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P.A. Techniques For The Commg

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Servicing Photo -

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RADIO SERVICE DEALER * OCTOBER, 1949

EDITOR I ALby S. R. COWAN

Long Beach RTA in NewsLong Beach California's Radio Tech-

nician's Association has a spark -plugmember named Harry E. Ward. I've knownand worked with Harry for years. He isdynamic, sincere, and successful. That initself commends him, but in addition,Harry has been "association conscious"and in my humble opinion the West Coast'sservicing profession owes him a debt ofgratitude for his many contributions tothe art. Now we congratulate Harry forhaving won the Archie J. Mooney Awardbecause the technicians apprenticeshipcommittee voted him the "most outstand-ing, aggressive member" in connection withhis efforts to improve service quality andlabor standards in his part of the country.In every key city of the country it would

well if an aggressive Service Dealerwould step out and dominantly, yet judi-ciously, attempt to organize his fellowtechnicians into a local association so theycan progress in unity towards the goal ofimproving our profession's status in thatparticular community.AM Versus TV Potential

Over 3 million TV sets are now in usein but a few highly populated areas whileover 80 million home and auto radios arein use in the country as a whole. By 1953it is estimated that half the country'shomes will have TV sets, and of course,it is likely that the number of AM setsin use will not diminish. However, receiv-ers break down in direct proportion tothe amount of usage they get, and statisticsalready show that where there is TV thenumber of service jobs on AM sets isfalling off alarmingly.

An average TV set is equivalent to 7AM sets in breakdown potential, numberof replacement components, etc. The labortime required to repair a TV set, as com-pared to an AM set, runs upwards of 10to 1., So, while the servicing profession cananticipate being kept busy handling AMmaintenance work for many years, we cannot discount the much greater money-making potential TV offers to technicianswho are competent enough to service thecomplex TV circuits.

Never lose sight of the fact that "Timeis Money" to a repair profession. Wastedtime is money lost, and never regainable.No matter how long it may be before TVreaches your community, take advantage ofthat very fact by learning NOW all thereis to know about this new Art.Servicemen Winning Recognition

From all branches of the radio industry,manufacturing and broadcasting included,at last is coming the rightful recognitionso long overdue the servicing profession.Now, if both the manufacturers' andbroadcasters' associations would utilizetheir strong prestige and publicity dis-semination positions in educational cam-paigns to teach the set owning public thatit can have confidence in established andreputable Service Dealers, all partieswould benefit.

Sanford it. CowanEDITOR st PUBLISHER

Samuel L. MarshallMANAGING EDITOR

COWAN PUBLISHING Corp.342 MADISON AVENUENEW YORK 17, N. Y.

Vol. 10, No. 10

OCTOBER, 1949

Editorial 2

4Field Findings

Trade Flashes 10

P.A. Techniques For The Coming Elections, by C. A. Tuthill 15

Practical suggestions on the installationand operation P.A. this type.

The Kay Megaliner, by Allen Lytel 18The second of this series covering theKay TV alignment instruments.

TV Quiz No. 5, by David Gnessin 20

Servicing Photo -Electric Equipment, Part I, by William R. Wellman 21Theory and installation of photo -electricdevices. First of two installments.

Sixteen Inch Conversion Kit, Walter H. Buchsbaum 23Describing the operations of converting a standard 10 inchreceiver for use with the new 16 inch tubes.

Circuit Court 25Detrola Model 61I -A, Crosley Model 9-102,Hoffman Model C-503

New Products 26

Association News 35

SANFORD L. CAHN HARRY N. REIZESNational Advertising Sales Manager Advertising Manager

JEAN M. WHEELER, Circulation Manager DAVID SALTMAN, Production ManagerBRANCH: J. C. GALLOWAY 816 W. 5th St., Los Angeles 13, Calif., Mutual 8335RADIO SERVICE DEALER is published monthly by Cowan Publishing corp., 342 Madison Ave.,N. Y. 17, N.Y. Subscription price: $2 per year in the United States, U.S. Possessions & Canada;elsewhere $3. Single copies: 25c. Entered as second class matter Dec. 13, 1948 at the PostOffice at New York. N.Y. under the Act of Mar. 3, 1879. Copyright 1949 by Cowan Pub. Corp.

2 RADIO SERVICE DEALER OCTOBER, 1949

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RADIO SERVICE DEALER OCTOBER, 14493

31211 indinqAA resume of Industry happenings here, there and everywhere

THIS month "Field Findings"will be reported in reverse chro-

nological order, starting with last min-ute doings, then going back step bystep to the point where I left off in theAugust issue.

Telecasters Educational CampaignTBA (TV Broadcasters Assn) and

RMA have jointly released a seriesof 20 TV movie shorts. These runfrom 20 seconds to 1 minute and willbe furnished gratis to all of the,81 TVstations now in operation so they mayrun them during available "stationbreaks".

Each movie short tells the teleview-er how to properly operate his set formaximum enjoyment. The basic pur-pose behind each is to try to reducethe number of unjustified "callbacks"which have plagued TV installationand maintenance firms. Having seenthe previews of the series of educa-tional shorts, I would say that mostare very effective and in the mainwill help the servicing fraternity. Iparticularly liked those "shorts" whichwarned TV set owners not to fiddlewith alignment controls; not to tryto install their own antennas, etc.,and instead to call their local ServiceDealer. If nothing else, the very factthat RMA and TBA are going aheadwith the project proves that at longlast the service technicians are beingrecognized as being an integral partof this industry.

However, as a passing thought, Iwould also urge RMA to work withAM broadcasters in lining up a seriesof station break announcements forAM listeners whereby AM audienceswould be reminded to have their radiosets checked periodically by the localService Dealer. After all, there arewell over 80 million AM receivers inuse, and a large percentage of themare not in good operating order butcould easily be put in good conditionif serviced for a nominal fee.

RCA Tune -Up CampaignTaking a leaf from our recent edi-

torial suggestion, RCA has come upwith a fine campaign intended to help

by S. IR. COWAN

Shown above are some of the RadioService Dealers who attended thePRSMA Service Convention at TownHall in Philadelphia, on Sept. 18, 19,and 20. Almost 5,000 were there.The Radio Service Dealer MagazineBooth can be seen in the top pic-

ture at the extreme right.

Service Dealers get more repair jobs.RCA estimated that well over 10 mil-lion radio sets in homes require re-pairs. Accordingly a complete "kit"has been made available to provideService Dealers with sales and mer-chandising aids so they can go afterthe potential business. There are win-dow and store displays, direct-mail'and other advertising pieces, evenplastic price stands. All the materialhas the theme of teaching set ownersthat it will not cost them much tohave their sets repaired. Nice going,RCA. Let's hope that other manufac-

turers will afford Service Dealers withaids of various types that will helpthem keep hammering at the setowning public to have their setschecked regularly. Most Service Deal-er organizations are small, one ortwo -man establishments, that cannotafford to pay for expert advertisingguidance. The big manufacturers canand should make such material avail-able-and the servicing fraternitywould be wise in utilizing it.PRSMA Service Convention a SmashSuccess

Sept. 18, 19 and 20 were bannerdays in Philadelphia, Pa. The Phila.Servicemen's Assn. put on a 3 -daytechnical clinic as a fore -runner to"Preventive Radio MaintenanceMonth" which runs all of October inboth the Keystone and Empire (NewYork) States.

The Convention, held at Philadel-phia's Town Hall, opened at 5 p.m.Sunday the 18th. Addresses of non-technical nature were given that nightby key figures from the Jobbing, Man-ufacturing and Broadcasting fields;all pointed out that the importantposition of radio -TV technicians isfinally recognized. Then, the redbusiness got under way at 10 a.m. onMonday the 19th when the technicallectures began.

It happened that I was designatedto act as Master of Ceremonies forthe two days of technical sessions.What a job it was! The attendance.figures prove my point. There werealmost 500 seats available in the lec-ture hall, and at every session allseats were filled with hundreds stand-ing in the jammed packed place. Also,hundreds of others were millingaround in the Exhibit Booths, lookingat the new items being shown. Im-agine, during the two and a half day"show" 4443 men registered in at-tendance, and of these over 2200 wereservicemen and technicians, somecoming from cities over 200 miles dis-tant from Philadelphia.

The "show's" success can be creditedto Dave Krantz, prexy of PRSMA

[Continued on page 6]


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RADIO SERVICE DEALER OCTOBER, 1949 5

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FIELD FINDINGS

[from page 4]

and the Program Committee, MessrsLau, Rincoe and Vogelsang who wereable to obtain as lecturers men whoare outstanding authorities in theirrespective fields, and whose subjects,in each and every case, were gearedright down to present day require-ments of technicians in the radio andTV fields. Here's the program :

Monday, Sept. 19th."Modern Servicing & Alignment"

by George Devine of G. E. Co."National Servicing Problems" by A. T.

Alexander, Service Committee of RMAand Service Manager of Motorola, Inc.

"'Scopes, How To Use Them," by CarlQuirk, Allen B. DuMont Labs.

"TV Alignment" by A. G. Petrascek,RCA -Victor.

"TV Servicing by Dynamic Demonstrator,"by John Meagher, RCA.

"TV Front Ends," by F. W. Edwards,Standard Coil Products Co.

"Fan Type Antenna Development"by Harold Harris, Channe'l Master Co.

"Servicemen's Organizations" by SandyCowan, Radio Service Dealer Magazine.

"Electronics-Your Fatty., In It," by JohnF. Rider, Manual Publisher

Tuesday, Sept. 20th."Electronic Antennae," by Caywood

Cooley, Philco"Multiple TV Reception," by Milton Shapp"Test Equipment," by Wm. Hensler,

Howard W. Sams Co."Indoor vs Outdoor Antennas" by I. Kamen,

RCA Com'l Sound Div.To a man, the several thousand

technicians, students and others whoare interested in radio and TV whowere fortunate enough to attend,agreed that PRSMA has set an ex-ample that other servicemen's associa-tions (and RMA's Town Meeting'sCommittees) might well follow.

There are now 81 TV stations onthe air, 34 more having CPs and try-ing to get on the air quickly, and 350other station applicants who are "fro-zen". Should, after the Sept. 26thFCC hearings, the proposed 42 new"upstairs" frequenices in UHF beopened, there could logically be 2200telestatioias instead of the 440 nowpossible with VHF alone. Recognizingthis situation RMA's Town MeetingCommittee Chairman, R.C. Sprague,opines that by 1956 there will be 24million TV sets in use, 80 million AMsets, and that 40 thousand AM tech-nicians and 50 thbusand TV tech-nicians will be needed to handle themaintenance problem.

Modern TV receivers contain ap-proximately 5 to 7 times as many



"I tell you, businesses aren't built onpromises. They're built on perform-ance-performance that brings cus-tomers back for more.

"And it takes good quality to guar-antee good performance!"Take Ken-Rad tubes. Why, they'vebeen the quality leader for years-backed by one of the country'sbiggest, finest companies with plentyof engineering know-how.

"Result is, Ken-Rad tubes havepaid me a steady dividend of in-creased business. For turnover andprofit, they have what it takes!"

RALPH L. CLARK, Foreman, MiniatureMounting Section, is one of the many ex-perts who carefully supervise the manufac-ture of Ken-Rad tubes. These men buildquality into the tubes at the very beginning;test out trouble at every stage of production.

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HOWARD L. BOLIN,,Omaha, Nebraska,with thousands of dealerslike him, sells the tubesthat sell fast and staysold-Ken-Rad tubes.

"Here at the plant we put Ken-Rad tubesthrough one test after another to provetheir quality is unsurpassed."The 'short' test, shown on the left, is giventubes before the characteristics test. It en-ables us to spot tubes that are not up toKen-Rad standards."Ken-Rad tubes also are tested fo.&.' noise,

microphonics, life, appearance, gas, airand hum."We don't guess. The Ken -Rod tubes we make and shiphave proved themselvesover and over again!"

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7

Sctsi

444:40:

I

The WR-39A and WR-59A combined with the WO -55A Oscilloscope in RCA's newWS -17A Rack, provide a modern, self-contained set-up for the efficient and profitablealignment of television receivers.

t / fairegto accurate television alignment

The RCA WR-59A Television Sweep Generator

The RCA WO -55A Oscilloscope

The RCA WR-39A Television Calibrator

Designed by RCA engineers at "tele-vision headquarters"-these com-panion units furnish all basic signalsnecessary for the rapid, accurate align-ment of television receivers. Flexibil-ity, dependability, and accuracy areoutstanding characteristics of theseinstruments.

For alignment, the WR-59A Televi-sion Sweep Generator and WR-39ATelevision Calibrator can be used withthe RCA WO -55A General PurposeOscilloscope matching unit-as illus-trated-or with any good oscilloscope.

The WR-59A Television Sweep Generatorcovers all television frequencies. Allranges develop 0.1 volt rms or more onfundamentals and can be quickly se-lected by means of a band -switch.Excellent shielding plus a piston at-tenuator allow the output to be re-

duced to the noise level. Unusuallyflat output is provided with amplitudevariation on all ranges of less than1 db. Phasing and retrace -blankingcontrols are incorporated.

The RCA WR-39A Television Calibratoris a variable -frequency oscillator, dual -crystal frequency standard, and het-erodyne detector with audio amplifierand speaker. The VFO puts markersof fundamental frequency and crystalaccuracy on TV -FM traces from 19 to110 Mc and 170 to 240 Mc. Dual -crystalstandard is used to calibrate VFO orother signal, generators with 250-kcand 0.25 -Mc check points from 250-kcto 240 Mc.

See your RCA Test Equipment Dis-tributor today for further technicaldetails or write RCA, Commercial En-gineering, Section 55JX,Harrison, N. J.

For test equipment you can trustalways keep in touch with your RCA Distributor

RADIO CORPORATION of AMERICATEST AND MEASURING EQUIPMENT HARRISON. N.J.

FIELD FINDINGS

[from page 6]

components and tubes as a conven-tional AM set. The breakdown poten-tial of TV compared to AM is al-most 10 to 1. Thus a million TV setsin use are comparable to 10 millionAM sets insofar as repair and replace-ments needs potential are concerned,and the radio technician who fails 'toget the intricate "know-how" requiredfor TV servicing is simply invitinghis own elimination from the fieldbecause the new -corners who havereally learned TV service techniquesare becoming more strongly en-trenched hourly. You can't say Ididn't warn you old-timers.

My June -July Tours

During the hot summer monthsyours truly was busily engaged inkeeping speaking engagementsthroughout upper Pennsylvania citieswhere I was the guest of the severalassociations. My technical lectures on"Video Detectors & Amplifiers" werewell received despite the mid -90 degreetemperatures. I lost ten pounds butthe fellows who heard me admittedthat they got some pointers aboutphases of TV that are not too well un-derstood. Incidently, business condi-tions in upper Pennsylvania are betterthan in many spots around the coun-try, and mainly because the type ofService Dealer situated in the QuakerState is above par. They function ina businesslike manner, dress and actlike professional men, command andreceive high living standard fees.

The Skimp Is Waning

The chaotic condtions due to price-cutting by TV dealers, price -reducingby '1V manufacturers, and confusioncaused by the questionable legality ofso-called TV service "policies" and theunknown position of FCC regardingUHF and color TV have all been dis-sipated and now the field has returnedto a semblance of normalcy. The pub-lic knows color TV is a long way offand that should it come, or shouldUHF bands be opened, they will notcause obsolescence of present-day TVmodels for they can be "converted" atmoderate cost. The only cause forworry, insofar as technicians are con-cerned, is the ever present threat thatUnions, or Guilds, or License billsmight find their way into this indus-try. The time is not yet ripe for con-sideration of any of these innovationswhich might restrict free enterprise.


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RADIO SERVICE -DEALER MAGAZINE342 Madison Ave., New York 17, N. Y.

Please enter I year subscription orders for the namesgiven below. Our remittance is enclosed.

