A.AD ITOPICS

MARCH, 1921 A Journal ofHumanInterest

ANNAPOLIS, "NSS ' 500 KW ARCS

15 CENTS

The Heterodyne by .1. J. NovakVacuum Tube Transmitters by Dr. Lee DeForest

My Experiences as Operator on a Limy by F. L. Schoenwolf

SIGN THE SUBSCRIPTION BLANK ON PAGE 18

13(46Y/shed cillo77thi by ,71-7(D C3h7ca'qo Exeou6.ve Council

2 RADIO TOPICS

6%Weee.W.Wee.WWW.W.W.W.WeeeeeeeeeeeeeeMe.W.%%W.WAVANWANWWWW

No. 344 without battery and cord 4.00 No. 12159-W Federal Brass

n

Prompt shipment from stock on all items listed below:Mesco Wireless Practice Sets Price

No. 342 with battery and cord

No. 52 combination practice set

No. 51 Mesco mounted on wood base 2.00 Regenerative Receivers No. 12226 1000 21000 .007 45.00

We are distributors for the following well-known lines: De Forest, Clapp-Eastham, Bunnell, Murdock,Amard, Acme, General Radio, Grebe and Thordarso

Keys

$ 4.50

5.50 No. 1428-W Federal silver platedNo. 47-A Western Elec. Brass

Plugs

$ 2.00Price

2.50 No. 12224 250 10000 .007 $19.001.20 No. 12225 500 14000 .007 30.00

Transmitting Condensers (Dubilier)No.Watts Voltage Cap. Price

4W Quality Radio Apparatus cti-E-56Y

LARGEST STOCK IN THE MIDDLE WEST

No. 80 Mesco /2 K. W. with binding "Grebe" No. 12226A 1000 25000 .007 50.00posts 4.00 No. CR-1 170-600 meters with tube Coils Mountings (De Forest)

No. 12174 C -E buzzer 1.75 detector and two step amplifier

No. 461 1.4 in., operates on 5 dry cells 8.20 plete receiver '10.00 No. U-200 "A" Bat. S !itch & Tel.No. 459 I4 in., operates on 5 dry cells 5.00 No. CR-7 500-20000 meters. LongNo. 460 IA in., operates on 5 dry cells 6.00 wave, with tube control. A com-

Mesco Wireless Sparks Coils

.95 condenser

self contained. A complete set 200.00

65.00 No. ULC-400 Triple coil mounting 5.60No. 8499 Century buzzer 2.50 No. CR-6 170-600 meters. Receiver,

No. ULC-300 Double coil mounting.... 4.80No. 251 Mesco buzzer No. ULC-100 Same as LC -100 but on

No. US -100 Pri. Condenser switch $ 2.50No. US -200 Anti -capacity switch

panelDe Forest Unit Panel Units

, 10.75

4.40

PriceNo. 84 Mesco Y. K. W. without bind- control self containeding posts 3.50 No. CR-2 170-600 meters

$5901..0000

No. LC -100 with gears unmounted $10.00

No. 12021 Boston key, 10 amperes 7.50 170-600 meters 65.00No. LC -101 with gears mounted with

baseNo. 280 Standard -Silver contact points 3.60 No. CR-3 "Special" for relay work.

13.00Buzzers No. CR-3A 170-375 meters. The latest No. LC -201 with base and Pri. switch 15.00

No. 55 Mesco buzzer, 1.5 volts 2.50 Grebe short wave receiver 45.50 No. ULC-200 Single coil mounting 2.00No. 56 Mesco buzzer, 6 volts 3.25 No. CR-4 170-160 meters with series

No. 462 1 in., operates on 6 dry cells 9.00 Audion Control Panels Jack 3.25

No. 463 1,/2 in., operates on 6 dry cells 12.00 No. RO RA Grebe with cabinet 612.50 No. U-300 "A" Bat. Switch .& TelNo. 464 2 in., operates on 8 dry eel's 16.00 No. RORH Grebe with Tick. connec- Binding Posts 2.20No. 495 3 in., operates on 8 dry cells 35.00 tions 17.00 No. UH-100 Crystal Detector 4.30No. 496 4 in., operates on 10 dry cells 57.00 No. P-401 De Forest in cabinet 14.25 No. UR-100 Audion Tube Receptacle 2.95

Prices on larger coils on request No. P-500 De Forest in cabinet with No. US -400 Three point switch 2.25\Vood Variometer Forms, accurately 45 volts "B" battery 25.00 No. OF -200 Filament Bat. Rheostat__ 3.80

tuned, complete set 4.00 Amplifying Transformers No. UCV-500 .0005 MF. Var. Con -Vacuum Tubes No. A-2 Acme mounted $ 7.00 denser 7.75

Audiotron Det. Amp. Osc. (Tubular No. A-2 Acme semi -mounted 5.00 No. U-100 .0005 MF. Var. CondenserType) $ 6.00 No. A-2 Acme unmounted and grid leak 8.50

No. UV -200 Raditotron 5.00 No. 166A General Radio mounted 47..05(1 No. UCS-1500 Bridging or StoppingNo. LTV -201 Radiatron 6.50 No. 166A General Radio semi -mounted 5.25 Cond. 6.25

Tube Sockets No. 166A General Radio unmounted.... 4.50 Coils (De Forest Duo -lateral)N. GR-1 General Radio $ 1.75 No. 12007 Clapp Eastham mounted 6.50 DL -25 $ 1.65No. R-300 De Forest 1.50 No. 12008 Clapp Eastham unmounted 4.00 DL -35 1.70

No. R-400 De Forest Inverted type 2.75 No. 226-W Federal 7.50 DL -50 1.75

Marconi 1.50 No. AA All-American unmounted 4.00 DL -75 1.85

No. 550 Murdock 1.00 Telephones (Pair) DL -I00 1.95Rotary Spark Gaps No. 480 Mesco-1000 ohms $ 7.50 DL -.150 2.10

No. 1,-1 Benwood sound proof $30.00 No. 1 Type C Baldwin's Navy Stand- DL -200 2.20Benwood "Super" Gap 25.00 and 16.50 DL -250 2.30Bellwood Rotors 8, 10, or 14 point 8.00 No. 2 Type E Baldwin's latest super- DL -300 2.45

Rheostats sensitive 20.00 DL -400Perfection back mounting $ 1.75 Brandes' Superior 2000 ohms (new DL -500No. 12474 Paragon back mounting 1.75 type) 8.00 DL -600No. 12475 General Radio back mount- Brandes' Transatlantic 2800 ohms 12.00 DL -750 3.30

ing 2.50 Brandes' Navy Type 3200 ohms 14.00 DL -1000 3.5;

No. 12158-W Federalj N.acksNo. 55 Murdock 2000 ohms 4.50 DL -1250 3.85

P. 2 circuit....$ 1.00 No. 55 Murdock 3000 ohms 5.50 DL -1500 4.10No. 12157-W Federal N. P. closed cir- Variable Air Condensers Antenna Wire

cuit 0.85 No. 1 Chelsea .0012 MF. mounted....__$ 5.00 No. 10177 7 strand No. 22 tinned cop -No. 12156-W Federal N. P. open cir- No. 2 Chelsea .0006 MF mounted 4.50 per per ft. $0.01%

cult 0.70 No. 3 Chelsea .0012 MF unmounted 4.75 1000 ft. or over per ft 0.01

Loose Couplers No. 4 Chelsea .0006 MF. unmounted.... 4.00 No. 14 Hard drawn copper per lb 0.50No. 12054 Clapp-Eastham 2500 meters $14.00 No. 12087 Clapp-Eastham .0006 MF (80 ft. per lb.)No. 335 Murdock 1500 meters 9.00 Balanced type 7.50 No. 1443 7 strand No. 20 Phosphor -

Ground Equipment No. 12088 Clapp-Eastham .001 MF 9.50 bronze, per ft. 0.02%No. 384 100 Amp. 600V. ground No. 12089 Clapp Eastham .0005 MF.... 11.50 500 ft. or over per ft 0.02

switch $ 5.50 Oscillation Transformers InsulatorsWeather-proof No. 4 ground wire ft 0.10 No. 270 Murdock $ 5.00 No. 498 Ball insulator 0.45

I I eavy porcelain cleats with screws for Thordarson 12.00 No. 449 5 -inch strain type 0.55wire, complete 0.12 No. Z-652 Clapp Eastham 1 KW. size 20.00 No. 497 10% inch strain type 1.00

Send for our new Wireless Manual, which contains many pages of general information preparedespecially for prospective amateur radio operators. To avoid receiving a number of requests fromcuriosity seekers and others not fundamentally interested in Wireless, we make a charge of twenty-five (25) cents for this book. Upon receipt of your remittance we will immediately forward youour Wireless Manual together with a 25c coupon which we will redeem for its face value on an in-itial purchase of Wireless material amounting to $5.00 or more.

Manhattan Electrical Supply Co., Inc.114 SOUTH WELLS ST., CHICAGO

NEW YORK ST. LOUIS SAN FRANCISCO17 Park Place 1106 Pine Street 604 Mission Street

.,%%%%Weeeee.VeeeeeMWeMeee%WeeeVWeeWV

RADIO TOPICS 3

I

1

Stop and Consider the Advertising Value of This MagazineHERE YOU HAVE PRESENTED A NEW AND MOST SPLENDID ADVERTIS-

ING MEDIUM THAT GOES DIRECT TO AN ACTIVE BUYING FIELD OF RA-DIOMEN.

OUR CIRCULATION IS RAPIDLY INCREASING, BUT IT IS NOT THE NUM-BER THAT IT REACHES, IT IS THE RIGHT READERS THAT IT REACHES.

IT'S THE QUALITY, NOT THE QUANTITY OF A CIRCULATION THATBRINGS YOU RESULTS.

A well known mail order house put in their first stock of radio apparatus about twoyears ago. They advertised every article in their catalog, which had a circulation of 10,-000,000. They thought that they were reaching everybody and that their poor resultswere natural. They were recently persuaded to advertise in the radio magazines, with theresult that they did more business with this circulation of less than 50,000 one month thanthey had done with their 10 million in two years.

JUST SO WITH ADVERTISING IN RADIO TOPICS; you reach the right FIELDAND GET RESULTS. HERE IS OUR PROOF: JUST WRITE TO ANY OREVERY ADVERTISER IN THIS ISSUE AND ASK THEM IF THEY GET RE-SULTS, OR WE WILL GIVE YOU COPIES OF TESTIMONIAL LETTERSFROM ANY ONE OF THEM IF YOU SO DESIRE.

WE HAVE A CIRCULATION THAT MEANS SOMETHING TO ANY ADVER-TISER AND OUR ADVERTISING RATES ARE MOST REASONABLE. COPYFOR THE APRIL ISSUE MUST BE IN NOT LATER THAN MARCH 16th. RUSHIT IN RIGHT NOW.

Further information can be obtained from

RADIO TOPICS4533 NORTH SAWYER AVENUE CHICAGO

A RAY -DI -CO

"HYLO"

The Double Duty Machine

Supplies the high voltage for the plates. ELIMINATES DEAD storage batteries at criticalmoments. NO MORE troublesome CHARGING, NO SPILLING of ACIDS. One turn of theswitch and you are supplied with the filament current as well as the plate current. The mosteffective operating point of the tube is often dependent upon a critical filament voltage, and adischarged battery may lose you a DX record.

Built in capacities from 30 watts to 175 watts. Voltages from 100 volts to 500 volts for the plates, andfrom 4 to 10 volts for the filaments.

Can be used for receiving circuits, power amplifiers, etc. Special voltages if desired. Prices upon re-quest. When writing state capacities required.

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RAY -DI -CO(RAY -D EE -KO)

RADIO 9 AG

4 RADIO TOPICSig .V..nn*IY.....BR.01.........ff.N1..Pallle.-.1.-.-

Attention Chicago Radio MenThe Chicago Radio Apparatus Co., formerly located at 3400 So. Michigan Avenue, announce

their incorporation and removal to 508 So. Dearborn Street. On and after March 1st we will bein our new loop store and will henceforth do business under the name of Chicago Radio ApparatusCo., Incorporated.

