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A 2 -TUBE SPEAKER SET

STUDY OF CHOKE COIL AF

DEFINITIONS FOR NOVICES

A SUPER -HETERODYNE DE LUXE

THE DE LUXE SUPER -HETERODYNE as seen from the rear. Dry -Cell tubes (99 type) areused, with a power tube (120) in the last stage, at left. A feature of this set is its expert layout.Regeneration is used in the antenna circuit, the midget condenser affording this. (Photo by Paul Hollingthead)

HOW TO MAKE PICKLE BOTTLE COILS150 to 200 Meters for Broadcasts, Senator Dill Proposes

INTIMATE ADVENTURES BEFORE THE MIKE

RADIO WORLD March 20, 1926

Price,

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-

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NAME

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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 if in my1926 Model Diamond of the 'Air Ihave received stations from nearlyevery part of the country. IVMBF,WSB, KOA, 4KW, WRAP, WJAX,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.

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RADIO WORLD[Entered as second-class matter, March. 1922, at the post office at New York. N. Y., under the Act of March 3, 1879.]

A Weekly Paper Published by Hennessy Radio Publications Corporation from PublicationOffice, 145 West 45th St., New York, N. Y. of Bro

Just war Phones: BRYant 0558 and 0559.adwa

Vol. VIII. No. 26. Whole No. 208. March 20, 1926 15c per copy, $6.00 a year

NOT all highclass radio re-

ceivers are built inlaboratories byskilled men whosevocation is radioengineering. N o tall high-class re-ceivers are built inaccordance with tIzeready - made planspublished in thevarious radio jour-nals, and laid outand described byprofessionals who are supposed to be wellversed ih the subject. A few superior re-ceivers are built by fans in their own homes

and in accordance with their own ideasand plans. One of the finest examples ofhome -constructed sets that the presentwriter has ever seen is the Super -Heterodynedescribed in this article, built by Paul Hol-lingshead, a photographer by vocation andan advanced radio experimenter by avoca-tion. Naturally, Mr. Hollingshead did notessay a complicated Super-Heterodyne thefirst thing. This receiver is his nth, where nis a large number not accurately known.He began by building the simpler sets 'wayback in pre-Neutrodyne days, then increas-ing the complexity as both he and the artdeveloped. He has used practically everygood receiver that has come out since hebegan as stepping stones to his presentstanding. -

Used His HeadIn building his various receivers he was

not satisfied by blindly running spaghetti -covered bus -bar between numbered terminals.He preferred to work from symbolic dia-grams of the receivers, and to use his ownjudgment about layouts and connections. Helearned the meaning of all the symbols,what the functions of all the componentparts in the circuit were, and to what de-gree the various parts available could beexpected to perform these functions. Hewas not satisfied with a finished receiverwhich would merely squawk. His sensitivemusical ear demanded quality comparablewith the original matter broadcast. Hischoice of parts from the aerial to the West-ern Electric conespeaker was made inanswer to this demand.

The present Super -Heterodyne representsMr. Hollingshead's own ideas as to whatconstitutes a good receiver, both as to physi-cal and electrical layouts; and it is the re-sult of careful study of all the Super -

A Super-HeterodyneDe Luxe

By J. E. AndersonConsulting Engineer

Heterodynes that have been published dur-ing the last two years. A scrutiny of thecircuit diagram will show that he is notalone in his opinion. The oscillator circuitis of the three winding type with one sideof the oscillator condenser grounded. Thistype of oscillator was selected because itwon out over the other types in actual trial.

Hand Capacity AbsentOne of its main advantages is that there

is, no hand capacity effect, since the rotorside of the condenser is grounded, or ofthe same potential as the hand that operatesthe dial. The modulator is the grid biastype, which many engineers regard as theonly logical type to use. Regeneration isemployed in the loop or antenna circuit asa means of varying the sensitivity; and thisregeneration is accomplished by the Hart-ley parallel feed method, with a midget con-denser for controlling the feed back. Theintermediate amplifier consists of threestages, iron -core transformer coupled; thedetector is of the grid condenser, grid leaktype, chosen because of its sensitivity, andthis is coupled to the last IF stage by anair core filter -transformer; the first stageof audio is transformer coupled, while thelast is auto -transformer coupled. Theantenna input transformer L112 is notan integral part of the assembled receiver,hut is external to it. Three binding pastsmerely are provided because the receiveris primarily intended for loop operation.The input transformer is used for longdistance reception and in cases where aloop would prove inconvenient. Thetwo windings LI. and 12 are wound ona piece of bakelite tubing 3" in diameterand have 10 and 43 turns, respectively,of No. 24 double silk covered wire. Thetap on the secondary is placed at the15th turn, measured from the plate endof the coil.

The two wind-ings L3 and L4 ofthe oscillator arewound on a pieceof Bakelite tubing2" in diameterwith No. 26 doublesilk covered wire,the tickler con-taining 45 turnsand the secondary60 turns. Thepick-up coil L5 iswound with 24turns of No. 26

double silk covered w're on 1.5" Bakelitetubing, and this coil is mounted on bearingsinside the larger tube near the tickler coilend. While the pick-up coil may be rotatedfor varying the amount of coupling betweenthe oscillator and the modulator circuit, nocontrol for this purpose is placed on thepanel.

Constants DiscussedThe two tuning condensers C2 and C4

are both of .0005 mfd. capacity of GeneralRadio make. The capacity of these con-densers and the inductance of the two wind-ings across which they are connected aresuch as to cover satisfactorily the broad-cast range of frequencies. The regenerationcontrol condenser C3 is a midget, while theby-pass condenser Cl is a .0025 mfd. San-garno Bakelite moulded condenser.

The first three intermediate frequencytransformers T1, T2, and 'T3 are GeneralRadio medium frequency iron core trans-formers, while the filter transformer T4 isof the same make, but in a tuned air corefilter. The condenser C5 across the second-ary of this transformer T4 is an integralpart of this filter, placedthere to tune thesecondary to a frequency of 30,000 cycles.When building this circuit, therefore, thiscondenser should not be considered. It ismerely included in the circuit drawing Fig. Ito indicate that it is actually there.

The 'grid leak in the detector is variable,and over wide limits. The grid condenserC6 is a .00025,mfd. Dubilier, and the by-pass condenser C7 in the plate circuit of thedetector is of the same size and make asCl.

The Audio ChannelBoth the audio frequency transformers

are Rauland Lyrics. The first, or T5, isused as a straight transformer, but thesecond, or T6, is used as an auto -trans-

/ s9,9

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An/zx c,,,..LAz jtZ2f,- ji IP/

0 - ' c, ,,i__\ 1

1 It,Go, ,C.

-C. KZ> 717

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THE CIRCUIT PATTERN of the 8 -tube dry -cell Super. Heterodyne in schematic form. The "first detector" uses the gridbias method, the "second detector" the grid leak-condensor method.

4 RADIO WORLD March 20, 1926

Assembly of the DX Set

MUCH OF THE WIRING is done under the subpanels, as this photograph by Mr.Hollingshead shows.

former. In connecting this transformer inthis manner, the terminal marked G is con-nected to the positive of the plate battery,the terminal marked P is connected to thegrid, and the two terminals marked B and Fare joined together and connected to thespring of jack J1 which leads to the plateof the first audio amplifier tube. This placesthe largest winding in the primary or platecircuit and both the windings connected inseries-aiding in the secondary or gridcircuit.

The blocking condenser C8 is a 1.0microfarad Dubilier. The grid leak R3 is a250,000 -ohm Daven, and the mounting forthis is aho of the same make. The by-passcondenser C9 across the B battery is of thesame size and make as C8.

All the tubes in the circuit with the ex-ception of the last arc Cunningham 299. Thelast is the UX120 power tube. All thesockets for the small tubes are Benjaminand the socket for the power tube is aGeneral Radio UX type.

Rheostat ControlA master rheostat R4 controls the fila-

ment current in all the tubes. A Westonvoltmeter V is put across the common fila-

ment line on the tube side of the rheostatand the voltage is always held at 3. Asa means of controlling amplification andoscillation in the intermediate frequency am-plifier, a secon-1 rheostat RI, in series withthe master rheostat, is connected in serieswith the first two IF amplifier tubes. Thisis an effective volume control and it doesnot seriously affect quality since it is usedfor the two tubes which are called on tohandle only small signal grid voltages. Withthis minor exception there is no tamperingwith the filament current in an effort totone down the volume in case it is too loud.Ample volume control is obtainable withthe pick-up coil and with the tickler con-denser C3.

Battery VoltagesThe plate potential on all but the two last

tubes is maintained at 45 volts with respectto the negative end of the filaments. On thefirst audio frequency amplifier tube the platevoltage is 90 volts, and on the last, or powertube, it is maintained at 135 volts. The gridpotentials on the various tubes are adjustedfor these plate potentials. On all the ampli-fier tubes and on the oscillator tube whichhave 45 volts on the plates the grid bias is1`., volts. On the modulator, or the second

Slipping of DialsConfuses Many Fans

PHOTO represents minimum settingof the condenser and zero setting of

the dial.

Much perturbance accompanies theseemingly inexplicable shifting of dialreadings. Sometmes a radioist enjoys thesimplified tuning attendant upt..n syn-chronously reading dials. Stations comein at 15-15, 20-20, 60-60, etc., if there areonly two dials, or if there are more, they

read similarly in step. This is hailed as anaccomplishment, as the stray capacitycoupling in the antenna circuit sometimesmakes the achievement of synchronyrather difficult. Then, as if for no reason,the whole scheme is upset!

This is often due simply to a loose set-screw on one or more of the dials. Especi-ally if the tuning condenser has end -stopsis there a tendency to jar the dial oneway or the other, therefore the dial set-tings, but not the actual condenser set-tings, are changed. The solution is to re-adjust the "off" dial, so that at zero or at100 it represents full capacity (dependingon whether the frequency or wavelengthsystem of tuning and dialling is used).Most fans, in either case, will prefer tohave minimum capacity represented byzero on the dial, and should test both dialsaccordingly.

LIST OF PARTSAn antenna input transformer, LI, L2 (or

a loop).An oscillating coil as described.Three General Radio medium frequency

transformers, iron core, type 271.One General Radio 20 -ohm rheostat, type

former, type 331.Two Rauland-Lyric audio frequency

transformersTwo General Radio tuning condensers,

.0005 mfd. each, type 247-F.One midget condenser.Two Marco vernier dials.Two Sangamo fixed condensers, .00025

mfd. each.Two Dubilier fixed condensers, 1.0 mfd.

each.One Dubilier fixed condenser, .00025 mfd.One General Radio 20 -ohm rheostat, type

214A.One General Radio 6 -ohm rheostat, type

301.One Variable grid leak.One Daven grid leak, 250,000 ohms, with

mounting.One double circuit jack.One single circuit filament control jack.One filament switch.One Weston filament voltmeter (panel

type 0-7, 0-140).Seven Benjamin sockets for UV199 tubes.One General Radio socket for UXI20 tube

(type 349).Seven 99 type tubes and one UX120 tube.

Accessories: Fourteen Eby bindingposts (C-, C-, C-, C-, C+, A+, A-,B-, B+ Det., B+ Amp., B+ Amp.; threeunmarked, for ant., ground loop); one22.5 volt grid battery, tapped for everycell; twelve No. 6 dry cells; three 45 -voltplate batteries, preferably large size; oneWestern Electric cone type speaker.

tube in the diagram, the grid bias is from3 to 6 volts. Various values between theselimits may be tried until the one is foundthat gives the best response. If two differ-ent values seem to give about equal volume,the greater negative value should be usedsince this is more economical with respectto plate battery drain. The tube operatingon 90 volts on the plate should have a gridbias of about 4.5 volts or slightly more.

The last tube, which has 135 volts on theplate, requires a bias of 22.5 volts or some-what less. The bias on the detector tube is,of course, positive, the grid return beingconnected to the positive end of the filament.The correct bias on the two last tubes maybe found experimentally by means of thevoltmeter. This is temporarily disconnectedfrom its present position and then connectedin series with the plate circuit of the tubefor which the grid bias is to be adjusted.

The jacks may be used for this purpose.The grid bias is adjusted until the pointeron the meter neither jumps up nor downwhen very strong signals are being received.When each of the two last tubes has beenadjusted in this manner, the voltmeter maybe returned to its permanent position. It is,of course, not necessary to remove the meterfrom the panel when the adjustment is made.

Speaker on One AudioThe first jack, J1, is mainly provided for

use with a headset, but it may be used formoderate volume on a loud speaker. J2 isthe regular output jack for loud speakeroperation. It is an automatic filament jackwhich leaves the filament of the last tubeopen when no plug is in the jack.

There are fourteen Eby insulated bind-ing posts altogether in the circuit. Threeof these are for the loop, five for the grid

March 20, 1926 RADIO WORLD 5

Panel View of Receiver

PANEL VIEW of the De Luxe Super -Heterodyne, as constru cted and photographed by J. E. Andersons personal friend,Paul Hollingshead. The 7x18" panel is of the frieze type. Photographed by Paul Hollingshead.

battery, two for the filament battery, andfour for the plate battery.

The master rheostat is of 6 ohms resist-ance and the other, RI, is of 20 ohms. Bothare of General Radio manufacture.

The filament power is supplied by a bat-tery of 12 No. 6 dry cells connected in series -parallel to give 4.5 volts. Since the totalfilament current flowing is about .54 amperewhen each tube is drawing normal current,each tube delivers about .137 ampere. Thisis near the rate at which dry cells deliverthe greatest number of ampere -hours, andhence this combination is the most economi-cal. The set may be operated on six of thecells connected in series -parallel, but thecurrent then in each cell would be slightlyexcessive.

The Builder's PhotographyThree photos, taken by the builder, are

shown herewith. One of these shows theattractive panel layout. It shows the fila-ment voltmeter at top center. Directlyunder this are the two rheostats, the masterrheostat at the right and the other at theleft. On either side of the voltmeter arethe two vernier dials which control the tint-ing, the oscillator being on the right and theloop at the left. The knob controlling theregeneration condenser is shown directly tothe left of the loop dial, and the filamentswitch S is directly under this knob. At theright end of the panel and symmetricallylocated with respect to the knob and switchare the two jacks. There is nothing super-fluous on the panel. Size of panel is 7x18"and material is hard rubber.

The second picture shows the interiorlayout of the receiver. The width of thebaseboard is 10", apd it is divided into twoparts, one of hard rubber and one of metal,both supported on metal brackets. Onecriticism may be offered to this arrangement,and that is the location of the oscillator coilwith respect to the metal part of the base-board. It is close to it and the field is atright angles to the metal sheet. Losses willbe introduced by eddy current induction. Thebuilder intends to replace this sheet of metalwith a strip of hard rubber; and any onebuilding the set should use insulating ma-terial throughout. Attention is called to thevery short leads from the transformersecondaries to the various grids.

The third picture shows the wiring under-neath the baseboard, together with the sup-

porting brackets and four o.f the five fixedcondensers in the circuit.

DX Not So Bad' A few of the DX stations picked up withreceiver from New York City follow:

loud speaker volume While most of the localstations in New York were on the air.

The photograph on the front covershows the so-called modulator tape atright, near panel, the oscillator at left ofthe coupler. The intermediate chain runsfrom right to left, the transformers in

Station Ant. Osc. foreiround being T1, T2, T3 and T4WSB, Atlanta, Ga. 62 62 65.5 (filter) in that order. The four C- postsWCBD, Zion, Ill 41 41 44.5 are in foreground at right, and readingKOA, Denver, Colo 36.5 36.5 39.5 thence to left are C+, A+, A, B-,KFKX, Hastings, Neb 29 29 32 B+ Det., B+ Amp., B+ Amp. The an-KNOX, St. Louis, Mo 28 28 31 tenna coupler is not shown, as it would beWCXB, Detroit, Mich 26.5 26.5 29.5 external to the set, if used at all. AKMOK, St. Louis, Mo 24.5 24.5 27.5 loop is inserted by placing its tips at theWENR, Chicago, Ill 24 24 27 two posts that connect to C2. As I2, ifWDBO, Winter Park, Fla 21 21 24 used, is grounded, the three posts are

All of these stations were received with for ant., grid. and modulator grid.

An Expert'sOf the Supe

[Part I of this article on "My Adventureswith Super -Heterodynes," by J. E. Ander-son, was published last week, issue of March13, when the illustrations, referred to in thisweek's text, were printed too. More datawill appear next week.]

CALIBRATED once for all, three con-trols present no hardship. It is even

possible to add two stages of radio fre-quency amplification and making this aregular Neutrodyne tuner. Some of theradio frequency tuned circuits may becombined so as to eliminate a control ortwo. If this is done it will be necessary toinclude a volume control in the radio fre-quency amplifier which is independent oftuning, otherwise the advantage of theradio frequency filter will be lost. Thiscontrol may be a rheostat in the filamentcircuits of the radio frequency tubes, butpreferably, it should be a voltage inputcontrol. All pick-up of signal by the os-cillator coil, the radio frequency coils, orleads must be carefully prevented byshielding. There should only be one ave-nue of ingress to the circuit, and thatshould be the loop or antenna. Theelectromotive force thus let in should becontrolled as to intensity so that no partof the circuit becomes overloaded.

Much of the squealing interference

Analysisr-Heterodyne

caused by radiating receivers has been at-tributed to regenerative sets in the pastwhile the Super -Heterodyne has beengiven a clean slate. That is not entirelyfair to owners of regenerative sets. It issafe to say that much of this type of in-terference during ,the international testswas caused by super -heterodynes. Manyowners of the more humble sets knew byprevious experience that they could notpick up trans -Atlantic stations, and,prob-ably did not try again. But owners ofSuper -Heterodynes thought they might,and they kept the oscillator dial whirlingall the time in the hope that they wouldhear something of a foreign origin. Andjust because they could not hear theirown squeals in the loud speaker theythought that no body else could. EverySuper -Heterodyne worthy of the namehas a good filter between the oscillatorand the loud speaker which effectivelyprevents squealing of this type from get-ting through. But rare is the Super -Het-erodyne which has any provision whichkeeps the radio wave generated by itsown oscillator from getting out intospace. Every Super -Heterodyne in oper-ation radiates. Some radiate much, somejust a little. Radiation of energy maytake place from. the battery and otherleads, from the oscillator coil, and from

(Continued on next page)


The Super -Heterodyne

aa

a

60 + 45 B - A

1-9°

ri____,,,,1-

iiii____,,,,,._ ___,.,.____,.,____,.,+

!,.1 ...__, H

CIRCUIT DIAGRAM OF THE PRESSLEY Super -Heterodyne. This uses the Autodyne system, where the frequency conver-sion is accomplished in one tube (combined oscillator -modulator). R is a balancing condenser. A tapped loop is necessary.(Q.) J. E. Anderson discusses radiation in conjunction with this receiver. A rheostat 41 is the oscillation control of the

medium frequency amplifier.

JO>

(Continued from preceding page)the antenna or loop. Even the Pressleycircuit, which is supposed not to be aradiator, does radiate. The radiation fromthe pick-up loop in a well balanced Press-ley may be infinitesimal but the radia-tion from the open field oscillator is cer-tainly not infinitesimal. A loop radiates ifradio frequency energy is fe.:1 into it, anda solenoid coil is nothing but a miniatureloop. Hence it radiates. No doubt theradiation from this circuit is very smallin comparison with that from certain otherforms of Super -Heterodyne, but it isthere.

In connection with overloading it maybe well to call attention to a phenomenonwhich is ofteei observed in a Super -Het-erodyne receiver. It sometimes happensthat on a loud signal this will entirelydisappear at that point of the dial whereit should come in loudest; that is, thesignal comes in weak at first as the os-cillator dial is turned, increases slowly,then suddenly disappears and remainsabsent for several degrees on the dial,then appears with the same strength as ithad when it disappeared, and then grad-ually disappears. This phenomenonsometimes also appears on the modulatortuning condenser and on the radio fre-quency condenser if there is one in thecircuit; and when there is, it is morelikely to happen. On these condensersthe silent space is usually much wider thanon the oscillator condenser. The reasonfor this silent space is obviously over-loadipg of some part oi the circuit, mostprobably either the modulator or the finaldetector. The remedy is to incorporate avolume or signal voltage intensity controlin the circuit; and this must, of course,be placed ahead of the overloaded part.The best places to put it are in the gridcircuit of the first radio frequency ampli-fier, the oscillator pick-up, and in thegrid circuit of the first intermediate fre-quency tube. It is well to have one suchcontrol in the grid circuit of the first tubein each of the three levels of frequency.

Overloading Explained

This overloading may be explained withthe aid of Fig. 1. AB represents a re-sonance curve of either the intermediatefrequency filter or of one of the radiofrequency tuned circuits. The ordinatesrepresent the volume, or signal voltageamplitude, and the abscissas representsthe frequency. Fl may he the frequency

, ,

the control is varied. It then increasesup to F2, where it is about as loud as itcan be received clearly. At this point itbecomes mushy and rapidly grows unin-telligible, until the overloaded tube chokesup and silence results. This silence isnoticeable for several divisions on the dialon either side of the setting which cor-responds to the resonant frequency Fr.At F3 the signal becomes clear again andremains so until it becomes so weak atF4 that it can no longer be heard. In a

well controlled set it should be clearestat Fr and it should not be heard at allat F2 and F3.

Intermediate OscillationIt often happens in poorly adjusted or

intentionally regenerative intermediatefrequency amplifiers that oscillation oc-curs in one or more of the tubes. If thisoscillation is feeble the set may be ab-normally sensitive as a result, but if it isintense it may completely ruin the set,unless the oscillation can be stopped bysome means. Oscillation in the mediumfrequency amplifier manifests itself inprofuse squealing as the oscillator dial ismoved. Beat squeals may be heard atevery' division, of the dial over the entirescale, and sometimes the squeals overlap.The intensity of these squeals varies fromthe lower limit of audibility to ear-split-ting howls. The squeals are due to beat-ing between the I.F. frequency and itsvarious harmonics as generated by thefrequency changer with the freqtzencygenerated in the oscillating I.F. tube andwith the harmonics of this frequency.The remedy for this kind of squealing issimply to stop oscillation in the,tube thatcauses the trouble. This may be done byshielding the various stages from eachother, by so placing the transformers asto minimize_ electro-magnetic and electro-static coupling, by neutralizing the I.F.stages as in a neutrodyne, and, in an ex-tremity, by reducing the .filament currentin the tube or tubes causing oscillation.This last method is bad practice, but isnevertheless the one most frequently re-sorted to.

How can radiation from a Super -Het-erodyne, or any other oscillating circuit,be minimized? One way is by shielding.It was stated above that this should bedone to prevent energy from coming intothe circuit by all avenues of ingress ex-cept one, the loop or antenna. If this -is done there is only one avenue ofegress; and it is easy to prevent theradio frequency energy from backing up

and escaping through that avenue. ThePressley method of balancing is one ef-fective way; neutralization of the radiofrequency amplifier stage, is another. Andif the locally generated oscillations cannotescape the circuit of course there will beno radiation. A receiver so 'adjusted canbe given a clean slate; the energy thatwould escape through any unbalance orthrough the sliielding is not likely tocause any interference. Another way ofminimizing radiation is by using closedfield ascillator coils, such as a static andtoroida! windings; and this method maybe used in conjunction with shielding.Next time the proud owner of a powerfulSuper -Heterodyne is interfered with whilefishing for distant stations let him first sethis own house in order before he givesvent to his feelings against the tickleraddict.