NOTE: If you do not wish to fear this order blank out, just print ortype the information on a single sheet of paper, following the stylegiven. Each subscriber's occupation must be clearly described.

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TRADEFLASHES

A "press -time" digest of production,distribution Elk, merchandising activities

RCA Announces Insurance PlanOwners of television receivers in

New York State are assured replace-ment of parts and tubes, includingthe kinescope picture tube, under aplan announced Oct. 7 by the RCAService Company and approved bythe Insurance Department of NewYork State.

The plan provides for the replace-ment of parts and t*Ies during theone-year period of a Renewal ServiceContract under an insurance policyissued by Massachusetts Bonding andInsurance Company, it was disclosedby the RCA Service Company. Theinsurance plan may b` applied to allrenewal contracts purchased in NewYork State.

The plan has beef- developed as aprotection for RCA Victor televisionset owners after a recent ruling bythe New York State Attorney Gen-eral declared inclusion of provisionsfor replacement of parts-, as tubes ina renewal contract a violation of thestate's insurance laws. In seeking tomake provision for replacement ofparts and tubes during the term ofthe television owners renewal servicecontract and to comply with the rul-ing, the insurance plan was formu-lated.

"The insurance plan, serves twopurposes", A. E. Spottke, Vice Presi-dent of Massachusetts Bonding andInsurance Company stated. "It servesnot only to give added protection totelevision set owners purchasing re-newal service contracts, but also helpsthe entire television industry opera-ting in New York State in finding asolution to the problem previouslyfaced by television organizations de-siring to offer an important servicein a consumer's renewal service con-tract which would be in compliancewith the state's insurance laws. Theinsurance plan accomplishes this."

Color TV Years OffThe Radio Manufacturers Associa-

tion recently told the Federal Com-munications Commission that even ifthe Commission were to authorizecommercial color television after its

forthcoming television hearings it willtake manufacturers "several years" todevelop and distribute the necessaryequipment for public use.

Sylvania Launches TV LineSylvania executives were on hand

on September 7th at Sylvania Center,Bayside, Long Island, N. Y., whenthe company held a press preview ofthe new Sylvania television sets.Left to right are: Donovan H. Tyson,controller; Walter E. Poor, chairmanof the board; H. W. Zimmer, vice-

president of operations; G. R. Holden,vice-president and assistant to thepresident; R. H. Bishop, vice-presi-dent in charge of sales; J. S. Learoyd,secretary; Larry Bagg, sales manager,Colonial Radio Corp., wholly -ownedSylvania subsidiary which manufac-tures the Sylvania Television sets;H. R. Shaw, chief engineer, televisiondesign, Colonial Radio Corp.; JoeQuick, executive vice-president, Colo-nial Radio Corp., and Dr. ,R. M.Bowie, manager of the SylvaniaPhysics Laboratory.

Alliance Using Spot FilmsUsing television to sell their Alli-

ance Tenna-Rotor--a television an-tenna rotating device-the AllianceManufacturing Company is appearingwith a regularly scheduled series ofsix television sound films over mostof the major television stations.

The Alliance films made their firstappearance on the air in New Yorkover WNBT and in Cleveland overWEWS and WNBK, back in the early

[Continued on page 121


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A new Display, 14x17 inches, captioned "Which One is thePhony". It shows two greatly enlarged photos of stamps,one genuine, one a known counterfeit, with identifyingcharacteristics and means of recognizing the forgery. Over10,000,000 people in the U.S.A. are stamp collectors. Thisdisplay will be of interest to young and old, and willattract attention to your windows and, consequently, busi-ness to your shop. 2 displays will be issued each month,and you can get them FREE of CHARGE from your Jobber.

NOTE: Are you receiving your copyof "Successful Servicing?" It's Rider'sown publication of interest to everyServiceman. Write for it . . . it's FREE!

ANOTHER NOTE: The C -D Capacitor Manual for RadioServicing, 1948 edition No. 4, makes reference to only onesource of receiver schematics - Rider Manuals.

RADIO SERVICE DEALER OCTOBER, 1949 II

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Guesswork's gone . . . when youuse individually marked Ohmite"Little Devils." These tiny butrugged resistors are available instandard RMA values, 1/2, 1, and2 -watt sizes . . . 10 ohms to 22megohms. Tol. ± 10% and ± 5%.Values to 2.7 ohms available in1.watt size, ± 10% tol.

BROWN DEVIL RESISTORS

A favorite with servicemen, these de-pendable, wire -wound, vitreous -enameledresistors are easily mounted by theirtinned wire leads. Tol. ± 10%. In 5, 10,and 20 -watt sizes.

OHMITE MANUFACTURING CO.,

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Factory packed in each cabinet's 40 separ-ate compartments are 125 carefully selected"Little Devils" (tol. ± 10%) . . . in the 40values from 10 ohms to 10 megohmsmost fre-quently used by servicemen. It's no troubleto find the resistor you need . . . fast!

Molded of strong, lustrous plastic, andextremely compact-only 9° x 434" x 5%"-Ohmite cabinets protect your resistors, too,and help you check inventory at a glance.You'll want to order both assortments, today.

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TRADE FLASHES[from page 10]

part of June. At present more than22 television stations in most of themajor Metropolitan centers east of theMississippi have regular schedulesgoing well into the fall and into 1950on Alliance Tenna-Rotor.

R.C.A. Introduces New AntennaA new television antenna array,

engineered specifically for use infringe reception areas lying betweenstations occupying the same or ad-jacent channels, when the signals arebeen introduced by the RCA TubeDepartment. Called the RCA Rever-sible -Beam Television Antenna Array;it is designed to prevent the signalof one station from interfering withthe signal of a station lying in theopposite direction.

Air King Allocates TVR. D. Payne, Manager of Sales, Air

King Products Company, Inc., Brook-lyn 32, New York, Manufacturers ofRadio, Television and Wire Record-ers, announced that all television pro-duction is now on allocation. Thetremendous increase in Air Kingtelevision orders has literally swampedthe Sales Office.

G.E. Produces 81/2 Tube

First production of television pic-ture tubes at Electronics Park, Gen-eral Electric's TV production andengineering plant at Syracuse, N. Y.The tube being made in this pictureis the new 8% -inch metal electromag-

netic type, the first to be produced inthe industry, G. E. claims. It gives50 per cent more picture area thanthe seven-inch tube now used in low-priced receivers and costs no more tobuild. Larger size TV picture tubeswill be made at Syracuse later inthe year.

General Electric is spending overa million dollars to provide the most

[Continued on page 331I2


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KNOB MASTER FIXED SHAFTThis 3" long fixed shaft is standard on the QControl. 90% of all AM, FM and TV WI" knobscan be accommodated without alteration, exceptcutting to length. It is knurled, flatted and slotted,and ends spread easily for worn or oversize knobs.Shaft inserts are no longer needed.The Knob Master Fixed Shaft combines with com-pact 15/f6" design and VI" long bushing to providethe industry's most adaptable small control.

11 INTERCHANGEABLE FIXED SHAFTSNow it's easy to adapt standard controls to "spe-cials". Resilient Retainer Ring, an outstandingcontrol design advancement, permits ready adapt-ability to any of 11 special FIXED shafts in lessthan a minute-using only a knife or screwdriver.Shafts are FIXED and permanent! They willnot wobble.Interchangeable Fixed Shafts are sealed in cello-phane and individually packaged. Simple instruc-tions are included in each carton.

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14RADIO SERVICE DEALER OCTOBER, 1949

P.A. TECHNIQUES

3DA .Coming Etactimth

CONGRESSIONAL elections this fallmean extra business for P A or

Sound Service Men. Preparation bythe Wide -a -wake will be followed upby a greater Take. Don't be stymiedby a mere routine test of your equip-ment then lean back and await aphone call. To begin with you haveto go out after the business. Manypoliticians have friends in the game.Competition will be keen from allangles. So,-prepare yourself for lu-crative returns. It is the aim of thisarticle to be of aid in technical prepa-ration for those who do not alreadypossess a seasoned Know How.

There will be indoor and outdoorassignments presenting problemswidely diverse. There will be one nightstands and semi -permanent setups.To gain the most from the space limitsof this article, only practical P Aangles, heretofore uncovered in pre-vious issues of Radio Service Dealer,will be discussed. Much repetitioncan be avoided here yet the subjectthoroughly detailed if the reader willrevert back to his files of RSD forthe following:

PA Fundamentals & Com-plexities Oct. 1947

70 Volt LoudspeakerLine Jan. 1948

Bad Acoustics CuredElectrically July 1948

155 Loudspeakers VoltageFed Nov. 1948

In the electioneering jobs soon to behandled there will be problems of :Purchase of new equipment; modifica-tion or addition to present equipment;sound truck mechanical & electricaloverhaul; power supply available; rec-tifiers or converters needed; powerconsumption and distribution; gen-erators and fusing; local and tem-porary wiring; unusual requirementsto be met; musical fill-in facilities;testing and maintenance; best loca-tion for equipment; loudspeaker effi-ciency, distribution and coverage;wattage ratings and impedancematching; microphone placement and

by C. A. TUTHILL

We are holding over forment of, "Highpresent to our

next month the second install -Quality Analysis Series," in order toreaders this timely article on P. A.

TOMIC.

INPUTTRANSF.

RICI

LOW -Z INPUT

410

41110

411/0

RESULTS IN GRADUAL TAPER FROM 1500C.P.S. DOWNWARD TO 12 DB. AT 50 C.P.S.

Cl

600OHM

INPUT

RESULTS IN 3DB. LOSS AT 400 C.P.S.10 100 C.P.S.

VARIABLE EQUALIZER VALUES

INPUT RI CI

250OHMS

1000OHMS

0.5MFD.

30OHMS

120OHMS 4.0 MFD.

600 OHMLOAD FOR 600 OHM CIRCUIT

C1= .33 MFD.RI = 6000 OHMS

Fig. I-Two inexpensive equalizers for speech P.A.

cable runs; feedback and acoustics;smart equalization and many lessersubjects. All of these should be studiedand solved, in so far as possible, wellin advance of curtain time.

Spectrum Equipment

In the electioneering field the soundsystem operator does get one break.Excepting the rare requirement forhigh quality musical fill-ins, his sys-tem need only be capable of project-ing a high grade of intelligibilitythroughout the narrower spectrum re-quired for speech. This should savehim headaches and dollars as well asweight in portable equipment. Wherespeech alone is handled there is ab-solutely no need for reproduction ofthe lower lows. In fact unintelligibil-ity and acoustic feedback will resultunder high gain operation if the lowerend of the frequency spectrum is noteither rolled off or chopped throughsensible equalization of an otherwiseflat channel. Two simple inexpensive

equalizers, easily constructed for thispurpose, will, be found in Fig. 1. Inthe electioneering business we haveno demand for high quality audioprojection. More than ample spreadembraces the region between 250 cpsand 5000 cps. A cut-off somewhatabove 250 cps will not affect intelli-gibility, merely tend to thin out avoice basso in character. But, don'tforget, seldom will the electioneerproject any low tones vocally. Hisenthusiasm and emphasis will auto-matically carry his mean average ofdelivery up the scale. Research hasproved that there is considerable ofspeech energy present at 3000 cps forthe average orator. Therefore the topend of the sound system should be atleast maintained to 4000 cps or better.Another good argument is that listen-ing acuity in the upper register fallsoff with age. Your political audiencewill include many elderly voters.

It must be remembered that anamplifier qualifying between 250 and4000 cps is not in itself enough. Every


component within the system from themicrophone through the loudspeakershould be capable of a reasonably flatresponse through the speech spectrum.Some may argue that the maximumenergy of speech lies below 400 cps.That is true but, for understandibil-ity, frequencies from 400 cps down-ward are not as important as are thehigher frequencies. In reverberantrooms the lows will of necessity berolled off through equalization orthere will be no intelligibility what-soever, just gutteral gibberish. Intruly high powered exterior systems,where intelligibility is the only re-quirement, the sound spectrum maybe held between 400 and 4000 cps yetthe results will prove highly satisfac-tory.

For an extreme condition seldomencountered, except under such con-ditions as during battle aboard ship,it has been found that better resultsare obtained through either cuttingoff sharply at 500 cycles or throughengineering an emphasized character-istic having an upward slope of 6db per octave. In commercial practicethe latter method can be used to out -

shout a noisy mob in convention.

Power RequirementReference to the curve and table

of Fig. 2 will save much wordageherein. They are drawn up from wideexperience. The curve is based uponthe use of an exponential trumpettype horn of average efficiency hav-ing a 30 degree angle of coverage. Itshows the amplifier power needed perdistance for clear audition. This curveapplies where the background noiselevel is reasonable. On exterior worksimilar conditions may obtain. When,however, there is a disturbing noiselevel such as from constant nearbyheavy traffic, it will be found best toemploy a sound system whose capacityis sufficient to project a single fre-quency at a level 10 db higher thanthat of the noise through which speechis to be understood. This margin willallow for losses due to masking causedby the noise. Speech is used for ref-erence since exterior music is in thiscase incidental and indeed not be soloud except when used as an attention -

getter.The total power capacity of a driv-

ing amplifier in a sound system isdetermined by the sum of the powersrequired by all loudspeakers driven.The amplifier output must be equalto or greater than the sum of the watt-age for all horns used. It is well touse two amplifiers where several hornsare required. Distribution can be so

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11- ' ril hi-- I I I

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60RELATIVE AMPLIFIER POWER CAPACITY - MAX. SINGLE FREQUENCY OUTPUT

RATING IN DECIBELS ABOVE 0.001 WATT

Fig. 2-Amplifier power needed for various distances.

staggered that should one amplifierfail, the other would still radiate afair coverage during repairs to thefaulty unit. Non-linear distortion pos-sibly as great as 10% may be toleratedin channels set up strictly for elec-tioneering purpose whereas in highquality channels this factor shouldbe held to limits of 1% or 2% harmo-nic distortion. Half of the battle liesin the avoidance of microphone blast-ing. Wire guards similar to a dogsmuzzle can be fashiOned and clampedto microphones to keep orators at areasonable distance when this ob-noxion becomes out of hand.

When loudspeakers loads are re-duced, and several of the paralleledhorns simultaneously removed fromthe line, it is well to reduce the driv-ing gain so as to minimize non-lineardistortion. Properly handled this willnot reduce the normal output of thehorns still in use. Overload checksshould be made when the system isworking at maximum capacity so asto hold distortion to a minimum.

The maximum gain required of asound system, for a delivery whichshould over -ride ambient noise byabout 10 db, is determined by theweakest pickup device. This is oftenthe phono-pickup and attendant equal-

izer for vertically cut records. Thereshould be sufficient gain to peak yourlevels from such a device to the max-imum single frequency power outputrequired of the system. To be surethat an adequate source of supply ofpower is available, total power require-ments of the total system should bepredetermined prior to installation.Then a survey of the job -site will de-termine whether adequate power isavailable or whether boosting devicesare necessary.

Unusual Requirement

Very often during election assign-ments, even though your contract maycall for a semi-permenant setup, spe-cial features present themselves whichmust be taken in stride. For example:-

a rally within a hall may be recessedat 5 p.m. or 6 p.m.; the hall may berapidly converted to serve a banquet'at 8 p.m.; the following morning therally may be in session again. Thealert sound operator will have hisplans laid to handily cope with theserapid changes. His microphone andloudspeaker cable runs should neverbe so interlaced with structure orequipment that they cannot be quick-ly unshipped, coiled, and made readyfor a quick roll back into their orig-


Table L

Wire Size

A.W.G. (B&S)

Load Impedance in Ohms

2 4 6 8 10 16 , 32 50

No. 10 150' 300' 450' 600' 750' 1200' 2400' 3750

12 95' 190' 285' 380' 475' 760' 1520' 2360'

14 60' 120' 180' 240' 300' 475' 950' 1500'

16 38' 75' 113' 150' 190' 300' 600' 950'

18 23' 47' 70' 95' 118' 190' 380' 590'

20 15' 30' 45' 60' 75' 118' 236' 375'

22 9' 18' 28' 37' 47' 75' 150' 230'

Maximum length of line for I5% power loss in range of common voice coil impedances. Length fromfrom amplifier to load.

