Jute Maga3ine O the Hour Dio If'od Q

AUGVST 1924-

Jute Maga3ine o the Hour WITH WHICH 1S COMBINED dio if'oDQ

In This Issue

Why Two Sets of Same Circuit Produce Different Results. Experiments in Radio Movies. Breaking Into Radio Without a Diagram. Broadcasting by Repeat - ing-A New Era in Radio. Theory of the New Eng- lish "ilnidyne." Weird Bogies of the Ether. Filtered Audio Stages for Super- Heterodyne. Some Fortunes and Rep- utations Radio Has Made. How French Scientists Are Eliminating Static.

J Let OurHooIcups BeyourG \. AN HATTAN ELECTRICAL SUPPLY CO..JNC. MAKERS OF THE FAMOUS

N 4TTAN 1D SPEAKER AND

RED SEAL PHONOGRAPH ATTACHMENT Oldest and Largest Distributors of RadiçjCooatjon of America

114 SO. WELLS ST., CHICAGO NEW YORK ST. LOUIS SAN FRANCISCO RADIO AGE for A ugust, 1924 The Magazine of the Four 1 flow lAverage X12 a Day in RADIO WORK By Howard Houston

Mr. Crosby, I'll have the set there that wasn't "YES, overcrowded? Where Yinstalled tonight... yes, all ready could an ambitious to 'listen -in' ... sure you'll be able to fellow stand a good get Washington by 9 o'clock." chance to earn big Another hour and a half job! And money and getahead? Stenographers, ac- another ten dollar bill in my pocket! countants, clerks - It all seems like a dream. But let all down the line - lee tell you the whole story f rom the every well established very start. line of work was overcrowded, and the pay was small. few ago, I driving a A months was Then Mary said, bread wagon, selling bread to retail "Why not find a new stores. I had a good route though, field?" That was a and if I do say so myself, I had built good thought. The But try men who went into up a pretty good business. the railroad business as I could, thirty -five dollars a week early "cleaned up." was all I could make that job pay. The sane was true I'd be working there now if it of the movie game, been for Mary. We'd been the automobile busi- hadn't ness -but what was "keeping company" for about two the coming field? years, and everything was all set for What new develop- our getting married as "soon as I ment was there that would be earning more money. But looked like a new promising industry? Easy to Learn Radio at Home the old job didn't hold out much We both jumped to our feet. "RADIO." in Spare Time promise -and I didn't see how I was Just a word about this Radio business. Why hadn't we thought of it before? All Some fellows think you've got to have some qualified for any other work that around would pay more. us was the evidence of the tremen- training before you start to learn Radio. dous development of Radio. The broad- That's bunk. I didn't know the difference It was Mary who gave me the tip. casting stations sprouting up all around - between an amplifier and a doorknob before "You can't earn big money," she the rapid increase in Radio Stores -new I started. But let me give you a tip. Don't a radio manufacturing plants - everybody experiment with your radio course. Get the said, "unless you're some kind of talking about the latest radio program. of best. The National Radio Institute has been specialist. Learn some line work Radio had captured America almost over- teaching Radio ever since 1914. The govern- -become an expert in it." But what night -and thousands of men who were on ment recognizes its course by allowing business, profession or trade was their toes were due to make fortunes out of credits to its graduates when they are trying it. for a license, so you see you can be confident Pay you're getting the best training possible - Increases Thousands of Men Needed and that means a lot. Over $100 a Month The very next day after I had finished my I am averaging anywhere from route, I went to several radio business firms. Send for Free Book S75 to $150 a month more than I there "RICH REWARDS IN RADIO" was making before enrolling with "Sure, was an opening. Oh, they'd you. I would not consider $10,000 pay big money -but did you know Radio ?" Incidentally, the National Radio Institute too much for the course. That was my cue. Learn Radio. Become publish a mighty interesting book on Radio. (signed) A. N. Long, a Radio Expert-and I did! They send it out without cost to anyone who 121 No. Main St., wants to It is filled with Well, that really is my whole story. I've learn about Radio. Greensburg, Pa. only followed the least facts, photos, and figures on the Radio In- started. I've path of all resistance. Sort of built up a business of dustry, and tells about its course which Doubles Salary my own installing, building, and repairing quickly prepares you right at home in spare 1 can very easily make double radio sets. Any small job pays me least time for one of the big pay positions in Radio. the amount of money now than at Take my advice and Mary's send before I enrolled with you. Your $5 -and usually $10. I can easily make -and course has benefited me approxi- for that, no matter how little you know of from $50 to $100 a week more as I mately $3,000 over and above -and Radio, or what your plans are. Just mail what j would have earned had I get my work systematized. not taken it. T. Winder, the coupon for it now. Address the National 731 Bedford Ave.. What Mary and I have got to decide after Radio Institute, Dept. 53HA, Washington, Grand ,junction, Colo. our honeymoon -oh, yes, we are soon hav- D. C. ing a very quiet wedding -what we must From $15.00 to $80.00 a Week deckle after that -is which end of Radio I NATIONAL RADIO INSTITUTES, - will he best. You see, there of Dept. 53HA, Washington. D. C. Before I you I are dozens enrolled with Please send without obligation was making a week on n different kinds of work in this field, it's so me cost or your Sly Free Book "Rich Rewards in Radio," which tells farm. Now, I earn from $2.080 to big. I've already had several offers -one all about in Radio, and how S4,420 a year and the work is a the opportunities to take charge of a radio department, an- spare time study at home will qualify me for a hundred times easier than before. paying radio Also Since a little a other with a broadcasting big position. full details on graduating over station, another your Free Employment Service. ( year ago, I have earned almost to give radio entertainments, and a good $4,000 and I believe the course will be worth at least S100,000 offer as superintendent of construction in a Name Age.... to me. radio plant. What we want to decide on is (Signed) George A. Adams, which will not only pay the most money now Address Route 1, Box 10, but will lead to the most rapid advancement Tamaqua, Pa. City State 1 in the future. - Always .11errlirui RADIO AGE Il'hes Writing to Advertisers 2 RADIO AGE for August, 1924 The !Magazine of the flour

0 a ODQ gaff A Chat With the Editor The Magazine of the Hour Established March, 1922 HE most modest- appearing WITH WHICH IS COMBINED departments of a magazine like RADIO AGE usually are the most valued in the minds of the qddi1opcs readers. This was especially evi- dent recently, when M. C. Rrilliams, Volume 3 ' AUGUST, 1924 Number 8 of Rantoul. Ill., wrote us he received 1,180 letters within ten days after the June RADIO AGE ap- CONTENTS peared on the news- stands, because of Page the publication of one of his hookups in the "Pickups" section. The Invisible Circuit 7. Just 1,180 readers By Frank D. Pearne thought enoumlt of Mr. Williams' How Soon Have Radio Movies short Will We ' article to write him immediately By S. R. Winters and ask for more information. We Breaking Into Radio \Without a Diagram 1 I have yet to learn the total number By Brainard Foote of readers who have communicated Broadcasting by Repeating -A New Era 1: pith Mr. Williams since the Tune The New English 4- Element Tube Circuit 1, issue. By John B. Rathbun To augment RADIO AGE'S Weird Bogies of the Ether 1q powerful influence over followers By Carl H. Butlnan of the latest and best in radio de- Filtered Audio Stages for Heterodyne 21 velopment, we are continuing our Radio is No Longer "Seasonable" 25 policy of keeping the "fans" in- By Robert J. Casey formed on the most recent discov- Some Fortunes and Reputations Radio Has Made eries and theories in the scientific -and Other Studio -Land Features 24 -29 field. In this issue, which has not An Audio Amplifier Without an A Battery 30 been decreased one iota in interest By Brainard Foote because of the presence of Summer - Radio in Other Lands 32 time, especial attention is paid to now Radio on the Farm 35 plans under way for circum- navigating the globe with radio. Radiotorials .37 Last month we started a series Pickups and Hookups by Our Readers 38 on this subject by delving into the With Radio Manufacturers 44 and 64 mysteries of short wave transmis- New and Novel Radio Patents 46 sign and reception. This saine Buyers' and Sellers' Data Sheets 49, 50 subject is taken up again in the following pages to show how world - Radio Age Technical Data Sheets 54, 56 \vide co- operation of radio stations Corrected List of Broadcasting Stations 58 will enable the fan in Cleveland to tune in on a broadcast from Berlin Radio Age is published monthly by whenever his fancy desires. RADIO AGE, Inc. The foregoing is just a sample of Advertising, Editorial and Publication Offices, ' what is offered to RADIO AGE 500 N. Dearborn St., Chicago readers every month in our tech - FREDERICK A. SMITII. Editor nical columns alone. This careful RUSSELL H. HOPKINS, Associate Editar selection of editorial content has FRANK D. PEARNE. Technical Editor made FELIX ANDERSON, Technical Assistant RADIO AGE a by-wordy for Louis L. LEVY, Circulation Manager reliability, and old and new readers M. B. SMITH, Business Manager are assured this steady improve - Advertising Manager nient will be carried on more in- HARRY A. ACKERBURG tensively than ever in the Septem- ber number -which, by the way, Eastern Representatives has a "surprise" feature that will DAVIDSON & HEVEY 17 West 42nd Street, New York City revolutionize the radio magazine Telephone, Longacre 1698 field. On the stands about Aug. 26. Advertis)ng forms close on the 5th of the month I preceding elate of issue . \p licants for membership in A. B. C. %,g Issued monthly. Vol. 3. No. S. Subscription price. $2.50 a year. / Eater as s nd -class matter April 4, 1924. at the post office I Chicago. Illinois. under the act of March 3. 1579. j -Editor, RADIO AGE pyright, 1924, by RADIO AGE, Inc. RADIO AGE for August, 1924 The Magazine of the Flour 3

_-_=- --- - Device found Oll

C i eceiVo r

EBE QDI TRADE MARK for REG PAT - U.5 OFF "Hair's breadth" Dial adjustments

"1 % 7HEN the archer misses V V the center of the target a- he seeks for the cause of his failure within himself." The Grebe Tangent Wheel Vernier

-Confucius To HAVE once experienced the ease with which you can tune in stations on a Grebe Receiver, is to know the value of the The man who owns a Grebe Tangent Wheel Vernier. Receiver seldom misses, for theTangent Wheel Vernier The keenest appreciation comes, however, enables him to acquire ex- when you find yourself instinctively reaching treme accuracy in for this ingenious little device below each of the tuning dials on some neighbor's receiver. tcrm' V .[. This and many other details of Grebe crafts- manship are fully covered by patents granted and pending. These details are sought by the man who looks inside of the cabinet.

Let us tell you more «bout grebe Receivers Grebe Regenerative Receivers are licensed under Armstrong U.S. A. H. GREBE & CO., INc. Pat. 1,111,149. No. - Oct. 6, 1914. Van Wyck Blvd. Richmond Hill, N.Y. Western Branch; 451 E. 3rd St.. Los Angeles, Cal.

always .11eution RADIO AGE Ii'heN Writing to Advertisers 4 RADIO AGE for August, 1924 The Magazine of the ¡four

America's Best Known Amateur

Fotograms. Harry H. Carman, of Freeport, L. I., or, technically speaking "2EL," is called the country's best known amateur radio broadcaster. He has been heard in Eng- land, France, San Francisco, and other distant points. He has received cards from all over the country acknowledging reception of his station. He is shown above in his broadcasting room seated at his apparatus. Ciliti'Lns SEP 15124 RADIO AGE for August, 1924 The Magazine of the hour la! 101 poi

á A Monthly Publicatio, á M. B. Smith Devoted to Practica! Frederick A. Smith T Business Manager Radio Editor OI IDI IDL I01 iOI loi IDI IDI ID[ I01 10001 101 I01= The Invisible Circuit By FRANK D. PEARNE

IN THE construction of radio sets it erator as far as ten feet from the field. very often happens that the same A Novel Explanation of At a distance of six feet, a small piece of kind of a circuit assembled by two very thin iron pointed toward it at just the different individuals will not give the same Jinx That Often Causes right angle may be made to support small quality of reception. They look alike, nails and tacks, by the stray lines which contain the same apparatus and to all Two Sets of Same Circuit are collected and concentrated in this appearances they are the same, but one way. Naturally the magnetic field set up works better than the other. to Function Differently in the neighborhood of such coils as are Where is the jinx that selects some poor used in radio receiving sets never reaches hard working fan as the object of his anywhere near the strength of the field attention? Why is it that one set will lines arrange themselves somewhat as of a generator, but it must also be remem- work better than another. when they are shown. It will be seen that some of the bered that a radio receiver is about the apparently just the same? The answer is lines never even get far enough out to most sensitive piece of apparatus known that there is so much going on inside of reach the second coil, while some of them and extremely weak magnetic fields will a receiving set that the eye does not see travel out for some considerable distance have a very noticeable effect upon them. and, in fact, the circuit itself is such a from their source, often going far enough It is not very difficult to realize how to cut through other coils used in other very small part of the set, that the builder very little we know about the invisible . does not realize what is going on in the parts of the set, which they are not intended magnetic field which is ever surrounding invisible circuit. The "invisible circuits" to cut through. When this occurs, then, the different parts of the set. Our troubles in a receiving set are those formed by currents are set up which cause iinterfer- do not stop here, either, for there is magnetic and electrostatic fields which ence; and these currents are due to unde- another invisible force at work which de- are set up by the rapidly oscillating cur- sired magnetic coupling. In this type of stroys much of the energy which really rents flowing through the different parts coil there are many lines produced by the ought to be harnessed and made to do used in it ; and in most cases little or no coil which are not utilized, and many of useful work. This is the electrostatic attention is paid to them. More trouble them will cause interference. field to which many losses in the receiv- and dissatisfaction are caused by these Now, by referring to Figure 3, we find ing set may be directly traced. Electro- magnetic and electrostatic couplings than another type of coil. This is of the honey- static losses are always present where from any other source, although many comb or spider web variety and it is not currents of high frequencies are employed radio enthusiasts do not even know that hard to see that in such an arrangement and the places where they may occur are they exist. the magnetic circuit is concentrated in a many indeed. very small space. In this case, nearly all How many of us have tried the old FIRST of all, let us consider the mag- of the lines get out far enough to do useful experiment of rubbing the glass, or hard netic field which is produced in and work, but do not travel far enough to rubber rod with a silk handkerchief 'and around the coils used. Figure 1 shows the cause interference with other coils. Con - seeing it attract small tissue paper pieces lines set up in one turn of wire through sequently there is much less loss from just as a magnet attracts a piece of iron? which a current is flowing. This pictures stray fields than will be found in coils Did you ever at the time stop to consider the lines in a small way and represents shaped like that in Figure. 1. how much energy was used up in rubbing the two sides of the loop through which Let us suppose, for example, that we the dielectric, compared to the small the current travels. The rapidly oscillat- have two radio receiving sets which are amount of work which was required to ing current makes these lines whirl about apparently just alike, but some of the lift the small pieces of paper? Well, at the conductor, first in one direction and parts are not located in exactly the same any rate, it is not the most efficient then the other, their direction changing position. In one case an offending stray means of transferring energy from one with each alternation of the current. If magnetic force may reach just far enough form to another. Insulation such as hard another coil which is in no way connected to cause interference in another part of rubber is absolutely necessary in the con- to the first one is placed close to it, these the set, while in the other case the parts struction of a radio set and it makes won- invisible lines of force cut through it. and are so located that they cannot quite reach derful insulators, but it also saps the in doing so will produce a current in this the danger line. How are we to know energy away from the places where it is second coil which will have the same char- how far apart these parts may be located needed most. We do not. however, rub acteristics as the current in the first coil with safety? This is a question, indeed, the insulators or insulating materials Any inductively coupled circuit operates and one which only may be answered by with silk in the radio set, but the high upon this principle. The most unfortu- experience and past performances of a frequency currents which are used do nate part of it is that these lines do not similar nature. One is very much sur- practically the same thing. confine themselves to just cutting through prised to find how far these magnetic the turns of the second coil, but if the fields will sometimes stray. IN ORDER that we may understand coil happens to be of the type shown in just what a dielectric material is, let Figure 2, consisting of many turns wound IT IS possible to find stray lines of force us refer to the variable condenser. Here side by side on an insulating tube, the from the field of a direct current gen- we have two sets of metal plates which 6 RADIO AGE for August, 1924 The Magazine of the Hour

\ I / / somewhere, and the only energy coming -, -----` N s into the receiving set is from the \` trans- I Ì / \ />/s(- s-.. \ / / - - \ mitting station, so it is not very hard to \ I i N see that when the high frequency / /' / , \ \\ /r' \ currents .- \\\ ------\ act upon insulating bodies in a receiving / / \ I t// \ \ set, much of the energy which should be / \\\\\I I/ / \ \ \ \ \ giving up useful work is entirely wasted / / /'.------1 t, / / ' \ and lost so far as reception is concerned. \\ \ Therefore the reception is materially / i / ' _; '-= . weakened. li 7 / \ \ \\1 \\I Just where do these losses occur? In the I Il t/ \ \ I //i tlÌi/ I`\`/-\ first place, most of the coils in used radio I I 1 ' li ¡¡I i uÌ 11 ,i j work today are wound upon insulating I t 1 1 \ 1 - // / tubes and as these tubes come under the \ \ \ \ `:\ // ////, ///I11 11 \ ' -,// `:__-/ influence of the electrostatic field set up N -- \\ l l in the coils by the rapidly oscillating cur- \ \ \ \ \ \ %/ 1/ l¡ \\ \ ' / / / / \ \ // //it, l \ __, / rents, all the energy used in swinging the - / \ forth is wasted molecules back and energy --- t \ / \ \ \ _-- _ '/ / / 1\\\\ \ / which is supplied by the very feeble cur- \ / // 1 t \ \ ' / / \ 1\ / / rent received upon the aerial. It may be \ I \ `-- / // readily is I i // understood that there not very \\ \` _- ' / \`\\ ---- /,/ /7 / much energy to do the required work, to \ ` / / 1 \ i \ say nothing of throwing most of it away \ / / 1 - `- l . I , . -- ./ in useless work. How. then, may this loss be a founda- Magnetic field between conductors. eliminated? Some kind of tiori or support must be used to hold the are separated by air. Air is, of course, versed, then they are all swung around so turns of wire in place. If these coils could an insulator and in this case is the dielec- that they point in the other direction. As be made self-supporting, our troubles tric between the plates. Now let us set the direction of the position of these mole- from this source would be over, but this the movable plates in a certain position cules is changed with each reversal of cur- seems an impossibility. The efficiency of and notice the capacity. If thin sheets of rent, it may be easily understood that the a coil having only an air core would cer- mica are placed between the plates, it will more rapid the oscillations, the faster these tainly be a valuable asset to the radio be found that, although the plates are still molecules will move back and forth and receiver. The nearest thing to perfection in the same position and the same dis- also that considerable energy is required is the honeycomb and the spider web tance apart, the capacity of the condenser to move them at this high rate of speed. coil. This type of coil is wound in a zig- has been considerably increased. The rea- When the rapidly oscillating current is zag manner in such a way that it is self- son for this is the fact that the dielectric passed into a condenser, the plates receive supporting and at the same time the turns constant of mica is much higher than that a charge, first in one direction and then are widely separated, which is another of air. But what does this all mean? The in the other. great advantage. ordinary definition of the word dielectric Let us analyze this coil before going would be "a non -conductor of electricity." ACH charge so received on the plates, any farther and see just what can be Some of these non -conductors are better FJ however, is retained for a fraction of gained by using it instead of the long type insulators than others. In all cases they a second and at the next reversal of with many turns spread out over the sur- have the property of absorbing electrical the impressed current this charge travels face of an insulating tube. Referring energy under certain conditions and they with it with its energy added to it, so again to Figure 3, we find that the wind- also have what is known as specific induc- that the energy used in charging the plates ings are concentrated within a very small tive capacity, which means "ability to is not all wasted, but in many other cases space. This, as previously explained, convey the influence of an electrified where insulating materials are used, this keeps the magnetic field within bounds so body." energy which is absorbed is absolutely lost that it is not scattered all through the The dielectric constant of air is taken so far as radio reception is concerned. other apparatus and at the same time the as unity and the dielectric capacity value The energy consumed in moving these coil is small and takes up less space than of other substances are reckoned from molecules back and forth must come from the one which is wound on a tube. this value. When a rapidly oscillating current is passed through a condenser, the plates are first charged in one direction and then the other as the current oscil- lates. This produces a strain on the dielectric material between the plates and these lines of strain may be made visible by sprinkling finely powdered mica around and about the plates and the insulating material between them. Figure 4 shows how a map of the electrostatic field between two oppositely charged conductors would look. It will be noticed that these lines of strain are at right angles to the magnetic lines of force and Figure 5 shows the combination of both the magnetic and electrostatic fields around two wires of a circuit. When an insulating material is under the influence of a rapidly oscillating current, it absorbs energy which seems to be caused by the molecules of the material moving back and forth with each reversal of the current. When the current passes through in one direction. the molecules all are forced around so that they point in the same direction. When the current is re- Magnetic lines produced by current passing through a coil wound on a tube. RADIO AGE for August, 1924 The Magazine of the flour 7

T 1S self -supporting, as it has no tube in the center to hold the turns together. Another thing in its favor is the fact that the turns are so arranged that there is considerable space between them. Here we have another advantage not yet mentioned. In any coil where the turns are close together there exists what is known as distributed capacity. That is, one turn acts like a plate of a condenser with reference to the turns close to it and the more turns the coil 'contains, the higher will be the distributed capacity. The effect of this capacity when added up means that here again much energy is lost. as it is the same as though a high resistance is connected across the terminals of the coil, through which much of the energy supposed to be passed to other parts of the circuit leaks away. Many radio engineers recommend a method of reducing this distributed capacity in long coils consisting of a single FiG 3 layer. This is accomplished by winding a piece of cord beside the wire and after Magnetic lines produced by honeycomb. or spiderweb coil. the coil is completed, the twine is removed, leaving a coil in which the turns are separated far enough to reduce the capacity to quite an extent. But in the honeycomb and spider web windings we find that the particular form of winding gives to the turns even a greater separa- tion than the twine method, and we also have the benefit of the advantages before mentioned. There is one very important point to remember in the construction of such coils, and that is not to make them too small in diameter, as this will have a tendency to crowd too many lines through the center and over -saturate the air space within the coil. Naturally, the smaller the coil. the smaller will be the opening in the middle, and if the lines become too crowded in this space, then the nice circles shown in Figure 3 are very much distorted and are forced out farther than they would be if the air core were not saturated. Thus it would seem that the use of this type of coil would eliminate many of the troubles so common to the radio receiver Electric field between oppositely charged conductors. and also serve to unravel the mystery of why one set should work better than another. 1C/6, 1r Ailk IIII Dry Cell Standards Under Way Representatives of nine dry battery #411. manufacturers, four electric companies, rAtilfr two telephone companies, a railroad, the American Railway Association, and nine Pr en* 441 Government departments met at the Bureau of Standards recently at a pre- Olt:: OMNI, Al. liminary conference on dry cell standardization. Standard performance tests 01P-41iiiilnaltAllei for radio filament and plate batteries were adopted at the conference, and the standardization of B battery sizes. or at least a standardization of the unit cells, was proposed. A special sub -committee will shortly be appointed by Dr. G. W. Vinal of the Bureau of Standards to make rec- ommendations as to the B battery specifications. The committee decided not to require a "noise" test of batteries since they were $ì2JJpI/10v.. not believed responsible for sufficient noises to make such tests worth while. A sketch showing the electric and magnetic fields around two. wires of a circuit. 8 RADIO AGE for August, 1924 The Magazine of the Hour Short Wave Transmission and Its A Handy Wireless Chart Recent Phenomena 300 .1000

THE development of short wave radio sistently in Los Angeles with loud speaker transmission, which has resulted in the strength on only two tubes, and this at rebroadcasting of American signals by times when daylight covered the Western eight English stations, has produced some half of the country. Tests have shown interesting phenomena. As high as ten that the signals are remarkably free from kilowatts have been impressed on one an- fading, which is experienced on the longer S00 tenna in starting the 107 meter pulsations wave lengths. on their long journey and, because of this Novel Sets Used great power, special precautions must be 400 While the design of a short wave trans- taken by those who handle it. 700 For months mitter is similar to that of any broadcast- 1 experiments have been car- 11J ried on by a group of General Electric ing set, the enormously high frequency tn involved radio engineers in a small isolated build- -2,803 kilocycles- requires the W ing, a mile from the transmitter of WGY. use of some unusual and novel apparatus. J Í1_I The is In this building has been assembled, in antenna of the fan type, but it dif- the apparent disorder of most labora- fers in some respects from the conven- 500 6o0 tional antenna. In order to decrease tories, the equipment necessary for a high - powered radio transmitter. The station, resistance losses its conductors are made of -eighth which because of the power and variety of wave three inch hemp, over is braided fine of bare copper lengths used, operates on the experimental many strands license of the General Electric Company, wire. The two wooden poles supporting 2NI. the antenna are much larger than neces- 5°O sary to support a structure of this size 600 Because of the intense field about the _..1 but they are essential to prevent the an- transmitter it is possible to light an ordi- from nary sixty-watt lamp full brilliancy by tenna swinging. to The building sheltering the transmitter W holding the lamp in the hand. Two men, is located a short distance to one side, al- standing on insulated stools, and each W700 lowing the counterpoise to come directly holding a metal rod in his hand, can draw underneath center of antenna. and a six-inch arc between the rods. No shock the the greatly increase the radiating efficiency 4-00 is felt because current of this nature The is feet skin rather than of the system. antenna eighty travels through the feet in width ui Boo through the body. However, if bare hands high and sixty at the top part of the fan. It has a fundamental were used instead of the metal rods, a of 160 meters. IL severe burn would be the result. The The oscillating system is of the conven- building is heated by a small coal stove tional coupled -type in which the fre- 900 and the engineers have learned that care from quency is controlled by a tuned circuit must be taken in transferring coal This the stove. If the body rather than the antenna circuit. the coal bucket to eliminates the possibility of frequency in contact with any metallic object. I000 o comes change due to the swinging of the antenna arcs will jump from stove to shovel. in the wind. The primary coil consists of Precautions Necessary one and one -half turns of copper ribbon oc. two inches wide tuned by an air condenser o DIetal pencils, watches or similar feet a articles containing metal cannot be car- made of aluminum plates three square. In solving the problem of a r on account of the small t200 ried on the person spacer for these plates that would not which will jump to them. Shoes li sparks break down, the use of very thin hard with nails cannot be worn because of the Power when the wearer steps rubber strips was decided upon. sting experienced tubes are of the water- cooled type and are on nails in the floor. mr connected through a pump to a large radi- By the use of its short wave transmit- water reached distant places with ator which insures an uninterrupted ter, WGY has supply. < a fair degree of reliability which were only 1500 ZOO- occasionally reached on long wave lengths. Modulator Tube Cooled HZ The signals are also transmitted so clearly The modulator tube is water -cooled and and with such volume that it is possible it is connected to the same cooling system to rebroadcast them 3,000 miles away. On as the oscillator. The speech power am- 250 and, be- d several occasions all eight stations of the plifier is a -watt radiotron, o British Broadcasting Company relayed cause of the intense field from the oscil- u WGY's broadcast programs. The most lator and its associated apparatus, it is successful experiment was that of April 5 shielded by a copper box to prevent re- when an entire program of organ, tenor generation and the resulting loss in qual- and trumpet solos and an address, was ity. All wires connected to the amplifier 20Q0 J- -- IstJ carried by wire from the Wanamaker are shielded and the lines to the studio B auditorium in New York to the transmit- and control room are covered with lead A signal ter of WGY in Schenectady. and are buried to prevent the radio Here is à chart that will be found useful for This entire program was sent out on 107 from getting back into the input circuit. quickly converting kilocycles into wave lengths water - or vice versa. meters and also on 380 meters. and the The plate power supply to the If the frequency is known, find it in Column signals on the former wave length were cooled tubes is a three phase, full wave A and look across to Column B. where it is in- - stantly converted into wave lengths. picked up and relayed by the British sta- rectifier capable of supplying thirty kilo For example. if the frequency is 1.500 kilo- tions. According to a radiogram received watts at fifteen thousand volts. Filaments cycles, what is the wave length? Find the ma- 1,500 in Column A. Directly opposite it in from London during the progress of the are lighted by special direct current Column B is 200 meters-the wave length. program the transmission was: "All as chines to eliminate the ripple which results Again, if the wave length in meters is 300. what is the frequency? Find the 300 in Column clear as if played in London." The short from the use of alternating current on B and directly across in Column A the answer wave signals have also been heard con- tubes employing a high filament current. is found to he 1.000 kilocycles RADIO AGE for August, 1924 The Magazine of the Hour 9 How Soon Will We Have Radio Movies? By S. R. WINTERS

,t ROM our easy chairs by the fire - the picture surface to the bottom as the r1H side we stay -at -homes will soon be prismatic ring rotates. By the same token, Experiments by Noted able to view the bleak ice fields as the identical ray of light passing through the broadcasting lens is carried over the Inventor Show Radio a second prismatic ring, with its diameter North Pole in that great ship, the Shen- set at right angles to the first, will em- andoah." Entering Magic Realm brace the picture surface from left to Thus spoke C. Francis Jenkins of Wash- right. If, then, one of the prismatic ington, D. C., as he contemplated the of Visual Broadcasting rings is rotated one hundred times faster possibilities of the transmission and recep- than the other, it is seen that the picture tion of motion pictures by radio. He had frequency lamp stationed immediately in surface would be covered horizontally in just completed the apparatus for accom- front of them. In the path between the one hundred parallel stripes by the plishing this epochal achievement, and the conventional radio -transmitting apparatus pointed beam of light. photograph illustrating this article is the and the revolving prisms is a light sensi- "But have you never put a nickel under first one showing this mechanism. tive cell, for instance, a Case Thalafide a piece of paper and by drawing straight The inventor claims that only refine- cell, through which the fluctuating electric lines across it with a very dull pencil made ments in this apparatus are necessary be- currents are given passage before being a picture of the Indian appear ?" inquired fore a football game played in Philadelphia put on the air by the transmitter. The Mr. Jenkins in reducing the process to a may be witnessed in San Francisco. principle involved, in general, is that simple analogy. Already moving objects -the movements electromagnetic waves are susceptible to "Well, now, that isn't so very different of a hand, for instance, have been sent the impression of picture characteristics from the way we do it. In place of the from one point to another in the labor- just as electrical waves may be translated crayon pencil we draw lines across the atories of Mr. Jenkins. The extension and into speed if voice characteristics are im- white surface with a pencil of light, the application of this demonstrated experi- pressed thereon. ifnage of light being the source of high ment, in accordance with theory, would intensity and high frequency. seem to bring within the realm of accom- How Rays of Light Work "When the machine (referring to the plishment the flashing on the screen of an THE new optical shape in glass makes glass discs) is turned over slowly, this event transpiring at some distant place. possible the transmission of photo- little light looks for all the world like a For instance, the President of the United graphs and ultimately motion pictures by tiny twinkling star as it travels across the States in exchanging greetings with the radio. The warped contour of this ring white surface in adjacent parallel lines, Premier of France could look upon the of transparent substance, when rotated changing in light values to correspond in light countenance of the latter, or vice versa. across a beam of light from this high - position and intensity to the values Similarly, the chiefs of staff of our Navy frequency lamp, produces an effect on the of the scenes before the lens at the broad- and Army could view at headquarters all latter comparable to that of a glass prism casting station. that the lens records as it is carried aloft which changes the angle between its faces. A Magic Picture in scouting aircraft. Or, putting it differently, there is a con- c c D UT when the machine speeded up Not So Complicated stant change in its retracting angle. l until the succession of lines recur rj1HE mechanical units for the sending The effect on a ray of light passing with a frequency that deceives the eye. through this glass ring, having a fixed because of persistence of vision into the 11 and receiving of motion pictures by radio, as apparent in the accompanying axis on one side of the latter, is to give belief that it sees all these lines all the photograph, are not as complicated as one . to the ray of light on the other side of time, then a picture suddenly flashes out would think. The essential parts consist the glass prism an oscillation or hinged on the white screen in all the glory of the of a glass prism and another glass disc action in the plane of its diameter. Con- pantomime mystery." which contains a plurality of lens ele- sequently, a ray of light passing through The equipment for the reception of ments. Immediately in front of these this prism and spending its force on a pic- photographs and motion pictures by radio prismatic rings is an electric lamp, simi- ture surface at the top will travel across duplicates the units used in their trans- lar to the light bulbs in homes, and an C. Francis Jenkins, of Washington, D. C., is electric motor for rotating the prismatic shown below with his invention for broadcast- rings. Light from this high -frequency ing motion pictures by radio. The essential lamp shines through the large number of parts are very simple, consisting of a glass lens prisms or holes in one of the discs as prism and a glass disc containing a plurality of it revolves, fluctuating in value in order lens elements. The accompanying article tells to make the moving pictures on the screen. hcw it's done. The entire apparatus may be enclosed in a small box. The transmission and reception of photographs by radio is already an accomplished fact -this feat being daily demonstrated over a distance of seven miles, and in one instance, pictures have been sent and received between Wash- ington and Philadelphia, a distance of 135 miles. The principle applied in the transmission of "still" pictures and motion pictures differs only with respect to speed. Demonstrations in sending photographs have required thrèe minutes for completing the process, whereas, the sending of moving objects involves a speed of sixteen pictures a second. - The prismatic lenses or revolving prisms serve the purpose of cutting up the light rays as they emanate from the high- 10 RADIO AGE for August, 1924 The Magazine of the Hour mission. The modulated electromagnetic Fifteen Million Homes to until the small hours of the early morning waves, arriving at the receiving station, to get distance still further increase the are translated from electrical characteris- Have Radios drain on your lighting supply mains. tics to picture characterist;cs by means of Atlantic City, N. J. -"The many tech- another pair of prismatic rings and a light nical improvements in the art of broad- A 75 Million Increase valve or lamp. The latter unit, which is casting and in the manufacture of receiv- "At the present rate of progress in the now subject to refinements in order to ing apparatus during the past year have radio industry, it will not be long before transmit motion pictures over distances, given such impetus to the development of radio will add $75,000,000 yearly to the may be filled with carbon bisulphide and the radio industry in the United States aggregate income of the Central Station the tube is wound with wire somewhat that radio now occupies a leading place industry. while daily it becomes more con- similar to the winding formation of the in American life," David Sarnoff, vice - venient and economical for the public. tuning coil used in radio telephony and president and general manager of the "It is more than a mere prediction to telegraphy. The electric waves as they Radio Corporation of America. declared say that 10,000,000 radio receivers will be come into the receiving station light and recently in an address before the annual in operation within the next five years. extinguish this small lamp thousands of convention of the National Electric Light My understanding is that the lighting in- times a second-with such rapidity, in Association. dustry serves approximately 10,000.000 fact. that the human eye is deceived in "Present indications point to two meth- wired homes. with an expected annual in- believing that the light is burning con- ods of operating radio receivers in the crease of 1,000,000 homes per year. stantly without fluctuations. Once the future," he said. "These might be classed as fol'ows: "At the end of five years you would light rays pass through the prism lenses supply electricity to at least 15,000,000 at the receiving station, the picture sent homes and we might safely predict that out by the broadcasting station is auto- at least one -half of these wired homes matically reproduced on a screen. will be equipped with radio." "The whole apparatus," to quote the inventor, "is comparable to a camera with a lens in Washington and its photographic Amateurs Help Station plate in San Francisco; with this difference, that the one lens, in Washington, Dartmouth, Nova Scotia.-Frustrated may put its picture on ten, one hundred in his attempt to get a "repeat" on an or one thousand photographic plates in important European news article by a as many different cities at the same time, sudden break in the trans -Atlantic cables. and at distances limited only by the radio the operator of the local radio receiving power of the broadcasting station. station, maintained by several American newspapers, called on amateur radio men "With this new apparatus wireless dis- to help him resume his schedule with the tribution of news pictures for daily paper British transmitting station. As the sta- illustration insures the distribution of pic- tion is equipped for receiving purposes ture news as promptly as telegraphic only, the operators are seriously handi- news; which means that pictures of news capped whenever the reception is, broken events get into the daily papers as early and a "repeat" is desired. as telegraphic text. It means just exactly In such cases they make a practice .of that, and it takes no particular imagina- calling upon the cable companies to for- tion to visualize the value of such service mard requests that the transmitting sta- to the newspapers. tion resume schedule at the place where the break occurred. On this occasion, it cc T IS even more than this, for these T n as impossible to get even this help. 1 radio news pictures projected from The screens of operator of the British transmitting magic lantern slides on to the station, unaware of the difficulty, con- best picture theaters in the cities, the tinued to send. In about an hour and a to news events enable the theater put half the schedule it news- would be over and before the public sooner than the would be impossible to get the particular distribute telegraphic Kadel & Herbert papers can print and HERE'S A NEW ONE. portion of the item that had been lost. news; that is, the daily paper is now When you tire of that old phonograph The local receiving operator communi- threatened with second place as a means record, don't throw it away or let it col- of news distribution, for no newspaper cated with Major William C. Borrett, lect dust on the shelf. Follow Rudolph operator of Canadian amateur station, can possibly put a distant news event of an or- Arnold's novel scheme using 1DD, and manager of the Maritime divi- before the public as quickly as the theater dinary 12 -inch phonograph record as a can with radio pictures." panel for a one -tube receiving set. He sion of the American Radio Relay League. Major Borrett asked several Halifax and is most rapid means reports more than satisfactory results. Photography the Dartmouth amateurs to listen on short radio is the swiftest of copying and waves and, if a European amateur was Francis Jenkins. means of intelligence. C. The Future of Radio heard, request him to have the British inventor of the motion picture projecting "Type 1 -The home receiver that will operator repeat. machine universally used in theaters. draw its vacuum tube energy through claims to have wedded the two. Half an hour was consumed in listen- such a current supply device operated ing but, as no European amateurs were is the term he employs, "Radio vision" from the lighting circuit now supplied by heard, the operators of 1BQ and 1DD from the telescope in that and it differs the Central Station. decided to send out a "general call" in latter covers great distances only by the "Type 2 -The rural home receiver, or the hope that some listener in England which lead off following straight lines the portable receiver that obtains operat- would pick it up. The call was kept up into space. Radio vision, on the other ing power from storage or dry batteries." for fifteen minutes; then another fifteen see along curved lines, hand, is enabled to many contacts which were spent in listening. and, mountains and other com- Discussing the therefore, made with other industries, Mr. mon obstructions do not mar the view. radio has Finally they received a telephone mes- contemplates the Sarnoff pointed out that radio already has sage that they had been successful. The In fact, Mr. Jenkins situ- President of the United affected the electric light and power superintendent of the transatlantic re- time when the United States. States may look upon the face of the ation in the ceiving station was heard saying "Thanks, King of England as he talks with him; "More people," he said, "now stay at you have put it over all right. We are and radio vision around the globe is not, home to enjoy radio, which means more getting our repeat." A British amateur according to this distinguished inventor, use of lights and greater current con- had heard the message and informed the beyond the realm of future possibility. sumption. Radio enthusiasts who stay up operator of the transmitting station. RADIO AGE for August, 1924 The Jlagazine of the Hour 11 Breaking Into Radio Without a Diagram A Simple Receiver Which Will Work Without Outside Wires By BRAINARD FOOTE

ARE YOU afraid of "diagrams," of One porcelain tube socket (7). binding posts. "Skin" the insulation off "hookups ?" Do you hesitate to One 6 -ohm filament rheostat (8). the ends with a knife and use pliers or a join the radio game because you One 1% -volt dry cell (12). wrench to tighten the binding posts have heard that you can't work a radio One variometer (10). securely. The wiring list is as follows, and set costing less than $150 on anything but One 22Y2-volt "B" battery (11). you should check it against the photograph an outside aerial? Did you realize that One board about 8 by 18 inches. as you make each joint : you can assemble your own receiving set Other parts not in Fig. 1 are: from a mere photograph without previous One WD12 detector tube. Post "A" to left side condenser "1." radio experience of any kind and at a One 25 -turn honeycomb or Coto-Coil. Right side of condenser "1" to right cost of about $25 all told? You can. One 75 -turn honeycomb or Coto-Coil. side mounting "2." Even if your landlord won't let you Oie telephone head set. Left side mounting "2" to post "G." hang wires on his roof, you are already lb, of bell wire for connections. (These connections finish the "pri- provided with an aerial in the form of One separable plug for connection to mary" circuit.) your electric lighting wires, your telephone lighting socket. Rotary plates of variable condenser line and your door -bell wiring. Of course, Two small spring clips for making "4" to left side mounting "3." I don't mean to imply that such a method contact to radiator, etc. Left side mounting "3" to socket "7" of receiving will bring in stations from Dials for condenser and variometer if post marked "F +." across the continent, but it will work well not furnished with them. Right side mounting "3" to left side up to 25 or 30 miles, and if you have grid condenser "5." a broadcasting station in your own town, Even though the grid condenser you Fixed plates variable condenser "4" to you are well equipped. No doubt the purchase doesn't look just like the one left side grid leak "6." simple set illustrated is not the hand- illustrated, it will have two binding posts Left side grid leak "6" to left side somest model in the world, but its chief which are connected in circuit as in Fig. 1. grid condenser "5." merits lie in its simple construction and This, in fact, is true of the variometer and Right side grid condenser "5" to equally simple operation. And you don't the variable condenser. Don't get the socket "7" post marked "G." have to buy instruments which look ex- very cheapest in each line and you'll be Right side grid leak "6" to right side actly like those shown to secure success- rewarded with better results and more grid condenser "5." ful results either, but, nevertheless, the durability. (These connections form the "secon- pictures will tell you how to make the The first part of your program is to dary" circuit.) i connections. mount the instruments on the board after Socket "7" post marked "F -" to left the fashion of Fig. 1. They will all be What You'll Need side rheostat "8." easy to screw in place except the vari- Right side rheostat "8" to outer post Identification marks after the parts ometer and the condenser. These may be of dry cell "12." listed below appear in Fig. 1. fastened down with small brass brackets Socket "7" post marked "F to cen- such hardware removing +" as stores carry, ter post of dry cell "12." Four spring clips or binding posts one of the mounting screws of the inform the "fila- (A, G, T). strument and using it as a holding post (These connections Two .002 mfds. fixed condenser for the bracket. The batteries may merely ment" circuit.) (1) (9). be stood in position. The socket is Socket "7" post marked "P" to left Two single honeycomb coil mount- mounted with the slot toward the left. post of variometer "10." ings (2, 2). Right side of variometer "10" to front One 17 -plate variable condenser (4). The Wiring post "T." One fixed or variable grid condenser Lengths of the bell wire are cut off to Rear post "T" to right side (plus) (5). make the connections. The pieces should post of "B" battery "11." One 2- megohm grid leak and mount- be slightly longer than necessary to allow Left post (negative) of "B" battery ing (6). enough for bending the end around the "11" to socket "7" marked "F +."