Blame for Harmonic InterferenceIn the Super -Heterodyne, and to a lesser

extent in other receivers, there is some-times considerable trouble from harmonicinterference. There is cross talk betweenthe second and even third, harmonic of along wave station and the fundamentalof a shorter wave station. For instance.WEAF, which is operating on a wave of492 meters, sometimes interferes with thefundamental wave of a station operatingon 246 meters; or WNYC, operating on526 meters, interferes in the same mannerwith WBPI, which is operating on 263meters. In the past this sort of inter-ference has naturally been blamed on thebig fellows, by accusing them of sendingout broad waves, or waves rich in har-monics. For a time I was "taken in" bythis accusation against the supposedly of-fending stations, but I have revised myopinion. I found that the receiver was toblame. The wave radiated by WEAF isquite free from harmonics, yet I have re-ceived that station with the set tuned to246 meters. A wave trap tuned to 492meters cut out the signal, but a traptuned to 246 had no appreciable effect onthe signal. This seemed to indicate thatthe harmonics arose in the receiver.

Harmonic TroubleFrequency doubling occurred in one or

more of the R. F. tubes, and the doublefrequency was selected and amplified.When the first tuner was set at 492 metersand the rest of the tuners at 246 meters,the signal was very loud, indicating thatin this case_ the first tube did most of thefrequency doubling.


A 2 -Tube Speaker SetBy Percy Warren

SFEARER volume on only two tubesmay be obtained from the reflex cir-

cuit shown in Fig. 1. The volume will befairly good on local stations. High ratioaudio -transformers may be used in bothstages.

It is advisable to use storage batterytubes, but if dry cell tubes are used theyshould be of the 99 type.

The radio -frequency transformers L1L2and L3L4 may be any commercial type,with tuning condensers Cl and C2 ofsuitable capacity, determined by the in-ductance of the secondaries. If the coilsare to be wound by the constructor, theymay be placed on 334" diameter tubing,3%" or 4" high. There would be twosuch forms. LI, the primary of the firsttransformer, would consist of 13 turns ofNo. 24 double cotton. covered wire. Thesecondary would be wound with the samekind of wire and would consist of 45 turnsif Cl is a .0005 mfd. variable condenser.If a .00035 mid. instrument is used, makethe number of turns on the secondary 58.

Crystal's Damping EffectThe crystal, because of its low resist-

ance, will have a damping effect upon thesecond tuned circuit, hence it will bepossible to utilize a greater transfer ofenergy than ordinarily. So L3, the prim-ary of the second coil, may consist of 16turns of wire. The secondary will havethe same number of turns as the othersecondary, depending on the capacity ofthe tuning condenser, as explained. Theseparation in each case between primaryand secondary is 5.".

The Circuit DescribedThe circuit consists of a stage of tuned

radio frequency amplification, a crystaldetector, a first stage of audio reflexedin the radio -frequency or first tube, anda second stage of audio, non-reflexed.The coupling media, in the audio channelare transformers. Fans having any athand may use those, and if the radiosdiffer it may be advisable to put thehigher radio in the first stage. This isAF1 in the schematic pattern.

Oscillation ControlThere is only one rheostat' shown. This

may be used to control excessive oscilla-tion in the reflexed tube. Strong oscil-lation on the lower waves, say on 350meters or less, is to be expected, due tothe comparatively large number of turnson the primary L3.

A rheostat may be used for the finaltube, also, but as this tube is not in acritical part of the circuit this resistormay be a ballast. If a 99 tube is usedhere, with a 4Y2 -volt A battery source (anordinary 'C battery), then the ballast mayhe a 4,Av-99 Amperite. If a ballast isused, put eswitch in series with the Aplus lead, not shown in the diagram, butif a rheostat replaces the ballast no switchwill be needed.

Theory of SetThe set is a reflex because the first tube,

designated by the numeral I in a circle,amplifies the signal both before and afterdetection. The radio wave enters the setthrough the antenna -ground system, LIbeing the medium therefor, and is trans-ferred to the secondary U, by mutual in-duction. In this secondary circuit it isafforded a path of lowered resistance byvirtue of the tuning of Cl and then ispassed on to the other secondary, L4,

Rellexed Tud.

O

A.1,

B.

C A , B

..-4t) A 4.

CIRCUIT PATTERN (Fig. 1) of a 2 -tube reflex receiver that affords fairly goodspeaker volume in the reception of local stations. The resistor in the filament legof the second tube is a ballast and its unconnected side should go to A minus. Aswitch in series with the A plus lead of the set and that post of the A batteryshould be included, if a ballast is used, but if a rheostat is substituted, omit the switch.

through the primary L3 of the interstagecoupler. LA is tuned likewise. Thecrystal is connected between the "highpotential" side of IA and the primary ofthe first audio -transformer, and- thusseparates the audio wave from the radiowave, rendering audibility possible. Theaction is called detection. The secondaryof AF1 picks up the alternating currentwhich the audio -transformer introducesand this is passed back to the first tubeby connecting the G post of the trans-former to the grid of that tube, throughthe coil U. In other words, the gridreturn of L2 is made through the audio -transformer secondary. To facilitate thepassage of the radio wave by-pass con-denser is sometimes advisable across theaudio:transformer secondary. This is C3in Fig. 1. It should not be of large capac-ity, to avoid passing audio current. Theplate of the first tube, at this stage, rep-resents audio output, although, as Wehave seen, it is handling radio frequenciestoo. The end of L3 is brought to the Ppost of the second audio -transformer, andthe B voltage is delivered through theprimary of AF2 to the plate of tube (1).The audio current, again amplified, is de-livered to the grid to filament circuit ofthe last tube, in the plate circuit of which,in series with the positive B, the speakerconnections are made through a jack.

Layout of SetThe set may be made on a 7x18" panel,

LIST OF PARTSTwo radio frequency transformers,

L1L2, L3L4.Two variable condensers, Cl, C2.One crystal detector.Two 4" dials.Two dial pointers.One 20 -ohm rheostat.One 99 4v-99 Amperite.One single -circuit jack, J.Two sockets.One fixed condenser, .00025 mfd., C3.Two audio frequency transformers,

AF1, AF2.One 7x18" panel.One 7x17" baseboard.Accessories: 100 ft. aerial wire, 50 ft.

No. 14 insulated leadin wire, window lead-in connector, ground clamp, lightning ar-restor, bus bar, battery cable (connectingsbeing made to most convention pointdirect on parts used); two 99 tubes; two45 -volt B batteries; two parallel connected44 -volt C batteries, used as A battery for99 tubes; one extra C battery, used as Cbattery, bias 41i -volts negative.

with plenty of room to spare. With panelin front of you, the coil L1L2 may be atthe rear left tear of a 7x17" baseboard,the reflexed tube being in front of thecoil. The other coil may be placed on thebaseboard, too, its nearest point .3" backof the panel rear, (unless the condenserC2 is deeper), and the coil at right anglesto the other coil, and about 7" away fromthe nearest point of L1L2. The first audiotransformer would be at the right-handfront side of the baseboard, while theother audio -transformer would be behindL3L4,. about 3" free space existing be-tween the RF and the AF transformersmentioned. The final tube would be tothe right of the second AF transformer.

The panel would show the two tuningdials, centers 4" from left and right of thepanel edges, respectively, with..6" in be-tween the two dial edges. The rheostatwould be under dial No. 1 and the switchunder dial No. 2, with the single circuitjack 9" from left and 134." up. Two dialpointers should be added, unless the dialsused are of the type that do not requirethem, such as the window model dials. -

The ReflexingThe actual reflexing is one of the prob-

lems, especially for a beginner, as he getsconfused. in the doubling up of the pur-poses. Therefore the wiring of the re -flexed stage will be stressed, in conjunc-tion with a sketch of the wiring work.

Be sure to connect the coils so that, ifthey are placed with primary consideredon top, the connections would be: aerialto top terminal of LI, ground to bottomof LI; top of U (point adjoining end ofLI) to G post of AF1, other terminal ofU to grid of tube (1). Beginning or topof L3 to plate, end to P post of AF2; be-ginning of IA, (point adjoining end of L3)to minus C; other terminal of IA to oneside of the crystal. The other side ofthe crystal goes to the P post of AF1.

The rotor plates of the variable con-densers go to the G post of AF1 and toC minus, respectively.

The fixed condenser C3 is placed acrossthe secondary of AFI. Note that the endof the primary of AF1 and the end ofthe secondary are connected together, thatis, both terminals go to ,C minus. Thisimparts no negative bias to the crystal,since the output side is not connected toA minus.

Note that in the diagram one side ofthe ballast is not connected. It goes to Aminus. Draw the line in there, hoppingover A plus on the way down.

NEWS DEALERS, ATTENTION! There is a big demand for RADIO WORLD'S "1926 Diamond of theAir" Booklet and Blue Print. Retails at 50 cents. You can get supply at wholesale rates from RADIO WORLDOffices or from the American News Company and Branches.


Choke Coil AmplificationSubstitution of Primary of Bell -ringing Transformer for

Regular Choke Coil Impairs Purity of Wave Form,Photographs and Tracings of Actual Wave Forms Show

PHOTOGRAPH of an audio -frequency wave, made from the fluorescent screen ofa cathode ray oscillograph tube. This shows a 60 -cycle note, the familiar line hum.

[This is the second of a series of articlesdescribing the results of making audiowaves visible by means of a cathode rayoscillograph. The electronic stream in thistube enables portrayal of audio wave formand amplitude on a ground glass at thetop of the tube. Thus the waves may bephotographed or traced. Last week's articlecompared the purity of crystal rectificationwith that of ordinary tube rectification, theauthor reporting no difference, except thatthe amplitude (voltage) was much greaterwhen the tube was used. This week thechoke coil audio amplifier is discussed.]

By John F. RiderMember, Institute of Radio Engineers

(Copy ri ght, 1925)

T is said that a little knowledge isdangerous. That statement is indeed

true, and nowhere is its accuracy so fre-quently and forcibly illustrated as whenthat proverb is applied to radio matters.Without attempting to assume the role ofa critic, it must be admitted that manyerroneous statements have been madeunder the guise of well -intended sugges-tions. The majority of these have beensuggestions of various substitutes to beused in place of the original. This isespecially true when the discussion per-tains to audio -frequency amplification

and the audio -frequency amplifier unit ofany one receiver. Particular reference isbeing made to choke coil audio -frequencyamplification.

The Rule in AmplifiersThe comparative degree of efficiency of

the choke coil amplifier and that of thetransformer and the resistance units areat this time beyond the point, and willnot be discussed. But the selection ofvarious chokes adaptable as the couplingmedia in this type of audio -amplifier isof greater interest. It has been frequentlydemonstrated in many fields and activitiesthat substitutes as a rule are not as goodas originals; if they were they would notbe classed as substitutes. And this issignificantly true in audio amplifyingunits of the impedance coupled type, asintense electrical design is necessary sothat the proper operation be obtained.This in fact is true with practically everyunit utilized in the radio receiver art.Hence one need not be an electrical ex-pert to comprehend the fact that byvirtue a the design factor, an electricalunit specifically designed for a definitefunction will not afford the maximumwhen applied to some other use.

Now with due respect to the well mean-ing individuals who recommend the use

of various types of bell ringing transform-ers, spark coils, etc., in place of the chokecoil designed for use with impedancecoupled audio amplifiers, it is highlyrecommended that the practice be stop-ped, since it is not conducive to the re-sults strived for. This fact was con-clusively determined by the writer in aseries of experiments conducted in anendeavor to ascertain just how effectivethese various substitutes were, when com-pared with chokes expressly designed forthe purpose. It might just as well bementioned at this stage that the sub-stitutes proved dismal failures, insofar asfaithful amplification of the input signalwas concerned.

Taste a Personal FactorNo doubt many fans will not agree with

the writer, these fans having at one timeor other utilized bell ringing transformersas chokes in impedance coupled amplifiers,and obtaining what were consider .f4 sat-isfactory results; or some are now usingthese units with perfect satisfaction tothemselves. But the question naturallyarises as to the individual's musical palateand the fidelity of amplification. Betweenthese two there is a great divergence.Some of us prefer high tones rather thanlow tones, the coloratura soprano beingmore popular than the basso. But in theselection of equipment to be used in anaudio amplifier, so the tone frequent,amplification will be as perfect as possible,especially when the system is recom-mended to others, personal likes and dis-likes become secondary. The item of im-portance becomes the faithful reproduc-tion of the signal that was passed into theamplifier. Consequently the equipmentused, irrespective of manufacture, shouldafford these results.

Now in view of this situation it ismighty difficult to suggest substitutes totake the place of specific units designedfor a certain function, especially whenthe test upon the substitute is conductedby means of the ear. That is, the ear isthe judge of the output tone entirely with-out knowledge of the input tone. This,in substance, is the reason for the state-ment that bell ringing transformers shouldnot be suggested as chokes in choke coilcoupled audio amplifiers.

One Element LackingThe difference between the input and

the output tones is not noted, simply be-cause the input is unknown, and if anyamount of amplification is obtained it isassumed that the tonal characteristicshave been retained. This will be clearedup by comparisons of the input wave formand the output wave form with varioustypes of bell ringing transformers usedas chokes, and compared against a regularchoke designed for that purpose.

The equipment utilized is a cathode rayoscillograph. The process of operation isto obtain a photograph of the originaloutput of the audio oscillator as fed intothe amplifier and then to again photo-graph the output wave form as obtainedfrom the amplifier. Any variation otherthan increased amplitude will immediatelybecome apparent, which variation in waveform will constitute a difference in tone,although this difference in tone does notsignify a difference in frequency, but

Isnantso


A Test of Audio Qualityrather a loss in the distinguishing char-acteristics. By distinguishing character-istics is meant the difference in tone ofmiddle C on a saxophone and middle Con a banjo.

Vocal DifferencesThis loss in distinguishing characteris-

tics with certain amplifying units is thereason that the broadcast voice may berecognized with one type of unit and notwith another. The former retains thesmall but important variations whereasthey are lost entirely in the latter.

The equipment utilized consists of fourdistinct units. They are, the cathode rayoscillograph itself; the time constant pro-ducing device, by means of which theimage upon the oscillograph screen canbe made stationary; the audio oscillatorand the audio amplifier. To give wiringdiagrams and explanations of the firsttwo units would require excessive space,but wiring diagrams of the audio oscil-lator and the audio amplifier are given inFigs. 1 and 2. The chokes tested were aThordarson, compared against a Dongan,a Viking, a Killark small, and Killarklarge. In each of the four bell ringingtransformers the primary was used, thatis, the coil was connected to the AC line,with the secondary left open. This is thearrangement usually recommended.

A 50 -Cycle Note Used

- To proceed, a note of approximately 50cycles was generated by means of theaudio oscillator and the image as shownon the oscillograph traced and reproducedas in Fig. 3. This low frequency wasselected as frequency spectrumis the cause of most discussion among theradio fraternity. It is said that resistanceand impedanceecoupling bring out the lownotes lost in regular transformer coupling,therefore the tests should really be -madeupon low frequencies. As an incidentalcomparison between the regular chokeand resistance coupling, the curves ofFig. 3 A and B are also given. Curve3 A is that for resistance and cruve 3. Bfor the Thordarson choke. These curvesare the amplified reproductions of theoriginal wave form shown in Fig. 3 afterbeing amplified by the audio amplifier.The constants for the amplifier unit werearranged so that the tube was operatingat best efficiency. Relative to the variancebetween the amplification characteristicsof the two methods, the general opinionis sustained, namely that resistance coup-ling is truer than choke coil coupling. Inthis paper, however, this fact is beyondthe point, but will be discussed in detailin a subsequent paper.

Effect of SubstitutionInserting the Viking bell ringing trans-

former in place of the Thordarson chokeand utilizing, as has been mentioned, theprimary of that transformer as the choke,everything else remaining constant, thewave form shown in Fig. 4 was obtained.In amplitude this wave was approximatelyone -sixth that of the Thordarson cholcoutput. A close examination of the waveform is not necessary to disclose the factthat it has undergone a change other thanin amplitude. Certain additional peaksand depressions have made their appear-ance, which cannot be found in the orig-inal input. An audible notation of the out-put by means of a loud speaker in placeof the oscillograph brings to light thischange by a different pitch to the outputsignal. Now, if the original input waveform were not available it would be per-fectly logical to assume that the waveform as obtained with the bell ringingtransformer as a choke is the correct one

To Ootillograph

To Ampline,

FIG I THE AUDIO OKILLATOR

FIG DA

and correspondingly the note as emittedby the loud speaker to be the correct one.A comparison between the input and theoutput however shows up the. discrepancy.

Continuing further, the Viking unit wasreplaced by a Killark, large size, and thecurve obtained is shown in Fig. _4 A. Thewave form amplitude was even smallerthan that obtained with the Viking, andthe distinguishing characteristic was againmaintained. In addition, the depressionsand slope marked D and S in Fig. 4 havebeen shifted somewhat. Replacing thelarge Killark unit with the smaller oneresults in the curve 4 B. The differencethis time is more in amplitude than inwave form, the smaller unit affording agreater output. Connecting the Vikingand the small Killark primaries in seriesresults in the curve shown in Fig. 4 C. Alarge increase in amplitude but the samedeficiency in wave form are present.

The MoralNow to show the detrimental effects to

a still greater degree a more complexwave form was obtained. This was theoutput of a rotary converter. The originalas obtained from a step-down transformerIs illustrated in Fig. 5. The output withthe Thordarson choke is shown in Fig.5 A. This is followed in Fig. 5 B and 5 Cby the output wave forms with the vari-ous bell ringing transformers. While theoutput of the Thordarson choke is not anabsolute amplified reproduction of the in-put, it is nevertheless a more nearly per-fect reproduction than either of thoseshown in Figs. 5 B and 5 C.

As to the moral, there is only one andit is very simple. Do not employ bellringing transformers as the couplingmedia in impedance coupled audio ampli-fiers. If you desire impedance couplinguse the chokes designed for that purpose.Insofar as the operation of these chokes

PIG 6

T

FIG. 2 THE AUDIO AMPLIFIER

tiFIG.15

is concerned upon frequencies abovethose used in the measurements, the samedeficiency will exist. And in addition, theaverage voice wave forms are even morecomplex than those shown herewith andthe output from the audio amplifier equip-ped with bell ringing transformers forchokes will be far removed from theactual input wave form, assuming perfectamplification and rectification precedingthe audio unit.

The bell ringing transformers mentionedherein function well when used for thepurpose intended, but do not employ themas impedance coupling units for the a -plification of the voice frequencies.

An Improvised Leak

A PIECE OF PAPER, dipped inIndia ink, makes a grid leak of un-known resistance and short life, but

handy in an emergency.

RESULTS EDITOR:I wish to add my congratulations to the

very many folks who have praised Her-man Bernard and his 1926 Model Diamondof the Air. 1 was located in the toughestspot for reception in New York City andprobably in the United States. WithWJZ, WJY, WHN, WGBS, WMCA andWHAP all going, I had no trouble inreceiving stations in Chicago, etc.-J. L.,Dunn, Kansas City, Mo.

FIG 111

RADIO WORLD March 20. 1926 1

The Pickle -

FIG. 1, take fairly stiff piece of card-board, mark off eight lines as shown.Fig. 2, take this marked strip andwith the edge of the ruler bend thecardboard so as to make an octagon -shaped tube. Fig. 3, this tube soformed is shown in this photo, beingheld together with adhesive tape.Place the tape on the inside of thecardboard, using two strips about 4"long. Fig, 4, before the actual wind-ing is started, cut two pieces of thetape, and fix them under the wire sothat the sticky side will be face up.The wire is then wound right over this.FIG. 5 shows the completed winding,with the two pieces of the tape foldedover, thereby holding the coil in shape.

By Herbert E. HaydenPhotographs by the Author

THE construction of a pickle -bottlecoil is shown in the accompanying

photographs. The diameter may be mea-sured when the cardboard is in circularfashion. before the octagonal separation is

ottle Coil

FIG. 6, the winding form is now tornapart and the finished coil removed

as shown.made, and the amount and kind of wire toput on will be the same as for the straightsolenoid. Winding directions were givenfor a variety of coils in the March 6 issue

of RADIO WORLD, and these may be fol-lowed. For a radio -frequency trans-former, if No. 24 single or double silkcovered wire is used, or even No. 24double cotton covered, the, wave bandwill be covered with a .0005 mfd. con-densers if the secondary has 45 turnson a 3" diameter. For straightline fre-quency condensers, however, the numberof turns on the secondary might well be50. The primary, separated %" from thesecondary, would consist in either case of10 turns of the same kind of wire as wasused on the secondary. For condensersof smaller capacity or of the same capac-ity, but with smaller diameters, moreturns would have to be used, and it isadvisable to consult last week's table toascertain the answers.

SCHNELL IN NEW POSTHARTFORD, CONN.

F. H. Schnell, traffic manager of theAmerican Radio Relay League since 1920,has resigned to go with the C. F. BurgessLaboratories at Madison, Wisconsin,where he will undertake experimentalradio development., ,How Best to utilize

Broadcast Time ,SignalsBy Capt. P. V. O'Rourke

Formerly Navigating Officer, U. S.Merchant Marine

y N determining exact tune, a vast con-vertience in all the affairs of everyday

life, radio has played an important part.In many large cities the dropping of a

ball on a high tower indicates exact noon.The error of the signal, only a fractionof a second, is published in the localnewspapers of the following day.

Correct time is established by astrono-mers at the Government Observatory atWashington, D. C., by observations of thefixed stars, the sun and other planets.

Method of RegulationClocks and watches are regulated to

run according to the average or "ficti-tious" sun,' which makes all the days ofequal length; the sun itself is sometimesahead of this "fictitious sun" and some-times behind it. This deviation is calledthe equation of time and varies from asecond to nearly seventeen minutes.

The mechanical equation causing time-pieces to gain or lose time makes it neces-sary to have some means of checkingthis error to insure uniform time forregulating our various affairs.

One of the first practical uses to whichradio was put was the sending of timesignals to ships at sea where time is

the most important factor in accuratelydetermining latitude and longitude andconducting a ship from port to port.

Makes Big DifferenceThe difference of one second equals one

quarter of a mile at certain positions onthe earth's surface.

The consequences due to an unknownerror in time at sea can be readily appre-ciated.

One day I was called upon by a radiofan to determine the possible cause of

a diurnal disturbance which blurred hisreception for about five minutes. It wasmore annoying than static, but disap-

peared suddenly without any apparenteffort on his part in manipulating the set.

Many Think It's "Trouble"Since then rve inquired among other

radio set owners and much to my surprisefound that he was not the only one havingthis "trouble."

