MARCH 6 15 CENTS

Vol. 8 No. 24 ILLUSTRATED Every Week

RADIOA 1 - TUBE, 1 - DIAL RECEIVER

COILS FOR SLF CONDENSERS

W O R L D AN ASTATIC CRYSTAL ET

DIAMOND EFFICIENCY DATA

"ME WANTS MORE DX!" From a pastel by G. J KIia

1

1

1

31

3

21

2

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List of Parts for the "Fenway"Special Drilled and Engraved Panel as specified passSpecial Hardwood Baseboard 1.00Set of Four Special Copper Cans, Black Satin Finish,

per set 11.00Sub Panel, Drilled and Engraved 1.25General Radio Variable Condensers, 00035, each $3.75 11.25General Radio Medium Frequency Input Transformer

No. 331 5.00General Radio Medium Frequency Input Trans-

formers, No. 271, each $5.00 15.00General Radio 6 -ohm Rheostats, No. 301, each $1.25 2.50General Radio 403 -ohm Potentiometer, No. 214 3.00General Radio Audio Transformers I, No. 285 and 1

No. 285-L, each $6.00 12.00Silver -Marshall Changeable Coils, No. 110-A and 1

No. 111-A, each $2.50S.00Silver-Marshall

Coil Sockets for No. 110-A and No111-A, each $1.00 2.00

Special R. F. Variable Coupler mounted on sub panelwith switch and taps, all wound ready for use GM

C,em Futses and Base 1.00Royalty Type B Resistance 1.50Yaxley Filament Switch .50Yaxley Filament Control Jack .70Yaxley 2 Orcuit jack .80

Chas. W. Downis the

FENWAySPECIALIST

LOOK UP DOWNSUPER -HETERODYNE

SPECIALIST

A Complete Radio Testing and ResearchLaboratory for the Correction of RadioTroubles.

WIRING AND REPAIRS WITH RESULTSGUARANTEED

CHAS. W. DOWN,711 Eighth Avenue New York, N. Y.Bet. 446 and 45th Sta. Penn. 7779

1 Yaxley D. P. D. T. Switch No. 60 $1.259 Air -Gap Sockets, each 75c 6.753 National Vernier Dials (new type. each $2.50 7.50

Eby Binding Posts, each 15c 1.2050 -Foot Celatsiee nitro, per foot, 4c 2.0*1 Jewell Combination Volt Meter II to 840-100 12.5e1 Jewell Meter 0 to 50 MillisAmps 7.501 Micamold Condenser Grid .00025 .351 Micamold Condenser Grid .0005 .451 Micamold Condenser ByPaas .001 .40

1 Micamold Condenser By -Pass .01 .903 Micamold Condenser By -Pass .5, each 90c 2.701 Micamold Grid Leak 2 Mega. .301 Micamold Grid Leak 5 Mega. .301 Micamold Grid Leak Mount .30

Total $133.90NOTE -Silver -Marshall Transformers can be supplied at an addi-

tional cost of 24.00 per set.NOTE -For those desiring to wind their own coils, coupler and

other special parts, the proper parts may be had on receipt of orderfor same. A Micamold .04 fixed condenser will make any conespeaker work better. Try one. Fenway recommends a cone speakerfor the Fenway.Cabinets for the Fenway now in stock....$2230New type National dials now in stock. All types of meter. andspecial parts. A hill stock of nickel, wood and machine screws..04 Micamold condensers in stock. A special mail order departmentfor prompt service. All orders shipped same day received.

(Wholesale Prices Quoted to Bonafide Dealers Only)

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resenting on the shaft of toy standard type of Tenable condenser. without the us of tools other than Ogren driver. It will replace plain dish on any nearer when sharper tuning Is delayed.

Of menet impora is new sad novel dodos which enables the user to adjust at ortll the rodustleato ear rates fns 8-1

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RADIO DEVELOPMENTSRADIO WORLD

16 WEST 45th ST. NEW YORK CITY

RADIO WORLDf Entered es second-class matter, March, 1922, at the post o Site at New York, N. Y.. under Act of March 3. 13791

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

Vol. VIII. No. 24. Whole No. 206 March 6, 1926 15c per copy, $6.00 a year

The Old Salt

'N.-0 +A -B

A

CIRCUIT diagram of the 1 -controlset.

By Capt. P. V. O'RourkeSEEING an old salt box lying around

the house, which had been discardedby friend wife, gave me the idea for con-structing the unique receiver shown in thephotos and in the circuit diagram.

The salt box is used as a cabinet. Onlyone dial is employed. There is not evena rheostat to turn. Therefore simplicityin tuning is certainly assured.

Appraisal of SetThe receiver is, of course, not the most

selective or the most voluminous everdesigned, but it is one of the simplest aswell as amply efficient for the parts andspace employed. Another interestingfactor is that a dry cell tube is used. Thehookup used is of the single circuit re-generative type, with the grid and platecapacitively coupled to the antenna andground systems. The complete receivertakes up no more than a 5" space. Onlythe variable, and fixed condensers andthe coil are in the cabinet. The socketfor the tube, grid leak and the ballast re-sistor as well as the dial are on the out-side of the cabinet. A switch may be putat the rear. The A and B batteries takeup more space than the receiver itself.

Fig. 1 shows the type of salt box thatwas employed to make the cabinet. Evenif you haven't this in the house, it can bebought at a hardware or chain store fora few cents. The incline where the lidis, rises usually 8 or 9". It is a goodidea first to scratch the words Salt fromthe cabinet with a penknife or sandpaperthem off with some emery paper. Nowlook at Fig. 1 and note the little hole atthe top of the box. You will also notethat the portion surrounding this holestands alone and can easily be sawed off.This we see being done in Fig. 3.

The Sawing ProcessHowever if you just saw this piece off

and try to push the lid, so that it acts thepanel, there is large space above the lid.Therefore you will have to saw this pieceoff also. This is being done in Fig. 3.The best way to do this, is to draw aline parallel to each inclining line on eachside of the box. Then when you saw thetop and the sides off, you will have anearly perfect square box, with just asmall slanting place for the placing of thepanel. The lid is used as the panel

FIG. I, showing the plain salt box.Fig. 4 gives a clear idea of how the cutportions appear.

Now sandpaper the complete cabinetwith emery paper. Wipe the dust off andgive the box a coat of shellac. Let itdry. Then obtain some stain, the colorof which may be best determined by thebuilder. Black pitch is the color I pickedand it certainly makes a clean lookingjob. Mahogany stain is very difficult toplace on the wood. Most of these boxesare made of soft wood. Therefore theabsorbing nature of the wood is too pro-nounced. The mahogany stain thereforewill not apply smoothly over the wood.The black spreads more readily. Let thebox stand for a couple of hours until thestain has soaked into the wood. A coatof shellac may be placed over the coatof stain if desired. This gives the boxa glossy coating. Of course before add-ing each coat of paint or shellac, thewood has to be absolutely dry.

Now take the lid out of the box. Drill

LIST OF PARTSOne antenna coil, L.One .0005 mfd. variable condenser, Cl.Two .00025 mfd. fixed condensers, C4

and C2.One .0005 mfd. fixed condenser, C3.One .001 mfd. fixed condenser, CS.One 2 megohm grid leak, R2.One 1/4 ampere ballast resistor, RI,

(Amperite, No. D-11).One salt box.One Bruno Magic dial.One switch.One socket.Accessories: One dry cell tube (WX12),

one pair of phones, five binding posts,connecting wire, 2" square piece of tin-foil, screws, A and B batteries, etc.

One TubeOne Dial

FIG. 2 (top), scraping the word"salt" off the wood. Fig. 3, (bottom),

sawing the boz.

a hole exactly in the center. This lid isapproximately 4%" square. ThereforeDA" from the top and the bottom as wellas the sides, drill a hole for the shaft ofthe variable condenser. Now on the sideopposite to that where the dial will ap-pear, on the panel proper, place a pieceof tin foil, which should be about 2'square. This tin foil should be glued tothe panel, but placed in such a mannerthat it does not touch the condenserproper.

Mounting AdviceNow mount the condenser. If you use

the same type of dial as in the photo-graph, (Bruno Magic Dial), you willsimply drill a hole for the holding ofthe dial in place. The dial requires noscrews or bolts for mounting. The con-denser used in the receiver pictured isone that requires only a single hole formounting, therefore, it is necessary onlyto drill these two holes. To hold the panelin place, holes in the side of thebox have to be drilled. There should betwo on each side. The exaot position ofthese holes depends upon the thicknessof the wood in the box.

The socket and the resistances are tobe mounted now. The socket, which isof the standard type, is placed in thecenter of the top as per Fig. 8. Thefilament posts should face the left-handside while the plate and the grid postsshould face the right-hand side. Thismeans that the posts will be on the op-posite sides, with no posts in the frontor back. The ballast resistor is mountedopposite the filament posts of the socket.The grid resistor (leak) is placed oppositethe G post on the socket.

Drill four holes opposite each post of

lk rt 1J 1 VV kJ 1/ Inarell 0, 1YLO

Assembly of the 1 -Tube Set

FIG. 4, (top), showing the sawed offportions, with the stained box. Fig.5, (bottom), pencil pointing to thecenter hole for the variable condenser.Note the hole on the top, drilled forthe purpose of holding the dial in

position.

the socket, so that the connections fromthe coil can be brought through the wood.The coil, which will be described shortly,is mounted in the back of the cabinetproper and not on the variable condenser.The binding posts for the Ant., etc., areplaced on the back of the cabinet. Thiswill be the portion of wood opposite tothe portion holding the dial and variablecondenser.

Coil DataWe now turn our attention to the con-

struction of the coil, which is of thespider weave continuous winding type.This coil consists of 70 turns of No. 24single silk covered wire. A regulationspider weave form about 5%" outsidediameter, with a center hub of 1/2", isused. In Fig. 9, the spokes, of whichthere are nine, are shown being takenout. In order to make the windings hold,cotton is placed in through the turns(where the wire passes under and overthe spokes). The under two and the overtwo method is used in winding the coil.

Now in order to mount the coil, getsome strips of hard rubber, 7" in lengthand /8" in width. Run this through thelarge spaces of the coil. Get four angleirons. Mount one on each side of thestrip in the inverted L shape. Nowmount the other two angles, one on eachside in the regular L form. This meansthat you will have a square form whichhas one side knocked out, on each sideof the coil. Where the screw joins thetwo angle irons, place regular posts andbring the leads from the coil. The coilnow mounted will have its surface 1"above the surface of the base. The coil,instead, may simply be mounted on adowel driven into the wood, or, rather(rally, on a matchstick.

Now that all the parts are placed, thewiring of the receiver shall be attendedto.

Wiring DirectionsThe beginning of the coil goes to the

antenna binding post. It also goes toone terminal of C3 and to one terminalof C2. The other terminal of C3 goes to

FIG. 6 (top), showing the tin foilplaced on the back of the lid or panel.Fig. 7 (bottom), showing the spacingbetween the plates of the condenser.

FIG. 8, thec o m pletedr eceivershowing thedry celltube a n dBrunoMagic dial,as well asthe socket,A mperiteand grid

leak.

the P post on the socket. This connec-tion will have to go through the top ofthe board. These small fixed condensersare held in place by the connections. Awire from the P post goes to one phonepost and to one terminal of C5. Theother terminal of C2, one terminal whichwas connected to the antenna bindingpost, goes to the rotary plates of thevariable condenser, Cl, and to the groundpost. The stationary plates of this vari-able condenser, goes to the ending of thecoil and to one terminal of C4. The otherterminal of C4 goes to one terminal ofthe grid resistance, R2, and to the G poston the socket. The other terminal ofthe grid resistance goes to one terminalof a filament switch. The other terminalof the filament switch goes to the A plus,B minus posts. This means that thistube has a positive grid return. A %ballast resistor, RI, is placed in serieswith the minus side of the filament. Theother terminal of the fixed condenser, CS,goes to the other phone post and to theB plus post. The tin foil is grounded.

When wiring this receiver, either flex-ible or regulation bus wire should beused. The bus wire serves as a betterholder of the fixed condensers, but thedifference between the conductivity of thetwo is nil.

Hints on Successful OperationA 1/, volt battery is used to supply the

FIG. 9, placing the cotton in betweenthe turn.. Note the pegs of the form.

FIG. 10, showing how to mount thecoil on a matchstick, instead of themore complicated affair, explained inthe text, and how to construct and

bind coil.

filament voltage. Do not use a singleunit, but place two or three batteries ofthe same voltage in parallel. The plateof the tube should receive about 45 volts.However, if you find that the tube doesnot oscillate freely enough, then increasethe voltage to about 67%. The properplate voltage is a very important factorin determining the oscillatory action ofthe tube. The variable condenser is usedto tune in stations. If you find that theset oscillates too much, decrease platevoltage. The taking out of the fixedcondenser, CS, may also increase thevolume of the signals to a certain extent.

The Dial

A word about the dial. Used with astraightline capacity condenser-the semi-circular plate type-it converts the tuning

to a straight-line frequency basis.

March 6, 1926 RADIO WORLD

Coils for SLF CondensersMemory Data Given for

the Most Popular Ca-pacities.

HLREWITH are given data on wind-ing radio -frequency transformers

and 3 -circuit tuners, whereby secondariesof both the RFT and the tuner may beshunted by the three popular model vari-able condensers, .00025 mfd., .00035 or.000375 mfd., and the .0005 mfd. SLFtypes. Solenoid type forms are used.These include loose basket weave, airand solid forms. In the loose basketweave form, the spokes are W in di-ameter.

The tickler in each case is wound withNo. 26 single silk covered wire. Theprimary in each case consist of 10 turnsof the same kind of wire used on thesecondary spaced %" from secondary.

Coil DataNo. 20 DCC wire:-.00025 mfd. SLF

variable condenser.Secondary -44" diameter, -128 turns.

Tickler -15e diameter, 40 turns.Secondary -3"-80 turns. Tickler -2'

-35 turns.Secondary -33C-70 turns. Tickler -

2445 -30 turns.No. 20 DCC wire:-.000375 or .00035

mfd. SLF variable condenser.Secondary -2W-93 turns. Tickler-

IX550 turns.Secondary -3"-70 turns. Tickler -2"

-45 turns.Secondary34e-53 turns. Tickler -

23,4° -30 turns.The tickler windings are of the same

in the following instances as for previous-ly cited equal diameters.

No. 20 DCC wire:-.0005 mfd. SLFvariable condenser.

Secondary -2W'-70 turns.Secondary -3"--46 turns.Secondary -4.4"-38 turns.No. 22 DCC wire:-.00025 mfd. SLF

variable condenser.Secondary -2t/,"-110 turns.Secondary -3"-70 turns.Secondary -344"--66 turns.No. 22 DCC wire:-.000375 mfd. SLF

variable condenser.Secondary -2W-88 turns.Secondary -3"-60 turns.Secondary -334e-46 turns.No. 22 DCC wire:-.0005 mfd. SLF

variable condenser.Secondary -2W-66 turns.Secondary -3"--45 turns.Secondary -3w-35 turns.No. 24 DCC wire:-.00025 mfd. SLF

variable condenser.Secondary -2W-102 turns.Secondary -3"-65 turns.Secondary -3W-55 turns.No. 24 DCC wire:-.000375 mfd. SLF

variable condenser.Secondary -2W-78 turns.Secondary -3"-56 turns.Seeondary-W-42 turns.No. 24 DCC wire:-.0005 mid. SI.F

variable condenser.Secondary -2345-62 turns.Secondary -35-44 turns.Secondary -3w-32 turns.When winding the tickler coil, where

the number of turns is so great, thata single layer cannot be made, the hap -bastard manner should be employed.

For winding basket weave coils thesame number of turns may be used, withthe same wind of wire.

PART 1 OF RADIO WORLD'S B BATTERYRUMINATORS appeared In RADIO WORIMdated Ike. IS. Other peat rtieles hi that issue.lie per caw ory start your sub. with that number.RADIO WORLD, 11! W. 17th St.. N. Y. C.

ONE method of winding a coil on a solid solenoid form with the primary, LI,alongside of the secondary, L2, is shown above.

Forecasts of ReceptionConditions Are Planned

By Thomas StevensonWashington. ---Forecasts of radio re-ception by the Government, somewhat

along the lines of daily weather reports,are awaited with interest. Such a dailyservice to the millions of radio fans hasbeen considered by several Governmentagencies at Washington. Experimentalwork has been done by the Bureau ofStandards to establish the connection be-tween the weather and radio reception.Officials of the Bureau of Standards arenone too well pleased with the progressof these experiments, but they are con-fident the time will come when they willknow more about it.

Weather Bureau experts do not believethe experimental work has yet progressedto a point where it would be safe in thenear future to prepare daily radio recep-tion forecasts.

Washington officials have been watch-ing with particular interest the experi-ment of the Nebraska Wesleyan Uni-versity in preparing daily radio forecasts.

For the past several months, J. C. Jen-sen, of the Department of Physics of theNebraska University, has prepared adaily radio reception forecast which isbroadcast through Station WCAJ at 4:30.

"As a result of years of study and in-vestigation," says Mr. Jensen, "the UnitedStates has come tb be depended upon asa reliable source of information concern-ing weather conditions. Farmers cuttheir hay when fair weather is predictedand city folk delay their automobile pic-nics over unpaved roads when the fore-caster says 'Thunder storms probable.'

"With so many people now dependinglargely on radio for their entertainment,and with the quality of that entertainmentvarying so much from night to night,any plan by which receiving conditionsmay be predicted with reasonable ac-curacy should be of general interest. Ifthe radio fan can be forewarned thatstatic will be unusually bad, he can changehis plan for a radio party, and go to themovies.

"If he knows beforehand that signalswill he weak from the southeast but

good to the north and west, he can savetime by tuning directly for Los Angeles,or Denver, or Minneapolis, instead ofsaying 'Why can't I get Havana to-night?' after a prolonged effort. Thatthis very thing may soon come about asa regular feature of weather forecastingis not at all improbable.

"Many studies have already been madein this field. Among them may be men-tioned the researches of Dr. L. W. Austinof the U. S. Naval Laboratory at Wash-ington, Dr. G. W. Pickard of Boston,Professor Van Cleef of Ohio State Uni-versity, the American Radio RelayLeague, and the U. S. Bureau of Stan-dards.

"It is well known that heavy static isworst in the southeast quadrant of a lowbarometer area, and that the cloudy toclear days following the passage of astorm are favorable for radio work. Itis also known that signals are strongerat night than in the daytime, and thatfading is much less troublesome in day-light.

"In the radio laboratory at NebraskaWesleyan University the measurement ofsignal audibilities and the recording offading curves has received considerableattention. A paper on the relation ofradio audibilities to weather conditions,by M. P. Brunig, was published threeyears ago in the Monthly Weather Re-view. Being located in the center of theUnited States with broadcasting stationsin every direction, this laboratory hasunusual opportunities for plotting fadingcurves from the four points of the com-pass, and hence from regions of differentbarometric conditions, in the same even-ing.

