Blueprint Section Every Month Built As Only B -T Can Build "No condenser is better than its bearings," -and no other bear- ing made today approaches the mechanical efficiency of the B -T "Lifetime" bearing. You can pay more for condensers but you cannot buy as much. That's why we print on every carton If you don't find it better send it back" The B -T Straight Line Frequency Condenser spaces stations evenly on the dial according to frequencies when used with B-T Inductances. No condenser, regardless of advertis- ing, will give straight line results except with the particular coil for which they are designed. The B-T S L F follows the design and mechanical construction of the B -T "Lifetime, " -leader of the world for the past eighteen months. In buying a B -T product you know you have an original and not a copy. For your protection we caution you to avoid imitations. Type S L F -l7 plate, .00035, is $5.75. The B -T Universal Socket eliminates adapters. It takes the present type and the new UX tubes. You may change to dry cell tubes without changing sockets. Positive, side-wiping, spring contacts insure results. Price-75c. The B -T `Euphonic" Transformer Euphonic, -"pleasing to the ear, " -is the only term that ex- presses the matchless qualities of this new product. Its Universal mounting feature, -exclusively B-T,--is the first real improvement in transformer mechanical construction since broadcasting began. The mounting legs snap into position readily in either position. Either side may be placed up- wards, -the terminals may be brought where you want them and all crossed wiring,-a most frequent cause of howling and distortion, eliminated. Fully shielded, black enamelled,-Gold and Blue seal. Two ratios 2.2 to 1 and 5.9 to I, -small enough to be compact, - Large enough that adding more iron would be wasted material. Just as much superior to other transformers as every other B -T product has been. Price, Low ratio $5.00; High ratio $5.75.

The 8th edi- tion of "BET- Send circulars on your Audio Transformer, Universal TER TUNING" Socket, Tuning Control, High Resistances, -Toro- we guarantee to style- Transformers and all B -T products. The B -T Tun- be the biggest Send "Better Tuning" 8th Ed. 1Oc enclosed. ing Control 10c worth you is proving to be prob- ever bought. It I would be interested in a complete set. Send in- ably the most popular covers many live formation item We ever built. We have been greatly subjects in a surprised at the num- Name ber of people who go way that is pe- to the trouble of writ. culiarly differ- ing us letters after Address trying one. ent. Send the Price- P$2.50 coupon today. BREMER-TULLY MFG. CO. "Pioneers of Better Tuning" CANAL AND HARRISON CHICAGO RADIO AGE for October, 1925 The Magazine of !he Hour I

1;1/4,~Radio" s

Easy to Become a RADIO EXPERT at Home in Spare Time of all ages from youth to settled middle - Big Jobs Waiting in the Radio age. Success does demand training in Business Radio and the N. R. I. course gives you the training necessary to Success. Proof that Radio Pays IF YOU are making less than $50 a week-if you want to get into the Up-to-date Receiving Sets Given with Course Sae What These N. R. I. Men Are Doing big pay class in the world's fastest You learn by doing -through the N. R. I. Course. growing Industry --get into Radio- All materials and equipment necessary are fur- Boys New Car With Earnings nished you along with your course. You are sent age NOW. Coupon brings you full informa- receiving sets to build and install -real sets for Anyone, regardless of is a prac- or sex, should have no trouble tion. experimental work and pleasure. This in mastering the tical course that teaches you to get the practical Radio from Big jobs are open for trained men, in results that big pay jobs demand. N. R. I. course. I am at Pres- every section of the country. Radio man- ent employed as Service Man- Helpful Employment Service ager for the Geo. F. Dent ufacturers distributors - dealers - for - We I am are constantly in touch with openings Radio Service Co. and broadcasting and receiving stations - trained Radio men. The men we train get first sti I taking the course. railroads and steamship companies and chance at these fine jobs through our Free Employ- I have had great success When you selling, building, repairing and branches of the Government, need ment Department -at no extra cost. installing all kinds complete our training we help you until you get of Radios. At present I am trained Radio Experts NOW! Oppor- the 'oh you want. getting a salary and commission which, although tunities are open everywhere for men to I have only been with the firm for 3 months, has enabled me to purchase a new car. go into business for themselves as Radio Richard E. Jones, Bay City, Michigan Experts. The pay is big. Thousands are now making $50 to $250 a week in Gets Own Manufacturing Radio. This great industry is making Business new millionaires almost over night. As you can see by our letterhead. Mr. Bartlet (one of Learn Quickly at Home by Tested your graduates) and I are in Method The coupon below will bring you the business for ourselves. We on ever build 6-tube radio frequency most amazing book Radio, sets and have a ready market You can become a Radio Expert quick- written. It will open your eyes to the for them. This was only made ly, and easily, in your spare time at home, opportunities for you in this establish- poeable through your course. Your instructim . with the help of the National Radio In- ed, big you how to and service is a great help. It is impassible for pay field and tell me to estimate its value in dollars and cents. stitute- America's first and largest home become a Radio Expert in your spare I think Radio offers better opportunities than study Radio school. This famous, tested time at home. It has helped thou- any other field. course makes Radio as simple as ABC - sands of men to success in Radio. Allen N. Birteil, Knox, Pa and so fascinating you will scarcely real- Important: We have a Special Lim- ize that you are mastering one of the ited who quickly. Makes$50 to $80 a Week More industries. In a Offer for those act Your course leads so much world's most important Mail the coupon or write a letter further ahead than practical few short months you may become the NOW. electricity that there is noth- Radio Expert of your town or wherever ing left to say. Since I took You get the benefit your course I have earned you wish to locate. National Radio Institute from 150 to 680 a week more. of our years of experience and you Dept. 53MB, Washington, D. C. Preston Fowler, Gordon, Neh. learn Radio RIGHT when you learn our way! Get this Increases Pay 160 Per Cent I was just receiving 13.00 This Is The Course That Pays for FREE BOOK per S hours when I enrolled with N. R. I. and now I am Itself receiving 11.00 an hour (160 per cent increase). That is \ \'e mean every word of it! We have where N. R. I. put me. The developed the famous method that course bas been worth 32500 a makes it unnecessary for your year to me and in another In- year it wi I be worth $3500 a year. training to be an expense. Andrew M. Shane, Latrobe, Pu. stead of making any man "scrimp" to get his training, our system tO makes your course pay you re- "%leN,IR. 0- turns practically from the start. When you learn our proven wII M Ill I ( I I II IIIIIIIIIIIIIInIilÌlÌlllluillllllllu 1IWIlpI way your course will pay for itself, NATIONAL RADIO INSTITUTE, Depl. 53MB, and more -much more! Get the Washington, D. C. Without obligation send me your book, "Rich Re- details of these amazing methods. wards in Radio," which tells all about the opportunities in Radio, how spare time study at home will qualify me Don't Worry About Age or = quickly as a certified Radio-tncian so I can get one of Education these splendid positions, and how your Employment Service helps me to secure a big pay A. It makes no difference what Name Age...... is or what your pre - your age St reel x ious training has been. Radi., i+ a field in itself. It calls men y.. State aF Tested and Approved by RADIO AGE 2 RADIO AGE. for October, 1925 The .lta2azine of the hour

A Chat With the Editor The Magazine of the Hour BIRDS in our temperate zones Established March, 1922 are breaking up housekeeping WITH WHICH IS COMBINED RADIO TOPICS and preparing for their an- nual flight southward. Hollyhocks Volume 4 October, 1925 Number 10 are flamboyant along the garden walls, like glowing, dying embers. There is a flaw of wind at sunset CONTENTS which breathes cool oxygen into fragrant bonfires. Soon the frost Cover Design by A. P. Mehluln will be on the pumpkin and the maples will be ablaze. Auto-Transformer Coupling 7 By Roscoe Bundy Long evenings are coming, when Some Facts About Quality 11 the fireplace will call again and By Brainard Foote there will be mulling cider and beckoning book shelves. Where the Power Comes from _ 14 By E. J. Felix And radio. A Distortionless Audio Amplifier 15 That is what we were coming to. By E. R. Pfaff What joy of listening this fall and An Improved Slide Wire Bridge .....17 winter! More powerful stations, By H. Frank Hopkins better broadcasting technique, im- proved programs, superior receiving Electricity -the Life of the World 19 By Frank D. Pearne apparatus. It has been the busiest of summers on the air and it is A War Against Radio Fading 21 to be an epochal 1925 -1926 season. By S. R. Winters The radio industry has found Experiments with a Box Kite Aerial 23 itself. Radio listeners have thrust aside the doubt and inexperience More Super Stations are Coming 24 of another day. The listening RADIO AGE "What the Broadcasters are Doing" millions know exactly what they Studio -Land Feature Section 25 -32 want and how to get it. RADIO AGE Blueprint Section -Dual and Single This magazine of ours has been Controls 13 -41 on the sentinel line watching four By John B. Rathbun such seasons of good reception Pickups and Hookups by Our Readers 43-44-46-48 send forward their outposts to prepare for a new drive against Corrected List of Broadcasting Stations 66-68 -70 dull care in radio time. Our modest sixteen-page pamphlet in the early spring of 1922, in keep- Radio Age is published monthly by RADIO AGE, Inc. ing step with the march of radio, Member: Audit Bureau of Circulations. has moved forward to an enviable 1 position among publications. Publication Office, Mount Morris, Ill. Address all communications to RADIO AGE, INC. \Ve believe you will like this Executive, Editorial and Advertising Offices October number of RADIO AGE. 500 N. Dearborn Street, Chicago, III. We assure you that it is our sole aim to make each succeeding FREDERICK A. SMITH, Editor FRANK D. PEARNE, Technical Editor number more helpful and more M. B. SMITH, Business Manager interesting. Judging from the public's generous support, we have Advertising Director not labored in vain. We hope HARRY A. ACKERBURG 500 N. Dearborn St., Chicago, Ill. the magazine will be your com- panion these long evenings to Eastern Representative come and that it will continue to DAVIDSON & HEVEY, 17 West 42nd St., Neu York City be a constructive factor in the Pacific Coast Representative magnificent destiny which awaits V. M. DEPUTY & ASSOCIATES, 515 F. V. Braun Bldg., Los Angeles, Cal. the most popular of all sciences. Final Advertising forms close on the 20th of the 2nd month preceding date of issue Vol. 4, No. 10. Issued monthly. Subscription price $2.50 a year. October, 1925. Entered as second -class matter at post office at Mount Morris. Illinois, under the Act of March 3, 1879. Convriob,. !8M, by RADIO AGE. Inc. Editor of Radio Age. RADIO AGE for October, 1925 The Magazine of the Hour 3 ECONOMY No ONE size or type of battery can be EVEREADY HOUR EVERY TUESDAY AT 9 P. M: economical on every type of receiving Saetera Standard Time For real radio enjoyment, tune in the set. That's why Eveready Radio Bat- "Eveready Group." Broadcast through sizes and stations - teries are made in different WEAP Nee York WSAI Cincinnati W1AR Providence WWI Detroit types -so that every radio user can WEEI Boston WCDD I Minneapolis W F I Philadelphia t St. Pau( by WGR Buffalo WOG Doren'rr enjoy the economy that is to be had WCAE Pittsburgh WCTS Words r fitting exactly the right Eveready Bat- tery to his receiver. For owners of sets with five, six, eight or more tubes, and power amplifiers, there is the extra - large, powerful and unusually long -last- ing Eveready "B" Battery No. 770. There is an Eveready dealer nearby. Manufactured and guaranteed by NATIONAL CARBON COMPANY, Iec. New York San Francisco Canadian National Carbon Co., Limited, Toronto, Cntario

^u. RADIO oar u + EVEREADY

E VE g.EAlfY 1} Radio Batteries COLUMBIA they last longer IGNITOR 1) RY CELL FOR , RADIO, IGNITION A AND A +ENERAI PURLLPO665 INSPICTWW TYTao MILIARIA NIDONAL CARD fiµ¡

No. 766 Eveready ? q -volt Columbia Large Ignitor Horizontal A Price Battery, $2.00 the )oven ly cell Joe ail radio dry cell tubes volts

No. 770 45-volt Extra- Large Vertical Prue $4.75

Testas tasa' Approved by RADIO AGN x l RADIO AGE for October, 1425 The Magazine of the hour

T JEREWITH are some facts about the extent that the gyp would have to go out of radio gyps. A gyp is a price- cutting business. Not so. Barnum said there was one 1 sharp shooter who fires broadsides of sucker born every minute and one time or sensational advertising at the radio public, another each one of them lines up at the offering a standard product at less than the counter of the gyp. The best that can be done regular retail price. When a customer is at- for the situation is a continuous presentation tracted to the gyp's store by such advertising, of the facts, showing the advantage in dealing the customer finds that the gyp has sold out his with radio merchandisers who buy honestly, advertised line and proposes to sell the advertise frankly and sell fairly. customer something else, equally as attractive The radio experimenter or complete set buyer. in character or price. Or the gyp may sell him may establish himself in a safe policy by same adopt- the standard product advertised, at the ing a rule that he will buy only from those time neglecting to inform the customer that it whose advertisements appear in reputable is an obsolete model or type, and is worth far less than the amount, that even the gyp is periodicals. He may be sure that if the period- charging for it. ical is of good character and is building for a Your gyp will announce in his advertisement long pull, its publishers are bound to carefully that he has 500 Excella Loud Speakers for sale scrutinize the advertisements as well as the at one half the regular price. Investigation editorial material which is submitted for pub- will show that he actually has perhaps a dozen lication. Excella Loud Speakers for sale. He probably At the same time, manufacturers and dealers has had a lot of trouble in getting his hands on necessarily use care in the selection of the that many. But he announces a large stock periodicals in which their advertising appears. so that customers will come to him with con- What would you, as one of the buyers who are fidence that they will be able to get the turning $400,000,000 into the coffers of the Excella, no matter though they may arrive radio industry this year, think of the advertiser several hours after the doors open on the who would permit his selling message to appear. "great sale." Failing to get the Excella, the in a magazine which, for example, was notori- customer looks around. Probably he buys ously competing with its own advertisers by something else. He has been confidenced into establishing manufacturing or retailing enter- the store and there are plenty of high pressure prises and publishing advertisements of those clerks in the place to see that he does not get enterprises under names which attempted to out before he is sold. conceal the magazine's connection with the Gyps are not peculiar to the radio business. advertiser? Or what would you think of the They have been blow- torching their way into sagacity of a manufacturer who would advertise legitimate lines of trade ever since the time of his products in a magazine, which in a single Tubal Cain. They come and go like the oily issue would print page after page of advertis- gentleman who manipulates the three shells ing announcing cut prices on standard products and the pea at county fairs. They rent cheap which established and reputable manufactur-

store locations and decorate their windows ers were advertising in the same magazine at . with enough astonishing price propaganda to higher, though perfectly fair and reasonable, make even a wary man stop and look. They prices? What would you think of a manu- are not welcomed into chambers of commerce, facturer who permitted himself to be tempted) business clubs or dealers' associations. Much away from reputable, honest-dealing magazines of the merchandise that is actually what they by the gyp lure of a publisher who slashed! represent it to be is obtained by them through advertising rates for certain accounts and mitt- secret sources. It bears the finger prints of represented circulation figures in order to gilt unethical business. the customer in? Sagacious advertisers do not One might suspect that after a few lessons fall into such traps. Buyers of radio equip- the public would become educated to such an ment may profit by their example. 12.:1.UIO :1(:1:: for ((tether, P)25 The .11a,arilfe of ¡he Hour í Radio drafted Bakelite so all could listen -in To make available for everyone, everywhere, the marvel of radio reception, radio engineers required an insulating material possessing a

1 unique combination of properties. l sV\ 4. "h./i; Bakelite alone met the need. It combines high insulation value with strength and light weight. It is easily formed into the many shapes required and will not warp, shrink nor swell. It will not absorb moisture and is unaffected by extremes of heat and cold. All "Polyplug" of these properties and the beautiful Polymet Mfg. Co. color and finish of Bakelite are permanent- - unaffected by time, use or climate. So "Radio drafted Bakelite," and today it is used by over 95% of radio set and parts manufacturers. Dial The Bell Mfg. Co. Make sure that the radio set or parts that you buy are Bakelite insulated, for good insula- tion is essential to clear reception.

Write for Booklet 31 BAKELITE CORPORATION 247 N. Y. Rheostat Park Avenue, New York, Yaxley Mfg. Co. Chicago`\ Office: 636 West 22d Street

Aristocrat Dial Kurz Kasch Company

Condenser Sanganro Electric Co :r.

íèl t . f ! [=

Condenser lil - BremerTully Co

Bakelite is aoesdudve trade mark and can be treed only on products BAKELITE made from materials the n the registered trade manufactued by mark for the phenol Bakelite Corporation. resin product menu. It Is the only material lectured under pat. which may bear this eras owned by the famous mark of acted. lmR KELI Bakelite Corporation. THE MATERIAL OF A THOUSAND USES t Tested and Approved by RADIO AGE G It:\I)ll) AC.1: for (4-tuber, 11)35 771e° alagvaine of lJre Hour

Whether you smile or cuss depends upon the service behind your Radio

WHAT is this radio service which The handy man who can fix any we claim is so necessary? radio simply experiments until he Openings for a Few Do you drive a car? locates the trouble -such a method was disastrous to the auto in former More OZARKA Do you ever have little things go days -it is disastrous and expensive wrong with it? in radio today. It is not sound. Factory You have become so used to minor Representatives troubles that you don't condemn the Ozarka instruments are sold only by car on which they occasionally occur. Ozarka factory representatives, men OZARKA Incorporated, is now entering who are factory trained in sales and its 4th year. From a beginning with one No- engineer, one stenographer. one sales- service, men who sell no other radios man-our present president, theOzarka organ- You go right to a service man -a but Ozarka. ization has grown to over 3,100 people.There man who knows your make of car. must be some good reason for this growth. You don't go to a handy man who These men don't pretend to know Ozarks instruments have made good-they have all radio more than met competition. Ozarka representa- claims he can fix any car. about but they do know all tives have made good not only because Ozarks there is to know about Ozarka -isn't instruments were right. but because they have service, is one been willing to learn what Ozarka engineers were That's automobile and that the kind of radio service you want? willing and capable to teach them -Ozarka un of the main reasons for the auto being usual salesmanship and Ozarks service. the success it is today. Ozarka instruments There are still openings for the right men in this are sold under organization -men who believe in the future of a very definite plan. An Ozarka repre- radio-men who are tired of working for some one The same service condition exists in else -men who want a business of their own. Prove radio -the only difference being that sentative will gladly set up an Oza.ka yourself by sales and willingness to learn and in your home won't exclusive territory will be given you. The man we people don't yet understand it. -he tune it -he want has lived in his community for some time. He won't tell you what it will do -you has the respect of his fellow men because he has never "put anything over" Just to make money. He The radio instrument which never must operate yourself. If the results may not have much money, but he is not broke and requires service has never been built is, at least, able to purchase one demonstrating you receive by your own operating instrument. -it never will be. won't convince you that the Ozarka Like automobile manufacturers, the gives you the distance, volume, selec- Send for FREE Book better radio manufacturers do all tivity, tone and ease of tuning that Radio offers a wonderful opportunity to men who are willing to start at the bottom and build. You within their power to make their in- you demand then don't buy it. need not know salesmanship. but will you learn struments mechanically perfect. what we will gladly teach you? You may not know Nev- Ozarka instruments are built to sell radio. but we can and will teach you if you will do ertheless, like the auto, little things your part. With such knowledge and willingness to themselves bu t no Ozarka is sold with- work, it doesn't seem possible that you cannot make will sometimes go wrong -they are good. Sign the coupon below, don't fail to give the out factory-trained service behind it. name of your county. Better still write a letter. serious to the radio owner but very tell us about yourself and attach the coupon. If simple to a factory trained service man. interested in o ur salesman's plan ask for " Ozarka Plan No. 100." INca R P QR'tti 122 Austin Avenue A 122 Austin Avenue A Chicago, Illinois Chicago, Illinois Gentlemen: Without obligation send book "Ozarks Instru- Gentlemen: I am greatly interested in the FREE book "The ments No. 200" and name of Ozarks representative. Ozarks Plan" whereby I can sell your radio instruments 10-25-122A 10- 25.122A Name Name Address City You'll Know the Man Address City County. State Behind This Button! County State

* Tested and Approved br RADIO AGE A3 SEP 28 1925 ©CI 8668175

RADIO AGE for October, 1925 7'he Magazine of the Hour 7

O®o©O©C1E EA CIICP - U71 Il7r 47®GOEl7

tyre Ma8a3ine the Hour

A Monthly Publication M. B. Smith Denoted to Practical Frederick A. Smith Buainew Manager Radio Editor

L.110 EO1 Il7 l7 1ooa o Cl Cl t3J Handling the Radio Stages with AUTO -TRANSFORMER Coupling

HILE there are a number of ing capacity seriously affects the selectivi- different methods available for By ROSCOE BUNDY ty and always has a strong tendency W coupling the various radio stages, Copyright 1929 toward setting up free oscillations because yet the transformer method of coupling of the low resistance of the winding. An has been almost universally adopted for electro- static transfer takes place be- radio frequency receiving sets. This tween the two coils regardless of the applies to all types of receivers in which Comparing the Many tuning condenser adjustment; hence the radio frequency amplification is used, selectivity is not all that could be de- super- heterodynes as well as reflex Methods of Coupling sired. Signal strength is reduced when circuits and plain five tube sets of the the coupling between coils is reduced, so popular "dyne" order. At one time, there is a decided limit to the practical tuned impedance coupling by means of plate potential and hence greater amplifi- utilization of the incoming waves. variometers or else condenser tuned air - cation results from the increased volt- With the untuned or "aperiodic" trans- core impedances, seemed to be gaining age. The transformer affords a simple former there is less tendency toward in popular approval, but when the neu- means of increasing the potential at the uncontrollable oscillations owing to the trodyne was introduced, the impedance grid of the tube, and hence the amplifica- much greater resistance, but with such system received a set -back from which tion, but it has other characteristics transformers there is no selectivity and it has not yet recovered. Resistance which are not so welcome -the tendency a very great deal of electrostatic coupling coupling, after the manner of resistance toward the establishment of free oscilla- which reduces the effectiveness of the coupling the audio frequency stages, was tions for one thing. . coils. As such transformers are designed only efficiently applicable to long wave primarily with the idea of obtaining uni- reception, but even then, the resistor Capacity Coupling form amplification over the entire broad- type coupler was seldom encountered, NO matter how carefully the trans- casting wavelength without tuning, the even on the super- heterodyne, where it is former may be designed and con - selectivity of the circuit must depend at its best. structed, there is always a certain degree entirely upon the antenna tuning system All modern air -core transformers are of capacity coupling between the primary or upon auxiliary tuned stages which may essentially the same, no matter how they and secondary coils which causes trouble, be introduced. They cannot be "peaked" may differ in the details of the windings and reduces the electrical efficiency below on a certain definite wave; hence the am- or core. They all have a primary coil that which would ordinarily be expected plification is never so great as with the that is electrically isolated from a from the coil. In the case of tuned radio tuned secondary transformers. The iron secondary coil with a magnetic coupling frequency transformers, the inter -wind- core type of aperiodic radio frequency between the two transformer circuits. The plate has a higher current of the first amplification than tube in passing the air core, as a through the pri- rule, and the wave- mary coil of the band covered with condenser creates uniform amplifica- a magnetic field tion is greater, but which in turn in- still the type has duces a current in other undesirable the secondary coil. characteristics. As the turn ratio Impedance between the coils is coupling, both generally greater tuned and aperiod- than unity, the ic, generally gives potential estab- a lower amplifica- lished at the tion than the terminals of the transformer, but in secondary, and certain other re- hence at the grid spects it is the of the following superior of the tube to which they transformer type. are connected, is it is easier to tune, greater than the is not quitesn criti- 8 RADIO AGE for October, 1925 The Magazine of the Hour

Tuned impedance coupling is really the pr -z simplest type, although it does not give IN quite the amplification given by the trans- former. A detail is shown by Fig. 3 where the three tubes (T1- T2 -T3) are OUT impedance tuned by the fixed inductances (L1 -L2) and the variable condensers (C1 -C2) connected across the ends of the C2 inductance coils. Increasing the capacity .. of the condensers increases the induct- \ o .+ym ance and wavelength of the coils so that they can be peaked on a given wavelength just as with the tuned radio frequency transformers. The positive (-I-B) current passes from the "B" battery to the plates of the tubes through olll1l1 o the inductances, and the inductances are -,q t tuned so that the plate output of pulsat- tB `I1i1I101IIII1 ing current cannot short circuit and pass back to the battery. The con- Fi:2 densers are adjusted until the inductance is just sufficient to choke back the radio frequency current at the given wave- cal on the controls as the transformertype, (RF -2) in the familiar fashion, but the length so that it cannot pass through and is less likely to cause free oscillations primary coils (P) are not separately tun- the "B" battery circuit, and at this in the radio frequency circuit. However, ed and are therefore known as "aperiodic point a maximum difference of potential being a single circuit proposition with no primaries." As few as five or six turns is established across the ends of the coils means of controlling the coupling, the are often used for the primary coils (P) so that the greatest possible potential tuned impedance type of receiver is which brings their natural period far is brought on the grid of the following rarely so selective as the tuned air -core below that of any ordinary broadcasting tube through the fixed stopping con- transformer unless unusual pains are wave and therefore the grid and plate densers (K1 -K2). taken in the construction of the coils circuits are not so likely to be tuned into Stopping condensers (K1) and (K2) and in the arrangement of the circuit. resonance and self-oscillation as would must be provided between the plate Again, there is some loss of plate current be the case with a greater number of and the grid of the following tube to through the inductance to the "B" turns. The number of turns and length prevent the "B" battery current from battery, and the ratio is never much of wire on the secondary coils are determin- reaching the grid and giving it a positive greater than unity, so that the voltages ed by the wavelength band and the size bias. If the positive "B" were to act impressed on the following tube grid of the variable condensers (C1 -C2), and on the tube, it would be paralyzed and are rather low. the turn ratio between the primary and rendered useless as an amplifier, for a In Fig. 1 is a typical aperiodic trans- secondary varies from 6 -to -1 to 11 -to -I negative potential is necessary on the former coupling, where the output of the in commercial types of coils. grid for amplification. However, the tube (T1) is transferred to the grid of Owing to the small amount of wire on capacity of the fixed condensers is great tube (T2) through the air -core radio fre- the tuned radio frequency transformers, enough to pass the radio frequency cur- quency transformer (RF -2); Plate cur- the resistance is very low and the rent freely from plate to grid so that rent from (T1) passes from the "B" efficiency is correspondingly high. By coupling and amplification takes place. battery through the primary coil (P) properly adjusting the distance between Radio frequency oscillating current can on its way to the plate, hence all pulsa- the primary and secondary, thus main- pass directly from the plate to the grid tions in the coil (P) are inductively taining a proper magnetic coupling, the of the following tube but the direct transferred to the secondary coil (S) by coils can be made very selective provid- battery current cannot pass. magnetic linkage. A comparatively high ing that the electrostatic coupling is kept potential is developed at the end of the at a minimum at the same time. By Adjusting the Leaks secondary coil (G), and this acts on the having a number of successive tuned AS the grid requires a negative "bias" tube (T2) to produce greater amplifica- radio stages of this type, the total selec- or a continuous negative charge for tion. Tube (T1) receives its energy from tivity can be made to reach a high degree, amplification, the high resistance grid a tube connected to the input (Primary) for each successive stage makes it possible leaks (R1) and (R2) are connected to of transformer (RF -1) and the same to reduce the interference waves passed the grid side of the coupling condensers system is carried out with any desired by the preceding transformer until un- with their outer ends connected to the number of "radio stages." desired stations are completely elimi- ( -A) wire of the filament battery. A In this sort of transformer, the wind- nated. small amount of current passes through ings are so proportioned that a fairly uniform coupling is had over a fairly wide range of wavelengths, say from 200 meters to 550 meters. The coils are wound with fine wire and have a con- siderable resistance, which damps down free oscillations but which equally causes comparatively high ohmic losses and re- duced amplification. Tuned R. F. Transformers BY tuning the secondary coil to ave- length by means of variable con- densers as in Fig. 2, the transformers can be accurately "peaked" at the desired wavelength so that the maximum ampli- fication is secured on any wavelength within the range of the condensers. The variable condensers (C1) and (C2) are connected directly across the secondary coils (S) of the transformers (RF -1) and RADIO AGE for October, 1925 The Magazine of the Hour 9 the leaks to the grid from the negative ratio of the transformer. The total pole of the "A" battery, and the required result is a greatly increased potential amount can be obtained by adjusting the in the grid line at the stopping condenser leaks until the proper bias is found by (K1) that gives high amplification in the experiment. It should be noted that the second tube (T2). As before explained, leaks are an indispensable proposition the stopping condenser (KI) prevents in this sort of circuit and that they must the "B" battery from putting a positive be carefully fitted to the tubes for maxi- bias on the grid of tube (T2). mum results. The stopping condensers A grid leak (Rl) is placed on the grid (K1) and (K2) are not critical. side of the stopping condenser (K1), and I nstead of the simple tuned inductances by connecting the other end of the grid shown, variometers can be employed, leak to the negative filament line (-A), and as a rule the variometers are more a negative potential can be established efficient than the present scheme although on the grid of (T2). The plate output they have practical disadvantages. The of (T2) is then led through the tap point introduction of variable condensers causes (t) of the second auto-transformer (L2), losses which are avoided by the pure and further amplification is attained in inductance of the variometers. the third tube by the same method. A coupling of this sort is less critical The variable condenser (CI) is used to than a transformer coupling, that is, the tune the system to wavelength in the peak of amplification is not produced usual manner. We really have a trans- within a fractional part of a dial division, former, but it is a special form of trans- and for this reason, squealing is not so former that performs exceedingly well often experienced with the tuned induc- in regard to tone and freedom from self - tances as with transformers. However, oscillations. it is less selective per stage than the As the tubes are somewhat critical to transformer coupling, and even with its the resistance of the leaks, an adjustable purer, cleaner tone it is often supplanted resistance is best at this point so that the by the transformer for this reason. The resistance can be just right for the indi- impedance gives a wonderfully pure tone vidual tubes with maximum volume. when properly constructed with practi After once adjusted, the leaks need no cally no distortion or noise, and this is further care until the tubes are changed probably due to the checking of audio ary although all parts of the circuit are or replaced by new. It is not necessary frequency currents by the stop conden- electrically connected. Both the vir- to mount the grid leak controls on the sers in the grid lines. tual primary section (m) and the second- front panel. Many experiments have been made by ary section (n) are threaded through by Complete Auto -Transformer Circuit the writer in the attempt to combine the the same magnetic flux and are magneti- advantages of the transformer and tuned cally as well as electrically coupled. pc,. 6 shows the complete circuit for impedance, and out of these experiments Therefore, with a given ratio of turns use with auto transformers, two the "auto- transformer" type of induct- between (ni) and (n), we can correspond- stages of radio frequency amplification ance has proved the most successful. ingly build up the potential at (B) just and detector. Audio amplification can It avoids the noise and critical adjust- as in the transformer secondary coil. be added to the output as with any other ments so often in evidence with straight The voltage between the ends (a) and radio frequency set, but is not shown here transformer coupling and at the same (h) is now much higher than between as it is considered desirable to concen- time, the degree of amplification is much the primary terminal (m), and greater trate our attention upon the inductances better than with the tuned impedance amplification can be had than with a and other details of the radio frequency type. So far as selectivity and distance simple tuned inductance. The coil is stages. After the previous description are concerned, the auto -transformer coup- tuned by the variable condenser (CI). it should not be difficult to understand ling has been found eminently satis- In Fig. S we have a detail of the appli- the principles of operation. factory in the vicinity of Chicago where cation of the auto -transformer to the It should be particularly noted that interference from local broadcasting sta- receiving set. The output (plate cur- the two radio frequency tubes (Ti) and tions is at a maximum. The volume is rent) of the first tube (Ti) passes (T2) are given a negative bias by con- slightly less than with the transformers through the virtual primary (P) to the necting the ends of the leaks (R) to the but the tone is so wonderfully improved battery at ( +B). The position of the ( -A) line. On the other hand, the detec- that it more than compensates for the tap point (t) determines the ratio of the tor tube (T3) is given a positive ( +) lost amplification. primary to secondary turns or the bias by connecting the leak (R3) to the An auto- trans- positive ( +A) side former consists of of the filament a single continuous battery line. This tapped coil which change in biasing serves both as a polarity is most primary and sec- important, and if ondary. In Fig. 4 it is not observed, is the complete coil the set will be in- (A -B) tapped at operative or at the point (t), the least greatly weak- latter being the in- ened. All of the put for the plate constants given for current. In pass- the units on the ing from ( +B) to drawing will be (t) through a small found correct for portion of the coil, the majority of the turns in the dis- cases, although tance (m) become there is consider- the virtual pri- able development mary of the auto - work yet to be transformer, while done before the the total length '(n ) circuit reaches its forms the second- (Turn the page) 10 RADIO AGE for October, 1925 The Magazine of the Hour

highest efficiency. It is a brand new type by experimental means. With 55 turns mf. were tried, but above 0.002 mf. there so far as I am aware, and promises total, a 0.00035 mf. variable condenser did not seem to be much increase notice- much with further experimental work in connected across the ends of the coil will able. Below 0.001 mf. there was some regard to details. It is intended as a sug- tune it through the broadcast range of falling off in volume, but not a great deal gestion for the more experienced fans wavelengths. As explained before, the of loss. The ordinary 45 to 90 volts can who find pleasure in experimenting with circuit is rather critical to the grid -leak be applied to the grids of the tubes, novel circuit combinations and is not value and for this reason variable resist- although the lower voltage probably particularly advised for the beginner. ances are the best. The approximate brings in distance better than the 90 The total number of turns on the auto - value of fixed leaks is shown on the draw- volts which gives the greatest volume on transformer from end to end of the coil ing, and with the tubes used in the ex- local stations. will be from 55 to 60 on a three inch periments this resistance value gave very If more radio frequency stages are de- tube. Generally, the tap point (t) for the good results. sired, they can be added by repeating connection of the plate circuit works The capacity of the stopping conden- the auto -transformer and leak arrange -. out best at 8 turns from the end, but sers is not critical and almost any ment shown for the first two stages. it will be safest to provide at least three capacity that will freely pass radio Four and five stages have been used taps at 8, 12 and 15 turns so that the frequency currents will be satisfactory. without difficulty in the way of critical optimum ratio can be easily determined Values ranging from 0.0005 mf. to 0.005 tuning, and the quality was little affected

U. S. some time ago by the International has prepared letters of instructions to Radio Representatives Telegraph Bureau at Berne, together with the American delegates as to this govern- Sail for Paris the agenda of the international sessions ment's policy. This policy has not been WASHINGTON. -America's three un- which opened in Paris on September 1st. released by the State Department, and official observers to the International One of the many suggestions made by the may not be made public, but it is said to Telegraph Conference at Paris sailed European Governments is that the sub- express a desire on the part of the Govern- from New York on the S. S. America ject of radio be considered at the con - ment and the private commercial radio last month. The delegation was headed ference. To this it is believed the Ameri- interests, that, if possible, radio be kept by John Beaver White, a retired engineer can government will object, in view of out of the general telegraph discussions of Philadelphia, and included Honorable the special world conference on radio to and that this subject in its many phases Wallace H. White, Jr., Congressman of be held in Washington in the near future. be left for the world radio conference. Maine, and Maj. Gen. Charles McK. At least, the delegates will express a hope The Chairman of the Interdepartment - Saltzman, Chief Army Signal Officer. that any changes made in the present al committee, Leland Harrison of the Although the United States is not a telegraph convention, will be such as State Department, has not attended the party to the International Telegraph would be acceptable to the radio confer- sessions here. In his absence, J. B. convention, the Senate never having ence when it meets here. Obviously, it White, a friend of Secretary Hoover, acted on it, it is understood, its represen- would not be desirable to have matters has acted as chairman of the special tatives will be seated as unofficial dele- pertaining to radio threshed out in detail committee on Paris conference. The gates and granted all privileges except prior to the regular radio sessions. On personnel of the committee includes the right to vote. In this capacity the the other hand, assurance is given by Maj. Gen. Saltzman, and Major J. O. U. S. delegation will present the views of the Berne Bureau that only the inter- Mauborgne of the Signal Corps; Captain the U. S. Government and probably also national radio policy with its commercial Ridley McLean, Director of Naval Com- the attitude of the private interests which and business angles would be included munications; Asst. Secretary of Com- own and operate the commercial tele- if this subject is injected into the tele- merce Stephen Davis, and P. E. D. Nagle graph, cable and radio services, as to the graphic sessions at Paris. That is, the and W. D. Terrell of the communications desirability of incorporating the field of technical side and service regulation and radio sections of the Commerce radio in the international regulations affecting wavelengths, power, schedules, Department; H. C. Moore of the Ship- prescribed by the telegraph convention. etc., probably will not be considered. ping Board; E. M. Webster of the For the past month, representatives of The U. S. Interdepartmental Committee Treasury, and W. R. Valance and W. M. the several government departments in- has analyzed the voluminous report from Greene of the State Department. terested in radio have met daily in the Berne, to see how it affects the interest Technical aides who accompanied the State Department. This body, known as of the United States, where all communi- American Delegation included \V. D. the Interdepartmental Committee on cation systems are privately owned. Terrell, Chief Supervisor of Radio of the Electrical Comm., has discussed the It has filed its report with Secretary Department of Commerce and Maj. J. O. proposals submitted to this government of State, Kellogg, who, it is understood Mauborgne, of the Signal Corps. RADIO AGE for October, 1425 The Magazine of the Hour I I Some Facts About QUALITY

Loud Expert Speaker Tells How Music Use of Without Two Loud Trouble- Speakers some Will Enable Distortion Listener Is Now to Receive The Big Pure High A simple low frequency reproducer to supple- Problem in ment the regular horn type and Low loud speaker may be built from a banjo -mandolin and a Baldwin receiver unit. A long Radio pin is used to connect the armature Notes to the mandolin head. Reception Faultlessly By BRAIN ARD FOOTE

THE general problem in connection cut off thereby. These side -bands are former handles the lower frequencies with entertainment with a loud nothing but wavelengths just a bit quite well. However, the higher notes speaker is, briefly, to reproduce music different from the stated wavelength will be slightly more pronounced in this and voice just as it sounds in the broad - of the station and are directly due to stage. If there is any sudden crackling cast.station's studio. This resolves itself the fact that the imposition of voice or surging of the volume, something is at once into three separate departments frequencies on the camer wave not only wrong with the tube's functioning. Prob- of radio reception, as follows: - has a modulation effect but a HETERO- ably a "C" battery of 3 volts is needed 1. Faithful detection DYNING effect as well. in that stage to maintain the grid's 2. Undistorted amplification In one -tube sets, the quality may be potential at a negative value. Usually, 3. Clear reproduction ruined in the same way, merely by turn- though, the first stage gives a fine Thus we must start with a com- ing the tickler coil a little too close to account of itself. paratively weak impulse, in itself true the oscillation point. In this case, But how about the second step? to the original, make it stronger without it's a question of operation, however. Place the headphones there and turn accentuating any part of it over and If the grid condenser is not perfectly down the volume a little so that the above the rest, and then employ a re- insulated, interfering noises may start phones aren't overloaded. Now it will producing device that doesn't render in it. The grid leak, even more often, probably be found that the lower notes our earlier efforts fruitless. is responsible for hissing and sizzling don't come through so well and that If we attack the problem of undis- sounds, so that it is always wise to test when the volume is boosted a little the torted entertainment with a clear recog- three or four of them, as well as two or crashes on the piano are blurred and nition of the various portions of the three grid condensers to get a good corn- there is a certain fuzziness about it. radio set wherein the faults are likely to bination. A weak station should be Replacing the loud speaker, we shall be situated, we are in a better iposition listened to during this process and the find very much the same thing. With to rectify them. Let's try it in this way. combination yielding the quietest opera- full volume, the loud speaker does NOT The Detector tion chosen. reproduce as clearly as did the phones, Outside of these two sources of trouble, although it will do so if it is connected USUALLY, the reproduction by the and assuming a good tube and batteries, to the first stage (the volume is less, kJ detector is perfect. Headphones the headphones should respond with good however). What is wrong? are plugged into the detector jack by clear music, in which the soprano's 1. The last tube is overloaded and way of verification. However, trouble voice is sweet and pure and in which the hasn't sufficient undistorted variation is sometimes met because of low thud of the drums and the bass of plate current to operate a speaker. 1. Over -sharp tuning. chords of the piano come through with 2. The audio amplifier omits the low 2. Bad grid leak and grid condenser. equal effectiveness. notes. Over -sharpness of tuning can seldom Audio Amplification be found with multi -tube sets having Resistance -Coupling three tuned circuits, nor indeed with PASSING now to the next department The latter of these two faults found single tube sets unless regeneration is too of our research, we tackle the audio with the transformer -coupled amplifier prominent. In tuned R. F. amplifiers amplifier. The loud speaker is left dis- may be corrected easily by the use of an that are on the verge of oscillation, due connected, but otherwise the amplifier audio amplifier capable of amplifying to inter -stage feed -back or to the use of is turned on, ready to work. The head- all moderate frequencies to the same primary windings that are too large, phones are connected across the pri- extent. The audio transformer is in- the sharpness of tuning is extremely mary winding of the first audio trans- herently a tuning device. We know that pronounced. The "side- bands" or slight- former. Do the drums and piano chords the wavelength is equal to the velocity ly different frequencies which convey still stand out? If so, that stage is of the radio wave divided by its fre- the overtones of music or speech are operating satisfactorily and the trans- quency. Thus, WJZ operates on about 12 RADIO AGE for October, 1925 The Magazine of ¡he Hour

a transformer coupled outfit. The coup- ling resistances should be of the order of 100,000 ohms (.1 megohm) and the grid leaks of sufficiently low resistance to allow a suitable negative bias of about 3 volts on the grids without causing too much loss of volume. A grid leak resistance of about 2 megohms for the first stage of resistance coupling, and 1 megohm for the second and third stages each. A "C" battery is very Power ßh..at.7 re4ahws helpful in reducing the "B" battery cur- ira2oap. rent without causing any loss in volume. Care must be taken with such an ampli- fier to use a lower plate voltage for the tube in which the loud speaker isconnec- ted. 90 volts is a sufficient potential for the last stage on this account. See Fig. 1. The quality of amplification may be tested with headphones. First the phones are connected across the GRID Fig. 2 -To prevent overlooding of the lost oudio tube, o heovy power tube moy be em- LEAK of the first amplifier. The ployed, or be as an alternotive neorly os good, two tubes moy operoted in parallel. volume, of course, is very low, but the quality may be noted. The phones are 659,000 cycles, or 455 meters. When resistance and functions on the voltage not connected across the coupling re- we come to the voice frequencies of 100 drop principle. The fact that a resist- sistance, for the tube plate voltage to perhaps 5,000 cycles, the wavelength ance- coupled amplifier operates well at would then rise greatly and the detector is very much longer. Suppose the musi- a very wide range of frequencies is proven probably go into oscillation. To observe cal note has a frequency of 1000 cycles. by its use in the super- heterodyne re- the quality on the first stage of the Its wavelength then is 300,000 meters! ceiver as the long -wave amplifier. In resistance amplifier, the phone cords To amplify at such enormous wave- such a case it is amplifying radio fre- are bridged across the SECOND grid lengths audio transformers have many quency currents of perhaps 10,000 leak. Thus the nature of the input to thousand turns of wire. Small wire is cycles. Vet the self-same amplifier will each successive stage may be listened to used for compactness and an iron core amplify at audio frequency when such and criticized for tonal characteristics. to still further lower the range and to energy is fed into it! In general, these will be above reproach broaden the tuning. Still, the trans- The mechanical and electrical draw- up to and including the grid leak in the last former is a tuned device and just like a backs to the resistance -coupled amplifier stage. The loud speaker may still distort, radio frequency transformer except that lie in the necessity for using 135 to 150 however, even though you may hear the it has more turns of wire and an iron volts of "B" battery and the need for lower notes and the higher notes coming instead of an air core. At best, then, it one more tube than required for the through with much better naturalness than cannot amplify all frequencies equally. transformer amplifier. However, the with a transformer- coupled amplifier. It has a "peak" on either side of which individual plate current is much less the amplification falls off. than with a transformer coupled am- Overloaded Tube The sort of audio amplifier that plifier, so that even with the extra tube ENCE trouble No. 1 of the trans - handles all audio frequencies impartially and extra "B" battery, the total expense H former -coupled amplifier is still doesn't depend on tuning. It uses a per year of operation is less than with met in the resistance amplifier -that á eqb 1jr u ti ej 0 o° e°j 1 ,° ite ee9' ,teg c(° ey.. e9 J ,XO '° LS a fr °o° ,(0 °° Yo / Ç o° ro 1 O ,1y ,1 I (tp

