. care of, and many of the present day in any way distort the signal. But what of these circuits? As a receivers will pick up programs from There are many types of regenerative matter of fact, there are only a few of coast to coast and from Alaska to South circuits on the market today, but the}· these basic circuits, most of the new America, but if the set is not selective, all work On the same basic principle. RADIO AGE for July, 1925 The Magazine of the Hour 59

But many of them are better than others, due to the fact that different types of inductances are used, and varying methods of coupling the circuits. A loose coupling between the primary and secondary circuits will always give much better selectivity than a tight one. A fair example of this is seen in the ultra­ JEFFERSON audion receiver. Here there are many variations. Sometimes the tuning in­ ductance consists of a variometer which TRANSFORMERS is connected in series with a variable con­ denser. Doth the inductance and the condenser are variable. The same cir­ cuit is often used \~; ith a fixed inductance and a variable condenser. Either of these work very well, but naturally a closer adjustment may be made if both the inductance and the capacity are adjustable. Loses Its Selectivity HIS type of receiver is known to T have a long range, but because of the direct coupling between the primary and secondary circuits, it loses much of its selectivity. Dy using a single inductance in the aerial circuit, and placing it near the variometer so as to afford an induc- tive coupling, itstill retains its long range and the selectivity is greatly increa sed. The super-heterodyne is well known for 1 long range and selectivity. In this SIFT OUT THE S~R STATIC arrangement another ba d feature of radio frequency amplification is overcome. It's the season when aggravating radio imps seriously This is the tendency of such transformers interfere with smooth reception on most sets- but to work at their greatest efficiency at there's a way to make your set behave better. Jefferson one certain frequency and the dropping Transfonners will bring in summer programs with ofT of this efficiency as the frequency almost cold-weather clearness. Extra care in manu­ \'aries from their natural frequency. In this set, a local oscillator is used, which facture and the benefit of greater experience by the ,Sets up oscillations of nearly the same world's largest manufact urers of small transformers frequency as that of the incoming wave, give Jefferson Transformers the lead in audio tone causing a beat frequency which is the amplification. They will give remarkable results for result of the two, to pass through the you this summer. You'll find them at the best radio radio frequency transformers. As the dealers. local oscillator is under the control of the operator, this beat frequency may be JEFFERSON ELECTRIC MFG. CO. made the same in any case, regardless of the frequency of the incoming wave, 501 So. Green St. making it possible to always work the Chicago, Illinois transformers at their natural frequency, regardless of what the frequency of the Makers of Jeoffeonon Rodio Tube Rf:­ juvenatora; RAdiO. B~1l Rin ~i ng and incoming wave may be. Thus the set Tor TranJorrnr.... Jeffrrson Spark is always working at its greatest efficiency Co... for Autornobilr. StationAry and Marine Encinas: Jflfet"Slon Oil R~rne ... and even the most feeble wave may be lenition Coila and TranefDl'mera. picked up and amplified to great volume. The reflex set is peculiar in that it will produce more amplification with less tubes. This is done by making some of the tubes do double duty. After t he I radio frequency tubes have amplified the signal and it has passed t hrough the that the uninitiated beginner has a hard detector and reduced to audio frequency, time to decide on which one to purchase. ~.Drn~© ~if it is again passed through the radio In t he August issue of the RADIO l.kA~m ~ frequency tubes at audio frequency, AGE, all of the basic circuits will be ill ©J];@ thus operating them at both radio a nd shown in blueprint form, which has /Ot' LJisiodlonless .Amp/~c'UiOd audio frequency. This is not only a made this maga zine so popular with the 12.000. 4S.000. SO.OOO. 100.000 Ohm.... Ll" Sl.50 r-acb. Spr-ciAl S Uies to Order 52.50 "acb. saving in the original cost of installa­ fans. In this issue, which is to be a de­ Denlrn. wnte fo r discouot.. When. Bdl~ R r~ton&U Gr" m.4lk tA.rv toill he Crc.&efflt.!. tion, but less hattery is also required to luxe number, approxima tely eighty pages Crescent Radio Supply Co .. 5 Liberty SI • J.maic., N. Y. operate the filaments than would be will be given over to this subject. Aside necessary in other types of receivers. from the blueprints of original circuits, :'Ilany different reflex circuits have been many modifica tions and methods of SALESPEAKE devised, but while they differ in the amplification will be shown, ma king it apparatus used, they all come hack to possible for one to trace the history the same basic principle. of almost any set in existence. A careful Because of the many deviations from study of these circuits will in a measure these basic circuits, there are hundreds of give an idea of just what changes they different sets for sale and it is nO wonder have gone through in the last few yea rs. J(. Tested a.nd A7171ro vl'a />'11 RADIO AGE ;0: 60 RADIO AGE/or July, 1925 The Magazine 0/ the Hour Some of the T ricks Summer The Radio Spies FREE Static Plays (Continued j rom page 51) I , (Co1lti1lttedjrom page 2-+) such a poSition, to sec ure certain priv~te papers, Subscriptions to papers and specifications and other papers of the De its atmosphere during that season~ Un­ Forest Company and deliver the ,same to him. She fortunately, no way of a\'oiding this declined to ta ke the position." ' RADIO AGE difficulty is known today. The trans­ Sylvester W. Crowley. manager ' of the audion division of thc' De Forest Radio Company, said he For Your Time! oceanic radio stations have to be equipped employed Cecclia Lambert, ' mentioned in th~ Radio Age will give a year',s with high power apparatus in order to Bowlby and Jennings affidavits. She was discharged free subscription to this mag­ work through the bad periods of the day April 16, 1925. "because it was discovered that she a~ine to any reader who will and year, although at certain times of was employed by the Radio Corporation of America. obtain for us a news-dealer who paid a salary by them and was making reports of the year and day less power may be complainant's business secrets to that company." will handle our magazine in a town used, as e\'idenced by the successful Crowley says he was present on April 16. whcre wc are not already repre­ trans-atlantic transmission by lo w power 1925. when )Iiss Lambert admitted having furnished scntcd. confidential reports to Harley, who assigned her to I f you are now a subscriber to amateur stations. work for various concerns. receiving wages from RADIO AGE, you can refer this For the sake of clearness, we have so he r e mploy~r as wcll as salary and expenses from notice to one of your friends, who far described the cause of fading signals Harley. will doubtless be pleased to take YCr . Luce. PresidE'nt of the De Forest Company. as due to obstructions in the path of the says that for eleven years his concern has been mak­ advantage of this opportunity. radio waves. Actua lly, the radio clouds ing. leasing a nd selling radio receiving apparatus Or you may extend your own sub­ sometimes reflect the waves, much as a and a uaion tuhes. For several years the defendant scriPtion for one year without cost. mirror does a light wave, a n<1 so very has been carrying on the same business with the T his offe r is to remain in effect Possible exception of manufacturing, he declares . until further notice. pecu liar reception effects are someti mes \Vhile he has no definite. information regarding the noticed. Sometimes the signals are made defcndant's m'!nufacturing business. he says that as a Free Subscriptio n Blan k stronger instead of weaker, sometimes resul t of agreements between the defendant. the G eneral Electric Company and the Westinghouse RADIO AGE' Inc" they may be lost altogether, as the E lectric and Manufacturing Company the defend­ 500 N . Dearborn St., Chic,,!:'>. III. : several effects of reflection an(\ absorp­ Gentlemen : I n order to /let a free sub­ a , t was required to buy part of what it sells from script ion t o RADIO AGE for onc year.­ tion combine. e ach company. These three companies, with the I herewith send you the name of a dealer And now, let us consider that arch American T elephone and Telegraph Company have who will sell RADIO AGE in the e ity men­ Ii.:..-nsccl each other under various patents. He tioned, It is understood that if you already enemy of radio--Ol

By R. H. Hopkins the executioner's desire for a negative HE proper way to tell about Mc­ reply, was invariably "yes." I offer a c:onlprehensive. expe- I efficient service for his T Murdo Silver would no doubt be to Practice Makes Perfect prompt, legal protection nnd the say "Once Upon a Time," or, to become development of his proposition. Send sketch of model and descrip­ somewhat more modern, we might head TRANGE as it may seem, these two tIon, for advice as to cost, search the dissertation "From Nothing to Some­ S bits of instruction stuck firmly in the through prior United States paten ts, thing," or one might even resort to .the young man's mind. The next day the elc. Preliminary advice cladly furniohed without charge. time-honored, and (we hope) bUried, cook, called to the back yard of the family My experience and familiarity style of Horatio Alger. residence by unearthly yel1~, beheld a with varioua arts frequently enablo But none of these styles seems to fit strange sight. Sitting astride a saw­ me to accurately advise clients as horse was a young Mexican boy hurriedly to probabl.. pa~entability before properly, so we wi 11 confi ne ourselves they go to any expense. (not the regal, but the editorial "we") conscripted for the part of the convict. to a plain statement His hands were Booklet of ",,'uable information and form for properly disclo.;n" your of facts concerning tightly tied, and a id.a 'r•• on reque.t. Writ. today. the not altogether very heavy rope, al­ uneventful life of a most thicker than RICHARD B. OWEN, Patent Lawyer young man badly his pudgy arms, con­ 81 Owen Bldg., Washington, D. C. nected his unwilling 2278-M Woolworth Bldg., N. Y. City bitten with the radio hug, who at the age neck with the limb of 22 is the presi­ of a small tree di­ dent of a prominent rectly above him. radio concern and He was calling loud­ whose name is more ly upon all the sain ts than well known to known to him in a many thousands of somewhat unintel­ radio fans. ligible imitation of Born in a small Spanish. Next to college town in west­ him stood one of the ern New York, the "Silver Gang," ask­ son of a c;:ollege pro­ ing loudly and re­ fessor, his ear I y peatedly whether he years were spent u n­ "joi ned or died." eventfullY in caus­ The executioner, in ing his fond parents anticipation of the just a little hit more reply, held the noz­ than the usual zle of a length of a mount of conster­ garden hose in hi s nation, for at a very hand. early age his Some distance thoughts turned to away, in the wash­ things mechanical. boiler, stood the in­ The result was no stigator of this new more than could be M cMurdo Silver game, holding the expected. l\lany other end of the hose peculiar and supposedly original con­ in one hand, while in the other was trivances marIe their appearance, most a nother piece of hose which reached back of them designed to provide a hearty and to the gibbet and terminated in the stimulating welcome for the college stu­ grimy grip of the assistant executioner. dents who called upon his father in As the victim's cries were uttered, the search of wisdom. executioner shouted them into one hose, Frequently the searchers were dis­ through which they were presumably couraged, hut it is interesting to the transmitted to the ship at sea, simulated casual observer of later years to perceive by t he waSh-boiler. From there, through that these and sundry other arrange­ the other hose, the verdict was again ments most frequently resulted in the shouted in a high falsetto to the assistant acquisition of wisnom. executioner, who in turn put the all­ $ILV£R Radio first entered l\lcl\I urdo Silver's important question to the prisoner. consciousness ea rly in 1912. Someone, In this way, wisdom was assimilated Dealers! desiring to keep the young hopeful's by the analytical mind of the young; mind well abreast of the times, read him communication with ships coulWireless Telegraphy" a nd through rubber hose, since one couldn't with latest wholesale and retail radio bargains. Also ask for our athactive how it enaLled ships at sea to keep in shout se\'eral thousand miles. And to proposition 1 o radio dealers on nationally unbroken touch with the world while use "wireless telegraphY" one had to advert, s~d lines. they were out upon the bosom of the have a reason, which was opportunely SILVER-MARSHALL, INC. bounding brine. provided by the recalcitrant son of a 10SA-S Wabash Av. Chicago At the same time an account was l\Iexican villager, who might even yet also read, with true rele ance, of be reclaimed to the cause of the law by the Mexican Rurales, a troop of mounted strong-rope methods and the marvels of police recruited from criminals by radio. MARSHALL the simple and masterly expedient Thus was the youth of this young man of catching one, putting a rope around spent, alternating hetween the heights of his neck, placing him upon a horse all the Sierras and the ordered calm of a ready to he gently stroked with a whip, college town, the main street of which and asking the individual so situated if was shaded by towering elms almost as he wished to become a Rurale, or if he drowsy as the village itself. Out this was preferred to dismount from his steed not for long, and the association of garden post-haste and remain in the unenviable hose and radio having been demolished position of hanging by his neck to a nice along with other illusions, the big city tree limb, separated from it by several claimed our subject. There, mOre stren­ feet of rope, and .from the ground by uous pastimes being taboo, radio was several more feet. The a nswer, unless taken up with renewed vigor, and a posi- choked off by the culprit's emotion, or (Turn to page 7Z) ¥o Tested and .4.ppToved by RADIO AGE ¥o RADIO AGE for July, 1925 The Magazine of the IIoltr 6.1 Underground Radio from Coast to Coast !VIA.TC t-I E [;) By JAMES E. SMITH President of National Radio Institute D r. James Harris Rogers, whose achievements with underground trans­ It] lUJ mission are far famed, has climaxed all ~nJEK his tests by sending radio waves from CONDENSERS Hyattsville, .Md., to Los Angeles, Calif., a distance of 3,000 miles. Sign·als at Los Angeles, according to the report, "were coming in finely with little fading." This record eclipses all previous under­ ground records (these also having heen set hy Dr. Rogers' experiments), and opens the way, according to many leading More Monev For You scientists, to an immeasurable develop­ ment and improvement in methods of radio transmission. This achievement of coast to coast in RADIO transmission through the ground crowns \\ith success an undertaking which was HE amazing expansion of Hadio has opened U]J hundreds Know t he sat isfaction and ease of tuning first bro ll g ht forward and attempted by T of wonderful new positions on that come when all dials read alike or Dr. Rogers in 1908. It overthrows the land and sea. Big salaries,fascinat­ eliminate logging and dial by wave­ dicta of men no less eminent than Mar­ ing, easy ,,-ork, short hours, and a lengths. Use DUPLEX Matched Con­ coni, who scoffed at the proposal to wonderful future are offered to am­ densers. Made in strict accordance with radiate waves through the earths' crllst. bitious men to get into Hadio now. B ureau of Standards specifications. As a direct result of Dr. Rogers' Take a.lvantal:'e of these won.leriul op~or­ Used in the famous Thermiodyne. Test­ latest accomplish ment, it is now possihle tunities to step into a big paying position in that the broadcasting lower, the expen­ this great new field. You can stay at home ed, matched, packed and sealed, to and work up to a position r.aying up to remain unopened until used. Ask your sive aerial extending sometimes 400 to $10.000 a year, or Radio offers you an oppor­ dealer. 600 feet in the air, may hecome in the tunity to travel an.l sec the worl