"On the basis of these studies, a dailyradio forecast is prepared by myself andbroadcast from WCAJ at 4:30 P. M. Thefollowing forecast for December 15, 1925is typical:

"'For eastern Nebraska: A good radionight; free from static. The best rangesmay be expected from the east, northeast,and northwest. Considerable fading isprobable from the south.'(Copyright 1926 by Stevenson Radio Syndicatu)

The Chemistry of BatteriesThe Importance of Chemi-

cal and Physical Controlof Materials EnteringInto Storage Batteries isDiscussed by an Expert.

By A. R. ReidChief Chemist, U. S. Light & Heat Corp.'-u HE service received from any storage1 battery is dependent entirely upon

the material which enters that batteryand, as with anything else, it will breakdown at its weakest point. No matterhow strong or of how high quality therest of the battery may be it will lastno longer than if all its other parts werebut as strong as its weakest point.

The only guides to strength and qualityof materials are in the analyzing andtesting of such materials. This is a farmore complicated task than the averageperson, or even the average battery serv-ice station man, realizes and requires notonly extensive equipment but also theutmost skill.

Effect on Life and PerformanceTo make clear the importance of such

accurate control it is best to considerwhat effect defective materials will haveon the performance and life of a battery.In taking this point of view let us firstconsider the lead antimony alloy thatgoes to make up the grids. As a batterycontinues in service the grids become cor-roded deeper and deeper, allowing anyimpurities in the metal to be dissolved bythe electrolyte and so become active with-in the cell. The more common impuritiesin the grid metal are arsenic, tin, copperand iron. The effects of arsenic and tinare not very pronounced, though theytend to cause internal discharge of thenegative plate when the cells are idle.

Copper brings about the same result,but its action is much more pronounced,consequently it must be more carefullyguarded against and much smaller quan-tities permitted in the metal. These met-als act by depositing on the active mate-rial of the negative plate and there set-ting up minute voltaic cells which act todischarge the plate. A very peculiar yetvery harmful effect is the result of twoor more impurities acting in this way, inthat their discharge of the negative isfar more pronounced than would be thecase if both were free to act alone. Thiscondition adds considerably to the hazardof metallic impurities.

Iron Most InjuriousIron, whose behavior is somewhat dif-

ferent from the aforementioned metallicimpurities, is probably the most injuriousof all those commonly met in storagebattery materials, for its action is to rapid-ly discharge both the positive and negativeplates on open circuit. Because prac-tically all the equipment used in makingup the lead alloy and the battery oxidesis of iron the resulting materials areinvariably contaminated to some extentwith this very undesirable impurity. Ironexists in two forms, the ferrous or vivalentand ferric or trivalent. Under proper in-fluences it readily changes from one tothe other and it is this property whichrenders it so troublesome in the cells ofa storage battery.

The ferric iron migrates to the negativeplate, where it changes to the ferrous byloosing one of its charges to the plate.As this charge is positive it tends to dis-charge the negative plate. The ferrous

iron then migrates again to the positiveplate, where it is again oxidized to theferric condition, taking a charge fromthe positive plate and thereby tending todischarge it. This action goes on con-stantly and discharge is proportional tothe quantity of iron present. Realizationof the extent of the harmful influence ofiron can only be effected when it isknown that at normal temperature ittakes but .5 of one per cent of iron inthe electrolyte to completely dischargea battery on open circuit in 20 days.

Lead Oxide EffectsTo go to the next and most important

material entering into a battery we mustconsider the lead oxides of which theactive materials are formed. Unlike thegrid metal all impurities contained in thelead oxides are introduced 100% into theelectrolyte, where their detrimental effectstake place as soon as the battery is built.It is for this reason that the most rigidspecifications are given to cover theoxides and unless these are strictly ad-hered to trouble is bound to result. Inthe oxides iron is the most common im-purity found and unless the manufacturerexercises the utmost care it will enter thematerial in excessive quantities and oncethere it cannot be removed.

Copper is also found to some extent butthis can be kept at a minimum by select-ing only low copper lead for oxide manu-facture, whereas iron is accumulatedduring the process of manufacture. Be-cause of better control in the productionof pure lead for subsequent oxidation thanis possible with' the grid alloy the othermetallic impurities are in almost negligiblequantities, yet a broad analytical controlis necessary to avoid their occurrencethrough variations in the lead ores orthrough some failure in the refining pro-cesses.

As the performance of a battery de-pends upon the physical characteristicsof the oxides it is necessary to exercisephysical control over these materialsalong with chemical search for impurities.The apparent density and the texture ofthe oxides are very important and mustbe uniformly maintained. Chemical teststo determine the activity of the oxidesare also necessary. This physical andchemical control of the oxides is of theutmost importance in maintaining qualityand uniformity of the product and inter-pretation of the results of the tests re-quires the greatest analytical and engin-eering ability.

While different characteristics are de-manded by different services or by thevarious manufacturers it is absolutelynecessary that the material be held uni-form or wide variations in the perform-ances and lives of the resulting batterieswill follow.

As the processes of manufacture have agreat bearing on the resulting oxides, andin a number of cases the manufacturerseven vary their processes at will accord-ing to conditions or demands, the numberof different grades of oxides on themarket is very great. While most arecrystalline in structure the variationscome through the texture of thesecrystals, a source of variations which isunlimited. While the crystals throughtheir texture play a very important partin the subsequent active material, yet aconsideration of them alone will lead tonaught unless their behavior to othertests is also taken into consideration.

Effect on DensityDifferent crystal combinations have a

great bearing upon the apparent density

and activity of the oxides, yet these twoproperties may not run proportionately.Densities, however, have a very greatbearing on costs as it is this factor whichmakes plates light or heavy.

Capacities, especially at high rates,show a tendency to follow activity of theoxides but treatment in processes maycompletely alter this; therefore, withoutknowing the effect of a particular pro-cess on an oxide it is impossible to statewhat the battery performances will befrom a study of the characteristics of theoxides. On the other hand, a batterymanufacturer may have a certain processthrough which but one oxide or combina-tion will work successfully. Should heuse any other grade of material he maysuffer an appreciable loss of service fromhis product or an increase in cost or both.

Having considered the metal and oxidesentering into a battery we can now turnto the third material which plays an im-portant part in every battery, a partwhich is entirely chemical in nature andin which all impurities are in their activestates. This material is the electrolyte,dilute sulfuric acid. It is into the elec-trolyte that the impurities in the oxidesand grid metal find their way in the formof soluble sulfates and in which formthey are harmfully active in that theycause internal discharge.

Iron in the AcidThe chief impurity found in battery

acid is iron again. However, it is not asapt to occur in as great percentages asit does in the oxides, yet unless extremecare is exercised in the manufacture ofthe acid it will occur in large quantities.While the manufacturers use every carepossible to keep it at a minimum yet itis always present to some extent andtherefore requires consideration lest itspercentage run above the allowable limit.

Another class of impurities met in theelectrolyte but not in the metal or oxidesis foreign acids. Unlike the metallic im-purities the foreign acids have a tendencyto increase the capacity of a battery butonly at the expense of its life. Their ac-tion is that of a corroding agent, attack-ing the active materials and the grids,making them more porous or spongy andcausing a washing away of the verymaterials themselves. Because of theiralmost unbelievable corroding power theyare sought out in the electroylte by themost sensitive chemical analyses possible.To illustrate how important it is that theybe absent and how powerful their cor-rosive action it is only necessary to stopto consider that the limit of nitric acidpresent in battery electrolyte as specifiedby the U. S. Government, is four one -thousandths of one percent. Other foreignacids are also limited to about the samequantity and if present in excess showcorrosion of the active materials and gridswith appreciable shortening of life. Am-monia and organic matter sometimes findtheir way into battery electrolyte. Insmall quantities of less than .005%, theyare not considered dangerous, but shouldthey occur in large quantities they cer-tainly are injurious. Ammonia tends to de-crease the capacity of the cell whileorganic matter retards charging of thepositive plates. Ammonia is permanentin a cell while on the other hand organicmatter is gradually destroyed.

Needs SupervisionWhile the occurrence of each or both

of these impurities in excessive quantitiesis not very common, yet it must beguarded against or very serious resultsmay be encountered.

March 6, 1926 RA I) I t) (IN I I) 7

An Astatic Crystal Set

THE WIRING DIAGRAM of Freer'sAstatic Crystal Receiver, which he says

cuts out powerful Locals. (Fig. 1).

d"

A -

THE DETAIL of the fixed coil. (Fig. 2).A variocoupler may be used instead, theprimary being variable, but the gain is

slight, Mr. Freer reports.

By Frank FreerTHIS hookup of an astatic coil crystal

set has been used by me about fouryears. Located in Newark, N. J., aboutthree miles from station WOR and twoand a half miles from stations WBPIand WGCP, the set separates these sta-tions and tunes in and out stationsWRAF and WJZ. This set was tested inMaryland, about 20 miles from Wash-ington, and the Washington stations wereas loud as on a good 1 -tube set. Recep-tion of radio signals in Washington ismuch better than what we enjoy in thevicinity of New York.

A medium-sized antenna will run thisset. My antenna is a flat -top V -type,which is led in and connected to adouble -pole, double throw switch. Theantenna, with lead-in, is about 100 feetlong. The advantage gained by erectingthis type of antenna is, you canoften overcome considerable local inter-ference and can cut the length of yourantenna in half when using a regenerativetube set.

The inductance in this set is astatic, ofwhich little is known.

In the schematic diagram of the set(Fig. 1) you will notice that the top of theprimary coil, at A, is connected to thebottom or end of the secondary coil atD. If these coils were regular solenoidsthis connection would cause a short circuit, and no signal would be received. Butthe primary and secondary are wound inopposite directions and then connectedtogether. This evidently prevents the shortcircuit which would occur if the coils werestandard selenoids. (Fig. 2) shows the coildetail and (Fig. 3) the photo of the coiL

Take a cardboard or other tubing 4"in diameter, and 4" long. Use No. 644"round head machine screws for your con-nections. Fasten a screw with a washeron both sides of the tubing, just even

FIXED STATIC COIL used by theauthor. (Fig. 3).

$

,4111

FIG. 4, panel view of the set when a vario-coupler was used. With fixed coil, omit

the dial at right.

with the top edge of the tubing. Turn thetubing around and on the opposite sidemeasure down 1 7/16" from the top edgeof the tubing and fasten another screw.These are the fastenings for your primarywinding.

For your secondary winding measuredown IA" from the top at the left side ofthe tubing, and fasten another screwdirectly opposite, and A" from the bot-tom of tubing fasten another screw. UseNo. 20 double cotton covered wire. Con-nect the wire at A and wind 20 turns andconnect to B on the opposite point of thetubing at the top. This completes yourprimary.

For your secondary winding, connectyour wire to the third screw, C, at theleft, and wind 40 turns, taking a tap every5 turns, 7 taps in all, and connect to D atthe bottom of the tubing. This completesthe winding of the secondary coil.

Connect the aerial to the stator platesof the condenser, Cl, and also to terminalC of the secondary coil, this is the onlyantenna connection.

Connect to crystal to rotor plates ofthe condenser, and lead to A of the prim-ary coil. Connect A of primary to D ofsecondary at bottom of coil and connectto last switch point. Connect switch armto B, to jack and to ground. Connect cat -whisker side of detector to other side ofjack. The fixed condenser C2 is shunted

LIST OF PARTSOne astatic wound coil L1L2.One .0005 mfd variable condenser, Cl.One .006 mfd. fixed condenser, CLOne 7x10" hard rubber paneLOne open circuit jack.One crystal detector.One spool Ys lbs. No. 20 DCC wire.One dial.One tap -switch (8 points, 2 end stops).

F G. S (top), the rear view of the Asta iocrystal set. The lower photo (Fig. 6)

despicts the variocoupler setacross the phones in the usual manner.the lap loops of the secondary are broughtto the switch points.

Fig. 4 is a photo of front of set thatbrought in KDKA from Washington,using a 4' variocoupler to wind the coilon. This set is mounted on a panel 6x10".

The condenser will tune stations vary-ing 100 meters on one tap of the switch.The second tap is best for station under300 meters with any aeriaL

The third tap is for 400 -meter stations,and the fourth tap for 500 -meter stations.The additional taps will bring in higherwavelengths. I use these extra turns toincrease volume.

When the short-wave antenna is usedthe input is reversed, that is the groundis substituted for the antenna. This re-verses the tuning and the switch taps in-crease from right to left. So used, thisset just goes to 550 meters.

Dill Bill Discussed;Senate Action Urged

WASHINGTON.Hearings on the Dill radio bill to give

the Secretary of Commerce additionalauthority to regulate radio were resumedin the Senate. Senator Watson, chair-man of the Interstate Commerce Com-mittee, is convinced of the urgent neces-sity for radio legislation this session ofCongress, and he is determined that hiscommittee shall report out some kind ofbill in time for consideration by theSenate.

First Show Is HeldBy Spokane Dealers

SPOKANE, WASH_One of the largest groups of radio re-

ceiving sets ever assembled at one timewas shown at the first radio show held atSpokane, Wash. Dealers confined them-selves to their particular sets and all call-ers had the benefit of expert informationon interference problems and other gen-eral radio problems, the dealers providinga booth for the Radio Listeners' Associ-ation.

HERMAN BERNARD. rarmsena allowRADIO WORLD. broadcasts every Friday at 7WGB3, Gimbel Bros., N. Y.315.6 meters. He discusses "What's Yewp. m.. from Qtr,315.6

Limes MI

1,[11-, 1 V 55 N.../ LW

Educational Use of RadioBy C. W. Warburton

Director of Extension Work, U. S. De-partment of Agriculture

seV HIS is Station KSAC, the Collegeof the Air, Kansas State Agricul-

tural College at Manhattan."This is the announcement for which

hundreds of folk all over the centralUnited States are listening at 7:30 eachMonday to Friday, when the Kansas StateCollege broadcasts its regular course ofeducational lectures. Similarly, other edu-cational institutions are extending theirfields beyond the college campus. TheKansas College, however, was one of thefirst to recognize the educational value ofradio and to make systematic use of it.

From the beginning of the school yearin September until late in the followingspring, a regular schedule of lectures isbroadcast to hundreds of listeners who areregistered for these courses. In additionto those who are registered, correspond-ence received at the college indicates thatseveral times as many listen in more orless regularly on the educational talks.The lectures cover a wide variety oftopics, such as crop and livestock produc-tion, dairying, poultry raising, foods andnutrition, household economics, English,chemistry, botany, zoology, and the sev-eral major engineering fields.

The Personal ContactThese radio lectures constitute a sort

of glorified correspondence course in thatthose who are taking the course have theopportunity to hear the voice and thushave, in a measure, the personal contactwith the teacher which heretofore hasbeen limited to the classroom. After eachlecture is given, mimeographed copies,with such additional tabular and illus-trative matter as may be desirable, aremailed to the registered listeners -in. Atthe end of the course an examination isgiven and those who show evidences ofproficiency are given a certificate. Insome institutions definite credit toward acollege degree is given for satisfactorycompletion of radio courses.

Registration for the radio courses givenby the Kansas State Agricultural Collegeduring the college year 1924-25 includes1,771 individuals registered for a total of11,431 courses. While the major portionof these individuals reside in Kansas ornearby states, the far-flung possibilitiesof radio are demonstrated by the factthat there were registrants from morethan 30 states, from several of the Prov-inces of Canada, and from Mexico. Thegrowing popularity of the courses is in-dicated by the fact that the total regis-tration was nearly double that of theprevious year, while the average numberof courses for which each individual reg-istered increased from 2.5 to 6.8.

One of the PioneersI have gone thus fully into the radio

courses presented by the Kansas StateAgricultural College because this institu-tion was one of the pioneers in the fieldand its faculty is exceedingly enthusias-tic about its possibilities. Kansas StateUniversity, the State University of Iowa,Iowa State College, Ohio State University,Michigan Agricultural College and Ore-gon Agricultural College are other insti-tutions which are giving regular coursesof instruction over the radio. An inter-esting feature of the programs of severalof these institutions is the half-hour ofopening exercises which they are broad-casting for schools. The State Universityof Iowa broadcasts opening exercises forhigh schools which are received by some200 of these schools. The Kansas StateAgricultural College broadcasts exercises

GILDA GRAY, popular dancer, writ-ing to Radio World as to the type ofprogram she would like to have,

every evening. (Foto Topics)

for rural schools and in one or two statesplans are under way for broadcastingmessages to schools by the state depart-ments of public instruction. One of thebroadcasting stations in Mexico is oper-ated by the .Secretary of Public Educa-tion.

Features Not NewThe utilitarian and educational use of

the radio is not a new thing. In fact, oneof the first public uses which was madeof radio broadcasting was the sending outof weather reports and storm warningsby the United States Weather Bureau. Alittle later the same means of giving wideand prompt distribution to market reportswas utilized by the Federal Departmentof Agriculture. Now the broadcasting ofweather reports is a regular feature of theprogram of many of the commercialbroadcasting stations, as well as of thosewhich are maintained by educational in-stitutions.

An interesting and useful type of mar-ket reports has been worked out by thePennsylvania State Department of Mar-kets and the Fruit and Vegetable Mar-keting Division of the U. S. Departmentof Agriculture. This is a consumer's newsservice, which consists of frequent radiobroadcasts from Philadelphia stations,which tell the housewife just what foodproducts are on the local market in quan-tity or in specially good quality. Coupledwith this is usually a brief talk by a homeeconomics expert on how to utilize mostsatisfactorily the articles of food discussedin the market broadcast. This kind of in-formation serves the consumer, in helpinghim to buy and utilize food products mostadvantageously, and at the same timeserves the producer by tending to preventmarket gluts and consequent ruinouslylow prices.

Scientific TalksMany of the commercial broadcasting

stations which are devoted primarily toentertainment features introduce occas-ionally, and in some cases regularly, edu-cational broadcasts. This is particularlytrue of stations which serve the more im-portant agricultural areas. They havefound it advantageous to introduce in theirprograms, in addition to weather and mar-ket reports, talks on a wide variety ofagricultural subjects. These are contrib-uted by members of the staffs of agri-cultural colleges or by the farm press,and by successful farmers and rural lead-ers. A feature of many broadcast pro-grams, particularly during the morninghours, is a talk to housewives.

A striking example of the educationaluse of the radio is the fifteen -minutepopular talks on scientific subjects whichare arranged by Science Service, an ad-

junct of the National Research Council,for broadcasting by one of the radio sta-tions at Washington, D. C. These talksare prepared by eminent scientists andconstitute a definite effort to present sci-entific facts to the public in an interest-ing and entertaining way.

