ILLUSTRATED Every Week A NEW METHOD OF POWER … · 2019. 7. 17. · liArttua 15 CENTS ol. 9. No. 4. ILLUSTRATED Every Week THE NEW 1 -DIAL 5 -TUBE POWERTONE SMOOTHING OUT CONTROL

liArttua 15 CENTS

ol. 9. No. 4. ILLUSTRATED Every Week

THE NEW 1 -DIAL5 -TUBE POWERTONE

SMOOTHING OUTCONTROL OF TICKLED

A NEW METHOD OF POWER BOOSTINGHow to Build a 5- Tube Super -Heterodyne Set

CODE OF ETIQUETTE FOR LISTENERS -IN

--IE UTMOST IN CONVENIENCE !-A switch in a box, secured to the floor, under the table permits Miladyto turn the set on or off with no more movement or effort than summoning the marl

RADIO WORLD April 17, 1926

Kits may come and kits may go-but the 1926 Model

"Diamond" Kit $35is growing more popular every day. There's a reason!

I be parrs obed thu boxed and sealed kit ar e 431 the best obtainable. They are matchedand perfectly balanced to give the best possible results in this circuit. Each Kit bears theseal and signature of Herman Bernard and the approval of Sidney E. Finkelstein, two ofRadio's foremost engineers. This is your guarantee of a perfect receiver.

Bruno 99 or 55 R FTransformer S3.00

For those that havesome parts already we

can recommend the

Basic D:amond

Kit $20.00The contents of this Kit canbe used for any four or fivetube circuit as well as theDiamond. It contains: OneBruno "99" tuning coil; oneBruno "99" R.F. coil; threeBruno vernier dials; two "23"Streamline frequency con-densers and one light switch.To be genuine each Kit mustbear the seal and signature ofHerman Bernard. Neatlypacked ready to assemble.Shipped anywhere the day theorder is received.

Bruno "99" TuningCoil 55.50

Bruno Brackets, perpair S1.00

B -C -L Dials 59c Bruno Light Switch price (without Bulb) 7k

Send 50c in stamps or M. 0. for I6 -page booklet with Blueprint on theDiamond of the Air

B.C.L. RADIO SERVICE COMPANY 221 FULTON ST.NEW YORK, N.Y.

RESULTSReaders report on their ex-

periences with sets built fromhookups published in RADIOWORLD. Address Results Editor,RADIO WORLD, 145 West 45thStreet, New York City, and sendphotographs of sets, if possible.

RESULTS EDITOR:Using the article that appeared in the

November 21 issue of the RADIO WORLD, Ihave constructed the 8 -tube DX Super -Heterodyne. I wish to state that for dis-tance, selectiveness, volume and clearnessof tone, it has everything beat that I haveheard so far, and I have heard some of thehighest priced sets.

In this construction I have used thetwin .0005 mfd. condensers, manufacturedby the General Radio Company; one.0005 mfd. condenser manufactured by theMarco Co. the intermediate frequencyin -put transformer and the three interme-diate transformers are of the Remler 610and 600 type, while the oscillator is theRemler 620 coupling unit. The coils usedare the General Radio 277-D with the twoadditional turns added to the secondaryas recommended by the manufacturers.

California, Texas, Florida, Cuba, Canadaand Atlantic City stations come singing instrong over the loud speaker, without theslightest distortion, be the note high orlow. The words are not yet coined, thatcan express the pleasure in listening tosuch reproduction.

LESTER C. GELSON.Castle Shannon, Pa.

* * *

*

RESULTS EDITOR:I have recently completed the 4 -Tube

Amsco-Aero Receiver, described by Her-bert E. Hayden in the Nov. 14 and 21issues of RADIO WORLD and it is withoutquestion the greatest receiver that I haveever seen. The readings on both dialsalways are alike. I have received sta-tions located in every portion of the coun-try. The selectivity is all that could bedesired of any receiver. I live about 2,4miles from stations KSD, WIL andWSBF and find it very easy to tune indistant stations. All the stations areheard on the loudspeaker with plenty ofvolume to spare.

I wish to thank Mr. Hayden for thedesigning of this remarkable set.

DR. R. J. THOGMORTON,4049a Botanical,

St. Louis, Mo.

RESULTS EDITOR:I have been a steady reader of RADIO

WORLD and must say that it is a realmagazine for the radio experimenter. Ihave constructed the 1 -Tube Loud Boyreceiver described by Herman Bernard.in the Feb. 6 issue. Using only one tube,which is of the 99 -type, I am consistentlyreceiving stations 50 miles distant on theloudspeaker. I am surrounded on threesides by high tension power lines, butstill all the Chicago stations cnme in onthe loudspeaker. All the connectionswere brought directly to the posts. Thisdid away with soldering.

GEORGE A. WOLFORD,660 Mott Ave.,

Waukegan, Ill.

* * *

RESULTS EDITOR:I have built the 1926 Model Diamond

of the Air and am well pleased. The vol-ume and the quality are marvelous.

J. A. McBAIN,125 Viola St.,St. Paul, Minn.

RADIO WORLD[Entered as second-class matter. March. 14.7. at the port office at New York. N. Y.. ender Act of March 3. Id791

A Weekly Paper Published by Hennessy Radio Publications Corporation from PublicationOffice, 145 West 45th St., New York, N. Y. ,,f)W,..` R::`, Phones: BRYant 0558 and 0559

Vol. IX. No. 4. Whole No. 212 April 17, 1926 15c per copy, $6.00 a year

The New 1 -Dial PowertoneA Set With a Lot of KickBy Capt. P. V. O'Rourke

HE electrical circuit diagram of theimproved Powertone is shown in Fig.

1. In the old Powertone, fixed condenserswere in shunt to the plate and negativefilaments of the radio frequency and thedetector, so as to obtain greater signalstrength and also a higher oscillatory ac-tion for these tubes. However, it wasfound that when this was done unless theutmost care was taken in placing the coils.the receiver became very unstable anddifficult to operate. Consequently a sys-tem of neutralization was sought, whichwould give the same volume as with thefixed condensers. The coil, L5, which isnothing more than a rotary coil of asimple 3 -circuit tuner, when its turns wereshorted and placed in conductive relationto the secondary of the interstage coup-ling radio frequency transformer andthen varied so as to obtain the same actionas if the leads of the coil were reversed,the capacities of the tubes becomeas if neutralized.

The volume obtained when using thismethod is tremendous. The amplifierportion of the circuit remains the same,e.g., one stage of transformer couplingand two stages of resistance coupling.Only one ballast resistor is used to controlthe filament action of the tubes. Thisdoes away with the two rheostats, withwhich the oscillatory action of the RFand the detector tubes was possible. AC battery is also employed. This reducesthe tremendous amount of milliamperesusually drawn by the plate of the lasttube, using resistance coupled amplifica-tion.

The tuning is done solely again by thedouble condenser, Cl. This varies thecapacity equally for its two sections, al-though there is only one motion. Thisis due to the common rotor. If this re-ceiver is made with the coils, and otherparts are specified, there need be notrouble about failure to get the same fre-quency for both sections, at a specifieddial reading.

The two radio frequency coils are of thesame construction and consist of the

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FIG. 1.The special feature of the 1 -Dial Powertoneto the secondary of the interstage couplerand balancing agent, bringing out full, deepthe excellent quality of the received signal

same number of turns, as in the old modelPowertone, thus, the primaries, LI andI-3, consist of 10 turns; the secondaries,L2 and IA, consist of 53 turns; a 2%"diameter and 4" high tubing being used.No. 22 DCC or No. 24 S over C wire isused. The rotary or balancing coil, con-sists of 40 turns of No. 26 single silk cov-ered wire, wound on a tubing 1" in diam-eter and 2" high. This of course is placedinside of the secondary winding of thesecond RFT.

The panel layout is somewhat changedby the absence of both rheostats and thepresence of the light switch. A 7x18"panel is employed. The shaft for thecondenser is placed in the center. Theshaft for the tickler knob takes the placeof the rheostat controlling the. filament ofthe detector tube. That means that thisRFT is placed here also. The light switchmay be placed over the center dial, or1%" to the right of and 2" from thetop of the panel. The switch is under-neath the shaft of the variable condenserand 3/4" from the bottom. The socketstrip is mounted on angle brackets. Thesocket holding the RF tube is at the left,the detector socket comes next, followed

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FIG. 2.A bottom view of the subpanel or socket shelf, helpful in locating theparts. While the audio transformer is placed underneath, if a large sizedone is used it will not fit in, so in that case put it on top of the shelf.Brackets support this shelf on the front panel. This diagram is 4 scale.

oMB-A-

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(WM

, new model, is the rotary coil connected. This coil serves as a volume controlvolume. The audio amplifier preservesand works splendidly on horn or cone.by the three audio sockets, the trans-former stage being first. The resistors,fixed condensers and transformer, are allmounted on the bottom. With the setface up, only the shells, the two phonetips and the antenna and the ground postsare seen.

Bring all the F plus posts together, andbring to one terminal of a filamentswitch and to one terminal of the filamentof the pilot light, L, point 2. The otherterminal of the switch (1) goes to the Aplus B minus post. Bring the F minusposts of the five tubes (including theRF, detector and the three AF tubes)to one terminal of the ballast resistor, RI.Connect other terminal of resistorto one terminal of the filament light ter-minal of the pilot light, L, point 3, and tothe A minus post. Now connect the be-ginning of the primary winding, Ll, to theantenna post. Bring the end of this wind-ing to the ground post. Bring the begin-ning of the secondary winding, L2. to theA minus post, to the common rotor of thedouble condenser, CI, and to one terminalof the shorted tickler winding, LS. Bringthe end of the secondary winding to thestationary plates of the condenser, knownas section Y and to the G post on socket1. Bring the other staton, section Z, to theend of the secondary winding of the sec-ond RFT and to one terminal of a fixedgrid condenser, C2. The other terminalof this condenser goes to the G post onsocket 2 and to one terminal of a fixedleak, R2. The other terminal of this leakgoes to the F plus post on the samesocket. The beginning of this secondarywinding, L4, goes to the same connectionthat the beginning of the secondary, 12,went. The beginning of the primary, L3,goes to the P post on socket 1, while theend goes to the B plus RF amplifier lead.

4 RADIO WORLD April 17, 1926

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LIST OF PARTSOne RFT, L1L2.One 3 -circuit tuner, L3L4L5.One .001 mfd. variable condenser, two

sections, each .0005 mfd., Cl.One ballast resistor, RI.One .00025 mfd. grid condenser, C2.One 2 megohm grid leak, R2.Four .1 megohm resistors, R3, R4, R5,

R6.Two .006 mfd. fixed condensers, C3, C4.One AFT.One 4" dial.One pair of phone tip jacks.One pilot light and switch, LS (Bruno).One 2" knob for tickler.Five sockets.One socket strip, 16x232".One 7x18" panel.Two brackets.One battery cable.Accessories. Five storage battery tubes,

one storage battery, two 45 -volt B bat-teries or a B eliminator, one speaker, 100feet of aerial wire, 50 feet of lead-in wire,ground clamp, cabinet, connecting wire,etc.

The P post on the AFT goes to the Ppost on socket 2. The B post goes to theB plus detector lead. The G post on thisAFT goes to the G post on socket 3. TheF post goes to the A minus post. Oneterminal of the fixed resistor, R3, goes tothe P post on socket 3. The other ter-minal of this resistor goes to the B plusamplifier lead. The P post on socket 3,also goes to one terminal of the fixedcondenser, C3. The other terminal of thiscondenser goes to the- G post on socket4 and to one terminal of the fixed resistor,R4. The other terminal of R4 goes toA minus. The P post on this socket goesto one terminal of C4 and to one terminalof R5. The other terminal of R5 goes tothe B plus amplifier lead. The otherterminal of the fixed condenser, C4, goesto the G post on socket 5 and to oneterminal of R6. The other terminal ofR6 goes to the C minus post. The pluspost of this battery goes to the A minus.The P post on the last socket, 5, goes toone tip jack, while the other tip jack goesto the B plus amplifier lead.

(Continued next week)

GAMBY ON TOURGamby, probably the only dancer in

the world famous on the air, is now ontour in vaudeville with her own company.Mlle. Gambarelli appeared for severalyears consecutively on Broadway as thehead of the ballet of a large motion pic-ture theatre. It was while there that Roxyintroduced her to radio listeners.

CAPTURING THE ENEMYWifey: Fancy you buying that loud-

speaker! The people underneath worryus nearly to death with theirs!

Hubby: Don't worry, dear. This is it!-Passing Show.

NEW CRYSTAL HOLDERMuch promise is held forth for au 1111 -

proved crystal holder invented at theNaval Research Laboratory.

TELEVISION, HURRY UP!It is too bad listeners may not see the

gorgeous new uniforms of the Navy Bandwhen it broadcasts front Washington.

HEADPHONES REPLACE FEZZESThe Constantinople Chamber of Com-

merce has decided to get into the game bypurchasing wireless apparatus so that itmay receive information regarding worldmarkets.

April 17, 1926 RADIO WORLD 5

The Power Booster Set

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FIG. 1.An unusual method of employing the acceptor method of tuning (C3. L4), although at first blush it looks like a rejectorwavetrap, is shown above. The amplification is at least doubled and selectivity enhanced greatly. The winding LS is an

important factor in the system.

By Mary C. DrewTIE rejector wave trap, consisting of afixed coil tuned by a variable con-

denser, the coil being in inductive rela-tionship to some winding of the receiverproper, is familiar to all. But its possibili-ties and variances are not so well known.

-For instance, under certain conditions,this trap system functions as an acceptor,not as a rejector, and improves the selec-tivity to a marked degree, while boostingthe power of the set, too. Thus even astage of tuned radio frequency amplifica-tion preceding a non -regenerative detectortube is made to function with surprisingefficiency. How this is done I shall de-scribe.

The heart of the circuit is the tunedcircuit L4C3 and the primary winding 1.5of the interstage coupler. L4C3 is theseeming wave trap rejector circuit. Underordinary conditions it would reject, butit is made to accept by virtue of the oscil-latory tendency of the radio frequencytubes, particularly tube 1. It delivers cur-rent, instead of. extracting it. A detectortube may be rated as a radio frequencytube, also, since it performs both func-tions.

The Power Booster Coil.The coil system, L1L2L3194, consists of

windings put on a form in the order sug-gested in Fig. 1. For instance, if youtake a 3%" diameter form, 6" long, youwind the coil as follows: Using No. 24double cotton covered wire throughout,leave a 1" space from top. Put on 47 turnsfor L3. Terminate the beginning and theend of the winding. Allow a -foot or soexcess wire for connections to the set inevery case. Now leave Xt" space and startwinding the other large coil, L4. This,although tuned by a condenser of thesame capacity as Cl, must have moreturns than L3, hence for L4 put on 55turns. Now 'go back to the 1" space, anddrill an insertion hole for the primary wireyou are about to put on. This hole willbe ,A" away from the beginning of L3,the first coil you wound. Thread five feet,of wire through, from the inside of theform, so that the wire passed through thehole may be wound on the form. As youare moving upward, whereas formerly youwere moving downward in the wiring, put

LIST OF PARTSOne power booster coil, LIL3L4L2.One tuned radio frequency transformer,

L5L6.Two audio frequency transformers,

PBGF.Two 30 -ohm rheostats, RI, R2.One No. 112 Amperite, R3.One light switch, LS.One push-pull switch, SI.One double circuit jack, .11.One single circuit jack, J2.One .00025 mfd. fixed grid condenser, C4.One grid leak, 2 to 9 meg., R4.Three .0005 mfd. variable condensers,

CI, C2, C3.One 7x21" panel.One 7x20" baseboard.Three 4" vernier dials.One 1.0 mfd. fixed condenser, CS.

the wire on in the opposite direction. sothat the net result will be that all wind-ings are in the same direction. This maybe determined easily by assuming thatthe wire terminals are arrows. The liketerminals, for instance, the top ones, of allcoils should point in the same direction,and so will the bottom terminals, ofcourse. The only proviso is that theterminals must be on the same side of thecircumference, and this will be so, sinceonly unit number of turns is used. Drilltwo anchorage holes for Ll.

Now unravel 5 feet of wire and cut thewire from the spool. Bring the wire thatrepresents the end of Ll, the 5 -foot coilalready wound, straight down to K" fromthe end of IA, drill a hole, thread throughand wind the remaining stretch of wireon the form. Anchor the new terminal.The more important coil is now complete,with Ll at top, L3 adjoining it, L4, thepower booster coil, only the winding isphysically separated, so that half of it isat top of coil and half at bottom. Theconnection or continuation is madethrough the inside of the form, called thecore.

The Other CoilThe only other radio coil in the circuit

is L5L6. If .0005 mfd. is used for C2,then on a 314" diameter put 47 turns ofNo. 24 double cotton covered wire for L6.

The number of turns on L5 can not bedefinitely given so as to assure utmostsatisfaction in all instances. Experimentis advisable. The number of turns must.be greater than the conventional 8 or10 -turn primary, hence it is suggestedthat 14 turns be used here, and that theseparation between L5 and L6, instead ofbeing the usual %", be nearer %". Forutter ease of arriving at the correct num-ber of turns for L5 it is suggested thata %" separation be maintained,. as out-lined, and that the 14 turns be put on, sothat turns may be taken off at the endwhere this may be done without affectingthe separation between the two windings.The sole determining factor is the resultin terms of efficiency, hence no one needhesitate removing turns, as occasion de-mands, even unto reaching the 12 or 10 -turn primary if necessary.

Points of InterestTwo interesting points in reference to

this hookup are that the coils in the radiocircuit need not be placed at any sacredangle, but may be in parallel formation,although preferably not close together,and also that the method of connection ofL5 is often vital. Hence if instability de-velops, simply reverse the connections toL5.

It seems hardly probable that instabilitywill trouble any one who builds this re-ceiver, beause the very idea of the powerbooster, the goal that Herman Bernardsought in designing it, was to afford avery satisfactory control of the stability ofa receiver. The system worts out beauti-fully with one stage of RF, as diagram-med, and the selectivity is all sufficient forthe most exacting conditions, such asthose existing in the Borough of Man-hattan. I have been using this set in myapartment on Park Avenue, with WJZ,WHN, WLWL, WMSG, WRNY, WBNYand other stations close by, in fact al-most radio neighbors of mine, and I amnot troubled with interference. If youget it working properly, that is, in ac-ceptor style, I assure you that you willhave a wonderful receiver. And to makeit work that way requires no further in-formation than what I have imparted sofar.

As for the theory of the power booster(Concluded on page 15)


A 5 -Tube Super Receiver

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FIG 1.THE schematic diagram of the 5 -tube Super -Heterodyne.

By Jasper JellicoeUNTIL very recently the answer to the

popular query regarding the type ofreceiver at home, was, "I have a 5 -tubeset." The exact type of receiver was notasked. However, the trend is to cite thespecific type. If you have a 5 -tube setit may be even a Super -Heterodyne. Sucha circuit is shown in Fig. 1. Crystal de-tectors are employed as first and thesecond detectors. The coupled Hartleyoscillator system is used to produce theoscillations for beating the incoming fre-quency. There are only two major con-trols. These are the variable condensers,Cl and C2. A rheostat, R1, is employedto control the temperature of the filamentof the oscillator tube. One rheostat, R2,is used to control the filament tempera-ture of the two intermediate frequencyamplifiers. The filaments of the amplifiertubes are controlled by the automaticballast resistor, R3. A potentiometer, R4.is connected with movable arm to thegrid returns of the two intermediate am-plifiers, to divide the voltage or bias.Transformer coupled audio frequency am-plification is used.

Coil WindingThe primary of the antenna coil, Ll,

consists of 10 turns, wound on a tubing3%." in diameter. The secondary of thissame coil, L2, consists of 45 turns, woundon the same tubing, with a %" separationbetween the two windings. No. 22 or 24double cotton covered wire is used. Theprimary of the oscillator coil, L3, consistsof 10 turns. This is also wound on atubing 3%" in diameter. Now the gridand the plate windings, L4 and L5 re-spectively, are really like the secondarywinding of an antenna tuner. The turnsare 45. The grid part, L4, consists of 30turns. The plate coil, L5, is made up ofthe other 15 turns. The two windings areseparate, with a fixed condenser between.The long wave (abbreviated LW) trans-formers are of the standard make. Fixedcrystal detectors may be used.

The entire set may be housed in a cab-inet 7x21". The sockets, transformers andcrystal detectors (if not the panel mount-ing type), may be either mounted on asocket strip or on a baseboard. If thebaseboard is used, it should be 20" longand 6" wide. If the strip is to be used, itshould be 20" long and about VA" wide.The two variable condensers should bemounted on the opposite portions of thepanels, with the two rheostats and poten

tiometer lined up in the center in thesame line as the shafts of the condensers.The switch, S, should be placed in exactlythe center and about PA" from the bottom(depending upon the portion used for theplacing of the board or strip). The jackshould be placed in the right hand cornerof the panel.

Hooking up the ReceiverFirst wire the filament circuits. All

the F plus posts on the sockets are con-nected together. This common lead goesto the A plus B minus post on a terminalstrip. One terminal of the potentiometer,R4, carrying the resistance wire, goes tothis A plus lead. The resistance terminalof R1 goes to the F minus post on socket1. The resistance terminal of R2, goesto the F minus posts on sockets 2 and3. The arms of both these rheostats areconnected together. These go to the left -off resistance terminal of R4, the poten-tiometer, to the C plus terminal, to oneterminal of the switch and to the A minuspost on a terminal strip. The F minusposts of sockets. 4 and 5, are connectedtogether and also to one terminal of aballast resistor, R3. The other terminalof the ballast resistor, R3, goes to theother terminal of the switch. The suc-cessive circuits beginning with that of theantenna are now wired up. The begin-ning of the primary, LI, in the antennacoil, goes to the antenna post. The endof this coil goes to the ground. The be -

LIST OF PARTSOne antenna coil, LIL2.One special oscillator coil, L3L4L5.Two .0005 mfd. variable condensers,

C1CZ.Two crystal detectors, CD1, CD2.Three medium frequency transformers,

LW1, LW2, LW3.One .006 mfd. fixed condenser, C3.One 6 ohm, 34 ampere rheostat, Rl.One 6 ohm, ;¢ ampere rheostat, R2.One 400 ohm potentiometer, R4.One 1¢ ampere ballast resistor, R3.The low ratio AFT.One .001 mfd. fixed condenser.One switch.Five sockets.One 7x24" panel and cabinet.Two 4" dials.One terminal strip.One baseboard or strip as per text.Accessories: Connecting wire, five

tubes, A, B and C batteries, etc.

ginning of the secondary winding, L2,goes to the variable plates of Cl and tothe beginning of the primary of the oscil-lator coil, L3. The end of this coil goesto the B plus post on LWI. The P poston LW1, goes to the high potential pointof the crystal detector, CD1. The lowpotential side of the detector goes to theend of the secondary winding, 1.2 and tothe stationary plates of the variable con-denser, Cl. The beginning of L4, thegrid winding, goes to the variable platesof the condenser, C2, and to the arm ofthe rheostat, RI. The beginning of thiscoil goes to the G post on socket 1 andto one terminal of a fixed condenser C3.The other terminal of this fixed condensergoes to the beginning of the plate wind-ing, L5. The end of this winding goes tothe stationary plates of C2 and to the Bplus 45 volt post. The G post on LW1,goes to the G post on socket 2. The Fminus post, here, goes to the F minuspost on LW2 and to the middle post onthe potentiometer, R4, making contactwith the arm.

The P post on LW2, goes to the P poston socket 2. The B+ post on LW2 goesto the B plus 45 volt post. The G post onLW2 goes to the G post on socket 3. TheP post on LW3 goes to the P post onsocket 3. The B plus post goes to the Bplus 45 volt post. The G post on LW3, goesto the low potential side of the crystaldetector. The high potential side of thecrystal detector goes to the P post on AFIand to one terminal of the fixed conden-ser, C4. The.B plus post on LW3, goes tothe B plus on AF1. The G post on thisAFT goes to the G post on socket 4. TheF minus post goes to the minus of the Cbattery. The F minus post of AF2 alsogoes to this same point. The P post onAF2 goes to the P post on socket 4. TheB plus post on this AFT goes to the Bplus 90 volts post. The G post on AF2.goes to the G post on socket 5. The Ppost on socket 5, goes to the top terminalof a single circuit jack. The bottomterminal of this jack goes to the B plus90 volt post. You will note that the platesof the two AF tubes receive 90 volts,while the plates of the oscillator and theintermediate tubes receive 45 volts. TheC battery should be of the 4.5 volt type.

If the intermediate transformers are ofthe shielded type, then they may be placer?parallel to each other. Otherwise placethem at right angles. The oscillator coils.should be paced at right angles to the an-tenna coil.

A I) 1 l) W OR I..D 7

p -I

Smoothing Out the TicklerBy Jackson Lee

SOMETIMES a fan builds a set with astage of tuned radio frequency ampli-

fication ahead of a regenerative detectorand finds that the tickler is critical, ex-tremely so. It should not be, but it is.The reason may lie in poor judgment orlack of knowledge or care, resulting inhigh potential leads running close to-

gether or parallel to one another, e.g.,grid and plate leads. Maybe, besides, thefan has a tickler coil with too many turnsof wire on it. The tickler should haveonly enough turns to produce regenerationon the highest broadcast wavelength, or,even up to 555 meters. In that way thetickler construction is generous to thefeedback adjustment for the lower wave-length levels, and the coil may be reliedupon to produce regeneration at anywavelength lower than any other wave-length on which it produces feedback. Awider dial separation for feedback onthe lower waves is thus enjoyed, andit is a distinct advantage.