THE SET ASSEMBLED Figure 2. The completed model with tubes and honeycomb coils in place. The left -hand dial tunes in the stations while the right -hand controls the loudness. 12 RADIO AGE for August, 1924 The Magazine of the flour

NO DIAGRAM NEEDED Figure 1. This is your wiring diagram, and it should be checked with the list of connections given in the text. Tech- nically, this is a "Tuned Plate Regenerator."

Right side variometer "10" to front Way in between the fixed plates. Then spring clip connectors to an end of each. side fixed condenser "9." turn the variometer slowly. At a certain One wire should run from the "G" post Rear side fixed condenser "9" to left point yoù will hear a click, and then you of the set to the radiator or pipe. If the side (negative) of "B" battery will find that if you place your finger on radiator is employed. just clip on to the "11." the left post of the variometer a click is nickel plated outlet valve or to the screw (These connections complete the heard. As you take your finger off. an- of the control handle. Be very careful "plate" circuit.) other click is heard. When your set is so when you connect to the phone, for the adjusted that you hear a click when you wire must not touch anything but the "A" After the connecting wires have been place your finger on that binding post and post of the set. Condenser "1" prevents put in and carefully checked up, you are hear another one as you take it off, the any interference with the phone conversa- ready to learn something about the prin- tube is actually a low power transmitting tions, but permits radio currents to pass ciples upon which the set operates. Con- or sending outfit. Were the aerial and through the coil of the primary circuit. nect the phone cord terminals to posts ground wires connected, the set would send Attach the clip to the nickel plated screw "T." insert honeycomb coil of 25 turns out disturbing noises and might interfere hich fastens the microphone to the stand. into mounting "2" and the 75 -turn coil with reception by some neighbor within into mounting "3." Then set the rheo- a few blocks. Hence you should be care- Other Aerials stat to the "Off" position, where the con- ful not to allow your set to transmit any You should try your set in connection tacting blade does not touch the wires of more than you can help. Your tube is said with some other antenna system, too. Of the little coil but rests upon the fiber. to be "oscillating" when it is in the send- course. if you have the space for an out- Next insert the tube into the socket, han- ing condition. However, the most sensi- door wire, erect one by all means -a well - dling it carefully, as it is valuable and deli- tive point is found just below the actual insulated antenna of about 100 feet direct cate. Turn on the rheostat slowly until oscillation. so when turning the variom- length will do very well. The wires of you can see a faint cherry red glow in the eter, get as close as you can to that point the doorbell system always operate with center of the tube, showing that current without actually allowing the tube to send. considerable success as an aerial, and con- from the battery is passing through the The sensitive condition is indicated by a nection to them may be made by attaching "filament" circuit and illuminating the sort of breathing sound. the clip connecting to the "A" post to tube. Now you will find that if you increase either binding post of the doorbell. Where At this juncture, you should hear a the "capacity" of the variable condenser the electric light wires are elevated on bell -like ringing note when you touch the by turning the movable plates further in poles in the street, or in a building con- tube or the table, and if you do not, it is between the fixed plates you will have to taining a large amount of wiring, the light- a sign that something is wrong with the move the variometer to again locate the ing wires sometimes form a better aerial plate circuit or with the telephones. These "clicking" point. You will find that you than the phone line. Remove the spring can be tested quickly by touching their can follow the condenser up and down the clip from the "A" wire and attach, in- terminals to the posts of the dry cell, scale by. readjusting the variometer. stead. one post of the separable socket where a loud click should be heard if they Next turn off the rheostat. If you have plug. Insert the plug in a suitable lamp are O. K. Verify the plus and negative a telephone in your house, this makes the sócket, turning the switch "on" and trying connectins to the "B" battery. best receiving aerial. Lo /ate the receiv- a reversal of the plug to make contact ing set near the phone and at the same to the side of the line which works the Getting Oscillation time near a cold water pipe or the radiator. better. As in the case of the phone, the Now set the condenser "4" at about Cut two lengths of the bell wire about the condenser "1" insulates the set from the half scale. or with the rotary plates half correct size and fasten one of the extra (Continued on page 611 RADIO AGE for August, 1924 The Magazine of the Hour 13 Broadcasting by Repeating Will Enable Radio to Encircle Globe

HP. DAVIS, vice -president of the organization will be operated somewhat Westinghouse Electric and Davis Predicts Advent in the manner of the great news agencies Manufacturing Company, uni- of today, and will continually be on the versally known as the "Father of Broad- of Super- Station Chain search for interesting programs from casting," has made public a plan for every point in the world. world -wide programs combining all the "A famous statesman -a world -wide modern engineering achievements of radio desired. These transmitters will not need figure of interest -is speaking in Paris. transmitting and forecasting the marvel- any more power than have the leading He faces the microphone which leads to ous development radio will make in the stations of the United States today. The the station located at one of the central next few years. inaudible transmitters, however, may be broadcasters. This central station sends The plan Mr. Davis proposes makes highly powered to give them the ability out his speech on the audible wave which use of radio repeating, eliminates inter- when necessary to maintain a constant can be heard on the ordinary receiver ference possibilities and shows how, in range. As their signals will be trans- operated in the district surrounding Paris. the near future, the radio listener will be mitted on the inaudible wave length, the Then, if desired, the inaudible wave enabled to hear programs from London, power used will not cause interference transmitter also sends out the speech for Paris, Tokio, in fact any part of the globe, with receivers. world -wide transmitting. with the same ease as programs from local "The despatchers have selected the stations are now heard. New Stations Needed route for transmitting the `booster' sta- The plan shows a marvelous vision for "There will be located, at advantageous tions who by prearrangement pick up the the future of radio and indicates how points, inaudible wave length repeating inaudible wave coming from Paris. These radio will eliminate time and distance. stations whose sole duty it will be to stations will then `boost' the inaudible In detail it follows: receive these inaudible waves from the Paris wave so that anywhere in the world, "In the past few months the public has central stations and pass them along. as has previously been determined, it may heard much regarding radio repeating These repeating stations will act as be received on the short wave receivers without realizing, perhaps, just what this `booster' stations to amplify over and over of the local broadcasting stations. extraordinary achievement of radio engi- again the inaudible signals. "In Pittsburgh, KDKA, being equipped neering means to the future of radio. If "Certain other stations, and there may with a short wave receiver, could pick up the public knew that when the first radio be as many of these as desired, will be these repeated short wave Paris signals repeating was successfully accomplished, equipped with short wave receivers with and repeat them through its own trans- the entire course of future radio develop- which it Is possible to pick up the short mitter with the result that everyone ment has been changed and the practically wave signals and repeat them on a low within the range of KDKA's signals could unlimited possibilities of radio broadcast- power audible wave. These stations, which hear the Paris speech with receiving appa- ing had at last been opened, it would have are to serve local districts only, will ratus no more sensitive than is required given the idea even more attention than merely repeat the signals caught on the to pick up the broadcasts originating in was granted when it was announced. low wave length and rebroadcast them KDKA's studio. for the benefit of the listeners in their (Continued ou next page) Opens Way to World Wireless immediate vicinity. These "Radio repeating is the `open sesame' local broadcasters, therefore, to world -wide wireless and will make pos- need only a small amount of sible the receiving of programs from any power. This interconnected part of the globe, with the same ease with international system will have which we now hear programs from sta- a despatching organization to tions located only a few miles from the direct how and when the va- radio receiver. rious programs of the central "Naturally, before world -wide wireless stations will be sent and what is a reality, there will have to be installed stations should stand by to special stations in various parts of the handle the program circuits. globe and these stations must be located "Such a system will also advantageously. need a world -wide and very efficient program - collecting "Radio repeating when it was first suc- organization. This program cessfully accomplished was the outcome of the development of short wave transmitting. Short wave transmitting means the sending of radio signals on a wave length of 100 meters or lower. Because this wave length is so low it is not heard on the ordinary receiver, and we therefore call it the inaudible wave. The ordinary broadcasting wave length band for 250 meters to 600 meters is heard, of course, on the ordinary receiver and is termed the audible wave. Inaudible wave transmitting forecasts the following radio development : "Certain well designed central stations will be located at the world centers. These SPEAKING Kadel & Herbert stations will be equipped to transmit on OF POLITICAL EXPERTS the audible or the inaudible wave length Graham McNamee, the "sport reporter" of Station WEAF, ought to be one by this time. For he reported the daily doings of the hectic Democratic nomination or both as desired. The audible wave convention at New York last month. His voice was need not have heard by inestimable millicns transmitter excessive power. of radio fans throughout the country when several stations co- operated in simulta- so that its operation will not interfere with neous broadcasting of the historic event. McNamee is a St. Paul native and was distant tuning by adjacent receivers if a concert singer before taking up the microphonic profession. 14 RADIO AGE for August, 1924 The Magasine of the Hour "Perhaps an event of world -wide importance takes place in Pittsburgh. KDKA could duplicate the inaudible and audible wave length transmitting and the des- patcher would instruct the `booster' station to send along only KDKA's inaudible wave length signals. "Thus this station's program would be the one that would be repeated by repeating stations located at any prearranged points on the globe and the signals could be received in Shanghai, San Francisco. London and Sidney, Australia, with the same intensity as signals are now received when transmitted by stations located at those points. "This system means world -wide radio and it also means less interference to the radio listener, for, with a selective receiver, he could still hear long distance stations, even though the local station should be repeating a London program picked up from the inaudible wave source." Radio Association Official Raps Plan for Super- Stations The recent announcement of the Radio Corporation of America that the big electrical and radio companies of the country had decided to establish ten super- broad- casting stations in zones throughout the country is of considerable interest to radio manufacturers, broadcasters, dealers and the public at large, according to Alfred M. Caddell, secretary of the. American Radio Association, New York City. "The proposed blanketing of the country by super -broadcasting stations certainly blankets a lot of opinions that might want to be expressed before such a Kadel & Herbert policy would be put into effect," said Mr, AMPLIFYING SPEECH ONE BILLION TIMES Caddell. That's what this bunch of lily -like amplifiers does when someone talks into the "While it is stated that such a broad- microphone connected to it. Twenty -four amplifying horns are shown in the casting system would not interfere with photograph, which was taken recently in Madison Square Garden, New York. This huge radio attachment will be used in future meetings, including the Radio local stations which take care of local World's Fair next month, to speed the proceedings to a listening world. needs, experience has shown that unless exceptionally selective receivers are used. it is impossible to tune out stations using Common Law Could Handle sion of competition and unfair trade a carrier wave of high power. This was Radio, Claim practices. the present anti -trust laws could handle A from demonstrated recently when the Repub- Legal questions out of interfer- it. monopoly arising patent arising however. be lican National Convention was broadcast ence between users of radio could prob- ownership. could not broken, for reasons in over the entire country -very few other law. in the that are inherent the patent ably be settled by common law. stations could he picked up by average opinion of Hon. Stephen B. Davis, solic- radio receivers in any section of the coun- itor for the Department of Commerce. The most difficult communication prob- try. In speaking on this subject before a recent lem in the army, according to Maj. J. O. "The radio business has been built meeting of the Federal Club at the Bureau Mauborgne, the next speaker. has hereto- largely on the thrill of getting distance, of Standards in Washington he called at- fore been that of keeping in contact with and if this thrill (and therefore other sta- tcntion to the fact that, while common advanced troops in battle. All forms of tions) becomes destroyed by blanketing law is based almost wholly on precedent. communication in use in the past war the country steadily with high power, it it is often modified by court decision to proved inadequate, he stated. He then might lead to serious consequences in the meet new conditions, such as have been told of a portable radio set developed radio world. . created by radio and aircraft. toward the end of the war which is ex- "Everyone knows that radio broadcast- Under the constitution, Judge Davis pected to solve this problem. ing needs a complete overhauling and that stated. the control of radio apparatus There are a great many radio sets on the present lack of economic stability sur- with regard to structural and safety fea- the battle front, he said, and the problem rounding broadcasting cannot endure, but tures properly belongs to the individual of assigning wave lengths to them all is a the public and the independent broadcast- states, but the Federal Government would eery complicated one. The wave lengths ers naturally want to be heard when it control the interstate commerce features, and call letters must be changed every comes to the overhauling. and could regulate any broadcasting sta- day or so. in order to avoid giving the "To this end the American Radio Asso- tion whose signals could be picked up enemy a clue to the nature of the sending ciation is conducting a contest in which a outside the boundaries of the state in station. Radio sets are carried by tanks, $500 prize is offered for the most practical which it is located. airplanes, and advanced infantry units, solution of the problem, and it may There has been some fear of a radio and form part of the equipment of ali reasonably be expected that a constructive monopoly. the judge said, but if this mo- grades of headquarters and of artillery solution will be found." nopoly carne about through the suppres- brigades R_11)10 AGE for August, 1924 The Magazine of the Flour 15 Vacuum Tube Circuits Without "B" Batteries By JOHN B. RATHBUN ACONSIDERABLE amount of inter- lower end is the usual ground connection est has been awakened in this English 4- Tube at (g). Impulses entering the aerial cause country as well as in Europe by the Element variations in the electron stream between appearance of an English four -element Based on `Unidyne' Idea; (P) and (F) and these variations in cur- tube which does away with the necessity rent flow cause sounds in the phones (H). of the usual plate or "B" batteries. This Has Faults, But Tests The plate (P) is not strongly charged to tube, the joint invention of K. D. Rogers a positive sign, and the electron emission and G. V. Downing, is based on what they Indicate Possibilities is comparatively weak, so that the signals term the "Unidyne Principle" and is ap at the phones are not much stronger than plicable to regenerative circuits where the with the ordinary crystal detector. By three -element tube is commonly used. and three -element types so common on connecting the positive pole of a high While the idea is not basically new, and the market at the present time, for it is voltage battery to (P) the stream or emis- experiments in this country have shown only by this comparison that we can see sion is greatly increased and the signals that the principle has several inherent how the four- element tube functions. are correspondingly increased in volume. disadvantages, yet the four -element tube In Fig. 5 we have the two -element tube shows promise and we will undoubtedly The Two -Element Tube to which the high voltage plate battery hear more of it in the future. In Fig. 3 we show an ordinary incan- "B" is added with the positive pole con- In Fig. 1 we show a sketch of a four - descent lamp bulb containing the usual nected to the plate. The battery "A" is element tube in which the terminal (A) hairpin filament (F). The filament is simply used for heating the filament as is the connection of the second grid to heated to incandescence by the battery before. As the plate (P) is now given a the positive side of the "A" battery. The (A) and the temperature is controlled by strong positive charge there is a powerful remaining connections to the plate, the the filament rheostat (R). At high tem- attraction for the negative electrons and first grid and the filament, are made peratures, electrons are emitted from the the velocity and rate of emission is very through the four prongs in the base as surface of the filament as indicated by much greater than in the case where the with the conventional three -element tube. the short arrows (e), and as there is no positive plate charge was maintained sim- For convenience, the terminal (A) can be control over these small negative charges, ply by induction. A comparatively heavy connected to the metal sleeve of the tube they fly off the filament in every direction. current now flows in the plate and "B" mounting, and can thus be used without Now consider the case where the plate battery circuit, and also through the vac- much complication in metal sockets. It (P) is placed in the vacuous space with uous space between the filament (F) and should be understood at this point that the filament (F) as in Fig. 4. The plate the plate (P). This system, however, will the second grid, or the fourth element of (P) is given a slight positive charge by not give a signal in the phones since the the tube, is maintained at a positive poten- induction, and as the negative particles or current is continuous and unvarying. To tial and in close proximity to the filament electrons are attracted by the opposite produce a sound in the phones there must so that the electrons are set free by the positive plate, they stream across between be a variation in current strength in the attraction between the minute negative (F) and (P) and form a continuous phone circuit. electrons and the positive grid. In other bridging current. This effect was discov- words, the second grid (A) performs a ered by Edison many years ago. As long The Three -Element Tube part of the functions of the plate used in as the electrons are emitted by the fila- The three -element tube of Fig. o is the triode tube-that of increasing the ment, a current will be established through basically the same as that of Fig. 5 so far electron emission of the filament. The the inductance coil (L), the phones (H) as the output circuit is concerned and plate now is simply the output terminal and the gap between the filament (F) and includes the "B" battery for maintaining with the first grid functioning in the the plate (P). This is the simple two- the positive plate charge. Interposed be- usual way. element tube commonly known as the tween the filament (F) and the plate (P) Fig. 2 is a schematic diagram or symbol "Fleming Valve" and is now represented is the "Grid" marked (G) which is used of this tube where the elements bear the commercially by the Electrad Diode and for the control of the electron stream same letters as Fig. 1. the Dietzen tubes. passing between the filament and plate. To understand the operation and con- The grid in practice is a cage surrounding struction of the four -element tube we rHE aerial (An) and the variable con- the filament (F) composed of a spirally must first take up the construction of the denser (C) are connected to the upper wound wire coil, and in order to reach simpler tubes, such as the two -element end of the inductance (L), while at the the plate the electrons must pass through

PR/ /NARY TUN /NG CO /L

A B F/G. 3 F/G.4 F/G, EM/SS/ON TlNO ELEMENT CY/PCU/T / LATE BAT TE.PY 16 RADIO AGE for August, 1924 The Magazine of the Dour words, have short circuited the posts where the "B" battery was formerly connected. The positive pole of the "A" battery will now maintain a low voltage positive charge on the plae (P) and the signals will continue to be heard, but with greatly reduced strength owing to the lower voltage of the "B" battery. This circuit is shown by Fig. 7 with the "B" battery removed and where the "A" battery alone maintains the plate at a positive potential. This arrangement works fairly well on strong local signals with six -volt tubes, and would no doubt work very much better with tubes having the filaments designed for a 22.5 to 45 -volt "A" FETU.P/V battery, F/6.Z as then we would havé a much F/6./ SYMBOL S /NO CONNECT/OVS more effective voltage on the plate. TUBE A..SEMBLV Signal strength and distance are both very much increased by the adoption of the meshes of the grid. acceleration or impedance depends upon the "Regeneration" or "Feed- back" prin- By means of the tuning inductance (L) the magnitude of the voltage applied to ciple by which a part of the plate circuit and the variable condenser (C), the circuit the grid. For each volt impressed on the is fed back into the aerial circuit for re- is tuned to the frequency of the incoming grid there is a definite flow of current in amplification in the tube. Thus. in Fig. 8 radio waves, and when tuned in, the im- milliamperes through the phones with a we have a typical regenerative circuit for pulses from the aerial are communicated constant "B" battery voltage. A milli - a three -element tube where the aerial directly to the grid (G) through the grid ammeter placed in series with the phones impulses pass through the primary coil condenser (K). As these radio currents and "B" battery as at (MA) will plainly (L1) and induce charges in the sec - are alternating currents, the grid is given indicate the fluctuations of current taking endary coil (L2) which is connected to alternate positive and negative charges place when the circuit is receiving signals. the grid (G) of the tube. The plate out- which vary in amplitude with the sound The needle of the meter will swing back put at (P) is very much stronger than the or modulation impressed upon the carrier and forth in almost direct relation to the aerial currents, as before explained, dut waves at the transmitting station. The intensity of the sounds heard at (H). to the relaying with local battery current. charge on the grid now corresponds to the The strength of the received signals is Hence, if we feed back this amplified cur- charge on the aerial circuit, and the grid roughly proportional to the plate voltage rent into the secondary coil (L2) by means in turn varies the flow of electrons impressed by the "B" battery when a of the "Tickler coil" (TC), we will gain between (F) and (P) to correspond ex- hard amplifying tube is used. Thus, with an additional amplification since the im- actly to the variations taking place in the 16 volts on the piate, the voice and music pulses will be fed through the tube a aerial. may be quite faint on local stations, but second time and will receive a second As a result, the current flowing through when the "B" battery voltage is built up amplification. Instead of the feeble aerial the phones (H) pulses in step with the to 67.5 or 90 volts the signals are very impulses acting on the grid (G) alone, we modulation (sound) waves and the trans- much stronger because of the increased will also have the stronger plate impulses mitted speech or music is heard at (H). emission and velocity imparted to the acting inductively on the grid, which The grid can be really considered as a electrons. This, however, is not so marked very greatly increases the effective grid valve which controls the relay battery on distanct stations for the reason that potential. current in the plate circuit, the valve the grid potentials are now too feeble to The Four- Element entirely control the tremendous emission Tube being opened or closed to check or accel- WE now arrive at the four -element and hence the electron stream is not so erate the electron flow by the very feeble tube, which in many respects resem- impulses acting on the grid. completely modulated by the grid as when the were bles the three -element tube. We have the grid potentials stronger. same filament and plate and also the same WHEN a negative charge enters the Three Elements Without control grid as before, but in addition grid (G) the grid is charged nega- "B" Battery to these elements is a second grid which tively. and the circuit is interrupted for Now let us consider that we have dis- maintains a positive potential independ- the reason that the negative electrons are connected the "B" battery in Fig. 6 and ently of the plate. The plate in this case repelled by the grid and returned to the have then connected the phones in the is simply an output electrode. filament. therefore never reaching the plate circuit directly from (2), or in other In Fig. 2 we show the four -element tube plate (P). This interruption gives a click or sound in the phones (P). A succeeding wave of positive polarity charges the grid with a positive charge and accelerates this attracts the electrons and TO the flow between (F) and (P) at a speed above normal. This increased plate current gives a second sound in the phones. A very feeble charge in the aerial and grid is therefore capable of controlling a AUO /O FRED. TRANSFORMER considerable flow of battery current, and /O TO / RAT/0 the initial wave is therefore "Amplified" or multiplied many times. The positively charge plate (P) tends to maintain a LI / PHONES steady flow of battery current through LZ (ouTPUT) the tube, while the grid charge varies the amplitude or magnitude of the phone current in direct proportion to the amplitude of the incoming radio waves. A positive charge on the grid (G) flow F76.9 increases the rate of electron or emis- POUR ELEMENT TUBE C//FCU/T sion while a negative charge tends to impede to flow. The exact degree of RADIO AGE for August, 1924 The Magazine of the Hour 17

in diagrammatic form so that its relation somewhat of the reflex principle. This, Tubes Replace Spark Signals to the three -element tube can be more in general, is the "Unidyne" circuit, which, easily followed. Here we have the fila- however, is subject to as many modifica- on Lighthouses ment (F), the plate (P), and the aerial tions as the circuits of a three -element Marked improvement in the sending of grid (G2) as before. Placed close to the tube. wireless fog signals from lightships and which filament is the second grid (G1) Original "Unidyne" Developed by lighthouses has been achieved through the connects to the positive side of the (A) development by radio engineers of the battery and which is therefore constantly U. S. Manufacturer? General Electric Company of a vacuum maintained at a low positive potential. There has recently been released in tube radio transmitter expressly designed No "B" battery is necessary for the reason various radio publications information for this sort of work. that the positively charged grid (G1) pulls concerning a circuit brought out by two In tests which have just been corn - negative electrons from the filament radio men London, which does away the of pleted on Staten Island, the new tube set in same and increases the emission the with the separate "B" battery. showed superior efficiency as compared way as the older charged plate did the job This circuit employs a four -element with the typical spark set of the type used lower potential. In fact, the whole but at a tube which contains two grids as indicated for a number of years by the United Fig. 7, except scheme is reminiscent of in the diagram above. The extra grid States Bureau of Lighthouses. that the extra grid is located more advan- is inserted between the usual grid and fog the ordinary During the tests both of the signal tageously than the plate of filament. It is made positive by being radio transmitters were adjusted to about tube. connected to the positive of the "A" bat- ten amperes in the antenna. It was found The tube shown in Fig. 1 is a develop- tery and it is placed so close to the fila- that the total power consumed by the Fig. 7 made some time ago by ment that pulled away ment of the electrons are spark set averaged around 2,300 watts, writer in which a commercial tube was from the filament and hurried to the the nearly 50 per cent greater than the power economy. plate. Added is remodeled on the score of velocity given them by consumption of the tube set, the latter to more recent schemes the idea the extra grid. Owing being about 1,650 watts. was finally discarded in favor of more This circuit has been named by its Eng- This will have a direct bearing on the fields. lish inventors, the Unidyne. However, promising of fuel to lightships original "Unidyne" circuit was devel- question supply and the since power for The Four -Element Circuit oped by the engineers of the United Man- lighthouses, the these sets Fig. 9 is a general schematic circuit of is supplied by gas- engine driven gener- ufacturing & Distributing Company of - ators, in which kerosene is usually burned. the regenerative type in which the four Chicago, and they have the name is used. This is only one of If the lightship or the lighthouse is element tube "UNIDYNE" registered in the U. S. located in an inaccessible position, as is a great many such circuits possible, and Patent Office, according to a bulletin re- it is likely that expediments in four - often the case, a considerable saving in leased by . the United Manufacturing element hookups will develop more highly Company last week. fuel and other expenses can be effected if fuel are not required make efficient schemes. The plate (P) output The United "Unidyne" Receiver is the ships to the as frequently as is fed back inductively into the secondary result of over a year of experimenting trip at present. coil (L2) of the coupler in the usual way and development work by renowned engi- The tube set was shown to be safer by (TC), the secondary being tuned by neers. to operate and much more simple than the variable condenser (C). The grid the spark sets heretofore used, and the (G2) is connected into the secondary cir- signals were clearer and better toned, cuit through the grid condenser (K) and making them easier to read. grid leak (KL). The spark sets heretofore used have At (G1) is the second grid, which is caused many complaints to be sent in by connected to the positive side of the "A" listeners to broadcasting stations because battery. The phones (H) can be placed in of their tendency to originate interfer- series with the plate and tickler (TC), or ence. This condition will be remedied by else the special audio transformer (AT) the use of the tube sets, which possess can be connected as shown to increase the a non -interference characteristic. volume of the signals. Here, the phones The outcome of the tests with the new (H) are in series with the secondary (1). set was a recommendation by J. T. Yates, The primary and secondary have a com- superintendent of lighthouses of the third mon connection at (a) and both coils are district, to the Bureau of Lighthouses in in series with the plate circuit. Washington, asking that these tube sets This is a rather novel connection and it be adopted generally for the bureau's would seem at first glance to partake radio beacon stations. 18 RADIO AGE for August, 1924 The Magazine of the Hour

The leaks are now seasoned a few days The Heart of the Radio just as you bake steel. Next, the element is carefully inserted By ERNEST WALKER SAWYER in the glass tube or other insulating case, CHIEF ENGINEER, ELECTRAD, Inc. and the ferrules are soldered on each end to further protect the element from con- PART 2. Just as a copper conductor carries low tact with fingers and atmosphere. Glass I\ A previous article I showed you the frequency currents in a smooth. proper cases are most common. but there are importance of the proper size grid manner, because each molecule of copper other insulating materials now in use, leak. I hope you had the opportunity of has its functions to perform harmoniously where the dielectric losses and insulating testing my advice by trying a different with its neighbor; so likewise or even qualities are considered better. size leak in your set. more so should the substance of your grid The finished grid leak is again tested Now I want to explain to you why it leak element be so composed that the and labeled or stamped and certified is so important for you to have grid molecular displacement of the carbona- correct. It is now ready for use. leaks which are manufactured by respon- ceous conducting material should be There has in the past been considerable sible people who will certify they are equal throughout the entire cross sec- propaganda on grid leaks to the effect correctly made and guaranteed. tional area. In plain English, the grid that if your grid leak is the incorrect Here is the Heart of the Radio. The leak element should be made of a mate- resistance, you can compensate by adjust- source of success or failure of the set rial which is exactly the same in the ment of your variable condenser. This and yet a careless pencil mark has. until interior as on the surface or you will get is an absolutely incorrect method of pro- recently, been permitted even in expen- the zigzag jumps together with the noises cedure. As you can readily see. one can- sive sets of well known manufacturers. as in lightning. not adjust resistance by altering capacity. In the grid leak. you are dealing with The elements of many grid leaks are If your grid leak is the wrong size. you minute electrons of electricity passing made of a paper in which carbon in the must get another. If they are certified over a path of extreme high resistance form of lamp black has been defloculated correct, then you know what you are get- 500,000 to 30,000.000 ohms. Here is the through the pulp during the process of ting and can try out several sizes until essence for a great deal of research work. the paper manufacturing. This is one you find the one best suited for your The problem of handling such minute por- method of obtaining the desired result. particular requirement. tions of electricity at such extraordinarily After the paper is cut to the desired high resistances resembles somewhat the size for the grid leak required, copper or problems of dealing with lightning. Two brass clamps are fastened to each end or Canadian Tries to Reach MacMillan storm clouds are filled with energy. The some special method is used to make con- electricity generated is enormous; the tact between the element and the ferrules Toronto. Canada. -William Choat, local path between the clouds or from the or ends of the grid leak. These contacts radio amateur and radio operator for the cloud to the earth is possibly a mile of likewise are extremely important, as a Canadian government steamer "Arctic." thin air. Its resistance is beyond com- loose contact means a noisy grid leak or which left Quebec the first of July on her prehension. Finally the pressure becomes one of very high resistance. annual trip to Baffin Bay, may be the first so great the electricity jumps. An electric current is now passed through amateur operator to relay back to Can- If there was a copper wire or other the element to season it. An analogy to ada and the United States the complete easy conducting path. there would be no this might be shown as the passing of a details of the Winter experiences and zigzag and no thunder. It is exactly the current through a piece of iron to form a home -coming arrangements of Captain same in the receiving set. The accumu- permanent magnet. The atoms of lamp Donald B. MacMillan, Arctic explorer. lated charges jump along the grid leak. black align themselves in perfect regular The departure of the "Arctic," under If the path is a perfect conductor. there order, end for end. so as to offer the the Northwest Territories Branch of the is no noise. If the grid leak element is smoothest possible path to the passage of Canadian Department of the Interior, uneven or only partially a conductor, the small current for which it is intended. comes at a time when the arrival of day- then the grid leak actually creates noises Next the elements are treated with light in the Far North is beginning to in your set. You will realize from this waterproofing compounds, usually of se- shut off the radio contact between Mac- the importance of a proper element in the cret formulae. as the waterproofing matter Millan and radio amateurs of the United grid leak. must not affect the element adversely. States and Canada. The radio messages that have come from Donald Mix, the explorer's radio operator. last Fall and Winter have become gradually less frequent as darkness began to leave the polar regions. Of late there. have been only a few weak messages that have sufficed to show the "Bow - doin's" crew have come through without hardship. The last one told of the explorer's plan to start for home soon. On its annual trip. the "Arctic," which this time is in charge of J. D. Craig. M. E. I. C., and Captain Bernier, famed Canadian explorer. sails as far north as Etah, Greenland. Last Fall, on their arrival in that harbor, the "Arctic's" crew found the "Bowdoin" there and one of them took a snapshot of MacMillan's little schooner as she lay at anchor near the shore. This year the "Arctic" will carry a short wave I. C. W. outfit which will enable its operator to transmit on the Moro from K,del R Herbert amateur wave lengths between 100 and A ONE TUBE TRANSMITTING SET 150 meters. This equipment is in addi- The photo shows the interior of a transmitting set built by George B. Myers of tion to her two regular sets. consisting of Athenia, N. J. It operates on a U. V. 201 tube, 23 plate condenser and an induc- a standard 600- meter. 2 k. w. spark trans- tance. Also a Ford spark coil is used and a glass plate condenser for supplying mitter and a continuous wave transmitter the high plate voltage. working on a 2,100 -meter wave length. RADIO AGE for August, 1924 The Magazine of the Hour 19 Radio Drawn Into Field of Magic by Queer Tales of Ether Bogies

Scientists Are Baffled by Accounts Verging on Supernatural

BY CARL H. BUTMAN

WASHINGTON. -Radio supervisors and inspectors hear many queer tales of strange messages. sounds and calls emanating from somewhere within the boundless realms of téd'.`"'-ts: ü9tl4',"';49J!Y ül7iLatZ3PciUl?thtft5+lstfiflH:ttÇ°tt' radio land. Some complaints are weird. a few pathetic and still others almost convince one that there are Ethereal Bogies. Radio is of itself more or less of a marvel and a mystery, with the rapid advancement of its range, manipulation and scope. and it is small wonder that certain susceptible fans and even operators long in the game hear or imagine they hear curious and unaccountable messages verging on the supernatural. There is the story of one old -timer who declared that he no longer needed head phones, his ears having become so tuned to the notes of code stations that he could pick up messages from almost anywhere. Some of these complainants perhaps improperly classified as bugs of the ether. insist that they are haunted by "Hertzian spooks," which in certain cases seem to approach from the spiritual angle and assume radio control of their victims. They not only exercise an undue influence but create actual fear in the hearts and minds of those persecuted. Certain students of the problem refuse to believe that it is all imagination, attributing the influence to something supernatural or at least a power not yet understood.