Needs Textual AdjunctTo be most effective, radio lectures

should be combined with mimeographedor printed copies of the text, which aremailed to the listeners, together withsuch additional tabular and illustrativematerial as may be desirable. Some insti-tutions broadcasting radio courses mailcopies of the lectures to those who areregularly registered for them, just assoon as each lecture is completed. Otherssend summaries of the lectures at the endof the course, together with answers toquestions which have come in from lis-teners. It is manifestly impossible, how-ever, to register or to send the printedtext to the great majority of those whohear the lectures. It is equally impossibleto measure the benefits which will resultin a more broadly educated people andone which is better satisfied with its homelife, whether in the city or in the country.

While the agricultural colleges are find-ing the radio of particular value in reaching rural people, its advantages in an edu-cational way are not by any means limitedto this class of institutions or to farmhomes. The program manager of thebroadcasting station of one of the stateuniversities tells me that his stationbroadcasts courses in education, apprecia-tion of literature, history, sociology,journalism, political science, botany andzoology. He sees great possibilities forbroadcasting in other fields, such aspreciation of music, popular astronomy,economics and government. Incidentally,one of the most popular features of theprogram from this station is a Sundayevening half-hour of popular hymns.

A Glimpse Into the FutureWhat is the future of education broad-

casting? The educational use of the ra-dio is so new that, like other uses, noman can say what form it will take a yearor five years from now. Just as news-papers and magazines appeal to differ-ent groups of people according to thecharacter of reading matter they print,so each radio station is likely, it seemsto me, to build up a following accordingto the program it presents.

Like the magazines, most stations willhave to depend largely on advertising fortheir support, though this advertising maybe so carefully and completely sugar-coated as not to be recognized as such bythe casual listener. On the air, to aneven greater extent than on the printedpage, it is difficult to segregate advertis-ing from other matter.

If certain commercial stations of thefuture are to be devoted primarily to ad-vertising, they must carry a certain pro-portion of educational and entertainmentfeatures to maintain their following. Edu-cational features in such programs, how-ever, are likely to be more or less casualand incidental. The expense of provid-ing these features and the competitionwith advertising and entertainment islikely to cause them to remain a com-paratively minor factor.

On the other hand, radio broadcastinghas greatly widened the field of the col-leges and universities. They have readyat hand a large number of experts whocan provide educational programs at com-paratively little added expense.(Copyrighted 1926 by Stevenson Radio Syndicate.)

March 6, 1926 RADIO WORLD 9

Dah-Dit-Dah-Dit-Dah!By Irving Philip Wolfe

ZAPJ

8 CZA in Detroit informs me that thereis a bunch of Austrian hams. He hasgotten a list of them and it consists ofthe following:

AF, AR, AW, BE, BH, CP, DA, FG,FH, FL, HF, HI, HR. JA, JL, ICH, KK,LA, LM, LP, MH, NA, OA, OP, RF, RH,SF, SJ, SV, TA, TM, TO, TW, WA, WM.He doesn't know their wave, but he doesknow that they want QSLs sent toOesterreichischer VersuchssenderverbandKlubsaal des Hotel de France, Schotten-ring 3, Wien 1, Austria. The "Radio Ex-press" of the Hague is their officialmagazine.

*

Marcellus L. Jacobs of Culbertson,Mont., says that his spark coil CW outfithas a daylight range of easily 75 milesand a much greater nightime range.

* * *

1 AOA reports that the most consistent2s worked during the afternoon are 2 BMand 2 AX. He also says that the twosare the most courteous fellows to talk toon the air. The sixth district reports himas being one of the loudest stations onthe east coast and every one he worksgives him an R7 or an R8. He is using a250 -watt tube now with the WNP typecircuit.

* *

Mrs. 2NZ was asked why she didn'tlearn the code and get on the air as thefeminine department of the station. Herreply was that somebody in the househad to remain sane. Hi l

* * 52 ALS had the great honor of handling

the first official army amateur messageever to be transmitted in amateur com-munication. The message was a 50warder and was sent to him from 4 FXdown in Knoxville, Tenn. The purposeof this message was to determine whetheror not relaying was better than directcommunication on the army amateur 40 -meter band. ALS is using a 50 watterand has been reported in all parts of theworld.

* * *I have a few new QRAs, so better get

out a pencil and jot them down on callbook, om. John R. McKenna of 2805Eighth Ave., Astoria, Long Island, N. Y.,is using a UV 203a on 40 meters. He wasassigned the call 2AVB. Another newbrass -pounder is 2ARD. Eric Lutz, of924 Summit Ave., New York City, hasthat call. Another new second districtham is 2 ANX, J. Toman, Jr., 410 East17th St., New York City. His power is 5watts on 80 and 170 meters. A 450 voltmotor -generator supplies the plate juice.

*

I am informed through the first districtrepresentative that 1 AIV, the old-timecommercial, is coming down on 40 metersto help improve the QRM around New-port.

5 *

A new Q signal that might be put intogood practice is QTK. Whenever someham tells you that you are about R9pounding in all over the room just sayQTK and he will then proceed to blushwith shame. It all means that QTK is"Quit The Kiddin'." Hi.

* *I want more Calls Heard, gang. Atpresent there are just a few reporting.

Don't forget-the more the merrier. By

the way, if there are any new hams inany part of the world who see this or iftheir friends see it, just send in a cardwith news of the new stations. Alsoinclude with this the address of the newham.

* *

9 AML, G. N. Bragg, is now located atBlue Springs, Nebr. He is using 100watts fone and was reported in Kittaning,Pa.

5 * *

In regard to the Sixth.Annual Conven-tion of the Executive Council, SecondDistrict, which will be held March 10-13inclusive, one of the judges of the Broad-cast Receiver contest has been given toHerman Bernard, manager editor ofRADIO WORLD. He has also promised togive a talk on Trouble -Shooting in Broad-cast Receivers, Friday, March 12, at theshow.

The ERCO annual initiation will alsobe given on Friday evening. The ticketswill be $1.50 apiece and may be purchasedby addressing the council at its head-quarters, 74 Cortlandt St., New YorkCity. The sale of ERCO tickets will beclosed on Wednesday, the first evening ofthe convention, so you better grab onequick. The banquet will take place onSaturday evening, March 13. Ticketsfor the banquet are $5 apiece and maybe purchased either directly from head-quarters or through any of the officialsecond district clubs. The banquet ticketalso includes a "season" ticket to theshow and all activities, such as trips tolocal ham and broadcasting stations.Among the exhibitors at the show will beA. H. Grebe & Co., Cardwell, Hammar-land, Radio Engineering Laboratories,Bruno Radio Corporation, RB Radio Co.,Priess, General Radio, Powertone ElectricCo., and many other of the best knownand reliable manufacturers.

* 5 *2 AJE, of the Yonkers Radio Club, is

now slamming out a mean signal on 80meters. His DC note is a wow to copy.

* * 5

2 BLF is temporarily off the air. Hesays that the reason is his being QRWYLs so I expect him back pretty soon.Perhaps his "bug" decided that it wassending too many dots lately-or his"H" tube might have taken a short strike,you never can tell. Hi I

* *2 APV, 2 QH, 2 MA, and 2 BDZ band-

ed their interests together and are nowengaged in busin:ss.*

As you can easily see it is 3 CDQ, ourfriend from Washington, who has the pic-torial part of my article this week. 3 CDQis owned and operated by Miss ElizabethM. Zandonini, whose QRA is 3320 -19thSt., N.W., Washington, D. C. Miss Zan-donini has a 100 per cent American RadioRelay League station (emphasize on the100 per cent. and the Relay).

The transmitter at 3 CDQ consists oftwo 50 -watt tubes, using the standardHartley loose -coupled circuit. On 40meters .5 amp. is put into the antennasystem. The inductance used is an old200 meter coil, cut and spaced. The setis kept within the proper wavelengthband by use of a wavemeter calibratedfrom WWV's test signals. The wavemet-er has interchangeable coils and can beused from 20 to 161 meters. The receiv-er is a low loss Schell tuner also usinginterchangeable coils. It tunes from 35to 500 meters; loud -speaker volume isprocured from a two step audio -frequencyamplifier unit.

The power supply is the most interest-ing part of 3 CDQ. A 10 ampere West-inghouse Elec. Co. Cooper Hewitt mer-cury arc tube is used for rectification.This rectifier will be shown next week,and was installed by Donald Basim,

An excellent rectified AC noteis delivered from this type of power sup-ply.

Miss Zandonini is Radio Aide at the Bu-reau of Standards (NKF) in Washingtonand is one of the most active membersof the Washington Radio Club. Shewould be glad to supply the hook-up ofher rectifier and other equipment.

* * *

QST-QST-QST-de-2APJ-2APJ-2API -Don't forget to send those Calls Heard, newQRA's, bit of news and queries to 2API,Irving P. Wolfe, Amateur Editor, RADIOWORLD, 145 E. 45th Street, New York Cityor call 2API on the air, 40 or 150 meters.

THE amateur transmitting station of Miss Elizabeth Zandonini, Radio 3 CDQ,of Washington, D. C. On the table at the right is the receiving apparatus. Thechemical rectifier, located under the transmitter at the left, has been replacedby a new mercury arc rectifier. The new calibrated wavemeter can be seen atthe left of the transmitter.

10 IL A I) 1 0 \V OR I. 1) March 6, 1926

Wiring the Victoreen SetArrangement for First Detector

THE INPUT END of the Victoreen, showing how the antenna coupler is placed,how the grid leak -condenser unit is mounted and how the leads are brought from

the loop jack. The tuning condenser, CI, is shown at half setting.

[Part I of the 3 -part article on the con-struction of the Victoreen, an 8 -tube Super -Heterodyne, was published in the February20 issue of RADIO WORLD, while in the Feb-ruary 27 issue, Part II was printed. Follow-ing is the instalment dealing with the actualwiring. Trouble -shooting will be discussedin nest week's issue, dated March 6.]

PART Ill.AS efficient parts are used in the Vic-

toreen, the results obtainable fromthe completed set will depend largely onthe manner in which the receiver is wired.The wiring problem was simplified by thedetailed description of placement of parts,published last week, and which concernedboth the front panel and the baseboard.From that point forward it is simply amatter of connecting the wires properlyto the posts to which they should go, andthis is the burden of the present instal-ment.

Keeping the oscillator coil safely dis-tant from the radio -frequency trans-former (Type 160) is a good precautionand it is assumed this has been done, asdirected. While some other location ofthe oscillator coil would give fine resultsin many instances, it is better not to ex-periment with this, unless one is thorough-ly versed in Super -Heterodyne design.This advice is repeated so that the con-structor will not make a mistake whichwould necessitate rewiring much of thereceiver.

Options DiscussedThe wiring was done with Celatsite, and

an Acme 5 -lead vari-colored cable wasused to connect to the batteries. Thusno binding posts were employed, butwherever a connection was to be made tobattery, it was established directly, with-out passing through a binding post. Thatwas simply the method adopted. although

any who prefer to use a terminal stripmay incorporate that, too. It would haveto be added to the list of parts, not beinga member of the kit family.

Three more added starters should bediscussed. If the Kurz Kasch E-Z-Toondials are used it will be necessary to pro-cure two dial pointers. The ones usedare known as the Eureka.

The fixed condenser, C4, shown in theschematic diagram last week, is not apart of the kit, either, and would have tobe obtained additionally. It is not a nec-essity, but simply safeguards againstblowout of tubes should one accidentallyshort the stator and rotor plates of theoscillator condenser, C2. The value ofthis fixed condenser is .006 mfd., which istoo high to affect in any material way thetuning of the oscillator condenser. Do notuse a smaller fixed condenser here. Onemay see from a glance at the schematicdiagram (page 14 of the February 27issue) that should C2 be shorted, as de-scribed, the B battery voltage of 45would be placed on the tube filaments.This is because one side of the condensergoes to plate of the oscillator tube (a B+45 lead), the other side to A minus,through the grid coil L4.

The other added starter is a set of bat-tery cable tags.

Wiring DirectionsThe identity of the rheostats was es-

tablished last week, in respect to theirpanel location and function, hence it willbe assumed that the reader is familiarwith these points.

As the set will work right off the reel,if directions are followed, we will proceedon the basis of immediately turning outthe completed receiver.

First wire the A battery leads, especiallyso far as they concern direct current pur-poses. Run a spaghetti -covered busbar

lead, beginning 5%" from left and 2"from the panel rear, and going to 1A"from the panel rear. Looking at the rearof the panel, this lead is turned to theright until it reaches the switch, where itis soldered. The remaining open side ofthe switch goes to the left-hand side (orcenter) of each of the rheostats and tothe right-hand side of the "potentiometer,R3.

The A Plus LeadAs seven of the sockets are in a row,

spaghetti is scraped off one long lead,running about 18", so that the lugs atthe plus posts of these sockets may beturned up and the lead soldered to eachof the seven points, on the F plus wire.The oscillator tube is directly in front ofthe third intermediate tube (4), so the Aplus or F plus lead is carried from thepost on socket (4) straight to the corres-ponding post of the oscillator socket, thenaround to the left-hand side of the poten-tiometer and to the left-hand rear post ofthe oscillator coiL

Now return to the A minus lead andcarry the remaining sides of the rheostatsto the proper destinations. The right-hand rheostat RI, 30 ohms-still remem-bering that we are facing the back of thepanel-is connected exclusively to the firsttube socket's F minus post. The openside of the next rheostat, R4, 6 ohms,which is between the potentiometer andCl, goes to three F minus posts, one oneach of the three intermediate frequencyamplifying tube sockets (3), (4) and (5).The open side of the rheostat R6 (6 ohms)goes to three places, two of them beingthe F minus posts of the detector andfirst audio sockets, (6) and (7). The lasttube is taken care of through the fila.ment-control jack, J3. This jack ismounted with the springs on top, whichis the conventional style. The top springis joined to the common F minus lead al-ready established on two sockets, whilethe adjoining spring, second from top,goes to the F minus post of the finalaudio socket. The jack in question is thelower of the two that are mounted on thepanel, one directly above the other. Thetop spring is represented at extreme rightin the schematic diagram published lastweek, while the second from top springis next to it, or second from right. Thiscompletes the A battery wiring, on a directcurrent basis.

Next take care of the positive grid re-turns. These are two-the return of L2through L3, and the return of the inter-mediate frequency transformer that isjust ahead of the second detector tube(6).

Radio Frequency WiringThe bottom spring or lug of the loop

jack, J1, is connected to the rotor platesof Cl and to the rear right-hand post ofthe oscillator coil. The left-hand post al-ready has been connected to positive A.The F post of the final 170 transformer isconnected to A plus on socket (5 by bend-ing the wire to the right, then forward,then, for a 9" length, to the right, to meetthe lug on the socket. It is advisable to es-tablish this lead at this time, becauseotherwise difficulty would be met in locat-ing the grid leak condenser combinationor R5C6, according to the layout of theoriginal model.

Variable Grid ReturnsThe F posts of the other intermediate

frequency transformers are joined to themid -post of the potentiometer. This leadis carried directly toward you, in otherwords, at right angles to the panel, andis soldered to a lengthwise lead that joins

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12 RADIO WORLD March 6, 1926

Final Steps in the WiringB + and Potentiometer Leads

THE LOCATION of the by-pass condenser is shown, likewise the position of thegrid leak -condenser combination for the second detector. The B plus detector leadis in foreground, while the potentiometer midpoint lead, jutting toward you, isshown established to the F lead three of the medium frequency transformers. The

F post of the one at left goes to A plus, instead of to the potentiometer.

these three F posts of the transformers.All three posts are at top, left.

The G post of the antenna coupler,Type 160-the coil that has the word"coupler" on the casing and which hasthe larger visible winding-goes to thesecond from top spring or lug of J1. Thetop spring of J1, the loop jack, con-nects to the stator plates of Cl. One sideof the grid condenser C3 is soldered to thislead, too, so that the grid condenser,which has mounting clips for a leak, is atright angles to the baseboard. The otheror top side of this fixed condenser isjoined directly to the grid post of tube(1). The grid leak R3, which is 2 meg-ohms, is placed in the clips. The bottomlug goes to rotor plates of Cl and to therear right-hand post of the oscillator coil.The second from bottom lug of J1 goesto F of the antenna coupler.

Now for the remaining connections tothe oscillator coil. The P post of theoscillator socket (2) is connected (throughcondenser C4) to the stator plates of C2,while from P of the socket the lead iscontinued to the right, to the P post onthe oscillator coil (right front). This Ppost on the coil is shown at the lower endof L5 of the schematic diagram. The Fpost of L4, left-hand upper front of oscil-lator coil, goes to A minus, to the rotorplates of C2 and to C5. This fixed conden-ser, 1.0 mfd., has not been located, up tothis point, but it is between tubes (3) and(4) and is screwed onto the baseboard atright angles to the panel. The main Fminus lead, running h" away from thepanel, is scraped, to remove insulation, sothat the present connection can be madethereto and to the fixed condenser andthe coil. Now wire up six B posts. Theseare the plus posts of the four intermedi-ate transformers (upper right), the B plus

post of the first audio transformer andthe plus post on the oscillator coil, upperright. The oscillator plus B plus lead iscarried to a common point where thedown lead to the second inter-mediate transformer is joined to the hori-zontal B plus bus, and on the way issoldered to the remaining open side of the

The Audio

fixed bypass condenser already discussed.The posts of the medium frequency trans-formers are connected to plate of eachpreceding tube, and in each instance thislead will be 2" long or less. The G postsof the four transformers go respectivelyto the grids of the succeeding tubes, inthree instances, and these leads each willbe less than 1" long. The fourth case isthat of the second detector input, and in-stead of going direct to grid the G postof the coil connects to one side of thegrid condenser, the other side of whichcondenser, C6, goes to grid of tube (6).The leak, R5, is slipped onto the mount-ing with which this condenser is pro-vided.

Join the F posts of the two audio -transformers and let the lead stick outtemporarily 4 or 5" to the right. Thefixed condenser C7, .001 mfd., may beconnected right onto the lead, the otherside of the condenser to the plate post ofthe second detector socket (6). This putsthe condenser to C plus, instead ofmerely to A minus, as shown in the dia-gram. There is no difference in effective-ness.

The G post of the first audio trans-former is connected to the grid of the firstaudio tube (7), while the plate of thattube goes to the top spring of the topjack to your left (J2). The next adjoiningspring or lug, second from top, goes tothe P post of the final audio transformer,while the third one goes to the B pluspost of the final audio transformer. Thefourth or bottom lug is joined to thebottom lug of the lower jack and, lateron, to the B plus amplifier thefinal AF transformer goes to grid of thelast tube, while F already has been ac-counted for. The second from bot-tom lug of the jack J3 (lower one) goesto plate of the last tube (8).

The battery cable is yet to be con-nected. This is brought to the set at aboutthe point where the first audio trans-former is. The brown cable branches tothe left, as you look at the rear of theset, and is soldered to the lower lug ofthe lower jack at left. This is B+ ampli-

(Concluded on page 29)

Jack Connections

A VIEW of the Victoreen from the audio side. J2 is the top jack, J3 the lowerone. Notice the interconnection of the bottom lugs of both jacks. The B plusamplifier lead juts blackly to the right. The second from bottom lead of the lower

jack goes to plate of the last tube.