KOKA Wutinzt,o~e Electric & tt1fll[. Co .• . . •. . , . . .. . _. .. . , .. Eut Pitt.... burlrh. Pt'., lOW KFUZ 24C KOLR Radio EI&ctric Co ...... , .. •..• . •...... Devils Lake, N. D . 23. KFVC 248 KDPM W ..tingho\l!18 Electrio ~t. Mfa. Co ...... •...... ClevelI\Qd. Ohio 270 KFVD 202 KDYI. ~"wholl 'u, HotAI ...... •...... S.lt [.oake City, Uta.h 250 KFVE 245 KDZB Frnnk E . Siefert ...... , .. .. . _ .. _.•. . __ • ...... • 0 • • • BB.kere6old. C.lif. 240 KrvF 208 KDZI Electrio Supply Co. ....• , ...... ' . • •. . .. . •..• . . Won.atcbee, Wn.':Ih. 360 KFVG ¥£~~t~~~cHk .· .•.· .·i )•. •.•. · . .• .• \ ,... ;~~~ 236 KFAD McArthur Bra:.. Mercantil. Co .. .. , •. , ...... •...... Pboenit. Ariz . 273 KFVII 'Vba.n Radio ~hoo (Ilerhert Wh&r:ll), •.•• • .. . • . • . •.. • • ~Ianhattao . KaIl8 .. 218 KFAE St.nte Collo.re of \Vasblnct.OD . . . . . • ..• . . .• ...... •.. . Pullma.n. Wlt3b. J48 KFVI 218 KFAF "'loetllrn Itl\dio Corvoratioo . . ... '" . . . . , . •. • • . . . . . , ...... Denver. Colo. 278 KFVJ ~t~~Q~~~;:t 1J~~;'h ~~~~ . ~'~ ~~I~ : :: : : :: : : :~ :: : : : : :: : : S~:~~ftr:lver. Colo. 254 KLZ -:;:'~~~d!l P~~,!~~~n«c~~ : ·. ~'. '. '. .. : ~ '. '.'. ", .. '... .. : .. ~ '. .. .• ...... , ...... '. '. ~~~':::;'. g~~~: 283 KFEQ J. L. Scrolll:r.in ...... , ...... " ...... ' ...... , ...... Oak, Nehr, 263 KMJ SaD JO:\Quin Light & Po ... er Corp .. . . , . • , . • . . ",. , . , . , . . .. . FrelllDo. Calif. 243 KFER Auto Ehu'Jtric SlI'Irvicill Co ...... , ..... , ...... F ort Dod«e, 10wI\ 231 KMO Love E lectric Co. .. , ...... , . . . . .• ...... • , ...... Tacoma. Wo.sb. 250 KFEY Blinker Hi1t &: 81lllivaD l\[iuinC a.nd Concentr!t.tim£ Co ...... , KellolrC. Idtlho 233 KNX Lo! Anaele! EveniD« Ezpreal . .. . • , ...... , ...... LOll An£ele!l. C ..lif. 337 K FFP Fir ~ t Ba Dt~t Church ... , .. ,...... " . . . .. Moherly. Mo. 266 KOA Geneml Electric Co...... Denver, Colo, 323 K FFV Graoelnnd COlle.ro ...... Lamont. [o... a 280 KOB !\'e" l\t[e.ico Col1e.re of AirTlcnlture .. Mechanio Arts. Btate Collel'e. N. Me • . 348 KFGB IIeirlhrerlor Rl\. rH o Supply Co. , .. , ....•...... •...... Utica.. N eb. 224 KOP Detroit Police Department ...... Detroit. I\ticb. 286 KFGC Loui... iana StMf't Univet'llitY ...... Ba.ton Houlite. La. 2S4 KPO 428 KFGD Chlck3li.ha RadiO &: Electric Co...•...... •...•. , ...... Chicka.aha. Okla. 2418 KPPC 22e KFGlI Lelllnd 8 fMtoro Univf'rsitY ...... , .. , ...... Stanford Univer .. ity, Calif. 273 KPRC 270 KFGQ CrntY IIfLrdwarfIJ Co. . . , ...... , .... ,. , . . , ...... , ... I\oone. lo... a 226 KQV 270 KFIIA We-.hrn Rt'Lt. .. ~"l1''''tA of Colorado ...... •... •...... GuDn~oD. Colo. 252 KOW 22G KFliH AmhrolWt A . McCue . . .•...... , . • . . . ••... . •.. . , • ...... ~~ Hny. Wash. 281 KRE ~~~f¥~£L~f ii\?~{~ 275 KFlIL Penn CoIl8«e, ...... , . . , .•. ··, . . · . ···,. · ·· .•. . ·· .. OakRloo!ta , 10"" 240 KSAC Kantll M Stnte Altric:ultural College. , . .. .•...... • • , .. " Manhattan, Kane. 341 KFI E. C . AnthonY, Inc ...... , ...... , .... Lo.. An5tela.... Calif. 468 KSD Post Di:lDn.tf'h (Pulitl:cr PUh. CoJ ...... , ...... • ...... 8t. r.oula. Mo. 645 KFIF BenMJn Polytechnio In~tltuto ...... • ..• ...... P ortlaDd. Ore4t. 248 KSL H.atlio Scrvi<"O Corl>. nf U t ah ...... •.• . •. . , • . .. Salt. Lake City. Utah 299 KFIO ~'ortb ~entr41 I1iKb School ...... • . , .....' •.... , . , . . . . , . Spokane. W",,,h. 252 KTCL Ameri.("nD Radio Telflphnne Co .• Inc...... Seattle, Wn.sh. 306 KFI8 Firat I\[ethodi",t Chur-eh ...... ,...... Ya kima, ,,'a!th. 242 KTHS New A rlin&ton Hotel Co...... ' " .• . " ...... " ...... Hot 8Prinh. Ark. 375 KFI Alukn Elot"t.rie Li~ht &: Power Co...... Juneau. AIA8ka . 226 KTW 455 KFIX ReorPnited Chure ~1 of J" \l ~ Cbri",t of latter naY & iot.... Indehendence. Mo. 240 KUO ~~:~r::hlr~~rti~':t '6~~~~~ :::::.-: .' ::.-:: .-:::.- :::.-: ::: : 8~~ . ~::!~~,~:t, : 248 KFIZ DaUy Commflnn'e: ~ lth aDd Oecllr A , HUel ll man ...... Fond du Lac, Wis. 273 K UOM Rtau, Cnivonity of Montana ...... • .. ~ ... , M"'ouln. M ODt..ana 244 KFJB Marllhall Electric,,1 Co ...... • ...... 1\[lIor!thlllltown, Iowa 2418 KWG Portllble W irelel' s TelePhono Co ...... , ...... 8tocktoo., CaIH. 248 KFJC It, B. FfoJ:;\n (Epu.r. opnl Church}...... J unrlio n City. 1i'llnSM 219 KWKC 236 KFJF Nl\tiona-1 RadiO M'1nufncttlrine- Co...... Oklahoma City, Okl.. 252 KYO 270 KFJI Liberty.nun,tre (E . E. I\t~ nh ) . . . , . . ...•.•...... Al'torla. Ore. 252 KYW 635 KFJL Hllrd .. o.clt J\[tl.nntncturinR' Co .... , .. , . . ... •...... Ottum... a . low. 2412 KZM 242 KFJM Univ&raitY of North Da-koto...... , G m nrl Fork_. N. Dak. 280 WAAB !~{~!~~~~lnF~T~ :: ~~.~i::: ~~::: :: :::::: ::: · :::: :: :: :::: :::::::. :: :::. ::~~~~;~:~~~~ 2.3 KFJR A!IIhleY C. Dixon &: Son...... •...... Steven·wille. 1\font. ( no"r) 258 WAAC 275 KFJX 10w1\ St~t8 Te\cher'" Collce ...... , ...... ~cwtar Fall ... [0.... 0. 280 WAAD 248 KFJY WAAF 28B KFJZ ~~nE.aR:n~~i~ . ~~. : .-: :: .. :.':::' ~:::::::::::.: : : ::::: : ~:~ ,~~~~ ' i:= ~:: WAAM 263 KFKA Colorarlo St.te Teachers Collelfe ...... , ...... Greeley. CoJo. 273 WAAW 285 KFKB DriDkley-JBne! Ho!tpital Alil'fl ci:a.tion ...... , ...... ~lilford. KftD~ . 288 WABA 227 Conway n ... dio La t."r:\torie·t ( Ben H. Woodruff) ...... Con... aY. Ark. 250 WABB 266 ~~~8 The Univllrllity of Kamllu ...... LawreDCCI. Kans. 275 WABI 240 KFKX We.. tin4tl,on .. e Electric" ManHfe- cturinlt Co ...... , .. HlL'l.tio«s. Nehr. 288 WABL ~~~~~~;~:~n c n:\~~l.i~ 283 KFLB BiR'nnl EI.. ctd c 1\fanufA,cturiD£ Co...... Menominee. ~ticb. 248 WABN g~:R::~~~~t I~: i.c~ .l ~~~~l . . ~~~I .e~~ : : .-.-:.- : .-.- .- .- __ .- __ .- .-.- .- .-: .- .-.-.- .- i.~~~~e~I~ : 244 KFLD WABO Lake Avenue Bavti"t Cburch ...... , . . .• . , ...... Roch_t.er. N. Y . 283 KFLP ~'~~~e~ ' J\~~eF"n~":r· . · : ·. · . ·. '. ·. ·. · . ·: , · . · . ·.· :::.·.·:: .':.·. · :.·.·.·.·.·.·.· .·cJ~:n~~~~ , i:: ~~: WABQ Haverford Con.p. ludio Club ...... , ..•.. , ...... " . • HRverford. p&. 281 KFLR Univenity of New Me.leo. ... • . . , • ...... , AlbUQuerque. New I\toltieo 254 WABR Scott Hilth School. N . W. n. Foley ...... " ...... '. ,._ , . . . Toledo. Ohio 270 KFLU Rio Grande fl,ulio Bupply Hou"e . .•• . .•.. .. . , ...... 8nn Benito, TeDt. 236 WABU Victor Talkin4t Machino Co.. . , ...... " ...... Camden, N. J. 224 KFLV Rev. A . T. F rykman. . •...... • .. •...... H.ockford. Ill. 229 WAaW Collel:o of WOO l'lter ...... , ...... • . . , ...... WOO.!l ter. Obio 234 KFLX Geor«e RoY Clo\uth . , . . . .. • ' ' ...... , .•.. , ... . . , .• , ... G.lvnton. Te.. 240 WABX 270 KFLZ WABY ~b'!:)' M~~a~~r. · j;:::.- ::: .. :.,.. ". ''':. .:: :::::.. :: .. :: ::: __ .~ .t : ~~:d:::bi~ip~: 242 KFMB WABZ Colil',mm Pisce Baptist Churcb .. ' ... , . '" ...... '" . . Ne ... Orl8aDe. La, 263 KFMQ WADC AileD T . Simmone (Allen Tbeatre} ...... •...... Akron. Ohio 258 KFMR WAFD 233 KFMT WAHG 315 KFMW W~~~~~:S }.ii:iCii,,~~ilt;lt{· ill WAMD ~~~~:~;..K~;~~~: :. :.:.: :,:.: :.:. ~ :.:.:. :.:. :. :.:.:.:. :.:.:.:.:.:.:.: .:.:.:. ~~i~~~~t~~: E;:t 244 KFMX WBAA 283 KFNF g~~:;o~i~ln~:. . ~. ', '. : '. ~ '. ~ '. : :: '. ::: ~ ~ ~ ~ ~ ~ '.: '. ~ : ~: : " ~ ~ ~~~!~~:~h . ~~~-:~ ~i: WBAC 331 KFNG \Vo .... ten· .. IbrU" RhOl> ...... • .. ...• . • • . " ...... Co1hone R~(lio Shop ...... ~ • ...... " .. ... Lon« 11",,,ch. Cahf. 234 WBBM g~&{:':'l.l~OX~~:~ •. ~~~~ ,h.~~~: ~ ..~~~~~~ : : :: : :: : : : : : ~ ~ : : : . : ~ct~c:~~ : ';~~ 22. KFOO L ntter D~ S:tint.. UniveTftitY . ...••... ,, · .. , .· · · ··, 8alt Lake City. Utah 261 WBBN 276 KFOP Rohrpr RIa.:: . Co .. , ...... •..... , ., . . , •...•..•... Mar'llhficlrl. Ore. 240 WBBP ~~::~e~':iRb ' R~b~i : :'- : : :::: .. '- :::: :.'::.-: :::: ::: :: ~ ~~~':~:: ~iiC~: 24. KFOR nl\vitf ~ity TIr. k F.1N'tric Co...... " ...... David City. Nehrl:l:'ll ka. 226 WBBR 273 KFOT ColteR''' Hill Radio Clnh ...... ···· ·· · ,. · Wir.hita. r{1\nttt-n.s 231 WB8S f!~~Bl\i~~t ~t~~~~~. :. :. :":".:.:...... :.: .". :. :.. .: ...... :.. :: .: ...... : ...... :. :.:.. ..~:~~E:~£ · t~: 252 KFOX Bonrrl or Erlue'ltion . Tecbnical H1R'h School . . .• , • . • ...... Oml'lba. Nf'hra!lk", 248 WBBU 224 KFOY WBBV JobD.:!lto ..... n Radio Co...... ,. , •...... , ... . . JohnAtown, h . 246 KFPG g~~;~~"~I~~ RD;~~i~ '- : .'::: ::: ,'::: :::,' __ : :::::.'.-.' __ .- .' : : [~8l~~:I~~·. ~~j\( : ~i: WBBX Ruffner Junior Hi«h SchooL ...... Norfolk. Va. 222 KFPL WBBY W&.'Jhincton Ll&bt Inf.DtrY Co. ··B·· 1l8tb IDf .. . .. , .. . . Cha.rleston, 8 . C . 268 KFPM ~beCNe~tlJ.!:~~ i iu· r~ · Q;: ...... '.'...... "...... ' ...... '.',...... ·. G ;~~!lNI~ : +:~:.: ~:~ WBBZ Nohle B. ""."c..... on ...... ~ ...... • ... • .. • ...... Indie.napolie. lad. 227 KFPR Lo:ot .-\n"f'l~!1 Co. Fm·... !'try D",pt .. . . '" . .. . , . .• .• .. ' .... . [~!t An«elM, Clllif. 231 WBCN FO:'IIter &:: McDoland, •. . •...... , .. . . •..• , . .. . . , ...... Chica.ro. Ill. 266 KFPT WBDC Ba.~r Laundry Co ...... , . "" ... . , Grand }t[lpide. Mloh. 25S KFPV , WB<:S Bli .. !t E18ctrie.l Schf)ol...... • " . •...... , ., , •. " ". T.koma Park Md. 222 KFPW ' WI\GA Jon .... Elec. il RAdio Mf&. Co __ , .. • . . •...... , . . " . . Ba.l tamore Md. 2S. KFPY WBOQ 238 KFIlA i~~~~1;~~!~~~JE.~ :: · ;- :· ; · ;· ;·;· ;·;- ; ·;· i· i·i·i·;-;·\.;·;·:·i·.;·;· ;- .T.~t~~~~E~f~l: 'i! Wq~ ~~!~~~ea~i~~ ~~~~[n};Oii~~ : : :: :: : ::~ : :: :: ::::: ', : ~ : ~~~.~~~:J~\'e~ ·P~: 28f KFQB The Sp... chlilfht PuhliJlh;nlit ~o ...... , ...... Fort Worth, T.... 221 WBQC Bell Radio C"oOrpor :L ti"n . . . . , .. • . . , . , . . •. ' " . .• •. . . • . . . . BirminKham, Ala. 248 KFQC WB~E B,.ltimor.- )t"dio Ezcbanp . •• .. , .• • .. .. • . " . . • . . • " , , . Wilkel'l·narr.-, PR. 211 WBS D. W . I\taY. [nc ...... ••• .• • • •• ...... , . • ...... Ne... ark N . J . 252 KF§KF PH ~F~l~ ~:;~~~ ,{~~~o: : ~~~~ : : : ::: :: : :.: ::.::.:-: :.::. ... :.:-:-:.. ~~~~i~!~~fJ:!~: m WBT Southl'!rn nadio Corp. . •...... ••...... , • .. . . . • ...... Charlotte. N. C . 278 KF R W.1t.er I.nFaYettfl F.1l.., . • • .. . • •• ~ • .• • . .. • , . • . .• , . Oklahom" City. Okla. 220 WBZ 333 KF T Te.M ~a.tiODAl Gllard ... • . .• . . . .•..... • . . , •. , .. .. • . . .. . D.-nni!'on. T",.eu 252 WCAD ~~7A~~n:;;.~~: fj~i~ e~!ity~ · :'-'-" .' '-'- '-'-.'.''- '- '-'-'-.' '- __ : : ::.- .-.-.- : ~,p. riC-:nei:~.l\J~y.- 280 WCAE KB.u{m&nn k B&er Cn .• 00 "I he Pittllhurlth Pres . . •. • ...... Pittabur&b, Pa. 451 KF§KF WU WCAG Clyd. R. Ib.nd"n ...... N .... 0,'...... La. 262 KF Y ~',~~~~!~,~~~ '. 'ri~~~ : :: ': : : ': :: : : : : : '...... : : ': : : : : : '::: : : ~~ .~~~~~~~~ ~ri:~: Hi WCAH Entrpkin Electric Co . .. , ...... • ...... Columbul. Obio 286 KFQZ Talt ItAdio Co ...... · ·· .. ··•·· • · · • · Holl .. :rood. C ..lif. 240 WCAJ !\'ehrMka Wp~leyan Univer!tity ..•..•....••. . , . .. . . 'O'nlTerAity PlAce. Nehr. 283 KFRC City of Paril!!l Dry Good:'ll Co• . ••• " •• . • •• .•• ••••••• • • San Fr!t.nc iA co. C ·,lif. 2fj8 WCAL Rt. Old (".... ()lIeli[e ., ...... North6e·d. Minn. 33S KFRM WCAO Santl.rll &. Staymn.n Co .. . . . , . . ' .. • ' . .• . , .. •• . • •• .. , ...... Ba1timof'& Md. 275 KFRU ~~f'~C~I · R~~~:nf!.;, :.-:.-.-.-::.' : ::.' .-:.':,'. '::':. ·.·:.·:.·.·::.·.·.·:.·... ~Br\ .. ~~~'. ~t\~·. ~:~ WCAP C!hMI\pe!\ke 111: Pot.oml\ TfJtephon8 Co .. .. '...... • , . WNlhiDgton, D . C. KFRW United Churchf'!' of Olympil:l . . .. . •...... •. . • .. .. Olympia. Wa'l.h. 220 WCAR Alamo R.dio Elflctric Co ...... ' " "" " " ., ...... 8.n Aotonio. Te •. 4"263 KFRX \YCAS W. H. Dun ... oody In~uAt r lal Inetitute ..•• • . •• . . • .. , .. .. f\.linne&PDlie , Minn. 280 K FRZ t~;l~~¥[~'E~~ ·: · :· : ·:·: ·:·:·:·:·: ·: ·:·: ·: · :·:·:·:·:·:·:.:.:.:.: .: .:.:.: . : ....: . 2i~~1~7£~·::ft,: ~~ WCAT State Colle&.- of l\1infJ !'I ...... , ...... Rapid City. 8 . Dak. 240 KFSG WCAU Durham &: Co...... , ...... , ...... PhiladeIDhia. Pa, 278 KFSY Thll Van Htarioon Co ...... , ..• . . . . . •.. · .. •...... H!"len • • ~Iont. 2fj. WCAX UnivftTtli ty of Vfllrm()nt . . __ ...... • ...... , ...... Burlincton, Vt. 250 KFUJ fl""flfllr PlumhinR' and HeBtinl: CQ ...... Br'-C"Ki"'n r irlR'~ , Minn. 242 WCAZ Carth ...", c"n.-&fI ...... ••..... , •. . .• • , . • ...... •Cartba.a:e. Ill. 246 KFlJL Thomae r.ot:.ran ..\ Broe. Muflic Co.. . • . .•.• , . ..• . . . .' . G ~IVe ,. tfln. Te.. 258 WCBA ~arl"", W . H ... iloachm . • ...... • ••. •. .... • ••• • • , . • , •• . . AllfJoto"n, P •. 280 WCBC University of ~1ichi£aD . ... . , • ...... • . . " .. , .. • . . ADn Arbor. Mich. 280 KFUM ':.' '. ': . '.' ...... A.'. '. ', '. '. ', •• •••••••••• •• •• KFUO ~~n~r~:I"'~e;cl~':1'rY ' , ~~~~~~.~~l>~~:~~,C~~: ~:~ WGBD Wilbur C . VolivA ...... •. ..•...... ••• . . .•...... •...... Zion.1n. 344 KFUP Fitzl' imrnonl'l Gftnerllol HosDitnl . . ..•. .