Does Radio "Control" Exist? !Cadet & Herbert. Of many cases reported to the Depart- CABINET AUTOMATICALLY CONTROLS TUBES ment of Commerce, there is none so strik- This unique set, constructed by Harold Herbert, radio engineer of New York, ing as the "Strange Case of Operator and valued at more than $500, operates when the cabinet is opened and auto - Blank," on which there is a thick file of maticaly turns off the tubes when the front is closed. It is an eight -tube Super-. papers: Heterodyne with two tuning controls entirely self- contained. Nearly four years ago a sea -going radio operator of twenty years' experience re- night, no matter where he was. Their mitted on various frequencies and were ported to the supervisor of a coastal dis- sinister influence, he felt sure. was affect- impossible to ignore. trict that he was the object of radio per- ing his young daughter when she was near Operator Blank believed the young men secutions in the form of radio telephonic him, and practically broke up his home. had invented an ultra -modern transmitting messages which were transmitted to him He appealed to scientists, doctors, radio set of which no one knew the circuit. He continually by virtue of wired -wireless experts. the government and police with- said the boys told him it was a wired when he was ashore. out benefit, as the source of the radio wireless psychometer affecting the trans- Three unprincipled young operators, he emanations could not be traced. They mission of speech by a therapeutic oscil- asserted, kept a surveillance over his every seemed to come from a coastal point.. lator, and received by triplex phantom - move, reading his thoughts, and at times Even while on an automobile trip across ining attunement. He couldn't get away "neutralizing" his brain action. These the continent and into Canada, the "phan- from the messages, and he was certain three persecutors relieved each other, but tom" radiophone or photophone message: that the boys kept a log of his thoughts. kept up their vocal messages day and pursued him. The messages were trans- (Conti,Twd on next page) 20 RADIO AGE for August, 1924 The Magazine of the Hour And Still They Pursue Getting a Stranglehold Static Later on, when he was again at sea, the on messages pursued him, evidently through the medium of radio. In the Atlantic or Explaining that static is usually due to frame a few feet square may be used, pro- Pacific the effect was the same, and the distant electrical disturbances in the upper vided the receiving set is so designed as operator came to believe that the primary atmosphere, and the trouble is generally to permit operating with such an antenna. phonetic effect kept his head aching con- less the higher the frequency to which the The coil antenna has the added advantage tinually; sometimes he was driven from receiving set is tuned, the radio laboratory that it can eliminate, by virtue of its di- his radio shack. He was certain his death of the Bureau of Standards, of which rectional characteristics, the atmospherics could be caused by these boys if they J. M. Dellinger is chief, offers the follow- that come from a specific direction. desired. He again took up the matter of ing suggestions for meeting the difficulty: "Another means of reducing the inter- locating the station with authorities in "There are no known methods of com- ference from atmospheric disturbances is New York, San Francisco and Washing- pletely eliminating interference caused by to use a very selective receiving set. Two - ton, but no one was able to aid him nor atmospherics in receiving sets tuned to the circuit receiving sets, using loose coupling, locate the unknown station. Unofficial commonly used radio frequencies," he are preferable to single- circuit sets for and unsigned messages continued to follow says. this reason. Radio -frequency amplifica- him, causing interference with his regular tion, with sharply -tuned transformers, is traffic, his sleep and his mental stability. helpful. Well designed regenerative sets Investigations showed him to be in good are also very selective. physical and mental state, but although Radio Age Offers Unusual "A specialized method is the use of a pronounced sound in his mind and body Features in Its Big `wave antenna,' which is a very low an- and only about 42 years old, he was September Issue tenna, one wave length or more long. literally driven from the sea and his pro- Another way of decreasing interference fession. The growth and improvement of from atmospheric disturbances makes use RADIO AGE, which is especially of a combination of several antennas in Following up some of his suggestions, marked in this issue, has by no radio officials report that spiritualists have such a way as to partly balance out the means reached its high mark in atmospherics. Also, a long antenna may been affected in a similar way, and from either circulation figures or edi- New York came information that com- torial quality. be buried a short distance underground. plaints of this character were increasing- Several new features, the result This type of antenna reduces both the sig- in fact, becoming quite common. De- of months of careful planning and nal strength and the strength of at- partment of Comrperce radio officials say investigation among radio readers, mospherics. Some evidence has been that during the full of the moon com- dealers and manufacturers, are in- obtained to show that certain types of plaints of weird and radio mes- corporated in this number, but not local atmospherics are reduced in a greater unnatural without the promise of many more sages in the ether come in with a strange ratio than the signal strength.. in following issues. "Still another method which has been regularity. Even to date the department Particularly will the next issue and its field staff have not been able to - reported to be of some use in reducing in- that of September-be the best ever terference makes use of the limiting action solve the mystery of Operator Blank's of published, and, we predict, one of an electron tube used in conjunction persecution nor the source of the phone the best issues of a radio publi- messages he reported. cation ever offered to a critical with tuned audio- frequency amplification. It is stated that this method is based on Other curious cases reported to de- reading public. the the theory that an electron tube, when partment include the Western farmer who, Because of the original nature of worked at a certain point on its charac- whenever he was plowing in a field near a new feature to be inaugurated in teristic curve, possesses a limiting action an insane asylum, declared he was September, RADIO AGE regrets that that it is not able to announce its restricting the strength of the signal heard influenced and persecuted by voices which nature in this issue. Some sort of seemed from in the telephone receivers to a definite to come a queer box on the announcement will be made to deal- maximum. Thus atmospherics, although sill of a window in the institution. He ers and in other publications a few stronger than the signal being received, came to Washington in an effort to rid before the September issue is days are equal in intensity to it, as heard in the himself of When on the news- stands, but the reader this "radio control." receivers. This equality in he returned the box was no longer visible, must be patient and trust to telephone signal having been obtained, the and it is understood he was bothered no RADIO AGE'S judgment as to the strength advantage of audio -frequency tuning may further, though it was never wholly ex- real nature of the September sur- plained. prise. be utilized. The result is a partial elimi- The editors can announce, how- nation of interference from atmospherics. From Philadelphia came a story of a ever, that the new RADIO AGE This method is not adapted to broadcast woman who was constantly hearing radio feature will revolutionize the radio reception." voices, especially when riding on a train, publication industry, being as it is although it was long before trains were an innovation never before under- equipped with receiving sets. Another taken, despite the fact it is perhaps To Eliminate Radiation the most practical and valuable woman out West recently wrote that "How can I prevent other radio sets waves from a certain radio station pass service ever offered to radio fans. Watch for the September number from interfering with my reception ?" ask through her house and her person, causing many readers and radio fans continually. a most unpleasant effect; she said she on the news- stands. The front cover will reveal THE special A special organization has recently been could never sleep until the station closed feature -and many more, all of formed among radio engineers to formu- for the night. which will establish RADIO AGE late some method by which radiation or as the finest and most reliable radio "canary bird" interference can be elimi- Now Come Radio Sleuths magazine in the field. nated. During the World War, complaints of Users of Antenella aerial plugs report this type and others attributed to German that this ingenious light socket aerial has spies, codes, etc., came to the department's "Methods are available which partly solved this problem for them and many supervisors in great numbers, some of overcome the trouble. One is the use of have taken down their aerials because they them obviously from people with unsound a small receiving antenna. This may be can get just as good results with the minds, who sought to become radio sleuths a relatively low and short outdoor wire, or Antenella. and desired special transmitting licenses may be an indoor antenna. Such an an- The construction of the Antenella is and stations. Such desires, however, were tenna receives less powerful signals, but such that it makes the house wiring system almost always in the interest of defending this may be compensated by using a more act as an antenna, and because these lines the government, and differed from the case sensitivc receiving set, employing regen- are self -shielding due to conduit wiring, of Radio Operator Blank, and a few others eration or radio -frequency amplification. they do not pick up outside aerial radia- whose radio troubles have never been A small coil antenna or loop antenna, tion and are accordingly ideal to eliminate solved. consisting of a few turns of wire on a such interference, as well as static. RADIO AGE for August, 1924 The Magazine of the Hour 21 Filtered Heterodyne Audio Stages By MARVIN HUGHES REFERENCE has frequently been course, is preferable, but one should note with the audio stages on an independent made in these columns to the fact that at least two inches more will be re- "B" battery as at (B2). However, this that some sort of filter must be quired on the length of the panel than is very expensive and greatly increases the used in the audio stages of a Super - with the more straight audio stages, owing complexity of the circuit so that a single Heterodyne receiver to eliminate the to the introduction of additional appara- "B" is imperative. With a single "B" noises and distortion which frequently are tus. connections can be made as per dotted unpleasantly apparent in this circuit. this Two large inductances of the iron core lines. filter system must not be confused with type are used. This rather complicates the so- called "filter" or transfer coupler matters, since we must arrange these IT WILL be noted that the first single cir- working at radio frequency which is in- parts so that there will be no inductive cuit jack (JD) for the detector circuit stalled at the beginning of the radio fre- interference or transfer of energy through is connected directly across the primary quency stages, or rather between the first the wild flux issuing from the coils, and posts (P) and (+B) of the first audio detector and the first radio amplifier tube. this is not always a simple matter in the frequency transformer (AFT1) . This The audio frequency filter referred to limited space that we have at our dis- arrangement does away with the contact here damps down the "Bumps" and har- posal. troubles often encountered with a conven- monies developed in the first radio stages Preceding the first audio frequency tional two circuit jack and insures that and is effective in clarifying speech and transformer (AFT1) is the preliminary the primary coil is always connected per- music when the loud speaker is used. It filter circuit consisting of the two 12,000 manently in circuit without danger of is almost a necessity with the two stages ohm non -inductive resistance (R1) and noise due to poor contacts. The first of audio amplification. (R2). Connected to the mid point of audio stage jack (J1) is connected across In general, the audio frequency filter these resistances is the 100 millihenry the primary of the second audio trans- system can be divided into two principal iron cored choke or inductance (L1) in former (AFT2) in the same way, so that divisions: (1) That part which comes be- :cries with the 0.01 Microfarad fixed con- in all we have three single circuit jacks tween the second detector tube and the denser (K2). Across this assembly is the in parallel on a continuous circuit which first audio stage which damps down un- 0.005. mf. fixed condenser (K I) which are not interrupted by the insertion or re- desirable oscillations emanating from the functions in the ordinary capacity of a moval of the plugs nor by vibration. This detector, and (2) That part which pre- phone condenser. The reactance of (Li) is of the utmost importhnce in a circuit vents direct "B" battery current from and (K2), together with the damping ef- of this sort where the great amplification entering the loud speaker and introducing fect of the resistances (R1 -R2) elimi- and the heavy "B" battery current makes distortions due I o the constant deflection nates the high frequency disturbances jack contacts a serious problem. of the diaphragm under the stress of the which may originate in the radio fre- The secondary coil of the first audio "B" battery current. The first element quency 'stages and detectors, and "irons transformer (AFTI) connects to the grid precedes the audio amplifier, while the out" the bumps before passing to the pri- of the first audio tube (T1) in the usual second comes between the amplifying mary coil of the first audio frequency manner. Both tubes are given a negative stages and the speaker. In addition to transformer (AFTI). Also see Fig. 2 for bias by the "C" battery shown which has these devices the conventional grid bias- assembly. its negative pole connected to both the ing "C" battery is installed, which is a -( -A) posts of the two transformers by further aid to clarity and which mate- Watch Detector Tubes a common connector. The positive pole rially increases the volume. Connections at (B1) and (+22) de- of the "C" battery goes to the ( -A) pend largely upon the nature of detector lines. For a 90 -volt potential on the Two Inductances Needed tube used and on the "B" battery ar- plates, the "C" battery biasing voltage FIG. 1 is a diagro.m of the complete rangement. If a soft detector of the should be about 4.5 volts, and from 610 9 two stage filtered amplifier which is UV200 or the C300 type is used, then a volts for plate voltages much above this. connected to the second detector tube at tap is made at the 22 -volt terminal of the So much has.been said upon the subject the "INPUT" end or at the left of the "B" battery. If a hard tube such as the of the "C" battery in its relation to vol- diagram by the connecting posts (x) and UV201A or C30IA is used which, by the ume and grid stability that it seems al- (y). The connection (x) is made to the way, is better practice, then (y) can be most unnecessary to enter into a discus- plate of the detector tube (P') as usual. connected to the 45 -volt tap. For the sion of its functions at this point, but it The circuit can be installed in the same best results it is very desirable that the should be understood that it is one of the cabinet with the main heterodyne circuit first radio stages, the detectors and the most important adjuncts to the system or in a second cabinet. The former, of oscillator be carried on one "B" battery and should not be omitted under any conditions. Condensers (K4) shown dotted are optional and may or may not give improved results. (.0005 mf.). Trip/e Maul-7i»g 7'?ANS To minimize the number of controls on the panel, both tubes (T1) and (T2) are controlled by the single rheostat (M) inserted in the negative lead of the tubes. Separate rheostats can be used of course, but it is not advisable to enter into more complication than absolutely necessary, even at the expense of an extra tube burning when only the first audio stage is being used. Under most conditions, the set will be operated on both audio stages with the speaker plugged in on the output jack (J2). +A -B The Output Circuit Now we come to the final or output .96. 2. //7a" Fi/fer Circai/ /c263 Output Stop circuit of the second tube (T2). Ordi- SI/O[N/NG Gef2UPOFUN/TS ANO THEM' narily the connections from the plate and MOUNT/NG.S ANO CONNECT/ONS (+13) are connected directly to the output. but this introduces certain difficul- RADIO AGE for August, 1924 The Magazine of the Hour

/npu/ Fi//er Circuif o r

(K) /2, pooa. /2, 000., AFT -I TI .P2

K ci /oom.h .005 /f2 .0/

C B2 tBZ 90 !/o/fs(B Fie. / /7//ered Two Sfages of,4u o for 1/eferoay/e ties in the loud speaker and distortion in In locating (L1) and (L2) we must and for this reason are essential where the final stages. To remedy this defect, take every precaution against magnetic the maximum volume is to be obtained the fixed stopping condenser (K3) of 1.0 coupling and interference. The coils when the set is to be used in large halls mf. capacity is inserted in the plate cir- should be kept as far apart as practicable or for outdoor service. Up to 350 volts cuit to interrupt the flow of continuous and well away from tuning inductances may be used on the plates of these tubes "B" battery current that ordinarily takes and the transformers. In all cases they and the amplification is in proportion, loud but be borne in mind place through the coils of the should be laid out with the cores at right it must that such speaker. This relieves the speaker dia- voltages call for heavy plate currents and angles to one another and at right angles phragm of the magnetic stress imposed put a heavy demand on the "B" battery. upon it by the battery current and makes to the coils of the transformers so that The use of storage type "B" batteries is it more responsive as only the alternating the flux will not induce wild currents in almost necessary if plate voltages of over audio currents can pass to the coils of the circuits. Enclosing the coils in 100 volts are to be used. the speaker. grounded metal boxes is a great help. for Figs. 2 -3 show the general arrangement As equal deflection is now imparted the boxes shield the adjacent apparatus of the units used for the filters and stops, to both negative and positive waves from the intense magnetic fields of the and their mountings. Fig. 2 is the input there is no distortion due to diaphragm coils. filter with the condensers and resistances reaction. Current from the ( +B) leads Our 12,000 ohm non -inductive resist- placed in the usual spring clip mountings to the plate of tube (T2) and passes ances are of the type commonly used by connected up for use. This arrangement through the iron core choke (L2). which telephone companies and are now to be probably gives the shortest leads. Fig. 3 permits free flow to the plate, but which obtained from the larger and better radio shows the condenser and choke for the chokes down and prevents the audio fre- supply houses. As in Fig. 2, their general output "stop." It is likely that the least quency currents from short circuiting appearance is similar to that of a grid room is taken up when these parts are back through the battery. Some amplifi- leak and they can be held in the same mounted on a small vertical panel placed cation is also due to the "kick" from sort of clips and stands.- Their value is near the rear edge of the baseboard, and (L2), and in general this combination not critical, but in general they should be as no adjustment is required there is no not only improves the quality of the re- as nearly 12,000 ohms as possible and of reason why this will not prove satisfac- ception, but also adds considerably to its exactly equal resistance. Further, they tory. non -inductive so that there volume. Inductance value about 1.00. must be truly 100 -Meter Transmitter Tested on See Fig. 3 also. is no phase displacement. No opposition to the radio frequency component which the Shenandoah TT IS imperative that both (L1) and passes from the plate of the detector That radio messages can come from a (L2) be iron core inductances of the tube. point high up in the air as well as value given, owing to the low frequencies "through it" was demonstrated recently of the currents dealt with in this part of The Tubes when the radio operator on the Navy's the circuit. The impedance of air core Regarding the tubes to be used for the big airship "Shenandoah" gossiped for a inductances while effective with the high amplifying stages (Ti) and (T2), it may while with radio amateurs below. frequency radio currents, offers very little be said that the UV201A or the C301A "To the Rochester amateurs," read the opposition to the flow of audio frequency are the best all around tubes to use. Of message in code. "You are the first currents which are in the nature of 5,000 the dry cell tubes the UV199 or C299 bunch that have woke up today. Best cycles per second. The inductance (L1) are by far the best but, of course, do not regards." can be obtained from the better class of deliver the volume attained with the 'This was not a casual greeting, attempted radio supply houses or from the various power tubes before mentioned. Still fur- as a pastime for the "Shenandoah's" crew, telephone manufacturing firms. Induct- ther amplification can be had by the use but part of a systematic program for test- ance (L2) can be a 1.0 henry iron cored of the Western Electric 216A tubes or ing out the possibilities of short wave inductance, or if desired, the secondary the five watt transmitting tubes such as amateur communication. Some time ago coil of an audio frequency transformer the ÚV202 or C302, but these latter tubes the American Radio Relay League learned can be connected into circuit for this pur- take a great deal of filament current and from the Navy Department that a short pose. The latter, however, is rather bulky with the heterodyne any additional fila - wave transmitter was being installed on and takes up valuable room, but on the ment current is to be looked upon with the airship for the express purpose of other hand, it is comparatively well disproval. enabling its operator to communicate with shielded and causes practically no inter- Both the 216A tube and the five watt amateurs should it be needed in emer- ference tube permit of very high plate voltages gency during flights. RADIO AGE for August, 1924 The Magazine of the Hour 23 Radio is no Longer "Seasonable" By ROBERT J. CASEY The Vest Pocket Anthologist

WHY should radio be a seasonable to the gag rule. A matter of psychology, country see no good reason for a warm - affair-like the flu and the winter Oswald, that only the nimble of wit can weather depression and look upon the coal bill? explain. annual vacation from broadcast as a It seems to be the accepted psychology Taking Off the "Curse" tribute to the memory of the inefficient in the radio business to shut up shop and sets of two years ago. The material works Application of the reflex principle to go fishing at the first breath of Spring. of the hay -wire mechanics' guild have radio sets with battery has made But why? That, Oswald, is one of the real dry tubes vanished. But only a patient and honest possible the re- mysteries of radio. ranks in interest construction of efficient campaign of education extending over a It ceivers, all foot with static, body capacity, and the pro- contained in cabinets a period the length of which no one can long or less, that will a loud posed tax on broadcasting and it outclasses operate forecast will destroy the psychological speaker on a loop. A Summer evening them in importance. But it is undeniably bugaboos that Gyp built. on the front porch or the lawn certainly a mystery. is no less enjoyable for a radio concert, According to the popular conception of and a radio set more than once has been Radio Technical Talks the thing, the entire world goes deaf in known to take the curse off a Summer Over WTAY the Summer time. All the stations quit resort vacation. broadcasting simultaneously - or simul- As for static, most of it disappeared RADIO AGE broadcasts technical talks taneously quit broadcasting, depending on with the wooden variometer and its rough every Wednesday evening from Oak your particular situation. All the batteries looking cousins. Inbuilt crackles in radio Leaves station WTAY on 283 meters at die. And all the "gyp distributors" have sets went out of style with switch arms 9:00 o'clock. Tune in your receivers to their annual fires. and taps and Mexico City sounds just as this wave some Wednesday evening and had in Summer as it does in Winter. listen to the various members of the staff The Cause of It All The Erla canvass shows that distrib- of RADIO AGE tell you the most recent A survey recently completed by the utors and set builders throughout the developments in the radio field. Electrical Research Laboratories of Chi- cago may furnish a clew to the causes of this phenomenon. Two years ago a hard Summer followed a particularly soft Win- ter. Many a manufacturer sighs at the memory of that glorious period when a brace of static -sifters euphemistically called head -phones brought an unquestion- ing $15 and a wooden variometer was considered cheap at $7. Every second -hand clothes dealer who could make a Chinese copy of a piece of wireless apparatus went into the radio manufacturing business and took out more fire insurance. Along about Spring the great mass of radio pioneers had become convinced that radio was a myth. But why go on? The story of that fearful Summer is written in rccords of the bankruptcy courts of every county in the United States. The public had suddenly become convinced that short- circuited coils and contact -less rheostats are an expensive attic decoration. That radio ever recovered from this period of disillusionment is proof enough of its permanence, and of American adjusta- bility. A manufacturer of loud speakers referred to those days last week as he paid off the last of the loan that had saved him from wreckage. Radio revived because it changed. The GypS are always with us. But their numbers are decreasing and it has become possible for a fan to buy standard parts with fair assurance that they will work. The elementary telephone circuits are fairly well understood by a majority of amateurs. And the sounds that come over the radio are quite similar to those sent & A. Photo out by the broadcasting station. Prospects P. EVEN "THE IS A FAN for continuous popularity should be good. SHEIK" RADIO But in the background is the memory of Rudolph Valentino, a favorite with thousands of movie fans he never sees, is himself one of the great invisible audience which listens nightly to radio programs. that terrible Summer. He started by making a crystal set and has worked his way up to the most com- Because of one "silent Summer" it plicated hookups. Here he is shown with Alfred Grebe, the radio engineer, testing seems likely that all Summers are doomed a new 5 -tube set designed by the inventor for Valentino. 24 RADIO AGE for August, 1924 The Magazine of the flour "This is WMC, 'Way Down in Dixie!" How Local Talent Meet the " ÿold Dust Made WMC Popular Twins" of Radio Land

«STATION \VMC, the Commer- L type supported by two 70 -foot steel cial- Appeal, Memphis, Down in towers, 150 feet apart and located on Dixie," has been heard from the four - story Commercial - Appeal London to Hawaii by countless thou- rw Building in Memphis. The ground con- sands of loyal radio fans. From lati- nection for the transmitter is made to tude 20 degrees South and longitude the iron frame of the building. 97 \Vest -a spot in the Parific Ocean -to MacMillan's expedition at 97 Receivers at All Points North, within 11 degrees of the North The monitoring of the transmission Pole, the ethereal concerts of this speech and music is acomplished by popular station have traveled. means of receivers located both at the WMC is owned and operated by the station and at remote points. Commercial -Appeal at Memphis, Tenn. \\'MC has operated on wave lengths It was first opened in Januady, 1923, from 345 to 500 meters, but has ac- and soon became one of the best cepted 500 as producing the best all - known stations in the United States around results. It has been at this

f ,L

H e r.e are the three hard workers who keep things humming from W MC, above is Percy G. Root, chief operator; at the left is Joseph E. Kabakoff, assistant operator; and right, Gerald L. Dearing, c hi e f announcer. w., ?AbL.vi because of the high quality of its programs ing, has picked up where the `Solemn Old wave length that the longest distance and the bubbling exuberance radiated by Judge" left off and is working to make records have been made. the men and women who operated its still better the reputation and popularity \VMC's daily correspondence from fans studio. of \\'MC. Dearing is known in the air all over the country is amazing, Mr. Depending on local orchestras, with as "Jerry," while the operating staff, Percy Dearing reports. some aid from outside entertainers, WMC Root and Joseph Kabakoff, are known to built up a reputation that meant "Varied ether fans as "The Gold Dust Twins." 'Tis a Pleasure "Entertainers like to broadcast from programs with good music and excellent Incidentally, \VMC has the smallest vocalists." Especially were its "genuinely \VMC because they always receive such studio personnel of any 500 -watt station good response from the eager fans who Southern" jazz orchestras popular with the in existence. Four persons outline and Northern and Eastern fans who received listen to them," he explained. "And the arrange the programs, announce, and cheery spirit we try to maintain at all WMC's broadcasts. operate the station. Two work in the Then came George D. Hay, better times makes it a real pleasure to listen studio itself and two in the operating in with us for an evening." known as the "Solemn Old Judge," who is room, the two rooms adjoining. now with \VLS at Chicago. With his Try it some time. You'll know \VMC and its famous The transmitter at WMC is the lA by that "Down in Dixie" flavor of its Good Ship Huspuckiny Electric. The whistle, he inaugurated a bit of foolish type -a 500 -watt Western programs. byplay that took well power supply consists of a three -unit \\'MC is virtually the leader of all and good -natured set, em- with the listeners -in and established \\'MC Robbins -Myer motor generator Southern stations, having to compete only station" with human ploying one low- voltage generator for fila- with those in Birmingham, Dallas and as a real "human -voltage genera- folks behind it. ment supply and one high Fort Worth for first honors. The station, its mythical ship and the tor for plate circuit supply. Hardly a visitor can stay in Memphis announcer soon became nationally known The regulation speech input equipment for more than a day without being asked and recognized. is used for both studio and remote control the familiar question: "Have you seen programs, while the usual two- button our \VMC yet? Dearing Now Announces microphone is used at all times. (Another interesting broadcast feature The newest announcer, Gerald L. Dear- The antenna is of the four -wire inverted in the September RADIO AGE.) RADIO AGE for August, 1924 The Magazine of the Hour 25 How to Tune WLW's 423 -Meter How Radio Waves Travel WJAX Studies Remote Control Wave Length The fact that radio waves can be made WJAX, the Union Trust broadcasting When the Crosley Radio Corporation's to go "there and back in nothing flat" station, Cleveland, has been a pioneer in WLW broadcasting station began using was demonstrated at WTAM, radio sta- Cleveland, as far as remote control broad- their new 423 -meter wave length it was tion of the Willard Storage Battery Com- casting is concerned; that is, broadcasting discovered that several owners of receiv- pany, broadcasting from the Cleveland from points distant from the actual radio ing sets did not know how to adjust their Plain Dealer studio. studio. receivers to tune in on the high wave A late dance concert of request numbers Besides Symphony Orchestra Concerts, length. E. J. Bussard, of the engineering was being put on the air when a fan called which were given at Masonic Hall, there department, prepared the following infor- the studio by long distance telephone from have also been broadcast the organ of the mation for those who desire to make the St. Thomas, Ontario, placed his loud Cleveland Public Auditorium, where the_ necessary changes in their radio sets: speaker to the telephone and sent back big Republican Convention took place; There are quite a number of receiving over the wire the same music that was the orchestras of the Cleveland Hotel and sets on the market, sets manufactured being sent out by wireless fifteen feet the Winton Hotel; the Boys' Choir of one to three years ago, which will receive away. Trinity Cathedral; and a number of Cleve- wave lengths no higher than 400 meters. The speed of the round trip of the land's best known dance orchestras. It can be readily seen that a receiver of signals was so great that the music came A great many people have been under this nature is of no value for receiving back from Canada at the same instant the impression that when a concert is wave lengths between 400 and 600 meters. that it was going into the microphone in broadcast from some point away from the In the majority of cases these receivers the next room. studio, it is necessary to install complete are of the single circuit type. It is rela- To complete the circuit of sound, tele- broadcasting equipment at the place where tively easy to correct this type of receiver phone wires carried the signals from the the concert is being given. Of course that to receive higher wave lengths. The most studio to the transmitting set, seven miles is not the case. common method is to insert a small load- away. From there the ether carried them No matter from what point WJAX ing coil in the antenna circuit. In quite to St. Thomas, about 100 miles away, broadcasts concerts, the transmitters, gen- a few cases it is only necessary to in- straight across Lake Erie. From St. erators, and all other standard station crease the length of the receiving antenna. Thomas they were put on the wire again, equipment, are undisturbed and are oper- Another common method is to remove the going about 400 miles around the lake to ated within the studio. condenser from the series connection with get back to the studio. And the return The concert is carried to the station by antenna circuit and place it in parallel was instantaneous with the start! telephone wires: This involves the use of with the antenna inductance coil of the a private line direct from the place of the receiver. concert to the radio station, together with By a loading coil is meant an inductance three pairs of conductors-one pair for coil; usually only a few turns of wire are regular telephone equipment, in order that necessary, placed in the antenna lead, one the operator at the station 'and the side of the coil being connected to the operator at the remote control panel may antenna lead -in and the other to the have physical means of communication, antenna binding post. the remaining two pairs of conductors be- Should the circuit be tuned by a con- ing installed so that in case one pair should denser used in series with tuning coil or develop trouble, broadcasting could be tuned inductance, the wave length range continued over the other pair. These con- may be sufficiently increased by shunting ductors are given a special test and all this condenser or connecting it in parallel line noises and cross talk eliminated. with the tuned inductance or untuned After the lines have -been made ready, inductance, as the case may be. This can special input equipment including an am- usually be done by connecting the antenna plifier and microphone are installed at the binding post to the . ground binding post place where the concert is to be given and with a piece of copper wire and then con -. are connected to one pair of conductors. netting the antenna lead -in to the wire The lines are then -connected to the connecting the antenna condenser to the speech amplifier equipment at the station inductance coil, should the condenser be and tests are conducted for both audibil- in the antenna side of the circuit. ity and quality. The volume is adjusted ' A few complaints have been received to a certain level in order to insure from people using three- circuit tuners. perfect broadcasting. The difficulty here lies in the type of variometers used and it will be necessary to substitute variometers having the Portugal Adopts Radio proper characteristics for tuning between 200 and 600 meters. In a few cases it Authority to install and operate radio may be possible to wind a few turns of telephone apparatus in Portugal is granted wire on the variometer and correct this in a recent decree of the Portuguese Gov- defect to some extent, but the novice will ernment, says Vice -Consul Moers of Lis- find no little difficulty in doing this. bon. Prior to this action no legal right existed whereby amateurs could install "Quiet Hours" Changed receiving sets, although no objection had Hartford, Conn. -The changes in radio been interposed by the government. transmitting schedules caused by the ob- Stores and novelty shops are now begin- servance of daylight saving time in some ning to put in stocks of radio apparatus. sections and standard time in others have But in Roumania prompted the American Radio Relay League, at the suggestion of the Depart- Roumania has not given as yet official for use private receiving ment of Commerce, to agree to the tem- ESSAY WINS RADIO SET sanction the of porary expansion of amateur "quiet sets, nor ,is there any broadcasting service, hours" from 7:00 to 10:30 p. m., stand- Grace Ann Yaeger, an opera star, of a statement from Bucharest announces. p. m. sav- 23 W. 64th St., New York City, was A goverñment commission, however, is ard time, 8 to 11:30 daylight awarded a $250 radio set recently by ing time. Amateurs are being advised of the Associated Exhibitors for her prize now studying the question and legislation the expansion by the Department and are winning criticism of "The Chechahcos," permitting the use of radio by the public asked to attach the notice to their sta- a motion picture. More than 700 crit- under governmental regulation will soon tion licenses. icisms were submitted in the contest. be requested. 26 RADIO AGE for August, 1924 The Magazine of the Hour

Here Is Your Chance to Pick 1 YOUR FAVORITE RADIO STAR !

RADIO AGE is conducting a RADIO FAVORITE POPULARITY CONTEST to determine which radio announcer, entertainer, musician or other personage is the most popular in the minds of the thousands of fans who listen in on their concerts nightly. Beginning with the next issue, the first tabulation of results will begin. Fans are responding with a will, and several broadcasting stations already have enlisted their co- operation in this contest. RADIO AGE wants to give its readers more news stories and pictures of the men and women who supply their radio entertainment. And in order to do so, we want to find out just WHO are the most popular and who shall be given first consideration in our columns. It is up to you to select your choice. Read the rules below, get your friends together and send in your vote by clipping the coupon on this page. All together for the big competition among the studio stars! Rules of the Contest 1. Readers of RADIO AGE are en- tailler, etc.), the station from which last titled to as many votes as they wish. heard and approximate date when you Each coupon counts for one vote, and were entertained. only those written on blanks clipped from 4. Send in the coupons at once. First RADIO AGE will he honored. tabulations of results will appear in the September RADIO AGE and 2. The candidate must be a person monthly identified with the Radio World and may thereafter until a grand winner is decided he an announcer, entertainer, orchestra, upon. manufacturer or, in fact, any person in any 5. Radio entertainers are usually announced through the microphone, but it is manner connected with the great radio suggested that in the event voters do not industry. know the name of the announcer, they 3. State clearly the name of your favor- should give only the station from which ite, his classification (announcer, enter- he announces.

POPULARITY CONTEST COUPON Harry A'dyne, Contest Editor, RADIO AGE, S00 N. Dearborn St., Chicago.

I wish to cast my vote for

Name of favorite Classification Station Approx. date heard

My name [optional] My address [optional]

- n Zmx[_¢ara.innaa.macRmnTaILrin:nn 4 tT to Always Aleutian RADIO AGE When Writing Advertisers RADIO AGE for August, 1924 The Magazine of the Hour 27 Radio the "Great Discoverer" How One Ambitious but Unknown Youth Won Fame and Fortune Overnight

RADIO has made scores of interesting personalities, all of whom have profited greatly because they had the good fortune to become associated with a new and mysterious pastime. But the real personalities are the young men -and some women -who had the foresight to jump into the doubtful radio fray before it became the rage it is today. Two years ago A. W. ( "Sen ") Kaney was a wandering youngster of about 25 years of age, flitting from place to place without a definite destination -just as thousands of other pleasing but unknown young men were doing. Raney had done some local theatricals and was popular among both sexes at any social event. But that popularity could not be translated into dollars and cents, and his personality was too young and not widely enough advertised to deserve a prominent place on a vaudeville bill. Trusting to Luck So Kaney went along unappreciated, trusting to luck something would happen. It did. When the Westinghouse Elec- tric and Manufacturing Company opened its station, KYW, in Chicago -and, by the way, it was one of the first to be started in that city -a call was sent out for announcers and entertainers. Very few responded. The art of radio broadcasting was new and untried. The try, to go on the stage -take charge of at latest writing, Kaney is Co- Announcer money end of it was uncertain, and alto- other stations-and what not. Prospective with Jack Nelson at WGN, formerly gether the new profession seemed more of offers ran into several figures, and Kaney WDAP, on the Drake Hotel, Chicago. a temporary occupation than a perma- found himself blinking in a new calcium Owners of the station declare Kaney nent calling. of public favor -a new experience for him. has accomplished a radio miracle of which But young Raney had been keeping his Finally he real- he can be proud; eyes open. He grasped at this straw of ized he was a star in namely, he has cre- hope and got a job as part -time an- every sense of the Being the Almost Incredible ated a following of nouncer and fill-in entertainer. He could word -and after a Story of the Jump to radio listeners who sing a little, talk a lot and keep up a run- f e w "rounds" of have shown by their ning fire of conversation that was pleasing vaudeville and "per- Prominence of "Sen" correspondence with to the ear. sonal appearances" Kaney, Chicago's KYW, WGN a n d KYW grew. Other promising but un- in Chicago, he the old WDAP that known young men came over to the ranks, signed up with a Veteran Radio they care more for and by the time the station was well under local newspaper as Announcer Kaney's announcing way, Kaney was the acknowledged "guid- Chief Announcer of and chatty talk than ing genius." WGN, Chicago, a new station. He was to they did the programs he announced. All receive a fat sum to transfer the "fans" `-arch an accomplishment is indeed a com- Kaney Guides It from KYW to WGN and retain their pliment. Elaborate programs were arranged. favor with the same humanness that made One of Kaney's greatest successes in the Famous stage and movie stars contributed his voice a byword in thousands of house- broadcasting line was his broadcast of the their talents to the ethereal concerts - holds. automobile races from Indianapolis on and all with the dominant personality of No sooner had Kaney bet.ume estab- Memorial Day, through WGN. This feat "Sen" Raney hovering about. Before a lished at WGN than that station was again -accomplished in the pit alongside the few months had passed Kaney was flooded sold and moved to another location and track at Indianapolis Speedway, precipi- with offers from every section of the coun- given a new wave length. This time -and tated an avalanche of praise for Kaney 28 RADIO AGE for August, 1924 The Magazine of the Hour that has been unrivaled in the history of without prospects of a promising nature wire will no doubt soon be possible with broadcasting. when radio made its debut. For it brought radio and then the dreams of scientists Kaney has made broadcasting his forte. him fame and fortune and made him the will come true. He has found his bent and he plans to reputed leader of his profession -or at Another interesting reception of the "stick" until his voice gives out. least one of the leaders-and one of the broadcast concerts from WLW was aboard profoundest students of the radio indus- the U. S. S. Orion, when Stanley E. Wolf A Human Calling try as a science and as a cog in human heard the music while his ship was 750 "I believe announcing is the greatest life. miles off the Florida coast. human job there is," this young philoso- After all, Kaney has been successful be- In contrast to the reception of WLW pher says. "You get to more people, and cause he's the kind of a soul who makes on the water, A. K. Almon, operator on gain more friends, than in any other way. friends easily. And that's what makes a the train between Vancouver and Mont- I never realized how many people `knew' successful broadcasting station. real, heard the broadcast concert very me until I began to meet a lot of them in clearly. This radio set was installed aboard person, in theaters and elsewhere. WLW Heard in England the Canadian Railways train and is a reg- "It isn't the glow of satisfaction alone There have been many attempts made ular feature of the service for the con- that makes my work worth while; it's the by stations in this part of the United venience and entertainment of the pas- thought that I'm bringing cheer and States to reach England with their broad- sengers. friendliness to someone alone by a fireside, casting, but it remained for WLW at or helping to inject pep into a party or Cincinnati to reach the goal. Henry Field, A Foreign Radio Record meeting of some kind. Announcing is a who operates Radio Station 6ZX in Bag - An amateur in the Pyrenees district of public service and an art that's going to grave Hall, Leicestershire, England, heard France claims a record for the reception be as necessary as life in a very short the station clearly as it broadcast the of American broadcasting. With only two time. I started with radio and I hope to Chubb -Steinberg orchestra's regular mid- tubes he receives nightly the American finish with it." night concert. stations WGY, on 105 meters, and KDKA Therein lies "Sen's" reason for his suc- This is a remarkable achievement which -both on the loud speaker. He has also cess. marks a new era in broadcasting. The to his credit over 500 American amateur Perhaps it was luck that Kaney was recent success of sending photographs by stations.