Through the acquirement of greatly increased capital and resources, we will now be able tocarry each and every piece of Radio Apparatus of merit, and our stock will be the largest andmost complete in the Middle West. No matter what you want in the Radio line it can be foundin our new store.

Our retail sales will be in personal charge of Mr. Clarence Klentz, who is without question themost able Radio Salesman in Chicago, and it is with extreme good fortune we have been able to se-cure his services.

Local Customers: We thank you for your hearty support which has made our expansion pos-sible. In our new store you can easily reach us from all parts of the city, and we urge that youcome and inspect our new apparatus without delay. OPEN SATURDAY AFTERNOONS.

Mail Order Customers: We thank you, too, for your trade which has been no small contrib-uting cause of our success. In our new location, with greatly enlarged stock and personnel, youwill secure even more prompt response to your inquiries than in the past.

We will continue to make "Immediate Delivery" our motto, and every order will be shippedsame day it is received.

A new, big catalog will be ready for you soon. Watch for announcement. Send now for com-plete set of Bulletins, free upon request. Blue Print of a complete C. W. Transmitter for 10c instamps. Kindly address all communications to our new store.

"Give us your business; we'll give you SERVICE you will like."

AUDION CONTROLS MURDOCK APPARATUS TELEPHONE RECEIVERSAcme Unit Detector $10.00 Loose -Coupler $ 9.00 Brandes Superior $ 8.00Acme Unit Amplifier 13.00 Aerial Switch 4.50 Murdock, 2000 Ohms 4.50Amrad Unit Detector 15.00 Oscillation Transformer 5.00 Murdock, 3000 Ohms 5.50Amrad Unit Amplifier 21.00 Baldwin, Type "C" 16.50Amrad Detector and One Step 31.50 JACKS AND PLUGS Baldwin, Type "E" 20.00Amrad Two Step Amplifier 39.50 Federal Two Circuit Jack 1.00 Federal, A. & N., 2200 Ohms 12.50DeForest Detector and One Step 75.00 Federal Telephone Plug 2.00DeForest Panel P-401.-...._ 14.00 Western Electric Plug 1.20 BURGESS B BATTERIESGrebe DetectorGrebe Two Step Amplifier

17.0045.00 AMPLIFYING TRANSFORMERS Small 4.5 Volt Units

Small 22 Volt Block.40

2.25Acme, mounted ' $ 5.00 Large 22 Volt Block 3.50

ACME TRANSFORMERS Amrad, mounted (new type) 7.00TA K. W., Fully mounted 16.00 Amrad, semi -mounted 5.00 METERS (GENERAL RADIO)TA K. W., Fully mounted 22.00 Federal 7.50 Ammeters, scale 1, 2, 3, 5 or1 K. W., Fully mounted 33.00 Clapp-Eastham. mounted 4.00 10 Amps., either range 7.75200 Watt C. W. Transformer

50 Watt C. W. Transformer20.0015.00 VT SOCKETS 100 Milli -Amps

250 Milli -Amps11.009.00

Standard DeForest 1.50 Weston Voltmeter, 500 Volt scaleCLAPP-EASTHAM DeForest Panel 2.40 with Resistances, special 20.00Variometers and Dial 6.50 Ace (with Grid Leak) 1.50Vario-Coupler and Dial 7.50 Amrad with Brackets 1.30 VARIABLE CONDENSERSwitch and Contacts to Match 1.50 Amrad, base only .90 "Arco" Panel .001 MF 6.25Aerial Switch 12.50 "Arco' Panel .0005 MF 5.0(1Boston Key 7.50 VACUUM TUBES Connecticut (latest out) 5.00Regenerative Receiver 38.00 Audiotron, 2 filament 6.00 Clapp-Eastham Vernier 6.00

Radiotron UV -200 5.00 Chelsea, .001 MF 5.00RHEOSTATS Radiotron UV -201 6.50 Chelsea Panel .001 MF 4.50Porcelain Base, 6 Ohm 1.00 Electron Relays 6.00 DeForest CV -500 6.00Paragon Panel 1.75 Moorhead Amplifiers 7.00 All types DeForest Vernier at listGeneral Radio Panel 2.50 Moorhead Transmitters 7.50 prices.

CHICAGO RADIO APPARATUS CO., Incorporated508 SO. DEARBORN STREET CHICAGO, ILL.

One-half block South of Dearborn Street "L" Station

PUBLISHED MONTHLY

The Chicago ExecutiveCouncil

W. L. HOLST, ChairmanJ. J. NOVAK, Treas.

N. C. BOS, Sec'y

B. W. STOLTE, Circ. Mgr.J. Q. ADAMS, Adv. Mgr.

4533 North Sawyer Ave.,Chicago, Ill.

DITOPICS

A Journal of Human InterestCopyright, 1921

N. E. WunderlichEDITOR

M. H. RombergASSOCIATE EDITOR

ConsultingAssociate Editors

R. H. G. MATHEWSJ. F. SCHOLTESH. M. ANTHONY

M. B. WESTL. G. PACENTK. E. HASSELC. H. ZELLER

$1.00 a Year CHICAGO, MARCH, 1921 Vol. I. No. 2

Chicago Tribune Installs Radiofor Foreign Press

Beating the Cable Route by Two to Six Hours

EADERS of Chicago dailyIRpapers may be surprised tonote the appearance of for-eign news in the Tribunemany hours before it is pub-

lished in any other paper. This hasbecome possible, much to the chagrinof their competitors, by the installa-tion of radio equipment. Not only isthe broadcasted press picked up, buttheir foreign correspondents now filetheir news for transmission via the newBordeaux station in France. On thecover of last issue was a. photographof the towers of this wonderful sta-tion now signing LY and working onabout 25,000 meters. The signals re-ceived at the Chicago Tribune are au-dible some distance from the receiversand can be recorded on a dictaphoneif desired. The radio transmission beatsthe cable route by anywhere from' oneto six hours.

The aerial is of a loop design, meas-uring seventy by forty feet, and con-sists of twenty wires. The loop issupported by steel supports, which arefastened direct to the steel girders ofthe new building. The lead-ins rundown through large insulators thatwere installed before the building wascompleted.

The loop is right in line with theBordeaux station and is exceptionallydirectional, boats in the harbor just be-low and NUR only a quarter of a mile

distant causing no interference. Thereceiving apparatus consists of a specialconstructed long wave receiver withthree steps of amplification. The wire-less room is entirely shielded andgrounded. Construction and installa-tion was done by the Chicago RadioLaboratory.

The operators must copy the pressdirect with a typewriter and they suredo have to hop along when LY is hit-ting around twenty-five and makes norepeats. At times he will send almostcontinuously for three or four hours. Acontinual watch is kept, as press is re-ceived from some other stations, andthey start at most any time of the dayor night. There being no sending ap-paratus, the operator has to be on thejob every minute and get it all cor-rectly the first time. At the time Ar-gentina quit the League of Nations theset had been just installed and theTribune's correspondent, Lloyd Gib-bons, put this news through by radio,resulting in a clear beat. Not one ofthe other papers knew a thing about it.which only goes to show the practicalviewpoint of radio news service.

Four well known amateurs constitutethe present staff, being Timmy Crow-dus. late of St. Louis; J. F. Scholtes,C. H. Zeller and P. S. Pfeifer of Chi-cago.

On December 18, last year, RearAdmiral Thomas P. Magruder, navalattache to the American embassy in

Paris, delivered to the French govern-ment this station at .Bordeaux, which,by the way, was built by the Americannavy department at Croix d'Hins dur-ing the war to provide better commu-nication with the United States, andpresented by the United States toFrance.

This rather new commercial phaseof the game should present an oppor-tunity to both commercial and amateurmanufacturers in the larger cities, whoare well enough versed on loitg wavereception to make the necessary instal-lation for such newspapers as they areable to sell on the idea.

It will be remembered, however, thatit is almost impossible to hear any ofthe foreign stations during the sum-mer season, which, of course, is some-what of a drawback from a commercialstandpoint, although the fact that anewspaper can get the foreign newsfrom two to ten hours sooner for sayeight months of the year should inmany instances make it well worthcost of installation and maintenance.

There awaits the ambitious radio-man many opportunities to turn hisknowledge into dollars by merely ap-plying it to the commercial necessitiesof the present day. Radio is no longerin the experimental state, and the radiotelephone as well as telegraph is com-ing into commercial use more and moreevery day.

6 RADIO TOPICS

THE AUTHOR ABOARD THE S.S. MAYRO

DAVING had that desire thatall amateur radio enthusiastsare inspired with at sometime or other to be a com-mercial operator on some

boat, I started out by working on thepleasure boats plying between the portson Lake Michigan during the summervacation months. After a few sum-mers of this, during which I must saythat I had some very splendid times,I decided that I would like to try theocean.

According I filed application with theRadio Corporation, and on February13, 1919, I was assigned the berth ofsecond operator on the S. S. Mayro.I was introduced to the first operator,Mr. A. Darlington, a man of wide andvaried experience, who proved a mostpleasant and interesting companion,and we soon became fast friends.

Having a natural curiosity as to howa sea -going vessel looked, I at oncedecided to give it the once-over. Itproved to be a British passenger shipof about 6,000 tons, with passenger ac-commodations for about sixty firstclass and fifty second class travelers.Due to an unusual snowstorm, we wereunable to obtain all of our cargo andwere delayed in leaving some fourdays, during which time I became ac-quainted with all of the ship's officers,who turned out to be very interestingand enjoyable company.

The radio apparatus was naturally ofthat peculiar design that is character-istic of the English Marconi Company.The transmitter was located in theusual British sound -proof room and con-sisted of a 1-V2 KW transformer, oil

My Experiences asRadio OperatorAboard a Limy

The first trip of an American operator and 'ham'

aboard an English sea -wagon

Story and Photos by FRED I.. SCHOENWOLF

immersed condenser, synchronous ro-tary spark gap, block inductance andthe necessary meters. The transform-er drew about 35 amperes, resulting inan antenna radiation of some 5 am-peres. There was also a 10 -inch sparkcoil for auxiiary purposes. The re-ceptor consisted of a British Marconimultiple tuner and magnetic detectors.The multiple tuner worked favorablyand had a range of from 80 to 3,000meters, with the wave lengths cali-brated on the dials. The set was lo-cated in a very fine cabin on the boatdeck. We were assigned to call MFR.

We left New York at noon a fewdays later, and everyone was glad tohe under way, as the weather was get-

ting very cold. Tugs took the ship outof her berth, after which we proceededdown New York Bay under our ownsteam. We cleared the Narrows andthen dropped our pilot at AmbroseLight Ship.

I then began my first watch, and be-lieve me, I got the surprise of my life.Talk about your signals. Why, itsounded like the combined local jam-ming of New York and St. Louis ama-teurs. There were signals of everydescription, and calls of every nationon almost any wave -length. NAH,which is used by Brooklyn, FireIsland, New York City, New YorkHerald, Montauk Point. Sea Gate.Rockaway Beach, Sandy Hook and

We arrived at Grenada (BWI) the following dawn and drifted into the volcanic crater harbor

RADIO TOPICS 7

Montoloking, was heard continually, aswere numerous other nearby stations.There were signals of every descrip-tion and meaning from radio compassbearings to hydrographic reports.Greatly amazed, I spent my first eve-ning listening to this maddening howlof signals.

The next night we started to takemessages, and for the first time in mylife I learned the cable count, so thatI could really understand it myself.The following afternoon signals wereaudible through QRM from Cape Hat-teras (NDW) and Virginia Beach(NCZ). Later in the evening it waspossible to copy NGE through theangry mob.

During the next few nights variousstations would come banging in as wecame abreast, but soon died out as weproceeded, all with the exception ofMiami (NGE). This station wouldcome rolling in so loud that I at firstthought that we were only about ahundred miles distant, but I found thateven when we were directly abreastwith Miami we were some 820 milesoff shore. Just south of this point thereseems to be a sort of dead spot, andwhile traveling through this zone verylittle work can be done. It is rathera strange feeling that comes over youfor the first time when you call somenearby ship and ask for QSR and youfind everybody QS3C. This sensation,however, soon wears off.

