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ftln!rica's First and oil y National a io ee1' ...$11FreAgNiYAtrIVZW,1 n

Bias Resistor FallaqExposed

Condenser Action Explained ftr the Movic(

The Silver Shielded Gri(Six

Tips for Custom SetBuilders

How to Shoo the Buzz from a Speake...

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RADIO WORLD January 21, 1928

SM New ShieldedGrid Six Brings

in Australia!DURING a pouring California

rainstorm punctuated bydeafening crashes of static

and terrific interference from leakingpower lines, to quote a witness, Ken-neth G. Ormiston, operating aShielded Grid Six, forty miles outsideof Los Angeles, brought in 2BL,Sydney, Australia, on his loudspeaker. There, operating under in-terference conditions that woulddrive the average listener from hisset in despair, the Shielded Grid Sixplayed right on, bringing in stationsm Canada, east to Chicago, south toTexas, and, finally, playing 2BL onthe loud speaker, not to mentionbringing in what were later provedto be the carrier waves of a Japanesestation.

Of course, such reception is un-usual-the average man will prob-ably never hear Australia or Japan,but just the same you can be sure

that you can't get a better set than a Shielded Grid Six after what Ormiston has proven a stockkit wilt do-you can be surd that with a Shielded Grid Six you have as fine tone, distance -gettingability and selectivity as were ever combined in a single practical receiver-and what more can youask for in a radio set simple enough to be operated by the entire family?

And remember-S.-M. unconditionally guarantees that you'll get more genuine satisfaction outof the Shielded Grid Sixes than out of any other set you can buy-whether you're a DX houndor a lover of fine tone.

Fair enough, isn't it?

What Are the Shielded Grid Sixes?The new Shielded Grid Six receivers, using

three stages of tuned RF amplification withscreen grid tubes, followed by a super -sensitivedetector and the famous S. -M. two -stage audioamplifier, are just about the finest receivers youcan build. They have consistently "trimmed"every receiver against which they have beentested, even new screen grid superheterodynes,yet they're so simple and easy to build, so sureand positive in their operation-with no trickyadjustments-tint you'll simply fall in love withthem after your first five minutes of tuning.And the Shielded Grid Sixes offer all the re-finements of two and three hundred dollar fac-tory sets, in shielding, all -metal assembly, bronzefront panel, dual control vernier dials and ap-

SILVER-MARSHALL, lee.878 West Jackson Blvd., Chicago.

Please send me complete literature about the newShielded Grid Sir, for which I enclose 10c.

I

cFor the enclosed 25c please send see blueprints and

omplete building instructions on the Shielded GridSix.

pearance that is a joy to the eye of the con-noisseur or the engineer alike-a beauty thatcreates instantaneously the desire to own thefinest of sets-a Shielded Grid Six.

Two models of the Shielded Grid Six receiv-ers, using screen grid tubes, are available, types630 -SG and 630-LSG.

The 630 -SG receiver kit, designed for an-tenna operation with a 15 to 30 foot antenna(indoor and outdoor), including every nut,screw and lug requited, down to the last part,is priced at $97.00, with complete building in-structions and blueprints.

The 630-LSG receiver is exactly the sameas the 630 -SG model, except that it is intendedfor loop antenna operation only, using anystandard .00035 loop. The complete kit, includ-ing all parts, is priced at $91.50.

Silver -Marshall, Inc.NAME 878 West Jackson BoulevardADDRESS CHICAGO, ILL.

EVERY FRIDAY evening, beginning at 5:40P. M. a tea -minute talk on radio topics is delivwadiy Herman Bernard, managing editor ofRadio World, from WGBS, the Gimbel Bros. ela-tion. New York Listen in.

AR.TEFixed Condensers, Jacks,

Resistors andSwitchesCHOSEN

-as usual-FOR

S -M ShieldedGrid Sixes

Any dealer can supply.In Canada: Carter Radio Co., Ltd., Toronto

ocnec Carter Radio Co.CHICAGO

American All -Direction Antenna

A I Copper14 InchesDiameter $4.07

Gets reception from all directions. Mounts on anypole, requires no attention. Installed in a few minutes.A perfect antenna, fully guaranteed. Neat, durable, comm-pact: occupies very little sante.

If your dealer cannot supply You send money withorder direct to us and we will ship prepaid.Manufactured by AMERICAN RADIO HARDWARE CO.135 Grand Street Dept. W New York City

ShieldplateType SP -122

Shielded Grid TubeThe Greatest Forward Step Since

Invention of RadioTHIS startling new

acXievementguarantees the de-velopment of supe-rior receiving sets.Leading radio engi-neers already havedesigned circuits in-corporating the newtype SP -122 ShieldedGrid Tube. Criticsproclaim these re-ceivers the mostoutstanding devel-opment in the radioindustry.

Specified!T h e Shieldplate

Shielded Grid tube,Type SP -122, is ex-clusively specifiedfor the SilverShielded Grid Six,Hi -Q Receiver,Best's Super, theFAMOUS TYR.MAN "70" and allshielded grid cir-cuits.

Endorsed by suchleading authoritiesas Tyrman, Best,Hathaway, Silver, and recommended by

Radio News, Radio, Citizens Radio CallBook, Radio Listeners Guide, Radio World,and practically all leading metropolitannewspapers.

Mail Coupon far Complete Literature- -SHIELDPLATE TUBE CORP.

208 S. LaSalle St., Dept W, Chicago, Ill.Kindly send MEE booklet describing theShielded Grid Tube, Type SP -122, and its many

Name

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FROST -RADIORheostats Specified for the New

SILVER -MARSHALLSHIELDED GRID

RECEIVERAs usual,y Frost-Radlo wins again on Quality.

HERBERT H. FROST, Inc.Main Offices and Factory

NEW YORK ELKHART, IND. CHICAGO- -HERBERT H. FROST, Inc..160 North La Salle Street, Chicago.

Mail me a copy of your free booklet, "WhatSet Shall I Build?"

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Address

City State

Professional Set Builders!SEND NOW for full size X -Ray, two-

color, Wiring Diagram for Magnaformer9-8-fully described by J. E. Anderson, inDecember 10 issue of Radio World. Theonly set ever constructed that fully livesup to its advertising claims. Every setinstalled, by its superior performance, auto-matically sells many others. Address Ra-diart Laboratories Co., Dept. 69, No. 19South La Salle Street, Chicago, Ill.

Name

Address

SIXTH YEAR

Vol. XIINo. 18

Whole No. 304January 71, 1923

15c per Copy. $6.00 per Year-

RAD 10PEG.U.S.PAT ore

WORLDA Weekly Paper Published bz Hennessy

Radio Publications Corporation, froml'ublication Omen 145 West 45th Street.

NewYork, N. Y.Phone.: BRYant 0558 and 0559

Technical Accuracy Second to None.

[Entered as second-class matter, March, 1922, at the post office at New. York, N. Y., under :\ t March, 18791

The Biasing ResistorFallacy Exposed!

Quality and Amplification Retained withNegligible Difference in Results as Com-pared with the Irreproachable Grid Battery

[The use of a resistor for obtaining grid bias, particularly for the final audiotube, has aroused much ` discussion among radio technicians, the usual findingbeing that the resistor injures quality and amplification because it is common tothe grid and plate circuits. In the following article J. E. Anderson, TechnicalEditor, while showing that the grid battery is an irreproachable method of bias-ing, proves that a resistor may be used instead without more than a negligibledifference in results, if certain precautions are taken. He also presents for thefirst time his original connections for a humless B supply, conceived on or priorto December 30, 1927, and which is the subject of a patent application.-Editord

VVHY is it that persons will challengethe accuracy of a statement that

merely calls attention to an obvious fact?Why is it that persons get astonishedwhen they witness a demonstration of aphenomenon that acts according to ex-pectations? Why is it that some personsare still doubtful after their attention hasbeen directed to the obvious fact andafter a striking demonstration of it hasbeen staged?

Mental habit, conservatism, excessivefaith in established custom-these aresome of the reasons. In some cases thereluctance to accept a new suggestion,obviously true though it may be, is dueto the common error that the great ma-jority is assumed to be right. Many anew-born idea has been smothered for awhile in the ridicule of the unthinkingmajority. But ultimately the truth willforce itself into general acceptance.

So it will be with the idea that thegrid bias resistor must be detrimentalrather than helpful to quality and ampli-fication. A greater blunder was neverperpetrated in radio than that whichbrought us the grid bias resistor.

Error in High PlacesThe error was not committed originally

by a lowly disciple of the great mastersin radio science, but it had its birth inthe stronghold of the masters themselves.It must have been one of them that firstcommitteed the error, and it must havebeen condoned by many of them, or itnever would have found wide distribution.

The whole thing was built on a fallacy.It started logically enough but it degen-erated into a case of reductio ad ab-

By J. E. AldersonTechnical Editor

surdum, except that not many have yetseen the absurdity of it.

The grid bias resistor came into beingin this wise. Batteries must be doneaway with. Let us start with the gridbattery. All we have to do is to put aresistor in the negative leg of the fila-ment and connect the grid return leadto the negative end. Simple enough and

5.

effective I This expedient introduced thedetrimental effect whereof we shall speaklater, but introduced it only to a neg-ligible extent. Its effect was scarcelymeasurable, much less a major cause fordistortion.

The reason this introduces a negligibleadverse effect is that the bias obtained isdue mainly to the filament current which

C2O

OMOM our- ENEUM PUT

C3

XE

C4

C

f CS

D E

VVVVVVVVVR

/N -PUT0

FIG. IDIAGRAM ILLUSTRATING THE PROPER WAY OF CONNECTING THE BY-PASS CONDENSERS IN A B SUPPLY SO THAT THE LEAST HUM ANDDISTORTION WILL RESULT FROM THE USE OF A GRID BIAS RESISTORIN THE POWER TUBE.

4 RADIO WORLD January 21, 1928

C2MIN

M F

C3

IMO

Cs

C6

FIG. 2DIAGRAM OF A B BATTERY ELIMINATOR INCORPORATING THE BY-PASS

PRINCIPLES DISCUSSED IN CONNECTION WITH FIG. 1.flows through the bias resistor. The platecurrent component is negligible in com-parison with the filament current, and itis the plate current that does the damage.

A variation of this theme was intro-duced when circuits with series connectedfilaments were devised. In these the volt-age drops in the various, filaments wereused to supply the bias for other tubes.In principle this does not differ from thepreceding case. It is simply a more eco-nomical arrangement. The detrimentaleffects on the signal are still negligibleexcept in direct coupled circuits. In thesethe adverse effects usually become majorcontributions to the misbehavior of thecircuit.

Enter the B SupplyThen B battery substitutes were intro-

duced. Higher plate voltages becamecommon, and these required higher gridbias voltages than could be obtained bythe drop in the filament circuit ballast.And then someone reasoned fallaciouslythat the plate current is mostly DC andif that be put through a resistor therewill be a steady drop in the resistor. Itmay be possible to arrange the circuitso that this drop can be used as grid biasfor one or more tubes.

A way was quickly found.But the solution required that the re-

sistor be both in the plate and the gridcircuits at the same time. That is, theresistance was a coupler between theplate and the grid. In some connectionsa single tube was involved. In othercases the coupling extended to all of thetubes in the circuit.

The fallacy in the argument enterswhen it is assumed that the voltage dropin the grid bias resistor is steady. It isfar from steady, but fluctuates widely asthe signal fluctuates. The grid of thetube thus is given a variable grid bias,which amounts to another input voltagethat adds to or subtracts from the signalinput voltage. And since it depends onthe signal voltage the effect is either toreduce or to increase the amplification.

Case AnalyzedWhen a single tube is involved the

amplification is decreased, and theamount of decrease depends on the typeof tube, on the value of the grid biasresistor, on the load on the tube and onthe frequency of the impressed voltage.When two or more tubes are involvedand share the same grid bias resistor theeffect may be an increase or a decreasein the amplification.

In Fig. 1 is given a diagram of a typi-cal B battery eliminator and attached

power tube. The first two choke coils tothe left are the regular eliminator chokesand the third is the speaker couplerchoke. Condenser C3 is the final andlargest condenser in the filter circuit. C4is the stopping condenser which preventsany of the direct plate current fromflowing through the speaker.

The resistance R is the main objectof discussion. It has been put there togive the grid of the power tube a steadygrid bias. But it does not do that; itgives the grid a "wobbulating" grid bias.Suppose we consider an instant when thesignal voltage is increasing. The platecurrent in the power tube is also increas-ing, and this is indicated by arrow A (topright). The corresponding current inother portions of the circuit is indicatedby the other arrows (B, C, D, E).

When Two Are AlikeLet us assume that the filtration is so

thorough that no portion of the signalcurrent flows through the filter chokesbut that all flows through condenser C3.Then current B is the same as current A.This current is divided between the thirdchoke and the loudspeaker in a ratiodepending on the frequency and the im-pedances of the two paths. In a cor-rectly designed amplifier only a negligibleamount flows through the choke andpractically all flows through the speaker.

Current D in the center lead to thefilament heating transformer is also equalto A and B. Between B and D the cur-rent divides between C5 and R (lowerright), the high frequencies tending togo by way of the condenser. Now ifC5 is absent or is very small, current Ethrough R is equal to current D, and anyvariation in E will cause a variable dropacross R.

By tracing out the grid circuit of thetube it will be seen that R is in that cir-cuit as well as in the plate circuit. Thegrid circuit is from the grid to the mid-point on the filament, or to the midtapon the filament transformer. Thus ifthere are any current fluctuations in Rthere will also be voltage fluctuations onthe grid. Since a signal voltage put onthe grid will cause the plate current tovary, and as E is the major part of theplate current fluctuation, the voltage putinto the grid will be reflected, or fedback, to the grid circuit.

Effect CalculatedThe quantitative effect that this feed-

back has on the signal in a typical casecan be calculated very easily. If A is theamplification constant of the tube, R theresistance used for grid bias, r the in-

ternal resistance of the tube, and R2 theresistance of the load on the tube, thereduction in the amplification as compar-ed to the case when R is zero is given by

r+R.

r+R.2-1-R (A+1)

assuming C5 to be zero. In a -71 typetube r equals 2,000, R equals 2,000, Aequals 3 and R2 may be taken as 4,000ohms. When these are substituted in theabove formula we get .43 as the reduc-tion ratio. That is, the voluine is reducedto less than j/Z what it would be with abattery for grid bias.

Suppose that the load resistance is only2,000 ohms, which is more nearly like theactual value for the low notes. The re-duction ratio then becomes .333, or thevolume is only a third as strong as itwould be with batteries for grid bias in-stead of the resistor R.

On Way to UnityNow let us assume that C5 be given a

value of 10 mfd. with the other constantsremaining the same as in the precedingcase. That is, R2 is equal to 2,000 ohms.Let us see how a frequency of 25 cyclesfares. Substitution in the formula showsthat the reduction ratio at this frequencyis .65. At a frequency of 100 cycles thereduction ratio is .84 and for higher fre-quencies still more nearly unity.

When C5 is not used across the gridbias resistor R, all the notes are sup-pressed about the same, and the suppres-sion may amount to the gain in a stageof amplification. When C5 is of smallvalue, say 1 mfd., the high notes will notbe suppressed because they go throughthe condenser instead of through the re-sistor. As the capacity of the condenseris increased, more and more of the signalcurrent will pass through the condenser'and less through the resistor. And asthe capacity is increased the amplifica-tion at any given frequency will increasetoward normal value, that is, the valuethat would be obtained when a grid biasbattery is used. When the capacity isabout 10 mfd. it may be said that thereis no appreciable suppression at a fre-quency of about 30 cycles. Of course thelarger the condenser is, the more nearlyis the reduction ratio unity and the morenearly does the quality of the output re-semble that obtained with a grid biasbattery.

Another ConnectionSuppose condensers Cl, C2 and C3

were connected to the midtap of the fila-ment transformer instead of to the mid -tap of the high voltage transformer, thenpractically none of the signal currentwould flow through R but the steadyplate current would. Hence R would notcause any appreciable reduction in theamplification even if C5 were not used.One might jump at the conclusion thatthat is a simple solution of the difficulty.But it is not.

When the three filter condensers are soconnected the hum from the rectifierpasses through R. This will cause agreater variation in the grid bias thanwas caused by the plate current flowingthrough R. And it will be of a frequency ,

which is very objectionable when mixedwith the signal. The circuit will humbadly but the volume will be high.

This hum may be reduced with con-denser C5 just as the amplification wasincreased with C5. The hum now willnever be lower than 60 cycles per second,and most of it will be 120 cycles per sec-ond. Hence it will be easier to eliminatethe hum than to bring up the amplifica-tion on the lowest audible notes. Sup-pose we connect a 4 mfd. condenseracross R and assume that all the hum isof 120 cycles. If R is 2,000 ohms the im-pedance of the resistor and the con-denser will be reduced to about 1/7 thevalue of the resistor alone. The hum will

January 21, 1928 RADIO WORLD 5

be suppressed in the same ratio. Thatis, 4 mfd. condenser will almost suppressthe hum below audibility.