AND ANOTHER REDSKIN BIT THE DUST! It takes considerable imagination to convey realism by radio waves. Here is a "terrible" fight scene from "Pierre of the Plains" as produced from WGY. "Jap" Durkin has fired from ambush at Pierre, who feigns death and falls in the "dead leaves" which carpet the forest floor. When Durkin approaches, Pierre grapples with him and "slays him with his bare hands." Pierre then escapes on his trusty steed. Edward St. Louis, the player at the left, fires the shot; Edward Smith as Pierre is stifling the cries of Frank Oliver, alias Durkin, who is knee deep in onion -skin paper. A microphone on the floor picks up the sound of the struggle and the young woman at the piano depicts the clattering of the horse's hoofs. Quite exciting, eh? RADIO AGE for August, 1924 The Magazine of the Hour 29 Broadcast With Storage How an Announcer Feels Batteries By KOLIN HAGER "The Storage-Battery Station of the Chief Announcer of WGY, Schenectady, N. Y. East" is the new designation of Broadcast- ing Station WDAR, Lit Brothers, Phila- FEW people realize how earnestly we The WGY announcers have all caught delphia, which recently changed its source who are connected with the WGY this spirit and have confidence in this of transmission power from motor genera- studio hope they will listen to our nightly broadening. tors to storage batteries. request for their comments and sug- Two Stations Help The results obtained, in increased gestions. We know that, if we are to suc- strength and clearness of signals, are re- ceed at all, it will be by carefully watching Not so long ago WGY and WJZ joined ported as astonishing. Letters and tele- the attitude and following the wishes of forces, with the result that many good grams commenting on the vast improve- the public. events from New York have already been ment were received by the station from Those who have followed the programs broadcast, notable among these, the listeners all over the country. of WGY perhaps have noticed that the luncheon of the Associated Press, when WDAR is the first big broadcasting sta- average week's broadcasting is carefully President Calvin Coolidge was the prin- tion in the East to equip for operation with proportioned. On Monday evening a cipal speaker. Incidentally, the Presi- storage batteries. Heretofore the uni- brass quartet might be scheduled with half dent's father in Vermont heard the versal practice has been to use motor popular and half classical music. Tuesday broadcasting of the address. generators for supplying the large filament evening we would endeavor to offer either Several weeks ago WGY took part in current and high plate voltage required a drama, a comedy, or a program of music a coast -to -coast program, when we relayed by the main oscillator and modulator tubes in contrast to the previous evening. the alumni dinner of the Massachusetts of the transmitting set. Institute of Technology. Six other sta- Radio Turns to New Field Lit Brothers, who have led the way in making other recent innovations in broad- The travelogue programs, embracing casting, decided that the time had come stories of trips through different countries for improving the quality of broadcasting of the world; the series of addresses by. by eliminating the commutator hum and college instructors; and the many talks on other objectionable features of motor various phases of manufacturing by generated power. Philco Diamond -Grid numerous experts and scientists; all these Batteries were used. help to give greater variety to our broadcasting. The predominance of music, Seek a Better Word which a year or more ago was very evi- Than "Jazz" By dent, is changing now to a greater em- phasis on educational material in the form Radio of school or college instruction, and talks According to Meyer Davis, head of one of the largest by men who are specialists in their par - orchestral organizations in ticular field. Indeed, if radio is to keep up the cóuntry and whose music is familiar its popularity, it must offer a greater pro- to millions of radio fans, the word "Jazz" portion of programs which will make does not represent a true description of people think rather than cause them to sit modern music for dance or song. back and merely be amused or enter- Mr. Davis further states that the dance tained. music demanded today is far removed There isn't any reason why broadcast- from the style of a few years ago, when ing can not be made the school and the the wheeze and shrill of the clarinet, the college for all kinds of listeners. Its fac- blare of the trumpet and the banging of ulty members can be drawn from in- the drums pleased the majority of people structors throughout the country, and its who became dance enthusiasts for the classroom may extend even to the humble first time. This taste has changed for the farmhouse and far into remote places. better to a remarkable degree, and dance music has improved accordingly. But we This should make for a magnificent or- A CO -ED RADIO STAR ganization, but create still call it "Jazz." to and carry on such Rey Marchant, musical an undertaking the government will be between activi- Mr. Davis, in his desire to obtain a ties at the Mills College, manages to more truly descriptive word for dance obliged to take an active interest and be maintain hei- popularity as a violinist at a part in the creation and continuance music of today, has offered a prize of $100 of Station KGO, Oakland, Calif. She is a cash for this work. member of the Mills College Trio and a name to displace the word My faith in the future of this develop- can manipulate popular and classical "Jazz." This prize will be given to the ment is in part due to the sensible let- airs with equal dexterity. Whenever person -man, woman or child-who sends ters we receive. The type of our audience Rey's picture is published, her mail at in the name which will be acceptable to is, I believe, superior to that of the aver- KGO is doubled. Do you wonder? himself and to the executives of his age theater. The better things are pre- organization. ferred, and even strongly urged. tions carried this program on; so that it There are no restrictions in this contest, except It may surprise many to know that we is estimated fifty million people heard it that the number of names submit- have five times as many requests for and England and Cuba received clearly ted by any one person must be limited to classical music-the compositions of the the music and part of the speeches. This five and must be mailed to Meyer Davis' masters and oldtime American songs - is opening up a new phase of broadcast- Music at the New Willard Hotel, Wash- as we have for popular, present -day ing, which by the several relays from one ington, D. C., or the local or nearby music. The general opinion seems to be station to another, can give the listeners radio broadcasting station on or before that popular dance music is the all de- a program from the far West, the far August 15, 1924. The award will be made sirable thing, but according to the requests North, or perhaps from Cuba. We may September 1, 1924, by the broadcasting we receive, it is the reverse. I believe, some day relay the English _programs to station which receives the .winning word., too, that this is a representative judgment. America with the same ease that our own may remember. As much personality as WGY's mail will shortly approach a programs are transmitted today. possible should be in the voice of the an- quarter of a million communications of The studio broadcasting at the present nouncer, and whatever he says ought to one kind or other, cablegrams, telegrams, time at the major stations is being better add to the program, and help in its suc- letters and post cards. Doesn't it seem and more carefully prepared. The an- cess. There must be an optimism and logical that if the people want the better nouncing which plays an important part in brightness in all he says, if he is to hold music, they also want other features of a every program is more dignified and has the interest and have the favor of his high quality? not the former careless tone which some audience. 30 RADIO AGE for August, 1924 The Magazine of the Hour An Audio Amplifier Without an "A" Battery How to Extract Filament Current from the A. C. Lamp Socket By BRAINARD FOOTE

ylANY a man is the owner of a one diately, even with one's ear close to the tube dry cell tube receiving set. Changing the Amplifier for the purpose. The circuit gives also Perhaps he's had it quite a while Certain alternations must be made in the horn. But this slight hum is caused by and feels that the next step for him is to amplifier, although these are very simple. the reversal of current in the filaments, get an amplifier into operation so that the The rheostats should be turned to the since for a small fraction of a second the whole family can enjoy the broadcasting. "full on" position and the entire filament filament current falls to zero and then He can still use his headphones when he's adjustment of the audio amplifier tubes comes back the other way, as the 60 -cycle after DX, but for fairly short range recep- done by the rheostat on the supply unit. A. C. reverses itself 120 times every section, a loud speaker will suit him much Then, the two grid return leads from the ond. This varies' the plate current better; for after all the headphones are a "F" posts of the two audio transformers slightly, but the effect is not trouble - rather selfish proposition unless you have' are connected to the negative terminal of at all. four or five sets of them. a 4/ -volt ''C" battery, the positive side Yet, there are numerous listeners who of which is connected to the minus "B" Avoid Grid Induction don't want the trouble of caring for a battery post and to the arm of the poten- Therefore, any noticeable hum is storage battery and perhaps don't wish to tiometer. The negative "B" post is dis- caused by induction between the filament spend $15 extra for a battery charger to connected, of course, from its usual posi- wiring, which carries alternating current, avoid the inconvenience of carting the oat - tion on the plus side of the "A" battery and the grid or grid return leads. This tery around to the service station every wiring. means that special precautions must be now and then. But, unless dry cell tubes It is assumed that a separate battery is taken to keep them four or five inches are used, such an amplifier requires a used for lighting the detector tube, since away from other wires in the set, and to sto: age battery, and at best, the dry cell alternating current cannot be employed make them as short as possible besides. tubes can scarcely compare with If any A. C. induction affects the larger tubes for volume output. grid, the amplification constant of the tube (about 7 or 8) will Alternating Filament make the noise a whole lot louder. Current Ordinarily, the grid return leads However, it is now possible to are run to the negative side of the secure equally good results with- filament to secure the necessary out employing a storage battery, negative grid bias for clear am- providing you have alternating plification. Here, however, the current supplied for lighting and filament's poliarity changes con- electric power in your home. tinually, so a "C" battery is used Through the use of a simple trans- to get the negative bias. If the former which may be had any- positive of the "C" battery were where, the necessary filament now connected to either end of current may be drawn from the the filament wiring, there would lamp socket at scarcely any cost. be a very strong hu min the speaker. This is due to the fact HE photograph shows a power that every time the grid is supply unit comprising this charged positively by the voltage transformer, a 30 ohm rheostat at the end of the filament, some A to secure filament for an audio ampli- and a potentiometer, from 200 to unit arranged electrons are drawn to the grid lighting The 400 ohms resistance. The parts fier from the alternating iurrent socket. and it thereby reduces the plate by which are mounted on a regular radio panel measures 7x10 inches, and the instrument current a great deal. In order to panel, with three outlet binding the correct voltage is obtained is a toy transformer. avoid this alternating charge on posts. Two of them are for con- the grid, it would be necessary to nection to the filament circuit, while the the wiring for an audio amplifier which connect the grid return lead to the center third is connected to the movable contact may be mounted with the rheostat and point of the filament, inside the tube. of the potentiometer. potentiometer, but for which the toy Any department store with a good sized transformer is laid on the floor or shelf situation is similar to that of a toy department, or any large electrical under induction between the grid leads THEman walking up and down a large supply house has the toy transformer in and the filament wires or the transformer see -saw. When he stands at either end. stock. The cost will be between $3 and itself. The transformer should not be he is bumped up and down a great deal; $4.50. depending upon the make. There mounted in the amplifier cab'net. the nearer he gets to the middle, the less should be adjustable means for securing he's jolted, and finally right at the center is various voltages for lighting the filaments. THE audio amplifier wiring quite of the board, he doesn't go up and down jack is shown and if the output voltage is between 6 and standard, although no at all. But since it's physically impossible for the second stage, it being assumed that 12 volts, the proper amount of current can to make that center connection, we shunt if phones are used, the amplifier will be easily be applied to the two amplifier tubes a potentiometer across the filament and rheostat. UV201 -A turned off altogether, but that if the loud through the 30 ohm run the grid return lead to its movable or C301 -A tubes are used. speaker is employed. both tubes will be This is placed the electrical In case you may wish to try smaller necessary for sufficient volume. Special arm. then at tubes than these, the transformer chosen precautions should be taken with the grid center of the winding, or at the center of should supply lower voltage, perhaps 2/ leads and the grid return wires. These filament resistance and the A. C. hum is as a minimum. To use the A. C. filament must all be short and carried above or nicely balanced out. supply with an amplifier already com- away from the filament wires. A separa- Preventing Tube Danger pleted, mount the parts as in the tion of four or five inches is desirable. photograph and wire them together in There is a very slight hum caused in the It is usually necessary to connect the accordance with the section of the circuit speaker, but this is much weaker than the ground to the negative "B" battery bind- diagram to the right of the dotted line. actual carrier wave noise of the broadcasting post of the amplifier, in order to This includes the rheostat, the potentiom- ing station itself, and the faintest sounds ground the central balance point of the eter and the toy transformer. of speech and music drown it out imme- potentiometer. Care must be exercised in RADIO AGE for August, 1924 The Magazine of the Hour 31

30 or,As RHEOSTAT (T

AUDIO A v0 0

C " BATTERY

POTENT/C :'PETER 0 O RECE/VER B e T72-0' LOWOtSOEi9!«/2 BF Complete wiring diagram of a two stage audio amplifier with filament-current from the lamp socket. Ninety volts of "B" battery are used, with -a potentiometer and 4/ volt "C" battery to eliminate the A. C. "hunt." first lighting the tubes to use a combina- The A. C. system is bound to come into through practice with the use of A. C. is tion of binding posts and switch lever ad- wide use shortly, because it can be applied the one who will first succeed in cutting justments on the toy transformer to give to radio frequency tubes also, by a similar his battery upkeep expense to about one - a voltage of about 6 or 7, to prevent dan- treatment of the grid return leads. More- tenth or less of its present cost. The A. C. ger to the tubes. The rheostat should not over, it is now coming into use for deliv- is always on tap, never runs down, and is be turned on farther than is necessary for ering plate voltage, too, when used with a used for filament lighting at a cost of less good volume and clear results on the loud proper rectifier and filter system. Hence than $2 a year, even if the set is used speaker. the man who starts in to become familiar three hours a day every day in the year The Importance of the Loud Speaker By WILLIAM CULLENS Not long ago, when broadcasting was the solenoid principle, in which the cur- gap is constant and fluctuations of cur- more or less of a novelty, it was common rents act on a coil placed in the field of rent through the windings of the loud with many enthusiastic experimenters to a strongly energized magnet. speaker does not change the impedance entertain their friends with a radio con- The first and second types of loud of the circuit. The DC current from the cert. After the loud speaker had been speakers are excellent in their own limited B battery does not act on the diaphragm induced to operate, the congratulations way; however, there are a few serious of loud speakers such as the Thorophone of the guests were made with effort, the faults that entirely prevent them from and less distortion may be expected. more candid of the critics declaring that being considered as first class loud speak- At the same time the third type of re- if the barnyard chorus coming from the ers. One is that they cannot be used on producer will not rattle or "freeze" on horn was radio, they would be content very strong signals without causing the extremely loud signals, yet will give a with a phonograph. diaphragm to strike the pole pieces of the greater amount of sound on extremely There were many fans, it is true, who small fixed magnet and produce a rattle weak or faint signals. A mica diaphragm overlooked the obvious imperfections in in the loud speaker. one of the most perfect substances known the reproduction of the human voice. Another serious limitation to this class for sound reproduction, is used, whereas The marvelousness and mystery of radio of loud speakers is that when high B bat- in most of the other classes of speakers itself was quite sufficient to outweigh any tery voltages, such as are common in a metal diaphragm must be used, resulting shortcomings of the loud speaker. Re- most audio frequency amplifiers, are used, in a greatly inferior tone quality. cently the demands have become more a DC current flows through the windings The particular shape of the horn has critical, and the radio public have been of the phone and exerts a strong down- a great deal to do with the performance insistent that the loud speaker should ward pull on the diaphragm. This causes of any loud speaker. From a theoretical not be the cause of imperfect reproduc- the metal diaphragm to be drawn out of point of view, a straight horn is better tion. shape and will cause the loud speaker to than a curved one, and the amount of In its present usage, the term loud have a hollow or tinny sound. increase in the size of the horn in propor- speaker is applied generally to electro- tion to its length must be very carefully phonic devices employing some means of Impedance Shouldn't Vary calculated for best results. When this is distributing sound over an area. It is The vibration of the metal diaphragm once obtained the horn can be curved into possible to divide loud speakers into three toward and away from the poles of the most any shape without destroying its sephrate and distinct classes, however: magnet in the unit will cause the air gap amplifying value or tonal qualities. 1. Those which make use of existing to vary. This, in turn, will cause the im- The material of which the horn is corn - telephone receivers by means of rubber pedence (alternating current resistance) posed of is very important in regards to connectors or clamps to attach a pair of of the loud speaker to vary and has a the quality of music that will be received, phones to a horn. great deal to do with the proper oper- and with the faithfulness with which the 2. The type of speaker that uses a ation of the receiving set itself on weak sounds are reproduced. A horn made of single telephone receiver equipped with or distant signals. The impedance of the wood or paper mache gives a purer tone a cap to permit its being fastened to the loud speaker has its function in the tun- than a metal one, which is liable to pro- small opening of a horn. In this class ing and balancing of the receiver, and if duce brassy overtones or vibrations. can be included the numerous loud speak- it is fluctuating, will have its effect in up- Horns made of some inert material and ers that incorporate a telephone of some setting the accurate tuning of a receiver. which will not vibrate or absorb the sound sort in the base of the horn. The third type of loud speaker this waves, have been found to be the most 3. The loud speakers constructed on factor need not be considered as the air satisfactory for loud speaker use. 32 RADIO AGE for August, 1924 The Magazine of the Hour

New French Theory Opens Way to Solution of Static

P\RIS :- General Ferrié and Monsieur actually to suppress a period of static way on the ground. Gradually they R. Bureau have just completed a arising from the previous prevalence of equalize themselves either by the mixture most interesting study of the occur- the cooler polar winds. of the two currents of air or by the trans- rence of static disturbances -the so- called The electromagnetic disturbances -that fer of heat energy from the warmer air to "atmospherics" - and of their possible is, the static -are parallel in every way the cooler. This explains the effect of a causes. The result is a novel theory of with the more familiar meteorological dis- warm, equitorial current in causing a the air currents in the atmosphere; a sug- turbances such as hot waves, thunder- decrease in static. The warm air arrives, gestion that is perhaps the most im- storms, and the like. The cool polar winds usually, at a high level in the atmosphere. portant contribution made so far to the bring on these disturbances; the warmer It mixes slowly with the underlying cooler explanation of static. winds from the equator are calming and air. As it does so the disturbance in the The new theory is already the focus of quiet. atmosphere is decreased; the "front" be- active discussions among French scien- tween the two air currents becomes less tists and radio amateurs. It seems certain marked and the static disturbances die that it will play an important role in the Technical Expert Will away. study of static everywhere; a study now The reverse case can also occur. When- actively under way all over the world. Send Radio Data ever a mass of cold air sweeps down over The outstanding conclusion from the From France France from the Northwest toward the observations collected and analyzed by Southeast (which is the usual direction of C. R. Bluzat, formerly technical General Ferrié and Mr. Bureau is the editor of RADIO TOPICS and at such currents in France) great atmos- close relation between the occurrence of present a special technical writer pheric disturbances are produced, with static and the presence of currents of cold for RADIO AGE, is in France vis- accompanying interference with radio. air above the great mountain region of iting relatives and studying the These disturbances become more pro- the Alps. latest developments that country nounced as the cold air approaches the During the Winter the correspondence has made in the field of radio. Alps and is forced to rise to higher in time between these Alpine air disturb- M. Bluzat is a native Frenchman altitude. ances and the onset of static is practically and is thoroughly familiar with In this way General Ferrié and M. perfect. In the Summer the results are both American and French radio Bureau have been able to trace the static more complicated. The static seems to circuits. In the September RADIO produced by individual "fronts" of cold AGE his first article on the latest air in their progress across France from come then from every direction at once. steps in French radio science will be published, approaching the sub- the northwest coast clear lo, and even Cold Air Not So Disturbing ject from an authoritative technical across, the Alps. This is explained, the French investiga- angle. tors believe, by the fact that currents of M. Bluzat's article, along with radio fan knows that static is cold air do not cause so much disturbance those to be published next month FVERYextremely prevalent in mountainous in the atmosphere during the Winter as by Frederick A. Smith, editor of regions. The new investigations give the they do in the Summer. The difference RADIO AGE, who has been in first real evidence as to why this is so. between them and the main mass of the Europe making a radio survey for They provide, in addition, the first con- will give atmosphere (all of which is then cold) the past two months, sistent theory of the hitherto mysterious "The Magazine of the Hour" a relations between radio disturbances and is not so great. truly distinctive foreign radio department second to none. the weather. Hot weather means much ACCORDINGLY, during the Winter it static because it is usually a time of is only in the much confused atmos- intense atmospheric movement and mix- phere over the Alpine regions that the air ture, at least in a part of the country. disturbances are great enough to produce The Source of Trouble important amounts of static. In other sea- The chief place of disturbance is the "Fronts" Help Static sons the atmosphere as a whole is warmer. plane of contact -what is called in French Again, the supposed relation between Cold air currents disturb it everywhere. the "front" - between a mass of cold static and the occurrence of areas of high Much static is produced, therefore. in all Northern air and one of warm Southern barometric pressure may be due not to districts. air. Such a "front" is the seat of ex- any effect of the air pressure itself, but to The observations also bring out the fact change of a large amount of energy; both the fact that high -pressure areas are fre- that in the latitude of France the occur- gravitation and electrical. The gravita- quently surrounded by one of General rence of static is favored by the preva- tional energy is expressed in upward or Ferrié's "fronts," that is, by a region of lence of cool winds coming from the polar downward currents of great masses of air. contact between a central mass of warm regions. On the other hand, the warmer Such "fronts" between hot and cold air and surrounding masses of cooler air. air currents that come from equatorial masses of air may exist high in the atmos- Wherever warm air and cold air meet regions not only yield less static but seem phere without being perceptible in any and mix there is in active exchange of RADIO AGE for August, 1924 The Magazine of the Hour 33 thermal energy. A part of this energy Eiffel Tower on Short Wave were heard. seems to be translated into electrical The Eiffel Tower is now calling America To simplify the notices which are com- energy; to be expressed either in thunder- on the short -wave telegraph set which ing in in many different languages, Cap- storms or in static disturbances or in both. they have recently installed at this big tain Bergeron has devised the following The ultimate origin of static, like the ulti- station. The Tower commander furnishes code to be used by hearers reporting to mate origin of our weather, seems to be a monthly schedule of transmissions. him: the fact that the poles of the earth are Transmissions take place every Mon- cold, whereas the tropics are hot. day, Tuesday, Friday and Saturday. R 1- Signals unreadable. Transmission will be on 25 meters. R2- Reädable with great difficulty. World's First Tri- Lingual Station The transmissions will take place at R3 -Weak but readable. intervals as follows, according to the R4- Readable. Fans who receive broadcasts from Can- following table: Comfortably readable. ada's premier radio station are familiar R5- with the fact that all announcements are R6- Readable quite strong. 5:00-5:10 A. M.-f f f f f Signals strong. made in French and English. 5 : 1 5 -5 15 A. M.-h h h h h Ri- 5:30-5:40 A. M.-f f f f f R8- Signals too strong. Soon a third language will be added: 5:45-6:00 A. M.-h hhhh "La Internaciona Linguo " -Ilo, the per- 3:00-3:15 P. M.-f f f f f R9 -Loud speaker. lan- 3:20.3:35 P. M.-h h h h h fect radio auxiliary international 9:00-9:15 ,P. M.-f f f f f guage-simple, neutral, harmonious, flex- 9:30-9:35 P. M.-h h h h h ible, expressive, logical. British Plan Radiophone Plant Jacques N. Cartier, director, and his These times are Greenwich mean time, Following a demonstration by the offi- staff of announcers and story tellers are which is five hours earlier than Eastern cials of the American Telephone and Tele- studying Ilo and find it extremely easy standard time in the United States. Local graph Company and the Radio Corpora- to learn. times, daylight saving time, etc., may be tion of America, by which radio telephone By the time the speech was trans- new big plant of mitted for t w o CKAC has been hours from New installed, every- York to London, body connected the British post - with the s t u d i o office appointed a expects to be able committee to in- to talk Ilo, and vestigate trans- then this musical Atlantic telephony. "tongue" will be This committee oti the air regu- has recently rec- larly. ommended t ha t Heretofore t h e British post- CKAC has found office establish a bi- lingualism ade- 200 k. w. radio quate for its needs, telephone plant at but now that con- their new r a di o stantly increasing station at Rugby, numbers of radio England. enthusiasts are The committee clamoring for Ilo recommends that -"Well, n o t to this plant be of a advance is to re- t y p e similar to cede," according that which has to J. N. C., "and been used by the in Ilo all fans have American Tele- a new standard! phone a n d Tele- There is no way graph Company possible for us to and the R a di o Satisfy everybody. Corporation of All non -English America in t h e and French fans, experiments which within our range, they have been advocate Ilo, be- THE CANADIAN CASTLE OF JAZZ carrying on for the cause it is the only American Radio fans who tune in on CKCH at Ottawa, Canada, and roll up last eighteen known auxiliary the rugs for the peppy dance programs this station broadcasts, will be interested to months in trans- language possess- know where the alluring music originates. Above is shown the "Chateau Lanier" mitting speech ing complete Hotel, near Ottawa, which is connected with CKCH's studio. Popular programs across the Atlan- r a di o , scientific pleasing to Americans and Canadians alike are broadcast from the Chateau tic. a 435 and business vo- Wednesday and Saturday nights on -meter wave length. If this work is cabularies." carried out, it is Mr., Cartier points out that CKAC computed from the relation of these times expected that under favorable atmos- serves a big Italian colony, a Greek vil- to Eastern standard time. pheric conditions during the w in t e r lage, a.ti,. i iniature Yateeland, a tiny The text which is being sent by the months, it will be possible to connect tele- Chinese town, a large Jewish settlement Tower is simply: "v. Ni. v. de FL-FL- phone subscribers in the United States to and several other small colonies, whose 115 metres -emission f f f (or h h h)." telephone subscribers in London, and in inhabitants speak Polish, Roumanian, This text, of course, in code is being this way permit them to talk to each other Russian, Galician, Ukranian, Dutch, Swed- transmitted very slowly, just as above; as they do over ordinary telephone cir- ish, Norse and twenty other languages, not, it must be remembered, in English. cuits. In doing this the subscribers at besides the two big majority French and The commandant of the Tower, Cap- each end would be connected to their re- English- speaking nationalities. tain Bergeron, has asked all American spective radio stations by the wire tele- Because they do not know French or amateurs who pick him up to please notify phone lines. Atmospheric conditions, English, foreigners are sore and irritated him of the relative intensity of the "fff" however, vary tremendously from winter in spirit and constantly chafing under the and "hhh" signals, as well as of the atmos- to summer and during the different hours restraint of language barriers. pheric conditions under which the signals (Continued on next page) 34 RADIO AGE for August, 1924 The Magazine of the Hour of each day. To determine the effect of such atmospheric changes, the engineers of the American Telephone and Telegraph Corn - pany have been transmitting speech weekly from America to England, measuring static interference and the strength of signals received from a number of British telegraph stations. The British postoffice has been carrying out careful measure- ments of the energy which they receive under various conditions from the telephone transmitting station in America, and also from certain telegraph stations. The tests which will be possible when the British transmitting station is completed will form another important step in the work which has been carried on for many years in the development of radio telephony across the Atlantic Ocean. The first successful telephone transmission across the Atlantic was in 1915, when engineers succeeded in talking by radio telephone from the United States Naval Station at Arlington, Virginia, across the Atlantic to Paris, while the same messages were heard 5,000 miles to the westward at Honolulu. Amateur Arrested for "Talking" to U. S.; Vindicated The decision that it is not a serious offense against law and order for an experimental radio amateur of Holland to communicate with amateurs in this country has done much to vindicate the standing of amateurs in the Netherlands, according to a report received by the American experimenters. Soon after a prominent French telegraph amateur was decorated with a gold medal for the skill with which he com- munciated across the Atlantic Ocean on short wave lengths, amateurs in Holland were regarded as something equivalent to the boll weevil. The authorities were inclined to classify them as a menace to their community. HE WINS THE BROWN DERBY Photo from Intl. The science of private radio communi- And he isn't ashamed of it, either. F. H. Schnell, traffic manager for the Amer- cation among the youths of the country ican Radio Relay League, is shown wearing the brown derby awarded by Kenneth had kept abreast of progress much better B. Warner to the first American amateur to establish two -way communication with a European operator. Mr. Schnell swept aside all derby opposition when than the laws, with the inevitable result he conversed with French 8AB. that H. J. Jesse, Jr., prominent radio experimenter at Leiden, was made the defendant that the courts might decide Broadcasting in South Africa Soon transmitting set will be used. whether it was lawful for a citizen to Although not actually granted, the Gov- The Associated Societies' license gives transmit. ernment has finally definitely promised a them an area for the collection of fees It was charged that Jesse's telegraph broadcasting license to the Associated from listeners extending 100 miles in all and telephone station was not intended for Scientific and Technical Societies. Johan- directions from Johannesburg and it is public communication and that messages nesburg, for a broadcasting station to be expected that the station will be sup- had been exchanged "without authority installed in that city, Consul G. K. ported by the fees paid in by persons having been obtained from the minister Donald reports. The reason for the delay owning receiving sets. of Waterstaat." He had in fact taken has been an objection lodged by the The program for broadcasting includes, part in transatlantic radio tests and com- Johannesburg municipality on the ground in addition to musical entertainments, municated with amateurs in the United that the city was the proper authority to talks of interest to women, market re- States as far west as Nebraska. exercise broadcasting rights. The objec- ports, local news and a children's hour. The attorney for the defense pointed tion has now been overruled. When the Application has been made to the Para- out that regular telegraphic communica- license is issued, it will be only a matter guay Chamber of Deputies by Messrs. tion in competition with commercial of a few days before broadcasting is Eduardo Rojas & Compania of Asuncion traffic was not intended and that the case commenced. for a concession giving this company ex- was in the class with work concerning It is announced that the new station clusive rights to sell radio telephone laboratories. The clerk of the open min- will be installed on the top of the Stutta- equipment in Paraguay for five years. It istry congratulated the defendant for ford Building, with a broadcasting studio is said, Consul D. A. Wilson reports, that having communicated with a station in located on the third floor in the same Mr. Rojas has already obtained the neces- America. It was shown the defendant had premises. The wave length has not yet sary equipment for broadcasting and will not transgressed and the case was been definitely settled upon, but it will place it in operation within six months if dismissed. be between 350 and 450 meters. A 500 -W. the concession should be granted. RADIO AGE for August, 1924 The Magazine of the Hour 35 "Big Things Are Coming for Radio on the Farm" By GEN. JAMES G. HARBORD itADIO'S greatest opportunity lies in but you may pluck their syncopations instant advice on prevention and treatment its usefulness to the farm. I believe from the air tonight, and on many another even to the most remote localities. Radio that radio broadcasting is destined night if you wish. will tell you how to fight insect pests that to become a greater boon to the farm The nearest agricultural college, the one are devastating your crops. than to the city home. It can be made a that knows most about your own peculiar The radio telephone also will be able thing of greater benefit and more practical local problems, will be brought into your to broadcast calls for farm help for dis- use to the thirty -nine millions of you who little sitting -room of an evening to help tricts in which labor shortage exists. If, live on farms than to the rest of us who guide you in tomorrow's farm work. The because of a sudden change in weather, live in cities. And this very soon. general educational and entertainment lec- crops are spoiling in Kansas while men Those of us who are trying to direct tures of the Chautauqua type need no seek jobs in Nebraska, a veritable labor this gigantic new industry that has sprung longer wait upon Summertime and the big army could be started for the Sunflower up overnight have been thinking about tent. State overnight. the farmer's problems and his needs - If you live in Nebraska and have a load about how radio can be made to serve of hogs to ship to market, you can know WE WILL try to make radio give you bim. We have just completed some nation- the quotations up to the last minute on just the kind of service you need - wide inquiries on the subject of how radio the Chicago market -by radio. The news- at the time when you need it most. can help the farmers. We have asked Wireless can help link up government questions of thousands of farmers, school- services direct with the farm. It will be- teachers, agricultural professors, farm come the servant of the various farmer paper editors, farm agents, Grange offi- co- operative movements. In one state cials, country editors and bankers. where there are two hundred Grange halls arrangements are being made to ORDINARY common sense tells me place receiving sets in each hall. Someone what a blessing radio can be to the has pointed out to us that by use of radio farm; but the unanimity of the evidence broadcasting Farm Bureaus could get their which our national inquiry brought us was information and proposed policies into the amazing. hands of individual farmers "with the Consider for a moment the amazing speed of light." Grain elevators and live- growth of the radio broadcasting industry stock shipping associations can get market as a whole. information instantaneously by wireless. We point to the automobile industry as That is almost a literal use of the word having experienced an amazingly rapid instantaneous. growth. In about twenty -five years the The spread of advanced farming meth- motor has come into such general use ods through the teaching of agricultural that there are now 14,000,000 automobiles colleges has added hundreds of millions in the country, or two for every three to farm productivity, and yet only about homes in the country. But radio broad- 150,000 students are enrolled at these casting is only two years old and already colleges at any given time. Faculties of there is one radio set to every seven agricultural colleges are aroused to the homes! tremendous magnification of teaching op- We have been riding in auomobiles for portunity which broadcasting gives. One so long that we have forgotten, almost, has suggested that the farmer be given a the day of the horse -drawn carriage, while wave length all his own. This sort of a it was only day before yesterday, one teaching program is being worked out: might say, that we learned we could have Illustrations and charts and textbooks to an inexpensive radio telephone in our be sent by mail, instruction and guidance homes. Yet as against 4,000,000 cars regarding the studies to be by radio lec- made last year for us, we bought and tures-a great radio extension university, constructed 2,000,000 radio sets. in which hundreds of thousands will be The phonograph had a startlingly enrolled and work at home, to travel to abrupt leap into popularity. The Depart- their alma mater only on completion of ment of Commerce estimates that we have the courses, when they go to receive a spent a little less than $150,000,000 in a diploma. year for phonographs and records. We Personally I believe that radio develop- . ment is going to continue at such a rapid estimate that "radio fans" spent $150,- Photo from Fotogram. 000,000 last year for sets and parts. YOUNGEST BROADCASTER pace that in a period of three to five years Of the 3,000,000 radio sets now being That's the distinction enjoyed by little it will be possible for one man to speak to used in the United States we estimate Harriett Carman, daughter of Harry H. 50,000,000 persons in the United States, that only about 150,000 are on the farm. Carman, at 2 E L. She is only .4 years and to many millions in Canada, South old, but air Although farmers constitute a third of she's on the frequently and America, and Europe, if stations there is rapidly becoming known to radio fans relay his voice. the population, they are as yet using only all over the country. The picture shows one twentieth of all the radio sets in her at her father's broadcasting appara- We believe that there will come to be existence in America. There is only about tus at Freeport, L. I. perhaps three of four great super- broad- one set to each forty farm homes. casting stations. :;.sse then can broad- paper will not get these quotations to you cast identical programs by retransmission YOU will soon sit in that familiar living - until many hours later. This of course is from one station to another. With such room in the old farmhouse and hear a fact of the present, and no forecast of technical resources at their command, the President and others speak, enjoy radio future. consider what wonderful programs such Grand Opera as thoroughly as the thirty - Soon we shall be able to render great a national entertainment institution could two hundred who actually have found service to agriculture by broadcasting provide. seats in the Metropolitan Opera House in weather warnings that have a bearing on I like to visualize what radio means by New York. Paul Whiteman and Paul the care and shipment of crops and farm thinking of the boys around the grub Specht, the jazz kings, have come to you stock. In periods of epidemics, such as wagon at round -up time on some far already as stars of the phonograph record; hoof-and -mouth disease. radio will deliver (Continued on page 48) 36 RADIO AGE for August, 1924 The Magazine of the Hour

Only a Short Time Left to Q-et the

Best Hookup Book Ever Printed !

The profound technical problems to be encountered in the study of Radio are all very Full of Hookups That Are interesting to the expert, but the great major- ! ity of "fans" are vitally concerned in the Guaranteed to Work building of simple sets that really will work The RADIO AGE ANNUAL for 1924 is and produce effective results. chock full of real radio ideas. From the humble $6 crystal receiver to the great engineer- To supply this demand for practical, sim- ing problems involved in the Grimes Inverse, ple and efficient sets, RADIO AGE compiled Neutrodyne and Super- Heterodyne sets, the THE RADIO AGE ANNUAL for 1924 in fan is taken by easy and successive stages the belief that it more real through the various steps in radio construc- contains help and tion. meaty material than any other book on this subject ever published. The principal articles are illustrated with the well -known RADIO AGE isometric draw- THOUSANDS have been sold at $1 each ings, reputed by countless experts as the since they first clearest construction diagrams ever put on the were offered to fans early this market. year. The supply is rapidly becoming ex- hausted, so we are making this last appeal to The construction of every standard set and the fans to order their essential accessories is described in detail in ANNUAL now if they the ANNUAL. Each tuner and each acces- have not already clone so. sory was built in the RADIO AGE laboratories and tested and proved before it was Is awarded space in the ANNUAL. This Book Endorsed by You cannot afford to be without this won- Expert and Novice Alike derful radio "guide book." Send your dollar today for this gold -mine of radio ideas.

Cover View of 120 -Page Annual. here This Coupon, Pinned to a Dollar Bill, Will Bring the ANNUAL to You by Return Mail! (If by Check, Add 5c for Exchange.)