A day or so later we came withinrange of San Juan, Porto Rico (NAU),Saint Thomas (NBB) and St. Croix(NNI) of Virgin Island. After sixdays we sighted Sombrero Light andour course was changed to SWS.

From then on we saw numeroussmall islands of volcanic origin, manyof which were inhabited. One of these,known as Saba, is quite interesting,having a population of over one thou-sand. They practically govern them-selves, as no one seems to want thejob. At one time it was owned byHolland, then by France, and finally,as usual, by Great Britain.

We arrived at Grenada (BWI) thefollowing dawn. Drifting into the vol-canic crater harbor with all flags tothe breeze, British Union Jack on theforegaff, British mercantile flag on theaftergaff, house flag on the main mastand U. S. M. and quarantine flags onthe signal halyards, it is indeed a beau-tiful and thrilling sight, which I will

long remember. As we come to ananchorage, numerous native boats comealongside at the gangway to take oneashore. For this they charge sixpence.The passengers pay, but the boat offi-cers don't (after the first time).

In company with a couple of com-panions I proceeded to do a little sight-seeing, with one of the native boysshowing us the points of interest. Thechap that we picked proved quite amus-ing and for our benefit he shinnied up atree fully seventy-five feet high andthrew down green cocoanuts to us.These cocoanuts are not the ones weare familiar with in the States, as theyhave green husks which covers theshell and make them very large. Wealso bought a large bunch of bananasfor a shilling (about a quarter) andhad the boy cart them on board forus. We took a carriage ride throughsome of the various cocoanut planta-tions and were glad to return to theship. At sunset we hauled anchor andproceeded on our way to Port of Spain,Trinidad, ninety-three miles distant.We again reviewed the impressivesights of the Windward Islands, butfor some reason were glad to be onour way to the Island of Trinidad.

Early in the morning. before sun-rise, we sighted Trinidad light, whichguides us to the Bocus of Columbusfame. The Bocus is a narrow channelcutting through the mountains. On oneside is the Island of Trinidad and tothe right is Venezuela. After passingthrough the Bocus, the City of Portof Spain is plainly visible and is onlya matter of a short run. The usualdoctor and pilot come aboard again, asthis is another colony and a paratiqueis necessary. The harbor of Trinidadis very picturesque and incidentallywell protected. The harbor here is veryshallow, making it necessary for us toanchor about two miles out. After thedoctor has examined the passengers,the company's tug takes them ashore.The usual herd of washwomen andlongshoremen then come on hoard. Thewashwomen are fairly reasonable, do-ing up a suit of whites for a shilling.The work is generally satisfactory,even though they occasionally rip ashirt to pieces. Their methods differsomewhat from the American laundry,as they beat the clothes with sticks onrocks and then allow them to bleachin the sun. A white uniform lasts justabout four rounds.

At sunset we hauled anchor and proceeded on our way to Port of Spain, Trinidad

As soon as we anchor the discharg-ing of cargo commences, and as thiswill take some four days to accomplish,we have ample time for sight-seeingand amusements. Port of Spain isat the foot of high mountains, but evenfrom the ship towers of the radio sta-tion VPL are plainly visible.

We went ashore in one of the com-pany's launches, and after passinc,through a warehouse away from thejetty, we came upon a pretty parkwaywhich extends through the entirelength of the city. Within 300 feet ofthe jetty the radio station is located,the spark of which can be heard for ablock. The station shack is surroundedwith barbed wire fence and is guardedby armed soldiers. After going throughthe usual red tape, we were permittedto enter and view the apparatus. Wewere first taken to the transmittingroom. At the time we entered he wascalling Barbados (VPO). and believeme, his spark sonded like a cannon.They do not believe in spark mufflingdown there. The transmitter consistedof a five -kilowatt synchronous com-posite set discharging in open air. Theoil condensers and oscillation trans-formers were about six feet high. Wewere then shown the engine room.Here a large gasoline engine drove aten kilowatt dynamo, generating powerfor storage batteries. The transmitterwas operated direct from these batter-ies, which almost entirely filled a roomtwenty by thirty feet. I believe thatthere were 300 cells in glass carboysin use at the time. The auxiliary wasa duplicate of the one we had on boardthe ship. Lastly we were shown thesound -proof operating room, whichhoused the receiving set and necessarytransmitting meters, switches and cir-cuit breakers. The receiver was of alate design and carried an arrangementwhich was supposed to eliminate static.I guess that they honestly thought thatit worked, too. A vacuum tube wasused as a detector in conjunction witha seven -stage amplifier. The setworked exceptionally well. The bulbswere about one-half inch in diameterand about three inches long, placed ina socket affair similar to a cartridgefuse. They used eight volt "A" bat-teries and thirty-two volts "B" bat-tery. The well known Brown phoneswere in use. The traffic at this stationis very heavy, as they handle all cabletelegraph traffic from British Guianavia BZL and relaying to FKQ thenvia the French cable to United States.Before leaving the station the chiefoperator told us that it would not beof much use to stand watches aftermidnight, as his operators worked sohard throughout the day that theyusually rest at night. The station isowned by the Trinidad and TobagoWireless Telegraph Company, but iscontrolled indirectly by the British gov-ernment.

Leaving the station we continuedour sight-seeing and took a carriageto visit some of the plantations on theoutskirts of the town. A guide tookus to various places and explained thedifferent growths. We saw a numberof caoutchouc trees, from which rub-ber is obtained. I am not sure whetherthese are the trees from which theymake the well known rubber contacts

8 RADIO TOPICS

or not. There is an abundance of bam-boo, which grows in bush style and isthirty to forty feet high. Bananas arealso very common down here. Bananatrees grow from ten to twenty feethigh and, contrary to the general be-lief, the banana bunches hang fromthe trees with the stems hanging downand the bananas pointing up.

We made a number of interestingtrips to the mountains and made shorttrips to the nearby bays. Trinidadboasts of a few large stores and hotels.The stores are of a chain system estab-lished throughout the entire BritishWest Indies and are known as Ste-phen's Ltd. stores.

The Harbor of Trinidad is verypretty and is comparatively cool. Thereare ships at anchor of every type andrepresenting almost every nation. Onthe particular night that we were there,an American Shipping Board vessel,the only American boat then in theharbor, caught fire. This boat, the SS.Balabac (KEGD), had just come downfrom New Orleans with a million anda half square feet of lumber and in-tended to discharge here at Trinidad.The ill-fated ship had three fires in thebunkers, ran short of coal near Bar-bados, ran aground at Bocus Reef,sprung a leak that could not be lo-cated and then finally ended the voy-age by burning to the water's edge.At the time the fire broke out therewas no steam and consequently nolight and, further, no water at thepumps. And besides all this, therewere only four men on board. Thesemen fought the fire until all hopeswere gone and then were rescued by alaunch in the harbor. When all chancesof ever extinguishing the flames wasgone, the Balabac was beached, whereshe burned steadily for two days.

None of the officers or crew of thelost ship had any clothing left exceptthe scant garments they wore at thetime of the disaster. Some of the offi-cers were placed aboard our ship tocome back to New York with us, andin spite of the fact my boat was a Brit-ish vessel with an English crew, whohave little use for Americans, ourbunch got together warm clothes anda collection of money besides.

Some days later we left Trinidadbound for Georgetown, Demerara, B.G., a distance of 365 miles throughrough and shallow water. Two hoursprevious to our departure the RoyalMail steam packet ship Chignecto left,also bound for Demarara. I had quitea "ham-fest" with their operator onthe way down. They were a bit slowerthan we were and we sighted themjust abeam about 5 the next morning.By 9 o'clock we had passed them andwere leaving them far astern. I askedtheir operator if he wanted a tow line,and he came back with "NO" at aboutforty words per. We got in about twohours sooner than they did. The nextmorning we went over to visit themand they proved to be good sports, aswe had a bottle of real English brew tosettle the argument:

We stayed in Demarara only twodays, as there was a longshoremen'sstrike on, with no settlement in view,so we soon turned back. Arriving,however, we docked on the DemararaRiver in the heart of the city. The

THE VAMPIREA fool there was and he went to sea,

Even as you and I.And he choose a life of misery;Though the poets call it brave and free.Yet a fool he was and a fool he'll be,For only a fool will follow the sea ;

Even as you and I.

The life we spend has a bitter tasteWhen we turn again to the land,And the land rejects we derelicts with

our withered mindsAs mental wrecks with a cold disdain-

ful hand.Oh, the joy we lost and the love we lostAnd the light of the home we plannedWas won by the man who stayed

ashore,Who had brains and sense and a whole

lot moreOf the things we never could under-

stand.

A fool there was and his life he spentin a vile life that was never meant

For a thing that God his image lent.But he goes to sea with his own con-

sent;For only a fool knows a fool's content,

Even as you and I.

All that he owns is his foolish hide.That is carefully placed or flung asideTo sink or float on that deep sea tide,Where some of him has lived, but most

of him died.

country here is exceedingly hot, and atnoonday it is impossible to walk about.A nice cool night is about 98 degrees.The shore line here is protected by amassive concrete wall and extends asfar as the eye can see. This is madeinto a parkway, and has numerousbenches where one may lounge aroundand enjoy the cool breezes and soforth.

The radio station here at Demararabelongs to the British government andis quite a large outfit. The antennasystem consists of three large tubularmasts in line, supporting two cageaerials. The spark transmitter is a fivekilowatt composite set similar to theone at VPL. This station works ondifferent wave lengths anywhere from600 to 1,800 meters. The receiving setis of the British naval type and con-tains the usual string of bulbs. In ad-dition to their spark set, they have aten kilowatt CW set, which is operatedon 9,000 meters. The operating staffconsists of fifteen men besides the offi-cers in charge. Prior to the late warthis station had two calls, BZL beingused for naval traffic and VPA forcommercial traffic. Now, however, thecall BZL is the only one used.

After leaving Demarara we returnedto Trinidad, but instead of going toPort of Spain as we previously haddone, we went to La Brea. The pitchlakes, one of the wonders of the world,are located here at La Brea, and it isindeed most interesting to watch theloading of pitch for shipment. Westayed here about three days taking ontwo thousand tons. These pitch lakes,although owned by the British, are

now leased for ninety-nine years to anAmerican concern.

Leaving La Brea we return to Portof Spain and spend three days heretaking on a miscellaneous cargo ofcocoanuts, coffee, nuts, chicle, spices,hides and a few other things. We arenow ready for the return trip.

After leaving Trinidad we return toGrenada for a few hours, and then startback for New York. There is a wholeweek ahead of us, and I spent most ofmy time getting acquainted with thepassengers and indulging in variouspastimes. A favorite sport aboard wasto bet on the total mileage traveledeach day. Every noon a position re-port was posted stating the latitude,longitude, miles per day and the totalmileage. The passengers would bet onthe last number of the miles per day.Being a dollar a chance, it was quiteinteresting.

About two days from New York thepassengers begin to bring up their mes-sages, and then the fun begins. Theyhave in most cases only Englishmoney, and we had to turn in Ameri-can money to the company. Natural-ly, we charged them the additional feefor the difference in rate of exchange.Then you should have heard them raisea howl. Probably the way I figuredthe rate of exchange they had somegood reasons for kicking. I played asafe game, you see. I sure had somejob convincing some of them that Ihad the right dope. The rate changedabout every twelve hours, so I hadto do some neat figuring in order thatI should be nothing out when Ichanged my receipts back into Ameri-can money. However, I don't recallthatl ever got the worst of it. Then Iwould often have some bright nut comeup and file a code or cipher message.As a rule he didn't know what hewanted, and I had to continually beon the lookout so as not to get stuckon any traffic charges.

