The KH-27 RECEIVER by Kenneth Harkness

TELEVISION ON LIGHT RAY! 15 Cents

Tubeless Amplifier Announced D10 Grid Biasing Through Resistors Reg. U. S. Pat Off. A Simple 4 -Valve Circuit

America's First and Only National Radio Weekly Hookup for Overseas 'Phone Set ol. 10 No. 19 Illustrated The KH-27 RECEIVER By Kenneth Harkness

FIG. 1-The wiring diagram of Kenneth Harkness' latest receiver, the KH-27. See article on page 3.

J.;

FIG. 2-Top view of the receiver after the wiring has been completed.

110W TO RID RECEIVERS OF PARASITIC NOISES 1,ANGMUIR'S GREAT LABORATORY ADVENTURE RADIO WORLD

WITH so much interference these days, why not improve your detector tube action and gain selectivity? Simply install a Bretwood Variable Grid Leak.Price $1.50.

.,.moo

The Bretwood Variable Grid Leak

NORTH AMERICAN BRETWOOD CO., 143 West 45th Street, N. Y. City. Enclosed find $1.50, for which send me one Bretwood THE Bretwood Variable Grid Leakmay Variable Grid Leak (or $2.00 for leak with grid condenser attached) on five-day money -back guarantee. be installed in any receiver ina few minutes.Single hole panel mount makes NAME this possible. Use a Bretwod andmarvel at STREET ADDRESS the difference! CITY and STATE (Inquiries Invited from the Trade) By ARTHUR H. LYNCH How to Build A Series of Five Important Articles on THE DIAMOND 5 -Tube Model HOW TO USE THE DE LUXE SYSTEM Herman Bernard, designer of this wondercir- mai, has written at, illustrated bookleton "How This seriestells how tobuildthe 2 -tube to Build RADIO WOILD'S Improved Diamond the Air." of De Luxe Receiver (without audio) and how to Send 50c and getthis booklet,including afull -sited wiring blueprint and free adopt this or any other set so as to obtain the name piece. necessary power from the AC electric lamp Outstanding Features of Set: (1) Fans, charmed socket. by tone quality, sensitivity and selectivity, port speaker reception of far -distant stationsre- Mr. Lynch is one of America's leading radio authors and designers.He has done with great volume. the best job of his life (2) A 2 -tube earphone set, in this comprehensively illustrated series, adigest of which a5 -tube speaker set, and aseparate 3 -stage follows: audio -amplifierforimmediate use Dec. 25 issue-Theoretical and historical discussion of the De Luxe Receiver and tuner, are combined in one. with any the audio channel and B eliminator. (3) No rheostats Jan. 1-The 2 -tube set fully described and illus- are used.(4) The setisinexpensive to con- trated,including wiring and choiceoftubes.Jan.8 --The National Lynch Power struct and maintain.(5) The set works from Amplifier and B Supply(3 -stage AF and B and C eliminator, adaptable to any outdoor aerial or loop; henceno aerial problems receiver).Many illustrations include picture diagram of wired connections to photo- present themselves, in city or oonistry. graphed parts.Jan. 15 and 22-Be Luxe reception from lamp socket with latest de- Send $6 for year's subscription and vices, including trickle chargers and A battery, relay, trickle charger and Alox filter, blueprint. get booklet, with picture diagrams of wiring, from antenna to the Acme speaker. [Newsdealer, or radio dealers, orderthe book- Send 15c for any one copy, or 60c for all five. lets with blueprints included, in quantity,direct Send $6 for one year's subscription (52 num- from American News Co.or braneheel bers) and get the five copies FREE! RADIO WORLD RADIO WORLD 145 WEST 45th ST. NEW YORK 145 West 45th St., NewYork City Ira X A Weekly Paper Published by Hen- No. 19 nessy Radio Publications Corporatiorw from Publication Office,145 W. 45th JANUARY 29, 1927 RAW:RM. PAT.'CiFF 0 Street, New York, N. Y. Whole No. 253 Phones BRYant $558 and 5559 15e Per Copy- $9.90 Per Year WORLD [Entered as senond.nlasamatter, March, 1923, at the poet office at New York, N. Y., under Actof March 3,18971 The Harkness KI-1027 Receiver A orc s Sensitivity, Simplicityand Pure Tone. By Kenneth Harkness Consulting Radio Engineer Designer of the famous Harkness Reflex and the Harkness Counterflex Circuits. IT isreally astonishing that after six years of broadcasting,afterthein- stallation of elaborate and costly radio receivers in thousands of homes, the vast majority of those who listenin nightly have actually no conception of how radio tttNNETWOINF,N should really sound. This statement may seem to be rather FIG. 3 a wholesale indictment of present day The front panel view of the receiver. The antenna circuit is tuned by the dial at radio receivers.Itisnot.Fortunately, left. The righthand dial controls two gauged condensers with one motion. The volume many sets are capable of faithfully re- control is the rheostat at center. producing voice and music. Nevertheless, thevast majority of set owners have never really heard the almost perfect re- in a natural, unstrained manner. This ef-and relative strength of the various par- production which modern methods of ra- fect of realism can be achieved with the tialtones which combine to form the dio transmission and reception have made proper equipment. sound. possible. They have no conception of the Similarly, most music can be reproduced amazing realism with which voice andwith the same realism. When the strains Accurate Reproduction music can be reproduced. of a violin issue from the loudsn-,ker, To achieverealisticreproductionof The set, particularly the audio amplifier,the sound should bring to your mind'smusical sounds, therefore, itis necessary is usually to blame. But even if the re-eye the figure of the musician and youaccurately to reproduce not only the fund- ceiverisgood, the loudspeaker oftenshould feel his very presence there inamental tone but all the overtones, with- causes distortion. And if the set and theyour home. A radio receiver should andout distorting any of the tones.If any speaker are both nearly perfect, the tubes, can be the medium through which actualof the tones are lost or distorted, the ef- the battery voltages or the battery elim-voice and music come to you throughfect of realism is destroyed. The repro- inators may be unsuitable. Few and far theether,carryingwith themeveryduction may be a fair imitation but it is between are the installations which har-shade of tone color which makes themnot an exact duplication of the original moniously combine to give true repro- distinctive, recognizable. sound mid the essential tone quality is duction. If the voices produced by your radio lost. It Is Up to the Listeners receiver are not the actual voices of the When John McCormack sings into the performers in the broadcasting studio, ifmicrophone his voice is distinguished by It seems a pity that such a small per- every note of music does not come to you itsquality, the warmth and color with centage of radio listeners enjoy the realwith all its tone shadings, as it would inwhich itis endowed. All the tones and benefits of radio. Most broadcasting sta-the concert hall, your receiver is failingovertones which combine to form this tions have modernized their equipmentyou as a medium of reception. There isquality are faithfully transmitted by the and have eliminated practically alldis- something wrong with your radio installa- broadcasting station. But if your receiver tortion from their transmissions. Famous tion.It may be the receiving set, it maydoes not embrace all of this, if it fails ac- artists are appearing before their micro- be the speaker, the tubes or the batteries.curatelytoreproduce each and every phones. The stations are supervising their The audio amplifier of your receiving settone, from the highest overtone to the programs carefully and are weeding out may alone be responsible. Whichever itlowest fundamental, you might justas the performers lacking real merit. They is, you are missing the true gift of radio,well be listening to an amateur singer arereplacingthem withthebest the thing which makes a radio receiverwhose performance is technically correct symphony orchestras,operaticstarsof more desirable than any phonograph- but without that quality which makes for the first magnitude, famous violinists and reality. greatness. pianists. The finest talent of the musical world is being offered freely. Reality Defined It is the purpose of this series of articles Unfortu- to describe a radio installation whichpre- nately, most radio listeners are not equip- Whatisreality?What makes oneserves and accurately reproduces all the ped fullyto avail themselves of these radio receiver sound better than another?tones and overtones of musical sounds, gifts of the air.Their receiving equip-How is the effect of reality obtained? To as mentdistortsthepure broadcast, and thereby creates the illu- transmissions answer these questions we must under- sionofreality.The receivingset,of of the broadcasting stations and theout- stand thenature ofsound. We mustcourse, is the most important part of this put of the average loudspeaker is justa realize that one musical sound isdis-installation and itsconstruction will be poor imitation of the original. tinguished from another not only by its described in detail. The best loudspeaker, Radio is no longer a mere "imitation"pitch and volume but by its tone qualitytubes and battery voltages touse with of voice and music. The days of howling,or tone color. It is this tone quality which this receiver will also be enumerated. squealing, distorting receptionare past.makes a note struck on a piano sound Itis now possible to possess receivingunlike the same note played on any other Set's Qualities Discussed equipment whichcan instrument. reproducevoice The pitch, or fundamental The receivingsetisknown asthe and music with almost perfectaccuracy frequency, is the same inall cases butKH-27 and was designed byme after and whichcancreate theillusionof thedifferenceintonequalitymakesmonths of experimentation, to reality. When the stationannouncer talks reproduce into the microphone, his voice, reproducedthem distinguishable from one another. musical sounds accurately andat the same by your receiving equipment, should This difference in tone quality can betime meet all the other standardrequire- absolutely natural. sound analyzed. Research has shown that mostments of a modern radio receiver.In musical sounds are actually composed of other words, the set has sufficientamplify- As If In Same Room numerous partial tones. The predominat-ing properties to make possiblethe satis- ing tone, by which we recognize the pitch, factory reception of broadcasting He should not sound as if hewere talk- is known as the fundamental; the otherswithin a wide radius; the stations ing through a megaphone,nor should he set is selective appear to be handicapped by the are overtones. The fundamental tone isenough to permit the receptionof a de- pres- the tone with the lowest frequency orsired station without experiencinginter- ence of a "hot potato in his mouth". Hepitch. The various overtones have muchference from other stations should actually soundas if he were inhigher frequencies. The on adjoining the same room withyou, talking to you qualityof anywavelengths; it can be operatedby any- musical sound depends upon the numberone, with ease, but above all,it employs 4 RADIO WORLD January 29, 1927 Neutralization Simplified 1.1yAuthor's Modification of Rice Method