March 6, 1926 RADIO WORLD 13

FIG. 11 (top), close-up showing thelocation of the Input Power Trans-former method of socket upholsteryand rheostat for the two push-pullstages. Fig. 12 (center), view of rearpanel showing layout of parts. Thetransformers are held to the panel bybrass brackets 3" long. Holes havebeen provided in these brackets, sothat one end (at right angles) is fast-ened to the panel, and the other to thebases of the transformers, by using6-32 machine screws and hexagonalnuts. Fig. 13 (bottom) rear panelview showing layout and mounting.

[Part I of this article was published lastweek, issue of January 27. Part II, the con-clusion, folloWs.]

THEphotographs and captions pub-

lished this week clear up manypoints on the construction of the 4 -tubeDX Dandy and little more need be said,except on the point of aerial and groundconnections, and on tuning.

The aerial goes to the left-hand side ofcondenser 1, 2, 3 or 4, which, countingfrom top to bottom of the pictorial dia-gram published last week, means .0005,.0001, .00025 or .00001 mfd. The aerial leadis not shown in the diagram, but the wordaerial is printed, as it is understood thatthe connections are made to the fixedcondensers, through the jack posts. Twoseparate leads are brought from the aeriallead-in and a phone tip is soldered to eachterminal, as shown in Fig. 14. The otheror bottom piece in Fig. 14 is about 7"long and has a phone tip soldered to eachend. This is used as a jumper. It con-nects to 3 or 4 only or 3 and 4, never to1 or 2.

How Posts RunFigs. 17 to 20 show the fixed condenser

posts, for aerial connection in four in-stances and ground connection in two.The captions elucidate the usefulness ofthese points. Back to front in the speci-fied photographs, these posts run in num-erical order -1, 2, 3 and 4.

The circuit is a very simple one. Thefirst variometer, at left, is for wave-length tuning, the fixed condensers serv-ing an auxiliary purpose, governingvolume, selectivity, etc. The other vario-meter is a volume control, too, since it

The 4 -TubeDX Dandy

By Herbert E. HaydenPhotographs by the Author

FIG. 14 (top), the various connectionsto the set providing for certain limitsof wavelengths, and slight change incircuit from single to more selective,are arrived at by using an aerial cordwith two separate phone tips solderedto it. The leads on these phone tipsare about 6". Another piece of flex-ible silk covered wire about 7" longhas a tip soldered to each end. Thisis used as a jumper connection fromthe ground post to post 3 or 4, de-pending on the connection desired.Fig. 15, aerial connected for low -wave

single circuit to point 4.FIG. 16 (bottom), long wave for verysmall aerials. Notice jumper fromground post to post 4 of aerial jacks.

supplies the regeneration. It is connectedin the plate circuit of the detector tube.

How to Tune the SetThus, to tune the set, turn the wave-

length variometer to a given setting, andadvance the other variometer until a hissis heard in the earphones or speaker, butdo not turn the variometer so far that asqueal will develop. It may be possible toturn the wavelength variometer over aconsiderable portion of the scale or dial,without changing the plate variometersetting, to bring in a station. In that in-stance, however, the station most likelywould be a local one, and if the volume isnot sufficient, turn the plate variometerso as to supply more regeneration. Ifthat method fails to bring in your first

FIG. 17-Long-wave single circuitconnection. Both aerial tips used asshown. Fig. 18 (second from top),medium wave single circuit aerial con-nection. Fig. 19, long wave selectivecircuit. Aerial on post 1, jumper con-nection from ground to post 3. Fig.20 (bottom), low wave selective cir-cuit. Aerial on post 1, jumper on

post 4.

FIG. 21-The set is tuned, after aerialconnections are made, by moving thetuning variometer handle slowly overthe scale. Volume and regenerationare controlled by moving the vario-meter in the plate circuit toward an

oscillating condition.

station, try advancing the plate vario-meter slightly, each time you turn thetuning variometer to a higher wavelengthsetting.

As there are only two dials the set willnot prove a difficult one to tune. Onewill learn best from experience whichfixed condenser to cut in for a givenrange of wavelengths, and many of coursewill find that excellent results are pro-duced by ,leaving the aerial at a givenfixed condenser. This depends on aerialconditions, and as these differ, no set rulecan be established.

14 RADIO WORLD March 6, 1926A QUESTION and Answer

Department conducted byRADIO WORLD for Its Read-ers by Its Ing a Experts.Address Radio University,RADIO WORLD. KS Weal45th St.. N. Y. C.

Radio UniversityStator

A - A + -B B+FIG. 271, showing the special loop schematic diagram.

I WOULD be pleased to have a circuitdiagram illustrating how to connect aloop to a standard 5 -tube Neutrodyne re-ceiver. I understand an extra tube willhave to be employed.-Robert Johns,Unionville, Ill.

Fig. 271, shows the schematic diagramyou request. P2, the 400 ohm potentio-meter, is not an absolute requirement. Ris a ampere ballast resistor, providedthe -01A type of tube is used. This ofcourse depends upon the type of tubesused in the receiver proper. If 199 typetubes are employed, then a 199 type tubeshould be used in the loop unit. A .06ampere ballast resistor, better known asthe No. 4V-199 Amperite type, should beused. The condenser, which shunts theloop should have a capacity of .0005 mfd.S is a filament switch. The loop is of astandard size consisting of 14 turns ofNo. 18 bell or annunciator wire, woundon a frame 2 feet square. The antennaand the ground have to be disconnected,if the loop is to be placed into use. Avoltage of 67% should be applied to theplate of the tube.

I WAS going to build the 1926 ModelDiamond of the Air, but I notice that atleast 135 volts have to be placed on theplates of the amplifier tubes, in order toget the loudest signals. Now I have a BBattery Eliminator, which delivers only90 volts at maximum. Is it possible touse 90 volts on the plates of the tubes andstill get good volume, or will the volumebe poor?-A. M. Putlz, Sioux City, Ia.

The volume obtained will be good.

IS IT possible to place a fuse in serieswith the filament or across the filamentand the plate so that the tubes will besafeguarded against accidental blowouts,from touching the B battery and the Abattery. Where can it be purchased?-Fred Mucks, 160 East 25th St., Paterson,N. J.

Yes. See advertising columns.

I AM interested in the 1926 Model Dia-mond of the Air. Will it be possible withthis receiver to tune out the local stationWTIC, which has an output of 500 wattsso that I would be able to bring in WEAFWJZ and other stations in N. Y. City?(2) Where can I purchase the completekit so as to make this receiver?-EdwardW. Creighton, c/o The Phoenix Insur-ance Co., 30 Trinity St., Hartford, Conn.(1) Yes, provided you have a good an-

tenna, ground and the set is constructedstrictly along the lines of the description.(2)-See the advertising columns of thisissue.

I AM going to build The Set a BabyCan Build, described by Herbert E. Hay-den in Aug. 29 issue of RADIO WORLD.Instead of only having one tube, I wishto add a stage of audio -frequency ampli-fication. Can I have an explanation ofhow to do this?-Einar Ekdahl, P. 0.Box 140, Reidsville, N. C.

First disconnect the phones, which areinserted in series with the end of the tick-ler winding. Then insert a double circuitjack. The top terminal of this jackgoes to the end of the tickler winding.The next terminal from the top goesto the P post on the AFT. The thirdterminal from the top goes to the B poston the AFT. The bottom post goes tothe B+ Det. post. The G post on the AFTgoes to the G post on the second socket,which is going to hold the amplifier tube.The P post on this socket goes to the topterminal of a single circuit jack. Thebottom terminal of this jack goes to theB plus Amp. terminal. The F plus term-inal of this socket goes to the A plus Bminus terminal post. The F minus term-inal on the socket goes to one terminal ofa ballast resistor which is of the 99 type,passing .06 amperes. The other terminal ofthis resistor goes to the A minus term-inal post. A 4.5 volt C battery is insertedin series with the F minus post of theAFT.

I AM going to build a Browning -Drake4 -tube receiver. Now I woud like to knowif the placing of the parts would haveanything to do with regenerative effect ofthe receiver. That is, would the set oscil-late any more if the RFT and the 3 -circuittuner were placed nearer or further apartfrom each other?-Storey M. Jones,Presque Isle, Me.

By placing the RFT and the tuner atright angles to each other and about 6 in.apart the oscillatory action of the RFTand the detector tubes will be well undercontrol.

I BUILT a 1 -tube receiver using a Birn-bach 3 -circuit tuner. The primary of thistuner has 12 turns. The secondary con-sists of 37 turns. The ticker coil consistsof 30 turns. The primary and the sec-ondary are wound on a tubing 3Y, in. indiameter, while the ticker is wound on a

tubing 3 in. in diameter. A 199 type tubeis being used. The secondary is shuntedby a .0005 mfd. variable condenser. I donot hear any signals.

The hookup used is of a standard modelThe primary is in parallel with the an-tenna and the ground. The beginning ofthe secondary winding goes to the A minuspost and to the rotor plates of the var-iable condenser. The ending of the sec-ondary winding goes to the stationaryplates of the variable condenser and toone terminal of the grid condenser andleak. The grid condenser has a capacityof .00025 mfd. while the leak is of thevariable type from 1 to 10 megohms. Theother terminals of this leak and condens-er combination go to the G post on thesocket. The beginning of the tickler coilgoes to the P post on the socket. The endof this winding goes to one terminal ofthe phones and to a .001 mfd. fixed con-denser. The other terminal of this con-denser goes to the other teiminal of thephones and to a B plus post. The rheo-stat, which is of the 20 ohm type, is inseries with the negative leg of the fila-ment post. The plus post of the A bat-tery goes to the minus post of the B bat-tery.-Ernest Mosseau, 65 Main St., Co-hoes, N. Y.

Correct the secondary end that nowgoes to A minus, to A plus instead. Takeout the fixed condenser which is shuntedacross the phones. Test the tuner (pri-mary, secondary and tickler) leads forshorts or open circuits. Try another tubein the same position. Push the prongs ofthe sockets up, so that they make posi-tive contact with the tube terminals. Yourmethod of hooking up the set is all right.The tube may be dead (not blown out).

IT HAS been my pleasant experience tohave constructed the 1-A portable re-ceiver described by Herbert E. Haydenin the March 28, April 4 and the April 11issues of RADIO WORLD, which set is oneof the most efficient receivers that I haveever had the opportunity of constructing.I would like to build this receiver so thatit could be used as a portable. I wishto use a form 2% in. in diameter. Therotor forms will be 2 in. in diameter. No.26 double silk covered wire is to be used.How many turns shall be placed on thevarious forms?-A. M. Parker, 11623 88thSt., Edmonton, Canada.

The wavelength rotor E consists of 50turns. The modulation rotor F consistsof 25 turns. A consists of 25 turns. Bconsists of 25 turns. C consists of 13turns. D consists of 13 turns. L and Pconsists of 25 turns. F consists of 50turns.

I HAVE a 3 -circuit tuner made by For-man & Co., which I would like to use inthe 4 -tube Diamond of the Air, as de-scribed in the Jan. 23 issue of RADIOWORLD, by Herman Bernard. All thewindings are made with No. 32-38 Litzwire. The primary consists of 15 turns. Thesecondary consists of 42 turns. A form3 in. in diameter is used. The ticker coilwhich is wound on in. tubing, con-sists of 40 turns. Can this tuner be used?(2) How many turns should be placed onthe primary and the secondary windingsof a form 3 in. in diameter, to constitutea radio -frequency transformer which ismatched with the tuner? Leslie 0. Trem-bly, 62 Champion St., Carthage, N. Y.

(1) Reduce the number of turns on theprimary of the tuner to 10. The rest ofthe turns should remain as they are. (2)The primary of the RFT consists of 10turns. The secondary consists of 42 turns.Use No. 32-38 Litz or No. 22 double cot-ton covered wire.

IN REFERENCE to the 4 -tube Dia-mond of the Air, which appeared in theJan. 23 issue of RADIO WORLD, I have a 3-

March 6, 1926 RADIO WORLD 15

circuit tuner. The stationary form, whichis 3g in. in diameter, contains a primarywinding of 16 turns, while the secondaryconsists of 48 turns. The tickler form is2" in diameter and consists of 36 turns.No. 22 double cotton wire is used. I wishto make a radio -frequency transformerto match this tuner. How many turnsshould be placed on a tubing 3g in. indiameter to make this RFT?-W. J.Ewart, 4314 Courner St., Houston, Tex.

Reduce the number of turns on the pri-mary to 10. The primary of the RFTshould also consist of 10 turns. The sec-ondary of the RFT should consist of 43turns. The number of turns on the sec-ondary of the tuner should also be re-duced to 43.

WHAT IS the most efficient way ofplacing the primary in inductive relationto the secondary? 2) How many inchesseparation should there be between theprimary and the secondary winding if boththe windings are made on one form? (3)I live 134 miles from WBZ and amtroubled frequently by interference. Isthere any wave trap that was described inRadio World recently that when insertedin this receiver, which is a 5 -tube manu-factured type will cut out this station,without hindering the reception from anyother station?-Charles H. Jordan, 291Bay St., Springfield, Mass.

This depends on what part of the setthe primary serves to couple and otherfunctions. Placing the primary windingalongside of the secondary winding is agood way for general use. The primarywinding inside the secondary, at filamentends has a small edge over the side -by -side winding in some hookups. (2) A1/4" or 34" separation between theprimary and the secondary windings isall that should be made, unless the pri-mary has an unusually large number ofturns. (3) The regenerative wavetrapdescribed by John F. Rider in the Dec. 26issue of Ramo WORLD will cure yourtrouble.

WILL THE regenerative wavetrap de-scribed by John F. Rider in the Dec. 26issue of RADIO Woun work well in thestandard neutrodyne consisting of fivetubes ?-Dr. Ralph McWhirter, Allison,Ia.

Yes.

ON LOOKING over the Dec. 12 issue ofRADIO WORLD, I was quite taken up bythe B battery eliminator described byLewis Winner. I have an Elkay 5 -tubereceiver and I am somewhat puzzled asto how I am going to get the 2214, 90and 135 volt leads. At present, there areonly two voltages that can be obtained.I would appreciate the information onhow to obtain these.-F. Eugene Zeiner,250 West Ivy St., New Haven, Conn.

Instead of the resistance wire or sub-stance terminal going to the B plus post,place this post to an arm of another vari-able resistor, as B plus Det. This armconnection goes to the 90 minus volt post.The resistance post goes to the B plusAmp. or 135 volt post.

IN A 3 -tube regenerative receiver, using3 -circuit tuner with two stages of trans-former coupled audio -frequency amplifi-cation, will two 199 type tubes and one120 type tube give as much volume asthree 201A type tubes? (2) Will Bremer -Tully coils and condensers work all rightin the 1926 Model Diamond of the Air?(3) Can a tandem variable condenser besuccessfully used in the 1926 Model Dia-mond? (4) Will the volume obtained froma 3 -tube regenerator of the first mentionedtype be as much on DX stations as on1926 Model Diamond?-L. R. Ellerby,Burford, Ont., Canada.

(1) No. (2) Yes. (3) Yes. (4) No.The volume on DX stations when using

P G

c>

or p

Lc>B

FIG. 272, showing the 2 -stage amplifier, Mr. Elhdert requested.

the 1926 Model Diamond will be muchgreater than that from the 3 -tube re-ceiver.

PLEASE PRINT an electrical diagramof a 2 -stage audio -frequency amplifier,using transformers, telling the ratio ofthe transformers, type of tubes to use, etc.-Fred Elhdert, Rosedale, Ark.

Fig. 272 "shows the schematic diagramof the transformer coupled AF amplifier.The ratios of both these transformers areabout 3 to 1. The -01A type of tubeshould be used. A 10 -ohm, 54 -ampererheostat should control the filaments ofboth the tubes. About 90 volts should beplaced on the plates of both tubes. ACbattery voltage of 4.5 should be used. J1is a double circuit jack. The top prongof this jack goes to the plate post of thepreceding tube. J2 is a single circuit jack.A ballast resistor may be employed, in-stead of the rheostat.

* * *

I AM quite puzzled as to the exactplacing of the ballast resistors in the 1926Model Diamond of the Air. It states thatthree 'A ampere ballast resistance eachare used to control the RF, the detectorand the last audio -tubes, or R, RI andR7. Then it seems that a g ampere bal-last resistor should be used where R1 isplaced which is used here?-E. B. Polk,Cheriton, Va.

R1 is a g ampere ballast. R2 is the 34ampere ballast, as the filaments of firstand second audio tubes are controlled byit.

I AM building a 1926 Model Diamondand wish to use the Raytheon Plate Sup-ply Unit described in the Jan. 16 issue byLewis Winner. According to instructionsin other magazines the fact that the fila-

B+ Amp.

B+Det.

A+B-

A-

ment circuit of the receiver must begrounded is stressed upon. In the Dia-mond receiver, there is no direct connec-tion between the filament circuit and theground. Would it affect the circuit inany way if the filament circuit wasgrounded or is there no need to groundthe circuit at all?-W. J. Spellman, New-ark, 0.

By mounting the parts on a metal sheetas per Jan. 16 issue of Radio World, youaccomplish the same result as if the fila-ment circuit of the receiver were ground-ed. The metal mounting is even moreefficient than the grounding of the fila-ment circuit. What can be done, though,is to run the actual wire to the B minuspost.

I HAVE a 3 -tube receiver wherein thefirst tube is a regenerative detector, us-ing a Bremer -Tully 3 -circuit tuner, whilethe two stages of audio -frequency ampli-fication, using transformers, follow. Nowthe first tube works well, but when theloud speaker or phones are plugged in thefirst or second stage of AF amplification,a soft whistle is heard. When I put myfinger on the G post of the first trans-former it will stop, but if I put my fingeron the G post of the last transformer,the whistle gets louder. I tested my AFTfor shorts and open circuits and ant surethey are 0. K. How can I cure thistrouble?-Louis A. Sunde, R. F. D. 2,Box 3, Valley City, N. D.

Place a .001 mfd. fixed condenser acrossthe plate and the grid posts of the firstAFT. Try a 1 meg. leak from grid tonegative A battery in these tubes.

HERMAN BERNARD, managing editor ofRADIO WORLD. broadcasts every Friday at 7P. m., from WGBS, Gimbel Bros., N. Y. Raiz315.6 meters. He discusses "What's Yew.Problem?" Listen Int

Join RADIO WORLD'S University ClubAnd Get Free Question and Answer Service for the Coining 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 returnenvelope) and also put it in your queries and the questions will be answered the saunaday as received. If already a subscriber, send $6 for renewal from dose of presentsubscription and your name will be entered in the Radio University.