There were some who admitted it gavethem some concern until they finallyheard the last line: "The next dash youwill hear will be exactly ten o'clock East-ern Standard Time."

The time signals as sent out by NAAat Arlington, Va., are not sent out onthe broadcasting wave band, but they areretransmitted by several broadcasting sta-tions throughout the country at 9:55P. M., Eastern Standard Time, and con-tinue until 10 P. M.

The ScheduleThe schedule is as follows: the first

dash at 9:55 P. M. and subsequent dashesat one second intervals for 28 seconds, the29th second silent and starting again onthe 30th second, continuing at one secondintervals until the 54th second and re-maining silent five seconds, resuming onthe 60th second or whole minute. Thedashes are repeated in this way until the49th second of the last minute, when thereis a'silence of ten seconds ; it is at thisperiod when the announcer cuts in withthe warning-that the next dash you willhear is the final signal.

You may find it necessary to depend onyour chronometer to catch a train orreach the bank or file an important docu-ment or for some other reason wherethe correct time is imperative hence it is.well worth knowing the rate of gain orloss of your timepiece.

This may be established by keeping arecord of your time daily for a weekor ten days and noting whether theamount of gain or loss is constant. Wherethe daily error is irregular compute thetotal number of seconds and divide bythe number of days recording, the answerbeing the average rate of gain or loss.

1


The KB -8[Part I of this article on the KB -8, a 5 -

tube non -regenerative set, was published lastweek, issue of March 13. The final instal-ment will appear in the March 27 issue. Thephotographs published this week are by cour-tesy of "Radio Engineering."1

PART IITHE pictures show the manner that

Lastites have been used for nearly allof the connections. When a screw is toolong to take a Lastite, put the screw inplace and fasten it with an ordinary o-32nut instead of the Lastite. Then cut thescrew off and remove the nut. That willleave the screw just long enough to gointo the Lastite. A Yi." Spintite wrenchmakes this work a great deal easier. Intwo or three cases it is necessary to cutthe head from a screw in order that oneend can go into a Lastite or coil mount-ing pillar, with a Lastite on the other end.

When the set is mounted in a cabinetit may be well to arrange a small woodenblock at the back of the -cabinet so asto support the two corners of the largetube panel. The construction is verysturdy, however, for three angle bracketshold the horizontal panel in place. Thevertical panel, in turn, is fastened to thefront panel by four heavy panel supportpillars.

Panel DataThe front panel measures 7x24"- The

original model was made with Celoron,3/16" thick, although the Crowe NamePlate Company is furnishing a metalpanel, beautifully engraved and finished,which can be used in this set without anyloss of efficiency.

In the rear there -are two panels 2,4x3,4" and two 9Vzx3Y2", all of 3/16"

Celoron.No engraving for the binding posts is

called for, for Eby posts have been usedthroughout. If you can't get a bindingpost engraved B- C+, use a plain bind-ing post and scratch the markings on ityourself, filling them in with white crayon.

Just to bring the binding post arrange-ment right up to the minute, we used ared Eby binding post for the 135 volts.As a matter of fact it is well to be a littlecareful in handling that lead for, although135 volts is not dangerous, it is possibleto get a slight kick from it.

Tubes for the SetEither a UX199 tube with a Pacent

Isolantite adapter or a UV201A tube canbe used in the RF stage.

We are inclined to prefer the 1.11/201A

,se By M. B. Sleeper

THE RADIO SIDE of the circuit, viewed from the bottom, the antenna coil beingat right. Note the method of mounting the Amperite under the RF socket.

as being more sensitive, although it may" be easier to neutralize the UX199. Wedo not recommend the UV199 with anadapter because adapters for UV199s toooften develop contact troubles.

The UV201A as a detector is entirelysatisfactory in this set for all ordinarypurposes but, as has been stated previous-ly, the Donle tube gives a very definiteincrease in distance, volume, and quality,certainly more than enough improvementto justify the increased cost.

The first and second amplifying tubesshould be Daven Mu -20, with a DavenMu -6 for the last stage. These threeaudio tubes were chosen -because theyoperate directly from 6 volts and do notrequire a rheostat. For this reason, it iswell to watch the storage battery so thatit will not drop appreciably below 6 volts.

Other types of amplifier tubes can beused provided they are the equivalent ofthe Daven tubes in their electrical char-acteristics.

Binding posts on this set call for 22,4,67%, 90, and 135 volts.

The current drain on the set with 9volts C battery for the last tube, with aUV201A for the RF amplifier, Donle de-tector tube, two Mu -20 and one Mu -6 isdivided as follows : RF tube, 1.75 milli-amperes, Donle detector tube, 0.1 M.A.,first two AF tubes, 2.75 M.A., and the lastpower tube 5 M.A. This is with a 9 -

volt C battery on the last tube.It is interesting to note that strong

DETAIL of the bottom of the detector -AF unit. The detector tube is at right.The impedaformers are shown underneath, with the audio leaks mounted thereon.

signals decrease the current in the lasttube, instead of increasing it. Therefore,the total drain fluctuates between 7 and10 M.A.

The Acme B eliminator is quite satis-factory for this outfit. The low voltagebinding post on the eliminator shouldgo to the B-1-22 volts binding post on theset and the high voltage tap should beconnected to the B-1-67,4, B+ 90, andB+135 posts. That puts the full voltageon the RF and AF tubes.

Installation NotesThirty or forty miles from New York

City, the KB -8 gives as sharp tuning asanyone can ask of a set, even when itis operated on a 100 -ft. single wire anten-na. This is a convenient size, not toobig, but large enough for good pick-up.With a 75- or 100 -ft. antenna the rangeis equal to any of the very best receivers.

In congested areas where there are anumber of broadcasting stations operatingsimultaneously, it is necessary to reducethe antenna to 25 or 30 ft. The groundlead should not be more than 10 or 15ft. If it is necessary to use a longerground lead, reduce the length of theantenna accordingly. Then the tuningwill be sharp enough to cut out localinterference. The ability to use the KB -8on such a short antenna makes it par-ticularly well suited for installation inapartment houses where an outdoor an-tenna is not practical.

Any standard 7x24" cabinet can be usedfor the KB -8, allowance having beenmade around the edges of the panel sothat the parts behind will not interfere.A depth of 7-1/6" is required.

On general principles we do not recom-mend a cabinet which has a loudspeakerchamber built as a part of the cabinet.Often mechanical vibration froM the loud-speaker causes the tubes to howl. How-ever, a cabinet such as the Jewett RadioHighboy, which has a separate papier-mache sound chamber mounted at theback of the cabinet, with the bell comingup to a screened opening, does not developthat trouble.

It is advisable to have the B batteryeliminator mounted a slight distance fromthe set itself, and not directly behind itin the same compartment, although wehave not had any difficulty with the Acmeeliminator in this respect.

THE 4 -TUBE DIAMOND OF THE AIR. byHerman Bernard. appeared in RADIO WORLDdated Jan. 23. Hc. per copy. or start subscriptionwith that number. RADIO WORLD. 145 W. 45thSt.. N. Y. C.


A 2 -Tube Eliminator

FIG. I, looking down upon the com-pleted eliminator in the cabinet.

By Lewis WinnerAssociate, Institute of Radio Engineers

[Part I of this article on the constructionof a B battery eliminator which rectifiesboth sides of the wave was Published lastweek, issue of March 13. The conclusionfollows.]

PART IIC ONNECT the leads of the cord to

the terminal in the plug. Do notyet connect the B terminals to the set.Screw the plug into the line socket. Thetube should light fairly bright and makea very slight hum, which can be heardonly by placing your ear close to the tube.Disconnect the line now and connect theB terminals to their respective places onthe receiver. Connect the line to the

LIST OF PARTSOne AC 220 -volt step-up transformer

(Shore).Two 30 -henry choke coils, L1L2 (Shore).Two .5 mfd. fixed condensers, Cl C2

(Aerovox).One S or 1 mfd. fixed condenser, C6

(Aerovox).One condenser unit; one 3 cafe,: fixed

condenser, C3; one 2 mfd. fixed condenser.C4; one 6 mfd. fixed condenser, CS (Aero-vox).

One variable resistor, Clarostat, R2(American Mechanical Laboratories).

One 10,000 ohm fixed resistor, Rl (Aero-vox).

Two rectifying tubes (Tectron).Two sockets, standard base.One socket for input voltage.One switch, S.One panel.One fuse, F.One socket for holding fuse.Accessories: Lamp cord, aluminum

brackets, screws, nuts, cabinet, flexiblewire, binding posts, Insulating strips, etc.

eliminator. Do not place the eliminatorvery close to the set. That is, thereshould be at least a 2 -foot separation be-tween the two. The strength of the sig-nals can be increased or decreased bythe varying of the voltage, through themeans of the variable resistor, R2.

Now as to the detailed information re-garding the chokes, transformers, alumi-num strips, panel and special cabinet.The transformer used was one that waswound by machine. That is the reasonfor no transformer head, etc., being em-ployed. However, those who wish towind their own may consult my descrip-tion in the Dec. 19 issue, on pages 12 and13 in conjunction with that given here-with.

The machine employed to wind thetransformer produces a solid foundation,wraps a layer of insulation between every100 turns, paraffines the ends of thewindings, so as to keep the windingsrigid, and places a covering over the com-pleted winding. An adjustor is set to thedifferent number of turns, which auto-matically stops, as the required number ofturns is reached. This same proceduremay be followed, with the use of a hand -winding machine, if the person is verycareful. It is not difficult, but plenty ofpatience is required.

A solid foundation may be made bytaking a common cotton spool, with adiameter of 1", and pouring hot paraffineover. The layer formed should be ,4"thick. This foundation should be fittedon the spool of the winding unit. Alayer of manila paper .005", thick shouldbe placed over this paraffine, so that whenwinding, the wire will not cut. Layers ofpaper are placed over every layer ofwire. You can either bring the leadsfrom the winding direct to the respectiveterminals or make a bracket as is seenin Fig. 2, of last week's issue. A pieceof insulating strip is placed over the alu-minum strip where the binding posts areto be placed and the leads then arebrought to their respective positions.

In order to mount the condensers,sockets, etc., you have to use aluminumstrips, the dimensions of which are givenherewith.

Procure an aluminum strip, 9.3/A" longand 1" wide. Bend as per Fig. 4. (1).This strip is used for mounting the con-denser bank and the sockets. Drill holesfor mounting the sockets. The exactpositions of these holes will not be givenas they vary for different sized sockets,

FIG. 2 (top), showing the back ofcabinet. Note the holes, which allowair to enter and cool the tubes, incase they have become overheated.The input voltage socket is at thebottom. Fig. 3 (bottom), showing thefront of the cabinet with the threebinding posts and the variable re-

sistor knob.no special make being necessary. Laythis aside. Now procure two pieces ofaluminum stripping, 33/4" in length and

in width, Fig. 4 (2), used for con-

-0-

CONNECTING STRIP

246"

SOCKET STRIP

FIG. 4, showing the different dimensions of the aluminum strips required.

1"

March ZO, 1926 RADIO WORLD 13

Choke Coils for Tectronnecting the laminations of the choke coils,using the closed core style (Fig. 6). Thelast piece of stripping required is that forthe socket. This is 3YR" in length and21/4" in width and is seen in Fig. 4 (3).By following the template, shown lastweek, the holes for the mounting of thestrip on the baseboard, may be obtained.For the positions of the holes holding theinput voltage socket, it is best to makethe measurements direct from the typeof socket employed, as the size and posi-tions vary.

As was explained last week, there aretwo methods of making the cores for thechoke coils. The methods are shownclearly in Figs. 5, 6, 7, 8 and 9. In theclosed core method, instead of placing thelaminations in alternate layers as pertransformer, they are placed as per Fig.9. That is, there are two stacks of 60laminations banked. They are thenplaced through the center of the windings.A piece of manila paper, of .005" thick-ness is placed between the laminations.This is shown in Fig. 5: This is doneonly at one point, although there aretwo places as per Fig. 9. The aluminumstrips are then placed through the wind-ings and over the laminations, as perFig. 6.

Bolting the LaminationsScrews running through the holes on

both the strips and laminations are thenbolted. With the shell type of core, thelaminations are just slipped through thecenter of the winding. This is shown inFig. 7. Here the laminations have nor-mal gaps. This is also shown in Fig. 8.Therefore no paper is necessary to placebetween laminations. The laminationsfor this shell type core, have the follow-ing dimensions according to Fig. 8: A isYR" B is 34" while C at the top is,A". This means that between B and thetop of C there is a Y4" reduction. The

A

a

A

A 0 A

SHELL TYPELAMINATION

FIG. 8, showing the shell typelamination. Note the normal gap,

also the decreasing in width of C.

3 8"

FIG. 9, showing the method of plac-ing the laminations, so as to make aclosed core. A is the piece of paper

making the gap.

FIG. 5 (top), placing a piece of manila paper between laminations. Fig. 6 (left),showing the aluminum connecting strips, over the laminations and through thecenter of the choke coil, employing the closed core method. Fig. 7 (right), showingthe shell type lamination placed through the core. Note the difference in size be-

tween the windings, where the closed core and the shell core are used.

holes are 'A" from the top and the bottomof B and C.

Angle irons are placed at the bottomof the cores, so that they may be mountedon the plate.

The panel for the mounting of the vari-able resistor and binding posts is shownin Fig. 10. The center hole is for thevariable resistor. The three top holes arefor the binding posts. The two bottom

4-

I

H-----2

tPANEL roa RHEOSTAT AND BINDING POSTS

FIG. 10, showing the panel. Notethat the arrangement of the holes onthe bottom are for the placing of thepanel on a simple baseboard. How-ever, when using the panel in thecabinet, the holes should be in thesame level, on both top and bottom,e.g., 1/4", while the distance of theholes from the edges is Y8", instead

of 15/16".

holes are for the mounting of the panelon the baseboard, as per Fig. 4, last week.

If so desired, the complete eliminatormay be placed in a steel cabinet, as perFigs. 1, 2 and 3. The cabinet shown isa rough laboratory model, which wasmade out of sheets of tin. I would notadvise the layman to attack this proposi-tion, as they can be purchased for a verysmall price from the Shore Electric Co.

Bt Amp

B. Del.

FIG. 11, showing a method of placingvariable resistors, whereby both theamplifier and the detector voltage maybe varied. The varying of R2 willchange the value of R3. This, how-ever, does not apply vice versa action.Therefore, do not attempt to adjust

R2 and R3 at the same time.

BAD PRACTICE TO USE NEW BBATTERY WITH OLD

It is not good practice to place a wornout B battery with a fresh B battery, asthe new batery will be run down veryquickly, due to the high internal resist-ance of the worn out battery. By pur-chasing a fresh pair of batteries, thesaving in comparison as to when usingthe old one and the ne wone, will be be-yond comparison. As soon as the B bat-teries (45 volt type), are run down, sothat they read 35 volts, it is high time tothrow them out.


Radio UniversityAFREE Question and Ans-

wer Department con-ducted by RADIO WORLDfor its subscribers only, byits staff of Experts. AddressRadio University. RADIOWORLD. 145 West- 45th St..N. Y. City.

FIG. 276, showing the amplifier diagram,PLEASE GIVE a schematic diagram of

a 2 -stage transformer coupled audio -fre-quency amplifier for use with 01A type tubes,with a C battery inserted in series with theF posts of the AFT; a variable resistorshunting the secondary of the second AFTand a fixed by-pass condenser shunted acrossthe output. I would like to have the con-stants stated also.-James McDonall, Passaic,N. J.

- Fig. 276, shows the diagram. Both thetransformers should be of the low ratio type.RI is 6 ohm, ampere variable rheostat.R2 is a 500,000 ohm variable resistor. Theby-pass condenser which is shunted acrossthe output (drawn in dotted lines, as it isnot absolutely necessary) is of the .001mfd. fixed type. If you are going to place90 volts on the plate of these tubes, thena 4.5 volt C battery should be used. Ifyou are going to place 135 volts on the platesof the amplifier tubes, then a 9 volt C batteryshould be used. The P post on the firstAFT goes to the plate output of the detectorcircuit.

* *

REGARDING the Victoreen, as pic-tured in your issues of February 20, 27,Match 6 and 13, is the approved layoutof parts shown? I have seen differentarrangements.-Dinny Reinitz, 127AClarkson Ave., Brooklyn, N. Y.

The set shown in the photographs pub-lished in those issues is orthodox andthe layout should be followed. That setwas built for experimental purposes byPaul R. Fernald, c -o H. & F., 168 Wash-ington St., N. Y. City.

* * *

I AM very much interested in the Ber-nard 1 -Tube set, which appeared in theOctober 24 issue of RADIO WORLD. I havetwo .0005 mfd. variable condensers, whichI would like to use instead of the .000375and .00025 mfd. variable condensers speci-fied. What would be the correct numberof turns to place on Ll and L2 so thatthese condensers may be employed?-Leslie James, 312 Estelle St., Houston,Tex.

The primary winding, Ll, no matterwhat capacity a or Cl may be, is thesame, 10 turns. This is wound on a tub-ing a 3g" in diameter and 4" high. UseNo. 22 double cotton covered wire. Thesecondary, L2, is wound on the sametubing. There is a g" separation betweenthe two windings. This secondary con-sists of 45 turns. However, there is atap made on this secondary, which islocated at the third turn from the be-ginning. It is preferable to use a .00025mfd. variable condenser, instead of the.0005 mfd. variable condenser, as regen-eration is easier to control. If the latteris to be used, then make the tap at thesecond turn.

* *

IN REFERENCE to the 3 -tube 3 -circuittuner receiver, described in the October10 issue of RADIO WORLD by Capt. P. V.O'Rourke. (1) What ratio audio-frequen-

B+Amp13-A+A-

0 B+Det.Mr. McDonall requested.

cy transformers should be employed? (2)Please state the number of turns to placeon a form 3%" in diameter and 3" high,to constitute the primary and secondarywindings of the tuner? (3) How manyturns should be placed on a form 3" indiameter, to constitute the tickler wind-ings? The tickler is to be wound withNo. 26 single silk covered wire, while theprimary and the secondary windings areto be wound with No. 22 double cottoncovered wire. The secondary winding isto be shunted by Remler .0005 mfd. vari-able condensers. (4) Are these conden-sers all right to use here? (5) I triedto get a .00025 mfd. fixed by pass con-denser, but the clerk told me that theywere the same as the plain .00025 mfd.fixed condensers. Is this true?-CaryClenenger, 1518 Pauline Ave., Rockford,Ill.

(1) Both transformers are of the lowratio variety. (2) The primary windingconsists of 10 turns. The secondary wind-ing consists of 45 turns. There is a A"separation between the two windings. (3)The tickler winding consists of 36 turns.(4) Yes. (5) Yes.

* *

I HAVE constructed the 3 -tube 3 -cir-cuit tuner described in the October 10issue of RADIO WORLD by Capt. P. V.O'Rourke, but am having some trouble.Only the local stations come in withvolume. I cannot make the set oscillate.The tickler has no effect. I am using astandard tuner, with a 10 turn primary,45 turn secondary, wound on a tubing3%" in diameter and a 30 turn ticklerwound on a tubing 2%" in diameter. No.22 double cotton covered wire is used towind the primary and the secondary, whileNo. 26 single silk covered wire is used towind the tickler. How can this troublebe remedied?-Elton Jackson, 1706 TexasAve., Houston, Tex.

Add 10 turns to the tickler coil. Re-verse the leads from the tickler. Try asmall fixed condenser across the tickler,say .00025 mfd.

* * *

I AM about to build the 1926 ModelDiamond of the Air, but before doingso I would like to have some informa-tion. (1) I have a Daven 3 -stage re-sistance coupled audio -frequency ampli-fier, with two Daven hi -mu 20 tubes andone Daven lo -mu 6 tube. Would it bepractical to use this after one stage oftransformer coupled AF amplification, orwould it be advisable to cut out thetransformer stage and just use the threestages of resistance coupled AF ampli-fication? (2) If I use a transformerof the 2 to 1 ratio type and then followit with the resistance coupled AF ampli-fication, would the volume be too greatfor a common phonograph unit loudspeaker?-J. P. Smith, Chester, Pa.

(1 and 2) It would not be advisable touse the transformer stage in this case.The resistance stages will suffice amply.

I WOULD like to know if the follow-ing method of hooking up a two stageaudio -frequency amplifier, to a step oftuned RF and a regenerative detector,using a 112 tube in the last stage is allright? The G post on the first AFTgoes to the G post on the socket holdingthe first AF tube. The P post on thissame socket goes to the P post on thesecond and last AFT. The F minus poston this socket goes to a terminal of aballast resistor, the other terminal goingto the A minus post of the battery. TheF plus post of this socket goes to theA plus post. The F post on the firstAFT goes to the minus post of a 4.5 Cbattery, the plus post going to the Aminus post. The B plus post on thesecond AFT goes to the 90 volt post onthe B battery. The G post on the sec-ond AFT goes to the G post on the lastsocket. The P post of this socket goesto the top terminal of the single circuitjack. The bottom terminal of this jackgoes to the 135 vo terminal on the Bbatteries. The F post on the AFT goesto the minus post of a 9 volt C battery.The plus post of this battery goes to theminus post of the A battery. A ballast -

resistor is in series with the negative legof the filament. The F plus post of thissocket goes to. the A minus post. (2) Isit necessary to place a .001 mfd. fixedcondenser in series with a choke coil, -which is in series with the P post on thelast socket, the other terminal of whichgoes to the 135 volt post, while the otherterminal of the fixed condenser goes tothe top terminal of the jack, with thebottom terminal of the jack going to theA minus post, instead of the P. plus postso as to obtain quality reception?-SolMichael, 1615 Townsend Ave., Bronx, N.Y. City.

(1) The wiring of the amplifier is 0. K.(2) No.

* *

IS IT possible to add two stages ofaudio -frequency -amplification to the 1 -

tube receiver, described by Wm. Merceron page 17 of the Feb. 20 issue ofRADIO WORLD? (2) If so, a description ofit, would be very much appreciated.-T. E.Crawford, 1534 Emily St., Philadelphia, Pa.

(1) Yes. (2) First make a 100 -turnchoke coil, wound on a tubing 1" in dia-meter, using No. 30 single silk coveredwire. Insert it in series with the plateof the detector tube and the top terminalof a double circuit jack. The secondterminal from the top goes to the platepost of the AFT. The third terminalfrom the top goes to the B post on theAFT. The bottom terminal goes to theB plus 22% terminal. The G post on thissame AFT goes to the G post on thesocket holding the first AF tube. The Fpost on the AFT goes to the F post onthe next AFT. This then goes to theminus post of a 4.5 C battery. The pluspost of this C battery goes to the minuspost of the A battery. A ballast resistoris placed in series with the negative legsof both the tubes. The F plus postsgo to the A plus post. The P post o'n thesecond AFT goes to the P post on thefirst AF socket. The G post on this AFTgoes to the G post on this same socket.The P post on the last socket goes tothe top terminal of a single circuit jack.The bottom terminal goes to the 90 voltterminal.