LS 0 SE 1 Y

e .s- t 1 t A A B 67-9C 13S-/ro

Fig. I -Circuit _for o three -stoge resistonce -coupled oudio omplifier together with the detector connections, showing how three different plate voltoges ore required. RADIO AGE for October, 1925 The Magazine of the flour 13 of an overloaded tube. A single 201A of grid bias has slight effect in the case period" of vibration, at and near which or 301A tube does NOT have sufficient of resistance -coupled tubes insofar as it may be most easily set into vibration. variation in plate current to actuate a quality is concerned, so long as there is Hence, although the current through the large loud speaker properly. Of course, sufficient leakage from the grid to pre- windings of the unit may pulse with almost all sets are built that way, but vent the tube from blocking with piled - frequencies of a very wide range, the it is true, nevertheless, that the second up negative electric charges. The use diaphragm or reproducing system is audio tube is receiving variations in of 3 to 4 volts negative is helpful in more readily set into motion by fre- grid input altogether too great for it to that it reduces the plate current some- quencies near its natural. handle. The grid voltage changes NO what, thereby saving the "B" battery. Assuming, therefore, that we cannot LONGER control the plate current Grid bias adjustment for the last am- hear both high and low notes with any with perfection. plifier tube or tubes is very critical, single loud speaker -what is the natural Therefore, the obvious solution to however, and an injudicious biasing recourse in order that we SHALL hear this part of the problem lies in the use may result in a plate current twice both these frequency ranges? Why - of a heavier tube or in using two or normal without much change in quality. to use TWO loud speakers! This may three "A" tubes in parallel to gain the The "B" battery won't last very long seem like a radical suggestion and yet desired effect. The improvement in under such treatment. anyone willing to try such a combination tone quality found in this way is aston- will be at once convinced of its great ishing. The loud speaker talks up with About the Speakers value. Take an ordinary horn type crispness. There's no "draggy" effect THE use of headphones at various of loud speaker, with a diaphragm vary- as the tube tries to recover from one points in the resistance amplifier ing from two to five inches in diameter shock just as another one comes along. will show that amplification of all stages and connect in parallel with it a cone See Fig. 2 for both ways. The heavy is going on undistortedly. And with type of speaker or some other type of tube is to be preferred, in that the the last stage properly adjusted and speaker having a very large vibrating parallel operation of tubes is not uni- supplied with a heavy tube or paralleled system. Arrange switches so that either versally attended with success. A way tubes, the output is practically undis- may be heard separately, or both to- out of this difficulty is outlined below. torted and contains voice and music gether. It might appear advisable to A suitable power tube for such work frequencies of an extremely wide range, employ one speaker for high notes and is the new 202A tube, ordinarily em- just as put into the transmitting micro- the other for low notes, but such does ployed for transmission or speech am- phone. To take full advantage of this clear not prove to be the case. Every fre- plification, or the Western Electric output, the reproducer should be capable quency is accompanied by "overtones," 216A tube as used for power amplifica- of reacting to ALL of these frequencies. which are other vibrations that are tion. The latter may be easily adapted Frankly, however, this cannot be multiples of that frequency. Thus, if to the common amplifier circuit since done. There is NO ONE loud speaker, it were no' for the overtones, we should it calls for no other changes than the so far developed, which does not favor have a ha. ..I time of it to distinguish use of a 1 ampere filament rheostat and certain frequencies, when pushed to one woman's voice from another 's or a boost in the plate voltage to about strong volume. Usually, certain fre- to detect the difference in tone quality 150. It is easy to get this extra plate quencies are favored even on weak between a flute and a fife, or between a VI iltage, inasmuch as it is needed for the volume. This is due in the main to the trombone and a cello. re sistance- coupled amplifier anyway. size of the diaphragm, whether it be of With a heavier tube in the last stage metal such as a disc, or a cone of parch- Adding the Overtones ai id with paralleled "A" tubes of the ment or paper. A small diaphragm By the addition of these overtones 01 dinary type, the grid leak resistance favors the high-p itched notes of the the differentiating qualities stand out m ust be reduced somewhat. The re- soprano, women's voices, the flute, plainly. Using two loud speakers in q wired leak may be y megohm to .1 violin and the like. On the other hand, this manner, the faint overtones giving IT egohm -a lower resistance than .1 the cone speaker, with its large expanse richness to the tenor's voice improve the m :ver being necessary. If a millimeter of vibrating material, delivers the low color and depth of reproduction in an ia at hand, the grid biases and plate frequencies with greater vigor, like the almost indescribable fashion, yet are ltages can be adjusted to a nicety, bass singer, the violin, the chords on the evident to even an inexperienced ear. Sc that the plate current is not too high harp and chords on the piano and so on. It is very easy to point out the improve- fc r the tube in use nor so low that it A loud speaker has yet to be developed ment when the two speakers are con- fa ils to amplify weak impulses as well which does not depend upon some vi- nected with switches for quick changes a strong ones. In general, the grid brating system by which the sound with either or both in circuit. Using the b as should be made more and more waves are set in motion. And any such horn speaker, with a jazz band coming gative until both quality and volume vibrating system, depending upon its in, the melody stands out most promi- d crease noticeably. The adjustment magnitude, has more or less of a "natural (Turn to page 67) s^

C

. . . . .

MIMI J i I

( P.n

S Ffcr3 Ft G

F ig. 3- Using two loud speakers to cover the entire musical range, one for higher frequencies and the other for low; the double tube connection allows a separate tube for each speaker. Fig. 5- Details of the mandolin low-note loud speaker. 14 RADIO AGE for October, 1025 The Magazine of the Hour Where Does the POWER for Your RADIO Lome From?

Correcting the Erroneous Impression that All the Energy Comes from the Transmitter; Power Creating Sounds in Home Due to `B' Voltage

WHEN your loud speaker is re the first overtone becomes the most producing a good program of By EDGAR H. FELIX prominent; the second is of the same dance music with sufficient vol- order of energy as the first; the third is ume for half a dozen couples, an appre- larger than the second. On the other ciable amount of energy is required to second. Each individual note emitted hand, the middle registers of the flute produce such loud signals. Where does by musical instruments consists of a played powerfully are again almost pure that energy come from? How much of fundamental frequency, determining the tones. it does the transmitter of the distant pitch of the sound, and a number of The oboe has twelve or more harmonics, station contribute? harmonics, serving to give each instru- the fourth and fifth predominating, with Actually, a receiving set with 90 volts ment its individual character. You can 30 and 36% respectively of the total of "B" battery may pass as much as 6 distinguish whether it is the middle C loudness. milli- amperes through the plate circuit or any other pitch by the frequency of Each instrument, therefore, has its of the last tube. This amounts to approx- the fundamental. peculiar characteristics, varying through imately half a watt. Yet, the power The harmonics, consisting of multiples the various registers. All of these are received from the broadcasting station of the fundamental pitch set up by each combined and utilized by the composer is frequently less than one -millionth instrument, enable you to distinguish to secure pleasing and harmonious of a watt! The power actually creating between the piano, violin, saxaphone or effects. sound in your home, comes front the any other instrument. For instance, if When you consider the fact that faithful, hard -working "B" battery. the C an octave below the middle C sometimes as many as eighty instru- Radio transmission and reception re- is played on the piano, 129 pulsations ments are contributing to an orchestral quire many processes and conversions, per second are set up. This is the fun- program involving at any particular all of which can be successively performed damental frequency, determining the instant half a dozen different funda- without the introduction of any ex- pitch as that of the C below middle C. mentals and five times that number of traneous noises or distortion. Also, there are harmonics of 259, 388, harmonics, the composition of all these But, unless you understand the many 517, 647, 796 and so on, consisting of steps which occur from the time the multiples of the fundamental. The air wave impulses is indeed highly program is rendered in the studio until violin, sounding the same pitch, has the complex. This is the first step in radio it is finally re- created in your home, you same fundamental and the same har- telephone transmission -the creation of cannot fully appreciate how anything monics. It is the distribution of the sound waves consisting of air wave approaching that fidelity of reproduction energy on these harmonics which enables impulses of many different fundamental is attainable. Numerous explanations you to distinguish whether there is a frequencies and a wealth of harmonics. of the transmitting and reception process violin, piano, flute, oboe or clarinet The first conversion process is the use have been written, using freely such terms being played. of these complex air waves in controlling as "sound waves," "radio frequency," an electric current. The microphone Fork "electro- magnetic waves" and "audio - Tuning Purest effects this step. It consists of a dia- frequency." Usually these terms con- ASTUDY of the nature of musical phragm which vibrates when sound waves vey only a vague meaning to the non- sounds is indeed an interesting one. strike it, just as your own ear drums do. technical reader. But it is not difficult The tuning fork gives the purest tone Instead of affecting nerves which register to visualize just what takes place from because all of its energy is radiated in in the brain, the microphone's ear drum the time the program is rendered at the the fundamental. The flute comes next compresses carbon granules packed loose- studio until it is finally reproduced in in purity of tone. When a low tone is ly behind it. When highly compressed your home. played softly on this instrument, 95% by a powerful sound wave, the resistance We begin first with sound waves, the of the energy is concentrated in the of the carbon granules falls markedly. result of the artist's performance in the fundamental, with just a trace of energy Less powerful sound waves do not reduce studio. A musical program is a complex in the harmonics: When lower registers the resistance as much. The microphone combination of different sound waves are played powerfully, or overblown, is placed in series with a steady source of having various frequencies, between the fundamental is weak; being just potential as the resistance of the micro - sixteen and five thousand impulses per loud enough to characterize the pitch; (Turn to page 50) RADIO AGE for October, 1925 The Magazine of the flour 15

A back view of the amplifier de- scribed by Mr. Pfaff, showing sockets and oth- er instruments neatly arranged.

For DISTORT1ONLESS Reception

A NEW AUDIO FREQUENCY AMPLIFIER- RESISTANCE COUPLED

AVERY good parallel may be By in favor of one range of frequencies at drawn between the progress of Ernest R. Pfaff the expense of another range, as in a radio broadcasting receivers with transformer coupled amplifier. Trans- the public, and the development of the step -up ratios used. This resulted in formers cannot be built to give abso- phonograph, with respect to the stand- the present day transformers which lutely uniform amplification, due to ard of quality of reproduced signals amplify with very good uniformity all the resonance characteristics of the that was demanded several years ago, frequencies between two hundred and windings that must be used. and the standard that today will satisfy six thousand cycles. But even in the In actual practice two stages of the discriminating enthusiast. When best of audio transformers, there is a transformer audio amplification are about radio first came into popularity, the very decided drop in amplification below all that can be used, due to the build- influence of the telegraphing amateur two hundred cycles, which becomes ing up of noise in the system and the was most strongly in evidence in audio greater as the frequency decreases. fact that such an amplifier in conjunction amplifiers, for this amateur desired not At sixty cycles, the amplification of the with a good receiver will give plenty of quality of reproduction, but high ampli- average audio transformer is practically volume for loud- speaker operation. How- fication per stage. In fact, the ideal negligible, as compared to its amplifica- ever, three stages of resistance coupled audio amplifier for telegraph reception tion at frequencies above two or three amplification will be required to give would be one that would accentuate to hundred cycles. the same or slightly greater volume, the greatest possible extent only the since the gain per stage in such an particular frequencies used for modulat- The Organ's Faults amplifier is lower than in a transformer ing the transmitting wave. NYONE who has listened to an coupled amplifier. This will be appre- Because of these requirements, prac- organ as received on the average ciated when it is realized that one trans- tically nothing but transformer coupled radio set is only too well aware of the former and one tube will give a voltage audio amplifiers were in use, the trans- absence of the lower frequency notes. gain of about 18. When the second formers themselves generally having a When listening to the organ, say in a stage is added, using exactly the same step -up ratio of six to one or ten to one. church, we are all familiar with the deep equipment, this figure falls off, due to Their design was such that they amplified vibrations evident on the low notes; certain inherent characteristics of such best at some hump in their curve; in yet how many radio enthusiasts have systems. Therefore, we can allow a the case of one, built by a nationally ever felt the walls of their homes vibrate gain of 18 in the first stage and about known manufacturer, the maximum when listening to a broadcast organ 13 in the second stage, or an over -all amplification secured at twelve hundred selection? But where a resistance coupled gain for the system of 18x13, or 234. cycles was several times that obtained audio amplifier is used, the fidelity of This means a signal is 234 times stronger at 100 cycles. Then, as broadcasting reproduction is so great as to cause when it comes out of such an amplifier came in, requirements changed, and the doubt in the mind of even the best than it was when it went in. These desirable amplifier for this class of trained musician as to whether the figures are low, for great amplification reception was one that would amplify selection heard is actually being played cannot be obtained from a transformer uniformly all frequencies from sixty in his presence, or is being broadcast. amplifier designed for good quality. to six thousand cycles. Due to the inherent characteristics In the case of a three -stage resistance Transformer design was improved, of resistances when used for coupling amplifier the gain per stage will be about with a general tendency among manu- purposes in an audio amplifier, sub the same for each stage, since the drop facturers and designers to reduce the stantially no discrimination takes place encountered In the previous case does 16 RADIO AGE for October, 1925 The Magazine of the Hour using 135 volts on the amplifier, the tube resistance may be considered as about 20,000 ohms, which give a total plate circuit resistance of 120,000 ohms, across which is applied 135 volts. For practical purposes, it may be considered that this voltage divides so that the actual plate voltage of the first two tubes is about 34, so that no "C" battery will be required. If a higher resistance were used, a higher plate voltage would be necessary, but if a lower resistance were used, the amplification would fall off badly. Further, the size of these coupling resistances is about five times the tube resistance, which insures prac- tically uniform amplification at all fre- quencies to be handled. Actually, Figure 3. A bottom view of the amplifier, giving a good idea of hou, resistances the variation in amplification between and condensers are mounted, 60 and 6,000 cycles is only a few per cent. The grid leaks are of such a size that they will prevent blocking of the system, not apply to any appreciable extent, pact arrangement, it may be placed and maintain the grid potential of the Therefore, we can allow a gain of about in less than the space required for the various tubes at a satisfactory operating 6.5 per stage or about 81% of the ampli- standard amplifier in almost any receiver value. One -half megohm, or 500,000 fication factor of an average tube. design. ohms, is used on the first stage, with This in three stages gives a total ampli- The constants of this amplifier are one -quarter megohm, or 250,000 ohms, fication of 275, or slightly more than so proportioned that the maximum on the second and third stages. that obtained with two transformer amplification will result with a minimum Because of the high resistance used stages. of current consumption. The .0073 for coupling the output of the receiver Expense coupling condensers have a compara- (or detector) to the amplifier, the plate tively low reactance to the frequencies voltage of the detector should be about 'PROM the standpoint of expcnse, to be handled, and are a far more prac- 90 volts, instead of the customary 45. the resistance system can be built tical size to work with than those of If the amplifier connects to a receiver as cheaply, or more cheaply, than the a larger capacity. Theoretically, thesc using audio amplification, the plate transformer system, due to the lower condensers should be on the order of one voltage of the last tube in the receiver cost of the component parts. An addi- to five microfarads, but practically, should be run up to 90 or 135 volts. tional tube will be required, which will .0075 is entirely large enough. The The resistance in the plate circuit about even up the price of the two use of one of these condensers connected of the last tube is only that of the loud outfits. from plate to filament of the last stage - speaker -generally 2,000 ohms -so that While 135 volts will be required for a point commonly overlooked- prevents practically all of the plate voltage used the resistance system, the B battery poor quality often experienced with is applied to this last tube. This being current consumption will be only about resistance amplifiers. the case, a C battery should theoretically nine millamperes, as against ten to The coupling resistances are of 1 -10 be used in series with the last tube's eleven for the transformer system. megohms or 100.000 ohms. 11'hen grid leak, of about 3 to 6 volts. Actually Therefore, the B battery expense for this does not improve reproduction, both systems being about equal, with and so it is not shown in the amplifier the initial battery expense higher for the circuit. It will reduce the B battery resistance amplifier, and the upkeep consumption somewhat, and may be cost of the transformer amplifier nearly incorporated if desired. balancing this, there is no reason why The current consumption of the first the average fan should not enjoy the two tubes is on the order of 1.13 milli- wonderful quality to be obtained with amperes per tube, while for the last the resistance tube it is about system. 12 to 14 mils. The amplifier This makes a total unit described of 14K to 16K herewith is the mils, for the three result of consider- stages, which may able experiment. be cut by four and if it may be or five mils. by judged on its per- using the C bat- formance, its con- tery referred to, struction will be ON THE LAST very decidedly STAGE ONLY. warranted by the Figure 3 is a true music lover. bottom view of It is so designed the unit, showing that the unit itself placement of the may be mounted six resistances and upon a standard four condensers, panel, or it may O O O ¡ O ¡ these being at- be incorporated tached to a bake - just as it is in O lite strip carrying any standard re- the five binding ceiver circuit in posts, which is in place of the con- turn fastened to ventional trans- figure 2. Wiring diagram for distortionless audio amplifier. As all parts have been three panel - former amplifier. illustrated pictorially, rather than in symbols, this diagram is very easy to follow, even by mounting sockets. Due to its coot the inexperienced set builder. (Turn to page 60) RADIO AGE for October, 1925 The Magazine of the Hour 17 An IMPROVED Slide Wire Bridge

THE slide wire bridge described in Ieceiv)ug bet has been explained, yet the February issue of RADIO AGE By H. FRANK HOPKINS very few set builders know how to balance has proven itself so popular and of and match the parts they are about to such an asset to set builders and experi- build or use. With the aid of this in- menters that, in answer to numerous strument it is within easy reach of the requests, the writer has completed an A New Design for most inexperienced novice who has only improved model of this instrument, a limited knowledge of the radio or wherein the construction has been so Measuring Capacity electrical science as well as to the more simplified as to bring it within reach of experienced fan with his advanced ex- the most inexperienced novice and yèt perience and array of equipment. All retain the accuracy and ease of operation him to match and balance his parts with that is necessary for the successful opera- so necessary in an instrument of this a close degree of accuracy, heretofore tion of the slide wire bridge is a knowl- kind. attainable by only the more advanced edge of simple arithmetic and the use This instrument seems to have filled fan with his home laboratory and his of a little good judgment. a long felt want for the layman, making knowledge of radio and electrical phe- it possible for him to measure the capacity nomena. RILE it is true that there are other of condensers, the impedance of coils, Time after time, the importance of instruments that will show a little transformers and such, and to enable matched parts and a well balanced more accuracy on certain operations

1:) ,M1f ),=1f1EfZ1anslcmclr=)7fT

Fi6URF 2 I /'/N6 D /RCRNM OF COMPLETE 5CHEMATIC DIAGRAM of /N$TRUMEN T. /SEE N /RING 7.98[F) THE BRInGE CIRCUIT. CIRCUIT D/AÇRAMJ FOR THE IMPROVED SL /DE WIRE B.e /DGE. A9/ ,er/ 18 RADIO AGE for October, 1925 The Magazine of the Hour such as peaking transformers with a be drilled in the panel, 3 1 -2' down lroul of soft iron wire, making a spool. wave meter, measuring capacity by use the top and 2 1 -2" in from the side. This Shellac or glue may be used to fasten of a modified form of Wheatstone Bridge, is for the dial shaft of the potentiometer all parts, and it would be well to tie all called a Capacity Bridge, and such, it and is large so as to prevent the shaft of the windings with shellac or glue when also becomes more difficult because more from binding against the panel. The each coil is completed. intricate mathematical formulae and mounting holes for the potentiometer The primary coil will be wound in additional expensive equipment are re- will then be marked and drilled. These even layers directly over the iron core quired. The slide wire bridge covers holes will be countersunk from the top on the wax paper wrappings. Two hun- more ground than any of the other in- of the panel to take a number six, flat- dred turns of No. 20 B and S gauge, struments and it also keeps the mathe- head machine screw. double cotton covered, copper magnet matics down to plain multiplication, Four holes will be drilled and counter- wire will be required. Both ends of this division and subtraction, while it shows sunk to take number six, oval head wood winding will be brought out through results as accurate as necessary for this screws. These are for mounting the holes in one of the end pieces of the spool type of work. It is also the only simple, panel to the case or box for the instru- and the entire coil covered with about accurate method of determining im- ment, and care should be taken to see six turns of wax paper, thus completing pedance at various frequencies. that they are not too close to the outer the primary coil. All of the parts used in building this edge or the screw may split the box. The secondary coil will be wound di- instrument have been given a desig- When the panel is completely drilled, rectly over the primary coil and on top nating letter or number; each terminal the potentiometer (P) will be mounted of the wax paper wrappings. Be careful is numbered both in the circuit diagrams and the dial attached. The hole for to wind the wire for this coil in the same and the wiring table. This same desig- mounting the dial marker will then be direction as was done for the primary nation is applied throughout the article located and drilled to fit. The scale coil. Six hundred turns of No. 30 B and in the formulae that follow so as to for the dial will complete the top panel and S gauge, double cotton covered, readily recognize each part and its place layout. However, we will lay this part copper magnet wire will be necessary, in the circuit. The parts used in building of the bridge aside for the present and bringing each end of the winding out the instrument are all standard equip- start on the box equipment. through holes in the end piece opposite ment and may be purchased from any Mounting the Equipment to the primary leads. reliable dealer. The parts should not It would be well to splice a piece of cost the fan over ten dollars. They are r p WO brass details, shown in figure stranded wire to tife secondary coil as follows: 1 three, will be made and fastened to ends, taking two or three turns and One -400 Ohm Potentiometer (P) the bottom of the box as shown in figure bringing out through the end piece in One -High Frequency Buzzer. (900 four. These details will be spaced to place of the No. 30 solid wire, as this to 1000 cycles) (C) fit the type of flash light battery to be is rather delicate and hard to handle. One -Small induction coil or open used. Number six round head wood Ten turns of wax paper will then be core transformer. Construction of screws will be uscd to mount all of the wound around the coil and made fast, the proper type described in this equipment except the buzzer; this will completing the induction coil, (I). This article (I) have the screws usually furnished. coil will then have four leads or terminals. One-3 to 4 1 -2 volt, Flash light An induction coil (I) or open tort The inside lead of the primary coil will battery (E) transformer, having a low impedance be (I1), the outside primary lead (I2), One -Metal plate dial (S) value and a ratio of transformation of the inside secondary lead will be (I3) One -Dial Marker (SM) about three to one, may be purchased and the outside secondary lead will be One -Battery switch (SW) for about one dollar, or it may be made (14). The coil will then be mounted in Six- Binding posts (X, X1, Y, Yl, at an even smaller expense, as follows: the box or case as shown in figure four. R, RI) A bundle of soft iron wire, No. 20 B The Buzzer One -Set of brass clips for mount- and S gauge, having a total diameter of ing flash light battery (E) about five- eighths of an inch and an AHIGH frequency buzzer, (900 to One -5'x7 "xl -8' Composition pan- overall length of four inches will be 1000 cycles) may be secured from el securely tied and wrapped with about any reliable dealer for about two dollars. One- 5'x7'x5' Case or wood box ten turns of good wax paper. Two pieces It should be enclosed under a metal X- Miscellaneous screws, wire, sol- of wood, one quarter of an inch thick cover. A buzzer of this type is required der, etc. and one and one half inches square, will to set up a current whose frequency is The first step in building the instru- have a hole drilled in the center large somewhere near the average frequency ment will be to lay out and drill the panel enough to fit snugly over one end of the of voice currents to better balance and for mounting the potentiometer (P). iron core. One of these pieces will be measure equipment subject to voice A hole one half inch in diameter should made fast to each end of the bundle (Turn to page 53)

DR /LL FOR O G =g-6 WOOD SCREW

ïJET.9/L H (BRHS!)

DR/L L FOR *G o HOOD SCREW.

O 7JETH/L B (BP.' 3"-/) .4CTU.9L S/IE !L'JW 176'U/2E 3. ,S,t rrE.Pr ¡E) F//',LAPE S. PA.PT/AL D/FL JCHLE. XXI .9S5EMBL Y & DET.9/L 5 UL L J/ZE ki,X TOR THE /M,:POI/ED JL/DE /76-CAPE 4. W/,PE B.P/DGE. /9SSEMBL Y OF BR /OFE P.9.P7S. IN BOX. RADIO AGE for Oiii,her, 1435 The Magazine of the Hour 14 Electricity The Life of the World

11 The Wise í'' Old Man of the Night Sheds Some'',`jt_ "; Light on Radio's You were wonder. in what keeps the Miracles sun, moon and stars 0 in their relative positions, and what effect they have on this world of ours," said the Old Man. "Well, I will tell you."

A STORY THAT DELVES INTO RADIO'S FUTURE -BY FRANK D. PEARNE

BILLIE McINTYRE leaned back night, and what influence did they the little which 1 did accomplish, science from the key and stretched out exert upon this little world of ours? lias rewarded nee by mentioning my his arms with a deep yawn. This work and experimenting and by placing had been a particularly interesting night A Stranger Enters my image in the hall of fame." for Billie, as he had reached more of his THESE and many other questions Suddenly the light of recognition came ham friends in the last three hours than flitted across his mind as he became to Billie. That face he had seen in some ever before in a single night. Being deeply absorbed in the wonderful spec- of his old books. "You are -?" he somewhat of a dreamer, his mind began tacle before him. exclaimed, but the little man held up to wander from the dots and dashes of Suddenly he became conscious of the his hand and stopped him. the last few hours to the more mysterious fact that he was not alone, and even "Never mind who, -my purpose in things of life. He marvelled at the won- before he could turn around he heard coming here is to get you but of this rut ders of nature, for his West Virginia a deep voice behind him drawling out -to give you a new train of thought friend had just clicked off the informa- the question: and to try and make you do a little tion that a terrific thunderstorm was "Well, young man, have you figured thinking for yourself." about to break and gazing out through it all out ?" Billie made a gesture and opened his the window he looked upon as clear and Turning quickly, he beheld a little mouth to speak, but the little old man beautiful a sky as he had ever seen. gray haired old man looking at him stopped him. It was hard to imagine a thunder from across the room. Strange to say, "Please do not interrupt me, for I storm from a sky like that. What Billie was not startled. It all seemed have much to say to you in the short time difference a few hundred miles could perfectly natural for some reason or I can be with you, and I know what you make; what was this great power that other, and something seemed to assure are going to say. Electricity is the life could turn these heavens into a hunt - him that even at such a late hour what- of the world. You were wondering dering whirlpool of wind, rain and ever might be the mission of this queer about the sun, moon and stars, and what lightning? looking individual, it meant no harm keeps them in their relative positions, Much of his life had been spent in to him. How he had found his way into and what effect they have upon this dreaming, studying and experimenting. the little laboratory through a carefully world of ours. He watched the magazines and read the locked door did not seem to bother him. "Has it ever occurred to you that best books, and the many theories of Rising slowly from his chair, Billie this planet, like the others, is whirling radio transmission and reception which walked toward his visitor. around at tremendous speed, and that he absorbed in the process had made "I -I don't seem to remember you, this condition might cause It to become him wonder what it was all about. sir, but there is something very familiar highly charged with electricity? Have To Billie, there were many things yet about your face," he said. you ever tried to experiment with a to be explained to his satisfaction. Light- The little old man chuckled, "No, number of very light bodies which have ing up the old pipe, he walked across son, there is nothing strange about your all been charged with electricity, and the room to the window and sat down not remembering me, for I passed on noticed how they repel one another, gazing out at the sky above him. from this earth many years before you keeping them separated at a distance, What were all these tiny stars blinking were born. I, too, struggled with these depending upon the strength of the at him? Why were they always there problems of yours -struggled hard and charge which they hold, and also that in the same place and order night after patiently -when I was young, and for when relieved of their charge the re- 20 RADIO AGE for October, 1925 The Magazine of ¡he Hour pulsion ceases, or if some of them are "You need no evidence to prove that are caused by the sudden neutralizing given a positive charge and some a light waves exist and the heat waves of some of these life -giving electrical negative charge they rush together? will also exert themselves upon the waves from the sun, or their effect upon What then is more natural than to senses, but what of the electrical waves? the body. It matters little, which side suppose that these planets with their Knowing that these waves must exist, of the earth the sun happens to be on, enormous electrical charges -in fact, you have often wondered how you could as it is all under the influence of these charges of electricity which are so great make use of them. Science will probably waves, but your own scientists say that as to be far beyond the comprehension discover in time, that these very elusive when the sun is on the opposite side of of man-act in the same manner and waves are the most important of all. the earth, human life is at its lowest float around in space at a respectful They may find that these electrical ebb, which may prove that these waves distance from each other? waves are making it possible for life to do not penetrate the earth as readily "Do you suppose that this little exist in this great charge of electricity as they will affect it from the outside. mechanism which you call a generator which surrounds you. In other words, their strength is some- really produces anything? You use it "I notice that you have what you call what reduced by passing through the every night to converse with your friends; a high frequency coil over there on your earth. other so- called generators apparently work bench. You have always been "Why do you always choose the night supply the energy to give light, heat under the impression that this coil hours for transmitting your radio signals? and power, but good, fair reasoning would produce a high frequency dis- Because you find that signals will go should convince you that man creates charge, and as usual you are wrong. much farther at this time, because they nothing. We are, in fact, prisoners on You employ a condenser in this circuit are not so much affected by the sun's this little planet and have no power to -the fastest operating piece of apparatus electrical waves when it is on the other reach out from it and obtain anything known to man, and by utilizing some of side. which is not already here. The only the earth's charge, you cause this con- How the Sun Affects Us thing which you can do is to alter con- denser to charge and discharge at enor- HAVE you ever witnessed the effect ditions in such a way that these changes mous speed. Did you ever look at this of the northern lights at certain may be beneficial to mankind. times of the year? Where these demon- "Is it not more reasonable, then, to strations take place, the conditions are suppose that your so- called generators PRISONERS ON EARTH I not the same as they are here. Days merely act in such a way that they make The Wise old Man of Mr. Pearne's and nights are six months long up there use of this great charge by causing a article gives an interesting view- in the north. Sooner or later science difference in its strength between the point of man's relation to the earth find the present day theories he inhabits. may that points covered by the electrical circuits are all wrong in regard to these phe- connected to them? " We are prisoners on this little nomena. It may find that the lack of planet and have no power to reach "Fortunately for you and the rest of out from it and obtain anything the greater power of the sun's electrical the human inhabitants of this earth, man which is not already here," he says. waves has much to do with these dem- has not yet found any means of making "Fortunately for us, man has not onstrations. any appreciable change in this charge. found a means of making any appre- "It is hardly possible that because The small amount of energy which he has ciable change in the earth's actions. the sun is missing from this region for succeeded in moving from point to point The small amount of energy which such long intervals, the earth's charge has had no effect upon the earth's loca- man creates has no material effect is not held in check so faithfully during to othcr planets, but compared to the other planets -but and that this charge shows tion compared should the time come when man this time, should the time come, when the re- does do something of a revolutionary itself in the great bluish glow which quirements cause enough change in this nature in science -look out! The fills the heavens at certain times of the charge to lessen its repelling effect, look earth might change its position year. There are many other proofs out for unusual things to happen. The and chaos would result." - of the existence of electrical waves com- earth might change its position in re- ing from the sun, and do not think that lation to the other planets." it is necessary for you to find a way to Billie listened intently as his strange from a different angle? Did you ever utilize them -they are doing their work visitorr ambled on. Many ideas suggested stop to think that in dealing with such just as surely as the light and heat waves fanciful things as he listened. What high speed of vibration that you were are doing theirs. would happen if the earth changed its coming within the range of the speed of "Remember that millions of waves position? Life is possibly only within electrical waves from the sun? are coming to this earth from the sun, a small range of temperature. Any "I don't suppose that it ever occurred and it is hard indeed to find the dividing slight change in the position of the earth to you that this might be just the earth's line between them. They are all mixed might cause it to become so hot or so charge exerting its power. I might up so far as we can see. A common cold that the inhabitants could not suggest that perhaps the function of magnifying glass will pass light waves exist. Is this great thirst for power these electrical waves from the sun is through it and when properly focused really a menace to humanity? Would merely to neutralize the effect of the upon any combustible material, will so the time ever come when the earth, earth's charge, thus making it possible concentrate the waves to a small pot relieved of its repelling power, would for life to exist and other conditions and produce enough heat to ignite the go crashing into some other planet? which would be entirely different without material, showing that near the dividing "Now," said his friend, "we come to these waves, therefore, when you operate line in light and heat waves, they may the most interesting of all of these your high frequency coil, you produce be both. What other waves may be theories. Without the sun, animal life nothing but a vibration which comes discovered in the future is hard to imagine, could not exist on certain planets which within the wavelength range of the but rest assured we know very little come within its range, for it sends forth electrical waves, counter -acting the neu- about them at the present time." waves of all lengths, many of which are tralizing effect of these waves upon the Billie listened closely to all the little beyond the senses of man to recognize. earth's charge, and this charge then han had to say. He seemed to be carried The principal waves of interest to you begins to assert itself in the form of a on into a new world. He began to feel are the shorter ones, which produce the bluish glow about the conductors which a cold perspiration coming over him, effect of light and heat, varying over a are connected to it and causing a tre- and looking over at the high frequency great range. Light waves of various mendous discharge across the terminals coil which his friend had so carefully length produce different colors and all of the coil when they are brought close explained to him, he observed that it combined make up the pure, white light together. was beginning to show the bluish glow which makes it possible for you to see. "Is this not a case of setting two of of which the old man had spoken. Sud- As the waves become longer, they affect nature's forces against each other? If denly there was a flash across the ter- the senses by producing heat, and when you will give this theory some thought, minals and a deafening report broke they become still longer, they become you may find that certain electrical in upon the conversation. electrical waves. shocks which are fatal to animal life, (Turn to page 40) RADIO AGE Jur a tuber, 1925 The Magazine of the Hour 21 An Organized War Against Radio Fading Bureau of Standards Engaged in an Unusual Attempt to Solve Radio's Troublesome Enigma

By S. R. WINTERS

THE signals are being heard %%ith Above is a view of the apparatus assembled by T Parkinson of the Radio Labora- such surprising clarity and in- tory of the Bureau of Standards in Washington, D. C., for conducting tests relative to tensity that you marvel at thn the 'fading" of radio signals, achievements of radio. Then, wit an abruptness that is disconcerting, the signals weaken rapidly until they may these measurements are so complicated ing detector to produce the beat note become completely inaudible. Mean- that the participants in the tests are and have similarly measured the audio - while, the voice of the speaker or the necessarily limited to college and com- frequency output. One unfortunate musical strains If the orchestra are se em- mercial laboratories. However, thou- feature of the latter arrangement is that ingly chopped off and you suffer the sands of radio fans and amateurs who relatively distant generating ('oscillat- exasperating experience of having the are not properly equipped for under- ing') receivers may also cause an audio - continuity of the radio program broken. taking these experiments will be in- frequency beat note which is very This strange phenomenon in radio trigued by the imposing mechanical and effective in causing galvanometer deflec- reception is described as fading or electrical equipment employed. tions. Such disturbances, though audible swinging of signals. Various theories The apparatus assembled by T. Park- with the super- heterodyne, have much have been advanced in attempts to inson of the Radio Laboratory of the less influence on the galvanometer and explain this enigma but thus far it has Bureau of Standards is illustrated in very often cause no observable change defied a plausible explanation that would the photograph and diagram reproduced whatever. point to the source of the trouble. It is with this article. The pretentious "It is also feasible to use other types more baffling, and at times more annoy- equipment and novel arrangement are of radio -frequency amplifiers, providing ing, than static. Signals from some inviting enough to the experimenter. the recorder galvanometer, with rectifier, stations are thus peculiarly afflicted- It is not conventional in appearance. is so connected as to measure the ampli- notably, KDKA of East Pittsburgh - For instance, a super- heterodyne radio fied radio -frequency current. In no case, and, not unlike atmospheric disturbances, receiving set is shown in the background except that involving a definite audio - fading is more pronounced at night of the picture and, despite customary frequency beat note, should the output than during the day. practice, there is no loop or coil antenna of the audio- frequency amplifiers be The Radio Laboratory of the Bureau available. Purposely, this type of energy measured. Otherwise marked variations of Standards, in recognition of the collector is avoided because in making due to modulation will appear on the extent and undermining influence of this fading measurements directional effects record and make it impossible to dis- radio wave phenomenon, recently in- are undesirable. A loop or coil antenna tinguish fading effects. Also, when the augurated the most comprehensive inves- has pronounced directional character- beat method is employed it will be tigation of its kind ever undertaken. istics. If only a radio receiver with a necessary to keep the beat note at the These observations, under the direction loop antenna is available, an open aerial same pitch if comparisons are to be of T. Parkinson, a government radio may be coupled to the receiving outfit, dependable, as the amplification may engineer, will extend over a period of the secondary coupling coil having an vary markedly with the frequency in many months and have enlisted the co- inductance equivalent to that of the coil audio- frequency transformers." operative efforts of college and com- antenna and is substituted therefor. The specially designed unit for observ- mercial laboratories, distributed over a ing the pranks of fading or swinging wide area of the United States. Quanti- THE type of receiving set most signals is entitled "Type 289 Fading tative and qualitative measurements and generally used by observers," in- Recorder," and is obtainable from the possibly directional observations of fad- dicates Mr. Parkinson, "is the super- reputable manufacturers. This outfit ing will be made. heterodyne, which has apparently proved includes a sensitive galvanometer. Two Unusual experiments require uncom- satisfactory. In one instance a neutro- types of motors are available for driving mon mechanical equipment. This state- dyne was used and a heterodyne oscillator the clock -like mechanism of the recorder ment is especially applicable to the was employed to produce an audio - -an electric or a spring motor drive. apparatus to be used in these fading frequency beat note with the received The former is a 60 -cycle electrically - observations, special equipment being carrier, the beat current being measured driven motor, power being obtained designed for this purpose. The truth is, at the output from the audio stages. by connecting it to a 60 -cycle alternating the method and apparatus for making One or two others have used the oscillat- current lighting circuit. The spring 22 RADIO AGE for October, 1025 The Magazine of the Hour motor, somewhat amplifier or detec- bulky, requires tor tube. Since winding every five TWO CLUTwooC. changes in crystal or six minutes. TUBE- sensitivity, due This type of mot- probably to son - ive force, however, tact variations, has the two -fold sometimes produce advantage of mak- records very simi- ing the observer lar to fading independent for curves, this meth- field work and of od is not altogeth- eliminating any RUOROCR FIG 1 . er dependable. interference that "The method of might emanate AUDIO balancing out the TO normal plate from electrical AMPLIFIER cur- devices. This rent of the detec- recorder carries tor tube by means i with it a kymo- of a small current graph drum to supplied by a sepa- move the record- rate battery and ing tape and a flowing through pen for writing the galvanometer down the observa- in the direction op- tions. This gra- posite to that of phic record is ob- FIG 2 the 'B' battery tained by means current has been of a hand -operated tried and usually lever which follows has proved un- the galvanometer stable. The bal- deflections. ance is difficult to "One or two ob- hold under the servers have made best conditions their own record- and with many ing outfit," notes tubes is impos- Labor- sible." the Radio FIG' 3 atory of the Bu- "A more depend- reau of Standards, able arrangement "and some others than either of have simply used these," indicates a galvanometer Mr. Parkinson in alone and taken describing the readings several method employed times a minute, at the Radio Labo- plotting these oa.wN SCALE ratory of the afterward on co- BUREAU OF STANDARDS IRACEDy/Y) Bureau of ordinate paper. ñr1.1 s 'tr Standards, "is the WASHINGTON, D. C. CNECAED.. DRAWING NO Very good records two -electrode elec- MIRRORED 995 showing the major DIVISION SECTION_. NO. SHEETS._.... 'SHEET NO tron -tube rectifier. variations have One of the secon- been secured in The above chart, prepared by the Bureau of Standards, gives an indication of what dary terminals of a this way. The will be done in the nation -wide drive to enlist radio fans in the wa r against esasperat- radio- or interme- continuous rec- ing radio signals. mediate- frequency ord, on the other transformer is con- hand, is easier for nected to both the observer and shows up the smaller instrument than that already specified. plate and filament of the electron tube fluctuations which may sometimes prove However, the galvanometer employed while the other terminal is connected significant. A number of records made in the fading recorder being described through the recorder galvanometer to during the recent sunset fading tests, has a resistance of 2,000 ohms and a the negative filament. Although no for instance, show a rapid periodic full -scale deflection of 10 micro -amperes. 'B' battery is used, there is a space swing starting about fifteen minutes In all cases, it is recommended that a current which may be balanced out by after the local sunsets at the observing sensitive direct- current galvanometer be turning the galvanometer zero adjust- points and lasting approximately a half employed with a rectifier in such a ment until the instrument, with no in- hour. Such effects may give a helpful manner as to measure variations in coming signals, reads zero. clue and would appear only on the con- the received carrier -wave current. This "The UV -199 type of vacuum-tube tinuous record. In this connection it Shaw recorder, so called, moves the is apparently most satisfactory, the space should also be stated that the fading paper, upon which the observations are current to be balanced out being small is sometimes so rapid that a slow- motion written, at a rate of five- eighths of an and the sensitiveness being fully as clock drum will result in a merging of inch per minute. great as that of a very good crystal de- several fluctuations into one heavy line "A number of arrangements have been tector when used in circuit with the same on the record." experimented with for rectifying the transformers and galvanometers. The radio- frequency current to be measured," UV -201A type of tube is also workable USE of a sensitive galvanometer, suggests Mr. Parkinson, who is con- but the space current is so great that it having a full -scale deflection of 14 ducting these fading observations for becomes necessary to get at the interior micro- amperes, is recommended, although the Bureau of Standards. "The simplest of the galvanometer to turn the zero some observers have succeeded in obtain- of these," he explains, "is the crystal control sufficiently. ing such amplification that currents as detector in series with the galvanometer "It may also be balanced out by a great as 160 micro -amperes were secured. and the secondary of a radio- frequency small series voltage. By using an ex- This achievement suggests the possi- transformer, the primary of which is tra intermediate- frequency transformer, bility of using a less sensitive recording in the plate circuit of a radio -frequency (Turn to page ) RADIO AGE for October. 1925 The Magazine of the Hour 23 Experiments With Novel Antenna Systems

Solving the Antenna Problem for the Portable Radio Receiver by the Use of Ingeniously -Made Outdoor Antennae

By HARRY G. CARROLL .