A Better Way

But there is a still better connection.Suppose condensers Cl and a be leftwhere they are in the diagram. Nowmost of the hum in the eliminator willgo through Cl. That will pass directlyto the return side of the rectifier with-out touching R. Very little of the humreaches C2, but that which does alsoavoids R and goes directly to the rec-tifier. In C3 there is practically no humbecause of the two previous condensersand the two choke coils. Then if we con-nect C3 to the midtap of the filamenttransformer there will be practically nohum passing through R, since only thatwhich reaches 0 will pass through it.It should make very little difference thenwhether C5 is retained or not as far asthe hum is concerned.

What effect will R now have on theamplification? Practically no effect.None of the signal current in the powertube passes through it and hence therewill be no variable voltage drop in it.C3 is so large that nearly all the signalcurrent passes through it directly to themidtap of the filament transformer. Ex-tremely little of the signal current willpass through the chokes and the firsttwo by-pass condensers and so find itsway through R.

Even from this point of view C5 is notabsolutely necessary in theory when thisparticular connection is used. But if itis used it can only aid in the proper op-eration of the set, and the larger itscapacity, the greater its aid will be.

The connection which gives the leasthum and at the same time the least re-duction in the amplification as a resultof the use of the grid bias resistor Ris shown in Fig. 1 by the dotted line.The connection of 0 at the junction Xis removed and the lead brought down tothe midtap on the filament transformer.

Eliminator Described

Fig. 2 depicts an eliminator which in-corporates the principles discussed above.The power tube with its coupler has beenremoved and a voltage divider sub-stituted. The power tube filament trans-former, however, has been retained andthe proper connections have been in-dicated.

The power tube choke and one loud-speaker terminal should be connected tothe 180 volt tap on the voltage dividerstrap. The midtap MF on the heatingtransformer should be connected to theMF terminal on the voltage divider togive the last tube an appropriate biasby means of resistance R5.

The by-pass condensers C6, C7 andC8 are not returned to the same point ascondenser 0 because the tubes whichwill make use of the lower voltage tapswill not get their grid bias from the re-sistor R5. The condensers are returnedto the point to which the negative endsof the filaments of the other tubes willbe connected.

Since the drop in resistance R5 will besubtracted from the effective voltage onthe plate of the last tube, the pointmarked 180 volts should not measure 180volts between zero or B minus but itshould measure 180 plus the grid bias.That is, if the plate voltage is to be 180volts and the grid voltage necessary is40 volts, the voltage between B minusand the 180 volt tap should be 220 volts.

It will be observed that a condenserblock cannot be used for supplying allthe capacities in this power source. Thereason for this is that in the condenserblocks all the condensers are connectedon one side. In this eliminator C3 is in -

INPUT

FIG. 3THE SCHEMATIC DIAGRAM OF A COMPLETE ELIMINATOR AND ONEAMPLIFIER IN WHICH NEW AND IMPROVED CONNECTIONS ARE USED.

dependent of the others on both sides.But a regular block can be used forCl, C2, 0, C6, C7 and C8. A separatecondenser is necessary for C3. C5 maywell be the condenser which ordinarilywould have been used in the 0 position,that is, the otherwise unused capacity inthe block.

The capacities for the various con-densers called for in the diagram Fig. 2should not be less than the following:Cl and C2, each 4 mfd.; 0, 8 mfd.; 0,4 mfd.; C6, C7, CS, each 2 mfd.

Condensers Cl, C2 and 0 should standa continuous voltage of at least 600 voltsand the rest need not be designed forhigher voltages than 300 volts.

Choke coils Ll and I.2 should have in-ductance on full DC load of at least 30henrys each, and the resistance of eachshould not be greater than about 400ohms.

R1 should be a variable resistor witha range of from zero to 10,000 ohms andit should be able to carry continuouslyat least 25 milliamperes. R5 should bea variable resistor with a range of zeroto 2,000 ohms.

By the addition of one separate con-denser almost any B supply can easily bechanged over.

R5 should be a variable resistor with arange of zero to 2,000 ohms.

By the addition of one separate conden-ser almost any B supply can easily bechanged over.

Speaker Connection

In the circuit arrangement shown inFig. 1 the loudspeaker is connected acrossthe output choke coil alone. The signalcurrent therefore must go through 0 be-fore it can complete its circuit, or else itmust find a way back through the rectifierand the filter. Obviously, a large currentwill flow by way of the choke coils andthe rectifier when the speaker is con-nected as in Fig. 1 then if the speakerreturn were connected on the low side ofC3. The proper way to connect the re-producer is that which sends the leastsignal current through the rectifier andthe filter, as well as the least through theresistor R.

The speaker connection shown in Fig. 1is the usual connection because this is themost convenient in most cases and it alsosubjects the stopping condenser C4 to alow stress. But it is not the best from theviewpoint of quality of reproduction,degree of amplification, and stability of thecircuit. Fig. 3 shows the connectionswhich will introduce the least hum in thesignal, which will yield the greatest stabil-ity of the circuit, and which will operatewith the least dependance on the resistorR.

The Reversal in Fig. 3

Note also in Fig. 3 that the positions ofthe speaker and the stopping condenserhave been reversed. The speaker is next

to the tube and the condenser is belowit. This arrangement has been made sothat the condenser C4 may be combined ina condenser block more easily.

It will 132 observed that condensers 0,C4 and C5 have one side in common sothat they can be housed in one block ifthat is convenient. All of these should belarge, say 4 mfd. or more, and C3 andC4 must stand the full voltage of theeliminator.

C5 can be combined also with the othercondensers, since it has one side in com-mon with Cl. C2, C6, C7 and 0. Thefirst of these, or Cl and C2, must be de-signed to stand the highest workingvoltage.

In many cases it is preferable to omitcondensers C6, C7 and a from theeliminator and to put them in the receiver,if needed. There are many good reasonswhy they should not be put in the elimin-ator. In many circuits taps 6, 7 and 8will not be used at all. In such cases thecondensers will be It would awaste of money and space to use them.In other cases it is necessary to use by-pass condensers in the set in order to by-pass the leads to the eliminator. Theduplication caused by using C6, C7, andC8 as well is unnecessary, and the con-densers in the set are enough. Often theyneed not be more than .01 mfd. to servethe purpose.

Condensers PreferredWhen building an eliminator like the

one described above it should be remem-bered that it is better to use condensersfor removing hum than to use induct-ances for this purpose.

Both inductance and capacity are neces-sary to remove the hum effectively, butfor a given degree of residual hum thefiltering will remain the same if the con-densers are doubled in capacity and ifthe inductances are halved.

The eliminator will cost more if thefiltering is done with small coils andlarge condensers, but it will give verymuch better service. It is a great mis-take to try to save on the condensers.

Condensers across the line suitablydecrease the effective AC resistance ofthe filter whether it is measured fromthe rectifier or from the receiver. Coilshave the opposite effect. Not only dothey increase the direct current resist-ance but they also greatly increase ACresistance.

On high frequencies, say from 5,000 up-ward, the by-pass condensers ordinarilyused are very effective and the resist-ance of the filter measured from the re-ceiver is negligible But for low fre-quencies, particularly sub -audible frequen-cies, the condensers are ineffectual andthe resistance of the filter is that of thecoils and the rectifier in series.

* * *

This concludes the theretical discussion ofJ. E. Anderson's original method of de-signing A B supply. Constructional datawill be published next week.

6 RADIO WORLD January 21, 1928

The Shielded Grid Six

THE audio amplifier frequency char-acteristic is flat from about 30 cycles

to above 5,000 cycles, thus giving distor-tionless amplification. Ahove 5,000 cyclesthe amplifier cuts off to reduce the all tooprevalent "background noise" and hetero-dyne squeals uncontrolled under presentcongested broadcast conditions.

The voltage amplificaiton of the audioamplifier, with 112 or 112A power tubes,is about 400 to 450 times. The 221 out-put transformer protects loudspeakerwindings and compensates for averagepoor speaker bass note performance.

Both models are assembled on a formed

[The Shielded Grid Six began in the Jan-uary 7 issue, was continued in the January14 issue, and is concluded herewith, This isthe first national presentation of a tunedradio frequency receiver using the new andpowerful radio amplifying tubes.]

By McMurdo Silver

PART III

end of the 3,800 ohm resistance may con-nect to the plus 90 post of the power unit,and the remaining end of the 5,500 ohmsection may connect to the plus AMPpost of the power unit-a Ward -Leonardtype 659 resistor may be used satisfactorilyfor this purpose, the resistor being placedat some point near the power unit. Onepower unit, not equipped with glow tuberegulator, but with fixed B voltage tapsof sufficient accuracy for operation of the630 -SG, is the S -M type 675, which, inci-dentally, also supplies enough B powerso that a 210 tube may be used in the lastaudio stage of the receiver to which this

, ' I

Z'24i

THE ANTENNA MODEL SHIELDED GRID SIX, AS SEEN FROM THE IN-PUT END, WITH TERMINAL STRIP IN LOWER FOREGROUND, ONESHIELD BEING REMOVED TO SHOW DETAIL OF THE COIL -CONDENSER

INSTALLATION.

metal chassis 12 inches deep, 19% incheslong and 1% inches high, with beautifullydecorated bronze control panel carryingtwo vernier tuning dials, volume control,on -off switch, and antenna switch.

Advice on B EliminatorIf a B eliminator is used with the re-

ceiver, it is very important that it beonly of the glow tub'e regulated, fixedvoltage type, for it is necessary that thevalues of 45 and 135 volts required for thereceiver B circuit be accurate to within10 to 15 per cent-an accuracy which isabsolutely impossible to obtain by guess-work with standard B eliminator equippedwith variable voltage controls. Such elim-inators may be used with the receiver onlywhen preliminary adjustment of their out-put voltage may be made with a goodhigh -resistance voltmeter.

The S -M 652 or 652A types are theonly glow -tube -equipped power units nowon the market, and one of these shouldhe employed. The B minus, plus 45 andplus AMP posts should be connected tothe similarly marked posts of the powerunit. The plus 135 post of the receivermust be connected to one end of a 3,800ohm resistance, as well as to one end ofa 5,500 ohm resistance. The remaining

power unit will furnish A, B and G power,as well as B power to the rest of the re-ceiver.

Simple to Operate

The operation of the receiver is simple.Turn it on with an On -Off switch, adjustthe volume knob to the maximum or fullright position and tune in stations whichwill he received with the two dials rotat-ing approximately alike. Volume may beregulated with the volume knob and acoarse regulation of the selectivity selec-tor I dial effected by throwing the an-tenna short and long switch from shortto long position and vice versa.

For a Residential DistrictIf the set is to be operated in a resi-

dential district three or four miles froma local broadcast station, the plate leadsof the RF amplifier tubes should be fas-tened under terminal screws No. 2 of theB, C and D coil sockets, which is the posi-tion of greatest volume together with ex-tremely good selectivity.

Moving the three plate leads to post 4of the respective coil sockets increases theselectivity and decreases the volume veryslightly. While connecting the plate leadsto post 1 of the B, C and D coil sockets

gives an extremely high value of selectiv-ity at the expense of a slight decrease involume, this connection is recommendedonly where the receiver is located withinhalf a mile or a mile of a broadcastingstation.

Recommended ConnectionThe three condensers in the B, C and

D stage compartments should be gangedby fastening the link motion in them andadjusting it so that all three condensersbegin to interleave and hit their stoprods at the same time. After the set hasbeen in operation, the antenna lengthshould be cut down until some station atabout 300 or 325 meters is barely audible.The right-hand condenser should then beloosened from the ganging and tuned in-dividually.

While the B and C condensers are tunedtogether for loudest signal, the conditionof loudest signal will be when the D con-denser lags slightly behind the B and Ccondensers, and the link motion shouldhe tightly locked in place at this pointafter which no attention need be paid toganging.

Will Not OscillateIn operating the 630 -SG receiver, re-

member that it tunes exactly like anyordinary neutrodyne or non -oscillatingtuned RF receiver and that it will notoscillate if properly assembled (except inthe case of very unusual operating con-ditions where it may oscillate with theplate leads connected to post 2 of the "B,""C" and "D" coil sockets, and with noantenna connected to the receiver.) Witheven a 15 foot antenna connected, the setwill not oscillate at any wavelength.

The set in operation should give loudspeaker signals upon stations barely aud-ible upon other tuned RF or superheter-odyne receivers, or it should give equiva-lent volume with far greater selectivity onany stations that may be heard with anystandard tuned RF receiver operating ona 60 to 100 foot antenna, the ShieldedGrid receiver for this test being equippedonly with a 10 to 15 foot length of wirefor an antenna. So operated, it will pro-vide superheterodyne selectivity, surpris-ing simplicity of operation, and volumeequal or greater than that obtainablefrom standard tuned RF and ordinarysuperheterodyne receivers.

Air Waves RegulateCity's Water Pressure

Marion, Ind.Signals transmitted by radio regulate

the pressure of the city water supply.The transmitting apparatus, located at

the office of the Mario Water Company,which controls the water supply, is threemiles from the plant. Every half hour,for two -minute periods, the transmitterautomatically sends out regulating codesignals, which are picked up by an em-ployee at the plant. The wavelengths ofthe signals correspond to the water pres-sure. The code signal sounds when thepointer on the dial is at its proper spot.

January 21, 1928 RADIO WORLD 7

How to Banish BuzzesD°

you hear buzzing notes in yourreceiver which are always coincident

with certain notes? For example, doesyour speaker emit a sound like a trappedfly every time the note "E" is sounded?If you do hear this buzzing somethingis loose about your receiver. It may bean integral part of the receiver itself orit may be some object near the repro-ducer. There may be a screw loose inthe speaker itself which rattles when asound of a certain pitch is struck. Theremay a bit of paper about the cone whichhas shaken loose. There may be a. littlebutton lying somewhere near the speak-er. There may be a loose lamina in thecore of one of the transformers or chokesin the receiver.

These are just a few of the possiblecauses of the buzz. There are countlessplaces where the buzz may enter.

Another source of the buzzing is strik-ing of the pole pieces by the armature inthe loudspeaker. This occurs when thereis audio regeneration on certain notes.These regenerative peaks in the amplifi-cation may occur at any point in thescale. Whenever they occur they soundlike bzzzzz.

Step by Step EliminationIt is often extremely difficult to locate

the source of the buzz, particularly whenit is caused by something loose about theset,. The best way of going about findingthe source is progressive elimination.

Suppose there is something free to buzzin the room in which the loudspeaker isworking, but not an integral part of thespeaker itself. A pair of long leads canbe connected to the reproducer so thatit can be taken to another room. Closethe door to the room in which it was be-fore. Does the buzz persist? If it does,the first room probably does not containthe source of the buzz independently ofthe receiver. If the buzz stops when theloudspeaker is carried to another room,the source is probably in the first room.If that is the case place the speaker inseveral different positions in the roomand note the intensity in the buzzing. Itshould increase as the speaker gets nearerthe loose object.

If the speaker itself is suspected ofentertaining the loose object, substituteanother speaker, and carry the old speak-er out of the room while testing. If thefirst speaker is found to contain the buzz-er, investigate it externally to see thatthere is nothing loose. If all is well onthe exterior, open up the speaker andcheck over the inside. Tighten all thescrews and note particularly that thereis no dust between the armature and thepole pieces. See that there are no loosebits of paper or other light objects inthe cone or driving unit.

Testing the EliminatorIt is possible that the eliminator, if

one is used, is the cause of the buzzing.The substitution of another eliminator ora battery will either convict or absolvethe eliminator. Make this test, if possi-ble.

Perhaps a little exploration with the earwill locate the trouble. If the buzzingsound originates from something loose onthe exterior of the receiver or in theroom, it should be possible to locate itjust as the source of any other sound is

By Capt. Peter V O'RourkeContributing Editor

.00/ /Y/F0.4,-.0.5 MEG.

.00025 0F0.OA_

CIRCUIT DIAGRAM SHOWING HOW AN AUXILIARY OSCILLATOR CAN BEMADE AND CONNNECTED TO AN OSCILLATING DETECTOR IN A RE-CEIVER FOR GENERATING AN AUDIO FREQUENCY BEAT FOR BUZZING

TESTS.

DETECTOR //), SET

1 -----TO .910-

coup SP?rkL/FieR ..9

45

OA

located. But if the buzz has its origininside the set, or inside a transformer orchoke, it cannot be located this way. Thesubstitution method will usually locatethe trouble whether it is of internal orexternal origin. Even if it is of regenera-tive origin this will aid in the search.

If the buzzing is due to regenerationand a high amplification peak and conse-quent striking of the pole pieces thetrouble should disappear if the volumeis turned down to the point where thearmature will no longer strike even onthe volume peaks. If the buzz is causedby something loose in or about the setthis test will not remove the noise. Itwill persist even on low volume but itwill be less marked on account of the lessintense agitation to which the loose ob-ject is subjected.