• . . • •.•. .• ...... Denver. Colo. 234 WCBE {Thalt n"dio Co . • ...... , ~ ...... ••. .. " . • .. • .. . . , •. , . . Ne ... OrleaDJ!l. La. 283 KFUQ Juli111!!1 Bn1ntoD I\n,1 S()n.s Co ...... ••.•. , . , ••.• . . , • . , . SAD Frnnci..eo. Calif. 234 WCBF Paul J. MiU.' ...... Pittobu,gh. P •. ~3C KFlJR H , W. PoorY anti C . Reflfif'ld . ... . ' ... . . , ...... , ...... O&~en, U tah 224 WCBG How.rd ~. Willia.rna (Portallle} .. . . . • • .. , ~ . . . , . . , .. , . . PucaltOula.l\fiM. 268 KFlJS Lotlit L. Shftrman ...... • . . .. •• , . . . , •..... , . Oaklen.d, Cl\lif. 233 WCBH Univen,ity of MilUt...... • ...... •. O.ford. Mise. 242 KFUT Univeuity of Utah ...... •...... 8.lt Lake City, 'O'tab 27] weBI Nicoll, Duncftn & R\lr'h . Bemiol, Tennes.-.ee 240 KFUU ColhllrD. Radio [..1\), ,,...... • ••••.•••••.• . , . •.... • Alln LellLndra, Calif, 231 WCBJ J. C. MaUA ...... Jennin~l\. Loui81iaoa 244 KF1JY Irvibe M. Bouchll rd.. .. • ...... , . Butte, Mont. 254 WCBM Cha.rlell S ....n. . . . . Baltimore, Md. 22Y RADIO AGE JOT July, 1925 The Magazine of the Hour 65 Another Broadcasting Boom what ear.h potential radio entertainer is glad to assert, believing that he is telling Opens the truth. Probably some of them could INSTEAD of quieting down for the introduce new stars, but there are plenty Summer months, interest in radio as it is. They soon find that the field is broadcasting is reported as increasing _pretty well covered by the 566 stations, by many exponents of this art. At which are all experienced and have their least prospective broadcasting station own talent well lined up and trained, not owners are showing more activity tha~ to mention a large following of regular ever before, Department of Commerce fans. Everyone of these stations in records indicate. Although there are operation is trying its best to learn what 566 stations on the air today, utilizing the listeners want and to give it to them; every available broadcast wa"elength, many stations which failed so to do, have there are at least twenty applicants for fallen by the wayside, their experiments class B broadcast privileges and about a constituting a considerable financial loss. hundred individuals or organizations $ome organizations believe they could are said to be seeking licenses for class serve a special group in the great radio A operation. Not all these stations have audience not now furnished with what made formal application to the Depart­ they desire. In a few instances thi~ is ment of Commerce, however. This is true, particularly as some religious orders POLK'S REFERENCE BOOK not a requirement and is seldom the usual are not on the air in certain sections. FOR DIRECT MAIL ADVERTISERS Show, how to Intreoue ")lour busln!$! b7 method of procedure. Ordinarily, a All Europe, it is pointed out, has not tho UIO of Dlr•• t Mall Ad.enlslng, 60 page. prospective broadcaster first leases a so many broadcasting stations as there full or .HaI bulln." faeu and llgurts. Who, where and bow lDan7 pr05perts YOU bare. site, then buys expensive equipment are in the U nited States alone. When O•• r 8,000 lin.. Of busln.,. -' Indu...... 1 High Bchool ...... •...... DaYton. Ohio 270 ~'ictn&,~apri~~Y ChN::: ~::::::::::'.::'.:: ::: ~::'.'.: : : : ',:: ·.~~'Cb::-"o~~~~ ~:~ WEBW Bot-loitCollell:'e ...... , .. , .. , ...... •••.•.•••••.•...•.•. , . .. Beloit " 'is. 283 ~~!{l AlabamG PolY,echnic Institute .. . . , ...... Auburn. Ala. 250 WEEl The Edi.,on Electric IllumJna.tin&' Co. , ...... •...•... , ...... B ());ton. M us. 475 WMAY KincshiR'hway Pre.1bYt~riao Chureh ... . •• , ...... 8t, Louit, Mo. 280 285 WMAZ ~~~~ Ar.i :A';'·e·r i~ . ~di~ ' c.;~~'r~ tj~'a·:: :::::::.-.- ::::::. ',~~~.i~~i~~:'~·riil~~ 266 WMnn ~i~':n ~n~llei:~~ '.'.'.:'.:'. '.:',:::',::::'.::: :::::::: : : ::: : : : ~~a~::;.. ~ii : ~:~ WEW St. l.oui, Una\'~tlIitY . . .. " . ., ...... •...... •... ,St. I.ouilt. ~lo. 280 WMBF ...... Miami B.aeh. Fla. 384 WFAA D a ll D.'ll N'!w~ & Dallas JOuToal , . , ••.•...•..••. , .•. , ... , . . DaJ.lM. Tez. 472 WMC Commercial Appeal ...... , ...... •.• .•..• . . , • . . • Memphi.e. Tenn. 503 WFAM Tim'!'> PubIishint.' Co.. , ... . . , ,. , , , ...... , ...... , At. Cloud, Minn. 273 WMCA no~el McAlpin (Greeley SQUllI'e not~ l CoJ ...... New York City 341 WFAV Univerl'i itYof N<"hra.."ka. . I)cDQ.r tmf'Dt of Electrical En.-inrerin&'. Lincoln, Nehr. 275 WMH AilUl'R'orth·Gate!' RA.dio Co•. .••.• . .•.•.. . .. , . ... , . .. , . . .. Cincinnati, O . 321 WFBB Eureka. COlle.:(' . ... " .... . , ...... •. ...•. , ...•...... •• . ... Eureka, nl. 240 WMU Doublcdsl'HiIl Eloe. Co .. • . •••.•..• ..••. • .••..• . . . .. 'Washington. D. C. 260 WFBC Fitllt B~rtiti'l t Church "" ...• , .•• . ••• . •.•• . .•.. , . ... . Knoxville, Tenn. 250 WNAB The Sh.pard Storaa, ...... BostoD, Masl'J. 250 WFBD Getbsemnne Sapwt Chureb ... , . , ... . •... , ...... • ' .... Phiiadeipbulio. Fa, 234 WNAC WFSE Joho V.n De Wane , . , '" . , . , .. '., ... ' ...... •••.• ,., • ,SeymOuT. Ind. 226 WNAD t~i~~:~~t~t~fOk' l~h~~~ :: :: :::: :::: :: ::::: : ::: ::::::::: : ~~:~~ : '8~ : ~~ WFBe Tho Win. F. C.bl. Co...... AI""'.a. Pa. 261 WNAL Omaha Central Hi«h SCbool. •.. •..•....• ..•. .. • .••••• .. . OmAha. Nehr. 255 WFBH Concourae RadioCoporation . •• , ...•• .. , .•• .• ' ....•..•... N.wYoTk, N. Y . 273 WNAP ,,'ittt'nber8' COltell:'e ., ...... , ...... Sprinafiold, Ohio 271 WFBJ RtJobn·3(;ni"<-niity .. , ... , ... , ...... ••.. . ColleReviUe, MiDn. 236 WNAR WFBQ Wynne nad;o Co...... Raloigh. N . C . 255 WNAT ~~iJtC~:!~~ &~r(Wr~d~ ~ic'k t:.,'n'rtiK): :: :::: :: : :: :.: : : : : Phiia~~:!ri'g..'f.: : ~~: WFBR . Fifth Inf. Md. Nat" Guard, 5th Re«. Armory . •. .• , ...... B,.ltimorll, Md. 452 WNAX Dakota Radio ApJ>1ratua Co...... YanktoD. 8 . O ..k . 248 WFBW AiQ.·j'wotth ~ G4te.' RadioCO . • ...... •...... Cinf'inn!l.ti, Ohio 309 WNY.C Dept. of Plunt .. nd StrudUtN . • .. , .. , •• •• . •..•• . . , ..•.. New Yotk. ,N. Y. 626 WFBY ~i.gnal Offieer • . , ...... ••. .•...... , ...... , .. . Ft. Ben Tlarrison.Ind. 258 WOAC WFBZ Knox Cotle:::e " . .. , . , , ... . , ...... ' , . . .. • . ... . , ...... , Gfl-It",,,hurf'!. Ill. 254 WOAE ;;i~ln~~fco~.;e·,: ·.: '. ., ~::: :: ::::::::::: : : :::: ::: ::: ::: : F'r~~~~~'J>etl~ ~:g WFI Atrawhridce and Clothier .....•. , ...... ' ...... •..... PMJndelphiA. Pa. 394 WOAe A['IOUo Tht!ate'r (Bt"lvidcre AmlUement COJ . .••..•... .• . Belvidere. IU . 274 WFKB Francia K. Brida:mAn .. , . •. . •••.....•..•.. , ....••.•• , " . . . . Chical'o. fn. 217 WOAI Soutbcrn Equipment CO __ ...... , .. ' .. ' . . .. . , . . , • " .. SBn ADtonio. Teb..'t 392 WFUV G . Pear:o;()o Ward ...... •••.. •..... , ...... •...••. . SpriDlitfield, 1\-10. 252 WOAN Vaua-bn Conservatory 01 MU.!Iic (James D. Vauchn) .. •. LawrenceburK, T8Dn. 280 WFUW Earl Wil\;am Le.,...... Moheriy. M o. 233 WOAO Isradion MfR'. Co. .. , . .. , .•...... •.. . , ... • ,., ... , Mi&bawaka. lod. 369 WGAl I.ant'a.dt'r Elrctrie Supply dt Con"trUdion C() ...... , . Lancaster, P a. 248 WOAR I.undako.. . aonry P ...... K.,.OlIha. Wb. 226 252 WOAT BoYd M. ilalnp ...... Wilmi.Kton.DeI. 360 ~g:~ J:::t~o.~"..'J1 Trih~~~ ··. · ...... : .... : .. : .. : : '.:: ::: :'.::: ::: : : s;,~~h"~rl~ ' I~d : 360 WOAV PrnD!JYlv.ani& Nati()na.l Guard, 2d Battalion. 112th Infantry. , • • Eri •. Pa, 242 WGBB HarrY 1I. C a.r man. 217 Bed,rll St. , ', .•..• ...... , •. , ..... Freeport, N. Y. 244 WOAW W'oodmf'n of the World . . , .. , ...... , Om-.ha. Nebraau 526 WGBe Fint naptie:'~', .~~ ~ . : :.'.-.-.'.-.-: :.-.-.'.':.-.-: .-.'.':.-::.-.' : p;,.::::~N~;..1j~r':;y ~~~ WGBI Frank 8 . l\.1~l'art;'ee . •.•...... , " , ., .•..••..•...... •••.. • . Scranton. P". 240 WOI Iowa BtateCoUei:C •••• , ..••.•.•.••..•.• ' •.•.. • ..•.•.•...... Amos, I • • 207 WGBK I.a wrence C .. mphell ., .• , •...... • •.••.•. '" .••••••.•• " , .JohMtown, Pa. 248 WOO WGBM Theodore N . BaatY. .... , ...... ,' ...... , Proddenee. R. I. 234 WOR i~Ba~~~~~~::i ' C~: .· ::.',-.': .': .': ::::.':: .' .-.':: : ....::.- .' .' .~~:~t~N.P~ : !: WGSL f:1yri:\ R Adio A .... o . CA lhert Tl . Erne!) •..•.... ' •.•• •.• , .. , . . , . Elyria. Ohio 227 WORD Pf'Ople...... Ch.tl.. to •• W. Va. 273 W C N The Trihun.. Co. . , .• ...... ••.••.. •.•.•• . •.• .... • . . , .•. , Chicaco. Ill. 370 WI'G Tht! Municirt&1itY 01 Atlantic City ...• ....• •. •. : •... . • Atlantic City. N. J . 300 319 WQAA ~g~ ~~~:~~I TF:I:~ 6~.~ :·. ·. ·...... : ...... :: ....., : .. :: ...... ·.8cl.~~:c~t; ~ : i: J79 WQAC ~~B.Gi!· .. ~~l.~• ••J .r::::::::: :::: ::: : : ::: ::::::::: : : : :~A~~~~~Te!!; ~J~ WHA UD.h.-en.ity of WitcoD."in . . .. . , ..•.•...•..•• , . . " •..• . . , Ptladi.4on. "Pi", 5J5 WQAE .Moore Radio NeW3 Station (F.dmund B . Moortl) ...... •. • . Springfield. Vt. 275 WHAD M "Touette Univel'llitY ...... ••....• ...... MilWf\.uke •• Wi'J. 280 AM F.lt'rtrieal EQuirtment Co ...... Miami. Fla. 283 WHAC Uni"el'lllitY of Cincinnati .•. .• , .•••• , .•...••...• , •..••.. Cincinnati, Ohio 222 W8W AN Scranton Ti~ ." ...... • •. . •...•..• .•.. .•. • . •. . Berft.ntoc. Pe. 280 WHAH Haf.r ~upplY Co...... •. . • .. •...... • ... ..•..• ...... Joplin. Mo. 28J WQAO Calvary Bapt;". Church ...... New York. N. "(. 360 WHAM Unh'enitY of Roche.o;ter (E&l'Jtman School of Mu~ic) .... . , Itoehe... ter. N. Y. 278 Pri.nt'e-Waltt!r Co ... . ••...... •.• . .. ' •.• • • .•....•. " Lo ___ ll I\.t..... 266 WHAP II. Alvin Simmon.•• 290 Flatbu.b ATe ...... Brooklyn. N . Y . 240 WW8AS J Calumet R~inbo Broad("utinK Co ...... Chie.CO. n1. 447 WHAR SeMide nou~e .... , ...... , .. , ...... Atlantic City. N . J . 275 WRAA The Rica In. .. ritute ...... •.•.•.•• • .....•.•.. ..• .•...•• .•. . nouetflD.. Tex. 25. WHAS CoOuri"'r~JournR.1 &. Loui"l"illeTime." ", ..... •...... , ' , Lou&'H'i1le. Ky. J99 WRAF Th. Radio Club (I.e.> ...... Laport • • Ind. 224 WHAV WUminr:ton Electrical SDecinlty Co...... •..•...... Wilmincton, Del. J60 WRAK EconomY Light Co. . ..•.. ' " ' . , .. .•...... • , ' . . . . ' .&eanaha. Mich 256 WHAZ k .. nslI.laeor Polytechnic In... titutf' . .• , ...... , .. , ....•.. , . . ,. Troy, N . Y . J85 WRAM l.ombard CoUe«e ...... • .. , ...... • . " ...... Gale"burlt, IU. 2« WHO S'tftenlBY School Co ... . . , ...... Kan!lo..,. City. Mo. 365 8t. Louu. Radio Service Co...... , ...... , ' .... St. LolWi. Mo. 263 WHBA C. C. "hAlfer ...... Oil City. Pa. 250 ~~~ WHBB Hoh .. l·! Store ...... , ...... •.... 8te'·8Il!I PoiDt, Wi~. 240 WRAW ~!~~ 1f:~~~Sb~;p ·(H';;~~.· 0: 'G~ ('l j :: ~::: : ::: : :::'e.. ~.~ . ~:~C~I',O~~~ ~~i WHBC llev. E . 1'. Graham ...... Ctu>ton. Ohio 245 WRAX J-luon'~ G8r~ ... "., . . . •. . , •...... • . . Glouee."Itf'r CitY, N . J. 268 WHBD (;has. W . Howard .. , ...... • ..•..•..•..•..• .. • ..•. . •.. ReU .. fontaine. Ohio 222 WRBC Ims.nuel Luth .. ro,n Church . ...• . .•.•...•..•. • ...•. , " , . . Valparai"o, Ind. 278 WHB F lHID.r~leY SDeeia.lty CompnnY . .•...... •..• Rock Island. Illinoie 222 WRC Radio CorP. of Am...... : . •. WQ..'IhlO.:ton. D. C. 468 WHBC John. 8 . SklLne , ...... •....•..•...... •...... Ha"&.,.OOTII, Pa, 231 WREO Reo "Iotor Car Co •...... , ...... ••.• .•• .•••... , . ' . " . La.n."Iin.g. Mich. 286 WHBH Culvf'r MiIit!1. ry Aca.deruy • .•• , •.. , ..•.•...... • " . •. . , . . Culver. Ind. 222 WItHF W&!hinC'ton Radio HO!'IPito.l Fund •...... •. . •• •••... .• .. W a..; hiQl'toD. D . C . 256 WHBI Chello,nin.C' Elertric Co ...... •....•..••....•. , . ..•..• . Cheaaninl', Mich. 227 WRK t WHBJ LeLuer Auto Co, ... , ..... , , .. . •..••.... •...... ' . . ' . ,. , , Ft, Wayne, Ind. 2J4 WRL B~i~~ ~i:ir·e· . '.', ' ...... , .. ',', ':•... : .. ,,::.,. ':.'::.:. ·::: . · :::::.· :Schel!:~I~~. N~~~ ~;: WHBK FrlUlklin St. G arl!t.i!e. Inc ...... •.• , ' ELL"Iworth, M1I.itle 2Jl WRM UniveQiity of IllinoiA ...... •.. . .••••...•..•. , . . • . . Urhana. III, 273 WHBL J3.me!t n. R\u.s :OO f'r . , ...... •....••••..•.•.•...... •.••.. Loc~n !t port , lnd. 220 WRR rollee n.nd Fhe SlImal Department . .. . •..•..•. . . .. ' . , . , . . .. Ds-I""", Tex. 261 WHBM C. L. C~rron. Portrlhle A'Atinn . .•....•• . .•.... ,. , ..• , .. , " .. Chica go. Ill. 2JJ WRW TarJ'YtOwo Radio Re.,. Lab...... Tarrytown. N. Y. 273 WHBN Flf'JIt A\.'p' . M"thodUtt Churdl . . .•. ..••. ...•.•... . 8t. Pet t!rll burc, F10ridft 258 WSAB South~a.qt Mi.... " ouri Sta te Tt!&chcn CoII~~e . ... • •... ..• . Cap~ Girardeau, Mo. 275 WHBO Y. !It. C. A .• 1'Iummer Stroet. ..•• •. .•...••..•. " . P ... tllck.t. Rhode r. land 2JI WSAC CI."",on Agricultural Collece ...... CletNIon CoUoca. S. C JJ6 WHBP Johl\.lltown Automobile Cn . . , . •..•• . •• , .••.••.. • JObaDtOwn, PenDlYlvania. 256 WSAD J . A . FOIitt"r Co...... " , ..... , .. . , ..•.•• .• ...... Providenc~, R. I . 26. WHBQ St. John', ~f , E .