LIST OF PARTS One KH-27 front panel, drilled and engraved, 7 x 26 inches. One KH-27 subpanel, 7 x 25 inches, completely drilled, with six stockets attached. One pairI.C. A. bakelite mounting brackets. One condenser 4 inch shaft, 9 inches long. Three KH-27 coils, T1, T2 and T3. Three KH Twinchoke Double Imped- ance Couplers. One KH output filter choke coil. Three Hammarlund17 -plateMidline FIG. 4 condensers. The wiring is done underneath the subpanel, for the most part. One Yaxley rheostat, 10 ohms. One Yaxley fixed resistance, 2 ohms. One Yaxley battery switch, midget. (Continued from page 3) not employed in this new system. Audio One Yaxley pilot light bracket. a system of audio amplification whichchoke coils, or impedances, are used in- One Yaxley Midget aerial switch. gives practically uniform amplication of stead, One Micamold grid condenser,.00025 all audio frequencies and which can ac- EachTwinchokedoubleimpedance mfd. commodate the comparatively large coupling unitconsistsof two identical One Micamold fixed condenser, .001 mfd. amount of power, or volume, necessarychoke coils, one acting as the plate im- Two Micamold fixedcondensers,.002 to obtain realistic reproduction withoutpedance and the other as the grid impe- mfd. distortion. dance. The two chokes are coupled by a One Micamold grid leak, 2 or 3 meg- The KH-27 receiver uses six tubes, two0.5 mfd. condenser connected from the ohms. as radio frequency amplifiers, one as de- end of one choke to the corresponding Two Tobe type 201 condensers, 1 mfd. tector and three as audio frequency am-end of the other. There is no magnetic each. plifiers. The electrical, circuit is given in coupling between the chokes, no trans- Two X -L Variodensers, type Gl. Fig. 1.Photographs of the set appear in former action.The two chokes and the Four Amperites (three Type IA and thisissue. The view of the front panelcoupling condenser are all enclosed in a one type 112). shows the operating controls.Stations metal case to form a complete unit with Two Kurz-Kasch Vernier Dials. are tuned in by means of the two vernier primary and secondary terminals.Each One set Eby binding postsforthe dials.The seconddialsimultaneously coupler is connected in the circuit in the KH-27. controls two condensers, joined by a com- same manner as a transformer, as shown - One 6 -volt lamp for pilot light. mon shaft.Volume isadjusted by the in the wiring diagram of Fig. 1, on front Four dozen 6/32 nuts and bolts, Y2 and rheostat in the. centre. This volume con- cover. 44 inches long. trol is not regenerative. That isto say, The advantages of this method of inter - S.oldering lugs and bus bar. you cannot make thesetoscillate by stage coupling are numerous. In the first varying therheostat.Each radiofre- place, the amplification of all audio fre- ACCESSORIES quency amplifyingstageiscompletely quencies, from 30to10,000cycles,is Four CeCo type A tubes; one CeCo neutralized.The system ofneutraliza- practically uniform. To fully realize what tion is an adaptation of the Rice method this means, compare it with the frequencytype H; one CeCo type J; three 45 -volt developed by me and is unusually effective range of the piano. The lowest note on Eveready B batteries; one 22% to 40%7 and easy to adjust. the piano has a pitch or frequency of 27.2 volt Eveready C battery; one 6 -volt stor- and the highest note a pitch of 4138.4 age A battery and charger; one Birnbach Uses Large Neutralizer cycles.Again, the pitch for the human nine -conductor battery cable; one West- singing voice is from 60 for a low bass to ern -Electric cone speaker; one Blandin The most unusual feature of the neu-about 1,300 for a high soprano. The pitch cabinet. tralizing system is the large capacity ofof the highest note ordinarily used in mu- he neutralizing condensers. The miximumsic is 4,138 but overtones with frequencies capacity of each condenser is.0001 mfd. up to 10,000 cycles enter into the compo- goes astepfarther.Itactually quad- This considerably simplifies the process of sition of musical sounds and speech. The ruples the power output of each tube. neutralization.Furthermore,unlikethe Twinchoke amplifier, then, covers the en- In other words, this amplifier can handle original Rice method, the rotors of the tire range of speech and m"sic and gives fourtimesas much power as atrans- tuning condensers can be directly con- uniform amplificationatallfrequencies former -coupledamplifier. Ifthe"over- nectedtoground,therebyeliminating which isthe prime requisite of an am- load" limit of a transformer -coupled am- body capacity effects. plifier. plifier (which, of course, can handle much The radio frequency transformers were Handles Much Power more power than standard resistance or designed especially for the KH-27.The impedance -coupled amplifiers)is reached primaries are large, insuring ample am- Furthermore, unlike some other audio by a given volume of output,it would plification and the prevention of sidebandamplifiers, the Twinchoke amplifier will take four times as much volume to reach distortion.Transformers T1 and T2 in-handle as much power or volume as the the overload limit of a Twinchoke am- clude the neutralizingcoils, which aretubes will permit without distorting sig- plifier, using the same tubes and battery placed inside the secondaries. nals in any way.The ordinary amplifier voltages.Sufficient power output can be A most important part of the KH-27 ishas a very definite volume limit whichobtained with ordinary receiving tubes the audio frequency amplifier, whichis cannot beexceededwithoutdistortion and B batteries to give reproduction which largely responsiblefor the remarkablybeing introduced.This limit is consider- other types of amplifiers can achieve only realistic reproduction of the receiver. Thisably lower than the "overload" limit ofby the use of extremely high voltages and amplifier employs a new, patented sys-the tubes.When the volume exceeds a higher power tubes. tem ofinter -stage coupling, known ascertain low value the leakage through This important and distinctive feature "Twinchoke" double impedance coupling. thehighresistancegridleaksisnot A three -stage Twinchoke audio amplifierrapid enoughtorelievethepotential of the Twinchoke amplifier can be easily was described by this writer in the Janu- charges impressed on the grids of the provedanddemonstratedinpractice. ary 1 and 8 issues of RADIO WORLD. To tubes.Rectifying distortionand "tube The explanation is based on the assump- make the present series of articles clear, blocking" results.The choke coil gridtion that grid currents may be produced however, itwill be necessary to reviewleaks of the Twinchoke amplifier com- without causing appreciable distortion as some of the facts already known to read- pletely eliminates this inherent weakness. thereisno magnetic coupling between ers of the previous articles. These grid chokes have a DC resistance the various stages of the amplifier.In a The Twinchoke system is the invention of less than 2,000 ohms and the coupling transformer coupled amplifier itisnec- of E. E. Hiler, who has been granted a condenser can discharge instantaneously. essary to adjust the potential of the grid basic patent covering the design of the Consequently, the grids cannot accumu- of each tube to prevent the generation necessary coupling units.The amplifier late excess charges, rectifying distortion ofgridcurrents.Otherwise,consider- is similar, in most respects, to the familiar and tube blocking are eliminated and the abledistortiontakesplace. "impedance -coupled" amplifier.However, amplifier can handle as much volumeas the high resistance grid leaks used in thethe tubes will permit. [Part II, the assembly and wiring, next standard impedance -coupled amplifierare Moreover,theTwinchokeamplifier week.] January 29, 1927 RADIO WORLD 5 Pick Up the Overseas'Phone With Set That DuplicatesCarrier By Capt. Peter V. O'Rourke A GREAT deal X-erreon-, of interest is displayedirithe reception of trans - Atlantictele- phony. The question of circuits offers an obstacle to many. If the telephony were car- ried on with or- dinaryradio,in whichbothside bands and the car- rierarepresent, FIG. 3 there would be no difficulty. All that The carrier frequency isa radio wave. would be required The voice frequency is an audio wave. The would be an or- result of mixing the two is a modulated dinary receiver in radio wave. The trans -oceanic telephone which the tuning system uses only the upper fringe of the circuitsaread- modulated wave,thinssuppressing the justed to the car- carrier and one side band. rier frequency of the signal to be received. This happens to be 5,- '000 meters or 60 kilocycles. B u t sinceonlyone side band without the carrier is used the problem is not quitesosimple. It is necessary to supply the missing carrier. The carrier may be re -supplied by oneofthe manyoscillating -circuits,provided that its frequency is adjusted to have exactly the FIG. 4 same value as the Circuit diagram of a receiver that will -originalfrequen- pick up the 5,000 meter transmission of cy, that is 60 kilo- the trans -oceanic system, supplying a fre- cycles.Forthis quency exactly equal to that of the sup- purpose an ,inter- pressed carrier. mediate frequency transformer may be used, provided above 60 kilocycles and these may be used, that its peak oc- provided they are not wound with too fine curs at a higher wire. A transformer may be wound which value than the 60 will perform satisfactorily. Starting with kilocycle frequen- a winding form 1.r/2 inch in diameter and cy.'tmust be the same length, the primary or plate coil higher so that a should contain about 500 turns of No. 34 condenser may be copper wire, perferably single cotton cov- connectedacross ered.It is not absolutely necessary, how- the secondary to ever, to hold strictly to this size of wire adjust thefre- and thisinsulation.Small variations in quency exactly. either direction may occur without great Of courseifthe change taking placeinthe inductance circuit will oscil- value of the coil. The secondary may be late at exactly 60 wound directly over the primary, with a kilocycles without few layers of paper between them, and the condenser this winding should have about the same then the conden- number of turns. ser is notre- A fairly large capacity should be used quired.But the (Herbert Photos) to tune thecoil, as this makes tuning accuracyofthe FIGS. 1 AND 2 easier and makes it possible to get on adjustmentmust the right frequency.Suppose that the be withinafew Top photo shows the control board at the Rugby, England, sta- capacityis1,000 mfd.(.001 mfd.) when cycles,otherwise tion, the European terminus of the trans -Atlantic radio tele- the frequency is 60 kilocycles. The in- the reproduced phone. This elaborate and conveniently arranged control board ductance of the coil should then be very speech will not be contains most of the mechanism for handling the overseas con- nearly 7 millihenries.This is just about -understandable, or versations. Bottom photo shows one of the twelve -foot antenna the value of the coil design given above. at least it will be spreaders used at the Rugby station for picking up the signals Since it was assumed that the conden- badly distorted. from America. ser has a capacity of 1,000 mfd. it may be The tuning, however, is not so very dif-one of the frequencies to any marked ex- obtained by using a variable condenser of -ificult,since the reception ison a hightent. There are many suitable coils whichthis rating.The distributed capacity of wavelength. may be used for this purpose that may bethe coil and the zero capacity of the cir- One receiver which may be usedis obtained in radio stores. cuit will add a little to give some leeway. shown in Fig. .4 Li and L. are the two The oscillating coil LsIo should be an But a 500 mmfd. condenser is more com- windings of an untuned intermediate fre-intermediatetransformerwithmuch mon.This may be used in connection quency transformer which has a peak at sharper characteristics so that it will cause with a fixed condenser in parallel, of about or near 60 kc, but this transformer must oscillations in the circuit and also hold the the same value. not have a sharp characteristic.Its pur-frequency after adjustment to the right The frequency may be obtained also pose is to pick up a frequency band from value. There are several transformers onby using a fixed condenser and adjusting 60 to 70 kilocycles without favoring any- the market which have peaks near or the secondary coil to resonance. 6 RADIO WORLD January 29, 1927 Use oflasing Resistors To Get Right Grid Voltages fromEliminators By J. E. Anderson mine the value of the resistance which will Consulting Engineer /80 v causeadrop of41/2 volts.By Ohm's law, 41/2 /.03 equals 150 ohms is the re- THE question of voltages in the output quired resistance. of a B eliminator offers difficulties to 90V A good way of providing both a 41/2 and some persons.They do not know how a 40 volt grid bias at the same time is to to select their resistors, how to measure 45V connect a 400 -ohm potentiometer in ser- the voltages on the various tubes, nor To filament ies with a 2000 -ohm rheostat, both of the how to adjust the circuit to get the proper o -tubes heavy duty type.The potentiometeris grid bias on the tubes. 45 V. connected first to the filament and then Those who have investigated the prop- the rheostatisconnected between the erties of B battery eliminators have no 40V potentiometer and the negative end of the doubt observed the fact that the output line.Then to get the proper grid bias voltages of thedevice depends on the on the last tube the rheostat is adjusted so. current which it is delivering.The volt- that the sum of the 400 ohms in the po- age as measured across the terminals of tentiometer and the resistance of the rheo- the instrument decreases as the current stat is 1,333 ohms. The 4% -volts bias for it delivers increases, and the rate at which the other amplifier tubes is obtained by it decreases is usually shown in a curve sliding the arm of the potentiometer until known asthe regulation curveofthe the voltage between the filament and the eliminator. A goodeliminatorshould arm is41/2volts.This adjustment does have a regulation curve which isvery not change the current flowing in the re- nearlyhorizontal,thatiswhich gives sistance and hence it has no effect on the nearly as high voltage output for large bias on the last tube.This however, as- currents as for small.But inallprac- sumes that there is not current flowing ins tical eliminators at the present time the any of the grid circuits.The assumption. decrease in the output voltageiscon- Current is justified, because when the bias is just siderable, so that if the regulation curve right and when the tubes are not over- of any particular device is not as straight loaded there is no grid current. andlevelastheidealthe instrumentable voltage we must get both plate and Milliammeter Very Convenient should not be condemned. grid voltages for the various tubes. How Need of Low Output Resistance can this be done? The choice of the resistance Rs and Rs Suppose that the last tube in the circuit isalsoa simple matter. The amplifier The reason for the variation of outputis a CX-301, which uses 180 volts on the tubes are to have a plate voltage of 901 voltage with current drain is the resistanceplate and with 40 negative volts on the volts.Now, the voltage between the fila- of the rectifying device and of the filter grid. ment and the high side of the line is 180 This tube may be taken care of by volts. coils.A good instrument should have a dividingtheavailable 220 volts in It is necessary to drop 90 volts to rectifier with a yery low output resistancethe ratio of 180 and 40 between the platebring the voltage on the amplifiers down and grid respectively.How can this be to 90 volts.To get the correct resistance be wound with heavy enough wire 'to done? value of 12, itis necessary to know how keep the total resistance low.In the ac- much current flows in this resistance.As companying drawing theresistanceR. Resistor In Common Lead afirst approximation this may be esti- represents the resistance of the eliminator mated by adding up the platecurrents, as measured atits output terminals.It As shown in Fig. 1, it may be done byin all the amplifier tubes which are served includes the resistance of the rectifier asconnecting the plate of the tube to theby the 90 volt tap.Suppose that there are well as that of the filter coils. high potential side of the eliminator out-three tubes and that each tube takes a. The output voltage of the eliminator isput and the low potentialsideofthecurrent of two milliamperes.The three the difference between the emf in the out-eliminator (B minus) to the grid return. tubes then take six milliamperes.Hence putcircuit oftheeliminatorandthe It then remains to connect the filament90/.006 or 15,000 ohms is the required value voltage drop in the resistance R0.That of the tube to a point which is 40 voltsfor R,.To adjust the voltage more ac- is,if the emf is equal to E, the output higher than the negative end. curately a milliameter should be inserted voltage V of the eliminator is given by One way of doing thisis to provide ain the 90 volt lead at the point marked_ where Iisthe curren flow- resistanceR. through which theplate X, and the reading should be used for the ing in the circuit, or is the total currentcurrent from all the tubes must flow be- current flowing through R.In the same required by the set.E is the maximum foreitcan return to the negative side.way the total current flowing in the out- voltage that can possibly be obtained fromThe amount of this resistance is determinedput of the eliminator may be measured by the eliminator and is the voltage across by the total current that flows through itinsertingamilliammeteratthepoint the output terminals when no current isand thedesired voltageacrossit.In marked Y.This reading should be used flowing.Itisa constant as far as thethis case the currentis30 milliamperes in determining the total value of R..It output side of the eliminator is concerned. (20 for the CX-371, 10 for the other tubes) was assumed that the current here is 30 It depends only on the type of rectifierand the voltage, let us say, 40 volts. Apply- milliamperes, but the actual current may and on the input to the device. ing Ohm's law gives1,333 ohms as thebe different from this. requiredresistance.Theresistorused Curve Helps Greatly should be variable within sufficiently wide Add the Separated Currents The resistance R. is not a constant butlimits to allow variation of the grid bias. It will be observed that the output volt- depends somewhat on the amount of cur-In this particular case the maximum re- age of the eliminator will depend on the rentthatthe eliminatordelivers.The sistance should be about 2,500 or 3,000values of the various resistances used in regulation curve obtained with a constant ohms. the eliminator.For this reason the cor- resistance is shown in Fig. 2, but the regu- In the above example it was assumedrect final adjustment cannot be obtained lation curve of an actual filter is crooked that theentire 30 milliamperesflowed unless the final currents are known. The and runs something like the lower curvethrough the entire part of the resistance. characteristics of the various tubes used in Fig. 2. This may not be the case always, and then should be known, as well as the voltage When a circuit is to be adjusted as toit will be necessary to modify the aboveregulation curve of the eliminator. From plate and grid voltages the first informa- results.Each section of the resistancethe curves pertaining to the tubes used, tion.necessary is the nature of the regula- should be treated separately by multi-the plate current for the desired plate tion curve of the eliminator to be used.plying the resistance of each by the cur-voltage and the desired grid bias should One must know the output voltage at allrent flowing in it.Then the total voltagebe looked up.And these currents should - current values likely to be met in the par- drop in may be obtained by adding tobe added together to get the total current. ticular circuit that is to be adjusted.For gether the partials. For example, it may be that these curves example, the receiver may require a total Obtaining Other Biases show that each of the three tubes assumed of20milliamperesafterithasbeen above will take a current of 5 milliamperes. properly adjusted as toplate and grid The resistance drop method of obtain-when the bias is 41/2 and the plate voltage voltages.,The regulation curve will then ing a negative bias may also be used foris 90 volts.The total current in the re- answer the question: What will be the the other amplifiers in the receiver.Sup- sistor R. would then be 15 milliamperes, output voltage at 30 milliamperes?Sup- pose the tubes used in the previous stagesinstead of 6 ma. The curve for the power pose that the curve shows that the outputrequire a grid bias of minus 41/2volts. tube may also show that the current in voltage is 220 volts when the total currentWe already know the total current flowing the plate of that tube will be 20 milliam- drain is 30 milliamperes. From this avail - in the resistance and it remains to deter-peres for the plate and grid voltages speci- January 29, 1927 RADIO WORLD 7 Tube Completes the Circuit At Otherwise Open Ends of the ItSupply (Concluded from page 6) "r Ty fled.So far, then, the total current will 0. 0. be 35 milliamperes. To this must be added 0c> the current in the detector plate, which 0 0 c00 may be one milliampere.Then the cur- 0 I a rent in the output of the eliminator will 0 0 be 36 milliampees.If the eliminator will 0 30: T00 give an output voltage of 220 volts when thecurrentdrainis 36ma.,all is well.The resistances may be calculated as illustrated above.But if the output voltage is less than 220 it will either be necessary to employ a lower plate voltage on the tube or elseitwill be necessary to increase the input voltage on the AC A R side of the eliminator.This may be done by decreasing the number of turns in the ." primary of the input transformer, where this is physically convenient. Ei R.,e }R+ Can't Use Ordinary Voltmeter =Mt The calculation of the resistance R. in MEM sss s. 1' the plate circuit of the detector is made CI in the same ways as the others. When the voltage from filament to the high side -of the line is180 volts and the voltage LZ required on the plate of the detector is FIG. 3. 45 volts, the voltage drop in R. is135 volts.The current in the plate of thetion with B eliminators may be under- duction but electronic convection through detector may, for example, be one milli-stood more easily when it is recalled that space.Since the entire filament contri- ampere.This would require that the re-the plate to filament space forms a con-butes electrons, the plate current isdi- sistance of 12. be 135,000 ohms. The trueductive path which offers a certain amount vided between the halves of the filament, plate current in the detector should beof resistance to the current flowing. When as shown by the arrows. obtained from the characteristic curvesthe filament is heated and when a posi- Division of the Current of the tube used as detector, or elseit tive voltage is applied to the plate the should be measured at the point markedelectrons emitted by the filament are at- One part passes down the negative leg Z when the resistance R. has approxi-tracted totheplate and they form aand the other down the positive and this mately the correct value. convection stream of electrons from fila- has to pass through the A battery before It should be pointed out that the volt-ment to the plate.This stream of elec-it can return to the negative side of the age cannot be measured accurately with trons constitutes an electric current (DC) filter.It will be noted that the current an ordinary voltmeter.It will not givefrom theplatetothefilament. Thiswhich flows through the A battery flows the correct values at all, and hence thecurrent encounters a certain amount ofagainst the normal filament current. One resistances cannot be adjusted by varying resistance in its passage from the plate would expect from thisfact that when them until the voltage reading is the de-to the filament due mostly to the repul-the plate current is appreciable that the If the voltmeter is to give sioneffectoftheelectrons upon each filament would be less brilliant when a sired value. other.The effective voltage applied to certain heating current flowsinthe A an approximately correctindicationof the plate at any time is the voltage drop battery.This agrees with experience, be- the plate voltage, its resistance must be across this internal resistance, not thecause when the plate current is turned very large in comparison with the resist-AC resistance, but the DC resistance. on the filament becomes less bright. ance across which it is placed.Such volt- When more than one tube are connected The method of obtaining a grid bias is -meters are expensive, and are not found to the same source of voltage each tubealso shown in Fig. 3.It is obtained from -in any but the most completely equipped willtakeacurrent, and thecurrentsthe resistorsR.. and R. (lower left).It laboratories. from allthe tubes used are joinedin will be observed that The current from Fig. 1 has been used for illustrationthe source sothatthecurrentin allthe tubes passes through these re- only and is not to be taken as the correctthe eliminator is the sum of all the sep- sistors.Hence, when calculating the re- way of getting the voltage on the various arateplatecurrents. Thefiltercoils ristance value of them the total current -tubes.This refers especially to the 90must be able to carryallthis currentsupplied by the filter must be used.Re- volttap. The other twofollowbest without heating or without causing ansistor R. is a potentiometer of about 400 practice provided that R. is used for the undue drop in the voltage. ohms and R. is a rheostat of about 2,000 detector alone. ohms.The two are connected in series. Separate the AF Resistors Use of a B Eliminator The grid bias for the first two tubes is One resistor should be used for each The operation of a receiver with a Bobtained by connecting the grid return audio frequency tube in the circuit, andeliminator may be explained with the aid leads to the sliding arm as shown. one may beusedforalltheradioof Fig. 3.Starting at P (lower left cor- The grid bias for the last tube is ob- frequency tubes.The reason for sepa-ner), the positive terminal of the outputtained by connecting the grid return of rating the audio frequency circuits is theof the rectifier, the current flows in thethat tube to the most negative point on difficulty of by-passing audio frequency direction of the arrows through the choke the filter, or to the point M. The amount currents and preventing coupling betweenvils L. and L,.At the point P, it divides of bias for the last tubeisvaried by the various tubes. In every case the com- and goes in three directions to the platesvarying the resistance of the rheostat RA. mon resistance between two or more audioof the three tubes in the illustrative cir- This connection assumes, of course, that frequency tubes should be reduced to a cuit. In the plate circuitsof thefirst the required grid bias on the last tube is minimum. This minimum is the resistance two tubesresistorsR. and R.(lower greater than thatforthe other tubes. of the rectifier and the filter.To makecenter) are placed.The object of theseThe grid bias obtained for any tube is this a low minimum the regulation of the is to drop the voltage of the output ofthe voltage drop between the point P. and eliminator should be good, thatis,thethe eliminator to a value suitable for the the point to which the grid return is con- curve showing output voltage against cur- platesof the tubes.To calculate the nected.Or itis the product of the current drain should not be too steep, butvalues of these resistors itis necessaryrent flowing through the resistors by the should remain nearly horizontal. to know the voltage E when all the tubes resistance between the point P. and the When separate resistors are used in allin the circuit are working normally, thepoint where the grid return is connected. -the plate circuits of the audio tubes, thevoltage desired on the plates of the tubesIn the case of the last tube the total re- value of resistance is determined the sameserved and also the current flowing in sistance is the sum of R, and R,.In ad- way as in the case of the detector.For each resistance.The last tube usuallyjusting the grid bias it is best to adjust example, when the plate and grid voltagerequires no resistance, as the voltage ofthat of the last tube first, as 'this is the is right the plate current may be 5 milli-thefilterisadjusted in the process ofmost important, and also because it causes amperes. manufacturing. a change in the necessary adjustment of The course of the platecurrentsis the others.After this adjustment has Circuit Through Space Charge shown by arrows throughout. From been otbained the bias for the other tubes The selection of resistors for the plateplate to filament the arrows are dotted tomay be obtained simply by turning the circuits and the grid bias drop in connec- show that the ,current is not ordinary con -potentiometer arm. 8 RADIO WORLD January 29, 1927 An IFliasyoto It uild !rot rot I 't ber How to Wind the Coils for Regenerative Set

CH Rs C AFri RFT2

..7-s: IE Ca Of O R2 3 a, R/ 8-1-P140R. 4,1 [0 B-r19/1P C 0 Bt - OE r f? -t- S2 ..9 B-C-/- C" Ore- FIG. 1 The circuit diagram of the four -tube set. Another receiver may be plugged into the audio amplifier. By Ludlow Greer No. 22 double cotton covered.About a the radio frequency coil, and is woundon quarter of an inch should beleftbe- a separate three-inch diameter tubing with AN easy tuning, distance getting, se-tween these two windings, all of which are number twenty-two double cotton cov- lective, voluminous and qualityre-in the same directions.Be sure to keep ered wire.Watch the beginning and end ceiverisdiagrammaticallyrepresentedtrace of the beginning of both windings, ofthe windings here,also.The final in Fig.1. It employs a stage of tuned,either by bringing the leads to binding coilto be wound isthe tickler, which neutralizedradiofrequencyamplifica- posts, clips or just in a flexible fashion consistsofthirty-fiveturns of number tion, capacitatively coupled to a regenera- to pieces of paper, with the proper mar1-twenty-six single silk covered wire, wound tive detector, these followed by two stages ings.The next coil to wind is the plateon a two and a half -inch diameter tubing of transformer coupled audio frequencycoil L3. This consists of forty turns, beingand placed on a rotor shaft so the tickler amplification. wound on a three-inch diameter tubingturns inside the secondary coil L4. After the signal has been amplified inwith No. 22 double cotton covered wire. Across the secondary winding 12 and a distortionless manner by the' radio fre- Tab That Goes to B Plus the grid winding LA, variable condensers quency tube, the energy isfed into the having a maximum capacity of .0005 mfd., regenerative the condenser C3, At the twentieth turn on this windingCl and C2 respectively, are shunted. The which has a fixed capacity of .0005 mfd. either scrape some insulation off and soldergrid condenser C4 is of the standard .00025 CN, the neutralizing variable condenser, on a piece of flexible wire, or during themfd. type, although, it was found when has a maximum capacity of .00015 mfd. winding process, bring a small loop out,experimenting that some tubes (hard type) The first coil to wind is the radio fre-when thisnumber ofturnshasbeen worked better with a .0001 mfd. fixed type. quency transformer. The primary Ll con-reached.There are still two more wind- The grid leak R5 should have a resistance sists of ten turns, while the secondaryings to make. One is the grid coil L4 and of 2 megohms at least. winding L2 consists of forty-seven turns.the other is the tickler L5.The grid coil Both these windings are placed on a single consistsof forty-seven turns,the same Use of Amperites three-inch diameter form.All wireis number as on the secondary winding of The filament temperature of the detect- or and two audio tubes is controlled by automatic filamentballasts,R2, R3 and When Is Shielding Necessary? R4. Thefilament temperatureofthe radio frequency amplifier tube is controlled Oftencomplaintsaremadeabout bottom, which are sometimes neglected,partially by an automatic control, R, and. "static," when thereis no _static atall. as well as all sides.The shield inside the partially by a rheostat Rl.The rheostat The first thing to do is to find out whethertop must be attached to the remainder oftakes care of volume control.Using the the disturbing noises originate within thethe shield by a good electrical connection,301A tubes in the radio, detector and first set, or from an outside source.The usual such as a piece of phone cord, with the audio stages, these ballasts are 1A Amper- method followedistodisconnect the tinsel covered cords soldered or screwed ites.The rheostat has a resistance of 10. aerial and to assume thatifthe noise fast.Every part of the shield must makeohms.R4 isa one-half ampere ballast continues, itisthe fault of the set orgood electrical contact with every otherresistor, such as the 112 Amperite and is. accessories.This is not always the case.part, and the shield is then either grounded used to control the filament temperature One of the radio frequency stages, or the or connected to the negative A batteryof a power tube, e. g., CX-371. detector, may be picking up the inter- lead. The filament circuit of the audio stages ference from an outsidesource, acoil It is a knowh fact that the shield intro- may be disconnected with the aid of S1 acting as a miniature antenna.To de-duces a loss into the set ifitis allowed so that you may listento the detector termine whether this is what is happening, to get into the field of the RF trans- output, via the single closed circuit jack vary the tuning controls of the set.If formers.It is well, therefore, so to place J1.When you wish to listen to the out- the volume with which the interferencethe coils that they will be kept at leastput from the last stage of audio, both. is received can be varied by manipulatingtwo inchesfromthenearestpartof switches S1 and S2 are closed. thesecontrols,itisan indicationthat shielding and preferably four inches from The C battery in the radio frequency shielding is needed. each other, if their axes are parallel andstage consists of a series of three one and The simplest complete shield that willthe angular placement of the Neutrodyneone-half voltflashlightbatteries, which prove effectivecan be made from tinis not employed. When a shield is builtgives you a total of four and one-half foil, copper foil or similar non-magnetic into a set at the beginninFr, it may be usedvolts.For best results, it will be neces- metal.It will be necessary, in most cases, as one of the A battery leads, as in the sarytoexperiment withthevoltages. to dismount the apparatus from the panel,Radiola III.This eliminates the use ofThe B voltage for the radio frequency though, at times, thin strips of shieldingone long lead and insures a well con- and first audio tubes, B+ Amp., should be material can be slippedinto place be- nected shield. sixty-seven and one-half volts.The B. tween the panel and variable condensers, Battery leads may besixfeet longvoltage for the detector, B.+ Det. tube,. etc.Great care must be taken to avoidwithout serving as miniature aerials and should be forty-five volts.The B volt- short-circuits between the shield and thetending to pick up unwanted signals andage for thefirst amplifier tube may be various parts used in the set, unless the interference.If over that length, they ninety volts.The B voltage for the last parts whichitislikelyto touchare are a frequent cause of trouble. Both amplifier tube should be one hundred and. grounded.Besidescoveringthepanel A and B batteries should be kept as near thirty-five.A four and one-half volt C with a shielding material, which may bethe set as practicable.If for any reasonbattery, C-, is used in the grid circuit of schellaced on, theentireinside of thethey must be placed a greater distancethe first audio tube. A nine volt C bat- cabinet must be lined with metal in theaway, they should, by all means, be by-tery, CC-, is used in the grid circuit of same manner. This includes both top and passed. the last audio tube. January 29, 1927 RADIO WORLD 9 C Placement a Science Correct Angle IF Squelching OscilL Lion By Herbert E. Hayden THE success or failure of a radio receiver often depends on the position of one tuning coil with respect to another. The farther the two coils are placed from each other the lessis both the capacity and the magnetic coupling between them. Also when the two coils are placed approximately at right angles the magnetic coupling is less than when the two coils areparallel.The capacity or electro- static coupling does not depencr to any great extent on the relative angular po- sitions of the coils, but this coupling has an effect on the effective right angle arrangement. It is always possible at one frequency to place the two coils so that the sum of the capacity and the magnetic coupling is zero.But this does not mean that a position can be found where the total coupling is zero.There is nearly always a residual coupling which is due to resistance common to the two coils.But when the coils have been placed so that the sum of the magnetic and the capacity coupling is zero the residual coupling is usuallyverysmall,and thereforethe minimum coupling between the two coils is also very small. Not Exactly Right Angles (Hayden) IF COILS are properly placedin respect to each other they may be put even The two coils are usually not quite at 4 -inches apart.However, it is safer to rely on a -6 -inch difference, if space permits. right angles when the coupling is zero, because the capacity coupling distorts the axislies.This holds for either of theoutput of an oscillator. to the first coil. symmetrical arrangement.Itis usually coils with respect to the other, so that in Connect the other to the grid circuit of an necessary to tilt one of the coils with re-reality it is necessary to line up two planes amplifier -detector circuit.Listen in with spect to the other, or to raise or lowerat right- angles to each other. a headset.Then arrange the two coils it.When first placing the coils the axes When this arrangement has been ef-until the signal that gets through is the of the two should be at right angles andfected the zero coupling position will be least.It will be found that the position the plane in which the axis of one liesfound by moving or tilting very slightlyis quite critical, particularly when the two and to which the axis of the other is per-one coil with respect to the other. coils are too close together.This adjust- pendicular should pass through the mid - ment is very important when building a .11e of the second coil.In other words, How to Make Test RF set which is to be squeal -proof on the the geometric centers of the two coils An experimental way of finding the lower waves.The adjustment should be should lie in one plane to which one axis position of zero coupling is as follows.made in every Neutrodyne, because with- is perpendicular and in which the otherConnect the antenna and ground, or theout it the circuit will not neutralize.