In tracing down the source of a paras-itic noise like this nothing at all shouldbe taken for granted. For example, itshould not be assumed that the windowpane or the receiver panel are innocent.The rule should be that all are guiltyuntil proved innocent. In one case ofthis kind the noise was traced to a thinwooden panel lying on top of a cupboardwhich was standing at a considerable dis-tance from the loudspeaker or the set.

Resonance the General CauseThe buzzing noise is generally caused

by resonance, electrical or acoustical.Everything in the room has a certainnatural frequency of vibration, which ismore or less pronounced. When the loud-speaker sounds a note of the same pitchas the natural frequency of an object,and holds it a moment, the object is setinto sympathetic vibration. The buzzfollows when the vibrating body strikessomething. When the source of thebuzzing is electrical it is usually electri-cal resonance which gives rise to theamplification peak, and the buzz followswhen the armature strikes the polepieces.

When hunting for the source of a buzzit is not practical always to depend on thesignal to give the required note. It is

best to have a local audio frequency os-cillator which can be set at will to thenote at which the buzzing is most severe.The most convenient audio frequency os-cillator having a continuously variablefrequency is a beat note oscillator. Inthis the desired audible frequency is ob-tained by beating two high frequenciesand detecting the beat note and ampli-fying it. The audio frequency is variedby varying the frequency of one of thehigh frequency oscillator.

If the receiver has a regenerative de-tector this can be used as one of the highfrequency oscillators. It is only neces-sary to hook up a simple oscillator andcouple it to the detector. just placingthe oscillator coil of the second oscillatornear the regenerative coil of the detec-tor is enough to couple the two.

A Considerate WayWhen the detector is used as one of

the oscillators, the antenna and groundleads should be disconnected so that thesqueals resulting will not be radiated todisturb the neighbors. This test shouldalso be carried out at a time when fewpeople would be tuned in on any sta-tion.

Again the detector and the auxiliaryoscillators could be set so that the radi-ated frequency, if any, is out of thebroadcast band. For example, the oscil-lator condenser could be set at maximumand the condenser of the auxiliary oscil-lator could be increased when changingthe beat note from zero to the desiredvalue. This would insure that the twobeating frequencies were always belowthe broadcast frequencies.

HEAR WRNY ON 30.9 METERSThe programs of WRNY, which are

heard on 325.9 meters, may also be lis-tened to on 30.9 meters through 2XAL.On Tuesday the station is on from 7 to12 P. M.; on Wednesday, from 7 to 9P. M.; on Friday, from 7 to 11 P. M.; onSaturday from 7 to 10 P. M., and on Sun-day from 4 to 6 P. M.

8 RADIO WORLD January 21, 1928

Radio UniversityWhen writing for information give your Radio

AFREE Question and An-swer Department con-

ducted by RADIO WORLDfor its yearly subscribersonly by its staff of Experts.Address Radio University,RADIO WORLD, 145 West45th St., New York City.

University subscription number.

°111.02Mt d. 85/

60

PO

4-

0 +e De+

A0 C,0 c

FIG. 594HOW A PHONOGRAPH PICK-UP MAY BE HOOKED IN TO THE SECOND

DETECTOR OF THE VICTOREEN SUPER -HETERODYNE.

I CONSTRUCTED a Victoreen Super -Heterodyne from the data which ap-peared in September 3, 10, 17 and 24 is-sues of RADIO WORLD. The results arewonderful. Is it possible to wire, up thisset, so that a phonograph pickup can beemployed? If this is so, please show thewiring diagram. GEORGE DEACON,N. Y. City.

Yes, a pickup can be used very suc-cessfully on the Victoreen Super -Hetero-dyne, using the Victoreen 112 audio trans-formers. How to connect it is shown inFig. 594. An extra pair of binding postsare mounted at the rear of the baseboard.From one post, which can be labelled B,run a lead to a switch (filament switchtype). The other side of the switch isthen connected to the G post on thesecond detector tube socket. Procure a.02 mfd. fixed condenser and run a leadfrom this condenser to the B post. Theother terminal of the condenser is thenconnected to the binding post, which canbe labelled A. This post is, in turn, con-nected to the A plus post. The pickupis inserted across the posts A and B. Touse, simply snap on the Switch Sl. Itcan be seen that the pick is insertedacross the grid and plus A terminals.

* * *

IN MY 6 -tube receiver, which consistsof two stages of tuned radio and a de-tector, all ganged to a drum control, andthree stages of double impedance coupledaudio, I wish to install a choke coil andcondenser at the output. I have a 100henry choke and a 8 mfd. fixed conden-ser with a 600 volt DC breakdown guar-antee. Could these both be used? Iunderstand that the choke coil is con-nected between the plate and the B pluspost. Also that one terminal of the con-denser is brought to the post of the lasttube and one terminal is brought to thespeaker post, the other speaker post be-ing brought to the minus A post. Is thiscorrect?-L. P. BUNER, Tacoma, Wash.

Yes, you can use these parts. Yourwiring data are correct. You can checkthis up and be more certain of it by re-ferring to the diagram which appeared onpage 18 in the Radio University columns,in the November 5, 1927 issue of RADIOWORLD.

* * *I RECENTLY saw a circuit diagram

of a 4 -tube receiver, in which the 3 -cir-cuit tuner was incorporated in the radiofrequency stage. The detector was non -regenerative, while the audio was trans-former coupled. Now isn't this circuit

fundamentally similar to the Superdynewhich was described several years ago?I had an argument with a friend of mineabout this and therefore wish to get thematter cleared up.

(2)-Another thing I would like to knowis, if a 3 -circuit tuner is used, with .0005mfd. variable condensers in the input, willit be possible to use a loop also?-JOHNROFERS, Beverly Hills, Calif.

(1)-Yes.(2)-Yes, but you will not be able to

obtain benefit of the tuner. To do this,you will have to build a special coil.Procure a 3 inch diameter tubing, 6inches long; a tubing 1g inches in diame-ter and 2 inches long, and some No. 22double cotton covered wire, as well asNo. 26 single silk covered wire. Wind 10turns on the larger tubings. This is forthe primary. Skip a quarter of an inchand wind 50 turns, this for the secondary.Again skip a quarter of an inch, andwind 12 turns. The tickler is wound onthe smaller form, and consists of 36turns, using the smaller sized wire. The 22wire is used for the windings on the largertubing. The primary and secondary areconnected up in the standard way. Whenit is desired to use the loop, the loop isshunted across the variable condenser andthe secondary leads detached from thispoint. The extra winding is brought intouse, here. It is connected between thestationary plate post of the variable con-denser and the grid post of the socket.These connections can remain, when us-ing the antenna ground, also.

* * *

I HAVE all the material necessary toconstruct the one -dial receiver describedin the Feb. 5 issue of RADIO WORLD, onpages 8 and 9. I would like to knowwhether it would be feasible to add atube using just a tube and a 1000 ohmfixed resistor before the first radio fre-quency amplifier, in the same fashion asemployed in the Aero-Seven, which wasdescribed in the October 8, 15 and 22 is-sues of RADIO WORLD.

(2)-Could I use an Amperite to con-trol the filament?-RAYMOND TRAIN,Marsteller, Pa.

(1)-Yes, this will work out all right.(2)-Yes.

*. * *

WHAT COULD be done to make mydetector tube, with a variometer in theplate circuit, oscillate more readily?

(2)-Does it matter in which lead afilament switch is placed?

(3)-In my present receiver there are

two transformer coupled audio stages,using three to one ratio transformers.Could I add another audio stage? If so,what ratio transformer would it be ad-visable to use?

(4)-Would I get better results if Iconnected the plate circuits of the de-tector and two audio tube plates to sepa-rate B plus posts? If so, what voltagewould you suggest applying? Am using-01A tubes.-ELLIOT H. KILSTAR,Hollywood, Calif.

(1)-Insert a 1 mfd. condenser fromB4- detector in the set to detector fila-ment minus. Increase the detector platevoltage.

(2)-No.(3)-No, it would not be advisable to

add any more audio.(4)-Just keep the detector plate volt-

age separate. Use from 45 to 67% voltshere. Use 135 volts on the audio plates,with a 4% volt C bias in the grid circuitof the first audio tube, and a 9 volt Cbias in the grid circuit of the secondaudio tube.

* * *

I AM going to build a 4 -tube non -re-generative receiver and would like to getsome information before going ahead.

(1)-Is it all right to place the lA Am-perites, of which there will be four, onein each filament leg, very close to eachother?

(2)-I wish to use a loop with a .0005mfd. variable condenser across it. Willyou please give me the correct numberof turns, size of form and kind of wire,necessary to build the loop? Also statehow far apart the windings should beplaced.-HARRY MILTON, Newark, N.J.

(1)-Yes.(2)-Get a 2 foot square form and some

No. 18 annunciator wire. Spacing eachturn one -quarter inch, wind 14 turns.

* * *

I RECENTLY obtained a circuit dia-gram of a 3 -tube reflex, designed for usewith -99 type tubes, as well as obtain-ing a loop. There are a tuned reflexedradio frequency stage, a regenerative de-tector (using a 3 -circuit tuner) and astage of transformer coupled audio. Allthe filaments are rheostat controlled.The grid returns of the radio frequencyand the first audio tube are brought to aminus C 4% volt post. Now, I would liketo use this receiver on the -01A typetubes. Are there any changes to make?Each B plus lead is by-passed with a 1mfd. fixed condenser, to the minus A post.

(2)-Across the secondary winding ofthe transformer in the audio stage, (notreflexed) a 200,000 ohm variable resist-ance is shunted. Is this a volume con-trol?-WILLIAM STRENTER, Provi-dence, R. I.

(1)-No changes will be necessary, ex-cept to use a 6 -volt source for the fila-ments. The -014- tubes stand a higherplate voltage. To the radio frequencyplate, apply 67%; to the detector plates,apply 45 volts, while to the first audio,you can apply 135 volts. It will be ad-visable to use separate C batteries; 3volts for the radio, and 9 volts for the au-dio.

* *

IN THE OCTOBER issue of RADIOWORLD a B eliminator to be used on di-rect current was described. I have con-structed this device, using all the specifiedparts, which were tested before inserting,but cannot get good results. Will yoube kind enough to enlighten me as towhere I have erred, or if there are anyerrors in the diagram?-ALEXANDERH. FORMAN, Philadelphia, Pa.

You may have forgotten to connectthe minus B to the plus A post. This con-nection was left out of the diagram be-cause they are already connected to-gether in most sets.

January 21, 1928 RADIO WORLD 9OUR CLUB wishes to build a 3 -stage

audio amplifier, using the following parts:A 3 to 1 ratio audio transformer; three

2 to 1 ratio audio transformers with pri-maries burned out; two .1 mfd. fixed con-densers; a 500,000 ohm fixed resistor; afilament switch; two 1 A Amperites ; one112 Amperite; two -01A tubes, and one171 tube. Please show the circuit dia-gram of such an amplifier.-GIMBALSTEWART, Concord, Calif.

See Fig. 595 for the circuit diagram.The transformer which is 0. K. is usedin the first stage of coupling. The sec-ondary of one of the burned -out trans-formers is used in the plate circuit ofthe first tube, this being coupled to the500,000 ohm resistor by a .1 mfd. fixedresistor, to make up the second stage ofaudio. In the third audio stage, both sec-ondary windings are used. The -01Atubes are used in the first and secondstages, while the -71 is used in the laststage. For filament control in the firsttwo stages the lA amperites are used,while in the last stage, the 112 is used.Apply 135 volts to the first two audioplates. For the last plate, use 180 voltsof B. The C bias here is 40% volts. Thespeaker posts should be brought to sometype of a filter, either of the condenser -choke or transforMer type.

* * *

ABOUT SIX months ago I built a five -tube reflexed receiver. I have not hadmuch time to play around with it, untilrecently. I am not satisfied with it. Iwas told that if I did away with the re -flexing portion of the circuit I would getbetter results. The first two tuned radiostages are reflexed. The rest of the cir-cuit is standard, with transformer audio.Is it only necessary to remove the audiotransformers in the tuned radio stages todo away with the reflexing? If this is so,then I suppose you connect the grid re-turns directly to the minus A, insteadof through the secondary windings of theaudio transformers, and the plate of thedetector tube to the plate post of theaudio transformer to the first audio tube.Is this correct?

(2)-Are the terminals which went tothe primaries of the audio transformersbrought to the B plus posts?-TEDWILIT, Adams City, Colo.

(1)-Yes, your results will be better.Your connections are 0. K.

(2)-Yes.* *

I HAVE constructed the audio ampli-fier described by John F. Rider in theSeptember 24 issue of RADIO WORLD and .

am well pleased with it. I used a Beliminator and an A battery. I decidedto make the entire amplifier AC operatedand purchased a transformer to light thefilaments. Upon looking at the diagram,I notice that the transformer has a tappedsecondary while the one I have has justone continuous winding. I would appre-ciate knowing just what must be doneto my transformer so as to get the sameresults as when using the tapped second-ary, or if it is at all necessary.-WIL-FRED HARLEM Pittsfield, Mass.

It is necessary to have a tapped second-ary winding on the transformer, or if thewinding is continuous, as in your case, apotentiometer shunted across the wind-ing, or a center tapped fixed resistance.If a potentiometer is used 200 ohmswould be the maximum. Only 50 ohmsor so would be needed ordinarily.

* * *

I BUILT a 4 -tube receiver consistingof a tuned stage of radio -frequency am-plification, a 3 -circuit tuner -detector andtwo stages of transformer coupled audiofrequency amplification. The set .worksremarkably well on the low waves, butvery poor on the higher waves. I usecoils containing 8 turns on the primaries,and 47 turns on the secondaries. The .0005mfd. variable condensers are employed.One thing I noticed, upon close inspec-

FIG. 595THE THREE STAGE AUDIO AMPLIFIER REQUESTED BY

ART.tion of the coils, which I have not seenon any other coils. That is, the primaryis separated about % inch from the sec-ondary separated by a piece of empirecloth which is A. inch thick. I have seencoils where the primary was wound on topof the secondary and separated by empirecloth, but never this. I did not notice thispreviously, because the coils were en-cased in hard rubber forms. Do you thinkthe trouble could lie here?-HUDSON()SSW Baton Rouge, La.

Yes. Suggest you remove the cloth andplace the primary to within a 5 inch ofthe secondary. Then add about 6 turnsto the primary. If there is no rheostatin the radio frequency filament circuit,insert one. It should have a resistanceof 20 ohms.

* *

I AM going to construct the AC 300receiver described in the December 24and 31 issues of RADIO WORLD, but beforegoing ahead, would like to get some in-formation.

(1)-Can a 210 power tube be used inthe last stage of audio frequency ampli-fication?

(2)-If this tube can be used, is it neces-sary to install a special transformer toheat the filament or can the same 5 voltwinding used for the -71, be employed?

(3)-Are the B minus and the A minusconnections made internally, as the set iswired up?

(4)-I notice that there is no provisionsfor an output device to prevent the speak-er windings from becoming injured.Isn't one necessary? I have a standardoutput transformer. If one is needed,could this be used?-FRANK ELLIOT,Kansas City, Mo,

(1)-Yes.(2)-You will have to use a separate

transformer with a 7.5 volt secondarywinding. Be sure that B supply hassufficient voltage, e.g., 450, for this is thevoltage necessary for the successfuloperation of this tube.

(3)-Yes.(4)-Yes, you can use your output

transformer. The words speaker filter on

GIMBAL STEW -

the diagram refer to such a device, al-though not shown diagrammatically. Justconnect the primary circuit across thetwo posts, between the B plus and plate.The secondary terminals are brought tothe speaker.

* * *WHAT METALS beside aluminum

which will allow the current go one wayand not the other, can be used in a recti-fier cell?

(2) Are there any other metals be-side lead that can be used as the otherelement in the cell?-HARRIS GRADER,Bennet, Colo.

(1) Tungsten, bismuth, magnesium,etc.

(2) Yes, carbon or iron.* * *

USING A 44 inch diameter tubing,please tell me how many turns of No. 26double cotton covered wire must be puton secondary windings, for use with.00025 mfd., .00035mfd., .0005 mfd. and .001mfd. variable condensers.-ALEXANDEROPENTERTEIN, Silvana, Wash.

For the .00025 mfd. condenser, 80 turnsare necessary. For' the .00035 mfd. fixedcondenser, 70 turns are needed. For the.0005 mfd condenser, 45 turns are re-quired, and for the .001 mfd. condenser,use 31 turns.

* * *

WHEN USING No. 22 double cottoncovered wire, how many turns can youput on within one inch?

(2) Can a dry B battery be used witha B eliminator to boost up the voltage?-KENNETH STRATFORD, Loving. Tex.

(1) There are 28 turns to the inch.(2) Yes.

* * *I USE a bakelite A battery charger.