Help From a DialOne point not often raised is that any

existing set, where one finds the tickleris too confined in its dial settings, that is,covers the feedback for all useful fre-quencies over only 10 or 20 degrees of thedial, is the cure of this crowding by usinga dial ordinarily designed to convert asemi -circular plate condenser into straightline frequency tuning characteristics. Thisserves convenience, in giving one moreroom on the dial in which to work, and itmay be regarded as alleviative of thecritical condition.

A simple method of smoothing out re-generation control, which works well inmany sets, is that shown in Fig. 1. Thereregeneration really takes place in twotubes, but in a manner that abstracts the"untunability" usually attaching to sucha circuit. It is not to be supposed, fromthis statement, that more distance will bereceived. Indeed, the better practice isto have a nonregenerative tuned RFstage, and put the regeneration only inthe detector tube. But the fact taken forgranted is that a fan has run into sometrouble with this and wants to remedy it.

In Fig. 1 you see the tickler coil T feed-ing back into the secondary L2 of theradio frequency transformer. The feed-back is not from the radio frequency tubebut from the plate of the detector tube.The radio current undergoes a phasechange by virtue of this skip method offeedback. Remember that the 3 -circuitcoil LIL2T comes first, despite T beingconnected to detector plate.

Change Coils AboutTo make the change it is necessary to

remove the coils from their present posi-tion, as they change places. That is, the.3 -circuit tuner is placed first, at left, asyou look at the panel or baseboard front,and, following the first tuning condenserCl, comes the radio frequency trans-former, which previously was first. Theprimary and secondary of the 3 -circuittuner (LI and L2) are connected respec-tively to aerial ground, grid and nega-tive filament. The primary U of the radiofrequency transformer goes to plate andB plus amplifier, while the secondary L4is connected to one side of the grid con--denser, C3, and to positive A battery. Ofcourse the tuning condensers, CI and C2,are connected across the respective sec-ondaries, with stator plates to the gridside of the secondary in each instance.The tickler coil is wired with one terminalto the plate of the detector tube and theother to B plus detector voltage. The

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AFIG. 1.

THE TICKLER COIL is uied in both the radio frequency and detector stages bythe method shown in the diagram. The method is a departure from the conven-tional in hookups, and is suggested by the author as a means of remedying critical

tickler adjustment.amplifier B voltage may be 90, with notmore than 4% volts negative bias on theaudio grids, while the detector voltagemay be any voltage that suits your tastebest, although normally 45 is to be recom-mended for best volume.

Wiring DetailsThe rest of the wiring is orthodox. LS

is a light switch, in which a Mazda orother flashlight bulb is inserted, so thatthe light shines through .the facets of ared "jewel" that is a part of the panel -mounted switch. This particular switchis the master one and if any tubes arealight, the red signal will be there. Turnoff the tubes and the switch light goesout. The other switch, SI, is a toggle orpush-pull switch, also panel mounted,which turns out the audio tubes, in caseyou want to listen in only on the ear-phones front the detector output. T

The tubes are (1), radio frequency; (2),detector; (3), first audio and (4), secondaudio.

Those who desire to build the set denovo may care to wind their own coils, al-though commercial coils are to be prefer-red. Using two forms, each 31/2" diam-eter and 3" or so high, the primaries andsecondaries are wound alike. L3 has 8turns of No. 24 double cotton coveredwire. Terminate this winding. Leave 1/4"space and wind the secondary, L4, whichconsists of 47 turns of the same kind ofwire, wound in the same direction. Thiscompletes the radio frequency trans-former. For the 3 -circuit coil, LIL2T, re-peat the process, and remember that ashaft has to go through the secondary, andmust be attached to the third coil in thisunit, the tickler T, to rotate it. and thisshaft must extend through the panel. Tis wound on a 2a/4" or somewhat smallerdiameter, and if the same size and kind ofwire is used, may comprise 38 turns. Thesecondaries are for .0005 mfd. condensers.For .00035 add 10 turns. Smaller wiremay be used, if desired.

DX and Tuning Out LocalDelight Victoreen Fan

Several weeks ago designerof the Fenway, a 9 -tube Super -Hetero-dyne, with 4 -tube option, in a sportingspirit asked readers of RADIO WORLD tocompare results obtained from the Fen -way with those obtained from the Vic-toreen, an 8 -tube Super -Heterodyne ofentirely different design. His request waspublished in RADIO WORLD and evoked manyreplies. One of them was a prompt ac-ceptance of the challenge by George W.Walker himself, Mr. Walker being themanufacturer behind the Victoreen.Some time was permitted to elapse so thata genuine survey of the field would re-sult. More letters were received boostingthe Victoreen than the Fenway, while fewgave actual comparison of the two sincefew possess both sets. Here is one letterfrom a Victoreen fan. Others from Vic-toreen and Fenway fans will be publishedsoon.Editor RADIO WORLD,

The challenge of Mr. Leo Fenway todetermine the most popular radio, in issueof Feb. 27, has been noticed.

I want to cast my vote for my Victor-een 8.

During the International Test Week Ibrought in Bournemouth, Eng.; Madrid,Spain, Stuttgart, Germany, and Lima,Peru, each of which has been officiallyverified and I have my certificate of audi-

tion from authorized judges.Naturally I am proud of having accom-

plished what so many failed to do. To ac-complish what others gave up as impos-sible is always pleasing.

But there are other features of the Vic-toreen which I consider even more pleas-ing. On ten consecutive nights I heardMexico City and then failed on theeleventh because of a violent thunderstorm. Havana, Cuba, is as easy to bringin as Chicago; Denver is local to me.Stations in Florida, Texas, New Orleans,Atlanta, New York, Boston, etc., comebooming in with ample power and with-out distortion.

My set is located less than a mile fromthe powerful KMOX, "The Voice of St.Louis." I have no trouble in tuning outthis station and bringing in great dis-tances without the semblance of inter-ference.

A street car booster station is only 200feet distant and two heavy duty lines are40 feet away. This causes interference,but the "Victoreen" overcomes all this.

My set logs so perfectly that I use achart of kilocycles only. Opposite eachten kilocycles I have marked the dial set-tings.

FRANK E. GOODWIN,Editor, Messenger Newspaper League,

Kirkwood, Mo.

8 N A 1) I NV R I D April 17, 1926

The Action of TransBy Lewis Winner

Associate, Institute of Radio EngineersONE of the most interesting subjects

in the study of alternating currentand its branches is that of transformers.It should be remembered that the trans-formers employed in the radio and audiofrequency circuits are styled upon thesame fundamental principles as the powertransformers that will be discussed. Atransformer is a device made up usuallyof two windings, wound upon a core, ex-cept for radio frequency, when a core isnot used.

Suppose we place a conductor in amagnetic field and move it about. Wefind that an electromotive force is induced.This can be told by the use of a smallgalvanometer in series with the con-ductor, where a deflection of .the needlewill be noted. Now, if we rotate a simplecoil in a field which has no variations, insuch a way that lines of force surround-ing the coil have a tendency to increaseor decrease, an electromotive force is alsoinduced. This varies according to the rateof change of the total amount of magneticlines. By some very simple experimentsthe induction of the currents, by the aidof magnetic fields going in and out of acoil, can be determined. Connect a coilin shunt to an instrument that measuresvery small quantities, such as a gal-vanometer. Place a permanent magnetbar through the windings of the coil.The needle in the galvanometer will de-flect.

Deflection and OtherwiseAs long as the bar is kept still in the

coil there will be no deflection noted.However, as soon as the bar is taken out,the needle in the meter will deflect in theopposite direction. This of course showsthat when the flux cuts through a coil,a current is induced also. As the currentchanges from one direction to the other,so does the flux reverse its action. How-ever in this case, the bar has to be re-moved and then put back again, in orderto get a reversal of voltage. So let usplace this same winding in series with akey and a battery of cells, in magneticrelation to a winding having a greaternumber of turns than on the coil with thebar through its center. In shunt with thelarger coil, not the one with the barthrough it, place a sensitive meter. Now,as soon as you press the key you willnote a slight deflection of the meter.This is caused by he lines of force ex-panding from the coil with the magnetand weaving through the winding withthe larger amount of turns. Leaving thekey closed gives no deflection of the

meter, but as soon as the key is opened,the needle deflects in the oposite direction.This is the same as that which took placein the first experiment. Now, if the sourceof current is such that it alternates backand forth in the same manner as the openand closing action of the key, the linesof force about the larger winding willrise and fall. The current then movesabout in this winding. With a smallerwinding in the input and a greater wind-ing in the output, a consequent step up ofthe impressed voltage will be obtained.The voltage cannot be stepped up ordown unless the input winding is cut bycurrent that is alternating, pulsating or ofa direct interrupted character. Everypower transformer consists of a primarywinding, secondary winding, and a core oflaminations of iron, etc. The ratio of thecurrent in the secondary winding to thatin the primary winding is equal to theratio between the number of turns in thesecondary and the number in the primary.There are three types of transformerscommonly used in power work: (1), opencore; (2), closed core, and (3), auto -transformer.

What They AreThe open core transformer type has to

do with constant current transformers.These are used for lighting of the streetlamps, etc. The core consists of a bundleof soft Swedish iron. This is coveredwith several layers of insulating material.Over this the primary winding is placed.This consists of several layers of heavywire, usually the No. 14 bare copper type.Over this winding a tubing is placed.Then the secondary is wound, consistingof six or seven layers, wound in pan-cake style. Each layer consists of sev-eral thousands of turns of wire. Most ofthese are made with movable secondarycoils, so that a constant current at variousvoltages can be supplied to the line. Thecore is so made; as previously described,as to keep the secondary away from theprimary. A counterweight is attached tothe secondary windings. This is so madethat a balance is at hand, when the cur-rent is at the correct value. If the ratioof the impressed emf to the current,which is made in the secondary winding,should slip, the current would rise forthat time above the value at which it issupposed to be. The secondary coil willthen move away from the primary. Thisis caused by the action of the pulley.This lowers the emf force induced in thesecondary coil. The current then falls toits normal value.

The constant voltage transformer will benow discussed. Here the alternating cur-rent is impressed upon the primary wind-ing. This magnetizes the core at cer-

Wrapper of the PanelMakes a Good Template

1111111111114624n11111IN.464

MARKING THE cover of the panel.

Most panels, when purchased, arc en-closed in a heavy manila cover. Thesecovers can be used as templates. The

material to be placed on the panel is puton the cover, as if it were the panel. Allthe marking are then made. The panel isthen mounted and points registered onthe panel, through the paper, using ascriber. In this way danger of defacingthe panel by erroneous markings isavoided. Also, the covering provides arougher surface than the panel itself.This prevents slipping of .the pencil,enabling more exact markings. A punchor the needle point of a pair of dividersalso may be used for transcribing themarkings from the cover to the panel.

ormerstain periods. A flux, which is varyingaccording to the alternations of currentimpressed, then flows through the core.By mutual induction an electromotiveforce is induced into the secondary wind-ing. The current flowing in the secondarycircuit, is opposite to that flawing in theprimary circuit. As this current increases,a magnetic field is set up which acts intotal opposition to that present in thecore. The self-induction of the primarywinding is also reduced by this action.This permits more current to flow in theprimary winding. In this way, a rise inthe secondary current causes a rise in theprimary current, thereby balancing theinput current with. that of the output.

"The term ideal transformer," says EricHausmann, E.E., Sc.D., in his book onDynamo Electric Machinery, "may be ap-plied to one possessing neither hysteresisand eddy current losses in the core, norohmic resistance in the windings andhaving all the flux set up by the primarylink with the secondary also."

Resistance, Reactance, ImpedanceThe flow of a direct current through a

stated circuit is only opposed by plainohmic resistance. However, when deal-ing with alternating current, an entirelydifferent proposition is met. The flowis held back by the counter -electromotiveforce of the self-induction of the wire,as well as by plain resistance. This extraresistance of self-induction is commonlyknown as reactance. However, the com-bined opposition of the resistance andthe reactance of this circuit is commonlyknown as impedance. The .flow of cur-rent is governed by the impedance, as

the ohmic resistance. When in-ductance is present, in the circuit, the re-active pressure predominating, inductivereactance is present.

The impedance of the usual windings isvery high. This is due to the high in-ductive reactance and small resistance.

Ready for Polar Talk

E. A. BROWN, Chief Operator atstation 2CV, Richmond Hill, N. Y., atthe apparatus, with which he will pickup and relay messages received fromthe Navy Arctic Expedition, beingheaded by Lieut. Commander Byrd.The transmitter will also send mes-saf!es to the fliers in the far North.

(International Newsreel).

4

April 17, Yet, RADIO WORLD 9

A Neutralized TRF SetBy Ben A,plin

TO neutralize a stage of tuned radiofrequency amplification, grid -to -grid

method, is difficult for some home con-structors. The methodshown in Fig. 1 doesthe trick more hand-ily. The first thingthat is done is toplace a .neutralizingcondenser betweenthe grid post of theRF tube and the endof the plate orprimary winding(L3) of the tuner.This primary wind-ing is tapped at themidpoint, whichlead goes to the B

plus 135 -volt terminal.A tapped primary LI is for the antenna

system as a means of increasing or de-creasing the selectivity of the set as wellas affecting the degree of wave lengthresponse for volume reasons. A 3 -circuittuner is employed in the detector circuit.No rheostats are employed to regulate thefilaments of the tubes. This is taken careof by the automatic ballast resistors.Auto -transformers are employed in theaudio -frequency amplifying portion of thecircuit. These assure fine quality ofamplification. With the first tube act-ing as a radio -frequency amplifier only,the second tube as a regenerative detectorand the three tubes in the stages of AF agood rceiver is the result. It is patternedafter "Radio Broadcast's" Aristocrat.

The coils are a radio frequency trans-former, with tapped primary (L1L2) and a3 -circuit tuner (L3L4L5) with tappedprimary.

They are for tuning with two .0005 mfd.condensers, and the Sickles pair of Aristo-crat coils are shown.

Wiring DataOnly the wiring of the detector and the

RF tubes will be discussed, as the wiringof the AF stages is standard.

The beginning of the primary, LI, goesto the antenna post. The end of thiswinding goes to the ground post and tothe arm switch. The tapped windings go

BEN APLIN

=o C,

Lt e0

Ar

PA

FIG. 1, showing the wiring of the receiver.

FIG. 2, showing the back view of the receiver.

to the various taps on the switch. ,Eithera switch arm as shown in the photo-graphs, with the taps enclosed, or a switchwith the taps on the outside of the panelmay be employed. The beginning of thesecondary winding, 12, goes to thevariable plates of the condenser, Cl; andto a C minus post. The end of this wind-ing gdes to the stationary plates of thesame condenser to the G post on the firstsocket and to the stationary plates of amidget neutralizing condenser. The var-iable plates of the condenser N go to theend of the primary winding, U, 3. Thebeginning of this winding (5) goes to theP post on the first socket. The tapped

FIG. 3, looking down on the set.

portion of this winding goes to the B plus135 volt post on the strip. It also may goto a terminal of a fixed condenser, C5,while the other terminal of the con-denser may go to the A minus B minuspost on the strip. The beginning of thesecondary winding, L4, 6, goes to thevariable plates of the condenser, C2, andto the F plus post on the second socket.Point 7 goes to leak and condenser.

LIST OF PARTSOne TRFT with a tapped primary,

L1L2.One 3 -circuit tuner, L3L4LS.Two .0005 mfd. variable condensers,

C1C2.Three Thordarson Autoformers, AF1,

AF2, AF3.Two % ampere ballast resistors, R.Two % ampere ballast resistors, RI (for

power tube in last stage).One midget variable condenser, N.Three .25 mfd. fixed condensers, C4.One .001 mfd. fixed condenser, Cs.One .0005 mfd. fixed condenser (across

P and B of AFI), optional.One .5 megohm grid leak.One .1 megohm fixed resistor.One Centralab 500,000 ohm variable re-

sistor, P.One .00025 mfd. fixed grid condenser,

C3.One 2 megohm grid leak.Five sockets.One tickler knob.Two dials.One tap switch.One filament switch.One 7x24" panel.One 6 x 23" baseboard.One terminal strip.One single circuit jack.Accessories: A, B and C batteries, four

01A type tubes, one 112 tube, screws,nuts, connecting wire, etc.

FIG. 4, showing the panel view. (Photo by Hayden).

r4"

In PATITC1 NAMR11-1 April 17, 1926

Wiring the Portable Set

FIG. 5.The rear view of the portable receiver.

[The following is the third article onthe construction of the Bernard portable,an 8 -tube Super -Heterodyne. Part I waspublished is the April 3 issue. Part II a;-peared April 10. Nest week details ontrouble shooting and operation will be dis-cussed.]

By Herman BernardAssociate, Institute of Radio Engineers

N the construction of the Bernard Port -I able, or any other set encompassed insmall space, the panel layout determinesto some extent the layout of other parts,and if not taken care of properly will leadto considerable trouble. The followingpanel directions, and none other, must befollowed.

The rheostat is on a midline, 9' fromeither side of the 18' panel. The centralshaft of the rheostat is exactly 2" up fromthe bottom. The condenser shafts are4i4' from left and right respectively. Ifconstructional details are followed exactlyall the way through, unless a suggestionis accepted which will be presented later,these three parts are all that appear inany form on the panel. The holes formounting the panel to the baseboard maywell be four, 3' apart.

Baseboard LayoutIn laying out the baseboard these special

precautions are vital: The three Melo-formers (audio frequency transformers)must have the circumference of theirbases no less and no more than Y4' fromthe back of a 7)5" wide baseboard. Thefirst two medium frequency transformers(MFI, MF2) must be mounted so thattheir bases are just flush with the rear of

0 BOO

the baseboard. This means the line farth-est from the panel.

The necessity for these precautions onthe baseboard is that the General Radiocondensers are provided with counter-weights, and if the proper space is notallowed the counterweights would hit twotubes, if the -0IA type is used. in anycase, the receiver must be sufficientlyflexible to allow room for the larger tubes.Remember the point stressed in a previousinstalment, that if the interchangeableoption is desired a rheostat must be usedthat will pass 2 amperes, at least, andnot heat up. The Centralab will justabout do that, without serious overheat-ing, but if a power tube with double theusual 25 ampere drain is used in the laststage, when the set is modified for homeuse. the 2% ampere drain would be tooheavy for that rheostat, and the GeneralRadio type should then be used instead.

The FrontWe will now change our position,

figuratively speaking, and assume we arelaying out the baseboard. with the panelpart farther away from us, and the backof the baseboard nearer us, so that whenwe say "front" we mean the plane nearerus, and when we say "back" we mean theplane at the subsequent joint of the panelto the baseboard.

The panel mounting to the baseboardshould be deferred until later, to allowfree and easy movement in establishingthe baseboard parts in their proper posi-tions. and for most of the wiring.

First mount the audio transformers. AsMeloformers are used, because of theirsmall size and the efficiency of their flux,due to a new solid core, we find we havethree mounting holes on each of the bases.

O

-0 A. s-

e.ry / sassoami 11r, al SAO

ILIAAAD PUSTULE

DETAIL OF WIRING of the filament circuit of the BernardPortable. The arrangement is very simple indeed. A minus isconnected to one aide of the rheostat, the other side of whichgoes to F minus on all eight sockets. The A plus lead goesdirect from battery to the F plus posts of the eight sockets. Inmaking grid return leads to negative, be sure to distinguishbetween negative filament and negative A battery, as theserepresent different sides of the rheostat, hence different DC

voltage and resultant bias on the grids.

lee .+1c ti i, ulerlp located. Mount thetransformers so that the B plus posts areat right front. This automatically locatesthe P posts at right rear, the G posts atleft rear and the F posts at left front.Remember that front really means theback of the baseboard!

Take the left-hand audio transformer(AF3). One mounting screw is towardthe front, the others on the side, at rear.This front screw is 1):.' to the right ofthe 17' wide baseboard, and its centerjust a trifle less than back. The otheraudio transformers, second (AF2) andfirst (AF1) stages, are placed on a linewith the first one, left to right, and with3/16' separation between the circumfer-ence of the bases.

Tips, Sockets, TransformersNext locate the speaker output, con-

sisting of phone tip jacks. Usually onlythe jacks are procurable, so cut a pieceof hard rubber, 2)5" wide by I' high, andmount on the baseboard with angle ironswith '5' arms. Two such brass or othermetal angles are necessary, and the phonetip jack strip is so mounted that the tipsare inserted from the front (really whatwill be the rear of the set). If pressedfor room you may bend the phosperbronze connecting lugs of the phone tipjacks so that they turn upward. Thiswill not be necessary, however, unlessdirections are ignored, or unusually largejacks employed. Those in the laboratorymodel were the Pacent product.

Next arrange the three audio sockets,(6), (7) and (8), each socket exactly inback of an audio transformer. The cir-cumference of the base of maytouch the circumference of the base ofthe audio transformer behind which thesocket is placed. The sockets are of theX type, the Klosner product being used.The arrow, representing the "pin" side ofthe tube, should point toward the front,i.e., toward you, if you are working assuggested. That puts plus to the left,minus to the right, at the rear side of thesocket, while grid is at right and plate atleft, at front.

The MF Channel

Now mount the first medium frequencytransformer (MFI) at right, with thesecondary (marked "Sec.") at left rear,and the base flush with the front of thebaseboard, but not overlapping it. On thisitem of overlapping, be sure to take thisprecaution all the way through, startingwith the phone tip jack strip, at left. Eventhe heads of the screws that bind the stripto the brass angles should not extend be-yond the baseboard front line, because somany cabinets are just 71/." deep thatany obstruction will cause the front panelto stick out from the intended notch orgroove of the cabinet. Most cabinets.however, are 8' deep, many are 8Y.', butwe are working on a 7),." basis, and alsowe may care to build a special cabinetwith portability stressed.

The next medium frequency transformer(MF2) is mounted so that the U-shapedextension of the one (MF2) just barelymisses touching the same correspondingextension of the other (MFI). As Gen-eral Radio Type VI medium frequencytransformers are used, the reference ap-plies only to them, and the U -pieces arcthe curvatures through which the mount-ing holes are driven. The two mediumfrequency transformers are mounted inline.

You now have ample room to place thefilter transformer, (MF3), which is alsoa medium frequency amplifier coupler,


Full Textual Directionsbut larger in physical size, and sharplytuned electrically. While the others(MF1. MF2) have iron core, this one(MF3) has an air core. There is muchdispute as to whether the filter should befirst or last in the chain, and the onlycomment needed here is that if the filteris placed first the directions herewithgiven should be modified accordingly.Any one may consult his own preferenceon the filter sequence. The U -piece ofthe filter (MF3) almost touches that ofthe neighboring 271 transformer (MF2).By the way, the filter's designation is type331.

The oscillator socket (2) is located withcenter 7g- from the left and 1%" fromthe back, with arrow pointing towardyou, thus giving the same relative locationof all the socket arrows.

This leaves four more sockets to mount,(1), (3), (4) and (5). The one at extremeright (1), has its central point 134" fromright, and is placed as close to the firstmedium frequency transformer as is prac-tical. This may be determined by puttinga large size tube in the socket, or may bedecided empirically by locating the center4" from the back of the baseboard, or3%." from the plane nearer you, which isexactly the same point. Skip the secondsocket (3) for the moment and mount thetwo others (4) and (5). These are alignedwith the first socket. The third sockethas its center 6" from right, while thefourth socket is 84" from right.

Now, mount the variable condensersand rheostat on the panel, if you have notdone so already, and provisionally holdthe panel in the position it will occupyagainst the baseboard. Put an -01A tube

the remaining unlocated socket (3),and so place the socket on the baseboardthat the condenser shaft may be turned,when the counterweight is attached, with-out striking the tube. If you are to usethe -99 type tubes, and have no largetube handy, mount the remaining socketout of alignment with the others by just4", the socket being that much neareryou, that is, the theoretical "front." Allsockets are in line except this one and theosoillator.

The Jones multi -plug is mounted be-tween the filter and the first audio trans-former, so that the eight holes face you,and this plane is just inside of the frontof the baseboard.

Only the loop jacks, also of the phonetip variety, and the oscillator coil need tobe mounted. The same sort of strip andangles are necessary for the loop jacks aswere used for the output. This is located1" from the back of the baseboard andwith right-hand side, or "outside," only34" in from the right-hand side of thebaseboard. The condenser -leak combin-ations will be mounted as part of the wir-ing job.

Looking Toward the Audio Channel

FIG. 6.Corner view of the set, showing the manner of connecting from batteries to set.The exposed leads go to the batteries. It is impossible wrongly to connect the

plug. Note the loop jacks in foreground.

The oscillator coil need not be mounteduntil some of the wiring has been done.

Wiring DataConnect together all the F minus posts

of the sockets. Then connect togetherall the F plus posts of all the sockets.Connect this lead also to the red prongof the plug. Do not connect the F minusand F plus leads together. Connect theP posts of the two medium frequencytransformers MF1, MF2 to the P posts ofthe sockets that are behind them. The Pposts are not marked, but the side they-are on is marked "Pri" on the transformer,so regard the post nearer you (right front)as the P post of the transformer. Con-nect the P posts of the audio frequencytransformers, so marked, to the appropri-ate socket P posts. In each case this willbe the socket slightly to the right of thetransformer, because the P post of thefinal socket (last audio, extreme left)goes to a phone tip jack, so your socketsare always "one ahead" of your trans-formers. Connect the P of the final socketto the tip jack at left, rear. Join togetherthe F posts of the three audio transform-ers and carry this lead to the green lugof the plug. Join together the B posts ofthe second and third audio transformers(those at left) and carry this lead to theremaining open phone tip jack for thespeaker output and to the pink post ofthe Jones Multi -Plug. Join the B posts ofthe remaining transformers, the twomedium frequency MF1, MF2, the filter,MF3, and the first audio, AF1, and carrythis lead to the blue lug of the plug. TheB posts of the medium frequency andfilter transformers are at right, rear, whilethe B post of the first audio transformeris marked.