Approaching New York the firstthing to come in sight is the famousAmbrose Light Ship and then the stillmore famous pilot ship, Sandy Hook.The pilot, upon coming aboard, givesus the latest news of the States, andwe, or rather I, begin to feel at home.The pilot conducts the ship throughthe Narrows, where we stand by forquarantine, immigration and custominspection. We then proceed downNew York Bay. In the distance, onthe New York skyline, looms thethrilling Statue of Liberty. And youcan be assured that it is a grand andglorious feeling to behold once againyour own United States. After visit-ing for a length the foreign countriesand being among the lower element ofthe tropical lands, it is indeed the great-est of thrills to return to such a won-derful country as ours.

After this it is only a matter of ahalf an hour of excitement before wedock. Friends rush aboard to welcomehome the arrivals . . . . but nosuch happy welcome awaits us, nogreetings, no cheers. But it's only fora moment, and it's all in the game.

I, in concluding, should say that I,an American radio operator, have madenumerous trips aboard a British "LimyWagon," and I will never regret theseeventful trips. The worldly experiencegained is well worth while.

RADIO TOPICS 9

Radio Telephone and TelegraphTransmitting Apparatus

IRECENT progress in the de-velopment of the oscillion orvacuum tube type of radiotelephone equipment hasbeen most marked since the

war. The requirements have increasedso that at the present day it is neces-sary to manufacture many differenttypes to meet the demand. This isgreatly due to the fact that the radioamateur has taken up radio telephonyseriously, so that continuous waveequipment is rapidly replacing the old-fashioned spark apparatus. It is alsobecause commercial organizations re-quiring communication facilities tooperate their business have at lastbeen convinced that the radio tele-

phone has been developed to a com-mercial stage and is no longer experi-mental.

"A"-Panel No. 1, Type OT3

The De Forest Company at presentis manufacturing transmitting setsranging from 5 watt input to an inputof 4 KW. These equipments have tele-phone ranges of from 1 mile to 500miles and telegraph ranges up to 2,000miles.

The smallest set manufactured isknown as the type OT -5 "BuzzerRadiophone." This consists of a smallpanel containing two rectifier tubesand an oscillator tube of the VT type.The power supply for this set is ob-tained from two 6 -volt storage bat-teries. One battery takes care of thefilament supply for the tubes and theother provides a source of power tooperate a double vibrator buzzer of thespark coil type or direct current trans-former. This buzzer delivers a poten-tial of 1,000 volts at the terminals ofthe secondary coils, which is an alter-nating current of pulsating type. Thiscurrent is automatically put throughthe rectifier tubes to deliver a fairlyconstant pulsating D. C. to the oscil-lator tube. The transmitter is pro-vided with a relay control switch for

By DR. LEE DE FOREST

This is the first of a series ofarticles to be written for us bythe well known Dr. Lee DeForest.

Because of the increasing num-ber of bulb transmitters, it ishoped that this article will be ofsome benefit to those interestedin CW.

Dr. De Forest will very short-ly give us an article on station2XX and also some informationon the more recent developmentsof the radio telephone.

transferring the aerial from the receiverto the transmitter, as is the case withall types of transmitting equipmentmanufactured by the De Forest Com-pany, with the exception of the verylargest sets.

The latest addition to the De Forestfamily of transmitting apparatus is thetype OT -3 "Midget Radiophone." Thislittle outfit illustrated herewith ismounted on a panel only 9 inchessquare and is capable of producing re-markable speech over distances up tofifty miles. This 3 -tube equipment iscomplete in every detail, even to thetransfer switch, and may be connectedto any power supply designed for thetubes that are used. This equipmenthas an advantage over other types ofDc Forest equipment in that the tuningis accomplished by means of tapswitches on the face of the panel, sothat a very sharp resonance point maybe easily obtained with corresponding-ly increased efficiency. The "MidgetRadiophone" is made -up of two separ-ate panels, each 4J/2 by 9 inches in size,which are linked together by meansof the connecting straps. This inno-vation in design allows the experi-menter, if he so desires, to purchaseonly the tuned aerial circuit panel tobe used with tube receptacles, rheo-stats, etc., that he may have on hand,with the idea of purchasing the tubeunit at a later date to complete theequipment.

"B"-"Midget Radiophone" Type OT -3

The type OT -10 "Radiophone" is a30 -watt set, well known in the amateurfield. This equipment, together withthe type 0 alternating current radio-phone, has been on the market now forsome time, and it is rare than an ama-teur listens at his station of an eve-ning now without hearing at least oneof these types at work. The illustra-tion shows how the four oscillatortubes are mounted on the face of thepanel. The control button for the re-lay transfer switch is near the bottomat the left, with the control rheostatsfor the filaments of the tubes above it.Meters are provided for registering thefilament plate and Antenna currents,and tuning is done by means of thegrid condenser and Antenna series con-denser with control knobs on the faceof the panel. The helix, modulation

"C"-Panel No. 2-Type OT -3

transformer, grid leak, filter coils andcondensers are mounted in the rear.

The type 0 "Radiophone" is identi-cal with the OT -10, except that thepanel is longer, as it contains in addi-tion two rectifying tubes. A trans-former for supplying the power ismounted on the base in the rear. Thistype of "Radiophone" is to be discon-tinued shortly in favor of the OT -10with a rectifier cabinet, designed to beplaced directly beneath the former.There will be no difference as far asthe operation of the set is concerned,except that a new filter system hasbeen worked out for the rectifier cabi-net, which is an improvement over thefilter in the present type 0, in that itreduces the A. C. hum to practicallya negligible quantity.

The De Forest Company also makesa type OT -20 "Radiophone," which isidentical with the type OT -10, exceptthat it employs eight oscillator tubes

(Continued on page 16)

10 RADIO TOPICS

Elementary Electrical PrinciplesLearn them well, apply what you learn and you will be a better radioman

and have a more efficient station

XN last month's issue ofRADIO TOPICS the writerattempted to impress on theradio enthusiasts the greatnecessity of studying the

science of radio telegraphy in a system-atic manner. Unless the amateurs usethis method of procedure no gains willever be made and the underlying prin-ciples will be, misunderstood, simplybecause of neglect.

It is the purpose of this article, whichwe will call lesson 1, to introduce themost fundamental ideas dealing withthe electric circuit. If the student whois about to enter into wireless will readand study each succeeding article in athorough fashion, he will soon find him-self well equipped with sufficient train-ing to advance from the simple to thecomplex.

The first thing we should devote ourattention to is the basic laws govern-ing the flow of electricity in power cir-cuits. We assume that electricity issomething which is always present,which is around about us at all timesin what may be called a stationaryform. Now, the most important thingwhich is necessary is to create somemethod of making this electricity move.We may to a mass ofwater in a lake. The water is there,but if we wish to make it move in orderto obtain from it power, we must applysome pressure to bring about thismovement. Take, for example, thewater in your river or your well. Howare you going to get this water fromthe river or the well up to your house,which is located several miles distant?It must be admitted that pressure isnecessary, so in the case of water wemust apply a pump to force that waterthrough the pipe. So is this true withthis great big reservoir of electricity,and then if we provide a suitable chan-nel through which it may be conducted,current will flow. This we will call theelectric current. The pump which isused in pushing electricity through thischannel is called the electric generator.The generator will drive the currentthrough the wire just as the waterpump drives the water through thepipe. This electric pressure apparatusmay be a dynamo, or it may be a bat-tery. We will confine our attention atpresent to the former and allow thebattery to be taken up in another les-son. In the case of water the pressureis reckoned in terms of pounds; that is,so many pounds of pressure. In thecase of the dynamo we reckon the pres-sure in terms of VOLTS. It is ob-vious that if we have 100 volts appliedto electricity that the current will flow100 times as fast as it would if we onlyapplied 1 volt (provided we use thesame size conductor and retain thesame length). If 100 volts will not passthe necessary current through the con-ductor, then we will have to increasethe voltage or pressure up to the properpoint when the required current valuewill be reached. In cases where trans -

By 11.112k 1.1 MITCHELL ANTHONY

Here, fellows, is a wonderfulopportunity to learn somethingof value. Mr. Harvey M. An-thony, a consulting electricalengineer and expert radioman,has written a series of six les-sons, one for each month. Atthe end of each lesson will beten questions that you are toanswer after studying the ar-ticle. Answer each one carefullyand neatly and mail at once toMr. H. M. Anthony, Muncie,Ind. He will mark your paper,and the next month we will pub-lish a list of those that passed.Then, at the end of the six les-sons, those that have beenabove grade every month willreceive a beautiful certificate,certifying your knowledge, andsigned by H. M. Anthony, E. E.,and our engineer.

It don't cost you a cent; thereis no red tape. Go to it and wina certificate.

formers are used for wireless sendingis usually applied.

and the ordinary pressure under theseconditions is approximately 110 volts,this being the common house lightingvoltage in most cities.

Now, assuming that we apply this110 volts pressure to an electric cir-cuit, a current will flow. However, wemust be able to regulate this current,for too much of it will burn out ourapparatus. Voltage is only one of theconsiderations which determine thecurrent strength. Probably the mostimportant is electrical resistance. Re-sistance is without doubt the most gen-eral property of all power circuits andshould be carefully studied by the stu-dent. In the case of water flowingthrough a pipe, the water must actual-ly move from point to point, from thepump to the receiving end, where itis to be used. Wherever the body ofwater moves the channel throughwhich the flow takes place offers moreor less opposition to the flow. Thatis, the water pipe has certain propertieswhich will regulate the flow to a largeextent. It is plain to be seen that ifthe pipe is small in diameter the flowwill not be as easy as it would werethe pipe of large cross-section. Thepipe also has an inside surface uponwhich the water rubs when flowing,and this inside surface will offer moreor less opposition. If the pipe is twiceas long (and of the same area) it willoffer twice the resistance. Hence wefind in the flow of water this importantfactor of opposition offered to the flow.In electricity we find exactly the samething. The unit of electrical resistanceis the OHM. In electricity we dealwith wires just as in water we dealwith pipes. Wires have certain proper-ties and the laws governing electrical

resistance in these wires will be ex-plained briefly as follows:

(1) The electric current is con-ducted through a wire and not alongits surface. Thus a wire having twicethe cross-sectional area will carry twicethe current. The larger the wire theless will be the resistance offered tothe current flow. The smaller the wirethen the greater will be the resistance.Wire sizes are rated in circular mils.The circular mil is the area of a wirewhose diameter is one mil (one -thou-sandth of an inch). A number 14Brown & Sharp wire is one having across-sectional area of 4107 C. M. Anumber 6 B. & S. wire has a cross-sectional area of 26250 C. M. Thuswe can plainly see that the No. 6 hasover six times the area of the No. 14,consequently the resistance of the No.6 will be about one -sixth that of theNo. 14. By increasing the size of awire we can reduce the resistance. Thisfactor of resistance is very importantin radio circuits, and unless we watchit pretty carefully trouble will ariseand our circuits will be inefficient. Theadvice is to make the resistance as lowas possible by using wire of the propersize.

(2) The resistance of a conductoris directly proportional to its length. Awire, say a No. 14, has a resistance of2.5 ohms for every 1,000 feet of length.If the line is made 2,000 feet long, thenthe resistance will be doubled and theactual resistance will be 5 ohms. Onthe other hand, if only 100 feet of thiswire is used, the resistance will be one -tenth of the thousand foot resistancevalue, which will be one -tenth of 2.5ohms, or 0.25. It is my advice to thewireless man to make his power leadsas short as possible, thereby reducinghis resistance.

(3) The resistance of a conductordepends largely upon the material withwhich the conductor is made. A silverwire would really be the best conductorwe could use, but unfortunately thecost of silver prevents us using it inour radio circuits. The next hest con-ducting material is copper. Copper iswhat we employ in our electric lines.A pure element is, as a rule, a betterconductor than an alloy. Silver is thebest, copper next, aluminum next, ironnext and German silver last. Theseare materials out of which conductorsmight he made. Iron has about sixtimes the resistance of copper and Ger-man silver has about twelve times theresistance of copper. For this reasoniron and German silver are both usedfor making resistance coils. for theyoffer considerable opposition to thepassage of electric current. Resistance,being so important in radio work, de-serves a lesson in itself, and such a les-son will be considered later.

