Blueprint Section Every Month

How to Make A Tube-Tester A Power_ Supply Receiver An Improved Reinartz A Six -Tube Portable Set Other Up -to -the- Minute Articles

MA ENT FAVORIT 55__ They Cost More But They Do More

The complete Zenith line ranges in price from $100 to $475.

Zenith With either Zenith 3R or Zenith 4R, sat- isfactory reception over distances of the exclusive choice 2,000 to 3,000 miles is readily accom- plished, using any ordinary loud of MacMillan for his speaker. Models 3R and 4R licensed un- North Polar der Armstrong U. S. Pat. No. 1,113,149. Expedition They are NON -RADIATING. Zenith 4R - - $100 Zenith 3R - - $175

Super - Zenith X- The new Super -Zenith is a six -tube set the ideal radio set with a new, unique, and really different for the fine home patented circuit, controlled exclusively by the Zenith Radio Corporation. It is NOT regenerative. SUPER -ZENITH VII - Six tubes -2 stages tuned frequency amplification - detector and 3 stages audio frequency amplification. Installed in a beautifully Zenith Supremacy finished cabinet of solid mahogany - 44rs inches long, 16ii inches wide, 10': inches high. Compartments at either end for dry batteries. Price (ex- will be Maintained elusive of tubes and batteries) $24O SUPER -ZENITH VIII- Same as VII ex- This message brings to radio en- for the makers of that product a cept- console type. Price (ex- elusive of tubes and batteries) $260 thusiasts the announcement of an standard of supremacy which, in advance in Zenith prices on all duty to the public, they are obligated SUPER -ZENITH IX - Console model The new prices are shown to maintain. with additional compartments contain - models. ingbuilt-in Zenith loud speaker and gen- in the panel at the right. Throughout the radio world the erous storage battery space. Price (ex- clusive of tubes and bat- Radio sets -like motor cars and name ZENITH has come to be the teries) pianos -gravitate to their correct very symbol of results -in quality of price level. There is more to a radio tone, in simplicity, in selectivity, in SUPER -ZENITH X- Contains built -in, patented,Super -Zenith Duo-Loud Speak- receiving set than merely a beauti- volume without distortion, and in ers (harmonically synchronized twin ful cabinet backed by extravagant long -distance reception. The artistry speakers and horns), designed to repro- meet exacting re- of design for it is too duce both high and low pitch tones claims. It must which stands otherwise impossible with single -unit quirements. The novelty has worn well known for comment. speakers. Price (exclusive of 71 off. The public is becoming edu- The fact that ZENITH has ad- tubes and batteries) $4 ( 5 cated. It knows what to expect and vanced its prices is of more than Prices F.O. B. Factory. can now distinguish merit in radio. passing moment. For it registers the All An imposing name and an intensive determination on the part of the advertising campaign -when they builders of ZENITH to maintain back a radio product which does not the acknowledged supremacy of deliver equally impressive results - ZENITH receiving sets -both in soon lose their fictitious values. beauty and performance. ZENITH RADIO CORPORATION Dept. C-5 By that same token, performance All present models are guaranteed 332 S. Michigan Ave., Chicago, Ill. which is literally outstanding fixes against price reduction. Gentlemen: Please send me illustrated liter- ature about Zenith radio.

Dealers and Jobbers: Write or wire for our exclusive territorial franchise. Name Zenith Radio Corporation Address 332 S. Michigan Ave. Chicago, Ill. J

2 Tested and Approved by RADIO AGE ' RADIO AGE for May, 1925 The Magazine of the Hour 1 O Else Wants $5 t PROOF!

$405 In One Month I cleared up $405 in one month recently. Do short hours, big money and easy Not so bad-is it -for a fellow who just com- pleted your course a work appeal to you? short time ago. I sure have been coining the dough, I never will IGHT now thousands of men are best obtainable at any price. The whole regret the money I "cleaning up" in Radio. Right on success of the Institute is based on its paid for your course. this page you can read the signed state- advanced methods. This is the ab- Emmet Welch, Peculiar, Mo. ments of men who have made big money solutely complete course now being in this "wonder- field." Men, who, a few offered which will qualify you for a govern- months ago, knew nothing about electricity ment first -class commercial license and From $15 to $80 a Week or Radio now hold fine positions and earn really get you one of the bigger paying Before I enrolled more money in one week than they used jobs in Radio. with you I was mak- to get in a month! ing $15 a week on a farm. Now. I earn Every day thousands of Radio sets Free Instruments from $2,080 to $4.420 are being sold; broadcasting stations are a year and the work The Institute furnishes free of charge all is a hundred times being established; Radio stores are spring- instruments necessary for practical in- easier than before. ing up everywhere. People all around Since graduating a struction at home -you "learn by doing." little over a year ago. you are getting rich in this splendid - That is one reason why National Radio I have earned almost paying profession -Why Not You? $4.000 and I believe the course will be Institute graduates get ahead so quickly, worth at least $100,000 to me. You can train for this "big-money" and obtain the Government License easily. (Signed) George A. Adams. field in your own home -in a little spare Tamaqua, Pa. time. No electrical experience is neces- Send for "Rich Rewards sary. Men and boys of all ages-14 to 60, Triples Salary have mastered this famous course in a few in Radio" and Special months. What others have done, you can Short -Time Offer I am earning three do. times as much as be- book will tell you the fore enrolling and I Radio has come to stay. It is the fastest This interesting have clean interesting growing industry in the world today. But full story about the wonderful opportuni- work that takes me to in Radio. You will see for yourself all parts of the globe. remember -the "cream" will go to the ties I tell you, boys, it's just how much you can expect to earn in Radio for me. shrewd fellows who get in on the "ground Arthur Berke, floor." Employers are constantly writing this great profession. It will tell you of the Vancouver. B. C. to the National Radio Institute asking for adventure and big money that awaits the Radio Operators, Salesmen, Radio Engi- ambitious man in this fascinating field. at once will be Earns College Education neers, Radio Mechanics, Broadcasters, etc. Those who mail the coupon Many of our students, even before com- offered a special reduced I entered the mari- pleting their course have received offers of rate, Act promptly and time service of the save money! Send Radio Corporation of fine positions at twice their former salary. to- and served day for this free book America In fact, most students make so much Rl several months on and our special short P +ca;s board ship. I not money in their spare time on Radio work .n only had the advan- Becomes Practically Free. time offer. no, tages of visiting foreign that this Course countries at no cost to me, but I was also Secret of this NATIONAL RADIO able to save enough What Is the money to pay for my tuition to college. INSTITUTE G. E. Rogers, Amazing Method? Troy. N. \ The National Radio Institute Course is Dept. 53GB l acknowledged by Radio executives to be the Washington, D. C.

! National Radio Institute, Dept. 53 GB, FREE Instruments Washington, D. C. I Send me the book, "Rich Rewards in Radio," whica I tells all about the opportunities in Radio, how spare time impractical trainingathome I study at home will qualify me quickly as a Certified - I Radio- trician so I can get one of these splendid positions. I and how your free Employment Service helps me to I secure a good position. Also, details of your Special I Short Time offer.

Name-. - ...... ___ These parts with instruc- This is the world- famous Natrom- t mis are given for experi- These parts with com- eter of the three instruments -one ence and practical training plete instructions are Address"_._.._.... »_ ___...... _.._.._._ given for scientific and practices in making and operating given for practice in home training in mastering the regenerative receiving ap- building a receiving code. paratus. set of the more simple kind.

-F Tested and Approved by RADIO AGE © C1B657753 3 RADIO AGE for May, 1925 The Magazine of the Hour A Chat With a IC) OZ the Editor The Magazine of the Hour Corporation of America, Established March, 1922 it appears, is not at all in a WITH WHICH IS COMBINED RADIO TOPICS RADIOhurry to submit proof that this magazine is not entitled to the use of the name which we have been using Volume 4 _flay, 1925 Number 5 for more than three years. Radio Cor- poration, with great show of moral in- dignation, went into the United CONTENTS States Patent Office at Washington Cover Design by Fred I. Good last Fall and made formal protest against the registration of the title Radio Editorials 4 "Radio Age," which name we had Where the Howls Come from 7 sought to have officially enrolled as By Frank D. Pearne our trade mark. Radio Corporation A "Quiet" Regenerator 9 claimed that the use of the name By Arthur B. McCullah "Radio Age" was causing damage to tireless Age, the organ of the How to Make a Vacuum Tube Tester 11 Corporation, owned and controlled By H. Frank Hopkins by the Corporation. 13 A Power Supply Receiver Radio Corporation was to have sub - By Brainard Foote mitted proof to substantiate its ob- All Ready for a Radio House-Cleaning? 15 jections to the use of our name. The By Paul Green Patent Office said this proof must be An Improved Reinartz Receiver 17 submitted on or before March 21. By Ray G. Piety Instead of offering proof, Radio Cor- asked for a continuance. A Receiver 19 poration Unique Super -Heterodyne Our counsel consented once more. By Joseph Caece The case will not come up until late The Physical Significance of Tuning 22 in April, when there likely will be By Dr. Frederick W. Grover another request for delay. "What the Broadcasters are Doing ": RADIO AGE Meanwhile RADIO AGE moves on Studio -Land Feature Section 23 smoothly. It broke all its own records RADIO AGE BLUEPRINT SECTION 31 for circulation and advertising in the A Six -Tube Portable Receiver March, 1925, issue. We continue to receive letters from wish - By John B. Rathbun many fans ing us success in our defense against RADIO AGE Institute Monthly Tests__ 39 the 533,000,000 band of Broadway The World's Smallest Studio on the Air 40 radio patriots. Pickups and Hookups by Our Readers....______.__ 41 Radio Corporation is fortunate in obtaining delays. The Corporation was to have appeared before the Federal Trade Commission on March Radio Age is published monthly by RADIO AGE, Inc. 18 to answer the charge that it is Member: Audit Bureau of Circulations. involved in a trust conspiracy. Radio Corporation wanted delay. Although Address all communications to RADIO AGE, INC. were filed a ago, Executive, Editorial and Advertising Offices the charges year 500 N. Dearborn Street, Chicago, Ill Radio Corporation obtained more Publication Office, Mount Morris, I11. time to present its defense. Changes have been made recently FREDERICK A. SMITA, Editor in personnel the Federal Trade RrSSELL H. HOPKINS, Associate Editor the of FRANK D. PEARNE, Technical Editor Commission. \\ a venture to suggest M. B. SMITH, Business Manager the hope that the Commission still will be courageous, fair, persistent, Advertising Director and diligent in pushing this radio HARRY A. ACKERBURG trust inquiry. Why should it not? Eastern Representative If there is a radio monopoly-bust DAVIDSON & HEVEY, 17 West 42nd St., New York City it now!

Final Advertising forms close on the 20th of the 2nd month preceding date of issue Issued monthly. Subscription price $2.50 a year. J. _ _ _ t Entered as second -class matter at post office at Mount Morris. Illinois, under the Act of March 3, 1879. (, Coswi.At.IWS, by RADIOAGE.I.. Editor of RADIO AGE RADIO AGE for 1\1ay, 1925 The Magazine of the Hour 3 ¡Recommend EVEREADY HOUR EVERY TUESDAY AT 9 P. M. (Eastern Standard Time) For real radio enjoyment tune in the "Ever - batteries eady Group." Broadcast through stations - good WEAF New York WFI Philadelphia WJAR Providence WCAE Pittsburgh WEEI Boston WGR Buffalo IN AN effort to reduce the first cost of a WEAR Cleveland WOC Davenport buys WWJ Detroit =Minneapolis radio set, a newcomer in radio often WCCO f Paul St. inferior batteries. You know such "sav- ing" is really wasteful. Tell your friends who are about to buy receivers that the best batteries obtainable will prove to be the most economical. Tell them to buy Eveready Radio Batteries -they last longer and, because they are greatly supe- rior, they give complete satisfaction. There is an Eveready Radio Battery for every radio use. Manufactured and guaranteed by NATIONAL CARBON COMPANY, INC. New York San Francisco Canadian National Carbon Co., Limited, Toronto, Ontario EVEREADY Radio Batteries they last longer

Eveready Columbia Ignitor Dry Cell "A" No. 770 45 volt Battiry Extra ¡or all Large Dry Cell Vertical Tubes Price l\ I% volts $4.75 i For up- on multi tube srts

No. 767 45 -voll Large Horizontal Price $3.75 With variable taps

sF Tested and Approved by RADIO AGE 4 RADIO AGE for May, 1925 The Magazine of the Hour 10EDITO

EBER MacDONALD, writer of pub- Paul they seems to speak as one man: "This one licity for the Grebe radio people down thing I do, forgetting those things which are behind H at Richmond Hill, N. Y., has written and reaching forward unto those things which are a classic commentary on the radio trust. It is before; I press toward the mark." This valiant little so good we are printing it in full. Know ye all group of independents have a fixed image in mind men that we agree with every statement in the from which all this extraneous and non -essential patent editorial. RADIO AGE has had some direct hokum has been extracted or subtracted. experience with the Radio Corporation of America Meanwhile, in the ranks of the Four Horsemen and the radio public now knows pretty definitely there is much gnashing of teeth. This great radio what we think of the patriots who have just Goliath of Greed may have its day of recknoning been favored with another delay in their hearing put off again and again -as instanced by the recent before the Federal Trade Commission on the delay on March 18 -but the end is not afar off. The charge of being involved in a conspiracy to Trust- buster is just around the corner. Some one gobble up the radio industry. - had better summon a Daniel, for there surely is a Mr. MacDonald's editorial follows: hand -writing on the wall: "MENE, MENE, TEKEL, UPHARSIN." The free translation seems to be RADIO fans -come out of the past -it's haunted. "Thy kingdom is numbered. Thou art weighed in At least it looks that way, especially since history the balances and found wanting. Thy kingdom is repeats itself. You may have noticed the Selden divided and given to the Medea and Persians." patent crowd passed into the cold and unrelenting Uncle Trusty, they have your number The bearers grasp of a receiver the other day. If you have any are at the door. recollection of the early days of the automobile busi- ness, you must recall Selden and his patent. It was THE use of radio broadcasting stations as advertis- a wonderful patent. It worked day and night. No ing machines is the greatest peril the new art is time off for good behavior. No one could make any facing today. The eager listener who hopes to hear money with it and Selden said no one would be allowed good music and who instead gets a dissertation on Jones' to make any money without it. And in those olden, pills or Brown's sausage is not going to remain a golden days, Selden was all -powerful. He even ad- devotee of the dials. In promoting advertising as a mitted it on high days and holidays. means of financing stations, the broadcasters who have About the country like a roaring lion went Selden succumbed to the commercial influence are building seeking whom he might devour. Courage sprang up a monster who, like Frankenstein, will slay its from his clenched fist. He shook his patent at every creator. auto -maker and collected much largess. They were Chicago has three advertising broadcasting stations taxed to live. And this tax was a heavy drain on the and is about to acquire more. New York has a big then infant motor-car industry. But once on a day advertising station in WEAF, and the saddest part of a young manufacturer in Detroit, H. Ford, by name, that story is that the ballyhoo was organized by the told the Selden gang where they could go and he American Telephone and Telegraph Company. The strongly advised them to take their leech -like patent Pacific coast has its advertising problem. "Radio," with them. the San Francisco monthly, says in its April issue: Such a patent octopus is considerably like an over- along comes some one armed with the "Radio is too fine a thing, it has too great possibili- inflated balloon; in the advancement of human welfare, spear of common sense and the balloon is bust. 'Most ties to be a good chance prostituted to such base ends. If this practice continues any man with back -bone has to deflate if the warnings An octopus is always an evil. Thrice to increase, and, are not heeded, the an octopus. will realize that it is being imposed is cause is just. The octopus trembles public upon and armed he whose forms of entertainment." at the very mention of justice. turn to other And what has all this dissertation to do with radio? The writer was discussing the advertising peril with Nothing much except that there is another patent a conspicuous leader of radio activity and thought octopus trying to suck the life -blood out of the inde- recently, and suggested the desirability of vigorous pendent radio manufacturers who have not bowed the agitation against such misuse of the air. The radio knee to Baal. The independent radio manufacturers man said there was no question about the danger of believe they have the right to live without paying advertising propaganda to the radio industry and the tribute to the radio trust. This right to live is denied radio art IF SUCH ADVERTISING WAS CON- to the independent radio, manufacturers by the minions TINUED. But, he said, the disease would cure itself. of the fat and over -fed radio trust. A brilliant array He confidently expressed the opinion that the public of expensive legal talent do the daily bidding of the would solve this problem, as it has solved other radio Four Horsemen of Destruction. problems. The public would calmly tune out the ad- But the little band of independents know not fear. vertisers until the "broadcaster - for - business - only" They have forgotten the Trust and its threats. The found that he had no audience and then he would have Trust belongs to the stolid past. The Independents to quit for want of contracts. A consummation de- look to the plastic future. In the words of the Apostle voutly to be wished, and may it come speedily. RADIO AGE for May, 1925 The 1114gazine of the Hour 5 Radio at Finest is Now Within Your Reach

N /41/ SIN * AN ALL -AMAX RECEIVER At your favorite Semi - Finished - Factory - Mounted Radio Store buy this set with the ALL -AMERICAN parts prop- YOUerly mounted on the panel and baseboard. Without Ask them about knowledge of blueprints, circuits or names of radio parts, the great you can wire up an ALL -AMAX SENIOR In one delightful eve- ning and know that it is right. It was inevitable that sooner ALL -AMERICAN or later this reliable -and still economical- method of getting Slogan Contest a high -grade radio set should be discovered. ALL -AMERICAN You can win manufacturing ingenuity has found 1;.'sr..6°®®®tiva,- the solution and offers this com- a set by pletely mounted, highly efficient submitting a three -tube set at no more than you would pay fora kit of parts. Price, $42 SLOGAN v Ten cents will bring you the new Radio Key Book, and upon request we will include, free, Everybody can a complete wiring blueprint of either ALL - ALL -AMAXJUNIOR enter. It costs AMAX SENIOR or ALL -AMAX JUNIOR. The same unique manufacturing E methods that created ALL -AMAX o SENIORhavebrought f' nothing ALL -AMERICAN forth ALL - RADIO CORP. o AMAX JUNIOR -a one -tube set E. N. Rauland, President that brings in the local stations 2680 Coyne Street, Chicago on the loud speaker,ortunes them out and gets real distance. All parts are mounted on panel and baseboard, and clear photo- 6 ®® graphic wiring directions $ 74 are included. Price . _ 22 A

J Tested and Approved by RADIO AGE kt 6 RADIO AGE for May, 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 Magazines. 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. -7'25 Moir RADIO AGE for May, 1925 The Magazine of the Hour 7 i Dr l r 11DO 1 1 I D or ID1 I t ,13=-1

.71°ae Maga3ine 1: the Hour

A Monthly Publication M. B. Smith Devoted to Practical Frederick A. Smith Business Manaar. Radio Editor

I o D1 DI IDI 1 I IDI IDL Self-Oscillations in R.F. Circuits Where The I IOWLS Come from IT IS a well known fact that in order until it reaches a point where it becomes to get good long distance reception, By FRANK D. PEARNE stabilized and no further increase takes radio frequency amplification must place. Aside from building up the signal be used. This type of amplification on the grid, it has the effect of prolonging strengthens the incoming signal, amplify- Control of Feedback the signal to a certain extent, the result ing it to such a value that it becomes being a considerable amplification of strong enough to make enough impression is Vital the signal by this regenerative method. on the detector to make audible those for Clarity This is known as a feedback, and signals which otherwise could not be because it may be controlled, it becomes with the ordinary receiving sets. a useful and valuable adjunct to the heard known a feedback, in which part of No are included in the different as receiver. Thus we have a case where jacks amplified energy is fed back from stages of radio amplification for the the controllable oscillation is a benefit, circuit to grid of reason pass through all of the plate the the tube. but those self oscillations which are set that they In this case, either a tuned plate circuit these stages at a frequency which is up in many sources of feedback which or an inductive coupling of the plate too high to be heard by the human are not under control are the cause of much is used. Here we have a not made audible until and grid circuit the many howls squeals so ear. They are impressed upon the grid and often through the detector, where signal and encountered in radio frequency amplifi- they pass amplified by the relay action of the tube they are brought down to audible fre- cation. Where several stages of radio Therefore, are of no in the plate circuit. When a change frequency amplification used, some quency. jacks in of are preceding takes place this plate circuit, part of the energy of the consequence at any point impressed upon grid plate circuit may detector. After reaching this point, the energy is re- the be fed back to the grid circuit to the by induction, which again affects the however, the signals may be passed circuit same tube, or to preceding tubes by grid, making a still greater change through various stages of audio fre- the induction or capacity in the circuits quency amplification for the purpose of in the current flowing in the plate circuit. themselves. of the rectified This change or increase reacts upon the increasing the volume grid still changes signal, and jacks may be inserted between again, making more Coupling Causes Trouble stages, making it possible in the plate circuit, which effect keeps FEEDBACKS of this kind are un- any of these the to vary the volume as desired. Most building up charge upon the grid desirable, and unless some method all long distance receivers operate on of controlling them is used, self oscilla- the basis of both radio and audio fre- tion of the tubes will cause an aggra- quency amplification, and no matter vating howl in the phones or loud what type of radio frequency amplifica- speaker. Now this action is caused by tion is used, there will always be a great an unintended coupling somewhere be- tendency towards self oscillations in tween the grid and plate circuits of these circuits. the tubes. Perhaps in the wiring of the set the wire connected to the plate of Cause of Howls and Squeals one tube may be too close to the wire WHEN self oscillation occurs, howls connected to the grid of that, or some and squeals of all kinds are pro- other tube, or perhaps these two wires duced in the phones and if these oscilla- may parallel each other for some dis- tions cannot be controlled, the benefits tance, in which case one will be affected derived from radio frequency amplifica- by the other and self oscillations win tion are of no value whatever, and the be set up. set might better be used ,without it. This, however, will not always occur, Fortunately, however, there are several for the reason that if the feedback ways of eliminating the self oscillations, occurs in one direction, it may tend and if this is properly done, the receiver to oppose or neutralize the grid effect, may be made extremely sensitive and Fig. 1. Here current is induced in the having a tendency to dampen out the practically noiseless so far as these secondary by a primary circuit. This grid effect instead of building it up. oscillations are concerned. In order secondary current acts upon the grid, which Where many stages of radio frequency that one may fully understand just varies the current in the plate circuit. are used, coupling between This varying current passes through the amplification what causes this trouble, it will be tickler coil which again causes an induced the plate and grid circuits may occur necessary to explain briefly the principle current in secondary, thereby affecting the in many ways. There will always be a of regeneration. The well known grid once more, making a greater change in capacity coupling between the plate regenerative set makes use of ghat is the plate circuit. and grid of any tube, because these two 8 RADIO AGE for May. 1925 The Magazine of the Hour

end of the tube filaments. If it is found that the tubes oscillate when the poten- tiometer is set at the negative side, the oscillations may be dampened by moving the arm towards the positive end. Making the grids of the tubes positive with respect to the filaments will natur- ally reduce the impedances of the grid filament circuits, and if this is carried too far, the grid filament circuit begins to be conductive, and some of the plate current will be wasted; but if the grid circuit is carefully balanced against the feed -back, then the self oscillations of the tubes may be easily controlled. The one bad feature of the potentiometer method is the fact that controlling the oscillations in this manner is absolute, but it increases the resistance of the circuits and naturally the amplification is reduced. It will be noted for example, in the use of a superheterodyne circuit, certain Fig. 2. Controlling the feedback from one stage to another by means of a special that at adjustments of the 3 -plate condenser. potentiometer the set will oscillate in a disagreeable manner, but the volume elements act just as though they were former amplification, providing the secon- of the signal is wonderful. However, the plates of a condenser. This capacity dary connections of the transformers in order to clear up the reception and coupling is always present and cannot are reversed in relation to the primary make it quiet, the position of the arm be avoided, and the only way to over- connections and a small variable con- on the potentiometer must be changed, come it is by neutralizing its effect in a denser connected . between the plate and as the oscillations begin to dis- manner similar to that of the neutrodyne circuits of two tubes. appear, the volume drops off to a con- circuit in which neutralizing condensers siderable extent due to the increased are used. The Potentiometer Method resistance. If some method could be The coupling may be caused by ANOTHER arrangement, and the devised by which the oscillations could magnetic action between transformers one which seems to be most popular be damped out and the volume still which are too close together, and again among the manufacturers of radio fre- retained, then great amplification might it may be caused by resistance coupling quency sets, is the potentiometer method. be had, with the use of less tubes than where the internal resistance of the In most cases the grid return circuits are now necessary. More stages of plate batteries is high. Now the energy of all the tubes are connected to the radio frequency amplification are re- which is fed back in any of these cases negative side of the filament battery. quired, of course, to make up for the may be either positive or negative, and This tends to prevent oscillations taking loss occasioned by getting rid of the self if it happens to be positive in its direc- place in the tubes, but is not adjustable. oscillations in the tubes. There is a tion, or if a positive feedback is strong By connecting a high resistance poten- limit to the number of tubes which may enough to overcome any negative feed- tiometer across the terminals of the be used, for the reason that tube noises back which may be taking place, con- filament battery and connecting the are always present, and with each tinuous oscillations will be set up and grid return circuits to the movable successive stage of amplification these howling will usually result. arm of the potentiometer, the grid noises are amplified as well as the signal. bias may be varied from a negative One method devised to overcome a to a Audio Frequency Amplification positive coupling between two circuits positive value, making it possible to AUDIO is to provide a separate source of negative obtain any adjustment between the frequency amplification, as feedback to overcome or neutralize the extreme negative and positive which before mentioned, is used to in- may be desired. By this arrangement, crease the volume of the signals after effect of any positive feedback which the detector. may be taking place between two cir- the grids may be made either negative they have passed through cuits. or positive with respect to the negative (Turn to page 67) In this method a small, three -plate variable condenser is so arranged that one movable plate may be moved in front of one or the other of the stationary plates which are insulated from each other, or it may be moved partly in front of one and partly in front of the other. The movable plate is connected to the grid of the first amplifying tube and the stationary plates are connected to the plates of the second and third tubes, respectively. This arrangement is used in resistance coupled amplifiers, as in this type, and each succeeding stage is reversed in phase. By changing the position of the movable plate of the condenser, one point of adjustment may be found where the feedback effect will be absolutely neutralized. Other positions of the movable plate may be found where the feedback may be either made negative or positive as desired, which makes it possible to control the feedback at will. In the same way, Fig. 3. this method may be applied to trans- The potentiometer method of controlling the feedback is shown in the diagram above. RADIO AGE for May, 1925 The Magazine of the Hour 9 Consider your Neighbors with This "QUIET" REGE\ERATOR BY ARTHUR B. McCULLAH

1111111111111111IIII IIIII IIIII IIIII IIIIIIIII111111111111111111111IIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIII IIII IMI 1111 11111111 111 1111111111111111111111111111111111111111111 111111111111 1111111111111111111 IIII 1111

.------111111111111111111111111 1111111111 111111 IIII 111111 IIII 1111 IIIII IIII 1111111111 II 11 11 1111 11111111111111111111 i l l 1111 11 II IIII 11111111111 II 111111 IIII !III III 111111111111111111111111111111111 IIIIIIIIIII IIIIIIIII IIIIIIIIIIIIIIInIIIII 111111111111111 A front view of Mr. McCullah's much -discussed radtation- minimizing receiver. After a series of tests, Mr. McCullah believes he has nearly approached the ideal regenerative set with this four -tube hookup.

THE purpose of this article is not to primary ana a secondary of (95) turns introduce a new circuit into the and the same size wire with which the radio folds for no good reason, but A Step Toward a antenna coil is wound. There is also a to introduce an old circuit with some of tap taken out at the center of this wind- its disadvantages overcome. Non -Radiating Set ing. Regeneration is obtained with a The regenerative set can truly be small variable condenser. It issometimes called the "Old Reliable." However, the high plate voltage as compared to known as the Rice Circuit. The primary conditions have grown up around it that the plate voltage of a detector tube. coil is wound on a smaller bakelite tubing have made it a burden to the community This, of course, makes for a more power- so it will make a snug fit when it has a at large. Our last trans -atlantic test ful oscillator. A general rule may be winding on it. In the circuit diagram it proved that the radiating receivers were stated that any set that goes into the will be noticed that there is a small fixed doomed. Not only is the regenerative state of oscillation will radiate energy condenser in series with the regenerative set a menace to society, but the many unless some method is used to prevent condenser. This is because of the fact varieties of radio frequency amplifiers the energy from leaving the set; i. e., in that the so-called regenerative condenser that go into the state of oscillation cause the super- heterodyne receiver the second has too high a zero capacity to prevent more trouble than a great many regen- harmonic system of wave- changing or the detector tube from oscillating at the erative sets. the Pressley system of preventing radia- lower end of the scale. Some have negligible quantity. prophesied that in a short tion to a The Choke Coil space of time the owners of regenerative Circuit Analysis sets will learn how to manipulate them AS THIS circuit is what is called a in such a manner as not to cause any In the set to be described, the antenna parallel plate supply, some method undue hardship to their neighbors. Time coil has (53) turns of Number twenty - must be used to keep the radio frequency has not borne out this prophecy, and four double- covered green silk wire. energy out of the plate supply. This can some method must be presented to the There is a tap taken out in the exact easily be done by inserting a small honey- fans so they can build sets that will not electrical center which is at the (26M) comb coil in series with the plate lead radiate and at the same time be elec- turn. This is the antenna tap. The pur- of the detector. A coil of one hundred trically efficient, as well as easy to tune. pose of such close coupling is to prevent turns or more will do the trick. It might The users of most regenerative sets know the first radio frequency amplifier from be added that this choke may be made that by making their sets oscillate they oscillating. There is a second method by winding one hundred turns of the will cause interference, but they con- that is not always needed, but it is put same size wire with which the other coils tinue to use such a practice because it is in for the few that might find it'necessary. are wound, or if some smaller wire is easy to find stations by the beat note It will be noticed that there is a .0005 handy, use it because it will make a more that is produced in their sets, as well as variable condenser tuning the antenna compact coil. The form for winding such in every other set in the neighborhood. coil and a .00035 condenser tuning the a coil can be had from an old spool. Some Criticism Undeserved detector circuit. The reason for this is The usual precautions should be taken that in designing a set, practically every in selecting the audio transformers. AS SAID, before, the regenerative set builder will have an antenna of a differ- We need not go into the details about comes in for a lot of criticism that it ent capacity, which would change the them, as they have been discussed at is not entitled to. The super- heterodyne wavelength of the secondary of the first length in these pages before. If the causes a great amount of trouble that radio frequency transformer to a great ex- builder wants to go to considerable work, the much abused regenerative set is tent if the tuning condenser were a .00035 he may use filament control jacks and accused of. The radio frequency am- condenser; hence the .0005 variable. put a jack in the plate circuit of each plifiers in many sets radiate more energy The second radio frequency trans- tube with the exception of the radio than regenerative detectors, because of former consists of two coils, a (24) turn frequency amplifier. 10 RADIO AGE for May, 1925 The Magazine of the Hour

III II II IIIIIIIIIIIIIIIIIIIIIIII III II IIIIIIIIIIIIIIIIIIIIIIII IIIII II III 1 IIIIIIIIIII11IP111111111111111111111111111111111IIIIIIIIIII IIIIIUIIIIIIIIIIIIIIIIi III IIIIIIIIIIIIIIIIIIIIIIIì11I11I11I11111I il IIIIIIIIIIIIIIIIIIIIIIIII111111II IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIV'= While the choke coil is very easy to build, to make the entire job one of simple assembly, it would be easy to purchase one 100 -turns honey -comb coil. For those who want to build their own choke coil, a very nice job can be made of an ordinary thread spool. Wind on one -hundred turns of No. 24 wire in most any fashion. The ends of the wire can be brought out to two screws at one end of the spool. No trouble should be experienced in constructing this set, as there are no "trick" parts, nor are there any moving coils that would cause the builder with a limited number of tools any difficulty.

111111111U111111111111IIII III IIIIIIIIIIIIIIIIIIIIIIIIIII III IIIIIIIIMIYWWYUIIIIIIIIWIi1M11111111111111111111111111111111111111111IIIII IIIIIIIIIIIIId1Il1I11111I1111IIIIUIII IIIIIIIIIIIIIIIIIIIIIII11111111111111111111111111111IIIIIIIIIW51111111111111IIir Oscillation On First Tube Panel view of the "Quiet Regenerator. There are two major controls, a .0005 variable SOME trouble has, been experienced condenser tunes the antenna coil while a .00035 condenser tunes the detector circuit. with this circuit on some antennas, due to the first tube oscillating. The The much important "C" battery is 1 / lb. No. 24 D. C. G. S. first tube on some occasions broke into left out of many sets. This is not the 1 Neutralizing condenser. oscillation in sympathy with the detector case here, however, for it is particularly Construction tube when it oscillates or is about to when using advantageous 199 tubes as IS an old Chinese proverb oscillate. we do in this set. that "One fTPicture is Worth 10,000 Words." The only remedy for such a trouble is Only one rheostat is used, as 199 tubes The picture will tell in the best way to neutralize the radio frequency tube. work best at three volts. It does not take how to lay out the set. - Neutralization is very easy in this cir- four rheostats to adjust the tubes to The antenna coil should be wound on cuit, as there is only one tube to neu- three volts, as the tubes have the same the tralize. The first thing to do is to discon- characteristic. center of the bakelite. The most accurate way to do this is to drill a small nect the antenna from the set. Set the List of Materials hole in the tube, equidistant from both first dial at about thirty on the dial, and second dial until the click 1 7 x 14 inch panel. ends of the tube and wind on two coils, then turn the is heard in headphones, which indi- 1 7 x 13 inch panel. using this as the starting point for both the cates first tube is oscillating. 1 .0005 variable condenser. windings; that is, 26% turns on both the This, of course, is done with the regen- 1 .00035 variable condenser. sides of the center. If the same type of 2 Low ratio audio frequency trans- condenser is used, the coil will be mounted erative condenser set at zero. Now, by formers. on the back of the condenser. This first adjusting the neutralizing condenser, the 4 199 tube sockets. coil should be at right angles to the first tube can be made to stop oscillating. A test to see whether the first tube is 1 Grid leak and condenser. baseboard. oscillating or not is to turn the regener- 1 Rheostat. The second radio frequency trans- a slight amount and then 1 4 spring jack. former is mounted on the back of the ative condenser turn the second dial back and forth over 1 2 spring jack. condenser in the same manner as the the point where the tube oscillated before. 1 On -off switch. first, except that it is parallel to the 1 Chelton variable condenser. baseboard. In other words, it is at right 1 .0001 fixed condenser. angles to the other coil. The primary coil Note by Technical Editor -Builders of this should remember 2 Bakelite tubing 31/ inch long, 2 is wound on the small coil that is one inch circuit that any im- in long, properly neutralised circuit, regardless of inch diameter. and it has twenty turns of wire on the means adopted for neutralisation, can 2 Bakelite tubing 1 inch long, 1 inch it. The secondary coil, as said before, send a weak current into the antenna circuit in diameter. has a tap and may be wound the same as and at close range prove bothersome to a 2 Dials. the primary coil, only it has 53 turns, or neighbor. Be sure the r. f. tubes are com- 7 Binding posts. 2614 each side of the center tap. pletely neutralized before going ahead.

The wiring layout of Mr. McCullah's four tube receiver. Regeneration is obtained with a small variable condenser. In the diagram above it will be noticed that there is a small fixed condenser in series with the regenerative condenser, far the reason the so- called regenerative condenser has too high a zero capacity to prevent the detector tube from oscillating at the lower end of the scale RADIO AGE for May, 1923 The Magazine of the Hour 11 Proper How Knowledge to Make of Tubes' Capacity

. a and Worth Will Save Vacuum Fan Much Trouble in Tube Operation Tester of His Set; Many Ways By H. FRANK of Operating HOPKINS 'Tester Shown

AGREAT many radio Fig I. A front view of the vacuum tube tester, which can be results equal in quality as fans of today are con- made by any fan. Each part is so placed to give maximum effic- that applied to them. If stantly asking how iency, and no parts are used that will not be necessary. The tester the vacuum tube fails to they can improve on their is compact as well as attractive, and may be constructed for port- deliver, the output will equipment and how they able or stationary use. suffer in both quality and can reach out and bring volume. If the tubes do in the distant stations strong enough to few instruments, he has a great field open not match up; that is, if they do not have work the loud speaker and yet maintain to him, and the writer is sure that when characteristics similar to one another, maximum tone quality. Knowing that he meets problems beyond his capacity, they cannot be expected to pull together to add amplifying units tends to distort which will be few, he need only seek the and produce satisfactory results. the signal and produce excessive local counsel of authors of technical radio The tube problem becomes more com- noises, therefore other means to attain articles, and they will be only too pleased plicated day by day as new tubes are efficiency with the present equipment to help him out. put on the market. Not that these new are constantly in demand. The most vital parts of a receiving set tubes are inferior, for their quality is Efficiency with matched parts is a big are the vacuum tubes. They are the every bit as good as can be obtained, but step toward getting the utmost out of a heart of the system. When they cease to their characteristics are not the same. set. A way to match and measure the function efficiently, all of our other efforts One brand may not have as great an various parts of a receiving set was de- are in vain, our matched parts cannot impedance as another; maximum ampli- scribed by the writer in the February produce that which is not applied to fication may be obtained on one make of RADIO AGE, when a slide wire bridge them and they can only pass and produce tube at a different plate voltage or grid was outlined. From the number of in- bias than on another. Such tubes can- quiries and reports of results obtained not be expected to "co- operate" when the with that instrument, it is evident that WIRING TABLE same plate voltage and grid bias are the set -builder of the present is more Run One Lead from TO- applied to them. Therefore, some meth- in Binding Post B90 Switch point No. 4 interested the art and theory of radio Binding Post B 67!5 Switch point No. 3 od of matching tubes or determining just than in just putting a bunch of parts Binding Post B45 Switch point No. 2 where their critical point lies is obviously Binding Post B2215 Switch point No. 1 together to build a receiver and listen to a Binding Post B- Binding Post A + necessary. few programs. Binding Post B- Terminal 100 on PF Pulls Others Down He is an experimenter, gaining knowl- Binding Post B- Switch point -I- Binding Post A + Terminal F+ on T wear out, too. The edge in addition to amusement. Often- Binding Post A - Switch point - VACUUM tubes Binding Post A - Terminal No. 10 on wine as everything else, and as it times he contributes valuable informa- PF tion to the radio science. It is to this Binding Post C + Terminal No.1 on GP passes its efficient stage, it pulls all of Binding Post C+ Terminal No.0 on BS the others down with it by making it type of radio fan that we look to for the Binding Post C- Terminal No.3 on GP future development of radio, for he accom- Terminal No.0 on PS Terminal No.1 on BR necessary to increase the filament volt- Terminal No.0 on BS Terminal ton GM age to obtain a satisfactory output. plishes as much as the professional radio TerminalNo. 2 on GP Terminal G on T engineer. Terminal G on T Terminal No.2 on GS The others consequently age very rapidly, Terminal No.2 on BR Terminal + on MA making it necessary to replace all of them A Little Study Necessary Terminal No.2 on BR Terminal No.4 on TS Terminal - on GM Terminal No.1 onGS in a short time instead of replacing just IT is not necessary that one have an Terminal - on MA Terminal P on T one of them when it passes its useful Terminal No. 2 on R Terminal No. 10 on advanced education in electricity or PF period. This was described in the radio engineering to apply science in his Terminal F - on T Terminal 1 on R article entitled "Regulating Filament Terminal F + on T Terminal No.3 on TS experiments, or to know why he gets Terminal + on TS Terminal + on PF Energy" in the April RADIO AGE. certain results. With a little study and a One such case would cost the fan 12 RADIO AGE for May, 1925 The Magazine of the Hour

O- /O -/DO SCALE .30" VERNIER 400 `-/PoTENT/AMETEX VOLT fIETER RHEOSTAT. V T5 ti t PF

/o

/O -O /O SCALE VOLT MFTER.

300o" GRAPH /re RNEO STAT. .W/,P /NG D/, ,c',?M 469C7/!/M TUBE TEST SET.