Join the grid -leak -condenser combina-tion C3R2. a single Micamold unit, so thatone side goes to the G post of the firstsocket, extreme right, and the other sidegoes to the rear loop jack, to which laterwill be connected to the stator plates ofthe variable condenser Cl.

The G posts of the next two sockets inline, tubes (3) and (4), right to left, go tothe plainly marked G posts of the mediumfrequency transformers nearest them,while the G post of the filter connects to

one side of the second grid -leak -condensercombination, C4R3, the other side of whichcombination goes to the grid post of thenearest socket (5), fourth socket fromright in the same line. The unconnectedside of the secondary of the filter goesto A plus.

Working from right to left, the G Postsof the second and third audio sockets goto the G posts of the audio transformersthat are in front of them. G of AF1 goesto G of socket (6), third from left. Theopen ends of the secondaries of themedium frequency transformers and, MF1,MF2, go to a lead which is joined to greenlug of the plug was previously connectedalso to the common lead of the F posts ofthe three audio transformers. The A pluslead to all sockets (F+) went to the redlug of the plug.

Now place the panel against the base-board in trial position again and locatethe oscillator coil between Cl, the right-hand variable condenser, and the oscillatorsocket. A 1.14" wood screw, with a bush-ing between the baseboard at the coil it-self, is driven into the baseboard to keepthe coil in place. The hole for this waslocated in a previous instalment.

Connect the nearer loop tip to the be-ginning of the primary Ll, of the oscil-lator coil, which is the terminal at the in-side, close to the celluloid collar. Theend of this winding, A plus, joins to thenearest F plus socket post. The begin-ning of the secondary of the oscillatorcoil, 12, which is near the end of theprimary, goes to the grid post of the oscil-lator socket.

The other end of the secondary goesto A minus.

Now mount the panel to the baseboard.Connect one side of the rheostat to thelead going to the F minus posts of allthe sockets, and the other side of the rheo-stat to A minus, represented by the greenpost of the plug. Now connect the vari-able condensers. There are two statorpoints and one rotor point on these, soselect a stator post on Cl, at right, jointhis to the grid leak -condenser com-bination, Ft2C3, other than the socket side.This is the tip jack at right rear.

(Concluded next week)

1'1 \k-r,nt t-1 April 17, 1926

Etiquette o Listening

WERE THE broadcasting lady, speaking on art or recipes, present at thesame timeas was her voice in this kitchen would she become highly insulted? Is it politeto turn even one's side to a cone when some one is talking? Is it proper to cleandishes then? What are the etiquette rules? Placing the speaker on the bird

hanger in the next room might soften the "offense." (Hayden)[In the follou'ing article, which ends his series on "Radio Music in the Home," Dr.

Alfred N. Goldsmith, one of the world's most noted and learned radio authorities, franklydiscusses important subjects scarcely ever broached. The sociological side of radio isdissected with great expettness, and both host and guests are told how to behave at a radioconcert. The advice is certainly pertinent at this time, when the fact that no fee or admis-sion is charged causes many to be noisy and impolite during programs of the finest artistry.Only recently such brilliant singers as La feritza and La Muzio were on the air during thesame week, and in many points where the programs were being received, instead of thrilledattention there was distraction and conversation, due only to the unruliness of a minority.How better to appreciate the best broadcast programs, or how to avoid preventing suchenjoyment by others, well describes the burden of Dr. Goldsmith's courageous (Miele.]

By Dr. Alfred N. GoldsmithChief Broadcast Engineer, Radio Corporation of America

IN rounding out the series of articles on"Radio Music In The Home," it has

seemed desirable to pay an imaginary visitto the broadcast listener's home and to dis-cuss with him how he can best use his re-ceiver so as to get the highest tone quality.Acoustic synchronizing, or complete fidel-ity of sound reproduction, depends to alarge extent upon the receiving set, thetubes, the loudspeaker, and the transmit-ting station itself. These matters havebeen explained earlier in this series. Theproper installation and use of the receiv-ing set is also an essential factor in suc-cessful acoustic synchronizing and onewhich should not be neglected.

It is first necessary to consider carefullywhere to place a radio receiving set andits loudspeaker. This is not a matter ofindifference-quite the contrary. The re-ceiving set, particularly if provided with aloop instead of an outside antenna, shouldbe located so that the loudest signals arereceived and with the least amount of in-terference from electrical circuits in thebuilding. It will certainly pay to spend aportion of an evening moving a loop re-ceiver around the living rooms to deter-mine the location where the bestsignals are produced. Generally thisis near a window and away fromthe main electric lighting circuits. Fur-thermore, the receiver should, if possible,be located where the dials are well illumi-nated so that stations can be readily lo-cated and fine tuning can be convenientlycarried out.

Speaker LocationThe loudspeaker need not be near the

receiving set and there are, in fact, someadvantages in having it at a distance from

the receiving set (for example, across theroom). If the receiving set is near theaudience and the loudspeaker is acrossthe room, the user of the set will perforcetune it in such a way as to give maximumsatisfaction to the audience. In otherwords, wherever possible, the receiving setshould be located where it gets the bestsignals and the audience should be groupedaround it if a louspeaker at a distance isused. If an outside aerial is used, theexact location of the receiving set is per-haps less important than in the case of aloop receiver.

It is desirable not to have the audiencenear an open window fronting on a noisystreet, because outside disturbances in-variably detract from the full enjoymentof reception. Fresh air in the room shouldbe admitted through a side window of themain street where less noise will come inas is always desirable.

Some rooms are far better than otherswhen it comes to obtaining excellentmusical reproduction. No general rule ispossible at present, but it may be saidthat open or shut doors, the presence orabsence of heavy hangings, the natureand solidity of the walls, the amount ofwall space taken up by windows, the areaof carpeted floor, and even the nature ofupholstery of the furniture and the num-ber of listeners in the room, all have aperceptible influence on the tone quality.

Consultation Valuable

It certainly pays to experiment by mov-ing the loudspeaker on a long flexible cordaround the room, placing it in variousparts of the room and on various levelsthough in general pointing at the audience.

A radio installation should not be hastilyand carelessly made-it should rather bethe result of numerous, careful experi-ments, and the combined opinion of anumber of listeners who will doubtless beglad to cooperate for an evening or twoin the interesting experiment of testing outtheir own sharpness of hearing and music-al taste.

Assuming that the receiver and loud-speaker have now been most advantage-ously located, it is still necessary to handlethe receiving set carefully to get acousticsynchronizing. To begin with, really selec-tive receivers frequently give tone qualitieswhich depend on the exact setting of thetuning dials. In such cases careful tuningis very important. Impatient manipulators,who carelessly spin the adjusting dials ofthe set and who simply will not take thenecessary trouble to tune carefully forbest quality, must be content with con-sistently inferior results. In radio, as inother fields, it is useless to expect fineeffects as a result of carelessness or in-difference. It is positively necessary tobe patient.

The discriminating user of a receivingset will tune slowly and thoughtfully, lis-tening, (perhaps with eyes shut), to thetone quality and to the relative suppres-sion of disturbances, such as static or in-terference. He or she will take every pos-sible care to get the best quality first, thenadjust the volume of the sound to the mostnatural value, carefully avoiding overload-ing and resulting rattles or tone distortion.

Must Be Local For QualityThe careful listener also will choose his

preferred station, which mustgenerally be local (except in the case ofsuper -power stations) so that he can besure of getting signals uninterrupted byobnoxious disturbances. The reception ofstrong signals is always preferable to thatof weak and disturbance -mangled signals.

After the set is tuned, it is desirable forthe manipulator of the set not to sit infront of the loudspeaker. While this maynot interfere with the sound reaching theaudience in many cases, it almost alwayshas a psychological disturbing effect. Itis better if there is no one near the loud-speaker. If the loudspeaker is a part ofthe receiving set, after the receiving sethas been thoroughly tuned, the user willbe well-advised to leave it alone and jointhe remainder of the audience. Continualfussing or tinkering with a receiving setduring a program is the most disturbinginfluence imaginable. When we considerhow irritating it would be if, during atheatrical performance, the stage elec-trician appeared in full view of the audi-ence at the side of the stage and continu-ally and ostentatiously adjusted the lightsin the auditorium, raising and loweringthem in an exasperating way throughoutthe thoroughly ruined performance, it willbe appreciated how desirable it is that theowner of the receiving set should carefullyadjust it and then go into the backgroundand stay there. Once the receiving set isreally tuned it is extremely desirable to"let well enough alone." The radioaudience should be permitted to listen tomusic and not be compelled to watch aradio juggler.

In this connection a simple piece ofradio stagecraft, and a desirable one, maybe mentioned. If possible the room inwhich one listens to radio programs should,during the performance, be dimly lit fromshaded lamps in soft colors. In the restfulatmosphere of a softly lit room one canmuch more easily appreciate a musicalmasterpiece. Glaring, vivid illumination

(Continued on page 26)

1


Radio UniversiFIG. 296, showing the panel layout desired by Mr. Marks.

AFREE Question and Ans-wer Department con-

ducted by RADIO WORLDfor its yearly subscribers only,by its staff of Experts. Ad-dress ..R ad io University,RADIO WORLD, 145 West45th St., N. Y. City.

PLEASE GIVE a panel layout for a5 -tube receiver, employing a stage oftuned RF amplification, a regenerativedetector, one stage of transformer coupledand two stages of autotransformercoupled AF amplification. A 3 -circuittuner is used in the detector stage. Vari-able condensers shunt the secondaries ofthe antenna coil and the tuner. A rheo-stat controls the filament of the RFtube. A rheostat also controls the fila-ment of the detector tube. The threeother tubes are controlled by ballast re-sistors. On the output of the detectorcircuit there' is a double circuit jack. Onthe output of the second stage of AFamplification there is another double cir-cuit jack. On the output of the last stageof AF amplification there is a single cir-cuit jack. A switch is inserted in serieswith the A plus lead. State the length ofthe panel and positions of the parts thatare to be placed on the panel.-JudsonMarks, Briley, Mont.

Fig 296, shows the suggested panel lay-out. Cl and C2 illustrate the first andsecond variable condensers, respectively.Let R1 be the arm of the rheostat con-trolling the filament of the RF tube. LetR2 be the arm of the rheostat controllingthe filament of the detector tube. Let J1be the jack in the detector output. LetJ2 be the jack in the second stage of AFamplification. Let J3 be the jack in thelast stage of AF amplification. A 7x24"panel is used. The shafts for the variablecondensers, Cl and C2, and also for thetickler, L4, are all 6" from each other andfrom the left and right hand sides, aswell as 3I/" from the top and bottom.The hole for the rheostat, R1, is 3" fromthe left and 3%" from the top and the bot-tom. The hole for the rheostat, R2 is 3"from the right and 3%" from the top andthe bottom. The hole for J1 is 3" from theleft and 1" from the bottom. The holefor the switch S2, is 9" from the left and1" from the bottom. The hole for the

Ant.

CI t

-r0 0-0 0 0

jack, J2 is 9" from the right and 1" fromthe bottom. The hole for the last jack,J3, is 3" from the right and 1" from thebottom.

* *I DESIRE to have a diagram of a

quality receiver employing five tubesThe first tube should be employed as anon -regenerative radio -frequency ampli-fier, the second as the regenerative de-tector, with a 3 -circuit tuner, followed bythree stages of impedence coupled audioamplification. A filament cpntrol jackshould be installed in the output of thedetector stage. A filament control jackshould be installed in the amplifier outputalso. State the data on the coils, con-densers, tubes, etc.-Wesley Branstone,Saco, Mont.

Fig. 297 shows the electrical diagramof the circuit which you desire. A regu-lation tunedl RFT and 3 -circuit tunerare employed. Tubings 354" in diameterand 4" high are employed for the primaryand secondary windings. The tickler iswound on a tubing 234" in diameter and2" high. LI, consists of the primary andsecondary winding in one. It has 55 turns.L2, the primary of the tuner, consists of8 turns. L3, the secondary, is wound onthe same tubing and consists of 45 turns.L4, the tickler, consists of 36 turns. No.22 double cotton covered wire is used towind the primary and secondary windings.The tickler is wound with No. 26 singlesilk covered wire. The secondary wind-ing portion of the antenna coil, Ll, andthe secondary winding, L3, are shuntedby .00005 mfd. variable condensers. Theantenna coil is tapped at the 6th turn.This turn is brought to one terminal ofthe fixed condenser, Cl, which has acapacity of .0005 mfd. The end of this6 -turn portion goes to the ground post.The G connection should, of course, goto the last terminal, adjacent to the an-tenna terminal. R1 and R2 are both 6ohm rheos ats, pass ng % ampere. R3,

Co

so-

which controls the filaments of the threeaudio tubes is also a 6 ohm rheostat, be-ing capable of passing 34 ampere. C4

is a .00025 mfd. fixed grid condenser. R5is a 2 or 3 megohni grid leak. L5, L6, 1,7and L8 are all 200 henry choke coils. R6and R7 are .5 megohm resistors. R4 is a500,000 ohm variable resistor. C5, C6, C7and CS are .25 mfd. fixed condensers.The -01A type tubes are employedthroughout. A 6 -volt storage battery isemployed used to light the filaments ofthe tubes. The plate' of the RF tube re-ceives 67% volts. The plate of the detectortube receives 45 volts. The plates of theamplifier tubes receive 90 to 135 volts. If90 volts are to be used, then a 4.5 volt Cbattery should be used. If 135 volts areto be used, then a 9 volt C battery shouldbe used.

* * *I HAVE a 1 -tube 3 -circuit tuner regen-

erative receiver, to which I have addedfour stages of AF amplification, e. g., onetransformer and three resistance stages.The volume js great, but the B batteriesdeteriorate very quickly. I use 135 voltson the plates of the three tubes in theresistance stales. Now, if I place a 9volt C battery in series with the gridresistance returns of these three tubes,will the batteries last longer?-GrantBleeker, Jersey City, N. J.

Use 9 volts on the final audio grid only.The other stages need no bias. GreatB battery economy will result.

* * *ARE .0005 mfd. variable condensers

employed in the Handsome Portable,which was described in the July 4 issueof RADIO WORLD by Herbert E. Hayden?-W. M. Wise, 24 28th St., Wheeling, W.Va.

Yes.* * *

IS IT necessary to use a separaterheostat when employing a -112 type tubein the last stage of transformer coupledAF amplification? If so, what typeshould be employed ?-W. Bemhard, Ber-gen Station, Jersey City, N. J.

A 6 -ohm rheostat, passing I/2 ampere, ora 112 Amperite should be employed.

* * *I HAVE a 4 -tube receiver, employing

one stage of tuned radio -frequency ampli-fication, a regenerative detector (usingthe 3 -circuit tuner), and two stages oftransformer coupled AF amplification.The filaments of the RF and the AF tubesare controlled by a 6 -ohm rheostat. Thedetector tube is controlled by a 20 -ohmrheostat. The -01A type tubes are em-ployed in the RF and detector stages, whilepower tubes are employed in the two AFstages. The volume and the DX are great,but I am troubled quite frequently withfrying noises. Is it possible that the trouble

0C

FIG. 297, showing the quality receiver, requested by Wesley Branstone.

12 I, .11/ 1 / 1111111 11'17,1 11

/ April 17, 1926

h

Eti uette of Listening

WERE THE broadcasting lady, speaking on art or recipes, present at the same timeas was her voice in this kitchen would she become highly insulted? Is it politeto turn even one's side to a cone when some one is talking? Is it proper to cleandishes then? What are the etiquette rules? Placing thei speaker on the bird

hanger in the next room might soften the "offense." (Hayden)

[In the following article, which ends his series on "Radio Music in the Home," Dr:Alfred N. Goldsmith, one of the world's most noted and learned radio authorities, franklydiscusses important subjects scarcely ever broached. The sociological side of radio isdissected with grcat expertness, and both host and guests are told how to behave at a radioconcert. The advice is certainly pertinent at this time, when the fact that no fee or admis-sion is charged causes many to be noisy and impolite during programs of the finest artistry.Only recently such brilliant singers as La Ieritsa and La Musks were on the air during thesame week, and in many points where the programs were being received, instead of thrilledattention there was distraction and conversation, due only to the unruliness of a minority.How better to appreciate the best broadcast programs, or how to avoid preventing suchenjoyment by others, well describes the burden of Dr. Goldsmith's courageous article.]

By Dr. Alfred N. GoldsmithChief Broadcast Engineer, Radio Corporation of America

IN rounding out the series of articles on"Radio Music In The Home," it has

seemed desirable to pay an imaginary visitto the broadcast listener's home and to dis-cuss with him how he can best use his re-ceiver so as to get the highest tone quality.Acoustic synchronizing, or complete fidel-ity of sound reproduction, depends to alarge extent upon the receiving set, thetubes, the loudspeaker, and the transmit-ting station itself. These matters havebeen explained earlier in this series. Theproper installation and use of the receiv-ing set is also an essential factor in suc-cessful acoustic synchronizing and onewhich should not be neglected.

It is first necessary to consider carefullywhere to place a radio receiving set andits loudspeaker. This is not a matter ofindifference-quite the contrary. The re-ceiving set, particularly if provided with aloop instead of an outside antenna, shouldbe located so that the loudest signals arereceived and with the least amount of in-terference from electrical circuits in thebuilding. It will certainly pay to spend aportion of an evening moving a loop re-ceiver around the living rooms to deter-mine the location where the bestsignals are produced. Generally thisis near a window and away fromthe main electric lighting circuits. Fur-thermore, the receiver should, if possible,be located where the dials are well illumi-nated so that stations can be readily lo-cated and fine tuning can be convenientlycarried out.

Speaker LocationThe loudspeaker need not be near the

receiving set and there are, in fact, someadvantages in having it at a distance from

the receiving set (for example, across theroom). If the receiving set is near theaudience and the loudspeaker is acrossthe room, the user of the set will perforcetune it in such a way as to give maximumsatisfaction to the audience. In otherwords, wherever possible, the receiving setshould be located where it gets the bestsignals and the audience should be groupedaround it if a louspeaker at a distance isused. If an outside aerial is used, theexact location of the receiving set is per-haps less important than in the case of aloop receiver.

It is desirable not to have the audiencenear an open window fronting on a noisystreet, because outside disturbances in-variably detract from the full enjoymentof reception. Fresh air in the room shouldbe admitted through a side window of themain street where less noise will come inas is always desirable.

Some rooms are far better than otherswhen it comes to obtaining excellentmusical reproduction. No general rule ispossible at present, but it may be saidthat open or shut doors, the presence orabsence of heavy hangings, the natureand solidity of the walls, the amount ofwall space taken up by windows, the areaof carpeted floor, and even the nature ofupholstery of the furniture and the num-ber of listeners in the room, all have aperceptible influence on the tone quality.

Consultation Valuable

It certainly pays to experiment by mov-ing the loudspeaker on a long flexible cordaround the room, placing it in variousparts of the room and on various levelsthough in general pointing at the audience.

A radio installation should not be hastilyand carelessly made-it should rather bethe result of numerous, careful experi-ments, and the combined opinion of anumber of listeners who will doubtless beglad to cooperate for an evening or twoin the interesting experiment of testing outtheir own sharpness of hearing and music-al taste.

Assuming that the receiver and loud-speaker have now been most advantage-ously located, it is still necessary to handlethe receiving set carefully to get acousticsynchronizing. To begin with, really selec-tive receivers frequently give tone qualitieswhich depend on the exact setting of thetuning dials. In such cases careful tuningis very important. Impatient manipulators,who carelessly spin the adjusting dials ofthe set and who simply will not take thenecessary trouble to tune carefully forbest quality, must be content with con-sistently inferior results. In radio, as inother fields, it is useless to expect fineeffects as a result of carelessness or in-difference. It is positively necessary tobe patient.

The discriminating user of a receivingset will tune slowly and thoughtfully, lis-tening, (perhaps with eyes shut), to thetone quality and to the relative suppres-sion of disturbances, such as static or in-terference. He or she will take every pos-sible care to get the best quality first, thenadjust the volume of the sound to the mostnatural value, carefully avoiding overload-ing and resulting rattles or tone distortion.

Must Be Local For QualityThe careful listener also will choose his

preferred station, which mustgenerally be local (except in the case ofsuper -power stations) so that he can besure of getting signals uninterrupted byobnoxious disturbances. The reception ofstrong signals is always preferable to thatof weak and disturbance -mangled signals.

After the set is tuned, it is desirable forthe manipulator of the set not to sit infront of the loudspeaker. While this maynot interfere with the sound reaching theaudience in many cases, it almost alwayshas a psychological disturbing effect. Itis better if there is no one near the loud-speaker. If the loudspeaker is a part ofthe receiving set, after the receiving sethas been thoroughly tuned, the user willbe well-advised to leave it alone and jointhe remainder of the audience. Continualfussing or tinkering with a receiving setduring a program is the most disturbinginfluence imaginable. When we considerhow irritating it would be if, during atheatrical performance, the stage elec-trician appeared in full view of the audi-ence at the side of the stage and continu-ally and ostentatiously adjusted the lightsin the auditorium, raising and loweringthem in an exasperating way throughoutthe thoroughly ruined performance, it willbe appreciated how desirable it is that theowner of the receiving set should carefullyadjust it and then go into the backgroundand stay there. Once the receiving set isreally tuned it is extremely desirable to"let well enough alone." The radioaudience should be permitted to listen tomusic and not be compelled to watch aradio juggler.

In this connection a simple piece ofradio stagecraft, and a desirable one, maybe mentioned. If possible the room inwhich one listens to radio programs should,during the performance, be dimly lit fromshaded lamps in soft colors. In the restfulatmosphere of a softly lit room one canmuch more easily appreciate a musicalmasterpiece. Glaring, vivid illumination



Radio UniversiFIG. 296, showing the panel layout desired by Mr. Marks.

A FREE Question and Ans-wer Department con-

ducted by RADIO WORLDfor its yearly subscribers only,by its staff of Experts. Ad-dress R ad io University,RADIO WORLD, 145 West45th St., N. Y. City.

PLEASE GIVE a panel layout for a5 -tube receiver, employing a stage oftuned RF amplification, a regenerativedetector, one stage of transformer coupledand two stages of autotransformercoupled AF amplification. A 3 -circuittuner is used in the detector stage. Vari-able condensers shunt the secondaries ofthe antenna coil and the tuner. A rheo-stat controls the filament of the RFtube. A rheostat also controls the fila-ment of the detector tube. The threeother tubes are controlled by ballast re-sistors. On the output of the detectorcircuit there' is a double circuit jack. Onthe output of the second stage of AFamplification there is another double cir-cuit jack. On the output of the last stageof AF amplification there is a single cir-cuit jack. A switch is inserted in serieswith the A plus lead. State the length ofthe panel and positions of the parts thatare to be placed on the panel.-JudsonMarks, Briley, Mont.

Fig 296, shows the suggested panel lay-out. Cl and C2 illustrate the first andsecond variable condensers, respectively.Let R1 be the arm of the rheostat con-trolling the filament of the RF tube. LetR2 be the arm of the rheostat controllingthe filament of the detector tube. Let J1be the jack in the detector output. LetJ2 be the jack in the second stage of AFamplification. Let J3 be the jack in thelast stage of AF amplification. A 7x24"panel is used. The shafts for the variablecondensers, Cl and C2, and also for thetickler, L4, are all 6" from each other andfrom the left and right hand sides, aswell as 31/a" from the top and bottom.The hole for the rheostat, R1, is 3" fromthe left and 314" from the top and the bot-tom. The hole for the rheostat, R2 is 3"from the right and 3%" from the top andthe bottom. The hole for J1 is 3" from theleft and 1" from the bottom. The holefor the switch S2, is 9" from the left and1" from the bottom. The hole for the

7C2

41IrGnd.

jack, J2 is 9" from the right and 1" fromthe bottom. The hole for the last jack,J3, is 3" from the right and 1" from thebottom.

* *. *I DESIRE to have a diagram of a

quality receiver employing five tubesThe first tube should be employed as anon -regenerative radio -frequency ampli-fier, the second as the regenerative de-tector, with a 3 -circuit tuner, followed bythree stages of impedence coupled audioamplification. A filament cpntrol jackshould be installed in the output of thedetector stage. A filament control jackshould be installed in the amplifier outputalso. State the data on the coils, con-densers, tubes, etc.-Wesley Branstone,Saco, Mont.

Fig. 297 shows the electrical diagramof the circuit which you desire. A regu-lation tunedi RFT and 3 -circuit tunerare employed. Tubings 3%" in diameterand 4" high are employed for the primaryand secondary windings. The tickler iswound on a tubing 23." in diameter and2" high. Ll, consists of the primary andsecondary winding in one. It has 55 turns.L2, the primary of the tuner, consists of8 turns. L3, the secondary, is wound onthe same tubing and consists of 45 turns.L4, the tickler, consists of 36 turns. No.22 double cotton covered wire is used towind the primary and secondary windings.The tickler is wound with No. 26 singlesilk covered wire. The secondary wind-ing portion of the antenna coil, Ll, andthe secondary winding, L3, are shuntedby .00005 mfd. variable condensers. Theantenna coil is tapped at the 6th turn.This turn is brought to one terminal ofthe fixed condenser, Cl, which has acapacity of .0005 mfd. The end of this6 -turn portion goes to the ground post.The G connection should, of course, goto the last terminal, adjacent to the an-tenna terminal. R1 and R2 are both 6ohm rheos ats, pass ng % ampere. R3,

Cs

which controls the filaments of the threeaudio tubes is also a 6 ohm rheostat, be-ing capable of passing 3/4 ampere. C4

is a .00025 mfd. fixed grid condenser. R5is a 2 or 3 megohm grid leak. L5, L6, 1.7and L8 are all 200 henry choke coils. R6and R7 are .5 megohm resistors. R4 is a500,000 ohm variable resistor. C5, C6, C7and C8 are 25 mfd. fixed condensers.The -01A type tubes are employedthroughout. A 6 -volt storage battery isemployed used to light the filaments ofthe tubes. The plate of the RF tube re-ceives 67% volts. The plate of the detectortube receives 45 volts. The plates of theamplifier tubes receive 90 to 135 volts. If90 volts are to be used, then a 4.5 volt Cbattery should be used. If 135 volts areto be used, then a 9 volt C battery shouldbe used.