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

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City and State

16 RADIO WORLD March 6, 1926

Gimbel's TransmitterMoved to Better Site

BECAUSE it was hemmed in all all sides by skyscrappers, the steel frames ofwhich absorbed the power of their signals, station WGBS moved its transmittingstation outside of the center of New York City, to a little arm of land extendinginto the East River, at Astoria, Long Island. The station in its new location haswater on three of its sides and flat, open land on the other. A group of men is haul-ing up one of the 160 -foot poles which support the antenna system of the newtransmission location. studio and speech amplifier Gimbel Bros.Store, 33d Street and Broadway. Before this microphone, at 7 p.m. each Friday,

Herman Bernard discusses radio problems. (Kadel & Herbert).

So WGBS may reach a greater areaand may penetrate the blanket of steeand other air obstructions in New York

engineers of the Gimbel Brothers' Station1 in New York have moved the transmitting, plant from the congested district at 33rd

St., Manhattan, to a location in Astoria.The studio proper remains in the Gimbelbuilding and the programs are sent bylandwire to the new transmitter located inone of the best possible sections ofGreater New York for broadcasting pur-poses.

WGBS suspended operations on aTuesday night, after the broadcasting of"Charlot's Revue." Transmitting equip-ment was dismantled at once and the en-gineers worked the greater part of thenight moving the plant to Astoria. Wed-nesday and Thursday the staff was busypractically day and night getting the newtransmitter ready for broadcasting.

Friday morning early-shortly aftermidnight Thursday-WGBS put on atest program for several hours which re-sulted in reports coming in from all partsof Manhattan, the Bronx, Brooklyn,Staten Island and parts of Jersey, all ofthese mentioning an increase in receptionand an obliteration of "dead spots." Fromthe new location, a radiation one-third ofthe radiation from the old location, theincrease in audibility was found to be 325per cent. All reports mentioned an ex-cellent quality, the distant reports tellingof greatly increased volume.

The new transmitter is on a small pen-insula of Astoria, approximately opposite80th St., Manhattan, surrounded by wateron three sides. The site chosen is theresult of many months of careful experi-menting by the WGBS engineers. WGBSfor the time being is only broadcastingshort programs daily with a view to de-termining the results of the new location.

Aromatic Broadcaster

RUTH FALLOWS, former Folliesgirl, telling her "sisters of the radioaudience," all about the delightfulscents, which come from atomizers,which she holds in her hands. Thebroadcasting was done through stationWJZ, N. Y. City. It seems as if MissFallows is trying to transmit the odorin the same manner as her voice isbeing broadcast. Let's hope she

succeeds in doing this some time.(Kadel & Herbert)

Tone Quality Tests

A SPEAKER unit, with reed, as usedin cone speakers, may be placedagainst a bell -like vase for tonal

effect.

COMPARE this with the quality ofsound emitted from a wide bell, likethis glass vase, that acts in a com-

bination of cone and horn effects.

An Harmonious Four

THE Blue Ribbon Male Quartetteheard every Tuesday evening from8:00 to 8:30 through WEAF, WEEI,WFI, WCAE, WWJ, WGR and KSD.

clearly ova

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telegramsand Florid

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"My 10V.d. ol

irnsarnaougyi "Yen cgreatere

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Jacob A.

March 6, 1926 RADIO WORLD 17

nralley's Debut Delights NationMedal Award Broadcast

tl

Is

Ir

For Heroine's ComfortPresentation by radio of a medal

awarded for life saving was the ceremonyperformed for the first time between thetwo widely separated points of Ottawaand O'Brien, in northern Quebec, Canada,the radio serving as the link.

In her home at O'Brien, Mrs. K. G.Polybank, wife of a civil engineer in theservice of the Canadian National Rail-ways, heard the voice of Sir Henry W.Thornton, K. B. E., in Ottawa, tell thestory of the manner in which she riskedher life to save a friend's child. Beforethe microphone in CNRO, Sir Henry re-cited the facts which had stirred theRoyal Canadian Humane Society to makethe award of a medal granted only inmost meritorious cases where life hasbeen saved at personal risk.

It had been found difficult for Mrs.Polybank to leave her home and familycares, so radio was called to the aid ofthe interested parties. An official repre-sentative of the Canadian Royal HumaneSociety proceeded to O'Brien. When SirHenry had reached the appropriatemoment in his address the medal washanded to Mrs. Polybank.

The deed for which the award wasmade took place at Long Lac, Ontario,

(Photo by International Newsreel)Talky made her radio debut at Aeolian Hall,through station WJZ. Hcr four songs came

e air, and a few minutes after she concludedall over the East and as far South as Alabamagnu to arrive, bringing congratulations.Ictly a Kansas City night. Besides the 150d come all the way to New York to watch andear -old friend sing, there were 15,000 gatheredGall in Kansas City and a few thousand more in:k Building there, where another station con -1 wire from Chicago was broadcasting. As Miss

'her last song, "Home, Sweet Home," she pausedthen sent a greeting which spread over the

to her fellow -townsmen who had had faith in

thanks to all my friends in Kansas City," sheal support for more than three years has been

couragentent. And to my friends of the radioffectionate greetings."Talley was singing in the small broadcastingter sat just outside the door, her father stand -

third floor her fellow townsmen, who hadTalley sing "Caro Nome," "Comin' Thro' the

e poco fa" and "Home, Sweet Home" and ap-I her as she came down later on the arm offield, who led the delegation to New York.

MRS. K. G. POLYBANK in herhome receiving a medal for braveryat the psycological moment, the awardbeing broadcast from a station miles

away.

Canada, Mrs. Polybank plunged over-board from a motor boat to save theyoung child of a friend who had slippedover the side. Mrs. Polybank swam tothe child, maintained it afloat, divestedherself of clinging clothing and calmlyawaited the arrival of rescuers, beingpractically exhausted when reached.

Heats Furnace by Radio

A RADIO OPERATED FURNACE has been installed in the metallurgical sectionof the Bureau of Standards for the purpose of melting platinum and other preciousmetals. The wavelength of this high -frequency induction furnace is 1,000 meters.Louis Jordon of the Bureau of Standards is seen regulating the heat of the furnace.

(Harris & Ewing).

18 RADIO WORLD March 6, 1926

I Ile UM Comes.. an r.n,DW.,.JWan,D.nbutar snd Moe d *c.v.,

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52 consecutive issues SO%26 times consecutively or E. 0. W. one year 16%4 consecutive issues 10%WEEKLY, dated each Saturday, published Wednesday.

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

CI ASSIFIED ADVERTISEMENTSTen cents per word. Minimum 10 words. Cash with

order. Badness Opportunities ten cents Der word. 51A0minimum.

Entered a. second-class matter. March 23, 1922,the Post Office at New York, N. Y., under the id ofMarch 3, 1870.

MARCH 6, 1926

Pepping Up Tubes

IF a tube shows signs of decliningpep, burn it for an hour or more withthe A battery connected directly tothe filament. The photo shows a -99type tube being treated this way, a43¢ -volt C battery being used as theA battery. If -01A tubes are used,connect the A 6 -volt storage batteryleads direct to filament also. No Bbattery is used in either case. Thisremedy applies only to the XL thori-ated filament tubes. It will not work

on the -11 and -12 type tubes.

Sir Eric DrummondLinks Radio and PeaceBy Eric Palmer

Freed -Eiseman Radio CorporationStatesmen of the world are striving not

only to bring about lasting peace amongthe peoples of mankind, but with broadervision than ever before in history areseeking to effectively promote the age -long crusade against ignorance, bigotry,and disease, aided by the right-thinking,public-spirited private citizens of everycountry, whose wealth is being con-tributed to the great cause.

It was my privilege and pleasure tohear such encouraging words at the beau-tiful palace in which the experts of theLeague of Nations are studying theseproblems, in conjunction with represent-atives of all member -nations and withdistinguished economists, scientists andphilanthropists of the United States.

Of especial interest to me, as semi-offi-cial representative of the American radiopublic in connection with the recent in-ternational tests, was the statement ofSir Eric Drummond relative to the vastlyincreasing importance of radio in carry-ing on the great work, which regardlessof all political considerations, meets withuniversal approval.

Sir Eric truly remarks:"All we can say at the moment is

that we are at the beginning of a newera whose potentialities we can hard-ly guess l"Sir Eric dictated a statement of

tremendous interest to the radio listeners(and probably everyone else) in everycountry. Before doing so he pictured hisown thrills at hearing song and storyover the ether and appearing before themicrophone. In one instance he reachedthe Lapps in Northern Sweden.

Sir Eric's StatementThis is what the Secretary -General had

to say on the general subject of wirelesscommunication:

"Radio and the League of Nations areboth in their youth. They were born atapproximately the same time, and aregrowing and developing on somewhat thesame lines. Assuredly their fruitful co-operation will make for the peace of theworld.

"How rapidly civilization has travelledOnly a few centuries ago Columbus tookthree months to reach America. A cen-tury ago it took weeks to send news tothe Far East. Today information can beput on the air in London, received inNew York, re -transmitted and heard inLondon in the space of seconds.

"It is not easy, even for those whoserve the cause of peace, to realize theenormous new force that now makes forbetter understanding between peoples, onwhich peace ultimately must depend.Before it, distances and time almost ceaseto have importance. People hear of eachother and know each other. Before suchcontacts, war recedes to a distant back-ground. The full development of radiomust render international co-operation,and therefore the task of the League,infinitely easier.

"Up till now, the League of Nations hasperhaps hesitated to take up any posi-tion with regard to radio. The scienceis so new and the developments so rapidthat there has been a natural tendencyto wait until the situation becomes clear-er. Despite this, however, the League isfollowing developments with the utmostinterest and sympathy.

"The first incident involving the good

relations between nations, in which radioplayed its part with the League of Na-tions, was in connection with the recentGreco -Bulgarian frontier crisis. At thattime, hours before word 1d appearedin the Press, wireless information waspicked up in Geneva which gave Leagueofficials the first intimation they had hadof the seriousness of the crisis and allowedcertain preparations to be made whichmeasurably advanced the peaceful actionof the League. The value of a few min-utes of time in such a crisis can be fullyapreciated if I say that the necessarytelegrams, sent because of League inter-vention, instructing the opposing forcesto cease any hostile action, arrived lessthan two hours before the moment whena clash would have occurred.

Instantaneous Information"The League's second use of wireless

is in the establishment, for the first timein history, I believe, of an almost in-stantaneous information service wherebythe outbreak of plague or other seriousepidemic disease in any Far Eastern portis immediately made known to all neigh-boring administrations, who are thus puton their guard against any ships fromthe danger areas. Under this system allFar Eastern port authorities send in regu-lar reports of diseases to a central Leaguebureau created at Singapore with the aidof the Rockefeller Foundation. Thesereports are each week brought togetherinto one, telegraphed to the French wire-less station at Saigon in French Indo-China and from there broadcast through-out the Far East and wirelessed toFrance, telegraphed to Geneva, and inturn distributed through the Europeanports. Thus an opportunity is affordedto check the spread of disease almostfrom its source.

"Thirdly, this year for the first time,certain speeches at the Assembly of theLeague of Nations were broadcastthroughout Europe. The Prime Ministerof France, Monsieur Painleve, made hisopening speech not only to the Assembly,but to many thousands of people wholistened in in other countries. Sir AustenChamberlain, British Foreign Secretary,was also broadcast and there can be littledoubt that as the years go on more andmore of the debates will go out over theair.

"One problem which occupies us at themoment is the provision of proper wire-less transmitting facilities for the newAssembly Hall. This building, which isbeing planned for a capacity to accom-modate the representatives of 65 nationswith some 1,000 journalists, will undoubt-edly be the centre of some of the mostimportant of international debates.

"The future of radio is a matter onwhich speculation can run wild. I myself,however, can foresee the day when manyLeague conferences and debates will beput forth on the air; when many impor-tant declarations will go forth fromGeneva; one can even imagine that extra-ordinary sessions of the Council mightbe held by direct radio between states-men in different capitals. We can reallyhardly estimate the change that may bemade in international relations if peoplein various countries become accustomednot only to the thoughts but even to theactual voice of the statesmen of othercountries. All we can say at the momentis that we are at the beginning of a newera at whose potentialities we can hardlyguess."

March 6. 1926 RADIO WORLD . 19

Diamond Efficiency DataBy Herman Bernard

Associate, Institute of Radio Engineers

THE radio public is becoming ex-tremely critical. That is a healthy

state of mind. When the public wants onlythe best, and that to the fullest degree,then those serving them are spurred tomeet the demand, otherwise radio and allelse with which the public is concernedmight slump into a slothful state.

Courtesy vs. WantonnessTake the 1926 Model Diamond of the

Air, for instance. Some readers of RADIOWORLD and other publications may havesensed that a few words are being pub-lished on the subject of the Diamond."Radio in the Home," the handsomelyprinted and attractively edited product ofH. M. Neely's brainy work, in its Februaryissue published an original article on howto build the Diamond, and gave morethan generous credit to RADIO WORLD forthe design and popularization of the cir-cuit. But the "Radio Review and RadioListeners' Guide and Call Book," forMarch, the newly consolidated product,reprinted from RAmo WORLD, word forword, John F. Rider's laboratory analysisof the Diamond, and even published phy-sical cuts loaned to it, then purposely (ac-cording to an editor's admission) omittedany credit line, thus making it appear thatthe matter was original with "Radio Re-view." Although no trace of credit oracknowlegment is given to RADIO WORLD"Radio Review" had no reason from pastexperience to be so offensive, althoughno hard feelings are harbored on this side.

The Philadelphia Enquirer is publishingconstruction data on the Diamond, so arethe Bridgeport Evenings News and othernewspapers. The N. Y. Herald -Tribunepublished such an article a few weeks ago.These papers are using original articles,exactly following, however, the circuitas designed by me and popularized byRADIO WORLD, and it is comforting to seesuch a good hookup receive so much re-spectable attention.

Reasons For VarietyHowever good the hookup is, some per-

sons will build the set and fail to get allthe results that they hoped for. As waspointed out before, against the barrier ofscreened location, or an otherwise poorreception point, the Diamond has nothingto offer more than the run of receivers.In certain steel -walled apartment houses,in mines, in hollows of the countrysidewhere iron ore abounds, and amid similarconditions, poor reception may be ex-pected. Fortunately nobody has yet re-ported that he could not hear anything onhis Daimond, due to location trouble, al-though a few complained of poor volume.In one instance this was due to the con-structor having mistaken the primary ofhis audio transformer for the secondary --although they are plainly marked and thetextual directions identified these mark-ings no less emphatically than did themany wiring diagrams. So he had a step-down transformer. If volume was low,what else was he to expect? The con-nections thereupon were reversed andnow the fan is the contented owner of aset that gives all the volume that hisvoracious ears demand.

The New Ballast HookupSince its inception the 1926 Model Dia-

mond has undergone no wiring change,except that the Amperites were re-arranged, so that four ballasts were used,where there were only three. The book-let on how to build the set deals with the

newer hookups, which is the same onepublished last week on page 21 of RADIOWORLD. To clear up the matter for anywho may be trying to follow a previousdiagram, the following list is given:

R is a No. 1-A Amperite and controlsonly the RF tube.

RI is a 1-A Amperite and controls onlythe detector tube.

R2 is a 112 Amperite and controlsBOTH the first and second audio tubes.

R7 is a 1-A Amperite and controls onlythe final audio tube.

This arrangement only affords greaterflexibility. The last audio tube may be apower tube that draws .5 ampere at 6volts, in which case short-circuit or omitR7. If a 112 power tube is used in thelast stage, R7 should not be the 1-AAmperite but should be, like R2, a 112Amperite. The fact that the 112 Am-perite is used for R7, although govern-ing only one tube here, is due to thedoubled drain, the -01A tubes drawing25 empere at 5 volts and the 112 twiceat as much at the same filament voltage.

Moreover, if the audio tubes are ex-tinguished, for detector listening alone,the RF tube still has the correct andunchanged filament heating.

B Battery VoltagesThe B battery voltages are important.

The higher the voltage on the RF tubeplate the greater the tendency to oscilla-tion, until the point of paralysis is ap-proached or reached. Usually 67,14 voltson the plate of the RF tube will do verynicely, while the detector plate will stand45 without any trouble. B plus amplifierhad better be 135, which means three 45 -volt B batteries in series connection, butif only 90 volts are available, then getalong with that. The volume will not bemuch less, but the tone may not be quiteso good.

Synchronized TuningThe two dials used for wavelength tun-

ing-those that actuate the variable con-densers-may be made to read in step,but in most cases there will be a diverg-ence at first, however slight, due to thewiring, the plate capacity effect, etc. Thiscan be remedied. Take off half a turn ata time from the coil tuned by the dialthat gives the lower reading.

It is assumed that lower numbers on thedial represent lower capacity setting, butif the low readings represent the higherwavelengths, then remove turns from thecon coil tuned by the dial that gives thelower of the two readings for the samestation.

Sometimes a fan inadvertently uses acoil intended for a .00035 mfd. tuningcondenser, in conjunction with the pre-scribed .0005 mfd. condenser in the Dia-mond. The other of the two coils usedis all right. Immediately the fan notes awide difference in dial readings, also ischagrined not to be able to receive thelower wavelength stations. By takingturns off the oversized coil, or putting ina new coil of the right size, his problemis solved.

One man wrote me a bitter letter, say-ing he had built the Diamond because hehad read of the wonderful results ob-tained by others. His complaint was thatthe dials did not read together, but werefrom 3 to 7 degrees apart, although hecould tune from 180 meters to 555 meters(I) Also all he was able to get withplenty of volume on the speaker was aconsistent 750 -mile range ( H) He hadan 8 -tube Super -Heterodyne once thatcould not get that far, he admitted (Ill)

How to Get DXWhile remarkable instances have been

bridged by the Diamond, one must notexpect Coast -to -Coast reception. Locationhas more to do with distance traversalthan anything else, granting the set isproperly made of good parts and thetubes, batteries, aerial and ground are incondition. Next comes the ability to tunein DX, which is a thing personal to theset owner or operator, and this ability isacquired only by experience. It does nottake months, sometimes not even weeks,to acquire, but any one possessing a Dia-mond or any other set should give it atwo or three -weeks trial before passingjudgment. This is said in behalf of allreceivers, home-made, factory made ormade for you by some service man.

Safe and Sane SetThe Diamond hookup is a tried and true

one, embodying nothing fantastic or theo-retical. Its only departure from electricalconventionalism is in the absence of anyrheostats, it being assumed that circuitdesign should start with the filaments ofthe tubes heated at the specified voltagethat the manufacturer has spent thou-sands of dollars to confirm. That is 5volts for the -01A. Few circuits everhave been published omitting a bandrheostat from a detector stage, althoughmany omit it from RF stages more criticalthan the detector stage as to filamentheating. Another departure in the Dia-mond is mechanical rather than electrical-the scheme for immediate availability ofthe Diamond audit in conjunction withany other tuner the fan may be workingon. How often have you longed to havean audio hookup at hand for some 1 -tubeor crystal set you've just made! Whenyou build the Diamond you have a 2 -tubeset (the detector output), a 5 -tube setand also a 3 -stage quality audio -amplifier,each separate, yet all in one

GET THE OFFICIALBOOKLET ON HOW

TO BUILD

Radio World's 1926 Model

DIAMONDOF THE AIRThe test of the official Diamond bookletwas written by HERMAN BERNARD,designer of the 5 -tube cir-cuit wixich offers the most

50cc selectivity, volume, ton,quality and DX. Price, pr Cropy

CERTIFIED BLUEPRINT

FREE it1 every NPY OF THE OFFI.CIAL Booklet. glamors 'N-estsrs is every Ifeeile1 sad

every bieenrInt. Beth sent FREE to enr verb/subseribers.