At the close of the year about 30 merchant vessels ofthiscountry were so U. S. Tkes Inventory equipped. A very large number of naval vessels are also equipped with this apparatus. On July 8 the Attorney General of the of Advi.ince In 1926 United States rendered a decision to the effect that the Secretary of Commerce uartz Plates for Constant Frequency, Trans -Ocean 'Phone,has no jurisdiction as to the wave length, with the exception of the band between SendingofPicturesAcrossAtlanticandReceiver 600 and 1,600 meters reserved for Gov- ernment stations, or the power used by Improvements Cited in Survey by Commerce Dept. commercial stations, including broadcasting stations. The DepartmentofCommercean-'London. This service will be used com- Increase in Stations 'flounced that the issue of December 31 ofmercially in the near future. ;the. monthly Radio Service Bulletin No. With the development of transmitting Since July the number of broadcasting 117 is now available, with a full list of all pictures by radio itis now practical tostations increased 155, making the total -the 671 broadcasting stations licensed uptransmit weather maps to vessels at sea. number licensed on December 31, 671. A to that date. The Bulletin also contains Considerable, progress was made in thelarge number of the stations in this class a summary of the chief events in the de- perfection of receiving sets. The single - increased their power and changed their -velopment of radio, "Peaks in the Waves dial receiver came into greater use forwavelengths during this period. of Wireless Progress," from 1827 whenreception of programs from broadcasting The joint resolution of Congress ap- Savary found that a steel needle could stations. proved December 8 requires the applicant magnetized by the discharge from a A committee representing the depart-for a radio -station license to waive any Leyden jar, down to 1926. The full textments of the United States Governmentright or any claims of right against the of the statement follows: directly concerned studied our radio prob- United States to any wave length .or to 1926.During this year directional orlems and prepared proposals for consid- the use of the ether in radio transmission .beam transmission developed to a pointeration by the International Radiotele-because of previous license touse the where it may now be considered as prac-graph Conference which is contemplated same or because of the use thereof. tical for commercial usage. being held in Washington during 1927. Radiotelephone was used for the first The use of quartz plates for maintain- time in directing the filming of a naval ,ing constant frequency or radio trans- Pictures Sent By Radio scene, off the coast of California, for a mitters advanced considerably during the Commercial pictoradiograna services are photoplay. -year. now in operation between New York and Radio Service Bulletin No.117 may New York and London 'Phone London and between San Francisco and be obtained from the Superintendent of Hawaii. Documents, GovernMent Printing Of - Successfulradiotelephoneexperiments The use of the radiocompass (direction ice, Washington, D. C., at 5 cents a 'were conducted between New York andfinder) on shipboard increased materially. copy. 10 RADIO WORLD January 29, 1927 Langmuir% Great Adventure C me When He Was Alone with Tubein 'Lab'

Emission Increased 10,000 Times with One Filament and Not with Another, and So Thoriated Tungsten Came Into Use

By Dr. Alfred N. Goldsmith costly delays, until the final outcome, beout into filament wire one-half a thou- it successful or otherwise.Smaller organ- Chief Broadcast Engineer, Radio Corporationof sandth of an inch in diameter. America. izations, obviously, cannot afford to stand Now, thorium has the peculiar property the gruelling tests of patience, with itswhen heated of pouring forth in a flood of T issaid that every bridge exists terrific cost, which is part and parcel ofelectricalparticlesorelectrons.Itis, I the mind of the civil engineer beforepioneer development. however, mechanically unsuited for fila- itisflung acrosstheriver. Likewise, A Different Field ment use by itself.It would melt too a skyscraper existsinthe mind ofits easily, for one thing.However, by plac- architect long before the -siteiscleared Now in no other portion of the field ofing the thorium in diffused form in the and the caissons are driven down to bed-radio are research and development sotungsten, a filament of better mechanical rock.Again,every great paintingorimportant as in the case of the vacuum and thermal properties is obtained, while statue is conceived in its ideal perfectiontube.Consider, for example, the workstill retaining the electronic proclivities of by the artist's fertile mind long before itof Dr. Irving Langmuir, known through-thorium. is realized in material form.And so itout the world for his scientific achieve- The thorium in the thoriated tungsten is with radio: an achievement in practi- ments.You are not likely to find Dr.filament forms a layer of really unimagin- cal form never comes untillong afterLangmuir. inhisSchenectady researchable thinness on the filament.This layer patient and inspiredscientistsandre-laboratory,placing vacuum tubesina or film is very quickly driven off but the searchengineers have dreamtof newreceivingset,noragainstudyingtheheat just as quickly boils out fresh tbor2 physical principles and methods, followedcharacteristics of tubes with an array ofium to the surface, there to form a fresh by tireless experimenting until, despite all meters.To others must go those practi-coating. And soit , goes.The action is discouragements, they have achieved thecal tasks-tasks far down the long linemuch like that of a sponge soaked with chosen goal of a newer and a better wayof research and development.It is morewater which, reaching the surface,, evap- ofaccomplishingthatwhichismost probable that you will find Dr. Langmuirorates by the heat of the sun, yet the needed in the progress of radio. studying a new piece of apparatus for in-sponge all the whileisbeing squeezed Now at least three conditions must bevestigating the, behavior of the invisiblejust enough to keep the surface constantly met in order that a suitable product shallelectron,the atom or theeven largermoistened with a fresh supply of water. reach the ultimate consumer. molecule, or again of films of oil floating First, there must be available the un-on the surface of water, or still again the The Great Scientific Adventure divided services of learned men, with longphysical behavior of elaborate chemical Thereis much thatthe present-day experience and marked capacity for re-compounds, or once more the nature ofvacuum tube owes to Dr. Langmuir, as search, thoroughly acquainted with thelightemitted by some glowing vapor.well as to other scientists and research en- problems,and withthedetermination,These and many other apparently aca-gineers who work in research laboratories knowledgeandinspirationtodevelopdemic subjects-academic today, practicaldevoted to vacuum tube development.It new things and methods. tomorrow-are most likely to call for thewas Dr. Langmuir, who, in the course of But even thegreatscientistscannotattention and interest of this great scien-his investigations of the so-called "Edi- make bricks without straw. They require tist.Yet in time these seemingly abstractson effect" in incandescent lamps, found elaborate facilities in the way of appara-studies become important features of yourthat as the vacuum was made higher and tusand assistants.so that the secondvacuum tubes or radiotrons, and providehigher, the available electronic emission point is the material, as the French wouldfor still better radio results. from the hotfilament became steadily say, quite as much as the personnel. Turning from the general to the specific,greater until finally, when a vacuum tube there is the dry -battery tube.The fila- The Production Problem was immersed in liquid air giving an ex- ment of this tube, as well as that of thetremely high vacuum, the emission was Thirdly, there is need for the co-ordina-leading storage battery tubes,isbased 10,000 times its original value.This was tionofallresearch and developmentalupon what might logically be termed anan astonishing result, but, when the ex- efforts with thoseof production whichelectric sponge. periments were repeated with another lot must follow for a successful consumma- Insteadofchemicallypuremetallicof filament wire, no such increase in emis- tion of the process.In this connection, betungsten, with its.high operating tempera-sion developed. An investigation of the it noted that so vast is the scope of mod-ture, relatively limited life, and high costtwo lots of wire revealed the fact that ernsciencethat no one man can, do ofoperation, therehas been producedthe second lot was chemically pure tungs- more than to polish one facet of the dia-thoriated tungstenin which tinyfrag-ten, while the first contained thorium. mond ofscientific knowledge.Left toments of the rare element thorium are So it was that the thoriated tungsten themselves, many qualified scientistsarescatteredthroughoutthetungsten filament came into being. Much remained might find their labors lost either throughwhile itis in powdered form and beforeto be done, however, in the way of de- needless and exasperating duplication ofit has been swaged and sintered and drawnveloping just the right proportions of in- efforts on the same problem, or through gredients, as well as a process for mak- the failure so to co-ordinate their activi- ing the delicatefilament.Also, out of ties so as to cover every portion of the A TEST PANEL thesediscoveries came, special pumping field,and toexploreevery nook and equipment, including the Langmuir mer- 'cranny of the unsolved problems. cury pump for producing the high vacua. It is just here that the great industrial As a further development ofthe high organizations come into their own in the vacua research, suitable so-called "getters" field of applied science.It is in this con- were evolved whereby_ to sweep out the nection that these great organizations can lastvestigesofgas remaining inthe render a real service to society.These vacuum tubes after the allotted time for huge organizations, because of the very pumping in quantity production. magnitude of their operations, can afford In conclusion,itisevident thatthe to provide elaborate facilities, can place really good vacuum tube has a pedigree problemsbeforeleadingscientists,can (Hayden) that extends back to the research labora- assign each task to the right man, can FANS with limited means do not have tory.It has been fathered by scientists co-ordinate efforts so that all parts of ato stop their experimental work just be-of note.Its infancy has been spent in given problem will be covered with thecause they cannot afford to buy panels forthe laboratory;itschildhood has been simultaneous and co-ordinated efforts ofmounting their instruments.A wooden passed in the testing laboratory, at the specialists. board will serve just about as well as the handsofnone -too -kindskeptics;its What isstill more significant,thesemore costly insulating paneling.If theyouth has been devoted to production in great industrial organizations can affordboard is too thick to take the instruments,the largest tube factories in the world; to continue year after year, despite dis-recesses may easily be chiseled in the wood and in its prime of life it renders service couragements,setbacksandlongand to make the instrumentsfit. that is a credit to its sponsors. I U January 1`,2 N.\ I) \ It Tubeless Receiver Claimed Professor, Using Bismuth and Copper Offer of $100,000 by Westing Is REporrcil, But Goldsmith Denies It and Deprecates- the Device and Professor. Claims

By Robert Bangs RECENTLY it was announced at Mer- cer University, Macon, Ga., that the Westinghouse Electric and Manufacturing Co. had offeredDr. Palmer H.Craig, head of the physics department of the university, $100,000 for a new device which is supposed to replace vacuum tubes as amplifiers and detectors. The device is called an "electro-magnetic detector and amplifier" and consists of a series of bismuth plates stacked in a pile and interlaced with copper wires.The bismuth plates are protected by a coating of sulphur because bismuth, a very brittle substance, is likely to crumble. Long Sought After Many attempts have been made by various investigators to make use in this manner of this property of bismuth and of similar properties of allied metals but so far there has been no claim of success, until Dr. Craig came along.The most common attempted applicationisto the rectification of AC for filament and plate voltage supply.Lack of efficiency and ofdependability havebeenthemain causes of failure.Another limitationis the supply of suitable metals in commercial quantity. One of the metals which displays similar properties is molybdenum.This has been used by scientists of the Bureau of Stand- ards for converting light energy from the (Underwood & Underwood) sun into electric energy. DR. PALMER H. CRAIG and the device that he 1.4 Y enables reception From Earth to Sun! without any tubes_ A certain amount of success has been He styled the device "an application ofthent with a coeerinq of sulphur.Accord- achieved and it seems possible that power bismuth platesasdetectors and ampli- ing to the inventor, the bismuth plates will may soon be derived directly from the sun fiers," which would be usedinplace ofgenerate the energy to operate the radio in this manner.Here, also, lack of effi-present batteries and vacuum tubes in aand serve as a detector and amplifier. ciency and of adequate supply of the metal radio. Describes Process are limitations.There is plenty of molyb- What He Found Out denum to be had in different parts of the The processisdescribedin the scien- world, but not all molybdenum is suitable In his research for hisPh. D. degree tist's thesis as follows: for the purpose.There seems to be anat the University of Cincinnati, Dr. Craig "'The authorisatpresentusingthis active component in the metal which isfound that the bismuth plates might be soadditive principle in an application of the responsible for the peculiar property, andused and the actual invention is described Hall effectto rectification of alternating it is now the aim of the scientists to isolatein part in his doctor's thesis. current, with a method similar to that de- this substance. The inventor today spoke of the device scribed by Descoudres. Apropos theoffer to Dr.Craig, Dr.as "a seriesof about tenthin bismuth "The additive principle used in this con- Alfred N. Goldsmith, of the Radio Cor-plates, piled one on the other, with wiresnection produces a Hall potential ofWt.' poration of America, denied that any suchrunning between them and finally on outera! volts in low fields with thin bismuth offer has been made for Dr. Craig's de-to the actual radio set." films, and thus givestheHalleffecta vice.Dr. Goldsmith, chief broadcast en- Because of the delicate nature of thepracticalimportanceasarectifier, gineer of the corporation, deprecates thebismuth plates, Dr. Craig has protected pecially in radio and similar applications." idea that the peculiar property ofbis- muth can be used for the purpose claimed by Dr. Craig. He Is Not Yet Thirty [iistimate 900000 Canadian Fans Dr. Craig emphasizes the point that the Itisestimated thatthere are abouteight months of 1923, when the t,,a1 was device will displace batteries as well as300,000 radio receiving sets in use in Can- 134,486. vacuum tubes in radio sets. ada, which would indicate that about 900,- Canadian manufacturersofradio ap- Dr. Craig, who is not yet 30, developed000 are enabled to listen to broadcast pro-paratus are said to effect a domestic con- the invention, upon which he immediatelygrams, assuming that on an average three.,sumption of their product of about ISM, - applied for a patent, for his thesis at thepersons are served by each set, according000 sets within the next few years. University of Cincinnati where he receivedto a report to the Department of Com- ItisfearedinCanada, however, that his degree of Doctor of Philosophy last merce from Ottawa. the popularity of radio will be affected ad- June. Between April 1 and November 30, 1926, versely unless arrangements can he made When asked to show the invention, Dr. the Radio Branch of the Department of to prevent interference caused by several Craig drew out a small block of substance MarineandFisheriesissued 146,186 stations broadcasting on the same wave resembling sulphur.It was an inch thick,licenses to owners of radio receiving sets.length.Eastern Canada now hasonly about three inches long and two inches Thistotalrepresentsanincreaseof four exclusive wavelengths and Western wide.Protruding from the top were tiny11,700 in comparison with the number of Canada only two.There are 48 broad- wires.It was encased except for the top.licenses issued during the corresponding casting stations in the Dominion_ 12 RADIO WORLD January 29, 1927 Weather's 11-iffect On Series Condenser Signals Found Small Aids Selectivity Pickard Discovers Barometic Pressure May Have Some Influence -Study of Solar Force Called Important in Field on Radio Science long periods they are highly related to By Greenleaf W. Pickard sunspots and other visible changes of the From a paper delivered at the Institute of Radio sun's surface.And as radio research has Engineers not yet become a pure science, we do One of the outstanding problems today not have such systematic records to study is the nature and cause of those atmos-as those gathered through the years by pheric changes which produce such di- astronmical and magnetic observatories. versifiedeffectsasweather,magnetic Several times in the past twenty years (Hayden) storms and disturbances of radio recep- Ihave attempted systematic measure- How the fixed condenser is connected tion. ments of reception from distant stations inseries with the antenna. The problem is meteorological.If this in the hope of finding some correlation earth had no atmosphere there could bewith other elements.With the advent of By Caesar Bianco no weather and on an airless planet therebroadcasting I began a more systematic could be no long distance radio communi-measurement of field intensities from dis- A small condenser in the antenna cir- cation. tant stations, at first(in 1922) by audi-cuit of a radio receiver is at times very The only known important force whichbility meter, and later (in 1923) by con- useful.When the low waves will not acts upon the atmosphere is the complextinuous photographic recording.I againcome in satisfactorilyitis often due to radiationand emission from thesun. begantonoticecoincidencesbetween thefactthatthe antennaisfoo long Changes in this force are caused in twomagnetic storms and depressed receptionand is unsuitable for these waves.This ways; first by the movements of the earthdespite the fact that the first years ofcondition is remedied by putting a con- with respect to the sun, and second by broadcasting fellin a happy period of denser of about .00025 mfd. in series with actual variations in solar radiation.If the minimum solar activity and a magnetical-the antenna as shown in the photograph. sun maintained a constant radiation we ly quiescent earth. It "shortens" the antenna and makes it should only have to consider the earth's more adaptable to the low waves and con- rotation on its axis, which gives us night Effect on Chicago Station sequently they will come in louder.Of and day, and its movement in an orbit I have made a preliminary analysis ofcourse, at the same time it makes it less around the sun, which by the changingreception from WBBM, Chicago, with re- suitable for the longer waves.The, con- angle of the solar rays gives us the sea-spect to meteorological elements and par-denser therefore should be placed in a sons.If these movements were the onlyticularly with respect to barometric gra-convenient position so that it can be in- factors involved, weather, terrestrial mag- dients. serted and removed as occasion demands, netism and radio reception would follow So far the result has been negative.as by switching. the calendar to a far greater extent thanThe field at Newton Centre, Mass., when The condenser has also another advan- our measurements indicate. solar and magnetic periods are removed,tage in that it improves the selectivity of does not seem to depend in any waythe set, particularly on the longer waves. Does Not Go by Rote upon the relation of the line joining New-The reason for this is that it loosens the ton and Chicago to the isobars of the coupling between the antenna circuit and But in the scheme of things as they are, thus reduces the effect of the antenna re- we find that weather does not go accord-weather map. ing to the calendar, nor does radio re- But there seems to be a slight rela-ristance on the tuning system. ception. The visual evidence of sunspots,tion, which I have not yet fully investi faculae and prominences tells us that thegated, between barometric activity and collectionof receiving points as would sun is periodically disturbed, and meas- reception.Apparently days with greatfairly represent the earth as a wholes I urements of the light and heat receivedfluctuations of air pressure tend also tohave found that a bad night for reception by the earth have shown that this variesbe days of low reception.The relationin Newton Centreisingeneral a bad here is probably indirect; thatis, baro-night anywhereintheUnitedStates. ingeneral correspondence with visiblemetric activity may be linked with solarAnd Ihave also found that European changes on the sun's disk. disturbances, which are in turn associ-reception of distant broadcasting stations Definite relations have been established ated with reception. agrees remarkably well with my measure- betweensolarchangesandweather, It which have already been usefully applied is perhaps unlikely that any high ments of WBBM, to weather forecasting. correlation between reception and weath- But the secrets of this universe yield er elements will be found. rather to observation than to pure specu- Less definite today is our knowledge of lation. When we have a sufficiency of the the short wave and corpuscular radiation Weather Is Local right kind of data we can frame stable from the sun, which cause ionization and Solar disturbances and magnetic explanations; until then we are groping electrical currents in the atmosphere and storms are world-wide events, whereasin the dark.The relation of earth and even chemical changes. weather is rather a local matter.Analy- sun is a dominant one to mankind, and Made Many Tests ses of weather elements over the wholethe study of radio transmission phenomena earth indicate that here are areas of posi-may well throw new light upon this little - Our only direct indices of these radia-tive correlation with sunspots and alsounderstood subject. tions are such things as disturbances ofareas of negative correlation. terrestrial magnetism, atmospheric elec- Although I have not yet collected and tricity and radio reception; although overanalyzed reception data from any suchBureau Is Testing Where Fading Begins Washington. Dr. Thomas Parkinson, of Bureau of Standards, is trying to find out at just Using Same Wave forChain what distance from a station fading begins tobenoticeabletotheear.Using a Bureau of Standards testcar, he is spend- Stations is HeldDifficulting hisevenings testing thesignals of WRC. Washington. at the recent meeting of the Institute of Fading can be detected with Use of the same wavelength by anum- Radio Engineers in New York. a meter at ber of stations for chain broadcasting is "Inotice," one mile from the station, Dr. Parkinson not practical at present, according to Dr. saysDr.Dellinger,"that says. He has not yet reached the point J. H. Dellinger, chief of the Radio Lab- those who have studied the problem havewhere fading is audible, but believes it is oratory of the Bureau of Standards. carefully avoided drawing conclusionsas between five and ten miles. Complaints that a number of stations to the practicability of operating chain linked together prevent the average lis-stations on a single frequency. Theirin- SPARE THE FLUX tener from getting anything but the pro- vestigations make it plain, however, that Be extremely sparing with theamount gram sent out on the chain have resulted the 'flutter' effect will be sufficientlyseri- of flux used and use just enough solder in demands that all such stations be re-ous to make reception definitely worse byto run in the joint and makea firm con- quired to operate on the same wave. Thethe average listener than under thesys- nection. Large gobs of solderare entirely subject was given considerable attentiontem where each station hasa differentunnecessary and are almost certain to frequency." lead you into trouble. 13 January 29, 1927 RADIO WORLD Polarity Test Double irransmission Easily Made G.' lied. FadingAntidote Example of WBZ-WBZA Cited by Horn,of Westinghouse, As Worthy of Imitation-Rigid Frequenciesand Station Distribution Complete "Radio HappinessCycle"