If it is used to charge the battery at thesame time the set is going, I get an an-noying buzz. Can you tell me what de-vice I can employ, as a filter to destroythis noise? A friend of mine told me touse an Abox Filter. Would this work outall right ?-SAM GELTERMAN, Rock-dale, Wis.

Yes.

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10 RADIO WORLD January 21, 1928

$1,000 -a- Minute Progfrom N ation-

Greatest Audience in"Victory Hour" from 47Beverly Hills, Calif.,New York, Fred andDodge Bros. President atOrleans -A Complete

By Herman

THE TRANSCONTINENTAL TELEPHONE LINE THAT CARRIED WILLROGERS' VOICE TO WEAF FOR BROADCASTING BY THAT STATION ANDRETELEPHONING TO THE 46 OTHER STATIONS WAS ROUTED AS SHOWNBY THE HEAVY LINE. THE DASH LINE SHOWS THE EMERGENCYSOUTHERN ROUTE WHICH WOULD HAVE BEEN USED HAD BAD

WEATHER PREVAILED ALONG THE SHORTER COURSE.

44 r'M told I'm talking to 30,000,000 radiolisteners-one of the greatest audi-

ences ever reached by the human voice-more than one -quarter of the entire popu-lation of the United States."

So said E. G. Wilmer, president ofDodge Brothers, Incorporated, during theVictory Hour, recently presented by hiscompany over a network of 47 stations.

Second in importance only to the mag-nitude of the audience was the electrical

and mechanical feat of broadcasting themusic and speech from points on a na-tional quadrangle. But from the popularviewpoint the outstanding feature was thefame and talent of the performers.

Will Rogers, master of ceremonies,spoke from a chair in his home in Bev-erly Hills, a suburb of Los Angeles, Calif.Paul Whiteman and his orchestra playedin a studio of WEAF in New York City.Mr. Wilmer addressed the audience from

Program Required WireLine 30,000 Miles Long

At a cost of over one thousand dollarsa minute, and using 30,000 miles of specialwire -line facilities, the Victory Hour wasconducted successfully. There were threetranscontinental circuits totalling twentythousand miles and a telegraphic com-munication circuit of ten thousand milesin length.

The program was the greatest mechan-ical achievement in radio telephony andthe costliest radio program.

The engineers of the National Broad-casting Company, in conjunction withthose of the Bell System, had been work-ing on the plans for this intricate broad-cast for several weeks. During the de-velopment of these plans many complica-tions arose, particularly with respect tosynchronizing the "switching centers" sowidely separated. Very carefully timedprogram details formed the hasis uponwhich the engineers scheduled their finalarrangements.

The transcontinental line which carriedWill Rogers' introductions was routedto San Francisco, through Salt Lake City,

Denver, Omaha, Chicago and thence toNew York. An emergency circuit washeld in readiness routed from San Fran-cisco to Dallas, Texas, to Little Rock, St.Louis, Chicago and New York. Hadweather conditions been unfavorablealong the northern route, the southernroute would have been used for wiretransmission.

From each "pick-up" point a similararrangement was planned. In all, a totalof 20,000 miles of special telephonic cir-cuits were used to put the program onthe air on a nationwide scale. In addi-tion to the special telephonic circuits,10,000 miles of wire were used for theMorse telegraph circuit which enabledthe engineers at the numerous radio sta-tion, "pick-up" points and telephone "re-peater" stations to carry "switching" or-ders back and forth. Through this Morsewire communication service the engineerswere also kept advised as to weather con-ditions along the routes of the variouscircuits.

The weather was excellent.

his home in Detroit. Fred Stone and hisdaughter, Dorothy, performed before amicrophone in the dressing room of theErlanger Theatre, Chicago, between actsof "Criss Cross," and Al Jolson sangand cracked jokes from his room in theHotel Roosevelt, New Orleans.

The Long RoutesThe program was sent out by WEAF.

This required the transmission from thedistant points by telephone, by so-called"land wires," and the retransmission bythe same method to the 46 other stations.Some of these stations were relativelyclose to one point of origin. Yet a mon-eyed voice at a microphone traveled byland wire to New York and back againbefore being impressed on a radiated radiowave.

Take two instances among the several:Jolson sang in New Orleans, literallylong-distance telephoning to WEAF, NewYork, and WEAF passed the song alongby telephone wire to WSMB for broad-casting. WSMB is located in New Or-leans, yet sent out a song rendered inNew Orleans after it had traveled 4,000miles by land wire. KFI, Los Angeles,sent out Rogers' talk after it had made atranscontinental round trip of more than6,000 miles.

That the performers were great attrac-tions is attested by the fact that a totalof $25,000 was paid to Rogers, Jolson,the Stones and Whiteman. Besides, $35,000 was paid in telephone tolls and for me-chanical work, while the station time-one' hour-cost Dodge Brothers $7,600.Advertising the advance program in news-papers cost several thousands of dollars.

But prices do not tell the story. Thenation cancelled its engagements to listento the Victory Hour. This was the nightof nights when there was no place likehome.

An Outstanding SuccessAll told the hour was a magnificent suc-

cess. It afforded the greatest listener in-terest in the history of radio-probablyin the history of the world-and madeevery owner of a receiver doubly glad ofbeing able to enjoy the constant advan-tages of reception generally, and this pro-gram in particular.

Not that the hour was without its draw-backs. Jolson showed bad taste in telling

1

January 21, 1928 RADTO VI 0 R T_ D 11

ram Reaches 30,000,000wide "Studio"World's History HearsStations - Rogers, fromintroduces Whiteman atDorothy Stone at Chicago,Detroit and Jolson at NewReview of the Program

Bernardtwo "jokes" that were not nice. One as-sociated gin with a little girl and put apicture actress whom Jolson named in anawkward position for any mother-indeedany woman. The other referred in anequivocal way to a person lying in bed.Anybody who heard these "jokes" in thesanctity of his home and with his familyaround him must have felt a pang of re-gret that Jolson for once strayed from thepath that has marked radio programssince the beginning.

Nothing Jolson said was utterly unfitfor repetition, but he did misjudge hisaudience. It would be mere confoundingof a regrettable incident to retell thosetwo "jokes."

Sentimental AssociationThe selection of material for rendition

also suffered somewhat when Whiteman'sorchestra played excerpts from "Rhap-sody in Blue," by George Gershwin, andwhen it played "Among My Souvenirs."Both of these have been overdone on theradio. It even so happened another musi-cal organization had played excerptsfrom "Rhapsody in Blue" over WEAFjust a little while before. Some excusefor lack of distinctiveness of choice ex-isted, Mr. Whiteman evidently thought,in the fact that originally the "Blue"piece was written especially for his or-chestra by Gershwin "four or five yearsago." Mr. Whiteman, who personally an-nounced the numbers, told the audienceabout the association between the compo-sition and orchestra, so there was perhapssentimental and association reason for thisselection, but more freshness might havebeen developed by substituting for"Among My Souvenirs."

Both pieces are highly skillful in com-position and engaging, too, only theyhave been hammered too hard of late tobe entitled to place on a distinctive pro-

gram.Whiteman's orchestra played its string

of pieces with fine, skill and spirit. Thechoice of material was open to criticism.That is no reflection on the rendition.Whiteman is Whiteman, you know.

Technical AspectsTechnically there was some difficulty

obtaining good quality. I listened in atmy home in New York City. When Phil-

4Nr.

0O

8

OND7

THIS RADIO AMPLIFIER AND ONE STAGE OF AUDIO, FOLLOWED BY ATRANSFORMER COUPLED AUDIO STAGE BUILT INTO THE B SUPPLY,CONSTITUTES THE CIRCUIT USED BY THE AUTHOR IN RECEIVING THEVICTORY HOUR PROGRAM. HOW TO BUILD THIS PRE -POWER UNIT

WILL BE DESCRIBED NEXT WEEK, ISSUE OF JANUARY 28.

lips Carlin announced the hour was aboutto begin it was easy to tell that trans,mission from Belmore, L. I., where theWEAF antenna is, of voice from the FifthAvenue studio, was up to its usual levelof about the best that there is.

Next Rogers was heard, and his voicewas almost startingly clear, consider-ing early expectations of fidelity lossesdue to land wire carriage. Stone andDorothy suffered from frequency cutoffon both highs and lows, and the malechorus that sang with Dorothy didn'tsound right, due probably to line faults.But Fred Stone alone and Dorothy alone,or in a duet, suffered less from the -han-dicap imposed by the transmission be-cause they were more nearly in the rangeof frequencies not subject to an extra-ordinary amount of distortion.

Kind of Installation UsedJolson did not get an acoustical break

at all. The entire frequency scale wassubject to wave form and amplificationdistortion and severe cutoff at about 200cycles and 2,500 cycles. That line workcan be well done over long distances is'indeed a fact, e. g.. the way Rogers' voicecame in; but that need of hasty routingthrough untried lanes plays havoc withquality was obvious. Quality was utterly

missing from the electrical handling ofthe Jolson broadcast, and his voicesounded tinny.

The Victory Hour was in honor of anew Dodge, the Victory, then on the eveof exhibition to the public, and if the caris as successful as the hour it will earnnever -to -be -forgotten gratitudi.

By the way, my reception was on afour -tube set where the last tube was a210 with 475 volts on the final plate. Thereproducer was a Western Electric 540AW. The combination has excellent fre-quency characteristics.

The technical shortcomings are a neces-sary part of progress and no doubt willshow the way to better reproduction infuture events of this spread-eagle nature.So good was the treatment of Rogers'voice, so superb the acoustical favors be-stowed on Wilmer's voice, that correctionof faults such as in the transmission fromNew Orleans, and to a less extent fromChicago, seems likely.

But one can scarcely avoid remarkingthat the Balkite Hour, a transmissionfrom WJZ and a chain, of the ChicagoOpera Company's stage performanceweekly, although concerning a differentnetwork, is scarcely worth listening to, be-cause the vocal art of the singers and

(Continued on Page 21)

Rogers Is Criticizedfor Joke on Coolidge

Washington.When Will Rogers, during the Victory

Hour, merely made believe he wasturning the microphone over to PresidentCoolidge, he did not announce it was ajoke, and that it was only his imitationof the President that the audience wasto hear. Some letters and telephonecalls, indeed even a few telegrams, pro-testing against the "misrepresentation"were received at the White House. ButPresident Coolidge did not know of themNor had he listened in during the hour.

Some listeners got the idea that it was

truly the President himself who utteredthe humorous speech, instead of Rogers,and they even seemed to get the impres-sion that the President was speaking seri-ously. They deplored the lending of theprestige of a great office to the exploita-tion of a commercial product. Somequite frankly doubted the propriety ofthe imitation-but they did discover it wasonly an imitation.

Mr. Rogers has been President Cool-idge's guest on a few occasions and thePresident has been known to smile atsome of the comedian's remarks.

12 RADIO WORLD January 21, 1928

IN JOINT SONATA PROGRAMS

MATHILDE HARDING, PIANIST, AND ARCADIE BIRKENHOLZ, VIOLIN-IST, ARE HEARD OCCASIONALLY IN JOINT SONATA PROGRAMS OVER

THE RED NETWORK.

Town Makes it a CrimeTo Create Interference

Des Moines, Iowa.The City Council of Fairfield, Iowa, a

college town of 5,000, has passed an ordi-nance prohibiting the use between noonand midnight of all electrical devicescapable of causing interference withbroadcast reception. The use of any"instrument, device or machine whichshall cause electrical interference withradio reception" is prohibited during thesehours. , This includes certain batterychargers, washing machines, vacuumcleaners, motors, dynamos, thermostats,violet ray machines, sign flashers, and allother electrical devices which radiatespark interference in operation.

X -Rays ExceptedThe only exception to the ordinance

is the use of X-ray photographic instru-ments for examination "in emergencycases of physical injuries."

The ordinance is the result of continued

and bitter complaints by radio fans thatthe use of household electrical instru-ments raised, havoc with the reception ofradio entertainment.

The ordinance has not yet been sub-jected to a test by any observed viola-tions, but as the penalty for infractionis a fine of $100 or thirty days' imprison-ment, it is thought that the first arrestwill become a test case.

The Interference is ProhibitedIt will be observed that the ordinance

does not prohibit the use of all electricaldevices which may cause interference butlimits the prohibition to "any instrument,device or machine which shall cause in-terference."

Thus in reality only the interference isprohibited. There are many methodsknown whereby the disturbances causedby electrical instruments can be stopped,including by-pass condensers.

DX SPECIALIST

OWL'S NEST, WHERE PAUL GODLEY TUNES IN DX EACH SUNDA'FROM 12:30 A. M. TILL 2:00 A. IVTHE LARGE RECEIVER IS THE REBROADCASTING MACHINE; THISMALL ONE ON THE TABLE AT TH1RIGHT A SPARE EMERGENCY M?

CHINE.

Godley Starts Seriesfor DX Night Owh

An increased listener interest from thtechnical group of radio owners has bee'reported regarding the DX weekly rebroadcasting periods conducted by PatGodley, radio enginer, at WAAM, Newark, N. J. These periods were tried fothe first time last season and attracte.coast -to -coast attention.

Godley's, purpose was to make distancstations available for local radio -lover:and to show them how to get the maximum distance results out of their ow,sets. This year again, in response to maninquiries Godley announced a series c

broadcasts every Sunday morning ata. m. to run up to February, or untbroadcasting conditions are atmospher:cally less favorable. Godley has fitted ua special set of apparatus at Cedar Grov.N. J., where reception conditions argood.

Power Companies TryNew Wired Radio Stun

Electric light consumers in Ohio, Misouri, Iowa, Illinois, Wisconsin, Calif o,nia and Kentucky, will be able withinshort time to snap a switch on a speci;receiver attached to the light line andten in to any one of three radio prcgrams, which will come from a New Yor,studio, via short waves to the power sttion in each district. The North Amercan Power Company will operate thnew system through its subsidiary, WireRadio, Inc.

The system is based upon the majgpart of the wired wireless inventions c

General George 0. Squier. The speci,receivers will be manufactured by ttGeneral Electric Company, which aidein its development.

WGY. PICKS UP LONDON, SENDS DINNER PROGRAMA dinner program originating at the London Music Hall and broadcast by 5SW, the powerful short wave station of the

British Broadcasting Company at Chelmsford, England, was picked up and rebroadcast recently by WGY, Schenectady; WFBL,Syracuse; WHAM, Rochester, and WMAK, Buffalo, with great success.

The signals in the local sections as well as in many distant points came in with, good volume. Very little fading was noticed.The American stations used broadcast waves.

January 'l. 1028 N A Di 0 \V k) N j) 13

CHILDREN'S HOUR THROUGH WJZ SPREADS DELIGHT

I

(Harold Stein)SONG AND STORY COME FROM THESE YOUNG LIPS AND HANDS FROM WJZ EACH SUNDAYMORNING. THE PERFORMERS HAVE A LOT OF FUN. IT'S GREAT ENJOYMENT FOR THEADULTS, TOO, INCLUDING MILTON J. CROSS, THE ANNOUNCER. HE WORKS DURING THIS HOUR

WITH A HEART AS LIGHT AS ANY CHILD'S.

Heiser Was the Contact Communication Board Naylor Sales Managerfor Putnam Exploration Provided in New Bill of Arcturus Company

Charles T. Heiser made it possible forthe outside world to learn of the progressof the Putnam -Baffin Island Expeditionwhile its members were in wild, hithertounexplored, Fox Basin.

Mr. Heiser, 8DME, member of TheAmerican Radio Relay League, duringthe five months ending in October wascontact at his home in Auburn, New York,for Edward Manley radio operator aboardthe Schooner Morrissey, which conveyedthe Putnam party to the Arctic Circle.Operating under the code call VOQ, Man-ley sent messages and press dispatchesthrough Heiser to the New York Timesand to friends of the expedition.

His equipment for this important work,consisted of the following: Crystal con-trol transmitter working on 38.45 meters.5 watt oscillator, two 71/2 watt frequencydoubling and amplifying stages and oneneutralized 50 watt power amplifier. 350volts on the plate of the oscillator. 67%volts negative grid bias. 600 volts on platesof frequency doublers, 225 volts grid bias,1750 volts on plate of 203A (50 watts) and180 volts negative grid bias. Evereadyheavy duty "B" batteries for grid bias-ing supply were used all through workwith VOQ, during June, July, August,September and part of October.

To. Mr. Heiser's cooperation, Manleyascribed the excellent results he had inmaintaining communications with thiscountry. Mr. Heiser is a noted amateur,and has been interested in both broad-casting and relay work for The Ameri-can Radio Relay League and for theArmy Amateur Stations.

CANARIES ARE ENJOYEDSeveral large orchestras broadcast with

canaries singing with them

Washington.The organization of a Commission of

Communication, consisting of five mem-bers and exercising the powers and dutiesvested in the Radio Commission, as wellas those vested in the Interstate Com-merce Commission, to provide for theregulation of all interstate transmissionof intelligence by wire or radio, was pro-posed in a bill by Senator Couzens ofMichigan to the Senate.