Fig. 2. Wiring diagram for Air. Hopkins' tube tester. This layout is so simple any radio fan can follow it, and yet its efficiency and worth are unlimited. Voltmeters of the highest rating were used in this unit. almost as much, if not more, than a the prospective builder to understand 6 Switch points, BS 1, 2, 3, and 4. good tube tester. This would not be the place of the parts in the circuit and to PS-I -and -. so if inconveneint it would only happen simplify the wiring. 10 Binding posts, B90, B67 1 -2, B45. once, but it continues to happen, while A case or cabinet 8 1 -2 inches by 11 B22 1-2. B- ,A+,A- ,C+,C+ -,and the investment in a tube- tester is like inches and 5 inches deep will be required C -. insurance on your tubes, in addition to if this is to be a portable set; or just a Miscelihneous mounting screws, ter- the benefits you will reap in acquiring panel 10 inches by 14 inches by 3 -16 minals, wire and solder. more knowledge about your equipment. inches thick with the necessary mounting Wiring In this way you will be able to weed out brackets if it is to be used as a permanent the Set the weak, inefficient tubes and match the fixture. The panel for the case will be `lkTHEN all of the instruments have `` vv been secured good ones for efficient operation. 8 1 -2 inches by 11 inches by 1 -8 inches or and the panel laid The tube tester to be described is not 3 -16 inch in thickness. It will be drilled out and drilled with the instruments expensive. Its total cost is not much to mount the equipment as shown in the mounted on it, the next step will be to wire more than six dollars more than the cost photograph accompanying this article. it up. The method to do this is with of the meters, and these instruments may No dimensions are given for drilling the Number 14 B and S gauge rubber -covered be purchased from any reliable dealer panel, as there is a large selection of stranded wire, each wire having a ter- at about seven dollars each. equipment, all different in shape, and all minal soldered to each end. These term- The meters used in the set to be de- can be used with equal success. Accord- inals will be securely bolted to the posts_ scribed were the best that could be ob- ingly, the size of the holes may vary, on the instruments. Care should be tained for this purpose, and they are but the layout of the panel is not altered, taken to see that the soldering is secure standard equipment. In listing the bill of nor is it difficult. and makes a good connection, and that materials for this set, all of the parts are the lugs and terminals are clean and have given a designating letter or sign, which The Parts of the Instrument (Turn to page 56) is used throughout the article to enable 1 Two scale voltmeter. (0 to 10 and 0 to 100 scale.) PF for plate and filament voltage. 1 Voltmeter (10 -0-10 scale) GD'I for measuring grid bias voltage. 1 Milliammeter (O to 30 scale) MA for measuring plate current. 1 Jack switch, GS, for grid voltmeter. 1 Two way transfer switch, TS, for PF meter. 1 30-ohn vernier rheostat, R, for fila ment control. 1 3000 -ohm graphite resistance, BR, for "B" or plate battery control. 1 400 ohm potentiometer, GP, for grid bias control. 1 201 typa socket, T, with metal shell. 1 Adapter for 199 tubes (If required.) 1 Adapter for WD type tubes (If required.) Fig. 4. Typical grid characteristics for Fig. 3. A typical plate characteristic 2 Induction switch levers and knobs, 199 typpe (3 volt) tubes at 45 -80 and 90 curve for the 199 type (3 volt) tube. BS, and PS. volts "6" battery. RADIO AGE for May, 1925 The Magazine of the Hour 13 A POWER SUPPLY Receiver By BRAINARD FOOTS

Does the ap- pearance please you? "Two hand" tuning control, with vernier dials, an R. F. coup- ling adjust- ment for sensitiv- ity and the crys- tal control- handle form the only visible parts of the receiver. Station calls arel ettered on the dials. A push switch in the power line turns the set on and off. How to Make a Receiver that Draws Both Plate and Filament Voltage from Lighting System; Not for DX

THE application of alternating cur - or zincite and tellurium, a detector that rent for supplying energy for both Pictures by the Author is rugged and long -lasting may be easily filament and plate circuits of a obtained. The dual mineral type of receiving set is distinctly new and rather detector is ideal for such a receiving set, "tricky." It is comparatively easy to HOWEVER, by correctly arranging inasmuch as its adjustment is made in a devise a rectifying system for furnishing the "grid return" leads, the hum second and that adjustment is held for satisfactory plate voltage to replace the ordinarily caused by 60 cycle lines is long periods of time -often several weeks dry cell type of "B" batteries, but the balanced out to such an extent that it on end. addition of the house lighting system is scarcely noticeable. There are, how- The amplifying tubes can, with per- for lighting the tubes as well is a more ever, some limitations upon the types fect success, be lighted on A. C., so that complicated matter. of circuit which may be successfully the set may employ tubes for amplifying However, the incomparable conven- used with the A. C. supply system, and purposes in practically any combination, ience of a never -failing power supply moreover, upon the extent of the set's provided the detector be a crystal. To appeals to everyone. Dead batteries receiving range. These requirements gain the best results, the circuit should usually show up just when you've invited tend to restrict the use of the system not be reflexed, since there are certain the next -door neighbors in for a special to listeners who care more about the uncertainties about reflex sets that often program of Metropolitan singers, or reception of programs from the nearer cause trouble when run on alternating during the Sunday evening concert. stations and who are more interested current. The most satisfactory all - And "B" batteries must be frequently in perfection of musical reproduction around circuit is a combination of one replaced as they become exhausted. than they are in the search after far away step of radio frequency, a crystal de- Inasmuch as the alternating current broadcasts. tector and two steps of audio frequency, can easily be changed to direct current A tube detector, unless it be supplied with no provision for headphones. of any desired voltage for the "B" cir- with filament current by a storage For Loud Speaker Only cuit, the "B" voltage supply is composed battery or separate dry cell, is ruled out of direct current, as usual, with a battery. from the start. This means that a N OTHER words, the completed set But for the filament, on the other hand, crystal detector is essential. From the is one intended solely for loud speaker rectification of suffcient current for tube standpoint of extreme sensitivity, this is reproduction. It is a simple set to illumination would entail a large amount certainly a handicap, but for clarity of operate, with two tuning controls and of rectifier and filter apparatus that would reception no one can question the crys- one scnsitivity control. There is also make the storage battery and charger tal's superiority over the tube for detec- the crystal detector adjustment knob the more logical and convenient filament tion purposes. And with the plentiful which must be touched occasionally. power supply system, to say nothing supply of new crystal detector stands Stations within fifty miles are considered of the cost of such equipment. comprising either zincite and bornite "locals" when received on a fair outside 14 RADIO AGE for May, 1925 The Magazine of the Hour

capacity plate on which the house tele- phone is placed. The sloping type of cabinet is chosen for reasons of tuning convenience and better illumination of the dials, and for the better appearance as well. To house the necessary apparatus, the baseboard méasures 20 inches long by 12 inches deep. On it are the tuning apparatus, except condensers and de- tector, the audio amplifier, the "B" voltage rectifier and the filament current supply system. Thus, the only external connections or parts needed are 1, The aerial; 2, The ground; 3, The loud speaker; 4, A cord and plug to the base receptacle or other lighting socket. To avoid ugly wires in front, the speaker leads are inserted through the rear and at the left end of the board, the flexible cord is placed at the rear center, while the aerial and ground wires emerge at the rear right. A push switch is inserted in the flexible cord at about a twelve -inch distance from the cabinet, How the baseboard is laid out, showing the wiring completed except for the coils. for turning the power on and off. The layout isn't so large, when you consider the fact that no external "A" or "B" bat- The Parts Necessary teries are necessary. The base measures 12 by 20 inches. SO LONG as high grade apparatus is antenna, and those within twenty -five for DX work like the super- heterodyne selected, there are no special require- miles are "locals" when a small indoor and various other "dynes." ments as to the parts selected, with the aerial is used. The selectivity is very One illustration shows the baseboard exception of the A. F. transformers. satisfactory, so that some distant stations of a power supply receiver built for use Three of these are used in the "B" may be heard while locals are on the air, with a cabinet. Another view shows rectifying system and they must be and quite a lot of pleasing DX work how the completed set appears and gives rigidly assembled, with clamps or ma- can be accomplished when locals do not some idea of its attractiveness and simple chine screws tightly holding the lamina- interefere seriously. This means that control. The circuit selected is presented tions of the core at several points. If while the set is chiefly meant for local as a result of a great deal of experiment- you can wiggle the core pieces with your reception with perfect clarity and plenty ing in search of a circuit with plenty of finger, they cannot be used for the "B" of "pep," DX stations are also within sensitiveness and adaptable to all sorts part of the set, though they may be used reach, though not to the same extent of aerials, from a long high wire over 150 for the audio amplifier well enough. as with a receiver expressly intended feet from end to end down to a mere (Turn to page 48)

TO 110 V.-A.C. G. A jo SDEAtc.IR t Au()lo TRANS.

CRYSTAL BF

Complete wiring for a receiver operated on the A. C. house current. The only battery used is a 4 1 -2 volt "C" battery -this being included in the set. There are five tubes in all; it's a three tube and crystal detector set, the extra two tubes furnishing the rectified current for the "B" voltage. RADIO AGE for May, 1925 The Magazine of the Hour t. Now's the Time for a Radio I louse-Cleaning !' By PAUL GREEN

An All-Around Overhauling Needed If Your Set is to Work Efficiently This Summer Jr

FOR FIVE months or more, radio propose doing? Desert your old stand -by? should hang tree and clear of other reception has been good. Aside And just when it needs your attention, objects. It must be well insulated where from charging the "A" battery, too. it enters the building. Be sure that the most of us have given our sets little or Blame joint between the lead -in and aerial is no attention since last Fall. Now, how- Weather Gets the a good one. ever, we hear on every hand complaints THE average set has seen a total of There are a number of changes that of reception falling off. By this time not less than six hundred hours' may have taken place in the set since next month a large majority of radio service since last it received any real last Fall. Unless the joints were soldered listeners will have pessimistically ac- attention. During that time batteries, with rosin core solder or carefully wiped cepted the situation as unalterable and contacts, joints and tubes have under- after soldering, many of them will be let it go at that. gone changes. Even if \Vinter were to found corroded or coated with a copper In spite of this, broadcasting stations continue, these parts would need atten. salt. Flux often spreads to the panel have been for many months planning tion. But, in common with many other and forms a partial short circuit, the wonderful programs and greater power fans, you probably have overlooked effect of which becomes more and more for the coming Summer. If reception examining your set, charging the weather apparent as warmer and damper weather continues to grow poorer as the season with the "falling off" instead. approaches. Clean such parts with advances, will all this planning accom- Certainly, with all these wonderful benzine and alcohol. Unless the rotors plish anything? Isn't it just so much radio programs ahead of us, it is very of your condensers are provided with wasted effort? you ask. Well, perhaps worth while to do what we can to assist flexible "pig tails," it is well to clean the we have formed hasty conclusions as our sets to give us their best. Following points of contact with fine emery cloth. to the effect of warmer weather on re- are some of the complaints to which a Dust between the plates with a pipe ception. Let us see. set may be subject at this time of year, cleaner to remove dust particles and Do you recall, last Fall, when you put with hints for remedying the complaints. lint. If left in, they tend to collect the old set in trim for the Winter, how An aerial which, perhaps, gave very moisture and cause leakage between among the things you did, perhaps you good service all Winter long may now plates. This cuts down volume and purchased a new set of "B" batteries hang too close to trees and shrubbery. makes the set noisy. and a tube or two and just for luck re- As the foliage comes out, the absorption Broken soldered some of the joints. You knew problem grows more serious and the Look for Joints that others were getting results; there- aerial must be given more clearance. ITH a pair of phones on your ears fore, your failure to do so argued the An examination will usually show that W and the set in operation, go over need of attention to your set. Well, it can be rehung more advantageously. it for broken joints. Tap each point anyway, you got the set to "perking" - While doing so, see that the insulators separately with a lead pencil. With the and it has continued to do so for several are clean and free from carbon deposit. head -set still on, test each movable part. months. Well, here we are "at the end If they are of a porous design, change If sudden clicks are heard, it is a sure of our radio season," and what do you them for the glazed type. The lead -in indication of broken joints or loose con- 1

16 RADIO AGE for May, 1925 The Magazine of the Hour juvenating their tubes. Tests with this equipment reveal some very interesting facts. Tubes which have long since passed their period of usefulness can be brought back to apparently full normal. This also applies to tubes which have been paralyzed by excess filament volt- age. Frequently brand new tubes will show a marked improvement after treatment. In a number of tests, rejuvenation has made the tube noticeably superior to new tubes. Paralyzing a tube and bring- ing it back to life has been repeated as high as thirty or forty times without noticeably ill effects of any kind. Heretofore, our tubes, like dry batter- ies, were discarded when their effective life had passed. Now that we can re- charge them just like storage batteries. Let's make this a real radio Spring and Summer and enjoy the wonderful pro- grams planned for us. And while you're cleaning up and tightening up your set, you might cast an eye around the room in which it is The picture shows a good example of how neat wiring hould be accomplished. A located and tidy that up a bit. Nothing compact wiring job like the above will withstand the tests f time. Unless your set joints so irks a well- meaning housewife as to were carefully soldered, the chances are that warm weather will have corroded them, The find hubby's or son's radio apparatus remedy is to clean such parts with benzine and alcohol. Brush between plates to remove dust, which will cause leakage if you do not watch out. strung all over the bedroom, dining room, kitchen, or wherever the set hap- pens to be located. tacts. In case of loose joints, re- soldering PRACTICALLY everyone of us has So for the good of all dispositions con- will correct the trouble. Tightening noted the instructions which come cerned, clean out all unnecessaay parts with tubes, for rejuvenating nuts will usually correct the other. them. A and stow them away for future use. And Those of us who are using storage "A" few of us have tried these instructions, while you're doing that, see that your batteries know that they must be re- but so far as the writer's experience goes, aerial lead -in from the set to the window, charged at intervals. We have corne to no one ever "brought his tubes back" and the ground connection are in good by such a procedure. is recognize the symptoms which say - This accounted shape, for these vital factors of a set's "low battery," and so little need be said for by the fact that very few fans have operation, when not inspected from time on this score. But it is usually a fact the proper instruments for regulating to time, may develop faults that do seri- that "B" batteries are allowed to get or measuring the applied filament cur- ous damage to the receiver. low before new ones are purchased. rent, (Note? Mr. Green will be glad to should be tested frequently and supply They A Step Forward detailed information regarding the soon as the voltage has dropped ten tube as Within a short time instruments will rejuvenator to all readers twelve per cent, thrown away. Under of RADIO AGE or be made available to all fans for re- who will address him care of this magazine.) such `conditions it will usually be found that the amperage has dropped to a very low figure. For this reason, it is not safe to allow the "B" battery to fall off much more, especially if yours is a set having more than two tubes. Like the storage battery, the tube becomes run down and after a Winter's use it is in no condition to detect properly and amplify the weaker signals of sum- mer -time. The tubes are responsible for much of the falling off that we have attributed to the weather. The effective life of a tube is not de- termined by the length of time it can be used without burning out. Long before this occurs, most tubes cease to be efficient. To offset this gradual falling off, the filament is burned brighter. This still further hastens the tube's demise. Is it at all strange, then, that as Spring passes and Summer comes we Ind our sets almost useless so far as coping with the more difficult broadcast conditions is concerned? So much for cause and effect -we have remedied the other troubles; now what can we do for the tubes? When it was said that the tube, like the battery, runs low, the analogy should have been carried one step farther and How a tube rejuvenator the statement made that the tube, like works. Such an instrument will renew the 201A and 301A as well as the ÚV199 and C-299 tubes in less the battery, can be recharged. than eleven minutes, it is claimed. As no mpws are necessary, hosts of fans will find this set easy to build. RADIO AGE for May, 1925 The Magazine of the Hour 19

An unusual photo showing a rear panel view of Mr. Calcaterrá s 8 -tube super -heterodyne. Note the compact arrangement, which though utilising every inch of space, is not crowded. A PRACTICAL SUPER4 JET A UNIQUE 8 -TUBE OUTFIT ON AN I8-INCH PANEL

GOSSIP for months past has been THE instruments have been very care- to the effect that the super- By Joseph Calcaterra fully designed to permit mounting heterodyne circuit, the "king of in a small space, without interfering all radio receivers," has been taken out electrically with each other, and the of the mystic precincts of the laboratory BILL OF MATERIALS creditable performance in this respect is, and made into a practical proposition FOR THE SET therefore, not to be considered surprising. for the average set user. Yet it cannot Reference 1 Front Panel, 7 "x18 "x3 -16 ". It must not be forgotten, either, that of gossip has been Numbers 1 Sub -Panel, 7 "xl7 "x1-8" even in super -heterodynes, short wires be said that all this 1 Binding -Post Panel, 1Ii "x17 "x accompanied by any too much definite 3 -16" are better than long ones, and close I Cabinet for 7 "x18" Panel, 7 or 8 information in the way of diagrams and inches deep. mounting permits short wires. Add to panel layouts which- would enable set 1, 2 2 Low -loss Variable Condensen, this technical advantage the great use- .0005 mfd. builders to turn out a super to grace the 3 1 Rheostat, 30 Ohm. fulness of an 18 -inch set as Compared parlor rather than the laboratory -with 4 1 Rheostat, 6 Ohm. with a 40-inch one for traveling purposes to consistent reliability as well 5, 12 1 pair Shelf -Supporting Brackets. in the Summer time, and the set here respect 6 1 Midget Variable Condenser. as appearance. .000045 mfd. described needs no further recommenda- Supers have been in general great 7, 42 2 By -pass Fixed Condensers, 1 mfd. tion. 8 I Brass Angle Bracket, each leg 1 eaters of battery current, as well as inch long: hole in each leg Tone is Paramount occupiers of an ungainly amount of inch from the bend. (Standard It should be remarked, however, that brass bracket obtainable at most space. In the attempt to cut down the radio or hardware stores.) tone quality has been considered para- battery consumption, complications have 9, 11 2 Single- Circuit Jacks. mount throughout this design; while been introduced, such as reflexing, which 10 I A Battery Switch. the selectivity- noted is fully- up to the stand- 13 1 Fixed Condenser, .005 mfd. are hardly improvements from the 14. 16 2 Laboratory -grade Audio Trans- best super- heterodyne practice, it is point of simplicity. formers. believed that the tone quality obtainable, is 15, 17, 18, The super here described unique 20, 21, 22, 8 Sockets for UV -199 or C -299 even with distant stations, is a distinct in at least some of these respects. Em- 23, 24 tubes. advance. Two features contribute large- the full eight tubes of the 19, 25 2 Fixed condensers with grid leak ly to this -the use of broadtuned bodying mounting clips.00025 mfd. standard Armstrong circuit, with each 19 1. 2 megohm grid leak. transformers in the intermediate stages, transformer separate so that it can be 25 1, 5 megohm grid leak. eliminating the necessity of delicate interchanged independent 26 1 Type R -130 Radio Frequency "matching," and the use of laboratory - tested and Coupler. of any other part, the entire set mounts 27, 28, 29 3 Type R -110 Long Wave Radio grade audio transformers. In spite of neatly on a 7x18 inch panel and a 7x17 Frequency Transformers. this use of some rather high- priced parts, 30 1 Type R -120 10.000 Meter Tuned inch sub -panel, so that it fits any stand- Radio Frequency Transformer. the entire set can be built at an ex- ard 18-inch cabinet. And if some of the 2 Vernier Dials. penditure for parts (not including tubes. 31, 32, 33 3 Binding Posts with "Loop" veterans of supers of former years are marking. batteries, etc.) of not to exceed $75.00. inclined to look askance at the "crowded" 34, 35 2 Binding Posts with "C Batt-" Simplicity of control .is another point arrangement of instruments and ask marking. which has been carefully worked out 36, 37, 38 6 Binding Posts, one of each of questions about inter -stage coupling. following: in this design. Besides the two familiar the writer can only answer that such 39, 40, 41 Markings, "C Batt -"; "A Batt major controls, there are only three minor "A Batµ + ": "B Batt-", inter -stage coupling has simply not put B Amp. +" ones. Yet the sensitiveness is not per- in appearance. ceptibly less than that of any of the 20 RADIO AGE for May, 1925 The Magazine of the Hour

Rear view, layout of panel

Top view, layout of sub -panel

r ' k T I' T. 1! 42 13 T

41 40 39 38 37 36 35 34 33 32 31 - B+ B+ B- A+ A- C+ C- C- L o o p h 00, 00 O

B 22 I 5 Á24B' Á23 211 ',0:Á20 19 Á 18 12 ö._ 0 f 15 0 13 a B Bottom view, layout of sub -panel 41 40 39 38 37 36 35 34 ;", 33 32 31 0 o (e) o 0 0e o ® o 0

Building post panel layout-view from front of set, inverted RADIO AGE for May, 1925 The Magazine of the Hour 21

well - known, complicated supers; a loop antenna not more than 18 inches n diameter will bring in listant stations. The two photographs show the appearance re- spectively of the top and bottom of the set, and drawings are given which show the layouts re- spectively of the back of the panel, top and bottom of sub - panel, and binding -post panel. (See note at end of article.) Parts Shown by Numbers AWIRING diagram is also given, on which A bottom view of the super -heterodyne receiver, showing the wiring arrangement before the parts are the parts are identified installed, After studying this diagram and the others in this article, the fan should have no trouble in by the same numbers placing the parts. Every part is clearly marked by a number in the diagrams on the opposite page. used in the drawings. This circuit does not differ very much reversing some of the binding post screws three in series, or preferably a four -volt from the standard circuit; it has a special on the sockets. All of these posts which storage battery. Binding post 40 should method of loop connection by which a are shown on the sub -panel by slotted be connected to the 45 -volt B battery certain amount of regeneration is intro- screw heads instead of by knurled nuts terminal for the first and second detector duced, under control of a small variable are thus reversed, and the wires are tubes, and binding post 41 to the 90- condenser (No. 6 in drawing). This attached below the sub -panel. In some volt end of the B battery for the ampli- sharpens the tuning to a marked degree. cases other connections are made also fier tubes. Binding post 34 carries a All of the parts used in a super- hetero- on top of the sub -panel, a soldering lug dyne must, of course, be high -grade in being here inserted under the screw head 4volt negative C battery voltage to order to get the results one expects from for that purpose. The reversed terminal the grids of the two audio tubes, while 35 3 -volt the circuit. It is not necessary to use screws going through the sub -panel are post carries a grid bias to the the laboratory -grade audio transformers sufficient to fasten the socket to the intermediate frequency tubes. shown in the pictures, but since these panel without using additional screws At the other end of the binding post are larger than standard transformers, for the purpose. panel are the three posts for loop con- the latter can be mounted in the same After all of the parts and binding posts nections. Post 32 should connect to a space with no difficulty whatever. are connected to the three panels, and tap on the loop such that one -fourth of The holes in the sub -panel, through the binding -post panel is attached by the total turns on the loop are included which wires are passed when making metal brackets to the sub -panel, the between posts 31 and 32. connections between terminals located greater part of the wiring can be com- To operate the set, turn on the battery above the sub -panel and others below pleted to best advantage before attach- switch and turn the rheostats about the sub -panel, have been made conspicu- ing the front panel. It is best to begin three-fourths of the way on. Set the ous by being blackened. These holes with all of the wires which can be con- small condenser, No. 6, at its minimum are marked by lower case or "small" nected on top of the sub -panel assembly. capacity and begin tuning with the two letters to distinguish them from terminal Next the wiring on the underside of the large variable condensers. When the markings. These holes are not all shown sub -panel should be completed, and set is working, gradually increase the in exactly the best position- in the draw- then the wires which run through the capacity of condenser No. 6 to sharpen ings here given, as a few have been sub -panel, between terminals located up the tuning, but not enough to throw shifted slightly to bring them into view. on opposite sides of it. The front panel the detector into oscillation. Rheostat It will be noticed in the photographs is then attached and the remaining wires 3 should be turned on as far as possible t hat there are very few wires visible from connected. without causing loss of clearness of tone, he top of the set, and this feature adds At one end of the sub -panel are the and rheostat 4 should be turned down

8 reatly to its appearance. The effect is eight battery terminals. The A battery as low as possible without losing volume. c btained chiefly through the device of may be either six dry cells connected (See note below)

G P G P G P G P r G P 30 A25S g4

B A

A wiring diagram of the super -het. This receiver does not differ from the standard hookup of its kind, but it offers unusual tone quality, operating best in locations about 200 miles from powerful broadcasting stations. Note: Persons who desire to build this set can obtain from the author complete, full -size panel lay -out and detailed wiring directions. Enclose 10 cents in stamps to cover mailing cost, and address Joseph Calcaterra, care of this magazine. The author will be pleased to hear from persons who have built the set, describing re- sults obtained. 22 RADIO AGE for May, 1925 The Magazine of the Hour The Physical Significance of Tuning

By Dr. Frederick W. Grover

The Action of 1x ho is a prom- inent Member of the Department of Electrical Radio Waves Engineering o, Union College, Schenectady, N. Y., and recog- nized authority in your Set on the subject of radio wanes

EVERY radio fan knows what is period just as in the case of the string. volved in the vibrations of a sounding meant by tuning -in. You turn Whereas the pitch of the sound given body, let us consider the simple case of a dial on the receiving set until by the string (so many vibrations per a thin strip of steel, a foot long, clamped the sound is loudest. Without tuning, second) depends upon its length and ten- at one end in a vise. If the free end is only the local stations come in, and it is sion, so the pitch of the electrical wave pulled 'aside, we feel an elastic force impossible to separate one station from (so many kilocycles per second) depends resisting us, and this gets greater the another. We tune our sets as a matter upon the amount of inductance in its farther we pull it from the original posi- of course and naturally give little thought coil and the capacity of its condenser. tion. If now we let the spring go, the to the actual significance of what may The analogy between a sounding body elastic force causes it to return toward be regarded as perhaps the most basic and an oscillating electrical circuit, used the undisturbed position, and we observe of radio adjustments. for broadcasting, may be extended to that it will vibrate for a short time, send- I am asking your consideration of cer- the case of a receiving circuit also. If ing out pulses into the air. If we try tain analogies which may be pointed out you sing a single note forcibly into the a much shorter and stiffer spring, suit- between the actions in a radio circuit top of a piano, you will obser. e that one able for a harmonica, the vibrations are and those in the more familiar cases of of the strings faintly sings the same note more rapid and we hear a musical sound. sounding or vibrating bodies. Analogies after you. Investigation shows that the An explanation of the vibrations of are helpful in that they illustrate un- single string involved, if struck in the the spring is briefly as follows:-The familiar things by pointing their like- usual way, gives out this note and no spring is bent aside at the start, and when ness to things better known. However, other. Of the multitude of strings in the released, the-elastic force causes it to when we liken an electric oscillation of piano, all are practically unaffected, move. As it returns, the elastic force current to the vibration of a sounding except the single string whose natural diminishes, and by the time the spring body, or an electromotive force to a me- period of vibration agrees with the period has reached the original undisturbed chanical force, it must be remembered of the sound vibrations sung. Shout position, it has become zero. However, that they are not identical things. We another musical note, and another string the spring keeps on moving because of must use our imaginations subject to responds, while the previous one joins its momentum, and as it passes the common sense, and make some allow- the throng of silent strings. Evidently undisturbed position it begins to bend ance for points of difference. the sound waves of your voice have the spring in a direction opposite to the first, thus setting up an elastic force Decides Wavelength beat upon all of the strings of the piano, Pitch but are powerless to produce a notice- which works against the motion of the ASTRING instrument is tuned by able vibration except in the case of the spring, slowing it down more and more carefully tightening a string until, string which is tuned to the incoming until it comes to rest. The spring then when it is sounded, it gives off the de- sound waves. moves back, and the sequence of events sired pitch. The pitch of the sound is, is repeated. If there were no friction, however, the same whether it is struck, How It's Done the spring would make equal excursions plucked or bowed. \Ve say that the LIKE \VISE, the electrical waves pas- on both sides of the undisturbed position. string vibrates in its natural period. The sing out from a broadcasting station and once started, the vibrations would same is true of any sounding body. produce no appreciable oscillations in a never cease. Of course, this is never the Sound waves go off from it through receiving circuit, unless its natural period case; the vibrations die down gradually the air and the pitch of the sound deter- of oscillation is the same as that of the and the spring comes to rest, since with mines the wavelength; that is, the dis- incoming electrical waves. When we tune each excursion the effect of friction is to tance by which one pulse travels ahead a circuit to the electrical waves, it is reduce the distance traveled from the of the next. Likewise a radio circuit may just the same as though in the piano ex- central position. be set into oscillation by various means, periment we had worked upon a single The original work done on the spring but gives off electrical waves whose wave- string by tightening it or loosening it, in bending it aside is the sole source of length bears no relation to the method until it responded with greatest loudness energy the spring possesses, and when this by which the oscillation is produced. to the note sung against it. has been dissipated in overcoming the The transmitting circuit has a natural To get a clear idea of the actions in- (Turn to page 5V RADIO AGE for May, 1925 IVhat the Broadcasters are Doing

9 +

Pbo,o Cop=ri[hc br Drake Studio REMINISCENT OF THE FAR EAST- were the intimate, quaint talks broadcast recently from KNX, Hollywood, Calif., by Anna May Wong, diminutive Chinese movie actress who has made such a "hit" with the cinema fans throughout the country. Despite the fact she's a native Chinese, Miss Wong talks like a typical New Yorker. However, she is able to convey real Oriental atmosphere by lapsing into Chinese dialect and crooning the weird songs of her native land. 24 RADIO AGE for 1Iay, 1925 Il7tat the Broadcasters are Doing what the broadcasters it are Doing

WEBW Quartet Gains WJZ Requests Second "Best Host of Friends Announcer" Rating 'THE four imposing young men who BECAUSE of the large amount of are shown in the photograph on D public interest in the findings of the this page compose the famous Fair- Radio Voice Technique Committee at its banks, Morse & Co., Quartet at Beloit, "Dream Daddy" On Air recent meeting, Station WJZ has re- 1Visconsin, who broadcast almost every quested that the committee hold another Tuesday evening from WEBW, in con- for Uncle Bob meeting for the purpose of comparing junction with the Fairbanks -Morse Con- DREAM DADDY" Harry Davis, one the announcers of all stations in and cert Band. The quartet recently sang a of radio's pioneer entertainers and near New York City. The committee noon hour concert from WNIAQ, Chicago, one of the most popular jazz artists on recently listened to wax records of a rep- which many readers may remember the air today, is now enjoying a new role resentative number of announcers and having enjoyed. as "pinch hitter" for "Uncle Bob," voted Herbert B. Glover, of WJZ, as the Three Lees and a Dave make up this (Walter Wilson), who has been delighting best of those announcers. musical four. They are: Dave Mc- the kiddies during Bedtime Story Hour Great public interest has been shown Cullough, Leland Forman, LeGrande at KYW for the past few years. in regard to that decision, and station Warriner and LeGrande Brannen. Uncle Bob was ordered to take a pro- WJZ feels that the term "Best An- The first of the Lees is Leland Forman, longed rest by his physician, and Harry nouncer" should be applied only to the who sings second tenor and who directs Davis volunteered to take his place winner of research in which every an- the quartet. The other two Lees are while the kiddies' popular "Uncle" is nouncer has been examined. Charles B. LeGrande Warriner and LeGrande Bran - regaining his strength in California. Popenoe, manager of Stations 1VJZ and nen, singing baritone and bass parts. And Harry, who made the song WJY, has forwarded the following letter Dave McCullough, the Scotchman who "Dream Daddy" famous several months to the committee: sings like an Irish tenor, is the fourth ago, is doing well as the little tots' lullaby "1 am naturally most pleased that an member and ably handles the top tenor man from KYW, every evening between announcer of Station WJZ should have notes. 6:30 and 7. received the highest rating at the recent "Our Dave, "as his colleagues and thou- Davis has been with KY\' ever since meeting of the committee. The fact sands of listeners all over the country are it went on the air and his method of pre- that the winning percentage was only 66 calling him, sings more popular numbers senting popular airs is known from coast out of a possible 100 shows, however, than the other members of the quartet. to coast for its originality. that there is still much room for improve- who confine them- ment in the an- selves almost en- nouncing profes- tirely to classical sion. compositions. Dave is one of the Not a Competi- most popular en- tion tertainersin south- ern Wisconsin. "In view of the unexpectedly large Flappers who have amount been charmed by of public interest in this his sweet voice question over the air will no of who is doubt be disap- the best announc- er, I should like to pointed and stop suggest sending the station that the Radio - mash Voice Tech notes when nique Committee theylearn that Mc- conduct Cullough is another a hap- and more compre- pily married man. hensive He admits it him- rating of self. the announcers of stations in and Brannen Popu- near New York lar Reader City. I realize that LeGrande Bran - the committee, at nen, the splendid its recent meeting, bass singer, is also had no thought of a n accomplished identifying the musical r e a d e r. holder of the When the quartet highest percentage recently entertain- as the "Best An- ed from Chicago, Here is the famous Fairbanks -Morse Quartet which entertains the Jans regularly nouncer" and that he gave a reading from WEBW at Beloit, Wis. From left to rì ht7 Leland Forman, LeGrande Warriner, the findings were called, "The Dave McCullough and LeGrande Brannen. Dave McCullough, the Scotchman who sings of a purely scien- Game of Life." like an Irish tenor, sang on the Radio Age program from KY W, Saturday. April 4. tific nature." RADIO AGE for May, 1925 1Vhat the Broadcasters are Doing Q Here is a Station That Realizes That Many Listeners -in Are Women Radio for Milady at WNAC The First Aerial Millinery Show from This Popular Boston Station Results in A Flood of Letters from Devotees of Style The demure hat shown above was one of the "hits" of the Millinery Show broadcast from the Copley- Plaza Hotel recently by WNAC. By OLIVER JENKINS

WOMAN has been long accorded the privilege of chang- was received last December that WNAC was going up to ing her mind at a moment's notice. There are some 500 watts. people of the opposite sex who have little patience The improvement in the station's power now makes it with this whimsical trait of womankind, asserting that it is possible for it to thoroughly blanket the New England states. merely a convenient refuge. Programs for women have been constantly on the increase. It goes deeper than that, however. A woman's life from Each week saw a more elaborate progress in this direction. beginning to end has a great deal to do with the word, "adapt- It was the day of March 4 that the crowning triumph thus ability." She must be ready to adapt herself to all sorts of far was reached. WNAC, on that day and evening, broad- changes, even to that of changing her name. It is natural, cast for the first time in radio history, a real, honest -to- goodness therefore, that she yields easily to the tyranny of that most millinery show. The latest millinery for the coming Spring fickle of gods -the God of Style. and Summer season was talked over at length, and vivid Perhaps you are wondering what all this has to do with descriptions were given. All of the finest millinery artists radio. Well, Station WNAC, at Boston, claims that it has of America and Europe were represented at this greatest of a lot to do with it. And Station WNAC ought to know some- all millinery shows. thing about it, for this station was the pioneer among the All the Styles by Radio radio stations in the Hub of the universe. Long ago this popular Boston station decided that the THE place was at the famous Copley -Plaza hotel, and in woman radio -fan was not being catered to as was fitting, and the spacious salon during the afternoon and evening, plans were made for doing something along this line. Miss more than two thousand of the best-known hat designers Jean Sargent, whose voice is familiar to every New England looked over the models, discussed unusual creations and listener-in, probably about a year ago hit upon a novel idea. (Continued on Page 55) She went to John Shepard, Jr., owner of the station, and outlined the scheme sketchily. "Today," she said, "radio stations seem to have the belief that they must present programs which will please every variety of listener -in. All the way from jazz to grand opera must .be traveled on each day's program. This cannot last. Sooner or later stations are going to realize that specialization will do the trick much better." Women Have Radio Needs HE knew that there were many women becoming interested in radio. Furthermore, she knew that graphic descrip- tions of boxing bouts, business talks and stock reports con- tained little interest for the women members of most families. Something ought to be done about this. "Why not a special period devoted to women each day ?" she demanded. "And what could you put into that period ?" was the ques- tion asked her. "Oh, all sorts of things. Cooking classes, style talks, advice on interior decorating, gardening -the subjects would be endless." So the idea was tried out one morning over the radio. The result was surprising. Letters poured in from all over New England, filled with praise and demanding more such periods. It was too popular to remain cramped in an hour's period, however, and soon several hours a day were given over to the women fans. Even so, the station was handicapped in being Here is one of those latest broad -brimmed hats which able to cover only comparatively small territory with its Miss Jean argent described from the style show 100 watts; imagine the joy and excitement, then, when news microphone for the New England flappers. 26 RADIO AGE for May, 1925 What the Broadcasters are Doing How Station WCCO Super- for_the NOR H AS TOLD BY

& Commerce Association. A brief his- tory of how the station came into exist- ence is as follows: One morning late in July, 1924, 'the Northwest awoke to discover that it was to be without broadcasting service. This condition was brought about by the clos- ing of the Twin City Station WLAG, operated by the Cutting & Washington Radio Corporation, and the closing of the Dayton Company's Station, WBAH. Everywhere discussion was rife as to what the solution of the problem should be. This condition continued until August 5, when \Vashburn Crosby Com- pany submitted a proposal to the Minnea- polis Civic & Commerce Association and the Saint Paul Association. This pro- posal was as follows: A Co- operative Plan 4SHBURN CROSBY COMPANY offered to buy the physical proper- ties of \ \'LAG and to contribute $50,000 a year towards the support of the Twin City Station for a three -year period, providing the business men of Saint Paul and Minneapolis together would con- tribute a like amount for the same period. The station was to be known as the Gold Medal Station, and was to be credited both to Saint Paul and Minnea- Opening a new broadcasting station is a rather strenuous feat. The pair above. Paul polis. \Vashburn Crosby Company also Johnson, (seated,) W'CCO's announcer, and Harry Wilburn, station manager, were offered, if their proposition was accep- fagged out after five and a half hours of steady announcing. In fact, Paul insisted that place for the microphone be brought to him. Wilburn tried to oblige. ted, to immediately an order a new 5,000 watt broadcasting equip- WCCO-a broadcasting station studios in Saint Paul. These will prob- ment to take the place of the old with a purpose -that's the Gold ably have the most unique location of equipment. Medal Station, Saint Paul -Min- any studios in the world, for they will The proposition was accepted, and on neapolis. Its purpose is to serve the North- be in Saint Paul's handsome new Union September 12 the station became a west, and twelve hours a day, seven days Depot used by nine railroads. reality. Carrying out the original agree- a week, they work at it enthusiastically. For, you must remember, the Gold ment, \Vashburn Crosby Company placed Incidentally, you have probably noted Medal Station represents both Saint Paul an order for one of the new 5,000 watt their earnest endeavors in the last week or and Minneapolis. It is not the toy of broadcasting sets, which was designed two, even if you are not a resident of any group or class, but a big service unit especially for that territory. the Northwest, for on March 4 \VCCO representing two large cities and the huge On March 4 the new broadcasting blossomed out with its new 5,000- \ \'att territory which they serve. equipment of \VCCO was formally intro- transmitting equipment, and also on that The Gold Medal Station is also unique duced to the public when it broadcast the evening inaugurated its new Minneapolis in the manner in which it is supported. inaugural ceremonies from Washington studios on top of the Nicollet Hotel. The physical properties, including the by remote control. The new transmitter is one of the super transmitting station located on the east Wednesday evening, March 4, WCCO broadcasting units, and the Minneapolis bank of the Mississippi, 18 miles north- opened its new Minneapolis studios on studios are said to be the equal both in west of Saint Paul and Minneapolis, top of the Nicollet Hotel with what was equipment and elegance of anything in the new studios on top of the Nicollet unquestionably one of the finest programs the country. Hotel, and the new studios, construction ever broadcast by a radio station. The New St. Paul Studios of which has just begun in Saint Paul, program opened at 8:00 p. m., with a are all the property of the Washburn short talk by Governor Theodore Chris- NOT satisfied with this, the manage- Crosby Company, who also operate the tianson of Minnesota, in which he out- ment of WCCO announced that station jointly with the Saint Paul lined the value of radio to the public. they would immediately begin building Association and the Minneapolis Civic The staff of the station was then intro- RADIO AGE for May, 1923 What the Broadcasters are Doing - 27 I s Keeping Up -to -Date Power Growing wvsi E. H. GAMMONS duced over the air. At 8:30 began a musical program which continued for five hours. Included on this were the leading artists, orchestras, glee clubs, and quartets of the Northwest, the band of the famous Third Infantry, oldest regi- ment in the United States Army, now stationed at Fort Snelling. Invitations were sent to approximately 5,000 residents of Twin Cities to Carlo the Fischer, attend the opening and view the broad- notedmu- casts. The result was a tremendous sictan and crowd, which jammed the hotel, ele- member of vators, hallways, and the studios them- Minneapolis. selves all evening, and gave ample evi- Symphony Orches- dence of the interest which Minneapolis tra,likes broadcasting and Saint Paul have in radio. because he can smoke his cigarette and enjoy playing. Towers 18 Miles Away THE transmitting equipment of Station aerial towers and the power house The new studios on top of the Nicollet WCCO is located 18 miles northwest Programs are received over specially Hotel are housed in a structure built of the Twin Cities on the east bank of the built telephone wires from studios in especially for them. There is a small Mississippi. There are the two 200-foot Minneapolis and Saint Paul. studio for individuals and a large studio for groups. Between them are the announcer's and operators' rooms. Glass panels in the walls of the studios make possible a view of the broadcasting by persons in the reception room and in the promenade along one side of the large studio. These studios are literally "hung in the air," the ceilings being sus- pended, the floors built upon cork, and the walls deadened by heavy drapes which are adjustable. They are luxuri- ously furnished and have been pro- nounced by those who have seen practi- cally all of the broadcasting studios as being surpassed by none. With "Service to the Northwest" as its slogan, the Gold Medal Station is now ready to provide the Northwest with programs to equal any. New Director for WCCO HENRY A. BELLOWS, well known magazine editor and musical critic of the Northwest, will become associated with WCCO soon as director, according to an announcement made by the management. Mr. Bellows in the position of director will have complete charge of the arrange- ments for and all the broadcasts from the station. He is nationally known as a writer, editor and an authority on music. For thirteen years he has been associated with the "Northwestern Miller," Minne- Visitors at the Mtnneapolis studios of WCCO on the Ntcollet Hotel may view the apolis, as managing editor, associate broadcasting through glass panels, as shown in the photograph. Roominess is one of the editor and director. Prior to that he outstanding features of this novel station. was editor of "The Bellman." 28 RADIO AGE for May, 1925 What the Broadcasters are Doing The West Proclaims a Champion Q "Uncle John" Daggett of By Harry Aldine Intensive CampaignMay KHJ, Los Angeles, is Upset Popularity Contest Winner Leaders at Any for March Moment "For East is East and West is West. your dials a twirl some night to the And Ne'er the twain shall meet." 405 meter wave and stand by to be -IVith apologies to radio. washed overboard by the joyful, "KHJ, Los Angeles, California." RADIJ, the great annihilator of distance, has reached out its THE WINNER FOR MARCH mighty arm and placed its finger John S. Daggett __Announcer._._KHJ, Los Angeles on a spot amid the orange blossoms and WINNERS OF PRECEDING MONTHS has sought out the Master of Ceremonies July -.._._..__.Duncan Sisters, KYW of the broadcasting station known as August__...__ __._..__ - Bill Hay, KFKX September.____..__.....___ Karl Bonawits, WIP KHJ, at Los Angeles. And, meeting on October....._...._ ._._._..___H. W. Arlin, KDKA November Bert Davis, WQJ common ground, the East has turned Nelson, WJJD West to proclaim a new champion in the January.- ..___._._... ___._ Art Linick, KYW person of our beloved "Uncle John" S. February_ ...... ___ ..Coon - Sanders Orchestra, KYW Daggett, the winner of RADIO AGE'S STANDING TO MARCH 15 popularity contest for the month of Name and Classification Where Heard Karl Bonawita, Organist WIP, Philadelphia March. BL Hay. Announcer .....___ _..XFKX, Hastings A newspaper man for many years, H. W. Arlin, Announcer...... ___KDKA, Pittsburgh Coon -Sanders' Nighthawks, Orchestra, KYW, Chi. Uncle John has long since learned what Harry M. Snodgrass, Entertainer_____._. constitute the fundamental elements of WOS, Jefferson City Jack Nelson, Announcer..--.WJJD, Mooseheart human interest. And by carrying his Bert Davis, Entertainer _ --.__--_ ...... WQJ Chicago unassumed geniality from the editorial John S. Daggett, Announcer---KHJ, Los Angeles Art Linick, Entertainer.._._ ...... K Chicago offices to the broadcasting studio of the Ford & Glenn, EntaYainers__...____.WLS, Chicago Los Angeles Times, he was at once Duncan Sisters, Entertainers _...KYW, Chicago Lambdin Kay, Announcer.._ -__._WSB, Atlanta accepted as one of the foremost announc- J. Remington Welsch, Organist -KYW, Cbicago ers of this country. For he is anything Fred Smith, Announcer WLW, Cincinnati E. L. Tyson, Announcer. WWJ, Detroit but supercilious. Hired Hand, Announcer WRAP, Fort Worth Step into the studio of KHJ and you Here is" Uncle John" himself, the beloved "Sen" Kaney, Announcer __..KYW, Chicago Nick B. Harris, Entertainer....KFI, Los Angeles will there find a tall man with sparkling, friend of the grownups and children at the Jerry Sullivan, Announcer -Entertainer, WQJ, Chi. kindly eyes, rumpled gray hair and a station of "Kindness, Happiness and Joys' Edward H. Smith, Director-Player...___-- where the orange blossoms come from. WGY, Schenectady winning smile. Look into his heart and Charles E. Erbstein, Announcer.._..WTAS, Elgin you will discover a fatherly personality Lee Sims, Pianist---..-'_ --._ KYW, Chicago Wendell Hall, Entertainer.._....WDAF, Kansas City that radiates through the microphone, performer is not inspiring to better things Howard Mílholland, Announcer_. KGO, Oakland bringing cheer to the sickroom, the of life and likewise educational. The Scottish Rite Orchestra KGO, Oakland Banks Kennedy, Entertainer WEBH, Chicago children, the house -wife and the busi- entertainment must be wholesome, and S. Hastings, Announcer KFI, Los Angeles ness man alike. Just such a man is above all it should appeal to the masses. Robert Borne!, Announcer_._._...WEBH, Chicago Uncle John. Religion is given its place in the Anon Trio, InsttumentaL....__..__..KGO. Oakland schedule of KHJ, and here, too, Uncle A Deadline Is Near Suitable Inspiration John has shown his keen understanding SURROUNDED as he is by singing by offering the microphone to all sects THE contest is rapidly drawing to a canaries, the studio forms a fitting and dènominations. close. At midnight, June 15, RADIO setting from which to gather inspiration In observing the spirit of close harmony AGE will accept the last of the ballots in entertaining the little folks. In this ever prevailing between the director and cast for the many favorites in the Popu- he instantly gained popular favor, par- his many artists, one at once understands larity Contest. ticularly in introducing Queen Titania, why Uncle John has little difficulty in During the period from February 16 to the golden haired tot of the "movies," securing real talent for the delight of March 15, John Daggett by virtue of and the Sandman, O. G. Pinie, her father. his many listeners. Despite his portrayal having garnered the greatest number of This trio has done much to entertain of diligence itself, he always has time for a votes through the thirty days, advanced and at the same time teach the kiddies pleasant sally or kind remark for all who his position from twelfth to eighth place. the proper way of living. come in contact with him. The studio It will also be noted that H. W. Arlin, For John Daggett believes that the houses one large "happy family." Harry Snodgrass, Jack Nelson, Fred voice of radio should do more than merely And the radio artists are not the only Smith and "Sen" Kaney have all strength- entertain. Versatile as he is dynamic, ones present. John Daggett extends the ened their positions in "Standing to he feels that the public is betrayed if a hand of cordiality to all visitors to the March 15." Charles Erbstein, Lee Sims capacity of his studio. and Arion Trio are newcomers to the Those of his vast list. POPULARITY CONTEST COUPON audience who desire Up to now, the candidates at the head Harry Aldine, Contest Editor a "close -up" of what of the list have been fairly consistent in RADIO AGE, 500 N. Dearborn St.. Chicago. happens behind the their leadership, but in spite of the short I wish to cast my vote for: scenes are assured a time that the contest has yet to run, Name of favorite.. genuine treat of true victory is by no means assured to any western hospitality. one of them. Manya race is won or lost by Classification ...... KHJ, the visitor clever jockeying near the finish. Station . Date Heard- is told, means Kind- So now for the smashing drive! Your ness, Happiness and opportunities to say it with ballots for Name loptionall_ Joy, and if you have your favorite are limited. Clip the send it in now Address (optional] not already been con- coupon and while the con- vinced, just give test is.fresh in your mind. RADIO AGE for May, 1925 What the Broadcasters are Doing 29

I

Children like to hear children broadcast. Ford and Glenn discovered that fact, and today their popularity is tremendous. Above is shown Tiny Violet Sileo lisping into the W'LS microphone for admiring youngsters. At the left, Dorothy Blackwell of WEE!, Boston, is introducing a new "pal" to the 7,000 members of the "Big Brothers'"Club.