Pittsburgh. two stations and travel different paths. Enough stations, properly placed; fre-Thus at a store two things were accom- quencies fixed rigidly by means of quartz plished-heterodyning, or whistling, was crystalcontrol;simultaneous transmis-averted by keeping the two transmitters sion from two or more stations in regions at exactly the same rate of vibration, and where "fading" is noticeable, or where at- the "fading" effect was reduced to a mini- mospheric and physical conditions distort mum. signals. How System Is Worked This isthe formulae of C. W. Horn, superintendent of radio operations of the The problem of synchronizing these sta- Westinghouse Electric and Manufacturingtions called for designing apparatus to fix Company, for solving the major problems and control the two waves at a frequency confronting radio broadcasters today. of 900,000 cycles per second. The start- Horn, who has participated actively ining point was an oscillator of fairly low the development of broadcasting,isre- frequency, controlled by means of a tun- sponsible for the operation of KDKA, ating fork or Piezo (quartz) crystal. These Pittsburgh; KYW, Chicago; WBZ, reasonably slow vibrations were conduct- Springfield, Mass., and KFKX, Hastings, ed over a specially compensated land line Neb., all Westinghouse stations. from Springfield to Boston. At each station harmonics, or multiples of the funda- Cites WBZ-WBZA Case mental frequency of the oscillator, were Horn cites the synchronization of twoseparated and amplifiedforbroadcast transmitting stations, 100 miles apart, inmodulation. order to broadcast, the same program The use of short-wave telephony for simultaneously on exactly the same wave-continuous broadcasting across the ocean length, as one of the outstanding accom- was again very forcibly demonstrated last (Hayden) plishments of radio engineers in the past summer when KDKA for three days main- THE simple test tube, with two stiff year. tained a schedule of broadcasts which wire leads entering a salt solution con-. These stations, WBZ, Springfield, Mass.,were picked up in Australia by local sta- stitutes a polarity indicator, and WBZA, Boston, are kept absolutelytions and rebroadcast. Previously, through in step, without any deviation from theirthe international relay system of West- fixed wavelength of 333.1 meters. To the inghousestations,programshad been By Edgar Breese listener, the program apparently comestransmittedtoEngland, Australia and from only onetransmitter,thoughin South Africa, and in a few instances had A simple polarity indicator may be made reality the incoming waves originate from been retransmitted. as shown in the photograph.First obtain a small test tube and a cork or rubber stopper thatfitsintoit.Through this stopper force two pieces of stiff bus bar wire separated as far from each other as possible.These wiresshould be long Artists Names Suffer enough to extend almost to the bottom of the tube.It is important that they do ID) not touch each other at any time. Mutib LionyFans Into the test tube pour a small amount of saline solution, or fill the tube up with water to within a half inch from the stop- WBBM Performers' Mail Bears Strange "Monikers" and Sugges-per. Then put a pinch of common salt tion Is Made That '"Noms de Radio" Be Adopted, Like into the water. When the salt is dissolved the polarity indicatorisready for use. John Piano and Mary Sweetsinger Connect the line to be tested across the bus bar terminals which extend out of the Chicago, Ill. simple and impossible to misspell.For stopper.As currentflows through the Is it important that an air audience be instance, there might be Mary Sweet - tester, bubbles will arise from the vicinity able to recognize the name of a favorite singer, John Piano, Peter Violin or Ray- of the immersed terminals. There will be artist when it is announced over the airmond Tenor. More trouble would arise,twice as many bubbles from one as from or seen in print? however, when it came to James Piccolo theother.The greater number arises The question has arisen at WBBM asand Robert Basso Profundo. from the negative. to whether a popular radio artist should Simple names of theSmith,Brown, The action that takes place is the break- not have a "fool -proof" name whichit Jones class might offer a remedy. Anding up of the water in the test tube. The would be impossible to mispronounce orthen enter' the correspondents who spell two components are hydrogen and oxygen. to misspell. their own names Smythe, Browne andThere are twice as many hydrogen mole- Every day the "fan" mail to the station Jounes. cules as oxygen molecules in a molecule of carries scores of misspellings of the names water. Hence there will be twice as many of the staff performers. No two listen- bubbles riseat one terminal as at the ers seem to hear in the same way the"The Prisoner's Song" other. Hydrogen is electro-positive. names that are announced.There are that is,its molecules are attracted bya mistakesinspellingeasilyexplainable Pooh-Poohed by Convictnegatively charged body. Hence the hy- and there are mistakes in comprehension drogen molecules appear at the negative impossible to explain. Cincinnati. terminal. Initials cause the most trouble.Fred "The Prisoner's Song" isn't popular with L Jeske, "the baritone with thelovin' prisoners or prospective prisoners. RADIO CLUB IS GOAL voice" and Colonel Nut of the Nutty This fact developed at WLW, the Cros- OF HICKSVILLE FANS Club, is most often written of as Fredley station in Cincli-mati, when a man who Eljesky.Lester D. Mather, musical di-was leaving in a few hours to serve five Hicksville, 0. rector, becomes Lester Demather. Marian years in the penitentiary called the studio A special effort is being made toorgan- Carlisle, soprano, is usually Mary Anne, and asked that a number be played forize a local Radio Club.A number of and Eunice Hoeffer's name offers almost him. enthusiastic fans got together recently insurmountable difficulties to those who The studio director was all ready to in-and discussed its possibilities. would applaud her organ playing.Nate dulgeinalarge groan, because "The Everypersoninterestedin radio, Caldwell, chief announcer, has been ap-Prisoner's Song" was put on the pensionwhether owning a receiver or not,was propriately addressed as Callwell; at otherlist at WLW long ago, but the prisonerinvited to attend this meeting. times heisColder, Colwell, and Cold-elect surprised him by asking for "Roses The principalobject and purpose of water. of Picardy." the club will be to improve radio recep- As a solution for these difficulties itis So the organist played the selection andtion by eliminating interference caused suggested that labels or "noms de radio" the prisoner -to -be got what he wantedby defectiveelectrical wiring and elec- be selected. These would be suggestive, for the last time in five years. trical devices. 14 RADIO WORLD January 29, 1927 A FREE Questicoand An - 1 -1. ewer radio stage, a .0005 mfd. fixed condenser Department con-

ducted by RADIO WORLD is shunted.Be sure that this condenser is 0. K. A .00025 mfd. fixed condenser, adio Universityziy.t shunted by a 2 megohm grid leakis Address Radio vE.=University, RADIO WORLD, 145 West used in the grid circuit of the detector 45th St., New York City. tube.B plus 1 equals about forty-five volts.B plus 2 equals about sixty-seven When writing for information give your Radio University subscriptionnumber. arid one-half volts.B plus 3 equals from ninety to one hundred thirty-five volts. A filament switchisinserted inseries Tb 'f7er2cts* with the A positive lead.If ninety volts off set B are used on the amplifiers, then use a four and one-half volt C battery.If you use one hundred thirty-five volts B, then use a nine volt C battery. A six -volt A battery is used to supply the filament voltage.Be sure to follow the marked posts on the audio transformers for connections. Now as to the radio frequency coils.The 2??. 14a Fil. beginning ofthe primary of thefirst RFT goes to the antenna.The end goes Direct -to To 37.4- to the ground. The beginning of the pri- .:4.e.B oF Bat. mary of the second RFT goes to the plate of the RF tube, the end going to the P post on the AFT1. The beginning of the secondary winding of the first RFT goes to the rotary plates of the first variable to Ch condenser and to the G nost in AFT3. lecYcZs The end ofthiswinding goesto the stationary platepostofthis condenser and to the G post on the first socket. The beginning of the secondary winding goes to the rotary plate post of the second variablecondenser, and totheswitch post. The end of this winding goes to one terminal of the grid teak and condenser 7b _fizz t. TO 072 CZ. p OS t Qg combination and to the stationary plate postofthe- second variable condenser. part' of set To set and The parts for this set can be placed on An t. 63 -tact a baseboard, seventeen inches long, and six inches wide.A seven by eighteen FIG. 502 inch cabinet with panel should be used. How to hook up switches for filament battery and antenna -ground control. Thedialsforthevariablecondensers should be placedatthe endsof the MY DAD presented me with a 5 -tubetransformers. These containforty-fourpanel, with the two rheostats in between. receiver, A and B batteries, and a chargerturnsand wound onthree-inchdia- The single circuit jack at the output, can as well.The A battery is of the storagemetertubings,usingNo.twenty-two be placed in the right hand corner, while type, white the B batteries are dry.Now, double cotton covered wire. On each ofthe filament switch is placed in the left in this set, rheostats are used to controlthese tubings is a primary winding, whichhand corner.The coils can be placed on thefilaments, there being no provision consists of ten turns.If you live veryinch cabinet with panel should be used made to shutoffthefilamentsupply, close to a station, space the primary aboutone at right angles to the other, with other than with the rheostats.I have a one -quarterinchfromthesecondarythe circumference of one coil exactly in double throw, double pole; a double throw,winding, or decrease the number of turns line with the center of thehorizontal singlepole and a single throw, singleon the primary winding to six.Should portionof the other coil.These coils pole switch.Please give a layout showingyou not desire to wind your own coils, you should not, however, be very close to the how to use these switches, for cutting incan purchase any standard tuned radioend plates, about a four -inch space being and out the filament supply, the chargerfreqency transformers, which have second-allowed.This can be worked out with and the antenna -ground, this being con-aries large enough to be shunted by thethe aid of one -quarter inch hard rubber nected so that the antenna goes to set variablecondensersyoupossess. Be bushings, which should be bolted to the or to ground.-Franklyn Morris, Atlanticsure of this fact, because, if there are tooscrews on the plate.The three audio City, N. J. few turns, you will get only the low wavetransformers can be placed in a row, about Fig. 502 shows the layout using thesestations and if there are too many the2 inches from each.The binding post switches.A piece of Bakelite or hardhigh wave stations will be favored.The stripis placed toward the rear of the rubber four inches wide and six inchesfilaments of the radio frequency and de-baseboard. The C batteries can be placed high is required.The double pole switchtector tubes are each controlled by rheo- in the cabinet, close to the audio trans- isplaced toward the left following the stats,having, a resistance offifteento formers. Use flexible wire to wire up the connectionsindicated. Theantennatwenty ohms, and having resistance wireset, being very careful to keep the plate switch is shown at the bottom, with thecapable of passing one -quarter amperes.leads away from the grid leads. proper connections. The filament cut outIn the audio portionofthecircuit,a *** switch is shown to the right.It will besingle ballast resistor is used in the fila- I HAVE afive -tubereceiver,using noted that you now have two filamentment circuit.This should be a 112 Am-two stages of tuned radio frequency am- cut outs, that is,the double throw andperite.Across the secondary winding ofplification,anon -regenerativedetector single throw. The double pole switch canthe audio frequency transformer in theand two stages of transformer coupled be thrown to the "on" position alt the time, except when charging, using the single switch for cutting the filament sup- O ply in or out; or the single switch can be left out, using the double switch for filament control. a *** I HAVE been given a pair of .00035 mfd. ct straight line frequency variable condensers; four -01A type tubes and three, four - R4 to -one ratio audio frequency transform- Rt. ers.Please give me a circuit design for the use of these parts, stating any other data that may be necessary to build the set.-Charles Mullone, Jersey City, N. J. Such a circuit is shown in Fig. 503.It is a reflex receiver, using a radio frequency amplifier, which also acts as an audio frequency amplifier;a non -regenerative detector and two stages of straight audio frequency amplification.The transformers are used in the reflex and audio stages. The variable condensers are used to tune FIG. 503 the secondaries of the radio frequency The circuit diagram of a four -tube reflex, desired by Mr. Mulfone. 15 January 29, 1927 RADIO WORLD should be employed? (4)-Can a rheostat be used to control the filament of the radio frequency tube ?-Lincoln Digmar, Clason Point, N. Y. (1)-Yes.(2)-Ten ontheprimary, forty-four on the secondary, wound on a three inch diameter tubing, using No. twenty-two double cotton covered wire. (3)-Use .0005 mfd. variable type.(4)- Yes, a twenty ohm type. The filaments of the audio tubes should be controlled by a ballast resistor of the one-half ampere type. * * * COULD THE parts for the receiver FIG. 505 diagrammedintheRadioUniversity columns of the Sept. 25 issue of RadioThe circuit diagram of the receiver with World, be placed on a baseboardsix the, special selector circuit. FIG. 504 inches wide and twenty inches long, and The circuit design for hooking up fila-then in a cabinet seven inches high andsary to shield this set?(6)-About how ments as requested by Sidney Greenstein.twenty-one inches wide, the panel beinglong should the antenna be?-Wallace the same size as the cabinet? (2)-How Gordon, Port Jervis, N. Y. audio frequency amplification.The 301A should I connect up a C battery in the (1)-Yes. (2)-Just disconnect the po- type of tubes are used throughout.At audio circuits of the first two tubes?-tentiometer, allowing the base of the crys- the present time I am using a rheostatHerman Manger, Atlantic City, N. J. tal to run to the P post of the audio trans- inthe filament circuitof the two RF (1)-Yes.(2)-Break the return leadformer and the rotary plates of the vari- tubes, one in the filament circuit of theof R5 and R7, which is now connected toable condenser to the B post on this detector tube and onetocontrol thethe minus A. Run this to the minus posttransformer. (3)-Yes. Be sure that the filaments of the audio tubes. Now I wishof the C battery. The positive post offilaments of both tubes draw the same to rebuild my set, and use a single rheo-this battery is brought to the minus Aamount of current and voltage. (4)-Yes. post. (5)-No.(6)-About 100 feet including stat.The control on the RF and detector *** tubes is not critical.This applies to the *** the leadin. control of the AF tubes also.Therefore, I AM going to build the neutrodyne set, I HAVE bin' t the three -tube reflex re- could I place the filaments of the RF andshown diagrainmatically in the June 26 ceiver described in the Radio University detector tubes on a single rheostat, whileissue of Radio World on page 11.(1)- columns oftl eOct. 9 issue of Radio the filaments of the AF tubes are con-Would itbe advisable to use a doubleWorld. The results are great,. but I would nected to an Amperite?Ifso,please condenser in the first two radio frequencylike to get the signals a bit louder, Could show the diagram, illustrating this meth- stages?(2)-If not, could three.00035 I hook up another stage of transformer od, showing how to connect up a fila- mfd.variablecondensers,usingradio coupled audio? Are there any special pre- Greenstein, transformers having fifteen turn primariescautions that should be taken?-Otis Mel- mentswitch,also.-Sidney and sixty-two secondaries, each wound onvin. City Island, N. Y. Bx., N. Y. City. three inchdiametertubings, with No. Yes, you can add another stage. The Fig. 504 illustrates this system of wir-twenty-four double cotton covered wire,plate of the present last audio tube goes ing.A 10 -ohm rheostat is used in thethe secondaries of the second and thirdto the P post on the new transformer. RF-detector filament circuit.Instead of coils being tapped at the twenty-first turnThe B post on this transformer is not connecting thefilamentsof the audiofrom the beginning be used?(3)-Is isbrought to the B plus post. Instead, it is tubes to a single Amperite, one is usedall right to use .00004 mfd. midget variablebrought to a new B plus post. The G post in each leg.The purpose of thisis to condensers?(4)-Could a double circuiton the transformer is brought to G post allow the use of a power tube in the lastjack be connected in the detector circuit on the new socket. The F post on this stage.That is, you can insert an Am-output?How? -'Willard Fordson, Westtransformer is brought to the minus post perite to pass the current the filament of New York, N. J. of a C battery. The plate of the last tube this tube draws.The arrow and dot in (1)-No. (2)-Yes. (3)-Yes. (4)-Yes.is brought to the top spring of a single series with the A plus lead indicates the The top terminal or spring is brought tocircuit jack. The bottom terminal of this filament switch. the plate post of the detector socket. Thejack is brought to another new B plus *** second spring from the top is brought topost. About ninety volts should be applied AT THE present time, I am using athe P post on the first audio transformer.to the plate of the first audio tube, and single circuit tuner, as per enclosed dia- The third spring from the top is broughtabout one hundred thirty-five volts to the gram and am troubled with interference. to the B post on this audio transformer.plate of the last tube. Use a nine volt C Ll consists of fifty turns tapped at theThe bottomterminalonthejackis battery inthe grid circuit of the last tenth turn from the beginning. Clisa brought to the B plus 2 post. This is the stage.Use a four and one-half volt C .0005 mfd. variable condenser,. while L2 detector B voltage. battery in the grid circuit of thefirst consists of thirty turns of No. twenty-six *** audiotube.The filamentof this new single silk covered wire. The antenna coil REFERRING TO thefour -tubere-tube should be controlled by a ballast re- is wound on a three inch diameter tubing,ceiver shown inthe Radio Universitysister, passing one -quarter ampere. The while the tickler coil is wound on a twocolumns of the Dec. 26 issue of RadioF plus post on this socket is brought to and three-quarters inch diameter tubing. World.(1)-I do not wish to use thethe F plus post of the other socket. Be Please show how to increase the selecti- crystal and battery as shown. Can a piecesure to follow this connection. Otherwise vity value of the set.-Harry Wright, N.of galena be substituted? (2)-How? (3)-you will have no means of cutting off the Y. City. Can the filament of the first two audiofilament supply, since you will note, the Fig. 505 shows how to make this settubes be controlled by a single ballast? filament switch is inserted in the positive more selective by the addition of an ab-(4)-Can I leave the double circuit jack atlead of the A battery. sorption coil in the grid circuit.A ten - the detector output out?(5) Is it neces- (Concluded on page' 31) turn coil is inserted in series with the grid lead.This winding is made on a three- inch tubing, using No. twenty-two double cotton covered wire. A one -quarter inchJoin RADIO WORL 'S University Club spaceisleft and forty-fourturnsare wound.Acrossthislatterwinding,a And Get Free Question and Answer Service for the Coming 52 Weeks .0005 mfd. variable condenser is shunted. This Service for Yearly Subscribers Only By pushing the primary further away from the secondary winding, youwill Have your name entered on our subscription and University lists by special number. gain more' selectivity. Put this number on the outside of the forwarding envelope (not the enclosed return * ** envelope) an dalso put at the head of your queries.If already a subscriber, send $S REFERRING TO the circuit diagram for renewal from close of present subscription and your name will be entered in Radio of the three -tube receiver shown on page University. No other premium given with this offer. 15 of the May 15 issue of Radio World. [In sending in your queries to the University Department please paragraph them so that (1)-Could I use a three -circuit tuner in the reply can be written under or alongside of each query,Write on one side of sheet the radio frequency circuit, instead of theway. Always give your university number.] radiofrequencytransformerandthe variometer. The primary of this coil con- RADIO WORLD, 145 West 45th Street, New York City. sistsof ten turns, while the secondary Enclosed find $6.00 for RADIO WORLD for one year (52 nos.) and also enter my consists of forty-four turns. This is wound name on the list of members of RADIO WORLD'S University Club, which gives me onathreeinchtubing,usingNo. free information in your Radio University Department for 52 ensuing weeks, and send twenty-two double cotton covered wire. me my number indicating membership. The tickler consists of thirty-six turns of No. twenty-six single silk covered wire, Name wound on a two and three-quarter inch diameter tubing.(2)-How many turns Street should the radio frequency coil L3L4 contain,(3)-What size variable condensers City and State 16 RADIO WORLD January 29, 1927 MOVING PICITR[iSAN SOUND TRA

(Wide World) JOHN L. BAIRD, the Scotch inventor of a television system, listens in to the characteristic noise thateac picture makes during the transmission. At the time the photograph was taken hewas transmitting the face of a ventriloquist's dummy.