L. P. Naylor is the latest addition tothe corps of radio pioneers, headed byGeorge Lewis, added to the executivestaff of the Arcturus Radio Company, ACtube manufacturers of Newark, NcwJersey.

Mr. Naylor, sales manager of the or-ganization, is a graduate R.E. (ColumbiaUniversity) and made his radio debut inthe rather distant days when crystals wereused as detectors instead of oscillators.

Phantom Stations StirInterference Protest

Washington.The Radio Commission is constantly

given new problems to solve. The latestis that of phantom stations. The com-missioners are not only expected to allo-cate the frequencies to minimize inter-ference between real stations but also toeliminate interference between a realstation and an imaginary station.

At present the Commission is studying areport from F. J. Marco, a Chicago radioengineer, that considerable interference isbeing caused by phantom stations. Mr.Marco reports:

"It may interest you to know that theRadio Engineers Club of Chicago hasspent considerable time in its recent meet-ings, discussing so-called 'phantom sta-tions,' riding through' and 'combinationheterodyning.'

"We are bothered a great deal with allof these troubles in the Chicago territoryand believe that they have not been suf-ficiently considered in apportioning localfrequency and pqwer assignments, al-

though, of course, the commission's workis recognized as being by no means simple.

"It is generally understood that thephantoms are caused by two local fre-quencies combining, due to unavoidablerectification in the first tube of the usualreceiver, giving a third combination fre-quency on which chanel both locals can beheard simultaneously.

"Thus KYW on 570 kilocycles and\VMAQ on 670 kilocycles may combine toform a third frequency of 1,240 kilocycles,which can be heard in some receivers atsome locations.

"Riding through apparently occurswhen one powerful local can be heard ontop of another local's modulation or evenon a distant station.

"Understand, this is not the apparentbroadness of the local station, as the lo-cal may tune quite sharply, completelydisappearing off his frequency, and thenrecurring as the new frequency is tunedin. This is probably due to modulationthat takes place in the first tube."

14 RADIO WORLD January 21, 1928

$8,000, 000 FIRST

YEAR COST OF

NBC PROGRAMSMelvin H. Aylesworth, president of the

National Broadcasting Company, recentlysaid that during its first year more than$8,500,000 was spent on programs sentover N. B. C. networks. He said:

"Our first year of operation has beena year of preparation and of self -educa-tion. It has been a year of learning andof building.

"Through the company's Red, Blue andPacific Coast networks, covering practi-cally the entire United States, approxi-mately $6,000,000 was spent in 1927 in pre-senting radio programs.

$2,000,000 for Talent"In addition to this amount, over $2,-

000,000 was spent for talent alone on spon-sored programs presented by some fiftyAmerican industries who are clients ofthe company. The company itself spentover $500,000 for talent utilized in sus-taining programs presented by itself.

"Wire service tolls alone, for specialcircuits to hook up the stations associatedwith our networks, were in excess of$1,350,000.

"We were the largest user of the Ameri-can Telephone and Telegraph Company'stelephone wire service. Our permanentspecially constructed wire line facilitiesutilize 10,270 miles of wire and on num-erous occasions during the past year,when broadcasting over a nation-widehookup, we have used more than 20,000miles of wire."

50 Stations GroupedFifty stations, Mr. Aylesworth points

out, are now regularly associated with thethree networks. Of these, however, onlyone-WEAF, in New York-is owned byhis company. Two others-WJZ, in NewYork, and WRC, in Washington-ownedby the Radio Corporation of America, aremanaged and operated by the NationalBroadcasting Company.

WGY SHORT WAVE SCHEDULEWGY, Schenectady, which broadcasts

on 790 kc. (379.5 meters) also sends outthe programs on short waves as follows :on Monday, Tuesday, Thursday and Sat-urday nights, on 32.77 meters, over 2XAF;on Wednesday, Friday and Sunday night.on 21.96 meters, over 2XAD.

LOW NOTE SUPPRESSIONWhen the output of your loudspeaker

sounds thin and tiny it is because the lownotes are not present in full force. Onlythe higher notes are reproduced.

Movie Interest AcquiredBy R.C.A. for New Outlet

FBO Pictures Corporation announced entertainment may easily develep as thethat the Radio Corporation of America result of the close affiliation between thehas acquired a substantial interest in that important leaders of motion pictures andcompany, through which methods for the the powerful engineering organization ofreproduction of sound and synchroniza- the radio group. The services of thetion of sound and movies-methods technical staffs of the three greatest elec-controlled by the Radio Corporation and trical companies in the world thus becomeaffiliated companies-will be made avail- available to the motion picture industryable to the motion picture corporation. to help that industry in its constant en -The announcement was made soon after deavor to give the public a new and bet-negotiations had been concluded by Joseph ter entertainment.P. Kennedy, a Boston banker, presidentof the FBO Pictures Corporation, and New Sound ProducerDavid Sarnoff, vice-president and gen- "The first important development of theeral manager of the Radio Corporation. combination will be the presentation of a

The devices and developments of the new method of sound reproduction andRadio Corporation and affiliated compa- synchronization perfected by Generalnies will not be exclusive to the FBO Pic- Electric. The officials of the Radio Corpo-tures Corporation but will be available to ration of America feel that the methodthe entire motion picture industry. and apparatus excel all previous efforts in

the direction of 'talking movies.'Opens Radio to Movies "The Radio Corporation and its asso-A statement accompanying the an- ciated companies have been experiment-

nouncement declared: ing with and d6veloping a method of"This affiliation opens to motion pic- sound reproduction for use in connection

tures for the first time the tremendous with motion pictures for several years,resources and potentialities of radio. It and as it reached perfection decided uponwill give the movies the use of all present a direct affiliation with an establishedpatents and prospective developments of motion picture company as the practicalsound reproduction and synchronization, way of putting it into general use."radio broadcasting, television, etc., of the According to the announcement, twoRadio Corporation of America, the Gen- representatives of the Radio Corporationeral Electric Company and the Westing- and the General Electric Company willhouse Electric and Manufacturing Com- become directors of the FBO Picturespatty. Corporation and its affiliated companies

"A complete revolution of present-day within a short while.

Trick "Studio" ProvidesPlenty of Fun in Home

By H. G. CisinEach season seems to bring some new

accessory or device to add to the enter-tainment or pleasure of the radio setowner. An interesting little device hasmade its appearance this year, whichshows promise of developing into a full-fledged radio fad. This is known as aHomekaster. The Homekaster plugs intoa radio set, like an ordinary vacuum tube.It can be used with any receiver whichutilizes tubes.

There is an extension cord attached toit, which may be strung to another room.At the other end of the cord is a smallmicrophonic device or transmitter. Any -

Political Problems PutOn Air By Noted ExpertsThe "Voters' Service," a school in citi-

zenship conducted by radio by the Leagueof Women Voters, broadcast the first pro-gram recently from Washington and NewYork over the station WEAF and nineassociated stations. The principal speak-ers on the first program were Represen-tative Theodore E. Burton, of Ohio, whospoke in Washington, and Dean VirginiaGildersleeve, of Barnard College, NewYork.

Mr. Burton made a plea for stricter lawenforcement and less sympathy for con-demned criminals. Dean Gildersleeve

spoke on "America First." Merlin H.Aylesworth, president of the NationalBroadcasting Company, and Miss BelleSherwin, president of the League ofWomen Voters, addressed the radio audi-ence. The Paulist Choir sang severalnumbers.

The object of the "Voters' Service," asoutlined by Miss Sherwin, is to give thevoters an impartial review of current poli-tical problems. With this aim in view,addresses will be broadcast by eminentmen and women every Tuesday eveningfrom 7 to 7:30 P. M. until election.

one can talk into the transmitter from theother room and the sounds will be great-ly amplified, coming out of the loud-speaker, just as if the speaker were inthe broadcasting studio. It is possibleto change readily from Homekaster toordinary broadcasting.

Hundreds of interesting, entertainingand mystifying stunts are possible withthe Homekaster. Take your friend theDX hound, who is always bragging aboutvast distances which his radio can receive.Set him before your radio and show himhow easy it is to get 2LO, London. Thisought to keep him quiet f,pr a while.

A Homekast party is enjoyable. Thehostess invites talented friends to "Home-kast," locating the "studio" in a room up-stairs. The other guests are informedthat the broadcasting is from one of thelocal stations. Immediately after thecompletion of the performance, the enter-tainers surprise everyone by walking inas their praises are being sung. Ofcourse, it is just possible that a performermay arrive from the "studio" in time tohear comments not so complimentary. Atany rate, this hoax furnishes plenty ofamusement for the guests, say personswho tried out the Homekaster.

NO CHANGE BEFORE FEB. 1Washington.

The broadcasting stations' waves, power,hours on the air, etc., as now constituted,will not be changed until February 1, theFederal Radio Commission decided.

January 21, 1928 RADIO WORLD 15

DR. GOLDSMITH

ELECTED HEAD

OF INSTITUTEDr. Alfred N. Goldsmith, Chief Broad-

cast Engineer of the Radio Corporationof America, was installed as President ofthe Institute of Radio Engineers at itsfirst executive session of the third annualconvention in the auditorium of the Engi-neering Societies Building, New YcirkCity. L. E. Whittemore, of the Depart-ment of Development and Research of theAmerican Telephone and Telegraph Com-pany, was elected Vice -President.

New managers elected by the institutewere: Dr. J. H. Dellinger, Chief of theRadio Section of the Bureau of Stand-ards, Washington, and R. H. Manson,Chief Engineer of the Stromberg-CarlsonTelephone Manufacturing Company ofRochester, N. Y.

Hogan Honored

J. V. L. Hogan, consulting radio engi-neer of New York, was appointed by thedirectors to fill the place of the late Col.John F. Dillon, Federal Radio Commis-sioner. Other managers appointed by thedirectors were Louis A. Hazeltine, AlfredH. Grebe, Dr. W. G. Cady, and ArthurBatcheller.

Dr. A. Hoyt Taylor, of the Radio Di-vision of the United States Naval Re-search Laboratory, Bellevue, Anacostia.D. C., won the Morris Liebmann MemorialPrize for 1927 for his investigation ofradio transmission on short wave lengths.

Gets $500 Cash

The award carries a medal and $500in cash.

The presentation of the award wasmade by Dr. Ralph Bown, of the Ameri-can Telephone and Telegraph Company,retiring President of the institute.

Dr. Taylor was graduated fromNorthwestern University in 1899 withthe degree of Batchelor of Science.Then he taught physics in MichiganState College, Lansing, and in 1909 he ob-tained his doctor's degree from the Uni-versity of Gottingen, Germany.

He became transatlantic communicationofficer of the Navy in 1917 and was as-signed to the radio station at Belmar, N. J.

HARMONIC INTERFERENCEThere is still interference between

broadcasting stations, although the Fed-eral Radio Commission has accomplisheda great deal to reduce it. There re-mains one type of interference which ap-parently could be eliminated withoutmuch trouble, and that is the interferencebetween two stations one of which oper-ates on the second harmonic of theother.

SPEECH NEEDS HIGHFREQUENCIES

When the output of your loudspeakersounds well on music but is not easilyunderstood on the spoken voice it is verylikely due to the absence of the higheraudible notes. Frequencies as high as5,000 should be strongly reproduced ifspeech is to be clearly understood. Notmany receivers are able to reproducemuch over 5,000, particularly very se-lective receivers.

"SHAKE!" SAID BOWN; GOLDSMITH DID

(Herbert Photos)

DR. RALPH BOWN, RETIRING PRESIDENT OF THE INSTITUTE OF RADIOENGINEERS, WELCOMING HIS SUCCESSOR TO THAT HIGH OFFICE-DR.

ALFRED N. GOLDSMITH (AT RIGHT).

de Gogorza Will TeachKent Audition Winners

Banking their $10,000 cash prizes andpacking away their laurel wreaths andcongratulatory telegrams, Miss Agnes Da-vis and Wilbur Evans, the Denver so-prano and Philadelphia baritone who wonfirst place in the Atwater Kent Founda-tion's National Radio Audition, havestarted to collect the second part of theAudition reward-two years' musical con-servatory scholarship, which is intendedto make them even greater singers.

Both of these young soloists, who out-classed 50,000 other vocalists in the audi-tion, have been accepted as personal pu-pils of Emilio de Gogorza, the world-re-nowned baritone, formerly of the Metro-politan Opera in New York and now acelebrated concert artist.

To musicians, that announcement spellsa triumph for Agnes Davis and Evans-for de Gogorza takes less than half adozen pupils, and those who, after sever-est tests, convince him that they can bedeveloped into singers of the finest op-eratic quality. No amount of money or"pull" could obtain the services of deGogorza for a pupil he felt was unworthyof his time.

For two years de Gogorza will per-sonally tutor Miss Davis and WilburEvans, at the Curtis Institute of Music

in Philadelphia.Evans has Been studying under de

Gogorza at the Curtis Institute for threeyears, pluckily acquiring funds for thesevalued lessons by various tasks such asteaching swimming to children, chauffeur-ing and clerking. Now, as the AtwaterKent Foundation's protege, he can con-centrate his efforts on making his winningvoice even finer. Next Summer, expend-ing part of the Foundation's cash award,he will accompany de Gogorza to Paris,for advanced study there.

Miss Davis also is planning to studyabroad next Summer.

Winners of second and third places inthe National Radio Audition, who alsoreceived scholarships of one year each,are preparing to start this study. Ted A.Roy, "the singing blacksmith" of Corval-lis, Ore., who placed second, has ar-ranged to complete his studies at OregonState College, graduating in 1929, beforetaking up the musical scholarship.

Miss Emilia Da Prato of South SanFrancisco, Cal., who placed second inthe ladies' division, and Marie Bronar-zyk of Chicago and Ben P. De Loache,Jr., Asheville, N. C., third place winners,are expected to decide soon where theywill study.

16 RADIO WORLD January 21, 1928

BILLS PROVIDE Commission's PoliciesFOR EXTENDING Criticized by WhiteLIFE OF BOARD

Washington.Extension of the administrative life of

the Federal Radio Commission for oneyear is proposed in a bill which SenatorWatson (Rep.), of Indiana, introduced.

A similar bill was introduced in theHouse. It was indicated that early actionby Congress would be sought, as theCommission's original jurisdiction overradio expires in March, 1928.

Under the Radio Law of 1927, thepresent Commission adverts to quasi-judi-cial functions, handling appeals from theRadio Division of the Department ofCommerce, which assumes the control andregulation of radio in the United States.

The full text of Watson's bill follows:"Be it enacted by the Senate and House

of Representatives in Congress assem-bled, That all the powers and authorityvested in the Federal Radio Commissionby the Radio Act of 1927, approved Feb-ruary. 23, 1927, shall continue to be vest-ed in and exercised by the Commissionuntil March 16, 1929; and wherever anyreference is made in such act to theperiod of one year aftet the first meetingof the Commission, such reference shallbe held to mean the period of two yearsafter the first meeting of the Commis-sion.

"2. The period during which the mem-bers of the Commission shall receive com-pensation at the fate of $10,000 per an-num is hereby extended until March 16,1929."

* * *

Hoover Approves ExtensionWashington.

Secretary of Commerce, Hoover, ex-pressed approval of the proposals in Con-gress to prolong the Federal Radio Com-mission's authority over radio untilMarch 10, 1929.

BOARD PLANS ENDINGCONCURRENT USE OF WAVE

BY TWO STATIONSWashington.

Itself not satisfied that even greatgeographical separation does not preventinterference between two stations operat-ing at the same time on the same fre-quency, the Federal Radio Commission isplanning to afford 5 kilocycle separationto replace identical assignments to dis-tant stations.

AN INTERFERENCE FACTORYThe fellow who lives on the other side

of the wall, who has strung his antennaparallel to yours, and who operates asingle circuit regenerative receiver, cancreate all the interference tabulated inthe office of the Radio Commission anda good many brands of his own.

Finds Licenses Too Freely Granted, Number of Stations StillSame and Court Decision on Powers Averted-Chain

Advertising and Monopoly Up For Discussion

Washington.The Federal Radio Commission's work

fell short of Congressional expectations,said Representative Wallace H. White,Jr. (Rep., Lewiston, Maine), chairman ofthe Committee on Merchant Marine andFisheries, but he introduced a bill in theHouse to continue the Comrnission foranother year so that the Commissionwould have a good opportunity to makeup for lost ground. He proposed amend-ments to the law other than mere con-tinuation.

He recognized the handicaps the Com-mission had to suffer and directed his crit-icism toward policies of the Commission.He said in part:

"It has seemed to me that the Commis-sion has completely failed to measure upto expectations in some particulars.

"It did not require applicants to makean affirmative showing that the opera-tion of their stations would serve thepublic interest but it automatically is-sued licenses under the new law to allapplying therefor.

"This may not be strictly accurate butit is sufficiently so for the present state-ment.