* * *

I WOULD like to have the circuit dia-gram of a 4 -tube set, employing a regener-ative detector, with the 3 -circuit tuner and3 stages of resistance coupled audio -fre-quency amplification. The constants of thevarious parts which make up this receiverare also requested. A rheostat should con-trol the filament of the detector tube, whileone ballast resistor should control the fila-ments of the three amplifier tubes.-HenryUkarts, New Lebanon, N. Y.

Fig. 277, shows the 4 -tube receiver. The

weti14,40


FIG. 277, showing a 3 -circuit tuner with resistance coupled AF.

B B, A A B2 I.E. A

FIG. 278, showing

tubing, upon which the primary and thesecondary, L1L2, is wound is 31/4" in dia-meter and 4" high. The primary, Ll, con-sists of 10 turns. The secondary, L2, con-sists of 45 turns. No. 22 double cottoncovered wire is used. There is a 34" separa-tion between the two windings. The tickler,L3, is wound on a tubing 214" in diameterand consists of 36 turns. No. 26 single silkcovered wire is used. A .0005 mfd. variablecondenser is shunted across the secondary,L2. The grid condenser, C2, is of the .00025mfd. fixed type. A 2 megohm grid leak,RI, is also used. R2 is a 10 ohm rheostat,with a carrying capacity of % amperes. C3is a .001 mfd. fixed condenser. C4, C5 andC6 are all .25 mfd. fixed condensers. R3,R5 and R7 are all .1 megohm resistors. R4is a .5 megohm resistor. - R6 and R8 are .1megohm resistors. R9 is a 44 ampere bal-last resistor. The -01A type tubes are em-ployed. It is advisable to use a 6 volt Cbattery, in series with the F- posts of thelast socket. J is a single circuit jack.

* * *I WOULD like to have the circuit dia-

gram of a 5 -tube set, in which quality re-production is stressed. A regenerative de-tector, using a 3 -circuit tuner, should beused. Please state the constants of all theparts.-Robert James, Newport Center, Vt.

Fig. 278, shows such a diagram, Ll andL3, the primaries consists of 10 turns. I2and L4, the secondaries, consists of 45 turns.The tubing that these windings are placedupon is 3%" in diameter and 4" high. No.22 double cotton covered wire is used here.The tickler is placed on a tubing 23/4" indiameter and consists of 36 turns of No. 26tingle silk covered wire. C2 and C4 are.0005 mfd. variable condensers. Cl is a.005 fixed condenser. C5 is a .001 mfd.fixed condenser. C6, C7 and C8 are all .01mfd fixed condensers. R4 is a 500,000 ohmpotentiometer. RI is a 1 or 2 megohm gridleak, R2 is a 10 ohm rheostat. R3, R5 andR7 are 1-A Amperites. R6 is a .5 megohmgrid leak. R8 is a .25 mcgohm grid leak.

the schematic diagram of

1.6, L7 and L8 are autotransformers. S isa filament switch. Now as to the tubes em-ployed. It will be seen that the filamentsof the first two tubes are connected in series,while the filaments of the other tubes, whichare the amplifiers are connected in parallel.The 99 type tubes are used as the RF andthe detector stages, while the O1A tubes areused as the amplifiers. The 99 type tubesrequire 60 milliamperes at 3 volts. Hencetwo of these tubes may be connected in seriesand then placed across a 6 volt battery. Thisis what is done in this receiver. These tubeswill operate well until the voltage fallsto about 5.8, when it may be considered asfully discharged. In that case, the leastvoltage across the terminals of each tubewill be 2.9, only .1 less than normal. Thepower saved when two are connected inseries is .36 watt and the current saved, of

the quality receiver.

course is 60 milliamperes. You thereforeobtain the efficiency of two tubes, whileonly using the power of one tube.

* * *

I AM desirous of purchasing a conespeaker for use with the 1926 ModelDiamond of the Air. Will the CrosleyMusicone loud speaker be satisfactory foruse in conjunction with this set?-G. T.Garnett, 116 West Grace St.

Yes.* * *

WHERE COULD I get information re-garding the 1 -Dial 6 -tube sensitive DXgetter, which is shown on the bottom ofpage 12 in the Dec. 26 issue of RADIOWORLD ? -J. A. Kukuk, Brookings, S. D.

See Capt. P. V. O'Rourke's article inthe July 11 issue of RADIO WORLD.

Join RADIO WORLD'S University ClubAnd Get Free Question and Answer Service for the Coming 52 Weeks.

Have your name entered on our subscription and University lists by special number.Put this number on the outside of the forwarding envelope (not the enclosed return,envelope) and also put it in your queries and the questions will be answered the sameday as received. If already a subscriber, send $6 for rewenal from close of presentsubscription and your name will be entered in the Radio Univrsity.

[In sending in your queries to the University Department please paragraph them so thatthe reply can be written under or alongside of each query. Write on one side of

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Enclosed find $6.00 for RADIO WORLD for one year (52 Nos.) and also enter myname on the list of members of RADIO WORLD'S University Club, which gives mefree information in your Radio University Department for 52 ensuing weeks, and send

me my number indicating membership.

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Testing Broken Cables by Radio

A NOVEL and ingenious method of finding out where broken cables are present,with the use of a radio receiver, has been put into use by some large power com-panies in the eastern portion of the United States. A super -sensitive receiver,employing a loop as the collector of energy, is used to detect the stray noises.

(Underwood & Underwood)

Telephoning ProgramCheers up a Patient

PROGRAM coming through speaker being delivered into telephone (left) andbeing received by a patient, miles away, who has no radio accessible (right).

If a speaker, with the usual volumeoutput, is placed with the nearest emit-ting point not less than 3%" from the edgeof a telephone receiver, as shown in photoat left, you may call up some one who issick and let him or her listen to a snacthof program. Of course this should not bekept up long, despite the beneficient ef-fort, because the telephone lines shouldbe kept open for the normal traffic. Yeta sick and tired patient may be cheeredup by a snatch of music heard during thispleasant interval.

The patient is called on the phone inthe usual way and the telephone receiveris placed on the table when the patient isready to receive the music. If the patient

has a telephone at her bedside the musicmay be heard plainly and comfortably ifthe afflicted one's telephone receiver islaid on a pillow with the diaphragm evena few inches from the ear.

At the patient's end greater volumewould be obtained if the telephone re-ceiver were placed against a regularspeaker unit, used for the nonce as amicrophone, the unit cords connected tothe input of an audio amplifier. Thena speaker or earphones could be used forreception. At places where headpiece re-ceivers are used in regular telephony ofcourse the problem is simplified, for thetelephoned signals are snugly received, asshown in the photo at right.

Divide StaticNationals c

Senator ,

By C. C. DillUnited States Senator from Washingtonand author of the Dill Radio Bill now

pending in Congress.

RADIO during the last two years hasbecome a source of real public serv-

ice. It has gradually passed beyond theexperimental stage and reached the pointwhere the people of this great countrymay rely on it for entertainment and in-struction.

I do not mean that`radio developmenthas reached perfection. I gather fromengineers and scientists with whom I havediscussed the subject that much greaterimprovements may be expected in trans-miting and receiving apparatus, and thatwe may also have radio vision within thenear future.

The Task of CongressIt is with the thought of dedicating this

great service to the permanent use of thepeople as a whole that Congress is at-tempting to frame legislation for its regu-lation. There seems to be no doubt thatregulation is necessary and that a newradio law is needed immediately.

The question has arisen during ourconsideration of the bill as to whether theregulation of radio should be entrusted tothe Secretary of Commerce or to anyother one man. It is my belief that at thepresent stage of development, the detailsof administration should remain with theDepartment of Commerce, but that a non-partisan commission should be establishednow with authority to pass finally uponquestions which may be referred to it bythe Secretary of Commerce or any oneelse. The decisions of this commissionshould, of course, be subject to review inthe courts.

Service CurtailedA highly important feature connected

with the administration of the radio lawis the number of stations required to servethe American public. Due to the servicearea limitation imposed upon broadcastingstations by weather conditions and otherforms of interference it would seem as ifa large number of stations would be nec-essary.

Under the present arrangement thereare 89 wavelengths and 536 stations.There are applications on file at the De-partment of Commerce for 400 more newstations.

The crowding of 536 stations on 89wavelengths has practically rendered un-serviceable a large portion of the broad-casting band. I am by no means an ex-pert on radio, but I am a fan with theaverage appreciation of programs andwi'h the average desire to pick up a widevariety of stations.

Interference TroublesomeThe broadcasting band is divided into

two sections. From 545 to 280 meters isgiven to class B, or the higher grade of

stations. From 280 to 200 meters are the


s Intod Locals,ill Suggestss A stations. Tbp class B section wasvded to capacity many months ago and=her of those stations was placed inclass A band.rom my experience with my set andn what I have been told, there are soty stations between 280 to 200 meters: it is difficult to get any of them with -interference. Even in the Class B

d the separation is none too great andTference is sometimes experienced.ecause of the congestion in the class'and it seems as if these valuable wave_;ths are almost entirely lost to thelic. This presents a grave problem toTress. I think, however, it is a prob-of administration and that legislation

;uld be enacted to give some agencyhority to correct this situation.

, Urges Re -allocationthink I know of a solution which al -ugh easy to put on pap& might bey difficult to work out.3roadcasting stations should be dividedo two classes according to their powerrational and localstations. The mostd standards should be set up for the

:ional stations and they should, whensible, be given wavelengths to permitir being heard by the public without

erference.kn entirely new allocation of wave-gths should be made on this basis. Astain number of wavelengths should be;erved for national stations and a num-r for local stations. Because of thev power limitation which should beiced on local stations, it might be pos-;le to put all of them on three or fourvelengths.The present class A band should beallocated and confined to'a number ofitions which could render service with -t interference. The stations in the classband should be given the chance to

alify as either national or local stations,d wavelength assignments made toem accordingly.An entirely new band of wavelengthsould be opened up for broadcasting-e band between 150 and 200 meters, andit should be placed some of the stationsuch are causing the congestion in theus A band. The assignments of wave-gths should be on a basis which would

cognize the right of every section of theuntry to have sufficient stations to pro -e good radio service._

Praise for the HamsTo put the broadcasting stations in thend between 150 and 200 meters would,course, mean that the amateurs woulddeprived of those channels. I have the

eatest amdiration for the amateurs ofis country, most of them boys. With -it them, broadcasting would never haveached its present stage of development.it the amateurs would still have thend between 100 meters down and I, fore, predict that they would cheerfullylinquish this belt and work on the lowervelengths, as they largely do now.

Copyright, 1926, by Stevenson Radio Syndicate)

Lauder Joins English Hospital Fans

SIR HARRY LAUDER visited the Cheyne Hospital for children and listened inon the radio which has just been installed. Evidently Sir Harry is enjoying it as

much as the little patients in the hospital in England. (W de World.)

Deaf, Hears in Odd Way

DEAFNESS does not prevent ElmerF. Tanner, of East Boston, from en-joying his radio, for he has discoveredthat the earphones of his set placedover his temples, as shown in thephoto, enabled him to hear as well as aperson not so handicapped. Hemisses practically nothing that comesthrough the air from the variousstations. Many inexplainable instanceshave arisen where the deaf heard byradio for the first time. (Underwood

& Underwood)

It's a Sad Story, Mates!

"THE BOOK OF REGRETS"-Thebook of the radio section of theUnited States Department of Com-merce which contains more than 400applications for radio broadcasting li-censes, all of which have been regret-fully denied. This photograph showsJ. E. Downey, an assistant to ChiefRadio Supervisor W. D. Terrell.

(Harris & Ewing)

Avoid This Crash and Save Some Cash

TO AVOID THIS DO THIS FIRSTA speaker's life may be spared simply by being careful to disconnect the speakerplug from the set before you move the set to some other location in your home.(Hayden)











Divide StaticNationals

SenatorBy C. C. Dill

United States Senator from Washingtonand author of the Dill Radio Bill now




I do not mean that`radio developmenthas reached perfection. I gather fromengineers and scientists with whom I havediscussed the subject that much greaterimprovements may be expected in trans-miting and receiving apparatus, and thatwe may also have radio vision within thenear future.












is Into!d Locals,ill Suggestsis A stations. The class B section waswded to capacity many months ago andlumber of those stations was placed inclass A band.

;rom my experience with my set andm what I have been told, there are sony stations between 280 to 200 meters.t it is difficult to get any of them with -t interference. Even in the Class Bid the separation is none too great anderference is sometimes experienced.3ecause of the congestion in the classband it seems as if these valuable wave-gths are almost entirely lost to theblic. This presents a grave problem tongress. I think, however, it is a prob--a of administration and that legislationmild be enacted to give some agencythority to correct this situation.

Urges Re -allocation: think I know of a solution which al -)ugh easy to put on paper might be.y difficult to work out.3roadcasting stations should be dividedo two classes according to their powerrational and localstations. The most-id standards should be set up for thetional stations and they should, whenssible, be given wavelengths to permitair being heard by the public withouterference.kn entirely new allocation of wave-igths should be made on this basis. Artairi number of wavelengths should beserved for national stations and a num-r for local stations. Because of theAI power limitation which should beaced on local stations, it might be pos-Ile to put all of them on three or fourivelengths.The present class A band should beallocated and confined to' a number ofations which could render service with -t interference. The stations in the classband should be given the chance to

ialify as either national or local stations,d wavelength assignments made to

em accordingly.An entirely new band of wavelengthsould be opened up for broadcasting-e band between 150 and 200 meters, andit should be placed some of the stations

itch are causing the congestion in theass A band. The assignments of wave-agths should be on a basis which wouldcognize the right of every section of theuntry to have sufficient stations to pro-le good radio service -

Praise for the HamsTo put the broadcasting stations in the;tad between 150 and 200 meters would,

course, mean that the amateurs woulddeprived of those channels. I have the

eatest amdiration for the amateurs ofis country, most of them boys. With -it them, broadcasting would never haveached its present stage of development.ut the amateurs would still have theand between 100 meters down and I, foris, predict that they would cheerfullylinquish this belt and work on the lowersvelengths, as they largely do now.;Copyright, 1926, by Stevenson Radio Syndicate)


SIR HARRY LAUDER visited the Cheyne Hospital for childrOn and listened inon the radio which has just been installed. Evidently Sir Harry is enjoying it as

much as the little patients in the hospital in England. (Wide World.)



& Underwood)



(Harris & Ewing)









If a speaker, with the usual volumeoutput, is placed with the nearest emit-ting point not less than 3,,/," from the edgeof a telephone receiver, as shown in photoat left, you may call up some one who issick and let him or her listen to a snacthof program. Of course this should not bekept up long, despite the beneficient ef-fort, because the telephone lines shouldbe kept open for the normal traffic. Yeta sick and tired patient may be cheeredup by a snatch of music heard during thispleasant interval.




Divide Static,Nationals

Senator 4,

By C. C. DillUnited States Senator from Washingtonand author of the Dill Radio Bill now


RADIO during the last two years hasIX become a source of real public serv-ice. It has gradually passed beyond theexperimental stage and reached the pointwhere the people of this great countrymay rely on it for entertainment and in-struction.

I do not mean that radio developmenthas reached perfection. I gather fromengineers and scientists with whom I havediscussed the subject that much greaterimprovements may be expected in trans -tufting and receiving apparatus, and thatwe may also have radio vision within thenear future.












Ins Intolid Locals,)ill Suggestsass A stations. Thee class B section was-owded to capacity many months ago andnumber of those stations was -placed in

;ae class A band.From my experience with my set and

rom what I have been told, there are soany stations between 280 to 200 meters.tat it is difficult to get any of them with -at interference. Even in the Class Band the separation is none too great andnterference is sometimes experienced.

Because of the congestion in the classt. band it seems as if these valuable wave-nigths are almost entirely lost to theablic. This presents a grave problem tocongress. I think, however, it is a prob--m of administration and that legislationhould be enacted to give some agencyuthority to correct this situation.

Urges Re -allocationI think I know of a solution which al -

hough easy to put on pap& might beery difficult to work out.Broadcasting stations should be divided

nto two classes according to their power-national and localstations. The mostigid standards should be set up for theational stations and they should, when)ossible, be given wavelengths to permitiheir being heard by the public withoutnterference.

An entirely new allocation of wave-engths should be made on this basis. ACertain number of wavelengths should bereserved for national stations and a num-er for local stations. Because of thelow power limitation which should belaced on local stations, it might be pos-

sible to put all of them on three or fourwavelengths.

The present class A band should bereallocated and confined to' a number ofStations which could render service with-out interference. The stations in the classA band should be given the chance toqualify as either national or local stations,and wavelength assignments made tothem accordingly.

An entirely new band of wavelengthsshould be opened up for broadcasting-the band between 150 and 200 meters, andin it should be placed some of the stationswhich are causing the congestion in theclass A band. The assignments of wave-lengths should be on a basis which wouldrecognize the right of every section of thecountry to have sufficient stations to pro-vide good radio service.,

Praisefor the HamsTo put the broadcasting stations in the

band between 150 and 200 meters would,of course, mean that the amateurs wouldbe deprived of those channels. I have thegreatest amdiration for the amateurs ofthis country, most of them boys. With-out them, broadcasting would never havereached its present stage of development.But the amateurs would still have theband between 100 meters down and I, forone, predict that they would cheerfullyrelinquish this belt and work on the lowerwavelengths, as they largely do now.

(Copyright, 1926, by Stevenson Radio Syndicate)


SIR HARRY LAUDER visited the Cheyne Hospital for children and Iiiitened inon the radio which has just been installed. Evidently Sir Harry is enjoying it as

much as the little patients in the hospital in England. (Wide World.)



& Underwood)



(Harris & Ewing)













Divide StaticiNationals

Senator IIBy C. C. Dill

United States Senator from Washingtonand author of the Dill Radio Bill now




I do not mean that radio developmenthas reached perfection. I gather fromengineers and scientists with whom I havediscussed the subject that much greaterimprovements may be expected in trans-miting and receiving apparatus, and thatwe may also have radio vision within thenear future.












r s Into-d Locals,ill SuggestsS A stations. The class B section wasvded to capacity many months ago andsmber of those stations was placed inclass A band.rom my experience with my set and

,n what I have been told, there are so-dy stations between 280 to 200 meters1 it is difficult to get any of them with -

interference. Even in the Class Bid the separation is none too great and

tnierence is sometimes experienced:ecause of the congestion in the class

4.tand it seems as if these valuable wave-.gths are almost entirely lost to the,lic. This presents a grave problem topress. I think, however, it is a prob-of administration and that legislation

Add be enacted to give some agency3 hority to correct this situation.

Urges Re -allocationthink I know of a solution which al -ugh easy to put on paper might be

s y difficult to work out.3roadcasting stations should be divided3 two classes according to their powerational and local stations. The most

standards should be set up for theional stations and they should, when

pi,sible, be given wavelengths to permitit being heard by the public without

irerference.th entirely new allocation of wave-gths should be made on this basis. Alain number of wavelengths should be

.served for national stations and a num-t. for local stations. Because of theIv power limitation which should bec.ced on local stations, it might be pos-ole to put all of them on three or four

velengths.The present class A band should beallocated and confined to a number of

talons which could render service with -(t interference. The stations in the class

band should be given the chance toLalify as either national or local stations,5d wavelength assignments made tolam accordingly.An entirely new band of wavelengths

uld be opened up for broadcasting-band between 150 and 200 meters, and

it should be placed some of the stationsich are causing the congestion in the

ass A band. The assignments of wave-dgths should be on a basis which wouldognize the right of every section of the

untry to have sufficient stations to pro-le good radio service_

Praisefor the HamsTo put the broadcasting stations in theand between 150 and 200 meters would,course, mean that the amateurs would

t deprived of those channels. I have theeatest amdiration for the amateurs ofis country, most of them boys. With-st them, broadcasting would never haveached its present stage of development.cat the amateurs would still have thend between 100 meters down and I, forle, predict that they would cheerfullylinquish this belt and work on the loweravelengths, as they largely do now.(Copyright, 1926, by Stevenson Radio Syndicate)


SIR HARRY LAUDER visited the Cheyne Hospital for children nd listened inon the radio which has just been installed. Evidently Sir Harry ii. enjoying it as

much as the little patients in the hospital in England. \ ide World.)

Deaf, Hears in Odd Way It's a Sad Story, Mates!


& Underwood)

"THE BOOK OF REGRE Y.-Thebook of the radio section of theUnited States Department of Com-merce which contains more than 400applications for radio broadcasting li-censes, all of which have been regret-fully denied. This photograph showsJ. E. Downey, an assistant to ChiefRadio Supervisor W. D. Terrell.

(fiarris S Ewing




EDWAQD FINCKBANQUET MANAGER_

Notables at the New York Show Short WavesFeatured at

FRANK FRIMMERMAN-ZFZ- FI-002 m'GR

ROBERT T MOQRI5-21305-BUSINESS MGR

GEORGECLARK New York Show

WILLIAM A.BRUNOORUNO RADIO CORP

KENNETH UPTON,HEROIC CHIEF OP-ERATOR- 5 s eoosEvetz

TW. MAC DOWELL--2AAU- EXECUTIVESEC RETARy.

London and N. Y. Talk4 Hours By Radio PhoneAfter three and a half years of inten-

sive experimenting with transatlanticradio telephony, on the part of the Atheri-can Telephone and Telegraph Company,the Radio Corporation of America andthe British General Post Office, successfulconversations were held recently betweenNew York and London by radio telephony,

The American terminus of the highcircuit was in the A. T. & T. building at25 Walker St., N. Y. City, where theformer broadcasting equipment of the A.T. & T. also was located. The other pointwas in the British Post Office in London.

From New York the signals were sentover telephone wires to the radio trans-mitting station of the Radio Corporationof America at Rocky Point, L. I., a dis-tance of 70 miles. Thence they weretransmitted by radio to Wroughton, Eng.,where they were caught by the receivingstation of the British General Post Officeand then sent over telephone wires. The

speeches from London, being sent to theUnited States, were carried by wireeighty-five miles to Rugby and thencesent by radio for 2,900 miles to Houlton,Me., there to be caught by a receivingstation and sent the remaining 600 milesto N. Y. by means of the telephone lines.The wavelength of the station at RockyPoint was 5,260 meters, while the Rugbystation transmitted the signals on awavelength of 5,770 meters. The powerused in transmitting from each end was100 kilowatts.

The volume of the signals on eitherside was so great that frequently thoselistening -in had to tell the party to speakmore softly. More than thirty engineersand newspapermen talked from the tele-phone headquarters in N. Y. City to asimilar group at the British Post Officein London. The feat was hailed as theforerunner of the trans -Atlantic broad-casting of programs.

The Executive Radio Council of theNew York district held itS, sixth annualshow at the Hotel Pennsylvania, NewYork City. The show lasted one week.Short wave transmitters and receiverswere featured. An engineer said that thedevelopment of instruments to receivewaves wider 100 meters is not an indica-tion that all broadcasting will be shiftedto the short wave band. He said that thisshow, unlike the Fall shows, was an ama-teur affair and naturally short wave de-vices were the dominating feature, be-cause amateurs are experimenting in thefield under 100 meters.