(4) The resistance of a conductordepends largely upon the temperatureof the wire when the current is flow-ing. As a wire becomes warmer its re -

(Continued on page 15)

RADIO TOPICS 11RA.....116..

Editorial Expressionsand Timely Comments

Everybody's University

HERE are radio amateurs inthis country who talk inter-terestingly and wisely andthere are others who talkdully and stupidly.

There are fellows who know what isgoing on in the radio game and intel-ligent enough to speculate about thereasons for it.

There are fellows who take a liveinterest in radio and radio organiza-tions who think wisely and act wisely.

These are the interesting fellows thatyou like. They are interesting becausethey know what is going on. Andthey know what is going on becausethey read the radio magazines.

The magazines are everybody's uni-versity. No one need be uneducatedif he will read the magazines carefullyand intelligently.

They present to you periodically thelatest developments and happeningswith comment on them, if you care forcomment.

They give you the biographies of allmen who have accomplished things.They tell you of all the inventions thatare made in the field, of all progress inradio science and education.

The man who reads the magazinesand thinks about what he reads willsoon be an educated man. He willtalk intelligently because he will thinkintelligently. A radio education con-sists to a large extent of a knowledgeof the daily happenings, and there isno way in which this knowledge canbe gained so easily as by discovery ofwhat is going on and why.

All able statesmen, all interestingwriters and all experts in any line arecareful students of the publicationscovering their individual field. And itis the magazines which are the re-corders of events wherein you shouldstudy.

When a fellow tells you that hemerely looks at the pictures and skimsthrough a magazine and is weariedwith the mass of details published, youcan well set him down as a stupid per-son. When you hear someone talkwisely about the latest radio develop-ments and affairs, set him down as acareful reader of the radio publications.

The magazine that scours the coun-try for the latest material and eventsthat you may know all is a better uni-versity and a greater source of knowl-elge than anything else you are likelyto ever find. Make use of it and youwill have no excuse for continuing inignorance.

It seems almost incredible in thesedays that there should exist any busi-ness houses who are not thoroughlyconvinced of the inestimable value ofpublicity.

The Upward TrendIn radio, just as in any other tech-

nical art, progress and improvementis exceptionally rapid, and with suchprogress goes the modification orelimination of past and present meth-ods and equipment. The advent ofCW transmission as a practical factorin the amateur field is beginning tomake itself felt as an actual feature ofrelay communication. We do not be-lieve that CW will supersede sparktransmission any more than the in-vention of the telephone and its pres-ent stage of development has affectedthe telegraph. Each has its propersphere of usefulness and each mustfunction in co-operation with theother. Our A. R. R. L. relay routeshave heretofore been formed almostaltogether of spark transmitting sta-tions only. Spark communication is atits worst in summer weather and un-der daylight conditions. CW seems toovercome these difficulties, partially,at least. CW, however, has the dis-advantage of being so sharp as tomake calling without .pre -arrangedschedule futile.

The ideal combination is that ofspark for calling and ordinary work,and CW for transmission throughstatic or spark interference, or underabnormal conditions under whichspark transmission is difficult. Asmore and more of our better longdistance stations add CW transmit-ters to their equipment our alreadyestablished routes approach this idealcondition. These combination routesare already in practical operation fromthe north to the south and from theeast to the west boundaries of ourCentral Division:

Messages are being handled con-sistently over two well-defined routesof this type, the first being from Min-neapolis to St. Louis via 9X1-9XM-9ZN-9PQ-9XZ-9ZB, etc. The firstfive stations on this route have bothspark and CW equipment. The eastand west route runs from Minneap-olis to Salem, Ohio, from which Pitts-burgh and New York connections aremade. This route runs via 9XI:9XM-9ZN-8ZG, all of which are dual -equipped. These routes have func-tioned properly on daylight tests andhandle traffic with exceptional easeunder normal conditions. Our LeagueTraffic Manager is endeavoring to es-tablish chains of this type throughoutthe country, and we look forward withmuch interest to the time when"QSY-CW" will become universal.

Our Service Department has studiedthis question at considerable detailand can advise you as to the designand construction of apparatus where-by your station may become dual -equipped and may participate in thepresent rapid advance in the radio art.

An Open Letter From the New 9thDistrict Radio Inspector

The new radio inspector of theninth district has been in office inChicago but a short time but he hasalready strung an aerial and installeda calibrated receiving set at which hehas been .spending quite a bit of histime lately and which accounts for thefact that he is very much put out overthe way some of the amateurs are dis-regarding the government regulations.Quite a number have been heard usingunofficial call letters and others whodo not use the entire call,

This must be corrected and all sta-tions should sign fully at least oncefor it can be appreciated that theremay arise a time when it would be ofvital importance to get into wire com-munication with a station which wouldbe impossble unless it could be identi-fied through its call.

There can now be no excuse for notfollowing this rule and the Councilas well as the inspector will find itnecessary to prosecute any future vio-lators.

DEPARTMENT OF COMMERCENavigation Service

Office of Radio Inspector 629 Federal Bldg.,Chicago, Ill.

February 18, 1921.Editor Radio Topics, Chicago, Ill.

Sir: It has come to my attentionthat a great many amateurs are vio-lating a very important Radio Lawwhich carries a very heavy penalty.

This law, which every amateurshould know, is given below. Anyviolations of it that come to my atten-tion will be dealt with accordingly.

"Sec. 7. That a person, company, orcorporation within the jurisdiction ofthe United States shall not knowinglyutter or transmit, or cause to be utter-ed or transmitted, any false or fraudu-lent distress signal or call or false orfraudulent signal, call, or other radio-gram of any kind. The penalty forso tittering or transmitting a false orfraudulent distress signal or call shallhe a fine of not more than two thou-sand five hundred dollars ($2,500.00) orimprisonment for not more than fiveyears, or both, in the discretion of thecourt, for each and every such offense,and the penalty for so uttering ortransmitting, or causing to be utteredor transmitted, any other false or frau-dulent signal, call, or other radiogramshall be a fine of not more than onethousand dollars or imprisonment fornot more than two years, or both, inthe discretion of the court, for eachand every such offense."

Any amateur who signs any callother than his own call is violatingthe above law whether he is licensedor not and a few examples will bemade of those who are caught.

Respectfully,L. R. SCHMITT,

I.RS/S U. S. Radio Inspector.

RADIO TOPICS

The Heterodyne for Beat Reception andC W Transmission

Some very helpful information on the construction and operation of aheterodyne generator

the recent World Warleft a trail of woe and de-struction, still it also bene-fited humanity in manyways. One of the depart-

ments of human endeavor to be agreat gainer was mechanics, which in-cludes, of course, "radio." Under thestress of the war, the French govern-ment conceived the idea of the"Heterodyne" for beat reception andC. W. transmission. This apparatus,upon America's entry into the war,was used by the Signal Corps of theA. E. F. in the absence of their reg-ular equipment. The distinct advan-tage of the Heterodyne is that, withthe same hook-up, it will function aswell for Beat reception, when placedalongside of your receiving appara-tus, as for straight C. W. transmis-sion when connected to your aerialand ground.

On this side of the water, my curi-osity to experiment with the Hetero-dyne was aroused when, during a visitto a friend, I noted that he was ex-perimenting with the Heterodyne for

03DCItof

0

i1.1.11*

Heterodyne Circuit

the production of beats for undampedreception, At this time he was using,if I am correct, an Audiotron tubeand 80 volts on the plate.

When using this circuit for localoscillator in your radio room, an 0to 5 milammeter of any known makecan be inserted in series with the gridand inductance to indicate whetheror not there is a flow of oscillations.Usually about 1 to 3 milamperes aresufficient.

Some amateurs may want to knowif their tube or tubes are generating.This may be ascertained by watchingthe needle of the milammeter, as thisis a factor of paramount importancein this type of apparatus. If yourmeter does not register, it is evidentthat no transfer of energy (oscilla-tions) can be had to the receiving ap-paratus. This may be remedied asfollows:

1. By replacing your tube or tubes(if more than one are used, as in theFrench Heterodyne two tubes wereused). Your tubes may have provento be very soft. This will be indicatedby a blue glow.

2. By replacing your tube or tubes,which have proven very poor oscil-

By J. J. NOVAK, A. M. I. R. E.

lators. These will have to be replaceduntil dependable ones are found.

3. See that all four prongs makegood contacts with their respectivepoints on the socket.

4. Make certain that all your con-nections are soldered well, and thatheavy wire is used for them.

By experimenting with the follow-ing tubes, it was noted that those hav-ing a high vacuum were very easy as-cillators. While those with an inter-nal gas were not, each carrying thestated amount of milamperes on thegrid:

Type ofTube

ca"0

-6,)

ao

4 .V141

0r.n 0

V. T. 1 Moorhead 3- 5 145 .0005V. T. 2 Moorhead 6- 8 145 .0005V. T. 1 West Elec. 15-18 145 .0005V. T. 2 West. Elec. 20-25 145 .001U. V. 201 Radiotron 4- 4.5 145 .0005Audiotrons (Non-oscillators-too soft)Electron Relays " 0

U. V. 200 Radiotron " 0

Description of component partswhich are necessary in the construc-tion of the Heterodyne.

Inductance - Was wound with 28turns of No. 18 code stranded fix-ture wire (green silk covered), upona bakelite tube, with an outside diam-eter of 5 3-16 in. having a 3-16 in. walland 2% in. wide. The inductance wastapped in the center and ends. Fur-ther tapping of inductance is at thediscretion of the constructor.

Condenser-A C. V. 500-90 degreeDe Forest type of condenser wasfound upon experimentation to be bestsuited for this class of construction asa .0012 mfds. Chelsea would permitthe electrostatic electricity, which ac-cumulated thereon, to jump across.

Socket-The "Ace" v. t. socket wasused, as it easily dismantled. Thebase from same was used as a tem-plate for the drilling of the new holesfor panel mounting.

Rheostat-A General Radio rheo-stat was used, due to its easy work-ing when mounted on panel.

This concludes the description ofapparatus needed for the construc-tion of the Heterodyne. Although thediagram above shows all tubes beingworked with 145 volts on the plate,80 volts will suffice for any of theaverage tubes that are available forthe amateur's purchase on the openmarket.

Operation-First, connecting both"A" and "B" batteries to their re-spective binding posts, as these areall the external connections that arenecessary. Second, bringing up thebrilliancy of your filament with therheostat. Third, the tube when prop-

erly heated will start a flow of oscil-lations within, and this in turn willmake the milammeter to indicate theamount. Fourth, to confirm this, sim-ply by touching any of the metallicparts of the shunt condenser, grid orplate contacts, will cause the meterreading to drop. This is stated, thatin turn that anyone experimentingwith any of the "soft tubes" will getthem to oscillate, but upon touchingthe metal parts the tube will stop os-cillating and the meter reading willdrop. Then the process will have tobe started over again.

Straight C. W. TransmissionA whole chapter could be devoted

to the principles of the Heterodyneand beat production, but this muchcan be said, that when you are receivingfrom a station whose frequency is inthe neighborhood of 500,000 cycles,and in order to receive this, our Hete-rodyne would have to generate in thevicinity of 499,000 or 501,000 cycles.By varying your condenser any notepleasing to the ear can be had.Changing of condenser changes your

Transmitting Circuit

wavelength, and this in turn controlsthe flow of oscillations for that par-ticular wavelength, as each wave-length has its own frequency.

Without the use of the Heterodyneyou would not hear any of these par-ticular frequencies, as they are aboveaudibility.

A lot has been said about the He-terodyne, the amount of apparatus itrequires for its construction, but any-body who constructs one of these"little mystery boxes" will naturallycare to take up the transmission ofsignals with the same circuit.