Common Sense A New Kind Replaces Nursery of Rhyme Methods Bedtime TH E BEDTIME story is coming into its own. Not so very long ago the "queer" ladies and gentlemen who Story furnished the entertainment for the kid- dies by radio had quite a hard time get- "Uncle Bob" (Walter Wilson) of KYW, By RUSSELL H. HOPKINS ting the radio public to take them serious- who is known to millions of children who ly. In fact, they had a hard time taking listen to him every night at Bedtime Story "Uncle Bob" Wilson believes in per- themselves seriously, and as a result the Hour. sonal contact, and his immense popu- great American sport of radio bedtime larity can be largely attributed to his story- telling failed to rise above the level to 7000 child members, ranging from 1 to making periodic "personal" appearances of crude umorforseveral monthsafter the 14 years. "Bob" Emery and Dorothy in towns where his Bedtime Hours are popular advent of the broadcasting art. Blackwell are the guiding lights of this most popular. Both Wilson and KY \V The originators of the bedtime story juvenile institution, and it is through realize that this is an invaluable aid in idea thought that to amuse the kiddies their efforts that the Big Brother Club is holding the station's young friends. they had to adhere strictly to nursery today one of the strongest children's rhyme psychology. They never thought organizations in the country. ChIIdren Help, Too for a moment that maybe their childish While all this was going on in the East, FORD RUSH and Glenn Rowell, the listeners could rise above the moron plane Walter Wilson, the original bedtime story Bedtime Story Boys of \VLS, Chicago, and enjoy some real common -sense Chil- man known as "Uncle Bob" from KYW, get closest to the children's hearts by dren's Hours. Chicago, was changing his mode of "ap- introducing the policy of having children The entrance of a new form of Bedtime proach" also. do broadcasting during "Lullaby Hour" Story material occurred almost simultan- Uncle Bob had been with radio from from WLS. On certain days of the week eously in Boston and Chicago. The the start, and he had tried every known Ford and Glenn invite ambitious Lullaby owners of Station WEEI in Boston de- means of gaining the favor of the kiddies. Listeners to participate in their intimate cided to form a "Big Brother" Club along Of course, his nursery rhyme method was talks with the radio listeners, and as a the lines of the well -known organization successful, for he had the knack of con- result, thousands of children who are of that name, and to appeal to boys and veying his personality from the studio to WLS "fans" are competing among them- girls of all ages by the radio. No silly the children listening in, but like the few selves to be chosen to help "Big Ford and Bedtime Stories, mind you; no childish keen -minded radiologists of two years Little Glenn." The popularity of their prattle on how this little brown bear ago, Wilson realized the children must Lullaby Club has resulted in a tide of came home with his folks and found his have something better or they would soon correspondence that nearly equals that meal absorbed by an unknown mouth. outgrow his daily Bedtime Story Hour. received from all other programs com- The Big Brothers of radio set out to do So Uncle Bob formulated a standard bined. some real work among the children, and Children's Hour program that not only And Ford and Glenn abo..shed story- to substitute this brotherhood movement interested all children- everywhere- but telling long ago. Instead, they talk to for the meaningless kindergarten material their parents as well! His method today each other in a personal way and talk to that persisted in remaining part and consists largely of singing and playing the kiddies as if they were in the same parcel of every radio station. the piano, intermingling modernized room. children's songs with the well known 7000 Child- Members Truly, this is an era of new things in popular melodies. And this new method radio and especially in the gentle art of wEEI'S idea was an immediate suc- has been so successful that KYW's bed- winning juvenile listeners and holding cess. In a little over a year member- time story listeners have doubled during them as they grow older. ship in the Big Brother Club has jumped the past year. (Coyyriths, 1926. By Radio Ate. RIO 30 RADIO AGE for May, 1925 What the Broadcasters are Doing Some Radio Programs and Personalities Behind theScenes at KFI Where Broadcasting Is an "Art- By MARGOT LYON Program Director, KFI, Los Angeles, Cal.

THE phonograph and the camera The audience, lis- introduced the surprising fact to tening with head- many people that other people phones or with loud did not see and hear them as they saw speaker, are blind and heard themselves. The latest as far as the studio development of science in disillusioning and what is broad- some and enchanting others is the cast from the studio radio. As has been often said of other are concerned. things, you never can tell who's who Every program over the radio until you have heard must be planned them over the radio. from the start as Many of KFI's artists have sung but though it were being rarely elsewhere, some of them coming played before a to KFI with friends just to see what theater with the went on behind the scenes, and, singing lights off. Although MIIIMIIIMIIIMIIMMIKMIL just once at the request of some of the this may seem self - w regular artists, have made such a suc- evident it is not Frank Oliver, a traveling radio dramatist, is one of those rare cess that they have come again and generally con- artists who believe that they must dress and act the personality again. sidered. Every trick they seek to portray in the studio itself, if they hope to convey the is of the human voice, that same personality to listener, who can only `visualize It peculiar to witness the reaction through his ears. of those who hear singers in the studio every intonation, and then walk out to the loud speaker inflection and artic- and heár the same voice as it comes ulation must be polished to the last point Somewhat peculiar are the requests off the air. A tenor whose voice in the before the audience can attain the for songs. A singer may just have studio seems to lack resonance and maximum enjoyment from the program. finished "Pace pace mio dio" when an purity will broadcast with the utmost By letters and by broadcast requests ingratiating voice will ask, over the clarity and sweetness, his broadcast for information, KFI has made up phone of course, if the lady who just voice leaving nothing to be desired, charts of the type of program most sang could please render "Charley, My whereas a trained voice, that from the enjoyed by the public and finds that Boy." concert stage has delighted thousands, almost every kind of program has its Sometimes there is a great deal of will not "radiate" well at all. adherents. For the humorous mono- pathos in the requests. One particular logue to the classic string quartette night a frantic mother called asking It's Not a "Cinch" come letters from isolated farms and if we could not in some way help her to DUE to the difficulty in judging from yachts and country estates. Strange locate her little boy who had strayed a good radio voice and to other to say, the letter in favor of the string away. It had to be explained to her reasons not so easy to illustrate, the quartette is more than likely to come that the laws of broadcasting did not position of a program director is no from the tired wife of the farmer, who permit such announcements to be made. sinecure. However, the vast KFI audi- washes dishes or irons her clothes a Other times an old time number will be ence seems to be pleased with the sta- thousand miles away from KFI, while asked for, to please some one who is tion's efforts, to judge by the many listening to Mozart or Haydn. ill or shut in. Then the artists will letters they send. Letters come in from the blind whose scurry about and among themselves The demand of radio broadcasting only comfort is the radio and from the refresh their memories and the most has developed a supply of radio enter- deaf who perhaps have never heard a daring of them will attempt to "fake" tainers. The field of broadcast enter- sound from the great silent world until a piano accompaniment. tainment is being widened by the sincere with ear -phones they have picked up a It is not possible to grant all the re- efforts of the studio managers and the program from KFI. quests asked for during the actual artists. Phone Lines Always Busy broadcasting hour, and it is the habit As in the early days of vaudeville, of KFI at certain times to ask those the first effort toward entertainment VE of the most interesting things who wish to hear their favorites sing has been the attempt to present novelties to be met with in the broadcasting certain numbers to be sure to write in and unusual stunts. However, more station is the number of telephone their requests so that the artists may and more over the radio, as over the calls that come in during the various plan on pleasing their friends. When footlights, the combined effort of artist programs, ranging from requests for the fact is known that as many as thirty and station has developed a sincere and various numbers to inquiries as to the requests have been phoned in during worth -while form of entertainment emi- proper feeding of a baby and what are one hour for one artist, such as Starr nently fitted for the needs of radio. the ten points of a prize winning Airedale. (Continued on page 54) RADIO AGE for May, 192 The Magazine of the Hour 31

A Compact Traveling Set The 6 -Tube "Portatron" By JOHN B. RATHBUN

COMPACT portable radio receivers Çopyright: 1925 ling requires no separate interstage con- having sufficient power to operate trols, but unfortunately, resistance coup- on either loop or fiat top aerial, are Controls are Simple ling in the radio frequency stages is only desirable for home use as well as for efficient on long wavelengths, say on camping and motoring trips. Provided and Operation Quiet wavelengths above 1,000 meters. This with self- contained batteries, such outfits resistance coupling method will be fine can be easily moved about from room to and this system must therefore be dis- for the audio stages, and is just What will room in the house or came carried to the carded right at this point, both for the be used for the output, but we will have home of a friend to provide music for a reason that it takes up much room, and to guess again in regard to the coupling on dance or for other similar occasions.'The also for the reason that a separate dial the R. F. end of the hookup. The portable has a much wider field of appli- control will be required for each radio untuned or fixed radio frequency trans- cation than the conventional, cumber- stage (and for the tuner unit in addition) former at once suggests itself, but for this some cabinet with external batteries, and which will bring number of time it must be rejected because of the should the total be seriously considered by those controls up to three or more. This is out. space occupied and for the reason that who desire a of all -round type. such - receiver the of the question in a portable outfit; hence transformers are likely to "back sake such For the of simplicity, an we must look farther for a means of radio couple" between stages if crowded to outfit should be of the single control type, frequency stage coupling. We should gether as closely as we intend to crowd the or should not have more than two controls have only a single selective control for the stages of this outfit. at the most. It should have at least two tuner unit, and no variable controls after radio frequency stages for distance and the first stage that are represented by THEREs only one other coupling pos- for operation on a loop aerial, and at dials or knobs on the front of the panel. sible on the R. F. end, and that is least two audio frequency stages for loud by means of inductances of the "choke speaker operation.. With transformer Resistance Coupling coil" order, which are connected into cir- coupling this means at least five tubes, Resistance coupling for the radio cuit just like the resistance units of a if the tubes are not reflexed, and we must requency and audio frequency coup resistance coupled stages. One end of therefore carefully consider the methods the choke coil is connected to the plate of of coupling the stages to conserve space the tube, while the other end goes to the and to minimize the number of controls. THE RECEIVER FOR ( +B). The connection between the Dry batteries must be used for the fila- YOUR NEEDS first tube plate and the grid of the follow- ment "A" battery, and the type of tube This Summer's tendency will be ing tube is made through a fixed condenser must be such that not more than three for simplified radio receivers, with just as in the case of the resistance or four No. 6 dry cells will be required. compact parts and ease of operat- coupling scheme. The choke coils must This, of course, suggests the "199" tube, tion and control. A radio, set have a very much higher inductance than which is ideal for a portable rig because of without these characteristics can- commonly used with radio frequency its low filament current consumption.and not be called up-to -date. tuning units. They should consist of small size. Five "199" tubes will take THE RADIO AGE ANNUAL for several thousand turns of very fine wire. 1925 contains several of these won- 5 x 0.06 =0.30 ampere which is not pro- der hookups that are easy to build, The secondary coil of an audio frequency hibitive for dry cell service, and the cells easy to operate and pleasant to transformer will be just about right for will last for a considerable length of time hear. The latest in portable sets as this purpose when standard 100 Milli- on such work. Six tubes will take: 6x0.06 well as the larger models are all in henry chokes cannot be obtained. The =0.36 ampere which is within reason. this new ANNUAL, which is yours inductive value must be sufficient to choke Transformer coupling between either for $1. Send your remittance now back the high frequency plate current so the radio frequency or audio frequency if you want to have this radio that it will not short circuit back through If handbook with you on your vaca- the "B" battery connections, stages takes up considerable room. tion this year as an ever -ready and at the the R. F. transformers are of the "tuned" radio guide. same time the coil resistance should not type then they must be spaced well apart $1 while they last. be sufficient to interfere with the supply to prevent coupling back between stages (Turn to page 34) Blueprints of the Six -Tube "Portatron" on Two Pages Following

o .0

yfre 0.0

IW

00 e 1,111 1

._. u) o a t V d% o. 11!/f - a

0 Y-- _ ob Ó e e -- á--tQIQD

a MS JN 11110101111

111 z z t.9 2i11d9 b;, 817IOng; i"41ß11d9 31d1d S110/1 06

1

O!

s.!;:.,

4

%='=I=Iiii ;,

1aeuuv®IlncamuL

1NI11111111IIIL,,:I' Mir

;y .SEEM

IIIIII111®_i711Ì1111lIIIN :°;

4 ail or-7. 34 RADIO AGE for May, 1925 The Magazine of the Hour (Continued from page 31) to 135 volts of "B" battery will be main- tubes and increases their effectiveness. of continuous "B" battery current to the tained on the plate. The plate of tube At tube (T3) we have the detector tube plate of the tube. The choke coil permits (T1) is coupled to the grid of the second which is connected into circuit by the the "B" battery current to pass to the R. F. tube (T2) through the fixed coup- 0.00025 mf. fixed grid condenser (K2), and plate, but chokes back the R. F. current. ling condenser (K1) which is ordinarily the one megohm grid leak (GL1). As with of 0.002 mí. capacity. This condenser all the other tubes, this is a "199" tube, Radio Frequency Amplification prevents the application of the plate but to prevent critical rheostat adjust- rrHE application of the choke system voltage to the grid of (T2) and thus pre- ments the plate is supplied with 45 volts .L to the first three tubes will be seen vents the high "B" voltage from paralyz- by an intermediate tap at the "B" bat- ing this tube. The choke coil (CC) can tery. From in Fig. 1 and Fig. 2, where Fig. 1 is a the detector tube on, all of the schematic diagram using symbols, and be the secondary winding of an audio stages are resistance coupled by the Fig. 2 is a picture wiring diagram. The transformer, and as will be seen, prevents 50,000 ohm resistances (M1- M2 -M3) and first will be of more service to the experi- the R. F. plate output from short circuit- the grid leaks (GL2 -GL3 -GL4). The enced builder in "doping out" the circuit, hand controlled rheostat is shown at (R) while the latter will show the novice how by which the detector filament can be the wiring connections are actually made YOU PORTABLE FANS! controlled accurately for any conditions. to the parts. Fig. 3 is a front elevation For use with "199" tubes, the resistance If you want a smaller and even (R) of the panel and cabinet, while Fig. 4 is a more compact portable receiver of should be from 30 to 40 ohms, the rear elevation showing the parts assem- than is described in the RADIO former for dry cell operation and the bled at the rear of the panel. Fig. 3A is AGE Blueprint section this latter for use with storage cells. a sectional view as seen from one side of month, you'll find another in the JUNE ISSUE, out May 15. Resistance Coupled Audio the assemblage. It will be Taking Figs. 1 -2, we seè that an aperi- ALL of the three audio frequency tubes odic type coupler is used at (LI -L2) A 3 -TUBE PORTABLE (T4- T5 -T6) are supplied with the which is tuned by vernier variable con- REFLEX full "B" battery voltage through the denser (Cl) connected across the second- "THE BABY OF THEM fixed resistances (M1- Al2 -M3) which have ary coil (L2) of the coupler. This can be ALL." a resistance of 50,000 ohms. The plates a home -made coupler such as has been Just the thing to put in your and grids of the tubes are connected by described many times in these columns; suitcase for that vacation trip. means of the fixed condensers (K3 -K4- it can be a standard neutrodyne trans- By John B. Rathbun K5) of 0.005 mf. capacity. This value former or else a standard adjustable is not critical, and 0.006 mf. fixed con- aperiodic tuner. In any event, the IN JUNE RADIO AGE densers can also be used if this is the only primary coil, (LI) is untuned. When the capacity to be found in stock at your usual flat top aerial is used, the aerial radio store. They must be of the mica lead -in wire is connected to (ANT) and ing through the "B" battery. It allows dielectric type, or condensers in which the the ground wire at (GND), a system whch the "B" battery to go to the plate of the plates are separated by thin sheets of gives the greatest range and signal first tube, however, but stops the high mica insulation. strength. By connecting the ends of a frequency current from backing out. The grid leaks (GL2, GL3, GL4) loop aerial at (XI) and (GN D), and then This requires no control. of the audio tubes "taper" toward the opening the grid. switch (T), we can oper- rear; that is, the last tube has a higher ate on the loop aerial. The tap switch Filament Controls leak resistance than that of the first (T) cuts out the secondary coil (L2) ALL of the amplifying tubes, five in audio amplifying tube. (GL2) =1.0 which is necessary on loop reception. number, are provided with auto- megohm, (GL3) =5.00 megohm, and Coil (L3) suppresses oscilations. matic filament controls which maintain (GL4) =25.00 megohm. This arrange- When operating on the flat top aerial, the amplifying tube current at the proper ment gives a stronger bias to the grids or a type similar to the usual outdoor intensity without rheostats or other on the tubes which are most heavily aerial, the coupling between the primary manual controls. This is a decided step loaded, and therefore results in a better (L1) and the secondary (L2) must be very toward simplicity and compactness, and distribution of amplification through the "loose;" that is, there must be a consider- prolongs the life of thetubes byholdingthe three stages. The output of the sixth able space between the two coils. For this filaments constantly at the proper temper- tube (T6) leads to the output jack (J1). reason, it is best to adopt a ready -made ature. A manual rheostat (R) of the A full 90 volts must be maintained on coupler in which the coupling gap can be usual form must be provided for the the plates of all amplifier tubes, and where easily adjusted until the proper degree is detector tube (T3) as this has a rather possible, this should be increased to 112.5 found by experiment. We have only one critical filament adjustment that cannot volts as the choke and resistance coupling control, and to obtain the proper selec- be automically controlled. The rheostat demands a higher voltage than the straight tivity in local jams we must have the (R) is represented on the front of the panel transformer coupling ordinarily used. proper "looseness" between the coils. The by a knob as shown by Fig. 3, and is the Two vertical type 45 volt blocks will home -made coil generally contains from only control outside of the condenser dial take up the minimum amount of space 12 to 15 turns of No. 26 D. S. C. wire on (C1). A switch (SW) must be provided for in the cabinet when the batteries are the primary (L1), and from 55 to 60 turns shutting off the filament current when the carried in the cabinet, but a third small on the secondary coil (L2), using the same set is not in use. It is no longer possible to 22.5 volt block will greatly improve the size wire. The distance between the two turn off the amplifying tubes indepen- performance by raising the voltage to coils, or the coupling, may be from 34 to dently as when the usual form of rheostat 112.5 volts. The great trouble with a ?4 inch or even greater. is used. This can be an ordinary battery portable set is to get the batteries into By using a 4.5 volt three cell "C" bat- switch of the type to be found at any place without monopolizing all of the tery at (C), we usually get greater sensi- radio store. cabinet space. When the set is built for tivity and signal strength, and the battery A second choke coil (CC) is shown con- ordinary stationary service, then we can also reduces the tendency towards free nected to the plate circuit of the second use three 45 volt blocks of "B" battery, oscillations in the circuit. However, the radio tube (T2), and as this is exactly giving 135 volts, and will thus obtain "C" battery can be omitted in many similar to the first, there will be no further the maximum output of the tubes. The cases without serious loss. The switch comment. The output of tube (T2) leads small size "B" batteries must be used (T) can be the usual form of tap switch to the detector tube through the 0.00025 for the portable set. with one active contact point, and one mf. grid condenser (K2). It should be Filament or "A" batteries are to be dead contact. noted that a one megohm grid leak (V), No. 6 cells and are connected up in series The first radio frequency tube (T1), shown dotted on the grid of tube (T2), to give a total of 4.5 volts across the which follows the tuning inductance, is will often prove of advantage. It should at rheostat. When possible, these should provided with the choke coil (CC) con- least be tried out in the position indicated be square batteries so that the maximum nected to the plate at one end and to the by the dotted lines before completing the amount of battery material can be put ( +B) line at the other, so that from 90 set, for it sometimes stabilizes the first into a minimum of space. The demand RADIO AGE for May, 1925 The Magazine of the Hour 35 of the six tubes is slightly greater than THE finish of the cabinet depends bakelite panels should not be less than that ordinarily recommended for con- upon the taste and ingenuity of the 3 -16 inch and this also covers the shelves tinuous service (0.36 ampere), but builder. It can be polished with wax or which should be of the same material with careful handling they can be made varnished in natural wood finish, or as the panels; that is, hard rubber, bake- to last for a long time before replacement it can be covered with leatherette or lite or formica. The shelves carry the becomes necessary. similar black grained covering material. wiring and many of the current carrying If leatherette is used, then all of the parts so that their insulating value should Reason for Six Tubes corners must be well rounded off so that be fully equal to that of the panels. `1(TITH transformer coupling on both the material will not get loose or buckle We cannot go further into the details V V radio frequency and audio frequency along the edges. The front face of the of the cabinet construction, but the con- stages, a five tube set is commonly built battery compartment door comes flush struction will be clearly seen by those with two radio stages, detector, and two with the face of the cabinet and who are competent to undertake work audio stages. With choke coils in the panel door; hence this part is given the of this sort, and if one is not sure of being radio stages and resistance coupling in same finish as the outside of the cabinet. able to build this cabinet, the drawings the audio stages, the amplifying power Rubber pads or feet (i) prevent the set are amply dimensioned for a practical of the tubes is somewhat reduced so cabinet maker. If you give the job to that one more tube will be required to BILL OF MATERIALS USED a cabinet maker, I suggest that you also give thé same results. However, this is The following list will give the materials used and their give him the panels and shelves so that parts listed refer- he can get a good fit betwen the edges more than compensated for by the sim- ence letter, sed on the Imo that h their relation plicity of the controls and the clear 'can he seen at a glance. of the panel and the rabbet of the cabinet. toned, noiseless operation of the set. PORTABLE RECEIVER MATERIALS "A "-3 Filament "A" Dry Batteries. 1.5 volt, o. 6. Arrangement of Apparatus It has a far better tone than with the ANT -1 Loop aerial (optional), 2 Ft. Square. "B " -2 "B" Plate Batteries, Vertical type, 45 Prit usual arrangements and can be handled "C"-1 "C" Bias Battery, Three cell. small, 4.5 volts FIG. 4 shows the arrangement of the C1-1 Vernier Variable Condenser (23 plate`. 0.0005 ml seen by the rawest novice in radio. CC-2 100 Millihenry Choke coils, or audio trans- apparatus as from the rear of the 3, showing the front elevation of former secondary coils. panel. The six tube sockets (U) are Fig. D -1 Special cabinet, as specified in drawings the panel and cabinet, gives a good idea E-i Special Panel, as specifiedin drawings, 3/16 -inch placed in groups of three on the two Bakelite. of the general arrangement of the F -H -2 Special elves, as specified in drawings, 3 -16 shelves (F) and (H), and the outlines of inch Bakelite 5.x6 receiver when designed as a portable set. G-1 Carrying a ngle Complete. Standard. the tubes are indicated by thin dot and GL1-1 Grid Leak, 1.00 Megohm. dash lines so that the allowance The cabinet is really divided into two GL2 -1 Grid Irak, I.0D MKhom, for shelf (1) the upper portion covered by GL3-IOrid Leak, 3.00 Megohm. clearance can be easily seen. The tubes parts, GL4-1 Grid Leak, 25.00 111egohp,. the panel being for the radio circuit h-4 Hinges or hints, Standard. are numbered so that their relation to 1 -2 Lock Catch, Standard. proper while (2) the lower compartment I-4 Ruhher pads or feet, Medium Sire. the circuit drawings of Figs. 1 and 2 can J1-1 Single Circuit Jack, Standard. houses the "A" and "B" batteries. As TI-1 Fined Condenser. Mica dielectric. 0.002 mf. be easily followed, and the sockets can K2 -1 Fixed Co denser, Mica dielectric. Grid clips. be located in the saine this is a special arrangement, the cabinet 0.00025 mt. way. Fig. 3A will have to be made specially K3 -1 Fixed Condenser, Mica dielecrie, 0.005 or and Fig. 4 can be used in combination, and panel 0.006 mt. for the job and it is not likely that a ready - K4 -1 Fixed Condenser, Mica dielectric, C.005 or thus obtaining the side and rear eleva- 0.006 mt. made cabinet or panel can be found which K5-1 Fixed Condenser, Mica dielectric. 0.005 or tions of the assembly. 0.006 tat. will exactly fit the conditions. L-4 Brass Angle Brackets, Standard. It will be seen that the shelves are cut of Fig. 3 we see Ll -L2-1 Aperiodic Try. Couple -. Standard. off at the right in Fig. 4 to accommodate In the front view that Ml- M2.313 -- 350,000 ohm Resistor Units, the panel contains all of the controls, R -1 Filament Rheostat. 30-10 ohms. the variable tuning condenser (C1) and d -r2, etc. -5 Automatic File. Controls Amperitesl and also the three binding posts for the 199-4.5 colts. the tuning inductance (Li -L2). On SW -1 Battery Switch, Standard. aerial (ANT- X1-GND). The dial of the T -1 Tap Switch, Standard. the lower sides of the shelves will be seen t -2 Contact points, with two stops, Standard. the coupling resistances, tuning condenser is at (Cl), and for Tl -T2, etc. -6 Tubes, "199.' grid condenser, be a four -inch dial V-6 Ahsorher Base Tuhe Sockets. "199" Type. gridleaks and the wiring. In making accuracy this should 40° Tinned Square Copper Bus Wire, So. 14. with some sort of vernier arrangement, 75 Solder Clips, Tinned. Standard. allowance for the space between shelves, S Binding Posts. Composition Caps. Standard. as the tuning is exceedingly sharp. 2-1 Brass angle connections. Standard. measure the height of the tube plus the V -1 Leak, 1 megohm. The rheostat control (R) for the detector VM- Filament voltmeter. 0.8 volts. height of the socket, plus a little more tube is at the right of the condenser dial. clearance so that the tubes can be taken The battery switch for turning the "A" out of the sockets and replaced without battery current on and off is at "SW" from scratching finished surfaces on which tearing the set to pieces. In other words, and the output jack is (J1). In the it may be placed, and further, they the true height of the socket assembly upper right hand corner of the panel is prevent or help to prevent, the ringing is the sum of the tube height, plus the the grid switch (T) by which the set mlcrophonic noises experienced with socket height, plus inch clearance can be thrown over from flat top aerial "199" tubes. between the lower end of the tube and to loop operation. This is all there is Shelf for Tubes the top of the socket. to the control of the set and its external The side sectional view of Fig. 3A shows The arrangement of the battery com- connections. that a shelf (F) is used for carrying the partment in general with the batteries As will be seen from the side sectional first three tubes, and that this shelf is in place is marked. Strong flat springs view, Fig. 3A, the panel is set back from attached to the panel (E) by means of made from flat spring brass plates bear the front edge of the cabinet so that the brass angle brackets (L). The shelf (F) on one side of the batteries and hold them front door will clear the knobs and dials. carries the first two tubes (T1 -T2) of in place against jolts and jars when the The door swings on two hinges (h) and the radio frequency circuit and also the set is being carried. Connections between is just large enough to cover the panel, detector tube (T3). Below the upper the apparatus and batteries are made by the top of the battery compartment shelf is the lower shelf (H) which carries. means of flexible fixture wire which can being at the lower edge of the door. the three audio tubes (T4- TS -T6). As be obtained from any electrical store. Any suitable catch or lock (I) can be the resistance units and other parts of This is very flexible and well insulated, used on the left hand edge of the the circuit are carried on the underside and makes an ideal connection. The ends cabinet for fastening the door, and a of the shelves with the sockets on top, of the fixture wire should be provided lock is not a bad idea even in the home, we must be sure to leave room to accom- with "spade" type tips soldered to the as it prevents children from tampering modate the height of the tubes over copper strands, and these make a perman- with the set. At the top is a leather their sockets, plus the thickness or height ent contact with the connection screws handle (G) fastened to the cabinet by of the resistance units and the condensers, which is easily attached and which does standard hardware that can easily be plus clearance. not loosen under ordinary conditions. obtained from a trunk or suitcase house The material used for the cabinet can Do not attempt placing the strands of or from some hardware stores. The lower be 5 -16 inch or 3 -8 inch thick, but if care- wire directly under the binding screws. battery compartment door, just below the fully constructed with dovetailed or for when connected up in this way they panel, is shown closed. It is through this matched corners, will be perfectly safe are almost certain to get undone. opening that we replace the batteries. when built of 5 -16 inch stock. The (Turn to page 38) Blueprints of the Six-Tube "Portatron" on Two Pages Following 111111411 11 iiiii

'11I§§l11/

¥YR ¥s a2Ç c..7A9/0 r ,46E; /N& c/C,460.. 7

s

o

- v./T /\./ '` ; ''.F

2 10Y111 III 11111111111U IIII,Ih¡N III 110IIIII II

Hc >, I

b

6b

.:00 I h II,IIIIIIIINIIIq u 111111 r1111 38 RADIO AGE for May, 1925 The Magazine of the Hour Economy of Arrangement Is Vital (Continued from page 35) the divisions are the largest, and the In the center, and at the bottom of Alternative Arrangement battery voltage should not throw the Fig. 1, will be found a detail of a small needle to the far end of the scale. radio frequency choke coil which can AS WILL be seen, the part of the Suppressing Oscillations be used when an audio frequency trans- assembly taken up by the receiver former secondary is not available. This proper is very small, the panel measuring Free oscillations in the radio fre- consists of about 450 turns of No. 36 10% long and 1134 deep, but for some quency stages are the greatest difficulty D. S. C. wire wound on a cardboard purposes the total height with the in the construction of a radio frequency or bakelite tube as shown, and is mounted batteries included may be too great to or reflex type of receiver, and we must on the upper shelf (F) of the set. Some be practicable. In such a case, the devise some system for stopping these little experimenting may be required battery compartment can be made oscillations if we expect to get the full to get the most effective number of separate, terminating the receiver por- output of the set. In fact, most of the turns, but the coil is not very critical tion at the board shown running over trouble reported with sets having radio to the turns, and for most apparatus the the tops of the batteries. This, however, frequency stages can be traced to im- number of turns shown will come very makes it necessary to reconnect the bat - proper or imperfect methods of damping close to the best effect. We must have teriesevery time that the receiveris set up down the oscillations. There are a enough turns so that the tubes will not and as a result it is a decided nuisance. number of methods of stopping oscilla- paralyze on the higher wavelengths As laid out in the drawings, there is tions, among which are the potentio- through leakage of the R. F. current ample room for a fifth "B" battery if meter, neutralizing condensers, bias bat to the "B" battery. it is desired to operate with a plate teries, etc., but in this receiver we have sim In the lower right hand corner of voltage of 11234 volts, or a sixth "B" plified the problem by the use of a plate re Fig. 1 is a detail of the resistor assembly battery if we wish to operate at 135 actacne coil marked (L3) on the diagrams. used in the audio frequency stages. volts. Further, there is room for one Coil (L3) consists of four or five turns \Ve can assemble the resistors and grid spare "A" battery if it is desired to carry of wire wound on the end of the tuning leaks on the shelves by means of clips this replacement along on a trip. coil. One end of this coil is connected as shown, or better yet, we can buy The voltmeter (VM) is a very desir- to the plate of the first radio tube as these completely assembled units from able instrument, particularly when dry shown, while the other end is left opened our advertisers, at a reasonable figure. cell "A" batteries are used, for it at or is unconnected. As one end is opened, once indicates the drop in voltage due only capacitative current will flow from Summary to weakening batteries. Unless we have the plate into the coil, and the magnetic IN tuning this set, the adjustment of some means of testing the voltage coupling is therefore very feeble, as it the detector rheostat (R) is of great occasionally, we are likely to believe should be. Some little experimenting importance, for there is one position that the set is out of order when the will be required in adjusting this coil of the rheostat where the detector tube voltage drops, and waste much time before it just stops the oscillations. is the most sensitive and gives the chasing for trouble in the wiring when It may be that the plate connection greatest volume. This generally occurs the difficulty actually exists in the must be connected to the other end of when the rheostat is about one-half on, cells. Just because automatic filament (L3), or that the whole coil must be and it is seldom necessary to turn on controls are installed for the regulation wrapped on the other end of the tube. this tube to full brilliance as with the amplifier tubes. of the filament current is no reason Varying the number of turns, or the why the voltmeter should be omitted. distance of (L3) from (L2) may be In giving his Five Tube Radio Fre- Voltmeters must be connected properly required. Just because you have not quency Receiver in the April issue the according to polarity, and you must hit the proper combination on the first name, "Amplex Receiver," our blue print be guided by the markings on the instru- trial is no proof that it will not work. editor inadvertently used the trade -name ment. If the polarity is wrong, then The losses are at a minimum with this of a receiver manufactured by the Amplex the needle indicator will be thrown arrangement, and there are no separate Instrument Laboratories of New York against the wrong end of the scale. controls as when a potentiometer is used. City. RADIO AGE wishes to inform its size of the voltmeter should be so In addition to the compensating coil readers that the set described in the blue- The 1 chosen that the full voltage will bring (L3), the "C" battery will be an aid in print section of April issue was in no way the needle near or slightly beyond the keeping down oscillations and increasing related to the receiver made by the center of the graduated scale where the sensitivity of the first two tubes. Amplex concern. End your Radio Troubles for 30e in Stamps We have laid aside a limited number of back issues RADIO AGE for your use. Below are listed hookups to be found in these issues. Select the ones you want and enclose 30e in stamps for each desired. The supply is limited. so enrich your store of radio knowledge by laying in an ample stock of copies NOW! 1924 July, 1924 December, 1924 January. New 8 -Tube Super -Heterodyne. uning Out Interference--Wave Traps-Eliminators -A Portable Tuned Impedance Reflex. -Blueprints of a -T -Operating Detector Tube by Grid Bias. -How to Slake a Receiver that Siinimixes Static. -Filters. Three -Tube wizard Circuit. Tram- Atlantic DX Receiver. Junior -Heterodyn . -A -A -A Super Make a Home Stade Charger and -Push -Pull Amplifier. -Data Sheets. -How to Battery Loud Circuit. Auguet. 1924 Speaker at a Small Coot. -Rosenbloom -Breaking Into Radio Without a Diagram. January, 1925 March, 1924 -The English 4-Element Tube. -A Refiexed Neutrodyne -An Fight -Tuhe Super -Heterodyne. -Filtered Heterodyne Audio Stages. -A Six Tube Super-Het. -A simple, low lane tune. -.An Audio Amplifier Without an "A" Battery. -An Efficient Portable Set. -A Tuned Radio Frequenrs Amplifier -Data Sheets. -A Tuned Plate Regenerator. -8itup.e Reflex Set. September. 1924 -Molina a Stetion-Fioder.J., April, 1924 -How Careful Mounting Will Improve Reception. February, 1925 Efficient Super-Heterodyne (fully illustrated,. -One Tuning Control for Hair's Breadth Selectivity. -A Sure Shot Super-Het. -A -Four Pages of Real Blueprints of a New Baby Heterodyne -A Three Circuit Regenerator. -Anti-Body Capacity Hookum. and an Aperiodic Variometer Set. -A Real. I.ow Loss Set. -Reaming the Three-Circuit Tuner. -Data /Siesta. -Blueprints of a 3 -tube Reflex. -Index and fins two installments of Radio Age Data Sheet.. October. 1924 March, 1925 -An Easily Made Super -Het. -A Permanent Super-Het. May, 1924 -Two Radio and Two Audio for Clear Tone. -A 5-Tube R. F. Receiver. -Construction of a Simple Portable Set. -A Simple Regenerative Set. -How to Wind Low Lou. Coils. -Radio Panels. -The Ultrudyne for Real DX. -A Short Wave Receiver -Third Installment of Radio Age Data Sheets. -Real Blueprints of a 3 -Tube Neutrodyne an a Midget -Blue Prints of a Two-Tube Ultra Audion and Res June. 1924 Reflex Bet. generative Reflex. -Important Factors in Constructing a Super- Heterodyne. November, 1924 April, 1925 -A Universal Amplifier. -Blueprints of a Single Tebe Loop Bet and Capacity -A 3 -Tube Postahle Bet -A Sure Fire Reflex Set. Feedback Receiver. -'A" Voltage from the A. C. Socket -Adding Radio and Audio to Baby Heterodyne. -A 3-Tube Low Lose Regenerator. -An Amplifier for the 3- Circuit Tuner -Radio Age Data Sheets. -Mastering the 3- Circuit Tuner. -Blueprints of a Five-Tube Radio Frenuency Receiver RADIO AGE, Inc. 500 N. Dearborn Ste, Chicago RADIO AGE for May, 1925 The Magazine of the Hod, t DEVICES Radio Age Institute displaying this seal have been tested Manufacturers' Testing Service and approved by BERS of the stastaff of RADIO AGE will be pleased to test devices the RADIO AGE MEMand materials for radid manufacturers with the object of deter- INSTITUTE. mining their efficiency and worth. All apparatus which meets with the approval of various tests imposed by members of the technical staff of RADIO AGE will be awarded our endorsement, and the seal Apparatus illus- shown to the right will be furnished free of charge. Materials for trated and des- testing should be sent to cribed below has successfully passed RADIO AGE INSTITUTE our tests for May, 504 N. Dearborn Street, Chicago, Ill. 1925.