* * *I HAVE a 1 -tube 3 -circuit tuner regen-

erative receiver, to which I have addedfour stages of AF amplification, e. g., onetransformer and three resistance stages.The volume is great, but the B batteriesdeteriorate ve -y quickly. I use 135 voltson the plates of the three tubes in theresistance stages. Now, if I Place a 9volt C battery in series with the gridresistance returns of these three tubes,will the batteries last longer?-GrantSleeker, Jersey City, N. J.

Use 9 volts on the final audio grid only.The other stages need no bias. GreatB battery economy will result.

* * *

ARE .0005 mfd. variable condensersemployed in the Handsome Portable,which was described in the July 4 issueof RADIO WoRLD by Herbert E. Hayden?-W. M. Wise, 24 28th St., Wheeling, W.Va.

Yes.* * *

IS IT necessary to use a separaterheostat when employing a -112 type tubein the last stage of transformer coupledAF amplification? If so, what typeshould be employed?-W. Bernhard, Ber-gen Station, Jersey City, N. J.

A 6 -ohm rheostat, passing 1/2 ampere, ora 112 Amperite should be employed.

* * *I HAVE a 4 -tube receiver, employing

one stage of tuned radio -frequency ampli-fication, a regenerative detector (usingthe 3 -circuit tuner), and two stages oftransformer coupled AF amplification.The filaments of the RF and the AF tubesare controlled by a 6 -ohm rheostat. Thedetector tube is controlled by a 20 -ohmrheostat. The -01A type tubes are em-ployed in the RF and detector stages, whilepower tubes are employed in the two AFstages. The volume and the DX are great,but I am troubled quite frequently withfrying noises. Is it possible that the trouble

IT

0 C

os.s.

B 2

A+ B-

5.0.

FIG. 297, showing the quality receiver, requested by Wesley Branstone.

14 RADIO WORLD April 17. 1926

FIG. 297, showing

may be in run down B batteries? Whatare other causes and remedies of thesenoises?-Thomas Trainson, 1301 DeKalbAve., Brooklyn, N. Y.

The trouble probably lies in your Bbatteries. However, you should be surethat all the prongs of the tubes are mak-ing perfect contact with the terminals ofthe sockets. Also be sure, that you havea noiseless grid leak. Be sure that thegrid of the tube is not sagging over sothat it makes and breaks contact withthe plate, whenever the set is jarred.Also shake the tubes and listen for looseelements. Loose contacts or broken con-nections in the tickler leads are also com-mon causes of frying noises. A bypasscondenser, 1.0 mfd., from A minus to Bplus amp. often helps get rid of noises.

* * *

IN REFERENCE to the VictoreenSuper -Heterodyne, described in the Feb.20, 27, March 6 and 13 issues of RADIOWont): (1) Can I use a 7x21" panel,instead of the 7x24" panel? (2) Will itbe 0. K. to place the antenna coupler ina separate cabinet so that it can be usedwhenever desired? I wish to place thisunit in a special battery compartmentwhich I have in my table. (3) Will theset work all right to use the loop de-scribed in the Oct. 31 issue of RADIOWORLD by Herbert E. Hayden ?-Fred W.Kernber, 220 Lincoln Ave., Endicott, N. Y.

(1, 2 and 3)-Yes.* * *

1 WOULD like to have a description ofthe wiring of the old type Harkness 2 -tube reflex. I would also like to have theconstants of the coils, condensers, AFT,rheostats, etc.-Roger Stryker, N. Y. C.

Two radio -frequency transformers areemployed. Let the primary of the firstRkT be known as LI and the secondary

the diagram, requested by J. L. Kramer.

of the same coil as L2. Let the primaryof the second RFT be known as L3, thesecondary as L4. The secondaries, 12 andLA, consist of 62 turns of No. 22 DCC wirewound on a form 21/2 in. high and 3 in. indiameter. Ll, the primary of the firstRFT, is wound over the secondary, L2,and consists of 10 turns. L.3, the primaryof the second RFT is wound over thesecondary, L4, and consists of 10 turnsalso. Empire cloth is used as an insulat-ing medium between the primary and thesecondary windings on both RFT. Vari-able condensers having a capacity of.00035 mid. maximum, are employed toshunt the secondaries 1.2 and IA. The firstRFT is mounted on the end plate of thevariable condenser shunting its secondaryand at right angles to the condensershunting the secondary of the secondRFT, which is also mounted on the endplate. The AFT employed for reflexingis of a high ratio type, e. g., 6 to 1. TheAFT used in the stage of standard AFamplification is of the low ratio, variety,e. g., 3 to 1. Tubes of the -01A typeshould be used. The wiring will now betaken up. Consider the variable condensershunting the secondary of the first RFTas Cl, the other condenser, as C2. Thebeginning of the primary winding LI goesto the antenna post. The end of this samewinding goes to the ground post. Thebeginning of the secondary winding 12,goes to the G post on the high ratio AFTand to the variable plates of the variablecondenser, Cl. The F post on this AFTgoes to the ground post. The end windingof the secondary 12 goes to the station-ary plates of Cl and to the G post on thefirst socket. The beginning of the pri-mary, L3, goes to the P post on this samesocket. The end of this winding goes to theP post on the low ratio AFT. The begin -

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Street

City and State

ning of the secondary winding, IA, goes tothe rotary plates of C2 and to the base ofthe crystal detector or low potential point.The end of the secondary winding goesto the stationary plates of C2 and to theB post on the high ratio AFT. The Ppost on this AFT goes to the catwhiskeror low potential point of the crystal de-tector. The B post on the low ratioAFT goes to the B plus 671/2 volts post.The G post on this AFT goes to the Gpost on the second socket and to oneterminal of a .001 mfd. fixed condenser.The F post on this AFT goes to the armof a rheostat, which also goes to the Aminus post. It also goes to the otherterminal of the fixed condenser. The re-sistance wire terminal of this rheostat,which is a 6 ohm, 'A ampere type, goes tothe F minus posts of both sockets. TheF plus posts of both sockets are con-nected together. They then go to theA plus and B minus posts. The F postof the high ratio AFT, besides going tothe ground, also goes to the A minuspost. The P post on the second socketgoes to the top terminal of a single cir-cuit jack. The bottom of this jack goesto the B plus 671/4 volt post.

I HAVE built Wright's Reflex, asdescribed by H. E. Wright, in the Janu-ary 31, 1925, issue of RADIO Woken. Thesignals of stations below 460 meters arevery loud. However, above that I can-not hear a station. What can I do toremedy this?-C. M. Parker, 100 KingSt., Burlington, Vt.

Add 8 turns to the secondaries, 12 andL4, and lengthen your antenna.

* *

I WOULD like to have the electricaldiagram of a 4 -tube receiver employinga crystal as the detector, a stage of tunedRF amplification, a stage of transformercoupled AF amplification and followed bytwo stages of autotransformer AFcoupling. The data on the coils and con-densers, etc., would be very much appre-ciated.-J. L. Kramer, 939 Longwood Ave.,Bronx, N. Y. City.

Fig. 297 shows the schematic diagramof a receiver based upon the requisitesyou state. The primaries LI and L3 con-sist of 10 turns. The secondaries, L2 andL4, consist of 45 turns. Tubings 3i/t" indiameter and 4" high are employed. No.22 double cotton covered wire is used.There is a h" spacing between the prim-ary and the secondary windings. CI andG2 are both .0005 mfd. variable condensers.C3 is a .001 mfd. fixed condenser. C4 isalso a .001 mfd. fixed condenser.' P is a400 ohm potentiometer. CD is a fixed oradjustable crystal detector. R1 is a 10ohm rheostat. passing 14 ampere. R2. R3and R4 are ally ampere ballast resistors.The variable resistor in shunt to the gridcircuit of the third tube is a 500,000 po-tentiometer. The fixed resistor in shunt

NeisApril 17, 1926 RADIO WORLD 15

to the grid of the last tube is of the .5megohm type. Fixed condensers of the1 mfd. type are used as stopping con-densers. The -01A type tubes are usedthroughout. You will note that althoughthere is a double circuit jack in the de-tector output, according to wiring dia-gram, the audio tubes will have to burnall the time if the reception from thedetector is to be obtained. However, byinstalling a switch in series with the fila-ments of the audio amplifier tubes onlyand another in series with the filamentof the RF tube, you may listen to theRF and the detector separately, the fila-ments of the AF tubes being turned off.

INFORMATION AS to the 1926 ModelDiamond would be greatly appreciated.(1) Will it be all right to use a 199 typetube as a radio -frequency amplifier. theproper filament resistances being used?(2) Would it be all right to purchase two3 -circuit tuners, use one as a regulation3 -circuit tuner, omit the._ ticker coil fromthe other and use it as on RFT? (3) Is it0. K. to use the Birnbach tuner? (4)About how far should the RFT and the3 -circuit tuner be from each other? (5)Will a 7x2I in. panel be large enough tohold the parts to constitute this receiver?(6) Can a baseboard be used instead of asub -panel? (7) Could two transformersbe used instead of the resistances in theAF stages? (8) It is all right to use a rheo-stat to control the filament of the detec-tor, a rheostat to control the filament ofthe RF tube and one rheostat to controlthe filament of the two AF tubes? (9)Could the double circuit- jack be placedafter the first stage of AF amplificationinstead of after the detector as is usuallydone? (10) Would the Freshman Varia-ble grid leak and condenser be satisfac-tory to use?-August Steve, 120 ClareSt., Buffalo, N. Y.

(1) Yes. (2) Yes. Use the "vacant"tickler in the aerial circuit. (3) Yes. (4)About 65 in. (outer circumferences). (5)Yes. (6) Yes. (7) Yes. See the Jan. 23issue of RADIO WORLD. (8) Yes. (9) Yes.(10) Yes.

*PLEASE publish types of coils, dis-

tinguishing binocular, solenoid and toroid.-Henry Johnson, Oil City, Pa.

Fig. 298, shows the four popular typesof coils. The coil at the left is knownas a figure eight or astatic type. Herethe fields of both the primary and second-ary windings oppose each. This preventsinter -stage coupling. It is also very eco-nomical as to space. The next one is thepopular solenoid coil, wherein a large dia-meter and spaced windings are used. Thenext coil is also a solenoid. Here how-ever, a smaller diameter is employed, withno spaced windings. The efficiency ofboth these coils is approximately the same.The last coil is a toroid.

FIG. 298, showing the four types ofcoils.

External Units RequireCare in Battery Leads

When connecting external units, suchas wavetraps and loop attachments em-ploying a tube, radio -frequency amplifiersand audio -frequency amplifiers to a singledetector unit, etc., it is always advisableto watch the A and B battery connec-tions. That is, if in the detector unitthe A plus is connected to the B minus,be sure that when you connect the ex-ternal unit, the A minus doesn't go tothe B minus, as this will cause a short.

A

IN A we have one method of increas-ing the wavelength of an antenna, bythe insertion of a fixed condenser inshunt to the antenna and the ground.This has the same effect in some in-stances as adding turns to the second-ary or increasing the physical lengthof the antenna. In B we have amethod of decreasing the wavelengthof the aerial by inserting a fixed con-denser in series with the ground lead.In both instances the condenser shouldbe of small capacity, say not more

than .00025 mfd.

Carnegie InstituteTo Give a Radio Course

As a result of the demand that has beendeveloping during the past few years, acourse in Radio Communication, it is an-nounced, is included in the plans for thesummer session this year at the CarnegieInstitute of Technology in Pittsburgh.According to the plans, the College of In-dustries will give a six weeks' course inRadio Communication from June 28 toAugust 6 under the direction of the De-partment of Electric Equipment and Con-struction.

Although the course is offered primarilyfor the benefit of teachers of industrialeducation, anyone, the announcementpoints out, is eligible to take the work.No special restrictions have been placedon a prospective student's educationaltraining in order to enroll.

New System of RadioUses 3 Frequencies

VIENNA.A marvelous system of transmission and

reception on three separate frequenciesthat change places 60,000 times a second,though used for simultaneous work, hasbeen invented by Emil Marek, it is an-nounced. Each frequency is used 20,000times a second. Utter privacy is assuredby this system, which is thus unlikebroadcasting, says the inventor.

Marek has had a varied career. He isaccused of cutting off his leg to collect$400,000 insurance.

Robbers Warn EngineerResistance is Perilous

CHICAGO.Robbers kidnapped J. Elliott Jenkins,

radio engineer and husband of AlexandraCarlisle, former actress. They wanted hisautomobile 'and drove him off in it.. Heasked them for carfare home, which theygave him, but kept the car.

A newspaper reporting the happening,said: "The robbers warned Jenkinsagainst resistance."

Lighter Element is FoundFor Storage Batteries

VIENNA,Lighter weight storage batteries are

made possible by an element discoveredby Gunther Polech, of the PolythechnicalSchool. It is one -fifth the weight of leadand is said to have greater capacity andpower. It is particularly suitable for radiouses, says the inventor.

HOOVER'S ENCOMIUMSecretary Hoover declares the regula-

tion of radio is the greatest example ofself-government in business.

RADIO TICKERS NEXTThere is talk of radio eventually re-

placing stock tickers.

The New Power Booster(Concluded from gage 5)

system, and the comparison of that in-vention with the rejector wave trap func-tion, I need say only this: The circuitL4C3, if working as a rejector, wouldabsorb from the antenna circuit and thesecondary L3 the energy radiated on thewavelength to which C3 is tuned. Thus,if WEAF interferes, setting C3 to WEAF'swave would leave the receiver proper freeto bring in other stations clear of inter-ference from WEAF. But when the ac-ceptor system is at work, C3 must betuned to WEAF's wave, or ever soslightly off that wave, for greatest re-sponse, indeed, if it is not, the stationmay not be heard. In other words, thepower booster is tuned like the othertuned circuits, those of the receiver properL3C1 and L6C2. I have been distinguish-ing between the power boster L4C3 andthe "receiver proper" only for the sakeof clarity. Such a distinction is quitecorrect, if L4C3 functions in rejector style,for then the circuit is tuned independentlyof the receiver, or, rather, at variancewith it. In the power booster plan, L4C3is really a part of the receiver itself, asit offers a path of low impedance to theradio current, which flows back to thegrid circuit in the familiar fashion of suchoscillating circuits. Hence, with morestages, the system still would be applic-

able, and with only one stage, as here, itis yet of fine service, due to the specialconstruction of L5, as already discussed.The power booster is known technically asa reflector circuit and little ever has beensaid of this phenomenon.

The Rest of ItThe rest of the circuit presents features

familiar to all who know radio, Afterthe detector tube come two stages ofaudio amplification, where transformersare the coupling media. The C batteryin the first RF stage is principally a Bbattery current saver, but may be omit-ted. The C battery in the audio stagesmust be included, if one has any interestin conserving B battery consumption andimproving quality.

The fast-growing popularity f thelight switch, which the a red lightglow on the panel when the set is on,impelled me to include this attractiveitem. The switch is primarily an off -and -on switch, and may be used ex-clusively for that, without the light. Byputting a flashlight bulb in the specialsocket with which each such switch isprovided, you have the light feature. Theflashlight bulb will not draw more than.25 ampere at 6 volts..

In the list of parts it is assumed 5 -volttubes are used. If otherwise, select theproper rheostats and ballast accordingly.

16 5? A T1 T rl Cs r Tl April192617, '^1

Signals 600 Miles AwayBetter Than at Half ThatRadio signals are better 600 miles from

a broadcast transmitter than they are 300miles away, according to engineers of theradio department of the General ElectricCompany. under whose supervision an ex-haustive investigation of radio wave pro-pagation is now being made.

For several weeks thousands of radiolisteners have been cooperating with theGeneral Electric Company by reporting onreception of signals on broadcast bands.These cooperative tests are still under wayand the conclusions are only such as sug-gest themselves from the preliminary re-ports. The engineers do not claim thatthe conclusions are absolute and cautionthat more exhaustive investigation may re-veal some facts not yet apparent.

The Average ResultIn observing the variation of signal

strength, it was found that the strengthof the signal drops off rapidly during thefirst 300 miles from the station and that,contrary to what might be expected, thesignal strength actually increases and isapparently a little stronger at 600 milesthan at 300 miles. Beyond the 600 milepoint, the strength decreases again slowlyto the limit of the range of the station.These distances are not definite values ;they are averages from a large number ofreception reports.

A study of the zones in which fadingoccurs shows that it is worst at about200 to 500 miles from the station and thiszone, from 200 to 500 miles, is the terri-tory in which there is the greatest per-centage of rapid -fading reports. Broad-cast service is better at 600 miles than 300from a station because fading is .less andthe signal strength is slightly greater.These distances vary slightly with thepower of the transmitter. Rapid fadingis _not often observed, however, and inthis respect the regular broadcast waves

seem to be different from the short waves.The reports indicate that the rate of fad-ing increases steadily as the wave lengthgrows shorter.

Effect of the WeatherThe main objective of the investigation

in cooperation with widely scattered,volunteer assistance, is an answer to thequestion: What is the relation betweenweather and radio reception, or do wea-ther conditions influence radio? Variationsof signal strength, static and fading are allbugaboos of the listeners and an effortis being made to relate these irregu-larities to changes in barometric pressureand temperature, If definite relationshipsbetween radio reception and weather con-ditions can be established, it will be pos-sible to predict receiving conditions inany, part of the country as reliably as it isnow possible to forecast weather condi-tions.

Thus far investigations by General Elec-tric engineers indicate that the connectionbetween barometric pressure and tem-perature with radio conditions is not defi-nite, or if it is definite, that it is so com-plex that it is not yet understood.

Temperature of Little EffectTemperature seems to have no effect

on the signals themselves, although it isknown that in Summer there is an in-crease in static. The study so far showsthat the barometer makes little differencewhen both transmitter and receiver areat the same pressure. When transmissionis from a high to transmis-sion is best at short and at long distances,but at medium distances of about 60 milesit is best from an area of low pressureto an area of high pressure. The phe-nomena is apparently related to the dis-tribution of storm areas over the countryand requires a great deal more study.

Another Station SquatsOn Barred Wavelength

WASHINGTONFire has broken out in a new place

among broadcasters who are dissatisfiedwith the wavelength assigned them by theDepartment of Commerce and who havetaken the law into their own hands andselected an air channel more to their lik-ing.

According to reports to the Departmentof Commerce, Station KWKH, owned bythe W. K. Henderson Iron Works andSupply Company, at Shreveport, La., hasfollowed the example of WJAZ, ownedby E. F. MacDonald, Jr., and is operatingon 329.5 meters, which is assigned exclu-sively to Canadian stations.

At the present time there is pendingin the Chicago courts a suit against Mr.MacDonald for violation of the law inoperating on 329.5 meters without author-ity. The case hinges on the right of theDepartment of Commerce to assign wave-lengths to stations. A court decision isexpected soon.

Before it decided to take matters intoits own hands, KWKH operated on 261meters, as did 14 other stations. Dissatis-fied, KWKH applied to the Departmentof Commerce for permission to increase

its power. The request was denied bythe Department of Commerce on theground that with higher power KWKHwould drown out the other stations on 261meters. The inevitable result, according toDepartment of Commerce officials, wouldhave been that the other stations alsowould have likewise increased their powerin an effort to drown out KWKH.

No action will be taken on the Shreve-port case by the Department until a de-cision is made on the Chicago case."If all the bad actors would go aheadand operate on 329.5 meters," said ChiefRadio Supervisor Terrell. "it would solvea big problem for us. We could ask theCanadian Government to release thatwavelength and give them another in ex-change for it."

BASEBALL MOST POPULARIn the remarkable development of day-light broadcasting during the past year,baseball has proved the most popular fea-ture. Probably more than anything else,it was baseball along with football, thatbrought broadcasting stations to realizewhat a good bet was being overlooked

if they closed down during daylight hours.

Japan's Announcerette

HEREMidorikawa, the first and only womanannouncer in Japan, standing beforethe microphone in the studio ofstation JOAK, Tokio. As may beseen, JOAK seriously avoided picking

a flapper. (Kadel & Herbert).

SHE IS-Madame Akiko

Analyzes Human Nature

Cynthia GREY, newspaper columnistof the "Denver Express," before themicrophone of KOA, conducting anew matinee attraction for women,known as "microphone snap -shots ofhuman nature." (Richard Beghtol).

A SPEAKER, placed as above, istoo close to the listener, when he

leaves the table. (Hayden).


Programs Delight Baby

ANYBODY who thinks that a radioreceiver is something to delight onlythe adult and the adolescent is muchmistaken, as these photographs ofNorma Hayden, taken by her father,Herbert E. Hayden, prove. The raptattention of a doubting listener, goo -goo glee over some funny animalisticnoise by an imitator, and profoundserenity at the strains of a sentimentalwaltz are emphatically registered in

the photographs.

Headsets for Patients

THE SOJOURNERS, a Masonic or-ganization of Army, Navy and Marineofficers, are to supply headsets forstricken service men. Photo showsCapt. N. Blackwood at Naval Hos-pital, Brooklyn, N. Y.; W. E. Hark-ness and Major E. Bowes. (Foto

Topics).

Sets at Efficiency Peak,Dr. Dellinger AnnouncesBy Thomas Stevenson

WASHINGTON.Too much credit cannot be given radio

engineers for achievements in broadcasttransmission, reception and apparatus, ac-cording to Dr. J. H. Dellinger, Chief ofthe Radio Laboratory of the Bureau ofStandards.

Dr. Dellinger believes that the newestand most recently designed sets on themarket cannot be improved to any con-siderable extent so far as service is con-cerned. He thinks future improvementsin broadcasting will be in the transmittingrather than receiving end. He believesthe radio engineers will eventually over-come most of the outstanding problemsand that broadcasting service may be-come as reliable as the telephone.

The Miraculous Feature"In the past three or four years there

has been widespread popular mystificationover how radio is done,' says Dr. Dellin-ger. "People have been inclined to classifyit along with the acts of the conjurer orin some cases to link it closely with thedeeds of the Almighty.

"The miracles of radio, actually and inthe truest sense, are produced not frombatteries, coils and electrons, but fromthe brain of the radio engineer, and whenthe processes of radio are analyzed theyare no more mysterious than any otherfamiliar process.

"This is the day of the radio engineer,in still another sense. Progress in radiohas been up to the present by empiricism.Its foundations have now been laid. Theoutlines of its major forms of service tohumanity now appear and the task ofperfecting this service and its instru-mentalities is the task of the radio en-gineer. He must and he can apply theprinciples of science and technology toadvance beyond the empirical foundationsof the subject and obtain from it, by bothlogical and laborious procedure, all of itspossibilities.

Task an Important One"Those who work in radio belong to a

recognized branch of engineering whichhas a unique responsibility. It has beensaid that the progress of civilization con-sists in learning how to better employand transform energy. Such words asthose state the mission of all engineers,but the material with which he workstakes the radio engineer beyond even this

control of physical energy, for the usesof radio today have vitally to do with theuse and control also of human energy.

"A well-known radio engineer in oneof his moments of tribulation said thatthess days a radio engineer must be allof the following things: an electrician, aphysicist, an expert in acoustics, amechanical engineer, a musician and adiplomat. It is a fact that radio has be-come a large subject. A few years ago,within our own lifetimes, it was an aptsaying that no one person could knowall the sciences. The multiplication andramification of knowledge has now be-come so great that as any of us in ourmore ingenuous moments vvill admit, noone person can even know all of radio.I suppose that we can say that this branchof enghttering has arrived, when it hasbecome so specialized that a person work-ing in one branch of it can give an intel-ligent disquisition that his fellow membersin the profession are not able to under-stand.

Progress Is Excellent"Radio engineers can take great satis-

faction not only in the particular field thatlies before them but also in the substan-tial manner in which progress is goingforward. We have perhaps gone beyondthe point where the daily newspapers turnto radio for the creation of a daily sen-sation, but to the engineer who reallyknows what is being done there are manysubstantial advances and improvements inactive progress at the present time. Theuniform forward movement along thewhole front of radio problems and activi-ties is a genuine cause for optimism, andoptimism is conspicuously the attitude ofall workers in radio whether in its en-gineering, scientific, commercial or socialaspects. I would not be misunderstoodas intimating that its problems are solved-by no means. The existence of a num-ber of healthy man-sized problems is whatgives zest to the game.

"The chief concerns of radio engineer-ing just now are: perfection of broad-casting and the penetrating of the mys-teries of radio wave propagation. Thesecan be considered as, in a sense, a singleproblem since the first cannot go veryfar forward without the second, yet thesetwo comprehend broadly the two majorstreams of engineering thought and effortat present. There have been great prog-ress and fine achievement in both of themduring the past year."