Forty manufacturers had booths inwhich complete sets and accesories weredisplayed.

Two short wave transmitting sets werein operation in the ballroom, one operat-ing under the call letters 2ERC and two.others, 2QA and 2ZV.

Visitors at the show throughout theweek were invited to file radiograms forany part of the world. The messages -were broadcast direct over the shortwave route, or relayed by amateur stationsin the American Radio Relay League.

The department of Commerce estab-lished a branch office at one end of theballroom where amateurs took examina-tions for licenses.

The army, represented by Colonel E. T.Hartmann, chief signal officer of the Sec-ond Corps Area, had an exhibit introduc-ing the special equipment developed byarmy engineers for use in the army -ama-teur transcontinental radio .net.

Many of the short wave sets on displaydiffered from the ordinary broadcast re-ceiver in that the tuning coils were inter-changeable and mounted on top of thecabinet so that they could be quickly sub-stituted and plugged into the circuit.These coils were arranged in various sizesand designed to cover a definite waveband. A complete tuning unit coveredfrom 10 to 200 meters (1,500 to 30,000kilocycles). Most of the receivers wereequipped with straight line frequency con-densers and cushion sockets.

Welty Unit Makes SetBuilding Easy

A 3 -tube detector -amplifier on a 9% x434" subpanel is manufactured by William.A. Welty, 36 S. State St., Chicago, Ill.The parts that comprise this unit areof the best. All one need do is to makea 1 -tube circuit, use the first tube as re-generative detector hooked up to this cir-cuit, connect the batteries to binding posts.and plug to speaker jack, and hear veryloud signals on the speaker.

There are two rheostats, one for thedetector, the other for the AF tubes.The grid condenser and bypass condenser.are Micamold, while the two audio trans-formers are Welty. The switch, speaker,.jack, fixed condensers and audio trans-formers are mounted underneath, out ofsight. Lastites are used for soldered con-nections. The subpanel is Bakelite andthe sockets are moulded, too. There arenine binding posts on top, each coloredfor identification. The entire set-up isvery attractive to the eye.

HERMAN BERNARD. managing editor efRADIO WORLD. broadcasts every Friday at 7P. m.. from WGBS, Gimbel Bros., N. Y. City,315.6 meters. He discusses "What's Your Radio Problem ?" Listen in

RADIO WORLD I"March 20, 1926

The Goat At the MikeBy Herman BernardVERY newcomer in a broadcasting

E studio, who is scheduled to take up sometime on the air, is viewed with suspiciort.Until one has proven worthy his merit is

doubted, and often for long thereafter. Thenumerical preponderance of small stations,with their familiar type of talent, abstractsall essence of surprise from this.

But it must be said in favor of studiomanagers, announcers, operators and powerroom executives, that one can not discoveroffhand the doubts that thrive on ignoranceof the performer's qualifications. Thesestudio fixtures have seen so many who weltwilling, eager, but, alas, not able, come andgo, and then not come again, that they drawon a big fund in the bank of experience.

Effective ConcealmentThe concea:ment of the real doubts is so

effective as to be misleading'. Moreover, therule of courtesy that exists, perhaps throughthe grace of executive order, leaves the un-proven genius feeling that he is greatly ap-preciated. As the "artist" stops at the pro-gram board, and catches a gratifying glimpseof his name thereon, he hesitates to moveupon the reception room, or substitute there-for. He may be lucky enough to be recog-nized, otherwise must go through the ordealof self -introduction. The greeting is a fineone. And when finally- he has finished hisbroadcasting the announcer will say "Thankyou," and make him feel that he was reallyworth while, but it is more consoling not toknow that in advance, because pre-kncoleagesomehow robs the expression of some of itssincerity. It is a fact that artists whose artis doubted to the extent of a secret pro-hibitory order on the subject of reappearance,have received thanks in the most gushingvolume.

The AuditionThese remarks may lead some to wonder

what has become of the old-fashioned prac-tice of giving auditions, or private tryouts,before the artist is entrusted to the much -mentioned "unseen audience." It still exists,but the hard practice of supplying a stationwith talent stifficient to cover the allottedhours on the air is like the problem of thepauper who has been bequeathed a palaceand lacks sufficient carpet for the floors.

While some stations give close scrutinyto manuscript speech of some intended orator,most of them do not, especially as men ofreputation resent such censorship, and someof them-in one instance a Major -Generalof the United States Army-actually speakin a spirit of defiance. The soldier I referto was asked to omit a certain paragraphfrom his prepared speech but somehow for-got to do so!

And then there are countless otherexigencies, including non-appearance ofscheduled performers and no musical storeson hand to feed the empty microphone. Asa last resort-an unalterably final one, really-a hurry -call will be sent to some musicpublisher, if the station is in a large city.Then a couple of song pluggers, or maybea trio, as if to make matters 50 per cent.worse, hasten gladly to the studio, and inter-spersed with the reiteration of the songtitles, name and address of the publisher,identity of the 0:imposer, etc. are a fewrhythmic renditions, called popular songs, thepopularity somehow reminding one of a

hope chest.The Welcome Orchestra

A dance orchestra is always a safe bet andthe studio manager or announcer who hasbeen left in a lurch will phone to some caba-ret or hall. He knows that the worst thatcan happen is that only four men show up,instead of the eight or ten expected, and afew discords and faux tempos get on theair. Besides, if an orchestra will play onlysongs that the public prefers at the moment,

any artistic shortcoming always can be for-given-if it is observed at all. Especially ifsongs in which the saxophonist does longsolo stretches of a whining or drawlingnature are included on the program, the dayis safe, or even the night. It is well-knownthat night audiences are more critical thanday audiences, because in the daytime it isso often a case of having to listen to this orthat station, or none, while at night a choiceexists that will suit any one's fancy, and thedials turn easily.

With singers, of course, it is necessary tobe quite careful, as so many persons sufferfrom the hallucination that they can sing, andare confirmed in this 'by their nearest rela-tives and their music teacher, with whombusiness is not so good that he can afford tobe undiplomatic. Most singers, unlessreputed, must suffer the indignity of anaudition, but they may pass that very handilyand yet fail completely before the micro-phone. That is due perhaps to the sympa-thetic frame of mind of the audition conduc-tor, usually a man, and his sympathies arenot so hard to rouse, unless he is listeningto a man! Also, microphone fright makesfailures out of many, because the studiomanager is not likely to risk -many attemptsby one ambitious to succeed. When com-posure finally would be gained-say at thesixth broadcast-the station might have lostits reputation, and as some stations still havesome left, that might be serious.

The TalkersThen we finally get down to talkers. They

are classed as "artists," too, although pro-fessionalism is likely to be utterly absent. Ifthe idea of a talk on a given subject has been"sold" to the studio director or programmanager, the identity or ability of the talkerin most cases hardly is considered. Assum-ing the talker knows what he is going totalk, about, else those sponsoring him wouldnot send him there, the rest is taken forgranted, and he finally treads into the studiowhere so many real artists take regular exer-cise. He gets a fine greeting (from some-body who has been warned to be polite toall comers at the risk of his job) and beginsto feel important. This sensation would beascendant, were it not for the dread he be-gins to feel as the moment for going on theair draws near. He wonders whether heshould read his speech or try to deliver it"extemporaneously." Amid the excitementhe forgets what his decision was, for theannouncer has given the necessary introduc-tion, the talker half stumbles to his chair,and the typewritten speech somehow forcesits way onto the table where the microphoneis perched. Instead of moving closer to themicrophone, for comfort's sake the talker,still silent, moves the microphone nearer him,by dragging it over the table, whereupon theannouncer bursts from the control room,snaps off the microphone from the transmit-ter, and (barring executive orders not totalk loudly) shouts:

"Don't move that mike! You'll breakyour listeners' ears!"

The OrdealFinally the talk is begun. Meanwhile

many rarlioists have been amusing themselves

listening to the carrier wave or have beentaking manual exercise of a rotary natureand have stopped at a certain set of figuresnot representative of this particular station

And what an.ordeal it is to talk! Whetheryou sit or stand, your knees shake. Wordsthat once seemed so easy to pronounce thatyou uttered them while munching cherries,twist themselves about, and syllables becomeas if but the facets of a kaleidoscope. Asyou turn them over with your tongue theyform themselves into things grotesque, untilyou wonder what you are talking about andseem to hear listeners' snickers coming backat you through the microphone! It is thezero hour in this radio life.

The Sign of "Pipe Down"You were allotted ten minutes. You had

forgotten to put your watch on the table.Suddenly the announcer presents himself be-fore you like an ogre, half stretching out hisarm, hand extended, palm down, and pumpsthis arm up and down with a motion fromthe elbow. .Spurred by this gentle warning

you stumble onto the conclusion of your talk,leaving the main threads of it hanging in theair, so that mayhap some passing' wave ofanother frequency will pick them up andtransport them to their proper destination!

"Thank you," says the schooled announcer,smiling -pleasantly, and then proceeds to iden-tify the deliverer of the interesting talk. Yet,if one lingers to listen, he feels that thetransition from that motif to the emphasisof the call letters and the sighless prophesyof the next feature was oddly hurried.

On the way home the newly created artistfeels- proud and wonders why persons in thestreets and cars do not stare at him the waythey would at the Prince of Wales. Beforegetting very far the artist begins to feel agrowing stiffness in his neck and maybe aslight pain in the eye. He can not rentemberthat anybody had hit him in the studio (forconduct is restrainedly gentlemanly there,whatever the natural impulses). He can notunderstand it.

Sees for Second TimeOn the second appearance, just one week

later-supposing that the glib informationpurveyor is granted the privilege of a reap-pearance-he is less uneasy, hence better ableto note his surroundings. For the first time,he sees that the studio walls are heavily cur-tained, and that there are no windows, or, ifwindows are there, none is ever open. Alsowhen he starts to read his manuscript thistime he realizes that the microphone isdirectly before him, hence to speak with his'mouth five frontal inches away from it hehas to put his manuscript on one side, andread it from the corners of his eyes, mean-while straining his neck. Another piece ofclose observation is that an orchestra leavesthe studio as he is about to begin and returnsimmediately after he has finished. This or-chestra, the program week after week willreveal, spends fifty minutes each Friday.evening, doling out "Who," from "Sunny,'"The Prisoner's Song," "Lullaby Lane" andother rare finds of musical quest. At abouthis fourth appearance the talker begins to

(Concluded on poge 30)

20 RADIO WORLD March 20, 1926A THOUGHT FOR THE WEEK"A radio set for every home" is RADIO

WORLD'S slogan. Let's all work to that endfor the glory of radio and the joy ofhumanity.

re. Las are rot. u. .bbDw,.,aw w blanulseturev

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

TELEPHONE BRYANT 0558, 0559PUDLIPHED EVERT WEDNESDAY

Mated Saturday of same week)FROM PUBLICATION OFFICE

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

(Just Eon of Broadway)ROLAND BURKE HENNESSY, President

M. B. HENNESSY, Vice -PresidentFRED F. CLARK, Secretary end Menager

European Representatives: The International News Ce.reams Bidge.. Chancery Lane. London. Ena.

Parte. France: Brentano's. 98 Avenue de l'OperaBan Francisco: Lloyd . Chappell. 656 O'Farrell St.

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

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Receipt by new subscribe," of the first copy of RADIOWORLD mailed to them after sending In their order Isautomatic acknowledgment of their subscription order.Changes of address ehould be received at this office twoweeks before date of publication. Always give old address:also state whether subscription Is new or s renewal.

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1 Page. 754"x11" 482 lines $300.00% Page, 7 Vs"s5%" 531 lines 150.003h Page. 854" D. C. 291 lines 150.00Si Page. 45i" D. C. 115 linee 75.001 Column, 3,A"s11" 104 line. 100.001 Inch 10.00

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

4 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 29, 1922, atthe Port OM. at New York. N. Y., under the Act ofMarch 3. 1879.

MARCH 20, 1926

Roemer, of ZenithDenies Job Change

The following letter was received byRADIO WORLD from H. H. Roemer, directorof sales promotion, Zenith Radio Corp.,Chicago:

"An article appeared in a magazinestating that I had severed connectionswith Zenith Radio Corporation and gonewith some Bridgeport concern. Such areport is erroneous and absolutely with-out foundation. Publishers printing suchmatter as news certainly should secureconfirmation before placing a man in theposition this publication has placed me.I shall consider it a personal favor if youwill run in the first issue, following re-ceipt of this letter, a denial of the report."

The magazine he refers to was notRADIO WORLD.

HEAR JOHN F. RIDER, contributing editor ofRADIO WORLD, broadcast every Thursday at9 p. m. from WGCP, 253 meters. D. W. May,Inc.. Newark, N. J. Mr. Rider diacueses radioproblems.

Standard DefinitionsCompiled by Experts

Definitions of intense interest to radioexperimenters are contained in the In-stitute of Radio Engineers' Report of theCommittee on Standardization for 1926.This contains definitions of terms, stand-ard and graphical symbols used in RadioEngineering. The report is copyright,1926, by the Institute of Radio Engineers(Inc.). The following excerpts are re-printed by special permission of the copy-right owner:

RECEIVINGReceiving Set (Receiver)-A device for

converting radio waves into perceptiblesignals.

Monitoring Receiver-A receiver ar-ranged to enable an operator to check theoperation of a transmitting set.

Heterodyne Reception-The process ofreceiving radio waves by combining thereceived current with locally generatedalternating current. The locally gener-ated frequency is commonly differentfrom the frequency of the received cur-rent, thus producing beats. This is calledbeat reception.

Self -Heterodyne Reception (AutodyneReception)-A system of heterodyne re-ception through the use of a device whichis both an oscillator and a detector.

Homodyne Reception-The process ofdetecting a wave by the aid of a locallygenerated wave of carrier frequency.(Sometimes called zero -beat reception).

Super -Heterodyne Reception -Amethod of reception in which the receivedcurrent is combined with the current froma local oscillator and converted into cur-rent of an intermediate frequency whichis then amplified and detected to repro-duce the original signal wave.

Intermediate Frequency-A frequencyof a magnitude between that of the car-rier employed in radio transmission andthe frequency of modulation, and towhich the carrier is converted in thesuper -heterodyne process of reception.

Reflex Circuit-An arrangement inwhich one or more amplifiers are used,

each to amplify the signal both beforeanti after detection.

Tuning-Primarily, the adjustment of acircuit or circuits to resonance. Use alsoto mean the adjustment of a circuit orsystem to secure maximum transmissionof a desired signal.

Sensitivity-The degree to which aradio receiving set responds to signals ofthe frequency to which it is tuned.

Selectivity-The degree to which aradio receiving set is capable of differ-entiating between signals of different fre-quencies.

Detector-That portion of the receivingapparatus which, connected to a circuitcarrying currents of radio frequency, andin conjunction with a self-contained orseparate indicator, translates the radio -frequency power into a form suitable foroperation of the indicator. This transla-tion may be effected either by the con-version of the radio -frequency power, orby means of the control of local power.The indicator may be a telephone receiver,relaying device, tape recorder, and so on.

The most common type of detector is avacuum tube operated on a non-linearportion of its characteristic curve, there-by converting a modulated radio -fre-quency current into a modulated directcurrent.

A tube which operates similarly to adetect tube, but the output of whichdoes not operate an indicator, may prop-erly be called a frequency convertingtube.

Telephone Receiver-An electrically op-erated device designed to produce soundwaves which correspond to the signal cur-rent actuating it.

Loud Speaker-A telephone receiverdesigned to produce sound of sufficientlylarge volume to be heard at a substantialdistance.

Interference-Confusion of receptiondue to strays, undesired signals or othercauses; also that which produces the con-fusion.

House Clashes OverThe Monopoly Clause

WASHINGTON.The White bill to be considered by the

House will not be encumbered by Section4, which was considered so objectionableby Mr. White and most of the radiomanufacturers and broadcasters. Section4 was the provision making it unlawfulto transport in interstate commerce radioapparatus or tubes upon which there wererestrictions as to use.

As originally reported by the Housecommittee, the White bill contained theanti -monopoly clause. Mr. White wasopposed to the clause on the ground thatit conflicted with the patent laws. There-fore, Mr. White introduced a new bill,similar to the bill reported out by theHouse committee, with the exception thatthe anti -monopoly clause was eliminated.The new White bill was sent to committeeand immediately reported back to theHouse.

An effort will be made by a number ofHouse members to have the anti -monopolyclause reinserted into the bill. A proposalwill also be offered to establish a newcommission with authority to take overradio in its entirety from the Department

of Commerce. This commission would besomewhat along the lines of the InterstateCommerce Commission which has juris-diction over the railroads.

Heading these proposals will be Rep. E.L. Davis, of Tennessee. Judge Davis isthoroughly convinced that certain inter-ests are trying to get a strangle hold onradio and that they will succeed unlessdrastic steps are taken immediately. JudgeDavis is the ranking Democrat on theHouse committee which considered theWhite bill. It was at his instance thatsection four was added to the measure. Ina long minority report, Judge Davis calledattention to the Federal Trade Commis-sion report on the alleged radio monopoly,and quoted some of the witnesses appear-ing before the committee as bearing outhis contention.

WFBI NOW WGAMWASHINGTON.

The call signal of WFBI, Camden, hasbeen changed to WGAM. The station isowned by the Galvin Radio Supply Corn-.pany and uses 250 watts power.


Metal Panel

VOLUME is controlled by a switch in this 6 -tube set, which has four stages of resistance -coupled audio.

Panel View of the Set

Factory SetsA weekly department for the

Owners and Prospective Pur-chasers of Manufactured Receivers.Address questions to Factory SetEditor, RADIO WORLD, 145 West45th St., N. Y. C.

THE 6 -tube Airway Receiver, the cir-cuit diagram, rear view and front

panel of which are illustrated on this page,utilizes resistance coupled audio frequencyamplification for supreme tonal quality.So that utmost volume will be obtainedon distant stations there is a fourth stageof audio, a switch enabling one to utilizethe three or four stages, without removalof the speaker plug.

On the radio side the set has a stageof tuned radio frequency amplificationahead of a non -regenerative detector. Theantenna coil is comparatively large, andit is tapped, so that best reception for anygiven aerial will be achieved, and also sothat utmost sensitivity may be enjoyed indistance reception, when one settng ofthe tap may function better than another.The coils used are low -loss radio -fre-quency transformers of efficient design,the primaries being inside the secondaries.The set tunes without squealing, due tothe coil construction and position, and tothe use of high-grade parts throughout.The set is marketed in a handsome cabinetand is sturdily constructed and packed.It is very easy to tune, due to the pres-ence of only two dials, and affords a re-markably enjoyable quality.

Interesting Definitions

WHAT DOES micro mean?Micro is a prefix meaning one millionth.

That is, a microfarad is one millionth ofa farad.

WHAT DOES milli mean?Milli is a prefix meaning one thousandth.

That is, a milliampere is one thousandthof an ampere.

THE REAR VIEW of the set. Note that the coils are mounted at an angle.

What Type of ProgramBest Suits Your Likes?

The canvass conducted by RADIO WORLDto discover what its readers prefer in pro-grams is nearing its end. So far sym-phonic concerts are preferred and jazz isin fifth place. Readers who ballot willbe helping themselves to get what they

want, because stations are co-operatingand some may frame their programs onthe basis of the tabulated result.

Fill out and mail in to the ProgramEditor the following coupon and mailtoday.

Program Editor, RADIO WORLD, 145 West 45th Street, New York City:My preference for entertainment and instruction on the radio is as follow:, tht

numbers next to the listed items representing the order of preference:

Grand opera Ringside Football gameJazz Orchestra boxing report Hockey matchTalk Classical instru. RecitationState subject mental solo Musical comedy

of talk here State kind here (stage)Classical vocal Jazz songs Short play

solo vocal (drama)State kind here Waltz (orchestral) Short playMusical saw Symphony concert (comedy)Vocal duet Instrumental duet Banquets, withVocal trio Instrumental trio speechesVocal quartet Instrumental quartet SermonsOld-time music Brass quartet Market reportsBand concerts Bedtime story Weather reportWorld Topics Baseball game Organ recital

If you particularly dislike any of the above listed offerings, write "No" on thedotted line.Other offerings (not listed above)

Remarks (if any)

Fill out andmail thiscoupon today!

NameAddressCity State


Literature Wanted THE RADIO TRADETHE eases of readers of RADIO WORLD

who 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 WORLD145 West 45th St., N. Y. City.

I desire to receive radio literature.Name

City or townState .

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

His Nita*His Address

Walter L. Sudbrook, 2913 Walnut. Kansas City,MHo.

arry Finger, P. Q. Box 9, City Hall Sta..N. Y. City, N. Y.D. J. Doherty, 5 Emmett Terrace, Revere. Mass.J. C. Crow, Rt. 6, Box 215, Oklahoma City, Okla.A. Elvin. 3618 Cambridge St., Des Moines, Ia.John R. Vollmer. 1034 Brock St., Ashland. Penn.Geo. Schrier, 461 McLaughlin Ave., Muskegon,

Mich.Ernest Seitzler, 1618 Michigan Ave., Dallas.Tex.John C. Clifford. 4925 Broad St., Pittsburgh. Pa.L. Colombo, 2326 N. 72nd Court, Elmwood Park.

Walter H. Kozaczko, Jr., Box 66, Uxbridge,Mass.S. J. Fluke, Clark Mills. N. Y.T. J Welch, Box 265, Syracuse, N. Y.L C. Higgason, 303, The Temple.Frank Finn. 448 Maple Ave., Elizabeth, N. J.Lloyd Blue, 415 Stone St.. Georgetown, Ill.R. E. Rarngran, 2568 Marcy St., Omaha, Nebr.0. L. Lezotte, 6037 Normal Blvd., Chicago. III.George H. Schroff, 308 E. 155th St., N. Y. City.

N. Y.T. Weiss, 102 Park St., Millvale Boro, Pitts-

burgh, Pa.G. E. Faulk. Island Radio Shop, 636 Virginia

Ave., Butler, Penn.R. A. Cabot, 3442.42nd St., Long Island, N. Y.Robert Dagger, 1327 Amsterdam Ave., 14. Y. C.Carl G. Andrews, Tladalin, N. Y.R. E. Graeff, Box 117. Ambler, Pa.Chas. Boehnker, 2843 Brant Ave., Portsmouth,

Ohio.Rudolf Sucky, Box 88, Blaine, 0.G. M. Geltz, Rossford. 0.C. R. Cook, 104 N. Stafford Ave., Richmond,

Va.Ernest Williams. 552 Word St., Niles. 0.H. J. Kappus, P. 0. Box 777, Shawnee, Okla.J. Wilson, Nacogdoches, Tex.Herbert Addison, 86 Hawthorne Ave., Newark,

N. J.Schuessler, 376 E. 155th St., N. Y. City,

Raymond Arnett, 1316 Terrill St., Chester, Pa.G. A. Ashland, Douglas Steam Laundry. Doug-

las. Wyo.Wm. Lee Dale. Box 269. Versailles. Ky.R. C. Gustin, 108 N. Kanthus St., Tulsa, Okla.W. H. Kilbourne. Box 1844. Tulsa, Okla.Wm. F. Gaetz & Son, 606 W. Perry St., 0.