The writer has constructed a two -tube transmitter, employing 145 voltson the plate and has covered 30 mileswithout the least trouble from QRM.In fact several of those parties whohave had the fortune of conversingwith the writer have had the same re-sults. On one case, especially, it canbe enumerated; at this particular sta-tion there was in use a /2 k.w. non -synchronous spark set. These signalscould not be heard fifteen miles away.On the other hand, signals from asingle tube C.W. set employing 90volts on the plate, carried thru withoutthe least exertion, and were reportedvery QSA. The writer himself, can

(Continued on page 17)

RADIO TOPICS 13

fluess what I you win tin: oil-inunerseil spark gap

CHE photograph here aboveprobably looks to you likea thousand things that itisn't, and we would feel per-fectly safe in offering one

of the latest oil -immersed spark gapsas a prize to anyone that could tellwhat it was. However, as we donot care to be bothered with runninga picture puzzle contest, we are goingto let you in on it right away.

Here's the dope. It's one of the morerecent radio sets developed by the Ger-mans and employed on their sub-marines. The photo was taken by ourfriend, Jimmy Crowdus, late of St.Louis, and more lately operator at theChicago Tribune station. We don'tquite recall how he explained obtain-ing the picture, but believe it wassomething to the effect that he had cap-tured this German submarine one dayduring the late war with the aid ofa newly designed direction finder. Wedidn't follow the details of his explana-tion very closely,as we don't believe iteither. We do know, however, that hehas the outfit with the exception of thetransformer at his home, as we saw itwhen visiting there during the St.Louis convention.

Those handles on either side are notcontrol or change -over switches, as yousupposed. They are simple wavechangers, the one on the left be-ing the primary of the oscillation trans-former and the one on the right thesecondary. By moving these theamount of inductance is varied and anywave length can quickly be obtainedas a calibrated scale is mounted along-side. The transformer, not visible inthe picture, is rated at 2 KW and isoperated at five hundred cylces, which,in conjunction with the quenched gapshown, gives a wonderful tone. Justbelow the gap is a hot wire ammeter.And you should see the key. It musthave been made for some great bigHun to hammer with his foot.

The photo was taken and the appa-ratus "salvaged" while Crowdus wasin the navy. No, this is not the setlie used while signing 9ZV.

A technical lecture is delivered everyFriday night at 8 p. m. by radio tele-phone from NSF. It is sometimes re-peated at 10 o'clock. The lectures arevery well delivered and contain somevaluable material. Get your set oscil-lating on 375 meters and copy him ifyou can write shorthand.

Topicsof the

Day

Second District Radio Show andConvention

The Executive Radio Council of theSecond District will hold an immenseradio show and conventionat the HotelPennsylvania, New York City, March16, 17, 18 and 19, 1921. There willbe plenty of lectures and actual dem-onstrations of every kind of equipment.The roof garden of the hotel will beused for the manufacturers' exhibitsand the adjoining Butterfly room asthe lecture hall.

The first three days will be devotedto business and the last day to generalsociability. The big banquet will beheld the night of the 19th. and reserva-tions may be had at $3 per plate. Theconvention will be open to everybodyfrom 2 p. m. to 10:30 p. m. daily.

This convention is being held underthe auspices of the Second DistrictCouncil and Mr. J. 0. Smith will pre-side as chairman. It is non-partisanand non-sectarian, with everybody wel-come. Those desiring banquet ticketsor exhibition space are requested towrite the council at 6 Warren street,New York.

The CW fad has at last struck Chi-cago. What next?

Have you made arrangements withyour boss to have a week of your vaca-tion at the time of the First NationalRadio Convention at Chicago August30, 31 and September 1, 2 and 3, 1921?If not, better do it now, for with allthis time to plan you can have no goodexcuse, and further, you surely wouldnot want to miss the first national as-semblage and show ever held. If youattended the Chicago convention lastyear you have some idea as to whatyou can expect; if you weren't thereyou will just have to take our word forits splendor and good times.

We understand that Boettcher, 9KN,has a daylight schedule with NSF. Bet-ter use the mail service, KN, at leastthat has the advantage of getting theresome time.

Wouldn't you like to have a certifi-cate indicating that you knew the prin-ciples of electricity as applied to radio,signed by a well known consultingengineer, as well as the magazine staffengineers? Then why not enter in theinstructive course being given by Mr.Harvey M. Anthony. Turn back to iton page 10.

Ohio Radio Conference March 5thA conference of all Ohio radio men

will be held at Columbus, Ohio, onMarch 5, 1921, under the auspices ofthe Columbus Radio Club.

A large majority of the Ohio fel-lows will be present and invitation isextended to all of the Central Divisionmen. Reservations should be madeimmediately with Mr. R. C. Higgy, 92East Frambes avenue, Columbus Ohio.

Quenched Gap Squad to the FrontIn an effort to prove the possibility

of reducing QRM by the more exten-sive use of quenched gaps and lowerpower, the American Radio and Re-search Corporation is offering free dur-ing the month of March one Amarad

K.W. quenched gap with the pur-chase of every induction coil.

In addition, on every Wednesday andSaturday during March the various sta-tions using these quenched gaps willsend out a broadcast to prove theirworking ability. The stations whichwill send out the QST messages arelisted below, together with the time.

Eastern time.1X E 4:30 p. m.1GY 9:00 p. m.10J 9:10 p. m.lAK 9:20 p. m.1FW 9:30 p. m.2CX 9:40 p. m.2PL 9:50 p. 111.

8AIW 9:10 p. m.Central time.

8ZZ 9:15 p. m.5XG 9:30 p. m.811G 9:45 p. m.9ZH 9:50 p. m.

Pacific time.6HI 9:30 p. m.

Here's Your Chance to be a RadioDetective

A broadcast furnished by the Dallaspolice department will be sent out from5 ZC each evening at 7 and 10 p. m.This broadcast will contain informa-tion of value to the various police offi-cers within 150 miles of Dallas, Texas.Amateurs within this territory are re-quested to copy and deliver this infor-mation to their local police department.The advantage of reaching a largenumber of officers with a single trans-mission is of great value, providing allthose that can possibly do will co-oper-ate.

14 RADIO TOPICS

"KDKF" Is Call for Doctor at SeaMedical advice by radio, designed to

save life in event of sickness or accidentat sea by applying proper treatmentuntil personal service of a physician orsurgeon can be obtained, is now pos-sible.

A new emergency call, the letters"KDKF," has been established whichwill rank in importance with the dis-tress signal, for it means that individuallife is in danger and assistance is beingrequested.

A recent arrangement between theSeaman's Church Institute of NewYork and the navy department estab-lished a school of medical instructionfor officers and seamen. Marinerstrained in this school, if called upon totreat a serious illness or accident caseat sea, can communicate by radio tothe physician at the institute and re-ceive from him instructions to be fol-lowed until the ship reaches a harborand secures assistance. The medicalofficer in New York is "on watch" from2 to 10 p. m. for this service.

The company formerly known asYoung & McCombs is now dealingas the Karlowa Radio Corporation,Rock Island, Illinois.

The Everyday Engineering Maga-zine has been indefinitely suspendedand their radio editor, Mr. M. B.Sleeper, is now president of the Gen-eral Apparatus Company.

ARE YOU DOING IT?Boost RADIO TOPICS, boost your

friend;Boost the club that you attend;Boost the street on which you're

dwelling;Boost the goods that you are selling.Boost the people round about you.They can get along without you;But success will quicker find themIf they know that you're behind

them.Boost every forward movement,Boost for every new improvement,Boost for the man for whom you

labor,Boost the stranger and the neighbor.Cease to be a chronic knocker,Cease to be a progress blocker;If you'd make RADIO TOPICS

better,Boost it to the final letter.

Whoever Brung Him in Brung HimOut

Deer Eddy: Ay yust now got dasdarn CW erase und bye yimany it suredrive me nuts. First I sell my sparkmaker und bye das bulbs und hardrobber pannel und also I bye me dasonedam generatum. I bain connect dasonedam yunk to gedder already tentimes und das goshding yunk still vontwork. Von't you pleese give me dasconnect up in das next monts RadioTopics. A couple ov guys yust hearund tell me dat by generator iss burntout. I know dat und vat difference duzdot make? Ven das next guy says tome "CW" he vill go to das under-taker und get das wodden sute. Sohoping you are das same.

Guud bye,Axel Svede.

The Dallas Automobile Club is alsooffering a $50 reward for the arrestand conviction of auto thieves. Thereis a chance for you to get in on thisreward. Local police within 150 milesof Dallas who might be interested inthis are asked to write to Police andFire Commissioner L. E. McGee, Dal-las, Texas, who has endorsed this plan.

RADIO TOPICS is trying to giveyou the best radio material that thereis; what is your contribution? Theleast you can do is to show your appre-ciation through a subscription. Turnover to page 18 and mail in the blankright now.

There is something of importance onpage ten. Better read it over.

Good will flows from mutual respectand friendship of clubs crystallizesaround the opinions of their members,who come into closer radio contactwith each other through the medium ofthis magazine.

Stop'And before you do

another thingSign the

Subscription Blankon Page 18

Surely it's worthOne Dollar a Year

Yes indeed, Luke, it sure keeps afellow busy these days traveling fromone radio convention to the next.

Read 'Em and WeepIn the golden chain of friendship

there is many a missing link.

A fellow finds it easy enough to getalong once he gets started downhill.

A woman speaks volumes with hereyes and whole libraries with hertongue.

It is a waste of time to find faultwith yourself. Plenty of people willdo it for you.

No, Luke, family jars do not comeunder the head of bric-a-brac.

Cupid is a wise little chap. He leadsthe couple to the altar, then quits thegame.

It is a good deal easier to wean a calfthan to wean the United States Senatefrom the consideration of weird radiobills.

Little "Kick -Backs" with a MoralBe dependable. If you make a prom-

ise keep it and be fair to the other fel-low in the air. Courtesies are morepleasing when wholly unexpected;don't argue with the traffic manager.Fellows on 300 meters are like moon-shiners-flirting with trouble.

It is the worst kind of luck to havetoo little wit to talk well and notenough judgment to knew when tokeep still; some hams seems to haveplenty of this kind of luck.

"I Will' is the switch that regulatesself-control-watch your sending.

There are no prizes for those afraidto dream; nor for those who lack theenergy to wake from their dreams andwork.

As we have no classified advertisingspace and as the following is of con-siderable importance to the welfare ofa fellow radio man, we are publishingthis ad under this column. Radio menhaving sisters that they think wouldmeet with approval are requested tosend in photograph With full details.

WantedA pretty, blue-eyed, bobbed hair

blonde, about five feet four, neat andattractive, residing at or within motor-ing distance of Chicago. Further par-ticulars can he obtained by writing"ZN, WO," care of Radio Topics.

We wish to take this opportunityto thank our many new subscribersfor their kind letters of congratulationand wishes of success. It is indeedgratifying to know that the first issuemet with such splendid approval, andwe regret that we were unable to ac-knowledge all of the splendid corres-pondence with personal letters, buteveryone is assured of our hearty ap-preciation.

A good many of the fellows seem tohe of the opinion that CW is not get-ting through, but we think that thisidea has become prevalent because ofthe fact that very few ever allow theirreceiving outfits to oscillate. We haveheard of cases where the fellows hadthought that the resonant "click" thatthey heard just before the oscillatingpoint was caused by a short circuit intheir set and they would immediatelydetune. You will be somewhat sur-prised at the number of `CW sets thatare in the air these fine nights.

Everyone knows of the fact that CWis extremely sharp because it has nodecrement and because of this commu-nication has been quite difficult. How-ever, RADIO TOPICS' engineers havedevised a simple scheme to broaden acontinuous wave and still not give itany decrement. Sounds funny, weknow, but it's so, just the same. It isbeing experimented with at the pres-ent time and full particulars will hepublished at a later date.

An organization should be formedcalled the W. V. U. (Wave Violators'Union). Not a bad idea, is it, 8UX?

No, Luke, the bird that you hearsigning "GB" is not telling all thosefellows "good-bye" continually; the"GB" in his case happens to he "GlaceBay."