Sentence 218 Words Long"The result is that today there are sub-

stantially the same number of broadcast-ing stations as when the Commission be-gan its activities; there is the same ut-terly inexcusable concentration of stationsin certain congested areas; there is thesame absence of stations in many partsof the United States; and it seems to methat the fact itself of the issuance ofa license under the new law makes itmuch more difficult now either to reducethe number of stations or to force arelocation of them in less congestedareas throughout the United States; andit seems to me that the fact itself ofthe issuance of a license under the newlaw makes it much more difficult noweither to reduce the number of stations

-or to force a relocation of them in lesscongested areas throughout the UnitedStates (for the station which the Com-mission might now seek to eliminate isin operation with the express approvalof the Commission, and is fortified inits claim for continued existence andoperation, by the finding, express or im-plied, of the Commission that it is serv-ing a public interest or convenience,otherwise it would not be licensed at all),and all of which threatens increased con-fusion in transmission, if the areas nowwithout stations are to have their localneeds met by additional stations withinsuch areas."

Home Models DuplicateHorse Race at the Track

London.Another use for radio was discovered

when Dr. J. H. Roberts, electrician, de-vised a home race course with woodenmodel horses, which run the course as .dothe thoroughbreds at the track. Radioimpulses from the operator at the field

determine the speed and position of themodels, based on the actual track per-formance.

"Telemotion" is Dr. Roberts' name forit, and he sees possibilities for it in allbranches of sport.

His invention aroused much interest

Following this sentence, containing 218words, Representative White said theCommission should not have issued licen-ses promiscuously and should not haveaverted a legal determination of the rightto order stations to discontinue.

Opens Way to Discuss ClaimsOn the subject of claim broadcasting

and monopoly he said:"Another amendment which I am of-

fering enlarges the authority of the Com-mission with respect to chain broad-casting. It gives the.. Commission thepower to fix the time during which chainbroadcasting may be carried on, to des-ignate the stations which may be in ageneral or in a particular hookup, tolimit the number of stations which maytake part in one of these chain broad-casting programs and it authorizes theCommission to impose special conditionswith respect to the wave length and powerto be used.

"It also gives the Commission authorityto prohibit commercial advertising througha chain of stations.

"I ant introducing this provision to pro-voke discussion of this general subjectin the hope that from such discussionthere may come a clarification of views,rather than because I am affirmativelyfor the provision as I have drafted it.I am in a doubtful frame of mind as towhat can be done or as to what shouldbe done, if anything. I hope this proposedamendment will be productive of discus-sion from which Congress can reachsome settled and sound opinion on thisphase of radio communication.

Wants Monopoly Question Studied"Another amendment is aimed directlyat the alleged monoply in radio patents.I am not yet certain that in the Commit-tee I shall approve this provision. I haveincluded it in this bill for much the samereason that I have incorporated the pro-vision with respect to chain broadcasting."This question of radio patents is con-tinually discussed. There is a widespread

feeling of dissatisfaction with the existingsituation. I hope that the question can beopened up before our Committee."

Work of CommissionSplendid, Says Sarnoff

By DAVID SARNOFFVice -President and General Manager

Radio Corporation of AmericaThe work of the Federal Radio Com-mission has been splendid. The Commis-sion has brought order out of impendingchaos in the air. It is effectively policing

the channels of space and is giving theradio listening public of the country thedeserved opportunity for unimpeded re-ception of the musical, educational andinformational features which radio bringsto the home.

SALTZMAN TO RETIREMajor General Charles McK. Saltzman,chief of the Army Signal Corps, and di-rector of Army radio activities, is soonto retire, after 30 years of service.

January 21, 1928 RADIO WORLD 17

WAVE MAZE Kickers Have Their SaySTILL HERE, on Commission's Work

SAY MANYReaders have written to RADIO WORLD

on the subject of wavelength assignments,hours on the air, power, etc., and whilenearly all admit improvement, many com-plain there is still far too much inter-ference. Heterodyne whistles, wave wob-bling and assignment of two stations tobroadcast on the same wave at the sametime stirred protests.

Panels for All CircuitsUpon their removal to their new

quarters at 165 Greenwich Street, Cort-landt Panel Engraving Company have in-augurated the policy of carrying instock drilled and engraved panels for allpopular circuits. This means a greatsaving in time to fans, dealers, manu-facturers and mail order houses in needof such panels at once. Among the pan-els are Magnaformer 9-8, Silver -Mar-shall circuits, World's Record Super 8,9, 10, Camfield 7, 9 and 10, Tyrman 10and 7, Nine -In -Line, Karas Equamaticmodels, Victoreen, Melo-Heald Eleven andFourteen, Browning -Drake, Lynch Five,Hammarlund Hi -Q, the Everyman 4 andthe old popular favorite, Diamond of theAir. Under the direction of J. Sprungthis concern is far in the lead. The con-cern is one of the oldest in the business.-J. H. C.

A TICKLER EXPERIMENTAny regenerative receiver can be tuned

so that the low notes predominately and thus make speech as reproducedby the receiver poorly understood. Itcan he tuned also to bring out the highwith equal force to the low. It is onlynecessary to reverse the tickler.

WASHINGTON.Senator Watson, chairman of the Com-

mittee on Interstate Commerce, presidedover a hearing of his Committee on theconfirmation of President Coolidge's ap-pointments of three members of the Fed-eral Radio Commission-O. H. Caldwell,of New York; Sam Pickard, of Kansas,and H. A. Lafount, of Utah.

Independent broadcasters entered com-plaint against alleged arbitrary rulingsand assignments on the part of the RadioCommission which, they claimed, werefavorable toward chain stations than to-ward those not affiliated with the nationalnetworks.

Commissioners Pickard and Caldwelltestified in their own behalf as to theirqualifications for office. CommissionerLafount has not yet returned from theinspection tour of his far western radiozone.

The Senate Committee's inquiry, how-ever, was directed largely to the policiespursued by the Commission in its assign-ments of wavelengths, power and hoursof broadcasting to the 685 stations in theUnited States. The patent situation inthe radio industry was also mentioned, aswas the short wave situation.

Commissioner Pickard, a Democraticappointee, testified that he claimed thatparty affiliation and that his residencewas Kansas, in response to the questionraised as to his qualifications to repre-sent the fourth radio zone of MiddleWestern States. Senator Dill (Dem.), ofthe State of Washington, quoted the radiolaw and the statutes to elucidate Com-missioner Pickard's status under the "ac-tual residence" requirement of the radiolaw, when Mr. Pickard stated that hehad come to Washington, D. C., fromManhattan, Kans., to organize the RadioDivision of the Department of Agricul-

Ormiston's MagnaformerAhead With CeCo Tubes

Such great distance reception was ob-tained by K. G. Ormiston on his Magna -former 9-8 that many readers of the Magna -former article by J. E. Anderson in our De-cember 10 issue asked that the exact tubeshe used be cited. So a letter was written toMr. Ormiston in care of "Radio Doings,"Los Angeles, of which he is TechnicalEditor. His reply follows:

Editor RADIO WORLD:Early in September, before the Sum-

mer static had really abated, I was ableto bring in two Japanese stations (JOAKand JOCK) and two Australians (2BLand 5CL) at Manhattan Beach, California,using the standard 1VIgnaformer 9-8,operating on eight tubes. Tubes used wereCeCo throughout ; "H" type as first and

second detectors, "K" type in the inter-mediate frequency stages, an "A" in thefirst audio and "J-71" in the output stage.I used only the loop for pick-up and thesestations were brought in on the loud-speaker, a large Newcombe -Hawley air -column. This performance has been re-peated very often since that date, and atmany locations.

At Lake Arrowhead one night welogged 60 stations outside California,-including WGY, WABC, KDKA, eight inChicago, eight in Canada, etc.

We presented the Magnaformer 9-8with a three terminal loop and small mid-get condenser controlling regeneration ofthe first detector.

K. G. ORMISTON,Technical Editor "Radio Doings."

The Magnaformer 9-8 ByJ. E. Anderson

The pinnacle of achievement in the pre-sentation of a circuit marked the seven -full -Page article by J. R. Anderson, Tech-nical Editor, in the Dec. 10 issue of RadioWorld.

Read this fascinating, expert, complete exposition, illustrated in colors.) This article evoked 700 laudatory letters. Send 15c for Dec. 10 issue.

RADIO WORLD, 145 West 45th St., N. Y. City

ture and later had become secretary ofthe Federal Radio Commission.

Although Congress had intended theradio appointees be actual residents, Mr.Dill said he was satisfied that under thelaw Mr. Pickard fulfilled legal require-ments.

Intends No "Freezing"Commissioner Pickard, responding to

questioning by Senator Fess (Rep.), ofOhio, asserted that since he took officelast November 1, succeeding former Com-missioner H. A. Bellows, resigned, hehas been viewing the broadcast problemsolely from the viewpoint of the listener,particularly the rural and remote listener.

He said that the Radio Commission hasno intention of "freezing" the presentbroadcasting situation by assigning long-term licenses either to the chain or toany other stations before its administra-tive life lapses about March 15, 1928, un-der the radio act.

He said he had not given considerationto the short wave problem, which was inthe hands of the late chairman of theCommission, Admiral W. H. G. Bullard,and is now being handled by Commis-sioner Caldwell.

Senator Dill produced a letter whichcharged that 47 short waves had beengranted the Radio Corporation of Ameri-ca and 39 to land communication compa-nies, but he also quoted the secretary ofthe Radio Commission, Carl H. Butman,to show that of 56 short wave licensesthat have been granted 15 were assignedthe R. C. A. and four to the AmericanTelephone and Telegraph Co.

5,000 Short Waves AvailableMr. Pickard said that recent estimates

have shown that at least 5,000 wavesare available in the short wave band,where long distance code communi-cation, television and facsimilie transmis-sion, can best be carried out, but that theCommission has not issued any licensessince November 1, as far as he was aware.

Commissioner Pickard's appointmentand that of Commissioner Caldwell wereopposed by D. W. May, operator ofWTRL, of Midland Park, N. J., operatedby the Technical Radio Laboratory, whoasserted that both of these men haveruled or have shown arbitrary attitudein favor of a "monopoly of the air," whichhe said was represented by the chain ofthe National Broadcasting Company. Heasserted that the small broadcasters havebeen unable to carry their troubles to thecourts because of the expense entailed ininstituting suits in the District of Colum-bia courts.

Opposition by May and BakerJudge E. 0. Sykes, acting chairman

of the Federal Radio Commission, uponrequest of the Committee, asserted thatthough several suits have been fledagainst the Commission those alleging un-constitutionality of the radio law or ofthe Commission's rulings under the lawhave been dropped, while several are pend-ing which relate only to appeals fromfindings of fact.

Mr. May offered as a possible solutionof the congested broadcasting situationan assignment plan by Paul Ware, con-sulting radio engineer, director of thelaboratory of Splitdorf Radio Corpora-tion, Newark, N. J., and he urged thesynchronization of all chain programs onthe same or on only a few wavelengths.

Further testimony in opposition to thepolicies was presented by Norman T.Baker.

18---------

RADIO WORLD January 21, 1928A THOUGHT FOR THE WEEK

W'lERE'S iliat man we've been expect-tig to hear from` We mean the chap

who some day will tell a palpitant worldthat if all the wire used in wireless in oneyear were placed end to end it would reachfrom the R. C. A. Offices in New York Cityaround the world four thousand, six hun-dred and seventy-seven times and that therestill would be enough over to cover thedistance between the finite and the infinite.

SIXTH YEAR

The First and Only National Radio Weekly

Radio World's Slogan: "A radio set for every horne."

TELEPHONES: BRYANT 0558, 0559PUBLISHED RYSIRY WEDNESDAY

(Dated Saturday of same week)FROM PUBLICATION OFFICE

HENNESSY RADIO PUBLICATIONS CORPORATION145 WEST 45TH STREET. NEW YORK, N. Y.

(Just east of Broadway)ROL.AND BURKE HENNESSY, President

M. B. HENNESSY, Vice -PresidentHERMAN BERNARD. SecretaryChicago: 55 West Jackson Blvd.

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EDITOR, Roland Burke HennessyMANAGING EDITOR, Herman BernardTECHNICAL EDITOR, J. E. Anderson

ART EDITOR, Anthony Soder°CONTRIBUTING EDITORS:

James H. Carroll, John Murray Barron andCapt. Peter V. O'Rourke

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Receipt by new subscribers of the first copy of RADIOWORLD mailed to them after sending In their order Isautomatic acknowledgment of their subscription order.Changes of address should he received at this office twoweeks before date of publication. Always glue old address;also state whether subscription is new or a renewal.

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Entered as second-class matter March 23, 1922. etthe Post Office at New York, N. Y.. under the Act ofMarch 3, 1079.

MARCONI FACED RIDICULEWhen Marconi went to England with

his wireless invention many personsscoffed at him and he was the subject ofmany newspaper jokes. Bankers ad-vised their clients to avoid the stock ofthe Marconi company, even after wirelesshad been demonstrated to be practical.

"ELECTRIC" AND "ELECTRIFIED"All receivers are electric sets. But pop-

ularly a set is only electric when all thetubes in the receiver are heated with rawalternating current and no batteries areused for any purpose. If the set is so ar-ranged that standard DC tubes are usedwith trickle charger it is called electri-fied.

What Shall BeDone About Stations?

Must Get Rid of Excess, Says Head of Iowa League-ComplainsDirect Selling Talks "Make American Radio the LaughingStock of Other Countries"-Comment by Readers.

Francis St. Austell, president of theIowa Radio Listeners' League, DesMoines, broadcasting from WEAF, said:

"The only claim that the broadcasterhas to the use of the air must be basedon service to the listening public. Butup to the present the public has beenhaving things done to it instead of doingthings for its own benefit.

"Listeners, broadcasters and authori-ties may just as well realize now thatthere are too many stations on the airand that some must go. The listeningpublic had better get busy and tell theauthorities which stations it is desirableto retain.

"It is of public interest that the peoplehear the best that radio has to offer. Itis a real necessity that this should beprovided if the radio industry is to live.But it is not of public interest, necessityor convenience that mediocre perform-ances coming from stations so anxiousto serve their own interests that theybecome a nuisance to the general public,remain on the air.

"Laughing Stock""Stations that devote their efforts large-

ly to direct selling-pouring out voicif-erous calls for orders for prunes, pickles,toothpaste, peaches or potatoes-makeAmerican radio the laughing stock ofother countries.

"What the listener wants is radio andgood radio-all the year round, regardlessof weather conditions. Such a service canonly be given by a chain of powerfulstations extending completely across thecountry.

"The listener wants radio deliveredto his loudspeaker in a dignified, pleasingway, with good announcing and correctspeech. He wants the best and he is en-titled to it. He gets that from those sta-tions that not only employ good local

EDITOR RADIO WORLD:I do not blame the Federal Radio Com-

mission, but the promised clearing of thebroadcasting channels has not helped agreat deal. Much squealing and hetero-dyning can be heard every evening, par-ticularly when an attempt is made toreach out 1,000 or 2,000 miles for a pro-gram. It is evidently short wave stationswhich cause interference with the sta-tions operating on the longer waves. Andthis coupled with the fact that nobody isinterested in the small stations for theirown service to the public, seems to af-ford a simple solution to the whole intol-erable situation, and it is a radical re-duction in the number of stations per-mitted to operate.

If there is any objection from theowners of stations threatened with ex-tinction, let the public aid the commis-sion in deciding the issue. Public serv-ice, convenience and necessity accordingto the law are to determine which are toremain and which must go. Certainly thestations to which nobody listens willinglyare no public convenience, and the fanswould not hesitate to state that in a voteon the subject if given a chance to vote.And nobody can claim that it is a neces-sity to have three or four bundred sta-tions all over the country when 99% ofthe entire body of listeners confine theirattention to about a score of the best sta-tions.

JOSEPH P. SULLIVAN.

talent but which also provide their au-diences with the wonderful programsoriginating in New York and sent outover the chains of the National Broad-casting Company.

Question of Investment"Broadcasters clamor about their in-

vestment. Their investment amounts tovery little when compared to that of thelistening public. And often it is thebroadcaster who delivers the least in realservice who shouts loudest about his rightsto be on the air.

"Listeners are coming to realize thatthe greatest programs originate in thelarge centers, particularly New York, be-cause the talent is there and can be pro-duced ill one studio. The sponsors ofthese programs could not afford this tal-ent even if it was available, if he had tosend it by train to each station.

"It is quite certain that the listenersthroughout the country are going to de-mand a clear right-of-way for nationalprograms. By national programs I meanprograms sent from our real nationalcenters, such as New York or Chicago,and delivered to our speakers through thelocal stations affiliated with one or moreof the great hookups.

Difference In Tastes"Of course tastes in radio differ. The

city man apparently wants entertainmentfirst and education and information insmall doses later. The farmer wants in-formation, religious services, markets,weather and crop reports and agriculturalinformation first and then is ready to beentertained.

"But both farmer and city Irian agreeon one point. Both want to hear clearradio, without the interference and hetero-dyning that so often takes possession ofthe air today.