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ROUND the world by radio! IS THE American Society of Composers, Authors and It sounds impossible, and yet scientists are talk- Publishers weakening ? We have heard several broad- ing about it without cracking a smile. In fact, casts of popular copyrighted music recently from stations they are devoting the best part of their lives to determin- who do not pay levies to the Society. These stations are ing just how and when radio will be sufficiently harnessed próceeding on the theory that one court decision against and organized to allow Mother Earth to be the universal the Society is enough to throw out its contention that it is playground of the ether waves. a crime to broadcast copyrighted selections over the ether Heretofore radio transmission of 4,000 miles was con- without a permit. As many fans will remember, an sidered miraculous and the height of radio development. Ohio Supreme Court judge ruled broadcasting is not a Devotees of the science settled back with the air of a public performance for profit and therefore does not person who has seen all there is to see and expects to view come under the jurisdiction of the copyright laws. We no more. But no sooner was this "last step" announced are elated to hear that the Society is at last realizing the than the next step was under way. futility of its fight against the broadcasters and the lis- Readers of RADIO AGE who have been keeping tening public. Our only hope is that the broadcasters themselves informed on latest developments will need no will not decide they can get along without the Society's explaining as to the real situation. They know efforts compositions and refuse to render them altogether ; for are being made to get every big country in the world to then the Society will have lost the greatest agency it ever become a part of a great chain of short wave radio sta- had for the free popularization of timely tunes. If noth- tions whose sole duty will be to relay programs around the ing else, the war between the broadcasters and the music world on special, prearranged wave lengths. publishers has resulted in the birth of a new coterie of The United States already has the beginning of such a music writers whose work is becoming more popular than

"radio . chain." Powerful stations are well sprinkled the so- called popular copyrighted brand. throughout the country so that with a few weeks' prepa- O rátion, America's part in the world -wide transmitting B ®O6 =9 program could easily be taken care of. A few other nations, including Great Britain, France, Germany, South NE BIG broadcasting station reports that there has America and Canada, have one or two giant stations, but been a decided trend toward increasing classical they are not yet fully developed. music in recent programs. Asked why, be reports that All that remains is the final word which would set all the demand came from the public itself, who, contrary to radio forces in action to complete this international pro- common belief, was fed up on jazz and wanted something gram of radio broadcasting. soft and soothing. Perhaps we can take this as an indi- The answer lies in an international radio conference. cation that radio is becoming a barometer of the national. Radio as an industry and as a science has far outgrown mind. If so, are we becoming more serious and even - the limitations originally placed upon it. It is too big to minded, and getting over the. flapper -and -sheik age that: be controlled as each nation sees fit. There must be preceded radio's entry into the schème of human events? international radio co- operation or radio will stand still Maybe so. Watch radio programs and judge for yourself. realm of magic just when it should forge ahead into a new m accomplishments. G=1= DOO ®O The United States has taken the lead in peace and armament conferences: Why not in radio? This coun- GENE McDONALD, president of the Zenith Radio try has developed radio more than any other, and has Corporation of Chicago, has a fine idea. He sold shown the most liberal attitude concerning the use of station WJAZ because he believed it interfered too receiving sets by the general public. much with local broadcasting, located as it was in the Then why should not America assume radio leadership heart of a big Chicago residential section. Mr. McDonald by calling this radio conference? Secretary of Com- now proposes to find a location a hundred miles or so merce Hoover has shown the right spirit by calling a con- from the city, where he can build an isolated broadcasting ference of those interested in radio in this country; but station which would not interfere with reception of other he should look farther and invite foreign nations to share stations any more than reasonably possible. The studio in the long strides America is taking in the once "infant would be located in the city, connected with the station by industry." telephone. If this country had more liberal -minded men If it can obtain a willing and influential listener among like Mr. McDonald, the ether wouldn't be so clogged with the government officials interested in radio, or among unnecessary wave lengths and those stations which had prominent radio manufacturers, RADIO AGE will be so to exist wouldn't do so at the expense of exasperated bold as to offer a tentative constructive program for such neighbors. Mr. McDonald's experiment, if successful, an international radio conference. This proposal should ought to open a new era in broadcasting. be especially welcome at this time, because of its proximity 0 to the Radio World's Fairs in New York and Chicago. a a . ®o a ®o Correspondence from readers is urgently invited. Every broadcasting station should be interested, RADIO MOVIES ! Will wonders never cease? In especially in view of the fact that the government this issue you will read how radio motion pictures has begun to weed out "dead wood" among the have become an accepted fact in experiments in Wash- broadcasters. Eighty -two stations were shut down ington, D. C., and it is now only a matter of time before last month alone. Is this not proof enough that only the fan may equip himself with the proper apparatus. those who produce the best service to the fans will Telephone pictures first, then radio pictures ; now radio survive in the future? movies. We refuse to predict the climax of it all. 38 RADIO AGE for August, 1924 The Magazine 7.1. the Hour ,<;,`z, Pne%r.ZZaS

r! a G'1Ì J,8 Hook'.'iips 1,,s ,-px° our / leLrdPrs

The material appearing under the title "Pickups and Hookups by Our Readers" in RADIO AGE, is contributed by our readers. It is a department wherein our readers exchange views on various circuits and the construction and operation thereof. Many times our readers disagree on technical points, and it should be understood that RADIO AGE is not responsible for the views presented herein by contributors, but publishes the letters and drawings merely as a means of permitting the fans to know what the other fellow is doing and thinking.

WE ARE quite sure that Many of to the radio world as a whole. Under the publication as one that is difficult to read our new readers, in scanning over direction of the Pickups Editor, letters, and poorly executed. the July issue of RADIO AGE, lists, circuits, challenges and other inter- Lists of stations heard containing trans- will wonder just what the Pickups by esting matter is published. You can feel Pacific or trans -Atlantic receptions should Readers section of this magazine is, how the wave of good fellowship that this cold preferably be confirmed. Your contribu- to contribute and what our purpose is. type and paper radiates as you read over tion always is twice as convincing if you At the time we learned that RADIO the varied items of interest. can say, "the reception was confirmed." TOPICS was to be absorbed by RADIO Contributions to the department áre Incidentally, if you are contributing a cir- AGE, our July copy had all gone forward always welcome. Any items of interest cuit or other matter of technical nature it to the printer, and we therefore lost our with regard to lists of stations, results, is a wise plan to omit no details; too many chance to welcome that group of readers information and other items are solicited. of our contributors have been swamped who formerly used to refer to RADIO Information with regard to experiences with questions. Witness the letter of M. C. TOPICS for all their radio news and with different types of receivers is espe- Williams, a contributor to the June issue, information. At any rate, though we are cially desirable because it shows the other in the department this month. He says a little late, we want to extend to these fellow just what you have done in cases he got 1,180 letters since that time. Make new friends our heartiest welcome and which are much like the ones he may be your descriptions as complete as possih'e. assurance that their contributions are as experiencing. The purpose of the Pickups Pages I am welcome as any others. We know that Contributions should be neatly executed sure can be gleaned from the contributions they will have a different perspective of and, if possible, written on a typewriter; that follow. All in all, we have built up this department, and may have some con- or if not, should be neatly done in pen a hearty, good- natured following of reld- structive criticisms, too, to offer. and ink. Pencil contributions may look ers, and we have all kinds of fun in this Briefly, the Pickups Pages are a group all right when you've just finished writing department. of pages devoted to the contributions of them, but you should try to read them We're glad to meet you. We hope you'll all our readers in general. In this depart- after they have been handled a few times. like our department, and we hope to ment, fans avail themselves of the chance However, all we expect is that you make include some of your contributions in the to compare results, circuits and informa- them as neat as possible, because a neat next month's department. tion, and contribute anything of interest letter always has twice as much chance of THE PICKUPS EDITOR. The first of our contributions this month is a gathering of additional mate- SHORT rial on the Superdyne by M. C. Williams, AER/AL who asks help because he seems to b: overwhelmed by mail. We're always will- OUTS/DE ing to help our contributors out. so here TUPM CUS 52 7VRNS goes: ovrs,or GCO ?5 RADIO AGE, TURNS Gentlemen : Due to numerous letters I am receiving in the daily mails asking for technical data relative to the Super - /5 dyne receiver, as published in the 7T/RNS RADIO AGE for June, I suggest you e print the following additional compiled technical data which is re- by the majority: fXEO quested p02 (A) It has been found that a five - VERNIER tube Superdyne using one stage radio 04E0 5171r frequency, detector, one stage audio /6/2 coupled frequency and VOLTS transformer 207- the push and pull (two -tube) stage, gives all around better results as to clarity, about the same range, and affords a saving in both "A" and "B" batteries. Also not much difference GOOD I in volume. G7UND (B) The Superdyne ranks next to Ultradyne and of the Baby Heterodyne receiver constructed with spiderweb the Superheterodyne. Figure 1. The diagram multi -tube circuits, in the order coils as it was submitted to us by Mr Lueven of Los Angeles, California. other RADIO AGE for August, 1924 The Magazine of the Hour 39 other multi -tube circuits, in the order will tone down static considerably a 6 to 1 in first stage and a 4 to 1 in named, possibly next to the Super - and will nearly cut out AC hum and second will be better. Het, according to number of tubes, other foreign battery interference. 3. A fixed condenser suitable to to volume and clarity of tone. This may be added and wired so that your present antenna placed in series (C) The small fixed condensers it may be cut ólit with a neat fila- in aerial lead is better than a variable. as shown in the June RADIO AGE ment switch installed on the panel. This must be arrived at by trial. may be done away with, connected (13) A variable grid- condenser 4. It is not necessary to have rheo- as they are across the primaries of (grid -denser) is also very essential stats for each tube, but they help to the audio transformers, for they are and is certainly worth installing in get the best there is in each tube, for seldom needed. place of the .00025 fixed grid con- the characteristics of tubes vary. One (D) An 11 -plate condenser condenser. good rheostat for detector and one nected in series with antennae lead (14) Vernier or micrometer ad- for radio frequency seems to meet all wave length justed condensers are not needed but are essential and problems. a micrometer adjustment on the spe- one for the two audio tubes and one (E) A good grade variable grid cial coupler is a great help. Any of for P. & P. will work wonders and leak should be used and is very essen- the micrometer adjusted dials on the save money for the builder. tial to tone. market will serve the purpose. 5. For selectivity cut down your (F) The following arrangement of (15) It takès patience and time aerial to about sixty feet with single parts in a 7x26 -inch cabinet has to learn the technique in tuning the wire, well insulated. proven to be the most efficient lay- Superdyne, but the results obtained 6. When you heard a noise like out so far: are surely worth the time spent. rushing wind, your 'set is in oscilla- (1) A .00055 (De Forest) con- I will be glad to answer any of the tion and then is the time to adjust denser connected at extreme left end DT's who desire any additional infor- the feed -back (rotor) and bring in of panel. mation and who are actually contem- quiet the music or speech. (2) Beneath this condenser the plating on building the set. 7. A 1 -henry choke coil (iron coil) variable grid leak is mounted on and a 1 -MFD. fixed, cut directly panel. Superdyne Supplement across the ground and aerial binding (3) Directly behind this condenser Experimental posts works wonders in cutting out place the radio frequency and detec- The following information furnished for power hum and foreign battery tor sockets on back edge of base- the convenience of DT's who are experi- noises. board. menting on my hookup of the Superdyne 8. It is not necessary to use the (4) To the right of the condenser shown in June RADIO AGE and who P. & P. at all if not desired; it only with proper clearance mount the spe- have swamped me wtih mail, having re- helps to cut down distortion and pro- cial Superdyne coupler to both base- ceived eleven hundred and eighty letters duce volume. board and panel. so far. 9. Amplex Instrument Laborato- (5) To the right of this special 1. The by -pass condensers may ries, 57 Dey Street, New York City, coupler mount the other .00055 con- be .001 or .002 as the case may re- put out a kit complete with all parts denser on panel. quire. May be done away with on with tested instruments which are (6) Mount the plate reactance transformers. wonderful and cost only $30.75, coil directly back of the second con- 2. Audio transformers need not which includes a drilled panel with denser. De Forest condensers have be as high a ratio as shown; in fact, baseboard. binding posts at rear which are long enough to mount this coil snugly. After this coil is mounted, it will be found that it all will barely fit in cabinet. (7) To the right of the plate STATIC PUNCTURING reactance coil place all the audio sockets in line to nearly end of baseboard. CONTEST (8) Install audio transformers between the line of audio transformers CAN old man static stop you or can you stop and panel. Be sure to slightly turn old man static? We offer the following one transformer or mount at right prizes to DTs for the five best records sub- angles if enough room is available. mitted during the month of August. The contest (9) At the extreme end (right) is open to any reader of RADIO AGE, and any of baseboard install the push and pull type of set. The Pickups Editor reserves the transformers running line from panel right to pick the winners. to back edge of baseboard. We will be especially interested in lists sub- (10) Install jacks. rheostats and mitted by persons making their receptions on filament switch to the right of the portable receivers. three large dials on panel. Volt- The baseball season is open -who will be the meter is desirable. ones to sock old static for a home run? Wat sa, (11) A small Bakelite sub -panel DTs? is connected by right angle brackets to to front edge of panel, far enough down, however, to allow binding PRIZES posts to pass into cabinet. The following binding posts are mounted on for August this panel in the order named : Aerial. A year's subscription to RADIO AGE for the first best list submitted showing receptions made during the month of August. Ground, B -, B+ Det., B +, A -, re- A +, C -, C +. However, better A year's subscription to RADIO AGE for the second best list submitted showing sults are obtained by having a sepa- receptions made. during the month of August. rate B battery for the push and pull so separate binding posts will For the third, fourth and fifth best lists, we will award a copy of the RADIO stage, AGE ANNUAL to the contributor of the winning list. have to be added to the sub -panel in case this is desired. If any transcontinental or transatlantic reception is accom- (12) A 1 -henry choke coil and a plished, confirmation of such reception is necessary. 1 -MFD. fixed condenser shunted across the aerial and ground leads 40 RADIO AGE for August, 1924 The Magazine of the Hour 10. Do not we taps unless absolutely necessary, as these ends afford a great loss in sensitiveness. 11. In case two wires are used in aerial, transposition should be used; 005 F/XED i. e., in the center of the wires disconnect and insert strain insu- VVM1 lators and change left wire to right ; and right to left and you will be sur- prised how this will help where you 1 are located near power lines. U0025 12. Any of the Superdyne coils advertised in RADIO AGE are tested and O. K. MARVIN C. WILLIAMS. Department of Communications, Air Service Technical School, Box 353, Rantoul, Ill.

Our hat is off to Mr. Williams. If I could, I would like to shake hands with him. If every radio man in the game were Soir as generous with information, and infor- VAR/OMETER TJ mation on a circuit that he has become ac- quainted with as he is, what a wonderful MID P`IeivRE radio world this would be! Now, if some í fellow would only give a similar report An improvised low loss tuner suggested by one of our readers. of experiments and experiences with a super -het, we would consider him a regu- RADIO AGE, slots each. The antenna connection lar radio fan at heart. Remember, all the Gentlemen: is made on the outside turn of the information you may glean from your I notice that M. R. C. of Los spider web primary. The turn near- experiments is of little use if you hoard Angeles has built one of your Baby est to the outside of the coil on the it. This game progresses only when we Heterodyne receivers without suc- secondary is connected to the grid. let know of what progress we have others cess, in Trouble- Coils M and N are wound made. Radio free -givers like Mr. Wil- scanning over the also on spider web fcrms 15 liams, Mr. Gannon, Mr. Baumgardner, shooter section of RADIO AGE. In of slots. Coil M Mr. Glass and others who have given us answering this letter of M. R. C.'s has 20 turns, and M, 60 turns. The their experience with circuits are the real you first state that WD11 or WD12 inside turns of both coils are con- fellows who further the progress of the tubes will not work efficiently. Now, nected together, and then to the art. The world loves a cheerful giver, if you will be so kind as to inform negative side of the A battery. The and although you may not be an engineer, M. R. C. that I, too, have built your outside turn of coil N runs to the when you contribute a gathering of infor- Baby Heterodyne around a WD12 negative B battery, putting the mation as did Mr. Williams and the others tube with great results and that I live phones nearer to the plate of the whose work has been offered in the Pick- in Los Angeles, at 1536 East 40th tube. The diagram shown in Figure 1 ups Pages, you spell GENEROSITY with Street, I will show him how he can illustrates what I mean. capital letters. get more volume from this hookup Now as to mounting these coils, than 50 per cent of the neutrodyne it is important that it be done cor- owners of Southern California. rectly or the selectivity of the set I have done quite a bit of experi- will be lost. Drill holes in the center menting on this set and I have it so of each form. Place a 1/ -inch brass that I now can take in Oakland every screw through the form P and a nut night they are on the air. I have is run on it. Coil S is then mounted heard KGW at Portland, Ore.; I get on the other end of the screw, taking KPO repeatedly and I can tune out care that both coils are placed with local with a variation of two degrees the winding running in the same on my tuning condenser. I hear direction -preferably to the right. VAP. Oakland as loud as local. This is The two coils constitute the tener, done in Southern California, Los and are mounted on the end' of the Angeles, the worst place in the United board, in a horizontal position. It is States for getting distance on any set. advisable to use a Bakelite mount- And during Summer, too. ing board to fasten the apparatus. Let me say that the Baby Hetero- Coils M and N are mounted in the dyne hookup is the best little single same manner, but when placed on the tube hookup going. board I set them to turn in the oppo- For those who want to get results site direction (say to the left), and from this hookup, using WD12 or are mounted on the extreme end WD11 tubes, I am writing these few from the coupler. Inductance L is hints. 52 turns, which I found tunes well The antenna should be only one with the WD12 tube and 23 -plate wire, not over 50 feet long. And the condenser. A diagram showing the connections of antenna coils should only be 15 Incidentally, the outside turns of the crystal receiver which has done excep- turns; no more, no less. The tuning all the honeycomb or spider web tionally good work for one of our Dial coil should be 60 turns, which if used coils should be connected to the radio Twisters. The coil is a 40 turn inductance with a good 23 -plate condenser will frequency paths; in other words, the while in- wound on a 3/ inch tube tapped every tune very sharply. Both these coils, plate and grid circuits, the fifth turn. It is wound with No. 20 DSC which are primary and secondary, are side terminals should go to the low wire. wound on spider web forms of 15 (Continued on page 42) _ / I

AIARK Radio Companion A six -tube set completely self- contained! No need to open case to operate No exterior loop or antenna required

tL`rYy ._'..':.. v ia5;1%.,.', 1t m.v.. Zenith %VMacNMiiian's Choice

The height of Luxury Encased in a Light Traveling Bag! .. -motoring to muslo{ Here's a six-tube radio set that's entirely panionshlp it could give you on your self- contained- tubes, "A" batteries, motor parties -at the bathing beach. Pic- Listening, with the keen- "B" batteries, loud speaker and loop ture the enjoyment it could bring your est pleasure, to music and voices in the cities they antenna complete, and it's a Zenith! guests at the house-party or the week- left behind! have Packed into a small,beautifully finished end gathering. traveling case -much smaller than the Again, think how such a set would average suitcase -this new Zenith is the while away a lonesome evening in that most compact set ever made giving dreary out-of -town hotel -what a god- clarity, quality, volume and distance. send it would be to that invalid mother Do you see two little buttons -to that dear relative or friend who must those weeks and in close to the handle? Those are the spend months the hospital! controls. In order to operate the new Bilt if you have already been initiated When three is company i Zenith Radio Companion you simply turn into the wonders of the Zenith, you don't at the bathing beach. to bring in the station you need be told the extraordinary use you the controls could get from this new model or the fun it could want -then for maximum volume you give you. that the loop is facing swing the case so Just the knowledge that you could pick up this i+ that particular station. You will be aston- beautifully finished case -even as you would pick ished at the clearness with which the up your hand bag -and take it with you across and the voices come city, country, lakes, mountains, and still turn those music through -and two controls and be able to listen at a moment's in what volume! notice to the. world you have left behind -that Think what it would mean to you to thought alone should be enough to suggest the Lively orchestras enter- infinite delights provided by this new Zenith Radio tain these boys, miles and be able to take one of these new Zeniths miles from civilisation. Companion with you on your travels and outings. You will want to know more of this remarkable A real radio set -the exclusive choice of set -so light and compact, so'easy to operate, so Donald B. MacMillan for his Arctic ex- wonderfully convenient. You will want to see it for yourself, at the very earliest moment. A constant source of pedition -yet so compact that it takes up No ear- entertainment and phones, you understand. No outside antenna. Yet delight to the invalid. no more space than a light traveling bag! clarity, volume, quality, dis- Think of the fun you could have with tance! A real Zenith, packed this set -the dance music you could listen into a traveling easel Your name and address ZENITH RADIO CORPORATION, to on moonlit nights -the orchestras that on the coupon, and the cou- Dept,4 -F 328 S. Michigan Ave., Chicago, Ill. would play for you as you and your pals pon placed in the mail, will Gentlemen. gathered round the camp fire -the corn- bring you full particulars. Please sena me illustrated literature on Zenith Radio, including full particulars of the new Zenith Radio Companion.

Zenith Radio Corporation Name Receiving he atest market repor s, he latest McCormick Building Address - news deve apments, with the aid of the Zenith Radio Companion. Chicago, Illinois .. . .., ...... Always Mention RADIO AGE When Writing to Advertisers 41 42 RADIO AGE for August, 1924 The Magazine of the Hour grid leak resistance without making esting: Pickups it scratchy, the louder the signal RADIO AGE, will be. Gentlemen: By Our Readers I hope that this will be of interest In your excellent magazine for (Continued from page 40) to some of your Baby Heterodyne May there appeared an article on fans. Very truly yours, "Aperiodic Antenna Coupling." I voltage or battery connections com- A. F. VAN LEUVEN. have been using an aperiodic coupler mon to the ground. 1536 East Fortieth Street, with which I have had good success, I use a Bradleyleak, connecting it Los Angeles, Cal. so am passing it on for the boys to to the grid of the tube and the posi- fool with. As seen in the drawing, tive filament as shown. The Brad - Mr. Van Leuven wants to know if he it is an exact duplicate of the low leystat is connected in the negative can't make his Baby Het into a Super by Loss Tuner which has appeared of lead of the filament instead of the adding another detector tube and an oscil- late. It is very selective and has the positive as was originally specified. lator. We'll almost bet you could do it advantage of only two controls. Dials of the friction or gear type and still make it work, but the only The primary consists of fifteen were used and not separate plate type trouble is that when you do that, you've turns of No. 18 D. C. C. wound on condensers. This is very necessary got to have an intermediate amplifier, and wooden pegs directly on the side of for sharp tuning. A .002 fixed mica then your set runs into tubes -and $$$$$. the variometer, which should be of condenser across the phones helps to However, information of that nature is the wooden variety, having fifty clear up noises, and makes the regen- in the RADIO AGE ANNUAL, under turns on both stator and rotor. For erative action more stable. the heading of the "Junior Heterodyne." the secondary I used the stator and A mounting board of Bakelite is You might look it up. the rotor is used for the tickler. A used, raised sufficiently on the back .0005 fixed condenser in the antenna of the main panel to permit the coils Now here's something that looks inter- lead makes the tuner more selective. to be placed underneath and the tube The drawing (Figure 2), I think, sockets and controls to be placed on is self -explanatory. For those who top. On my set I put the condensers want a set that will "do its stuff" on each end, and the grid leak be- Have You Placed Your and is portable, lash this up. tween them. Entry in the Popu- Yours truly, I soldered all connections, using larity Contest? E. M. ABBOTT. bus bar wire, lugs and spaghetti. I R. No. 1, Box 152, wiped every joint of soldering paste As announced in a page adver- Petaluma, Calif. and used the paste only very spar- tisement in this and in the July ingly. issue, RADIO AGE is conducting a Now look what we dug out of the mail Before placing the set in the cabi- RADIO FAVORITE POPULAR- hag for the crystal fans: net, be sure that all ITY CONTEST to determine the soldered joints most popular personage in the RADIO AGE, are clean of foreign matter. Dust radio world. Gentlemen: off everything carefully, and clean Enclosed you will find a list of the This contest is open to all readers plates of the condensers with a of RADIO AGE, and each coupon stations received during the month of bent pipe cleaner or a vacuum clipped from this magazine is good June. This is a crystal set of my cleaner. for one vote. First tabulation of own make, and with which I have I find that a tapped 22'/2 -volt B results will appear in the September had exceptional results with in freak battery is a necessity to get á clear, issue. receptions. audible signal. I found that around If you have not already voted If I had a camera, I'd like to drop 16/ volts the WD 12 tube re- for your favorite announcer, enter- you a few photos of the set, of which sponded best. Also set the grid leak tainer, or other radio figure, clip I am quite proud. The diagram of by turning the knob all out and turn- the coupon in this issue and get friends the circuit is enclosed. I hope that ing it in until good clear signal is your to do the same. it will be of some use to those bugs heard. The higher you make the who can't afford a tube receiver. (Diagram is shown in Figure 3.) I have a card and letter of confirmation from most of these stations while others just sent a pamphlet and a card confirming the receptions. Why Pay More? This ought to win a prize on the DT list. Very truly yours, T -100 Battery Charger JAMES A. BENNETT. The Best and Lowest Priced Chester, Pa. Calls Heard by James A. Bennett, 2733 W. Third Street, Chester, Pa. on the Market \VGY, \VEAF. \VBAP, WBZ. \VMAQQ, \VHAV, \Vi!AZ, \V \\'i. KDKA. P\V;t, 9XAE, 2X1. 2XAP. 2CDC. WOO, WMP, \VFI, \VDAR, \\'WAD, WCAU, WIAD. This battery charger operates on 110 volt, 60 cycle, A. C. circuit, charging a 6 volt battery at a 2 ampere rate. Standard This seems to be another little "Long 2 ampere charging tube is used. The T- 100 is the lowest priced first -class charger Distance Crystal set." Mr. Bennett has on the market. Large numbers now in use the dope, all right -you've got to know have proved entirely satisfactory. No vi- brating parts to get out of order. Absolutely HOW to make 'em to do a thousand miles noiseless in operation. Furnished with plug or more. Good stuff! and cord for lamp socket. Battery leads marked. Fuse protects charger from acci- dental short circuit of 110 volt leads. Fully RADIO AGE. guaranteed. Gentlemen: Price complete, with 2 ampere In your issue for June, 1924, I see tube, $12.00 a radio fan from Halifax, N. S., sent in his list of stations heard. I refer to H. K. Hatheway, as l reside just ` ;, , . ,--.,-- Radio Division across the harbor from him, and am LÁCs TELEPHONE MAINTENANCE CO. naturally interested in any news from Ouality Radio Exclusively 20 So. Wells St., Dept. C, Chicago, Ill. Halifax pertaining to radio. (Continued on page 52) Get a Job Like These

Old to10,000alear Ean?350020 Years Makes Almost- $500 a Month Harold Hastings of Somers. Mass., says: hi the BIPayPIe14oI "The profit on my electrical business amounts to $475.00 a month. My success is due entirely to your instruction. You make men just ELECTRICITY your what you say- Electrical more. Blame Experts. No man will It's your own fault if you don't earn yourself if you ever make a mistake stick to your small pay job when I have made it so easy for you to enrolling for your course." earn $3500 to $10,000 a year as an electrical expert. Electrical Experts are badly needed. Thousands of men must be trained at once. One billion dollars a year is Dickerson Gets being spent for electrical expansion and everything is ready but the men. Will you $7500 a Year answer the call of this big pay field? Will you get ready now for the big job I will "I earned $30 a help you money waiting for week when I started get? The biggest of your life is you. with you-S50 a week when half through your course. Now I clean up at the rate I Will Train You at Home of $7500 a year. Thank you a thousand times for what I will train you just like I trained the six men whose pictures you see here. Just you did for me. Elec- like I have trained thousands of other men -ordinary, everyday sort of fellows -pulling them out of tricity pays big on the the depths of starvation wages into jobs that pay $12.00 to $30.00 a day. Electricity offers you more farm." Herbert M. opportunities-bigger opportunities-than any other line and with my easily learned, spare time course, Dickerson, Warren - I can fit you for one of the biggest jobs in a few short months' time. town, Va. 520.00 a Day for Schreck Quick and Easy to Learn "Use my name as a reference and depend on me as a booster. Don't let any doubt about your being able to dc what these other men have The done rob you of your just success. Pence and Morgan and these other fellows didn't have a thing on biggest thing I you when they started. You can easily duplicate their success. Age, lack of experience or lack of ever did was answer education makes no difference. Start just as you are and I will guarantee the result with a signed your advertisement. money back guarantee bond. If you are not 100% satisfied with my course it won't cost you a cent. 1 am averaging better than $500 a month from my own business now. I used to make $18.00 a week." A. Free-Electrical Working Outfit and Tools Schreck, Phoenix, Anz. In addition to giving my students free employment service and free consultation service, I give them also a complete working outfit. This includes tools, measuring instruments, material and a real electric motor -the finest beginners' outfit ever gotten together. You do practical work right from the start. After the first few lessons it enables you to make extra money every week doing Pence Earns odd electrical jobs in your spare time. Some students make as high as $25 to $35 a week in spare time $9000 a Year work while learning. This outfit is all FREE. W. E. Pence, Che- halis, Wash., says: "Your course put me where I am today, Mr. Cooke -making $750 Mail Coupon for FREE BOOK - a month doing automobile electrical work The Vital Facts of the Electrical Industry -think of it-$9000 a year. Besides that The ccupon below will bring you my big free electrical book-over 100 interest- I am my own boss. ing pictures. The real dope about your opportunities in electricity- positive proof that you, too, can My wife joins me in earn $3500 to $10,000 a year. Send for it now. Along with the book I will send you a sample lesson, thanking you for what a credit check allowing you a $45.S0 reduction, my guarantee bond and particulars of the most wonderful you did for us." pay -raising course in the world. Send the coupon now -this very second may be the turning point in your life. Send it while the desire for a better job and more money is upon you, to

$30 to $50 a Day for J. R. Morgan L. L. COOKE, Chief Engineer "When 1 started on your course I was a carpenter's helper, earning around $5.00 Chicago Engineering Works a day. Now I make from $30 to $50 a day ADBT. 2150 Lawrence Ave., Chicago and am busy all the time. Use this letter if you want to-I stand behind it." J. R. Morgan, Delaware, Ohio. 01." . ,oea `. Spare Time Work e°'{ C °, Pays Stewart 4 ys4o $100 a Month .wt`o¿,OVbec "Your course has ,i e4 y..a{ò`ev.00.CP already obtained a `cJS+ c4 to40 9 substantial increase G P in pay for me and °op yN o made it possible for ¡See" ` .4,a p5ar0 ° me to make at least Q°qcPettO $100 a month in spare GDo ótiyoec time work. You can a, shout this at the weak s4y fellows who haven't se made up their minds °J 49 to do something yet." ' °.Qí Earl Stewart, Corona, Q Calif. ?rr Always Mention RADIO AGE When 1Vriltnu to .Advertisers 43 44 RADIO AGE for August, 1924 The Magazine of the Hour

The New Zenith Super -Portable distant stations may be accomplished in the excellent tests of the designers. A The new Zenith Super- Portable is a full phonographic volume with the Super - year has been given to perfecting this six -tube radio set complete with tubes, Portable without any external equipment. receiver. "A" batteries, "B" batteries, loud speaker In creating the new Zenith Super -Port- Four important principles are accom- and loop antenna, entirely self- contained. able its designers had high standards to plished in receiver design in the Trirdyn: live up to. For it was a Zenith set which Tuned radio frequency amplification with It is fitted into a small traveling case - giving clarity, quality, volume and dis- Donald B. MacMillan, world- famous Arc- the first tube; Armstrong regenerative tance. tic explorer, chose exclusively for his ex- detector action with the second tube; re- In the case are included all the essen- pedition to the North Pole; it was a flex amplification by employing the first, Zenith Miss Florence Mac- tials of an efficient six -tube receiver em- with which or radio frequency tube as an audio Donald, a passenger on the trans -Atlantic amplifier and one -stage of audio frequency ploying three stages of transformer-cou - liner a new long - pled radio frequency, a detector, and two Berengaria, established with the third tube. These factors com- distance record over land and water, in stages of audio frequency. The set is bined the particular arrangement of this dry-cell operated. A loop antenna is per- tuning in station WDAP, Drake Hotel, receiver, give high signal strength. on the fifth day out-a distance of 3,463 The Trirdyn will not radiate when re- miles. With these records in mind, the ceiving broadcasting stations' signals, due designers of the new Zenith Super-Port- to the fact that the antenna is very able undertook to create a set which loosely coupled to the secondary circuit would live up to the Zenith name in every and a non -oscillating radio- frequency particular, and yet would be contained in amplifier is employed before the regenera- a small traveling case. tive detector, as a barrier to prevent oscillations generated by the detector upon New Trirdyn 3 R 3 Receiver reaching the antenna. The rapidly increasing popularity of The primary or antenna circuit of this tuned radio frequency in receiving sets set is aperiodic or untuned, making it pos- is clearly indicative of its extreme sible to calibrate the secondary circuit and efficiency. The Crosley Radio Corpora- the tuned radio frequency amplifier in tion has used tuned radio frequency for terms of wave length, thereby enabling the the past two years, notwithstanding the receiver to be accurately adjusted to the great amount of publicity already given signals of any broadcasting station from a manently mounted inside the case, and to tuned radio frequency of the trans- calibration table or curve sheet. the three controls -(1) A rheostat for former type. It is gratifying to know The set is selective because it employs regulating the battery current ; (2) Tun- that so many large and influential manu- tuned radio frequency, loose -coupled ing control for selecting stations; (3) facturers are turning to tuned radio antenna and a tuned secondary. The Volume control - are mounted close to frequency amplification in the design of operation of the Trirdyn is very simple the handle in three recessed dials. the new receivers. and will give excellent results with any The Zenith Super-Portable weighs only The newest addition to the Crosley good antenna. It also operates well with twenty -four pounds and may be carried line is the Trirdyn 3 R 3, announced on a small indoor antenna. about like an ordinary small suitcase. No the third anniversary of the corporation. It requires a detector and two amplifier external aerial is required for operating The Trirdyn, having passed through a tubes pf standard type. Good results are the Zenith Super -Portable, nor is it neces- thorough test from every angle and after obtained when UV 199 tubes are em- sary to open the case. The set is oper- practical use by people in various parts ployed, but the volume will be greater ated by means of two controls, both on of the United States, was deemed ready with 6 -volt tubes. The amplifier circuit top of the case. Having tuned in the sta- to be distributed to the public. Labora- employs 90 volts of "B" battery. A "C" tion you want, volume can be further tory tests are not always as practical as battery may be employed if desired. The regulated by swinging the case so that the those given a receiver under the different Trirdyn is enclosed in a beautiful solid loop is pointed in the direction of the sta- circumstances encountered in actual opera- mahogany cabinet. tion broadcasting. A station may be tion and the reports received bore out (Continued on page 64) tuned and the Super -Portable placed in full operation while it is being carried down the street, in an automobile or otherwise transported. An extremely sensitive and distortion - less loud speaker is mounted inside the cabinet with a shielded orifice through which the spoken word or music is clearly heard. Neither head phone nor external loud speaker is therefore necessary. The same principles that have made the Zenith models 3R and 4R so highly selective - permitting the tuning out of powerful local broadcasting stations close to the receiver and at the same time tuning in The back panel view of the new Crosley Trirdyn 3R3 receiver. Note the sym- distant stations - have been utilized in metrical arrangement of the apparatus, designed to make possible short leads and the new Super -Portable. Special atten- yet preserve the front panel appearance of the set. The open work style of mount- tion has been given to low -loss design and ing, and the method used to keep the tubes away from the controls on the panel distortionless amplification. Reception of insure extreme stability. RADIO AGE for August, 1924 The Magazine of the Hour 245

RADIO FANS YOU NEED THIS! $500 WEBSTER'S New Modern VALUE DICT'IONARY 1924 Radio Edition And One Year's Subscription to RADIO AGE $ 75

1,228 Pages for Size, S's7'/2 inches. Both Only POSTPAID Bulk, 2 inches Cover to Cover. Every teacher, student, reader, writer and author will find this splendid word -book exceedingly helpful in the preparation of their work. It is a recognized, authoritative guide containing practically every word in the English language in daily use and in addition hundreds of new words brought into use by the recent World War, political up- heavals, recent investigations in arts, science, and modern industrial activities never before found in any dictionary. Bold black face type, easily readable and words clearly and concisely defined. New 1924 Special Radio Edition A special supplementary vocabulary consisting of over one thousand (1,000) radio and wireless terms are herein concisely and authentically defined. This popular edition is invaluable to " Radio Fans." Order Now! This is your opportunity to secure this handsomely bound, strictly modern and up-to -date dictionary -with a year's subscription to RADIO ACE, thefinest and most authoritative radio publication on the market. The cost of the dictionary alone is $2.50, and the subscription price of RADIO AGE is $2.50 a year, postpaid. But if you take advantage of Every Radio this offer at once and clip the coupon below, you can pur- Needs chase both of these wonderful bargains, with a total value Fan of $5.00, at our special price of This Dictionary $3.75 Postpaid these Note features - USE THIS COUPON 192a Edition. Complete Reference Li- 1,228 Pages. brary. r 12,000 Synonyms and RADIO AGE, 70,000 Vocabulary Terms. Antonyms. Clear, Distinct Type. Constitution of the 510 N. Dearborn St., Chicago, Ill. Latest Census Tables. United States. Gentlemen:-Enclosed find $3.75 in cash or equivalent, for which send nie one copy of your Webster's New Modern English Supplementary Vocabulary as Follows: Dictionary, Radio edition, postpaid, and Radio Age for one year. Radio and Wireless Famous Characters in Terms. Literature. Automobile Terms. Aviation Terms. Common Abbreviations. Name Commercial and Legal Christian Names of Men Terms. and Women. Address

City State Always Mention RADIO AGE When Writing to Advertisers 46 RADIO AGE for August, 1924 The Magazine of the Hour