The box -kite aerial is a most; efficient means of 'PHISHIS Summer's vast army of tourists open wire aerial, and not a loop an- erecting an impromptu antenna. Mr. Carroll's vacationists equipped with all tenna, the writer set out to devise a ,experiments with various antennae, during the past Summer, recorded in this article, should prove of manner and forms of portable radio number of truly portable receiv ing immense value to portable radio fans. receiving sets has shown what an import- set antenna systems, which wo uld ant part radio will play in the future satisfactorily meet conditions con- exists a number of suitable supports vacations and outings, and some atten- fronting the out -of -door radio to which it can be fastened. While in tion should be given to problems usually listener. the woods trees are most frequently encountered in the erection and opera- After considerable ex perimen- made use of as supports for the aerial tion of this type of receiving set. cation and testing with different wire and this practice will prove satis- No doubt, the readers of this article forms of antennae dur ing the factory if a clearing is picked out and themselves have had this question in course of a four weeks' radio ex- the antenna strung between two high their minds more than once, and it is perimental trip in the North trees. The antenna should be supported not an easy matter for the layman to Woods, the writer has come to from the very top and this can be easily devise and erect a truly portable antenna the conclusion th at there are accomplished without any climbing by system that will give efficient results three general ty pes of antennae securely fastening a stone or other under such varying conditions as are which are well worth t r y i n g object of weight to a stout cord and encountered on a Summer tour, or at when out on a touring or vacation throwing it directly over the top and the beach. trip with the portable as part of center of the tree. The weighted end The first and most difficult problem the equipm ent. of the cord will come down, thus allow- to confront the fan is a suitable support The fir st type of antenna to ing the aerial wire to be pulled up by for an antenna, high enough above the be desc ribed is the single wire fastening it to the other end of the cord. ground to reach out and bring in the horizo ntal aerial, which is un- Care should be taken not to pull the DX stations. It has been found in doubt edly the simplest and most wire up too far, so as to bring it in con- heavily wooded sections that trees and com monly used today, both at tact with any branches. The saine green vegetation absorb a vast amount ho me and in the field. This type procedure can be followed in elevating of the radiated signal energy and only is particularly adaptable in the the other end of the aerial wire. A the super power stations are able to tourist camp and in the woods. lead -in can be fastened to the center pierce this barrier and give satisfactory It consists chiefly of a single wire, or at the end of the horizontal portion results on the average receiver. To either flexible or solid, 100 to 12.5 of the wire. Only a very slight amount overcome this difficulty either a feet in length, both ends being in- of slack is necessary in the flat or hori- super sensitive receiver is necessary sulated by means of strain insulators, zontal portion of the antenna in allowing or the antenna must be in such a glass porcelain pyrex, etc. Height for swaying of trees to and fro in a position as to be above or away should be the chief object in the erection breeze. In fact, in several instances from this vegetation as far as of an antenna of this type, as it will no slack was allowed at all; even in a possible. be readily seen that the farther away heavy wind the antenna remained well the antenna wires are located from supported and no breakage occurred. Beach Aerials Rare surrounding objects, the less will be It was noted that the lighter branches THE beach offers another obsta- the shielding which they affect. at the top yielded sufficiently to pre- cle inasmuch as one se 1 d o m Although it is generally conceded vent any breakage of the aerial wire finds a support high enou gh above that the higher antennae pick up or or support cord. the ground to erect an antenna, it absorb more stray atmospherics or A good ground is equally as important is usually too conge sted to offer static energy than do the lower ones, as a good antenna and under ordinary much in this line an yway, so some they are undoubtedly the only ones conditions an iron pipe or rod preferably other means must be resorted to which will induce sufficient amount of galvanized, or copper coated, from unless one has a set that is sensi- voltage (EJIF) in the receiver to enable four to five feet driven in the ground tive enough to operate efficiently the distant stations to be heard. about four -fifths of its length, will with a loop antenna. This does Where broadcasting stations are within suffice. The ground lead running to not help ma tters much, since a a reasonable distance of the receiver, the set is wrapped around the pipe in recent ce nsus shows that the most naturally one should make use of a such a manner as to afford a good popular portable receiver lower antenna, as less static will be electrical connection. is of the regenerative type, picked up and the quality of the pro- It is advisable to drive the ground using three tubes. grams will be better. On the other rod in a low or moist spot if possible. Considering that the aver- hand, however, where long distance In the event that the ground rod does age tourist or camper stations are desired, the higher antenna not give satisfactory results, it may usually employs a re- is the only solution and the effect which be necessary to try a counterpoise. ceiving set which static and atmospheric disturbances have It is sometimes the case that a good ,.,y makes use of an on the received programs of course is ground cannot be established in this a necessary evil. manner due to geographic conditions, How the box -kits aerial is connected to the Using Tree Supports as it has been found that large areas ground. The ground pipe, which connects to the be have been either totally or set, is likewise connected to the insulator which in NAantenna of this kind can readily of earth turn is attached to 100 to 200 feet of antenna wire. erected at a tourist camp, as it partially insulated from the lower earth The kite cord itself, indicated by "X" in the draw- of rock. ing, should be able to stretch out 900 to 1,000 feet. has been found that there nearly always by stratas 24 RADIO AGE for October, 1923 The Magazine of the Hour The Fundamental Reason Why MORE and BIGGER

Technical Difficulties Super- Stations in Building Super Power Stations are Enormous; Some of the Satisfactory are COMING! Results Expected Soon

THE ultimate object which we hope range of the transmitter so that the current in the receiving antenna or to obtain by super -power broad- programs can be satisfactorily re- loop. This fact is mentioned for the casting is, of course, an appreciable ceived over a greater area, and hence benefit of those who might otherwise improvement in the service to broadcast provide better service both day and expect a signal strength greater than listeners. To what extent superpower night. the facts warrant. alone can accomplish this result has not At the present time, when the word, It is hoped and fully expected that been definitely determined. While some "super- power" is applied to so many the tests and development work now phenomena in radio transmission are projects, it is perhaps difficult for the being carried on will carry radio an unquestionably a function of the power broadcast listener to fully appreciate the appreciable step forward in overcoming of the transmitter, other characteristics technical difficulties that must be over- those things which are undesirable in arc a function of the frequency and the come in building a transmitter of this present day broadcasting. No one relative location of the transmitting size. Some idea of the problem may be doubts but that these problems will and receiving stations. gained from the fact that such a trans- eventually be solved to the entire satis- Realizing the limitations of the present mitter must be capable of receiving an faction of the broadcast listener. and appreciating the extremely small amount of sound energy, broadcast service, A Systematic Research vast amount of work that remains to be converting it to electrical energy, and accomplished, the General Electric Corn- amplifying it fifty thousand million ARADIO development laboratory for pany has established what is undoubtedly times without distortion. research on wavelengths from 5 the largest and most powerful broad- Some apprehension has been felt, and meters to 3,000 meters with power from casting transmitting laboratory in the suitably so, by the Department of Com- 5 watts to 100 kilowatts, has been con- world devoted to development work. merce, as to the use of appreciably higher structed on a 54 acre plot, two miles This laboratory is designed to permit power for broadcasting, believing that southwest of Schenectady, by the Gen- a thorough study of radio transmission it might result in the program of a super - eral Electric Company. in general, and broadcast transmission station crowding out the programs of This work of radio development is in particular. It provides equipment the lower power stations, particularly undertaken for the purpose of making a for obtaining the transmission char- in the vicinty of the station itself. systematic study of transmission phe- acteristics of wavelengths between 5 For this reason, the super-power sta- nomenon. Because of meager data, meters and 3000 meters, at powers up tion of the General Electric is located there is one group of scientists advocat- to 100 kw. In addition, there have several miles from the city of Schenec- ing super -power as the remedy for exist- been provided sufficient antenna struc- tady, so that the intense field, in its ing broadcasting defects; another, low tures so that the best type of antennas immediate vicinity, will not interfere power short wave transmission to ac- or radiators can be determined for the with the reception of other programs complish the same results; another various wavelengths. by the inhabitants of Schenectady. medium power, long wave transmission It is also for this reason that the and many different types of antenna A Enterprise Mammoth present series of tests are being carried systems are recommended, including rrHE laboratory occupies 54 acres of on at rather unseasonable hours, since the reflector, vertical, horizontal and 1 of land, and consists of 13 buildings, the license for the station is an experi- angular. three towers 300 feet high, one tower 150 mental one, and does not permit broad- On the plot near Schenectady are one feet high and a number of smaller towers casting during the normal broadcasting brick building, 60x100 feet, and four ranging from 60 to 100 feet in height. hours. The Company is in this way smaller frame buildings in which are From and between the towers is arranged co- operating with the Departmcnt of housed transmitters. There are three a network of antennas with which it is Commerce in an effort to get exact data steel towers each 300 feet high arranged hoped to secure fundamental data on on super-power broadcasting before it in the form of a triangle. This arrange- the most efficient antenna for a given is carried on during the earlier hours. ment permits the construction of many wavelength and power. The reports received up to the present different types of antennae. A fourth To return to the subject of what time from nearby as well as distant steel tower 150 feet high is used for super -power can do for broadcast points, indicate that no interference is smaller antenna structures. Three 80 reception: First, it is obvious that being caused by the use of super-power. foot wood masts support the antenna increased power at the transmitter In fact, many reports have commented now being used for the 109 meter trans- will provide increased energy at the on the extreme sharpness of the trans- mitter. receiving station, thus raising the mission. The largest building houses the power level of the signal above that of the It should be remembered that the equipment, high voltage rectifiers and noise. This should, to some extent, current in the receiving antenna is not amplifying and modulating equipment tend to decrease the effect of static directly proportional to the power of for the stations. There are three recti- and other disturbances; second, it the transmitter, but is proportional to fiers each having a capacity of 150 kw. may appreciably decrease the extent the amperes in the transmitting antenna, at 15,000 volts. These rectifiers convert to which fading interferes with re- so that the power of the transmitter the alternating current supplied to the ception; third, it may increase the must be increased four times to double (Turn to page 57) RADIO AGE for October. 1925 tl7iat the Broadcasters are Doing 25

At Last Sally Is Found

After years of tireless search, we've solved the question of what's become of Sally! Word comes from California Radio Stations that "Sally Bell," shown above in an exceedingly piquant pose, is capturing the hearts of the broadcast listeners by her eccentric programs with her trusty "uke." She appears most consistently at the Hollywood and Los Angeles stations. !Photo by wieseh 26 RADIO AGE for October, 1925 What the Broadcasters are Doing p,,; MIIIPIHI!I I , r,i

11 :4,?;_ What the 4;; y: .a. .. . broadcasters are Doing

Radio Puts Army, Navy and Editor of Radio Age on Marine Bands on Map Air from WLS WASHINGTON, D. C. -For years FREDERICK SMITH, editor the crack musical organization of the O of RADIO AGE, delivered an ad- country has been the U. S. Marine Band, dress to the radio public through the which began as a fife -and -drum corps in The attentive face above belongs to Frank S. Lane, microphone of WLS, the Sears -Roebuck 1798 came into fame with Sousa as regular announcer at KFR U, Bristow. Okla. He a station, from its Hotel Sherman and great favorite among the fans in the Middle West. studio its leader. More latterly it has been ably chiefly because his prime characteristic in announcing in Chicago, recently. Excerpts from his directed by Capt. William H. Santel- is- brevity. More power to him! talk are as follows: mann. The Marine Band has led more "Several years ago, when radio broad historic military reviews and inaugural casting was in the infancy of its develop- parades than any other band in the WBBM Starting Program ment 1 made a talk about the new United States. This red -coated organiza- art from this same room. After the tion has formed a picturesque background For Kiddies luncheon was over a good Rotarian for aocial functions at the White House. STARTING daily at 5:30 p. m., brother came to me and said: Sharing honors with the Marine Band Chicago Daylight Saving Time, "'Do you really believe, Smith, that during the past few years have been the WBBM is running a daily program for this radio fad is going to be permanent ?' Army Band, sponsored by General Per- the kiddies from their Broadmoor Hotel "I told him that in my opinion radio shing, and the Navy Band. When Gener- Studio. would grow to be a social and economic al Pershing, as head of the American It is in the form of a club meeting, factor far more important than he or I Expeditionary Force, returned from run by Joy - Digger, Tiny Dave, Uncle could at that time imagine. If that Europe at the conclusion of the war, Charlie, and various other performers. good brother is present today I want after hearing the famous Garde Republi- The club is known as the Joy- Digger to call his attention to the fact that radio caine Band of France and the Brigade of Club of WBBM, and the motto is: "Dig is now about the most continuously per- Guards Band of the British Army, he a little joy out of everything every day; manent thing we have around the house, set about having a band organized from it's there if you only dig deep enough." with the possible exception of the tax col- army bands in this country that would The programs of the club will consist lector. We get the setting up exercises in equal these famous organizations. of songs, stories and instrumental num- the early morning to keep us thin. Later However, until radio came in, there bers, many of them put on by the kiddies the cooking lessons tell us how to eat and was a tremendous handicap in Washing- themselves. One program a week will wax fat. The forenoon brings us the mar- ton, their home, with regard to the be taken over by the various members of kets and household hints. Noon brings M arine, and Army and Navy bands. 1 t was the Boy Scout Troops of Rogers Park. the organ recitals and other features. In because they were the afternoon are so seldom heard. the concerts and True, during the general programs. Summer months At twilight the there were con- bedtime stories certs on the White and lullabyes and House lawn, the from then on there Capitol, and other is jazz until such places. Again there hours as all honest were concerts in people should be the Marine Bar- abed. Wake up in racks, so remotely the middle of the located as to be night if you choose difficult to find and and tune in on 536 in an ancient band meters and you stand in Potomac can hear the World Park, a mile from Crier telling about a car line and al- the latest develop- most inaccessible ments in the Mor- to the visitor. oroccan situation. Radio, howev er, I'll say radio is has changed it all. permanent! It is The three great so permanent that service organiza- it makes a noise on tions are now reg- our so- called silent ularly heard on Monday nights. the air and by the But when one of us No, this is not a scene along the European Riviera; it is just a view of the coast -line tunes in another hundreds of-thou- which will soon be the home of KT NT, about to go on the air at Muscatine, Iowa. KT NT sands of citizens is said to be one of the most beautifully located stations in America. Its towers, location tunes out and there throughout the of which is indicated by the arrow in the picture, will tower 150 feet above the Mississippi. is always s o m B- country. with a view of 50 miles in all directions. one listening."

RA DIO AGE rnr,ch-tulirr, 14 1; !Ural !hr Broadcasters are Doing

mr's r'rr 17 .

r.

Now we BELASCO Have of "The Radio"

The girl Behind the Scenes at Station WTAM

HONORS just naturally gravitate ticularly desired artist will appear on toward the deserving and that is By P. A. PRICE schedule time. Artists are proverbially why Miss Ruth King, of Cleve- tempermental and this applies to their land, Ohio, is claiming the attention and life. However, it would seem that the punctuality as well as their dispositions. admiration of broadcasting stations and young lady was destined to be a Program Once upon a time this did happen in broadcast listeners alike, and has been Director for, when the Cleveland Plain the studio and bliss King, in looking called "The Belasco of Radio." Those Dealer opened its studio for Station about for the next artist to appear, famous "Nite Cap" programs that are WTAM it was Miss King who was called found herself deserted and alone. The broadcast on the first Saturday of each upon to arrange the programs broadcast situation was tragic, but instead of losing month from WTAM; the luncheon from that remote control equipment. her head bliss King used it and calmly concerts that are on the air from this Then the Plain Dealer, with other Cleve- announced that the next number would station every day except Sunday; the land newspapers, gave up association be a piano solo by "Miss Betty Parker" Wednesday evening dinner hour of music with the radio stations and the Euclid and then as calmly seated herself at the -all the details of these entertaining Music Company took up the good work piano and provided the solo herself. programs are arranged by the little lady and placed Miss King in charge as Pro- Since then "Miss Betty Parker" has in the accompanying photograph. And gram Director of their station that is played several accompaniments, thus now she has been called upon to serve operated by remote control from WTAM. proving that a dual personality is very on the Program Committee of Cleveland's It was a choice well made, for the young handy to have in a broadcasting studio. first annual radio exposition which is to lady's programs were a success from the Ruth King is building a big future for be held in the public auditorium from first. herself by developing her administrative November 7th to the 15th of this year. We who listen in have small idea of ability. With youth, energy, ambition The holder of many medals for tennis the effort involved in arranging for a and ability to drawn upon, Ruth King championship, editress of a society paper daily program or for such special feature will go far in the field of radio broad- devoted to country club affairs, an programs as are offered by the "Nite casting and with her will go the best accomplished musician and composer, Caps." If Miss King's expression is wishes of a legion of broadcast listeners Ruth King has crowded a host of success- just a trifle pensive it may be due to a who look to her for their entertainment ful efforts into a few short years of public natural worry as to whether some par- and have yet to be disappointed. 28 RADIO AGE for October, 1925 What the Broadcasiers are Doing "The Radio Boy Wonder" of Hollywood

How a Mere Youngster Started a Radio Station in America's Most Interesting City, Which Is Destined to be America's Most Interesting Contribution to the Radio Art

By C. CLYDE COOK "The Town Crier of the Day "" at KNX, "The Voice of Hollywood, "" with Little Jean, 5- year -old mute girl who is learning to talk and hear by radio.

SITUATED in the "Heart of Holly- took a postgraduate course in Columbia. encourage her in every way possible." wood," Station KNX, the Los Recently Guy C. Earle took over the It was too apparent that this announcer Angeles Express, is generally con- management of the Los Angeles Express, was gifted with a magnanimous heart. ceded to be one of the most popular sta- but the station KNX will ever remain The demonstration with this once deaf tions on the entire Pacific Coast, because his chief concern, for there is something and dumb little girl was astounding, and of the clarity of reception, superior tone so human and vital about this young yet it only proves what marvelous things and the high standard of programs that newspaper magnate that he derives more can be accomplished by radio. This bring within their scope the interests of joy from broadcasting cheer- inspiring much the "Radio Philosopher," G. all radio listeners -in. programs on the air than from hoarding Allison Phelps, now the Town Crier of "So This Is Hollywood!" can certainly up more of this world's goods. the Night Watch, conceded with his be applied to Station KNX, for this infectious smile. The "Radio Phil- A Real station has the distinction of broadcast- Miracle osopher" has a magnanimous heart, ing more screen talent, perhaps, than oNE of the most trenchant reasons also, and his philosophy of life is abso- any other station in America. why Mr. Earle derives great pleasure lutely an inspiration to all who hear his Because of its convenient location from this station is because a modern lectures over the radio. When he lost to the homes of many of the world's miracle is being wrought at KNX, doing his devoted mother five years ago he most famous artists, musicians and what the science of medicine and surgery felt for a time that life was not worth people of national and international could not do -give hearing and speech living, but finally he worked out a philos- fame, who naturally accept KNX as to a little girl, born deaf and dumb. Mr. ophy which has brought many a radio their "home station," they are irresist- E. J. Albright, Town Crier of the Day convert out of the "dumps" just as it ibly attracted to the KNX microphone Watch, detailed the miraculous cure did Phelps. by the quality standards of broadcasting being perfected by means of the radio. The "Radio Philosopher" has become maintained there. And, though the "When this little girl, Jean Marie Mac - so in demand, since his lectures delivered station will be only a year old in October, Williams, first placed the head phones over KHJ, the Los Angeles Times, that KNX already has a greater following on her ears she caught the sounds, and station KNX suddenly annexed him of radio fans than stations many years began to give audible proof of it in trying to their present talented staff, of which its senior. to repeat some of the major chords .of Carrie Preston Rittmeister, most able And who was responsible for this great sound, with their variations. Taking accompanist and program manager, is station? An admirably gracious young her to an eminent physician they learned one of the foremost members. Mrs. man of about thirty years was instantly that Jean Marie possessed a very un- Rittmeister also came from station KHJ, pointed out as the founder of this unique common sense, 'bone conduction;' i. e., where she had served in the same capac- institution. But, try as we might, we the bone picks up tone and it registers ity and observed Queen Titania deliver could not get Guy C. Earle, nephew of by vibrating against the auditory nerve. her initial program with her father, the Mr. E. T. Earle (former owner of the "Later her parents brought little Jean Sandman. L. A. Express), to divulge any informa- Marie to the KNX station and finally I No program arranger ever guarded tion concerning his own participation evolved a plan by which I believe Jean the standards of their programs more in KNX. From other sources we learned Marie will succeed in overcoming her zealously than does Mrs. Rittmeister. that Guy C. Earle attended the common handicap. I proceed to ask her very simple This can be easily attested by the thou- schools in Oakland, and, after graduat- questions and she has progressed so well sands of radio fans throughout the United ing from the University of California, he that she usually answers correctly, and I States, who are so fortunate as to be 9 RA 1) 10 AGE for l )ctober, 1925 What the Broadcasters are Doing enters able to tune in on her incomparable into these broadcasting programs programs. And here is a sample of the is actually an inspiration to those who pleasing variety of her inimitable pro- are fortunate enough 'to hear her. grams: 7:30 a. m. KNX morning gym, Miss June Pursell, heralded as the directed by J. C. Casey, physiotherapist. KNX Radio Girl, and who has now gone on the Orpheum Circuit of Vaudeville 8 a. m., inspirational talk and morning prayer; 9 a. m., time signals from Wash- to entertain vast audiences with her ington; 10 a. m., Town Crier of the Day's resonant voice, possesses such a deep, morning message; 10:30 a. m., Kate masculine voice that she has often been Brew Vaughan, director of household mistaken for a male broadcaster. How- goes Mrs economics department of Evening Ex- ever, this only to prove that press, gives lecture; 11 a. m., nature talk; Rittmeister is ever vigilant to gather into the fold of KNX station a galaxy m. to 1 p. m., Wurlitzer organ recital; 12 of stars which will give the thousands 3 p. m., talk by Chef de Cuisine; 4 p. m., Metro-Goldwyn -Mayer Studio program. of radioland listeners -in the greatest possible variety of talent, coupled with 5 p. m., market reports; 5:30 p. m. to 6:15 p. m., sport talk by Sid Ziff, sporting the best obtainable degree of high stan- editor of Express; 5:55 p. m., the Town dard of quality. Tattler, 6:15 Alder Travelogue; 6:30 KNX is on the air more hours, perhaps, than any other station in the United p. m. to 7 p. m., Atwater Kent orchestra; States, since they start the day off with 7 p. m. to 7:30 p. m., Ambassador Hotel gym in the morning, concert orchestra; 7:30 to 8 p. m., talk instruction at 7:30 and hundreds of pouring into the on the Movies by Norma Talmadge; letters studio daily, attest the value this physical 8 to 9 p. m., Venice of America band; Town Crier of the Night Watch; 9 to 10 exercise has been to many converts of radioland. And few stations can com- p. m., Abe Lyman's Cocoanut Grove with KNX for variety of program. orchestra; 10 to 11 p. m., Hollywood pare night, with celebrated stars being intro- So if you want a real air -fest, every hour duced; Town Crier of the Night Watch. of the day, just tune in on station KNX, And thus concludes an all -day program the Los Angeles Express, Hollywood, California. of greatly diversified entertainment, in- etc., the equal of Miss Marguerite Rickard, lyric soprano of struction, inspiration, KNX, and exceedingly easy to look at. which is hard to find on any other broad- Miss Rickard's brother, Vernon Rickard, is Radio Problems Explained at cast program. Another reason for the announcer at WGN, Chicago, so it must Convention unusual quality of the KNX programs run in the family. orchestra of Calmon CHICAGO, ILL. -Radio interference, is the famed string the development and use of the radio Luboviski, who was born in Chicago picture, and portrays her extensive work vacuum tube and design of radio re- of Russian parentage, and later became in the cinema drama, radio fans through- ceivers were subjects touched upon at the one and only pupil of the interna- out the United States will again experi- the sessions of the Third National Con- de tionally famous violinist, Ference ence one of the many innovations which vention of the American Radio Relay Vecsey. After eight years of intensive League at the Edgewater Beach Hotel in has made KNX the peer of all stations this city. Outstanding figures in each of study under this master's guidance which specialize in studio talent. Miss returned to America, en- three divisions of radio science presented Luboviski Talmadge has a clear, bell -like voice, papers for the information of the several trusted with the master's secrets of tone and the enthusiasm with which she hundred transmitting radio amateurs and technique, where he electrified large attending the gathering. audiences in the largest symphony or- Professor W. J. Williams of Rensselaer chestras of the United States. Polytechnic Institute and director of radio broadcasting station WHAZ of A Tireless Worker Troy, N. Y., covered the information now SINCE last September Luboviski has available about the various types of hundred concert engage- radio interference. He told of his ex- filled two periences with power, telephone and ments, and this tireless genius is now telegraph companies in attempting to broadcasting exclusively over the KNX run down radio interference. He touched broadcast station in conjunction with upon the influence of the vast number of the world -famed Luboviski trio, consist- power lines in the country, pointed out ing of Mischa Gegna, cello soloist, Joseph some of the difficulties experienced with Vecsei, pianist soloist, and Calmon electrical appliances and vehicles, such Luboviski, violin soloist. And Lubo- as trolley cars and electric railroads. needs A detailed explanation showed that all viski's Russian string quartette of these sources were contributing some- no introduction to radio fans throughout thing to the vast total of interference. the United States, as they have broad- Prof. Williams' paper was based upon cast from several hundred stations in perhaps the most exhaustive research the few short years of their existence. made on the subject. Working with the Another shining star in KNX's con- various other users of electrical energy, stellation of radioland's luminous firma- he has come into contact with practically ment is Raquel Nieto, coloratura soprano, every known cause of interference. J. C. Warner, in charge of small tube one of the most marvelous voices heard development at the General Electric in radioland, and discovered by station Company Research Laboratory, drew KNX. She has been acclaimed by her upon his store of experience gathered in most discriminating listeners as a future the years during which vacuum tubes Galli Curd, and in view of the fact that have made such tremendous strides. Miss Nieto is but twenty years of age He announced the completion of work this is quite commendable. Hailing tending toward a standardization of tube from Mexico City, this titian-haired, bases and sockets, a matter that has in Guy C. Earle, Jr., the "Boy Wonder of the past made necessary structural alter- blue -eyed Spanish artist has a great Hollywood" who is manager and owner of ation to meet many desired changes. future in store for her. KNX, the Los Angeles Express Station. The demand for a dry battery tube When Norma Talmadge appears in It is due to his efforts that KNX has become that will supply sufficient undistorted the KNX studio in the near future and one of the most widely known radiocasts in audio frequency to operate a large loud broadcasts the marvels of the moving the country. speaker bas been met, Mr. Warner said. 30 RAM ACE for October, 1925 What the Broadcasters are Doing

How Quality, Super -Station Reliability,

The upper photo shows KYW s station along the east wall, looking south. To the right are seen the control board, modulator panel, oscillator KYW Achieves panel and tuning panel. In the circle is Walter and POWER C. Evans, chief engineer of the new KYW. KDKA'S SISTER STATION OPENS ON CONGRESS HOTEL, CHICAGO

THE principal considerations striven tors reach their full voltage, relays in the for in the design and installation By Walter C. Evans filament lines make contact, the next of the new Westinghouse Station circuit breaker does its bit and the 60 KYW on the roof of the Congress Hotel cycle rectifier for the grid bias and were perfection of quality, reliability, the local public service company over another small rectifier for the plates and reserve power. The resources and two separate transmission lines from of the fifty watt amplifier tubes add their best engineering skill of a great company different generating stations. This gives energy to the circuit. If everything to have gone into the new equipment in 100% insurance against power line this point has taken place to the satis- order that the vocal solo or complex interruptions. A 100 kilowatt trans- faction of the control panel, it allows orchestration may be turned over to a former sub -station has been built the large contactor to close and current discriminating public, identical with the in the basement of the hotel where the is furnished to the bank of 22,000 volt original sound. transmission lines are stepped down to transformers outside the station room. Years of experience in the design of 220 volts and carried through large Should anything be amiss while this electrical apparatus is apparent in the capacity cables to the radio station on procedure is going on, the contactor well arranged panels, the easily accessible the roof. These are connected with a will remove the offending apparatus from units with everything in duplicate so power distribution board or feeder the circuit and start over again. that program interruptions due to elec- panel through which all of the different trical causes may be reduced to an abso- pieces of apparatus draw their source The Big Transformers lute minimum. of power. This panel also carries suit- THE four 10 kilowatt, 22,000 volt Considerable more power is provided able cut -outs to open the circuits and transformers outside the station are for than will ever, in all probability, be shuts off the current should accidents connected with the two transformers in needed for ordinary broadcasting. This occur to the different machines. parallel on each phase and the output, is a desirable feature, for it is a better Next in line is the contactor panel, is connected to four water -cooled kene - operating proposition to run a large which does the thinking for the set tron rectifier tubes, which give full piece of electrical equipment at a frac- (and, if necessary, for the operator). wave rectification on two phases with a tion of its capacity than to overload a It is so arranged that the operator need resulting pure direct current at voltages small installation. This will leave a only press one small push button and up to 10,000. The out -put of the rec- large margin of reserve power in case of in slightly over 10 seconds the whole tifiers pass through a bank of high voltage national emergencies, paralysis of tele- station gets under way. The push button choke coils and condensers which smooth graph and telephone lines or similar first energizes the water pump which out the direct current until it is free contingencies. forces a stream of cold water through from the slightest traces of ripple or hum. To get a good working idea of this the jackets of the tubes. When the This current is fed to the four water- Leviathan of the radio field, we will water pressure comes up to a pre- deter- cooled modulator tubes and to two water begin with the primary source of power mined value, it allows the next contactor cooled oscillators. The oscillators work and follow it through to the antenna. to operate which starts up the filament directly into a "tank" circuit which Current at 4400 volta is obtained from motor generator unite. As the genera- (Turn lo page 62) RADIO AGE for October, 1925 What the Broadcasters are Doing 31 11 They Never Run Out of Ideas in This Radio Game

The FIRST By MARY JANE CHILD LAWRENCE Announcer

Between Announcing and Acting for the So- Called Cinema This Kid is Very Busy! You may not believe it, but "Dicky" Brandon, shown above in a Witzel photo, is a coming movie star- second only to. the famous Jackie -and he has Jackie beaten in that his the only professional radio announcer among the kiddies -that we know of, anyway. Were open to disputes, however.

IT SEEMS as if there's something plain kiddish nonsense, so he had no star or a radio announcer. Right now new under the sun every day in this trouble in getting booked for programs he's lying awake nights wondering just interesting radio game. The latest with the best of them. what to be. You see, a man in these thing -and it certainly is deserving of That was four months ago, and today days has gotta work hard to support mention -is the advent of a young movie Dicky spends most of his time announcing his father and mother. And at the age star into the ranks of dyed -in- the -wool, via radio and the rest of his time -really of six Dicky Brandon realizes he's professional announcers. his "spare- time," playing juvenile leads getting old and must look to the future. Heretofore most of the country's famed for several movie companies out where Do you blame him? announcers have impressed us with their the oranges grow, and where it never He tells us that he stays awake nights maturity and staid indifference; viz., rains except on unusual days. pondering over his career. But we have J. Andrew White, Graham MacNamee, How did it come about? Well, half a mind to believe it's the income and others. But what does young Dicky dearie, Dicky just horned his way into tax. Brandon's press agent do but put some the announcing game, to use a plebeian He Does His Stuff cute knickers on his youthful form and expression. And once he got into it, made him the most famous of all an- he found it well nigh impossible to get RECENTLY Dicky demonstrated he nouncers- overnight! out. He had a habit of stopping in the could do anything in the radio line You see, it's this way. Dicky is a middle of his programs when he was by taking over the entire direction of a movie actor by trade. He lives in first beginning, and carrying on an infor- Los Angeles station for one evening, Hollywood, Los Angeles and New York mal chat with his potential listeners. when he was announcer, director, pro- at specified periods of the year, and gram arranger, office boy, and what -not. Dicky rounded up his own gang of though he's but six years of age, he A Modest Youth knows his stuff and is looking covetously juvenile entertainers one evening at 7 at the Juvenile Movie Crown now held OF COURSE, such a procedure made o clock, just before the sun went down, by Jackie Coogan, the original Kid. a "hit," and although Dicky persist- and from 7 to 8 o'clock it was "Dicky's And it's safe to say that Dicky is at ed that he was just doing what he'd hour" in every sense of the word. Kid least second to Jackie. heard other announcers doing, he was songs, monologues, foolishness and child- told his extreme youth made it seem ish laughter rippled out on the radio original, even if he claimed it wasn't. waves -the first "stunt" of its kind ever "First in Something" So Dicky was won to radio and the produced. NOT to be outdone by holding a "experienced" announcers gnashed their After the evening s entertainment second place, however, Dicky de- teeth and took a back seat. Dicky was literally snowed under with cided to be first in something-and From a personality standpoint, Dicky's congratulatory telegrams, phone calls after a couple of visits to radio studios a wow. The picture shows him as Little and special messages-all attesting his on the Pacific coast, he decided his forte Fauntleroy, but that's only in the movies. inborn ability as a "radio genius extra- lay in that direction. Dicky is par- He'll probably grow up to be a he -man, ordinary" at the tender age of six years! ticularly adept at elocution, singing, and if he decides whether to be a movie (Copyrighted: 1925 By Radio Age) 32 RADIO AGE for October, 1925 What the Broadcasters are Doing Radio Interests Clet Together RADIO COUNCIL PLANNED Radio Manufacturers' Association Starts Drive to Unite all Radiodom in One Common,Constructive Purpose

THE organization of a National to be proposed. The industry can pro- shows civic events. For the same reason, Radio Council to include represent- tect itself only by organizing the listen- we believe that special effort should be i atives of the manufacturers, job- ers, the dealers, and the jobbers in every made by the management of all shows to bers, dealers, broadcasting, agricultural state, and leaving the matter to them. insure the attendance of school children interests, trade papers, listeners, and This is what the automotive industry through the inducement of specially others interested in radio, is being plan- has done. priced tickets, prizes for home built ned by the Radio Manufacturers' Associ- "In connection with the broadcasting radio apparatus, etc. i ation as the result of a report made by situation, this committee suggests that "This committee also recommends that Frank Reichmann, chairman of its com- members of the Association who operate the association take up the matter of mittee on publicity and public relations. broadcasting stations immediately be re- further encouraging the teaching of radio l\Ir. Reichmann in his report says: quested to organize a broadcasting divis- in all manual training classes in all "All listeners organizations, especially ion of this Association. public and private schools. the American Radio Association and the "Closer affiliation of all the local radio "This committee believes that by care- Broadcast Listeners Association of Amer- trades association would also make it ful, conservative action during the com- ica, should be invited to hold their next possible to carry out an organized cam- ing year, a great deal can be done to convention at the same time and place paign to increase the sale of radio cement together all those interested in as the RMA. apparatus. We believe that the manu- radio, to the end that the industry will "Every broadcasting station should be facturers' association should outline such be better prepared to repel legislative invited to send a delegate to a meeting of a campaign and suggest it to the local and other attacks, and that even broadcasters to be held at the same time. association for the latter's use. One greater public interest in radio will be "All local radio trades associations thing in this connection would be a group assured." should be asked to send delegates to a advertising campaign of the dealers, in The report was approved at the similar meeting, probably under the each city, using advertisements which Atlantic City convention of the RMA auspices of the National Radio Trades would call attention to the more import- and the work of organizing a national Association. ant special events to be broadcast by the council is already under way. "The publishers of all radio trade stations in the immediate locality. The following officers elected at the papers should also meet at the same time Closer affiliation between the broad- recent RMA convention in Atlantic and organize their branch of the industry. casters, trade association and the manu- City will meet on Tuesday evening, "I especially want to call attention facturers would help a great deal to carry September 15, to consider plans for great- to the necessity of organizing the radio through campaigns of this kind. ly broadening the work of the Associa- listeners throughout the country. The "This committee recommends the tion: experience of the National Automobile establishment of a National Radio Coun- President- Herbert It Frost. Chamber of Commerce is one by which cil to be composed of representatives of Secretary-Carl D. Boyd. we can profit. The automobile manufac- the Radio Manufacturers' Association, Treasurer -S. I. Marks. turers, as a body, were unable to compel the dealers and jobbers, manufacturers Directors At- Large- the construction of hard roads, or carry agents, the broadcasters, the radio paper Powell Crosley, Jr., First Vice Presi- on legislative reforms which are vital to publications, and the listeners. dent, Harry L. Bradley, L. G. Baldwin, the industry. By supporting the Ameri- "We are advised that the National Edward H. Jewett, E. T. Cunningham. can Automobile Association, composed of Radio Trades Association. which has Directors Eastern Division - car owners, this work was all carried out done much excellent work in the past, is Godfrey Gort, Second Vice -President, in a very satisfactory manner, the manu- anxious that the manufacturers get H. H. Eby, Alex. Eisemann, R. E. facturers giving their support to the behind an organization of the dealers and Thompson, James L. Schwank, A. U. "Three A's ". A great deal of similar jobbers. We are also advised that the Howard, S. B. Trainer. work can be carried on through the local National Association of Broadcasters is Directors Western Division - radio trade associations, which have been willing to help in organizing a central E. N. Rauland, Third Vice -President, or are being, organized, in practically council, and we are assured that we will A. J. Carter, Frank Reichmann, J. M. every city in the country. Also, it would have the active support of the two lead- Stone, H. H. Frost, W. H. Huth, John C. he to the advantage of the entire industry ing listeners organizations -the American Tully, L. E. Parker. to have all these radio trade associations Radio Association and the Broadcast welded into some national body which Listeners Association of America. IT is planned that the eastern and can cooperate with the manufacturers. "We are also of the opinion that the western boards and members meet at The same applies to the publications and American Radio Relay League should regular intervals in New York and the broadcasters. be invited to become a member of the Chicago while the entire board will its meetings between the two Harmful Laws Feared council and we can assure you at this alternate time that the Farm Radio Council will cities. Many problems of tremendous IWISH to emphasize, at this time, the become an active member. importance to the industry are now in fact that this Association cannot now, "Inasmuch as all radio shows are pri- the hands of the committees and action and probably never will be in a position marily advertising and publicity features, is expected during the New York meet- to, watch for and guard against the this committee believes that special ings. These board and committee passage of hostile and harmful legisla- attention should be directed by all show meetings will culminate in a general tion in the assemblies of the entire forty - managements to obtaining the coopera- membership meeting on Thursday even- eight states. Such legislation is certain tion of public officials in making the radio ing, September 17. Ti