News and Radio Dealers: Send for Whole-sale Prices. Order direct from AmericanNewe Co., Inc., 131.Varick St. N. Y.or American News Co. Branches.- -RADIO WORLD, 145 W. 45th St, N. Y. C.

Enclosed find SOc. Send me copy officialDiamond Booklet with FREE blueprint.Or both free with WOO for yearly sub-scription.NAMEADDRESSCITY STATE

THE 4 -TUBE DIAMOND OF THE AIR. byHerman Bernard, appeared in RADIO WORLDdated Jan. 23. I5c. per copy, or start subscriptionwith that number. RADIO WORLD. 145 W. 45thSt., N. Y. C.

20 RADIO WORLD March 6, 1926

KITS -KITS -KITS AND STILL MORE KITSThe Demand for the 1926 Model

DIAMOND OF THE AIR KIT.....S35.00

Each kit is com-prised of partswhich were spe-cially chosen byMr. Bernard onlyafter months ofe x p erimentation.The boxed andsealed kit containsparts which func-tion in completeharmony, giving abalanced receiverthat has proven itsworth to thou-sands of buildersall over the world.Each unit is care-fully tested beforebeing packed forshipment so as toavo'd any annoy-ances on the partof he purchaser.

Is Exceeding Our Wildest Expectations. The Country Is Going DIAMOND Crazy!Recognition Like This Must Be Deserved!

All pmts down to the last nut and bolt are included m each sealed kit as shown In this photograph.

The Diamond ofthe Air circuit iscomparatively newand was first pre-sented by Mr.Herman Bernardonly a short whileago. In that timeits fame hasspread n o t onlythroughout t h i country, but allover the world aswell. Radio ex-perts and engi-neers were quickto recognize a cir-cuit far betterthan the average,which accounts inevery way for thetremendous popu-larity of this cir-cuit.

We are pleased to announce that each kit will contain Sidney E. Finkelstein's special 16-page booklet, with a new full-size blueprint, which gives all data necessary for the con-struction, care and operation of the Diamond of the Air.

supply set builders with a copy at 50 cents each.

Folks! Meet Mr. HermanBernard, brilliant manag-ing editor of RADIOWORLD, one of whoseoutstanding achievementswas the designing andperfection of the 1926 Mo-del Diamond of the Air.

B. C. L. SPECIALA Combination Loud Speaker and Lamp

In the living room of the up-to-date homethe common loud speaker is quite unsightly.and therefore we asked one of the leadingmanufacturers oftable lamps tomake for us aspecial lamp whichcan be used as alaud speaker. Theloud speaker unitcan be inserted inthe bottom of thelamp, and the lilyshaped stand hasall the qualities ofthe best loudspeaker.

It is suppliedwith fancy silkshades in blue,gold, and old rose,with fringe tomatch. Someshades are round, some oval and others havepleasing odd designs.

They are all one price and in orderingplease state your preference.Combination Loud Speaker andLamp $10.50Combination Loud Speaker and Lamp withBaldwin Loud Speaker Unit and $15.45Cord

OfficiallySealed Kit for

The 1926 Model

Diamond of the AirUsing Parts Specified by

This seal, which bears thesignature of HermanBernard, is your guaran-tee of a receiver that isequal to if not better thanany 5 -tube set on the mar-ket. Insist upon this sealwhen purchasing your kit.

Just off the press-RADIO RESEARCHES, an interesting monthly bulletin In booklet (man containing a blueprint issued fromthe reports of the Laboratory staff of the Bruno Radio Corp. With each purchase of five dollars or over a free copy ofthis booklet will be given. Single copies 10c each.

The following pages will show the confidence of leading manufacturers whose parts were selected for usein the Boxed and Sealed Diamond of the Air Kit. You may see a completed Diamond on display at theNew York Radio Show, held at the Hotel Pennsylvania, beginning March 8, at Booth No. 13.

Write for FREE Catalogue!

B.C.L RADIO SERVICE CO., 221 FULTON STREET, N. Y. C. =VI

March 6, 1926 RADIO WORLD 21

`.,*441111111RW 7;//.. _,

,

k74,1:0ZiaN ,%

!ciTLI" '

MacMillan reediv--- d 'dabswith ThordarsonTransfoi nerd

If you were commissioned to explore the polarregions, you too would be very particularto select the best equipment - especially inradio, your sole means of communication./14.7i4

"rn C

ci0die

'Ledo,GyoBE

DeresnadyneADLER-ROYALMURDOCKMU-RADValleg

Silver -Marshallu2ARKA

11LTIVJDXRECNewpOrt

LgICHNUNN-LANDONKUSTOMBILTand

many othersuse

THORDARSON Super AmplifyingTransformers - the identical

transformers sold by dealers every-where and used in a majority ofquality sets-have been the exclu-sive choice of MacMillan on hisArctic expeditions.

Surely no greater tribute can bepaid to the actual supremacy ofThordarson Transformers, productof the world's oldest and largestexclusive transformer specialists.Faultlessly they amplified programsand messages from great distanceson the 1923-1924 expedition - andcame back "as good as new."Equallysuccessful was their performanceon the last expedition.

The wisdom of MacMillan's choiceis further confirmed by the fact

The Thordarson"Autoformer "All Fre-QuencyAmplifiers are our latest develop-ment. They amplify clearly the lowestas well as the highest notes of anyinstrument. An adaption of impedances,resistances and capacities. Write for the'larlaAutoformer Hook-up Bulletin-it's free.

that year after year, leading buildersof fine sets- makers of fine instru-ments especially noted for distanceand superb tone qualities-use moreThordarsons than all competitivetransformers combined.

Standard in the"Diamond of the Air" Kit

Thordarson iu Amplifying Trans-formers have also been chosen for the"Radio World's" famous INS DIA-MOND OP THZ AIR kit, describedby Radio World as "the hest receiverfor home construction"-and, therefore,worth of the finest audio frequencysmp tion to be had.

Thordarsons cost more to build -but no more to buy. Dealers every-where. Interesting bulletins on

amplification mailed free.

A utoforrners are S.5 each. Other Thor.darson Radio Transformers: Audio Fre-quency(subpanel or top mounting types),2-1, 5; 3112-1, $4; 6-1, $4.50. POEM"Amplifying, $13 the pair. InterstaitPower Amplifying. each $8. If des!cannot supply, order front us.

111ORDARSON ELECTRIC MANUFACTURING CO.Transformer spectalzsts since 1895

WORLD'S OLDEST AND LARGEST EXCLUSIVE TRANSFORMER MAKERSChicago. U.S.A.

ORD SSuperAMPLIFYING TRANSFORMERSStandard on the majority of quality sets

22 D 1 RI, I) March 6, 1926

46

0" Quartzite InductancesThe most efficient coils of theirtype made. The heart of the 1926

Diamond of the Air, chosen by Herman Bernard forhis circuit after exhaustive tests for comparativeefficiency. This is the Matched Pair of Bruno Coils Used in the

Bruno "Mr interstage couplerwound on quartzite glass rods withnewly designed tickler, giving mnyl-mum efficiency on all wavelengths.Tunes with .0005 condenser and cov-ers range of from 175 to 575 meters.Price $5.50

Diamond of the Air Circuit

The inventive genius, Mr. William A. Bruno,is busy in his laboratory, which is a sure signthat new and far more efficient apparatus thanhas appeared on the market up till now will beproduced. Among the items upon which Mr.Bruno is devoting much of his time is a newcondenser which is bound to make an instant"hit" with the radio fans who appreciate effi-cient apparatus. It will pay you to watchclosely the developments of Mr. Bruno's work,and these will be announced in advertisementswhich will appear shortly.

In order to keep the fans who are interested,informed more closely of Mr. Bruno's work,a monthly bulletin, known as RADIO RE-SEARCHES, will be issued at 10c per copy.

Trade MarkReg. U. R.

Patent 011es

Bruno "55" or "99" R.F. coil, whichis matched to tune with the Bruno"99." Also wound cos quartziteglass rods, which insures minutelysmall losses. The primary is greencolored and the secondary la sorange color, giving this coil ahandsome appearance. Price Sill

BRUNO RADIO CORP., 223 FULTON STREET, N. Y. C.Philadelphia Office:

611 Widener BuildingDetroit Office:

159 E. Elizabeth StreetChicago Office:

337 W. Madison StreetSan Francisco Office:274 Brannon Street

"Send Me AnotherBRETWOOD Variable Grid Leak"

'Thank you for introducing me tothe Bretwood Variable Grid LeaklI have installed one in my ThreeCircuit Tuner according to yourinstruction and find that it doesall you said it would and more.

S. R. HOBBS,180 Quincy St.,Brooklyn, N. Y.

This leak is used in King

Specifiedfor theDiamond ofthe Air

The grid leak I sent for arrivedand has been installed in a 4.tuberegenerative set. 1 have triedthem all. but have never had thepleasure of a real grid leak before.It is just a wonderful little in-strument.

F. K. WEISER,Haskell, Oklahoma.

George's Palace and by the U.

Ciridleak received and tested out,and find it is the only variableleak I ever used that is reallyvariable.

Enclosed find $1.50 for whichplease send me another one.

F. E. STALTON,Box 240, Ardmore, Okla.

I think it is about the best gridleak I have ever used. Have madequite a few sets and this beatsthem all. Get DX very plainlyand clearly.

WM. HEBERSON,2510 N. Franklin St.,

Philadelphia, Pa.

S. Shipping Board: over 270,000 sold in last four months

Price, $1.501/4 to 10

Megohms

Bretwood, Ltd., London, Eng., Sole Patentees and Owners

More DX, Clearer Reception, Smoother Control in Regenerative Sets AssuredThe Bretwood Variable Grid Leak may be installed in any set in five minutes by single hole panel mounting.

The North American Bretwood Co., 145 W. 45th St., N. Y. CitySole Distributors for United States

Canadian Distributor, Radio, Ltd., Phillips Square, Montreal

NOTE TO RADIOMANUFACTURERS

Write for Wholesale RatesA set with a FIXED Grid Leak may

work perfectly where tested, while it needsa VARIABLE Grid Leak so that set maybe adjusted to the locality where used.

THE NORTH AMERICAN BRETWOOD CO.,145 West 45th Street, New York City.Gentlemen: Enclosed find $1.50 for which you will please send me one Bretwood Variable GridLeak prepaid. Satisfaction guaranteed or my money back after trial within ten days of receiptby me.NAMESTREET CITYSTATE

March 6. 19.26 RA 1)10 WORLD 23

In the Famous"Diamond of the Air"

Write today

for FREE

Hook -Ups

TE1=z, EG. U.S. PAT. OFF.

The "SELFADJUSTING"RheostatInsures Perfect Automatic Tube -ControlBecause AMPERITE-Sold Everywhere

$1.10 complete

with mounting

(in U. S. A.)

1-Eliminates Hand Rheostats, there-by simplifying control.

2-Permits use of the latest types oftubes or any combination of tubes.

3-Simplifies and reduces set -wiring,thereby making for greater com-pactness and avoids losses.

4-No moving parts, hence no grind-ing noises; clear and full tones.

5-Prolongs tube -life by keeping fila-ments at a constant temperature.

6-No filament meters needed.7-Brings the most out of each in-

dividual tube-automatically-noguessing.

8-Makes every set -owner a masteroperator, no knobs to turn.

For the new tubes:Amperite No. 112-for the UX-112 and CX-112Arnperite No. 120-for the UX-120 and CX-120

-1W2lc/jail Compaliy.Dept. R.W.-16 50 Franklin Street New York City

Be sure that the set you buy orbuild is equipped with AMPERITE

Manufacturers of

TUN 1TE

t

24 RADIO WORLD March 6, 1926

SPECIFIEDFOR THE

"DIAMOND OF THE AIR"

CIRCUIT

EROVox

FIXED MICA CONDENSERS - BY-PASS CONDENSERS

BUILT TO BE BETTERAEROVOX WIRELESS CORP., 489-491-493 Broome St., New York City

Branch OfficesChicago, Ill. Cincinnati, 0. St. Louis, Mo.53 W. Jackson Blvd. 304 Palace Theatre Bldg. 1409 Syndicate Trust Bldg.

Boston, Mass. Los Angeles, Cal.104 Portland St. 324 No. San Pedro St.

STREAMLINEThe Straight -Line Frequency Condenser of Unfailing Per-formance. Enables tuning from 175 to 560 meters.Logging is Made Easy. Even a Baby Can Tune a Set That UsesStreamline Condensers.

.00025 $2mfd. .175 $2.25 .0005

mfd. $2.50The Streamline Condensers are officially certifiedfor use in RADIO WORLD'S 1926 Model Dia-mond of the Air.

Streamline Low -LossStraight -Line Frequency Kit

$7.50

Dealers, write in for proposition.

Distance and Volume at Your Command IBuild a Tuned -Radio -Frequency Set,Using the Streamline Kit! Coils and.00035 mfd. Condensers positively Low -Loss!(With Three Bruno Slo-Moshen Vernier

Dials, $12.50)

Enclosed and $, for which send

II

me at once--

Streamline SLF laud radio frame., kitStreamline SLF tuned RP kit, with Bruno( Sio-Moahen Dials.

I Streamline SLF madame.; capacity

Name

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CIO But,

Rttr;10 CO.213 FULTON STREET

,Xew York City

March 6, 1926 RADIO WORLD 25

KURZ-KASCH eArt.stocratChosen for DIAMOND OF THE AIR KIT

Moremanufac-turershaveadoptedKurz-Kaschproductthan allotherscombined.

KURZ-KASCH ARISTOCRAT DIALThe supremacy of Kurz-Kasch Aristocrat dialsis further exemplified by the choice of AristocratDials for the famous "Diamond of the Air" kit.The beauty of workmanship-the care in mould-ing-the expert mould making-all combine tomake Kurz-Kasch Aristocrat dial the choice ofthe big majority. The famous Kurz-Kasch splitbushing method of mounting is an exclusive fea-ture found only in Kurz-Kasch Aristocrat dials.Kurz-Kasch dials "Align Rite"-"Hold Tite.'

The worldoverKurz-KaschAristocratE -Z Toonis recog-nized asthe real"Key toSimplifiedTuning"

KURZ-KASCH ARISTOCRAT E -Z TOONGives that close tuning so necessary, with sta-tions numerous and close together. Simple to in-stall, remove your present dial and slip on anE -Z Toon. Kurz-Kasch workmanship and qualitybrings in stations you never heard before. Fam-ous Kurz-Kasch split bushing method of mount-ing. You'll never realize how simple it is to tuneyour set until you use Kurz-Kasch AristocratE -Z Toon.

KURZ-KASCHcAristocratE-z-119,9NGROUP CONTROL

For the Set

You Have!

Tunes two or more units by means of one MasterControl and at the same time provides vernier

adjustment for eachseparate unit. Allthe advantages ofsingle control, with

none of the dis-advantages.

et you....-Fey the :et youthyou

$7.50LIST

Complete

For the Set

You Build!

Simple to install, comes complete, nothing elseto buy. No panel to drill, complete instructionswith each kit. Nothing to get out of order.Simplifies tuning without loss of efficiency. Anydealer can supply. Write for illustrated folder.

Manufactured by

THE KURZ-KASCH COMPANYLargest exclusive Moulders of Bakelite

FACTORY and OFFICE: DAYTON, OHIO

20 RADIO WORLD March 6, 1926

Diamond Deluged with PraiseRESULTS EDITOR:

I have built the Diamond of the Air. Ihave heard over 60 distant stations. Thevolume on all these setations is terrfic. Asfor tone quality, it is the best I have everheard. Some of the stations I have re-ceived are: CNRO, KFL, KOA, WMBF,etc. The selectivity of this set is superb.

ROBERT J. BERLUND,1520 16th Ave.,

Rockford, Ill.* *

RESULTS EDITOR:I have built the Diamond of the Air

USED IN THEDIAMOND OF THE AIR

CIRCUIT

Connectionscupped and

spread apart

75r Cass' Solderingill

I

/yr Sy BROOKLYN MITAL INSTAMPG CORP718 ArLantic Ave. Brooklyn, 71.Y_I

U. S. Patent No. 1,50,311/1

using PA -volt tubes, and am obtaininggreat distance with loudspeaker volume.During the recent international Tests Ireceived stations in Mexico City andHavana.

EUGENE UNSWORTH,1413 Louisiana Ave.,

New Orleans, La.* * *

RESULTS EDITOR:I have written before, expressing the

great results which I obtained with my1926 Model Diamond of the Air, but re-cently I pulled a stunt which I think isworthy of special mention. KFI, KGO,KOA and CZE (Mexico City), were tunedin while all the local stations were goingfull blast. The wavelength difference be-tween WCAP and KFI is PA meters.I could separate them perfectly withoutany trouble. WSAI was also tearing upthe ether when I tuned in KOA. WDAF

was sightseeing around Kansas Citywhen KGO was tuned in. CZE, MexicoCity bothers me when KGO is on the air.Hal Hal Boy, this is some set

G. IL THOMAS,Care The Peoples Bank of

Hartsville,Hartsville, S. C.r

RESULTS EDITOR:Have built the Diamond of the Mr,

with parts that I bought from the EnterCity Radio Store of 223 Fulton Street, N.Y. City. I find the above set the bestset for volume and selectivity that I haveever built. To day I have logged 46 longdistance stations while locals were on, onthe speaker. I can recommend this setto anyone.

DAVID WHITE.,514 West 177th St.,

N. Y. City.

Use a Loose BandOn Your Earphones

If the band on a pair of earphones isvery tight it should be loosened up bybending it outward, as the tight spring-iness exerts too much pressure on thehead. One radioist, who in his youngerdays was an ardent amateur, habituallyused earphones that clung too tightly tohim, and as a result he has less hair onthat semi -circumference where the phone

band rested than he has on the rest ofhis head. He wears this blemish as abadge of honor and devotion to his hobby.Most of us would rather forego the honor,so let's do it

Mg DIAMOND OP THE AIR BOOKLET.containing complete constructional data and dingrams, with blue print, SOc. Columbia Print,145 W. 45th St. N. Y. C.

v07 TUBES Will Give You Greater Satisfaction If YouAre Using Resistance Coupled Amplification for Your Receiver

TRY VEBY DRY CELL Power Tubes (Type DXP)Hi -Mu Tubes (Type DXA)

Increased volume without distortion and lower plate voltage are some ofthe advantages obtained by using VEBY AF20 Tubes for resistance coupledamplification. They are especially designed for this purpose and have anamplification factor of 20 as compared to 7 or 8 of ordinary tubes.