(Courtesy Jensen Radio Mfg. Co.)

inal displacement. Plugs, jacks andconnector blocks, guarded with cableclamps, are big time savers. Directtie-ins take too long to disconnectand reconnect.

On exterior assignments a dual fa-cility (duplicate system) may in theend save money and reputation. If adignitary is serviced making a speechin the suburbs following which he isrushed under police escort to presentanother speech in the city, it payswell to have a second sound channelready, tested and awaiting, his arrival.No attempt should be made to coverthe two assignments with one mobiletruck unless there is a luncheon totake place between the two pickups.See the November 1948 issue of RadioService Dealer (page 40). It detailshow 155 low level loudspeakers wereremoved following a 5.30 p.m. sessionclearing decks for an 8 p.m. banquet.All 155 units were serving the session -the following day at 9 a.m.

Indoor vs. OutdoorWith the same equipment there is a

great difference between the handlingof interior or exterior pickup and re -enforcement of sound. In free spaceoutdoors sound waves move directlyfrom their source to the listener, thereseldom is a reverberation factor al-ways present indoors. Since the hu-man ear is a pressure actuated device,it is necessary generally to projectsound at a greater level outdoors fora given result. Sound overprojectedhowever will, when reflected fromnearby structures, cause Bareback orechoes sometimes unbearable in con-tent to an audience near them. Achange of horn tilt or angle or lowerpowered projection will overcome suchconditions.

Many benefits are derived from theuse of directional horns on long -throwexteriors. Cellular horns will readilycontrol directional projection to pre-determined angles vertically and hor-izontally. Wind and ambient back-ground noises are factors to be rec-koned with here. The further off thebeam the greater the loss of highs.This again points out the fact origi-nally established that the tap end ofthe sound spectrum should be retainedto at least 4000 cps. For exterior workit is well to retain even higher fre-quencies because of their dissipationinto free space. Intelligibility andcrispness of speech falls off as theazimuth from dead center horn axisincreases. This is only true above 200cps but pertains to the most usablesector of the response range.

The average re-entrant horn, in-versely folded for length and weatherprotection, is highly satisfactory forless directional radiation to an im-mediate audience often serviced bysound trucks. But when distant throwsof sound must be beamed deeply intoa remote audience directional hornsare definitely required. Tangible re-search has found that a horn's direc-tional pattern is determined by theform of sound emerging from thehorn mouth together with the Dimmerin which the amplitude and phase ofpressure vary over the wave front. Itis also known that intensity falls offinversely as the square of the dis-tance. If distance is doubled, responseis lowered 6 db whereas when dis-tance of projection is halved, responseis increased 6 db.

For a given power consumed ex-ponential cellular horns are the sim-plest answer to directional projection.From them a gain in pressure 'on the

directional axis is derived as com-pared to the broad spread from non -directional radiators. Configurationof horn mouth is a determining factor.The lateral and vertical spread can beclearly defined to requirement by thenumber of horn cells clustered togeth-er vertically and laterally. Such treat-ment is used behind screens in thea-ters so to adequately serve balconiesalong with orchestra seats. It is quitepossible to radiate a narrow beamlaterally and a wide beam verticallyif the horn cluster mouth is madeasymmetrical so that its width isslight and its height is large in termsof wavelength. Manufacturers willsupply actual facts on coverage fortheir various products. Such datashould be studied before horns arepurchased or installed indoors or out.

Loudspeaker EfficiencyLoad carrying capacity and effici-

ency are of great concern to the soundsystem operator. An efficient horn orhorns can save much in initial driv-ing amplifier cost where it hurts themost,. Load carrying capacity meansthe maximum power which can orshould be applied to a loudspeakerdriving unit. This power is limitedby heating, mechanical or structurallimitations, driving amplifier limita-tions, and by non-linear distortioncaused by just too much diaphramamplitude, directly the result of over-driving a unit.

Efficiency in a loudspeaker is notmerely a question of load carryingcapacity. We are concerned aboutthe loudness of sound obtainable notonly at one point but throughout itsspread of coverage. The financial im-portance to the sound operator is justthis,-a high powered hence highly



Front view of Kay Megaliner

WIDE band television sweepgenerators of the Megasweep

variety do not ordinarily containmarkers. Separate outside sourcesare used to generate these precisemarker frequencies which are usedto point out exact frequencies inthe alignment of television video i-fand sound amplifiers. While the sweepgenerator is able to supply the widefrequency excursion needed for visualalignment, some other source is neces-sary to establish particular exactpoints along the visual alignment os-cilloscope trace. These markers are oftwo general varieties; the separatesignal or pip, and the absorption type.

The pip marker appears as a sharppulse along the base line and as itsfrequency is changed, the pip moves tothe right or left along the oscilloscopetrace. The absorption type markerconsists of a resonant circuit whichabsorbs energy at the exact frequencyto be measured and appears as a breakin the response curve displayed onthe oscilloscope. There are televisionsweep generators on the market whichuse either or both types of markersbuilt in to the generator itself. Withthe Megasweep system however, a sep-arate external marker is used becauseof the wide band coverage of the orig-inal Megasweep generator.

This marker generator is known asthe Megaligner and it supercedes theMegamarker which is produced by thesame company. The Megaligner is acalibrated variable frequency markerpip generator. Its frequency range isfrom 19 to 49 mc in two bands. Thefirst band is 19 to 30 mc and the sec-ond band is from 30 to 49 mc. Theoutput may be either a marker pip, a

KAYMEGALI N ER

by ALLEN LYTEL

Author of TV PictureProjection & Enlargement

The Megaliner is a calibrated frequency marker pip gen-erator for use with the Megasweep described in la st month'sMD. The marker pip may be fed directly to the oscillos-cope used in the test without feeding it to the circuit.

liES811CABLE

LOW CAPACITY SHIELDED LEAD OR TWISTED PAIR_

WS ALI CHERPIP OUTPUT

SWEEPING OSC, RG SS UINPUT OUTPUT CASLIE

r ------ -1 1TN/ RECEIVER I

t I I

soi I

,n. 1

I

i 1

4- --rn1

t

T-1...UO3"wiRTER 1

a TO %

I I1 StveF7c7u7r1 SINELA

I

I I MEGA -SWEEP LL -1I . OSCILLOSCOPE

tI If i 1,

Ii I

LOW OMR ITo

ioarco- L__ iI Y X ---1IDETECTCM_ -7-- --7\ )AXIS NM 4-1

1 1 kW t-i I j 11- --11- 1i I1L -- 1 I 1._

71.10E

SH IELDED LEADFig. 2-Connections between Megaliner, Megasweep oscilloscope and receiver.

Leads should be as short as possible.

variable frequency C W signal sourceor a 4.5 mc crystal oscillator.

Megaliner Features

The pip output provides approxi-mately 10 volts peak to peak and asa signal generator, the output is 4000microvolts across 50 ohms. When usedas a crystal oscillator operating at 4.5mc, the voltage output is 0.3 maximumacross 50 ohms. One outstanding fea-ture of the Megaligner is its provi-sion for the marker pip to be fed di-rectly to the oscilloscope used in thetest procedure. The marker is not fedthrough the circuit under test, hence

it cannot overload the video amplifier.The serviceman who has had experi-ence with conventional markers, isundoubtedly acquainted with the factthat some types cause an overloadsince they must be fed through thei-f amplifier. By means of the Meg-aligner the marker is by-passedaround the circuit and fed directlyinto the oscilloscope Y axis amplifier.

When being used with visual align-ment, a variable frequency pip is pro-vided which remains visible at anypoint along the trace including the.traps and the discriminator character-istic. The variable frequency OW sig-nal which is provided, can be used in


dignment procedures where theVTVM is used as the indicating de -rice. A 4.5 me crystal controled signala very important in the alignment)f intercarrier sound television re-

.;elvers.

Figure 1 is the schematic of theIegaliner. A selfcontained power sup -Ay using a 5Y3 provides a 300 volt)ositive output. The 3 amp. fuse, F../s replaceable from the front panel.)ther tubes used are the 6AG5 RadioFrequency Buffer Amplifier, the

TZ-5 Variable Frequency Oscillatormd Detector, the 6J6 Audio Frequen-ur Amplifier and the 6AG5 Crystal)scillator.

:ircuit Description

A brief circuit description is nec-issary to understand the function of

Megaligner controls. S-/ is theSower Off -On switch; S-5 is a B sup -)1y switch which provides high voltage!or either the variable frequency os-yillator or the crystal oscillator. Withhis Single Pole Double Throwswitch, in the Crystal position, B pluss supplied to the crystal oscillator.this tube, V-.4, oscillates at a fre-raency of 4.5 megacycles controlled)y the crystal X-1. With this switchn the Variable Oscillator Position,

the Variable Frequency OscillatorTube operates at a frequency deter-mined by the band switch and reso-nant circuit tuning. The frequency ofthis oscillator V-2 is the frequency atwhich the dial calibration is set.

The band switch for the variableoscillator is a Double Pole DoubleThrow switch arranged to utilizeeither of two tuned circuits. L-1 and0-20 are used on the low band andL-2 and C-24 are used on the highband. The tuned circuit which is chos-en by the Band Selector Switch alsooperates as the plate load impedanceof V-/. This plate load is shunt con-nected to the plate of the Radio Fre-quency Amplifier by the couplingcapacitor C-5. In order to isolate thevariable oscillator from the circuitunder test, the radio frequency am-plifier is placed between the variablefrequency oscillator and the input.

To provide a pip, the sweeping os-cillator signal from the Megasweep isfed through the buffer amplifier andto the variable frequency oscillatorwhich also functions as a detector.The tank circuit of the variable fre-quency oscillator is connected betweenthe control grid and cathode, and twodifferent signals are fed to the con-trol grid simultaneously. One of these

signals is the sweeping oscillator sig-nal from the Megasweep and the otheris the signal frequency of the variableoscillator itself. A pip is formed fromthe resultant beat note which is thedifference between these two signals.This pip or beat note is passed throughthe tuned circuit network to the gridof the 6J6 audio frequency amplifier.This tube, V-3, is resistance coupledas an amplifier and provides a signaloutput between its plate at pin 1 andground. P-2 is a variable control usedto adjust the relative level of thePip Output.

It is important to see that no actualpip or marker is generated in theMegaligner itself. The external sweep-ing signal from the Megasweep isnecessary in order to produce a pipoutput. The variable frequency oscil-lator V-2 is tuned to the exact fre-quency of the output desired. Sincethe desired pip output must be some-where in the frequency range whichis being swept by the master genera-tor, at some point the Megasweep out-put and the variable oscillator V-2will be at the same frequency. Justbefore this frequency is reached, abeat note is obtained which is the dif-


SWEEPINGOSCILLATOR

INPUT OUTPUT R4

APILOTLIGHT

RI

Z3

C4

CZ4

C22

XTAL05C

C23

R20

300

A rAMR

V34a

CIS

4.16 _L

E13

PC

CIL

El7

MEGALIGNEKSCHEMATIC

FIG. I

KAY acciric co PINE 1Woorm.J.

Fig. I. Circuit Diagram of Kay Megaliner

RADIO SERVICE DEALER OCTOBER, 1949 1?

TV QUIZ NO. 5by DAVID GNESSIN

BEFORE ANSWERING THE QUESTIONS - READ THESE RULES:

This quiz, based upon information made available bycourtesy of the Howard W. Sams Photof act TelevisionCourse will prove of value to all radiomen interested inreviewing TELEVISION. For those who possess the' Samscourse a reference to the page involved is given in paren-thesis after each question number. Readers should write

out the answers, cony the diagrams for practice, and circlecorrect answer if multiple choice is given.

After quiz is completed, compare with correct answersgiven on page 31 of this issue. Another TV quiz is nowbeing prepared for early release.

1. (p 13) Note Fig. 1. Under the"direction of electrons = direction ofcurrent" theory. the left hand rule de-termines the direction of magneticlines of force created by flow of elec-trons along a conductor. In the dia-gram the circular magnetic lines offorce are shown, but their direction

DIRECTIONOF

ELECTRONCURRENT

Fig. 2. Magnetic field influencingstream

arrow is missing. Copy the diagram,inserting arrows for direction.

2. (p 13) What changes would youmake in the drawing of Fig. 1 if thesolid wire conductor were replacedwith an electron beam operating in avacuum? Re -draw Fig. 1 showing thisnew condition.

3 (p 13) Consider Fig. 2. This isthe same as Fig. 1, except that ahorseshoe magnet has, been placedin such fashion that its end poles setup vertical magnetic lines of force asshown. How does this new field affectthe electron beam? Would it movethe beam itself, or only the beam'smagnetic field? Whatever it doesmove-which direction does it moveit:

Fig. I. Direction of electron

(a) Up(b) Down(c) Left(d) Right(e) None of the directions des-

scribed above4. (p 13) Note Fig. 3. The horse-

shoe magnetic field is no longer atright angles to the electron stream.The exact angle is not given, since

Fig. 3. Field at angle to electronstream

except for one angle other than theright angle, the effect on the electronstream will be similar to that shown inFig. 3. Discuss the effect of the horse-shoe magnetic field upon the electronbeam as shown in Fig. 3.

5. (p 13) In question 4 it was not-ed that except for 90°and an angulardifference similar to that of Fig. 3,

stream through a conductor

there was one angle in which themagnetic interaction was radicallydifferent.

(a) What is this one specialangle ?

(b) Discuss the magnetic inter-action between e le ctr onbeam and deflecting voltageat this special angle.

6. (p 14) In magnetic focusinga focus coil is placed about the neckof the C -R tube at the proper pointfor operation. (See Fig. 4.) The prop-er placement point is indicated by:

(a) A silver metallic band aroundthe neck of the tube installedduring manufacture, placedby instrument check. This


FOCUS COIL --

ACCELERATINGANODE -

Ei

CATHODE

Fig. 4. Position of focus coil on CRT

20 RADIO SERVICE DEALER., OCTOBER, 1949

Sivwking

PHOTO -ELECTRICequiPount

IGHT-operated devices are find-ing increasingly wide application

in industrial plants for counting,sorting and grading a wide variety ofarticles, mass -gauging of machinedproducts, etc.; in offices for elevatorcontrol and automatic operation ofdoors and drinking fountains; andeven in homes, for automatic controlof garage doors and lighting control.With this in mind, the servicemanwill naturally make an effort to cap-ture some of the business availablethrough maintenance and repair ofsuch equipment.

Servicing photoelectric equipmentis not at all difficult, and the circuitsused are less complicated than thosefound in even the smaller radio re-ceivers. There are, however, consider-able differences in the basic princi-ples, and we shall, therefore, discussthese principles briefly before pro-ceeding into a discussion of the actualservice techniques employed.

Basic Principles of PhototubeEquipment

A phototube consists of two elec-trodes-cathode and anode (or plate).The cathode is generally a half -cy-linder of metal which has been coatedwith a substance which emits electronswhen subjected to light. Some of thelight-sensitive materials used are theoxides of caesium, potassium andrubidium. The composition of thematerial used determines the sensitiv-ity of the tube to various light colorsor frequencies.

The anode or plate often consistsof a vertical wire or rod located inthe center of the semi -cylindrical ca-thode. The electrodes are placed insidea glass envelope which is either ex-hausted to a high degree and then

by WILLIAM R. WELLMAN

PART I

Beginning a two part article on the theory, applicat-ions, and servicing of photo -electric equipment. Thisbranch of electronics is easily mastered by the service-man, and can result in a substantial source of income_

PHOTOTUBE AMPLIFIERTUBE

Mla50012. 2KW.W. W. W. POT.