RADIO AGE for October, 1925 The Magazine of the Hour 33

The Latest in Radio Construction Single and Dual Controls for 5 -Tube Sets

By JOHN B. RATHBUN

Copyr:cht: 192S THERE has been much argument of divisions will now be available. Here, late on the subject of simplifying the necessity for uniform station distri- the wavelength tuning controls on bution over the scale applies with triple five -tube radio -frequency receivers, re- Timely Set Builders force, and with approximately six sta- ducing the conventional three controls tions to each of the 100 dial divisions, to one or two dials. While there is Will Welcome Novel extreme care in adjustment is necessary. much to be said in favor of the simpler Each wavelength must be absolutely control system, it is not all pure gain, definite within less than one -sixth of a for the reduction in the number of dials Idea to Simplify the dial division if we expect to tune in each is attended with certain difficulties often of the 600 or more broadcasting stations overlooked by the adherents of the single Tuning of R. F. Sets now licensed without the further correc- and dual control that will be evident on tion of a second or third dial. a short study of the proposition by an With less than three controls, highly unbiased investigator. Mechanical sim- selective tuning units are necessary to plification is often attended by certain three, the stations will no longer be prevent the overlapping of signals lying practical psychological problems which tuned in over so wide a range of scale within a few meters of each other. It is in turn depend upon the state of mind divisions, and instead of being in evi- absolutely essential that the inductances of the operator. dence over five dial divisions as before, be immune to external fields and influen- Under ordinary conditions, selectivity the band will be reduced to approximate- ces and that they act only on the im- increases with the number of tuning ly three divisions. Thus, the tuning is pulses received through the antenna units employed, and with the three tuning more critical and requires closer and system. Further, there should be some controls ordinarily employed on five -tube more careful dial adjustment than when means of adjusting the sharpness of the radio frequency receivers a high degree of the three dials are employed. tuning within the set so that it can be selectivity can be attained without mak- There are fewer dials to look after, closely adjusted to meet local conditions. ing any one of the controls unduly crit- that is true, but on the other hand it is It should be fairly broad out in the ical. For example, with three controls, more difficult to separate stations lying country where there is little interference each of the individual units can be quite close together in regard to wavelength, and should be capable of a considerable broad yet collectively the combination and the effect of bunched stations on the sharpening in districts where there are results in excellent selectivity for each lower wavelengths is more difficult to many strong local stations. of the units corrects and augments the overcome. Two dial control absolutely Now comes the counter argument that effects of the unit going before. Under demands modern variable condensers of it is easier to make close sharp adjust- ordinary conditions, using three dials, a the straight -line- wavelength or straight - ments on one or two dials than it is to station may come in with fair volume line- frequency type by which the stations make fairly broad adjustments on three over five divisions or more on each of the are distributed over the dials with greater dials. Well, perhaps it is under certain dials and yet the set as a whcle will be uniformity than with the old straight -line conditions, but to my mind it is largely extremely sharp. If one dial tends to be capacity type having simple semi -circular a matter of personal taste. It depends very sharp and critical, the effects can plates. Two dials are more easily moved upon whether the individual prefers to be modified by making adjustments with together or "tracked" than three dials, make three rather broad adjustments or the remaining dials. but the tracking must be done more only one or two sharp and accurate ad- Now let us assume the same degree of accurately. justments. At first glance it would seem total or overall selectivity with only two With a single dial control still more that the single dial system would be the dials operating the former three tuning accurate adjustment will be required (m- ideal proposition, and so it would be if units through gearing or similar mechani- a given selectivity, for instead of coming there were only 50 to 100 stations spread cal connection. As the total movement in over five dial divisions as with the well over the length of the dial, but owing must be had with two dials instead of three dials, only one -third the number of (Turn to page 36) Blueprints Explaining the Single and Dual Controls on pages 34, 35, 38 and 39 RF-Z

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COPYR/6HT /925 Rivo/0.4 E,/NC P9T.hBU/ C///CAGO, /LL . .B,,PFT --/OOO 36 RADIO AGE for October, 1925 The Magazine of the Hour (Continued from page 33) gears (G1- G2- G3)are fastened on the con- simple condenser is installed for the third to the present congestion this is far from denser shafts aabefore, but are connected tube; making two controls necessary. being the case. Stations bunched at the together by small intermediate pinions The panel space required is only that of ends of the dials, and varying only by (Pl) and (P2). In the first place, the a single condenser, but the assembly of ten kilocycles from one another, makes diameter of the gears is considerably course extends farther back into the single dial adjustments rather difficult. reduced by this method, thus making it cabinet than with a single condenser. a simpler matter to mount the apparatus Tuned R. F. Circuits Fig. 5 shows a "three- gang" condenser on the panel. Secondly, by making the with three independent stators (ST-1, BEFORE the various tuning methods diameter of pinion (PI) exactly half the ST-2, ST-3) and a single rotor (R). be in detail, it will diameter of the gears (GI-G2-G3), the With this assembly it is possible can taken up be dial on of (P1) to tune advisable the circuit diagram (D) mounted the shaft all three stages of the circuit of Fig. 1 to examine will 360° instead of through * of a conventional two stage radio fre- turn through by a single tuning dial mounted on the quency circuit so that the conditions 180° and this will doubly spread out the end of the rotor shaft. A condenser of can be more fully understood. In Fig. stations and facilitate tuning. this sort takes a panel space equal to It is evident a full 360° turn will 1 is shown the circuit of two tuned radio that that of a single condenser, but it is so frequency stages and detector, the radio reduce the number of stations per dial long that it generally extends the full tubes being at (RF-1) and (RF-2) while division and thus will eliminate over- depth of the cabinet. However, this is the detector tube is at (DET). All lapping and will make the set correspond- not a serious objection as the tube sockets ingly more selective and less critical. can be rearranged without three tubes are tuned accurately to system with trouble. wavelength by the three variable con- In effect it is really a vernier It will be noted that small compensat- densers (C1- C2 -C3) connected across the an increased active arc of dial, thus at least partly offsetting one of the bad ing condensers (V1) and (V2) are con- secondary windings of the air -core radio The small nected between the rotor and stator f requency cou piers or transformers (L1 -L2- features of single dial control. compensating adjustable condensers are plates in both cases for balancing the L3), and as shown in the diagram, these capacity of the stators as previously ex- condenser adjustments may be individual at (VI) and (V2) as before, for balancing up unequalities in the main tuning ele- plained. One such compensator is used or else they can all be adjusted at one for the two gang condenser and two com- time by means of certain mechanism ments. In case where a 180° dial is desired, it can be mounted on one of pensators (V1) and (V2) are employed about to be described. on the three gang type. Usually, the It is important to note at this point compensating condensers consist of a pair that the (F) ends of the secondary coils of small adjustable leaves mounted are all connected to a common wire, the directly on the condenser and built into (-A) line and ground connection, and it so that separate condensers are not that all the rotors of the variable con- NOTICE! needed for the purpose. As they need densers are therefore also connected to adjustment only once after the set is this ground (-A) wire. The stators of built, there is no necessity of mounting the condensers are connected individually Full Details of the New dials for the compensators on the front to the grids (G) of the three tubes. This panel. makes "gang condenser" construction possible. A single rotor element can be "RADIO AGE Self- Contained Field Coils used for all three stages meshing with three independent stator units, and all ANY air -core radio frequency coupler units can be used with one tuning dial RECEIVER" and transformer can be used in con- attached to the rotor shaft. nection with the gang and geared con- One method of single dial tuning is to densers. It is possible to pack such couple the rotors of the three variable To Be Announced Soon coils into a very small space without condensers (C1- C2 -C3) together mechan- back -feeding between stages. ically by means of gear wheels at (Gl- Will Be Given A single circuit coupler is shown by G2-G3) shown in Fig. 2. The electrical Fig. 6. It consists of a single continuous connections are made exactly as in Fig. winding which terminates at the poste 1, and one movement of the dial (D) in the (G) and (F) and is tapped at the points mounted on the center shaft of condenser (tl) and (t2) for the connection of the (C2) tunes all three stages simultaneously. November Issue, antenna. The schematic diagram of the While this does not simplify the tuning equivalent solenoid coil is shown by units to any extent, yet it does reduce Fig. 6A which is lettered to correspond the dial control to one operation and for Out October 15 to the coupler drawing. This single cir. this reason the arrangement has proved cuit coupler is used for the antenna coup- quite popular. ler as installed at (LI) in Fig. 1, and the At (V1) and (V2) are two variable two taps (A1) and (A2) provide for condensers of very small capacity used the condenser shafts as before so that different degrees of sharpness or broad- for balancing the condensers (C1) and it will turn at the same rate as the conden- ness in the tuning. (C3) so that all of the main condensers ser plates. Approximately 200 turns of No. 24 D.S. are of exactly the same capacity and so Condenser Control C. wire, 134' in diameter is used for mak- that they will all accurately "track" with Gang ing the coil. Tap (t1) for terminal (Al) is one another at any given dial position. GANG condensers consist of a single taken at the sixteenth turn, while tap When once adjusted, the balancing or assembly made up of two or more (t2) for terminal (A2) is taken at the compensating condensers (V1) and (V2) electrically independent stators and a sixtieth turn. Some little experimenting need no further attention. This, or an single rotor which meshes simultaneously will be required to balance up the coil equivalent method, must be used as the with all of the stators with a single dial properly in order to cover the band of commercial variable condensers never movement. The principle on which this broadcasting wavelengths ranging from have exactly the same characteristics system works was suggested in the para- 200 to 550 meters when used in connec- when purchased on the open market, and graph dealing with the circuit diagram of tion with a 0.00035 mf. variable con- it is imperative that they act in exact Fig. 1 where it was stated that the rotors denser, and for this reason it is better to unison on the turning of the dial. of all variable condensers are connected purchase the coils than to attempt The gears (G1- G2-G3) are made of to the common (-A) line. The use of a their manufacture at home. When a fiber or other non -conducting material, single rotor greatly simplifies the con- solenoid is bent into a toroidal form, it and are provided with a means of fas- struction, and in many cases takes up does not follow the same laws as it did tening them tightly to their respective less space -at least panel space. when used as a straight solenoid. condenser shafts without danger of slip- A two- gang' condenser is shown by Antenna connection (AI) gives ex- ping. The diameters depend upon the Fig. 4 where the two independent stator treme sharp tuning, for the coupler then center-to- center distance between con- units (ST-1, ST-2) are carried by the acts like an auto -transformer with a high densers, but in all cases the diameters frame (e-f), and where a single rotor on ratio between the virtual secondary and and numbers of teeth must be the same the shaft (R) meshes with both stator prima coils. Connecting the antenna on all gears. If there is a variation in sections. The stators, are of course, to (A2) greatly broadens the tuning for the diameter or number of teeth, then insulated from one another and from the use where there is not much local inter- the shafts will turn through different rotor. The rotor connection (-A) goes ference. In this way we can control the angles when the knob is turned and the to the (-A) line and ground while the tuning values to suit local conditions. set cannot be tuned in. stator sections connect with the grids of A two circuit coil, consisting of an An improvement on the first gear two tubes at (G1) and (G2). If three independent primary and secondary, is arrangement is shown in Fig. 3 where the tubes are to be controlled, then a second outlined in Fig. 7. This coil is used as a RADIO AGE for October, 1925 The Magazine of the Hour 37 radio frequency transformer as at (L2) tion and the standard form of wood the "A" battery circuit and must be and (L3) in Fig. 1 and its secondary coil bottom board can be used if desired. In installed as there is no other nathod is tuned by a 0.00035 mf. condenser as the photograph, the audio transformers available for shutting down the detector before. Roughly, the secondary consists are placed out of the way beneath the and two audio tubes. of 160 turns of wire in the secondary and sub -base where they also act as supports Looking at the coils, it will be seen that 40 turns in the primary, but this is sub- for the thin strip of bakelite, and holes the antenna coupler (L1) is of the single ject to slight variations in the method of drilled in the sub -panel allow the trans- circuit type illustrated by Fig. 6 and winding. As with the coupler coil, this former binding posts to pass through for carries the two corresponding antenna is quite a trick to make at home, and it support and electrical connection. taps (Al) and (A2) for sharp and broad will be found much surer and will cost Special attention is called to the gang - tuning respectively. The osts are con- no more in the long run to purchase the condenser at the left and its connection nected to the terminals (CANT--1) and coils ready made. This will eliminate to the two transformers. The transfor- (ANT-2) on the left end of the sub -panel much of the guesswork and the amateur mers are connected to the gang -condenser where the proper antenna connection deals with enough unknown quantities and supported by it through thin metal can be found by experiment. as it is. There are at least three stan- strips bent up to form brackets as well Dotted lines (a-b) drawn to all of the dard makes of these coils now on the as electrical conductors. These three coils represent the metal bracket connec- market and they can be obtained without parts are then assembled in one unit tion made from the (G) post to the stator difficulty from reliable dealers. A sche- before the condenser is attached to the of the variable condensers, these brackets matic diagram of the coil in solenoid front panel, making the wiring a very at once affording a connection and sup- form, is given by Fig. A which is lettered simple matter as all of the wiring connec- port for the coils. The connection from to correspond with Fig. 7. tions are then few and in the open. the (-F) post on the coils to the grounded Both the coupler and transformer are Diagram condenser rotor is made by a strand of provided with a metal bracket (b) which Circuit rubber covered flexible wire in all cases. at one time supports the coil from the A pictorial wiring diagram of the re- This completes the connections made to condenser and makes a connection ceiver is shown by Fig. 9. This circuit the 0.00035 mf. variable condensers, and between the (G) end of the secondary is a simple, five -tube radio-frequency lay- it should be noted that the stator posts coil and the stator plates of a low -loss out without an attempt at regeneration, are marked (s) and the rotor posts of the condenser. reflexing or other diversion from standard condensers are marked (r) to prevent When used as a transformer, the plate confusion when other makes of conden- of the preceeding tube is connected to sers are installed. There is a different the coil post (P), the coil post (G) con- in the method of bringing out the con- nects with the grid of the following tube, denser connection posts in different makes the post (B) connects to the positive THE RADIO AGE of condensers and this is likely to lead to "B" ( +B) 45 volt battery line, and post confusion if not watched carefully. (F) connects with (-A) and ground. A 0.00025 mf. grid condenser (GC) and ANNUAL a 2 megohm leak (GL) will be found most Completely Assembled Set for 1925 suitable for the detector tube. The fixed THE completely assembled five -tube condensers used as radio frequency by- radio frequency set is a very com- passes, and marked (Kl, K2, K3, etc.) arrangement adapted to a 7' x 18' are clearly marked with their capacities panel, and an examination Fill show is Still the Most and call for no comment except for the that hardly a cubic inch of space is wasted, 0.005 mf. fixed condenser (K1) used as yet the parts are easily accessible for a bypass for the potentiometer. It should wiring and for adjustment. In spite of Authoritative and Up -to- be noted that (K1) is connected at one the close packing of the parts into the end to the center post of the potenti- limited space there is no trouble with Date Hookup Book ometer (PO), and at the other end to the feed -backs or other interchanges of en- (-A) line, when a wire wound potenti- ergy between the inductances. ometer is used. With the carbon pilet ype, A conventional straight radio frequency You Can Buy or pencil mark type of potentiometer this circuit is employed in the receiver shown, bypass condenser can be eliminated as the excellent results obtained being deter- such potentiometers have little or no mined by the materials rather than upon Get Your Copy Now inductance and therefore do not affect any trick in the circuit itself, but of course the tuning when the potentiometer knob any other circuit can be used that calls is turned. for the same equipment given in these For the clearest and most satisfactory specifications. There are two radio $1.00 Each! reception, the audio frequency transfor- frequency stages, detector, and two audio mers (AFT-1) and (AFT-2) should have frequency stages which give a high de- a ratio of 3.5 -to -1 or 4 -to-1. Higher gree of selectivity and good distance on ratios may give a somewhat greater the loud speaker. When desired, the practice, the high efficiency of the coils amplification and volume but they may reflex principle can be employed with the making it unnecessary to use other than also cause noise and distortion. equivalent of four stages of radio fre- a standard circuit. A potentiometer Wiring Notes quency and two stages of audio ampli- (PO) used for controlling the grid fication, but in view of the performance potential of the first radio frequency Wiring will be much simplified by the with the radio frequency circuit this is tube is the only control outside of the use of small rubber covered flexible wire not necessary nor even desirable. wavelength controls affected by the instead of the more usual square bus- One single variable condenser (0.00035 three variable condensers, and the wire. Not so much care is necessary in mf.) is used to tune the antenna coupler, potentiometer is used to clarify reception arranging the runs of the wire to avoid while a two -gang condenser shown at the and to vary the volume rather than to short circuits, the difficulties of soldering left tunes both radio frequency trans- control free oscillations. in close corners is done away with, and former by a connection across the coil To simplify the filament controls, a the apparatus can be arranged to a better secondaries as indicated in Fig. 1. By somewhat novel arrangement of the advantage if it is not limited by considera- this means we have only two wave- control resistances has been adopted. tions"of wiring. The distance between the length tuning controls for the five tubes, Only one rheostat (Rl) is installed and binding posts is measured, allowing a a control system that is simple to under- that rheostat controls the radio -frequency little slack in the rubber cover flexible stand and handle and yet is not excessive- tube current. The filament current for wire, and then after cutting to length, the ly sharp nor critical. A single dial con- the detector tube (DET) and the two ends are skinned and connection lugs or trol with a three-gang condenser is so audio frequency amplifying tubes marked eyelets are soldered to the ends of the long that it interferes seriously with the (AUD -1) and (AUD -2) are controlled wire. As this soldering can be done on layout scheme determined upon for the automatically by three (R2- R3-R4) the bench or table, and afterwards con- sockets, and is not so easy to handle as Amperites and therefore need no atten- nected in place, it is an exceeding con- the circuit arrangement finally adopted. tion while tuning -in. It has been found venient method. All five tube sockets are mounted in a by experiment that the detector tube is Assembly Drawing row on a strip of bakelike that serves as not in the least critical to rheostatic a sub -panel and the sub -panel in turn is control in this circuit and therefor can Fig. 10 is a plan view of the assembled connected by metal end brackets to the be controlled by a fixed resistance (R2) as parts drawn to scale. It will be of serv- front panel so that no wood sub -base is well as by the detector rheostat com- ice in laying, oat the work although the necessary. However, it is not absolutely monly used in other circuits. The bat- exact dimensions may vary from those necessary to follow this exact construc- tery cutout switch (SW) opens and closes (Turn to page 40)

-\ íí%nEMI _ 'III IME111111IIIIIII'.

\, WÚJD/'''c.- - ó.q ,1= '= h_,: ; :., _ ..,,., ; ._ 40 RADIO AGE for October, 1925 The Magazine of the Hour (Continued from page 37) Clay '.resin, pioneer in radio industrial WJAZ will be opened and then the shown on the drawing owing to the promotion, advertising and general pub- familiar call: "This is 9 XN calling differences in the various makes of ap- licity, has been appointed associate direc- WNP" will again be heard until the re- paratus. The circuit shown is assembled tor of the Radio World's Fair, succeed- turn of the MacMillan Expedition. on a 7° x 18° standard panel and re- ing the late James F. Kerr, who died (9 XN is the experimental call letters of quires a cabinet at least 814 inches in last June. Announcement of this import- WJAZ Station and WNP is Wireless depth. To avoid confusion, no wiring is ant news to the radio trade and to North Pole, the Zenith station on board shown on this layout -simply the appa- broadcast Iisteners was made this week Commander MacMillan's private Arctic ratus, panels and supports. by U. J. Herrmann, managing director, schooner "Bowdoin" now on her third At points where metal brackets are who has just returned from the Far expedition into the Arctic.) used for the support and connection of North and the MacMillan Expedition The MacMillan programs are sent at the coils, these brackets are marked (b) to expedite the elaborate preparations midnight central standard time and are so that they can be distinguished from that are being made to make the Second usually of an hour or an hour and a half the apparatus. The brackets can be Radio World's Fair a record breaker in duration, consisting of several numbers of made easily from No. 24 to No. 26 gauge the number of exhibits and in attend - music given by friends who have volun- sheet brass, the strips being from 3/4 and as well as for special features of teered for this personal service to Com- inch to 34 inch wide according to the public interest. mander MacMillan, then a short address apparatus used. In any case, the brack- The First Radio World's Fair was so by some close friend of Commander ets must be heavy and stiff enough to large that it required Madison Square MacMillan who has usually come from afford a firm support that will not Garden and the Sixty -ninth Regiment a distance to speak to the Commander, vibrate when the set is being handled. Armory to house it; the second, scheduled and the rest of the time is given over to Compensating Condensers for September 14th to 19th, 1925, will the reading by the Reverend Gardner facilities of largest hall The purpose of the very small corn - require the the MacWhorter of personal messages from pensating condensers used for balanc- in the world, the 258th Field Artillery relatives of the men in the Arctic expedi- Armory, five times as large as Madison tion's personnel, a comprehensive news ing the stators of the gang -condensers this is signi- has already been described, and one Square Garden. In itself, a digest of the world's events of greatest ficant manifestation of the tremendous interest to the explorers, and an occasion- of the condensers is shown at (VI) in of radio. al humorous Figs. 9, 10. Usually a small neutralizing development incident that may provoke a condenser is sufficient for this purpose or Mr. Irwin has been a familiar figure at little laughter in the cabin of the "Bow- radio expositions throughout the country doin" or the S. S. "Peary," the sister ship one of the "Midget" variable condensers of the indus- of having a maximum capacity of about and is known to the leaders the "Bowdoin," under command of try, not only from a merchandising stand- Lieut. Comm. Eugene F. McDonald, ,jr. 0.000045 mf. If either of these conden- He has been sers is not available, then a home made point but as a writer. an During the past two months many dis- enthusiastic ':fan" since radio broad- tinguished guests have taken part in the condenser can be made by using two started. MacMillan strips of brass with a sheet of mica casting programs from Chicago, in- Mr. Irwin started the radio section of cluding: Dean Paul Nixon of Bowdoin between them. Eagle in April, 1924, College, This homemade condenser is of the the Brooklyn Maine, Commander MacMil- as illustrated by Fig. 10A. became manager of the entire radio lan's Alma Mater; U. J. Herrmann, pro- "book" type department in September, 1924, and prietor of the Cort 'Theatre, Chicago, The brass strips (pq) are approximately special inch wide and 1M inch long, and are started broadcasting through a manager of the New York and Chicago studio in the Eagle Building shortly "Radio World's Fairs:" Mr. and Mrs. fastened firmly to the sub -panel at one in connection with Station Frederick H. end with the strip of mica between them. thereafter Rawson of Chicago, parents \VAHG. These programs became well of Kenneth Rawson, fourteen year old The upper brass strip (p) overhangs the known the United States Cabin -boy rest of the assembly so as to carry the throughout of the "Bowdoin "; Mr. and screw (m) by which the capa- and Canada. He resigned to become Mrs. Elliott Jenkins, (Mrs. Jenkins adjusting special representative of the Conde being the former Alexandra Carlisle city can be adjusted. The upper strip Publishing Company in the who given a curvature before assembly Nast placed Calvin Coolidge in nomina- (p) is establishment of a radio department in tion for the Presidency of the United so that it normally tends to stand away end of business. other strip (p). By turning the advertising their States at the Republican National Con- from the In such capacity he participated in many vention in Chicago in 1920); S. I. Marks, down the adjusting screw (m), the capa- conferences to upbuild treasurer city can be increased gradually until the merchandising of the Zenith Radio Corpora- of equal capacity. the new giant industry of radio. tion; H. H. Roemer also of the Zenith two stator units are Radio Corporation; Jack Gregson, presi- dent of the Chicago Bowdoin College Radio Advances Cause of a Broadcasting to MacMillan alumni; F. W. Thurnau, J. W. Cook, and Universal Language from Chicago H. F. Juckett, officers of the Theta Delta Chi fraternity, \V YORK- Educators should be Every Wednesday at midnight an of which Comm. NEvitally concerned -and probably are unusual radio program has been broad- MacMillan is a member. giving the matter intensive study-in the cast from Station \VGN on the Drake announcements of super-power broad- Hotel, Chicago, to the MacMillan Arctic The Wise.Old Man casting stations that are in contempla- Expedition. The programs began on (Continued from page 20) tion and some actually under way at the the day that Lt. Comm. MacMillan He jumped to his feet and rubbed his 50 kilowatt rating, in the opinion of sailed from Boston, June 17, Bunker Hill hand across his eyes. His pipe U. J. Herrmann, managing director of Day, and will be continued until the wasonthe the Radio World's Fair. An Internation- return of his Arctic Exploring Expedi- floor and the rain was pouring in the open al language is likely to become a neces- tion late in September. Commander window and the lightning was flashing. sity within a very few years, Mr. Herr- MacMillan made special request before He Iooked towards his friend but he had mann believes, when transoceanic trans- sailing for the Arctic that his old friend disappeared as mysteriously as he had mission of musical and oratorical pro- and college fraternity brother, the Rever- appeared and gazing at the clock on grams will be regular features to delight end Gardner MacWhorter of Chicago, the table it told Billie that it was four people of many nations. should again render the service of week- o'clock in the morning. He had been "A determination of what this inter- ly communication from home that he national language will be must now be gave during the MacMillan Expedition asleep four hours and the thunderstorm arrived at," contends Mr. Herrmann. of 1923 -24 from the Zenith -Edgewater was now a reality. "Realizing this, advocates of ILO and Beach station WJAZ. Esperanto are debating the question The new Zenith broadcasting station more emphatically than ever. Of course, WJAZ located at Mount Prospect, Illi- John B. Rathbun English now encircles the globe, as the nois, some twenty odd miles out of language of trade and increasing use in Chicago, with the handsome Spanish and His diplomacy, and there are strong reasons renaissance studio on the twenty -third Famous why it should be adopted as the universal floor of the new Straus Building, at tongue." Michigan and Jackson Boulevards, RADIO AGE This universal language situation will Chicago, was not completed in time to BLUEPRINT SECTION be discussed in the forum that will be a carry on this unique broadcasting feature, feature of the Radio World's Fair, during and \WGN was placed at the disposal of Can Be Found the week of September 14th -19th, when the Reverend Gardner Dlac \Whorter in this Magazine leading educators will be guests of the during June and July in order that the management, along with students from a weekly midnight programs might be Every Month hundred schools and colleges. given. At an early date the new station RADIO AGE for October, 1925 The Magazine of the Hour 4 i

Tuned Radio Frequency Kit . NOW-All the world pI -f R4 . . $12.00 Complete with have it! Brackets The sensational favor which Chicago and New York showered upon the AERO COIL has prompted its designers to make it available to every fan in the Nation. Vigorous plans are, therefore, under way to place the Aero Coil where every city and village can see it and witness its markedly superior performance. (tr.

The complete Low Loss Inductance System, comprising two tuned circuit transformers and an antennae coupler with a uniquely constructed Catalan l'opular Rad,. variable primary for governing the selectivity of the antennae circuit. Declared by Chicago and New York the most SELECTIVE, most POWERFUL Inductance Ever Designed! Enjoy the "knife -edge" selectivity with which Aero Coils cut Use AERO COILS through the tangled mass of Chicago and New York broad- Wherever An Inductance Is Required casting at will! Enjoy the uncanny sensitivity with which r THE ONLY AIR DIELECTRIC COILS HAVING sets built of Aero Coils pick up the far off, small, low- wattage ' VARIABLE PRIMARIES IN ANTENNAE stations that you never thought existed! Be thrilled by the IL CIRCUITS amazing volume with which Aero Coils amplify for the loud The Aero Coil 3-Circuit Tuner speaker, reception which you have always had on Another adapta- to listen to tion of the pat- the head phones! Build a 5 -Tube Tuned Radio Frequency Set ented protected Aare. Cod ronstrue- with Aero Coils the true low loss inductance system. tion and for that reason the most efficient three -cir- PATENTS PROTECT ITS SUPER - EFFICIENCY cuit tuner ever of- Its lower circuit resist- fered. More than Build Your Set Now! covers the broad- ance, its lower high fre- 95,E ,-NoAir dielectric cast wave band quency resistance, its dope on The construction which when shunted with lower windings .- All turns makcs possible the far su- o good .0005 con- distributed capac- air- spaced. -Solon oid denser. This is the ity, and the fact that its (cylindrical)windings perior results obtained tuner which in a 3 -tube set broualtt in Hnvann, dielectric is 95% air are Variable primary from Aero Coils also makes Cuba, in the day -time in Chicago. Price $11.00 Engineers recog- the reasons why the Aero nize cylindrical them cost a bit more - Coil tunes so sharply into winding to be su- but, performance consid- The Aero Coil Radio Frequency resonance -and why it perior to any other. ercd, their price is low. Regenerative Kit actually uses the energy The Acre Coil is $12.00 for a sct of three, Consists of one the only Air dielec- AERO COIL 3- which other types of in- tric cylindrical in- complete with nickel Circuit Tuner and ductances waste. Hence, ductance with a plated mounting brackets one AERO COIL Aero Coil is induct- variable primary. which fit Antennae Coupling the Acro Coil patents any condenser. Transformer. ance of today -and to- prevent imitation. Go to your dealer's today Makes the most morrow, and you can be and obtain a set of three. powerful. most se- lective 4 -tube, non assured that it is-for the A circular containing com- radiating art pos construction which makes it the ideal plete hookups for building the most Bible to build. inductance is patented, and no induc- selective, most sensitive, most pow - Price $15. tance can be made so good as Aero Coil crful five -rube receivers ever designed unless in violation of these patents! is enclosed in each package. The Aero Coil Wave Trap Unit for If your dealer has not yet obtained his stock of Aero Coils, order direct, Also Crystal Sets enclosing price with your order. Hy reason of the characteristics made Free Booklet showing new circuits and giving full constructional informa- possible by the Arto Coil construc- tion of help to any fan or set builder -mailed on request. tion, this unit makes a very efficient Write jot the Aero Booklet. wave trap or crystal set. Price $4.00 AERO PRODUCTS, Inc. The Aero Coil Oscillator for Super Heterodynes 217 North Desplaines Street, Chicago, Illinois The characteristics Successors to achieved through HENNINGER RADIO MPG. CO. the use of the Arm Coi, principie make of this instrument the ready mean. to tremendously in. prase an- efficiency of the oscillator circuit in any Su- i per Heterodyne All Aero Colls embrace a patentprotected method Mconatructton which makes possible a far more efftdent receiver. Pr. Se.S0 Inductance performance than is possible with any other type of coil. L P.ruacA br 111H11.41,11-ENGEL AuvaaT/atMi eon rANY. GatcAUQ * Tutsi stai Approssi b>/ RADIO AGB iG 42 RADIO AGE for October, 1925 The Magazine of the Hour Will Call Conference testing its new 50 KW set. Other sta- Hoover tions are preparing to try out broad- Professional Set Builders This Fall casting with 5KW or more. It is esti- Organize of Commerce Hoover will mated that at least twenty B stations Secretary are equipped to go to 5KW, although Custom -built receivers are to be pro- call a national radio conference here only eight have been licensed to do so at moted on an extensive scale if plans of this fall, he announced on his return to this writing. the newly organized Professional Radio Washington last month. Although he Whether or not the recent increase in Set Builders Association are carried has not had time to set a date or draw power will continue to spread over the through. This organization elected offi- up a program, he feels that a conference country is not known; neither is it cers on July 24th, at its first meeting is necessary once a year and believes definitely known how far apart very held in the offices of the Allen D. Card- the three already held have benefited high -powered stations must be located well Mfg. Corp'n, in Brooklyn. in its work. They have the department to prevent undue interference, or how Despite the dullness of the Summer also demonstrated the willingness of the great a separation there must be between season, unusual fans, manufacturers, broadcasters, ama- the wave lengths they employ. interest was displayed teurs and other interests to cooperate If a large number of the present sta- in getting the new body under way. in keeping the air as clear and clean as tions went to high power, regardless of Plans involve newspaper advertising, a possible. their proximity to each other or the testing laboratory, publicity bureau, and The conference will be called in October relationship of their broadcasting chan- a general organization to benefit the or November, it is now believed, partly nels, there would probably be difficulty dealers and professional men who build because of the many other problems con- in separating them. It may be found sets to order, some of the members sell as fronting the Commerce head, and in desirable to locate the very high -powered many as a thousand sets a season, others order to give the Department Radio stations in distant states or perhaps a only a few. Officials and the representatives of the hundred or two miles apart, assigning industry time to draw up plans and sug- them wave lengths separated by fifty The association particularly is endeav- gestions to be considered by the general meters or more. This would of course oring to counteract the tendency of the conference. tend to limit the number of such stations, non -technical public to buy inferior Officials of the Department believe but this will probably adjust itself. apparatus offered at prices inconsistent one of the most interesting questions to There will not be many operators rich with good design and service. It hopes be discussed will be the limitation of enough to build and maintain 50 KW to educate the public to accept radio sets power, or perhaps the removal of the stations, which cost almost a half mil- which afford more service though costing power limitations now in force, if public lion dollars to install. more initially. sentiment backed by experiments now Nevertheless, the views of the public Officers of the association have been going on indicate that there is no reason will be sought, as well as those of the elected with headquarters at 71 -73 West for limiting the power of broadcasting broadcasters, before any definite or Broadway, New York City. A member- stations. limiting action on power is taken by the ship committee was appointed to run Forty -two broadcasting stations are Department. It may be necessary to up the list of active supporters and to now using 1,000 or more watts; seven have the old radio regulations and even start organizing local chapters of the of them are operating with at least the laws amended, and it is understood association in cities all over the United 5KW, a once dreaded figure, although no that the Department will probably States. It is planned eventually to serious complaints have been received have a tentative radio law in shape for standardize the conditions of member- since these broadcasters went on the air. discussion by the time the conference ship so that the public are guaranteed Two stations are now experimenting convenes. service and satisfaction on any sets with, or about to try, 50 KW. WGY's Secretary Hoover is a great believer in turned out by members of the association. tests seem to have been satisfactory, radio as a public service and he is also A number of manufacturers of high and it is said that WJZ, the Radio Cor- disposed to let the public in on any hear- grade radio apparatus have endorsed poration's new high -power project located ing which will affect such a public service the ideals of the association and are con- outside of New York, will soon start -hence the Fall conference is a certainty. tributing to its support.

End your Radio Troubles for 30c in Stamps We have laid aside a limited number of back issues of RADIO AGE for your use. Below are listed hookups to be found in these volumes. Select the ones you want and enclose 30c in stamps for each desired. The supply is limited, so enrich your store of radio knowledge by laying in an ample stock of copies NOWT

January, 1924 September, 1924 April, 1925 -Tuning Out Interference -Wave Trope- Eliminators -How careful Mounting Will Improve Reception. -A 3-Tube Portable Set. -One Tuning Control for Hair. Breadth Selectivity. -.S.' Voltage from the A. C. Socket. -- A Junior Super-Heterodyne. -Four Pages of Real Blueprints of a New Baby Heterodyne -An Amplifier for th 3- Circuit Tuner. -Pooh -Pull Amplifier. and an Aperiodio Variom.ter Set. -Blueprint. of a Five -Tube Radio Frequency Receiver. -Roeenbloom Circuit. -Data Sheets. October, 1924 May. 1925. March. 1924 -An Easily Made Super-Het. -A "Quiet" Regenerotar. -An Eight -Tube Super -Heterodyne. -Two Radio and Two Audio for Clear Tone. -A Power Supply Receiver. -A simple, low loss tuner. -A Simple Regenerative Set. -How to Make a Tube -Tester. -A Tuned Radio Frequency Ap)iSer. -The Ultradyne for Real DX. -A Unique Super -Het and an Improved Reinarta. -Simple Reflex Set. -Real Blueprints of a 3-Tube Neutrodyne and a Midget -A Sts Tube Portable Receiver Illustrated with Blueprints RaSex Set. Apra, 1924 November, June, 1925. Efficient Super -Heterodyne (fully illustrated) 1924 -Reducing Static Disturbances -A. -Blueprints of a Single Tube Loop Set and a Capacity Feed- _ -A Ten Dollar Receiver. -A Seven -Tube Super -Heterodyne. -Anti-Body Capacity Hookups. back Receiver. Seta. -A 3 -Tube Low Regenerator. the Thre,C rcuit Tuner. 7 r wo ning Receiver. -Reaming -Mastering the 3- Circuit B- -Drake verOrilioery -loden and first two ioetofinents of Radio Age Data Sheet.. Tuner. -Overcoming- Oacillatiom in the Roberte Receiver. December, 1924 in Practical Form. -Blueprints of a New 8-Tube Super-Heterodyne. -An Ideal Set May, 1924. -Soldering Secrete. -Construction of a Simple Portable Set. -How to Make a Receiver that Minimises Static. -Radio Panels. -A Trans -Atlantic DX Receiver. July. 1925 -Third Installment of Radio Age Data Sheets. -How to Make a Home Made Battery Charger and a Loud -Learning Tube Characteristics. Speaker at a Small Cost -How Much Couplme? June, 1924 January. 1925 -The Six -Tube Super -Autodyne. -Important s Super -Heterodyne. -A Refleaed Neutrodyoe. -A Simplified Portable Super-Het -A Duivant actor in Constructing -A Six Tube Super-Het. -Blueprints of Conventional Radio. -A Sure Fire Reflex Set. -An Efficient Portable Set. -Symbols and Crystal Detector Circuit. -Adding Radio and Audio to Baby Heterodyne. -A Tuned Plate Regenerator -Radio Age Data Sheets. -Makivg a Station- Finder. August. 1925-SOe per copy February. 1925. -How to Attain Smooth Tuning. July. 1924 Sure Shot -Het. Current Tubas. -A Portable Toned Impedance Reflex. -A Super -Alternating Bias. -A Three Circuit Regenerator. -Deciding on a Portable Super - -Operating Detector Tube by Grid blueprint section. in which ie tained -Tube Wizard Circuit. -A Real. Low Loss Set. -And a big 60-page -A Three -Blueprints of a 3-tube Reflex. blueprints of oil the beak circuits from whichc a l radio -Data Sheets. March, 1925. hookups bave been developed rince the birth of Radio. Permanent Sup-Het. August. 1924 -A September, 1925. -Breaking Into Radio Without s Diagram. -A 5-Tube R. F. Receiver. 4-Element Tube. -How to Wind Low Loss Coale. -Thirty-one ways to prevent self-oscillation.. -The English -Tuning efficiency with two control. -Faltered Heterodyne Audio Stages. -A Short Wave Receiver. Circuits. -An Audio Amplifier Without an "A" Battery. -Blueprints of a Two-Tube Ultra Audlon and a Regenerative -Ideal Audio Amplifier -Data Sheets. Reflex. -Blueprint section. RADIO AGE, INC., 500 N. DEARBORN ST., CHICAGO RADIO AGE for October, 1925 The Magazine of the Hour 43

Nk.}y: 3\. -$44", N, 41. "4,1 Pick UPS -1- . .. n A--- i 4 _ ,_. n®okups 46, ---r 1 eaxders material appearing under the title "Pickups and Hookups by Our Readers" in RADIO AGE, is THEcontributed by our readers. It is a department wberein 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 berein 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. Conducted by Fred Hill REPRESENTING southern recep- CONTRIBUTORS tion, Robert Barbee, 6114 Caddo Ave., Cedar Grove, La., submits Name Address City a list of stations picked up on a factory Walton Van Winkle, Jr 2528 Benvenue Ave. Berkeley, Calif. built set, the list ranging from the East Arol Schmidt 484 40th St Milwaukee, Wis. to the West coast. DIAL TWISTERS Interesting daylight reception is re- Albert W. Small 1210 12th St., N. W..___ Washington, D. C. ported by Robert C. Potter, R. R. 3, Robert Barbee. 6114 Caddo Ave Cedar Grove, La. Beamsville, Ont., Canada, who is already Vialis F. Walz Glen Haven, Wis. a member of the Dial Twisters. He has Chas. W. Justus_.__.. 2072 Greenwood Ave Toledo, Ohio picked up 47 stations in all on a crystal George Wistow._ 95 Leslie St Toronto, Ont. Can. set. His daylight list includes several J. P. Morrison, Jr 1711 South Peoria Tulsa, Okla. Canadians and WBZ, WGY, KDKA, Joseph H. Miller__ 217 Pearl St..__ Brooklyn, N. Y. WEAR, WTAM and WMAK, all of Winston Klontz._ Mt. Morris, Ill. which makes an excellent record for C. C. Schlegel Kenesaw, Nebr. some of our crystal gazers in the States J. D. Johnston U. S. S. Denver.___ New York, N. Y. to attempt to beat. Bertram Susdorf Rantoul, Ill. John W. Wilson, Jr 1764 Gilpin St..__ Denver, Colo. Willis Stratton... R. F. D. Route 1_ H. Predosa, 2864 Lincoln Ave., Chi- Canandaigau, N. Y. 113 Scoville Way cago, Ill., writes as follows: "Received J. M. Landon._._ N. S. Pittsburgh, Pa. Harold Huffman. Box 4, Van Dyke P. O. Van Dyke, Mich. your answer in regard to the three tube and want to congratulate Chas. E. Ross_ Elgin State Hosp Elgin, Ill. neutrodyne Fred C. Favre Cressville, N. on your promptness. The reason J. you George Tucker.__ 1257 Benitean Ave Detroit, Mich. for is one time I wrote this that to the Angeles St.____ Magazine for a little informa- Ramon Quesada 36 Havana, Cuba V. Alcock Lynton Green Lanes, Pal- had to wait two months for a tion and mers Green- London, Eng. reply, and the nature of the question John Skewis 1731 Beaufalt Ave. Detroit, Mich. was similar to the one I wrote you." or less Okey Deem 1716 East 7th St.. Parkersburg, W. Va. All of which more confirms our G. M. Hewson. Drawer 705__ Drumheller, Alta., Can. opinion that when a fan writes in, he Elmer H. Glafke 202 Rumely St LaPorte, Ind. desires an answer. The staff has made F. McGarr Binghamton, N. Y. it a point to answer all questions just Ray Masterson 744 Greene St Marietta, Ohio as quickly as it is possible to do so. T. C. J. Dixon. 1913 Decatur St_ Houston, Tex. Willie R. Jones.. 1249 Wood St Shreveport, La. Mrs. Frank A. Duston. Box 424 - __- _._...... _.._ St. Stephen N. B., Can. Our genial English informant, R. A. G. V. Skal.... Ober Schreiberhau. Rsgb., Germany Ganatt, 17 Lorne Road, Stroud Green R. F. Cochrane 1303 Main St Moncton, N. B., Can. N. 4, England, who furnished us with a Elmer Hopper Paris, Tex. bit of gossip from his side of the Atlantic in the August issue, gives us some more data of interest to our radio fans who paying audience who use special adapters Los Angeles, Calif., tells us: "I have have a flair for radio's international for the broadcast. It is expected that read your RADIO AGE for July from scope: theater broadcasts will be furnished cover to cover and get more real radio British tubes at last are being made of the company. (It may work news than from any magazine for four patrons a long with the standard prong base over there, but where's the kick in having time; and I read most of the magazines. similar to the type to which the Ameri- your stuff piped nto the house like gas In regard to the best type of set, I be- can listeners are accustomed. or water? Eh wot?) lieve if I lived in a big city a regenerative Glass panels instead of bakelite are Ganatt says in the majority of cases set would do for me; if in the country the thing France and Britain. now in where two way communication between a 5 tube r. f. set and if real far away a (Oh, the weary hours of drilling!) England and America has been ac- super- het." The DX list accompanying Croydon Aerodrome, near London, complished by amateurs, such work has the letter entitles Mr. Chandler to the call GED, uses a wavelength of 900 been done by the English amateurs DT emblem. meters. (Not much chance for the living in suburban districts and not in log him, >t Americans to on account of the cities like London and Manchester, where B. Odell, 270 Odgen St., Orange, N. J., limits of most sets being 550 upper there is the worst shielding imaginable. says he is quite pleased with the 8 tube meters. However, there is some chance (Same of our friends in England should super he built from the description by for the dyed-in- the -wool experimenters try Chicago's Loop district for trans- Calcaterra in the May number of RADIO with separate coils for the different bands. mission. It's like transmitting under- AGE. "Secret Wireless, Ltd.," is the name ground.) of a newly organized company in Eng- O. L. Overton, Station G, Memphis, land contemplating broadcasting to a J. Robert Chandler, Arcade Box 1004, Tenn., senda in his idea of a "go- getter" 44 RADIO AGE for October, 1925 The Magazine of the Hour

Joseph H. Miller, 217 Pearl St., Brook- lyn, N. Y., working through local inter- ference, has a commendable list showing a great deal of perseverance. The cir- cuit is a three circuit type with only one tube. Before the single tuber came into being, Mr. Miller was a confirmed crystal fan. In addition to the broad- casting stations, a number of "hams" are included in the list. Using a single tuber, Winston Klontz, Mt. Morris, Ill., furnishes a worthy list of radio reception, taking in the two coasts and Canada. C. G. Schlegel, of Kenesaw, Neb., asks us to give some of the superdyne circuits, believing that our August num- ber catered principally to the newly initiated instead of the dyed -in- the -wool experimenter. The circuit to which he refers is not so much a circuit as it is a trade name.