VEBY POWER TUBEWhile designed for use in the last

stage of a resistance coupled amplifier,the VEBY AF6 Power Tube is guaran-teed to give more volume and eliminate

distortion on any receiver, regardless of type of am-plification used.

VEBY-VEBY-

AF 20 Amplifier TubeDXA Dry Cell Tube

(FOR RESISTANCE COUPLING)AF 6 Power Tube, $4.50DXP Dry Cell Power Tube, $3.00

$3.00

VEBY RADIO COMPANY47-51 MORRIS AVENUE NEWARK, N. J.

VEBY Resistor No. 100VEBY RESISTORS ARE

SPECIFIED BY

HERMAN BERNARDFOR USE ON THE

"DIAMOND OFTHE AIR"

Manufactured in a Complete Rangeof Values From 2,500 Ohms to 10

Megohms.

Veby 3 -stage resistance -coupledamplifier, $10.00

Equipped with new UX socketarrangement.

March 6, 1926 RADIO WORLD 27

Electrical Toaster Used as Aerial

DAVID B. KOPP, of Boston, is shown using an ordinary breadtoaster as an aerialfor a crystal set. Local stations come in with great clarity, while using the toaster

aerial. (Underwood & Underwood).

Writing by Radio

THE "RADIO PEN," one of the latest wonders in radio development, is anotherof the inventions of C. Francis Jenkins of Washington, D. C. No human handsare required to operate this pen. It is actuated by radio waves sent out from abroadcasting station. In a recent demonstration, it was operated by radio waves

from a transmitting station four miles away. (Harris & Ewing).

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.

Good Back Numbers of

RP_DIO WORLDTL. following inuatested articles bays eP-peared la moat Wu. ai RADIO WORLD,1925:July 4-The 111146.311 Prtable. by Herbert

Hayden. The Freedom itefles. by Caps T. V.O'Rourke.

July 1 1 --Xlm Baby "super," by J. R. AndersonA I . Dia I Pormole 11.41Iet. 4 Capt P. V.O'Rourke.

July I b-A111114,00.11 4 . Tube Bum- HeterodyneThe I -Tube 54.reonl Howler.by Pere, War -

Arem. A Good Battery Connect., by HerbertO. Hayden.

Aug. I -Enormous Velum. en DX Static... bySidney IL Fink el. teirs The kletropall tenLocal Set. by J. E. Anderson

Aug. (I-The lbolutica R4041, ty Caps. P.O'Rourke.O'Rourke. The Midget-A 1 -Tube Set inSewing Machine Cabinet. by Herbert R Hay-den How le Build Your Tlnl Set. byHerman Bernard.

Aug. 15--Capt. P. V. O'Rourke. Favorite AudioAmplifier. Set Thai Tame ingenuity. byLewis Winner. The Loop Jack in Tb. Dia-mond, by Herman Bernard.

Aug. 22-The 5 -Tube Diamond. byTtnkleutb. A Home -Made Toroidal Col 4George It. Hostetler Crystal Sete That YouCan leg. by Herman Bernard.

Sept. Ills Model Diamond of the Al,.(Part 11. by Herman Bernard. A 25-10-110Meter Receiver. by filidney a TInkel stein.

Sept. I 11-Dtantond of the Air (Part 21. Dy Bor-man Harmed. A 1 -Dial. 1 -Tube Speaker fleeby Pony Warren. A Tube B Battery gam -Water. by Lewis Winner.

Sept. 213-Tbe 8 -Tube Soper- Heterodyne. by Sid -my IL Finkelstein. Diamond of the Al. ( PartI). by Herm., Bernard. The 5 -Tube Brown-

- Dr ake. by Capt. P V. O'Rourke.Oat. 3-The Thordarson -Wade Bet (Part 11, byHerman Bement Mod Grid Leak. byHerbert W Hayden. Trouble Bbooting forDiamond 6f the AU.Ott. 10-The 3 -Tube, 3-Cies-nit Tuner, by Capt.P. V. CP' Enurke. The DX Set That Thrilled

Jack. by Lewis Winner. The TherdareemWad* Set (P.O 31. by Herman Bernard.0.t. 17 --The 'Thoroughbred -Tube DX Set).by Herbert Hayden. O'llourke's Favorite SW

Flee by Cept. Peter V. O'Rourke. Thertordarson- Wade Bet (Part S) . by HermanBernard. Trouble Shooting Article.Oct. 24-A Phonograph Cabinet Set. by LewisWinner. The Thoroughbred. by Herbert Har-

den (Part 2i.

Nev. 7-.L I -Tube Dry -all Mead, by 0.04.P. V. O'Rourke. One of the Bast CrystalBets, by Herbert E. Hand... I - TOW DXSet. Herman Bernard. The 4 -Tube RobertReceiver, by Neal Fitralart

NW. 14-The 4 -Tube DX Special. by Herbert MHayden_ The Set That Water Leudened.apt. P. V. O'Rourke. A Rewire, for /du tieLeven. by Lewis %Inner.

No, 2 I - DX Super - Eleterodysm, by J. ILAnderson. A Resistenre Controlled Set. byPerry Werren. A /-Tube A - Race iv gr. byHerbert E. Hayden.

Nes. 25 --The Zero Potential loop, by TrackFreer. The 1 -Tube Heeded flecelver. by Jnctergen.5- Torah/ HP Re, one Crtatal. by

Lewitt Winner. The Diamond of the Alt(in Telt and D !scram ) , by Herman Bernard.D ee. I 2 -A Self -Contained Hotelier. by II I.

Hayden (Part IL B Battery Migainater. b7Lewis Winner (Holiday Gine Ns ) .

Dee. I 0-Tbe Lemma Entertainer. by RdBpieslet. Feldman 5 -Tube Bet. by Cowie W.Feldman

Doe. 25-Tott Regenerative Wave Trap. by JohnF Rider. The 5 -Tubs Tune. HT Bet. b)Capt. P. V. O'Rourke.

11126:

is.. 2-The 1-0 Bet for Simplicity. by CaptP. V. O'Rourke.

Jac 2-71.te 4 -Tube DX Symphony Bet. by A.Irving Wits. Skillfully Made 1 -Dial Set,by Herman Bernard.

J.U. 16.-Andereon'e 5 -Tube Quality Receiver.The Raytheon B. Eliminator, by Lewis Win.

late. 23-11ce 4 -Tube Diamond of the At,. byHerman Bernard. The Antemmtrol, by Her-bert E. Hayden (Part 11. B Batteries LettSix Months. by B. E. FInkelgteln.

Jag. 90-An Individual Al' Amplifier. by H. E.Hayden The A Men/afro'. by Herbert Hay-den )Par 21. TraPPIng Out Super PowerIn New Jens)), by Cap, P. V. O'Rourke.

Feb. 13-The Funny ( 4 at 9 tubes), by Leo Tea-m) (Pert 11 The Great 1 -Tube DX Bet.by Herman Bernard.

Feb. 13-Anderson'. 5 -Tube Economical Receiver.Trouble -Shooting for Novices, by SL BStroek. Th. Fenwy, by Leo Fenvt1Part 21.

Feb. 251-The 8 -Tub V IttOteeri. by Herbert S.Hayden. The Fume, by Leo Fennel(Pert 31. (IL.110' Sunned In 3 -Tube Set.by Brainard Foote.

Feb. 27-The 4 -tube DX Dandy, by HobertHayden. Umbrella Aerial for DX, by 11.40Gernebeck. Part I of The Victoreen.

Any too,. 134. Amy 7 MOH. 80.00. Allthew 31 goblet for $4.90. ar dart subscript lee withany Imo. RADIO WORLD. 145 W. 45tb St.,N. Y. C.

28 RADIO WORLD March 6, 1926

Labor Will Erect OwnStation In Australia

WASHINGTON.Organized labor is going to try its hand

at broadcasting in Australia, according toa report to the Department of Commerce.The new station, with a call of 2KY, willbe of superpower. The Trades Hallauthorities are reported as expecting toovercome any causing of interference.

FOR CLEAR, QUIET "Be POWER

12 Calls41,foiLa Lasts Indefinitely-Pays for Itself

R,coponii and performance unheard of before. Remnant.] a, negli-Zp":07.1...1,'1,4,1:7--g=r77=11Vt''..itAtZd, irtN:IM.,1;r.. In

Po Radio Laboratories. Po, Sri. Ise[. Standards Radio Newsc.. and oilier Important lastilutioas. ganialsedSolid Riaib4i Co., an Insurance NmIns add and I.p.. Eat obe. Owl... Hem, ragged aisles. Order yourelodI

SEND NO MONEY i=tra:reiTi'ag,Entrant.: I batteries in series ,96 610a.p) PN

tw.,:a.derort:, il exavilLF balerlas. 6 per cent discount or ma

WORLD BATTERY COMPANY121 Wabash Ave., Dept. 82 Chicago.of tiLt Famous World Radio .4. MoranPylon alvolL 100 App. 811.2.5: Ira Amy. 1404iiittrZ0.09.sgainasd with Solid &ibler Coo,

RADIOStorage "B" Battery

WorldTORAGE BATTERIES

See roar Radio Dials at 210meters ti.a. the 000

tWOOt'* o

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tNTrfr'sots'sn'e*.

GEM TUBEA Guaranteed Radio Tuba

Within Reach of Allwrory lobe guanotood. A tubefor a dollar of if value.trial order will novince you esit ion thetuaind of CharsBend your orders at one.Orders sent C.O.D. Per01 Pon.Typo 1954Typo.. 199 $10°TYPO 20IA

larith staiedwd Halo) EACHDealers. Write for Diwouate.

GEM TUBE CO.Dept. W.. 200 B'ray. N. Y. O.220 So. State St.. Chicago.Lafayette Bldg.. Detroit. Niel -

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

RESULTSReaders report on their ex-

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

RESULTS EDITOR:I built the 3 -Tube 3 -Circuit receiver de-

scribed by Capt. P. V. O'Rourke in theOct. 10 issue of RADIO WORLD and receivedmarvelous results as to distance and volume.

JOSEPH S. GORAL,Rt. 2, Bx. 35,

Latrobe, Pa.*

RESULTS EDITOR:I built the Diamond of the Air and am

getting very good results. I have re-ceived stations from all over the countrywith loudspeaker volume and with won-derful quality. GEORGE FILKAS,

4456 N. 17th St., Philadelphia, Pa.

get/926 AnirrrrffidIllasinstea calatay I

Which ntain all latestStandard Radio Merchandise

co

AT SLASHED PRICES! IAnd Up -to -Date Log Book

IT WILL PAY YOU TO BUY FROM US. WeParry one of the largest lines el Rana in the Ent.

Don't miss the wonderful opportunityto participate in this Great Sale.

Rush your request at one.To cover the cost of palling enclose 101.

ECONOMY RADIO SALES COMPANY288 6th Ave. Dept E New York

DEAL DIRECT AND SAVE REAL MONEY

ZILTR7-bOli3L055CONDENSER

SPECIAL CUTLASS PLAT Ey, OIST.Itl UTE TairiaLIONS EVENLY OVER Tor DIAL Sit PL,rIESTUNING CAPACITY 0005 MOO

$8.00PHENIX RADIO CORP., 116-F E.' 25 St., N.Y. C.

TWO -FOR -ONE SUBSCRIPTION OFFERRadio World has made arrangements-To offer a year's aubaoiption FREE for any one of the following publicationsyear's suk.scriptioe for RADIO WORLD,-POPULAR RADIO or-RADIO BROADCAST or-SCIENCE AND INVENTION ce

-RADIO NEWS-RADIO DEALER or

-RADIO JOURNAL or-RADIO (San Franclaco) or-RADIO ALE-COLLIER'S-BOYS' LIFE

This is the way to get two publications-for the price el coot-Send Hee today for RADIO WORLD-for two year (regular pries-Ica S2 numbers)-and select any one of the other-nine publications for twelve month.

-Add Mel yen, eats lot-Canadian or Foreign Pottage-Present RADIO WORLD subscribers-can take advantage of dila offer by-extending bubscriptions one year-41 they send renewals NOW.

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RADIO WORLD'S Special Two-ForPriee-of.One SUBSCRIPTION BLANKRADIO WORLD. 14S West 45th St... N. Y. ChetEnclosed find WOO, for which send me RADIO WORLD for twelve month (52 numbers), 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), Boy a' Life, or Radio Journal, Collier's or Radio Age (or $10.00 for two yearlysubscriptions).

Indicate if renewalOffer Good UntilMarch 24.

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City and State

FENWAY BLUE PRINTSACTUAL SIZE LAYOUTS

"PICTURE.' DRAWINGS. COIL DATAEVERYTHING YOU SHOULD KNOW

Poke. Penni 5.00Yea Caa:1 G Wrong alth FOSYMY DIPOPYISTO,

LEO FEN WAY29 WEST 64th STREET NEW YORK. N. Y.

11 HARI) RUBBEI-1-11-SHEET-ROD-TUBING

In various SlursSODOM Hata Rubber Parts Made t Maw

Send Sample or Sketch fw Cluotatisa

PANELS ANY SIZERADION AND HARD RUBBER

PRICE LIST FOR ALL RADION PRODUCTSMAILED ON REQUEST

WHOLESALE RETAILNEW YORK HARD RUBBER TURNING

COMPANY212 CENTRE STREET NEW YORK

PARTSSM Low Loss Inductances

All-bakelite Low LossInterchangeable Coils for50.550 meters, Thesenew coils may be usedas oscillators, antenna

adapters and RF trans-formers in standardcircuits.Price of all types,

Each $2.50

Sockets for any MaeCoils. Each Lin

SM Type 316 Con-densers are fur-nished, all brassplates, d i e castframe and doubleadjustable conebearings. May beganged by placingone socket behindanother, the shaftsinterlocking in anydesired relation.SLF .00035 mfd.capacity for alltypes of SM In.terchaniteablecoils. Price .. $5.75

SM Vernier DialsThe SM Type 801Vernier Dials are ofall Bakelite con-struction. Zero to100 - clockwise -counter -clockwise or360 degrees (forRemler Condensers)in a single type. Inppearanceand operation theSM is the finestvernier dial on themarket, Price,each MSS

SM 210 and 211 TransformersDesigned so thatmaximum ampli-fication will beobtained at 60Kilocycles.Availablein matched setsof any number.No. 210 is iron -core type whileNo. 211 is of theair -core typesupplied withmeasured tuningcondenser. Each transformer is furnishedwith individual laboratory curve chart.Price: both Types .58.10 each

Sr, there and other SM Ports at yourDealer, or write Tar nrrwlar

Silver -Marshall, Inc.110-R South Wabash A

CHICAGO, ILLINOIS

March 6, 1926 RADIO WORLD 29

LOUD SPEAKER RECEPTIONfrom either coast on three tubes

Blueprint and instructions $1.00Necessary low loss coil 52.50Beautiful finished instrument $35.00

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

VICTOREENSuper Heterodyne

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

No Matching of Tubes

Range -Clarity -Selectivity-,

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

Orders shipped same day as received.

4.00

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

411111W11111111

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111101111.

THE VICTOREEN (from page 12)fier. The red A plus lead is soldered tothe F plus socket post of the third tubefrom the left. The green B plus detectorlead is connected to the plus post of thefirst audio -transformer.

As to C minus, A minus and B minus,the constructor must choose between lo-cating the C battery on a level with theset, or below with the other batteries.

If the decision is to place it below, thebetter plan is to use the black cable forA minus, B minus being connected to Aminus by a separate lead, not a part ofthe cable, right at the batteries. Thisenables you to use the yellow cable leadfor C minus, soldering it to the lug on theF post of the first audio transformer, andsnipping off the excess bus bar lead. Cplus would be joined to both A minus andB minus at the batteries.

The other scheme, with the C battery ona level with the set, would enable you tomake the yellow lead B minus and theblack one A minus, carrying these downto the batteries along with the other cableleads, while two flexible leads would beused for the C battery. One of thesewould be soldered to the common jointof A minus and B minus, the first wire weinstalled, while the other would run frontthe F posts of the two audio transform-ers and would be C minus.

Connect antenna and ground to theposts of the antenna coupler so marked,or plug in a loop at the loop jack. Con-nect the speaker to the final jack, J3,lower right (now that you are facing thepanel) and turn on the switch.

Condenser C4, the .006 mfd. safetydevice, was not included in the wiringdirections, as it is not in the list of parts.To include it, simply interrupt the leadfrom the plate of the oscillator tube onits way to the stator plates, of C2, andplace the condenser C4 in between, one

side of C4 tube to the plate, the other sideof C4 to the stator plates of a.

C8 has not been included in the wiringdirections. It is not necessary, but maybe included, if desired, being about 1.0mfd. C5 and C8 are interchangeable, andas CS was considered in the wiring direc-tions, C8 was omitted.

FREE NTLAMIF YOUR INVENTION Is new and useful It la

patentable. Seed me your UMW,.2. H. POLACHEK, 70 Wall St., Now Yeti

Reg. Patent AtterneyEnghwer

DON'T TRY TO TUNE BY GUESSKNOW where to place your dials Ice eachstation in America.KNOW what station you receive withoutwaiting announcement.

You eon do both with RADEXCoin orSend 25c stamp.

RADEX, Box 143-M, Cleveland, 0.

Vacuum TubesRebuilt

$1.00 eachPOS1TITIOLT GUARAN-

TKRD equal to new tubes Inevery respect. Money will berefunded If tubes prone un-satisfactory for RSV reasonother than burn -outs.

Bend us your broken andburned out tubes by parcelpost. (Not necessary to in-sure or guard against break-age.) We make return s1111, -men. by Prebt post C.O.O.and try to maintain 24 -hourserrIce.

HARVARD RADIOLABORATORIESMI Old Colony Avenue

South Boston. Mass.

Verified Receptionfrom Paris by Cadiz,Ohio, Radio Fan

Coast to Coast on a Loopis easy with a

Victoreen " Super "

No. 170 R. F. Transformer

The Heart of the Circuit4-No. 170 R. F. TRANSFORMERS

at $7.00 each and1-No. 150 Coupling Unit at $5.50No oscillations, howls or squeals-nomatching of tubes.Complete parts to build the "Victoreen"can be purchased of your dealers atmoderate cost.Ask your dealer for free "Victoreen" folderwhich contains hook-up and complete in-formation, or write us direct.

THE GEORGE W. WALKER CO.6515 CARNEGIE AVE. CLEVELAND, OHIO

Branch Offices in Principal Cities

30 RADIO WORLD March 6, 1926

TRADIOGRAMSWesley S. Scharp, well-known to the

radio fraternity, has become a partner inthe firm of Stoner & Heath, manufac-turers' agents of 122 Greenwich Street,New York City. They are sole agents inthis territory for the Centralab productswhich are occupying front rank. Theyalso represent Bodine Mfg. Co., Globe

RIGHT TO THE POINT!flireme accuracy of dial reading is assuredwhen you use EUREKA DIALPOINTERS! Tuning In distance lesimplified

Polished Nickel or Gilt, % or %" 1 OC. W. BUTTS, ha.