117 V.A.C.

RELAY

TOLOCAL

CIRCUIT

Fig. I. Reverse type of phototube relay circuit

sealed (vacuum -type phototube) orinto which a small quantity of gasis injected after pumping (gas -typephototube). The vacuum type is lesssensitive, but is more stable in oper-ation than the gas type. The increasedsensitivity of the gas type is due toionization of the gas with consequentincrease in electron flow. Ordinaryphototubes have a conventional glassenvelope, but those types which aredesigned to respond to ultra -violetlight may use specially treated glassor may have a thin, indrawn windowto permit passage of the light rays.

In operation, the tube is positionedso that light strikes the inner, con-cave surface of the cathode. Whenthis occurs, the cathode emits elec-trons and if the plate is then made

positive a small current will flow fromcathode to anode. The current willdepend upon the intensity of the light,the voltage applied to the plate, andthe type of tube (whether it is a high -vacuum or gas type). In any casethe current is small, generally beingmeasured in microamperes.

Since the output of a phototube issmall it must be amplified to be ofvalue in most applications. Very oftena single stage amplifier will serve,any of the beam power or pentodeoutput tubes being suitable. Whena two -stage amplifier is required.twin triodes such as the 6N7 or 6SN7are frequently used. In some equip-ment, the final tube is a thyratron.This is because such tubes will passa heavy plate current; also, because


Fig. 2. Reverse type phototubecurrent

in some applications a "lock -in" typeof device is wanted. This means thatonce the unit has been set into oper-ation it will continue to operate untilreset manually.

For our purposes it will be suffi-cient to divide phototube amplifiersunder two classifications. In the firstcategory we consider amplifiers fromthe viewpoint of the type of B supplyused; that is, whether the current insuch supply is a.c. or d.c. A largemajority of the equipment manu-factured is operated from an a -c sup-ply, but there are a few special casesin which -d.c. is essential. Amongthese are high-speed photoelectric re-lays which will not operate successful-ly from an a -c supply.

The second classification takesinto account the method of connect-ing the phototube with regard to thedirection of current flow and its ef-fect upon the plate current of theamplifier tube. An inspection of Fig.1 will clear this point up for you.In this diagram we see what is oftenreferred to as a reverse type photo -tube relay. The term relay is usedloosely here and in industry to re-fer to the entire unit consisting ofphototube, amplifier and the electro-magnetic relay, rather than to therelay itself. The action of the deviceis as follows: as long as the phototubeis illuminated the amplifier grid volt-age is relatively high and the ampli-fier plate current correspondinglylow. The relay therefore is not en-ergized and the contacts which con-trol the local or external circuit remainopen. Once the light is reduced or cutoff, the grid voltage is reduced, theplate current rises and the relay isenergized, closing the contacts.

Figure 2 shows the path of the pho-totube current upon which the oper-ation of -the circuit depends. The pho-totube current (as in any other tube),flows from cathode to plate as shownby the arrows, and as a result mustflow in a downward direction through

the grid resistor, R. We are aware thatelectrons always flow from minus toplus; consequently the top end ofthe resistor becomes negative and thelower end positive. This places a com-paratively high bias on the amplifiertube and keeps its plate current at aminimum. If light is entirely cut offfrom the phototuhe, no current flowsthrough R and its upper end is there-fore less negative. This makes the gridof the amplifier tube also less negativethereby increasing its plate current.

Before leaving the reverse circuit,your attention is directed again toFig. 1. In the previous paragraph, thestatement was made that cutting offlight to the phototube made the am-plifier grid less negative. It is im-portant to note that under this con-dition there will still be a negativebias on the grid; this is suppliedthrough the voltage divider consistingof Ri and R2. R2 is adjustable, andvarying the setting of this potentio-meter changes the sensitivity of theunit. Another important point is thatthe unit is operated from the a -c sup-ply line; this means that it will beable to function only on alternatehalf -cycles of supply line voltage, orwhen the plate is positive. This doesnot effect the usefulness of the de-vice, except in applications where itis required to operate in a period oftime shorter than. 1/120 second (as-suming a 60 -cycle supply. In suchcases a rectifier power supply wouldbe used. This type of relay would beuseful in many applications) an ex-ample being the automatic controlof drinking fountains. Normally, therelay which controls the water sup-ply valve is held inoperative by thelight beam focused on the phototube.When the user approaches the foun-tain, his or her body interrupts thelight, allowing the relay to close andturning on the water.

The forward hype of unit operatesin a manner just the opposite fromthat of the reverse type discussedabove. The difference lies in themethod of connecting the phototubeelectrodes so that the phototube cur-rent, as illustrated by the arrows inFig. 3, flows in an upward directionthrough R. Then, with the phototubedarkened, the grid bias applied to theamplifier tube reduces the plate cur-rent to the point where the relay can-not operate. When the phototube isilluminated, current flows as shown,making the grid of the amplifier lessnegative, which increases the platecurrent and causes the relay to close.Such a device would be used to auto-matically garage doors which are

actuated by the headlight beams ofa car.Installing and Adjusting Equipment

Photoelectric equipment intendedfor indoor use consists of at least two,possibly three, distinct units. Thelight source unit comprises the lamp,lamp housing and usually a lens. Insome cases the phototube will be lo-cated within the amplifier housing,but in a few devices a separate hous-ing is used for this tube. 'Where thisis done, a shielded cable is frequentlyused between phototube and amplifier,especially if the distance between thetwo is considerable.

When setting up the equipment,the manufacturer's instructions re-garding the allowable distance be-tween the light source and the photo -tube must be rigidly observed. Mountthe lamp housing in the position itwill occupy during normal usage. Ifthe light source is equipped withmeans for focusing or concentratingthe light, this detail is to be taken careof next. Place a piece of white card-board or similar material at the exactdistance from the light source thatthe phototube is to be. Turn on thelamp and adjust the focus until theimage on the cardboard screen is asbright and sharp as is possible to ob-tain. In some cases the focusing is ac-complished by sliding the lens tube inor out in the housing. In some modelsthis adjustment may be obtained byrotating the lens tube.

The next step is the adjustment ofthe unit for desired sensitivity. Thisprocedure will depend upon whetherthe unit is of the forward or the re-verse type. Furthermore, the arrange-ment of the sensitivity control differssomewhat in units produced by va-rious manufacturers. In the examplesused in our discussion in Section 1of this article, the sensitivity controlconsisted of a wire wound potentio-meter which was used to vary the ca-thode voltage of the amplifier tube.Another variation of this system is


Fig. 3. Forward type phototubecurrent


by WALTER H. BUCHSBAUMDevelopment Engineer Techmaster Products Co.

Fig. I. Completed view of receiver converted to 16 inch tube

A relatively simple kit for converting 10 inch TV receivers for use w ith the new16 inch tube is described in this article. This opens up a new field of revenue.

ALMOST 75% of all the televi-sion receivers sold in 1947 and'48 used a 10" picture tube.

Since the advent of the 16" tube andthe new large screen sets, many cus-tomers feel that they are losing outin the enjoyment of their televisionreceivers by not having a screen aslarge as the new models. There is agreat clamor for some way to adapttheir receivers for larger pictureswithout going through too great anexpense. In many cases, the audiencein the home has been increased be-cause better programs are now avail-able and more people in each familyhave become television fans. But themain reason for the demand forlarger pictures is the added comfortin viewing and the greater detailpossible. Whatever the reason, it is

Fig. 2. High voltage assembly

up to the servicemen to satisfy thisdemand and the easiest, most profit-able way of doing it, is by convertingthe receiver to a 16" tube 'as shownin this article.

A good way to get conversion jobsis to advertise for them. Many deal-ers send descriptive literature on con-versions to all their previous costum-ers having a 10" or 12" receiver. Localnewspaper advertising offering con-versions to a 16" picture tube alsoare very helpful. And finally, everyservice call concerning a small screenreceiver is an opportunity to interestthe customer in a conversion job.Occasionally, a dealer may find itprofitable to convert old receiverspreviously accepted as trade-ins foradaptation in custom installations.Whatever the individual circum-stances are, every serviceman will findthat the conversion business not onlybrings in additional revenue, but alsohelps expand the volume of his busi-ness and create more and better satis-fied customers.

Items NeededIn converting a standard 10"

receiver for use with the new 16AP4,two different approaches are possible.Using a standard high voltage powersupply, it will be found that thebrilliance and sweep width are notquite as good as they were on the10" tube. Most new 16" receivers are

designed to operate on 12 to 15 NVsecond anode voltage. To achievethis, a voltage doubler is used andcertain changes are made in the hori-zontal fly -back circuit.

With these changes, it is possibleto achieve full sweep from edge toedge and brilliance equal to or betterthan anything found with 10" sets.The main items needed for such aconversion are, of course, the 16AP4,a special high voltage fly -back trans-former, additional rectifier, and as-sociated components. The total costof the components and parts used inthe conversion kit described below, isfar less than the price difference bet-ween a 10" and a new 16" receiver.The Tech -Master 16" Conversion Kit

The photograph in Fig. 1 showsa completed conversion. While thekit was especially designed for useon RCA 630 type chassis, it can easilybe adapted to convert almost everyset for use with a 16" picture tube.Two separate types of changes arerequired and will now be taken upin detail.

Mechanical changes include the re-moval of brackets holding the smallscreen tube and substitution of thespecial adjustable brackets shown inFig. 1. In addition, the followingparts must be exchanged:

1. Horizontal output transformer.2. Focus coil.


3. High Voltage assembly.4. Width control coil.5. Horizontal peaking control.The high voltage assembly used for

the doubler circuit is shown in Fig. 2.Note the two high voltage rectifiers,3 high voltage condensers, a specialtwo megohm, bleeder resistor and thetype 211T5 horizontal output trans-former. To mount the high voltagerectifiers and condensers a specialbakelite assembly is supplied as shownin Fig. 2.

The electrical changes are foundin the schematic diagrams of Fig. 3The 250,000 ohm horizontal peakingcontrol is substituted for the previous-ly used 20,000 ohm potentiometer,and put in series with R1 and R4 asshown. No changes are made in thevertical output except that R17 isconnected to the horizontal linearitycontrol.

The other major changes are madein the high voltage section. The volt-age doubler circuit is conventional,except for the use of a 2 megohmbleeder resistor. This resistor caneither be a special 2 megohm 10,000volt type as shown in Fig. 2 or elsecan be made up of four, 470,000 ohm,1 watt resistors in series. In the lat-ter case, the connection betweenresistors solderedjoint. All connections in the highvoltage section must be made so thatno sharp points are left, otherwisecorona or arcing may appear. Beforefinally mounting the high voltageassembly, be sure that all parts areclean and free from dirt, grime, orfinger prints, since this might, intime, cause corona trouble.

When adjusting the picture on the16" tube, after the conversion has beencompleted, a number of precautionsshould be observed. It is advisible touse a plastic shield and mountingring for the 16AP4 which can beobtained together with the tube. Thisplastic shield is very good protectionagainst high voltage shock caused bycoming too close to the metal portionsof the 16AP4 which are at the highpotential.

In many cases, it will be necessaryto lengthen some of the leads to thepicture tubes, and in so doing, 15,000volt test insulated wire should beused for the second anode lead. If aplastic shield is used, this lead goesto the clip provided on it; otherwiseit is connected to the metal rim ofthe 16AP4.

AdjustmentsTo obtain proper sweep width,

brightness and linearity, adjust thehorizontal peaking control first. It

- 100RI

1/2 6SN7vineHORIZ.' ,DISCH.

R2

6BG6HORIZ.

OUTPUT

R3 R4C1

R6

C2

3

6K6 GTV122VERT.

OUTPUT

T107 -100VERT.

OUTPUT

R7

R9

T1

azaa

1B3H.V.

RECT.

R10 R12

C8

R15

R14

R13

1B3H.V.

RECT.

a R11 C7

5V4G±

L

C5

-100

L1

L2

V128

WIDTH CONTROL

HOW. LINEARiT

C6

-100

-> R1 100K ohms, 1/2 watt-> R3 220K ohms, 1/2 watt-> R4 22K ohms, 1/2 watt-> R5 330K ohms, 1/2 watt-> R6 100 ohms, 1/2 watt-> R7 100 ohms, 1/2 watt

R8 100 ohms, 2 watt-+ R9 14,500 ohms, 5 watt WW or

(30,000 ohms, 2 watt) in par -(27,000 ohms, 2 watt) allel

R2.260,000 ohms Carbon ControlHorizontal Peaking Control*Used in place of 20K control

-> R10, R11 3.3 ohms, 1/2 watt---> R12, R13-> R14, R15 470K ohms, 1 watt

R16 1 Megohm, 1 watt

R17 10K ohms, 1 watt-> Li 1R4 Width Control

L2 1R3 Horiz. Linearity Control-> T1 **11T5 Horiz. Deflection Out-

put & High Voltage Transformer**Used in place of 11T1 trans-

former-> C1 .01 mfd, 600 V

C2 680 mmf, 1000 V MicaC3 0.1 mfd, 400 VC4 .05 mfd, 600 VC5 .035 mfd, 1000 VC6 .05 mfd, 1000 VC7 500 mmf, 10,000 V

--> 08 500 mmf, 10,000 V-> C9 500 mmf, 15,000 V

010 10 mfd, 450 V

Fig. 3. (*) Wiring indicated thus goes to same points as in original 630-1KParts indicated thus are additions to the original 630-TK circuit.

will be noted that this control goesthrough a point of optimum widthand linearity. It should be left there.To compensate for any non -linearitystill present, adjust the horizontallinearity control. If insufficient sweepwidth is encountered which cannotbe adjusted by the width control coil,several different methods are avail-able. Disconnect the width controlcoil entirely. If that does not work,reconnect it and shunt it with a .01mfd condenser. As a last measure toincrease the sweep, connect a .003 mfdcondenser from the cathode of the 5V4damper tube to ground. The newfocusing coil type (2D2) suppliedwith the kit is capable of providinggood focus over the entire face of the16AP4. This tube also requires anion trap as used with the 10BP4 andthe 12LP4.

When converting a set which didnot previously use an ion trap, it willbe necessary to purchase this partseparately. For simplicity, it is re-commended that a permanent magnettype ion trap or beam bender be used.

Conclusion

To many TV owners it will bemore economical to convert a smallscreen receiver rather than trade itin and buy a new 16" model. Thisis especially true in the case of asensitive and well -aligned set, suchas the 630, which in most cases hasgiven very satisfactory service. Intel-ligent salesmanship and honest, pro-fessionally done conversion jobs oftenconstitute a real improvement in theservice business from the point ofview of the serviceman as well as thesatisfied customer.


Detrola Model 611-AMost unusual feature of this instru-

ment is the performance on shortwave stations in the band between 5.8and 18.3 mc. The use of dry -batterytubes at such frequencies demands theuse of special techniques. The set isdesigned for use where power linesupply is not available. Five tubes areemployed in a super -heterodyne cir-cuit. Two bands are covered; con-ventional broadcast and one shortwave range.

The set is designed for use with anexternal antenna feeding the 1N5tuned r -f stage. This is followed by a1R5 pentagrid converter, with boththe signal and oscillator circuits tuned.Of particular interest is the use ofneutralization in the circuits connect-ed with this tube. The partial sche-matic can be referred to for details.Coils for only one band are shown.

Operation of the stage is as fol-lows: The #1 grid is the oscillatorgrid. It has a 150 ohm resistor inseries to suppress any spurious gen-eration. The 100K resistor returns tonegative filament and serves as gridleak. A 47 Aufd. capacitor couplesthe grid to the tuned circuit, coilsbeing switched for range change. Thetrimmer across the grid coil has aseries resistor also. Feedback is pro-vided by a plate coil and the plate(actually #2 grid) is shunt fed viaa 10K resistor. The .005 Afd capacitorcompletes the feedback circuit.