Writing from the U. S. S. Denver, care Postmaster, New York, N. Y., J. D. Johnston relates his experiences with radio, beginning with a crystal set and thence via the usual route to a three tube regenerative, a five tube neutro- dyne and finally the super -het, using the modulation principle instead of the Fig. I.The picture above shows Herbert Hiley, of theBritish station G21 H, situated at Keigh- conventional double detection. ley, Yorkshire, who has been successful in establishing communication with M. Fresni, Rua Aswaldo Cruz, Nieteroky, Brazil, a distance of 5400 miles with a wavelength of Attesting the popularity 42 meters and 15 watts in the antenna, the circuit used being a Hartley loose coupled. of the one Mr. Hiley is shown logging a station. The photograph is by courtesy of G. Crowther, tube regenerative, we have John W. 28 Cask Road, Keighley, England. Wilson, Jr., of 1764 Gilpin St., Denver, Col., sending in his application for the set which is a variant of the well known feel that way, too. Let's see what they DT honors. We often wonder if the Weagant, single circuited. He reports have to say. possessor of a five tube set or even a excellent results with it, as many other super ever really gets the thrill out of the fans have. George Wistow, 95 Leslie St., Toronto, game that he "did when he first listened Ont., Canada, must have an adding on a pair of "cans" to a weakling signal Vialis F. Walz, Glen Haven, Wis., machine running hot, for he reports from a distant broadcaster. found the ultra -audion circuit in our hearing 265 stations within a span of "Radio Rodeo" in August and has been eight nights, the list showing an average Being anxious to hear what is trans- having great luck with it. The panel of something like thirty stations a night. piring on the lower wave bands, Bertrand was three ply board; it was hooked up Susdorf, of Rantoul, Ill., rigged up a with bell wire and no soldering done. For the benefit of our transmitting short waver and picks up KDKA, WGY After getting a nifty bunch of stations, fans and our general readers, we are and an occasional other station in the Mr. Walz intends making the set over running in this section a picture of the region below 100 meters. In addition in permanent form for use in chasing station of Herbert Hiley, British G21H, he has a three circuit set used for the DX stations. The ability of the ultra - located at Keighley, Yorkshire, who has standard broadcast band. audion to transmit signals with a micro- been successful in establishing com- phone in the ground lead depends en- munication with M. Fresni, Rua Aswaldo Over two hundred American broad- tirely upon the antenna, ground and the Cruz, Nieteroky, Brazil. The distance casters, three hundred some odd ama- amount of power which the tube will in this case was 5400 miles. The wave teurs in the U. S. and fifty or more handle. Of course, to do any trans- used was 42 meters and the power, 15 abroad, to say nothing of 2EH Scotland, mitting it will be necessary to have a watts, output. The circuit used was a SNO, Newcastle, Eng., YL, Paris, France, transmitting license from the U. S. De- Hartley loose -coupled. 4AG, Dunedin, New Zealand and CB8, partment of Commerce. Application Buenos Aires, Willis Stratton, R. F. D. for such may be made to Mr. E. A. Using a regenerative set with trans- Route No. 1, Canadaigua, N. Y., easily Beane, Radio Supervisor, Ninth Radio former and resistance coupled audio qualifies for DX honors and the coveted Disgrict, Federal Bldg., Chicago, Ill. amplification, Walter Van Winkle, Jr., DT button. Fine biz, we say. information is given for Mr. 2528 Benvenue Ave., Berkeley, The above Calif., J. W. Landon, 113 Scoville Way, host of others who have whiles away the hours logging Walz and the the two N. S. Pittsburgh, Pa., on seeing in a written in asking regarding the use of a coasts, despite the presnce of about fifteen recent number William J. Sergeant lead. Pri- locals in the Bay that microphone in the ground counties. The re- was interested in a four tube set that marily the set would be only a very short sistance coupled amplification and the would sharp, furnished Mr. Sergeant -pull arrangement tune range transmitter. push has been touched with the diagram and constants of the upon previously by Mr. Rathbun in September circuit he is using. Just another indica- Charles W. Justus, 2072 Greenwood the blueprints. tion of the wonderful bond of friendship Ave., Toledo, Ohio, remarks that the that exists between members of the same coast to coast set which was published J. P. Morrison, Jr., 1711 South Peoria, fraternity. in the March issue should be included Tulsa, Okla., sends us an excellent list in the blueprint section which this maga- of stations heard during the Summer. We almost fell out of our chair when zine maintains each month. He feels He is a recent convert to RADIO AGE the following letter appeared at the that such good hookups should be shown and thinks ours the best magazine cater- RADIO AGE office: "At last I have in the prints. Maybe some of our readers ing to the broadcast listener. found what I wanted. It is 'RADIO RADIO AGE for October, 1925 The Magazine of the Hour 45 Sontd for this dfi: _ :

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AGE,' the radio magazine with blue- would like to announce that the D. T. the distances are all in excess of a thou- prints, not overstuffed with technical buttons are sent out every month just sand miles. Que tal, amigo? terms and not entirely neglecting the about the time the issue is run off the beginner. I have been a fan for five press. Sometimes there is a little delay RADIO AGE has one Dial Twister years and have been getting most of the incident to a press of business, but as a (he will be when this issue is off the press) radio periodicals. Recently I stopped rule by the time the issue is on the news who receives all kinds of European buying the artists' pictures and out- stands your button should have arrived. stations. Don't all jump at once. He landish histories of radio until now I is a sea -going operator, V. Alcock, am only receiving one, and as soon a George Tucker, 1257 Bevitean Ave., Lynton, Green Lanes, Palmers Green, my subscription expires that magazine Detroit, Mich., with a factory built set London, England, who seems to run will expire with it as far as I am con- logged fourteen stations in a half hour. London to Galveston and return. In cerned. Today was the first time I saw Since seeing the August number, he is addition to all the European stations, he your magazine and I have only had time interested in a super to see if he can better picked up a flock of the American sta- to read one article; but it appeals to his record. tions, quite a few Canadians, Mexicans me so I want to hasten to get on your and a Cuban, all of these on the voyage subscription list. I see the wisdom of Arol Schmidt, 484 40th St., Mil- previously mentioned. Many a D. T. your not naming the firms names or waukee, Wis., favors us with a letter would give his right arm for a chance to any of the parts used in your articles, telling about Mr. Dunwoodie, at Apia, cross the Atlantic with nothing to do but I am so taken with Mr. Rathbun's Samoa, who regularly receives KYW, but log 'em on all sides. article on the 8 tube super that I wish KFKX, and who also has logged to build it. Portland, Ore., and a Canadian station, John Skewis, 1731 Beaufalt Ave., "This one article is worth more than the distance being something on the Detroit, Mich., tells us he built about the yearly subscription cost." order of eight thousand miles. Mr. twenty sets, last winter, and has just This was written by James M. Ben- Schmidt encloses a diagram of the re- finished the set shown on page 23 of the nett, P. O. Box 1431, Weirton, West ceiver used by Mr. Dunwoodie, which is a February Radio Age, which he says beats Virginia, and we'll say it is some letter. two stage radio and a detector, the latter them all. Mr. Skewis is a shut -in and coupled capacitatively from the grid of has plenty of time on his hands. He Harold Huffman, P. O. Box 4, Van the detector to the plate inductance of the says: "It's a pleasure for me to take one Dyke, Mich., favors us with a list of preceding tube. The detector is regenera- of your hookups and construct it, as I stations picked up on a single tube set, tive, a la Armstrong. The antenna coil have full confidence in its being as stated using a split variometer. The list in- is 35 turns, its secondary, 50 turns span- in your magazine." Using the set re- cludes some Canadians. ned by a .0005; the output of the first ferred to on page 23 of the Febru- "Good parts" is the reason assigned by tube goes through a r. f. transformer, un- ary Radio Age, he picked up CNRE, F. C. Favre for his success with home tuned, to the grid of the second tube. Edmonton, Alberta, Canada, about 1500 made radio sets and the number of sta- The plate inductance of the second tube, miles from Detroit, bringing in the sta- tions logged according to a letter received which is also the secondary of the detec- tion on the loud speaker. He now only from him at Cressville, N. J. tor circuit, contains from 40 to 60 turns, awaits the coming of good DX weather bridged by a .0005 mfd condenser. The to get up a DX list that will knock 'em No, Geraldine, there are no battery tickler coil has 75 turns. In Mr. Dun - cold. That's the spirit. solutions that take the place of an elec- woodie's case spiderweb coils are used; tric charge for your battery. A storage any tubes are suitable and only 45 volts Albert W. Small, 1210 Twelfth St., battery is a typical example of the "put is necessary for a B battery. The re- N. \V., Washington, D. C., has fine and take" game. You take out so much turn from the first grid is put on the results with the ultra -audion, using and you must put back so much. Since slider of a 400 ohm potentiometer. A either the resistance coupled or trans- you take current you must replace cur- diagram of the circuit is shown in Figure former coupled audio amplification. rent. You don't take the solution so 2. why should you figure on adding solu- Okey Deem, 1716 East 7th St., tion? A one tube Reinartz, home made, is Parkersburg, West Virginia, will not be all that Ramon Quesada, 36 Angeles St., weaned from the Armstrong single cir- For the benefit of James R. Harts- Havana, Cuba, requires to bring in both cuit regenerative, which brings him all horne, 2258 Bedford Ave., Brooklyn, N. the coasts, Mexico and Canada. The manner of signals, and whose list entitles Y.. and a host of other Dial Twisters, we list of stations logged is not very long but him to one of the buttons.

F, Fig. 2. Many of you have wondered what Mr. Dunwoodie at Apia, Samoa, about 8,000 miles from Chicago, used for reception, Well, the story is shown above. Two stages of radio and regenerative detector. The diagram is self-explanatory. Spiderwebs may be used for the coils, or any other form of good inductance. The set will work with any tubes and only 45 volts B battery is required. RADIO AGE for October, 1925 The Magazine of the Hour 47

!II111//////////////

R. AI I O Sets and Parts

MONTGOMERYi WARD E. CO. Ward's New Radio. Catalogue Is Yours Free

Yours Free -the newest, most in- Ward's is Headquarters teresting book published on Radio. for Radio A book prepared by Radio experts Ward's is today one of the greatest -a complete Radio manual. Radio stdres in the world - selling 52 fully illustrated pages showing everything in Radio without the what is new in Radio and what has usual Radio Profits. And besides, been approved by the best experts. we sell only the tested and approved It shows sets from one tube to equipment -selected and tested by five tubes, the new one dial control, our own experts, who are up to the parts and supplies, batteries and minute in Radio. Thousands of cus- cabinets. It gives a list of stations, tomers write us of their delight and a radio log for recording stations. saving on Ward's Radio sets.

Our 53 year old Policy To Montgomery Ward & Co., Dept. 18-R For 53 years we have sold only quality merchan- Baltimore Chicago Kansas City St. Paul dise under a Golden Rule Policy. You can rely Portland, Ore. Oakland, Calif. Fort Worth of shown absolutely upon the quality everything (Mail coupon to our house nearest you.) in this Radio Catalogue. this Please mail my free copy of Montgomery Ward's New Radio Catalogue. Name Mont A a Ward &Co gomeiy Local address The Oldest Mail Order House is Today the Most Progressive Post office Baltimore Chicago Kansas City St. Paul Portland, Ore. Oakland, Calif. Ft. Worth State * Tested sad Approved by RADIO AGI * 48 RADIO AGE for October, 1925 The Magazine of the Hour i An Organized Warfare Against Fading (Continued from page 22) with primary inserted in the plate circuit of the second detector of a super- hetero- dyne, the proposed rectifying unit can be added either within or outside the receiving set by the arrangement in- dicated in Figure 1 of the circuit diagram. Here it will be noted that the audio - frequency transformer with primary shunted by a condenser to by -pass radio - frequency currents is left in the circuit so that the telephones may be used in an audio stage for monitoring purposes. "Where the wiring of the receiving set is inaccessible, as with the 'Radiola the primary of the extra intermediate - frequency transformer (42 kilocycles) may be inserted by means of an adapter which raises the electron tube so as to allow opening the plate circuit between the socket and the tube itself, as shown in Figure 2 on the diagram. (Adapter THE KODEL MICRO- may be constructed from the base of PHONE LOUD SPEAKER an old UV -199 tube and any adapter is an exact replica of the made for this type of vacuum tube. transmitting microphone used in broadcasting. The second detector of the 'Radiola' The effecment Kodel reproducing is the third tube from the left when unit, with an ingenious new snail.shell horn, mounted inside facing the cabinet.) By employing only the microphone cese, produces the first stage of audio amplification a remarkably clear, full -toned volume. Non -vibrating tone for the monitoring telephones it is distortion. chamber eliminates possible to utilize the vacuum tube of The $15 model incorporates the new Kodel, Jr. unit; with the the second audio stage (at the extreme large Kodel unit. $20 left when facing the set) for the two - Rodmo deetere everywhere have them electrode rectifier by making another THE KODEL RADIO CORP adapter which raises the tube and leaves 506 E. Pearl St.. Cincinnati, O. only the filament connections in cir- cuit. "A voltmeter should be placed across the filaments of all vacuum tubes and voltages should be kept the same through- out all test periods. This applies also to the two- electrode tube, if used. If the same filament battery and the same type of tubes are used for rectifier and receiv- ing set one voltmeter will suffice for all. 'B' batteries should be in condition to insure constant voltage throughout a test period. "Some observers have had difficulty with a serious lag in the response of the gICROP galvanometer pointer. This effect can usually be minimized by critical damp- ing. Probably the easiest way to accom- plish this is to shunt a resistance box .: across the galvanometer while in circuit LOUD SPEAKER and vary the resistance until the pointer responds quickly to current variations. In case a shunt resistance fails, a series resistance may serve the purpose. The former should correct the vibration r .L effect; the latter is needed in case the pointer lags. RA DIO CONSOLE "When recording is done on a con- tinuous tape the exact time should be RAULF MFG. C0.562 VEDDER ST. indicated on the record approximately every 15 minutes as a means of checking CHICAGO. WRITE FOR CIRCULAR for later comparisons. Where readings Largess Selling Transformen in the World are taken and plotted later it will natur- ally be necessary to check the time much more closely as deflections will be read For "Who's Who in Radio" Watch for Radio several times a minute. Changes in receiver amplification made during a Age Every Month. Don't Forget to Re- record should be noted, together with new your Subscription! the approximate ratio of change. * Tested and Approved by RADIO AGE * RADIO AGE for October, 1925 T he Magazine of the Hour 49

Improved Roberts

11 Y

Approved by Ten leading manufacturers

THE new Hammarlund- Roberts receiver is the united achievement of ASSOCIATE ten leading engineers, endorsed by ten of the best -known radio manu- MANUFACTURERS facturers. No one man's or one group's conception of five tube possibili- ties but the composite of the leaders' convictions. All- American Radio Corp. This concentration of the leaders in engineering and manufacturing skill upon one purpose Alden Manufacturing Co the perfection of tried and proven radio principles by new and intense applications produced- N. 17 new results so vital and so valuable that they put the Hammarlund- Roherts far heyond your Radial) Company Xwrv,fi4ddtfa expectations of performance. Carter Radio Company %Ìammánd- In designing this new standard of efficiency, the consulting engineers had at their disposal the Dubilier Condensers finest parts the market affords -regardless of cost. They were not handicapped in huilding RECEIVER. to a price. Union Radio Corp. These ten leading manufacturers offer to the American public greater value than ever International Resistance Co. hefore. A radio receiver constructed throughout of the latest, most efficient parts designs at a price within the means of every one. A five tuhe receiver that equals the Super -Heterodyne Hammarlund Mfg. Co., Inc. in selectivity and volume. A receiver so simple in design that anyone can build it from the instructions in the " Hammarlund- Roherts Construction Book." You will wonder at this new Send for this most com- simplicity; this new efficiency; this new saving. plete book. giving full in- structions on assembling. wiring, and operating the Write for book Hammarlund- Roberts re- this most complete ceiver. 25c HAMMARLUND- ROBERTS 1182 -D- Broadway, N. Y. Na -ald sockets and The Aft- American dials, Carter Rheo- Radio Corp., contrib- stats, Jacks an d L the Ragland Switches approved Lyric Transformer to a-ia m m a r l u n d- for the Hammer - the efficiency of lund- Roberts. this new receiver. ROBERTS *TM it Tested and Approved by RADIO AGE b SO RADIO AGE for October, 1925 The Magazine of the Hour Where Does the Power Come From? (Continued from page 14) phone circuit varies. Naturally, the Test source of potential used must be un- varying, for a fluctuating potential would cause noisy and distorted trans - Your mission. For this reason, generators are never used in microphone circuits because of fluctuations which are neces- Bat- sarily impressed upon the output. Bat- teries of some kind are always employed. teries When faithfulness of reproduction is attained in transmission, the micro- phone has responded accurately to an Get a Jewell air wave form of extraordinary com- No. 84 `B" plexity, with full consideration to over- Battery Volt tones or harmonics, correctly propor- tioned according to the character of the Meter and various instruments. The current supply test your bat- to the microphone supply has been un- teries regu- varying, without tending to increase the energy on some frequencies at the expense larly. You'll of others. Billions of chemical actions save a lot of have contributed to an even and re- radio trouble. sponsive potential supply, so that the finest graduations of sound waves have been translated into current variations. Order from Dealer A. F. Circuits BECAUSE the frequencies involved Send for a Jewel 15 -B Radio Catalog. in the microphone circuit when passed through telephone receivers cause sound waves to which the ear responds, Jewell Electrical Instrument Co. they are termed "audio-frequency" cur- 1650 Walnut St. - Chicago rents. They are identical with those transmitted over telephone lines. In "26 Years Making Good Instruments." receiving sets the audio -frequency am- plifier magnifies such currents. The term "audio- frequency" is used to desig- nate electric currents of less than 10,000 cycles or alternations per second, be- cause such currents can be used to set up sound waves affecting the auditory nerves. A NEW HI -MU TUBE An electric copy of the sound waves The HI-CONSTRON having been produced by the micro- Tube (Price $3.00) phone and its associated equipment, it Model C. T. lolA is next amplified by vacuum tube am- A CLEARTRON PRODUCT plifiers until it is a very powerful audio- For Resistance Coupled Amplifiers frequency current. If broadcasting is The Hi- Constron is a Hi -Mu tube with an amplication constant of 20 that has lines from been especially designed for Resistance Coupled Amplifiers. The Hi- Constron done with the aid of telephone was the first Hi -Mu tube offered for sale to the general public and is the a remote control point, from four to ten result of years of research work. be used. Others may imitate the Hi- Constron as to its appearance but none surpass stages of amplification may its quality. All these amplifiers use batteries in We also manufacture order to assure an absolutely quiet CT 201A CT 199 Standard Base reproduction, free of hums and clicks. CT 199 Small Base CT 400 Rectron for B Battery Eliminators This current is further amplified by the List Price of all types, $2.50 modulator tubes of the transmitter until CLEARTRON VACUUM TUBE COMPANY it is of the same order of magnitude as 28 West 44th St., New York, N. Y. the radio frequency carrier current Factories -West New York, N. J. and Birmingham, England itself. All of this manifold amplification must be carried out without the intro- duction of distortion or extraneous noise if good quality of reproduction is to result. Another process is required, however, before these currents can be radiated into the ether. While audio -frequency currents pass successfully through wire telephone circuits, they do not set up Increase Distance,Volume, Clarity A regular $25 loud speaker for electro- magnetic waves when used to 515. Loud, clear, mellow tone. "Colytt" adjustable grid leak improve. receiving. Gives Bell 13X in. diameter, horn charge an antenna system. The property proper value of leak I. grid circuit. and hold. It. Simple, one hole 22 in. high, equipped with of setting up electro- magnetic waves in compact, easy to install, only Lakeside $100 in panel. Tunes any tube perfectly. Adjustable Unit. is by radio frequency Try the "Colytt" on Agents wanted, write for par- the ether possessed ticulars. Complete Money-back guarantee. currents. In broadcasting, very high 11.00 complete, with full wavelength directions. .sot Lakeside Supply Co. frequencies are used. The of a station is determined by the fre- _R.A.COLYTTLABORATORIES 73 W. Van Baron St., Chicago * S65 Wnhiastaa Blvd.. (Limo (Turn to page 52) * Tested and Approved by RADIO AGE * RADIO AGE for October, 1925 The Magazine of the Hour 51

Spreads the Stations Over the Dial The new AMSCO Allocating Condenser is the triumphant combination of electrical engineering and mechanical ingenuity. Electrically efficient in unscrambling the stations on your dials. Each dial degree from 1 to 100 will be found to represent 10 broadcasting kilocycles accurately over the entire scale - " a station foreveryde- ( gree." Mechanically ingenious in correcting the fault of other S. L.F. Condensers -it conserves space! Scien- tific low -loss construction. Rigidity with light weight. New! abandsome insuu. Made in three capacities -Single or Siamese. Ask your dealer, or ment at a low price, the write for details of the entire AMSCO Line of engineered radio parts. AMSCO Vernier Dial gives finesse to your fingers. Steps - down 13 to 1, backwards or AMSCO PRODUCTS, INC. Dept. P. forwards, without momen- Broome and Lafayette Streets, New York City tum or backslash. * Tested and Approved by RADIO AGE ' 52 RADIO AGE for October, 1925 The Magazine of the Hour Where Does the Power Come TRUE TONE QUALITY From? (Continued from page 50) quency of the currents used to charge or discharge the antenna. Thus, for in- stance, a wavelength of 300 meters is set :á` up by a current of a million frequency DISTORT REPRODUCTION and 492 meters by 610,000 frequency. Various methods for generating these high frequency currents have long been known THE DAVEN to radio art. But how to com- SUPER- bine the radiating properties of radio AMPLIFIER frequency with the audio -frequency com- ponent necessary tb the transmission of speech and music long baffled the scientists who devoted themselves to the problem. The first use of radio frequency currents in communication was for dot and dash telegraphy. By means of the transmitting key, the gen- was erator of high frequency currents is VOLUME formerly the goal of radio engineers. Thé blare of dis- connected and disconnected from the cordant trumpets succeeded the tinkling of the harp. The goal had been antenna system in accordance with the reached. telegraph code. But true tone quality is the star we now are shooting at. This explains the phenomenal growth of the demand for resistance coupled amplification. How It Started The end of the era of distortion is in sight. THE first attempts at radio telephony pioneered in consisted of using a variable resistance Daven engineers have resistance coupled amplification. to vary the amount of radio frequency Daven Resistors and Mountings, Ballasts, Amplifier Kits and Super - current in the antenna, according to the Amplifiers are standard everywhere. sound waves to be sent out. Thus, the The Daven"Super- Amplifier is the aristocrat of amplifiers. Absolutely no carrying qualities of the radio frequency distortion. A revelation to music lovers. It is sold by dealers everywhere, current are utilized, while the distinc- complete, ready to connect with tuner and batteries, for $15.00. tive communication possibilities of speech are retained. DAVEN HIGH -MU TUBES In these early radio telephone trans- MORE volume of true tone quality is the latest achievement of Daven engineers. mitters, microphones were used in series The new Daven Tube Type MU-20 increases the amplification of the Daven Super with the antenna system to accomplish to equal or exceed that obtainable with transformers. 6 volt, y ampere-$4.00 this variation of the radio frequency or each. "carrier" current. But microphones The Daven Power Tube Type MU-6 for the last, or output stage-$5.00 each. are practical only for controlling small DAVEN PRODUCTS ARE ONLY SOLD BY GOOD DEALERS currents. When the radio frequency dis- T!/.e JbegrnF heavy currents necessary for long e' tance transmission are passed through WYgNIAB i gr`CôgfioltAitof * them, they fail to carry the load. SPerirloc Specrálifdr The process of combining radio and Newark (Reg. U. S. Pat. Off.) New Jersey CLIP audio -frequencies is called modulation. THIS COUPON A practical method obviating the neces- 7 sity for heavy microphone currents suit- DAVEN RADIO CORPORATION H -10-25 able for high power transmission was 158-160 Summit SL, Newark, N. J. Please send me the following on Resistance Coupled Amplification: developed by R. A. Heising. It depends Check one for its operation upon varying the plate Resistor Manual. 30c is enclosed. potential of a vacuum tube transmitter Complete Catalog (free). RESITOR MANUAL rather than changing the resistance of The Handbook of Resis- Name the antenna system as radio frequency tance Coupled Amplifi- currents are applied to it. With the Address cation. At best Radio Heising system, the audio -frequency FOR DEALERS: Send your letterhead or card, or this coupon and we will Dealers 25c. Direct by have our nearest distrihutor communicate with you. mail, postpaid 30e. microphone currents are magnified by successive stages of amplification until THE BIG LITTLE THINGS OF RADIO they are of the same order of magnitude as the radio frequency carrier. These amplified microphone currents are used to add or subtract from the plate poten- tial supply of the radio frequency oscil- lator tubes. Thus, the carrying qualities of radio frequency currents are combined with the communication properties of audio -frequency currents to set up electro- magnetic waves in the ether. The work of the receiving set is just SETS, PARTS, KITS the reverse of that of the transmitter. BIG SAVINGS Dealers --if you want the best pro- You need this big FREE ducts, the fastest shipments and In an antenna system within the in- j book. A practical goide to the most liberal discounts, write on fluence of electro- magnetic waves from 1 aucceasinactbeilding'St': s your letterhead for our catalog J' advanced hook -ups. s L a distant transmitter, there is set up j all newest Darts and kits 1 at prices far below others. within it a combination of radio and Send today. Build the newest Bets. Make more money. audio -frequency currents identical in frequency and characteristics with those of the distant transmitter which set up 102.128 S. Canal St Chicago the electro- magnetic waves. _(Turn to page 55) * Tested and Approved by RADIO AGE x RADIO AGE for October, 1925 The Magazine of the Hour 53 An IMPROVED Slide Wire Bridge (Continued from page 18) Watch For Announcement of frequency currents. This buzzer will then be mounted on one of the end pieces The Radio Age of the box, with the adjusting scree protruding through to the outside of the box. The buzzer will have terminals (B1) and (B2). Model Receiver An "ON " -"OFF" battery switch will be mounted on the same end piece of the box as the buzzer and will have terminals (SI) and (S2). In issue Age Two binding posts will be mounted the November of Radio you on the end piece opposite the one on will find the announcement of a fully which the above equipment is mounted illustrated article showing how to build a and will be designated (R) and (R1). radio receiver home. will be a five - Two binding posts will also be mounted at It on each side of the box. Those on one tube receiver, designed and thoroughly side will be designated (X) and (X1). tested by the technical experts of the and those on the other side (Y) and (YI) RADIO AGE staff. The instrument will then be ready to be wired. The circuit will bear the endorsement of Stranded, rubber -covered or braided, cotton covered wire should be used to this magazine and it will carry our own wire the instrument, as this wire is not name. as liable to come loose at the terminals or soldered connections as solid or bus Co-operating with the RADIO AGE wire. It is also necessary that some staff in designing this model set will be flexible wire be used for certain leads to make it possible to remove the cover, the engineers of leading manufacturers or panel, when it is necessary to replace of standard parts. All apparatus used the flash -light battery (E). This battery in this particular receiver will be specified should not have to be replaced for at least five or six months as the current under the trade names. drain from the average high frequency buzzer is only about thirty milli- amperes. The following wiring chart will simplify You will not want to miss this best the connecting up of the instrument and offers a good means to check the wiring technical radio feature of 1925 -1926. for errors. WIRING CHART See the November issue for further details. RUN ONE LEAD FROM TO TERMINAL Switch terminal (Si) Battery terminal (El) Switch terminal (S2) Buzzer terminal (B2) Buzzer terminal (BI) Coil terminal (I2) Battery terminal (E2) Coil terminal (I1) Coil terminal (I3) Pot. terminal (Pl) Pot. terminal (PI) Binding post (X) Coil terminal (I4) Pot. terminal (P2) Pot. terminal (P2) Binding post (v) Pot. terminal (R2) Binding post (R) Binding post (Yl) Binding post (Rl) Binding post (Rl) Binding post (XI) A piece of white bristol board, foi- the scale, will be cut into a disk five inches in diameter. A hole will be cut in the center to pass over the knob or sleeve of the metal dial (S). The scale should Shows how to get- greater distance, be marked on this disk so that when more volume, amazing selectivity, the dial is rotated as far to the right as finer tone possible, the dial marker will be directly Science has discovered a new principle in radio amplification a striking new over the "O" point on the scale and development that is bringing unheard of re- when it is turned as far to the left as sults. This principle is founded upon a new kind of coil -the Erla Balloon Circloid. It possible, the marker will be over the brings 4 distinct improvements. These are "100" point on the scale. A partial explained in a fascinating hook just puu- scale is shown in figure five, to exact lished and being mailed free. 701V/i CRIER Edition limited -Write toda,, size, and may be used as a guide in Get this book and read about this newest spacing the sections if desired. A scale scientific radio principle. See the many dif- five inches in diameter Jadio.'HosiBeau lSpeaker ferent circuits in which it may he used. Find smaller than may f out how you can turn your present set into be used if necessary, but the divisions You will be delighted with the gorgeous colors, the the latest example of radio engineering banasome -and will fall closer together than on the larger stippled finish, and the novel design of the at a remarkahly small cost. There are only TOWN CRIER - "the speaker witb the voice that a limited number of these books, so you must one and it will be more difficult to get a thrills." Ask your Dealer to show you a Town Crier write immediately. Speaker. Write today for beautifully illustrated cir- reading as accurate as with the larger one. cular, describing the Golden Polychrome and Green Address Electrical Research Laboratories, When the scale has been fastened to Polychrome models. 2500 Cottage Grove Ave., Dept. 6 -A. Chicago. III. dial (S) and the battery (E) has been List the Price, $17.50 R cldese $18.50 placed in the clips (details, figure three), RADIO'S LUCKIEST the panel will be made fast to the box GALE RADIO LABS. and the set is ready for operation. 2508 IRVING PARK BLVD. DEVIL ,(Turn to page 64) CHICAGO -In November Radio Age ' Tested mad Approved by RADIO AGE 54 RADIO AGE for October, 1925 The ?ilagasiNe_of the flour

, eorldt Standard Radio Receivers s Some time ago 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 MOOELB'G-2 the country have shown a keen interest in this new feature, and accordingly it is being made a feature of all numbers of RADIO AGE. Readers are invited r1Vew and Improv+ed to write us concerning the sets in which they are interested, and manufacturers FRE°"N also are asked to send us material describing their sets. NIASTE' 1'1E0 Day -Fan Five -Tube Receiver Five Tube Tuned Radio Frequency

Receiving Set. RHEOSTAT (K) AMPLIFIER CONDENSER NO. t TUBES VARIABLE CONDENSER NO. 3 CONDENSER NO.2 ANTENNA For dry or storage DETECTOR TUBE COUPLING battery tubes GROUND COIL

j'?II ._ As-.,jr-,.,r,ùra__ . .z ] ''w,._ `7 '! t ii/`\_1-_ r .00 WI/ r FILAMENT BATTERY, AUDIO ANrFNNA CONTROL SWITCH UCYERS ;;3959_ RHEOSTATS (, TRAN9FbR0FJì RADIO FREQUENCY SEA TRANSFORMERS aahotv Inside view of five -tube set

Built in a massive cabinet of striking lines and pro- portions, with sloping all Day -Fan sets the makers use the orchestra. Such tones are of vital im- panel. Accurate and care- IVDuoplex circuit, which is a develop- portance in bringing out the grandeur ment of their own laboratory. The four of orchestral and organ music and with- ful construction assures tube Duoplex has two stages of tuned out them such music loses a great deal. distance possibilities, sim- radio frequency, detector and two stages By the design and construction of Day - plicity of operation and of audio frequency amplification. The Fan audio transformers all of these low tone qualities unfound in five tube Duoplex has three stages of tones are faithfully reproduced with the radio frequency amplification (two being result that the music coming from the sets costing many times tuned and one untuned), detector, and Day -Fan is of great beauty and fullness as much. two stages of audio frequency amplifica- of tone. tion. The four tube circuit has five has.FresCSç tube range, volume, and selectivity. [,What to Expect From a Radio Set The five tube circuit has six tube range, The radio set today is a highly efficient FRESHMAN BUILDING a volume, and selectivity. Under favor- and truly remarkable instrument. When 240 -248 'Mar 4OTTt ST-NEW YORICÎr able conditions, Day -Fan receivers will CNICAOO OPTICS 327 S.LA IALLZ ST. properly operated it will give excellent - bring in any station anywhere in the results and will bring into the home - Sor Sale by AntÖorized United States, Canada or the West entertainment, instruction and news in a Dealen Only Indies when the desired station is broad- manner that was undreamed of four casting at 1000 watts or more. years ago. There are, however, certain The single dial control on the five tube conditions under which no radio set can sets is a distinctive Day -Fan achieve- give satisfaction. These conditions may ment. It has all the advantages of the be divided into two classes; those which three dial with the simplicity of single can be corrected and those over which dial control. It can be operated in the the operator has no control. Some of dark, and beautiful music is often most the conditions which the owner can greatly appreciated in a dimly lighted regulate for himself are: lG 15COUT room. The children can tune in just as L s well as the grown -ups, and yet none of 1. Your receiver should be made by a the advantages of the three -dial control reputable manufacturer who has the 9A have been sacrificed to attain this extreme organization and facilities for correctly ERS simplicity. designing and manufacturing so highly Write us -if you was to make more money on standard The exceptional tone quality of the sensitive an instrument kits, sets, Get is parts. our Day-Fan receivers due to very care- 2. You can select accessories of a BIG FREE CATALOG ful research and costly design and manu- which is the most complete deal- grade at least equal to that of your re- ers' catalog ever compiled. Stan - facture. We all know that there are many dard hnes at big discounts ceiver, as no receiving set can be better WRITE sounds above and below the range of or- FOR IT NOW: dinary music and to which our ears do than its accessories. not respond, but perhaps you had not 3. You can erect an efficient antenna realized that the radio receivers of the past and make a satisfactory ground connec- entirely excluded the pedal notes of the tion, as these are extremely important organ and the deep bass notes of the for satisfactory operation. ë' Tested soi Approved by RADIO AGI t RADIO AGE for October, 1925 The Magazine of the Hour 55 (Continued from page 52) Often two stages of radio frequency amplification are used to bring up the magnitude of this tiny current set up in an antenna system. The power to operate your receiver, therefore, does not come from the trans- mitting station; the energy received from the transmitting station is simply used to control the output of the "B" battery through the valve action of the grid of the vacuum tube. This valve or am- plification is somewhat similar to the valve effect of a water faucet controlling a stream of water. A child can turn on and off a faucet controlling 200 pounds of pressure. In the same way, the grid of a vacuum tube controls a much larger current flowing through the plate circuit, suppied by the "B" battery. If the radio frequency amplifier has increased the combination of radio and audio- frequency currents to a sufficient magnitude, the detector tube then smooths out the radio frequency com- ponent, so that the effect of the audio - frequency component only remains. Thus the process of modulation is reversed. The audio -frequency amplifier then per- forms its function of increasing the magnitude of this current. Finally, There's a Real Thrill it is converted into sound waves by the telephone or loud speaker, reversing the action of the microphone circuit of the in trying a New Hook-Up: transmitter. The vacuum tube plays an important VERYONE in the family part in each of these many steps. Any is eagerly waiting to hear the undesired variation in plate potential E set. new After hours and Bradleyswiteh- Perfeet introduced at any point at once affects hours of drilling and soldering, the Battery Switch the fidelity of ultimate reproduction. set is nearly ready for its first For this reason, "B" batteries are used crucial test. in preference to any other source of plate potential. The "B" battery relies Will it meet with your expectations or will upon electro-chemical action, contributed it be a disappointment? That depends upon within each cell two things -first your workmanship, and by billions of atoms second, the quality of the parts used. and its output is, therefore, continuous and unvarying. A generator depends Bradleys at-Perfect Good workmanship is the result of patience, for its action upon the sum of impulses Filamen Control but good parts are assured only by demand- for all Tubes ing well- known, guaranteed products, such set up in a number of inductances re- as Allen- Bradley Perfect Radio Devices. volving in a magnetic field. Some gen- Allen- Bradley products are known the erators have as many as 760 coils re- world over for exceptional performance and volving at a thousand RMP, but even fine appearance. They eliminate the hazard such a generator has variations in its and disappointment that follows the use of Bradleynier- Perfect output, which, when applied to the plate inferior radio products. Vernier Knob of the vacuum tube, produce a hum in Ask your dealer for Allen- Bradley Perfect the receiving set. Radio Devices if you value your time and labor. They always work! New "B" Power Unit Produced Bradleyleak- Perfect Grid Leak S; to in Megohms The Radio Units, Inc., of Maywood, Ill., announce the "B" RADIOPOWER ELECTRIC CONTROLLING APPARATUS UNIT. It is essentially an automatic "B" battery and not a "B" battery elimi- 289 Greenfield Milwaukee, nator, since it consists of a dry storage Ave. Wis. Bradleyometer- Perfect battery together with a trickle charging 0 Potentiometer arrangament built into a handsome Manufacturers of Graphite Din Rheostats walnut cabinet. for over 20 Years °1.1..a++1 They are also producing the PADDLE- .>.°° t WHEEL COIL, a new and superior type of inductance which was released to Use ¡ pttenBéóçietdÁve..so the trade late last season. Bradleyohm- Perfect g Adjustable Resistor Allen-Bradley gradtertlln- Mt yaD "Up in the Arctic with Radio rPi retlo` ... the Short waves. " -B y ...... Bradleyonit- Perfect Devices i Na*ne ' Armstrong Perry, in Nov. Fixed Resistor 1 RADIO AGE. -. --rT. Iii S`°°°° Taated tt4 Apps-oscd t4 sADZO 56 RADIO AGE for October, 1925 The Magazine of Me Hour