(Dealer).The Little Radio Shop. 9 Henry St.. Portland,

Me. (Dealer).S. G. Reynolds & Ca, Sanitaiia Springs, N. Y.

(Dealer).Irving B. Kunz, 3419a Pestalozzi St.. St. Louis,

Mo.George H. Male, 1843 East 25th St., Cleveland.

Ohio.Hal De Lamatre, Kimfalls, 0.Arnold Walder, 1902 Waveland Ave.. Chicago,

Ill. (Dealer).

The DC -112 Power TubeThe DC -112 tube made by the Conne-

wey Electric Laboratories, Hoboken, N.J., has an amplification constant of eightand an exceedingly low plate impedance.Its characteristics are such that it canhandle large power surges with completeease. The result is a rich, heavy flow ofpower from filament to plate and thus tothe loud speaker. That is why in the finalaudio socket you get a fullness of volumeand richness of tone. As a detector alsothe DC -112 delivers fuller signals. Whenproperly biased it is excellent in the radiofrequency sockets.

The following is the C battery table:Plate Volts Negative Bias

90 611214 71,11

135 9157 10%

17,500 More Sets UsedThis Year In Milwaukee

Factory -Made ReceiversIncrease 18 Per Cent.,While Home -Made Pro-ducts Show Proportion-ate Loss.

A big increase in the listening audiencein Greater Milwaukee, meaning increasein the number of radio receiving sets inMilwaukee homes, is indicated by figuresobtained in the preliminary studies of theMerchandising and Research Bureau of"The Milwaukee Journal."

The number of receiving sets grewduring 1925 from a total of 23,000 to 40,-000. More than 17,500 Greater Mil-waukee families "went in for radio" dur-ing the year. Twenty thousand sets werepurchased and 8,000 were built or as-sembled by the owner. This indicatesthat approximately 11,000 sets were dis-carded, traded in or rebuilt, most of these.of course, being crystal and one -tube af-fairs.

18 Per Cent More Factory SetsThe percentage of Greater Milwaukee

families owning a purchased set as ofJanuary 15, 1926, in comparison with thosewho built their own set, shows an increaseof 18 per cent, while those in the latterclass show a proportionate loss. Be-cause of the increased number of familiesin the city this year as against last year,however, the total number of home-madesets is a triflle larger than it was lastyear. Of the home-made sets, 29 per centwere made from standard kits, or accord-ing to standard circuit. Crystal sets areon the decline, and this year will probablybe the last of this type for, while thepercentage of the total number of radioset owners who owned a crystal set onJanuary 15, 1925 was 8, the percentagethis year is only 1.7. The majority ofcrystal sets, as was the case last year,fall under the heading of home-made.

Radio sets in combination with phono-graphs have not as yet taken a great holdin this market. Only 5.5 per cent of allthe families in Greater Milwaukee whoowned a radio set on January 15, 1926.owned a set which was in combinationwith a phonograph.

Freshman Sets Most Popular"Freshman sets have increased in pop-

ularity to first place on January 15, 1926,. "says the report. "Sets manufactured bythe Radio Corporation of America, whichwere in first place last year, take secondplace this year with Atwater -Kent third."

Five -tube sets maintain their lead, thisyear their percentage being well over 53per cent, as compared to 22 per cent ofall the sets last year. The greatest de-cline is -in three -tube sets, which droppedfrom 36 per cent of the total to 15 percent. Six -tube sets show an increase of3 per cent. The average hours of useper family per week have increased from21.2 to 27.

As to loud speakers, 67 per cent of allfamilies in Greater Milwaukee who owna radio set own a horn type; 12 per centuse the built-in speaker in connectionwith the set; 7 per cent use the cabinettype; 3.5 per cent use a phonograph at-

tachment, and 2 per cent use cones. Nineper cent do not use any loud speaker.

Battery EliminatorsAs yet, battery eliminators have not

come into great use among Greater Mil-waukee radio set owners. Forty-threeone hundredths (.43) of one per cent ofradio set owners own and use the com-bination A and B battery eliminator.Fifty-two one-hundreths (.52) of one percent of all radio set owners use an Abattery eliminator.' B battery eliminatorsare used by 3.54 per cent of all GreaterMilwaukee radio set owners.

Fifty-five and sixty-five one -hundredths(55.65) per cent of all Greater Milwaukeeradio set owners own a battery chargerOf those Greater Milwaukee radio setowners who use batteries, 79.5 per centuse the wet type, and 20.5 per cent thedry type.

In dry A batteries, Eveready leadswith 45 per cent of the total, this beinean increase of 25 per cent over last yearBurgess, which is in second place, showsan increase of 7 per cent over the totalfor last year.

Wet Battery Users DecreaseOf those owners of radio sets in

Greater Milwaukee who have occasion touse B batteries, 12.97 per cent use thewet type, and 87.03 per cent use the drytype. In the last analysis compiled for1924, the wet users represented 13.38 percent. This shows a slight decrease inthe percentage of wet B battery users.In the dry type, Eveready again leadswith 46.30 per cent of the total, an in-crease of 8 per cent over last year. Bur-gess is second with 23.91 per cent of thetotal, an approximate loss over last yearof 10 per cent.

Analyzing the type of antennas usedby Greater Milwaukee radio fans, the in-vestigators found an increase of 14 percent in the inside type, with a corres-ponding loss in the outside type; loopsshowing a very small decrease. Fiftyper cent of all antennae are inside; fifty-five per cent outside; and 7.6 per centloops. The fact that the percentage ex-ceeds a total of 100 is due to a numberof radio owners using more than onetype.

Business OpportunitiesRadio and Electrical

Rates: 10 c per word; Minimum, WOO; Cashwith order

RADIO STORE, splendidly located. TimesSquare section; new, up-to-date furnishings andfixtures; sets and accessories only; franchisesinclude R. C. A., Stromberg-Carlson, AtwaterKent; present volume of business satisfactorybut can be greatly increased; rent under 5600monthly; excellent lease; other interests compelowner to sacrifice for immediate sale; terms ar-ranged. Box 1, RADIO WORLD.

MANUFACTURING MACHINE SHOP, locatedin Brooklyn, having large equipment, is availablefor immediate production on contracts, coveringlarge and small quantities, will consider manu-facturing complete patented unit having merit:25,000 square feet pf space available. Duplex Con-denser and Radio Corp., 36 Flatbush Ave. Exten-sion, Brooklyn, N. Y. Phone, Cumberland MOO.

RADIO STORE., battery station. fastest grow-ing section Long Island, block from subway sta-tion; established two years; lease runs twoyears. can renew; stock inventory $3,0001 willsacrifice; good reason; battery charging paysall overhead. 379 Broadway, Astoria. PhoneAstoria 3863.

ELECTRICAL BUSINESS, well established; ex-cellent location; long lease; reasonable. Boat 2,RADIO WORLD.


BRING IN EUROPEON A

Victoreen "Super"

The Heart of the CircuitEach

4. No. 170 R.F. Transformers at $7.00No. 150 Coupling Unit @ $5.50

You can secure these and all other pansnecessary from your dealer.Victoreen Air Core Transformers are morethan matched-they are actually tuned toguaranteed precision of 1/3 of 1%.Ask your dealer for a free folder on hook-upof Victoreen 'Super" or write directly to us.This folder answers all questions about theVictoreen.

The George W. Walker Co.6515 Carnegie Ave., Cleveland, Ohio

Braucher in prtn,

NEW CORPORATIONSDunst Electric Service Corp., N. Y. City, realty

radio fixtures. $5,000; B. Milstein, S. and S. Dunst.(Atty., S. Fisher, 291 Bway, N. Y. City).

Hoffman -Green Radio Corp., N. Y. City, $10,-000; W. Hoffman, G. Green, R. Rosenthal. (Atty.,M. A. Vogel, 1431 Broadway. N. Y. City).

General Service. Stations. N. Y. City. wirelessapparatus. $10,000; J. H. Dempsey, M. C. Rosen-thal. F. Feldman. (Atty., E. Petigor, 233 West42cl St.. N. Y. City).

A. H. Lynch, radio, N. Y. City. 1,000 common,

TERMINALS LOCK ALL CIRCUIT CON-NECTIONS PERMANENTLY; SAVE TIMEAND LABOR:ISN'T THAT

GOOD?H TEY ARE NEATER.

27 Hammett Road Roslindale.Maes

ACCUSTI-CONESpEA-1,-4A

From

FactouDirect to -You

10 -Inch. full aim, full floating cone. Wouldcost $30. In a retell store. You save bybuying direct. It Is superior to any speakermade. Try It In your home; if not satiafied,return end get money back.

Accusti-Cone Laboratories96 Church St. NI, York

no par; A. H. Lynch, R. A. Sayres, L. R. Beardsley. (Atty., F. J. Knorr, Albany, N. Y.)

Akradyne Radio Corp., N. Y,' City, $20,000: M.Bellfort, M. Montag, M. M. Simon. (Attys..Greenspan & Morris, 305 Broadway. N. Y. City).

Radio Shop 2836 Broadway. N. Y, City, $10,000;C. ,Essinger, W. Surnamer. (Atty., P. Abrahams.552 5th Ave., N. Y. City).

Uco Radio Corp., Utica, N. Y. $50,000; C. A.Schmidt, F. C. Hopkins, O. J. McKeown. (Attys..Dunniore, Ferris & Dewey. Utica, N. Y.)

So -Low Radio Corp.. Paterson, N. J.. manufac-ture, $25,000; Frieda Solow, Paterson, N. I., MaxGoldberg, Newark, N. J. (Atty., W. J. Broody,Paterson N. J.),

Radioette Corp., Queens, N. Y., radio, 500shares, $100 each; 2,800 common, no par; A. Piel,J. M. McCaffery, M. M. H. Ravel. (Atty., A. L.Marino.. 20 Nassau St., N. Y. City).

Smith & Cowper, Lynbrook, L. Is., N. Y. radioaccessories. 510,000; W. C. Cowper. L. Skinner,A. R. Smith. (Attys., Buchdahl, Males & Lempel.276 5th Ave., N. Y. City).Petite Radio Corp., of New York, N. Y. City,30,000 common, no par; L R. Seidel. H. B. Mat-theson, G. J. Horvitz. (Attys., Bassett, Thomp-son & Gilpatric, 233 Broadway, N. Y. City). '

Bailey's Music and Radio Shop, N. Y City,$1,000; E. McCarthy, A. L. Williams. (Atty., D.B. McNamara, Jr., 5th Ave. and 9th St.. N. Y.City).

NAME CHANGESKardon Radio Corp., N. Y. City, to Diva Radio

Corp.Niagara Battory Corp., Niagara Falls. N. Y.. toC. S. Betting,.

CAPITAL INCREASESStromberg.Carlson Telephone Mfg. Co., Ro-

chester. N. Y., 80,000 shares. $25 each, to 320,000common. no par.

Facts on ChargingWhen charging two 22 volt (small

type) lead cell storage batteries, connecta 25 -watt lamp in series with the negativeterminal of the battery and the line.This applies to the use of a DC lineonly. For an AC line, some form ofrectifier must be employed. If the 2 -

ampere charger is employed, then con-nect three 22% volt (small type) batteriesin parallel.

Chosen for Performance

TYPO 271M. F. Transformer

Price. $5.00

Type 331Tuned Transformer

Prior. $5.00

Type 349UK Tube Socket

Price 505

The performance of a radio receivingset depends primarily upon two things,an efficient circuit and the use of goodparts.

Wherever you find a popular circuityou will invariably find General Radioparts.

General Radio parts are built to exactinglaboratory standards by a company whichhas contributed more in scientific apparatusfor radio research than any other one com-pany in the history of radio.

To insure maximum performance fromyour set select a reliable circuit-then buildit carefully with General Radio parts.

GENERAL RADIO CO.CAMBRIDGE 39 MASS.

TyPO 247-FVariable Condenser

Price. $4.00

/1111111111111k

Typo 214-A20 Ohm Rheostat

Price. $2.25

Type 3016 Ohm Rheostat

Price. $1.25

INSTRUMENTS"Behind the Panels of Better Built Sets"

7-1 RADIO WORLD March 20. 1926

The Ways of a Magnet;2 Processes Explained

A natural magnet is a substance, whichif it is dipped into filings of iron, thefilings will adhere to the magnet, or if aportion of the substance is suspended bya cotton or silk thread, it will place itselfwith its longer axis to the north and thesouth direction. The magnet is usuallymagnetic iron ore and is found in theearth in the form of black oxide of iron.

Now if a rod of steel is brought nearto a piece of this magnetic iron ore, or isrubbed with the ore, the steel bar becomesmagnetized. If the bar is of a very hardsteel, this effect persists, even after therod is taken away. The steel rod is thencalled a permanent magnet. Usuallythese pieces of steel are made in theshape of horseshoes.

There is another way in which a sub -

FOR CLEAR, QUIET "B" POWER

RADIOStorage "B" Battery

as votes Lasts Indefinitely-Pays for ItselfE001.011 and performance unheard of before. Recharged et a ir.

Itrroirdtesaliligtedl""ar 13=cft111.2:11,?A°:;,..8,":Eo

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tn:gag Pea. tdle Laboratories. Pop. hot. Slender& Radio NewsItoti 122166ei."&i.,-.1,,tr,r1Tr-r-"-thrxd

jars. HOSIT7 rug call...tn. "O'rSor soon. todsly'!.SEND NO MONEY IV:dtra trw`lri`.1% rg7.4

received. Extr Offer: 0 batteri& in series AM &Rel. iln50 1-01'exis emman after exemining batteries. 6 per cent discount for aawith order. Mall your order new!WORLD BATTERY COMPANY

1219 So. Wabash Ave.. Dept. 82 Chicago. IRMake& of Me Famous World Redio "A'. Storage Boner,Priew 6 -volt. /0 AU c0

m.rty..A ante Sold 171RubUw, C45,11,; ar.my. "14.00.A

World6TORAGE BATTERIESkV,

Set your Radio Dial, et 210meters for the ne 1000

n'ttiet7TYSSta". itbatteryo

viemh ter announcements.

Tonic forsick tubes

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110 welts

$4.50and thiscoupon

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OCKWLTube Reviver

Renew all of your tubes for lestthan the cost of two. Seed eamoney. Reviver will be mailedC. 0. D. to thaw sending 'wpmSatisfaction. or money bad.

BRINGS QUICK RELIEF

International Resistance Co.,Pen, Bles.. Philedelohle.

Plasm mod me by OmDeld PanelPoet, co. o.. one HOCKIT TubeReviver, trite as noted. I will oarpostman 14.60-with the understand-las that money will be returned lif Iem sot entirely settafisd.

Cf001 eate we

201.6%

189

NamAddress

City Mate

stance can be given magnetizing prop-erties and that is by passing a currentthrough a coil of insulated wire, which isplaced over a rod. This rod is usuallymade of soft iron. The magnet has thisproperty only as long as the current ispassing through.

RESULTS EDITOR:

I have been a radio bug since my periodin the army. I have tried the hookups

K B 8(Non -Regenerative Browning -Drake)

NO MORE BLOOPERS!That's the new Golden Rule of radio.Your neighbors won't tear their hairwhen you tune in a KB -8, because itis non -regenerative. And you will getthe quality of reception which onlya non -regenerative set can produce.THE KB -8 WILL BRING IN AT FULLVOLUME ANYTHING THAT ASUPER -SENSITIVE SET CAN RE-CEIVE WITH GOOD QUALITY.

DATAPRINTSfor SET BUILDERS $1"Detailed description and 12 photo-graphs are given in Radio EngineeringMagazine, March issue. Send 20c instamps, or $2.00 for a year's subscrip-tion. Radio Engineering is not soldon newsstands.

RADIO DEALERSThe KB -8 Is the very latest thing inBrowning -Drake development. Data -prints can be bought at full discount.Sell them to move parts. It is non -regenerative.

Dataprints Sold in Individual Tubes

M. B. SLEEPER, Inc.TECHNICAL PUBLISHER

V-52 Vanderbilt Ave.Vanderbilt -4996.

published in RADIO Wolux and have faredwell with all of them. I built the mostpopular of circuits, the Diamond of theAir, and have had wonderful results.There is a local station five blocks awayfrom me and it is not difficult to tune itout. Chicago stations can be brought inwith great volume with this local going.A home-made loop is used as the collectorof energy. I also wound my own coils,which are of the basket weave type.

ROBERT HAMILTON,Preston Hotel, Dallas, Tex.

The Daven Super -Amplifierfor volume and tone quality

3 STAGES RESISTANCE COUPLEDECONOMICAL DISTORTIONLESS

Easily added to any setSaves Several Hours' Assembly

For Sale by All Good Dealer,

IN THE WEST

it's"RADIO"For Seven Years the BestPractical Radio Magazine.

A FreeSample Copy

for the askingPACIFIC RADIO PUB. CO.Pacific Bldg. San Francisco

TWO -FOR -ONE SUBSCRIPTION OFFERRadio World has made arrangements-To offer year's subscrtpyon FREE for any on. al the following publIcation with emsyear's subscription for RADIO WORLD,-POPULAR RADIO or -RADIO JOURNAL or-RADIO BROADCAST or -RADIO Man Francisco) or-SCIENCE AND INVENTION or -RADIO AGE-RADIO NEWS -COLLIER'S-RADIO DEALER or -BOYS' LIFEThis is the way to get two publications-for the price of own-Send KM today for RADIO WORLD-for one year (regular price-for 52 numbers)-and select any one of the other-nixie publications far twelve months.

-Add $IM a year axtre for-Canadian or Foreign Postage.-Present RADIO WORLD subscribers-can take advantage of this afar by-extending subscriptions one year-if they send renewals NOW.

RAL)10 WORLD'S Special Two -For -Price -of -One SUBSCRIPTION BLANKRADIO WORLD. 145 West 45th St.. N. Y. at,,Enclosed find $6.00, for which send me RADIO WORLD for twelve months (52 number.), begin-ning

a and also, without additional cost, PopularRadio, or Radio Broadcast, Radio News, or Science and Invention, or Radio Dealer, or Radio(San Francisco), Boys' Life, or Radio Journal, Collie?. or Radio Age (or $10.00 for two yearlysubscriptions).

Indicate if renewaLOffer Good UntilApril 7.

Name

Street Address,

City and State


Things Unsaid MakeAnnouncer, Says Hay

George Dewey Hay, known to the radiofans of the country as "The Solemn OldJudge," now director of radio stationWSM, Nashville, Tennessee, won his way

RIGHT TO THE POINT!Erstreme accuracy of dial reading is assuredwhen Y.0 me EUREKA DIALPOINTERS! Tuning In distance is

edPolished Nickel or Gilt, % or %.1

C. W. BUTTS, lee.40 Heddea Place East Orange.

Dealer InquiriesSolicited.

THE VICTOREENHow to build this 8 -tube Super -

Heterodyne described in February20, 27, March 6 and 13 issues ofRADIO WORLD. Send 60c for allfour copies, including FREE blue-print. Send $6 for year's subscrip-tion and get these four copies andblueprint FREE I

RADIO WORLD145 W. 95th St. New York City

to fame and popularity not only throughhis original ideas of broadcasting andnovel stunts, but because of strict adher-ence to his radio slogan, "Never Fail ToBroadcast A Smile." Mr. Hay is nowliving up to his reputation at WSM, wherehe is guiding genius of the station as wellas chief announcer, for "The Solemn OldJudge" still keeps in touch with his largeradio following over the microphone, in

GEM TUBEA Guaranteed Radio Tube

Within Reach of AllEvery tube guaranteed. A tubefor a dollar of 92 nine. Atrial order will convince you asIt has thousands of other..Send your orders at once.Orders gent C.O.D. parcel post.Type.. I99A

TN:::2: $1.00TyPe..20IA(with standard base) EACHDealers. Write for Discounts.

GEM TUBE CO.Dent. W.. 200 Bray. N. Y. C.220 So. State St.. Chicago. 111.

Lafayette Bldg.. Detroit. Mich.

for the Super de Luxe

9

-right on thedial itself -your record ofstation settings

SCARCELY a single well -designed new circuit .

today . . but uses MAR-CO dials. On the Super-heterodyne de Luxe, de-scribed in this issue by J. E.Anderson, two MAR -COdials provide the searching

dial -action that is one of thefeatures of this set. PutMAR -CO dials on your ownset tonight. To put it off,is to miss the best your setcan do. Martin CopelandCompany, Providence, NewYork, Chicago.

Hair-trigger CO Micrometer -like actionresponse

DIALS aThe 1926 model tuning control

CHANGES OF ADDRESSshould be sent to Subscription Department at least two weeks in advanceof publication in order to insure early and proper attention. RADIOWORLD'S subscription list is so large that it is necessary that changes besent in as requested. Address, Subscription Department, RADIO WORLD,145 W. 45th St., New York.

addition to directing the activities ofWSM.

"It isn't so much what the announcersays into the mike," declares Mr. Hay, "aswhat he doesn't say, that counts towardpopularity." "The Solenin Old Judge" isa newspaperman, who recognizes the im-portance of the radio as a news medium;a humorist who appreciates a joke when itis on himself as well as when it is on theother fellow, and who understands with-out being cynical that people and theirdoings are always amusing; a psycholo-gist who knows the importance of puttinghimself in a position of middleman be-tween the artist and the listener.

Mr. Hay was born in Attica, Indiana,and spent ten years of his life in theHoosier town. Before his debut as aradio announcer he was a newspaper re-porter and feature writer on the Mem-phis Commercial Appeal. He broughtevery bit of this experience to his radiowork and regards radio as practically anew kind of newspaper, with a circula-tion running into the millions., "The an-nouncer must have a nose for news," hesays. "Radio is the world's newspaperand the announcers are its reporters."

"The Solemn Old Judge" took his first'radio steps as chief announcer for WMC.

Results Editor:I have built the 4 -tube Diamond of the

Air, as described by Herman Bernard inthe Jan. 23 issue of RADIO WORLD. I havefound this set to be wonderful. I havebeen able to get loud speaker receptionfrom stations WOAI, WOAW, WHO,KFUO, KPRC, KDKA, KFKX, KDKA,KFKX, WJZ, WRC, WGN, KPRC,WSAI, WLW, WLS, WJAX, WSB,WSMB, WAAM and PWX. I mightmention that the RFT is wound on an oldstyle talking machine cylinder or record.

G. McCHESNEY,203% Park Place,

Montgomery, Ala.

DISTANCE AND VOLUME

AT YOUR COMMANDBuild a 5 -Tube Tuned Ra- $7dio-Frequency Set, Usingthe Streamline Kit

.50

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

basketweave coils, 3 mountings.Above, with 3 Bruno Slo-Moshen VernierBakelite Dials $12.30

Streamline Condensers.00025 mfd.....$2.00 % Straight.00035 mid..... 2-23 Line

Frequency

C'T'^-t." A W!!IrE. TI) nim yr%AlLitkiX1141.1.1 Le ru-waur LO.