The signal is coupled to the #3grid directly from the range switchand tuning condenser. Neutralizationof the space charge which tends todevelop around this signal grid isprovided by the insertion of a 3.3 Apd

FROM 1N5R.F.

AVC

B.C.0

S.W.

1R5

OM*

B.C.0

005

S.W

455K.C.

TO1N5I.F.

1013+90 V

o B.C.

S.W.

Variable gadder --- 3600on B.C. range

Neutralization in 1 R5 of Defrola Model 61 1 -A

capacitor between grids #1 and #3.Without this component the conver-sion gain of the tube would be serious-ly decreased by displacement currentat high frequencies.

Crosley Model 9-102This a -c powered, broadcast -band

table type receiver employs five tubesplus rectifier. A tuned r -f stage isused, a three gang condenser tuningthe r -f, mixer and oscillator circuits.In the partial diagram is shown thedetails of the r -f amplifier and mixerportion of the schematic.

The first item of note is the useof a low impedance loop and seriescoil to resonate the input circuit,along with the associated variablecondenser and parallel trimmer. The

Front end details of Crosley Model 9-102

control grid of the 7A7 amplifiertube is coupled to the tuned circuitby a .001 Afd coupling capacitor.

In the plate circuit of the r -f stagethere is a transformer for transferringthe signal voltage to the mixer. Theprimary of the transformer is broad-ened by the use of a 27K ohm shuntresistor. The transformer secondaryis tuned by another section of thegang condenser. Signal is coupled tothe 7Q7 mixer grid by a variabletrimmer capacitor. This unit servesto resonate the circuit at the highfrequency end of the band.

AVC potential is supplied to boththe r -f and mixer circuits via shuntresistors of large value.

Hoffman Model C-503This elaborate instrument provides

radio reception on three bands, phonoreproduction and recording on discs.Twelve tubes plus rectifier are em-ployed. Four 6K6 tubes are used inthe output stage. Of particular inter-est is the tone control stage. A 6J5tube is biased in such a manner thatits gain averages just over unity.Adequate amplification is providedin the previous 6SQ7 and following6J5 stages. Refer to the partial sche-matic for details.

A high impedance is provided inthe cathode to ground circuit by use



NEW PRODUCTS0\\1 s''TIVW

TV CAPACITORSTelevision service needs for small, yet de-

pendable, 6000 volt capacitors for 85.0 highhumidity operation are now filled by the newType TVQ capacitors announced by SpragueProducts Company, North Adams, Mass.

REPLACEMENT SPEAKERThe Receiver Division of the General Elec-

tric Company is now offering its specially de-signed outdoor type speaker to all its fran-chised parts distributors for replacement saleto drive-in theaters. This outdoor speaker fea-tures a cork gasket, specially treated cone andimpregnatqd terminal board in addition to thestandard G -E metal foil base voice coil.

RCA

203L5

VIDEO TRAPThe new video -circuit trap 203L5 is designed

for use in the plate circuit of the 1st videoamplifier of television receivers to attenuatethe 4.5 megacycle intercarrier beat frequency.The design utilizes a fixed, ceramic capacitorshunting a low -Q inductance tuned by an ad-justable iron core.

For further information write: Tube De-partment, Radio Corporation of America, Har-rison, N. J.

TV ANTENNAA new antenna design for the elimination

of co -channel interfeience is announced byTechnical Appliance Corporation, Sherburne,N. Y., pioneer manufacturers of TV, FM andAM antenna systems.

TUBE TESTERThe Hickok Electrical Instrument Co. an-

nounces a new, lightweight portable tubetester, Model 600. This instrument containsthe Dynamic Mutual Conductance circuit andprovides accurate testing of AM, FM, or TVtubes.

HIGH VOLTAGE CONTROLTo provide that safe insulation factor re-

quired of controls used in TV, oscillographend other high -voltage circuits, Clarostat Mfg.Co., Inc., Dover, N. H., announces an improvedhigh -voltage -coupler feature, type 56-125, inconjunction with most types of Clarostat con-trols on special order.

MIDGET -CAN ELECTROLYTICSIn keeping with the trend towards still more

compact radio -electronic assemblies, AerovoxCorp. of New Bedford, Mass., now comes upwith the latest Type PRS midget -can elec-trolytic capacitors in new reduced sizes. Thisfact is dramatized in the accompanying illus-tration showing an Aerovox Type PRS 450volt 8 mfd. Dandee alongside a regular sizecigarette. This new Dandee measures only13/16" in diameter by 11h" long!

NEW MINIATURE TUBESSeven new miniature double diode -triode

radio tubes providing improved rectificationof weak signals and better minimum volumecontrol operation have been announced bySylvania. In the new miniature tube groupare types 6BT6 and 12BT6 with operatingvoltages indentical with older types 6AT6and 12AT6 ; types 6BK6 and 12BK6 to re-place types 6AV6 and 12AV6; types 6BU6and 12BU6 to replace types 6BF6 and 12BF6;and a new miniature, type 26BK6, having nocomplementary type but operated at the samevoltages as others in the group with the ex-ception of its 26.5 volt, 70 milliampere heater.

METER KITHeath Company, Benton Harbor, Michigan

announces the new Heathkit Handitester Kit


"An inferior set with a good antenna

will always outperform a better set

with a poor antenna/" From FM -TV

Magazine, June 1949.

SINGLE BAY

INLINE TV ANTENNAMODEL 114-005

Operates over all chan-nels and covers bothhigh and low bands

For proved effectiveness,

specify

AMPHENOL

INLINEANTENNAS

TWO BAY HIINLINE TV I

ANTENNA I

MODEL i114-302

Designed for .long-distancereception and

for fringe-area residents.

FOR CUSTOMERSAn inadequate antenna sacrifices more than 10% of theTV picture quality. The customer wants the best TV picturereception. He depends on the TV dealer for a TV set atthe price he can afford and for an antenna that is the beston the market.

FOR SALESSEE -ABILITY IS SELL -ABILITY and the better the TV pic-ture, the more satisfied the set owner will be. "When yousell a picture, you build customer satisfaction." And cus-tomer satisfaction sells more TV sets.

FOR INFORMATIONIt takes selling punch and selling knowledge to put themost into a selling talk that will sell the potential TV viewer.American Phenolic Corporation has prepared "Sell a TVPICTURE", a comprehensive 16 page sales manual to helpyou sell TV.

-THIS BOOK IS FOR YOU"Sell a TV PICTURE" gives exact,scientific TV data in carefully chosenterms that are easily understood. Writetoday and ask for your free copy of"Sell a TV PICTURE": AMERICANPHENOLIC CORPORATION, 1830 SO.54TH AVENUE, CHICAGO 50, ILL.

AMPHENOL1.1111111\1_31111ANTENNAS

AMERICAN PHENOLIC CORPORATION 1830 SO. 54TH AVENUE CHICAGO 50, ILLINOIS


becauseTELREX CONICAL "V" BEAM ANTENNAS

are performance -provedUp to 200 miles over land and up to300 miles over all -water TV paths

For both remote or high signal areas, Telrex Conical WindowMounts, Stacked Bi-Directionals and Stacked Arrays are the an-tennas dealers and service men can depend upon for consistentlygood results. Each type is thoroughly engineered in the laboratory,service -tested in the field and built for long service life. Using TelrexConical Antennas on every installation is one sure way to better,brighter pictures and a minimum of service call backs. Ask your dis-tributor for catalog or write direct outlining your antenna problems.

TELREX ANTENNAS COVER CHANNELS .2 TO 13AND FM NO HIGH FREQUENCY HEAD NEEDED

TELREX

MODEL 1 X -BD

Bi-Directional Hi -GainConical "V" Beam

Broad Band Full Audioand Video Band Pass

Low Vertical AngleNon -Varying Center Impedance2 to 1 Front to Back RatioUses 72, 150 or 300 OhmTransmission Lines

Universal Mounting Clamp

PATENT

TELREX MODEL 4X -TV2 Bay Uni-Directional

Conical "V" BeamBroad Band-FullAudio and Video

Band Pass

Low Vertical Angle,Minimum Reflections

Maximum Signal

to Noise Ratio4 to 1 Front to Back

Ratio Ali Frequencies

Non -Varying Center Impedance

Universal Mounting Clamp

TELREX MODEL 2X -BD

PENDING .

TELREX

SUPEREX

Bi-Directional StackedConical "V" Beam

Low Vertical Angle

Extremely High Signal toNoise Ratio

Constant Center Impedance

Uses 72, 150 or 300 Ohm

Transmission LinesUniversal Mounting Clamp

FOR THE ULTIMATE IN BI-DIRECTIONAL GAIN, USETELREX MODEL 4X BD.

With antenna

angle arm adjust-able through 180°azimuth arc.For high signal areas.

Window, wall or attic mountingwith flexible orientation possible. 2 -piecearm is provided. Short arm is useful for parallel -to -wall orientation. Second arm permits other thanparallel orientation.

0 0 0 0 OOOOOOOOOO

ALL TELREX ELEMENTS ARE MADE OF LASTING DURALCOPYRIGHTED 1949

AMERICA'S ilOrOUTSTANDING

TELEVISIONBEAM

NEW JERSEY

NEW PRODUCTS[from page 26]

featuring a large quality 8" built-in meter.1% percision ceramic divider resistors areused. 400 microampere meter movement comesalready mounted in the case protected fromdust during assembly.

PHONO CARTRIDGE

A new Series 34 Orthogonal (vertical -type)Torque Drive crystal phono cartridge-withW and W hole spacing-has been designedas replacement in RCA 45 rpm changers, byEleetro-Voice, Inc., Buchanan, Michigan.

MINIATURE HEADSET

The Telex Esrset, a single -phone headsetthat slips onto the ear and weighs only % anounce, was recently released by Telex, Inc.,Minneapolis, manufacturers of electro-acousticequipment and hearing aids.

NEW ISOLATION TRANSFORMERSThree isolation transformers, with 60, 150,

and 250 -VA capacities respectively, have justbeen announced as new catalog items by Chi -



BUY THE BEST . THE V.O.M.A. THAT DOES MORE

TriplettModel630

83750Dealer Net

In the relatively short time since Model 630 wasintroduced to the trade it has steadily risen to thetop in sales. The reason is obvious. Here is a Volt -Ohm -Mil -Ammeter that does more . . . has provencomponents ... and will give a lifetime of satisfac-tion. All the engineering skill and facilities of theindustries' largest manufacturer of Volt -Ohm -Mil -Ammeters joined forces to make it outstanding inevery way. Look over all the features and you toowill buy Model 630.

VOMA JR.-A NEW VOLT -OHM -MIL -AMMETERHandy "POCKET-SIZE LABORATORY"By TriplettVOMA Jr. MODEL 666-R has many of the design features ofthe popular Model 630:

1. Switch and controls flush with panel.2. Enclosed molded selector switch.3. Exclusive Unit construction -resistor housing integral with switch.4. Resistors Precision wire wound and permanent film type.5. Resistance Measurements to 3 Megohms.6. Batteries with spiral spring contacts, easily replaced.

VOMA Jr. MODEL 666-R ... $24.50U.S.A. Dealer Net Price

Note: Model 666-11H The Original Pocket -Size Lab-still a favorite withmany. U.S.A. Dealer Net $22.00.

NOTE THESE SENSATIONALIMPROVEMENTS:

* Individual Scales with separated spacing are easy toread.

* Large 53i Inch Meter In Special Molded Case UnderPanel.

* Resistance Scale Markings from .2 Ohms to 100Megohms -Zero Ohms Control Flush With Panel.

* Only One Switch-Has Extra Large Knob 2W' Long-Easy To Turn-Flush With Panel Surface.

* Enclosed New Molded Selector Switch and insu-lated resistor housing in unit construction.

* All Resistors Are Precision Film or Wire WoundTypes For Permanent Accuracy.

* Batteries Easily Replaced-Balanced Double -Con-tact Grip. Spiral Spring-Battery for Ohms test dueto low drain insures shelf -life usage.

TECH DATAD.C. VOLTS: 0-3-12-60-300-1200-6000 at 20,000 Ohms/VoltA.C. VOLTS: 0.3-12-60-300-1200-6000 at 5,000 Ohms/VoltD.C. MICROAMPERES 0-60 at 250 MillivoltsD.C. AMPERES 0.12 at 250 MillivoltsD.C. MILLIAMPERES 0-1.2-12-120, at 250 MillivoltsOHMS: 0.1000-10,000; (4.4 Ohms and 44 Ohms center scale)MEGOHMS: 0-1-100'(4400-440,000 at center scale)DECIBELS: -30 to +4, +16, +30, +44, +56, +70OUTPUT: Condenser in series with A.G. Volt rangesHigh voltage Probes available, extra; also plug-in shunts for othercurrent measurements to suit special needs.

Laboratory Standard Model 630-A-All scales onthis model are hand drawn and hand stepped, usedwith mirror for extreme accuracies, beyond the averageservicing needs of the model 630.Triplett Model 630-A Dealer Net $47.50

TRIPLETT ELECTRICAL INSTRUMENT COMPANY BLUFFTON,OHIO,U.S.A.In Canada: Triplett Instruments of Canada, Georgetown., Ontario

TECH DATAD.C. VOLTS: 0.10.50-250.1000.5000, at 1000 Ohms/VoltA.G. VOLTS: 0.10.50-250-1000.5000, at 1000 Ohms/VoltD.C. MILLIAMPERES: 0.10-100, at 250 MillivoltsD.C. AMPERES: 0.1, at 250 MillivoltsOHMS: 0-3000-300,000.... (20-2000 at center scale)MEGOHMS: 0-3 (20,000 ohms center scale)


NEW PRODUCTS[from page 28]

sago Transformer Division, Essex Wire Corp-oration., 3051 W. Adison St., Chicago 18, Ill.

Designed for dual purposes, they are suit-able either for (1) adjusting high or low linevoltages to operate radio, television, and otherequipment on a normal 115 volts, or (2) pro-moting safer, more efficient servicing or ex-perimental work on electronic gear by isolat-ing chassis grounds from line grounds-par-ticularly useful in eliminating shock hazardon AC -DC television sets.

TV ANTENNACommunications Measurements Lab.. Inc.,

120 Greenwich St., N. Y. 6, N. Y., announces

their new Vidi-Master TV antennas which aredesigned to provide broad band performanceand flexibility of operation and adjustment.

Let GI's Sgo-0-7/t/voieeti Line-upsolve your record speed problems

MODEL TS -45-78-33Y3 R. P. M. General Industries'newest rim -drive phonomotor, designed to accommodateall types of records now on the market. Features includestandard narrow flange turntable for compact installation,and ingenious speed -change mechanism which is bothsimple and positive in operation.

Single -speed phonograph motors for 78, 45 or331/4 R. P.M. operation . . . dual -speed motorsfor any two -speed combination of the above ...and a low-cost rim -drive motor for all threespeeds ... that's the complete General Industriesline-up which gives your designers and engi-neers the solution to their "which speed touse" problems.And no matter what the choice, you get thesame dependable Smooth Power motors whichhave made General Industries a leading name,as well as the oldest name in the phonomotorfield. GI Smooth Power motors are engineeredto meet exacting performance standards, andto provide trouble -free long life for the ultimateuser. Every one of the GI motors is dynamicallybalanced to the degree necessary for excellentreproduction of records.For full details, specifications and dimensionsof General Industries' complete Smooth Powerline of phonograph motors, recorders andrecord changer -recorders, write today for acopy of the latest GI catalog.

TWO -SPEED MOTORS

General Industries offers you achoice of six different dual -speedcombinations to take any two ofthe standard 2 -pole rim -drive mod-els, or a 4 -pole rim -drive modelfor use in instruments in which theultimate in performance standardsis desired.

SINGLE -SPEED MOTORS

All five of the famous GI SmoothPower single -speed phonographmotors now are available in yourchoice of 78, 45 and 3314 R.P.M.speeds. Both 2 -pole and 4 -polemotors afford a complete range ofselection to meet every operatingrequirement.