ASHINGTON:-That advertising is the Interstate Commerce Commission W insidiously creeping into broadcast should take a hand, claiming that tele­ programs and that radio "en tertain­ phone lines are a public utility or that ment" wiII eventually become "thinly connecting lines are between states. veiled publicity," is charged by some of Statements from a number of the rep­ the leading exponents of radio and resentative manufacturers show that ad vertisi n g. there is no unanimity of opinion against We have all heard what are virtually paid radio advertising, but they all publicity talks on coffee, candy, flour, believe in good broadcasting. chewing gum and other commodities, Lee DeForest believes that as more through the air, and also enjoyed en­ concerns take up radio advertising, their tertainment by playing-card quartettes, programs become less interesting to the au tomobile-tire orchestras, safety razor public, tha t advertising is insidious and and grocery store musicians. The butch­ becoming more flagrant; and he asserts er, the baker, the candlestick maker and that he has actually become prejudiced the whole of industry has been broad­ against several of the broadcasters' casting of late. What is it coming tol products. He looks forward to a time The question "whether advertisers when the great majority of programs will should pay for broadcasting" is causing be for "thinly veiled advertising pur· concern among the broadcasters and poses." national advertisers, as well as the radio Secretary Hoover is opposed to censor. industry itself, but since it will be up to ship, but through the radio conferences the fans to decide eventually, a brief of it has been made known that "indirect a survey recently made by Albert E. advertising" only is permitted via broad. Haase follows: casts by The Department of Commerce. However, Mr. Haase sees possible Gov. Radio and Business ern mental inten'ention and ultimately "The radio industry is discovering that a decision from receiving set owners. good broadcasting means good business, Views of concerns which have tried and extraordinary broadcasting, extra- paid advertising are interesting. The ordinary business," Mr, Haase points out. Eveready entertainers, considered unique "Conversely, poor broadcasting means by many, actually pay the National poor business. Many who are in the in- Carbon Co., in good will. One day 3,000 dustry realize that if the mad rush to letters came in, according to J. R. Craw­ he FIVe Tube get the advertisers' dollar for the support ford of that company. But he does not of radio continues, radio itself wiII suffer. think radio advertising, even indirect, TS~t WhiCh! Today, advertising agencies are offered would pay all types of manufacturers, 15% commission by a number of broad· except experimentally. startled casting stations for business. One sales- As a contrast, Stuart Peabody of the man has secured the advertising rights Borden Milk Co., claims that two broad. * the World from fifteen stations. casting trials failed to bring adequate "On the other hand, stations which responses. The l\Iacy Co. failed to do not sell space on the air are besieged derive substantial benefits from broad- by publicity men who seek to talk on 1\ L certain business and collect from the casting. But ,at ewis, owner of two C~nRP1~~ manufacturers. gift and haberdashery shops, found fashion talks via radio, which he calls "Overdoing advertising, will kill radio ~'publicity," better than some other forms TL~ Greatest Value and at the same time hurt advertising, a of advertising. He received 5,000 letters representative of the Colgate Co., is following one talk. Ever Offered in A Quoted as saying. The whole problem of radio advertising is being studied by the Officials of the United Retail Candy Radio Receivin9 -Set _ Association of Advertising Agencies, Stores, backers of the" Happiness Boys," which already has decided that the say after fifteen months of broadcasting At Authorized Dealers : present methods of radio advertising are entertainment stunts, that they feel it is not agreeable nor desirable to fans, and "publicity" rather than "advertising," that the nuwise use of radio advertising which they use simultaneously. will be bad for all advertising." The Fisher Co., Astor Coffee manu· PWX So far the American Tel. & Tel. Co., facturers, continue radio programs after through WEAF and a chain of inter- fifteen months' trial, having received over connected stations, appears to be the 100,000 communications from all parts of main channel for radio advertising. The the country. charges according to Mr. Haase, vary Through co-operation with the A. T. from S2S a minute for talks, and $250 a & T . Co., the Victor Talking !'.Iachine half hour for entertainment, from one Co. is said not to pay for space, when its station, up to $1,600 an hour for enter- stars sing and play. It is studying the tainment distributed through seven sta- results, however, and will soon report on A 62-page tions. The advertisers, of course, furnish broadcasting. Advertising experts feel Blueprint Section all the talent. Circulation is part of sales that radio has a time limit and that its I talks, but figures are naturally only circulation is uncertain; compared to in the August estimates. These rates are not guaran- other mediums; they believe it is prob­ RADIO AGE teed as fixed, b ut may be increased, unless ably an accessory. ¥- Tested and Approved by RADIO AGE ¥- 68 RADIO AGE/or July, 1925 The Magazine 0/ the Hour