cut out both ultra -violet and visible rays anircl Uses InfraoRed and let through infra -red. The reason that Baird experimented with infra -red instead of ultra -violetis that infra -red is not as injurious to. per- In 1-lis Television Tests sons exposed to these rays.Ultra- violet rays burn the skin, cause headaches, injure the eyes, and produce other highly Unseen LightIsCarrier Wave inLondon Experiments- detrimental physiological changes. Infra -red light has none of these unde- Modulation of Voice on Ultra -Violet Accomplished by sirable characteristics, but both have the Massachusetts Institute Professor common property of being invisible to the human eye. Pictures or scenes transmitted by means By Knollys Satter -white dinary light.The photo -electric cell re-of infra -red light are slightly distorted sponds to both kinds.It is only neces-because of the varying reflecting power TELEVISION is making rapid strides. sary to illuminate the scene to be trans- of surfaces.For example, a certain sur- E. F. W. Alexanderson is not the mitted with the invisible rays and let face may reflect blue light and not infra- the electric eye see the scene. The meth-red. only one actively engaged on the subject. od of producing infra-red.light is to filter Such a surface would appear black Over in London a young Scotchman, John it out of ordinary light. in the reproduced picture. Only those L. Baird, is holding up Great Britain's surfaceswhichreflectinfra -redrays end.Just as Alexanderson has his re- For example, an incandescent lampwould appear bright in the reproduced volving drum, so Baird has his televisor. contains rays of all colors.A lamp that picture. Just what the details of the televisor are just barely glows with a red light emits What is the object of sending pictures has not been made known, but the term infra -red rays as well as the red that is by invisible rays at all?One object is to is as closely associated with the name of visible.It does not, however, emit any get a more intense illumination on the pic- othercolorsnorultra -violet. As the ture Baird as the plaid coat he wears as a temperature of the incandescent body in- tobe seat without havingitso symbol of his nationality and for good creases bright that the eyes would be injured. luck. other colors begintoappear.Another object is to enable one to take One thing that is in common with the When the light is of a white or bluishpictures in the dark without having any- nature_ there are present a great deal ofone know of it. systems of Alexanderson and Bairdis ultra -violet as well as the visible and the For example, it might the inevitable photo -electric cell, that me- infra -red. be necessary to locate a warship or an chanical eye 'that sees in darkness as well Ifit airplane at night. At present this is done as in the light.The latest accomplish- is only desired to use a certain by means of searchlight of visible light. ment of Baird is to send moving pictures color it is possible to employ filter whichThe ship or airplane can follow the beans by means of infra -red rays instead of or- will reject all colors.Thus, a window just as well as those who direct the beam, of ordinary glass will cut out i all the hence dinary visible rays of light. ultra -violet while a solution of a certain thedetectionoftheir presence There is no greater difficulty in sending color will would become known as quickly to those by means of infra -red light than with or- eut out most colors except detected as to those on the other side. that color.It is comparati'ely simple to If a beam of infra -red light is projected January 29, 1927 RADIO WORLD 17 'SMITT ON INVISILIE LIGHT RAYS his beam could not be followed as easily asthe visible.But those who control the infra -red beam could easily follow it vitha photo -electriccell,which would mmediatelydetectanylightreflected rom the object sought.Of course, the iefense against such a procedure would we to paint the plane or ship with a com- ,osition which would not reflect any of he infra -red radiation.It would remain .erfectly black to the photo -electric cell. Sound on Ultra -Violet Notonlycanpicturesand moving cenes be transmitted through space by leans of light and by invisible radiation, ut sound may be transmitted as well. 'his was recently demonstrated by Prof. tockberger of the Department of Physics f Massachusetts Institute of Technology. Dr. Stockberger employed ultra -violet Idiation in his experiments, although vi- ible radiation may be used in the same 'ay.In one of his experiments he pro- tctedmotionpicturesbyultra -violet ght, and this was the first time that its has ever been done.The pictures -ere projected with a standard projector ut all visible light had been filtered out om the light source before it went into .e projecting machine.The result was .at the projected picture on the screen 'as not visible.However, when a special reen is used, one coated with a flour - cent substance, the pictures were visible. le effect is a ghostly greenish -blue glow milar to that which is familiar to users X-ray machines. Wide World) Another experiment demonstrated by r.Stockberger was to send sound by PROF. DONALD C. Stockberger, of the Department of Physics of the Massachu- tra-violet light.The intensity of the setts Institute of Technology, with his violet ray receiving set, receiving broadcast ?ht beam was modulated in somewhat sounds and motion pictures on invisible beams of light.The pictures become visible e same way that a high frequency radio only when thrown upon a flourescent screen. ave is modulated.The modulated light am isthen picked up with a photo- ectric cell and the output amplified by ordinary amplifier and put on a loud All Radio Waves Have beaker. Directional Effect Colors, Expert Contends One peculiar effect of sound transinis- Indianapolis. audible frequencies and pass them out, as Dn by ultra -violet light is that the beam Discussing "Radio Waves and Reedy- electro-magnetic waves, or impulses which n be directed in very definite channels. ing Sets," over WFBM, Andrew J. Allen, actuate the headphones or loudspeaker. he light may be reflected, refracted, fo- secretary of the Indianapolis Broadcast "The theoryisbecoming more pro - sed by lenses of suitable material and Listeners Association, said: nounced that the radio wave or energy on.The beam travels in straight lines "Tuning a radio set is simply a process impulse is a form of color or light wave ore closely than ordinary visible light of placing the secondary circuit of the of very high frequency too rapid for the :cause of the shorter wave lengths of the tuning coil in resonance or in tune with eye todetector mechanical geniusto Ara -visible. One spectaculareffect,if the frequency of the wave that is desired. measure, but which can be converted into fls term may be applied A receiving set has three distinctive cir- lower frequencies that in magnetic form to anything that cuits-(1) radio frequency circuit to inter- are audible to the human ear. The feeble smnot be seen but only heard, is that the cept and amplify the high and inaudible F.ind transmittedmay becompletely energy of a radio wave as it strikes the upped by interposing the hand, or any electro-motive frequencies of the radio antenna or loop is measured in terms of ,Lier body opaque to the short waves, be- wave impulses;(2)detectorcircuitto one -millionth of a fly power. The radio reen the transmitter and the receiving rectify these impulses and convert them wave travels with the speed of light at coto-electric cell. to audible frequencies; (3) the audio am- the rate of 186,300 miles per second." Still another remarkable demonstration plifying circuit to step up or amplify the Allen received much fan mail. 1,Dr. Stockberger isthe use of ultra- -olet light to make objects visible in the crk.Thus, if a fence or an automobile Long Deaf, Manears Music 1 painted with a phosphorescent sub- since,these objects begin to glow as Radio has probably meant as much to "A new world of song, music and speech, :on asthe beam of ultra -violetlight the deaf as to any other class of persons. has recently been opened up to me, by :Tikes them. While invalids,shut-ins, and the blind the use of the radio, that has lain dor- This may be used, as Dr. Stockberger have testified concerning the joys it has mant for twenty years, as far as my abil- Iggested, to make automobile travel in brought them, to the deaf it has opened ity to hear is concerned, in any church, edark safer.Instead of equipping the up a field of enjoyment which it was ab- theatre, or public place, even from front ; tomobiles with glaringheadlightsto solutely impossible for them to obtain in row seats. Bearing that fact in mind you lind other car operators, the cars might any other way. Many persons who have will be better able to appreciate my feel- I: equipped with a source of ultra -violet been unable to hear for years, have dis- ings of joy and thankfulness, when I tell /;ht.This would not be visible to the covered that with a modern radio set and you thatIrecently installed a modern aerators yetit would make other cars the use of headphones, they can againen- radio, and with the headphones strapped d fences visible whenever the invisible joy music, speeches, and other forms of to my earsI have been able to hear 1 ht beam struck them, provided that broadcasts. clearly and distinctly the human voice in fese objects had been painted with a One case of this kind which was called speech and song, and all kinds of instru- posphorescent paint which would glow to the attention of WCCO, St. Paul -Min- mental music as clear and distinct as in .1 exposure to ultra -violet radiation. neapolis, Minn., was that of E. J. Goward, the days of my normal hearing, twenty merchant at Aitkin, Minnesota. He wrote: years ago." RADIO WORLD January 29, .1927 Committees Chosen THE RADIO TRADE For Mid -West Meet Des Moines, Ia. E. T. Collins was recently chosen general chairman of the' committee on arrangements for the Mid -west radio con- Killing Summer Slump vention to be held in Des Moines Febru- ary 23 and 24.The other members on 11) W the general committee are J. M. Camp, Discussed y riton secretary, and Lee L. Wissler and H. B. Sixsmith. Capt. J. W. Barber, Addressing Radio Manufacturers Association The complete list of committees chosen to arrange the details of thisfirst con- in New York, Suggests Transatlantic Broadcasts to Stim- vention of dealers, broadcasters and listeners is as follows: ulate World -Wide Interest During the Hot Weather Publicity-HughB.Lee,Henry A. -Compares Conditions in Two Countries Wallace, E. R. Gray, C. T. Higgins, Rod- neySelby,JohnMcCarroll,Graham Stewart, Irwin Femrite, J. A. Rawlings,. By Herman Bernard in Great Britain. We should have more Jos. F. Hearst, E. N. Hopkins. stations and interest the public in better Broadcasting-W.H.Heinz,Dean. How to take the slump out of Summer sets. Of course, our receivers are not so Cole, Jack Whitney, E T. Collins. radio business was discussed by Capt. J. selective as yours, because there is need Arrangements-E. N. Hopkins, George W. Barber, of the Brownie Wireless Co. for that, the stations not being numerous enough.But everything isinfavor ofHamilton, Ed O'Dea, Harry W. Warren,. of Great Britain, Ltd., before the Radio C.C. Gardner, H. E. Bowman, J.C. Manufacturers Association,Inc.,at theconditions as they exist in this country regular monthly luncheon at the Hotel (the United States). Our difficulty is that Hammond, R C. Hopley, H. E Sorenson,. Commodore, New York City. we are a poor country, while you are a William H. Metz. Capt. Barber, then on one of his several rich country, and we have to make sets Program-H. B. Sixsmith, FrancisSt.. visits to this country, disclosed the results that suit the meagre pocketbooks of ourRustell, J. M. Camp, H. F. White, E. M.. of his comparative observations. He said workman." Petersburg, Joe Carmichael, Leo L. Wis- thecondition ofradiointheUnited The speaker commented adversely on sler, V. L. Thomas. States, even with the multiplicity of sta-the recent transfer of broadcasting: man- Finance-Ed.O'Dea,F. A.Beatty,. tions, was far better than that in England. agement from theBritish Broadcasting George Hamilton, H. R. Collier, V. L. As for price cutting, he said that was Company (privately owned) to the Gen- Thomas. a problem in the British Isles, too, but eral Post Office. He deplored the effect of Entertainment-Mort Zucker, Gordon that the Government helped the manu- putting radio into politics and said he had Lathrop, Ralph Townsend, Ralph Starr,. facturer.The owner orlicenseeofa been told that since the change of man-John Rober, R. H. Miller, R. H. Castner. patent is protected against the sale of his agement the programs were inferior. He product at less than the standard price. prophesied there would be debates in Par- Also, if one does not have a patent, the liament as to why one woman singer, from New Owners Begin trade association has a "stop list" that a given city, was paid more than another makes itvirtually impossible for an of-woman from another city, such arguments Making Myers Tubes fending retail or jobber to get any more being due to sectional feeling, rather than The purchase of the Myers Corporation, goods.Neither of theseplans,itwas toartistic considerationsinwhich thewas made recently and the new owners pointed out, obtains in the United Statespublic is concerned. began operation of the plant under their due to legal reasons. own management. Issues Two Warnings The corporation name, well-known for Better Business for Summer "Whatever happens," he warned, "nevera number of years throughout the radio As for improving Summer business, radio letcontrolof radio programs inyour industry, is retained by the new owners, manufacturers in England realized "itis country come into political hands." who have announced that the same high always Winter somewhere," so cultivated Another warning was that a joint asso- standards of manufacture and inspection overseas markets during "English Sum- ciationof manufacturers,retailersand whichmadeMyers'tubesfavorably mers." He counseled Americans to do the jobbers was unpracticable, as the Britishknown to the trade and the consumers same, but more particularly to assume Radio Trade Association "blew up" after will be maintained. The plant at Cleve- world leadership in exciting Summer in-the dealers and jobbers had been admitted landisbeing fitted with new and im- terestinradio, and arranging interna- to membership, and had to be reorganized proved equipment to increase production tional programs, if need be by short wave on a strictly manufacturer basis. and enablethe reorganized corporation transmission and broadcast relay. "I have a deep sympathy and respectto meet the growing demand for high "We, too, are troubled with the bogey-for the dealer and the jobber," he hasten- quality radio tubes. if you call it that-of seasonal business," ed to add, "and I make this suggestion All of the executives of the reorganized said Capt. Barber, "by which I mean the just as much in their behalf asin anycorporation have had years of manufac- drop in the curve that almost paralyzes other." turing and sales experience and have given business for a number of months in the The meeting was the second largest considerable study to the radio industry year. But it is always Winter somewhere, ever held by the R. M. A. in New York and to the trend of consumer demand. The so we cultivate the overseas markets. City. There were 75 persons present, or research and engineering departments are "It is unfortunate that something can't two fewer, than the record number. The headed by engineers who have attained be done internationally to flatten out theChicago meeting recently set a new rec- unusual success in the radio field. curve, for instance, international broadcast ord -53. arrangements to make radio a universal, The R. M. A. trade show will be held non -seasonal commodity. in the Stevens Hotel Chicago, June 13 to Dealer Started Career "America-it may be trite to say it-is 18.Of the 20,000 square feet of space the melting pot of all nations. Therefore available, 11,175 feet were sold without a With Store In Home itis most logicalfor you toinstitute personal visit for solicitation, B. W. Ru- Portsmouth, Va. broadcast arrangements, perhaps on shortark reported. The Stanley Radio Company owes its waves for rebroadcast by stations on their growth to D. E. Stanley, its owner, who, regular wavelengths, to appeal to the sep- realizing, when the radio industry was arate sections of your nationalities when Centralab Makes in its infancy, the importance of what it their thoughts run not along radio lines Selector Devicemight develop into,utilizedhis knowl- but to outdoor sports. edge of radio, which he acquired at the Predicts International Programs A new device designedtogivesets Navy Yard, and opened up a small es- greater selectivity on the low broadcast tablishment in his home. "Before many years you will no doubt waves, where congestion is greatest, has be receiving regular trans -Atlantic broad- recently made its appearance.It is a new The fine work he put out and his casts." product of the Central Radio Laboratories familiarity with radio increased hiscli- The Captain also discussed receivers inof Milwaukee, pioneer variable resistanceentele to such an extent that he was the two countries. The most popular typemanufacturers,andisknownasthe forced to move to larger quarters on in Great Britain, he reported, is the two - Centralab Short Wave Selector.Stoner County St.There his store quickly won tube set.By adding a stage of audio & Heath, Inc., 122 Greenwich Street. New favor. sufficient volume is obtained to operate aYork City, are distributors for the eastern speaker. territory. FIRE IN BOSTON STORE Stations there are about 100 miles apart, This device can be connected to any Boston so crystal sets are in high favor. He saidset in a few minutes without making any Fire recently, destroyedabout$200 his company makes 1,000 such sets a day. change in its internal connections, and is worthofreceiversand apparatusin A good crystal set, at $2.50, and a pair of provided with a switch to cut itin andMack's Radio and Battery store at 399 earphones constitute an installation. out, as desired. In addition this device is Ferry St.The fire started in the ware - "I would be delighted," he said "to seeneat and compact, and can be mountedroom and had gained headway before the more expensive setsin greater demandon the front panel of the set. fire apparatus arrived. January 29, 1927 RADIO WORLD 211 39,000 DeForest Shares Literature andoyalty for Croslley Wanted 'THE names of readers of RADIO WORLD who desireliterature fromradio job- Cincinnati Manufacturer Elected President of Jersey Company bers and dealers are published a, RADIO WORLD on request of thereader.The and Will Run It-Fee Is Three Per Cent. of First blank below may be used, or a poet card or letter will do instead. $3,000,000 Net Sales RADIO WORLD, 145 West 45th Bt., N. Y. City. Complying with the authorized agree- tent to develop its business and to enable I desire to receive radio literature ments, allowed by the Court of Chancery itto occupy the positioninthe radio of New Jersey, between the DeForestfield to which its name and other rights Name Radio Company of Jersey City and Powelentitle it." Crosley,Jr.,prominent Cincinnati radio The DeForest Conwany will still main- Address manufacturer, a new Board of Directorstain its name, accdfding to Mr. Crosley, City or town and group ofofficersof the DeForestand not change or submerge its identity Company have been elected. in any way.As a compensation for his State Mr. Crosley was elected president andwork, Mr. Crosley will receive 39,000 of the Dr. Lee DeForest was elected vice presi-211,000 shares of treasury stock outstand- F. L. Pittman, 103 3Patent Office, Washington,. dent and consulting engineer.The board ing and 3 per cent. commission -on the D. C. of directors consists of Mr. Crosley, Dr.first $3,000,000 of annual net sales. Radio Engineering andSupplyCo.,323Le - DeForest,LewisM. tang Building, Omaha, Neb. Crosley,Charles An announcement from Public Rela- William Adams, 4622 Pennsylvania St., Frank - Sawyer and R. E. Field ofCincinnati, tions,Inc.,383 Madison Avenue, New ford, Philadelphia, Pa. James I. Bush and Arthur D. Lord ofYork City, set forth: JohnLeather, 45 OntarioSt.,Schenectady,. New York. "Powel Crosley, Jr. created a radio Gen- N. Y. AlpinH.MacDonald, 1722Hamaton "I have been familiar for a long timeeral Motors when he recently added con- Trenton, N. J. with the affairs and business and difficul- trol of the De Forest Radio Company to Roy Scott,;517 Plymouth Ave., Bronx, N. Y.. tiesof the DeForest Radio Company,"his already tremendous holdings in the in- City. said Mr. Crosley. William 13. Leonard, Liberty, Ind. dustry.The Cincinnati manufacturer ac- Harry Liedlich, Riverhead, N. Y. I have always believed that the namequired not only the immensely valuable Ned Biffle, Paul Valley, Pauls Valley, Okla - DeForest and certain other rights of theDe Forest basic patents, but a modern Claud Gerlach, 410 Heath, Logansport, Ind. company could be made of great value. tubeplantwithacapacityof10,000 W. Clarke, 318 Rhodes Ave., Toronto, Chitarics Canada. "After giving considerable study to theaudions per day and the services of Dr. F. J. Carow, 715 Balfest, Toledo, 0. matter, and at the request ofa largeLee De Forest, 'father of Radio,' as chief L. E. Williams, 49 Union Ave., Portland, Ore. number of stockholders, Ihave enteredconsulting engineer. He has already pro- Waldo Stevens, Chester, Utah. into an agreement for the operation and duced and sold 1,500,000 radio instruments A. N. Kingsafer, 209 South Carrol, South Bend, management of the company with the in- Ind. -the world's largest radio manufacturer." Alton H.Brouno,540StateSt.,Watertown. N. Y. H. F. Murphy, 24 Cottage Place, East Orange, Openshaw Accepts. New Resistance Booklet N. J. C. W. Schwartz,434 West Grand St.,Eliza- Position With Pilot Covers Big Field beth, N. J. Charles W. Biel, 88 Johnson Park, Buffalo, N. Y. Martin Openshaw, has resigned from The Ward Leonard Electric Company Rthert E. Noose, 213 North State St., Indian. the Radiall Company, manufacturers ofof Mount Vernon, N. Y., have just pub- apolis, Ind. Amperites, to accept the post as general Earl Radio Co., 102 Eaton St., Buffalo, N. Y. lished a booklet, "How to Use Resistance J. C. Richard, 220 Sunnyside Ave., Mill Valley, sales manager ofPilotElectric Manu-in Radio," covering the various uses of Cal. facturing Company, Inc., Brooklyn, resistance in radio circuts. H.B.Graeff,826 South CoronadoSt.,Los N. Y. Power amplifier and high -voltage plate Angeles,Cal. The job of piloting the sales ofthe B. L Newhouse, 2217East34thSt.,Minne- Pilot supply units popular today have brought apolis, Minn. organization, withitstremendous the subject of radio resistances and the C. L Coleman,701 CherrySt.,Chattanooga, output,offersamplescopeforthe Tenn. problems attached totheir useto the EdwinJacob, 317 SouthPierceSt.,New dynamic energy which has made Open- attention of the experimentor. Orleans, La. shaw one of the well-known figures in Included in the Ward Leonard booklet John Blake,131ElliotSt..Brattleboro, Vt. the radio industry.Under his guidance Hardus Sorkness, Hemet, Calif. is a non -technical presentation of the en- R. E. Renfrow, 1112 Dawson Ave., Long Beach, the well known Pilot policy will be con-tire "current supply" question and much Cal. tinued, namely "From raw materials toother material of interest to fans. E. W. Duchman, 1064 East 94th St., Brooklyn, finished product under one roof."This N. Y. will assure the continuance of the price ** Thomas C. Wood, Box 2A, R. D. 1, Menlo Park, * Cal. policy which has given Pilot prominence Miami, Fla. FredJ.Merklein, 321 MarionSt.,Brooklyn, in the parts field for over nineteen years. The Guy H. Robinson Electrical Company, N. Y. In addition G.C.Dibrell,803C.St.,N.W., Ardmore, to directing the destiny of wholesale and retail radio dealers, 104 N. E. Okla Pilot sales, Openshaw will also handle the FortiethStreet, Miami, Fla.,recently an- C. H. Colby, Benson, Minn. Beacon Radio Manufacturing Company,nounced a new unit which is known as the P. W. Frederick, Mansfield, 0. makers of Trinity Receivers. E. Scheffknecht, 1731 North 17th, Belleville, IR. "Crosley Lowave," designed to bring in short Eduard Martin, 2040 North Laurence St., Phila- wave stations.The unit can be used in con- delphia,Pa. nection with any radio set, it is said.It uses Carl H. Miller, P. 0. Box 283, Rockton, See Jay Batteries - Harry Moore, 105 West 28thSt., Jacksonville. three 301-A tubes or their equivalent, picks Fla. Are in Great Demandup the short wave station on its wave length C. B. Noe, 763 Elmwood St., Jackson, Mich. The See Jay Battery Company, 913 and translatesits frequency to one within L H. Durgan, 8 Leighton St., Waterville, Me. Brook Avenue, New York City, is running thebandofpresentbroadcasting.This night and day to keep up with orders, opens up to interested radio fans an oppor- NEW CORPORATIONS showing that this line of batteries stands tunity to listen to what is being broadcast on Radio Sales Corp., 326 Milburn Ave., Milburn, high in popular favor among fans. the other wave lengths, including WLW, N.J.,radioandelectricalequipment; 125,000. This (Incorporated under the laws of New Jersey). concern manufacturers a full line of gen- which will be simultaneously broadcasting on Triangle Broadcasters, 4147 Broadway, Chicago, uine alkaline element, rechargeable B bat- 52 meters almost immediately,itisan- own and operate a radio broadcasting station; teries to meet every radio need.In linenounced. WGY, KDKA and other stations $5,000; Richard W. Hoffman, Stanley A. Matas, with the trend toward power supply, the Min Nelson.(Attys.Schwartz and Cooper, 105 will alto be broadcasting on short waves. West Monroe St.,Chicago,Ill. See Jay Power Unit provides noiseless, The Merola is another unit for magnetic Helicon Radioondenser Corp., 215 De Feder- uniform supply. This unit is plugged in electric reproduction thatis announced by mand Building,Peoria,Ill.,manufactureradio on the power line and left alone.Itis this company. This is an electrical repro- appliances and other mechanical appliances, so) made in several models from 100 volts to shares of no par values; H. F. Drobisch, F.C. ducer which is intended to be used to con- SchaulhauserS. F. McGrath.(Attys., McGrath the maximum voltage for power tubes. vert an ordinary phonograph by means of a and Stone, Jefferson, Peoria, Ill.). Safe delivery is assured and It is covered radio set into an electrical phonograph. NormanElectricCorp., N.Y.City,radio: by a money -back guarantee. An illus- $10,000;S. J. Goldberg, M. J. Levine, A. Eisen- * ** stat.(Atty., D. L. Sprung, 7 East 42nd St., N. trated 32 page booklet on power supply Y. City). troubles will be sent by this concern on King City, Mo. Broadway Broadcasters, N. Y. City, radio broad- request. Thomas Abbott, who recently went into casting, $20,000; S. Gelb, C. M. Warburton. (Atty., the radio business in King City, Mo., open- L. J. Feinstein. 1,440 Broadway, N. Y. City). Radio Equipment House,Inc.,New Britain. Sacramento, Cal. ing up the Abbott Radio Shop, is having Conn.,Frederick R Potter, W. W. Marshall, William P. Carmody of the Wright & quite a lot of success in this new business en- Louis W. Keith.(Incorporated under the laws Kimbrough Company,recently announced ter p r ise. Abbott has calls night and day to of Connecticut). that Bert Norton opened up a complete radiodoctor sick radios. He is agent for the MERGERS store and repair shop at 1005 Thirteenth St. Richardson Radio,N.Y.City,mergersthe Thorola and the Grebe Synchrophase radios. Cornell Electric Mfg. Co. 22 RADIO WORLD January 29, 1927 Western Electric AT YOUR SERVICE Denies It Will Stop Cone Manufacture Rumors that the Western Electric Com- pany contemplates placing a radio receiving set on the market have been met with Remedying Noises in a Receiver an official statement from the company's headquarters in New York that at pres- This department is conducted by Robert high.Likewise, a joint buried in a large ent no such move is contemplated. The L. Eichberg, director of the Extension Di- mass of solder may not be tightly stuck.company continues, however,to manu- vision of the Federated Radio Trade School,That goes to show that economy is notfacture a radio receivingsetdesigned 4464 Cass Ave., Detroit, Mich. All questions the only reason for using the smallest specifically for use with its public address regarding theconstruction, repair,selling, possible amount of solder in making a systems and radio telephone broadcasting merchandising and advertising of radio ap-joint.When the terminal of a wire is equipments. paratus should he sent direct to Mr. Eich-fastened by means of a screw or nut, see Another report which has been circu- berg at that address, where they willbe that itis tightly held.Use`a lock -nutlated from time to time was that Western promptly answered.The answers to ques- Electric loud speakers were to be with- or lock -washer to intike sure that thedrawn from sale to the public. It is stated tions of general interest will be printed here. joint remains tight.It might also be well now that there is no basis whatever for All others will be answered by a personal tomentionherethatsolderedjoints thisreport.Western Electric was the letter from Mr. Eichberg. By a special ar-wherein acid or paste is used may be alldefendant in a suit brought by the Lekto-- rangement RADIO WORLD isabletooffer right for a time, but are likely to cor-phone Corporation for infringements of this service free to all readers. rodelater,unlesstheutmost careis itspatents on thecone typeof loud It is a very simple matter to determinetaken to remove all traces of flux after thespeaker. It successfully defended this suit whether noises are originating in the au-job is completed. in the United States District Court during dio end of the set.It is necessary only The test for a loose wiring joint is tothe Summer, and last week the Circuit to connect a pair of phones across thegrasp each wire firmly with a pair ofCourt of Appeals of the Second Circuit primary of the first transformer or re- pliers, and shake it.The crackle will beaffirmed the decision of Judge Thatcher in sistance coupler.If the noises continue,heard loudest when the wire which con- thelower court and held that the Western although in a lesser degree, they originate tains the poor joint is shaken.In mak- Electric cone speaker did not infringe. in the detector or radio frequency stages. ing this check-up, do not overlook the This decision confirms the position taken But if no noise is heard, the audio ampli- speaker cords, or the B and C batteryby Western Electric from the beginning leads to the set. of the controversy, which arose after its fier is at fault.The problem is to deter- cone type loud speaker became popular mine which piece of apparatus is causing It is also advisable to check over thewith radio enthusiasts. the trouble, and then to rectify the defect. contacts in the jacks, to ascertain whether 'While the line or not they are clean and tight.They has never been widely exploited, the pro- How to Proceed may be cleaned with very fine sand paper, duction of speakers has never been stop- The first thing to do is to find whichand tightened by bending.The tubeped and under this decision they will con- audio stage isthe source of the inter-prongs and socket contacts should alsotinue to be available to the public. ference.This is done in the same man- be kept bright by the occasional applica- ner as described before, connecting the tion of sandpaper. Aerovox Wireless phones across each transformer primary. The first noise will be heard immediately Questions and Answers Moves to Brooklyn after the offending stage. The fault may A YEAR AGO at this time I ordered The slogan of the Aerovox Wireless liein the tube, socket, transformer, ora Diamond of the Air kit from a New Corporation, "Built Better," has evidently wiring.Once the exact location is found, York firm.The parts came 0. K., but been lived up to by this well-known con- the remedy is usually but a few moments' I have been unable to make the last stage cern its own reward, for work. work. The receiver works at Det. outputthe enormous demand for their products The most frequent symptom is a high- 0. K., but I cannot get it to operate at has necessitated their removal to new and pitched, continuous whistle, heard no mat-speaker output. By taking a tube out of largerquartersat 60-72Washington ter whether a station is tuned -in, when-the socket and using phones in speaker Street, Brooklyn.The plant was in full ever the filaments are lighted.This is output it is possible to hear faintly.I am swing without losing one hour of produc- generally caused by the impedance of the using CX-301-A tubes in first and sec-tion and with no delay in shipping tocus- transformer being incorrectly matched to tomers. and isstill a 24 -hour schedule. ond sockets and other tubesinthird. Thisconcernmanufactureshigh-grade the impedance of the tube.Connecting a fourth and fifth. fixed mica condensers, filter condensers, .001 or .002 mfd. fixed across the primary H. L. Fuller. power supply condensers, blocks and La- or a .5of1 megohm resistance across I would advise you, first, to check over vite resistances.Their products are used the secondary of the transformer usuallythe entire audio end of your set.First by more than 200 leading manufacturers will correct the fault.Sometimes a com-connect the phones to the output of the of radio receivers and B eliminators, and bination of both is needed.A micro - detector and see how strongly you can have been approved by M. I.T., Yale phonic tube will show similar symptoms,get a signal.Then try the phones in theUniversity and the leading radio publica- but the noise produced will be more likeoutput of each audio tube.If signals tions.Their products have been specified that of a siren, starting faintly and build-from each audio tube are not louder thanin successful circuits by authorities such ing up to a wail.It can be stopped infrom the ones preceding it,test out theas R. E. Lacault, Lewis Winner, James H. almost allcases by wrapping the tubecondensers and resistances, using a bat-Carroll and others. with electricians' tape or adhesive plaster, tery and voltmeter in series for the con- Itis only a year ago that they had to or by using one of the special devices on densers, and a battery and phones indouble their floor space at their old head- the market for the purpose of deadening seriesfor the resistances.The meterquarters, 489 Broome Street. New York tubenoises,e.g.,the McDonald howl should show no reading when connectedCity, and now they have to quadruple it. arrester. inseries with the condenser.A clickAny inquiries as to Aerovox products and their uses should be sent to thenew ad- Defective Sockets should be heard in the phones when they dress. are connected inseries with eachre- A "crackling" noise denotes poor con- sistance.Disconnect allbatteries from tact in ninety-nine cases out of a hundred.the set, and remove the tubes when mak- DAVIS REPORTS ON 1926 And in the great majority of these casesing the tests.I am assuming that you Pittsburgh, Pa. the trouble lies in poor contact between are using the proper values of condensers The application of crystal controlto the tube prongs and the contacts in the and leaks, and that you are placing thetransmitters, enabling broadcast stations socket.In the old V type sockets, the lower resistances in the plate circuits andto keep exactly on their assignedwave- prongs may be bent upward so that the the higher ones in the grid circuits,as lengths, and innumerable refinements in pressure which they exert on prongs will instructions indicate, also that your jackstransmittingandreceivingequipment be greater.The newer X type sockets are all in good condition, particularly thewere the outstanding radio developments have variously shaped contacts which may one in the first stage. of 1926, is the belief of H. P. Davis, vice be bent, when necessary, to give more * * * president of the Westinghouse Electric tension.A cracked socket should and Manufacturing Company. al- I HAVE a three -tube three -circuitset, ways be discarded, because dust or otherI would like to make a five -tube set.Let conductive material lodging in the crackme know what to do. WAR ON MISREPRESENTATION is apt to cause leakage of current, with L. D. McHale. Washington. consequent noise or weakening of signals. Sets of the following types are giving War has been declared by theRadio Shaking the tube gently while the set isconsistently good results inall sections Merchants Association on dealerswho in operation will disclose poor contact inof the country. misrepresenttheequipment The socket. (1) Tuned Radio Fre- theysell quency Set;(2) Neutrodyne;(3)Dia- either orally or through advertisements. Unless a hot iron is used with rosin- mond of the Air;(4) Browning Drake. The Washington Association has alsoini- core solder, a joint may be stuck withThe two last named sets use resistancetiated a program of education of dealers rosin instead of metal.This joint may coupled amplification intheir five tubein order that intelligent service andadvice - appear tight, butitsresistance will be models. may be rendered to buyers and owners of sets. January 29, 1927 RADIO WORLD 23 New Vitalitone Cone Is of Ship ModelLektophone Is Loser The Vitalitone Radio Corporation, 88 University Place, New York City,has In Cone Patent Suit placedonthemarketanexquisitely cone modelledspeaker. A Trenton Judge Dismisses Complaint Made Against Brandes for beautifulreal model of a gal- Alleged Infringement, Contradicting Findings in Other lant 17th Cen- Jurisdictions-G. E. Defeated on Tungsten Filament turyCrusader ship,executed in statuary re- After the long legal struggle, the Lek- sales profits.It served as a test suit, as lief and colored tophoneCorporationsuitagainstthewell, since many other firms are making mostartisti- Brandes Products Corporation, for patentthis type of speaker. cally in an- infringement on loud speakers using the Some electrical concerns already had tique poli- popular cone principle, was dismissed bypaid big royalties, some running as high chrome,sets as $200,000, as in the case of the R. C. A., off the cone.Base and edges are finished Judge Joseph L. Bodine of the Federal to match. The cone itself isthe newestDistrict Court, Trenton, N. J.This de-to the Lektophone Corporation for the perfectedcision was at variance with two others privilegeof manufacturing andselling development of the Vitalitone, rendered in New York courts recently. speakers employing the coneprinciple. afterlong and careful experimentation Lektophone had sought to restrain theAccording to Judge Bodine, however, the and research by the Vitalitone staffof device was not covered by an inviolable engineers.Itis actuated by the power- Brandes Corporation from manufacturing, ful Vitalitone adjustable unit and will not any more speakers and to rebate on all patent. rattle or buzz and issold under an un- qualified guarantee.It combines a real General Electric Ductile Tungsten Patent Is Upset reproducing instrument with an ornament that will do justice to the finest of homes. Wilmington, Del. of tungsten to be an inherent quality of Literature will be sent upon application The suit of the General Electric Com-the metal and consequently not patent- to the above concern. pany, begun in November, 1925, againstable, -and therefore dismissed the suit. the De Forest Radio Corporation, for in- According to persons conected with the fringement of the patent dealing withGeneral Electric Company, further action Three New Directors specific improvements of tungsten, as well will be taken.Theystatethat much as the preparing of this metal for fila-money was spent on research on the pos- for Wisconsin Tradesments, also the manufacture and sale ofsibilities of this metal, and can not see Milwaukee, Wis. tubes using ductile tungstein, was decidedwhy other concerns should be ableto TheWisconsinRadioTradesasso- in favor of the De Forset Corporation. produce tubes using the element. ciation,ataspecialmeeting,elected Federal Judge Morris held the ductility An appeal is expected. three new members to the board of directors of the organization.With this election the association will have complete representation inallbranches of$60,000 Load of Gold 75 -Piece Orchestra to the retail and wholesale radio trade. The new directors are Charles Krech Overtaxes Batcheller Play Often at NAA ofthe Krech ElectricCo., Henry M. Washington. Washington. Stuessy of the Kesselman-O'Driscoll One of the pet theories of Supervisor Sponsored by the Pan-American Union, and Clarence Bates of the Bates Radioof Radio Arthur Batcheller, at New York, a. new seventy-five piece orchestra, to be corporation.They replace Jack Brindleyhas been exploded. known as the "United Service Orchestra," of La Crosse, C. J. Quinn of Neenah and Not so long ago Mr. Batcheller made a has just been organized and will begin D. N. Kasson .of Milwaukee, respectively.visit to the mint with a friend. A guidepractice. The orchestra will be under the was assigned to show them through. Dur-joint conductorship of Lieutenant Charles Magnatron Tube Factory ing thetrip of inspection, Mr. BatchellerBenter, director of the Navy Band, and paused before a stack of gold bars andCaptain William J. Stannard, director of Badly Damaged by Firewished he had as many of them as hethe Army band.It will be featured in Fire recently destroyed the interior ofcould carry away with him. concerts soon to be given in the Hall the two-story brick factory building of "I'd get a nice car, a yacht and a radio of the Americans at the Pan-American the Connewey Electric Company, manu-set," he declared, "and alotofother Building and broadcast by the Navy Yard facturers of radio bulbs, at 406-408 Jef-things." Station, NAA. ferson Street, Hoboken, N. J.The origin "How much gold do you think you can Designed principally for broadcasting, of the fire was not determined, and therecarry?" queried his friend. the orchestra will be unique in thatit was no one inthebuilding when the willlay unusual stresson thebasses. blaze was discovered by a policeman. "Enough to do me for life," retored Mr. Eight double basses, twice the number Many familiesliving in frame housesBatcheller, "or break my back trying." generally used, will be included. Music in the neighborhood went to the street "Well, I'll bet you that you can't carry of the New World will be featured in the when, for a time, the blaze threatened $100,000 worth of gold," replied the friend. concerts and visiting Latin American art- to spread.The firemen confineditto The bet was made, and the guide oblig- ists are expected to be invited to appear the factory building. ingly piled gold bars onto Mr. Batcheller's from time to time. The company makes Magnatron tubes.outstretched arms. When $40,000 was on The first concert of the present season his arms, he began to look embarrassed. in which the new orchestra will appear $50,000 and he was uncomfortable; $55,000 and he began to stagger. Before $60,000 will be the thirty-third of these given NEWS FLASHES were piled' on his arms, he had to call a under the auspices of the Pan-American Spokane, Wash. halt.It would have been impossible for Union for the purpose of creating in this R. L. Strickle, vice-president and man-him to carry $50,000 around a block, he country a better knowledge of the music ager of the March-Strickle Motor Com-said later and added: of Central and South Americn.It will pany of this city, recently announced the "It's almost worth what I lost to have be held some time next month. inclusionofaradio department. The the feel of so much gold on my arms." popular Day -Fan receiving sets will be Chief Radio Supervisor W. D. Terrell handled, throughout the state of Wash-when he heard the story was willing to Sees Big Field in Europe ington and Northern Idaho. bet anybody that if he were offered $100,- Radio will in time mean more to Europe The Van Ausdale-Hoffmane Company000 he could carry it around a block onthan it has meant to America, predicts of this city, who handle the A -C Super- one trip. Maria Kurenko, the Russian operatic so- tone,Crowley, Mohawk and Supertone prano, who is a native of Tomsk, Siberia, sets, have added another receiver to this and who recently offered a recital in the line, the Grebe Synchrophase. U. S. -SWEDEN 'PHONE SOON Atwater Kent series of Sunday night con- * * * Stockholm, Sweden. certs which was broadcast from a chain Tulsa, Okla. Director Lignell of the Government'sof 19 stations. The Alhambra Radio Company whichBoard of Telephones and Telegraphs, re- At an early age Mme. Kurenko emi- recentlyconsolidatedwiththeRadiocently announced that wireless telephone grated with her parents to Moscow. Her Products Company, opened up newquar-servicebetweenhiscountryandthe musical education started at the age of ters, at 1309 East Fifteenth St. The Ra-UnitedStatesistobe arranged very 12. Later she became a pupil of the dio Products Company moved itsstock shortly.Regular telephone service with famous Mazetti, at the Moscow Conser- from 315 South Boulder Ave. to both theLondon, via theContinent,as well as vatory,simultaneouslybeginningthe old Alhambra store, at 1447 South PeoriaBerlin, Paris, Vienna and other European study of law at the University of Moss Ave., and to the new enlarged quarters. capitals are now in use in this country. cow. 24 RADIO WORLD January 29, 1927