DEPARTMENT K ELYRIA, OHIO

TV & RADIO NOISE FILTERSFour new television and radio noise filters

developed for use on motors, generators andR. F. heating equipment, are announced bythe Cornell-Dubilier Electric Corporation, SouthPlainfield, New Jersey. Three of these are in-tended for low voltage motors and generators.

other-NF-10084-is designed for equip-ment operation from power lines up to 250VAC -DC. Current ratings range from 20 to350 amperes. Also shown above are the NF -10085 -88 series of feed-thru capacitive TV andRadio Noise Filters.

TV ANTENNAChannel Master Corp., Ellenville, N. Y. an-

nounces the design and production of a newtype antenna, the Fan Flector. This is thebroad band antenna combining two principlesof antenna engineering, fan type elements foruniform high impedance, and Vee type align-ment of these elements for narrow lobe, highgain characteristics on the high band.

EASY -UP TOWER MODEL 200An improved tower for television receiving

antennas, the Model 200, has recently been an -


tounced by the Easy -up Tower Company, 3800[Mae Ave., Racine, Wisconsin.The new model is a triangular type, pre-

abricated steel tower designed for either resi-ential or commercial use. Antenna height of0 feet above rooftop is achieved with theasic 3 -section tower anchoring a 10 -foot pole.There still greater height is needed, from one -o five 10 -foot extension sections can conven-ently be added.

TV QUIZ[from page 20]

band is grounded for safety.(6). T w o dark non -conducting

lines showing maximum lim-its, anywhere within whichthe focus coil may be placed.

(c) Acid etched area on the neckof the glass, providing a non-slip placement for the coil.The acid etching is done atthe factory after test place-ment shows proper limits.

(d) The coil is slipped on the neckof the tube, then slipped upuntil it strikes the flare of thetube. Here it is cemented inplace. It is impossible toplace the focus coil at animproper point under theseconditions.

(e) None of the above. The coilis slipped along the neck un-til placed approximately half-way between base and flare,between gun -accelerating an-ode and deflection coils. (Thetube carries no markings forfocus coil placement.)

ANSWERSTO TV QUIZ

1. Observe Fig. 5. Under the leftand rule the current moving awayrom the observer generates a mag-etic field moving counterclockwise.

DIRECTIONOF

ELECTRONCURRENT

ig. 5. Direction of generated mag-netic field for current shown.

Tote eye of observer at left. He wouldse a counterclockwise magnetic field.2, There would be no change in

se drawing, since an electron beam

Fig. 6. Magnetic force on conductor

per:iliti. in a vacuum acts exactlylike ihe drift of electrons along a con-ducior.

. Look again at Fig. 5. The pic-ture the observer's eye SCOS is Si1OW11.

in the side Vii 1'7(1. t. Now I lien,

the lines of 1, 110 111:1L'Ilf't joincertain lineof force el' the con-ductor. occurs when the linesare in cohitinction. ((ioing the samexv:IY.) Certain other lines can the otherside of the conductor oppose lines ofthe magnet, causing cancellat offorce there. The re-ult, then, i= thatthe conductor itself for the electronbeam itself, if H phi ,:ie;dfypushed by the 11111',

I Com ',nod on ncl r prL:e!

Nowybearee Redeeme% AIDS TELEVISION

PROGRESS WITH TH

MODEL AT _1

TELEVISIOBOOSTE

New Astatic aooster Has GainEquivalent to Two Ordinary toasters. . . Covers All 12 Channels with

Very Uniform Gain . Eliminates Sacri-fice of Good Sound for Good Picture, or Vice

Versa, with Dual -Tuning.

ADDITIONALIMPORTANTFEATURES

I. Self-contained powersupply operating from115 volt, IS cycle ACPower line.

2. On -off switch allowsbooster to be switchedin or out of the circuitat will.

3. Recessed pilot light indi-cates when booster is on.

4. Beautiful, furniture -finishmahogany cabinet (8,h"

wide x 6,/2". high x

Pit" deep) to comple-ment fine home furnish-ings.

S. Simple to install and op-erate-complete instruc-tions with each unit.

ASTATIC RESEARCH - which has led the march ofprogress in various sound repro'cluction fields sincethe company first pioneered in crystal microphones,

phonograph pickups, cartridges, parts and accessories -now brings major new advantages in reception and tuningto the television field. The new Astatic device which makesit all possible is the Channel Chief, Model AT -I, a radicallyimproved type of television booster. The common failing ofmany boosters - showing a "peak" on some channels and"fall -off" on others-has been eliminated. The Channel Chiefprovides extremely high gain - equivalent of two conventional boosters - uniform on all 12 television channels. Itsdual controls allow separate tuning of picture and sound.with no sacrifice of one for the other. Or, if one signal isweak and the other adequate, both controls may be adjustedto the weaker to bring it in strong. A variable gain controlpermits reduction of signal strength to prevent picture dis-tortion when the signal input is greater than that requiredfor good definition. Altogether, the results are the consider-able extension of fringe areas, good reception in areaspreviously rated as unsatisfactory, easier tuning and addedselectivity on any receiver, elimination of the need for ex-pensive outdoor antennas within service areas. The in-creased selectivity serves to reduce drastically, or eliminate,interference from adjacent channels, amateur and commer-

cial fundamentals and harmonics in the re-ceiver's I.F. range, FM stations and oscillatorsof nearby FM, TV and short wave receivers. Noother booster can do so much .. . for your in-stallation and service business, for the televi.sion receiver owner. Write for added details.

1ADIO SERVICE DEALER OCTOBER, 1949 31

BACK NUMBERS of "RSDOrder them now - the supply is low.

JANUARY 1946Applying Neg. Feedback in Audio Amps.New Philco FM CircuitRMA Resist. & Conds. ChartFEBRUARY 1946Applying Neg. Feedback in Audio Amps.Service Market in Industrial ElectronicsBallast Tube & Plug-in Resistor ChartJULY 1946Distortion-Determining the Cause, Part I

Ohmmeters, Cond-Testers, Cap. -Met. Part2 MultivibratorsSEPTEMBER 1946Transconductance-Reading Tube TestsHow Is Your Grid Biased, Part 2Centralized Radio ServicingNOVEMBER 1946The TV Opportunity-Installing & ServicingDon't Miss "Hidden" Profits, Part I

Service Market in Industrial ElectronicsDECEMBER 1946Modernizing Sets by Using New RectifiersDeflection Generators in TVGuide for Miniature Electron TubesAnswers to FM Servicing ProblemsMAY 1947Oscillator & Power Supply TroublesIon -Trap in C -R TubesP -A System Design & Applications, Part I

JUNE 1947Simplified Set CheckingP -A System Design & Applications, Part 2TV Installing Is A Specialty BusinessServicing 3 -Way PortablesJULY 1947Frequency Modulation, Part I, antenna

fundamentals & signal shifting effectsAutomatic Gain Control Circs. in TV SetsUsing Conventional Sig. Gen. for FM Align.AUGUST 1947TV R -F Circuits DescribedFM, Part 2, receiver circuit fundamentalsTV Antenna Installation ProblemsOCTOBER 1947Add Record-players to Modernize Old SetsP -A Fundamentals & ComplexitiesModern TV KitsFEBRUARY 1948High Speed ServicingVisual AlignmentIncome Tax DeductionsMARCH 1948Know Your Tube TesterTV Power SuppliesA-C/D-C Battery Set CircuitsAPRIL 1948Video I -F Circuits & ApplicationsComputing What Price to ChargeUsing 'Scopes For Radio ServicingMAY 1948FM Set Alignment ProcedureVideo DetectorsHow Vectors Simplify ServicingSignificance of Power Factor and Q

JUNE 1948Amplifier Checking by Signal InjectionApplications of Gas Type TubesModern TV KitsJULY 1948Television's Service OutlookVideo AmplifiersBad Acoustics Cured ElectricallySEPTEMBER 1948De -emphasis In FM Set CircuitsVideo Amplifiers, D -C RestorersSimple WattmeterOCTOBER 1948Projection TVDistributed CapacitanceTV Picture TubesHigh Voltage Test ProbesNOVEMBER 1948Sweep GeneratorsTV Picture Tubes155 Loudspeakers, Voltage -FedMaking Good TV InstallationsFM -TV Antenna Mast SupportDECEMBER 1948Checking Video & Synch Waveforms by

CRO.Magnetic RecordingProjection Television, Part 2JANUARY 1949Checking Video & Synch Waveformt by

CRO, Part 2Feedback & Phase InversionTuned FiltersTV Picture Tube ChartFEBRUARY 1949Test Equip. Symposium Issue:

CROs - VTVMs - Sq. Wave Generators -Markers - Multimeters - Kilovolters -

High Voltage Probes, etc.MARCH 1949Test Equip. Symposium Issue:

Signal Generators - Tube Testers - etc.Markers For Visual AlignmentTV KilovoltmeterSignal Generators ChartProjection TV, Part 3JUNE 1949Direct View Englarging LensModern Tape Recorders, Part 2Custom Building High Fidelity Circuits,

Part 2JULY 1949Picture Tube High Voltage SystemsHigh Quality Tuner AnalysisAmateur TV InterferenceAUGUST 1949Capacitance Bridges - Operation &

ApplicationsLegal Opinion on TV Service "Policies"A New TV & FM Sweep Generatorfransformerless Power SuppliesCeramic Piezo-Electric Devices

I

NAME

ADDRESS

CITY

RADIO SERVICE DEALER MAGAZINE342 MADISON AVE., NEW YORK 17, N. Y.

Please send me theback numbers checkedhere . .

The price is 35c. foreach copy unless 10 ormore are ordered. If 10or snore are ordered theprice is 25c. each copy.

Jan.Feb.JulySept.

1946194619461946

JulyAug.Oct.Feb.

1947194719471948

July 1948 Sept. 1948 Oct. 1948 Nov. 1948

June 1949July 1949Aug. 1949

Nov. 1946 Mar. 1948 Dec. 1948Dec. 1946 Apr. 1948 Jan. 1949May 1947 May 1948 Feb. 1949June 1947 June 1948 Mar. 1949

I remit herewith $ for the copies ordered at c. each.

MIIMN 11111M

ZONE STATE.......M=11111=.= OEM. EIF.

force toward the lines of least resist-ance (cancelled lines).

Thus, in Fig. 5 the beam wouldmove toward the reader. In this casesolution (e) would be correct. On theother hand, viewed in Fig. 6 the beamwould move toward the right.

In electrical motors the same prin-ciple is used to move the wire con-ductor itself. Since this is connectedto the rotor, the whole shaft turns,causing the motor to operate by ro-tation.

4. In Fig. 3 the effect of the horse-shoe magnetic beam upon the mag-netic field of the electron beam,though less, is similar to that occur-ring in Fig. 2. In this case, however,because of the angle a torque, or twist-ing action is exhibited, effectively di-verting the beam as intended.

5. The special angle is zero de-grees, or parallel. If the horseshoemagnetic field is parallel to the cur-rent beam, no force will be exertedupon the beam. Since the magneticlines of the two fields would be ex-actly at right angles to each other,there would be neither addition norcancellation of lines, hence no inter-action.

6. (e) is correct. As long as thefocus coil is placed approximately asdescribed it generally suffices, sinceadjustment of current through thecoil completes the final focus. (If fo-cus control range is not wide enoughto achieve proper beam -focus, then coilhas been improperly p 1 a c e d, andshould be moved one way or the other.)

SERVICING P.E.

[from page 22]

the use of a potentiometer which con-trols the tube grid voltage directly.In such cases the filament, grid, screenand plate voltages may be taken fromseparate windings of a transformer.However, this is mentioned merely toacquaint you with possible circuitvariations, since there is little or nodifference in the adjustment proce-dure. It must be emphasized, though,that the directions given here forsensitivity adjustment are general. Ifthe maker's instructions for adjust-ment are available they should befollowed implicitly.

Assuming that you are adjusting aforward type unit, the general pro-cedure would be somewhat as follows:after setting up the lamp unit andobtaining the maximum amount oflight on the target, turn on the am-plifier and allow the usual period forwarm-up. Cover the phototube so asto block off all light. Now turn thesensitivity adjustment until the re -

32 RADIO SERVICE DEALER OCTOBER, 1949 , I

lay contacts just close, then back offe adjustment until they again open.

Now remove the cover from the photo -tube so that full light from the lampreaches it, and note whether the relaycloses properly. Alternal ely cover andilluminate the phototube and notewhether the relay operation is posi-tive. Further adjustment may be need-ed. If you do not get quick, positiveclosure of the relay contacts eachtime the tube is illuminated, advancethe sensitivity adjustment slightly;on the other hand, if the relay tendsto stick or does not open immediatelyupon cutting off the light supply, theadjustment has been too close andmust be backed off.

In adjusting a reverse type unit,the procedure is exactly opposite fromthat outlined above. Since the relayis to close in the absence of light onthe phototube cathode, the procedurewould be to adjust the sensitivitycontrol with the tube illuminated.Turn the adjustment until the relayis energized, then back off the ad-justment until the contacts just open.When the tube is then darkened therelay should close properly; if itdoes not, repeat the adjustment asdescribed in the preceding paragraph.

(To be continued)

TRADE FLASHES[from page 12]

modern picture tube manufacturingland engineering facilities at Electron-ics Park, which will be in addition toits picture tube operations at Buffalo,N. Y. To house the new Syracusetube facilities, the company is con-verting and adding to an existingbuilding. When completed later thisyear, the building will have 152,000square feet of manufacturing spacein addition to engineering and officeareas.

South River Obtains Patent" South River Metal Products, manu-iacturers of the Chimney Mount

1 Antenna Base, have recently beenI assigned U. S. Patent 2,482, 575, pat-ent protecting their chimney mounts.

Rider Announces TV No. 3Announcement has been 'received

from John F. Rider Publisher, Inc.,tlrat the forthcoming Rider TelevisionManual Volume 3 will be publishedin a new size substantially enlarged.The page size will' be approximately12 x 15 inches, a dimension hithertoused only for special double spreadpages. This change in binder dimen-sions will reduce the number of folds

of the giant size pages to a single one,thus making for greater convenienceand extended life of the page.Philco Wall Charts

Giant, blown -up schematics thatmake perfect wall charts and giveyour shop that technical, professionalappearance are now available at. anominal cost at your Philco distri-butor.

Four Schematic Wall Charts areavailable under the following partnumbers:

PR 1795, shows Models 50-T1105and T1106.

PR 1796, shows Model 50-702.'PR 1797, shows Model 49-1278,

Code 123.PR 1798, shows Model 48-1001.

Du Mont UHF -VHF ProgramThe general public has a larger

stake that it realizes in the televisionhearings held before the Federal Com-munications Conimission September26, it was stated by Dr. Allen B. DuMont, President of the Allen B. DuMont Laboratories.

On the face of it, the purpose ofthe hearing was to review the alloca-tions outlined by the FCC on July

$ELL APPEAL CAPITALS

ccricr6-6

%%/%1k1WWV.,4 EDNAYL AL IRGGHI TN GTELEVISION

A SMASHHIT WITH

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because .

* It's easy to ottoch to any tele

vision set.

* Fits console or table models.

* Makes imageFOUR TIMES

BIGGER.

* No eyestrain! Noglare! No

distortion!

*Morecontrast! Sharper

out-

lines!

* Wide angle view! 3 -dimen-

sional impression!

BIGGER PROFITS FOR YOU

because .

* Duotone Daylight lens is available in all sizes.

* Lens available tinted or clear.

* Generous dealer discounts are our policy!

LENS PRICES start as low as $12.95

Also Available . . . . FILTERS

* Duotone Daylight Television Filters scientificallytinted for maximum clarity, heightened contrast,elimination of eyestrain. 7" $2.00, 10" $3.50,12" $5.00, 15" or 16" $7.50.