RADIO TOPICS 15

NO TICKETS NECESSARY FOR THIS SHOW BY RADIOOne of the most novel and interesting stunts that has ever been

heard of is a contemplated theatrical performance by radio. Mr. R. F.Gowan of the DeForest company is arranging to give a show to theamateurs via the radio telephone at station 2XX, New York. Heplans to have the well-known Duncan Sisters, who have made sucha hit with their singing in Fred Stone's musical play, Tip Top, nowplaying in New York, give a song review, and hopes to have a num-ber of comedians and a jazz orchestra complete the performance.

Get this now, fellows. The date is not altogether definite, butit is hoped to hold the show on the night of Sunday, March 13th, 9o'clock, Eastern time, 10 o'clock Central time. It will be given by Mr.Gowan from station 2XX, radiophone on 400 meters. You are re-quested to stand by and listen for the performance and report by mailif you hear it. 9ZN, Chicago, may possibly automatically retransmitthe affair with his phone set. It's a great stunt, fellows, a real showby radio, and you should not miss it. At 11:30 p. m. each night 9ZNwill send out the latest plans on this and give you the definite date ifthe above should be changed. Stations 2XX, 2ZM and NSF will alsobroadcast this information.

"GETTING OUT.' EVIDENCECalls Heard Here, There and

EverywhereHeard at 8ML, Cleveland, 0.

1AW, 1BBL, 1DA, 1HAA, 1RAY,2AER, (2BB), 2BGH, (2BP), 2CK,2DA, 20A, 2RK, 2TF, 2TS, 2UC,2ZM, 2ZN, 3BP, 3DH, 3EN, 3GO,3HJ, 3ND, 3PU, 3SW, 3XF, 3MI.4AL, 4AU, 4BQ, 50D, 5DA 5YE,8ADF, 8AJI, 8AJW, 8A H K, 8BC,&BP, (8CG), 8DV, 8FD, 8FE, 8FT,8GB, 8GI, 8FIF, 8HG, 9IH, 8IV, 8JI,8JS, (8KM), 8LG, (8MF), 80J, (8RQ),8SH, (8SP), 8TF, 8WY, 8XE, 8XK,8XU, 8YK, SZD, 8ZE, 8ZG, 8ZL,8ZU, 8ZY, 9AAW, (9AAV), 9AEG,9ALA, 9ARG, (9BP), 9CP, (9EQ),9ET, 9FN, 9H N, 9HR, (9HT), 9HU,(9KB), 9KL, 9K0, 9MC, 90E, 90X,9SH, 9UH, (9UK), 9UU, 9WU, 9YE,9Y I, 9X11, 9LB, (9ZL), (9ZN), 9ZQ,9Z V.

ELEMENTARY ELECTRICAL PRINCIPLES(Continued from page 10)

sistance increases. Thus. when youoverload a conductor and pass morecurrent through it than it can safelycarry, the resistance value rises great-ly, according to the temperaturereached. In many forms of electricalpractice temperature is a very impor-tant item and must be safely guardedagainst or considerable loss of energywill arise.

Therefore, in planning electrical cir-cuits we should be careful to observethe foregoing points; namely, wire size,wire length, kind of wire and heat de-veloped during the flow of the current.A proper consideration of all theseitems will result in higher efficiency ofthe complete radio circuit, which willconsequently mean greater energy out-put. Energy output is that which allamateurs are interested in, and theabove stated principles will apply inwireless from the source of voltagesupply clear through the circuits to thevery extreme end of the aerial.

The relationships existing betweenvoltage, current and resistance areshown in the following formula knownas Ohm's law. This law is the funda-mental law governing the flow of theelectric current in conductors, andwithout the law electrical engineeringtoday would be unable to solve thegreat problems placed before it. If youas a student are well acquainted withthis little bit of mathematics you willbegin your first step toward the suc-cessful and practical solution of prob-lems in electrical work.

The unit of pressure is the VOLT.The unit of current is the AMPERE.The unit of resistance is the OHM.

VOLTS=AMPERES x OHMS.E

Where E is equal to the voltage orelectromotive force; I is equal to cur-rent intensity (in amperes); R is equalto resistance (in ohms).

It is advisable for the student tolearn this formula as quickly as pos-sible and also learn how to appyl itto circuits. A good way to learn theformula and remember it is by the fol-lowing method: Place the E over theI x R thus, E . Nov if you wish

I x Rto find the current, place your fingerover the I in the formula and you haveE divided by R. Then solve yourproblem by using the numerical valuesfor I and R. In the same manner, ifwish to find the resistance, place yourfinger over the R and you have theE divided by I. If you wish to findthe E, place your finger over the Eand you have I multiplied by R.

The following problems should beworked out by the student. Make prac-tical use of the above formulas:

1. What voltage is necessary toforce a current of 5 amperes througha coil of wire which has a resistanceof 24 ohms?

2. What current will flow throughthe filament of an incandescent lamphaving a resistance of 58 ohms, whenthe applied voltage is 116?

3. How much resistance is there inan electric stove if the current regis-tered by the ammeter is 4 amperes andthe house voltage is 110?

4. A generator is supplying 220volts to a lamp which has a resistanceof 44 ohms. How much current willthe lamp receive? Suppose the resist-ance remains constant and the voltageis cut down to 110. Then how muchcurrent will pass through the lamp?

Answer the following questions:1. Explain what you mean by elec-

tric pressure and give its unit.2. Explain what you mean by elec-

tric current and give its unit.3. Explain what you mean by elec-

tric resistance and give its unit.

4. What effect has the pressure orvoltage on the flow of current?

5. What effect has resistance on theflow of current?

6. Name the various factors whichdetermine the resistance of a conduc-tor carrying electricity.

7. Why is it not advisable to usetoo small wire when installing a line?How would you determine the propersize wire to use?

8. Where in your radio transmittingset must you be careful about wiresizes and what will happen if you over-look this?

9. What is the best material usedfor wires to carry electric current otherthan silver. Why use this material?

10. What is meant by a circular mil?Where is this term used in electricity?

In the next issue an article will ap-pear taking up a further considerationof the flow of current in conductors.The radio students who are interestedin these articles are requested to sendin their answers on the above problems,and questions to the writer for grad-ing, and those amateurs who studycarefully all this work and submit cor-rect answers will receive honorablemention each month in RADIO TOP-ICS. RADIO TOPICS will also pre-sent each amateur with a certificateof proficiency after each six lessonsare completed. It is necessary thatthe students submit their lesson sheetsregularly and within one week afterthe issue of RADIO TOPICS is intheir hands after leaving the press.

GET BUSY AND LET'S SEEWHO RECEIVES HONORABLEMENTION IN EACH MONTH'SISSUE. ADDRESS YOUR ANS-WERS TOHARVEY MITCHELL ANTHONY,

HIGH SCHOOL BUILDING,MUNCIE, INDIANA.

16 RADIO TOPICS

Efficiently ) tl I )ktril,iited Capacity Eliminated Scientifically CorrectThis instrument is

the result of manymonths of the mostscientific experiment-ing in an effort todepart from the con-ventional design ofvariometer construc-tion. The absence ofdistributed capacitymakes this the MOSTEFFICIENT variom-eter on the markettoday.

Calibration Curvesfurnished with eachset.

Write for descrip-tive information bul-letin "T."Price as shown in

above illustration$6:50

With Amrad Knobsand Dials $7.00

Other types cf knobsPATENT APPLIED FOR and dials extra

Standard design Variocoupler $7.00We are agents for AMRAD, C. R. L., Benwood, Pacent Electric Co., General Radio,

Clapp-Eastham, Acme, Thordarson, BALDWIN PHONES, Brandes Phones, Wimco.Radiotrons, Morehead Electroc Relays and Amplifier Tubes, Paragon Rheostats, Burgess,Eveready and American "B" Batteries.RADIOLECTRIC SHOP, Dept. "T," 919 Huron Road, Cleveland, 0.

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If not, the trouble is most likely === in your voice transmitter= =

Get a Skinderviken Transmitter Button and =your troubles will be over. A special model has Ebeen developed for radio telephone work whichhas many splendid features. As there is no pack-ing of the carbon granules it gives a clear and =sharp articulation of the voice. The button will

$1.00 Prepaid stand heavy currents and they may be arranged= in multiple where the current is too great for one.

It has hundreds of applications in all branches of sound transmission and= - there are many thousands now in use all over the world.

RADIO $1.00 LOCA I, BATTERY $1.00

J. SKINDERVIKENInventor and Sole Manufacturer

154 West Randolph Street CHICAGO, ILL. (Mail Orders only)Retail City Sales:

MONARCH STATIONERY CO. Come in and see us 123 N. La Salle St., CHICAGO

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RADIO TELEPHONE AND TELE-GRAPH TRANSMITTING

APPARATUS(Continued irons page 9)

instead of four, with a correspondinglyincreased output. Like the OT -10,power is furnished by means of a smalldynamotor, delivering 500 volts to theplates of the tubes.

The larger members of the De For-est Radio Telephone family are pro-vided with standard /2 Kw. oscilliontubes. These tubes require a plate vol-tage of 1,500 and a filament current of9 amperes at 15 volts. This line ofhigh power equipments has been builtaround these tubes, using one or moreas the case requires. The type OT -101, /2 Kw. set is identical, for in-stance, with the type OT -201, 1 Kw..equipment, as pictured herewith, ex-cept that one tube instead of two isemployed. 'These equipments consistof a transmitting panel, together witha power panel, the former beingmounted in cabinets one above thelatter. A 3 -unit power plant is pro-vided, consisting of a driving motordirectly connected to a generator unitconsisting of two generators, one forthe plate supply and one for the fila-ment supply. These generators arespecially compounded to deliver ratedvoltage with large load fluctuations andare controlled by means of field regu-lators and switches on the power panel.The power panel also contains thestarting box for the driving motor andmeters for indicating the voltages de-livered by the generators.

The transmitting panel contains thenecessary equipment for emitting radiotelephone speech, buzzer modulatedtelegraph or C. \V. telegraph signalson three different wave lengths. Theaerial circuit is tuned by means of astep by step series aerial condenserand clip adjustments on the helix, whileclip adjustments also take of the grid -plate coupling. The clips are con-nected by means of leads to a wavelength change switch and a couplingswitch on the face of the panel, so thatany of the three wave lengths may im-mediately be used tor either telephoneor telegraph without opening the cab-inets and making adjustments on thehelix. The aerial transfer switch maybe operated manually by means of alever on the face of the panel or elec-trically by a push button in the handleof the microphone. It is also operated

HERE IS YOUR FIRST OPPORTUNITY TO SECURE A SUPERIOR

OSCILLATION TRANSFORMER

SPECIAL TYPE "S" $20.00RAVENSWOOD RADIO DISTRIBUTING CO., Manufacturers and Distributors

1917 WARNER AVENUE TELEPHONE WELLINGTON 1678 CHICAGO, ILLINOIS

Our products are all that perfect oscillation transformers should be. Of neat anddurable construction, they are designed to meet the present need of a correctly builtand easily adjusted transformer even while sending. A feature of importance is the factthat it is impossible for the ribbon to dislodge itself from the mounting.

The ribbon is of brass mounted on bakelite strips which in turn are placed on aheavy brass center piece supported by hardwood cross strips. Electrically and mechan-ically, they are built right.

Our regular Type R oscillation transformer consists of four turns of 2 in. ribbonon the primary and eight turns of 1 in. ribbon on the secondary. The diameter of theribbon spirals is 18 in. over all. This transformer will improve any station.

Price $16.00, f. o. b. Chicago.There are cases where a larger oscillation transformer is required because of higher

power or wave -length, and we have therefore designed a special Type S which consistsof four turns of 3 inch ribbon on the primary and 12 turns of 1 inch on the secondary.It has been found that by the use of three inch ribbon on the primary, the antennaradiation has been considerably increased over that obtained with a smaller one. Wemake no guarantee of this fact; however, one of these Type "5" oscillation transformersis now a part of the standard equipment of station 9 ZN. This, indeed, is a splendidpiece of apparatus $20.00, f. o. b. Chicago.

RADIO TOPICS 17

electrically by means of a switch onthe key block for telegraphing. Thekey block contains also a secondswitch for changing the circuit fromC. W. transmission to buzzer modu-lated transmission.