The Story of the Powerola Burns Concert Speaker Unit New WSBC Station Using Radio Now Ready Storage Batteries Powerola is electric radio without any The American Electric Company of Making its maiden bow and bid for batteries or chemicals whatever. It can Chicago now announce the marketing of popular favor is the 1,000 Watt Radio be used universally, operating directly an attractive new Speaker Unit -the No. Broadcast Transmitter sponsored by from the standard A. C. or D. C. light- 120 Concert model. This has all the the World Battery Company of Chicago, ing circuits in the home, office or plane excellent tone qualities of the No. 100 operating under Station Call Letters of business. By plugging into the house Burns Unit and in addition has a much WSBC on 210 meters, and constructed by lighting socket, the tubes in the receiver are greater range, being particularly adapted the Engineers of that concern. lit and the set ready for tuning. It becomes to reach the extremes of the musical The World Battery Company Trans- another electric necessity like an electric scale. mitter, as the new outfit is officially desig- iron, toaster, or other electrical device. With this Concert Unit it is no longer nated, is novel in many respects and For alternating current, two rectify- necessary to sacrifice those high notes or unique in that the power for the opera- ing bulbs (2 ampere), in connection with the low bass ones, which have hitherto tion is supplied entirely by storage bat- a transformer, condensers and choke in been lost and which left much to be de- teries, made up of identically the same these circuits, enables the receiver to sired in the quality of loud speaker re- materials as are used in the standard, obliterate all power -line hums and noises, production. stock batteries supplied to radio users and to deliver the required voltages and The exceptional tone quality of the for the operation of receiving sets. For watt power. For direct current a simple Burns Speaker has already won for it instance, the "B" or tube plate supply of but practical arrangement is employed thousands of enthusiastic users. In the 2,400 volts is furnished by the equivalent in connection with a choke, some con- Concert model a mellowness of tone of over 400 ordinary receiving 6 -Volt "A" densers and resistances, and with the combines most effectively with the ex- batteries made up of the same parts that filaments of the tubes in series, which also treme sensitiveness of the instrument. are used in the unit familiar to all radio smoothes out all generator hums and The slightest variations of sounds, the fans. By an ingenious switch arrange- noises, and produces the needed constants voice with all its fine shadings and the ment these can be connected in straight and potentials. There are no additional various musical instruments with their series to operate the set or in series paral- controls added on the rectifier or set to wide range of pitch are reproduced with lel for charging. compensate a variation in voltage on the exquisite trueness. The "C' or biasing batteries as well . 110 volt supply, A. C. or D. C. Powerola Remarkable tone volume is secured yet as those used for the microphone cir- is designed for A. C. 100 -115 volts, 40 -60 it is easily regulated to suit the occasion cuits are made up of the parts used in the cycles, and for D. C. 110 -120 volts. and to harmonize with the subject being standard 24 volt units such as are used Five standard tubes, such as the five reproduced. A convenient tone adjuster for the "B" supply in receiving sets. or six volt 201A or 301A, and standard is placed on back of mechanism case. Although the battery installation is a phones and loud speakers, are employed. The substantial size of this new unit good deal more expensive than is the The Terminal Electric Company es- and exactness of construction assures a equivalent motor generator set, it is felt tablished in 1910, for the past fifteen sturdiness and durability not otherwise that the additional expense is more than years has been manufacturing battery - obtainable. Rigid inspection is employ- compensated for by the clarity of trans- eliminating power devices. It is an old ed throughout the course of manufactur- mission, it being well known that the established, and highly regarded manu- ing. smooth steady flow of power from storage facturing firm. The value and security The Concert Unit is arranged with con- batteries insures a clearness that can of such an experienced precision manu- nectors for fitting any standard make of only be approximated by the generator facturer cannot be under- estimated. phonograph. system. Other exclusive features are Every piece of material which is of the incorporated in the design and construc- best and every stage of manufacture is Thomas Loop Distributed tion of the transmitter proper. thoroughly tested. Powerola has strength and charm, is built to last a Nationally New Straight 8 Out in Sept. life time and is fully guaranteed. The W. I. Thomas Company, fibre manufacturers of Chicago, have announ- Priess Announces Details of Daven Radio Corpor- ced they have na- Announcement has been made at the tion -wide distribu- offices of William H. Priess, president of ation Expansion tion for their line of the Priess Radio Corporation, that the Due to increased business and the loop aerials, known as company's new receiver, known as the necessity of giving the best service pos- "Thomas Selecto "Straight 8," was in production and sible to manufacturers, Daven distribut- - Loops." would make its appearance before the ors and Daven dealers, The Daven Radio 1 The Thomas loops, public in September, which on account Corporation recently adjusted their orga- one of which is illus- of the radio expositions, is popularly nization and made many new and import- trated in the accom- assumed to be the seasonal opening. ant changes. panying drawing, A good deal has been heard about W. H. Frasse, President, announces come in two sizes this set, for it has been known all along the appointment of K. R. Moses as Sales large and small. The- that the makers were aiming to produce Manager. Mr. Moses was previously model shown sells for a receiver of exceptional power; a distance Sales Promotion Manager of Crosley $12.50 and incorpora- getter and volume producer unmeasured Radio Corporation, and Sales Manager of tes all the latest de- by previous standards. the Amberola Division of the Thomas A. sign in loop aerials, Uncommon secrecy has been maintain- Edison, Inc. Mr. Moses has had twelve being the result of ed all during the experiments, which have years of phonograph and radio experience, several months' ex- run into many thousands over an unusual consequently the problems of merchan- periment. length of time. Besides Mr. Priess's per- dising radio are nothing new to him. Mr. W. I. Thomas sonal application and that of his labora- W. A. Balevre has been appointed has just announced tory staff, consulting engineering talent Advertising and Sales Promotion Manag- that exclusive Western distribution of has been employed to an unusual degree. er. Mr. Balevre has been connected the loops has been awarded the Radio - No descriptive statement of the with the Daven Radio Corporation for graph Laboratories, of 210 E. Ohio St., "Straight 8" has appeared as yet, and the past eighteen months and before that Chicago. Thomas loops are being na- it is understood that the makers prefer was with the Adams Morgan Co. tionally advertised this season. to let its performance talk for it. RADIO AGE for October, 1925 The Magazine of the Hour More Super Stations are Coming! (Continued from page 24) station into direct current, which is used for plate supply on the various trans- etter mitters. The modulating equipment i reception this may be connected with any of the smaller buildings by means of a system of over- head transmission lines. Speech and than last! music to be broadcast are obtained from the studio of WGY over an aerial cable circuit. It is further amplified at the WOULD you like better station before reaching the group of reception this fall and for metal tubes known as modulators. The winter than last? Better dis- transmitter to be modulated obtains its tance? Better volume? Better HOME plate supply in common with the modu- tone? You will enjoy better re- Use lator tubes through a group of reactors. sults in every way, this season, A dark room is provided in the main if you keep your tubes at full effi- building for developing oscillograph films ciency with the Jefferson Home recording modulation. A circulating Tube Rejuvenator. pump having a capacity of 150 gallons per minute supplies cooling water for all All tubes deteriorate rapidly metar tubes. The water is piped to all with use. The Jefferson Tube of the smaller buildings. Rejuvenator "brings them In addition to the rectifiers, a 12,000 back" in 10 minutes! Use itonce volt direct current generator is used for a month your tubes like supplying plate voltage for master -keep oscillators and other low powered equip- new. Completely restores ment. Generators supplying 4,000 volts paralyzed or exhausted tubes. and 2500 volts are used for plate supply Doubles and trebles tube life, to the smaller tubes. The filaments of quickly paying for itself through all tubes are heated by direct current. this great saving. gener- There are several direct current Takes large or small tubes ators of 300 ampere capacity at 33 volts - and 1000 amperes capacity at this voltage. types 201 -A, 301 -A, UV-199, At present there are two transmitters C-299, 5 -VA. Attach to any al- located in the main building -one is ternating current electric light operated at 50 kw. on 379.5 meters. socket in your home. The Jef- This transmitter is of the master oscil- ferson Home Rejuvenator for lator - intermediate amplifier - power tubes is as essential to satisfac- amplifier type using 20 kw. water cooled toryradio reception as a charger tubes in the high power stages. for storage batteries. Get one The second transmitter operating at now; start the season with your 1560 (2XAH) meters has a maximum of 40 kw. and is of the same general type s tubes inperfectcondition. Sold as 2XAG except that push -pull ampli- by leading dealers in radio sup- fiers are used in the power stages. plies, and fully guaranteed. The 109 meter transmitter is located in one of the smaller wooden buildings. JEFFERSON Circuits for this equipment are the Radio Transformers master oscillator intermediate ampli- 05 fier power amplifier type, in order to Your radio, no matter how of frequency. The high réIOin Canada costly, can be no better than obtain constancy its transformers. Our experi- voltage supply is carried from the main ence as the world's largest building to this transmitter by means of Jefferson Electric manufacturers of small trans- overhead-lines. Modulation for the 109 Manufacturing Co. formers is everywhere recog- meter transmitter is provided in Building nized by leading radio engi- 501 S. Green St., Chicago, Ill. No. 1 from the main bank of modulators. neers who carefully specify The antenna system is supported by Makers of Jefferson Radio, Bell Ringing and "Jefferson ". if you want am- Toy Transformers; Jefferson Spark Coils for plification without SO feet high, distortion three wooden poles each Automobile, Stationary and Marine Engines: -clear, pure, sweet, natural arranged in the form of a triangle. This Jefferson Oil Burner Ignition Coils and Transformers. tones from your radio -make type of antenna stucture has been em- sure it is equipped with Jef- ployed in order to permit a study of the ferson Transformers. Sold by various types of antennas which may be the better radio dealers, used suitable for operation at this wavelength. by leading set manufacturers. In common witl, all the other low wavelength transmitters, the low voltage and high current tnachine equipment is located in a separate building adjacent to the transmitter house proper. With fairly long wavelength transmitters the machine equipment can be placed in the sox transmitter house; with short wave- TUBE REJUVENATOR length transmitters it is necessary to not only spring -suspend the tubes but Keeps radio tubes like new remove the motor generator sets to a distant point in order to reduce the vibration to a minimum. g Tested and Approved by RADIO AGE 58 RADIO AGE for October, 1925 The Magazine of the Hour With the Manufacturers (Continued fr om page 56) The one serious problem in radio recep- New Eveready tion has always been the battery prob- "Layerbilt" a lem. Manufacturers have spent many Big Advance sleepless nights trying to develop a fool- The new flat cell "B" battery recently proof device that would eliminate either announced by the National Carbon Corn - the "A" or "B" battery, or possibly both. pany, makers of Eveready batteries, In most cases these devices were very utilizes the new principle of patented costly and had their weak points. battery construction by substitution of In solving this problem, a new and flat cells for cylindrical cells. There is untraversed channel of thought was con- about 30% more active electricity-pro - ceived by A. L. Levin of the Lestein Cor- ducing material than in the Heavy Duty of America, New York City. Amperite automatically controls tube cur- poration rent, eliminates hand rheostats, filament His idea was to make the tube itself, meters, guessing and all tube worry. which is necessarily of special construc- Simplifies wiring, tuning and operation. tion, do the major part of the work and Permits the use of any type of tube or any use a simple adaptor, which is not the combination of tubes. ordinary battery eliminator, which will Tested and used by more than 50 set manu- function to eliminate the necessity of re- facturers and in every popular construc- wiring a set that has been in service. tion set. RADIALL COMPANY DeptR,i410, 50 Franklin SL, New York City w. Write for t FREE Hook -ups

Jhe "SELF ADJUSTING "filteortat

't: a FFF battery No. 770 of identical external dimensions. It retails for $5.50 and is guaranteed to give considerably longer life than any other "B" battery of the Their new tube operates equally well same dimensions. More than 30,000 of on any 110 volt supply having either these batteries have already been tested direct or alternating characteristic. It in service from 30 contains two electron emitting surfaces, by users actual and to 52 %p longer life has been obtained which result in a far richer electronic under the same conditions of service as emission per unit of surface than is compared with any cylindrical cell obtained in the present storage battery same dimensions. type tube, which in turn tends to pre- batteries of the external vent 12-Cell 24-Volt the possibility of overloading. - The filament, which is lit directly from A Quiet Battery Charger Storage`B'Battery the 110 volt supply, functions also as a The Electric Company of Positively given free with each heater for an additional element, which Interstate purchase of a WORLD "A" St. Louis, Mo., has augmented its line Storage Battery. Yoa must when heated, emits electrons. The elec- send this ad with your order. tronic emission from the filament is of Battery Chargers by designing a WORLD Batteries are famous Twin Bulb Handy Battery Charger. for their guaranteed quality used for rectifying purposes and the emis- and service. Backed by years sion from the new element, surrounding The manufacturer states that this of successful manufacture and machine is quiet in thousands of satisfied users. it in the form of a circle, which measures absolutely operation inson with and is also a fast rate charger. Either a gaiinsstt acid` and leak. 1 -8 inch in diameter, functions in the MM. Yon rave 50per cent and nets same manner as the emission one or two of the bulbs in the machine 2-Year Guarantee filament may be used. When both bulbs are WORLDD t;A from the present day tubes. Bond in Writing Approved used it is possible to charge six volt ten their friends." That's om beet proof and Listed The general size and of of performance. Seed your order in today - appearance batteries at four to five amperes. Solid Rubber Cosa Radio Batteries as Standard this new tube is the same as that of the 6-Volt. 100 -Amperes . . $11.25 by Leading The Twin Bulb Charger charges S Volt. 120- Amperes. . 13.2S present day storage battery 201A type 6-VOIq 140.Ampero. . 14.00 Authorties efficiently both "A" and "B" batteries Solid Rubber Case Auto Batteries egg Radio tube. The standard four prong base is and will charge "B" batteries 24, 48, 6-Volt, 11 -Plate $11.25 NicladNews labora- used, 6-Volt, 13-Plate 13 -26 tories, Po lac and the internal elements are so voltage 12-Volt. T.Plate 16.00 tcteoó d- 72, 96, 120, in series. The Twin am t Stand wired to these prongs that the filament, Bulb Charger employs the advanced Send No Money'Twt ";d;óá Popular plate, we will obig day order ' received,- by Ex- Rdyades I and grid leads will connect to any "PUSH PULL" principle using both pre..a C. O. D. b,ect to yc examination [prise. RadioRadom v Lab. standard base socket arrttal- FREE "B" Batter I ded Brownan used with the pres- halves of the A. C. wave. fro Otter: per cent wdiscount toi mdse Radio ent ran with order.peser. BpeRow gat t yos.Ymd tri. Lome. day tubes. No moving parts are used in this tubed battery at ti0 per cent uvmg to yon. andLefas. Ive. WORLD BATTERY COMPANY Radio fans can control the workings of machine or liquids or vibrators of any 1219 So. Wabash Ave., Dept.36 CHICAGO, ILL. their sets without any technical knowl- kind. Naturally adjustments, corrosion Set rour Radio Dials at 210 edge or annoyance. The adaptor can and sticking trouble are eliminated. me for the new cation 1000 be easily connected with all radio receiv- This charger is fully enclosed in a beauti- W38C Chingó orlcl Watch ing sets on the finished metal case, with a l'ORAGE BATTERIES for aneomcemeec.. market today. The tube, ful mahogany will be known as the ' LESTRON" handle and accurate ammeter. sni, , t SsKMJsK s 31.111WATUS7s tube and can be used in any radio set The retail price will be $17.00 without and where ever the present radio tubes the bulbs, making it a reasonably priced ZILTRl3-VVRnIEf are used and will eliminate all batteries. charger. TUNING - C,ONTROL Armstrong Perry, Brainard Foote, Frank Pearne, H. F. A VERNIER DIAL. ON..Wít1ÇH, 'IOU. AN 'PENCIL RECORD THE STiCRdiei :,oe13REb solo r. SILVER. Hopkins, John B. Rathbun, Roscoe Bundy -"The Cream of pnlüt Saw -6ÓL0 .Phiyl5M.ùso - Radio Experts'' -All in November RADIO AGE ! PHENIX RADIO CORP., 116.F East 25 5t- N.Y. C. li Tostei sod Approved by RADIO AGE RADIO_AGE for October, 1925 The Magazine of the Honr 59

Consider what a Condenser is for! Your choice will be `rie BARRETT & PADEN Micrometer Condenser (for any Type of Set) OU USE a variable condenser to obtain certain capac- ity values in the tuning circuit. One measure of a con- denser's efficiency is the precision with which it enables you to obtain the various wanted capacities. The Barrett & Paden Micrometer Condenser will give you a wider variation of capacity values and far more accurate adjustment than any other condenser in the world, for the same reason that a mechanic's micrometer enables him to make infinitely closer measurements than he could with a rule. Get These Results! You will hear stations which have never had a place on your dials be- fore; tuning will be easier and selectivity much better; signals will be louder because of the extremely low loss characteristic of this condenser. Install Barrett & Paden Micrometer Control Variable Condensers in your set now. You will be amazed at the immediate tremendous differ- ence they will make in your set's performance. At your dealers or direct. .00025 -straight line wave length .00035 -flat wave length curve 00 including .0005 -straight line capacity dial

0005 BARFIETTfip PADEN 1314 Sedgwick St., Chicago, 111. Straight Line Prepared by Kirtland -En. ) Adv. Co., Chlc0Go Capacity The Best Plug at a Better Price The Pacent Autoplug Now 60c

THIS plug is entirely shock- proof, for the entire length of the cord tips is encased by the plug shell and no metal parts are exposed. The shell is made of genuine Bakelite. No screws are used in its as- sembly, and there is nothing to work loose or cause trouble. No. 60 Price 60c Pacent parts are used by 40 leading manufacturers in the construction of their sets. It will profit 'you to get in touch with us. See your dealer, and write us for the new Pacent Catalog of Complete line of Pacent Essentials. PACENT ELECTRIC COMPANY, INC. 91 Seventh Avenue, New York City

Washington San Francisco Philadelphia Jacksonville Minneapolis Chicago St. Louis Detroit Boston Birmingham Patent Buffalo Pittsburgh RADIO ESSENTIALS Canadian Licensees: \V "bite Radio Ltd., Hamilton. Ont. vial:DON'T IMPROVISE -- PACE TIZE'

* Tested and Approved by RADIO AGE 60 RADIO_AGE for October, 1925 The_Magazine of the Hour A Distortionless Audio Amplifier (Nan cin4ensers (Continued from page 16) Thus, the sockets may be fastened to a With The Pyrex End Plate panel or they may be screwed to a base- board with small wood supports between them -'r and the base, just sufficient to hold the resistance clips above the base- e tiiün board. Figure 1 shows a top view of this same unit attached to a 7x10 bakelite panel, which also carries the rheostat controlling all tubes, and the input and output ra jacks. These jacks cut out the entire amplifier, or cut it all in, as desired. The volume may be very nicely con- trolled by the rheostat, which also serves to turn the unit off when not in use. Parts Required THE material necessary to build the unit costs about $18.00, and is listed below. All parts should be of first class manufacture, particularly the resistances and condensers. Standard panel sockets should be used, which will accommodate either UV201A or WD12 tubes. ÚV199 iEs would have to be used with adapters, but this will not impair the efficiency of the set, though it does make for an excellent mechanical arrangement. De- Forest D V3 dry cell tubes will fit standard sockets, or the new ÚV199, soon to be out with standard bases, will fit the sockets recommended.

1 614 ohm rheostat 1 101 jack, I spring Furnished in strait_ rit line frequency and straight line wavelength design. The 1 102A 1ACI, 2 SPRINGS straight line frequency condensets spread all stations evenly around the dial accord- S INSULATED TOP BINDING POSTS _ frequency. The plates are so fashioned no excess panel space is required. 3 PANEL -MOUNTING SOCKETS . ing to that 6 .0075 CONDENSERS »w' The two to one helical gears assure sharpest tuning and smoothness of operation 6 GRID LEAK MOUNTS not possible where the dial is mounted directly on the rotor shaft - 3 T4 MEG. LEAKS I-' leakage paths on a genuine Pyrex end plate make the QUAM the lowest loss 1 3t MEG. LEAK condenser in the world. Sturdily built, with brass frame and plate soldered in place 2 i MEG. LEAKS 17 a 2 j x jj BAKELITE PANEL assure minimum resistance losses. Beautifully designed and finished, it is truly the 17 x 10 x BAKELITE PANEL condenser that will last a lifetime and constantly give satisfaction, LUGS. BUS-BAR, No. FLATHEAD SCREWS AND NUTS, SOLDER AND SPAGHETTI. .00025 $6.00 The panels should With 4 inch bakelite 360° dial, be prepared by drill- .00035 6.50 J} add $1.00 ing them in accordance with the drawing, .0005 7.00 Fig. 2, using the drill sizes shown, and QUAM Audio Transformers $5.00 countersinking holes where this operation is indicated. The smaller panel has some holes countersunk on one side, and some countersunk on the other. This is QUAM RADIO CORPORATION because the heads of the screws fastening the sockets come under the leak clips 1925 S. Western Ave. and condensers, and the screw heads Chicago, fastening these parts come under the U.S.A. sockets. Three- quarter -inch flat -head brass No. áz machine screws should be used. These will be so long as to interfere with the leaks where they are RADIO AGE SUBSCRIPTION BLANK used to hold the clips, when they may be Radio Age, Inc. broken off with a pair of pliers; or shorter screws may be used to hold the leak clips. 500 North Dearborn Street, $2.50 A YEAR I Chicago The assembly is started by putting through the sub -panel the six screws Gentlemen: Please enter my subscription for RADIO AGE. the Magazine of the Hour, or one used to hold the sockets, but not fastening year, beginning with your next issue, for which I enclose $2.50. the sockets to them with nuts. Then, with these six screws hanging loose in Name their holes, the four condensers and six leak clips are screwed on to the sub -panel StreetAddress_._..-.....---.-._"------.- ..__...__.__ by putting flat -head screws through it from the other side. After this has City_ been done, the three sockets may be placed in position, and nuts tightened State_ up on the six screws used for holding Send cash, money order or draft. them. A reference to Figure 3 will show RADIO AGE for October, 1925 The Magazine of the Hour 61 how the parts are put in place on the sub -panel, and just how lugs are put on the leak clips and condensers. Lugs are shown on some condensers, and if solder- ing paste is to be used, the wiring should be run to these lugs, and not to the condensers. If no paste is used in solder- ing to the condensers, the wires may be soldered direct to the small rivets used for holding the brass plates of the con- densers together. The five binding posts are put on the sub -panel as shown in Fig. 3, with lugs under the screw heads as indicated. The wiring may be started, using a well tinned iron, rosin core solder, and a small quantity of non -corrosive paste. Each lug should be tinned separately and each wire should be bent and cut for its position before any attempt is made to solder it in position. It should be á. tinned first at points where it will be tn. iYrs for Power soldered to a lug. Operation If you want distance and clear tone from your ONCE the amplifier has been comple- radio set, your storage battery must have its ted, the proper batteries need only partner -the Tungar Battery Charger. be connected to it, the tubes inserted, and the unit connected to a set and loud Two clips and a plug to connect to the house speaker, and it will work. However, current. That's all there is to it. Or you can before connecting it for operation there make permanent connection and just throw a or tests to make. First, the are one two The Tungar is a GE switch. A battery should be conlected to its product developed in the great Research Labora- posts, the tubes inserted, and the rheostat toriesofGeneral Electric. The Tungar charges while you sleep-it makes tubes will light; ,if all turned on. The The new Tungar charges no disturbing noise -keeps your batteries at top connections are correct. If they do, 2, 4, 6 volt "A" batteries; the wire, and connect it 24 to 96 volt B "batteries, notch. For power there is nothing like a good disconnect A+ in series; and auto bat- to the b+ post. The tubes should not teries, too. No extra at- storage battery -with a Tungar to keep it good. light, and if they do, there is an error in .'tachments needed. the wiring which must be corrected. Two ampere size (East of the Rockies) . $18.00 Assuming they light only when the A 1 battery is connected to its proper posts, 60 cycles -110 volts a 90- or 135 -volt B battery should be connected to the posts marked for it in the diagram. Two or three 45 -volt batteries will give this voltage nicely. If the same batteries are to be used on BATTERY CHARGER the amplifier that operate the receiver, these will generally consist of the neces- Tungar -a registered trademark -is found only on the genuine. Look sary A battery together with 9Q volts of for it on the name plate. B battery. If this is the case, the simplest way to connect the amplifier is to run Merchandise Division two wires from its A+ and A- posts, Ceneral Electric Company, Bridgeport, Conn. j' to the A+ and A- posts of the receiver. Then, if no more B battery than is used on the receiver is to be used with the amplifier, the B+ post of the amplifier need only be connected to the B + post GENERAL EI.EC?'IE of the receiver. If additional voltage is to be used on the amplifier -say 135 volts where 90 volts is used on the re- ceiver-an extra 45 volt battery should be connected with its plus lead to the B post of amplifier its minus Cop plus the and Tie'7raffc FERBEND lead to the plus B post of the receiver. of the In no case is it necessary to make a Add a Ferbend Wave' Wf/JiJ6W71 to your Radio Set Ra( t os' connection from the amplifier to the Trap mep SigMousygaving R and "Pobce 'your conta n F thousand b n B -, as the B - is always connected to non Regulate traffic r taiog in radio; p tar off, Guaranteed to tune out itlll plete parta for e ' ts. the A battery at the receiver. This any interfering station. etc.. also at- Widely imitated bat ill t inform, fi( return may be connected in the case of never equalled. The ferent Circo and oa suc- (II JI'. üri r 11 á the receiver to either the plus or minus cessful WAVE TRAP.df therrvd aaSSGN_ side of the A battery, but in any case Now in its third year. Ii Easy to build. raata 1 { Sent Postpaid n on i romp fs 9r -d it will be fed through on the common elppt or SA 60 or . o n Itiliat Atilt' Stil plus Postage. Send far Free Book[ t II,',, I 1 A battery wiring to the amplifier. It i'7. k .t gdrilled b MIÌO, t. 15 fi. So. WaterSt.ECTRIC Chicago .II,ii'i it .II.IJI , `,' mg dlgrama ppor a is of very little importance whether this Eventhln {uariiii -,.' ;C4 B return is connected to the plus or teC v Send name, address ia- minus lead of the A battery, so whatever og. en i names of friends; we will mail' gs. OAnLP, A c seonar,.,.. AGO wiring is used for the receiver will do tae earh URnAiNO a eR. OI,OP . 4o4 for the amplifier. Read Radio Age * Tested and Approved by RADIO AG4 62 RADIO AGE for October, 1925 The Magazine of the Hour Every How the New KYW is Radio Fan Getting Power should have this (Continued from page 30) determines and holds the wavelength D M PLEA constant and which is impedance coupled book to the antenna. A development of the Hartley oscillating circuit is used and the modulators work on the Heising prin- 100,000 SOLD ciple. 514 PAGES The impedance or choke coupling between the tank and the antenna cir- Compiled by cuits is considerable of an advantage to HARRY F. DART, E.E. the radio listeners, because it secures CONDÉNSERS Formerly with the extremely loose coupling of the trans- We. ter n Electric mitter and the choke eliminate prac - Made according to Bureau :of Co., and U. 9. Army lmtructor of tically all energy in the harmonics which Standards specifications for low- Radio. Tech- have been a source of trouble in the past. est losses and best nically edited by electrical F. H. DOANE. The antenna is composed of two 3% characteristics. inch horizontal cages, 140 feet long and supported by two 125 feet steel towers. Specially shaped -out stator BE A RADIO expert -it's easy for the 100,000 The down leads are two similar cages plates space the stations over who own this compact, complete Radio Hand- hook. Written in good, plain. understandable and connect the antenna to an open cir- the dial, while keeping the language. Crammed full of facts, every one use- cuit tuning inductance near the base condenser as small as a straight - ful and important. Explains bow receivers and of the south tower. The counterpoise transmitters work, how to build and operate line capacity model. them. Whatever you or your friends want to is a 10 wire fan, radiating from the south know, it's here. Will save you many times its tower to points equally distant, entirely Aluminum stator plate, exactly small cost, around the hotel roof. More than 1% the same as used in the new TELLS ALL ABOUT: Electrical terms miles of hard drawn copper wire went into DUPLEX Straight Line and circuits, antennas, batteries, g Fre- tors and motors, electron (vacuum) the construction of the antenna system. quency condenser, sent on re- tubes, most receiving hook -ups, radio and audio frequency amplification, broadcast 50 Pairs of Wires! quest. Write for one today. and commercial transmitters and receiv- Learn the secret of DUPLEX ing, super- regeneration, codes, license cables each containing fifty superior . construction. rules. Many other features. rriWOpairs of telephone wires connect the new KYW station with the several Duplex Condenser & Radio Corp. Nothing else like it. Make this extraordinary book studios and the numerous outside points your radio library -just this one little giant Is all from which programs are broadcast. 42 Flatbush Avenue Extension, you need. Everything in one index, under one cover, in one book, for one dollar. The cables terminate on a large telephone Brooklyn, N. Y. Just mail the coupon with a dollar bill and your test board, through which telephone name and address, and this 514 -page I. C. S. Radio lines may balanced and equalized to Handbook will be sent to you by return mail. Note be the other good hooks listed below at low prices. pass all the complex voice and musical frequencies from 50 to 6000 cycles. Provision is made on this board for 1 INTERNATIONAL CORRESPONDENCE setting up phantom and simplex circuits SCHOOLS Box 878541. Scranton, Penna. over any line so that studio equipment I enclose E for which send me, post -paid, may be remote controlled and adjusted the Handbooks marked X. at $1 each. It is under- stood that If I am not entirely satisfied I may from the station. The telephone test return them within five days and you will refund my money, board is connected through plug and a smaller board on ['RADIO HANDBOOK, 514 PAGES, jack arrangement to $1 the operating desk, only the circuits to Automobile Handbook. 11 D leyElectricaltall 45essee be used that day coming in on the Chemistry Handbook, 348 pages - SI Want to make big, easy money? Learn Pharmacy Handbook. 324 pages - - operator's board. By means of this how to install, operate,repai r, construct Traffic Handbook. 388 pages small switchboard he is able to change and sell Radios. Write now for facts Building Trades Handbook, 409 pages about the amazing opportunities for Machine Shop Handbook. 335 pages Ét from one studio to another, talk to any Radio experte, D Salesman's - and our special offer of a pages SI 1000 -mile Advertising Handbook.. 445 pages - SI studio or connect back the output of one FREE receiving set, and how Bookkeeper'. an 30 pages - 81 you can quickly train at home by mail. Civil Fi n eis Handbook, 911 pages studio into another so the waiting artists m Engineer's Handbook, 2913 Pages :1 Be a Radio Expert there may hear the program. No previous experience necessary. Anyone A small, well arranged, control desk with ordinary edscation can now learn Radio Name gmkklynnderonrsimplined home -etndy plan. starts, stops, and adjusts the entire We need men tight now to represent our Association. Be the Radio expert in your station as well as handles the programs neighborhood Get your share of the big Address coming in over the telephone lines. The profits. Hundreds abontyon want Radios and Enclose $1.50 for each book if vos scant the advice how to operate. You can earn enough Leatheroid binding. All of the above books eon operator need not leave his chair to test money right from pay courier. be hod in this binding creme the Tragic Handbook Nothing dttodifficult forabout . L0M the Building Trades Handbook. any part of the equipment or to take Low cost and easy terms. care of any of the manifold details in- cidental to operation. A bank of amplifiers or repeators FREE within easy reach of the operator pass the 1,000 -MILE N_ ew Perpetual LOG incoming voice current through tubes Receiving Set special offer to supply NEW 64 page log. Lowe leave. so can be kept progressing from a few watts in the first Don't mise this big . rr, p.to-date. Corrected sheets may he secured FREE all parts necessary to construct a = eS changes le calls. Wave lengths, owners, ate. stage to four fifty watt tubes in the last high -grade 1000 -mile receiving set. You can -t. V= . Holds 604 etanons. Shows call, city, sell this set alone for practically the entire -. lengths. 4 dal sett remarks. etc. tacts TUNING SUGGESTIONS. Station list by stage. The volume of the voice current cost of the course. Send for the lengths-by states. etc. Owners. TROD. FindFi ont all about this big -pay field. Address ELÉAIDS. Other valuable information. Soon. is many times multiplied in this manner v venient. Worth 01119e i tmes small cost. A joy to Radio Association of America r. oDn d until it reaches a value sufficient to actuate 4513 Ravenswood Ave., DepL 210 Chicago, 14 d Y REFUNmaa LGXÉDOdr od -ÓW, the four water cooled modulato tubes. RADIO PRINTERS. Dept. 2027 Marengo, Illinpa KYW is now on an equal basis with her older sisters, KDKA and WBZ, Coming ! and is prepared to put a consistent Have You Bought Your signal of the highest quality into the The Radio Age homes of the middle western listeners -in Receiver! ANNUAL ? throughout the entire year. * Tested and Approved by RADIO AGE RADIO AGE for October, 1925 The Magazine of the Hour 63 FREE Subscriptions to RADIO AGE For Your Time! Radio Age will give a year's free subscription to this mag- azine to any reader who will obtain for us a news -dealer who will handle our magazine in a town where we are not already repre- sented. If you are now a subscriber to RADIO AGE, you can refer this notice to one of your friends, who GUARANTEED FOR LIFE! will doubtless be pleased to take Folds to Any Position - THE ACCURATUNE advantage of this opportunity. Wires Always Taut Or you may extend your own sub- is ideal for coarse or ex- scription for one year without cost. The newest addition to the line of quality Radio Accessories. Made of the highest grade materials tremely fine tuning, segre- This offer is to remain in effect throughout in a new and masterly design. Specifica- until further notice. tions: Length, 24 inches, Normal Ht., 30 inches, gating even those stations Wavelength range 120 to 600 meters. now so closely grouped on The "AALCO" the lower wave lengths; it Free Subscription Blank Is different both io appearance and operation. You brings them in with ab- RADIO AGE' Inc , will find that the new loop adds to the performance 500 N. Dearborn St., Chicago, of your set. If your Dealer cannot supply you send solute precision. Volume Gentlemen: In order to get a free sub- money order, and we will ship direct. LIST PRICK, scription to RADIO AGE for one year. 515.00. and clarity are matters of - JOBBERS: Write for our proposition I herewith send you the name of a dealer course to the Accuratune. who will sell RADIO AGE in the city men- AALCO RADIO LABS. tioned. It is understood that if you already 6350 Cottage Grove Avenue CHICAGO Quickly substituted with- have a dealer in this city that the offer of a out alteration of your set. free subscription does not hold good. Dealer's name -Radio Nut's Headquarters -Parts only, no MYDAR RADIO CO. sets. $20,000 stock. Most comprehensive. 11 17 CAMPBELL ST., NEWARK, N. J. Street No. you can't find it, ask us. Weekly latest "dope" -10 wks. 50c. "change your Neut" Kit-$5 prepaid. Particulars -10c. 48 page Cit .... State parts catalog-10c. Knock Down Loop Kit- $7.50. 150 v., 55 milamp B Eliminator, off My name 110 v. a. c., knock down kit including 2000 CCURATUNE: hr. Z 50 tube- $36.55. Assembled, ready to aemsre.eo u+rr ore use -$40. Data -10c. Kladag Radio Labora- City ...... State (10-25) tories, Kent, Ohio. ORIOLE* RADIO RECEIVERS

Model 7 5 Tubes Model 8 4 Tubes Model 7 5 Tube Highest Known Selectivity A New Development No Lossers Employed Visit Booth 24 at Chicago Show W. K. ELECTRIC CO. KENOSHA, WIS.

* Tested and Approved by RADIO AGE .' 64 RADIO AGE for October, 1925 2' 'he Magazine of the Hour viRereM How to Make a New Slide The CREST CONVERTIBLE CONDENSER Wire Bridge (Continued from page 53) Adaptable The operation of the slide wire bridge to ANY Armour Institute is simple, As previously explained, Circuit all Tests Showed: that is required will be to connect an Maximum capacity .000522 ordinary set of head -phones to the bind- ing posts (R) mfd. or .22 mfd. rated and (R1) and turn the above switch (SW) to the "ON" capacity. Minimum capacity position. The coils or condensers to be matched of 23 plates .00011. Ohmic or balanced will be connected to the resistance .18 ohm over labora- binding posts (X) and (X1) and (Y) tory standard due to special and (Y1), as directed in the following construction features. examples. Balancing Transformer Is adaptable to ANY circuit, for the number of plates may be 1f dealer cannot supply you, TO BALANCE the coils of a trans- changed at will from 23 plates down to 2 plates. It will balance your circuit perfectly. Plates can be removed and cleaned plate send his name with your re- -11- former or other type of inductive for plate. Straight wave line -equal spaces on dial. Made of mittance and we will supply coil, connect the inside terminal of solid -workmanship one brass and materials guaranteed. you direct. Inquiries invited of the coils to binding post (X) and the 23 Plate -$5.00 from dealers, jobbers and outside terminal manufacturers. of the same coil to Two finishes -Nickel Silver or Natural Brass. binding post (X1). The same procedure will be taken with the other coil except the terminals will be connected to bind- ing posts (Y) and (Y1). The switch CREST RADIO CORPORATION (SW) will be turned to its "ON" position 5 N. Waha.h Avenue, Chicago and the dial rotated to the right or left until no tone is heard in the head phones. If the silent point falls on 50, the im- pedance of the coils is the same; if the silent period shows a dial reading of 40, the coil connected to the binding posts (X) and (X1) a S 96 -PAGE has greater impedance RADIO GUIDE BOOK than the coil connected across binding Profusely illustrated, posts (Y) and (Y1) and it will be neces- "chockful" of data for the radio fans. sary to add turns of wire to coil (Y) Trouble Shooting Chart. until the dial reading shows 50 at Complete New List of the Breadcasing Stations silent period. Log Chart If the dial reading should fall on 60, -and detail, of n wet app.tratu, and hundreds of the coil connected across binding posts Exceptional (Y) and (Y1) will have an impedance Radio Values LT, greater than coil (X) and it will be neces- MONEY BACK GUARANTEE sary to remove turns of wire from coil Frein bus bar to the finest multi -tubs set, we carp one quality - THE FINEST' EVERY arrticleesrepresents 100 rents worth of (Y) to match it with coil (X). When it value for is gvncallteed- Your MoneEVERYTHINGti O Moneymug is desired to match a coil or winding with till you are thoroughly .atirfied in every way. a coil or winding that is not to WRS IS HEADQUARTERS FOR KITS AND SETS be changed Cockaday Super Neutrodyne it would be well to get into the habit of á Cockaday O.X. r EVERYER Superdyne STANDARD Pressley e Ultradyne RECEIVER Super considering the coil connected to bind- Roberts' KnockDut Rasta ing (Y) and (Y1) de bona, posts as the master FREE A sta yon nothing Write fer it TQDA and always work coil (X) as the variable WHOLESALE RADIO SERVICE CO. or coil to be balanced. 6 Church St. Cat. R. A. 10, New York City lig To balance more than two coils or A Six Tube windings, the first two will be balanced as above and coil (X) will be removed; Ei IN CONSOLE 1 the third coil will then be connected to the binding posts (X) and (Xl) and be $125 LIST' balanced in the same manner. (With Loud Speaker) 4 Transformers or coils so matched or balanced will have characteristics similar enough to fall within a few meters of one DIANA "SIX" another and should work well together. RADIO A perfect set in a beautiful cab- Balancing Or Measuring Capacity Storage "B" Battery inet. A real six tube set. Two To measure the capacity between iá$ miss Lasts Indefinitely -Pays for Itself a Economy and performance unheard of before. Recharged $100 list. windings of transformer, the same pro- at a oegli bible cost. Approved and listed as Standard by models. Cabinet Grand lending Authorities, cedure will be followed as for measuring Init. Standards. Radio ab ,_ 1, ttitil- IEncc..b-and other tim as shown above with portent iratitutlon,. Equipped with Sala Bubb. 'Cane moor. Console impedance, except that the inside ter- dOrd yours todafea bean Äean. rugged ppiatta r glass loud speaker, $125 list.. A long minal of the primary coil will be con- SEND NO MONEY lost state number of hot erèas nected to binding post (X) or (Y) and order In received. Extra Often 4 battrrieu In aeriessGvolbihS12i6. distance set. Easy to tune. 6 par ern` dlsmaat rtf of P sh wÌW order. afti yourátrderb flow"ca' the inside terminal the secondary WORLD BATTERY COMPANY coil connected to binding post (Xl) 1219 So. Wabash Ave., Dept.sa Chicago, IlL Exclusive Territory Open Makers of the Famous World Ra A' Storage Basler, or (Y1). The dial will be rotated until Priam 6-gott.100 Amp. 811.2.5. ¿CO Am 8,9.2.5. 140Ám». 81/00 Write Discount and splendid Al rouipped tua Rutkw Case. for Liberal the silent period is located and a balance Sales Proposition. Booklet R -A upon Set your Radio Dials at 210 obtained as was done for impedance; mueca for the new 000 request. watt torah, Battery if the reading should fall on 50, the coils ilion r meneo. W®rl en announcements. if falls on 40, d wa for announcements. it the capacity STORAGE BATTERIES DIANA RADIO COMPANY are matched, T NV- EAE -W6N sWJSeHILIsT(6-0- KipFIIZ)PiÓ 1429 So. Michigan Ave., Chicago (Turn to page 65) Tested and Approved by RADIO AGE RADIO AGE for October, 1925 The :Magazine of the Hour 65

between coils of the transformer (Y) is greater than that of coil (X) and the windings will have to be placed closer together or the dielectric material be- tween the coils will have to be changed ,. . , until the reading shows 50. SüPER ` 141 t To measure the capacity of a con- denser, a condenser whose capacity is PÁRTS known will be connected across binding posts (X) and (X1) and the condenser Better Results to be measured will be connected across binding posts (Y) and (Y 1) the same From 3 Tubes operation will take place as on the other measurements except in determining the capacity. This will be done by Than From 5 reading the dial and working the follow- ing formula- assuming the capacity of passing the incoming Real S -L -F Condensers at Instead of condenser be .5 mf. signal once through each of 5 the master to last) Silver -Marshall have tubes, Crosley design, in the dial reading 25, then the capacity of met the demand for an all - Super-Trirdyn, passes it through condenser (X) will be greater than that round straight -line- two of the three tubes several of (Y) as explained in "Thompsons" frequency condenser by pro- times, each time building up its method. To charge two condensers of ducing an instrument that strength and adding to its unequal capacity with equal quantities meets the requirements of volume. lowest losses, small size, of electricity requires a higher E. M. F. attractive appearance, and Even the technically uninitiated applied at the terminals of the smaller see the advantages: sim- -most important -actual can condenser, that is, the E. M. F. applied S -L -F tuning efficiency. All plicity instead of complexity; at the terminals must be inversely pro- types supplied with pulley fewer dials to adjust; sharper from one to accuracy in selecting stations; portional to the capacities. collars so that greater clarity; greater volume, From this, it will be seen that a greater five condensers may be con- greater ease in logging stations. amount of electricity is being applied to trolled by a single knob, the condenser (X) than to condenser without separate verniers. The S are This simplicity of design com- (Y); therefore condenser (Y) is three -M Condensers bined with the economies of entirely silver- plated -a gigantic production makes pos- times as large as (X) from reading the feature that reduces losses sible a price of $60.00 on the dial as (Y) =b x (X) or 1.5 mf. For a lower than laboratory stan- Super -Trirdyn Special, the most graphic explaination of this formula dards. efficient and beautiful of all see figure two. i No. 310 .0005 $6.00 Crosley receiving sets. For Impedance of No. 311 .00035.._ 5.75 Crosley is the world's largest Measuring Inductive No. 312 .00025 5.50 builder of radio sets- owning Coils S-M and operating parts factories, To measure the impedance of a coil, cabinets woodworking and as- Type sembly plants. a coil whose impedance is known, will be connected across the binding posts 210 Write for illustrated catalogue. (Y) and (Yl) and the coil to be measured and Crosley dealers everywhere. will be connected across binding posts (X) and (XI). The same operation will 211 Crosley manufactures ro- Add 10% to all prices ceicing sets which are West of Rocky Mountains. take place as on the other measurements Trans- licensed under Armstrong Crosley owns and operates except in determining the impedance; formers U.S. patent No.1,113,149 I11W first ramose control this will be done by reading the dial and and priced from $9.75 to super-power broadcasting S 210 and without accessories. station. working the following formula- assum- The famous -M $60.00 211 Intermediate transfor- ing the impedance of the master coil to mers, used in the receivers be one henry, dial reading 60, then the developed by McMurdo impedance of the coil (X) will be )1x(X) Silver and in several other GRO-SI-EY RADIO or, substituting the values of the scale well known designs, pro- S E t T F ft C O S T S L E S S readings a =60. From this, b would be vide the highest amplifica- 40, as in the schematic diagram, figure tion of any transformers on THE CROSLEY RADIO CORPORATION two; b =100 -a. The formula would the market. Each trans- Cincinnati, Ohio 6°exl former is laboratory -mea- then be henry =Y or .66 Henry. sured and supplied with in- f Many other forms of measurements dividual curves-your guar- may be made on this instrument as well antee of uniformity! The as those mentioned above. The same new bakelite case is es- formulas will be used, slightly modified, pecially attractive and effi- remembering that the dial reading will cient. Filter furnished with Build Your. Own- take the place of "a" and that "b" will measured tuning condenser. 'p always be the result of subtracting the Transformers supplied in amount of a from the entire scale of the sets of two 210's and one 1 211. bridge, which is 100. From this, it Each - -. ..._..- $8.00 SAVE 550 to $100 dollars-build your own will be found that if "a" =25 which Send 4c in stamps for circulars Radio Set -NO EXPERIENCE NECES- would dial reading, describing the latest S -M develop- SARY. New up -to -date book, "Radio Fre- be the then "b" ments, including the new cushion- quency Amplification." written in simple will be 75 or the sum difference between ed sockets for UX and UV tubes language, gives latest diagrams and hook- reading of 25 and the interchangeable coils for ups to select from, with full instructions. the dial and the scale of all -wave receivers. Magazine re- Tells parts necessary for large or small 100. prints describing the super -auto- sets. Nothing like it ever published be- To accurately measure resistance to dune and the all -wave super are fore. Worth 10 times the price to any free! Radio builder. Sent postpaid (stamps ^ direct current, it would be necessary coin) or receipt of only ---- to connect a galvanometer across the Silver - Marshall, Inc. P. G. WERNER RADIO terminals (R) and (R1) and to connect 114 S. Wabash Ave. MFG. CO. Chicago, Illinois 204 -206 Ninth St., the small battery across terminals (I3) Brooklyn, N. Y. and (I4), with the switch (SW) in the (OFF) position. f3 Tested and Approved by RADIO AGE 66 RADIO AGE for October, 1925 The Magazine of the Hour Corrected List of Broadcasting Stations