CONTACT YOUR DISTRIBUTOR OR DUOTONE DIRECT

THE INC.

799 Broadway New York 3, N. Y.

MAKERS OF THE FAMOUS DUOTONE NEEDLES


ARE YOUREADY

FOR UHF

THE MEGAUGNER TYPICAL TV RECOVER

L THE MEGA -SWEEP CATHODE RAY OSCILLOGRAPH

A modern test set-up is shown here inoperation . . . With these Megaline instru-ments you service VHF and are ready forUHF.

With Megaline instruments you are al-ways ahead in the TV business. Our engi-neers are constantly working to keep youahead. This actually saves you money be-cause if you buy Megaline test equipmentyou will not have to replace it with com-pletely new instruments whenever a newband is announced.

The Megaline will not be obsolete whennew bands are announced.

A MEGA -SWEEP sweeping oscillatorwith single dial continuous tuning from50 kc to 1000 mc.An accurate marking device (MEGA-LIGNER) 19-49 mc pip type markwhich cannot overload receiver or dis-appear in traps.

RF Marker with crystal accuracy forsound carrier of each TV channel.Engineering Service Division through-out the United States.

THE CALIBRATED MEGA -SWEEPCovers Video, I.F., VHF and UHFTelevision Bands.Single control t ming over frequencyrange. Sweep c-nter frequency variablefrom 100 kc to 900 mc by single control.Standard models now in field can bemodified at factory. $75.00Price: $425.00 F.O.B. Factory

THE MEGALINER A TV IF marker generator.

Frequency range 19-49 mc.Pip does not disappear in traps.Can be used as CW signal source.Includes 4.5 mc Crystal Oscillator.Price : $150.00 F.O.B. Factory

Write for catalog .Prices outside U.S.A. and Canada

10% higher.

KAY ELECTRIC CO.30 Maple Avenue Pine Brook, N. J.

Caldwell 6-4000

11, and also to look into color televi-sion proposals. The Du Mont Programprovides for 81 channels and rests onthese eight factors:1. To utilize the twelve present com-

mercial VHF channels to the fullestextent, thereby providing four chan-nels per city for most of the 140metropolitan districts (as describedby the 1940 census).

2. To utilize 48 UHF channels, eachsix megacycles wide, to assure ad-equate service to other communities.

3. To reserve twelve additional UHFchannels, each six megacycles wide,to protect smaller communities, notyet ready to embrace TV and insurethat adequate frequencies will beavailable when they are ready.These will be assigned on a first-

come, first -served basis.4. To set aside nine further UHF

channels for non-commercial educa-tional broadcast applications. Theseare to be assigned- on a first -come,first -served basis and used at fullmetropolitan power.

5. To allocate VHF and UHF fre-quencies in such a manner as toprovide a minimum of four chan-nels in most .metropolitan commu-nities to assure competitive opera-tion and a wide choice of programs.

0. To minimize the intermixture ofVHF and UHF assignments to re-duce, or eliminate, the need for setowners to buy converters or forstation owners to utilize transmit-ters for two supplementary frequen-cies.

7. To provide for the best long termoperating plan" for television, bydesignating certain cities, now hav-ing a limited VHF service, asfuture UHF cities in the long termplan.

8. Finally, it proposes allocations ofUHF channels so as to minimizeinterference between stations andreceivers.

N. Y. Audio Fair

First details have been announcedof the program being planned for thetechnical sessions of the Audio Fair,which will be sponsored by the Socie-ty for presentation at the Hotel NewYorker in New York October 27, 28and 29. At the technical sessions tobe held over the three day period ofthe Fair will be papers of interest toaudio engineers and the related fields.

I.R.E. Fall MeetingThe 1949 Radio Fall Meeting,

formerly known as the Rochester FallMeeting, will be held October 31st,November 1st and 2nd at Hotel

Syracuse, Syracuse, New York ac-cording to an announcement by Vir-gil M. Graham, chairman of the RadioFall Meeting Comthittee and direc-tor of technical relations for Sylva-nia Electric Products Inc.

Garcelon Joins HytronFrederick H. Garcelon has joined

the sales force of the Hytron Radio

& Electronics Corp. He will operateout of the New York ' Hytron officeand will contact equipment manufac-turers.

New Mobile ServiceFormation of the first national

network of independent radiotele-phone stations for mobile service tothe general public was announcedrecently in a statement filed with theFederal Communications Commissionin behalf of the National MobileRadio System.

Organization of the new inter-state system is regarded as one ofthe most significant of recent radio-communication developments. It willoffer a practical and unprecedented-ly low-cost means of communicationbetween occupants of automobiles,trucks, buses and other vehicles withoffices or homes hundreds of milesdistant. The network also has im-portant potentialities as an auxiliarycommunications system in event ofnational emergency or disaster.New Utah Line

Utah, one of the oldest names inthe radio industry, announced a com-plete new line of original equipmentand replacement radio speakers andreplacement transformers. All Utahproducts have been re -engineered andchanges have been made which makethe new line outstanding.

To Manufacture 16 Inch TubeThe manufacture of metal 16 -inch

TV picture tubes at the new SaltLake plant of Eitel-McCullough, Inc.,was the subject of a disclosure by W.W. Eitel, President of the firm._


HALF AS LARGE ...TWICE AS GOOD!ASSOCIATION

NEWS

Philadelphia Radio Servicemen'sAssociation, Inc.As reported in Field Findings in

this issue, the PRSMA Radio andTelevision. Convention and Exhibitheld in Philadelphia, Sept. 18, 19 and20, was an outstanding success.Attendance figures neared the 5,000mark: Congratulations to one of themost progressive and aggressive Serv-icemen's organizations in the U.S.A.

The complete program for the threeday,: convention tells better than allth*words that can be written thestory of this remarkable achievement.Dallas Radio Sales

6 Service Ass'n., Inc.A clinic featuring Sparton TV was

held on August 8. The annual elec-tion meeting ushered in a new slateof officers; among which were: Pres.,Egon Pflughaupt; Vice-Pres., W. J.InMan, and. Sec-Treas., T. P. Rob-inson.

A surprise shower by fellow mem-bers of the Dallas Radio and. Serviceassociation restocked shelves of H. H.Hirsch after his merchandise andequipment were lost early in Juneduring a flood in Garland, a Dallassuburb. Left to right, E. Pflughaupt,association vice-president, and T. P.Robinson, secretary -treasurer, hadHirsch -some of the new equipmentpresented to him by the organization.Empire State Federation of

Electronic Technicians AssociationsA change in the dates of the Ro-

chester Area TV Course meeting wasmade necessary because of the needfor obtaining a meeting place largeenough to hold -the audience antici-pated., The new dates are as follows:1) Sept. 26, 1949; 2) Oct. 10, 1949;3) Oct. 24, 1949; 4) Nov. 14, 1949;5) Nov. 28, 1949; 6) Dec. 12, 1949;7) Jan. 9,1950; 8) Jan. 23, 1950;


f777

STUD

TERMINALSO Smaller - better. That's whythe new Aerovox dual and triplemidget -can electrolytics are asmash hit with servicemen.

Stud terminals replace usualriveted terminals. Reduce tubulardiameter 40%. Advanced electro-lytic capacitor art further reducesbulk. Note comparison betweenusual dual and new Dual Dundee.

To top it all, insulated wire leads 1in place of bare wiresl Also insu-lating sleeves over stud terminals.No danger of "shorts" even intight spots.

GO AEROVOX IFor faster, easier, more -money serv-icing, ask your Aerovox jobber forthese Dandeesi Ask for latestAerovox catalog-or write us.

FOR RADIO -ELECTRONIC AND

INDUSTRIAL APPLICATIONS

AEROVOX CORPORATION, NEW BEDFORD, MASS., U. S. A.':

SALES OFFICES IN ALL PRINCIPAL CITIES Export: 13 E. 40th ST., NEW YORK 16, N. V.

Cable: 'ARM' In Canada: AEROVOX CANADA LTD., HAMILTON, ,ONE,

LITTELFUSEELECTRONIC ASSORTMENT-A SERVICE "MUST"Packed in an attractive plastic case, the fuses andholders have been carefully selected to cover your mostfrequent service needs for television, radio, communication instruments,etc. . . You will reuse the plastic case for easy -to -lose parts, fishing tackle,coins, and stamps. Be sure to have the fuse to fit!

LITTELFUSE INCORPORATED 4787 North Ravenswood Avenue, Chicago 40, Illinois


ASSOCIATIONNEWS

[from page 35]

.9) Feb. 13, 1950; 10) Feb. 27, 1950;11) Mar. 13, 1950; 12) Mar. 27, 1950;13) Apr. 10, 1950; 14) Apr. 24, 1950;15) May 8, 1950; 16) May .22, 1950.

Date changes in the Binghamton -Endicott Area for purposes prevent-

ing conflicts with local functions con-sist of moving up the Wednesdaydates to the Tuesdays preceding. Thenew dates are tentatively as follows :3) Philco, Oct. 19, 1949; 4) Westing-house, Nov. 1, 1949; 5) Emerson, Nov.15, 1949; 6) R.C.A.-Radio ServiceDealer Magazine, Dec. 6, 1949; 7)DuMont; Jan. 3, 1950; 8) Motorola,Jan. 17, 1950; 9) Precision, Jan. 31,1950; 10) Hickok, Feb. 14, 1950; 11)

"Did over $5000 additional business installing ESPEY chassis"De Young, Ithaca, N. Y.

THERE ARE THOUSANDS OF OUT-MODED RADIOS IN YOUR "BACK YARD"JUST WAITING TO BE REPLACED . . AT YOUR SUGGESTIONHere is the custom-built AM -FM chassis that means BIGGER PROFITS for you!

The NEW ESPEY model 511

SPECIFICATIONS

Supplied ready to operate, complete withtubes, antennas, speaker and all necessaryhardware for mounting in a table cabinetor console, including esutcheon. Power re-quirements 105/125 volts AC, 50/60 cycles.Power consumption -85 watts.Chassis Dimensions: 131/2" wide x 81/2" highx 10" deep.Carton Dimensions: (2 units) 20 x 14% x10% inches.Net Weight 16% pounds each.Sold through your favorite parts distributor.

WRITE FOR CATALOGUE D1 CONTAIN-ING COMPLETE SPECIFICATIONS ON

THIS AND OTHER MODELS.

FEATURES1. AC Superheterodyne AM -FM Receiver.2. Improved Freluency Modulation Circuit,

Drift Compensated.3. 12 tubes plus rectifier and electronic

Tuning Indicator.4. 3 dual purpose tubes.5. Treble Tone Control:6. 6 -gang tuning condenser.7. Full -range bass tone control.8. High Fidelity AM -FM Reception.9. Automatic volume control.

10. 13 watt (max.) Push -Pull Audio Ouput,11. 12 inch PM speaker with Alnico V Mag-

net, 25 watts rating.12. Indirectly illuminated Slide Rule Dial.13. Smooth, flywheel tuning.14. Antenna for AM and folded dipole an-

tenna for FM Reception.15. Provision for external antennas.16. Wired for phonograph operation.17. Multi -tap output trans., 4-8-500 ohms.18. Licensed by RCA.19. Subject to RMA warranty, registered

code symbol #174,Makers of fine radios since 1928.

TEL. TRafalgar 9.7000

MANUFACTURING COMPANY, INC.528 EAST 72nd STREET., NEW YORK 21,. N. Y.

Insure BETTER Television Service to YourCustomers! ....adadipteevD&Elyzeti

HIGH VOLTAGE ANDELECTROLYTIC TUBULAR

TELEVISIONCAPACITORS

Especially Engineered for Television Circuits byINDUSTRIAL CONDENSER CORP.

The economical quality line for replacement. Industrial Condenser Corp.,manufacturers of Capacitors, exclusively brings you highest quality forthe particular requirements of Television at exceptionally attractive prices!Special Capacitors are Pyroteen impregnated for low power factor, highinsulation resistance, high operating temperatures, Oil, Pyroteen, Waxand Electrolytic Capacitors. Finest materials throughout.

Ask Your Jobber for our Attractive Prices Today!Or write' for Bulletin 1095. Industrial makes quality Capacitors forTelevision, Radio, every electronic and industrial application-all types.

Send for Complete Catalog

INDUSTRIAL CONDENSER CORP3243 N. CALIFORNIA AVENUE CHICAGO 18, ILLINOIS

Sales offices In all principal cities

Modern plant built by Industrial Con-denser Corp., for manufacture ofCapacitors only.

DuMont, Feb. 28, 1950; 12) G. E.,Mar. 14, 1950; 13) Kay, Apr. 4, 1950;14) Service Magazine, Apr. 18, 1950;15) DuMont, May 2, 1950; 16) May16, 1950.Associated Radio TV Servicemen

of New YorkThe first of the ESFETA TV Lec-

ture series was held on Sept. 14, JohnF. Rider shown below delivered a most

interesting lecture on "The Nature ofTV." The second lecture, "Antennasand Transmission Lines," was pre-sented by Messrs. L. H. Finneburghand L. Klein, of the Ward ProductsCorp. Very capably presented andwell received.

CIRCUIT COURT[from, page 25]

of the 2200 ohm and 22K resistors.Only the portion across the 2200 ohmsection is applied to the grid as d -cbias. The by-pass capacitor is only .002

Hoffman Model C-503, 1st audio

,pfd. The plate circuit contains a .01iifd capacitor as part of the high -fre-quency tone control. Note that provi-sion is made to disconnect the entiretone control network during recording.


Low frequency compensation is de-veloped by the series LC circuit com-prising a 3.7 henry choke and a .5,L4fd capacitor. As the bass control istuned toward the ground end theresonance provided by these compo-nents become more effective and boostof the low end of the audio rangetakes place.

High frequencies are increased asthe high frequency control is turnedtoward the lower end. High cut offtakes place as the control moves uptoward the .01 Afd capacitor. T h ecombination of the two controls makesany combination of tone boost or at-tenuation within the range of theaudio system possible.

MEGALINEU

[from page 19]

ference between the variable oscilla-tor output in the Megaligner and thesweeping output from the Megasweep.

Figure 2 shows the operation ofboth the Megaligner and Megasweepused together. Assume that a televi-sion receiver video i.f. is being alignedand an external oscilloscope is usedas the indicating device. The I axissignal or sweep for the oscilloscope isprovided from the Sweep Output ofthe Megasweep. The Input Cablewhich is a part of the Megaligner isattached to the High Output connec-tor of the Megasweep. This is thejack marked Input (Sweeping Oscil-lator) on the Megaligner. The OutputJack (Sweeping Oscillator) from theMegaligner goes to the converter tubeof the television receiver under testacross a 50 ohm resister to ground.A Y axis signal is provided for theoscilloscope from the detector of thetelevision receiver being tested. ThePip Output from the Megalignerthrough a low capacity shielded leador twisted pair goes directly to theY axis of the oscilloscope. In thismanner the test oscilloscope has asweep time base provided by theMegasweep, a pip connected directlyto the signal terminals and a visualtrace provided by the sweeping ar-rangement of the Megasweep.

The CW Oscillator Output controlsare important to the operation of thisgenerator. On -Off Switch connectsthe CW signal either to the Outputcoaxial connector or to ground. Bymeans of the Increase Control whichis a potentiometer in the output ofthe crystal output circuit, the levelof this 4.5 megacycle signal may beadjusted. Output from the variableoscillator is capacitively coupled tothe center arm of this potentiometer

'icaa&rTELEVISIONGENERATOR

KIT

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'qleaM4etTUBE CHETCKER!