WSMB 319 WTAU Ruegg Ba.ttery &: Electric Co...... , ...... TOC!umseh. Nebr. 242 WSMH ~~~:~k A~=~R:~c:. · . ~~~ . ~~.o.~ .~~~~.f)• •~. :: : : : : : .~~Ow~e:ruMi~: 24D WTAW Acriculwral ok Mechanical CoU~n 01 T.xao ...... Coll.... Btauon. TeL :280 WSMK s. M . K . Radio Corp . ...•....••...••...... •.••...... Dayton. Ohio 275 WTAX W'illiama HardwfU'e Co.,. . , ... , .....• . •..•...... •. Stroator. m. 231 WSOE School of Emrinoeri..n.c . ... " ...... Milwaukee. W ... 246 WTAZ Thom!U J . McGuir • .. . .•...... , . I.mhert.'riDet N . J . 283 WSRF Hardem. S 31e" and Service ...... Bro..'ldlar:ub. Ill. 233 WTHS Flint Senior Ilicb School . .. . •... _ .•...... • . .. .•...... •. . Flint, Mich. 218 WST A Ca.mD Maritnfeld ...... _, ...... •...... •.. CbMham. N. H. 22~ WTC K&n.M StA .... ~cul.uraJ CoU.... . _ .. • ..•..••.•.....•• M_nan. lI:a.no. 273 WSUI State Unit"e ~it.y of Iowa ...... •. ' ...... • . . Iowa City. Iowa 498 WTIC Travelen WUT&.AC~ Co...... •.. . •...... Hartford. CoDD. 323 WTAR F all Ri'f;"f'r Daily Rer",1tI Publiahin2 Co. ..•...•...... ,Fan lti.I!;T. Ma."Ut. 248 WTX H . G . Sr\l'll ("JOO •• •••••• • •••••••••• • •• •• •••••• ••• • ••••••• •• • • Cbil\A&:o, m. 268 WTAC PeDll Traffic Co. . _. .. . •. . •. _ . . _ ...... •...... Johnstown. Pa. 360 WWAD Wright'" Wright aneJ ..... •• ...... •. .. . Philadelphia. Pa. 360 WTAL Toledo R.d.io & Electric Co ...... Toledo. Ohio 25Z WWAE The AJa.mo BaU Room ...... •...... •...... Joliet. ru. 242 WTAP Ct.mhridc. Radio &:. E1eetrie Co.. .•...... ' .. '" •. . C.mhridc•. IU. 242 WWI Ford Motor Co...... Dearborll.. Mich. 273 WTAQ S. B . Vaa Gordon & SoD • •• • ••.••.•••••••••••.•••••••••• •• • 0 93e C), WL'. 22D WW.J Detroit News (EveniD« New. Asao.) ...... Detroit. Mich. 352 WTAR R.e.1i.a.nco Electric Co...... •.. _ .....• . , ... . • . • .. •. , . . , _ .. . Norfolk. Va. 2M WWL LoYOla Unh,-ehity...... • .•...... , •.••.....•. . New Orlea.na. La. 260 WTAS Cbarle. E. &b:st.ein ...... _ ... , ..•... . .•...... •..•...... Elgio. Dl. 303 WWOA hiicbiaao Colle~e of Minea . ..•...... •..•. .. , ...... Bou«hton. Mioh. 244 WTAT Ediaon Electric Illuminating Co ...... {porta hI.) B08toD. Ma...... ,. 241 Canadian Stations CFAC Cal,..", B.'ald • ...... •...... Calea",. Alberta 43D CHXC J . R. Booth ...•. . ••.... • ....•.. . .•...... •..•...... Ottawa. Od. 435 CFCA Star Pub. k Pr1.g. Co...... " . •. ' ....• , ...... •. ..• . • . Toronto. OJ)urio 40D CHYC Nortbero Electric Co...... , . . . . . MODtreal. Quebec 410 CFCF Mucooi Wirelf!Sll Teleg. Co. Ca.nada...... •...... " . .. MoDtreaJ. Queheo 44D C.lBC Jarvi3 BAPliat Church ...... •..•...... Toronto. Ont. 312 CFCH 400 C.lCA Edmonton J"Ourllal ...... •..•...... •.•. .... Edmontoo. Alberta 455 CFC.I ~~i~~! ~~wL~E~e~:~~~: : :::: :: : :~::::: :::::: :: ::: : ~~~Q::~~'u?~~ 410 C.lCC LoDdon Free Pre..Y Prt.a:. Co ...... , ...... LoodoD. Ont. 430 FCKC RacUo SUDPly Co.. . . _ .. ' •...... • ...... '.' • .... ' . .. Edmonton. Alben. 410 C.lCD T. Eaton Co...... •...... • ToronlO. Onto 410 CFCN W . W . C".nt Radio (LtdJ ....•. .. •..•...•...... Ct.l""r>'. Alb ...... 44D C.lCE Snrottr8haw Radio Co...... Vao.couver. B. C. 420 CFCQ Radio Bpecialti.. (LtdJ •...... ••...... •...•...... V ...eouye,. B . C. 450 C.JCF The Newe Record . .• ...•...... • .• ...... , ...... IGtche.aer. Onto 295 CFCR Laurentide Air Service ...... • ..••.••...•..•...••..•.. SudburY. DDt. 410 CJCI Maritime Radio Corp ..... _ .. •.•••••..•.•.•. • • . SL JobD. Ne.". Brunswick 400 CFCT Victoria City Temple ...... •... . .•.••.•...•...... Victoria. B . C . 4\0 C.lCK 316 CFCU Tbe Jack Eltiott Radio Limited ..•...... Hamilton. Oat. 410 C.lCM IJ:"top~ull'.;. ~~ . ~~~: ::: : ..::: .. :: .. :::::: .. ::::: : ::: : M~~~~~ry6u~~ 430 CFCW Th. Radio Shop ...... •...... •...... London. Onto 420 C.lCN Simon! Agnew &- Co ...... Toronto. Ont.. 410 CFDC BPI',ko Co...•...... • . .•...... • ...... Nanaimo. B. C. 430 C.JSC Et'eniDc Tele&'ram ...... • _ ...... •. ' . .•• ' ...... , Toronto. Onto 430 CFHC Ue..". Birks & So...... Calean-. Alta. 440 CKAC I. Pressc Puh. Co ...... ••.. Montreal. Quebeo 430 CFLC Cbas. CUy Hunter ...... •.. 6051 Adelaid., St.. Loodon. Ont. 410 CKCD Vancouver Dally Province ...... ' ...... ' ..•...... Vaocouver. B. C. 410 CFQC The Electric ShOD (Ltd.) ...... S&!Ikatoon. 8ukat.cbewl5.D 400 CKCE C .. nadian IDdepend. TelePboDe Co...... " . . Toronto. Ont. 4SO ' CFRC Queel15 University . •.. . •.•.• ...... ••... _ ..••. •• ...... KiD&'Stoo.. Ontario 450 CKCK Lead., Puh. Co ...... •...... •...... R.gina. a... katch...... 420 CFUC Univenity of Mootreal...... •...... •...... • . . Montreal. Quebec 400 CKCO Ottawa Radio Aeociatioo ...•...... ·. Otto.".a. Oot. 440 CFXC Weatmi.ll.'Iter Trust Co...... _ ....• _ .••. . .• Ne.". Weatmiluter. B. C. 440 CKCX P. Bur ... '" Co ...... •...... ••....•...... Calcar>'. Albe"" 440 CFYC Victor Went.".orth Odium ....•...... , ... . VaDcouver. B . C. 400 CKLC Wilk,in.son Electric COmp&nY' . . ..•...... Cals:uy. Alberta 400 CHAC Radio Enl:'ineers ...... • ...... Halilaz. Nova Scotia. 400 CKOC Wentworth Radio Supply Co...... •... . .• ...... Hamilton. Onto 410 CHBC Albertan Publishing Co...... Calgary, Alb.rta 410 CNRA Ca.nadiaD National R .. iJ.". .. YII ...... Monctou. N. B. 313 CHCB Mareoni C.-omp&DY ...•...... •..•....•.. .. .•...... Toronto. Ont. 410 CNRC Canadi$n Natioud Rail .... aYII ...... , ..... :. . ..•...... Cals&I'Y. Cana"da 357 CHCD CanadiAn Wireless & Elec. Co...... '.' .•. . . Quebec. Quebec 410 CNRE CUadian National Ra.a.".aye ••• • .•• ••••••••• •• • " ••• ••• ' . Edmontou. Alc.a.. 455 CHCE W .. ~", Canada Radio I3uD . (Ltd.! ...... •...•••...... • .. Vietorio. B. C. 400 CNRM Canaw.n N ••i Ollal RailwaYIJ ...... ••.•..•...... • . Montreal. P . Q . 410 CHCL Vancouver ~lerch&DLs Exchange ...... •..•...... Vancou,,"er, B. C. 440 CNRO Canadian NationeJ Rail.".a.va .. .•...... ~ ...... ••. . Ottawa. One.. 430 CHCM Rney &- McCorm.a.ek ...... " . . Calga.ry. Alherta 415 CNRR CanAdian National Railways ...... •...... RelD..o.A. Hub. 31Z CHCS The Hamilton Spectator ...... •...... Hamiltorl. Onto 420 CNRS Ca.na.dja.o N&tiOllal RaiI.".an .. .. ' _ . .•. ..•...... •• ...... S.a.ekAtoon. 8a.sh. 329 CHIC Northern Electrio Co...... _ . . . Torontn. Oot. 356 CNRT Canadian Natioo.al RailwaYs ...... •...... Toroll.to. Oll.t. 357 CHNC Toronto Radio Research ...•...•...... •...••..•...•..... Toronto. ODt. 350 CNRW Ca.na.dian National Ra.ilwaYB ...... •...... •. ..•.. " ...... Winuipe&'. l'tian. 384 Cuban Stations PWX Cub... TeI.phon Co. • . . • . ...••..•...... •...•...... •.....• B.bna 400 2K Alvar& Daze . • • ..•... . . •.. , . .•..••.. . .••.•.....• • •.. .•...... Babana 200 2DW Pedro Za7...... Bah... 309 2HS Julio Power . ••.. , ...... •...... •..• . . .. , • ... •...... ••••. • •. Hab&na 180 2AB Albe"" B. d. Bu.tamallt41 .••.•..•••.•...... ••.••.•... • .. . •.•.• . B.b...... 240 20L O.ear CoUado •• ..•• . ••• • •..•...•.••.•• ..••.•...... •. .• •. • • • Babal>a 290 20K Macio Carcia Veles ..• . •. . •... . .•...... •.••••. • •..•••••.•• . . Hahana 360 2WW Amad..,B ••= ...... _...... HahAAa 210 2BY Frederick W. Borton . •....•....••..•.•. .• • • •• _. _ ..•.•••..•.••.•. Kahana 260 5EV J...eoPDldo E. Ficu.ro& . • .•. .••...... ••...•• . • . . .. •...• . .•.•.. . c.olon 360 2CX Frederick \V. Borton .•...... •.••.•....••.••.••••...... •• .. .• .. Hahana 320 6KW Frank; 8 . Jone!t • •. •...• . ••..•. .•. • .. .••• , • .••.••... . ••.••. . .• TuiDuou 340 2EV W .. tinI