Good Back Numbers of RADIO WORLD AROUND THE TRADE CIRCUIT The following illustrated articles have ap- peared in recent issues of RADIO WORLD: Seattle, Wash. Allegan, Mich. 1926: A new radio store, known as the Junc- According toHollis Baker, manager tion Radio and Supply Company, has been of the Baker and Company factory of this June 5-Five-Tube Compact Receiver, byJ.E. Anderson. A TesterforTubeCircuits,by opened at the Junction by H. L Ward,city, plans have been completed for the SpencerHood. ProblemsofPortables, by inthe Junction Building, a few doorsconsolidation of his company withthe Hugo Gernsback. west of the West Seattle State Bank. Allegan Furniture Shops, also that papers June19--SelectIvity's AmazingCoil,by3. K Anderson.The Light5 -Tube PortableSet. They will handle a fullline of Radiolahave been made out for the purchase of, by Herman Bernard. and Crosley radio sets, etc. by the consolidated companies, ithe Jew- July 3-Set with a1 -Turn Primary, by Herman Mr. Ward was formely in the radioett Radio and Phonograph Company plant, Bernard.Part 2 of the Victoreen Portable, by also in this city. The Jewett factory com- H. Bernard.Trouble Shooting Article for The and automobile electric business in Penn- Light 5 -Tube Portable. sylvania. prises three large buildings, where more July 10-A Rub In Single Control, by Herman ** than 300 persons are employed. Bernard. A DX DoubleRegenerator,by *** Capt.P. V. O'Rourke.A 2 -Tube Dry Cell The Yorkville Radio Company, No. 147 Receiver. by Samuel Schmaltz. East Eighty-sixth street, New York City,. Charleston, Ill. July 17-A Double Duty Loop Aerial, by J.E. has doubled its floor space by taking an Roy Chambers of the Chambers Radio Anderson. HowtoMeasureCoupling, by annex hi their present building. This addi- Company, this city, has recently disposed JohnRider.A1 -ControlCrystalSet,by tional space will be devoted to three deof his entire radio business and stock to Smedly Lyon& Chester Harrell of the Stewart -Harrell July 24-Why the Super -Heterodyne la the Best luxe radio salons for exhibiting rado re- Sot,by Herman Bernard.A 1 -Tube Reflex ceivers exclusively.Sid Vorzimer, presi- Electric Company.All theradios, and Receiver.by H. A. Reed. dent of the company, reports that 1926other apparatus, will be moved to new July 3I-What's BestInan AF Amplifier,by rooms on Sixth St. Paul Conely, former- Herman Bernard.A 6 -Tube Ravened Feed- was the best year in the history of hisly employed by the Chambers Radio Com- back Set, by K. B. Humphrey. business by far, and he looks forward with pany, and a highly experienced radio Aug. 7 --The 5 -tube Tabloid, by A. Spring Wit. confidence to 1927 eclipsing all previousman, will be retained by the Stewart - The wiring of Double Jack, by Samuel Lager. years. Harrell Company. Aug. I4 --The Improved Browning -Drake, by Her- manBernard(Pert1).StorageBatteries, by John A. White.