KDKA Wesrioshouee Electric & Mfg. Co... East Pittshurgh, Pa. 309 KFWA Browning Broc. Co Ogden, Utah 214 KDLR Radio Electric Co Devil, Lake, N. D. 231 KFWB Warner Bros. Hollywood, Calif. 252 KDPM Westinghouse Electrio & Mfg. Co...... Cleveland, Ohio 270 KFWC L. E. Well Upland, Calif. 211 KDYL Newhouse Hotel Salt Lake City, Utah 250 KFWV Wilbur Jarman 385 58th St. S., Portland. Ore. 212 KDZB Frank E. Siefert Bakersfield, Calif. 240 WGBU Florida Cities Finance Co Fullord By- The-Sea. Florida 278 KDZI Electric Supply Co Wenatchee, Wash. 360 KFXB Bertram O. Heller Big Bear Lake, Calif. 203 KFAB Nebreka Buick Auto Co.,l3th & Gust/. Lincoln. Nehr. 341 KFWD Arkaoeas Light & Power Co Arkadelphia. Arkansas 266 KFAD McArthur Bros. Mercantile Co Phoenix Aria. 273 KFWF St. Louis Truth Center St. Louis, Mo. 214 KFAE State College of Washington Pullman. Wasb. 348 KFW H F. Wellington Morse. Jr Chico, Calif. 254 KFAF Western Radio Corporation Denver, Colo. 278 KPH! Radio Entertaiomeoe. Inc South B. Francisco, Calif. 220 KFM University of Colorado Boulder, Colo. 360 KFWM Oakland Educational Society Oakland, Calif. 224 KFAN University of Idaho Moscow, Idaho 230 KFWO Lawrence Mott Avalon, Calif. 211 KFAU Boise High 8ebooi Boise. Idaho 271 KFWP Rio Grande Radio Supply Home Brownsville, Texas 214 KFAW The Radio Den (W. B. Ashford) Banta Ana, Calif. 280 KFW U Louisiana College Pineville, La. 238 KFBB F. A. Buttrey & Co. Havre, Mont. 360 KFXC Santa Maria Volley Railroad Co Santa Maria, Calif. 210 KFBC W. K. Asbill Ban Diego. Calif. 278 KFXD L. H. Strong Logan, Utah 205 KFBG Finn Presbyterian Church Tacoma, Wash. 250 KFXE Electrical Research & Mfg. Co Waterloo. Iowa 236 KFBK Kimhal1 -Upson Co Sacramento. Calif. 283 KFXF Pikes Peak Broadcasting Co Colorado Springe. Colo. 250 KFBL Leese Broa Everett, Wash. 224 KGB Tacoma Daily Ledger Tacoma, Wash. 252 KFBS School Distract No. One Trinidad, Colorado 238 KGO General Electric Co Oakland. Calif. 361 KFCB Nielson Radio Supply Co Pho.rn . Aria. 238 KGU Marion A. Mulrooy Honolulu, Hawaii, Waikiki Beach 370 KFCC The First Congregational Church Helena, Mont. 248 KGW Portland Morning Oregonian Portland. Oree. 491 KFCF Frank A. Mure Walla Walla, Wash. 256 KGY St. Martins College (Reh. Sebastian Ruth) Lscv, Wseh. 253 KFCZ Omaha Central High School Omaha, N.hr. 258 KHJ Times- Mirror Co Los Angeles, Calif. 405 KFDD St. Michaels Cathedral Boise, Idaho 252 KHQ Louis W Seattle, Wash. 273 KFDH University of Arizona Tuoop, Ans. 368 KJR Northwest Radio Service Co. Seattle, Wash. 384 KFDJ Oregon Agricultural College Coredlia, Oreg. 254 KJS Bible Imtltute of Los Angela, Ina. Los Angeles, Calif. 293 KFDM Magnolia Petroleum Co Beaumont. Texas 315 KLDS Reorganised Church of Jesus Christ of Latter Day Saiots. Independence, Mo. 441 KFDX First Baptist Church Shreveport, La. 360 KIS Warner Brother. Radio Suzanne. Co Oakland, Calif. 242 KFDY South Dakota State College Brookings, 8. Dak. 360 KLX Tribune Publishing Co Oakland. Calif. 508 KFDZ Harry O. Iverson Minneapolis. Minn. 231 KLZ Reynold. Radio Co Deaver. Colo. 283 KFEC Meier & Frady Co Portland. Oreg. 248 KMA KFEK Angehury Seminary Minneapolis, l(Bno. 261 KMJ Ban Joaquin Light & Power Corp Fresno. Calif. 243 KFELQ Winner Radio Corp Denver, Colo. 254 KMO Love Electric Co Tacoma, Wash. 250 Oak, Nehr. 268 KNX Loe Angeles Evening Express Loe Angeles, Calif. 337 KFEY J. L. Sc Hillo ,r & SO" Ivan Mining and Concentrating Co Kellogg. Idaho 233 KOA General Electric Co Denver, Colo. 323 KFFP First Baptist Church Moberly, Mo. 260 KOB New Mexico College of Agriculture & Mechanic Arts, State College, N. Mex. 348 KFFV Gracelared College Lamoni, Iowa 280 KOIL Monarch Manufacturing Co Council Bluffe, Iowa 278 KFGB Heidbreder Radio Supply Co Utica, Neh. 224 KOP Detroit Police Department Detroit, Mich. 286 K FGC Louleisoe State University Baton Rouge. La. 254 KPO Hale Bros Sau Francisco, Calif. 428 KFGD Chickasha Radio & Electric Co Chickasha, Okla. 248 KPPC Pasadena Presbyterian Church Pasadena, Calif. 229 KFGH Leland Stanford University Stanford University. Calif. 273 KPRC Houston Post- Diopetoh Houston, Texas 270 KFGS Crary Hardware Co Boone, Iowa 226 KQP Apple City. Radio Club Hood River. Oregon 270 KFHA Western State College of Colorado Gunnison, Colo.lo. KQV Doubleday -Hill Electric Co Pittshurgh, Pa. 270 KFHH Amhrose A. McCue Yeah Bay, 2 51 KQW Marls D. Harrold Ban Jae, Calif. 226 KFHL Penn College Oskaloosa, Iowa 240 KRE V. C. Battery & Electric Co Berkeley, Calif. 275 KFI E. C. Anthony. Inc. Los Angeles, Calif. 468 KSAC Kansas State Aericulturol College Manhattan, Kam. 341 KFIF Beeson Polytechnic Institute Portland. Oreg. 248 KSD Pmt Dispatch (Pulitzer Puh. Co.) St. Lout,, Mo. 545 KFIO North Central High School Spokane, Wash. 252 KSL Radio Service Carp. of Utah Salt Lake City, Utah 299 KFIQ Fiant Methodist Church Yakima, Wads. 242 KTAB Tenth Ave. Baptist Church Oakland, Cal. 216 KFIU Alaska Electric Light & Power Co Juneau, Alaska 226 KTCL American Radio Telephone Co.. Ina Seattle, Wash. 306 KFIZ Daily Commonwealth Fond du Lae, Wis. 273 KTHS New Arlington Hotel Co. Hot Springs. Ark. 375 KFJB Marshall Electrical Co. Marshalltown, Iowa 248 KTW First Prmhyterian Church Seattles Wash. 455 K FJC R. B. Fagan (Episcopal Church) Junction City. Kansas 219 KUO Examiner Printing Co Sao Francisco, Calif. 246 KFJF National Radio Manufacturing Co Oklahoma City, Okla. 252 KUOM State University of Montana Missoula, Montana 244 KFJM Liberty Theatre (E. E. Marsh) Astoria, Oreg. 252 KUPR Union Pacific Railroad Co Omaha, Neh. 270 KFJL Hardeac8 Manufacturing Co Ottumwa. Iowa 242 KWG Portable Wireless Telephone Co Stockton. Calif. 248 KFJM University of North Dakota Grand Forks, N. Dak. 280 KWKC Wilson Duncan Studios Kansan City. Mo. 236 KFJR Ashley C. Dixon & Son Stevensville. Mont. 258 KWWG City of Brownsville Brownsville, Texas 278 KFJX Iowa State Teachers College Cedar Falls. Iowa 280 KYO Electrio Shop Honolulu, Hawaii 270 KFJY Tuowall Radio Co Fort Dodge, Iowa 246 KYW Westinghoose Electric & Mfg. Co Chicago, Ill. 535 KFJZ W. E. Branch Fort Worth. Texas 254 KZM Preston D. Allen Oakland. Calif. 242 KFKA Colorado State Teachers College Greeley. Colo. 273 WAAB Valdemar Jensen New Orleans, Le. 263 KFKQ Conway Radio Laboratories (Ben H. Woodruff) Conway, Ark. 250 WAAC Tulene University New Orleans, Le. 275 KFKU The University of Kansas. Lawrence. Kans. 275 WAAD Ohio Mechanics Institute Cindunati. Ohio 248 KFKX Westinghouse Electric & Manufacturing Co Hastings, Nebr. 288 WAAF Chicago Daily Drover. Journal Chicago, Ill. 286 KFLD Pad E. Greeoùw Franklinton, Ia. 234 WAAM I. R. Nelson Co Newark. N. J. 263 KFLP Everett M. Foster Cedar Rapide, Ia. 256 WAAW Omaha Grain Enhance Omaha, Nebr. 285 KFLR L'aiversity of New Mexico Alhpauereue, New Mexico 254 WABA Lake Forest University Lake Formt, Ill. 227 KFLU Rio Grande Radio Supply Hone Ban Benito, Tessa 236 WARB Harrt,hurg Sporting Goods Co Herrt,hurg, Pa. 266 KFLV Rev. A. T. Frykman Rockford. Ill. 229 WABC Asheville Battery Co.. Inc Asheville, N. C. 254 KFLX George ROY Clough Galveston, Texas 240 WABI Bangor Railway & Electric Co Bangor. Me. 240 KFLZ Atlantic Automobile Co. Atlantic. Ia. 273 WARE. Connecticut Agricultural College Boas, Conn. 283 KFMB Christian Churches Little Rock, Ark. 254 WABO Lake Avenue Baptist Church Rochester, N. Y. 283 KFMQ University of Arkansan Fayetteville. Ark. 299 WABQ Haverford College. Radio Clnh Haverford, Pa. 261 KFMR Morningside College Sioux City, Iowa 261 WARR Scott High School, N. W. B. Foley Toledo. Ohio 270 KFMW M. G. Sateren...... Houghton. Mich. 266 WABW College of Wooster Wooster, Ohio 234 KFMX Carleton College Northfield. Mira. 336 WABX Henry B. ¡co. Mt. Clemens, Mich. 270 KFNF Henry Field Seed Co... Shenandoah, Iowa 266 WABY John Megaldi, Jr Philadelphia, Pa. 242 KFNG Wooten', Radio Shop Coldwater, Min. 254 WABZ Coliseum Place Baptist Church New Orleans. La. 263 KFNV L. A. Drake Battery and Radio Supply Shop Banta Rosa. Calif. 234 WADC Allen T. Simmons (Allen Theatre) Akron, Ohio 258 KFOA Rhodes Department Store Seattle. Wash. 454 WAFD Alpert B. Parfet Co Port Huron, Mich. 233 KFOL La1ie M. Scheibueh Marengo, Iowa 234 WAHG A. H. Grebe & Co Richmond Hill. N. Y. 315 KFON Echophons Radio Shop Long Beach, Calif. 234 WAPI Alabama Polytechnic Institute Auhuro.Ala. 248 KFOO Latter Day Saints University Salt Lake City. Utah 261 WAMD Huhhard & Co. Minneapolis. Minn. 244 KFOP Rohrer Elec. Co Marebfield, Ore. 240 W RAA Purdue University W . Lafayette. Iod. 283 K FOR David City Tire &Electric Co David City, Nebraska 226 WRAC Clemeo Agrie. College Clemson College, 8. C. 331 KFOT College Hill Radio Club Wichita. Kansas 231 WBAH The Dayton Co Mimeepolts, Minn. 417 K FOX Board of Education. Technical High &but Omaha, Nebraska 248 WRAK Pennsylvania State Police Harrisburg. Pa. 275 K FOY Beacon Radio Service St. Paul. Minn. 226 WBAO James Millilran University. Decatur, Ill. 360 KFPG Garreteon and Dennis La Angeles. Calif. 238 WBAP Worsham-Carter Publishing Co. (Star Telegram) Fort Worth, Texas 476 KFPL C. C. Baxter Dublin, Texas 242 WBAV Eroer & Hopkins Co Columhm, Ohio 292 KFPM The New Furniture Co Greenville, T. 242 WBAX John H. Stenger. Jr Wilkes- Barre, Pa. 254 KFPR L. Angela County Foreetry Dept Lea Angeles, Calif. 231 WBAY Western Electric Co New York, N. Y. 492 KFPT Cape &Johnson Salt Lake City.Utab 286 WBBG Irving Vermilye Mettapoieett, Ideas. 248 KFPW St. Johan M. E. Church Carterville, Mo. 268 WBBL Grace Covenant Prahyterian Church Richmond. Ve. 253 KFPY Symons Investment Co Spokane. Wash. 283 WRBM Atiese Investment Co Chicago, Ill. 226 KFQA The Prin'pù St. Louis, Mo. 264 WBRN Blake. A. B Wilmington, N. C. 275 KFQB The Searchlight Publishing Co Fort Worth, Texas 221 WBBP Petoskey High School Petoskey, Mich. 246 KFQC E'dd Brothers Radio Shop Taft, Calif. 258 WBBR Peoples Pulpit Asso Roseville. N. Y. 273 KFQH Radio Service Co Burlingame, Calif. 231 WBBS Church New KFQP G. S. Carson. Jr. Iowa City, Ia. 284 WBRU 3ecke Motor Sales N Monmouth, Ill. 224 KFQT Texas National Guard Dennison. Texas 252 WBBX Ruffner Junior High School Norfolk Ve. 222 KFQU W. Riker Holy City, Calif. 253 WBBY Washington Light Infantry Co. 'B 118th In/ Charleston. S. C. 268 KFQW C. F. Kderim North Bend. Wash. 248 WRCN Foster & McDoland Chicago, Ill. 266 KFQZ Taft Products Co Hollywood, Calif. 240 WBDC Bastar Laundry Co Grand Rapids. Mich. 256 K FRC City of Paria Dry Goods Ca San Francisco. Calif. 268 WRFS Blies Electrical School Takome Park. Md. 222 KFRU Ethercal Radio Co Bristow, Okla. 394 WBGA Jones Ele,. & Radio Mfg. Co. Baltimore. Md. 254 KFRW United Churches of Olympia Olympia, Wash. 220 WROQ A. H. Grebe & Co.. Inc Richmond Hill. N. Y. 236 KFRX J. Gordon Klemgard Pullman, Wash. 217 WBR Pennsylvania State Police Butler, Pa. 286 KFRZ The Electric Shop Harlington. Neh. 222 WBRC Bell Radio Corporation Birmingham. Ala. 248 KFSG Aegelw Temple Los Angeles. Calif. 272 WBRE Baltimore Radio Escheats Wilkes- Barre. Pa. 231 KFSY The Ven Blarieon Co Haleoe.Mont. 261 WBS D. W. May. Inc. Newark. N. J. 252 KFUJ Hopper Plumbing and Heating Co Breckenridge, Minn. 242 WBT Southern Radio Coop Charlotte, N. C. 275 KFUL Thomas Gogeen & Bros. Munie Co Galveston, Texas 258 WBZ Westinghouse Electric & Mfg. Co Springfield, Maas. 333 KFUM W. D. Pyle Colorado Springs. Colo. 242 W BZ& Westinghouse Electric & Mk. Co Hotel Brumwiok, Beaton. Mass. 242 KFUO Concordia Bemtnary St. Louie, Mo. 549 WCAD St. Lawrence Uoivereity Canton. N. Y. 280 KFUP Fiteeimmom General Hospital Deaver, Colo. 234 WCAE Kaufmann & Baer Co. and The Pitt burgh Pres. Pittsburgh. Pa 461 KFUQ Julius Brunton and Som Co San Francisco, Calif. 234 WCAH Eetrekin Electric Co Columbus, Ohio 286 K FUR H. W. Peery and C. Redfield Ogden, Utah 224 WCAJ Nebraska Wesleyan University University Hare, Nebr. 283 KFUS Louis L. Sherman Oakland, Calif. 233 WCAL St. Olaf College Northfield. Minn. 336 KFUT University of Utab Salt Loke City, Utah 271 WCAO Sanders & Starmau Co Baltimore. Md. 275 KFUU Colhurn Radio Lebs. San Leandro. Calif. 231 WCAP Chaapeake A Potomac Telephone Co. Washington, D. C. 468 KFUZ Y. M. C. A Virginia. Mira. 244 WCAR Alamo Radio Electric Co San Antonio, Texas 263 KFVD McWhinnie Electric Co She Pedro. Calif. 202 WCAS W. H. Dunwoody Industrial Institute Minneapolis. Minn. 280 KFVE Film Corporation of America St. Louie, Mo. 245 WCAT State College of Minos Rapid City. S. Dak. 240 KFVF Clarence B. Juneau Hollywood. Calif. 208 WCAU Durham A Co Philadelphia Pa. 278 KFVG First M. E. Church Independence, Kansas 236 WCAX Universft, of Vermont Bnrlineton, Vt. 250 KFVH Manhattan. WCAZ Carthago College Carthage. Dl. 246 Headquarters Trop. 56th Calvary Houston,utn,TTexass 248 WCBA Charles W. Heiherbm Allentown. Pa. 280 KFVN Carl E. Bagley Welcome, Minn. 227 WCBC University of Mohican Am Arbor. Mich. 280 KFVO F. M. Henry 'Orlin-ills, MD. 226 WCBD Wilbur C. Votive Zion, Ill. 344 KFVR Moonlight Ranch Route 6, Denver. Colo. 246 WCBE Uhalt Radio Co. New Orleans, La. 263 KFVS Cape Girardeau Battey Station Cape Girardeau, Mo. 224 WCBF Pad J. Miller Pittsburgh, Ps. 236 KFVY Radio Supply Co Albuquerque, N. M. 250 WCBG Howard 8. Williams (Portable) Pascagoula. Mim. 268 KFVZ Glad Tidings Tabernacle San Franck., Calif. 234 WCBH Ualverelty of Mime Oxford. M.. 242 RADIO AGE for October, 1925 The Magazine of the Hour 67 Some Real Facts About Quality Developed for Those (Continued from page 13) nently. The violin and smaller horn Who Demand theBest BATTtqy instruments carry the weight of the music. Now, with the cone speaker APEX alone, the drums come into evidence To Consumers Only with their steady beat-the chords on VERNIER DIALS Here is a real battery quality, exhaustively tested guaranteed to yon at, prices the piano, the bass violin with its are constructed on that will astound the entlre bat- and truly scientific principles and are tery-huying pnbhc. Order Di- "plunk! plunk!" and the bass saxophone. rect From Factory. Put the Neither of these represents the orchestra engineered to meet the precise re- Dealer's Profit in your own pock- quirements of experts -consequently et. Yon actually save much more fairly, yet with both speakers connected, than half, and so that you mn be these various instruments may be picked they more than meet the expectations convinced of true quality and perform- of radio user. They bring ance we give a Written 2 -Year Guaran- out individually and the effect as a whole the average tee. Hue is your protection! No need to is extremely in distant stations with alacrity and a chance. Our battery is right - aad realistic. the price is lowest ever made. Convince The lower notes can be heard to a positiveness seldom encountered and yourself. Read the prices! provide control and accuracy essen- Auto Batteries Radio Batteries considerable extent even with a trans- 6Voit,11PIate,S9.50 6VOIt,10OAmo.E9.50 former- coupled amplifier, so that these tial to full radio enjoyment. They 6Voit,13 Plate,11.50 6VOtt,120 Amp.11.50 I2Volt, 7Plate,13.00 6Yolt,140Amp.13.00I suggestions are applicable to both kinds impart a degree of elegance that cre- Buy Direct -Send No Money of audio amplifier. ates a marked improvement in the We ask no deposit. Simply send name and ad. dress and style wonted. Battery will be ehi ved Fig. 3 shows a useful method of con- appearance of any set. Clockwise and eame day we receiveyour óder Express O.B.D. necting the two loud speakers where two counter clockwise. error ea e Royal Brass Finish, 4 in. $2.00; 314 in. $1.65 each battery.. tubes are connected in parallel for the We allowut6' Satin Silver Finish. 4 in. 2.50; 314 in. 1.90 for cash in full with or- last stage of the amplifier, whether it der. Yon keel DeLuxe Gold (24K) 4 in. 3.50: 31/4 in. 2.50 Send w' orderder toda, be resistance or transformer coupled. Each speaker has to itself, so ARROW BATTERY CO. a tube APEX Dept. at. 121S So. that the distribution of output is fairly Wabash Ave..ChIcago even and the improvement is more RHEOSTAT DIALS noticeable than where the speakers are are little brothers to Apex Vernier in parallel as well as the tubes. The use Dials. Accurate. handsome -a neces- of a good power tube, is, however, sity to satisfactory operation and slightly superior to paralleling of tubes beauty of appearance. nevertheless. Royal Breen Finish ...... 5 .75 A simple loud speaker for low notes is Satin Silver Reich .85 illustrated in a rear view on page 11. Del-use Gold (24K) 1.00 6O -page It is simply an ordinary mandolin about 10 inches in diameter, having the unit Frese Reference of a Baldwin large type receiver as an actuating unit. The unit is taken out of Book its case. Fig. 5 gives a cross section of the assembly. Piece "a" is a small block of wood about 3 % inches long Quabb,Ra. oApparatus and 1 -2x1 -2 inch in cross-section. A If your dealer is unable to supply you, order y inch hole is drilled at the center for direct from us. passage of the driving pin and there are two holes for No. machine screws Apex Electric Mfg. Co. that are about 2 inches apart. This 1410 W. 59th St., Dept. 1011, CHICAGO forms the inner (clamp for the unit. The outer clamp is of similar nature, Malli long enough to fit very tightly between List the sides of the mandolin frame with a "forced fit." Thus piece "b," the outer Catalo clamp, is merely forced into position by wedging it inside the mandolin. The No.55 fingerboard is removed to permit the POLK'S REFERENCE BOOK assembly of the unit and clamps. Pieces FOR DIRECT MAIL ADVERTISERS 'Sc." 'Sc" are two long ajfg machine Shows bow to increase your business by screws for tightening the clamps. the use of Direct Mall Advertising, 60 pages full of vital business (acts and figures. Who. The driving pin may be made of a where and how many prospects you bare. long common pin with the head clipped Over 8.000 Toes of business covered. off. The diaphragm is cut out of the Write for your FREE copy. Baldwin unit and the short driving pin R. L. POLK & CO., Detroit, Mich. already in it cut and removed from the see POLK DIRECTORY BUILDING S. armature. The new pin, which should Branches In principal eitles of U. be long enough to extend from the armature to the mandolin head and allow about ji inch clearance under the inner clamp "a," is inserted, sharp point k9Ladorat'or first, in the small hole in the armature. Product CIMñ OC The point is bent around to form a hook Sell OOubleweer shoes and get all LA and it may be soldered if desired, although $2,99 you cam. No district gars to WORN wah. Tod deal direct wah us. this is not absolutely essential. A hole SHOE mplete Ilne. Wonderful values- - (sr eaamole. the rurality work shoe tocDrssttorlloulesslJmplûcation. is punched in the exact center of the shown here for 52i9ä. Our sales- big 12.000. 48.000. 50,000, 100,000 Ohms. List mandolin head, which should be stretched . ney.everywhererite for propositin. $1.50 sizes to Order S3.50 each. Dealers. write r diemte When Better Res:stanw rather tightly over the frame. If the 000BLEWEAR SHOE COMPANY ,wade they wig be Creeeenta. sheepskin is too loose, it may be tighened Oldest and LLammest Firm Selling cent Ce., S Liberty St., Jamaica, N.Y. .`. React Cru Radio Supply by tightening the clamping screws around 42 E. fate St, Minneapolis, Mim. the rim -using the key wrench made for the purpose. Fastening Pin AUDIO FREQUENCY Mailing 'Lilts the myr TRANSFORMERS win fhelp you increase suake The assembly must be carefully in- For all Hookups @@3.50 sod pei on thoaaan serted in the mandolin so that the pin All Tubes ea. eecoofvelssalaed Money Back Ñ .Uúoéi. Individ- passes through the hole in the head. Guarantee ers-ual, Professions, Boldness Cooramua. Have Your Dealer Supply Guaranteed C The frame may be sprung out of shape ( each or Order Direct 99% by refond of 5 slightly to permit the outer clamp to FLINT RADIO CO. enter and then released when the job 1892 Wilson Ave., CHICAGO is finished. The pin must not touch the Tested and Approved by RADIO AGE * 68 RADIO AGE for October, 1925 The Magazine of the Hour

WCBM Medea Swans Baltimore, Md. 229 WIAQ Chronicle Publishing Co Marion, Ind. 226 WCBN James P. Boland Ft. Bent. Harrison, Ind. 266 WIAS Home Electric Co Burlington, Iowa 283 WCBO First Baptist Church Nashville, Teno. 236 WIBA The Capital -Times Studio Madison, Wis, 236 WCBK C. H. Messier Providence, R. I. 246 WIBC L. M. Tate Poet, No.29, Veterans of Foreign Wan...St. Petersburg, Florida 222 WOBT Clark University, Collegiate Dent Worcester, Mass. 238 WIBD X.I. Radio Service Joliet, Illinois 200 WCBU Arnold Wireless Supply Co Arnold, Pa. 254 WIBG St. Paul'. Protestant Episcopal Church Elkins Park, Pa. 222 WCBX Radio Shop of Newark (Herman Lubineky) Newark, N. J. 233 WIBO Nelson Brothers Chicago, Ill. 226 WCCO Wmhburn- Crosby Co Twin Cities, Minn. 416 W1BH Elite -Radio Storm New Bedford. Maas. 209 WCEE Charles E. Erhetein. Villa Olivia near Elgin, Ili. 275 W IBl Frederick B. Zitteli, Jr Fleshing, N. Y. 219 WCLO C. E. Whitmore Camp Lake, Wisc. 231 WIBJ C. L. Carrell (Portable) Chicago, Ill. 216 WCLS H. M. Couch Joliet. Hl. 214 WIBK University of Toledo Toledo, Ohio 205 WCSH Henry P. Roes Portland, Maine 256 WIBP First Praebyterisn Church Meiridian, Mies. 210 WCTS C. T. Scherer Co Worcester. Mesa. 268 WIBQp F. M. Schmidt Ill. 205 WIBII Thurman A. WCX l Free Prece+ and Jewett Radio & Phonograph Co Detroit, Mich 516 Owings Werton, W. Va. 246 WDR J WISH New Jersey Nat'l Guard Hdm. Co. Elisabeth, N. J. 203 WDAE Tampa Deily Times Tampa, Fla.. 365 W IST Orlando Edgar Miller (Portable Station) New York, N. Y. 211 WDAF Gansas City Star Kansas City, 365 WIBU The Electric Farm Poyoette, Wis. 222 WDAE J. Laurence Martin Amarillo, Texas 393 WIBW Dr. L. L. Thu Logansport, Ind. 220 WDAR Lit Brochera Philadelphie, Pa. 393 WIBX Grid -Leak Inc Utica, N. Y. 205 WDAY Radio Corp Fargo, N. ak. 244 WIBZ Powell Electric Company Montgomery, Ala. 231 WDBB Fred ReyRaY Columbus, Gs. 236 WIE, Continental Electric Supply Co Washington, D. C. 360 WDBE A. H. Waite Co., Inc Taunton, Pa. 229 WIP Gimbel Bros. Philadelphia, Ps. 509 WDBC Kirk, Johnson & Co burg, Va. 258 WJAB American Electric Co Lincoln, Nehr. 229 WDBE Herman Edwin Buron Martinsburg, W. Va. 268 WJAD Jackson's Radio Engineering Laboratories Waco, Texas 352 WDBE Ricb.rdo n Co Atlantic. Va. 278 WJAG Norfolk Daily News Norfolk. Nebr. 283 WDBJ Wayland Eieetnc Corp Roanoke, 229 WJAK Clifford L. White Greentown, Iowa 254 WDBK M. P. Bros Cleveland, Ohio 278 WJAM D. M. Perham Cedar Rapide, Iowa 268 WDBL Dept. of Markets Stevens Point, W te. 278 WJAR The Outlet Co. (J. Samuel. & Bro.) Providence, R. I. 306 WDBN RollinsElectric Liges Power Co Bangor,r Me. 240 WJAS Pittsburgh Radio Supply Home Pittsburgh, P. 286 WDBD RdBns College. Winter lem, 240 WJAZ Chicago Radio Laboratory Chicago, Dl. 268 WDBQ Morton Radio Supply Co Salem, N.J.N. 234 WJBA D. H. Lents, Jr Joliet, Ill. 207 WDBR Tremont Boston, Mad. 256 WJBB L. W. McClurg St. Petersburg, Fla. 207 WDBV The Strand8 Theatre Fort Wayne, IDs. 258 WJBC Hummer Furniture Co LaSalle, Ill. 234 WDBX Otto Saur New York, 233 WDBD Ashland Broadcasting Committee Ashland, Wie. 233 WDBY North Shore Church Chicago, Ill. 258 WJBI Robert S. Johmoo Red Bank, New Jersey 219 WDBZ Boy tents, CityCRa Hall Kingstown, N. Y. 233 WJD Denison University Granville, Ohio 229 WDOD Dotes Radio Co.. Inc Chattanooga, Tenn. 256 WJJD Supreme Lodge, Loyal Order of Moose Moasebeart, Ill. 303 tee WilcoxWilc Flint, Inc Cranston, 271 WDWF I. Jewett Radion & Phonograph Co WDZ J. L. Bush Tortola. I. 278 WCX } and Detroit Free Prea....Pontiac , Mich. 517 WEAA F. D. Fallein Flint, Mich. 250 WJy Radio Corn. of America New York, N. Y. 455 WEAF American Telephone & Telegraph Co New York, N. Y. 485 WJZ Radio Corp. of America New York, N. Y. 455 WEAR can Wichita, Kew. 280 WKAA H. F. Paar Cedar Rapide, Iowa 278 WEAL Cornell University Ithaca, N. Y. 286 WKAR Chu. Lwoff (Crescent Park) East Providence, R. 1. 240 WEAJ University of South Dakota Vermilles, S. Dak. 283 WRAF Broadcasting Co Milwaukee, Wie. 261 WEAM Borough of North Plainfield (W. Gibson Buttfield) .. North Plainfield. N. .1. 286 W KAQ Radio Corp. of Porto Rico San Juan, P. R. 340 WEAN Shepard Co Providenm, R. I. 273 WKAR Michigan Agriculture College East Laming, Mich. 285 WEAO Ohio State University Columbus, Ohio 293 WKAV Laconia Radio Club Laconia, N. H. 254 WEAR Goodyear Tire and Rubber Co. Cleveland, Ohio 389 WKBE o is te b Webster, Massachusetts 231 WEAU Davidson Bros. Co Sioux City, Iowa 275 WKBF Dotes Wilcox Flint Cranston, Rhode Island 286 WEAY Iris Theatre (Will Horowitz, Jr.) Houston, Texas 270 WKBG C. L. Carrel. Portable Chicago, Ill. 216 WER Benwood Co St. Louis, Mo. 273 WKBK Miss Shirley Kato New York, N. Y. 210 WEBA Electric Shop Highland Park, N. J. 233 WKY Why Radio Shop Oklahoma City, Okla. 275 WEBC Walter Cecil Bridges Superior, Wis. 242 WLAG Cutting & Washington Radio Corp Minneapolis, Minn. 417 WERD Electrical Equipment and Service Co Anderson. Ind. 246 WLM. First Christian Church Tulsa, Okla. 250 WEBE Roy W. Welker Cambridge. Ohio 248 WLAP Wm. V. Jordan Louisville, Ky. 286 WEBH Edgewater Beach Hotel, Chicago Evening Post Station Chicago. Ill. 370 WLAQQ Arthur E. Shilling Kalamazoo, Mich. 283 W EBJ Third Avenue Railway Co New York, N. Y. 273 WLAX Putnam Electric Co Greencastle, Iod. 231 WERK Grand Rapids Radio Co Grand Rapids, Mich. 242 WLB University of Minnesota Minodpolie, Minn. 278 WEBM Radio Corporation of Amend Portable 226 WLBL Wieoonein State Dept. of Markets Stevenepoint, Wis. 278 wmjp E. B. Pedicord New La. 280 WLS Seso Roebuck & Co Chicago, Ill. 344 WEBT The Dayton Coop. Indmtrial High School Dayton, Ohl 270 WLTS Lane Technical High School Chicago, Ill. 258 WEBW Beloit College Beloit, Wis. 283 WLW Crm)ey Mfg. Co Cincinnati, Ohio 422 WEEI The Edison Electric Illuminating Co Boston, Mass. 475 WLWL Missionary Society of St. Paul the Apostle New York. N. Y. 288 WEHS Robert E. Hughes Evanston, Ill. 205 WMAC J. Lrdw. Page (Olive B. Meredith) Caeenovia, N.Y. 261 WEMC Berrien Springs, Mich. 285 WMAF Round Hills Radio Corp Dartmouth, Mass. 440 WENR All-American Radio Corporeton Chicago, Illinois 266 WMAK Norton Laboratories Lockport, N. Y. 273 WEW St. Louis University St. Louis, Mo. 280 WMAL Trenton Hardware Co Trenton, N. J. 256 WFAA Dallas News & Dalles Journal Dallas, Tex. 472 WMAN First Baptist Church Columbus, Ohio 286 WFAM Times Publishing Co. St. Cloud. Minn. 273 WMAQ Chicago Daily Now. Chicago, ill. 497 WFAV University of Nebraska, Department of 1 b r,. I Fogineoring. Lincoln, Nebr. 275 WMAY Kinnhighway Presbyterian Church St. Louie, Mo. 280 WFRC First Baptist Church Knoxville, Tonn. 250 WMAZ Mercer University Macon, Ga. 261 WFRD Gethsemane Reotist Church Philadelphia. Pa. 234 WMBB Trianon Ball Room Chicano, Ill. 250 WFBE Van De Walle Music and Radio Co Seymour, Ind. 226 WMBF Mimi Beach Hotel Miami Beach, Fla. 384 WFRC The Wm. F. Cable Co. Altoona. Pa. 261 WMC Commercial Appeal Memphis, Tenn. 503 WPRH Concourse Radio Corporation Now York, N. Y. 273 WMCA Hotel McAlpio (Greeley Square Hotel Co.) New York City 341 WFB3 St. John'. University Collegeville, Minn. 236 WMH Ainsworth -Gates Radio Co Cincinnati, O. 321 WFRO Wynne Radio Co. Raleigh, N. C. 255 WNAC Shepard Store, Boston, Maas. 284 WFRR Fifth Inf. Md. Nall Guard. 5th Reg. Armory Baltimore. Md. 452 WNAD University of Oklahoma Norman, Okla. 258 WFBW Ainsworth -Gates Radio Co Cincinnati. Ohio 309 WNAL Omaha Contrat High School Omaha, Nebr. 255 WFBZ Knox College Galeehmg, Ill. 254 WNAP Wittenberg College Springfield, Ohio 271 WFI Strawbridge and Clothier .....Philadelphia, Pa. 394 WKAR First Christian Church Butler, Mo. 230 WFKB Frannie K. Bridgman Chicago, Ill. 217 WNAT Lennie Brothers Co. (Frederick Leonia) Philadelphia, Pa. 254 WFUV G. Pearson Werd Springfield. Mo. 252 WNAX Dakota Radio Apparatus Co Yankton, S. Dak. 248 WFUW Earl William Lewis Moberly. Mo. 233 WNOX People, Tel. & Tel. Co. Knoxville. Tenn. 268 WGAL Lancaster Electric Supply & Construction Co Lancaster. Pa. 248 WNYC Dept. of Plant and Structures New York, N. Y. 526 WGAO Youree Hotel Shreveport, La. 252 WOAC Page Organ Co Lima, Ohio 260 WGAZ South Bend Tribune South Bend. Iod. 360 WOAE Midland College Fremont, Nebr. 280 WGRB Harry H. Carman. 217 Bedell Sc Freeport, N. Y. 244 WOAG Apollo Theatre (Belvidere Ammement Co.) Belvidere, M. 274 WCRC First Baptist Church Memphis, Tenn. 266 WOA1 Southern Equipment Co San Antonio, Texas 392 WCRF Fink Furniture Co Evansville, Iod. 217 WOAN Vaughn Conservatory of lifusie (James D. Vaughn).... Lawrenceburg, Tenn. 280 WGBG Briemnhitch's Radio Shop Thrifton. Va. 226 WOAO Lyradion Mfg. Co hll.hswaka, Tod. 369 WGBI Frank S. hleosrgee Scranton. Pa. 240 WOAR Lundskow. Henry P. Kenosha, Wù. 225 WGRK Lawrence Campbell Johnstown. Pa. 248 WOAT Boyd M. Hemp Wilmington. Del. 360 WORM Theodore N. Beaty Providence. R. I. 234 WOAV Peemmviania National Guard. 2d Battalion, I12th Infantry... Erie, Pa. 242 WGRL Elyria Radio Aeso. (Albert H. Ernst) Elyria, Ohio 227 WOAW Woodmen of the World Omaha, Nebraska 526 WGBQ Stout Institute.. Menominee, WI.. 234 WOAX Franklyn J. Wolff Trenton, N. J. 240 WGRR Marshfield Broadcasting Amn aforehfield. Wis. 229 WOC Palmer School of Chiropractic Davenport. Iowa 484 WGBS Gimbel Brothers New York. N. Y. 315 WOCC Triple Alliance Radio Station Sycamore, Illinois 205 WGRT Furman University Greenville. 8. C. 236 WOCL Hotel Jamestown, Inc Jamestown, N. Y. 275 WCRX University of Maine Orono, Mo. 252 WODA James K. O'Dea Paterson, New Jersey 203 WGES Coyne Electrical School Oak Park,Ill. 250 WO1 Iowa State College Ames, Iowa 270 WG1 American R. & R. Co Medford Hillside, Mass. 261 WOK Neutrowound Radio Mfg. Co. Homewood, III. 217 WGMU A. H. Grebe & Co., Inc., Portable Richmond Hi1L N. Y. 236 WOO John Wan.maker Philadelphia. Pa. 509 WGN The Tribune Chicago, Ill. 370 WOR L. Bemherger and Co Newark, N. J. 405 WGR Federal T. and T. Co Buffalo. N. Y. 3I9 WORD Peoples Pulpit Assn Batavia. Ill. 275 WGY General Elec. Co Schenectady, N. Y. 379 WOS Sorte Marketing Bureau Jefferson City, Mo. 440 WHA University of Wisconsin Madison, Wis. 535 WOWL Owl Battery Company New Orleans. La. 270 WHAD Marquette University and Milwaukee Journal Milwaukee, Wis. 260 WOWO Main Auto Supply Co Fort Wayne, Ind. 227 WHAG University of Cincinnati Cincinnati. Ohio 222 WPAB Pennsylvania State College State College. Pa. 283 WHAM Hafer Supply Co Joplin. Mo. 283 WPAC Donaldson Radio Co Okmulgee, Okla. 360 WHAM University of Rochester (Eastman School of Manic) Rochester. N. Y. 276 WPAJ Doolittle Radio Corp New Haven. Conn. 268 WHAP H. Alvin Simmons. 290 Flstbush Ave Brooklyn, N. Y. 240 WPAK North Dakota Agricultural College.. , Agricultural College. N. D. 283 WHAR Seaside House ktrmtic City. N. J. 275 WPAL Superior Radio & Telephone Equipment Co Columbus, Ohio 286 WH4S Courier-Journal & Louisville Time Louisville, Ky. 399 WPG The Municipality of Atlantic City Atlantic City, N. J. 300 WHAT Dr. George W. Young Minneapolis, Minn. 231 WOAA Horace A. Beale. Jr Parkersburg. Pa. 270 WHAV Wilmington Eiectrcu Specialtl Co Wilmington. Del. 360 WOAC E. B. Gish Amarillo. Texas 234 WHAZ Rensselaer Polytechnic Institute Troy, N. Y. 385 WQAE Moore Radio Newe Station (Edmund B. Moors) Springfield, Vt. 275 WHR Sweeney School Co Kans. City, Mo. 365 WOAM Electrical Equipment Co Miami, Fla. 283 WHRA C. C. Shaffer Oil City, Pa. 250 WQAN Scranton Timm - Scranton. Pe. 280 WHRR Robel's Store Stevens Point. Wis. 240 WOAO Calvary Baptist Church New York. N. Y. 260 WHRC Rev. E. P. Graham .. Canton, Ohio 245 WOJ Calumet Reinho Broadcasting Co Chicago. Dl. 447 WHRD Chas. W. Howard Bellefontaine. Ohio 222 WRAF The Radio Club (Inc.) Laporte, Ind. 224 WHRF Beardsley Specialty Company ...... Rock Island, Illinois 222 WRAK Economy Light Co Eecahana, Mich. 256 WHRG John S. Mona Harrisburg. Pa. 231 WRAM Lombard College Galesburg. Ill. 244 WHRH Culver Military Academy Culver, Iod. 222 WRAP St. Louie Radio Service Co St. Louie, Mo. 263 WHRI Lauer Auto Co Ft. Wayne, Ind. 234 WRAV Antioch College Yellow Springs. Ohio 242 WHRK Franklin Rt. Garage. Inc Ellsworth, Me. 231 WRAW Avenue Radio Shop (Horace D. Good) Reading. Pa. 238 WHRL James H. (Hussar Logansport. Ind. 220 WRAX Flaxon'e Garage Gloueeester, City N. J. 268 WHRM C. L. Carroll. Portable Station Chicago. Ill. 233 WRRC Imanuel Lutheran Church Velnaraieo, Ind. 278 WHRN First Ave. Methodist Church Rt. Petersburg. Florida 258 WRC Radio Corp. of America Washington, D. C. 468 WHRP Johnstown Automobile Co. Johnstown. Pennsylvania 256 WHRQ 8t. John's M. E. Church South Memphis, Tem. 233 WREO Reo Motor Car Co Lansing. Mich. 286 WHRR Scientific Electric & Mfg. Co.. 3664 Vine St Cincinnati. Ohio 216 WRHF Washington Radio Hospital Fund Washington. C. D. 256 W HRU Riviera Theatre and Bing's Clothing Anderson. Ind. 218 WRHM Rosedale Hospital, Inc. Minnespolie, Minn. 252 WHBW D. R. Kiensle Philadelphia, Pa. 215 WRNY Experimenter Publishing Co New York, N. Y. 258 WHRY Rt. Norbert'a College West De Pore, Wia. 250 WRK Doron Bros Hamilton. Ohio 360 WHEC Hickson Elestric Co., Inc Rochester, N. Y. 258 WPM College Schenectady, N. Y. 270 Ohio 273 Union WHK Radiovox Company Cleveland, of Hlinob, Urbana, 273 WHN George Schubert New York, N. Y. 360 WRM University Ill. WHO Bankers' Life Co Dol Moines, Ia. 526 WRMU A. H. Grebe & Co., Inc.. Motor Yacht "MU -I" New York, N. Y. 236 WHT Wrigley Building , Chicago Deerfield, DL 238 WRW Tarrytown Radio Res. Labe Tarrytown, N. Y. 273 WIAD Howard R. Miller Philadelphia, Pa. 254 WSAC Clemson Agricultural College Clemson College, S. C. 336 RADIO AGE for October, 1925 The Magazine of the Hour 69 (Continued from page 67) inner clamp or the coils in the unit. Build new type The pin is rotated, in case the soldered the phenomenal method hasn't been used, so that the bent end cannot touch the receiver radio with this amazing kit coils, or the magnets. A few drops of Everyone wants one of these revolutionary receivers that are sealing -wax on the head of the mandolin amazing engineers. You may build your own in a surprisingly and on the pin serve to complete the short time from this remarkable kit. Free book that tells how. speaker. The result is not a speaker that accentuates high notes in particular, its chief field being in the lower range. Hence, while suitable for independent operation for certain kinds of reception, its use as an accompaniment to a horn speaker is the chief consideration here. In adjustment, the position of the outer clamp depends upon the strength of the current through the windings. Moreover, the direction of current through the windings must be such that upon closing the plate circuit of the tube (as by inserting the jack) the pin will The new Erla pull (not push) upon the mandolin head. 'CircbidFiveFac- This may be felt on the head tory Bdt Kit - or may be as you receive it. seen by watching the slight movement Ready -cut, flex- of the armature in the unit. Care must ible, soldertess be taken not to leads and charts disturb the opposing nable you to spring located at the other end of the wire it in an armature. Vening. This auxiliary speaker may be located Price 549.50. underneath a table in the room, near HERE is an easy way to have the new ordinary sets with volume enough to the horn speaker and it may be con- radio that is astonishing radio fans fill an auditorium. nected either in series or in parallel with everywhere. You make a big saving and 3. Increased Selectivity. Circloids it. Both connections should be tried. have the fun of building your own set have absolutely no pickup qualities of The outer clamp should be set so that besides. their own. Only signals flowing in the no rattling occurs during reception - The amazing new inductance principle antenna circuits are built up. this being found with the proper tension found in these kits belongs to Erla alone. 4. Finer Tone Quality. The self- on the head. No other set regardless of price, can enclosed field positively prevents stray In this manner, or by supplementing offer it to you. It is based on a different feed-backs between coils. Hence no the horn loud speaker with a device kind of coil -The Erla *Balloon *Cir- blurring or distortion. Tones are crystal capable of reproducing the lower notes, cloid. Four striking advantages result: clear. the radio receiver as a whole becomes a 1. Greater Distance. Circloids have Write for free information on kit-also book more faithful repeater of what is going See how a few minutes of fun will give you the new no measurable external field to affect est and most phenomenal set known to radio science. on at the broadcasting studio. Coupled adjacent coils or wiring circuits. This Examine it at any Erla dealer's. or send the coupon with an improved audio amplifier, the makes possible higher amplification. in for full information. illustrations and diagrams contain radio set as the Home Theater comes each stage, with increased sensitivity ed in the remarkable book. "Circloid Hookups." into its intended role in full measure. and greater range. Electrical Research Laboratories. 2. More Volume. Higher r. f. am- 2500 Cottage Grove Ave.. Dept. 6-A. Chicago, U. S. A. Aiding Condenser Handling plification enables Circloids to bring Send me the new book explaining Thousands of radio fans have dis- in distant stations scarcely audible in Circloid principle and hookups. Name covered that by the simple process of DEALERS -Exclusive franchises are available to pressing on their condenser dials they high class dealers in localitiesjstill open. Write or Address wire immediately. can tune one station in and another out. City County State The majority of them do not realize that *Trade Mark Registered this is extremely bad practice, and if persisted in will ultimately ruin the bearings of the condenser. This condi- e tion only exists where the two stations are close together in frequency and are crowded on the dial settings. les, The obvious solution to this condition 5ur was early realized. It consisted of a SPEAKER tuning mechanism which would move the rotary plates of the condenser very WITH slowly over the smallest possible distance in order to get the very minute change in CONCERT capacity needed to tune the receiver to the frequency of the particular broad- UNIT casting station. This led to the many various types of * The Famous Truly Portable The Heart of the Speaker so- called "Vernier dials." The difficulty Large size and scientific construction of up to the present however has been two- TELMACO P -1 Receiver the Concert Unit gives remarkable tone Four Tubes Do the Work of Seven values which combined with the special fold; first, the use of gears in these dials amplifying properties of the BURNS The peer of portables in size, weight, ease of tuning. resulted in a certain amount of blacklash selectivity, distance, volume,workmanebip and price. horn produce wonderful results. which prevented the condenser from re- Aerial. loud speaker and batteries self contained. Complete with tribes and batteries, $1.25.00 maining in a certain position; and, second, $149.60. Receiver only the condenser design itself was not cor- P.1 Kit Saves You Money t BURNS horn is of a dis- rect for accurate tuning on the higher Our offer of the Telmaco P -1 Receiver In kit form bas tinctive design with pyralir met witb enthusiastic reception. This contains all frequencies. parts. as built by us. Including case, drilled and eu- flare in several handsome The latest type of vernier dial, known graved panel, and illustrated matroctiona. $80 00 finishes pleases the eye Complete kit -It as the Microvern, employs an extremely Ask your dealeror write us. Descriptive folder free. as well as the ear. simple mechanical principle which pro- gadio Division: duces a reduction in turning movement of five to one without the use of gears. Telephone Maintena nce Co. MAKERS The reduction ratio of five to one has 20 So. Wells St. Dept. C Chicago,111. been found good under all normal con- 7'rr`P./YCV/l C91e 'C 13'rr`y...`Y for rapid ditions, as it is fast enough State and 64th Sta., Chicago, U. S. A. station finding, and slow enough for care- Qyality 'Radio Fsclwively 'O+ Established 1918 ful final adjustment. sF Tested and Approved by RADIO AGE 0A 70 RADIO AGE for October, 1925 The Magazine of the Hour