(Copyright. 1926, by Stevenson Radio Syndicate)

South Is Enthusiastic;New Orleans Static Bound

WASHINGTONReturning from a trip to Atlanta, Nash-

ville, New Orleans, Jacksonville, Tampa,and Miami, W. E. Downey, TechnicalRadio Expert of the Department of Com-merce, reports enthusiasm for radio at allpoints excepting Key West.

"The stations I visited are doing goodwork," Mr. Downey said, "and programsare very much appreciated by the peoplein those vicinities."

Mr. Downey also reported that staticconditions were giving some trouble. He

found it worst in New Orleans, where itwas frequently impossible for them to getanything outside of Texas and a few Chi-cago stations. KDKA, he added, was themost constantly heard. Mr. Downey saidthat New Orleans seemed to be in a sortof static pocket at the present time.

His trip was part of a program mappedout by the Department of Commerce tosee what the needs of certain radio dis-tricts might be, on the chance the De-partment of Commerce secures the addedappropriations, in a Senate bill.

tJ AnIc- UM T April 1 /17, 1 7,A.,iniA

Sets Using 1, 2, 5 or 6 Tubes

THE ELECTRICAL diagram of the 2-C, 5 -tube receiver, described in the January 2 issue of RADIO WORLD by Capt. P. V.O'Rourke. LI and L3, the primaries shown by the heavy white lines, are wound in the middle of the secondary and side byside with the continuation of the secondary winding. The secondary, using .00035 mfd. variable condensers, consists of 65

turns on 3" diameter.

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410

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Li

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A

THE SCHEMATIC electrical diagram of a 6 -tube quality receiver, employing two stages of tuned radio -frequency amplifica-tion, a non -regenerative detector and three stages of resistance coupled audio -frequency amplification, described in theDecember 19 issue of RADIO WORLD. RI is a 1¢ ampere ballast resistor controlling the filaments of the first RF and thedetector tubes. The filament of the second RF tube is controlled by a 14 ampere ballast resistor. A 34 ampere ballast re-

sistor controls the filaments of the three audio tubes.

2

B+Det.

B+Amp.

A+

A -

THE ELECTRICAL diagram of a 2 -tube, 1 -control receiver. A stage of tunedradio -frequency amplification and a non -regenerative detector are employed. Adouble condenser, C, with each section having a capacity of .0005 mfd., is employedto tune the secondaries of the two RFT. Standard radio -frequency transformers,with secondaries wound so that they will cover the entire wavelength from 200 to550 meters, when shunted by .0005 mfd. variable condensers, should be employed.Two 20 -ohm rheostats are used to control the filaments of the tubes. A .00025 mfd.grid condenser, C3, and a standard 2 megohm grid leak, R3, are used. Note that the

grid leak is in shunt to the grid return instead of in shunt to the condenser.

THE CIRCUIT diagram of the popu-lar 1 -tube regenerative 3 -circuit tunerreceiver. This receiver is adapted forreception on either the short or thelong waves. This is done with theaid of the switch, S. If the secondaryconsists of 45 turns and when shuntedby a .0005 mfd. variable condenser asabove, tunes from 200 to 550 meters, atap at the 20th turn will enable you toreceive signals from stations operatingfrom about 100 to 200 meters. The-01A type tube works very satis-factorily in this set, having a platevoltage of 45. A 6 -ohm, xq ampererheostat is placed in series with thenegative leg of the filament. A .001mfd. fixed condenser is placed in

shunt to the phones.


FACTORY SETSADEPARTMENT Conducted for Present and Prospective Owners

of Manufactured Receivers and Equipment. Address Questionsto Factory Set Editor, RADIO WORLD, 145 West 45th Street, New YorkCity.

RADIOLA NO. 25 is a second har-monic 6 -tube Super -Heterodyneequipped with the new UX 120 drybattery power amplifier tube. Thenew R. C. A. uni-controlled mechan-ism employed on all its new modelsallows sensitive tuning by means of a

single control.

WHEN the Radio Corporation ofAmerica announced its new line of

Radiolas, Radiotrons, Rectrons, Loud-speakers and Current Supply Devices; E.E. Bucher, General Sales Manager, saidthe new sets, tubes and loudspeakers werethe most complete with regard to technicalperformance of the individual items in theline, price range and quality, which theR. C. A. had thus far offered the public.

The Super -Heterodyne circuit, with re-finements, remains the standard of the R.C. A. receiving sets. The loudspeakers ofa new type, which the R. C. A. and its as-sociates have been developing in the lab-oratory, made their appearance as a com-mercial product for the first time, in threetypes.

When the Radio Corporation of Americaperfected the Super -Heterodyne circuit,sealed it into a catacomb and placed it onthe market early in 1924, part of the an-nouncement read:

"After years of experiment and observa-tion, and after a long look into the future,the keen eyes of radio experts and thealert minds of technical and sales engin-eers agree that, as far as they are nowable to determine, the Super -Heterodyneis and will remain the ultimate circuit forall radio broadcast listening."

Speaker Design"Equally impressive advances have been

made in the design of loudspeakers," saidMr. Bucher. "These speakers embodyentirely new principles. One is intendedfor direct operation of Radiolas, eliminat-ing dry batteries or storage batteries. An-other operates from an AC driven recti-fier -power -amplifier unit known as the'Uni-Rectron, and. the third, the mostpowerful of all, is of such design that weclaim for it the full volume of an orchestraor hand, in the home, without distortion.

"Keeping pace with the tremendousadvances in loudspeaker design was theproduction of three new Radiotrons. Thesenew tubes are all power amplifiers. TheUX120, for use in the last stage of audio-frequency amplification of a broadcast re-ceiver, is designed for the improvement ofvolume and quality of dry battery oper-ated receivers. The UX112, a storage bat-tery operated Radiotron, for increasingthe volume and quality of storage batteryoperated sets; and the UX210, giving loud-speaker volume and distortionless repro-

duction far in excess of that provided byany amplifying tube heretofore produced.

"We have spent many months in per-fecting current supply devices, and arenow convinced that the faults common tosuch devices have been overcome. Im-portant among the improvements are theability of the instrument to deliver suffi-cient output and to maintain the plate

_ voltage under load. The most difficult ob-stacle to overcome was the elimination ofthe hum from lighting circuits which, withmodified cone type loudspeakers is ampli-fied to a much greater degree than in thehorn type of speaker. The Duo-Rectronis a B battery eliminator that will supplyplate current for any receiver known tothe industry, even experimental types ofreceivers where as many as ten UV201Atubes are employed."

Sets R. C. A. Features

A brief description of the new R. C. A.apparatus follows:

Radiolas 30 is completely AC operatedand uses the new 8 -tube Super -Hetero-dyne. A self-contained Radiola Loud-speaker Model 100 of the Cone type isused, being driven by a rectifier -power -amplifier unit termed a "Multi-Rectron,"which provides plate, grid and filamentvoltages for the entire combination. Thisset therefore presents complete operationfrom 110 volt 60 cycle AC lighting circuits,eliminating all batteries. Requiring noantenna, the set operates from a self-con-tained loop, and according to the manu-facturer, provides unusual performanceunder the most exacting conditions im-posed by broadcast transmitting stations.

Another 8 -tube Super -Heterodyne is theRadiola 28, built in accordance with theconceptions of radio engineers who havemade a specialty of this type of circuit.Every element of the set has been de-signed and installed with a thought forsupreme sensitivity, selectivity and con-venience.

It operates in conjunction with a loopantenna which is mounted on the top ofthe cabinet which has sufficient space toaccommodate all of the necessary dry bat-teries, if used. The new uni-control tun-ing mechanism is employed in this instru-ment together with straight line frequencyvariable condensers giving equal spacingof channels on the tuning scale. A specialprotective tube (UV877) is used to protectthe set and Radiotrons from accidentalcontact with the high voltage B batteryleads.

When this set is used with Model 102loudspeaker, the set itself is dry bat-tery operated. The Loudspeaker, how-ever, is driven from the lighting mains.When used with model 104 Loudspeaker,the rectifier power -amplifier unit, which isa part of the Model 104 cabinet, may beconnected to the set by a special cable fur-nished with the equipment so that theyare both operated completely from A. C.lighting mains. The novelty of placingsuper -power loud -speakers at a distancefrom the broadcast receiver is a practicewhich is meeting with growing popularity.

The 6 -Tube "Super"Radiola 25, another of the new models

announced by the Radio Corporation ofAmerica, is a low-priced, 6 -tube Super -

DESK model of the new 8 -tubeSuper -Heterodyne circuit with suf-ficient space to accommodate all nec-essary batteries. No external con-nections required for antenna or

ground.

Heterodyne. It is, fundamentally, the well-known sectoid-harmonic circuit uponwhich improvements have been made andset is equipped with five UX 199 Radio-trons and one new Radiotron UX 120 drybattery, power amplifier. Space is pro-vided in the cabinet for housing all thebatteries.

The new RCA uni-control mechanism,with straight-line frequency condensers, isemployed. Thus, for most purposes, localor long distant stations may be tuned inby a single tuning control, thus giving themaximum refinement in tuning. The spe-cial protective tube (UV877) is also usedto protect the set and Radiotrons fromaccidental contact with the high voltageB battery leads. As in the case of allR. C. A. Super -Heterodynes, no antennais required, the loop mounted immediatelyon top of the case providing reception overextreme distances under favorable con-ditions.

When the Radiola 25 is used with theModel 102 loudspeaker, the set itself is drybattery operated. The loudspeaker, how-ever, is supplied with energy from a rec-tifier -power -amplifier unit (Uni-Rectron)which operates from the 110 -volt 60 cyclehouse lighting mains. When used withModel 104 loudspeaker a more powerfulrectifier -power -amplifier unit, which is apart of the Model 104 loudspeaker, may beconnected to the Radiola 25 by a special30 -ft. cable furnished with the set so thatRadiola 25 and the Loudspeaker unit arecompletely operated from 110 volt 60 cyclelighting mains.

Considerable interest has been shown inthe new Radiola 20, which is a non -radi-ating 5 -tube tuned radio frequency re-ceiver, with regeneration. It uses five dry -cell tubes, four of them being UX199s andthe fifth the new power amplifier for thelast audio stage, Radiotron UX120. Bat-teries are external to the set but are easilyconnected by means of a 5 ft. cable whichcontains all leads distinctively colored andplainly tagged.

The main distinguishing features aboutthis set are the combination of tuned radiofrequency with regeneration, which pro-vides greater sensitivity and selectivity,and the fact that there is but one maintuning control. On the. Radiola 20, as onthe new Super -Heterodynes, the tuningdials are a new departure from the ordi-nary type of dial. A large bakelite discwith knurled edge is mounted with themovable plates of tuning condensers. Asegment of the disc protrudes a fractionof an inch through a slot in the panel andis tuned by a ,slight pressure up or down.Mounted on the same shaft is a cylin-der, part of which shows through a win-dow in the panel. On this cylinder the lo-cation of the tuning points for all stationsis to be marked, and as the tuning valuesof Radiola 20 are constant, the stations canbe located at the same spot every timethey are tuned in.

20 RADIO WORLD April 17, 1926A THOUGHT FOR THE WEEK

AZZ,Jclassic music. recitations, talks,technical addressee-which! What's the

difference, so long as some of them arefavorites ttith a good percentage of listeners-mf Radio is not raw, nor will it ever be,for the few.

0 Domaom aws modaeowor

0 0 g fT. tasa Cows.. aseo I. Poos. aasoso

Reale World,* Mega, "A revile set fir ovary Immo..

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lima East ot Dr.adway,ROLAND BURKE HENNE.SSY. President

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March 0. 1619.

APRIL 17, 1926

A Simple Wavetrap

HERE is the set-up for a simplewavetrap. (Hayden).

How to Solve Problemof the Station N earby

THE number of persons living in loca-tions that require special receivers for

.siactory reception is still growing. Acar ago the growth was more rapid, as

new stations were being licensed, whereasin the last six months not one such hasbeen licensed. Every time a new stationopens it means that quite a number ofpersons have trouble.

In New York City, for instance, thereare too many stations with antennas inthe Borough of Manhattan, although ithas become fashionable and also profitableto remove the antenna to some open spacenot very far away, and send the programsfrom the metropolitan studio to the trans-mitter by telephone. At the transmittingplant the programs are "etherized" andbecome radio. This develops a new cropof sufferers, those who can not tune outthe newly located antenna. One mightsuppose that the burden merely has beentransferred, but such is not quite the case,for the congested Borough from whichthe antenna was moved still has an abund-ance of the same sort of interference, al-though from other stations.

It Is PainfulThe condition of those newly annoyed

by a neighboring transmitting aerial mayjustly be described as suffering:since radioreception is such a great joy that to haveit spoilt or severely circumscribed is in-deed painful. It is so no matter how gooda station moves its antenna across theway from your back yard. Take WJZ,for instance. That is undoubtedly one ofthe world's finest and greatest stations,from the excellence of its entertainingand educating programs, to the beautifulskill of its modulation. Yet if one is pre-cluded from hearing any station exceptone, however good that one may be, hehas a just grievance. What good is thedistance -getting set, if a neighboring an-tenna kills off even all the other locals?And why have a set that needs be tuned,when the only station it can tune in, whilethe interferer is on the air, is that station?A push-pull switch, fixed coils, fixed con-densers, tubes, sockets, batteries-andthere's your sett Talk about single con-trol! Zero control would answer the pur-pose

WJZ found itself up against severelocal opposition. The transmitter atBound Brook, N. J., often outputting50,000 watts, the greatest in the history ofAmerican broadcasting, behaved like amagnet, attracting vituperative letters.There was talk even of Federal legisla-tion to restrict the new monster of theair.

Kind Words from OthersOn the other hand, farmers and others

from far-off points, even cattle men onthe Plains, wrote that they were hearingWJZ regularly for the first time, andsuper power certainly won many friendsthus. Super power is sound economictheory, since it is too much to expect eventhe Radio Corporation of America to run.1 station with a steady daylight radius of30 miles or so, at $250,000 a year or more,when at a disproportionately increasedcost the area is trebled. Super powermeans sorrow for some, joy for many.Stations can not be expected to locatetheir aerials in the wilds, while the studiosare in the "tames."

The problem of final disposition bymunicipalities is something like that ofsuper power. Final disposition is a politename for the disposal of the population'sgarbage. Any mention of locating an in-cinerator near anybody's home, present

or prospective, is met with a howl of pro-test, yet urgent necessity compels sonicaction, and the good of the many shouldbe the controlling factor. The answer isthat incinerating plants filially are locatedsomewhere, just as radio transmitters finda place in the sun, at whatever spot.

Many DisgruntledThere must ever be the disgruntled, as

it is not pleasant to endure either annoy-ance-aerial or incinerator. In the muni-cipal problem, the only solution may befor the individual to move, but in regardto the radio question, this certainly wouldbe absurd, as the sufferers live in high-class residential districts, and residenceis more important than radio. Hence thequestion: What's to be done?

With a powerful or even non -powerfultransmitter close at hand, the sufferershould provide means for eliminating theinterferer.

The First RecommendationThe first suggestion inevitably is to in-

stall a wave trap. This consists of a vari-able condenser connected across a coil.The aerial is introduced at one end ofanother and smaller winding, while theend of the winding goes to the antennapost of the set. By setting the condenserSO that the trap circuit is tuned to thewave of the interferer, this wave is ab-sorbed by the trap, and the actual receiv-ing circuit is left free to bring in otherstations, without crosstalk from theneighboring one. This is beautiful theory,but where the station is using 50,000watts, or even 1,500 watts, anything likeproximity to impossible totrap out the interference in this manner.The best that can be expected undermost of the adverse conditions is thatthe volume of the interference will declineconsiderably, which it is bound to do, andperhaps other stations may be heard with-out audible interference, while they aresending, even though a moment's silencefrom that source might enable one tohear the undertone of the interferer.Such a solution should be satisfactoryenough, indeed it is no more than mostof the complainants ask, but one mustlive perhaps a mile or so from the station.

Where Matters Are WorseFor the severer cases the same sort of

wave trap, but used in conjunction withan extra tube, and with a variometer inthe plate circuit, will give very much bet-ter results. This is known as the RiderWave Trap and was described in theDecember 26 issue of RADIO WOiDaD. It isin reality a 1 -tube regenerative set, usedas a wave trap, hence a regulation setmay be employed by those who do notcare to build their own, e.g., a CrosleyPup. As the Radio Corporation ofAmerica owns WJZ and also is a licenseeunder the regenerative patent, it is sur-prising that the corporation does notmarket such a regenerative trap, and stopthe appeals and trips to Washington.

The Better SetAnother method of attacking the prob-

lem of such interference is by supplantingone's present set with a far more selective,hence more rigorously excluding one. Astage of tuned radio frequency amplifica-tion ahead of a Super -Heterodyne re-ceiver, or a regenerative wave trap usedin conjunction with a Super -Heterodyne,will do the trick. The TRF Super Heter-odyne may well be along the lines estab-lished by Leo Fenway, and described inthe February 6, 13, 20 and 27 issues of


April 17, 1926 R A D10 \\ R 1. I)

THE RADIO TRADE Literature Wanted

No Fear of a Monopoly,

WASHINGTONRepresentative Arthur M. Free recently

gave the following data on the absenceof danger of a radio monopoly, incorpo-rating interesting trade information:

"In my judgment we already have suffi-cient governmental machinery to preventmanufacturing monopoly. The FederalTrade Commission and the courts canstop any monopoly under the laws al,ready in existence, and the InterstateCommerce C6mmission has full jurisdic-tion in the matter of rates.

"We have today some 35 manufacturersof tubes, 350 manufacturers of sets, and1,600 manufacturers of radio parts.

"In 1925 the Radio Corporation soldabout one -tenth of the radio apparatussold in the United States.

"There are many very dependable radiosets on the market today in addition tothose made by the Radio Corporation,such as the sets made by the CrosleyRadio ,Corporation, the Atwater KentManufacturing Co., A. H. Grebe & Co. Infact, the Radio Corporation is third inthe sale of sets.

"In the year 1925 the Radio Corporationsold over 16,000,000 tubes, of which only

(Concluded from page 20)RADIO WoRLD. The Fenway, properlybuilt, tunes out WHN, New York, at apoint of reception right next door to thestation. Other well -constructed Super -Heterodynes will do the same, e.g., theRadiola line and the Victoreen, the lattera home -constructed receiver. But ofcourse WHN does not use 50,000 watts,indeed only a hundredth of that.

All over the United States and in manyparts of Canada are radioists who sufferfrom station interference along the linesdiscussed, and the same remedies areapplicable to them.

Cheap Sets Won't Do ItIt is idle to attempt to find satisfaction

in a cheap and poorly built set of indiffer-ent design where one is so unfortunatelylocated, although quite a few fans besiegedealers with demands that sets that sellfor a few dollars do more in the directionof elimination than do the best receiverson the market or within the scope ofhome construction. Asking too much isa favorite pastime of a few, or perhapsof many. A prospective purchaser beginsby reciting his grievance against the of-fender and demanding that he be sold aset, say for $35, that will tune out locals,including the transmitter next door, andbring in DX. While fans may be par-doned this over -expectancy, dealers whOencourage them in the belief that anordinary set will meet these demandsdeserve censure. And indeed they get it-when the customer comes back withthe set!

Business OpportunitiesRadio and Electrical

Rates 110 per word; Minimum, $1.00; Cashwith order

WELL-KNOWN FURNITURE INSTALMENTHOUSE DESIRES TO LEASE OUT ITS RADIODEPARTMENT; PERMANENT WINDOW DIS-PLAY AND AMPLE FLOOR SPACE; ONLYEXPERIENCED RETAIL RADIO MAN WILLBE CONSIDERED; NO BEGINNERS; RE-SPONSIBLE PARTY WITH PERSONALCREDIT RATING; CASH GUARANTEE WILLBE ESSENTIAL; VICTOR AGENCY IN-CLUDED. BOX 292, 228 WEST 421), N. Y. C.

1,620,640 were to equip its own sets and15,537,446 were for sets made by othermanufacturers and for replacements.

"In 1925 the Radio Corporation soldtubes direct to 40 different set manufac-turers-the total number of tubes sold tothem being 1,363,150, or nearly as manyas those sold by the Radio Corporationitself in connection with its own sets.Practically all the other manufacturerssold their sets without tubes but equippedwith standard sockets for the insertionof tubes by the purchasers.

"The stock of the Radio Corporation ofAmerica is owned today as follows:

Per CentBy the General Electric Co 15.68By the Westinghouse Elec. & Mfg

Co. 6.63By individuals allied with the

Westinghouse interests 9.69By various other stockholders, ap-

proximately 33,000 in number 68.00

Jobbers and Dealersto Visit Radio Center

More than a thousand radio dealers andjobbers from every part of the countryhave requested admission passes to theRadio Center, Bush Building, New YorkCity, says Col. S. H. Mapes, president ofthe Center.

With this intense interest in the Centerdisplayed almost a month before the for-mal opening date it is expected that thenumber of dealers and jobbers visitingthe Center during 1926 will be even greaterthan had been originally expected by theofficials of the organization.

Twenty thousand dealers a year areestimated as the total number of visitorsto New York radio concerns, and a largeportion of these will likely come to othereastern buying centers during the springand summer months.

Knockdown ConsoleA new line of consoles for those who

wish to beautify their radio sets has nowbeen placed on the market. A strikingfeature is that they are knockdown andcan be easily and quickly put together byanyone without the aid of bolts, nails,screws or glue. At the same time thefinished product is strong and rigid. Thefinish is rich American walnut or mahog-any on Southern gum wood. The No. 6size is 36" high by 34" long, 141/2" wide.Panel sizes fit any set from 7x12" to7x30". Full information and pictures maybe had from Cleverly & Cross, 321 Broad-way, New York City. Mention RADIOWORLD.

THE swie of readers of RADIO WORLDwho desire literature from radio lob-ber dealer. are published in RADIO

WORLD on request of the reader. Theblank below may be used. or a post cardor letter will do instead.Trade Service Editor.RADIO WORLD145 West 45th St., N. Y. at).

I desire to receive radio literature.NameCity or townState .Are you a dealer?

11 not, who le your dealer?Hia NameHis Address

H. R. Mercadal, 315 U. S. Custom HouseNew Orleans, La.F. Wilhelmi, $ Pine St., Boston, Mass.E. Nelson, Alexandria Bay, N. Y.Chas. A. Fisher, Selinsgrove, Pa. (Dealer).F. P. Senors, :0154 Montgomery Road, Shaken

Heights, Cleveland, 0.The Radio Shoppe, 1836 N. Bond St., Balti-

more, Md. (Dealer).C. A. Halsterd, 5716 Normal Boulevard, Chicago,

DI. (Dealer).Donald Hiller, 6614 South Sacramento Ave.,

Chicago, EL (Dealer).A. 1(arsch, 2177 Pacific St., Brooklyn, N. Y.William Smith, 58 Grant St., Akron, 0,M. J. Claypoole, Kittanning, Pa. (Dealer).C. H. Bradbrook, 116 N. Topping St., Kansas

City, Mo.J. A. Cronin, 1 Wilcox St., Worcester, Mass.Arthur McKelson, Valley City, N. D.W. J. Lyons, 3E04 Prytania St., New Orleans,

La. (Dealer).Wesley A. Scott, 117 Lark St., Albany, N. Y.M. D. Frink, 717 Central Ave., Charlotte,

N. C. (Dealer).Chas. Apgar, Fairmount, N. J. (Dealer).

United States Is UniqueIn Absence of Radio Fee

The public in the United States today isin a unique position. Anyone can makehis own set and listen in on a programwithout charge. This is not true of anyother large country. Great Britainlicenses both sending and receiving setsand collects through the British Broad-casting Company a certain percentage ofthe sale price of each piece of apparatusand limits the number of broadcastingstations. Canada, under its Minister ofMarines and Fisheries, licenses bothbroadcasting and receiving sets. Aus-tralia levies a tax on receiving sets.

A Selling PointDo you realize that no one would be

without a radio if he knew about the won-derful things now on the air? Here aresome of the headliners appearing on theprograms :

President Coolidge, Ignace Paderewski,Joseph Hofmann, John McCormack,Walter Damrosch, Arturo Toscanini,Mme. Schumann-Heink, Mary Garden,Titta Ruffo, Frances Alda, Louise HomerTito Schipa, Irvin S. Cobb, Will Rogers,Philharmonic Orchestra, and U. S. MarineBand.-Radio Retailing.

Why So Many Who Knock?It seems only yesterday, although it is

possibly a year ago, that department storesin page advertisements were telling of theterrible sacrifices on Freed-Eisemann setsand how their neutrodyne sets were beingretailed at less than manufacturer's costs.

At the time there were many uncon-firmed rumors not only of distress of radiomanufacturers. Now Joseph D. R. Freedsays that the Freed-Eisemann Radio Com-pany has no debts of any kind and have

cash in the bank and on hand of $523,610.How many businesses can show a finerstatement than this? Many radio manu-facturers are in equally good condition.Why should the radio industry have moreknockers than any other?

No industry is progressing so rap-idly as radio and holds such a bright fu-ture for the coming year. Any concernproducing good radio apparatus at a fairprice cannot help meet with success.

22 RADIO WORLDNew Plug Controls

Both Tone and Volume

THE volume control.AN adequate volume control is needed

now more than ever before. If therheostats are turned low, volume will bereduced, but perhaps at the expense ofclarity. If turned too low on the audioside, distortion results. Partially detuningthe receiver helps, but in this day of con-gested broadcasting, such a procedurewill usually result in interference betweenstations.