Selective Tuning Possible by New Vario- Coupler NEARLY perfect zero coupling in radio - frequency amplification is claimed for a vario- coupler designed by Alfred Crossley of the Bureau of Engineering, United States Navy Department, for which invention a patent has just been issued. Selective tuning is the practical accomplishment of this new coupling device. Novices and amateurs are earnestly seek- ing in these days to attain this end, especially since local broadcasting stations are creating interference with respect to long- distance reception. The newly designed vario- coupler, according to claims, provides large electromagnetic coupling with a minimum electrostatic coupling. That is to say; in many of the radio -frequency amplifying receiving sets in use today, the passage of electrostatic energy from one circuit to another has a tendency of annulling the tuning effects and thereby making difficult fine adjustments of the circuits. This vario- coupler serves the highly desirable purpose of bucking out the electrostatic e n e r g y and employing the electromagnetic energy, which alone is useful in the reception of radio communication. Structurally, this tuning device includes a rotor and stator forming the primary and secondary windings, which connect to the coupled electric circuits. The stator takes the form of a tube or cylinder and its windings are in the interest of the least dielectric loss. The rotor, on the other hand, is in the shape of a disc mechan- Photo from Fotograms ically mounted in a plane passing through GIRLS BECOMING RADIO EXPERTS the diameter of the stator and at right Gone are the days when one had to be a man to understand the intricacies of angles to the axis thereof. The rotor, like radio apparatus. Now girls are employed extensively in the big radio manufac- the wheel of a wagon, contains a hub with turing plants to make and assemble radio sets. Two interested girl workers are spokes. shown above assembling vernier wheels on clarifier panels in the Grebe Mfg. Plant, The windings of wires on this rotor, or Richmond Hill, L. I. Their positions were won only after long study of the revolving portion of the vario- coupler, principles and practice of Radio. resemble a spider web, the turns of wire being threaded upon the spokes and spirally built up to occupy the length of the latter. In practice. when this vario- coupler is sets when operating over a band of wave used in the tuning circuit before a radio - lengths of narrow margins. And with ap- frequency vacuum -tube amplifier, the proximately 500 broadcasting stations in stator or primary winding is connected in operation, this condition exists at all the antenna ground system while the rotor times. This is accomplished, in part, by or secondary winding is identified with the the elimination of electrostatic energy input circuit of the first stage of the radio - and the maximum building up of the elec- frequency -tube amplification. vacuum tro- magnetic field. The degree of electromagnetic greatest by the Patent coupling is accomplished when the flat The papers granted area of the rotor is in a position parallel Office accede to these claims : A vario- with the'direction of the turn of the wind- coupler having a large electromagnetic ings of wire upon the stator; whereas, coupling with minim um electrostatic zero coupling takes place when the flat coupling; an instrument attaining a more area of the rotor is approximately at right perfect zero coupling than found in any angles with the direction of the turns of vario- coupler yet introduced; and a de- wire upon the stator. vice which may be connected in a circuit The Crossley vario- coupler should be and arranged to secure extremely selective useful in exact tuning of radio -receiving tuning of the circuit,.. RADIO AGE for August, 1924 The Magazine of the Hour 47

At your lap. Al your dealer's dealer's s or postpaid by

or $4.75 1. post- TRY THE paid. NEW

Planstiehl Shock -Proof Sockets for 199 Tubes. Compact, efficient sockets for portable sets, the last word in careful desi gn. 50 With two -turn coils, variometer ordering, specify P. for panel PERFECT OF PURE In with RATIO IN- or b. for base mounting. DUCTANCE. P -101 (h. or p. ), Single $0.70 P -300. Pfanstiehl Variometer $5.00 P -102 (b. or p.). Two- Gang 1.00 P -600. Pfanstiehl Superheterodyne INDUCTANCES P -103 (b. or p.), Three -Gang.! 1.50 Oscillator 6.00 Other Pfanstiehl Pure Inductances List Wave Turns Price Length FOR RADIO EFFICIENCY P -201 25 $0.55 100 -340 P-202 35 .59 125 -470 P-203 50 .65 170 -650 P -204 75 ,74 220.960 You have been trying out all kinds of circuits. P-205 100 » P -206 150 1.10 470 -1980 ( like best. Let us suggest Pfanstiehl Ultra Andiron $0.95 You know those you Pfanstiehl Reinartz 175 that you now endeavor to improve these favorite circuits to atheir highest efficiency. Much has been said recently about the necessity of good parts. Inductances are of extreme importance for efficiency. Pfanstiehl Pure Inductances are good because: 1. Air -cored means no absorption of signal strength ; 2. Stagger -wound means no appreciable distributed capacity; 3. Vernier control of adjustment means distance- getting. Manufactured by Pfanstiehl Radio Co. Highland Park, Ill. IP -500. A new wave-trapefficiency secured with I Chicago Office: 1001 W. Washington Blvd. (Haymarket 8010) special double Pfanstiehl inductance $i.00

Buy a Hecrciset= 4$ you'll be proud o c r -.'.v, WEIGHS RA®II® ONLY 80Z To,

¡PlAOSlag-c CS I afetoc WORLD'S OURS 00,000.00 COMPANY GREATEST HEADSET STANDS SQUARELY BACK OF EVERY HEADSET VALUE Longer Cord (full 5 feet), Stronger Magnets, Higher Resistance, Increase of Sensitivity, Perfect Tone Mates EVERY SET TESTED BY LICENSED RADIO OPERATORS Send no money- Order on a Post-Card THE TOWER MFG. CO. : 98T BROOKLINE AVENUE, BOSTON, MASS. scieniific r, i._ ', À'4 ,Always Mention R 1 .1(.IS When Writing to Advertisers' -ti RADIO AGE for Au;ust, 1924 The Magazine of the Hour Takes the "Great Things Are Coming photographs by wireless. They will then for Radio On the Farm" work on the more difficult problems of reproducing at a distance moving pictures MYSTERY (Continued from page 35) of moving bodies. You will sit before your radio set out Western ranch. ! In the old days they there on the farm and hear the Presiden- out of RADIO could cuss the cook and play cards. Now tial address while you watch his gestures Just one book answers every ques- they can carry a radio outfit on the wagon, and the crowds about him. Opera and and pluck out of the night voices of many drama in a distant city you will both see tion about this modern miracle distant cities, while in a mean room in and hear. You may have almost ringside some city slum the owner of a fifteen - seats at the world championship match, dollar set may hear John McCormack, and thrill to the swat of the "Babe" Ruth Mary 50,000 SOLD Garden, Chaliapin. Neither the of that day -all in your own sitting -room. cowboys on the plains nor the victim This will never PAGES of be a complete substitute 514 city poverty need any longer be isolated. for seeing and hearing the opera and the It seems probable, judging by experi- play or the great political or sporting Compiled by ments already made, that, in the course event-but then indeed will the farm cease HARRY F. DART, E.E. of four or five years of research, engineers to be "isolated." Formerly with the Nvill have perfected methods of rapid, Western Electric Co., and U. S. accurate, and detailed transmission of *Courtesy Farm and Fireside. Army Instructor of Radio.

Technically Edited by F. H. Doane Simply a BE A RADIO expert -it's easy for the 13 50,000 who own this compact, complete Radio Handbook. Written in good, plain, Matter of understandable language. Crammed full of facts, every one useful and important. Explains how receivers and transmitters work, how to build and operate them. Whatever you or your friends want to Taste know, it's here. Will save you many times its small cost. Some persons are satisfied if their TELLS ALL ABOUT: Electrical terms Loud Speaker will produce big volume. and circuits, antennas, batteries, genera- The more discriminating, however, tors and motors, electron (vacuum) tubes, every receiving hook -up, radio and want their radio reception to corne audio frequency amplification, broadcast from the Loud Speaker with all the and commercial transmitters and receivers, super- regeneration, codes, license refinements of the original broad- rules. Many other features. casting. Nothing else like it. Make this extraordinary book your radio library - It is for these more refined in taste that just this one little giant is all you need. Everything in one index, under one cover, Bristol Audiophone is particularly in one book, for one dollar. The biggest suited. Here quality has not been sac- dollar's worth in radio to -day. Combines the knowledge of many expensive works. rificed to obtain volume, but the two Buy this and save the difference. Stop have been combined in pleasing pro- experimenting in the dark. Before you Bristol spend another cent on parts or even Audiophone portions. touch a dial, sign and mail the coupon Loud Speaker below and get this unique guide to suc- The Audiophone is ready to use -no cessful radio. auxiliary batteries required to operate. Send $1 to -day and get this 514 -page 1. C. S. There are three models to select from, Radio Handbook -the biggest value in radio $30.00, Junior $22.50, to -day. Money back if not satisfied. including Senior and Baby $12.50. TEAR OUT HERE ------] INTERNATIONAL CORRESPONDENCE SCHOOLS Box 8782 -B, Scranton, I'enna. If sufficient amplification is not avail- I enclose One Dollar. Please send me -poet- able in your set to operate a Loud paid -the 514 -nage I. C. S. Radio Handbook. It Is understood that If I am not entirely Speaker, a convenient unit is provided satisfied I may return this book within five Jays and you will refund my money. in the Bristol One Stage Power Am- plifier. When used with Loud Speak- N mie ers of the better class and particularly Address ...... with Bristol Audiophone, music and ------J speech are reproduced without any distortion that the ear can detect. Any desired amplification can be had by 5000 connecting several Bristol One Stage RADIO DEALERS together. buy from Power .Amplifiers HUDSON -ROSS Price $25.00 123 W. Madison St. Chicago Ask for Bulletins Nos. 3011 and 3017 -P Send for dealers discount. Bristol Made and Sold by One Stage Power Amplifier The Bristol Company I MAKE THE BEST CHOCOLATE BARS Mints and Chewing Gum. Be my agent. Everybody Waterbury, Connecticut will buy from you 1Vrite today. Free Samples. MILTON CORDON, 106 Jackson St., Cincinnati, Ohio RADIO AGE for August, 1924 Tite Magazine of the hour 49 A New Service to Aid the Radio Public In Buying Efficient Sets and Parts By EDMUND H. EITEL Vice-President, Pfanstieht Radio Co.

SERVICE? What is it? Perhaps we tomer gets into difficulties. And so, the had better ask, "What isn't it ?" If Too Many Radio Fans manufacturers' knowledge is widened into the vacuum tube is the "heart of the a new field of troubles, due for the most receiving set," service is the heart of the Are Duped By Failing part to the customer's unfamiliarity with radio industry. A receiver is not a few the technical side of the apparatus. This pounds of wood, metal, and rubber, which to Do Buying Wisely; results ultimately in simplification of are worth intrinsically very little, but it design. is the most marvelous service that science Radio Age to Tell How RADIO AGE has asked me to set down civilization, a sery has yet contributed to points of practical, as contrasted with ice which annihilates space and time and . theoretical, experience on data sheets in the ordinary considerations of economics. selling radio. These discussions will not the form of buyer's guide or service. And so, from the manufacturer to the deal with the theoretical requirements of During the coming radio season, we shall public, we deal not so much in radio mate- voltage, capacity, etc., which are covered hear less called hookups and rials as in radio service. It is just as in the usual diagrams and articles. but of so- "new" important for the public to recognize this, with a side of the subject which has been more about improving the efficiency of as for the man who wholesales or retails neglected; namely, the practical points those circuits which have demonstrated radio, in order that the merchandising of one needs in selecting apparatus. What their superiority. For this development radio may be placed on a more depend- you want to know chiefly is how to buy of interest such data will be timely. able basis and those merchants eliminated apparatus which will work and work most Since the data on these sheets will aid who sell apparatus which will not work efficiently. those who buy as well as to those readers properly. The group with whom I am identified who sell radio, they will be called a Let us illustrate with what service is received some curious advice when it "Buyers' and Sellers' Service." They will not. A certain manufacturer, who is noted proposed to make sets. We were warned supplement and be convenient to bind for doing his utmost to make products by a manufacturer of parts to leave sets with Mr. Rathbun's technical data sheets. of the best design and workmanship, re- alone. The trouble with making sets, he cently discussed his line with a small New said, lay in there being so much junk in The First of the Buyers' and Sellers' York dealer who said, "I believe your radio apparatus that you had the greatest Service Sheets Will Be Found goods are the best and I know how well difficulty in building a set which would on Page 50. they are made. That's just why I don't work. If you sold parts, he said, you carry them. You see, when I sell the were relieved of the responsibility of Sonora Phonograph Co. Produces junk I now carry, the customer usually making the set perform. Radio Speaker brines his set in and gives me a chance to In the course of many experiences we The Sonora Phonograph has make a profit repairing it." have often laughed over this advice. After Company That dealer will not be permanently in the manufacturer designs his apparatus, recently produced a Radio Speaker which the radio industry. Fortunately, there are he reviews the materials and parts avail- is a radical departure from the established few merchants who talk in this way. and able, tests them, and makes his selections. type of upright horn loud speaker, and who know and care so little about service. Next he buys a very great number of the which bears evidence of becoming exceed- To eliminate such menaces to the health units selected and learns how many hun- ingly popular with radio enthusiasts. of radio, we need more intelligent buying dred different ways they can fail to work. The Sonora Radio Speaker differs from on the part of the public, and this leads Occasionally, despite all the manufactur- those now on the market in two major us to the question of where service begins. ers' foresight and final testing, the cus- characteristics; its horn is concealed in a There is apt to be a vicious circle mahogany cabinet, following present day started when dealers sell without con- practice, and it embodies the most ad- science, and the public will buy anything. vanced theories of tone production as Weak manufacturers will be tempted to HOW DID THEY GET developed by this successful phonograph furnish junk and the newspapers to print company's engineers. hookups to serve. The public, while THAT WAY? Incorporated in this Radio Speaker is uneducated, is duped. What did the radio announcers the famous Sonora We have had some experiences of this tone passage, consist- and entertainers do before they ing of a highly developed, correctly pro- kind in the first few years of radio and were brought into the limelight by we see now that to begin with the public the sudden advent of radio popu- portioned all -brass tone arm and the must be well trained in the fundamental larity? Sonora all -wood, laminated horn. It is principles of radio by the radio journals. Some were unknown completely. the product of years of thought and ex- The manufacturer must build with fore - Others were struggling along at periment pursued in the interest of high sightfor the future; must not "fall" for some kindred occupation, such as quality sound reproduction. When it is the temptation to sell even fads. The theatricals or public speaking. realized that the principle of sound re- first Overnight they became familiar - production wholesalers must think of all not by voice and name, though not by applied to the phonograph what will sell today, but what reputation sight-to millions of radio listeners. holds true in radio, then the significance is he building? And the dealer the same. The story of how many studio of this latest addition to radio reproduc- The dealer, like the journal, can render an favorites rose to fame and how they tion will be appreciated. invaluable service by helping educate the did it ought to prove of interest to One of its chief bids for popularity is public in the fundamental principles of every RADIO AGE reader. The its small size. It measures only 16/ good buying; and grateful customers will first of an interesting series on this inches long, 9/ inches high and Q'/ pay him in the long run. subject begins in this issue and inches deep. Combined in this small space No other industry has ever before will be continued in the September is the large, full tone passage, represent- placed such a difficult technical problem RADIO AGE. Order your copy ing skillful engineering design. It is in the hands of the public. RADIO AGE from your news- dealer in advance equipped with a length cord to insure getting this All -Star generous of offers a solution of this problem in a number. and connections for use with any good series of Service articles on buying and receiving set. RADIO AGE for August, 1924 The Magazine of the hour '

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w ñ ?,° C n r 3 - x C) to ÿ C E G q Ó. Ó 'D' G g ''' WS =m 7 0 m ° F O r.;R 0.: Äó 3 RADIO AGE for August, 1924 The Magazine of the Hour 51 American Boy Important Factor in Summertime Radio The American boy, with his wonderful adaptation to electrical and mechanical development, continues to be a factor both in the progress of the radio art and in the Summertime demand for radio apparatus, according to reports received by the Radio Section of the Associated Manufacturers of Electrical Supplies. He is supplementing his Winter book - studies with practical work at home, in camp or at the seashore. Pierre Bouche- ron. chairman of a committee now com- piling statistics on the subject, declares the outstanding fact already developed is that no other scientific achievement in recent history has so captured the imagination of "millions of American boys as radio has done. "In this case, at least," Mr. Boucheron adds, "it stands thoroughly proved that the American boy is father to the radio man." Radio has created a new type of elec- Baldwin and Bakelite trical experimenter with the result, as Mr. Boucheron points out, that many of The clear tone of this popular under varying atmospheric con- the noteworthy developments in the art headset, made by Nathaniel ditions, Bakelite shows no signs have been brought about by comparatively Baldwin, Inc., of Salt Lake City, of deterioration. Its color does young men. has been developed by careful not fade and its fine finish is "Boys of today are astonishing their experimentation in every phase impervious to oils, acids and elders with glib references to such recon- of its manufacture, from the moisture. dite subjects as electrons, ether waves selection of raw materials to the and radio frequency amplification," Mr. final testing of the completed in- "The Material of a Thousand Boucheron continues. "These boys under- strument. Uses" possesses many valuable stand the fundamentals of electrical properties which make it pecu- theory and practice and the complex Bakelite is liarly suitable for use in radio changes undergone by electrical impulses used for the receivers equipment. in a radio circuit. because it is strong, and light "Radio this Summer has taken the in weight. After years of service Send for a copy of Booklet H. American boy off the street corner and placed him in his home -made laboratory. Instead of lurid novels, he now reads the B Send for our Radio Map authoritative radio magazines. 00 "Radio is teaching the boy a greater The Bakelite Radio Map lists the call appreciation of music than he could pos- BAKELITE letters, wave length and location of every sibly have attained from painful `music Condensite broadcasting station in the world. Enclose lessons' or lectures on the subject. It has 10 cents to cover the cost and we will send i 'Dr1ANOL you this map. Address Map Department. given him a more graphic knowledge of are the registered current events. Radio Sunday sermons Trade Marks for the Phenol Resin Products bring the teachings of religion home to manufactured under BAKELITE CORPORATION him. patents owned by BAKELITE 247 Park Avenue, New York, N. Y. "But the gain is not all one -sided. The CORPORATION Chicago Office: 636 West 22d Street youth of the nation perhaps have done as much for radio as the art has done for them. For the fact remains that it was the boy who first `sold' the idea of radio to the entire family. It is the boy who THE MATERIAL OF A THOUSAND USES keeps the older folks informed of developments in the radio art; it is the boy You Can Also who determines very largely the type and Charge HOWARD PARTS character of radio equipment which the No. 1001 Rheostat, $1.10 family shall buy; it is boy who No. 1003 Potentiometer, $1.50 and the "B" Batteries No. IOC2 Micrometer, $1.50 this Summer is making radio a year -round At All Dealers. necessity rather than a seasonal luxury." wnf at Home ! The AI'CO "n" Battery Charger is a worthy ally to the successful AI'CO Charger for A" batter. íes. Renews any 24 or 48 volt wet "II" battery in ten hours - "THE TROUBLESHOOTER" without disconnecting set. It's noiseless. clean and as easy to hook up as an electric iron. Due to unexpected changes in Complete with wires ready to use. X10. Write for interesting (1' makeup of this issue of RADIO circular and nearest dealer's naine. APCO MFC. CO., Flak St. Dept. A AGE, the "Troubleshooter Sec- Providence R. I. .,,; i tion" for fans is omitted. Watch 4248 N. Western Ave. September RADIO AGE for an ...:ri, 1!1111'filhl i : extraordinarily big section an- The Second of RADIO AGE'S Articles swering all the latest technical on Tube Efficiency Will queries. Appear Next Month 52 RADIO AGE for August, 1924 The Magazine of the Hour Pickups 9 Jiffy By Our Readers RIBBON (Continued from page 42) ANTENNA Instead of the honeycomb set used by him. I am using the old - Low Resistance - fashioned, much -abused single circuit, Big Reception! and although I must have caused interference at first, now I can con- Strengthen the incoming signals -get the weak ones -"Jiffy" sistently tune in stations by setting $GOóo does that. Easy to install -set the dials. The tickler coil is set at it up in a few minutes. It is zero first, then the condenser is set TUNED weatherproof-cannot rust or for the proper wave length, then I 5-TUBE corrode- exceptional high ten- sile strength. reset the tickler dial, and no squeals are heard either in my phones or in RADIO FREQUENCY Supplied complete with two insulators -ready the neighbor's. It is just as easy to to install. At do it right as wrong if one keeps a your dealer's or log. FitEsHmAN direct, One Below are the stations I have con- Hundred Feet- sistently heard up until the end of April, when I ceased listening in. MASTEIREcE All these on two small peanut tubes: At your dealers; otherwise send pur- $I.50 chase price and you will bo supplied without further charge. \ \'CAR (once an entire program), KFKX, Apex Stamping Company WRAN, \VCAL, \ 'SB. \\ DAP, \VL \V, DeDt.X. \VNAP, \V1VI, \VCAD, \\'RC, \VSAX, Riverdale. Ill. KDKA, \VGR, WMAK, \VCAP, \VHAM, Chas. Freshman Co. Inc. \VFI, \VIP, WOO, \VDAR, \VOAX, \VOR, ©r prtrd gtadio Produis, \VGY, \VBZ, \VEAF, \VIIN, WJZ, 106 SEVENTH AVE. NEW YORK, \\'MAF, \VHAZ, \VJAR, \VNAC, \VGT, CHCX, CHYC, CHXC. I want to thank both yourself and - Mr. Kennedy for the suggestion of IIRADIO grid leaks across the secondary of the transformers, as I am sometimes PAYS DIG bothered with shrillness of tone. EARN 53000 to59000aYear Thanking you again for many val- Radio Age Enter fast growing radio field, thousands of big pay uable hints I have received in your jobs waiting for you. U. S. Gov't., Steamships, R. wonderful magazine, I am, Announces R's., Corporations eagerly seek Radio trained men. Advancement rapid, earn from $3000 to $9000 yearly. Yours very truly. J. T. CREELMAN. Prepare for Big 198 Windmill Road, An Unusual Pay in SpareTime Dartmouth, N. S.. Canada. My reputation as Radio Engineer and instructor insures you complete, speedy success, at home in RADIO AGE, Technical sparetime; earn while you learn. Gentlemen: I make you expert in radio design- ing, building, repairing and operat- I am fifteen years old and I believe ing and teach you only practical that I ought to be admitted to your for A. C. MOHAUPT Service "inside" dope. You quickly complete my course and step out into Big Pay. No ex- Loyal Order of Dial Twisters. I am perience required. a regular reader of your magazine and I like your technical articles. As Radio Fans FR EE OUTFIT to my opinion of your little maga- 1000 MILE TUBE SET zine I think it the best of its kind. For a short time I will give tube radio set in handsome cabinet to men who I am enclosing my list of stations Illustrated ersoll now, absolutely FREE. Send January. at once for my FREE wonder -book of heard since about inside Radio "dope." KFI, KM. KGO. KPO. KLZ. KFAF, A. G. MOHAUPT, Radio Engineer, KYW, KFLZ. KFNF. KFKB. KOP, KFOY, Never before attempted RADIO ASS'rt OF AMERICA KSD. KFIX. KFKX, KG\\', KFGL. KDKA, 4513 Ravenswood Avenue, Dept. 28, CHICAGO KO\'. KFFZ KFOP. KFIZ. ('YB, CYL, Dear Sir: Send me your FREE Radio Book and your limited CHYB, CKCH. CFCA, CFCN, CKCK, by any publication. plan without cost or obligation. CKAC. N'MA \', \VSY. \VEAP, \VKAN, \\ABE, \\'CAP, \YEAS. WMU. \VRC, Name \VSB, WEBH, \VGN. \VAAF. \\'DAP, A Positive Revolution \VMAQ, \\'PAD. \\TAS, \VTAN. \VR\I, Adurese City \\ t'B ), \\'I.S. \V \CAE, \VOAG. \NOT, \\ .1.\K, \\'SAL, \Cí11, \BIAS, \\'DA- , in the Radio Publication \\OC. \\'HAA, \VHAC WHO. \\'OAK. \VHAS, \VAAB, \VKC, \VSAR, WBZ. \WAS. WCX, WWJ, WOAP, Industry! \V\VAO, \\'CAL. \\'FAN, \VRr H. \ \'LAG. \VBAH, \\'AAH, \VOS, \VDAF. \VHB, \\'CK. \\'MA \NEB. \VOO, \VOA% \', KEEP OFF THE ROOF \ \'1AW, \VAA \V, \VOR, \\'HAR. \\'GR, Complete in \ \'CAD, WMAK, WEAF. WJX, \\'JS, WIZ, WHN WSAP. \VGY, \\'H Z, Aragon's \\'l1AM, \\'AAD, \\'LW, \VSAI, \\'PAL, \VBAV. WOAC, \VABT, \VGAF, \'LAL, SEPTEMBER Silver -Indoor -Aerial \VNAD. \ \'Oa\', \WAU. \VOAR. \\'R. , Made of Phosphor Bronze and Sterling Silver. \VIP, WOO, \\'JAS. WJAI. \VPAB, Can be used in aii :Lee ro'+m. Has capac- \ \-CAM. WI AD, \\'TAR. \\'SAD. WMC, ity of ISO -foot outside aerial. Cuts down WNAV, \VFAA, W$AP. WIAC. \VEAY, RADIO AGE static -Gives sharpest tuning- Practical WFAH, \\'CAR. \NOM. \\' AD. NAA, and ornamental -For any home. Shipped \VPAH, \ \'CAY, \VIAO, \VAl K, WHAD, on the stands about August 25. all ready to be installed. @2 \VOAY, \VHA, \\'RAL, \\'LAY, \\'KAQ, Aerial complete...... p 5Ua7 P\ \'X. 6K\V. Mail your order today. r These stations were all heard more Watch For It! ARAGON RADIO CO ., cake có' than once and can all be verified. RADIO AGE for August, 1924 The Magazine of the Hour 53 I use a three -tube single circuit set. Most of the above stations come in ÁDIO-LIBRARIF.. on the loud speaker. It is not at all - uncommon to hear KGO on the loud JUST SEND A POSTCARD I GET absolutely Ires -the A -t speaker. YOIV GET "Library of Latest Radio Literature," written by loremost radio Hoping to find my name with the authorities. Contains HUNDREDS of saleable wiring diagrams. HOOK -UPS. Dial Twisters, llustratlons, articles, data, etc. . deratsnd ble I am, EXPLAINS 1::47,V , the popular now To Each oie-cuits: refier, trodync, ph uniform RALPH RIPSOM. dyne, to.. J bomeleee,lw to build este. Covers long and short wave amplification, push-pull and sud,, Purchaser 544 20th Street, ficn. Latest information Iti- Milwaukee, INCLUirifle other radio eub)eete. LOG BOOK a Wis. INCLUDED FREE. Aleo our latent Radom Catalog o% TISED attractive savings. Write today -Otter limited. Address World Battery RADIO AGE, ATWOOD -KING, Inc. Dept.P-g,t63 W. Washington St., Chicago A 24 -Volt "B" Storage Batterypositivelygiven Gentlemen: FREE with each purchase of a WORLD "A" After reading some of the rec- Storage Battery. The WORLD Battery is famous for its guaranteed quality and service. Backed ords hung up by "Dial Twisters," OD'KN6 by years of Successful Manufacture and Thousands of I ATW Satisfied Users. You save son. decided to construct a reflex set, Prices That Save and Satisfy which proved inefficient. Then I Auto Batteries Radio Batteries monkeyed on a one -tube hookup of 6 -Volt, 11 Plate $12.25 6-Volt, 80 Amps. $10.00 my own, which 6 -Volt, 6 -Volt, 100 Amps. 12 :50 has proved a "wow." 13 Plate 14.25 6 -Volt, 120 Amps. 16.00 12-Volt, 7 Plate 17.00 6 -Volt, 140 Amps. 16.00 Below are a list of stations bagged EQUITY Shipment cent dúoottnifoi eneh nfull u ithorder. by my set. 2 -Yr. Guarantee Bond in Writing KDKA, \VTAM, W\VAE, \VBZ, CJCG, THE REAL EQUITY SHOP With Each World Storage Battery \\'CAP, \VCAM, WGY, WCAE. \ %TSB, 1331 N. Wells SI. proves satisfactory World performance. Mall this d witb \VIP, WDAR, your name and address - we will ehlp battery toy order Is re- WEAF, WAID, WJZ, WJY, CHICAGO ive you your chol of B" Sr rage Battery \VMAL WGR, CKY, CFCF, \VNAC. haIved:nd omenickle aoho'', finish Auto Spotlite, FREE. Write TODAY. WJAR, \VRL, KYW, WDAF. \VOA\ WORLD BATTERY COMPANY KGO, KFI, WMAQ, \VDAP, WBA \, SPIDERWEB COILS 1219 So. Wabash Ave. Dept. 36, CHICAGO, ILL. \VSAI. WPAB, WJN, WRC, \VAIT'. This FREE "B" Storage Battery takes the place of dry cell \\-DM, B" batterie.. Can be recharged and will last indefinitely. WHAZ. W H, MAY, \\-CBD. Use low loss inductance coated tvith To be sold egad for $6.00. It 1 s the only battery of Its kind \VHN, WHAR, \VH \VOR, WL\V, NYE!, equipped with solid rubber case -and Insurance against acid Waterproof Anti- Capacity Cement. and leak'cte. Take advantego of this remarkable Introductory KSD, NAA, KQV, P\VX, \VGI, WHAM, offerHer NOW. (To those whoyr fer It, we will send FREE a KFGZ, WBAP KFKX. 6KW, Rubber Plugs for mountings. all ane nickel finish AutospoUile, Instead of the B" Bat- WOO, CFAC, tery. Be sure to epeelfy welch Is wanted.) WWJ, \VCAL, \VGL, CFCA. types wound to specifications. No \\'RAM, KFKB, WIAG, WFAA, \VCAJ, GIVEN WHAA, KFAF, WABQ, \VBBG, \VGR, order too small or too large. quantity FREE '.VGN, \\'TAR, WOC, WOS, \VAAM. production solicited. Send BLUE To introduce WCX, WBT, WRAZ, \VMAK, this WGAN. PRINTS for quotations. Try a set euperlorr Word "B' Storage of our Spiderweb Air Core Harkness Battery to the On the first night I tuned in forty - Public. Coils, list $2.00. Special prices to one stations. Altogether I have Dealers and Jobbers. tuned in eighty -four stations, the farthest being KGO, California, about 2,500 miles from here. Will be pleased to give information re- Write forr a copy garding my set. FRET. MAP Yours very truly, ey JOHN F. MULLIKIN. FREE & LIST today 128 Bates Street, N. W., N II 463 BROADCASTING STATIONS Building Washington, D. C. aRadto Set Late-A, P. S. -Do not think hearing the completest, just published. Call num- t Eisemann bers, locations and wave lengths. Sent PátlsaaPdnels coast was a freak. for the following absolutely free with our compliments to day I picked up KFI and held it for every reader of RADIO AGE who will write half an hour. us a postal c -ird or letter stating what kind of radio reception they are now most interested in-one tube, three tube or five tube. RADIO AGE, Send today and get a treat. Gentlemen : LARGEST RADIO DEALERS IN AMERICA About two weeks ago I got the bug. The Radio Shack, Dept. RA8,5S Veoey St., New York. A friend of mine let me have some F ad. magazines. Among these I found RADIO CABINETS the RADIO AGE for January. I followed instructions RADIO SETS the and built EQUIPPED PANELS A new twenty -four page booklet the Rosenbloom circuit. Last Mon- will be sent, gratis, to those in- day I was ready to try the set, and Ash Us About PHUSIFORMERS terested in building their own the first station I heard was KFI of receiving sets. Los Angeles, Calif.! LAKESIDE SUPPLY CO., Dept. R 73 West Van Buren Street A simplified method of construc- In six I have heard - days sixty Telephone, Harrison 3810 CHICAGO, ILL. tion is described. Illustrations seven stations, many of them being and diagrams. over 1,000 miles away. Saturday FERBI:NU On Request night from 7:30 to 1:00 o'clock the r71ie (7raffic CopCo EISENIANN MAGNETO CORPN. following stations were heard: oo the, air h FEB, 11.1 William N. Shaw, President Calls Heard by Jewell A. Goddard, Add a Ferbend Wave Trap I to your sot and' Poli yloeur Dept. K Farmland, Ind. reception. Regulate the Traf- .,1-'I, fiel Ounranteedto tuneoutaS? ' ! 165 BROADWAY. NEW YORK WBS, WMAQ, KYW, WRC, KSD, Intortoring elation. Sent ppoet- '' pyaid on receipt f $8.50, or C. D. WGY, KPO, KGW, KDKA, WLS, OS for freénbooklet. Lea Ferbend Electric Co. I WGN, WFAA, WOC, PWX, WDAF, 16E. South Water St., Chimera KFI, CKAC, WEAF and WOAW. They were all heard very clearly. RADIO AGE ANNOUNCES: If I had a transmitting set, I'd give B -METAL for volume three cheers for the RADIO AGE The most unusual radio innova- and for distance. Ask tion for fans ever published. Original your dealer. and add, long may it live. -helpful- authentic. In September B- METAL REFINING CO. Yours very truly, RADIO AGE -on the stands about 5th Boot, 525 Woodward Ave. JEWELL A. GODDARD. August 25. Don't miss this all -star DETROIT. MICH. issue! (Continued on page 55) 54 RADIO AGE for August, 1924 The Magazine of the Hour

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Ó. < 0 S v â á ° ñ n v v ,ne n, â e ,g t.. e) ° -ê T R ° a ó ó. o ó ánw=e O á ; ä ré c°.' ô H 3. rnóe 50 t., ó? ÿ °.a a v a ^ n 3. . w n Yf +° Ó ñ o v 7' o Á - - o !,;4.F1 o n -' yr ^d 5 FIT n3óo ppópp v ÿ Á m r 3 3 w > > v ó o- -v,-.so- ovñ ° 'n xd w c 8 5 y Ñ $ y 3 n 70 n v ro. 3 ÿ^ c m Á w n ÿ w^ O s'.1 F, 7 C C= C Vw c v r0.e o v á) v n n °. %r . _ ; Á 3 3' w ñ o ñ Ä á.ö mró á & ó n gItwó ^ n 7 9: O ^ n ^ ñ Á m. Ñ aw S - ö E 0.-w ,y n _ A w ñ m ñ á : ci S ö ,, m I X i v ñ 3 A ó n o S - Sl w ç n rn QQ3 w ñ g r. 5 a r. o : 3 aa ñ ^ w o co v cw Ç /1/ ' c ñ w á _ ra 3.jó3 -_03' y SI 2 ' 7 o s Á ó y ñ ñ w ~ 5 rp n 7 o á) - M71 O o ,. ó 3 ° C g 0 ..I. wy r _b v n - ñ A Y r C b °q w w N Ó > ,j 7 a w 5rwá 1. O tr.', c °', C o - + S Ó Ç ñ Ó C 3 7-1 Er ;: v 3 `r1 3 = ' B pÁ9 8.có,n,á i ^' w e ^3 v ÿ r; á m .7 T a-. O : .p A : 3 " n v n n n z m 00 3 Ö ó vN, ó R.- n c- 7 y`) S ö ..) F : O ^ A' C Á. -' N n x' Â= n eó ¿ T - + o -. P O 7 7 rá m : cyñ F" c7n ñ'i' ó 7 7 7 RADIO AGE for August, 1924 77íe ifa,a ine of the Hour 57 here to the extent of building one Pickups for themselves. Yours very truly, By Our Readers NORMAN E. RINGLER. (Continued from page 55) 134 King Street, Guelph, Ont., Can. static abated, and I got KGO like a To the Man with an Idea local station. Low Loss Tuners r' -that's the little set I cffer a comprehensive, expe- I am willing to pass this circuit on in the March, 1924, issue. What this rienced, efficient service for his , to any brother radio fan who desires fellow says for it is enough to make any- prompt, legal protection and the de- , velopment of his proposition.X it if he will only write for it. one throw their super- iodine receiver out Send sketch of model and descrip- There is another set here in town the window. tion, for advice as to cost, search }. ; through prior United States patents, I made and the owner thinks it great. etc. Preliminary advice gladly fur- I had a crowd May 30 and 31 up The letter you last read was the con- nished without charge. My experience and familiarity with at my house just to look over this cluding contribution to the July Pickups various arts frequently enable me to little wonder. Pages of RADIO AGE. In signing off we accurately advise clients as to probable patentability before they go to Those Dial Twister buttons are wish to say that the supply of buttons for any expense. the thing -I'm sure I would be the contributions has been entirely ex- Booklet of valuable information proud to wear one. hausted and as soon as a new supply can and form for properly disclosing your idea free on request. 1Vrile You -s for better radio, be made we will again be shooting them today. WILLIAM WEIGHTMAN. out to those fellows whose letters could P. O. Box 288, not be printed, due to lack of space. In RICHARD B. OWEN, Patent Lawyer 81 Owen Bldg., Washington, D. C. Middletown, Ind. the meantime let's all get ready for a big 2278 -M Woolworth Bldg., N. Y. City rush of things in the September issue and RADIO AGE, here's hoping to see some keen records Gentlemen : hung up. I built one of your Low Loss This is the Pickups Pages of RADIO Tuners, and I must report the won- AGE magazine signing off until the derful results I have had with it. I September, 1924, issue. (Now-watch Build a Super -Het have built several hookups since I this -we're going to sign off like WQJ, first built my Low Loss set, to com- Chicago.) PRECEL pare it with for results, and I pick it Don't go away, as "the berries" of the lot. I have This much we have to say: Super Kit one step of audio frequency and work We'll be back, just twice as strong, Iurlud in4 fixed coupler. o.cillator coil, filter, three all the strong stations within 500 Some fine September day mtrrmeliate wave R. F. Transformers. blur print . - panel lasut, etc Complete Kit li,t $25.00 each miles on the loud speaker. The night Letters, Circuits, Everything. before last I had station WBAP of With diagrams complex, It Works and Can't Be Beat ! Fort Worth, Texas, at 10:15 P. M. We're going to help most everyone Order now, as supply is limited. louder than in the Winter time. To get the best DX. Electrical Manufacturer's Agency, Inc. Fine for time of the year. only costs you two bits this It 25 N. Dearborn St. CHICAGO All the big sets about here can bag To tune in on our wave; no distance at all. You can be in Troy or Fargo COMET BATTERIES I have tried out a great many grid And a connection can be made. leaks, but have tried nothing higher We'll have stuff from California, than 3 megohms. I wonder what the We'll have stuff from New York, too; results would be in trying something From Portland down to Cuba higher? You'll hear us calling you; HUDSON -ROSS I certainly want to recommend We'll have the finest line of radio Sells only nationally adver- your RADIO AGE, and want to In our next month's Pickups Page; tised radio apparatus. thank you for printing the descrip- You can tune in strong. - Send for discounts. tion of the Low Loss Tuner. I have You can't go wrong 123 W. Madison St. Chicago convinced several fellows around With a copy of RADIO AGE. THE LAST WORD IN AERIALS THE GREATEST IMPROVEMENT IN RADIO WITHIN THE PAST YEAR Here it is at last -the very thing you have been looking for -a Non - Directional Aerial that can be used anywhere and on all makes of receiving sets. No longer is it necessary to string unsightly wires or be bothered with cumbersome aerials that pick up only from certain directions. THE PORTABLE GLOBE AERIAL, as the name indicates, is not only portable but collapsible, ornamental and, above all, mechanically perfect, , Patent Pending bringing in messages no matter where from or how far away. No. 690459 It Is the Only Aerial That Is Non -Directional Quick installation is another feature. It can be installed and used on the roof, hung out of the window, or in any room at home, at the cffice, in hospitals, on trains or sh'ps, or out in the woods and summer camp, especially adapted for tourists. In its operation it is more selective and tunes much sharper and clearer with less static. The Portable Globe is the only Aerial to use in congested cities and crowded apartments where usually the interference is great, but which interference with the Globe is entirely eliminated. It is made of the finest Phosphor Bronze Spring wire with the Duco water and weatherproof finish- attractive as well as serviceable -a wonderful value, fea'ured at a price within the range of everyone. ORDER TODAY -SATISFACTION GUARANTEED Send in your order now. Be among the first to show your friends the latest and greatest improvement in radio. Send money order or will Parcel post prepaid to your ship C. O. D. door. THE PORTABLE GLOBE AERIAL CO. 1600 Locust Street St. Louis. Mo. Open "An Attractive Proposition to Jobbers and Dealers Who Order in Quantities." Closed

Always dfenliop RADIO AGE II hen Writing to Advertisers RADIO AGE for August, 1924 The Magazine of the lloffr Corrected List of U. S., Cuban and Canadian Broadcasting Stations Complete Each Issue

THE list of broadcasting stations on these pages is brought tip to date each month by additions of new stations and deletion of those which have suspended operation. The list is the product of a vast volume of correspondence and its completeness is due in large measure to the assistance of our special news service in Washington, D. C. Suggestions, corrections and additional data will be welcomed from readers and broadcasters.