January. 192.. SePtember, 192.. Fehru...... , 1925 -Tun~ Out Inl.erfer6nc_Wave Trape-Etimin.&tore - How Careful l\.fountinz Wiu Imorove R eceDtion. -A Slm! Shot Super-BeL -Til...... -A Tbre

Dry Cell Tests Held Stewart-Warner Radio, Freshman Announces New for First Time Mode130S Sales Policy N May 10, from the Great Lakes The Stewa rt-\Va rner Speedometer Cor­ The Chas. Fresh man Co., Inc. of O Naval Training Station, Great Lakes, poration, 1826 Diversey Parkway, Chi­ New York has just announced its III., the first tests in history were made cago has placed on the market a com­ sales policy for the coming season. This from an airplane in flight, using the new plete ensemble of matched radio units. concern, manufacturers of the line of This ensemble consists of the line of Freshman Masterpiece Receiving Sets, 37 meter radio transmitter and receiver Stewart-\\'arner Radio Instruments; the has decided to eliminate the jobber and operated by dry cells only. Stewart-\Varner Reproducer especially distributor in the sale of their products. Heretofore, all airplane radio equip­ built to give perfect harmony with Stew­ Fresh man l\lasterpiece Sets will be sold ment has had its source of power from a art-\\'arner Instruments; Stewart-\Var­ to Authorized Freshman Dealers, care­ small generator which was driven through ner Radio Tubes, designed to give beau­ fully selected, and granted an exclusi ve a fan-shaped propeller by the force of tiful tone quality; l3atteries, Aerial and franchise in their territor)'. In towns of the wind. In other words, when the engine Ground Equipment. approximately 25,000 and under, one representative (icaler will be appointed and the airplane were out of commission to exclusively handle the line, and in -so was the radio. This new transmitter larger cities, additional dealers will be which is being tested is the first of its granted franchises in proportion to the kind and is one of the transmitters which population and trading area. ..\ staff will be used by the l\1acl\liUan Polar Ex­ of salesmen is now at work signing up pedition which sails from Boston, Bun­ dealers to the Fresh man l\lasterpiece ker Hill Day, June 17, under the auspices Contract, which assures dealers of abso­ of the National Geographic Society. lute protection, as far as stability of prices is concerned; also, all business from each The value of this type of equipment can indi vidual dealers' territory will be credi­ be immediately realized when it is remem­ ted to him. In this way, the appointed bered that the airplanes that are to ac­ dealers will be practically direct factory company the l\1acMillan Expedition representatives of Freshman. manned by U. S. Navy p~rsonnel, under The Stewart-\Va rnt!r Instrument shown The Freshman Company enjoyed re­ the command of Commander R . E. Byrd, is Model 305- a five tube set in which markable success with their one model, is incorporated the U. S. ~ayy Circuit. the original Freshman ~Iasterpiece, dur­ U. S. N., will fly over that great unex­ There are three tuning controls, mounted plored area lying between Point Barrow ing the last year. The fact that with one on a sloping front panel. The cabinet model, priced at $60.00, Over 125,000 and the North Pole, in quest of new land. is finished in dark walnut. sets were sold from July 1924 unt il Feb­ Should a landing be forced, this type of In this instrument, the special Navy ruary 1925, speaks highly for the tre­ apparatus, if efficient, will be able to tuned radio frequency circuit has been mendous hold this product has taken communicate after the airplane itself is developed to a high stage of perfection, with the radio public. With the realiza­ out of commission, and the flyers wiII be and the set is especially suited to opera­ tion that the trend in radio buying is able to call for help from the planes held tion by men or women without technical leaning strongly towards furniture effects, knowledge or training. the company has placed a complete line in reserve back at the advance base of The Stewart-\Varner Reproducer is Axel Heiberg Land. of Fresh man l\Iasterpiece Recei"ers on built by the Stewart-\Varner Speedo­ the market, ranging in price from a The Zenith Radio Laboratory an­ meter Corporation of Chicago, especially Five Tube Radio Frequency Set, in a nounced that the tests made at Great for use with Stewart-\Varner Radif) In­ massive cabinet with sloping panel at Lakes Naval Training Station on 37 struments. This Reproducer is so de­ $39.50, up to the Franklin Console, a meters were not satisfactory, as the great­ signed and constructed that it covers the dignified piece of furniture of vigorous est distances at which they were heard entire musical scale with full, rich tone lines and fine proportions, made entirely were Newton, Iowa, and l\Iinneapolis. "olume and without distortion or scratch­ of genuine solid mahogany by the manu­ ing noises. The horn is made from fibre Failure to reach greater distances is facturers of the highest class t a lking by special process and is "ulcanized on machine Comllany in the world at $1 i5. attributed to the fact that the amateurs its outer surface. The core of the horn The Franklin Console is composed of two of the United States were not properly is allowed to remain soft which absolutely separate and distinct units, one of which advised of the time at which these t ests pre"ents the horn from vibrating at is a rccciy inl!" set with built-in loud would take place. any note. _ speaker, anti the oth.er the cons?le for The Stewart-\Varner Reproducer is batteries a nd accessones-everythmg be­ finished in a dark walnut, leather-like ing concealed. Campaign for Jewett surface, and stands On a metal base which is deep green with gold-bronze high­ .H. WILKINSONandT. F. \V. Meyer, lighting. This Reproducer harmonizes New "Hercules" Masts General Mana~er and General Sales E perfectly with the walilUt cabinet work \Y. HULL & Company, 2048 East Manager, respectIVely, for the Jewett of Stewart-\Varner Radio Instruments. Radio and Phonograph Co., Pontiac, S • 79th St., Cleveland, Ohio, annOl'nce 1lichigan. have returned to the factory a new 'series of .. Hercules" Aerial l\last. after an extended trip through the East These masts are made in three standard putting the finishing touches On the new come well recommended as to their sta­ lengths, 20 ft., 40 ft., and 60 ft., all steel distributors' and dealers' franchise plan bility by a Jewett Distributor, or one of construction. in that territory which has been under the factory district representatives in the way for several months. All masts arc made of a special angle field, it is announced. construction that gives great strength The Jewett slogan, "Fair prices, ril;'idly The dealer will be benefited in this maintained" must be very strictly same respect by knowing that his cus­ and light wei~ht, thus making a rugged adhered t o under this new system, be­ tomer cannot buy a Jewett product from mast easily erected, at the same time cause every dealer handling Jewett any but another authorized dealer who presenting a pleasing appearance by its products throughout the country must is holding to the standard Jewett prices. graceful lines. (Tum fo page 72) 70 RADIO AGE for July, 1925 The Magazine of the Hour CLASSIFIED ADVERTISEMENTS If you have anything to buy or sell, don't overlook the value of RADIO AGE'S classified advertisements. Many such messages have paved the way to independent incomes. The classified advertising rates are but ten cents per word for a single insertion. Liberal discounts are allowed on three, six and twelve-time insertions, of five, fifteen and thirty per cent respectively. Unless placed through an accredited advertising agency, cash should accompany all orders. Name and address must be included at foregoing rates and no advertisement of less than ten words will be accepted: All classified ads for the August issue must be sent in by July 1.

AGENTS WANTEB INVENTIONS RADIO CIRCUITS FORDS. &0 mile. on one gallon of C... It h •• been NEW IDEAS WANTED-Well kno... n Radio Manufac- SPECIAL FOR JULY proven .u~h m.ile:age Can be made. AIRLOCK e •• r­ turer whOle productl ar~ nationally advertiled and ..,Id antee. to incre •• e ga. rnileacc ; aho prevent a radiator everywhere wantl new Radio device -to leU. Will pay !he Reina",!; Radio Booklet, by Frank D . Peame. tully boiling in lurnrner Or heoezing in winter. Cool•• FueJ.. outright or royalty for idea or invention which il really ,lIult.rate~. and RADIO ACE, tor $2.50. Price of Book­ Decarbonize. the Ford moto,. Splendid territory new .nd .aleab'e. Addrela: Mr. R . F . Devine, Room let alone •• SOc. Send check, currency or money ord.r open. AIRLOCK PRODUCTS. Bo. 703C. WHlo ... Street. 1101. 116 Weot 32nd St .. Ne ... York. N. Y. ' to RADIO ACE, 500 N. Dearborn Street. ChiCACo. Lcn~ Beach. C.lif.

RADIO-Join Our .ale. or•• nization and make bie MAGAZINES RADIO DEALERS moncy. We want" Inan in every count)' to lell well DREAMS. A magazine for aU who dream. If you adverti,ed aeU and parta made by the le.dine manu­ are interested in the .ubjecta of Icience. lez, paychology, facturen. \Videner of Kanllu City make. $150.00 health, love and romance, you cannot affo ... d to be with- DEA.lER5-Write. for our illultrated cat_lol' of reli.ble w e ekly. You can do •• well or Mtter. \Vrite today out thia magazine. Three dollar. will brins thil ",oat RadiO Merchand'ie. Roe.iter-Manning Corporation for cataloc" and d.lcounu. Name your county. Wav~ t.lcinatinR monthly pLiblication to your horne for Dept. D, 1830 Willon Ave., Chicaco, 111. • lan d Radio Company. Dlv. 52, 1027 No. State St. , Chi­ one y.ar. M . B. Smith Publilhinl' Co., 508 N. Dearborn cago. III. St. , Chical'o, Ill. RADIO SUPPLIES - MANUFACTURER'S ACENT calling on Radio-Elec­ trical Jobbe n , Chicaeo and vicinity, hal openinc for 3 MANUFACTURING FACILITIES additional linel c.al'Tyine volume bUline ... al We cater Ten per cent dileount on.1l ItandaTd radio part •• to laree jobben. Edeldein, 1804 McCormick Bid .• AN OLD AND WELL ESTABLISHED MANUFACTUR- from t::ondeneeT& to han.formere to tube-a, etc. Send Chicuo. r: INC COMPANY IN THE MIDDLE WEST WITH LARCE WELL EQUIPPED PLANTS AND UNUSUAL FINAN- (0.1' o~r latelt price Ii.t, with apedal bargainl on Static­ elam',,:aton, . portable loud .peakerl. R.diotronl, C.r­ CIAL RESOURCES. D£SIRINC TO ENTER THE RADIO man •• Io.r ...... etC. RADIOCRAPH LABORATORIES. ACENTS-WRITE FOR FREE SAMPLES. Sell Madi.on FIELD WILL CONSIDER THE MANUFACTURE AND 1234 ROHmont Ave. , Dept. 4, ChicaC'o, 111 . " Better_M.de" Shirt. for laree n.nufat::turer d iret::t to SALE OF RADIO SETS OR DEVICES OF OUTSTAND- we ... ,.er. No capital or e.perience required. Many INC AND UNUSUAL MERIT ON A ROYALTY BASIS. oarn $100 ... eekly .nd bonu •. MADISON MFCRS.. SOI ADDRESS BOX IA. RADIO ACE. Broadway, New YOT ... . STAMPS AND COINS PATENTS tOe an hour to advertile and didribute lamplt!'1 to con­ lumer. Write quit::k fOT terrltorY and particularl. FOR SALE: U. S. and Can_dian Patent on an Attach- AIn.,.ican Produda Co., 2130 Arnerit::an Buildins. Cin­ ment for Phonographa. il the moat beautiful invc.n- einnati. Ohio. t ion of the age. Add,e •• Ch... . F. Smith, HuB', N . Oak.

Man wanted for thil territory to aell wonderful .alue men'l. women'l, Children'l Ihoel direct. lav­ PERSONAL inl' conaumer oyer 40 c;o . Ezperient::e unnecee.. ry. LONEL Y HEARTS, uchangeletlerlO make intereltihc ~• ..Tt:I::d:;'.f[:~~~~a f!,if~, c:~,"i'r34~~'S: .~80':!o~~M::::: new triendl in O\lr jon,. dub. Eva Moore, Box 908, Jacluonvillc, Florid•. EncJoa•• tamp. VOCATIONS Loold You Radio Bug.r Join' Radio Correlpondence "B" BATTERIES M.ke Bia Mon.Y. Safe and ~k upert. Warna ~~~~~ng!-"i~!:I:. ."M,;.:nb!~hi!e::nu:o aLlD-vn~UGS Stronlr, 3800 Lan FTanco St •• La. AnC'eJ~, Calif • • 1.0. Dime ,tamp bringl p.mphlet and Radio Novelty 100 VOLT EDISON TYPE " B" BATTERY. knocked Ca,.dl. R.dio ROle, Bo'l: 662, Cleveland, Ohio. down. Partl and planl-.c;omplote, $12.50. Lane Mf&' . 2937 W. Lake. Chicalro. WANTED PRINTING BATTERIES FOR SALE-Four 24-oolt "M.in·· Storac. "8" Batteri•• , nev .. r \ued. Ihipped and ready to wire ~~:.~~t ~:~:::;:i~'1 ~~!~e~::ta~~:~~~~~. Circulan. for 138.00. Fir.t order Ireh the batterie.. Addrel. Bo. B. Radjo Agm, 500 N. De~n-born St., Chical'o, UI. RADIO A RECEIVINC SET FOR $10. BUSINESS OPPORTUNITY PRACTICAL TUBE WIRELESS :h~-::.i.dtu::I.:dh~::er~~11;.O~ · J. ca~~fHBwj~~ 1067 Winona St., Chical'o, Ill. WANT TO MEMORIZE THE WIRELESS CODEr The MR. MANUFACTURER : Would you be intereated in CorYden SnYde,. Code Method. Patent~ . i. quicke.at. Send 50c CClin. Itamps or M . O. to C. C. Snyder, 1.Z3 • national adverti.ina campaian to reach more than Standard .oderte .. radio Jad.... Bindinlr po.t attach- two million pro.pcctive buyere o( quality radio productl menh. Double circuit. One dollar biIl. POltpaid. EJmdaJe Ave.. ChicaEO. III. ~ach we-ek? Do you want to e.ta blilh agenciel in Clinton Seward. Jr., N.w Pa1t2. New Yotk. N. Y. new territory and cr~ate n_tional int~relt in Your product-at a very ~on.ervative ~01t7 It can ~ done. Three COen1lopolitan Phu.iformert. each $5.50, book of Let UI eap'ain our 'Yltern without obligation to yOu. inatruction. includ.d. F. A . Man. Triopli. Iowa. WRITERS Drop a card to Radiograph Laboratori n, 1234 Roeemont Ave .• Chicago. In., Boll 6. FOR SALE-3 Pfantti.hltuninC' Unila. 3 Cardw.n Con- NEW WRITERS WANTED-Articleo. otoriu, _mo' den.ere 1 Bradleyomater. 2 BradleYltah. AlIl'oodl .een."ioa, etc. $13. 500 ju.t paid to unknown writer. New. Earl Price, Lodi, Wi •• Entirely ne'" Ii.ld. (No. bunk.) NOT A CORRE­ CRYSTALS IS to 2S per cent d it4::ount on nationally ad"ertilC'Ci .eU SPONDENCE COURSE. Movinl' pi4::ture indultr)' and and parla. E.ery i tem guaranteed. Tell u. your needl. publiahera cTyit'lC' for new original material. YOU IMPERIAL RADIO COMPANY. Del..... re. Ohio. CAN DO IT. W@ buy manu.criptl for bookl and maC'_ TESTED CALENA CRYSTALS, 5~ pound bulk. Buo­ kell, Ceo]oaiet, Joplin, Mo. RADIO SETS. Our pricea .ave you moneY. Lill. fr••. :~~j:~ie. ScAtr~R~tAesT~DeIOS~o/: C:.°8c!~·~,7~ l:! The Radio Shoppe. Bo. 645. Ealt LiverPOOl, Ohio. Angelft, Calif.