The 1 -Kw. set has a commercialrange of 200 miles, and with 200 -footaerials distances up to 1,500 miles havebeen covered experimentally. This setis designed to operate on wave lengthsbetween 300 and 1,000 meters on anaverage antenna and puts out as muchas 7 or 8 amperes under favorable con-ditions.

The 2 and 4 -Kw. sets or types OT -401 and OT -801 are built up in twopanels similar to the 1 -Kw. sets. Theradical difference, however, is that thetubes are placed in racks in the rearof the panel and not on the face. Thewave length is changed by means ofone control knob, which operatessimultaneously three independentswitches mechanically linked together.The largest or master switch changesthe aerial connection, while the othertwo switches control the grid -platecabling. These large equipments aremade in two types, one for telegraphonly and the other for telegraph andtelephone. In the latter type a speechamplifier is used to deliver heavier po-tential changes to the grids of thetubes.

With the entry of manufacturingorganizations into the field of radio asconsumers rather than producers ofradio equipment, it is apparent that thetrend in development is for larger andlarger stations, capable of coveringgreater distances. It is apparent fromthis that a revolutionary change inradio transmission is taking place, andit will be but a short time before thewail of the old-time spark set will dis-appear from the radio atmosphere.

THE HETERODYNE FOR BEATRECEPTION AND CW TRANS-

MISSION(Continued from page 12)

confirm this statement with his ownapparatus, as upon initial operation,this same station came back, with allof the conventional abbreviations thatcould have been thought of.

From the writer's standpoint, theonly reason that more C.W. sets arenot employed, is because of the sharp-ness in tuning, and the regenerativehook-up that must be used in orderto receive these signals.

The diagram as shown below shouldbe used with this same circuit for C.W. transmission, with a few slightchanges.

1. Placing a small condenser (fixedor variable) in series with antennalead-in. This is to keep your antennafrom sapping your tube, as the oscil-lations generated are very small. Evenplacing your finger on the antennalead-in will sap your tube.

2. Connecting your ground and keyas shown in hook-up you arc readyfor transmission. The condenser againcontrols your wavelength, and this isthe only change that is necessary forQSY'ing to another wavelength. Nosignals will be heard, and no milam-peres will flow (if one is used in thegrid) until the key is closed.

A set of 30 No. 703 Eveready Flash-light batteries were used by the writer,

A -AAmplifying Transformers

Give Greater

Amplification

Audio Frequency

MOSTEFFICIENT

HIGHESTQUALITY

WE ARE GLAD TO ANNOUNCE THE FOLLOWING LOWERED PRICESCOMPLETELY MOUNTED, AS ILLUSTRATED. $5.00UNMOUNTED $4.00SEMI -MOUNTED (UNMOUNTED WITH MOUNTINGUNASSEMBLED) $4.50

SHIPMENTS MADE FROM STOCK PREPAIDSATISFACTION GUARANTEED OR MONEY REFUNDEDWE OFFER ATTRACTIVE PROPOSITION TO DEALERS

USED AND SOLD BY CHICAGO RADIO LABORATORY, CHICAGO

ALL-AMERICAN ELECTRICAL MFRS.815 S. WISCONSIN AVE., OAK PARK, ILL.

ENGINEERS-MANUFACTURERS

Order Direct from this Ad.Electron Relay $ 6.00Amplifier and Oscillator 7.00Transmitter 7.50Audiotron double filament 5.00Paragon Reostat 1.75Murdock V. T. Socket 1.00DeForest V. T. Socket 1.50Acme Amplifying Trans 5.00Federal 2 -circuit Jack

651..0000Grebe CR3 Relay ReceiverBaldwin Phones Type C 16.50Single unit for Loud Talker 8.50

DeForest Duo Lateral Coils.Send 10 cents for DeForest catalog.

Send stamp for latest bulletin.Mail Orders promptly filled.

Open Monday, Wednesday and Friday evening, 7 to 10; Sunday morning, 10to 12:30.

Liberty Radio Supply Co.6802 ABERDEEN STREET CHICAGO, ILL.

SPECIAL TUNERS5000 M to 20000 M-$10.00-add P. P.-Type700 M to 5000 M- 10.00- add P. P.-Type300 M to 700 M- 10.00-add P. P.-Type

These tuners need no advertising asthey are used all over the world.

KNOCKED -DOWN CONDENSERSAssemble them and save money

11 Plate $1.8021 Plate 2.2541 Plate 3.20 Add P. P.If you want us to assemble them for you add $1.00, plus

P. P., to above prices. Shipping weight 2 lbs.SEND 10 CENTS FOR CATALOGTRESCO, DAVENPORT, IOWA

B.

A.

C.

S.

S.

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18 RADIO TOPICS

"JUPITER"Shipping weight

Discount to

allows your transmitter energy toradiate from a broad surface ofpure copper at a minimum re-sistance. Seven strands No. 22solid copper. Strong and flexible.High conductivity plus 100% radia-tion.11/2c Per Foot-$12 Per Thousand

15 lbs. per thousand. Send check or money order. No C. 0. D.'s.Clubs, Colleges and A. R. R. L. officials. Immediate delivery.

LEE A. BATES 8 Moen St. Worcester, Mass.

FREE!!ALimited number of copies of the latest consolida-

ted RADIO CALL BOOK have just reached us.WE will send you a copy

absolutely FREE OFCHARGE if you send us$2.50 for a 15 months' sub-scription to

PACIFICRADIONEWS

YOU save $1.50 on thisexceptional offer. All

orders must reach us nolater than April 30. Copiesof the Call Book sent post-paid. If you are not inter-ested in this offer please tellyour radio friends about it.

IF YOU ARE ALREADY A SUBSCRIBERWHY NOT EXTEND YOUR SUBSCRIPTION?The new PEN BRAND grid condenser or the PARKINpanel mounting rheostat given FREE with a one year sub-scription. Add 10c for postage. Subscription rate $2 a year

PACIFIC RADIO PUB. CO.50 MAIN STREET SAN FRANCISCO

THE FIRST ISSUE OF RADIO TOPICSWENT LIKE WILD -FIRE

Hundreds of letters of congratulations were received and not asingle complaint.

The dealers' demands were far beyond our expectation, and inorder to insure your recepit of the coming issue, subscribe at once.

We think this live, snappy, interesting, helpful magazine is worth$1.00 of anybody's money, don't you?

Send your answer on the coupon below.

DateRADIO TOPICS,

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If you do not find in Radio Topicsthe service or article that meets yourparticular requirements, or you havesome special desire in mind; or, if youwant to know of proper sources of sup-ply; or want to know of some ques-tion, we can and will gladly help you.Please state your desire explicitly.

Of course, there is no charge for thisservice. It comes to you as part of theservice of our magazine that is trulyrepresentative of our interest in thecomfort and welfare of our readers.

For information write to SERVICEBUREAU, which will personally helpyou solve your problems.

Radio Topics4533 N. Sawyer Avenue

CHICAGO, ILL.

and these have not shown the leastdepreciation. It can be said that thedrain on the batteries is very smalland equal to shelf life of the batteries.

A set similar to this described hasbeen constructed, the only deviationbeing the substitution of a 0 to 50ityilammeter and a C. S. .1000-.001infds. 180 degree De Forest variablecondenser. By setting the condenserat 21 degrees on scale, and using an80 ft. "T" antenna 27 ft. lead-in andground a wavelength of 275 meterswas obtained. This condenser settingalso indicated the maximum flow ofoscillations within the tubes.

In testing for a maximum flow ofoscillations, aerial and ground discon-nected, key closed, and tubes burn-ing, varying the condenser a humpwill be passed where a maximum in-dication will be observed by the mil -ammeter.

In conclusion, if any more informa-tion is desired, the writer can bereached by addressing direct to theEditor of Radio Topics.

Our friend, Murphy, 8ML, of Cleve-land, writes requesting an article on"How to get the power company toput in a special line for less than $100."Can anyone oblige us?

He also informs of a very uniqueway of finding your polarity whencharging a storage battery. Connectyour line to the battery for chargingand then connect a lamp across thebattery. If it brightens up when chargeis on the polarity is correct. If itdims the polarity is reversed. Quitesimple.

We were unable to publish the pro-ceedings of the Chicago ExecutiveCouncil, as we had promised, but weassure you of their appearance at alater date. Lack of space also madeit impossible to print a couple of otherarticles that we had intended for thisissue.

RADIO TOPICS 19

Amplification WithoutDistortion

The increasing use of radio telephony as well as group frequency tuning in spark transmissionrequires maximum amplification with an absolute minimum of distortion and annoying noise.

This result can only be obtained by careful design and construction, with due attention to thedetails which mark the distinction between an ordinary amplifier and the Amplifigon.

All our Amplifigon Detector and Amplifier Control Cabinets are guaranteed to operate with-out distortion or "squealing," and the degree of amplification defies comparison.

AMPLIFIGON-AGN-1 AMPLIFIGON-AGN-2

"Z-NITH11Radio Apparatus Mark of Highest Success

AMPLIFIGON-AGN-3

OUR NEW BULLETIN, F-21, OUT MARCH 1st, DESCRIBESALL OUR LATEST DEVELOPMENTS

The Chicago Radio LaboratoryOffices 1316 Carmen Ave. Testing Station /N. 5525 Sheridan Rd.

CHICAGO

BUY FROM RADIO EXPERTS

THE NEW BELL ROTARY (QUENCHED) SPARK GAP

1-Special Aluminum Alloy casting.2-Small hysteresis loss.3-Low decrement.4-Short leads.S-Balanced Rotor.

printed on high-grade

ADVANTAGES OF THE "BELL" ROTARY GAP6-Four Adjustable Electrodes. When ordering, state whether 6, 8, or 127-Glass windows for easy adjustment. electrodes are desired. We can furnish spe-8-Hardened and ground shaft.9-Bronze Bearings. cial rotors with the gap, for which extra

10-Oil Ring Lubrication. charge will be made.PRICE $55.00, PREPAID

BUILD YOUR OWN S. W. R. RECEIVERWhy pay as high as $85.00 for a S. W. R. when you can build your own with little

only at one-fourth the cost?VARIOMETERS, P. or G., complete with Pointer, Rod, BUSHINGS, large Knob, etc. Ready for

PriceVARIO-COUPLERS, complete with Pointer, Knobs, Bushings, SWITCH POINTS, SWITCH, etc

mounting. PriceAll Points and Outside Bushings are of polished nickel. All parts soldCABINETS-Standard size for S. W. R. Finished in oak. Price

We also supply Polished Bakelite Panels to fit S. W. R. Cabinets.

SOMETHING NEW!

RFl1l101LOG:

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and isinches.

Send for this valuable book, which will add new pleasure toyour work. Introductory price $1.50.

Why not start the year right bykeeping a good and completeLog of your experiences in send-ing and receiving? A good Loghas come to be a necessity in amodern Radio Station, and yourstation cannot be complete with-out it. A great deal of time hasbeen spent in developing thisLog, and everything is arrangedin a logical and orderly manner.Each page contains a tabulatedform with proper headings.There are also several chartsupon which you can easily makecurves and other records that willgive you at a glance some factsof your work over a period oftime that will be both interestingand valuable.

The book contains 100 pagesbond paper. The size is 8/ x 105A

separately. Prices quoted

trouble and

panel mounting.$7.00

Ready for panel$5.00

upon

RADIOTRONSRadiotron U. V. 200

is a Detector and Au-dio Frequency Ampli-fier of unusual capabil-ities, which operatesfrom a single standardplate battery. Best de-tector action occurs atplate voltages between18 and 221/, volts, witha filament current ofapproximately 1 am-pere, and with a gridcondenser and gridleak. U. V. 200 is par-ticular] y adapted toamateur regenerativecircuits. A trial in suchcircuits will be themost convincing.

Price $5.00.

WRITE AND TELL US YOUR REQUIREMENTS

application.$5.50

RAVENSWO OD RADIO CO.2044 WAVELAND AVE. C HICAGO,ILLINOIS