Test No. 47. THE QU.A_M CONDENSER. Sub- than any other crystal. When tested for selectivity, Test No. 55. The GLOBE HEADSET. Manu mitted by the Quam Radio Corporation, of Chicago. tuning was so sharpened that interference was cut to factured and submitted by the Globe Phone Manu- III. The manufac- a minimum. While other crystals burned out by the facturing_ turers claim this con- application of repeatedly strong signals, the Car - of Reading, denser to be the borundum detector stood up well for the period in Mass. The Globe lowest loss commer- which it was used. The detector comes marked so headset was test- cial condenser made. that in a single circuit crystal set one end. marked ed both on local The radio frequency "A" is connected to the aerial, and the end marked and distant. sta- measurements taken "G" goes to the ground. For other sets, the "A" end tions in Chicago of this condenser in connects directly to the grid connection on the and in every in- our laboratories in- secondary of the radio transformer or coupling coil. f. stance clarity of dicated they are and the G" end goes to the phones or to the plate tone as well as a not exaggerating_ in connection on the primary of the audio transformer surprising "sweet- their claims. This Sat sfactorily passed the tests and requirements of ness" on high condenser has a resist- RADIO AGE Institute. notes was evi- ance at least as low dent. These re- as the standard to Ti Test No. 51. NA -ALD SOCKETS. Manufac- ceivers are super- which it was compared, for the whole broadcast cured and submitted by the Alden Manufacturing sensitive. furnish- frequency range and for various values of capacity. Co. of Springfield, Mass. ed with brass The very low losses are attributed to the high leak- These sockets are made of cases, high po-. age resistance and low dielectric losses, due to the use high grade moulded Bakelite Iish nickel finish. of the pyrex end plate, which is well out of the dense by a special process. Ac- ore winding is part of the field. Arrived in good condition and cordingly the losses were shielded, magnets are of drop forged steel, rust proof satisfactorily passed the tests and requirements of very low. The finish on and terminals are concealed. The adjustment on the RADIO AGE Institute. these sockets is permanent head is comfortable. Tests for volume also produced and stood up well over remarkable results. Satisfactorily passed the tests and Test No. 48. The ULTRA VERNIER Tuning extensive use. Na -A Id sock- requirements of the RADIO AGE Institute. Control. Submitted by the Phenix Radio Corpora- ets are guaranteed indefi- tion of 3 -9 nitely. Satisfactorily passed Test No 56 The TRI JACK and B M S Jack nlut:i udhioip Bee the tests and requirements Submitted by the Brooklyn Metal Stamping Co. of Street. of the RADIO AGE Institute. 718 Atlantic Ave , Brook- . lyn, N. Y. The Tri Jack, \`t . e York Test No. 52. CRESCENT LAVITE RESIS- shown in the illustration. '\ + C i t y. TANCES. Manufactured and submitted by the was found to eliminate This tun- Crescent Radio Sup - capacity effects almost / ing con- ply Co. of 9 Liberty entirely. It is a single 3 $ trot) was St. ,Jamaica, N. Y. circuit and double circuit ` designed These resistances jack combined and the ;i a+ by the when used in place of very latest in radio de- w e I I- iron core transformers velopment. It is one- known in audio amplification, were found to positively third the size of the ordi- radio e n- eliminate distortion. Besides giving pure tone quality, nary jack. It is made of gineer. they reduce B battery consumption and make a C moulded, solid Bakelite R. E. La- battery practically unnecessary in most cases They and the overall dimen- cault. and were mounted in our tests under an ordinary gang sions are one inch by one it is socket. Satisfactorily passed the tests and require- inch.- The terminals are geared ments of the RADIO AGE Institute. clearly marked. The B. I o w M. S. Jack. submitted enough to Test No. 53. NA -ALD SUPER DELUXE DIAL. with the Tri-Jack for test, give hair- Submitted by the Alden Manufacturing Company was also found efficient splitting accuracy without making tuning tiresome. of ring - for single open circuit It is geared 20 to I. The face,,ot the dial remains fid lass. work. It is designed for easy soldering. Lugs are rigid on the panel. The rotor or moving arm turns Dial No. spaced to be always accesssible. The lug tips are from the vernier knob at the bottom of the dial. 3044 for cupped. Satsfactorily assed the tests and require- The real usefulness of this dial in quick and accu- l-4 inch molts of RADIO AGED Institute. rate tuning is the provision made for the fan CO in- shaft was dicate on the dial with pencil or ink the station he tested in Test No. 57. desires. These units are very attractive in appear- several AMPERITE. ance. tests and require- RADIO Manufactured by ments RADIO Institute. the Radial) Co. 50 hookups Street. No. 49. DUPLEX MATCHED CONDEN- Franklin Test and and found NewYork,N.Y. An SERS. Submitted by the Duplex Condenser efficient automatic resist- Radio Corporation of and at- ance used in place of the customary rheostat. The 42 Flatbush Ave., r- tractive small tube that contains this resistance element is Brooklyn,N.Y.These besides equipped with two metal ends which are used as condensers come in being economical in price It was found that gradua- terminals when it is inserted in the base supplied sets of three, and their tions in these dials have been carefully designed to with the instrument. Being automatic in action and advantage lies in sim- make positive and rapid tuning possible. They are needing no adjustment, it will be found very useful plified logging, for made of genuine Bakelite with brass bushing. Satis- for controllin the filament temperature on ampli- their use affords uni- factorily assed the tests and requirements of the fying tubes Tested and approved by RADIO AGE form dial settings for AGE Institute. Institute. neutrodyne and all RADIO other tuned r. f. re- Test No. 54. THE HANDY CONDENSER ceivers. Tests proved CLIP. Manufactured and submitted by the Ridge Test No. 58. THE CUT- that Duplex conden- LER- HAMMER TOGGLE sers are accurately Manufacturing not Company of 3818 - SWITCH. The Cutler -Ham- made and do N. Ridgeway Ave., mer Manufacturing Com- change capacity un- Ill. This a pany have recently added o less varied by the Chicago. t N clip was designed - their line of radio products a operator. Rotor plates of ' new Toggle Battery Switch. I t for the purpose are die -cast in their ..- giving greater care has large wipe contacts, posi- shaft and stator to fixed condensers tive make -and-break mech- plates are forced into wide- spaced terminals the end posts. The con- in radio receivers. anism, undersize slots milled in This clip. for use and attractive appearance. denser submitted was a 21 plate. Satisfactorily is as to embody of the RADIO with fixed condens- It so designed passed the tests and requirements ers. was tested over the best features of its type AGE Institute. a period of thirty and also to eliminate every days and it was disadvantage. The mechanism is enclosed in a dust found that signal proof cover and the metal parts are attractively strength was con- finished in polished nickel. The switch is easily siderably augment- mounted on any radio panel in a few minutes, and ed. It is useful for does not require any screws or measurements. A preventing t h e lock nut is provided for proper adjustment for panel Test No. 50. the CARBORLMDLM CRYSTAL change of capacity thickness. When installed, a flip of the operating DETECTOR. Submitted by the Carborundum in the fixed condenser. shorting the circuit or opening lever with the finger turns the current "on' or "of. Company, Niagara Falls, N. Y. This detector con- the circuit, and otherwise generally protecting the An easy and convenient type of switch to operate. tains a special carborundum made for radio purposes. condenser from outside damage. Satisfactorily Manufactured by the Cutler- Hammer Manufacturing Tests in our laboratory revealed that this detector passed the tests and requirements of the RADIO Co., Milwaukee, Wis. Satisfactorily passed the gives volume equal to any and in many cases more AGE Institute. tests and requirements of RADIO AGE Institute. 40 RADIO AGE for May, 1925 What the Broadcasters are Doing World's Smallest Studio Now on the Air Gay Artists Perform from WJJD's Burlap Studio

Radio listeners cannot enjoy Flo Henry's entertainers, (and some of them have Lillian Bernard is an expert at character bewitching gaze, as shown above, but been there as long as two years), Lillian songs and popular renditions. She has they can hear her equally bewitching voice Bernard, Flo Henry, Frank Mason, Jack been a favorite among Chicago cafe fans from WJJD's burlap studio at the Ren- O'Malley, Billy Gerber, Margaret White, for years, and now she's a favorite among dezvous. WJJD's host of Sunday night listeners. (Photo by Connelly. Chicago.) -the Red Head Gal with the Uke,- (Connelly Photo.) Wanda Goll, Jimmy Travers, etc., "do their stuff" between the dances played by Charley Straight and his Orchestra. "wrecks," once a week is a lot of sa contrast to the many claims of It is quite a trick to keep the "air" but various broadcasting stations thru- program running smoothly, because fun and as Jack Nelson announces from the the Potato Sack, "These weekly shows A out the countryof havingthe largest must dress for one of their entertainers will very informal. in and most elaborate studios for radio acts, change makeup, do their bit "on be We'll let you programs, there recently came the the floor" and then dash into the Potato on all our secrets, our gayeties, and announcement from WJJD that the perhaps even some of our little quarrels, world's smallest and most informal studio so that you will almost smell the grease was now on the air. paint and see all the costumes." When arrangements for a Chicago It is that informality that makes them studio were made by Jack Nelson, just what they seem: a good time by a Managing Director and Announcer of handful of stage folk, back stage. They the Loyal Order of Moose Station WJJD, seem to feel that they are not putting a and this studio was located in the Palmer program out, but all the folks listening House, Chicago, and called the Garod in are really listening in, -sort of eaves- Studio, it was found that awaiting the dropping on their little weekly get - completion of the new Palmer House, together. in the hotel. there was no orchestra music Ralph Helps, Too So Jack went scouting around and made arrangements with the Rendezvous Cafe INCIDENTALLY, Ralph Shugart, the management to broadcast Charley Straight engineer of WJJD, deserves a good and his Orchestra every night as a part word for the excellent way in which he of the Chicago program offered by WJJ D handles the Chicago broadcasting. Moose - at 10:30 p. m. heart is 37 miles west of its Chicago He then noticed that many of the central (the Garod Studio in the Palmer entertainers there had voices which would House), and the Rendezvous Cafe is broadcast exceptionally well and he "got And here's Charley Straight, himself, another four miles North from there, and the itch" to put them on for some "hot" whose syncopating music aggregation furn- the lines, amplifiers and microphones are work, however, pre- ishes the jazz regularly from WJJD, begin- certainly well handled. programs. Their ning every night at 10:30 o'clock, Central vented their journeying down to the time. While the "Potato Sack Studio" will elaborate Garod Studio in the Palmer be used according to the present plans House, so the "back -stage studio" idea but once a week, that does not mean that was conceived, and programs are now Sack to do a turn "on the air," rush out, WJJD will not broadcast from the Ren- being broadcast every Sunday night be- change clothes again for the next show, dezvous only once a week, for every night ginning at midnight (Central Standard and repeat three or four times a night. as a regular feature of , the Chicago Time). Perhaps that's what makes this program programs of the Mooseheart Station, so peppy. Charley Straight and his famous dance Dressing Room as Studio WJJD has received hundreds of letters orchestra will contribute to the enter- THERE was not room to arrange for of applause on this feature. It just tainment. a studio which would be open to the happens there are few stations on the We'll venture to say that if you have guests of the Rendezvous, so a large air at that time. ?.Iiners and other a player piano and will walk over to it dressing room back -stage was chosen; workers of late shifts applaud heartily now, you will find at least five rolls on and because it would not be open for because it gives them something late your shelves bearing the signature of inspection, burlap was chosen for the Sunday night which was not available Charley Straight, for there is no one who material to deaden the room and make it before. has played piano records for as long a available for broadcasting. Inasmuch as this program is only once time as has Charley. Now is marked the So "Potato Sack Studio" is an ap- a week, it does not work the Rendezvous inauguration of the broadcasting of the propriate designation, both because of folks too hard. It certainly couldn't be last of the really popular, big and famous its hangings and size. Here the regular done every night or they would all be dance orchestras of Chicago. RADIO AGE for May, 1925 The Magazine of the Hour \- \\\\` Pick lips ,`,:..--A'... ``` :,,¡ ;, _

material appearing under the title "Pickups and Hookups by Our Readers" in RADIO AGE, is THEcontributed by our readers. It is a department wherein our readers exchange views on various cir- cuits and the construction and operation thereof. Many times our readers disagree on technical points, and it should be understood that RADIO AGE is not responsible for the views presented herein by con tributors, but publishes the letters and drawings merely as a means of permitting the fans to know what the other fellow is doing and thinking. THE MAY issue of RADIO AGE! Gosh! How time does fly. It seems as though it were just yesterday CONTRIBUTORS that we picked up the September issue, FELIX FREDERIKSEN JOSEPH LARSON THOMAS RODWAY said good -bye to Old Man Static and Delmar, Iowa Boise, Idaho London, Eng prepared for a Winter of ideal reception. DIAL TWISTERS Now we must prepare for a Summer of Name and it Address City ideal reception. It is possible Ed. Doughty.... 349 Armstrong Ave. Winnipeg, Man., Can. can be done, although it has not been r_.... done very successfully in the past. H. E. Potter 1 Hayden St Binghampton, N. Y. However, developments in the radio Edward Lange 116 Eureka Ave. _.____.______Wyandotte, Mich. line have been so good in the past Winter, Clemente Larranaga. Box 82 E. Pittsburgh, Pa. static, that we no longer fear the Summer Clarence J. Sneider_ 1008 N. Graham St. Milwaukee, Wis. spoiling all our good DX records and pleasant concerts, popular and other- J. M. Kloss . 3006 Courtland Ave- ____ -_Oakland, Calif. wise, from out -of -town- stations. \\'hen Dick Ray_ 1115 Ringwood Place Clinton, Ia. we look back and think of the giant Roy Studds, Jr Takoma Park, Md. ten strides made by radio in the past Robert Drake. 23 East Spruce St.._-_ Elmwood Place, Ohio months, I am sure most of us will realize just why this is going to be a real radio Don. L. Kooken Box 158 Garrett, Ind. Sum mer. Harry Schoy 5051 Pershing Ave. Cleveland, Ohio Take, for example, the super- hetero- Geo. D. Walter R. D. No. 4 Easton, Pa. dyne type of receiver, with its extreme Lyndon Kirley 612 So. Michigan At So. Bend, Ind. selectivity, portability and last, but not Frank Allen 1274 Glover Ave.__ Detroit, Mich. least, the little energy collector or loop antenna, that they use. This will prac- Ed. Haubner 689 Fifty Eighth St. Milwaukee, Wis. tically eliminate the old "distance elim- James Squire 22 Drake St Montreal, P. Q., Can. inator"- static. The reason for this is Lester Briske ...... ______...... 1658 N. Wisconsin St Racine, Wis. obvious to all of us. In the past, large, V. H. Miller_ R. F. D. No. 8 Greenville, S. C. flat -topped antennas were used, and would pick up disturbances from all Frank Barclay. Metchosin, Vic.. Can. directions. The loop antenna does not B. J. Salsbury Otsego, Mich. do this. Consequently most of the un- Jess Edmondson_ Elm Grove, W. Va. to desirable noises will not get through Bert R. Kissel_.._ _.___.__._1447 Madison Ave._ Covington, Ky. the set, to be amplified many times. C. F. -.__._ 1567 Buenna Covington, Ky. One must not necessarily have a super- Madison Ave heterodyne to operate his circuit on a Paul Wichert 125 Bostwick Ave Jersey City,N. J. loop. Several sets employing the reflex H. L. Remer Lakewood, Ohio principal are every bit as efficient, when N. B. Winter 614 Oakwood Ave Columbus, Ohio as well as when using a loop antenna, Ralph E. Riley .1711 Fifth Ave. Oakland, Calif. they use a large out -door one. Regenera- tive sets can be made to operate on a Valdan Baltz 120 Jefferson Ave Wheeling, W. Va. loop also. In our blueprint section T. F. Fino Gary, Ind. several months back one of these was Robert C. Potter R. R No. 3..._ Beamsville, Ont., Can. has given exceptionally shown, and it Kenneth Wyatt_._ 54 East St Fitchburg, Mass. fine results. It consisted of a detector tube and the customary two stages of W. Case.. _._...... _.._._...... 714 Shafer Ave. Saulte Ste. Marie, Can. audio frequency amplification. And Hugh M. Clark 127 Winter St Auburn, Maine there are plenty of other circuits that Robt. E. Blose_ 1339 Chew St. Allentown, Pa. will work just as well. 'D. F. Bullock..___ 827 Weeden St. Pawtucket, R. I. Another thing that comes with Spring. Nicholas G. Hart_- Bienville, Levis, P. Q. House -cleaning. Don't you think it J. Novak_ ...... ______5446 Rohns Ave Detroit, Mich. house -clean the Lewis might be well for us to Roy Anderson R. F. D. No. 2 Chanute, Kans. radio set at this time? Of course, it will to have your home William Benter 304 Park Ave Brooklyn, N. Y. be inconvenient A. Jr.__ 944 West itself turned upside down and the radio J. Myers, Capitol St.- Jackson, Miss. set at the same time, but it has to be Arthur W. White No. 3 Winn Park._ Woburn, Mass, done, and there is no time like the pres- Arthur J. F. Roth_ 634 N. Law St.___ Allentown, Pa. ent. Take a look inside the cabinet, Howard B. Hopping_ 325 Washington St.. .Muncie, Ind. clean out the dust, tighten up on the Bill Schwarte 4648 No. Kimball Ave..__Chicago, Ill. bolts and nuts, test the soldered connec- Ambrose Tobin 3116 Woodlawn Ave Valley, Neb tions carefully, and tighten up on the prong connections of the tube sockets. Little things like that all go to make the set work better, and after a hard Winter's corroded to such an extent that you are I am sure that some of our thousands of service on the part of the radio set, I not operating with a direct ground at readers could give us some very beneficial am sure it will be appreciated by it! It all. Yes, I think we had better take a "dope" on these types of receiving sets. might be well to call your attention to look. So don't be bashful. Let us have the your ground connection, which, being I am going to ask you once more for results of your experiments. usually made in the basement, is never information on portable receivers. Let \yell -I guess that's that, for this looked at. This might have become us have the benefit of your experience. time, and trusting that you will continue 42 RADIO AGE for May, 1925 The Magazine of the Hour to flood this department with your DX wind twenty -five turns of No. 20 single RADIO AGE, lists and reports, I;shall let you go on cotton covered magnet wire on one end Chicago, Ill. to the rest of this department. of the tube for the primary. Leave a Gentlemen: THE PICK -UPS EDITOR. space about one -quarter of an inch, and Many of the readers of the Pick -ups wind fifty turns in the same direction and Hook -ups columns no doubt have We have a circuit this month from on the other end of the tube for the refrained from using spider -web coils, Felix Frederiksen, of Delmar, Iowa. It secondary, the same size wire being used. a very efficient form of inductance, due is a variation of the well known "Ultra- This inductance can then be mounted to the fact that mounting them in the Audion," and Mr. Frederiksen says it on thin strips of bakelite for supports conventional way on the front of the is a "bear" for DX work. This circuit and a very good substitute is obtained panel, makes them clumsy and unsightly. is known as the Woods circuit, and for the variocoupler. The variometer This can be overcome, however, in a possesses several distinct advantages shown can be eliminated if you desire very simple and efficient manner; effi- over the ordinary ultra -audion. by winding a rotor on a small wooden cient because of the possible micrometer form to fit inside one end of the induc- adjustment and the absence of body It is very sharp in tuning and for that coil described. It (the rotor)_ reason is capable of reaching out through tance just capacity. DX should be wound with seventy -five turns The drawing explains the idea so heavy interference and doing real No. 28 single covered wire. work. The disadvantage of the ordinary of cotton clearly that there is little need for a circuit lies in the fact that it is difficult However, we think it would be best detailed description. to control the amount of regeneration to use the variocoupler and variometer. The wood strips to which the coils secured. This is overcome in this circuit The following parts will be necessary are fastened are cut from a cigar box. by the use of a plate variometer to secure for the construction of this circuit. They are glued to the inductance and to small blocks at the inside of the panel, an inductive feedback in addition to the 1 vario-coupler. usual connection from the plate of the to which are screwed small brass hinges 2 Switch Levers. from any hardware store. detector tube to the grid circuit. An Switch points, determined by number obtainable additional feature is the use of a vario- The brass rods threaded into the knobs of taps on coupler. and panel may be any convenient size coupler for the tuning inductance. By 23 -plate condenser. the use of a variocoupler in place of the and thread. The ends against the hinges Fixed grid condenser, .00025. should be filed round. tapped coil or the variometer commonly Variable Grid Leak. exceptional selectivity is secured If, for the sake of appearance of dials, used, Variometer. is desired to separate knobs in place of the usual broad tuning of the Double circuit jack. it the control single circuit receiver. farther than shown in the sketch, this Single circuit jack. is easily done by gluing a small block of Mr. Frederiksen advises us to use only Audio frequency transformer. empty thread spool between each wooden the best parts in constructing the circuit. Six ohm rheostat. arm and the coil. He says: "If poor parts are used, do not Twenty ohm rheostat. Rubber bands supply the tension, blame the circuit if it does not come up Bolts, nuts, wire, etc. tending to bring the coils into close in- to expectations." This advice applies Mr. Frederiksen seems very well ductive relation. By adjusting the bands especially to the variable condenser, pleased with this type of set and those on different prongs, the tension may be which should be of the straight line wave- of us who are using the old type "singles" varied. length curve type. A twenty -three might try this improvement and see Honeycomb coils mounted in this plate one, with a vernier dial attachment, what's what. \Ve have not quoted Mr. manner will appeal to the experimenter is what you will need. Frederiksen's letter, as it was quite long, using the three coil tickler regenerative The aerial binding post is wired to he being so enthusiastic about his set. circuit. Very efficient oscillator- couplers the top tap of the vario- coupler and to His DX list would "drag" most of us for the super -heterodyne can also be one of the switch levers. This arrange- out of our chairs. It certainly is a manufactured in this manner. For the ment shorts out the turns of wire on the "whiz." latter I suggest a form having an odd top half of the variocoupler that are not So for the benefit of all conerned, we number of spokes, say about seventeen, in use and reduces the dead end, losses, are going to pass this circuit along_ with a beginning or minimum diameter thus increasing the efficiency of the of one and a half inches. The pick -up, coupler. Mr. Joseph Larsen, of Boise, Idaho, secondary and tickler coils should be In place of the variocoupler you can gives us a suggestion for the mounting wound with twenty -five, thirty -five and wind a fixed inductance, if you so desire. of spider -web coils behind the panel, fifty turns of wire, respectively. On a bakelite or cardboard tube three which we think might prove of interest. Yours very truly, inches in diameter and four inches long, His letter follows: Boise, Idaho. JOSEPH LARSEN.

Circuit contributed by Mr. Frederiksen. It is a modified form of the Ultra- Audion. This circuit possesses all of the desirable qualities of the "single" Plus the selectivity of the three circuit tuner. RADIO AGE for May, 1925 The Magazine of the Houe 4 It's a good stunt, Dial Twisters, and an easy one, too. Not only does it keep the coils out of sight, but it protects them from dust and dirt, preventing injury to them at the same time. Thanks, Mr. Larsen, for your idea.

A letter this month from 91 Hamilton Road, Golden Green, London, England, N. \V., as follows: RADIO AGE, Gentlemen: May I, from the other side of the Atlantic, contribute my quota to your very interesting journal? It is always interesting to read of current radio opinions in your paper and it gives much information as to the trend of receiver design on your side. In the attached list I give a number of stations I have heard on my resent receiver, which consists of a detector valve, followed by one stage of audio frequency amplification. Over here, this is practically the standard set. Very few experimenters use radio fre- quency valves, being of the opinion that it complicates tuning and really only amplifies the "mush" which accompanies the weak signals. The only uncommon thing about the hook -up enclosed lies in the grid return lead. The set is extremely simple to make and is most surprisingly selective. In fact, the local station 2L0, using a power of one and one -half K. W., and only five miles away, is completely cut out on two degrees of the condenser. It is well worth a trial by anyone desiring extreme selectivity, together with full weak Showing method of mounting honey -comb or spider -web coils behind the panel. This volume. It is very sensitive to is quite a novel idea, contributed by Mr. Larsen. signals, as the enclosed list vouches for. By the way, do you think it will merit a D. T. Badge? Jos. M. Kloss, of Oakland, Calif., has scribed in the March issue of RADIO Now, I am oing to ask a favor of you, a set using the Roberts circuit, with AGE. I have tried coils of all sizes, or some of the readers of the Pick -Ups which he is "knocking 'em dead." shapes and forms and have come to the and Hook -Ups section. Will somebody KDKA was heard the other day on it, conclusion that the spider web form of Iet me have a circuit or hook -up, as I and he held them over an hour and a inductance is the most efficient. Any believe everyone calls them, of a super- half. This is pretty good, as it was only of the readers of this section who want heterodyne, using up to five valves, with 5:30 p. m., Pacific Coast time. Some 'dope' on this circuit might get in touch the audio frequency amplification ob- of the other stations that he has listened with me." tained by a reflex arrangement? I to in the past few weeks are KFHR, As J. A. was good enough to offer his should be very grateful if anyone can CFCN, KFNV, KDYL, KFSG, CHBC, services, let's see that some of us mail do this for me, as such circuits are prac- WOC, WOAW, \VIP, KYW and KTHS. him a card. He lives at 944 W. Capitol tically impossible to obtain in England. His set is only a two "tuber" and we St., Jackson, Miss. Yours very truly, think this is pretty good work. THOS. RODWAY, Jr., T. F O'Connel, from "out where the British G -2ADG. Howard B. Hooping, Muncie, Ind., \Vest begins" wants to know if any of is doing some mighty fine DX work on us have ever thought of using a breast We are printing Tom's letter and the his "Hopwood" set built according to drill for coil or radio frequency (long diagram of the circuit that he says most RADIO AGE specificaions. Such sta- wave) transformer winding. This is a of the English radio fans use. L -1 is the tions as KPO, KGO, KOA, and WQAM good stunt, and quite a few of the "old primary and consists of twelve turns of are received by him regularly. He also timers" use it all the time. Nevertheless, wire wound over L -2, the secondary, has a crystal set on which he has received we are going to pass it along for the which consists of eighty-five turns of KDKA and WGY. benefit of the newcomers in this radio fairly heavy wire. L -3 is the tickler and business. Some breast drills are geared consists of seventy turns. Arthur J. F. Roth, 634 No. Law St., as high as six to one, and you can easily As can be seen, this circuit is one of Allentown, Pa., is having a fine time see that your work is reduced fully 75 our "old time" favorites, and gives very "pulling in the long ones' on his three - per cent when you wind by this method. good results. Below you will find the circuit outfit. His DX list runs up into All you have to do is to fasten the form, DX list, that Tom thinks will get him the "house" numbers. or core, to the end that takes the drill. a DT button: The usual method is to insert a reamer 2L0,6BM, 5SC, 5IT, 2EH SPY, 2ZY, We have a letter from one of the fans a trifle larger in the bit than in the hole. SNG, 2BD, SNO, Ecale Supr, Paris, on the Eastern Coast who is uing one You will have drilled in the core of the "Petit Parisien", Radiola, Eiffel Tower, of RADIO AGE's latest Reinartz hook- transformer, force the core over the bit, Radio Electrique, Brussells, Radio Iber- ups, with which he is getting wonderful fasten the starting end of the coil, and ica, Madrid, Berlin, Frankfurt, Ham - results. Any of you fellows who are "let her ride." Try it, fans. It works burg, Radio \Vien, Vienna, Bremen, in doubt as to the practicability of the very well. \VGY, KDKA, WBZ, CKAC and WEAF. Reinartz circuit might drop him a line How many of us would love to have and get his opinion. \Ve have a letter from Robert E. Blose, our log read like that? \Vhat could be of Allentown, Pa., who has had a receiv- sweeter? But, then, I suppose perhaps J. A. Myers, Jr., says: "I have read ing set just three weeks, and has a list Tom should like to have our KFIs and the article on the two tube "Ultra - of stations heard so long that it reads KPOs, on his log. Anyway, we think Audion" and I would like to say for the like a broadcasting station list. To print it is just fine and we shall ship him a benefit of those readers who are interested it would be impossible, so we will have to DT button, "right quick." Is it all that I have done quite a bit of experi- award him a DT button without dis- right, fellows? Absolutely, Mr. Kelly. menting with the Ultra -Audion as de- closing his log. (Turn the page) 4 l RADIO AGE for May, 1925 The Magazine of the Hour recommending this publication in no uncertain terms. Thanking you again, I am Yours very truly, RALPH E. RILEY, 1711 Fifth Street, Oakland, Calif. Letters like this make us feel real "chesty." And they prove conclusively H T.+ that our slogan is correct: "Let Our / L3. Hook -Ups be Your Guide." Radio Age, Inc., Chicago, Ill. Dear Sirs: I am sending herein a list of stations which I have received during the months of November, December and January. I All of these stations were received on a L1 two tube Reinartz Tuner, using peanut ,0005 tubes. This set has given loud speaker volume on locals, and on some of the LZ vvw distant stations the announcer can be understood with the phones lying on the table. Hoping that my list will win LT. -+- a Dial Twister Button, I remain, Yours truly, O JAMES SQUIRE. LT - 22 Drake St., Cote St. Paul, Montreal, P. Q. KOKA, WBZ, WTAS WIP, WMAC, 'WHAM, WLAW, WTAM, KY ,WE WDARIXAD,O WDAL, WOS9 X51 WDAE, WBAY. WJZ, WDAF, WCAL, WARD, WAX, WSAJ. WJAS, WWJ. WAN, WREO, WEBA, CNRO, The most popular type of receiving WCAP, WHAS. WON, WOR, WOC WRC, WSAI, WW, circuit WEAO, KSD, WEAR, WRAR, WLW, CECA. in the British Isles. One of our readers re- ports phenomenal success with this hook -up Quite a nice list, isn't it, fellows? We think he well deserves a Dial Twister Button. The lads up in Canada all seem to have ideal reception. RADIO AGE, Hugh M. Clark writes us to let us merit a DT button. My list is not a Chicago, Ill., know he thinks that RADIO AGE is very long one, but what I take the great- Gentlemen: the best on the market. He has a Clapp - est pride in is the fact that' can get these My being somewhat of an experi- Eastman, three -tube regenerative set, stations at will, and hold them as long menter with the regenerative principle with which he has received WSB, PWX, as I want to listen. The circuit is noth- has resulted in a modification of the KWAQ, KFOMI, CYL, KOA, KFKX, ing phenomenal, being quite common. so- called three circuit arrangement that CFCN, KSD, WFAA, KFRU, KFI and Here is the list: WGR, WBZ, KDKA, really does what I consider creditable others too numerous to mention. We \VGY, WEAF, \VNYC, WCAE, WFI, work considering the number of tubes call this pretty good reception, consider- \VSAI, WLW, WOC, KYW, KSD, used. ing that he is in the most eastern state \\'HAZ, WMAK, WJY, WLS, WAHG, And having built and tested several in the union, and we will award him his CFCA, \VEBH, WCBD, W \VJ, WQJ, of these modified sets and found the DT button. He lives in Auburn, Maine. \\'HAS, WEAR and KDKA. circuit to be no freak, I am sending in Yours very truly, a diagram of the hookup and hope you Kenneth Wyatt, 54 Cast St., Fitch - ROBERT C. POTTER. will pass it on, through your columhs. burg Mass., writes us as follows: R. R. No. 3, Results show that it will give loud- RADIO AGE, Beamsville, Ont., Can. speaker volume on two tubes for a Chicago, Ill., Your list, Bob, as you say, is not very considerable range, and in selectivity Gentlemen: long, but considering the fact that you I think I may safely say that it is on an Looking over back issues of RADIO receive these stations at will, we think equal footing with any neut or super - AGE, I noticed a record made with a it is a very good one and will award you het, when using a short antenna. Rather "Cockaday" receiver, of thirteen sta- your DT button. Also, we are welcom- strong, that, but -quite true, by test. tions in thirty -nine minutes. Deciding ing you to the RADIO AGE family. Along with the hookup I am sending to beat this, I sat down and received a list of stations heard on each of two twenty -nine stations in thirty minutes. Valdan Blatz, of Wheeling, W. Va., sets using this hookup, each being at Am I entitled to become a Dial Twister? has a set using UV199 tubes, with which different locations. I only give the most All stations were heard on my two tube he has received over 75 stations in the consistent of distant stations and only Cockaday. past month. He wants to know if this a few of the nearer ones, as they are too Yours very truly, will admit him to the Dial Twisters. It numerous to list conveniently. KENNETH WYATT. certainly will, and we shall send him his Set No. 1, two tubes: WREO. WTAB KOA, WSAI, WLS, What do you think, fellows? Pretty WDAF. WEBR, WTAM, KAJ,CFCA, *LW, KPO, WCAE, button at once. His circuit is the regular EFI, WFAA, wOe. KGB' KYW. Clem A's too numerous. good. Can any one do better? We shall old "stand by," the three cil'tuit outfit. Set No. 2, one tube: kFON3KFAB, WARM, WEE!. WMII, KCO, KOA, WBZ, CAtC, KHJ PWX, WAA9. see. Meanwhile this will stand as a CFCA, WJY, CKAC, CKY, KF1, WOE, CYL, wCX. record and Kenneth will be awarded Here is a letter from an ardent booster Close A's too numerous. the DT button. of RADIO AGE. A record was made several nights ago RADIO AGE, when 45 stations were tuned in and Another Interesting Letter Chicago, Ill., identified (on done tube) within 33¡ RADIO AGE, Gentlemen: hours, the total combined mileage being Chicago, Ill., Just completed building a wave trap 37,000. Gentlemen: from a diagram published in the RADIO I am a constant reader of RADIO Glancing over a copy of RADIO AGE AGE ANNUAL for 1925, page 66, AGE, which is always interesting. which I purchased yesterday for the figure 4. And with the usual RADIO Hoping for a DT button, first time, I noticed your "Pick-Ups AGE reliability, it works wonderfully V. H. MILLER. and Hook -Ups" department, which in- well. R. F. D., No. 8, Box 34. terested me very much, and as I have RADIO AGE ANNUAL is worth This is a pretty good list, and will give done some rather good DX work myself, many times the purchase price to any some of you DT's a mark to shoot at. I thought I should like to see if it would experimenter and I take pleasure in Space will prohibit our publishing the (Turn to page 56) RADIO AGE for May, 1925 The Magazine of the Hour 45 Lacault Scores Alain/

PATENT PENDING 5°° 0005 mid. Capacity

The new Ultra.Lowloss condenser is the latest improved radio device de- signed by R. E. Lacault, formerly Associate Editor of Radio News, the originator of Ultradyne Receivers and now Chief Engineer of Phenix Radio Corporation. tILTR7t-bO1r)bO$8 CONDENSER

LIKE every Lacault development, this new Ultra -Lowloss Condenser represents the pinnacle of ultra efficiency-over- comes losses usually experienced in other condensers. Special design and cut of stator plates produces a straight line frequency curve, separates the stations of various wave lengths evenly over the dial range, making close tuning positive and easy. With one station of known frequency located on the dial, other stations separated by the same number of kilocycles are the same number of degrees apart on the dial. In the Lacault Ultra -Lowloss Condenser losses are reduced to a minimum by use of only one small strip of insulation, by the small amount of high resistance metal in the field and frame, and V.ILTTZZ VGRP1ER, by a special monoblock mounting of fixed and movable plates. TUNING CONTROL At your dealer's, otherwise send purchase Simplifies radio tuning. Pencil - price and you will be supplied postpaid. record a station on the dial- there - after, simply turn the finder to your pencil mark to get that station in- stantly, Easy -quick to mount. Eliminates fumbling, guessing. Fur- Design of low loss coils furnished free with each condenser for amateur nished clockwise or anti -clockwise and broadcast frequencies showing which will function most efficiently in gold or silver finish. Gear ratio 20 to 1. with the condenser. Silver $2.50 Gold $3.50 To Manufacturers Who Wish to Improve Their Sets The Ultra-Lowloss Condenser offers manufacturers the oppor- tunity to greatly improve the present operation of their receiving sets. Mr. Lacault will gladly consult with any manufacturer regard- This seal on a radio product is your ing the application of this condenser to any assurance of satisfaction and guar- circuit for obtaining antee of Lacault design. maximum efficiency.

PHENIX RADIO CORPORATION, 116 -B EAST 25th ST., NEW YORK Tested and Approved by RADIO AGE 45 RADIO AGE for May, 1925 The Magazine of the Hour Standard Radio Receivers

Last month RADIO AGE inaugurated a new department called "Know Before 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 feature, and accordingly it is continued in this issue and will be a feature of all forthcoming numbers of RADIO AGE. Readers are invited to write us concerning the sets in which they are interested, and manu- facturers also are asked to send us material describing their sets.

Telmaco Receiver Useful for Records of Distance and Volume with Summer Trips Howard Set The Telmaco Acme Type P -1 Receiver, shown in the photograph, is manufactured by the Telephone Maintenance Company of Chicago and contains .. some new features in portable radio construction . ...., . . .._...-._.. . s_. - - _ .. that will undoubtedly prove popular with the Sum- .-._ _.. mer radio fans this year. The Telmaco Acme is a four -tube reflex receiver designed to assure selectivity, distance, clarity and volume, with minimum battery consumption, even under the stress of Summer conditions. The set retails at $125. and weighs only 26 pounds in its complete carrying case for traveling. The loop aerial and loud speaker are built into the set. The loop is the only aerial needed. The size of the case when closed is 8 inches wide. 10 inches high and 18 inches long. The set can be put into operation instantly without any hooking up other than that already contained in the outfit. t The upper portion of the lid is lowered when the set is ready_to be operated. The Howard 5 -tube Neutrodyne, made by the Neutrodons, variable condensers of minute ca- Howard Radio Company of Chicago, has been de- pacity between plate and grid in the tube, are easily veloped during the past several months until at adjusted to perfect neutralization. This adjustment present it is a highly efficient receiver and a very is carried out at the factory and need not be repeated popular one among the DX fans. To attain the last degree of clarity in sound, three The Howard Neutrodyne was designed primarily neutrodons are used instead of the customary to eliminate annoyances which sometimes exist in two. radio reception. such as restricted range, howling. Heavy phospher bronze contact arms, spring re- indistinct reception, and interference of local broad- inforced, insure contact on sides of the tube terminal casting stations. pins in the Howard sockets, giving maximum tube The cabinet of this improved receiver is of 3-4 inch efficiency. Panels and sub-panels are made of flaw- black walnut, high polished. It is fitted with a less Formica. or Bakelite, no wood being used except nickel- plated hinge. cover stop, and felt pads. The in the enclosing cabinet. Wiring is squared entire set can be removed from the cabinet by dis- bus -wire. connecting the wires from the nine binding posts, The Howard set is designed to use five tubes, all removing two machine screws from the bottom of alike, of the "A" type. It operates satisfactorily The lettering and decorations on the inside of the the cabinet, and sliding the panel upward in its slots. on either indoor or outdoor antenna, and for bringing set are done in silver tone by the new Telmaco Neutroformers, which are radio frequency trans- in coast to coast stations on a loud speaker, a single Pyrogravure process. The loop is contained in the formers especially designed for Neutrodyne use, are outdoor wire fifty feet long is advisable. The Howard walls of the case, being concealed from view and wound on hard rubber tubing. The primary winding set will receive with uniform efficiency over a mini- protected from mechanical injury. The panel is so is invisible, the wires resting in grooves cut in the mum range of 190 to 610 meters. assembled that it allows instant transfer from carry- rubber with rigid accuracy. by specially constructed The price of the Howard five -tube Neutrodyne ing case to a mahogany cabinet made by the Telmaco machines. is now $200. concern. Likewise the mahogany case may be trans- ferred to the portable arrangement. Three stages of r. f. amplification, three stages of audio frequency amplification and crystal detector ably comparable with any five -tube receiver of the are used. Four UV199 or C299 tubes are used with same type. It was designed by R. H. Martin, general a combined B battery consumption of .24 amp. sales manager of the company, to eliminate oscilla- Practically all tuning is done with one flinch tion over the entire wave- length range, and this it control. can be said to accomplish satisfactorily. The Marwol is small and accordingly is easy to carry and handle. while not taking up much room if "Marwol Baby Grand" is used in the home as a permanent fixture. The Mar- Ready for Vacations vol people decided that the 5 -tube tuned radio frequency type of receiver was the best suited to A new receiver that is particularly light and com- portable needs and likewise one of the most popular pact and easily convertible into a portable set for circuits of the day, so these features were incorpor- Summer use has been placed on the market by the ated when the new Baby Grand was designed. Marwol Radio Corporation, 85 Mercer street. New York City. Operadio Set Entirely Self- Contained For néarly three years the Operadio Corporation of Chicago has concentrated on one model, with a view- to obtaining quality of tone, greater power and range and loop reception and big battery supply in a portable, entirely self-contained unit. The 1925 Model Operadio, a six tube, tuned radio through special condensers of Operadio design and frequency set. with six "A- batteries, four big 22 1. make. volt B batteries and a built in loud speaker, is par- ticularly interesting in its design to obtain reduction These condensers, which are of low loss design. This is known as the "illarwol Baby Grand." and of electrical losses. The longest wire lead is 234 have an eight-to-one reduction on the knob and back comes equipped for storage battery use, but may inches. The tubes are supported in aluminum con- lash is eliminated by means of planetary drive. An be changed to operate on dry cell tubes. tainers which also house the transformers. grid leaks. exclusive feature is a fuse on the "B" battery circuit While the Marwol Baby Grand is much smaller etc., impregnated in special wax to eliminate at- which prevents the tubes' burning out. The tone than the well known Marwol Model A-I, it contains mospheric variance. of the Operario is clear and undistorted. and dis- identically the same 5 -tube tuned radio frequency The cover serves as the aerial by a design patented tance is equal to many eight -tube sets. .111 long circuit that is known for selectivity, range and ease by the Operadio Corporation. range reception can be had on the loud speaker. of operation. The Baby Grand retails for S40. The 199 type tube is used throughout, and a volt- The price, complete, is now $189.00. A loop or outside aerial may be used, the latter, of meter operated by a convenient two -way switch The Operadio can be used as an ornamental course, giving the best distance. The Baby Grand shows the operator instantly his "A" battery draw decoration to the home or it may be carried about has been found to produce results similar and favor- or his "B" battery reserve. Two dials tune the set easily. RADIO AGE for May, 1925 The Magazine of the Hour 47

:J!/JJII'l_l%JI.Ill!/1!!JJ0.!/JI_lN_J'J_0.e/Jl!/J0.!/JIJ_l_.tV_.eJ_JV_dplVJl.IeIJWJWJI'l%Lle/J0.!¿JlleA!!-IUVJWJLIe/JLIeIJA!AWJLI WJVJJLVJ WJl_le/Jl%JI._l lL_VJI Howard 7 5 Five Tube Neutrodyne

To build the best-the ultimate -in radio receiving sets regardless of cost has always been our ideal and our aim. That we have succeeded is best ev- 5 idenced by the fact-not what we claim but what an actual demon- stration will prove to you. Hear the Howard Five Tube Neu- trodyne at any Howard dealer and then decide.