Aug. 21-A New StabilizedCircuit,by10. H. Loftin and S. Y. White (Part 1). The Brown- ing -Drake by Herman Bernard (Part 2). Aug. 28-The Constant Coupling, by H. EL Loftin PARTS FOR THE NEWK. H.-27 and S.Y. White (Part2).The Browning - Drake, by Herman Bernard (Part 3). Kenneth Harkness' latest -and greatest contributionto radio.Every kit guaranteed -Mail Sept. 4-The FourRectifierTypes.by K.B. Orders filled.Send for our list of other kits in stock. Humphrey.A Simple BatteryCharger,by J.E.Anderson. 1 K.H.-27Kit of EseenUalParts,$35.00; Hammarlimd17.piate nounting; 1 Micamold fixed condenser, .001 M. Ir.: Sept.1.I-The Beacon(3 -tubed,by James H. condensers(Mid -lineof 2 Micamold fixed condenser,.002 M.P.; 1Mica - S.L.F.); 1 'ParleyRheostat,10 1 Carroll. The 1927 Model Victoreen, by Her- ohms; Yarley mold gridleak mounting; 1Micamold gridleek, FixedResistance, 2 1 man Bernard. ohms; YarleyBattery 2or3megohms; 2Dubiller 1 1,1CFD Switch, Midget Type; 1 Yarley Pilot Light Brac- Condeneers; Sept. 2 Varlodensere Type G. 1 (.0001 4 18-The 1927VIctoreen.by ArthurH. ket;1 Max.); LYnch. Eliminator Ina Cash Box. by Paul Yarley Open Circuit Jack, Junior type; 1 Amperites(3 Type IA and 1 TYPO 112): 2 Aris- R.Fernald. 'Farley Antenna Switch, Double circuit, Junior type; tocrat Vernier Port Dials; 11 Eby Binding Poets. 1 Micamold Grid condenser, .00025 M.F. with G.L Sept. 25 --Thy Lynyb Lamr. Socket Amplifier, by engraved: 1 6Volt Lamp for Pilot Light. Arthur H. Lynch.Wiring up the Victoreen, TotalCost by Herman Bernard. $65.00 Oct.2-711e Vietoreen(Continued).by Herman PRECISION COIL CO., INC. Bernard.New Eatiamatie System,byCept. 209 CENTRE ST., N. Y. C. P.V. O'Rourke. Oct. 9-A PractAcal "A" Eliminator. by Arthur IL Lynch.Building the Eatiamatle. by Capt. P.V. O'Rourke. Oct- 16-The Bernard, by Herman Bernard.How toBox an A"Supply, byHerbert El - don't accept Hayden. Ott.23-The 5 -tube P. C.Samson, byCapt. P.V.O'Rourke.Getting DX on the Ber- nard, by Lewis Winner. a substitute Oct. 30-The Singletrol Receiver, by Herbert H. Hayden.How toGet RidofSqueals.by Herman Bernard. If your dealer happens to be out of Nov. 6-ReductionofInterference,by A. N. Goldsmith.VariatIone of Impedance., by J. El Anderson. Nov.13 ---The4 -tube HI -Power Set.by Herbert PkHayden.A Study ofEliminator.,by Herman Barnard. Bev. 20-Vital Pointers About Tubes, by Capt. P.V.O'Rourke. The4 -tube Diamond of the Air, by Herman Bernard. N.V. 27-TheAntennalessReceiver. byDr. CC Louls B. Elan (Part 1).Short Waves Yield Secrets. by IL L. Prescott. TUBES Dee. 4-The Regenerative5 -Tube Set, by Capt. P. V. O'Rourke.The 8 -tube Lincoln Super, by Sidney Stack.The Antennalesa Receiver. by Dr.Louis B. Elan(Part 2). Whaler's -it's because he sells DC Eliminator, by Lewitt Winner. so many- ee.Hal A.11. ni;eormsalVicmon kri.Iniesby. bR3,aliillG. II Insist on the Genuine. He has Anderson. CeCo Tubes orcan Dee. 18 --SelectivityonOne Tube,byEdgar quickly get them foryou Speare. Eliminating Interference,by T.E. Anderson. TheVictoreen Universal, by Ralph G. Hurd (Concluding Part). Dee. 25-A New CouplingDevice,byJ.E. CeCo Tubes specified by Kenneth Harkness Anderson. Functions of Falminators, by Her- for the KH-27 Receiver described in this issue. man Bernard. See page 4. Jan.I,I927-The 2 -Tube DeLuxe Receiver. by Arthur H. Lynch. The Twin -Choke Ampli- fier,by Kenneth Harkness. Jan. 8-Tuning Out Powerful Locale. by J.El. A New Addition to the Family Anderson A ChoiceSuperheterodyne,be Bruneten Brunn. The2 -Tube De -Lux Re- oolve,r, by Arthur H. knob (Part 2). of CeCo Tubes Jan.I5-Tbe DelatzeReceiver,by Arthur H. TYPE H DETECTOR Lynch(Part3). The Simple Meter Teat 09 cA Circuit. by Herbert H. Hayden. The Super - HeterodyneModulatorAnalyzed,byJ.B. NON - M1CROPHONICI I me pc....n/ Anderson.

Any copy, 15e. Any 7 copies, $1.00.All these 31cooks for$4.25,orstart subacriptionwith C. E. Mfg. Co., Inc. rryIssue. RADIO WORLD, 145 West45th Providence, R. I. Street, New Verb City. January 29, 1927 RADIO WORLD 25 I+ re eception L id Complete Parts for the HARKNESS to Lon Cable Leads KII1.27 Receiver

LEARER and more realistic than any set you I../have ever heard. New patented system of TWINCHOKE audio amplification gives amaz- ingeffectofrealism-clear,musical,full - roundedtone,entirelyfreefromdistortion. Tremendous volume under perfect control. An unbeatable distance -getter,too. Perfectse- lectivity-tunesindistancethroughlocals. Easy to operate. No whistles or squeals. The latest and greatest Harkness circuit. Complete Parts ONLY as specified by e Kenneth Harkness .00 (no accessories) Foundation Kit of Essentials

(Hayden) An example of cable leads that are too long.They should be cut at the receiver end so as just to reach the batteries. The battery leads in a set act as an antenna, which picks up signals the same as the regular antenna or as the loop. This pickup may be in phase or out of Again Specified phase with the regular pickup.In one case the signal is intensified; in the other For perfect filament control 4 AMPERITES are This official kit, together with a few stand- specified in the New ard parts,willenable you to build the new itis decreased.In both cases the be- Harkness KH-27.Kit contains: havior of the set is erratic. KH-27 Receiver 1 KH-27 front panel, drilled and engraved. When a loop is used the pickup by the describedinthisissue 1KH-27sub -panel,drilled, with six sockets. leads intensifies the signals from one di- 2 I.C.A. bakelite mounting brackets. d1 all 1 Condon., extension shaft,9 ins. long. rection and decrease them from the oppo- Company 3 KH-27 Coils, Ti, T2 and T3. site.In addition to this distortion effect 50FranklinSt., New York 3 KH Twhichoke Audio Couplers. re- 1 KH Output Choke Coil. Now Only of the field the cable introduces a I Instruction folder, with photos sistance and makes the circuit less selec- and step-by-step wiring dia- tive.Hence it is very important to make grams. 3500 the battery leads as short as possible, or else to encase them in a metallic sheath, which should be grounded. Twinchoke There is another objection to the use of TE Amplifier Kit long batteryleads. Thereiscertain ThisspecialkitcontainsthreeTWIN - amount of voltage drop in the wires, par- ghe"SELF-ADJUSTING"Rheostat CHOKE Couplers and one Output Choke Coil, theessentialpartsforthenewpatented ticularly in the A battery leads, and this TWINCHOKE Audio Ampli- makes it necessary to recharge the bat- fier.Complete instructions for tery oftenerthan when the leadsare building3 -stageamplifierin- short.In a circuit drawing a heavy fila- cluded with kit. $19.50 ment current,as two amperes for example, the voltage drop may amount to almost a volt in some cases. SEND NO MONEY Just check and mail the coupon below. When the postmanarrives,payhimmerelythe price indicated plus a few cents postage. You take nochancesofbeingdissatisfiedwith your purchase. Your Satisfaction Guaranteed If you are not completely satisfied we in- YA..qr stantlyrefund every penny you have paid. Selected Again We ask no questions-we make no excuses- we expect nofavors. You arethejudge. Either you aresatisfiedoryougetyour Kenneth Harkness uses money back.Mail the coupon NOW. HAMMARLUND CLIP! MAIL NOW!

Moneyammo Back GuaranteeGuarantee Coupon Condensers and Coils mimmt mama ammo K H RADIOLABORATORIES, Inc. Kenneth Harkness has recommended the best /n His New thereisIn radio for his II24 -MCYPRESS AVE., Bronx,N.Y. "KH-27" Receiver I Gentlemen: You may send me the items KH-27 Receiver I have checked ( x )below.When the post- III and among thoselineselectionsthesetbuilder For certainty of success, use the parts I man arrives with the package I will pay him willfind Mr. Harkness specifies. the price indicated plus a few cents postage. YAXLEY I I understand that if for any reason, or for no II Rheostat -10 Ohm $1.35 HAMMARLUND MFG. CO. reason, I am dissatisfied with my purchase I FloodResistance -2 Ohm .i 5 424-438 West 33rd Street New York I can return it and every cent I have paid will I MidgetBatterySwitoh .50 be instantly refunded. PilotLightBraoket .50 OpenCircuit Jack-Junior Typo .40 Uo't:B.attah:RailLo,' ( )Complete Parts for theKH-27....$65.00 Midget Antenna 8Witoh .65 I( ) Foundation Kit of Essentials $3S.00 At Your dealer's.Ifho cannot supply you, send ( ) TWINCHOKE Audio Amplifier Kit$19.10 his name with yourordorto ammarlund YAXLEY MFG. CO. PRECISION I NAME Dept.J-0 So. Clinton St. PRODUCTS : ADDRESS Chicago, 111. awn sm. 26 RADIO WORLD January 29, 1927 Children Are I-ar est BRACKET HELP Listeners to Please Very Keen In Discovering Tricks-Canadian Station Gets Their Aid In Developing Program Feature That Even Excites Grown- ups-Train Trip Is Devised With Amusing Sidelights Montreal. ularity of CNRV has been enhanced, and Children now have a definite place inthat is clearly evidenced by the increase the programs of stations, but in approach- in laudatory mail received at Vancouver ing this phase of work directors are facedand afterwards forwarded to the director with difficulties even greater than when of radio, A. R.. McEwan at Montreal, preparing entertainment fortheelders. WHEN INSTALLING a sub -base Children are notoriously keen critics, so Piano Aids Story -Telling which usesbracketsbe suretoallow much so that many professionals will not One ofthereasonsprompting Mr. about a %." extra space from the bottom attempt legerdemain in the presence ofWright to obtain the aid of children was of the panel, (right), so that when you purely juvenileaudiences.The young- the happy relationships which' has been place the panel in the cabinet, the blocks sters are seldom deceived by the perform-established between the station and the of wood used to prevent the panel from er'spatter and their keen eyes followlittle pupils of the School for the Deaf slipping will not hit the bracket and pre- every movement while they always insistand Blind, conducted by the Provincial vent insertion. on a complete explanation.Itis not al-Government at Point Grey, where a great ways easy to bring adult entertainment deal of joy and sunshine has been radiated discovery of a hungry rooster who had to thechildrens'scaleof appreciation,by meansofthebroadcasts.Ronnie to be fed and the listeners -in were asked and there are certain limitations in theMathews, not yet in the 'teen years, who to count the number of kernels of corn cycles of fairy tales and nature stories. has displayed a remarkable aptitude fordropped into the capacious crop.This Confronted by thesedifficulties,yet music and has become surprisingly pro-competition led to amusing results and desirous of acceding to the demand forficient on the piano, was chosen to act asset in motion a wave of happy laughter buvenile entertainment, George A. Wright, an aid to the station announcer.Later that surged along the Pacific Coast until roadcasting manager of CNRV, Cana-the plan developed with theestablish- it lapped against the foundations of Green dian National Railways radio station at ment of a "radio train", complete withIsland Light and drew from the keeper Vancouver, British Columbia, hit upon a conductorandengineer,with"Aunt of this most northerly of Canada's Pacific happy expedient. "Why not enlist the aid Emma" and "Uncle George" to shepherd marine sentinels the frank admission that of the children?" he asked. the young flock. The "train" gathered asthe entertainment was just as attractive Then he put his project into execution "passengers" youngsters who were knownto grown-ups as to the kiddies. with the result that the already greatpop- to the station and after the first "trip" through theair,lettersfairly showered L111,111111111I111011111 in at CNRV demanding passageon the Radiation Nuisance u "train" and insisting onhaltsat com- Samson Dual Impedance munities widely scattered along the Pac- Decreases in Canada u gives wonderful tone quality at low ific Coast from Southern California to the cost. Washington. Connects like transformer. farthest habitations in Alaska and Yukon Interference from radiating and inland over half the continent. The receivers SAMSON ELECTRIC CO. IN has been considerably reduced in Canada "conductor" proved to be the proper sortduring the past year, according to a re- CANTON MASS. of man for the position because at every port received here.There arejustas 1111111111111111111111111W halt for coal and water he played the many radiating receivers in use, it is said., piano which was part of the equipment of but they are being adjusted with some this wonderful"train".The "engineer"regard for the feelings of neighbors. also proved a remarkable fellow because To reduce interference from radiating Of course he insisted on making extraordinary visits receivers, to people along the line andonce, while the Canadian Department of Arthur Lynch designed the Ronnie was playing for the "passengers" Marine and Fisheries, which has control he fell asleep in the coals. of radio, issued a circular letter which De Luxe Lamp Socket An incident of one journey wassenttotheholderofreceiving was the licenses. The letter called attention to Receiver the trouble that could be caused by im- JIHARD RUBBERIt-properly operated equipment and pointed for use with SHEET-ROD-TUBING out that a standard 301-A receiving tube, Special Hard Rubber Parts Made to Order carefully adjusted to radiate the maximum amount of energy, has been heard "rw RADION and HARD RUBBER PANELS, ANY SIZE over a distance of more than 7,000 miles. --(Raytheon Send for Price List Fortunately the average radiating set LONG LIFE RECTIFYING TUBE S"-.' WHOLESALE RETAIL can only be heard over about one -quarter NEW YORK HARD RUBBERTURNING CO. of a mile, the circular added, but ina city 212 Centre Street New York there may be several hundred receiving sets in that area. 71%Ttf Delaware, 0. The Triple Service Company, willsoon METALLIZED N Al T 0AL open an electrical and radio store at the 1 in name corner of East Winter and Union St., un- WARRANTED FIXED RESISTORS der the management of E. M. Shisler. THE vitalimportanceof a silent, I accurate resistorcannot be over- NA T estimated. Comprisingaconcentrated in fact CeCo TUBES metallized deposit one -thousandth ofan inch thick, upon a glass core and sealed There is not a small corner of this United SPECIFIED BY States foreverwithinthetube,each inwhich NATIONAL Browning - Lynch Drake Radio Frequency Transformers, ARTHUR H. LYNCH Resistor is warranted absolutely noiseless, NATIONALVelvetVernierDialsand permanently accurate, dependable!Guar- NATIONAL Variable Condensers are not FOR THE TWO TUBE anteed accuracy -10% : in production they known and appreciated.This really applies DE LUXE RECEIVER average 5%. to the whole world. Type H-Special Detector .25; .5: 1; 2; 3: 4: 5: 6: You can draw your own conclusions about $2_50 7: 8; 9; 10 Meg., 50c..025; :09;.1 the popularityof NATIONAL Radio Set Type B X-199 $2-00 Meg., 75c.Single mounting 35c: Double, Essentials.Ask anyone that uses them. Ready to Mall in Special Mailing Cartes. 50c.If your dealer cannot supply you, Send for Bulletin 116-RW.Be sure you Upon Receipt of Money Order. send stamps, check or money order.We get genuine NATIONAL products. ship postpaid same day order is received. K. W. RADIO CO., Inc. 10 Park Place Dealers-get on our mailing list; we keep you postedon NATIONAL COMPANY, INC. New York new developments. Write us today! 4984, Engineers and Manufacturers ARTHUR H. 2 50 W. 57th St. W. A. READY, President 110 Brookline Street Cambridge, Mass. FOR ONLY 15 CENTS get full directions how LYNCH, INC. NewYork,N.Y. to build the Bernard.Radio World, 145 W. 45 St., N. Y. C. January 29, 1927 RADIO WORLD 27 1,100 Stations, Maybe; HIGH JINKS WITH, LOW AERIAL 130 Being Erected Washington. A report of the Department of Com- merce shows that the total number of stations may- reach 1,100 before June 1 unless a radio bill is enacted. That would be twice as many stations as were in operation when the Government lost control of broadcasting last July. Newly licensed stations already brings the total above 700.More than 130 stations are under construction.Plans are in progress for the construction of about 250 additional stations. The new stations reported under construction are in the following cities: Mar- blehead,Mass.;LongBeach,N.Y.; Woodbridge, N. J.; Long Island City, N. Y.; Ozone Park, N. Y.; Brooklyn, N. Y.; Richmond, Va., Columbus, Miss.; Med-. dian, Miss.; Oklahon- City, Okla.; Atoka, Okla.;San. Antonio, Texas; Memphis, Tenn. (2); Burbank. Calif.; Yuba City, Calif.; San Diego, Calif.; Los Angeles, Calif.;Bellingham,Wash.;Lewiston, Idaho; Flint, Mich.; Clevelad, Ohio; Le Roy, N. Y.; Washington, Pa.; Auburn, N. Y.; Peckley, W. Va.; Cohocton, N. Y.; Endicott, N. Y.; Cambridge, Ohio; To- ledo, Ohio;St.Paul, Minn.; Evanston, Ill.; Denver, Colo.; Ft. Riley, Kans.; De - Pere, Wisc., and Cozad, Nebr. (Herbert Photos) Dispute Is Foreseen WITH A couple of skiis and two ski -sticks 'tis entirely feasible to make an efficient Over the Long Wavespair of antenna poles.These pretty wireless enthusiasts of Lake Placid proved that Washington. statement by actua ly building one. An international dispute about the use of wavelengths for long distance wireless Write for full information regarding 1,0RADIO Y'ur ORTHOPHONIC telephony is foreseen by experts of the thecabinet,personallypickedby Fits Any Phonograph Government who have been watching Arthur H. Lynch for his own De Luxe ...... =-, Works on Any Set developmentsintheestablishmentof Lamp Socket Receiver. Easily Attached.Enjoy American -English and Canadian -English Real Music. trans -oceanic telephone service. CHELTENHAM CABINET MAKERS, Inc. Only ..... WEST 44THSTREET NEW YORK 0OWas 510.00 $.95 Use of long distance wireless telephony \ on a large scale by the entire world may TradeInquiriesinvited BLAN THE RADIOMAN never be possible because of insufficient 145 EAST 42DSTREET NEW YORK CITY waves, according to theseexperts.It would follow that the waves available for such services must be divided among the various countries by an international con- to OUTLAST ference. ...k\ The band considered most likely to be DESIGNED used for wireless telephony is between 20 and 100 meters. I n this band also are a 6rid number of other services such as long distance telegraphy,aircraft beacons,air- American. Sub -Panel Bracket Thisaluminumsub -panelbracket Isdesignedto c e "A 41 t 11, tlery- crafttelephony,governmenttelegraph accomodate differenttypesoftransformersun- stations, derneaththesub -panel. ItIs composedofnon - commercial telegraphstations, Magnetic. metal andwillfita V'.5"or7"sub - amateurs, short wave re -broadcasting, etc. panel. For radio receivers and battery eliminators. This applies a definite limitation to the Complete with screws and nuts. number of channels that could be used for SPECIAL PRICE 35c each international telephony. Atdealersordirect With the beam system, the same wave American Radio Hardware Company might be used north and south, and east Dept.Wl, 135Grand St., New York City and west simultaneously.Itisalso believed that other inventions and methods Two-Year may likewise increase the availability of Guarantee NEW channels. But it is doubted whether there Bond LOW will ever be sufficient for any very elabo- in Writing PRICES rate system such as that in use by land Famous the world over for reli. telephone companies. a ble,enduringperformance. Solid Solid Rubber Case Rubber Case lasting protection Radio Batteries against acid or leakage. ----, 6 -Volt. 100.Amperee MAKES 5,300 SETS A DAY $10.00 Approved and Listed as 110 Amperes More than 5,300 sets a day are turned Standard by Leading $12.00 out at the Atwater Kent factory, Phil- 0 -Volt. 140-Amperea \\\1\-- Authorities 113.00 adelphia, Pa. including Radio Newe Laboratories, Solid Rubber Case PopularSci.Inst. Standards, Pop. Radio Laboratories, Radio Broadcast Auto Batteries PRECISE NS MICRODENSER Laboratories, Radio in the Home and 6 -Valthio.g. Plata Lefax, Inc. e. volt la -Plata Series*Antenna Balancing Condenser $12.00 Especially Designed for the Browning -Drape Send No Money 12 -Volt P1.1. Just state number wanted and we will APOLLO $4.95 Receiver snip same day order is received, by Selected and Specified by express C.O.D. Pay expressman after Set soarradiodlaleat 18 -INCH CONE examining batteries. 6% discount for 288.8 meters for the Arthur H. Lynch cash with order. Remember, you save Newestartistically 50% on World Batteries-so aced yourVarletr-newr2,1,:trorn°,1leolt. mt designedadjustable for the De Luxe Lamp Socket Receiver order today. -elvraraleterestioS. cone speaker at' an 104Mini. Capacity,51.75 WORLD BATTERY COMPANY Dir. exceedingly 1 o W A PreciseLaboratory QualityInstrument Dept. 17 "Cheargn price. Also made in 10, 20, 30, 55 and 135 Mmf. Cap. 1219 S. Wabash Ave., Chicago, Ill. Mailordersfilled upon receipt of $4.95 PRECISE MANUFACTURING CO. Rix 'Radio Supply ROCHESTER, N. Y. New York Office: 120 Liberty Street HOW TO BUILD THE BERNARD, the beau- House, Inc. tiful 6 -tube thumb -tuning set, fully described and 5505 4th Avenue Illustrated in the Oct. 16 issue. Send 15e for a Brooklyn, New York FOR ONLY 15 CENTS get full directions how copy.Namepieces for affixing to front panel free to build the Bernard. Radio World, 145 W. 45 St., to all on special request. Radio World, 145 W. 45th N. Y. C. St., N. Y. City. 28 RADIO WORLD January 29, 1927 Business In Northwest SET INSTALLED ON AUTO'S PANEL St. Paul, Minn. Northwest radio fans bought $30,000,000 worth of radios and accessories during 1926 according to a report made by the Northwest Radio Trade association. Sales of radio receiving sets equipment increased 40 per cent to make 1926 the largest radio year in the history of Minnesota. Of thetotal amount sold,27 Twin Cities jobbers sold 68,150 radio sets, of a

value set at $7,620,000. Nine manufacturers turned out 10,550 sets during the year, with a retail value of $1,100,000. More than 22 per cent of the homes in St.Paul, Minneapolis, and Duluth now have radios, the report shows, and radio dealers have doubled in number in the Twin Cities alone, while jobbers increased from 50 to 67 during the year.