KDKA Westinghouse Electric & Mfg. Co East Pittsburgh 326 KFOC First Christian Church Whittier. Calif. 236 KDPM Westinghouse Electric & Mfg. Co. Cleveland, Ohio 270 K FOD Vern Peters .Wallace. Idaho 224 KDPT Southern Electrical Co. San Diego. Calif. 244 KFOJ Moberly High School Radio Club Moberly. Missouri 246 K DYL Telegram Publishing Co Salt Lake City. Utah 360 K FOL Leslie M. Schafbush Marengo. Iowa 234 K DYM Savoy Theatre San Diego. Calif. 244 K FON Echophone Radio Shop Long Beach. Calif. 234 KDYQ Oregon Institute of Technology Portland. Oreg. 360 KFOO Latter Day Saints University Salt Lake City. Utah 261 KDZB Frank E. Siefert Bakersfield, Calif. 240 KFOQ Ora William Chancellor Galveston. Texas 240 KDZE Rhodes Department Store Seattle. Wash. 270 KFOR David City Tire & Electric Co David City. Nebraska 226 KDZI Electric Supply Co. Wenatchee. Wash. 360 KFOT College Hill Radio Club Wichita. Kansas 231 KDZR Bellingham Publishing Co Bellingham. Wash. 261 KFOU Hammel Mfg. Co Richmond. Calif. 254 KFAD McArthur Bros. Mercantile Co. Phoenix. Ariz. 360 KFOX Board of Education. Technical high School Omaha. Nebraska 248 KFAE State College of Washington Pullman. Wash. 330 KFOY Beacon Radio Service St. Paul. Minn. 226 KFAR Studio Lighting Service Co. (O. K. Olsen) Hollywood, Calif. 280 KFOZ Leon Hudson Real Estate Co Fort Smith. Ark. 233 KFAW The Radio Den (W. B. Ashford) Santa Ana. Calif. 280 KFPB Edwin J. Brown Seattle, \Nash. 224 K FAY W. J. Virgin 1 Medford, Oreg. 283 KFPG Garretson and Dennis Los Angeles, Calif. 238 KFBB F. A. Buttrey & Co t Havre, Mont. 360 KFPH Harold Chas. Mailander Salt Lake City. Utah 242 KFBC W. K. Azbill San Diego. Calif. 278 KFPL C. C. Baxter. Dublin, Texas 242 KFBE Reuben H. Horn can Luis Obispo. Calif. 242 KFPM The New Furniture Co Greenville, Texas 242 KFBG First Presbyterian Church Tacoma, Wash. 360 KFPN Missouri National Guard Jefferson City. Mo. 242 KFBK Kimball-Upson Co Sacramento. Calif. 283 KFPP G. & G. Radio & Electric Shop Olympia. Washington 236 KFBL Leese Bros Everett. Wash. 224 KFPQ Clifford M. Ester Denison, Texas 231 KFBS Trinidad Gas & Electric Supply Co. and the Chronicle News KFPR Los Angeles Co. Forestry Dept Los Angeles, Calif. 231 Trinidad. Colo. 360 KFPS Carter A. Ross Motor Service Co Casper, Wyo. 242 KFBU The Cathedral (Bishop N. S. Thomas) Laramie. Wyo. 283 KFPV Heintz & Kohlmoos. Inc San Francisco, 'Calif. 236 KFCB Nielson Radio Supply Co. Phoenix. Ariz. 238 KFPW St. Johns M. E. Church. S Carterville. Mo. 268 KFCF Frank A. Moore Walla Walla, Wash. 360 KFPY Symons Investment Co Spokane. Wash. 283 KFCH Electric Service Station (Inc.) Billings. Mont. 360 KFPX First Presbyterian Church Pine Bluff, Ark. 242 KFCP Ralph W. Flygare Ogden. Utah 360 KFOA The Principia St. Louis, Mo. 261 KFCV Fred Mahaffey. Jr. Houston. Texas 360 KFQB The Searchlight Publishing Co Fort Worth. Tex. 254 KFCZ Omaha Central High School Omaha. Nebr. 258 KFQC Kidd Brothers Radio Shop Taft. Calif. 227 KFDD St. Michaels Cathedral Boise. Idaho 252 KFQD Chovin Supply Co. Anchorage. Alaska 280 KFDH University of Arizona Tuscan. Ariz. 368 KFQE Dickenson -Henry Radio Laboratories. ....Colorado Springs, Colo. 224 KFDJ Oregon Agricultural College Corvallis. Oreg. 360 KFQG Southern Calif. Radio Assn Los Angeles. Calif. 226 K FDR Bullocks' Hardware & Sporting Goods (Rob. G. Bullock ).. V ork. Nebr. 360 KFOH Albert Sherman. Hillsbourgh. Cal. 231 K FDX First Baptist Church Shreveport. La. 360 KFQR Walter LaFayette ItIlis Oklahoma City. Okla. 250 KFDY South Dakota State College of Agriculture and Mechanics Arts KFQI The Thos. H. Ince Corp. Culver City. Calif. 234 Brookings. S. Dak. 360 KFSC Angelus Temple .Los Angeles, Calif. 278 KFDZ Harry O. Iverson Minneapolis Minn. 231 KGB Tacoma Daily Ledger Tacoma. Wash. 252 KFEC Meier & Frank Co. Portland. Oreg. 360 KGG Matlock & Watson Radio Service Portland. Oreg.. 360 KFEL Winner Radio Corp. Denver. Colo. 254 KGO General Electric Co. Oakland, Calif. 312 K FEQ J. L. Scroggin Oak, Nebr. 360 KGU Marion A. Mulrony Honolulu. Hawaii, Waikiki Beach 360 KFER Auto Electric Service Co Fort Dodge. Iowa 231 KGW Portland Morning Oregonian Portland. Oreg. 492 KFEV Radio Electric Shop Douglas. Wyo. 261 KGY St. Martins College (Reb. Sebastian Ruth) Lacy. Wash. 258 KFEX Augsburg Seminary Minneapolis. Minn. 261 KHJ Times -Mirror Co. Los Angeles, Calif. 395 K FEY Bunker Hill & Sullivan Mining and Concentrating Co ... Kellogg. Idaho 360 K HQ Louis Wasmer. Seattle, Wash. 360 KFEZ Asso. Engr. Societies of St. Louis St. Louis. Mo. 248 KJQ C. O. Gould Stockton. Calif. 360 KFFB Jenkins Furniture Co. Boise. Idaho 240 KJR Northwest Radio Service Co Seattle. Wash. 270 KFFE Eastern Oregon Radio Co. Pendleton, Oreg. 360 KJS Bible Institute of Los Angeles Los Angeles. Calif. 360 K FFP First Baptist Church Moberly, Mo. 266 K LS Warner Brothers Radio Supplies Co. Oakland, Calif. 360 K FFR Nevada State Journal (Jim Kirk) Sparks. Nev. 226 K LX Tribune Publishing Co. Oakland. Calif. 509 KFFX McGraw Co. Omaha. Nebr. 278 KLZ Reynolds Radin Co. Denver. Colo. 283 KFFY Pincus Sr Murphy Alexandria. La. 275 KMJ San Joaquin Light & Power Corp. Fresno. Calif. 273 KFGC Louisiana State University Baton Rouge, La. 254 K MO Love Electric Co. Tacoma. Wash. 360 KFGD Chickasha Radio & Electric Co Chickasha. Okla. 248 KNT Grays Harbor Radio Co. (Waller Hemrich) Aberdeen. Wash. 263 KFGH Leland Stanford University GIrnford University. Calif. 273 KNX Electric Tighting Supply Co. Los Angeles. Calif. 360 KFGL Arlington Garage Arlington. Oreg. 234 KOB New Mexico College of Agriculture & Mechanic Arts KFGQ Crary Hardware Co. Boone, Iowa 226 State College, N. Mex. 360 KFGX First Presbyterian Church Orange. Tex. 250 KOP Detroit Police Department Detroit, Mich. 286 KFGZ Emmanuel Missionary College Berrien Springs, Mich. 268 KPO Hale Bros. San Francisco. Calif. 423 KFHA Western State College of Colorado Gunnison, Colo. 252 KQP Apple City Radio Club Hood River. Oreg. 360 KFHD Utz Electric Shop Co. St. Joseph. Mo. 226 KQV Doubleday -Hill Electric Co Pittsburgh Pa. 360 KFHH Ambrose A. McCue Neah Bay. Wash. 283 KQW Charles D. Herrold San Jose, Calif. 360 KFHJ Fallon & Co. Santa Barbara. Calif. 360 KRE V C Battery & Electric Co Berkeley. Calif. 278 KFHR Star Electric Sr Radio Co. Seattle. Wash. 270 KSD Post Dispatch (Pulitzer Pub. Co.) St. Louis. Mo. 546 KFI Earle C. Anthony (Inc.) Los Angeles. Calif. 469 KTW First Presbyterian Church Seattle, Wash. 360 KFID Ross Arhttckle's Garage Iola. Kans. 246 KUO Examiner Printing Co. San Francisco, Calif. 360 KFIF Benson Polytechnic Institute Portland. Oregon 360 KUY Coast Radio Co El Monte, Calif. 256 KFIL Windisch Electric Farm Equipment Co Loulshurg, Kans. 234 KWC Portable Wireless Telephone Co Stockton, Calif. 360 KFIO North Central High School Spokane, Wash. 252 KYQ Electric Shop Honolulu. Hawaii 270 KFIQ Yakima Valley Radio Broadcasting Association Yakima. Wash. 224 KYW Westinghouse Electric & Mfg. Co. Chicago. Ill. 536 KFIU Alaska Electric Light & Power Co Juneau. Alaska 226 KZM Preston D. Allen Oakland, Calif. 360 KFIV V. H. Broyles Pittsburg, Kans. 240 KZN Cope and Johnson Co Salt Lake City. Utah 268 KFIX Reorganized Church of Jesus Christ of Latter Day Saints WAAB Valdemar Jensen . . New Orleans. La. 268 Independence. Mo. 240 WAAC Tnlane University New Orleans. La. 360 KFIZ Daily Commonwealth and Oscar A. Huelsman Fon Du Lac. Wis. 273 WAAD Ohio Mechanics Institute Cincinnati. Ohio 360 KFJR Marshall Electrical Co. Marshalltown. Iowa 248 WAAF Chicago Daily Drovers Journal Chicago, Ill. 286 KFJC Seattle Post Intelligencer Seattle. Wash. 233 WAAK Gimbel Brothers Alilwankee, Wis. 280 KFJF National Radio Alannfacturfng Co. Oklahoma City, Okla. 252 WAAM I. R. Nelson Co. Newark. N. J. 263 KFJI Liherty Theatre (E. E. Marsh) Astoria. Oreg. 252 WARN University of Missouri Columbia. Mo. 254 KFJK Delano Radio and Electric Co Bristow, Okla. 233 WAAW Omaha Crain Exchanee Omaha. Nehr. 360 KFJL Hardsacg Manufacturing Co Ottumwa. Iowa 242 WABB Harrisburg Sporting, Goods Co Harrisburg, Pa. 266 KFJM University of North Dakota Grand Forks. N. Dak. 229 WABD Parker High School Dayton. Ohio 283 KFJQ Valley Radio. Div. of Elec. Constr. Co. Grand Forks. N. D. 280 WABE Young Men's Christian Association Washington, D. C. 283 KFJR Ashley C. Dixon & Son Stevensville. Mont. (near) 258 WABG Arnold Edwards Piano Co. Jacksonville, Nia. 248 KFJX Iowa State Teachers College Cedar Falls, Iowa 229 WASH Lake Shore Tire Co. Sandusky, Ohio 240 KFJY Tumvall Radio Co. Fort Dodge, Iowa 248 WABI Bangor Railway & Electric Co. Bangor. Me. 240 KFJZ Texas National Guard. One hundred and twelfth Cavalry WA BL Connecticut Agricultural College Storrs. Conn. 283 Fort Worth, Texas 254 WA BM F. E. Doherty Automotive and Radio Equipment Co...Saginaw. Mich. 254 KFKA Colorado State Teachers College Greeley. Colo. 248 WA 130 Lake Avenue Baptist Church. Rochester. N. V. 252 KFKR Brinkley-1 ones Hospital Association Milford. Kans. 286 WABP Robert F. Weinig Dover. Ohio 266 KFKQ Conway Radio Laboratories (Ben Il. Woodruff) Conway, Ark. 224 WABQ Haverford College Radio Club Haverford, Pa. 261 KFKV F. F. Gray Butte. Mont. 283 WABR Scott High School. N. W. B. Foley Toledo. Ohio 270 KFKX Westinghouse Electric & Manufacturing Co Hastings. Nehr. 286 WA BT Holiday -Hal'. Radio Engineers \Vashington. Pa. 252 KFKZ Nassour Bros. Radio Co. Colorado Springs. Colo. 234 WA BU Victor Talking Machine Co. Camden. N. T. 226 K FLA Abner R. Willson Butte. Mont. 283 WABW College of Wooster Wooster. Ohio 234 KFLB Signal Electric Manufacturing Co. Menominee. Alich. 248 WABX Henry B. Joy Mt. Clemens. Mich. 270 KFLD Paul E. Greenlav Franklinton. l.a. 234 WARY John Magaldi, Jr Philadelphia. Pa. 242 KFLE National Educational Service Denver. Colo. 268 WARZ Coliseum Place Baptist Church New Orleans. La. 263 K FLO Bizzell Radio Shop Little Rock. Ark. 261 WBAA Purdue University. West Lafuy.tte. Ind. 360 KFLI) Rio Grande Radio Supply House San Benito. Texas 236 WBAH The Dayton Co. Minneapolis. Minn. 417 KFLV Rev. A. T. Frykman Rockford. Ill. 229 WBAN Wireless Phone Corp. Paterson. N. I. 244 KFLX George Roy Clough Galveston. Tex. 240 WBAO Tames Milltkin University Decatur. Ill. 360 K FLY Fargo Radio Supply Co Fargo, N. Dak. 231 1V BAP Wortham- Carter Publishing Co. (Star Telegram )....Fort Worth. Tex. 476 KFLZ Atlantic Automotve Co Atlantic. la. 273 WBAV Erner & Hopkins Co. Columhus. Ohio 390 KFMO University of Arkansas Fayetteville. Ark. 263 WBAX bum H. Stenger, Jr. Wilkes- Barre. Pa. 360 K FMR Morningside College Sioux City. Iowa 261 WRAY Western Electric Co. New York, N. Y. 492 KFMT Dr. George W. Voting Minneapolis, Minn. 231 WBBA Newark Radio Laboratories Newark, Ohio 240 KFMW M. G. Sateren Houghton. Mich. 266 WBBD Barbey Battery Service Reading. Pa. 234 KFMX Carleton College Northfield. Minn. 283 WBBE Alfred R. Marcy Syracuse. N. Y. 246 KFNF Henry Field Seed Co Shenandoah. Iowa 266 WBBG Irving Vermilya Mattapolsett. Mass. 240 KFNG Wooten's Radio Shop Coldwater. Miss. 254 wing fi J. Irving Bell Port Huron. Mich. 246 Mo. 234 KFNJ Warrensburg Electric Shop Warrensburg. WBBJ Neal Elect Fie Co.. P. E. Neal West Palm Beach. FIa. 258 KFNL Radio Broadcast Assn. Paso Robles. Calif. 240 WBBL Grace Covenant Presbyterian Church Richmond. Va. 283 KFNV L. A. Drake Battery and Radio Supply Shop Santa Rosa, Calif. 234 Lincoln. Ill. 225 KFNX Peabody Radio Service Peabody. Kansas 240 WBBM Frank Atlass Produce Co KFNY Montana Phonograph Co Helena. Montana 261 WBBN Blake. A. B Wilmington, N. C. 275 KFNZ Royal Radio Company Burlingame, Calif. 231 WBBR Peoples Pulpit Asso. Rossville. N. V. T44 RADIO AGE for August, 1924 The Magazine of the Hour 59 Radio Geniuses to Be at 378 DX STATIONS `World's Fair' DX Fans. If you have not logged 300 stations in past six months you need a Kennedy Three The first Radio World's Fair, to be held Circuit Tuner. The Kennedy Tuner logged 378 in Madison Square Garden and 69th stations from September 15th to March 15th, in- the cluding 2L0, London; 5WA, Cardiff, Wales; Regiment Armory, New York City, Sept. CFCN, Calgary, Alberta, Canada; KGW, Port- land, Oregon; KFI and KHJ, Los Angeles, Cali- 22nd to 28th, is attracting the serious at- fornia; KPO, San Francisco, California; KGO and 12 Cells tention of the radio geniuses of the world KLX, Oakland, California. 8a and Kennedy Tuner Takes the Place of 11`to bber scores of them are preparing to in- 3 Honeycomb Coils at $1.40 $ 4.20 troduce their latest inventions at the I Honeycomb Coil Mounting 5.00 coming exposition. 1 23 -Plate Vernier Condenser 5.00 SPECIAL Managers U. J. Herrmann and James F. INCLUDING GLOBE TROTTER $5.00 $14 20 INTRODUCTORY PRICE Kerr have been compelled to enlarge the DIAGRAM For a limited time only, and to introduce this T. J. new and superior Storage "B" Radio Battery to "New Inventions Section" to a size which KENNEDY the Public, we are selling it for $4.00. Regular will allow the exposition of one hundred Radio Globe Trotter Retail Price is $6.00. You save $2.00 by ordering devices. Among the noteworthy American 1360 University Avenue, New York, N. Y. NOW. A finer battery cannot be built than the GUARANTEE: if not satisfied after 30 days discoveries to be shown will be at least will cheerfully return your money. World Storage `B" Battery three different Send for Free Diagram. (12 CELLS -24 VOLTS) instruments designed for To ten million homes with Radio Sets -and to countless mil- the purpose radiocasting lions of prospective buyers -this WORLD Storage 'B" Bat. of "photographs ter, brings anew co,.ception of battery economy and perform. ante. Here is a battery that pays for tself in a few weeks- in motion." Europe will also be well will last for years and cap be recharged at a negligible cost. represented And gouging $2.00 by orderia0 now. in this department. Several BIG JOBS I Nubbde Continental inventors will display new in- $150 to $400 per month for A SuperiorBattery só á cágé men trained in auto. tractor and Has heavy duty 2 1-8 in. X 1 ln. x 1 -4 in. plates and plenty of ventions of a most unusual character. acid circulation. Extra heavy glass jars allow ready observa- electrical fields. You can quali- tion of charge and prevent leakage and seepage of current. Half a dozen recognized wireless engi- fy after eight weeks in the It bolds as charge while idle, at constantvoltage. McSweeny You will find this battery a boon to long distance reception. Schools- -where you It does away with a great many noises eo often blamed on neers are now busily engaged trying to learn byworking with real tools static." Mail your order today. perfect systems for broadcasting pictures on real lobs Instead of studying troni books. Special tuition SEND NO MONEY and it is hoped the world's first program offer. R. R. fare paid. 8 weeks hoard free. Get catalog. orders received.rEXbatteries ER 4 batteeries inlseriiep d(9$ of "Radio Motion Pictures" will be broad- ce $15.00. Pay Expressman after examining batteries McSWEENY per n ul der cast on the opening night of the expo- NOW and save $2.00. Auto. Tractor and Electrical WORLD BATTERY COMPANY sition. SCHOOLS Makers al the famous World Radio "A" Storage Ratter,, Sixty nationally known manufacturers 1219 S. Wabash Ave., Dept. 81. Chicago, Ill. Operating Rohe Auto SAVE BY ORDERING NOW of the United States will have de luxe School at Cincinnati & $2.00 exhibits at the big fair and England, Cleveland Auto School 9th & Walnut. Cincinnati. 0. France, Belgium, Italy, Switzerland and 99 1815 E. 24th. Cleveland, 0. "ROLLS ROYCE Austria will have proper representation Dept. 420 RADIO TUBES in the "Foreign Section." Exhibition Like their name, significant booths of elaborate construction will fill of quality. Durable a n d both big buildings will powerful. Bring in distance to which there be vitti a maximum of volume but one admission charge. and clearness. Type 200..5 Volts, 1 Am- The most attractive feature programs From London to Honolulu pere Detector Tube. Type 20IA...5 Volts, .25 imaginable will be staged every afternoon Ampere Amplifier and De- and evening, which will include a series tector. HAVE YOU BUILT YOUR Type 199...3 -4 Volts, .06 of almost unbelievable overseas tests in Ampere Amplifier and De- tector. which Miss Edith Bennett, the famous Type 199...3 -4 Volts, .06 young American concert star, will partici- Ampere With Standard Base. pate. Miss Bennett is well known to the "Nameless"? Type 12, .1Va Volts, .25 Am- pere Platinum Filament. radio enthusiasts of every land because Amplifier and Detector. "THE ROLLS ROYCE OF of her now historical trans -Atlantic recital Ask Your Dealer or Write RADIO TUBES" ALL last year, which was heard by millions of TYPES $2.50 02...5 Watt people in a hundred or more countries. BREMER -TULLY MFG. CO. $3.00 The Amateur Builders' ALL TUBES GUARANTEED International to w o r k in Radio Frequency. Especially Contest is assuming such huge proportions 532 S. Canal St., Chicago adapted for Neutrody:ae. Reflex and Super- heterodyne Sets. that the show management expects this SHIPPED PARCEL POST C. O. D. WHEN ORDERING MENTION TYPE. feature alone to fill the entire basement ROLLS ROYCE TUBE CO. of Madison Square Garden. 21 Norwood St. (Dept. A) Newark, N.J. WorkRite Opens Los Angeles CLASSIFIED ADVERTISEMENTS Branch Ten cents per word per Insertion, in advance. Name and address must be counted. Each initial remits To take care of the tremendous demand as one word. Copy must be received by the 10th of for WorkRite radio sets on the Pacific for month's issue. month succeeding Coast, the WorkRite Manufacturing RADIO CIRCUITS NEW CRYSTAL DETECTOR Company of Cleveland have recently for Neutrodyne Set. SPECIAL FOR AUGUST The Relnartz Radio Booklet, by Frank D. Pearne. opened a branch in Los Angeles, where Reduces static effect. To be used in $ A place of detector tube. Special fully illustrated. and RADIO AGE, for $2.50. Price will WorkRite five - price, `i of booklet alone is SOc. Send check, currency or money they manufacture See and hear WELTY'S loud speak( r. order to RADIO AGE. 500 N. Dearborn Street, Chicago. tube super -neutrodyne sets. WM. A. WELTY CO. 36 So. Stale St. Chicago Dealers Correspondence Invited. RADIO EQUIPMENT. This Pacific Coast factory is under the WHOLESALE PRICES ON STANDARD RECEIVERS. direction of Emmet R. Patterson, who is 25% discount; list for stamp. LIVE PROPOSITION to DEALERS. Thomas Radio Co.. 111a Dix St.. well known to the Western trade. Muncie, Ind. With the establishment of this Pacific YOUR SUBSCRIPTION RADIO BATTERIES Coast factory branch, the WorkRite com- Super Radio A and B Circuit Batteries. which bring in -should be renewed as soon as it long distance reception. Sold for cash or on payment pany have also opened a Western sales plan. Write for prices and details. Radio Battery expires, so you won't miss a single Corporation, 501 -B Industrial Bank Bldg., Flint. Mich. office in Los Angeles, at 239 Los Angeles MISCELLANEOUS street. This branch of the business is issue of RADIO AGE. Order your 158 GENUINE Foreign Stamps. Mexico War Issues. managed A. Hymer, sales manager. September copy in advance if you Venezuela, Salvador and India Service. Guatemala, by J. China. etc.. only 5c. Finest approval sheets 50 to Mr. Hyman has just completed a trip buy from a news -stand, or you may 60'1, Agents Wanted. Big 72 -p. Lists Free. We Buy Stamps. Established 20 Years. Huasman Stamp Co., over the entire Western territory and miss the all -star September issue Dept. 152, St. Louis. Mo. writes that the Los Angeles factory will QUALITY PRINTING -00 hood letter heads, $1.50; with the new Radio Technical Fea- 250 envelopes. $1.50: 250 cords. $1.25. Samples. Mid- be hard pressed to meet the demand for ture originated by RADIO AGE. land Press, 543 West Hickory, Kankakee, Ill. Work-Rite sets during the coming season. Always Mention RADIO AGE When Writing to Adrrrtisrr 60 RADIO AGE for August, 1924 The Magazine of the Hour Corrected List of U. S , Cuban and Canadian Broadcasting Stations

WBBT Lloyd Brothers Philadelphia. Pa. 234 WIAD Howard R. Miller Philadelphia. Pa. 254 WBBU Jenks Motor Sales Co. Monmouth. III. 224 WIAH Continental Radio & Mfg. Co. Newton, Iowa 258 WBBV Johnstown Radio Co Johnstown, Pa. 248 WIAK Journal -Stockman Co Omaha, Nehr. 278 WRBW Ruffner Junior Hielt School Norfolk, Va. 222 WIAO School of Engineering of Milwaukee Alil.vattkce, Wis. 246 WBBY Washington Light Infantry, Co. "B" 118th InL. Charleston, S. C. 268 WIAQ Chronicle Publishing Co. Marion, Ind. 226 WBBZ Noble B. Watson Indianapolis. Ind. 227 WIAS Home Electric Co. Burlington. Iowa 283 WBL T & H Radio Co Anthony. Kans. 254 WIAT Leon T. Noel - Tarkio, Mo. 360 WBR Pennsylvania State Police Butler, Pa. 286 WIAU American Trust & Savings Bank Le Mars, Iowa 360 W BS D. W. May Inc. Newark. N. J. 360 WIAY Woodward & Lothrop Washington. D. C. 273 WBT Southern Radio Corp. Charlotte. N. C. 360 WIK K. & L. Electric Co. (Herbert F. Kelso and Hunter J. Lohman) WBZ Westinghouse Elce. &Mfg. Co. Springfield, Mass. 337 McKeesport. Pa. 234 WCAD St. Lawrence University Canton, N. V. 280 WIL Continental Electric Supply Co. Washington, D. C. 360 WCAE Kaufmann & Baer Co. Pittsburgh, Pa. 462 WIP Gimbel Brothers Philadelphia. Pa. 509 WCAG Clyde R. Randall New Orleans. La. 268 WJAB American Electric Co. Lincoln. Neb. 229 WCAH Entrekin Electric Co. Columbus, Ohio 286 WJAD Jackson's Radio Engineering Laboratories Waco. Texas 360 WCAJ Nebraska Wesleyan University University Place. Nebr. 360 WJAG Norfolk Daily News Norfolk, Nebr. 283 WCAK Alfred P. Daniel Houston. Texas 263 WJAK Clifford L. White Greentown, Ind. 254 WCAL St. Olaf College 'Northfield. Minn. 360 WJAM D. M. Perham Cedar Rapids, Iowa 268 WCAO Sanders & Stavman Co. Baltimore. Md. 360 WJAN Peoria Star Peoria. III. 280 W CA P Chesapeake & Potomac Telephone Co. Washington, D. C. 469 WJAQ Capper Publications Topeka. Kans. 360 WCAR Alamo Radio Electric Co. San Antonio, Tex. 360 WJAR The Outlet Co. (J. Samuels & Bro.) Providence. R. I. 360 WCAT South Dakota State School of Mines Rapid City. S. Dak. 240 WJAS Pittsburgh Radio Supply House Pittsburgh, Pa. 250 WCAU Durham & Co. Philadelphia. Pa. 286 WJAX Union Trust Co. Cleveland. Ohio 390 WCAV T. C. Dice Electric Co Little Rock. Ark. 360 WJAZ Chicago Radio Laboratory Chicago, Ill. 448 WCAX University of Vermont Burlington. Vt. 360 WJD Richard H. Howe Granville, Ohio 229 WCAZ Carthage College Carthage, Ill. 246 WJY R. C. A. New Vork, N. V. 405 WCBA Charles W. Heimhach Allentown, Pa. 280 WJZ R. C. A New York, N. V. 455 WCBC University of Michigan Ann Arbor. Mich. 280 WKAA H. F. Paar Cedar Rapids, Iowa 268 WC BD Wilbur G. Votiva Zion, Ill. 345 WKAD Chas. Looff (Crescent Park) East Providence. R. I. 240 WCBE Ultalt Radio Co New Orleans, la. 263 WKAF W. S. Radio Supply Co Wichita Fells, Texas 360 WC BF Paul J. Miller Pittsburgh. Pa. 236 WKAN United Battery Service Co. Montgomery, Ala. 226 WCBG Howard S. Williams (Portable) Pascagoula, Miss. 236 WKAP Dutee W. Flint Cranston, R. I. 360 WCBI Nicoll. Duncan & Rush Bemis, Tennessee 226 WKAQ Radio Corp. of Porto Rico San Juan. P. R. 360 WCBJ J. C. Maus Jennings. Louisiana 244 WEAR Michigan Agriculture College East Lansing. Mich. 280 WCBK E. Richard Hall St. Petersburg, Fla. 266 WKAS 1.. E. Lines Music Co Springfield, Mo. 360 WCBL Northern Radio Mfg.. Co Houston, Me. 280 WKAV Laconia Radio Club Laconia. N. H. 254 WCBM Charles Swarz Baltimore Md. 229 WKY WKV Radio Shop Oklahoma, Okla. 360 WCBN James P. Boland. Ft. Benj Harrison. Ind. 266 WLAG Cutting & Washington Radio Corp. Minneapolis. Minn. 417 WCBG The Radio Shop, Inc. Memphis. Tenn. 250 WLAH Samuel Woodworth Syracuse. N. V. 234 WCBQ First Baptist Church Nashville, Tenn. 236 WLAL Naylor Electrical Co. Tulsa, Okla. 360 WCRR University of Mississippi near Oxford. Miss. 242 WLAP W. V. Jordon Louisville. Ky. 360 WCBR Charles II. Meester (Portable Station) Providence. R. I. 246 WLAQ Arthur E. Shilling Kalamazoo. Mich. 283 WCBT Clark University. Colleefate Dept Worcester. Mass. 238 WLAV Electric Shop Pensacola, Fla. 254 WCBU Arnold Wireless Supply Co Arnold. Pa. 254 WLAW Police Dent.. City of New York New York. N. Y. 360 WCRV Tullahoma Radio Club Tullahoma, Tenn. 252 WLAX Putnam Electric Co. (Greencastle Comuumity Broadcasting Station) WCRW George P. Rankin. Jr.. and Maitland Soloman - Macon. Ga. 226 Greencastle. Ind. 231 WCBX Radio Shop of Newark (Herman l.ubinaky) Newark. N. J. 233 WLB University of Minnesota Minneapolis, Minn. 360 WCBY The Forks Electrical Shop Buck Hill Falls, Pa. 268 WLS Sears, Roebuck and Co. Chicago, Ill. 345 WCBZ Coppotelli Bros. Musie House Chicago Heights. Ill. 248 WLW Crosley Manufacturing Co Cincinnati. Ohio 309 WCK Stix. Baer & Fuller Dry Goods Co St. Louis. Mo. 360 WMAC J. Edw. Page (Olive B. Meredith) Cazenovia. N. V. 261 WCX Detroit Free Press Detroit. Mich. 517 WMAF Round Hills Radio Corp. I))rttnouth, Mass. 360 WDAE Tampa Daily Times T tmpa, Fla. 360 WMAH General Supply Co. Lincoln. Nebr. 254 WDAF Kansas City Star Kansas City. Mo. 411 WMAK Norton Laboratories Lockport, N. V. 273 WDAG J. Laurence Martin Amarillo. Tex. 263 WMAL Trenton Hardware Co. Trenton, N. T. 256 WDAH Trinity Methodist Church (South) El Paso. Tex. 268 WMAN First Baptist Church Columbus. Ohio 286 WDAK The Courant Hartford. Conn. 261 WMAP Utility Battery Service Easton. l'a. 246 WDAR Lit Brothers Philadelphia. Pa. 395 WMAQ Chicago Daily News Chicago, Ill. 448 WDAS Samuel A. Waite Worcester, Mass. 360 W M A V Alabama Polytechnic Institute Auburn, Ala. 250 WDAU Slocum Kilburn . New Bedford. Mass. 360 WMAY Kingshiahway l'resbyterian Church St. Louis. Mo. 280 WDAY Radio Equipment Corp Fargo, N. Dak. 244 WMAZ Mercer University Macon, Ga. 261 WDBA Fred Ray Columbus. Ga. 236 WMC ' Conmercial Appeal" (Commercial Publishing Co.). .ltlemnhie, Tenn. S00 W DBB A. H. White & Co.. Inc Taunton, Mass. 229 WMH Precision Equipment Co Cincinnati. Ohio 248 WDBC Kirk. Johnson & Co. Lancaster. Pa. 258 WMU Doubleday-Hill Electric Co. Washington, D. C. 261 W nun Herman Edwin Burns Martinsburg, W. Va. 268 WNAC Shepard Stores Boston. Mass. 278 W DBE Gilham- Schoen Elect ric Co Atlanta. Ga. 252 WNAD University of Oklahoma ...... Norman. Okla. 360 WDBF Roherl G. Phillips .Votingstown, Ohio 246 WNAL R. J. Rockwell Oinaha, Nebr. 242 WDRH C. T. Scherer Co Worcester. Mass. 268 WNAM Ideal Apparatus Co Evansville. Ind. 360 WDBI Radio Specialty Co.. St. Petersburg. Fla. 226 WNAP Wittenberg College Springfield. Olio 231 WDR.1 Richardson Wayland Electric Corp Roanoke, Va. 229 WNAR C. C. Rhodes Butler, Mo. 231 WDBK M. F. Bros Radio Co Cleveland. Ohio 248 WNAT I.ennig Brothers Co. (Frederick Lennie) Philadelphia, Pa. 360 WDBL Wisc. Dept. of Markets ,tevcns Point. Wise. 278 WNAW Peninsular Radio Club (Henry Kutiziiraniii Fort Monroe. Va. 360 wnRN Electric Licht & Power Co. .... Rancor. Me. 252 WNAX Dakota Radio Apparatus Co. Yankton. S. Dak. 244 W DRO Rollins College. Inc Winter Park. Fla. 240 WOAA Dr. Walter Hardy Ardmore. Okla. 360 WnBP Superior State Normal School Superior. Wis. 261 WOAC Maus Radio Co. Lima. Ohio 266 WnBQ Morton Radio Sunply Co. Salem. N. J. 234 WOAD Friday Battery & Electric Corp. Sigourney, Iowa 360 W UBR Tremont Temple Baptist Church .. Boston, Mass. 256 WOAE Midland College Fremont. Nebr. 280