Licensed by 2, en ,y. dent Radio Manotada°' $

1 TRODYN tn Howard Manufacturing Company, Inc. 5 211923ònG Apn; I1g E -Ps"P,yepslp50p90anG24 451 -469 East Ohio St. Chicago IF Ha1`ne 0!herPatents PeeWnp B9?za t

á't rreYlr~ÌoÌÌia`fiÌ í/`itYe\ÌÌÍe:ÌfÌgÌÌßiÌPi:AÌ%iRribNÌrßrltYi 1ÌaiiÌYsiRÌOfia\i e Ìií`ll IreinvÌÌa`Llb*efYí`il BÌ/171raÌatlfYeiÌÌrïYfiíi` IÌAÌfYsYUiAÌPÌoVIYA11Y11YoiÌ ATTENTION Set Manufacturers send for IF YOU ARE INTERESTED Prices Smashed! IN CUTTING DOWN YOUR Bulletin 94 Quality Not Sacrificed PRODUCTION COSTS IT Here is real battery quality, guaranteed to you, at WILL PAY YOU TO COM- prices that will astound the en- Whether you plan to build or tire battery -buying public. Order MUNICATE WITH US. direct from factory. Put the Dealer's to buy a receiving set, it will Profit in your own pocket. You actually save YEARS OF EXPERIENCE pay you to know something about much more than half, and no that you can be the convinced of true quality and performance. we "insides" of radio. This book- gives HAVE ENABLED US TO let gives you the "inside dope" on Written Two -Year Guarantee GIVE MANUFACTURERS some of the recent inventions em- Herein your protection! Noneedtotakeachance. bodying the latest ideas of radio Our battery is right -and the price is the lowest THE BEST POSSIBLE evermade. Convince yourself. Read the prices! engineers. In this bulletin is full Special 2 -Volt Radio Storage Battery, $3.7S information about the Special 4 -Volt Radio Storage Battery, 6.00 PRICES CONSISTENT 8 -Volt, 60 Amp. Radio Storage Battery, 7.00 6Volt, 80 Amp. Radio Storage Battery, 8.00 WITH HIGH QUALITY. Premier 6Volt, 100 Amp. Radio Storage Battery, 8.50 6 -Volt, 120 Amp. Radio Storage Battery,11.50 DROP US A LINE AND "HEGEHOG" 8 Volt, 140 Amp. Radio Storage Battery,13.00 Audio We ask for no deposit. Simply send name GET QUOTATIONS. DO IT and address and style wanted. Battery will Transformer be shipped the day we receive your order NOW. WE MAY BE ABLE Ratios 1 to 3,1 to 4, Express C. O. D., subject to your Ratand l to5. 51.50 examination on arrival. Our TO SAVE YOU MORE io I to 10. S4.50 guarantee accompanies each battery. We allow 6% This light weight audio transformer has earned a THAN YOU IMAGINE. place in the very front rank for its remarkable discount for cash in full volume. and pure, natural tone. It is 100% self with order. You cannot shielded against foreign noises. lose) Act quick. Send your Its small sise is a surprise to everyone. It cuts the order today -NOW. space requirements for audio transformation in two. This is a big advantage in portables and makes it THE BARSOOK CO. ideal for neat and compact wiring. Arrow Battery Co. Free Hookup Diagrams also sent on re- IRIS South Wabash A ve. 53W. JacksonBlv'd., Chicago, Ill. quest; all popular types. Address, * Dept. 1 Chicago, III *HERLSACiMAET Vrrmipr Elprtrir lita REFLEX 3803 Ravenswood Ave., Chicago Erla 20 Ft. Mast $10 -Acme- Harkness 40 Ft. Mast $25 Dealers: 60 Ft. Mast $45 Write for Send for Discounts t.0 steel coastreetion. C.m- literature mshead pley.ol° We any and the freight. MIE1i: - ROSS S. W. HULL & CO. FREE Dept. 1- 6.2048 E 79th St. Blueprint 123 W. Madison St Chicago CLEVELAND. O. Quality ?radio Parts * Tested and Avvroved bai RADIO AGE 48 RADIO AGE for May, 1925 The Magazine of the Hour A New Power Supply Receiver (Continued from page 14) The Fire Parts listed are given under headings Underwriters' that indicate their use in the receiver. "B" Rectifier System 8 Audio Frequency Transformers Code requires that- 2 Two Mids. Fixed Condensers 2 Tube Sockets Each lead -in wire shall be 1 Bell Ringing Transformer-13 volt provided with an approved pro- 1 20 ohm rheostat tected device properly connected 10 feet flexible rubber covered lamp cord and located (inside or outside 1 push switch 1 separable plug the building) as near as practic- Audio Amplifier able to the point where the wire 2 Audio frequency transformers enters the building. The pro- 2 tube sockets tector shall not be placed in the 1 .004 mfds. fined condenser immediate vicinity of easily ignit- 1 .0025 mids. fined condenser to 2 binding posts able stuff or where exposed Tuning Circuit. intlamallem gases or dust or 2 length. of insulatingsilk inch diameter. 3 inch Ward livings of combustible materials. 1 -2 lb. No. 22 double silk covered magnet wire The protective device shall be 1 small clip connector or spring clip for tap adjustment, an approved lightning arrester 2 binding poste which will operate at a potential 1 tube socket five (500) volts or 1 double mineral crystal detector of hundred 2 .0005 mid, low -loss variable condense,, less. Filament Lighting 1 8 volt Bee ringing transformer 1 "C" battery Buy a Jewell Arrester. 1 potentiometer 1 10 or 15 ohm rheostat (In brown porcelain case.) Extra Part. Aerial equipment Price It has been passed or ap- speaker Bus bar or No. 16 fixture wire for set connections $1 10 proved by Underwriters. Cabinet and bewboard about 20 by 12 inches I Send for Jewell Radio The circuit diagram is laid out ap- Instrument Catalog No. proximately as the parts are to be placed 15 -A. on the baseboard, and further suggestions may be had from the photos. The "B" Order from Dealer apparatus should be compactly mounted at the rear, so as to allow plenty of room for the important tuning apparatus at ewell Electrical Instrument Co. the fore. The audio amplifier is located 1650 Walnut St. - Chicago along the left edge of the board, starting at the front. Two binding posts are "25 Years Making Good Instruments" placed at the rear of the audio amplifier for the speaker and two others at the right hand rear corner for aerial and ground. The power lead is brought in at the rear center and is held down by a simple half -round clamp bent from a piece of iron or brass and fastened with two screws. A "U" shaped clamp is bent from a small sheet of iron or brass as a clamp to hold the "C" battery, and another clamp of smaller size made to fasten the 2 mid. condensers. The shape of this clamp varies according to the Want to make big. easy money? Learn how toi natall,operate,repair, construct mak of condensers chosen -these being and sell Radios. Write now for facts for purpose of filtering the ripple about the amazing opportunities for the Radio experts, and our special offer of a out of the rectified "B" voltage. FREE 1000 -mile receiving set, and how you can quickly train at home by mail. Be a Radio Expert Coil Construction No previous experience necessary. Anyone to ri ip p ry in- TO TUNE the grid of the R. F. tube with ordinary education can now learn Radio quicklyunderour simplified bome'stodyplao. rbprinciple gie and to couple it to the aerial, a special We need men right now to represent our k. lash, isCn ; Association. Be the Radio expert in your coil is built, 40 turns of the magnet wire neighborhood. Get your share of the big all tuning sec on one of the lengths profits. Hundreds about you want Radios and are tightly wound You can earn enough finite standard advice bow to operate. ail tse . of tubing, taking "twist" taps at the money right from the start to pay for course. y. difficult e -... Nothing it. sei D 1 5th, 8th, 11th, 15th, 20th, 25th, 30th -.. Low cost and easy terms. eú The coil ends may best 11II1 dise and 35th turns. StNeaark.t. be connected to soldering lugs fastened FREE 9R Catmsboll at the edge of the tubing by short 6-32 -MILE machine screws. An extra screw and lug 1,000 CCURATUNE is provided at one end for the antenna -- Receiving Set accosrcae Dr. this lug a short piece of Don't miss this big special offer to supply MICROMETER CONTROLS wire. From FREE all parts necessary to construct a flexible wire is brought to a clip con- high-grade 1000 -mile receiving set. You can sell this set alone for practically the entire nector, whereby contact from the aerial cost of the course. Send for the facts now. Find out all about this big -pay field. Address may be made to any one of the taps Radio Association of America provided. The taps are merely twists in 4513 Ravenswood Ave.. Dept. 25 Chicago, W. the wire, scraped as the winding goes LISTEN INI - on and twisted firmly. Before the coil Radio Age KYW, 11:30 pa is used, these are soldered for greater at Perfect Reproducer strength and better contact. to 1 a. m., Saturday, May 2. Torte loud and pleasing. Handsome material and design. Next, a coupler is made for coupling Radio Age at WEBH, 11 to 12 Black, $22.50 Shell, $25.00 the R. F. tube to the crystal. To control p. m., Tuesday, April 28. AMERICAN ELECTRIC COMPANY the sensitivity, its primary is made Stata and 64th Sta., Chicago TWO ALL-STAR POPULAR PROGRAMS variable, and, most any coupler on the . Tested and Approved by RADIO AGE RADIO AGE for May, 1925 The Magazine of the Hour 53

vibration is at one moment all energy of bending and at the next all energy of motion. The effect of the impulses is cumula- tive. Each increases the energy of vibra- tion by a little, until finally the vibra- tion is large enough to set up frictional resistances which use up all the further impulses. Thus the small impulses give rise to enormous forces, but these are actually supplied by the elasticity and mass of the bridge. The bridge in a sense breaks itself. Each Ware Adds to Energy TN A similar manner the weak waves coming to a receiving antenna set up in its circuit only a tiny electromotive force, far too small, in fact, to pass the the necessary current for an audible signal through either condenser or coil alone. If, however, the circuit is properly tuned, each wave adds to the charge on the condenser and thus to the current which flows in the circuit, until at length it is so great as to requisition all the weak electromotive force induced in the circuit by the waves. dear! The circuit then oscillates steadily, KEEP reception but with vastly greater electromotive forces upon the coil and the condenser Keep it clear. Keep it loud -with all the vol- than the tiny voltage directly induced ume your set should have. Keep the battery by the waves. It is these relatively large at top notch -fully charged- peppy. electromotive forces which are analogous to the large bending force and the force The Tungar charges your storage battery over- associated with the momentum of the night while you sleep -and at a cost of hardly bridge vibration. It is these large elec- more than five cents. It's easy! Just two clips tromotive forces which overcome the -and a plug for the house current. Or you can large oppositions of condenser and coil make a permanent connection, and just throw to the passage of the current. Taken a switch. Keep your set at its best all the time around the circuit, they are nearly equal -with a Tungar. The Tungar is a G -E and opposite, their small difference being product, developed in the electromotive force induced by the the great Research Laboratories of Gen- waves, but the detector circuit is con- eral Electric. nected to receive their full effect. The New Model Tun- It follows from these considerations gar charges radio A that, if we could make the resistance and El storage bat- OFF. of teries, and auto bat- 'unbarReg. U. S. PAT. our receiving circuits small enough, teries Two ampere waves, however weak, could size (East of the produce Rockies) . . . $18.00 appreciable voltages upon the detector. A Tungar is also On the other hand, the effect of waves available in five am- Tungar -e registered trademark -ìs found only for which the receiving pere sire, design un- on the genuine. Look for it on the name plate. circuit is not in changed (East of the tune is to alternately aid and oppose Rockies) $28.00 Merchandise Division the natural oscillations of the receiving 60 cycles -170 volts General Electric Company, Bridgeport Conn. circuit, with the result that very little current flows and the detector is prac- tically unaffected. A circuit may be tuned either by vary- GENE AL ELECTRIC ing the capacity of its condenser (elas- ticity of the circuit) or by the varying 5eó Y its inductance (electrical mass of the Hear What YOU Like circuit), and it is immaterial YOUR OWN Hams ana Address Henninger Aero -Coils which, Printed Free on Thank you Cards Give more Volurnegand Sharper Heu what YOU Me. Stations glad - Tun just as it is possible for a violinist to tune j ea n . únky0a- 1b k The Cue lOwlessjiadoctaoce. 95 air ,_teP Y Os-Ortrvst ú a string either by changing dRA. sse AyoITrqueEN(pt- dielectric Denote/is, air spaced its tension ÁÌ hi 106 -5100; 200 lama.ngs ' -f.uüed CPr°r`°"` - Pn. 61-4 horn., Sec. 60 turns.. Greatly or the length of the vibrating portion. {6.000.3epaí4dif6pay with order. improves toned R. F or any net image Limbic inductance. More volume: better In conclusion, when you see your MONEY REFUNDED If Net DeEgitd selectivity. At your dealer'. or direct Quality cards. High grade prank.. $3.50 each. 510.50 the complete set of S. long distance radio friend silently turning With at Show. suc Station Ig b. doh tords, .Smoke, ate Stature lut by HENNINGER RADIO MANUFACTURING COMPANY ' FREE LOG wave loth Distance map Beastifil cover. W.Ison ave., Dept. 32 Chicago a dial with a distraught air, you may eMn 1772 feel sure that his anxious face does not RADIO PRINTERS. 90025 Street. Mendota oïl. indicate that he is afraid of losing a single word of the speaker. He is merely absorbed by the delicate task of so ad- SUPER -HETERODYNE . If Your Neut's Gone Back On You- Ultradyne- Haynes Griffin- Remler Rebuild it to this hladag Coast to Coast Circuit, sums justing the electrical stiffness no or elec- Dealers: Send for Discounts old panel. almost same parts. but Nightmare trical mass of his receiving of N eutrabsatloa. Twenty -two feet of gold sheathed circuits that wire. with only extra part and simple. complete instruc- they will allow the maximum current tions -$5.00 prepaid anywhere. Nothing more to buy. Over a thousand "converted" Nauta are daily bringing to flow and thus set up the greatest possi- HUDSON -ROSS is dean, resonant volume from Coast to Coast Derails -10c. 4 8-page meaty catalog of PARTS ONLY -10c. ble voltage across condenser, coil and Kent, Ohio grid. 123 W. Madison St. Chicago Kisdeg Radio Laboratories, 3 Tested and Approved by RADIO AGE 'F 54 RADIO AGE for May, 1925 The Magazine of the Hour

cf A W fe-~.0 cLe,. Q. s.7-: Some Radio Programs and C.aeocc Personalities 450v EDISON BATTERY' in five sections, complete with (Continued front page 30) magnetic rectifier, sell $100.00 or consider exchange deal rtet,C,gq Kessell, Leonard Van for 1000 -1500 v DC 110 v AC motor- generator, Russell, Jimmy er also have New rotary gap with 110v Uni Berg, Virginia Flohri or the Packard moo .00. 10,000 v open core transformer, $16.00 .01 Six Orchestra, it will be seen that prac- glass plate condenser $3.00. C. Arnold Edwards, clAW, North Sydney. N. S -. Canada. tically none of them can be granted. Yet the public seems to sense the willing- ness on the part of the station and the artists to co- operate in giving the public what it wants, as the requests increase week by week. During the mysterious Double Voiced Octavos' first programs, the main studio of KFI was called from over 600 miles away. During the fifteen minute, one - act play given on Hallowe'en, a dozen long distance calls were made from out- lying points in Southern California. Anything that arouses curiosity will produce telephone calls. Many long lost friends have been brought together over the telephone at KFI. A singer's name will be announced, then someone who has known someone A SMALL PORTABLE SET FOR THE AUTO, BOAT OR HUNTING LODGE., of that name will call in and hesitatingly KEEP IN TOUCH WITH BUSINESS AND THE FOLKS AT HOME. ask if "Sophie Klotz, who just sang 'Sweetest Little Feller' -did she ever Item No. 68 6 -12 volt primary, 500 volts, 90 watt secondary. live maybe, in Oklahoma City about This little ten watt set can easily be constructed for less than $100. ten, twelve years ago ?" Sometimes it Requires a minimum of technical knowledge to effectively operate. is a different Sophie, but just as often it is then KFI is This but one of over 200 combinations listed the right one and in Bulletin No. 237B. oranges or a pair of Write for copy today. thanked with a box of your bed -room slippers orsomethingof the kind. ELECTRIC SPECIALTY COMPANY The hostess at KFI, who happens to be the writer of this story, is con- TRADE "ESCO" MARK vinced that the perfect hostess at a station should have an 207 ,South Street. Stamford, Conn. broadcasting Encyclopaedia Britannica and a reference 4 library at her elbow to be able to take care of the various questions that are asked on anv one night. STATEMENT OF THE OWNERSHIP MANAGEMENT, CIRCULATION, ETC., REQUIRED BY Free Subscriptions THE ACT OF CONGRESS OF AUGUST 24, 1912. Of Radio Age. published monthly at Mount Morris. Illinois, for April 1, 1925. ! State of Illinois. County of Cook, as. for Your Time Before me. a Notary Public in and for the State and county aforesaid, personally appeared M. B. Smith. who. having been duly sworn according to law, depmes and says that be is the RADIO AGE, Inc., will give a year's free sub- Business Manager of Radio Age and that the following is, to the bast of bis knowledge and belief, a true statement of the ownership. nagement (and, if a daily paper, the circula- scription to this magazine to any reader who will tion), etc., ofthe aforesaid publication for the date shown in the abo caption, requited by the Act of August 24, 1912. obtain for us a news- dealer who will handle our embodied in section 443. Postal Laws and Regulations, printed on the reverses of this form, to-wit: magazine in town or city where we al- 1. That them and addresses of the publisher. editor. a are not managing editor, and business m -nagen are: Publisher , Radio Age. Inc., C'bicago,mIll.; Editor, Frederick Smith. ready represented. Chicago. Ill.; Managing Editor Frederick Smith, Chicago. Ill.; Business Manager, M. B. Smith, Chicago, Ill. 2. That the owner ist (If the publication is wned by an If you are now a subscriber to RADIO AGE, individual, bi. name and address, or if owned by more than one individual, the name and address of each. should be given we suggest that you refer this notice to one of your below; if the publication is owned by a corporation the name of the corporation and then and address of the stock- friends who will doubtless be pleased ad- holders owning or bolding one per cent or of the total to take amount of stock should be given). Radio Age, Inc.. Chicago, Pl.. Frederick Smith. 500 N. Dearborn St.. Chicago. Ill.. vantage of this opportunity. Or you may extend President: M. B. Smitb. Secretary and Treasurer. 500 N. Dearborn St., Chicago. Ill.; John H. Lobheck. Vice -President your own subscription for one year without cost. 6429 Cateo Ave., St. Louis, Alo. 3. That the known bondholders. mortgagees. and other M IY IN MM e se e11111= e e eINII e a e eMIN1110 e eM _. e'e t e! s s security holden owning or bolding 1 per cent or more of total amount of bonds, mortgages, or other securities are: (H theree o so state). None. r Free Blank 4. That the two paragrapbs next above giving the lumen Subscription the owners, d if ny, of security holden. RADIO AGE, Inc., contain not only the list of stockholders and security holden 500 as they appear upon the books of the company, but also, in N. Dearborn Street, eases where the stockholder or security bolder appears upon Chicago, Ill. the (woks of the company as trustee or in ens other fiduciary Gentlemen: In order to get a free subscription to RADIO AGE. "The Magazine with Blue- relation. the name of the person or rporation for whom I name a such trustee is acting, is given; also that toe said two para- prints," for one year, herewith send you the of dealer a ho will sell RADIO AGE in the graphs contain statements embracing afants full knowledge city mentioned. It is understood that if you already have a dealer in this city that the offer of and belief as to the circumstances and conditions under which a free subscription does not hold good. stockholders and security holden who do not appear upon the books of the company as trustees, bold stock and securi- Dealer's name ties in a capacity other than that of e. bona fide owner; and this affiant bas no reason to he.ieve that any person, associa- tion. or corporation has any interest direct o indirect. in Street Number the said stock, bonds. or otber securities tban r sa so stated by him. City State 5. That the average number of copies of each issue of this publication sold or distributed. through the mails or other My name wise to ;mid .subscriber during the six months preceding the date shown above is: (This information is required from daily publications only). Street Number M. B. SMITH. Business Manager. City State Sworn to and subscribed before me this 1st day of April. 4-25 19M. FLORENCE A. SMITH. (My commission expires Sept. 21, 1926). * Tested and Approved by RADIO AGE RADIO AGE for May, 1923 The Magazine of the Hour 55 WNAC -The Popular Women's Station (Continued from page 25) prophesied the future in hatdom. And it all be remembered this show was ilverNacsRADIO EQUIPMENT INC. must that the real thing; in other words, inside stuff. Only milliners were allowed admittance, even though any American house -wife could hear the entire proceedings. SILVER CIRCUIT DESIGNS As the many beautiful models came Have gained recognized supremacy for the SILVER 7 -TUBE SUPERS and the SILVER 4 -TUBE RECEIVERS. Sets built down the run -way to the music of one according to Silver Circuit Designs have been approved by the of Boston's smart orchestras, Jean Sargent "WHO'S WHO" of Radio - . . have been lauded by thousands of successful builders as the most wonderful receivers for distance and gave a remarkable word picture of each. loud speaker miles. . . They have outperformed every promise describing the gowns in careful detail. and claim made for them, and have secured results no other set or design could offer. And the men did not regret listening in on this colorful feature -even if the color Silver Circuit Designs, by McMurdo Silver, Assoc., I. R. E., who is unsurpassed in Radio design work, are complete, explicit and could only be seen by proxy. For when easily followed. Complete construction calls for just three tools. one heard the announcer say: "And here You cannot build better or surer than according to Silver Circuit Designs. You will find it easy to build the Silver way, and you will comes a very beautiful girl with a stright- have a set that is years ahead with the finest of Radio Reception - line gown of lip -stick hue, wearing a a set that will be up -to -date for years to come. directoire hat of dull garnet satin," or, McMURDO SILVER Your order for any of Mr. Silver's designs will be filled by SILVER- Assoc. I. R. E. MARSHALL, Inc., without delay. "There is a cute little blonde- haired lady making her entrance as the orchestra plays 'Blue -Eyed Sally;' she is wearing a gown of blue charmeuse edged with old Designs That Are Dependable silver and her hat is one of the new large Blueprints and Complete Building Instructions for the Silver Super__25c designs in color to match; very chic!' The Book -"THE PORTABLE SUPER -HETERODYNE Whose imagination would not flutter after Complete Building Instructions for the Silver 4 -Tube Receiver_____25c all that vivid description? This millinery show was referred to Mail Your Order Today above as the crowning triumph of the women's section of \VNAC, but anyone S -M TWO -TENS The Curve who knows Jean Sargent knows that she Tells will not be content to rest upon her AND TWO ELEVENS the Story laurels. Take for instance, this statement LONG -WAVE TRANSFORMERS made several weeks before the millinery MATCHED -TESTED CHARTED show, in the home -like atmosphere of one - S-M TRANSFORMERS unquestionably rep- of the station studios: resent the most important achievement in Radio "Within the next few months," she for years. . So uniform are they that each instrument can be tagged with its individual said, "I am planning to give the women amplification curve ... another S -M Idea that more and more; for, after all, the women demonstates again that McMurdo Silver's en- gineering methods are always a year ahead of are becoming just as ardent in this radio the industry. game as the men. For instance, after on a special program of any S -M Transformers are supplied in sets of two, or three putting TWO- TENS (iron -core interatage), and one TWO - variety, we usually find women to be ELEVEN (filter for input or output), with identical peaks men. A woman is and separate curves. Each curve is plotted in our labora- more responsive than tory and recorded directly on the tag tied to the trans- quicker to critise than a man, and criti- former. Both peak at 5000 meters and pass an 11 first - kilocycle sideband without distortion. cism is essential in the life of any Price of either type_ _EACH 58.00 class radio station." WNAC is a progressive station, and Today For its sponsor, John Shepard, Jr., is an idol F REE ' "THEWrite WHY OF SILVER CIRCUITS" in many of the hearts of New England radio fans. Frequently, the programs for women are relayed from the Boston sta- Eastern Dist. tion through the Providence station of 20th Century Radio Corp., Silver- Marshall f Inc. 102 Flatbush Ave., the same company, \VEAN. Brooklyn, N. Y. 110 S. Wabash Ave., Chicago And as the genial and highly popular director of \VNAC, Major John J. Fan- ning, says: '\V' in both cases "The CRESCENT LAVITE RESISTANCES might stand for 'woman'." 12,000 Absolutely non-iaducrive e Standard 48,000 LIST 50,000 Si so of' the World- 100,000 EACH Ohms STATIC-THE RADIO N 11i.> BUGBEAR [(y I ' CwIS ;:re -' Sr ,s el reestsacrs to order, 82.50. When Letter resistances How can it be best elimi- * are made they bear the Crescent labsI ,Ni . r¡"" 'l^m CRESCENT RADIO SUPPLY CO. nated, or at least minimized to Liberty Street Jamaica, N. Y. an unnoticeable degree? Ros- The base -type Freshman Variable Grid Leak coe Bundy, that famous radio is the standard for those who build their prepared an article own sets. It is the most compact and be- analyst, has ing entirely sealed it always remains un- *CABINETS on "Static" that will do away affected by any climatic conditions. If you are interested in a Complete with either .00025 or e1gin radio cabinet in which is with the old fear of Summer .0005 Freshman Condenser- combined both beauty and without condenser .75 practicability, just reception. Look for it in the At year dealer's, hensi.esevd purchase write price and yen is be súpplied postpaid LAKESIDE SUPPLY CO., June RADIO AGE -out May Dept. R 15th. Chu. Freshman Compsvy. Iva. 73 West Van Buren St. 240.248 CHICAGO, ILL. W.` 40th St N. Y Telephone, Harrison 7840 * Tested and Approved by RADIO AGE * 56 RADIO AGE for May, 1925 The Magazine of the Hour

gtpir;^r. How to Make a Vacuum of the meter (MA), repeating this opera- tion in steps of 5 volts until you cover Tube Tester the desired range. Connect these points (Continued from page 12) on the chart with a line and you will been bolted down as tight as is safely have a plate current chart at a "0" possible. volt grid bias. A poor connection will add resistance To plot a plate curve at various grid to the circuit and may result in throwing voltages, and for positive and negative the readings of the meters off quite a bit. grid biasing, move the switch (BS) to We will now turn to the wiring diagram the positive or negative point and adjust and run the leads as indicated in the the potentiometer (GP) until the desired table on page 11. The panel will then be grid voltage shows on the meter (GM). marked as desired and mounted in its Always cut the meter (GM) out of the cabinet or placed in its permanent loca- circuit by use of the switch (GS) when tion. Simple, isn't it? Only 25 leads to reading the plate current on the meter run. To connect the instrument for (MA). A grid voltage curve for various Finer Selectivity operation, the batteries will be connected plate currents and voltages will be made as follows: in the same manner, except by taking Equip your receiving periodic readings from meter (GM), set with Apex Vernier "B" or Plate Battery say about one -half volt apart and plotting ¡ Dials. They will greatly Connect 90V of "B" grid battery from ' increase the efficiency of the curve the same way. any set. Make tuning pos. binding posts B -to B90,taking taps off at itive -bring in distant sta. Formulas and other data for testing tions.Yourdealerhaethem. 2214 volts, 45 volts and 67 M volts, and and plotting curves will be published 1f not send $2.00forRoyal connecting -them to their respective BrassFinish- $2.5Ofor Sat. in an early issue of RADIO AGE, with in SilverFinieh.or$3.50for binding posts B 22 M, 1345 and B 67 M. a view to covering as much -about tube DeLuxe Gold Plated (24k). "A" or Filament Battery characteristics as is useful to the fan. APEX SUPER 5 Connect a 1%, 3 or 6 volt battery Tables for average computation will This highly efficient ; across binding posts A- and A+, the also be shown. Ìtunedradio frequency size to be according to the tube under receiver is most advanced indesign and construction. test. An instrument that meets every critical expectation "C" or Grid Battery of the radio enthusiast. Connect two 43á VoltCbatteriesin series Pickups Housedinahighlyfinisbed, walnut cabinet. complete and across binding posts C+ and C -, with Jones Multi plug Bat. taking a tap between the two batteries By Our Readers tery Cable. All settings highly gold plated. Sells for and connect it to binding post C± -. (Continued from page 44) 595 complete excepting accessorlcs. Method of Operation circuit used by Mr. Miller, which is a At AU Good Dealers TO TEST a tube or plot a curve, variation of the three circuit principle. APEX ELEC. MFG. CO. there are several characteristics about Any of you who are interested might 1410 W. 59th St. Chicago ¡J drop him a line and get the desired in- Dept Sll a tube that can be put to good use, formation direct from him. Anyway, when known. They can be found by we are going to award him a DT degree using this tube tester. Let us take a for the splendid results he is having as Number 199 type tube and plot a grid a result of exhaustive experiment. potential and plate current curve, foi example. When the batteries are all connected, RADIO AGE, put the tube into the socket (T) using Gentlemen: the adapter. First move the switch I am a reader of RADIO AGE and I (BS) to the negative point, then move have learned many a thing from your the switch PS to the 45 volt tap. Now magazine. I know the fans are after set the transfer switch (TS) for the circuits that are simple and powerful and this sure will bring in DX as clear Illlf 111! volt scale on the (PF.) Move ,I 0 -10 meter as a bell. This is Capacity Feed back the rheostat (R) until the meter shows IF, .i mn circuit and here is a record of DX Satur- 3 volts. day evening from 10 p. m. until 12 mid- Adjust the potentiometer (GP) until night at my friend's home in Woodhaven, the meter (GM) shows "O." Now L. I., Jerome Kupfer, 8411 94th Street. throw the transfer switch (TS) for the KDKA, KYW, KFI, WSAI, KSD, 0 -100 scale on meter (PF), and adjust PWX, HAVANA, WHAS, WOO, WIP, the rheostat (BR) until a 45 volt reading WTAM, WGAM, W\ \rJ, \VGR, and is obtained. Then cut out meter (GM) W REO. r7liec?raftic Cop by use of the switch (GS) and move These were all heard on a loud speaker (R) until the highest all over the house and clear. If any of the resistance something better, of the lir is obtained on the milliammeter you fans can show me reading well, go to it, boys, I am on the job to Make your Bet selective-separate (MA). This will be the normal plate the interfering bkeepie learn any time. If you will write to me stations by simply of the tube, at 45 volts on the Putting the Traffic Cop on guard. Gentlemen: current I will gladly join you working out cir- The Ferbend Wave Trap will tune The Wave plate with a grid bias of "0" volts, and with my favorite RADIO AGE out interfering stations, no matter Trap ordered cuits how troublesome. Never reduces, from you whatever filament voltage the meter Magazine. but nearly sometime always increases volume. ago is all that (PF) will show. Yours very truly, Add a Ferbend Wave Trap to your you claim for William Bentner. set and police' your reception. it and then To plot a plate current curve (See Regulate the traffic! some. 3 and 4), move your switch 304 Park Ave., Designed and manufactured com- It not only Figures plete by us keeps out the 2214 volt tap and adjust Brooklyn, N. Y. after years of careful ex- other station (PS) to the perimenting. It is not to be con- that is caus- your resistance (BR) until the volt- Here is a good offer, fellows. Any of fused with imitations, hastily as- ing the inter- want information on circuits sembled from ordinaryparts. Price ference. but meter (PF) reads 20 volts. Adjust the you who is $8.60. Shipment is made Parcel it also seems of this type should get in touch with Post C. O to act as a filament rheostat (R) until the maximum D. plus postage. or post- clarifier of "Bill." The circuit he describes we are paid on receipt of price. Order today. the incoming reading is obtained on the milliammeter unable to print this month, but will use CO. station. as shown on 1.6 E. SóWater StELECTRI Ch Ill. (Signed and spot this reading the it in the near future. It must be very Send for FREE Booklet W. E. Wiltse. chart. Now adjust your switch (PS) efficient, judging from his DX log and TERSE, . and your rheostat (BR) until the meter the offer he makes. mlr// //r¡ sue.17lt.- ,_ (PF) shows 25 volts, and spot the reading (Turn to next page) g Tested and Approved by RADIO AGE RADIO AGE for May, 1925 The Magazine of the Hour 57 RADIO AGE, Inc., Chicago, Ill. Dear Sirs: Herewith find list of broadcasting stations picked up on a one tube radio set on the evening of February 21, 1925. I hope that this will entitle me to become a Dial Twister and in anticipa- tion of receiving your button by return mail, I remain, Yours very truly, Ntcholas G. Hart. Bienville, Levis, P. Q. Here is his list, and we think it is one of the best ever submitted to these columns, considering distance. I{YW, CKAC, WREO. WEAF. WEBE, WON, WTAM WSAI. WBZ. WGY. EDNA. WCAL, WLW. W IAS. WOA. WFBH. CFCA. CNRO. As "Sen" Raney of KYW would say, "Yes Sir, Yes Sir," indeed, you do get Better Than a your D. T. button. Laboratory Standard RADIO AGE, Gentlemen: The usual method of measuring condenser resistances is by I am sending a list of stations that I received on a two tube home made comparison of readings obtained when the condenser to be meas- Harkness. I am located a half a square ured is interchanged with a precision, laboratory "standard" from a transforming electric station and in the same circuit. have a lot of interference. I hope that this list entitles me to a DIAL T \\'IST- Professor G. M. Wilcox, of Armour Institute of Technology, ER'S button. recently conducted tests on two B -T Lifetime Condensers taken EYE, EDNA. EFNF, EPOS. ICED M. EFLC. EFES. from stock and found they were of lower resistance than his EFES, E$D, PWX. WJY. WBZ. WLW, WSAI. WCAP. WMH, WDAF, WGY, I,TAM, WHAZ WJAR. WCBD. laboratory standard. KEEL WON, WEBS. WOR. WEN. WEAS, WAIL WOC. WEAF. WEBE. WOS. WJAX. WBAY. WREO. WO/. WCCO. WTAS, WOR, WJJD. WLS, WOAW. WWJ. WHO. Part of Professor Wilcox's letter reads as follows: WSIAZ. WFAA, WEB. WOO. WHA. WNW. WEAN WJAS. WCO,B WNAC, WSBI, WAHO, 51íA\£, WOAD, YGAN. WEAL, WOAL WOI. WBCN, WIAD. WDAR. "When the B -T Condensers were in the circuit the current WBBR, WBBL, WEE. WTC, WCBR, WWAE, WTAY.CK EOP. was 1 to 2 per cent greater than that obtained with the Labo- Yours very truly, ratory Standard." Robert Drake. Condensers, 23 East Spruce St., "Better than Laboratory Standard," are repre- Elmwood Place, Ohio. sentative of the efficiency of B -T products generally. This is a very fine DX list, and we are Such apparatus in combination with a specially designed sure that you will agree with us in award- circuit made possible the B -T "NAMELESS," ing Bob his D. T. Button. He must now known have sat up "plenty" nights to get such nation wide for its selectivity and range. a fine record together. The new 7th edition of "Better Tuning " describes the "Nameless," including 48 pages of hook -ups and helps of value to any radio fan. At your dealer's or by mail on receipt of 10 cents. WARM - WEATHER SUR- PRISES FOR RADIO ETTER AGE FANS! TUNING As warm weather and Summer D REMER 1 ULLY MFG. CO. approach, there will be no let -up in interest in RADIO AGE's 532 S. monthly articles. In the June Canal Street. Chicago number, on the stands May 15, there will be countless agreeable surprises, among which will be: "Outdoors with Radio," by Arm- strong Perry. "Getting Rid of Static," by Roscoe Bundy. "A Portable Super -Heterodyne," HUDSON-ROSS``` RADIO CONSOLE by H. Sills only 'Guaranteed:: Frank Hopkins. FGM. CO. 562 VEDDER ST. The Browning -Drake Circuit. Radio Apparatus: RAULF Grid Send for, discounts. More About the Double CHICAGO. WRITE FOR CIRCULAR Tube and Its Circuits. W. Madison St Chicago How to Make This a Radio 123 Summer. A Big Pickups Section And Many Other Features.- Order your JUNE RADIO AGE audio frequency transform- Now! FI..IIVT ers for all hookups @@ 50 Mailing Lists and types of tubes. W Sea. Will 6 1p }}++ou increme sale Q Economy price, Send for FREE falog of and and prices on eimvfied perfect operation insured. éoossadd.eeoff Moneyback if not satisfied. a ro-.Iatlonal,Sufea,Seess rid - Q If your dealer cannot 99P fessions, Itle Cooew.. Don't forget to send your DX supply, order direct. rGuaranteped ,0 byrefond f 5 each lists to- FLINT RADIO CO. THE PICKUPS EDITOR 1864 Wöses Are.. Chicago, Ill. it Tested and Approved by RADIO AGE 58 RADIO AGE for May, 1925 The Magazine of the Hour Get Cuba Maximum Miles Per Watt or with Mexico City This Transmitter