7.3 FULIVN STREET.New York City

Have you seen the Clinical Study ofLow -Loss Coils, covered by the Bureauof Standards, that appeared in our Jan.16 issue? Send 15c for a copy.


The Ways of a Magnet;2 Processes Explained

A natural magnet is a substance, whichif it is dipped into filings of iron, thefilings will adhere to the magnet, or if aportion of the substance is suspended bya cotton or silk thread, it will place itselfwith its longer axis to the north and thesouth direction. The magnet is usuallymagnetic iron ore and is found in theearth in the form of black oxide of iron.

Now if a rod of steel is brought nearto a piece of this magnetic iron ore, or isrubbed with the ore, the steel bar becomesmagnetized. If the bar is of a very hardsteel, this effect persists, even after therod is taken away. The steel rod is thencalled a permanent magnet. Usuallythese pieces of steel are made in theshape of horseshoes.

There is another way in which a sub -

FOR CLEAR, QUIET "B" POWER

RADIOStorage "B" Battery

11,;:gs. Lasts Indefinitely-Pays for ItselfEconomy and performance unheard of before. Rachar¢r aat e neirliuiettgiursttan9r t117:gdZlir include4aPord!:dlion!nbziatru-,ies. Pop. Sol. Ins t. Standuds Radio ViersSofa Rubb, Cr;ratoin I n:ifrire'teIne'r ZIT= Iratt:q=heavy els, jare. nee, rugged plate.. Order you, today!.SEND NO MONEY t"1",;.>=11:?,`"4`.1.,,i

is rec.:Ivo& Extra otter: 4 batteries in eeries tan voltst!'ainiaordersulth ntrr'" per discount

WORLD BATTERY COMPANY1219 So. Wabash Ave., Dept 82 Chicago.h/oPers lhe Famous World Rad.° "A Storapo Batter,

otPekes: 100 AMP. $11.25. 110 Am, tlr rb l40Anay 3,400.AU rouippod triin Said

WorldSTORAGE BATTERIESIEWIA,'WF4F0W6N,W.)5..iouSK6

itett:YTIRadio t!)1V: w tat250

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Tonic forsick tubes

fr®147socket,A.C. orD.C,

DO volts

$4.50and thiscoupon

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for201-A

190

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OCKtiTube Reviver

Renew all of your tubes for tenthan the met of two. Send romoney. Reviver will be mailedO. 0. D. to those minding Maim.Satisfaction. or money heck.

BRINGS QUICK RELIEF

International Resistance Co..Perry Bldg. Philadelphia.

Please send me by prepaid ParcelPost. C.O.D.. one SOCKET TubeDeriver. UN ai noted. I will 1.7DOgtraall $i.64-with the understand -ins that money will be returned ifma not entirely satisfied.Name

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City Mato

Crone sotgas

201.Alag

stance can be given magnetizing prop-erties and that is by passing a currentthrough a coil of insulated wire, which isplaced over a rod. This rod is usuallymade of soft iron. The magnet has thisproperty only as long as the current ispassing through.

RESULTS EDITOR:

I have been a radio bug since my periodin the army. I have tried the hookups

K B 8(Non -Regenerative Browning -Drake)

NO MORE BLOOPERS!That's the new Golden Rule of radio.Your neighbors won't tear their hairwhen you tune in a KB -8, because itis non -regenerative. And you will getthe quality of reception which onlya non -regenerative set can produce.THE KB -8 WILL BRING IN AT FULLVOLUME ANYTHING THAT ASUPER -SENSITIVE SET CAN RE-CEIVE WITH GOOD QUALITY.

DATAPRINTSfor SET BUILDERS $1.00

Detailed description and 12 photo-graphs are given in Radio EngineeringMagazine, March issue. Send 20c instamps, or $2.00 for a year's subscrip-tion. Radio Engineering is not soldon newsstands.

RADIO DEALERSThe 1{13-8 is the very latest thing inBrowning -Drake development. Data -prints can be bought at full discount.Sell them to move parts. It is non -regenerative.

Dataprints Sold in Individual Tubes

M. B. SLEEPER, Inc.TECHNICAL PUBLISHER

V-52 Vanderbilt Ave.Vanderbilt -4996.

published in RADIO WORLD and have faredwell with all of them. I built the mostpopular of circuits, the Diamond of theAir, and have had wonderful results.There is a local station five blocks awayfrom me and it is not difficult to tune itout. Chicago stations can be brought inwith great volume with this local going.A home-made loop is used as the collectorof energy. I also wound my own coils,which are of the basket weave type.

ROBERT HAMILTON,Preston Hotel, Dallas, Tex.

The Daven Super -Amplifierfor volume and tone quality

3 STAGES RESISTANCE COUPLEDECONOMICAL DISTORTIONLESS

Easily added to any setSaves Several Hours' Assembly

For Save by All Good Dealer..

IN THE WEST

ies"RADIO"For Seven Years the BestPractical Radio Magazine.

A FreeSample Copy

for the askingPACIFIC RADIO PUB. CO.Pacific Bldg. San Francisco

TWO -FOR -ONE SUBSCRIPTION OFFER¶t.xdio World has made arrangements-To offer a year's subscription FREE for any one of tie following publications with assyear's subscription for RADIO WORLD'-POPULAR RADIO or-RADIO BROADCAST or-SCIENCE AND INVENTION or

-RADIO NEWS-RADIO DEALER or

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

This is the way to get two publications-for the price of oast-Send $0.00 today for RADIO WORLD-for one year (regular prime-for 52 numbers)-and select any one of the other-nine publications for twelve months.

-Add $1.00 year extra for-Canadian or Foreign Postage.-Present RADIO WORLD sub...lbws-can take advantage of this offer by-extending etabacriptlons one year- they send renewals NOW.

RADIO WORLD'S Special Two -For-Price -of -One SUBSCRIPTION BLANKRADIO WORLD. 145 Weet 45th St., N. Y. City.Enclosed find $6.00, for which send me RADIO WORLD for twelve months (52 numbers), begin-ning

and also, without additional cost, PopularRadio, or Radio Broadcast, Radio News, or Science 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 UntilApril 7.

MUM

Street Address

City and State


Things Unsaid MakeAnnouncer, Says Hay

George Dewey Hay, known to the radiofans of the country as "The Solemn OldJudge," now director of radio stationWSM; Nashville, Tennessee, won his way

RIGHT TO THE POINT!Extreme accuracy of dial reading is assured

when You ase EUREKA DIALpolyrnasi Tuning in distance Is

Polished Nickel or % or IV I UVC. W. BUTTS, Inc.

40 Hadden Plate East Orange, N. J.

Dealer InquiriesSolicited.

THE VICTOREENHow to build this 8 -tube Super -

Heterodyne described in February20, 27, March 6 and 13 issues ofRADIO WORLD. Send 60c for allfour copies, including FREE blue-print. Send $6 for year's subscrip-tion and get these four copies andblueprint FREE I

RADIO WORLD145 W. 45th St. New York City

to fame and popularity not only throughhis original ideas of broadcasting andnovel stunts, but because of strict adher-ence to his radio slogan, "Never Fail ToBroadcast A Smile." Mr. Hay is nowliving up to his reputation at WSM, wherehe is guiding genius of the station as wellas chief announcer, for "The Solemn OldJudge" still keeps in touch with his largeradio following over the microphone, in

GEM TUBEA Guaranteed Radio Tube

Within Reach of AllEvery tube guaranteed. A tubefor a dollar of 92 value. Atrial order will convince you asIt has thousands of others.Send your orders at once.Orders gent C.O.D. parcel post.Type..199ATYPO..199Type ..200 $ 1.00Type ..201A(with standard base) EACHDealers, Write for Discounts.

GEM TUBE CO.Dept. W.. 200 Irway, N. Y. C.220 So. State St.. Chicago. 111.

Lafayette Bldg.. Detroit. Mich.

GEN,OFTCC100! :Pistil

201'

for the Super de Luxe

6)

9

-right on thedial itself-your record ofstation settings

SCARCELY a single well -designed new circuit .

today . . but uses MAR-CO dials. On the Super-heterodyne de Luxe, de-scribed in this issue by J. E.Anderson, two MAR -COdials provide the searching

dial -action that is one of thefeatures of this set. PutMAR -CO dials on your ownset tonight. To put it off.is to miss the best your setcan do. Martin CopelandCompany, Providence, NewYork, Chicago.

COMicrometer-Hair-triggerlike actionresponse

DIALS aThe 1926 model tuning control

CHANGES OF ADDRESSshould be sent to Subscription Department at least two weeks in advanceof publication in order to insure early and proper attention. RADIOWORLD'S subscription list is so large that it is necessary that changes besent in as requested. Address, Subscription Department, RADIO WORLD,145 W. 45th St., New York

addition to directing the activities ofWSM.

"It isn't so much what the announcersays into the mike," declares Mr. Hay, "aswhat he doesn't say, that counts towardpopularity." "The Solenin Old Judge" isa newspaperman, who recognizes the im-portance of the radio as a news medium;a humorist who appreciates a joke when itis on himself as well as when it is on theother fellow, and who understands with-out being cynical that people and theirdoings are always amusing; a psycholo-gist who knows the importance of puttinghimself in a position of middleman be-tween the artist and the listener.

Mr. Hay was born in Attica, Indiana,and spent ten years of his life in theHoosier town. Before his debut as aradio announcer he was a newspaper re-porter and feature writer on the Mem-phis Commercial Appeal. He broughtevery bit of this experience to his radiowork and regards radio as practically anew kind of newspaper, with a circula-tion running into the millions., "The an-nouncer must have a nose for news," hesays. "Radio is the world's newspaperand the announcers are its reporters."

"The Solemn Old Judge" took his firstradio steps as chief announcer for WMC.

Results Editor:I have built the 4 -tube Diamond of the

Air, as described by Herman Bernard inthe Jan. 23 issue of RADIO WORLD. I havefound this set to be wonderful. I havebeen able to get loud speaker receptionfrom stations WOAI, WOAW, WHO,KFUO, KPRC, KDKA, KFKX, KDKA,KFKX, WJZ, WRC, WGN, KPRC,WSAI, WLW, WLS, WJAX, WSB,WSMB, WAAM and PWX. I mightmention that the RFT is wound on an oldstyle talking machine cylinder or record.

G. McCHESNEY,203% Park Place,

Montgomery, Ala.

DISTANCE AND VOLUME

AT YOUR COMMAND

.50dio-Frequency Set, UsingBuild a 5 -Tube Tuned Eta- $7

the Streamline Kit

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

basketweave coils, 3 mountings.Above, with 3 Bruno Slo-Moshen VernierBakelite Dials $12.50

Streamline Condensers.00025 mfd $2.00 t Straight

.00035 mfd 2.25 Line

.0005 mfd 2.50 Frequency

STREAMLINE RkwA WRIO CO.

2.13 FULTON STREET..NewYork City

Have you seen the Clinical Study ofLow -Loss Coils, covered by the Bureauof Standards, that appeared in our Jan.16 issue? Send 15c for a copy.

26 RADIO WORLD Alai clt 20, 1920

Eveready Hour ShowsThe Art in the Irish

The average American's ideas concern-ing the typical Irishman probably runlargely to red hair, stocky build, wittytongue and ready fists. Perhaps it is be-cause the average American rather ad--mires all that sort of thing and perhapsit is-but, after all, who knows just whatis the true origin of any popular nation?

All Irishmen aren't natural born police -'men or prize fighters. There is anotherside of the true Irish nature which is justas beloved among those admirers of theIrish who are thoroughly aware of it. Itis the whimsical, the dreamy, the artistictemperahient which so often is an out-standing characteristic of the sons anddaughters of old Erin. And that was thetheme of the special St. Patrick's Eve-program for the "Eveready Hour" broad-cast Tuesday evening, March 16, throughstation WEAF, New York, and fourteen

VICTOREENSuper Heterodyne

Build the Right SetCOAST TO COAST -ON -A -LOOPNo Oscillations, Howls or Squeals

No Matching of Tubes

Range - Clarity - Selectivity -

Ease of OperationK IT-COMPLETE $64.00PARTS-SPECIAL

Including the Same Parts as Described inThis and Other Issues of Radio World.A demonstration will convince you. Tubes,batteries, cabinet and aerial, of course, notincl8ded. Packed, ready for you anywhere,with blue print instructions for connectingup.

Orders shipped same day as received.

JOHN C. RAU522-524 12th St., N. W., WASH., D. C.

RESTER Radio SOLDERIf your dealer cannot supply you

send us 25c in postage -CHICAGO SOLDER COMPANY

CHICAGO. U. S. A.

affiliated ,tations scattered through theEast and Middle West.

Last year the "Eveready Hour" pro-gram on the evening of St. Patrick's Day,portrayed the rough and ready side of theIrish nature. It told, in music and dia-logue, the story of a typical St. Patrick'snight party in a little town on the "ouldsod."

This year the program directing staff

BEAUTY -QUALITY -LOW PRICETYPE 5SS.-Tube Tuned Radio Frequency.TYPE 6856-Telte Resistance Coupled Audio TunedRed!. Frequency.

IJ your dealer cannot make immediatedelivery we will ship direct from factoryAmerican Interstate Radio Service

183 Greenwich Street. New York CityDistributors. Jobbers. Dealers. write for I PCCIIII trade term

$45

$50

MAGIC DIAL

The Newest Wonder in RadioMakes condensers that are notstraight-line frequency tune as ifthey were. MouldedBakelite. No gears, $2.50no back lash

"Bruno Slo-Moshen" VernierDial, $2

BRUNO RADIO CORP.223 Fulton Street New York City

ZILTR7I-LiOIMOSSCONDENSER

SPECIAL" CLITCASS PLATES OiSTRIBUTE THE 51A',IONS EVENLY OVER TNE 01L 510PLIFIE,TUNING CAPiCITY 0005 !AFC,

55.00PHENIX RADIO CORP.. 116-F East 25 St., N.Y.C.

of the "Eveready Group" worked forweeks to build a program of quality.

Join the HappyDiamond Family!Build This Famous 5 -Tube Set

and Know Real QualityReception !

Easy to Build, Easy to Tune!

Herman Bernard, designer of thiswonder circuit, hal written an illus-trated booklet on "How to BuildRADIO WORLD'S 1926 Model Diamondof the Air." Send 50c and get thisbooklet, including a full-sized wiringblueprint.

Outstanding Features of Set:(1) Fans, charmed by tone quality,

sensitivity and selectivity, reportspeaker reception of far -distantstations with great volume.

(2) A 2 -tube earphone set, a 5 -tubespeaker set, and a separate 3 -stage audio -amplifier for immedi-ate use with any tuner, are com-bined in one.

(3) No rheostats are used.(4) The set is inexpensive to con-

struct and maintain.

What the Circuit IsThe 1926 Diamond consists of one stageof tuned radio -frequency amplifica-tion, regenerative detector, one trans-former, coupled audio stage, and tworesistance audio stages - the utmostfrom five tubes!

Follow BernardYou can't go wrong if you follow thedirections as written by the designerhimself, as contained in the booklet.The diagrams, including blueprint,are guaranteed 100% accurate. Playsafe!Send $6 for year's subscription andget booklet and blueprint FREE

[Newsdealers or radiodealers, order the bookletswith blueprints included, inquantity, direct frontAmerican News Co. orbranches.]

RADIO WORLD145 West 45th St., New York City

EXTRA SPECIAL-NOW IN PREPARATIONThe Greatest Issue of the Year

RADIO WORLD'S FOURTH ANNIVERSARY NUMBERLast Advertising Forms Close March 24, A. M.Last Red Form March 22, A. M.

On page copy received by Monday A. M., March 22, anextra color, red (two printings), will be given in this greatanniversary issue without extra charge.

For space reservation write or phone F. S. Clark, Adver-tising Manager.

DATED APRIL 3rdRadio World's weekly subscribers have doubled sinceour Third Anniversary Number. Still advertising ratesremain the same -8240 a page, or $8 an inch, on yearlycontract. With Radio World's 100,000 weekly circulationthis advertising rate is only 82.40 per page per thousand-a lower rate than any other 100% radio interest publication.

RADIO WORLD, 145 WEST 45TH STREET, NEW YORKTelephone: Bryant 0558-0559

I


428 Seek Wavelength;Illinois First With 47CLAROSTAT

e by LEWISNERprescrib ford the TECTRON "13"ELIMINATOR. Also O.K.'d byRAYTHEON and a host ofother Nationally Known Elim-inator manufacturers. $225.American Mechanical Laboratories. Inc.285 N. 6th St. Brooklyn. N. V.

Dept. B.W.

A book of valuable radio diagrams and in-formation covering the above subjects will bemailed to you upon receipt of four cents instamps.

\\ ASHINGTON.The Department of Commerce has just

made public for the first time a list ofapplicants for new broadcasting stationsthroughout the United States. The listreveals that 428 new broadcasting stationswould soon be on the air if there werewavelengths to accommodate them.

According to officials of the Departmentof Commerce, the list indicates the greatpublicity value attached to broadcasting.At the present time there are 536 stations.

The applicants are from forty-five states

E ROMIs Specified

By LEWIS WINNER

for the TECTRONAND ALL OTHER RADIO WORLD'S

"B" ELIMINATORSWhy? Because they are "BUILT TO BE BETTER."Also FIXED MICA CONDENSERS, RESISTORS and

RESISTANCE -COUPLED UNITS.

AEROVOX WIRELESS CORP.489-491-493 Broome Street New York City

PHU 0 UBESShould Be Used in the

TECTRON "B" ELIMINATORfor Quietness in Operation and Maximum

Voltage and Amperage OutputThey were selected by Lewis Winner asthe most suitable for this wonderfulEliminator.

TECTRON RECTIFIER TUBES are built espe-cially for the Eliminator described in this issue.They will deliver the maximum of current andvoltage over a reasonably long period of burninghours.

For real reception,clarity and volumeuse:Tectron 20IA $2.00

Power Tuba 55.00

Price $2.50If your dealer cannot supply you order direct.

Special Prices to Manufacturers

1270 BroadwaySpecial Compact Model Tectron"B" Eliminator, 4x7x7 inches,small enough 35to be placed in the cabinet of a set. Will $ .00deliver up to 150 volts and 60 milliamps. Fully guaranteed.Price, complete, ready to operate

New York

and the District of allumbia. Illinoisleads with 47 applicants. California issecond with 40, and New York is thirdwith 28. A list of states, with the num-ber of applications from each, follows:

Illinois, 47; California, 40; New York,28; Florida, 22 ; Iowa, 18; Massachusetts,18; Pennsylvania, 16; Minnesota, 14;Texas, 13; Nebraska, 13; Maine, 12;Ohio, 12; Indiana, 11; Wisconsin, 11; Ten-nessee, 11; North Carolina, 11; NorthDakota, 9; Missouri, 9; Michigan, 9; Vir-ginia, 8; New Jersey, 7; Oklahoma, 7;Arkansas, 7; Colorado, 6; South Dakota,6; Kansas, 5; Connecticut, 5; Georgia, 5;Alabama, 5; Louisiana, 5; New Hamp-shire, 4; Rhode Island, 4; Vermont, 4;Oregon, 4; Montana, 4; Kentucky, 3;Idaho, 3; West Virginia, 3; Washington,2; Mississippi, 2; Maryland, 1; District ofColumbia, I; Utah, 1; Arizona, 1 ; Wyom-ing, 1, and New Mexico, 1.

Wonder Radio LogThe Weirder Radio Log Co., of Chi-

cago, Ill., is putting out a booklet, com-prising a list of broadcasting stations inthe United States, Alaska, Philippine Is-lands, Canada, Mexico, Cuba and PortoRico, etc., by their call letters, kilocyclesand location. A map and a diary are alsoincluded. The broadcasting stations arestated by call letters. Szace is allowedfor keeping a log of the type of" recep-tion accorded with each station. If anychange occurs in the standing of the pres-ent day stations, there is ample room tomake a note of the change. Alongside ofthe list of the stations by kilocycles, thereare also spaces for placing remarks, asto reception.

TRANSFORMERSCHOKE COILSCONDENSERS

WillEnable You to

Build Your Own

TECTRON"B" BATTERYELIMINATOR

As described byLewis Winner in this issue

Full InstructionsSent on Request

forRAYTHEON

REX, andCHEMICAL

RECTIFIERSPrices on request

SHORE ELECTRIC CO., Inc.64 University place

New York City

All types of specialtransformers builtto specifications


TradiograMs

$650,000,000 YearProphesied For 1926

The output of companies manufacturingradio apparatus has grown from $2,000,000in 1920 to more than $500,000,000 in 1925,says Arthur J. Tryer, Deputy Commis-sioner, Department of Commerce, Bureauof Navigation. He estimated that businessin 1926 would amount to $650,000,000.

Tryer said that development of theradio had been so rapid that the depart-ment found it hard to keep its inspectioninstruments advancing with other appa-ratus.

Freed-Eisemann GetsSix -Story Factory

Freed-Eisemann will occupy a new 6-story and basement building, seven fac-tory floors-at Liberty Avenue and JuniusStreet, in the East New York section,Brooklyn.

FREERADIO

CATALOGWRITE for a copy of

our NEW 100 -PageRadio Catalog-Parts, Ac-cessories - Kits - Sets -Everything for the Fan.

DEPT. R. W.

CHICAGO SALVAGESTOCK STORES511 S. State Street, CHICAGO, U. S. A.

The world's -greatest variable grid leak,distributed by the North American Bret -wood Co., is selling enormously, and isgiving universal satisfaction. Get moreout of your set by using the BretwoodGrid Leak. Mailed for $1.50. Radio Divi-sion, The Columbia Print, 145 W. 45thSt., N. Y. C.

BARBLEY'S FOLDERDealers who are on the lookout for a

new means of stirring up good businesswill receive a beautifully printed folderthat will help them make new radio his-tory, on application to Barbley's RadipService, 135 Liberty St., New York City.The Barbley Brothers are pioneers inradio and are well known for their re-search work. Mention RADIO WORLD.

LOUD SPEAKER RECEPTIONfrom either coast on three tubes

Blueprint and Instructions $1.00Necessary low los, coil 2.50Beautiful finished instrument 35.00

S. A. TWITCHELL CO.1930 Western Avenue Minneapolis, Minn.

WELTY'SDETECTOR

AMPLIFIER UNIT

Can be used In any receiver. ItatremelycoumacL Size 4%09%. All strictlyhigh clam parts. Universal socket.. Distortion -leas transformers. Will handle the volume of any

set. Only 4 connections necessary to hook up toany tuning apparatus. Color scheme binding poets,also switch and Jack. Whenever a detector andtwo stages of sudlo are required you can use thatsplendidly made Welty Unit to decided advantage.It saves time In building. Prins only 318.30.

A NEWSUPERAD1ODINE KIT, $17.50

With Perfectly Matched Transtermer sod Filter

This is a SUPERADIO Product-YourGuarantee of Satisfaction!