* *

EDITOR RADIO WORLD:I have been a rabid radio fan for sev-

eral years but the present state of broad-casting makes it almost impossible forme to retain full interest in the subject.Not only is it impossible to get any ofthe distant stations clear without hetero-dyne interference but often the programsfrom local stations are spoiled by whistlesand growls which do not originate in os-cillating receivers. No, they are due tothe many superfluous stations which arecontinually on the air with their selfishinterests in the guise of entertainment.

If these stations offered somethingworthy of a radio listener's attention nowand then it would not be so bad, but theynever do. They put on singers who neverwill be able to sing; they put on playerswho do not know the difference betweena cello and a saxophone; they put on edu-cational features by persons who them-selves do not know what they are talkingabout. Some of them put on phono-graph and player piano music and con-vert good reproduction into burlesquetransmission.

The only solution to this intolerablesituation is to force half of the presentstations off the air. They do not servethe public as the law requires them to doand therefore they have no claim whatso-ever to a place in the ether.

Speed up the day when all this inter-ference is eliminated.

FRANCIS R. ABERCROMBIE.

January 21, 1928 RADIO WORLD 19

Tube Patent DecisionBoon to Independents

Grant to Langmuir on High Vacuum Set Aside by Lowest FederalCourt as G. E. Loses Suit Against DeForest-Two Other

Patents Voided, One Sustained

Wilmington, Del.Federal Judge Hugh N. Morris has

handed down an opinion dismissing thesuit of the General Electric Companyagainst the De Forest Radio Company inwhich it was sought to restrain the DeForest Company from making and usingradio apparatus, claiming infringement offour basic radio patents. The GeneralElectric Company will take an appeal, itis expected.

The General Electric Company chargedthat the De Forest Company was infring-ing on patents, granted to Irving Lang-muir and assigned lay him to the GeneralElectric Company, for electrical dischargeapparatus and the process of manufactureand the use of tubes employed in radiobroadcasting and reception. The tubes areknown in the electrical field as "highvacuum tubes."

The court held that the first and mainpatent of the four is invalid in view ofprior art and because it lacked patentablenovelty as well as for other reasons. Thecourt upheld only one patent, which cov-ers the use of potassium in radio tubes.

* * *

Arthur D. Lord, receiver for the DeForestRadio Company, reviewed the decision givenby Judge Morris as follows:

Judge Morris decided the suit of theGeneral Electric Company against theDeForest Radio Company brought for in-fringement of the Langmuir high vacuumpatents.

The principal patent of this group,which it has been asserted by the RadioCorporation, the General Electric Com-pany, and their associated companies, tocompletely blanket the vacuum tube art,specifically including radio tubes, had allits claims declared invalid for a numberof reasons. This patent-No. 1,558,436-was granted on October 20th, 1925. Irv-ing Langmuir, research engineer of theGeneral Electric Company, was the pat-entee.

If the patent had been sustained itwould have run for seventeen years fromthe date of its issuance and hence wouldnot have expired until October 20th, 1942.The patent was asserted to cover anyvacuum tube which had a high enoughvacuum in it to permit a plate voltageof 40 volts to be employed without appre-ciable ionization effects. This in effectcovered every vacuum tube used today.

Lists Three ReasonsThe court held the patent to be invalid

for each of the following reasons :(1) Because Langmuir was not the first

inventor of the subject matter, in otherwords other and prior investigators haddone the same thing. As stated by theopinion:

But disclosures of the prior art re-veal that Langmuir, great and renownedphysicist that he is justly stated to be, inthis instance, travelling all unknown tohim, over a field already well explored."

(2) Because Dr. Lee DeForest had hadprevious knowledge of the invention andhad actually used the alleged invention inCalifornia in 1912, a year before Lang-muir had ever seen a vacuum tube of thethree electrode type.

(3) Because Dr. Harold DeForest Ar-nold of the Western Electric Company

had conceived and utilized the vacuumtubes operating on the pure electron flowtheory, as distinguished from gas ioniza--tion theory, before Langmuir, had anyconception of the alleged invention ofthe patent. Arnold and Langmuir foughtthrough an intereference proceeding inthe Patent Office, each claiming to havebeen the inventor of the subject matterof the patent. The Examiner of Inter-ferences and the Board of Examiners -in -Chief in the Patent Office both heldin favor of Langmuir but the Commis-sioner of Patents held in favor of Ar-nold.

One Way and AnotherThe Court of Appeals of the District

of Columbia, to which court appeal wastaken by Langmuir, held in favor ofLangmuir. Judge Morris in this casedisagreed with the Court of Appeals ofthe District of Columbia and adoptedthe opinion of the Commissioner of Pat-ents, holding that if any invention hadbeen made Arnold made it.

The determination of this point, how-ever, is of no practical effect, because thecourt concluded that no invention hadbeen made by anyone and went into thissubject to show that Langmuir, the pat-entee. had wrongfully obtained a patent,as even if it were conceded that an in-vention had been made, Langmuir wasnot the first inventor.

The Logical ThingWith respect to the companion Lang-

muir vacuum patent involved in the litiga-tion, the court in its opinion concludedthat the second patent-No. 1,244,216 --granted October 23rd, 1917, directed tothe use of a thoriated tungsten filamentin a high vacuum for radio tubes, wasinvalid as being the mere adoption anduse of a filament standard in incandes-

cent lamp practice in vacuum tube prac-tice.

The court pointed out that with theadvent of carbon filament in incandescentlamps carbon filaments were adopted forcarbon tubes and that, therefore, asrapidly as a filament was developed forincandescent lamp work it was adoptedfor vacuum tube work.

Hence when thoriated tungsten filamentwas adopted for incandescent lamp workit was the most natural and logical thingto do to use it with filament for vacuumtubes. Consequenly, anyone who did itmade no invention in doing it.

The third of the associated patents-No. 1,529,597, granted March 10, 1925, andknown as the magnesium flash patent, waslikewise declared to be invalid. This pat-ent is directed to employing magnesiumas a vaporiable agent for "getting" and"keeping" a high vacuum chemically. Thecourt found that this patent disclosed noinvention in view of the knowledge manyyears before it of the employment offlash material for the same purpose, speci-fically including magnesium, the subjectof the patent, in vacuum tubes, specifi-cally including radio tubes.

Where Langmuir Led WayThe fourth patent, of the group-No.

1.244,217-granted October 23rd, 1917, washeld to be valid by the court and claims1 and 4 to be infringed by the defendant.This patent is known as the potassiumgetter and keeper patent. This materialis used for assisting the getting of avacuum and maintaining the vacuumafter it has been obtained.

The court concluded that while manyin the prior art had used a similar ma-terial to get a vacuum Langmuir, in hisopinion, was the first to use that ma-terial for not only getting the vacuum butfor keeping it after it had been gotten.

If the first of these patents had beensustained it would have been impossiblefor anyone to manufacture independentlyany radio tube used today until after1942.

Dr. De Forest's Comment"Had the Langmuir patents been sus-

tained," said Dr. De Forest, "there is noquestion that within the next year nearlyall of the independent manufacturers ofradio tubes would have to go out of busi-ness. We expected the decision."

An appeal is being prepared by theplaintiff.

Daven A C ResistorsProvide Exact Center

To minimize the hum in electrified re-ceiving sets, many manufacturers in-corporate center top AC filament resist-ors. The value of these resistors rangesfrom 2 to 60 ohms, depending upon thenumber of tubes and the current supply.

Efficiency of these center tap resistorsdepends upon how closely the tap ap-proaches a true electrical center for gridreturn connections. To this end, theDaven Radio Corporation has developeda wire wound center tap AC resistor thatis wound from each end inward, with thetwo matched windings connected at themid -point. This is the best known prac-tice for arriving at a true node point.

Resistors of this type are now availableto set constructors for application in anycircuit calling for 10, 25, and 60 ohmsizes.

FRACTIONAL HENRYSThe terms millihenry and microhenry

confuse many. A millihenry is equal to.001 (one one -thousandth) of a henry,while a microhenry is equal to (one one -millionth) of a henry.

More Space for Splitdorf;Four Executives HonoredTo meet the needs for the enlarged

radio programme for 1928 the SpiltdorfRadio Corporation, of Newark, N. J. hasacquired an additional 100,000 feet offloor space by taking over the buildingnearby, formerly occupied by the Boy-den Shoe Co. Every facility for thebuilding of radio receivers and loud-speakers is provided.

At the same time announcement ismade that the Splitdorf Radio activitieshave been placed under the direction ofHal P. Shearer, general manager; NoelS. Dunbar, advertising manager; PaulWare, director of laboratory, with SamSchaeffer as assistant advertising mana-ger.

SAMSON'S BOOK FOR STATIONSIn the discussion of the 24 page book-

let on transformers issued by SamsonElectric Co., Canton, Mass., it was statedthat the equipment applied to telephonetransmission. This of course includesbroadcasting stations, for whose benefit inparticular the booklet is issued.

RADIO WORLD January 21, 1928

Action of a CondenserExplained for Novices

By Brewster LeeTHE electrical condenser often is a

stumbling block to students of ele-mentary electricity. First they are toldthat a condenser can be charged withelectricity and that it retains this chargefor a while. Then they are told that acondenser is an open circuit throughwhich no electricity can flow. These twostatements are not contradictory and offerno trouble. The student simply visualizesa closed vessel into which some kindof fluid is poured. The vessel can be filledand no more.

But when the student takes up the sub-ject of alternating current he is toldthat current can flow through an elec-trical condenser, indeed that under someconditions the condensers is a short cir-cuit which offers practically no imped-ance to the flow of the current.' How canthe condenser be an open and a closedcircuit at the same time? That questionin some form or other always enters thestudent's mind.

As a matter of fact the condenser, ifit is a good condenser, is a closed circuitto alternating current as well as to directcurrent. But that does not prevent alter-nating current from flowing in a circuitin which a condenser forms a part. Thealternating current does not flow throughthe condenser. It bows in and out ofthe condenser.

Instructive hydraulic analogies can beconstructed easily to help to understand-ing the action of an electrical condenser.With respect to a condenser, electricityacts much the same as does an elasticfluid like acts. It resists compression.

Let us then liken the condenser to anairtight tank into which air may be forcedwith a suitable pump. The pump thentakes the place of a charging battery.By means of it air can be pumped into thetank until the pressure exerted by the airin the tank is equal to the pressure onthe piston. Likewise electricity can beforced into a condenser with a batteryuntil the back pressure of the electricityin the condenser equals the pressure ofthe battery.

Equalized Pressures

When the pressures have been equalizedthe condenser is said to be charged tothe voltage, or pressure, of the battery,and the tank is said to be pumped up tothe pressure of the piston. The electri-cal pressure is measured in volts, thepressure of the air in atmospheres.

If there is a leak in the condenser thecharge will leak off at a rate dependingon the magnitude of the leak. The dis-charge may take minutes or days. Thesame holds of the air tank. If there isa leak, the compressed air escapes ata rate depending on the size of the open-ing.

But suppose there is no leak in either.The condenser can be charged to a veryhigh voltage or electrical pressure. Butit cannot withstand unlimited pressure.As the voltage is increased a time willcome when there will be an explosion, arupture of the condenser dielectric. Thisis not unlike the explosion which occurswhen the air pressure in the tank exceedsa certain critical palue. Both of the ex-plosions may be disastrous, and the dam-age resulting would depend on how muchwork had been done in charging the con-denser or in pumping up the tank.

Knowing that the pressure in eithermay be made too great, we assume thatthe condenser is used within such limitsthat charging and the pumping stop be-fore any disastrous explosion takesplace.

Suppose the two platescal condenser be joined with a wire. Atthe instant the juncture is made there isa sharp spark. The condenser has beendischarged. Both plates are, now at thesame potential pressure. Before the sparkone of the plates was probably at groundpotential; after the spark both are thenat ground potential. While the dischargeof the condenser seems to take place in-stantaneously, actually it takes sometime for the discharge to be completed.

A Violent Rush

Now suppose that the stop cock whichheld the air in the tank be opened. Thecompressed air will rush out. At firstthe rush is violent and later less so. To-ward the end of the air discharge thereis just a feeble movement of air fromthe tank to the open air. The dischargeof the condenser takes place in the, samemanner, rapidly at first then more slowlyuntil there is only a very feeble electriccurrent flowing in the connecting wire.

The electric discharge is much morerapid because the connecting wire be-tween the plates offers less resistance tothe electric current than the tank outletoffers to the current of air.

When the air tank has been discharged. the pressure inside the tank is the same asthe pressure in the open air. One mightcall the pressure in open air atmosphericpotential.

A condenser can be charged in twoways depending on the direction thecharging battery is connected. In oneconnection the ingrounded plate is givena potential higher than the potential ofground. In the other the ungroundedplate is given a lower potential thanground.

Likewise the air tank can be "charged"in two ways, depending on the arrange-ment of the valves on the pump. The aircan be forced into the tank, thus makingthe pressure inside the tank greater than

atmospheric pressure. The air also canbe sucked out of the tank, thus makingthe pressure in the tank less than atmos-pheric pressure.

Same Law for Both

Electricity can flow into a condenseronly until it is fully charged. The amountof electricity that can be forced into thecondenser depends directly on its ca-pacity, or electrical size, and on the elec-trical pressure, or voltage,- The amountof air that can be forced into an airtank depends directly on the size of thetank and on the pressure exerted by thepump. The two are thus closely analog-ous. If Q is the quantity of air or elec-tricity, C the capacity of the tank or thecondenser and E, the electrical or thehydraulic pressure, then in both casesQ equals CE.

In Fig. 1 A is shown a condenser abone plate of which is grounded. A charg-ing battery of voltage E is connected sothat the potential of the ungrounded plateis E volts lower than ground potentialwhen the condenser is fully charged.

In Fig. 1B is the hydraulic analogue.The "grounded plate b" is now simply theoutside of the tank. The "ungroundedplate a" is simply the inside of the tank.The battery of voltage E is replaced witha pump P. The stop cock k is simplyinterposed between the tank and thepump so that the charge will remain inthe tank when the pump is removed.

Direction of Flow

The flow of alternating current in andout of a condenser can also be illustratedwith the same hydraulic analogy. It isshown in Fig. 2, A and B. The batteryof voltage E has now been replaced witha source of alternating emf of effectivevalue E. The stop cock k has been re-moved from the hydraulic analogy andit is assumed that there is no valve in thepump. When the piston moves one waythe air is sucked out of the tank andwhen it moves the other way the airis forced into the tank.

Since in A Fig. 2 one plate of the con-denser is grounded the potential of thatplate cannot change. But that of theother changes with respect to that ofground in accordance with the emf ofthe generator. The plate A is eitherpositive or negative and the electricityflows in the connecting wire and gener-ator either as shown by the arrows orin the opposite direction. No currentflows across the space between the plates.But there is a pressure across it.

In B Fig. 2 the air flows in the direc-tion that the piston moves. When thepiston is out the air flows out, and thepressure in the tank becomes less atmos-pheric; when the piston moves in theair flows in, and the pressure in the tankbecomes higher than atmospheric. Thusas the piston oscillates there is an alter-nating air current flowing in and outof the tank. Likewise there is an alter-nating air pressure which either tendsto burst the tank open or tends to crushit in.

What Current is

An electric is only the rate at whichelectric quantity is transported fromone point to another. It may bemeasured in the outside circuit or it maybe measured as it is withdrawn from thecondenser.

The current is the same at every por-tion of the circuit no matter how wideor how narrow the conductor may be.The same holds in B Fig. 2, or in thecase of a river. The air current is thesame in the connecting pipe betweenthe piston and the tank as it is in thepiston chamber or in the tank.

January 21, 1928 RADIO WORLD 21

Radio Hour BIG DISCOUNTSThe $67,000(Continued from page 11)

the fine playing of the orchestra are sobadly distorted before Bound Brook,N. J., sends out Chicago's best.

There is much to be done in bringinglive transmission up to the quality stand-ards of radio over long distances.

The Words and MusicBefore Carlin, at the WRAF studio,

been listening to Carlin with earphones.had introduced Rogers, the comedian hadRogers in his usual amiable voice andway began:

-Hello, folks! I'm the town crier!"He continued:"This is a cinch of a job Dodge Broth-

ers is giving me. All I got to do is standhere and talk. I got all the movie folksaround me here, all of 'ens. There's BenTurpin, Jack Barrymore, Mary Pickford,Douglas Fairbanks and fifteen others-they're all right around me here, withinfifteen blocks, and if I only knew theirtelephone numbers they'd all be sittingright Isere at the fire with me. Say Ioughtn't to mention fires. They don'tneed any fires in California. By the way,all the movie stars out here are makingNew Year's resolutions and taking newwives. It's a question which they're go-ing to drop first."

This comment came from a man deep-ly devoted to family life and who spendsevery available minute with his wife andtheir children.

Rogers continued:"You know I just came up from Mexico

where I have been an Ambassador forCal. Some of our Mexican friends aregoing to hear this stuff."