While Big Local Stations Are Broadcasting. The New York Eve - ning World got 46 stations in One Evenino. including Dallas, Los Angeles, and Porto Rico while testing the wonderful sensitivity of the New In Principle -New In Design WERNER Radio Frequency TRANSFORMERS o For All Circuits f! The success of a really selective receiver depends on highly aensitiva W RNER TRANSFORMERS. Insist on getting them, if your dealer can't supply you, send your order to us. Price $4.00, All Types Send for Diagrams A wonderful interesting book "Radio New fregaencyAnplifirntion" contains pop- Diagram ular and technical information with many up-to -date R. F. circuit dia- Leaflet grams of greatest interest to both Sent radio user and engineer. FREE 25c postpaid. An Esco Item No. 33 Motor Generator is employed as the source of power in this trans- Co. mitter of the 30 -wall type. A R. Werner Radio Mfg. transmitter like this empolys 204 -20$ Ninth St. Brooklyn, N. Y. the well -known 3-coil Meissner MO- circuit and gives remarkable NM\ distance for its sise. Make 5100 Weekly -sell RADIO Demonstrate Onee- Results Mean Sore Sale TO THE man who has a limited condenser for audio frequency, the radio Coast to coast,lowest prices,attrac- amount of capital to invest and wants frequency by -pass condenser C6 should tive four -tube instrument $39.50. to obtain the maximum miles per dollar, not be larger than .01 tnfd. Big commission to you. Exclusive which is essentially territory to proven salesmen. Ter the maximum miles Meters. Upon the intelligent use of ritory going fast, write today for per watt, this efficient little set should the meters depends the efficiency of the arge illustrated book No. 100. appeal. The set is a 20 watt trans- set. A properly operated set will work Don't fail to name your county. mitter using 4 -5 watt tubes. By means rings around an improperly operated hi gtA Inc. 1329 wa Blvd. licago. III. of a double throw, double pole switch, set of much larger power. The plate the set may be used for either phone or milliammeter should be of 0 -300 milli- continuous wave telegraphy. The cir- ampere capacity. The filament volt- cuit is the well -known three coil Meissner. meter from 0 -12 volts. The antenna Power Supply. Telephony has today ammeter should be of the thermocouple reached such a state of development type from 0-3 amperes. The above that not only must the voice be carried meters are essential to the practical in an intelligent manner, but it must operation of the set. Two additional be a true reproduction of the original, meters will be of great help. A plate free from distortion and unaccompanied voltmeter of from 0 -600 volts and an by stray noises and hums. The "pure additional thermocouple meter to put wave" is also an important factor in in the antenna circuit. With an ammeter telegraphy efficiency and the reduction in the antenna lead and one in the BlgMoney-Saving RadloCatalog of interference. The nearest practical counterpoise lead, it will be impossible containing a thousand bargains of every - thing in radio; perm aupphee. com- approach to this "pure wave ' is the to obtain a balanced condition with a plete parts for sets.eompleteseta. etc.. also a mine of very IM- current delivered by a properly designed resulting greater efficiency. Oest intonation on all dit motor generator set. From the view- General. The three coils may be t «rent circuits,, complete list of g and point of good telephony, efficiency, of either the helix or pan -cake type. ;dill, valuable data.[ions flexibility and convenience, "Esco" The hinged pan -cake type is to be pre- i. -`t Easy ea build your awn radio an set. All complete parts of acts Item No. 33 has been chosen as the ferred, as the coupling may be easily . Glpt of standard adv.rtleed guaranteed parts and include source of power supply. This type is a varied and part turn taps are more drilled 5.Nellte panels and wlr- four bearing two unit set. The gen- easily effected. The aerial and counter- Ing dlegrems for easy assembling. Everything nent erator is of the double poise condensers should be of the trans - b.,I. Servir.nOeptet-hent commutator tely. vow ..d.. uIl .our maw emblem, type, supplying 100 watts at 10 volts mitting type, capable of withstanding Send name address for free cata- for the filaments 200 500 frequency of high voltage. The og. en names of friends: we will mail them catalogs. and watts at radio RANOOLPN C44R4 OR4r10N volts for the plates. Regulation of the use of two is not essential if a balanced ia9 North Union RAOOept CHICAGO output power is obtained by means of condition is not sought. The usual a rheostat in the field of the generator. condensers across the grid and plate Filter. The filter is the conventional coils have been omitted. While they are Radio is going to take tre- three section "pi" type. The induc- a slight aid in tuning, they constitute mendous strides during the tances should all be equal and from 10 a constant loss and often cause the to 30 funda- few henries each. The condensers radiation of other waves than the next months. The up -to- should be from 2 to 4 henries each. The mental. Keying is accomplished by date radio fan cannot afford to rules for combining filter sections should means of a relay which may easily be lose interest during the warm be strictly adhered to; i. e., C1 equals made from a telegraph sounder. As months if he expects to be C6, and Ca equals Ca, and under all this relay is in the grid circuit, it should conditions C1 equals one half C. Were be mounted as near the tubes as possible, acquainted with the newest it not for the use of telephone, the and be connected with short leads. developments next Fall. A .modulation choke could be omitted. Both the relay and the current through subscription to RADIO AGE, The omission of this choke would permit the modulating transformer are con- at $2.50 a year, postpaid, will the large condensers of the filter system trolled from jacks on the panel. A to by -pass the modulating frequencies small knife switch should be used to insure your being constantly and all attempt at telephony would shunt the relay when telephony is being informed of the latest in the result in an unintelligible gurgle. A used. A 4 -8 volt battery should be used ethereal art. DO IT NOW. five to ten henry choke will be sufficient. for modulation and may also be used to Due to the by -pass effect of the larger operate the relay. RADIO AGE for May, 1925 The Magazine of the Hour 59 International Radio Problems Come to Fore VVASHINGTON, D. C.-With the passage of the bill carrying the State Department's budget of $75,000, plans for the International Radio Con- ference to be held here in September are being formulated. The actual agenda depends somewhat upon what action the world telegraph conference at Paris takes this Summer. The United States will not be officially represented as it is not a party to the conventions. A careful study of the action taken there, especially with reference to the attitude of the World Powers, will be made by American Governmental officials and up your set radio experts, in order that the general trend of opinion on electrical communica- with good tubes tions may be followed. It may be found more practical to eliminate discussion on strictly technical matters, such as specific wave channels, uT didn't think that tubes power limitation and such matters, as made such a difference they might tie up development in a until I changed to MAG- mass of technicalities, which could not NATRONS." That's what be changed for three or four years. one enthusiastic MAGNA - The essentials of world -wide radio TRON user wrote us. communication will be covered in the Paris Conference, since they are in- corporated under the clause of the old You, too, will be pleasantly telegraph convention of 1908, covering surprised by the way that ship -to-shore radio communication. It MAGNATRONS "pep" up is believed that the Paris conference will a set and give it a new lease extend these regulations to cover trans- on life. The many improve- oceanic radio services. If this is the ments which have been case, radio service in general, licenses, made in MAGNATRONS classification of messages, accounts and have placed them in the very rates may be outlined at Paris prior front rank of vacuum tubes. to the American conference. It is quite probable that a broader conception may be placed upon the old MAGNA TRON DC -199, plan for allocating high-power com- DC -201A, and DC -199 with mercial stations throughout the world. large base sell for only $3 Advanced thinkers on this subject believe each at your dealer's. that the location of commercial stations within the boundaries of a country is a matter for the particular country to Manufactured by determine. The international allocation CONNEWAY ELECTRIC LABORATORIES of signals, such as distress and general 309 Fifth Ave., New York City calls, as well as the assignment of high - Paefories. Hoboken, N. J powered station call letters, will be dis- c ussed, although it is believed that this matter will continue to be handled by the central bureau at Berne. Inter- national broadcasting by amateurs may be considered, as recently the amateur I has come into world prominence, and his call letters, although national, have no definite significance in another foreign country, and may be duplicated. As most of the countries of the world are parties to either the telegraph or Log for Your Radio the radio conventions, it is likely NEW 64 papa log. Bolds 400 etatleue. HUDSON -ROSS that calla, eiaee, wave lengths. 4 dial vet. flowsShows k.. te. TUNING SUGGES. more than fifty separate governments _ T101í5.Swtioo Wt bs wave lenity -bv Largest exclusive Radio I states etc. Owners. Map. TRDUBLEAID5. will send delegates to the United States +} Othervaluable ,vforaatov. So eevveoreot. Worth Jobbersin middle West. this fall to participate in the delibera- De Luselulthee ewer. OnOnly yFi. Write for discounts. F°rapli tions on radio regulations. Send No Money Y moe it rsec: FUNDED II net DELIGHTED. Ord today -NOW. Po,tal will do 123 W. Madison St Chicago The 1920 Conference RADIO PRINTERS. Dept. 9025 Mendota, 1111note In October, 1920, about a year before America in general became vitally in- WHOEVER HEARD OF BAKING IN A POT. terested in radio, a preliminary radio woman BAKELITE SOCKETS conference was held in Washington, Ask the who owns a "Master Bake Aid g. where representatives of Great Britain, clear reception. Pot- or request us for Write for Booklet 31 France, Japan and Italy met to draw Free story of this re- up an outline program for future dis- markable invention. BAKELITE CORPORATION cussion. Most of the visiting delegation 247 Park Avenue, New York, N. Y. Cadmus Products Co. 00 Chicago Office: 636 West 22d Street were headed by the respective am- BAYONNE, N.J. also Loado., Eq. $ Tested and Approved by RADIO AGE 60 RADIO AGE for May, 1925 The Magazine of the Hour bassadors and ministers, and the United Europeans Seek Protection States was represented by Under Secre- tary of State Davis, Postmaster General for Radio News Burleson, Admiral Benson of the Shipping RECOGNIZING radio as a modern Board and Walter Rogers. means of transmitting news, the The conferees laid down proposals members of about twenty -five press under the following subdivisions: The associations in Europe have taken steps radio protocol of the Peace Conference; to protect their property when it is en a universal communication union, com- route through the air. Resolutions posed of telegraph and a radio sections; signed by such well -known news agencies International telegraph, radio and cable as Havas of France, Continental of i `The Famous Truly Portable laws; and improvements in the com- Germany, Fabra of Spain, Reuters of munication facilities between the five Great Britain, Stefani of Italy and TELMACO Pea Receiver great Powers. Rosta of Russia have been filed with Four Tubes Do the Work of 7 The British submitted a plan for the the International Telegraphic Union Coast-to -coast reception. Aerial, loud speaker, and batteries self -contained. Carry from room to room - amalgamation of all electrical com- at Berne. Other suggestions will be take it anywhere. Size 8'x 17x 18'. Total weight only munication rules and regulations to be submitted to the International Conven- 261bs. Complete with tubes and batteries, $125 00 8143.50. Receiver only . . . . submitted to a world's congress on corn - tion for the Protection of Industrial P.1 Kit Saves You Money! munications, which, however, never ma- Property, which meets at the Hague in In resporee to a popular demand we now offer the Telmaco P -1 Receiver in kit form. This contains all terialized. October. parts, as built by us, including case, drilled and en- The old international code system, a What amounts to radio censorship is graved panel, and illustrated instructions. Complete kit $80.00 method of communicating between sta- suggested, broadcast transmission would Ask your dealer or write us. Descriptive folder free. tions or ships of different nations, was be controlled, receiving sets limited and 'Radio'Division: pronounced out of date and not adapted many phases of radio operation definitely Telephone Maintenance Co. for radio. Provision for transmitting regulated, if the plan is carried out 20 So. Wells St. Dep??t.,, C, Chicago. 111. messages intelligible to all operators, internationally. regardless of the language they spoke, Essentially, the foreign press associa- atality'$adio Exclusively 'd Established 1918 was planned for use in sea and aerial tions insist on ethereal property rights, navigation; covering damages, sickness, patent protection, and punishment when stores, fuel, meteorology, ship and air- their copy is picked up and used with- craft business, and other special needs. out permission. They recommend that Although the State Department has a technical means which will prevent the TRY US! made no official move toward calling the reception and use by unauthorized nations of the world to this conference, persons of press matter transmitted by RADIO DEALERS! it is understood that formal invitations radio, be developed. Simple methods will soon be sent out, and the working of ciphering and deciphering, insuring We are exclusive up of a program begun. rapidity of handling, have been devised, Radio Jobbers and partially secret radio apparatus and DO NOT "What is Radio ?" has been perfected but not adopted "Wish I knew something about radio generally. In Europe the governments RETAIL. not the technical part, you know, just- control and operate radio as they do enough to understand what it's all about." practically all communication systems; Howard - Crosley Yes, and the people you hear say this therefore, it might be a practical possi- Liberty- Day -Fan are only a small part of the thousands bility. But in the United States, where who think it. private companies handle communica- Receiving Sets Lack of knowledge and consequent diffidence or uncertainty are the greatest tions, great difficulties would be en- Complete line of parts. handicaps of the radio industry today. countered in this connection. We Sell to Dealers Only. Untold thousands of people are not buy- It was also recommended that national Write for Catalog. ing radio sets simply because they are governments agree not to authorize the afraid. They don't know. establishment or maintenance of any TAY SALES CO. It is to meet this need that the makers private radio receiving stations until N. Franklin St., Chicago of the Somerset radio receivers have pub- the authorities have taken all precautions 6 lished a unique booklet for beginners- the Somerset Radio Primer, "a little to strictly limit the capacity of the re- book for the man who knows nothing ceiving set. That is, receivers would about radio," telling him what radio is, be constructed or set so as to pick up and how to choose a radio receiver. only matter broadcast on certain wave It is written for people who are not bands and not on those channels carry- familiar with electrical or mechanical ing news. This sealing of sets has been terms and principles but who would like attempted in some countries unsuccess- to know the general idea for radio recep- fully, and certainly would be a tre- tion. Leaving out the technicalities and re- mendous undertaking in the United finements, it tells the story briefly, clearly States with several million unlicensed I offer a comprehensive, expe- and interestingly. Difficult points are receiving sets to locate and adjust, even rienced efficient service for his a law. prompt, legal protection and the explained by analogy with familiar ob- if it became development of his proposition. jects. Ban Asked Send sketch of model and descrip- For example, the action of a rheostat Strong tion, for advice as to cost, search through prior United States patents, is compared with that of an ordinary Positive legislation against violation etc. Preliminary advice gladly faucet in its control of the following of secrecy and illicit use of press matter furnished without charge. stream of water. As penalties for use My experience and familiarity showing is urged. the of with various arts frequently enable There are many illustrations unauthorized radio news, these organ- me to accurately advise clients as the principal parts of radioreceiving out- to probable patentability before fits, with a brief description of each part. izations desire imprisonment, confisca- they go to any expense. The Somerset Radio Primer has tion and damages, as well as forfeiture Booklet of valuable information and caused enthusiastic approval wherever of licenses, if illicit use is proven. form for properly disclosing your shown. The Primer is Intended for dis- Reduced telegraph rates for press idea free on request. Write today. tribution by Somerset dealers and is matter are asked, and assurance that furnished with the dealer's name im- messages will go forward at RICHARD B. OWEN, Patent Lawyer may delayed 81 Owen Bldg., Washington, D. C. printed on the cover. Sample copies lapse of press rates, despite the of time 2278 -M Woolworth Bldg., N.Y. City be had by writing direct to the makers for rates to apply. Somerset receivers, the National Air - fixed press phone Corporation, 22 Hudson St., Further, the signatories ask that if New York. broadcast concessions are made, the con- b Tested and Approved by RADIO AGE RADIO AGE for May, 1925 The Magazine of the Hour 61 cessionaires be required not to send out political, commercial, financial or other news except that which is submitted and filed by recognized news agencies. This is a curious reversal of the situation in the United States, where the Asso- ciated Press has refused to permit its news items to be broadcast. The prop- erty value of press news has never been established internationally, it is Fointed out, except that in some instances pro- tection after publication is afforded, which would not benefit the news collect- ing and distributing agencies. In other countries, cnly what are considered literary works are protected by law. The members of the foreign press associations claim that radio broad- casting is a menace to them as well as to the public, on account of "the ease thereby given to the spread of uncon- trolled news." How these suggestions will affect the news associations and the private com- munication companies in this country, as well as the broadcasters and listeners, is unknown, but as American repre- sentatives will be present at the con- Reliatbility ferences, it is assumed that all interests will be protected in the event inter- national agreements are drawn up. THAT trait of thoroughness which merits confidence is always met with high regard. For there is deep satisfaction in knowing that the task in hand is being done as well as it is possible to do it. Market for Tapped "B" Batteries Falling Off This appreciation for reliability has established the leadership The waning popularity of the "soft" enjoyed by Jefferson Transformers. Sheer quality and perfor- tube has greatly reduced the demand for mance have won the favor of unbiased radio authorities the world tapped "B" batteries, according to manu- over. facturers of dry cells for plate current supply. Full, rounded amplification over the entire musical range Until the development of satisfactory -a methods of radio frequency amplifica- constant delight to radio listeners. Such splendid performance is tion, sensitiveness in the detector was a the result of 20 years' specialization in the manufacture of trans- highly important requirement for long formers. Replace the transformers now in your set with genuine distance reception. The Freat disad- Jeffersons and see how your set will improve. vantage of the "soft" tube is the precise adjustment of plate and filament voltage which is required to operate it at the most Jefferson Electric Mfg. Co. sensitive point. Very few users of "soft" tubes, on account of this difficulty, ever 507 South Green St. CHICAGO secure the added sensitiveness which it gives only under the most favorable Manufacturers of: Radio Transformers Jump Spark -Make and Furnace and Oil Burner circumstances. Bell Ringing Transformers Break Coils Transformers The problem is further Sign Lighting Trans- Auto Transformers Boil Burner Ignition Cods adjustment formers Testing Instrument. Special High and Low Vol. complicated by the fact that the most Automobile Ignition Coils Toy Transformers tage Transformers sensitive combination of plate and fila- ment voltage, once found, does not re- main fixed. Sometimes a new adjust- ment in order to "hold" a distant station is required in the midst of a program. The more modern types of high vacuum tubes, utilizing but a fourth of the fila- ment current required by "soft" tubes, give as good results as those obtained with the "soft" detector tube, for sets using Index Your Radio radio frequency amplification. Dealers selling tubes perform a service All the 720 Broaden -sung customers if they make sure that Stations of North Amer to their a indexed by Wsys the type passed over the counter is best lengths, Dial Readings. es and ,adapted to the use for which it is Call Letters. Nothing to write intended. In any receiver employing but your dial settings. Gives diarpontions for stations you radio frequency amplification, the saving C>lreKey hay been unable to set. Self- in filament current and the availability indexing. 96 pages, 7:10 inches, witbb tifnllyb u d of more compact and more economical Q0 720 cover, 50e postpaid. Stamp. "B" batteries, make it advisable to taken . recommend high vacuum tubes instead Std2ions The Radex Press of the obsolescent "soft" detector tube. 224 Euclid Arcade Anne: 5O9 Cleveland. O. We Equip You IS IT JAZZ? POST PAIO To be a Federal Radio Dealer and guarantee your success under the "Gould Plàn" which allows you to It isl Anything you hear on RADIO return merchandise which you are unable to sell. AGE'S Congress Carnival from KYW, We sell wholesale to dealers only. Write for our price list and FREE Instructions "HOW TO SELL Chicago on Saturday, May 2, from Have you BOUGHT RADIO." 11:30 p. m. to i a. m., is going to be jazz FEDERAL RADIO CO. and then some. Tune in for a good timel YOUR ANNUAL? 115 East 13th St., Kansas City, Mo. * Tested and Approved by RADIO AGE 62 RADIO AGE for May, 1925 The Magazine of the hour THE RADIO AGE BUYERS' SERVICE What do you want to purchase in the radio line? Let the staff of RADIO AGE save you time and money by sending in the coupon below. Enter the number of the article you would like to know more about in the spaces provided in the coupon. I "A" Batteries 95 Grid leak holders 186 Rheostats, automatic 2 Aerial protector. 96 Grid. transmitting leaks 187 Rheostat., battery 3 Aerial insulator. 97 Grid leak., tube 188 Rheostat., dial 4 Aerials 98 Grid leaks, variable 189 Rheostat., filament FIT FOR A KING 5 Aerial., loop 99 Grinders, electric 190 Rheoauts, potentiometer 6 Amplifier. 100 Ground clamps 191 Rheostats, power Britain's greatest engineers in designing 7 Amplifying units 101 Ground rod. 192 Rheostat., vernier 8 Ammeters 102 Handle., switch 193 Rods, ground receiving equipment for his Majesty 9 "B" batterie. 103 Head bands 194 Rotor. 10 Batteri.. ( Beige) 104 Head phones 195 Scrapers. wire KING GEORGE V. chose Resistance 11 Batterie.. dry cell 105 Head sets 196 Screwdrivers' 12 Betterles. storage 106 Honeycomb coil adapters 197 Screw. Coupled Amplification. None other 13 Battery chargers 107 Hook ups 198 School radio would do. 14 Battery clips 108 Horns, composition 199 Set.. receiving-cabinet 15 Battery plates 109 Home, fibre 200 Set., receiving-crystal 16 Battery substitute. 110 Horns, mache 201 Set., eceiving- knock- 17 Bezels Ill Horn., metal dow THE DAVEN RESISTANCE 18 Binding posts 112 Horn.. wooden 202 Sets. receiving - Neutro- 19 Binding post.. insulated 113 Hydrometers dyne COUPLED SUPER AMPLIFIER 20 Book. 114 Indicators, polarity Set. receiving-portable 21 Boxer, battery 115 Inductances, C. W. 204 Sets, receiving-radio fre- will give to your favorite tuner, that 22 Boxe., grounding 116 Insulation, molded queney 23 Bridges, wheatatone 117 Insulation material 205 Seta. receiving-reflex finesse in quality amplification desired 24 Broadcasting equipment 118 Instil aerial 206 Sets, receiving-regenera- 25 Bushings 119 Insul omposition tive 207 Set., receiving for the Chambers of Buckingham Palace. 26 Buzzers 120 mail , fibre t rtz 208 Seta, receiving- lonal With Resistance the most deli- 27 Cabinet. 121 maul , high voltage Coupling 122 Insulator cloth 209 Seta, receiving-short wave 28 Cabinets. battery 210 Sets, rece iv ing- super -re- cate shadings in musical compositions, 29 Cabinets, loud speaker 123 Insulators, glass generative 30 Carbon.. battery 124 Insulators, hard rubber either with instruments or the voice, arc 125 Insulator porcelain 211 Seta, transmitting 31 Cat whisker. 212 Slate 32 Code practi.ers 126 Iron.. soldering reproduced with a faithfulness not 127 Jack. 213 Shellac 33 Coil,. 214 Sliders obtainable of 34 Coils, choke 128 Filament control with any other method 129 Jars, battery 215 Socket adapter. 35 Coils. coupling 216 Sockets. audio amplification. 36 Coils. filter 130 Keys, transmitting 217 Solder 37 Coil.. grid 131 Knobs 218 Soldering irons, electric Your Dealer will be glad to show you the 38 Coil., honeycomb 132 Knock -down panel unit. 219 Soldering paste 39 Coil., inductance 133 Laboratories, testing 220 Solder flux Super Amplifier which can be attached 40 Coil.. Reinert: 134 Lever. switch 221 Solder salt. a few 41 Coils, stabilizer 135 Lightning arrester. 222 Solder solution to your favorite tuner in but 42 Coil.. tuning 136 Loosecoupler. 223 Spaghetti tubing moments. It costs less to install than 43 Condenser parts 137 Loud speakers 224 Spark coil. 44 Condenser plates 138 Loud speaker units 225 Spark gap. other methods of amplification and adds 45 Conden ,antenna coup- 139 Lug., battery 226 Stamping. ling 140 Lugs. terminal 227 St greatly to the life of your "B" Batteries. 46 Cond . by -p... 141 Meamring instrument. 228 Stop points 47 Condenser coupling 142 Megohm 229 Switch arms 48 Condenser , DAVEN RESISTANCE COUPLED filter 143 M A.C. 230 Switch I 49 Condensers,or en, fined (paper. 144 Meters. D. C. 231 Switch point KITS are put up in three and four stages grid, or phone' 145 Mica 232 Switch stops 50 Cond variable grid 146 Mica sheets 233 Switches, aerial and are for those who would rather 51 Condensers, variable mica 147 Milliamm 234 Switches, battery the com- 52 Condensers, vernier 148 Minerals 235 Switches, filament assemble their own than buy 53 Contact point. 149 Molded insulation 236 Switches, ground plete, ready to attach, Super Amplifier. 54 Contacts, switch 150 Molybdenum 237 Switches, inductance 55 Cord tips 151 Mountings, coil 238 Switches, panel Obtain from your Dealer the RESISTOR 56 Cords, for head sets 152 Mountings, cond 239 Switches, .ingle and dou- 57 Couplers, loose leak ble throw MANUAL, our complete handbook on 58 Couplers, molded 153 Mounting., end 240 Tone wheel. 59 Coupler., vario 154 Mountings, grid leak 241 Tower., aerial Resistance Coupled Amplification. Price 60 Crystal alloy 155 Mountings, honeycomb 242 Transformers, audio fr.. 25c, 35c. 61 Crystal holders a quency Postpaid 62 Crystals, rough 156 Mountings, inductance 243 Transformer filament 63 Crystals, mineral witch 244 Transform modulation 64 Crystal, synthetic 157 Name plate. 245 Transformers. power 65 Crystals, unmounted 158 Neutrodyne set parts 246 Transformers, push -pull 66 Crystal., mounted 159 Nuts 247 Transformer.. radio fre- 67 Desk., radio 160 Oh quency 68 Detector unit. 161 Oscillators 248 Transformer., variable 69 Detectors, crystal 162 Panel cutting and drilling 249 Transmitter* 70 Detectors, fixed crystal 163 Panels, drilled and un- 250 Tubes -peanut 71 Dial, adjusters drilled 251 Tubes, vacuum -two le- 72 Dials, composition 164 Panel., fibre Tut 73 Dials, hard rubber 165 Panels, hard rubber 252 be., vacuum -three The 74 Dials, rheostat 166 Part. ment Aristocrat 75 Dials, metal 167 Paste, soldering 253 Tuner. 76 Dial., vernier 168 Patent attorneys 254 Variocouplers, hard rubber of Amplifiers 77 Dial, with knob. 169 Phone connector., multi- 255 Varioeouplers, molded 78 Dies ple 256 Variocouplers. wooden 79 Drill., electric 170 Phonograph adapters 257 Variometereter. ha d rubber DAVEN RADIO CORPORATION 80 Dry cells 171 Plates, condenser 258 Variometers, molded 81 Earth ground. 172 Plugs, coil 259 Variometers. wooden "Resistor Specialists" 82 Electrolyte 173 Plugs, telephone 260 Varnisnish, nsulating 83 Enamels, battery 174 Poi , dial and knob 261 Voltmeters NEWARK, NEW JERSEY 84 Enamels. metal 175 Poles. aerial 262 Washer. 85 End stops 176 Potentiometers 263 Wave 86 Eyelet. 177 Punching machines 264 Wave trap. 87 Experimental work 178 Reinert. set parts 265 Wire, aerial 88 Fibre sheet, vulcanized 179 Regenerative set part. 266 Wire.lbraided and stranded 89 Filter reactor. 180 Receiver caps 267 Wire. copper 90 Fixture. 181 Rectifier., b 268 Wire, insulated 91 Fuse cut out. 182 Resistance leaks 269 Wire, Litz readers wish to show their 92 Fusee, tube 183 Resistance units 270 Wire. magnet 93 G ttttt to 184 Rheostat bases 271 Wire, platinum approval of RADIO AGE'S 94 Grid choppers. rotary 185 Rheostat strips 272 Wire. tungsten IF stand against the Radio ,s- - . a ------.r -- --, RADIO AGE BUYERS' SERVICE, 500 N. Dearborn St., Chicago, III. Corporation of America, they can I Please see that I am supplied with buying specifications and prlres on the articles numbered herewith: I do it in the most practical way by sending in $2.50 for a year's sub- 1 I I I I I I I I I I I I I I I 1 1 already sub- I am a- -I Dealer Jobber 7 Mfgrs.' Rep. Manufacturer 1 scription or if they are 1 1 scribers, urge a friend to subscribe. 1 Firm [If identified with Radio industry] 1 We believe the fans are with us. My Occupation .. _ 1 Address RADIO AGE, Inc., 500 N. I My Name Dearborn St., Chicago, Ill. Address _..- ..._.-

BIMM WI WI IM IN IM = = = = 11 1= a mi t t t t t IMI I= M mi mC RADIO AGE for May, 1925 The Magazine of the Hour 63 KYW Heard Regularly in Samoa Sea nights,- a languid tropical SOUTHmoon, -the cool of the seaward veranda and the ever -present shimmer- ing glass on the table, with its attendant tinkle, have always been regarded as the white man's paradise, especially for those rovers who dot the spacious Pacific and 80 pages, profusely illustrated and who prefer to think of the United States of interesting data as a haven 7,000 miles or so away. for the Radio Fan; Trouble Shooting Chart, has Complete and Authentic List of Broadcasting Sta- But radio, with its magic wand, tions, Log Chart and Hundreds of Exceptional Values in annihilated distance and although the High Grade, GUARANTEED Equipment. A Postal brings it to nights, the moon- and the refreshments you -NO EXPENSE -NO OBLIGATION. FREE EXAMINATION -MONEY BACK, GUARANTEED! are still part and parcel of the colonials' Your money is still YOUR Money until you are thoroughly pleased and satisfied. lives, yet a new attraction has been Our money -back guarantee is your insurance of satisfaction. We are Heady for EVERY STANDARD added. Factory Built Set Knock Down Kit and all parte All of which should serve as a prelude to the letter of ecstasy received from A. F. Dunwoodie, of Apia, Samoa, a mere seven or eight thousand miles from ZILTMODEtÏ DD PP Chicago, in which it is stated that the L L-2 programs broadcast by KYW from the of Congress Hotel, Balloon Room the The "W. R. S." Ultradyne Kit is the ONL Y complete kit. It is the result of where Coon and Sanders play, -which the cooperation of the manufacturer of all its parts used in the Ultradyne music and fun goes under the name of circuit, R. E. Lacault, the designer of this famous circuit, and our own the "Insomnia Club," is heard nearly research engineers. W. R. S. Knockdown Kits contain everything for every night out in Apia, Samoa. building the circuit. Everything is included down to the last screw, nut This is not the first time that KY \V has I and wire. Packed in sealed cartons that eliminate all difficulty and doubt been heard in Samoa, for last year Mr. for the purchase and assembly of proper materials. wrote regard- Dunwoodie also the station Ultradyne Model L -2 ing his reception of its programs. But Phenix Ultradyne Kit as follows: Built to the thing which appeals to Mr. Dun - J. Special Low Loss 150 degrees Sensitizing Coupler woodie is the fact the Insomnia Club with Copper shield. 1 Oscillator Coupler Low Loss Your Order feature broadcast by KYW from the 1 Antenna Low Loss Tuning toil 4 Ultraformers. New improved long ware radio Congress Hotel every morning from I frequency transformer 4 Phenix matched transformers The Genuine Ultradyne a. m. to 2 a. m. and on Sunday morning 2 Uamtnarlund 0005 new type Low Loss Cond. I 3 2 Ultra vender dials New type Model L2 built of the exact from a. m. to a. m., reaches Samoa 1 Accuratuno control for coupler seven o'clock in the evening and 8 Na-ald De Luxe sockets as specified R. about 1 Patent Potentiometer parts by E. serves as an excellent aperitif for the 8 Amperitos 2 Patent Double Circuit racks Lacault in a beautiful solid evening meal of many a radio enthusiast. 1 Parent double Filament Control Jack 1 Cutler- nanuner switch mahogany piano hinged Between Chicago and Samoa, the latter 2 Thordarson Audio transformen being in the one hundred and eightieth 1 Variable Grid Leak cabinet 7 Eby Binding Posts wired by expert en- parallel, there is approximately six hours 2 Bakelite Binding post mountings 1 Dubilier .0005 with Grid leak mounts gineers in accordance with difference in time, making it possible for 4 Dubilier .00025 Mica Cond. 2 Dubilier .00L 3fica Cont. the inventor's specifica- Mr. Dunwoodie to sit down to his supper 1 Dubilier .005 Mica cond. table in Samoa and hear radio jazz music 1 7x30 Bakelite Drilled and Engraved Panel tions, $110.00. 1 7x30 mahogany baseboard broadcast by KYW from the Balloon 1 Ultrndsne book of instructions and blue prints 1 Bog of assorted screws, lugs. nuts Every Set is Guaranteed to arrive Room where the original Nighthawks, 40 feet of tinned. bus wire in your home in exactly Coon and Sanders, play at a time that Our Kit, Price Postpaid, $73.50 perfect condition is fairly close to the breakfast hour of the residents of the Middle West of the WHOLESALE RADIO SERVICE CO. United States. 9 Church Street Dept. R. A. New York City Apparently there is little interference developing in the South Seas, although thousands of ships on the Pacific are transmitting on 600 meters and KY\\ "s wavelength is 535.4 meters, for Mr. Dunwoodie does not report any trouble in picking up KYW's carrier wave and holding it until he has extracted all the OPEZ pleasure and fun from its Insomnia Club. 12SS Timer i. RADIO Banks Kennedy Now a Radio Age Storage "B" Battery lz lta Star GREAT FOR DX 2a Vocehs Lasts Indefinitely -Pays for Itself Selectivity Unex- Economy and performance onheard of before. Recharged Banks Kennedy. who has amused theuser at a negligible cost. Approved and listed as Standard by l earlier Radio Authorities including Pop- Radio Laboratories. P.D. countless thousands through his radio e..,...../_ Broadcast and Sea. Inst. Standards, Red!. uNews Ise Latex, Inc. and other Im. Amateur Types tant inatitunene. Equipped with Solid Rubber Case, an insur- antics from KYW and \VEBH, Chicago, ance acid and l,iair. Extra bears glass jars. heavy Price $10 tugedplain. Order yours today: has been "signed up" permanently as a You should read MONEY Jmt cyst: pmbu of batteries its advantages in SEND NO RADIO AGE performer from those and de 1 received- Extra Off r: a b tterleal series ß6l ltn ` l3. detail. Drop us a I,ahesrcemtSCtererwminfdng b.ttetea. 6 peeseat dleom f other broadcasting stations. Kennedy postcard todsyfor first started to twinkle when he intro- WORLD BATTERY COMPANY 1219 So. Wabash Ave., Dept. el Chicago, BL duced his famous "If I can Arrange It" Mak of Storage Batter; Pro a: e.wa. AMP.914 50, WO Asap. Sí4.50, .e0. song, and he has been at it ever since. AR tutyped with Solid Robber Boor. He may be heard from WEBH Tuesdays and Thursdays, after 11 p. m., and at KYW the first Saturday in every month beginning at 11:30 p. m.. on the Congress STORAGE BATTERIES WorldáoRO Hotel Jazz Carnival. iRQJSA ,.WEAFr W6Ns Wn.KN.____ _RF t Tested and Approved by RADIO AGE 64 RADIO AGE for MAY 1925 The Magazine of Me Hour Corrected List of Broadcasting Stations

KDKA Westinghouse Elactsio & Mfg. Co East Pittsburgh 309 KFQU W. Riker Holy City, Calf. 253 KDLR Radio Electric Co. Devils Lake, N. D. 231 KFQW C. F. Kiiierna North Bend, Waal, 246 KDPM Westinghouse Electric & Mfg. Co Cleveland, Ohio 270 KFQX Alfred M. Hubbard Seattle: Weals. 233 KDPT Southern Electrical Co San Diego, Calif. 244 KFQY Farmers State Bank Beld., Nob. 273 KDYL. Newhouse Hotel Salt Lake City. Utah 250 KFQZ Taft Radio Co Hollwyood. GMT 240 KDYM Savoy Theatre San Diego, Calif. 280 KFRJ Guy Simmons, Jr Conway, Ask. 250 KPZB Frank E. Siefert Bakersfield, Calif. 240 KFRM James F. Boland Fort Silt Okla. 263 KDZE Rhodes Department Store Seattle. W.h. 270 KFRN M. Laurence Short Hanford, Calif. 224 KDZI Electric Supply Co Wenatchee. Wash. 360 KFRO Curtis Printing Co. ri. Worth, Tex. 246 KFAD McArthur Bros. hlereantile Co. Phoenix. Arix. 360 KFRU Etherical Radio Co. Bristow ,Okla. 394 KFAE State Colle of Washington Pullman. Wash. 348 KFRW Unit ml Churches, of JIYmpia Olympia. Wash- 220 KF AF Western Radio Corporation Denver, Colo. 278 KFRX J. Gordon Klemgard Pullman. Wash. 217 KFAJ University of Colorado Boulder. Colo. 360 KFRY New Mexico College of Agriculture and Meishanke Arta, State College IT .M. 266 KFAN University of Idaho Moscow, Ida. 230 KFRZ The Electric Shop Harrington, Neb. 222 KFAU Boise High School Boise, Idaho 271 KFSG Angel. Temple Loa Angelea Calif. 272 KFAW The Radio Dm (W. B. Ashford) Santa Ana, Calif. 280 KFSY The Vo Blaricon Co Helena. Mont. 261 KFBB F. A. ButtreY & Co. Havre. Mont. 360 KFUJ Hopper Plumbing and Heating Co Breckenridge Minn. 242 KFBC W. K. Axbill Son Diego. Calf. 278 KFUL Thom. COMO It Bros. Music Co Galveston Tex. 258 KFBE Horn & Wilson's "Radioland San Luis Obispo. Calif. 218 KFUM W. D. Corley Colorado Springs, Colo. 242 KFBG First Presbyterian Church Tacoma, Wash. 260 KFUO Concordia Seminary St. Louis, Mo. 549 KFBK Kimball-Upson Co Sacramento, Cant 283 KFUP Fitzsimmons General Hospital Denver. Colo. 234 KFBL Leese Bros Everett, W.h 224 KFUQ Julius Brunton and So. Co San Francisco, Calif. 234 KFBU TM Cathedral Laramie. Wyo. 283 KFUR H. W. Peery and C. Redfield Ogden, Utah 224 KFCT1 Nielson Radio Supply Co Phoenix. Aris. 238 KFUS Louie L. Sherman Oakland. Calif. 233 !(FCC The First Congregational Choah Helena, Mont. 248 KFUT University of Utah Salt Lake City, Utah 271 KFCF Fronk A. Moore Walla Walla. Wash. 256 KFUU Colburo Radio Labe San Leandro, Calif.. 234 KFCL Leslie E. Rice L. Angeles, Cal. 236 KFUY Irvine M. Bouchard. Butte, Moot. 254 KFCP Ralph W. Flygare Ogden. Utah 360 KFUZ Y. M. C. A Virginia. Mien 248 KFCZ Omaha Central High School Omaha. Nebr. 258 KFVC Benalierg's Music Co Camden. Arkansas 242 KFDD St. Alich.b Cathedral Boise, Idaho 252 KFVD McWhinnie Electric Co San Pedro, Calif. 205 KFDH University of Arizona Tmcon, Axis. 368 KEVF Clarence B. Juneau Hollywood, Calif 208 KFDJ Oregon Agricultural College Corvallis, Oreg. 254 KFVH When Rodio Shop (Herbert Mon) Manhattan, Kansas 218 KFDM Alagnolia Petroleum Co Beaumont, T. 315 KFWA Browning Bros. Co. Ogden, Utah 214 KFDX First Baptist Church Shreveport. L. 360 KFWB Warner Bros. Hollywood. Calif. 252 KFD Y South Dakota State Colle Brookings. S. Dak. 360 KFWC L. E. Wall and C. S. Myer. s Upland. Calif. 211 KFDZ Harry O. Iverson Minneapolis. Minn. 231 KGB Tacoma Doily Ledger .Taeoma. Waah. 252 KFEC Meier & Frank Co Portland, Oreg. 248 KG0 General Electric Co Oakland, Calif. 361 KFEK Augsbury Seminars, Minneapolis. Minn. 261 KGU Marion A. Id ulrons. Honolulu, Hawaii Waikiki Beach 360 KFEL Winner Radio Corp. Denver, Colo. 254 ICGAV Portland Morning Oregonian Portlagd, Oreg. 491 KFEQ J. L. Scroggin Oak. Nebr. 268 KGY St. Martim College (Rob. Sebastian Rush) Lacy, Wmh. 253 KFER Auto Electric Servi. Co Fort Dodge. Iowa 231 KHJ Times-Mirror Co. Los Angeles. Calif. 405 KFEY Bunker Hill & Sullivan Mining and Concentrating Co Kellogg, Idaho 233 KHQ Louis Warmer Seattle, Wash. 273 KFFP Firm Baptist Church Moberly. Mo. 266 KJQ C. O. Gould Stockton, Calif. 273 KFFR Nevada State Journal (Jim Kirk) Sparks. Nev. 226 KJR Northwest Radio Service Co Seattle. Wash. 304 KFFV Graceland College Lamont Iowa 280 KJS Bible Institute of Loo Angeles, Ine Los Angeles, Calif. 293 KFFY Pine. & Murphy Music Home Alemmdria. L. 275 KLS Warner Brothers Radio Supplie, Co Oakland, Calif. 242 KFGB Heidbreder Radio Supply Co. Utica. Neb. 224 KLX Tribune Publishing Co Oakland. Calif. 508 KFGC Louhiano State University Baton Rouge. L. 254 KLZ Reynolds Radio Co. Denver, Colo. 283 KFG111 Chickasha Radio & Electric Co Chickasho. Okla. 248 KMJ San Joaquin Light & Pow. Corp. Fresno. Calif. KFGH Leland Stanford University Stanford University, Calif. 273 KMO Love Electric Co Tacoma, Wash. KPGQ Crary Hardware Co. Boone, Iowa 226 KNT Walter Hemrich Kukah Bay, Moka KFGX First Presbyterian Church Orange, Tex. 250 KNX Los Angeles Limning Express Los Angeles, Calif. 337 KFHA Western State College of Colorado Gunnison, Colo. 252 KOA General Electric Co enver, Co o. 323 Arahrms A. McCue Neah Bay. Wash. 261 KOB New Mexico College of Agriculture & Mechanic As .filtate College. N. Meg. 348 KFHH ta . . KFHJ Fallon & Co Santa Barbara, Calif. 360 KOP Detroit Police Department . Mich. 288 KFHL Penn College Oskaloosa. Iowa 240 KPO Hole Brut San Francisco, Calif. 428 KFHR Star Electric & Radio Co Seattle. Wash. 283 KPPC Pasadena Presbyterian Church Pasadena, Calif. 229 KFI E. C. Anthony. Inc Lo Angeles. Calif. 468 K2V Doubleday-Hill Electric Co Pittsburgh. Pa. 270 KFIF Boon Polytechnic Institute Portland, Oreg. 248 K W Chivies D. Harrold San lose. Calif. 240 KFIO North Central High School Spokane, Wash. 252 KR V. C. Battery & Electric Co Berkeley. Calif. 275 KFIO First Methodist Church Yakima. Waah. 242 KSAC Kansas State Agricultural College Manhattan, Kam. 341 KFIU Alaska Electric Light & Power Co Juneau. Alaska 226 KSD Post Dispatch (Pulitser Pub. Co.) St. Louis, Mo . 545 KFIX Reorganized Church of Jesus Christ of Latter Day Saints .lodeoendence. Mo. 240 KSL Radio Service Corp. of Utah Salt Lake City. Utah 299 KFIZ Daily Commonwealth and Oscar A. Holm an Food du Lae, .6. 273 KTHS New Arlington Hotel Co Hot Springs. Ark. 375 KFJB Marshall Electrical Co. Marshalltown, Iowa 248 KTW First Presbyterian Church Seattle, Wash. 454 KFJF National Radio Manufacturing Co Oklahoma City. Okla. 252 KUO Examiner Printing Co San Francisco, Calif. 246 KFJI Liberty Theat-o (E. E. Marsh) Astoria. Oreg. 252 KUOM State University of Montana Missoula. Montana 244 KFJL Hardsocg Manufacturing Co Ottumwa. Iowa 242 KWG Portable Wireless Telephone CO. Stockton, Calif. 360 KFJM University of North Dakota Grand Forks, N. Dak. 280 KWH Los Angeles Examiner Los Angeles. Calif. 360 KFJR Ashley C. Dixon & Son Stevensville. Moot. (nem) 258 KYO Electro Shop Honolulu. Hawaii 270 KFJX Iowa State Teacher's College Caular Falls, Iowa 280 KYW Westinghouse Electric & Mfg. Co Chicago, Ill. 535 KFJ Y Turmoil Radio Co Fort Dodge. Iowa 246 KZM Preston D. Allen Oakland. Calif. 360 KFJZ Texas Nation. Guard, Ono hundred od twelfth Cavalry.Fort Worth. Texas 254 WAAB Valdemar Jassen New Orleans, Ls. 263 KFKA Colorado State Teachers College Greeley. Colo. 273 WAAC Tulane University Now Orleans Le. 275 KFKB Brinkley-Jones Hospital Aseociatma Milford. Kaas. 286 WAAD Ohio Mechanics Institute Cincinnati, Ohio 248 KFKQ Conway Radio Laboratories (Ben H. Woodruff) Conway. Ark. 250 WAAF Chicago Daily Drovers Journal Chicago. Ill. 286 KFKU The University of Kans. Lawrence. Kans. 275 WAAM I. R. Nelson Co Newark, N. J. 263 KFKV F. F. Gray Butte. Moot. 283 WAAN University of Missouri Columbia. Mo. 254 KFKX Westinghouse Electric & Blanufaeturing Co Hastings. Nebr. 288 WAAW Omaha Grain Exchange Omaha. Nebr. 285 KFLA Abner R. Willson Butto, Mont. 283 WABA lake Forest-University Lake Forest Ill., 227 KFLB Signal Elertric Manufacturing Co. Alenominee, Mich. 248 WARS Harrisburg Sporting Goods Co Harrisburg, Pa. 266 KFLD Paul E. Greenlow Franklinton. L. 234 WASH Lake Shore Tire Co Sandmky. Ohio 240 KFLE National Educational Service Denvet Colo. 268 WADI Bangor Railway & Electric Co Bangor, Me. 240 KFLP Everett M. Foster Cedar Rapids. Ia. 256 WABL Connecticut Agricultural College Sore,, Conn. 283 KFLR University of New Mexico Albuquerque, New Mexi. 254 WARM F. A. Doherty Automotive and Radio Equipment Co Saginaw, Mich. 254 KFLU Rio Grande Radio Supply House Elan Benito, Tema. 236 WABN Ott Radio. Inc LaCrosse. Wis. 244 KFLV Rev. A. T. Frykman .. Rockford. III. 229 WABO Lake Avenue Baptist Church Rochester, N. Y. 283 KFLX George Roy Clough Galv.ton. Tex. 240 WABQ Haverford College. Radio Club Haverford, Pa. 261 KLZ Atlantic Automobile Co. Atlantic. Ia. 273 WABR Scott High School. N. W. B. Foley Toledo, Ohio 270 KFMB Christian Churches Little Rock, Ark. 254 WABU Victor Talking Mullen Co Camden. N. J. 224 KFMQ University of Akransas Fayetteville. Ark. 299 WABW College of Wooster Womter. Ohio 234 KFMR Morniogside College Sioux City. Iowa 261 WABX Henry B. Joy Mt. Clemens. Mich. 270 KFMT D. George W. Young lifinn.polia, Minn. 231 WARY John Magaldi, Jr Philadelphia, Pa. 242 KFMW M. G. Sater. Houghton. Mich. 266 WABZ Coliseum Place Baptist Church New Orleans, La. 263 KFMX Carleton College Northfield. Minn. 336 WADC Allen T. Simmons (Allen Th.trc) Akron. Ohio 258 KFNF Henry Field Seed Co Shenandoah. Iowa 266 WAFD Albert B. Parfet Co Port Huron. Mich. 233 KFNG Wooten's Radio Shop Coldwater, Miss. 254 WAHG A. H. Grebe & Co Richmond Hill. N. Y. 315 KFNJ Central Mo. Stare Teachers College Warrensburg. Mo. 234 WAMD Hubbard and Co Minneapolis, Minn. 244 KFNL Radio Broadcast Ass'n Paso Robles. Calif. 240 WBAA Purdue University W. Lafayette, Did. 283 KFNV L. A. Drake Battery and Radio Supply Shop Santo Rosa, Calif. 234 WRAC Clemson Aerie. College Qt1111/012 College, S. C. 931 KFNY Montana Phonograph Co Helena. Moot. 261 WBAH The Dayton Co AI buseapolis, Minn. 417 KFNZ Royal Radio Con...1' Burlingame, Calif, 231 WBAN Wireless Phone Corp Paterson, N. J. 244 K°04 Rhodes Department Store S.ttle, Wash. 384 WBAO James Millikan University Decatur, 111. 360 KFOC Firm Chrbtian Church Whittier, Calif. 236 WBAP Wortham-Carter Publishing Co. (St. Telegrom) Fors Worth. Tex. 476 KFOD Radio Shop Wallace. Idaho 224 WBAV Esser & Hopkins Co Columbus. Ohio 292 KF03 Moberly High School Radio Club Moberly. Missouri 246 WBAX John H. Stenger, Jr Wilkes-Barre, Pa. 254 KFOL Leslie II. Sehafbush Marengo. Iowa 234 WBAY W.tern Electric Co New York, N. Y. 492 KFON Echophone Radio Shop Long Beach, Calif. 234 WBEIG Irving Venially& Mattapoisett, Mesa. 748 KFOO Latter Day Saints University Salt Lake City. Utah 261 WBBH J. Irvine Bell Port Huron. Mich. 248 KFOP Rohrer Elec. Co Marshfield. Oro. 240 WBBL Grace Covenant Presbyterian Church Richmond. Va. 253 KFOR David City Tire & Electric Co David City. Nebraska 226 WBBM II Leslie Ads. Chi.go, 111. 226 KFOT College Hill Radio Club Wichita. liana. 231 WBBN Blake. A. B. Wilmington, N. C. 275 KFOU Hommel Mfg. Co Richmond. Calif. 254 WBBP Petoskey High School Petoskey, Mich. 248 KFOX Board of Education. Technical High School Omaha. Nebraska 248 WBBR Peoples Pulpit Asso Roseville, N. Y. 273 KFO Y Beacon Radio Send,. St. Paul. Minn. 226 WEBS Fir,, Baptist Church ., ....New Orleana, La. 252 KFPB Edwin I. Brown Saline, Wash. 224 WBBU 'Jenks Motor Bales Co Monmouth, Ill. 224 KFPG Garrets. nod Dennis L. Angeles. Calif. 238 WBBV Johnstown Radio Co Johnstown, Po. 245 KFPH Harold Chas. Mollandes Salt Lake Qty. Utah 242 WBBX Ruffner Junior High School Norfolk. Va. 222 Baader Dublin. Texas 242 WBBY Wa.hinoton Light Infantry Co. "B" 118th Inf. Charleston, 8. C. 268 KFPL C. C. Greenville. Tex. 242 WBBZ Noble B. Watson Indianapolis. Ind. 227 KFPM - The Nev Furniture Co Forestry Dept Los Angeles. Calif. 231 WBCN Foster & MeDoland Chicago, Ill. 266 KFPR Loa Angeles Co. 268 WB DC Baxter Laundry Co Grand Rapids. Mich. 256 KEPT Cape & Johnson Salt Lake City, Utah 1Kohlmoos. Inc San Francisco. Calif. 236 WBES Bliss Electrical School Takoma Park Md. 222 KFPV Rein. & Carterville. Mo. 268 WBGA Jone.s Elec. & Radio Mfg. Co Baltimore Md. 254 KFPW St. Johns M. E. Church Pine Bluff. Ark. 242 WBR Pennsylvania State Pollee Butler, Pa. 286 KFPX TOM Presbyterian Churcb KFPY Symons Investment Co Spokane, Wah. 283 WBRE Baltimore Radio Enshrines Wilkes-Barre. Pa. 231 KFOA The Principle St. Louis, Mo. 264 WBS D. W. May, Inc Newark N. J. 252 Publishing Co Fort Worth. Tex. 221 WBT Southern Radio Corp Charlotte. N. C. 275 KFOR TM SeruMlight Tait. Calif. 258 WBZ Westinghouse E. & M. Co Springfield. MM. 333 KFCM Kidd Brothers Radio Shop WCAD St. Lawrence University Canton. N. Y. 280 Southern Calif. Radio Amen Los Angel., Calif. 226 KFQG Burlingame, Calif. 231 WCAE Kaufmann & Baer Co. Pittsburgh, Pa. 461 KFOR Radio Service Co. WCAG Clyde R. Randall New Orleans, La. 262 FFQM Texas Highway Bulletin Austin, Tex. 268 WCAH Entrekin Elmtric Co Columbus. Ohio 286 KFQN Third Baptist Church Portland, Ora 283 WCAJ Nebraska Wesleyan lJnIverYtY University Place, Nebr. 283 KFQP G. S. Carson, Jr .Iowa City. Ia. 284 WCAL St. 0.af College Northfield. Minn. 336 KFQR Walter LaFayette Ellis Oklahoma City. Okla. 220 WCAO Senders & Stoman Co. Baltimore Md. 275 KFQT Texas National Guard Dennison. Texas 252 WCAP Chesapeake A Potoma Telephone Co Waohington, D. C. 468 RADIO AGE for May, 1925 The Magazine of the Hour 65