HELP WANTED AT LAST The R.dco Static Eliminator. Eliminatee WRITERs-c. ... in on your knowledl'_ of radio by 50 to 90 ~ Static. Many &at jailed utera. Write for wri1:i.ng for Radto Magazine. and New.paper Supple­ particular •• Radio Spec:ialtie. CompanY, Siou. Fan • . menta. Write up Your radio npeorienre., your new RADIO SALESMEN and SET BUILDERS-We need South D.leota. hook-Up, your knowledge of bt-oadcaetinC' Itation. and YOU and you need ",e. If you .re reliable and weJl artieh. Experienced authorl will eonect _nd improve your manuacripta-rnake them typirally profellional ~:p~~!'e~~a~~~r a~dfu~::::l' ;oeu w~!t;:P~~~~:rdu :~i work. FREE Criticiem and Adviaory Service until your" adverti.e-d aeh and parh .t pric@. th.t will enable you manuecript i. toldl ALL Ma .... 2ine. and Paperl de­ to lell at a handaome profit. Write at OnCe for cata- Maybe an mendinit fiction and artide. dealtnC' with radio. Her. l:.gS~~eS:~:~~i;~gD':"ili~land Radio Co •• Div. 53, )027 i:oot?e~.R ·PJ:WOR.J:~N-Za~ tSen~!~r SM~n~~~T~~~~ Willi. Arnold and A •• oci.tol. 210 Ea.t 0"'0 St. Opportunity Chical'o. 111. • M!N wantin&' forelt ranKer, railway de... " and other government po_itiona, writr for free p.rticQlara of exanll. Mokan~, Dept. B-33, Denver, Colo. awaits You in the Make big money WTitin8' Movie Playe. Clrru'a,. free. W . C. Kruc. Aahton. Ininoi • • Radio Age Classified Classified ad. copy for the August RADIO AGE must be sent in by Section Have you ordered your July 1, 1925. August Radio Age? :f. Tested a7ld Approved bll RADIO AGE :f. RADIO AGEjor July, 1925 The J[agazine oj lite !Iour 71

ITH better and more THE RADIO AGE Wpowerful broadcasting- and with a sensitive, respon­ BUYERS' SERVICE sive Telomonic II I receiver- What do you want to purcb .... in the radio line? Let the .taff of RADIO AGE .ave you time and money by •• nding in the coupon below. Enter the number of the article you the fascination of radio con­ would like to know more about in the .pace. providrd in the coupon. tinues this year, regardless I " A., " B.tte-rie. 95 Grid leak holdere 186 Rheoll.t ••• utomatic 2 Aerial protector' 96 Grid. t.ranamittinc leeln 187 Rheo.tau. battery 3 Aerial i.n .uJ.tora 97 Grid leak., tube 188 Rheoat.tl. di.1 of the calendar. .. Aeri.l. 98 Grid leak •• v.ri.ble 189 RheoltaU, fiJ.ment S Aeriel_, loop 99 Grinder., electric 190 Rheo.tatl, potentiometer 6 AmP) ifier. 100 Ground cl.mPI 1 '1 Rhe-oetau, power Write to Danziger-Jones, 7 Arnplifrina unit. 101 Ground rod. 192 Rhe-o.t.u, .. ernier 8 Ammeter. 102 H.ndle••• witch 193 Rod., Iround Inc., Dept. C, 25 Waverly I "'B" bettene. 103 Head b.nd. 194 Rotor. 10 Betterie. (,tete ,olt.,.) 104 Head phone. 195 xraper., wire Place, New York, for book­ 11 Betterie., dry cell 105 Head .eU 196 xrew driver. 12 Baueriel, .tOr.lJ'~ 106 Honeycomb coil adapter. 197 xrew. 13 Bettary charaer. 107 Hook "p. 198 xhoola, ra dio let, "The Kit of a Thou­ 14 Battery clip. 108 Horn •• compe.ition 199 Set•• receivinB-<.binet 15 BatterY pl.te. 109 Hornl, fibre 200 Setl, receivinlJ'-"'Cry.tal sand Possibilities." 16 Satten .ub.thute. 110 Horn., mache 201 Set., recei .. ina- knoek_ down * 17 Bezel. 111 Hornl, metal 18 Bindinl po.U 112 Hom., wooden 202 Setl, rec:eivina - Neut~ 19 BindinB po.t., In.ulat.-d 113 Hydromcterl dyne 20 Bool.. 114 Indicator., polarit, 203ISet., recei .. ing- portable 21 Boze., b.ttetY 115 Induet.ncea, C . W. .204 Seta. receivinc--r.dio rno- 22 Bose'.lroundinl 116 In.ulatic:m. molded TELOS 23 Bridle., wheat.tona tl7 In.ulation material 205 ~t~~CYrecei .. inc-refles 24 Broadca.tin, equipment 118 In.ulatore •• erial 206 Set., receivin.--recener.- 25 Bu.hin •• 119 In.ul.tore, eompo.ition. ti.. e 26 Buzzer. 120 In.ulatorl. fibre 207 Set •• rec:eivin s-Reinartz 208 Sell, receivi ne--seetion.1 27 145 Mice 232 Switch Itop. SO Conden.er., vari.ble arid 146 Mica .hcet. 233 Switche., aeri.l SI Conden.eu, ... ariable miQ 147 Milli.mmeter. 234 Switehcl. battery 52 Conden.er., vernier 148 Minera" 235 Switehel. filament 53 Contact pointe 149 Molded inlulation 236 Switchel•• round 54 Contaet •••w i. tch ISO Molybdenum 237 Switehe •• induebnce 'The Famous 'Trul, Portable 55 Cord tip. 151 MountinCI. coil 238 Swite he •• Pa nel 56 Corda. ror head ..... 152 Mountinll, CGndenler 239 Switehea, linlle .nd dou- 57 Couplen. loo.e le.k ble throw TELMACO P-1 Receiver 58 Coupler •• rnoldN 153 Mountin .... end 240 Tonejwhech 59 Couplera. vario 154 Mountinc •• Irid leak 241 Tower., aer'.l four Tubes Do the Work of Snen 60 Cryolal aliDY lS5 MountinCI, honeYcomb 242 Traneforme-r.. .udio fr.. The peer of portable8 In 8ize, weigbt. e8J!8 of toni!,a'. 61 Cry.tal hold... coil quency 62 Cry.t.t.. roulh selectint~. diae.u.ce. vDlume. workmaDob,p and ~nce. J56 Mountinc_, inductanco 243 Tr.neformer.,61.ment Aerial. load .l>C&ker and batteries •• If eolltalned. 63 Cry.ul •• mineral .witeh 244 T raneformer_, modulatioll 64 Cry_tal., .Yftthet'e Complete witb tabu and batteriee. $125 00 IS7 Name plate I 245 Tranlformer_, power 1143.60. Receive. onl~ • _ •• • 65 Cry.tA". unmounted J58 Neutrodyne .et p.rtl 246 Tr.neformere, pu.h-pull 66 Cry It.... , mounted 159 NUll 247 Traneformen. redio Ire- P·I IUt 5 ...... You Moaey I 67 De.kl, radio llSO Ohmeler. Oar otf~r of the Telm .. eo P- l ~ ei ver In kit fonn has I 68 OUe<:tor unit. 161 O.dll.tor. 248 !f-~:~!iorlnrrl ...ariable m e.... ·.1. " I.!.o..; __t o _ ~ ,;.,,' .u fi9 Detecton. cry.tal 162 Panel cuttin ••nd drillina 249 Tr.n.mittere partl. 88 b1l ilt b~ 118\ inc1adllll( c ...... drilled &nd en­ 70 Dete<:tor •• 6J:ed cry.tal 163 Panel... drilled .nd un_ 250 Tubea. V.CCUUm- pe. nut ~ved pan~l. Dud iI ...tr"tcd matructiOD8. 71 Dial. adjultere dril1~ 2S1 Tubea . .... euum-two al_ $80.00 72 Oi.", compo.ition 164 Panel •• fibre ment ~:~'::~~u o~ write ';s. Deserlptl';.. faldor free. 73 Die I •• hard rubber 165 Pane". h.rd. nJbber 2S2 Tuba., ....cuu"'-thre. el ... 7.4 Oiala. rheollat 166 P.rt. m!tnt <]{adio <[)iYiJion: 75 O i.h, metal 1U Pa_tlP, aolderin. 253 Tuner. 76 Dial ....ernier 168 P.tent attomey. 2s.t Variecouplere. h.rd rubb.r TelepboneMaiDtellallceCo. 77 Oiah with knob. 169 Phone CGnnccton. multl- 255 V .rioeou pieri. molded 78 Oiea pl. 256 V.riocoupler • • wooden so So. Well. St. Dept. C Cblcaso, III. 79 Ora... electrie 170 Phonovaph adapten 257 Variometera, nar d rubber 80 DrY cell. 171 PI.te., conden ..r 258 Variometer., r,olded 81 Earth ....."nd. 112 Plu". coil 259 Variometen. wooden ~ 82 Electrolyte 17l Plu.a. telephone 260 V.rni.h. (nlulatina 83 Enamell. battery 174 Pointore. di.1 and knob 261 Voltmetere 84 En.m*'., metal ITS Polee, aeri.1 262 Wa.hen as End .,op. 176 Poten t iolneten 263 WaYe Ineten 86 EYlPlet. 177 Punehin. machine. 264 W ...e trap. 87 uperimentaJ work 178 Reinart:z: .et part.a 265 Wire. eerial 88 Fibre .heet. nalc.anl%.d 179 Recenerat ive ..t parte 266 Wire. braided.nd.b.nd.d 89 Filter re.eton 180 Receiver cap. 261 Wire. eopper 90 Fi.ture. 181 Re<:ti6er., battery 268 Wire, in.ulatlfCl 91 Fuee cut out. 182 R ..i.t.nee le.lrl 269 Wire. Lit%. i2 Fueu, tube 183 Reli.tance unit. 270 Wire, m.gnet '3 Gener.tor •• hich fr"uencp 134 Rhea.tat b.lel 211 Wire, Platinum 94 Grid chOPper•• rot.ry 185 Rheo.t.t Itri p. 272 Wire, tung.ten

------RADIO AGE BUYERS' SERVICE. 500 N. Dearboru St.. Cbieago, III. ~ PIC:lllc ace that I am s upplied with buyi ng . pccificationa and prices OD tbe articles Dumbered berewith: • • I : • I am a - 0 Dealer 0 Jabber 0 MfllTo.' Rep. 0 Manufaeturu I • I • Firm [If identified with Radio industry] ______..___ ._ ..•. __ ..•___ _. __ . ____ . ___ .... ___ .• . ____ •

• My Oeellpatian - .-.------.. --.. ---.---.- ---- .. - .---.-.-- .- .-.... - ...• --.-.-.. -. I I My Name ._._ ._. ___ .. . _ .. _ ... __. ___.. _---.. - .... -.-. .. ----.------.-.. -.---.- ...... I I I The August number will be known as I Addren --.. - .•. - ..•-- . --... -----...• . -.. - ... - .--.--.-• .. - ..•• ------•.. --.-.-•...... - I " A ROUND-UP OF RADIO," and, ,.. ____- ______I P g • City _•. _._ . ___. ______._. . ___._ . . __ • Stat•. ____ ...•... __ ...•..... __ ... _ __ __. __ ._ • :~o:g e o~~e:pJ~:t~:::i~:i1l contain a