The most seleetive, the most Powerful, lengeelranged. finest toned 8 tube super ever designed.Intermediate transformer. matched to Identicalpeaks and filter tuned to same peak. Kit Include.Antenna Coupler. Oscillator Coupler. Medal Va-riable Condenser. Tuned Input Transformer. 3matched intermediate transformers and hardware.Complete with booklet. diagrams and full ailedworking drawings which positively assure perfectsuccess. Onier now. Only $17.50.

Writ, for our free Radio Catalog of parts.

WILLIAM A. WELTY & CO.-36 South State Street, Chicago

Phone: State 5952Radio Dept.

FILL OUT AND MAIL NOWSUBSCRIPTION BLANK

RADIO WORLDRADIO WORLD 145 West 45th Street, New York Cis)

Crust East of Broadway)Please send me RADIO WORLD for months, for which

please find enclosed $SUBSCRIPTION RATES:Single Copy $ .15Three Months 1.50Six Months 1.00One Year, 52 Issues 6.00Add $1.00 a Year for ForeignPostage; 50c for Canadian Poetage.

RADIO BROADCAST Laboratory, wheremany of the Knockout Sets were developed.

Now you can build

ROBERTSRECEIVERS

including the complete series of RadioBroadcast Knockout Receivers. Oneto fit every radio location and pocket-book I

A One -tubeKnockout,the first ofthe series.

A Knockoutemployingtwo tuber --it's aRoberts

Resistancecoupledaudioin KnockoutReceiver

A weltdesignedthree -tubeRoberts

To make it easy to build these efficient setsRadio Broadcast has prepared a book show-ing with cOmplete wiring diagrams and in-structions how to build twelve types oftherm No constructor's data is completewithout this book. These receive, areknown to be good, and the best of It isthat you can test their value for yourselfby means of these clear and interestinginstructions complete and separate for eachreceiver. The cost of this 138 -page book isone -dollar; the technical skiff and experi-mentation behind it are priceless. Send usyour mailing instructions along with onedollar, today. There is only a small edi-tion of these books, printed for the fewwho can appreciate the best.

DOUBLEDAY, PAGE & COMPANY,Garden City, New York

Please find encloeed $1.00 for RADIOBROADCAST'S KNOCKOUTRE-CEIVERS to be sent to

Name

Address


Public Radio MonopolyIs Asked in Britain

LONDON.An official committee has recommended

to Parliament that the control of radio betaken from the British Broadcasting Co.,

Vacuum TubesRebuilt

$1.00 eachPOSITIVELY GUARAN-

TEED equal to new tubes Inevery respect. Money will berefunded If tubes prove un-satisfactory for any reasonother than burn -outs.

Pend us your broken andburned out tubes by payee)pant. (Not necessary to In-sure or guard against break-age.) We make return OOP-ments by parcel post C.G.D.and try to maintain 24 -hourservice

HARVARD RADIOLABORATORIES

200 Old Colony AvenueSouth Boston, Mass.

a private company, and vesting it in apublic corporation.

The constnittee expresses the view thatbroadcasting "will become the handmaidenrather than the usurping rival of literatureand the arts-in fact, we feel justified in

LISTEN TO YOUR LOCAL STATIONSwith

THE TALKING BOOKReg. U. B. Pat. OR.

A complete radio set to the form of a book, houndIn One clath with gold at/diming. Equipped withTowers head phones and antenna.

Guaranteed range fifteen miles.An Ideal ancillary to a tube set. Coats nothing

to operate and lasts forever.Just the set for the children and fine for the

tr...iier MeePRICE FIVE DOLLARS, sent prepaid.Approeed by th Ponular £0510 Laterlot7

Mfg. heLISTEN -IN PUBLISHING CO.

III Main St. Cambridge. Mari.Publiahere of the Litton -in Radio Record.

if you live within ten miles of broartesatimiDutton write for exclusive agency.

Expert "on Location".

THE LOCATION of a loud speakerhas much to do with the quality andvolume of signals, says T. L. Seaman,of the New York office of the Thor-darson Electric Manufacturing Co.Mr. Seaman is shown experimentingwith the location and position of a

cone speaker to get best results.predicting that the long run art willnot he injured by science."

KITS - KITS - KITS AND STILL MORE KITSThe Demand for the 1926 Model, Boxed and Sealed

DIAMOND OF THE AIR KIT...435.00Is Exceeding Our Wildest Expectations. The Country Is Going DIAMOND Crazy!

Recognition Like This Must Be Deserved!No Kit Is Genuine Unless It Bears the Seal and signature of HERMAN BERNARD

"Bruno 99" 3 -circuit tunerwound on quartzite glass andspecified in the Diamond of theAir $5.50

"Bruno 55" matched Radio fre-quency coil for 99 and used inthe Diamond of the Air. .$3.00

"Bruno 77" 3 -circuit tuner wound011 quartzite glass with specialtickler for smooth regenerationcontrol $5.50

"Bruno" short wave coil. Tunesfrom 25-110 meters with .00025condenser. Wound with flatribbon wire $5.50

Here area few of RADIO WORLD'S moat famous kits, which were presented to Its readers In th past few months. The parteIncluded In each are exactly as specified by the authors in the articles. Full Instructions for construction will be Included In eachkit for the convenience of the builders. Our kit department carries nearly every kit ever described, and If not Included in themcolumns, we would be glad to adviee you as to Its price, etc.

rBruno Powsrtone Kit-A 5 -tube single controlreceiver. DescribedAug. 29, Sept. rile)S and Dec. 12.. LG.50

Herbert E. Hayden'sA -A Receiver. An ef-ficient, all-around setDescribed Nov.

22.5014 and 21

1 hordaron Wade Kit-Clarity, Volume and Se-lectivity.Described3, 10, 17 Oct. 41.50

The Bernard DX (-Tube Receiver. Distanceon 1 tube.DescribedOct. 24 7.75

The Pathfinder -A 4 -tube receiver of excep-tional merit.Described Oct7e3i qr31 and Nov. 7 a iI .GJ

IThe 4 -Tube DX Dandy-Herbert E. Hayden'sReceiver.DescribedFeb. 27 15.95

"IMNIMI1==111111M1MMIh.The 3 -Tube, 3 -CircuitReceiver. An efficientDX getter.DescribedOct. 10 18.50

IBernard's Audio Ampli-fier -3 stages of amplifi-cation with volume.DescribedOct. 3 10.50

Bernard's Loudboy -Distance and Volume on1 Tube.DescribedFeb. 21 9.65

ISidney E. Finkeistein'sZ5-110 Meter ShortWave 2 -Tube Set.DescribedSept. 12 12.95

The Famous RX1 Re-ceiver. Described in is-sues of Oct. 1791 cfband 24 A OU

Bruno 3 -Tube DX Set-AU Low Loss PartsUsed for DXand Volume... 18.50

B -C -L RADIO SERVICE C05, 221 FULTON STREET, TELEPHONEGORTLANDT 5020.446


Intimate AdventuresBefore the Microphone(Contmued from Page 19)

realize that his worth was well appreciatedin advance, for an orchestra was beguileointo playing for 25 minutes before his owndramatic entry, to inspirit the audience, if notrecruit them, and for 25 minutes after he hasfinished, so that the thrill of his words wouldstand out in contrast to the commonplacesthat nearly all, America enjoys as jazz

The Other SideYes, the chronological surroundings were

just right! It may never dawn upon himthat an hour's uninterrupted work is tiresomefor an orchestra, so a talker-any kind of atalker, or even a child soprano would do-issandwiched between the halves, merely tostop the gap. While the talker's talk may beeducation-indeed it may even enlightenradioists on the technique of their sets-

We Specialize in Complete KitsThe M. & H. Engineering send., Will Supply Parte

or Complete Sets of Any Hookup

DESCRIBED IN THIS OR ANYOTHER RADIO MAGAZINE

M & H SPORTING GOODS CO.512 Market St. Philadelphia, Pa.

SUPER -HETERODYNESVictoreen-St. James-Remler

Complete parts in stock-WriteWALDEN ELECTRIC CO.

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Please send me FREE, Your NEWRADIO CATALOG

NameAddress

State'FILL OUT AND MAIL

JOHN F. RIDERannounces that his laboratory is now available as aservice institution catering to the radio fan constructorand the broadcast listener.

Also his personal services are available to radio fansas consultant In matters pertaining to radio reC0iVesin all their phases.

Mr. Rider Is the author of the Laboratory ScrapBook appearing each Riturday in the New York SunIshdlo Magazine, Contributing Editor of Radio World,and contributor to, many other leading radio periodicalsin the country.

LABORATORY OF JOHN E. RIDER145 Waft 45th Street New York CityTelephone Bryant 2383

New-DifferentThe Beautiful De /use Radio

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Lime the Broadcasting Stations three convenientways-(11 by Call Letters; (21 by Locations andOwners; (3) by Kilocycles and Meters. Includes24 -page Wonder Radio Diary by months end daysand Wonder Radio Distance Mop. Ample spacefor keeping complete Log and for changes, addi-tions and revision.

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THE WONDER RADIO LOG COMPANY705 So. Dearborn St. Chicago

really he is rated by the whole station, fromthe owner down to the janitor, as merelyhumanitarian, the enjoyers of this social hos-pitality of course being the perspiringmusicians.

It is a fact that perspiration abounds inbroadcasting studios. It is surprising howmuch one can perspire when simply sittingstill. Most broadcasting talkers are seatedduring their period of grief (more like elec

VEBY HIGH -MU TUBESMade esoccIallY for Resistance Coupled Ann/lifters.NOW you can get more volume with greater clarity.A. F. 20 for the 1st and 2nd Stage $3.00A. -F. 6 Power Tube for the 3rd Stage 4.50

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HARD RUBBER PANELSSize. Black

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RIX RADIOSUPPLY HOUSE, Inc.

5505 -4th Ave.Brooklyn, N. Y., U. S. A.

trocution than like hanging), but a stainydampness pervades the chair and sometimesthe carpet. Women talkers have theirtroubles in this direction, too, particularlyunder the arms, even though they articulatewithout a single gesture. Rouge runs fromruby lips and powder is rendered as uselessas a drenched ammunition dump.

Becomes Normal PersonThe day finally dawns when, if the talker

retains sufficient favor at ttfe studio, he be-comes a natural person in all his broadcastingand attendant duties. He speaks and acts

F"PICTURE" DRAWINGSEasily the finest radio prints ever roads

Price, Postpaid-$3.00Build a Laboratory Set with

Fenway Blueprints!LEO FENWAY

29 WEST 64th STREET NEW YORK. N. Y.

ENWAY BLUE PRINTS

221/4 voltrechargeable

"B"StorageBattery

$2.95includeschemical

45 volts. $5.22,:..0 .;10 oo 1114; volts.112.50; 135 volts, $14.73; 15756 volts, $16.80.Truly. the biggest buy today. Easily charged an anycurrent. Including 32 -volt ayateins. special de -term plate voltage had Tested end approved byleading authorities such as Popular Radio Labor-atories. Over 3 years sold on a non -red tape, -30-daytrial offer with complete refund if not thoroughlysatisfied. Further guaranteed 2 years. Knock -downkits at great savings. Complete "Hawley" "B" bat-tery charger. 52.75. Sample cell. 35c. Order direct-send no money-simply Pay the expressman caston delivery. Or write for my free literature, testi-monials and guarantee. Same day shipments. B.Hawley Smith. 316 Washington Ave., Danbury, Conn.

How to BuildTHE FENWA Y

The famous DX set that, by the turn of aswitch, as a 4 -tube tuned RF set, withregeneration, or a 9 -tube Sniper -Hetero-dyne! Remarkably sensitive)Described by Leo Fenway himself in theFebruary 6, 13, 20 and 27 issues, includingtrouble shooting. Send 60c for all four is-sues, or send $6 for year's subscription andget these four copies FREE!RADIO WORLD, 145 W. 45th St., N. Y. C.

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

CONSTRUCTION OF THE 4 -TUBE A -A RE-CEIVER, by Herbert E. Hayden, appeared inRADIO WORLD dated Nov. 21. 15c per copy,or atart your subscripticra with that number.

HERMAN BERNARD, managing editor ofRADIO WORLD. broadcasts every Friday at 7p. m.. from WCBS, Gimbel Bros., N. Y. City.315.6 meters. He discusses "What's Your RadioProblbm?" Listen in I

1626 DIAMOND OF THE AIR BOOKLET withfull inetructione to make the Diamond, with blueprint, 50c. Newsdcalers and radio dealers maget supply from American News Co. and itsbranches. RADIO WORLD. 145 W. 45th St.,N. Y. C.

HEAR JOHN F. RIDER, contributing editor ofRADIO WORLD, broadcast every Thursday at9 Ix m. from WGCP, 252 meters. D. W. May,Inc.. Newark, N. J. Mr. Rider discusses radioProblems.

"ME WANTS MORE DX"-worth framing.This is the front page of RADIO WORLD dated.March 6. If you haven't a copy, get this numberand you will find that this youngster with theearphones is one of the cutest little kids youever saw, except your own, of course. 15c percopy. or start sub. with that number. RADIOWORLD, 145 W. 45th St., N. Y. C.

BULLDOGSBEAUTIFUL REGISTERED BULL PUPS, $15.

Bulldogs, 501 Rockwood, Dallas. Texas.

HELP WANTED MALE-EARN $110 to $250 monthly, expenses paid asRailway Traffic Inspector. We secure position

for you after completion of 3 months' home studycourse or money refunded. Excellent opportuni-ties. Write for Free Booklet, G -16I Stand. Busi-ness Training Inst., Buffalo, N. Y.

'arch 20, 1926 RADIO WORLD 31

freely and easily, with only enough nervous-ness to prevent the fatality of indifference.The supreme moment arrives when themiddle-aged girl who runs the elevator in thestudio building, greets him by name. Thisusually happens just prior to Christmas. If

Eetrifer-11MT4Z.IF YOUR INVENTION Is new and useful It la

patentable. Send me your sketch.Z. H. POLACHEK. 70 Was St.. New Tot

A11.1.11111.Rag. Potent Attorney.Englnee

-Gets Everything

But Noise/Read this convincing letter

from a man who has"listened and marveled":

"Omaha, Nebraska,February 10, 1926.

Kane Antennae Co.,Gentlemen:I received 213D. Aberdeen. Scotland. on a "KaneAntennae," during the recent International Taste.Reception was officially verified by Radio Broad.ceet Mescaline, who conducted the tests. I builtthe Antennae a year ago from one of Your blue

prints. P. has more than met expectations Inthe elimination of outside electrical Interference.

as well as in increased volume and distance.GUY 11. CRAMER."

Improves Reception 60%Entirely eliminates ell power noises such as leaky

tray/Am-mere. generative. motor hunts. Delco

Plants. etc. Cuts static and regeneration howls

and suueels In two. Dr. Gehrig of Oakland. Cel.,wys it improves his reception fully 60 per cent.Do away forever With disagreeable noises.

-erimngp.eSteL UlitrPkRinigNTDrawing$1.00 Brings

and full instructions for erectingOhl. wonderful

Antennae. Just send $1.00 (a check will do.Stamps not accepted). A ilemeed number

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Dept.1330.C. 3034 W. Van Buren it., Chicatio.111.Dealers-Send al Once for Attractive Proposition.

KANE ANTENNAE

RADIO AGEThe Magazine with

BLUEPRINTS

by coincidence one starts his broadcastingcareer at that time, the incident of the ele-vator girl surely will turn any man's head)For at the beginning he is expecting much,while later on he expects nothing in particu-lar and receives all of that and less.

Finally, after several months of steadyappearance, the artist begins to feel like aman on parole, reporting to headquarterseach week lest he be "sent back" for viola-tion. It becomes part of the steady grindthat helps make this life bearable and todistinguish it from the next.

9 Heard You"He has ceased to inquire of all who honor

him with their presence whether they listenedin the other night when he was on.

He seldom mentions his broadcasting butis glad when some one voluntarily tells him

Locate at

RADIO CENTERBush Building

130 West 42nd St. New York City

Mailing ListsWill help you increase sales

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PRICE OF COMPLETE SET OFBLUERINTS-$3.00 Postpaid

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Clockwise 0-200 (360°) 2.50 3.00

Send for Bulletin 109 RWNATIONAL CO., INC., 110 Brookline Street, Cambridge, Mass.

W. A. READY, President

lie listened night before last. There is littlehe can say in fair return. It is absurd to ask,"How did you like it?" It invites disaster ordiplomacy, and both are bad, world historyof twelve years ago having proven diplomacythe worse. No plea for utter frankness isgenuine, for no broadcaster, not even a meretalker, and certainly not a singer or instru-mentalist, wants to hear adverse criticism.He may say that he welcomes it, but, if hehas any brains, he is conscious of his ownshortcomings, and if he hasn't any shortcom-ings he hasn't any brains.

OLD TIME RECEIVER PRAISEDRESULTS EDITOR:

I have been a regular reader of yourmagazine ever since it first came on themarket. I have made several of the setsthe many contributors have given. Imade a set described by Herman Bernardtwo years ago and have heard the follow-ing cities: Cleveland, Schnectady, Pitts-burgh, Philadelphia, Chicago, Cincinnatiand Davenport. In all the sets that Imade from the drawitigs in RADIO WORLD,

every one has worked successfully. Thisis more than 1. can say about othermagazines.

JOS. P. LEWIS,3826 Dennison Place, N. W.,

Washington, D. C.

It's Easyto Build. aPowerful SetUsing the New andImproved FRESHMAN"TRF" Low Loss Kit

GkEATEST -RADIOREC

MitAti-Em"R;TE'Ci

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Straight Line Wave LengthCondensers With Low LossSelf Balanced CoilsThese are the iden-tical units whichhave made theFRESHMANMASTERPIECEfactory built Receivers the World'sGreatest Radio Sets,Complete instructions for buildingthis powerful five tube receiver,written in plain everyday English,together with actual size schematicwiring diagram, are furnished withevery FRESHMAN "TRF" Kit.

Sold by AuthorizedFreshman Dealers Only!

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2626 W. Washington Blvd., Chicago437InglIn

50

RADIO WORLD March 20, 1926

CHAS. W. DOWNIS THE

FENWAYSPECIALIST

"Look UpDown

He Has All theParts RequiredAs Well As In-formation Pre-taining to the

THE NEW MODIFIED

"UNIVERSAL"THE IDEAL RECEIVER OF

THE DAYPARTS REQUIRED

2 General Radio Type 277D Coils. or I GeneralRadio Typo 277.D Coll and I General RadioType 277.6 Coll.

4 General Radio Type 349 SaoketsI General Radio Tyne 968 1,1Iero Condenser2 General Radio Type 274H Condensers

While the cells are such that the best rangewill be obtained with the Type 274-H Condensers. the Type 334-H Condenser, may besubstttuted when so desired.

I General Radio Type 901-10 ohm RheostatI General Radio Type 301-30 ohm Rheostat2 General Radio Type 285-L Audio Transformers,

or I General Radio Type 285 Audio Trans.former and 1 General Radio Type 285.6. AudioTransformer

I General Radio Type 274 Telephone Plug andJack

Send for Free Booklet ContainingIt's

I General Radio Type 230 0.5 MF. Fixed Con.denser

I General Radio Type 138.2 Binding Posts2 Gneral Radio Type 310 Diets

I .0001 MF. Fixed Condenser1 .00025 MF. Flood CondenserI Durham Grid Leak 2 Meg.I Durham Grld Leak Mounting2 Radian Co. "Amperites" with Mountings (tor.

reef type for taken used)I Eleetrad Royalty Resistance Type C (500 to50.000 ohms)I Panel 7"e18"e3/16"I Baseboard 7"a 17"x Vs"1 Terminal Strip 9 3/4"ic 1 Ve "03/16"

I Ynaley Filament Switch2 Brackets 11/2"s1 Vs"aVa" (may be obtained at

any hardware store)I Special Bracket, as shown In Fit. 5h

Full Details, Hookups, Photos, etc.Free.

FENWAYLIST OF PARTS FOR THE FENWAY"

1 Special Drilled and Engraved Panel as specified$10.001 Special Hardwood Baseboard

1.001 Set of Four Special Copper Cans, Black Satin Finish, per set 11.001 Sub Panel, Drilled and Engraved1.253 General Radio Variable Condensers, .00035, each 53.75 11.251 General Radio Medium Frequency Input Transformer No. 331 5.003 General Radio Medium Frequency Input Transformers,

each $5.00 15.002 General Radio 6 -ohm Rheostats, No. 301, each $L25 2.501 General Radio 400 -ohm Potentiometer, No. 214 3.002 General Radio Audio Transformers I. No. 285 and 1 No. 285-1-,each 56.00 12.002 Silver -Marshall Changeable Coils, No. 110-A and 1 No. 111-A, each

$2.50 5.002 Silver -Marshall Coil Sockets for No. 110-A and No. 111-A, each $1.00 2.001 Special R. F. Variable Coupler mounted on sub panel with switch

and taps, all wound ready for use 6.003 Gem Fuses and Base 1.001 Royalty Type B Resistance 1.501 Yaxley Filament Switch -501 Yaxley Filament Control Jack .701 Yaxley 2 Circuit Jack .80

Yaxley D. P. D. T. Switch, No. 60$1.25Air -Gap Sockets, each 75c6.75National Vernier Dials (new type), each $2.507.50Eby Binding Posts, each 15c1.200 -Foot Celataite Wire, per foot, 4c 2.00Jewell Combination Volt Meter 0 to 8-80-160 12.50Jewell Meter 0 to 50 Milli -Amps 7.50Micamold Condenses. Grid .000n .35

Micamold Condenser Grid .0005 .45Micamold Condenser By -Pass .001 .40Micamold Condenser By -Pass .01Micamold Condenser By -Pass .5, each 90c 2.70Micamold Grid Leak 2 Megs. .30Micamold Grid Leak S Megs. .30Micamold Grid Leak Mount .30

.90

Total $133.00

NOTE -Silver -Marshall Transformers can be supplied at an additionalcost of $4.00 per set.

NOTE -For those desiring to wind their own coils, coupler and otherspecial parts, the proper parts may be had on receipt of order for (AMA.

SILVEROCKAMY.

Ihgkconlithilltea& recariat

COVERS BANDSOF

50 To 1800 MetersComplete Parts in Stock With Full Instructions for

Building and Operating. Special S -C Booklet, Contain-ing Full Details, Hookup, Photos, etc.

SENT ON RECEIPT OF PRICE, 25 CENTS

"Look UpDown"

Complete Radio TestingLaboratory for the Cor-rection of Radio Troubles.

CHARLES W. DOWN711 Eighth Avenue New York CityBet. 45th & 48th Sts.) Phones Peon. 7779'

Special Mail Order Dept.All Orders Shipped Same

Day Received.Wholesale Prices Quoted to

Bonafide Dealers Only!YOUR MONEY REFUNDED IF

NOT SATISFIED!

march 20 15 cents rac i 0 a 2 -tube speaker set le reg. u ...€¦ · guaranteed precision range...

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