A Little Ray of Sunshine DUPLEX Standard Where Con- It's Needed densers 'Nona other so

"Listen in!" part of the Salvation Army band. Com- President A. J. Griffin of the Albany missioner William Peart made the ad- Park Kiwanis club, Chicago, is showing dress of acceptance. Before they left, one of the Salvation Army nurses and a the Kiwanians took a trip of inspection baby how to run the new radio set, a through the building. gift to Salvation Army's Women's Home The Women's Home and Hospital, a and Hospital, 5040 N. Crawford ave., refuge for unfortunate mothers, com- by the north -west Kiwanians. pleted by the Salvation Army last April, DUPLEX is located on an excellent site with woods Junior The radio set was presented at a and a pretty neighborhood about it. Con- luncheon served recently in the dining densers The grounds of the Home are being "Best room of the institution and attended by improved and when finished promise to at the fifty members of the Kiwanis club. make the place one of the beauty spots price Music for the luncheon was furnished by a of Chicago. In "Congress Classic" at KYW Free Sets for Slogans One of the most popular of the classic Radio sets with a total value of $64,000 Matched Sets type of entertainments put on by Station will be given to fans all over the United for Uniform KYW is given each Saturday night at States by the All- American Radio Cor- the Congress Hotel, Chicago, where poration of Chicago. The gifts will he given in return for suggestions for a new Dial Settings! KYW broadcasts a good portion of its slogan for the corporation's products. This most recent Duplex achieve- programs. All the fan has to do is to go to his nearest ment- Duplex Standard conden- The Congress Classic, as it is known dealer, get a blank and fill it in with his sers, specially tested, matched and on Saturday nights from 9:30 to 11:30 name, address and suggestion for the guaranteed to have identical capa- p. m., is booked by Frank Florentine, slogan. city curves, packed in sealed kits general For some time past, the All- American of three -has been enthusiastically manager of the Congress Hotel, has been using the slogan "The Largest welcomed everywhere by radio set and is announced by Eddie Borroff, Selling Transformer in the World." The builders, both professional and who also does the announcing on the production of other lines of radio appar- amateur. It is the only kit that Congress Carnival which runs on Satur- atus, such as the All -Amax Junior and affords uniform dial settings for day nights from 12 to 1 a. in. Senior semi -finished sets, has made Neutrodynes and all other tuned During the week there is dinner music necessary a change. The slogan should radio frequency circuits. Only one broadcast from apply to the complete line of transform- number to log -not three -when the Congress, made up of ers, sockets, semi- finished sets, etc. you use a Duplex Matched Kitl selections played by Joska DeBabary and Each dealer will award either a Senior his Folders telling how to make tuning Continental quartet, playing in the or a Junior All-Amax set to the winner. easier and reception better sent free Louis XVI room from 7 to 7:10; then a The contest will end the last of April. on request. journey to the Pompeian room to hear Duplex Condenser 8z Radio Corp. the Coon and Sanders Original Night- readers wish to show their 42 Flatbush Ave. Extension hawks from 7:10 to 7:20, and then back approval of RADIO AGE'S Brooklyn, New York to the Louis XVI room where Joska De- I stand against the Radio Babary finishes off with classical selec- Corporation of America, they can tions from 7:20 to 7:30. This concludes do it in the most practical way by TkM the early broadcasting from the Congress, sending in $2.50 for a year's sub- no' s d xO r" ",1ÇlAN0ENSERS but at 1 a. m., the Insomnia Club goes scription or if they are already sub- .TCED - ow"a. green, back on the air from the Balloon Room, scribers, urge a friend to subscribe. black and white Pack. Make Coon and Sanders original Nighthawks We believe the fans are with us. surie theseal is intact. playing until 2 a. tn. Address Radio Age, Inc. * Tested and Approved by RADIO AGE 66 RADIO AGE for May, 1925 The Magazine of the Hour WCAR Alamo Radio Electric Co San Antonio, T. 263 WHAP R. Alvin Simmons, 290 Flatboat, Ave Brooklyn. N. Y. 240 WCAS W. H. Dunwoody Industrial Institute Minneapolis. Minn. 280 WHAR Besolde House Atlantic City, N. J. 275 WCATI State College of Mines Rapid City. S. Dak. 240 WHAS Courier-Journal & Louisville Times Louisville, Ky. 399 Pa. WHAV Wilmington Electrical Specialty Co Wilmington, Del. 360 Rensselaer WCAV J "C Dice Electric Co LittledRook, Ar . 263 WHAZ Polytechnic Institute Troy, N. Y. 385 WCAX Unversity f Vermont Burlington, Vt. 250 WHB Sweeney School Co. Kansas City, Mo. 365 WCAZ Carthage College Carthage. ill. 246 WHBA C. C. Shaffer Oil City, Pa. 250 WCBA Charles W. Reihaehm Allentown, Pa. 280 WHBB Hobel's Stone Stevens Point. Wis. 240 WCBC University of Michigan Am Arbor, Mich. 280 WHBC Rev. E. P. Craham Canton. Ohio 245 WGBD Wilbur C. Votive Zion, Ill. 344 WHBD Chas. W. Howard Belefontaine, Ohio 222 WCBE II halt Radio- Co New Orleans, La. 263 WHBF Beardsley Specialty Company Rook Island. Ilunoh 222 WCBF Paul J. Miller Pittsburgh. Pa. 236 WHBG John S. Skane Harrisburg. Pa. 231 WCBG Howard S. Williams (Portable) Pascagoula, Mise. 268 WHBH Culver Military Academy Culver, Ind. 222 WCBH University of Mis Oxford. Hiss. 242 WHBI Cheaaning Electric Ca Chesaning. Mich, 227 WCBI Nicoll, Duncan & Rush Bemis, Tememee 240 WHBJ Lauer Auto Co Ft. Wayne. Ind. 234 WCBJ J. C. Maus Jammes. Louisiana 244 WHBK Franklin St. Garage. Inc Ellsworth. Maine 231 WCBL Northern Radio Mfg. Co Houston. Mo. 280 WHBL James H. Siascr Logansport, Ind. 220 WCBM Charles Swarm Baltimore. Md. 229 WHBM C. L. Carroll. Portable Station Chicago. Ill. 233 WCBN Jam. P. Boland Ft. B. Rarrfson, Ind. 266 WHBN First Ave. Methodist Church St. Petersburg. Florida 258 WCBO The Radio Shop. Inc Memphis. Tens. 250 WHBO Y. M. C. A., Summer Street Pawtucket, Rhode Inland 231 WCBQ First Baptist Church Nashville. Tem. 236 WHBP Johnstown Automobile Co Johantown, Pennsylvania 256 WCBR C. H. Messier Providence. R. I. 246 WHBQ St. John's M. E. Church South Memphis, Tem. 233 WCBT Clark University, Collegiate Dept Worcester. M. 238 WHBR Scientific Electric & Mfg. Co.. 3664 Vine St Cindruati. Ohio 216 WCBU Arnold Wirelexs Supply Co Arnold. Pa. 254 WHBS Edward Wm. Locke hlechani.hurg. Ohio 208 WCBV Tullahoma Radio Club Tullahoma. Tom. 252 WHET Thomas W. Tiszard. Jr Downers Grove. Ill... 206 WCBW George P. Rankin. Jr.. and Maitland Solomon %facers Ga. 226 WHBD B. L. Bing's Sons Anderson, Ind. 218 WCBX Radio Shop of Newark (Herman Luhtonkg, Newark, N. J. 233 WHBW D. R. Keenale Philadelphia. Pa... 215 WCBY The Forks Eectri.l Shop Bud Hill Falls, Pa. 268 WHEC Hickson Electric Co.. loo Rochester. N. Y. 258 WCBZ Coppotelli Bros. Music House Cbieago Heights. Ili. 248 WHK Rodiovoa Company Cleveland Ohio 273 WCCO Washho .- Croshy Co Twin Cities. Minn. 416 WHN George Schubert New York. N. Y. 360 WCEE Charles E. Erbeteio, Villa Olivia near Elgin. Ili. WHO Banker, Life Co. Dee Moines. Ia. 526 WCK 8tiz- Br -Fuller D. G. Co St. Louis. Mo. 278u WIAD Howard R. Miller Philadelphia. P. 254 WCX Free Regs Detroit. Mich. 516 WIAK Journal -Stockman Co Omaha, Nebr. 273 WDAE Tampa Daily Times Tampa Fla. 365 WIAD Chronicle Publishing Co. Mario,, Ind. 226 WDAF Kam. City Star Kane. City. Mo. 365 WIAS Home Electric Co Burlington. Iowa 283 WDAC J. Laurence Martin Amarillo, Tex. 263 WIBA The Capital Times-Studio Madison, Wu. 236 WDAH Trinity Methodist Church (South) El Paso, 268 WIK K. & L. Co McKeesport, Pa 234 T. WIL Continental Electric WDAR Lit Brothers Ph0adelphl . Pa. 394 Supply Co Washington. D. C. 360 WDAY Radio Equipment Corp. Fargo. N. Dak. 244 WIP Gimbel Bros. PhiladelphiaPhiladelphia, P. 509 WDBA Fred Rar Columbus. Ga. 236 WJAB American Electric Co. Lincoln, 229 WDBB A. H. Waite & Co.. Inc. Taunton. M. 229 WJAD Jacksonh Radio Engineering Laboratories Waco, Texas 352 WDBC Kirk. Johnson & Co. Lancaer, Pa. 258 WJAG Norfolk Daily News Norfolk. Nehr. 283 WDBD Herman Edwin Burns NIartioahurg, W. Va. 268 WJAK Clifford L. White Greenman. Iowa 254 WDBE Gilham-Schoen Eft, Co Atlantic. Ga. 278 WJAM D. M. Perham Cedar Rapids. Iowa 268 WDBF Robert G. Phillips Youneaten. Ohio 315 WJAN Peoria Star Peoria, ILL 280 WDBH C. T. Scher. Co Wormier. M. 268 WJAR The Outlet Co. (J. Samuel. & Bro.) Providence. R. I. 305 WDBI Radio Specialty Co... St. Petersburg, Fla. 226 WJAS Pittsburgh Radio Supply Howe Pittsburgh, Pa. 286 WDBJ Richardson Wayland Electric Corp Roanoke. Va. 229 WJAZ Chicago Radio Laboratory Chicago. Ill. 268 WDBL Wisc. Dept. of Market Steve. Point, Fis. 278 WJD Denison University Oraniteville, Ohio 229 WDBN Eleetrio Light & Power Co ..Banem, Me. 252 WJJD Suprrene Lodge. Loyal Order of Moose Mooaeheart, Ill. 303 Rollins Winter WJY Radio Corp, of Anna New York. N. Y. 455 WDBO College Iue. Park. Fla. 240 Radio WDBP Superior State Normal School Superior Wis. 261 WJZ Corp. of Ana New York. N. Y. 455 WDBQ Morton Redo Suoplr Co Salem, N. J. 234 WKAA H. F. Poor Ceder Rapids. Iowa 278 WDBR Tremont Tempe Baptist Church Boston, hiss,. 256 WKAD Chas. Looff (Cresecnt Park) East Providence, R. I. 240 WDBS S. M. K. Radio Corp. D.-ton. Ohio 283 WKAN United Battery Serir. Co Montgomery. Ala. 226 WOBT Taylor Book Store Hattiesburg. 31is. 236 WKAP Dutee W. Flint Cranston. R. I. 234 WDBV The Strand Theatre Fort Wayne. Ind. 258 WKAQ Radio Corp. of Porto Rico Ban Jus,. P. R. 340 WDBW The Radio Dee Columbia. Tenn. 268 WKAR Michigan Agriculture College E.t Laming, Mich. 285 WKAV Laeoria Radio Club Laconia. N. H. WD/3X Otto Baur New York. N. Y. 233 WKBE K. 254 WDBY Noah Shore Congr.atiooal Church ...... Chicago. lu. 258 & B. Electric Co Webster. Mamaehwetta 231 WKBF Dutee Wilcox Flint Cre.ten, Rhode island 286 WDBZ Boy Scouts, City Hall Kingstown, N. Y. 233 Wky WDM Church of the Covenant Washington. D. C. 234 WKY Radio shop Okla. City, Okla. 275 WI-AG Cutting & Washington Radio Conn \linnmpdu, Minn. 417 WDWF Cranston. R. I. 440 WLAL First Christian WDZ J. L. Bush Tuscola. R1. 278 Church Tuba. Okla. 250 WEAA F. D. Follain flint. Mich. 250 WLAP Wm. V. Jordan Louisville, Ky. 288 WEAF American Telephone & Telegraph Co New York, N. Y. 485 WLAQ Arthur E. Shilling Kalam.00, Mich. 283 WEAH Wichita Board f Trade .. Wichita, Kans. 280 WLAX Putnam Electric Co Greencastle, Ind. 231 Cornell WLB University of Minnesota hlisaneapolie, Minn. 278 WEAI University .Ithaca. N. Y. 286 Wisconsin WEAJ University of South Dakota Vermillon, S. Dak. 283 WLBL State Dept. of Markets Stevempoint, Wis. 278 WEAM Borough of North Plainfield (W. Ctb.on Buttfield).. North Plainfield, N. J. 286 WLS Sean Roebuck & Co. Chicago. Ill. 344 WEAN Shepard Co Providence. R. I. 273 WLW Crosley Mfg. Co.. .. Cincinnati. Ohio 422 WEAO Ohio State University Colonels.. Ohio 293 WMAC J. Edw. Page (Olive B. Meredith Cazenovio. N. Y. 261 WEAP Mobile Radio Co Mobile. Ala. 263 WMAF Round Rills Radio Corp Dartmouth, M... 360 WEAR Goodyear Tire d Robber Co Cleveland. Ohio 389 WMAH General Supply Co Iineobe. Nehr. 254 WEAU Davidson Bros. Co Sioux City. Iowa 275 WMAK Norton Lahontorir, Lockport. N. Y. 273 WEAY Iris Theatre (Will Horowitz. Jr.) Houston, Texas 360 WMAL Trenton Hardware Co Trenton. N. J. 256 WEB Benwood Co. 8t. Louie, Mo. 273 WMAN First Baptist Church Columbus, Ohio 286 WEBA Electric Shoo Highland Perk, N. J. 233 WMA9 Chicago Daily News Chicago, ¡U. 447 WEBC Walter Cecil Bridges Superior. Ris. 242 WMAL, Alabama Polytechnic Institute Auburn. Ala. 250 WEBD Electrical EC ipmeot and Senwe Co.. Anderson, Ind. 246 WMAY Kingshighway Presbyterian Church St. Louis. hio. 280 WEBE Roy W. Walker Cambridge. Ohio 248 WMAZ Mercer University Macon. Ga. 261 WEBH Edgewater Basch Hotel, Chicago Evening Pont station Chicago. III. 370 WMBF Miami Beach, Fla. 384 WMC Commercial Appeal Memphis, Tenn. 503 WEBJ Third Avenue Roilway Co New York. N. Y. 273 Ainsworth WEBM Radio Corporation of America Portable 226 WMH -Gates Radio Co Cincinnati. O. 321 WEBP E. B. Peditord New Orleans. La. 280 WMU Douhrcdal Hill Elec. Co Washington. D. C. 260 WEBT The Dayton Coop. industrial High School Dayton. Ohio 270 WNAC Shepard Stores Boston, blase. 284 WNAD University of Oklahoma Norman, Okla. 258 WEBW Beloit College Beloit Wis. 283 WNAL WEBX John E. Cain, Jr Nashville, Tenn. 263 Omaha Central High School Omaha. Nebr. 255 WNAP Wittenberg Colic.e 271 WEBY Hobart Radio Co Rasliodalc, M., 226 Springfield. Ohio WEEI The Edison Electric Illumiatieg Co Boston, Mas. 475 WNAR First Christian Church Butler. Mo. 230 WNAT Lennig Brothers Co. (Plederiek Leonid Philadelphia. Pa. 254 WEMC Barrie. Springs. Mich. 285 WNAX WEW St. Louie University St. Louis, Mo. 280 Dakota Radio Apparatus Co. Yankton. S. Dak. 248 News WNYC Dept. of Plant and Structures New York. N. Y. 526 WFAA Dallas & Dalla Joarml Dill.. Tex. 472 Page WFAM Times Publishing Co. S. Cloud. Minn. 273 WOAC Organ Co Lima. Ohio 260 WFAV University of Nebraska. Department of Electrical Eogtoeering, Lincoln. Nehr. 275 WOAE MDdiand College Fremont. Nehr. 280 WFBB Eureka College Eureka, Ill. 240 WOAF Tyler Commercial College Tyler. Texas 363 WFBC First Sophist Church Knoxville. Teno. 250 WOAG Apollo Theater (Belvidere Amusement Co.) Belvidere. Ill. 274 WOA1 Southern Equipment Co. San Auto,io. Tex. 392 WFBD Getbsemaoe Baptist Church Philadelphia. Pa. 234 WOAN Vaughn WFBE John Van De Walle Seymour, Ind. 226 Conservatory of Music (Jam. D. V.ugho).... Lawrenceburg. Teno. 280 WFBD Gethemane Baptist Church Philadelphia. Pa. 234 WOAO Lyradion Mfg. Co MI hawaka, Iod. 369 WOAR Luradakow. Henry P Kenosha, NFL,. 225 Van Waue . ymour, WFBE John De .So Ind. 226 WOAT Boyd WFBG The Wm. F. Cable Co. Altoom. Pa. 261 M. Stomp Wilmington, Del. 360 New WOAV Pennsylvania National Guard, 2d Battalion. 112th I,fantry....Erie, Pa. 242 WFBH Concourse Radio Coporatio, York N. Y. 273 Woodmen WFBJ St John's University Collegeville, Minn. 236 WOAW of the World Omaha Nebraska 526 WFBQ Wynne Radio Co Raleigh. N. C. 255 WOAX Franklyn J. Wolff Trenton. N. J. 240 Fifth Inf. Md. Nat" Guard. 5th Reg. Armory Baltimore, WOC Palmer School of Chiropractie Davenport, Iowa 484 WFBR Md. 452 WOCL Hotel Jamestown, Jamestown. WFBT Gloucester Co.. Civic League Pitman. N. J. 231 Inc N. Y. 275 Ainsworth -Gates Radio Co Cincinnati. Ohio WOI Iowa State College Am.. Ia. 207 WFBW 309 WOO John Wanamaker Pa. WFBY Signal Officer Ft. Ben Harrison. Ind. 258 Philadelphia. 509 WFBZ Knox Couege Galesburg, m. 254 WOR L. Bamberger and Co Newark. N. J. 405 Philadelphia, WORD Peoples Pulpit Assn Batavia, M. 275 WFI Strawbridge and Clothier Pa. 394 WOS State WFUV G. Pearson Ward Springfield. Mo. 252 Marketing Bureau Jefferson City, Mo. 440 WFUW Earl William Lewis Moberly, Mo. 233 WPAB Pennsylvania Stare College State College. Pa. 283 WPAC Dooeldvon Co Okmulgee, Okla 360 Lancaster Electric Supply err Co Lancaster. Radio WGAL Conatruetien Pa. 248 WPAJ Doolittle New Conn. WGAQ Youree Hotel Shreveport, L. 252 Radio Corp. Raven. 268 South Rend Tribune South Bend. 360 WPAK North Dakota Agricultural College Agricultural College, N. D. 283 WGAZ Ind. WPAL Superior Radio & Telephone Ohio 286 WCBB Harry H. Carman. 217 Bedell St Freeport. N. Y. 244 Equipment Co. Columhw, Baptist Memphis. WPAU Concordia College 'Moorehead. Minn. 286 WGBC First Church Tenn. 266 W. Va. WGBF Fink Furniture Co Evansville, Ind. 217 WPAZ John R. Koch (Dr.) Charleston. 273 WGBG Brietenhach's Radio Shop Thrifton. Va. 226 WPC The Municipality of Atlantic City Atlantic City. N. J. 300 Fall Rive! Herald Pub. Co 209 WQAA Horace A. Beale. Jr Parkersburg. Pa 270 WGBH (Portable) WQAC E. B. Amar.1o. 234 WGBI Frank 8. Mlegargee Scranton. Pa. 240 Gish Texas Lawrence Campbell Johnstown. Pa. WQAE Moore Radio News Station (Edmund B. Moore/ Springfield. Vt. 275 WGBK 248 WQAM Electrical Equipment \Miami. Fla. 283 WGBM Theodore N. Salty Providence, R. 1. 234 Co Huh Radio Shop LaSalle. WQAN Scranton Tim. Scranton. Pa. 280 WCBN IM. 266 W QAO Calvary New York. N. 360 WGBO Dr. Roses Arian San Juan. P. R. 275 Baptist Church Y. M. L. Price Music Co Tampa, WQAS Prince -Wafter Co Lowell. Maas. 266 WGBP Fla. 250 WQJ Calumet Chicago. 447 WCBL Elyria Radio Asso. (Albert H. Error) Elyria. Ohio 227 Rainho Broadcasting Co. DL Stout Institute Menominee, Wis. WRAA The Rice Institute Houston. Tex. 256 WGBQ 234 WRAF The Radio Club (Inc.) Lame.. Ind. 224 WGBR Marshfield Broadcasting Alan Marshfield. Wins. 229 Gimhel Brothers New York. 315 WRAK Economy Light Co Eseaaha, Mich. 256 WGBS N. Y. WRAM Lombard College Galesburg, 244 WGBT Furman University Creermlle, S. C. 236 Ill. WGBW Valley Theater Spring Valley, WRAN Black Hawk Electrical Co. Waterloo, Iowa 236 Ili. 212 WRAO St. Louis Radio St. Louis, 263 WGBX University of Maio Orono. Me. 252 Service Co Mo. Progress Sales Co R. R. No. 2 WRAV Antioch College Yellow Springs. Ohio 242 WGBY 218 WRAW Avenue Radio Shop (Horace Good) Reading, Pa. 238 WGI American R. & R. Co. Medford Hillside. Mass. 261 D. The Tribune Co Chicago, WRAX Flaxen', Garage Olone.ter City. N. J. 268 WGN Ill. 370 WR BC Itnamuel Church Valparaiso 278 WGR Federal T. and T. Co. Buffalo, N. Y. 319 Lutheran Ind. WRC Radio Corp. of . Washington. b. C. 468 . Co Schenectady N. Am. WGY General El Y. 379 WREO Reo Motor Car Cn Lansing, Mich. 286 WHA University of Wieemebe Madison, Wu. 535 Milwaukee. WRHF Washington Radio Hospital Fund Washington, D. C. 256 WHAD Marquette University Wis. 280 WRK Doron Bros Hamilton, Ohio 360 WHAG University of Cindonati Cincinmt4 Ohio 222 WRL Union College Schenectady. N. Y. 270 WHAH Hafer Supply Cn. Joplin. M. 283 WRM 273 of Rochester (Eastman School of Mugie) Rochester. N. University sr Illinois Urbana III. WHAM University Y. 278 WRR Police and Fire Signed Department Dallas. Tex. 261 RADIO AGE for May, 1925 The Magazine of the Hour 67 Where the HOWLS Come duce this great difference in amplification value. It is claimed by many that Now you can From resistance coupled amplification is better, (Continued from page 8) because there will be no distortion, but there is more or less distortion UNDERSTAND No great trouble is experienced here, every time the signal is passed through unless the amplification is carried too a tube and there is no reason why a RADIO! far. Usually two stages will suffice carefully designed transformer should if more are added, the tube and noises, increase this distortion, although it is 514 static and vibrations of the set are so true that because of the greater amplifi- PAGES magnified that the clearness of reception cation afforded by the transformer is impossible, although some set manu- method, the inherent noises from the 100,000 facturers have succeeded in so carefully tubes and other sources will be amplified SOLD balancing their circuits that three stages in proportion to the signal amplification. COMPILED used in some cases. BY are For this reason we may get the im- HARRY F. HART There are two popular methods of pression of more distortion. The original E E. obtaining audio frequency amplification, cost of installation of the resistance Formerly with both of which have their advantages and type is necessarily greater, due to the the Western disadvantages. One is the transformer Electric Co., fact that more tubes, sockets and bat- and U. S. coupled type and the other is the resist- teries are required to get the same volume Army In- ance coupled arrangement, and at this which may be obtained by the trans- structor of there is considerable Radio. Tech- time talk about former arrangement. nically edited which is the better of the two. In by F.H. Doane resistance coupled amplification, very high resistances are used between Amateurs Get New Waves the Afore than 100,000 radio fans rely on this I. C. S. plate battery and the plate, which makes Secretary Hoover today authorized Radio Handbook to take the mystery out of radio. it necessary to use extremely high voltages the amateurs to use waves less than one Why experiment in the dark when you can quickly learn the things that insure success/ Hundreds of on the plate circuits. It is not uncommon meter in length in addition to their illustrations and diagrams explain everything so you can get the most out of whatever receiver you to use from 150 to 300 volts, according previous assignment. The permission build or buy. to the amount of resistance used. This covers the channels between .7477 and .7496 Contents: Electrical terms and cir- high pressure is necessary in order to of a meter, in other words, a band cuits, antennas, batteries, generators force the proper amount of plate current at about the 3 -4 meter wavelength. and motors, electron (vacuum) tubes, most receiving hook -ups, radio and through the high resistance. Few people realize the immense number audio frequency amplification, broad- In this case there is no amplification of possible operating channels that lie cast and commercial transmitters and receivers, wave meters, super- regenera- with the exception of that due to the in the low wavelengths. While the tion, codes, license rules. Many other tube, and in order to get any great band now assigned to amateurs is only features. amount of volume, more stages must be nineteen one-thousandths of one meter A practical book. Written by experienced radio used than would be necessary with in width, its extremes are separated engineers, in plain language. Something useful on every one of its 514 pages. A book that will save transformer amplification. With more by one thousand kilocycles. The secre- you many times its small cost. tubes, we are sure to find more tube tary pointed out that if it ever became Just mail the coupon with a dollar bill and your noises in the final stage. feasible to conduct broadcasting on name and address, and this 514 -page I. C. S. Radio Taking for example a two stage resist- these frequencies, it would be possible Handbook will he sent to you by return mail. Note the other good ance coupled amplifier, using the stand- to place within this band 100 broad- books listed below at low prices. ard UV =201 -A tubes with an amplification casting stations and give Ito each the r constant of approximately 8, we would present separation of ten kilocycles, International Correspondence Schools have 8x8, or roughly and said further that all speaking, an the stations Box 8781 -D, Scranton, Penna. amplification of 64, while with a two - in the world could operate in the upper I enclose S for which send me. postpaid. the stage, transformer coupled amplifier half of the one meter band. The art Handbooks marked X. at SI each. it is understood that H I am not tirely satisfied I may return them within using transformers having a ratio of 4 to has, of course, not developed to make five days andn you will refund nu- money. 1, we would have 8x4x8x4, or 1024. this possible, but the amateurs now In this case, also, much less plate have an opportunity to see what they RADIO HANDBOOK, $1 Automobile Handbook $1 voltage would be required to pro- can do. Electrical Handbook Si Chemistry Handbook SI Pharmacy Handbook 81 Traffic Handbook SI Building Trader Handbook SI 'Machine Shop Handbook Si Salesman's Handbook Si Advertising Handbook SI The Radio Age Annual for 1924! Bookkeeper's Handbook Si Civil Eneneer , Handbook sl ONLY A FEW LEFT AT 50e EACH Steam Engineer's Handbook Si If you have not bought your copy of the famous Name RADIO AGE ANNUAL for 1924, you may get one Address at a special price of 50 cents by filling in the coupon Enclose 81.50 J each book if you want the Lealheroid binding. AU of the above books san be had in this binding below and sending it with stamps, money order or rcpt the Traffic Handbook and the Building Trader draft, at once. The supply is nearly exhausted, and Handbook. no more will be printed, so ACT NOW!