Thereupon Rogers spoke a few wordsin Spanish for the particular benefit offolk across the Mexican border. HisSpanish pronunciation seemed only fairto one who studied the language twentydays, twenty years ago, and had heard solittle of it since that he had begun todoubt its continued existence. Rogers'"buenos noches" and "estados unidos"came over well but the other Spanishwords sounded blurred.

(Continued on nc.rt page)

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Take Your Choice of 7Other PublicationsFor NEW RADIO WORLD Subscribers Ordering NOWRadio World has made arrangements-To offer a year's subscription for any one of the following publications with on year'ssubscription for RADIO WORLD-RADIO NEWS or POULAR RADIO or SCIENCE AND INVENTION or BOYS' LIFEor RADIO DEALER or RADIO (San Francisco) or RADIO AGE.

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22 RADIO WORLD January 21, 1928

Good Back Numbers ofRADIO WORLD

The following Illustrated articles haveappeared In back Issues of RADIO WORLDIn 1927.

MAY 21.-Part I of a three-part articleon the Victoreen Portable receiver, byCapt. P. V. O'Rourke. Data on the newRaytheon cartridge.

MAY 28.-A three -tube reflex, using aspecial low pass filter system, by EdgarB. Francis. Part II on the Victoreen port-able receiver with layout data, by Capt.P. V. O'Rourke.

JUNE 4.-Part HI of a three-part articleon how to construct an efficient portableVictoreen Super -Heterodyne. by Capt. P.V. O'Rourke. A complete discussion onthe RCA AC tubes.

JUNE 18.-The six -tube Ecluamatic, aneutralized two -stage tuned RF, three.stage AF resistance coupled set, by Her-bert E. Hayden. How to get the lownotes with transformer or impedance AF.by Dennis J. O'Flaberty.

JUNE 25.-The Lindbergh Plane Speak-er, an excellent cone _ type reproducer, byHerbert E. Hayden. A tube and set tester.by Herman Bernard.

JULY 2.-The Planofier 7, single controlsuper -sensitive set using resistance AFby R. F. Goodwin and S. S. Bruno. Dis-cussion on the new Freshman Equaphase,by Robert Sagala. Data on the six typesof units used for loud speaker operation,by J. E. Anderson.

JULY 9.-How to build a DC A supplywhere the line voltage is 220 or 240. byFrank Logan. Important data on RFchoke coils, by Horatio W. Lamson.

JULY 16.-How to use a voltmeter asmilliammeter, by D. Barretti. How tobuild a 4 -tube, 2 -control regenerative por-table set.

JULY 23.-Building a 7 -tube Super foryour auto, using Victoreen IFT. by JohnF. Rider (Part 1). How to build a 6 -tubeneutralized set, using three tuned RF.two transformer AF, by .john F. Rider.Inside dope on motorboatmg. by J. E.Anderson.

JULY 30.-A 5 -tube standard TRF setadapted to AC operation by the use of theORS 400 mill rectifier tube, with the aidof series filament connections, by RFGoodwin and S. S. 'Bruno. Shielding the11 -tube Melo-Heald Super -Heterodyne re-ceiver, by Clifford Denton. Part H ofthe two part article on the Super in theauto by John F. Rider. How to controlvolume in AC sets by D. Ferrup.

AUG. 6.-A three -tube regenerative por-table with portion of the cabinet as thespeaker, by M. j. O'Reilly. The CashboxUnitune, an ingeniously contrived four -tubequality receiver by Wendell Buck. Howto use AC tubes by C. T. Burke.

AUG. 13.-Hints on constructing a por-table set, by Herbert E. Hayden. A seven -tube, two -control AC operated receiver byCapt. P. V. O'Rourke. Obtaining the Cbias in an ABC unit, using the BA Ray-theon 85 mill tube.

AUG. to.-The Four AC, a four -tube re-generative set employing AC tubes. TimTurkey's argument on why rheostatsshould not be used as volume controls. TheDrum Powertone, a five -tube single con-trol set, using resistance coupled audio.

AUG. 27.-Part 1 of a four part articleon building the 1 -Dial Witz, a single con-trol. voluminous selective 5 -tube set, byA. Irving Witz. A detailed explanation ofthe exponential type of horn by H. B.Herman. Details on the revolutionaryReisz condenser type of speaker. Con-structional data on a special 5 -tube, 2 -dialregenerative set, with three stages of AF,by Tim Turkey.

SEPT. 3.-Part I of a four-part dis-cussion on the new 1928 Victoreen Uni-versal, a super -sensitive 8 -tube Super -Heterodyne, by Capt. P. V. O'Rourke.Complete data on the three types of phono-graph pickups, by j. E. Anderson. PartII of the 1 -dial Witz, wiring hints em-phasized.

SEPT. 10.-The Puratone AC set, a 6 -tube duo -control receiver, using AC tubes,by R. F. Goodwin and S. S. Bruno. Part11 of the 1928 Victoreen Universal, dis-cussing the placement of parts. Part IHof the 1 -Dial Witz on the special place-ment of the coils.

Any Copy 15c. Any 7 copies, $1.06 Allthese 16 copies for $2.00, or start sub-sription with any Issue. Any 8 of thesenumbers sent as premium with NEW year-ly subscription. No other premiums al-lowed. RADIO WORLD, 145 West 45thSt., New York City.

The $67,000 Program(Continued from preceding page)

Rogers then returned to English, aswill be obvious:

"By the way, I have a great surprisefor you folks. I want to switch you inon Washington. I want to introduce ourpresident, Cal Coolidge."

Now Rogers continued by making be-lieve President Coolidge was talking. Toachieve this impression-that is, -the im-pression that Rogers was making be-lieve-he adopted a stage type of DownEast accent, which does not take intoaccount the effect of a college education

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on nasalness. Four years in the WhiteHouse are not to be compared with fouryears at Amberst with Dwight Morrow.Rogers' way of "doing" Coolidge fittedthe occasion icely, for it was all for funand fun for all; only the New Englandersmay have had not so easy a time under-standing what Coolidge was supposed tobe saying.

Rogers then reported on the state ofthe nation, as if Coolidge really werespeaking. (I stress the fact that it reallywas not Coolidge, to avoid 1. -correspond-ence).

Rogers always can be relied on to fillout his part on an occasion and in theVictory Hour he simply filled out hispart. His humor was not "there" butwith enough puns and- natural goodsport he saw the thing through. He hasdone much better. As Coolidge he said:

"You know, the nation is in a hole,but I think the nation is perfectly allright as a whole." When you see thisin type you way make a sour face at itbut when you hear it with your familysurrounding you, why you keep painfulsilence. Rogers (as Coolidge) said Con-gress was in session to spend the moneySecretary Mellon had saved

"It would have been cheaper to havehad the Congressmen stay at home," hesaid, "and let the Government send eachof them the pro rata of the money bymail."

On farm relief he said: "Plenty of rainand bigger crops are better than all theMcNary-Haugeni sm." (See next page)

End Radio BothersKNOW what's wrong when your radio set isn't working right?

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He tells in plain words and illustrations how a set is made, whatthe parts are called, what are the few usual troubles and how tofix them. Then he lists 103 troubles that sometimes happen andtells how to detect and fix each one.

The book is a regular cyclopedia of radio information-only it's in a language anyonecan understand. Read it five minutes and you'll know more about radio than you everdreamed of.It will save you many a repair man. It will save you hours of guessing and fussing andfuming. It will help you to keep the tone of your set always sweet and strong. It willkeep you from losing many programs. And, best of all-IT WILL MAKE YOU STOP SWEARING-MUCH TO THE SURPRISE OF YOURFAMILY-because radio repairs are expensive. Why hire them done when you can easily(earn how to keep your set from needing them?

All It Costs Is $1Send cash with your order and you get also a Dictionary of Radio Terms and the latestlist of Radio Broadcasting Stations with call letters and the new Federal Radio Commissionwave lengths. Send your dollar today while the copies last.

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months, for which

January 21, 1928 RADIO W ORLDIt was enjoyable to listen to Rogers'

nonsense. You could forgive the poorpuns and strained humor that crept in attimes because you realized he is over-burdened with this type of work, and isentitled to off moments.

Rogers introduced Whiteman. Thencame "The Rhapsody in Blue," well done,by piano and wind instruments espe-cially.

Rogers next discussed the artists whowould appear individually, describingthem as "the three outstanding men oftheir lines in the world." He mentionedFred Stone by name first-and also byfirst name, but later-and said of him:

"The finest actor on the Americanstage and the best example of a man."Rogers complimented Dorothy Stone, too,and introduced father and daughter,Dorothy sang "True Blue," of which shewrote the words. She was assisted bythe Criss Cross Four (not a car) Dorothysaid of the song:

"If you like it, I wrote it; if you don'tlike it, daddy wrote it."

Stone later disclosed Dorothy's agethus:

"She's 20 years old in her stockingfeet."

Stone sang "Chinese Song" from "ChinChin. This couplet was caught by yourstruly:

"Di silli lilli lei Mu;Yay noisy louk hoo."The punctuation may not be correct.

The second word positively is.Stone then adverted to the topic

broached by Rogers-the model familylife of all the Stones.

"I have often been asked," said the

Everybody's Talking About ItThere's a wealth of reliable, boiled -

down, and interesting informationin "Resistance the 'ControlFalse' of Radio." Simply writ-ten-clearly Illustrated. Thisvaluable handbook on resistancein radio is worth dollars-sendonly 25 cents for your easy.

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Subscribers : Look at theExpiration Date on

Your WrapperWe do not like to take your name from

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RADIO WORLD145 West 45th Street, New York City

great comedian and man, "why I permitmy children to go on the stage. Be-cause I love my profession, and the stageneeds just such girls as mine. If every-body respected his profession as much asI do mine those professions would prog-ress more than they do. I gladly give mydaughters to the stage because the stageis a vehicle for public service, side byside with every other form of entertain-ment. Good, clean, wholesome amuse-ment is, and always will be, a necessity."

InsideInformation

In buying radio tubes outside appearantes count for nothing.An ordinary test shows only that thetube is operating-it cannot tell you thequality of its performance, nor how longit will wear.But in making CeCo tubes we makesure IN THE PLANT that the qualityand wear are there before any CeCotube is released to the trade or public,You never gamble when you buy CeCo.They are as reliable as a fine, expensive,American -made watch-as truly a pro-duct of engineering skill and care asthe best automobile built today. Yetthey cost no more!Buy CeCo and be sure of results -certain of full value for your money.Ask your radio dealer to help you selectthe types of CeCo best suited to your set.

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HERMAN BERNARD, managing editor ofRadio World, discusses radio topics of popularinterest every Friday at 5:40 P. M. from W BS,348.6 meters, the Gimbel Bros. station la NewYork City. Listen in.

The Big Thrill ofDX, and at very

Small Cost to YouEverybody who owns a radio set likes to

tune in far -distant stations now and thenbecause not only is there a thrill in hearinga voice or instrument thousands of milesaway but one verifies the fact that he hasa powerful receiver and that it is in goodcondition, if it is able to pick up theseweak signals. Now that the broadcastingstations are more suitably distributed as towavelength or frequency, fans are inbetter position to tune in distance. 13e -sides, the weather is in their favor thesedays. But what kind of a set shall beused? You know very well that if theset can tune in distance once in a while,you can develop sufficient skill to make ittune in far -distant stations very often,virtually every night. Then when youhave visitors you need not boast aboutthe DX qualities of your set but simplytune the receiver and let them listen tostations thousands of miles away. Youmust be sure to have a receiver capableof responding to your distance -getting de-sires. You also want this set to have de-lightful tone quality, so that your owncritical ears cannot detect even a singleflaw in the reproduction. Indeed, evenmusic lovers who may be guests at yourhome will comment admiringly upon thebewitching tone of your receiver. Thenyou know you have something real. Theability to get distance and to reproduce theoriginal music without distortion dependslargely on the circuit design, and you willfind that the Diamond of the Air, eitherthe 4 -tube or the 5 -tube model, will liveup to your highest expectations. Howare you going to know which to build?Carefully inspect the textual data as wellas the blueprints that fully expound thetheory, operation, characteristics and am-plification of these two outstanding receiv-ers that differ principally in the type ofaudio amplification.

The 5 -Tube DiamondCan be constructed in a couple of hours.The authorized blueprints that make thisspeed and efficiency possible are just offthe press and will be shipped at once, to-gether with the new booklet of full textualexposition of construction, including thewinding of coils, how to connect terminals,what values of condensers and resistors touse, etc. The receiver consists of a stageof tuned radio frequency amplification, aspecially sensitized detector, first stage oftransformer audio and next two stages ofresistance audio. It is easily adapted toplaying phonograph records through theset and on your speaker. Get acquaintedwith this new delight.

The 4 -Tube Diamondrepresents the most that is obtainable fromfour tubes. A stage of tuned radio fre-quency amplification, a specially sensitizeddetector and two stages of transformercoupled audio. Follow the blueprint toamazing success. Build the set from partsyou have. Full instructions cover utiliza-tion of such apparatus. Thousands are

eager to build an economical set of sur-passing performance and amazing achieve-ment and this one is the most economical,the most scientific, and the least expen-sive in cost of parts and upkeep. Workssplendidly from batteries, either type 99or type lA tubes, and can be used withA and B eliminators, power packs, etc.,with great success.

Look over both of theseblueprints and read the text in both camsbefore choosing the receiver you are tobuild. - _

Guaranty Radio Goods Co.145 West agth Street, New York City

Please send me one newly -printed officialblueprint of the 5 -tube Diamond of theAir, one newly printed official blueprint ofthe 4 -tube Diamond, and the textual datagiving full directions for constructing thesesets. Enclosed please find 50 cents to de-fray all expense.

Name

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RADIO WORLD January 21, 1928

I

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Simply remove from carton, screwto pole and erect on roof-outsideof window-or :on porch.The moment you hook to it, you'llget a gratifying surprise in moredistant stations and sharper, clearertuning. And it's -up to stay withoutdanger from snow, ice, wind orcorrosion.Diameter, 14 inches; height, 14%inches; weight, 41A pounds, packedfor complete shipment.Pole, 15 inches high, furnished'witheach order; also mounting screws.Nothing needed except lead-in.

GUARANTY RADIO GOODS CO.,145 WEST 45th STREET, N. Y. CITY.Please send me at once, one COIL-TENNA,for which I will pay the postman $4.00, plus afew cents extra postage, on receipt.

NAME .

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CITY STATE

"Double R" BRETWOODPanel Meters Rugged and

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eDUBES last longer when the1 voltages are right. The panel

meter is just the thing you want forthat. If you are discriminating youwant the finest tone quality. A 0-50milliammeter in the plate circuit ofthe last tube serves that object ad-mirably. Mount the meter on thepanel.

You will be delighted at the en-joyment that will be afforded by theuse of a panel meter. The DoubleR meters are sturdily built andaccurate, yet priced very modestly.

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All you have to do is to let usknow what meters you want. Orderby catalog number, which appearson the left in the list printed here-with. When the postman deliversthe meter you pay him the pricelisted below, plus a few cents post-age. Then you will put your meterinto action and enjoy the fruits ofyour wise buy. Note AC meters fornew AC tubes.

DC PANEL MILLIAMMETERSPrice PrIoeNo. 311-0-10 mil- No. 390-0-100 mil-

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AC PANEL VOLTMETERSPriceNo. 351-0-15 volts $2.21

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Please send me Double R meters catalogue num-bers for which I willpay the postman on receipt of meters, plus a fewcents extra for postage. These meters are to bereceived by me on a 5 -day money -back guaranty.

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Variable Grid LeakDe Luxe Model

BETTER BY FAR, than any fixedleak in the detector circuit is theBretwood Variable Grid Leak.

Why?Because it allows adjustment of grid

voltage to maximum sensitivity for re-ception of far -distant signals, while per-mitting faster discharge of electrons whenreceiving strong local stations, thus pre-venting distortion due to this. There-fore, a Bretwood Variable Grid Leakmeans more miles plus best possible tone,without any extra tubes. A patentedplastic and fool -proof plunger insure per-manence in holding any desired resistancesetting from .25 to 10 megohms, as wellas the very long life of the leak itself.As no grid leak can function any betterthan its grid condenser, be sure thatyou employ a leak -proof Bretwood BulletCondenser of mica dielectric and of .00025mfd. capacity. This precision product isaccurate to within one -tenth one per cent.

FREEhookups are supplied with each purchase.DON'T SEND A SOLITARY CENTThe Bretwood Leak may be baseboard or panelmounted. Works the same in any position. Nofluid used.

Guaranty Radio Goods Co.,145 West 45th Street, N. Y. City

Please mail me at once one New and Improved1928 Model De Luxe Bretwood Variable Grid Leakwith one Bretwood Bullet Condenser attached, forwhich I will pay the postman $2.25 on receipt. Bothmust be the genuine Bretwood articles, importedfrom England.

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