K I /$2950

..lrat."r"t'SIGNAL

TRACER KIT

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NEW

IMPEDANCEBRIDGE SET

$695°

$345°

I I eathkits are beautiful factory one!.neered quality service instrumentssupplied unassembled. The buildernot only saves the assembly laborcost but learns a great deal aboutthe construction and features of theinstrument. This knowledge aidsmaterially in the use and mainte-nance of the equipment. Heathkitsare ideal for and used by leadinguniversities and schools throughoutthe United Mates. Each kit is com-plete with cabinet, 110V 60 cycletransformer (except Handi-Tester),all tubes, coils assembled and cali-brated, panel already printed ,chassisall punched; formed and plated,every Dart supplied. Each kit is pro-vided with detailed instruction man-ual for assembly and use. Heathkitsprovide the perfect solution to theproblem of affording complete serv-ice equipment on a limited budget.Write for complete catalog.

R.F. SIGNALGEN. KIT

$195?

BATTERYELIMINATORKIT

.giecie44-a

VACUUM TUBEVOLTMETER KIT

2 4 5°

HEATH COMPANYBENTON HARBOR, 12

MICHIGAN EXPORT DEPARTMENT13 EAST 40th STREET

NEW YORK 16, N.Y. ,CARLE -AREAS-N.Y.

* Cold inorganic -cement coated* Won't blister, peel, flake, crack* Stands up under severe over-

loads* Fixed and adjustable. 5 to 200

watts* Wide selection of resistance

values

YES INDEED, GREENOHMS ARE TOUGHER!* Those green power resistors youfind in better -grade TV sets, oscillo-graphs, test instruments, transmit-ters and industrial equipment, areGREENOHMS.Take a tip! For your "stay -put" jobs

- where you can't take a chancewith component breakdowns - whenyou don't want to lose your profitby going back again - use GREEN -OHMS. They'll never let you down!And they cost less!

Ask our jobber for Greenohms.Try them once!

Latest catalog on request.

CLAROSTAT MFG. CO., INC. DOVER, NEW HAMPSHIRE In Canada: CANADIAN MARCONI CO., LTD.Montreal, P. 0, and branches

1 9 4 9


T;;7lEigTONESmeet changingpickup needs!

A

NOW a full line of Titone's amazingceramic pick ups-made by famousSonotone! All with these great basicfeatures: Full frequency (responsefrom 50 to 10,000 cycles.) Bell -likesupertone makes new or old playersthrilling. Climate -proof, moisture -proof, fungus -proof! Lightest pressuresaves needle wear, revives worn records.NO needle talk! NO crystals, magnets,filaments to fail. NO pre -amplifiers.Performs perfectly for years!

tillOgiI?gotif.3 -tali. PICO

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est 'Near,.OrdererItiet7540. .

$195

0 T

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Call your Jobber or write toSONOTONE, Box 5, Elmsford, N. V.

so that this control may adjust theamount of signal output from eitherthe crystal or the variable frequencyoscillator. This potentiometer can onlybe used when the CW Oscillator Out-put On -Off Switch is on the On posi-tion. By this means either of the twooscillators in the Megaligner may beused to provide a radio frequencysignal to the output coaxial cable.

A Calibrate Switch is a momentaryB supply switch which, when helddown, provides plate voltage for boththe variable frequency oscillator andthe crystal oscillator. This switch isto be used when it is desired to useharmonics of the 4.5 mc crystal oscil-lator to check calibration of the vari-able frequency oscillator. As exam-ples, the following check points maybe used: the fifth harmonic on thelow frequency band is 22.5 mc; thesixth harmonic on the same band is-27.0 mc. On the high band the seventhharmonic is 31.5 mc and the tenthharmonic is 45.0 mc.

This calibration of the variable fre-quency oscillator is best carried outby using the Megaligner and an os-cilloscope. With the Pip Output ter-minals directly connected to the ver-tical input terminals of the scope thecontrols should be set as follows: CWOscillator Switch in Variable Posi-tion, CW Oscillator Output Switchin On position, CW Oscillator Outputand Pip Amplitude controls at halfopen position. The calibrate switch isdepressed and the variable frequencyoscillator is adjusted to beat with thedesired harmonic of the crystal os-cillator by tuning the variable fre-quency oscillator until a visible beatnote appears on the oscilloscope. Theproper trimming adjustments are bestobtained from the manufacturer'sdata supplied with each instrument.

PA TECHNIQUES[from page /7]

expensive amplifier driving a lowefficiency loudspeaker produces nolouder nor more intelligible a sounddelivery than a low powered inexpen-sive amplifier driving an efficientloudspeaker. The difference in costis much greater in the amplifier de-partment.

Now when we have a given effici-ency and power and widely spreadour sound projection, the loudness ofsound heard at a given location willbe less than that from the same unitdriving a narrow beam horn. Stateddifferently, horns with a wide spreador angle of coverage will sound lessloud at a given distance, even on thehorn axis, than will directional horns

REJECT INTERFERENCE ON

TV -FM -AM!Qr\--)

NEWMEISSNER

WAVE -TRAPPERS

AVAILABLE IN 5 MODELS6 to 13 mc, 13 to 27 mc

27 to 54 mc ,54 to 108 mc108 to 216 mc

You can now attenuateinterfering signals on

fundamental or harmonic frequencies withthese new, highly efficient tunable wavetraps. Several may be connected in seriesif interference exists on more than onefrequency. Efficient with any balanced orunbalanced line from 50 to 400 ohmsimpedance. $5.00 List Price

NEW MEISSNERLINE FILTERS

(Grounded & Shielded)Reject interference

from electric shavers,electric fans, food mixers, vacuum cleaners,etc. 300 watt rating. $6.50 List Price

See Them At Your Dealers

0.45,54,,e 2/4_ MFG. DI VI SION090' Maguire Ind Inc.

Mt. Carmel. Illinois

Perfectly balanced, functional in design.the DRAKE "insta-heat" Soldering Gungives you all the features you'vewanted: A full 135 watts, this gun hasthe perfectly located VISA-LITE, thatkeeps work always in full view-evenin dark difficult corners. The solderingtip is easily - instantly - removable, usingonly a screwdriver. See your distributor.

DRAKE ELECTRIC WORKS, INC.3656 LINCOLN AVENUE CHICAGO 13


ISOLATION

BENCH TRANSFORMER

REGULATE YOUR LINE VOLTAGE

TO FIT YOUR REQUIREMENTS

N-303 VARI-VOLT JUNIOR$15.00 DEALER NET

A voltage regulating isolation -trans-former to make your bench test volt-age exactly what you want...on 117Vline, variable from 95 to 145 volts...if line drops to 90, variable from 75to 115V....output adjustable in 11/2

volt steps...metered output voltage...capacity up to 250 Watts intermittant, 50-60 cycles...for radio andtelevision receiver testing at under orover voltage...to isolate "hash" andlive ground from AC -DC equipment...controled voltage for meter calibra-tion...speed up or retard heating oflight soldering iron...and for manyother similar uses.

See your local Halldorson distrib-utor for complete line of replacementtransformers ...exact duplicates televi-sion and auto Vibrator transformerreplacements, or write direct to us forcomplete information. THE HALL-DORSON COMPANY, 4500 Ravens-wood Avenue, Chicago 40,

HandorsOlt

$1.00 to $5.00 PAIDfor "SHOP NOTES"

Write up any "kinks" or "tricks -of -the -trade" in radio servicing that youhave discovered. We will pay from $1to $5 for such previously unpublished"SHOP NOTES" found acceptable.Send your data to "Shop Notes Editor,"RADIO SERVICE DEALER, 342 MadisonAve., New York 17, N. Y. Unused manu-scripts cannot be returned unless accom-panied by stamped and addressed re-turn envelope,

with identical driving units. Fromthis it can be seen that two efficientdirectional radiators can best cover anecessarily wider spread requirement.

InstallationA few prime factors cannot be de-

nied as regards assembly and distor-tion of sound equipment despite thefact that space limitations are oftensevere. Not listed in their importancethese are:

1. Visibility -- Clear view of activities to be serviced by an operatoris desirable. Where mixing of micro-phones is required this feature is im-perative for customer satisfaction.

.2. Accessibility - The rear 'aswell as the front of all componentsshould be readily accessible for maintenance or replacement.

3. In cramped quarters or tropicalclimes, lack of adequate ventilationmay result in costly failures or inter-ruption to service causing a loss offuture business. Units should be, sep-arated and fans applied when re-quired.

4. Low Level Circuits-All pro-gram input circuits must be shielded,grounded and physically isolated frommagnetic fields such as those emittedby power transformers, building pow:-er lines and your own high level cir-cuits. To avoid ground loops shield-ing should be insulated from contactwith any other equipment or groundedunits. One single insulated wireshould be run from each unit's groundterminal to one good common ground.It is well to remember that, low impe-dance lines carry more current for agiven power than do high impedancelines; also that the strength of a mag-netic field is a function of the currentproducing it. Furthermore the use oftwisted pair for low level circuitsoften reduces foreign pickup. Induc-tion in one bucks equal voltage in-duced in the other. Similarly the mag-nitude of a generated field from powercircuits using twisted pair is less thanwhen straight parallel leads are used.Lastly, when balanced input circuitsallow longer low level cable runs, costsof lengthy high level transmissionlines may be minimized by spottingthe amplifiers closer to the loudspeak-ers. The inclusion of preamplifiers be-tween microphone and main amplifieroften cures input ailments otherwisecontrary where long mike lines arenecessary.

5. High Level Circuits - Proper-ly matched and distributed lines toloudspeakers may usually be run to-gether with control circuits such asswitching, relay, or signal control cir-cuits providing these do not carryprogram material. Usually loudspeak-er lines are relatively short in a trans-

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SNAP!YOUR ANTENNA IS

ASSEMBLED

THE OAK RIDGE 6FM and TV ANTENNAS

FEATURING THE AMAZING

SNAP -LOCK**Pat. Pending

Revolutionary four -second assembly.Just snap, it out and it's fully assembled.Extremely rugged -1/2 inch aluminumelements.Completely pre -assembled - No loosehardware.

We manufacture a full line of qualityFM and TV antennas, including Hi -La's,Conicals, In -lines, Vee's,..Stacked Arrays.Ask your local jobber for a demonstra.tion. Inquiries invited.

OAK RIDGE ANTENNAS239 East 127th Street, New York 35, N. Y.h16aufacturing Division of Video .Television, Inc.

Write for Catalog S-1

AWED'S NEW

1950 CATALOG!

'196 PAGES-Everything inRadio andElectronics

GET RADIO'SLEADING BUYING GUIDEService Technicians and Engineers: AL-LIED'S 1950 Buying Guide brings you allthe new releases and money -saving val-ues-from the world's largest stocks oftest instruments, amplifiers, P.A. sys-tems and equipment, tubes, parts, tools,books and accessories-ready for instantexpert shipment. Send today for yourFREE new 196 -page ALLIED Catalog.

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ALLIED RADIO

mission sense, and hence may be con-sidered as a pair of conductors havingresistance and capacitance responsiblefor power losses which must be keptto a minimum. Impedance matchingfrom source to load is a must.

To save space and mathematics wereproduce here very practical figuresfor low impedance lines in Table 1.The figures given are distances in feetbetween driving amplifier and load. Amaximum of 15% power loss is allowedas generally satisfactory at these verylow impedances. Only short lines andshort wire sizes are permissable at thelowest impedance values where as thetable shows smaller conductors andlonger runs permissable for the highervalues included within Table 1.

For transmission lines having high-er impedance values the reader is re-ferred to the very useful curves ofFig. 3. At the higher impedance valuesno such losses as above are tolerated.These curves are drawn up allowinga maximum loss of 0.5 db. The reasonfor overlapping discrepencies between

600

,.,453000000

200

loo0CL 50

4in 0 0 o 0 0N u7 O 0

N tO

,t)

LENGTH OF RUN IN FEET

OOO

Fig. 3. High impedance values

table and curves is due to more rigidtolerances for the curves which covervalues more easily controlled. Thereason for strict tolerances is obvious.Even a 3 db loss in these output cir-cuits means one half of the powercapacity of the system is sleuced downthe drain. Wire size in output circuitsmeans much for two reasons :

1. Fire hazards result when con-ductors are too small and thus causeoverheating.

2. Loss of power due to excessiveresistance of inadequate conductorsmay cause the sound operator to em-ploy over -expensive driving amplifi-ers.

Again we suggest the reader reviewthe four articles listed at the start ofthis article. Study of the curves andfigures here presented should helpsave initial costs plus time and monieslost due to trial and error.

ATTENTIONSouth River Chimney Mounts

are patent protectedU. S. Patent 2482575

Write for the new South RiverCatalog illustrating complete lineof television accessories including

the

NEW! THRIFT CHIMNEY MOUNTMODEL T20

Low List Price $2.50 completeand the NEW

3" WALL BRACKET Model T3Low List Price $100 complete

SOUTH RIVERMETAL PRODUCTS CO., INC.

Dept. RD, 17 Obert St., South River, N.J.

TRAINEDMEN

AVAILABLESolve your trained man-power shortage by em-ploying C.T.I. gradu-

ates. These men have completed a rigidcourse of training. What they've learnedhas been PRACTICAL, because most oftheir training period was spent IN THESHOP. We probably have graduates fromsour area. Write for prospectus on Avail-able men. (No employment fees).

COMMERCIAL TRADES INSTITUTE1400 Greenleaf Dept. P 105-7 Chicago 26

AD INDEXAerovox Corporation 35Air King Products Co., Inc. 13

Allied Radio Corp. 40American Phenolic Corp. 27American Television & Radio Co 39Asfatic Corporation, The 31

Brach Mfg. Corp., L. S. 6Clarostat Mfg., Inc. 37Commercial Trades Institute 40Drake Electric Works, Inc. 38Duotone Co., Inc. 33Espey Mfg. Co., Inc. 36G. E. Co. (KenRad Div.) 7

General Industries Co., The 30Halldorson Company, The 39Heath Company 37Hytron Radio & Elec. Corp. . Cover 3Industrial Condenser Corp 36International Resistance Co 14

Kay Electric Co 34Ken Rad Tube Div. of G. E. Co 7Littelfuse, Inc 35Mallory & Co., Inc., P. R Cover 2Meissner Mfg. Div 38Oak Ridge Antennas 40Ohmite Manufacturing Co 12

Permoflux CorporationRadiart Corporation, The 3

RCA (Electron Tubes) Cover 4RCA (Test Equipment) 8

Rider Publisher, Inc., John F. I I

Sonotone Corp 38South River Metal Products Co 40Sprague Products Co 10

Sylvania Elec. Products, IncTelrex, Inc 28Triplett Elec. Instru. Co. 29


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WITH "TUNE-UP"...RCA's campaign to tap new business for you

OVER 10 MILLION RADIOS need ser-vicing! How many will YOU ser-

vice? Because most people think therepair price will be too high, millionsof sets stay unserviced.

Now-RCA offers you a way to over-come the public's reluctance to havefaulty radios checked . . . a year-round,personalized promotion campaign.

Now-you can offer your customers,through professional posters, displays,

mailing pieces, advertisements and spotradio announceents, a special tune-upjob at your own price. The promotionpieces tell the customer just what hewill get for his money!

Here's your chance to make extra profitsfrom one of the greatest service promo-tion campaigns ever launched! Lose notime in getting the special flier that tellsthe whole story. Your RCA Tube Dis-tributor has a copy, waiting for you.

ALWAYS KEEP IN TOUCH WITH YOUR RCA TUBE DISTRIBUTOR

Now-The RCA Pricing Kit! Priceyour merchandise and make moresales! Use this Kit to price merchan-dise-in the window, on counters,and in the store. Learn how to getyour Kit today ... see your RCA TubeDistributor while the supply lasts!

RADIO CORPORATION of AMER/CAELECTRON TUBES HARRISON, Newr.

Documents

CTOBER, 1949...121/2" 125Z-16 15000 2" 16 ohms 20 751/2" 155Z-16 15000 2" 16 ohms 35 NEW catalog available upon request. Write for your FREE copy! PERMOFLUX CORPORATION Two Factories