Several of the best radio receivers in-corporate a tone control on the panel.Now an accessory has just been marketedthat provides successful control of toneand volume and can be added to any re-ceiver by the simple expedient of sub-stituting it for the old loud speaker plug.It is called a Modulator Plug and ismanufactured by the Central Radio Lab-oratories of Milwaukee. The size is littlelarger than that of a standard phone plug.Inside the body of the plug is a non -inductive graphite type of variable resist-ance controlled by means 'of a small knobon the plug. When attached to the re-ceiver, it provides an additional tone con-trol that can be adjusted to give any de-gree of tone volume from a whisper rightup to maximum.

An outstanding advantage of this typeof control is the apparent reduction ofstatic interference. As volume is reducedby turning the knob, the signal to staticradio seems to increase, until a point isreached where the program can be en-joyed without either detuning the set orreducing the filament pressure below thetemperature needed for best reproduction.

Little Sleep, Much Speed,Ted Nelson's Easy Task

MED NELSON, co -director and an-nouncer, WMCA, New York City

is an expert on re-mote control, andsucceeded in some ofthe most difficulttasks undertalcen inthis line anywhere inthe country. Every-thing has to work otftjust exactly on time,or Nelson's task is afizzle. By carrying amicrophone and standwith him as a pre-caution, and going inheavily for fast taxirides, he achievesthat synchrony of TED NELSONtime and place that (Harald Stein Photo).makes him successful. Often he has towork 12 hours a 'lay. On one occasionhe went without sleep for 36 hours. Andit was not a case of insomnia. He says:

"Employes who close down their desksand rush into their street coats promptlyat 5.30 P. M., no matter how much workremains to be done, should get a job asa radio installation supervisor on remotecontrol work."

Uri DIAMOND OF THE AIR BOOKLET withfull instructions to make the Diamond. with blueprint. SOc. Newsdealers and radio dealers anget supply from American News Co. and Itsbranches. RADIO WORLD. 14S W. 45th St.,N. Y. C.

Homes Exhibit Compares Sp

THE AMPLIFYING control room, from which visitors to_he Ideal HoiosExhibition in Olympia, London, were supplied with musk and education-,entertainment and demonstration of speakers. Station 2L0 b dcast the aptprograms. These were caught by the receiver at the left an I en amplitiec

the apparatus at the right. (Katie) & Hcrbe

Madison Square GardenStation Goes on the Air

Madison Square Garden's new stationWMSG was opened officially with a pro-gram of speeches and music. The stationoperates on a 212.6 -meter wavelength.Speakers at the inaugural included TexRickard, John Ringling and James A. Far-ley of the State Athletic Commission.

In tests conducted prior to the officialopening programs were picked up in Cali-fornia and Texas, according to lettersreceived at the studio.

Walter J. Neff is studio director andannouncer; J. Bernhart, manager, and E.W. Dannals, chief engineer of the new sta-tion. The station will devote itself pri-marily to broadcasting sporting events.

Tuning Fork FrequencySteadied by New Device

WASHINGTONThe Electrical Division of the Bureau

of Standards reports that a new method,exceptionally accurate, has been developedto measure the frequency of tuning forks,used by broadcasting stations and others.

The old system of driving the tuningfork by the "make and break" methodhas been done away with, and an ar-rangement whereby a "continual drive"is substituted, which gives much greateraccuracy.

Prof. Hazeltine Patentsthe Sacred Angle of CoilsProf. Louis A. Hazeltine, inventor of

the Neutrodyne, has obtained patents onthe placement of coils at angles to preventinductive feed back and interplay of fields.The 57 degree Neutrodyne angle and theright angle are covered, in fact virtuallyall angles.

TWO STATIONS FOR INDIAWASHINGTON

The Indian Radio Telegraph Co. is plan-ning the construction of a 12 -kw. broad-casting station at Calcutta, according toa consular report to the Department ofCommerce. It is understood this is one oftwo stations to be built in India, theother to bj Bomhs

New CzechOpens c

The new broadcanice -Prague was reation, states a repcof Commerce ironJ. F. Hodgson, Pr,

The internationanew station is OKan American firmwavelength. Theis 5 kw.

During the weekopening of the newbroadcasted for thethe development of

The Ministry ofannounced a broadcof 15 Czechoslovakper month, a considnumber of broadcCzecho-Slovakia wa

-'Ti

' letersStras-oper-

useh a 513 L.er at the antenna

1:owing the officialation lectures were-pose of stimul-Fp in this c,s s and Telting subscriptim,owns (or 30 cents)He reduction. The

ing subscribers inastimated at 30 000.

His Best in 1. rears,Fan Sa ; of 4 -Tuber

RESULTS EDITOR:

Can't we rename tur latest circuit byEdgar Collin "The fficiency Four?" Itsure is a whiz, knot ut and-well, wordsfail me. You can c -it on me as one ofyour boosters for a circuit and yourmagazine. Neither n be beat that's all.The set (described, March 27 issue)pick stations off onll waves with greatefficiency and DX.

In my twelve yea of radio this is thebest circuit I haA been able to gethold of.

R. H. LUCAS,.1217 Jackson Ave.,

Wichita, Kans.

Specializ on S -C 4Radio Mail Orde -louse is putting out

a special value in parts for the newS -C 4 -tube Single C -trol. The best partsare used as specifies ,y Silver and Cock-aday. This concernms literature on thisand other interesti radio lines, whichmay he had from t by addressing P.0. Box 129, Times aware Station, NewYork City. Mentio RADIO WORLD.

April 17, 1926 RADIO WORLD21

THE RADIC TRADE Literature Wanted

4-.

No Fear of a lionopoly,Says Free, r.ting Sales

WASHINGTONRet - Arthur M. Free recently

gav, ng data on theof dal. radio monopoly. t -

rating Mit:. (,ing trade information :"In my judgment we already have soli-

oient governmental machinery to prev,":.:manufacturing monopoly. The Fed, .(1Trade Commission and the court -

stop as' poly under the -

ready 'flee, and the I'Comm, .ission hastion in t or of rates.

"We have today some 35 mann('of tubes, 350 manufacturers of -(

1,600 manufacturers of radio par- -"In 1925 the Radio Corpori.- -H.

about on of the radiosold in I States."Thee(' very deper -

sets on t. ...r.et today inthose made by the Radio (-

such as the sets made byRadio Corporation, theManufacturing Co., A. Hfact, the Radio Corporthe sale of sets.

In the year 1925 thesold over 16,000,000 tubes.

(Concluded from page _RADIO Wry The Fenway.built, tur. HN, New 1'point of r right nextstation. Ot.. ::ell -constructedHeterodynes will do the same, e.rr.,Radiola line and the Victoreen, the lattera home -constructed receiver. But etcourse WHN does not use 50,000indeed only a 1:iindredth of that.

All over .1 States and in mar. --parts of radioists who ;:(--from statio. arence along thediscussed, anu the same remediesapplicable to them.


in a cheap anus riy built set of indiffer-ent design e is so unfortunatelylocated, Si ,e a few fans besiezedealers with -Is that sets that sellfor a few dollars do more in the directionof elimination than do the best receiverson the market or within the scope ofhome construction. Asking too much isa favorite pastime of a few, or perhapsof many. A prospective purchaser beginsby reciting his grievance against the of-fender and demanding that he be sold aset, say for $35, that will tune out locals,including the transmitter next door, andbring in DX. While fans may be par-doned this over -expectancy, dealers whoencourage them in the belief that anordinary set will meet these demandsdeserve censure. And indeed they get it-when the customer comes back withthe sett


word; Minimum, $1.00; Cashwith cederWELL/MOWN

FURNITURE INSTALMENTHOUSE DESIRESTO LEASE OUT ITS RADIODEPARTMENT-,

PERMANENT WINDOW DIS-PLAY ANDAMPLE FLOOR SPACE; ONLYEXPERIENCED

RETAIL RADIO MAN WILLBE CONS1DF.RED;NO BEGINNERS; RE-SPONSIBLE

PARTY WITH PERSONALCREDIT RATING;CASH GUARANTEE WILLBE ESSENTIAL;

VICTOR AGENCY El-CLUDED.BOX 292, 228 WEST 42D, N. Y. C.

Rates is.

0 were to equip its own sets and46 were for sets made by othercturers and for replacements.925 the Radio Corporation soldirect to 40 different set manufac-

-the total number of tubes sold to(eing 1,363,150, or nearly as manye sold by the Radio Corporationn connection with its own sets.ally all the other manufacturersir sets without tubes but equippedandard sockets for the insertion

- by the purchasers.stock of the Radio Corporation of

1. is owned today as follows:Per Cent

General Electric Co 15.68Westinghouse Elec. & Mfg

6.63:duals allied with theighouse interests 9.69us other stockholders, ap-lately 33,000 in number 68.00

"rs and Dealersto Visit Radio Centerhan a thousand radio dealers androm every part of the countryuested admission passes to theinter, Bush Building, New York

Col. S. H. Mapes, president ofr.

-us intense interest in the Centeralmost a month before the for-

ing date it is expected that theof dealers and jobbers visitinga during 1926 will be even greaterbeen originally expected by thef the organization.

thousand dealers a year areas the total number of visitors

-ork radio concerns, and a largepor. these will likely come to other

'lying centers during the springter months.

ickdown Consoleline of consoles for those who

with -autify their radio sets has nowbeen t -2d on the market. A strikingfeature that they are knockdown andcan be lily and quickly put together byanyone ithout the aid of bolts, nails,screws glue. At the same time thefinished -oduct is strong and rigid. Thefinish is eh American walnut or mahog-any on authern gum wood. The No. 6size is high by 34" long, 141/2" wide.Panel us fit any set from 7x12" to7x30" 11 information and pictures maybe had m Cleverly & Cross, 321 Broad-way, 1 York City. Mention RADIOWOOL

THE images of readers of RADIO WORLDwho desire literature from radio Job-

ber. and dealers are published in RADIOWORLD on request of the reader. Theblank below may be used. or post cardor letter will do instead.Trade Service Editor.RADIO WORLD,145 West 45th St.. N. Y. City.

I desire to receive radio literature.Name

City or townStateAre you a dealer?

If not, who la your dealer?His NameHie Address

H. R. Mercadal, 315 U. S. Custom HouseNew Orleans, La.F. Wilhelmi, 5 Pine St., Boston, Mass.E. Nelson, Alexandria Bay, N. Y.Chas. A. Fisher, Selinsgrove, Pa. (Dealer).F. P. Scruers, 2854 Montgomery Road, ShakenHeights Cleveland, 0.TheRadio Shoppe, 1836 N. Bond St., Balti-more, Md. (Dealer).C. A. Halsterd, 5716 Normal Boulevard, Chicago,

Ill. (Dealer).Donald Hiller. 6614 South Sacramento Ave.,

Chicago, Ill. (Dealer).A. Karsch, 2177 Pacific St., Brooklyn, N. Y.William Smith, 58 Grant St., Akron. 0.M. J. Claypoole Kittanning, Pa. (Dealer).C. H. Bradbroofe, 116 N. Topping St., Kansas

City, Mo.J. A. Gronin, 1 Wilcox St., Worcester, Mass.Arthur McKelsou, Valley City, N. D.W. J. Lyons, 3824 Prytania St., New Orleans,





A Selling PointDo you realize that: no one would be

without a radio if he knew about the won-derful things now on the air? Here aresome of the headliners appearing on theprograms:


Wiy So Many Who Knock?It see only yesterday, although it is cash in the bank and on hand of $523,610.

possibly ..'ear ago, that department stores How many businesses can show a finer

in page vertisements were telling of the statement than this? Many radio manu-terrible zrifices on Freed-Eisemann sets facturers are in equally good condition.and how-teir neutrodyne sets were being Why should the radio industry have moreretailed less than manufacturer's costs. knockers than any other?

At the time there were many uncon- No industry is progressing so rap -

firmed rors not only of distress of radio idly as radio and holds such a bright fu-manufar-rers. Now Joseph D. R. Freed ture for the coming year. Any concernsays thane Freed-Eisemann Radio Corn- producing good radio apparatus at a fairpany ha_ao debts of any kind and have price cannot help meet with success.

20 RADII) \\.()RLD - -

April 17, 1926

Par Agate Line

A THOUGHT FOR THE WEEKT AZZ, classic music, recitations, talks,J technical addresses-which? What's the

difference, so long as some of them arefavorites with a good percentage of listeners-in? Radio is not raw, nor will it ever be,for the few.

Radio World', Slogan: "A radio set for every home."

TELEPHONE BEYANT 0558. 0559PI:BLIMP:0 EVERY WEDNESDAY

(Dated Saturday of same week)FROM PUBLICATION OFFICE

HENNESSY RADIO PUBLICATION CORPORATION195 WEST 95th STREET, NEW YORK, N. Y.

(Just East of Broadway)ROLAND BURKE HENNESSY. President

51. B. HENNESSY. Vice -PresidentFRED S. CLARK, Secretary and Manager

European Representatives: The International News Co.Breams Bides., Chancery Lane, London, Eng.

Paris, France: Brentano's. 8 Avenue de l'OperaSan Francisco: Lloyd B. Chappell, 858 O'Farrell St.

EDITOR. Roland Burke HennessyMANAGING EDITOR, Herman BernardTECHNICAL EDITOR, Lewis Winner

CONTRIBUTING EDITORS, John F. Rider, J. E. Andersen

SUBSCRIPTION RATESFifteen cents a copy. $0.00 a year. $3.00 for ex

months. $1.50 for three months. Add $1.00 a yearextra for foreign postage. Canada, 50 cents.

Receipt by new subscibers of the first copy of RADIOWORLD mailed to them after sending In their order ISautomatic acknowledgment of their subscription order.Changes of address should be received at this office twoweeks before date of publication. Always give old address:also state whethrr subecription Is new or a renewal.

ADVERTISING RATESGeneral Advertising

1 Page, 7'4 "nil" 982 lines $300.0034 Page. 7 %"15 Ye" 231 lines 150.00% Page, VA" D. C. 231 lines 150.00% Page, 9 %" D. C. 115 lines 75.001 Column, 2%":11" 154 lines 100.001 Inch

10. A00d

Time Discount52 consecutive issues 20%28 times consecutively or E. 0. W. one year 1E%4 consecutive issues 10%

WEEKLY, dated each Saturday, published Wednesday.Advertising forms close Tuesday, eleven days in AdValleof date of issue.

CLASSIFIED ADVERTISEMENTSTen cents per word. Minimum 10 words. Cash with

order. Business Opportunities ten cents per word, $1.00minimum.

Entered es second.elass matter March 23, 1522. atthe Post Office at New York, N. Y., under the Act ofMarch 3, 1879.

APRIL 17, 1926

A Simple Wavetrap

HERE is the set-up for a simplea vet ra p. (Hayden).


1HE number of persons living in loca-tions that require speoial receivers for

satisfactory reception is still growing. Ayear ago the growth was more rapid, asnew stations were being licensed, whereasin the last six months not one such hasbeen licensed. Every time a new stationopens it means that quite a number ofpersons have trouble.



by a neighboring transmitting aerial mayjustly be described as suffering; since radioreception is such a great joy that to haveit spoilt or severely circumscribed is in-deed painful. It is so no matter how gooda station moves its antenna across theway from your back yard. Take WJZ,for instance. That is undoubtedly one ofthe world's finest and greatest stations,from the excellence of its entertainingand educating programs, to the beautifulskill of its modulation. Yet if one is pre-cluded from hearing any station exceptone, however good that one may be, hehas a just grievance. What good is thedistance -getting set, if a neighboring an-tenna kills off even all the other locals?And why have a set that needs be tuned,when the only station it can tune in, whilethe interferer is on the air, is that station?A push-pull switch, fixed coils, fixed con-densers, tubes, sockets, batteries-andthere's your set! Talk about single con-trol! Zero control would answer the pur-pose I



from far-off points, even cattle men onthe Plains, wrote that they were hearingWJZ regularly for the first time, andsuper power certainly won many friendsthus. Super power is sound economictheory, since it is too much to expect eventhe Radio Corporation of America to runa station with a steady daylight radius of30 miles or so, at $250,000 a year or more,when at a disproportionately increasedcost the area is trebled. Super powermeans sorrow for some, joy for many.Stations can not be expected to locatetheir aerials in the wilds, while the studiosare in the "tames."


or prospective, is met with a howl of pro-test, yet urgent necessity compels someaction, and the good of the many shouldbe the controlling factor. The answer isthat incinerating plants finally are locatedsomewhere, just as radio transmitters finda place in the sun, at whatever spot.

Many DisgruntledThere must ever be the disgruntled, asit is not pleasant to endure either annoy-

ance-aerial or incinerator. In the muni-cipal problem, the only solution may befor the individual to move, but in regardto the radio question, this certainly wouldbe absurd, as the sufferers live in high-class residential districts, and residenceis more important than radio. Hence thequestion: What's to be done?



stall a wave trap. This consists of a vari-able condenser connected across a coil.The aerial is introduced at one end ofanother and smaller winding, while theend of the winding goes to the antennapost of the set. By setting the condenserso that the trap circuit is tuned to thewave of the interferer, this wave is ab-sorbed by the trap, and the actual receiv-ing circuit is left free to bring in otherstations, without crosstalk from theneighboring one. This is beautiful theory,but where the station is using 50,000watts, or even 1,500 watts, anything likeproximity makes it next to totrap out the interference in this manner.The best that can be expected undermost of the adverse conditions is thatthe volume of the interference will declineconsiderably, which it is bound to do, andperhaps other stations may be heard with-out audible interference, while they aresending, even though a moment's silencefrom that source might enable one tohear the undertone of the interferer.Such a solution should be satisfactoryenough, indeed it is no more than mostof the complainants ask, but one mustlive perhaps a mile or so from the station.


wave trap, but used in conjunction withan extra tube, and with a variometer inthe plate circuit, will give very much bet-ter results. This is known as the RiderWave Trap and was described in theDecember 26 issue of RADIO WORLD. It isin reality a 1 -tube regenerative set, usedas a wave trap, hence a regulation setmay be employed by those who do notcare to build their own, e.g., a CrosleyPup. As the Radio Corporation ofAmerica owns WJZ and also is a licenseeunder the regenerative patent, it is sur-prising that the corporation does notmarket such a regenerative trap, and stopthe appeals and trips to Washington.






No Fear of a Monopoly,Says Free, Citing Sales



"In my judgment we already have suffi-cient governmental machinery to preventmanufacturing monopoly. The FederalTrade Commission and the courts canstop any monopoly under the laws al,ready in existence, and the InterstateCommerce Coinmission has full jurisdic-tion in the matter of rates.



"There are many very dependable radiosets on the market today in addition tothose made by the Radio Corporation,such as the sets made by the CrosleyRadio .Corporation, the Atwater KentManufacturing Co., A. H. Grebe & Co. Infact, the Radio Corporation is third inthe sale of sets.


(Concluded from page 20)RADIO WORLD. The Fenway, properlybuilt, tunes out WHN, New York, at apoint of reception right next door to thestation. Other well -constructed Super -Heterodynes will do the same, e.g., theRadiola line and the Victoreen, the lattera home -constructed receiver. But ofcourse WHN does not use 50,000 watts,indeed only a hundredth of that.



in a cheap and poorly built set of indiffer-ent design where one is so unfortunatelylocated, although quite a few fans besiegedealers with demands that sets that sellfor a few dollars do more in the directionof elimination than do the best receiverson the market or within the scope ofhome construction. Asking too much isa favorite pastime of a few, or perhapsof many. A prospective purchaser beginsby reciting his grievance against the of-fender and demanding that he be sold aset, say for $35, that will tune out locals,including the transmitter next door, andbring in DX. While fans may be par-doned this over -expectancy, dealers whiiencourage them in the belief that anordinary set will meet these demandsdeserve censure. And indeed they get it-when the customer comes back withthe sett


Rates Ho per word; Minimum, $1.00; Cashwith order

WELL-KNOWN FURNITURE INSTALMENTHOUSE DESIRES TO LEASE OUT ITS RADIODEPARTMENT, PERMANENT WINDOW DISPLAY AND AMPLE FLOOR SPACE; ONLYEXPERIENCED RETAIL RADIO MAN WILLBE CONSIDERED; NO BEGINNERS; RE-SPONSIBLE PARTY WITH PERSONALCREDIT RATING; CASH GUARANTEE WILLBE ESSENTIAL; VICTOR AGENCY IN-CLUDED. BOX 292, 228 WEST 47D, N. Y. C.


"In 1925 the Radio Corporation soldtubes direct to 40 different set manufac-turers-the total number of tubes sold tothem being 1,363,150, or nearly as manyas those sold by the Radio Corporationitself in connection with its own sets.Practically all the other manufacturerssold their sets without tubes but equippedwith standard sockets for the insertionof tubes by the purchasers.











wish to beautify their radio sets has nowbeen placed on the market. A strikingfeature is that they are knockdown andcan be easily and quickly put together byanyone without the aid of bolts, nails,screws or glue. At the same time thefinished product is strong and rigid. Thefinish is rich American walnut or mahog-any on Southern gum wood. The No. 6size is 36" high by 34" long, 141/2" wide.Panel sizes fit any set from 7x12" to7x30". Full information and pictures maybe had from Cleverly & Cross, 321 Broad-way, New York City. Mention RADIOWORLD.

THE sanie of readers of RADIO WORLDwho desire literature from radio Job-

bers and dealers are published in RADIOWORLD on request of the reader. Theblank below may be used, or a post cardor letter will do instead.Trade Service Editor,RADIO WORLD.145 West 45th St.. N. Y. City.


City or townState

Are you a dealer?11 not, who is your dealer?

His NamHis Address

H. R. Mercadal, 315 U. S. Custom HouseNew Orleans, La.F. Wilhelmi, 6 Pine St., Boston. Mass.

BE. Nelson, Alexandria ay, N. Y.Chas. A. Fisher Selinsgrove, Pa. (Dealer).F. P. Scruers, 2654 Montgomery Road, Shaken

Heights Cleveland. 0.TheRadio Shoppe, 1836 N. Bond St., Balti-more, Md. (Dealer).C. A. Halsterd, 5716 Normal Boulevard, Chicago,

131. (Dealer).Donald Hiller, 6614 South Sacramento Ave.,

Chicago, BL (Dealer).A. Karsch, 2177 Pacific St., Brooklyn, N. Y.William Smith, 58 Grant St., Akron, 0,M. J. Claypoole, Kittanning, Pa. (Dealer).C. H. Bradbrook, 116 N. Topping St., Kansas

City, Mo.J. A. Gronin, 1 Wilcox St., Worcester, Mass.Arthur McKelson,' Valley City, N. D.W. J. Lyons, 3824 Prytania St., New Orleans,

La. (Dealer).Wesley A. Scott, 117 Lark St., Albany, N. Y.M. D. Frink, 717 Cential Ave.,i Charlotte,










cash in the bank and on hand of $523,610.How many btisinesses can show a finerstatement than this? Many radio manu-facturers are in equally good condition.Why should the radio industry have moreknockers than any other?


20-.-

RADIO WORLD April 17, 1926

e.

Per Agate Line

A THOUGHT FOR THE WEEKT AZZ, classic music, recitations, talks,

technical addresses-which? What's thedifference, so long as some of them arefavorites with a good percentage of listeners-in? Radio is not row, nor will it ever be,for the few.

A @sofaDutnbutor end 11und Wen,

CO

Radio World's Slogan: .91 rodlo set for every horde!.

TELEPHONE BRYANT 0558. 0559PUBLISHED EVERY WEDNESDAY

(Dated Saturday of same week)FROM PUBLICATION OFFICE

HENNESSY RADIO PUBLICATION CORPORATION145 WEST 45th STIVE171`, NEW YORK, N. Y.

(Just East of Broadway)ROLAND BURKE HENNESSY, President

M. B. HENNESSY. Vice.PresidantFRED S. CLARK, Secretary and Manager

European Representatives: The International News CO.Breams Bldg., Chancery Lane, London, Eng.

Paris. France: Brentano's. 8 Avenue de VCIDersSan Francisco: Lloyd B. Chappell, 656 O'Farrell St.

EDITOR, Roland Burke HennessyMANAGING EDITOR, Herman BernardTECHNICAL EDITOR, Lewis Winner

CONTRIBUTING EDITORS, John F. Rider, J. E. Anderson

SUBSCRIPTION RATESFifteen cents a copy. $6.00 a year. $3.00 for six

months. $1.50 for three months. Add $1.00 a yearextra for foreign postage. Canada. 50 cents.

Receipt by new subscibers of the first copy of RADIOWORLD mailed to them after sending in their orderautomatic acknowledgment of their subscription order.Changes of address should he received at this office twoweeks before date of publication. Always give old address;also state whether subscription Is new or a renewal.

ADVERTISING RATESGeneral Advertising

1 Page, 7,4,,,,,. 962 lines 5300.00% Page, 7 1/4"15%" 231 lines 150.00% Page. 8)4" D. 0. 231 lines 150.00% Page, 4 %" C. 115 lines 75.001 Column. 2%"D.x11" 154 lines 100.001 Inch 10.00

.75Time Discount

52 consecutive issues 20%26 times consecutively or E. 0. W. one year 15%

consecutive issues 10%WEEKLY, dated each Saturday, published Wednesday.

Advertising forms close Tuesday. eleven days in advanceof date of issue.

CLASSIFIED ADVERTISEMENTSTen cents per word. Minimum 10 words. Cash with

order. Business Opportunities ten cents per word, $1.00minimum.

Entered as second-class matter March 23, 1922, atthe Post Offlre at New York, N. Y.. under the Act ofMarch 9, 1879.

APRIL 17, 1926

A Simple Wavetrap

HERE is the set-up for a simplewavetrap. (Hayden).