HONEYCOMB CONS 1924 ANNUAL COUPON The Universal all -wave Radio Age, Inc., inductance. Back and 500 N. Dearborn St., front panel mountings. Ill. Send 2Sc for Super Chicago, Het., R. F. and Honey- Gentlemen: Please find enclosed 50 cents, for which you may send me a comb Coil Circuits and copy of the RADIO AGE ANNUAL for 1924, in accordance with your special Complete Catalog. Chas. A. Branton, Ile. price offer for April. oe.. ais Maln st., Buf13 falo, M. Y. Name Address LET RADIO AGE help make this a City_. State._ Real Radio Summer for Youl Subscribe 5-25 Now! * Tested and Approved by RADIO AGE 3t 68 RADIO AGE for May, 1925 The Magazine of the Hour

WRW Tarrytown Radio R. Labs Tarrytown. N. Y. 273 WTAL Toledo Radio k Electric Co. Toledo. Ohio 252 WSAB Southeast Missouri State Teaches College Cape Girardeau Mo. 275 WTAM Willard Storage Battery Co Cleveland. Ohio 369 WSAC Clemson Agricultural College Clemmoo allege, S C. 336 WTAP Cambridge Radio k Electric Co. ambridn Iss. 242 WSAD J. A. Foster Co. Providence, R. I. 261 WTAQ S. H. Van Gordon k Son OW.. twis. 220 WSAG Loren Vanderbeck Davis St. Peterohurg, Fla. 264 WTAR Reliance Electric Co. Norfolk. Va. 280 WSAI United States Playing Cards Co. Cincinnati. Ohio 325 WTAS Charles E. Erbstein Elgin, Ill. 303 Crave City College Crove City, Po. 258 WTAT Edison Electric Illuminating Co. Borten. Maas (portahle) 244 WSÁÑ Allentown Call Publishing Co. Allentown. Pa. 229 WTAU Ruegg Battey & Electric Co Tecumseh, Nehr. 242 WSAP Seventh Day Adventist Church New York. N. Y. 263 WTAW Agricultural & Mechanical College of Taws College Station. Tex. 280 WSAR Doughty & Welch Electrical Co Fall River, Mos.. 254 WTAX Willis., Hardware Co. Streator, nl. 231 WSAU Campo MarionfeId Cheshem. N. H. 229 WTAY Oak Leaves Broadeastng Station Oak Park. T8. 283 WSAU C. W. Vick Radio Cooatruction Co Houston. Tes. 360 WTAZ Thomas J. McGuire Lambertville, N. J. 283 WSAY Irving Austin (Port Chester Chamher of Commeree).. Port Chester. N. Y. 233 WTHS Flint Senior High School Flint. Mich. 218 WSAZ Ch.. Electric Shop Pomeroy. Ohio 258 WTG Kansas State Agricultural College Manhattan. Kam. 273 WSB Atlanta Journal Allenta. Ga. 428 WTIC Travelers Insuranm Co Hartford. Cono. 323 WSL J. and M. Elec. Co Utica, N. Y. 273 WTX H. C. Saal Co Chicago, nl 268 WSMH Shattuck Music House Owosso, Mich. 240 WWAD Wright & Wright (Inc.) Philadelphia. Pa. 360 WSOE School of Engineering Milwaukee, Wio. 246 WWAE The Alamo Ball Room Joliet. Ill. 242 WSRF Bardem Sala and Service Broadleods. 111 233 WWI Ford Motor Co Dearborn. Mich. 273 WSUI State University of Iowa Iowa City. Iowa 498 WWJ Detroit Nein (Evening News Assn./ Detroit, Mich. 752 WTAB Fall River Daily Herald Publishing Co. Fall River, Mas. 248 WWL Loyola University New Orleans. T.a. 760 WTAC Penn Traffic Co .. ..Johnstown, Pe. 360 WWOA Michigan College of Mine. Houghton, blich. 244 WTAF Luis J. Callo New Orleans. La. 242 Canadian Stations

CFAC Calgary Herald Calgary, Alberta 430 CHXC J. R. Booth Ottawa. Oat. 435 Ontario 400 CH Northern Electric Co Montreal. Quebec 410 CFCA Star Pub. & Pitt. Co Toronto. Jarvis Baptist Church Toronto, Ont. 312 CFCF Marconi 1Virele_cs Telen. Co. Canada hlontred. Quebec 440 CJCA Edmonton Journal Edmonton, Alberta 455 CFCH Abitibi Power & Paper Co Iroeuoie Falls, Ont. 400 London Free Pray Pets. Co London. Oc... 430 CPC! L Cie de L'Evenement .. Quebec, Quebec 410 CJCD T. Eaton Co Toronto. Ont. 410 CFCK Radio Supply Co Edmonton. Alberta 410 CJCE Bnrott -Shaw Radio Co Vancouver, B. G. 420 . W. W. Crani Radio ...... Ca lgary.l g a r y Alberta 440 CJCF The News Record Kitchener, Ont. 295 CFC Q Radio Soecieltiea (Ltd.) . .. Vancouver, B. C. 450 Maritime Radio Corp St. John, New Brunswick 400 CFCR Lurontide Air Service Sudbury. Ont. 410 CJCK Radio Corp. of Calgary Calgary, Alta. 316 CFCT Victoria City Temple Victoria. British, Col. 410 CJCM J. L. Phillips Mont Joli, Quehoo 430 CFCU The Jack Elliott Radio Limited....., Hamilton, Ont. 410 CJCN Binions Agnew & Co Toronto. Ont. 410 The Radio Shop London. Ont. 420 CJSC Evening Telegram Toronto,Toronto Ont. 430 Sparks Co - Namimo, B. C. 430 CKAC L Presse Pub. Co Montreal. 430 CFDC Vancouver 410 CFHC Henry Birks & Som - Calgary, Alta. 440 CKCD Daily Province Vancouver, B. C. CFLC Chas. Cuy Hunter tit Adelaide St.. London. Ont. 410 CKCE Canadian Indepead. Telephone Co Toronto, Ont. 450 CF The Electric Shop (Ltd.) .. Saskatoon. Saskatchewan 400 CKCK Leader Puh. Co. Regina, Saskatchewan 420 CFÁC Queens University Kingston. Ontario 450 CKCO Ottawa Radio Aazadatioo, .. Ottawa. Ont. 440 CFUC University of Montreal Montreal, Quebec 400 CKCX P. Burns & Co Calgary, Alberta 440 Westminster Truc. Co Raw Westminster, B. C. 440 CKLC Wilkinson Electric Company Calgary, Alberta 400 CFYC Victor Wentworth Odium...... Vancouver. B. C. 400 Wentworth Radio Supply Co. Hamilton. Ont. 410 CHAC Radio Engineers Haltfaz. Nova Scotia 400 CNRÁ Canadian National Railways Moncton. N. B. 313 Albertan Publishing Co...... Calgary, Alberta 410 CNRC Canadian National Railways Calgary, Canada 357 CHCB Marconi Company Toronto, Ont. 410 CNRE Canadian National Railway. Edmonton, Alta. 455 CHCD Canadian Wireless & Eke. Co Quebec, Quebec 410 CNRM Canadian National Railways Montreal. P. Q. 410 CHCE Western Canada Radio Sun. (Ltd.( Victoria. B. C. 400 CNRO Canadian National Railway, Ottawa. Ont. 430 CHCL Vancouver Merchants Exchange Vancouver. B. C. 440 CNRR Canadian National Railway. Regina. Sash. 312 CHCM Piler & hlrCormnck Calgary. Alherh 415 CNRS Canadian National Railways Saskatoon. Sash. 329 CHCS The Hamilton Spectator Hamilton. Out. 420 CNRT Canadian National Railways Toronto. Ont. 357 CHIC Northern Electric Co Toronto. Ont. 356 CNRW Canadian National Railways Winnipeg. Alan. 384 CHNC Toronto Radio Research Toronto. Ont. 350 Cuban Stations

. Habana 400 2K Alvara Daze Habana 200 PWX Cuban Telephon Co - 2DW Pedro Zeyaz lieham 300 2HS Julio Power Hahena 180 2AB Alberto S. de Bustamente - - Habana 240 201 Oscar Colado Habana 290 Mario Careia Velez Habana 360 2WW Amadeo Bastion ...... Hahana 260 SEV Leopoldo > . n Figueroa Colon 360 2B Frederick W. - W. Barton ... Hahen. 320 6KW Frank H. Jones...... Tuinucu 340 2CX Frederick - Westinghouse Elec. Co "" -Hole. 220 6KJ Frank H. nonas Tuinucu 275 . 230 Antonio 170 - H.ahm. T. Figueroa Cienfiegos 2TW Roberto E. Remixes - 2HC Heraldo de Cuba...... 'Habana 275 6DW Eduardo Terry .. Cienfiegos 225 2LC Luis Casas.. .. _..Habana 250 6BY Jose Canduxe Cten8ego, 300 . . - Cienfiegos 200 . Habana 350 Valentin Lllirarri E. Sanchez de Fuentes.. - 2KD - 2MN Fausto Simon ...... Habana 270 86Y Alberto Ravelo Stgo. de Cuba 250 2MG Manuel G. Salon .. . ..Ilahan 280 Andrea Vim. Stgo. de Cuba 225 2JD Raul Parez Falcon .. Rah ana 150 8DW Pedro C. Anduz Sigo, de Cuba 275 European Broadcasting Stations British Stations

2L0 London ....365 SNO Newcastle 400 SIT Birm ham 475 SSC Glasgow 420 5WA Cardiff 3S0 2BD Aberdeen 492 6BM Bournemouth 385 6SL Sheffield 'relay otationl 303 2ZY Manchester 375 French Stations rn Lions 740 SM Paria 1 780 FL Paris tEife1 Tower) ...... 2 600 ESP Paris 450

MARVELOUS NEW 5000 AUDIO TRANSFORMER RADIO DEALERS adds musical aualityto any net far beyond anything you ever heard buy from before. KARAS, ll ARMOé IK Amplifies low, middle d high tones-all to the same big volume, thus eliminating distortion. Brings HUDSON-ROSS out the vita harmonics and 123 W. Madison St. Chicago ton es of music. Price $7,00. Write. Send for dealers discount. N. Rocket) SI.. Chinga each in any value Raps Electric Co, Dept. Si -93 4042 from to l0 FRESHMAN SUPERIOR IF YOU DON'T See what you need in RADIO ACE'S remain arose at sili titres MARSHEIL)<. Rar" Made of high resistance material impreg- Advertising Columns, write to ecëivers`y nated throughout (not coated paper). Un- Embodying a marvelous New ;E affected by climatic conditions. Will not the Radio Age Buyers' Ser- deteriorate. Clampid between solid knurled vice, 500 N. Dearborn St., Non -Oscillating Principle ferrules assuring rigid construction and Sold Direct on Free Trial nod Easy Terms firm contact at all times. Chicago, and all buying speci- At your dealer's. otherwise send purchase Write for catalog and Special Offer price and you wilt be supplied postpaid fications will be furnished you Chas. Freshman Co.. tae.. 2.0.248 W. 40th St. Marshall Radio Products, inc. Freshman Bldg.. N. Y. free of charge. De pt. 58.95 Marshell Blvd. & 19th SL. Chicago F Tested and Approved by RADIO AGE RADIO AGE for May, 1925 The Magazine of the Hour 69

Thorola "Doughnut Coil" regulate the reproducer. The height of Radio Concerns Reorganize the Baby Grand is 13 inches overall. An important in radio Expansion and stabilizing of the radio development The diameter of the bell is 9 inches. reception is announced by the Reich - industry have resulted in the reorganiza- mann Company of Chicago, in connection tion of several of the leading manu- with its production of the new Thorola R. E. Lacault Joins- Phenix as facturing concerns and the issuing of Low Loss Doughnut Coil. This coil, Chief Engineer stocks. These stocks have made sensa- subjected to the most rigid tests, will tional records in the New York and The Phenix Radio Corporation an- Chicago Stock Exchanges recently, due not pick up or absorb any signal other nounces that Robert E. Lacault, E. E. than that brought in through the antenna to the record volume of sales of radio A. M. I. R. E., designer of the Ultradyne, apparatus. system. Its magnetic field is also en- has become Chief Engineer for their, tirely con- The latest re- Corporation, in 'which capacity he will organization plan fined, so that further his inventive genius in behalf of there is no to be carried r to the Phenix Ultra products. His entire through is that spray time will be devoted to the design, dev- following cause inter- elopment and perfection of certain radio the for- ference and mation of the devices that are destined to throw new All- intercou p- light upon radio receiving apparatus in American ling between Radio Corpora- the future. tion, which has various This work, like the famous Ultradyne, taken the parts of the originated from and is an outgrowth of over set. his four years as Radio Research Engi- business of the The new Rauland Manu- neer with the French Signal Corps Labor- facturing C o in- coil is of the atories, where he put to good use his toroid type, pony, manufac- previous intensive electrical studies, de- turers but differs signing various types of radio apparatus of the greatly from largest selling and instruments, working on the first line of radio all other short -wave radio compass equipment transformers in coils of this used at the front in 1915, also on the ear- B. N. Rauland type in that liest wired radio and aeroplane radio the world. The shows ex- new company is headed by E. N. Rauland, it equipment. in radio manufacturing tremely low losses. It was designed by AIr. Lacault was one of the first ama- one of the pioneers Frank Reich mann, designer of the Thorola teurs in France, his radio experiments and their application for a license to and Thorophone loud speakers, and dating back as far as 1911. In the manufacture under the radio patents marks the first step of the Reichmann Research Laboratory of the French Sig- held by the United States Navy has Company into the general field of radio nal Corps-Mr. Lacault worked on the been approved by Secretary Wilbur of manufacture. TPS Ground Telegraphy System, a the Navy Department. Two types of the new coil will be put wired radio system used for direct and Important extensions in the business on the market; one to be used as a coupler instant communication between different of the company are planned immediately. and the other as a radio frequency radio compass stations, by means of Especial attention will be given to the transformer. They will improve prac- which the positions of enemy stations research laboratory work. tically every kind of circuit and are a were found. Forty thousand shares of All- American distinct advancement in radio. In recent years, Mr. Lacault worked stock were offered to the public at $26 a on radio telephotography, also on trans- share. It was oversubscribed six times before being listed on the Chicago Baby Grand Reproducer is mitting pictures by wire, while assisting and Mr. Bolin, the French inventor. This Stock Exchange, it was bid up to $36 a Unique Speaker experience, extending over a period of share. The statement of the company The Grigsby -Grunow -Hinds Co. of many years, gives Mr. Lacault a wonder- shows cash assets of nearly $550,000. Chicago announce the addition of a new ful background for unusual development Mr. Rauland started the business as "Baby Grand" Model to their line of in his new connection as Chief Engineer the All- American Electrical Manufactur- Majestic Reproducer loud speakers. The of the Phenix Radio Corporation. ers. In 1922 it was incorporated as the Baby Grand is a compact loud speaker Rauland Manufacturing Company. Its that retails for $9.00, complete, for home chief products have been audio and radio use. New Sales Manager for Crosley transformers, sockets, fixed couplings The tone Corporation and the well -known All -Amax semi -fin- quality of the Walter B. Fulghum has been appointed ished one and three tube sets. Baby Grand General Sales Manager of The Crosley reproducer is Radio Corporation and began his duties New Steinite Distributors beyond com- March first. He comes to the organiza- The radio world will be interested in pare, accord- tion with a broad knowledge of mer- knowing that arrangements have now ing to the chandising and sales methods, having been completed which enable the Steinite makers, who been associated for many years with the Laboratories, Atchison, Kans., to an- use the well - Victor Talking Machine Company as nounce that the firm of E. O. Jackson & known G -G -H head of their Order Department in Cam- Company, 504 South State Street, Model \VG den, N. J. Chicago, have been designated as ex- Constant In addition to the experience in the clusive distributors of their products T e n s i o n manufacturing side of the business, he throughout the United States and Diaphragm has had experience in the retail business Canada. unit. Volume and many will recall his record of boost- The items manufactured by the is also said to ing business in the sale of phonographs Steinite people, and now made famous be unusual in in the months of July and August and by extensive advertising, comprise the this unit. The horn is made of Du Pont under other conditions. His broad ex- Steinite long distance crystal set, one, Pyralin, which is said to eliminate perience will enable him to appreciate two and five tube receivers, two stage harshness or metallic sounds. the p.oblems of both distributor and amplifier, crystal, crystal detector, and Adjustable volume enables the user to dealer. interference eliminator. 70 RADIO AGE for May, 1925 The Magazine of the Hour New "Fada" Announcement The following is the substance of a ADVERTISEMENTS recent letter sent to the distributors of CLASSIFIED F. A. D. Andrea, Inc., relative to their Don't overlook the value of twelve - time insertions, of five, policy on maintenance of prices. RADIO AGE'S classified adver- fifteen and thirty per cent, re- "Liquidation is being put into effect tisements. Many such mestages spectively. Unless placed through by a number of radio manufacturers. have paved the way to independent an accredited advertising agency, You have our unqualified assurance that incomes. cash should accompany all orders. no such move is contemplated by Fada. The classified advertising rates Name and address .must be in- We have previously written you as re- are but ten cents per word for a cluded at foregoing rates and no gards guarantee on prices until July 15, single insertion. Liberal discounts advertisement of less than ten 1925. We are prompted to write you are allowed on three, six and words will be accepted. again giving you full assurance on this matter because a number of concerns have had certain of their products AGENTS WANTED WRITERS advertised recently by large retail out- and make big NEW WRITERS WANTED -Articles, stories, poem., lets and at an enormous price reduction. RADIO-Join r sales organization scenarios, etc. $13,500 just paid to unknown writer. nay, We want sell tirely new field. (No. bunk.) NOT A CORRE- Among advertisements of this nature ed sets and parts made by the leaeding nul- SPONDENCE COURSE. Moving picture industry and which have recently come to our atten- facturer.. Widener of Kans.. City makes $150.00 crying for new original material. YOU weekly. You can do as well or better. Write today mag- tion, the names of a number of prominent Wave - CApublishersN DO IT. We buy manuscript. for books and for catalog, and discounts. Name your county. azines. Send self addressed envelope for list of 100 who in our land Radio Company, Div. 52, 1027 No. State St.. Chi - subject.. CALIFORNIA STUDIOS. P. O. Box 697, Lm radio manufacturers, opinion cage, III. Angeles. Calif. should readily recognize the need for MANUFACTURER'S AGENT calling on Radio-Elec- constructive action at this time rather trical FACTURE 'S and vicinity. has opening for 3 INVENTIONS than resort to dumping of surplus, additional lines carrying volume business, 1804 McCormick Bid., involved. to large jobbers. Edelstein, WRITERS-Cash in n your knowledge of radio by merchandise, have ,been Chicago. writing for Radio Magazines and Newspaper Supple- "It is our firm intention to continue ments. Write up your radio experiences. your new AGENTS-WRITE FOR FREE SAMPLES. Sell Madison your knowledge of broadcasting stations to limit our salesf exclusively throughout -Better-Made" Shirts for large manufacturer direct to artists. Experienced authors will correct and improve authorized jobbers and to refrain abso- wearer. No capital or experience qu ired. Many your ipts-make them typically professional earn weekly bonus. MADISON MFGRS., 501 work. FREE Criticism and Advisory Service until your lutely from any price concessions to Broadway,d manuscript de- large retail We believe a jobber manding fiction daeÌ g wtraio..ih dp`a H outlets. Is YOUR OPPORTUNITY to profit) Send for FREE who has invested money in our stock HELP WANTED booklet, "How You Can Sell Your Mnuscripts." Willis Arnold and Associates, 210 East Ohio St4 and has merchandised our product along Chicago, Ill. lines is RADIO SALESMEN and SET BUILDERS -We need authorized entitled to proper you and you need ue. If you . reliable and well NEW IDEAS WANTED -Well known Radio Manufac- protection. We believe a dealer who in community, a will appoint you our known your well turer whose products are nationally advertised and sold has purchased our merchandise from our representative . ursh you with standard everywhere wants new Radio device to sell. Will pay and at that will enable you advertised sets parts prices for cata- outright or royalty for idea or invention which is really jobbers is entitled to a clear path in to sell at handsome profit. Write at once new and saleable. Address: Mr. R. F. Devine, Room log and ,ales plan. Waveland Radio Co., Div. 53. 1027 1101, 116 West 32nd St., New York, N. Y. its sale to the user and should not be N. State St., Chicago, Ill. hampered by undue competition which RADIO TUBES must result from price reductions through FACILITIES large retail outlets. To the best of our MANUFACTURING SPECIAL Mstertone Radio tubes all 51.85 poste paid. Nangle Co. 601 Washington Beul.Oak Park, Ill. ability we will guard against any such AN OLD AND WELL ESTABLISHED MANUFACTUR- ING COMPANY IN THE MIDDLE WEST WITH LARGE retail outlets offering our merchandise WELL EQUIPPED PLANTS AND UNUSUAL FINAN- AGENTS on a basis which will create any such CIAL RESOURCES. DESIRING TO ENTER THE RADIO FIELD WILL CONSIDER THE MANUFACTURE AND 90c an hour to advertise and d' bute samples to con- unfair competition to our regular deal- SALE OF RADIO SETS OR DEVICES OF OUTSTAND- quick for territory and particular.. ROYALTY BASIS. eAsumer. icaProducts Co., 2130 American Building, Cin- ers." BOX IA, RADIO AGE. cinnati, Ohio. ADDRESS Radio Show for Man wanted for this territory to sell wonderful St. Louis value men's, Children's shoes direct, sav- in RADIO ing consumer 40`:. Experience unnecessary. October TUBE RECEIVING SET FOR $10. Samples Plans are already being formulated for A PRACTICAL riteltoday Thniners Mfg. Co..,, I334C. St., Boston, Mass. Postpaid, less phones and tube. Complete with battery. 18.00. J. B. RATHBUN, the holding of the St. Louis Radio Show pho1067 e., tub5ea,' Chicago. "B" BATTERIES at the Coliseum in St, Louis, Mo., during the week of October 12, 1925. The show Standard oderless radio Jacks. Binding post attach- 100 VOLT EDISON TYPE "B" BATTERY. knocked ante. Double circuit. One dollar bill. Postpaid. down. Parts and plans-complete, $12.50. Lane Mfg. is under the direction of the St. Louis Clinton Seward. Jr., New Pelts, New York, N. Y. 2937 W. Lake. Chicago. Radio Trades Association, of which Three Cosmopolitan Phusiformers. 51 book of BATTERIES FOR SALE- Four24 -volt "Main" St Colin B. Kennedy, prominent radio ludedh FA. Mall,l Triopli "B" Batterie., never used, shipped and ready to wire for $38.00. First der gets the batteries. Address manufacturer, is president. George Box B. Radio Age, 500 N. Dearborn St.. Chicago, Ill. Niekamp is to be director of the show. FOR SALE -3 Pfantiehl tuning units, 3 Cardwell Con- denser., 1 Bradleyometer, 2 Bradleystata. All goods The week of October 12 has been New. Earl Price, Lodi, Wis. RADIO OFFERS designated as "Radio \Veek" as a means 15 to 25 per cent discount on nationally advertised sets of stimulating interest in the exposition. and parts. Ever item guaranteed. Tell us your needs. RADIO CIRCUITS IMPÉRIAL RADIO COMPANY, Delaware, Ohio. Radio stars and announcers from all over the country will attend the show, and own set from proven RADIO SETS. Our prices save you money. Lists free. BLUEPRINTS -Make your The Radio Shoop., Bor 645, East broadcasting will be conducted direct original and up- to-the- minute blueprints. The follow- Liverpool, Ohio. ing are merely three of choice of almost one hundred from the Coliseum, where special studios JOIN THE RADIO Parts Exchange Club. Your parts different type.: (Fee 25e), and exchanged will be equipped. Already HT -1 -3 -Five tube neutrodyne-50e. inspected for the parts you scores of regenerative-35c. need. What have you; what parts do you require? FB-e- Three -honeycomb Write us for detail.. exhibitors have either signed up for. D10-4 -Diode single circuit -25c. Exchange All three of above, for $1.00. The Radio Parts Club, 112 So. Homan Ave., booths or announced their intention of These tested blueprint all de in ily Chicago. doing so. read circuit drawings. MIDLAND PRODUCTS COM PANY, 1413 Hood Ave., Chicago. III. Ask for our com- According to plans now under way, plete list, No. R-31. RADIO CIRCUITS this will be the "National Radio Show SPECIAL FOR MAY of the Great Southwest" for 1925. The Reinert: Radio Booklet, by Frank D. Pearne, fully RADIO DEALERS illustrated, and RADIO AGE, for 52.50. Price of Book- let alone is 50e. Send check, currency or money order to RADIO AGE. 500 N. Dearborn Street, Chicago. DEALERS -Write for our illustrated catalog of reliable Merchandise. ARoa Corporation, readers wish to show their Dept. D. 1830 Chicago, uIllg VOCATIONS approval of the stand taken Make Big Money. Safe and Lock Expert. Wayne I Strong, 3800 Lan Franco St., Los Angeles, Calif. by RADIO AGE against the STAMPS AND COINS Radio Corporation of America, they 158 Genuine Foreign Stamps. Mexico War Issues. RADIO SUPPLIES can do it in the most practical way Venezuela, Salvador and India Service. Guatemala, China, etc. , only Sc. Finest approval sheets. 50 to Ten per cent discount on all standard radio part. by sending $2.50 for a year's sub- 60 per ce t. Agents Wanted. Big 72 -p. Lists Free. from condensers to transformers to tubes, etc. Send We Buy Stampa. Established 20 Years. Hussman for our latest price list. with special bargains on Static- scription to our magazine, or if they Stamp Co., Dept. 152. St. Louis, Mo. eliminators, portable loud speaker., Radiotronss. Ger- man silver wire, etc. RADIOGRAPH LABORATORIES. are already subscribers, urge a friend 1234 Rosemont Ave., Dept. 4. Chicago, III. WANTED to subscribe. We believe the fans Classified ad. copy for are with us. Address Radio Age, WANTED -To complete my set RADIO AGE need the June August, September, October, November. 1923. imams, RADIO AGE must be sent Inc., 500 N. Dearborn St., Chicago. bound or Advise price. Lloyd C. Henning, in by o Arizona.oo May 1, 1925. RADIO AGE for May, 1925 The Magazine of the Hour 71

Solid With the Manufacturers Rubber (Conrinutd fron moor 69) Case Care in Connecting Condensers Meco Introduces New Important Radio Sets Fixed condensers, when used in radio Simplified tuning obtained by two receivers, are not always given the proper dial controls with only one dial to log care which they need for the important are the principal features of the radio work they have to perform. receivers announced by the Metropolitan The placing of hot soldering irons Electric Company of Des Moines, manu- against a condenser will in most cases facturers of the well known Meco Tubes. do one of three things; change the The radio sets will be marketed under capacity; short the circuit or open the the brand name of "Meco" and will all circuit. be of five tubes. Another thing that does not give the Three different models are being manu- YouSave50% condenser an even chance is the using of factured. All of the sets are similar in World 6 -Volt Storage Batteries Y soft iron bolts, which should be avoided operation, circuit and size. One model are famous for their guaranteed ADprovedand for the reason that they will sometimes will retail at approximately $60.00. Quality and service. Backed by Listed as years Standard by draw up too tightly and change the Another cabinet model will retail at nd Thousands ofaSatisfiedU en. Leading capacity. The use of soft iron builds approximately $100. And the period You save 60% and get a Authorities up a temporary magnet circuit. model will priced SYsar Guarantee Bond including Radio design console be at In Writing News Labor- As a means of getting the utmost out of about $250.00. World Battery owners "tell atories, Popular a circuit and to utilize all signal strength their friends." Tbat's our best Science Insti- Ridge The Meco radio sets operate on radio proof of performance. Send your tute of Stand - instead of weakening it, the frequency action, having two stages of order in today. da, Popular Manufacturing Co., 3818 N. Ridgeway RADIO BATTERIES Radio Labor- radio frequency amplification, two stages &Volt, 100- Amperes . . . . $1226 atories, Radio Ave., Chicago, has perfected the "Handy e. Volt, 120 -Amperes . . . . 14.26 Broadcast Lab- of audio amplification and detector. O Volt. 140- Amperes 16.00 oratories and Condenser Clip" to eliminate the fore- AUTO BATTERES Lefax, Inc. When ordered, Meco sets will be 6.volt. 11-Plato . . . . . $12.26 going faults and to make the radio re- 6 -volt. 19 -Plata . . . . . 14.25 u -volt. 7-Plata . . . 17.00 ceiver just that much better. supplied with tubes matched to the set .. Solid Rubber at the factory. This effects better re- SEND NO MONEY Container Jost state battery wanted and H. H. Eby Mfg. Co.'s Patent ception and eliminates a great deal of we will ship day order is received, Now Standard trouble for purchasers and dealers alike. by Express C. O. D subject to Worlda uipmentonall H. H. Eby Mfg. Co. of Philadelphia, your examination on arrival. Storagqe The extreme selectivity of the Meco Extra Offer: 6% discount for Batteries. No of Eby Binding Posts, cash in fall with order. Boy now more l eakag or the makers sets is to the simplified tuning breakage of jars announcement: attributed and get a guaranteed battery at make the following produced by two dial controls. 60% saving to you. yorrottingof oa. "The United States Government has WORLD BATTERY COMPANY issued patent No. 1529244, dated March 1219S.WabasbAve.,Dept. as Cbicago,IlL 10, 1925, to Hugh H. Eby, president Mohawk Corporation to Expand of the H. H. Eby Mfg. Co. This patent posts which The Mohawk Electric Corporation is fully covers the binding to open a new branch office at 1400 we have manufactured and sold for the about have Broadway, New York City. Appoint- last five years. Our attorneys ment of H. G. Cisin as manager of this advised us that if we intend to protect against branch has also been announced. Mr. our customers and ourselves Cisin has been associated with the Mo- infringing manufacturers, the legal tech- hawk organization in the capacity of nicalities of the case require an announce- sales and advertising manager since the WITH better and more ment of the issuance of the patent and started manufacturing the Mo- we to defend company powerful broadcasting the fact that are prepared hawk single dial 5 -tube receiver, and his - our rights. promotion to manager of this important "We have gone a step farther and New York post will not surprise his and with a sensitive, respon- clearly marked the base of every post many friends in the radio industry. Be- sive Telomonic III receiver - which leaves our factory with our name Mr. to make sides being well -known in the trade, and patent number in order Cisin is also known to radio fans as the the fascination of radio con- identification easy. author of several technical works on "We have felt very much gratified radio and electricity. Besides the new tinues this year, regardless by the many instances which we have metropolitan office being established in of the calendar. seen of the fairmindedness of the radio New York, the Mohawk Electric Cor- trade as a whole. After all, Americans poration also maintains district sales Write to Danziger- Jones, hate a fraud. A large number of our branches in Boston, St. Louis, Los An- C, 25 Waverly jobbers and numerous manufacturers geles, San Francisco, Portland, Denver, Inc., Dept. who are using our posts on their sets Minneapolis, Detroit and Cedar Rapids. Place, New York, for book- have sent us samples of various posts The main offices are located in Chicago. which have been offered to them by let, "The Kit of a Thous- unscrupulous competitors. They have Radio Chain and Possibilities." recognized the fact that we were the The Liberty originators of this type of post and have Stores assured us that they would continue to David Kanofsky, President of Liberty buy from us, no matter how many other Radio Chain Stores, at a dinner given steal our ideas of managers TELO S companies tried to by him to his Metropolitan design and construction." and salesmen, expressed great optimism for the future of Liberty. In his re- Radio Loud Speaker Horn Good for marks Mr. Kanofsky hinted that an im- RADIO Portables portant consolidation was under consid- and called attention to the fact The American Hard Rubber Company eration J has come to the aid of the portable radio that the company plans to open addi- +r fan with a Radion horn and phone cap tional stores and that it plans to open to use on a loud speaker and headphone retail radio stores throughout the country. or headphone unit. The horn is small Mr. Kanofsky expressed great satis- enough to be placed in a radio cabinet, faction in the results thus far accom- measuring but 10 inches high. It has plished and stated that he looked forward excellent tone quality and amplifying to the new 6 -Tube "Clearfield," which HUDSON-ROSS possibilities. The horn and the cap are will be marketed through the Liberty an outstanding Wholesale radio only. highly polished, and will make a minia- organization, to prove One of the first and still in'the lead. ture loud speaker out of a headset by success, stating that already the radio Write for discounts. simply screwing the cap over the unit buyer had evidenced a great interest in of trie headphone. The price of the horn this new set, which is enclosed in plate 123 W. Madison St. Chicago is $2.50. glass; hence its name, Clearfield. Tested and Approved by RADIO AGE 3 72 RADIO AGE for May, 1925 The Magazine of the Hour All You Want to Know About Hookups !

F/GORE THREE SCNENgT/C f/QCU/77 p/q(r,pAM y rVBE LOW-LOSS PFbE/vFgAr VF

7/eKtFR 13 F rn 2 c C2- .0002r

.FWVDeav L2 R/-/-es).

C'7 obcarri ßz fl i 5 O + aw A -- Lr' . eAr = Itltl IUII1 :- r s.cw.vo - O rEQr f

Abore is a circuit diagram of a hookup published in the RADIO AGE ANN UAL for 1925, and which has taken the radio fans by storm! Although ii is but a three-tube affair, it consistently "pulled in California stations on the loudspeaker while located less than a mile from two powerful Chicago broadcasting stations, Hookups such as these make the ANNUAL for 1925 a necessity in your store of radio knowledge. Let the Radio Age Annual for 1925 Teach You Radio! IF YOU are going to build yourself a new radio this Spring and 16 FULL PAGES OF Summer, or if you want a new set for your Summer vacation, BLUEPRINTS! the RADIO AGE ANNUAL for 1925 will fulfill your every technical Scores hookups, in in in the 32 -page blueprint need. of tried and true tested every detail the section of the RADIO AGE RADIO AGE Laboratory, are contained in this wonder hookup ANNUAL for 1925, are book of 120 -pages, with its complete beginners' section, 32 -page worth many times the cost blueprint section for beginner and expert, and its wealth of material of the book alone. Yet these actual -color blue- for the advanced radio fan and set -builder. You will find it a worth- prints, printed as an in- while investment if you get your copy of the new 1925 RADIO AGE tegral part of the ANNUAL, ANNUAL and take it with you on that trip, no matter where you will take you by clear, suc- go. It will always be ready to serve as a handy radio hookup guide to cessive steps through every phase of radio develop- solve your technical problems. The galaxy of clear pictures, wiring ment. An invaluable fea- diagrams and isometric drawings makes the ANNUAL for 1925 the ture in itself! year's outstanding radio book! Clip the coupon now before the first edition is exhausted' $1.00 a RADIO AGE ANNUAL $1.00 a Copy FOR 1925 Copy Solna' of the Features How to read and understand hookups. back receivers, neutrodynes, re ex hookups, Baby Het No. 2, a How to understand radio phenomena Wonder Super-Het, and others. Building your first simple set. How to get rid of interference. How to select the right receiver. How to make an amplifying unit. Substituting a tube for a crystal -building the first tube set. How to recognize and deal with every kind of tube trouble. How to amplify any kind of set. Another super- for super Making a reflex set. heterodyne the experimenters. Building your first Reinartz set. Hints on tracing troubles in super -heterodyne circuits. 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 Reinan. RADIO AGE ANNUAL BLUEPRINT SECTION with such AND MANY OTHER UP -TO- THE -MINUTE HOOKUPS AND popular hookups as the aperiodic variometer, loop sets. feed- ARTICLES. RADIO AGE ANNUAL COUPON RADIO AGE, INC., S00 North Dearborn St., Chicago, Ill. Gentlemen: I want to be one of the first to get the RADIO AGE ANNUAL FOR 1925. Enclosed find $1.00. If I am not satisfied with the ANNUAL. I will return it within five days and you will refund my dollar. Name ------_ - -_- Address City _State....._.-- ---_--__---_- 5-25 CHART

TIR el el reir4..r.1 Ampere

69 WHR 22 UV-200 67 WHR 16 2 11V-201A_z 67 WHR 33

2 1 UV-200 611 WHR 22 II/e 1 UV-20IA 69 AR 17 69 W HR 29 UV-201A 3/4 67 WHR 22 oll RII_R_ 11 3 1 111.200 2 UV-201.A 1'/z 5 69 VI, HR 14 -Volt 69 WHR 22 Tubes 4 UV-201A L. 67 W HR 16 613 1 UV-200 RHR 22 :300 and UV -200 I3/ Ioterchande- 3 UV-201A 611 WHR 15 able 611 W71R 22 6301A, DV -2 and 5 UV-201A 11/4 69H UV -30lA areln- 69 W7IR 17 A'BATPRTERY terchanóeable 1 UV-200 613 RHR 19 5 2 4 UV01A 611 WHR 13 411 RHR 21 6 UV-201A 11/ 69 WHR 14 Write today for 69 APR 21 UV-201A 2 67 APR 15 this free booklet 69 IC RL 22 For acts wins cur- 21/ Whether you have a 67 RPR 13 rent a te higher one -tube set or most an mpere.. 2'/ 69 ARI. 19 advanced multi -tube .....o.c..... 69 RPR outfit, you'll find a fund of interesting informa- tion in our booklet. "How to fit a storage battery to your set - 48 IRR and how to charge it." 69 W 6 BATTERY A BATTERNR Y This booklet gives you the complete Preste O -Lite Radio Chart - How to fit technically accurate rec- ommendations covering both "A" and "B" stcce age batteries for every storage batteries to your set type of set. In addition, there is IT PAYS to buy wisely -to select charging. For "B" Batteries, and much vitally important data on battery care and batteries that bring out the best in "A" Batteries for peanut tubes, see upkeep -information your set and are of the right ca- the complete chart at your dealer's. that any radio fan will pacity to give fine reception at find of real value in keep- Special structure plates, high ing his set at its maxi- recharging intervals best suited to porosity separators and scientific in mum efficiency. Write copy right now. your convenience. ternal construction make Prest -O for your The new Prest -O -Lite Radio Lite Batteries dependable sources of Chart tells you how to select such the even, unvarying current abso batteries. The part of the master lutely necessary for volume, clarity chart shown here covers "A" Bat- and distance. teries for s -volt tube sets. Use Prest -O -Lite Batteries are made to either of the two sizes recommended give long, faithful service. They're for your set, depending on the days easy to recharge -and offer you of service you wish between recharg- truly remarkable savings. Though ings (based on the average use of standard in every respect, they are your set of three hours a day). You priced as low as $4.75 and up. See will find the larger capacity battery them at your dealer's -or write for more desirable unless facilities are "How to fit a storage battery to provided for frequent and easy re- your set -and how to charge it."

THE PREST -O -LITE CO., INc., INDIANAPOLIS, IND. New York San Francisco In Canada: Prest,O -Lite Company of Canada, Ltd., Toronto, Ont.

s

* Tested and Approved by RADIO AGE 3t . % >> >">ctt \\t CR \`q-Q. .\í` ;.;,:...,;.,/,i/..,.ilirliir.r,ii;.¡j/iiii!J°!%ijll>iii)>>j)t> ..;;,...,:.;.>>,`;;;\.\>;,L.....K\_\`\,\;»\,.*c,,C,; (/i%'C'!i}i/,`4,i,,%'r.'yïii'!''ríi!%(4:ii¡i'i:'/.iY.i%li¡(i1ir \\`C !4%i'i/!..4/,,,.>,C./.riii.:\>.,\\7I,. i/\i'i.ii\C'.":C': ':':'C!C,i/,)i,7,>G%/ /,1/,i.4iN!'/!!i, > i\\\\:+\i,\ll ,`/,/./../,./.%li //, %%%%/./ 1/i/i.,/ // ////(/, ,i-a,...\\,.<..\.,, .:.,«,ii` .;\<,\...\,.:.,'»4 >a.\,C/C?>.çiï:i>>ïiii>iii:iii;%i\,iiiii>%!¡ì)iy ,<\.<

ÿ { . i/w. i...,,/i,. . ,.., /> % !'%C,.. /.: ` /i. ,t" / : cv \-C\\`\'\ i\\.. \ `c<<`l\C\ \ \ \<'`\N\\ 'c«%, írir'.'i' ï'/'%:/,%i7%% \ : %'i'ii'''>2 N2/7',2//),''',-;"/c:." ii>>i% :ilii!¡i:%:iii ¡/ > >`!\\iG!i\;/\.:.ii/i;.j\...;;::.:< rl7N//.',"/i'.'i. /i/!i/ii.i;i:i;i!%/ii``i%(i\;:c:.:`%`>.`; ;`ii4%%!`!/i;lií;. .; <<..;;ÿ>j\1 /ii,/iii4`!r.`)... \j`?i :>A\,''/?,>.,>,-)-,,),\C``, ÿ\\;j\:.\\Z.\\,'\ `r!:.i//!i j>\:-j,\ i`i>?4>4;7"?. `\ ::;::\.r:,\:,.,.«:,::'.....<:;:\\..::,<,$5:;,,:.::.::,)çs:.ç,r;% / /tf./ ;-,.'7,s-r,>2./,\ /r.j`,iÏ./i!`/i/1,'./r\ %,i¡,.!ii%/i.i./i/,.ri4\:;?j :; ¢i .,k:.íi 'c 1),L'': ' `¡\(4i1.9i>i2,.i,\\>>i`ií.::!°C:%<<<<¿'i.r.../,,..í i\e\(?r ,6(\ti : <>»Ì\>iNiilllii\\`ÿll<`al\\í%i;%!(%' 1\\.` \\\ /Cl<:(C¡\i'!cC; A \\\\,» % ri,/`i.i/,/.:4ci/Z(/. C:(Ce%/ ( /(( li9iii \\, !iiir%ir, `Regular ,/y,;;».% i , ,,'; ,;,.r,.,. ,i;,,,. %sia J)i\\" ;':;.,,,<<. «, c< < . »>?`\`>.,>. > »\;)>>, '',%/!ii` í;ir > r/i,G'/.:.:',::'/%iia/5'/..`>r / ./,l ,;7 ;>,. \.K\.l%%i >/ ) i7,,S'%% i'i ;»%i>J'?>,'J>% />%'>liii7»'. ii '%)/%%7%>%%%>>>? i(.,% (./,.C,. .i c/. /,,.i./,i,,?i i.il.C:',4W. /.,, ci<(ir (///,..i,;» Cáv.. ''\'!: \. ii>ï)% >./\>\t\j:\\ñ vv />>/%>/! )ij)iii >;.> i>1ii>i >j, >>iü/ /r;%) //, c' /rCii`«.:.:..y1, , /.i /.j i,.,,.'.'/.í, /. ;\`.:`j:.:;.`....<,`%/ii%.í/l:¢/ i4%/%',"\ /,>)\ j '% i 'íi.ii%i1/,\ <<<<\<1 / Special ' <'. ;e.,.>,»>»>,>., , , ,>->w,.,'>,>>>,>.,, ,,.'\,,;;i ,// ... .:,,: ormerlr 5 :\;., ; ,,, «' ....:\(5,"// ,\.,..:,<<,:;:,;,>..:.,.,>,;>> ,'.' ''/.i%¡ri : i'i:iiï/i/¡.%(/,(.i%.I _ -__-_. --= __ Ar - V/./Yi - \ \/ \<< - -. = \Z ii'., , ä,u. ; ,<<,, ,,,,<<;., >>: .o2 ;., .,;,;;, ;;,>\,,,,,,,' 0 o' »,, . _ r . , \: . rmerltl7s = 'Ç >;>>>","\ ` . ,,<<.;. , ,,,,;/,. . .,. _- _ ° ® ;,.ir _ - ,w',». ' / -`--> / i, í>i: -:ri /,;: r .,i.,.. ! r/i .,as,,. \.\`cC\>,%7:%ii%'i./i//.4.ii`\,.f ^^!+ i e `: i', @!J7 e »ÌW: .i,,'/.í!`,`\C :4'!ü ¡i. i:.%. ;; J .....,.%:;:,%,»;;.>!, Z . . . . , . \`\ ; ; , ..,/.>,>>!,>.>`..-\\\ ,,.,, .' / r ---- - ; : , 'iií.'.:i:,.,.,. /i .),,i;i'>,i>i",.íLi/.:%OS:'c:: \,..`.' ,.,,.,.,,,>>>,>>),``\CS, ï,,,,,,,,,,-,<<, ,,,,,, , \\,, ,.. :`'' ;,>>;,; ree Tubes ;,>>,>,;,,,,,,,. ,,. \.\\,:.\ : >,;.\ :. \:,.\. \\\iï/,<<,,í,>.'<<<.;;;,:,?,/t,.<< : ..`: ,<.,<<'-: ,>,,,.,;... .,;. :\ >>.>. >»>.:\. ,>>=; \ Do the worhof :,,,..\\\\, :: :-".,; ,, ,ì,12,->,>,;>»2,;>:: <,\:::: <::,,cc<<,. r,,.;" :;:>>>': .\,:.e %;;,/>>;,,,,> .. ;,%,; :; ,,,., <:r;:,.. Five orSix <\,,$,\ ,, ''!;',";,V.,/:, ..:. J>.d,;,>,!-r,. ..7-,,,,,;>,> / :.LC<:;:':: ::«z >,.>, ; )¡¡i;?;jii;7iji¡,,ii%i::\' ii\i\iiiii %í i¿y ;%üç\>f ,,>;;:.,;\.,;,,,:;;:.`,,,,,,,><;:,.>,,,,, i! in the ;.,. ...,<, >>»; `>; l s' ''.>,ii%i'i/ri' r ..i,Jii:,ii l, r ilii,i i./1...'/i//\<\<<..`,...::. (c< '' i>/l'li.)v<<\«\ i\üvi/:!:''/,5%;;/, , iì \:í°>iiií3!%:i'i5:i\>I`Ii%7%%>>J?>>i>i.c: . .. i>>?9.\.\ i i/' :i. íïi i' %,«...... <4.,.-4 < <,..« ,<( rir rn ,'...<. `»a;\.<<.<<<\:-k.. «.`..,<;\\.,, \ i >\,.,,r;< > )\)\,\\\\,. \ \`»\i .,ai i,>>,i>>i%%i..)),,i\ ;, i7v )\7-\`! i/,;l/./ , )iii»ri.,l,',¡\ j i¡)1;,"i»ï/i)i . c .cc < LcC.. «,c',cLic<::L/:jt::/i,>>>>> »,; ....\.\:,>,>>,>> >,';. ,%..2-.40,').'9,'/N.:.,> \.' : > >,;. ,;,>>>>,> » > , <<.<<<2c<<:c<...r;«<.,c<;:.;<;<;(<<..'?c<<;<<,(':;>liJ">>i%>1>i>)!"%\rS',.,. ,:::..; :`,. i>><: :<;< :'/'::> 'io%'!%':z)//>>/%i?ii>i%%iJ>j>))ii%i:': <«<\<\r<\\,`<\L%.<<\\ .. «<<'\«(L\ \C\<\ «\\i,`>> >,,,,;>>,;,>>,>>;:;>,;.,,,,;,> ,>>>,;>>>,;;; ;;>>>/y;,,>;;,J:,,,,,>>1,;,,.>>-,;,,>,,;,;;,;,>>,; ' ;;,; ;;/.;. ::.> >\ÿ , The recognized outstanding achie gment in radio is the ecomical to operate. The straight fron Trirdyn ', i)>i POWEL CROSLEY. JR., President .? ¡))' :,i>í : 363 Sassafras Street - - - Cincinnati, Ohio ,;,,>,,,,;,,>`\\t` Crosier owns and operates Broadcasting Station WLW 7,),,,, >>- ' \\\.j.iGí4i/7. i.`.O\\\1\\\ i,r »\\ \`\'\\\¡. `\ \ \ .:)\i1%»ji1% `\v Ì~\`\il)\»,-,,,>,>.>.>, i4.,./... % ii .i!i,>/r.,/%,!/,%%/,, ,/r.li .i/ ,/,/:,, ;%/,../i, \\\.Q\% ,/.44.4,,,,,,,,K,,(4,..,... j: i ii'%ii \\ i i \ ii i /i i,i . . ifi. /,.ii,. \

x Tested and Approved by RADIO AGE