:{. Tested and Approt'ed by RADIO AGE :(. 72 RADIO AGE for July, 1925 The Magazine of the Hour Going Horatio Alger ,~""""""~~,~~""~"~~"""'~"""'~,~"""'" " , One Better (Continued from page 62) : With the Manufacturers : tion finally obtained in the tube labora­ : (Continued from page 69) : tories of the \\'estinghousc Lamp Com­ pany. This was before the public ever !------~ saw even the old UV200 and UV201 tubes - when 199's were but a dream, and fila­ Loop Set Preferable To Fall Radio Season Now On, ment currents of One to two amperes Antenna, Says Priess Is Claim were tolerated for receiving tubes. RADIO statistican recently con­ HE FALL radio season will com­ From this 11r. Silver graduated to a A ducted a research among radio mer­ T mence in June, as far as manufacturers large wholsesale house where his alert chants and learned that approximately of radio apparatus are concerned, declared mind quickly grasped the fundamentals 53 % of persons who enter stores to buy E. Alden, general sales manager for .the of what was at that time the radio busi­ radio receivers indicate a preference for Shaw Insulator Co., of Irvin~ton-Newark, ness of the booming early twenties. Then loop sets. N. J. Mr. Alde n based hIS conclusions another change, this time to a COncern William H. Priess, a well known engi­ on a trade survey which he recently which then consisted of but the chief and neer and president of the Priess Radio completed from coast to coast, during himself, but which soon grew to deserve Corporation, whose work for a number which he learned from manufacturers the title of "New York's formost radio of years has. been exclusively identified in every section that the demand for shop," where he served as aSSIstant to a with loop reception, is naturally one of radio apparatus by the buying public has prominent engineer, and contributed its strongest proponents. The percentage caused the manufacturers to advance toward the design of what proved to be of favor toward the loop which the statis­ their time for production on new equip­ the first popular super-heterodyne re­ tician's research showed did not surprise ment to the month of June. ceiver over offered for broadcast recep­ him. "Strange as it may seem," declared tion. Next, a trip to Paris, and medita­ "A loop set has a number of advant­ Mr. Alden, "the new date will have a tion coupled with the salt sea air fired ages," he said. "The set can be installed favorable reaction on the trade and his never latent ambition. quickly and moved to various locations will be the means of allowing the manu­ without entailing the services of a steeple­ facturers to more properly gauge the "A New Era" jack. It is the ideal set to take in the buying demand throughout the country. car on a day's outing or to the country At the present ti me it is apparent that -'HUS, in the early summer of 1924, there will be many new advancements Chicago saw the retail store of silver­ on a week-end. It can be installed in 1 places where the connection of "antennae made in set and parts construction dur­ Marshall, Inc., with the erstwhile vigi­ inlf the coming seaSOn. lante as its head. Events followed each is forbidden or impossible. "In addition to its inherent mobility, 'Notable among·these will be a greater other with a rapidity characteristic of the standard of development, together with radio industry, and by fall the young the loop receiver has the remarkable property of directional reception and refinements in general construction cal­ cOncern marketed a line of products culated to make radio equipment have a designed by Mr. Silver which met with freedom from certain types of 'static' disturbance. Two interfering signals greater appeal to the public, and, inci­ instant favor. The old story was re­ dentally, be the means of giving radio' peated-production could not catch up of approximately the same strength and wavelength but coming from differ... its rightful place in the ranks of the with demand, and winter saw Silver and world's greatest medium for good enter­ his partner wor king shoulder to shoulder ent directions cannot be separated by the ordinary ante nna set. With the tainment and instruction. with the ever increasing force of the new "The entry of many new and substan­ growing concern. By spring the partners loop receiver, however, this separation can be made complete by turning the tial COnCerns into radio fields during the saw the re wards of their labors in the coming seasOn will be one of the greatest ever-extending businessthey had built up. loop so that one of the stations disappears, and tuning in sharply on the other means of stabilizing the industry. From Mr. Silver is probably best known to present indications there will be a variety the radio public as the designer of many station. "With the right set and the right loop, of manufacturers sound financially, and pieces of radio equipment and a number with progressive ideas in manufacturing of receiving circuits of exceptional merit, satisfaction over the antenna set is certain." in mind, which will have a stimulating several of which have been described in tOne for the entire industry and be the this publication. In addition to his com­ means of placing it on a more substantial bination of business and en~ineering Gain in Squeals Very Small, basis than ever before in its history. ability, his capacity for describing radio Says Expert apparatus involving complex circuits in "Parts will be again popular factors a manner so simple that the average lay­ HE GAIN in radio reception by mak­ during the coming season," declared Mr. man can easily comprehend, is one seldom T ing the single circuit receiving set oscil­ Alden. "One of the leading dealers in met with. His articles have appeared in late and thus set up a discordant howl in this country with whom I talked during practically every important radio publi. all the other receiving sets in the neigh­ my recent trip declared that the parts cation anrl newspaper in this country. .. .' bothood, is so very small that it does not end of his business has been holdin,g up as Desiring to see the genus homo in his begin to comi>ensate for the added an­ good during the early Spri ng season as it lair, we called upon Mr. Silver one day. noyance, L. \Y. Chubb, Manager of the did during the past Winter. The trend \Ve were ushered into the presence of a radio engineer staff, \Vestinghouse Elec­ tric & Manufacturing Company, points during the coming seasOn will be in the mere stripling seated at an unimposing direction of better merchandise, appeal­ desk, who, when he arose, proved to be out. over six feet. In the course of our getting The gain in reception through setting ing prices, and merchandise, which is several words in edgewise, telegrams flew up' oscillation, when receiving from a one calculated to bring radio to higher levels out, apparently important matters were kIlowatt station, actually is a small frac­ in the public's buying and mind, and settled, and ideas evolved and rushed to tion of One per cent. The electrical engi­ consistent with the great appeal that the laboratory for immediate experiment. neers have determined an infinitesimal radio has heretofore generally enjoyed." From a shelf he selected one of a ~ain in comparison with the loss caused number of receivers, handed it to an In the sets of peoples within a radius a ssistant, and in an instant a volume of of two or three miles who are listening deny them the pleasure of their present sound poured out of the loud speaker that in on t he station. . freq uent visits with relatives and friends was amazing, yet with perfect quality. The remedy for the interference caused in distant locations, would slow down "What is it?" we asked. After a by single circuit radio sets is not in pro­ business and in numerous ways would moment the answer came, briefly: "J ust hibi ting the sale of these sets, as advocat­ be a drawback. The ideal remedy for a six-tube super-heterodyne. I call it ed in some quarters, but in _proper use the losses caused by use of the automobile the 'Super-Autodyne,' because it uses an of the set!;, according to ;\1r. Chubb. lies in bringing the individual to so drive autodyne frequency changer." "The situat ion is somewhat analogous his machine that the losses will be elimi­ "Autorlyne frequency changers" not to use of the automobile," Mr. Chuhb nated and the gains conserved. being in our voc.abulary, we left after a says. "On occasion the automobile has "So it is with the single circuit radio few minutes conversation, impressed destroyed lives of passengers and pedes­ receiving set. This type of set repre­ primarily with the sudden transition of trians, or otherwise caused great suffering sents the most for the money that the the man from the capacity of executive and distress. To stop this, we might individual Can buy. This simple device to engineer and back again, and the outlaw the use of the automobile, but using One or two small tubes and inexpen­ sincerity, certainty and energy that this would deprive millions of people of sive dry cell batteries, gets strong signals seemed to pour forth with every word he the enjoyment of a perfectly legitimate from the broadcasting station and is uttered, either as president or engi neer. pastime, that of automobile riding; would capable of getting great distances." rn ='G' il:Jl 'I:J~I:J' 'l:Ji 'tzJ' 'til' ,[;]1 iG' 'GI 'G' il:Ji II:J~I:J' ~ Is The ~ ~ H ANNUAL" ~ ~ on your ~

~ Summer ml ~ List? rn

8 IF YOU intend to take a trip ~ this Sum.mer, you're surely mi' m going to keep in touch with W I:J~ Radio, either by bringing a set I:J along or building one during the ~ duil afternoons, from parts you ~ can take with you. mi' MTO how are you going to build ~I:JI' ru this set or study upon radio for the big season that A Big Blueprint Section is bound to come in September? I:JI' The answer is simple. All you have to do is to invest for your Dollar! ~I!II' ONE DOLLAR in a RADIO AGE ANNUAL for 1925, the How many blueprints couid you buy for a ~ world's most complete and authoritative hookup book, dollar if you started out to buy them, one I:JI' and take it with you, whether you go to Eagle River or the by one1 Very few, you'll admit. Yet in the ~I:JI River of Doubt. RADIO AGE ANNUAL for 1925 you'll find sixteen full pages of blueprints in actual ~I:J Let the ANNUAL for 1925 be your Radio Companion this color, explaining concisely every important . Summer! It will tell you whatever you want to know in simple and complicated hookup developed I:J 'I the radio line-from troubleshooting of the little faults during the past year! The 32-page blueprint ~ that may develop far from home-to the actual construction section of the ANNUAL is worth many ~til of simple portable sets or elaborate multi-tubers. times the purchase price of the book alone. . Order the ANNUAL NOW-for the lilnited I:J "'. GET THE ANNUAL NOW- and THEN go on your vacation! first edition is rapidly being nought up by ~ ...~ It will be your radio safeguard! eager radio enthusiasts. W ~ ~l~O~; RADIOF~~E191fNUAL r~o~; ~

How '0 ,ud .nd ondu",nd hookup.. Some of the ,ciu hookup>. Bob, H« No. I. . ~ How to understand radio phenomena. "~:~:~~=:d'O<'.Wonder Super-Het. and others . I:J~ Building your flrst sitnple set:. How to get rid of interference. ~ How to select the right receiver. How to make an amplifying unit. S ubstituting a tube for a crystal- building thO! first tu~ Set. How to recognize and deal with every kind of tube trouble. ~ How to amplify any kind of set. Another super-heterodyne for the super experimenters. Gl Making a reflex set. Hints on tracing troubles in super-heterodyne circuits. Building your flrst Reinartz set. I:J The renowned Baby Heterodyne No. 1. A three-tube long distance regenerator. ~ Adding audio and radio stages to the Baby Het. A 3-tube set that easily receives KGO on the loud speaker How to make a battery charger. from Ohio. ~ How to make a lOUd speaker. Improving the ever popular Reinart:. ~ ~~~:ho~~::!~~~~~:: ~~ ~~~~:~~~:~~ ~-~~H~'~' :~~p~ A:D __~

RADIO AGE. INC.. 500 North Dearborn St.. Chicago, III. ~I:JI' ~I Gentlemen : I want to be one of the first to get the RADIO AGE AN"JUAL FOR 1925. E nclosed find $1.00 If ~ ~::::~~~i:~~=i'~'~.'. ~~~~~.~.~ . =ill . '.':~'~ .". ="~i:~v',,::::~=. ~'."'.'(~~~=~""Iln':_ _..._. .. _...... _ mi' ~ ~~:~:~.~:~.~::.'::.'.':::.'.':::~.'.':::~'~'.'~'.'.':~'::.'~.':.~'~::~.'.'.~'~:.'.'.'::.'.':.'.~.'::.'.'~ , '.'.':.'.~'.'~~.~':.~'::.~~'.'.'.'.~'.'.'.'.':.'.'. ~'.'.~~·.·.·~·.~·.·.·.~·S~:~~·.·:~~~~~~~~~~~~=::::::~=::::::::::~:::::::::: :~::~~:::=:=:::== W

~~,5 1til' 'til' 'I:J' 'til' !~I . . '[;II 'till 'til~I:JI Ie! I!::II 'til' IsJ ",LONlo DISTANCE ... TRADE MARK REG. RAD I 0 While MacMillan Charts the Arctic Zenith Broadcasts to the World!

Between Alaska and the North Pole stretches great a risk, both in capital and human life, only an unexplored area one million square miles in the best in radio equipment can possibly com­ extent-the last remaining "blind spot" on the face mand a place. Once more, therefore, MacMillan of the globe. chooses ZENITH exclusively, both for his ships Over this vast area will fly, this summer, two and for the two great planes flying across un~ great planes of the amphibian type, piloted by U.S. charted seas of ice. Navy air pilots and equipped with the most highly Thus, while the world awaits reports from this perfected scientific apparatus obtainable by the greatest expedition of modern times, it is worth United States Government. This entire expe~ remembering that the only way these reports can dition, which has rightly been described as the possibly be transmitted is by Zenith radio. greatest expedition of modem times, is under the Never in all your life, it is safe to say, will you direction of Commander Donald B. require ofa radio set such outstand­ MacMillan. ing performance as MacMillan re~ The purpose of the expedition is quires of ZENITH in the Arctic. the study and photographic chart­ But can you imagine greater satisfac~ ing of this unknown area-and­ tion than to know that your receiving new t ests in radio transmission and set can deliver such performance, reception of unparalleled importance. any time it's called upon to do so? The section to be explored has never Call this evening at your nearest been heard from by radio. Commu­ ZENITH dealer, and ask him for 9 nication will of necessity be day­ demonstration. light communication, for in this Super­ area the days are six months long. Zenith IX Zenith Radio Corporation On an expedition representing so 310 S. Michigan Ave., Chicago, In. Costs More- But Does More

HE complete Zenith line ranges SUPER-ZENITH VII-S,x tubes - 2 stages tuned reproduce both high and low pitch tones otherwise in price from $100 to $475. frequency amplification-detector and 3 stages a udio impossible with singlc-unit speakers. $475 T frequencY amplification. Installed in a beautifully Price (exclusive of tubes and batteries) With either Zenith 3R or Zenith finished cabinet of solid mahOIl~nY - 44U inches long. All PrI;,cs F . o. B . FactorY 4R, satisfactory reception over dis­ 16 ~i Inches wide, 10 ~ . inches high. Compa rtments a t tances of 2,000 to 3,000 miles is either end for dry batteries. Price $240 ,------readily accomplished, using any (exclusive of tubes and batteries) ... _ .. _ ... ordinary loud speaker. Models I Zenith Radio Corporation 3R and 4R licensed under Arm­ Dept. C-7 strong U. S. Patent No. 1,113,149. I 310 S. Michigan Avenue, Chicago, llIinois They are NON-RADIATJNG. I Gentlemen: Please send me ilJustrated literature about Zenith 4R .. $100 SUPER-ZENITH IX-Console model with addi_ I Zenith Radio. Zenith 3R .. $1 75 tional compartments containing built-in Zenith loud speaker a nd generous storage battery sPacc. The new Super-Zenith is a six-tube I Name ...... set with a new, unique, and really ~~~~. ..( . ~.~ .~~~ .~ ~ ~~ .. ~ ~ . ~~ .~~ ~. ..~ .~.~.. ~ ~~~.~.~~ ... $355 different patented circuit, con­ I Address ...... trolled exclusively by the Zenith SUPER-ZENITH X-i:ontains built.in. patented, Radio Corporation. It is NOT Super· Zenith Duo-Loud SPeakers (harmonically regenerative synchronized twin sPea kers and horns), designed to I ......

¥- Tested and Approt'ed by RADIO AGE ¥- This file including all text and images are from scans of a private personal collection and have been scanned for archival and research purposes. This file may be freely distributed, but not sold on ebay or on any commercial sites, catalogs, booths or kiosks , either as reprints or by electronic methods. This file may be downloaded without charge from the Radio Researchers Group website at http://www.otrr.org/

Please help in the preservation of old time radio by supporting legitimate organizations who strive to preserve and restore the programs and related information.