40 Haden Place tart Orange, N. J.Dealer Inquiries

Snlicitea.

Gets Everything but Noise!Amazing new Aerial guaranteed to elnate all power

nolo. tsurh as leaky transformers. generators, motor gun,c , Planta, etc. Cuts static, regeneradon howls and squeals2. Dr. G[ bets. Oakland. Cal , gays improves repeal:ton 60 %.

dundreds other testirrauntals. Wonderful results. Mr. Floec.k,Grand Haven. Mich heard foreign station. during teats withKane Antennae. Easy _$ 1 ww Irina° BLUE PRINT -rosins irgs;dpr -.1_ or dou:rT)IfIl:rtetecr Vinrieti opuntlty. Send TODnAt..KANEPNVENNAE CO. Dept. rag, 3343 W. Monroe Chicago

E -F -F -I -C -I -E -N -C -YUntil you own a Roberts "B" Batteryyou will not know what real radio joyyou are missing. It is efficient, recharge-able and indestructible. You can't wearit out.

Price list as before.ROBERTS BATTERY COMPANYItzt Myrtle Avenue Brooklyn, N. Y.

FREERADIO

CATALOGWRITE for a copy, of

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

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CHICAGO SALVAGESTOCK STORES501 S. State Street, CHICAGO, U. S. A.

S. HAMMER RADIO CO.303 Atkins Avenue, Brooklyn, N. Y.

Please arid me FREE, Your NEWRADIO CATALOG

NameAddressCity State

FILL OUT AND MAIL

Electr'-t Co., Mack Moulded Products andnew Perlesz foundation unit and

nave just added Cell -O -Meter, a newmeter which accurately tells the conditionof the storage batery.

The Carter flat plug is an original andefficient plug providing quick and positivemeans for inserting and removing phonecords without the aid of any other de-vices. Secure anchorage results, and theplug is highly ornamental, the shape ofthe handle conforming with that of thedials on the panel. The Carter dialiteprovides illumination for the front of thepanel and at the same time can be usedas a combination filament switch. The newCarter 14 -inch loop which is highly effi-cient is also ready. These and the fullline of Carter products are handled inNew York by the genial P. W. Mack at1270 Broadway. The well -liked Acmeline also handled by Mr. Mack is goingstrong, orders for the new Acme ConeSpeaker coming in faster than they canbe filled.

The Ekko Company, 111 W. MonroeSt., Chicago, Ill., are putting out a groundclamp also a line of connectives uniquefor their very simplicity. These con-nectives are made for Edison phonograph,Columbia, Pathe, Brunswick, etc.

The Lawn Battery Works, 1545 VanBuren St., Chicago, Ill., have designed acabinet enclosing a 96 -volt Lawn B Bat-tery and Lawn Rectifier with switch on

lie APSOCKET

" It getsthatlast

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Mechanically .1t5 Perfect.AiRop PRODUCTS Co. Mfr188 N.J. R Rd. Ave Newark,N.J.

inside of cabinet cover, which allows in-stant use of battery for receiving orcharging by simply throwing switch. Fullinformation on this will be sent by justmentioning RADIO WORLD.

This should prove interesting to thereal radio fan.

is.i.u8lnAls0 knurl) en"Describes fully the complete Crosley line of radiofrequency seta, regenerative sets (licensed underArmstrong U. B. Potent No. 1,113.149) and parts.

THE CROSLEY RADIO CORPORATIONCInsinnII Delo

Radio's biggest season is here. Get ournew catalog showing huge sacks ofradio parts, sets, kits, at lowest rock -bottom prices. Quick service,wonderful special offer on bestsets, tubes, batteries. Writefor free copy.W. C. Braun Co. 32-60 So. Clinton St.. Chicago, U. 8. A.

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45 volts, 15.15; 90 volts. $10.00; 112% rata,118.50; 185 volts. $14.75; 157% volts. 314.80.Testy. the biggest buy today. Basta <harass on loscurrent. Including 82.volt mama. Any sweat de-tector plate voltage had. 'Ported and aPPreved bfleadhig uthoritles such as Popular Radio Labor -&torte.. Over 8 years sold on a non -red tope. 80 -daytrial offer with complete refund if om thermal*,satisfied. Further guaranteed 3 year. Smock -downkits at great savings. Complete "klassler. "5" bat-tery charger, 12.75. Sample cell, 35. Order direct-send no money-simply Psi the ernressaiss teston delivery. Or write for toy free literature. testymonials and parent... Same day shipments. 11.

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QUICK -ACTION CLASSIFIED ADS.10 Cents a Word. 10 Words Minimum. Cash with Order.

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

SETS REBUILT into Diamond or Hammarlund.Prospect Laboratories, 912 President St.. Brook-lyn, N. Y.

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EXPERIENCED RADIO MAN WANTS posi-tion. Manford Flowers, Clovis, New Mexico.

HELP WANTED MALEEARN 3110 to $250 monthly, expenses paid as

Railway Traffic Inspector. We secure positionfor you after complethin of 3 months' home studycourse or money refunded. Excellent opportuni-ties. Write for Free Booklet, G-161 Stand. Busi-ness Training Inst.. Buffalo, N. Y.

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RADIO WORLDRADIO WORLD

Please send me RADIO WORLD forplease find enclosed $SUBSCRIPTION RATES:Single Copy $ .15Three Months 1.50Six Months 3.00One Year, 52 Issues 6.00Add $1.00 a Year for ForeignPostage; 50c for Canadian Posaage.

145 West 45th Street, New York City(last East of Broadway)

months, for which

March 6, 1926 RADIO WORLD

October Exports SetRecord at $1,317,846

Washington.-Radio exports for October, 1925, reached a new high total o$1,317,846, according to figures releasedby the bureau of Foreign and DomesticCommerce. The principal purchasers of

BEAUTY -QUALITY -LOW PRICETYPE 5SS $455 -Tube Tuned Radio Frequeney.TYPE itRR6.Tube ResIstanee Coupled Audis bead $50Radio FrequencyIf your dealer cannot make immediatedelivery we will chip direct from factoryAmericap Interstate Radio Service

103 Granwich Street. New York CityDistributors, Jobbers, Dealers, write for special trade terms.

HARD RUBBER PANELSSize. Black

7 a 10 .327 a 12 JO7 so 14 .427 a 18 .,sa7 a 21 .647 a 24 .757 x 26 .857 x 30 4s

RIX RADIOSUPPLY HOUSE, Inc.

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

LISTEN TO YOUR LOCAL STATIONSwith

THE TALKING BOOKReg. U. S. Pat. Off.

A complete radio set in the form of a book, boundIn One cloth with gold Bt110D1.11. EquIPPed withTowers head phones and antenna.

Guaranteed range fifteen miles.An Ideal auxiliary to a tubs set. Costs nothing

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

traveling man.PRICE FIVE DOLLARS. sent prepaid.Approved by the Popular Radio Laboratory

Mfd. byLISTEN -1N PUBLISHING CO.

110 Main St. Cambridge, Maas.Publishers of the Listen -In Radio Record.

If you live within ten miles of a broadcastingstation write for exclusive egency.

American radio equipment during Octo-ber were Canada, $808,943; Japan, $151,-247; Australia, $87,849; United Kingdom,$71,577; Mexico, $66,118.

New Tube ReviverWorks Off the Main

The International Resistance Co., ofPhiladelphia, Pa., is putting out a cleverdevice, for reviving and restoring to itsoriginal efficiency every tube employinga thorium treated filament, where thefilament is not actually burned out. Itis designed to operate from any 110 or120 volt line, AC or DC. All that is nec-essary to restore the tube is to screw thedevice into the electric socket, press thebutton for 45 seconds and then allow itto stay in the socket for 10 minutes. Thisdevice is known as "The Socket Tube Re-viver." Any dissipation of heat, plus areasonable amount of overload, is welltaken care of. These revivers are madefor the 201A and the 199 type tubes.

Tested and Approved by RADIO WORLDLaboratories).

LITERATUREJ. H. Fowler. Morstein, Pa. (Dealer).I.. A. Sande, R.F.D. 2, Box 31. Valley City,

N. D.Hagen, and Hageman Radio Co., Teaneck. N.

J. (Dealer).Edward Tlatt, R.F.D. I. Medina. N. Y.G. W. Yeago, Box 205, Holliday Cove. W. Va.

(Dealer).Cecil Taylor. Plano, Tex.John B. Foster, R. 1, Box 59. Meelyville, Mo.Tony Cheerman, Box 247, Homer City, Pa.Louis M. Blum, 226 East Long St. Columbus.

Ohio.J. Tibbits, 15803 Mettal Ave., Detroit. Mich.

W. Horan, 306 E. 70th St., N. Y. City.ranklin P. White. 1519 West Colorado Ave..

Colorado Springs, ColaRoy C. Aders, 1014 South Prince St., Princeton,

Ind.S. E. Mognet, Leechburg. Pa. (Dealer).Frank Erwin, 73 W. 49th St., Bayonne, N. J.Rudolph Nilsen, 1033 57th St., Brooklyn. N. Y.

(Dealer).F. W. Kona, 2112 Waveland Ave., Chicago, DLFred Meyers, 20 Montana Ave., Buffalo, N. Y.

(Dealer).Bert Kendrick, Providence. Utah. (Dealer).William A. Geddes, 15 Climatis St., Providence.

R. L (Dealer).P. G. Docksey, 3 Rosewood Ave.. London,

Ontario, Canada.

NAME CHANGESRadio Underwriting and Brokerage Corp., N.

Y. City, to A. B. Morely & Co.

The Miracle Ti )HFE

How This 1q,

Magic Dial !Precision Instrument Contributes to the Ease and

Comfort of Modern Life

Many sets - home -con-structed or factory-built-render excellent service, ex.cept tuning in low wave-length stations is an ordeal,they are so frightfullycrowded on the dials. Thisis due to the semi -circularplates of the tuning con-densers. Why rip your setapart to put in other con-densers when all you needdo is slip on "Bruno" MagicDials, without so much asputting a screw or bolt onthe panel?

Uncrowds the air by gener-ously separating law wave-length stations, making anycondenser that is not straight-line frequency tune as if itwere! It takes all the troubleout of tuning I The MagicDial is genuine mouldedBakelite and represents themost important radio con.tribution so far this year....

$2.50

The Magic DialFor straight-line frequency condensers use the "BRUNO" SLO MOSHEN VERNIERDIAL (same face as the Magic Dial) 52.00

POWERTONE CONE SPEAKER18" Diaphragm. 5 -Day, Money -

Back, Guarantee. Charming Tons.$14A9

Powertone Electric Co223 Fulton Street

NewYork City

Complete Kit for5 -Tube, 1 -DialPOWERTONE $22.50Build this set and enjoy acoustical synchronizing-real tone quality. SLF condenser and BrunoSto-Mashes, Vernier dial. Blueprint FREE witheach kit.

NEW CORPORATIONSMetro Electric and Radio Shop, Ridgewood, L.

Is., N. Y., $3,000; F. J. and E. Keinath, W. Dual.(Atty., L. C. Ringe).

Ben Radio Corp., Freeport, N. Y., $50,000; C.H. Nichols. S. Edwards. (Atty., W. P. Bockats.Freeport, N. Y.)

Schneider Horney Radio Research Laboratories,experiments. N. Y. City, 200 common. no par;

CAPITAL INCREASESGiant Radio Battery Co.. N. Y. City. 510,003 to

$50.000.

$1.50 FOR YOUR OLDRADIO TUBES

regardless make or condition, toward pur-chase of each new standard $2.50 tube.Positively guaranteed. We do not sell re-built or bootleg tubes. Agents wanted.SUPER -SERVICE LABORATORIES, Dept.59, Room 58, 39 West Adams, Chicago, Ill.

VEBY HIGH -MU TUBESMade ea pecially for Reelstenee Coupled Amplifies,.Now you can net more volume with greater clarity.A. F. 20 for the 1st and 2nd Stage $3.00A. F. 8 Pourer Tube for the 3rd Stage 4.50

VEBY RADIO CO.47-51 Morris Avenue Newark. N. 1.

414q a>rllt

FRES"

SIASTERPECNAT AUTHORIZED

FRESHMAN DEALERS ONLY

The-Daven Super -Amplifierfor volume and tone quality

3 STAGES RESISTANCE COUPLEDECONOMICAL DISTORTIONLESS

Easily added to any setSaves Several Hour.' AssemblyFo Sale by All Good Dealers

Tonic forsick tubes

fromanylamp

socket.A.C. or

D.C.,110 volts

$4.50and thiscoupon

for201-A

and199

types

°OWL'Tube Reviver

Renew all of your tube. for leethan the con of two. Send nomoney. Reviver will be mailedC. 0. D. to those sending coupon.Satisfaction. or money beck.

BRINGS QUICK RELIEFInternational Resistance Co.,Perry Bldg., Philadelphia.

Please send me by prepaid ParcelPest. C. O. D.. one SOCKET TubeRAVITAR, type ea noted. I will ParPalmas 4.50-with the tmderstand-ins that money will be returned if Iam not mtlzely Batt/111mlName

Address

City State

Cress noteel

201.A196

RADIO WORLD March 6, 1926

SPECIALISTS WHO CATER TO VICTOREEN BUILDERS

Including the Same Parts as Described inThis Issue of Radio World

We have sold more than 300 of these 8 -tube Kits all over thecountry to enthusiastic owners who write us most glowingly ofresults. A wizard for Distance, Selectivity, Volume. Tune out anylocal station and get real DX on two -or -three meter wave differ-ence. One of the few super -heterodynes with air -core trans-formers. No self -oscillations, whistles or squeals. Easier tuningbecause air -core transformers operate at higher frequencies. Ademonstration will convince you. Tubes, batteries and aerial, ofcourse, not included. Packed, ready for you anywhere.

LIST OF THE PARTS INCLUDED IN THISVICTOREEN SUPER -HETERODYNE

Four Victoreen RF Transformers, No. 170One Victoreen Antenna Coupler, No. 160One Victoreen Oscillator Coil, No. 150Eight Kurz-Kasch Standard Bakelite SocketsTwo .0005 mfd. Hammarlund SLF CondensersTwo Kurz-Kasch E-Z-Toon Vernier DialsTwo .00025 mfd. Grid Condensers with MountingsTwo 2-megohm Grid LeaksOne .001 mfd. Fixed CondenserOne 1.0 mfd. By -Pass CondenserOne 400 ohm Victoreen PotentiometerTwo Victoreen 30 ohm RheostatsTwo MeloformersOne 7".e24" Drilled and Engraved PanelOne 133/a"523" BaseboardTwo No. 104 Carter Double -Circuit JacksOne No. 103 Carter Single Automatic FilamentControl JackOne Imp Battery SwitchSeven Binding PostsTwo 6 ohm Victoreen Rheostats

We Specialize in Complete KitsDESCRIBED IN THIS OR ANY

OTHER RADIO MAGAZINE...*\Hammarlund-Roberts, Silver -Marshall, Bremer -Tully, Harkness, Etc.(

Only OneKind ofQuality

-the BestWe

JIVRTING GOODS CO.512 MARKET ST., PHILA. PA.

30 Years'Experience

Back ofEach Sale

VICTOREEN SUPER!Coast to Coast on a. Loop! Verified Reception from Paris by Cadiz, Ohio, Radio Fan on aVictoreen. Built with "Tuned" R. F. Transformers of Air Core Construction. No Oscillations,Howls or Squeals-No Matching of Tubes. Range-Clarity-Volume-.Selectivity-Ease

of Operation.COMPLETE KIT, $54.95CONSISTING OF THE FOLLOWING LIST OF HIGH -C1 ASS PARTS:1 Victoreen Antenna Coupler No. 160. 2 6 Ohm DeJur Rheostats.4 Victoreen R. F. Transformers No. 170. 2 Precise Audio Transformers.1 Victoreen Oscillator Coil No. 150.

1 7"x24" Drilled and Engraved Panel.8 Bell Bakelite Standard Sockets.1 8%"x23" Baseboard.2 .0005 Mfd. Montrose SLF Condensers.2 Double Circuit Jacks.2 Apex Vernier Dials.

a 00025 Mfd. Grid Condensers with Mountings 1 Single Automatic Filament Control Jack.2 2-Megohro Grid Leaks 1 Filament Switch.1 .001 Mfd. Fixed Condenser. 7 Binding Posts.1 1.01 Mfd. Tohe By -Pass Condenser. 1 Binding Post Strip.1 400 Ohm DeJur Potentiometer. 12 Lengths of Bus -bar; Screws, Nuts, Bolts.2 30 Ohm DeJur Rheostats. Free Diagram with Kit.Victoreen Kit alone (4 R. F. Transformers, No. 170; 1 Oscillator Coil, No. 150, and 1 AntennaCoupler, No. 160), $37.00. 24 Hour Service on Shipments.Dealers! Write for Discounts on the Victoreen Super; Silver Six and Silver-Cockaday Parts.

MAURICE SCHWARTZ & SON710-712 BROADWAY, SCHENECTADY, N. Y.

VICTOREEN-OFFICIAL SERVICE

Authorized by Geo. H. Walker Co.Endorsed by Radio World

Victoreen Kits (4 Trans-formers and Oscilla-tor Coil) $33.50

Antenna Coupler . 3.50Meloformer Audio

Transformers 4.01Victoreen Rheostats 1.20Victoreen Potentiometers 1.50Special Baseboard. 1.00Special Bakelite Panel 6.00

With Subpanel and Ra-dion Brackets 15.03

Complete Kits $70 UpWRITE FOR PRICES ON KITS TO

YOUR OWN SPECIFICATIONS,ASSEMBLY, ETC.

H. & F. Radio LaboratoriesPAUL R. FERNALD

1611 Washington St., New York City

WE DISTRIBUTE

VICTOREEN S. H. KITSVICTOREEN POTENTIOMETERS

MELOFORMERTRANSFORMERS

And all other necessary parts. AlsoBrowning -Drake, National Dials,Impedaformers, Choke Coils, etc.

Other lines as well.Paramount Electrical Supply

Co., Inc.132 Church Street New York City

Tone Puritywith

MeloformerEliminate distortion and

transformer noises by In-stalltng kfELOFORME11.the new audio aron110eationinstrument, to your set.Unequaled In volume, toneand range. Send for FreeBooklet A-3, showing Melo-former Hookups.

Robertson Davis Co.420 Orleans St., Chicago

CARTERJacks and Switches

65c

The new Carter"IMP " BatterySwitch Is a quarterturn switch withen "off and on"name plate elearlYIndicating w hen"A" Battery Is"off or on." See

one at your dealers.

Carter Radio CO.300 S. Racine Ave. Chicago