WWGS Radio Engineeriug Coro Richmond Hill, N. Y. 213 WTG Kansas Sate Agricultural College Manhattan, Kam. 273 WSAI United States Playing Card Co Cincinnati, Ohio 325 WTIC Travelers Ineuranca Co Hartford. Conn. 323 WSAJ Grove City College Grove City, Pa. 258 WTX H. G. Baal Co Chicago, Ill. 26g WSAN Allentown Cell Publishing Co Allentown Pe. 229 WWAD Wright & Wright (Inc.) Philadelphie, Pa. 360 WSAP Seventh Day Adventist Church New York, N. Y. 263 WWAE The Alamo Ball Room Joliet. Ill. 242 WSAR naughty & Welch Electrical Co Fall River, Mass. 254 WWI Ford Motor Co .....Dearborn, Mich. 273 WSAU Camp Macienfiald Chesham, New Hampshire 229 WWJ Detroit Newa (Evening News Assn.) Detroit, Mich. 352 WSAV C. W. Viole Radio Construction Co Houston, Taxes 360 WWL Loyola University New Orleans, Le. 260 WSAY Irving Austin (Port Chester Chamber of C ,m move) ...Port Chaster. N. Y. 233 WSOE School of Engineering Milwaukee, Wis. 246 WSAZ Chas. Electric Shop Pomeroy. Ohio 258 WSRF Harda° Sales and Service Broadlanda, Ill. 233 WSBF Stlx- Baer -Fuller D. G. Co St. Louis. Mo. 275 WSTA Camp Merienfeld Cheehem, N. H. 229 WS BC World Batley Co 1219 8. Wabash Ave., Chicago, ILL. 210 WSUI State University of Iowa Iowa City, Iowa 498 WSB Atlanta Journal Atlanta, Ga. 428 WTAB Fall River Daily Herald Publishing Co Fall River, Mass. 248 WSKC World's Star Knitting Co Bay City. Mich. 261 WTAC Penn Traffic Co Johnstown. Pa. 360 WSMB Banger Amusement Co. and Maison Blanche Co New Orlaans, La. 319 WTAD Robt. E. Compton Carthage DI. 236 WSMH Shattuck Music House Owosso, Mich. 240 WTAL Toledo Radio & Electric Co Toledo. 6hlo 252 WSMK S. M. K. Radio Corp Dayton. Ohio 275 WTAP Cambridge Radio& Electric Co Cambridge. Ill. 242 WTAW Agricultural & Mechanical Callaga of Texas...... College Station, Texas 280 WTAQ 8. H. Van Gordon & Son Osseo, Wis. 220 WTAM Willard Storage Battery Co Cleveland. Ohio 390 WWGL Radio Engineering Corp Richmond Hill, N. Y. 213 WTAX Williams Hardware Co Streeter, III. 231 WTAR Reliance Electric Co Norfolk, Va. 283 WTAZ Thomas .1. McGuire Lambertville, N. J. 283 WTAS Charles E. Erbetein Elgin. Ill. 304 WTHS Flint Senior High School Flint, Mich. 218 WTAT Edison Electric Illuminating Co (portable) Boston, Maas. 240 Canadian Stations

CFAC Herald Calgary, 434 CJCA Edmonton Journal Edmonton, Alta. 511 CFCA Toronto Star Pub. & Prtg. Co. Oat. 357 CJCL A. Couture Montreal, Que. 279 CFCF Marconi Wireless Tel.. Co., (Ltd.) Canada...... Montreal, Que . 411 CJGC London Free Press London. Ont. 321 CFCH Abitibi Power & Paper Co., (Ltd.)...... Iroquois Falls. Ont. 500 CKAC La Presse Montreal, Qua. 411 CFCK Radio Supply Co ...Edmonton, Alta. 517 CKCD Vancouvar Daily Proving Vancouver, B. C. 397 CFCN W. W. Grant (Ltd.). ... Calgary, Alta. 434 CKCK Leader Pub. Co Regina, Sask. 476 CFCR Laurentide Air Service Sudbury. Ont. 410 CKCO Ottawa Radio Aseocietion Ottawa, Ont. 434 CFCT Victoria City Temple Victoria. B. C. 329 CKCX P. Burns & Co., (Ltd.) Calgary. Al.. 434 CFCU Tha Jack Elliott (Ltd.) Hamilton. Ont, 341 CKFC Firer Congregational Church Vancouver. B. C. 411 CFHC Henry Hicks & Sons Calgary, Ala. 434 CKLC Wilkinson Electric Co., (Ltd.) Calgary. Alta. 434 CFKC Thorold Radio Supply Thordd, Ont. 248 CKNC Canadian National Carbon Co, Toronto, Ont. 357 CFQC The Electric Shop (Ltd.) Saskatoon. Sask. 329 CKOC Wentworth Radio Supply Co Hamilton, Ont. 341 CFRC Queens University Kingston. Ont. 450 CKY Manitoba Tel. System Winnipeg, Man. 384 CFXC Commeastw Trust td ...... W B. C. 291 CNRA Canadian National Railways Moncton. N. B. 312 CFYC The Alb (Ltd.) Vancouver,v Calga r. B.C. 411 CN RC Canadian National Railways Calgary, Canada 434 CHBC The CagaryCalgary Albartan Calgary. Alta. 434 CN RE Canadian National Railways Edmonton, Alta. 517 CHCM Riley & McCormack (Ltd.) Calgary. Ala. 434 CNRM Canadian National Railways Montreal. P. Q. 411 CHCS The Hamilton SpectatorBic Hamilton, Ont. 341 CNRO Canadian National Railway, Ottawa, Ont. 434 CHIC Toronto Electric seeCo ...... Toronto, Ont. 357 CN RR Canadian National Railways Regina. Sask. 476 CHNC Toronto Radio sen Society .... . _Torons, Ont. 357 CN RS Canadian National Railway. Saskatoon, Sask. 329 CHUC International Bible A 'd...... Sa. 329 CNRT Canadian National Railways Toronto, Ont. 357 CHXC N. Booth. Jr. .Otrea,Ottawa, Ont. 434 CNRV Canadian National Railways Vancouver, B. C. 411 CHYC Northern Electric Co Montreal, Que. 411 CNRW Canadian National Railways Winnipeg. Mao. 384 Cuban Stations

PWX Cuban Telephone Co...... Habana 400 2K Alvara Dane ...... Rebana 200 2DW Pedro Zayas ....Habana 300 20L Julio Power ...... Habana 180 2AB . Alberto S. de Bustamante...... Habana 240 20L Oscar Collado Rebana 290 20K Mario Garcia Vet. Habana 360 Leo old Habana 210 2BY Frederick W. Borton .. ... Habana 260 Frank . E. Figueroa Cdod 360 2CX Frederick W. Gorton .. Habana 320 6K Frank H. Jones Tuinucu 340 2EV Westinghouse Elec. Co. .. Habana 220 6C Frank Hones i.n6eg 170 2114 Roberto E. Ramires .. Habana 275 60 Antonio T. Cienfiegw 170 2HC Heraldo de Cube Habana 275 6BY Eduardo TerryTerri Cienóegos 225 2LC Luis Casas Habana 250 6BY Jose GinUlli Cienfiegoe 300 2KD E. Sanchea de Fuentes Habana 350 Alerta Ullivarri Cienfiegoe 200 2MN Fausto Simon , Habana 270 8F0 Alberto Revelo Stgo. de Cuba 250 2MG Manuel G. Balas Habana 280 80 Andres .And Stgo. de Cuba 225 2JD Raul Pares Falcon Habana 105 tlDW Pedro C. Ando Stgo. de Cuba 275 European Broadcasting Stations British Stations 2L0 London 365 5NO Newcastle 400 SIT Birmingham ...... 475 5SC Glasgow 420 5WA Cardiff . 350 2BD Aberdeen 492 6BM Bournemouth 385 6SL Sheffield (relay station) 303 2ZY Manchester...... 375

French Stations YN Lyons 740 8AJ Paris 1780 FL Paris (Eiffel Tower) 2,600 ESP Paria 450

Stewart -Warner Opens a desk, which is an exact copy of the desk Mohawk Electric used by George Washington in the White Corporation Studio House. Announcements Last Saturday night, August 1, marked The furnishings, selected with great Announcement is made by the Mohawk the opening of one of Chicago's newest care, are in perfect keeping with the Electric Corporation of Chicago, that and most beautiful broadcasting studios. beautiful surroundings. The entire color they have recently completed arrange- This studio is owned and operated by the scheme blends in a most delightful man- ments with The Zinke Company of Stewart -Warner Speedometer Corpora- ner, creating an atmosphere of harmony. Chicago to sell the entire line of Mohawk tion, and is located at 1826 Diversey The studio is a departure from the Products. The Zinke Company, who Parkway. usual draped studio, which, it is said, have been established for 20 years, will The construction is of the latest and greatly adds to the comfort of the artists, maintain their policy of selling through most scientific, using a special material being cool and pleasant even in the the jobber Mohawk Receiving Sets and which does not deaden the tone of the hottest weather. Mokawk Parts. An extensive selling instrument or the voice, but retains it in The beautifully appointed reception campaign is planned for the sale of the all its naturalness and at the same time room adjoining the studio provides every Mohawk One Dial Receiving Sets. prevents any reverberations that have a convenience for the waiting artists. It is furnished with a console model, The Mohawk Electric Corporation tendency to jumble the music. announce a revision downward of prices The fine manner in which this station Stewart -Warner Matched -Unit Radio which on their line of receiving sets which have has been received all over the country reproduces the program just ONE Dial to Tune." shows the important part that the studio as it is being broadcast, providing enter- "Just construction plays in the satisfactory tainment for those who are waiting their The Model VA, now known as Model broadcasting of programs. turn to go on the air. 100 is priced at $100.00. This studio is equipped with two All programs from this station are broad- Model X is reduced from $250.00 to Baldwin special broadcast grand pianos, cast on a 226 meter wave length over Sta- $175.00, while model XII was formerly a Wurlitzer harp, a beautiful announcer's tion WBBM. sold for $300.00 now $275.00. RADIO AGE for October, 1925 The Magazine of the Hour 71 CLASSIFIED ADVERTISEMENTS If you have anything to buy or sell, don't overlook the value of RADIO AGE'S classified advertisements. Many such messages have paved the way to independent incomes. The classified advertising rates are but ten cents per word for a single insertion. Liberal discounts are allowed on three, six and twelve -time insertions, of five, fifteen and thirty per cent respectively. Unless placed through an accredited advertising agency, cash should accompany all orders. Name and address must be included at foregoing rates and no advertisement of less than ten words will be accepted. All classified ads for the November issue must be sent in by October 1.

ADVERTISING SERVICE CRYSTALS RADIO DEALERS DEALERS -Write for our illu ed catalog of reliable QUEX Sale. Letters Get More Business. Write him Supersensitive Galena Crystal.: Pound $1.00, prepaid. Radio Merchandise. Rossiter-Manning Corporation, today. Qua, 4418 Michigan Ave., Chicago. ALKEMITE. Allsensitive Crystals 50c. Buskett, Dept. D. 1830 Wilson Ave.. Chicago. Ill. Geologist, Joplin, Missouri. ENGINEERS about to begin ix- monthi research trip to territory West of the Mississippi, between Canada and RADIO SUPPLIES Mexico, are willing to consider propositions for taking HELP WANTED on radio line. on a distribution basis, with a view to WE CAN SAVE You money on radio supplies. 30 per dealers, jobber.. agent., etc., in sparsely cent discount AND MORE on tubes, batteries, loud settled districts. Such territory would be exclusively RADIO SALESMEN and SET BUILDERS-We need speakers, static eliminator.. condensers, transformers apportioned. Address all co unications confi- you and you need a If you are reliable and well German silver wire and all standard radio apparatus' dence. Only reputable lines and concerns willbe con- known in your community,. we will appoint you our W buy in quantity lots to enable selling to you whole- sidered. 100 per t distribution and advertising representative and furnish you with standard well sale. Additional discount for cash. Send for catalog representation assuredv at minimum capita t. . rive tiled sets and parts at prices that will enable you or exclusive proposition for your territory. Address, Address, Harvey s T. Kelley, Suit 301, 210 East Ohio to sell at a handsome profit. Write at once for cata- Box 9A, RADIOGRAPH LABORATORIES. 1234 Rose- Street. Chicago, Ill. log and sales plan. Waveland Radio Co., Div. 53, 1027 mont avenue, Chicago, Ill. New fall lines now reedy. N. State St., Chicago. III.

MEN wanting forest ranger, railway clerk and other SALESMEN WANTED AGENTS WANTED government position., write for free particulars of exams. Mokane, Dept. B-33. Denver, Colo. Make $100 WEEKLY in spare time. Sell what the public wants--long distance radio receiving sets. Two sales weekly pays $100 profit. No big investment, FORDS. 60 miles on one gallon of Gat. It has been no made proven can INVENTIONS sing. Sharpe of Colorado $955 in one month. Representatives wanted at o This plan to in crememlee ga. eantanteesalso prevents radiator boiling in summer or freezing in winter. Cools, Fuels, sweeping the country-write today before your Decarbonizes the Ford motor. Splendid NEW IDEAS WANTED -Well known Radio Manufac- county is gone. OZARKA, INC.. 126 West Austin Ave., territory turer whose products are nationally advertised and sold F., Chicago. open. AIRLOCK PRODUCTS, Box 703G, Willow Street. Will pay Long Beach. Calif. everywhere ante ew Radio device toe ll. outright or royaltyfor idea or invention which is really STAMPS, 50 varieties, Africa, Brazil, Peru, Cuba, n w and saleable. Address, Mr. R. F. Devine, Room Mexico, etc., 10c 50 different U. S., 25c; 1,000 mixed, Y. RADIO -Joi sales organization and make big 1101, 116 West 32nd St.. New York. N. 40c; 1.000 hinges. 10c. List free. C. Stegmen, 5950 money. Wen wants man in every county to sell well Cots Brilliants, St. Louis, Missouri. advertised sets and parts made by the leading manu- facturers. Widener of K City makes $150.00 PATENTS weekly. You can do as well or better. Write today VOCATIONS for catalog, and discounts. Name your county. Wave - U. S. and Canadian Patent on an Attach- land Radio Company, Div. 52, 1027 No. State St., Chi- FOR SALE: Make Big Money. Safe and Lock Expert. Wayne cago, Ill. ment for Phonographs; is the st beautiful inven- tion of the age. Address Chas. F. Smith, Huff, N".Dak. Strong, 3800 Lan Franco St., Lo. Angeles, Calif. MANUFACTURER'S AGENT calling on Radio-Elec- trical Jobben, Chicago and vicinity, has opening for 3 WANTED additional lines carrying volume business, as we cater PERSONAL to large jobben. Edelstein, 1804 McCormick Bid. WANTED -To mplete my set RADIO AGE need Chicago. make intereeeing August, September. October, November, 1923, Issues. LONELY HEARTS, Exchange letters, bound or unbound. Advise price. Lloyd C. Henning, new friends in our jolly club. Eva Moore, Box 908, Hollbrook. Arizona. AGENTS -WRITE FOR FREE SAMPLES. Sell Madison Jacksonville, Florida. Encloe stamp. "Better-Made" Shirt. for large manufacturer direct to wearer. No capitall experience required. Many Look! You Radio Bug! Join Radio Correspondence WIRELESS earn $100 weekly end bonus. MADISON MFGRS., 501 Club. Entirely new. Broaden your quaintance Broadway. New York. exchangeehe ge ideas. Membership open to LADY BUGS; also. Dims stamp brings pamphlet and Radio Novelty WANT TO MEMORIZE THE WIRELESS CODE? The Cards. Radio Rose, Box 662, Cleveland, Ohio. Coryden Snyder Code Method. Patented. is quickest. 90c an hour to advertim and distribute samples to con- Send 50c in stamps or M. O. to C. G. Snyder, 1423 sumer. Write quick for territory and particulars. Elmdale Ave., Chicago. Ill. American Products Co., 2130 American Building, Cin- cinnti, Ohio. PRINTING TELEGRAPHY-Morse and Wireless-taught at home in half usual time and at triding cost. Omnigraph Catalogs, Circulera. Automatic Transmitter will send, on Sounder or Buz- Man wanted for this territory to sell wonderful WE print Stationery, Booklet., : unlimited messages,ge. any specs as :xpbt value men's, s, Children's ss Press, Batavia, Ohio. just shoe. direct, Samples. Commercial oerator, would. by U 99 used y consumer leading Universities, College., Technical and Telegraph Samples supplied. Big weeklyek veperman nt Income. Schools throughout U. S. Catalog free. Omnigraph Write today Tanner. Mfg. Co., 1334C. St., Boston, Mau. RADIO Mfg. Co., 13 F Hudson St., New York. RADIO SALESMEN and SET BUILDERS in every county write Grenzer Radio, 1479 Hodiamont, St. Louie, Mo. A PRACTICAL TUBE RECEIVING SET FOR $10. WRITERS Postpaid, less phone. and tube. Complete with phone., tube and battery, $18.00. J. B. RATHBUN, 1067 Winona St., Chicago, Ill. NEW WRITERS WANTED-Articles, stories, poems, scenarios, etc. $13,500 just paid to unknown writer. Entirely w field. (No. bunk.) NOT A CORRE. "B" BATTERIES Standard soderlms radio Jacks. Binding post attach- SPONDENCE COURSE. Moving picture industry and ment.. Double c uit. One dollar bill. Postpaid. publishers crying for new original material. YOU Clinton Seward, Jr., New Peitz, New York. N. Y. CAN DO IT. We buy manuscripts for books and mag- 100 VOLT EDISON TYPE "B" BATTERY, knocked Send self addressed envelope for list of 100 down. Parts and plane-complete, $12.50. lane Mfg. sub jects. CALIFORNIA STUDIOS, P.O. Box 697, Los Three Cosmopolitan Phuslformer.. each $5.50, book of Angeles, Calif. 2937 W. Lake, Chicago. Instructions included. F. A. Mall. Tripoli, Iowa. WRITERS -Cash in on your knowledge of radio by BATTERIES FOR SALE -Four 24 -volt "Main" Storage 15 to 25 per cent discount on nationally advertised sets writing for Radio Magazines and Newspaper Supple- "B" Batteries, used, shipped and ready to wire item guaranteed. Tell Ohio. needs. ments. Write up your radio experiences, your new for $38.00. First order gets the batteries. Address IMP ERIAL RADIO OMPANY hook-up. your knowledge of broadcasting stations and Box B, Radio Age, 500 N. Dearborn St., Chicago, 111. artists. Experienced authors will correct and improve prices free. your manuscripts-make them typically professional East Liverpool, Ohio. work. FREE Criticism and Advisory Service until your ThDRado Shoppe, ox 645, manuscript is eoldl ALL Magazines and Papers de- ding fiction and articles dealing with radio. Here BUSINESS OPPORTUNITIES AT LAST The Radco Static Eliminator. Eliminates is YOUR OPPORTUNITY to profit! Send for FREE 50 to 90% Static. Many satisfied users. Write for booklet, "How You Can Sell Your Manuscripts." $100 weekly up. We want experienced Radio men to 5 rti Radio Specialties Company, Sioux Falls, Willie Arnold and Associate., 210 East Ohlo St. operate branch mbling plants. Part whole Sou h l as. Chicago, Ill. time. Barfield Radio Co.. 13 Tillery Street. Dept. A R, Brooklyn, New York. Make big money writing Movie Plays. Circulars free RADIO CIRCUITS W. C. Krug, Ashton, Illinois.

Classified ad. copy for the Novem- SPECIAL FOR OCTOBER The Reinert: Radio Booklet, by Frank D. Pearne, fully Have you ordered your ber RADIO AGE must be sent in illustrated. and RADIO AGE, for $2.50.order Price of Book - by October 1, 1925. totRADIO AGE. 500 N. Dearborn Street,, Chicago. November Radio Age? * Tested and Approved by RADIO AGE 72 RADIO AGE for October, 1925 The Magazine of the Hour The Far West Gets Its Radio Thrill THE RADIO AGE Far back in the days of the gold rush in Nevada- Tuscarora, became one of the most prominent settlements in this vast area of the unexplored western frontier. BUYERS' SERVICE The bright metal manifested itself in What do you want to purchase in the radio line? Let the staff of RADIO AGE gave you greater quantities and with less difficulty time and money by sending in the coupon below. Eater the number of the article you to obtain than in almost any section would like to know more about in the space, provided in the coupon. during these feverish days of prospect- ing, and many 1 "A' Batteries 95 Grid leak holders 186 Rheostats, automatic brought back wealth 2 Aerial protectors 96 Grid, transmitting leaks 187 Rheostats, battery which can be traced today to represent 3 Aerial instal 197 Grid leaks tube 188 Rheostats, dial 4 Aerials 98 Grid leaks, variable 189 Rheostats, filament the beginning of some of America's 5 Aerials, loop 99 Grinders, electric 190 Rheostat., potentiometer wealthiest families. 6 Amplifiers 100 Ground clamps 191 Rheostats, power 7 Amplifying unit. 101 Ground rods 192 Rheostats, vernier No greater excitement and common 8 Ammeters 102 Handles, switcb 193 Rods, ground law ruled a community more true to the 9 B batteries 103 Head bands 194 Rotors 10 Batteries (state voltage) 104 Head phones 195 Scrapers, wire wildest days of the western frontier, than 11 Batteries. dry cell 105 Head sets 196 Screwdrivers 12 Batteries storage 106 Honeycomb coil adapters 197 Screws picturesque Tuscarora -and, these same 13 Battery chargers 107 Hook ups 198 Schools, radio old surroundings stand today as then, 14 Battery clips 108 Horns, composition 199 Seta, receiving-cabinet 15 Battery plates 109 Horns, fibre 200 Seta, receiving -crystal except for its quiet populace -doubtless 16 Batter) substitutes 110 Homs, mache 201 Sets, receiving- knock- the fringe of pioneers "gold 17 Bezel Ill Home, metal down of those 18 Binding post. 112 Home, wooden 202 Sete, receiving - Neutro- days" who had passed down from one 19 Binding poets, insulated 113 Hydrometers dyne generation 20 Books 114 Indicators, polarity 203 Sete, receiving -portable to another. 204 Sets, receiving-radioe fre- 21 Boxe., battery 115 Inductances, C. W. \VJAZ -The Zenith portable broad- 22 Boxes, grounding 116 Insulation, molded quency 23 Bridge wheatetone 117 Insulation material eta, ing -reflex casting truck, touring to the western 206 Sets, receiving- regenera- 24 Broadcasting equipment 118 Insulators, aerial coast on experimental broadcasting in 25 Bushings 119 Insulators, composition tive 26 Buzzers 120 Insulators, fibre 207 Sets, r ing- Reinartz locations which have baffled radio engi- 121 Insulators, high voltage 208 Sets, receiving-sectional 27 Cabinets 209 Sets, receiving- shortwave neers, after having experimented in 28 Cabinet., battery 122 Insulators, cloth 123 Insulators, glass 210 Sets, receiving-super-re- 29 Cabinets, loud speaker generative broadcasting from Pike's Peak, began 30 Carbons, batten 124 Insulators, hard rubber 125 Insulators, porcelain 211 Sets, transmitting their long journey to Nevada and over 31 Cat whiskers 212 Slate 32 Code practisers 126 Irons, soldering the Rockies when they stopped at Tus- 127 Jacks 213 Shellac 33 Coils 214 Sliders 34 Coils, choke 128 Filament control carora. Very few Tuscarorans have ever 129 Jars, 215 Socket adapters 35 Coils, coupling battery 216 Sockets. had the opportunity to see much of this 36 Coils, filter 130 Keys, transmitting 217 Solder 37 Coils, grid 131 Knobs 218 Soldering irons. electric day's modern invention, and as R'JAZ's 38 Coils, honeycomb 132 Knock -down panel units 219 Soldering pasta radio transmitting apparatus, mounted 39 Coils, inductance 133 Laboratories, testing 220 Solder flux 40 Coil., Reinert. on a motor 134 Lever. switch 221 Solder salts truck stopped for the day - 41 Coils, stabilizer 135 Lightning a 222 Solder solution Tuscarora awakened from its peaceful 42 Coils. tuning 136 Loosecouplers 223 Spaghetti tubing 43 Condenser parts 137 Loud speakers 224 Spark coils daily routine and again "came out" 44 Condenser plates 138 Loud speaker unite 225 Spark gaps 45 Condensers, antenna coup- 139 Lug., battery 226 Stamping with that same excitement and gala ling 140 Lugs, terminal 227 Stators front as of those bygone days. 46 Condensers, by -pas 141 Measuring instruments 228 Stop points 47 Condensers, coupling 142 Megobmeters 229 Switch Placer miner Lee \\'ah, one of the few 48 Condensers, filter 143 Meters, A. C. 230 Switch I remaining Chinamen of the 1500 Chinese 49 Condensers, fixed (paper, 144 Meters, D. C. 231 Switch points grid, or phone) 145 Mica 232 Switch stops laborers brought to Tuscarora more 50 Condensers, variable grid 146 slice sheets 233 Switches, aerial 65 51 Condensers, variable mica 147 Milliammeters 234 Switches, b than years ago to build the Central 52 Condenser., vernier 148 Mineral. 235 Switches, filament Pacific Railway, after much explanation 53 Contact points 149 Molded insulation 236 Switches, ground 54 Contacts, switch ISO Molybdenum 237 Switches, inductance and assurances, finally appeared before 55 Cord tips 151 Mountings. coil 238 Switches, panel the "Mike" with his original Chinese 56 Cords, for head seta 152 Mountings, condenser 239 Switches, single and dou- 57 Couplers, loose leak ble throw cymbals, gong and drums which are over 58 Couplers, molded 153 Mountings, end 240 Tone wheels selections 59 Couplers, verio 154 Mounting., grid leek 241 Towers, aerial 100 years old and rendered 60 Crystal alloy 155 Mounting.. honeycomb 242 Transformers, audio fre- which the \VJAZ portable station broad- 61 Crystal holders Mcoil quency 62 Crystals, rough 156 ounting.. inductance 243 Transformers. filament cast on the air to the public far out and 63 Crystals, mineral switch 244 Transformer., modulation beyond. 64 Crystals, synthetic 157 Nameplates 245 Transformers, power 65 Crystals, unmounted 158 Neutrodyne sat parts 246 Transformers, push -pull Lee \Vah displayed suspicious toler- 66 Crystals, mounted 159 Nuts 247 Transformers, radio fro-. 67 Desks, radio 160 Ohm ance while performing before the micro- 68 Detector unit 161 Oscillators 248 Trans ormers, variable phone, to 69 Detector, cry etal 162 Panel cutting and drilling 249 Tr itcers believing the entire procedure 70 Detectors, fixed crystal 163 Panels, drilled and un- 250 Tubes va c -peanut be a huge joke, and fell in with the occa- 71 Dial, adj drilled 251 Tubes, vacuum -two ele- 72 Dials, composition 164 Panels, fibra ment sion as purely a matter of humor and to 73 Dials, hard rubber 16S Panels, hard rubber 252 Tubes, vacuum -three ele- 74 Dials, rheostat 166 Parts ment be a good fellow. But when the camera- 75 Dials, metal 167 Paste. soldering 251 Tuners 76 Dials, vernier 168 Patent attorneys 254 Variocoupler, bard rubber man pointed their outfits his way, Lee 77 Dials with knobs t69 Phone connector., multi - 255 ariocoupler, molded \Vah in for cover. The 78 Dies 256 eriomuplers, wooden ran great panic 79 Drills, electric 170 Phonograph adapters 257 Variom , hard rubber bull's eye lenses to the Chinaman, were 80 Dry cells 171 Plates, condenser 258 Variometers, molded 81 Earth grounds 172 Plugs, coil 259 Varn rs, wooden no different from any regulation frontier 82 Electrolyte 173 Plugs, telephone 260 Varnish,h, nsulating 83 174 Pointers, dial and knob 261 Voltmeters 45 Colt's pistol of the days when Lee, 84 Enamels, metal 175 Poles, aerial 262 Washers End stops 176 Potentiometers 263 Wave meters (with all of the early settlers), came in to 86 Eyelets 177 Punching machines 264 Wave traps make his stipend as a laundryman. 87 Experimental work 178 Reinert. set parts 265 Wire, aerial 88 Fibre sheet, vulcanized 179 Regenerative set parts 266 Wire,rbreided and stranded 89 Filter reactor.; 180 Receiver caps 267 Wire, copper 90 Fixtures 181 Rectifiers, battery 268 Wire, Insulated 91 Fuse cut outs 182 Resistance leaks 269 Wire, Litt 92 Fuses, tube 183 Resistance units 270 Wire, magnet Neat Pliers Made by 93 Generator,high frequency 184 Rheostat bases 271 Wine, platinum 94 Grid choppers, rote, 185 Rheostat strip. 272 Wire. tungsten Schollhorn i-as s e es satoesasssss as RADIO AGE BUYERS' SERVICE, 600 N. Dearborn St., Chicago, Ill. A very handy and effective radio plier 1 Please see that I am supplied with buying specifications an I prices on the articles numbered herewith: is made by The William Schollhorn Company, New Haven, Conn. The pliers

I I I steel, very strong I I I I I I I I I I I I 1 are made of stamped I and sturdy. They are specially suitable I am a- D Dealer U Jobber Mfgrs.' Rep. Manufacturer 1 for turning eyelets of various sizes in bus I Firm [If identified with Radio industry] bar wire. Between the jaws just above I the square recess is a flat vise -like surface My Occupation _ 1 to be used to flatten out the eyelet been turned. Below the 1 My Nana ._._.---_._..._._. after it has recess is a sharp pair of bus bar cutters. 1 Address,_.._.._....-._-._.._. ._._..__._.- .._. -. These pliers have the advantage of being 1 to afford a good grip with- I City large enough ^ State out being excessively heavy. I;i s s m s s s s sis s s s p m m t s ae p s a, a, o a' o, sm e as p m s s - AGE x * Tested and Approved by RADIO .._.._. Hookups That Will Always Be Up -To -Date!

What You Get : You may try to save money on radio parts - you may content yourself with a mediocre, care- The RADIO AGE lessly- planned radio set, but after all is said and ANNUAL for 1925 is done and the results given the acid test, you will brim full of hookups find there is no substitute for a good radio and "how- to- do -it" hookup. articles. In addition to the array of con- In choosing the hookup for your needs this structional set arti- Fall -the set that will penetrate the strong cles, you will find in- stations and bring in pleasing and clear DX, you structions for build- must get the absolute best or you will regret ing wave traps, bat- your choice in the end, when you will be forced tery chargers, am- to dismantle the "just -as- good" hookup and plifiers, loud speak- make the real thing. ers, etc. And to top The RADIO AGE ANNUAL for 1925 contains it all you'll find the nothing but tested hookups; circuits that have big 32 -page blue- emerged with flying colors from the most strin- print section con- gent tests radio engineers could impose. The taining the prize ANNUAL does not contain a hookup that will hookups for 1924 and not please you in every way and be just as good a 1925! Real blue - year now as is prints to work by! from it today. Each blueprint is Before beginning your new radio season, get worth the cost of the ANNUAL for 1925 and take your pick. You the book! 120 pages can't go wrong. Only a few hundred ANNUALS of features in all! left, at a dollar a copy. Get yours now! $1.00 a RADIO AGE ANNUAL $1.00 a Copy FOR 1925 Copy Some of the Features 'low to read and understand hookups. feedback receivers, neutrodynes, re:lex hookups, Baby Het No. Ilow to understand radio phenomena. 2, a Wonder Super -Het, and others. Building your first simple set. How to get rid of interference. I low 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 -heterodyne for the super experimenters. Making a reflex set. super Building Hints on tracing troubles in super -heterodyne circuits. your first Reinartz set. A The renowned Baby Heterodyne No. 1. three-tube long distance regenerator. Adding audio and radio stages to the Baby !let. A 3 -tube set that easily receives KGO on the loud speaker I low to make a battery charger. from Ohio. How to make a loud speaker. Improving the ever popular Reinartz. RADIO AGE ANNUAL BLUEPRINT SECTION with auch AND MANY OTHER UP-TO- THE -MINUTE HOOKUPS AND popular hookups as the aperiodic variometer, loop s ets, ARTICLES.

RADIO AGE ANNUAL COUPON RADIO AGE, INC., 500 North Dearborn St., Chicago, III. Gentlemen: I want to be a proud owner of 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 i Lo_om._.,_.,M,,e.._.._.,.ur,,.,..,,..,0..,,...,,_,,,,,,10 -23 ACIS CJOOCI cis Zenith" «T WANT a radio set which will 1 give me the same true quality of tone -the same selectivity - the same volume without distor- tion - the same long distance range as Zenith." That is the ex- pressed desire of thousands and thousands of radio enthusiasts. The reason for their ambition is simply this: Zenith radio sets are never offered to the public until all laboratory experiments have been carried to a satisfactory con- elusion -until in side -by -side tests with other radio sets Zenith suprem- acy has been completely demon - stra ted. Zenith radio sets will never be produced on a quantity basis at the sacrifice of quality. But -which is better: to be dis- tinguished merely for volume of production -or to be distinguished for a degree of excellence so high that it sets the standard through- Super- Zeniths are priced at from $240 to $2,000. out the industry? Ask your nearest Each instrument is sold under a quality guarantee. Zenith dealer for a demonstration. Above is shown the De Luxe Italian remodel. ZENITH RADIO CORPORATION Straus Building, Chicago

Again Commander Donald B. MacMillan has chosen Zenith exclusively for his expedition to the Arctic. When human lives may de- 1TH pend upon the reliability of radio performance, only one reason can explain his choice: Zenith has proved to be the best obtainable, LONG - TRADEDIS t N - at any price. MARK REG. RAD 1 O Costs More - but Does More!

* Tested and Approved by RADIO AGE