1HE number of persons living in loca-tions that require speoial receivers for

satisfactory reception is still growing. Ayear ago the growth was more rapid, asnew stations were being licensed, whereasin the last six months not one such hasbeen licensed. Every time a new stationopens it means that quite a number ofpersons have trouble.



by a neighboring transmitting aerial mayjustly be described as suffering, since radioreception is such a great joy that to haveit spoilt or severely circumscribed is in-deed painful. It is so no matter how gooda station moves its antenna across theway from your back yard. Take WJZ,for instance. That is undoubtedly one ofthe world's finest and greatest stations,from the excellence of its entertainingand educating programs, to the beautifulskill of its modulation. Yet if one is pre-cluded from hearing any station exceptone, however good that one may be, hehas a just grievance. What good is thedistance -getting set, if a neighboring an-tenna kills off even all the other locals?And why have a set that needs be tuned,when the only station it can tune in, whilethe interferer is on the air, is that station?A push-pull switch, fixed coils, fixed con-densers, tubes, sockets, batteries-andthere's your set! Talk about single con-trol! Zero control would answer the pur-pose!



from far-off points, even cattle men onthe Plains, wrote that they were hearingWJZ regularly for the first time, andsuper power certainly won many friendsthus. Super power is sound economictheory, since it is too much to expect eventhe Radio Corporation of America to runa station with a steady daylight radius of30 miles or so, at $250,000 a year or more,when at a disproportionately increasedcost the area is trebled. Super powermeans sorrow for some, joy for many.Stations can not be expected to locatetheir aerials in the wilds, while the studiosare in the "tames."


or prospective, is met with a howl of pro-test, yet urgent necessity compels someaction, and the good of the many shouldbe the controlling factor. The answer isthat incinerating plants finally are locatedsomewhere, just as radio transmitters finda place in the sun, at whatever spot.

Many DisgruntledThere must ever be the disgruntled, as

it is not pleasant to endure either annoy-ance-aerial or incinerator. In the muni-cipal problem, the only solution may befor the individual to move, but in regardto the radio question, this certainly wouldbe absurd, as the sufferers live in high-class residential districts, and residenceis more important than radio. Hence thequestion: What's to be done?



stall a wave trap. This consists of a vari-able condenser connected across a coil.The aerial is introduced at one end ofanother and smaller winding, while theend of the winding goes to the antennapost of the set. By setting the condenserso that the trap circuit is tuned to thewave of the interferer, this wave is ab-sorbed by the trap, and the actual receiv-ing circuit is left free to bring in otherstations, without crosstalk from theneighboring one. This is beautiful theory,but where the station is using 50,000watts, or even 1,500 watts, anything likeproximity makes it next to impossibletrap out the interference in this manner.The best that can be expected undermost of the adverse conditions is thatthe volume of the interference will declineconsiderably, which it is bound to do, andperhaps other stations may be heard with-out audible interference, while they aresending, even though a moment's silencefrom that source might enable one tohear the undertone of the interferer.Such a solution should be satisfactoryenough, indeed it is no more than mostof the complainants ask, but one mustlive perhaps a mile or so from the station.


wave trap, but used in conjunction withan extra tube, and with a variometer inthe plate circuit, will give very much bet-ter results. This is known as the RiderWave Trap and was described in theDecember 26 issue of RADIO WORLD. It isin reality a 1 -tube regenerative set, usedas a wave trap, hence a regulation setmay be employed by those who do notcare to build their own, e.g., a CrosleyPup. As the Radio Corporation ofAmerica owns WJZ and also is a licenseeunder the regenerative patent, it is sur-prising that the corporation does notmarket such a regenerative trap, and stopthe appeals and trips to Washington.




April 17, 1926 RADIO W ORLI-) 21


No Fear of a Monopoly,Says Free, Citing Sales



"In my judgment we already have suffi-cient governmental machinery to preventmanufacturing monopoly. The FederalTrade Commission and the courts canstop any monopoly under the laws al,ready in existence, and the InterstateCommerce Coinmission has full jurisdic-tion in the matter of rates.



"There are many very dependable radiosets on the market today in addition tothose made by the Radio Corporation,such as the sets made by the CrosleyRadio 'Corporation, the Atwater KentManufacturing Co., A. H. Grebe & Co. Infact, the Radio Corporation is third inthe sale of sets.


(Concluded front page 20)RADIO WORLD. The Fenway, properlybuilt, tunes out WHN, New York, at apoint of reception right next door to thestation. Other well -constructed Super -Heterodynes will do the same, e.g., theRadiola line and the Victoreen, the lattera home -constructed receiver. But ofcourse WHN does not use 50,000 watts,indeed only a hundredth of that.



in a cheap and poorly built set of indiffer-ent design where one is so unfortunatelylocated, although quite a few fans besiegedealers with demands that sets that sellfor a few dollars do more in the directionof elimination than do the best receiverson the market or within the scope ofhome construction. Asking too much isa favorite pastime of a few, or perhapsof many. A prospective purchaser beginsby reciting his grievance against the of-fender and demanding that he be sold aset, say for $35, that will tune out locals,including the transmitter next door, andbring in DX. While fans may be par-doned this over -expectancy, dealers whOencourage them in the belief that anordinary set will meet these demandsdeserve censure. And indeed they get it-when the customer comes back withthe set I


Rates lea per word; Minimum, $1.00; Cashwith order

WELL-KNOWN FURNITURE INSTALMENTHOUSE DESIRES TO LEASE OUT ITS RADIODEPARTMENT; PERMANENT WINDOW DIS-PLAY AND AMPLE FLOOR SPACE; ONLYEXPERIENCED RETAIL RADIO MAN WILLBE CONSIDERED; NO BEGINNERS, RE-SPONSIBLE PARTY WITH PERSONALCREDIT RATING; CASH GUARANTEE WILLBE ESSENTIAL; VICTOR AGENCY IN.CLUDED. BOX 292, 228 WEST 42D. N. Y. C.


"In 1925 the Radio Corporation soldtubes direct to 40 different set manufac-tuiers-the total number of tubes sold tothem being 1,363,150, or nearly as manyas those sold by the Radio Corporationitself in connection with its own sets.Practically all the other manufacturerssold their sets without tubes but equippedwith standard sockets for the insertionof tubes by the purchasers.











wish to beautify their radio sets has nowbeen placed on the market. A strikingfeature is that they are knockdown andcan be easily and quickly put together byanyone without the aid of bolts, nails,screws or glue. At the same time thefinished product is strong and rigid. Thefinish is rich American walnut or mahog-any on Southern gum wood. The No. 6size is 36" high by 34" long, 141/2" wide.Panel sizes fit any set from 7x12" to7x30". Full information and pictures maybe had from Cleverly & Cross, 321 Broad-way, New York City. Mention RumWORLD.

THE Banes of readers of RADIO WORLDwho desire literature from radio Job-

bers and dealers are published in RADIOWORLD on request of the reader. Theblank below may be used. or post cardor letter will do instead.Trade Service Editor,RADIO WORLD,145 West 45th St.. N. Y. City.


City or townState .Are you a dealer?

If not, who IN your dealer?His NameHis Address

H. R. Mercadal, 315 U. S. Custom HouseNew Orleans, La.F. Wilhelm?, 5 Pine St., Boston. Mass.E. Nelson, Alexandria Bay, N. Y.Chas. A. Fisher, Selinsgrove, Pa. (Dealer).F. P. Scniers, 2854 Montgomery Road, Shaken

Heights, Cleveland, 0.RThe adio Shoppe, 1836 N. Bond St., Balti-more, Md. (Dealer).

C. A. Halsterd, 5716 Normal Boulevard, Chicago,(Dealer).

Donald Hiller, 6614 South Sacramento Ave.,Chicago, BL (Dealer).

A. Rarsch, 2177 Pacific St., Brooklyn, N. Y.William Smith, 58 Grant St., Akron, 0,M. J. Claypoole, Kittanning, Pa. (Dealer).C. H. Bradbrook, 116 N. Topping St., Kansas

City, Mo.J. A. Gronin, 1 Wilcox St., Worcester, Mass.Arthur McKelson,' Valley City, N. D.W. J. Lyons, 3824 Prytania St., New Orleans,











cash in the bank and on hand of $523,610.How many businesses can show a finerstatement than this? Many radio manu-facturers are in equally good condition.Why should the radio industry have moreknockers than any other?


77

- -

It A TY T AI nAT April 17, 1926

Homes Exhibit Compares Speakers

r

TED NELSON, co -director and an-nouncer, WMCA, New York City

is an expert on re-mote control, andsucceeded in some ofthe most difficulttasks undertaken inthis line anywhere inthe country. Every-thing has to work otftjust exactly on time,or Nelson's task is afizzle. By carrying amicrophone and standwith him as a pre-caution, and going inheavily for fast taxirides, he achievesthat synchrony of TED NELSONtime and place that (Harold Sotto Photo).makes him successful. Often he has towork 12 hours a day. On one occasionhe went without sleep for 36 hours. Andit was not a case of insomnia. He says:

"Employes who close down their desksand rush into their street coats promptlyat 5.30 P. M., no matter how much workremains to be done, should get a job asa radio installation supervisor on remotecontrol work."

IMO DIAMOND OF THE AIR BOOKLET withfull instructions to make the Diamond. with blueprint, Soc. Newsdealers and radio dealers canget supply from A mcricao Ni,,. Co. and Itsbranches. RADIO WORLD. 145 W. 45th SR,N. Y. C.

New Plug ControlsBoth Tone and Volume

THE volume control.AN adequate volume control is needed

now more than ever before. If therheostats are turned low, volume will bereduced, but perhaps at the expense ofclarity. If turned too low on the audioside, distortion results. Partially detuningthe receiver helps, but in this day of con-gested broadcasting, such a procedurewill usually result in interference betweenstations.

Several of the best radio receivers in-corporate a tone control on the panel.Now an accessory has just been marketedthat provides successful control of toneand volume and can be added to any re-ceiver by the simple expedient of sub-stituting it for the old loud speaker plug.It is called a Modulator Plug and ismanufactured by the Central Radio Lab-oratories of Milwaukee. The size is littlelarger than that of a standard phone plug.Inside the body of the plug is a non -inductive graphite type of variable resist-ance controlled by means 'of a small knobon the plug. When attached to the re-ceiver, it provides an additional tone con-trol that can be adjusted to give any de-gree of tone volume from a whisper rightup to maximum.

An outstanding advantage of this typeof control is the apparent reduction ofstatic interference. As volume is reducedby turning the knob, the signal to staticradio seems to increase, until a point isreached where the program can be en-joyed without either detuning the set orreducing the filament pressure below thetemperature needed for best reproduction.

Little Sleep, Much Speed,

THE AMPLIFYING control room, from which visitors to the Ideal HomesExhibition in Olympia, London, were supplied with musical and educationalentertainment and demonstration of speakers. Station 2L0 broadcast the specialprograms. These were caught by the receiver at the left and then amplified by

the apparatus at the right. (Kadel & Herbert).

Madison Square GardenStation Goes on the Air

Madison Square Garden's new stationWMSG was opened officially with a pro-gram of speeches and music. The stationoperates on a 212.6 -meter wavelength.Speakers at the inaugural included TexRickard, John Ringling and James A. Far-ley of the State Athletic Commission.

In tests conducted prior to the officialopening programs were picked up in Cali-fornia and Texas, accordingreceived at the studio.

Walter J. Neff is studio director andannouncer; J. Bernhart, manager, and E.W. Dannals, chief engineer of the new sta-tion. The station will devote itself pri-marily to broadcasting sporting events.

Ted Nelson's Easy Task Tuning Fork FrequencySteadied by New Device

WASHINGTONThe Electrical Division of the Bureau

of Standards reports that a new method,exceptionally accurate, has been developedto measure the frequency of tuning forks,used by broadcasting stations and others.

The old system of driving the tuningfork by the "make and break" methodhas been done away with, and an ar-rangement whereby a "continual drive"is substituted, which gives much greateraccuracy.

Prof. Hazeltine Patentsthe Sacred Angle of CoilsProf. Louis A. Hazeltine, inventor of

the Neutrodyne, has obtained patents onthe placement of coils at angles to preventinductive feed back and interplay of fields.The 57 degree Neutrodyne angle and theright angle are covered, in fact virtuallyall angles.

TWO STATIONS FOR INDIAWASHINGTON

The Indian Radio Telegraph Co. is plan-ning the construction of a 12 -kw. broad-casting station at Calcutta, according toa consular report 'to the Department ofCommerce. It is understood this is one oftwo stations to be built in India, theother to be at Bombay.

New Czech StationOpens on 513 Meters

WASHINGTONThe new broadcasting station at Stras-

nice-Prague was recently placed in oper-ation, states a report to the Departmentof Commerce from Commercial AttacheJ. F. Hodgson, Prague, Czecho-Slovakia.

The international station call of thenew station is OKP. It was erected byan American firm and uses a 513 meterwavelength. The power at the antennais 5 kw.

During the week following the officialopening of the new station lectures werebroadcasted for the purpose of stimulatingthe development of radio in this country.

The Ministry of Posts and Telegraphsannounced a broadcasting subscription feeof 15 Czechoslovak crowns (or 30 cents)per month, a considerable reduction. Thenumber of broadcasting subscribers inCzecho-Slovakia was estimated at 30,000.

His Best in 12 Years,Fan Says of 4 -Tuber

RESULTS EDITOR:

Can't we rename your latest circuit byEdgar Collin "The Efficiency Four?" Itsure is a whiz, knockout and-well, wordsfail me. You can count on me as one ofyour boosters for the circuit and yourmagazine. Neither can be beat that's all.The set (described in March 27 issue)pick stations off on all waves with greatefficiency and DX.

In my twelve years of radio this is thebest circuit I have been able to gethold of.

R. H. LUCAS,1217 Jackson Ave.,

Wichita, Kans.

Specialize on S -C 4Radio Mail Order House is putting out

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-mamApril 17, 1926 RADIO WORLD 23

Making a Cone Speaker

FIGS. 1, 2, 3, and 4.

By Herbert E. HaydenPhotographs by the author

BECAUSE of the nature of the ma-terial used, and the comparatively

larger surface vibrated, in order to pro-duce the best results, it is advisable to usea more powerful unit to drive a conethan is required for horn operation.

The first step necessary for the con-struction of a cone speaker will be to geta large sheet of thin parchment paper,large enough to cut two circles about 20"in diameter.

The actual size of the circle will beeighteen inches, and since the ordinarykitchen workshop does not have a com-pass large enough to make this di-mensional spread, a piece of string andtwo lead pencils are used, the string be-ing tied around one pencil, which acts asthe center point, and then 9" distant, theother pencil, which in this case is themarking pencil, is carried around, and the18" circle on the parchment made. Twosuch circles are made (Fig. 1). This willmake a finished product considerably un-der eighteen inches, but is must be re-membered also that we are to work withthe average loud speaker unit, which doesnot have the power and pep of the largecone speaker magnet.

Having cut the circles out, we next cut

FIG. S

FIG. 6.

FIG. 7.

out a little angle as shown in Fig 2, about2" at the circumference and running backto the apex at the center of the circle.

Next coat one side of the "cut out sec-tion" (Fig. 3), with some good grade ofglue (not paste). The two sides of thecircle are brought together and firmlyglued down (Fig. 4). This gives the coneshape. Allow to dry thoroughly.

Next prepare the speaker unit for op-eration in the new form, by soldering apiece of number 18 brass wire or copperif you can't get the wire about 6" long.Some diaphragms have a coating ofenamel to prevent rust. Scrape the sur-face slightly, down to the bright metal.Solder the wire, called the reed, to thediaphragm (Fig. 5).

Two little thin brass thimbles are nextprepared by cutting from sheet metal,much in the fashion of the parchmentcircles, and soldering them at the radiusjoints. These little brass "cones" will beused at the center or apex of the parch-ment cone, one outside and one inside,and will receive the end of the 6" reed.If your speaker unit is of the adjustabletype, so much the better. The inset (lowerleft) in Fig. 6 shows how the brass circlesappear on the cone when completed.

Now the other large parchment circle isprepared the same as the first, and isplaced and glued into position as shownin Fig. 7. A circle about 7" has been cutfrom this cone, and strengthened by awooden ring about 1" thick, which has alsobeen cut to fit, and also glued to theparchment. Across this ring a strip ofthin wood has been placed, being fast-ened to the ring by two suitable woodscrews. The purpose of this strip is toform a support foe the speaker unit andits extending wire, which passes througha hole in the stick directly under thespeaker, and continues to the apex of theparchment cone directly ahead, and issecured to the two little brass thimbles,by a drop of solder.

Figs. 8 and 9 show how a cone speakerunit looks when taken out of a standardspeaker. Notice the wire sticking up. InFig. 9 we see how this big unit is placedon .the wooden supporting ring. A bigunit of this type gives considerable power.

Since it is rather a difficult problem toproduce a suitable mount for the finishedspeaker, in order to place it on a table orother similar support, the easiest way,

FIGS. 8 and 9.

FIG. 10.

and popular at this time, is to hang iton the wall (Fig. 10). A 20 -foot exten-sion cord is used to connect it to the set.

The edges of the cone can be mademore pleasing in appearance by gluingon a thin narrow art ribbon or gold braid.

The foregoing accounts for everythingexcept the bushing (inset Fig. 6). Thisis a cylinder in Fig 6, but may be anysmall price of metal, with a 1/16" or TA"hole drilled through, and the piecesoldered to the small outside metal "cone."Through this the reed protrudes and issecured by a set screw in the bushing.

Not One New StationLicensed in Six Months

No new licenses having been grantedsince last September, the list of applicantsfor broadcasting privilege now numbers519. Those which have been received re-cently are:

Paul Thompson, Chester, Pa.; WeberLaboratories, Lancaster, Pa.; ReadingTimes, Reading, Pa.; Chamber of Com-merce, Anderson, S. C.; C. M. McClung &Co., Knoxville, Tenn.; Braid Electric Co.,Nashville, Tenn.; Piney Woods School,Piney Woods, Miss.; Burton SpringfieldCorp., Tulsa, Okla.; F. D. Kalama, Kalama,Wash. Harold Kants, Springfield, Ohio;and S. 'E. Missouri State Teachers College.


cf

Farmers Find ReceiversSave Them Much Money

Radio is changing the marketing meth-ods of entire groups of farmers, accordingto nation-wide survey recently concludedby the National Farm Radio Council.

Importance of radio in the marketingof farm products is illustrated in the Na-tional Farm Radio Council survey by re-ports from 43 states, more than 46 percent of the replies giving specific exam-ples of cash savings effected by the use ofradio. Practically every report indicatedthe importance and value to the farmer ofhaving market reports from 24 to 48 hoursearlier than they are obtainable throughany other medium.

Typical of hundreds of reports of thefarmer's use of radio in marketing is thisone from a farmer living near Keytesville,Missouri: "Radio reported hogs due todrop in two days. Shipped at once. Saved$150. In same week put off haying be-cause of storm warning. This preventedheavy loss of hay."

Made Extensive TallyIn conducting this nation-wide radio

survey the National Farm Radio Councilgathered and tabulated 44,550 individualexpressions. The survey was conductedby the National Farm Radio Council inco-operation with 15 farm publicationswith an aggregate circulation of 3,086,409;450 county agents ; 200 boys' and girls' clubleaders; 150 home demonstration agents;the National Grange; the American FarmBureau Federation; several hundred teach -

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or evening when farmers make the great-est use of their receiving sets.

"Ninety-five per cent of the farmer-radio owners," the survey shows, "think oftheir radios as a utility as well as anamusement device. They think of it as autility because it brings to them marketreports from 24 to 48 hours earlier thanobtainable in any other way. These en-able the farmer to market his produce tohis greatest advantage.

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saquipmumpassistes,April 17, 1926 \\ O It I I, 25

and fruit territory, enables protectivemeasures which yearly save hundreds ofthousands of dollars.

"The farmer considers his radio receiveras a utility also because it enables hint tokeep in touch with his leaders, to heartheir talks on matters of current import-ance to the agricultural industry. Theradio is breaking down the isolation whichhas heretofore prevented farmers from in-terchanging ideas."

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Results of the survey to detvniumwhen the farmer listens in on his radioshows the maximum farm audience some-where between 8 and 8:30 in the evening.Starting at 6:30, the audience rapidlyincreases up to 8 o'clock. After 8:30there is a sharp decline. The size ofthe noon farm radio audience is one of theoutstanding results of the survey. A littlemore than W per cent of farm radio own-ers are on the air at 12 noon. In some

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.t.ites, notably Illinois, Kansas, Pennsyl-vania and New York, the noon audienceapproaches 75 per cent. Very few farmfolks, according to the survey, listen toradio programs before noon. There ispractically no farm afternoon audience. Asmall percentage of replies from farmwomen indicated some interest in house-hold talks and other home features,

Farmer Likes PunctualityWilli the facts established that radio

market reports mean dollars and cents toAmerican farmers, the Radio Council setabout finding out just when the farmerwanted his market reports. Tabulation ofmany thousands of replies left no doubt asto the time when market reports should goon the air. The farmer wants his marketreports at exactly 12 noon and exactly at7:30 in the evening.

Orchestra or band, educational talks,weather reports, market reports and sing-ing are the features with the greatestappeal to the farm audience. The orches-tra leads, with farm talks second. Weatherreports and market reports have about thesame general appeal. A wide decline ofinterest was registered regarding vocalefforts.

While the orchestra and band arc givenfirst place, a general objection by farmerswas made to jazz and there was a widedemand for more Hawaiian and old timemusic. Vocal selections were not popular.Male quartettes were preferred and so-prano voices found general disfavor.News bulletins were in general demand.

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LATEST LIST OF STATIONS appeared inRADIO WORLD dated March 13. I5c per ci-,Tor start sub. with that number. RADIO WORLI145 W. 45th St., N. Y. C.

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711WC112T.1) A nril 17 1 Q7A

Manners for ListenersDiscussed by Goldsmith

(Continued from page 12)

is hostile to complete absorption in a radioprogram.

Leaving the receiving set for the mo-ment, it is also important to see that theaudience is properly placed and in a re-ceptive mood. The audience should be infront of the loudspeaker and not too closeto it. All members of the audience shouldbe nearly at an equal distance from theloudspeaker. If any one is at a consider-able distance, he may not get the bestresults and may therefore lose interest andbecome a source of disturbance to theprogram. It is desirable to experiment inadvance as to the proper location of theaudience and to place chairs for a "radioevening" so that the audience will not onlybe comfortable. but properly located rela-tive to the loudspeaker. In other words, itis useless to expect artistic and satisfac-tory results unless one takes some trouble,which is a fact long since discovered bythose who have brought the theatre andconcert hall to their present advancedstage.

A few words of kindly advice to radioaudiences may also be helpful in this con-nection. Radio audiences would do wellto avoid just those acts and mental atti-tudes which would ruin their enjoymentunder similar conditions during a theatricalperformance. Imagine what would happenin a theatre if the audience, instead of be-ing properly seated in full view of thestage and where they could hear every-thing easily, were located in remote corri-dors where they could see little and hearonly an occasional garbled play extract.

Everybody knows that an audiencewhich was uninterested in a play from its

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very beginning would generally be hardto please and unlikely to become enthusi-astic. It is well to ask a radio audience,before beginning a program, whether theyreally want to hear it and to be governed

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by the majority decision. In fact, some-thing better than a majority decision (andalmost a unanimous decision) is a requis-ite justification for starting a radio pro-gram. Certainly more than half of theaverage theatrical audience is convincedthat it wants to see the performance, andthe same rule should govern radio per-formances.

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April 17, 1926

Ilsaippasimssampaana

R A I) I 0 () R I, I) 27

by the audience. Musical democracy isa fine thing in connection with radio per-formances. The user of a radio set whoforces his particular preferences on theaudiences is making a great mistake. Ofcourse, it may sometimes be necessaryfrankly to tell the audience that a certainprogram which they desire cannot be satis-factorily reproduced that evening becauseof interference or otherwise, but if it isavailable with satisfactory quality and theaudience desires it, it should be given tothem.

There is a reciprocal obligation uponthe audience, once the performance hastarted, to listen quietly unless the qualityof the performance deteriorates to thepoint where they no loncer eniov it.

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would be impossible to conduct a theatricalenterprise if the audience consistentlyshuffled their feet, talked across the aisles,and generally broke up the stage perform-ance. If the radio audience does not seemto pay attention to the program, it is al-ways advisable frankly to ask them if theystill want to hear any more of the per-formance. There is no use forcing a pro-gram on an unreceptive group. However,radio audiences have been somewhat re-miss in the past in that they have notgiven really superb programs anythinglike the same respectful attention whichthey would accord to an equivalent per-formance in a theatre or concert hall. One

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is sometimes tempted to wish that everymember of a radio audience had to payseveral dollars for his seat during the pro-gram and that a husky usher was stand-ing near him ready to take decisive mea-sures in case of continued interruption ofthe program. There is an obligation uponthe audience as well as upon the transmit-ting station, and the dignity and value ofradio broadcasting will never be fully real-ized until cooperation exists between radioaudiences and broadcasting stations, aswell as in the reverse direction.

It is fortunately true that if one has anexcellent receiving set, carefully installedand manipulated, and a receptive audience,one does achieve not only acoustic syn-chronizing, but also an artistic triumph.Radio is capable of giving these benefitsto its niyriad listeners.

In concluding this series of articles, itmay be added that, in common with theother engineers working to provide theimproved physical agencies for the listen-er's enjoyment of the best broadcast musicand speech, the author extends to thelisteners his wishes for the best of radioluck. And the object of this series on"Radio Music In The Home" has been tomake good luck in radio less a matter ofchance and more a matter of planning andcertainty.