Send forFolder Geo. W. Walker Co. 6528 Carnegie Ave. Dept. B Cleveland, 0.

ANY SET DESCRIBED IN RADIO WORLD BUILT TO YOUR ORDER. WRITE M. LERNER lea Resnsen Ave. Brooklyn. N. Y.

gjA-ALpi cdtats rad Dias UX POWER TUBES Installed In any set without rewiring by Na-Aid Adapters and Connectoralds.For full Information write AldenManufacturingCo.,Dept.S-20, Springfield, Mass. SHORE TRANSFORMERS A N D CHOKES FOR EVERY RADIO POWER NEED Special Transformers Made to Order Our Prices Are Right- Write and Be Convinced (Underwood & Underwood) KEEPING pace with radio's advance, designers are getting up circuitseasily SHORE ELECTRIC CO., Inc. installed in given types of automobiles, and sturdy enough to withstand bumping. 124 Cypress Avenue, New York City The dashboard installation pictured is one very easy to tune. A loop is wound under the car's top and is grounded through a condenser to the frame. WATCH EXPIRATION OF YOUR SUBSCRIPTION I Subscribers will note that the end of their subscriptions is indicated on the labels on wrappers. If your wrapper shows a date earlier than the current leans, please send payment for renewaL Changea SEE JAY POWER UNIT in expiration dates on wrappers appear two weeks after receipt of renewal. "\..! RADIO WORLD, 145 West 45thSt., New York City.(Phones:Bryant 0558-0559./ liar* to riplA Stay _LB FILL OUT AND MAIL NOW 4. ;6 SUBSCRIPTION BLANK nt,

RADIO WORLD A combination alkaline element battery and trickle charger all in one.Price, shipped dry RADIO WORLD 145 West 45th Street, New York Cit3 withsolution,$16.00. Tubeextra,$1.00. (Just East of Broadway) 100 -volt with chemical charger, $12.00. 140 - volt, $17.00. Write for our illustrated 32 -page booklet and Please send me RADIO WORLD for months, for wkich Send No Money. Pay Bspressmas. SEE JAY BATTERY COMPANY ;please find enclosed 913 BROOK AVENUE, NEW YORK CITY -SUBSCRIPTION RATES: -Single Copy $ .15 THE TRANS -OCEAN 'PHONE Three Months 1.50 Howthe Six Months 3.02 New York -Londonradio One Year, 52 Issues 6.00 telephone system works was described Add $1.120a Year for Foreign and illustrated in the January 22 issue of Postage; 50c for Canadian Post- age. RADIO WORLD.Send 15 cents for copy, RADIO WORLD, 145 WestForty-fifth City and State Street, New York City.-Advt. January 29, 1927 RADIO WORLD 29 "The expenses for the year," said Mr. FRENCH TRAIN HAS SET ABOARD Aylesworth, "will be greatly in excess of the receipts. "And, due to the fact that all broadcasting stations in the United States are operatingataloss,and becausethe public will not permit promiscuous plug- ging the trade' broadcasting,Iexpect to see many of the smaller stations among the 600 to 700 in the country gradually disappear as their owners' interests wane and the big deficits appear. Kroblack Is Handled By Tilson & Tilson Tilson & Tilson, 154 Nassau Street, New York City, have been appointed exclusive sales distributors for the New Mountford Kroblack wire -wound resistances.These come in 10 and 20 watt capacities and test up to the most rigid specifications.They have been adopted by Thordarson and by many other leading B eliminator manufacturers. Interesting literature on these resistances will be sent upon application to Tilson & Tilson.

NEW IMPROVED (Underwood & Underwood) DIAMOND OF THE AIR KIT AN INTERIOR view of the new luxurious smoking room on the Paris -Orleans (Licensed Kit) train, in which passengers are listening into a radio concert, while the French Complete Parts $37.50 train speeds toward itsdestination.The receiver(top)contains the tuning and Send in for special proposition. amplifier for short waves; (center) long wave amplifier; and (bottom) the audio B C L RADIO SERVICE CO. frequency power amplifier. 221 Fulton St. (RW) N. Y. C.

Fainxded All St tions Are Losing EROVOX Resistancesordene "Built Better" cannons Products ore and bc moor than 560 Money, Says Aylesworth manufacturer. of Radio 14c -rivers and 9T. Eliminator.. The National Broadcasting Company, criptive talks oncommercial products will AEROVOX WIRELESS CORP. announced that $3,800,000 will be spent be permitted. 60.72 Washington St., Brooklet', N.Y. during 1927 for providing entertainment to the.ublic.It was also said that about $15,111,000 additionalwill be spent for talent by commercial firmssponsoring Radio Mailing Lists programs over this company's chain of 27426-Radio Dealers,Retail,Per M $7.50 stations. About 't.:00,000 will be paid to 2660-RadioMfrs.,PerList 20.00 2857-Radio Jobbers,PerList 22.50 NEWEST 1027 EDITION the American Telephone and Telegraph 1847-RadioJobbersrated$5,000and Shows 184 pages of the latest cheats. up,PerList 15.00 et Company by the N. B. C. for the use of 1060-RadioMfrs.CompleteSeta.Per thenewestdevelopmentsinradio the lines and special telephone engineers, List 10.00 atattlingly low pricesGet the parts you and any otherRadioList you want.Ask ler de- want here and save money.'roe beat in who are placed at different points along tailedpricelistaallguaranteed98%'erred. Parts, MCC sets and supplies. Orders station _broadcast. filled same day received.Write for free a chain At present COPY NOW; also please send names of the N. B. C. employs 300 persons. The Trade Circular Co., Inc. one or more radio fan. expenses for thisforceisexpected to 166 W. Adams Street Chicago BARAWIK CO. be in the neighborhood of $2,500,000. The 560 Monroe Street.Chicago.U. S.A. N. B. C. has set aside $500,000 for indi- vidual talent, which will have nothing to do with commercial programs, The N. B. C. will occupy part of the new buildingatFifty-fifthStreet and MARVELOUS RESULTS Fifth Avenue, New York City, by June. It will utilize four- floors and eight stu- WITH KARAS EQUAMATIC dios. There will be an auditorium capable of seating a broadcasting orchestra of 150 THE high quality of reception of the Build This Great Receiver musicians, and 300 guests. Karas Equamatic 5 -Tube Sensation You can have an Equamatic that will sur- has swept the country.Everybody is dis- pass any other receiver ever designed- Merlin H. Aylesworth, president of the you can easily and quickly build it your- N. B. C., stated that the policy of broad- cussing Karas Equamatic selectivity, tone quality,distanceandvolume. Every self-and it will be a finer looking set casting advertising programs willcon- than any factory made set you could pos- tinue, provided only a simple form of an- Equamatic that has been built has won For the nouncement of the firm sponsoring the hosts ofenthusiastic boosters for thissibly buy, regardless of price. program isgiven. No long-winded des - great receiver.Women, especially, have small sum of 10c you can secure from us been quick to appreciate its superior re- the complete Karas Equamatic Manual, ception. And women know good reception explaining the operation and the con- when they hear it! struction of this great receiver. The Sensation of Radio Write for the Equamatic Manual Practical RADIO work Containa simple instructions and complete data Day after day the superiority of Karas on the Equamatic.Enables you to build this taught at home-at cost! Equamatic reception over every other re- receiver from Karas and other parts easily obtained from your local dealer.Write for this This school is ron, without profit, by the Michi- ceiver is being told us in hundreds of let- Manual today, filling out and mailing coupon gan Radio Trade Ase'n.Teaches what you need tersfrom every part of the country. to know for asuccessful radio career-and helps with lfic to YOU Lind a position.Has Resident and Ertension Never before has a radio receiver had Courses.Write for details. sendaddress. such an enthusiasticreception. Every KARAS ELECTRIC CO...... -.-..- -.-.__._ Equamatic builder knows the answer: No 1141 Association Building, Chicago Federated Radio Trade School otherreceiver accomplishes so much- 4464 Cass Ave., Detroit, Michigan gives such startling results-is so easy to KARAS ELECTRIC CO. Send information on your courses,without obli- tune-has greater volume-brings in DX I 1141AssociationBuilding, Chicago- gating me. ! enclose 10o for which please send me a oopy of the localstationsso .1f tic bfanual. explaining the construction soclearly-separates youraras Ei.iva Name easily.Thos. F. Meagher, Long Island, receiver. Address N. Y., logged 40 stations in one evening, ! Name Town and State cutting right through powerfullocals. IAddress Others report even better results. City State 30 RADIO WORLD January 29, 1927 WRNY Staccatone RADIO AMERICA HEARS THE DEVIL Has Turned Cuckoo The "Staccatone," the peculiarflute- like instrument which has been transmitting an identifying signal from WRNY, New York, during lulls in the programs of that station, has been modified so that it now produces a sound exactly like that made by a cuckoo bird.Radio listeners who pass the 374 meter setting in tuning theirreceiverscan instantlyrecognize WRNY by the unmistakable chirping. The former signat broadcast by the Stacca- tone consisted of the first three bars of "The Stars and Stripes Forever."The constant repetition of these became tire- some, so the change to the more novel cuckoo tone was made. The Staccatone, which is the invention of Hugo Gernsback, is a combination of clockwork and a vacuum -tube oscillator generating audio frequencies.

201.-A Type,Vot amp. 5 -Volt Silvered Tiplets Thoriated Filament Insures Long Life Money Back Guarantee $1 Trellcott Co. Postpaid 2115 Hale Avenue 5 for Louisville, Ky. $4.50

FIFTEEN microphones were installed in the Auditorium, Chicago, from where the eNew and Improved Garden Scene from "Faust" by the ChicagoCivicOpera Company was broadcast through the combined Red and Blue Networks of the National BroadcastingCo.

KROBLAKRESISTANCES Cadman Brilliant, FiiAU ES Wire woundResistances10wattcapacity.SPE- CIFIED by Thordarson andSliver -Marshall. Used Wins Great Favor byleadingEliminator manufacturers. AT AUTHORIZED Prices-Sines750ta12,000ohms, $1.00list; One of the most FRESHMAN DEALERS ONLY 26,000 ohms, $1.25; 50,000 ohms, $1.50. R-210KroblakkitforThordarsonR-210list, popular broadcast- $4.50. ers on the airis Exclusivesalesdistributors theRev. S. TILSON & TILSON Parkes Cadman, 164NassauStreet,New York. N.Y. who speaks RADIO WORLD'S everyS u n dla y from 4:00 to 5:00 QUICK- ACTION A RADIO BARGAIN p.m.,beforethe Two of the finest complete master 7 - Men's Conference CLASSIFIED ADS. tube cabinet outfits ever built and one oftheBedford receiver in original cases just as re- Branch, Y. M. C. 10 CENTS AWORD ceived from factory at less than half A.,inBrooklyn, 10 WORDSMINIMUM. their original cost. N.Y.,whichis CASH WITH ORDER. This Is the Outfit: broadcast by 2-Master 7T Radio Consoles REV.DR. S. WEAF andthe 14-Vacuum Tubes, Type MIA PARKESCADMAN Red Network of SEND FOR PAMPHLETS OF THE GOOD- 2 -6 -Volt, 100 Amp. Storage Batteries the National MAN TUNER-In use for years and still good. 6-B Batteries, 45 volts each Broadcasting Company, whichinvolves Tested and approved by many technicallabor- 2-Aerials, Lead-in and Ground Wire tieup with stations receivable by atories. 4-Insulators, aerial L. W. Goodman, Drexel Hill, Penna. 2-Radio Phone Plugs about 75% of the people in this country. 2-Double C Batteries Rev. Cadman is known to millionsof ANY SUPER BUILT from a standard Kit, $15.00. 1-Radio Set Other sets, $10.00.Shipping charges paid one way. people inthis country for his excellent CooperCheney Radio Shoppe, Lima, Montana. method of discussing popular topics, and Mfr.'s Price $420 Our Price $200 for his brilliant answering of questions. WILL TELL YOU where to buy5 -tubesets, GUARANTY RADIO GOODS CO. $12.50, Cone Speakers $3.75, Brandes Phones $1.75. BLUE PRINT and Book, DIAMOND OF THE Tubes 50 cents each.Write Oman, 156 Concord, 145 West 45th Street, New York City AIR sent on receipt of 50c. Guaranty Radio Goods St.Paul. Minn. Co..145 West 45th Street, New York City. SPECIAL PREMIUM SUBSCRIPTIONOFFER For NEW RADIO WORLD SubscribersOrdering NOW Radio World has made arrangements This is the way to get two publications -To offer a year's subscription for any one of the following pub- -for the priceof one: -Add $1.00 a year extra for lications with one year's subscription for RADIO WORLD -Send $6.00 today for RADIO WORLD -Canadian or Foreign Postage. -for one year (regular price -Present RADIO WORLD subscribers -RADIO NEWS or -BOYS' LIFE or -for 52 numbers) -POPULAR RADIO or -RADIO DEALER or -can take advantage of this offer by -RADIO (San Francisco) or-and select any one of the other -extending subscriptions one year -SCIENCE AND INVENTION or-RADIO AGE. nine publications for twelve months. I I = -if they send renewals NOW! RADIO WORLD'S SPECIAL TWO -FOR -PRICE -OF -ONESUBSCRIPTION BLANK RADIO WORLD, 145 West 45th Street, New York City. Enclosed find $6.00 for whch send me RADIO WORLD for twelve and also without additional months (52 numbers, beginning or Boys' Life (or $10.00 for two yearlyPopular subscriptions). Radio, or Radio No other News, premium or Science with and this Invention, offer.) or Radio Dealer, or Radio (San Francisco),or Radio Age, Indicate if renewal. Name Offer Good Until StreetAddress February 25, 1927 City and State RADIO WORLD NEW BALKITE AGENCY St.Louis-A Balkliteservicestation has been opened by the Fansteel Manu- THE RADIO UNIVERSITY facturing Co., at 1415 Pine street, with A. F. Reutlinger as manager. Service will be available at this factory branch on all (Continued from page 15) Balkite radio apparatus. HOW SHOULD thethree -tubeset shown in the Radio University columns BETTER SENSITIVITY of the Oct. 30 issue of Radio World, be rewired, so that the second radiofre- Patent Pending quency tubeisnotreflexed?-Morris Has twice the anten- Merrill, Denver, Colo. nae input of any other Connect the end of 12 (primary wind- type. Savesbattery current, is 100% self - ing in plate circuit of first radio tube) to directional,makes the top terminal of the single circuit jack. yourreceivermuch Connect the bottom terminal to the B more selective. Can plus sixty-seven and ope-half volt post. be erected anywhere. In this way, the primary of AFT2 is dis- Simply installed, tug - g e d construction. connected. Disconnect,thesecondary Takespracticallyno winding of this transformer, also. Run the rOOM. grid return of the second tube to the DX Antenna Kit minus A post. The end of IA (end of Complete $13.50 primary winding in plate circuit of second Postpaid radio tube) is brought directly to the B Rooky Mountain plus sixty-seven. and one-half volt post, States & West $14.00, also. The single circuit jack at this point (Hayden) Canada $14.50.Deal- isdisconnected. You will note, that in- WHEN testing s ere -Jobbers -A gent s stead of taking the output out of the radioreceiveritis write for trade terms. second radio tube, it is taken out of theoften desirable to insert a high variable Manufactured by the first radio tube, since the reflex actionresistance in series with the plate lead, or DX LABORATORIES takes place in this tube, only. with the plate battery, particularly B plus 39 Soper St., Oceanside, Rockville Center,N. Y. *** detector.Sometimes nice adjustment of Tested and Approved by Radio World WHAT IS molybdenum?(2)-Please The voltage greatly improves reception. tell me what the following prefixes mean . deka, kilo, mega, bega. trega, deci, centi, milli, micro and bicro?-Thomas Julian, St. Louis, Mo. (1)-A natural metallic element, belong- ing to the chromium group. It, however, is The BRETWOOD found only in rnolybdenite, sheelite,etc. When found in this form, it apears as foli- ated scales, very much like graphite, except for the color, which is a deeper blue. Variable Grid Leak When used with -such reducing agents as hydrogen or carbon, molybdenum can be obtained.It is a very difficult metal to reduce toflexibility.However when in Is a Remedy for Distortion this state, itis used as a supporter for tungsten filaments inlamps.(2)-Deka equals ten, kilo equals one thousand, mega equals one million, bega equals one bil- lion, trega equals one trillion, deci equals one tenth,centiequals one hundredth, milli equals one thousandth, micro equals Precision Range, Ys to 10 Megohma one millionth, and bicro equals one bil- lionth. Much of the distortion present in radio receivers is due to an overloaded detector tube. Too much power for that lone tube to handle with fidelity.The Bretwood Variable FREE Grid Leak permits control of the grid circuit so that the NEW RADIO CATALOG maximum efficiency without distortion is achieved.Put Write Teday te Chicago Salvage Stock Storo a Bretwood Variable Grid Leak in your set and marvel at 502 S. State St., Dept. R.W., CHICAGO. U.S.A the difference! MODE THAN a score of new kits --all the latest and best-with specified parts to build them- at prime that mean big savings for you. AndaD "THE RESULTS ARE ASTONISHING^ thelatentparts andace -mufflesasadvertisedin current radii NORTH AMERICAN BRETWOOD CO. Dee. 26. magaaban. flus Dear Sirs: largest, m a t I feel as itis my duty to write and tell you that I bought a Bretwood grid leak and templatea o got fine results.I placed it in the same position as a regular fixed grid leak. up-to-datera- THE RESULTS WERE ASTONISHING.I was quite a while adjusting it to its proper dio stockLer position.It means true tone, clarity, volume and many more DX receptions. the WW1& TOWS te I have tried many other makes of all kinds and sizes, but THIS ONE IS THE BEST ehoose from YET. is this new Most people will write credentials praising results from instruments they have tried on Writ. sets that anything at all would improve, but my set, I thought, could not be improved oa. Wriear I was dumbfounded, for now I know I own a perfect set. You may use thisletterforadvertising,also name and addressforreferences yailf any kind. of SOY. From a well -satisfied user of a Bretwood Grid Leak. (Signed) GEORGE SORTWELL, - - - --18 Eng.- House,- 1915 - W. Wash. St, Indianapolis, In& NORTH AMERICAN BRETWOOD CO., 143 West 45th Street, N. Y. City Enclosed find $1.50, for which send me one Bretwood Variable Grid Leak (or $2.00 for leak with grid condenser attached) on five-day money -back guarantee. NAME STREET ADDRESS HOW TO BUILD THE BERNARD, the beau- tiful6 -tube thumb -tuning set, fully described and CITY and STATE illustrated in the Oct. 16 issue. Send 15c for a copy.Namepieces for affixing to front panel free (Inquiries Invited from the Trade) to all on special request. Radio World, 145 W. 45th St., N. Y. City. RADIO WORLD January 29, 1927 B. S. T. CONE SPEAKER Guaranteed to give Satisfaction in Tone, Volume and Appearance Adjustable to Volume Desired 18 inches in diameter edged in Gold Braid, Art Metal Basecan be placed on highly polished surface without danger of scratching.

Immediate Shipped Direct Delivery $7.50 from Factory Satisfaction Guaranteed or Money Back Tested and approved by Radio World Laboratories B. S. T. UNIT This Separate Unit is

Adaptable for any Horn, Mail Cash, Cheque or P. 0. Cabinet or Cc_i,sole Money Order B S T5 $40.00 DIRECT FROM FACTORY TO YOU SAVES HALF AND IS GUARANTEED I take great pleasure in telling you that my B.S.T. 5 -tube set isworking splendidlyinevery way, and the cabinet itselfis beautiful, and admired by all my friends. THOMAS FLARTLE, 155 Perry St., Paterson, N. J. This highly sensitive, powerful and selective BST -5 radio receiver has all up -to -the minute improvements.Heavy alum- inum automobile type chassis, shielded against stray currents and distortion.Flexible grip, Universal type sockets, eliminating microphonic noises. Has provision for battery eliminator and any power tube.Fahnestock clips on sub -panel for adjusting C battery, has voltages for power tube.Efficient on either long or short aerial, including indoor aerial.This BST -5 sets a new standard for true tone values and selectivity.This BST -5 gives greater volume than many six -tube sets and con- sumes less current. IMMEDIATE Shipment made same day we receive your cheque or DELIVERY P. 0. Money Order for $40. New model cabinet Du PoutDuca&auk; bore 21" long by 8" RADIO WORLDafr,414041I th.Rawponsiblifty el wide,height954",tot,21"byV'.Five-plywalnutveneer Tlak:aAdiesettoor GUARANTY RADIO GOODS CO. 145 West 45th St., New York