W ORS S. M. K. Radio Corp . Dayton. Ohio 283 WOAF Tyler Commercial College Tyler. Texas 360 WDBT Taylor's Book Store Hattiesburg, Miss. 236 WOAG Apollo Theater (Belvedere Amusenient Co.) Belvedere. Ill. 224 W DBU Somerset Radio Co. Skowhegan. Maine 258 WOAH Palmetto Radio Corp. Charleston, S. C. 360 WDBV The Quimby Enterprises. The Strand Theatre Fort Wayne. Ind. 258 WOAI Southern Equipment Co. San Antonio. Texas 385 WDM Church of the Covenant Washington. D. C. 234 WOAN Vaughn Conservatory of Music (James D. N'aughn) WDZ James L. Bush Tuscola. Ill. Star Store Bldg. 278 Lawrenceburg. Tenn. 360 WEAA F. D. Fallain Flint. Mich. 280 WOAO I.yradion Mfg. Co. Mishawaka, Ind. 360 WEAF American Telephone & Telegraph Co. New Vork. V. V. 492 WOAQ Portsmouth Kiwanis ChM Portsmouth. Va. 360 WF_AH Wichita Board of Trade Wichita, Kans. 244 WOAT Boyd M. Hamy Wilmington, Del. 360 WEAL Cornell University Ithaca. N. V. 286 WOAV Pennsylvania National Guard. 2d Battalion. 112th Infantry..Erie, Pa. 242 WEAJ University of South Dakota Vermillon. S. Dak. 283 World WEAM Borough of North Plainfield (W. Gibson Buttfield) WOAX Franklyn J. Volff Trenton. Neb J. 240 North Plainfield, N. J. 252 WOC Palmer School of Chiropractic Davenport, Iowa 484 WEAN Shepard Co Providence. R. I. 273 WOI Iowa State College Ames. Iowa 360 WEAO Ohio State University Columbus, Ohio 360 WOO John Wanamaker Philadelphia. Pa. 509 WEAP Mobile Rzdio Co Mobile. Ala. 360 WOO Western Radio Co. Kansas City, Mo. 360 WEAR The Evening News Publishing Co Baltimore. Md. 261 WOR L. Bamberger & Co Newark, N. J. 405 WEAU Davidson Bros. Co. Sioux City. Iowa 360 WOS Missouri State Marketing Bureau Jefferson City. Mo. 441 WEAY Iris Theatre (Will Horowitz. Jr.) Houston, Texas 3G0 WPAB Pennsylvania State College State College. Pa. 283 WER Renwooi Co Wit. Loiils, Mo. 273 WPAC Donaldson Radio Co Okntulgee. Okla. 360 WEBC Walter Cecil Bridge. Superior. Wis. 242 WPAJ Doolittle Radio Corp. New Haven. Conn. 268 WEBD Electrical Equipment and Service Co Anderson, Ind. 246 WPAK North Dakota Agricultural College Agricultural College. N. Dak. 283 WEBH Zenith- Edgewater Beach Broadcasting Station Chicago. Ill. 370 WPAL Superior Radio Sc Telephone Equipment Co. Columbus, Ohio 286 WEV Ituriburt -Still Electrical Co Houston, Texas 360 WPAM Auerbach & Guettel Topeka, Kans. 360 WEW St. Lotis University St. Louis. Mo. 261 WPAP Theodore I). Ylülli s Winchester. Ky. 360 WFAA Dallas News & Dallas Journal Dallas. Texas 476 WPAR Ward Battery and Radio Co Beloit, Kans. 236 WFAB Carl F. %Voese Syracuse, N. V. 234 WPAU Concordia College Moorhead. Minn. 286 WFAH Electric Supply Co Port Arthur. Texas 236 WPAZ John R. Koch (Dr.) Charleston. W. Va. 273 WFAM Times Publishing Co St. Cloud. Minn. 360 WQAA Horace A. Beale. Jr. ....- Parkersburg, Pa. 360 WFAN Hutchinson Electric Service Co. Hutchinson, Minn. 360 WQAC E. B. Gish Amarillo, Texas 234 WFAV University of Nebraska. Department of Electrical Engineering WQAE Moore Radio News Station (Edmund B. Moore) Springfield. Vt. 275 Lincoln. Nebr. 275 WQAF Sandusky Register '5:industry. Ohio 240 WFBW Ainsworth -Gates Radio Co Cincinnati, Ohio 309 WQAL Coles County Telephone & Telegraph Co. Mattoon, Ill. 258 WFI Strawhridge & Clothier Philadelphia, l'a. 395 WQAN Scranton Times Scranton. l'a. 280 WGAL Lancaster Electric Supply & Construction Co Lancaster. Pa. 248 WQAO Calvary Baptist Church New York. N. Y. 360 WGAN Cecil E. Lloyd Pensacola. Fla. 360 WQAQ Abilene Daily Reporter (West Texas Radio Co.) Abilene. Texas 360 WGAQ Glenwood Radio Corp. (W. G. Patterson) Shreveport. La. 252 WOAS Prince -Walter Co. Lowell. Mass. 266 WGAW Ernest C. Albright Altoona, Pa. 261 WOAX Radio Egtiintnent Co Peoria. Ill. 360 WGAZ South Rand Tribune South Rend. Ind. 360 WQJ Calumet Baking Powder -Rainbow Gardens Station Chicago, Ill. 448 WGI American Radio & Research Corp. Medlord Hillside, Mass. 360 WRAF The Radio Club (Inc.) Laporte, Ind. 224 WGL Thomas F. T. Howlett Philadelphia. Pa. 360 WRAL Northern States Power Co St. Croix Falls. Wis. 248 WGN Chicago Tribune Broadcasting Station Chicago. Ill. 360 WRAM Lombard College Galesburg, III. 244 WGR Federal Telephone & Telegraph Co. Buffalo, N. V. 319 WRAN Black Hawk Electrical Co. Waterloo, Iowa 236 WGY General Electric Co. Schenectady, N. V. 380 WRAO Radio Service Co. St. Louis Mo. 360 WHA University of Wisconsin Madison, Wis. 360 WRAV Antioch College Yellow Springs. Ohio 242 Wt4AA State University of Iowa Iowa City. Iowa 484 WRAW Avenue Radio Shop (Horace D. Good) Reading. l'a. 238 WHAD Marquette University Milwaukee. Wis. 280 WRAX Flaxon'_ Garage Gloucester City, N. J. 268 WHAG University of Cincinnati Cincinnati. Ohio 222 WRBC Imanuel Lutheran Church Valparaiso. Ind. 278 WHAH Hafer Supply Co Joplin. Mo. 283 WRC Radio Corporation nl America Washington. D. C. 469 WHAK Roberts Hardware Co. Clarksburg. W. Va. 258 WRH Chicago Herald & Examiner Chicago. Ill. 536 WHAM University of Rochester (Eastman School of M uric)... Rochester. N. V. 283 iWRK IMron Bros. Electric Co. Hamilton. Olio 360 WHAP Cita & Kuhns Decatur, Ill. 360 WRL Union College Schenectady, N. V. 360 WHAR Paramount Radio & Electric Co. (W. H. A. Pules) WRM University of Illinois Urbana. Ill. 360 Atlantic City. N. l. 231 WRR City of Dallas (]calice and fire signal department) Dallas, Texas 360 WHAS Courier- Journal & Louisville Tintes Louisville. Ky. 400 WRW Tarrytown Radio Research Laboratory (Koenig R ram. ). Ta rrytown.N. V. 273 WHAV Wilmington Electrical Specialty Co. Wilmington, Del. 360 WSAB Southeast Missouri State Teachers College Cape Girardeau. Mo. 360 WHAZ Rensselaer Polytechnic Institute Troy. N. V. 380 WSAC Chanson Agricultural College Clemson College, S. C. 360 WHB Sweeney School Co Kansas City. Mo. 411 WSAD .1. A. Foster Co Providence, R. 1. 261 WHK Radiovox Co. (Warren R. Cox) Cleveland, Ohio 360 WSAI United States Playing Cards Co. Cincinnati. Ohio 309 WHN George Schuhe) New York. N. V. 360 WSAJ Grove City College Grove City. Pa. 259 WHO Bankers Life Company Des Moines. Iowa 526 WSAN Allentown Radio Club Allentown. Pa. 229 WIAB Jo.tyn Automobile Co Rockford. Ill. 252 WSAP Seventh Day Adventist Church New York, N. Y. 263 WIAC Galveston Tribune Calveslon, Texas 360 WSAR Douanty Sr Welch Electrical Co Fall River. Mass. 254 RADIO AGE for August 1924 The Magazine of the Hour 61 Breaking Into Radio Without but for a simple and easily comprehended a Diagram "starter" in radio reception, the board layout is unbeatable. Fig. 2 gives the final (Continued from page 12) appearance, and the set is a simple and WANTED electric light current, but permits radio sure receiver that will in most locations OPPORTUNITY to become as- currents to pass unimpeded. not only respond to local stations, but will sociated with livest radio sales at times bring in plenty organization in the west. Must be With your "aerial" connected, turn on of distance for financially able to pay for sample the rheostat again and proceed to "tune you. With the phone line or with an outline. Opportunity to make real in." Vary the condenser over its range side aerial, "DX" stations are easily heard money. First replies will be given as before and follow up with variometer, with this regenerative arrangement, and preference. Address trying to avoid actual oscillation. You for sharp tuning and for volume, even should look up the broadcasting hours of though your aerial is small, or if you use Welbar Mfg. Co. the nearby stations beforehand to be sure the lighting circuit or bell wiring, you'll 53 W. Jackson Blvd. Chicago there is something "on the air." A whistle be pleased with your first plunge into the is a sign that your tube is oscillating, and most fascinating game of them all. the variometer setting should be changed until it stops. By this time you will have KEEPING UP -TO -DATE tuned in a station or two and will have a No Radio Conference This Summer For the latest radio inventions better understanding of the relationship [By Washington between condenser and variometer. Al- Radio News Service] RADIO AGE readers should ways think of the condenser as the Just before Secretary Hoover left the keep a close watch on the "New "tuner," or the device which selects the city last week for a two -month vaca- and Novel Radio Patents" de- station you wish to hear. The variometer tion it became known that he would not partment beginning in this issue. is the "volume" control, for it determines call the third radio conference before Up -to -date every month. the sensitiveness of your set. A loud howl September. may result if the variometer if turned too far. The "Circuits" -cA Calibrated Grid Leak!! adjust it for best resulis. You read the resis- During the wiring, you noticed that sev- You set it for a specified resistance and alit; mcgohm through a.peep.hole in the panel. (It's eral "circuits" were referred to. The cur- tance in exact terms of the handcalibrated in table mounting.) Each FIL.KO.LEAK is individually equipped for and is not affected by rent set up in the phone or lighting wires Resistance element is constant and accurate, the laboratory. assures you smooth, gradual atmospheric conditions or swear. The FIL .KO.LEAK by the wave from the broadcasting station distant and local stations with greater clarity control of resistance. You s,1 :1 get both passes through the condenser "1" and for when the negative bias on the grid of the detector and volume than ever before, nor "spills over ". Is precisely right the rube neither "chokes" thence through the primary coil "2," to tube the avcakest stations. The improvement will be most noticeable on the earth at "G." As these radio currents and me. is guaranteed to be perfect electrically in coil in the §2.00 Every FIL.KO.LEAK the operating range fluctuate "2" accordance with and to be accurately calibrated over chanically, is doubly checked voice or music from the station, there is for all tubes 04 to 5 megohmst. This calibra:ion a magnetic field spreading out and then before the instrument is shipped. collapsing back again in the space around that coil just as there is a magnetic field (though steady) surrounding the ordinary horse -shoe magnet. As a matter of fact, 'alINAL POSTS FIL -Lrix current set up by a great many broadcast- 'mot SCIENTIFICALLY CORRECT THE STANDAPO LEAK ing stations is passing through coil "2" at Calls !-- VARIABLE. ORID COMDrNSESS the same time. It is the function of the secondary circuit with coil "3" and vari- -With -Simple able condenser "4" to pick out which sta- -With Battery Sturdy tion is desired. If the station is sending the Switch Sure on 300 meters, not very much of the ca- % pacity of condenser "4" will be required, $100 Attached but if the wave length is longer, say 500 Guarantee Carries the usual meters, more of the capacity is necessary Supremacy Fu KOrARrs and the plates must be moved further in, proven by 50c unconditional every test tee. perhaps as shown in Fig. 2. The magnetic 1.50 g te ui.,,r field from coil "2" sets up current in coil A single-hole mounting "A" Battery "3" ,., ;witch tu al's easy le attach. once the latter has been "tuned" to Bakelite U1 se.... " the right wave length by the condenser. Insulation Wiping contacts assure clean, posi- Hermetically .tee connection when the switch it Then through the tube and the variometer, Solid un the "On" position. When the Sealed Bran the energy is very greatly amplified. It The only compression type rheostat snitch is "Off". the contacts have a Mounting with a battery switch attachment. positive break and are separated by is really not the actual energy which comes Bracket Combines the advantages of infinite highest quality insulating material. control of filament current with Ow in on the aerial which actuates the mag- Absolutely warranted to protect your The end terminals of the switch can :simplicity or an ordinary loaner) set from lightning, with a guarantee be used for solder connections. or nets in your telephone receivers, but the ...nth. And al no extra eust! If to pay you S 100 or to rrpahr ymtr xb connecting wires can be hehl in son want perfect control of any current from the "B" battery. The tube should it be damaged through rattily place by She screws provided for hspe tube in any hook-up you operation of the errr,lrr -if that purpose. is a valve through which a slight impulse ...cot freedom from tube noises -. The "umbrella"' from the broadcasting station causes a shield keep. dull of )on want f)\ stations yon never The niekrl knob and the entire hous- nisturr, elf.. from the until heard before - macimum signal ing are insulated front the ten uivals great variation of the "B" battery current presenting leakage lusses f' aerial -trengtlh- longer tube and battery in that any wires accidentally corn to ground. This makes certain tut Iifesthen you in the telephones. newt use nt.KO-sTAT. Mg in enntact wills any part or the all radio impulses reading the am Belly') switch attaches to regular switch outside of the terminals then,. leona pass through set. It is a good plan to fasten a stiff wire ynr whirler i a- KO.STST mounting screws. No selves ran caux no damage. assures maximum reception as a pointer for the dial of the condenser. elra holes D, drill. It may be attached to one of the mounting screws and allowed to project past the FI L-KO-ARRÉSfiR FI SCIENTIFICALLY CORRECT FILIO-STAT L-KO-SWITC rim at some convenient point. Then the SCIENTIFICALLY CORRECT . SCIENTIFICALLY CORRECT 10 UGHTN1NG ARRES RADIO RHEOSTAT 'Ä'BATTERY dial should be set to read "100" when the = SWITCH movable plates are all the way enmeshed \_4 between the fixed plates, and there the :Z114 1HI1 _ flIIIIYAIfIS capacity is a maximum. F.,e. a.pnmNMlves ninnv D COAOANtL,O lit RADIO STORES CORP. Dept. RA824 As your radio knowledge grows there INSTRUMENT 01; uaapsaw..aO ..t.,1 +DX HARRISBURG, PA ire other combinations you will like to try, Neu. York Oars! 1:0 We., )4th le. Always Mention RADIO AGE Whet: 'Veiling to Advertisers 62 RADIO AGE for August, 1924 The Magazine of the hour Corrected List of U. S., Cuban and Canadian Broadcasting Stations WSAU Camp Marienfeld Chesham,N. H. 229 WTAS ('harles E. Erbstein Elgin. Ill. 275 WSA X Chicago Radio Laboratory Chicago. ill. 268 WTAT Edison Electric Illuminating Co. Boston. Mass. (portable) 244 WSA Y Irving Austin (Port Chester Chamber of Commerce) . Port Chester, N. Y. 233 WTAU Ruegg Battery & Electric Co. Tecumseh. Nebr. 360 WSAZ Chas. Electric Shop Pomeroy. Ohio 258 WTAU Ruegg Battery & Electric Co Tecumseh, Nebr. 242 WSB Atlanta Journal Atlanta. Ga. 429 WTAW Agricultural & Mechanical College of Texas College Station. Tex. 280 J. & M. Electric Co Utica. N. Y. 273 WTAX Williams Hardware Co. Streator. Ill. 231 WS Alabama Power Co Birmingham. Ala. 360 \VTAY Oak Leaves Broadcasting Station Oak Park. Ill. 283 WTAB Fall River Daily Herald Publishing Co. 17-111 River, Mass. 248 WTAZ Thomas J. McGuire Lambertville, N. J. 283 WTA C Penn Traffic Co Johnstown, Pa. 360 WTG Kansas State Agricultural College Manhattan. Kans. 273 WTAF Louis J. Gallo New Orleans, La. 242 W VAB Hoenig, Swern & Co. (John Rasmussen) Trenton, N. J. 220 WTAG Kern Music Co Providence. R. 1. 258 WWAD Wright & Wright (Inc.) Philadelphia, Pa. 360 WTA FI Carmen Ferro Belvedere. III. 236 WWAE Alamo Dance Hall. L. J. Crowley Joliet. Ill. 227 WTAJ The Radio Shop Portland, Me. 230 WWAO Michigan College of Mines Houghton, Mich. 244 WTAL Toledo Radio Sr Electric Co Toledo. Ohio 252 WWI Ford Motor Co Dearborn. Mich. 273 WTAM Willard Storage Battery Co Cleveland. Ohio 390 WWJ Detroit News (Evening News Assn.) Detroit. Mich. 517 WTA P Cambridge Radio & Electric Co. Cambridge, 111. 242 WWL Loyola University . New Orleans. La. 260 WTAQ S. H. Van Gordon & Son Osseo, Wis. 220 WYAM Electrical Equipment Co Miami. Fla. 283

WTAR Reliance Electric Co Norfolk, . Va. 280 WYAW Catholic University Washington. D. C. 236 Canadian Stations CFAC Calgary Herald C-tlgary, Alberta 430 CHCM Riley & McCormack Calgary. Alberta 415 CFCA Star Pub. & Prtg. Co. s Toronto. Ontario 400 CHCS The Hamilton Spectator Hamilton. Ont. 420 CFCF Marconi Wireless Teleg. Co. of Canada Montreal. Quebec 440 CHYC Northern Electric Co Montreal. Quebec 410 CFCH Abitibi Power & Paper Co. Iroquois Falls. Ont. 400 CJCA Edmonton Journal Edmonton. Alberta 450 CFCJ La Cic de L'Evenement Quebec. Quebec 410 CJGC London Fre- Press Prtg. Co. London. Ont. 430 CFCK Radio Supply Co Edmonton. Alberta 410 CJCD T. Eaton Co. Toronto. Ont. 410 CFCL Centennial Methodist Church Victoria. British Col. 400 CJCE Sprott -Shaw Radio Co. Vancouver, B. C. 420 CFCN W. W. Grant Radio (Ltd.) Calgary. Athena 440 CJCI Maritime Radio Corp. St. John New Brunswick 400 CFCQ Radio Specialties (Lid.) Vancouver. B. C. 450 CJCM J. L. Phillipe Monti Jolt. Quebec 430 CFCR Laurentidc Air Service Sudbury. Ont. 410 CJCN Simons Agnew & Co. Toronto, Ont. 410 CFCW The Radio Shop London. Ont 420 CJSC Evening Telegram Toronto. Ont. 430 CFDC Sparks Co Nanaimo, B. C. 430 CKAC La Presse Puh. Co Montreal. Quebec 430 CFQC The Electric Shop (Ltd.) ti-t skatoon. Saskatchewan 400 CKCD Vancouver Daily Province Vancouver, B. C. 410 C FR C Queens University Kingston. Ontario 450 CKCE Canadian Independ. Telephone Co Toronto, Ont. 450 CFUC University of Montreal Montreal. Quebec 400 CKCH Canadian National Railways Ottawa, Ont. 435 CHAC Radio Engineers 4. Halifax, Nova Scotia 400 CKCK Leader Putt. Co Reina, Saskatchewan 420 CHBC Albertan Publishing Co. Calgary. Alberta 410 CKCO Ottawa Radio Association Ottawa. Ont. 440 CHCB Marconi Company. Toronto, Ont. 410 CKCX P. Burns & Co Calgary, Alberta 445 CHCD Canadian Wireless & Elec. Co Quebec. Quebec 410 CKLC Wilkinson Electric Company . Calgary. Alberta 400 CHCE Western Canada Radio Sup. (Ltd.) Victoria, B. C. 400 CKOC Wentworth Radio Supply Co Hamilton, Ont. 410 CHCL Vancouver Merchants Exchange Vancouver, B. C. 440 CKY Manitoba Telephone System Winnipeg. Manitoba 450 Cuban Stations PWX Cuban Telephone Co - I labana 400 2 HS 2 DW Pedro lava- Habana 300 20L OslcarPCollado Habana 290 2AB Alberto S. dc Bustamantc Habana 240 2WW Amadeo Saenz Habana 210 20K Mario Garcia Velez Habana 360 SEV Leopoldo V. Figueroa Colon 360 2BY W. Borton 6K W Frank H. Jones Tuinucu 340 Frederick Habana 260 6K J Frank H. Jones Tuinucu 275 2CX Frederick W. Borton Habana 320 6CX Antonio T. Figueroa Cienfiegos 170 2EV Westinghouse Elec. Co Habana 220 6DW Eduardo Terry Cienfiegos 225 2TW Roberto E. Ramires Habana 230 6BY Jose Ganduxe Cienfuegos 300 2HC Heraldo de Cuba H-tbana 275 6AZ Valentin Ullivarri Cienfuegos 200 2LC Luis Casas Habana 250 6EV Josefa Alverax Caibarlen 225 2KD E. Sanchez de Fuentcs Habana 350 Alfreda Brocks Stgo de Cuba 240 2MN Fausto Simon Habana 270 86 Alberto Ravelo Stgo. de Cuba 250 2MG Manuel G. Salas Habana 280 8FU Andres Vinnet Stgo. de Cuba 225 2JD Haul Perez Falcon ,. Habana 150 Pedro C. Anduz Stego. de Cuba 275 2Kr Alvara Daza Habana 200 8EV Eduardo Mateos . Stego. de Cuba 180

K F F Q Marksheffel Motor Co.. Col. Springs. Col. KFMU Stevens Brothers, San Marcos. Texas. Status of Broadcasting K F F V Graceland College, Lamoni, Iowa. K F M Z Roswell Broadcasting Club, Roswell. K F G V Heidbreder Radio Supply Co.. Utica, N. M. Stations Falling Off Neb. K F N C Alonzo Monk, Jr., Corsicana. Texas. KFHX Nelson. Robert W.. Hutchinson, Kansas. K F O F Rohrer Electric Co.. Marshfield, Oregon. A survey and house cleaning of broad- K F O H The Radio Bungalow, Portland, Oregon. K F J V Warren. Thomas H.. Dexter, Iowa. K casting stations, completed by the De- K L City. F O P Willson Construction Co., Dallas, Texas. F H Erickson Radio Co., Inc.. Salt Lake K G N Northwestern Radio Mfg. Co.. Portland. partment of Commerce on July 1, Utah. K F L P Everette Al. Foster. Cedar Rapids. Iowa. Ore. a lot of "dead wood" stations, K Z V Wenatchee Battery and Motor Co.. eliminated KFA1 S Freimutlt Dept. Store, Duluth, Minn. Wenatchee, Wash. reducing the total number of broadcasters KFMY Boy Scouts of America, Long Beach. Cal. \vABS Essex Mfg. Co.. Newark. N. J. KFNH State Teachers College, Springfield, Mo. to 534, thirty -nine less than on July 1, wABV DeWitt. John H., Jr.. Nashville, Tenn. K F O V Davis Electrical Corp.. Sioux City. Iowa. W B B Q Frank Crook, Pawtucket, R. 1. last year, and fifty -five less than on June \V ABA Lake Forest University. Lake Forest, Ill. W B B S First Baptist Church, New Orleans, La. WABN Ott Radio Inc., La Crosse. Wis. Villanova 1 this year. WCAAI College. Villanova, Pa. \VBBF Georgia School of Technology, Atlanta. W C M University of Texas. Austin, Texas. Fans should not be alarmed, however, Ga. \VDAO Automotive Electric Co., Dallas, Texas. Limestone & Co., for fear that this popular practice is \VBBO Mich. Chemical \VFAF Spratley, Henry C., Poughkeepsie, N. Y. Rogers. Alice. W G V Interstate Electric Co., New Orleans, La. about to die out. Many of the stations \VCr\S Dunwoody Industrial Institute. Minne- W H A B Thompson, Clark \V., Galveston, Texas. eliminated simply failed to renew their apolis, Minn. W I A F De Cortin. Gustav :\., New Orleans. La. WrAJ Hi Grade Wireless Inst. Co.. Asheville, \V J X De Forest Radio Telephone & Telegraph licenses, and some will again apply for N. C. Co.. New York City. \V F A Q Missouri Wesleyan College and Cameron permission to broadcast it is believed. W L A J Waco Electrical Supply Co., Waco. Tex. Radio Co.. Cameron. Mo. WAIAB Radio Supply Co.. Oklahoma City. Okla. Of the stations which dropped out, 53 \V F A T Columbus College. Sioux Falls, S. Dak. \VNAN Syracuse Radio Telephone Co., Syracuse, were in Class A. and 29 in Class C. No W I A I Heers Stores Co.. Springfield, Mo. N. V. \V IA J Fox River Valley Radio Supply Co., \VNAS Texas Radio Corporation, Austin, Texas. Class B stations quit the air, and there Neenah, \Vis. Peoples Tel. & Tel. Co.. Knoxville, Tenn. Kelley -Vawter Jewelry Co., Marshall, \VNAV are today 54 such, an increase of 12 over \vJAT W N J Sllotton Radio Mfg. Co., Inc.. The, Mo. Albany, N. Y. the number on June 1. There are also WKAY Brenau College. Gainesville, Ga. WOAP Kalamazoo College. Kalamazoo, Mich. \VLAK Vermont Farm Machine Corp.. Bellows 377 Class A stations; 101, C, and 2 in \\r o K Pine Bluff Company. The, Pine Bluff, Falls. Vt. A rk. the experimental Class D, still operating. \vMAJ Drovers Telegram Co., Kansas City. Mo. \V PAT Saint Patricks Cathedral. El Paso, Texas. Nevertheless, the peak of broadcasting, \VNAQ Charleston Radio Elect. Co.. Charleston. WOAD Whitall Electric Co., Waterbury, Conn. S. C. \VRAA Rice Institute, Houston, Texas. on May 1. 1923, totaled 592 stations and WOAR Lundskow. Henry- P.. Kenosha. Wis. \VRAH Read, Stanley N., Providence, R. I. may never again be attained, although the \VQAW Catholic University of America, Wash- WRAY Radio Sales Corp., Scranton, Pa. ington, D. C. \VSAT Donohoo Ware Co., Plainview, Texas. total was only 3 below par, so to speak, W S A G Davis, Loren V., St. Petersburglt, Fla. WWAC Sanger bros., Waco. Texas. WgS A \V John L. Long. Jr.. Canandaigua, N. Y. on June 1, 1924, when 589 were on the \vWAF Galvin Radio Supply Co.. Camden, N. J. air. K F A N Electric Shop. Moscow, Idaho. K FAU Independent School Dist. of Boise City. The eighty -two stations which were Boise, Idaho. dropped from the Department of Com- K FDO Cutting. H. E., Bozeman, Mont. K FDV Gilbreth and Stinson. Fayetteville, A rk. merce active list for various reasons are K F H B A. S. Kolstad, The Rialto Theatre, Hood as follows: River, Ore. HUDSON -ROSS K F H F Central Christian Church. Shreveport, exclusive Radio CALL STATION La. Largest K D Y X Star Bulletin Pub. Co.. Honolulu. T. H. K F F O Smith. Dr. E. H., Hillsboro. Ore. Jobbers in middle West. K D Z Q Nichols Academy of Dancing. Denver, K F F Z Al. G. Barnes Amusement Co.. Dallas, Write for discounts. Col. Texas. K F A F Western Radio Corp., Denver. Col. K F L R University of New Mexico, Albuquerque, 123 W. Madison St. Chicago K F A J University of Colorado, Boulder. Col. N. M. K F C Y Western Union College. LeMars, Iowa. K FL\V Missoula Electric Supply Co.. Missoula. K T) A Adler's Music Store. Baker, Oregon. Mont. RADIO AGE for August, 1924 The Magazine of the Hour 63 Department of RADIO ENGINEERING Radio Age Institute

Tested and Approved 1 BytheDepartment RADIO ENG ÿ ING

.R12I0 CaG INSTITUTE-' esÉt No . Conducted by ` R/,lD1o,G TiYC. ,ch;go, 1u.. u.sA ..,mlrTr:. r/' Look for the Approval Seal Tie above approval seal will be furnished free of charge by RADIO AGE, and any article bearing this seal has been approved by the Institute Laboratory. We will be pleased to receive and test any materials that are offered on the market and give them our endorsement where they meet all Institute tests. Send materials to RADIO AGE IN-

STITUTE, 500 N. Dearborn St., Chicago. . Radio sets and equipment sent to the RADIO AGE INSTITUTE since its inception last month are now being tested in our laboratories. This apparatus includes sets from amateur radio builders as well as the perfected inventions of well known manufacturers. All will be tested, and, if meeting RADIO AGE INSTITUTE requirements, will be given the official approval seal reproduced above and sent back to the maker. This service is absolutely free, and RADIO AGE wishes it understood a test by its INSTI- TUTE does not incur any obligations on the part of the maker, whether he be amateur or manufacturer. Results of the first tests will be announced in the September RADIO AGE, with illustrations.

For Volume and Clarity of Tone Build an Erla Receiver Y Erla Receivers are noted for their distance and almost unbelievable volume.

The naturalness of tone cannot be distinguished from the source of reception. { This is the famous Erla Reflex Hookup. Not quite a year old, it has taken the nation by storm. It is so easy to make that anyone who can handle a screw- a driver can build a set complete in a surprisingly short time -about 1% hours to be exact. Everything is so simple and easy to understand -if you use Erla tl Blue Prints. t;l r Use ERLA BLUE PRINTS No Soldering Needed The results from the Erla 3 -Tube cannot be improved upon. Actual size working diagrams make everything Erla Hookup Diagram Prices simple. Every piece of apparatus and every wire is pictured in its exact place -every article needed is listed 3 Sheets for making 1 -tube set, 25c on the diagrams. 2 Diagrams sent same day order is received. Send P. O. 3 Sheets for making -tube set, 35c Money Order or Bank Draft or Bank Cashier's Check. 3 Sheets for making 3 -tube set, 50c 4 Don't send stamps or personal checks. Frank D. Pearne Sole Distributor of Erla Diagrams for U. S. and Canada 829 Waveland Avenue, Chicago, 111. Dealers, Write for Quantity Prices 4 1-4

Always Mention RADIO AGE When Writing to Advertisers 64 RADIO AGE for August, 1924 The Magazine of the Hour With the Radio Manufacturers (Continued from page 44)

Prest -O -Lite Announces New This raised position of the cell con- So sensitive is this set that, under Radio "B" Battery nectors makes it easy to keep the top of favorable conditions, Havana, Cuba, New the cells A radio "B" battery with many new dusted and looking spick and York City and Jefferson City, Mo., have features has just been announced span. It is td be noticed that the posi- been clearly heard in Cincinnati by using by the tive Prest -O-Lite Co., Inc., from their factory and negative terminals are large ground connections only. enough Pittsburgh, at Speedway, Indianapolis. Ind. It will to allow easy ample gripping of Schenectady and connection clips. other high power stations are picked up regularly in the same manner. With "Kodel" Portable Like a Camera outside aerial, the set is claimed to have, under favorable condi- In the early day of the automobile, the tions, truthfully a range of from coast to car owner used to place his machine in coast. the garage long before the first snow fall, there to let it remain until the coming of Spring. It was thought that an automo- Big Production Increase Planned bile was of no use, and impracticable to by Pacent operate, during the Winter months. The Pacent Electric Company, Inc., of For some time the radio operator has 22 Park Place, New York, manufacturer held to an equally foolish view of Summer of the well known Pacent Radio Essen- receiving conditions. The use of radio tials, announces the opening of its en- during the Summer months was thought larged factory, laboratories and engineer- to be impracticable and impossible. ing department at 91 Seventh Avenue, be known as the Prest -O -Lite Super - Winter driving was not exactly a pleas- New York City. Service Radio "B" Battery and will be ure before, the windproof top and the The Popularity of Pacent Radio Essen- supplied in 24 and 48 -volt sizes in 4,500 closed body became standard equipment. tials reached a point last season where the and 2,500 M. A. H. capacities for each. Neither has the use of a radio set with old Pacent factory on 38th Street was It is designed not only to produce depend- its cumbersome storage battery, bulky unable to cope with the increase in pro- able continuous service but to harmonize size, and the need for a suspended aerial. duction that was necessary. The new in appearance with the finest furniture been much of a success as a portable factory is believed to provide for future and radio sets. proposition for Summer use. service that is more consistent with the It is generously proportioned and rug- All of these disadvantages have been quality of their products. gedly built to insure trouble -free opera - overcome in the design of a new and The Pacent Company lay great stress tion and uniform voltage without the novel receiving set that fits a neat leather upon the careful inspection and testing disturbances- causing reception faults fre- covered carrying case of practically the of their apparatus before it leaves the quently attributed to other sources. same size and general appearance of a factory. In their new factory the testing The cells are kept correctly spaced and camera. You can now take your radio department has been considerably en- are protected from breakage by spacing set with you wherever you go without the larged and improved in every way. For I anels at both top and bottom. The semi - incoveniences formerly attached to port- the use of this department a number of hard rubber cell covers lock securely able radio sets. unique testing instruments have been around the jars and plate lugs, preventing The "Kodel." as this new receiving set constructed. seepage. The inside of the case is coated is called, is entirely self contained. "A" In one corner of the factory there is a with an acid -proof preparation and as a and "B" batteries, head phones, vacuum model room. In this room may be found further precaution the cell jars rest on a tube, and a fifteen -foot aerial and ground practically every kind of radio apparatus thick shock -absorbing pad containing an wire are accommodated within the small ever designed. It is used by Mr. Pacent acid absorbing and neutralizing compound. case which measures only 5 3/4x4 112x8 and his engineers for their experimental It is claimed that the entire contents of inches over all, and weighs but 4/ work, and in this room are being devel- a. cell could be suddenly spilled into the pounds complete with all accessories. opened many new Pacent Essentials that case, yet all the acid solution would be The "Kodel" requires no loop or aerial will make their appearance during the absorbed and neutralized without the for its successful operation. A single con- coming season. slightest danger of its soaking through nection to water pipe or other ground is A completely equipped laboratory is and damaging the furniture. all that is required. Where a ground is maintained for the purpose of making Another feature of the design to which not available, stations from 50 to 100 special tools, jigs, etc., necessary to the particular attention has been given is the miles away can be heard with surprising manufacture of Pacent Essentials. This cell connectors. Great precautions have clearness by merely throwing the fifteen - laboratory functions in close co- operation been made against short circuiting. foot ground and aerial wires on the floor. with the drafting department.

Radio Age, Inc.. 500 North Dearborn Street Chicago THE WORLD'S Gentlemen: Please send me by return mail your illustrated Radio Agc Annual. containing more than 100 big pages of hookups and instructions and also send me Radio Age. The Magazine of the Hour. for one year. I enclose $3. This will give me a one dollar book and a $2.50 subscription at BEST BUY! a saving of fifty cents. Please start my subscription with the..._...... _.._...... _.._- ...... _...__ -__ number. Name Radio Age Annual, the best hookup book, and one year's subscription -$3. if you want this double bargain sign the City coupon and mail at once. Send price by check, currency or money order. If by State check add five cents for exchange. dip the coupon at the right. 11 book alone is desired. mark cross here O and enclose $1.00. If subscription only. mark cross- here p and enclose $2 O. A Manufacturera' International Exposition Under rM ur.stro.yJa r F. Aar 'A MAMMOTH SPECTACLE e, ç11t--ST- or SCIENTIFIC ACHIEVEMENT RADIO WWORLDS FAIR adson Square Gárdá SEPT. 22-0)28 MonI dp t.o d st Extraordinary Features Daily!: i :

A Manufacturers' Exposition WHICH WILL BE ATTENDED BY THE PRINCIPAL RADIO JOBBERS AND DEALERS OF THE UNIVERSE

De Luxe Exhibits By Nationally Known American Manufacturers

Representive Displays By The Famous Manufacturers Of

ENGLAND FRANCE "(V BELGIUM ITALY SWITZERLAND & AUSTRIA

Direction of U. J. Herrmann and James F. Kerr

Look for Business Office the RADIO AGE Prince George Hotel, Booth -No. 1 New York City. in Section L. Listen in 012 wr..w Better Still Crosley 50 $14.50 New Crosley Radio Receivers ROVING that Crosley Radio Receivers have made Satisfied Customers, The Crosley Radio Corporation sold more receiving sets last year than any other manufacturer in the world. The new line illustrated is still Crosley here better as shown Crosley 51 $18.50 by laboratory tests and by reports from users of performances under all weather conditions.

Listen in on a Crosley- compare it with other receivers -then you will choose a Crosley !

CROSLEY 50, a new one tube Armstrong Regenerative Receiver. We believe this to be the most efficient one tube receiver ever put on the market Price, $14.50 Crosley S0 -A, two tube amplifier may be added at 18.00 CROSLEY 51, two tube regenerative receiver, the biggest selling radio receiver in the world. Gives loud speaker volume on local and distant stations under average conditions Price, $18.50 Crosley 5I-A, one tube amplifier may be added at 14.00 CROSLEY 52, a new three tube Armstrong Regenerative Receiver. Provides loud speaker volume on distant stations under practically all conditions Price, $30.00 CROSLEY 51 -P, this is our new portable set. It is the Crosley Model SI. two tube receiver mounted in a leatherette covered carrying case, battery space and all self -contained Price, $25 .00 Croaky 51-P $25.00 CROSLEY TRIRDYN 3R3, this three tube receiver gives the efficiency and volume of five tubes. We believe it is the most efficient receiver on the market at any price for bringing in long distance stations Price, $65.00 CROSLEY TRIRDYN 3R3 SPECIAL, the same as the Trirdyn 3R3, except cabinet Is larger to contain "A" and "B" dry cell batteries and accessories. A beautiful set to match the highest grade of furniture Price, $75 .00

Crosley Trirdyn 3R3 $65.00 an.' below Trirdyn Special $75.00

MAIL THIS COUPON TODAY. The Crosley Radio Corporation, 863 Alfred Street, Cincinnati, O. Gentlemen. Please mail me free of charge your complete catalog of Crosley instruments and parts together with Better -Cost Less booklet entitled "The Simplicity of Radio." Name Radio Products Address

All Crosley Regenerative Receivers licensed under Armstrong U. S. Patent 1,113.199 THE CROSLEY RADIO CORPORATION 863 ALFRED STREET Powel Crosley, Jr., President CINCINNATI, OHIO The Crosley Radio Corporation owns and operates broadcasting station WLW