A MAN-SIZED JOBWhat a task faces the program man-

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End Copyright ChaosIs Broadcasters' Plea

By Paul B. KlughExecutive Chairman, National Association

of BroadcastersWhen broadcasters started to use copy-

right musk, none of them had any ideaof its ramifications. In those days broad-casters considered themselves in the lightof public benefactors, as they were allrendering a public service with no visiblemeans of income. It seemed impossibleto collect from the listeners, and moneyfor the upkeep of stations was hard tofind.

At this particular period the AmericanSociety of Authors,'Composers and Pub-lishers came down so heavy for licensefees, and there is little wonder that broad-casters rebelled.

Now that at least 70 per cent of theregular broadcasters of the country arecharging for the use of their facilities byadvertisers, and now that a part solutionof the troublesome matter of income hasbeen developed, broadcasters have cometo the conclusion that they should pay forthe use of copyrighted music.

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Send us your broken andburned out tubes by parcelpost. (Not necessary to In-sure or guard against break-age.) We make return ship-ments by parcel poet C.O.D.and try to maintain 14 -hourservice.

HARVARD RADIOLABORATORIES

200 Old Colony AvenueSouth Boston, Mass.

by the American Society, through its pool-ing arrangement with copyright owners.A broadcasting station cannot successfullyoperate without the music of this Society.It is as necessary as raw material to themanufacturer. Supposing a furnituremanufacturer finds that 90 per cent, ofhis raw material consists of lumber, andten per cent of casters, hinges, hardwareand mirrors. Then supposing he findsthat his lumber is controlled by an organ-ization who pool their interests and chargewhat their fancy dictates. Would that bea sound position for the furniture manu-

FANS! NEW

All

SINGLE CONTROL RECEIVERas designed by McMurdo Silver and L. M.Cockaday; Described in March Issue of Popu-lar Radio. Wave Lengths Range from 50to 1800 Meters.

RADIO MAIL ORDER HOUSEP. 0. Box 129, Times Square Station, N. Y. C.

DISTANCE AND VOLUMEAt Your Command

Build a S -Tube Tuned Ra-die -Frequency Set, Usingthe Streamline Kit .50

Boxed Kit consists of 3 Streamline straightline frequency .00035 mid. condensers, 3basketweave coils, 3 mountings.

STREAMLINE STRAIGHTFREQUENCY CONDENSERS

.00025 mfd 52.00; .00035 mfd. 52.25;.00005 mfd. $2.50.

,r".....sr A 1!aV.I.gte rf rAn f'"677a iriKauviadial EVkt1/111.11223 F IJ LEON STREET

)..1)(ew York C.19,

QUICK ACTION CLASSIFIED ADS10 CENTS A WORD. 10 WORDS MINIMUM. CASH WITH ORDER

MERSHON ELECTROLYTIC CONDENSERSabsolutely filter out sixty cycle hums in eli-minators. Cannot burn out; last a lifetime; stand450 volts. Special price three dollars each ontwenty mfd. size in metal can. C. J. Brown. 52Vanderbilt Ave., New York City.

SHORT WAVE COUPLERS. 40-200 meters.$2.75. Martien Radio Shop, Galion, Ohio.

SILVER -GILT. THE NEW SILVER-PLATEDbus wire. Price 4c foot, postpaid. Also silver-plated antenna wire. Send for circular. J. A.Armstrong, 124 Pleasant St., Attleboro, Mass.

SELL MARVELOUS NEW RADIO INVEN-TION THAT IMPROVES summer reception 100%.Effarsee marvel inside antennae gives better tone,greater selectivity, less static. Sells to everyradio owner for only $4.00. Write today. Fish -wick Radio Co., 137 Central Parkway West, Cin-cinnati, Ohio. '

A PAYING POSITION OPEN to representa-tives of character., Take orders shoes. hosierydirect to wearer. Good income. Permanent.Write now. Tanners Shoe Mfg. Co., 4,710 C. St..Boston, Mass.

CASH PAID FOR DENTAL GOLD, falseteeth, discarded jewelry, diamonds, platinum.Mail. Florida Gold Refining Ca, 21 Adams,Jacksonville, Fla.

BULLDOGSBEAUTIFUL REGISTERED BULL PUPS. $15.

Bulldogs, 501 Rockwood, Dallas, Texas.

WANTED-DEALERS AND STATE DISTRIB-UTORS. Exclusive territory. Noiseless RadioBattery- Eliminator. Tremendous sales. Enormousrepeats. Large profits. Write. Harcurt Electric,2029 Indiana Ave., Chicago.

CONSTRUCTION OF RADIO PHONE ANDTELEGRAPH RECEIVERS by M. B. Sleeper,sent on receipt of 75c. The Columbia Print. 145W. 45th St.. N. Y. C.

DESIGN DATA FOR RADIO TRANSMIT-TERS AND RECEIVERS by M. B. Sleeper, senton receipt of 75c. The Columbia Print, 145 W.45th St., N. Y. C.

WIRELESS IN THE HOME by Lee deForest,sent on receipt of 15c.. The Columbia Print 145 W.45th St., N. Y. C.

1925 BACK NUMBERS OF RADIO WORLD WANTEDMail us copies of any of the following 1925 Issues of RADIO WORLD, and we will send you copy of a current issue for every copy sent us: January 10, February 21, March 21, 28, Apra 4,11, 25; May 16, 23, 30; June 6, 13, 20; July 4, II, 18, 25; Aug. 8, 15, 29; Sept. 5, 26; also Jan. 23. 1926.

Good Back Numbers of

RADIO WORLDThe following illustrated articles have ap-peared in recent issues of RADIO WORLD:1025:

Sept. 12-The 1928 Model Diamond of the Ale.(Part (1), by Herman Bernard. A 25 -to -110Meter Receiver, by Sidney E Finkelstein.Sept. 19-Diamond of the Air (Part 2). by Her-man Bernard. A Tube B Battery Eliminator.

by Louis Winner.Sept. 28-Diamond of the Air (Part 3), byHerman Remand. The 5 -Tubs Browning-Prake, by Capt. P. V. O'Rourke.Oat. 3-The Tbordarton-Wade Set (Part 1), byHerman Bernard.

Oct. 10-The 3 -Tube, 3 -Circuit Tuner. by Capt.P. V. O'Rourke. The Thordarton-Wade Set(Part 2), by Herman Bernard.Oct. I7-The Thoroughbred (1 -Tube DX Set),

by Herbert Hayden. The Thordarson-WadeSet (Part 3), by Herman Bernard. TroubleShooting Article.

Oct. 24-A Phonograph Cabinet Set by LewisWinner. The Thoroughbred, by Herbert Hay-den (Part 2).Nov. 7-A 8 -Tube Dry -Cell Circuit, by Capt.P. V, O'Rourke. One of the Beet CrystalSeta, by Herbert H Hayden. 1 -Tube DXSet, Herman Bernard.Nov, 21-A DX Super -Heterodyne. by J. E.Anderson. A 4 -Tube A -A Receiver, by Her-

bert E. Hayden.Dee. 5-A Tbrold BF Set, Using Crystal. byLewis Winner. The Diamond of the Air(in Text and Diagram), by Herman Bernard.Dee. 12-A Self -Contained Receiver, by H. El

Hayden (Port 1). B Battery Eliminator, byLewis Winner (Holiday Gifts No.).

Dee. IS-The Lonnie Entertainer, by Ed.Spies)°, Feldman 5 -Tube net, by Lewis W.Feldman.

Dec. 26-The Regenerative Wave Trap, by JohnF. Eider. The 5 -Tuba Tuned BF Set, byCapt. P. V. O'Rourke.

1926:

Jan. 2-The 2-C Set for SimPlielt.e, by CaPt.P. V. O'Rourke.

Jan. 9-1he 4 -Tube DX Symphony Set, by A.Irving Wits. A Skillfully Made 1.1311 Set,by Herman Bernard.

Jan. 16-Anderson'a 5 -Tube Quality Receiver,The Raytheon B. Eliminator, by Lewis Win-ner.

Jan. 23-The 4 -Tube Diamond of the Air, byHerman Bernard. The Antennatrol, by Her-bert E. Hayden (Part 1). B Batteries LastPis Months, by S. E. Finkelstein.

Jan. 30-An Individual AF Amplifier. by H. H.Hayden. The Antennatrol, by Herbert Hay-den (Part 2). Trapping Out Super -Powerin New Jersey. by Capt. P. V. O'Rourke.

Feb. 6-The Fenway (4 or 9 tubes), by Leo Fen -way (Part 1). The Great 1 -Tube DX Set,by Herman Bernard.

Feb. I3-Anderson's 15 -Tube Economical Receiver,Trouble Shooting for Novices, by M. B.Struck. The Fenway, by Leo Fenway(Part 2).

Feb. 20-The 8 -Tube Victoreen, by Herbert H.Hayden. The Fenway. by Leo Fenway(Part 3). Quality Stressed in 3 -Tube Set,by Brainard Foote.

Feb. 27-The 4 -tube DX Dandy, by Herbert E.Hayden. Umbrella Aerial for DX, by HugoGernsback. Part 2 of The Victoreen.

Mar. 6-The 1 -tube Set, by Capt. 0.11hurke. TheChemistry of Batteries, by A. IL Reid. TheVictoreen Bet (Part 3), by Herbert H. Hay-den.

Mar. I3-The Non -Regenerative Browning -DrakeSet, by If. B, Sleeper. The Teetron Elimi-nator (Part 1). by Lewis Winner. CuringVictoreen Trouble, by Herbert E. Hayden.

Mar. 20-The Super -Heterodyne. by I. E. Ander-son. A 2 -Tube Speaker Set. by Percy War-ren. The Browning -Drake Set (Part 2), byM. B. Sleeper. A 2 -tube Eliminator. byLewis Winner.

Mar. 27-An Economical 4 -Tube Set. by EdgarT. Collins. A Practical 11 Battery, by Capt.P. V. O'Rourke. Tectron Trouble Shooting,by Lewis Winner.

April 3-The Bernard Portable. by HermanBernard (Port 1). How to Get Dr, byCapt. P. O'Rourke. A Compact B Supply.by Lewis Winner.

April 10-The Bernard Portable, by HermanBernard (Port 21. Two Eliminators for DC.by Lewis Winner. A Super From An OldSot. by C. Mug.

Any cony, I5e. Any 7 miles, $1.04. Allthese 28 moles tor 64.06 or start subscriptionwith any Issue. RADIO WORLD, 145 W. 45thSt., N. V. C.

April 17, 1926 IZ A Ill 0 NV R I. I) 29

00 1FREE Ns0e

IF YOUR INVENTION is new and usefulit is patentable. Send me your sketch.7 H. POLACHEK, 70 Wall St., New York

Reg. Patent Attorney -Engineer

DON'T USE "B" BATTERIESA remarkable device just perfected.Easily built by any radio fan.Plugs into common light socket, uses no acids

or tubes.Delivers powerful, absolutely noiseless "B"

supply. Fully guaranteed.Complete drawings and instructrons $1.00

RADIO EQUIPMENT CO.10.11 W. 11th Avenue Mitchell. S. D.

210,000 SATISFIED OWNERS-Getting stations 600 miles away on LambertRadios. No batteries or tubes required. A realRadio-not a toy or attachment. One to four canlisten at once. If your dealer doesn't carry Lam-bert Radios, write us for literature-

LEON LAMBERT RADIO CO.Kaufman Building Wichita, KansasLiberal Offer to Dealers-Write Us Today

2254 voltrechargeable

"B"StorageBattery

$2.95Includeschemical

45 rolls. 55.25; 90 vita, 510 00; 112% volts.112.50: 135 rotten $14.75; 1571/4 snits. $18.80.Truly. the biggest buy today. Easily charged on In,Torrent. Including 32 -volt systems. Any special de-teetor plate voltage had. Tested and shivered byleading authorities such as Popular Radio Labor-atories. Over 3 year, sold on s n -red tape. 30 -daytrial offer with complete refundno It not thorough],satisfied. Further guaranteed 2 years Knock -dormkits at great savings. Complete "Burley. "B" bat-tery charger, 12.75. Sample cell. 35e. Order direct-send no money-simple Pay the eabressrnan cost

co delivery, Or write for my free literature, testi-monials and guarantee. Same day shipments. B.Hawley Smith. 318 washleston Ave.. Danbury. Cern.

facturer? Broadcasters arc in no differentposition with respect to music.

If broadcasters wanted to obtain musicwithout payment, or at it low payment,then there would be some basis for the op-position which conies from the AmericanSociety. \Ve cannot, however, discoverone valid argument which can be advancedagainst a proposal to pay fairly and lib-erally for the use of copyrighted music toevery copyright owner, whenever copy-righted music is used, whether he be amember of the American Society or not.\Ve have no desire to obtain this musicupon a low basis, but on the contrary arcwilling to pay fully and fairly for its use.1Vhat we do desire is permanency, so thata broadcaster may know whether he willbe, in business next year or the year after.

Condition Called ChaosFurthermore, any arrangement made

with the American Society does not takeinto consideration those writers outside ofthe American Society, who often are more

LOUD SPEAKER RECEPTIONfrom either coast on three tubes

Blueprint and instructions 51.61Necessary low leas coil 2.511Beautiful finished instrument 15.60

S. A. TWITCHELL CO1930 Western Avenue Alinneapolls, Minn.

iASTERPIECEAT AUTHORIZED

FRESHMAN DEALERS ONLY

GEM TUBEA Guaranteed Radio Tube

Within Reach of AllEvery tube guaranteed.A tube for a dollar of 12value. A trial order willconvince you es it hasthousands of others.Send your orders at once.Orders sent C.O.D.Parcel post.Type 200Type 201-AType 199Type199-A withStandard Base EachDealers, Write for Duicounts

GEM TUBE CO.Dept. W. 200 N. Y. G.220 So. State St., Chicago, Ill.Lafayette Bldg., Detroit, Mith.

00

TWO -FOR -ONE SUBSCRIPTION OFFERWorld has made arrangements

-To offer a year's erubsm-iption FREE for easyyear's subsca-iptloo for RADIO WORLD,-POPULAR RADIO or-RADIO BROADCAST or-SCIENCE AND INVENTION or

-RADIO NEWS-RADIO DEALER orThis is the way to get wo publications-for the price of met-Send 0.00 today for RADIO WORLD-for one year (regular price-for 52 numbers)-and sel,ct any we of the other-nine publications for twelve month...

one el the following pubkketion

-RADIO (San Francisco)-RADIO AGE or-COLLIER'S or-BOYS' LIFE or

Or

-Add MN a year extra for-Canadian or Foreign Portage.-Present RADIO WORLD subscriber.-can take advar.tage of this offer by-extending subscription mile year-it they trend renewals NOW.

with es.

RA010 WORLD'S Special Two -For -Price -of -One SUBSCRIPTION BLANKRADIO WORLD. 145 West 45th St.. N. Y. City,Enclosed find 56.00, for which send me RADIO WORLD for twelve months (52 numbers), beginnips a and also, without additional cost, PopularRadio, or Radio Broadcast, Radio Net., or Scimee and Invention, or Radio Dealer, or Radio(San Francisco), Boys' Life, or Radio Journal, Collier's or Radio Age (or $10.00 for two yearlysubscriptions).

Indicate if renewal.Offer Good UntilMay 5, 1926.

Name

Street Address

City and State

in need of payments than the establishedmembers of the Society. Therefore, webelieve our proposal is fair from everystandpoint. Then there is the public in-terest to consider. As matters stand atpresent, the American Society with-draws musical numbers from their licensedusers at will. This was done in the casesof Rose Marie, Nanette, and others. Asfar as the public interest is concerned, itis made up of a desire to hear the musicit wants to hear. If the public knowsthat the broadcaster pays for the use ofhis music, then he sees no reason whycertain popular numbers should be with-drawn at the height of their popularity.

In 1909 a Copyright Law was passed. Itcontains a so-called mechanical paragraphcovering the use of copyright music bymechanical reproducers such as phono-graph records, player piano rolls andothers. If radio had been known at thattime, it would undoubtedly have been in-cluded, because radio is a mechanical re-production.

Broadcaster! are trying to have thismechanical pa-agraph enlarged so that itincludes radio \Ve have no interest inthe rate paid by phonograph record manu-facturers. All we wish is the principle ap-plied to radio, and a new rate set for theuse by radio, which may be as high asCongress or any other constituted auth-ority may, in its judgment, determine asbeing fair and equitable. The career ofradio has been one of chaos extending ina long line from the producer of suppliesof manufuacttiring down to the ultimatelistener. It is time that at least one por-tion of this chaos be removed, and that afair and just settlement be made of a

matter which has been acutely controver-sial ever since broadcasting started.

Price$4 00

II

Tone Puritywith

Meloformerdlitr.rt end

tranel.rner Si,.,, Ly installing )11.-L0r011111KR.its new audio amplification

In lour OA -in volume, tors

.0-I value And for re-.ILralftshowing Mslo-t over /FAA oVr

Robertson Davis Co.420 Orleans St.. Chicago

WHITEHALLLOW -LOSS

INSULATORSTested and Approvedby the Radio WorldUo you realize how much you lose of '01.USIE and DISTANCE by poor insulation?

Use the WHITEHALL. Always dry inwet or damp weather. Moulded from No. IPORCELAIN, each surface highly glazed,and prove to yourself how much the BESTinsulation means to your set.

NOTE THE DIFFERENCE in RECEP-TION, this is the teat.

Send 98c and we will mail you a set ofWHITEHALL INSULATORS (Two). If,after connecting them to your aerial youarc not satisfied with the result, mail themback and we will refund your money.

WHITEHALL INSULATORSShi. ing De t., 4 Blount St., Whitehall, N.Y.

How to BuildTHE FENWA Y

The laws, DX art that, by the turn of aswitch, it a 4 -tabs tuned RF Jet, unthregenerators, or a 9drsbe Super -Hetero-dyne/ Remarkably senativelDescribed by Leo Fenvray himself In theFebruary S. 13, 211 and 27 Issues, Includingtrouble shooting. Send Sec for all four Is-sues, or send M for year's subscription andget these four copies FREE!RADIO WORLD, 14$ W. 45th St.. N. Y. C.


BST -6Range 180-550

B - for Beauty of CabinetS - for SelectivityT - for Tone purity6 - its 6 tubes for distance

Volume Control Perfect Calibration

The BST -6. 2 Feet 4 Inches Long. 9 Inches Inside Depth. 83/4 Inches High.

This marvelous six -tube tuned radio frequency receiver is Self -Equalized and built oflow -loss materials thruout. Its clear, rich tone of astonishing volume is a revelation.The circuit consists of two stages of tuned radio frequency, tube detector and threeStages of balanced audio amplification. Air cooled rheostats and universal socketsare used.Modified straight line frequency variable condensers are employed, insuring separation of thelow wave length stations. PERFECT CALIBRATION - STATIONS ONCE TUNED INCAN ALWAYS BE LOGGED AT THE SAME DIAL POINT.The balanced amplifier gives absolutely natural reproduction of all overtones. The universalsockets permit the use of all the popular tubes, either dry cell or storage. The set does notoscillate, thereby preventing the reradiation of signals and reducing interference to a minimum.

Direct from factory to you MOMNo dealers' or middlemen's profitsSPECIFICATIONS

Bakelite Panel, Walnut Finish-With Etch -O -Gravure and Gold Decorations-Bakelite Sub-Base--Kurz-Kasch Bakelite -Walnut Pointers; Gold-filled, to Match-Kurz-Kasch Bakelite Gold-filled Rheostat Knobs-Lubree Straight Line Frequency Condensers-Special Coils; Double Silk Solenoids-Shore Audio Transformers-Caswell-Runyan Two-tone Walnut -Finished Cabinet.

GUARANTEEEach receiver is tested and retested,boxed and inspected before leavingfactory, and guaranteed to reach youdirect in perfect condition.Workmanship thruout guaranteed thebest. Assembled by experts.

IMMEDIATE DELIVERY

Send Check or P. 0. Money Order to

Columbia Print, Dttn 143 West 45th St.,NEW YORK CITY

RADIO WORLD Guarantees the Responsibility of This Advertiser

April 1/, 1926 RADIO WORLD 31

BST -6 HIGHBOY"The joy of the hand that hews for beautyHas the sweetest solace beneath the sun"

A Radio Highboy ofunequaled value

The HIGHBOY is of genuine walnut -plywood de-signed by master craftsmen, beautifully finished in arich tw"-tone. Dimensions 451/4x251/4x141/4. A pieceof furniture that will last a lifetime, gladden the eyeand bring joy and refinement to the home.Equipped with the famous BST -6, a six -tube tunedradio frequency receiver of astonishing volume; ofclear, rich, beautiful tone, The circuit consists of twostages of tuned radio frequency, tube detector andthree steps of balanced audio.The concealed built-in loud speaker occupies the en-tire top of the HIGHBOY, overcoming entirely thattinny metallic sound of many of the old horn loudspeakers and in its stead giving forth that rich sym-pathetic tone of the old violin of long seasoned wood.Beneath the radio itself is the two -door compart-ment with ample room to fully conceal the A, B andC batteries.

Direct from factory to you

$85.00 Includes the BST -6Receiver Installed IPHighboy Period Cab-inet, as illustrated and

loud speaker.F.O.B. New York

GUARANTEEEach HIGHBOY is carefully examined so we knowthat the wood, carving, finish and trimmings are flawlessand in perfect condition. It is packed by experts in aseparate, specially -built, padded, wooden packing case,so that it must reach you in perfect condition.

The radio and loud -speaker are tested and inspectedfor workmanship, volume, tone and distance reception,so you will receive as nearly as is humanly possiblea perfect radio in this BST -6 Highboy.

IMMEDIATE DELIVERY

Send Check

See opposite page for detaileddescription of the BST -6 Re-ceiver as installed in this High-boy.

BST -6 Highboy

Height 45%", width 251/4", depth 10/4"

or P. 0. Money Order to

RaiColumbia Print,do

sion 143 West 45th St.NEW YORK CITY

RADIO WORLD Guarantees the Responsibility of This Advertiser

RADIO \VORLD April 17, 1926

Price, $1.50

Get the UtmostFrom Your Set!Use a Bretwood Variable Grid Leak !

WHEN you realize that thevoltage output of a set may

be increased 25 per cent. by cor-rect grid leak setting-when yourealize that regeneration and oscil-

lation control is finely achieved bythe variable grid leak-when you

realize that nobody knows in ad-vance just what is the correct

leakage for an individual detectortube-then you know that you

must use the Bretwood VariableGrid" Leak, else be content withless than maximum efficiency

from your set. More volume,greater distant reception, clearer

signals should be your goal.Bretwood is the solution. Adopt

it to -day!

The Bretwood Variable Grid Leak(Bretwood, Ltd, Sole Patentees and Owners)

Guaranteed Precision Range 1/4 to 10 Megohms

The Bretwood Variable Grid Leak Is OfficiallyPrescribed for the 1926 Model Diamond of the Air

The North American Bretwood Co.Telephone, BRYant 0559

145 W. 45th St., N. Y. CitySole Distributors for United States

North American Bretwood Co., 145 West 45th St.. N. Y. City.Gentlemen: Enclosed find $1.50. Send me at once one Bretwood Variable Grid Leak

on 5 -day money -back guarantee.

NAME

ADDRESS

CITY STATE

Inquiries Solicited from the Trade

Purchasers Are Delighted

With Results

I received the Bretwood Grid Leak.Thanks for your promptness. TheBretwood is the best grid leak that Ihave ever had. Since I placed it in my1926 Model Diamond of the Air Ihave received stations front nearlyevery part of the country. WMBF,WSB, KOA, 6KW,IVBAP, WIAX,WOC, KFKX, PWX, KGO and KFIwere all brought in on the speaker assoon as this instrument was put intothe receiver. As for clearing up dis-tortion, I have never seen anything toequal the Bretwood Grid Leak. Ihave placed one also across theprimary of the first audio -frequencytransformer and the results aremarvelous.

E. HIGGINS,130 Washington Ave..

Elizabeth, N. I.\ * *

An obligation of gratefulness impelsme to write you that any one who hasnot used the Bretwood does notknow, what a grid leak is.

BRUNO GONZALEZ.General Staff Sergeant.

Cu ban Artnv.P. 0. Box 910,Havana, Cuba.

* * *

I think the Bretwood is the bestgrid - leak I have ever used. Havemade quite a few sets and this beatsthem all. Get DX very plainly andclearly.

WM. HEBERSON,2510 N. Franklin St..

Philadelphia, Pa.* * *

Bretwood Grid Leak received andtested out. I find it is the only vari-able leak I ever used that is reallyvariable.

Enclosed find $1.50, for which pleasesend me another one.

F. E. STAYTONBox 240, Ardmore. Okla.

* * *

With your grid leak I was able tobring in with good volume 15 Wstations in one week with a Diamondof the Air set from a city hard toget out of.

Thanking you.F. W. COLLINGWOOD.

3442 Sacramento St..San Francisco. Cal.

*

I received the Bretwood VariableGrid Leak last night and it sure didbring in stations. Denver was as faras I could get until last night, when,with the Bretwood in my set, Ibrought in KFI, Los Angeles, andKPO, San Francisco, Cal., clear andfine.

10S. L. MARIE.4026 Grezella St..Pittsburgh. Pa.

Do YOU Want to Get Results LikeThese? If so, the Bretwood VariableGrid Leak is the Answer! Indorsedby Leading Radio Engineers andLaboratories. It Is the World's BestGrid Leak!

1

Documents

ILLUSTRATED Every Week A NEW METHOD OF POWER … · 2019. 7. 17. · liArttua 15 CENTS ol. 9. No. 4. ILLUSTRATED Every Week THE NEW 1 -DIAL 5 -TUBE POWERTONE SMOOTHING OUT CONTROL